Cbl-b inhibits P-gp transporter function by preventing its translocation into caveolae in multiple drug-resistant gastric and breast cancers

Oncotarget. 2015 Mar 30;6(9):6737-48. doi: 10.18632/oncotarget.3253.

Abstract

The transport function of P-glycoprotein (P-gp) requires its efficient localization to caveolae, a subset of lipid rafts, and disruption of caveolae suppresses P-gp transport function. However, the regulatory molecules involved in the translocation of P-gp into caveolae remain unknown. In the present study, we showed that c-Src dependent Caveolin-1 phosphorylation promoted the translocation of P-gp into caveolae, resulting in multidrug resistance in adriamycin resistant gastric cancer SGC7901/Adr and breast cancer MCF-7/Adr cells. In a negative feedback loop, the translocation of Cbl-b from the nucleus to the cytoplasm prevented the localization of P-gp to caveolae resulting in the reversal of MDR through the ubiquitination and degradation of c-Src. Clinical data showed a significant positive relationship between Cbl-b expression and survival in P-gp positive breast cancer patients who received anthracycline-based chemotherapy. Our findings identified a new regulatory mechanism of P-gp transport function in multiple drug-resistant gastric and breast cancers.

Keywords: Cbl-b; P-gp; caveolae; multiple drug-resistant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B / metabolism
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Adult
  • Animals
  • Antibiotics, Antineoplastic / therapeutic use
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / mortality
  • Breast Neoplasms / pathology
  • Caveolae / drug effects
  • Caveolae / metabolism*
  • Caveolin 1 / genetics
  • Caveolin 1 / metabolism
  • Chemotherapy, Adjuvant
  • Doxorubicin / therapeutic use
  • Drug Resistance, Multiple*
  • Drug Resistance, Neoplasm*
  • Female
  • Humans
  • MCF-7 Cells
  • Male
  • Mice, Nude
  • Phosphorylation
  • Protein Transport
  • Proteolysis
  • Proto-Oncogene Proteins c-cbl / genetics
  • Proto-Oncogene Proteins c-cbl / metabolism*
  • Proto-Oncogene Proteins pp60(c-src) / metabolism
  • RNA Interference
  • Stomach Neoplasms / drug therapy
  • Stomach Neoplasms / genetics
  • Stomach Neoplasms / metabolism*
  • Stomach Neoplasms / pathology
  • Time Factors
  • Transfection
  • Treatment Outcome
  • Ubiquitination
  • Xenograft Model Antitumor Assays

Substances

  • ABCB1 protein, human
  • ATP Binding Cassette Transporter, Subfamily B
  • Adaptor Proteins, Signal Transducing
  • Antibiotics, Antineoplastic
  • CAV1 protein, human
  • Caveolin 1
  • Doxorubicin
  • CBLB protein, human
  • Proto-Oncogene Proteins c-cbl
  • Proto-Oncogene Proteins pp60(c-src)