Research Projects

Despite the recent advancements in the therapeutics of oral squamous cell carcinoma (OSCC), the patient prognosis has not shown a drastic betterment. One of the foremost obstacles in achieving significant improvement in prognosis is the acquisition of therapy resistance by the tumors. Cancer stem cells (CSCs) have been widely hypothesized as major players in the development of chemoresistance by tumors. The CSCs escape the chemotherapy due to their quiescent nature, resulting in tumor relapse. However, the molecular signaling mechanism behind the acquisition of these properties by CSCs still remains largely indeterminate. In this study, we plan to explore the molecular signaling mechanism behind the acquisition of chemo-resistance by OSCC CSCs. We have previously established three advanced-stage treatment naïve patient-derived OSCC cell lines along with the respective patient-derived fibroblast for all them. Thede cell lines will be treated with a combination of three chemotherapeutic drugs that are being used in the clinic viz. Cisplatin, Docetaxel and 5-Fluorouracil to develop clinically relevant triple drug-resistant cell lines. Further, a combination of CSC markers ALDHBright/CD44+/CD133+ will be used to identify the CSCs from these models. We will explore the transcriptome profiles of the CSCs isolated from chemoresistant OSCC cell lines by RNA-seq in three ways such as a) Chemoresistant cell line culture in absence of CAF b) Chemoresistant cell line culture in presence of CAF and c) Chemoresistant cell line grown in vivo in NOD/SCID mice to unravel the effect of tumor microenvironment on the chemoresistant cell lines. The molecular signatures over-expressed in the CSCs as compared to non-CSCs will be validated by doing shRNA mediated knock-down in the clinically relevant triple drug resistant cell lines. We will assess the impact of the knock-down on the CSCs by performing the in-vitro and in-vivo characterization. Additionally, we will explore the epigenetic landscape of the CSCs by profiling the histone modifications and Chip-qPCR analysis in CSCs obtained from the aforementioned three combinations. Futher, the findings of the expression profiling will also be validated in 360 retrospective neo-adjuvant chemotherapy (NACT) treated patient samples in regard to the Recist criteria. Pre-NACT and post-NACT biopsies will be collected from the patient tumors, and expression of CSCs molecular signatures will be evaluated in these tissues. This study will provide valuable insights into the molecular signaling mechanism, tumor microenvironment, and epigenetic landscape behind the acquisition of chemotherapy resistance by OSCC CSCs in the absence and presence of tumor micro-environment i.e., CAF. Further, these CSCs molecular signatures will be validated in the large cohort of Pre-NACT and Post-NACT patient samples in regard to the Overall survival (OS) and Progression-free survival (PFS) of the patients.