Inhibition of the proliferation of human gastric cancer cells SGC-7901 in vitro and in vivo using Bcl-2 siRNA / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Bcl-2, the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of Bcl-2, RNA interference (RNAi) was used to inhibit Bcl-2 expression in the human gastric cancer cells in vitro and in vivo.</p><p><b>METHODS</b>Bcl-2 small interfering RNA (siRNA) was transfected into human gastric cancer cells SGC-7901, and Bcl-2 expression was monitored by real-time polymerase chain reaction (PCR) and Western blot. Cell proliferation, apoptosis, and telomerase activity were examined by MTT, flow cytometry, and TRAP assay, respectively. Gastric cancer cells treated with 100 nmol/L Bcl-2 siRNA were subcutaneously transplanted into nude mice and tumor growth was assessed.</p><p><b>RESULTS</b>Bcl-2 siRNA significantly inhibited the expression of Bcl-2 in human gastric cancer cells at both mRNA and protein levels in a time- and dose-dependent manner. Bcl-2 siRNA also decreased telomerase activity (by 78.76%) and increased the rate of apoptosis (by 37.47%). SGC-7901 cell growth was also significantly suppressed in vivo and in vitro.</p><p><b>CONCLUSIONS</b>Bcl-2 expression knockdown suppressed the growth of gastric cancer cells. Thus, Bcl-2 may play a very important role in carcinogenesis of gastric cancer and its knockdown may offer a new potential gene therapy approach for human gastric cancer in future.</p>

In vitro chemo-sensitivity MTT assay guided intraperitoneal chemotherapy for malignant ascites / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and efficacy of intraperitoneal chemotherapy for malignant ascites caused by different types of abdominal cancers guided by chemo-sensitivity methyl tetrojolium coloremetric (MTT) assay in vitro.</p><p><b>METHODS</b>Cancer cells in the malignant ascites were collected for MTT assay to determine the chemo-sensitivity. The drug producing the highest or the second highest inhibition rate was selected for intraperitoneal chemotherapy. The correlation between the results of MTT assay and the response of malignant ascites, the clinical features, Karnofsky performance score (KPS) and prognosis were analyzed.</p><p><b>RESULTS</b>MTT assay indicated that Taxotere (TXT) and Hydroxycamptothecin (HCPT) were the most effective to cancer cells in malignant ascites, and HCPT was mostly frequently used for intraperitoneal chemotherapy (56.9%). Twenty-four patients showed response by intraperitoneal chemotherapy (complete response: 7; partial response: 17) with a slightly significant correlation between the results of MTT assay and response of malignant ascites (P = 0. 014). The KPS of the responders was improved significantly (P < 0.001), and the response of malignant ascites to intraperitoneal chemotherapy was demostrated as an independent prognostic factor by multi-variate analysis in this series.</p><p><b>CONCLUSION</b>In vitro chemo-sensitivity MTT assay guided intraperitoneal chemotherapy for malignant ascites is simple, effective and safe, which can improve the KPS and prognosis of the responders.</p>

uPA expression of gastric cancer cell lines and its correlation with peritoneal seeding / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the correlation between expression of urokinase-type plasminogen activator (uPA) and capability of tumor cell seeding to the peritoneal membrane by different gastric cancer lines.</p><p><b>METHODS</b>Expression of uPA in 4 human gastric cancer cell lines was examined by semi-quantitative RT-PCR, ELISA and Western blot. uPA activity was determined by an assay kit. After ip inoculation of cancer cells to nude mice, tumors on peritoneal membrane was grossly examined for tumor cell seedings.</p><p><b>RESULTS</b>SGC7901 was the highest in uPA expression among human gastric cancer cell lines AGS, SGC7901, MKN45, and MKN28. MKN45 had the strongest uPA activity, while AGS was lowest in both uPA expression and activity. Peritoneal seeding tumors of various sizes were observed in mice inoculated with SGC7901 and MKN45 cells. In addition to peritoneal seedings, bloody ascites was present in mice inoculated with MKN28. The MKN45-inoculated mice took the least time to develop tumors and had the shortest surviving period. No peritoneal seeding was seen in mice inoculated with AGS cells.</p><p><b>CONCLUSION</b>Three of 4 human gastric cancer cell lines studied express uPA mRNA and activity, which correlate with their peritoneal seeding potentials.</p>

Relationship between urokinase-type plasminogen activator expression and peritoneal metastatic potency in different gastric cancer cell lines / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To compare the expression and activities of urokinase type plasminogen activator (uPA) among different gastric cancer cell lines and investigate their relations with peritoneal metastatic potency.</p><p><b>METHODS</b>The uPA expression in 4 gastric cancer cell lines (AGS, SGC7901, MKN45, MKMN28) was detected using ELISA and Western blot methods. uPA activity was detected simultaneously using uPA activity kit. The gastric cancer cells were cultured with confluent mesothelial cells in 24-well plates or Boyden chambers for different times. The adhesive cells were counted directly under a microscope. The motility and invasion of gastric cancer cells were determined by MTT assay.</p><p><b>RESULTS</b>Among four gastric cancer lines,the highest expression of uPA was found in SGC7901 and the highest uPA activity in MKN45, while the lowest expression and activity of uPA in AGS. Compared with the other three lines, MKN45 had stronger adhesion than MKMN28 (P< 0.05), SGC7901 (P< 0.05), and AGS (P< 0.01), but there were no significant differences in motility and invasion among MKN45, MKN28 and SGC7901. The adhesion,motility and invasion of AGS were weaker compared with those of the other three cell lines.</p><p><b>CONCLUSION</b>The uPA expression and activity are significantly different among 4 gastric cancer cell lines, and positively correlated with their peritoneal metastatic potency.</p>