Comparative transcription profiling upon FBLN5 overexpression in transformed COS-7 and normal CV-1 cells

A novel class of genes has recently been identified as anticancer genes, which upon ectopic overexpression selectively destroy the transformed tumour cells, while leaving the untransformed normal cells unharmed. Examples include TRAIL, PAR4 and Orctl3. We have isolated 16 novel anticancer genes of human origin through a gain of function, forward genetic screen in mammalian cells. Among these, FBLN5 was chosen for further investigation. FBLN5 is a secreted ECM glycoprotein the physiological functions of which remain largely elusive, however it is downregulated in numerous malignancies and Fibln5-/- mice exhibited elastic fibre abnormalities including cutis laxa. When transfected in the normal CV-1 cells and their SV-40 transformed counterpart COS-7 cells, FBLN5 caused extensive cell death in latter and not in the former. In order to investigate such differential effects of FBLN5, we performed transcriptional profiling of COS-7 and CV-1 cells upon FBLN5 transfection where wild type COS-7 and CV-1 cells were used as controls. We conducted exon-level expression profiles of > 540,000 transcripts including coding mRNA, long non-coding RNA, microRNA, novel transcripts and also the alternative splice variants. Briefly, FBLN5 caused downregulation of MYC regulated genes in COS-7 cells while opposite was observed in CV-1 cells. Also, FBLN5 caused upregulation of cell death related genes in COS-7 cells but not in CV-1 cells.