Abstract
Polybromo-1 (PBRM1) is a component of the PBAF (Polybromo-associated-BRG1- or BRM-associated factors) chromatin remodeling complex and is the second most frequently mutated gene in clear-cell renal cell Carcinoma (ccRCC). Mutation of PBRM1 is believed to be an early event in carcinogenesis, however its function as a tumor suppressor is not understood. In this study, we have employed Next Generation Sequencing to profile the differentially expressed genes upon PBRM1 re-expression in a cellular model of ccRCC. PBRM1 re-expression led to upregulation of genes involved in cellular adhesion, carbohydrate metabolism, apoptotic process and response to hypoxia, and a downregulation of genes involved in different stages of cell division. The decrease in cellular proliferation upon PBRM1 re-expression was confirmed, validating the functional role of PBRM1 as a tumor suppressor in a cell-based model. In addition, we identified a role for PBRM1 in regulating metabolic pathways known to be important for driving ccRCC, including the regulation of hypoxia response genes, PI3K signaling, glucose uptake, and cholesterol homeostasis. Of particular novelty is the identification of cell adhesion as a major downstream process uniquely regulated by PBRM1 expression. Cytoskeletal reorganization was induced upon PBRM1 reexpression as evidenced from the increase in the number of cells displaying cortical actin, a hallmark of epithelial cells. Genes involved in cell adhesion featured prominently in our transcriptional dataset and overlapped with genes uniquely regulated by PBRM1 in clinical specimens of ccRCC. Genes involved in cell adhesion serve as tumor suppressor and maybe involved in inhibiting cell migration. Here we report for the first time genes linked to cell adhesion serve as downstream targets of PBRM1, and hope to lay the foundation of future studies focusing on the role of chromatin remodelers in bringing about these alterations during malignancies.
| Original language | English (US) |
|---|---|
| Article number | e0153718 |
| Journal | PloS one |
| Volume | 11 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2016 |
Funding
The American Cancer Society Institutional Research Grant (ACS IRG #58-006-53) to the Purdue University Center for Cancer Research is gratefully acknowledged. Sanger sequencing and Cell cycle/apoptosis data were acquired by the Purdue Genomics Facility and Flow Cytometry Facility supported by P30 CA023168. ECD is supported by a V scholar award (14109042) from the V foundation. NIH Shared Instrumentation Grant, NCRR 1 S10 RR023734-01A1 supported the imaging using Zeiss LSM 710 confocal microscope. We thank Dr. Pete Pascuzzi for help in revising R script used for bioinformatics analysis, Dr. Daniel Suter for sharing his experience in imaging actin organization and helping us interpret our observations, Ms. Anwesha Sanyal and Ms. Mikala Hillis for serving as observers in the blinded tests for counting cells with cortical actin, Dr. Seema Mattoo for providing cleaved-PARP antibody,Dr.Valentina Pirro for an insightful discussion about CE data analysis.
ASJC Scopus subject areas
- General
