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Approximately two-thirds of hepatocellular carcinoma (HCC) is considered a "cold tumor" characterized by few tumor-infiltrating T cells and an abundance of immunosuppressive cells. Cilengitide, an integrin αvβ3 inhibitor, has failed in clinical trials as a potential anticancer drug. This failure implies that integrin αvβ3 may play an important role in immune cells. However, the expression and potential role of integrin αvβ3 in T cells of HCC patients remain unknown. Here, we established two HCC models and found that cilengitide had a dual effect on the HCC microenvironment by exerting both antitumor effect and immunosuppressive effect on T cells. This may partly explain the failure of cilengitide in clinical trials. In clinical specimens, HCC-infiltrating T cells exhibited deficient expression and activation of integrin β3, which was associated with poor T-cell infiltration into tumors. Additionally, integrin β3 functioned as a positive immunomodulatory molecule to facilitate T-cell infiltration and T helper 1-type immune response in vitro. Furthermore, T cells and platelet-derived microparticles (PMPs) co-culture assay revealed that PMPs adoptively transferred integrin β3 to T cells and positively regulated T cell immune response. This process was mediated by clathrin-dependent endocytosis and macropinocytosis. Our data demonstrate that integrin β3 deficiency on HCC-infiltrating T cells may be involved in shaping the immunosuppressive tumor microenvironment. PMPs transfer integrin β3 to T cells and positively regulate T cell immune response, which may provide a new insight into immune therapy of HCC. [ABSTRACT FROM AUTHOR]

Thyroid carcinoma (TC) is the most common endocrine neoplasia, with its incidence increasing in the last 40 years worldwide. The determination of genetic and/or protein markers for thyroid carcinoma could increase diagnostic precision. Accumulated evidence shows that Protein kinase C alpha (PKCα) contributes to tumorigenesis and therapy resistance in cancer. However, the role of PKCα in TC remains poorly studied. Our group and others have demonstrated that PKCs can mediate the proliferative effects of thyroid hormones (THs) through their membrane receptor, the integrin αvβ3, in several cancer types. We found that PKCα is overexpressed in TC cell lines, and it also appeared as the predominant expressed isoform in public databases of TC patients. PKCα-depleted cells significantly reduced THs-induced proliferation, mediated by the integrin αvβ3 receptor, through AKT and Erk activation. In databases of TC patients, higher PKCα expression was associated with lower overall survival. Further analyses showed a positive correlation between PKCα and genes from the MAPK and PI3K-Akt pathways. Finally, immunohistochemical analysis showed abnormal upregulation of PKCα in human thyroid tumors. Our findings establish a potential role for PKCα in the control of hormone-induced proliferation that can be explored as a therapeutic and/or diagnostic target for TC. [ABSTRACT FROM AUTHOR]

Despite significant progress in combining cancer immunotherapy with chemotherapy to treat triple negative breast cancer (TNBC), challenges persist due to target depletion and tumor heterogeneity, especially in metastasis. Chemotherapy lacks precise targeting abilities, and targeted therapy is inadequate in addressing the diverse heterogeneity of tumors. To address these challenges, we introduce RGDEVD-DOX as a tumor-specific immunogenic agent, namely TPD1, which targets integrin αvβ3 and gets continuously activated by apoptosis. TPD1 facilitates the caspase-3-mediated in situ amplification that results in tumor-specific accumulation of doxorubicin. This local concentration of doxorubicin induces immunogenic cell death and promotes the recruitment of immune cells to the tumor site. Notably, the tumor-targeting capabilities of TPD1 help bypass the systemic immunotoxicity of doxorubicin. Consequently, this alters the tumor microenvironment, converting it into a 'hot' tumor that is more susceptible to immune checkpoint inhibition. We demonstrated the anti-metastatic and anti-cancer efficacy of this treatment using various xenograft and metastatic models. This study underscores the high potential of caspase-3 cleavable peptide-drug conjugates to be used in conjunction with anti-cancer immunotherapies. Metastatic TNBC targeting strategy of TPD1 utilizing focused immune stimulation and caspase-3 mediated amplification cycle. [Display omitted] • Demonstrated effective induction of immunogenic cell death and enhanced immunogenicity in tumors. • Achieved effective targeted drug delivery utilizing the caspase-3 mediated activating cycle. • Successfully targets both primary tumors and metastasis in diverse mice TNBC models. • Shows synergistic anticancer efficacy when combined with anti-PD1 treatments. • Exhibits minimal immunotoxic effects compared to doxorubicin, ensuring safer combination therapies. [ABSTRACT FROM AUTHOR]

Cerebral ischemia–reperfusion injury significantly contributes to global morbidity and mortality. Loganin is a natural product with various neuroprotective effects; however, it lacks targeted specificity for particular cells or receptors, which may result in reduced therapeutic efficacy and an increased risk of side effects. To address the limitations of loganin, we developed LA-1, a novel compound incorporating an Arg-Gly-Asp (RGD) peptide to target integrin receptor αvβ3, enhancing brain-targeting efficacy. LA-1 exhibited optimal nanoscale properties, significantly improved cell viability, reduced ROS production, and enhanced survival rates in vitro. In vivo, LA-1 decreased infarct sizes, improved neurological function, and reduced oxidative stress and neuroinflammation. Proteomic analysis showed LA-1 modulates PI3K/Akt and Nrf2/HO-1 pathways, providing targeted neuroprotection. These findings suggest LA-1's potential for clinical applications in treating cerebral ischemia–reperfusion injury. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of repetitive transcranial magnetic stimulation (rTMS) as a nonpharmacological approach to treating neuropathic pain (NP), a major challenge in clinical research. Conducted on male Sprague-Dawley rats with NP induced through chronic constriction injury of the sciatic nerve, the research assessed pain behaviors and the impact of rTMS on molecular interactions within the amygdala. Through a comprehensive analysis involving Mechanical Withdrawal Threshold (MWT), Thermal Withdrawal Latency (TWL), RNA transcriptome sequencing, RT-qPCR, Western blotting, immunofluorescence staining, and Co-Immunoprecipitation (Co-IP), the study focused on the expression and interaction of integrin αvβ3 and its receptor P2X7R. Findings reveal that rTMS significantly influences the expression of integrin αvβ3 in NP models, suggesting an inhibition of the NP-associated NLRP3 inflammatory pathway through the disruption of integrin αvβ3-P2X7R interactions. These outcomes highlight the potential of rTMS in alleviating NP by targeting molecular interactions within the amygdala, offering a promising therapeutic avenue for managing NP. [ABSTRACT FROM AUTHOR]

Aim: 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. Methods: 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 μM 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. Results: 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]

Xuefeng Hou,1– 4,&ast; Qi Chen,1,&ast; Ying Fang,5 Li Zhang,1 Shuoheng Huang,1 Minjie Xu,1 Yaning Ren,1 Zhansen Shi,1 Yan Wei,1 Lihua Li1– 4 1School of Pharmacy, Wannan Medical College, Wuhu, Anhui Province, People’s Republic of China; 2Anhui Provincial Engineering Laboratory for Screening and Re-Evaluation of Active Compounds of Herbal Medicines in Southern Anhui, Wannan Medical College, Wuhu, Anhui Province, People’s Republic of China; 3Anhui Provincial Engineering Research Center for Polysaccharide Drugs, Wannan Medical College, Wuhu, Anhui Province, People’s Republic of China; 4Drug Research and Development Center, Wannan Medical College, Wuhu, Anhui Province, People’s Republic of China; 5School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yan Wei; Lihua Li, School of Pharmacy, Wannan Medical College, No. 22, West Wenchang Road, Wuhu, 241002, People’s Republic of China, Email yanwei@wnmc.edu.cn; llh05530226@126.comBackground: Breast cancer presents significant challenges due to the limited effectiveness of available treatments and the high likelihood of recurrence. iRGD possesses both RGD sequence and C-terminal sequence and has dual functions of targeting and membrane penetration. iRGD-modified nanocarriers can enhance drug targeting of tumor vascular endothelial cells and penetration of new microvessels, increasing drug concentration in tumor tissues.Methods: The amidation reaction was carried out between SiO2/AuNCs and iRGD/PTX, yielding a conjugated drug delivery system (SiO2/AuNCs-iRGD/PTX, SAIP@NPs). The assessment encompassed the characterization of the morphology, particle size distribution, physicochemical properties, in vitro release profile, cytotoxicity, and cellular uptake of SAIP@NPs. The tumor targeting and anti-tumor efficacy of SAIP@NPs were assessed using a small animal in vivo imaging system and a tumor-bearing nude mice model, respectively. The tumor targeting and anti-tumor efficacy of SAIP@NPs were assessed utilizing a small animal in vivo imaging system and an in situ nude mice breast cancer xenograft model, respectively.Results: The prepared SAIP@NPs exhibited decent stability and a certain slow-release effect in phosphate buffer (PBS, pH 7.4). In vitro studies had shown that, due to the dual functions of transmembrane and targeting of iRGD peptide, SAIP@NPs exhibited strong binding to integrin αvβ 3, which was highly expressed on the membrane of MDA-MB-231 cells, improving the uptake capacity of tumor cells, inhibiting the rapid growth of tumor cells, and promoting tumor cell apoptosis. The results of animal experiments further proved that SAIP@NPs had longer residence time in tumor sites, stronger anti-tumor effect, and no obvious toxicity to major organs of experimental animals.Conclusion: The engineered SAIP@NPs exhibited superior functionalities including efficient membrane permeability, precise tumor targeting, and imaging, thereby significantly augmenting the therapeutic efficacy against breast cancer with a favorable safety profile. Keywords: silicon dioxide nanoparticles, gold nanoclusters, iRGD penetrating peptide, integrin αvβ 3, tumor targeting, breast cancer

Purpose: Glaucoma, one of the leading causes of irreversible blindness, is a common progressive optic neuropathy characterised by visual field defects and structural changes to the optic nerve head (ONH). There is extracellular matrix (ECM) accumulation and fibrosis of the lamina cribrosa (LC) in the ONH, and consequently increased tissue stiffness of the LC connective tissue. Integrins are cell surface proteins that provide the key molecular link connecting cells to the ECM and serve as bidirectional sensors transmitting signals between cells and their environment to promote cell adhesion, proliferation, and remodelling of the ECM. Here, we investigated the expression of αVβ3 integrin in glaucoma LC cell, and its effect on stiffness-induced ECM gene transcription and cellular proliferation rate in normal (NLC) and glaucoma (GLC) LC cells, by down-regulating αVβ3 integrin expression using cilengitide (a known potent αVβ3 and αVβ5 inhibitor) and β3 integrin siRNA knockdown. Methods: GLC cells were compared to age-matched controls NLC to determine differential expression levels of αVβ3 integrin, ECM genes (Col1A1, α-SMA, fibronectin, vitronectin), and proliferation rates. The effects of αVβ3 integrin blockade (with cilengitide) and silencing (with a pool of four predesigned αVβ3 integrin siRNAs) on ECM gene expression and proliferation rates were evaluated using both reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting in the human NLC cells cultured on soft (4 kPa) and stiff (100 kPa) substrate and in GLC cells grown on standard plastic plates. Results: αVβ3 integrin gene and protein expression were enhanced (p < 0.05) in GLC cells as compared to NLC. Both cilengitide and siRNA significantly reduced αVβ3 expression in GLC. When NLC were grown in the stiff substrate, cilengitide and siRNA also significantly reduced the increased expression in αVβ3, ECM components, and proliferation rate. Conclusions: Here, we provide evidence of cilengitide- and siRNA-mediated silencing of αVβ3 integrin expression, and inhibition of ECM synthesis in LC cells. Therefore, αVβ3 integrin may be a promising target for the development of novel anti-fibrotic therapies for treating the LC cupping of the ONH in glaucoma. [ABSTRACT FROM AUTHOR]

Purpose: The advancement of heterodimeric tracers, renowned for their high sensitivity, marks a significant trend in the development of radiotracers for cancer diagnosis. Our prior work on [68Ga]Ga-HX01, a heterodimeric tracer targeting CD13 and integrin αvβ3, led to its approval for phase I clinical trials by the China National Medical Production Administration (NMPA). However, its fast clearance and limited tumor retention pose challenges for broader clinical application in cancer treatment. This study aims to develop a new radiopharmaceutical with increased tumor uptake and prolonged retention, rendering it a potential therapeutic candidate. Methods: New albumin binder-conjugated compounds were synthesized based on the structure of HX01. In vitro and in vivo evaluation of these new compounds were performed after labelling with 68Ga. Small-animal PET/CT imaging were conducted at different time points at 0.5–6 h post injection (p.i.) using BxPC-3 xenograft mice models. The one with the best imaging performance was further radiolabeled with 177Lu for small-animal SPECT/CT and ex vivo biodistribution investigation. Results: We have synthesized novel albumin binder-conjugated compounds, building upon the structure of HX01. When radiolabeled with 68Ga, all compounds demonstrated improved pharmacokinetics (PK). Small-animal PET/CT studies revealed that these new albumin binder-conjugated compounds, particularly [68Ga]Ga-L6, exhibited significantly enhanced tumor accumulation and retention compared with [68Ga]Ga-L0 without an albumin binder. [68Ga]Ga-L6 outperformed [68Ga]Ga-L7, a compound developed using a previously reported albumin binder. Furthermore, [177Lu]Lu-L6 demonstrated rapid clearance from normal tissues, high tumor uptake, and prolonged retention in small-animal SPECT/CT and biodistribution studies, positioning it as an ideal candidate for radiotherapeutic applications. Conclusion: A new integrin αvβ3 and CD13 targeting compound was screened out. This compound bears a novel albumin binder and exhibits increased tumor uptake and prolonged tumor retention in BxPC-3 tumors and low background in normal organs, making it a perfect candidate for radiotherapy when radiolabeled with 177Lu. [ABSTRACT FROM AUTHOR]

Apoptosis is induced in cancer cells and tumor xenografts by the thyroid hormone analogue tetraiodothyroacetic acid (tetrac) or chemically modified forms of tetrac. The effect is initiated at a hormone receptor on the extracellular domain of plasma membrane integrin αvβ3. The tumor response to tetrac includes 80% reduction in size of glioblastoma xenograft in two weeks of treatment, with absence of residual apoptotic cancer cell debris; this is consistent with efferocytosis. The molecular basis for efferocytosis linked to tetrac is incompletely understood, but several factors are proposed to play roles. Tetrac-based anticancer agents are pro-apoptotic by multiple intrinsic and extrinsic pathways and differential effects on specific gene expression, e.g., downregulation of the X-linked inhibitor of apoptosis (XIAP) gene and upregulation of pro-apoptotic chemokine gene, CXCL10. Tetrac also enhances transcription of chemokine CXCR4, which is relevant to macrophage function. Tetrac may locally control the conformation of phagocyte plasma membrane integrin αvβ3; this is a cell surface recognition system for apoptotic debris that contains phagocytosis signals. How tetrac may facilitate the catabolism of the engulfed apoptotic cell debris requires additional investigation. [ABSTRACT FROM AUTHOR]

The burgeoning field of cancer theranostics has witnessed advancements through the development of targeted molecular agents, particularly peptides. These agents exploit the overexpression or mutations of specific receptors, such as the Epidermal Growth Factor receptor (EGFR) and αVβ3 integrin, which are pivotal in tumor growth, angiogenesis, and metastasis. Despite the extensive research into and promising outcomes associated with antibody-based therapies, peptides offer a compelling alternative due to their smaller size, ease of modification, and rapid bioavailability, factors which potentially enhance tumor penetration and reduce systemic toxicity. However, the application of peptides in clinical settings has challenges. Their lower binding affinity and rapid clearance from the bloodstream compared to antibodies often limit their therapeutic efficacy and diagnostic accuracy. This overview sets the stage for a comprehensive review of the current research landscape as it relates to EGFR- and integrin αVβ3-targeting peptides. We aim to delve into their synthesis, radiolabeling techniques, and preclinical and clinical evaluations, highlighting their potential and limitations in cancer theranostics. This review not only synthesizes the extant literature to outline the advancements in peptide-based agents targeting EGFR and integrin αVβ3 but also identifies critical gaps that could inform future research directions. By addressing these gaps, we contribute to the broader discourse on enhancing the diagnostic precision and therapeutic outcomes of cancer treatments. [ABSTRACT FROM AUTHOR]

Endothelial programmed death‐ligand 1 (PD‐L1) expression is higher in tumors than in normal tissues. Also, tumoral vasculatures tend to be leakier than normal vessels leading to a higher trans‐endothelial or transmural fluid flow. However, it is not clear whether such elevated transmural flow can control endothelial PD‐L1 expression. Here, a new microfluidic device is developed to investigate the relationship between transmural flow and PD‐L1 expression in microvascular networks (MVNs). After treating the MVNs with transmural flow for 24 h, the expression of PD‐L1 in endothelial cells is upregulated. Additionally, CD8 T cell activation by phytohemagglutinin (PHA) is suppressed when cultured in the MVNs pre‐conditioned with transmural flow. Moreover, transmural flow is able to further increase PD‐L1 expression in the vessels formed in the tumor microenvironment. Finally, by utilizing blocking antibodies and knock‐out assays, it is found that transmural flow‐driven PD‐L1 upregulation is controlled by integrin αVβ3. Overall, this study provides a new biophysical explanation for high PD‐L1 expression in tumoral vasculatures. [ABSTRACT FROM AUTHOR]

Simple Summary: Yuan et al. present a strategy to modulate tumor immunity by simultaneously depleting CAFs and tumor angiogenic vessels using a rationally designed protein that induces integrin αvβ3-expressing cell apoptosis. The study offers a unique opportunity for the enhancement of cancer immunotherapies, especially for patients with a tumor of dense stroma and high angiogenesis. Fibrotic stroma and angiogenic tumor vessels play an important role in modulating tumor immunity. We previously reported a rationally designed protein (ProAgio) that targets integrin αvβ3 at a novel site. ProAgio induces the apoptosis of cells that express high levels of the integrin. Both activated cancer-associated fibroblasts (CAFs) and angiogenic endothelial cells (aECs) in tumors express high levels of integrin αvβ3. ProAgio simultaneously and specifically induces apoptosis in CAFs and aECs in tumors. We provide evidence here that the depletion of CAFs and the elimination of leaky tumor angiogenic vessels by ProAgio alter tumor immunity. ProAgio reduces CD4+ Treg and Myeloid-derived suppressor cells (MDSCs), increases CD8+ T-cells, and increases the M1/M2 macrophage ratio in the tumor. The depletion of dense fibrotic stroma (CAFs) by ProAgio decreases the Programmed Death Ligand 1 (PDL-1) levels in the stroma areas surrounding the tumors, and thus strongly increases the delivery of anti-PDL-1 antibody to the target cancer cells. The impact of ProAgio on tumor immunity provides strong synergistical effects of checkpoint inhibitors on lung cancer treatment. [ABSTRACT FROM AUTHOR]

Nonalcoholic steatohepatitis (NASH) and alcoholic hepatitis (AH) affect a large part of the general population worldwide. Dysregulation of lipid metabolism and alcohol toxicity drive disease progression by the activation of hepatic stellate cells and the capillarization of liver sinusoidal endothelial cells. Collagen deposition, along with sinusoidal remodeling, alters sinusoid structure, resulting in hepatic inflammation, portal hypertension, liver failure, and other complications. Efforts were made to develop treatments for NASH and AH. However, the success of such treatments is limited and unpredictable. We report a strategy for NASH and AH treatment involving the induction of integrin αvβ3-mediated cell apoptosis using a rationally designed protein (ProAgio). Integrin αvβ3 is highly expressed in activated hepatic stellate cells (αHSCs), the angiogenic endothelium, and capillarized liver sinusoidal endothelial cells (caLSECs). ProAgio induces the apoptosis of these disease-driving cells, therefore decreasing collagen fibril, reversing sinusoid remodeling, and reducing immune cell infiltration. The reversal of sinusoid remodeling reduces the expression of leukocyte adhesion molecules on LSECs, thus decreasing leukocyte infiltration/activation in the diseased liver. Our studies present a novel and effective approach for NASH and AH treatment. [ABSTRACT FROM AUTHOR]

Approximately two-thirds of hepatocellular carcinoma (HCC) is considered a “cold tumor” characterized by few tumor-infiltrating T cells and an abundance of immunosuppressive cells. Cilengitide, an integrin αvβ3 inhibitor, has failed in clinical trials as a potential anticancer drug. This failure implies that integrin αvβ3 may play an important role in immune cells. However, the expression and potential role of integrin αvβ3 in T cells of HCC patients remain unknown. Here, we established two HCC models and found that cilengitide had a dual effect on the HCC microenvironment by exerting both antitumor effect and immunosuppressive effect on T cells. This may partly explain the failure of cilengitide in clinical trials. In clinical specimens, HCC-infiltrating T cells exhibited deficient expression and activation of integrin β3, which was associated with poor T-cell infiltration into tumors. Additionally, integrin β3 functioned as a positive immunomodulatory molecule to facilitate T-cell infiltration and T helper 1-type immune response in vitro. Furthermore, T cells and platelet-derived microparticles (PMPs) co-culture assay revealed that PMPs adoptively transferred integrin β3 to T cells and positively regulated T cell immune response. This process was mediated by clathrin-dependent endocytosis and macropinocytosis. Our data demonstrate that integrin β3 deficiency on HCC-infiltrating T cells may be involved in shaping the immunosuppressive tumor microenvironment. PMPs transfer integrin β3 to T cells and positively regulate T cell immune response, which may provide a new insight into immune therapy of HCC.

Abstract Background Ossification of the posterior longitudinal ligament (OPLL), an emerging heterotopic ossification disease, causes spinal cord compression, resulting in motor and sensory dysfunction. The etiology of OPLL remains unclear but may involve integrin αVβ3 regulating the process of osteogenesis and angiogenesis. In this study, we focused on the role of integrin αVβ3 in OPLL and explored the underlying mechanism by which the c(RGDyk) peptide acts as a potent and selective integrin αVβ3 inhibitor to inhibit osteogenesis and angiogenesis in OPLL. Methods OPLL or control ligament samples were collected in surgery. For OPLL samples, RNA-sequencing results revealed activation of the integrin family, particularly integrin αVβ3. Integrin αVβ3 expression was detected by qPCR, Western blotting, and immunohistochemical analysis. Fluorescence microscopy was used to observe the targeted inhibition of integrin αVβ3 by the c(RGDyk) peptide on ligaments fibroblasts (LFs) derived from patients with OPLL and endothelial cells (ECs). The effect of c(RGDyk) peptide on the ossification of pathogenic LFs was detected using qPCR, Western blotting. Alkaline phosphatase staining or alizarin red staining were used to test the osteogenic capability. The effect of the c(RGDyk) peptide on angiogenesis was determined by EC migration and tube formation assays. The effects of the c(RGDyk) peptide on heterotopic bone formation were evaluated by micro-CT, histological, immunohistochemical, and immunofluorescence analysis in vivo. Results The results indicated that after being treated with c(RGDyk), the osteogenic differentiation of LFs was significantly decreased. Moreover, the c(RGDyk) peptide inhibited the migration of ECs and thus prevented the nutritional support required for osteogenesis. Furthermore, the c(RGDyk) peptide inhibited ectopic bone formation in mice. Mechanistic analysis revealed that c(RGDyk) peptide could inhibit osteogenesis and angiogenesis in OPLL by targeting integrin αVβ3 and regulating the FAK/ERK pathway. Conclusions Therefore, the integrin αVβ3 appears to be an emerging therapeutic target for OPLL, and the c(RGDyk) peptide has dual inhibitory effects that may be valuable for the new therapeutic strategy of OPLL.

Integrin receptor αvβ3 and gastrin-releasing peptide receptor (GRPR) expression of tumors could be detected using PET imaging with radiolabeled Arg-Gly-Asp (RGD) and the antagonistic bombesin analog RM26, respectively. The purpose of this study was to investigate the dual receptor-targeting property of the heterodimer RGD-RM26-03 (denoted as LNC1015), demonstrate the tumor diagnostic value of [68Ga]Ga-LNC1015 in preclinical experiments, and evaluate its preliminary clinical feasibility. Methods: LNC1015 was designed and synthesized by linking cyclic RGD and the RM26 peptide. Preclinical pharmacokinetics were detected in a PC3 xenograft model using microPET and biodistribution studies. The clinical feasibility of [68Ga]Ga-LNC1015 PET/CT was performed in patients with breast cancer, and the results were compared with those of 18F-fluorodeoxyglucose (FDG). Results: [68Ga]Ga-LNC1015 had good stability in saline for at least 2 h, and favorable binding affinity and specificity were demonstrated in vitro and in vivo. The tumor uptake and retention of [68Ga]Ga-LNC1015 during PET imaging were improved compared with its monomeric counterparts [68Ga]Ga-RGD and [68Ga]Ga-RM26 at all the time points examined. In our initial clinical studies, the tumor uptake and tumor-to-background ratio (TBR) of primary and metastatic lesions in [68Ga]Ga-LNC1015 PET/CT were significantly higher than those in [18F]FDG PET/CT, resulting in high lesion detection rate and tumor delineation. Conclusion: The dual targeting radiotracer [68Ga]Ga-LNC1015 showed significantly improved tumor uptake and retention, as well as lower liver uptake than [68Ga]Ga-RGD and [68Ga]Ga-RM26 monomer. The first-in-human study showed high TBRs in patients, suggesting favorable pharmacokinetics and high clinical feasibility for PET/CT imaging of cancer. [ABSTRACT FROM AUTHOR]

Purpose: Several studies have demonstrated the advantages of heterodimers over their corresponding monomers due to the multivalency effect. This effect leads to an increased number of effective targeted receptors and, consequently, improved tumor uptake. Fibroblast activation protein (FAP) and integrin αvβ3 are found to be overexpressed in different components of the tumor microenvironment. In our pursuit of enhancing tumor uptake and retention, we designed and developed a novel peptidic heterodimer that synergistically targets both FAP and integrin αvβ3. Methods: FAP-RGD was synthesized from FAP-2286 and c(RGDfK) through a multi-step organic synthesis. The dual receptor binding property of 68Ga-FAP-RGD was investigated by cell uptake and competitive binding assays. Preclinical pharmacokinetics were determined in HT1080-FAP and U87MG tumor models using micro-positron emission tomography/computed tomography (micro-PET/CT) and biodistribution studies. The antitumor efficacy of 177Lu-FAP-RGD was assessed in U87MG tumor models. The radiation exposure and clinical diagnostic performance of 68 Ga-FAP-RGD were evaluated in healthy volunteers and cancer patients. Results: Bi-specific radiotracer 68Ga-FAP-RGD exhibited high binding affinity for both FAP and integrin αvβ3. In comparison to 68Ga-FAP-2286 and 68Ga-RGDfK, 68Ga-FAP-RGD displayed enhanced tumor uptake and longer tumor retention time in preclinical models. 177Lu-FAP-RGD could efficiently suppress the growth of U87MG tumor in vivo when applied at an activity of 18.5 and 29.6 MBq. The effective dose of 68Ga-FAP-RGD was 1.06 × 10−2 mSv/MBq. 68Ga-FAP-RGD demonstrated low background activity and stable accumulation in most neoplastic lesions up to 3 h. Conclusion: Taking the advantages of multivalency effect, the bi-specific radiotracer 68Ga-FAP-RGD showed superior tumor uptake and retention compared to its corresponding monomers. Preclinical studies with 68Ga- or 177Lu-labeled FAP-RGD showed favorable image contrast and effective antitumor responses. Despite the excellent performance of 68Ga-FAP-RGD in clinical diagnosis, experimental efforts are currently underway to optimize the structure of FAP-RGD to increase its potential for clinical application in endoradiotherapy. [ABSTRACT FROM AUTHOR]

Due to the heterogeneity of tumors, strategies to improve the effectiveness of dual-targeting tracers in tumor diagnostics have been intensively practiced. In this study, the radiolabeled [18F]AlF-NOTA-FAPI-RGD (denoted as [18F]AlF-LNC1007), a dual-targeting heterodimer tracer targeting both fibroblast activation protein (FAP) and integrin αvβ3 to enhance specific tumor uptake and retention, was synthesized and evaluated. The tracer was compared with [68Ga]Ga-LNC1007 in preclinical and clinical settings. Methods: The preparation of [18F]AlF- and 68Ga-labeled FAPI-RGD was carried out with an optimized protocol. The stability was tested in PBS and fetal bovine serum (FBS). Cellular uptake and in vivo distribution of the two products were compared and carried out on the U87MG cell line and its xenograft model. The safety and dosimetry of [18F]AlF-LNC1007 PET/CT scan were evaluated in six patients with malignant tumors. Results: Two radiolabeling protocols of [18F]AlF-/[68Ga]Ga-LNC1007 were developed and optimized to give a high yield of tracers with good stability. In vivo microPET images showed that the two tracers exhibited comparable pharmacokinetic characteristics, with high tumor uptake and prolonged tumor retention. In vivo distribution data showed that the target-to-non-target ratios of [18F]AlF-LNC1007 were similar to[68Ga]Ga-LNC1007. A total of six patients underwent [18F]AlF-LNC1007 PET/CT evaluation while two had head-to-head [18F]FDG PET/CT scans. The total body effective dose was 9.94E-03 mSv/MBq. The biodistribution curve showed optimal normal organ uptake with high tumor uptake and long retention of up to 3h p.i., and notably, the tumor-to-background ratio increased over time. Conclusion: We successfully prepared an [18F]AlF-LNC1007 dual-targeting PET probe with comparable performances as [68Ga]Ga-LNC1007. With prolonged tumor retention and tumor specificity, it produced good imaging quality in preclinical and clinical translational studies, indicating that [18F]AlF-LNC1007 is a promising non-invasive tracer for detecting tumors expressing FAP and/or integrin avβ3, with the prospect of clinical implementation. [ABSTRACT FROM AUTHOR]

Purpose: Several studies have demonstrated the advantages of heterodimers over their corresponding monomers due to the multivalency effect. This effect leads to an increased number of effective targeted receptors and, consequently, improved tumor uptake. Fibroblast activation protein (FAP) and integrin αvβ3 are found to be overexpressed in different components of the tumor microenvironment. In our pursuit of enhancing tumor uptake and retention, we designed and developed a novel peptidic heterodimer that synergistically targets both FAP and integrin αvβ3. Methods: FAP-RGD was synthesized from FAP-2286 and c(RGDfK) through a multi-step organic synthesis. The dual receptor binding property of 68Ga-FAP-RGD was investigated by cell uptake and competitive binding assays. Preclinical pharmacokinetics were determined in HT1080-FAP and U87MG tumor models using micro-positron emission tomography/computed tomography (micro-PET/CT) and biodistribution studies. The antitumor efficacy of 177Lu-FAP-RGD was assessed in U87MG tumor models. The radiation exposure and clinical diagnostic performance of 68 Ga-FAP-RGD were evaluated in healthy volunteers and cancer patients. Results: Bi-specific radiotracer 68Ga-FAP-RGD exhibited high binding affinity for both FAP and integrin αvβ3. In comparison to 68Ga-FAP-2286 and 68Ga-RGDfK, 68Ga-FAP-RGD displayed enhanced tumor uptake and longer tumor retention time in preclinical models. 177Lu-FAP-RGD could efficiently suppress the growth of U87MG tumor in vivo when applied at an activity of 18.5 and 29.6 MBq. The effective dose of 68Ga-FAP-RGD was 1.06 × 10−2 mSv/MBq. 68Ga-FAP-RGD demonstrated low background activity and stable accumulation in most neoplastic lesions up to 3 h. Conclusion: Taking the advantages of multivalency effect, the bi-specific radiotracer 68Ga-FAP-RGD showed superior tumor uptake and retention compared to its corresponding monomers. Preclinical studies with 68Ga- or 177Lu-labeled FAP-RGD showed favorable image contrast and effective antitumor responses. Despite the excellent performance of 68Ga-FAP-RGD in clinical diagnosis, experimental efforts are currently underway to optimize the structure of FAP-RGD to increase its potential for clinical application in endoradiotherapy. [ABSTRACT FROM AUTHOR]

Background: Ossification of the posterior longitudinal ligament (OPLL), an emerging heterotopic ossification disease, causes spinal cord compression, resulting in motor and sensory dysfunction. The etiology of OPLL remains unclear but may involve integrin αVβ3 regulating the process of osteogenesis and angiogenesis. In this study, we focused on the role of integrin αVβ3 in OPLL and explored the underlying mechanism by which the c(RGDyk) peptide acts as a potent and selective integrin αVβ3 inhibitor to inhibit osteogenesis and angiogenesis in OPLL. Methods: OPLL or control ligament samples were collected in surgery. For OPLL samples, RNA-sequencing results revealed activation of the integrin family, particularly integrin αVβ3. Integrin αVβ3 expression was detected by qPCR, Western blotting, and immunohistochemical analysis. Fluorescence microscopy was used to observe the targeted inhibition of integrin αVβ3 by the c(RGDyk) peptide on ligaments fibroblasts (LFs) derived from patients with OPLL and endothelial cells (ECs). The effect of c(RGDyk) peptide on the ossification of pathogenic LFs was detected using qPCR, Western blotting. Alkaline phosphatase staining or alizarin red staining were used to test the osteogenic capability. The effect of the c(RGDyk) peptide on angiogenesis was determined by EC migration and tube formation assays. The effects of the c(RGDyk) peptide on heterotopic bone formation were evaluated by micro-CT, histological, immunohistochemical, and immunofluorescence analysis in vivo. Results: The results indicated that after being treated with c(RGDyk), the osteogenic differentiation of LFs was significantly decreased. Moreover, the c(RGDyk) peptide inhibited the migration of ECs and thus prevented the nutritional support required for osteogenesis. Furthermore, the c(RGDyk) peptide inhibited ectopic bone formation in mice. Mechanistic analysis revealed that c(RGDyk) peptide could inhibit osteogenesis and angiogenesis in OPLL by targeting integrin αVβ3 and regulating the FAK/ERK pathway. Conclusions: Therefore, the integrin αVβ3 appears to be an emerging therapeutic target for OPLL, and the c(RGDyk) peptide has dual inhibitory effects that may be valuable for the new therapeutic strategy of OPLL. [ABSTRACT FROM AUTHOR]

Cell migration interacting with continuously changing microenvironment, is one of the most essential cellular functions, participating in embryonic development, wound repair, immune response, and cancer metastasis. The migration process is finely tuned by integrin‐mediated binding to ligand molecules. Although numerous biochemical pathways orchestrating cell adhesion and motility are identified, how subcellular forces between the cell and extracellular matrix regulate intracellular signaling for cell migration remains unclear. Here, it is showed that a molecular binding force across integrin subunits determines directional migration by regulating tension‐dependent focal contact formation and focal adhesion kinase phosphorylation. Molecular binding strength between integrin αvβ3 and fibronectin is precisely manipulated by developing molecular tension probes that control the mechanical tolerance applied to cell‐substrate interfaces. This data reveals that integrin‐mediated molecular binding force reduction suppresses cell spreading and focal adhesion formation, attenuating the focal adhesion kinase (FAK) phosphorylation that regulates the persistence of cell migration. These results further demonstrate that manipulating subcellular binding forces at the molecular level can recapitulate differential cell migration in response to changes of substrate rigidity that determines the physical condition of extracellular microenvironment. Novel insights is provided into the subcellular mechanics behind global mechanical adaptation of the cell to surrounding tissue environments featuring distinct biophysical signatures. [ABSTRACT FROM AUTHOR]

Abstract Endothelial programmed death‐ligand 1 (PD‐L1) expression is higher in tumors than in normal tissues. Also, tumoral vasculatures tend to be leakier than normal vessels leading to a higher trans‐endothelial or transmural fluid flow. However, it is not clear whether such elevated transmural flow can control endothelial PD‐L1 expression. Here, a new microfluidic device is developed to investigate the relationship between transmural flow and PD‐L1 expression in microvascular networks (MVNs). After treating the MVNs with transmural flow for 24 h, the expression of PD‐L1 in endothelial cells is upregulated. Additionally, CD8 T cell activation by phytohemagglutinin (PHA) is suppressed when cultured in the MVNs pre‐conditioned with transmural flow. Moreover, transmural flow is able to further increase PD‐L1 expression in the vessels formed in the tumor microenvironment. Finally, by utilizing blocking antibodies and knock‐out assays, it is found that transmural flow‐driven PD‐L1 upregulation is controlled by integrin αVβ3. Overall, this study provides a new biophysical explanation for high PD‐L1 expression in tumoral vasculatures.

Progesterone (P4) plays a pivotal role in regulating the cancer progression of various types, including breast cancer, primarily through its interaction with the P4 receptor (PR). In PR-negative breast cancer cells, P4 appears to function in mediating cancer progression, such as cell growth. However, the mechanisms underlying the roles of P4 in PR-negative breast cancer cells remain incompletely understood. This study aimed to investigate the effects of P4 on cell proliferation, gene expression, and signal transduction in PR-negative MDA-MB-231 breast cancer cells. P4-activated genes, associated with proliferation in breast cancer cells, exhibit a stimulating effect on cell growth in PR-negative MDA-MB-231 cells, while demonstrating an inhibitory impact in PR-positive MCF-7 cells. The use of arginine-glycine-aspartate (RGD) peptide successfully blocked P4-induced extracellular signal-regulated kinase 1/2 (ERK1/2) activation, aligning with computational models of P4 binding to integrin αvβ3. Disrupting integrin αvβ3 binding with RGD peptide or anti-integrin αvβ3 antibody altered P4-induced expression of proliferative genes and modified P4-induced cell growth in breast cancer cells. In conclusion, integrin αvβ3 appears to mediate P4-induced ERK1/2 signal pathway to regulate proliferation via alteration of proliferation-related gene expression in PR-negative breast cancer cells.

Cerebral ischemia–reperfusion injury significantly contributes to global morbidity and mortality. Loganin is a natural product with various neuroprotective effects; however, it lacks targeted specificity for particular cells or receptors, which may result in reduced therapeutic efficacy and an increased risk of side effects. To address the limitations of loganin, we developed LA-1, a novel compound incorporating an Arg-Gly-Asp (RGD) peptide to target integrin receptor αvβ3, enhancing brain-targeting efficacy. LA-1 exhibited optimal nanoscale properties, significantly improved cell viability, reduced ROS production, and enhanced survival rates in vitro. In vivo, LA-1 decreased infarct sizes, improved neurological function, and reduced oxidative stress and neuroinflammation. Proteomic analysis showed LA-1 modulates PI3K/Akt and Nrf2/HO-1 pathways, providing targeted neuroprotection. These findings suggest LA-1’s potential for clinical applications in treating cerebral ischemia–reperfusion injury.

Purpose: To compare the potential efficiency of [68Ga]Ga-LNC1007 with 2-[18F]FDG/[68Ga]Ga-PSMA PET/CT for detecting renal cell carcinoma (RCC) and to explore parameters derived from [68Ga]Ga-LNC1007 PET/CT for discriminating pathological characteristics in RCC. Methods: Twenty-five RCC patients confirmed by pathology were enrolled in this prospective study. The maximum standardized uptake value (SUVmax), mean SUV (SUVmean), gross tumor volume (GTV) and total lesion-tracer (TL-tracer) of lesions were calculated from the corresponding PET/CT images. Pathological characteristics included World Health Organization/International Society of Urological Pathology (WHO/ISUP) grade and adverse pathological features (tumor necrosis or sarcomatoid or rhabdoid feature). Results: [68Ga]Ga-LNC1007 PET/CT showed a higher detection rate for primary lesions than 2-[18F]FDG and [68Ga]Ga-PSMA (LNC1007 vs. FDG: 13/17 vs. 4/17, P = 0.005; LNC1007 vs. PSMA: 9/11 vs. 6/11, P = 0.361). [68Ga]Ga-LNC1007 PET/CT showed higher SUVmax (6.6 vs. 3.7, P = 0.005), SUVmean (4.1 vs. 2.3, P = 0.001) and TBR (2.6 vs. 1.7, P = 0.011) compared with 2-[18F]FDG PET/CT, and it also showed higher TBR (2.9 vs. 0.5, P = 0.003), TBR-delay (2.8 vs. 0.3, P = 0.003), GTV (84.1 vs. 42.9, P = 0.003) and TL-tracer (442.7 vs. 235.8, P = 0.008) compared with [68Ga]Ga-PSMA PET/CT. SUVmax and TBR derived from [68Ga]Ga-LNC1007 PET/CT could effectively differentiate WHO/ISUP grade (3–4 vs. 1–2) and adverse pathological features (positive vs. negative) (SUVmax: AUC 0.81, P = 0.04; AUC 0.80, P = 0.033; TBR: AUC 0.84, P = 0.026; AUC 0.85, P = 0.014). The SUVmax was positively correlated with the FAP expression, integrin αvβ3 expression and the total expression of FAP and integrin αvβ3 (r = 0.577, P = 0.006, r = 0.701, P < 0.001, and r = 0.702, P < 0.001, respectively). Conclusion: [68Ga]Ga-LNC1007 is a promising tracer for RCC imaging and can effectively identify aggressive pathological characteristics of RCC. [ABSTRACT FROM AUTHOR]

Fluorescent probes are valuable tools to visualize non‐catalytic proteins in live cells. Currently, the majority of imaging reagents for non‐catalytic proteins are based on "always‐on" fluorophores and the use of these reagents usually necessitate a wash step to remove unbounded fluorophores before microscope imaging. Herein, we report the use of arylamino‐substituted rhodamine as an activatable fluorophore for the imaging of non‐catalytic protein in live cells. We have shown the induction of an arylamino to structurally rigid rhodamine could significantly reduce the fluorescent emission in aqueous medium but the ligand‐directed binding of this molecule to protein receptor could effective restrict its intramolecular motion and thus lead to enhancement in fluorescence intensity at 590 nm over 30‐fold. With fluorescent probes based on this fluorophore, we could visualize integrin αvβ3 and azido‐functionalized glycans in living cells with high contrast in a wash‐free manner. [ABSTRACT FROM AUTHOR]

Abstract Cell migration interacting with continuously changing microenvironment, is one of the most essential cellular functions, participating in embryonic development, wound repair, immune response, and cancer metastasis. The migration process is finely tuned by integrin‐mediated binding to ligand molecules. Although numerous biochemical pathways orchestrating cell adhesion and motility are identified, how subcellular forces between the cell and extracellular matrix regulate intracellular signaling for cell migration remains unclear. Here, it is showed that a molecular binding force across integrin subunits determines directional migration by regulating tension‐dependent focal contact formation and focal adhesion kinase phosphorylation. Molecular binding strength between integrin αvβ3 and fibronectin is precisely manipulated by developing molecular tension probes that control the mechanical tolerance applied to cell‐substrate interfaces. This data reveals that integrin‐mediated molecular binding force reduction suppresses cell spreading and focal adhesion formation, attenuating the focal adhesion kinase (FAK) phosphorylation that regulates the persistence of cell migration. These results further demonstrate that manipulating subcellular binding forces at the molecular level can recapitulate differential cell migration in response to changes of substrate rigidity that determines the physical condition of extracellular microenvironment. Novel insights is provided into the subcellular mechanics behind global mechanical adaptation of the cell to surrounding tissue environments featuring distinct biophysical signatures.

Abstract Background Integrins are closely related to mechanical conduction and play a crucial role in the osteogenesis of human mesenchymal stem cells. Here we wondered whether tensile stress could influence cell differentiation through integrin αVβ3. Methods We inhibited the function of integrin αVβ3 of human mesenchymal stem cells by treating with c(RGDyk). Using cytochalasin D and verteporfin to inhibit polymerization of microfilament and function of nuclear Yes-associated protein (YAP), respectively. For each application, mesenchymal stem cells were loaded by cyclic tensile stress of 10% at 0.5 Hz for 2 h daily. Mesenchymal stem cells were harvested on day 7 post-treatment. Western blotting and quantitative RT-PCR were used to detect the expression of alkaline phosphatase (ALP), RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining detected vinculin, actin filaments, and YAP nuclear localization. Results Cyclic tensile stress could increase the expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation led to rearrangement of actin filaments and downregulated the expression of ALP, RUNX2 and promoted YAP nuclear localization. When microfilament polymerization was inhibited, ALP, RUNX2, and nuclear YAP nuclear localization decreased. Inhibition of YAP nuclear localization could reduce the expression of ALP and RUNX2. Conclusions Cyclic tensile stress promotes early osteogenesis of human mesenchymal stem cells via the integrin αVβ3-actin filaments axis. YAP nuclear localization participates in this process of human mesenchymal stem cells. Video Abstract

Purpose: Glaucoma, one of the leading causes of irreversible blindness, is a common progressive optic neuropathy characterised by visual field defects and structural changes to the optic nerve head (ONH). There is extracellular matrix (ECM) accumulation and fibrosis of the lamina cribrosa (LC) in the ONH, and consequently increased tissue stiffness of the LC connective tissue. Integrins are cell surface proteins that provide the key molecular link connecting cells to the ECM and serve as bidirectional sensors transmitting signals between cells and their environment to promote cell adhesion, proliferation, and remodelling of the ECM. Here, we investigated the expression of αVβ3 integrin in glaucoma LC cell, and its effect on stiffness-induced ECM gene transcription and cellular proliferation rate in normal (NLC) and glaucoma (GLC) LC cells, by down-regulating αVβ3 integrin expression using cilengitide (a known potent αVβ3 and αVβ5 inhibitor) and β3 integrin siRNA knockdown. Methods: GLC cells were compared to age-matched controls NLC to determine differential expression levels of αVβ3 integrin, ECM genes (Col1A1, α-SMA, fibronectin, vitronectin), and proliferation rates. The effects of αVβ3 integrin blockade (with cilengitide) and silencing (with a pool of four predesigned αVβ3 integrin siRNAs) on ECM gene expression and proliferation rates were evaluated using both reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting in the human NLC cells cultured on soft (4 kPa) and stiff (100 kPa) substrate and in GLC cells grown on standard plastic plates. Results: αVβ3 integrin gene and protein expression were enhanced (p < 0.05) in GLC cells as compared to NLC. Both cilengitide and siRNA significantly reduced αVβ3 expression in GLC. When NLC were grown in the stiff substrate, cilengitide and siRNA also significantly reduced the increased expression in αVβ3, ECM components, and proliferation rate. Conclusions: Here, we provide evidence of cilengitide- and siRNA-mediated silencing of αVβ3 integrin expression, and inhibition of ECM synthesis in LC cells. Therefore, αVβ3 integrin may be a promising target for the development of novel anti-fibrotic therapies for treating the LC cupping of the ONH in glaucoma.

Purpose: The integrin αvβ3 and aminopeptidase N (APN/CD13) play vital roles in the tumor angiogenesis process. They are highly expressed in a variety of tumor cells and proliferating endothelial cells during angiogenesis, which have been considered as highly promising targets for tumor imaging. Arginine-glycine-aspartic (RGD) and asparagine-glycine-arginine (NGR) are two peptides specifically binding to the integrin αvβ3 and CD13, respectively. In this study, we optimized our previously developed probe and preclinically evaluated the new integrin αvβ3 and CD13 dual-targeted probe, NOTA-RGD-NGR (denoted as HX01) radiolabeled with 68Ga, in 10 different subcutaneous and orthotopic tumor models. Methods: The specific activity and radiochemical purity of [68Ga]Ga-HX01 were identified. The dual-receptor targeting ability was confirmed by a series of blocking studies and partly muted tracers using BxPC-3 xenograft model. The dynamic imaging study and dose escalation study were explored to determine the optimal imaging time point and dosage in the BxPC-3 xenograft model. Next, we established a variety of subcutaneous and orthotopic tumor models including pancreas (BxPC-3), breast (MCF-7), gallbladder (NOZ), lung (HCC827), ovary (SK-OV-3), colorectal (HCT-8), liver (HuH-7), stomach (NUGC-4), and glioma (U87) cancers. All models underwent [68Ga]Ga-HX01 PET/CT imaging about 2 weeks post-inoculation, with a subset of them undergoing [18F]FDG PET/CT scan performed concurrently, and their results were compared. In addition, ex vivo biodistribution studies were also performed for verifying the semi-quantitative results of the non-invasive PET images. Results: [68Ga]Ga-HX01 significantly outperformed single target probes in the BxPC-3 xenograft model. All blocking and single target groups exhibited significantly descending tumor uptake. The high tumor uptakes were found in BxPC-3, MCF-7, and NOZ subcutaneous tumors (%ID/g > 1.1), while middle uptakes were observed in HCC827, SK-OV-3, HCT-8, and HuH-7 subcutaneous tumor (%ID/g 0.7–1.0). Due to the low background, the tumor-to-muscle and tumor-to-blood ratios of [68Ga]Ga-HX01 were higher than that of [18F]FDG. Conclusions: [68Ga]Ga-HX01, as a dual target imaging agent, exhibited superior in vivo performance in different subcutaneous and orthotopic mice models of human tumors over [18F]FDG and its respectively mono-receptor targeted agents, which warrants the future clinical translation for tumor imaging. [ABSTRACT FROM AUTHOR]

Background: Integrins are closely related to mechanical conduction and play a crucial role in the osteogenesis of human mesenchymal stem cells. Here we wondered whether tensile stress could influence cell differentiation through integrin αVβ3. Methods: We inhibited the function of integrin αVβ3 of human mesenchymal stem cells by treating with c(RGDyk). Using cytochalasin D and verteporfin to inhibit polymerization of microfilament and function of nuclear Yes-associated protein (YAP), respectively. For each application, mesenchymal stem cells were loaded by cyclic tensile stress of 10% at 0.5 Hz for 2 h daily. Mesenchymal stem cells were harvested on day 7 post-treatment. Western blotting and quantitative RT-PCR were used to detect the expression of alkaline phosphatase (ALP), RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining detected vinculin, actin filaments, and YAP nuclear localization. Results: Cyclic tensile stress could increase the expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation led to rearrangement of actin filaments and downregulated the expression of ALP, RUNX2 and promoted YAP nuclear localization. When microfilament polymerization was inhibited, ALP, RUNX2, and nuclear YAP nuclear localization decreased. Inhibition of YAP nuclear localization could reduce the expression of ALP and RUNX2. Conclusions: Cyclic tensile stress promotes early osteogenesis of human mesenchymal stem cells via the integrin αVβ3-actin filaments axis. YAP nuclear localization participates in this process of human mesenchymal stem cells. 7pqm7m_g_KeHaQ8nD7WfNi Video Abstract [ABSTRACT FROM AUTHOR]

The article focuses on the role of von Willebrand factor (VWF) beyond its known function in blood clotting, delving into its regulatory impact on angiogenesis. It explores how individuals with von Willebrand syndrome (VWS), lacking VWF, can exhibit angiodysplasias. Highlighting the VWF's complexity, the article examines its role in angiogenic processes, explaining how reduced VWF expression can amplify endothelial cell proliferation and migration.

Kisspeptin (KP) is a group of hypothalamic neuropeptides encoded by KISS-1 gene. KP-54, a 54-amino-acid peptide, helps regulate the hypothalamic-pituitary-ovarian axis and plays a potential role in implantation. C57BL/6 J female mice were superovulated via intraperitoneal injection of 5 International Units (IU) pregnant mare serum gonadotrophin (day 1). Forty-eight hours later, mice (5/group) were injected with phosphate-buffered saline (PBS) (group A), 5 IU human chorionic gonadotrophin (hCG) (group B), or 3 nmol KP-54 (group C). On day 7, mice were euthanized and uteri excised to create paraformaldehyde-fixed paraffin-embedded sections that were immunostained for the implantation markers: leukemia inhibitory factor (LIF) and integrin αVβ3 (ITG αVβ3). Slides were scored for intensity of staining in endometrial glandular epithelium (GE) and stromal cells (SCs) via histoscore (H-score). Data were analyzed using the Kruskal–Wallis test followed by the Mann–Whitney U test for pairwise comparisons. LIF expression was significantly higher in GE and SCs of mice triggered with KP-54 compared to placebo (P =.009 for both), but only higher than hCG trigger group in SCs (P =.009). Meanwhile, ITG αVβ3 expression was significantly higher in SCs of mice triggered with KP-54 compared to placebo (P =.028). In conclusion, using KP-54 as an ovulation trigger resulted in higher expression of the implantation markers LIF and ITG αVβ3 in mice endometrium compared to hCG or placebo. This suggests a potential role for KP-54 trigger in improving embryo implantation in clinical IVF. However, further studies are needed to correlate these results with clinical implantation rates and pregnancy outcomes. [ABSTRACT FROM AUTHOR]

In osteoarthritis (OA), the articular cartilage covering the articular surface of the bone wears out, exposing the subchondral bone, and the synovial membrane surrounding the joint becomes inflamed, causing pain and deformity. OA causes pain, stiffness, and swelling, and discomfort in the knee when climbing stairs is a typical symptom. Although drug development studies are conducted to treat these inflammatory joint diseases, it is difficult to find conclusive research results which could reduce inflammation and slow cartilage tear. The development of drugs to relieve inflammatory pain often utilizes inflammatory triggers. Interleukins, one of the proteins in the limelight as pro-inflammatory factors, are immune-system-stimulating factors that promote the body's fight against harmful factors such as bacteria. In this study, inflammation was induced in Chondrocytes cells (Chon-001 cells) with IL-1β and then treated with integrin αvβ3 to show anti-inflammatory and chondrogenesis effects. Integrin αvβ3 was not toxic to Chon-001 cells in any concentration groups treated with or without IL-1β. COX-2 and iNOS, which are major markers of inflammation, were significantly reduced by integrin αvβ3 treatment. Expressions of p-ERK, p-JNK, and p-p38 corresponding to the MAPKs signaling pathway and p-IκBα and p-p65 corresponding to the NF-κB signaling pathway were also decreased in a dose-dependent manner upon integrin αvβ3 treatment, indicating that inflammation was inhibited, whereas treatment with integrin αvβ3 significantly increased the expression of ALP, RUNX2, BMP2, BMP4, Aggrecan, SOX9, and COL2A1, suggesting that osteogenesis and chondrogenesis were induced. These results suggest that integrin αvβ3 in-duces an anti-inflammatory effect, osteogenesis, and chondrogenesis on IL-1β-induced Chon-001 cells. [ABSTRACT FROM AUTHOR]

Osteopontin (OPN) is a secreted phosphosylated protein, which is widely found in various tissues and body fluids. OPN involved in various physiological and pathological processes such as bone growth, wound healing and cell adhesion and migration. The integrin αvβ3 is the main receptor for OPN. Recent studies have shown that the high expression level of OPN is closely related to the invasive phenotype and poor prognosis of non-small cell lung cancer (NSCLC) . OPN is expected to become a potential serological biomarker and therapeutic drug target for the disease, which has gradually attracted the attention of researchers at home and abroad. Therefore, this paper presents the structural characteristics of OPN and its correlation with the occurrence, development and treatment prognosis of NSCLC.

The refractoriness of tumor cells to apoptosis represents the main mechanism of resistance to chemotherapy. Smac/DIABLO mimetics proved to be effective in overcoming cancer-acquired resistance to apoptosis as a consequence of overexpression of the anti-apoptotic proteins XIAP, cIAP1, and cIAP2. In this work, we describe a dual-targeting peptide capable of selectively activating apoptosis in cancer cells. The complex consists of a fluorescent periodic mesoporous organosilica nanoparticle that carries the short sequences of Smac/DIABLO bound to the αvβ3--integrin ligand. The dual-targeting peptide @PMO shows significantly higher toxicity in αvβ3-positive HeLa cells with respect to αvβ3-negative Ht29 cells. @PMO exhibited synergistic effects in combination with oxaliplatin in a panel of αvβ3-positive cancer cells, while its toxicity is overcome by XIAP overexpression or integrin β3 silencing. The successful uptake of the molecule by αvβ3-positive cells makes @PMO promising for the re-sensitization to apoptosis of many cancer types. [ABSTRACT FROM AUTHOR]

Androgen has been shown to regulate male physiological activities and cancer proliferation. It is used to antagonize estrogen-induced proliferative effects in breast cancer cells. However, evidence indicates that androgen can stimulate cancer cell growth in estrogen receptor (ER)-positive and ER-negative breast cancer cells via different types of receptors and different mechanisms. Androgen-induced cancer growth and metastasis link with different types of integrins. Integrin αvβ3 is predominantly expressed and activated in cancer cells and rapidly dividing endothelial cells. Programmed death-ligand 1 (PD-L1) also plays a vital role in cancer growth. The part of integrins in action with androgen in cancer cells is not fully mechanically understood. To clarify the interactions between androgen and integrin αvβ3, we carried out molecular modeling to explain the potential interactions of androgen with integrin αvβ3. The androgen-regulated mechanisms on PD-L1 and its effects were also addressed. [ABSTRACT FROM AUTHOR]

Simple Summary: The integrin family of cell surface proteins plays an important role in the development and spread of cancers. Therefore, drugs which inhibit integrins should make effective cancer treatments. Most potential drugs developed so far target a single integrin and have not proved effective at treating cancer in human studies. Our research aims to develop more effective drugs by targeting two related integrins. This paper describes how these potential drug molecules are made, allowing chemists to make better compounds in the future, and describes the anti-integrin effects of the new compounds. Together this information will lead to the future design and development of better anticancer drugs. The Arg-Gly-Asp (RGD)-binding family of integrin receptors, and notably the β3 subfamily, are key to multiple physiological processes involved in tissue development, cancer proliferation, and metastatic dissemination. While there is compelling preclinical evidence that both αvβ3 and αIIbβ3 are important anticancer targets, most integrin antagonists developed to target the β3 integrins are highly selective for αvβ3 or αIIbβ3. We report the design, synthesis, and biological evaluation of a new structural class of ligand-mimetic β3 integrin antagonist. These new antagonists combine a high activity against αvβ3 with a moderate affinity for αIIbβ3, providing the first evidence for a new approach to integrin targeting in cancer. [ABSTRACT FROM AUTHOR]

Abstract Background High-risk differentiated thyroid cancer (DTC) needs effective early prediction tools to improving clinical management and prognosis. This cohort study aimed to investigate the prognostic impact of 99mTc-PEG4-E[PEG4-c(RGDfK)]2 (99mTc-3PRGD2) SPECT/CT in high-risk DTC patients after initial radioactive iodine (RAI) therapy. Methods Thirty-three patients with high-risk DTC were prospectively recruited; all patients underwent total thyroidectomy and received 99mTc-3PRGD2 SPECT/CT before RAI ablation. Follow-up was done with serological and imaging studies. The correlation between 99mTc-3PRGD2 avidity and remission rate for initial RAI therapy was evaluated using logistic regression analysis. The prognostic value of 99mTc-3PRGD2 SPECT/CT was evaluated by Kaplan-Meier curve and Cox regression analysis. Results 99mTc-3PRGD2 avidity was significantly correlated with the efficacy of initial RAI ablation and an effective predictor for non-remission in high-risk DTC (OR = 9.36; 95% CI = 1.10–79.83; P = 0.041). 99mTc-3PRGD2 avidity was associated with poor prognosis in patients with high-risk DTC and an independent prognostic factor for shorter progression-free survival (PFS) (HR = 9.47; 95% CI = 1.08–83.20; P = 0.043). Survival analysis, which was performed between DTC patients with concordant (131I positive/99mTc-3PRGD2 positive) and discordant (131I negative/99mTc-3PRGD2 positive) lesions, indicated that patients with concordant lesions had significantly better PFS than those with discordant lesions (P = 0.022). Moreover, compared with repeated RAI, additional surgery or targeted therapy with multikinase inhibitors could lead to a higher rate of remission in 99mTc-3PRGD2-positive patients with progressive disease. Conclusions 99mTc-3PRGD2 SPECT/CT is a useful modality in predicting progression of the disease after initial RAI and guiding further treatment in high-risk DTC patients.

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs. Key players mediating fibrosis are myofibroblasts (MF) that, following transforming growth factor β (TGFβ) exposure, produce a collagen-rich extracellular matrix (ECM) that induces myofibroblast differentiation. Myofibroblasts express αvβ3 integrin (a membrane receptor for thyroid hormones) and miRNA-21 that promotes deiodinase-type-3 expression (D3), causing the degradation of triiodothyronine (T3) that attenuates fibrosis. We hypothesized that αvβ3 affects the fibrotic processes through its thyroid hormones (THs) binding site. To test this, dermal fibroblasts (DF) were cultured with/without TGFβ and removed with a base, leaving only normal/fibrotic ECMs in wells. Then, DF were cultured on the ECMs with/without tetrac (αvβ3 ligand, T4 antagonist), and evaluated for pro-fibrotic characteristics, αvβ3, miRNA-21, and D3 levels. Blood free-T3 (fT3), miRNA-21 levels, and the modified Rodnan skin score (MRSS) were evaluated in SSc patients. We found that the "fibrotic-ECM" significantly increased the pro-fibrotic characteristics of DF and the levels of miRNA-21, D3, and αvβ3, compared to the "normal-ECM." Tetrac significantly inhibited the effects of the "fibrotic-ECM" on the cells. In accordance with tetrac's effect on D3/miRNA-21, a negative correlation was found between the patients' fT3 to miRNA-21 levels, and to the development of pulmonary arterial hypertension (PAH). We conclude that occupying the THs binding site of αvβ3 may delay the development of fibrosis. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is believed to be linked with cartilage degeneration, subchondral bone sclerosis, and synovial inflammation that lead to joint failure, and yet treatment that can effectively reverse the pathological process of the disease still not exists. Recent evidence suggests excessive mechanical stress (eMS) as an essential role in the pathogenesis of OA. Increased levels of integrin αVβ3 have been detected in osteoarthritic cartilage and were previously implicated in OA pathogenesis. However, the role of integrin αVβ3 in the process of eMS-induced OA remains unclear. Here, histologic and proteomic analyses of osteoarthritic cartilage in a rat destabilization of the medial meniscus model demonstrated elevated expression of integrin αVβ3 as well as more serious cartilage degeneration in the medial weight-bearing area. Furthermore, results of in vitro study demonstrated that eMS led to a significant increase of integrin αVβ3 expression and phosphorylation of downstream signaling molecules such as FAK and ERK, as well as upregulated expressions of inflammatory and degradative mediators. In addition, we found that inhibition of integrin αVβ3 could alleviate chondrocyte inflammation triggered by eMS both in vivo and in vitro. Our findings suggest a central role for upregulation of integrin αVβ3 signaling in OA pathogenesis and demonstrate that activation of integrin αVβ3 signaling in cartilage contributes to inflammation and joint destruction in eMS-induced OA. Taken together, our data presented here provide a possibility for targeting integrin αVβ3 signaling pathway as a disease-modifying therapy. [ABSTRACT FROM AUTHOR]

Low molecular weight RGD peptides and RGD mimetics are widely studied as ligands targeting the corresponding receptor in the diagnosis and therapy of cancer, as well as in the field of bone tissue regeneration. Some of them are undergoing preclinical trials. The aim of this study is to select the optimal variants of the ligand structure based on an aliphatic RGD mimetic. By methods of molecular modeling (blind docking and active site docking), the most advantageous constructions for the formation of a stable complex with the integrin αVβ3 are determined. A scheme is developed and two lipotripeptides Gnd-GABA-Gly-Asp(C16)2 and Gnd-β-Ala-Gly-Asp(C16)2 with the potential ability to inhibit this receptor on the surface of tumor tissues are synthesized. [ABSTRACT FROM AUTHOR]

The tumor microenvironment, especially the extracellular matrix (ECM), is strongly associated with tumor cell proliferation and metastasis. Numerous studies have provided evidence suggesting that fibronectin (FN) in ECM supports cancer cell escape and contributes to cell migration, resulting in distant cancer metastasis and poor outcomes in patients. In our study, it was demonstrated that FN expression was elevated in tumor tissues from highly malignant NSCLC patients, compared to those with low malignancy (p = 0.0076). Importantly, FN promoted proliferative phenotypes and strengthened tumorigenesis capabilities in NSCLC cells, including A549 and Lewis cells, leading to sustained tumor growth in vivo. Mechanistically, it was identified that FN facilitated the activation of the integrin αvβ3/PI3K/AKT signaling pathway, which subsequently upregulated tumor stemness through the downstream transcription factor SOX2. Blockade of integrin αvβ3 signal efficiently suppressed NSCLC proliferation and tumorigenesis both in vitro and in vivo. In conclusion, our study demonstrated that extracellular FN could facilitate NSCLC development through the integrin αvβ3/PI3K/AKT/SOX2 signaling pathway. Blockade of integrin αvβ3 could efficiently enhance the anticancer effects of chemotherapy, offering an innovative approach for clinical NSCLC therapy.