Orthotopic transplantation model of human gastrointestinal cancer and detection of micrometastases

AIM: To establish a relevant animal model of human gastrointestinal cancer, which can be used for repetitive investigations, so as to improve our understanding and management of carcinogenesis and cancer metastasis. METHODS: Intact tissues of human colorectal and pancreatic cancers were transplanted in nude mice. The biological characteristics of the original and the corresponding transplanted tumors were investigated by HE staining, PAS staining and immunostaining. The metastases in the livers and lungs of nude mice were investigated by immunostaining with biotinylated mab KL-1 and by RT-PCR using CK20 specific primers. RESULTS: There were totally 9 of 16 surgical specimens growing in nude mice subcutaneously and/or orthotopically (4 of 6 colorectal and 5 of 10 pancreatic cancer). Tumor cell content of the specimens and freezing of tissue specimens are important factors influencing the growth of transplanted tumor. In the group of fresh tumor tissues with greater than 50% tumor cell content, the success rate of the transplantation was 100% (3 cases of pancreatic cancer and 3 cases of colorectal cancer). The orthotopically trans-planted tumors resemble the original tumor morphologically and biologically, including TAA expression such as CEA by immunohistochemistry, and CEA level in the serum of mice. Ki-67 labeling index and the expression of TAA especially K-ras, 17-1A and RA-96, are associated with the potential of tumor growth in nude mice. Micrometastases in the lungs and livers of tumor bearing mice can be detected by immunostaining with biotinylated mab KL-1 and CK20-specific RT-PCR. CONCLUSION: An orthotopic transplantation model for human colon and pancreatic cancer in nude mice has been set up. We have also established sensitive detection methods with CK-immunohistochemistry and CK20-RT-PCR to study xenotransplanted human cancer and its metastatic cancer cells in the liver and lung of nude mice. This study may be helpful in understanding the mechanism of cancer metastasis and in developing new diagnostic methods and therapeutic strategies for metastases including micrometastases.

Effects of epidermal growth factor on the growth of human gastric cancer cell and the implanted tumor of nude mice

AIM: Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has been established that the EGF can promote gastric cytoprotection and ulcer healing. But the potential ability of EGF to regulate the gastric cancer growth is unknown. This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice. METHODS: The cell growth rates of human gastric adenocarcinoma cell lines MKN-28, MKN-45, SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF (rhEGF, 0.05, 0.1, 0.5, 1.0, 10, 50, 100 mg.L(-1)) using MTT method. The cells of MKN-28, MKN-45, SGC-7901 (gastric cancer tissue 1.5mm(3)) were implanted in the BALB/cA nude mice for 10 days.The EGF was given intraperitoneally (15, 30, 60 microg.kg(-1)) for 3 weeks. The body weights of the tumor-bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice. RESULTS: Within the concentration range of 0.05-100mg.L(-1), rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100% vs 102.8%, P【0.05), but partially restrain the gastric cancer cell growth. The latter effect was related to cell differentiation. In 15-60 microg/kg rhEGF groups, the mean implanted tumor mass of MKN-28 cell were 1.75 g, 1.91 g, 2.08 g/NS group 1.97 g (P】0.05), the mean tumor mass of SGC-7901 cell were 1.53 g, 1.07 g, 1.20 g/NS group 1.07 g (P】0.05), and for MKN-45 cell, the tumor mass were respectively 1.92 g, 1.29 g, 1.77 /NS group 1.82 g (P】0.05). So rhEGF had no obvious effect on implanted MKN-28, SGC-7901 and MKN-45 tumor growth. CONCLUSION: EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.

Antitumor activities of human autologous cytokineinduced killer(CIK)cells against hepatocellular carcinoma cells in vitro and in vivo

AIM: To characterize the anticancer function of cytokine-induced killer cells (CIK) and develop an adoptive immunotherapy for the patients with primary hepatocellular carcinoma (HCC), we evaluated the proliferation rate, phenotype and the antitumor activity of human CIK cells from healthy donors and HCC patients in vitro and in vivo. METHODS: Peripheral blood mononuclear cells (PBMC) from healthy donors and patients with primary HCC were incubated in vitro and induced into CIK cells in the presence of various cytokines such as interferon-gamma (IFN-gamma), interleukin-1 (IL-1), IL-2 and monoclonal antibody (mAb) against CD3. The phenotype and characterization of CIK cells were identified by flow cytometric analysis. The cytotoxicity of CIK cells was determined by (51)Cr release assay. RESULTS: The CIK cells were shown to be a heterogeneous population with different cellular phenotypes. The percentage of CD3+/CD56+ positive cells, the dominant effector cells, in total CIK cells from healthy donors and HCC patients, significantly increased from 0.1-0.13% at day 0 to 19.0-20.5% at day 21 incubation, which suggested that the CD3+ CD56+ positive cells proliferated faster than other cell populations of CIK cells in the protocol used in this study. After 28 day in vitro incubation, the CIK cells from patients with HCC and healthy donors increased by more than 300-fold and 500-fold in proliferation cell number, respectively. CIK cells originated from HCC patients possessed a higher in vitro antitumor cytotoxic activity on autologous HCC cells than the autologous lymphokine-activated killer (LAK) cells and PBMC cells. In in vivo animal experiment, CIK cells had stronger effects on the inhibition of tumor growth in Balb/c nude mice bearing BEL-7402-producing tumor than LAK cells (mean inhibitory rate, 84.7% vs 52.8%, P【0.05) or PBMC (mean inhibitory rate, 84.7% vs 37.1%, P【0.01). CONCLUSION: Autologous CIK cells are of highly efficient cytotoxic effector cells against primary hepatocellular carcinoma cells and might serve as an alternative adoptive therapeutic strategy for HCC patients.

Antihepatoma effect of alpha-fetoprotein antisense phosphorothioate oligodeoxyribonucleotides in vitro and in mice

AIM: To evaluate antihepatoma effect of antisense phosphorothioate oligodeoxyribonucleotides (S-ODNs) targeted to alpha-fetoprotein (AFP) genes in vitro and in nude mice. METHODS: AFP gene expression was examined by immunocytochemical method or enzyme-linked immunosorbent assay. Effect of S-ODNs on SMMC-7721 human hepatoma cell growth in vitro was determined using microculture tetrazolium assay. In vitro antitumor activities of S-ODNs were monitored by measuring tumor weight differences in treated and control mice bearing SMMC-7721 xenografts. Induction of cell apoptosis was evaluated by fluorescence-activated cell sorter (FACS) analysis. RESULTS: Antisense S-ODN treatment led to reduced AFP gene expression. Specific antisense S-ODNs, but not control S-ODNs, inhibited the growth of hepatoma cells in vitro. In vitro, only antisense S-ODNs exhibited obvious antitumor activities. FACS analysis revealed that the growth inhibition by antisense S-ODNs was associated with their cell apoptosis induction. CONCLUSION: Antisense S-ODNs targeted to AFP genes inhibit the growth of human hepatoma cells and solid hepatoma, which is related to their cell apoptosis induction.

Changes in brain-derived neurotrophic factor expression after transplanting microencapsulated sciatic nerve cells of rabbits into injured spinal cord of rats

Changes of brain-derived neurotrophic factor （BDNF） expression reflect function of nerve cells; meanwhile, they play a significant role in researching interventions on plerosis of nerve injury. OBJECTIVE： To observe and compare the effects on changes of BDNF expression in rats with spinal cord injury between microencapsulated sciatic nerve cells of rabbits and only transplanting sciatic nerve cells of rabbits. DESIGN： Randomized controlled animal study. SETTING： Medical School of Jiujiang College. MATERIALS： The experiment was carried out in the Medical Science Researching Center, Jiujiang College from May 2004 to May 2006. A total of 90 healthy adult SD rats, weighing 250 - 300 g, of either gender; and 10 rabbits, weighing 2.0 - 2.5 kg, of either gender, were provided by Jiangxi Experimental Animal Center. METHODS： Sciatic nerve tissue of rabbits was separated to make cell suspension, After centrifugation, suspension was mixed with 15 g/L alginate saline solution and ejaculated to 20 mmol/L barium chloride saline solution by double-cavity ejaculator. The obtained cell microcapsules were suspended in saline. Rats were randomly divided into microencapsulated group, only suspension group, and only injured group with 30 animals in each group. After anesthesia, T10 spinous process and vertebra lamina of rats in the former two groups were exposed. Spinal cord tissue in 2-mm length was removed from rats by spinal cord right hemi-section. The gelatin sponges with the size of 2 mm × 2 mm × 2 mm were grafted as filing cage, and absorbed 10 μL microencapsulated sciatic nerve cells of rabbit in the microencapsulated group and 10 μL sciatic nerve cells of rabbits in the only suspension group; respectively. No graft was placed in the only injured group. MAIN OUTCOME MEASURES： On the 1^st, 3^rd, 7^th, 14^th and 28^th days after operation, immunohistochemistry （SABC technique） was used to detect distribution and amount of positive-reactive neurons in BDNF of spinal cord samples which were selected as 2 cm away from the injured surface. RESULTS： All the 90 rats were involved in the final analysis. Masses of brown-yellow particles were found in the microencapsulated group, and most of them were distributed in the spinal cord anterior horn neurons and glial cells. The positive-reactive neuron particles were also found in the white matter and gray matter. On the 3^rd, 7^th, 14^th and 28^th days after operation, amount of positive-reactive neurons in BDNF in the microencapsulated group was higher than that in the only injured group （P 〈 0.01） and only suspension group （P 〈 0.05）. CONCLUSION： After transplanting microencapsulated nerve cell suspension into injured spinal cord of rats, distribution and amount of positive-reactive neurons in BDNF of local samples at injured surface are increased remarkably as compared with those by using tissue cell transplantation.

Human breast carcinoma xenografts in nude mice

OBJECTIVE: To investigate spontaneous metastasis, micrometastasis and genetic stability in human breast carcinoma xenografts in nude mice. METHODS: Intact tissue from surgical specimens from breast carcinoma patients was xenografted into nude mice and transplanted from generation to generation. Cells from the xenografts were cultured in vitro and retransplanted into nude mice. Microsatellite DNA in the genome of human breast carcinomas, xenotransplanted tumors and metastases in nude mice were analyzed at three microsatellite loci. RESULTS: The tumorigenicity of orthotopic xenotransplantation was 88.6% (31/35), with a metastatic rate of 41.9% (13/31). Cells from xenotransplants were successfully cultured in vitro. The taking rate of retransplantation into nude mice and the spontaneous lung metastasis rate were both 100% (10/10). Microsatellite DNA sequences in the genome of xenotransplanted tumors and metastases in nude mice were identical with that of the original human breast carcinoma at three microsatellite loci. CONCLUSIONS: Tumorigenicity and metastatic potential can be improved in human breast carcinoma xenografts using intact fresh tumor tissue and orthotopic grafts. Xenotransplanted tumors and tumors after serial passage maintained the genetic stability. The detection of microsatellite DNA may identify micrometastases in a nude mouse model.

Early reports of bone repair techniques and bone xenograft in Persian traditional medicine

Bone grafting is typically thought to be a modern concept and practice,but the principles of bone grafting procedures were established before the＂metallurgic age＂in orthopedics[1].Bone grafting is indicated in orthopedic conditions such asbone loss and non-union that are consequences of injuries and disease conditions.Today,

Expression and cellular localization of interleukin 8 mRNA and protein in the area of xenogenic bone implant

Objective: To observe the expression and cellular localization of interleukin 8 (IL 8) mRNA and protein in the area of xenogenic bone implant. Methods: The bovine cancellous bone granules were implanted into the thigh muscles of mice. The samples were taken 4, 7, 14 and 21 days after implantation. IL 8mRNA and protein in the site of implant were assayed by in situ hybridization and immunocytochemical techniques. Results: The expression of IL 8mRNA and protein were observed in all specimens 4, 7, 14 and 21 days after implantation. IL 8mRNA was expressed mainly by the neutrophils, monocytes, macrophages and fibroblasts at 7th day post implantation. Some mesenchymal cells, multinucleated giant cells, vascular endothelial cells and smooth muscle cells also expressed IL 8mRNA in the area of xenogenic bone implant at 14th and 21st days. Immunocytochemical studies demonstrated the same results as that of in situ hybridization. Conclusions: Many different kinds of cells express IL 8mRNA and secret IL 8 in the area of xenogenic bone implant, suggesting that IL 8 may play an important role in local immunity of xenogenic bone graft.