Citations

This cohort study evaluates the reduction in risk of high-grade serous carcinoma among women undergoing opportunistic bilateral salpingectomy in Canada.

Abstract DAB2IP (Disabled homolog 2 interacting protein), a recognized tumor suppressor, plays a pivotal role in regulating various oncogenic pathways. Our previous research demonstrated that DAB2IP functions as a cell cycle regulator by facilitating PLK1-mediated mitosis progression. Here, we elucidate a novel function of DAB2IP in promoting DNA replication origin firing. Mechanistically, we identified that DAB2IP localizes to the nucleus, where it interacts with the histone acetyltransferase HBO1 and enhances the HBO1–PLK1 interaction. DAB2IP facilitates PLK1-mediated phosphorylation of HBO1, which subsequently promotes HBO1-directed acetylation of histone 3 at lysine 14 (H3K14Ac). This modification enables the loading of the minichromosome maintenance protein (MCM) complex onto chromatin, thereby supporting DNA replication and maintaining genome integrity. Additionally, we found that ATR regulates CDK1-mediated phosphorylation of DAB2IP, and that this phosphorylation is essential for the formation and activation of the HBO1-PLK1 complex. Ablation of DAB2IP phosphorylation results in increased genomic instability due to incomplete replication of genomic DNA, as evidenced by the accumulation of anaphase ultrafine bridges and 53BP1 nuclear bodies in G1 phase of the cell cycle. In summary, our findings underscore the critical regulatory role of DAB2IP in DNA replication initiation and genomic stability maintenance, providing new insights into its function in cellular homeostasis.

Abstract The tumor landscape of pancreatic ductal adenocarcinoma (PDAC) is refractory to conventional photon radiotherapy (RT) because of a fibrotic tumor microenvironment (TME) that promotes chronic hypoxia and reduced immune surveillance. The radiobiological factors unique to carbon ion RT (CIRT), such as high linear energy transfer and less dependence on oxygen, make it well-suited to overcome the PDAC TME. In this study, we utilized clonal syngeneic KPC pancreatic tumor cell lines and tumors to examine this postulate and to identify underlying factors that affect the response of PDAC to CIRT. Although KPC cell lines exhibited radiobiological effectiveness greater than 3, subcutaneous tumors in the mouse hind leg showed lower radiobiological effectiveness—1.3 based on quintupling time—at a linear energy transfer between 70 and 80 keV/μm. Four days after CIRT, we observed widespread transcriptomic changes in the tumor immune microenvironment, suggesting increased infiltration of antitumor immune cells and elevated expression of antitumor T-cell cytokines, MHC class I molecules, and co-stimulatory signals. Fewer immunologic changes were observed following photon irradiation. By 7 days after CIRT, tumor-supportive transcriptomic programs characterized by protumor cytokines, M2 macrophages, and cancer-associated fibroblasts emerged, promoting resistance and limiting the durability of tumor growth delay. These findings suggest that CIRT may offer a favorable platform compared with conventional photon RT for combining with immunotherapies. Furthermore, these data highlight the risk of using in vitro survival data alone in treatment planning and indicate that underlying TME factors affect the response of PDAC in vivo.

Abstract Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare, deadly form of ovarian cancer that uniformly harbors mutations in SMARCA4, a member of the SWI/SNF chromatin remodeling complex. SWI/SNF impacts RNA splicing, and dysregulation of splicing can generate immunogenic tumor antigens. Here, we explored the relationship between SMARCA4 loss and RNA splicing dysregulation. SCCOHT primary tumors harbored tumor-associated outlier splicing events compared to normal tissues. Many of the tumor events were retained introns encoding novel peptides predicted to bind to MHC-I complexes. Immune cells were observed in primary SCCOHT tumors, suggesting a potentially immune reactive tumor microenvironment. Mutations in several SWI/SNF subunits were associated with higher rates of outlier retained introns across tumor types in TCGA data. Interestingly, RNA sequencing of isogenic SCCOHT cell lines demonstrated a role for SMARCA4 in intron retention. Distinct protein-protein interactions between splicing factors identified in SCCOHT cell lines supported a role for SMARCA4 in splicing regulation. Further, SWI/SNF localized to genes which were differentially spliced. Mass spectrometry analyses confirmed expression of some of these novel peptides and a subset of these are predicted to bind to MHC-I complexes. A pool of these novel peptides derived from retained introns in SCCOHT triggered proliferation and expression of TNFa and INFb in primary human T cells. Together, these data suggest that SMARCA4 loss in SCCOHT leads to intron retention. Furthermore, T cell activation by novel peptides encoded by these tumor-specific splicing events suggests intron retention could be a source of tumor-associated antigens in SCCOHT. Citation Format: Elizabeth Raupach, Apurva Hegde, Krystine Garcia-Masnfield, Marice Alcantara, David Rose, Rebecca Halperin, Krystal Orlando, Jessica Lang, Ritin Sharma, Victoria David-Dirgo, Salvatore Facista, Rayvon Moore, Rochelle Kofman, Zoe Jensen, Victoria Zismann, Anthony Karnezis, Yemin Wang, Lynda Bennett, Timothy Whitsett, Marcin Kortylewski, William Hendricks, David Huntsman, Lorna Rodriguez-Rodriguez, Bernard Weissman, Jeffrey Trent, Patrick Pirrotte. Loss of SMARCA4 leads to intron retention and generation of tumor-associated antigens in small cell carcinoma of the ovary, hypercalcemic type [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Ovarian Cancer Research; 2025 Sep 19-21; Denver, CO. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl):Abstract nr B065.

Abstract Introduction: The purpose of this study is to evaluate the effectiveness of opportunistic salpingectomy (OS), a procedure that aims to remove only the fallopian tubes of general population risk women, for the prevention of epithelial ovarian cancer. Currently, the method of prevention for individuals at high risk of ovarian cancer involves a bilateral salpingo-oophorectomy (BSO), a procedure that removes both the fallopian tubes and ovaries. However, this procedure is not recommended for individuals of the general population, who make up about 80% of ovarian cancers, due to negative health implications to the cardiovascular and skeletal systems because of surgically induced menopause. The effectiveness of the OS in preventing ovarian cancers and how the procedure impacts the histotype distribution of ovarian cancers remains unknown. Study Methods: This study uses a population-based approach and a case-based approach to determine the effectiveness of OS and its impact on histotype distribution, respectively. For the population-based analysis, we will search through clinical databases to acquire cases of individuals who have had an OS and a tumor. A control population who have their fallopian tubes in-tact will also be acquired. A cox-proportional hazard analysis will be performed to determine the effectiveness of the procedure. Using pathological records, the case-based ascertainment of tumors from individuals who have had an OS will be selected and reviewed for histotype confirmation. Fallopian tubes of these patients will also be reviewed for precursor lesions. This cohort will be compared to a historical histotype distribution of ovarian cancers. Results: For the population-based approach, we have to date, identified less than five serous ovarian cancers in individuals who have had an OS (n=40, 477). A comparator surgery was used as a control and showed 21 cancers. For the case-based approach, we have partnered with 23 collaborating institutions from around the world to identify tumors in individuals who have had an OS. We have identified 26 epithelial ovarian cancers, with the most lethal gynecological histotype, high grade serous carcinoma (HGSC), accounting for 23.1% of the total proportion of epithelial ovarian cancer cases (n=6/26). This is significantly less than the historical histotype distribution of HGSC, which is 69.3% (Fisher’s exact test, p<0.0001). One HGSC case had a precursor lesion called a serous tubal intraepithelial carcinoma (STIC) while reviewing fallopian tubes of this individual. TP53 mutation analysis on one HGSC tumor sample showed a frameshift mutation in TP53 (c229fs) with the tumor and the corresponding STIC staining negative for p53 protein expression by immunohistochemistry. Conclusion: This evidence demonstrates the effectiveness of opportunistic salpingectomy for the prevention of ovarian cancer and shows a histotype distribution shift, with the most lethal gynecological malignancy having a significant reduction in cases following the procedure. Citation Format: Ramlogan Sowamber, Alice J. Mei, Paramdeep Kaur, Julianne McLeod, Emily McKay, Alex Lukey, Jamie Bakkum-Gamez, Natalia Buza, Paul Cohen, Kyle Devins, Rhonda Farrell, Christine Garcia, Blake Gilks, Ellen Goode, Anjelica Hodgson, Brooke Howitt, Pei Hui, Jutta Huvila, Anthony Karnezis, Kianoosh Keyhanian, Mary Kinloch, Martin Köbel, Felix KF. Kommoss, Lawrence Kushi, Janice S. Kwon, Kara Long-Roche, Anais Malpica, Jessica N. McAlpine, Dianne Miller, Esther Oliva, Andrea Palicelli, Aleksandra Paliga, Carlos Parra-Herran, Celeste Leigh Pearce, Sharnel Perera, Jurgen M. Piek, Haiyan Qiu, Joseph Rabban, Robert Rome, Miranda Steenbeek, Rebecca Stone, Aline Talhouk, Kristin M. Tischer, Britton Trabert, Penelope M. Webb, John R. Zalcberg, Gillian E. Hanley, David G. Huntsman. Evaluating the effectiveness of opportunistic salpingectomy (OS) for the prevention of epithelial ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Ovarian Cancer Research; 2025 Sep 19-21; Denver, CO. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl):Abstract nr B045.

Abstract The tumor landscape of pancreatic ductal adenocarcinoma (PDAC) is refractory to conventional photon radiotherapy (RT) due to a fibrotic tumor microenvironment (TME) that promotes chronic hypoxia and reduced immune surveillance. The radiobiological factors unique to carbon ion radiotherapy (CIRT), such as high linear energy transfer (LET) and less dependence on oxygen, make it well-suited to overcome the PDAC TME. Here, we utilized clonal syngeneic KPC pancreatic tumor cell lines and tumors to examine this postulate and to identify underlying factors that impact the response of PDAC to CIRT. While KPC cell lines exhibited radiobiologic effectiveness (RBE) greater than 3, subcutaneous tumors in the mouse hind leg showed lower RBEs – 1.3 based on quintupling time – at a LET of 75 keV/μm. Four days after CIRT, we observed widespread transcriptomic changes in the tumor immune microenvironment (TME), suggesting increased infiltration of anti-tumor immune cells, elevated expression of anti-tumor T cell cytokines, MHC class I molecules, and co-stimulatory signals. Fewer immunologic changes were observed following photon irradiation. By seven days after CIRT, tumor-supportive transcriptomic programs characterized by pro-tumor cytokines, M2 macrophages, and cancer-associated fibroblasts (CAFs) emerged, promoting resistance and limiting the durability of tumor growth delay. These findings suggest that CIRT may offer a favorable platform compared to conventional photon radiation therapy for combining with immunotherapies. Furthermore, these data highlight the risk of using in vitro survival data alone in treatment planning and indicate that underlying TME factors impact the response of PDAC in vivo .

ABSTRACT Hypoxic stress responses are essential for cellular and organismal survival and drive gene regulation across diverse biological pathways, including cell cycle progression and energy metabolism. Here, we show that topoisomerase IIβ (TOP2B) regulates DNA topology and transcription of hypoxia-inducible genes (HIGs) in a DNA-dependent protein kinase (DNA-PK)-dependent manner. Integrated cellular, biochemical, and genomic analyses reveal an antagonistic yet correlated relationship between TOP2B and DNA-PK activities. Under normoxic conditions, TOP2B associates with HIGs and represses transcription by suppressing DNA negative supercoiling formation and accessibility. Under hypoxic exposure, TOP2B dissociates from HIGs, while DNA-PK and HIF1α are recruited to activate HIGs. Notably, DNA-PK is required for the repressive function of TOP2B, as DNA-PK knockout abrogates TOP2B release and activity, resulting in elevated expression of a number of HIGs. Mechanistically, DNA-PK phosphorylates TOP2B at T1403, stimulating its catalytic activity to restrain DNA unwinding and accessibility, thereby suppressing HIG transcription. Collectively, these findings identify a novel role for TOP2B and DNA-PK-mediated regulation of TOP2B as key transcriptional regulators of HIG expression. We propose that phosphorylation-dependent modulation of TOP2B activity is coordinated with transcriptional states and determines DNA topology to regulate Pol II transcription.

BACKGROUND Despite an overall poor prognosis, about 15% of patients with advanced-stage tubo-ovarian high-grade serous carcinoma (HGSC) survive 10 or more years after standard treatment. METHODS We evaluated the tumor microenvironment of this exceptional, understudied group using a large international cohort enriched for long-term survivors (LTS; 10+ years; n = 374) compared with mid-term (MTS; 5–7.99 years; n = 433) and short-term survivors (STS; 2–4.99 years; n = 416). Primary tumor samples were immunostained and scored for intraepithelial and intrastromal densities of 10 immune-cell subsets (including T cells, B cells, plasma cells, myeloid cells, PD-1 + cells, and PD-L1 + cells) and epithelial content. RESULTS Positive associations with LTS compared with STS were seen for 9 of 10 immune-cell subsets. In particular, the combination of intraepithelial CD8 + T cells and intrastromal B cells showed near 5-fold increased odds of LTS compared with STS. All of these associations were stronger in tumors with high epithelial content and/or the C4/Differentiated molecular subtype, despite immune-cell densities generally being higher in tumors with low epithelial content and/or the C2/Immunoreactive molecular subtype. CONCLUSION The tumor microenvironment of HGSC LTS is distinguished by the intersection of T and B cell coinfiltration, high epithelial content, and C4/differentiated molecular subtype, features which may inspire new approaches to immunotherapy. FUNDING Ovarian Cancer Research Program (OCRP) of the Congressionally Directed Medical Research Program (CDMRP), U.S. Department of Defense (DOD); American Cancer Society; BC Cancer Foundation; Canada’s Networks of Centres of Excellence; Canadian Cancer Society; Canadian Institutes of Health Research; Cancer Councils of New South Wales, Victoria, Queensland, South Australia, and Tasmania, Cancer Foundation of Western Australia; Cancer Institute NSW; Cancer Research UK; Deutsche Forschungsgesellschaft; ELAN Funds of the University of Erlangen-Nuremberg; Fred C. and Katherine B. Andersen Foundation; Genome BC; German Cancer Research Center; German Federal Ministry of Education and Research, Programme of Clinical Biomedical Research; Instituto de Salud Carlos III; Mayo Foundation; Minnesota Ovarian Cancer Alliance; Ministerio de Economía y Competitividad; Medical Research Council (MRC); National Center for Advancing Translational Sciences; National Health and Medical Research Council of Australia (NHMRC); Ovarian Cancer Australia; Peter MacCallum Foundation; Sydney West Translational Cancer Research Centre; Terry Fox Research Institute; The Eve Appeal (The Oak Foundation); UK National Institute for Health Research Biomedical Research Centres at the University of Cambridge; University of Pittsburgh School of Medicine; U.S. National Cancer Institute of the National Institutes of Health; VGH & UBC Hospital Foundation; Victorian Cancer Agency.

ABSTRACT In the United States (US), biosafety and biosecurity oversight of research on viruses is being reappraised. Safety in virology research is paramount and oversight frameworks should be reviewed periodically. Changes should be made with care, however, to avoid impeding science that is essential for rapidly reducing and responding to pandemic threats as well as addressing more common challenges caused by infectious diseases. Decades of research uniquely positioned the US to be able to respond to the COVID-19 crisis with astounding speed, delivering life-saving vaccines within a year of identifying the virus. We should embolden and empower this strength, which is a vital part of protecting the health, economy, and security of US citizens. Herein, we offer our perspectives on priorities for revised rules governing virology research in the US.

Abstract Purpose: Endometrioid ovarian carcinoma (ENOC) is the second most-common type of ovarian carcinoma, comprising 10%–20% of cases. Recently, the study of ENOC has benefitted from comparisons to endometrial carcinomas including defining ENOC with four prognostic molecular subtypes. Each subtype suggests differential mechanisms of progression, although tumor-initiating events remain elusive. There is evidence that the ovarian microenvironment may be critical to early lesion establishment and progression. However, while immune infiltrates have been well studied in high-grade serous ovarian carcinoma, studies in ENOC are limited. Experimental Design: We report on 210 ENOC, with clinical follow-up and molecular subtype annotation. Using multiplex IHC and immunofluorescence, we examine the prevalence of T-cell lineage, B-cell lineage, macrophages, and populations with programmed cell death protein 1 or programmed death-ligand 1 across subtypes of ENOC. Results: Immune cell infiltrates in tumor epithelium and stroma showed higher densities in ENOC subtypes with known high mutation burden (POLEmut and MMRd). While molecular subtypes were prognostically significant, immune infiltrates were not (overall survival P > 0.2). Analysis by molecular subtype revealed that immune cell density was prognostically significant in only the no specific molecular profile (NSMP) subtype, where immune infiltrates lacking B cells (TILB minus) had inferior outcome (disease-specific survival: HR, 4.0; 95% confidence interval, 1.1–14.7; P < 0.05). Similar to endometrial carcinomas, molecular subtype stratification was generally superior to immune response in predicting outcomes. Conclusions: Subtype stratification is critical for better understanding of ENOC, in particular the distribution and prognostic significance of immune cell infiltrates. The role of B cells in the immune response within NSMP tumors warrants further study.