Reference Detail


Missing content? – Request curation!

Request curation for specific Genes, variants, or PubMed publications.

Have questions, comments or suggestions? - Let us know!

Email us at :

Ref Type Journal Article
PMID (27020857)
Authors Herrera-Abreu MT, Palafox M, Asghar U, Rivas MA, Cutts RJ, Garcia-Murillas I, Pearson A, Guzman M, Rodriguez O, Grueso J, Bellet M, Cortés J, Elliott R, Pancholi S, Baselga J, Dowsett M, Martin LA, Turner NC, Serra V
Title Early Adaptation and Acquired Resistance to CDK4/6 Inhibition in Estrogen Receptor-Positive Breast Cancer.
Journal Cancer research
Vol 76
Issue 8
Date 2016 04 15
Abstract Text Small-molecule inhibitors of the CDK4/6 cell-cycle kinases have shown clinical efficacy in estrogen receptor (ER)-positive metastatic breast cancer, although their cytostatic effects are limited by primary and acquired resistance. Here we report that ER-positive breast cancer cells can adapt quickly to CDK4/6 inhibition and evade cytostasis, in part, via noncanonical cyclin D1-CDK2-mediated S-phase entry. This adaptation was prevented by cotreatment with hormone therapies or PI3K inhibitors, which reduced the levels of cyclin D1 (CCND1) and other G1-S cyclins, abolished pRb phosphorylation, and inhibited activation of S-phase transcriptional programs. Combined targeting of both CDK4/6 and PI3K triggered cancer cell apoptosis in vitro and in patient-derived tumor xenograft (PDX) models, resulting in tumor regression and improved disease control. Furthermore, a triple combination of endocrine therapy, CDK4/6, and PI3K inhibition was more effective than paired combinations, provoking rapid tumor regressions in a PDX model. Mechanistic investigations showed that acquired resistance to CDK4/6 inhibition resulted from bypass of cyclin D1-CDK4/6 dependency through selection of CCNE1 amplification or RB1 loss. Notably, although PI3K inhibitors could prevent resistance to CDK4/6 inhibitors, they failed to resensitize cells once resistance had been acquired. However, we found that cells acquiring resistance to CDK4/6 inhibitors due to CCNE1 amplification could be resensitized by targeting CDK2. Overall, our results illustrate convergent mechanisms of early adaptation and acquired resistance to CDK4/6 inhibitors that enable alternate means of S-phase entry, highlighting strategies to prevent the acquisition of therapeutic resistance to these agents. Cancer Res; 76(8); 2301-13. ©2016 AACR.


  • Case insensitive filtering will display rows where any text in any cell matches the filter term
  • Simple literal full or partial string matches
  • Separate multiple filter terms with a spaces, order doesn't matter (a b c and c b a are equivalent )
  • Filtering will only apply to rows that are already loaded on the page, filtering has no impact on query parameters
  • Use quotes to match a longer phrase which contains spaces "mtor c1483f"


  • Generally, the default sort order for tables is set to be first column ascending, however, specific tables may set a different default sort order.
  • Click on any column header arrows to sort by that column
  • Hold down the Shift key and click multiple columns to sort by more than one column, be sure to set ascending or descending order for a given column, before moving on to the next column.

Molecular Profile Treatment Approach
Gene Name Source Synonyms Protein Domains Gene Description Gene Role
Therapy Name Drugs Efficacy Evidence Clinical Trials
Drug Name Trade Name Synonyms Drug Classes Drug Description
Gene Variant Impact Protein Effect Variant Description Associated with drug Resistance
Molecular Profile Indication/Tumor Type Response Type Therapy Name Approval Status Evidence Type Efficacy Evidence References
RB1 loss estrogen-receptor positive breast cancer resistant Palbociclib Preclinical - Cell culture Actionable In a preclinical study, RB1 loss was associated with acquired resistance to Ibrance (palbociclib) in an estrogen-receptor positive breast cancer cell line in culture (PMID: 27020857). 27020857
PIK3CA mutant triple-receptor negative breast cancer sensitive Palbociclib + Pictilisib Preclinical Actionable In a preclinical study, Ibrance (palbociclib) and Pictilisib (GDC-0941) worked synergistically to inhibit the survival of triple-receptor negative breast cancer cell lines harboring PIK3CA mutations in culture (PMID: 27020857). 27020857
PIK3CA wild-type triple-receptor negative breast cancer no benefit Palbociclib + Pictilisib Preclinical Actionable In a preclinical study, the combination of Ibrance (palbociclib) and Pictilisib (GDC-0941) did not improve growth inhibition compared to single drug treatment in PIK3CA wild-type, triple-receptor negative breast cancer cell lines in culture (PMID: 27020857). 27020857
ERBB2 pos PIK3CA act mut Her2-receptor positive breast cancer sensitive Palbociclib + Pictilisib Preclinical Actionable In a preclinical study, Ibrance (palbociclib) and Pictilisib (GDC-0941) worked synergistically to inhibit survival of ERBB2 (HER2)-positive breast cancer cell lines harboring PIK3CA mutations in culture (PMID: 27020857). 27020857