Resveratrol induces apoptosis in human melanoma cell through negatively regulating Erk/PKM2/Bcl-2 axis

OncoTargets and Therapy, Dec 2018

Resveratrol induces apoptosis in human melanoma cell through negatively regulating Erk/PKM2/Bcl-2 axis Hailong Zhao,1 Limin Han,1 Yi Jian,2 Yuntao Ma,3 Wanyue Yan,3 Xiaowen Chen,1 Haiyan Xu,1 Lijuan Li1 1Department of Pathophysiology, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China; 2The First Clinical Institute, The School of Medicine and Science, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China; 3The First Clinical Institute, The Department of Clinical Medicine, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China Background: Resveratrol is known as a natural phytoalexin found in grapes and wine, which has significant antitumor activity under in vitro and in vivo conditions. In recent years, great progress has been made in understanding the underlying mechanisms of resveratrol in inducing cellular apoptosis of melanoma cells. Our previous study has shown that the apoptosis regulation of resveratrol in melanoma cells was independent of activation of classical apoptosis-related protein p53. Materials and methods: MTT assay and 5-bromo-2'-deoxyuridine staining assay were used to analyze cell viability and proliferation. Immunofluorescence analysis of γ-H2AX was employed to clarify DNA damages. Annexin V–propidine iodide/fluorescein isothiocyanate assay was performed to evaluate the cell apoptosis. The mechanisms underlying the activation of M2-type pyruvate kinase (PKM2) by Erk1/2 to stabilize and maintain Bcl-2 signaling was investigated by subcellular fractionation analyses, immunofluorescence analysis, co-immunoprecipitation assay, ubiquitination assay, and glutathione S-transferase pull-down assay. Results: In the present study, we found that resveratrol dramatically inhibited melanoma cell proliferation and induced cell apoptosis through upregulation of p53 in a concentration-dependent manner. Conversely, p53 downregulation by short hairpin RNA couldn’t rescue resveratrol-induced cell proliferation inhibition or apoptosis enlargement. Additionally, we found that resveratrol downregulated antiapoptotic protein Bcl-2 and activated Bax in the protein levels by promoting Bcl-2 degradation and cytochrome c release. Moreover, we discovered that PKM2, had a key role in cell apoptosis triggered by resveratrol through interacting with Bcl-2. Based on these results, we overexpressed PKM2 in melanoma cells and found that this prevented resveratrol-induced apoptosis by stabilizing the protein level of Bcl-2. Conclusion: Taken together, our results provided a novel mechanism accounting for the apoptosis induction of resveratrol in melanoma cells and suggested that downregulating Erk/PKM2/Bcl-2 axis appears to be a new approach for the prevention or treatment of melanoma. Keywords: antitumor, ubiquitination, cytochrome c, ER stress

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Resveratrol induces apoptosis in human melanoma cell through negatively regulating Erk/PKM2/Bcl-2 axis

Authors Zhao H, Han L, Jian Y, Ma Y, Yan W, Chen X, Xu H, Li L Received 11 September 2018 Accepted for publication 14 November 2018 Published 11 December 2018 Volume 2018:11 Pages 8995—9006 DOI https://doi.org/10.2147/OTT.S186247 Checked for plagiarism Yes Review by Single-blind Peer reviewers approved by Dr Amy Norman Peer reviewer comments 3 Editor who approved publication: Dr Leo Jen-Liang Su Hailong Zhao,1 Limin Han,1 Yi Jian,2 Yuntao Ma,3 Wanyue Yan,3 Xiaowen Chen,1 Haiyan Xu,1 Lijuan Li1 1Department of Pathophysiology, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China; 2The First Clinical Institute, The School of Medicine and Science, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China; 3The First Clinical Institute, The Department of Clinical Medicine, Zunyi Medical University, Zunyi, Guizhou Province 563000, People’s Republic of China Background: Resveratrol is known as a natural phytoalexin found in grapes and wine, which has significant antitumor activity under in vitro and in vivo conditions. In recent years, great progress has been made in understanding the underlying mechanisms of resveratrol in inducing cellular apoptosis of melanoma cells. Our previous study has shown that the apoptosis regulation of resveratrol in melanoma cells was independent of activation of classical apoptosis-related protein p53. Materials and methods: MTT assay and 5-bromo-2'-deoxyuridine staining assay were used to analyze cell viability and proliferation. Immunofluorescence analysis of γ-H2AX was employed to clarify DNA damages. Annexin V–propidine iodide/fluorescein isothiocyanate assay was performed to evaluate the cell apoptosis. The mechanisms underlying the activation of M2-type pyruvate kinase (PKM2) by Erk1/2 to stabilize and maintain Bcl-2 signaling was investigated by subcellular fractionation analyses, immunofluorescence analysis, co-immunoprecipitation assay, ubiquitination assay, and glutathione S-transferase pull-down assay. Results: In the present study, we found that resveratrol dramatically inhibited melanoma cell proliferation and induced cell apoptosis through upregulation of p53 in a concentration-dependent manner. Conversely, p53 downregulation by short hairpin RNA couldn’t rescue resveratrol-induced cell proliferation inhibition or apoptosis enlargement. Additionally, we found that resveratrol downregulated antiapoptotic protein Bcl-2 and activated Bax in the protein levels by promoting Bcl-2 degradation and cytochrome c release. Moreover, we discovered that PKM2, had a key role in cell apoptosis triggered by resveratrol through interacting with Bcl-2. Based on these results, we overexpressed PKM2 in melanoma cells and found that this prevented resveratrol-induced apoptosis by stabilizing the protein level of Bcl-2. Conclusion: Taken together, our results provided a novel mechanism accounting for the apoptosis induction of resveratrol in melanoma cells and suggested that downregulating Erk/PKM2/Bcl-2 axis appears to be a new approach for the prevention or treatment of melanoma. Keywords: antitumor, ubiquitination, cytochrome c, ER stress Introduction Malignant melanoma is one of the most often diagnosed cancers originating from melanocytes.1 Over the past decades, various medical therapies for melanoma patients including surgery, radiation, and chemotherapy have been well applied, but the incidence of malignant melanoma is still increasing and the prognosis remains extremely poor.2 The few reasons for this are as follows: 1) surgical resection is useless for melanoma patients because of undetectable lesions process and numerous organs dissemination, such as brain, lung, or liver;3,4 2) in radiation there is an urgent need to exploit the efficacy of the anti-melanoma therapies owing to the damage to normal physiological mechanism and immune system;1,4,5 and 3) the incapacity of most chemotherapeutic drugs for high efficiency as a result of the intrinsic resistance to apoptosis in melanoma.6,7 Among these three therapies, chemotherapeutic therapy is relatively more controlled and easier to update.8,9 Therefore, it is time to investigate novel drugs for melanoma treatment with minimal toxicity and resistance. Although melanoma is a historically treatment-resistant malignancy, recent reports showed that antiapoptotic factors from intrinsic apoptosis pathways become potential targets for overcoming the apoptotic resistance of melanoma.7,9,10 As per our previous research, NAMPT/E2F2/SIRT1 signaling pathway among the nicotinamide adenine dinucleotide (oxidized) (NAD+)-dependent regulation network in human melanoma cells regulated cell proliferation and apoptosis resistance. However, inhibition of the NAMPT/E2F2/SIRT1 pathway was involved in but independent of p53 activation.11 At the same time, resveratrol used as a potent activator of SIRT1 through AMP- (...truncated)


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Hailong Zhao, Limin Han, Yi Jian, Yuntao Ma, Wanyue Yan, Xiaowen Chen, Haiyan Xu, Lijuan Li. Resveratrol induces apoptosis in human melanoma cell through negatively regulating Erk/PKM2/Bcl-2 axis, OncoTargets and Therapy, 2018, pp. 8995-9006, DOI: 10.2147/OTT.S186247