JOURNAL OF SHANGHAI JIAOTONG UNIVERSITY (MEDICAL SCIENCE) ›› 2021, Vol. 41 ›› Issue (7): 858-864.doi: 10.3969/j.issn.1674-8115.2021.07.003

• Basic research • Previous Articles    

Function of branched-chain amino acid catabolism in lung cancer cells

Yan-qi HE1,2(), Rui CHI1,2, Meng-ping CHEN1,2, Si CHEN1,2, Chun-liang LIU1,2, Yun-xia LIU1,2, Hai-peng SUN1,2()   

  1. 1.Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University College of Basic Medical Sciences, Shanghai 200025, China
    2.Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200050
  • Online:2021-07-28 Published:2021-08-03
  • Contact: Hai-peng SUN E-mail:jenniehyq@163.com;sun.haipeng@yahoo.com
  • Supported by:
    National Natural Science Foundation of China(81570717);Basic Research Projects of Shanghai Science and Technology Innovation Action Plan(16JC1404400)

Abstract: Objective

·To explore the function and mechanism of branched-chain amino acid (BCAA) catabolism in lung cancer cells.

Methods

·Small interfering negative control (siNC) and small interfering branched-chain keto acid dehydrogenase kinase (siBCKDK) were transfected into non-small cell lung cancer cells H1299, A549 and HCC827 by instantaneous transfection. The expression of BCKDK, branched-chain keto acid dehydrogenase e1, α polypeptide (BCKDE1α) and its phosphorylation in siNC group and siBCKDK group were detected by Western blotting. The proliferation activity of the above two groups of cells was detected by CCK-8 assay. The above three kinds of cells were cultured in culture medium containing 0, 100, 200 μmol/L BT2 (3, 6-dichlorobenzo[b]thiophene-2-carboxylic acid), respectively. The expression of BCKDE1α and its phosphorylation were detected by Western blotting. The proliferation activity of 0 μmol/L BT2 group and 200 μmol/L BT2 group was detected by CCK-8 assay. The cell viability of siNC group and siBCKDK group, 0 μmol/L BT2 group and 200 μmol/L BT2 group in H1299 and A549 cells was calculated by trypan blue staining. Cell number at different phases of cell cycle was detected by propidium iodide staining. Cyclin-dependent kinase inhibitor 1A (P21) expression was detected by Western blotting.

Results

·In H1299, A549 and HCC827 cells, compared with siNC group, expression of BCKDK and phosphorylation of BCKDE1α in siBCKDK group were down-regulated, and the proliferation activity was decreased (all P=0.000). Compared with 0 μmol/L BT2 group, the phosphorylation of BCKDE1α was down-regulated in H1299, A549 and HCC827 cells in both 100 μmol/L BT2 group and 200 μmol/L BT2 group, but more obviously in 200 μmol/L BT2 group. The cell proliferation activity in 200 μmol/L BT2 group was decreased compared with that in 0 μmol/L BT2 group (all P=0.000). There was no significant difference in the cell viability of H1299 and A549 cells between siBCKDK group and siNC group, 200 μmol/L BT2 group and 0 μmol/L BT2 group, but G0/G1 cell cycle arrest occurred (all P<0.05) with the expression of P21 increasing.

Conclusion

·siBCKDK and BT2 can promote the dephosphorylation of BCKDE1α and accelerate the catabolism of BCAA, which may inhibit the proliferation of lung cancer cells by up-regulating P21 and blocking cell cycle.

Key words: branched-chain amino acids (BCAA), lung cancer, cell proliferation

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