Low-dose staurosporine selectively reverses BCR-ABL-independent IM resistance through PKC-α-mediated G2/M phase arrest in chronic myeloid leukaemia.

Low-dose staurosporine selectively reverses BCR-ABL-independent IM resistance through PKC-α-mediated G2/M phase arrest in chronic myeloid leukaemia.

Artif Cells Nanomed Biotechnol. 2019 Jan 08;:1-9

Authors: Ma D, Wang P, Fang Q, Yu Z, Zhou Z, He Z, Wei D, Yu K, Lu T, Zhang Y, Wang J

Abstract
Imatinib (IM) resistance has become a critical problem for the treatment of patients with relapsed chronic myeloid leukaemia (CML), so novel therapies are in need. Various isotypes of protein kinases C (PKCs) are up-regulated in CML and related with BCR-ABL regulating several signalling pathways that are crucial to malignant cellular transformation. However, it is still unknown whether PKC isotypes play crucial roles in IM resistance. Therefore, we herein used a PKC pan-inhibitor staurosporine (St). To protect normal cells from damage, a proper dose of St was used, at which IM-resistant CML cells were selectively killed in combination with IM but normal cells survived. The IM resistance of CML cells was best reversed by 4 nM St alone, mainly depending on the G2/M phase arrest. Cell cycle-related proteins p21, CDK2, cyclin A and cyclin B were down-regulated. Meanwhile, PKC-α was more significantly decreased than other PKC isotypes at this concentration. The PKC-α-dependent G2/M phase arrest was induced by down-regulation of CDC23, an important regulator of mitotic progression. Low-dose St also reversed IM resistance in vivo. In conclusion, low-dose St selectively increased the sensitivity of IM-resistant CML to IM by arresting cell cycle in the G2/M phase through PKC-α-dependent CDC23 inhibition.

PMID: 30618318 [PubMed - as supplied by publisher]

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