Integrin Αvβ3 Expression Research Articles

RGDSK Peptide Functionalized Helical Rosette Nanotubes (RGDSK‐HRNs) Inhibit E. coli Adherence to Jejunal Epithelium by Blocking Integrin αvβ3

There is an ongoing effort to find ways to reduce the intestinal colonization of pathogens in both animals and humans. Integrin αvβ3, recognizing arginine‐glycine‐aspartic acid (RGD) sequences, has important functions in cell adhesion, signaling, and survival. However, the role of this protein in the adhesion of bacteria, particularly E. coli to the jejunum, remain elusive. Therefore, to explore the expression of integrin αvβ3 and its role in interaction with a novel treatment ‐ RGDSK‐HRNs in E. coli binding, we performed a series of experiments using porcine jejunum, intestinal porcine epithelial 1 cell line (IPEC1) and E. coli K88.Immunohistochemistry staining results showed that the normal porcine jejunum strongly expressed integrin αvβ3 on the nucleus and apical surface of epithelium and gland cells. The expression of integrin αvβ3 decreased in the epithelium of the jejunum infected with E. coli or E. coli associated with Salmonella. Using immune‐gold staining with the integrin αvβ3 antibody, we recognized that integrin αvβ3 was expressed on the plasma membrane, cytoplasm, and nucleus of IPEC1. In the porcine jejunum, integrin αvβ3 was also found in epithelial microvilli. Immuno‐precipitation and western blot data showed that the expression of integrin αvβ3 on IPEC1 decreased at 15 minutes but returned to normal after 90 minutes of infection with E. coli K88 (P<0.05). We also found that the E. coli K88 had a protein‐like integrin αvβ3.In this study, we reported that dose‐dependent RGDSK‐HRNs mediated the attachment of E. coli to IPEC1 (P<0.001). Interestingly, RGDSK‐HRNs slightly induced IPEC1 apoptosis compared to the normal untreated group but significantly enhanced the survival of IPEC1 upon E. coli infection compared to the E. coli infection group (P<0.05). Data from binding assays on 96‐well plates showed that the number of E. coli binding on the integrin αvβ3 coated wells was significantly higher than that binding on uncoated ones with the same dose of E. coli (P<0.05). We then performed ex‐vivo villus adhesion assays on scraped villi from porcine jejunum. Data showed that in F4 receptor positive villi, RGDSK‐HRNs significantly reduced the number of adhering E. coli up to 12 hours compared with the E. coli‐only challenging group (P<0.05). Both RGDSK peptide and monoclonal antibody anti integrin αvβ3 control groups remained effective in inhibiting the E. coli binding to villi up to 24 hours. Confocal images confirmed the binding of RGDSK‐HRNs‐FITC to both villi and E. coli.These are the first data to show the role for the integrin αvβ3 in the adherence of E. coli to the intestinal epithelium, and that novel RGDSK‐HRNs, a potential alternative to antibiotics, can inhibit the attachment of E. coli to the intestinal epithelium.Support or Funding InformationWe thank the Saskatchewan Agriculture Development Fund (ADF); the Natural Science and Engineering Research Council (NSERC); Graduate Student Scholarship from Integrated Training Program in Infectious Disease, Food Safety and Public Policy (ITraP); Devolved Graduate Scholarship from Department of Veterinary Biomedical Sciences; and Graduate Student Scholarship from Western College of Veterinary Medicine, University of Saskatchewan, Canada for supporting this research. We thank Professor Douglas Call at Washington State University, USA. for pFPV::td tomato plasmid gift; Ms. LaRhonda Sobchishin, Ms. Eiko Kawamura, and Dr. Abdul Lone at the University of Saskatchewan for technical support.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Integrin expression and glycosylation patterns regulate cell-matrix adhesion and alter with breast cancer progression

Integrins are the major cell adhesion glycoproteins involved in cell-extracellular matrix (ECM) interaction and metastasis. Further, glycosylation on integrin is necessary for its proper folding and functionality. Herein, differential expression of integrins viz., αvβ3 and αvβ6 was examined in MDA-MB-231, MDA-MB-468 and MCF-10A cells, which signify three different stages of breast cancer development from highly metastatic to non-tumorigenic stage. The expression of αvβ3 and αvβ6 integrins at mRNA and protein levels was observed in all three cell lines and the results displayed a distinct pattern of expression. Highly metastatic cells showed enhanced expression of αvβ3 than moderate metastatic and non-tumorigenic cells. The scenario was reversed in case of αvβ6 integrin, which was strongly expressed in moderate metastatic and non-tumorigenic cells. N-glycosylation of αvβ3 and αvβ6 integrins is required for the attachment of cells to ECM proteins like fibronectin. The cell adhesion properties were found to be different in these cancer cells with respect to the type of integrins expressed. The results testify that αvβ3 integrin in highly metastatic cells, αvβ6 integrin in both moderate metastatic and non-tumorigenic cells play an important role in cell adhesion. The investigation typify that N-glycosylation on integrins is also necessary for cell-ECM interaction. Further, glycosylation inhibition by Swainsonine is found to be more detrimental to invasive property of moderate metastatic cells. Conclusively, types of integrins expressed as well as their N-glycosylation pattern alter during the course of breast cancer progression.

Integrin αvβ6 Promotes Lung Cancer Proliferation and Metastasis through Upregulation of IL-8–Mediated MAPK/ERK Signaling

Lung cancer is notorious for high morbidity and mortality around the world. Interleukin (IL)-8, a proinflammatory chemokine with tumorigenic and proangiogenic effects, promotes lung cancer cells growth and migration and contributes to cell aggressive phenotypes. Integrin αvβ6 is a receptor of transmembrane heterodimeric cell surface adhesion, and its overexpression correlates with poor survival from non–small cell lung cancer. However, the cross talk between αvβ6 and IL-8 in lung cancer has not been characterized so far. Herein, human lung cancer samples were analyzed, and it revealed that the immunohistochemical and mRNA expression of integrin αvβ6 was significantly correlated with the expression of IL-8. Furthermore, in vitro, integrin αvβ6 increased cell proliferation, migration, and invasion by impairing the expressions of MMP-2 and MMP-9 and inhibited cell apoptosis in human lung cancer cells A549 and H460. In addition, integrin αvβ6 upregulated IL-8 expression through activating MAPK/ERK signaling. The in vivo experiment showed that integrin αvβ6 promoted tumor growth in xenograft model mice by accelerating tumor volume and reducing apoptosis. Meanwhile, lung metastasis model experiment suggested that integrin αvβ6 stimulated tumor metastasis with the increase of lung/total weight and tumor nodules. Simultaneously, integrin αvβ6 upregulated IL-8 expression detected by both Western blots and immunohistochemistry, along with the activation of MAPK/ERK signaling. Overall, these data suggested that, in vitro and in vivo, integrin αvβ6 promoted lung cancer proliferation and metastasis, at least in part, through upregulation of IL-8–mediated MAPK/ERK signaling. Thus, the inhibition of integrin αvβ6 and IL-8 may be the key for the treatment of lung cancer.

High expression of integrin αvβ3 enables uptake of targeted fluorescent probes into ovarian cancer cells and tumors

The cell line OVCAR-4 was recently ranked as one of the most representative cell lines for high grade serous ovarian cancer (HGSOC). However, little work has been done to assess the susceptibility of OVCAR-4 cells and tumors to the more common types of molecular targeting. Proteome profiles suggest OVCAR-4 express high levels of integrin αvβ3 receptors. Using flow cytometry with fluorescent antibodies we determined that OVCAR-4 cells have high number of integrin αvβ3 receptors ([9.8 ± 2.5] × 104/cell) compared to the well-characterized cell line U87-MG ([5.2 ± 1.4] × 104/cell). However, OVCAR-4 cells also have roughly three times the surface area of U87-MG cells, so the average αvβ3 receptor density is actually lower (11 ± 3 versus 18 ± 6 receptors/µm2). A series of new fluorescent molecular probes was prepared with structures comprised of a deep-red squaraine fluorophore (∼680 nm emission) covalently attached to zero, one, or two cyclic pentapeptide cRGD sequences for integrin targeting. Microscopy studies showed that uptake of the divalent probe into cultured OVCAR-4 cells was 2.2 ± 0.4 higher than the monovalent probe, which in turn was 2.2 ± 0.4 higher than the untargeted probe. This probe targeting trend was also seen in OVCAR-4 mouse tumor models. The results suggest that clinically relevant OVCAR-4 cells can be targeted using molecular probes based on αvβ3 integrin receptor antagonists such as the cRGD peptide. Furthermore, deep-red fluorescent cRGD-squaraine probes have potential as targeted stains of cancerous tissue associated with HGSOC in surgery and pathology settings.

Vitamin D Promotes MSC Osteogenic Differentiation Stimulating Cell Adhesion and αVβ3 Expression.

Vitamin D (Vit D) by means of its biological active form, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), has a protective effect on the skeleton by acting on calcium homeostasis and bone formation. Furthermore, Vit D has a direct effect on mesenchymal stem cells (MSCs) in stimulating their osteogenic differentiation. In this work, we present for the first time the effect of 1,25(OH)2D3 on MSC adhesion. Considering that cell adhesion to the substrate is fundamental for cell commitment and differentiation, we focused on the expression of αVβ3 integrin, which has a key role in the commitment of MSCs to the osteoblastic lineage. Our data indicate that Vit D increases αVβ3 integrin expression inducing the formation of focal adhesions (FAs). Moreover, we assayed MSC commitment in the presence of the extracellular matrix (ECM) glycoprotein fibronectin (FN), which is able to favor cell adhesion on surfaces and also to induce osteopontin (OPN) expression: this suggests that Vit D and FN synergize in supporting cell adhesion. Taken together, our findings provide evidence that Vit D can promote osteogenic differentiation of MSCs through the modulation of αVβ3 integrin expression and its subcellular organization, thus favoring binding with the matrix protein (FN).

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting.

RGD-α-amanitin and isoDGR-α-amanitin conjugates were synthesized by joining integrin ligands to α-amanitin via various linkers and spacers. The conjugates were evaluated for their ability to inhibit biotinylated vitronectin binding to the purified αVβ3 receptor, retaining good binding affinity, in the same nanomolar range as the free ligands. The antiproliferative activity of the conjugates was evaluated in three cell lines possessing different levels of αVβ3 integrin expression: human glioblastoma U87 (αVβ3+), human lung carcinoma A549 (αVβ3−) and breast adenocarcinoma MDA-MB-468 (αVβ3−). In the U87, in the MDA-MB-468, and partly in the A549 cancer cell lines, the cyclo[DKP-isoDGR]-α-amanitin conjugates bearing the lysosomally cleavable Val-Ala linker were found to be slightly more potent than α-amanitin. Apparently, for all these α-amanitin conjugates there is no correlation between the cytotoxicity and the expression of αVβ3 integrin. To determine whether the increased cytotoxicity of the cyclo[DKP-isoDGR]-α-amanitin conjugates is governed by an integrin-mediated binding and internalization process, competition experiments were carried out in which the conjugates were tested with U87 (αVβ3+, αVβ5+, αVβ6−, α5β1+) and MDA-MB-468 (αVβ3−, αVβ5+, αVβ6+, α5β1−) cells in the presence of excess cilengitide, with the aim of blocking integrins on the cell surface. Using the MDA-MB-468 cell line, a fivefold increase of the IC50 was observed for the conjugates in the presence of excess cilengitide, which is known to strongly bind not only αVβ3, but also αVβ5, αVβ6, and α5β1. These data indicate that in this case the cyclo[DKP-isoDGR]-α-amanitin conjugates are possibly internalized by a process mediated by integrins different from αVβ3 (e.g., αVβ5).

14, 15-EET induces breast cancer cell EMT and cisplatin resistance by up-regulating integrin \u03b1v\u03b23 and activating FAK/PI3K/AKT signaling

Background14,15-epoxyeicosatrienoic acid (14,15-EET) is an important lipid signaling molecule involved in the regulation of tumor metastasis, however, the role and molecular mechanisms of 14,15-EET activity in breast cancer cell epithelial-mesenchymal transition (EMT) and drug resistance remain enigmatic.MethodsThe 14, 15-EET level in serum and in tumor or non-cancerous tissue from breast cancer patients was measured by ELISA. qRT-PCR and western blot analyses were used to examine expression of integrin αvβ3. The role of 14, 15-EET in breast cancer cell adhesion, invasion was explored by adhesion and Transwell assays. The role of 14, 15-EET in breast cancer cell cisplatin resistance in vitro was determined by MTT assay. Western blot was conducted to detect the protein expressions of EMT-related markers and FAK/PI3K/AKT signaling. Xenograft models in nude mice were established to explore the roles of 14, 15-EET in breast cancer cells EMT and cisplatin resistance in vivo.ResultsIn the present study, we show that serum level of 14, 15-EET increases in breast cancer patients and 14, 15-EET level of tumor tissue is higher than that of non-cancerous tissue. Moreover, 14, 15-EET increases integrin αvβ3 expression, leading to FAK activation. 14, 15-EET induces breast cancer cell EMT via integrin αvβ3 and FAK/PI3K/AKT cascade activation in vitro. Furthermore, we find that 14, 15-EET induces breast cancer cells EMT and cisplatin resistance in vivo, αvβ3 integrin and the resulting FAK/PI3K/AKT signaling pathway are responsible for 14, 15-EET induced-breast cancer cells cisplatin resistance.ConclusionsOur findings suggest that inhibition of 14, 15-EET or inactivation of integrin αvβ3/FAK/PI3K/AKT pathway could serve as a novel approach to reverse EMT and cisplatin resistance in breast cancer cells.

Antitumor effect of triptolide in T-cell lymphoblastic lymphoma by inhibiting cell viability, invasion, and epithelial-mesenchymal transition via regulating the PI3K/AKT/mTOR pathway.

IntroductionT-cell lymphoblastic lymphoma (T-LBL) is a widely disseminated disease worldwide. Triptolide (TPL) is purified from Chinese herb and displays anti-inflammatory, anti-fertility, anti-tumor and immunosuppressive effects.Materials and methodsHere, in vitro and in vivo experiments were conducted to investigate the anti-tumor effect of TPL treatment in T-LBL and the potential mechanism in T-LBL progression.ResultsTPL inhibited cell proliferation of T-LBL cells (Jurkat cells and Molt-3 cells) in a dose-dependent manner. Flow cytometry analysis showed that cell apoptosis rate was increased by TPL treatment. TPL also up-regulated the expression of Caspase-3, Bax and down-regulated the expression of Bcl-2, indicating that TPL promoted apoptosis in Jurkat cells. Moreover, TPL inhibited invasion ability of Jurkat cells and down-regulated the expression of MMP-3 and MMP-9 in a dose-dependent manner. The expression of Snail, Slug, Twist and Integrin αVβ6 was decreased and the expression of E-cadherin was increased by TPL treatment, indicating that TPL inhibited EMT of Jurkat cells. Apart from that, TPL treatment attenuated the phoslevels of PI3K, Akt and mTOR and suppressed AKT activation compared with control group, suggesting that TPL inhibited PI3K/Akt/mTOR signal pathway in T-LBL. In vivo experiments showed that TPL inhibited tumor growth of T-LBL and promoted apoptosis of tumor cells. The expression of PCNA, Bcl-2, Snail, p-PI3K, p-Akt and mTOR was suppressed by TPL in a dose-dependent manner, suggesting that TPL suppressed tumor growth and promoted apoptosis of tumor cells by inhibiting PI3K/Akt/mTOR signal pathway in T-LBL.ConclusionIn conclusion, TPL exerted anti-tumor effect in T-LBL by inhibiting cell viability, invasion and EMT via regulating the PI3K/AKT/mTOR pathway.

Integrin αVβ3-targeted SPECT/CT for the assessment of Bevacizumab therapy in orthotopic lung cancer xenografts.

The present study aimed to determine the utility of 99mTc-3PRGD2 single photon emission computed tomography (SPECT)/computed tomography (CT) for the non-invasive monitoring of the response of integrin αvβ3 expression to anti-angiogenic treatment with bevacizumab. Bevacizumab or vehicle therapy was performed in athymic nu/nu mice bearing A549 lung tumors (moderately high integrin αvβ3 expression) or PC-3 prostate tumors (low integrin αvβ3 expression) at a dose of 1 mg twice a week. The average tumor volume was 180±90 mm3 the day prior to baseline SPECT/CT. Longitudinal 99mTc-3PRGD2 SPECT/CT imaging was performed at baseline (−1 day) and at days 5 and 15. Tumors were harvested at all imaging time points for histopathological analysis with hematoxylin and eosin (H&E) and immunohistochemistry staining. Results revealed a significant difference in tumor volume between vehicle- and bevacizumab-treated groups at 5 and 15 days following the start of treatment in the A549 lung model (P<0.05). At 5 days after the start of therapy, the percent injected dose per gram of tissue (%ID/g) and tumor-to-muscle ratio for bevacizumab-treated A549 declined persistently (P<0.05). However, for the vehicle-treated A549 model, the %ID and %ID/g value increased 5 days after the start of treatment (P<0.05). For the PC-3 model, slow-growing tumors and low tumor uptake was observed throughout the study. Alterations in tumor vasculature were confirmed by histopathological H&E analysis and immunohistochemistry. In conclusion, longitudinal imaging using 99mTc-3PRGD2 SPECT/CT may be a useful tool for monitoring the anti-angiogenic effect of bevacizumab therapy.

68Ga-BBN-RGD PET/CT for GRPR and Integrin αvβ3 Imaging in Patients with Breast Cancer.

Purpose: This study was to assess a gastrin-releasing peptide receptor (GRPR) and integrin αvβ3 dual targeting tracer 68Ga-BBN-RGD for positron emission tomography (PET)/computed tomography (CT) imaging of breast cancer and metastasis. Materials and Methods: Twenty-two female patients were recruited either with suspected breast cancer on screening mammography (n = 16) or underwent breast cancer radical mastectomy (n = 6). All the 22 patients underwent PET/CT at 30-45 min after intravenous injection of 68Ga-BBN-RGD. Eleven out of 22 patients also accepted 68Ga-BBN PET/CT within 2 weeks for comparison. A final diagnosis was made based on the histopathologic examination of surgical excision or biopsy. Results: Both the primary cancer and metastases showed positive 68Ga-BBN-RGD accumulation. The T/B ratios of 68Ga-BBN-RGD accumulation were 2.10 to 9.44 in primary cancer and 1.10 to 3.71 in axillary lymph node metastasis, 3.80 to 10.7 in distant lymph nodes, 2.70 to 5.35 in lung metastasis and 3.17 to 22.8 in bone metastasis, respectively. For primary lesions, the SUVmax from 68Ga-BBN-RGD PET in ER positive group was higher than that in ER negative group (P < 0.01). For both primary and metastatic lesions, SUVmean quantified from 68Ga-BBN-RGD PET correlated well with both GRPR expression and integrin αvβ3 expression. Conclusion: This study demonstrated significant uptake of a new type of dual integrin αvβ3 and GRPR targeting radiotracer in both the primary lesion and the metastases of breast cancer. 68Ga-BBN-RGD PET/CT may be of great value in discerning both primary breast cancers, axillary lymph node metastasis and distant metastases.

The diagnosis of hepatic fibrosis by magnetic resonance and near-infrared imaging using dual-modality nanoparticles.

Hepatic fibrosis (HF), as the only reversible process of chronic liver disease, remains a big diagnostic challenge. Development of noninvasive and effective methods to assess quantitatively early-stage HF is of great clinical importance. Compared with conventional diagnostic methods, near-infrared fluorescence imaging (NIR) and magnetic resonance imaging (MRI) could offer highly sensitive and spatial resolution signals for HF detection. However, precise detection using contrast agents is not possible. Superparamagnetic iron oxide (SPIO) nanoparticles have low toxicity, high sensitivity and excellent biocompatibility. Integration of Fe3O4 nanoparticles and indocyanine green (ICG), coupled with targeting ligand of integrin αvβ3, arginine–glycine–aspartic acid (RGD) expressed on hepatic stellate cells (HSCs), were used to detect HF. Both in vivo and in vitro results showed that the SPIO@SiO2–ICG–RGD had high stability and low cytotoxicity. The biodistribution of SPIO@SiO2–ICG–RGD was significantly different between mice with HF and healthy controls. SPIO@SiO2–ICG–RGD was characterized and the results of imaging in vitro and in vivo demonstrated the expression of integrin αvβ3 on activated HSCs. These data suggest that our SPIO@SiO2–ICG–RGD probe could be used for the diagnosis of early-stage HF. This new nanoprobe with a dual-modality imaging approach holds great potential for the diagnosis and classification of HF.

Motor neuron heterogeneity and selective vulnerability in ALS

Different and selective vulnerability among motor neuron subtypes are a fundamental, but unexplained, feature of amyotrophic lateral sclerosis (ALS): fast-fatigable (FF) motor neurons are the most vulnerable, and fast fatigue-resistant/slow (FR/S) motor neurons are relatively resistant. We identified that osteopontin (OPN) can serve as a marker of FR/S motor neurons, whereas matrix metalloproteinase-9 (MMP9) is expressed by FF motor neurons in mice. In SOD1G93A ALS model mice, as the disease progressed, OPN was secreted and accumulated as granular deposits in the extracellular matrix. We also detected OPN/MMP9 co-expressed motor neurons around the disease onset. These double positive motor neurons showed the expression of αvβ3 integrin (OPN receptor) and up-regulation of ER stress markers. We discovered that the double positive motor neurons are remodeled FR/S motor neurons, which compensated for FF motor neuron degeneration (the first wave of degeneration). Genetic ablation of OPN delayed the onset of disease, but later accelerated disease progression. This reflects two modes of OPN involvement in the pathogenesis of ALS: cell-autonomous and non-cell-autonomous effects on motor neuron vulnerability. Our study suggests that OPN expressed in FR/S motor neurons is involved in the second wave of motor neuron degeneration in ALS, and an OPN-αvβ3 integrin-MMP9 axis could be a potentially useful therapeutic target for ALS.

Expression of integrin αvβ3, CXC chemokine receptor 4 and CXC chemokine receptor 7 and their relationship with lymph node metastasis in squamous cell carcinoma of head and neck

Objective: To investigate the expression of integrin αvβ3, CXC chemokine receptor (CXCR)4 and CXCR7 and their relationship with lymph node metastasis in squamous cell carcinoma of head and neck (SCCHN). Methods: The expression of integrin αvβ3, CXCR4 and CXCR7 was detected by immunohistochemistry SABC in 92 cases of primary SCCHN, metastatic lymph node, normal oral mucosa tissues and normal lymph nodes. Results: The positive rate of the expression of integrin αvβ3, CXCR4 and CXCR7 was 75% (69/92), 81%(75/92) and 76%(70/92), respectively in primary SCCHN, and was 82%(75/92), 76%(70/92) and 65%(60/92), respectively in metastatic lymph node. The expression of integrin αvβ3 and CXCR4 in primary SCCHN (r=0.813, P<0.05) and lymph node metastasis (r=0.541, P<0.05) was positively correlated. Integrin αvβ3 and CXCR7 expression in primary SCCHN (r=0.683, P<0.05) and lymph node metastasis (r=0.708, P<0.05) was positively correlated. CXCR4 and CXCR7 expression in primary SCCHN (r=0.644, P<0.05) and lymph node metastasis (r=0.707, P<0.05) had a positive correlation. The expression level was associated with tumor size (P=0.040, 0.001, 0.009), lymph node metastasis (P=0.001, 0.000, 0.000) and surrounding tissue invasion (P=0.046, 0.002, 0.001), but not related to age (P=0.097, 0.274, 0.162), gender (P=0.103, 0.309, 0.187). Conclusions: The overexpression of integrin αvβ3, CXCR4 and CXCR7 in primary head and neck squamous carcinoma and metastatic lymph nodes was related to lymph node metastasis. The co-expression of integrin αvβ3, CXCR4 and CXCR7 may play a synergistic role in lymphatic metastasis of SCCHN.

αvβ3 Integrin and fibronectin expressions and their relation to estrogen and progesterone during placentation in swine

Mammalian pregnancy requires specific interactions between the conceptus and its mother that involve the endocrine system and adhesion molecules. The relation between adhesion molecules and their ligands at the fetal–maternal interface is crucial for developing a successful implantation. Progesterone (P4) and estrogen (E2) secreted by the porcine conceptus are required for the relation to be established. We investigated the expression of αvβ3 integrin and its ligand, fibronectin (FN), at the placental interface, and E2 and P4 concentrations in both serum and maternal and fetal placental extracts during placentation in swine. Placental and serum samples of crossbred sows at 17, 30, 60, 70, and 114 days gestation and no pregnant uteri were used. The presence of αvβ3 and FN were determined by immunohistochemistry, and E2 and P4 by chemiluminescence in homogenates of nonpregnant uterus (HoU), swine maternal placenta (HoPM), swine fetal placenta (HoPF) and serum. The expression of αvβ3 and FN increased at the interface at 17, 30 and 60 days gestation. Immunostaining decreased by 70 days. Serum E2 levels peaked at 17 days, then decreased, then increased again near term. The highest concentration of P4 occurred in HoPF at 70 days gestation, then decreased coincident with a decline in integrin and FN expression at the placental interface. High P4 levels during swine gestation may regulate the expression of αvβ3 integrin and FN at the placental interface for up to 70 days gestation. Other adhesion molecules and their ligands likely maintain the fetal–placental interface after 70 days.

Inhibition of the Integrin αVβ3 Improves the Immune and Anti-Lymphoma Effects of Bexarotene in Cutaneous T-Cell Lymphoma (CTCL)

Bexarotene (Bex) is an oral RXR agonist that is effective for the treatment of early and advanced-stage CTCL. However, Bex is associated with the unavoidable side effect of hypothyroidism in about 95% of pts, which is prophylactically managed with the administration of thyroid hormone (TH). Paradoxically, we found that physiological levels of TH increase the proliferation of CTCL by activating both the nuclear TRA receptor and the membrane integrin αVβ3 in these cells. Here, we determined the influence of TH replacement therapy on the anti-lymphoma activity of Bex, an unknown topic with clinical implications.Results: In standard culture conditions, Bex decreases the proliferation and viability of CTCL cell lines HuT78 and MJ. We conducted RNA-sequencing in HuT78 cells treated with Bex (vs. vehicle) to understand the mechanism/s underpinning these effects. We found that Bex regulates pathways related to “cell proliferation and differentiation” (e.g. REL, SCD, CCND1) and “immune system” (e.g. TBX21, IFNG, MX1) , which we independently validated. This suggests that Bex treatment could also impact anti-neoplastic immunity by increasing INF-gamma release from CTCL cells. We then conducted the same experiment culturing HuT78 and MJ in TH-depleted culture conditions and observed a higher effect of Bex in decreasing proliferation and viability; supporting the notion that Bex should not be administered with TH replacement. However, hypothyroidism is associated with marked immunosuppression that could favour CTCL progression and potentially affect the immune modulator effect of Bex that we described above.We thus determined the impact of TH replacement on the anti-lymphoma effect of Bex using a murine CTCL model. We implanted murine EL4 TCL cells in the hypodermis of immunocompetent C57BL/6 mice. Once tumors developed, mice were randomized into treatment with vehicle (Veh), Bex with no TH replacement (Bex) and Bex with TH replacement (BexT4+). TH replacement was done with oral administration of T4. We measured T4 in these mice plasma by RIA to assure that mice with T4 replacement reach physiological levels and those with no T4 develop hypothyroidism. Compared to Veh mice, the administration of Bex significantly decreased lymphoma growth in both conditions although slightly better in mice without T4 replacement (p<0.001 and p<0.01) for Bex and BexT4+, respectively). However, mice with Bex alone that developed hypothyroidism showed a significant decrease of CD8+CD44+ T-cells (p<0.05 vs. BexT4+) and increase of myeloid-derived suppressor cells in the tumor microenvironment and draining lymph nodes. Since infiltration of CD8+ cells decreases with CTCL progression, our data indicates that Bex treatment should be administered with T4 replacement to avoid a negative immune microenvironment.Considering the cellular effects of TH are exerted through TRA and integrin αVβ3 that can be independently modulated pharmacologically, we investigated whether integrin αVβ3 inhibition would be sufficient to blunt the TH-induced decrease on the antineoplastic efficacy of Bex. The lack of expression of integrin αVβ3 in normal T-cells offers a rationale for a selective effect on CTCL cells while sparing immune cells. In HuT78 and MJ cell lines, either αVβ3 silencing by siRNAs or pharmacologic inhibition with the clinical drug cilengitide avoided the decrease in the anti-CTCL effect of Bex upon TH supplementation. Moreover, gene expression analysis (RNA-seq and PCR) demonstrated that αVβ3 silencing induced higher (vs. Bex) up-regulation of “immune ” genes like TBX21 and INFG, or down-regulation of “proliferation” genes like REL and CCND1 .We thus tested if this mechanism can be therapeutically capitalized to improve Bex treatment in our CTCL murine model. We implanted 24 C57BL/6 mice with murine EL4 TCL cells and randomized them to vehicle (Veh), Bex with TH replacement in combination with cilengitide 40mg/kg (BexT4+Cil) or without cilengitide (BexT4+). At end of treatment, BexT4+Cil mice showed significantly smaller tumors compared with Veh and BexT4+ mice (p<0.001 and p<0.05, respectively). Importantly, the anti-tumoral immune response of CD8+CD44+ T-cells in the CTCL microenvironment and draining lymph nodes remained similar in BexT4+Cil vs. BexT4+ mice. Our data indicates that inhibition of the integrin αVβ3 is an effective strategy to improve Bex-based treatments in CTCL. DisclosuresCerchietti:Celgene: Research Funding; Lymphoma Research Foundation: Research Funding; Leukemia and Lymphoma Society: Research Funding; Weill Cornell Medicine - New York Presbyterian Hospital: Employment.

Macrovipecetin, a C-type lectin from Macrovipera lebetina venom, inhibits proliferation migration and invasion of SK-MEL-28 human melanoma cells and enhances their sensitivity to cisplatin

BackgroundThe resistance of melanoma cells to cisplatin restricts its clinical use. Therefore, the search for novel tumor inhibitors and effective combination treatments that sensitize tumor cells to this drug are still needed. We purified macrovipecetin, a novel heterodimeric C-type lectin, from Macrovipera lebetina snake venom and investigated its anti-tumoral effect on its own or combined with cisplatin, in human melanoma cells. MethodsBiochemical characterization, in vitro cells assays such as viability, apoptosis, adhesion, migration, invasion, Western blotting and in silico analysis were used in this study. ResultsMacrovipecetin decreased melanoma cell viability 100 times more than cisplatin. Interestingly, when combined with the drug, macrovipecetin enhanced the sensitivity of SK-MEL-28 cells by augmenting their apoptosis through increased expression of the apoptosis inducing factor (AIF) and activation of ERK1/2, p38, AKT and NF-κB. Moreover, macrovipecetin alone or combined with cisplatin induced the expression of TRADD, p53, Bax, Bim and Bad and down-regulated the Bcl-2 expression and ROS levels in SK-MEL-28 cells. Interestingly, these treatments impaired SK-MEL-28 cell adhesion, migration and invasion through modulating the function and expression of αvβ3 integrin along with regulating E-cadherin, vimentin, β-catenin, c-Src and RhoA expression. In silico study suggested that only the α chain of macrovipecetin interacts with a region overlapping the RGD motif binding site on this integrin. ConclusionsWe validated the antitumor effect of macrovipecetin when combined, or not, with cisplatin on SK-MEL-28 cells. General significanceThe presented work proposes the potential use of macrovipecetin and cisplatin in combination as an effective anti-melanoma treatment.

Curcumin mediated down-regulation of αV β3 integrin and up-regulation of pyruvate dehydrogenase kinase 4 (PDK4) in Erlotinib resistant SW480 colon cancer cells.

Erlotinib is a potent, selective, and orally active inhibitor of the epidermal growth factor receptor, but the development of erlotinib resistance during chemotherapy can lead to treatment failure. To shed light on the erlotinib-resistant pathway, this study investigated the effect of combination therapy using curcumin- and erlotinib-loaded nanoparticles on the expression of αv β3 integrin and pyruvate dehydrogenase kinase 4 (PDK4) in an erlotinib-resistant SW480 colon cancer cell line. An erlotinib-resistant SW480 colon cancer cell line was produced by long-term exposure to erlotinib. Curcumin-loaded Methoxy poly ethylene glycol Poly caprolactone (cur/mPEG-PCL) and erlotinib-loaded mPEG-PCL (erl/mPEG-PCL) micelles were provided using a single step nanoprecipitation method and used as combination therapy of resistant SW480 cancer cells. After that, gene expression levels of PDK4, αv, and β3 mRNA were determined by the semiquantitative reverse transcription-polymerase chain reaction. Protein levels of whole αv β3 integrin were evaluated using the enzyme-linked immunosorbent assay method. In SW480 cell line, the IC50 of nonresistant and resistant cells was 87.6±1.2nM and 19.1±0.14μM, for erlotinib and it was about 21.8 and 30μM for curcumin, respectively. Although PDK4 expression was not significantly different in resistant and nonresistant cells, its expression was up regulated (1.4 fold) in resistant cells by a combination therapy of cur/mPEG-PCL at a dose of 3μM and erl/mPEG-PCL at a dose of 5μM. β3 mRNA and the protein level of whole αv β3 integrin was significantly higher in resistant SW480 cells as compared with those in nonresistant cells. In terms of treatment, a combination of 6-μM cur/mPEG-PCL and 5-μM erl/mPEG-PCL down regulated β3 gene expression 6.6-fold in resistant cells as compared with nonresistant cells. At the protein level, a combination of 3-μM-cur/mPEG-PCL and 10-μM erl/mPEG-PCL reduced αv β3 protein in resistant cells. The results indicated that combination therapy using cur/mPEG-PCL and erl/mPEG-PCL could decrease αv β3 integrin expression and increase PDK4 gene expression in resistant colon cancer cells, which may have effects on drug resistance signaling pathways.

Bone-Induced Expression of Integrin β3 Enables Targeted Nanotherapy of Breast Cancer Metastases

Bone metastases occur in approximately 70% of metastatic breast cancer patients, often leading to skeletal injuries. Current treatments are mainly palliative and underscore the unmet clinical need for improved therapies. In this study, we provide preclinical evidence for an antimetastatic therapy based on targeting integrin β3 (β3), which is selectively induced on breast cancer cells in bone by the local bone microenvironment. In a preclinical model of breast cancer, β3 was strongly expressed on bone metastatic cancer cells, but not primary mammary tumors or visceral metastases. In tumor tissue from breast cancer patients, β3 was significantly elevated on bone metastases relative to primary tumors from the same patient (n = 42). Mechanistic investigations revealed that TGFβ signaling through SMAD2/SMAD3 was necessary for breast cancer induction of β3 within the bone. Using a micelle-based nanoparticle therapy that recognizes integrin αvβ3 (αvβ3-MPs of ∼12.5 nm), we demonstrated specific localization to breast cancer bone metastases in mice. Using this system for targeted delivery of the chemotherapeutic docetaxel, we showed that bone tumor burden could be reduced significantly with less bone destruction and less hepatotoxicity compared with equimolar doses of free docetaxel. Furthermore, mice treated with αvβ3-MP-docetaxel exhibited a significant decrease in bone-residing tumor cell proliferation compared with free docetaxel. Taken together, our results offer preclinical proof of concept for a method to enhance delivery of chemotherapeutics to breast cancer cells within the bone by exploiting their selective expression of integrin αvβ3 at that metastatic site. Cancer Res; 77(22); 6299-312. ©2017 AACR.

Chemodrug delivery using integrin-targeted PLGA-Chitosan nanoparticle for lung cancer therapy

In this study, we report the efficacy of RGD (arginine-glycine-aspartic acid) peptide-modified polylactic acid-co-glycolic acid (PLGA)-Chitosan nanoparticle (CSNP) for integrin αvβ3 receptor targeted paclitaxel (PTX) delivery in lung cancer cells and its impact on normal cells. RGD peptide-modified chitosan was synthesized and then coated onto PTX-PLGA nanoparticles prepared by emulsion-solvent evaporation. PTX-PLGA-CSNP-RGD displayed favorable physicochemical properties for a targeted drug delivery system. The PTX-PLGA-CSNP-RGD system showed increased uptake via integrin receptor mediated endocytosis, triggered enhanced apoptosis, and induced G2/M cell cycle arrest and more overall cytotoxicity than its non-targeted counterpart in cancer cells. PTX-PLGA-CSNP-RGD showed less toxicity in lung fibroblasts than in cancer cells, may be attributed to low drug sensitivity, nevertheless the study invited close attention to their transient overexpression of integrin αvβ3 and cautioned against corresponding uptake of toxic drugs, if any at all. Whereas, normal human bronchial epithelial (NHBE) cells with poor integrin αvβ3 expression showed negligible toxicity to PTX-PLGA-CSNP-RGD, at equivalent drug concentrations used in cancer cells. Further, the nanoparticle demonstrated its capacity in targeted delivery of Cisplatin (CDDP), a drug having physicochemical properties different to PTX. Taken together, our study demonstrates that PLGA-CSNP-RGD is a promising nanoplatform for integrin targeted chemotherapeutic delivery to lung cancer.

Effect of human amniotic epithelial cells on pro-fibrogenic resident hepatic cells in a rat model of liver fibrosis.

Myofibroblasts are key fibrogenic cells responsible for excessive extracellular matrix synthesis characterizing the fibrotic lesion. In liver fibrosis, myofibroblasts derive either from activation of hepatic stellate cells (HSC) and portal fibroblasts (PF), or from the activation of fibroblasts that originate from ductular epithelial cells undergoing epithelial–mesenchymal transition. Ductular cells can also indirectly promote myofibroblast generation by activating TGF‐β, the main fibrogenic growth factor, through αvβ6 integrin. In addition, after liver injury, liver sinusoidal cells can lose their ability to maintain HSC quiescence, thus favouring HSC differentiation towards myofibroblasts. The amniotic membrane and epithelial cells (hAEC) derived thereof have been shown to decrease hepatic myofibroblast levels in rodents with liver fibrosis. In this study, in a rat model of liver fibrosis, we investigated the effects of hAEC on resident hepatic cells contributing to myofibroblast generation. Our data show that hAEC reduce myofibroblast numbers with a consequent reduction in fibronectin and collagen deposition. Interestingly, we show that hAEC strongly act on specific myofibroblast precursors. Specifically, hAEC reduce the activation of PF rather than HSC. In addition, hAEC target reactive ductular cells by inhibiting their proliferation and αvβ6 integrin expression, with a consequent decrease in TGF‐β activation. Moreover, hAEC counteract the transition of ductular cells towards fibroblasts, while it does not affect injury‐induced and fibrosis‐promoting sinusoidal alterations. In conclusion, among the emerging therapeutic applications of hAEC in liver diseases, their specific action on PF and ductular cells strongly suggests their application in liver injuries involving the expansion and activation of the portal compartment.