Association analysis for SNPs of LIPE and ITGB4 genes with cashmere production performance, body measurement traits and milk production traits in Liaoning cashmere goats

Liaoning cashmere goat (LCG) is one of the excellent cashmere goat breeds in China. Because of its larger size, better cashmere, and better cashmere production performance, people pay special attention to it. This article mainly studied the relationship between SNP loci of LIPE gene and ITGB4 gene and milk production, cashmere production and body measurement traits of LCGs. We further identified potential SNP loci by PCR-Seq polymorphism detection and gene sequence comparison of LIPE and ITGB4 genes. Further, we use SPSS and SHEsis software to analyze their relationship to production performance. The consequence indicated that CC genotype of LIPE gene T16409C locus was dominant genotype in milk production and cashmere production, while CT genotype of LIPE gene T16409C locus was dominant in body size. The CT genotype of C168T locus of ITGB4 gene is the dominant genotype of body type and cashmere production, while the dominant genotype of milk production is TT genotype. Through joint analysis, in haploid combinations, H1H2:CCCT is the dominant haplotype combination in cashmere fineness. H3H4:TTCT is a dominant haplotype combination of milk production traits and body measurement traits. These dominant genotypes can provide a reliable basis for the study of production performance of LCG.

The Interplay between Integrins and Immune Cells as a Regulator in Cancer Immunology

Integrins are a group of heterodimers consisting of α and β subunits that mediate a variety of physiological activities of immune cells, including cell migration, adhesion, proliferation, survival, and immunotolerance. Multiple types of integrins act differently on the same immune cells, while the same integrin may exert various effects on different immune cells. In the development of cancer, integrins are involved in the regulation of cancer cell proliferation, invasion, migration, and angiogenesis; conversely, integrins promote immune cell aggregation to mediate the elimination of tumors. The important roles of integrins in cancer progression have provided valuable clues for the diagnosis and targeted treatment of cancer. Furthermore, many integrin inhibitors have been investigated in clinical trials to explore effective regimens and reduce side effects. Due to the complexity of the mechanism of integrin-mediated cancer progression, challenges remain in the research and development of cancer immunotherapies (CITs). This review enumerates the effects of integrins on four types of immune cells and the potential mechanisms involved in the progression of cancer, which will provide ideas for more optimal CIT in the future.

Targeting integrin pathways: mechanisms and advances in therapy

Integrins are considered the main cell-adhesion transmembrane receptors that play multifaceted roles as extracellular matrix (ECM)-cytoskeletal linkers and transducers in biochemical and mechanical signals between cells and their environment in a wide range of states in health and diseases. Integrin functions are dependable on a delicate balance between active and inactive status via multiple mechanisms, including protein-protein interactions, conformational changes, and trafficking. Due to their exposure on the cell surface and sensitivity to the molecular blockade, integrins have been investigated as pharmacological targets for nearly 40 years, but given the complexity of integrins and sometimes opposite characteristics, targeting integrin therapeutics has been a challenge. To date, only seven drugs targeting integrins have been successfully marketed, including abciximab, eptifibatide, tirofiban, natalizumab, vedolizumab, lifitegrast, and carotegrast. Currently, there are approximately 90 kinds of integrin-based therapeutic drugs or imaging agents in clinical studies, including small molecules, antibodies, synthetic mimic peptides, antibody-drug conjugates (ADCs), chimeric antigen receptor (CAR) T-cell therapy, imaging agents, etc. A serious lesson from past integrin drug discovery and research efforts is that successes rely on both a deep understanding of integrin-regulatory mechanisms and unmet clinical needs. Herein, we provide a systematic and complete review of all integrin family members and integrin-mediated downstream signal transduction to highlight ongoing efforts to develop new therapies/diagnoses from bench to clinic. In addition, we further discuss the trend of drug development, how to improve the success rate of clinical trials targeting integrin therapies, and the key points for clinical research, basic research, and translational research.

Regulation of Kinase Signaling Pathways by α6β4-Integrins and Plectin in Prostate Cancer

Hemidesmosomes (HDs) are adhesive structures that ensure stable anchorage of cells to the basement membrane. They are formed by α6β4-integrin heterodimers and linked to intermediate filaments via plectin. It has been reported that one of the most common events during the pathogenesis of prostate cancer (PCa) is the loss of HD organization. While the expression levels of β4-integrins are strongly reduced, the expression levels of α6-integrins and plectin are maintained or even elevated, and seem to promote tumorigenic properties of PCa cells, such as proliferation, invasion, metastasis, apoptosis- and drug-resistance. In this review, we discuss the potential mechanisms of how HD components might contribute to various cellular signaling pathways to promote prostate carcinogenesis. Moreover, we summarize the current knowledge on the involvement of α6β4-integrins and plectin in PCa initiation and progression.

Lack of NPR1 Increases Vascular Endothelial Adhesion through Induction of Integrin Beta 4

Natriuretic peptide receptor 1 (NPR1) serves as a modulator of vascular endothelial homeostasis. Interactions between monocytes and endothelial cells may initiate endothelium dysfunction, which is known as an early hallmark of atherosclerosis. In this study, we performed RNA-sequencing analysis for the aorta of Npr1 knockout (Npr1^+/−) mice and found that differentially expressed genes were significantly related to cell adhesion. This result was supported by an increased expression of intercellular adhesion molecule 1 (ICAM-1) in the aortic endothelium of Npr1^+/− mice. Moreover, we observed that the knockdown of NPR1 increased ICAM-1 expression and promoted THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs). NPR1 overexpression decreased ICAM-1 expression and inhibited the adhesion of monocytes to HUVECs treated by TNF-α (a cell adhesion inducer). Further analysis showed that adhesion-related genes were enriched in the focal adhesion signaling pathway, in which integrin beta 4 (Itgb4) was determined as a key gene. Notably, ITGB4 expression increased in vascular endothelium of Npr1^+/− mice and in NPR1-knockdown HUVECs. The deficiency of ITGB4 decreased ICAM-1 expression and attenuated monocyte adhesion to NPR1-knockdown endothelial cells. Additionally, a reduced NPR1 and an increased ITGB4 expression level were found in an atherosclerosis mouse model. In conclusion, our findings demonstrate that NPR1 deficiency increases vascular endothelial cell adhesion by stimulating ITGB4 expression, which may contribute to the development of atherosclerosis.

Annexin A Protein Family in Atherosclerosis

Atherosclerosis, a silent chronic vascular pathology, is the cause of the majority of cardiovascular ischaemic events. Atherosclerosis is characterized by a series of deleterious changes in cellularity, including endothelial dysfunction, transmigration of circulating inflammatory cells into the arterial wall, pro-inflammatory cytokines production, lipid accumulation in the intima, vascular local inflammatory response, atherosclerosis-related cells apoptosis and autophagy. Proteins of Annexin A (AnxA) family, the well-known Ca²⁺ phospholipid-binding protein, have many functions in regulating inflammation-related enzymes and cell signaling transduction, thus influencing cell adhesion, migration, differentiation, proliferation and apoptosis. There is now accumulating evidence that some members of the AnxA family, such as AnxA1, AnxA2, AnxA5 and AnxA7, play major roles in the development of atherosclerosis. This article discusses the major roles of AnxA1, AnxA2, AnxA5 and AnxA7, and the multifaceted mechanisms of the main biological process in which they are involved in atherosclerosis. Considering these evidences, it has been proposed that AnxA are drivers- and not merely participator- on the road to atherosclerosis, thus the progression of atherosclerosis may be prevented by targeting the expression or function of the AnxA family proteins.

Prostate-Specific Membrane Antigen (PSMA) Promotes Angiogenesis of Glioblastoma Through Interacting With ITGB4 and Regulating NF-κB Signaling Pathway

Background

Glioblastoma multiforme (GBM) is the most common primary malignant tumor in the central nervous system (CNS), causing the extremely poor prognosis. Combining the role of angiogenesis in tumor progression and the role of prostate-specific membrane antigen (PSMA) in angiogenesis, this study aims to explore the functions of PSMA in GBM.

Methods

Clinical GBM specimens were collected from 60 patients who accepted surgical treatment in Fudan University Shanghai Cancer Center between January 2018 and June 2019. Immunohistochemical staining was used to detect PSMA and CD31 expression in GBM tissues. Prognostic significance of PSMA was evaluated by bioinformatics. Human umbilical vein endothelial cells (HUVECs) transfected with PSMA overexpression plasmids or cultured with conditioned medium collected based on GBM cells, were used for CCK8, Transwell and tube formation assays. High-throughput sequencing and immunoprecipitation were used to explore the underlying mechanism. Furthermore, the in vivo experiment had been also conducted.

Results

We demonstrated that PSMA was abundantly expressed in endothelium of vessels of GBM tissues but not in vessels of normal tissues, which was significantly correlated with poor prognosis. Overexpression of PSMA could promotes proliferation, invasion and tube formation ability of human umbilical vein endothelial cells (HUVECs). Moreover, U87 or U251 conditioned medium could upregulated PSMA expression and induce similar effects on phenotypes of HUVECs, all of which could be partially attenuated by 2-PMPA treatment. The mechanistic study revealed that PSMA might promote angiogenesis of GBM through interacting with Integrin β4 (ITGB4) and activating NF-κB signaling pathway. The in vivo growth of GBM could be alleviated by the treatment of 2-PMPA.

Conclusion

This study identified PSMA as a critical regulator in angiogenesis and progression of GBM, which might be a promising therapeutic target for GBM treatment.

Interplay between Cell-Surface Receptors and Extracellular Matrix in Skin

Skin consists of the epidermis and dermis, which are connected by a specialized basement membrane-the epidermal basement membrane. Both the epidermal basement membrane and the underlying interstitial extracellular matrix (ECM) created by dermal fibroblasts contain distinct network-forming macromolecules. These matrices play various roles in order to maintain skin homeostasis and integrity. Within this complex interplay of cells and matrices, cell surface receptors play essential roles not only for inside-out and outside-in signaling, but also for establishing mechanical and biochemical properties of skin. Already minor modulations of this multifactorial cross-talk can lead to severe and systemic diseases. In this review, major epidermal and dermal cell surface receptors will be addressed with respect to their interactions with matrix components as well as their roles in fibrotic, inflammatory or tumorigenic skin diseases.

Roles of Annexin A protein family in autophagy regulation and therapy

Annexin A is a kind of calcium-dependent phospholipid-binding proteins, which contributes to the formation of the cell membranes and cytoskeleton and played a part as a membrane skeleton to stabilize lipid bilayer. Autophagy is one of the most important programmed cell death mechanisms. And recently some reports suggest that annexin A family protein is associated with autophagy for annexin A can regulate the formation of vesicular lipid membranes and promote cell exocytosis. In this review, we summarized the roles of annexin A protein family in autophagy regulation and targeted medical treatment for better diagnoses and therapies.

Integrin: Basement membrane adhesion by corneal epithelial and endothelial cells

Integrins mediate adhesion of cells to substrates and maintain tissue integrity by facilitating mechanotransduction between cells, the extracellular matrix, and gene expression in the nucleus. Changes in integrin expression in corneal epithelial cells and corneal endothelial cells impacts their adhesion to the epithelial basement membrane (EpBM) and Descemet's membrane, respectively. Integrins also play roles in assembly of basement membranes by both activating TGFβ1 and other growth factors. Over the past two decades, this knowledge has been translated into methods to grow corneal epithelial and endothelial cells in vitro for transplantation in the clinic thereby transforming clinical practice and quality of life for patients. Current knowledge on the expression and function of the integrins that mediate adhesion to the basement membrane expressed by corneal epithelial and endothelial cells in health and disease is summarized. This is the first review to discuss similarities and differences in the integrins expressed by both cell types.

Astrocytes increase exosomal secretion of oligodendrocyte precursor cells to promote their proliferation via integrin β4-mediated cell adhesion

Many degenerative diseases of the central nervous system (CNS) are associated with demyelination. Oligodendrocyte precursor cells (OPCs) are potential stem cells that can differentiate into oligodendrocytes (OLs) and promote myelination. Promoting the proliferation of OPCs is key to stimulating remyelination and treating neurodegenerative diseases. Herein, we report that astrocytes (ASTs) could increase exosomal secretion of OPCs to promote their proliferation via ITGB4-mediated cell adhesion. Our results demonstrate that ASTs can regulate the proliferation of OPCs through ITGB4-mediated exosomal secretion. OPC proliferation is significantly increased after direct-contact culture with ASTs. Gene ontology (GO) and KEGG pathway analyses reveal that ITGB4/extracellular exosome are closely related to OPC proliferation. siRNA ITGB4 decreases exosomal secretion and OPC proliferation. ITGB4/exosomes remarkably promote OPC transition from G1 to S phase. Furthermore, exosomes can alleviate the inhibitory effect of ITGB4 knockdown on OPC proliferation. Collectively, ASTs regulate OPC exosomal secretion via ITGB4, which could be a valuable approach for promoting OPC proliferation. This strategy may represent a potential treatment for neurological diseases caused by demyelination.

Integrin beta 4 (ITGB4) and its tyrosine-1510 phosphorylation promote pancreatic tumorigenesis and regulate the MEK1-ERK1/2 signaling pathway

Pancreatic cancer is the fourth leading cause of cancer death, with a 5-year survival rate of only 1–4%. Integrin-mediated cell adhesion is critical for the initiation, progression, and metastasis of cancer. In this study we investigated the role of integrin β4 (ITGB4) and its phosphorylation at tyrosine Y1510 (p-ITGB4-Y1510) in the tumorigenesis of pancreatic cancer. We analyzed the expression of ITGB4 and p-ITGB4-Y1510 in pancreatic cancer tissue and cell lines using immunohistochemistry, Western blot, or semi-quantitative reverse transcription PCR. ITGB4 and p-ITGB4-Y1510 were highly expressed in pancreatic cancer (n = 176) compared with normal pancreatic tissue (n = 171). High p-ITGB4-Y1510 expression correlated with local invasion and distant metastasis of pancreatic cancer, and high ITGB4 was significantly associated with poor survival of patients. Inhibition of ITGB4 by siRNA significantly reduced migration and invasion of PC-1.0 and AsPC-1 cells. Overexpression of the mutant ITGB4-Y1510A (a mutation of tyrosine to alanine at 1510 position) in PC-1.0 and AsPC-1 cells not only blocked the ITGB4 phosphorylation at Y1510 but also suppressed the expression of ITGB4 (p < 0.05 vs. wild-type ITGB4). The transfection of PC-1.0 and AsPC-1 cells with ITGB4-Y1510A significantly decreased the level of p-mitogen-activated protein kinase kinase (MEK)1 (T292) and p-extracellular signal-regulated kinase (ERK)1/2 but did not affect the level of p-MEK1 (T386) and p-MEK2 (T394). Overall, our study showed that ITGB4 and its phosphorylated form promote cell migration and invasion in pancreatic cancer and that p-ITGB4-Y1510 regulates the downstream MEK1-ERK1/2 signaling cascades. Targeting ITGB4 or its phosphorylation at Y1510 may be a novel therapeutic option for pancreatic cancer.

Comparative omics of CCM signaling complex (CSC)

BACKGROUND

Cerebral cavernous malformations (CCMs), a major neurosurgical condition, characterized by abnormally dilated intracranial capillaries, result in increased susceptibility to stroke. KRIT1 (CCM1), MGC4607 (CCM2), and PDCD10 (CCM3) have been identified as causes of CCMs in which at least one of them is disrupted in most familial cases. Our goal is to identify potential biomarkers and genetic modifiers of CCMs, using a global comparative omics approach across several in vitro studies and multiple in vivo animal models. We hypothesize that through analysis of the CSC utilizing various omics, we can identify potential biomarkers and genetic modifiers, by systemically evaluating effectors and binding partners of the CSC as well as second layer interactors.

METHODS

We utilize a comparative omics approach analyzing multiple CCMs deficient animal models across nine independent studies at the genomic, transcriptomic, and proteomic levels to dissect alterations in various signaling cascades.

RESULTS

Our analysis revealed a large set of genes that were validated across multiple independent studies, suggesting an important role for these identified genes in CCM pathogenesis.

CONCLUSION

This is currently one of the largest comparative omics analysis of CCM deficiencies across multiple models, allowing us to investigate global alterations among multiple signaling cascades involved in both angiogenic and non-angiogenic events and to also identify potential biomarker candidates of CCMs, which can be used for new therapeutic strategies.

Expression and prognostic analyses of ITGA11, ITGB4 and ITGB8 in human non-small cell lung cancer

Background

Integrins play a crucial role in the regulation process of cell proliferation, migration, differentiation, tumor invasion and metastasis. ITGA11, ITGB4 and ITGB8 are three encoding genes of integrins family. Accumulative evidences have proved that abnormal expression of ITGA11, ITGB4 and ITGB8 are a common phenomenon in different malignances. However, their expression patterns and prognostic roles for patients with non-small cell lung cancer (NSCLC) have not been completely illustrated.

Methods

We investigated the expression patterns and prognostic values of ITGA11, ITGB4 and ITGB8 in patients with NSCLC through using a series of databases and various datasets, including ONCOMINE, GEPIA, HPA, TCGA and GEO datasets.

Results

We found that the expression levels of ITGA11 and ITGB4 were significantly upregulated in both LUAD and LUSC, while ITGB8 was obviously upregulated in LUSC. Additionally, higher expression level of ITGB4 revealed a worse OS in LUAD.

Conclusion

Our findings suggested that ITGA11 and ITGB4 might have the potential ability to act as diagnostic biomarkers for both LUAD and LUSC, while ITGB8 might serve as diagnostic biomarker for LUSC. Furthermore, ITGB4 could serve as a potential prognostic biomarker for LUAD.

Systems-wide analysis unravels the new roles of CCM signal complex (CSC)

Cerebral cavernous malformations (CCMs) are characterized by abnormally dilated intracranial capillaries that result in increased susceptibility to stroke. Three genes have been identified as causes of CCMs; KRIT1 (CCM1), MGC4607 (CCM2) and PDCD10 (CCM3); one of them is disrupted in most CCM cases. It was demonstrated that both CCM1 and CCM3 bind to CCM2 to form a CCM signaling complex (CSC) to modulate angiogenesis. In this report, we deployed both RNA-seq and proteomic analysis of perturbed CSC after depletion of one of three CCM genes to generate interactomes for system-wide studies. Our results demonstrated a unique portrait detailing alterations in angiogenesis and vascular integrity. Interestingly, only in-direct overlapped alterations between RNA and protein levels were detected, supporting the existence of multiple layers of regulation in CSC cascades. Notably, this is the first report identifying that both β4 integrin and CAV1 signaling are downstream of CSC, conveying the angiogenic signaling. Our results provide a global view of signal transduction modulated by the CSC, identifies novel regulatory signaling networks and key cellular factors associated with CSC.

Identification and characterization of a murine model of BCR‑ABL1+ acute B‑lymphoblastic leukemia with central nervous system metastasis

Breakpoint cluster region (BCR)-Abelson murine leukemia (ABL)1⁺ acute B-lymphoblastic leukemia (B-ALL) is a disease associated with a dismal prognosis and a high incidence of central nervous system (CNS) metastasis. However, BCR-ABL1⁺ B-ALL with CNS infiltration has not been previously characterized, at least to the best of our knowledge. In the present study, a murine model of BCR-ABL1⁺ B-ALL with CNS metastasis was established using retroviral transduction. The vast majority of BCR-ABL1⁺ leukemic cells were found to be immature B cells with a variable proportion of pro-B and pre-B populations. The present results indicated that the BCR-ABL1⁺ B-leukemic cells expressed high levels integrin subunit alpha 6 (Itga6) and L-selectin adhesion molecules, and have an intrinsic ability to disseminate and accumulate in CNS tissues, predominantly in meninges. On the whole, these results provide an approach for addressing the mechanisms of BCR-ABL1⁺ B-ALL with CNS metastasis and may guide the development of novel therapeutic strategies.

ITGB4 deficiency induces senescence of airway epithelial cells through p53 activation

Aging is characterized by a progressive loss of physiological integrity, leading to impaired organ function and, ultimately, increased vulnerability to death. Many complex diseases are related to aging, including asthma. In the lung, the airway epithelium serves as the first barrier to prevent the access of inspired external stimuli and dictates the initial stress responses. Notably, in the airway mucosa of asthma patients, an increase in senescent airway epithelial cells has been detected. Although it has been speculated that the senescence of airway epithelial cells could increase asthma susceptibility and aggravate asthma severity, the role of cell senescence in the development of asthma remains unclear. Integrin β4 (ITGB4) is a structural adhesion molecule with complex physiological functions that is downregulated in airway epithelial cells of asthma patients. This study demonstrates that the expression of ITGB4 in airway epithelial cells is downregulated significantly under oxidative stress or upon inflammatory stimulation. Moreover, we show that ITGB4 deficiency induces the senescence of airway epithelial cells through the activation of the p53 pathway both in vitro and in vivo. Together, our results demonstrate that airway epithelial senescence induced by ITGB4 deficiency after oxidative stress or inflammatory stimulation may be involved in the pathogenesis of asthma. Understanding the contribution of ITGB4 deficiency to the senescence of airway epithelial cells in asthma patients may provide new therapeutic approaches for the treatment of asthma.

Reciprocal regulation of integrin β4 and KLF4 promotes gliomagenesis through maintaining cancer stem cell traits

BACKGROUND

The dismal prognosis of patients with glioma is largely attributed to cancer stem cells that display pivotal roles in tumour initiation, progression, metastasis, resistance to therapy, and relapse. Therefore, understanding how these populations of cells maintain their stem-like properties is critical in developing effective glioma therapeutics.

METHODS

RNA sequencing analysis was used to identify genes potentially involved in regulating glioma stem cells (GSCs). Integrin β4 (ITGB4) expression was validated by quantitative real-time PCR (qRT-PCR) and immunohistochemical (IHC) staining. The role of ITGB4 was investigated by flow cytometry, mammosphere formation, transwell, colony formation, and in vivo tumorigenesis assays. The reciprocal regulation between Integrin β4 and KLF4 was investigated by chromatin immunoprecipitation (ChIP), dual-luciferase reporter assay, immunoprecipitation, and in vivo ubiquitylation assays.

RESULTS

In this study, we found that ITGB4 expression was increased in GSCs and human glioma tissues. Upregulation of ITGB4 was correlated with glioma grades. Inhibition of ITGB4 in glioma cells decreased the self-renewal abilities of GSCs and suppressed the malignant behaviours of glioma cells in vitro and in vivo. Further mechanistic studies revealed that KLF4, an important transcription factor, directly binds to the promoter of ITGB4, facilitating its transcription and contributing to increased ITGB4 expression in glioma. Interestingly, this increased expression enabled ITGB4 to bind KLF4, thus attenuating its interaction with its E3 ligase, the von Hippel-Lindau (VHL) protein, which subsequently decreases KLF4 ubiquitination and leads to its accumulation.

CONCLUSIONS

Collectively, our data indicate the existence of a positive feedback loop between KLF4 and ITGB4 that promotes GSC self-renewal and gliomagenesis, suggesting that ITGB4 may be a valuable therapeutic target for glioma.

Ping-Pong-Tumor and Host in Pancreatic Cancer Progression

Metastasis is the main cause of high pancreatic cancer (PaCa) mortality and trials dampening PaCa mortality rates are not satisfying. Tumor progression is driven by the crosstalk between tumor cells, predominantly cancer-initiating cells (CIC), and surrounding cells and tissues as well as distant organs, where tumor-derived extracellular vesicles (TEX) are of major importance. A strong stroma reaction, recruitment of immunosuppressive leukocytes, perineural invasion, and early spread toward the peritoneal cavity, liver, and lung are shared with several epithelial cell-derived cancer, but are most prominent in PaCa. Here, we report on the state of knowledge on the PaCIC markers Tspan8, alpha6beta4, CD44v6, CXCR4, LRP5/6, LRG5, claudin7, EpCAM, and CD133, which all, but at different steps, are engaged in the metastatic cascade, frequently via PaCIC-TEX. This includes the contribution of PaCIC markers to TEX biogenesis, targeting, and uptake. We then discuss PaCa-selective features, where feedback loops between stromal elements and tumor cells, including distorted transcription, signal transduction, and metabolic shifts, establish vicious circles. For the latter particularly pancreatic stellate cells (PSC) are responsible, furnishing PaCa to cope with poor angiogenesis-promoted hypoxia by metabolic shifts and direct nutrient transfer via vesicles. Furthermore, nerves including Schwann cells deliver a large range of tumor cell attracting factors and Schwann cells additionally support PaCa cell survival by signaling receptor binding. PSC, tumor-associated macrophages, and components of the dysplastic stroma contribute to perineural invasion with signaling pathway activation including the cholinergic system. Last, PaCa aggressiveness is strongly assisted by the immune system. Although rich in immune cells, only immunosuppressive cells and factors are recovered in proximity to tumor cells and hamper effector immune cells entering the tumor stroma. Besides a paucity of immunostimulatory factors and receptors, immunosuppressive cytokines, myeloid-derived suppressor cells, regulatory T-cells, and M2 macrophages as well as PSC actively inhibit effector cell activation. This accounts for NK cells of the non-adaptive and cytotoxic T-cells of the adaptive immune system. We anticipate further deciphering the molecular background of these recently unraveled intermingled phenomena may turn most lethal PaCa into a curatively treatable disease.

Integrin-β4 is a novel transcriptional target of TAp73

As a member of p53 family, p73 has attracted intense investigations due to its structural and functional similarities to p53. Among more than ten p73 variants, the transactivation (TA) domain-containing isoform TAp73 is the one that imitates the p53's behavior most. TAp73 induces apoptosis and cell cycle arrest, which endows it the capacity of tumour suppression. Also, it can exert diverse biological influences on cells through activating a complex and context dependent transcriptional programme. The transcriptional activities further broaden its roles in more intricate biological processes. In this article, we report that p73 is a positive regulator of a cell adhesion related gene named integrin β4 (ITGB4). This finding may have implications for the dissection of the biological mechanisms underlining p73 functions.

Integrin β4 promotes cell invasion and epithelial-mesenchymal transition through the modulation of Slug expression in hepatocellular carcinoma

Integrin β4 (ITGB4) is a transmembrane receptor involved in tumorigenesis and the invasiveness of many cancers. However, its role in hepatocellular carcinoma (HCC), one of the most prevalent human cancers worldwide, remains unclear. Here, we examined the involvement of ITGB4 in HCC and explored the underlying mechanisms. Real-time PCR and immunohistochemical analyses of tissues from 82 patients with HCC and four HCC cell lines showed higher ITGB4 levels in tumor than in adjacent non-tumor tissues and in HCC than in normal hepatic cells. Silencing of ITGB4 repressed cell proliferation, colony forming ability and cell invasiveness, whereas ectopic expression of ITGB4 promoted the proliferation and invasion of HCC cells and induced epithelial to mesenchymal transition (EMT) in parallel with the upregulation of Slug, as shown by transwell assays, WB and immunocytochemistry. Knockdown of Slug reduced cell viability inhibited invasion and reversed the effects of ITBG4 overexpression on promoting EMT, and AKT/Sox2-Nanog may also be involved. In a xenograft tumor model induced by injection of ITGB4-overexpressing cells into nude mice, ITGB4 promoted tumor growth and metastasis to the lungs. Taken together, our results indicate that ITGB4 plays a tumorigenic and pro-metastatic role mediated by Slug and suggest IGTB4 could be a prognostic indicator or a therapeutic target in patients with HCC.

Identification of New Small Molecules as Apoptosis Inhibitors in Vascular Endothelial Cells

Vascular endothelial cell (VEC) apoptosis is involved in the development of atherosclerosis and other cardiovascular diseases. We previously found that ethyl 1-(2-hydroxy-3-aroxypropyl)-3-aryl-1H-pyrazole -5-carboxylate derivatives (3a-o) play important roles in cell fate control. In this study, among the 15 compounds, we further screened 2 compounds, 3d and 3k, that suppressed VEC apoptosis induced by deprivation of serum and fibroblast growth factor 2. To clarify which chiral enantiomers of 3d and 3k functioned, we synthesized 3d-S and its enantiomer 3d-R, 3k-S, and its enantiomer 3k-R. Then, we investigated the apoptosis-inhibiting activity of the chiral compounds in VECs. Four small molecules, 3d-S, 3d-R, 3k-S, 3k-R, significantly elevated VEC viability and inhibited apoptosis. Furthermore, these small molecules could obviously decrease the level of integrin β4 that plays a key role in the regulation of VEC apoptosis. 3k-S and 3k-R increased Bcl-2/Bax ratio and reduced reactive oxygen species levels dramatically. Therefore, we provide new VEC apoptosis inhibitors. These compounds may be potential agents in the prevention of vascular diseases associated with VEC apoptosis.

The role of endoglin in post-ischemic revascularization

Following arterial occlusion, blood vessels respond by forming a new network of functional capillaries (angiogenesis), by reorganizing preexisting capillaries through the recruitment of smooth muscle cells to generate new arteries (arteriogenesis) and by growing and remodeling preexisting collateral arterioles into physiologically relevant arteries (collateral development). All these processes result in the recovery of organ perfusion. The importance of endoglin in post-occlusion reperfusion is sustained by several observations: (1) endoglin expression is increased in vessels showing active angiogenesis/remodeling; (2) genetic endoglin haploinsufficiency in humans causes deficient angiogenesis; and (3) the reduction of endoglin expression by gene disruption or the administration of endoglin-neutralizing antibodies reduces angiogenesis and revascularization. However, the precise role of endoglin in the several processes associated with revascularization has not been completely elucidated and, in some cases, the function ascribed to endoglin by different authors is controversial. The purpose of this review is to organize in a critical way the information available for the role of endoglin in several phenomena (angiogenesis, arteriogenesis and collateral development) associated with post-ischemic revascularization.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Insulin-like growth factor binding protein-3 inhibits cell adhesion via suppression of integrin β4 expression

We previously reported that IGF binding protein-3 (IGFBP-3), a major IGF-binding protein in human serum, regulates angiogenic activities of human head and neck squamous cell carcinoma (HNSCC) cells and human umbilical vein endothelial cells (HUVECs) through IGF-dependent and IGF-independent mechanisms. However, the role of IGFBP-3 in cell adhesion is largely unknown. We demonstrate here that IGFBP-3 inhibits the adhesion of HNSCC cells and HUVECs to the extracellular matrix (ECM). IGFBP-3 reduced transcription of a variety of integrins, especially integrin β₄, and suppressed phosphorylation of focal adhesion kinase (FAK) and Src in these cells through both IGF-dependent and IGF-independent pathways. IGFBP-3 was found to suppress the transcription of c-fos and c-jun and the activity of AP1 transcription factor. The regulatory effect of IGFBP-3 on integrin β₄ transcription was attenuated by blocking c-jun and c-fos gene expression via siRNA transfection. Taken together, our data show that IGFBP-3 has IGF-dependent and -independent inhibitory effects on intracellular adhesion signaling in HNSCC and HUVECs through its ability to block c-jun and c-fos transcription and thus AP-1-mediated integrin β₄ transcription. Collectively, our data suggest that IGFPB-3 may be an effective cancer therapeutic agent by blocking integrin-mediated adhesive activity of tumor and vascular endothelial cells.

Potential roles of annexin A7 GTPase in autophagy, senescence and apoptosis

This review covers the roles of ANXA7 GTPase in orchestrating autophagy, senescence and apoptosis interactive networks in various cell types.

Clinical significance of the integrin α6β4 in human malignancies

Integrin α6β4 is a cellular adhesion molecule that binds to laminins in the extracellular matrix and nucleates the formation of hemidesmosomes. During carcinoma progression, integrin α6β4 is released from hemidesmosomes, where it can then signal to facilitate multiple aspects of tumor progression including sustaining proliferative signaling, tumor invasion and metastasis, evasion of apoptosis, and stimulation of angiogenesis. The integrin achieves these ends by cooperating with growth factor receptors including EGFR, ErbB-2, and c-Met to amplify downstream pathways such as PI3K, AKT, MAPK, and the Rho family small GTPases. Furthermore, it dramatically alters the transcriptome toward a more invasive phenotype by controlling promoter DNA demethylation of invasion and metastasis-associated proteins, such as S100A4 and autotaxin, and upregulates and activates key tumor-promoting transcription factors such as the NFATs and NF-κB. Expression of integrin α6β4 has been studied in many human malignancies where its overexpression is associated with aggressive behavior and a poor prognosis. This review provides an assessment of integrin α6β4 expression patterns and their prognostic significance in human malignancies, and describes key signaling functions of integrin α6β4 that contribute to tumor progression.

Analysis on the relevance of asthma susceptibility with the alteration of integrin β 4 expression

Accumulated research has suggested the importance of the adhesion molecules modulation as therapeutic approach for bronchial asthma. Adhesion molecules expression alteration contributes to the pathogenesis of asthma. In order to probe the roles of expression imbalance of adhesion molecules in asthma pathogenesis, expression profiling of adhesion molecules was performed using cDNA microarray assay. The results showed that the expression pattern of adhesion molecules was altered in peripheral blood leucocytes of asthma patients. In this study, we focused on one of the abnormally expressed molecule, integrin β4, which was down-regulated in all asthma patients, to analyze the relevance of asthma susceptibility with the alteration of integrin β4 expressions. Real time PCR was used to verify the down-regulation of integrin β4 in additional 38 asthma patients. Next, the 5'flanking region of integrin β4 DNA were amplified, sequenced and site-directed mutagenesis technology in correspondent variation sites were carried out. Among 4 variation sites found in 5' flanking region of integrin β4, 3 were related to asthma susceptibility: -nt1029 G/A, -nt 1051 G/A, and -nt 1164 G/C. A reduction of human integrin β4 promoter activity was observed at mutants of these sites. This study demonstrates that various adhesion molecules in asthma patients are abnormally expressed. Mutations in 5' flanking region result in reduced integrin β4 expression, which is related to increased risk of asthma.

Phosphorylation and nuclear translocation of integrin β4 induced by a chemical small molecule contribute to apoptosis in vascular endothelial cells

Integrin β4 and its Y-1494 phosphorylation play an important role in cell signaling. We found a small molecule, ethyl1-(3-(4-chlorophenoxy)-2-hydroxypropyl)-3-(4-chlorophenyl)-1H-pyrazole-5-carboxylate (ECPC), that could elevate the levels of KIT ligand (KITLG), interleukin 8 (IL-8), prostaglandin-endoperoxide synthase 2 (PTGS2) and activating transcription factor 3 (ATF3) and promote apoptosis in vascular endothelial cells (VECs) through integrin β4. We investigated the underlying mechanism of integrin β4 participating in this process. ECPC treatment increased the phosphorylation of Y-1494 in the integrin β4 cytoplasmic domain via a well-known receptor tyrosine kinase, fibroblast growth factor receptor 1 (FGFR1), and integrin β4 translocated from the cytoplasm to nucleus. With suppression of Y-1494 phosphorylation by FGF-2 or siRNA of FGFR1, ECPC failed to promote integrin β4 nuclear translocation and could not increase the expression of KITLG, IL-8, PTGS2 or ATF3. Y-1494 phosphorylation and nuclear translocation of integrin β4 may be important during ECPC-induced apoptosis in VECs.

The role of integrins in the trabecular meshwork

Integrins are a family of heterodimeric transmembrane receptors that mediate adhesion to the extracellular matrix (ECM). However, integrins are not just adhesion receptors. They can act as "bidirectional signal transducers" that coordinate a large number of cellular activities in response to the extracellular environment and intracellular signaling events. Among the activities regulated by integrins are cell adhesion, assembly of the ECM, growth factor signaling, apoptosis, organization of the cytoskeleton, and cytoskeleton-mediated processes such as contraction, endocytosis, and phagocytosis. Integrins regulate these activities through a complex network of intracellular signaling kinases and adaptor proteins that associate with the transmembrane and cytoplasmic domains of the integrin subunits. In this review, we will discuss how some of the known integrin-mediated activities can control the function of the trabecular meshwork. We will also discuss how integrin activity is a tightly regulated process that involves conformation changes within the heterodimer which are mediated by specific integrin-binding proteins.

NETRIN-4 protects glioblastoma cells FROM temozolomide induced senescence

Glioblastoma multiforme is the most common primary tumor of the central nervous system. The drug temozolomide (TMZ) prolongs lifespan in many glioblastoma patients. The sensitivity of glioblastoma cells to TMZ is interfered by many factors, such as the expression of O-6-methylguanine-DNA methyltransferase (MGMT) and activation of AKT signaling. We have recently identified the interaction between netrin-4 (NTN4) and integrin beta-4 (ITGB4), which promotes glioblastoma cell proliferation via activating AKT-mTOR signaling pathway. In the current work we have explored the effect of NTN4/ITGB4 interaction on TMZ induced glioblastoma cell senescence. We report here that the suppression of either ITGB4 or NTN4 in glioblastoma cell lines significantly enhances cellular senescence. The sensitivity of GBM cells to TMZ was primarily determined by the expression of MGMT. To omit the effect of MGMT, we concentrated on the cell lines devoid of expression of MGMT. NTN4 partially inhibited TMZ induced cell senescence and rescued AKT from dephosphorylation in U251MG cells, a cell line bearing decent levels of ITGB4. However, addition of exogenous NTN4 displayed no significant effect on TMZ induced senescence rescue or AKT activation in U87MG cells, which expressed ITGB4 at low levels. Furthermore, overexpression of ITGB4 combined with exogenous NTN4 significantly attenuated U87MG cell senescence induced by TMZ. These data suggest that NTN4 protects glioblastoma cells from TMZ induced senescence, probably via rescuing TMZ triggered ITGB4 dependent AKT dephosphorylation. This suggests that interfering the interaction between NTN4 and ITGB4 or concomitant use of the inhibitors of the AKT pathway may improve the therapeutic efficiency of TMZ.