Abstract 4161: Rab25 cooperates with RIN1 to suppress p21 Ras

• Published in: Cancer research (Chicago, Ill.) Ill.), 2012-04, Vol.72 (8_Supplement), p.4161-4161
• Main Authors: Cheng, Jiming, Ayyagari, Vijayalakshmi, Rao, Krishna
• Format: Article
• Language: English
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM2012-4161

Introduction: Our previous work has shown that the loss of Rab25 occurs in estrogen receptor (ER) and progesterone receptor (PR) negative breast cancer cell lines and human tumor samples and seems to correlate with an active Ras pathway. Loss of Rab25 cooperates with mutant Ras to promote tumorigenesis. RIN1 is a protein inhibitor of Ras, and our current works confirms that Rab25 binds to RIN1 and cooperates to inhibit Ras. Rab25 also has multiple effects on microRNAs. Materials and Methods: Cell culture -RAO-1-4 cell lines was grown in DFCI-1 medium. Immunoprecipitation- Protein extracts from RAO-1, RAO-2, and RAO-3/Rab25 were tested for RIN1expression. Immunoprecipitated extracts were then assayed by western blot for RAB25 expression. Chemiluminescence Assay- Cell extract from MDA-MB-231 cells with shRIN1 was used. These cells contained no Rab25 as well. Recombinant RIN1 and recombinant Rab25 were tested in various combinations for ras inhibition using the Active Motif kit. MicroRNA assay- RNA was extracted from RAO-2, RAO-4, and RAO-4/Rab25 and sent to Phalanx Biotech for microRNA profiling. Results: 1. Rab25 binds to RIN1 in a ternary complex with Ras. 2. Rab25 coopeates with RIN1 in an additive manner to inhibit Ras. 3. Rab25 expression impacts several microRNAs including 29b, 100, 138, 146a, 205, 524-5p, 762, 1246, 1260b, 1307, 1826, 3172, 3175, and 3178. Conclusions: 1. Rab25 is a tumor modulator. It can regulate tumor growth and angiogenesis through inhibition of ras in cooperation with RIN1. 2. Our data previous indicated that Rab25 could localize to the nucleus, and it appears to effect the expression of several microRNAs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4161. doi:1538-7445.AM2012-4161