Aberrantly reduced expression of miR-342-5p contributes to CCND1-associated chronic myeloid leukemia progression and imatinib resistance.

Chronic myeloid leukemia (CML) is a myeloproliferative disorder associated with the Philadelphia chromosome, and the current standard of care is the use of tyrosine kinase inhibitors (TKI). However, some patients will not achieve a molecular response and may progress to blast crisis, and the underlying mechanisms remain to be clarified. In this study, next-generation sequencing was used to explore endogenous miRNAs in CML patients versus healthy volunteers, and miR-342-5p was identified as the primary target. We found that miR-342-5p was downregulated in CML patients and had a significant inhibitory effect on cell proliferation in CML. Through a luciferase reporter system, miR-342-5p was reported to target the 3'-UTR domain of CCND1 and downregulated its expression. Furthermore, overexpression of miR-342-5p enhanced imatinib-induced DNA double-strand breaks and apoptosis. Finally, by analyzing clinical databases, we further confirmed that miR-342-5p was associated with predicted molecular responses in CML patients. In conclusion, we found that both in vivo and in vitro experiments and database cohorts showed that miR-342-5p plays a key role in CML patients, indicating that miR-342-5p may be a potential target for future CML treatment or prognostic evaluation.