Characterisation of COAS2, a candidate proto-oncogene amplified and over-expressed in human mesenchymal tumours

Abstract

Chromosome One Amplified Sequence 2 (COAS2) is a member of the cyclophilin family of proteins (Meza Zepeda et al., 2002). It has 84% amino acid homology to H. sapiens cyclophilin A, also known as Peptidylprolyl Isomerase A or PPIA. COAS2 is localised in 1q21, and frequently amplified and over-expressed in a specific subset of mesenchymal cancers (sarcomas). We have used the 293 Flp-In system to establish stably transfected cell lines with constitutive and tetracycline-inducible expression of COAS2. The different cell lines have been used for microarray-based expression profiling experiments, as well as various phenotypic analyses, such as growth in soft agar, chemotherapy sensitivity and tumourigenicity in immunodeficient mice. Several expression constructs have been made for production of recombinant protein in bacteria and insect cells. In addition, attempts to localise the protein and confirm putative interaction partners using MYC-His6-and EGFP fusion proteins and confocal fluorescence microscopy were performed.

Through collaboration with Dr. Schiene-Fischer’s group at The Max Planck Institute in Halle, Germany, the enzymatic activity and possible substrate of COAS2 will be evaluated. We are now establishing different Flp-In systems in a set of mesenchymal cell lines to make an improved model system, and we seek to express COAS2 in a yeast cell model system for monoclonal antibody production.