MiRNA-199a-3p通过mTOR通路与阿霉素联合抑制子宫内膜癌细胞的增殖和促凋亡作用

目的:探讨阿霉素对转染miRNA-199a-3p的子宫内膜癌(EC)的作用及机制。方法:构建pSIREN-miRNA-199a-3p过表达质粒并稳定转染内膜癌细胞系Ishikawa、SPEC-2细胞。应用逆转录PCR(RT-PCR)检测miRNA-199a-3p的表达;MTT、克隆形成实验检测细胞增殖;流式细胞术检测细胞凋亡;Western blot检测mTOR信号通路相关蛋白表达。结果:上调miRNA-199a-3p可显著抑制子宫内膜癌细胞Ishikawa、SPEC-2的克隆形成能力(P0.01,P0.05);miRNA-199a-3p可增强阿霉素对Ishikawa、SPEC-2细胞的生长抑制(P均0.05)和凋亡诱导作用(P均0.05);Western blot证实,miRNA-199a-3p可显著下调mTOR及其效应蛋白p70S6K的磷酸化水平。结论:miRNA-199a-3p可能通过mTOR通路与阿霉素联合抑制子宫内膜癌细胞的增殖并促进其凋亡,为联合应用miRNA和阿霉素治疗EC提供了实验依据。     

Subannular Mitral Prosthesis in Aortic Position

Björk-Shiley subannular mitral prostheses have been used in the aortic position in 36 patients with calcific aortic annulus. We believe that the flange in the sewing ring of these prostheses offers added protection against perivalvular leakage; over an 18-month period there have been no instances of periprosthetic leakage in these patients.     

Reduction of TSG101 protein has a negative impact on tumor cell growth

TSG101 was defined originally as a tumor-suppressor gene, raising the expectation that absence of the encoded protein should lead to increased tumor cell growth and, perhaps, increased tumor cell aggressiveness. We have used the RNA interference (RNAi) technique to downregulate TSG101 in PC3 (prostate cancer) and MDA-MB-231 (breast cancer) cells. An approximately 85% selective downregulation at the protein level was achieved in both cell lines over a period of 12 days as detected by Western blotting. This treatment resulted in inhibition of tumor cell growth, with a decreased level of TSG101 causing partial cell cycle arrest at the G(1)/S boundary and a reduction in the rate at which cells passed from G(2) through mitosis and back into G(1). In both cell lines, the percentage of cells in S-phase was reduced significantly at day 4 after the TSG101 siRNA transfection (27% vs. 41% in MDA-MB-231 cells; 22% vs. 39% in PC3 cells). Additionally, RNAi-mediated downregulation of TSG101 reduced the colony formation capacities of both cancer cell lines. Rather more surprisingly, TSG101 downregulation affected the migratory activity of the MDA-MB-231 cells, independent of any effect on proliferation. Thus, in a Transwell assay, after 4-hr incubation, 36.0% of control MDA-MB-231 cells had migrated to the lower chamber vs. 7.3% of TSG101-downregulated cells (p < 0.001; scrambled control, 36.5%). These results show that the TSG101 gene does not comply with the usual characteristics of a tumor-suppressor gene; rather, its expression may be necessary for activities associated with aspects of tumor progression.     

Inhibition of primary colon carcinoma growth and liver metastasis by the A3 adenosine receptor agonist CF101

Adenosine is a purine nucleoside that acts as a regulatory molecule by binding to specific G-protein-coupled A1, A(2A), A(2B), and A3 cell surface receptors. We have recently demonstrated that adenosine inhibits tumour cell growth and concomitantly stimulates bone marrow cell proliferation via activation of the A3 adenosine receptor (A3AR). In the present study, we show that a synthetic agonist to the A3AR, CF101, at the low nanomolar concentration range, inhibits HCT-116 human colon carcinoma cell growth. This effect was reversed by the selective A3AR antagonist MRS1523, demonstrating the specificity of the response. CF101 (given orally) was efficacious in inhibiting the development of primary tumours in xenograft and syngeneic models in which mice were inoculated subcutaneously with human HCT-116 or murine CT-26 colon carcinoma cells, respectively. Moreover, CF101 suppressed (50%, P<0.01) colon cancer liver metastases in syngeneic mice inoculated to the spleen with CT-26 cells. The mechanism of action entailed upregulation of interleukin-12 production in the CF101-treated groups and potentiation of NK cell activity. In the HCT-116 xenograft model in which a combined therapy of CF101 and 5-fluorouracyl (5-FU) was examined, an additive antitumour effect was demonstrated. Moreover, CF101 prevented the 5-FU-induced myelotoxicity, resulting in normal values of white blood cell and neutrophil counts. We conclude that the A3AR agonist CF101, a small orally bioavailable molecule, exerts systemic anticancer, antimetastatic, and myeloprotective effects in colon carcinoma-bearing mice, and may serve as an adjuvant treatment to enhance the chemotherapeutic index and prevent myelotoxicity.     

Inhibited growth of colon cancer carcinomatosis by antibodies to vascular endothelial and epidermal growth factor receptors

Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) regulate colon cancer growth and metastasis. Previous studies utilizing antibodies against the VEGF receptor (DC101) or EGF receptor (C225) have demonstrated independently that these agents can inhibit tumour growth and induce apoptosis in colon cancer in in vivo and in vitro systems. We hypothesized that simultaneous blockade of the VEGF and EGF receptors would enhance the therapy of colon cancer in a mouse model of peritoneal carcinomatosis. Nude mice were given intraperitoneal injection of KM12L4 human colon cancer cells to generate peritoneal metastases. Mice were then randomized into one of four treatment groups: control, anti-VEGFR (DC101), anti-EGFR (C225), or DC101 and C225. Relative to the control group, treatment with DC101 or with DC101+C225 decreased tumour vascularity, growth, proliferation, formation of ascites and increased apoptosis of both tumour cells and endothelial cells. Although C225 therapy did not change any of the above parameters, C225 combined with DC101 led to a significant decrease in tumour vascularity and increases in tumour cell and endothelial cell apoptosis (vs the DC101 group). These findings suggest that DC101 inhibits angiogenesis, endothelial cell survival, and VEGF-mediated ascites formation in a murine model of colon cancer carcinomatosis. The addition of C225 to DC101 appears to lead to a further decrease in angiogenesis and ascites formation. Combination anti-VEGF and anti-EGFR therapy may represent a novel therapeutic strategy for the management of colon peritoneal carcinomatosis.