Exogenous hydrogen sulfide promotes hepatocellular carcinoma cell growth by activating the STAT3-COX-2 signaling pathway

Yulan Zhen; Qiaomei Wu; Yiqian Ding; Wei Zhang; Yuansheng Zhai; Xiaoxiong Lin; Yunxia Weng; Ruixian Guo; Ying Zhang; Jianqiang Feng; Yiyan Lei; Jingfu Chen

doi:10.3892/ol.2018.8154

Exogenous hydrogen sulfide promotes hepatocellular carcinoma cell growth by activating the STAT3-COX-2 signaling pathway

Oncol Lett. 2018 May;15(5):6562-6570. doi: 10.3892/ol.2018.8154. Epub 2018 Mar 2.

Authors

Yulan Zhen¹, Qiaomei Wu², Yiqian Ding³, Wei Zhang⁴, Yuansheng Zhai⁴, Xiaoxiong Lin⁴, Yunxia Weng⁴, Ruixian Guo⁵, Ying Zhang⁶, Jianqiang Feng⁵, Yiyan Lei⁷, Jingfu Chen⁸

Affiliations

¹ Department of Oncology, The Third People's Hospital of Dongguan Dongguan City, Guangdong 523326, P.R. China.
² Department of Anesthesiology, Oral Subsidiary Sun Yat-Sen University Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510700, P.R. China.
³ Grade 2013, Medical Imaging, The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong 510000, P.R. China.
⁴ Department of Cardiovasology and Cardiac Care Unit, Huangpu Division of The First Affiliated Hospital, Guangzhou, Guangdong 510080, P.R. China.
⁵ Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510700, P.R. China.
⁶ Department of Oncology, Affiliated Hospital, Guangdong Medical College, Zhanjiang, Guangdong 524001, P.R. China.
⁷ Department of Thoracic Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510080, P.R. China.
⁸ Department of Cardiovascular Medicine and Dongguan Cardiovascular Institute, The Third People's Hospital of Dongguan City, Dongguan, Guangdong 523326, P.R. China.

Abstract

The effects of hydrogen sulfide (H₂S) on cancer are controversial. Our group previously demonstrated that exogenous H₂S promotes the development of cancer via amplifying the activation of the nuclear factor-κB signaling pathway in hepatocellular carcinoma (HCC) cells (PLC/PRF/5). The present study aimed to further investigate the hypothesis that exogenous H₂S promotes PLC/PRF/5 cell proliferation and migration, and inhibits apoptosis by activating the signal transducer and activator of transcription 3 (STAT3)-cyclooxygenase-2 (COX-2) signaling pathway. PLC/PRF/5 cells were treated with 500 µmol/l NaHS (a donor of H₂S) for 24 h. The expression levels of phosphorylated (p)-STAT3, STAT3, cleaved caspase-3 and COX-2 were measured by western blot assay. Cell viability was detected by Cell Counting kit-8 assay. Apoptotic cells were observed by Hoechst 33258 staining. The expression of STAT3 and COX-2 messenger RNA (mRNA) was detected by semiquantitative reverse transcription-polymerase chain reaction. The production of vascular endothelial growth factor (VEGF) was evaluated by ELISA. The results indicated that treatment of PLC/PRF/5 cells with 500 µmol/l NaHS for 24 h markedly increased the expression levels of p-STAT3 and STAT3 mRNA, leading to COX-2 and COX-2 mRNA overexpression, VEGF induction, decreased cleaved caspase-3 production, increased cell viability and migration, and decreased number of apoptotic cells. However, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 (an inhibitor of STAT3) or 20 µmol/l NS-398 (an inhibitor of COX-2) for 24 h significantly reverted the effects induced by NaHS. Furthermore, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 markedly decreased the NaHS-induced increase in the expression level of COX-2. By contrast, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 20 µmol/l NS-398 inhibited the NaHS-induced increase in the expression level of p-STAT3. In conclusion, the findings of the present study provide evidence that the STAT3-COX-2 signaling pathway is involved in NaHS-induced cell proliferation, migration, angiogenesis and anti-apoptosis in PLC/PRF/5 cells, and suggest that the positive feedback between STAT3 and COX-2 may serve a crucial role in hepatocellular carcinoma carcinogenesis.

Keywords: COX-2; PLC/PRF/5 cells; STAT3; growth; hydrogen sulfide.