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Summary There is a lack of appropriate melanoma models that can be used to evaluate the efficacy of novel therapeutic modalities. Here, we discuss the current state of the art of melanoma models including genetically engineered mouse, patient-derived xenograft, zebrafish, and ex vivo and in vitro models. We also identify five major challenges that can be addressed using such models, including metastasis and tumor dormancy, drug resistance, the melanoma immune response, and the impact of aging and environmental exposures on melanoma progression and drug resistance. Additionally, we discuss the opportunity for building models for rare subtypes of melanomas, which represent an unmet critical need. Finally, we identify key recommendations for melanoma models that may improve accuracy of preclinical testing and predict efficacy in clinical trials, to help usher in the next generation of melanoma therapies.

Immunotherapy and targeted therapy are both effective against melanoma, but their combination is frequently toxic. Here, we investigated whether the sequence of immunotherapy (IT; anti-PD1)->targeted therapy (TT; ceritinib-trametinib or dabrafenib-trametinib) was associated with improved antitumor responses in mouse models of BRAF- and NRAS-mutant melanoma. Mice with NRAS- (SW1) or BRAF-mutant (SM1) mouse melanomas were treated with either IT, TT, or the sequence of IT->TT. Tumor volumes were measured and samples from the NRAS-mutant melanomas were collected for immune-cell analysis, single-cell RNA sequencing (scRNA-Seq), and reverse phase protein analysis (RPPA). scRNA-Seq demonstrated the IT->TT sequence modulated the immune environment, leading to increased infiltration of T cells, monocytes, dendritic cells (DCs) and natural killer (NK) cells, and decreased numbers of tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDCSs), and regulatory T cells (Tregs). Durable responses to the IT->TT sequence were dependent on T-cell activity, with depletion of CD8(+), but not CD4(+) T cells, abrogating the therapeutic response. An analysis of transcriptional heterogeneity in the melanoma compartment showed the sequence of IT->TT enriched for a population of melanoma cells with increased expression of MHC class I and melanoma antigens. RPPA analysis demonstrated that the sustained immune response induced by IT->TT suppressed tumor-intrinsic signaling pathways required for therapeutic escape. These studies establish that upfront immunotherapy improves the responses to targeted therapy in BRAF- and NRAS-mutant melanoma models.

Background The impact of biologic aging on immune checkpoint inhibitor (ICI) toxicity and efficacy is underexplored in metastatic melanoma (MM). In peripheral blood T lymphocytes (PBTLs), biologic aging is characterized by changes in T‐cell composition and cellular senescence. Whether indicators of PBTL biologic aging vary in MM patients or can be used to predict premature ICI discontinuation (pID) is unknown. Methods We prospectively collected PBTLs from 117 cancer‐free controls and 46 MM patients scheduled to begin pembrolizumab or nivolumab monotherapy. Seventy‐four mRNAs indicative of T‐cell subset, activation, costimulation/inhibition, and cellular senescence were measured by Nanostring. Relationships between each mRNA and chronologic age were assessed in patients and controls. Candidate biomarkers were identified by calculating the hazard ratio (HR) for pID in patients divided into low and high groups based on log‐transformed mRNA levels or the magnitude by which each mRNA measurement deviated from the control trend (Δage). Area under the curve (AUC) analyses explored the ability of each biomarker to discriminate between patients with and without pID at 6 months and 1 year. Results Fifteen mRNAs correlated with chronologic age in controls, including markers of T‐cell subset, differentiation, cytokine production, and costimulation/inhibition. None of these mRNAs remained correlated with age in patients. Median follow‐up was 94.8 (1.6‐195.7) weeks and 35 of 46 patients discontinued therapy (23 progression, seven toxicity, and five comorbidity/patient preference). Elevated pretherapy CD8A (HR = 2.2 [1.1‐4.9]), CD45RB (HR = 2.9 [1.4‐5.8]), and TNFRSF14 (HR = 2.2 [1.1‐4.5]) levels predicted pID independent of Δage‐correction. CD3ε, CD27, and FOXO1 predicted pID only after Δage‐correction (HR = 2.5 [1.3‐5.1]; 3.7 [1.8‐7.8]; 2.1 [1.1‐4.3]). AUC analysis identified Δage‐CD3ε and Δage‐CD27 as candidate predictors of pID (AUC = .73 and .75). Conclusions Correlations between transcriptional markers of PBTL composition and chronologic age are disrupted in MM. Correcting for normal, age‐related trends in biomarker expression unveils new biomarker candidates predictive of ICI outcomes.

How the measurement of aging biomarkers in peripheral blood T-lymphocytes (PBTLs) is influenced by cell composition is unclear. Here, we collected peripheral blood and isolated CD3+ PBTLs from 117 healthy couples between the ages of 21 and 72. Each sample was profiled for Horvath epigenetic clock (DNAm), p16INK4a expression, cytomegalovirus (CMV) seropositivity and 74 mRNA markers of PBTL subtype, differentiation, immune checkpoints, and cytokine production. Correlations between individual aging biomarkers (DNAm or p16INK4a) and PBTL mRNAs were corrected for chronological age, sex, and couple. DNAm measurements correlated with CMV seropositivity as well as PBTL mRNAs indicative of effector function (CD8A, EOMES, TBX21, GZMB), poor proliferative capacity (KLRG1, CD57), differentiation (CD45RO, CD45RA), and immune checkpoints (PDCD1, TIGIT, LAG3, CD160, CD244). In contrast, only three PBTL mRNAs, CD28, CD244, and p14ARF, showed a significant association with p16INK4a. p16INK4a expression also showed a weaker association with immunosenescent PBTL subsets than DNAm in flow cytometry analyses. These data suggest that PBTL composition has a greater influence on DNAm than p16INK4a and link accelerated epigenetic aging to immunosenescent phenotypes.

Autologous stem cell transplant (ASCT) is the standard of care for patients with multiple myeloma (MM). The clinical significance of peripheral blood T lymphocyte (PBTL) immunologic changes associated with ASCT is poorly understood. Here we evaluated T cell transcriptional messenger RNA profiles and immunophenotypes to correlate immunologic senescence, exhaustion, and anergy with clinical endpoints in a cohort of patients with MM undergoing ASCT. ASCT induced global transcriptional T cell changes and altered molecular levels of markers of T cell subtypes, T cell activation, and exhaustion. These included reduced CD4/CD8 ratio, skewing toward the Th1 subset, reduced expression of costimulatory receptors CD27 and CD28, heightened T cell activation, and increased expression of immune modulatory molecules LAG3 and PD1. Multicolor flow cytometry experiments confirmed altered circulating CD4 and CD8 subsets and skewing toward differentiated effector cells. Moreover, ASCT promoted an exhausted immunophenotype in CD3+CD4+ subsets and a senescent immunophenotype in CD3+CD8+ subsets. Subset-specific altered expression was also seen for surface molecules with immunomodulatory function. ASCT affected soluble levels of molecules with immunomodulatory function by increasing plasma HVEM and TIM3. High molecular LAG3 level was associated with inferior event-free survival post-ASCT (hazard ratio=5.44; confidence interval, 1.92 to 15.46; P = .001; adjusted P [controlling for false discovery rate] = .038). Using a comprehensive evaluation of PBTLs on a molecular and phenotypic level, we have identified that ASCT induces global T cell alterations with CD4 and CD8 subset-specific changes. Moreover, LAG3 emerged as an early biomarker of adverse events post-ASCT. These findings will support the development of treatment strategies targeting immune defects in MM to augment or restore T cell responses.

A single, neonatal UVB exposure drives greater UV-signature production in Braf- than Nras-mutant murine melanomas., BRAF-mutant melanomas are more likely than NRAS-mutant melanomas to arise in anatomical locations protected from chronic sun damage. We hypothesized that this discrepancy in tumor location is a consequence of the differential sensitivity of BRAF and NRAS-mutant melanocytes to ultraviolet light (UV)-mediated carcinogenesis. We tested this hypothesis by comparing the mutagenic consequences of a single neonatal, ultraviolet-AI (UVA; 340–400 nm) or ultraviolet-B (UVB; 280–390 nm) exposure in mouse models heterozygous for mutant Braf or homozygous for mutant Nras. Tumor onset was accelerated by UVB, but not UVA, and the resulting melanomas contained recurrent mutations affecting the RING domain of MAP3K1 and Actin-binding domain of Filamin A. Melanomas from UVB-irradiated, Braf-mutant mice averaged twice as many single-nucleotide variants and five times as many dipyrimidine variants than tumors from similarly irradiated Nras-mutant mice. A mutational signature discovered in UVB-accelerated tumors mirrored COSMIC signatures associated with human skin cancer and was more prominent in Braf- than Nras-mutant murine melanomas. These data show that a single UVB exposure yields a greater burden of mutations in murine tumors driven by oncogenic Braf.

Background Senescence is a tumor suppressor mechanism activated in stressed cells to prevent replication of damaged DNA. Senescent cells have been demonstrated to play a causal role in driving aging and age-related diseases using genetic and pharmacologic approaches. We previously demonstrated that the combination of dasatinib and the flavonoid quercetin is a potent senolytic improving numerous age-related conditions including frailty, osteoporosis and cardiovascular disease. The goal of this study was to identify flavonoids with more potent senolytic activity. Methods A panel of flavonoid polyphenols was screened for senolytic activity using senescent murine and human fibroblasts, driven by oxidative and genotoxic stress, respectively. The top senotherapeutic flavonoid was tested in mice modeling a progeroid syndrome carrying a p16INK4a-luciferase reporter and aged wild-type mice to determine the effects of fisetin on senescence markers, age-related histopathology, disease markers, health span and lifespan. Human adipose tissue explants were used to determine if results translated. Findings Of the 10 flavonoids tested, fisetin was the most potent senolytic. Acute or intermittent treatment of progeroid and old mice with fisetin reduced senescence markers in multiple tissues, consistent with a hit-and-run senolytic mechanism. Fisetin reduced senescence in a subset of cells in murine and human adipose tissue, demonstrating cell-type specificity. Administration of fisetin to wild-type mice late in life restored tissue homeostasis, reduced age-related pathology, and extended median and maximum lifespan. Interpretation The natural product fisetin has senotherapeutic activity in mice and in human tissues. Late life intervention was sufficient to yield a potent health benefit. These characteristics suggest the feasibility to translation to human clinical studies. Fund NIH grants P01 AG043376 (PDR, LJN), U19 AG056278 (PDR, LJN, WLL), R24 AG047115 (WLL), R37 AG013925 (JLK), R21 AG047984 (JLK), P30 DK050456 (Adipocyte Subcore, JLK), a Glenn Foundation/American Federation for Aging Research (AFAR) BIG Award (JLK), Glenn/AFAR (LJN, CEB), the Ted Nash Long Life and Noaber Foundations (JLK), the Connor Group (JLK), Robert J. and Theresa W. Ryan (JLK), and a Minnesota Partnership Grant (AMAY-UMN#99)-P004610401–1 (JLK, EAA).

Distinct NRAS mutants are enriched in various tumor types. Here, we generated a suite of fully congenic, conditional, Nras knock-in mouse models (LSL-Nras Q61R, -K, -L, -H, -P, -Q; G12D and G13D, -R) to test the hypothesis that melanocyte transformation requires functions specific to the NRAS mutants enriched in human melanoma (Q61R and Q61K). Consistent with the rarity of NRAS codon 12 and 13 mutants in human melanoma, spontaneous melanomas were rare or absent in mice expressing NRAS G12D, G13D or G13R. Mice expressing less common codon 61 alleles (Q61H, Q61P) also developed few or no tumors. NRAS Q61R, Q61K, or Q61L expression, by contrast, induced rapid melanoma onset with high penetrance. Cohorts of heterozygous mice containing one LSL-Nras Q61R and one LSL-Nras Q61K, -L, -H, -P, or -Q allele were generated to assess potential interactions between NRAS mutants. The ability of each Nras variant to substitute for an Nras Q61R allele was consistent with its own ability to drive spontaneous melanoma formation. However, LSL-Nras Q61Q/Q61R mice rarely developed tumors. In vitro experiments in mouse embryonic fibroblasts (MEFs) highlighted activation of the MAPK pathway as a defining difference between tumorigenic and non-tumorigenic NRAS mutants. Enhanced MAPK activation was associated with the promotion of BRAF-BRAF and BRAF-CRAF dimers. These results support the development of cancer preventative strategies specific to the properties of the commonly observed RAS mutants in each tumor type.

Background: Older adults with hematologic malignancy (HM) are a growing demographic and providing effective treatments that balance toxicity and health related quality-of-life (HRQL) is imperative. The well-studied and utilized chemotherapy toxicity tool, the Cancer and Aging Research Group (CARG) chemotherapy toxicity score, has not been validated in hematologic malignancies. Methods: The primary objective of this study was to validate the predictive ability of the CARG score for grade 3-5 toxicity in newly diagnosed (ND) patients >60 years with HM. This was a prospective longitudinal study with 4 study visits: baseline (pre-therapy), visit 2 (Day 90), visit 3 (Day 180), and end-of-study (EOS) which occurred at the earliest of the following events: progression, transplant, or 1-year from baseline. The CARG score was evaluated at baseline. HRQL (PROMIS-GHS) and physical function measured by short physical performance battery (SPPB) were assessed longitudinally at all visits. Treatment toxicity using the NCI CTCAE (version 5.0) were captured monthly, and the worst grade of each type of chemo-related adverse event (AE) was recorded and summarized for each patient. Wilcoxon signed-rank test was used to test if variables changed significantly across visits. Fine and Gray model was used to associate comprehensive geriatric metrics and CARG score with the development of grade 3-5 chemotherapy-related toxicity with death as the competing risk, and Cox model was used to analyze overall survival (OS). Results: Ninety-seven patients with hematologic malignancy (myeloid n=34, lymphoma n=35, plasma cell n=28) were enrolled. The median age was 70 years (range 60-88) with a median 159 days on study (range 1-435). Baseline evaluations: ECOG PS was 0-1 in 69 (85%), median IADL score was 13 (range 5-14), median MOS physical health score was 44.4 (range 0-100), median self-reported KPS was 80% (50-100%), and median comorbidity score was 6 (range 2-12). PROMIS median scores improved from baseline (32, range: 12-49) to EOS (35, range: 16-47, p=0.05). Median SPPB scores improved significantly from baseline (5, range 0-12) to EOS (9, range 0-12, p=0.005). During the study period, 75 patients had 334 grade 1-2 AEs, and 42 patients had 82 grade 3-5 AEs. Hematologic toxicities were more common with 36 (37%) patients having anemia (30 grade 1-2, and 6 grade 3-5) and 11 (11%) patients having febrile neutropenia (all grade 3-5). In multivariable analysis, significant risk factors associated with grade 3-5 toxicity (p Conclusions: The CARG chemotoxicity score was not predictive of grade 3-5 toxicities in patients ND with HM, but was univariably associated with OS. Higher SPPB scores were strongly associated with OS. Future studies, evaluating modifications of the CARG score are indicated for patients with HM. Objective measures of function, such as the SPPB, may be a reliable method to stratify treatment intensities for older adults with HM. Disclosures Mims: Glycomemetics: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Aptevo: Research Funding; Leukemia and Lymphoma Society's Beat AML clinical study: Consultancy, Research Funding; Xencor: Research Funding; Kartos Pharmaceuticals: Research Funding; Genentech: Consultancy; Abbvie: Consultancy; BMS: Consultancy; Kura Oncology: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo: Research Funding. Woyach: AbbVie Inc, Loxo Oncology Inc, a wholly owned subsidiary of Eli Lilly & Company: Research Funding; AbbVie Inc, ArQule Inc, AstraZeneca Pharmaceuticals LP, Janssen Biotech Inc, Pharmacyclics LLC, an AbbVie Company,: Consultancy; Gilead Sciences Inc: Other: Data & Safety; AbbVie Inc, ArQule Inc, Janssen Biotech Inc, AstraZeneca, Beigene: Other: Advisory Committee.

Background: Gauging fitness remains a challenge among older adults with hematologic malignancies, and interventions to restore function are lacking. We pilot a structured exercise intervention and novel biologic correlates of aging using epigenetic clocks and markers of immunosenescence to evaluate changes in function and clinical outcomes. Methods: Older adults (n=30) with hematologic malignancy actively receiving treatment were screened and enrolled in a 6-month exercise intervention, the Otago Exercise Programme (OEP). The impact of the OEP on geriatric assessment metrics and health-related quality of life were captured. Clinical outcomes of overall survival and hospital utilization (inpatient length of stay and emergency department use) in relationship to geriatric deficits were analyzed. Results: Older adults (median age, 75.5 years [range, 62–83 years]) actively receiving treatment were enrolled in the OEP. Instrumental activities of daily living and physical health scores (PHS) increased significantly with the OEP intervention (median PHS: visit 1, 55 [range, 0–100]; visit 2, 70 [range, 30–100]; PP=.05). Quality of life (Patient-Reported Outcome Measurement Information System [PROMIS]) improved significantly by the end of the 6-month period (median [range]: visit 1, 32.4 [19.9–47.7]; visit 3, 36.2 [19.9–47.7]; P=.01]. Enhanced measures of gait speed and balance, using the Short Physical Performance Battery scores, were associated with a 20% decrease in risk of death (hazard ratio, 0.80; 95% CI, 0.65–0.97; P=.03) and a shorter hospital length of stay (decrease of 1.29 days; 95% CI, −2.46 to −0.13; P=.03). Peripheral blood immunosenescent markers were analyzed in relationship to clinical frailty and reports of mPhenoAge epigenetic analysis are preliminarily reported. Chronologic age had no relationship to overall survival, length of stay, or emergency department utilization. Conclusions: The OEP was effective in improving quality of life, and geriatric tools predicted survival and hospital utilization among older adults with hematologic malignancies.

Background Immunization with attenuated malaria sporozoites protects humans from experimental malaria challenge by mosquito bite. Protection in humans is strongly correlated with the production of T cells targeting a heterogeneous population of pre-erythrocyte antigen proteoforms, including liver stage antigens. Currently, few T cell epitopes derived from Plasmodium falciparum, the major aetiologic agent of malaria in humans are known. Methods In this study both in vitro and in vivo malaria liver stage models were used to sequence host and pathogen proteoforms. Proteoforms from these diverse models were subjected to mild acid elution (of soluble forms), multi-dimensional fractionation, tandem mass spectrometry, and top-down bioinformatics analysis to identify proteoforms in their intact state. Results These results identify a group of host and malaria liver stage proteoforms that meet a 5% false discovery rate threshold. Conclusions This work provides proof-of-concept for the validity of this mass spectrometry/bioinformatic approach for future studies seeking to reveal malaria liver stage antigens towards vaccine development.

The overexpression and hyperactivity of p21-activated serine/threonine kinases (PAKs) is known to facilitate tumorigenesis; however, the contribution of cancer-associated PAK mutations to tumor initiation and progression remains unclear. Here, we identify p21-activated serine/threonine kinase 5 (PAK5) as the most frequently altered PAK family member in human melanoma. More than 60% of melanoma-associated PAK5 gene alterations are missense mutations, and distribution of these variants throughout the protein coding sequence make it difficult to distinguish oncogenic drivers from passengers. To address this issue, we stably introduced the five most common melanoma-associated PAK5 missense mutations into human immortalized primary melanocytes (hMELTs). While expression of these mutants did not promote single-cell migration or induce temozolomide resistance, a subset of variants drove aberrant melanocyte proliferation. These mitogenic mutants, PAK5 S364L and D421N, clustered within an unstructured, serine-rich domain of the protein and inappropriately activated ERK and PKA through kinase-independent and -dependent mechanisms, respectively. Together, our findings establish the ability of mutant PAK5 to enhance PKA and MAPK signaling in melanocytes and localize the engagement of mitogenic pathways to a serine-rich region of PAK5.

The Kirsten rat sarcoma (KRAS) proto-oncogene regulates signaling pathways that control proliferation (e.g. MAPK pathway), metabolism and survival (e.g. AKT pathway), and apoptosis (e.g. Hippo pathway). Mutations in KRAS are found in 40% of colorectal cancers (CRC). However, there are no FDA-approved drugs for CRC that target this oncogene. One reason why developing drugs against KRAS is difficult is because a number of different oncogenic alleles have been identified. Thus, an allele-specific approach to target KRAS is necessary. In turn, this approach requires a detailed understanding of their structure and function to drive cell transformation and tissue dysregulation. Our goal is to characterize the function of KRAS A59T in CRC. These alleles are interesting for a number of reasons. First, A59T discriminates retroviral homologues of mammalian RAS from their cellular counterparts. Second, unlike other oncogenic alleles, the KRAS A59T protein undergoes autophosphorylation, the biological function of which is unknown. Third, patient data show that A59 alleles of KRAS frequently co-occur with other genetic alterations in the MAPK signaling pathway, which is uncommon for other KRAS alleles. We hypothesize that KRAS autophosphorylation promotes CRC in a manner that is independent, but cooperative, with the MAPK signaling pathway. To test this hypothesis, we first characterized the function of KRAS A59T and its phosphomimetic A59E using in silico and biochemical techniques, along with classic assays of cell transformation. Next, we generated a new genetically engineered mouse model, K-Ras+/LSL-A59E, in order to test how KRAS autophosphorylation cooperates with other oncogenic mechanisms of MAPK pathway activation to alter colon homeostasis and model colon tumorigenesis. Consistent with our hypothesis, KRAS autophosphorylation and A59E inhibit KRAS-effector interactions that activate the MAPK, AKT, and Hippo signaling pathways. How this change in function alters the ability of K-RasA59E, versus K-RasG12D, to promote hyperproliferation and tumor development in combination with N-RasQ61K and Apc loss in the mouse colon, is currently underway. Ultimately, these studies bring us closer to discovering allele-specific vulnerabilities of KRAS and provide a means to test less understood aspects of oncogenic KRAS signaling. Citation Format: Christian W. Johnson, Elizabeth M. Terrell, Christin E. Burd, Deborah Morrison, Kevin M. Haigis. Characterization of oncogenic KRAS A59 alleles and their cooperation with the MAPK signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 84.

Accumulation of senescent cells over time contributes to aging and age-related diseases. However, what drives senescence in vivo is not clear. Here we used a genetic approach to determine if spontaneous nuclear DNA damage is sufficient to initiate senescence in mammals. Ercc1-/∆ mice with reduced expression of ERCC1-XPF endonuclease have impaired capacity to repair the nuclear genome. Ercc1-/∆ mice accumulated spontaneous, oxidative DNA damage more rapidly than wild-type (WT) mice. As a consequence, senescent cells accumulated more rapidly in Ercc1-/∆ mice compared to repair-competent animals. However, the levels of DNA damage and senescent cells in Ercc1-/∆ mice never exceeded that observed in old WT mice. Surprisingly, levels of reactive oxygen species (ROS) were increased in tissues of Ercc1-/∆ mice to an extent identical to naturally-aged WT mice. Increased enzymatic production of ROS and decreased antioxidants contributed to the elevation in oxidative stress in both Ercc1-/∆ and aged WT mice. Chronic treatment of Ercc1-/∆ mice with the mitochondrial-targeted radical scavenger XJB-5–131 attenuated oxidative DNA damage, senescence and age-related pathology. Our findings indicate that nuclear genotoxic stress arises, at least in part, due to mitochondrial-derived ROS, and this spontaneous DNA damage is sufficient to drive increased levels of ROS, cellular senescence, and the consequent age-related physiological decline. Keywords: Reactive oxygen species, Free radicals, Genotoxic stress, Oxidative lesions, Endogenous DNA damage, Cellular senescence, Aging

Summary To mitigate melanoma risk, sunscreen use is widely advocated; yet, the ability of sunscreens to prevent melanoma remains controversial. Here, we test the tenet that sunscreens limit melanoma risk by blocking ultraviolet radiation (UV)-induced DNA damage using murine models that recapitulate the genetics and spontaneous evolution of human melanoma. We find that a single, non-erythematous dose of UV dramatically accelerates melanoma onset and increases tumor multiplicity in mice carrying an endogenous, melanocyte-specific NRas61R allele. By contrast, transient UV exposure does not alter tumor onset in mice lacking p16INK4a or harboring an NRas12D allele. To block the rapid onset of melanoma cooperatively caused by UV and NRas61R, we employed a variety of aerosol sunscreens. While all sunscreens delayed melanoma formation and blocked UV-induced DNA damage, differences in aerosol output (i.e., amount applied/cm2) caused variability in the cancer preventative efficacy of products with identical sunburn protection factor (SPF) ratings.

Senescent cells within the tumor microenvironment (TME) adopt a proinflammatory, senescence-associated secretory phenotype (SASP) that promotes cancer initiation, progression, and therapeutic resistance. Here, exposure to palbociclib (PD-0332991), a CDK4/6 inhibitor, induces senescence and a robust SASP in normal fibroblasts. Senescence caused by prolonged CDK4/6 inhibition is DNA damage–independent and associated with Mdm2 downregulation, whereas the SASP elicited by these cells is largely reliant upon NF-κB activation. Based upon these observations, it was hypothesized that the exposure of nontransformed stromal cells to PD-0332991 would promote tumor growth. Ongoing clinical trials of CDK4/6 inhibitors in melanoma prompted a validation of this hypothesis using a suite of genetically defined melanoma cells (i.e., Ras mutant, Braf mutant, and Ras/Braf wild-type). When cultured in the presence of CDK4/6i-induced senescent fibroblasts, melanoma cell lines exhibited genotype-dependent proliferative responses. However, in vivo, PD-0332991–treated fibroblasts enhanced the growth of all melanoma lines tested and promoted the recruitment of Gr-1–positive immune cells. These data indicate that prolonged CDK4/6 inhibitor treatment causes normal fibroblasts to enter senescence and adopt a robust SASP. Such senescent cells suppress the antitumor immune response and promote melanoma growth in immunocompetent, in vivo models.Implications: The ability of prolonged CDK4/6 inhibitor treatment to induce cellular senescence and a robust SASP in primary cells may hinder therapeutic efficacy and promote long-term, gerontogenic consequences that should be considered in clinical trials aiming to treat melanoma and other cancer types. Mol Cancer Res; 15(3); 237–49. ©2016 AACR.

Through the progress of basic science research, fundamental mechanisms that contribute to age-related decline are being described with increasing depth and detail. Although these efforts have identified new drug targets and compounds that extend life span in model organisms, clinical trials of therapeutics that target aging processes remain scarce. Progress in aging research is hindered by barriers associated with the translation of basic science discoveries into the clinic. This report summarizes discussions held at a 2014 Geroscience Network retreat focused on identifying hurdles that currently impede the preclinical development of drugs targeting fundamental aging processes. From these discussions, it was evident that aging researchers have varied perceptions of the ideal preclinical pipeline. To forge a clear and cohesive path forward, several areas of controversy must first be resolved and new tools developed. Here, we focus on five key issues in preclinical drug development (drug discovery, lead compound development, translational preclinical biomarkers, funding, and integration between researchers and clinicians), expanding upon discussions held at the Geroscience Retreat and suggesting areas for further research. By bringing these findings to the attention of the aging research community, we hope to lay the foundation for a concerted preclinical drug development pipeline.

Defects in fibroblast or melanocyte function are associated with skin diseases, including poor barrier function, defective wound healing, pigmentation defects and cancer. Vital to the understanding and amelioration of these diseases are experiments in primary fibroblast and melanocyte cultures. Nevertheless, current protocols for melanocyte isolation require that the epidermal and dermal layers of the skin are trypsinized and manually disassociated. This process is time consuming, technically challenging and contributes to inconsistent yields. Furthermore, methods to simultaneously generate pure fibroblast cultures from the same tissue sample are not readily available. Here, we describe an improved protocol for isolating melanocytes and fibroblasts from the skin of mice on postnatal days 0-4. In this protocol, whole skin is mechanically homogenized using a tissue chopper and then briefly digested with collagenase and trypsin. Cell populations are then isolated through selective plating followed by G418 treatment. This procedure results in consistent melanocyte and fibroblast yields from a single mouse in less than 90 minutes. This protocol is also easily scalable, allowing researchers to process large cohorts of animals without a significant increase in hands-on time. We show through flow cytometric assessments that cultures established using this protocol are highly enriched for melanocytes or fibroblasts.

Senescent cells accumulate in multiple tissues as virtually all vertebrate organisms age. Senescence is a highly conserved response to many forms of cellular stress intended to block the propagation of damaged cells. Senescent cells have been demonstrated to play a causal role in aging via their senescence-associated secretory phenotype and by impeding tissue regeneration. Depletion of senescent cells either through genetic or pharmacologic methods has been demonstrated to extend murine lifespan and delay the onset of age-related diseases. Measuring the burden and location of senescent cells in vivo remains challenging, as there is no marker unique to senescent cells. Here, we describe multiple methods to detect the presence and extent of cellular senescence in pre-clinical models, with a special emphasis on murine models of accelerated aging that exhibit a more rapid onset of cellular senescence.

UVR promotes skin cancer through multiple mechanisms, including induction of inflammation, oxidative stress, and DNA damage such as 8-oxoguanine and cyclobutane pyrimidine dimers. We investigated whether the anti-inflammatory activities of aspirin (acetylsalicylic acid [ASA]) could protect against UVB-induced DNA damage and skin carcinogenesis. ASA reduced UVB-induced 8-oxoguanine and cyclobutane pyrimidine dimers in Melan-A melanocytes and HaCaT keratinocytes. Skin from UVB-irradiated C57BL/6 mice receiving 0.4 mg ASA daily by gavage exhibited less inflammation, fewer sunburn cells, and reduced 8-oxoguanine lesions than skin from irradiated control animals. ASA similarly reduced UVB-induced sunburn cells, 8-oxoguanine, and cyclobutane pyrimidine dimer lesions in skin of melanoma-prone TN61R mice, and this was associated with decreased prostaglandin E2 in plasma and skin. These effects of ASA, however, did not delay melanoma onset in TN61R mice exposed to a single neonatal dose of UVB. In SKH1-E mice prone to squamous cell carcinoma, ASA reduced plasma and skin prostaglandin E2 levels and indices of UVB-induced DNA damage and delayed squamous cell carcinoma onset induced by chronic UVB. These results indicate that ASA can protect against UVB-induced inflammation in skin and reduce UVB-induced DNA damage in both melanocytes and keratinocytes. These effects translated into greater chemopreventive efficacy for UVB-induced squamous cell carcinoma than melanoma mouse models.

B cell lymphoma and melanoma harbor recurrent mutations in the gene encoding the EZH2 histone methyltransferase (EZH2), but the carcinogenic role of these mutations is unclear. Here we describe a mouse model in which the most common somatic Ezh2 gain-of-function mutation (EZH2(Y646F) in human; Ezh2(Y641F) in mouse) is conditionally expressed. Expression of Ezh2(Y641F) in mouse B cells or melanocytes caused high-penetrance lymphoma or melanoma, respectively. Overexpression of the anti-apoptotic protein Bcl2, but not the oncoprotein Myc, or loss of the tumor suppressor protein p53 (encoded by Trp53 in mice) further accelerated lymphoma progression. Expression of the mutant Braf but not the mutant Nras oncoprotein further accelerated melanoma progression. Although expression of Ezh2(Y641F) globally increased the abundance of trimethylated Lys27 of histone H3 (H3K27me3), it also caused a widespread redistribution of this repressive mark, including a loss of H3K27me3 that was associated with increased transcription at many loci. These results suggest that Ezh2(Y641F) induces lymphoma and melanoma through a vast reorganization of chromatin structure, inducing both repression and activation of polycomb-regulated loci.

Aging in mammals is the gradual decline of an organism's physical, mental, and physiological capacity. Aging leads to increased risk for disease and eventually to death. Here, we show that Brd2 haploinsufficiency (Brd2+/-) extends lifespan and increases healthspan in C57B6/J mice. In Brd2+/- mice, longevity is increased by 23% (p

Despite novel therapies for melanoma, drug resistance remains a significant hurdle to achieving optimal responses. NRAS‐mutant melanoma is an archetype of therapeutic challenges in the field, which we used to test drug combinations to avert drug resistance. We show that BET proteins are overexpressed in NRAS‐mutant melanoma and that high levels of the BET family member BRD4 are associated with poor patient survival. Combining BET and MEK inhibitors synergistically curbed the growth of NRAS‐mutant melanoma and prolonged the survival of mice bearing tumors refractory to MAPK inhibitors and immunotherapy. Transcriptomic and proteomic analysis revealed that combining BET and MEK inhibitors mitigates a MAPK and checkpoint inhibitor resistance transcriptional signature, downregulates the transcription factor TCF19, and induces apoptosis. Our studies demonstrate that co‐targeting MEK and BET can offset therapy resistance, offering a salvage strategy for melanomas with no other therapeutic options, and possibly other treatment‐resistant tumor types.

Multiple myeloma (MM) is a disease of aging adults and autologous stem cell transplant (ASCT) is considered the standard of care. As the population ages a growing number of older adults will undergo ASCT and an objective approach to estimate physiologic reserve and transplant morbidity risk is warranted. Here, we evaluate assess p16INK4a (p16), a molecular aging biomarker, along with geriatric metrics to determine risk of transplant toxicity. Methods We prospectively evaluated 100 MM patients for frailty before and after ASCT using a Geriatric Assessment (GA) and collected T-cells for analysis of p16 using a custom nanostring codeset. Results Pre-transplant physical function was predicative of hospital length of stay (LOS). Each one-unit increase in physical function score, the average LOS decreased by 0.52 days (95% CI, −1.03–0.02); p = .04). Similarly, higher self-report of ADL/IADL (Human Activity Profile was associated with shorter LOS (0.65 less days (95% CI −1.15 to −0.15), p = .01). Patients with anxiety/depression (OR = 1.10 (95% CI 1.00–1.22), p = .056), lower handgrip strength (OR = 0.90 (95% CI 0.82–0.98), p = .02), falls (OR = 1.60 (95% CI 1.07–2.38), p = .02), or weight loss (OR = 5.65 (95% CI 1.17–25.24), p = .03) were more likely to be re-admitted. The estimated EFS at 1-year was 85% (95% CI, 75–91) with median follow-up of 15.7 months. Weight loss was a significant predictor of EFS (HR = 3.13 (95% CI 1.15–8.50), p = .03). Frailty assessment by self-reported fatigue minimally correlated with T-cell p16 expression (r = 0.28; p = .02). Age, Karnofsky Performance Status (KPS), or Hematopoietic cell transplantation-specific Co-Morbidity Index (HCT-CI) did not predict hospital LOS or readmissions. Conclusions Our data illustrate that a GA can identify individuals with MM who are at greater risk for morbidity following ASCT.

Senescent cells accumulate with age in vertebrates and promote aging largely through their senescence‐associated secretory phenotype (SASP). Many types of stress induce senescence, including genotoxic stress. ERCC1‐XPF is a DNA repair endonuclease required for multiple DNA repair mechanisms that protect the nuclear genome. Humans or mice with reduced expression of this enzyme age rapidly due to increased levels of spontaneous, genotoxic stress. Here, we asked whether this corresponds to an increased level of senescent cells. p16Ink4a and p21Cip1 mRNA were increased ~15‐fold in peripheral lymphocytes from 4‐ to 5‐month‐old Ercc1 −/∆ and 2.5‐year‐old wild‐type (WT) mice, suggesting that these animals exhibit a similar biological age. p16Ink4a and p21Cip1 mRNA were elevated in 10 of 13 tissues analyzed from 4‐ to 5‐month‐old Ercc1 −/∆ mice, indicating where endogenous DNA damage drives senescence in vivo. Aged WT mice had similar increases of p16Ink4a and p21Cip1 mRNA in the same 10 tissues as the mutant mice. Senescence‐associated β–galactosidase activity and p21Cip1 protein also were increased in tissues of the progeroid and aged mice, while Lamin B1 mRNA and protein levels were diminished. In Ercc1 −/Δ mice with a p16Ink4a luciferase reporter, bioluminescence rose steadily with age, particularly in lung, thymus, and pancreas. These data illustrate where senescence occurs with natural and accelerated aging in mice and the relative extent of senescence among tissues. Interestingly, senescence was greater in male mice until the end of life. The similarities between Ercc1 −/∆ and aged WT mice support the conclusion that the DNA repair‐deficient mice accurately model the age‐related accumulation of senescent cells, albeit six‐times faster., Senescent cells contribute to aging and its associated morbidities. Senescent cells accumulate in vertebrates with aging. Here, we survey where (in what tissues) senescence occurs with aging in mice, by measuring p16Ink4a and p21Cip1 mRNA. A similar survey in Ercc1 −/Δ mice illustrates where (in what tissues) senescence occurs in vivo as a consequence of endogenous DNA damage.

NRAS mutation at codons 12, 13, or 61 is associated with transformation; yet, in melanoma, such alterations are nearly exclusive to codon 61. Here, we compared the melanoma susceptibility of an NrasQ61R knock-in allele to similarly designed KrasG12D and NrasG12D alleles. With concomitant p16INK4a inactivation, KrasG12D or NrasQ61R expression efficiently promoted melanoma in vivo, whereas NrasG12D did not. In addition, NrasQ61R mutation potently cooperated with Lkb1/Stk11 loss to induce highly metastatic disease. Functional comparisons of NrasQ61R and NrasG12D revealed little difference in the ability of these proteins to engage PI3K or RAF. Instead, NrasQ61R showed enhanced nucleotide binding, decreased intrinsic GTPase activity, and increased stability when compared with NrasG12D. This work identifies a faithful model of human NRAS-mutant melanoma, and suggests that the increased melanomagenecity of NrasQ61R over NrasG12D is due to heightened abundance of the active, GTP-bound form rather than differences in the engagement of downstream effector pathways. Significance: This work explains the curious predominance in human melanoma of mutations of codon 61 of NRAS over other oncogenic NRAS mutations. Using conditional “knock-in” mouse models, we show that physiologic expression of NRASQ61R, but not NRASG12D, drives melanoma formation. Cancer Discov; 4(12); 1418–29. ©2014 AACR. This article is highlighted in the In This Issue feature, p. 1355

Background: Multiple Myeloma (MM) is associated with T-cell dysfunction. MM-related T-cell deficiencies are reported as both quantitative and qualitative defects with variable functional abnormalities. The clinical significance of these T-cell abnormalities in MM is not fully characterized. Furthermore, the impact of Autologous Stem Cell Transplant (ASCT) on T-cell subsets and immune checkpoint molecules, including PD-L1, PD-1, BLIMP-1, CTLA-4/CD28, TIM-3, and LAG-3, is being explored. Here we examined these features along with other mRNA markers of cellular senescence, immunosenescence, and exhaustion in MM patients pre- and post-ASCT. These studies aimed to improve understanding of the immunologic changes in MM and relationship to disease progression. Evaluating T-cell immune reconstitution post-transplant is invaluable for future therapies to identify targets or stimulate T-cell response to mitigate relapse. Methods: 100 MM patients were prospectively enrolled in a longitudinal study prior to ASCT for analysis of clinical and biologic factors related to clinical outcomes and event free survival (EFS) post-transplant. Paired peripheral blood T-cells (PBTL) were analyzed (n=31) before ASCT and 90 days post-ASCT. PBTL mRNA targets were anayzed using a custom Nanostring platform (OSU_Senescence) evaluating markers of cellular senescence, immunosenescence, and exhaustion. T-cell populations and subsets were further characterized by flow cytometry pre- and post-ASCT in 20 representative trial patients and 10 age- and sex-matched controls. Serum samples were analyzed for soluble ligands using Luminix MAGPIX multiplex analysis. Results: Increased PBTL LAG-3 mRNA expression at 90 days post-ASCT was significantly associated with EFS, HR 5.44 (95%CI 1.92-15.46, p=0.001, adjusted p* controlling for false discovery rate=0.038). When adjusted for age, a similar relationship of increased PBTL LAG-3 mRNA expression and EFS was found, HR 5.66 (95%CI 1.83-17.47, p=0.003, p*=0.056). No relationship was observed between other mRNA markers of immunosenesence or exhaustion and EFS. Flow cytometric analysis of post-transplant PBTLs revealed an inverted CD4:CD8 ratio, reduced CD28 expression on CD8+ T-cells, and increased levels of CD4+ T-regulatory cells. LAG-3 expression was significantly increased in CD4+ T-cells post-ASCT, predominately in the CD4 naïve and central memory subsets. Soluble LAG-3 (sLAG3) serum concentrations were similar pre- and post-ASCT, and in comparison to controls. Conclusions: We found increased expression of Lymphocyte-Activation Gene, LAG-3 (CD223), on CD4+T-cells post-ASCT. PBTL LAG-3 mRNA expression 90 days post-ASCT was associated with EFS and may serve as an early indicator of adverse outcomes. LAG-3 is expressed on activated T-cells and modulates T-cell expansion and function. Future studies targeting the LAG-3 pathway are warranted to restore T-cell dysfunction and augment immunity in MM. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Multiple myeloma (MM) is an incurable hematologic malignancy diagnosed primarily in older adults. As the population ages, myeloma incidence is expected to increase at a higher rate than many other malignancies.1 Approved chemotherapy and targeted regimens for older adults with MM are numerous and exhibit distinct toxicities. The physiological heterogeneity of older adults makes it challenging for physicians to identify the most effective, yet best tolerated regimen, for each MM patient. As such, use of a two-drug regimen, three-drug regimen, or intensive autologous hematopoietic stem cell transplant (AHSCT) is often subjective. Consequently, AHSCT eligibility is subjectively applied and more objective measures are warranted to better understand health status in older adults. We believe that objective markers of physiological age will improve treatment stratification and will be an additional tool in understanding how treatment and transplant have an impact on health status.

Monitoring cancer and aging in vivo remains experimentally challenging. Here, we describe a luciferase knockin mouse (p16(LUC)), which faithfully reports expression of p16(INK4a), a tumor suppressor and aging biomarker. Lifelong assessment of luminescence in p16(+/LUC) mice revealed an exponential increase with aging, which was highly variable in a cohort of contemporaneously housed, syngeneic mice. Expression of p16(INK4a) with aging did not predict cancer development, suggesting that the accumulation of senescent cells is not a principal determinant of cancer-related death. In 14 of 14 tested tumor models, expression of p16(LUC) was focally activated by early neoplastic events, enabling visualization of tumors with sensitivity exceeding other imaging modalities. Activation of p16(INK4a) was noted in the emerging neoplasm and surrounding stromal cells. This work suggests that p16(INK4a) activation is a characteristic of all emerging cancers, making the p16(LUC) allele a sensitive, unbiased reporter of neoplastic transformation.

Selinexor, a selective inhibitor of nuclear export (SINE) compound targeting exportin-1, has previously been shown to inhibit melanoma cell growth in vivo. We hypothesized that combining selinexor with antibodies that block or disrupt T-cell checkpoint molecule signaling would exert superior antimelanoma activity. In vitro, selinexor increased PDCD1 and CTLA4 gene expression in leukocytes and induced CD274 gene expression in human melanoma cell lines. Mice bearing syngeneic B16F10 melanoma tumors demonstrated a significant reduction in tumor growth rate in response to the combination of selinexor and anti-PD-1 or anti-PD-L1 antibodies (P < 0.05). Similar results were obtained in B16F10-bearing mice treated with selinexor combined with anti-CTLA4 antibody. Immunophenotypic analysis of splenocytes by flow cytometry revealed that selinexor alone or in combination with anti-PD-L1 antibody significantly increased the frequency of both natural killer cells (P ≤ 0.050) and CD4+ T cells with a Th1 phenotype (P ≤ 0.050). Further experiments indicated that the antitumor effect of selinexor in combination with anti-PD-1 therapy persisted under an alternative dosing schedule but was lost when selinexor was administered daily. These data indicate that the efficacy of selinexor against melanoma may be enhanced by disrupting immune checkpoint activity. Mol Cancer Ther; 16(3); 417–27. ©2017 AACR. See related article by Tyler et al., p. 428.

e21578Background: Senescence is an irreversible cell cycle arrest associated with sustained p16INK4a (p16) expression and biological aging. The inability of senescent cells to proliferate suggests ...

Expression of the p16(INK4a) tumor suppressor sharply increases with age in most mammalian tissues, and contributes to an age-induced functional decline of certain self-renewing compartments. These observations have suggested that p16(INK4a) expression could be a biomarker of mammalian aging. To translate this notion to human use, we determined p16(INK4a) expression in cellular fractions of human whole blood, and found highest expression in peripheral blood T-lymphocytes (PBTL). We then measured INK4/ARF transcript expression in PBTL from two independent cohorts of healthy humans (170 donors total), and analyzed their relationship with donor characteristics. Expression of p16(INK4a), but not other INK4/ARF transcripts, appeared to exponentially increase with donor chronologic age. Importantly, p16(INK4a) expression did not independently correlate with gender or body-mass index, but was significantly associated with tobacco use and physical inactivity. In addition, p16(INK4a) expression was associated with plasma interleukin-6 concentration, a marker of human frailty. These data suggest that p16(INK4a) expression in PBTL is an easily measured, peripheral blood biomarker of molecular age.

The Kaposi's sarcoma-associated herpesvirus (KSHV/HHV8) is associated with Kaposi's sarcoma (KS) as well as primary effusion lymphomas (PEL). The expression of viral proteins capable of inactivating the p53 tumor suppressor protein has been implicated in KSHV oncogenesis. However, DNA-damaging drugs such as doxorubicin are clinically efficacious against PEL and KS, suggesting that p53 signaling remains intact despite the presence of KSHV. To investigate the functionality of p53 in PEL, we examined the response of a large number of PEL cell lines to doxorubicin. Two out of seven (29%) PEL cell lines harbored a mutant p53 allele (BCBL-1 and BCP-1) which led to doxorubicin resistance. In contrast, all other PEL containing wild-type p53 showed DNA damage-induced cell cycle arrest, p53 phosphorylation, and p53 target gene activation. These data imply that p53-mediated DNA damage signaling was intact. Supporting this finding, chemical inhibition of p53 signaling in PEL led to doxorubicin resistance, and chemical activation of p53 by the Hdm2 antagonist Nutlin-3 led to unimpaired induction of p53 target genes as well as growth inhibition and apoptosis.

Cyclin D1 is a multifaceted regulator of both transcription and cell-cycle progression that exists in two distinct isoforms, cyclin D1a and D1b. In the prostate, cyclin D1a acts through discrete mechanisms to negatively regulate androgen receptor (AR) activity and thus limit androgen-dependent proliferation. Accordingly, cyclin D1a is rarely overexpressed in prostatic adenocarcinoma and holds little prognostic value in this tumor type. However, a common polymorphism (A870) known to facilitate production of cyclin D1b is associated with increased prostate cancer risk. Here we show that cyclin D1b is expressed at high frequency in prostate cancer and is up-regulated in neoplastic disease. Furthermore, our data demonstrate that, although cyclin D1b retains AR association, it is selectively compromised for AR regulation. The altered ability of cyclin D1b to regulate the AR was observed by using both in vitro and in vivo assays and was associated with compromised regulation of AR-dependent proliferation. Consistent with previous reports, expression of cyclin D1a inhibited cell-cycle progression in AR-dependent prostate cancer cells. Strikingly, cyclin D1b significantly stimulated proliferation in this cell type. AR-negative prostate cancer cells were nonresponsive to cyclin D1 (a or b) expression, indicating that defects in AR corepressor function yield a growth advantage specifically in AR-dependent cells. In summary, these studies indicate that the altered AR regulatory capacity of cyclin D1b contributes to its association with increased prostate cancer risk and provide evidence of cyclin D1b-mediated transcriptional regulation.

Somatic sequencing of cancers has produced new insight into tumorigenesis, tumor heterogeneity, and disease progression, but the vast majority of genetic events identified are of indeterminate clinical significance. Here, we describe a NextGen sequencing approach to fully analyzing 248 genes, including all those of known clinical significance in melanoma. This strategy features solution capture of DNA followed by multiplexed, high-throughput sequencing and was evaluated in 31 melanoma cell lines and 18 tumor tissues from patients with metastatic melanoma. Mutations in melanoma cell lines correlated with their sensitivity to corresponding small molecule inhibitors, confirming, for example, lapatinib sensitivity in ERBB4 mutant lines and identifying a novel activating mutation of BRAF. The latter event would not have been identified by clinical sequencing and was associated with responsiveness to a BRAF kinase inhibitor. This approach identified focal copy number changes of PTEN not found by standard methods, such as comparative genomic hybridization (CGH). Actionable mutations were found in 89% of the tumor tissues analyzed, 56% of which would not be identified by standard-of-care approaches. This work shows that targeted sequencing is an attractive approach for clinical use in melanoma.

Previous research has shown that relatively localized acoustic information, such as voice pitch, f0 perturbation, and hoarseness are cues to age perception. The present studies examined the potential role of sentence‐level prosodic information in the perception of age. Sixteen different six‐word sentences were recorded from eight different males in each of three age groups (middle school students, college students, and senior citizens). Several acoustic measurements were made of each sentence, including mean frequency, slope of intonation contour across entire sentence, slope of terminal fall, and amount of inflection (i.e., absolute frequency change summed across the sentence). A second set of sentences was constructed by randomly reordering the words in each sentence. Original sentences and their scrambled counterparts were presented to 19 listeners who rated the age in years of the speaker of each sentence. Analyses of variance revealed that age judgments were less extreme for scrambled sentences as co...

Of the four molecular subtypes of melanoma (BRAF, NRAS, NF1, and triple WT), NRAS mutant tumors are notoriously more aggressive and challenging to treat. The frequent occurrence of NRAS mutations in benign, congenital nevi suggests that these genetic alterations are early events in melanoma genesis. Since NRAS mutant nevi can remain indolent for years, or even a lifetime, secondary genetic events must be required to drive melanoma initiation. Ultraviolet (UV) light, a major risk factor for melanoma, is known to directly damage DNA and alter the skin microenvironment. Therefore, we hypothesized that the cell-extrinsic and intrinsic events triggered by UV exposure would cooperate with NrasQ61R mutations to drive melanoma formation in vivo. To test this hypothesis we employed a genetically engineered mouse model (i.e. TpN61R) that combines CRE-inducible expression of NrasQ61R with the loss of p16INK4a in melanocytes. Following neonatal CRE induction, we exposed TpN61R mice to a single, nonerythemic dose of UVB radiation and monitored them for the development of melanoma. Exposure to UVB radiation dramatically reduced the melanoma-free survival of TpN61R mice by 80% and increased tumor multiplicity (average 1.2 to 3.4 tumors/mouse); however, it had no impact on tumor growth rates, overall skin proliferation, immune infiltration, or vascularity. To test the respective roles of NrasQ61R and p16INK4a loss in UV-induced melanoma genesis, we generated mice with either melanocytic NrasQ61R expression or p16INK4a loss. Mice with p16INK4a loss alone did not develop tumors in the presence or absence of UV. By contrast, in UV treated TN61R mice, NrasQ61R was sufficient to initiate melanoma formation, albeit with a 66% longer latency than UV exposed TpN61R animals (9.14wks vs. 5.5wks). To determine if NrasQ61R mutations had to be present at the time of UV exposure to drive early melanoma formation, TpN61R mice were exposed to UV prior to CRE activation. Even when NrasQ61R expression was induced three days after UV exposure, melanoma formation was rapidly accelerated. Therefore, NRAS mutations do not need to be present at time of UV exposure to promote early melanoma formation. Genomic analyses comparing spontaneous and UV-induced TpN61R melanomas failed to uncover common secondary mutations that explain the exquisite cooperativity between NrasQ61R and UV light in driving melanoma formation. For this reason, we sought to identify UV-induced, cell-extrinsic factors that might facilitate the initiation of NrasQ61R mutant melanomas via cytokine profiling. Through these analyses we identified UV-induced pro-inflammatory cytokines that could be therapeutically targeted to limit the initiation of NRAS-mutant melanomas. Together, this work explains why UV exposure is such a significant risk factor for melanoma and provides original mechanistic insight into how this deadly disease might be prevented. Citation Format: Rebecca C. Hennessey, Andrea M. Holderbaum, James E. Gillahan, Conor Delaney, Xing Tang, Raleigh Kladney, Christin E. Burd. Ultraviolet light cooperates with NrasQ61R mutations to drive malignant melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2685.

Cellular senescence, a process in which cells permanently exit the cell cycle, has pleiotropic biological effects. Several lines of evidence suggest that senescent cells within the tumor microenvironment can elicit a pro-inflammatory secretome that promotes cancer initiation and progression. This proinflammatory phenotype differs amongst senescent cells triggered by distinct stimuli; therefore, multiple forms of senescent cells likely exist within the tumor stroma during cancer evolution and treatment. Here, we sought to determine how stromal senescence initiated by clinically relevant treatments would influence melanoma growth. To generate senescent stromal populations, we treated presenescent MEFs (p4) with ultraviolet light (UV), Mitomycin C (MMC), or a CDK4/6 inhibitor (CDK4/6i). In contrast to p4 fibroblasts, cells treated with UV, MMC or CDK4/6i exhibited cell cycle arrest, increased SA-β-gal positivity and elevated p16INK4a expression. Pronounced 53BP1 and γH2AX foci were only observed in the UV and MMC treated cells, suggesting the CDK4/6i treatment did not induce DNA damage. Profiling of gene expression using a TaqMan mouse inflammation expression panel revealed distinctions amongst the 4 fibroblast lines. Of the senescent cell populations, CDK4/6i fibroblasts showed the highest number of elevated pro-inflammatory transcripts. To define the in vitro paracrine growth effects induced by stromal senescence, melanoma cell lines harboring either Braf600E, Ras, or unknown (wild-type) driver were co-cultured with each fibroblast population. In general, melanoma cells grew similarly on senescent and non-senescent fibroblasts; however, tumor cell growth was genotype-dependent. Notably, CDK4/6i fibroblasts never stimulated additional tumor cell growth in vitro. In contrast, syngeneic transplantations of fibroblasts and tumor cells into immune competent mice revealed that all senescent fibroblasts stimulated tumor growth in vivo. However, whether senescent and non-senescent fibroblasts promoted tumor growth at the same rate was genotype-dependent. Since this is the first study to examine the paracrine effects of senescent stromal cells using an immune competent mouse, we performed IHC for CD45 to assess whether immune cell recruitment differs in the presence of senescent stromal fibroblasts. No increase in CD45 positive infiltrates was observed in the melanoma lines co-injected with CDK4/6i fibroblasts. Together, this work reveals that melanoma growth in response to senescent stromal fibroblasts is genotype dependent, and that this stromal promotion of cancer growth can be accurately assessed only in the context of an immune competent, syngeneic host. Moreover, these data suggest that stromal senescence induced by emerging CDK4/6 inhibitor therapies and/or regimens combining chemotherapy/radiation with immune checkpoint blockade may also promote tumor growth through the paracrine effects of senescent bystanders. Citation Format: Xiangnan Guan, Kyle Lapak, Rebecca Hennessey, Christin Burd. PD0332991-induced stromal senescence promotes melanoma growth in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2827.

Cutaneous melanoma claims the life of one American every hour, and while the etiology of this tumor type is not entirely understood, exposure to ultraviolet (UV) radiation (280-340nm) is a major risk factor. For this reason, the use of UV-blocking sunscreens is strongly advocated; however, few studies have tested the relative efficacy of these agents in preventing melanoma formation in vivo. Here, we employed a new genetically engineered mouse model (TpN61R) to examine the ability of 6 chemically distinct SPF30 sunscreens to prevent melanoma. In this TpN61R model, topical 4-hydroxytamoxifen (4OHT) treatment induces the melanocyte-specific expression of oncogenic NRas as well as inactivation of the p16INK4a tumor suppressor. These genetic lesions co-occur in ∼24% of all human melanomas, making the TpN61R model biologically relevant. Since NRAS mutations are an early and UV-independent event in human melanoma, TpN61R mice were first painted with 4OHT and then exposed to a single dose of 4.5 kJ/m2 UVB light one day later. Exposed skin from TpN61R mice showed transient cyclobutane pyrimidine dimer (CPD) formation, however no evidence of edema or inflammation was observed. Despite these mild effects, UVB exposure reduced the melanoma-free survival of TpN61R mice by 80% and increased tumor incidence rate from 1.2 to 3.4 tumors/mouse. Further experiments using a variety of UVB doses (0.25, 1.0, 2.3 and 9.0 kJ/m2) in the TpN61R model revealed a dose-dependent increase in early melanoma incidence. Together, these data establish the exquisite cooperation of UV light and oncogenic NRas mutations in driving melanoma. Taking advantage of this unique model, we tested the preventative efficacy of SPF30 sunscreens with differing chemical composition. Sunscreens components included UVA (avobenzene), UVB (homosalate, octisalate) and broad spectrum (oxybenzone, octocrylene, zinc oxide) blocking agents. Application of sunscreen prior to UVB exposure decreased DNA damage, delayed melanoma onset and reduced tumor incidence in a sunscreen-dependent manner. Thus, SPF30 sunscreens do not equally prevent UVB-induced, NRAS mutant melanoma. This work establishes the first in vivo system to test sunscreen efficacy in NRAS-driven melanoma and will help direct the development of improved melanoma preventatives. Citation Format: Andrea M. Holderbaum, Rebecca C. Hennessey, James E. Gillahan, Anamaria Bonilla, Conor Delaney, Raleigh D. Kladney, Kathleen L. Tober, Tatiana M. Oberyszyn, Christin E. Burd. In vivo modeling of NRAS-mutant melanoma reveals differential preventative efficacy amongst SPF30 sunscreens. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 900.

Melanoma mortality is directly linked to its profoundly metastatic nature and inherent resistance to conventional chemotherapy. For this reason, increased understanding of the molecular mechanisms driving melanoma progression is of utmost importance. The p21-activated serine/threonine kinases (PAKs) are frequently mutated or overexpressed in cancer and have recently been implicated in tumor metastasis, proliferation, and apoptotic resistance. This observation has inspired drug discovery efforts to limit PAK activity; yet, mechanistic understanding of how PAKs (especially Type II PAKs) contribute to tumor initiation and progression is still evolving. PAK7, a type II PAK, is mutated in 16-18% of all melanomas. Melanoma-associated PAK7 mutations occur throughout the gene and have unknown biochemical and physiological consequences. The objective of this study was to determine how tumor-associated PAK7 variants mechanistically contribute to melanoma initiation and progression. First, we characterized PAK7 protein expression in a panel of 39 melanoma cell lines and primary melanocyte cultures. PAK7 levels were similar in both tumorigenic and non-tumorigenic cells and failed to correlate with the status of common melanoma driver mutations (e.g. NRASQ61, BRAFV600). In an array of 101 human tumor biopsies, PAK7 expression did not significantly change with advancing melanoma stage; however, PAK7 levels were higher in regional lymph node biopsies when compared to primary skin lesions. Since mutation is the predominant mechanism affecting PAK7 in melanoma, we investigated the biochemical and physiological consequences of common PAK7 variants. 11 distinct PAK7 mutations were stably expressed at low levels in VMM39 (melanoma) and NCI-H441 (lung) cells. Using these clones, changes in the phosphorylation of downstream PAK7 targets associated with cellular migration (p120), proliferation (CRAF), and apoptotic resistance (BAD, MDM2) were examined. In addition, we defined phenotypic alterations in cellular morphology, proliferation, migration, and apoptotic resistance associated with the expression of each mutant. These data allowed us to classify PAK7 variants of unknown significance into groups associated with specific cellular outcomes. To our knowledge, this is the first study to functionally characterize a wide variety of melanoma-associated PAK7 mutations and represents a critical first step in understanding how this kinase contributes to tumor initiation and progression. Citation Format: Kyle M. LaPak, Michael A. Gross, Denny C. Vroom, Greg B. Lesinski, William E. Carson. Defining the role of PAK7 variants in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 195.

A geriatric assessment (GA) is a global approach to improve healthy aging, wherein occult problems are assessed and intervened upon using a multidisciplinary method. A GA is feasible and can predict chemotherapy-induced toxicity and overall survival in cancer patients. Biomarkers of aging are also being explored as objective and reproducible measures of health and fitness. p16INK4a (p16) is a marker of cellular senescence that rises exponentially with chronologic age and is influenced by factors such as physical activity, smoking, and solid tumor chemotherapy. Here, we investigated the relationship of both the GA and molecular (i.e. p16) metrics in pre-bone marrow transplant (BMT) multiple myeloma (MM) patients. We selected this group for our studies as BMT patients are a vulnerable cohort in which transplant eligibility is subjective and age related. BMT patients are also at high risk for adverse events and treatment toxicity. In this preliminary analysis, we explored the predictive value of GA metrics and p16 with inpatient length of stay (LOS) during autologous BMT. Methods: We performed a pilot prospective cohort study on 55 MM patients during their pre-transplant evaluation. MM patients >18 years completed GA assessments related to physical function, distress, comorbidities, social support, and cognition. Patients completed surveys using the Brief Fatigue Inventory (BFI) (scale 1-10; moderate fatigue 4-6, severe fatigue 7+); Hospital Anxiety and Depression (HADS) (borderline case 8-10, definite case 11+); medical outcome study-social support survey (MOS-SSS) (scale 0-100, higher scores indicated greater support), Human Activity Profile (HAP) maximum activity score (MAS) and HAP-adjusted activity score (AAS), a 94-item questionnaire ranking tasks according to energy use validated in the BMT population, with higher scores indicating higher activity (Herzberg BBMT 2010). Objective measures of physical activity were measured using the Short Physical Performance Battery (SPPB) (range 0-12; impairment Results: The median patient age was 61 (range 42-76). Most patients exhibited early stage disease (ISS Stage 1 53%) with minimal comorbidities (HCT-CI median 1; range 0-8) and a median of 2 prior lines of treatment (range 1-11). Pre-transplant Karnofsky Performance Status (KPS) was reported as 70% (n=10), 80% (n=10), 90% (n=15) and 100% (n=12). 7 patients did not proceed with BMT, 1 inpatient for BMT. Patients reported moderate fatigue by BFI (median 4.3; range 0-9.8), with minimal anxiety or depression as measured by the HADS. Self-reported physical activity by HAP-MAS was 73 (range 30-94) and HAP-AAS was 64 (range 20-94). Patients reported high levels of social support (median 86.7%; range 18.2-100) by MOS-SSS. Objective measures of physical function were also high as measured by the SPPB (median 10; range 4-12) and no cognitive impairment was identified by the 3MS. p16 expression was adjusted for age and did not correlate with GA tools including BFI, HADS, HAP-AAS, HAP-MAS, MOS-SSS, SPPB or 3MS. The median length LOS during transplant was 16 days (range 12-36). Univariate analysis revealed that SPPB score was significantly associated with LOS, where each one unit increase in physical performance corresponded to an average LOS decrease of 0.63 days (p=0.04). Self-reported activity by HAP-AAS also correlated with LOS (p=0.05). LOS was not influenced by p16, age, KPS or HCT-CI. Age and HCT-CI had no relationship with SPPB scores, but KPS did (p=0.03727). Conclusions: A comprehensive GA can be used to identify factors that contribute to BMT outcomes. Physical function appears to be most predictive of hospital LOS as measured by SPPB or a detailed self-report of physical function. Baseline p16 levels had no relationship with GA metrics in this selected population. A standardized approach for determining patient fitness including SPPB and HAP-AAS assessments may improve treatment tolerance, reduce hospital LOS, and decrease the risk for adverse outcomes in BMT populations. Disclosures Jaglowski: Immunomedics: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Seattle Genetics: Consultancy.

Immunotherapy and immune-based anti-cancer molecules represent a valid strategy to fight cancer. However, the choice of tumor-specific surface molecules for the selective targeting of cancer cells still represents a critical step in the study design for the development of new therapeutic approaches. Notably, the development of phage-display technology for the selection of fully human single chain antibody fragments (scFvs) and complete antibodies directed toward tumor-associated antigens has represented a significant advancement for immunotherapy. Nucleolin (NCL) is one of the most abundant non-ribosomal proteins in the nucleolus. NCL is frequently up-regulated in cancer and in cancer-associated endothelial cells compared to normal tissues, where it is also present on the cell surface. Altered NCL expression and localization results in oncogenic effects such as stabilization of oncogenic mRNAs and microRNAs (miRNAs). Particularly, we demonstrated that NCL enhances the maturation of specific miRNAs (including miR-21, miR-221 and miR-222) causally involved in cancer pathogenesis, aggressiveness, metastatic potential and resistance to several anti-neoplastic treatments. Because of its oncogenic role and specific expression on cancer cell surface, NCL represents an attractive target for anti-neoplastic therapies. To produce a new anti-NCL molecule with significant potential for clinical applications, we took advantage of phage-display technology to isolate a fully human single chain Fragment variable (scFv), named 4LB5, which binds with high affinity to the RNA binding domain (RBD) of NCL. In our previous study we demonstrated that 4LB5 binds NCL on the surface of aggressive breast cancer cells and inhibits their proliferation both in vitro and in vivo, representing the prototype of a new class of immune-based anti-NCL compounds. Since NCL expression has been previously reported on the cell surface of skin cancer cell lines and up-regulation of NCL-dependent microRNAs was described in human melanomas, the objective of this project was the assessment of 4LB5 as a potential tool for melanoma therapy. To this aim, the recombinant scFv was expressed as His6-fusion protein in E.Coli and purified by affinity chromatography, as previously described. By using Enzyme-Linked Immunosorbent Assays (ELISA), we demonstrated a significant binding of 4LB5 to the cell surface of different melanoma cell lines of both human and mouse origins. Notably, inhibition of NCL expression by siRNA transfection reduced the binding of 4LB5 to the cell surface of these cell lines, further supporting its specificity against NCL. Then, we assessed the potential effects of 4LB5 treatment on cell proliferation. Colony formation assays demonstrated that 4LB5 significantly affected cell proliferation of both human and mouse melanoma cell lines. Our results, in agreement with previously reported data, further support the potential activity of 4LB5 as a tool for cancer therapy, paving the way for additional investigations aimed to fully elucidate the molecular mechanisms affected by this scFv and resulting in its anti-neoplastic therapy in human melanomas. Furthermore, this study supports the idea that anti-NCL immunoagents might represent a class of new anti-cancer compounds with a strong clinical relevance for a wide range of human tumors. Citation Format: Ashley Braddom, Timothy Richmond, Tyler Sheetz, Erika Reese, Anna Tessari, Kathleen Tober, Christin E. Burd, Claudia De Lorenzo, Edward W. Martin, Jr., Vincenzo Coppola, Michael F. Tweedle, Tatiana Oberyszyn, Carlo M. Croce, Dario Palmieri. Human anti-Nucleolin recombinant immunoagents as new potential tools for melanoma treatment. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C171.

Exportin-1 (XPO1) is a nuclear export protein with >220 cargo proteins, including tumor suppressors and cell cycle modulators. Selinexor is a SINE (Selective Inhibitor of Nuclear Export) compound that has been administered to >900 cancer patients in Phase I and II trials to date, with evidence of efficacy and tolerability. Selinexor blocks nuclear export of NFAT1c, STAT1 and STAT3, which are implicated in regulating the inhibitory T cell receptor PD-1 and its ligand, PD-L1. We hypothesized that selinexor would upregulate T cell checkpoint molecule expression, and that combination treatment with anti-PD-1 or anti-PD-L1 would thereby enhance the ability of selinexor to elicit antitumor activity. Selinexor increased PD-1 gene expression by ~2-fold in normal lymphocytes and induced PD-L1 gene expression in tumor cell lines. Mice bearing syngeneic colon tumors (colon26) treated with selinexor and anti-PD-1 for 2 weeks demonstrated a significant reduction in tumor growth rate (P < 0.05), while monotherapy with either agent had no significant effect on tumor growth. Similar results were obtained in mice bearing syngeneic B16F10 melanoma tumors, whereby combined treatment with selinexor + anti-PD-1 was superior to either single agent alone (p < 0.034). Combined therapy of mice bearing B16F10 tumors with selinexor and anti-PD-L1 was similarly effective, with significantly smaller tumors at the study endpoint (p < 0.001). No weight loss or signs of toxicity were evident in any in vivo study. Immunophenotypic analysis by flow cytometry revealed that selinexor alone or in combination with anti-PD-1/anti-PD-L1 significantly increased the percentage of splenic NK cells (p≤0.050), while selinexor ± anti-PD-L1 significantly increased the percentage of splenic Th1 T cells (p≤0.011), all compared to vehicle treated mice. Interestingly, combining selinexor with anti-PD-L1 significantly decreased the percentage of splenocytes that expressed PD-L1 (p < 0.001). These data indicate that the efficacy of selinexor may be enhanced by disrupting the pre-existing PD-1/PD-L1 signaling in effector cells (T and NK cells). Altogether, these data suggest that the efficacy of selinexor in combination with anti-PD-1 or anti PD L1 in mouse syngeneic tumor models may be due to both disrupting immunosuppressive PD-1/PD-L1 signaling and increasing the frequency of potentially tumor reactive NK cells and Th1 T cells. This provides a rational basis for this treatment combination as a novel therapeutic approach for advanced cancer.

The effect of trait neuroticism on college students' (n=200) responses to anti-smoking public service announcements (PSAs) was examined using a 2 (neuroticism: high vs. low) × 3 (message type: personal testimony, secondhand smoke, and informative) × 3 (message: nested within message type) design. We hypothesized that those high in neuroticism would be avoidant toward anti-smoking messages, have quicker and stronger negative reactions and perceive the messages as more biased and less involving. As hypothesized, those high in neuroticism were more likely to want to avoid thinking about smoking as a function of viewing the messages and more likely to see messages as biased; however, neuroticism did not affect judgments of message involvement. Tobacco use and gender also affected message bias and avoidance. Those scoring high in neuroticism also responded quicker to negative emotion assessments to messages. Implications for the importance of neuroticism in message design and message processing research are discussed.

The role of p53 in primary effusion lymphoma (PEL) is complicated. The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) binds p53. Despite this interaction, we had found that p53 was functional in PEL, i.e., able to induce apoptosis in response to DNA damage (C. E. Petre, S. H. Sin, and D. P. Dittmer, J. Virol. 81:1912-1922, 2007), and that hdm2 was overexpressed. To further elucidate the relationship between LANA, p53, and hdm2, we purified LANA complexes from PEL by column chromatography. This confirmed that LANA bound p53. However, the LANA:p53 complexes were a minority compared to hdm2:p53 and p53:p53 complexes. The half-life of p53 was not extended, which is in contrast to the half-life of simian virus 40 T antigen-transformed cells. p53:p53, LANA:p53, and LANA:LANA complexes coexisted in PEL, and each protein was able to bind to its cognate DNA element. These data suggest that under normal conditions, p53 is inactive in PEL, thus allowing for exponential growth, but that this inactivation is driven by the relative stoichiometries of LANA, hdm2, and p53. If p53 is activated by DNA damage or nutlin-3a, the complex falls apart easily, and p53 exercises its role as guardian of the genome.

BackgroundGenome-wide association studies (GWAS) have linked common single nucleotide polymorphisms (SNPs) on chromosome 9p21 near the INK4/ARF (CDKN2A/B) tumor suppressor locus with risk of atherosclerotic diseases and type 2 diabetes mellitus. To explore the mechanism of this association, we investigated whether expression of proximate transcripts (p16(INK4a), p15(INK4b), ARF, ANRIL and MTAP) correlate with genotype of representative 9p21 SNPs.Methodology/principal findingsWe analyzed expression of 9p21 transcripts in purified peripheral blood T-cells (PBTL) from 170 healthy donors. Samples were genotyped for six selected disease-related SNPs spanning the INK4/ARF locus. Correlations among these variables were determined by univariate and multivariate analysis. Significantly reduced expression of all INK4/ARF transcripts (p15(INK4b), p16(INK4a), ARF and ANRIL) was found in PBTL of individuals harboring a common SNP (rs10757278) associated with increased risk of coronary artery disease, stroke and aortic aneurysm. Expression of MTAP was not influenced by rs10757278 genotype. No association of any these transcripts was noted with five other tested 9p21 SNPs.Conclusions/significanceGenotypes of rs10757278 linked to increased risk of atherosclerotic diseases are also associated with decreased expression in PBTL of the INK4/ARF locus, which encodes three related anti-proliferative transcripts of known importance in tumor suppression and aging.

Multiple myeloma (MM) is an incurable hematologic malignancy primarily of older adults. MM treatment decisions are based partially upon chronologic age, a measure that may not reflect the patients’ physiologic age or ability to tolerate therapy. Recently, investigators have established methodology to better quantify biologic age using the molecular marker, p16INK4a (p16). p16 expression is a marker of cellular senescence and is strongly associated with gerontogenic models. p16 rises exponentially with chronologic aging and is influenced by external factors such as physical activity, tobacco use, and solid tumor chemotherapy. Additionally, single nucleotide polymorphisms located near the p16-encoding INK4/ARF locus are linked to age-related diseases (e.g. cardiovascular disease, diabetes, glaucoma) and decreased physical function. p16 mRNA can be measured in peripheral blood T-cells thus providing a practical means of quantifying this molecular marker of age. To determine the effects of MM therapy and autologous hematopoietic stem cell transplant (AHSCT) on biologic aging, we serially measured T-cell p16 expression in MM cohorts and aged matched controls. Methods: 23 MM patients were divided into cohorts of newly diagnosed (ND; n=11) and prior treatment (T; n=12). T-cell isolation was performed using techniques described by Liu and colleagues (Liu et al. Aging Cell 2009); p16 expression was measured using quantitative RT-PCR. 16 MM patients underwent sequential testing, with a median 42 days between each measurement. During this time, 8 patients had no intervention and 8 received immune modulatory (IMiD) therapy. Healthy age matched control T-cells were analyzed for comparison (n=17). Results: MM patients with a median age of 62 were evaluated; 12 with early stage ISS disease, 21 with an ECOG performance status of 0-1, and 6 with high risk FISH abnormalities. 12 MM patients had prior treatment, most included AHSCT (n=11). MM treated patients had several lines of therapy; half with 1-2 lines and half with 3+ lines. Median time from AHSCT to p16 analysis was 1003 days (range 49-3630) and transplant date was unrelated to p16 expression (p=0.9577). The healthy control median age was 60 (SD 11.77) with a range of 35-82 years. T-cell yield among MM patients and healthy controls was not significantly different. Using univariate linear regression, age correlates significantly with p16 expression in healthy controls (p=0.0039) wherein p16 is estimated to increase by 1.035 fold each year [0.05 Cts per year]. Using multivariable regression analysis, age and MM status (ND and T), were both independently associated with p16 expression. When controlling for age, patients previously treated for MM had p16 expression that was ~3.68-fold higher than healthy controls (p=0.0003). There was no significant difference in p16 expression between ND MM patients and healthy controls (fold-change=1.15, p=0.70). MM p16 levels were significantly higher in patients with prior therapy (p=0.0439) and for those who had underwent AHSCT (p=0.0129). However, p16 was unrelated to other clinical factors such as cardiovascular disease, tobacco use, radiation, stage, absolute lymphocyte count, or renal function. 8 MM patients where p16 expression was measured pre and post-IMiD treatment, a significant change in expression was not observed (median percent change: 1.16%, p=0.11); in another 8 MM patients who were untreated, p16 levels were also unchanged over time (median percent change: -0.91%, p=0.38). Conclusions: AHSCT significantly impacts p16 expression in T-cells from MM patients. Specifically, MM patients post-AHSCT show a 3.68 fold increase in p16 expression compared to age-matched controls. Time from transplant to assessment does not impact p16 measurements, suggesting that cellular senescence of the T-cell compartment following AHSCT is persistent. MM patients exhibit known T-cell defects including variable T-cell frequency, abnormal signal transduction, and impaired cytokine secretion. Moreover, MM AHSCT patients also show impaired immune reconstitution with changes in T-cell frequency and function. To our knowledge, this is the first report describing cellular senescence post-transplant. Health status and function are affected by AHSCT; our work is important in understanding how biologic markers of age change with intensive therapy, such as AHSCT, to better predict outcomes in future studies. Disclosures Hofmeister: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millenium: Honoraria, Research Funding; ARNO Therapeutics: Research Funding; Onyx: Membership on an entity's Board of Directors or advisory committees.

Prostatic adenocarcinoma is the most frequently diagnosed malignancy in the United States and is the second leading cause of cancer deaths among men (Landis et al., 1998). Most prostate cancers are treated by androgen ablation, since androgen is a required mitogen for the survival and proliferation of prostate cells (Cunha et al., 1987; Jenster, 1999; Klotz, 2000; Labrie, 2000). This treatment is initially effective, as upon androgen withdrawal most prostate cancer cells undergo cell cycle arrest or cell death (Denmeade et al., 1996; Murphy et al., 1991; Westin et al., 1995). Unfortunately, androgen independent tumors arise and lead to patient morbidity. Determination of how androgen exerts its effect as a mitogen in early prostate cancer, and how the androgen requirement is subverted in advanced disease is the focus of intensive research.