Store-operated Ca(2+) entry in rhabdomyosarcoma cells

Area of Science:

• Oncology
• Molecular Biology
• Cell Physiology

Background:

• Rhabdomyosarcoma (RMS) exhibits resistance to therapy, with key molecular drivers of its aggressive behavior incompletely understood.
• Cell migration and proliferation in RMS correlate with intracellular calcium levels.
• Store-operated calcium entry (SOCE) regulates intracellular calcium, involving Orai1 channels and NFκB transcription factors.

Purpose of the Study:

• To investigate the expression and role of Orai1, STIM1, and NFκB in human rhabdomyosarcoma cell lines.
• To determine the impact of Orai1 signaling on rhabdomyosarcoma cell proliferation and migration.

Main Methods:

• Analysis of Orai1, STIM1, and NFκB expression in RD and RH30 cell lines using RT-PCR and Western blot.
• Measurement of intracellular calcium ([Ca(2+)]i) and SOCE using Fura-2 fluorescence and thapsigargin.
• Assessment of cell migration (transwell assay) and proliferation (clonogenic assay) with and without SOCE inhibitors (BTP2, 2-APB) and an NFκB inhibitor (wogonin).

Main Results:

• Orai1, STIM1, and NFκB were expressed in both embryonal (RD) and alveolar (RH30) rhabdomyosarcoma cell lines.
• SOCE was significantly inhibited by BTP2, 2-APB, and wogonin.
• Inhibitors of SOCE (2-APB, BTP2) and NFκB (wogonin) markedly reduced rhabdomyosarcoma cell migration and proliferation.

Conclusions:

• Orai1-mediated SOCE is present in rhabdomyosarcoma cells.
• Orai1 signaling plays a crucial role in driving rhabdomyosarcoma cell migration, invasion, and proliferation.
• Targeting Orai1 or NFκB may offer novel therapeutic strategies for rhabdomyosarcoma.