OncoTargets and Therapy (Nov 2019)
Interaction Of c-Jun And HOTAIR- Increased Expression Of p21 Converge In Polyphyllin I-Inhibited Growth Of Human Lung Cancer Cells
Abstract
YueYang Zhao,1,2 XiaoJuan Tang,1 Yuhua Huang,3 Qing Tang,1 ChangJu Ma,1 Fang Zheng,1 WanYin Wu,4 Swei Sunny Hann1 1Laboratory of Tumor Biology; 2Department of Hematology; 3Department of Stomatology; 4Department of Medical Oncology, The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong Province 510120, People’s Republic of ChinaCorrespondence: Swei Sunny Hann; WanYin WuLaboratory of Tumor Biology, The Second Clinical College of Guangzhou University of Chinese Medicine, No. 111 Dade Road, Guangzhou, Guangdong Province 510120, People’s Republic of ChinaTel +8620-39318472Email [email protected]; [email protected]: Lung cancer is a leading cause of cancer-related death worldwide. Previously we demonstrated that polyphyllin I (PPI), a bioactive component extracted from Paris polyphylla, inhibited the growth of non-small cell lung cancer (NSCLC) cells through the SAPK/JNK-mediated suppressing p65, DNMT1 and EZH2 expressions. However, the molecular mechanism underlying anti-lung cancer effect by PPI still remain elusive.Purpose: In this current study, we further explored the molecular mechanism underlying the anti-lung cancer effect of PPI.Methods: MTT, Cell-LightTM EdU DNA cell proliferation and colony formation assays were used to measure cell growth. Western blot were used to examine protein levels of c-Jun and p21. The expression level of long non-codingth RNA HOX transcript antisense RNA (HOTAIR) was measured by qRT-PCR. The p21 promoter activity was measured by Dual-Luciferase Reporter Assay System. The transient transfection experiments were used to silence and overexpression of c-Jun, p21 and HOTAIR. Tumor xenograft and bioluminescent imaging experiments were carried out to confirm the in vitro findings.Results: We showed that PPI suppressed growth of NSCLC cells. Mechanistically, we observed that PPI reduced expression of HOTAIR, while increased transcription factor c-Jun protein levels. Additionally, PPI also induced protein expression and promoter activity of p21, a cyclin-dependent kinase inhibitor. While exogenously expressed HOTAIR showed no effect on c-Jun levels, silencing of c-Jun significantly reversed the PPI-inhibited HOTAIR expression. Moreover, excessive expressed c-Jun further enhanced PPI-inhibited HOTAIR expression and PPI-induced p21 protein levels. Intriguingly, overexpression of HOTAIR and silencing of c-Jun overcame the PPI-induced p21 protein and promoter activity. Finally, silencing of p21 neutralized the PPI-inhibited cell proliferation. Similar results were also found in one xenograft mouse model.Conclusion: Our results demonstrate that PPI inhibits growth of NSCLC cells through regulation of HOTAIR and c-Jun expressions, which lead to induction of p21 gene. The interactions among HOTAIR, c-Jun and p21 regulatory axis converge in the overall anti-lung cancer effect of PPI. This study unveils an additional new mechanism for the anti-lung cancer role of PPI. Keywords: PPI, NSCLC, HOTAIR, c-Jun, p21
