TIGAR promotes malignant proliferation of NSCLC by modulating deoxynucleotide anabolism via a YBX1-RRM2B axis

Abstract

Abstract Background:Lung cancer is one of the most common causes of cancer-related death worldwide due to its rapid growth and metastasis. TIGAR plays a role in promoting survival in various cancer cells, but the molecular mechanisms on metabolic reprogram in tumor cells are not fully understood. Methods: TIGAR expression was detected in lung cancer by western blot and immunohistochemistry. A shRNA interference system was used to knockdown the TIGAR in NSCLC cell lines to delineate its role in NSCLC tumor proliferation using in vitro functional assays and in vivo mouse models. Finally, transcriptomics and metabolomics were used to identify the mechanism of TIGAR. Results: The expression of TIGAR in tumor tissues of NSCLC patients was significantly higher than that of adjacent tissues, which was associated with poor prognosis of NSCLC. The proliferation of NSCLC cells in vitro and the growth of xenografted tumors in vivo were significantly inhibited by TIGAR knockdown. With a combination of transcriptomics and metabolomics, we found that TIGAR maintained intracellular deoxyribonucleotide levels by regulating the expression of the ribonucleotide reductase (RNR) subunit RRM2B, a protein involved in deoxynucleotide synthesis. Further studies with LC-MS and co-immunoprecipitation revealed that TIGAR interacted with the transcription factor YBX1, participated in its phosphorylation and nuclear translocation to induce the expression of its downstream gene RRM2B. In addition, overexpression of RRM2B or exogenous supplementation of dNTPs effectively rescued the restriction of cell proliferation and DNA repair caused by TIGAR knockdown. Conclusion: The present studies revealed a novel mechanism of TIGAR in promoting the proliferation and DNA repair of NSCLC cells through maintaining the intracellular deoxynucleotide level via the YBX1-RRM2B axis.