2012 Vol. 26, No. 5
The aim of this study was to determine the expression of growth hormone receptor (GHR) in patients with primary gastric adenocarcinoma. We investigated 48 specimens of primary gastric adenocarcinoma and their corresponding normal gastric mucosa. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the expression of GHR. Immunohistochemical analyses revealed that GHR was expressed in human primary gastric adenocarcinoma (36/48, 75.0%) and appeared to be upregulated, compared to the normal mucosa (28/48, 58.3%, P < 0.001). A significant correlation was found between GHR expression and tumor stage (P < 0.001) and tumor differentiation (P < 0.001). The average positive rate of ki-67 in GHR-positive tumors was 16.06%, while the positive rate in GHR-negative tumors was 6.17% (P < 0.01). The average apoptosis index (AI) of GHR-positive tumors was 3.36%, which was significantly lower than that (7.33%) of GHR-negative tumors. In addition, 27 of 48 cases of tumors had GHR mRNA expression, while only 17 of all 48 cases of normal mucosa did so. Our results indicate that the frequency of GHR was significantly higher in primary gastric adenocarcinoma than that in normal gastric mucosa. GHR expression was significantly correlated with tumor differentiation and tumor grade. This finding supported a possible role of growth hormone in primary gastric adenocarcinoma pathophysiology.
MET tyrosine kinase and its ligand, hepatocyte growth factor (HGF), play a pivotal role in the activties of tumor cells. A germline missense variant in exon 2 of the MET gene, N375S (rs33917957 A>G), may alter the binding affinity of MET for HGF and thus modify the risk of tumorigenesis. In this study, we performed a case-control study to assess the association between N375S and gastric cancer risk in 1,681 gastric cancer cases and 1,858 cancer-free controls. Logistic regression analysis was applied to estimate crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between genotypes and gastric cancer risk. We found that MET N375S variant genotypes (NS/SS) were associated with a significantly decreased risk of gastric cancer (OR = 0.78, 95% CI = 0.63-0.96, P = 0.021) compared with the wildtype homozygote (NN). The finding indicates that this germline variant in MET may decrease gastric cancer susceptibility in Han Chinese.
The purpose of this study was to determine the relationship between hypermethylation of DACT1 gene promoter and lower mRNA expression in bladder urothelial carcinoma tissue. The methylation status of 29 urothelial carcinoma samples and 29 normal tissue samples were examined by methylation-specific polymerase chain reaction (MSP). The DACT1 mRNA transcript levels and DACT1 protein levels in all samples were then evaluated to define the relationship between the methylation status of the DACT1 promoter and its expression at the transcriptional and translational levels. Decreased expression of DACT1 was detected in 89.66% of urothelial carcinomas (26/29; P < 0.005). Promoter hypermethylation was found in 58.62% (17/29) urothelial carcinomas and 25% (7/29) normal tissues, respectively (P < 0.05). DACT1 expression was lower in tissues where the DACT1 gene promoter was hypermethylated than in unmethylated tissues (0.25±0.17 vs 0.69±0.30, P < 0.05). DACT1 gene hypermethylation was closely related to tumor size, grade and stage (P < 0.05). Our results indicate that silencing and downregulation of DACT1 mRNA may be implicated in carcinogenesis and the progression of bladder urothelial carcinoma, and may be a potential prognostic factor.
We sought to determine whether STAT3 mediated tamoxifen resistance of breast cancer stem cells in vitro. The capacities for mammosphere formation and STAT3 expression of CD44+CD24-/low MCF-7 and MCF-7 were observed. The CD44+CD24-/low subpopulation ratio and its sensitivity to adriamycin were analyzed in MCF-7 and TAM resistant (TAM-R) cells. Cell cycle, apoptosis, STAT3 and phospho-STAT3 changes were observed after treatment with tamoxifen. Small interference RNA-mediated knockdown of STAT3 in TAM-R cells was also performed. CD44+CD24-/low MCF-7 showed higher capacities for mammosphere formation and STAT3 expression than total MCF-7. The CD44+CD24-/low subpopulation was also upregulated in TAM-R cells with less sensitivity to adriamycin than MCF-7. Cell cycle changes, anti-apoptotic effects and STAT3 changes were also found. Meanwhile, the knock-down of STAT3 in TAM-R resulted in an increase in sensitivity to tamoxifen. It is concluded that STAT3 plays an essential role in breast cancer stem cells, which correlated with tamoxifen resistance.
Gastric cancer stem-like cells (GCSCs) have been identified to possess the ability of self-renewal and tumor initiation. However, the mechanisms involved remain largely unknown. Here, we isolated and characterized the GCSCs by side population (SP) sorting procedure and cultured sphere cells (SC) from human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, HGC-27 and MKN-28. The sorting and culture assay revealed that SP cells proliferated in an asymmetric division manner. In addition, SP cells exhibited a higher potential of spheroid colony formation and greater drug resistance than non-SP cells (NSP). Moreover, the SC were found with enhanced capabilities of drug resistance in vitro and tumorigenicity in vivo. Sox2 mRNA and protein was highly and significantly overexpressed in the SP cells and SC. Importantly, downregulation of Sox2 with siRNA obviously reduced spheroid colony formation and doxorubicin efflux, as well as increased apoptosis rate in sphere cells in vitro and suppressed tumorigenicity in vivo. These results suggest that both SP cells and cultured SC enrich with GCSCs and that Sox2 plays a pivotal role in sustaining stem cell properties and might be a potential target for gastric cancer therapy.
Glycine is a well-documented cytoprotective agent. However, whether it has a protective effect against myocardial ischemia-reperfusion injury in vivo is still unknown. By using an open-chest anesthetized rat model, we found that glycine reduced the infarct size by 21% in ischemia-reperfusion injury rats compared with that in the vehicle-treated MI/R rats. The left ventricular ejection fraction and fractional shortening were increased by 19.11% and 30.98%, respectively, in glycine-treated rats. The plasma creatine kinase levels in ischemia-reperfusion injury rats decreased following glycine treatment. Importantly, administration of glycine significantly inhibited apoptosis in post-ischemia-reperfusion myocardium, which was accompanied by suppression of phosphorylated p38 mitogen-activated protein kinase and c-Jun NH2-terminal kinase, as well as the Fas ligand. These results suggest that glycine attenuates myocardial ischemia-reperfusion injury in vivo by inhibiting cardiomyocytes apoptosis.
The aim of the present study was to determine whether the sensitivity of thymocytes to X-ray radiation depends on their proliferative states and whether radiation impairs the maturation of donor-derived thymocytes in recipient thymus. We assigned 8-week-old C57BL/6J mice into three treatment groups: 1) untreated; 2) X-ray radiation; 3) X-ray radiation plus bone marrow transplantation with donor bone marrow cells from transgenic mice expressing enhanced green fluorescent protein (GFP) on a universal promoter. After 4 weeks, the size of the thymus, the number and proliferation of thymocytes and ratios of different stage thymocytes were analyzed by immunohistochemistry and flow cytometry. The results showed that: 1) CD4+CD8+ thymocytes were more sensitive to X-ray radiation-induced cell death than other thymocytes; 2) the proliferative capacity of CD4+CD8+ thymocytes was higher than that of other thymocytes; 3) the size of the thymus, the number of thymocytes and ratios of thymocytes of different stages in irradiated mice recovered to the normal level of untreated mice by bone marrow transplantation; 4) the ratio of GFP-positive CD4+CD8+ thymocytes increased significantly, whereas the ratio of GFP-positive CD4+ or CD8+ thymocytes decreased significantly. These results indicate that the degree of sensitivity of thymocytes to X-ray radiation depends on their proliferative states and radiation impairs the maturation of donor-derived CD4+CD8+ thymocytes in recipient thymus.
Exposure of skin to solar ultraviolet (UV) radiation induces photo-damage. Ultraviolet B (UVB) is the major component of UV radiation which induces the production of reactive oxygen species (ROS) and plays an important role in photo-damage. Hydrogen gas reduces ROS and alleviates inflammation. In this study, we sought to demonstrate that hydrogen-rich saline has the effect on skin injuries caused by UVB radiation. UVB radiation was irradiated on female C57BL/6 rats to induce skin injury. Hydrogen-rich saline and nitrogen-rich saline were administered to rats by intraperitoneal injection. Skin damage was detected by microscope after injury. UVB radiation had a significant affection in tumor necrosis factor alpha, interleukin (IL)-1β and IL-6 levels, tissue superoxide dismutase, malondialdehyde and nitric oxide activity. Hydrogen-rich saline had a protective effect by altering the levels of these markers and relieved morphological skin injury. Hydrogen-rich saline protected against UVB radiation injury, possibly by reducing inflammation and oxidative stress.
Hypertrichosis is one of the most common side effects of systemic cyclosporine A therapy. It has been previously shown that cyclosporine A induces anagen and inhibits catagen development in mice. In the present study, to explore the mechanisms of cyclosporine A, we investigated the effects of cyclosporine A on hair shaft elongation, hair follicle cell proliferation, apoptosis, and mRNA expression of selected growth factors using an organ culture model of mouse vibrissae. In this model, cyclosporine A stimulated hair growth of normal mouse vibrissae follicles by inhibiting catagen-like development and promoting matrix cell proliferation. In addition, cyclosporine A caused an increase in the expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and nerve growth factor (NGF), and inhibited follistatin expression. Our findings provide an explanation for the clinically observed effects of cyclosporine A on hair growth. The mouse vibrissae organ culture offers an attractive model for identifying factors involved in the modulation of hair growth.
We sought to construct the adenoviral vector carrying the gene encoding mouse telomerase reverse transcriptase (mTERT), as well as detect its expression and effect on the proliferation of neuronal stem cells. mTERT was amplified by RT-PCR and then the eukaryotic expression vector of pDC-EGFP-TERT was constructed. After DNA sequence analysis, we detected that there were 293 cells transfected with pDC-EGFP-TERT and helper adenovirus plasmid pBHG lox ΔE1, and three Cre using Lipofectamine 2000 mediation, named Ad-mTERT-GFP, to package adenoviral particles. The Ad-mTERT-GFP was used to infect neuronal stem cells and then the expression and activity of mTERT were detected. In addition, Bromodeoxyuridine labeling test identified the impact of mTERT overexpression on proliferation of neuronal stem cells. The recombinant adenoviral vector confirmed that mTERT was successfully constructed. Overexpression of mTERT stimulated the proliferation of neuronal stem cells both in vitro and in vivo. mTERT overexpression via adenoviral vector carrying mTERT cDNA upregulated the ability of proliferation in neuronal stem cells.
2012, 26(5): 389-393. doi: 10.7555/JBR.26.20120029
Micro-RNAs (miRNAs) have been found to be implicated in a very wide range of physiological processes. This study was aimed to investigate the regulation of miRNA-429 (miR-429) in gastric cancer cells on cell proliferation and apoptosis. Quantitative PCR was employed to detect the expressions of miR-429 after eukaryotic expression plasmid of miR-429 and its inhibitor were transiently transfected into poorly differentiated human gastric cancer cell line BGC823. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assays were used to examine proliferation ability. Apoptosis was analyzed by flow cytometry after transfection. The results showed that 48 h after transfection, overexpression of miR-429 reached maximum efficiency. Compared with mock transfection, miR-429 inhibited tumor cell proliferation significantly (P < 0.05) at 48 h and 72 h. of Overexpression of miR-429 promoted tumor cell apoptosis when compared with mock transfected cells (P < 0.05). On the contrary, miR-429 inhibitor promoted tumor cell proliferation and inhibited apoptosis when compared with controls (P < 0.05). Our results suggested that miRNA-429 may serve as a tumor suppressor during tumorigenesis of gastric cancer and may be a potential gastric cancer therapeutic target.
The author would like to inform the readers that the correct form of title "Role of remote sensing, geographic bioinformatics system and bioinformatics in kala-azar epidemiology" , content in ab-stract "The computational approaches like remote sensing, geographic information system (GIS) and bioinformatics are the key re-sources for the detection and distribution of vectors, patterns, ecologi-cal and environmental factors and genomic and proteomic analysis.", and keyword "geographical bioinformatics systems (GIS)" should be read as follows: title "Role of remote sensing, geographical bioinformation system and bioinformatics in kala-azar epidemiology", content in abstract "The com-putational approaches like remote sensing, geographical information system (GIS) and bioinformat-ics are the key re-sources for the detection and distribution of vectors, patterns, ecological and envi-ronmental factors and genomic and proteomic analysis.", and keyword "geographical bioinformation system (GIS) ". We apologize for any inconvenience this error may have caused.