CALCRL induces resistance to daunorubicin in acute myeloid leukemia cells through upregulation of XRCC5/TYK2/JAK1 pathway.

Chemotherapy is the main treatment option for acute myeloid leukemia (AML), but acquired resistance of leukemic cells to chemotherapeutic agents often leads to difficulties in AML treatment and disease relapse. High calcitonin receptor-like (CALCRL) expression is closely associated with poorer prognosis in AML patients. Therefore, this study was performed by performing CALCRL overexpression constructs in AML cell lines HL-60 and Molm-13 with low CALCRL expression. The results showed that overexpression of CALCRL in HL-60 and Molm-13 could confer resistance properties to AML cells and reduce the DNA damage and cell cycle G0/G1 phase blocking effects caused by daunorubicin (DNR) and others. Overexpression of CALCRL also reduced DNR-induced apoptosis. Mechanistically, the Cancer Clinical Research Database analyzed a significant positive correlation between XRCC5 and CALCRL in AML patients. Therefore, the combination of RT-PCR and Western blot studies further confirmed that the expression levels of XRCC5 and PDK1 genes and proteins were significantly upregulated after overexpression of CALCRL. In contrast, the phosphorylation levels of AKT/PKCε protein, a downstream pathway of XRCC5/PDK1, were significantly upregulated. In the response study, transfection of overexpressed CALCRL cells with XRCC5 siRNA significantly upregulated the drug sensitivity of AML to DNR. The expression levels of PDK1 protein and AKT/PKCε phosphorylated protein in the downstream pathway were inhibited considerably, and the expression of apoptosis-related proteins Bax and cleaved caspase-3 were upregulated. Animal experiments showed that the inhibitory effect of DNR on the growth of HL-60 cells and the number of bone marrow invasions were significantly reversed after overexpression of CALCRL in nude mice. However, infection of XCRR5 shRNA lentivirus in HL-60 cells with CALCRL overexpression attenuated the effect of CALCRL overexpression and upregulated the expression of apoptosis-related proteins induced by DNR. This study provides a preliminary explanation for the relationship between high CALCRL expression and poor prognosis of chemotherapy in AML patients. It offers a more experimental basis for DNR combined with molecular targets for precise treatment in subsequent studies.