Over-expression of Orai1 mediates cell proliferation and associates with poor prognosis in human non-small cell lung carcinoma.

Orai1 and STIM1 mediate calcium release-activated calcium current (CRAC) which is the best characterized store-operated calcium current involving in a wide range of cell progresses, such as cell proliferation, metastasis, apoptosis. Orai1 has been studied as a carcinogenic biomarker in some cancers such as esophageal cancer. However, its function and clinical significance in non-small cell lung cancer (NSCLC) have not been well studied. The present study was aimed at discussing the relationship between Orai1 and lung cancer malignant behavior with its clinical significance. We used quantitative real-time-PCR and Western blot to detect the expression of Orai1 in NSCLC cell lines and fresh cancer tissues. Immunohistochemistry were performed to test the location and expression of Orai1 in paraffin sections. We found that Orai1 was markedly overexpressed in both NSCLC cell lines and fresh cancer tissues. Immunohistochemistry data also revealed that overexpression of Orai1 was present in 42.4% of NSCLC tissues, compared with the corresponding adjacent nontumorous tissues. Furthermore, NSCLC patients with high Orai1 expression survived shorter than those with low Orai1 expression. In addition, when knockdown Orai1 by RNAi technic, we found the PI3k/AKT/ERK pathway was inhibited which may indicated that Orai1 could influence cell proliferation. Taken together, our study demonstrated that Orai1 was remarkably overexpressed in NSCLC and could be served as a potential prognostic marker for patients with this deadly disease.