Phenyl Isothiocyanate Inhibit the Expression of c-Myc and RPS19 in Non-Small Cell Lung Cancer Cells via the PI3K/Akt/mTOR Pathway

HU Jun¹, XU Lili², LUO Yi¹, XIE Yong¹, GAO Wenkui¹, CHEN Yanhua², WANG Baiqi²*

(¹Department of thoracic surgery, the Second Hospital University of Sounth China, Hengyang 421001, China; ²Department of hematology of tumor, the Second Hospital University of Sounth China, Hengyang 421001, China)

Abstract:

The aim of this study was to investigate the mechanism of PEITC (phenethyl isothiocyanate) on the inhibition of c-Myc and RPS19 expression in non-small cell lung cancer cells. A549, H358 and H1299 cell lines were cultured in vitro. The expression levels of intracellular RPS19 (ribosomal protein S19) and c-Myc were determined by Western blot and qPCR. After treatment with 10, 30 and 50 μmol/L PEITC, the expression levels of intracellular RPS19, c-Myc, E-cadherin, Vimentin and phosphorylation of PI3K/Akt, mTOR and S6K were detected by Western blot. The activity of RPS19 promoter reporter gene was detected by constructing pGL4.10-RPS19 fluorescent reporter vector. The expression levels of intracellular RPS19, c-Myc were detected after treatment with c-Myc, PI3K/Akt and mTOR inhibitors. After that, the pcDNA3-c-Myc-HA plasmid was transfected into the cells to observe the effect of c-Myc on the expression of RPS19. The intracellular level of RPS19 was silenced by siRNA. The expression of E-cadherin, Vimentin, and the invasion and migration of the cells were analyzed. Western blot and qPCR results showed that RPS19 and c-Myc were highly expressed in A549 and H1299 cell lines. After treatment with different concentrations of PEITC, the expression levels of intracellular RPS19, c-Myc, Vimentin, and the phosphorylation levels of PI3K/Akt, mTOR and S6K were significantly decreased, while the E-cadherin level was significantly increased. In addition, pretreatment of the PI3K/Akt and mTOR inhibitors significantly reduced the expression of intracellular RPS19 and c-Myc. And the c-Myc inhibitors could also reduce the intracellular level of RPS19 and its transcriptional activity. Over-expression of c-Myc by transfection of the pcDNA3-cMyc-HA plasmid significantly increased the level of intracellular RPS19, while silencing the RPS19 by siRNA could increase the intracellular E-cadherin expression and inhibit the cells invasion and migration. These results demonstrate that PEITC can inhibit the expression of c-Myc and RPS19 in non-small cell lung cancer H1299 cells, which may be related to the inhibition of PI3K/Akt/mTOR signaling pathway.