Rabbit Anti-Human CDC25A Polyclonal Antibody

The Src homology 2 (SH2) domain-containing phosphatase 2 (SHP-2) is a nonreceptor protein tyrosine phosphatase (PTP) involved in extracellular-regulated kinase (ERK) activation. Recent studies have shown that gain-of-function mutations in SHP-2 are associated with several diseases, including LEOPARD syndrome, Noonan syndrome, and juvenile myelomonocytic leukemia. In this study, we identified the novel SHP-2 inhibitor 3-(1-benzimidazolylmethyl)-6-p-tolyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole (MLS-001). SHIP-2 activity was inhibited by MLS-001, whereas other types of PTPs, namely ACP1, CDC25A, DUSP3, DUSP14, DUSP18, DUSP22, DUSP23, DUSP26, and SSH3, were not. Furthermore, TCPTP and SHP-1 that are closely related to SHP-2 were not inhibited by the inhibitor. Kinetic studies with MLS-001 and SHP-2 revealed a competitive inhibition. The SHP-2 expressing cells treated with MLS-001 demonstrated reduced SHP-2 phosphatase activity, thereby suggesting that MLS-001 effectively passes through cell membranes. In addition, MLS-001 reduced SHP-2-mediated phosphorylation in the activation loop of ERK in cells. Therefore, MLS-001 could be a lead compound for developing a potent SHP-2 inhibitor.

miR-449a, a novel tumor suppressor, is deregulated in various malignancies, including prostate cancer. Overexpression of miR-449a induces cell cycle arrest, apoptosis, and senescence, but its role in response to ionizing radiation and underlying molecular mechanism are still unknown. Here, we report that miR-449a enhances radiation-induced G2/M phase arrest and apoptosis through modulating pRb/E2F1 and sensitizes prostate cancer cells to X-ray radiation. In wild-type Rb PC-3 cells, overexpression of miR-449a enhances radiation-induced G2/M arrest and apoptosis and promotes the sensitivity to X-ray radiation. While mutant Rb DU-145 cells are resistant to the X-ray radiation despite in the presence of miR-449a. The cell cycle distribution of DU-145 cells is not significantly altered by miR-449a in the response to ionizing radiation. Furthermore, elevated miR-449a downregulates cell cycle regulator CDC25A and oncogene HDAC1. By targeting genes involved in controlling pRb/E2F1 activity, miR-449a regulates cell cycle progression and apoptosis and consequently enhances the radiosensitivity of PC-3 cells. Thus, miR-449a, as a miRNA component of the Rb pathway, promotes the radiosensitivity of PC-3 cells through regulating pRb/E2F1.