Metabolic and Mechanical Regulation of Intercellular Competition in the Peritoneal Metastatic Niche of Ovarian Cancer

Abstract

Ovarian cancer remains the most lethal gynecological malignancy, with mortality primarily attributable to widespread peritoneal metastasis. This transcoelomic dissemination involves exfoliated cancer cells colonizing peritoneal surfaces by breaching the mesothelial barrier—a protective monolayer that constitutes the first line of defense against cancer. However, the mechanisms by which the peritoneal tumor microenvironment facilitates this colonization remain incompletely understood. This doctoral thesis establishes intercellular competition as a unifying framework for understanding peritoneal metastasis, demonstrating that biochemical stress, mechanical forces, and redox gradients dynamically modulate the competitive outcomes between cancer and mesothelial cells. To begin with, through the first study, I revealed that the dicarbonyl metabolite methylglyoxal (MG), which accumulates in diabetes and aging, fundamentally alters competitive fitness by selectively debilitating mesothelial cells while sparing cancer cells. Exposure to MG induced protein glycation, forming advanced glycation end products (AGEs) that disrupted mesothelial cytoskeletal organization (F-actin decorticalization, ezrin, and ZO-1 mislocalization), impaired migration, and decreased viability. Critically, I demonstrated that ovarian cancer cells can escape these effects by elevating glyoxalase-1 (GLO-1) expression, which detoxifies MG to lactate. Analysis of clinical proteomic data confirmed that higher GLO-1 expression in ovarian tumors correlated with poor survival. Interestingly. Pharmacological inhibition of GLO-1 restored cancer cell susceptibility to MG, thereby identifying a precision therapeutic strategy for patients with metabolically stressed tumors. Thereafter, through the second study, I established that mechanical distension caused by ascites-induced elevated intraperitoneal pressure can independently promote cancer colonization. By developing and subsequently deploying a novel microfluidic organ-on-a-chip platform that incorporates gravity-driven perfusion and hydraulic-mediated distension (utilizing a ~200 μm PDMS membrane), my work demonstrated that physiological distension (7-37 mmHg) accelerated spheroid adhesion and spreading. Particle image velocimetry revealed that distension can increase cellular fluidization asymmetrically—2.5-fold greater in cancer cells than in mesothelia—while disrupting mesothelial collective coordination. Sustained distension decreased mesothelial viability by more than 3.5-fold over 48 hours, thereby creating permissive gaps for invasion. These findings established mechanical forces as a critical driver of peritoneal metastasis. Finally, the fifth chapter explored therapeutic rebalancing of intercellular competition through redox-sensitive anion transporters. A library of palindromic, disulfide-based peptides was synthesized and characterized by my collaborators, with the lead compound 1d (tryptophan-flanked cystine) demonstrating selective NO₃⁻/Cl⁻ antiport across lipid membranes (EC₅₀ = 3.5 μM). The disulfide bond conferred a type of redox sensitivity, as reduction to thiol decreases activity by a factor of four. Importantly, I experimentally demonstrated that 1d can exhibit differential cytotoxicity, selectively reducing the viability of triple-negative breast cancer cells (MDA-MB-231, IC₅₀ = 80.6 μM) compared with normal breast cells (MCF-10A, IC₅₀ = 106.0 μM). In competitive cocultures, 1d promoted normal cell proliferation while suppressing cancer cell growth, thereby providing proof of concept for redox-targeted selective pressure. My thesis makes several important contributions: (1) establishing mechanistic links between systemic metabolic disease and cancer progression through stromal glycation; (2) identifying mechanical distension as an active driver—not mere symptom—of metastasis; (3) developing an advanced organ-on-chip platform that enables precise mechanobiological investigation; (4) identifying GLO-1 as a therapeutic vulnerability in dicarbonyl-stressed microenvironments; and (5) demonstrating feasibility of redox-sensitive therapeutic strategies that exploit cancer-specific biochemistry. By integrating concepts from mechanobiology, active-matter physics, traction force dynamics, and developmental competition theory, my work positions intercellular competition as a central organizing principle for our understanding of cancer-stromal interactions, with profound implications for precision oncology. My findings suggest that effective therapeutic strategies must address not only cancer cell-intrinsic vulnerabilities but also microenvironmental factors that modulate the competitive fitness landscape, pointing toward combination approaches that integrate GLO-1 inhibition with chemotherapy, aggressive ascites management with targeted therapies, and redox-sensitive agents with immunotherapy. Ultimately, my thesis highlights that cancer metastasis is an emergent phenomenon of competitive dynamics at the ecosystem level, wherein microenvironmental stresses act as selective pressures that enrich for cancer fitness while eliminating stromal defenders. This perspective fundamentally reshapes how we conceptualize and target metastatic disease.