Spartina alterniflora invasion altered phosphorus retention and microbial phosphate solubilization of the Minjiang estuary wetland in southeastern China.

Spartina alterniflora invasion is considered a critical event affecting sediment phosphorus (P) availability and stock. However, P retention and microbial phosphate solubilization in the sediments invaded with or without S. alterniflora have not been fully investigated. In this study, a sequential fractionation method and high-throughput sequencing were used to analyze P transformation and the underlying microbial mechanisms in the sediments of no plant (NP) zone, transition (T) zone, and plant (P) zone. Results showed that except for organic phosphate (OP), total phosphate (TP), inorganic phosphate (IP), and available phosphate (AP) all followed a significant decrease trend from the NP site to the T site, and to the P site. The vertical decrease of TP, IP, and AP was also observed with an increase in soil depth. Among the six IP fractions, Fe-P, Oc-P, and Ca10-P were the predominant forms, while the presence of S. alterniflora resulted in an obvious P depletion except for Ca8-P and Al-P. Although S. alterniflora invasion did not significantly alter the alpha diversity of phosphate-solubilizing bacteria (PSB) harboring phoD gene, several PSB belonging to p_Proteobacteria, p_Planctomycetes, and p_Cyanobacteriota showed close correlations with P speciation and IP fractions. Further correlation analysis revealed that the reduced soil pH, soil TN and soil EC, and the increased soil TOC mediated by the invasion of S. alterniflora also significantly correlated to these PSB. Overall, this study elucidates the linkage between PSB and P speciation and provides new insights into understanding P retention and microbial P transformation in the coastal sediment invaded by S. alterniflora.

[Value of multidetector-row CT in the preoperative prediction of peritoneal metastasis from gastric cancer: a single-center and large-scale study].

OBJECTIVE: To investigate the value of multidetector-row computed tomography (MDCT) in preoperatively predicting peritoneal metastasis of gastric cancer and to evaluate the indication for laparoscopic staging of gastric cancer on the basis of MDCT features. METHODS: Six hundred and forty gastric cancer patients underwent preoperative MDCT examination, and the results of MDCT were compared with surgical and pathological findings. In addition, the relationship between MDCT features (depth of invasion, lymph node metastasis status, tumor size, and thickness of tumor) and peritoneal metastasis of gastric cancer was analyzed. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MDCT in predicting peritoneal metastasis of gastric cancer were 51.0% (25/49), 99.3% (587/591), 86.2% (25/29), 96.1% (587/611), and 95.6% (612/640), respectively. Univariable analysis showed that all the four MDCT features (depth of invasion, lymph node metastasis status, tumor size, and tumor thickness) of gastric cancer were significantly correlated with the peritoneal metastasis of gastric cancer. None of the patients diagnosed with stage T(0~2)N(x)M(0) or T(x)N(0)M(0) gastric cancer by MDCT were found to have peritoneal metastasis. Receiver operating characteristic (ROC) analysis showed that the accuracy of the tumor size and thickness of gastric cancer in determining peritoneal metastasis was high(area under ROC curve was 0.83 and 0.75, respectively). Multivariable analysis showed that only tumor size was significantly correlated with the peritoneal metastasis from gastric cancer. CONCLUSIONS: The clinical value of MDCT in preoperative prediction of peritoneal metastasis from gastric cancer is favorable. Laparoscopy can be avoided in patients with small tumor size or stage T(0~2)N(x)M(0) or T(x)N(0)M(0) gastric cancer diagnosed by MDCT due to lower incidence of peritoneal metastasis.

[A comparative study on the efficacy of spleen-preserving modified D2 radical gastrectomy and D2 radical gastrectomy with splenectomy].

OBJECTIVE: To compare the efficacy of modified D(2) radical total gastrectomy with spleen-preserving and D(2) radical total gastrectomy with splenectomy in patients with gastric cancer located in the upper third, upper and middle third and entire stomach. METHODS: One hundred and twelve patients with gastric cancer in the upper third, upper and middle third, or entire stomach underwent radical total gastrectomy between January 1989 and December 1994. Modified D(2) total radical gastrectomy with spleen-preserving (spleen-preservation group) was performed in 61 patients, and 51 underwent D(2) total radical gastrectomy with splenectomy (splenectomy group). The differences in clinicopathological characteristics,5-year survival rate, incidence of postoperative complication and hospital stay between the two groups were analyzed retrospectively. RESULTS: There were no significant differences between the spleen-preservation group and the splenectomy group in gender, age, tumor size, T stage, N stage and TNM stage. The overall 5-year survival rate was 41.0% in the spleen-preservation group and 39.2% in the splenectomy group (P>0.05). The 5-year survival rates of patients with stage I, II, III and IIII were 100%, 66.7%, 27.8% and 17.4% in the spleen-preservation group, respectively, and were 100%, 70.0%, 26.7% and 5.6% in the splenectomy group, respectively (all P>0.05). The incidence of postoperative complication was lower in the spleen-preservation group (11.5% vs 27.5%, P<0.05). The mean hospital stay was longer in the splenectomy group (27.3 d vs 20.3 d, P=0.057). CONCLUSION: The efficacy of modified D(2) radical total gastrectomy with spleen-preserving for patients with gastric cancer in the upper third, upper and middle third or entire stomach is similar to that of D(2) radical total gastrectomy with splenectomy, and the spleen-preserving procedure is associated with decreased postoperative complication and improved survival.

Value of multidetector-row computed tomography in the preoperative T and N staging of gastric carcinoma: a large-scale Chinese study.

OBJECTIVES: To investigate the value of multidetector-row computed tomography (MDCT) in the preoperative T and N staging of gastric carcinoma and to further investigate the clinicopathological factors affecting the diagnostic accuracy. METHODS: Seven hundred ninety gastric carcinoma patients underwent preoperative MDCT examination. The results of MDCT were compared with surgical and pathological findings. RESULTS: Early gastric carcinoma patients whose primary tumor was detected by MDCT had higher incidence of lymph node metastasis, larger tumor size, and deeper invasion. The overall accuracy of MDCT in determining T stage of gastric carcinoma was 73.80% (T1 45.93%, T2 53.03%, T3 86.49%, and T4 85.79%). The overall accuracy of MDCT in preoperative N staging was 75.22% (N0 76.17%, N1 68.81%, and N2 80.63%). The overall diagnostic sensitivity, specificity, and accuracy of MDCT for determining lymph node metastasis was 86.26%, 76.17%, and 82.09%, respectively. Multivariate analysis showed that the diagnostic sensitivity of MDCT in determining lymph node metastasis related with tumor size, N stage, and number of metastatic lymph nodes. CONCLUSIONS: The clinical value of MDCT in the preoperative T and N staging of gastric carcinoma is relatively high. MDCT can be the first choice for the preoperative evaluation of patients with gastric carcinoma.

Effect of surgical work volume on postoperative complication: superiority of specialized center in gastric cancer treatment.

PURPOSE: We investigated the risk factors for early postoperative complications after gastric cancer surgery. MATERIALS AND METHODS: The data from a total of 273 patients with gastric cancer were analyzed by univariate and multivariate analysis. We applied physiological and operative severity score for the enumeration of morbidity and mortality (POSSUM) to compare risk-adjusted surgical outcomes among different surgical units. RESULTS: Among the preoperative variables, patient gender, chronic obstructive pulmonary disease, surgical unit, and intraoperative blood loss were independent risk factors for a higher rate of postoperative complications. There were significant differences in complication rates among different surgical units (P = 0.001). The observed-to-expected morbidity ratio (O-to-E ratio) ranged from 0.81 to 1.63. Units with low surgical work volume had higher complication rates. Postoperative length of stay was significantly shorter (P = 0.000) and the rate of moderate and severe complications was significantly lower (P = 0.001) in specialized unit. CONCLUSIONS: POSSUM is a valid system for risk-adjusted evaluation of surgical outcomes. We conclude that surgical experience and work volume greatly influence the outcome, with overall surgical outcome in specialized centers superior to that in other units. Hence, gastric cancer surgery should be performed in specialized centers. Risk factors identified in this study need further confirmation by a prospective study involving a larger cohort.

[Prognostic significance of metastatic lymph nodes ratio in patients with T2-T3 stage gastric cancer].

OBJECTIVE: To evaluate the prognostic significance of metastatic lymph nodes ratio in patients with T(2)~T(3) stage gastric cancer. METHODS: Clinical data of 238 patients with T(2)-T(3) stage gastric cancer undergone radical gastrectomy and D(2) lymphadenectomy, at least 15 lymph nodes was dissected per patient, were analyzed retrospectively. Spearman correlation analysis was used to determine the correlation coefficient. Survival was determined by the Kaplan-Meier method and differences were assessed by the Log-rank test. Multivariate analysis was performed using the Cox proportional hazard regression model in forward stepwise regression. Receiver working characteristic curve was used to compare the accuracy of the metastatic lymph nodes ratio in predicting the death of patients 5 years postoperatively and that of metastatic lymph nodes number. RESULTS: The metastatic lymph nodes ratio didn't correlate with the total number of dissected lymph nodes, whereas metastatic lymph nodes number did. Kaplan-Meier survival analysis demonstrated the metastatic lymph nodes ratio significantly influenced the postoperative survival time and Cox proportional hazard regression model analysis showed the metastatic lymph nodes ratio was an independent poor prognostic factor. There was no significant difference between the area under the receiver working characteristic curve of metastatic lymph nodes ratio and metastatic lymph nodes number in predicting the death of patients 5 years postoperatively. CONCLUSIONS: The metastatic lymph nodes ratio in T(2)-T(3) stage gastric cancer patients is not correlated with the total number of dissected lymph nodes if at least 15 lymph nodes are dissected. The metastatic lymph nodes ratio is a major independent poor prognostic factor of the patients of T(2)-T(3) stage gastric cancer. The ability of the metastatic lymph nodes ratio in predicting the death of T(2)-T(3) stage gastric cancer patients 5 years postoperatively is the same as that of metastatic lymph nodes number.

Inhibition of the proliferation of human gastric cancer cells SGC-7901 in vitro and in vivo using Bcl-2 siRNA.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

The impact of hyperthermic chemotherapy on human gastric cancer cell lines: preliminary results.

In this preliminary study, we evaluated the impact of hyperthermia (HT) and hyperthermic chemotherapy (HTCT) on six human gastric cancer cell lines and explored the mechanisms of cell-killing effect under HTCT. Treatment conditions were categorized into 4 modes: i) normothermic control (NT), ii) HT, iii) normothermic chemotherapy (NTCT) and iv) HTCT. According to the data of MTT and LM observations, isolated HT only temporarily inhibited cell proliferation and had no cell-killing effect on gastric cancer cell lines employed in our study except for SNU-1. Combining with HT enhanced the cytotoxicity of CDDP in all gastric cell lines and the concentration inhibiting cell proliferation and inducing cell death of HTCT was much lower than that of NTCT. There was a synergistic effect of HT and chemotherapy on inhibiting proliferation in each cell line in a certain range of CDDP concentration. The data of TEM and FCM proved that HTCT induced cell death with two modes - apoptosis and necrosis, and apoptosis was the major type. Microarray illustrated that, under HTCT, a total of 58 gene expressions were regulated according to the filtering criteria, including 10 extra genes with an expression change below the threshold or even unchanged when treated with either HT or CDDP alone. Five of these 10 genes were verified by QRT-PCR. These genes may include the target genes for the enhancing effect of HT on chemotherapy and their effects should be further validated by functional analysis.

Efficacy and safety of intraoperative peritoneal hyperthermic chemotherapy for advanced gastric cancer patients with serosal invasion. A long-term follow-up study.

AIMS: This study was undertaken to investigate the clinical effects and safety of intraoperative peritoneal hyperthermic chemotherapy (IPHC) for advanced gastric cancer (AGC) patients. METHODS: A total of 118 AGC patients with serosal invasion were enrolled in this study from 1998 to 2001, 52 underwent IPHC after gastrectomy and 66 were treated with gastrectomy only. Among these cases, 96 patients without macroscopic peritoneal metastases were selected for the prophylactic study, 22 with peritoneal metastases were selected for the therapeutic study. Postoperative survival, recurrence pattern and incidences of postoperative complications between patients with and without IPHC were analyzed and compared. RESULTS: For the prophylactic study, the IPHC procedure improves postoperative survival rate and decrease the incidence of peritoneal recurrence, and is an independent prognostic factor for these patients. For the therapeutic study, postoperative survival times were longer if IPHC was undertaken. No surgery-related death occurred. The incidence of renal dysfunction was higher in the IPHC group, but all patients recovered without hemodialysis. CONCLUSION: IPHC is a safe procedure that improves the survival prognosis for AGC patients with serosal invasion. It is especially beneficial for patients without peritoneal metastasis due to the reduction of postoperative peritoneal recurrence.

[High-resolution analysis of chromosome 5 and identification of candidate genes in gastric cancer].

OBJECTIVE: To explore the relationship between loss of heterozygosity (LOH) of 5p with the histological phenotype in gastric cancer. METHODS: Eighty pairs of tumor and adjacent normal mucosa samples were collected and genomic DNA was extracted. Total of 17 polymorphic microsatellite markers for 5p were used for LOH analysis. A part of samples were fixed in 10% buffered formalin and stained with H&E. Histological type of gastric cancer was defined according to Lauren's classification. RESULTS: The average informative rate of all seventeen markers was 60.0%. The LOH at least in one locus was detected in 28 of the 80 (35.0%) cases. The highest LOH frequency occurring at D5S2849 (7.77 cM), with LOH frequency of 35.2% (19/54). The minimal LOH region was spanned from 6.67 to 9.41 cM (1.18 Mb, covering 2.7 cM), including D5S417, D5S2849, D5S1492 and D5S2088. In 28 with LOH, 24 (85.7%) cases were of intestinal type, and only 4 cases (14.3%) were of diffuse type. There is significant difference between LOH frequency in intestinal-type and diffuse-type gastric cancers (P < 0.01). Searching the NCBI database disclosed that this minimal deletion region at 5p15.33 covered 3 candidate genes, IRX1, IRX2, and CEI. CONCLUSION: The molecular events in 5p 15.33 may be related with the morphological differentiation and development of gastric cancer. Gastric cancer with LOH of 5p15.33 locus tends to develop in to intestinal type. The cluster of candidate genes in 5p15.33 may be closely implicated in carcinogenesis of intestinal type gastric carcinoma.

[Gene expression profiling of diffuse-type gastric cancer by cDNA microarray].

OBJECTIVE: To identify cancer-related genes in diffuse-type gastric cancer and to explore its molecular mechanism by cDNA microarray analysis. METHODS: A total of 22 pairs of diffuse-type gastric cancer tissue and the corresponding normal mucosa were taken and freshly frozen. cDNA microarray with 14,592 genes/ESTs was used. Genes were considered to be up- or down-regulated when the fluorescent intensity ratio between tumor and normal mucosa was over 2-fold in over 50% of the samples (P < 0.05). Hierarchical clustering of regulated genes was performed as a measure to study expressional similarity. Validation of array results was carried out by real time quantitative PCR (QPCR). RESULTS: Compared with those of corresponding normal mucosa, there were a total of 153 genes/ESTs up-regulated and 204 down-regulated in diffuse-type gastric cancer. Hierarchical clustering demonstrated that the genes belonging to the same subgroup displayed similar function. Most of the overexpressed genes were those related to cell adhesion, cell motility, matrix reconstruction, cell proliferation and/or signal transduction; while genes related to defense response, toxicoid metabolism, DNA repairing, nuclear-cytoplasmic transport and/or anti-apoptosis made up the main list of the underexpressed genes. Seven genes showed higher expression in TNM (T I + T II) group than in (T III + T IV) group. QPCR confirmed the array analysis results. CONCLUSION: Gene expression profiling by cDNA microarray analysis provides not only molecular understanding of biological properties of cancer, but may also be helpful in discovering new diagnostic markers and therapeutic targets in gastric adenocarcinoma.

[Identification of biomarkers in the serum of the patients with poorly differentiated gastric cancer].

OBJECTIVE: To investigate the application of proteomics in the field of serology,and to screen the differential expression proteins related with poorly differentiated gastric carcinoma. METHODS: Two-dimensional electrophoresis (2-DE) was applied to segregate the total proteins in the serum form gastric cancer patients and health volunteers. After staining,the differential expression proteins were analyzed using PDQuest software,and identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). RESULTS: Electrophoresis figures with high resolution and reproducibility were obtained. Six differential expression proteins were found only in the serum from gastric cancer patients, while four other proteins from healthy volunteers. CONCLUSIONS: Protein expression is differential in the serum from the gastric cancer patients and health volunteers. It is hopeful to find the biomarkers related with poorly differentiated gastric carcinoma using proteomics.

[The relationship between frameshift mutations of transforming growth factor-beta type II receptor, insulin growth factor II receptor, bcl-2 associated X protein, E2F4 and microsatellite instability in gastric carcinoma].

OBJECTIVE: To determine the microsatellite instability in gastric carcinomas, examine the frameshift mutations of transforming growth factor-beta type II receptor (TGFbetaRII), insulin growth factor II receptor (IGFIIR), bcl-2 associated X protein (BAX) and E2F4, and investigate whether or how alterations of the TGFbetaRII, IGFIIR, BAX and E2F4 gene are associated with MSI in gastric cancer. METHODS: Formalin-fixed, paraffin-embedded gastrectomy specimens and matching normal tissues of 65 cases of gastric carcinomas were retrieved from shanghai Ruijin Hospital and Shanghai East Hospital. DNA was extracted from tissue sections using phenol chloral isoamyl alcohol. Sections with no more than 50% of tumor cell areas were isolated by microdissection. DNA was amplified by PCR-based single strand conformation polymorphism (SSCP) for microsatellite analysis and was sequenced directly. Frameshift mutations in the coding regions, repetitive mononucleotide tracts of (A)10 for TGFbetaRII, (G)8 for IGFIIR, (G)8 for BAX, and trinucleotide repeats of (AGC)13 for transcription factors E2F4 were detected using PCR. Tumors were classified as being microsatellite stable (MSS) or having a low frequency of MSI (MSI-L, one of markers different in the tumor) or a high frequency of MSI (MSI-H, two or more of markers different). RESULTS: Eleven cases (18.0%) showed MSI-L, 12 (19.7%) showed MSI-H and 38 (62.3%) cases showed MSS. The mutation rates of TGFbetaRII, IGFIIR, BAX and E2F4 gene were 19.7%, 4.9%, 6.6% and 16.4% respectively. Among the 12 MSI-H gastric cancers, there were 10 TGFbetaRII mutations, 3 IGFIIR mutations, 4 BAX mutations and 10 E2F4 gene mutations. The alterations in the repeats of the related genes presented polymorphisms. Associations of MSI-H status and mutations of the 4 genes were highly significant (P < 0.01, respectively). No repeat tracts mutations in TGFbetaRII, IGFIIR, BAX and E2F4 gene were found in MSS tumors. CONCLUSIONS: The repeat coding regions within TGFbetaRII, IGFIIR, BAX and E2F4 gene are the targets of microsatellite instability. Frameshift mutations of the 4 genes play an important role in the development and progression of gastric cancers with microsatellite instability.

[Fusion expression of gastric cancer-related gene MPS-1 and preparation of rabbit antibody against GST-MPS-1].

AIM: To express the fusion protein GST-MPS-1 in E.coli and prepare rabbit antibody against GST-MPS-1. METHODS: MPS-1 cDNA was inserted into the vector of pGEX-5X. The recombinant was then transformed into E.coli BL21. After induction with the IPTG, the fusion protein GST-MPS-1 was expressed in E.coli. The purified fusion protein was then used to immunize the New Zealand rabbits to obtain the polyclonal antibody against GST-MPS-1. Specificity of the antibody was tested by Western blot and immunofluorescent staining. RESULTS: The cDNA sequence of MPS-1 in the recombinant was confirmed by restriction endonuclease digestion and sequence analysis. SDS-PAGE result showed that fusion protein was highly expressed in E.coli with a molecular weight of 36 kDa. The titer of the rabbit serum against GST-MPS-1 was as high as 1x10(5) in ELISA analysis. The polyclonal antibody were found to specifically bind to MPS-1 protein in Western blot and immunofluorescent staining. CONCLUSION: The preparation of the polyclonal antibody against MPS-1 lay a foundation for the further study of MPS-1 expression at protein levels and its function.

[Clinical effect of intraoperative peritoneal hyperthermic chemotherapy for advanced gastric cancer].

OBJECTIVE: To investigate the clinical effect of intraoperative peritoneal hyperthermic chemotherapy (IPHC) for advanced gastric cancer (AGC). METHODS: A total of 118 AGC patients with serosal invasion were enrolled in this study from 1998 to 2001. Among these cases, 96 patients without macroscopic peritoneal metastases were selected for prophylactic study, including 42 cases with IPHC and 54 cases without IPHC as control. Other 22 patients with macroscopic peritoneal metastases were selected for therapeutic study, including 10 cases with IPHC and 12 without IPHC. Postoperative survival rate and peritoneal recurrence were compared. RESULTS: For prophylactic study, the 1, 2 and 4 years survival rates were 85.7%, 81.0% and 63.9% respectively in the patients with IPHC,significantly higher than 77.3%, 61.0% and 50.8% in the patients without IPHC. Cox ratio hazard model revealed that IPHC procedure was an independent prognostic factor. More patients in the control group suffered from peritoneal recurrence than those in IPHC group (34.7% vs 10.3%). For therapeutic study,the median survival period of the patients with IPHC was 10 months, higher than 5 months in the patients without IPHC. The overall 1, 2, 4 year survival rates were 76.9%, 69.2%, 55.2% respectively in all cases with IPHC, higher than 66.2%, 49.7%, 41.4% in the cases without IPHC. CONCLUSION: IPHC procedure can improve the prognosis of AGC patients with serosal invasion, reduce the risk for peritoneal recurrence, and is an independent prognostic factor.

[Expression and clinical significance of cancer-related gene MPS-1 in gastric cancer].

OBJECTIVE: To investigate the expression of cancer-related gene MPS-1 in gastric cancer and to evaluate its significance in clinical diagnosis and therapy. METHODS: The mRNA expression of MPS-1 was determined by polymerase chain reaction after reverse transcription (RT-PCR) in cancer tissues and adjacent non-cancerous tissues from 42 cases with gastric cancer. The expression levels of MPS-1 in 6 gastric cancer cell lines (AGS, MKN-45, SGC 7901, KATO III, N-87 and SNU-1) were also determined by RT-PCR and Western blot. RESULTS: The MPS-1 mRNA was expressed in all tissues and cell lines. The mRNA expression level of MPS-1 in cancer tissues were 1.37+/- 0.87, significantly higher than 0.99+/- 0.67 in adjacent normal gastric mucous tissues (P< 0.01). The expression of MPS-1 was correlated with TNM stage (P< 0.05), but not with age, gender, tumor size and differentiation. The expression level of MPS-1 mRNA in the primary lesions was hig her in the patients with TNM stages III, IV than those with TNM stages I, II. Meanwhile, RT-PCR and Western blot showed the same results that MPS-1 expression was higher in the six gastric cancer cell lines as compared with that in the normal gastric cell line GES-1. CONCLUSION: The high expression of MPS-1 in gastric cancer indicates that MPS-1 might play an important role in gastric carcinogenesis,which may provide a new target in immunotherapy for gastric cancer.

[Inhibitory effect of dendritic cells pulsed with MAGE-3 peptide on transplanted murine gastric cancer in mice].

OBJECTIVE: To observe the inhibitory effect of MAGE-3 peptide pulsed DC on transplanted murine gastric cancer in 615 mice. METHODS: The CTL clones directed against MAGE-3 peptide were tested for the ability to lyse the gastric cancer cell line MFC which can express MAGE-3 antigen. In immunoprotection experiment, mice of the study group were immunized with MAGE-3 peptide pulsed DC (DC/MAGE-3) at the dosage of 1 x 10(6) on d0 and d7 by sc inoculation, mice of control groups were immunized with influenza virus peptide pulsed DC (DC/Nup) or unpulsed DC at the same dosage on days as the DC/MAGE-3 group. On d14, all the mice were challenged with sc injections of 5 x 10(5) MFC gastric cancer cells. In immunotherapy experiment, all the mice were sc injected 5 x 10(5) MFC gastric cancer cells on d0, and on d3, d10 mice of each groups were sc inoculated with DC/MAGE-3, DC/Nup or unpulsed DC at the dosage of 1 x 10(6) respectively. All mice were monitored closely with respect to tumor growth and survival times. RESULTS: The CTL clone induce by MAGE-3 peptide could lyse the MFC cells efficiently. Immunization of mice with DC pulsed with MAGE-3 generated partial protective immunity against MFC tumor, as well as significant inhibition of tumor growth in a 3-day tumor model. CONCLUSION: The tumor vaccine with DCs pulsed with MAGE-3 peptide possesses the ability to stimulate tumor specific CTL activity and to establish antitumor immunity when administered in vivo.

[Relationship between urokinase-type plasminogen activator expression and peritoneal metastatic potency in different gastric cancer cell lines].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: The uPA expression and activity are significantly different among 4 gastric cancer cell lines, and positively correlated with their peritoneal metastatic potency.

[COX- 2 expression in gastric cancer and its relationship with lymphangiogenesis and lymph node metastasis].

OBJECTIVE: To investigate the expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-C (VEGF-C) in human gastric cancer, the relationship between their expression and the clinicopathological features,as well as the relationship between these two parameter expression and lymphangiogenesis and lymph node metastasis. METHODS: COX-2 and VEGF-C expressions were detected in 63 gastric cancer samples by immunostaining. Lymphangiogenesis was evaluated by immunostaining with the specific antibody LYVE-1. RESULTS: The expression rates of COX-2 and VEGF-C were 66.7% (42/63), 52.4% (33/63), respectively in 63 gastric cancer specimens. LYVE-1 was positive in 35 cases (35/63), which indicated lymphangiogenesis in the tumors. The expression of COX-2 was significantly correlated with the expression of VEGF-C, tumor lymphangiogenesis and lymphatic metastasis (P< 0.05), however not gender, tumor size, tumor location, Lauren classification and serosa invasion (P< 0.05). CONCLUSIONS: In gastric cancer, the expression of COX-2 is significantly associated with VEGF-C expression, lymphangiogenesis and lymphatic metastasis. COX-2 may up-regulate the expression of VEGF-C, which induces lymphangiogenesis and accordingly contributes to lymphatic metastasis.