SQLE inhibition suppresses the development of pancreatic ductal adenocarcinoma and enhances its sensitivity to chemotherapeutic agents in vitro.

Purpose: In this study, we sought to explore the function of seven important enzymes (MSMO1, EBP, HMGCS1, IDI2, DHCR7, FDFT1, and SQLE) involved in cholesterol biosynthesis especially SQLE in PDAC therapy.

Methods And Results: The TCGA and Oncomine dataset were used to explore the expression of the seven enzymes in normal and cancerous pancreatic individual, and their anti-proliferation efficiency against PDAC cells was measured by cell viability assay. Expression level and prognostic values of SQLE were evaluated by western blot and Kaplan-Meier analysis. The influence of SQLE knockdown by shRNA in PDAC cells was assessed by transwell, colony formation and cell cycle analysis. RNA-seq and GSEA were utilized to investigate the potential mechanisms. The synergistic effect of SQLE inhibitor, terbinafine, combined with six chemotherapeutic drugs in PDAC cells was tested by CCK-8 method. We demonstrated that downregulation of those enzymes especially SQLE significantly suppressed PDAC cells survival. SQLE was upregulated in PDAC cell lines, and the elevated level of SQLE was correlated with poor prognosis in pancreatic cancer samples. SQLE knockdown could significantly inhibit the proliferation and migration of PDAC cells. Cell cycle was blocked in S phase after SQLE silencing. Mechanistically, GSEA analysis with RNA-seq data revealed that SQLE silencing negatively mediated mTORC1 and TNFα/NF-κB signaling pathways. Besides, SQLE inhibitor terbinafine enhanced chemotherapeutic sensitivity of the six compounds.

Conclusions: This study demonstrated that SQLE was a novel target for PDAC therapy. The synergism role of SQLE inhibition and chemotherapy may be potential therapeutic strategy for pancreatic cancer treatment.