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.
ABSTRACT
BACKGROUND: Carbonyl reductase 1 (CBR1) is a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductase with broad substrate specificity. CBR1 catalyzes the reduction of numerous carbonyl compounds, including quinones, prostaglandins, menadione, and multiple xenobiotics, while also participating in various cellular processes, such as carcinogenesis, apoptosis, signal transduction, and drug resistance. In this study, we aimed to generate transgenic mice overexpressing mouse Cbr1 (mCbr1), characterize the mCbr1 expression in different organs, and identify changes in protein expression patterns. METHODS AND RESULTS: To facilitate a deeper understanding of the functions of CBR1, we generated transgenic mice overexpressing CBR1 throughout the body. These transgenic mice overexpress 3xFLAG-tagged mCbr1 (3xFLAG-mCbr1) under the CAG promoter. Two lines of transgenic mice were generated, one with 3xFLAG-mCbr1 expression in multiple tissues, and the other, with specific expression of 3xFLAG-mCbr1 in the heart. Pathway and network analysis using transgenic mouse hearts identified 73 proteins with levels of expression correlating with mCbr1 overexpression. The expression of voltage-gated anion channels, which may be directly related to calcium ion-related myocardial contraction, was also upregulated. CONCLUSION: mCbr1 transgenic mice may be useful for further in vivo analyses of the molecular mechanisms regulated by Cbr1; such analyses will provide a better understanding of its effects on carcinogenesis and cardiotoxicity of certain cancer drugs.
