Acquired resistance to combined BET and CDK4/6 inhibition in triple-negative breast cancer

Nat Commun. 2020 May 11;11(1):2350. doi: 10.1038/s41467-020-16170-3.

Abstract

BET inhibitors are promising therapeutic agents for the treatment of triple-negative breast cancer (TNBC), but the rapid emergence of resistance necessitates investigation of combination therapies and their effects on tumor evolution. Here, we show that palbociclib, a CDK4/6 inhibitor, and paclitaxel, a microtubule inhibitor, synergize with the BET inhibitor JQ1 in TNBC lines. High-complexity DNA barcoding and mathematical modeling indicate a high rate of de novo acquired resistance to these drugs relative to pre-existing resistance. We demonstrate that the combination of JQ1 and palbociclib induces cell division errors, which can increase the chance of developing aneuploidy. Characterizing acquired resistance to combination treatment at a single cell level shows heterogeneous mechanisms including activation of G1-S and senescence pathways. Our results establish a rationale for further investigation of combined BET and CDK4/6 inhibition in TNBC and suggest novel mechanisms of action for these drugs and new vulnerabilities in cells after emergence of resistance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Azepines / pharmacology
  • Cell Cycle Checkpoints / drug effects
  • Cell Proliferation / drug effects
  • Clone Cells
  • Cyclin-Dependent Kinase 4 / antagonists & inhibitors*
  • Cyclin-Dependent Kinase 4 / metabolism
  • Cyclin-Dependent Kinase 6 / antagonists & inhibitors*
  • Cyclin-Dependent Kinase 6 / metabolism
  • DNA, Neoplasm / metabolism
  • Drug Resistance, Neoplasm* / drug effects
  • Drug Synergism
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Mice
  • Models, Biological
  • Mutation / genetics
  • Paclitaxel / pharmacology
  • Piperazines / pharmacology
  • Ploidies
  • Proteins / antagonists & inhibitors*
  • Proteins / metabolism
  • Pyridines / pharmacology
  • Retinoblastoma Protein / genetics
  • Retinoblastoma Protein / metabolism
  • Treatment Outcome
  • Triazoles / pharmacology
  • Triple Negative Breast Neoplasms / drug therapy*
  • Triple Negative Breast Neoplasms / genetics
  • Up-Regulation / drug effects
  • Up-Regulation / genetics

Substances

  • (+)-JQ1 compound
  • Azepines
  • DNA, Neoplasm
  • Piperazines
  • Proteins
  • Pyridines
  • Retinoblastoma Protein
  • Triazoles
  • bromodomain and extra-terminal domain protein, human
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinase 6
  • palbociclib
  • Paclitaxel