Cr (VI) induces lactate utilization through HIF-1α/MCT1 dependent on p53 protein level

Hexavalent chromium [Cr (VI)] is a known environmental pollutant, which promotes tumorigenesis. Hypoxia-inducible factor-1α (HIF-1α) is crucial for cancer development. Here, we found that Cr (VI) treatment promoted lactate utilization by increasing monocarboxylate transporter 1 (MCT1) and monocarboxylate transporter 4 (MCT4) expression, while increasing the expression of HIF-1α in A549 cells but reducing HIF-1α and MCT1 in HELF cells. CoCl₂, an HIF-1α inducer, increased MCT1, while the HIF-1α inhibitor YC-1 and MCT1 inhibitor AZD3965 suppressed Cr (VI)-induced lactate utilization and cell growth. Chromatin immunoprecipitation (ChIP) assay revealed HIF-1α bound to the MCT1 promoter to enhance its transcription. Using Reactivating p53 and Inducing Tumor Apoptosis (RITA), which can increase the protein level of p53, we discovered that the low level of p53 protein in A549 cells determined the effect of Cr (VI)-induced HIF-1α. These findings highlighted the role of p53 protein level in the effects of Cr (VI) on HIF-1α/MCT1 to induce lactate utilization and cell growth. Targeting the p53/HIF-1α/MCT1 pathway could inhibit Cr (VI)-mediated tumorigenesis.