Biology subjects

Orsulic, S.

Publications and source records attributed to Orsulic, S..

5 recordsLinked to original sources

bioRxiv2026

Spatially resolved transcriptional programs link fallopian tube precursor lesions to immune activation and stromal reorganization

Despite its name, high-grade serous ovarian carcinoma (HGSC) originates in the fallopian tube, not the ovary, arising from a morphologically recognizable precursor lesion, serous tubal intraepithelial carcinoma (STIC). Yet the early cellular and microenvironmental changes driving this transformation remain poorly understood, limiting progress in early detection, interception, and prevention. Here, we generated a Visium HD spatial transcriptomic atlas of fallopian tube carcinogenesis spanning histologically unremarkable fallopian tube epithelium (FTE), STIC, and invasive HGSC. This approach enabled unbiased, tissue-wide, whole-transcriptome mapping at single-cell-level resolution within preserved histologic architecture, providing spatial granularity beyond prior region-of-interest-based platforms. STIC lesions displayed a coordinated epithelial transformation program marked by proliferation, replication stress, DNA repair activation, chromatin remodeling, and induction of tumor-associated antigens, including PRAME and CLDN6, which are emerging targets for vaccine and antigen-directed therapeutic strategies. In contrast, histologically unremarkable FTE contained spatially restricted epithelial defense programs marked by SCGB1A1 and MUC6, suggesting localized protective states that may influence susceptibility to malignant transformation. Using distance- and density-aware spatial analyses, we found that precursor lesions were embedded within immune-enriched, stromal-depleted microenvironments characterized by interferon-dominant immune activation, attenuation of TNF/NF-{kappa}B signaling, macrophage and lymphoid remodeling, and extracellular matrix-associated fibroblast interactions. Computational pathology analysis of collagen architecture confirmed reduced collagen fiber density in STIC-adjacent stroma, linking transcriptomic evidence of stromal remodeling to structural extracellular matrix changes. Together, these data define early epithelial, immune, and stromal programs associated with STIC and identify tumor-associated antigens, epithelial defense states, and immune-stromal niches as candidate targets for HGSC prevention and early interception.

cancer biology↗

bioRxiv2026

Deformability screening identifies NUDT5 as a mediator of cellular mechanobiology

How cells deform, sense, and respond to mechanical cues drives physiological and disease processes ranging from development to cancer metastasis; however, unbiased approaches to identify mechanical mediators are lacking. We screened 1280 compounds to identify modulators of cancer cell deformability using a cellular filtration assay and identified 92 compounds that significantly reduced deformability of ovarian cancer cells; top hits also reduced migration and invasion. Connectivity mapping of the top 21 compounds identified NUDT5 (Nudix hydrolase 5) as a predicted mechanical mediator; transcriptomic analyses implicated NUDT5 in mechanobiology and metabolic processes. We confirmed that NUDT5 mediates intracellular ATP and cellular mechanical behaviors, including morphology and deformability. In ovarian cancer, increased NUDT5 levels were associated with higher tumor stage and worse patient survival; NUDT5 inhibition reduced migration and colony formation in vitro and peritoneal tumor burden in mice. These findings establish deformability-based screening as a platform for discovering mechanical mediators and identify NUDT5 as a therapeutic target in ovarian cancer. TeaserScreening cells based on deformability provides an unbiased approach to identify NUDT5 as a mediator of cell mechanics

cell biology↗

bioRxiv2025

Combined inhibition of NAD synthesis and C-terminal binding protein cooperatively induce cell death and inhibit growth of High Grade Serous Ovarian Carcinoma

The transcriptional scaffolds C-terminal Binding Proteins (CtBP) 1 and 2 are overexpressed and act as oncogenic dependencies in multiple cancers but importantly encode a chemically targetable dehydrogenase domain. CtBP promotes survival of high grade serous ovarian carcinoma (HGSOC) cells by repressing expression of Death Receptors (DR) 4 and 5, which activate caspase 8-dependent apoptosis. We have previously developed a series of substrate competitive CtBP dehydrogenase inhibitors active in multiple cell and preclinical solid tumor models. In the current study, we validated CtBP 1 and 2 overexpression in a longitudinal series of primary and metastatic/recurrent HGSOC cases. Furthermore, our lead CtBP dehydrogenase inhibitor, JW-98 induced apoptosis and exhibited variable single agent IC50 values in HGSOC cell lines, but depletion of nicotinamide adenine dinucleotide (NAD) using the NAD synthesis inhibitor GMX1778 strikingly sensitized tumor cells to JW-98 treatment. Mechanistically, the JW-98/GMX-1778 combination effectively disrupted CtBP dimerization that requires stoichiometric levels of intracellular NAD and is required for oncogenic transcriptional activities. Highlighting the translational potential of this combination, combined JW-98/GMX1778 treatment of OVCAR3 HGSOC xenografts in immunodeficient mice abrogated tumor growth without observable toxicity. CtBP/NAD combined inhibition represents a novel therapeutic strategy that could improve outcomes in chemoresistant HGSOC.

cancer biology↗

bioRxiv2024

Replication stress marker phospho-RPA2 predicts response to platinum and PARP inhibitors in homologous recombination-proficient ovarian cancer

BackgroundOvarian cancer treatment includes cytoreductive surgery, platinum-based chemotherapy, and often poly (ADP-ribose) polymerase (PARP) inhibitors. Homologous recombination (HR)-deficiency is a well-established predictor of therapy sensitivity. However, over 50% of HR-proficient tumors also exhibit sensitivity to standard-of-care treatments. Currently, there are no biomarkers to identify which HR-proficient tumors will be sensitive to standard-of-care therapy. Replication stress may serve as a key determinant of response. MethodsWe evaluated phospho-RPA2-T21 (pRPA2) foci via immunofluorescence as a potential biomarker of replication stress in formalin-fixed, paraffin-embedded tumor samples collected at diagnosis from patients treated with platinum chemotherapy (discovery cohort: n = 31, validation cohort: n = 244) or PARP inhibitors (n = 87). Recurrent tumors (n = 37) were also analyzed. pRPA2 scores were calculated using automated imaging analysis. Samples were defined as pRPA2-High if > 16% of cells had [≥] 2 pRPA2 foci. ResultsIn the discovery cohort, HR-proficient, pRPA2-High tumors demonstrated significantly higher rates of pathologic complete response to platinum chemotherapy than HR-proficient, pRPA2-Low tumors. In the validation cohort, patients with HR-proficient, pRPA2-High tumors had significantly longer survival after platinum treatment than those with HR-proficient, pRPA2-Low tumors. Additionally, the pRPA2 assay effectively predicted survival outcomes in patients treated with PARP inhibitors and in recurrent tumor samples. ConclusionOur study underscores the importance of considering replication stress markers alongside HR status in therapeutic planning. Our work suggest that this assay could be used throughout a patients treatment course to expand the number of patients receiving effective therapy while reducing unnecessary toxicity.

cancer biology↗

bioRxiv2024

Ablation of hematopoietic stem cell derived adipocytes reduces tumor burden in syngeneic mouse models of high-grade serous carcinoma

Hematopoietic stem cell-derived adipocytes (HSCDAs) are an adipose subtype derived from myeloid precursors that are distinct from conventional mesenchymal adipocytes (CMAs). We hypothesized that HSCDAs promote high grade serous carcinoma (HGSC), the most common form of ovarian cancer. Despite similar rates of differentiation, primary human HSCDAs from female donors showed marked transcriptional differences from CMAs, including downregulation of cell cycle and upregulation of lipid metabolic pathways. HSCDAs secreted greater amounts of inflammatory cytokines than CMAs. We also conducted two independent tumor studies using ID8 and SO syngeneic HGSC murine models in immunocompetent mice that were either HSCDA Proficient (HSCDA-Pro; can make both adipocyte subtypes) or Deficient (HSCDA-Def; can only make CMAs). Tumor burden trended lower in HSCDA-Def mice in both models. Relative to HSCDA-Pro mice, omental ID8 tumors from HSCDA-Def mice downregulated transcription of multiple metabolic pathways that were enriched in human HSCDA cells in vitro, suggesting that ablation of HSCDAs altered the tumor metabolic environment. Compared to HSCDA-Pro mice, tumors from HSCDA-Def mice had lower densities of dendritic cells (DC) and natural killer (NK) cells, as well as fewer DCs, NKs, and B-cells in proximity to tumor cells. Our data suggest that HSCDAs alter the peritoneal immune and metabolic environment to support HGSC progression. ONE SENTENCE SUMMARYHematopoietic stem cell derived adipocytes may alter the peritoneal metabolic and immune environment to establish a metastatic niche and support ovarian cancer progression.

cancer biology↗