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130 result(s) for "Integrin alpha2 - genetics"
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A phase I, dose escalation, pharmacodynamic, pharmacokinetic, and food-effect study of α2 integrin inhibitor E7820 in patients with advanced solid tumors
Summary Introduction E7820 is an orally administered sulfonamide that inhibits alfa-2-integrin mRNA expression. Pre-clinically E7820 showed tumor anti-angiogenic effects in various tumor cell lines and xenograft mouse models. Human daily dosing of 100 mg QD had previously been shown to be safe and tolerable. Methods The study consisted of two parts: Part A (food effect) and Part B (determination of maximum tolerated dose (MTD) for bi-daily (BID) dosing). E7820 dosing started at 50 mg BID with planned escalation to 60, 80 and 100 mg BID every 28 days. Results Fifteen patients were enrolled in Part A and 26 in Part B. The most frequent adverse events of all grades were constipation, diarrhea, nausea, and fatigue while anemia, neutropenia, and fatigue were most frequent grade ≥3 toxicities. At dose-level 60 mg BID, two patients experienced dose-limiting toxicities (grade 3 neutropenic sepsis and grade 4 neutropenia). Therefore the recommended dose (RD) was 50 mg BID. Food had no effect on E7820 exposure. E7820 exposure following twice daily administration was dose-proportional. Expression of platelet integrin-α 2 measured as a response biomarker in Part B, generally decreased by a median 7.7 % from baseline following treatment with 50 mg BID E7820. Reduction was most pronounced within 1-week post treatment. The median duration of treatment was median 54, range 20–111 days. The best overall response in any treatment group was stable disease (SD): 23.1 % in Part A (100 mg QD); at the RD 66.7 % (12 of 18 patients) and 40 % in the 60 mg BID group in Part B. Conclusions :Food had no effect on E7820 exposure. A dose of 50 mg BID was considered the MTD. Treatment with E7820 is safe and tolerable with 2/3 of patients (66.7 %) at MTD having SD as their best response.
Distinct biophysical mechanisms of focal adhesion kinase mechanoactivation by different extracellular matrix proteins
Matrix mechanics controls cell fate by modulating the bonds between integrins and extracellular matrix (ECM) proteins. However, it remains unclear how fibronectin (FN), type 1 collagen, and their receptor integrin subtypes distinctly control force transmission to regulate focal adhesion kinase (FAK) activity, a crucial molecular signal governing cell adhesion/migration. Here we showed, using a genetically encoded FAK biosensor based on fluorescence resonance energy transfer, that FN-mediated FAK activation is dependent on the mechanical tension, which may expose its otherwise hidden FN synergy site to integrin α5. In sharp contrast, the ligation between the constitutively exposed binding motif of type 1 collagen and its receptor integrin α2 was surprisingly tension-independent to induce sufficient FAK activation. Although integrin α subunit determines mechanosensitivity, the ligation between α subunit and the ECM proteins converges at the integrin β1 activation to induce FAK activation. We further discovered that the interaction of the N-terminal protein 4.1/ezrin/redixin/moesin basic patch with phosphatidylinositol 4,5-biphosphate is crucial during cell adhesion to maintain the FAK activation from the inhibitory effect of nearby protein 4.1/ezrin/redixin/moesin acidic sites. Therefore, different ECM proteins either can transmit or can shield from mechanical forces to regulate cellular functions, with the accessibility of ECM binding motifs by their specific integrin α subunits determining the biophysical mechanisms of FAK activation during mechanotransduction.
αIIbβ3 variants in ten families with autosomal dominant macrothrombocytopenia: Expanding the mutational and clinical spectrum
Rare pathogenic variants in either the ITGA2B or ITGB3 genes have been linked to autosomal dominant macrothrombocytopenia associated with abnormal platelet production and function, deserving the designation of Glanzmann Thrombasthenia-Like Syndrome (GTLS) or ITGA2B/ITGB3-related thrombocytopenia. To describe a series of patients with familial macrothrombocytopenia and decreased expression of αIIbβ3 integrin due to defects in the ITGA2B or ITGB3 genes. We reviewed the clinical and laboratory records of 10 Portuguese families with GTLS (33 patients and 11 unaffected relatives), including the functional and genetic defects. Patients had absent to moderate bleeding, macrothrombocytopenia, low αIIbβ3 expression, impaired platelet aggregation/ATP release to physiological agonists and low expression of activation-induced binding sites on αIIbβ3 (PAC-1) and receptor-induced binding sites on its ligand (bound fibrinogen), upon stimulation with TRAP-6 and ADP. Evidence for constitutive αIIbβ3 activation, occurred in 2 out of 9 patients from 8 families studied, but also in 2 out of 12 healthy controls. We identified 7 missense variants: 3 in ITGA2B (5 families), and 4 in ITGB3 (5 families). Three variants (αIIb: p.Arg1026Trp and p.Arg1026Gln and β3: p.Asp749His) were previously reported. The remaining (αIIb: p.Gly1007Val and β3: p.Thr746Pro, p.His748Pro and p.Arg760Cys) are new, expanding the αIIbβ3 defects associated with GTLS. The integration of the clinical and laboratory data allowed the identification of two GTLS subgroups, with distinct disease severity. Previously reported ITGA2B and ITGB3 variants related to thrombocytopenia were clustered in a confined region of the membrane-proximal cytoplasmic domains, the inner membrane clasp. For the first time, variants are reported at the outer membrane clasp, at the transmembrane domain of αIIb, and at the membrane distal cytoplasmic domains of β3. This is the largest single-center series of inherited macrothrombocytopenia associated with αIIbβ3 variants published to date.
Overexpressed ITGA2 promotes malignant tumor aggression by up-regulating PD-L1 expression through the activation of the STAT3 signaling pathway
Background Recent studies have reported that Integrin alpha 2 (ITGA2) plays an essential role in tumor cell proliferation, invasion, metastasis, and angiogenesis. An abnormally expressed ITGA2 correlates with unfavorable prognoses in multiple types of cancer. However, the specific mechanism of how ITGA2 contributes to tumorigenesis remains unclear. Methods The GEPIA web tool was used to find the clinical relevance of ITGA2 in cancer, and this significance was verified using Western blotting analysis of paired patient tissues and immunohistochemistry of the pancreatic cancer tissue. Functional assays, such as the MTS assay, colony formation assay, and transwell assay, were used to determine the biological role of ITGA2 in human cancer. The relationship between ITGA2 and programmed death-ligand 1 (PD-L1) was examined using Western blot analysis, RT-qPCR assay, and immunohistochemistry. The protein-protein interaction between ITGA2 and STAT3 was detected via co-immunoprecipitation. Results Our study showed that ITGA2 was markedly overexpressed in several malignant tumor cells and clinical tissues. Blocking ITGA2 inhibited the proliferation and invasion ability of cancer cells significantly, whereas overexpressed ITGA2 increased the degree of those processes considerably. Additionally, the RNA-seq assay indicated that ITGA2 transcriptionally regulated the expression of PD-L1 in pancreatic cancer. We also demonstrated that ITGA2 interacted with STAT3 and up-regulated the phosphorylation of STAT3; this interaction might involve the mechanism of ITGA2 inducing PD-L1 expression in cancer cells. Our results suggest that ITGA2 plays a critical role in cancer cell progression and the regulation of PD-L1 by activating the STAT3 pathway. Conclusions We identified a novel mechanism by which ITGA2 plays a critical role in modulating cancer immune response by transcriptionally increasing the expression of PD-L1 in cancer cells. Thus, targeting ITGA2 is an effective method to enhance the efficacy of checkpoint immunotherapy against cancer.
ITGA2B / ITGB3 ‐Related Macrothrombocytopenia Associated With Gain‐of‐Function Mutations in ITGA2B or ITGB3 Genes
Glanzmann thrombasthenia (GT) is an inherited hemorrhagic disorder characterised by impaired platelet functions, manifested clinically as spontaneous bleeding. It is usually inherited in an autosomal recessive manner. Platelet dysfunction in patients with GT is caused by quantitative and/or qualitative deficiencies in αIIbβ3, which result from mutations in the genes encoding αIIbβ3. These genetic alterations lead to platelet dysfunction characterised by impaired fibrinogen binding capacity upon agonist stimulation, defective aggregation and spreading. While classical GT typically exhibits normal platelet counts and morphology, very rare mutations in ITGA2B ( encoding αIIb) and/or ITGB3 ( encoding β3) cause macrothrombocytopenia or increased platelet anisotropy (heterogeneity of platelet size and morphology). This type of mutation mainly localises in the membrane‐proximal region of αIIbβ3 and is inherited in an autosomal dominant manner. This particular type of disorder is called ITGA2B / ITGB3 ‐related macrothrombocytopenia and has been considered a subset of congenital macrothrombocytopenia. Current research suggests that gain‐of‐function mutations in ITGA2B or ITGB3 underlie the pathogenesis of most ITGA2B / ITGB3 ‐related macrothrombocytopenia and mechanistically distinguish it from classical GT. However, recent reports have documented non‐activating ITGB3 mutations that also cause macrothrombocytopenia, presenting a profound challenge to the mechanistic understanding of ITGA2B/ITGB3 ‐related macrothrombocytopenia. This review summarises the reported cases of gain‐of‐function mutations in ITGA2B and ITGB3 associated with ITGA2B / ITGB3 ‐related macrothrombocytopenia hitherto and discusses the potential molecular pathways contributing to the unique phenotypes in ITGA2B / ITGB3 ‐related macrothrombocytopenia.
Platelet-targeted gene therapy with human factor VIII establishes haemostasis in dogs with haemophilia A
It is essential to improve therapies for controlling excessive bleeding in patients with haemorrhagic disorders. As activated blood platelets mediate the primary response to vascular injury, we hypothesize that storage of coagulation Factor VIII within platelets may provide a locally inducible treatment to maintain haemostasis for haemophilia A. Here we show that haematopoietic stem cell gene therapy can prevent the occurrence of severe bleeding episodes in dogs with haemophilia A for at least 2.5 years after transplantation. We employ a clinically relevant strategy based on a lentiviral vector encoding the ITGA2B gene promoter, which drives platelet-specific expression of human FVIII permitting storage and release of FVIII from activated platelets. One animal receives a hybrid molecule of FVIII fused to the von Willebrand Factor propeptide-D2 domain that traffics FVIII more effectively into α-granules. The absence of inhibitory antibodies to platelet-derived FVIII indicates that this approach may have benefit in patients who reject FVIII replacement therapies. Thus, platelet FVIII may provide effective long-term control of bleeding in patients with haemophilia A. Haemophilia is a genetic bleeding disorder associated with a deficiency in the coagulation factor VIII. Here, the authors use gene therapy to achieve stable overexpression of factor VIII in platelets of dogs with haemophilia A, preventing the occurrence of severe bleeding episodes for over 2.5 years.
ITGA2, LAMB3, and LAMC2 may be the potential therapeutic targets in pancreatic ductal adenocarcinoma: an integrated bioinformatics analysis
Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer with an abysmal prognosis rate over the last few decades. Early diagnosis and prevention could effectively combat this malignancy. Therefore, it is crucial to discover potential biomarkers to identify asymptomatic premalignant or early malignant tumors of PDAC. Gene expression analysis is a powerful technique to identify candidate biomarkers involved in disease progression. In the present study, five independent gene expression datasets, including 321 PDAC tissues and 208 adjacent non-cancerous tissue samples, were subjected to statistical and bioinformatics analysis. A total of 20 differentially expressed genes (DEGs) were identified in PDAC tissues compared to non-cancerous tissue samples. Gene ontology and pathway enrichment analysis showed that DEGs were mainly enriched in extracellular matrix (ECM), cell adhesion, ECM–receptor interaction, and focal adhesion signaling. The protein–protein interaction network was constructed, and the hub genes were evaluated. Collagen type XII alpha 1 chain (COL12A1), fibronectin 1 (FN1), integrin subunit alpha 2 (ITGA2), laminin subunit beta 3 (LAMB3), laminin subunit gamma 2 (LAMC2), thrombospondin 2 (THBS2), and versican (VCAN) were identified as hub genes. The correlation analysis revealed that identified hub genes were significantly interconnected. Wherein COL12A1, FN1, ITGA2, LAMB3, LAMC2, and THBS2 were significantly associated with PDAC pathological stages. The Kaplan–Meier survival plots revealed that ITGA2, LAMB3, and LAMC2 expression were inversely correlated with a prolonged patient survival period. Furthermore, the Human Protein Atlas database was used to validate the expression and cellular origins of hub genes encoded proteins. The protein expression of hub genes was higher in pancreatic cancer tissue than in normal pancreatic tissue samples, wherein ITGA2, LAMB3, and LAMC2 were exclusively expressed in pancreatic cancer cells. Pancreatic cancer cell-specific expression of these three proteins may play pleiotropic roles in cancer progression. Our results collectively suggest that ITGA2, LAMB3, and LAMC2 could provide deep insights into pancreatic carcinogenesis molecular mechanisms and provide attractive therapeutic targets.
MUC1 promotes cervical squamous cell carcinoma through ERK phosphorylation-mediated regulation of ITGA2/ITGA3
In contrast to the decreasing trends in developed countries, the incidence and mortality rates of cervical squamous cell carcinoma in China have increased significantly. The screening and identification of reliable biomarkers and candidate drug targets for cervical squamous cell carcinoma are urgently needed to improve the survival rate and quality of life of patients. In this study, we demonstrated that the expression of MUC1 was greater in neoplastic tissues than in non-neoplastic tissues of the cervix, and cervical squamous cell carcinoma patients with high MUC1 expression had significantly worse overall survival than did those with low MUC1 expression, indicating its potential for early diagnosis of cervical squamous cell carcinoma. Next, we explored the regulatory mechanism of MUC1 in cervical squamous cell carcinoma. MUC1 could upregulate ITGA2 and ITGA3 expression via ERK phosphorylation, promoting the proliferation and metastasis of cervical cancer cells. Further knockdown of ITGA2 and ITGA3 significantly inhibited the tumorigenesis of cervical cancer cells. Moreover, we designed a combination drug regimen comprising MUC1-siRNA and a novel ERK inhibitor in vivo and found that the combination of these drugs achieved better results in animals with xenografts than did MUC1 alone. Overall, we discovered a novel regulatory pathway, MUC1/ERK/ITGA 2/3 , in cervical squamous cell carcinoma that may serve as a potential biomarker and therapeutic target in the future. Summary MUC1 is overexpressed in cervical squamous cell carcinoma. MUC1 regulates ERK phosphorylation, and subsequently upregulates ITGA2 and ITGA3 expression to promote tumorigenesis in cervical squamous cell carcinoma. A combination drug regimen targeting MUC1 and ERK achieved better results compared than MUC1 alone.
Rare variants in axonogenesis genes connect three families with sound–color synesthesia
Synesthesia is a rare nonpathological phenomenon where stimulation of one sense automatically provokes a secondary perception in another. Hypothesized to result from differences in cortical wiring during development, synesthetes show atypical structural and functional neural connectivity, but the underlying molecular mechanisms are unknown. The trait also appears to be more common among people with autism spectrum disorder and savant abilities. Previous linkage studies searching for shared loci of large effect size across multiple families have had limited success. To address the critical lack of candidate genes, we applied whole-exome sequencing to three families with sound–color (auditory–visual) synesthesia affecting multiple relatives across three or more generations. We identified rare genetic variants that fully cosegregate with synesthesia in each family, uncovering 37 genes of interest. Consistent with reports indicating genetic heterogeneity, no variants were shared across families. Gene ontology analyses highlighted six genes—COL4A1, ITGA2, MYO10, ROBO3, SLC9A6, and SLIT2—associated with axonogenesis and expressed during early childhood when synesthetic associations are formed. These results are consistent with neuroimaging-based hypotheses about the role of hyperconnectivity in the etiology of synesthesia and offer a potential entry point into the neurobiology that organizes our sensory experiences.
The integrin α2-osteoclast axis: a key driver of bone destruction and therapeutic target in osteosarcoma
Background Osteosarcoma is an aggressive bone malignancy with elusive core driving mechanisms. Dysregulated expression of integrin α2 (ITGA2) promotes malignant progression in multiple cancers, yet its role in osteosarcoma and correlation with bone destruction remain poorly understood. This study investigated the potential role of ITGA2 in osteosarcoma progression and therapeutic targeting. Methods Integrating bioinformatics analysis and experimental validation, we explored ITGA2 dysregulation and its clinical significance in osteosarcoma. Public databases were analyzed to confirm ITGA2 overexpression. CCK-8 assay, colony formation, Transwell migration/invasion assays, wound healing, and cell transcriptomics were employed to assess ITGA2’s impact on tumor proliferation, migration, and invasion. Xenograft mouse models evaluated ITGA2-driven tumor growth and osteolytic damage. WB analyzed ITGA2-mediated modulation of osteoclast differentiation-related molecules (RANKL, MMP9, OPN). ITGA2 knockdown and inhibitor (E7820) intervention were applied, with Western Blot (WB)/ Immunohistochemistry (IHC) validating ITGA2-MMP9 interactions. Results Clinical cohorts and bioinformatics revealed ITGA2-specific overexpression in osteosarcoma tissues/cells (P < 0.0001), correlating with poor prognosis (HR = 3.392). Pathway analysis linked ITGA2 to bone remodeling and osteoclast differentiation. Functional assays showed that ITGA2 inhibition decreased cell proliferation and migration/invasion by 2–threefold (all P < 0.001), and reduced tumor volume and decreased osteoclast numbers (TRAP staining) in mouse models. Mechanistically, ITGA2 blockade downregulated MMP9 (pro-osteoclast) and upregulated OPN (pro-osteogenesis), indicating its role in exacerbating bone destruction via osteoclast differentiation cascades. ITGA2 emerged as an independent prognostic biomarker. Conclusion This study uncovered that ITGA2 drives osteosarcoma progression and aggravates osteolysis via the “ITGA2-osteoclast axis”, with high expression predicting poor outcomes. Mechanistically, ITGA2 promoted tumor invasion and bone metabolism imbalance by regulating osteoclastogenic signaling, while its targeted inhibition synergistically suppresses tumor growth and restores bone homeostasis, highlighting ITGA2 as a pivotal therapeutic target for osteosarcoma.