ASSESSING THE IMPACT OF GENETIC VARIATIONS ON METFORMIN EFFICACY: A COMPARATIVE STUDY OF p21 AND p53 KNOCKOUT DERIVATIVES IN HCT116 COLORECTAL CANCER CELL LINE

Abstract

Colorectal cancer (CRC) ranks as the world’s third most common cancer, with incidence risks rising with increasing age. Early-stage CRC does not present any symptoms, which often leads to advanced-stage diagnosis. The high heterogeneity in CRC reduces the efficiency of the available treatment regimens, rendering the search for alternative treatment options suitable for both early and advanced-stage CRC. Metformin, a commonly used anti-diabetic drug, is known to have potential anti-cancer effects. Studies reveal a 30- 50 % reduction in tumor incidence among people with diabetes on metformin. This study aimed to evaluate the impact of genetic variations on the efficacy of metformin in treating colorectal cancer using the HCT116 cell line, harboring KRAS mutation and its derivatives with tumor suppressor genes p53 (HCT116-p53-/-) and p21 (HCT116-p21-/-) knockouts. The preliminary analysis included microscopic visualization, trypan blue live cell counting, and flow cytometry-based cell cycle analysis. Dose-response (0.5, 1, 2, 4, and 8 mM) and time-course (24 and 48 hours) treatments were performed to determine optimal treatment conditions for RNA sequencing. Comprehensive analysis of the data revealed that the metformin efficacy varied with genetic mutations, with wild-type HCT116 showing the highest sensitivity to metformin-induced cell growth inhibition, followed by HCT116-p53- /- cell line and the HCT116-p21-/- cell line showing resistance to metformin. Differential expression analysis with pathway and gene ontology analysis uncovered a potential p53- dependency and independency underlying metformin’s mechanism of action and proposed FAM111A, DUSP5, FGD6, PLAUR, and TNFAIP3 as the possible molecular targets of metformin. These results signify the need for a precision medicine approach in treating colorectal cancer according to their genetic mutation profiles and highlight metformin’s sensitivity to treating KRAS mutations rather than the tumor suppressor gene mutations.

Date of Award	2024
Original language	American English
Awarding Institution	HBKU College of Health & Life Sciences