Protein tyrosine phosphatase receptor-type O (PTPRO) exhibits characteristics of a candidate tumor suppressor in human lung cancer

AUTOR(ES)

Motiwala, Tasneem

FONTE

National Academy of Sciences

RESUMO

Previous study in our laboratory demonstrated suppression of the gene for protein tyrosine phosphatase receptor-type O (PTPRO) in primary and established rat hepatomas. The present study showed methylation-mediated silencing of this gene in primary human lung tumors and in several human lung cancer cell lines, one of the characteristics of many tumor-suppressor genes. The reduced expression of PTPRO in the primary lung tumors correlated with the methylation status of its CpG island. Demethylation of the gene by deoxy-5-azacytidine treatment led to its reactivation in a lung cancer line (A549). Overexpression of PTPRO in A549 cells inhibited anchorage-independent growth, delayed reentry of the cells into the cell cycle after release from cell-cycle arrest, and increased susceptibility of the cells to apoptosis. These data have demonstrated the growth-suppressor characteristics of PTPRO that are unique to a classical tumor suppressor.

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