**3.4. STIM and Orai as pharmacological targets in breast cancer**

Blocking Ca2+ influx with EGTA, Ni2+, or SKF96365 in STIM1 siRNA-, or Orai1 siRNA-treated MDA-MB-231 human breast tumor cells decreased the number of invasive tumor cells [95]. BALB/c mice with 4 T1 tumor cells implanted in the mammary glands were injected with the store-operated channel blocker SKF96365 (10 mg/kg, daily, 20 days treatment), and the lung metastasis was diminished up to 20% [95]. Moreover, intraperitoneal administration of SKF96365 (10 mg/kg, daily, 4 weeks treatment) in NOD/SCID mice with MDA-MB-231 human breast tumor cells determined a significant reduction of lung metastasis after 1 week of treatment, and no metastasis recurrence was observed in 2 weeks after drug withdrawal [95].
