A combination of curcumin with either gramicidin or ouabain selectively kills cells that express the multidrug...

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Multidrug resistance (MDR) in cancer is a major challenge, often mediated by transporters like ABCG2 (breast cancer resistance protein, BCRP).
• Targeting MDR requires novel strategies that selectively eliminate resistant cells without harming normal cells.

Purpose of the Study:

• To introduce a selective killing strategy for multidrug-resistant cells overexpressing ABCG2.
• To investigate the potential of combining specific ATP hydrolysis stimulants for synergistic effects.

Main Methods:

• Utilized subtoxic doses of curcumin to stimulate ABCG2 transporter ATP hydrolysis.
• Combined curcumin with gramicidin A or ouabain to stimulate Na(+),K(+)-ATPase.
• Incubated resistant cells (MCF-7/FLV1) with drug combinations for 72 hours.
• Assessed ATP levels, ABCG2 efflux activity, and induced cell death pathways.

Main Results:

• The drug combination led to overconsumption of ATP, inhibiting ABCG2 efflux and depleting intracellular ATP below the viability threshold.
• Resistant cells expressing ABCG2 were selectively killed, while cells lacking ABCG2 were spared.
• The strategy induced caspase-dependent apoptotic cell death in resistant cells.

Conclusions:

• This novel strategy effectively exploits collateral sensitivity (CS) by combining two compounds that individually do not induce CS.
• The approach offers a potential method for discovering drugs against drug-resistant cancer cells by targeting ABCG2-mediated CS.
• This work expands understanding of ABCG2-mediated collateral sensitivity in cancer therapy.