Regulation of low molecular weight Cyclin E isoform in human colon cancer cells overexpressing Cu/Zn-superoxide dismutase

IBAÑEZ, IRENE L.; BRACALENTE, CANDELARIA; NOTCOVICH, CINTIA; POLICASTRO, LUCÍA; DURÁN, HEBE

San Pablo

Congreso; Free Radicals Brazil 2011- VII Meeting of the SFRBM-South American Group; 2011

SFRBM-South American Group

Cyclin E regulates G1/S transition. Its full length form (FL) can be modified by proteolytic cleavage resulting in low molecular weight (LMW)-isoforms. These isoforms were associated with poor prognosis in different types of cancer. This could be related to the hyperactivity of these isoforms, which induces cell cycle progression and can favor genomic instability conferring cells a more malignant phenotype. Cell cycle progression is modulated by variations in cyclin-CDK complexes and reactive oxygen species (ROS) levels. The exposure to moderate levels of ROS increase cell growth, whereas high levels may induce adaptation, apoptosis, differentiation or cytotoxicity. We evaluated the effects of Cu/Zn-dependent superoxide dismutase (Cu/Zn-SOD) overexpression on cyclin E regulation in human colorectal carcinoma LoVo cells. Two clones (B4 and F10) stably transfected with the cDNA of human Cu/Zn-SOD with different behavior were obtained. Both clones were compared to control cells (non-transfected or transfected with the empty vector). The levels of LMW-isoform cyclin E (p