Establishing Human Neuroblastoma Model From Subcutane Transplantation In The Athymic Mice And HIF-1α And Its Related Proteins Expression

ObjectiveNeuroblastomas are the most common malignant solid tumors in children, with features of rapid growth, high degree of malignancy and so on.The statistics of Pediatric Oncology Group in 1999 shows that NB accounts for all cases of pediatric malignant solid tumors 21.4%. It is not only highly malignant, invasive ability, and early transfer rate, more advanced cases, treatment of poor results.Therefore, how to improve the clinical research and diagnosis and treatment of NB is still concerned by the domestic and foreign scholars. Establish a reliable animal model is the cornerstone to success. The commonly used animal models of human neuroblastoma are subcutaneous tumor of nude mice and neuroblastoma in situ tumors. Though congenital malformations and the diagnosis and treatment of infectious diseases have been markedly improved in today's society, NB is still a serious threat to the life and health of children. With the uncontrolled proliferation of tumor cells growth, requires a lot of nutrients and oxygen is consumed to form an anoxic environment, which is very common in human solid tumors.To overcome the lack of nutrients and the effects of hypoxia on tumor growth, tumor angiogenesis within the tumors continue to grow and progress as a necessary condition. The transcription factor hypoxia-inducible factor is a key regulator responsible.For the induetion of genes that facilitate adaptation and survival of cells and the whole organism from normoxia to hypoxia.HIF is anα/βheterodimer that binds hypoxia response elements (HREs) at target gene loci under hypoxic conditions. HIF acts as a key regulator responsible for the adaptation in hypoxic conditions of tumors, which has been proved in many studies in the world.HIF can also promote the growth of tomors by regulating the expression of some kinds of cytokines, such as vascular endothelial growth factor, glucose transporter-1 and transforming growth faetor-a, ete.These cytokines are also proved to be helpful to the growth and the metabasis of tumors.To establish human neuroblastoma model from subcutane transplantation in the athymic mice and observe HIF-1 a and its related proteins expression in order to find out if HIF-αand its related proteins play a role in the growth of neuroblastoma and provide new methods for the investigation of etiopathogenesis and diagnosis of neuroblastoma.MethodsWe establish human neuroblastoma model from subcutane transplantation in the athymic mice with human adrenal neuroblastoma cell lines,the positive control group contains 40 specimens of neuroblastoma tissue from the patients who admitted in our hospital during the past five years.The negative group contains 30 specimens of normal brain tissue from nude mice. The expression of of HIF-1α,VEGF and TGF-a in neuroblastoma was detected by immunohistochemical techniques, and the test results were statistically analyzed.The tumor group was divided into HIF-la positive group and the HIF-la negative group combined with immunohistochemistry results, the survival of the two groups (body weight, tumor weight, survival days) were compared, and the test results were statistically analyzed.ResultsFour weeks later,NB occurred in 40 mice, tumor formaion was 80%.The positive expression of the three kinds of proteins is expressed as brown granules in cytoplasm.The positive rate of tumor group and the positive control group is 73.70%±10.68%,69.80%±9.91%,71.43%±8.52%and 9.67%±4.53%,6.80%±3.40%, 6.50%±4.44%, there were significant difference between tumor group and negative control group of the three proteins (P＜0.01).The IOD of HIF-1α,VEGF,TGF-a in tumor group and positive control group were 141.97±7.98,151.85±14.35, 139.94±4.50,141.34±6.44,144.06±8.51,149.00±13.63, which were higher than the negative control group (P<0.01).In the tumor group and positive control group there is a positive correlation between the expression of HIF-1αand VEGF (χ2=7.778 r=0.504 P＜0.01), there is no correlation between the expression of HIF-1αand TGF-α(χ2=0.208 r=0.934 P>0.05). The expression of HIF-1αhas a great influence on the survival time(P<0.05, LongRank, Breslow, Tarone-Ware tests).Conclusions1. It is a good method to establish human neuroblastoma model. The time is short and achievementratio is high, further more, biology behavior is close to primary hepatic carcinoma.2. The overexpression of HIF-1α,VEGF,TGF-αwere found in neuroblastoma.3. In the tumor tissue, there is a positive correlation between the expression of HIF-1αand VEGF, there is no significant correlation between the expression of HIF-1αand TGF-α, HIF-1αand VEGF play an important role in tumor invasion and metastasis of blood vessels.4. Compared with the HIF-1αnegative group, the HIF-1αpositive group mice have a heavier body weight, larger tumor, shorter survival time,The expression of HIF-1αis related to the prognosis of neuroblastoma.