Decoding Potassium Homeostasis in Cancer Metastasis and Drug Resistance: Insights from a Highly Selective...

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Potassium ions (K+) and K+ channel dysregulation are crucial for cancer cell survival and immune evasion.
• Accurate monitoring of intracellular K+ homeostasis is vital for understanding cancer progression.
• Existing K+ imaging probes lack selectivity, appropriate dynamic range, and broad accessibility.

Purpose of the Study:

• To develop a highly selective and accessible fluorescent sensor for intracellular potassium ion (K+) detection.
• To investigate the role of K+ homeostasis in cancer cell progression and chemoresistance.

Main Methods:

• In vitro selection of a novel RNA-cleaving DNAzyme specific for K+.
• Development of a K+-specific DNAzyme fluorescent sensor with high selectivity (>1000-fold vs. Na+) and a suitable dynamic range (21–200 mM).
• Application of the sensor to monitor intracellular K+ in breast cancer cells and assess the impact of extracellular K+ on chemotherapy efficacy.

Main Results:

• The developed sensor exhibits exceptional selectivity for K+ over other biologically relevant ions.
• Intracellular K+ levels progressively decrease in more advanced breast cancer states.
• Elevated extracellular K+ impairs the efficacy of anticancer drugs (ML133, Amiodarone), and blocking Kir2.1 channels restores sensitivity.

Conclusions:

• K+ homeostasis plays a significant role in tumor progression and chemoresistance.
• The novel K+-specific DNAzyme sensor is a valuable tool for studying ion dynamics in cancer.
• Targeting ion channels presents a promising strategy to overcome chemoresistance in aggressive cancers.