miR-139 acts as a tumor suppressor in T-cell acute lymphoblastic leukemia by targeting CX chemokine receptor 4.

MicroRNAs (miRNAs) act as tumor regulators in T-cell acute lymphoblastic leukemia (T-ALL). However, the molecular mechanisms by which miRNA-139 (miR-139) regulates T-ALL remain unclear. In this study, we found that miR-139 was lowly expressed whereas C-X-C chemokine receptor type 4 (CXCR4) was highly expressed in T-ALL cell lines and patient samples. The T-ALL patients simultaneously with high levels of CXCR4 and low expression of miR-139 possessed poor prognosis. Moreover, the introduction of miR-139 inhibited T-ALL cell proliferation and invasion in vitro and suppressed tumor growth and lung metastasis in vivo. CXCR4 was identified as a direct target of miR-139. The suppressive effects of miR-139 were mimicked and counteracted by CXCR4 depletion and overexpression, respectively. Overall, the miR-139/CXCR4 axis plays an important role in T-ALL carcinogenesis.