Activation of chloride current and decrease of cell volume by ATP in nasopharyngeal carcinoma cells

Area of Science:

• Cell Biology
• Molecular Physiology
• Oncology

Background:

• Nasopharyngeal carcinoma (NPC) is a malignancy with complex cellular behaviors.
• Cell volume regulation is crucial for cellular function and can be altered in cancer.
• Adenosine triphosphate (ATP) is increasingly recognized for its signaling roles beyond energy metabolism.

Purpose of the Study:

• To investigate the effect of extracellular ATP on chloride currents in NPC cells.
• To determine the role of ATP-induced chloride currents in NPC cell volume regulation.
• To identify the purinergic receptor involved in ATP signaling in NPC.

Main Methods:

• Whole-cell patch clamp electrophysiology was employed to measure ionic currents.
• Cell volume was assessed using dedicated measurement techniques.
• Pharmacological agents, including chloride channel blockers and purinoceptor antagonists, were utilized.

Main Results:

• Micromolar concentrations of extracellular ATP activated a dose-dependent chloride current with outward rectification.
• The ATP-activated current reversed near the chloride equilibrium potential and was sensitive to chloride concentration.
• The chloride channel blocker NPPB and the P2Y antagonist reactive blue 2 significantly inhibited the current.
• ATP induced a decrease in cell volume under isotonic conditions, an effect dependent on extracellular and intracellular chloride.
• These findings implicate P2Y purinoceptors in mediating ATP's effects on chloride currents and cell volume.

Conclusions:

• Extracellular ATP at micromolar concentrations activates a chloride current in nasopharyngeal carcinoma cells.
• This ATP-induced chloride current is involved in the regulation of cell volume.
• The activation of the chloride current and subsequent cell volume changes are mediated by the P2Y purinoceptor.