Defining the role of laminin-332 in carcinoma

Matrikines in the skin: Origin, effects, and therapeutic potential

The extracellular matrix (ECM) represents a complex multi-component environment that has a decisive influence on the biomechanical properties of tissues and organs. Depending on the tissue, ECM components are subject to a homeostasis of synthesis and degradation, a subtle interplay that is influenced by external factors and the intrinsic aging process and is often disturbed in pathologies. Upon proteolytic cleavage of ECM proteins, small bioactive peptides termed matrikines can be formed. These bioactive peptides play a crucial role in cell signaling and contribute to the dynamic regulation of both physiological and pathological processes such as tissue remodeling and repair as well as inflammatory responses. In the skin, matrikines exert an influence for instance on cell adhesion, migration, and proliferation as well as vasodilation, angiogenesis and protein expression. Due to their manifold functions, matrikines represent promising leads for developing new therapeutic options for the treatment of skin diseases. This review article gives a comprehensive overview on matrikines in the skin, including their origin in the dermal ECM, their biological effects and therapeutic potential for the treatment of skin pathologies such as melanoma, chronic wounds and inflammatory skin diseases or for their use in anti-aging cosmeceuticals.

Cell Junctions in Periodontal Health and Disease: An Insight

Cells are the building blocks of all living organisms. The presence of cell junctions such as tight junctions, gap junctions, and anchoring junctions between cells play a role in cell-to-cell communication in periodontal health and disease. A literature search was done in Scopus, PubMed, and Web of Science to gather information about the effect of cell junctions on periodontal health and disease. The presence of tight junction in the oral cavity helps in cell-to-cell adhesiveness and assists in the barrier function. The gap junctions help in controlling growth and development and in the cell signaling process. The presence of desmosomes and hemidesmosomes as anchoring junctions aid in mechanical strength and tissue integrity. Periodontitis is a biofilm-induced disease leading to the destruction of the supporting structures of the tooth. The structures of the periodontium possess multiple cell junctions that play a significant role in periodontal health and disease as well as periodontal tissue healing. This review article provides an insight into the role of cell junctions in periodontal disease and health, and offers concepts for development of therapeutic strategies through manipulation of cell junctions.

LAMC2 is a potential prognostic biomarker for cholangiocarcinoma

Cholangiocarcinoma is a common malignancy with increasing incidence worldwide. Most patients are diagnosed at the advanced stage with poor survival rate. Laminin subunit γ2 (LAMC2) is a heparin binding-associated gene involved in tumorigenesis and has been implicated in the prognosis of various types of cancers. However, it is unclear whether expression of LAMC2 is associated with the clinical outcome of patients with cholangiocarcinoma. In the present study, the role and prognostic value of LAMC2 expression in patients with cholangiocarcinoma was investigated. Clinical information and pathological characteristics were analyzed and the association between LAMC2 expression and clinical characteristics, pathological findings and patient outcomes, including metastasis-free and disease-specific survival, were investigated. Data from 182 patients with cholangiocarcinoma were evaluated. High LAMC2 expression was associated with higher tumor stage (P<0.001), large duct type (P=0.024) and poor histological grade (P=0.002). Kaplan-Meier analysis showed high LAMC2 expression was associated with lower overall (P=0.003), disease-specific (P=0.0025), local recurrence-free (P<0.0001) and metastasis-free survival (P<0.0001). Moreover, multivariate analysis demonstrated that increased LAMC2 expression was a significant predictive risk factor for overall [hazard ratio (HR) 1.713; P=0.034], disease-specific (HR 2.011; P=0.039), local recurrence-free (HR 2.721; P<0.001) and metastasis-free survival (HR 3.117; P<0.001). Gene enrichment analysis using Gene Ontology showed that terms associated with LAMC2 upregulation were 'regulation of platelet-derived growth factor receptor-βsignaling pathway' and 'platelet-derived growth factor receptor-β signaling pathway'. The present study indicated that LAMC2 was upregulated in cholangiocarcinoma tumor tissue and had an inverse association with overall, disease-specific, local recurrence-free and metastasis-free survival in patients with cholangiocarcinoma. These results suggested that LAMC2 may serve as a potential biomarker for cholangiocarcinoma.

Inhibition of TGF-β signaling, invasion, and growth of cutaneous squamous cell carcinoma by PLX8394

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer. The prognosis of patients with metastatic cSCC is poor emphasizing the need for new therapies. We have previously reported that the activation of Ras/MEK/ERK1/2 and transforming growth factor β (TGF-β)/Smad2 signaling in transformed keratinocytes and cSCC cells leads to increased accumulation of laminin-332 and accelerated invasion. Here, we show that the next-generation B-Raf inhibitor PLX8394 blocks TGF-β signaling in ras-transformed metastatic epidermal keratinocytes (RT3 cells) harboring wild-type B-Raf and hyperactive Ras. PLX8394 decreased phosphorylation of TGF-β receptor II and Smad2, as well as p38 activity, MMP-1 and MMP-13 synthesis, and laminin-332 accumulation. PLX8394 significantly inhibited the growth of human cSCC tumors and in vivo collagen degradation in xenograft model. In conclusion, our data indicate that PLX8394 inhibits several serine-threonine kinases in malignantly transformed human keratinocytes and cSCC cells and inhibits cSCC invasion and tumor growth in vitro and in vivo. We identify PLX8394 as a potential therapeutic compound for advanced human cSCC.

Paraneoplastic autoimmune Laminin-332 syndrome (PALS): Anti-Laminin-332 mucous membrane pemphigoid as a prototype

IMPORTANCE

Laminin-332 is an important component of the basement membrane. Recently, autoantibodies to Laminin-332 have been described in several autoimmune diseases. Many of these autoimmune diseases have a high incidence of malignancy. The importance of Laminin-332 autoantibodies and its relationship to malignancy is highlighted by using Laminin-332 Pemphigoid (LM-332Pg) as a prototype.

OBJECTIVE

To identify several autoimmune diseases that have autoantibodies to Laminin-332 present, and to determine the prevalence of malignancy in them. Using Laminin-332 Pemphigoid (LM-332Pg) as a prototype, to compare clinical profiles of LM-332Pg patients with and without cancer. By identifying the temporal detection of cancer, can the influence of autoantibodies to Laminin-332 on prognosis be determined.

EVIDENCE REVIEW

A literature search was conducted to identify autoimmune and inflammatory diseases in which autoantibodies to Laminin-332 were present. Subsequently, the rate of malignancy in these autoimmune diseases was determined. A search for publications on LM-332Pg patients to determine cancer rates and clinical outcomes to examine if a relationship can be proposed, was performed.

FINDINGS

Autoantibodies to Laminin-332 were detected in recent studies of systemic lupus erythematosus (SLE), psoriasis, bronchiolitis obliterans (BO), graft-vs-host disease (GVH), bullous pemphigoid (BP), lichen planus (LP), epidermolysis bullosa acquisita (EBA), and membranous glomerulonephropathy (MGN). A high incidence of cancer rate was reported in these autoimmune diseases including primary Sjögren's syndrome (pSS), systemic sclerosis (SS), dermatomyositis (DM), multiple sclerosis (MS), immune thrombocytopenia purpura (ITP), and rheumatoid arthritis (RA). Data analysis demonstrated that LM-332Pg patients had a higher risk of developing ovarian, uterine, lung, gastric cancers and leukemia. The incidence for breast cancer was lower, when compared with global cancer rates. Patients diagnosed with cancer after the presence of LM-332Pg had higher rates of mortality and lower rates of remission, compared to those diagnosed with cancer prior to the discovery/diagnosis of LM-332Pg. When studied, levels of Laminin-332 autoantibodies correlated with the presence or absence of malignancy.

CONCLUSIONS AND RELEVANCE

Preliminary analysis suggests that autoantibodies to Laminin-332 are present in multiple autoimmune diseases, which also have a high incidence of malignancy. Detailed analysis of available data highlights that patients who developed LM-332Pg after cancer was diagnosed, had a more favorable prognosis, compared to patients who developed cancer when LM-332Pg was previously present. Preliminary data would suggest that autoantibodies to Laminin-332 could serve as an important biomarker in certain patients, for correlation with possible incidence of malignancy.

Autoimmunity against laminin 332

Laminin 332 is a heterotrimeric structural protein of the basal membrane zone (BMZ) of the skin and adjacent mucosal tissues. The importance of laminin 332 for the structural integrity of the BMZ is demonstrated by mutations in any of the three genes encoding for its three chains causing variants of junctional epidermolysis bullosa. Autoimmunity against laminin 332 is observed in mucous membrane pemphigoid (MMP) and in the rare patients with orf-induced pemphigoid. MMP is an autoimmune blistering disease with predominant mucosal manifestations and autoantibodies against the BMZ of the skin and orifice-close mucous membranes. The main autoantigens of MMP are type XVII collagen (BP180) and laminin 332 targeted in about 80% and 10-20% of patients, respectively. An increasing number of studies has highlighted the association of anti-laminin 332 MMP and malignancies that can be revealed in about a quarter of these patients. This data has led to the recommendation of current guidelines to assay for anti-laminin 332 reactivity in all MMP patients. The present review focuses on anti-laminin 332 MMP describing clinical features, its pathophysiology, and detection of serum anti-laminin 332 IgG. In addition, the available data about the occurrence of malignancies in anti-laminin 332 MMP, the underlying tumor entities, and its biology are detailed.

Characterization of laminin-332 gene expression in molecular subtypes of human bladder cancer

Human bladder cancer (BCa) exhibits morphological and molecular heterogeneity which can complicate treatment. Morphologically, more than 90% of BCa is classified as urothelial cell carcinoma (UCC). Among other histological variants, UCC with squamous differentiation (SqD) shows a worse prognosis than pure UCC. In addition, basal-squamous BCa is enriched for SqD, and these tumors have a poor prognosis. Therefore, it is critical to elucidate the mechanisms to drive the basal-squamous phenotype of human BCa. Laminin-332 is a major glycoprotein of the epithelial basement membrane. It is well known that laminin-332 is a favorable target for extracellular matrix proteases such as matrix metalloproteinases (MMPs) in various diseases. Accumulating evidence indicates the significant role of laminin-332 in tumorigenesis. Here, we analyzed the expression of laminin-332 genes (LAMA3, LAMB3, LAMC2) in molecular subtypes of human BCa using publicly available data from The Cancer Genome Atlas (TCGA). Additionally, we also used q-RT-PCR to characterize laminin-332 gene expression between distinct molecular subtypes of human BCa cell lines. Our analysis of publicly available data show that laminin-332 genes are highly expressed in the basal-squamous molecular subtype of human BCa. In addition, we show laminin-332 genes are highly expressed in basal-squamous human BCa cell lines. Moreover, the expression of both LAMA3 and LAMC2 are negatively correlated with expression of the luminal transcription factor (TF) FOXA1 in the TCGA data. We also demonstrate that laminin-332 genes are downregulated by the overexpression of FOXA1 in a human basal-squamous BCa cell line (5637). Taken together, these results suggest that laminin-332 gene expression may be a biomarker of BCa patients with basal-squamous disease.

Anti-Laminin 332-Type Mucous Membrane Pemphigoid

Anti-laminin (LM) 332-type mucous membrane pemphigoid (MMP) is a rare autoimmune bullous disease and was originally discovered as anti-epiligrin cicatricial pemphigoid. Anti-LM332-type MMP has clinical manifestations similar to those of other types of MMP and can only be distinguished through the detection of circulating autoantibodies against LM332. Our group and others have established a number of immunological methods with varying sensitivity and specificity for detection of anti-LM332 autoantibodies; however, none of the established methods has been widely used for clinical diagnosis. There is currently no unified standard treatment, and it is very difficult to completely cure anti-LM332-type MMP. In addition, an increasing body of evidence suggests that there may be a strong correlation between anti-LM332-type MMP and tumors. In this article, we review the current progression of diagnosis and treatment of anti-LM332-type MMP, as well as the possible correlation between anti-LM332-type MMP and tumors.

Invasion-Associated Reorganization of Laminin 332 in Oral Squamous Cell Carcinomas: The Role of the Laminin γ2 Chain in Tumor Biology, Diagnosis, and Therapy

Simple Summary

The destructive growth of carcinomas is associated with crossing the border between the epithelial and the connective tissue parts of an organ. One component of this borderline, the basement membrane, is the heterotrimeric laminin 332, which mediates the adhesion of basal epithelial cells. This protein, in particular its gamma 2 chain, is fundamentally reorganized during tumor cell invasion. Specific deposition patterns of laminin 332 are also present in oral squamous cell carcinomas and have been shown to be of high diagnostic and predictive value. Furthermore, laminin 332 restructuring is associated with important tumor biological processes, e.g., stromal activation, the development of a motile phenotype, and tumor spreading. In this review, current knowledge in the field is summarized and the recommendation to consider laminin 332 as a promising grading and monitoring parameter and as a potential therapeutic target is discussed.

Abstract

Invasion of the connective tissue by carcinoma cells is accompanied by disintegration and reorganization of the hemidesmosomes, which connect the basement membrane to the basal epithelial cells. In terms of mediating the basement membrane, i.e., basal cell interactions, the heterotrimeric laminin 332 is the most important bridging molecule. Due to this distinct function, laminin 332, especially its gamma 2 chain, came into the focus of cancer research. Specific de novo synthesis and deposition patterns of laminin 332 are evident upon development and progression of oral squamous cell carcinomas (OSCCs). Loss from the basement membrane, cytoplasmic accumulation, and extracellular deposition are associated with crucial processes such as stromal activation and immune response, epithelial to mesenchymal transition, and tumor cell budding. In networks with components of the tumor microenvironment, altered expression of laminin 332 chains, proteolytic processing, and interaction with integrin receptors seem to promote cancer cell migration. Indeed, reorganization patterns are shown to have a high diagnostic and prognostic value. Here, we summarize the current knowledge on laminin 332 reorganization in OSCCs with special focus on its gamma 2 chain and provide, based on the current literature, evidence on its promising role as a grading and monitoring parameter and as a potential therapeutic target.

ARRDC3 inhibits liver fibrosis and epithelial-to-mesenchymal transition via the ITGB4/PI3K/Akt signaling pathway

Objective The effect of ARRDC3 has not been reported in liver fibrosis. Our study aimed to explore the molecular mechanisms by which ARRDC3 attenuates liver fibrosis.Methods The vectors pcDNA-ARRDC3 (which promotes ARRDC3 expression) and si-ITGB4 (which blocks IGTB4 expression) and their negative controls were constructed. The rat liver fibrosis model was established by intraperitoneal injection of CCl4 with or without intraperitoneal injection of pcDNA-ARRDC3. ELISA was used to detect the concentrations of γ-GGT, ALT, AST, and ALP in serum. HE, Masson's trichome, and Sirius red staining were used to observe the pathological changes in liver tissue. LX-2 cells were treated with TGF-β, and pcDNA-ARRDC3 or si-ITGB4RNA was transfected to promote ARRDC3 expression or knock down ITGB4 expression. Western blotting was used to detect the expression levels of proteins.Results ARRDC3 effectively reduced liver injury, improved liver function, and decreased collagen production and deposition in the CCl4-induced rat fibrosis model. The studies showed that overexpressed ARRDC3 remarkably reduced the expression of E-cadherin and collagen-related protein and increased the expression of mesenchymal markers and EMT-related transcription factors, consequently inhibiting the activity of the ITGB4/PI3K/Akt signaling pathway.Conclusion Our study shows that ARRDC3 could ameliorate CCl4-induced liver fibrosis and EMT progression via the ITGB4/PI3K/Akt signaling pathway, which provides a meaningful reference for the clinical targeted treatment of liver fibrosis.

Polymeric immunoglobulin receptor suppresses colorectal cancer through the AKT-FOXO3/4 axis by downregulating LAMB3 expression

Colorectal cancer (CRC) remains one of the most common malignancies worldwide and its mechanism is unclear. Polymeric immunoglobulin receptor (PIGR) which plays an important role in mucosal immunity is widely expressed in the mucosal epithelium and is dysregulated in different tumors. However, the role and underlying mechanisms of PIGR in CRC remain unclear. Here, we demonstrated that PIGR was hypermethylated and downregulated in our cohort (N = 272), and these features were associated with reduced overall survival in patients (HRmethylation 1.61, 95% CI [1.11-2.33]). These findings were validated by external TCGA and GEO data. Moreover, PIGR overexpression inhibits CRC cell malignant phenotypes in vitro and impedes CRC cells growth in male BALB/c nude mice. Mechanistically, PIGR physically associates with RE1 silencing transcription factor (REST) and blocks the transcription of laminin subunit beta 3 (LAMB3). Subsequently, the AKT-FOXO3/4 axis was suppressed by downregulated LAMB3. In the drug sensitive assay, PIGR-overexpressing cells were more sensitive to cisplatin and gemcitabine. Together, PIGR may serve as a powerful prognostic biomarker and putative tumor suppressor by suppressing the AKT-FOXO3/4 axis by downregulating LAMB3 in CRC. Our study may offer a novel therapeutic strategy for treating CRC patients who highly express PIGR with cisplatin and gemcitabine.

Oncogenic KRAS-Induced Protein Signature in the Tumor Secretome Identifies Laminin-C2 and Pentraxin-3 as Useful Biomarkers for the Early Diagnosis of Pancreatic Cancer

KRAS mutations characterize pancreatic cell transformation from the earliest stages of carcinogenesis, and are present in >95% of pancreatic ductal adenocarcinoma (PDAC) cases. In search of novel biomarkers for the early diagnosis of PDAC, we identified the proteins secreted by the normal human pancreatic cell line (HPDE) recently transformed by inducing the overexpression of the KRASG12V oncogene. We report a proteomic signature of KRAS-induced secreted proteins, which was confirmed in surgical tumor samples from resected PDAC patients. The putative diagnostic performance of three candidates, Laminin-C2 (LAMC2), Tenascin-C (TNC) and Pentraxin-3 (PTX3), was investigated by ELISA quantification in two cohorts of PDAC patients (n = 200) eligible for surgery. Circulating levels of LAMC2, TNC and PTX3 were significantly higher in PDAC patients compared to the healthy individuals (p < 0.0001). The Receiver Operating Characteristics (ROC) curve showed good sensitivity (1) and specificity (0.63 and 0.85) for LAMC2 and PTX3, respectively, but not for TNC, and patients with high levels of LAMC2 had significantly shorter overall survival (p = 0.0007). High levels of LAMC2 and PTX3 were detected at early stages (I−IIB) and in CA19-9-low PDAC patients. In conclusion, pancreatic tumors release LAMC2 and PTX3, which can be quantified in the systemic circulation, and may be useful in selecting patients for further diagnostic imaging.

Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a clinically and immunopathologically heterogenous disease with an incidence of about 2/million inhabitants/year in central Europe. Pemphigoid diseases are characterized by autoantibodies against structural proteins of the epidermis and/or surface-close epithelia. MMP has been defined as pemphigoid disease with predominant mucosal lesions. Most frequently, the oral cavity and the conjunctivae are affected. Lesions outside the mouth tend to heal with scarring leading to visual impairment and finally blindness, as well as, more rarely, impairment of breathing and food intake. Autoantibodies target BP180 (collagen type XVII), laminin 332, BP230 (nearly always in conjunction with other antigens), and type VII collagen in about 75%, 10-20%, 10-30%, and <5% of MMP patients, respectively. While the main autoantibody isotype is IgG, additional, and less frequently, exclusive IgA autoantibodies can be detected in the majority of patients. Assaying for anti-laminin 332 reactivity is pivotal, since in about a quarter of patients with anti-laminin 332 MMP, a malignancy, mainly solid cancers, is associated. The pathophysiology of MMP is yet incompletely understood. A recent mouse model of anti-laminin 332 MMP replicating characteristic clinical and immunopathological findings of the human disease may be helpful to close this knowledge gap. Diagnosis is established by the clinical picture with predominant mucosal lesions and visualization of tissue-bound anti-basement membrane zone antibodies by direct immunofluorescence microscopy. In recent S3 guidelines initiated by the European Academy of Dermatology and Venereology, the clinical spectrum and diagnostic strategies are detailed. In addition, treatment regimens for different clinical situations including patients with exclusive oral or ocular involvement are outlined. Future studies are needed to better understand the clinal complexity and associations as well as to establish widely available diagnostic assays and evidence-based therapeutic strategies.

Novel LAMC2 fusion protein has tumor-promoting properties in ovarian carcinoma

Laminins are heterotrimeric ECM proteins composed of α, β, and γ chains. The γ2 chain (Lm-γ2) is a frequently expressed monomer and its expression is closely associated with cancer progression. Laminin-γ2 contains an epidermal growth factor (EGF)-like domain in its domain III (DIII or LEb). Matrix metalloproteinases can cleave off the DIII region of Lm-γ2 that retains the ligand activity for EGF receptor (EGFR). Herein, we show that a novel short form of Lm-γ2 (Lm-γ2F) containing DIII is generated without requiring MMPs and chromosomal translocation between LAMC2 on chromosome 1 and NR6A1 gene locus on chromosome 9 in human ovarian cancer SKOV3 cells. Laminin-γ2F is expressed as a truncated form lacking domains I and II, which are essential for its association with Lm-α3 and -β3 chains of Lm-332. Secreted Lm-γ2F can act as an EGFR ligand activating the EGFR/AKT pathways more effectively than does the Lm-γ2 chain, which in turn promotes proliferation, survival, and motility of ovarian cancer cells. LAMC2-NR6A1 translocation was detected using in situ hybridization, and fusion transcripts were expressed in ovarian cancer cell tissues. Overexpression and suppression of fusion transcripts significantly increased and decreased the tumorigenic growth of cells in mouse models, respectively. To the best of our knowledge, this is the first report regarding a fusion gene of ECM showing that translocation of LAMC2 plays a crucial role in the malignant growth and progression of ovarian cancer cells and that the consequent product is a promising therapeutic target against ovarian cancers.

Comparative study of laminin332-γ2 chain expression in oral lichen planus and squamous cell carcinoma by immunohistochemistry

BACKGROUND

Classification of oral lichen planus (OLP) as a condition with malignant potential is still controversial. One of the major properties of malignancy is invasion. Ln332-γ2 chain plays a critical role in invasive activity of cancer cells. This study aims to compare Ln332-γ2 chain expression in OLP, oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC).

METHODS

Ln332-γ2 expression was evaluated in 16 epithelial hyperplasia with no dysplasia (group A), 16 OLP (group B), 18 OED (group C) and 18 OSCC (group D) by immunohistochemistry.

RESULTS

Except in A group, Ln332-γ2 expression was detected in other groups. There was a significant difference in Ln332-γ2 expression among B, C and D groups as well as between B and D, C and D groups (P< 0.001). However, there was no significant difference between B and C groups (P= 0.999).

CONCLUSIONS

According to the findings of this study, the likelihood of similarity of OLP with premalignant dysplastic lesion can be suggested. This is not corroborating OLP definitive transformation to an OSCC. But it might be advisable that OLPs with >10% Ln332- γ2 expression may have a higher risk of cellular invasion occurrence and malignant transformation.

Potential Therapeutic Significance of Laminin in Head and Neck Squamous Carcinomas

Simple Summary

Head and neck cancers (HNC) account for approximately 500,000 new cases of tumors annually worldwide and are represented by upper aerodigestive tract malignant neoplasms, which particularly arise in oral cavity, larynx, and pharynx tissues. Thus, due to the biological diversity between the upper aerodigestive organs, and to the heterogeneity of risk factors associated with their malignant transformation, HNC behavior, and prognosis seem to strongly vary according to the tumor site. However, despite to the heterogeneity which characterizes head and neck tumors, squamous cell carcinomas (SCC) represent the predominant histopathologic HNC subtype. In this sense, it has been reported that SCC tumor biology is strongly associated with deregulations within the extracellular matrix compartment. Accordingly, it has been shown that laminin plays a remarkable role in the regulation of crucial events associated with head and neck squamous cell carcinomas (HNSCC) progression, which opens the possibility that laminin may represent a convergence point in HNSCC natural history.

Abstract

Head and neck squamous cell carcinomas (HNSCC) are among the most common and lethal tumors worldwide, occurring mostly in oral cavity, pharynx, and larynx tissues. The squamous epithelia homeostasis is supported by the extracellular matrix (ECM), and alterations in this compartment are crucial for cancer development and progression. Laminin is a fundamental component of ECM, where it represents one of the main components of basement membrane (BM), and data supporting its contribution to HNSCC genesis and progression has been vastly explored in oral cavity squamous cell carcinoma. Laminin subtypes 111 (LN-111) and 332 (LN-332) are the main isoforms associated with malignant transformation, contributing to proliferation, adhesion, migration, invasion, and metastasis, due to its involvement in the regulation of several pathways associated with HNSCC carcinogenesis, including the activation of the EGFR/MAPK signaling pathway. Therefore, it draws attention to the possibility that laminin may represent a convergence point in HNSCC natural history, and an attractive potential therapeutic target for these tumors.

Laminin‑332 mediates proliferation, apoptosis, invasion, migration and epithelial‑to‑mesenchymal transition in pancreatic ductal adenocarcinoma

The poor prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is primarily due to the invasive and metastatic behaviors of this disease. Laminin‑332 (LM‑332) is a key component of the basement membrane barrier, and is associated with tumor metastasis. The present study provides evidence towards the potential function of LM‑332 in carcinoma, indicating the distinct roles of the three LM‑332 subunits (α3, β3 and γ2) in cell proliferation, migration, invasion, apoptosis and the epithelial‑to‑mesenchymal transition (EMT) in cancer. The roles of the α3, β3 and γ2 subunits in the malignant biological behavior of PDAC were investigated in the present study. It was revealed that the α3, β3 and γ2 subunits were upregulated in PDAC. Inhibition of all LM‑332 subunits abrogated the tumorigenic outcomes, which included cell proliferation, apoptosis, invasion, migration and EMT in vitro. However, the three LM‑332 subunits had different degrees of effects on biological behavior. It was observed that LAMA3 (α3) had a stronger effect on cell proliferation, migration and invasion. In addition, LAMB3 (β3) knockdown significantly increased E‑cadherin levels and decreased vimentin levels, indicating that LAMB3 was associated with EMT. Likewise, LAMC2 (γ2) mediated proliferation, apoptosis, invasion and migration. However, small interfering (si)‑LAMC2 promoted the progression of EMT, which was the opposite effect to that of si‑LAMB3. The LM‑332 subunits (α3, β3 and γ2) may be novel therapeutic targets of PDAC in the future.

Engineering the Extracellular Matrix to Model the Evolving Tumor Microenvironment

Clinical evidence supports a role for the extracellular matrix (ECM) in cancer risk and prognosis across multiple tumor types, and numerous studies have demonstrated that individual ECM components impact key hallmarks of tumor progression (e.g., proliferation, migration, angiogenesis). However, the ECM is a complex network of fibrillar proteins, glycoproteins, and proteoglycans that undergoes dramatic changes in composition and organization during tumor development. In this review, we will highlight how engineering approaches can be used to examine the impact of changes in tissue architecture, ECM composition (i.e., identity and levels of individual ECM components), and cellular- and tissue-level mechanics on tumor progression. In addition, we will discuss recently developed methods to model the ECM that have not yet been applied to the study of cancer.

H-Ras activation and fibroblast-induced TGF-β signaling promote laminin-332 accumulation and invasion in cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer, with increasing incidence worldwide. The molecular basis of cSCC progression to invasive and metastatic disease is still incompletely understood. Here, we show that fibroblasts and transforming growth factor-β (TGF-β) signaling promote laminin-332 synthesis in cancer cells in an activated H-Ras-dependent manner, which in turn promotes cancer cell invasion. Immunohistochemical analysis of sporadic UV-induced invasive human cSCCs (n = 208) revealed prominent cSCC cell specific immunostaining for laminin-332 γ2 chain, located in the majority of cases (90%, n = 173) in the invasive edge of the tumors. To mimic the progression of cSCC we established 3D spheroid cocultures using primary skin fibroblasts and HaCaT/ras-HaCaT human keratinocytes. Our results indicate that in 3D spheroids, unlike in monolayer cultures, TGF-β upregulates laminin-332 production, but only in cells that harbour oncogenic H-Ras. Accumulation of laminin-332 was prevented by both H-Ras knock down and inhibition of TGF-β signaling by SB431542 or RAdKD-ALK5 kinase-defective adenovirus. Furthermore, fibroblasts accelerated the invasion of ras-HaCaT cells through collagen I gels in a Ras/TGF-β signaling dependent manner. In conclusion, we demonstrate the presence of laminin-332 in the invasive front of cSCC tumors and report a new Ras/TGF-β-dependent mechanism that promotes laminin-332 accumulation and cancer cell invasion.

Laminin 332 in cancer: When the extracellular matrix turns signals from cell anchorage to cell movement

Laminin 332 is crucial in the biology of epithelia. This large extracellular matrix protein consists of the heterotrimeric assembly of three subunits - α3, β3, and γ2 - and its multifunctionality relies on a number of extracellular proteolytic processing events. Laminin 332 is central to normal epithelium homeostasis by sustaining cell adhesion, polarity, proliferation, and differentiation. It also supports a major function in epithelial tissue formation, repair, and regeneration by buttressing cell migration and survival and basement membrane assembly. Interest in this protein increased after the discovery that its expression is perturbed in tumor cells, cancer-associated fibroblasts, and the tumor microenvironment. This review summarizes current knowledge regarding the established involvement of the laminin 332 γ2 chain in tumor invasiveness and discusses the role of its α3 and β3 subunits.

Deregulated expression of Elastin Microfibril Interfacer 2 (EMILIN2) in gastric cancer affects tumor growth and angiogenesis

Gastric cancer is a frequent human tumor and often a lethal disease. Targeted therapy for gastric carcinomas is far behind vis-à-vis other solid tumors, primarily because of the paucity of cancer-driving mutations that could be efficiently and specifically targeted by current therapy. Thus, there is a need to discover actionable pathways/proteins and new diagnostic and prognostic biomarkers. In this study, we explored the role of the extracellular matrix glycoprotein EMILIN2, Elastin Microfibril Interfacer 2, in a cohort of gastric cancer patients. We discovered that EMILIN2 expression was consistently suppressed in gastric cancer and high expression levels of this glycoprotein were linked to abnormal vascular density. Furthermore, we found that EMILIN2 had a dual effect on gastric carcinoma cells: on one hand, it decreased tumor cell proliferation by triggering apoptosis, and on the other hand, it evoked the production of a number of cytokines involved in angiogenesis and inflammation, such as IL-8. Collectively, our findings posit EMILIN2 as an important onco-regulator exerting pleiotropic effects on the gastric cancer microenvironment.

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EMILIN2 is localized in the gastric lamina propria and its expression is down-regulated in gastric cancer.

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High levels of EMILIN2 associate with elevated vascular density.

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EMILIN2 impairs the proliferation of gastric cancer cells by evoking apoptosis.

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Surprisingly, EMILIN2 triggers the expression of pro-angiogenic and pro-inflammatory cytokines.

Epidermolysis Bullosa-Associated Squamous Cell Carcinoma: From Pathogenesis to Therapeutic Perspectives

Epidermolysis bullosa (EB) is a heterogeneous group of inherited skin disorders determined by mutations in genes encoding for structural components of the cutaneous basement membrane zone. Disease hallmarks are skin fragility and unremitting blistering. The most disabling EB (sub)types show defective wound healing, fibrosis and inflammation at lesional skin. These features expose patients to serious disease complications, including the development of cutaneous squamous cell carcinomas (SCCs). Almost all subjects affected with the severe recessive dystrophic EB (RDEB) subtype suffer from early and extremely aggressive SCCs (RDEB-SCC), which represent the first cause of death in these patients. The genetic determinants of RDEB-SCC do not exhaustively explain its unique behavior as compared to low-risk, ultraviolet-induced SCCs in the general population. On the other hand, a growing body of evidence points to the key role of tumor microenvironment in initiation, progression and spreading of RDEB-SCC, as well as of other, less-investigated, EB-related SCCs (EB-SCCs). Here, we discuss the recent advances in understanding the complex series of molecular events (i.e., fibrotic, inflammatory, and immune processes) contributing to SCC development in EB patients, cross-compare tumor features in the different EB subtypes and report the most promising therapeutic approaches to counteract or delay EB-SCCs.

Mechanism of anchorage-independency and tumor formation of cancer cells: possible involvement of cell membrane-bound laminin-332

Cancer cells are characterized by anchorage-independency and tumor formation. Involvement of laminin-332 in the pathogenesis of cancer has also been reported. I present a theory that can explain these characteristics together. Proliferating keratinocytes in wound healing produce and deposit laminin-332, which is shown in the provisional basement membrane of a wound. In association with wound closure, expression of LG4/5 domain on the α3 chain of laminin-332 disappears, implicating cleavage of LG4/5 domain. LG4/5 domain expression indicates that laminin-332 prior to the cleavage is bound to the cell membrane, because LG4/5 domain is a cell binding site. In this binding, heparan sulfate proteoglycan on the cell surface seems to be the acceptor for LG4/5 domain. I named this laminin "cell membrane-bound laminin-332" (ML332). ML332 would then bind to integrin α3β1 via LG1-3 domain, the integrin binding site, and activate FAK and the following Ras/MAPK pathway. Therefore, ML332 eliminates the need for proliferating keratinocytes to bind to processed laminin-332 secreted and deposited into the basement membrane for their proliferation (anchorage-independency). This may hold true of every proliferating epithelial cell, either benign or malignant. Whereas wound closure deprives keratinocytes of anchorage-independency, such events do not occur in cancer cells, and cancer cells maintain anchorage-independency. In the basement membrane formation by epithelial cells, short arms of laminin-332 anchored to the cell membrane bind each other and generate a meshwork polymer. This is the three-arm interaction model. In a similar manner, short-arm interactions between adjacent cancer cells may occur and induce tumor formation.

Expression of integrins to control migration direction of electrotaxis

Proper control of cell migration is critically important in many biologic processes, such as wound healing, immune surveillance, and development. Much progress has been made in the initiation of cell migration; however, little is known about termination and sometimes directional reversal. During active cell migration, as in wound healing, development, and immune surveillance, the integrin expression profile undergoes drastic changes. Here, we uncovered the extensive regulatory and even opposing roles of integrins in directional cell migration in electric fields (EFs), a potentially important endogenous guidance mechanism. We established cell lines that stably express specific integrins and determined their responses to applied EFs with a high throughput screen. Expression of specific integrins drove cells to migrate to the cathode or to the anode or to lose migration direction. Cells expressing αMβ2, β1, α2, αIIbβ3, and α5 migrated to the cathode, whereas cells expressing β3, α6, and α9 migrated to the anode. Cells expressing α4, αV, and α6β4 lost directional electrotaxis. Manipulation of α9 molecules, one of the molecular directional switches, suggested that the intracellular domain is critical for the directional reversal. These data revealed an unreported role for integrins in controlling stop, go, and reversal activity of directional migration of mammalian cells in EFs, which might ensure that cells reach their final destination with well-controlled speed and direction.-Zhu, K., Takada, Y., Nakajima, K., Sun, Y., Jiang, J., Zhang, Y., Zeng, Q., Takada, Y., Zhao, M. Expression of integrins to control migration direction of electrotaxis.

A preliminary attempt to explore the potential functions of a tetraspanin gene (MmTSPAN) in the innate immunity of hard clam Meretrix meretrix: Sequence features and expression profiles

Tetraspanins belong to the transmembrane 4 superfamily (TM4SF), and play crucial roles in immune responses. In the present study, a novel tetraspanin gene (designated MmTSPAN) was cloned and characterized from the hard clam Meretrix meretrix. The complete cDNA sequence of MmTSPAN contained an open reading frame (ORF) of 816 bp, which encoded a protein of 271 amino acids. MmTSPAN exhibited highly similarity with previously identified tetraspanins from other species. It contained four transmembrane domains (12-35 aa, 69-92 aa, 99-123 aa and 238-261 aa), characteristic CCG motif and four conservative cysteine residues. The mRNA transcripts of MmTSPAN were ubiquitously detectable in all the tested tissues, with the highest expression level in hepatopancreas. Temporal transcriptional levels in the hepatopancreas revealed significant up-regulation of MmTSPAN by Vibrio splendidus stimulation, with a 3.14-fold increase at 6 h compared to the control, and reaching 32.98-fold at 24 h. These results provide useful information for further study of the function of tetraspanin in the innate immune system of M. meretrix, and may offer a new therapeutic target for diseases of M. meretrix.

The extracellular matrix in tumor progression and metastasis

The extracellular matrix (ECM) constitutes the scaffold of tissues and organs. It is a complex network of extracellular proteins, proteoglycans and glycoproteins, which form supramolecular aggregates, such as fibrils and sheet-like networks. In addition to its biochemical composition, including the covalent intermolecular cross-linkages, the ECM is also characterized by its biophysical parameters, such as topography, molecular density, stiffness/rigidity and tension. Taking these biochemical and biophysical parameters into consideration, the ECM is very versatile and undergoes constant remodeling. This review focusses on this remodeling of the ECM under the influence of a primary solid tumor mass. Within this tumor stroma, not only the cancer cells but also the resident fibroblasts, which differentiate into cancer-associated fibroblasts (CAFs), modify the ECM. Growth factors and chemokines, which are tethered to and released from the ECM, as well as metabolic changes of the cells within the tumor bulk, add to the tumor-supporting tumor microenvironment. Metastasizing cancer cells from a primary tumor mass infiltrate into the ECM, which variably may facilitate cancer cell migration or act as barrier, which has to be proteolytically breached by the infiltrating tumor cell. The biochemical and biophysical properties therefore determine the rates and routes of metastatic dissemination. Moreover, primed by soluble factors of the primary tumor, the ECM of distant organs may be remodeled in a way to facilitate the engraftment of metastasizing cancer cells. Such premetastatic niches are responsible for the organotropic preference of certain cancer entities to colonize at certain sites in distant organs and to establish a metastasis. Translational application of our knowledge about the cancer-primed ECM is sparse with respect to therapeutic approaches, whereas tumor-induced ECM alterations such as increased tissue stiffness and desmoplasia, as well as breaching the basement membrane are hallmark of malignancy and diagnostically and histologically harnessed.

LAMB3 is associated with disease progression and cisplatin cytotoxic sensitivity in head and neck squamous cell carcinoma

OBJECTIVES

Laminin subunit beta-3 (LAMB3) is a major component of the basement membrane zone. In our study, we investigated the role of LAMB3 in head and neck squamous cell carcinoma (HNSCC) progression and its clinical implication as a prognostic biomarker.

MATERIALS AND METHODS

A retrospective analysis of 100 patients with HNSCC who had undergone curative surgery from 1999 to 2011 was performed. We evaluated LAMB3 expression by immunohistochemistry and its associations with clinicopathological characteristics and survival. For functional in vitro analyses, cell proliferation, migration, and invasion and western blot assays were performed following LAMB3 suppression. In addition, the role of LAMB3 in cisplatin-induced cytotoxicity was clarified by measuring cell proliferation.

RESULTS

LAMB3 expression was up-regulated in HNSCC cell lines and patient tissues. High LAMB3 expression was significantly associated with positive lymph node metastasis (odds ratio: 6.316; P < 0.001) and poor prognosis in patients with HNSCC. LAMB3 suppression reduced cell migration/invasion via down-regulation of epithelial-to-mesenchymal transition-associated proteins (Vimentin and Slug). Moreover, LAMB3 suppression increased cisplatin cytotoxicity in HNSCC cells.

CONCLUSION

Our findings indicate that LAMB3 may be used as a prognostic biomarker in HNSCC and support that LAMB3 silencing could induce the sensitivity of anti-cancer drugs such as cisplatin.

Unique Biological Activity and Potential Role of Monomeric Laminin-γ2 as a Novel Biomarker for Hepatocellular Carcinoma: A Review

Laminin (Ln)-332 consists of α3, β3, and γ2 chains, which mediate epithelial cell adhesion to the basement membrane. Ln-γ2, a component of Ln-332, is frequently expressed as a monomer in the invasion front of several types of malignant tissues without simultaneous expression of Ln-α3 and/or Ln-β3 chains. Moreover, monomeric Ln-γ2 induces tumor cell proliferation and migration in vitro. These unique biological activities indicate that monomeric Ln-γ2 could be a candidate biomarker for early cancer surveillance. However, the present immune method for monomeric Ln-γ2 detection can only predict its expression, since no antibody that specifically reacts with monomeric γ2, but not with heterotrimeric γ2 chain, is commercially available. We have, therefore, developed monoclonal antibodies to specifically detect monomeric Ln-γ2, and devised a highly sensitive method to measure serum monomeric Ln-γ2 levels using a fully automated chemiluminescent immunoassay (CLIA). We evaluated its diagnostic value in sera from patients with several digestive cancers, including hepatocellular carcinoma (HCC), and found serum monomeric Ln-γ2 to be a clinically available biomarker for HCC surveillance. The combination of monomeric Ln-γ2 and prothrombin induced by Vitamin K Absence II (PIVKA-II) may be more sensitive for clinical diagnosis of HCC than any currently used combination.

The Interaction between Laminin-332 and α3β1 Integrin Determines Differentiation and Maintenance of CAFs, and Supports Invasion of Pancreatic Duct Adenocarcinoma Cells

Ranking among the most lethal tumour entities, pancreatic duct adenocarcinoma cells invade neighbouring tissue resulting in high incidence of metastasis. They are supported by tumour stroma fibroblasts which have undergone differentiation into cancer-associated fibroblasts (CAFs). Stiffness of cell substratum, cytokines, such as transforming growth factor-β (TGF-β), and stromal matrix proteins, such as laminin-332, are factors which promote CAF differentiation. In a spheroid culture system, differentiation of CAFs was analysed for laminin-332 production, laminin-binding integrin repertoire, adhesion and migration behaviour, and, in heterospheroids, for their interplay with the pancreatic duct adenocarcinoma AsPC-I cells. Our data reveal that CAFs produce laminin-332 thus contributing to its ectopic deposition within the tumour stroma. Moreover, CAF differentiation correlates with an increased expression of α3β1 integrin, the principal laminin-332-receptor. Beyond its role as novel CAF marker protein, integrin α3β1 crucially determines differentiation and maintenance of the CAF phenotype, as knock-out of the integrin α3 subunit reversed the CAF differentiated state. AsPC-I cells co-cultured in heterospheroids with integrin α3-deficient CAFs invaded less than from heterospheroids with wild-type CAFs. This study highlights the role of integrin α3β1 integrin-laminin-332 interaction of CAFs which promotes and sustains differentiation of CAFs and promotes carcinoma invasion.

Laminin 332 expression and prognosis in breast cancer

The purpose of this study was to determine the distribution of and potential significance of laminin 332 (LM332) in breast cancer. Specimens from a population-based cohort (N = 297) from 1994 to 1995 were stained for estrogen receptor (ER), progesterone receptor (PgR), HER2 and the LM332 β3 chain. Seventy-five tumors were LM332-positive and 222 were negative. LM332 β3 stained 16.0% of ER and/or PgR-positive tumors and 73.2% of triple-negative breast cancers (TNBC). Immunoblotting revealed LM332 in TNBC and HER2-positive samples, but not in an ER-positive breast carcinoma or a phyllodes tumor. After 20 years, 172 patients were alive, 43 had died of breast cancer and 82 of other causes. Patients with LM332-positive tumors had significantly worse 5 (P < .0001) and 10-year (P < .05) overall and breast cancer specific survival. Among patients with LM332 β3-expressing and ER/PgR-negative carcinomas, 10-year survival was significantly reduced (P < .0450). In a multivariate analysis LM332-positive patients had significant hazard ratios of 3.9 with 95% confidence intervals (CI) of 2.0-7.7 and 2.2 with 95% CI of 1.3-3.8 for 5 and 10-year overall survival, respectively. Because tumor cell motility is required for metastasis, the effect of LM332 on MDA-MB-231 migration was determined using siRNA. Knockdown of LM332-specific β3 and γ2 chains reduced motility without affecting viability. Our observation that LM332 in breast carcinoma is associated with decreased survival provides evidence that LM332 may have a role in the aggressive phenotype of some breast cancers.

Overexpression of α3, β3 and γ2 chains of laminin-332 is associated with poor prognosis in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a worldwide health problem. Early diagnosis and assessment may enhance the quality of life and survival of patients. The present study investigated the potential correlations between the gene and protein expression of laminin-332 (LM-332 or laminin-5) and clinicopathological factors as well as evaluating its influence on the survival of patients with PDA. The expression of LM-332 subunit mRNAs in pancreatic carcinoma specimens from 37 patients was investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. Using immunohistochemical methods, the protein expressions of the three chains of LM-322 (LNα3, LNβ3 and LNγ2) were determined in 96 pancreatic carcinoma specimens, for association analysis with clinicopathological characteristics from patient data. The results of the prognosis analysis of three mRNAs expression datasets were validated in The Cancer Genome Atlas datasets. RT-qPCR results indicated that the overall relative values of LNα3 and LNγ2 mRNAs were increased in pancreatic carcinoma compared with the control. In immunostaining analyses LNα3 and LNγ2 expression was observed in all tumor tissues from the 96 patient samples. The expression levels of LNα3, LNβ3 and LNγ2 were associated with each other. LNα3 and LNγ2 positivity was significantly associated with differentiation, depth of invasion and advanced stage (P<0.05). The samples were classified into three groups: Basement membrane (B) type, cytoplasmic (C) type and mixed (M) type, according to their LNγ2 immunohistochemical expression patterns. The B type correlated significantly with differentiation (P=0.010) and the M type was significantly associated with hepatic metastasis (P=0.031). Patients with B-type LNγ2 demonstrated significantly better outcomes than patients with the C or M type (P=0.012 and P=0.003, respectively). Overexpression of the α3, β3 and γ2 chains of LM-332 may serve an important role in the progression and prognosis of PDA.

Human Epididymis Protein 4 Promotes Events Associated with Metastatic Ovarian Cancer via Regulation of the Extracelluar Matrix

Human epididymis protein 4 (HE4) has received much attention recently due to its diagnostic and prognostic abilities for epithelial ovarian cancer. Since its inclusion in the Risk of Ovarian Malignancy Algorithm (ROMA), studies have focused on its functional effects in ovarian cancer. Here, we aimed to investigate the role of HE4 in invasion, haptotaxis, and adhesion of ovarian cancer cells. Furthermore, we sought to gain an understanding of relevant transcriptional profiles and protein kinase signaling pathways mediated by this multifunctional protein. Exposure of OVCAR8 ovarian cancer cells to recombinant HE4 (rHE4) promoted invasion, haptotaxis toward a fibronectin substrate, and adhesion onto fibronectin. Overexpression of HE4 or treatment with rHE4 led to upregulation of several transcripts coding for extracellular matrix proteins, including SERPINB2, GREM1, LAMC2, and LAMB3. Gene ontology indicated an enrichment of terms related to extracellular matrix, cell migration, adhesion, growth, and kinase phosphorylation. LAMC2 and LAMB3 protein levels were constitutively elevated in cells overexpressing HE4 and were upregulated in a time-dependent manner in cells exposed to rHE4 in the media. Deposition of laminin-332, the heterotrimer comprising LAMC2 and LAMB3 proteins, was increased in OVCAR8 cells treated with rHE4 or conditioned media from HE4-overexpressing cells. Enzymatic activity of matriptase, a serine protease that cleaves laminin-332 and contributes to its pro-migratory functional activity, was enhanced by rHE4 treatment in vitro. Proteomic analysis revealed activation of focal adhesion kinase signaling in OVCAR8 cells treated with conditioned media from HE4-overexpressing cells. Focal adhesions were increased in cells treated with rHE4 in the presence of fibronectin. These results indicate a direct role for HE4 in mediating malignant properties of ovarian cancer cells and validate the need for HE4-targeted therapies that will suppress activation of oncogenic transcriptional activation and signaling cascades.

Significant Role of Collagen XVII And Integrin β4 in Migration and Invasion of The Less Aggressive Squamous Cell Carcinoma Cells

Collagen XVII and integrin α6β4 have well-established roles as epithelial adhesion molecules. Their binding partner laminin 332 as well as integrin α6β4 are largely recognized to promote invasion and metastasis in various cancers, and collagen XVII is essential for the survival of colon and lung cancer stem cells. We have studied the expression of laminin γ2, collagen XVII and integrin β4 in tissue microarray samples of squamous cell carcinoma (SCC) and its precursors, actinic keratosis and Bowen's disease. The expression of laminin γ2 was highest in SCC samples, whereas the expression of collagen XVII and integrin β4 varied greatly in SCC and its precursors. Collagen XVII and integrin β4 were also expressed in SCC cell lines. Virus-mediated RNAi knockdown of collagen XVII and integrin β4 reduced the migration of less aggressive SCC-25 cells in horizontal scratch wound healing assay. Additionally, in a 3D organotypic myoma invasion assay the loss of collagen XVII or integrin β4 suppressed equally the migration and invasion of SCC-25 cells whereas there was no effect on the most aggressive HSC-3 cells. Variable expression patterns and results in migration and invasion assays suggest that collagen XVII and integrin β4 contribute to SCC tumorigenesis.

Integrin alpha6 maintains the structural integrity of the kidney collecting system

Laminins are a major constituent of the basement membranes of the kidney collecting system. Integrins, transmembrane receptors formed by non-covalently bound α and β subunits, serve as laminin receptors, but their role in development and homeostasis of the kidney collecting system is poorly defined. Integrin α3β1, one of the major laminin receptors, plays a minor role in kidney collecting system development, while the role of α6 containing integrins (α6β1 and α6β4), the other major laminin receptors, is unknown. Patients with mutations in α6 containing integrins not only develop epidermolysis bullosa, but also have abnormalities in the kidney collecting system. In this study, we show that selectively deleting the α6 or β4 integrin subunits at the initiation of ureteric bud development in mice does not affect morphogenesis. However, the collecting system becomes dilated and dysmorphic as the mice age. The collecting system in both null genotypes was also highly susceptible to unilateral ureteric obstruction injury with evidence of excessive tubule dilatation and epithelial cell apoptosis. Mechanistically, integrin α6-null collecting duct cells are unable to withstand high mechanical force when adhered to laminin. Thus, we conclude that α6 integrins are important for maintaining the integrity of the kidney collecting system by enhancing tight adhesion of the epithelial cells to the basement membrane. These data give a mechanistic explanation for the association between kidney collecting system abnormalities in patients and epidermolysis bullosa.

Highly sensitive detection of invasive lung cancer cells by novel antibody against amino-terminal domain of laminin γ2 chain

The laminin γ2 chain, a subunit of laminin-332 (α3β3γ2), is a molecular marker for invasive cancer cells, but its pathological roles in tumor progression remain to be clarified. It was recently found that the most N-terminal, domain V (dV) of γ2 chain has activities to bind CD44 and stimulate tumor cell migration and vascular permeability. In the present study, we prepared a mAb recognizing γ2 dV. Immunoblotting with this antibody, for the first time, showed that proteolytic fragments containing dV in a range of 15-80 kDa were highly produced in various human cancer cell lines and lung cancer tissues. In immunohistochemistry of adenocarcinomas and squamous cell carcinomas of the lung, this antibody immunostained the cytoplasm of invasive tumor cells and adjacent stroma much more strongly than a widely used antibody recognizing the C-terminal core part of the processed γ2 chain. This suggests that the dV fragments are highly accumulated in tumor cells and stroma compared to the processed γ2 protein. The strong tumor cell staining with the dV antibody correlated with the tumor malignancy grade. We also found that the laminin β3 and α3 chains were frequently overexpressed in tumor cells and tumor stroma, respectively. The cytoplasmic dV detection was especially prominent in tumor cells infiltrating stroma, but low in the cells surrounded by basement membranes, suggesting that the active tumor-stroma interaction is critical for the aberrant γ2 expression. The present study suggests important roles of laminin γ2 N-terminal fragments in tumor progression.

Role of epithelial to mesenchymal transition in hepatocellular carcinoma

The epithelial to mesenchymal transition (EMT) is a multistep biological process whereby epithelial cells change in plasticity by transient de-differentiation into a mesenchymal phenotype. EMT and its reversal, mesenchymal to epithelial transition (MET), essentially occur during embryogenetic morphogenesis and have been increasingly described in fibrosis and cancer during the last decade. In carcinoma progression, EMT plays a crucial role in early steps of metastasis when cells lose cell-cell contacts due to ablation of E-cadherin and acquire increased motility to spread into surrounding or distant tissues. Epithelial plasticity has become a hot issue in hepatocellular carcinoma (HCC), as strong inducers of EMT such as transforming growth factor-β are able to orchestrate both fibrogenesis and carcinogenesis, showing rising cytokine levels in cirrhosis and late stage HCC. In this review, we consider the significance of EMT-MET in malignant hepatocytes as well as changes in the plasticity of hepatic stellate cells for cellular heterogeneity of HCC, and further aim at explaining the current limiting insights into EMT by snapshot analyses of HCC tissues. Recent advances in the identification of clinically relevant mechanisms that impinge on important EMT-transcription factors, as well as on miRNAs causing EMT signatures and HCC progression are highlighted. In addition, we draw particular attention to framing EMT in the context of potential clinical relevance for HCC patients. We conclude that some aspects of EMT are still elusive and further studies are required to better link the clinical management of HCC with biomarkers and targeted therapies related to EMT.

SPR imaging biosensor for determination of laminin-5 as a potential cancer marker in biological material

A new method for the selective determination of laminin-5 concentration using a biosensor and surface plasmon resonance imaging (SPRI) technique is presented. A biosensor based on the specific interaction of laminin-5 with rabbit polyclonal antibody was constructed. The analytically useful dynamic response range of the biosensor is between 0.014 and 0.1 ng mL(-1). The detection limit is 4 pg mL(-1). The potential influence of interferences on the SPRI signal was investigated, and the high selectivity of the biosensor was confirmed. In order to demonstrate the potential application of the biosensor, laminin-5 concentration in blood plasma was determined. The results were compared with the laminin-5 concentration obtained by the commercial enzyme-linked immunosorbent assay (ELISA) kit. A comparison of results from healthy donors obtained by SPRI measurement and ELISA indicates that they are close and shows good agreement with the data reported in the literature. The plasma samples of bladder cancer patients gave higher concentration measured with specific biosensor than by ELISA assay. The study shows the clear difference in concentration of laminin-5 in healthy humans and patients with bladder cancer. Extensive clinical studies using the newly developed method can result in an increase in the use of laminin-5 as a potential cancer marker.

Suspension survival mediated by PP2A-STAT3-Col XVII determines tumour initiation and metastasis in cancer stem cells

Targeting tumour-initiating cells (TICs) would lead to new therapies to cure cancer. We previously demonstrated that TICs have the capacity to survive under suspension conditions, while other cells undergo anoikis. Here we show that TICs exhibit increased phosphorylation levels of S727STAT3 because of PP2A inactivation. Collagen 17 gene expression is upregulated in a STAT3-dependent manner, which also stabilizes laminin 5 and engages cells to form hemidesmosome-like junctions in response. Blocking the PP2A-S727STAT3-collagen 17 pathway inhibits the suspension survival of TICs and their ability to form tumours in mice, while activation of the same pathway increases the suspension survival and tumour-initiation capacities of bulk cancer cells. The S727STAT3 phosphorylation levels correlate with collagen 17 expression in colon tumour samples, and correlate inversely with survival. Finally, this signalling axis enhances the ability of TIC to form tumours in mouse models of malignant lung cancer pleural effusion and spontaneous colon cancer metastasis.

Mechanism of irradiation-induced mammary cancer metastasis: A role for SAP-dependent Mkl1 signaling

Radiotherapy is a standard treatment after conservative breast cancer surgery. However, cancers relapsing within a previously irradiated area have an increased probability to metastasize. The mechanisms responsible for this aggressiveness remain unclear. Here, we used the clinically relevant 4T1 breast cancer model mimicking aggressive local relapse after radiotherapy to identify differences between tumors grown in untreated versus preirradiated mammary glands. Tumors grown within preirradiated beds were highly enriched in transcripts encoding collagens and other proteins building or modifying the extracellular matrix, such as laminin‐332, tenascins, lysyl oxidases and matrix metalloproteinases. Type I collagen, known to directly contribute to tissue stiffening, and the pro‐metastatic megakaryoblastic leukemia‐1 (Mkl1) target gene tenascin‐C were further investigated. Mammary tissue preirradiation induced Mkl1 nuclear translocation in the tumor cells in vivo, indicating activation of Mkl1 signaling. Transcript profiling of cultured 4T1 cells revealed that the majority of the Mkl1 target genes, including tenascin‐C, required serum response factor (SRF) for their expression. However, application of dynamic strain or matrix stiffness to 4T1 cells converted the predominant SRF/Mkl1 action into SAP domain‐dependent Mkl1 signaling independent of SRF, accompanied by a switch to SAP‐dependent tumor cell migration. 4T1 tumors overexpressing intact Mkl1 became more metastatic within preirradiated beds, while tumors expressing Mkl1 lacking the SAP domain exhibited impaired growth and metastatic spread, and decreased Mkl1 target gene expression. Thus, we identified SAP‐dependent Mkl1 signaling as a previously unrecognized mediator of aggressive progression of mammary tumors locally relapsing after radiotherapy, and provide a novel signaling pathway for therapeutic intervention.

Stroma irradiation results in tumors with increased extracellular matrix deposition.

Irradiation induces Mkl1 nuclear translocation, tumor growth and lung metastases.

Matrix stiffness and cyclic mechanical strain trigger SAP‐dependent Mkl1 signaling.

Strain and irradiation induce SAP‐dependent cell migration and tumor progression.

Radiation‐induced SAP‐dependent Mkl1 action: a new target for breast cancer therapy.

MiR-218 mediates tumorigenesis and metastasis: Perspectives and implications

MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. As a highly conserved miRNA across a variety of species, microRNA-218 (miR-218) was found to play pivotal roles in tumorigenesis and progression. A group of evidence has demonstrated that miR-218 acts as a tumor suppressor by targeting many oncogenes related to proliferation, apoptosis and invasion. In this review, we provide a complex overview of miR-218, including its regulatory mechanisms, known functions in cancer and future challenges as a potential therapeutic target in human cancers.

Collagen XVII expression correlates with the invasion and metastasis of colorectal cancer

Collagen XVII has a well-established role as an adhesion molecule and a cell surface receptor located in the type I hemidesmosome of stratified epithelia. Its ectodomain is constitutively shed from the cell surface and suggested to regulate the adhesion, migration, and signaling of cutaneous epithelial cells. Collagen XVII was not previously thought to be expressed by colon epithelial cells. Immunohistochemical analysis of tissue microarray samples of 141 cases of colorectal carcinoma showed that collagen XVII is expressed in normal human colonic mucosa and colorectal carcinoma. In colorectal carcinoma, increased collagen XVII expression was significantly associated with higher TNM stage. It also correlated with infiltrative growth pattern and tumor budding as well as lymph node and distant metastasis. Increased collagen XVII expression was associated with decreased disease-free and cancer-specific survival. Immunofluorescence staining of collagen XVII and its well-known binding partner laminin γ2 chain demonstrated a partial colocalization in normal and tumor tissue. In vitro, the overexpression of murine collagen XVII promoted the invasion of CaCo-2 colon carcinoma cells through Matrigel (BD Biosciences; Bedford, MA). To conclude, this study reports for the first time the expression of collagen XVII in colon epithelium and the association of increased collagen XVII immunoexpression with poor outcome in colorectal carcinoma.

Transcriptional analysis of left-sided colitis, pancolitis, and ulcerative colitis-associated dysplasia

BACKGROUND

It is unknown why patients with extensive ulcerative colitis (UC) have a higher risk of colorectal cancer compared with patients with left-sided UC. This study characterizes the inflammatory processes in left-sided UC, pancolitis, and UC-associated dysplasia at the transcriptional level to identify potential biomarkers and transcripts of importance for the carcinogenic behavior of chronic inflammation.

METHODS

The Affymetrix GeneChip Human Genome U133 Plus 2.0 was applied on colonic biopsies from UC patients with left-sided UC, pancolitis, dysplasia, and controls. Reverse transcription polymerase chain reaction and immunohistochemistry were performed for validating selected transcripts in the initial cohort and in 2 independent cohorts of patients with UC. Microarray data were analyzed by principal component analysis, and reverse transcription polymerase chain reaction and immunohistochemistry data by the Wilcoxon's rank-sum test.

RESULTS

The principal component analysis results revealed separate clusters for left-sided UC, pancolitis, dysplasia, and controls. Close clustering of dysplastic and pancolitic samples indicated similarities in gene expression. Indeed, 101 and 656 parallel upregulated and downregulated transcripts, respectively, were identified in specimens from dysplasia and pancolitis. Validation of selected transcripts hereof identified insulin receptor alpha (INSRA) and MAP kinase interacting serine/threonine kinase 2 (MKNK2) with an enhanced expression in dysplasia compared with left-sided UC and controls, whereas laminin γ2 (LAMC2) was found with a lower expression in dysplasia compared with the remaining 3 groups.

CONCLUSIONS

This study demonstrates pancolitis and left-sided UC as distinct inflammatory processes at the transcriptional level, and identifies INSRA, MKNK2, and LAMC2 as potential critical transcripts in the inflammation-driven preneoplastic process of UC.

A Comprehensive Review of Dysregulated miRNAs Involved in Cervical Cancer

MicroRNAs(miRNAs) have become the center of interest in oncology. In recent years, various studies have demonstrated that miRNAs regulate gene expression by influencing important regulatory genes and thus are responsible for causing cervical cancer. Cervical cancer being the third most diagnosed cancer among the females worldwide, is the fourth leading cause of cancer related mortality. Prophylactic human papillomavirus (HPV) vaccines and new HPV screening tests, combined with traditional Pap test screening have greatly reduced cervical cancer. Yet, thousands of women continue to be diagnosed with and die of this preventable disease annually. This has necessitated the scientists to ponder over ways of evolving new methods and chalk out novel treatment protocols/strategies. As miRNA deregulation plays a key role in malignant transformation of cervical cancer along with its targets that can be exploited for both prognostic and therapeutic strategies, we have collected and reviewed the role of miRNA in cervical cancer. A systematic search was performed using PubMed for articles that report aberrant expression of miRNA in cervical cancer. The present review provides comprehensive information for 246 differentially expressed miRNAs gathered from 51 published articles that have been implicated in cervical cancer progression. Of these, more than 40 miRNAs have been reported in the literature in several instances signifying their role in the regulation of cancer. We also identified 40 experimentally validated targets, studied the cause of miRNAs dysregulation along with its mechanism and role in different stages of cervical cancer. We also identified and analysed miRNA clusters and their expression pattern in cervical cancer. This review is expected to further enhance our understanding in this field and serve as a valuable reference resource.

Laminins 411 and 421 differentially promote tumor cell migration via α6β1 integrin and MCAM (CD146)

α4-laminins, such as laminins 411 and 421, are mesenchymal laminins expressed by blood and lymphatic vessels and some tumor cells. Laminin-411 promotes migration of leukocytes and endothelial cells, but the effect of this laminin and laminin-421 on tumor cells is poorly understood. In the present study, we demonstrate that laminin-411 and, to a greater extent, laminin-421 significantly promote migration of tumor cells originated from melanomas, gliomas and different carcinomas via α6β1 integrin. In solid-phase binding assays, both laminins similarly bound α6β1 integrin but only laminin-421, among several laminin isoforms, readily bound MCAM (CD146), a cell-surface adhesion molecule strongly associated with tumor progression. Accordingly, a function-blocking mAb to MCAM inhibited tumor cell migration on laminin-421 but not on laminins 411 or 521. In tumor tissues, melanoma cells co-expressed MCAM, laminin α4, β1, β2 and γ1 chains, and integrin α6 and β1 chains. The present data highlight the novel role of α4-laminins in tumor cell migration and identify laminin-421 as a primary ligand for MCAM and a putative mediator of tumor invasion and metastasis.

Amino-terminal fragments of laminin γ2 chain retract vascular endothelial cells and increase vascular permeability

Laminin γ2 (Lmγ2) chain, a subunit of laminin-332, is a typical molecular marker of invading cancer cells, and its expression correlates with poor prognosis of cancer patients. It was previously found that forced expression of Lmγ2 in cancer cells promotes their invasive growth in nude mice. However, the mechanism of the tumor-promoting activity of Lmγ2 remains unknown. Here we investigated the interaction between Lmγ2 and vascular endothelial cells. When treated with an N-terminal proteolytic fragment of γ2 (γ2pf), HUVECs became markedly retracted or shrunken. The overexpression of Lmγ2 or treatment with γ2pf stimulated T-24 bladder carcinoma cells to invade into the HUVEC monolayer and enhanced their transendothelial migration in vitro. Moreover, γ2pf increased endothelial permeability in vitro and in vivo. As the possible mechanisms, γ2pf activated ERK and p38 MAPK but inactivated Akt in HUVECs. Such effects of γ2pf led to prominent actin stress fiber formation in HUVECs, which was blocked by a ROCK inhibitor. In addition, γ2pf induced delocalization of VE-cadherin and β-catenin from the intercellular junction. As possible receptors, γ2pf interacted with heparan sulfate proteoglycans on the surface of HUVECs. Moreover, we localized the active site of γ2pf to the N-terminal epidermal growth factor-like repeat. These data suggest that the interaction between γ2pf and heparan sulfate proteoglycans induces cytoskeletal changes of endothelial cells, leading to the loss of endothelial barrier function and the enhanced transendothelial migration of cancer cells. These activities of Lmγ2 seem to support the aberrant growth of cancer cells.

Matrikine and matricellular regulators of EGF receptor signaling on cancer cell migration and invasion

Cancer invasion is a complex process requiring, among other events, extensive remodeling of the extracellular matrix including deposition of pro-migratory and pro-proliferative moieties. In recent years, it has been described that while invading through matrices cancer cells can change shape and adapt their migration strategies depending on the microenvironmental context. Although intracellular signaling pathways governing the mesenchymal to amoeboid migration shift and vice versa have been mostly elucidated, the extracellular signals promoting these shifts are largely unknown. In this review, we summarize findings that point to matrikines that bind specifically to the EGF receptor as matricellular molecules that enable cancer cell migrational plasticity and promote invasion.

Stress-induced ECM alteration modulates cellular microRNAs that feedback to readjust the extracellular environment and cell behavior

The extracellular environment is a complex entity comprising of the extracellular matrix (ECM) and regulatory molecules. It is highly dynamic and under cell-extrinsic stress, transmits the stressed organism’s state to each individual ECM-connected cell. microRNAs (miRNAs) are regulatory molecules involved in virtually all the processes in the cell, especially under stress. In this review, we analyse how miRNA expression is regulated downstream of various signal transduction pathways induced by changes in the extracellular environment. In particular, we focus on the muscular dystrophy-associated cell adhesion molecule dystroglycan capable of signal transduction. Then we show how exactly the same miRNAs feedback to regulate the extracellular environment. The ultimate goal of this bi-directional signal transduction process is to change cell behavior under cell-extrinsic stress in order to respond to it accordingly.

Tumour-suppressive microRNA-29s inhibit cancer cell migration and invasion by targeting laminin-integrin signalling in head and neck squamous cell carcinoma

Background:

Our recent studies of microRNA (miRNA) expression signatures demonstrated that microRNA-29s (miR-29s; miR-29a/b/c) were significantly downregulated in head and neck squamous cell carcinoma (HNSCC) and were putative tumour-suppressive miRNAs in human cancers. Our aim in this study was to investigate the functional significance of miR-29s in cancer cells and to identify novel miR-29s-mediated cancer pathways and responsible genes in HNSCC oncogenesis and metastasis.

Methods:

Gain-of-function studies using mature miR-29s were performed to investigate cell proliferation, migration and invasion in two HNSCC cell lines (SAS and FaDu). To identify miR-29s-mediated molecular pathways and targets, we utilised gene expression analysis and in silico database analysis. Loss-of-function assays were performed to investigate the functional significance of miR-29s target genes.

Results:

Restoration of miR-29s in SAS and FaDu cell lines revealed significant inhibition of cancer cell migration and invasion. Gene expression data and in silico analysis demonstrated that miR-29s modulated the focal adhesion pathway. Moreover, laminin γ2 (LAMC2) and α6 integrin (ITGA6) genes were candidate targets of the regulation of miR-29s. Luciferase reporter assays showed that miR-29s directly regulated LAMC2 and ITGA6. Silencing of LAMC2 and ITGA6 genes significantly inhibited cell migration and invasion in cancer cells.

Conclusion:

Downregulation of miR-29s was a frequent event in HNSCC. The miR-29s acted as tumour suppressors and directly targeted laminin–integrin signalling. Recognition of tumour-suppressive miRNA-mediated cancer pathways provides new insights into the potential mechanisms of HNSCC oncogenesis and metastasis and suggests novel therapeutic strategies for the disease.

Aberrant expression of laminin γ2 correlates with poor prognosis and promotes invasion in extrahepatic cholangiocarcinoma

BACKGROUND

To investigate the potential role of laminin γ2 and its correlation with prognosis in patients with extrahepatic cholangiocarcinoma (CCA).

MATERIALS AND METHODS

Laminin γ2 expression was evaluated by immunohistochemistry in 72 extrahepatic CCA patients after surgical resection. Knockdown of laminin γ2 was achieved via small interfering RNA transfection in the extrahepatic CCA cell line QBC939.

RESULTS

Thirty-six of 72 extrahepatic CCAs (50%) stained positive for laminin γ2 in two types of patterns: stromal staining (28/72, 39%) and cytoplasmic staining (24/72, 33%). All 16 paracancerous tissue samples showed negative staining. Both stromal and cytoplasmic laminin γ2 expressions correlated with lymph node metastasis. Kaplan-Meier analysis showed that aberrant expression of laminin γ2 correlated with poor overall survival and early recurrence. Cox regression analysis further demonstrated that laminin γ2 expression was a significant independent predictor of poor overall survival and early recurrence. Immunofluorescence staining revealed cytoplasmic expression of laminin γ2 in QBC939 cells. Knockdown of laminin γ2 significantly reduced QBC939 cell invasion and migration.

CONCLUSIONS

Aberrant expression of laminin γ2 correlates with poor prognosis and promotes invasion in extrahepatic CCA.