BACKGROUND: Up-regulation of the hepatocyte growth factor (HGF), its transmembrane tyrosine kinase receptor (c-Met), and urokinase type plasminogen activator (uPA), is associated with the development and metastasis of various types of cancers. However, the mechanisms by which HGF/c-Met signaling mediates cancer progression and metastasis are unclear. METHODS: We investigated the roles of HGF/c-Met in tumor progression and metastasis in NUGC-3 and MKN-28 stomach cancer cell lines. RESULTS: Treatment with HGF increased c-Met phosphorylation in a dose-dependent manner, as well as increasing cell proliferation. HGF treatment also increased the protein level and the activity of uPA in NUGC-3 and MKN-28 cells. A monoclonal antibody against human uPA receptor (uPAR), mAb 3936, inhibited HGF-mediated tumor cell invasion in a dose-dependent manner. Down-regulation of uPA using uPA-shRNA induced a decrease in in vitro cell invasion in NUGC-3 cells. CONCLUSIONS: These results suggest that NUGC-3 and MKN-28 cells express functional c-Met, which may provide a therapeutic target for interfering with metastases of cancer cells by inhibiting uPA and uPAR-mediated proteolysis.
Urinary Plasminogen Activator/antagonists & inhibitors/*metabolism ; Stomach Neoplasms/drug therapy/*enzymology ; Signal Transduction/*drug effects ; Receptors, Growth Factor/*drug effects ; Receptor Protein-Tyrosine Kinases/*drug effects ; Proto-Oncogene Proteins c-met/*drug effects ; Neoplasm Metastasis ; Humans ; Hepatocyte Growth Factor/*metabolism ; Disease Progression ; Adenocarcinoma/drug therapy/enzymology

OBJECTIVETo investigate the relationship between polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) C677T or A1298C and the response to fluoropyrimidine (5-FU)-based chemotherapy in advanced stomach cancer (SC).

METHODS75 cases with advanced SC were analyzed. All patients were treated with 5-FU-based chemotherapy and DNA of peripheral blood leukocytes was obtained before therapy. MTHFR genotypes were detected by PCR-RFLP method.

RESULTS(1) Of all the cases, the frequencies of MTHFR C677T C/C, C/T and T/T genotype were 32.0%, 44.0% and 24.0%, while the frequencies of MTHFR A1298C A/A, A/C and C/C genotype were 69.3%, 29.3% and 1.3%, respectively. The overal response rate to 5-FU-based chemotherapy was 29.3%. (2) The response rate to therapy among MTHFR C677T T/T genotype patients (83.3%) was significantly higher than the C677T C/T genotype (15.2%, chi(2) = 22.27, P = 0.000) or the C677T C/C genotype (8.3%, chi(2) = 23.44, P = 0.000). As compared with patients with C677T C allele, patients with C677T T/T genotype had a 7.64-fold sensitivity to 5-FU-based chemotherapy (adjusted for sex, age, prior adjuvant therapy and chemotherapy program, 95% CI: 3.14 - 18.62). The response rate to therapy among patients with MTHFR A1298C A/A genotype (36.5%) was significantly higher than patients with A1298C C allele (13.0%, chi(2) = 4.19, P = 0.041, adjusted OR = 3.75, 95% CI: 0.94 - 14.87). The response rate to therapy among patients with MTHFR C677T T/T and A1298C A/A genotypes (86.7%) was significantly higher than other groups of C677T and A1298C genotypes (15.0%, Fisher exact: P = 0.000, adjusted OR = 6.57, 95% CI: 2.8 - 15.6). (3) The incidence rates of nausea/vomiting in MTHFR C677T T/T, C/T or A1298C A/A genotypes were significantly higher than other genotypes, but the incidence rates of other treatment-related adverse reaction in MTHFR C677T or A1298C genotypes were not significantly different.

CONCLUSIONThese results in the present study suggested that the polymorphisms of MTHFR were associated with clinical response to 5-FU-based chemotherapy, suggesting that MTHFR genotypes could identify advanced SC patients that would be responsive to 5-FU-based chemotherapy.

Adult ; Aged ; Antimetabolites, Antineoplastic ; therapeutic use ; Drug Resistance, Neoplasm ; genetics ; Female ; Fluorouracil ; therapeutic use ; Genotype ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Stomach Neoplasms ; drug therapy ; enzymology

OBJECTIVETo observe the effect of polo like kinase 1 (plk1) gene depletion on the growth of gastric cancer cell line-MKN45 cells in vitro and vivo and discuss the feasibility and effectiveness of arranging plk1 as gene therapeutic target for gastric cancer.

METHODSThe plk1 expression of MKN45 cells was inhibited by RNA interference (RNAi). The plk1 mRNA and protein level were measured by real-time quantitative PCR and western blotting, and the change of cell cycle distribution and apoptosis rate were detected by flow-cytometry, and the MKN45 cells proliferation was measured by MTT method. MKN45 cells treated with plk1 siRNA were transplanted subcutaneously in nude mice and their tumorgenesis ability were observed, the plk1 protein levels of the samples from nude mice in different groups were compared.

RESULTSAfter treatment with plk1 siRNA, plk1 mRNA and protein level decreased obviously in certain time, more MKN45 cells accumulated at G(2)/M (P < 0.05). Apoptosis rate of MKN45 cells treated with plk1 siRNA was higher than that of control cells at 48 h and 72 h (P < 0.05), and MKN45 cells proliferated slowly than control groups (P < 0.05), while the tumorgenesis ability obviously decreased, but the plk1 protein levels of the samples from nude mice in different groups were not different.

CONCLUSIONSsiRNA targeting plk1 can inhibit the proliferation of MKN45 cells in vitro and vivo. Plk1 may be a novel therapeutic target for gastric cancer.

Animals ; Apoptosis ; drug effects ; Cell Cycle Proteins ; drug effects ; genetics ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Male ; Mice ; Mice, Nude ; Protein-Serine-Threonine Kinases ; drug effects ; genetics ; Proto-Oncogene Proteins ; drug effects ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; pharmacology ; Stomach Neoplasms ; drug therapy ; enzymology ; pathology ; Transfection

The aim of the study was to investigate the anti-proliferation and apoptosis-inducing effects of S1, a novel tetrandrine derivative, in human gastric cancer BGC-823 cells and explore the possible mechanism of action. The anti-proliferative activity was determined by MTT assay; the induction of cell cycle arrest and apoptosis were detected by flow cytometry. Quantitative real time RT-PCR and Western blotting were used to evaluate the mRNA and protein expression levels in mitochondrial pathway. S1 significantly reduced cell viability and induced a G2/M phase arrest and apoptosis in dose- and time-dependent manner. Further studies showed that S1 increased mRNA and protein expression of Bax and the Bax/Bcl-2 ratio. Moreover, S1 decreased the protein expression of procaspase-9 and procaspase-3, suggesting that the induction of apoptosis may be related to the alteration of the ratio of Bax/Bcl-2 and the activation of caspases. These findings suggested that S1 merits further investigation as a novel therapeutic agent for the treatment of human gastric cancer.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Benzylisoquinolines ; chemistry ; pharmacology ; Caspase 3 ; genetics ; metabolism ; Caspase 9 ; genetics ; metabolism ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Humans ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Stomach Neoplasms ; drug therapy ; enzymology ; genetics ; physiopathology ; bcl-2-Associated X Protein ; genetics ; metabolism

Although medical treatment has been shown to improve quality of life and prolong survival, no significant progress has been made in the treatment of advanced gastric cancer (AGC) within the last two decades. Thus, the optimum standard first-line chemotherapy regimen for AGC remains debatable, and most responses to chemotherapy are partial and of short duration; the median survival is approximately 7 to 11 months, and survival at 2 years is exceptionally > 10%. Recently, remarkable progress in tumor biology has led to the development of new agents that target critical aspects of oncogenic pathways. For AGC, many molecular targeting agents have been evaluated in international randomized studies, and trastuzumab, an anti-HER-2 monoclonal antibody, has shown antitumor activity against HER-2-positive AGC. However, this benefit is limited to only ~20% of patients with AGC (patients with HER-2-positive AGC). Therefore, there remains a critical need for both the development of more effective agents and the identification of molecular predictive and prognostic markers to select those patients who will benefit most from specific chemotherapeutic regimens and targeted therapies.
Angiogenesis Inhibitors/therapeutic use ; Animals ; Antineoplastic Agents/*therapeutic use ; Humans ; *Molecular Targeted Therapy ; Protein Kinase Inhibitors/therapeutic use ; Receptor, Epidermal Growth Factor/antagonists & inhibitors/metabolism ; Receptor, erbB-2/antagonists & inhibitors/metabolism ; Signal Transduction/drug effects ; Stomach Neoplasms/*drug therapy/enzymology/genetics/pathology ; Treatment Outcome

OBJECTIVETo observe the effect of drug-containing serum of Chinese traditional herbal decoction Weikangning (WKN) on growth of gastric cancer cell, expression of vascular endothelial growth factor (VEGF) and its receptors including KDR and Flt-1.

METHODSA total of 120 male Wistar rats were given high, medium and low-dose WKN. After the drug-containing serum was prepared, the gastric cancer cells MGC-803 of different dose groups were cultured with the drug-containing serum, respectively. The gastric cell growth was observed by using light microscope and flow cytometer,the expression of VEGF and its receptor Flt-1 was detected with SABC immunohistochemistry method and the mRNA expression levels of VEGF and its receptors including KDR and Flt-1 of different groups were detected with reverse transcription-polymerase chain reaction (RT-PCR), respectively.

RESULTSThe gastric cancer cell growth and cell cycle of the three medicated groups were significantly improved as compared with those of the control group (P <0. 01) ,the proportion of cells in G0 - G1 phase was increased,while the cells in S phase were decreased. It was shown that the apoptotic rates were increased in the medicated groups in a dose-dependent manner. The gray scales ( microm(2) ) of VEGF and Flt-1 in high, medium and low dose groups was 182. 44 +/-0. 54,178. 65 +/-0. 56,174. 80 +/-0. 81 and 168. 51 +/- 0. 81,162. 01 +/-0. 52,148. 20 +/-0. 69, respectively vs 147.82 +/-0. 15(P <0.01) and 144.31 +/-0.71 (P <0.01) in the control group. The mRNA expression of VEGF and its receptors significantly decreased in gastric cancer cells after cultured with WKN contained serum (P < 0. 01 ).

CONCLUSIONWKN has inhibitory effects on gastric cancer cell growth and mRNA expression of VEGF as well as its receptors KDR and Flt-1.

Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; therapeutic use ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Male ; Rats ; Rats, Wistar ; Stomach Neoplasms ; drug therapy ; enzymology ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism ; Vascular Endothelial Growth Factor Receptor-1 ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

BACKGROUNDThe importance of polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene for the prediction of the response to fluorouracil-based adjuvant chemotherapy in gastric cancer patients remains unclear. The aim of this study is to assess the predictive value of several polymorphisms of the MTHFR gene for clinical outcomes of gastric cancer patients treated with fluorouracil-based adjuvant chemotherapy in Chinese population.

METHODSThree hundred and sixty-two Chinese patients with gastric cancer were treated with fluorouracil-based adjuvant chemotherapy. DNA samples were isolated from peripheral blood collected before treatment. The three single nucleotide polymorphisms (SNPs) (rs1801131, rs1801133, rs2274976) genotypes of the MTHFR gene were determined by matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

RESULTSThe average response rate for chemotherapy was 46.7%. Homozygous genotypes rs2274976G/G (χ(2) = 22.7, P < 0.01) and rs1801131A/A (χ(2) = 14.3, P = 0.008) were over-represented in responsive patients. Carriers of the rs2274976A allele genotypes (G/A and A/A) and of the rs1801131C allele genotypes (A/C and C/C) were prevalent in nonresponsive patients. In the haplotype association analysis, there was a significant difference in global haplotype distribution between the groups (χ(2) = 20.69, P = 0.000 124).

CONCLUSIONSThese results suggest that polymorphisms of the MTHFR gene may be used as predictors of the response to fluorouracil-based chemotherapy for gastric cancer patients in Chinese population. Well-designed, comprehensive, and prospective studies on determining these polymorphisms of MTHFR gene as clinical markers for predicting the response to fluorouracil-based therapy in gastric cancer patients is warranted.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antimetabolites, Antineoplastic ; therapeutic use ; Asian Continental Ancestry Group ; Female ; Fluorouracil ; therapeutic use ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Prospective Studies ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Stomach Neoplasms ; drug therapy ; enzymology ; genetics ; Young Adult