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find Keyword "resistance" 180 results
  • Effect of Saxagliptin on the β-cell Function of Patients with Type 2 Diabetes: A Systematic Review

    Objective To evaluate the effects of saxagliptin on β cell function of type 2 diabetic patients. Methods The Cochrane Library, PubMed, EMbase, CBM, VIP, and CNKI were searched from their establishment to November, 2011, for relevant randomized controlled trials on the effects of saxagliptin on β cell function in type 2 diabetic patients. Language was limited to Chinese and English only. Two reviewers independently screened the literature according to the inclusion and exclusion criteria, extracted the data, and evaluated and cross-checked the methodological quality. Then meta-analysis was conducted using RevMan 5.0 software. Results Five RCTs were included. The results of meta-analysis showed that: HOMA-B was significantly increased in the saxagliptin (or saxagliptin plus routine treatment) 2.5 mg, 5 mg, and 10 mg groups (MD=8.03, 95%CI 4.57 to 11.48, Plt;0.000 01; MD=7.50, 95%CI 4.27 to 10.73, Plt;0.000 01; MD=17.45, 95%CI 13.93 to 20.97, Plt;0.000 01); HOMA-IR was similar between saxagliptin 2.5 or 10 mg group, and control group (MD= –0.05, 95%CI –0.18 to 0.08, P=0.47; MD= –0.18, 95%CI –0.60 to 0.24, P=0.4). Conclusion Current evidence shows that saxagliptin is effective in improving β cell function and insulin resistance. Due to short follow-up and small sample size, this conclusion has to be further proved by more high-quality RCTs.

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  • Effect of Tumor Initiating Cells and Epithelial-Mesenchymal Transition in Tumor Metastasis and Drug Resistance

    Objective To summarize the roles of tumor initiating cells (TICs) and epithelial-mesenchymal transition (EMT) in tumor metastasis and drug resistance. Methods Domestic and international publications online which involving TICs,EMT,and its roles in tumor metastasis and drug resistance in recent years were reviewed. Results TICs were self-renewal cells and had the ability to give rise to more differentiated cell types,and played an important role in tumor metastasis and drug resistance. Various markers had been used to identify TICs,such as CD133,CD44,and so on. EMT was the process by which epithelial cells losed polarity and detach from the epithelial sheet, and acquired a motile mesenchymal phenotype,usually observed in embryo development and wound healing. It also could promote tumor progression and metastasis,and may also be responsible for the ability of tumors to evade the body’s immune response. EMT may be the reasons of TICs that drived tumor metastasis and recurrence. TICs or EMT as a target for treatments may effectively prevent tumor recurrence and improve patient’s survival. Conclusions EMT is probably the mechanism that TICs promote tumor metastasis and drug resistance. More effective target therapies for cancer may be found if we know more about TICs and EMT.

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  • Progress of mTOR Signal Pathway in Chemo-Resistance of Gastric Cancer

    Objective To review the role of mTOR signal pathway in chemo-resistance of gastric cancer. Methods Domestic and international publications related mTOR signal pathway in chemo-resistance of gastric cancer in recent years were collected and reviewed. Results mTOR was a central signaling molecule of mTOR signal pathway, which regulated key cellular processes such as cell growth, cell proliferation, cell metabolism, and angiogenesis. Signaling molecules of mTOR signal pathway were overexpressed in gastric cancer. Moreover, mTOR signal pathway might play an important role in chemo-resistance of gastric cancer, and tumor stem cells were involved in it too. Conclusion As mTOR signal pathway plays an important role in chemo-resistance of gastric cancer, the combination of mTOR inhibitors and chemotherapy drugs may overcome the chemo-resistance of gastric cancer.

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  • Expressions of Multidrug Resistance Gene Products in Gastric Cancer Tissues and The Clinical Significance

    Objective To detect the characteristic of multidrug resistance gene products expressions in gastric cancer tissues, including glutathione-s-transferase π (GST-π), P-glycoprotein (P-gp), topoisomerase Ⅱ (Topo-Ⅱ), thymidylate synthase (TS), and multidrug resistance related protein (MRP), and analyze their clinical significance for the therapy of gastric cancer. Methods SP immunohistochemical stain was used to detect GST-π, P-gp, Topo-Ⅱ, TS and MRP expressions in sample of 48 gastric cancer tissues and 10 normal gastric mucosa. And their corresponding clinical data were comprehensive analyzed. Results The expressions of GST-π, P-gp, Topo-Ⅱ, TS and MRP had notable differences between the gastric cancer tissues and normal gastric mucosa (GST-π: P<0.01; P-gp: P<0.01; Topo-Ⅱ: P<0.01; TS: P<0.05; MRP: P<0.05). Positive expression rates of GST-π, P-gp, Topo-Ⅱ, TS and MRP in gastric cancer tissues were 72.9% (35/48), 56.3% (27/48), 83.3% (40/48), 41.7% (20/48) and 39.6% (19/48), and positive expression rates of them in normal gastric mucosa were 10.0% (1/10), 0 (0/10), 0 (0/10), 0 (0/10) and 0 (0/10) corresponding. Their positive expression rates were closely relevant to the degree of differentiation (P<0.01), but not to the patients’ sex, age, tumour site, size of tumour, invasive depth and lymph node metastasis (Pgt;0.05). Conclusions The expressions of GST-π, P-gp, Topo-Ⅱ, TS and MRP in gastric cancer tissues exist obvious heterogeneity. Their overexpression underlie the multidrug resistance of gastric cancer. The joint detection of GST-π, P-gp, Topo-Ⅱ, TS and MRP can be looked as an important symbol for guiding its chemotherapy.

    Release date:2016-08-28 03:48 Export PDF Favorites Scan
  • A New Tool for Medical Research ——ATP-Binding Cassette Transporter Families

    Objective  To review the application advancements of ATP-binding cassette (ABC) transporter in medical research.Methods  Relevant literatures about the applications of ABC families in medical research were reviewed. Results  ABC families mainly took roles in transporting substances across cell membrane. Some of them were useful for the prediction of drug resistance and the prognosis of malignant tumors. Others were target s for molecular researches. Their expressions or mutations might be related with the occurrence of diseases. Conclusion ABC families are very important in the diagnosis and therapy for diseases. Thus they are very promising tools for future medical research.

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  • Effects of Survivin Antisense RNA on Apoptosis and Reversing Drug Resistance of SGC7901 Cells

    Objective To study the effects of survivin antisense RNA on SGC7901 cell’s apoptosis and chemosensitivity to taxotere, and to investigate its effect on the expression of multi-drug resistance gene-1 (MDR-1). Methods Survivin antisense eukaryotic vector anti-pcDNA3-svv was transfected into SGC7901 cell lines by lipofectamine and positive clones were screened out then. Survivin protein and MDR-1 mRNA were measured by western blot and RT-PCR, respectively. Apoptosis that was induced by anti-pcDNA3-svv was observed by electronic microscope, and the sensitivity of SGC7901 cell to taxotere was examined by MTT. Results The expressions of survivin protein and MDR-1 mRNA in transfected SGC7901 cells both decreased more significantly than that of non-transfected cells (P<0.05, P<0.01), and the indices of MDR of transfection group and non-transfection group were 0.196±0.013 and 3.126±0.019, respectively, at the late phase of apoptosis, which had a significant difference between each other (P<0.01), IC50 of the transfected cells to taxotere was (16.7±1.98) ng/ml and that of the non-transfected cells was (55.7±1.89) ng/ml, which also had a significant difference (P<0.01). Conclusion Surivivin antisense RNA could induce the apoptosis of SGC7901 cancer cell line and could increase the cells’ sensitivity to taxotere, which may help to reverse drug resistance.

    Release date:2016-08-28 04:08 Export PDF Favorites Scan
  • Establishment of Adriamycin-Resistant Human Pancreatic Cancer SW1990/ADM Cell Line and to Investigate Its Resistance Mechanism

    【Abstract】ObjectiveTo establish adriamycin (ADM) resistant pancreatic cancer cell line SW1990/ADM and to investigate its drug resistance mechanism.MethodsADM-resistant pancreatic cancer cell line SW1990/ADM was obtained by culture of pancreatic cancer cell line SW1990 in vitro with intermittently increasing the concentration of ADM in the culture medium for ten months. After two months of drug free culture, its biological characteristics, drug sensitivity as well as the expression and function of multidrug resistant gene 1 (mdr1) were detected, respectively. ResultsCompared with the parental cell line, SW1990/ADM showed great changes in biological characteristics and developed a cross resistance to various chemotherapy drugs. The drug resistance indexes of cell line SW1990/ADM to ADM, mitomycin, fluorouracil and gemcitabine were 49.60, 7.25, 3.80 and 1.25, respectively. The level of mdr1 mRNA expression in cell line SW1990/ADM was much higher than that of the parental cell line(P<0.01). ConclusionWe have established adriamycin resistant pancreatic cancer cell line SW1990/ADM with multidrug resistance phenotype, its multidrug resistance is positively relevant to the expression of mdr1.

    Release date:2016-08-28 04:30 Export PDF Favorites Scan
  • Reversal of Multidrug Resistance Gene mdr1 of Drug-Resistant Human Hepatocellular Carcinoma Cells with Antisense Oligodeoxynucleotide in Vivo

    Objective To investigate the reversal of the multidrug resistant gene mdr1 in vivo by antisense oligodeoxynucleotide (ASODN) on the basis of study in vitro. Methods The cultured drug-resistant human hepatocellular carcinoma cells were injected under the skin of axilla to establish the tumor model of nude mice. mdr1 ASODN accompanied by Lipofectamine were injected locally and ADM was injected intraperitoneally. Control 1 and control 2 were locally injected by Lipofectamine and normal saline separately, and ADM was also injected intraperitoneally. Results As time went on the tumor size increased and from the 5th day on alterations were marked, tumor size in different time phase showed marked difference to the prior time phase with significant difference (P<0.05). Tumor size in group ASODN was marked smaller than that of other 3 groups after the 5th day (P<0.05),while tumor size of group control 1,2 and group SODN in different phase showed no significant difference (Pgt;0.05). The results suggested that SODN and Lipofectamine showed no marked effect on tumor growth of nude mice and ASODN had marked inhibition effect on tumor growth. Conclusion mdr1 ASODN can also reverse multidrug resistance of drug-resistant human hepatocellular carcinoma cells in vivo. After the treatment the tumor’s growth in nude mice will slow down in a range of time.

    Release date:2016-08-28 04:43 Export PDF Favorites Scan
  • Establishment of AdriamycinResistance Cell Substrain SMMC7721/Adriamycin of Human Hepatocellular Carcinoma and Research of Its Characteristics

    ObjectiveTo establish multidrugresistance cell substrain of human hepatocellular carcinoma and to investigate its characteristics.MethodsSMMC7721 cell strain was cultured in Adriamycin(ADM). The multidrugresistance cell substrain SMMC7721/ADM was harvested after a long period of culture by gradually increasing the concentration of ADM and its characteristics were investigated. Results①The drug resistance of SMMC7721/ADM to ADM increased by 33.3 times, to Vincristine 16.8 times, to Diamminedichloroplatinum 2.8 times. ②The drug resistance cell substrain had almost the same growth velocity as its parental generation. The doubling time was 32.0 hours and 30.5 hours respectively. They had the analogous growth curves. ③The obvious difference between the drug resistance cell substrain and its parental generation was that the former’s microvilli became thick, short and scattered by scanning and transmitting electron microscopy. ④The multidrug resistance cell substrain kept the characteristics of hepatocellular carcinoma, it could be transplanted into the subcutaneous tissue of nude mice. ⑤The drug resistance of the cell substrain reduced to 28.0% and 9.2%after removal of the drug for 1 month and 2 months respectively, its drug resistance could remain stable (35.4 times) after 2 months of culture in ADM (0.04 μg/ml).ConclusionThe SMMC7721/ADM cell substrain has the stable fundamental characteristics of a drug resistance cell strain.

    Release date:2016-08-28 04:43 Export PDF Favorites Scan
  • Research Progress of Multidrug Resistance of Breast Cancer

    Objective To review the recent studies on the multidrug resistance of breast cancer. Methods The literatures of recent years on the studies of multidrug resistance, multidrug resistance protein and breast cancer resistance protein were reviewed. Results Multidrug resistance resulted from multiple factors. How to identify the sensibility of chemotherapy drugs and select individual therapeutic regime early were important to improve the survival rate and life quality of breast cancer patients. Conclusion These studies on multidrug resistance of breast cancer are helpful to predicting the effect and outcome of chemotherapy and overcoming the barrier of drug resistance.

    Release date:2016-08-28 04:43 Export PDF Favorites Scan
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