Gastric Carcinoma In Nude Mice Research Articles

Low dose irradiation increases adoptive cytotoxic T lymphocyte migration in gastric cancer.

Adoptive cellular immunotherapy (ACI) has been demonstrated to be a promising cancer therapeutic; however, the inefficient migration of adoptive immune cells to tumors is one of the rate-limiting factors of ACI. The present study investigated whether 2 Gy low dose irradiation (LDI) was able to increase the migration of adoptive lymphocytes to gastric cancer cells. Treatment with 2 Gy LDI resulted in marked chemokine (C-X-C motif) ligand 9 (CXCL9) and CXCL10 production from gastric cancer cell lines. A Transwell chamber migration assay demonstrated enhanced transmigration of cytotoxic T lymphocytes to gastric cancer cells following LDI treatment. After 2 Gy LDI application to established gastric carcinoma in nude mice, labeled immune cells were infused by intravenous injection and concentrated fluorescence signals were observed at the tumor sites within the mice, with a peak signal at 8-h LDI. Increased numbers of adoptive T cells at the tumor sites were also observed using flow cytometry. Furthermore, a case study of a patient with metastatic gastric cancer who had received ACI treatment combined with 2 Gy LDI provided further evidence that 2 Gy LDI is able to recruit antitumor effector T cells to tumor sites. Therefore, the ability of 2 Gy LDI to convert tumors into inflamed peripheral tissues may be exploited to overcome obstacles at the effector phase of the antitumor immune response and improve the therapeutic efficacy of immunotherapy.

The effect of EGB on proliferation of gastric carcinoma SGC7901 cells.

To investigate the effect of Ginkgo biloba extract (EGB) on the proliferation and cell cycles of gastric carcinoma SGC7901 cells, and make a preliminary exploration on possible molecular mechanisms associated with its inhibitory effect. Human gastric carcinoma SGC7901 cells were cultured in vitro, and treated with various concentrations (100, 200, 300, 400 mg/L) of EGB for different incubation periods (24, 48 and 72 h). CCK-8 assay was used to detect cell proliferation and flow cytometry was performed to analyze the effect of EGB on cell cycles. In addition, mRNA and protein level of two cell cycle regulators cyclin D1 and c-myc in SGC7901 cells treated with EGB were determined using PCR and Western blot. And subcutaneous xenograft model of gastric carcinoma in nude mice was established to evaluate the anti-cancer effect of EGB in vivo. The proliferation of gastric carcinoma SGC7901 cells was inhibited by EGB in dose- and time-dependent manner. Flow cytometry showed cell cycle arrest in EGB-treated cells, with increased percentage of cells in G1 phase and decreased percentage in S stage. In addition, the mRNA and protein level of cyclin D1 and c-myc genes were significantly down-regulated in cells with EGB treatment with the concentration increasing. EGB conferred an inhibitory effect on the proliferation of gastric carcinoma SGC7901 cells both in vitro and in vivo. The inhibitory effect was dose dependent and possibly depended on inhibiting cell cycle through G1 arrest induction by suppressing cyclin D1 and c-myc expression.

Quantitative analysis of contrast-enhanced ultrasound in the evaluation of YC-1 effect

Objective To explore the value of contrast-enhanced ultrasound quantitative analysis in the evaluation of YC-1 effect on transplanted tumor of human gastric carcinoma in nude mice.Methods The transplanted tumor model of human gastric carcinoma in nude mice was established by injecting SGC7901/displatin (DDP) cells into the subcutaneous space of 24 nude mice.The mice were randomized into four groups as control group ( DMSO given),DDP group ( DDP given),YC-1 group (YC-1 given) and YC-1 + DDP group ( both YC-1 and DDP given).Contrast-enhanced ultrasound was performed one week after withdrawl and the dynamic image was analyzed quantitatively using SonoLiver software.For each tumor,two ROIs as ROItotal (including the total tumor) and ROIsmall (including the highest enhanced part of the tumor)were drawn and parameters including time-to-peak (TTP),rise time (RT),mean transit time (mTT),maximun intensity ( Imax),R10,R20 and R30 ( descending velocity-the rate of intensity at TTP + 10/20/30 s to Imax) and ascending velocity (Vasc) were recorded for the statistical analysis.Results No parameter had significant difference between control group and DDP group or between YC-1 group and YC-1 + DDP group in both ROIsamll and ROItotal (P ＞ 0.05 ).The mice were regrouped into YC-1-treated-group and non-YC-1-treated-group.For ROItotal,no parameter had significant difference between the two groups (P ＞ 0.05 ).For ROIsmall,microbubbles in YC-1-treated-group reached the peak earlier (TTP:5.47 ±0.93 vs 8.05 ±2.00; RT:4.99 ±0.96 vs 7.67 ± 1.78,P＜0.05) and regressed faster (mTT:37.49 ± 19.51 vs 98.94 ±60.97; R10:0.39 ±0.15 vs 0.55 ±0.08; R20:0.30 ±0.10 vs 0.43 ±0.10; R30:0.25 ±0.08 vs0.33±0.08) than in non-YC-1-treated-group (P＜0.05).Conclusion Contrast-enhanced ultrasound quantitative analysis could reflect the change of tumor blood supply after antiangiogenesis treatment.ROIsmall was more suitable and sensitive than ROItotal to evaluate antiangiogenesis effect. Key words: Ultrasonography ; Contrast media; Neovascularization

Effect of silencing heparanase on the biological behavior of gastric carcinoma in nude mice

To investigate the effects of silencing heparanase (HPA) on growth, angiogenesis and metastasis of human gastric carcinoma transplanted in nude mice. Human gastric carcinoma SGC-7901 cells and those cells with silenced HPA (gastric carcinoma SGC-7901-HPA(-)) were separately transplanted subcutaneously in 6 nude mice. The time, size and speed of tumor growth were recorded. RT-PCR and Western-blot were used to detect the expression of HPA mRNA and protein in the subcutaneous tumors of the two groups. Immunohistochemical staining was used to detect microvessel density (MVD) in the subcutaneous tumors of the two groups. Cells of the subcutaneous transplanted tumors of the two groups were separately injected into the peritoneal cavity of nude mice, 6 mice each. The growth of metastatic tumors in nude mice was observed. Human gastric carcinoma SGC-7901 cells and SGC-7901-HPA(-) cells were subcutaneously inoculated in nude mice, and tumors appeared at 4 days and 7 days after inoculation, respectively. The MVD was (20.69 ± 1.20)/HP and (11.35 ± 1.94)/HP, respectively (P < 0.05). The expressions of HPA mRNA and protein of the subcutaneously transplanted SGC-7901-HPA(-) tumor were decreased. Four voluminous metastatic tumors caused by SGC-7901 cells occurred in 3 mice in the liver, right kidney, omentum and intestine. Two smaller abdominal metastatic tumors of SGC-7901-HPA(-) cells were found in the liver and right kidney. Silencing HPA can inhibit the tumor growth, angiogenesis and metastasis of human gastric cancer in nude mice. It suggests that HPA might become a new target for prevention and treatment of gastric cancer.

Establishment of an alpha-fetoprotein-producing human gastric carcinoma in nude mice.

An alpha-fetoprotein (AFP)-producing human gastric carcinoma was transplanted into BALB/c-nu/nu nude mice. The original tumor tissue had been obtained by gastrectomy from a 72-year-old patient with gastric carcinoma. The tumor had been transplanted serially (20 passages) in nude mice. The transplantability was 100%. The doubling time of the tumor ranged from 5.6 days to 11.2 days. AFP appeared in the serum of nude mice 3 to 4 weeks after subcutaneous (sc) transplantation and 6 weeks after intraperitoneal (ip) transplantation of the tumor cell suspension prepared from sc transplanted tumors. A positive correlation was observed between serum AFP level and tumor size. Serum AFP level of mice given ip transplantation increased as a function of time after transplantation. AFP was stained positively by an immunochemical technique in the original and transplanted tumors and was located in the cytoplasms of the tumor cells. The histology of the original tumor was retained. The malignant potential of these transplanted tumor cells was expressed as carcinomatous peritonitis and liver and/or lung metastases.

Wogonin suppresses tumor growth in vivo and VEGF-induced angiogenesis through inhibiting tyrosine phosphorylation of VEGFR2

Previous studies revealed that wogonin, a naturally occurring monoflavonoid extracted from Scutellariae radix, possessed anticancer activity both in vitro and in vivo. However, the molecular mechanism of its potent anticancer activity remains poorly understood and warrants further investigations. In this study, we found for the first time that wogonin inhibited the growth and tumor angiogenesis of human gastric carcinoma in nude mice. We explored the inhibitory effect of wogonin on angiogenesis stimulated by vascular endothelial growth factor (VEGF) in vitro. Wogonin suppressed the VEGF-stimulated migration and tube formation of human umbilical vein endothelial cells (HUVECs). It also restrained VEGF-induced tyrosine phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2). This inhibition of receptor phosphorylation was correlated with a significant decrease in VEGF-triggered phosphorylated forms of ERK, AKT and p38. Taken together, these findings strongly suggest that wogonin might be a promising antitumor drug.

Orthotopic Models of Human Gastric Carcinoma in Nude Mice: Applications for Study of Tumor Growth and Progression

Gastric carcinoma (GC) remains a leading cause of cancer related deaths worldwide with the 5-year survival rate in the U.S. at -5% to 15% with existing therapies. This tumor is aggressive and has often metastasized to distant sites (liver, lung, and adjacent intestine) by the time of diagnosis. Treatment options (surgery, radiation, and chemotherapy) are limited and the disease carries a grave prognosis for most patients (50% 5-year survival for distal GC; 10% 5-year survival for proximal GC). An orthotopic model of human GC in nude mice provides an excellent way to evaluate the pathogenesis of tumor growth and metastasis in order to develop effective therapies, as well as to better understand the underlying biology of gastric tumor growth and metastasis. The protocol described in this unit details the development and characterization of an orthotopic model of human GC in athymic nude mice with diffuse lymphatic and hepatic metastatic spread. This model closely mimics the course of the human disease.

Monocyte Chemoattractant Protein-1 Transfection Induces Angiogenesis and Tumorigenesis of Gastric Carcinoma in Nude Mice via Macrophage Recruitment

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that has various roles in tumor development and progression. We previously reported that expression of MCP-1 is associated with macrophage infiltration and tumor vessel density in human gastric carcinomas. The present study was undertaken to obtain direct evidence that MCP-1 participates in recruitment of macrophages and induction of angiogenesis. We did transfection experiments to analyze the role of MCP-1 in tumorigenicity and angiogenesis in gastric carcinoma in nude mice. The human MCP-1 gene cloned into the BCMGS-Neo expression vector was transfected into the human gastric carcinoma TMK-1 cell line. We examined tumor volumes with the ectopic s.c. xenograft model and tumorigenicity with the orthotopic gastric xenograft model. We determined intratumor microvessel counts and tumor-infiltrating macrophage counts by immunohistochemical staining. There was no difference in in vitro proliferation between MCP-1-transfected TMK-1 cells and mock-transfected (control) cells; however, MCP-1 transfectants induced tumor growth in ectopic xenografts and increased tumorigenicity and induced lymph node metastases and ascites in orthotopic xenografts. In both ectopic and orthotopic xenograft models, strong infiltration of macrophages was observed within and around the tumors after implantation of MCP-1 transfectants whereas fewer macrophages were seen after inoculation of control cells. The microvessel density was significantly higher in tumors produced by MCP-1 transfectants than in control tumors. MCP-1 produced by gastric carcinoma cells may regulate angiogenesis via macrophage recruitment. MCP-1 may be a potential target for antiangiogenic therapy for gastric carcinoma.

Preparation of magnetic polybutylcyanoacrylate nanospheres encapsulated with aclacinomycin A and its effect on gastric tumor.

To evaluate the effect of aclacinomycin A-loaded magnetic polybutylcyanoacrylate nanoparticles on gastric tumor growth in vivo and in vitro. Magnetic polybutylcyanoacrylate (PBCA) nanospheres encapsulated with aclacinomycin A (MPNS-ACM) were prepared by interfacial polymerization. Particle size, shape and drug content were examined. Female BABL/c nude mice were implanted with MKN-45 gastric carcinoma tissues subcutaneously to establish human gastric carcinoma model. The mice were randomly divided into 5 groups of 6 each: ACM group (8 mg/kg bm); group of high dosage of MPNS-ACM (8 mg/kg bm); group of low dosage of MPNS-ACM (1.6 mg/kg bm); group of magnetic PBCA nanosphere (MPNS) and control group (normal saline). Magnets (2.5 T) were implanted into the tumor masses in all of the mice one day before the therapy. Above-mentioned drugs were administered intravenously to the mice of every group on the first day and sixth day. When the mice were sacrificed, tumor weight was measured, and the assay of granulocyte- macrophage colony forming-unit (CFU-GM) was performed on semi-solid culture. White blood cell, alanine aminotransferase and creatine were examined. 3-(4-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to examine the viability of MKN-45 cells after incubation with different concentrations of ACM, MPNS and MPNS-ACM suspension respectively for 48 h. Content of ACM in MPNS-ACM was 12.0% and the average diameter of the particles was 210 nm. The inhibitory rates of ACM (8 mg/kg bm), high dosage of MPNS-ACM (8 mg/kg bm), low dosage of MPNS-ACM (1.6 mg/kg bm) and MPNS on human gastric carcinoma in nude mice were 22.63%, 52.55%, 30.66% and 10.22%, respectively. There was a significant decrease in the number of CFU-GM of bone marrow in ACM group compared with control group, whereas no obvious change was observed in that of the nanosphere groups. The values of 50% inhibition concentration (IC50) of ACM, MPNS and MPNS-ACM were 0.09, 97.78 and 1.07 microg/mL, respectively. The tumor inhibitory rate of MPNS-ACM was much higher than that of ACM under magnetic field and the inhibition on bone marrow was alleviated significantly compared with ACM group.

Matrix metalloproteinase inhibitor, marimastat, decreases peritoneal spread of gastric carcinoma in nude mice.

Marimastat, a matrix metalloproteinese inhibitor, was examined for the ability to prevent peritoneal dissemination of a human gastric cancer xenograft, TMK–1. Even with novel approaches such as molecular targeting of cancer chemotherapy, peritoneal dissemination of gastric cancer has little sensitivity to anticancer drugs, and it is impossible to inhibit its growth completely. Intraperitoneal injection of TMK–1 into nude mice at 5 × 105 cells/body resulted in carcinomatous peritonitis that mimicked clinical cases. Continuous administration of marimastat (18 mg/kg/day) from 24 h after the tumor inoculation successfully inhibited the growth of peritoneal dissemination nodules. Combined administration of marimastat (18 mg/kg/day) and mitomycin C (MMC, 2 mg/kg) showed synergistic inhibition of growth of peritoneal dissemination, being superior to MMC alone (2 mg/kg). Although marimastat alone could not increase survival tune with statistical significance, combined administration of marimastat and MMC had a survival benefit with statistical significance. The combination of marimastat and MMC increased the preventive effect on peritoneal dissemination. Marimastat seems to be a candidate for the prevention of peritoneal spread of gastric carcinoma.

Establishment of a human chorionic gonadotropin‐producing human gastric carcinoma in nude mice

A human chorionic gonadotropin (HCG)-producing gastric carcinoma was transplanted into BALB/c nu/nu nude mice. The original tumor tissue had been obtained by gastrectomy from a 55-year-old patient with gastric carcinoma. The tumor was transplanted serially in nude mice, and its doubling time was stable to approximately 12 days. A positive correlation was observed between serum HCG level and tumor weight. The serum HCG level of the mice and the histology of the tumor weight. The serum HCG level of the mice and the histology of the tumor, papillary adenocarcinoma with partial poorly differentiated adenocarcinoma, did not change on serial transfers. HCG was positively stained by an immunochemical technique only in the site of the poorly differentiated adenocarcinoma, while staining was negative in the site of the papillary adenocarcinoma, which constituted most of the tumor. These results indicate that this tumor in nude mice will be useful not only as a therapeutic experimental system but also for studying the potential malignancy of HCG-producing cancer cells.

Establishment and characterization of a new spontaneous metastasis model of human gastric carcinoma in nude mice.

A poorly differentiated medullary carcinoma of human stomach, designated HY–1, was successfully transplanted to nude mice by either the subcutaneous or intramuscular route for five generations. The transplanted tumor showed spontaneous lung metastases in nearly 100% of KSN and Balb/c female nude mice. There were over 20 visible lung metastatic nodules in KSN and Balb/c nude mice bearing tumors for over SO days. Immunostaining of type IV collagen and electron microscopy revealed that tumor cells were often in direct contact with basement membrane (BM) of tumor blood vessels in the primary tumor tissue. At the site of contact between tumor cells and vascular BM, focal disappearance of the BM, disruption of endothelial cells and entry of tumor cell clusters into vascular lumen were observed. Immunostaining of 72 kDa gelatinase/type IV collagenase demonstrated that tumor cells expressed this enzyme in their cytoplasm. These results suggest that spontaneous metastasis of this tumor may be partly due to a marked tendency to vascular invasion involving the following sequential events: tumor cell contact with vascular BM, BM degradation possibly by 72 kDa gelatinases and endothelial disruption. This model could be a useful tool for understanding the mechanism of hematogenous metastasis of human gastric cancer.