Functional consequences of enhanced expression of STIM1 and Orai1 in Huh-7 hepatocellular carcinoma tumor-initiating cells.

STIM1 overexpression may facilitate cancer cell survival by increasing ER Ca2+-buffering capacity, which makes more Ca2+ available for the cytosolic events, on the other hand, possibly preventing Ca2+-dependent enzymatic activity in mitochondria whose Ca2+ uniporter requires much higher cytosolic Ca2+ levels.