Marta Overchuk

Beyond light scattering: the effects of intralipid on benzoporphyrin derivative-sensitized photodynamic treatment in ovarian cancer cells

Intralipid, a soybean oil-based lipid emulsion, is widely used in photomedicine to enhance light distribution due to its strong scattering properties. Although the optical characteristics of Intralipid are well documented, interactions with the reactive molecular species (RMS) generated during photodynamic therapy (PDT) and the impact of such interactions on therapeutic outcomes remain poorly understood. We reveal that Intralipid actively influences PDT response We examined how Intralipid affects the optical and photodynamic behavior of benzoporphyrin derivative (BPD), a clinical photosensitizer, in solution and across four ovarian cancer cell lines. The photodynamic properties of BPD, with and without Intralipid, were analyzed using fluorescence spectrometry and RMS probes, and PDT-induced oxidation of Intralipid components was characterized using LC-MS. The effects of Intralipid on BPD-PDT were evaluated under various conditions. Intralipid reduced BPD photobleaching and RMS generation, suggesting RMS quenching. Extensive oxidation of Intralipid components was observed following PDT. Finally, Intralipid significantly modified BPD-PDT efficacy across all four cell lines, depending on photosensitizer-light interval, dose, and incubation time. Intralipid acts as a bioactive modulator of PDT response, highlighting the need for further investigations both

PpIX‐enabled fluorescence‐based detection and photodynamic priming of platinum‐resistant ovarian cancer cells under fluid shear stress

AbstractOver 75% percent of ovarian cancer patients are diagnosed with advanced‐stage disease characterized by unresectable intraperitoneal dissemination and the presence of ascites, or excessive fluid build‐up within the abdomen. Conventional treatments include cytoreductive surgery followed by multi‐line platinum and taxane chemotherapy regimens. Despite an initial response to treatment, over 75% of patients with advanced‐stage ovarian cancer will relapse and succumb to platinum‐resistant disease. Recent evidence suggests that fluid shear stress (FSS), which results from the movement of fluid such as ascites, induces epithelial‐to‐mesenchymal transition and confers resistance to carboplatin in ovarian cancer cells. This study demonstrates, for the first time, that FSS‐induced platinum resistance correlates with increased cellular protoporphyrin IX (PpIX), the penultimate downstream product of heme biosynthesis, the production of which can be enhanced using the clinically approved pro‐drug aminolevulinic acid (ALA). These data suggest that, with further investigation, PpIX could serve as a fluorescence‐based biomarker of FSS‐induced platinum resistance. Additionally, this study investigates the efficacy of PpIX‐enabled photodynamic therapy (PDT) and the secretion of extracellular vesicles under static and FSS conditions in Caov‐3 and NIH:OVCAR‐3 cells, two representative cell lines for high‐grade serous ovarian carcinoma (HGSOC), the most lethal form of the disease. FSS induces resistance to ALA‐PpIX‐mediated PDT, along with a significant increase in the number of EVs. Finally, the ability of PpIX‐mediated photodynamic priming (PDP) to enhance carboplatin efficacy under FSS conditions is quantified. These preliminary findings in monolayer cultures necessitate additional studies to determine the feasibility of PpIX as a fluorescence‐based indicator, and mediator of PDP, to target chemoresistance in the context of FSS.

Photodynamic therapy simultaneously induces ferroptosis- and apoptosis-like lipid signatures in ovarian cancer cells

Abstract Resistance to apoptosis-inducing chemotherapy is a major factor contributing to treatment failure and poor survival outcomes in high-grade serous ovarian cancer (HGSOC). Ferroptosis, a regulated form of cell death driven by lipid peroxidation, has emerged as a promising effector mechanism because it remains available in HGSOC cells with impaired apoptosis signaling. While most research has focused on pharmacological ferroptosis inducers, there is growing interest in strategies that could trigger lipid autoxidation through externally delivered energy, such as photons. Photodynamic therapy (PDT), which utilizes light and light-activatable photosensitizers to generate reactive molecular species, offers a means of initiating lipid peroxidation with a high degree of precision and minimal systemic toxicities. However, the precise lipid targets of PDT, the influence of varying tumor lipidomic landscapes, and the role of ferroptosis sensitivity on PDT-lipid interactions have yet to be elucidated. In this study, we systematically compare PDT to ferroptosis induced by the inhibition of glutathione peroxidase 4, focusing on lipid redox states and composition in HGSOC cell lines. While PDT was similarly effective in both ferroptosis-sensitive and -resistant cells, its effects on cellular lipidomes differed markedly. PDT robustly induced lipid radical formation in both cell types; however, a dose-dependent accumulation of lipid hydroxides and hydroperoxides was only observed in ferroptosis-sensitive cells rich in unsaturated phospholipids. Further analysis revealed a significant overlap in lipid oxidation targets between PDT and ferroptosis. Notably, in both cell types, and in vivo, PDT upregulated ceramides, a lipid class strongly associated with mitochondrial apoptosis. In summary, PDT exhibited comparable efficacy in both ferroptosis-sensitive and -resistant cells by triggering a combination of lipid peroxidation and ceramide upregulation, suggesting the activation of both ferroptosis and apoptosis pathways. Further studies are needed to explore the role of PDT-induced lipidomic changes in the initiation of various cell death pathways and in overcoming chemoresistance in HGSOC.

Overcoming the effects of fluid shear stress in ovarian cancer cell lines: Doxorubicin alone or photodynamic priming to target platinum resistance

AbstractResistance to platinum‐based chemotherapies remains a significant challenge in advanced‐stage high‐grade serous ovarian carcinoma, and patients with malignant ascites face the poorest outcomes. It is, therefore, important to understand the effects of ascites, including the associated fluid shear stress (FSS), on phenotypic changes and therapy response, specifically FSS‐induced chemotherapy resistance and the underlying mechanisms in ovarian cancer. This study investigated the effects of FSS on response to cisplatin, a platinum‐based chemotherapy, and doxorubicin, an anthracycline, both of which are commonly used to manage advanced‐stage ovarian cancer. Consistent with prior research, OVCAR‐3 and Caov‐3 cells cultivated under FSS demonstrated significant resistance to cisplatin. Examination of the role of mitochondria revealed an increase in mitochondrial DNA copy number and intracellular ATP content in cultures grown under FSS, suggesting that changes in mitochondria number and metabolic activity may contribute to platinum resistance. Interestingly, no resistance to doxorubicin was observed under FSS, the first such observation of a lack of resistance under these conditions. Finally, this study demonstrated the potential of photodynamic priming using benzoporphyrin derivative, a clinically approved photosensitizer that localizes in part to mitochondria and endoplasmic reticula, to enhance the efficacy of cisplatin, but not doxorubicin, thereby overcoming FSS‐induced platinum resistance.