[HTML][HTML] Pre-treatment with the CDK4/6 inhibitor palbociclib improves the efficacy of paclitaxel in TNBC cells

D Cretella, C Fumarola, M Bonelli, R Alfieri… - Scientific reports, 2019 - nature.com
D Cretella, C Fumarola, M Bonelli, R Alfieri, S La Monica, G Digiacomo, A Cavazzoni…
Scientific reports, 2019nature.com
Abstract Triple Negative Breast Cancer (TNBC) is a challenging disease due to the lack of
druggable targets; therefore, chemotherapy remains the standard of care and the
identification of new targets is a high clinical priority. Alterations in the components of the cell
cycle machinery have been frequently reported in cancer; given the success obtained with
the CDK4/6 inhibitor palbocicib in ER-positive BC, we explored the potential of combining
this drug with chemotherapy in Rb-positive TNBC cell models. The simultaneous …
Abstract
Triple Negative Breast Cancer (TNBC) is a challenging disease due to the lack of druggable targets; therefore, chemotherapy remains the standard of care and the identification of new targets is a high clinical priority. Alterations in the components of the cell cycle machinery have been frequently reported in cancer; given the success obtained with the CDK4/6 inhibitor palbocicib in ER-positive BC, we explored the potential of combining this drug with chemotherapy in Rb-positive TNBC cell models. The simultaneous combination of palbociclib with paclitaxel exerted an antagonistic effect; by contrast, the sequential treatment inhibited cell proliferation and increased cell death more efficaciously than single treatments. By down-regulating the E2F target c-myc, palbociclib reduced HIF-1α and GLUT-1 expression, and hence glucose uptake and consumption both under normoxic and hypoxic conditions. Importantly, these inhibitory effects on glucose metabolism were enhanced by palbociclib/paclitaxel sequential combination; the superior efficacy of such combination was ascribed to the ability of paclitaxel to inhibit palbociclib-mediated induction of AKT and to further down-regulate the Rb/E2F/c-myc signaling. Our results suggest that the efficacy of standard chemotherapy can be significantly improved by a pre-treatment with palbociclib, thus offering a better therapeutic option for Rb-proficient TNBC.
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