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The epithelium of the adult prostate contains 3 distinct cell types: basal, luminal, and neuroendocrine. Tissue-regenerative activity has been identified predominantly from the basal cells, isolated by expression of CD49f and stem cell antigen-1 (Sca-1). An important question for the field is whether all basal cells have stem cell characteristics. Prostate-specific microarray databases were interrogated to find candidate surface antigens that could subfractionate the basal cell population. Tumor-associated calcium signal transducer 2 (TACSTD2/Trop2/M1S1/GA733-1) was identified because it was enriched after castration, in prostate sphere cells and in the basal fraction. In the murine prostate, Trop2 shows progenitor characteristics such as localization to the region of the gland proximal to the urethra and enrichment for sphere-forming and colony-forming cells. Trop2 subfractionates the basal cells into 2 populations, both of which express characteristic basal cell markers by quantitative PCR. However, only the basal cells expressing high levels of Trop2 were able to efficiently form spheres in vitro. In the human prostate, where Sca-1 is not expressed, sphere-forming progenitor cells were also isolated based on high expression of Trop2 and CD49f. Trop2-expressing murine basal cells could regenerate prostatic tubules in vivo, whereas the remaining basal cells had minimal activity. Evidence was found for basal, luminal, and neuroendocrine cells in prostatic tubules regenerated from ${\\rm Trop}2^{{\\rm hi}}$ basal cells. In summary, functionally distinct populations of cells exist within the prostate basal compartment and an epithelial progenitor can give rise to neuroendocrine cells in vivo.

Colorectal cancer (CRC), one of the most prevalent malignant cancers, has high rates pf incidence and is the fourth leading cause of cancer-related deaths for both men and women worldwide. MicroRNAs (miRNAs) play critical roles in the development of various types of cancers. miRNA-330-5p has been implicated in the progression of prostate, neuronal and pancreatic cancers by regulating proliferation, migration, invasion and epithelial-mesenchymal transition of cells. The purpose of the present study was to investigate the expression of miR-330-5p in CRC and identify its target gene(s) that may act in CRC tumorigenesis. We found that miR-330-5p expression was significantly lower in CRC tissues than that in adjacent non-tumorous tissues. Furthermore, we identified integrin α5 (ITGA5) as a new target of miR-330-5p and found that it inhibits ITGA5 expression by directly binding to the 3′ untranslated region of ITGA5 mRNA. These results suggest that downregulation of miR-330-5p expression may affect CRC development via modulation of ITGA5 expression.

ObjectiveTo study integrin α6 expression in lung adenocarcinoma tissue through comparison with matching adjacent non-cancerous tissues as well as elucidating the correlation between integrin α6 expression with the clinical parameters of lung adenocarcinoma. We also explore the signal pathways associated with integrin α6 up-regulation.MethodsThe clinical data, cancer tissues, and adjacent non-cancerous tissues of 30 patients diagnosed with lung adenocarcinoma were collected from Taizhou Hospital in Zhejiang Province, China, in 2010. The protein levels of integrin α6 were determined by immunohistochemistry methods. mRNA data of 85 lung adenocarcinoma tissues and 14 normal tissues as well as clinical results were collected from GEO30219. We also collected mRNA data of 533 lung adenocarcinoma tissues and 59 normal tissues as well as the clinical results of 522 patients with lung adenocarcinoma from the Cancer Genome Atlas (TCGA) database. The differences in protein and mRNA levels in cancer tissues and non-cancerous tissues were analyzed, and we subsequently investigated the association between integrin α6 expression and key parameters indicating lung adenocarcinoma progression and overall survival rate. Additionally, the possible pathways involved in the up-regulation of integrin α6 were analyzed by GSEA.ResultsThe protein levels of integrin α6 in lung adenocarcinoma tissues were significantly higher than those in adjacent tissues (p < 0.01), and were positively correlated with the grade and T stage of lung adenocarcinoma (p < 0.05). Patients with low integrin α6 protein levels had higher survival rates (p < 0.05). The analysis of gene chip data from the TCGA database also showed that the integrin α6 mRNA level was significantly correlated with T stage (p < 0.05), overall survival (OS) rate (p < 0.01), and disease-free survival (DFS) rate (p = 0.005). GSEA gene enrichment analysis identified a series of pathways that may be associated with integrin α6 up-regulation, including the AGR, PYK2, ECM, and PTEN pathways.ConclusionIntegrin α6 plays an important role in the occurrence and progression of lung adenocarcinoma and may act as a prognostic predictor of lung adenocarcinoma in patients. Based on the results of the present study, integrin α6 may be a potential target gene for the treatment of lung adenocarcinoma.

Accumulating evidence supports cancer to initiate and develop from a small population of stem-like cells termed as cancer stem cells (CSC). The exact phenotype of CSC and their counterparts in normal mammary gland is not well characterized. In this study our aim was to evaluate the phenotype and function of stem/progenitor cells in normal mammary epithelial cell populations and their malignant counterparts. Freshly isolated cells from both normal and malignant human breasts were sorted using 13 widely used stem/progenitor cell markers individually or in combination by multi-parametric (up to 9 colors) cell sorting. The sorted populations were functionally evaluated by their ability to form colonies and mammospheres, in vitro. We have compared, for the first time, the stem/progenitor markers of normal and malignant breasts side-by-side. Amongst all markers tested, we found CD44high/CD24low cell surface marker combination to be the most efficient at selecting normal epithelial progenitors. Further fractionation of CD44high/CD24low positive cells showed that this phenotype selects for luminal progenitors within Ep-CAMhigh/CD49f + cells, and enriches for basal progenitors within Ep-CAM-/low/CD49f + cells. On the other hand, primary breast cancer samples, which were mainly luminal Ep-CAMhigh, had CD44high/CD24low cells among both CD49fneg and CD49f + cancer cell fractions. However, functionally, CSC were predominantly CD49f + proposing the use of CD44high/CD24low in combination with Ep-CAM/CD49f cell surface markers to further enrich for CSC. Our study clearly demonstrates that both normal and malignant breast cells with the CD44high/CD24low phenotype have the highest stem/progenitor cell ability when used in combination with Ep-CAM/CD49f reference markers. We believe that this extensive characterization study will help in understanding breast cancer carcinogenesis, heterogeneity and drug resistance.

Background CD151, c-Met, and integrin alpha3/alpha6 are all involved in the hepatocyte growth factor (HGF)/c-Met signal pathway, which plays an important role in the malignant progression of tumors. Aims The purpose of this study was to explore the expression and prognostic significance of these proteins in pancreatic ductal adenocarcinoma (PDAC). Methods We used immunohistochemical methods to investigate the expression patterns of CD151, c-Met, and integrin alpha3/alpha6proteins in 71 patients with PDAC and in ten samples of normal pancreatic tissue. We also assessed correlations between these proteins and clinicopathological parameters and survival of PDAC patients using various statistical methods. Results CD151, c-Met, and integrin alpha3/alpha6 were all overexpressed in PDAC. CD151 and c-Met overexpressions were significantly associated with TNM stage ( p  = 0.001 and p  = 0.038, respectively) and lymph node invasion ( p  = 0.000, p  = 0.012, respectively). A significant positive linear correlation was found between CD151 and c-Met ( r  = 0.583; p  = 0.000), integrin alpha3 ( r  = 0.457; p  = 0.000), and integrin alpha6 ( r  = 0.671; p  = 0.000). Overexpression of CD151, c-Met, integrin alpha3, or integrin alpha6 was related to poor survival of PDAC patients ( p  = 0.000, p  = 0.000, p  = 0.005, and p  = 0.003, respectively), and CD151 and c-Met were independent factors in prognosis of PDAC. Conclusions CD151, c-Met, and integrin alpha3/alpha6 were all overexpressed in PDAC. CD151 and c-Met might be new molecular markers to predict the prognosis of PDAC patients.

Background The aim of this study was to elucidate the value of putative cancer stem cell markers Musashi-1, ALDH1, Sox2, and CD49f in predicting the prognosis in cervical squamous cell carcinoma (CSCC). Methods Real-time PCR and immunohistochemistry staining was performed to examine Musashi-1, ALDH1, Sox2, and CD49f expression in archived specimens of CSCC patients with postoperative chemotherapy. Kaplan–Meier analysis and Cox proportional hazards model were used to assess the prognostic impact of CSC markers for overall survival (OS) and recurrent-free survival (RFS). Results The Real-time PCR data showed that the expression of all markers were increased in CSCC tissues compared with in paired normal cervical tissues ( P  < 0.05). The IHC result showed that high expression of Msi1, ALDH1, Sox2, and CD49f was found in 25.7 %, 43.0 %, 62.0 % and 29.0 % CSCC samples, respectively. Moreover, high expression of Msi1 ( P  = 0.033 and P  = 0.003, respectively), ALDH1 ( P  = 0.015 and P  = 0.002, respectively), and Sox2 ( P  = 0.005 and P  = 0.003, respectively), and low expression of CD49f ( P  = 0.027 and P  = 0.025, respectively) were correlated with poor OS and PFS in CSCC patients. Interestingly, tumors with Msi1 high /CD49f low expression had the poorest prognosis according to Msi1/CD49f stratification. In multivariate Cox regression analysis, Sox2 expression ( P  = 0.047 and P  = 0.018, respectively), ALDH1 expression ( P  = 0.013 and P  = 0.003, respectively), and CD49f expression ( P  = 0.008 and P  = 0.003, respectively) were independent prognostic markers for both OS and RFS. Conclusions Our results suggest that cancer stem cell markers are linked with poor prognosis of CSCC patients.

Integrins play an important role in cellular matrix interactions requisite for cancer cell adhesion, growth, migration and invasion. In this study, we have investigated the expression of integrin subunits alpha3, alpha6, alphav and beta1 in normal ovaries, benign ovarian tumors and ovarian carcinomas of different pathological grades. The expression of these integrins in ovarian cancer cell lines was also investigated, and their role in sustaining proliferation, adhesion, migration and invasion in cohort with the activation of signaling pathways in response to extracellular matrices (ECM) was evaluated. We demonstrate a differential expression pattern of alpha3, alpha6, alphav and beta1 integrin subunits in ovarian carcinomas compared to normal ovaries and benign ovarian tumors. Ovarian cancer cell lines (Hey, Ovcar3 and Peo.36) demonstrated significantly high expression of alpha3, alpha6, alphav and beta1 integrin subunits. A significant increase in proliferation and adhesion (P<0.05) in response to collagen 1 (Coll) and laminin (LM), ligands for integrin receptor alpha3beta1 and alpha6beta1 was observed in ovarian cancer cell lines. On the other hand, fibronectin (FN), a receptor for alphavbeta1 integrin, increased proliferation in all ovarian cancer cell lines studied but only enhanced adhesion in Hey cell line (P<0.05). Neutralizing antibodies against alpha3, alpha6, alphav and beta1 integrin subunits inhibited ECM-induced proliferation, but increased adhesion to ECM was inhibited by beta1 integrin subunit antibody. No suppression of Coll, LM and FN-induced (Hey cells only) adhesion was observed in the presence of alpha3 or alphav subunit antibodies but LM-induced adhesion was inhibited by blocking alpha6 subunit functions. LM, FN and Coll enhanced chemotactic migration in Hey cells, but direct invasion across ECM was observed only in the presence of LM and Coll. Blocking antibodies against alpha3, alpha6 and beta1 integrin subunits inhibited both chemotactic migration and invasion of Hey cells in response to respective ECM. Adhesion of ovarian cancer cells to FN, Coll and LM activated Ras, Erk and Akt pathways. Neutralizing alphav and beta1 functions did not inhibit FN-induced activation of Ras and Erk pathways but inhibited the Akt pathway. On the other hand, antibodies against alpha6 and beta1 subunits, but not alpha3 subunit, inhibited LM-induced activation of Ras but did not inhibit the downstream Akt pathway. Neutralizing beta1 subunit function however, inhibited LM-induced Erk activation. Coll-induced activation of Ras, Erk and Akt pathways was inhibited by alpha3 and beta1 integrin subunit antibodies. These results indicate that alpha3beta1, alphavbeta1 and alpha6beta1 integrin mediate proliferation, adhesion, migration and invasion of ovarian cancer cells in response to ECM and targeting these integrins to modulate integrin-ECM interactions in tumor cells may be a promising tool to reduce the dissemination of ovarian carcinoma in vivo.

Background: Albumin is known to induce chemokinesis and facilitate chemotaxis of human granulocytes in the Boyden chamber assay, but its mechanisms of action remain obscure. We have previously found that IL-2 inhibits albumin-stimulated eosinophil migration. The aim of this study was to identify the mechanisms behind the effects of albumin and IL-2 on the migration of human eosinophils. Methods: Purified eosinophils were preincubated with inhibitors of signal transduction molecules before incubation with or without albumin and IL-2. The migration assay was performed in a 48-well microchemotaxis chamber. The effect of albumin and IL-2 on cell size and on the surface expression of adhesion molecules was studied with flow cytometry. Results: Albumin-stimulated migration was inhibited by the PI3-kinase inhibitors wortmannin and LY-294002, but not by the PKC inhibitor RO-31-8220. IL-2 had no effect after preincubation with wortmannin or LY-294002. In contrast, the inhibitory effect of IL-2 remained after preincubation with RO-31-8220. Albumin increased the cell size as measured by forward scatter, and the expression of CD49d and CD49f decreased after incubation with albumin. IL-2 affected neither the expression of adhesion molecules nor the forward scatter. Conclusions: The stimulation of eosinophil migration by albumin is mediated by PI3-kinase, and the increase in cell size caused by albumin indicates activation of the cells. Decreased expression of CD49d and CD49f by albumin may diminish the adhesiveness of the cells, which in turn may facilitate migration. These are novel findings that indicate an active role for albumin in eosinophil migration.

The α6 integrin subunit (α6) has been implicated in cancer cell migration and in the progression of several malignancies, but its role in tumor angiogenesis is unclear. In mice, anti-α6 blocking antibodies reduce tumor angiogenesis, whereas Tie1-dependent α6 gene deletion enhances neovessel formation in melanoma and lung carcinoma. To clarify the discrepancy in these results we used the cre-lox system to generate a mouse line, α6fl/fl-Tie2Cre+, with α6 gene deletion specifically in Tie2-lineage cells: endothelial cells, pericytes, subsets of hematopoietic stem cells, and Tie2-expressing monocytes/macrophages (TEMs), known for their proangiogenic properties. Loss of α6 expression in α6fl/fl-Tie2Cre+ mice reduced tumor growth in a murine B16F10 melanoma model. Immunohistological analysis of the tumors showed that Tie2-dependent α6 gene deletion was associated with reduced tumor vascularization and with reduced infiltration of proangiogenic Tie2-expressing macrophages. These findings demonstrate that α6 integrin subunit plays a major role in tumor angiogenesis and TEM infiltration. Targeting α6 could be used as a strategy to reduce tumor growth.

The normal function of Syk in epithelium of the developing or adult breast is not known, however, Syk suppresses tumor growth, invasion, and metastasis in breast cancer cells. Here, we demonstrate that in the mouse mammary gland, loss of one Syk allele profoundly increases proliferation and ductal branching and invasion of epithelial cells through the mammary fat pad during puberty. Mammary carcinomas develop by one year. Syk also suppresses proliferation and invasion in vitro. siRNA or shRNA knockdown of Syk in MCF10A breast epithelial cells dramatically increased proliferation, anchorage independent growth, cellular motility, and invasion, with formation of functional, extracellular matrix-degrading invadopodia. Morphological and gene microarray analysis following Syk knockdown revealed a loss of luminal and differentiated epithelial features with epithelial to mesenchymal transition and a gain in invadopodial cell surface markers CD44, CD49F, and MMP14. These results support the role of Syk in limiting proliferation and invasion of epithelial cells during normal morphogenesis, and emphasize the critical role of Syk as a tumor suppressor for breast cancer. The question of breast cancer risk following systemic anti-Syk therapy is raised since only partial loss of Syk was sufficient to induce mammary carcinomas.