Application of gene expression profiling for validating models of human breast cancer

While classical histopathologic approaches are invaluable in classifying tumors and understanding aspects of cellular interactions, genomic approaches provide a means to molecularly dissect tumorigenesis. The relationship of gene expression to the development of neoplasia remains an area of intensive research. With the advent of large-scale genomic platforms, alterations in gene expression can be related to the morphological development of cancer. The feasibility of using large-scale genomic analysis platforms has dramatically changed the landscape of biological sciences, as cellular processes must be considered in the context of complex networks. Alterations in gene expression must now be understood in a systems approach in which the relationships between genes expression changes are studied by considering the interplay of multiple regulatory networks. Ultimately, such changes must be understood at the protein level. We have begun to apply this technology to determine changes in gene expression that differentiate various types of mammary cancers that arise in mouse models that have been initiated by different genetic alterations. Ultimately, a molecular catalogue of similarities and differences between rodent and human tumors can be created which will serve to validate or credential particular models for specific experimental purposes, such as preclinical testing. These approaches have led to new insights into molecular pathways involved in oncogenesis, new classifications of human breast cancer, and the identification of new genes that may be relevant to understanding and treating human cancer.     

Bcl2-L-10, a novel anti-apoptotic member of the Bcl-2 family, blocks apoptosis in the mitochondria death pathway but not in the death receptor pathway.

By GenBank database searches and PCR, we have identified a novel human Bcl2-like gene, Bcl2-L-10, which contains conserved BH4, BH1 and BH2 domains but lacks BH3 domain. The Bcl2-L-10 gene has been assigned to chromosome 15q21.2. Transfection experiments demonstrated that Bcl2-L-10 can block apoptosis induced by interleukin-3 withdrawal and Bax expression, by prevention of cytochrome C release, caspase-3 activation and mitochondrial membrane potential collapse. Bcl2-L-10 cannot block TNFalpha-induced apoptosis. Furthermore, both the BH4 domain and the transmembrane domain of Bcl2-L-10 are necessary for its suppressive action on cell death. Our results demonstrated that Bcl2-L-10 is a newly detected anti-apoptotic member of the Bcl-2 family and that it blocks apoptosis in the mitochondrial death pathway but not in the death receptor pathway.     

利用原位杂交分析几种cyclin和CDK基因在人乳腺癌中的异常表达

目的 探讨细胞周期调控基因ｃｙｃｌｉｎ和ＣＤＫ的异常与乳腺癌发生的相关性。方法 采集２０例乳腺癌外科手术样品,用原位杂交技术分析了ｃｙｃｌｉｎ Ｄ１,Ｄ３,Ｅ,ＣＤＫ２和ＣＤＫ４ｍＲＮＡ的表达。结果 在大多数乳腺癌样品中,这些基因有一种或几种出现高表达。     

AAC-11 overexpression induces invasion and protects cervical cancer cells from apoptosis

To identify the genes involved in cervical carcinogenesis, we applied the mRNA differential display (DD) method to analyze normal cervical tissue, cervical cancer, metastatic lymph node, and cervical cancer cell line. We cloned a 491-bp cDNA fragment, CC231, which was present in metastatic tissue and cervical cancer cell line, but absent in normal cervical and cervical cancer tissues. The 491 bp cDNA fragment has 98% homology to the previously published sequence, AAC-11 (antiapoptosis clone 11). The levels of AAC-11 mRNA expressions in nine normal cervical and nine primary cervical cancer tissues were low. Its expression was higher in three metastatic tissues and five cervical cancer cell lines (HeLa, CaSki, SiHa, CUMC-3, and CUMC-6). Invasion of matrigel and adhesion to laminin by AAC-11 transfected CUMC-6 cells were increased by approximately 2-fold and 4-fold, respectively. Northern blot analysis showed that matrix metalloproteinase (MMP)-2 and membrane type 1 MMP (MT1-MMP) genes were found to be expressed in high levels in AAC-11-transfected cancer cells. But MMP-2 and MT1-MMP were not expressed in cells transfected with vector alone or wild-type cells. AAC-11-transfected cells expressed an elevated level of MMP-2 protein as assessed by immunoblotting. On the contrary, tissue inhibitor of MMP (TIMP-2) expression was detectable in cells transfected with vector alone or wild-type cells, respectively. Its expression was undetectable in AAC-11 transfected cells. In cervical cancer cells transfected with AAC-11, the expression of beta-catenin was up-regulated. These suggest that overexpressions of MMP-2 and MT1-MMP, loss of TIMP-2 expression, and up-regulation of beta-catenin by AAC-11 transfection may contribute to the development of cervical cancer invasion. AAC-11 gene transfection increased cervical cancer cell colonization. The effect of AAC-11 on cultured cervical cancer cells was associated with antiapoptotic process. Approximately 50% of the AAC-11 transfected cells in serum-free medium died after 2 weeks, compared to 1 week for vector alone or wild-type cells. These results suggest that AAC-11 may serve as a candidate metastasis-related and apoptosis-inhibiting gene in human cervical cancer.     

Bcl‐3 induced by IL‐22 via STAT3 activation acts as a potentiator of psoriasis‐related gene expression in epidermal keratinocytes

IL‐22 induces STAT3 phosphorylation and mediates psoriasis‐related gene expression. However, the signaling mechanism leading from pSTAT3 to the expression of these genes remains unclear. We focused on Bcl‐3, which is induced by STAT3 activation and mediates gene expression. In cultured human epidermal keratinocytes, IL‐22 increased Bcl‐3, which was translocated to the nucleus with p50 via STAT3 activation. The increases in CXCL8, S100As and human β‐defensin 2 mRNA expression caused by IL‐22 were abolished by siRNA against Bcl‐3. Although CCL20 expression was also augmented by IL‐22, the knockdown of Bcl‐3 increased its level. Moreover, the combination of IL‐22 and IL‐17A enhanced Bcl‐3 production, IL‐22‐induced gene expression, and the expression of other psoriasis‐related genes, including those encoding IL‐17C, IL‐19, and IL‐36γ. The expression of these genes (except for CCL20) was also suppressed by the knockdown of Bcl‐3. Bcl‐3 overexpression induced CXCL8 and HBD2 expression but not S100As expression. We also compared Bcl‐3 expression between psoriatic skin lesions and normal skin. Immunostaining revealed strong signals for Bcl‐3 and p50 in the nucleus of epidermal keratinocytes from psoriatic skin. The IL‐22‐STAT3‐Bcl‐3 pathway may be important in the pathogenesis of psoriasis.     

P53融合蛋白的原核表达及其单克隆抗体的制备

目的 为研制出能特异与Ｐ＾５３结合的单克隆抗体,使对Ｐ＾５３的检测得到更为广泛的应用。方法 用ＰＣＲ技术扩增编码人Ｐ＾５３Ｎ－端１８０个氨基酸的ＤＮＡ片段并将其克隆在谷胱苷肽转移酶（ＧＳＴ）表达质粒Ｐ＾ＧＥＸ－２Ｔ中。用该重组质粒转化大肠杆菌ＪＭ１０９,并经异丙基β－Ｄ硫代半乳糖苷（ＩＰＴＧ）诱导产生Ｐ＾５３－ＧＳＴ融合蛋白。用Ｐ＾５３－ＧＳＴ免疫ＢＡＬＢ／ｃ小鼠。常规细胞融合,间接酶联免疫吸附试     

Aberrant expression of p53 gene product in malignant melanoma.

According to the current concept of carcinogenesis, the alterations of p53 tumor suppressor gene have been the most frequently detected in both human cancer cell lines and cancer tissues freshly isolated. This study was conducted to investigate the p53 gene alteration in malignant melanoma. Nineteen tumor tissues were obtained from 19 patients with malignant melanoma and examined for the expression of p53 protein by immunohistochemical staining with mouse monoclonal anti-p53 antibody, NCL-p53-DO-7. Twelve out of 19 cases (63%) showed positive reactions for p53 protein: 26, 21 and 16% of which had low, intermediate and high reactivity, respectively. p53 alteration more frequently expressed in female (10/12) than male patients (2/7) with malignant melanoma (p < 0.05). The incidence of expression of p53 protein was compared according to the stages and the sites of tissue obtained. The positive rate for p53 protein was not significantly different between the stages. The positive rates for p53 protein were five out of five (100%), one out of two (50%) and six out of twelve (50%) in tissues obtained from the metastatic, lymph node, and primary sites, respectively. The difference in the positive rates, however, is not statistically significant. These results suggest that p53 gene is a frequent target for mutation in the development of malignant melanoma.     

Osteopontin is up-regulated and associated with neutrophil and macrophage infiltration in glioblastoma

Osteopontin (OPN) is a glycophosphoprotein with multiple intracellular and extracellular functions. In vitro, OPN enhances migration of mouse neutrophils and macrophages. In cancer, extracellular OPN facilitates migration of cancer cells via its RGD sequence. The present study was designed to investigate whether osteopontin is responsible for neutrophil and macrophage infiltration in human cancer and in particular in glioblastoma. We found that in vitro mouse neutrophil migration was RGD‐dependent. In silico, we found that the OPN gene was one of the 5% most highly expressed genes in 20 out of 35 cancer microarray data sets in comparison with normal tissue in at least 30% of cancer patients. In some types of cancer, such as ovarian cancer, lung cancer and melanoma, the OPN gene was one of those with the highest expression levels in at least 90% of cancer patients. In glioblastoma, the most invasive type of brain tumours/glioma, but not in lower grades of glioma it was one of the 5% highest expressed genes in 90% of patients. In situ, we found increased protein levels of OPN in human glioblastoma versus normal human brain confirming in silico results. OPN protein expression was co‐localized with neutrophils and macrophages. In conclusion, OPN in tumours not only induces migration of cancer cells but also of leucocytes.     

Molecular characterization of human breast tumor vascular cells

A detailed understanding of the assortment of genes that are expressed in breast tumor vessels is needed to facilitate the development of novel, molecularly targeted anti-angiogenic agents for breast cancer therapies. Rapid immunohistochemistry using factor VIII-related antibodies was performed on sections of frozen human luminal-A breast tumors (n = 5) and normal breast (n = 5), followed by laser capture microdissection of vascular cells. RNA was extracted and amplified, and fluorescently labeled cDNA was synthesized and hybridized to 44,000-element long-oligonucleotide DNA microarrays. Statistical analysis of microarray was used to compare differences in gene expression between tumor and normal vascular cells, and Expression Analysis Systematic Explorer was used to determine enrichment of gene ontology categories. Protein expression of select genes was confirmed using immunohistochemistry. Of the 1176 genes that were differentially expressed between tumor and normal vascular cells, 55 had a greater than fourfold increase in expression level. The extracellular matrix gene ontology category was increased while the ribosome gene ontology category was decreased. Fibroblast activation protein, secreted frizzled-related protein 2, Janus kinase 3, and neutral sphingomyelinase 2 proteins localized to breast tumor endothelium as assessed by immunohistochemistry, showing significantly greater staining compared with normal tissue. These tumor endothelial marker proteins also exhibited increased expression in breast tumor vessels compared with that in normal tissues. Therefore, these genetic markers may serve as potential targets for the development of angiogenesis inhibitors.     

Database of mRNA gene expression profiles of multiple human organs

Genome-wide expression profiling of normal tissue may facilitate our understanding of the etiology of diseased organs and augment the development of new targeted therapeutics. Here, we have developed a high-density gene expression database of 18,927 unique genes for 158 normal human samples from 19 different organs of 30 different individuals using DNA microarrays. We report four main findings. First, despite very diverse sample parameters (e.g., age, ethnicity, sex, and postmortem interval), the expression profiles belonging to the same organs cluster together, demonstrating internal stability of the database. Second, the gene expression profiles reflect major organ-specific functions on the molecular level, indicating consistency of our database with known biology. Third, we demonstrate that any small (i.e., n approximately 100), randomly selected subset of genes can approximately reproduce the hierarchical clustering of the full data set, suggesting that the observed differential expression of >90% of the probed genes is of biological origin. Fourth, we demonstrate a potential application of this database to cancer research by identifying 19 tumor-specific genes in neuroblastoma. The selected genes are relatively underexpressed in all of the organs examined and belong to therapeutically relevant pathways, making them potential novel diagnostic markers and targets for therapy. We expect this database will be of utility for developing rationally designed molecularly targeted therapeutics in diseases such as cancer, as well as for exploring the functions of genes.     

Tumor suppressive microRNA-133a regulates novel molecular networks in lung squamous cell carcinoma

Analysis of the microRNA (miRNA) expression signature of lung squamous cell carcinoma (lung-SCC) revealed that the expression levels of miR-133a were significantly reduced in cancer tissues compared with normal tissues. In this study, we focused on the functional significance of miR-133a in cancer cell lines derived from lung-SCC and the identification of miR-133a-regulated novel cancer networks in lung-SCC. Restoration of miR-133a expression in PC10 and H157 cell lines resulted in significant inhibition of cell proliferation, suggesting that miR-133a functions as a tumor suppressor. We used genome-wide gene expression analysis to identify the molecular targets of miR-133a regulation. Gene expression data and web-based searching revealed several candidate genes, including transgelin 2 (TAGLN2), actin-related protein2/3 complex, subunit 5, 16kDa (ARPC5), LAG1 homolog, ceramide synthase 2 (LASS2) and glutathione S-transferase pi 1 (GSTP1). ARPC5 and GSTP1 likely represent bona fide targets as their expression is elevated in lung-SCC clinical specimens. Furthermore, transient transfection of miR-133a, repressed ARPC5 and GSTP1 mRNA and protein levels. As cell proliferation was significantly inhibited in lung-SCC cells following RNAi knock down of either gene, ARPC5 and GSTP1 may function as oncogenes in the development of lung-SCC. The identification of a tumor suppressive miRNA and the novel cancer pathways it regulates could provide new insights into potential molecular mechanisms of lung-SCC carcinogenesis.     

Human gastric cancer kinase profile and prognostic significance of MKK4 kinase

Alterations of protein tyrosine kinase are often associated with uncontrolled cell growth and tumor progression. Knowledge of the overall expression pattern of tyrosine kinases should prove beneficial in understanding the signaling pathways involved in gastric cancer oncogenesis and in providing possible biomarkers for gastric cancer progression. To establish a general tyrosine-kinase expression profile, degenerated polymerase chain reaction primers designed from the consensus catalytic kinase motifs were used to amplify protein tyrosine kinase molecules from gastric cancer tissues. We observed more than 50 tyrosine and serine/threonine kinases from matching pairs of gastric cancer tissue and normal mucosa. Based on this new kinase profile information, we selected the MKK4 gene for further immunohistochemical studies. Statistical analysis of MKK4 protein expression and clinicopathological features indicated that MKK4 kinase expression could serve as a significant prognostic factor for relapse-free survival and for overall survival. We demonstrated a simple and sensitive method for establishing protein tyrosine-kinase expression profiles of human gastric cancer tissues as well as for discovering novel and useful clinical biomarkers from such kinase expression profiles.