HIF-1α negatively correlates with BACH2 expression under hypoxia. (A) Immunoblots of CD45⁺ human cells for HIF-1α and BACH2 in subcutaneous tumors, SP, or BM from xenograft mice bearing MCL cells (n = 5, #1-#5). GAPDH was used as a loading control. The normalized values for HIF-1α and BACH2 in each lane are indicated. (B) Linear regression analysis of the relative BACH2 and HIF-1α expression levels based on densitometry analyses of immunoblots shown in panel A. R² values of each xenograft are indicated. (C) MCL cells were cultured under hypoxia (at 1% O₂) at the indicated times. HIF-1α and BACH2 levels were measured by immunoblotting with GAPDH as a loading control. The normalized values for HIF-1α and BACH2 in each lane are indicated. (D) Immunoblots of MCL cells for HIF-1α and BACH2 in the presence or absence of CoCl₂ treatment (200 μmol/L) for 24 h. The BACH2/GAPDH ratios are indicated under each lane. (E) CRISPR-Cas9–mediated HIF-1α^KO MCL cells were generated with mock-transfected cells (HIF-1α^Con) as a control. HIF-1α^KO or HIF-1α^Con cells were incubated in the presence or absence of CoCl₂ for 24 hours. HIF-1α and BACH2 levels were detected by immunoblotting. (F) HIF-1α^KO MCL cells were cultured under hypoxia for 4 hours with HIF-1α^Con cells as a control. HIF-1α and BACH2 levels were detected by immunoblotting.