Targeting Integrin α3 Blocks ß1 Maturation, Triggers Endoplasmic Reticulum Stress, and Sensitizes Glioblastoma Cells to TRAIL-Mediated Apoptosis.

Glioblastoma (GBM) is a devastating brain cancer for which new effective therapies are urgently needed. GBM, after an initial response to current treatment regimens, develops therapeutic resistance, leading to rapid patient demise. Cancer cells exhibit an inherent elevation of endoplasmic reticulum (ER) stress due to uncontrolled growth and an unfavorable microenvironment, including hypoxia and nutrient deprivation. Cancer cells utilize the unfolded protein response (UPR) to maintain ER homeostasis, and failure of this response promotes cell death. In this study, as integrins are upregulated in cancer, we have evaluated the therapeutic potential of individually targeting all αß1 integrin subunits using RNA interference. We found that GBM cells are uniquely susceptible to silencing of integrin α3. Knockdown of α3-induced proapoptotic markers such as PARP cleavage and caspase 3 and 8 activation. Remarkably, we discovered a non-canonical function for α3 in mediating the maturation of integrin ß1. In its absence, generation of full length ß1 was reduced, immature ß1 accumulated, and the cells underwent elevated ER stress with upregulation of death receptor 5 (DR5) expression. Targeting α3 sensitized TRAIL-resistant GBM cancer cells to TRAIL-mediated apoptosis and led to growth inhibition. Our findings offer key new insights into integrin α3's role in GBM survival via the regulation of ER homeostasis and its value as a therapeutic target.

ITGA3 acts as a purity-independent biomarker of both immunotherapy and chemotherapy resistance in pancreatic cancer: bioinformatics and experimental analysis.

Contribution of integrin superfamily genes to treatment resistance remains uncertain. Genome patterns of thirty integrin superfamily genes were analyzed of using bulk and single-cell RNA sequencing, mutation, copy number, methylation, clinical information, immune cell infiltration, and drug sensitivity data. To select the integrins that are most strongly associated with treatment resistance in pancreatic cancer, a purity-independent RNA regulation network including integrins were constructed using machine learning. The integrin superfamily genes exhibit extensive dysregulated expression, genome alterations, epigenetic modifications, immune cell infiltration, and drug sensitivity, as evidenced by multi-omics data. However, their heterogeneity varies among different cancers. After constructing a three-gene (TMEM80, EIF4EBP1, and ITGA3) purity-independent Cox regression model using machine learning, ITGA3 was identified as a critical integrin subunit gene in pancreatic cancer. ITGA3 is involved in the molecular transformation from the classical to the basal subtype in pancreatic cancer. Elevated ITGA3 expression correlated with a malignant phenotype characterized by higher PD-L1 expression and reduced CD8+ T cell infiltration, resulting in unfavorable outcomes in patients receiving either chemotherapy or immunotherapy. Our findings suggest that ITGA3 is an important integrin in pancreatic cancer, contributing to chemotherapy resistance and immune checkpoint blockade therapy resistance.

Integrin α3 Mediates Stemness and Invasion of Glioblastoma by Regulating POU3F2.

BACKGROUND: Glioblastoma (GBM) is an aggressive brain tumor. Integrins have been implicated in the malignancy of GBM. A recent study demonstrated that integrin α3 (ITGA3) promoted the invasion of breast cancer cells by regulating transcriptional factor POU3F2. However, whether this also happened in GBM remained unknown. METHODS: Therefore, we explored the relationship between ITGA3 and POU3F2 in GBM. We measured the expression of ITGA3 and POU3F2 in GBM tissues. We generated ITGA3 knockdown and POU3F2 knockdown GBM U87MG cells and the proliferation, migration and invasion, the expression of stemness markers and epithelial to mesenchymal transition (EMT) markers were measured. We transplanted ITGA3 knockdown and POU3F2 knockdown GBM U87MG cells into mice. The mice were treated with anti-ITGA3 antibody. The tumor sizes, the expression of stemness markers and epithelial-to-mesenchymal transition (EMT) markers were measured. RESULTS: Both ITGA3 and POU3F2 were upregulated in GBM tissues. Knocking down ITGA3 resulted in reduced expression of POU3F2. Knocking down ITGA3 and POU3F2 suppressed U87MG cells proliferation, migration and invasion, inhibited the expression of stemness markers and prevented epithelial- to-mesenchymal transition. The transplantation of ITGA3 knockdown and POU3F2 knockdown U87MG cells decreased tumor size. CONCLUSION: Anti-ITGA3 antibody treatment reduced the tumor size. ITGA3 regulates stemness and invasion of glioblastoma through POU3F2.

YY1/ITGA3 pathway may affect trophoblastic cells migration and invasion ability.

Recurrent spontaneous abortion (RSA) is a disturbing pregnancy disorder experienced by ~2.5% of women attempting to conceive. The pathogenesis of RSA is still unclear. Previous findings revealed that transcription factor YIN-YANG 1(YY1) was related to the pathogenesis of RSA by influence trophoblastic cell invasion ability. Present study aimed to investigate more specific molecular mechanism of YY1 playing in trophoblastic cells. In our research, RNA-seq and Chip-seq were used to find significant changed genes between si-YY1(Knock down of YY1) HTR-8/SVneo cells(n = 3) and HTR-8/SVneo cells(n = 3). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis results suggested that Integrins related pathway maybe necessary to biological functions of trophoblastic cells. Chip-seq dataset analysis results predict YY1 can regulate ITGA3/7 expression by binding to the promoter region of ITGA3/7. Furthermore, results from chip experiment, RT-PCR, Dual-luciferase reporter gene assay showed that YY1 was able to bind to the promoter region of ITGA3 and regulate ITGA3 mRNA and protein expression. However, ITGA7 could not be significant influenced by YY1. Besides, gene silencing experiment, Western blot and Immunofluorescence assay confirmed that both YY1 and ITGA3 can accelerate phosphorylation focal adhesion kinase and affect cytoskeleton formation in HTR-8/SVneo cells. In conclusion, YY1/ITGA3 play a critical role in trophoblast invasion ability by regulating cytoskeleton formation.

Zebrafish integrin a3b is required for cardiac contractility and cardiomyocyte proliferation.

In cardiac muscle cells, heterodimeric integrin transmembrane receptors are known to serve as mechanotransducers, translating mechanical force to biochemical signaling. However, the roles of many individual integrins have still not been delineated. In this report, we demonstrate that Itga3b is localized to the sarcolemma of cardiomyocytes from 24 to 96 hpf. We further show that heterozygous and homozygous itga3b/bdf mutant embryos display a cardiomyopathy phenotype, with decreased cardiac contractility and reduced cardiomyocyte number. Correspondingly, proliferation of ventricular and atrial cardiomyoctyes and ventricular epicardial cells is decreased in itga3b mutant hearts. The contractile dysfunction of itga3b mutants can be attributed to cardiomyocyte sarcomeric disorganization, including thin myofilaments with blurred and shortened Z-discs. Together, our results reveal that Itga3b localizes to the myocardium sarcolemma, and it is required for cardiac contractility and cardiomyocyte proliferation.

miRNA-144-5p/ITGA3 Suppressed the Tumor-Promoting Behaviors of Thyroid Cancer Cells by Downregulating ITGA3.

OBJECTIVE: To ascertain the mechanism of miRNA-144-5p and ITGA3 in thyroid cancer (TC). METHODS: From The Cancer Genome Atlas (TCGA), RNA expression profiles were obtained for the expression analysis of miRNAs and mRNAs in TC. qRT-PCR and western blot were utilized to measure the expression of miRNA-144-5p and ITGA3 at RNA and protein levels, respectively. The association between miRNA-144-5p and ITGA3 was validated by the dual-luciferase assay. CCK-8, scratch healing, transwell, and flow cytometry assays were employed to evaluate tumor-related cell behaviors. RESULTS: Low-expressed miRNA-144-5p and high-expressed ITGA3 were found in TC cells relative to normal cells. miRNA-144-5p expression was positively associated with suppressive effects on proliferative, invasive, and migratory ability of TC cells while negatively associated with cell apoptosis. miRNA-144-5p inhibited ITGA3 expression in TC, and its overexpression remarkably reversed the tumor-promoting effects of overexpressed ITGA3 on the biological functions of TC. CONCLUSION: It is verified in our study that cell growth of TC is inhibited by the miRNA-144-5p/ITGA3 axis, which represents an underlying target for TC. This research proposed a new insight into the strategy of TC treatment.

A novel ITGA3 homozygous splice mutation in an ILNEB syndrome child with slow progression.

BACKGROUND AND AIMS: ILNEB (interstitial lung disease, nephrotic syndrome, epidermolysis bullosa) syndrome is caused by ITGA3 mutations. Demises usually happened at infancy. This study reports a complete ILNEB syndrome child with slow disease progression. MATERIALS AND METHODS: Clinical data and related specimens were collected. Genomic DNA was extracted for genetic sequencing. Integrin α3 expression was detected by western blotting and immunofluorescence staining. RESULTS: The patient was male. He experienced recurrent rashes shortly after birth. His sparse eyebrows and eyelashes gradually lost. The patient was vulnerable to respiratory infections and had recurrent fever after vaccine immunization after 4 years. He was found with nephrotic syndrome and polycystic renal dysplasia at 8 years and progressed to end-stage renal disease at 12 years. A chest Computed Tomography revealed intestinal lung disease at 8 years. Continuous oxygen supplementation was needed at 13 years. Counts of lymphocyte subsets revealed elevated percentage of double-negative T cells and activated T cells. Next-generation sequencing revealed a novel homozygous splice mutation c.2219 + 4A > Cin ITGA3 that was predicted to be deleterious. The mutation resulted in exon17 skipping with the loss of 80 bp in the mRNA. The aberrant integrin α3 mRNA level was lower compared to the healthy control. Integrin α3 protein was not detected in urine epithelial cells and skin of the patient. CONCLUSIONS: We report a patient harboring a novel ITGA3 homozygous splice mutation who presented with complete ILNEB syndrome but slow disease progression. Immune disorders were suspected.

First patient with ILNEB syndrome due to pathogenic variants in ITGA3 surviving to adulthood.

Interstitial Lung disease, Nephrotic syndrome and Epidermolysis Bullosa, also referred to as ILNEB syndrome is an extremely rare autosomal recessive condition, caused by pathogenic variants in ITGA3. 11 patients have previously been diagnosed with ILNEB syndrome of whom 7 died in infancy or early childhood. We report the only patient with ILNEB syndrome who survived past adolescence, partly due to a double lung transplant. Additionally, our patient showed oral, nasal and gynecological symptoms not previously reported in patients with ILNEB syndrome.

CD9 and ITGA3 are regulated during HIV-1 infection in macrophages to support viral replication.

Monocytes/macrophages are important target cells for HIV-1. Here, we investigated whether HIV-1 induces changes in the macrophage gene expression profile to support viral replication. We observed that the macrophage gene expression profiles dramatically changed upon HIV-1 infection. The majority of the HIV-1 regulated genes were also differentially expressed in M2a macrophages. The biological functions associated with the HIV-1 induced gene expression profile in macrophages were mainly related to inflammatory responses. CD9 and ITGA3 were among the top genes upregulated upon HIV-1 infection. We showed that these genes support viral replication and that downregulation of these genes decreased HIV-1 replication in macrophages. Here we showed that HIV-1 infection of macrophages induces a gene expression profile that may dampen inflammatory responses. CD9 and ITGA3 were among the top genes regulated by HIV-1 and were shown to support viral production most likely at the level of viral budding and release.

Variability within rare cell states enables multiple paths toward drug resistance.

Molecular differences between individual cells can lead to dramatic differences in cell fate, such as death versus survival of cancer cells upon drug treatment. These originating differences remain largely hidden due to difficulties in determining precisely what variable molecular features lead to which cellular fates. Thus, we developed Rewind, a methodology that combines genetic barcoding with RNA fluorescence in situ hybridization to directly capture rare cells that give rise to cellular behaviors of interest. Applying Rewind to BRAFV600E melanoma, we trace drug-resistant cell fates back to single-cell gene expression differences in their drug-naive precursors (initial frequency of ~1:1,000-1:10,000 cells) and relative persistence of MAP kinase signaling soon after drug treatment. Within this rare subpopulation, we uncover a rich substructure in which molecular differences among several distinct subpopulations predict future differences in phenotypic behavior, such as proliferative capacity of distinct resistant clones after drug treatment. Our results reveal hidden, rare-cell variability that underlies a range of latent phenotypic outcomes upon drug exposure.

Zinc-Dependent Regulation of ZEB1 and YAP1 Coactivation Promotes Epithelial-Mesenchymal Transition Plasticity and Metastasis in Pancreatic Cancer.

BACKGROUND: Pancreatic cancer is characterized by extensive metastasis. Epithelial-mesenchymal transition (EMT) plasticity plays a critical role in tumor progression and metastasis by maintaining the transition between EMT and mesenchymal-epithelial transition states. Our aim is to understand the molecular events regulating metastasis and EMT plasticity in pancreatic cancer. METHODS: The interactions between a cancer-promoting zinc transporter ZIP4, a zinc-dependent EMT transcriptional factor ZEB1, a coactivator YAP1, and integrin α3 (ITGA3) were examined in human pancreatic cancer cells, clinical specimens, spontaneous mouse models (KPC and KPCZ) and orthotopic xenografts, and 3-dimensional spheroid and organoid models. Correlations between ZIP4, miR-373, and its downstream targets were assessed by RNA in situ hybridization and immunohistochemical staining. The transcriptional regulation of ZEB1, YAP1, and ITGA3 by ZIP4 was determined by chromatin immunoprecipitation, co-immunoprecipitation, and luciferase reporter assays. RESULTS: The Hippo pathway effector YAP1 is a potent transcriptional coactivator and forms a complex with ZEB1 to activate ITGA3 transcription through the YAP1/transcriptional enhanced associate domain (TEAD) binding sites in human pancreatic cancer cells and KPC-derived mouse cells. ZIP4 upregulated YAP1 expression via activation of miR-373 and inhibition of the YAP1 repressor large tumor suppressor 2 kinase (LATS2). Furthermore, upregulation of ZIP4 promoted EMT plasticity, cell adhesion, spheroid formation, and organogenesis both in human pancreatic cancer cells, 3-dimensional spheroid model, xenograft model, and spontaneous mouse models (KPC and KPCZ) through ZEB1/YAP1-ITGA3 signaling axis. CONCLUSION: We demonstrated that ZIP4 activates ZEB1 and YAP1 through distinct mechanisms. The ZIP4-miR-373-LATS2-ZEB1/YAP1-ITGA3 signaling axis has a significant impact on pancreatic cancer metastasis and EMT plasticity.

Successful kidney transplantation in a patient with neonatal-onset ILNEB.

BACKGROUND: ILNEB constitute an autosomal recessive disorder caused by homozygous or compound heterozygous mutation of the gene for the ITGA3. To date, 8 ILNEB patients have been reported, but all 6 neonatal-onset ILNEB patients suffered early death within 2 years. The most common cause of death among previously reported ILNEB patients was exacerbation of the respiratory condition. METHODS: In this study, we describe a case of ILNEB with neonatal onset in a female patient and the genetic and histopathological testing performed. RESULTS: Our patient had a compound heterozygous mutation in ITGA3. Compared to previously reported patients, this patient exhibited milder clinical and histopathological characteristics. After experiencing a life-threatening respiratory infection at 8 months old, the patient started periodic subcutaneous immunoglobulin treatment once every 1-2 weeks for nephrotic-range proteinuria-induced secondary hypogammaglobulinemia. At the age of 3 years, proteinuria gradually increased with severe edema despite strict internal management. Therefore, our patient underwent unilateral nephrectomy and insertion of a peritoneal dialysis catheter followed by another unilateral nephrectomy. One month later, she underwent an ABO-compatible living-donor kidney transplantation at the age of 4 years. CONCLUSIONS: Our patient is a neonatal-onset ILNEB patient who survived for more than 2 years and underwent successful kidney transplantation.

TMT-Based Quantitative Proteomic Analysis Identification of Integrin Alpha 3 and Integrin Alpha 5 as Novel Biomarkers in Pathogenesis of Acute Aortic Dissection.

BACKGROUND: Acute aortic dissection (AAD) is a devastating cardiovascular disease with a high rate of disability and mortality. This disease often rapidly progresses to fatal multiple organ hypoperfusion, and the incidence has been increasing in recent years. However, the molecular mechanisms have yet to be clarified. This study is aimed at identifying the differential abundance proteins (DAPs) of aortic arch tissues in patients with AAD by proteomics and select possible proteins involved in AAD pathogenesis. METHODS: The fresh aortic arch tissues obtained from 5 AAD patients and 1 healthy donor were analyzed by amine-reactive tandem mass tag (TMT) labelling and mass spectrometry; then, the pathological sections of another 10 healthy donors and 20 AAD patients were chosen to verify the proteomic results by immunohistochemistry. RESULTS: Of 809 proteins identified by proteomic analysis, 132 differential abundance proteins (DAPs) were screened, of which 100 proteins were significantly downregulated while 32 upregulated. Among 100 downregulated proteins, two proteins with known function, integrin alpha 3 (ITGA-3) and ITGA-5, were selected as target proteins involved in AAD pathogenesis. Two target DAPs were verified by immunohistochemisty, and the results showed that the integrated option density (IOD) of ITGA-3 and ITGA-5 in AAD patients was significantly lower than that in healthy donors, which were consistent with the proteomic results (P < 0.001). CONCLUSION: ITGA-3 and ITGA-5 represent novel biomarkers for the pathogenesis of AAD and might be a therapeutic target in the future.

Interference with circBC048201 inhibits the proliferation, migration, and invasion of bladder cancer cells through the miR-1184/ITGA3 axis.

The abnormal expression of circular RNA (circRNA) is bound up with the progress of various human cancers. This study aimed to reveal the potential role and mechanism of circBC048201 in the proliferation, migration, and invasion of bladder cancer cells. Quantitative real-time PCR was performed to detect the expression of circBC048201. Cell Counting Kit-8, colony formation, and transwell migration and invasion assays were used to confirm the in vitro functions of circBC048201. Western blot, RNA pull-down, and dual-luciferase reporter gene experiments were performed to study the potential mechanism. circBC048201 was abnormally highly expressed in bladder cancer tissues and cells, and the interference with circBC048201 inhibited bladder cancer cell proliferation, migration, and invasion. From the potential mechanism analysis, our data suggested that circBC048201 and miR-1184, miR-1184 and ITGA3 could bind to each other, and the interference with circBC048201 repressed bladder cancer cell proliferation, migration, and invasion through the miR-1184/ITGA3 axis. In summary, our results showed that circBC048201 was abnormally highly expressed in bladder cancer tissues and cells, and the interference with circBC048201 inhibited the proliferation, migration, and invasion of bladder cancer cells through the miR-1184/ITGA3 axis.

MicroRNA­199a­5p suppresses cell proliferation, migration and invasion by targeting ITGA3 in colorectal cancer.

As a member of the integrin family, integrin α3ß1 (ITGA3) has been linked to intercellular communication and serves an important role in the signaling among cells and the extracellular matrix. MicroRNA (miR)­199a­5p has been demonstrated to be related to the pathogenesis and progression of multiple malignant diseases. However, the biological functions of miR­199a­5p and ITGA3 in colorectal cancer (CRC) have rarely been reported. The aim of the present study was to explore the roles of miR­199a­5p and ITGA3 in CRC. Immunohistochemistry staining and western blotting were applied to detect the protein expression of ITGA3 in CRC tissues and cells. Reverse transcription­quantitative PCR was performed to investigate the expression of miR­199a­5p and ITGA3 mRNA. HCT­116 cells were transfected with miR­199a­5p mimics, mimics control, short hairpin RNA targeting ITGA3, or pcDNA­ITGA3 for the functional experiments. Dual luciferase reporter assay was applied to confirm whether miR­199a­5p targeted the 3' untranslated region (3'UTR) of ITGA3. The MTT, Transwell and wound healing assays were used to evaluate the proliferation, invasion and migration of CRC cells. Immunofluorescence assay was used to monitor the epithelial­mesenchymal transition (EMT) biomarker expression. The results demonstrated downregulation of miR­199a­5p and upregulation of ITGA3 in CRC tissues and cell lines. miR­199a­5p mimics and knockdown of ITGA3 suppressed the proliferation, invasion and migration of CRC cells. Bioinformatics analysis and luciferase reporter assay indicated that miR­199a­5p targeted the 3'UTR of the ITGA3 transcript, and overexpression of ITGA3 reversed the tumor­suppressive effects of miR­199a­5p elevation. In addition, the immunofluorescence assay suggested that miR­199a­5p mimics suppressed the EMT of CRC cells, whereas the overexpression of ITGA3 restored this effect. In conclusion, miR­199a­5p may act as a tumor suppressor by targeting and negatively regulating ITGA3 in CRC.

Anatomy of a viral entry platform differentially functionalized by integrins α3 and α6.

During cell invasion, human papillomaviruses use large CD151 patches on the cell surface. Here, we studied whether these patches are defined architectures with features for virus binding and/or internalization. Super-resolution microscopy reveals that the patches are assemblies of closely associated nanoclusters of CD151, integrin α3 and integrin α6. Integrin α6 is required for virus attachment and integrin α3 for endocytosis. We propose that CD151 organizes viral entry platforms with different types of integrin clusters for different functionalities. Since numerous viruses use tetraspanin patches, we speculate that this building principle is a blueprint for cell-surface architectures utilized by viral particles.

Delayed Presentation of Respiratory Symptoms and Prolonged Survival in Homozygous a3 Integrin Deficiency.

Interstitial lung disease with nephrotic syndrome and junctional epidermolysis bullosa is caused by biallelic mutations in the integrin gene ITGA3 and is associated with death in infancy. We describe a variant of this syndrome with delayed presentation of symptoms and prolonged survival.

Iron oxides nanoparticles (IOs) exposed to magnetic field promote expression of osteogenic markers in osteoblasts through integrin alpha-3 (INTa-3) activation, inhibits osteoclasts activity and exerts anti-inflammatory action.

BACKGROUND: Prevalence of osteoporosis is rapidly growing and so searching for novel therapeutics. Yet, there is no drug on the market available to modulate osteoclasts and osteoblasts activity simultaneously. Thus in presented research we decided to fabricate nanocomposite able to: (i) enhance osteogenic differentiation of osteoblast, (i) reduce osteoclasts activity and (iii) reduce pro-inflammatory microenvironment. As a consequence we expect that fabricated material will be able to inhibit bone loss during osteoporosis. RESULTS: The α-Fe2O3/γ-Fe2O3 nanocomposite (IOs) was prepared using the modified sol-gel method. The structural properties, size, morphology and Zeta-potential of the particles were studied by means of XRPD (X-ray powder diffraction), SEM (Scanning Electron Microscopy), PALS and DLS techniques. The identification of both phases was checked by the use of Raman spectroscopy and Mössbauer measurement. Moreover, the magnetic properties of the obtained IOs nanoparticles were determined. Then biological properties of material were investigated with osteoblast (MC3T3), osteoclasts (4B12) and macrophages (RAW 264.7) in the presence or absence of magnetic field, using confocal microscope, RT-qPCR, western blot and cell analyser. Here we have found that fabricated IOs: (i) do not elicit immune response; (ii) reduce inflammation; (iii) enhance osteogenic differentiation of osteoblasts; (iv) modulates integrin expression and (v) triggers apoptosis of osteoclasts. CONCLUSION: Fabricated by our group α-Fe2O3/γ-Fe2O3 nanocomposite may become an justified and effective therapeutic intervention during osteoporosis treatment.