Arun Kanakkanthara

Global incidence and mortality rates for endometrial and cervical cancers have been steadily rising, while these rates for ovarian cancer have decreased. Although these cancers represent unique diseases and challenges, overlapping biology and responses to targeted therapies and immunotherapies create opportunities to advance research through shared knowledge and resources. In 2025, investigators funded by US National Cancer Institute (NCI) Specialized Programs of Research Excellence (SPORE) and other NCI-supported grants convened a hybrid meeting to identify challenges and knowledge gaps in translational research, highlight advances, define shareable resources and technologies, and foster collaboration among the Gynecologic Cancer SPORE sites, patient advocates, and NCI staff. Special sessions were arranged for presentations by patient advocates, early-stage investigators, and investigators transitioning to gynecologic cancer research. Meeting-wide workshops on sharing resources and reducing time to activation of clinical trials as well as networking events were included. Collectively, the presentations converged on 3 overarching themes: (1) interception and early-disease biology, (2) development of innovative targeted and immune-based therapies, and (3) the critical role of shared resources and collaborative infrastructure in accelerating translational progress. The unifying theme across disease sites was molecular advances to improve early detection and prevention and to drive therapeutic advancements. Novel findings discussed included candidate precursor cells and mechanisms of high-grade serous ovarian cancer development, therapeutic vaccines and their delivery methods for cervical dysplasia, identification of immune-targetable ovarian cancer antigens, various novel molecularly targeted drugs and immune-based agents for endometrial and ovarian cancers, and approaches to bypass drug resistance. Workshops delineated actionable strategies to further advance gynecologic cancer translational research.

RAD51 is a central protein in the homologous recombination (HR) pathway and is essential for the accurate repair of DNA double-strand breaks (DSBs). Following DSB formation, DNA end resection generates single-stranded DNA substrates that facilitate the recruitment and assembly of RAD51 nucleoprotein filaments at sites of damage. This process results in the formation of discrete nuclear RAD51 foci, which serve as a widely accepted functional readout of HR activity and a surrogate marker of HR proficiency. Because defects in HR are common in several malignancies, particularly ovarian and breast cancers, assessment of RAD51 foci formation has emerged as an important approach for evaluating DNA repair capacity and predicting response to DNA-damaging therapies, including platinum compounds and poly(ADP-ribose) polymerase (PARP) inhibitors, whose efficacy is strongly influenced by HR repair status. This manuscript describes a simple, reliable, and reproducible immunofluorescence-based protocol for the detection and quantification of RAD51 nuclear foci in cultured ovarian cancer cells. The method involves induction of DNA damage by ionizing radiation (IR), followed by fixation, immunostaining with antibodies against RAD51 and γH2AX, confocal microscopy, and manual quantitative analysis of RAD51/γH2AX co-localized foci. The protocol can be applied under basal conditions or after genetic and pharmacological perturbations to determine their effects on HR function. Representative results demonstrate robust induction of RAD51 foci in HR-proficient ovarian cancer cells following DNA damage, whereas RAD51 depletion markedly reduces foci formation despite comparable levels of DSBs, confirming assay specificity. Overall, this protocol provides a robust and reproducible functional assay for assessing HR competency, with broad applications in preclinical and potentially translational cancer research.

Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) are an important therapy for high-grade serous ovarian cancer (HGSOC). However, PARPi resistance frequently emerges, necessitating previously unrecognized approaches to improve HGSOC responses. Here, we showed that the anaplastic lymphoma kinase (ALK) inhibitor brigatinib enhances PARPi activity in HGSOC cells by disrupting an adaptive survival mechanism orchestrated by Fos-related antigen 1 (FRA1) in response to PARPi. This effect of brigatinib occurred through an ALK-independent pathway, wherein brigatinib induced a dual blockade of focal adhesion kinase (FAK) and EPH receptor A2 (EPHA2) tyrosine kinases, leading to the suppression of protein kinase B (Akt) and extracellular-regulated kinase (ERK) signaling accompanied by disruption of a phosphorylation event crucial for FRA1 protein stability. Moreover, in HGSOC patient-derived xenograft (PDX) models, brigatinib and PARPi combination therapy induced tumor regression and improved overall survival compared with PARPi alone, particularly in models with high FAK and EPHA2. These findings support dual targeting of FAK and EPHA2 as a strategy to achieve effective and durable PARPi responses and identify a promising biomarker-based combinatorial approach using brigatinib and PARPi for HGSOC, particularly the subset characterized by high FAK and EPHA2.

Supplementary Materials and Methods

Supplementary Table S2. PDX models minimal information standard (PDX-MI).

Supplementary Table S3. P-values for indicated PDX tumor growth comparisons

Supplementary Figures 1-8 with legends

Supplementary Table 1 showing qRT-PCR primer sequences