Lipids Metabolism Inhibition Antiproliferative Synergy with 5-Fluorouracil in Human Colorectal Cancer Model

Colorectal cancer (CRC) is recognized as the third most lethal cancer worldwide. While existing treatment options demonstrate considerable efficacy, they are often constrained by non-selectivity and substantial side effects. Recent studies indicate that lipid metabolism significantly influences carcinogenesis, highlighting it as a promising avenue for developing targeted anticancer therapies. The purpose of the study was to see if acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and stearoyl-CoA 9-desaturase (SCD1) are good metabolic targets and whether the use of inhibitors of these enzymes together with 5-fluorouracil (5-FU) would have a synergistic effect on CRC cell viability. To confirm that the correct lipid targets were chosen, the expression levels of ACAT1, HMGCR, and SCD1 were examined in CRC patients and cell models. At first, each compound (Avasimibe, Lovastatin, MF-438, and 5-FU was tested separately, and then each inhibitor was paired with 5-FU to assess the synergistic effect on cell viability. Gene expression of selected enzymes significantly increased in tissue samples obtained from CRC patients and cancer cell lines (HT-29). Inhibition of any of the selected enzymes reduced CRC cell growth in a dose-dependent manner. More importantly, the combination of 5-FU + Avasimibe (an ACAT1 inhibitor) and 5-FU + MF-438 (an SCD1 inhibitor) produced a stronger antiproliferative effect than the inhibitors alone. 5-FU combined either with Avasimibe or MF-438 showed a synergistic effect with an HSA score of 47.00 at a dose of 0.3 + 30 µM, respectively (2.66% viability rate vs. 46%; p < 0.001), and 39.34 at a dose of 0.3 + 0.06 µM (46% vs. 10.33%; p < 0.001), respectively. The association of 5-FU with Lovastatin (HMGCR inhibitor) did not significantly impact CRC cell viability in a synergistic manner. Inhibition of lipid metabolism combined with standard chemotherapy is a promising strategy that reduces CRC cell viability and allows for the use of a lower drug dose. The combination of 5-FU and Avasimibe has the greatest therapeutic potential among studied compounds.