Knockdown of DEAD-box RNA helicase 52 (DDX52) suppresses the proliferation of melanoma cells in vitro and of nude mouse xenografts by targeting c-Myc

ABSTRACT

The ATP-dependent protein DEAD-box RNA helicase 52 (DDX52) is an important regulator in RNA biology and has been implicated in the development of prostate and lung cancer. However, its biological functions and clinical importance in malignant melanoma (MM) are still unclear. Understanding the potential mechanism underlying the regulation of MM progression by DDX52 might lead to novel therapeutic strategies. The aim of the present study was to investigate the role of DDX52 in the regulation of MM progression and its clinical relevance. DDX52 expression in normal and MM tissues was evaluated by GEO analysis and immunohistochemistry. The effects of DDX52 on cell growth were evaluated in MM cells with downregulated DDX52 expression. In this study, we found that DDX52 was markedly overexpressed in MM tissues compared with nontumor tissues and was associated with shorter overall survival in patients; therefore, DDX52 might be a prognostic marker in MM. Downregulation of DDX52 expression in the MM cell lines A2058 and MV3 markedly inhibited cell proliferation and colony formation. Additionally, knockdown of DDX52 in MM cells caused significant regression of established tumors in nude mice and delayed the onset time. Moreover, downregulation of DDX52 markedly suppressed c-Myc mRNA and protein expression, and an RNA immunoprecipitation assay confirmed the association between DDX52 and c-Myc. Restoration of c-Myc expression partly rescued the effects of DDX52 deficiency in MM cells. In conclusion, our study found that DDX52 mediated oncogenesis by promoting the transcriptional activity of c-Myc and could be a therapeutic target in MM.

Graphical Abstract

KEYWORDS:

• Melanoma
• DDX52
• c-Myc
• proliferation

Acknowledgements

Support for the present study was provided by the following: the National Natural Science Foundation of China (No. 81671915 and No. 81802724), the Young Scientist Grant of Zhongshan Hospital (No. 2019ZSYQ32), and Research & Development Grant of Zhongshan Hospital (2017ZSKY143)

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Qiang Wang and Leqi Qian performed all the experiments and prepared the manuscript, manuscript and thus should be co-first authors for their equal contributions to this paper. Jiaqi Liu and Fazhi Qi conceptualized, planned this study. Menyuan Tao helped analyze the data.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [81802724]; National Natural Science Foundation of China [81671915]; Young Scientist Grant of Zhongshan Hospital [2019ZSYQ32]; Reasearch & Development Grant of Zhongshan Hospital [2017ZSKY143].