Disruption of Calcium Channels Blocks Breast Cancer Metastasis

Cancer researchers have found that they could stop the spread of breast cancer cells in culture and in animal models by inhibiting the expression of two genes, Orai1 and STIM1.

The two membrane proteins, STIM1 (stromal interaction molecule 1) and Orai1 that are produced by these genes have each been shown to be essential for the function of store-operated calcium channels (SOCCs). Yet, how these proteins functionally interact is not known.

Since calcium transport is critically related to cell motility, investigators from Weill Cornell Medical College (New York, NY, USA) designed a series of experiments to study the importance of these calcium channel proteins in breast cancer cells. To this end, they used RNA interference techniques to block the expression of the two genes in cells isolated from metastatic breast cancer tumors.

The researchers reported in the February 2, 2009, issue of the journal Cancer Cell that reduction of Orai1 or STIM1 by RNA interference or treatment with a pharmacologic inhibitor of store-operated calcium channels decreased tumor metastasis in animal models.

Preliminary data showed that within metastatic breast cancer tissues there was also a higher expression of these two genes than in normal cells. The investigators concluded, therefore, that, "Our findings demonstrate a role for Orai1 and STIM1 in tumor metastasis and suggest store-operated calcium entry channels as potential cancer therapeutic targets.”

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Weill Cornell Medical College