Ubc9 expression predicts chemoresistance in breast cancer / 癌症

Ubiquitin-conjugating enzyme 9 (Ubc9), the sole conjugating enzyme for sumoylation, regulates protein function and plays an important role in tumorigenesis. Whether Ubc9 is involved in the chemoresistance of breast cancer remains unknown. In this study, we aimed to evaluate the contribution of Ubc9 in the chemoresistance of breast cancer. Immunohistochemistry (IHC) was used to examine the expression level of Ubc9. Chi-square test, Wilcoxon test, and one-way ANOVA were applied to analyze the relationship between Ubc9 expression, clinicopathologic features, and clinical response to neoadjuvant chemotherapy. The significance of variables for survival was analyzed by the Cox proportional hazards model in a multivariate analysis. Kaplan-Meier survival curves were plotted and log-rank test was performed. The proportion of Ubc9-positive cells was higher in invasive ductal carcinoma than in normal breast tissues [(48.48 ± 17.94)% vs. (5.82 ± 2.80)%, P < 0.001]. High Ubc9 expression was associated with poor differentiation (Χ² = 6.538, P = 0.038), larger tumor size (Χ² = 4.701, P = 0.030), advanced clinical stage (Χ² = 4.651, P = 0.031), lymph node metastasis (Χ² = 9.913, P = 0.010), basal-like phenotype (Χ² = 8.660, P = 0.034), and poor clinical response to neoadjuvant chemotherapy (Χ² = 11.09, P = 0.001). The expected 6-year cumulative disease-free survival rate was 87.32% in patients with low Ubc9 expression compared to 68.78% in those with high Ubc9 expression (Χ² = 4.289, P = 0.038). These data indicate that high Ubc9 expression correlates with poor response to chemotherapy and poor clinical prognosis.

Preparation of artificial antigen and egg yolk-derived immunoglobulin (IgY) of citrinin for enzyme-linked immunosorbent assay / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To prepare artificial antigens and anti-citrinin egg yolk-derived immunoglobulin (IgY) to build an enzyme-linked immunosorbent assay (ELISA) for citrinin (CTN).</p><p><b>METHODS</b>CTN was conjugated with bovine serum albumin (BSA), ovalbumin (OVA) with formaldehyde condensation method to prepare artificial antigens and identified by ultraviolet (UV) spectrometry and Infrared (IR) spectrometry. Artificial antigens for CTN and anti-CTN IgY were purified with polyethylene glycol two-step precipitation method and identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). ELISA with IgY was established. Cross-reactivity of IgY with various structural similarities to CTN and possible co-occurrence with CTN in agricultural commodities were studied.</p><p><b>RESULTS</b>UV and IR absorption spectra suggested that CTN was correlated with the carrier protein of BSA or OVA. SDS-PAGE patterns showed that the anti-CTN IgY was almost pure with a molecular weight of approximate 100 KD. The indirect competitive ELISA showed that the detection limit of CTN was 10 ng x mL(-1), with a good linearity ranging 20-640 ng x mL(-1).</p><p><b>CONCLUSION</b>Artificial antigens of CTN can be successfully synthesized. The established ELISA can be used to determine CTN- contaminated samples.</p>

Analysis of microRNA in drug-resistant breast cancer cell line MCF-7/ADR / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the difference in microRNAs expression between MCF-7 and MCF-7/ADR cells and explore the association between microRNA and drug resistance of breast cancer.</p><p><b>METHODS</b>The drug resistance of MCF-7/ADR cells was evaluated using MTT assay and flow cytometry. Microarray technique and RT-PCR were used to analyze the differential expressions of the microRNA between MCF-7 and MCF-7/ADR cells.</p><p><b>RESULTS</b>The drug resistance index of MCF-7/ADR cells relative to the parental MCF-7 cells was 33.2. The percentages of the side population in MCF-7/ADR and MCF-7 cells were (9.50-/+0.9)% and (0.85-/+0.2)%, respectively. Microarray analysis of MCF-7 to MCF-7/ADR cells identified 36 differentially expressed genes, including 16 up-regulated and 20 down-regulated genes in MCF-7/ADR cells. RT-PCR identified 14 microRNAs that were differentially expressed between MCF-7 and MCF-7/ADR cells, including 7 up-regulated and 7 down-regulated ones in MCF-7/ADR cells. Of these differentially expressed microRNAs, mir-221, mir222, mir-130a, and mir-155 showed significantly increased expression, and mir200a, mir-200b, mir-200c, and mir-421 showed significantly lowered expression in MCF-7/ADR cells as indicated by the results of microarray analysis and RT-PCR.</p><p><b>CONCLUSION</b>MCF-7/ADR cells show a different microRNA expression profile from its parental MCF-7 cells, suggesting the involvement of microRNAs in tumor cell drug resistance. This finding provides a experimental basis for further study of mechanism underlying the drug resistance of breast cancer.</p>

Alternatively activated macrophages/mononuclear phagocytes promote growth and invasion of breast cancer cell line SKBR3 / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of alternatively activated macrophages /mononuclear phagocytes(MNP) on breast cancer cells and explore the mechanisms for the action of tumor-associated macrophages in breast cancer.</p><p><b>METHODS</b>Human peripheral blood monocytes were isolated and cultured in vitro and divided into 3 groups, namely classically activated monocytes (CAM) which were induced by lipopolysaccharide, alternatively activated monocytes (AAM) induce by IL-4, and control cells treated with the culture medium only. After cell culture for 48-72 h, the mRNA of tumor necrosis factor-alpha (TNF-alpha), alternative monocytes activation- associated CC-chemokine 1 (AMAC-1), and beta-actin of the 3 groups were extracted for RT-PCR, or the cells were cocultured with breast cancer cell line SKBR3, or seeded in chicken chorioallantoic membrane along with SKBR3.</p><p><b>RESULTS</b>TNF-alpha mRNA was significantly increased in CAM, and AMAC-1 was highly expressed in AAM. The coculture experiments showed that CAM exhibited obvious inhibitory effect on SKBR3 cells after a 3-day culture whereas AAM significantly promoted the growth of SKBR3 cells after a 5-day culture. In chicken on chorioallantoic membrane experiment, the macrophages promoted tumor angiogenesis and AAM showed the most obvious effect.</p><p><b>CONCLUSION</b>IL-4 induces high expression of AMAC-1, a molecular marker of AAM, in the macrophages, and AAM can promote the growth of SKBR3 cells and tumor angiogenesis.</p>

Vector-mediated HER-2 RNA interference against HER-2-positive breast cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the feasibility of vector-mediated RNA interference for HER-2-positive breast cancer therapy.</p><p><b>METHODS</b>A plasmid vector capable of mediating HER-2 RNA interference was constructed, and HER-2-positive breast cancer cell line SKBR-3 was transfected with this constructed vector. The expression of HER-2 mRNA and protein was analyzed by RT-PCR and Western blotting, and the growth and apoptosis of SKBR-3 cells was analyzed after transfection.</p><p><b>RESULTS</b>The expressions of HER-2 mRNA and HER-2 protein was downregulated in response to vector-mediated HER-2 RNA interference, which also resulted in tumor cell growth inhibition and increased number apoptotic cells.</p><p><b>CONCLUSION</b>HER-2 is a good target for RNA interference and RNA interference targeting HER-2 can lead to HER-2 breast cancer cell apoptosis and growth inhibition.</p>

Relationship between COX-2 expression and clinicopathological features of colorectal cancers / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cyclo-oxgenase 2 (COX-2) is involved in prostaglandin synthesis in central nervous system, and it also plays a role in human carcinogenesis. Our purpose of this study is to investigate the COX-2 expression in different development stages of colorectal cancer, and to discuss the relationship between the gene expression and clinicopathological features of the cancer.</p><p><b>METHODS</b>COX-2 expression was examined by immunohistochemical staining in 76 surgical specimens of colorectal cancer (44 of advanced stage and 32 of early stage), thirty-three adenomas and 18 normal colonic mucosal tissues taken by endoscopic biopsy. Kaplan-Meier survival curves and Cox proportional hazards regression were used to evaluate the relation of COX-2 to prognosis.</p><p><b>RESULTS</b>COX-2 expression, divided into 4 grades from "-" to "+++", is respectively 83.3%, 16.7%, 0% and 0% in normal colonic mucosal tissues; 12.1%, 42.4%, 36.4% and 9.1% in adenomas; 6.3%, 28.1%, 46.9% and 18.7% in early colorectal cancers (ECCs), and 6.8%, 20.5%, 18.2% and 54.5% in advanced colorectal cancers (CRCs). The differences in COX-2 expression between advanced CRCs and early colorectal cancers (ECCs) as well as between the advanced CRCs and adenomas were statistically significant (P < 0.01); but there was no significant difference between ECCs and adenomas. Kaplan-Meier survival analysis showed a significant difference in the survival curves between low high COX-2 groups (P < 0.05). Cox proportional hazards regression showed that COX-2 expression was related to poorer long-term outcome with a hazard ratio of 2.665 unadjusted for other variables (P < 0.05), and COX-2 expression was an independent risk factor of poor prognosis.</p><p><b>CONCLUSIONS</b>COX-2 expression is gradually up-regulated in the development from normal epithelium to adenomas and from ECCs to advanced CRCs. Alhough the COX-2 protein can not be regarded as a tumor marker to diagnose CRCs early, COX-2 expression can be regarded as an independent risk factor of poor prognosis for postoperative patients with advanced CRCs.</p>