Overexpression of carbonyl reductase 1 in ovarian cancer cells suppresses proliferation and activates the eIF2 signaling pathway.

Abstract

High expression of carbonyl reductase 1 (CBR1) protein in ovarian cancer cells inhibits tumor growth and metastasis. However, the underlying mechanism is unknown. To investigate the mechanism by which CBR1 suppresses tumor growth, the present study generated ovarian cancer cells that constitutively overexpress human CBR1 (hCBR1) protein. Ovarian cancer cell lines (OVCAR-3 and SK-OV-3) were transfected with a plasmid encoding hCBR1, followed by selection with G418 to isolate hCBR1-overexpressing lines. The proliferation rates of hCBR1-overexpressing cells were then compared with those of negative control and wild-type cells. Overexpression of hCBR1 led to significant inhibition of proliferation (P<0.05). Subsequently, to investigate changes in intracellular signaling pathways, cellular proteins were extracted and subjected to proteome analysis using liquid chromatography followed by mass spectrometry. There was an inverse correlation between CBR1 protein expression and cell proliferation. In addition, Ingenuity Pathway Analysis of hCBR1-overexpressing cell lines was performed, which revealed changes in the expression of proteins involved in signaling pathways related to growth regulation. Of these, the eukaryotic translation initiation factor 2 (eIF2) signaling pathway was upregulated most prominently. Thus, alterations in multiple tumor-related signaling pathways, including eIF2 signaling, may lead to growth suppression. Taken together, the present data may lead to the development of new drugs that target CBR1 and related signaling pathways, thereby improving outcomes for patients with ovarian cancer.