Macrophage-expressed CD51 promotes cancer stem cell properties via the TGF-ß1/smad2/3 axis in pancreatic cancer.

Macrophage-targeted therapy offers new options for intractable pancreatic ductal adenocarcinoma (PDAC), which has a low 5-year survival rate. However, the factors regulating the biological function and phenotype of macrophages in PDAC are incompletely understood. Here, we found that CD51 was positively associated with the poor prognosis of PDAC patients and was highly expressed on macrophages but not on pancreatic cancer cells. Subsequently, we found that CD51 was a marker of macrophages, which promoted the stemness of pancreatic cancer cells. Furthermore, knockdown of CD51 in macrophages drove macrophages toward an M1-like phenotype. Mechanistically, macrophage-expressed CD51 contributed to the acquisition of stemness traits of pancreatic cancer cells by regulating the TGF-ß1/smad2/3 pathway. Our data demonstrate the central role played by macrophage-expressed CD51 in the acquisition of stemness traits of pancreatic cancer cells through the paracrine induction of TGF-ß1. We first show the connection between the CD51/TGF-ß1/smad2/3 axis and PDAC cancer stem cell properties and then indicate that CD51-targeted therapy is a new therapeutic modality for PDAC.

Inhibition of skin carcinogenesis by suppression of NF-κB dependent ITGAV and TIMP-1 expression in IL-32γ overexpressed condition.

BACKGROUND: Interleukin-32 (IL-32) has been associated with various diseases. Previous studies have shown that IL-32 inhibited the development of several tumors. However, the role of IL-32γ, an isotype of IL-32, in skin carcinogenesis remains unknown. METHODS: We compared 7,12-Dimethylbenz[a]anthracene/12-O-Tetradecanoylphorbol-13-acetate (DMBA/TPA)-induced skin carcinogenesis in wild type (WT) and IL-32γ-overexpressing mice to evaluate the role of IL-32γ. We also analyzed cancer stemness and NF-κB signaling in skin cancer cell lines with or without IL-32γ expression by western blotting, quantitative real-time PCR and immunohistochemistry analysis. RESULTS: Carcinogen-induced tumor incidence in IL-32γ mice was significantly reduced in comparison to that in WT mice. Infiltration of inflammatory cells and the expression levels of pro-inflammatory mediators were decreased in the skin tumor tissues of IL-32γ mice compared with WT mice. Using a genome-wide association study analysis, we found that IL-32 was associated with integrin αV (ITGAV) and tissue inhibitor of metalloproteinase-1 (TIMP-1), which are critical factor for skin carcinogenesis. Reduced expression of ITGAV and TIMP-1 were identified in DMBA/TPA-induced skin tissues of IL-32γ mice compared to that in WT mice. NF-κB activity was also reduced in DMBA/TPA-induced skin tissues of IL-32γ mice. IL-32γ decreased cancer cell sphere formation and expression of stem cell markers, and increased chemotherapy-induced cancer cell death. IL-32γ also downregulated expression of ITGAV and TIMP-1, accompanied with the inhibition of NF-κB activity. In addition, IL-32γ expression with NF-κB inhibitor treatment further reduced skin inflammation, epidermal hyperplasia, and cancer cell sphere formation and downregulated expression levels of ITGAV and TIMP-1. CONCLUSIONS: These findings indicated that IL-32γ suppressed skin carcinogenesis through the inhibition of both stemness and the inflammatory tumor microenvironment by the downregulation of TIMP-1 and ITGAV via inactivation of NF-κB signaling.

CD51 is an independent unfavorable prognostic factor in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common cancer in East Asia and some other parts of the world with a dismal prognosis. CD51 (integrin αv),a transmembrane glycoprotein responsible for cell-to-matrix binding has been found to enhance tumor progression. However, its expression and clinicopathological significance in ESCC tumors are not fully understood. The purpose of this study was to investigate the expression level of CD51 and to explore its clinicopathological significance in ESCC. METHODS: The expression of CD51 in 122 ESCC samples was examined by immunohistochemistry and its clinicopathological significance was evaluated. RESULTS: The expression of CD51 was observed in tumor cell membrane and/or cytoplasm, with a positive rate of 48.36% (59/122). High expression of CD51 was significantly associated with lymph node metastasis (P =  0.031), tumor size (P =  0.028) and invasive depth (P =  0.027). Kaplan-Meier analysis revealed that positive expression of CD51 was correlated with poor overall survival of ESCC patients (P =  0.015). Multivariate analysis suggested that CD51 was an independent prognositic factor for ESCC (hazard ration = 1.604; 95% CI, 1.086-2.368; P =  0.017). CONCLUSION: These data suggested CD51 was a predictor for the prognosis of ESCC patients.

p53-dependent CD51 expression contributes to characteristics of cancer stem cells in prostate cancer.

Castration-resistant prostate cancer (CRPC), which is considered to contain cancer stem cells (CSCs), leads to a high relapse rate in patients with prostate cancer (PCa). However, the markers of prostate CSCs are controversial. Here we demonstrate that CD51, in part, correlates with the poor prognosis of PCa patients. Further, we find that CD51 is a functional molecule that is able to promote the malignancy of PCa through enhancing tumor initiation, metastatic potential, and chemoresistance. Moreover, we find that elevated CD51 expression in PCa specimens correlates with p53 loss of function. Mechanistically, we demonstrate that p53 acts via Sp1/3 to repress CD51 transcription, and CD51 is required for PCa stemness and metastasis properties, and is downregulated by p53. Taken together, these results indicate that CD51 is a novel functional marker for PCa, which may provide a therapeutic target for the efficiently restricting PCa progression.

Novel probiotics isolated from a Japanese traditional fermented food, Funazushi, attenuates DSS-induced colitis by increasing the induction of high integrin αv/ß8-expressing dendritic cells.

BACKGROUND: We isolated two novel probiotics strains (s193 and s292) from Funazushi, which is a traditional Japanese fermented food, and evaluated its effects on DSS-induced colitis to determine the possible underlying mechanisms. METHODS: A single colony from homogenized Funazushi was isolated by its ability to suppress TNF-α in RAW 264.7. Effect of probiotics on colonic inflammation induced by DSS was evaluated. Effect of probiotics on Treg induction by CD11c+ dendritic cells (DCs) of MLNs were analyzed. RESULTS: Two novel probiotics strains classified into the genus Lactobacillus were isolated (s193 and s292), and those strains showed stronger anti-inflammatory effects on DSS-induced colitis than those of L. gasseri isolated from the gut. mRNA expression ß8 integrin in CD11c+DCs of MLNs and the number of Tregs in the large intestine were significantly increased by s193 and s292 administration compared with L. gasseri administration. Bone marrow DCs treated with s193 and s292 highly increased ß8 integrin, and those cells strongly induced differentiation of CD4+ T cells into Tregs. Differentiation of Tregs was remarkably inhibited by anti-ß8 integrin antibody treatment. CONCLUSIONS: Strains s193 and s292 demonstrate strong anti-inflammatory effects on DSS-induced colitis through induction of ß8 integrin expression on DCs. Our results suggested that Japanese traditional fermented foods are valuable sources for probiotics that are effective for IBD therapy and treatment.

High αv Integrin Level of Cancer Cells Is Associated with Development of Brain Metastasis in Athymic Rats.

BACKGROUND/AIM: Brain metastases commonly occur in patients with malignant skin, lung and breast cancers resulting in high morbidity and poor prognosis. Integrins containing an αv subunit are cell adhesion proteins that contribute to cancer cell migration and cancer progression. We hypothesized that high expression of αv integrin cell adhesion protein promoted metastatic phenotypes in cancer cells. MATERIALS AND METHODS: Cancer cells from different origins were used and studied regarding their metastatic ability and intetumumab, anti-αv integrin mAb, sensitivity using in vitro cell migration assay and in vivo brain metastases animal models. RESULTS: The number of brain metastases and the rate of occurrence were positively correlated with cancer cell αv integrin levels. High αv integrin-expressing cancer cells showed significantly faster cell migration rate in vitro than low αv integrin-expressing cells. Intetumumab significantly inhibited cancer cell migration in vitro regardless of αv integrin expression level. Overexpression of αv integrin in cancer cells with low αv integrin level accelerated cell migration in vitro and increased the occurrence of brain metastases in vivo. CONCLUSION: αv integrin promotes brain metastases in cancer cells and may mediate early steps in the metastatic cascade, such as adhesion to brain vasculature. Targeting αv integrin with intetumumab could provide clinical benefit in treating cancer patients who develop metastases.

miR-17 inhibits ovarian cancer cell peritoneal metastasis by targeting ITGA5 and ITGB1.

An essential step in the peritoneal spread of ovarian cancer is the adhesion and implantation of tumor cells to the mesothelium layer. Integrin α5 and ß1 have been reported to mediate the initial adhesion process and to correlate with disease survival in ovarian cancer. However, the molecular mechanism of integrin α5ß1 dysregulation in tumorigenesis and metastasis remained enigmatic. In the present study, using the US NCI60 database, we identified miR-17 as a candidate regulator targeting both integrin α5 and ß1. The level of miR-17 was evidently inversely correlated with that of α5 and ß1 in ovarian cancer cell lines. Specifically, miR-17 bound directly to the 3' untranslated region (3'UTR) of α5 and ß1 and suppressed their expression. Forced expression of miR-17 led to markedly diminished adhesion and invasion of ovarian cancer cells in vitro, and notably reduced metastatic nodules inside the peritoneal cavity in in vivo SKOV3 xenografts model. Moreover, ectopic expression of miR-17 in ovarian cancer cells resulted in repressed ILK phosphorylation as well as decreased production of active matrix metalloproteinase-2 (MMP-2). Our results indicated that miR-17 hampered ovarian cancer peritoneal propagation by targeting integrin α5 and ß1. These findings supported the utility of miR-17/α5ß1 to be considered as valuable marker for metastatic potential of ovarian cancer cells, or a therapeutic target in ovarian cancer treatment.

Nitric oxide increases the migratory activity of non-small cell lung cancer cells via AKT-mediated integrin αv and ß1 upregulation.

BACKGROUND: Previously, nitric oxide (NO) has been found to affect the metastatic behavior of various types of cancer. In addition, it has been found that alterations in integrin expression may have profound effects on cancer cell survival and migration. Here, we aimed at assessing the effects of non-toxic concentrations of NO on human non-small cell lung cancer (NSCLC) cells, including the expression of integrins and the migration of these cells. METHODS: The cytotoxic and proliferative effects of NO on human NSCLC-derived H460, H292 and H23 cells were tested by MTT assay. The migration capacities of these cells was evaluated by wound healing and transwell migration assays. The expression of integrins and migration-associated proteins was determined by Western blot analyses. RESULTS: We found that NO treatment caused a significant increase in the expression of integrin αv and ß1 in all three NSCLC-derived cell lines tested. Known migration-associated proteins acting downstream of these integrins, including focal adhesion kinase (FAK), active RhoA (Rho-GTP) and active cell division control 42 (Cdc42-GTP), were found to be significantly activated in response to NO. In addition, we found that NO-treated cells showed an increased motility and that this motility was associated with a significant increase in the number of filopodia per cell. We also found that NO-treated cells exhibited increased active protein kinase G (PKG), protein kinase B (AKT) and FAK expression levels. Using a pharmacological approach, we found that the integrin-modulating effect of NO is most likely brought about by a PKG/AKT-dependent mechanism, since the observed changes in integrin expression were abolished by AKT inhibitors, but not by FAK inhibitors. CONCLUSION: Our data suggest a novel role of NO in the regulation of integrin expression and, concomitantly, the migratory capacity of NSCLC cells.

Transforming growth factor (TGF) ß1 acted through miR-130b to increase integrin α5 to promote migration of colorectal cancer cells.

Transforming growth factor (TGF)-ß1 is a significant stimulator of tumor invasion and metastasis. More recently, it has been found that TGF-ß1 acts through microRNAs to regulate their target genes to promote cancer progresses. However, such similar regulation is rarely reported in colorectal cancer (CRC). Here, we observed a decrease in TGF-ß1 expression in CRC specimens, compared with matched adjacent normal tissues. In parallel, there was an increase in miR-130b characterized in the same samples by microarray assay. Further, treatment of CRC cells with TGF-ß1 caused a significant decrease in the expression of miR-130b and an increased CRC cell migration. Luciferase reporter assay revealed that miR-130b directly targeted the 3' untranslated region (3'UTR) region of integrin α5 gene, which encodes a key molecule involved in cell motility. Subsequently, in the overexpression of miR-130b CRC cells, we observed a decreased level of integrin α5 protein. The regulation of integrin α5 by miR-130b was further shown using the miR-130b mimics and inhibitor of miR-130b. And, knockdown miR-130b with inhibitor in the overexpression of miR-130b CRC cells recovered integrin α5 expression and integrin α5-mediated cell motility. Moreover, the inverse relevance between miR-130b and integrin α5 was also observed in CRC specimens. At last, the enhancement of integrin α5 in TGF-ß1-treated cells can be reversed partly when rescuing miR-130b expression. Together, our findings suggested that TGF-ß1 acted through miR-130b to promote integrin α5 expression, resulting in the enhanced migration of CRC cells.

Bottom-up topography assembly into 3D porous scaffold to mediate cell activities.

Native cells live in a three-dimensional (3D) extracellular matrix (ECM) capable of regulating cell activities through various physical and chemical factors. Designed topographies have been well proven to trigger significant difference in cell behaviours. However, present topographies are almost all constructed on two-dimensional (2D) substrates like discs and films, which are far from features like 3D and porosity required in application like bone repair. Here we bottom-up assembled poly(lactic-co-glycolic acid)/calcium carbonate (PLGA/CC) microspheres with superficial porous topography intactly into a 3D porous scaffold. Because the scaffold was obtained through a mild technique, the bioactivity of released BMP-2 was well retained. Mouse bone marrow mesenchymal stem cells (mMSCs) were cultured on produced scaffolds having different 3D topographies. It turned out that osteogenic differentiation of mMSCs did respond to the 3D topographies, while proliferation didn't. Gene expression of αv and ß1 integrins revealed that adhesion was supposed to be the underlying mechanism for osteogenic response. The study provides insight into enhancing function of practical scaffolds by elaborate topography design. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1056-1063, 2016.

miR-25 Modulates Invasiveness and Dissemination of Human Prostate Cancer Cells via Regulation of αv- and α6-Integrin Expression.

Altered microRNA (miRNA; miR) expression is associated with tumor formation and progression of various solid cancers. A major challenge in miRNA expression profiling of bulk tumors is represented by the heterogeneity of the subpopulations of cells that constitute the organ, as well as the tumor tissue. Here, we analyzed the expression of miRNAs in a subpopulation of epithelial stem/progenitor-like cells in human prostate cancer [prostate cancer stem cell (PCSC)] and compared their expression profile to more differentiated cancer cells. In both cell lines and clinical prostate cancer specimens, we identified that miR-25 expression in PCSCs was low/absent and steadily increased during their differentiation into cells with a luminal epithelial phenotype. Functional studies revealed that overexpression of miR-25 in prostate cancer cell lines and selected subpopulation of highly metastatic and tumorigenic cells (ALDH(high)) strongly affected the invasive cytoskeleton, causing reduced migration in vitro and metastasis via attenuation of extravasation in vivo. Here, we show, for the first time, that miR-25 can act as a tumor suppressor in highly metastatic PCSCs by direct functional interaction with the 3'-untranslated regions of proinvasive αv- and α6-integrins. Taken together, our observations suggest that miR-25 is a key regulator of invasiveness in human prostate cancer through its direct interactions with αv- and α6-integrin expression.

Abituzumab combined with cetuximab plus irinotecan versus cetuximab plus irinotecan alone for patients with KRAS wild-type metastatic colorectal cancer: the randomised phase I/II POSEIDON trial.

BACKGROUND: Integrins are involved in tumour progression and metastasis, and differentially expressed on colorectal cancer (CRC) cells. Abituzumab (EMD 525797), a humanised monoclonal antibody targeting integrin αν heterodimers, has demonstrated preclinical activity. This trial was designed to assess the tolerability of different doses of abituzumab in combination with cetuximab and irinotecan (phase I) and explore the efficacy and tolerability of the combination versus that of cetuximab and irinotecan in patients with metastatic CRC (mCRC) (phase II part). METHODS: Eligible patients had KRAS (exon 2) wild-type mCRC and had received prior oxaliplatin-containing therapy. The trial comprised an initial safety run-in using abituzumab doses up to 1000 mg combined with a standard of care (SoC: cetuximab plus irinotecan) and a phase II part in which patients were randomised 1 : 1 : 1 to receive abituzumab 500 mg (arm A) or 1000 mg (arm B) every 2 weeks combined with SoC, or SoC alone (arm C). The primary end point was investigator-assessed progression-free survival (PFS). Secondary end points included overall survival (OS), response rate (RR) and tolerability. Associations between tumour integrin expression and outcomes were also assessed. RESULTS: Phase I showed that abituzumab doses up to 1000 mg were well tolerated in combination with SoC. Seventy-three (arm A), 71 (arm B) and 72 (arm C) patients were randomised to the phase II part. Baseline characteristics were balanced. PFS was similar in the three arms: arm A versus SoC, hazard ratio (HR) 1.13 [95% confidence interval (CI) 0.78-1.64]; arm B versus SoC, HR 1.11 (95% CI 0.77-1.61). RRs were also similar. A trend toward improved OS was observed: arm A versus SoC, HR 0.83 (95% CI 0.54-1.28); arm B versus SoC, HR 0.80 (95% CI 0.52-1.25). Grade ≥3 treatment-emergent adverse events were observed in 72%, 78% and 67% of patients. High tumour integrin αvß6 expression was associated with longer OS in arms A [HR 0.55 (0.30-1.00)] and B [HR 0.41 (0.21-0.81)] than in arm C. CONCLUSION: The primary PFS end point was not met, although predefined exploratory biomarker analyses identified subgroups of patients in whom abituzumab may have benefit. The tolerability of abituzumab combined with cetuximab and irinotecan was acceptable. Further study is warranted. CLINICALTRIALS.GOV IDENTIFIER: NCT01008475.

Overexpression of integrin αv facilitates proliferation and invasion of oral squamous cell carcinoma cells via MEK/ERK signaling pathway that is activated by interaction of integrin αvß8 with type â collagen.

To examine the role of integrin αv subunit in the progression of squamous cell carcinoma (SCC), oral SCC cells were stably transfected with integrin αv cDNA. Integrin αv transfectants exhibited the enhancement of proliferation on type Ⅰ collagen, and seemed to have a high ability to invade type Ⅰ collagen gel. Overexpression of integrin αv led to rapid phosphorylation of focal adhesion kinase (FAK), mitogen­activated protein kinase kinase 1/2 (MEK1/2) and extracellular signal­regulated kinase 1/2 (ERK1/2) in SCC cells on type Ⅰ collagen. The downregulation of integrin ß8 in integrin αv transfectants by its specific antisense oligonucleotide led to a decrease in type Ⅰ collagen­stimulated activation of FAK and the MEK/ERK signaling pathway, and also suppressed the proliferation on type Ⅰ collagen and the invasiveness into type Ⅰ collagen gel. Moreover, the expression of integrin ß8 was induced following transfection with integrin αv cDNA. These results indicated that the overexpression of integrin αv induces integrin αvß8 heterodimer formation and the binding of integrin αvß8 to type Ⅰ collagen might enhance the proliferation and invasion of SCC cells via the activation of the MEK/ERK signaling pathway.

Role of lipid raft components and actin cytoskeleton in fibronectin-binding, surface expression, and de novo synthesis of integrin subunits in PGE2- or 8-Br-cAMP-stimulated mastocytoma P-815 cells.

Integrins are heterodimeric adhesion receptors essential for adhesion of non-adherent cells to extracellular ligands such as extracellular matrix components. The affinity of integrins for ligands is regulated through a process termed integrin activation and de novo synthesis. Integrin activation is regulated by lipid raft components and the actin structure. However, there is little information on the relationship between integrin activation and its de novo synthesis. Cancerous mouse mast cells, mastocytoma P-815 cells (P-815 cells) are known to bind to fibronectin through de novo synthesis of integrin subtypes by prostaglandin (PG) E2 stimulation. The purpose of this study was to clarify the relationship between lipid raft components and the actin cytoskeleton, and PGE2-induced P-815 cells adhesion to fibronectin and the increase in surface expression and mRNA and protein levels of αvß3 and αIIbß3 integrins. Cholesterol inhibitor 6-O-α-maltosyl-ß cyclodextrin, glycosylphosphatidylinositol-anchored proteins inhibitor phosphatidylinositol-specific phospholipase C and actin inhibitor cytochalasin D inhibited PGE2-induced cell adhesion to fibronectin, but did not regulate the surface expression and mRNA and protein levels of αv and αIIb, and ß3 integrin subunits. In addition, inhibitor of integrin modulate protein CD47 had no effect on PGE2- and 8-Br-cAMP-induced cell adhesion. These results suggest that lipid raft components and the actin cytoskeleton are directly involved in increasing of adhesion activity of integrin αIIb, αv and ß3 subunits to fibronectin but not in stimulating of de novo synthesis of them in PGE2-stimulated P-815 cells. The modulation of lipid rafts and the actin structure is essential for P-815 cells adhesion to fibronectin.

The endothelin-integrin axis is involved in macrophage-induced breast cancer cell chemotactic interactions with endothelial cells.

Elevated macrophage infiltration in tumor tissues is associated with breast cancer metastasis. Cancer cell migration/invasion toward angiogenic microvasculature is a key step in metastatic spread. We therefore studied how macrophages stimulated breast cancer cell interactions with endothelial cells. Macrophages produced cytokines, such as interleukin-8 and tumor necrosis factor-α, to stimulate endothelin (ET) and ET receptor (ETR) expression in breast cancer cells and human umbilical vascular endothelial cells (HUVECs). ET-1 was induced to a greater extent from HUVECs than from breast cancer cells, resulting in a density difference that facilitated cancer cell chemotaxis toward HUVECs. Macrophages also stimulated breast cancer cell adhesion to HUVECs and transendothelial migration, which were repressed by ET-1 antibody or ETR inhibitors. The ET axis induced integrins, such as αV and ß1, and their counterligands, such as intercellular adhesion molecule-2 and P-selectin, in breast cancer cells and HUVECs, and antibodies against these integrins efficiently suppressed macrophage-stimulated breast cancer cell interactions with HUVECs. ET-1 induced Ets-like kinase-1 (Elk-1), signal transducer and activator of transcription-3 (STAT-3), and nuclear factor-κB (NF-κB) phosphorylation in breast cancer cells. The use of inhibitors to prevent their phosphorylation or ectopic overexpression of dominant-negative IκBα perturbed ET-1-induced integrin αV and integrin ß1 expression. The physical associations of these three transcriptional factors with the gene promoters of the two integrins were furthermore evidenced by a chromatin immunoprecipitation assay. Finally, our mouse orthotopic tumor model revealed an ET axis-mediated lung metastasis of macrophage-stimulated breast cancer cells, suggesting that the ET axis was involved in macrophage-enhanced breast cancer cell endothelial interactions.

Cilengitide, a small molecule antagonist, targeted to integrin αν inhibits proliferation and induces apoptosis of laryngeal cancer cells in vitro.

Cilengitide is a chemical synthesis cyclopeptide containing RGD sequence, which can be used as a small molecule antagonist targeted to integrin αν (ITGAV). The aim of present study was to investigate the effect on proliferation and cell apoptosis of the cilengitide in laryngeal cancer cells. In the study, we have treatmented the cultured cells of laryngeal cancer (Hep-2) with cilengitide. After the medication, the proliferation of the Hep-2 cells was detected by MTT assay, the expression of ITGAV was detected by RT-PCR and the activity of caspase-3 protein was detected by a specialized kit. RGD linear peptides (GRGDSP), non-RGD linear peptide (GRGESP), and 5-fluorouracil (5-Fu) were used as controls. Results showed that the proliferation of Hep-2 cells was signally inhibited by the cilengitide with a time and dose compliance. Its inhibition effect was significantly higher than that of 5-Fu and GRGDSP, but the GRGESP showed no obvious inhibitory effect. After intervene of cilengitide, the activity of caspase-3 protein of Hep-2 cells was significantly increased, and the expression of ITGAV was significantly decreased. 5-Fu significantly inhibited the proliferation of Hep-2 cells, but no significant changes of ITGAV expression were observed. In conclusion, cilengitide can significantly down-regulate ITGAV expression and inhibit cell proliferation in laryngeal cancer cells, it will also to induce cell apoptosis through caspase-3 pathway. Therefore, it could be as a kind of effective chemotherapy drugs that will be used in clinical treatment of the laryngeal cancer.

Ovarian stimulation by exogenous gonadotropin decreases the implantation rate and expression of mouse blastocysts integrins.

BACKGROUND: Integrins are heterodimeric glycoprotein receptors that regulate the interaction of cells with extracellular matrix and may have a critical role in implantation. The aim of this study was to investigate the effect of ovulation induction on the expression of α4, αv, ß1, and ß3 integrins in mouse blastocyst at the time of implantation. METHODS: The ovarian stimulated and non-stimulated pregnant mice were sacrificed on the morning of 5th day of pregnancy. The blastocysts were collected, and the expression of αv, α4, ß1, and ß3 integrins was examined using real-time RT-PCR and immunocytochemical techniques, then their ovarian hormones were analyzed at the same time. The implantation sites in uterine horns of other pregnant mice in both groups were determined under a stereomicroscope on the 7th day of pregnancy. RESULTS: The results showed that the expression of αv, ß1, and ß3 integrins in both mRNA and protein levels was significantly lower in the ovarian stimulated group than the control group, and the maximum ratio of expression was belonged to ß1 molecule (P>0.05). CONCLUSION: The implantation rate in superovulated mice was significantly lower than control mice. It was suggested that ovulation induction decreased the expression of αv, ß1, and ß3 integrins of mouse blastocysts.

αv-Integrin isoform expression in primary human tumors and brain metastases.

UNLABELLED: To determine whether metastasis to brain is associated with altered expression patterns of integrins, we investigated the expression of αvß3, αvß5, αvß6 and αvß8 integrins in primary malignancies and metastases to brain of breast, lung and renal carcinomas and in malignant melanoma. Inhibitors of αv integrins are currently in clinical trials for glioblastoma. The role of integrins in the process of brain metastasis from other human tumors is unknown. Immunohistochemistry with novel integrin subtype specific rabbit monoclonal antibodies was performed on tissue microarrays of archival material of surgical biopsies taken from primary tumors and brain metastases. Integrin αvß3 expression was increased in brain metastases compared to primary tumors of breast adenocarcinoma, non-small cell lung cancer, renal clear cell cancer and malignant cutaneous melanoma (all p < 0.01). Similarly, integrin αvß8 expression was increased in brain metastases compared to primary tumors of breast cancer (p < 0.0001), lung cancer (p < 0.01) and renal cancer (p < 0.0001), with a similar trend in metastatic melanoma. Integrin αvß5 was expressed in most primary tumors (98% breast cancer; 67% lung cancer; 90% renal cancer; 89% melanoma) and showed a stronger expression in brain metastases compared to primary tumors from lung cancer and melanoma (p < 0.05). Also integrin αvß6 expression was increased in brain metastases compared to primary breast cancer (p < 0.001). CONCLUSIONS: The stronger αv-integrin expression in brain metastases, especially of αvß3 and αvß8 integrins, suggests that certain αv integrin are involved in the process of brain metastasis. αv Integrins may be therapeutic targets for patients with metastatic cancer in brain.

Longitudinal expression analysis of αv integrins in human gliomas reveals upregulation of integrin αvß3 as a negative prognostic factor.

Integrin inhibitors targeting αv series integrins are being tested for their therapeutic potential in patients with brain tumors, but pathologic studies have been limited by lack of antibodies suitable for immunohistochemistry (IHC) on formalin-fixed, paraffin-embedded specimens. We compared the expression of αv integrins by IHC in brain tumor and normal human brain samples with gene expression data in a public database using new rabbit monoclonal antibodies against αvß3, αvß5, αvß6, and αvß8 complexes using both manual and automated microscopy analyses. Glial tumors usually shared an αvß3-positive/αvß5-positive/αvß8-positive/αvß6-negative phenotype. In 94 WHO (World Health Organization) grade II astrocytomas, 85 anaplastic astrocytomas WHO grade III, and 324 glioblastomas from archival sources, expression of integrins generally increased with grade of malignancy. Integrins αvß3 and αvß5 were expressed in many glioma vessels; the intensity of vascular expression of αvß3 increased with grade of malignancy, whereas αvß8 was absent. Analysis of gene expression in an independent cohort showed a similar increase in integrin expression with tumor grade, particularly of ITGB3 and ITGB8; ITGB6 was not expressed, consistent with the IHC data. Parenchymal αvß3 expression and ITGB3 gene overexpression in glioblastomas were associated with a poor prognosis, as revealed by survival analysis (Kaplan-Meier logrank, p = 0.016). Together, these data strengthen the rationale for anti-integrin treatment of glial tumors.

Hepatic sinusoidal endothelium avidly binds platelets in an integrin-dependent manner, leading to platelet and endothelial activation and leukocyte recruitment.

Platelets have recently been shown to drive liver injury in murine models of viral hepatitis and promote liver regeneration through the release of serotonin. Despite their emerging role in inflammatory liver disease, little is known about the mechanisms by which platelets bind to the hepatic vasculature. Therefore, we referenced public expression data to determine the profile of potential adhesive receptors expressed by hepatic endothelium. We then used a combination of tissue-binding and flow-based endothelial-binding adhesion assays to show that resting platelets bind to human hepatic sinusoidal endothelial cells and that the magnitude of adhesion is greatly enhanced by thrombin-induced platelet activation. Adhesion was mediated by the integrins Gp1b, αIIbßIII, and αvß3, as well as immobilized fibrinogen. Platelet binding to hepatic endothelial cells resulted in NF-κB activation and increased chemokine secretion. The functional relevance of platelet binding was confirmed by experiments that showed markedly increased binding of neutrophils and lymphocytes to hepatic endothelial cells under shear conditions replicating those found in the hepatic sinusoid, which was in part dependent on P-selectin expression. Thus the ability of platelets to activate endothelium and promote leukocyte adhesion may reflect an additional mechanism through which they promote liver injury.