(165e) A Comparative Assessment of the Response of Primary and Metastatic Ovarian Cancer Cells to Cisplatin in 3D Models of Various Structural and Biochemical Configurations

INTRODUCTION: Termed as the ‘silent killer’, epithelial ovarian cancer (EOC) earns its nickname due to its high mortality rate, with 5-year survival rates of only 46%, 46.5% and 38% in UK, USA & Europe respectively (www.cancerresearchuk.org, www.ocrahope.org). This has been attributed to some extent to the EOC’s high recurrence rate and resistance to currently available platinum based chemotherapeutic treatment methods. Hence, society, researchers and the clinical community are in dire need for a more in-depth study of the EOC microenvironment, to design better patient specific treatments and to advance current therapeutic methods. Multiple groups have studied and reported the effect of chemotherapeutic agents on various EOC 3D in vitro models (spheroids and hydrogels) ^1,2,3. However, there are very few studies wherein a direct comparative study has been carried out between the different in vitro 3D models of EOC and the effect of chemotherapy within them. Such comparative evaluation is of particular importance, especially as different 3D in vitro systems capture different structural, biochemical and biomechanical aspects of the tissue microenvironment.

Herein, we report, for the first time, a comprehensive comparative study of three different 3D in vitro platforms, namely (i) spheroids, (ii) synthetic hydrogels of various chemical configurations and (iii) polymeric scaffolds of various Extracellular Matrix (ECM) coating on the cell growth and response to the chemotherapeutic (Cisplatin) for ovary derived (A2780) and metastatic (SK-OV-3) EOC cell lines.

METHODS: Spheroids of A2780 (primary ovarian cancer) and SK-OV-3 (metastatic ovarian cancer) cell lines were fabricated using specialized 96 well round bottom plates, provided by faCellitate (Manheim, Germany). Synthetic PeptiGels (Manchester BIOGEL, UK) were used as per manufacturer’s instructions for the hydrogel based culture while polyurethane (PU) scaffold assisted 3D cultures was carried out as per our previously published protocol^4,5,6,7. The 3D cultures were maintained and monitored for different time periods (10–28 days) depending on the culture platform type. Feasibility of using these models for assessment of chemotherapeutic agent (Cisplatin) was also carried out. Various in situ assays for monitoring the cell viability, cellular apoptosis and spatial organisation were performed using advanced CLSM microscopy

RESULTS & CONCLUSION: We report that all three 3D models can support the growth of EOC, but for different time periods (varying from 7 days to 4 weeks). We have seen that chemoresistance to Cisplatin, in vitro, observed especially for metastatic EOC cells, is platform dependent both in terms of structural as well as in terms of biochemical composition of the model/platform. Our study highlights the selection of the appropriate/best 3D in vitro model depends on the cell type, experimental time period and experimental question being asked as different models are appropriate even when studying. Our study highlights that the selection of a 3D in vitro platform depends on (i) the planned experimental/assessment time period, (ii) the type of cell to be studied, (iii) the site of cell origin in vivo and (iv) the question that needs to be answered ⁸.

ACKNOWLEDGMENT: The project was supported financially by the 3DBioNet (UKRI). E.V is grateful to the Royal Academy of Engineering for an Industrial Fellowship and to the Medical Research Council UK for a New Investigator Research Grant (MR/V028553/1), which also financially supports P.G.

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