CD-200 induces apoptosis and inhibits Bcr-Abl signaling in imatinib-resistant chronic myeloid leukemia with T315I mutation

Isoalantolactone mediates the degradation of BCR-ABL protein in imatinib-resistant CML cells by down-regulating survivin

Isoalantolactone (Iso) is a bioactive lactone isolated from the root of Inula helenium L, which has been reported to have many pharmacological effects. To investigate the role and mechanism of isoalantolactone in chronic myeloid leukemia (CML), we first investigated isoalantolactone's anti-proliferative effects on imatinib-sensitive and imatinib-resistant CML cells by CCK8. Flow cytometry was used to detect isoalantolactone-induced cell apoptosis. Survivin was overexpressed in KBM5 and KBM5T315I cells using the lentivirus vector pSIN-3×flag-PURO. In KBM5 and KBM5T315I cells, shRNA was used to knockdown survivin. Cellular Thermal Shift Assay (CETSA) was used to detect the interaction between isoalantolactone and survivin. The ubiquitin of survivin induced by isoalantolactone was detected through immunoprecipitation. Quantitative polymerase-chain reaction (Q-PCR) and western blotting were used to detect the levels of mRNA and protein. Isoalantolactone inhibits the proliferation and promotes apoptosis of imatinib-resistant CML cells. Although isoalantolactone inhibits the proteins of BCR-ABL and survivin, it cannot inhibit survivin and BCR-ABL mRNA levels. Simultaneously, it was shown that isoalantolactone can degrade survivin protein by increasing ubiquitination. It was demonstrated that isoalantolactone-induced survivin mediated downregulation of BCR-ABL protein. It was also revealed that isoalantolactone triggered BCR-ABL protein degradation via caspase-3. Altogether, isoalantolactone inhibits survivin through the ubiquitin proteasome pathway, and mediates BCR-ABL downregulation in a caspase-3 dependent manner. These data suggest that isoalantolactone is a natural compound, which can be used as a potential drug to treat TKI-resistant CML.

Unraveling survivin expression in chronic myeloid leukemia: Molecular interactions and clinical implications

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the BCR-ABL oncoprotein, known to drive leukemogenesis by orchestrating multiple signaling pathways ultimately involved in cell survival. Despite successful response rates of CML patients to tyrosine kinase inhibitors (TKIs), resistance eventually arises due to BCR-ABL-dependent and independent mechanisms. Survivin is an inhibitor of apoptosis protein acting in the interface between apoptosis deregulation and cell cycle progression. In CML, high levels of survivin have been associated with late stages of disease and therapy resistance. In this review, we provide an overview of important aspects concerning survivin subcellular localization and expression pattern in CML patients and cell lines. Moreover, we highlight the relevance of molecular networks involving survivin for disease progression and treatment resistance. Finally, we discuss the mechanisms accounting for survivin overexpression, as well as novel therapeutic interventions that have been designed to counteract survivin-associated malignancy in CML.