RNA-Binding Protein with Multiple Splicing (RBPMS) is a member of a family of proteins that bind to the nascent RNA transcripts and regulate their processing, which includes pre-mRNA splicing and transport/localization/stability of the RNA molecule. Evidence indicates that RBPMS also binds to members of the AP-1 (c-Jun and c-Fos) transcription factor repressing his activity. Until now, little is known about the biological function of RBPMS in ovarian cancer. To understand the role of RBPMS in ovarian cancer we generated CRISPR (clustered regularly interspaced short palindromic repeats)-mediated RBPMS knock-out vectors that were stably transfected in the ovarian cancer cells OVCAR3. The Guide-it Genotype confirmation Kit was used to determine the type of mutations (monoallelic, biallelic, or unchanged) present in the developed clones. Additionally, resulting CRISPR-cleavage products were analyzed to establish the cleavage efficiency of the Cas9/sgRNA complex by densitometry analysis. We found that CRISPR clone cells grow faster and increase their invasiveness ability compared with control CRISPR cells. Furthermore, immunohistochemical (IHC) analysis in a tissue array showed that RBPMS staining was significantly lower in high-grade serous ovarian cancer (HGSOC) tissues as compared to normal ovarian tissues. RBPMS was also decreased in platinum-resistant ovarian cancer cells as compared to platinum-sensitive cancer cells. Senescence-associated β-galactosidase (β-Gal) levels were higher in CRISPR-clones as compared with empty vector and ovarian cancer cells, which suggest RBPMS knockdown induces senescence. These studies along with the data of proteomics and RNAseq suggest that RBPMS acts as a tumor suppressor gene and lower levels of RBPMS are associated with the cisplatin resistance of ovarian cancer cells.

Citation Format: Rohit K. Sharma, Ginette S. Santiago-Sánchez, Robert J. Rabelo-Fernández, Blanca I. Quiñones-Díaz, Fatima Valiyeva, Pablo E. Vivas-Mejia. Crispr/cas-9-mediated genome editing reveals that RBPMS acts as a tumor suppressor in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2503.