Biliverdin Reductase A (BLVRA) Promotes Colorectal Cancer Cell Progression by Activating the Wnt/β-Catenin Signaling Pathway

Purpose: Biliverdin reductase A (BLVRA) is a pleiotropic enzyme that converts biliverdin-IX-alpha into the antioxidant and anti-nitrosative compound, bilirubin-IX-alpha. It is related to various diseases, including cancer. It is overexpressed in many types of cancers and promotes cancer development and metastasis, but the effects of BLVRA in colorectal cancer have not been researched at present. This study was aimed to investigate the effects of biliverdin reductase A (BLVRA) in vivo and vitro experiments and its possible mechanism. Methods: The clinical samples of CRC patients and CRC cell lines HT-29 and SW620 were chosen to perform the experiments. ELISA and Immunohistochemistry (IHC) were applied to test the level of BLVRA in patients. HT-29 knockdown of BLVRA and SW620 overexpression of BLVRA was established by the lentiviral vector transfection. Reverse transcription-quantitative real-time polymerase chain reaction and Western blotting were performed to examine the expression of BLVRA. MTT was used to detect the proliferation of CRC cells. Flow cytometry was applied to assess the rate of apoptosis. Transwell assay was performed to examine the capacity of migration and invasion. Immunofluorescence staining was adopted to assess the expression of E-cadherin and vimentin. Western blotting was utilized to detect the expression of apoptosis-related proteins, EMT-related proteins and target proteins of Wnt/beta-catenin signaling pathway. Results: Analysis of the clinical samples revealed that BLVRA was overexpressed in CRC patients and implied poor prognosis. BLVRA overexpression in the in vitro studies revealed that it increased the potential of CRC cells for proliferation, migration and invasion; augmented EMT; and hindered apoptosis. In addition, BLVRA overexpression was found to upregulate positive target genes and downregulate negative target genes of the Wnt/beta-catenin signaling pathway, which implied that the biological effects of BLVRA in CRC were mediated by this pathway. In contrast, knockdown of BLVRA manifested the opposite effects. Conclusion: Our results suggested that BLVRA might be a promising prognostic marker and a potential therapeutic target in CRC.