The “LINC” between Δ40p53-miRNA Axis in the Regulation of Cellular Homeostasis

Abstract

Previous research has shown that Δ40p53, the translational isoform of p53, can inhibit cell growth independently of p53 by regulating microRNAs. Here, we explored the role of Δ40p53 in regulating the long noncoding RNA-micro-RNA-cellular process axis, specifically focusing on LINC00176. Interestingly, LINC00176 levels were predominantly affected by the overexpression/stress-mediated induction and knockdown of Δ40p53 rather than p53 levels. Additional assays revealed that Δ40p53 transactivates LINC00176 transcriptionally and could also regulate its stability. RNA immunoprecipitation experiments revealed that LINC00176 sequesters several putative microRNA targets, which could further titrate several mRNA targets involved in different cellular processes. To understand the downstream effects of this regulation, we ectopically overexpressed and knocked down LINC00176 in HCT116 p53–/– (harboring only Δ40p53) cells, which affected their proliferation, cell viability, and expression of epithelial markers. Our results provide essential insights into the pivotal role of Δ40p53 in regulating the novel LINC00176 RNA-microRNA-mRNA axis independent of FL-p53 and in maintaining cellular homeostasis.

Keywords:

• p53 isoform
• Δ40p53 function
• LINC00176 regulation
• lncRNA-miRNA axis
• Effect on cellular processes

ACKNOWLEDGMENTS

We acknowledge Prof. J.C. Bourdon, University of Dundee, UK and Dr Robin Fahraeus, INSERM, France, for providing the anti-p53 antibody. We thank Dr Je-Hyun Yoon and Dr Myriam Gorospe, National Institutes of Health, USA, for providing the TRAP constructs. We acknowledge Dr T Tamura, Institut fuer Biochemie, Germany, for providing LINC00176 overexpression construct and siRNA. We thank Prof. Sathees C. Raghavan for his valuable suggestions. We acknowledge Dr Debjit Khan (Post-Doctoral Research Fellow, Cleveland Clinic, USA) for his invaluable suggestions. We also thank the present and past SD lab-members for helpful discussion of the work. This work is supported by a research grant to SD from the Department of Biotechnology (DBT), Govt of India. SD also acknowledges J.C. Bose fellowship for research support. This study was also supported by the DBT-IISc partnership program. DST Fund for Improvement of Science and Technology Infrastructure (FIST) level II infrastructure and University Grants Commission Centre of Advanced Studies support is acknowledged. We thank Editage (www.editage.com) for English language editing.

AUTHOR CONTRIBUTIONS

AP and SD: Conception and design of studies, analysis and interpretation, and article writing. AP and PKG for performing the experiments.

DATA AVAILABILITY STATEMENT

All the data supporting the findings of this study are available within the main article and is also available in Figshare repository at doi:10.6084/m9.figshare.22726586.