BHLHE41 Overexpression Alleviates the Malignant Behavior of Colon Cancer Cells Induced by Hypoxia via Modulating HIF-1α/EMT Pathway.

BHLHE41 has been shown to be a marker of tumorigenesis. Colon cancer (CC) is a common malignant tumor of colonic mucosa. This study mainly explored the mechanism of BHLHE41 in alleviating malignant behavior of hypoxia-induced CC cells. The levels of BHLHE41 in CC and normal cell lines were tested by Western blot and qRT-PCR. After, CC cells were subjected to hypoxia treatment and BHLHE41 overexpression transfection, and the BHLHE41 expression, the effect of BHLHE41 on CC cell viability, apoptosis, migration, and invasion and cell cycle were tested by qRT-PCR and relevant cell functional experiments. HIF-1α and epithelial-mesenchymal transition- (EMT-) related proteins were tested by Western blot. Moreover, CC tumor-bearing model was established in nude mice, and the effect of BHLHE41 on the tumor was evaluated by measuring the tumor volume and weight. Then, the expressions of BHLHE41 and EMT-related proteins were detected by immunohistochemistry and Western blot. Western blot and qRT-PCR showed that BHLHE41 was lowly expressed in CC cells. BHLHE41 overexpression could inhibit the hypoxia-induced CC cell viability, migration, and invasion, induce apoptosis, and alter cell cycle. Besides, BHLHE41 overexpression could enhance the levels of E-cadherin but reduce the levels of HIF-1α, N-cadherin, vimentin, and MMP9 in hypoxia-induced CC cells. Moreover, BHLHE41 overexpression reduced tumor volume, weight, and EMT-related proteins levels in tumor tissues. BHLHE41 overexpression could mitigate the malignant behavior of hypoxia-induced CC via modulating the HIF-1α/EMT pathway.