Metformin sensitises hepatocarcinoma cells to methotrexate by targeting dihydrofolate reductase

Abstract

Metformin, the first-line drug for type II diabetes, has recently been considered an anticancer agent. However, the molecular target and underlying mechanism of metformin’s anti-cancer effects remain largely unclear. Herein, we report that metformin treatment increases the sensitivity of hepatocarcinoma cells to methotrexate (MTX) by suppressing the expression of the one-carbon metabolism enzyme DHFR. We show that the combination of metformin and MTX blocks nucleotide metabolism and thus effectively inhibits cell cycle progression and tumorigenesis. Mechanistically, metformin not only transcriptionally represses DHFR via E2F4 but also promotes lysosomal degradation of the DHFR protein. Notably, metformin dramatically increases the response of patient-derived hepatocarcinoma organoids to MTX without obvious toxicity to organoids derived from normal liver tissue. Taken together, our findings identify an important role for DHFR in the suppressive effects of metformin on therapeutic resistance, thus revealing a therapeutically targetable potential vulnerability in hepatocarcinoma.

A statistical framework for high-content phenotypic profiling using cellular feature distributions

“…Active (dose-insensitive). Methotrexate (MTX) is a chemotherapeutic agent that inhibits DNA synthesis by targeting dihydrofolate reductase 47 , an enzyme needed for biosynthesis of nucleic acid precursors and some amino acids. MTX elicits strong phenotypic effects that are relatively consistent across all seven doses (Fig.…”

Three-Dimensional Hepatocyte Spheroids: Model for Assessing Chemotherapy in Hepatocellular Carcinoma

“…On the other hand, methotrexate interrupts one-carbon metabolism by inhibiting the synthesis of tetrahydrofolate, thereby inhibiting the synthesis of purines and thymidines, impairing cell cycle progression. Cells become resistant by overcoming this limitation, for instance, by overexpressing enzymes of the one-carbon metabolism [ 80 ]. Finally, dacarbazine, an alkylating agent commonly used in combination with other chemotherapeutic agents, may act as a purine analog and antimetabolite.…”