Study Of Nerve Fiber Distribution In Gastric Cancer Tissues And Interactions Of Cancer Cells And Nerve Cells

Gastric cancer, one of the most common malignant tumors, is the second cause of tumorous death worldwide. In our country, the death rate of gastric cancer lies in the first place among all malignant tumors. It has urged various efforts to research in its pathology, nosogenesis and therapy. It was considered that there was no nerve in tumor tissues for a long time in the area of medicine science. With the development of science and experimental techniques, nerve fibers were found in various tumor tissues. It was reported that nerve fibers in tumor tissues differ from those in normal tissues in their morphology. In gastric cancer, the nerve fibers were scattered and lies among the cancer cells. It was found that there were varicosities of the nerve fibers that directly contacted the cancer cells. In our previous study, we found many nerve fibers containing substance P in human gastric cancer. NGF was also seen to express in gastric cancer tissues and MKN45 cells.It is generally accepted that there are nerve fibers in gastric cancer tissues. While it remains unknown about their functions, their relationship with metastasis, differentiation, age, sex and prognosis etc. In this research, we were to investigate (1) the correlation between nerve distribution and tumor differentiation (2) the interactions of nerve cells and gastric cancer cells.Ⅰ,Comparison of nerve distribution in gastric cancer tissues and normal tissuesObjective To investigate the difference of nerve distribution in gastric cancer tissues and normal gastric tissues. Methods Samples were obtained from the excisional tissues of 66 patients of gastric cancer and stained by anti-GAP43 antibodies. Gastric cancer tissue and normal tissue of the same patient were compared. The density of nerve fibers were analyzed by Image-pro plus 6.0 software and statistical analysis was made by SPSS software. Results The morphology of nerve fibers in gastric cancer tissues differs from nerve fibers in normal gastric tissues. In all of the patients, nerve fiber dendity in gastric cancer tissues was obviously lower than that in normal gastric tissues. Conclusion There were nerve fibers in gastric cancer tissues and their morphology was changed. Nerve fiber density declined in gastric cancer tissues. There was no correlation with age, sex and metastasis.Ⅱ,Comparison of nerve distribution in well differentiated and poorly differentiated gastric cancer tissuesObjective To investigate the difference of nerve distribution in well differentiated and poorly differentiated gastric cancer tissues and to find correlations between nerve fiber density and pathological type of gastric cancer Methods Samples were obtained from the excisional tissues of 28 patients of well-differentiated gastric cancer and 38 patients of poorly-differentiated gastric cancer. All the samples were stained by anti-GAP43 antibodies. The density of nerve fibers were analyzed by Image-pro plus 6.0 software and statistical analysis was made by SPSS software. Results Nerve fiber density in well differentiated gastric cancer was 10323±912 and that of poorly differentiated gastric cancer was 17024±857. Statistical analysis showed P﹤0.05. There was no obvious difference in morphology of nerve fibers. Conclusion Nerve fiber density of poorly differentiated gastric cancer was higher than that of well differentiated gastric cancer.Ⅲ,Comparison of nerve distribution in normal gastric tissues from patients of well differentiated and poorly differentiated gastric cancerObjective To investigate wether there is difference in nerve distribution in normal gastric tissues from patients of well differentiated and poorly differentiated gastric cancer. Methods Samples were obtained from the excisional tissues of 28 patients of well differentiated gastric cancer (Group A) and 38 patients of poorly differentiated gastric cancer (Group B). The tissues were 5cm away from cancer tissues, which were considered as normal tissues. The density of nerve fibers were analyzed by Image-pro plus 6.0 software and statistical analysis was made by SPSS software. Results Nerve fiber density of Group A was 20237±3794 and that of Group B was 23862±4895. Statistical analysis showed P﹥0.05. There was no obvious difference in morphology of nerve fibers. Conclusion There was no difference in nerve fiber density and morphology between normal gastric tissues from patients of well differentiated and poorly differentiated gastric cancer. Ⅳ,Influence of conditioned culture medium from MKN28 / MKN45 cells on the proliferation of PC12 cellsObjective To investigate the influence of cancer cells on nerve cells. Methods MKN28, which is the well differentiated gastric cancer cell line and MKN45, the poorly differentiated gastric cancer cell line were used to prepare the conditioned culture medium, which was used to culture the PC12cells, which is commonly used in nerve research. Normal culture medium was used as control. MTT-assay was performed to test PC12 cell proliferation on day 1, 3, 5and 7. Statistical analysis was made by SPSS software. Results Both the MKN28- and MKN45-conditioned culture medium had the ability to promote the proliferation of PC12 cells. PC12 cells cultured in MKN45-conditioned culture medium seemed to grow faster than in the MKN28-conditioned culture medium. Conclusion Gastric cancer cells, especially poorly differentiated gastric cancer cells could promote the proliferation of nerve cells.Ⅴ,Influence of conditioned culture medium from PC12cells on the proliferation of MKN28 / MKN45 cellsObjective To investigate the influence of nerve cells on gastric cancer cells. Methods PC12 cells were used to prepare the conditioned culture medium. MKN28 and MKN45 cells were separately cultured in the conditioned culture medium with normal culture medium as their control. MTT-assay was performed to test PC12 cell proliferation on day 1, 3, 5and 7. Results The proliferation of both MKN28 and MKN45 cells were promoted by the PC12-conditioned culture medium. The OD value of MKN28 cultured in conditioned culture medium was higher than that in normal culture medium on day 5. The OD value of MKN45 cultured in conditioned culture medium was higher than that in normal culture medium on day 3, 5. Conclusion Nerve cells could promote the proliferation of gastric cancer cells.Ⅵ,In vivo influence of MKN28/MKN45 cells on PC12 cells—Subcutaneous implantation of MKN28- PC12 mixed cells bolus and MKN45- PC12 mixed cells bolus in nude mouseObjective To investigate the influence of cancer cells on nerve cells in vivo. Methods MKN28- PC12 mixed cells bolus and MKN45- PC12 mixed cells bolus were prepared by a series of methods and separately implanted subcutaneously in nude mouse. 10 nude mice were randomly divided into two groups: the MKN28 group and MKN45 group. PC12 cells were labeled with PKH26. The number of PC12 cells in each bolus was 1×10~6 and MKN45/MKN28 were 1×10~7. 6 weeks later, the mixed cells boluses were retrieved, histological stained and observed under fluorescence microscope. Results MKN45- PC12 mixed cells bolus grew faster than the MKN28- PC12 mixed cells bolus. The number of PC12 cells in MKN45 group was obviously higher than in that in MKN28 group. Conclusion Gastric cancer cells could promote the proliferation of nerve cells in vivo and poorly differentiated gastric cancer cells had higher stimulative ability.