[HTML][HTML] MCL-1 inhibition provides a new way to suppress breast cancer metastasis and increase sensitivity to dasatinib

AIJ Young, AMK Law, L Castillo, S Chong… - Breast Cancer …, 2016 - Springer
AIJ Young, AMK Law, L Castillo, S Chong, HD Cullen, M Koehler, S Herzog, T Brummer…
Breast Cancer Research, 2016Springer
Background Metastatic disease is largely resistant to therapy and accounts for almost all
cancer deaths. Myeloid cell leukemia-1 (MCL-1) is an important regulator of cell survival and
chemo-resistance in a wide range of malignancies, and thus its inhibition may prove to be
therapeutically useful. Methods To examine whether targeting MCL-1 may provide an
effective treatment for breast cancer, we constructed inducible models of BIMs2A expression
(a specific MCL-1 inhibitor) in MDA-MB-468 (MDA-MB-468-2A) and MDA-MB-231 (MDA-MB …
Background
Metastatic disease is largely resistant to therapy and accounts for almost all cancer deaths. Myeloid cell leukemia-1 (MCL-1) is an important regulator of cell survival and chemo-resistance in a wide range of malignancies, and thus its inhibition may prove to be therapeutically useful.
Methods
To examine whether targeting MCL-1 may provide an effective treatment for breast cancer, we constructed inducible models of BIMs2A expression (a specific MCL-1 inhibitor) in MDA-MB-468 (MDA-MB-468-2A) and MDA-MB-231 (MDA-MB-231-2A) cells.
Results
MCL-1 inhibition caused apoptosis of basal-like MDA-MB-468-2A cells grown as monolayers, and sensitized them to the BCL-2/BCL-XL inhibitor ABT-263, demonstrating that MCL-1 regulated cell survival. In MDA-MB-231-2A cells, grown in an organotypic model, induction of BIMs2A produced an almost complete suppression of invasion. Apoptosis was induced in such a small proportion of these cells that it could not account for the large decrease in invasion, suggesting that MCL-1 was operating via a previously undetected mechanism. MCL-1 antagonism also suppressed local invasion and distant metastasis to the lung in mouse mammary intraductal xenografts. Kinomic profiling revealed that MCL-1 antagonism modulated Src family kinases and their targets, which suggested that MCL-1 might act as an upstream modulator of invasion via this pathway. Inhibition of MCL-1 in combination with dasatinib suppressed invasion in 3D models of invasion and inhibited the establishment of tumors in vivo.
Conclusion
These data provide the first evidence that MCL-1 drives breast cancer cell invasion and suggests that MCL-1 antagonists could be used alone or in combination with drugs targeting Src kinases such as dasatinib to suppress metastasis.
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