ABSTRACT
This paper aims to study the effects of traditional Chinese medicine on multidrug resistant human gastric cancer cells in the cell proliferation, migration, invasion and apoptosis, and to study the apoptosis-inducing pathway. Different dilutions of extract were used to process human multidrug resistant gastric cancer SGC7901/ADR cells. Cell proliferation inhibition phenomenon was determined by MTT experiment. Nuclear morphological changes of apoptotic cells and apoptotic indexes were observed and determined by Hochest33528 staining followed with fluorescence microscope observing. Flow cytometry was used to detect cell apoptosis rate. Cell migration and invasion ability were observed and determined by Transwell method. Spectrophotometry was used to detect caspase-3 and caspase-9 enzyme activity. Western blotting was used to detect subcellular distribution of cytochrome c. The results showed that extract had obvious inhibition effect on proliferation of gastric cancer multidrug resistant SGC7901/ADR cells, which was time- and concentration-dependent. After processing multidrug resistant gastric cancer SGC7901/ADR cells with extract, the apoptotic index and apoptosis rate were significantly increased than those in the control group, which showed a time- and dose-dependent mode; but if a caspase inhibitor was added, apoptosis index was not obviously increased. Transwell method showed that migration and invasion ability of the extract-processed SGC7901/ADR cells dropped significantly. Spectrophotometry showed that in extract-processed SGC7901/ADR cells, caspase-3 and caspase-9 expression were increased, which had significant differences with the control group. Western blotting test showed that the distribution of cytochrome c decreased in mitochondria, while increased in the cytoplasm (i.e., cytochrome c escaped from mitochondria to the cytoplasm). In conclusion, extract could inhibit the proliferation, migration and invasion, and induce apoptosis in human gastric cancer multidrug resistant SGC7901/ADR cells; and cytochrome c, caspase-9 and caspase-3 might be involved in cell apoptosis induced by extract, suggesting endogenous or mitochondrial apoptotic pathway.
ABSTRACT
BACKGROUND:The use of three-dimensional cel culture techniques can better simulate the cel ular microenvironment, providing new tools for tissue engineering research. OBJECTIVE:To analyze the biomaterial selection and application characteristics in three-dimensional cel culture as wel as applications in tumor tissue engineering. METHODS:We searched Wanfang database and PubMed database 1998-2015 years for relevant literature using keywords of“three-dimensional cultures;scaffold;cel growth;cel differentiation;tumor tissue engineering”in Chinese and English, respectively. RESULTS AND CONCLUSION:The selection and application of three-dimensional scaffold materials is one of the keys. So far, scaffold materials, such as col agen gels, gelatin sponge, agarose, chitosan, demineralized bone matrix, cannot provide the extracel ular matrix similar to the micro-environment in which seed cel growth and proliferation are not affected, and the ability to secrete type II col agen and glycosaminoglycan is decreased, although they can provide three-dimensional space for seed cel s. Biomimetic scaffold characterized as little trauma and strong plasticity gradual y shows its unique advantages. Three-dimensional culture conditions raise pro-angiogenic growth factor secretion from tumor cel s, and this feature is positively correlated with the occurrence of in vivo tumor angiogenesis.
ABSTRACT
Case based teaching or case discussion teaching of basic medical courses can deepen students' understanding of basic medical subjects and allow them to acquire practical and real problem solving skills while leaning the fundamental knowledge of their subjects.This paper discusses the features and advantages of case based teaching and gives a detailed discussion of an effective way to implement case based teaching by taking case based teaching of medical immunology as an example.
ABSTRACT
Apoptosis plays a critical role in tumor genesis and progression. Induction of cancer cell apoptosis with traditional Chinese medicines is at present a hot topic in the research of cancer therapy. It has been found that many active components of traditional Chinese medicines can induce cancer cell apoptosis; ginsenoside and oridonin are two of them that have been studied relatively thoroughly. The mechanisms that ginsenoside and oridonin induce cancer cell apoptosis include arresting cell cycle progression, up-regulating expression of apoptotic promoting proteins, down-regulating expression of apoptotic inhibiting proteins, and activating caspase cascade.
ABSTRACT
Hepatocytes were isolated from livers of adult male Sprague-Dawley rats and cultured in Williams'E Medium with [3 H] thymidine. The effect of 5-hydroxytryptamine (5-HT) was investigated through adding various concentrations (10-8～10-3 mol/L) of 5-HT to the hepatocyte cultures in the presence or absence of epidermal growth factor (EGF) and insulin. The involvement of 5-HT2 receptor was examined by adding a 5-HT2 receptor antagonist, ketanserin (10-6 mol/L), to some of the cultures containing 5-HT. The increment of DNA synthesis was measured by [3 H] thymidine incorporation. The results showed that 5-HT2 (≥10-6 mol/L) significantly (P＜0.05) increased the amount of DNA synthesis induced by EGF and insulin in the cultured adult rat hepaptocytes. The effect of 5-HT in enhancing DNA synthesis began to appear at a concentration between 10-7 and 10-6 mol/L and reached maximum at concentrations of ≥10-4 mol/L. The enhancement of DNA synthesis by 5-HT was significantly (P＜0.05) antagonized by ketanserin, suggesting that this effect of 5-HT was mediated by 5-HT2 receptor subtype.