Purpose: To research the effects of ATP citrate lyase (ACLY) and Sterol-regulatory element binding protein 1 (SREBP1) on the biology and lipid metabolism of colorectal cancer cells.
Methods: Colorectal cancer cells Caco-2 and Lovo were transfected with ACLY  or SREBP1  gene knockdown lentiviruses. Four groups were set: ACLY  knockdown, SREBP1  knockdown group, empty vector-transfected (negative control), and untreated cells (blank control). Cell proliferation was measured using CCK-8, colony formation, and EdU labeling assays. Apoptosis was detected using Annexin V-APC/7- AAD and JC-1 assay. Transwell migration and wound healing assays analyzed cell migration and invasion. A triglyceride test kit and oil red O stain assessed cell lipid production. Key factors related to lipid metabolism were detected.
Results: ACLY  and SREBP1  promoted cell proliferation at 48 and 120 h, but there was no significant difference in Caco-2 cells at 24 h, at which point the effect of SREBP1  was more important. ACLY ’s effect on cell proliferation was more obvious at 120 h. Colony formation assays in Caco-2 showed similar results to the CCK-8 assay at 120 h, but ACLY  knockdown had no effect in Lovo cells. EDU assays showed that ACLY  or SREBP1  facilitated DNA reproduction in the two cell lines, in which SREBP1  was more significant. Knockdown of the two genes showed significant differences in Lovo cells. However, ALCY  knockdown promoted apoptosis to a greater extent than SREBP1  knockdown in Caco-2 cells. In addition, ACLY  and SREBP1  enhanced migration, invasion, and lipid production in both cell lines. Knockdown of ACLY  or SREBP1  reduced lipid metabolism pathway gene expression in the two cell lines.
Conclusion: Knockdown of ACLY  and SREBP1  genes inhibit the proliferation, migration, and invasion of colorectal cancer cells, while promoting their apoptosis. Our results identified potential new targets to treat colorectal cancer via lipid synthesis modulation in cancer cells.
Keywords: ATP-citrate lyase, colorectal cancer, lipid metabolism, sterol-regulatory element binding protein 1