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

Sci Rep. 2019 Sep 10;9(1):13014. doi: 10.1038/s41598-019-49484-4.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Apoptosis
  • Cell Proliferation
  • Cyclin-Dependent Kinase 4 / antagonists & inhibitors*
  • Cyclin-Dependent Kinase 6 / antagonists & inhibitors*
  • Drug Synergism*
  • Female
  • Humans
  • Paclitaxel / administration & dosage
  • Piperazines / administration & dosage
  • Pyridines / administration & dosage
  • Triple Negative Breast Neoplasms / drug therapy*
  • Tumor Cells, Cultured

Substances

  • Piperazines
  • Pyridines
  • CDK4 protein, human
  • CDK6 protein, human
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinase 6
  • palbociclib
  • Paclitaxel