Cellular density-dependent down-regulation of EP4 prostanoid receptors via the up-regulation of hypoxia-inducible factor-1α in HCA-7 human colon cancer cells.

ABSTRACT: Increases in prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) levels are features of colon cancer. Among the different E-type prostanoid receptor subtypes, EP4 receptors are considered to play a crucial role in carcinogenesis by, for example, inducing COX-2 when stimulated with PGE2. However, EP4 receptor levels and PGE2-induced cellular responses are inconsistent among the cellular conditions. Therefore, the connections responsible for the expression of EP4 receptors were investigated in the present study by focusing on cell density-induced hypoxia-inducible factor-1α (HIF-1α). The expression of EP4 receptors was examined using immunoblot analysis, quantitative polymerase chain reaction, and reporter gene assays in HCA-7 human colon cancer cells with different cellular densities. The

SUBMITTER: Otake S 

PROVIDER: S-EPMC4317221 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature