Human Acellular Amniotic Matrix with Previously Seeded Umbilical Cord Mesenchymal Stem Cells Restores Endometrial Function in a Rat Model of Injury.

BACKGROUND: Abnormal endometrial repair after injury results in the formation of intrauterine adhesions (IUA) and a thin endometrium, which are key causes for implantation failure and infertility. Stem cell transplantation offers a potential alternative for some cases of severe Asherman's syndrome that cannot be treated with surgery or hormonal therapy. Umbilical cord-derived mesenchymal stem cells (UCMSCs) have been reported to repair the damaged endometrium. However, there is no report on the effects of UCMSCs previously seeded on human acellular amniotic matrix (AAM) on endometrial injury. METHODS: Absolute ethanol was injected into rat uteri to damage the endometrium. UCMSCs previously seeded on AAM were surgically transplanted. Using a variety of methods, the treatment response was assessed by endometrial thickness, endometrial biomarker expression, endometrial receptivity, cell proliferation, and inflammatory factors. RESULTS: Endometrial thickness was markedly improved after UCMSC-AAM transplantation. The expression of endometrial biomarkers, namely, vimentin, cytokeratin, and integrin ß3, in treated rats increased compared with untreated rats. In the UCMSC-AAM group, the VEGF expression decreased, whereas that of MMP9 increased compared with the injury group. Moreover, in the AAM group, the MMP9 expression increased. The expression of proinflammatory factors (IL-2, TNFα, and IFN-γ) in the UCMSC-AAM group decreased compared with the untreated group, whereas the expression of anti-inflammatory factors (IL-4, IL-10) increased significantly. CONCLUSIONS: UCMSC transplantation using AAM as the carrier can be applied to treat endometrial injury in rats. The successful preparation of lyophilized AAM provides the possibility of secondary infectious disease screening and amniotic matrix quality detection, followed by retrospective analysis. The UCMSC-AAM complex may promote the better application of UCMSCs on the treatment of injured endometrium.

A peptide derived from chaperonin 60.1, IRL201104, inhibits LPS-induced acute lung inflammation.

Chaperonin 60.1 (Cpn60.1) is a protein derived from Mycobacterium tuberculosis that has been shown, along with its peptide fragment IRL201104, to have beneficial effects in models of allergic inflammation. To further investigate the anti-inflammatory properties of Cpn60.1 and IRL201104, we have investigated these molecules in a model of nonallergic lung inflammation. Mice were treated with Cpn60.1 (0.5-5,000 ng/kg) or IRL201104 (0.00025-2.5 ng/kg), immediately before intranasal instillation of bacterial lipopolysaccharide (LPS). Cytokine levels and cell numbers in mouse bronchoalveolar lavage (BAL) fluid were measured 4 h after LPS administration. In some experiments, mice were depleted of lung-resident phagocytes. Cells from BAL fluid were analyzed for inflammasome function. Human umbilical vein endothelial cells (HUVECs) were analyzed for adhesion molecule expression. Human neutrophils were analyzed for integrin expression, chemotaxis, and cell polarization. Cpn60.1 and IRL201104 significantly inhibited neutrophil migration into the airways, independently of route of administration. This effect of the peptide was absent in TLR4 and annexin A1 knockout mice. Intravital microscopy revealed that IRL201104 reduced leukocyte adhesion and migration into inflamed tissues. However, IRL201104 did not significantly affect adhesion molecule expression in HUVECs or integrin expression, chemotaxis, or polarization of human neutrophils at the studied concentrations. In phagocyte-depleted animals, the anti-inflammatory effect of IRL201104 was not significant. IRL201104 significantly reduced IL-1ß and NLRP3 expression and increased A20 expression in BAL cells. This study shows that Cpn60.1 and IRL201104 potently inhibit LPS-induced neutrophil infiltration in mouse lungs by a mechanism dependent on tissue-resident phagocytes and to a much lesser extent, the proresolving factor annexin A1.

Bile acid-activated macrophages promote biliary epithelial cell proliferation through integrin αvß6 upregulation following liver injury.

Cholangiopathies caused by biliary epithelial cell (BEC) injury represent a leading cause of liver failure. No effective pharmacologic therapies exist, and the underlying mechanisms remain obscure. We aimed to explore the mechanisms of bile duct repair after targeted BEC injury. Injection of intermedilysin into BEC-specific human CD59 (hCD59) transgenic mice induced acute and specific BEC death, representing a model to study the early signals that drive bile duct repair. Acute BEC injury induced cholestasis followed by CCR2+ monocyte recruitment and BEC proliferation. Using microdissection and next-generation RNA-Seq, we identified 5 genes, including Mapk8ip2, Cdkn1a, Itgb6, Rgs4, and Ccl2, that were most upregulated in proliferating BECs after acute injury. Immunohistochemical analyses confirmed robust upregulation of integrin αvß6 (ITGß6) expression in this BEC injury model, after bile duct ligation, and in patients with chronic cholangiopathies. Deletion of the Itgb6 gene attenuated BEC proliferation after acute bile duct injury. Macrophage depletion or Ccr2 deficiency impaired ITGß6 expression and BEC proliferation. In vitro experiments revealed that bile acid-activated monocytes promoted BEC proliferation through ITGß6. Our data suggest that BEC injury induces cholestasis, monocyte recruitment, and induction of ITGß6, which work together to promote BEC proliferation and therefore represent potential therapeutic targets for cholangiopathies.

Integrin expression in correlation to clinicopathological features and prognosis of prostate cancer: A systematic review and meta-analysis.

BACKGROUND: The prompt identification of patients with poor prognosis is essential in order to improve the treatment outcomes in prostate cancer (CaP); as a novel approach, several molecular markers, including integrins, have been discussed as prognostic biomarkers. Our aim was to comprehensively examine aberrant expression of integrins in correlation with clinicopathological features and prognosis in CaP by synthesizing all available evidence, in a systematic review and meta-analysis. METHODS: A systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Scientific literature databases (Pubmed, Embase, and Scopus) were systematically searched until May 10, 2020. Random-effects (DerSimonian-Laird) models were used to estimate pooled odds ratios (ORs) for cross-sectional correlations with clinicopathological characteristics and relative risks for longitudinal associations with prognosis. RESULTS: Fourteen studies were included with a total number of 3,194 CaP cases examined (13 cross-sectional and four longitudinal cohort study arms). Correlation of low expression of α6 (pooled OR = 0.10, 95% confidence interval [CI]: 0.04-0.28, P < 0.001) and ß1 (pooled OR = 0.45; 95% CI: 0.21-1.00, P = 0.049) integrin with high Gleason score was noted. A borderline trend between reduced expression of α6 integrin and an advanced clinical stage of CaP (pooled OR = 0.48; 95% CI: 0.22-1.03, P = 0.06) was observed. No associations with biochemical recurrence and survival were documented. CONCLUSIONS: Evidence on the association of low expression of integrins α6 and ß1 and more advanced CaP exist, whereas significant results on survival were not documented; further studies are warranted.

Limitations of cell-lineage-specific non-dynamic gene recombination in CD11c.Cre+ITGA4fl/fl mice.

BACKGROUND: The Cre-lox system is a non-dynamic method of gene modification and characterization. Promoters thought to be relatively cell-specific are utilized for generation of cell-lineage-specific gene modifications. METHODS: CD11c.Cre+ITGA4fl/fl mice were generated to abolish the expression of ITGA (α4-integrin) in CD11c+ cells. Ex vivo flow cytometry studies were used to assess the expression of cellular surface markers in different lymphoid compartments and leukocytes subsets after Cre-mediated recombination. RESULTS: A significant reduction of α4-integrin expression among CD11c+- cells was achieved in CD11c.Cre+ITGA4fl/fl mice in primary and secondary lymphoid tissues. A similar reduction in the expression of α4-integrin was also observed in CD11c- cells. CONCLUSION: Cre-lox-mediated cell lineage-specific gene deletion is limited by the transient expression of recombination regulating sequences in hematopoietic cell lines. These methodological issues indicate the need to consider when to employ non-dynamic DNA recombination models in animal models of CNS autoimmunity. An experimental algorithm to address the biological complexities of non-dynamic gene recombination is provided.

Integrin-α9 and Its Corresponding Ligands Play Regulatory Roles in Chronic Periodontitis.

Integrin-α9 (ITGA9) and its corresponding ligands are involved in inflammatory and immune responses. The present study aimed to investigate whether ITGA9 participates in the development of chronic periodontitis (ChP) and to explore the underlying mechanisms. We collected gingival tissue and gingival crevicular fluid in vivo from patients to determine the levels of ITGA9 and its ligands. We cultured primary periodontal ligament cells (PDLCs) in vitro and applied small interfering RNA to knock down ITGA9 in order to analyze the changes of inflammatory cytokines and explore the related cellular signaling pathways. The expression level of ITGA9 was significantly higher in the gingiva of patients with ChP than that of healthy individuals. ITGA9 knockdown in the PDLCs inhibited the secretion of interleukin (IL)-1ß, IL-6, and IL-8. Western blot analysis indicated that this change could be attributed to the regulation of the mitogen-activated protein kinase (MAPK) signaling pathway. ITGA9 plays a regulatory role in the homeostasis of ChP. The results of the present study provide potential insights into the treatment of periodontitis. Graphical abstract.

Integrin α11ß1 is expressed in breast cancer stroma and associates with aggressive tumor phenotypes.

Cancer-associated fibroblasts are essential modifiers of the tumor microenvironment. The collagen-binding integrin α11ß1 has been proposed to be upregulated in a pro-tumorigenic subtype of cancer-associated fibroblasts. Here, we analyzed the expression and clinical relevance of integrin α11ß1 in a large breast cancer series using a novel antibody against the human integrin α11 chain. Several novel monoclonal antibodies against the integrin α11 subunit were tested for use on formalin-fixed paraffin-embedded tissues, and Ab 210F4B6A4 was eventually selected to investigate the immunohistochemical expression in 392 breast cancers using whole sections. mRNA data from METABRIC and co-expression patterns of integrin α11 in relation to αSMA and cytokeratin-14 were also investigated. Integrin α11 was expressed to varying degrees in spindle-shaped cells in the stroma of 99% of invasive breast carcinomas. Integrin α11 co-localized with αSMA in stromal cells, and with αSMA and cytokeratin-14 in breast myoepithelium. High stromal integrin α11 expression (66% of cases) was associated with aggressive breast cancer features such as high histologic grade, increased tumor cell proliferation, ER negativity, HER2 positivity, and triple-negative phenotype, but was not associated with breast cancer specific survival at protein or mRNA levels. In conclusion, high stromal integrin α11 expression was associated with aggressive breast cancer phenotypes.

Lineage marker expression on mouse hematopoietic stem cells.

Whether hematopoietic stem cells (HSCs) express lineage markers is controversial. In this study, we highly purified HSCs from the adult bone marrow of C57BL/6 mice and examined their gene expression and reconstitution potential. We first focused on the integrin family. Single-cell reverse transcription polymerase chain reaction revealed that the expression of ItgaM/Itgb2 (Mac-1) and Itga2b/Itgb3 (CD41/CD61) gradually increased along HSC differentiation, whereas Itga4, Itga5, Itga6, and ItgaV (CD51) together with Itgb1 were highly expressed in both HSCs and hematopoietic progenitor cells (HPCs). We next fractionated HSCs based on their expression of Mac-1, CD41, and CD51 by flow cytometry. We detected Mac-negative and Mac-low, but not Mac-high cells, in the HSC population. We also detected CD41-negative, -low, and -high cells in the HSC population. Competitive repopulation revealed that Mac-1-negative and -low HSCs were functionally similar, and CD41-negative and -low HSCs were functionally similar, at the single-cell level, but CD41-high HSCs were not detectable. We then found that the selection of Mac-1-negative HSCs or CD41-negative HSCs had no advantage in HSC purification. We moreover found that HSCs expressed more CD51 than CD41, and HPCs expressed more CD41 than CD51, suggesting that CD51 expression was gradually replaced by CD41 expression during megakaryocyte differentiation. We concluded that low levels of Mac-1 and CD41 expression are irrelevant to the self-renewal and differentiation potentials in HSCs.

Heparan sulfate proteoglycan, integrin, and syndecan-4 are mechanosensors mediating cyclic strain-modulated endothelial gene expression in mouse embryonic stem cell-derived endothelial cells.

It is widely believed that the differentiation of embryonic stem cells (ESCs) into viable endothelial cells (ECs) for use in vascular tissue engineering can be enhanced by mechanical forces. In our previous work, we reported that shear stress enhanced important EC functional genes on a CD31+ /CD45- cell population derived from mouse ESC committed to the EC lineage. In the present study, in contrast to the effects of shear stress on this cell population, we observed that cyclic strain significantly reduced the expression of EC-specific marker genes (vWF, VE-cadherin, and PECAM-1), tight junction protein genes (ZO-1, OCLD, and CLD5), and vasoactive genes (eNOS and ET1), while it did not alter the expression of COX2. Taken together, these studies indicate that only shear stress, not cyclic strain, is a useful mechanical stimulus for enhancing the properties of CD31+ /CD45- cells for use as EC in vascular tissue engineering. To begin examining the mechanisms controlling cyclic strain-induced suppression of gene expression in CD31+ /CD45- cells, we depleted the heparan sulfate (HS) component of the glycocalyx, blocked integrins, and silenced the HS proteoglycan syndecan-4 in separate experiments. All of these treatments resulted in the reversal of cyclic strain-induced gene suppression. The current study and our previous work provide a deeper understanding of the mechanisms that balance the influence of cyclic strain and shear stress in endothelial cells.

Expression of Interleukin-6 and Integrin ανß6 in Colon Cancer: Association with Clinical Outcomes and Prognostic Implications.

As important factors in the tumor microenvironment, interleukin-6 (IL-6) and integrin ανß6 play significant roles in accumulating mutations that drive the progression and metastatic capacities of cancer. The aim of this study was to investigate the expression of IL-6 and integrin ανß6, their clinical significance, as well as their correlation in the colon cancer tissues of 145 cases using immunohistochemistry. Our results showed that IL-6 and integrin ανß6 are indicators of cancer progression and poor prognosis in patients with colon cancer. Moreover, their relationship may provide clues for further studies on how the tumor microenvironment mediates the development of colon cancer, as well as strategies for the identification of novel therapeutic targets in the prevention and treatment of colon cancer.

MAIT Cells Upregulate α4ß7 in Response to Acute Simian Immunodeficiency Virus/Simian HIV Infection but Are Resistant to Peripheral Depletion in Pigtail Macaques.

Mucosal-associated invariant T (MAIT) cells are nonconventional T lymphocytes that recognize bacterial metabolites presented by MR1. Whereas gut bacterial translocation and the loss/dysfunction of peripheral MAIT cells in HIV infection is well described, MAIT cells in nonhuman primate models are poorly characterized. We generated a pigtail macaque (PTM)-specific MR1 tetramer and characterized MAIT cells in serial samples from naive and SIV- or simian HIV-infected PTM. Although PTM MAIT cells generally resemble the phenotype and transcriptional profile of human MAIT cells, they exhibited uniquely low expression of the gut-homing marker α4ß7 and were not enriched at the gut mucosa. PTM MAIT cells responded to SIV/simian HIV infection by proliferating and upregulating α4ß7, coinciding with increased MAIT cell frequency in the rectum. By 36 wk of infection, PTM MAIT cells were activated and exhibited a loss of Tbet expression but were not depleted as in HIV infection. Our data suggest the following: 1) MAIT cell activation and exhaustion is uncoupled from the hallmark depletion of MAIT cells during HIV infection; and 2) the lack of PTM MAIT cell enrichment at the gut mucosa may prevent depletion during chronic infection, providing a model to assess potential immunotherapeutic approaches to modify MAIT cell trafficking during HIV infection.

Epstein-Barr Virus Induces Expression of the LPAM-1 Integrin in B Cells In Vitro and In Vivo.

Epstein-Barr virus (EBV) infects the oropharynx but, surprisingly, frequently induces B cell proliferation in the gut of immunosuppressed individuals. We found that EBV infection in vitro induces the expression of the LPAM-1 integrin on tonsillar B cells and increases it on peripheral blood cells. Similarly, LPAM-1 was induced in the tonsils of patients undergoing primary infectious mononucleosis. EBV-induced LPAM-1 bound to the MAdCAM-1 addressin, which allows B cell homing to the gastrointestinal mucosa-associated lymphoid tissue (GALT). Thus, we hypothesized that EBV-induced LPAM-1 could induce relocation of infected B cells from the tonsil to the GALT. In situ hybridization with an EBER-specific probe revealed the frequent presence of EBV-infected cells in the pericolic lymph nodes of healthy individuals. Relocation of infected B cells into the GALT would expand the EBV reservoir, possibly protecting it from T cells primed in the oropharynx, and explain why EBV induces lymphoid tumors in the gut.IMPORTANCE EBV causes tumors in multiple organs, particularly in the oro- and nasopharyngeal area but also in the digestive system. This virus enters the body in the oropharynx and establishes a chronic infection in this area. The observation that the virus causes tumors in the digestive system implies that the infected cells can move to this organ. We found that EBV infection induces the expression of integrin beta 7 (ITGB7), an integrin that associates with integrin alpha 4 to form the LPAM-1 dimer. LPAM-1 is key for homing of B cells to the gastrointestinal tract, suggesting that induction of this molecule is the mechanism through which EBV-infected cells enter this organ. In favor of this hypothesis, we could also detect EBV-infected cells in the lymph nodes adjacent to the colon and in the appendix.

Integrin α5 down-regulation by miR-205 suppresses triple negative breast cancer stemness and metastasis by inhibiting the Src/Vav2/Rac1 pathway.

Triple negative breast cancer (TNBC) usually displays more aggressive metastasis, the underlying mechanism is unclear. Previous studies showed that microRNA-205 (miR-205) has controversial roles in cancer, however, its role in TNBC metastasis and the underlying mechanism have not been well-understood. In this study we found that miR-205 expression level is extremely low in basal mesenchymal-like highly migratory and invasive TNBC cells. Stably re-expressing miR-205 in TNBC cells significantly reduced their migration, invasion capability and cancer stem cell (CSC)-like property. Nude mouse orthotopic mammary xenograft tumor model study revealed that miR-205 re-expression greatly decreases TNBC tumor growth and abolishes spontaneous lung metastasis. Mechanistic studies demonstrated that miR-205 inhibits TNBC cell metastatic traits and tumor metastasis by down-regulating integrin α5 (ITGA5). Moreover, ITGA5 knockout using the CRISPR/Cas9 technique achieved the same strong inhibitory effect on TNBC cell CSC-like property and tumor metastasis as re-expressing miR-205 did. Further mechanistic studies indicated that ITGA5 down-regulation by miR-205 re-expression impairs TNBC cell metastatic traits by inhibiting the Src/Vav2/Rac1 pathway. Together, our findings suggest that miR-205 and ITGA5 may serve as potential targets for developing effective therapies for metastatic TNBC.

Kallikrein-related peptidase 7 overexpression in melanoma cells modulates cell adhesion leading to a malignant phenotype.

We recently reported that human melanoma cells, but not benign melanocytes, aberrantly express kallikrein-related peptidase 7 (KLK7). Here, we show a KLK7 overexpression-mediated decrease of cell adhesion to extracellular matrix binding proteins, associated with downregulation of α5/ß1/αv/ß3 integrin expression. We also report an up-regulation of MCAM/CD146 and an increase in spheroid formation of these cells. Our results demonstrate that aberrant KLK7 expression leads to a switch to a more malignant phenotype suggesting a potential role of KLK7 in melanoma invasion. Thus, KLK7 may represent a biomarker for melanoma progression and may be a potential therapeutic target for melanoma.

Transforming growth factor ß1 enhances adhesion of endometrial cells to mesothelium by regulating integrin expression.

Endometriosis is the abnormal growth of endometrial cells outside the uterus, causing pelvic pain and infertility. Furthermore, adhesion of endometrial tissue fragments to pelvic mesothelium is required for the initial step of endometriosis formation outside uterus. TGF-ß1 and adhesion molecules importantly function for adhesion of endometrial tissue fragments to mesothelium outside uterus. However, the function of TGF-ß1 on the regulation of adhesion molecule expression for adhesion of endometrial tissue fragments to mesothelium has not been fully elucidated. Interestingly, transforming growth factor ß1 (TGF-ß1) expression was higher in endometriotic epithelial cells than in normal endometrial cells. The adhesion efficiency of endometriotic epithelial cells to mesothelial cells was also higher than that of normal endometrial cells. Moreover, TGF-ß1 directly induced the adhesion of endometrial cells to mesothelial cells through the regulation of integrin of αV, α6, ß1, and ß4 via the activation of the TGF-ß1/TGF-ßRI/Smad2 signaling pathway. Conversely, the adhesion of TGF-ß1-stimulated endometrial cells to mesothelial cells was clearly reduced following treatment with neutralizing antibodies against specific TGF-ß1-mediated integrins αV, ß1, and ß4 on the endometrial cell membrane. Taken together, these results suggest that TGF-ß1 may act to promote the initiation of endometriosis by enhancing integrin-mediated cell-cell adhesion. [BMB Reports 2017; 50(8): 429-434].

The impact of quercetin on wound healing relates to changes in αV and ß1 integrin expression.

Overly fibrotic wound healing can lead to excess scar formation, causing functional impairment and undesirable cosmetic results. However, there are few successful treatments available to prevent or remediate scars. This study sought to explore the molecular mechanisms by which quercetin, a naturally-occurring antifibrotic agent, diminishes scar formation. Using both mice and fibroblast cells, we examined quercetin's impact on fibrosis and the wound healing rate, and potential molecular mechanisms underlying the quercetin-mediated reduction of fibrosis. While cultured fibroblasts demonstrated normal growth in response to quercetin, quercetin increased surface αV integrin and decreased ß1 integrin. These changes in surface integrin expression may impact factors that contribute to fibrosis including cell migration, proliferation, and extracellular matrix production. In both quercetin-treated and control mice, wounds healed in about 14 days. Masson's trichrome stain revealed diminished fibrosis at the wound site in quercetin-treated animals despite the normal healing rate, indicating the potential for better cosmetic results without delaying healing. An in vitro scratch wound model using cells plated on an artificial extracellular matrix demonstrated delayed closure following quercetin treatment. The extracellular matrix also ameliorated quercetin's effect on αV integrin. Thus, αV integrin recruitment in response to quercetin treatment may promote the quercetin-mediated decrease extracellular matrix because cells require less extracellular matrix to migrate into a wound. With added extracellular matrix, ß1 integrin remained diminished in response to quercetin, indicating that quercetin's effect on ß1 integrin expression is independent of extracellular matrix -mediated signaling and is likely driven by inhibition of the intracellular mechanisms driving ß1 expression. These findings suggest that quercetin could alter the cells' interactions with the extracellular matrix through the regulation of integrin expression to promote a decrease in fibrosis. Furthermore, this work demonstrates that this naturally occurring and commercially available supplement could be used to improve wound healing by impacting integrin expression, leading to a lower extracellular matrix requirement to achieve healing. Impact statement Scar formation during wound healing can be problematic for patients but there are limited therapies available to treat or prevent excess fibrosis at wound sites. This work examines the impact of quercetin, a flavonoid that decreases fibrosis, on wound healing, and relates quercetin's effects to changes in integrin expression on the surface of fibroblast cells. To our knowledge, this is the first report that quercetin alters integrin expression or that this impact may be part of the mechanism by which quercetin prevents fibrosis. This work demonstrates that quercetin can be used to modulate integrin expression and that this effect may in turn reduce fibrosis during wound healing. Furthermore, this paper identifies the modulation of integrin expression as a possible therapeutic target in preventing scars. This information could be used to improve therapeutics to aid in the cosmetic and functional results following wound healing.

Hypoxia upregulates integrin gene expression in microvascular endothelial cells and promotes their migration and capillary-like tube formation.

Tissue hypoxia affects gene expression through the hypoxia-inducible transcription factors, HIF-1 and HIF-2, in both physiological and pathological angiogenesis. Angiogenesis is a complex response of endothelial cells integrating cell proliferation, migration, tube formation, and their interaction with the extracellular matrix through integrin receptors. In this report, we studied the effect of hypoxia on the angiogenic functions of human microvascular endothelial cells (HMEC-1) as well as on expression of the angiogenic integrins αν ß3 , αν ß5 , and α5 ß1 . Exposure of HMEC-1 to hypoxia (1% O2 ) or to DMOG, a prolyl-4-hydroxylase inhibitor, caused significant reduction to their proliferation rate, whereas their migration ability toward laminin-1 or collagen IV and capillary-like tube formation were significantly enhanced. In addition, αv , ß1 , ß3 , and ß5 integrins expression was increased under hypoxia in HMEC-1, while α5 integrin was not affected. Both HIF-1 and HIF-2 protein expression and transcriptional activity were induced under hypoxia in HMEC-1. The knockdown of either HIF-1α or HIF-2α inhibited integrin ß3 hypoxic stimulation, suggesting a HIF-dependent induction of ß3 integrin in HMEC-1. Taken together, our results indicate that hypoxia transcriptionally up-regulates angiogenic integrins in microvascular endothelial cells along with promoting migration and tube formation of HMEC-1.

HR+HER2- breast cancers with growth factor receptor-mediated EMT have a poor prognosis and lapatinib downregulates EMT in MCF-7 cells.

Despite an overall good prognosis, a significant proportion of patients with hormone receptor positive human epidermal growth factor receptor 2 negative breast cancers develop distant metastases. The metastatic potential of epithelial cells is known to be regulated by tumor-stromal interaction and mediated by epithelial-to-mesenchymal transition. Hormone receptor positive human epidermal growth factor receptor 2 negative tumors were used to estimate markers of epithelial-to-mesenchymal transition, and the luminal breast cancer cell line MCF-7 was used to examine the interactions between integrins and growth factor receptors in causation of epithelial-to-mesenchymal transition. A total of 140 primary tumors were sub-divided into groups enriched for the markers of epithelial-to-mesenchymal transition (snail family transcriptional repressor 2 and integrin ß6) versus those with low levels. Within the epithelial-to-mesenchymal transition+ tumors, there was a positive correlation between the transcripts of integrin ß6 and growth factor receptors-human epidermal growth factor receptor 2 and epidermal growth factor receptor. In tumors enriched for epithelial-to-mesenchymal transition markers, patients with tumors with the highest quartile of growth factor receptor transcripts had a shorter disease-free survival compared to patients with low growth factor receptor expression by Kaplan-Meier analysis (log rank, p = 0.03). Epithelial-to-mesenchymal transition was induced in MCF-7 cells by treatment with transforming growth factor beta 1 and confirmed by upregulation of SNAI1 and SNAI2 transcripts, increase of vimentin and integrin ß6 protein, and repression of E-cadherin. Treatment of these cells with the dual-specificity tyrosine-kinase inhibitor lapatinib led to downregulation of epithelial-to-mesenchymal transition as indicated by lower levels of SNAI1 and SNAI2 transcripts, integrin αvß6, and matrix metalloproteinase 9 protein. The results suggest that synergistic interactions between growth factor receptors and integrin ß6 could mediate epithelial-to-mesenchymal transition and migration in a subset of luminal breast cancers and lapatinib might be effective in disrupting this interaction.

Award Winner in the Young Investigator Category, 2017 Society for Biomaterials Annual Meeting and Exposition, Minneapolis, MN, April 05-08, 2017: Lymph node stiffness-mimicking hydrogels regulate human B-cell lymphoma growth and cell surface receptor expression in a molecular subtype-specific manner.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma, with multiple molecular subtypes. The activated B-cell-like DLBCL subtype accounts for roughly one-third of all the cases and has an inferior prognosis. There is a need to develop better class of therapeutics that could target molecular pathways in resistant DLBCLs; however, this requires DLBCLs to be studied in representative tumor microenvironments. The pathogenesis and progression of lymphoma has been mostly studied from the point of view of genetic alterations and intracellular pathway dysregulation. By comparison, the importance of lymphoma microenvironment in which these malignant cells arise and reside has not been studied in as much detail. We have recently elucidated the role of integrin signaling in lymphomas and demonstrated that inhibition of integrin-ligand interactions abrogated the proliferation of malignant cells in vitro and in patient-derived xenograft. Here we demonstrate the role of lymph node tissue stiffness on DLBCL in a B-cell molecular subtype specific manner. We engineered tunable bioartificial hydrogels that mimicked the stiffness of healthy and neoplastic lymph nodes of a transgenic mouse model and primary human lymphoma tumors. Our results demonstrate that molecularly diverse DLBCLs grow differentially in soft and high stiffness microenvironments, which further modulates the integrin and B-cell receptor expression level as well as response to therapeutics. We anticipate that our findings will be broadly useful to study lymphoma biology and discover new class of therapeutics that target B-cell tumors in physical environments. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1833-1844, 2017.