mTOR signaling is involved in indomethacin and nimesulide suppression of colorectal cancer cell growth via a COX-2 independent pathway.

BACKGROUND: Inhibition of mammalian target of rapamycin (mTOR) represents an attractive target for anticancer therapy, but its role in suppression of colorectal cancer (CRC) cell growth by cyclooxygenase-2 (COX-2) inhibitors is unclear. Here, we analyzed the effect of indomethacin (Indo, a nonselective COX-2 inhibitor) and nimesulide (Nim, a selective COX-2 inhibitor) on mTOR signaling in CRC cells in vitro and in vivo to determine the dependence of this effect on COX-2. METHODS: Human CRC cell lines with varying COX-2 expression levels were treated with Indo and Nim. Western blot test was performed to detect mTOR-related components (mTOR, p70s6 K, and 4EBP1), and cell viability, cell cycle, and apoptosis were assessed. HCT116 and SW1116 cells were injected into athymic nude mice to establish a CRC xenograft model. After treatment with Nim, tumor volume, mTOR signaling, and apoptosis were evaluated in this model. HT29 and SW1116 cells were also treated with Nim after transfection with COX-2-specific small interfering RNA (siRNA) to assess dependence of COX-2 on mTOR signaling under drug treatment. RESULTS: Both Indo and Nim reduced mTOR signaling activity in CRC cells that differ in their COX-2 expression in vitro and in vivo. Additionally, Indo and Nim could reduce the mTOR signaling activity after COX-2 silencing in CRC cells. CONCLUSIONS: mTOR signaling is involved in Indo- and Nim-mediated suppression of CRC growth via a COX-2 independent pathway. This study unveils a novel mechanism through which COX-2 inhibitors exerts their anticancer effects and further emphasizes targeting mTOR signaling in anticancer therapy.

Human macrophage metalloelastase correlates with angiogenesis and prognosis of gastric carcinoma.

BACKGROUND AND AIMS: The function of human macrophage metalloelastase (HME) also known as matrix metalloproteinase 12, in tumorigenesis is contradictory. The current study was designed to investigate the association of HME expression with angiogenesis and prognosis of gastric carcinomas. METHODS: In situ hybridization and immunohistochemistry were used to detect HME in human gastric carcinomas, chronic gastritis with atypical hyperplasia, and normal gastric epithelium mucosa. The results were further confirmed by RT-PCR or semi-quantitative reverse transcription polymerase chain reaction and Western blotting in gastric carcinomas and paired noncancerous tissues. VEGF and microvessel density count were also detected by immunohistochemical staining in all carcinoma tissues. The prognostic significance of HME was assessed with multiple linear regression analysis and Cox proportional hazards model. RESULTS: High expression of HME protein/mRNA was observed in gastric carcinomas and atypical hyperplasia tissues compared with normal gastric epithelium mucosa, or paired noncancerous tissues. HME protein/mRNA were negatively correlated with MVD (p < 0.01), VEGF (p < 0.01), tumor differentiation grade (p < 0.05), vascular invasion (p < 0.01), and recurrence (p < 0.05-0.01). HME protein was an independent influential factor of MVD (p < 0.01). HME protein/mRNA was an independent prognostic factor of gastric carcinoma (p < 0.05-0.01). Patients with overexpression of HME protein/mRNA demonstrated a significantly better survival rate compared with those who did not (p < 0.05-0.01). CONCLUSIONS: Overexpression of HME is strongly correlated with the reduced angiogenesis and vascular invasion of gastric carcinoma, and may serve as a useful predictive indicator in patients with this disease.

Effect of sea buckthorn on liver fibrosis: a clinical study.

AIM: To appraise the effect of sea buckthorn (Hippophae rhamnoides) on cirrhotic patients. METHODS: Fifty cirrhotic patients of Child-Pugh grade A and B were randomly divided into two groups: Group A as the treated group (n=30), taking orally the sea buckthorn extract, 15 g 3 times a day for 6 months. Group B as the control group (n=18), taking vitamin B complex one tablet, 3 times a day for 6 months. The following tests were performed before and after the treatment in both groups to determine LN, HA, collagens types III and IV, cytokines IL-6 and TNFalpha, liver serum albumin, total bile acid, ALT, AST and prothrombin time. RESULTS: The serum levels of TNFalpha, IL-6, laminin and type IV collagen in group A were significantly higher than those in the control group. After a course of sea buckthorn treatment, the serum levels of LN, HA, collagen types III and IV, total bile acid (TBA) decreased significantly as compared with those before and after treatment in the control group. The sea buckthorn notably shortened the duration for normalization of aminotransferases. CONCLUSION: Sea buckthorn may be a hopeful drug for prevention and treatment of liver fibrosis.