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Background PD-1 inhibitors have shown significant efficacy in triple negative breast cancer (BC), however, durable responses are less common in estrogen receptor-positive (ER+) BC. Better markers are therefore needed that will identify likely responders to PD-1 inhibitors among patients with luminal BC. While most efforts have focused on the immune checkpoint protein PD-L1, the alternative PD-1 ligand, PD-L2, has been largely overlooked. We aimed to determine if PD-L2 is associated with unfavorable prognosis in ER+ BC. Methods PD-L2 protein levels in cancer cells and stromal cells were measured retrospectively by quantitative immunofluorescence histocytometry in tissue microarrays of therapy-naïve, localized or locoregional ER+ BC and correlated with progression-free survival (PFS). Evaluable tumor PD-L2 data were derived from a main study cohort A diagnosed between 1988-2005 (n=684) with extensive clinical and outcome data and from an independent validation cohort B diagnosed between 1992-2012 (n=273). Patients received standard-of-care adjuvant therapy without immune checkpoint inhibitors after tumor resection. Results Univariate analysis of the main cohort A revealed that high PD-L2 expression in cancer cells was associated with shorter PFS (HR=1.8; 95%CI:1.3-2.6; p=0.001), an observation that was validated in an independent cohort B (HR=2.3, 95%CI:1.1-4.8; p=0.026). Approximately one third of ER+ BC cases were classified as high PD-L2. After multivariable adjustment for common clinicopathological variables, high cancer cell levels of PD-L2 remained independently predictive of early recurrence (HR=2.0; 95%CI:1.4-2.9; p< 0.001). Sub-analysis of ER+ BC cases treated with adjuvant chemotherapy (n=197) suggested that high PD-L2 levels in cancer cells was associated with particularly increased risk of progression (multivariable HR=3.4; 95%CI:1.9-6.2; p< 0.001). The observed frequent expression of PD-L2 protein in BC provided scientific rationale for the design of our ongoing phase II clinical trial (NCT04243616) of neoadjuvant combined PD-1 inhibitor (cemiplimab; Regeneron Pharmaceuticals Inc) and chemotherapy in patients diagnosed with PD-L1+ and/or PD-L2+ BC. The primary objective of this trial is to assess pathologic responses to neoadjuvant treatment with secondary objective of assessing the correlation between PD-L1/PD-L2 status and tumor responses. Pathologist review of PD-L1 and PD-L2 expression in an initial set of ER+ tumors (n=15) screened for trial eligibility revealed frequent discordance between cancer cell positivity for PD-L1 and PD-L2 protein (PD-L1: median=0%; range 0-2% vs. PD-L2: median=18%; range < 1-60%) as well as immune cell positivity (PD-L1: median=5%; range 0-50% vs. PD-L2: median=0; range 0-50%). Conclusions In treatment-naïve ER+ breast tumors, high cancer cell expression of PD-L2 protein was an independent predictor of poor clinical outcome, with evidence of further elevated risk of progression in patients who received adjuvant chemotherapy. Preliminary analyses of ER+ tumors from our ongoing clinical trial showed frequent discordance between baseline PD-L1 and PD-L2 protein expression in both cancer cells and immune cells. Collectively, our analyses indicate that PD-L2 has prognostic value for ER+ BC, and our progress justify further studies to determine whether PD-L2, alone or in combination with PD-L1, may serve as a predictive marker of response to PD-1 inhibitors. Citation Format: Lubna N. Chaudhary, Inna Chervoneva, Amy R. Peck, Yunguang Sun, Misung Yi, John F. Langenheim, Julie M. Jorns, Sailaja Kamaraju, Yee Chung Cheng, John Burfeind, Christopher R. Chitambar, Jeffrey A. Hooke, Albert J. Kovatich, Craig Shriver, Hai Hu, Juan P. Palazzo, Marluce Bibbo, Terry Hyslop, Richard Pestell, Edith P. Mitchell, Hallgeir Rui. High PD-L2 Protein Expression in Cancer Cells is an Independent Marker of Unfavorable Prognosis in Luminal Breast Tumors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-13.

Background. Endocrine resistant metastatic disease develops in ~20-25% of hormone-receptor positive (HR+) breast cancer (BC) patients despite endocrine therapy (ET) use. Upregulation of HER family receptor tyrosine kinases (RTKs) represent escape mechanisms in response to ET in some HR+ tumors. Short-term neoadjuvant ET (NET) offers the opportunity to identify early endocrine escape mechanisms initiated in individual tumors. Methods. This was a single arm, interventional phase II clinical trial evaluating 4 weeks (+/-1 week) of NET in patients with early-stage HR+/HER2-negative (HER2-) BC. The primary objective was to assess NET-induced changes in HER1-4 proteins by immunohistochemistry (IHC) score. Protein upregulation was defined as an increase of ≥1 in IHC score following NET. Results. Thirty-seven patients with cT1-T3, cN0, HR+/HER2- BC were enrolled. In 35 patients with evaluable tumor HER protein after NET, HER2 was upregulated in 48.6% (17/35; p=0.025), with HER2-positive status (IHC 3+ or FISH-amplified) detected in three patients at surgery, who were recommended adjuvant trastuzumab-based therapy. Downregulation of HER3 and/or HER4 protein was detected in 54.2% of tumors, whereas HER1 protein remained low and unchanged in all cases. While no significant volumetric reduction was detected radiographically after short-term NET, significant reduction in tumor proliferation rates were observed. No significant associations were identified between any clinicopathologic covariates and changes in HER1-4 protein expression on multivariable analysis. Conclusion. Short-term NET frequently and preferentially upregulates HER2 over other HER-family RTKs in early-stage HR+/HER2- BC and may be a promising strategy to identify tumors that utilize HER2 as an early endocrine escape pathway. Trial registration number: NCT03219476 Date of registration for prospectively registered trials: July 17, 2017

PDF File - 501K, PF02341066 is well tolerated in female athymic nude mice.

Supplementary figure 1 with 4 panels of images

PDF File - 57K, Legends for Supplementary Figures 1-3.

Insulin-like growth factor binding protein 3 (IGFBP3) modulates cell growth through IGF-dependent and -independent mechanisms. Reports suggest that the serum levels of IGFBP3 are associated with various cancers and that IGFBP3 expression is significantly decreased in cisplatin (CDDP)-resistant lung cancer cells. Based on these findings, we investigated whether Igfbp3 deficiency accelerates mouse lung tumorigenesis and if expression of IGFBP3 enhances CDDP response by focusing on the IGF1 signaling cascade. To this end, an Igfbp3-null mouse model was generated in combination with KrasG12D to compare the tumor burden. Then, IGF-dependent signaling was assessed after expressing wild-type or a mutant IGFBP3 without IGF binding capacity in non–small cell lung cancer (NSCLC) cells. Finally, the treatment response to CDDP chemotherapy was evaluated under conditions of IGFBP3 overexpression. Igfbp3-null mice had increased lung tumor burden (>2-fold) and only half of human lung cancer cells survived after expression of IGFBP3, which corresponded to increased cleaved caspase-3 (10-fold), inactivation of IGF1 and MAPK signaling. In addition, overexpression of IGFBP3 increased susceptibility to CDDP treatment in lung cancer cells. These results, for the first time, demonstrate that IGFBP3 mediates lung cancer progression in a KrasG12D mouse model. Furthermore, overexpression of IGFBP3 induced apoptosis and enhanced cisplatin response in vitro and confirmed that the suppression is in part by blocking IGF1 signaling.Implications: These findings reveal that IGFBP3 is effective in lung cancer cells with high IGF1 signaling activity and imply that relevant biomarkers are essential in selecting lung cancer patients for IGF1-targeted therapy. Mol Cancer Res; 15(7); 896–904. ©2017 AACR.

Supplementary Figure 7: Schematic representation of structure of wildtype Stat5a and Stat5b, dominant-negative Stat5 (DN-Stat5) and constitutively-active Stat5 (CA-Stat5) proteins.

Combined Supplementary Figures, Supplementary Tables, Legends and Key Resource Tables

Clinical Characteristics of Outcome Cohorts 1 and 2.

Supplementary Material-1. Heatmap shows all the known ligand-receptor interactions between different cell types identified by CellPhoneDB in the OvD5-SS2 dataset.

SupplementaryMethods.docx from Oncostatin M Receptor–Targeted Antibodies Suppress STAT3 Signaling and Inhibit Ovarian Cancer Growth

Purpose:Parathyroid hormone-related protein (PTHrP) is required for normal mammary gland development and biology. A PTHLH gene polymorphism is associated with breast cancer risk, and PTHrP promotes growth of osteolytic breast cancer bone metastases. Accordingly, current dogma holds that PTHrP is upregulated in malignant primary breast tumors, but solid evidence for this assumption is missing.Experimental Design:We used quantitative IHC to measure PTHrP in normal and malignant breast epithelia, and correlated PTHrP levels in primary breast cancer with clinical outcome.Results:PTHrP levels were markedly downregulated in malignant compared with normal breast epithelia. Moreover, low levels of nuclear localized PTHrP in cancer cells correlated with unfavorable clinical outcome in a test and a validation cohort of breast cancer treated at different institutions totaling nearly 800 cases. PTHrP mRNA levels in tumors of a third cohort of 737 patients corroborated this association, also after multivariable adjustment for standard clinicopathologic parameters. Breast cancer PTHrP levels correlated strongly with transcription factors Stat5a/b, which are established markers of favorable prognosis and key mediators of prolactin signaling. Prolactin stimulated PTHrP transcript and protein in breast cancer cell lines in vitro and in vivo, effects mediated by Stat5 through the P2 gene promoter, producing transcript AT6 encoding the PTHrP 1-173 isoform. Low levels of AT6, but not two alternative transcripts, correlated with poor clinical outcome.Conclusions:This study overturns the prevailing view that PTHrP is upregulated in primary breast cancers and identifies a direct prolactin–Stat5–PTHrP axis that is progressively lost in more aggressive tumors.

Although patients with advanced ovarian cancer may respond initially to treatment, disease relapse is common, and nearly 50% of patients do not survive beyond five years, indicating an urgent need for improved therapies. To identify new therapeutic targets, we performed single-cell and nuclear RNA-seq data set analyses on 17 human ovarian cancer specimens, revealing the oncostatin M receptor (OSMR) as highly expressed in ovarian cancer cells. Conversely, oncostatin M (OSM), the ligand of OSMR, was highly expressed by tumor-associated macrophages and promoted proliferation and metastasis in cancer cells. Ovarian cancer cell lines and additional patient samples also exhibited elevated levels of OSMR when compared with other cell types in the tumor microenvironment or to normal ovarian tissue samples. OSMR was found to be important for ovarian cancer cell proliferation and migration. Binding of OSM to OSMR caused OSMR–IL6ST dimerization, which is required to produce oncogenic signaling cues for prolonged STAT3 activation. Human monoclonal antibody clones B14 and B21 directed to the extracellular domain of OSMR abrogated OSM-induced OSMR–IL6ST heterodimerization, promoted the internalization and degradation of OSMR, and effectively blocked OSMR-mediated signaling in vitro. Importantly, these antibody clones inhibited the growth of ovarian cancer cells in vitro and in vivo by suppressing oncogenic signaling through OSMR and STAT3 activation. Collectively, this study provides a proof of principle that anti-OSMR antibody can mediate disruption of OSM-induced OSMR–IL6ST dimerization and oncogenic signaling, thus documenting the preclinical therapeutic efficacy of human OSMR antagonist antibodies for immunotherapy in ovarian cancer.Significance:This study uncovers a role for OSMR in promoting ovarian cancer cell proliferation and metastasis by activating STAT3 signaling and demonstrates the preclinical efficacy of antibody-based OSMR targeting for ovarian cancer treatment.

Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. The DACH1 gene encodes a winged helix/Forkhead DNA-binding protein that competes for binding to FOXM1 sites. Herein, DACH1 gene deletion within the 13q21.31-q21.33 region occurs in up to 18% of human PCa and was associated with increased AR activity and poor prognosis. In prostate OncoMice, prostate-specific deletion of the Dach1 gene enhanced prostatic intraepithelial neoplasia (PIN), and was associated with increased TGFb activity and DNA damage. Reduced Dach1 increased DNA damage in response to genotoxic stresses. DACH1 was recruited to sites of DNA damage, augmenting recruitment of Ku70/Ku80. Reduced Dach1 expression was associated with increased homology directed repair and resistance to PARP inhibitors and TGFb kinase inhibitors. Reduced Dach1 expression may define a subclass of PCa that warrants specific therapies.

PURPOSE T-cell–mediated cytotoxicity is suppressed when programmed cell death-1 (PD-1) is bound by PD-1 ligand-1 (PD-L1) or PD-L2. Although PD-1 inhibitors have been approved for triple-negative breast cancer, the lower response rates of 25%-30% in estrogen receptor–positive (ER+) breast cancer will require markers to identify likely responders. The focus of this study was to evaluate whether PD-L2, which has higher affinity than PD-L1 for PD-1, is a predictor of early recurrence in ER+ breast cancer. METHODS PD-L2 protein levels in cancer cells and stromal cells of therapy-naive, localized or locoregional ER+ breast cancers were measured retrospectively by quantitative immunofluorescence histocytometry and correlated with progression-free survival (PFS) in the main study cohort (n = 684) and in an independent validation cohort (n = 273). All patients subsequently received standard-of-care adjuvant therapy without immune checkpoint inhibitors. RESULTS Univariate analysis of the main cohort revealed that high PD-L2 expression in cancer cells was associated with shorter PFS (hazard ratio [HR], 1.8; 95% CI, 1.3 to 2.6; P = .001), which was validated in an independent cohort (HR, 2.3; 95% CI, 1.1 to 4.8; P = .026) and remained independently predictive after multivariable adjustment for common clinicopathological variables (HR, 2.0; 95% CI, 1.4 to 2.9; P < .001). Subanalysis of the ER+ breast cancer patients treated with adjuvant chemotherapy (n = 197) revealed that high PD-L2 levels in cancer cells associated with short PFS in univariate (HR, 2.5; 95% CI, 1.4 to 4.4; P = .003) and multivariable analyses (HR, 3.4; 95% CI, 1.9 to 6.2; P < .001). CONCLUSION Up to one third of treatment-naive ER+ breast tumors expressed high PD-L2 levels, which independently predicted poor clinical outcome, with evidence of further elevated risk of progression in patients who received adjuvant chemotherapy. Collectively, these data warrant studies to gain a deeper understanding of PD-L2 in the progression of ER+ breast cancer and may provide rationale for immune checkpoint blockade for this patient group.

The essential G1-cyclin, CCND1, is a collaborative nuclear oncogene that is frequently overexpressed in cancer. D-type cyclins bind and activate CDK4 and CDK6 thereby contributing to G1–S cell-cycle progression. In addition to the nucleus, herein cyclin D1 was also located in the cytoplasmic membrane. In contrast with the nuclear-localized form of cyclin D1 (cyclin D1NL), the cytoplasmic membrane-localized form of cyclin D1 (cyclin D1MEM) induced transwell migration and the velocity of cellular migration. The cyclin D1MEM was sufficient to induce G1–S cell-cycle progression, cellular proliferation, and colony formation. The cyclin D1MEM was sufficient to induce phosphorylation of the serine threonine kinase Akt (Ser473) and augmented extranuclear localized 17β-estradiol dendrimer conjugate (EDC)-mediated phosphorylation of Akt (Ser473). These studies suggest distinct subcellular compartments of cell cycle proteins may convey distinct functions.

Within the microenvironment of solid tumors, stress associated with deficit of nutrients and oxygen as well as tumor-derived factors triggers the phosphorylation-dependent degradation of the IFNAR1 chain of type I interferon (IFN1) receptor and ensuing suppression of the IFN1 pathway. Here we sought to examine the importance of these events in malignant mammary cells. Expression of non-degradable IFNAR1(S526A) mutant in mouse mammary adenocarcinoma cells stimulated the IFN1 pathway yet did not affect growth of these cells in vitro or ability to form subcutaneous tumors in the syngeneic mice. Remarkably, these cells exhibited a notably accelerated growth when transplanted orthotopically into mammary glands. Importantly, in human patients with either ER+ or ER- breast cancers, high levels of IFNAR1 were associated with poor prognosis. We discuss the putative mechanisms underlying the pro-tumorigenic role of IFNAR1 in malignant breast cells.

Background: Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. The DACH1 gene encodes a winged helix/Forkhead DNA-binding protein that competes for binding to FOXM1 sites. Methods: Analysis of DACH1 gene deletion and gene expression was conducted from public data bases and human prostate cancer samples. Transgenic mice were generated in which the Dach1 gene was deleted in the prostate of prostate Oncomice. Cells derived from Dach1 gene deletion mice and human prostate cancer cell lines with Dach1 knockdown were analyzed for DNA damage repair responses. Results: DACH1 gene deletion within the 13q21.31-q21.33 region, occurred in up to 18% of human PCa, and was associated with increased AR activity, and poor prognosis. DACH1 homozygous deletions more frequent in the metastatic site than in the primary tumors (Mich: 10% vs. 18%, N=59; FHCRC: 4% vs.11%, N= 54, SU2C: not profiled vs. 3.3, N=150). The prevalence of DACH1 heterozygous deletions was higher in the metastatic lesions than in primary tumors within a given cohort for three of six cohorts (Mich: 27.3% vs. 36%, N=59; FHCRC: 15% vs. 59%, N=54; SU2C: 0% vs. 26%, N=150, respectively). The patients with homozygous DACH1 deletions had reduced overall survival (medians of 84 vs. 120 months, N=667, log rank test P=9.3x10-3). Low DACH1 gene expression (expressed as a z-score with a z-score threshold of -1.25) was significantly correlated with earlier biochemical recurrence (BCR, log rank p value = 4.7x10-4, n=79). In prostate OncoMice, prostate-specific deletion of the Dach1 gene enhanced prostatic intraepithelial neoplasia (PIN) and was associated with increased DNA damage. Reduced Dach1 increased DNA damage in responses to genotoxic stresses. DACH1 was recruited to sites of DNA damage, augmenting recruitment of Ku70/Ku80. Reduced Dach1 expression was associated with resistance to TGFβ kinase and PARP inhibitors. Conclusions: Reduced Dach1 expression may define a subclass of PCa that warrants specific therapies. Citation Format: Zhiping Li, Xuanmao Jiao, Gordon Robertson, Gabriele Di Sante, Anthony W. Ashton, Agnese DiRocco, Min Wang, Jun Zhao, Sankar Addya, Chenguang Wang, Peter A. McCue, Andrew P. South, Carlos Cordon-Cardo, Runzhi Liu, Kishan Patel, Rasha Hamid, Jorim Parmar, James B. DuHadaway, Nikolaus Schultz, Andrew Kossenkov, Lai Yee Phoon, Hao Chen, Li Lan, Yunguang Sun, Kenneth A. Iczkowski, Hallgeir Rui, Richard G. Pestell. The DACH1 gene is frequently deleted in prostate cancer, restrains prostatic intraepithelial neoplasia, augments DNA damage repair and predicts therapy responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2598.

Simple Summary A majority of breast cancer deaths are caused by aggressive molecular subtypes that are at high risk of progression. Patients with high-risk breast cancer commonly receive first-line systemic chemotherapy. Chemotherapy exerts direct cytotoxic effects on proliferating cancer cells. In addition, significant effects of chemotherapy are mediated through immune-boosting anti-cancer mechanisms that counteract immunosuppressive tumor-associated macrophages (TAMs). The aim of our study was to evaluate the potential prognostic value of the prevalence and the spatial localization of CD163+ TAMs in tumor tissue from breast cancer patients treated with chemotherapy after surgery. We developed a novel algorithm that identifies CD163+ TAMs in an objective manner and quantifies spatial interactions between CD163+ TAMs and cancer cells using distance-based metrics. Our results demonstrate that close spatial proximity of CD163+ TAMs to cancer cells and the average number of CD163+ cells either directly adjacent to or within communicating distance of each cancer cell are independent predictors of unfavorable prognosis in breast cancer. Abstract Tumor-associated macrophages (TAMs) promote progression of breast cancer and other solid malignancies via immunosuppressive, pro-angiogenic and pro-metastatic effects. Tumor-promoting TAMs tend to express M2-like macrophage markers, including CD163. Histopathological assessments suggest that the density of CD163-positive TAMs within the tumor microenvironment is associated with reduced efficacy of chemotherapy and unfavorable prognosis. However, previous analyses have required research-oriented pathologists to visually enumerate CD163+ TAMs, which is both laborious and subjective and hampers clinical implementation. Objective, operator-independent image analysis methods to quantify TAM-associated information are needed. In addition, since M2-like TAMs exert local effects on cancer cells through direct juxtacrine cell-to-cell interactions, paracrine signaling, and metabolic factors, we hypothesized that spatial metrics of adjacency of M2-like TAMs to breast cancer cells will have further information value. Immunofluorescence histo-cytometry of CD163+ TAMs was performed retrospectively on tumor microarrays of 443 cases of invasive breast cancer from patients who subsequently received adjuvant chemotherapy. An objective and automated algorithm was developed to phenotype CD163+ TAMs and calculate their density within the tumor stroma and derive several spatial metrics of interaction with cancer cells. Shorter progression-free survival was associated with a high density of CD163+ TAMs, shorter median cancer-to-CD163+ nearest neighbor distance, and a high number of either directly adjacent CD163+ TAMs (within juxtacrine proximity

PURPOSE: Understanding the molecular mediators of breast cancer survival is critical for accurate disease prognosis and improving therapies. Here, we identified Neuronatin (NNAT) as a novel antiproliferative modifier of estrogen receptor-alpha (ER+) breast cancer. EXPERIMENTAL DESIGN: Genomic regions harboring breast cancer modifiers were identified by congenic mapping in a rat model of carcinogen-induced mammary cancer. Tumors from susceptible and resistant congenics were analyzed by RNAseq to identify candidate genes. Candidates were prioritized by correlation with outcome, using a consensus of three breast cancer patient cohorts. NNAT was transgenically expressed in ER+ breast cancer lines (T47D and ZR75), followed by transcriptomic and phenotypic characterization. RESULTS: We identified a region on rat chromosome 3 (142–178 Mb) that modified mammary tumor incidence. RNAseq of the mammary tumors narrowed the candidate list to three differentially expressed genes: NNAT, SLC35C2, and FAM210B. NNAT mRNA and protein also correlated with survival in human breast cancer patients. Quantitative immunohistochemistry of NNAT protein revealed an inverse correlation with survival in a univariate analysis of patients with invasive ER+ breast cancer (training cohort: n = 444, HR = 0.62, p = 0.031; validation cohort: n = 430, HR = 0.48, p = 0.004). NNAT also held up as an independent predictor of survival after multivariable adjustment (HR = 0.64, p = 0.038). NNAT significantly reduced proliferation and migration of ER+ breast cancer cells, which coincided with altered expression of multiple related pathways. CONCLUSIONS: Collectively, these data implicate NNAT as a novel mediator of cell proliferation and migration, which correlates with decreased tumorigenic potential and prolonged patient survival.

Most breast cancer deaths are caused by estrogen receptor-α–positive (ER+) disease. Preclinical progress is hampered by a shortage of therapy-naive ER+ tumor models that recapitulate metastatic pro...

Although patients with advanced ovarian cancer may respond initially to treatment, disease relapse is common, and nearly 50% of patients do not survive beyond five years, indicating an urgent need for improved therapies. To identify new therapeutic targets, we performed single-cell and nuclear RNA-seq data set analyses on 17 human ovarian cancer specimens, revealing the oncostatin M receptor (OSMR) as highly expressed in ovarian cancer cells. Conversely, oncostatin M (OSM), the ligand of OSMR, was highly expressed by tumor-associated macrophages and promoted proliferation and metastasis in cancer cells. Ovarian cancer cell lines and additional patient samples also exhibited elevated levels of OSMR when compared with other cell types in the tumor microenvironment or to normal ovarian tissue samples. OSMR was found to be important for ovarian cancer cell proliferation and migration. Binding of OSM to OSMR caused OSMR–IL6ST dimerization, which is required to produce oncogenic signaling cues for prolonged STAT3 activation. Human monoclonal antibody clones B14 and B21 directed to the extracellular domain of OSMR abrogated OSM-induced OSMR–IL6ST heterodimerization, promoted the internalization and degradation of OSMR, and effectively blocked OSMR-mediated signaling in vitro. Importantly, these antibody clones inhibited the growth of ovarian cancer cells in vitro and in vivo by suppressing oncogenic signaling through OSMR and STAT3 activation. Collectively, this study provides a proof of principle that anti-OSMR antibody can mediate disruption of OSM-induced OSMR–IL6ST dimerization and oncogenic signaling, thus documenting the preclinical therapeutic efficacy of human OSMR antagonist antibodies for immunotherapy in ovarian cancer. Significance: This study uncovers a role for OSMR in promoting ovarian cancer cell proliferation and metastasis by activating STAT3 signaling and demonstrates the preclinical efficacy of antibody-based OSMR targeting for ovarian cancer treatment.

Vaccinations are widely credited with reducing death rates from COVID-19 but the underlying host-viral mechanisms/interactions for morbidity and mortality of SARS-CoV-2 infection remain poorly understood. Acute respiratory distress syndrome (ARDS) describes the severe lung injury, which is pathologically associated with alveolar damage, inflammation, non-cardiogenic edema, and hyaline membrane formation. Because proteostatic pathways play central roles in cellular protection, immune modulation, protein degradation and tissue repair, we examined the pathological features for the unfolded protein response (UPR) using the surrogate biomarker glucose regulated protein 78 (GRP78) and co-receptor for SARS-CoV-2. At autopsy, immunostaining of COVID-19 lungs showed highly elevated expression of GRP78 in both pneumocytes and macrophages compared to non-COVID control lungs. GRP78 expression was detected in both SARS-CoV-2 infected and un-infected pneumocytes as determined by multiplexed immunostaining for nucleocapsid protein. In macrophages, immunohistochemical staining for GRP78 from deceased COVID-19 patients was increased but overlapped with GRP78 expression taken from surgical resections of non-COVID-19 controls. In contrast, the robust in situ GRP78 immunostaining of pneumocytes from COVID-19 autopsies exhibited no overlap and was independent of age, race/ethnicity and gender compared with non-COVID-19 controls. Our findings bring new insights for stress-response pathways involving the proteostatic network implicated for host resilience and suggest that targeting of GRP78 expression might afford an alternative therapeutic strategy to modulate host-viral interactions during SARS-CoV-2 infections.

The aim of the present study was to explore the safety of apatinib plus S-1 in treating advanced solid tumors after failure of two or more lines of chemotherapy. A total of 33 patients with advanced cancer treated between April 2016 to March 2019 were retrospectively analyzed. Of these, 13 patients had non-small cell lung cancer (NSCLC), 13 patients had SCLC, 4 patients had esophageal cancer and 3 had cervical cancer. All patients were treated with apatinib 250 mg once daily combined with S-1 60 mg/m2 twice daily for 14 days, repeated every 3 weeks. Adverse reactions were observed until aggravation of adverse reactions beyond the tolerable range or disease progression, and the survival rate and clinical benefits were calculated. The results suggested that the incidence rate of adverse effects (grade 3-4) was 45.5% (15/33). The top three severe adverse effects were hypertension (15.2%), thrombocytopenia (12.1%) and proteinuria (9.1%). A total of 2 patients with lung squamous-cell carcinomas died of severe pulmonary hemorrhage. Other adverse reactions were tolerated in the cohort. A total of 10 patients achieved partial response and the objective response rate was 30.3%. Furthermore, 13 patients achieved stable disease and 10 patients had progressive disease, and accordingly, the disease control rate was 72.7%. In conclusion, apatinib plus S-1 for advanced solid tumor patients as palliative treatment have a certain efficacy and was relatively safe but should be used with caution in patients with squamous-cell lung carcinoma and the efficacy and safety requires further assessment.

SUMMARY Fragile X-related protein-1 (FXR1) gene is highly amplified in patients with ovarian cancer, and this amplification is associated with increased expression of both FXR1 mRNA and protein. FXR1 expression directly associates with the survival and proliferation of cancer cells. Surface sensing of translation (SUnSET) assay demonstrates that FXR1 enhances the overall translation in cancer cells. Reverse-phase protein array (RPPA) reveals that cMYC is the key target of FXR1. Mechanistically, FXR1 binds to the AU-rich elements (ARE) present within the 3′ untranslated region (3′UTR) of cMYC and stabilizes its expression. In addition, the RGG domain in FXR1 interacts with eIF4A1 and eIF4E proteins. These two interactions of FXR1 result in the circularization of cMYC mRNA and facilitate the recruitment of eukaryotic translation initiation factors to the translation start site. In brief, we uncover a mechanism by which FXR1 promotes cMYC levels in cancer cells., Graphical abstract, In brief George et al. demonstrate that FXR1 binds to the AREs within the 3′UTR of MYC mRNA and improves its stability. The authors also show that the RGG domain of FXR1 interacts with eIF4A1 and eIF4E and facilitates recruitment of the eIF4F complex to translation initiation sites for cMYC translation.

BackgroundThe RNA-binding protein FXR1 (fragile X-related protein 1) has been implicated as an important regulator of post-transcriptional changes of mRNAs. However, its role in mRNA circularization and recruitment of eukaryotic translation initiation factors for protein translation remains obscure. Here, we aimed to investigate the molecular mechanisms and potential clinical applications of FXR1 in ovarian cancer growth and progression.MethodsFXR1 copy number variation, mRNA expression, protein levels, and their association with prognosis were determined in clinical datasets. An orthotopic ovarian cancer model and bioluminescence imaging were used for preclinical evaluation of FXR1 in vivo. Reverse phase protein arrays (RPPA) and qPCR arrays were performed to identify FXR1’s key targets and downstream effects. SUnSET and polysome profiling were used to determine the translational effects of FXR1. Immunoprecipitation and immunofluorescence were performed to identify the interaction between FXR1 and cMYC mRNA and eIF4F complex. RNA-immunoprecipitation (RIP), RNA electrophoretic mobility shift assays (REMSA), proximity ligation assays (PLA), and biochemical assays were used to identify the specific site on cMYC mRNA to which FXR1 binds to promote mRNA circularization and translation.ResultsWe found that amplification and copy-gain of FXR1 increased the expression of FXR1 mRNA and FXR1 protein in ovarian cancer patients, and these events associated with poor prognosis. We demonstrated that FXR1 binds to AU-rich elements (ARE) within the 3’ untranslated region (3’UTR) of cMYC. As a consequence, FXR1 binding to cMYC 3’UTR leads to the circularization of mRNA and facilitated the recruitment of eukaryotic translation initiation factors (eIFs) to translation start site for improving protein synthesis.ConclusionWe found that FXR1 upregulates a known oncogene, cMYC, by binding to AU-rich elements within the 3’UTR, leading to the recruitment of the eIF4F complex for cMYC translation. Our findings uncover a novel mechanism of action of FXR1 in tumorigenesis and provides opportunities to use FXR1 and its downstream effectors as biomarkers or therapeutic targets in ovarian and other cancers.

Human coronavirus disease 2019 (COVID-19) is a life-threatening and highly contagious disease caused by coronavirus SARS-CoV-2. Sensitive and specific detection of SARS-CoV-2 virus in tissues and cells of COVID-19 patients will support investigations of the biologic behavior and tissue and cell tropism of this virus. We identified two commercially available affinity-purified polyclonal antibodies raised against Nucleocapsid and Spike proteins of SARS-CoV-2 that provide sensitive and specific detection of the virus by immunohistochemistry in formalin-fixed, paraffin-embedded tissue. Protocols are presented that are mutually validated by matched detection patterns of virus-infected cells in autopsy lung tissue of COVID-19 deceased patients by the two distinctly different antibodies. Negative controls include autopsy lung tissue from patient who died from non-COVID-19 respiratory disease and control rabbit immunoglobulin. SARS-CoV-2 detection in human tissues will provide insights into viral tissue and cell distribution and load in patients with active infection as well as provide insight into clearance of virus in late COVID-19 disease stages.

Purpose: Parathyroid hormone-related protein (PTHrP) is required for normal mammary gland development and biology. A PTHLH gene polymorphism is associated with breast cancer risk, and PTHrP promotes growth of osteolytic breast cancer bone metastases. Accordingly, current dogma holds that PTHrP is upregulated in malignant primary breast tumors, but solid evidence for this assumption is missing. Experimental Design: We used quantitative IHC to measure PTHrP in normal and malignant breast epithelia, and correlated PTHrP levels in primary breast cancer with clinical outcome. Results: PTHrP levels were markedly downregulated in malignant compared with normal breast epithelia. Moreover, low levels of nuclear localized PTHrP in cancer cells correlated with unfavorable clinical outcome in a test and a validation cohort of breast cancer treated at different institutions totaling nearly 800 cases. PTHrP mRNA levels in tumors of a third cohort of 737 patients corroborated this association, also after multivariable adjustment for standard clinicopathologic parameters. Breast cancer PTHrP levels correlated strongly with transcription factors Stat5a/b, which are established markers of favorable prognosis and key mediators of prolactin signaling. Prolactin stimulated PTHrP transcript and protein in breast cancer cell lines in vitro and in vivo, effects mediated by Stat5 through the P2 gene promoter, producing transcript AT6 encoding the PTHrP 1-173 isoform. Low levels of AT6, but not two alternative transcripts, correlated with poor clinical outcome. Conclusions: This study overturns the prevailing view that PTHrP is upregulated in primary breast cancers and identifies a direct prolactin–Stat5–PTHrP axis that is progressively lost in more aggressive tumors.

TPS220 Background: Androgen deprivation therapy (ADT) achieved with gonadotropin releasing hormone (GnRH) agonist or antagonist is considered the standard of care for men with prostate cancer (PC) who develop biochemical recurrence (BCR) after definitive treatment. ADT is associated with significant adverse effects in this asymptomatic population, and hence there is an unmet need for alternate non-hormonal options. Androgen receptor (AR) and its variants (AR-V) are persistently expressed in the majority of the cells in recurrent PCs and drives PC growth. Jak2-Stat5 signaling has been shown to sustain PC cell viability and is critical for PC tumor growth. Stat5 activation in PC at the time of surgery predicts early PC recurrence. Our investigation of the molecular targets downstream of Jak2-Stat5 signaling have revealed the AR gene as a critical target, and the Jak2-Stat5 pathway represents a target to inhibit expression of diverse AR and AR-V species and thereby control of PC growth. Pacritinib (PAC) is a novel JAK2 inhibitor that suppresses wild-type Jak2 in cell-based assays and has demonstrated promising antitumor activity in myelofibrosis. We hypothesize that PAC inhibition of Jak2-Stat5 signaling will induce biochemical responses in men with recurrent PC by depleting AR and AR-V. Methods: BLAST (NCT04635059) is a single arm, open-label, phase 2 study of PAC (200mg BID) for patients with PC who underwent definitive treatment and developed BCR. Eligibility criteria include histologically confirmed PC, BCR with a PSA doubling time ≤ 9 months, PSA > 0.5 ng/mL, and serum testosterone > 150 ng/dL. 46 subjects will be enrolled with a primary objective to assess the effect of PAC on time to PSA progression. The primary endpoint is six-month PSA progression free survival per PCWG3 criteria. The null hypothesis that the median PSA-progression-free survival is six months will be tested against a one-sided alternative for the six-month PSA-progression-free survival probability exceeding 50%. Secondary endpoints include time to subsequent therapy, safety and toxicity. Exploratory endpoints include effect of PAC on geriatric domains. An interim analysis will be performed when 10 patients have been treated and followed for six months. Accrual began in July 2021. Clinical trial information: NCT04635059.

Background: Patients with hormone receptor-positive (HR+) breast cancer (BC) experience significant improvement in long-term outcomes with endocrine therapy (ET). However, metastatic recurrences of endocrine resistant disease develop in about 20-25% of patients and remain a major cause of BC mortality. Up-regulation of HER family growth factor receptor tyrosine kinases (RTKs) represent early escape mechanisms in tumors treated with ET. Neoadjuvant endocrine therapy (NET) offers a unique opportunity to identify responsiveness of HR+ BCs and detect tumors that display up-regulation of HER RTKs. Methods: A single arm, interventional, exploratory clinical trial evaluating four weeks of NET in early stage HR+/HER2-negative BC patients was conducted at our institution (NCT03219476). The primary objective was to assess changes in HER protein expression (HER1-4) from diagnostic core biopsies to surgically resected tumors treated with NET. Secondary objectives included assessment of other molecular markers, tumor proliferation and volumetric responses. Optimized protocols for immunohistochemistry (IHC) were used for HER1-4, and HER2 status was further assessed by fluorescence in situ hybridization (FISH) if IHC (2+) equivocal. Up-regulation was defined as an increase of ≥ 1 in IHC scores (ordinal 0,1,2,3) or gene amplification by FISH. Chi-square tests of independence and one sample difference in proportion tests were performed. Linear regression was used to evaluate association of variables of interest with the primary outcome. A significance level of 0.05 was used throughout. Results: Thirty-seven patients with cT1-T3, cN0 HR+/HER2-negative BC were enrolled. One patient had multifocal disease resulting in 38 tumors. Patient and tumor characteristics are shown in Table 1. There was no significant change in ER-positivity between pre- and post-treatment specimens. However, a trend towards decrease in PR-positivity was seen in post-treatment tumors consistent with functional ER pathway disruption (p=0.08). HER1-4 proteins were significantly up-regulated in 44.7% tumors (17/38) with HER2 being the most frequently up-regulated HER RTK (p=0.035). HER3 and HER4 were down-regulated in 50% tumors (19/38). Three patients converted to HER2-positive status (IHC 3+ or FISH amplified) at surgery and received adjuvant trastuzumab-based treatment. Ki67 decreased in 71% tumors [median 3.35 (range 0.06-25.5)] and increased in 26.3% tumors [median 1 (range 0.08-3.78)]. No significant associations were identified between any clinic-pathologic covariates and change in HER1-4 protein expression on multivariate analysis. Conclusions: HER1-4 proteins were significantly up-regulated in 44.7% of tumors after short-term NET in patients with early stage HR+/HER2-negative BC, with HER2 up-regulation being the most predominant and statistically significant. Down-regulation in HER3 and HER4 were seen in 50% of tumors, however the biological and clinical significance of this finding is unclear. Short-term NET is a promising strategy to identify HR+ tumors that up-regulate HER2 as an early escape pathway and endocrine resistance mechanism. Patients with such HER2 up-regulated tumors after NET may benefit from HER2-directed therapies upon disease recurrence or as adjuvant combination therapy. These findings need to be further explored in larger randomized clinical trials. Table 1.Median Age (range)64yrs (42-81)Median BMI (range)28.3 (19.3-55.1)Post-menopausal, N (%)31 (83.8)Median clinical tumor size (range)1.3cm (0.5-7.7)Invasive ductal, N (%)26 (70)Grade, N (%)Low16 (43.2)Intermediate18 (47.4)High4 (10.5)Median tumor size at surgery (range)1.2cm (0.09-4)pN stage at surgery, N (%)N030 (81)N17 (19)NET, N (%)Aromatase inhibitors28 (75.6)Tamoxifen9 (24.4) Citation Format: Lubna Naaz Chaudhary, Julie M Jorns, Yee Chung Cheng, Sailaja Kamaraju, John Burfeind, Mary Beth Gonyo, Amanda Kong, Caitlin Patten, Tina Yen, Chandler Cortina, Ebony Carson, Nedra Johnson, Carmen Bergom, Anjishnu Banerjee, Yu Wang, Yunguang Sun, Christopher R Chitambar, Hallgeir Rui. HER1-4 protein up-regulation following short-term neoadjuvant endocrine therapy in patients with hormone receptor-positive HER2-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-02-03.

The chaperone protein and guanine nucleotide exchange factor SmgGDS (RAP1GDS1) is a key promoter of cancer cell proliferation and tumorigenesis. SmgGDS undergoes nucleocytoplasmic shuttling, suggesting that it has both cytoplasmic and nuclear functions that promote cancer. Previous studies indicate that SmgGDS binds cytoplasmic small GTPases and promotes their trafficking to the plasma membrane. In contrast, little is known about the functions of SmgGDS in the nucleus, or how these nuclear functions might benefit cancer cells. Here we show unique nuclear localization and regulation of gene transcription pathways by SmgGDS. Strikingly, SmgGDS depletion significantly reduces expression of over 600 gene products that are targets of the DREAM complex, which is a transcription factor complex that regulates expression of proteins controlling the cell cycle. The cell cycle regulators E2F1, MYC, MYBL2 (B-Myb) and FOXM1 are among the DREAM targets that are diminished by SmgGDS depletion. E2F1 is well known to promote G1 cell cycle progression, and the loss of E2F1 in SmgGDS-depleted cells provides an explanation for previous reports that SmgGDS depletion characteristically causes a G1 cell cycle arrest. We show that SmgGDS localizes in nucleoli, and that RNAi-mediated depletion of SmgGDS in cancer cells disrupts nucleolar morphology, signifying nucleolar stress. We show that nucleolar SmgGDS interacts with the RNA polymerase I transcription factor upstream binding factor (UBF). The RNAi-mediated depletion of UBF diminishes nucleolar localization of SmgGDS and promotes proteasome-mediated degradation of SmgGDS, indicating that nucleolar sequestration of SmgGDS by UBF stabilizes SmgGDS protein. The ability of SmgGDS to interact with UBF and localize in the nucleolus is diminished by expressing DiRas1 or DiRas2, which are small GTPases that bind SmgGDS and act as tumor suppressors. Taken together, our results support a novel nuclear role for SmgGDS in protecting malignant cells from nucleolar stress, thus promoting cell cycle progression and tumorigenesis.

Insulin-like growth factor binding protein 3 (IGFBP3) modulates cell growth through IGF-dependent and -independent mechanisms. Reports suggest that the serum levels of IGFBP3 are associated with various cancers and that IGFBP3 expression is significantly decreased in cisplatin (CDDP)-resistant lung cancer cells. Based on these findings, we investigated whether Igfbp3 deficiency accelerates mouse lung tumorigenesis and if expression of IGFBP3 enhances CDDP response by focusing on the IGF1 signaling cascade. To this end, an Igfbp3-null mouse model was generated in combination with KrasG12D to compare the tumor burden. Then, IGF-dependent signaling was assessed after expressing wild-type or a mutant IGFBP3 without IGF binding capacity in non–small cell lung cancer (NSCLC) cells. Finally, the treatment response to CDDP chemotherapy was evaluated under conditions of IGFBP3 overexpression. Igfbp3-null mice had increased lung tumor burden (>2-fold) and only half of human lung cancer cells survived after expression of IGFBP3, which corresponded to increased cleaved caspase-3 (10-fold), inactivation of IGF1 and MAPK signaling. In addition, overexpression of IGFBP3 increased susceptibility to CDDP treatment in lung cancer cells. These results, for the first time, demonstrate that IGFBP3 mediates lung cancer progression in a KrasG12D mouse model. Furthermore, overexpression of IGFBP3 induced apoptosis and enhanced cisplatin response in vitro and confirmed that the suppression is in part by blocking IGF1 signaling. Implications: These findings reveal that IGFBP3 is effective in lung cancer cells with high IGF1 signaling activity and imply that relevant biomarkers are essential in selecting lung cancer patients for IGF1-targeted therapy. Mol Cancer Res; 15(7); 896–904. ©2017 AACR.

OBJECTIVES: Assess the pathologic changes in the lungs of COVID-19 decedents and correlate these changes with demographic data, clinical course, therapies, and duration of illness. METHODS: Lungs of 12 consecutive COVID-19 decedents consented for autopsy were evaluated for gross and histopathologic abnormalities. A complete Ghon "en block" dissection was performed on all cases; lung weights and gross characteristics recorded. Immunohistochemical studies were performed to characterize lymphocytic infiltrates and to assess SARS-CoV-2 capsid protein. RESULTS: Two distinct patterns of pulmonary involvement were identified. Three of 12 cases demonstrated a predominance of acute alveolar damage (DAD) while 9 of 12 cases demonstrated a marked increase in intra-alveolar macrophages in a fashion resembling desquamative interstitial pneumonia or macrophage activation syndrome (DIP/MAS). Two patterns were correlated solely with a statistically significant difference in the duration of illness. The group exhibiting DAD had duration of illness of 5.7 days while the group with DIP/MAS had duration of illness of 21.5 days (t-test p = 0.014). CONCLUSIONS: The pulmonary pathology of COVID-19 patients demonstrates a biphasic pattern, an acute phase demonstrating DAD changes while the patients with a more prolonged course exhibit a different pattern that resembles DIP/MAS-like pattern. The potential mechanisms and clinical significance are discussed.

As of October 2020, there are over 40 million confirmed cases, and more than 1 million confirmed deaths of Covid-19 worldwide. The main cause of death in hospitalized patients is a respiratory failure due to acute respiratory distress syndrome. It has been suggested that the very intense immune response induces diffuse alveolar damage that far exceeds the harm that would have been caused by virus replication per se, resulting in lethal tissue destruction. We present a detailed report of the histopathological findings on cryo transbronchial biopsy in the patient with persistent (3 months) interstitial pneumonitis and severe CD8 positive cell infiltration in the lungs due to SARS-CoV-2 infection. CD8 positive T-lymphocytes have a great potential to damage tissue either through direct cytotoxicity or through cytokines release.

Epithelial-mesenchymal transition (EMT) is a critical event in metastasis of colorectal cancer (CRC). Rho/ROCKs signaling has a pivotal role in orchestrating actin cytoskeleton, leading to EMT and cancer invasion. However, the underlying mechanisms for ROCKs activation are not fully understood. Here, we identified FOXM1D, a novel isoform of Forkhead box M1 (FOXM1) that has a pivotal role in ROCKs activation by directly interacting with coiled-coil region of ROCK2. FOXM1D overexpression significantly polymerizes actin assembly and impairs E-cadherin expression, resulting in EMT and metastasis in xenograft mouse model and knockdown of FOXM1D has the opposite effect. Moreover, a high FOXM1D level correlates closely with clinical CRC metastasis. FOXM1D-induced ROCKs activation could be abrogated by the ROCKs inhibitors Y-27632 and fasudil. These observations indicate that the FOXM1D-ROCK2 interaction is crucial for Rho/ROCKs signaling and provide novel insight into actin cytoskeleton regulation and therapeutic potential for CRC metastasis.