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The effect and mechanism of sphingosine kinase-1 knockdown on non-small cell lung cancer cell proliferation and mitochondrial apoptotic pathway

CAO Yu-Hua^1,*, YIN Wu², LYN Yan-Ru³

¹Clinical Tumor Center, People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, China；²Department of Pathology, People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, China；³Ministry of Scientific Research, People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, China

Abstract

The purpose of the present study was to investigate the effect and potential mechanism of knockdown of sphingosine kinase-1 (SPHK1) on the proliferation, cell cycle and apoptosis of non-small cell lung cancer (NSCLC) cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect SPHK1 mRNA expression in human healthy lung fibroblasts (MRC-5 cells) and four NSCLC cell lines. Then, A549 and H1299 cells were transfected with SPHK1-shRNA and corresponding negative control. CCK-8, Annexin V-FITC/PI dual staining and cell cycle assay were performed to evaluate cell proliferation, apoptosis and cell cycle distribution, respectively. JC-1 mitochondrial membrane potential measurement kit was adopted to measure mitochondrial membrane potential. Western blot was used to detect the protein expression levels of cell cycle and mitochondrial apoptotic pathway- related proteins, as well as MEK/ERK signaling pathway. The results showed that the mRNA expression of SPHK1 in NSCLC cells was higher than that in MRC-5 cells. SPHK1-shRNA significantly inhibited the proliferation of A549 and H1299 cells, blocked the cell cycle in G0/G1 phase, and promoted cell apoptosis through the mitochondrial pathway. Compared with the control group, the expression of p-MEK and p-ERK proteins in the SPHK1-shRNA group was significantly down-regulated. Moreover, MEK/ERK inhibitor could dramatically suppress cell proliferation and promote cell apoptosis. These results suggest that SPHK1 knockdown can inhibit the proliferation of NSCLC cells and might promote mitochondrial apoptotic pathway by inhibiting MEK/ERK signaling pathway.

Key words: non-small cell lung cancer; sphingosine kinase-1; mitochondrial apoptotic pathway; cell cycle

Received: 2020-11-18　　Accepted: 2021-03-11

Corresponding author: 曹宇华　　E-mail: 2357064200@qq.com

Citing This Article：

CAO Yu-Hua, YIN Wu, LYN Yan-Ru. The effect and mechanism of sphingosine kinase-1 knockdown on non-small cell lung cancer cell proliferation and mitochondrial apoptotic pathway. Acta Physiol Sin 2021; 73 (6): 893-900 (in Chinese with English abstract).