Poster abstracts

Poster number 29 submitted by Gayani Dedduwa-Mudalige

Kinetic and adduct characterization of cisplatin-RNA interactions

Gayani N P Dedduwa-Mudalige (Wayne State University, Department of Chemistry, Detroit, MI 48202, USA ), Sofi K C Elmroth (Lund University, Department of Biochemistry and Structural Biology, Sweden), Christine S Chow (Wayne State University, Department of Chemistry, Detroit, MI 48202, USA)

Abstract:
Cisplatin, or cis-diamminedichlorido platinum (II), is a metal-based anticancer drug widely used to treat different carcinomas. The antitumor activity of cisplatin is believed to be derived from its interactions with DNA, which influences downstream biological functions such as transcription and translation. Besides DNA coordination, cisplatin has been shown to interact with proteins, small sulfur-containing molecules, and RNA. Among different types of RNA inside a cell, ribosomal RNA plays a vital role in protein synthesis. The current work focused on investigating the interactions of ribosomal RNA and cisplatin. Two functionally important RNAs, helix 69 in the large ribosomal subunit and 790 loop in the small subunit, were selected as regions of interest. As an initial approach, small representative RNA constructs were designed for cisplatin reactions. Rates of platination of these constructs were determined by gel analysis. Salt dependence in cisplatin reactivity was observed, consistent with previously published work. Interestingly, naturally occurring nucleotide modifications were found to influence cisplatin reactivity without significant effects on electrostatics. Characterization of the platination sites was done with MALDI mass spectrometry and chemical probing. Consecutive Gs present in the RNA constructs were found to be the primary platination sites. These findings provide interesting insights into metal-RNA interactions found at biologically important regions of ribosomal RNA, which could be valuable targets for future drug design.

Keywords: cisplatin, ribosome , kinetics