Expression Of Integrin Β1 Research Articles

High matrix stiffness accelerates migration of hepatocellular carcinoma cells through the integrin β1-Plectin-F-actin axis

BackgroundAbundant research indicates that increased extracellular matrix (ECM) stiffness significantly enhances the malignant characteristics of hepatocellular carcinoma (HCC) cells. Plectin, an essential cytoskeletal linker protein, has recently emerged as a promoter of cancer progression, particularly in the context of cancer cell invasion and metastasis. However, the responsiveness of plectin to changes in ECM stiffness and its impact on HCC progression remain unclear. In this study, we aimed to investigate whether plectin responds to variations in ECM stiffness and to explore its involved molecular mechanisms in regulating HCC cell migration.ResultsOur results showed that, when compared with control group (7 kPa), high ECM stiffness (53 kPa) boosts HCC cell migration by upregulating plectin and integrin β1 expression and increasing F-actin polymerization. Knockdown of integrin β1 negated the high stiffness-upregulated plectin expression. Furthermore, reducing either plectin or integrin β1 levels, or using latrunculin A, effectively prevented the high ECM stiffness-induced F-actin polymerization and HCC cell migration.ConclusionsThese findings demonstrate that integrin β1-plectin-F-actin axis is necessary for high matrix stiffness-driven migration of HCC cells, and provide evidence for the critical role of plectin in mechanotransduction in HCC cells.

Gingival keratinocyte adhesion on atomic layer-deposited hydroxyapatite coated titanium.

This study aimed to evaluate the effects of the atomic layer deposited hydroxyapatite (ALD-HA) coating of the titanium (Ti) surface on human gingival keratinocyte (HGK) cell adhesion, spreading, viability, and hemidesmosome (HD) formation. Grade 2 square-shaped Ti substrates were used (n = 62). Half of the substrates were ALD-HA coated, while the other half were used as non-coated controls (NC). The ALD-HA surface was characterized with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis. The initial cell adhesion and HD formation of HGKs were evaluated after a 24-h cultivation period. The cell proliferation was assessed by cultivating cells for 1, 3, and 7d. The expression levels of the integrin mediating cell adhesion were detected with the Western Blot method. In addition, cell spreading and expression of the proteins mediating cell adhesion were imaged using a confocal microscope. SEM-EDS analysis demonstrated the formation of HA on the ALD-HA surfaces. The relative cell attachment was significantly higher (p < .05) on the ALD-HA compared to the NC surface after 1 and 3 d of cell culture. No significant difference was found in integrin α6 or β4 expression. The microscope evaluation showed significantly increased cell spreading with peripheral HD expression on ALD-HA compared to the NC surfaces (p = .0001). Moreover, laminin γ2 expression was significantly higher on the ALD-HA than on the NC surfaces (p < .001). Compared to the NC Ti surface, the ALD-HA coating has favorable effects on HGK proliferation, growth, and cell spreading. This indicates that the ALD-HA coating has good potential for improving mucosal attachment on implant surfaces.

The Combination of Super-Active Platelet Lysate and Acellular Amniotic Membrane Enhances Endometrial Receptivity, While Simultaneously Facilitating Endometrial Repair in Rats.

To investigate the combined effects of super-active platelet lysate (sPL) and acellular amniotic membrane (AAM) in promoting endometrial repair and enhancing endometrial receptivity in rats. The characteristics of sPL-AAM were examined through scanning electron microscopy, contact angle tester, and release experiments. We aimed to establish a rat model for endometrial injury. We divided sixty-four rats into four groups: the Injury group (Control group), the AAM group, the sPL group, and the sPL-AAM group. Our study compared the endometrial thickness, gland count, and fibrotic area recovery in rats at 6 days and 18 days post-treatment. Immunohistochemistry was utilized to assess the expressions of CD34 and ANG. Additionally, we used ELISA to detect the levels of IL-6 and TNF-α, while Western Blot was employed to compare the expressions of CK19, Integrin β3, and TGF-β1. One month after the treatment, we evaluated and compared the pregnancy recovery among the groups. Compared to the Injury group, the sPL-AAM group demonstrated enhanced endometrial regeneration in rats at both 6 days and 18 days post-treatment, resulting in a favorable pregnancy outcome. This was achieved by promoting angiogenesis, suppressing the inflammatory response, and reducing fibrosis. The observed effects were superior to those of the sPL group alone. While sPL, when administered alone, showed some degree of endometrial restoration at 6 days post-treatment, its efficacy was diminished at 18 days post-treatment. The impact of AAM alone appeared inconspicuous compared to the injury group. This suggests that sPL serves as the primary agent in facilitating endometrial repair, while AAM functions as a carrier to extend the duration of sPL's effectiveness. sPL-AAM can release effective cytokines, repair endometrial damage in rats, enhance endometrial receptivity, and ultimately improve pregnancy outcomes.

A novel solvent-extruded tacrolimus-eluting suture for attenuated inflammation and scarring in skin repair

This study aimed to design an absorbable suture that locally delivers the immunosuppressive agent, tacrolimus (FK506), to attenuate scar tissue formation by modulating inflammation. As the suture degrades, it releases FK506 directly into the repair site. The poly (l-lactide-co-caprolactone) (PLLA-PCL) polymer and 0.2 % wt FK506 were co-extruded using a solvent extrusion technique to generate the drug-eluting sutures. The properties of the generated sutures were assessed regarding FK506 release in vitro, wound closure in an in vivo murine model, murine skin histology for structural and inflammatory markers, and mechanical strength of both sutures and healed murine skin. The generated suture consistently released FK506 at ≤10 ng/day rates. Following annealing, the sutures retained 60 % of their anticipated tensile strength, exhibiting enhanced ductility. The histological examination and in vivo murine study indicated that wounds treated with FK506-eluting PLLA-PCL sutures produced a thinner epidermal layer, enhanced integrin β4 expression, increased keratinocyte presence, attenuated inflammation, and reduced scarring, demonstrating healed tissue improvements compared with those treated with the placebo, poly (glycolic-co-caprolactone) (PGCL), sutures. Mechanical evaluations of healed tissue indicated that drug-PLLA-PCL sutures did not reduce the mechanical strength of the skin compared to placebo PGCL sutures. The FK506-eluting PLLA-PCL sutures show promising results in advancing wound healing by offering targeted drug delivery. This innovative method can improve wound healing and provide a streamlined approach to scar management. Continued research, optimization, and broad-scale studies are needed to refine the manufacturing process and ensure that the properties of the suture meet clinical requirements.

Innovative 3D-Printed Titanium Specimens Favor a Modulation of Inflammation in Dental Pulp Stem Cells During Liposome-Triggered Mineralization.

developing customized titanium specimens, with innovative surfaces, is a suitable strategy to overcome implant failure. Additionally, a faster and efficient osteogenic commitment assists tissue regeneration. To investigate the interplay between inflammation and differentiation upon implantation, Dental Pulp Stem Cells (DPSCs) were cultured on 3D-printed titanium owning an internal open cell form, administering osteogenic factors by a liposomal formulation (LipoMix) compared to traditional delivery of differentiation medium (DM). osteogenic differentiation was evaluated by western blot, by measuring β1 integrin expression, and by and real-time RT-PCR, by measuring SP7 and Collagen I gene expression; while.angiogenesis was characterized by measuring VEGF secretion levels. Matrix mineralization was assessed by means of Alizarin Red Staining, cell adhesion and inflammation responses through western blot, enzymatic and ELISA assays evaluating Nrf2 expression, catalase activity and Prostaglandin E2 secretion, respectively. LipoMix enhances cell proliferation and adhesion, as revealed by increased integrin β1 expression. Mineralized matrix deposition, SP7 gene expression, Collagen I release and Alkaline Phosphatase activity appear increased in LipoMix condition. Additionally, the redox-sensitive transcription factor Nrf2 is overexpressed at the earliest experimental times, triggering the catalase activity. data reported confirm that internal topography and post-production treatments on titanium surfaces dynamically and positively condition the DPSC progress towards the osteogenic phenotype, moreover, the combination with LipoMix fastens the positive modulation of inflammation under osteogenic conditions. Therefore, the development of customized surfaces along with the administration of differentiating factors enclosed in a liposomal delivery system, could represent a promising and innovative tool in regenerative dentistry.

ROCK Inhibitor Enhances Neurite Outgrowth In Vitro and Corneal Sensory Nerve Reinnervation In Vivo.

The intraepithelial corneal nerves are essential to corneal health. Rho kinase or ROCK inhibitors (RIs) have been reported to play a role in neuron survival after injury. Here we assess integrin and extracellular matrix expression in primary mouse neurons and determine whether treating cells with RI impacts neurite outgrowth in vitro and reinnervation after trephine and debridement injury in mice in vivo. Cocultures of human corneal limbal epithelial cells and E11.5 mouse trigeminal neurons and neurons alone were grown on glass coverslips. High-resolution imaging was performed to localize integrins and laminin on neurons and to determine whether RI impacts neurite outgrowth in vitro and in vivo after both 1.5-mm trephine and 1.5-mm debridement injuries. Several integrin α (α3, α6, αv) chains as well as β4 integrin are expressed on neuron axons and growth cones in cocultures. RI treatment of isolated neurons, cocultures, and in conditioned media increases neurite outgrowth. In vivo, RI positively impacts sensory nerve reinnervation after trephine and debridement injury. These studies are the first to demonstrate expression of β4 integrin on trigeminal sensory neurons and preferential adhesion of neurons to the laminin-enriched matrices found in footprints deposited by human corneal limbal epithelial cells. In addition, we also document for the first time the positive impact of RI on neurite outgrowth in vitro and reinnervation in vivo.

Insights into the metastatic bone marrow niche gained from fibronectin and β1 integrin transgenic mice

Tumor cells can migrate from a primary cancer and form metastases by localizing to niches within other organs including the bone marrow, where tumor cells may exploit the hematopoietic stem cell niche. The precise composition of the premetastatic and the hematopoietic niches and the degree of overlap between them remain elusive. Because the extracellular matrix protein fibronectin is expressed in the pre-metastatic lung microenvironment, we evaluated the implications of its loss, as well as those of loss of its primary receptor subunit, β1 integrin, in various bone marrow cell types both in breast cancer bone metastasis and hematopoiesis.Using eight transgenic mouse models, we established that fibronectin production by osterix-expressing marrow cells, or β1 integrin expression (on vav, mx, or leptin receptor expressing cells), affects MDA-MB-231 breast cancer cell numbers in the bone marrow. Additionally, we identified stromal subpopulations that modulate transmigration through blood vessel walls. Not the number of tumor cells, but rather the changes in the microenvironment dictated whether the tumor progresses. Furthermore, hematopoiesis, particularly myelopoiesis, was affected in some of the models showing changes in tumor homing.In conclusion, there is partial overlap between the pre-metastatic and the hematopoietic niches in the bone marrow. Moreover, we have delineated a cascade starting with fibronectin secreted by pre-osteoblastic cells, which potentially acts on β1 integrin in specific stromal cell subsets, thereby inhibiting the formation of new breast cancer lesions in the bone marrow. This work therefore sheds light on the role of various stromal cell subpopulations that influence tumor behavior and affect hematopoiesis.

Expression of interleukin-8 and integrin β3 predicts prognosis of patients with hepatocellular carcinoma after hepatectomy.

As important components in the tumor microenvironment, interleukin-8 (IL-8) and integrin β3 play a key role in the progression and metastasis of hepatocellular carcinoma (HCC). This study aimed to determine the expression of IL-8 and integrin β3 and their prognostic value in patients with HCC after hepatectomy. We investigated the expression of IL-8 and integrin β3, their clinical significance, as well as their correlation in the cancer tissue of 130 patients with HCC using immunohistochemistry. The prognostic value of IL-8 and integrin β3 was investigated through the follow-up of patients with HCC after hepatectomy. In HCC, IL-8 expression had a positive correlation with integrin β3 expression. Increased expressions of IL-8 and integrin β3 were indicators of tumor progression and poor prognosis in patients with HCC after hepatectomy. IL-8 positive specimens exhibited a higher proportion of macrovascular invasion, larger tumor size, poor differentiation, and advanced tumor-node-metastasis (TNM) stage (P < .05, respectively). Integrin β3 positive group exhibited a higher proportion of TNM III-staged tumors (P < .05). The results indicated that macrovascular invasion, advanced TNM stage, and integrin β3 expression were independent unfavorable prognostic factors in HCC after hepatectomy. Integrin β3 expression was proved to be an independent unfavorable prognostic factor in HCC after hepatectomy. Targeting integrin β3 might be a potential therapeutic approach in preventing tumor progression in HCC.

Pleiotrophin Activates cMet- and mTORC1-Dependent Protein Synthesis through PTPRZ1-The Role of ανβ3 Integrin.

Pleiotrophin (PTN) is a secreted factor that regulates endothelial cell migration through protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) and αvβ3 integrin. Genetic deletion of Ptprz1 results in enhanced endothelial cell proliferation and migration, due to the decreased expression of β3 integrin and the subsequent, enhanced cMet phosphorylation. In the present study, we investigated the effect of PTN and PTPRZ1 on activating the mTORC1 kinase and protein synthesis and identified part of the implicated signaling pathway in endothelial cells. PTN or genetic deletion of Ptprz1 activates protein synthesis in a mTORC1-dependent manner, as shown by the enhanced phosphorylation of the mTORC1-downstream targets ribosomal protein S6 kinase 1 (SK61) and 4E-binding protein 1 (4EBP1) and the upregulation of HIF-1α. The cMet tyrosine kinase inhibitor crizotinib abolishes the stimulatory effects of PTN or PTPRZ1 deletion on mTORC1 activation and protein synthesis, suggesting that mTORC1 activation is downstream of cMet. The mTORC1 inhibitor rapamycin abolishes the stimulatory effect of PTN or PTPRZ1 deletion on endothelial cell migration, suggesting that mTORC1 is involved in the PTN/PTPRZ1-dependent cell migration. The αvβ3 integrin blocking antibody LM609 and the peptide PTN112-136, both known to bind to ανβ3 and inhibit PTN-induced endothelial cell migration, increase cMet phosphorylation and activate mTORC1, suggesting that cMet and mTORC1 activation are required but are not sufficient to stimulate cell migration. Overall, our data highlight novel aspects of the signaling pathway downstream of the PTN/PTPRZ1 axis that regulates endothelial cell functions.

Cyclosporine A improves the binding of mouse embryos to fibronectin.

The binding of integrin αvβ3 with endometrial fibronectin (FN) promotes the migration of preimplantation embryos in mice. We have previously shown that cyclosporine A (CsA) improves the adhesion and invasion of mouse preimplantation embryos. In this study, we evaluated the roles of calcium ions and downstream signaling factors in the binding of integrin αvβ3 to FN. Female Institute of Cancer Research (ICR) mice were superovulated and mated, and two-cell embryos were harvested from the oviducts and cultured to the blastocyst stage The adhesion and stretching growth of hatched embryos in laminin-coated dishes were evaluated, and integrinβ3 expression was determined using qPCR. Blastocytes were cultured with 0 or 1 cyclosporine A (CsA) and the attachment of embryonic integrin αvβ3 to FN120 was observed using a fluorescent bead. To further determine the mechanism, the cells were also incubated with calcium ions and protein kinase C and calmodulin antagonists. The binding of integrin αvβ3 to FN120 was examined via confocal laser scanning microscopy. The adhesion and stretching growth of peri-implantation embryos were greater and integrinβ3 expression was higher in the 1 μM CsA group than in the 0 μM CsA group (p < 0.05). When incubated with calcium ions and protein kinase C and calmodulin antagonists, the ability of peri-implantation embryos to bind to FN decreased; CsA treatment promoted this binding. This study revealed that CsA up - regulates integrinβ3 expression in peri - implantation embryos and promotes binding to FN via calcium ions, and protein kinase C, and calmodulin. These findings provide evidence supporting the beneficial effect of CsA on the peri - implantation embryo adhesion.

Elevated MMP-9, Survivin, TGB1 and Downregulated Tissue Inhibitor of TIMP-1, Caspase-3 Activities are Independent of the Low Levels miR-183 in Endometriosis.

This study aimed to measure the correlation between miR-183 and gene expression that regulates apoptosis and adhesion mechanism that may be linked to the pathogenesis of endometriosis. Forty-four subjects, including 22 control subjects, participated in this study. We collected ectopic endometriosis and endometrial samples. For the control, the sample was taken from endometrial tissue through pipelle biopsy. RNA was extracted from all tissues using RNA mini kit, and the expression was assessed using quantitative-real time PCR. Relative mRNA and miRNA expression were presented using the formula of the Livak method. The data were statistically analyzed using GraphPad Prism 8. The expression of Caspase-3, Survivin, Integrin β1 (ITGB1), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) (adhesion- and apoptosis-related gene) were calculated using the relative expression method. We found significant differences in Caspase-3, Survivin, ITGB1, MMP-9, and TIMP-1 expression between ectopic endometriosis tissues of women with endometriosis compared to healthy endometrium. MMP-9, Survivin, and ITGB1 was significantly increased in the endometriosis group, while Caspase-3, TIMP-1, and miR-183 were significantly reduced in the endometriosis group. No correlation was found between the expression level of miR-183 and Caspase3, Survivin, ITGB1, and Cadherin in both tissue types. Despite the difference in expression levels of miR-183 and associated adhesion- and apoptosis-related genes, there was no significant association between miR-183 with specific adhesion and apoptosis genes in endometriosis tissue.

YKL40/Integrin β4 Axis Induced by the Interaction between Cancer Cells and Tumor-Associated Macrophages Is Involved in the Progression of High-Grade Serous Ovarian Carcinoma.

Macrophages in the tumor microenvironment, termed tumor-associated macrophages (TAMs), promote the progression of various cancer types. However, many mechanisms related to tumor-stromal interactions in epithelial ovarian cancer (EOC) progression remain unclear. High-grade serous ovarian carcinoma (HGSOC) is the most malignant EOC subtype. Herein, immunohistochemistry was performed on 65 HGSOC tissue samples, revealing that patients with a higher infiltration of CD68+, CD163+, and CD204+ macrophages had a poorer prognosis. We subsequently established an indirect co-culture system between macrophages and EOC cells, including HGSOC cells. The co-cultured macrophages showed increased expression of the TAM markers CD163 and CD204, and the co-cultured EOC cells exhibited enhanced proliferation, migration, and invasion. Cytokine array analysis revealed higher YKL40 secretion in the indirect co-culture system. The addition of YKL40 increased proliferation, migration, and invasion via extracellular signal-regulated kinase (Erk) signaling in EOC cells. The knockdown of integrin β4, one of the YKL40 receptors, suppressed YKL40-induced proliferation, migration, and invasion, as well as Erk phosphorylation in some EOC cells. Database analysis showed that high-level expression of YKL40 and integrin β4 correlated with a poor prognosis in patients with serous ovarian carcinoma. Therefore, the YKL40/integrin β4 axis may play a role in ovarian cancer progression.

Kindlin-2 regulates the oncogenic activities of integrins and TGF-β in triple-negative breast cancer progression and metastasis

Kindlin-2, an adapter protein, is dysregulated in various human cancers, including triple-negative breast cancer (TNBC), where it drives tumor progression and metastasis by influencing several cancer hallmarks. One well-established role of Kindlin-2 involves the regulation of integrin signaling, achieved by directly binding to the cytoplasmic tail of the integrin β subunit. In this study, we present novel insights into Kindlin-2’s involvement in stabilizing the β1-Integrin:TGF-β type 1 receptor (TβRI) complexes, acting as a physical bridge that links β1-Integrin to TβRI. Loss of Kindlin-2 results in the degradation of this protein complex, leading to the inhibition of downstream oncogenic pathways. We used a diverse range of in vitro assays, including CRISPR/Cas9 gene editing, cell migration, 3D-tumorsphere formation and invasion, solid binding, co-immunoprecipitation, cell adhesion and spreading assays, as well as western blot and flow cytometry analyses, utilizing MDA-MB-231 and 4T1 TNBC cell lines. Additionally, preclinical in vivo mouse models of TNBC tumor progression and metastasis were employed to substantiate our findings. Our studies established the direct interaction between Kindlin-2 and β1-Integrin and between Kindlin-2 and TβRI. Disruption of these interactions, via CRISPR/Cas9-mediated knockout of Kindlin-2, led to the degradation of β1-Integrin and TβRI, resulting in the inhibition of oncogenic pathways downstream of both proteins, subsequently hindering tumor growth and metastasis. Treatment of Kindlin-2-deficient cells with the proteasome inhibitor MG-132 restored the expression of both β1-Integrin and TβRI. Furthermore, the rescue of Kindlin-2 expression reinstated their oncogenic activities in vitro and in vivo, while Kindlin-2 lacking domains involved in the interaction of Kindlin-2 with β1-Integrin or TβRI did not. This study identifies a novel function of Kindlin-2 in stabilizing the β1-Integrin:TβRI complexes and regulating their downstream oncogenic signaling. The translational implications of these findings are substantial, potentially unveiling new therapeutically targeted pathways crucial for the treatment of TNBC tumors.

Short-Term Exposure to Foodborne Xenoestrogens Affects Breast Cancer Cell Morphology and Motility Relevant for Metastatic Behavior In Vitro.

Breast cancer is highly susceptible to metastasis formation. During the time of disease progression, tumor pathophysiology can be impacted by endogenous factors, like hormonal status, as well as by environmental exposures, such as those related to diet and lifestyle. New lines of evidence point toward a potential role for foodborne endocrine disruptive chemicals in this respect; however, mechanistic understanding remains limited. At the molecular level, crucial steps toward metastasis formation include cell structural changes, alteration of adhesion, and reorganization of cytoskeletal proteins involved in motility. Hence, this study investigates the potential of dietary xenoestrogens to impact selected aspects of breast cancer cell mechanotransduction. Taking the onset of the metastatic cascade as a model, experiments focused on cell-matrix adhesion, single-cell migration, and adaptation of cell morphology. Dietary mycoestrogens alternariol (AOH, 1 μM) and α-zearalenol (α-ZEL, 10 nM), soy isoflavone genistein (GEN, 1 μM), and food packaging plasticizer bisphenol A (BPA, 10 nM) were applied as single compounds or in mixtures. Pursuing the hypothesis that endocrine active molecules could affect cell functions beyond the estrogen receptor-dependent cascade, experiments were performed comparing the MCF-7 cell line to the triple negative breast cancer cells MDA MB-231. Indeed, the four compounds functionally affected the motility and the adhesion of both cell types. These responses were coherent with rearrangements of the actin cytoskeleton and with the modulation of the expression of integrin β1 and cathepsin D. Mechanistically, molecular dynamics simulations confirmed a potential interaction with fragments of the α1 and β1 integrin subunits. In sum, dietary xenoestrogens proved effective in modifying the motility and adhesion of breast cancer cells, as predictive end points for metastatic behavior in vitro. These effects were measurable after short incubation times (1 or 8 h) and contribute to shed novel light on the activity of compounds with hormonal mimicry potential in breast cancer progression.

Integrin profle of circulating tumour cells in breast cancer patients

Background. Integrins, as adhesion molecules, play a key role in the interaction of cells with the basal membrane and intercellular matrix. Numerous studies demonstrate evidence of increased expression of integrins on tumor cells in different types of cancer. Thus, β3 and αV integrins are associated with stem-like features of tumor cells, and β4 integrin as α6β4 heterodimer provides anchorage-independent survival of malignant mammary epithelial cells. However, all the described functions of integrins have been investigated exclusively on primary tumor cells. The functional significance and expression pattern of integrins on circulating tumor cells (CTCs) remains unclear. The aim of the study was to evaluate the β3, β4 and αvβ5 integrin expression on CTCs and its association with molecular subtype, stage and lymph node metastasis in breast cancer patients Material and Methods. The study included 22 patients with T1–4N0–3M0 invasive ductal breast carcinoma. Venous blood was taken from patients without neoadjuvant chemotherapy (group 1) and after neoadjuvant chemotherapy (group 2) in the volume of 12 ml into vacuum tubes with EDTA. The expression of CTC integrins including stemness features CD44/CD24, CD133 and ALDH1, and epithelial-mesenchymal transition (EMT) (N-cadherin) was evaluated by flow cytometry. Results. CTCs with β3+β4-αvβ5- and β3-β4+αvβ5+ phenotypes and stemness properties were associated with larger tumor size (T4) in breast cancer patients. The β3 integrin expression was associated with more aggressive molecular subtypes of breast cancer. Administration of neoadjuvant chemotherapy did not affect the expression pattern of β3, β4 and αvβ5 integrins in CTCs. Conclusion. In breast cancer, most CTCs expressed β3, β4 and αvβ5 integrins despite the lack of attachment to the basal membrane and intercellular matrix. The expression of the above integrins on CTCs was associated with breast cancer molecular subtype, stage and lymph node metastasis, and therefore its evaluation can be considered as one of the objectives of liquid biopsy study.

Abstract 64: Smooth Muscle Cullin-3 Regulates the Renal Baroreceptor Mechanism: a Link Between CUL3 and Integrin β1

Cullin-3 (CUL3) is a critical component of the CUL3-Ring-Ligase (CRL) ubiquitin ligase complex. CUL3 mutants in smooth muscle cells (SMCs) cause vascular dysfunction, arterial stiffness, and severe hypertension (HTN). We hypothesized that conditional deletion of CUL3 in SMCs (S-CUL3KO) led to HTN via 1) a renin-angiotensin system (RAS)-dependent mechanism, and 2) impaired renal baroreceptor mechanism regulating renin expression. CUL3 Flox mice were bred to mice carrying tamoxifen-inducible CRE-recombinase under a smooth muscle promoter (ISM-CRE, control). S-CUL3KO mice exhibited augmented systolic blood pressure (SBP) (ISM-CRE: 124±1 vs. S-CUL3KO: 167±3 mmHg, p&lt;0.05) 3-weeks post tamoxifen. Once HTN was established we used an angiotensin-converting enzyme inhibitor (captopril, 10 mg/kg/day in drinking water) for 1 week to reverse HTN. We observed a greater depressor effect in S-CUL3KO (ΔSBP -49±3 mmHg) compared to ISM-CRE (ΔSBP -33±1 mmHg, p&lt;0.05). A similar effect was identified following angiotensin II type I receptor blocker (ARB, candesartan, 100 mg/kg/day in drinking water) treatment (ΔSBP, ISM-CRE: -27±2 vs. S-CUL3KO: -37±2, p&lt;0.05). We prevented HTN in S-CUL3KO by administering ARB before tamoxifen injection (SBP 120±5 mmHg). Mesenteric arteries exhibited augmented Ang-II induced vasoconstriction, which was prevented with ARB, suggesting that HTN in S-CUL3KO is RAS-dependent and AT 1 R-mediated. Despite severe HTN, S-CUL3KO did not suppress renin mRNA expression in kidneys. We hypothesize that S-CUL3KO exhibits a defective renal baroreceptor mechanism causing impaired suppression of renin expression. We propose that CUL3 participates in the degradation of integrin β1, the key mechanosensory of the renal baroreceptor, via Rab-mediated trafficking and lysosomal fusion. Supporting this, HEK293 cells lacking CUL3 exhibited lower integrin β1 protein expression (0.51±0.08 vs. 0.09±0.01 normalized RFU, p&lt;0.05) concomitant with increased Rab5 and Rab7 expression (3.6±0.3 vs. 1.9±0.1 and 0.95±0.12 vs. 0.37±0.04 normalized RFU). S-CUL3KO demonstrated severely impaired morphological distribution of integrin β1 protein in the juxtaglomerular apparatus. In conclusion, our findings support the hypothesis that 1) CUL3 regulates RAS via the renal baroreceptor, and 2) Rab proteins regulating integrin β1 expression are potential targets for the CRL3 pathway. Understanding CUL3 target proteins might contribute to the development of new strategies to treat HTN.

A Pro-Inflammatory Stimulus versus Extensive Passaging of DITNC1 Astrocyte Cultures as Models to Study Astrogliosis.

Astrogliosis is a process by which astrocytes, when exposed to inflammation, exhibit hypertrophy, motility, and elevated expression of reactivity markers such as Glial Fibrillar Acidic Protein, Vimentin, and Connexin43. Since 1999, our laboratory in Chile has been studying molecular signaling pathways associated with "gliosis" and has reported that reactive astrocytes upregulate Syndecan 4 and αVβ3 Integrin, which are receptors for the neuronal glycoprotein Thy-1. Thy-1 engagement stimulates adhesion and migration of reactive astrocytes and induces neurons to retract neurites, thus hindering neuronal network repair. Reportedly, we have used DITNC1 astrocytes and neuron-like CAD cells to study signaling mechanisms activated by the Syndecan 4-αVβ3 Integrin/Thy-1 interaction. Importantly, the sole overexpression of β3 Integrin in non-reactive astrocytes turns them into reactive cells. In vitro, extensive passaging is a simile for "aging", and aged fibroblasts have shown β3 Integrin upregulation. However, it is not known if astrocytes upregulate β3 Integrin after successive cell passages. Here, we hypothesized that astrocytes undergoing long-term passaging increase β3 Integrin expression levels and behave as reactive astrocytes without needing pro-inflammatory stimuli. We used DITNC1 cells with different passage numbers to study reactivity markers using immunoblots, immunofluorescence, and astrocyte adhesion/migration assays. We also evaluated β3 Integrin levels by immunoblot and flow cytometry, as well as the neurotoxic effects of reactive astrocytes. Serial cell passaging mimicked the effects of inflammatory stimuli, inducing astrocyte reactivity. Indeed, in response to Thy-1, β3 Integrin levels, as well as cell adhesion and migration, gradually increased with multiple passages. Importantly, these long-lived astrocytes expressed and secreted factors that inhibited neurite outgrowth and caused neuronal death, just like reactive astrocytes in culture. Therefore, we describe two DITNC1 cell types: a non-reactive type that can be activated with Tumor Necrosis Factor (TNF) and another one that exhibits reactive astrocyte features even in the absence of TNF treatment. Our results emphasize the importance of passage numbers in cell behavior. Likewise, we compare the pro-inflammatory stimulus versus long-term in-plate passaging of cell cultures and introduce them as astrocyte models to study the reactivity process.

Integrin αV Inhibition by GMI, a Ganoderma Microsporum Immunomodulatory Protein, Abolish Stemness and Migration in EGFR-Mutated Lung Cancer Cells Resistant to Osimertinib.

Integrins, the receptors of the extracellular matrix, are critical in the proliferation and metastasis of cancer cells. GMI, a Ganoderma microsporum immunomodulatory protein, possesses anticancer and antivirus abilities. The object of this study is to investigate the role of GMI in the integrins signaling pathway in lung cancer cells that harbor the EGFR L858R/T790M double mutation and osimertinib-resistance. Liquid chromatography-mass spectrometry and western blot assay were used to investigate the effect of GMI on inhibiting the protein expressions of integrins in H1975 cells. The migration ability and xenograft tumor growth of H1975 were suppressed by GMI. To elucidate the role of the integrin family in lung cancer resistant to osimertinib (AZD-9291, Tagrisso), H1975 cells were used to establish the osimertinib-resistant cells, named H1975/TR cells. The expressions of Integrin αV and stemness markers were much higher in H1975/TR cells than in H1975 cells. GMI suppressed cell viability, tumor spheroid growth, and the expressions of integrin αV and β1 in H1975/TR cells. Furthermore, GMI suppressed the expressions of stemness markers and formation of tumor spheres via blocking integrin αV signaling cascade. This is the first study to reveal the novel function of GMI in constraining cancer stem cells and migration by abolishing the integrin αV-related signaling pathway in EGFR-mutated and osimertinib-resistant lung cancer cells.

Effects of Bushen Huoxue on integrin β3 and integrin β5 in the placental tissue of mice with repeated implantation failure caused by phospholipid antibodies.

This study aimed to investigate the effects of the Kidney-Tonifying and Blood-Activating Formula on combating the downregulation of integrin β3 and integrin β5 in mouse placental tissue induced by phospholipid antibodies. This study aimed to investigate the effects of kidney-tonifying and blood-activating formulations on combating the downregulation of integrin β3 and integrin β5 in mouse placental tissue induced by phospholipid antibodies. Mice in the phospholipid antibody group and phospholipid antibody + kidney-tonifying and blood-activating formula group underwent repeated implantation experiments, and the expression of integrin β3 and integrin β5 in placental tissue was observed. The effects of the kidney-tonifying and blood-activating formula on mouse placental tissue were evaluated through biochemical index tests, histopathological observations, and immunohistochemical staining. After intervention with the kidney-tonifying and blood-activating formula, the expression of integrin β3 and integrin β5 in placental tissue was notably upregulated, and placental structure was restored. Kidney-Tonifying and Blood-Activating Formula significantly improved abnormal biochemical indices and exerted a remarkable protective effect on placental tissue pathology. The kidney-tonifying and blood-activating formula effectively counteracted the downregulation of integrin β3 and integrin β5 in mouse placental tissue induced by phospholipid antibodies and alleviated placental tissue pathology through structural improvement and protection. Therefore, kidney-tonifying and blood-activating formulas may serve as potential therapeutic agents for recurrent implantation failure, offering new insights and approaches for clinical treatment.

Abstract We122: Suppression of defender against cell death 1 (Dad1) induces cardiomyocyte death by regulating cell adhesion proteins.

Introduction: Suppression of cardiomyocyte loss is considered a promising strategy for the prevention of the onset of heart failure (HF). Previously, defender against cell death 1 ( Dad1 ) was identified as a cytoprotective gene. Dad1 forms a complex with staurosporine and temperature sensitive 3A (Stt3A), a catalytic subunit of oligosaccharyltransferase (OST) complex which is responsible for N-glycosylation. However, the function of Dad1 in cardiomyocytes remains unknown. Hypothesis: The disruption of cell-extracellular matrix interactions results in cell death, known as anoikis. Because various cell adhesion proteins are N-glycosylated, we hypothesized that Dad1 suppressed anoikis by regulating N-glycosylation of cell adhesion proteins in cardiomyocytes. Methods: Neonatal rat cardiomyocytes were cultured and the expression of Dad1 or Stt3A was knocked down using siRNA. The protein expression was assessed with immunoblot analysis, and cell viability was evaluated using a CellTiter-Blue assay kit. Results: The suppression of Dad1 using siRNAs reduced cardiomyocyte viability ( p &lt;0.01, n=4). Interestingly, suppression of Dad1 impaired the N-glycosylation of integrin β1 and decreased the expression of mature integrin β1 ( p &lt;0.01, n=3). These changes inactivated integrin-mediated signal transduction through dephosphorylation of focal adhesion kinase ( p &lt;0.01, n=5). In addition, enhanced cell-extracellular matrix interactions by using adhesamine rescued the cardiomyocyte death by Dad1 knockdown ( p &lt;0.01, n=4). Next, we pursued the relationship between Dad1 and Stt3A. Dad1 knockdown decreased the expression of Stt3A ( p &lt;0.01, n=6). Suppression of Stt3A induced cardiomyocyte death accompanied by the changes of cell adhesion proteins ( p &lt;0.01, n=4). Finally, double knockdown of Dad1 and Stt3A did not induce a further reduction in cell viability compared with the knockdown of only Dad1 ( p &lt;0.05, n=4), suggesting that cardiomyocyte death by Dad1 knockdown was dependent on Stt3A. Conclusion: Dad1 is required for the stabilization of Stt3A and suppresses cardiomyocyte anoikis by regulating N-glycosylation of cell adhesion proteins in an OST-dependent manner. Dad1-mediated cardiomyocyte survival could be a therapeutic target against HF.