Poster Presentation 28th Lorne Cancer Conference 2016

Exploration of novel regulators of mutant p53 (#266)

Reshma Vijayakumaran 1 , Kah Hin Tan , Franco Caramia , Piyush Madhamshettiwar 2 , Kaylene Simpson 2 3 , Sue Haupt 1 , Ygal Haupt 1 3 4
  1. Tumour suppression laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
  2. Victorian Centre for Functional Genomics, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
  3. Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia
  4. Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia

Mutations in the tumour suppressor gene, TP53 occur in more than 50% of all cancers. Most of these mutant proteins not only lose their ability to limit cell growth, but they also gain oncogenic functions broadly referred to as gain of function (GOF). Cancer cells frequently accumulate this mutant protein and a subset of these cancer cells are addicted to it for survival. In cancers, expression levels of mutant p53 in cancer cells is constitutively high in contrast to the stress regulated wt p53 levels in normal cells. This highlights the differences in regulation of mutant and wt p53. In order to identify the major players in the regulation of mutant p53, a high-throughput siRNA screen of protein coding genes was performed in our lab. Around 18,120 genes were evaluated for their effect on mutant p53 levels, through a series of primary, secondary and tertiary screens in two different mutant p53 expressing cell lines. We selected 170 genes from the tertiary screen for subsequent analysis. By considering select parameters (including fold change and cell viability, in addition to extensive knowledge mining and usage of tools for network and pathway analysis), we selected 37 genes for validation through immunoblotting and qRT-PCR. Strategic experiments are planned to unravel the mechanisms of their regulation of p53. The overall aim is to identify key target mutant p53 regulators with therapeutic potential.