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Gibberellin derivative GA-13315 sensitizes multidrug-resistant cancer cells by antagonizing ABCB1 while agonizes

Jiao Mo1, Min Kang1, Jun-Xian Ye1

  • 1School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Chun Rong West Street No. 1168, Chenggong, Kunming, 650500, China.

Cancer Chemotherapy and Pharmacology
|May 11, 2016
PubMed
Abstract

Insights

GA-13315, a gibberellin derivative, overcomes multidrug resistance by inhibiting ABCB1 transporter function. It also upregulates Bax, potentially enhancing its antitumor effects in resistant cancer cells.

Area of Science:

  • Pharmacology
  • Molecular Biology
  • Cancer Research

Background:

  • Multidrug resistance (MDR) is a major challenge in cancer chemotherapy.
  • ATP-binding cassette (ABC) transporters, such as P-glycoprotein (ABCB1) and multidrug resistance-associated protein 1 (ABCC1), are key mediators of MDR.
  • Novel agents that can overcome MDR are urgently needed.

Purpose of the Study:

  • To investigate the chemosensitizing effects of GA-13315 in multidrug-resistant cancer cell lines.
  • To elucidate the underlying mechanisms of GA-13315's action, particularly its interaction with ABC transporters.
  • To evaluate the potential of GA-13315 as a chemosensitizer in combination therapy.

Main Methods:

  • Cytotoxicity and chemosensitization were assessed using MTT assays.
  • ABC transporter function was evaluated by measuring intracellular drug accumulation (doxorubicin, rhodamine 123) and ATPase activity.
  • Expression of apoptosis regulators (e.g., Bax) was analyzed via quantitative PCR and Western blot.

Main Results:

  • GA-13315 selectively killed MCF-7/adr cells overexpressing ABCB1.
  • It reversed ABCB1-mediated resistance but exacerbated ABCC1-mediated resistance.
  • GA-13315 increased intracellular drug accumulation in ABCB1-overexpressing cells and inhibited ABCB1 ATPase activity.
  • GA-13315 upregulated the pro-apoptotic protein Bax in MCF-7/adr cells.

Conclusions:

  • GA-13315 sensitizes multidrug-resistant cells, primarily by inhibiting ABCB1 efflux function.
  • Upregulation of Bax may contribute to GA-13315's sensitizing effects.
  • The differential effects of GA-13315 on various ABC transporters warrant further investigation for optimizing cancer therapy.
Keywords:
ABC transporterABCB1ABCC1ChemosensitizationMultidrug resistance

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