The roles of both the endogenous synthesis and exogenous uptake of fatty acids in thyroid cancer cell proliferation.

BACKGROUND: Cancer cells fulfil their energy requirements by acquiring fatty acids (FAs) through both de novo synthesis and exogenous uptake. Although studies have focused on de novo FAs synthesis in papillary thyroid cancer (PTC), research on exogenous FAs uptake is scarce. Lipoprotein lipase (LPL), which enhances cellular FAs uptake, serves as the focal point of this study, which explored the role of LPL-mediated exogenous FAs uptake and FAs synthase (FASN)-mediated endogenous FAs synthesis in PTC cell proliferation. METHODS: The expression of LPL was analyzed using databases including GTEx, GEO, and TCGA. Furthermore, its expression in PTC tissue samples and cell lines was confirmed. To observe the impact of the lipoprotein-deficient medium on PTC cells, EdU and TUNEL staining assays were conducted. CCK-8, colony formation, and TUNEL assays were performed to assess the effect of down-regulating LPL and/or FASN expression in PTC cells. RESULTS: Bioinformatics analysis revealed the upregulation of LPL mRNA in thyroid cancer. LPL expression was significantly elevated in PTC tissues and cell lines. Lipoprotein-deficient medium inhibited PTC cell proliferation and induced apoptosis. Similarly, silencing either LPL or FASN led to comparable outcomes. The combined inhibition of both LPL and FASN had a synergistic effect, enhancing the inhibition of PTC cell proliferation and the increase in apoptosis. CONCLUSIONS: Both the de novo synthesis and exogenous uptake of FAs are important for PTC cell proliferation. The combined inhibition of LPL and FASN inhibitors shows promise for PTC treatment.