TKP, a Serine Protease from Trichosanthes kirilowii, Inhibits Cell Proliferation by Blocking Aerobic Glycolysis in Hepatocellular Carcinoma Cells

Abstract

Aim

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. TKP is a serine protease extracted from the fruit of Trichosanthes kirilowii. We investigated the impact of TKP on the proliferation of HCC cells and its underlying mechanisms.

Methods

Bel-7402 and HepG2 cell viability and colony formation capacity were evaluated using MTT and colony formation assays, respectively. Glucose uptake and lactate production were determined using glucose and lactate assay kits. The mRNA expressions of GLUT1, PDK, LDHA, PKM2, β-catenin, c-Myc, and HnRNPA1 were assessed using real-time PCR analysis. Protein expression and the distribution of PKM2 were examined by western blot assay.

Results

TKP significantly inhibited Bel-7402 and HepG2 cell survival and colony formation capacity. The IC50 values of TKP against Bel-7402 and HepG2 cells were 31.37 ± 1.33 and 27.41 ± 0.81 μg/mL, respectively. TKP restrained aerobic glycolysis. TKP decreased the expression level, nuclear protein level and pyruvate kinase activity of PKM2, whereas overexpression PKM2 reversed the suppression of TKP on glycolysis. TKP inhibited the β-catenin/c-Myc/HnRNPA1 pathway. LiCl treatment partly rescued the inhibitory effects of TKP on PKM2, aerobic glycolysis, and cell viability.

Conclusion

TKP suppresses HCC cell proliferation via blocking PKM2-dependent glycolysis, which is regulated by inhibiting the β-catenin/c-Myc/HnRNPA1 pathway.

Disclosure statement

No potential conflicts of interest were disclosed.

Additional information

Funding

This work was supported by the National Natural Sciences Foundation of China (No. 21207084) and Shanxi Province Key RESEARCH and Development Plan (Agriculture) Project (201903D221069) University Science.