c-MYC mediates the crosstalk between breast cancer cells and tumor microenvironment.

The MYC oncogenic family is dysregulated in diverse tumors which is generally linked to the poor prognosis of tumors. The members in MYC family are transcription factors which are responsible for the regulation of various genes expression. Among them, c-MYC is closely related to the progression of tumors. Furthermore, c-MYC aberrations is tightly associated with the prevalence of breast cancer. Tumor microenvironment (TME) is composed of many different types of cellular and non-cellular factors, mainly including cancer-associated fibroblasts, tumor-associated macrophages, vascular endothelial cells, myeloid-derived suppressor cells and immune cells, all of which can affect the diagnosis, prognosis, and therapeutic efficacy of breast cancer. Importantly, the biological processes occurred in TME, such as angiogenesis, immune evasion, invasion, migration, and the recruition of stromal and tumor-infiltrating cells are under the modulation of c-MYC. These findings indicated that c-MYC serves as a critical regulator of TME. Here, we aimed to summarize and review the relevant research, thus to clarify c-MYC is a key mediator between breast cancer cells and TME. Video Abstract.

[Comparative evaluation of Hebei HIV-1 p24 kit for the detection of human immunodeficiency virus].

OBJECTIVE: To probe into the feasibility of screening anti-HIV compounds by using HIV-1 p24 detection kit made by Hebei Medical University. METHODS: The sensitivity, reproducibility and efficacy of the Hebei p24 kit were evaluated compared with the commercially available Vironostika HIV-1 Antigen Microelisa System (Biomerieux). RESULTS: Hebei p24 kit had high sensitivity and good reproducibility. In vitro screening demonstrated that there was no statistically significant difference (P greater than 0.05) between these two kits in assessing anti-HIV compounds. CONCLUSION: Hebei p24 kit could be used as an easily affordable alternative method for detection of HIV-1 in screening anti-HIV compounds.

Interaction models of CYP1A1, GSTM1 polymorphisms and tobacco smoking in intestinal gastric cancer.

AIM: To explore the interaction models of the cytochrome P-450 (CYP) 1A1 Val variant and glutathione S-transferase (GST) M1 null polymorphisms with tobacco smoking in the occurrence of intestinal gastric cancer. METHODS: A community-based case-control study was conducted in Yangzhong. Subjects included 114 intestinal types of gastric cancer with endoscopic and pathological diagnosis during January 1997 and December 1998, and 693 controls selected from their spouse, siblings or siblings-in-law who had no history of digestive system cancer. Logistic regression was used to estimate the interaction models. RESULTS: The frequency of the CYP1A1 Val variant allele in cases did not differ from that in controls. The OR of GSTM1 null genotype was 2.0 (95% confidence interval (95%CI): 1.2-3.1, P<0.01). It showed a significant type 2 form of interaction model when both CYP1A1 Val variant allele and former tobacco smoking existed (i.e., among the multiplicative effects, the disease risk is increased by the tobacco exposure alone but not by the CYP1A1 variant alone). The interaction index gamma was 2.8, and OR(eg) (95%CI) was 5.0 (1.9-13.4). GSTM1 null genotype and former tobacco smoking were significant in a type 4 interaction model (i.e., the disease risk is increased by GSTM1 null genotype or tobacco exposure alone among the multiplicative effects). The interaction index gamma and OR(eg) (95%CI) were 3.4 and 8.4 (3.4-20.9), respectively. CONCLUSION: Different interaction models of CYP1A1 Val variant allele and GSTM1 null genotype with tobacco smoking will contribute to understanding carcinogenic mechanism, but there is a need to further investigate in larger scale studies.

A novel genetic polymorphism of inducible nitric oxide synthase is associated with an increased risk of gastric cancer.

AIM: Inducible nitric oxide synthase (iNOS) plays a central role in the pathway of reactive oxygen and nitrogen species metabolism when Helicobacter pylori (H pylori) infection occurs in humans. iNOS Ser(608)Leu allele, a novel genetic polymorphism (C/T) occurring within exon 16 of the iNOS reductase domain, may have a dramatic effect on the enzymatic activity. The aim of this study was to determine whether iNOS C/T polymorphism was associated with increased susceptibility to gastric cancer. METHODS: We conducted a population based case-control study in a high gastric cancer incidence area, Yangzhong, China. Questionnaires from 93 patients with intestinal type gastric cancer (IGC), 50 with gastric cardia cancer (GCC) and 246 healthy controls were obtained between 1997 and 1998, and iNOS genotyping was carried out. Odds ratios (ORs), interaction index (gamma), and 95% confidence intervals for the combined effects of iNOS genotype and H pylori infection, cigarette smoking or alcohol drinking were estimated. RESULTS: The frequency of (CT+TT) genotypes was higher in cases than in control group (24.48% vs 23.17%), but the difference was not statistically significant. After adjusting for age and gender, past cigarette smokers with (CT+TT) genotypes had a significantly increased risk of IGC (OR = 3.62, 95% CI: 1.23-10.64), while past alcohol drinkers with (CT+TT) genotypes had a significantly increased risk of GCC (OR = 3.33, 95% CI: 1.14-9.67). H pylori CagA negative subjects with (CT+TT) genotypes had a significantly increased risk of both IGC and GCC (OR = 2.19 and 3.52, respectively). CONCLUSION: iNOS Ser(608)Leu allele may be a potential determinant of susceptibility to cigarette -alcohol induced gastric cancer, but larger studies are needed to confirm the observations.

[Preparation of bispecific monoclonal antibody against HIV p24 and human group A erythrocytes].

AIM: To prepare bispecific monoclonal antibody (bsmAb) against HIV p24 and human group A erythrocytes, and set up an indirect hemagglutination test for detecting HIV p24. METHODS: Hybridoma cells 2-E(4) secreting anti-HIV p24 mAb and hybridoma cells S(2) secreting anti-human group A erythrocyte mAb were naturalized with 8-Ag and 5-BrdU respectively, making them sensitive to HAT. Then the two hybridoma cells sensitive to HAT were fused by routine method and hybrid-hybridoma cells secreting the bsmAb against HIV p24 and human group A erythrocytes were screened. The bsmAb was used to establish an indirect hemagglutination test for detecting HIV p24. RESULTS: 6 hybrid-hybridoma cell lines were obtained. An indirect hemagglutination test for detecting HIV p24 was set up by using the bsmAb, and its sensitivity reached 400 ng/L. CONCLUSION: The bsmAb against HIV p24 and human group A erythrocytes is prepared and a rapid indirect hemagglutination test for detecting HIV p24 is developed by using the purified bsmAb.

Identification of tumor markers using two-dimensional electrophoresis in gastric carcinoma.

AIM: To study the differential expression of proteins in normal and cancerous gastric tissues, and further identify new molecular markers for diagnosis and prognosis of gastric carcinoma, as well as develop new therapeutic targets of the disease. METHODS: Matched pairs of tissues from 6 gastric cancer patients were analyzed for their two-dimensional electrophoresis (2DE) profiles. Soluble fraction proteins from human normal and cancerous gastric tissue were separated in the first dimension by isoelectric focusing on immobilized pH gradient (IPG, pH3-10) strips, and by 125 g/L sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension with silver nitrate staining. Protein differential expression was analyzed by use of image analysis software to find out candidates for gastric cancer-associated proteins. RESULTS: Nine protein spots overexpressed in tumor tissues as compared with noncancerous regions. In the next step, 9 tumor-specific spots were cut off from Coomassie Brilliant Blue staining gels, digested in gel with L-1-tosylamide-2-phenylethyl chloromethyl ketone (TPCK)-trypsin. Protein identification was done by peptide mass fingerprinting with matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). In total, 5 tumor-specific protein spots corresponding to 5 different polypeptide chains were identified, including annexin V, carbonic anhydrase, prohibitin, fibrin beta and fibrinogen fragment D. Among these 5 spots, the potential significance of the differential expressions is discussed. CONCLUSION Differential expression analysis of proteomes may be useful for the development of new molecular markers for diagnosis and prognosis of gastric carcinoma.

[Preparation and characterization of anti-human IL-15 monoclonal antibody].

AIM: To prepare monoclonal antibody (mAb) against human interleukin-15 (hIL-15) and identify its characterization. METHODS: The GST-IL-15 was extracted from the gene-engineering bacteria E. coli and identified by SDS-PAGE. The gel strip containing GST-IL-15 was cut off to immunize BALB/c mice. The splenocytes of immunized mice were fused with Sp2/0 myeloma cells by a routine method and the hybridomas were selected in HAT medium. The hybridoma cells secreting specific antibody were detected by ELISA and cloned by limiting dilution. The stability of the obtained hybridoma cells and the specificity of anti-hIL-15 mAb the hybridoma cells secreted were identified. In addition, the New Zealand rabbits were immunized with the rhIL-15 inclusion body protein (rhIL-15IBP) to prepare the polyclonal antibody (pAb) against hIL-15. A sandwich ELISA was established with the anti-IL-15 mAb and pAb as coating and sandwich antibodies, respectively, to detect hIL-15. RESULTS: One hybridoma cell line which could stably secrete specific mAb was obtained. A sandwich ELISA for detecting rhIL-15 protein was established and its sensitivity was as low as 10 microg/L. CONCLUSION: The anti-hIL-15 mAb was prepared successfully. A sandwich ELISA for the detection of hIL-15 was established.

[The effect of polyporus umbellatus polysaccharide on the immunosuppression property of culture supernatant of S180 cells].

AIM: To investigate the effect of polyporus umbellatus polysaccharide (PUPS) on the immunosuppression property of tumor cell line S180 culture supernatant. METHODS: The inhibitory effects of the culture supernatant of S180 cells in the presence or absence of PUPS on the ConA-induced mouse splenocyte proliferation, IL-2 production, killer activity and the reactivity of CTLL-2 cells to IL-2 were detected by MTT colorimetry. The effect of the culture supernatant on the IL-2Ralpha expression on murine splenocytes was detected by flow cytometry. RESULTS: The culture supernatant of S180 cells could strongly inhibit immunity in terms of the above five indexes, while PUPS could reverse the immunosuppression. CONCLUSION: PUPS can offset the immunosuppression of the supernatant from S180 cell culture, which may be mediated by down-regulating the synthesis and/or secretion of immunosuppressive substance by S180 cells.

Soy and isoflavone consumption in relation to prostate cancer risk in China.

This case-control study in China evaluated the effect of soy food consumption and isoflavones (genistein and daidzein) on the risk of prostate cancer. One hundred and thirty-three cases and 265 age- and residential community-matched controls between the ages of 50 and 89 years were interviewed in person between 1989 and 1992. Usual consumption of soy foods and isoflavones was assessed using a food frequency questionnaire developed in China and a nutrient database developed and validated in Asian-American populations. The age- and total calorie-adjusted odds ratio (OR) of prostate cancer risk comparing the highest tertile of tofu intake to the lowest tertile was 0.58 [95% confidence interval (CI), 0.35-0.96]. There were also statistically significant associations comparing the highest quartile of intake of soy foods (OR, 0.51; 95% CI, 0.28-0.95) and genistein (OR, 0.53; 95% CI, 0.29-0.97) with the lowest quartiles. There was also an indication of a reduced risk associated with intake of daidzein (OR, 0.56; 95% CI, 0.31-1.04 for the highest versus lowest quartile). Our results indicate a reduced risk of prostate cancer associated with consumption of soy foods and isoflavones. These findings should be confirmed in longitudinal follow-up studies in populations with varying risk of prostate cancer.

[Meta-analysis on the epidemiology of Helicobacter pylori infection in China].

OBJECTIVE: To understand the epidemiologic features and etiology of Helicobacter pylori (H. pylori) infection in China so as to provide evidence for the development of preventive measures on H. pylori infection and related diseases. METHODS: Meta-analysis was used to evaluate the data extracted from 1990 - 2002 published papers on the epidemiology of H. pylori infection in China. RESULTS: The average infection rate of H. pylori infection in China was 58.07%, with 50% in 10 to 20 year-olds. Significant intrafamilial clustering was observed. H. pylori infection was a risk factor to develop gastrointestinal disease. CONCLUSIONS: H. pylori infections in Chinese were common and extensively distributed, which might due to close contact between family members.

Helicobacter pylori infection and gastric cancer: evidence from a retrospective cohort study and nested case-control study in China.

AIM: To explore the association between Helicobacter pylori (Hp) infection and risk of gastric cancer in China. METHODS: Utilizing gastroendoscopic biospsy tissue banks accumulated from 1980 to 1988 in Shandong, Zhejiang, and Jiangsu, where stomach cancer incidence was high, during stomach cancer screening conducted by Health Science Center of Peking University, School of Medicine of Zhejiang University, and Zhongshan Hospital of Fudan University. Warthin Starry silver staining method was applied to determine H. pylori infection status of biopsies collected during gastroendoscopic examination. In the retrospective study, the subjects were divided into two cohorts, the exposure cohort was positive H. pylori infection, and the non-exposure cohort was negative. Death from stomach cancer was determined as the outcome of the study. Logistic regression and Cox regression were applied to analyze the association between Helicobacter pylori infection and gastric cancer risk. In the nested case-control study, there were 28 deaths from gastric cancer in the fields of Muping, Shandong province, and Zhoushan, Zhejiang provinces. 4 controls were matched to each case on the basis of age (+/-5 years old), sex, residential place at the same time entered into the study. Conditional logistic regression analysis was used to analyze the data. RESULTS: There were a total of 2 719 subjects (male 1 399, female 1 320) with gastroendoscopic biopsies stored available treated as a cohort. H. pylori positive cohort included 1 671 subjects (61.5 %) and H. pylori negative cohort 1 048 subjects(38.5 %). These subjects were followed up for 1-19 years, averaged 10.88 years. The outcome of death from stomach cancer in the exposure cohort was 33, and in the non-exposure cohort 11. After adjustment for age and sex, RR=1.9850 (P=0.0491), 95 % CI was 1.0026, and 3.9301. The results of conditional logistic regression showed an OR of 4.467 and 95 % CI of 1.161, and 17.190 for the nested case control study. CONCLUSION: The results from the retrospective cohort study and the nested-case control study on the association of H. pylori infection and gastric cancer in China suggested that Helicobacter pylori infection might increase the risk of stomach cancer.

[Extracorporeal experimental study on immuno-modulatory activity of Astragalus memhranaceus extract].

OBJECTIVE: To study the effect of Astragalus membranaceus extract (AME) in regulating the immune function of human peripheral blood immune cells (PBIC) in vitro. METHODS: Effects of AME on the proliferation activity of peripheral blood mononuclear cells (PBMC) and the tumor cell phagocytosis of peripheral blood adherent monocytes (PBAM) were measured by using 3H-TdR incorporation. Effect of the tumor-killing activity of cytotoxic T-lymphocyte (CTL) was determined by using 51Cr-releasing assay. Effects on production of IgG by peripheral blood B cells (PBBC) and IL-6 by PBAM were tested by means of ELISA, and effect on production of TNF-alpha by PBAM was studied by means of biological method. Besides, the protein elements of AME were analysed by SDS-PAGE. RESULTS: AME could promote the proliferation of human PBMC, elevate the tumor cell-killing activity of CTL, strengthen the tumor cell phagocytosis and cytokines (TNF-alpha and IL-6) production of PBAM, and promote the IgG production of PBBC. AME contained multiple protein elements. CONCLUSION: AME has effect in enhancing human immuno-function and anti-tumor activity, it could be applied in clinical practice for immuno-modulation and tumor treatment.