| Tumor is the one of the killers which hazard human health. Oncological surgery, tumor therapeutic radiology and tumor chemical therapy are three sustentaculums of modern tumor therapy which have characteristics respectively and supplement each other. However, many malignant tumors have resistance to postsurgical chemoradiation, which is one of the tough problems that puzzle tumor therapy. Many proteins have been found to correlate with the neoplasm drug resistance and HO-1 is one of them.HO-1 is the rate-limiting enzyme that catalyzes the conversion of heme to biliverdin, carbon monoxide(CO) and iron. HO-1 is both a kind of anti-oxidant enzyme and an endogenous antiapoptosis protein which correlates with some diseases (such as tumors, atherosclerosis, hypertension, etc.) clinically.It has been found that HO-1 has correlation with tumors and HO-1 is up-regulated in solid tumors compared with the normal tissue from 1980s. But the functions of HO-1 in different tumors are different. On one hand HO-1 promotes rapid growth of some tumors such as lung cancer, colon cancer, prostate cancer, squamous-celled carcinoma of oral cavity, esophageal cancer, etc. and protects neoplasm metastasis and proliferation through anti-apoptosis effect. The in vitro and in vivo experiments have demonstrated that zinc protoporphyrin ( the inhibitor of HO-1) could enhance the chemotherapy sensitivity of some tumors such as lung cancer, colon cancer, prostate cancer and reduce the growth velocity. On the other hand high expression of HO-1 can inhibit the proliferation of some tumors cells. The study of Hill showed that the up-regulation of HO-1 could inhibit the proliferation of breast cancer cells. It can be seen that it is necessary to investigate the functions and the mechanisms of HO-1 in more tumors.The studies of the relationship between HO-1 and tumors began with the cells and the expression styles of HO-1 were regulated in different tumors. The relationship between HO-1 and gastric carcinoma is uncertain and it is necessary to investigate the effect of the activity of HO-1 on gastric carcinoma. In addition, the studies about the effect of the activity of HO-1 on the characteristics of tumors are less. The present study only use the inductor of inhibitor of HO-1 to treat mice to observe the effect of the expression of HO-1 on the characteristics of tumors. But the the mechanisms of the drugs are complicated and the function styles are different and the targets are not good. The experimental data cannot reflect the effect of of HO-1 on the characteristics of tumors. Although it is presumed that the expression level of HO-1 correlates to the generation of tumors from the amount of HO-1 promoter (GT)n, it is short of enough data and direct proof. The mice model with the different expression levels of HO-1 is the most effective and direct method of solving the effect of HO-1 expression level on the processes of tumors. Therefore we carried out the following experiments:The first part The effect of the activity of HO-1 on the drug resistance of gastric adenocarcinoma cells BGC823 Gastric carcinoma is a common cancer and there is a little reports about the correlation with HO-1. We constructed the recombinant plasmids pcDNA3.1(+)-HHO-1 and pcDNA3.1(+)-HHO-1G143H and transfected them to gastric adenocarcinoma cells BGC823. The expression and enzymatic activity of HO-1 were examined and the drug resistance of gastric adenocarcinoma cells with changed HO-1 was observed. The results showed BGC823 cells transfected with pcDNA3.1(+)-HHO-1 had elevated expression of HO-1 mRNA and protein. While the decreased activity of HO-1 was showed in cells transfected with pcDNA3.1(+)-HHO-1G143H. The cell resistance to Cisplatin was changed, and the drug resistance of cells transfected with pcDNA3.1(+)-HHO-1G143H was higher than that of wild BGC823 cells. The results indicated that the decrease of HO-1 activity in gastric adenocarcinoma cells might influence the effect of Cisplatin chemotherapy.The second part The establishment of transgenic mice models of BDF1HO-1 and FVBHO-1 The fragments of purifed HO-1 were injected to the pronucleus of mice zygotes and the zygotes with good conditions were transplanted into fallopian tubes of the pseudopregnant mice. Five lines of transgenic mice of BDF1HO-1 and FVBHO-1 were obtained. Four lines of BDF1HO-1 mice were 371L with high expression of HO-1, 820L with middle expression of HO-1, G143HL with HO-1 mutant, the wild line and one line of FVBHO-1 was the dominant negative mutation of HO-1G143H. The positive rate of F0 generation of transgenic mice FVBHO-1 was 3.8% which was much lower than the common ratio 10-30% and was also lower than that of BDF1HO-1 dominant negative mutation. So it was presumed that the change of HO-1 activity had effect on the reproduction of FVB mice. HO-1 expression position in the spleen of transgenic mice was changed and the expression of HO-1 was high in the red marrow. Since there are lots of macrophagocytes, B lymphocytes and plasmacytes in the red marrow, it is presumed that high expression of HO-1 in this area might affect the anti-inflammatory capability of the animals.The third part The study of the effect of transgenic mice BDF1HO-1 on the growth and metastasis of melanoma cells We used three lines of BDF1HO-1 i.e. 371L, G143HL and the wild line to investigate the effect of HO-1 activity in animals on the growth and metastasis of melanoma cells B16F10. Statistic research of tumors emergence time, growth velocity, animals lethality and the amount of pulmonary metastasis was carried out and the results showed that activity of HO-1 in animals had great effect on the growth of animals which was inoculated by tumor cells. The growth velocity of tumors, lethality and the number of metastasis in lungs of 371L with high expression of HO-1 were lower than those in the wild mice. Further the HE stain of the subcutaeous tumors showed that there was less inflammatory cell infiltrate in the animals of 371L. It can be seen that animals with high activity of HO-1 can resist the metastasis of melanoma B16F10 effectively, inhibit the growth velocity of tumors in animals, delay or avoid the formation of tumors mass and inhibit inflammatory.In conclusion, we changed the expression and activity of HO-1 in gastric adenocarcinoma cells BGC823 and found that the decreased activity of HO-1 in the cells might elevate the resistance to Cisplatin. At the same time, the transgenic mice BDF1HO-1 and FVBHO-1 were established successfully through transgenetic technology. Further, four lines of BDF1HO-1 were obtained. The experiments of the growth and metastasis of melanoma cells in three lines of BDF1HO-1 showed that the elevated activity of HO-1 helped to reduce the growth and metastasis of tumors and inhibit inflammatory. This builds up the foundation to the study of the effect of the activity change of HO-1 on tumors.
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