SGT1 regulates Akt signaling by promoting beta-TrCP-dependent PHLPP1 degradation in gastric cancer cells.

SGT1 (suppressor of G2 allele of Skp1) plays a role in various cellular processes including kinetochore assembly and protein ubiquitination by interacting with Skp1, a component of SCF E3 ligase complex. However, the function of SGT1 in cancer is largely unknown. Here, we showed that SGT1 was over-expressed in gastric cancer tissues and silencing of SGT1 by siRNAs significantly inhibited the growth and colony formation of gastric cancer cells. We further showed that SGT1 could regulate Akt signaling pathway by modulating Akt ser473 phosphorylation status. Moreover, we found that SGT1 was able to regulate the stability of PHLPP1, which is the direct phosphatase for Akt ser473 phosphorylation. Immunoprecipitation assay revealed that SGT1 could enhance the binding between PHLPP1 and beta-TrCP which has been documented to be able to target PHLPP1 for destruction. Decreased PHLPP1 in SGT1 over-expressed gastric cancer cells failed to dephosphorylate Akt and resulted in increased Akt ser473 phosphorylation and amplified downstream Akt signaling. Thus, our data revealed a previously uncovered role of SGT1 in gastric cancer development, and suggested that SGT1 could be a promising anti-cancer target to against gastric cancer.

The association of polymorphisms on TGFBR1 and colorectal cancer risk: a meta-analysis.

Epidemiological studies found inconsistent results on the association of two variants on TGFBR1 (TGFBR1*6A and Int7G24A) with colorectal cancer (CRC) risk. The present study was aimed to evaluate the association of these two variants with CRC susceptibility via the meta-analysis methods. For variant TGFBR1*6A, nine reports including 6,765 CRC patients and 8,496 unrelated controls were identified. The heterozygotes *6A/*9A showed a significant increased risk of CRC with the pooled OR was 1.12 (95% CI = 1.02-1.23), and the pooled OR for the homozygotes *6A/*6A was 1.13 (95% CI = 0.80-1.58) compared to the homozygotes *9A/*9A. However, under the dominant effect model, the TGFBR1*6A carriers showed a significantly increased CRC risk (pooled OR = 1.12, 95% CI = 1.03-1.23, *6A/*6A and *6A/*9A vs. *9A/*9A). For variant Int7G24A, three case-control studies with 1,074 cases and 1,945 controls were found. Although no significant association was found for heterozygosity Int7G24A carriers with CRC risk (pooled OR = 0.97, 95% CI = 0.67-1.42), the homozygosity A/A carriers showed a significant elevated risk of CRC (pooled OR = 1.68, 95% CI = 1.14-2.47) compared to G/G homozygotes. Under the recessive effect model, homozygotes A/A showed a 71% increase of CRC risk compared to the A/G and G/G genotype carriers (pooled OR = 1.71, 95% CI = 1.17-2.51). These data strongly suggested that the two polymorphisms of TGFBR1 may confer low-penetrance susceptibility of CRC risk.

Expression of vascular endothelial growth factor C and anti-angiogenesis therapy in endometriosis.

Angiogenesis is an important pathogenesis of Endometriosis. Vascular endothelial growth factor C (VEGF-C) is one of the most important factor in the regulation of both normal and abnormal angiogenesis. Anti-angiogenic treatment of endometriosis is still in the exploratory stage. In this study, we investigate the relationship between VEGF-C and endometriosis, the therapeutic effects of Endostar in the rat endometriosis model. We then demonstrated that Immunohistochemical expression of VEGF-C was higher in endometriotic tissues than in control normal ovary tissues (P < 0.01) and higher in the endomertriosis grade III-IV than in endomertriosis grade I-II (P=0.013). In rat endometriosis model, we observed a significant reduction in the mean volume and weight of the endometriotic implants per rat in the treatment group as compared with the control group. By immunohistochemical evaluation, there was a significant reduction in VEGF-C expression after treatment in all areas examined. VEGF-C may be involved in the pathogenesis of endomertriosis by regulating the angiogenesis. Endostar has therapeutic effects of endometriosis lesions in the rat endometriosis model.

Estrogen receptor-regulated microRNAs contribute to the BCL2/BAX imbalance in endometrial adenocarcinoma and precancerous lesions.

Uncontrolled estrogen exposure can induce an imbalance in BCL2/BAX expression in endometrial cells, leading to precancerous lesions and type I endometrial adenocarcinoma. This study aimed to explore the mechanism underlying this phenomenon. We show that the activated estrogen receptor can suppress the expression of BAX by upregulating a group of microRNAs including hsa-let-7 family members and hsa-miR-27a, thereby promoting an increased BCL2/BAX ratio as well as enhanced survival and proliferation in the affected cells. These ER-regulated hsa-let-7 microRNAs can be detected in most hyperplastic endometria, suggesting their potential utility as indicators of estrogen over-exposure.