Developing Clinically Relevant Acquired Chemoresistance Models in Epithelial Ovarian Cancer Cell Lines.

Chemoresistance, the ability of cancer cells to overcome therapeutic interventions, is an area of active research. Studies on intrinsic and acquired chemoresistance have partly succeeded in elucidating some of the molecular mechanisms in this elusive phenomenon. Hence, drug-resistant cellular models are routinely developed and used to mimic the clinical scenario in-vitro. In an attempt to identify the underlying molecular mechanisms that allow ovarian cancer cells to gradually acquire chemoresistance, we have developed isogenic cellular models of cisplatin and paclitaxel resistance (singularly and in combination) over six months, using a clinically relevant modified pulse method. These models serve as important tools to investigate the underlying molecular players, modulation in genetics, epigenetics, and relevant signaling pathways, as well as to understand the role of drug detoxification and drug influx-efflux pathways in development of resistance. These models can also be used as screening tools for new therapeutic molecules. Additionally, repurposing therapeutic agents approved for diseases other than cancer have gained significant attention in improving cancer therapy. To investigate the effect of metformin on acquirement of chemoresistance, we have also developed a combinatorial model of metformin and platinum-taxol, using two different strategies. All these models were subsequently used to study modulation in receptor tyrosine kinase pathways, cancer stem cell functionalities, autophagy, metastasis, metabolic signatures, and various biological processes during development of chemoresistance. Herein, we outline the protocols used for developing these intricate resistant cellular models.