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Background: Lynch syndrome is a hereditary cancer predisposition syndrome caused by germline mutations in DNA mismatch repair genes, which lead to high microsatellite instability and frameshift mutations at coding mononucleotide repeats in the genome. Recurrent frameshift mutations in these regions are thought to play a central role in the increased risk of various cancers, but no biomarkers are currently available for the surveillance of high microsatellite instability-associated cancers., Methods: A frameshift mutation-based biomarker panel was developed and validated by targeted next-generation sequencing of supernatant DNA from cultured high microsatellite instability colorectal cancer cells. This panel supported selection of 122 frameshift mutation targets as potential biomarkers. This biomarker panel was then tested using matched tumor, adjacent normal tissue, and buffy coat samples (53 samples) and blood-derived cell-free DNA (cfDNA) (38 samples) obtained from 45 high microsatellite instability and mismatch repair-deficient patients. We also sequenced cfDNA from 84 healthy participants to assess background noise., Results: Recurrent frameshift mutations at coding mononucleotide repeats were detectable not only in tumors but also in cfDNA from high microsatellite instability and mismatch repair-deficient patients, including a Lynch syndrome carrier, with a varying range of target detection (up to 85.2%), whereas they were virtually undetectable in healthy participants. Receiver operating characteristic curve analysis showed high sensitivity and specificity (area under the curve = 0.94) of the investigated panel., Conclusions: We demonstrated that frameshift mutations can be detected in cfDNA from high microsatellite instability and mismatch repair-deficient patients and asymptomatic carriers. The 122-target frameshift mutation panel described here has promise as a tool for improved surveillance of high microsatellite instability and mismatch repair-deficient patients, with the potential to reduce the frequency of invasive screening methods for this high-cancer-risk cohort., (Published by Oxford University Press 2024.)

Recent preclinical studies have shown that the intake of nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin and naproxen could be an effective intervention strategy against TMPRSS2-ERG fusion-driven prostate tumorigenesis. Herein, as a follow-up mechanistic study, employing TMPRSS2-ERG (fusion) positive tumors and plasma from TMPRSS2-ERG. Pten flox/flox mice, we profiled the stage specific proteomic changes (focused on inflammatory circulating and prostate tissue/tumor-specific cytokines, chemokines, and growth factors/growth signaling-associated molecules) that contribute to prostate cancer (PCa) growth and progression in the TMPRSS2-ERG fusion-driven mouse model of tumorigenesis. In addition, the association of the protective effects of NSAIDs (aspirin 1400 ppm and naproxen 400 ppm) with the modulation of these specific molecular pathways was determined. A sandwich Elisa based membrane array-proteome profiler identifying 111 distinct signaling molecules was employed. Overall, the plasma and prostate tissue sample analyses identified 54 significant and differentially expressed cytokines, chemokines, and growth factors/growth signaling-associated molecules between PCa afflicted mice (TMPRSS2-ERG. Pten flox/flox , age-matched noncancerous controls, NSAIDs-supplemented and no-drug controls). Bioinformatic analysis of the array outcomes indicated that the protective effect of NSAIDs was associated with reduced expression of (a) tumor promoting inflammatory molecules (M-CSF, IL-33, CCL22, CCL12, CX3CL1, CHI3L1, and CD93), (b) growth factors- growth signaling-associated molecules (Chemerin, FGF acidic, Flt-3 ligand, IGFBP-5, and PEDF), and (c) tumor microenvironment/stromal remodeling proteins MMP2 and MMP9. Overall, our findings corroborate the pathological findings that protective effects of NSAIDs in TMPSS2-ERG fusion-driven prostate tumorigenesis are associated with antiproliferative and anti-inflammatory effects and possible modulation of the immune cell enriched microenvironment., (© 2024 Wiley Periodicals LLC.)

Cancer prevention and early detection, the first two of the eight primary goals of the National Cancer Plan released in April 2023, are at the forefront of the nation's strategic efforts to reduce cancer incidence and mortality. The Division of Cancer Prevention (DCP) of the NCI is the federal government's principal component devoted to promoting and supporting innovative cancer prevention research. Recent advances in tumor immunology, cancer immunotherapy, and vaccinology strongly suggest that the host immune system can be effectively harnessed to elicit protective immunity against the development of cancer, that is, cancer immunoprevention. Cancer immunoprevention may be most effective if the intervention is given before or early in the carcinogenic process while the immune system remains relatively uncompromised. DCP has increased the emphasis on immunoprevention research in recent years and continues to expand program resources and interagency collaborations designed to facilitate research in the immunoprevention field. These resources support a wide array of basic, translational, and clinical research activities, including discovery, development, and validation of biomarkers for cancer risk assessment and early detection (Early Detection Research Network), elucidation of biological and pathophysiological mechanistic determinants of precancer growth and its control (Translational and Basic Science Research in Early Lesions), spatiotemporal multiomics characterization of precancerous lesions (Human Tumor Atlas Network/Pre-Cancer Atlas), discovery of immunoprevention pathways and immune targets (Cancer Immunoprevention Network), and preclinical and clinical development of novel agents for immunoprevention and interception (Cancer Prevention-Interception Targeted Agent Discovery Program, PREVENT Cancer Preclinical Drug Development Program, and Cancer Prevention Clinical Trials Network)., (©2024 American Association for Cancer Research.)

The concept of green chemoprevention was introduced in 2012 by Drs. Jed Fahey and Thomas Kensler as whole-plant foods and/or extract-based interventions demonstrating cancer prevention activity. Refining concepts and research demonstrating proof-of-principle approaches are highlighted within this review. Early approaches included extensively investigated whole foods, including broccoli sprouts and black raspberries showing dose-responsive effects across a range of activities in both animals and humans with minimal or no apparent toxicity. A recent randomized crossover trial evaluating the detoxification of tobacco carcinogens by a broccoli seed and sprout extract in the high-risk cohort of current smokers highlights the use of a dietary supplement as a potential next-generation green chemoprevention or green cancer prevention approach. Challenges are addressed, including the selection of dose, duration and mode of delivery, choice of control group, and standardization of the plant food or extract. Identification and characterization of molecular targets and careful selection of high-risk cohorts for study are additional important considerations when designing studies. Goals for precision green cancer prevention include acquiring robust evidence from carefully controlled human studies linking plant foods, extracts, and compounds to modulation of targets for cancer risk reduction in individual cancer types., (©2024 The Authors; Published by the American Association for Cancer Research.)

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that has a poor prognosis. TOP2A is a key enzyme in DNA replication and is a therapeutic target for breast and other cancers. TOP2A-specific Th1-promoting epitopes with optimal binding affinity to MHC II were identified using a combined scoring system. The multi-peptide TOP2A vaccine elicited a robust immunologic response in immunized mice, as demonstrated by the significant production of Th1 cytokines from immunized animals' splenocytes stimulated in vitro with TOP2A peptides. Anti-tumor efficacy of the TOP2A vaccine was demonstrated in a syngeneic TNBC mouse model, in which pre-graft preventive vaccination was associated with significantly decreased tumor growth as compared to adjuvant control. In a genetically engineered mouse (GEM) model of TNBC, vaccinated animals demonstrated a significant reduction in tumor incidence and average tumor volume compared to adjuvant control. Finally, we examined TCR sequences in CD4 tumor Infiltrating lymphocytes (TIL) from vaccinated mice and found that the TIL contained TCR sequences specific to the three vaccine peptides. These data indicate that our newly developed multi-peptide TOP2A vaccine is highly immunogenic, elicits TILs with vaccine specific TCRs, and is highly effective in preventing and intercepting TNBC development and progression in vivo., (© 2023. Nature Publishing Group UK.)

The consumption of the non-steroidal anti-inflammatory drug (NSAID) aspirin is associated with a significant reduction in the risk of developing TMPRSS2-ERG (fusion)-positive prostate cancer (PCa) compared to fusion-negative PCa in population-based case-control studies; however, no extensive preclinical studies have been conducted to investigate and confirm these protective benefits. Thus, the focus of this study was to determine the potential usefulness of aspirin and another NSAID, naproxen, in PCa prevention, employing preclinical models of both TMPRSS2-ERG (fusion)-driven (with conditional deletion of Pten ) and non- TMPRSS2-ERG -driven (Hi-Myc +/- mice) PCa. Male mice ( n = 25 mice/group) were fed aspirin- (700 and 1400 ppm) and naproxen- (200 and 400 ppm) supplemented diets from (a) 6 weeks until 32 weeks of Hi-Myc +/- mice age; and (b) 1 week until 20 weeks post-Cre induction in the fusion model. In all NSAID-fed groups, compared to no-drug controls, there was a significant decrease in higher-grade adenocarcinoma incidence in the TMPRSS2-ERG (fusion)-driven PCa model. Notably, there were no moderately differentiated (MD) adenocarcinomas in the dorsolateral prostate of naproxen groups, and its incidence also decreased by ~79-91% in the aspirin cohorts. In contrast, NSAIDs showed little protective effect against prostate tumorigenesis in Hi-Myc +/- mice, suggesting that NSAIDs exert a specific protective effect against TMPRSS2-ERG (fusion)-driven PCa.

Background: Genome integrity is essential for the survival of an organism. DNA mismatch repair (MMR) genes (e.g., MLH1, MSH2, MSH6 , and PMS2 ) play a critical role in the DNA damage response pathway for genome integrity maintenance. Germline mutations of MMR genes can lead to Lynch syndrome or constitutional mismatch repair deficiency syndrome, resulting in an increased lifetime risk of developing cancer characterized by high microsatellite instability (MSI-H) and high mutation burden. Although immunotherapy has been approved for MMR-deficient (MMRd) cancer patients, the overall response rate needs to be improved and other management options are needed., Methods: To better understand the biology of MMRd cancers, elucidate the resistance mechanisms to immune modulation, and develop vaccines and therapeutic testing platforms for this high-risk population, we generated organoids and an orthotopic mouse model from intestine tumors developed in a Msh2-deficient mouse model, and followed with a detailed characterization., Results: The organoids were shown to be of epithelial origin with stem cell features, to have a high frameshift mutation frequency with MSI-H and chromosome instability, and intra- and inter-tumor heterogeneity. An orthotopic model using intra-cecal implantation of tumor fragments derived from organoids showed progressive tumor growth, resulting in the development of adenocarcinomas mixed with mucinous features and distant metastasis in liver and lymph node., Conclusions: The established organoids with characteristics of MSI-H cancers can be used to study MMRd cancer biology. The orthotopic model, with its distant metastasis and expressing frameshift peptides, is suitable for evaluating the efficacy of neoantigen-based vaccines or anticancer drugs in combination with other therapies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer WL declared a shared affiliation with the authors SB, SS, and RS to the handling editor at the time of review., (Copyright © 2023 Song, Kerr, Sanders, Dai, Baxter, Somerville, Baugher, Mellott, Young, Lawhorn, Plona, Xu, Wei, Hu, Liu, Hutson, Karim, Burkett, Difilippantonio, Pinto, Gebert, Kloor, Lipkin, Sei and Shoemaker.)

The species and tissue specificities of HPV (human papillomavirus) for human infection and disease complicates the process of prophylactic vaccine development in animal models. HPV pseudoviruses (PsV) that carry only a reporter plasmid have been utilized in vivo to demonstrate cell internalization in mouse mucosal epithelium. The current study sought to expand the application of this HPV PsV challenge model with both oral and vaginal inoculation and to demonstrate its utility for testing vaccine-mediated dual-site immune protection against several HPV PsV types. We observed that passive transfer of sera from mice vaccinated with the novel experimental HPV prophylactic vaccine RG1-VLPs (virus-like particles) conferred HPV16-neutralizing as well as cross-neutralizing Abs against HPV39 in naïve recipient mice. Moreover, active vaccination with RG1-VLPs also conferred protection to challenge with either HPV16 or HPV39 PsVs at both vaginal and oral sites of mucosal inoculation. These data support the use of the HPV PsV challenge model as suitable for testing against diverse HPV types at two sites of challenge (vaginal vault and oral cavity) associated with the origin of the most common HPV-associated cancers, cervical cancer and oropharyngeal cancer., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jason Marshall reports financial support was provided by National Cancer Institute. Richard Roden, Reinhard Kirnbauer reports a relationship with Pathovax LLC that includes: board membership and equity or stocks. Richard Roden, Reinhard Kirnbauer has patent Papillomavirus-like particles (VLP) as broad spectrum human papillomavirus (HPV) vaccines issued to Pathovax LLC., (Copyright © 2023. Published by Elsevier Ltd.)

The continuing emergence of SARS-CoV-2 variants has highlighted the need to identify additional points for viral inhibition. Ribosome inactivating proteins (RIPs), such as MAP30 and Momordin which are derived from bitter melon (Momordica charantia), have been found to inhibit a broad range of viruses. MAP30 has been shown to potently inhibit HIV-1 with minimal cytotoxicity. Here we show that MAP30 and Momordin potently inhibit SARS-CoV-2 replication in A549 human lung cells (IC50 ~ 0.2 μM) with little concomitant cytotoxicity (CC50 ~ 2 μM). Both viral inhibition and cytotoxicity remain unaltered by appending a C-terminal Tat cell-penetration peptide to either protein. Mutation of tyrosine 70, a key residue in the active site of MAP30, to alanine completely abrogates both viral inhibition and cytotoxicity, indicating the involvement of its RNA N-glycosylase activity. Mutation of lysine 171 and lysine 215, residues corresponding to those in Ricin which when mutated prevented ribosome binding and inactivation, to alanine in MAP30 decreased cytotoxicity (CC50 ~ 10 μM) but also the viral inhibition (IC50 ~ 1 μM). Unlike with HIV-1, neither Dexamethasone nor Indomethacin exhibited synergy with MAP30 in the inhibition of SARS-CoV-2. From a structural comparison of the two proteins, one can explain their similar activities despite differences in both their active-sites and ribosome-binding regions. We also note points on the viral genome for potential inhibition by these proteins., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Advances in molecular diagnostics have led to improved diagnosis and molecular understanding of hereditary cancers in the clinic. Improving the management, treatment, and potential prevention of cancers in carriers of predisposing mutations requires preclinical experimental models that reflect the key pathogenic features of the specific syndrome associated with the mutations. Numerous genetically engineered mouse (GEM) models of hereditary cancer have been developed. In this review, we describe the models of Lynch syndrome and hereditary breast and ovarian cancer syndrome, the two most common hereditary cancer predisposition syndromes. We focus on Lynch syndrome models as illustrative of the potential for using mouse models to devise improved approaches to prevention of cancer in a high-risk population. GEM models are an invaluable tool for hereditary cancer models. Here, we review GEM models for some hereditary cancers and their potential use in cancer prevention studies., (Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Epidermal growth factor receptor (EGFR) mutations occur in about 50% of lung adenocarcinomas in Asia and about 15% in the US. EGFR mutation-specific inhibitors have been developed and made significant contributions to controlling EGFR mutated non-small cell lung cancer. However, resistance frequently develops within 1 to 2 years due to acquired mutations. No effective approaches that target mutant EGFR have been developed to treat relapse following tyrosine kinase inhibitor (TKI) treatment. Vaccination against mutant EGFR is one area of active exploration. In this study, we identified immunogenic epitopes for the common EGFR mutations in humans and formulated a multi-peptide vaccine (E mut Vax) targeting the EGFR L858R, T790M, and Del19 mutations. The efficacy of the E mut Vax was evaluated in both syngeneic and genetic engineered EGFR mutation-driven murine lung tumor models with prophylactic settings, where the vaccinations were given before the onset of the tumor induction. The multi-peptide E mut Vax effectively prevented the onset of EGFR mutation-driven lung tumorigenesis in both syngeneic and genetically engineered mouse models (GEMMs). Flow cytometry and single-cell RNA sequencing were conducted to investigate the impact of E mut Vax on immune modulation. E mut Vax significantly enhanced Th1 responses in the tumor microenvironment and decreased suppressive Tregs to enhance anti-tumor efficacy. Our results show that multi-peptide E mut Vax is effective in preventing common EGFR mutation-driven lung tumorigenesis, and the vaccine elicits broad immune responses that are not limited to anti-tumor Th1 response., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pan, Xiong, Zhang, Palen, Shoemaker, Johnson, Sei, Wang and You.)

Colorectal cancer (CRC) is the third most prevalent and second deadliest cancer worldwide. In addition, metastasis directly causes up to 90% of all CRC deaths, highlighting the metastatic burden of the disease. Biomarkers such as S100A4 and MACC1 aid in identifying patients with a high risk of metastasis formation. High expression of S100A4 or MACC1 and to a greater extent the combination of both biomarkers is a predictor for metastasis and poor patient survival in CRC. MACC1 is a tumor-initiating and metastasis-promoting oncogene, whereas S100A4 has not been shown to initiate tumor formation but can, nevertheless, promote malignant tumor growth and metastasis formation. Cantharidin is a natural drug extracted from various blister beetle species, and its demethylated analogue norcantharidin has been shown in several studies to have an anti-cancer and anti-metastatic effect in different cancer entities such as CRC, breast cancer, and lung cancer. The impact of the natural compound cantharidin and norcantharidin on S100A4 and MACC1 gene expression, cancer cell migration, motility, and colony formation in vitro was tested. Here, for the first time, we have demonstrated that cantharidin and norcantharidin are transcriptional inhibitors of S100A4 and MACC1 mRNA expression, protein expression, and motility in CRC cells. Our results clearly indicate that cantharidin and, to a lesser extent, its analogue norcantharidin are promising compounds for efficient anti-metastatic therapy targeting the metastasis-inducing genes S100A4 and MACC1 for personalized medicine for cancer patients.

Lung cancer is the leading cause of cancer death worldwide. Vaccination against EGFR can be one of the venues to prevent lung cancer. Blocking glutamine metabolism has been shown to improve anticancer immunity. Here, the authors report that JHU083, an orally active glutamine antagonist prodrug designed to be preferentially activated in the tumor microenvironment, has potent anticancer effects on EGFR-driven mouse lung tumorigenesis. Lung tumor development is significantly suppressed when treatment with JHU083 is combined with an EGFR peptide vaccine (EVax) than either single treatment. Flow cytometry and single-cell RNA sequencing of the lung tumors reveal that JHU083 increases CD8 + T cell and CD4 + Th1 cell infiltration, while EVax elicits robust Th1 cell-mediated immune responses and protects mice against EGFR L858R mutation-driven lung tumorigenesis. JHU083 treatment decreases immune suppressive cells, including both monocytic- and granulocytic-myeloid-derived suppressor cells, regulatory T cells, and pro-tumor CD4 + Th17 cells in mouse models. Interestingly, Th1 cells are found to robustly upregulate oxidative metabolism and adopt a highly activated and memory-like phenotype upon glutamine inhibition. These results suggest that JHU083 is highly effective against EGFR-driven lung tumorigenesis and promotes an adaptive T cell-mediated tumor-specific immune response that enhances the efficacy of EVax., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The recent emergence of multiple SARS-CoV-2 variants has caused considerable concern due to both reduced vaccine efficacy and escape from neutralizing antibody therapeutics. It is, therefore, paramount to develop therapeutic strategies that inhibit all known and future SARS-CoV-2 variants. Here, we report that all SARS-CoV-2 variants analyzed, including variants of concern (VOC) Alpha, Beta, Gamma, Delta, and Omicron, exhibit enhanced binding affinity to clinical grade and phase 2 tested recombinant human soluble ACE2 (APN01). Importantly, soluble ACE2 neutralized infection of VeroE6 cells and human lung epithelial cells by all current VOC strains with markedly enhanced potency when compared to reference SARS-CoV-2 isolates. Effective inhibition of infections with SARS-CoV-2 variants was validated and confirmed in two independent laboratories. These data show that SARS-CoV-2 variants that have emerged around the world, including current VOC and several variants of interest, can be inhibited by soluble ACE2, providing proof of principle of a pan-SARS-CoV-2 therapeutic., (©2022 The Authors. Published under the terms of the CC BY 4.0 license.)

As ACE2 is the critical SARS-CoV-2 receptor, we hypothesized that aerosol administration of clinical grade soluble human recombinant ACE2 (APN01) will neutralize SARS-CoV-2 in the airways, limit spread of infection in the lung, and mitigate lung damage caused by deregulated signaling in the renin-angiotensin (RAS) and Kinin pathways. Here, after demonstrating in vitro neutralization of SARS-CoV-2 by APN01, and after obtaining preliminary evidence of its tolerability and preventive efficacy in a mouse model, we pursued development of an aerosol formulation. As a prerequisite to a clinical trial, we evaluated both virus binding activity and enzymatic activity for cleavage of Ang II following aerosolization. We report successful aerosolization for APN01, retaining viral binding as well as catalytic RAS activity. Dose range-finding and IND-enabling repeat-dose aerosol toxicology testing were conducted in dogs. Twice daily aerosol administration for two weeks at the maximum feasible concentration revealed no notable toxicities. Based on these results, a Phase I clinical trial in healthy volunteers has now been initiated (NCT05065645), with subsequent Phase II testing planned for individuals with SARS-CoV-2 infection., Competing Interests: Gerald Wirnsberger and Sonja Holler and Romana Gugensberger were employed by Apeiron Biologics A.G. Apeiron supplied the APN01 for study. Josef M. Pettinger was a founder of Apeiron, is a current shareholder and inventor of APN01. David L. McCormick is a Section Editor for PLOS One. Other authors declare no competing interests.

In the present study, we performed a comparative stage-specific pathological and molecular marker evaluation of TMPRSS2-ERG fusion and PTEN loss-driven (TMPRSS2-ERG. Pten flox/flox ) versus non-fusion-driven prostate tumorigenesis (Hi-Myc) in mice. Anterior, ventral, and dorsolateral prostates were collected from mice at different ages (or time points post-Cre induction). Results indicated that growth and progression of prostatic intraepithelial lesions to adenocarcinoma stages occurred in both mice models albeit at different rates. In the TMPRSS2-ERG. Pten flox/flox mice, the initiation of tumorigenesis was slow, but subsequent progression through different stages became increasingly faster. Adenocarcinoma stage was reached early on; however, no high-grade undifferentiated tumors were observed. Conversely, in the Hi-Myc +/ - mice, tumorigenesis initiation was rapid; however, progression through different stages was relatively slower and it took a while to reach the more aggressive phenotype stage. Nevertheless, at the advanced stages in the Hi-Myc +/ - mice, high-grade undifferentiated tumors were observed compared to the later stage tumors observed in the fusion-driven TMPRSS2-ERG. Pten flox/flox mice. These results were corroborated by the stage specific-pattern in the molecular expression of proliferation markers (PCNA and c-Myc); androgen receptor (AR); fusion-resultant overexpression of ERG; Prostein (SLC45-A3); and angiogenesis marker (CD-31). Importantly, there was a significant increase in immune cell infiltrations, which increased with the stage of tumorigenesis, in the TMPRSS2-ERG fusion-positive tumors relative to fusion negative tumors. Together, these findings are both novel and highly significant in establishing a working preclinical model for evaluating the efficacy of interventions during different stages of tumorigenesis in TMPRSS2-ERG fusion-driven PCa., (© 2022 Wiley Periodicals LLC.)

Malignant mesothelioma (MMe) is a rare malignancy originating from the linings of the pleural, peritoneal and pericardial cavities. The best-defined risk factor is exposure to carcinogenic mineral fibers (e.g., asbestos). Genomic studies have revealed that the most frequent genetic lesions in human MMe are mutations in tumor suppressor genes. Several genetically engineered mouse models have been generated by introducing the same genetic lesions found in human MMe. However, most of these models require specialized breeding facilities and long-term exposure of mice to asbestos for MMe development. Thus, an alternative model with high tumor penetrance without asbestos is urgently needed. We characterized an orthotopic model using MMe cells derived from Cdkn2a +/- ;Nf2 +/- mice chronically injected with asbestos. These MMe cells were tumorigenic upon intraperitoneal injection. Moreover, MMe cells showed mixed chromosome and microsatellite instability, supporting the notion that genomic instability is relevant in MMe pathogenesis. In addition, microsatellite markers were detectable in the plasma of tumor-bearing mice, indicating a potential use for early cancer detection and monitoring the effects of interventions. This orthotopic model with rapid development of MMe without asbestos exposure represents genomic instability and specific molecular targets for therapeutic or preventive interventions to enable preclinical proof of concept for the intervention in an immunocompetent setting.

Early-onset colorectal cancer (EOCRC), defined as a diagnosis under age 50, is an emerging public health burden. As many of these individuals fall outside of screening guidelines, the development of a minimally invasive, accurate screening modality for this population is warranted. We evaluated the FDA-approved blood-based biomarker methylated Septin9 (m SEPT9 ) test as screening tool for EOCRC. EOCRC plasma, healthy plasma, and serum-free conditioned media from cancer cell lines was collected. Cell-free DNA (cfDNA) was isolated and bisulfite converted for use in the assay. m SEPT9 and ACTB measured using Epi proColon ® V2.0. EOCRC plasma was collected at Massachusetts General Hospital (2005-2019) and controls were collected at the National Institutes of Health and by ZenBio Inc. (prior to 2019). Twenty-seven EOCRC cases, 48 healthy controls <50 years old, and 39 healthy controls ≥50 years old were included in this study. m SEPT9 was detected more frequently in EOCRC cases (88.9%) compared to healthy controls age <50 (4.2%) and ≥50 (15.4%), respectively ( p <0.001). The sensitivity, specificity, positive predictive value, and negative predictive values of the m SEPT9 assay to detect EOCRC was 90.8% (95% CI: 84.7-96.9%), 88.9% (95% CI: 77.0-100.0%), 96.3% (95% CI: 92.3-100.0%), and 75.0% (95% CI 60.0-90.0%), respectively, compared to all healthy controls. m SEPT9 cfDNA level was an independent predictor of survival ( p =0.02). m SEPT9 is a sensitive and specific biomarker for EOCRC detection. These results suggest that m SEPT9 may be useful in the detection of EOCRC, providing a minimally invasive method for screening in this growing population of CRC patients., Competing Interests: All other authors declare that they have no conflicts of interest. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

The National Cancer Institute (NCI) Division of Cancer Prevention (DCP) convened the "Translational Advances in Cancer Prevention Agent Development (TACPAD) Workshop on Immunomodulatory Agents" as a virtual 2-day workshop on September 13 to 14, 2021. The main goals of this workshop were to foster the exchange of ideas and potentially new collaborative interactions among leading cancer immunoprevention researchers from basic and clinical research and highlight new and emerging trends in immunoprevention. The workshop included an overview of the mechanistic classes of immunomodulatory agents and three sessions covering the gamut from preclinical to clinical studies. The workshop convened individuals working in immunology and cancer prevention to discuss trends in discovery and development of immunomodulatory agents individually and in combination with other chemopreventive agents or vaccines., Competing Interests: CONFLICTS OF INTEREST Opinions expressed by the authors are their own and this material should not be interpreted as representing the official viewpoint of the U.S. Department of Health and Human Services, the National Institutes of Health, or the National Cancer Institute. Drs. Dashwood, Dickinson, Disis, Jaffee, Khleif, Miller, Mohammed, Pollak, Schlom, Shoemaker, Wondrak, You and Zhu have no FCOIs to declare. Dr. Johnson received support from Miltenyi Biotec. Dr. Stanton received research support through her institute from IMV Therapeutics., (Copyright © 2021 Korean Society of Cancer Prevention.)

Metastasis is directly linked to colorectal cancer (CRC) patient survival. Wnt signaling through β-catenin plays a key role. Metastasis-inducing S100A4 is a Wnt/β-catenin target gene and a prognostic biomarker for CRC and other cancer types. We aimed to identify S100A4-dependent expression alterations to better understand CRC progression and metastasis for improved patient survival. S100A4-induced transcriptome arrays, confirmatory studies in isogenic CRC cell lines with defined β-catenin genotypes, and functional metastasis studies were performed. S100A4-regulated transcriptome examination revealed the transcriptional cross-regulation of metastasis-inducing S100A4 with Wnt pathway antagonist Dickkopf-1 (DKK1). S100A4 overexpression down-regulated DKK1, S100A4 knock-down increased DKK1. Recombinant DKK1 reduced S100A4 expression and S100A4-mediated cell migration. In xenografted mice, systemic S100A4-shRNA application increased intratumoral DKK1. The inverse correlation of S100A4 and DKK1 was confirmed in five independent publicly available CRC expression datasets. Combinatorial analysis of S100A4 and DKK1 in two additional independent CRC patient cohorts improved prognosis of overall and metastasis-free survival. The newly discovered transcriptional cross-regulation of Wnt target S100A4 and Wnt antagonist DKK1 is predominated by an S100A4-induced Wnt signaling feedback loop, increasing cell motility and metastasis risk. S100A4 and DKK1 combination improves the identification of CRC patients at high risk.

The tumor suppressor BRCA2 protects stalled forks from degradation to maintain genome stability. However, the molecular mechanism(s) whereby unprotected forks are stabilized remains to be fully characterized. Here, we demonstrate that WRN helicase ensures efficient restart and limits excessive degradation of stalled forks in BRCA2-deficient cancer cells. In vitro, WRN ATPase/helicase catalyzes fork restoration and curtails MRE11 nuclease activity on regressed forks. We show that WRN helicase inhibitor traps WRN on chromatin leading to rapid fork stalling and nucleolytic degradation of unprotected forks by MRE11, resulting in MUS81-dependent double-strand breaks, elevated non-homologous end-joining and chromosomal instability. WRN helicase inhibition reduces viability of BRCA2-deficient cells and potentiates cytotoxicity of a poly (ADP)ribose polymerase (PARP) inhibitor. Furthermore, BRCA2-deficient xenograft tumors in mice exhibited increased DNA damage and growth inhibition when treated with WRN helicase inhibitor. This work provides mechanistic insight into stalled fork stabilization by WRN helicase when BRCA2 is deficient., (© 2021. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background & Aims: DNA mismatch repair deficiency drives microsatellite instability (MSI). Cells with MSI accumulate numerous frameshift mutations. Frameshift mutations affecting cancer-related genes may promote tumorigenesis and, therefore, are shared among independently arising MSI tumors. Consequently, such recurrent frameshift mutations can give rise to shared immunogenic frameshift peptides (FSPs) that represent ideal candidates for a vaccine against MSI cancer. Pathogenic germline variants of mismatch repair genes cause Lynch syndrome (LS), a hereditary cancer syndrome affecting approximately 20-25 million individuals worldwide. Individuals with LS are at high risk of developing MSI cancer. Previously, we demonstrated safety and immunogenicity of an FSP-based vaccine in a phase I/IIa clinical trial in patients with a history of MSI colorectal cancer. However, the cancer-preventive effect of FSP vaccination in the scenario of LS has not yet been demonstrated., Methods: A genome-wide database of 488,235 mouse coding mononucleotide repeats was established, from which a set of candidates was selected based on repeat length, gene expression, and mutation frequency. In silico prediction, in vivo immunogenicity testing, and epitope mapping was used to identify candidates for FSP vaccination., Results: We identified 4 shared FSP neoantigens (Nacad [FSP-1], Maz [FSP-1], Senp6 [FSP-1], Xirp1 [FSP-1]) that induced CD4/CD8 T cell responses in naïve C57BL/6 mice. Using VCMsh2 mice, which have a conditional knockout of Msh2 in the intestinal tract and develop intestinal cancer, we showed vaccination with a combination of only 4 FSPs significantly increased FSP-specific adaptive immunity, reduced intestinal tumor burden, and prolonged overall survival. Combination of FSP vaccination with daily naproxen treatment potentiated immune response, delayed tumor growth, and prolonged survival even more effectively than FSP vaccination alone., Conclusions: Our preclinical findings support a clinical strategy of recurrent FSP neoantigen vaccination for LS cancer immunoprevention., (Published by Elsevier Inc.)

MicroRNAs are potential candidates for lung cancer prevention and therapy. A major limitation is the lack of an efficient delivery system to directly deliver miRNA to cancer cells while limiting systemic exposure. The delivery of miRNA via inhalation is a potential strategy for lung cancer prevention in high-risk individuals. In this study, the authors investigate the efficacy of aerosolized let-7b miRNA treatment in lung cancer prevention. Let-7b shows significant inhibition of B[a]P-induced lung adenoma with no detectable side effects. Single-cell RNA sequencing of tumor-infiltrating T cells from primary tumors reveals that Let-7b post-transcriptionally suppresses PD-L1 and PD-1 expression in the tumor microenvironment, suggesting that let-7b miRNAs may promote antitumor immunity in vivo. Let-7b treatment decreases the expression of PD-1 in CD8+ T cells and reduces PD-L1 expression in lung tumor cells. The results suggest that this aerosolized let-7b mimic is a promising approach for lung cancer prevention, and that the in vivo tumor inhibitory effects of let-7b are mediated, at least in part, by immune-promoting effects via downregulating PD-L1 in tumors and/or PD-1 on CD8+ T cells. These changes potentiate antitumor CD8+ T cell immune responses, and ultimately lead to tumor inhibition., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Current human papillomavirus (HPV) vaccines provide substantial protection against the most common HPV types responsible for oral and anogenital cancers, but many circulating cancer-causing types remain for which vaccine coverage is lacking. In addition, all current HPV vaccines rely on aluminum salt-based adjuvant formulations that function through unclear mechanisms with few substitutes available. In an effort to expand the toolbox of available adjuvants suitable for HPV vaccines, we compared the immunogenicity of the RG1-VLP (virus-like particle) vaccine in BALB/c mice when formulated with either the aluminum hydroxide adjuvant Alhydrogel or the novel polyphosphazene macromolecular adjuvant poly[di (carboxylatoethylphenoxy) phosphazene] (PCEP). PCEP-formulated RG1-VLPs routinely outperformed VLP/Alhydrogel in several measurements of VLP-specific humoral immunity, including consistent improvements in the magnitude of antibody (Ab) responses to both HPV16-L1 and the L2 RG1 epitope as well as neutralizing titers to HPV16 and cross-neutralization of pseudovirion (PsV) types HPV18 and HPV39. Dose-sparing studies indicated that RG1-VLPs could be reduced in dose by 75% and the presence of PCEP ensured activity comparable to a full VLP dose adjuvanted by Alhydrogel. In addition, levels of HPV16-L1 and -L2-specific Abs were achieved after two vaccinations with PCEP as adjuvant that were equivalent to or greater than levels achieved with three vaccinations with Alhydrogel alone, indicating that the presence of PCEP resulted in accelerated immune responses that could allow for a decreased dose schedule. Given the extensive clinical track record of polyphosphazenes, these data suggest that substitution of alum-based adjuvants with PCEP for the RG1-VLP vaccine could lead to rapid seropositivity requiring fewer boosts, the dose-sparing of commercial VLP-based vaccines, and the establishment of longer-lasting humoral responses to HPV.

Expressed on cells of the myeloid and lymphoid lineages, V-domain Ig Suppressor of T cell Activation (VISTA) is an emerging target for cancer immunotherapy. Blocking VISTA activates both innate and adaptive immunity to eradicate tumors in mice. Using a tripeptide small molecule antagonist of VISTA CA170, we found that it exhibited potent anticancer efficacy on carcinogen-induced mouse lung tumorigenesis. Remarkably, lung tumor development was almost completely suppressed when CA170 was combined with an MHCII-directed KRAS peptide vaccine. Flow cytometry and single-cell RNA sequencing (scRNA-seq) revealed that CA170 increased CD8 + T cell infiltration and enhanced their effector functions by decreasing the tumor infiltration of myeloid-derived suppressor cells (MDSCs) and Regulatory T (Treg) cells, while the Kras vaccine primarily induced expansion of CD4 + effector T cells. VISTA antagonism by CA170 revealed strong efficacy against lung tumorigenesis with broad immunoregulatory functions that influence effector, memory and regulatory T cells, and drives an adaptive T cell tumor-specific immune response that enhances the efficacy of the KRAS vaccine., (© 2021. The Author(s).)

Poly[di(carboxylatomethylphenoxy)phosphazene] (PCMP), a new member of polyphosphazene immunoadjuvant family, is synthesized. In vitro assessment of a new macromolecule revealed hydrolytic degradation profile and immunostimulatory activity comparable to its clinical stage homologue PCPP; however, PCMP was characterized by a beneficial reduced sensitivity to the ionic environment. In vivo evaluation of PCMP potency was conducted with human papillomavirus (HPV) virus-like particles (VLPs) based RG1-VLPs vaccine. In contrast with previously reported self-assembly of polyphosphazene adjuvants with proteins, which typically results in the formation of complexes with multimeric display of antigens, PCMP surface modified VLPs in a composition dependent pattern, which at a high polymer-to VLPs ratio led to stabilization of antigenic particles. Immunization experiments in mice demonstrated that PCMP adjuvanted RG1-VLPs vaccine induced potent humoral immune responses, in particular, on the level of highly desirable protective cross-neutralizing antibodies, and outperformed PCPP and Alhydrogel adjuvanted formulations., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Patients with Lynch syndrome (LS) are at markedly increased risk for colorectal cancer. It is being increasingly recognised that the immune system plays an essential role in LS tumour development, thus making an ideal target for cancer prevention. Our objective was to evaluate the safety, assess the activity and discover novel molecular pathways involved in the activity of naproxen as primary and secondary chemoprevention in patients with LS., Design: We conducted a Phase Ib, placebo-controlled, randomised clinical trial of two dose levels of naproxen sodium (440 and 220 mg) administered daily for 6 months to 80 participants with LS, and a co-clinical trial using a genetically engineered mouse model of LS and patient-derived organoids (PDOs)., Results: Overall, the total number of adverse events was not different across treatment arms with excellent tolerance of the intervention. The level of prostaglandin E2 in the colorectal mucosa was significantly decreased after treatment with naproxen when compared with placebo. Naproxen activated different resident immune cell types without any increase in lymphoid cellularity, and changed the expression patterns of the intestinal crypt towards epithelial differentiation and stem cell regulation. Naproxen demonstrated robust chemopreventive activity in a mouse co-clinical trial and gene expression profiles induced by naproxen in humans showed perfect discrimination of mice specimens with LS and PDOs treated with naproxen and control., Conclusions: Naproxen is a promising strategy for immune interception in LS. We have discovered naproxen-induced gene expression profiles for their potential use as predictive biomarkers of drug activity., Trial Registration Number: gov Identifier: NCT02052908., Competing Interests: Competing interests: JS has a consulting role with Janssen Research and Development, and Cancer Prevention Pharmaceuticals. IW has an advisory role with Genentech/Roche, Bayer, Bristol-Myers Squibb, AstraZeneca/Medimmune, Pfizer, HTG Molecular, Asuragen, Merck, GlaxoSmithKline, Guardant Health and MSD, has received speaker fees from Medscape, MSD, Genentech/Roche, Pfizer and received research support from Genentech, Oncoplex, HTG Molecular, DepArray, Merck, Bristol-Myers Squibb, Medimmune, Adaptive, Adaptimmune, EMD Serono, Pfizer, Takeda, Amgen, Karus, Johnson & Johnson, Bayer, Iovance, 4D, Novartis, and Akoya. SL and EV are co-principal investigators in an NIH/NCI U01 award with co-investigators employed by Nouscom, s.r.l. EV has a consulting and advisory role with Janssen Research and Development and Recursion Pharma., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Current human papilloma virus (HPV) vaccines provide substantial protection against the most common HPV types responsible for oral and anogenital cancers, but many circulating cancer-causing types remain that lack vaccine coverage. The novel RG1-VLP (virus-like particle) vaccine candidate utilizes the HPV16-L1 subunit as a backbone to display an inserted HPV16-L2 17-36 a.a. "RG1" epitope; the L2 RG1 epitope is conserved across many HPV types and the generation of cross-neutralizing antibodies (Abs) against which has been demonstrated. In an effort to heighten the immunogenicity of the RG1-VLP vaccine, we compared in BALB/c mice adjuvant formulations consisting of novel bacterial enzymatic combinatorial chemistry (BECC)-derived toll-like receptor 4 (TLR4) agonists and the aluminum hydroxide adjuvant Alhydrogel. In the presence of BECC molecules, consistent improvements in the magnitude of Ab responses to both HPV16-L1 and the L2 RG1 epitope were observed compared to Alhydrogel alone. Furthermore, neutralizing titers to HPV16 as well as cross-neutralization of pseudovirion (PsV) types HPV18 and HPV39 were augmented in the presence of BECC agonists as well. Levels of L1 and L2-specific Abs were achieved after two vaccinations with BECC/Alhydrogel adjuvant that were equivalent to or greater than levels achieved with 3 vaccinations with Alhydrogel alone, indicating that the presence of BECC molecules resulted in accelerated immune responses that could allow for a decreased dose schedule for VLP-based HPV vaccines. In addition, dose-sparing studies indicated that adjuvantation with BECC/Alhydrogel allowed for a 75% reduction in antigen dose while still retaining equivalent magnitudes of responses to the full VLP dose with Alhydrogel. These data suggest that adjuvant optimization of HPV VLP-based vaccines can lead to rapid immunity requiring fewer boosts, dose-sparing of VLPs expensive to produce, and the establishment of a longer-lasting humoral immunity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The methods described here provide a standardized process for assessing in vitro tumor cell migration and invasion in real time. The kinetic data generated under these standardized conditions are reproducible and characteristic of individual tumor cell lines. The complex kinetic features of the data can be analyzed using parameters modeled after pharmacokinetic data processing. Application of the method to the array of tumor types included in the National Cancer Institute's sixty cell line panel (NCI60) revealed distinct modes of invasion with some tumor cell lines utilizing a mesenchymal mode and generating information-rich kinetic profiles. Other cell lines utilized an amoeboid mode not suitable for detection with this method. The method described will be useful as a guide for tumor cell line selection and as a starting point in designing experiments probing migration and invasion.

Cancer immunoprevention is achieved through promoting antitumor immune surveillance to block tumor formation and progression. Following the success of prophylactic vaccines against human papillomavirus (HPV) in preventing HPV-associated cancer, immunopreventive cancer vaccines targeting tumor antigens have been increasingly evaluated against cancers of noninfectious origin. While advances in cancer immunotherapy with immune checkpoint inhibitors (ICI) have clearly shown that the host immune system can mount effective antitumor immunity against tumor antigens when immune checkpoints are optimally blocked, the use of ICIs in the prevention setting has not been widely explored because of concerns of ICI-associated adverse events. In this issue of Cancer Prevention Research , Chung and colleagues demonstrate that the human cirrhotic liver harbors neoantigens, which accumulate further as the disease progresses to hepatocellular carcinoma (HCC), suggesting that cirrhotic liver may be susceptible to ICI therapy. Utilizing an established mouse model of carcinogen-induced liver fibrosis and HCC, they show that intermittent intervention by ICI, anti-mouse PD-1 (CD279) antibody, can prevent the progression of the precancerous stage of cirrhosis to HCC accompanied by increased T-cell infiltrates in the liver parenchyma. Importantly, there were no overt ICI-associated toxicities in the treated mice, indicating that safe dosing regimens could be established. This work is both significant and timely, opening the door to future studies, where the utility of ICI therapy can be further investigated not only in cirrhosis but other high-risk precancerous conditions. In this perspective, we discuss the implications of their findings, and the challenges and potential opportunities for use of ICIs for cancer immunoprevention. See related article by Chung et al., p. 911 ., (©2020 American Association for Cancer Research.)

In both estrogen receptor/progesterone receptor-positive (ER + /PR + ) human breast cancer and in ER + /PR + cancers in the methylnitrosourea (MNU)-induced rat model, short-term modulation of proliferation in early cancers predicts preventive/therapeutic efficacy. We determined the effects of known effective/ineffective chemopreventive agents on proliferative index (PI) in both rat mammary epithelium and small cancers. Female Sprague-Dawley rats were treated with MNU at 50 days of age. Five days later, the rats were treated with the individual compounds for a period of 14 days. At that time, normal mammary tissue from the inguinal gland area was surgically removed. After removal, the rats remained on the agents for an additional 5 months. This cancer prevention study confirmed our prior results of striking efficacy with tamoxifen, vorozole, Targretin, and gefitinib, and no efficacy with metformin, naproxen, and Lipitor. Employing a separate group of rats, the effects of short-term (7 days) drug exposure on small palpable cancers were examined. The PI in both small mammary cancers and in normal epithelium from control rats was >12%. In agreement with the cancer multiplicity data, tamoxifen, vorozole, gefitinib, and Targretin all strongly inhibited proliferation (>65%; P < 0.025) in the normal mammary epithelium. The ineffective agents metformin, naproxen, and Lipitor minimally affected PI. In the small cancers, tamoxifen, vorozole, and Targretin all reduced the PI, while metformin and Lipitor failed to do so. Thus, short-term changes in the PI in either normal mammary epithelium or small cancers correlated with long-term preventive efficacy in the MNU-induced rat model., (©2019 American Association for Cancer Research.)

Daily dosing of either NSAIDs or EGFR inhibitors has been shown to prevent bladder cancer development in a N-butyl-(4-hydroxybutyl)nitrosamine (OH-BBN)-induced rat model. However, these inhibitors cause gastrointestinal ulceration and acneiform rash, respectively, limiting their continuous use in a clinical prevention setting. We studied chemopreventive efficacy of pulsatile dosing of EGFR inhibitor erlotinib (42 mg/kg BW, once/week) combined with intermittent or continuous low doses of the NSAID naproxen (30 mg/kg BW/day, 3 weeks on/off or 128 ppm daily in diet) in the OH-BBN induced rat bladder cancer model. The interventions were started either at 1 or 4 weeks (early intervention) or 3 months (delayed intervention) after the last OH-BBN treatment, by which time the rats had developed microscopic bladder lesions. All combination regimens tested as early versus late intervention led to the reduction of the average bladder tumor weights (54%-82%; P < 0.01 to P < 0.0001), a decrease in tumor multiplicity (65%-85%; P < 0.01 to P < 0.0001), and a decrease in the number of rats with large palpable tumors (>200 mg; 83%-90%; P < 0.01 to P < 0.0001). Levels of signal transduction markers, Ki-67, cyclin D1, IL1β, pSTAT3, and pERK, were significantly ( P < 0.05 to P < 0.001) reduced in the treated tumors, demonstrating their potential utility as predictive markers for efficacy. These findings demonstrate that significant chemopreventive efficacy could be achieved with alternative intervention regimens designed to reduce the toxicity of agents, and that starting erlotinib and/or naproxen treatments at the time microscopic tumors were present still conferred the efficacy., (©2019 American Association for Cancer Research.)

Background: No effective approaches to target mutant Kras have yet been developed. Immunoprevention using KRAS-specific antigenic peptides to trigger T cells capable of targeting tumor cells relies heavily on lipid metabolism. To facilitate better TCR/peptide/MHC interactions that result in better cancer preventive efficacy, we combined KVax with avasimibe, a specific ACAT1 inhibitor, tested their anti-cancer efficacy in mouse lung cancer models, where Kras mutation was induced before vaccination., Methods: Control of tumor growth utilizing a multi-peptide Kras vaccine was tested in combination with avasimibe in a syngeneic lung cancer mouse model and a genetically engineered mouse model (GEMM). Activation of immune responses after administration of Kras vaccine and avasimibe was also assessed by flow cytometry, ELISpot and IHC., Findings: We found that Kras vaccine combined with avasimibe significantly decreased the presence of regulatory T cells in the tumor microenvironment and facilitated CD8+ T cell infiltration in tumor sites. Avasimibe also enhanced the efficacy of Kras vaccines target mutant Kras. Whereas the Kras vaccine significantly increased antigen-specific intracellular IFN-γ and granzyme B levels in CD8+ T cells, avasimibe significantly increased the number of tumor-infiltrating CD8+ T cells. Additionally, modulation of cholesterol metabolism was found to specifically impact in T cells, and not in cancer cells., Interpretation: Avasimibe complements the efficacy of a multi-peptide Kras vaccine in controlling lung cancer development and growth. This treatment regimen represents a novel immunoprevention approach to prevent lung cancer., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Signal transducer and activator of transcription 3 (STAT3) plays a key role in the transformation of normal cells to cancerous cells. Although inhibitors of STAT3 have been shown to suppress the growth of multiple cancer types in vitro and in vivo, such agents are of particular interest for the prevention of breast cancer, which affects over 200,000 women and claims more than 40,000 lives in the United States each year. In the present study, we employed the MMTV/Neu transgenic mouse model, which develops estrogen receptor (ER)‑negative, Neu‑overexpressing tumors, and the Sprague‑Dawley (SD) rat model, which develops ER‑positive tumors upon exposure to the carcinogen 7,12‑dimethylbenz[a]anthracene (DMBA), to test the efficacy of the STAT3 inhibitor GLG‑302 in the prevention of mammary cancer. Orally administered GLG‑302 and its trizma salt derivative reduced mammary cancer incidence, multiplicity, and tumor weights in female MMTV/Neu mice, and GLG‑302 reduced tumor multiplicity and weights in female DMBA‑treated rats. Consistent with the mechanism of action of STAT3 inhibitors, the reductions in mammary tumors were correlated with decreases in STAT3 phosphorylation and cell proliferation. These data suggest that GLG‑302 is a novel agent with potential for prevention of mammary cancer and support the further development of STAT3 inhibitors for this cause.

Background The hexapeptide 4A6 (Ac-Thr(tBu)-His(Bzl)-Thr(Bzl)-Nle-Glu(OtBu)-Gly-Bza) was isolated from a peptide library constructed to identify peptide-based transport inhibitors of multidrug resistance (MDR) efflux pumps including P-glycoprotein and Multidrug Resistance-associated Protein 1. 4A6 proved to be a substrate but not an inhibitor of these MDR efflux transporters. In fact, 4A6 and related peptides displayed potent cytotoxic activity via an unknown mechanism. Objective To decipher the mode of cytotoxic activity of 4A6. Methods Screening of 4A6 activity was performed against the NCI60 panel of cancer cell lines. Possible interactions of 4A6 with the 26S proteasome were assessed via proteasome activity and affinity labeling, and cell growth inhibition studies with leukemic cells resistant to the proteasome inhibitor bortezomib (BTZ). Results The NCI60 panel COMPARE analysis revealed that 4A6 had an activity profile overlapping with BTZ. Consistently, 4A6 proved to be a selective and reversible inhibitor of β5 subunit (PSMB5)-associated chymotrypsin-like activity of the 26S proteasome. This conclusion is supported by several lines of evidence: (i) inhibition of chymotrypsin-like proteasome activity by 4A6 and related peptides correlated with their cell growth inhibition potencies; (ii) 4A6 reversibly inhibited functional β5 active site labeling with the affinity probe BodipyFL-Ahx 3 L 3 VS; and (iii) human myeloid THP1 cells with acquired BTZ resistance due to mutated PSMB5 were highly (up to 287-fold) cross-resistant to 4A6 and its related peptides. Conclusion 4A6 is a novel specific inhibitor of the β5 subunit-associated chymotrypsin-like proteasome activity. Further exploration of 4A6 as a lead compound for development as a novel proteasome-targeted drug is warranted.

Because of the importance of testing reproducibility of results, we present our findings regarding screening agents in preclinical chemoprevention studies in rodent models performed by the Chemopreventive Agent Development Research Group (CADRG) of the Division of Cancer Prevention of the NCI. These studies were performed via contracts to various commercial and academic laboratories. Primarily, results with positive agents are reported because positive agents may progress to the clinics. In testing reproducibility, a limited number of direct repeats of our standard screening assays were performed; which entailed initiating treatment shortly after carcinogen administration or in young transgenic mice and continuing treatment until the end of the study. However, three additional protocols were employed relating to reproducibility: (i) testing agents at lower doses to determine efficacy and reduced toxicity; (ii) testing agents later in tumor progression when microscopic lesions existed and, (iii) testing multiple agents of the same mechanistic class. Data with six models that were routinely employed are presented: MNU-induced ER-positive mammary cancer in rats; MMTV-Neu ER-negative mammary cancers in transgenic mice; AOM-induced colon tumors in rats; intestinal adenomas in Min mice; OH-BBN-induced invasive rat urinary bladder cancers in rats; and UV-induced skin squamous carcinomas in mice. It was found that strongly positive results were highly reproducible in the preclinical models evaluated. Cancer Prev Res; 11(10); 595-606. ©2018 AACR ., (©2018 American Association for Cancer Research.)

Lung cancer remains the leading cause of cancer death worldwide. Mutations in KRAS are detected in up to 30% of lung cancer cases. No effective therapies specifically targeting mutant KRAS have been developed. Vaccination against KRAS mutants is one of the venues of active exploration. The present study evaluated both immunogenicity and antitumor efficacy of a newly formulated multipeptide vaccine targeting multiple epitopes of the KRAS molecule. The formulated vaccine contained top four peptides, which elicited the strongest immunologic response and showed 100% sequence homology between human and mouse. The multipeptide KRAS vaccine was tested in an inducible CCSP-TetO-KRAS G12D mouse model, where the vaccine was administered prior to activating the mutant KRAS protein. The KRAS peptide vaccine exhibited striking efficacy, reducing tumor number and tumor burden by >80% when compared with adjuvant alone. Splenocytes collected from vaccinated animals showed a robust immunologic response to the immunizing peptides. Furthermore, in vitro stimulation of these splenocytes by the vaccinated peptides resulted in the secretion of cytokines indicative of Th1 responses but with minimal secretion of Th2-related cytokines. The multipeptide KRAS vaccine was immunogenic and efficacious in the primary prevention of KRAS-induced lung cancer, indicating that the approach potentially can be used to prevent other KRAS-driven cancers, either alone or in combination with other modalities., Competing Interests: CONFLICTS OF INTEREST No potential conflicts of interest were disclosed by any authors of this manuscript.

Primary effusion lymphoma (PEL) is a largely incurable malignancy of B cell origin with plasmacytic differentiation. Here, we report the identification of a highly effective inhibitor of PEL. This compound, 6-ethylthioinosine (6-ETI), is a nucleoside analog with toxicity to PEL in vitro and in vivo, but not to other lymphoma cell lines tested. We developed and performed resistome analysis, an unbiased approach based on RNA sequencing of resistant subclones, to discover the molecular mechanisms of sensitivity. We found different adenosine kinase-inactivating (ADK-inactivating) alterations in all resistant clones and determined that ADK is required to phosphorylate and activate 6-ETI. Further, we observed that 6-ETI induces ATP depletion and cell death accompanied by S phase arrest and DNA damage only in ADK-expressing cells. Immunohistochemistry for ADK served as a biomarker approach to identify 6-ETI-sensitive tumors, which we documented for other lymphoid malignancies with plasmacytic features. Notably, multiple myeloma (MM) expresses high levels of ADK, and 6-ETI was toxic to MM cell lines and primary specimens and had a robust antitumor effect in a disseminated MM mouse model. Several nucleoside analogs are effective in treating leukemias and T cell lymphomas, and 6-ETI may fill this niche for the treatment of PEL, plasmablastic lymphoma, MM, and other ADK-expressing cancers.

The PREVENT Cancer Preclinical Drug Development Program (PREVENT) is a National Cancer Institute, Division of Cancer Prevention (NCI, DCP)-supported program whose primary goal is to bring new cancer preventive interventions (small molecules and vaccines) and biomarkers through preclinical development towards clinical trials by creating partnerships between the public sector (eg, academia, industry) and DCP. PREVENT has a formalized structure for moving interventions forward in the prevention pipeline using a stage-gate process with go/no go decision points along the critical path for development. This review describes the structure of the program, its focus areas, and provides examples of projects currently in the pipeline., (Published by Elsevier Inc.)