CD151-α3β1 integrin complexes are prognostic markers of glioblastoma and cooperate with EGFR to drive tumor cell motility and invasion

Impact of CD151 overexpression on prognosis and therapy in non-small cell lung cancer patients lacking EGFR mutations

This study investigates CD151, a protein linked to cancer progression, in non-small cell lung cancer (NSCLC) patients without epidermal growth factor receptor (EGFR) mutations. These patients often have limited treatment options. The study used retrospective analysis to examine 157 adenocarcinoma biopsy specimens and 199 patient cases from The Cancer Genome Atlas, correlating CD151 expression with patient survival. Cellular studies revealed that CD151 interacts with EGFR, influencing epidermal growth factor (EGF)-induced cell proliferation and the effectiveness of the EGFR inhibitor, erlotinib. A strong association was found between CD151 expression and EGFR mutation status. High CD151 expression in the absence of EGFR mutations is correlated with poorer survival outcomes. Biological assays showed that CD151 colocalizes and associates with EGFR, playing a crucial role in regulating EGF-induced cell proliferation via the AKT and ERK1/2 pathways. Importantly, CD151 expression was found to influence the anti-proliferative effects of the EGFR tyrosine kinase inhibitor, erlotinib. High CD151 expression, in the absence of EGFR mutations, was associated with poorer survival outcomes. It could serve as a potential prognostic marker and influence cellular responses to EGFR-targeted treatments. This study highlights CD151 as a potential novel target for therapeutic intervention in NSCLC, especially in populations lacking EGFR mutations.

Glioma actively orchestrate a self-advantageous extracellular matrix to promote recurrence and progression

The intricate interplay between cancer cells and their surrounding microenvironment has emerged as a critical factor driving the aggressive progression of various malignancies, including gliomas. Among the various components of this dynamic microenvironment, the extracellular matrix (ECM) holds particular significance. Gliomas, intrinsic brain tumors that originate from neuroglial progenitor cells, have the remarkable ability to actively reform the ECM, reshaping the structural and biochemical landscape to their advantage. This phenomenon underscores the adaptability and aggressiveness of gliomas, and highlights the intricate crosstalk between tumor cells and their surrounding matrix.In this review, we delve into how glioma actively regulates glioma ECM to organize a favorable microenvironment for its survival, invasion, progression and therapy resistance. By unraveling the intricacies of glioma-induced ECM remodeling, we gain valuable insights into potential therapeutic strategies aimed at disrupting this symbiotic relationship and curbing the relentless advance of gliomas within the brain.

mRNA markers for survival prediction in glioblastoma multiforme patients: a systematic review with bioinformatic analyses

BACKGROUND

Glioblastoma multiforme (GBM) is a type of fast-growing brain glioma associated with a very poor prognosis. This study aims to identify key genes whose expression is associated with the overall survival (OS) in patients with GBM.

METHODS

A systematic review was performed using PubMed, Scopus, Cochrane, and Web of Science up to Journey 2024. Two researchers independently extracted the data and assessed the study quality according to the New Castle Ottawa scale (NOS). The genes whose expression was found to be associated with survival were identified and considered in a subsequent bioinformatic study. The products of these genes were also analyzed considering protein-protein interaction (PPI) relationship analysis using STRING. Additionally, the most important genes associated with GBM patients' survival were also identified using the Cytoscape 3.9.0 software. For final validation, GEPIA and CGGA (mRNAseq_325 and mRNAseq_693) databases were used to conduct OS analyses. Gene set enrichment analysis was performed with GO Biological Process 2023.

RESULTS

From an initial search of 4104 articles, 255 studies were included from 24 countries. Studies described 613 unique genes whose mRNAs were significantly associated with OS in GBM patients, of which 107 were described in 2 or more studies. Based on the NOS, 131 studies were of high quality, while 124 were considered as low-quality studies. According to the PPI network, 31 key target genes were identified. Pathway analysis revealed five hub genes (IL6, NOTCH1, TGFB1, EGFR, and KDR). However, in the validation study, only, the FN1 gene was significant in three cohorts.

CONCLUSION

We successfully identified the most important 31 genes whose products may be considered as potential prognosis biomarkers as well as candidate target genes for innovative therapy of GBM tumors.

Ceramide Is Involved in Temozolomide Resistance in Human Glioblastoma U87MG Overexpressing EGFR

Glioblastoma multiforme (GBM) is the most frequent and deadly brain tumor. Many sphingolipids are crucial players in the regulation of glioma cell growth as well as in the response to different chemotherapeutic drugs. In particular, ceramide (Cer) is a tumor suppressor lipid, able to induce antiproliferative and apoptotic responses in different types of tumors including GBM, most of which overexpress the epidermal growth factor receptor variant III (EGFRvIII). In this paper, we investigated whether Cer metabolism is altered in the U87MG human glioma cell line overexpressing EGFRvIII (EGFR+ cells) to elucidate their possible interplay in the mechanisms regulating GBM survival properties and the response to the alkylating agent temozolomide (TMZ). Notably, we demonstrated that a low dose of TMZ significantly increases Cer levels in U87MG cells but slightly in EGFR+ cells (sensitive and resistant to TMZ, respectively). Moreover, the inhibition of the synthesis of complex sphingolipids made EGFR+ cells sensitive to TMZ, thus involving Cer accumulation/removal in TMZ resistance of GBM cells. This suggests that the enhanced resistance of EGFR+ cells to TMZ is dependent on Cer metabolism. Altogether, our results indicate that EGFRvIII expression confers a TMZ-resistance phenotype to U87MG glioma cells by counteracting Cer increase.

Identifying cancer driver genes using a two-stage random walk with restart on a gene interaction network

Cancer development and progression are significantly influenced by cancer driver genes. Understanding cancer driver genes and their mechanisms of action is essential for developing effective cancer treatments. As a result, identifying driver genes is important for drug development, cancer diagnosis, and treatment. Here, we present an algorithm to discover driver genes based on the two-stage random walk with restart (RWR), and the modified method for calculating the transition probability matrix in random walk algorithm. First, we performed the first stage of RWR on the whole gene interaction network, in which we employ a new method for calculating the transition probability matrix and extracted the subnetwork based on nodes that had a high correlation with the seed nodes. The subnetwork was then applied to the second stage of RWR and the nodes were re-ranked in the subnetwork. Our approach outperformed existing methods in identifying driver genes. The outcome of the effect of three gene interaction networks, two rounds of random walk, and the seed nodes' sensitivity were all compared at the same time. In addition, we identified several potential driver genes, some of which are involved in driving cancer development. Overall, our method is efficient in various cancer types, significantly outperforms existing methods, and can identify possible driver genes.

Targeting fatty acid oxidation via Acyl-CoA binding protein hinders glioblastoma invasion

The diffuse nature of Glioblastoma (GBM) tumors poses a challenge to current therapeutic options. We have previously shown that Acyl-CoA Binding Protein (ACBP, also known as DBI) regulates lipid metabolism in GBM cells, favoring fatty acid oxidation (FAO). Here we show that ACBP downregulation results in wide transcriptional changes affecting invasion-related genes. In vivo experiments using patient-derived xenografts combined with in vitro models demonstrated that ACBP sustains GBM invasion via binding to fatty acyl-CoAs. Blocking FAO mimics ACBP^KD-induced immobility, a cellular phenotype that can be rescued by increasing FAO rates. Further investigation into ACBP-downstream pathways served to identify Integrin beta-1, a gene downregulated upon inhibition of either ACBP expression or FAO rates, as a mediator for ACBP's role in GBM invasion. Altogether, our findings highlight a role for FAO in GBM invasion and reveal ACBP as a therapeutic vulnerability to stall FAO and subsequent cell invasion in GBM tumors.

Cellular senescence in malignant cells promotes tumor progression in mouse and patient Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, yet it remains refractory to systemic therapy. Elimination of senescent cells has emerged as a promising new treatment approach against cancer. Here, we investigated the contribution of senescent cells to GBM progression. Senescent cells are identified in patient and mouse GBMs. Partial removal of p16^Ink4a-expressing malignant senescent cells, which make up less than 7 % of the tumor, modifies the tumor ecosystem and improves the survival of GBM-bearing female mice. By combining single cell and bulk RNA sequencing, immunohistochemistry and genetic knockdowns, we identify the NRF2 transcription factor as a determinant of the senescent phenotype. Remarkably, our mouse senescent transcriptional signature and underlying mechanisms of senescence are conserved in patient GBMs, in whom higher senescence scores correlate with shorter survival times. These findings suggest that senolytic drug therapy may be a beneficial adjuvant therapy for patients with GBM.

Inter and intra-tumor heterogeneity of paediatric type diffuse high-grade gliomas revealed by single-cell mass cytometry

Paediatric-type diffuse high-grade gliomas (PDHGG) are aggressive tumors affecting children and young adults, with no effective treatment. These highly heterogeneous malignancies arise in different sites of the Central Nervous System (CNS), carrying distinctive molecular alterations and clinical outcomes (inter-tumor heterogeneity). Moreover, deep cellular and molecular profiling studies highlighted the coexistence of genetically and phenotypically different subpopulations within the same tumor mass (intra-tumor heterogeneity). Despite the recent advances made in the field, the marked heterogeneity of PDHGGs still impedes the development of effective targeted therapies and the identification of suitable biomarkers. In order to fill the existing gap, we used mass cytometry to dissect PDHGG inter- and intra-heterogeneity. This is one of the most advanced technologies of the "-omics" era that, using antibodies conjugated to heavy metals, allows the simultaneous measurement of more than 40 markers at single-cell level. To this end, we analyzed eight PDHGG patient-derived cell lines from different locational and molecular subgroups. By using a panel of 15 antibodies, directly conjugated to metals or specifically customized to detect important histone variants, significant differences were highlighted in the expression of the considered antigens. The single-cell multiparametric approach realized has deepened our understanding of PDHGG, confirming a high degree of intra- and inter-tumoral heterogeneity and identifying some antigens that could represent useful biomarkers for the specific PDHGG locational or molecular subgroups.

A Comprehensive Prognostic Analysis of Tumor-Related Blood Group Antigens in Pan-Cancers Suggests That SEMA7A as a Novel Biomarker in Kidney Renal Clear Cell Carcinoma

Blood group antigen is a class of heritable antigenic substances present on the erythrocyte membrane. However, the role of blood group antigens in cancer prognosis is still largely unclear. In this study, we investigated the expression of 33 blood group antigen genes and their association with the prognosis of 30 types of cancers in 31,870 tumor tissue samples. Our results revealed that blood group antigens are abnormally expressed in a variety of cancers. The high expression of these antigen genes was mainly related to the activation of the epithelial-mesenchymal transition (EMT) pathway. High expression of seven antigen genes, i.e., FUT7, AQP1, P1, C4A, AQP3, KEL and DARC, were significantly associated with good OS (Overall Survival) in six types of cancers, while ten genes, i.e., AQP1, P1, C4A, AQP3, BSG, CD44, CD151, LU, FUT2, and SEMA7A, were associated with poor OS in three types of cancers. Kidney renal clear cell carcinoma (KIRC) is associated with the largest number (14 genes) of prognostic antigen genes, i.e., CD44, CD151, SEMA7A, FUT7, CR1, AQP1, GYPA, FUT3, FUT6, FUT1, SLC14A1, ERMAP, C4A, and B3GALT3. High expression of SEMA7A gene was significantly correlated with a poor prognosis of KIRC in this analysis but has not been reported previously. SEMA7A might be a putative biomarker for poor prognosis in KIRC. In conclusion, our analysis indicates that blood group antigens may play functional important roles in tumorigenesis, progression, and especially prognosis. These results provide data to support prognostic marker development and future clinical management.

Integrin α3β1 promotes vessel formation of glioblastoma-associated endothelial cells through calcium-mediated macropinocytosis and lysosomal exocytosis

Therapeutic targeting of angiogenesis in glioblastoma has yielded mixed outcomes. Investigation of tumor-associated angiogenesis has focused on the factors that stimulate the sprouting, migration, and hyperproliferation of the endothelial cells. However, little is known regarding the processes underlying the formation of the tumor-associated vessels. To address this issue, we investigated vessel formation in CD31+ cells isolated from human glioblastoma tumors. The results indicate that overexpression of integrin α3β1 plays a central role in the promotion of tube formation in the tumor-associated endothelial cells in glioblastoma. Blocking α3β1 function reduced sprout and tube formation in the tumor-associated endothelial cells and vessel density in organotypic cultures of glioblastoma. The data further suggest a mechanistic model in which integrin α3β1-promoted calcium influx stimulates macropinocytosis and directed maturation of the macropinosomes in a manner that promotes lysosomal exocytosis during nascent lumen formation. Altogether, our data indicate that integrin α3β1 may be a therapeutic target on the glioblastoma vasculature.

Integrin β1 in Pancreatic Cancer: Expressions, Functions, and Clinical Implications

Simple Summary

Pancreatic cancer (PC) is a highly aggressive malignant tumor with an extremely poor prognosis. Early diagnosis and treatment are key to improving the survival rate of PC patients. Emerging studies show that integrins might contribute to the pathogenesis of PC. This review presents the various signaling pathways that are mediated by integrins in PC and emphasizes the multiple functions of integrin β1 in malignant behaviors of PC. It also discusses the clinical significance of integrin β1 as well as integrin β1-based therapy in PC patients.

Abstract

Pancreatic cancer (PC) is characterized by rapid progression and a high mortality rate. The current treatment is still based on surgical treatment, supplemented by radiotherapy and chemotherapy, and new methods of combining immune and molecular biological treatments are being explored. Despite this, the survival rate of PC patients is still very disappointing. Therefore, clarifying the molecular mechanism of PC pathogenesis and developing precisely targeted drugs are key to improving PC prognosis. As the most common β subunit of the integrin family, integrin β1 has been proved to be closely related to the vascular invasion, distant metastasis, and survival of PC patients, and treatment targeting integrin β1 in PC has gained initial success in animal models. In this review, we summarize the various signaling pathways by which integrins are involved in PC, focusing on the roles of integrin β1 in the malignant behaviors of PC. Additionally, recent studies regarding the feasibility of integrin β1 as a diagnostic and prognostic biomarker in PC are also discussed. Finally, we present the progress of several integrin β1-based clinical trials to highlight the potential of integrin β1 as a target for personalized therapy in PC.

Integrin α3/α6 and αV are implicated in ADAM15-activated FAK and EGFR signalling pathway individually and promote non-small-cell lung cancer progression

Disintegrin-metalloproteinase 15(ADAM15), a member of disintegrin metalloproteinases (ADAMs), plays important roles in various cancer types. However, the underlying ADAM15 functioning in lung cancer is still unclear. In the present study, we find that ADAM15 regulates the epidermal growth factor receptor/focal adhesion kinase (EGFR/FAK) signalling pathway by interactions with integrins. Integrin αV is involved in ADAM15-mediated FAK signalling. Further, we find that ADAM15 and CD151 were co-expressed, and the presence of ADAM15 affected the integrin α3/α6-related EGFR signalling pathway by cooperating with CD151. In addition, we also prove the effect of ADAM15 on proliferation in nude mice. Finally, we show that ADAM15 is a direct target of miR-204-5p by luciferase reporter assays, qRT-PCR and western blot analyses. Our findings provide molecular and cellular evidence that ADAM15 promotes cell proliferation and metastasis in NSCLC, which might provide a potential target for NSCLC treatment.

Tetraspanin 7 promotes osteosarcoma cell invasion and metastasis by inducing EMT and activating the FAK-Src-Ras-ERK1/2 signaling pathway

Background

Tetraspanins are members of the 4-transmembrane protein superfamily (TM4SF) that function by recruiting many cell surface receptors and signaling proteins into tetraspanin-enriched microdomains (TEMs) that play vital roles in the regulation of key cellular processes including adhesion, motility, and proliferation. Tetraspanin7 (Tspan7) is a member of this superfamily that plays documented roles in hippocampal neurogenesis, synaptic transmission, and malignant transformation in certain tumor types. How Tspan7 influences the onset or progression of osteosarcoma (OS), however, remains to be defined. Herein, this study aimed to explore the relationship between Tspan7 and the malignant progression of OS, and its underlying mechanism of action.

Methods

In this study, the levels of Tspan7 expression in human OS cell lines were evaluated via qRT-PCR and western blotting. The effect of Tspan7 on proliferation was examined using CCK-8 and colony formation assays, while metastatic role of Tspan7 was assessed by functional assays both in vitro and in vivo. In addition, mass spectrometry and co-immunoprecipitation were performed to verify the interaction between Tspan7 and β1 integrin, and western blotting was used to explore the mechanisms of Tspan7 in OS progresses.

Results

We found that Tspan7 is highly expressed in primary OS tumors and OS cell lines. Downregulation of Tspan7 significantly suppressed OS growth, metastasis, and attenuated epithelial-mesenchymal transition (EMT), while its overexpression had the opposite effects in vitro. Furthermore, it exhibited reduced OS pulmonary metastases in Tspan7-deleted mice comparing control mice in vivo. Additionally, we proved that Tspan7 interacted with β1 integrin to facilitate OS metastasis through the activation of integrin-mediated downstream FAK-Src-Ras-ERK1/2 signaling pathway.

Conclusion

In summary, this study demonstrates for the first time that Tspan7 promotes OS metastasis via interacting with β1 integrin and activating the FAK-Src-Ras-ERK1/2 pathway, which could provide rationale for a new therapeutic strategy for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02591-1.

Tumor Microenvironment in Glioma Invasion

A major malignant trait of gliomas is their remarkable infiltration capacity. When glioma develops, the tumor cells have already reached the distant part. Therefore, complete removal of the glioma is impossible. Recently, research on the involvement of the tumor microenvironment in glioma invasion has advanced. Local hypoxia triggers cell migration as an environmental factor. The transcription factor hypoxia-inducible factor (HIF) -1α, produced in tumor cells under hypoxia, promotes the transcription of various invasion related molecules. The extracellular matrix surrounding tumors is degraded by proteases secreted by tumor cells and simultaneously replaced by an extracellular matrix that promotes infiltration. Astrocytes and microglia become tumor-associated astrocytes and glioma-associated macrophages/microglia, respectively, in relation to tumor cells. These cells also promote glioma invasion. Interactions between glioma cells actively promote infiltration of each other. Surgery, chemotherapy, and radiation therapy transform the microenvironment, allowing glioma cells to invade. These findings indicate that the tumor microenvironment may be a target for glioma invasion. On the other hand, because the living body actively promotes tumor infiltration in response to the tumor, it is necessary to reconsider whether the invasion itself is friend or foe to the brain.

Tspan9 Induces EMT and Promotes Osteosarcoma Metastasis via Activating FAK-Ras-ERK1/2 Pathway

Object

At present, there are few effective treatment options available to patients suffering from osteosarcoma (OS). Clarifying the signaling pathways that govern OS oncogenesis may highlight novel approaches to treating this deadly form of cancer. Recent experimental evidence suggests that the transmembrane protein tetraspanin-9 (Tspan9) plays a role in tumor development. This study was thus formulated to assess the molecular role of Tspan9 as a regulator of OS cell metastasis.

Methods

Gene expression in OS cell lines was evaluated via qRT-PCR, while CCK-8, colony formation, Transwell, and wound healing assays were used to explore the in vitro proliferative, invasive, and migratory activities of OS cells. The relationship between Tspan9 and in vivo OS cell metastasis was assessed by injecting these cells into the tail vein of nude mice. Interactions between the Tspan9 and integrin β1 proteins were explored through mass spectrometric and co-immunoprecipitation, and Western blotting to assess the functional mechanisms whereby Tspan9 shapes OS pathogenesis.

Results

Both primary OS tumors and OS cell lines commonly exhibited Tspan9 upregulation, and the knockdown of this tetraspanin suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) activity in OS cells, whereas Tspan9 overexpression resulted in opposite phenotypes. Tumor lung metastasis were significantly impaired in mice implanted with HOS cells in which Tspan9 was downregulated as compared to mice implanted with control HOS cells. Tspan9 was also found to interact with β1 integrin and to contribute to OS metastasis via the amplification of integrin-mediated downstream FAK/Ras/ERK1/2 signaling pathway.

Conclusion

These data suggest that Tspan9 can serve as a promising therapeutic target in OS.

The role of GTPase-activating protein ARHGAP26 in human cancers

Rho GTPases are molecular switches that play an important role in regulating the behavior of a variety of tumor cells. RhoA GTPase-activating protein 26 (ARHGAP26) is a GTPase-activating protein and inhibits the activity of Rho GTPases by promoting the hydrolytic ability of Rho GTPases. It also affects tumorigenesis and progression of various tumors through several methods, including formation of abnormal fusion genes and circular RNA. This review summarizes the biological functions and molecular mechanisms of ARHGAP26 in different tumors, proposes the potential clinical value of ARHGAP26 in cancer treatment, and discusses current issues that need to be addressed.

Expression Analysis of α5 Integrin Subunit Reveals Its Upregulation as a Negative Prognostic Biomarker for Glioblastoma

Integrin α5β1 was suggested to be involved in glioblastoma (GBM) aggressiveness and treatment resistance through preclinical studies and genomic analysis in patients. However, further protein expression data are still required to confirm this hypothesis. In the present study, we investigated by immunofluorescence the expression of integrin α5 and its prognostic impact in a glioblastoma series of patients scheduled to undergo the Stupp protocol as first-line treatment for GBM. The integrin α5 protein expression level was estimated in each tumor by the mean fluorescence intensity (MFI) and allowed us to identify two subpopulations showing either a high or low expression level. The distribution of patients in both subpopulations was not significantly different according to age, gender, recursive partitioning analysis (RPA) prognostic score, molecular markers or surgical and medical treatment. A high integrin α5 protein expression level was associated with a high risk of recurrence (HR = 1.696, 95% CI 1.031-2.792, p = 0.0377) and reduced overall survival (OS), even more significant in patients who completed the Stupp protocol (median OS: 15.6 vs. 22.8 months; HR = 2.324; 95% CI 1.168-4.621, p = 0.0162). In multivariate analysis, a high integrin α5 protein expression level was confirmed as an independent prognostic factor in the subpopulation of patients who completed the temozolomide-based first-line treatment for predicting OS over age, extent of surgery, RPA score and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation (p = 0.029). In summary, for the first time, our study validates that a high integrin α5 protein expression level is associated with poor prognosis in GBM and confirms its potential as a therapeutic target implicated in the Stupp protocol resistance.

Therapeutic targeting of membrane-associated proteins in central nervous system tumors

The activity of the most complex system, the central nervous system (CNS) is profoundly regulated by a huge number of membrane-associated proteins (MAP). A minor change stimulates immense chemical changes and the elicited response is organized by MAP, which acts as a receptor of that chemical or channel enabling the flow of ions. Slight changes in the activity or expression of these MAPs lead to severe consequences such as cognitive disorders, memory loss, or cancer. CNS tumors are heterogeneous in nature and hard-to-treat due to random mutations in MAPs; like as overexpression of EGFRvIII/TGFβR/VEGFR, change in adhesion molecules α5β3 integrin/SEMA3A, imbalance in ion channel proteins, etc. Extensive research is under process for developing new therapeutic approaches using these proteins such as targeted cytotoxic radiotherapy, drug-delivery, and prodrug activation, blocking of receptors like GluA1, developing viral vector against cell surface receptor. The combinatorial approach of these strategies along with the conventional one might be more potential. Henceforth, our review focuses on in-depth analysis regarding MAPs aiming for a better understanding for developing an efficient therapeutic approach for targeting CNS tumors.

Extracellular Sphingosine-1-Phosphate Downstream of EGFR Increases Human Glioblastoma Cell Survival

Sphingosine-1-phosphate (S1P) is a crucial mediator involved in the progression of different cancers, including glioblastoma multiforme (GBM), the most frequent and deadly human brain tumor, characterized by extensive invasiveness and rapid cell growth. Most of GBMs overexpress the epidermal growth factor receptor (EGFR), and we investigated the possible link between S1P and EGFR signaling pathways, focusing on its role in GBM survival, using the U87MG human cell line overexpressing EGFR (EGFR+). We previously demonstrated that EGFR+ cells have higher levels of extracellular S1P and increased sphingosine kinase-1 (SK1) activity than empty vector expressing cells. Notably, we demonstrated that EGFR+ cells are resistant to temozolomide (TMZ), the standard chemotherapeutic drug in GBM treatment, and the inhibition of SK1 or S1P receptors made EGFR+ cells sensitive to TMZ; moreover, exogenous S1P reverted this effect, thus involving extracellular S1P as a survival signal in TMZ resistance in GBM cells. In addition, both PI3K/AKT and MAPK inhibitors markedly reduced cell survival, suggesting that the enhanced resistance to TMZ of EGFR+ cells is dependent on the increased S1P secretion, downstream of the EGFR-ERK-SK1-S1P pathway. Altogether, our study provides evidence of a functional link between S1P and EGFR signaling pathways enhancing the survival properties of GBM cells.

CD151 drives cancer progression depending on integrin α3β1 through EGFR signaling in non-small cell lung cancer

Background

Tetraspanins CD151, a transmembrane 4 superfamily protein, has been identified participating in the initiation of a variety of cancers. However, the precise function of CD151 in non-small cell lung cancer (NSCLC) remains unclear. Here, we addressed the pro-tumoral role of CD151 in NSCLC by targeting EGFR/ErbB2 which favors tumor proliferation, migration and invasion.

Methods

First, the mRNA expression levels of CD151 in NSCLC tissues and cell lines were measured by RT-PCR. Meanwhile, CD151 and its associated proteins were analyzed by western blotting. The expression levels of CD151 in NSCLC samples and its paired adjacent lung tissues were then verified by Immunohistochemistry. The protein interactions are evaluated by co-immunoprecipitation. Flow cytometry was applied to cell cycle analysis. CCK-8, EdU Incorporation, and clonogenic assays were used to analyze cell viability. Wound healing, transwell migration, and matrigel invasion assays were utilized to assess the motility of tumor cells. To investigate the role of CD151 in vivo, lung carcinoma xenograft mouse model was applied.

Results

High CD151 expression was identified in NSCLC tissues and cell lines, and its high expression was significantly associated with poor prognosis of NSCLC patients. Further, knockdown of CD151 in vitro inhibited tumor proliferation, migration, and invasion. Besides, inoculation of nude mice with CD151-overexpressing tumor cells exhibited substantial tumor proliferation compared to that in control mice which inoculated with vector-transfected tumor cells. Noteworthy, we found that overexpression of CD151 conferred cell migration and invasion by interacting with integrins. We next sought to demonstrate that CD151 regulated downstream signaling pathways via activation of EGFR/ErbB2 in NSCLC cells. Therefore, we infer that CD151 probably affects the sensitivity of NSCLC in response to anti-cancer drugs.

Conclusions

Based on these results, we demonstrated a new mechanism of CD151-mediated tumor progression by targeting EGFR/ErbB2 signaling pathway, by which CD151 promotes NSCLC proliferation, migration, and invasion, which may considered as a potential target of NSCLC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01998-4.

Mechanisms of Invasion in Glioblastoma: Extracellular Matrix, Ca2+ Signaling, and Glutamate

Glioblastoma (GBM) is the most common and malignant form of primary brain tumor with a median survival time of 14–16 months in GBM patients. Surgical treatment with chemotherapy and radiotherapy may help increase survival by removing GBM from the brain. However, complete surgical resection to eliminate GBM is almost impossible due to its high invasiveness. When GBM cells migrate to the brain, they interact with various cells, including astrocytes, neurons, endothelial cells, and the extracellular matrix (ECM). They can also make their cell body shrink to infiltrate into narrow spaces in the brain; thereby, they can invade regions of the brain and escape from surgery. Brain tumor cells create an appropriate microenvironment for migration and invasion by modifying and degrading the ECM. During those processes, the Ca²⁺ signaling pathway and other signaling cascades mediated by various ion channels contribute mainly to gene expression, motility, and invasion of GBM cells. Furthermore, GBM cells release glutamate, affecting migration via activation of ionotropic glutamate receptors in an autocrine manner. This review focuses on the cellular mechanisms of glioblastoma invasion and motility related to ECM, Ca²⁺ signaling, and glutamate. Finally, we discuss possible therapeutic interventions to inhibit invasion by GBM cells.

Expression Profiling of Glioblastoma Cell Lines Reveals Novel Extracellular Matrix-Receptor Genes Correlated With the Responsiveness of Glioma Patients to Ionizing Radiation

Glioblastoma (GBM) is the most lethal and frequent type of brain tumor, leading patients to death in approximately 14 months after diagnosis. GBM treatment consists in surgical removal followed by radio and chemotherapy. However, tumors commonly relapse and the treatment promotes only a slight increase in patient survival. Thus, uncovering the cellular mechanisms involved in GBM resistance is of utmost interest, and the use of cell lines has been shown to be an extremely important tool. In this work, the exploration of RNAseq data from different GBM cell lines revealed different expression signatures, distinctly correlated with the behavior of GBM cell lines regarding proliferation indexes and radio-resistance. U87MG and U138MG cells, which presented expressively reduced proliferation and increased radio-resistance, showed a particular expression signature encompassing enrichment in many extracellular matrix (ECM) and receptor genes. Contrasting, U251MG and T98G cells, that presented higher proliferation and sensibility to radiation, exhibited distinct signatures revealing consistent enrichments for DNA repair processes and although several genes from the ECM-receptor pathway showed up-regulation, enrichments for this pathway were not detected. The ECM-receptor is a master regulatory pathway that is known to impact several cellular processes including: survival, proliferation, migration, invasion, and DNA damage signaling and repair, corroborating the associations we found. Furthermore, searches to The Cancer Genome Atlas (TCGA) repository revealed prognostic correlations with glioma patients for the majority of genes highlighted in the signatures and led to the identification of 31 ECM-receptor genes individually correlated with radiation responsiveness. Interestingly, we observed an association between the number of upregulated genes and survivability greater than 5 years after diagnosis, where almost all the patients that presented 21 or more upregulated genes were deceased before 5 years. Altogether our findings suggest the clinical relevance of ECM-receptor genes signature found here for radiotherapy decision and as biomarkers of glioma prognosis.

The Context-Dependent Impact of Integrin-Associated CD151 and Other Tetraspanins on Cancer Development and Progression: A Class of Versatile Mediators of Cellular Function and Signaling, Tumorigenesis and Metastasis

Simple Summary

Tetraspanins are a family of molecules abundantly expressed on the surface of normal or tumor cells. They have been implicated in recruiting or sequestering key molecular regulators of malignancy of a variety of human cancers, including breast and lung cancers, glioblastoma and leukemia. Yet, how their actions take place remains mysterious due to a lack of traditional platform for molecular interactions. The current review digs into this mystery by examining findings from recent studies of multiple tetraspanins, particularly CD151. The molecular basis for differential impact of tetraspanins on tumor development, progression, and spreading to secondary sites is highlighted, and the complexity and plasticity of their control over tumor cell activities and interaction with their surroundings is discussed. Finally, an outlook is provided regarding tetraspanins as candidate biomarkers and targets for the diagnosis and treatment of human cancer.

Abstract

As a family of integral membrane proteins, tetraspanins have been functionally linked to a wide spectrum of human cancers, ranging from breast, colon, lung, ovarian, prostate, and skin carcinomas to glioblastoma. CD151 is one such prominent member of the tetraspanin family recently suggested to mediate tumor development, growth, and progression in oncogenic context- and cell lineage-dependent manners. In the current review, we summarize recent advances in mechanistic understanding of the function and signaling of integrin-associated CD151 and other tetraspanins in multiple cancer types. We also highlight emerging genetic and epigenetic evidence on the intrinsic links between tetraspanins, the epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), and the Wnt/β-catenin pathway, as well as the dynamics of exosome and cellular metabolism. Finally, we discuss the implications of the highly plastic nature and epigenetic susceptibility of CD151 expression, function, and signaling for clinical diagnosis and therapeutic intervention for human cancer.

Integrin αvβ3 Engagement Regulates Glucose Metabolism and Migration through Focal Adhesion Kinase (FAK) and Protein Arginine Methyltransferase 5 (PRMT5) in Glioblastoma Cells

Metabolic reprogramming promotes glioblastoma cell migration and invasion. Integrin αvβ3 is one of the major integrin family members in glioblastoma multiforme cell surface mediating interactions with extracellular matrix proteins that are important for glioblastoma progression. The role of αvβ3 integrin in regulating metabolic reprogramming and its mechanism of action have not been determined in glioblastoma cells. Integrin αvβ3 engagement with osteopontin promotes glucose uptake and aerobic glycolysis, while inhibiting mitochondrial oxidative phosphorylation. Blocking or downregulation of integrin αvβ3 inhibits glucose uptake and aerobic glycolysis and promotes mitochondrial oxidative phosphorylation, resulting in decreased migration and growth in glioblastoma cells. Pharmacological inhibition of focal adhesion kinase (FAK) or downregulation of protein arginine methyltransferase 5 (PRMT5) blocks metabolic shift toward glycolysis and inhibits glioblastoma cell migration and invasion. These results support that integrin αvβ3 and osteopontin engagement plays an important role in promoting the metabolic shift toward glycolysis and inhibiting mitochondria oxidative phosphorylation in glioblastoma cells. The metabolic shift in cell energy metabolism is coupled to changes in migration, invasion, and growth, which are mediated by downstream FAK and PRMT5 in glioblastoma cells.

Integrin α3β1 Represses Reelin Expression in Breast Cancer Cells to Promote Invasion

Simple Summary

Breast cancer remains the second leading cause of cancer-related deaths in women, and about 1 in 8 women in the United States develops invasive breast cancer in her lifetime. Integrin α3β1 has been linked to breast cancer progression, but mechanisms whereby it promotes tumor invasion remain unclear. The goal of our study was to determine how α3β1 drives invasion, towards exploiting this integrin as a therapeutic target for breast cancer. We found that α3β1 represses the expression of Reelin, a secreted glycoprotein that inhibits invasion and for which loss of expression is associated with poor prognosis in breast cancer. We also show that increased Reelin expression following RNAi-mediated suppression of α3β1 causes a significant decrease in breast cancer cell invasion. Our findings demonstrate a critical role for α3β1 in promoting cell invasion through repression of Reelin, highlighting the potential value of this integrin as a therapeutic target for breast cancer.

Abstract

Integrin α3β1, a cell adhesion receptor for certain laminins, is known to promote breast tumor growth and invasion. Our previous gene microarray study showed that the RELN gene, which encodes the extracellular glycoprotein Reelin, was upregulated in α3β1-deficient (i.e., α3 knockdown) MDA-MB-231 cells. In breast cancer, reduced RELN expression is associated with increased invasion and poor prognosis. In this study we demonstrate that α3β1 represses RELN expression to enhance breast cancer cell invasion. RELN mRNA was significantly increased upon RNAi-mediated α3 knockdown in two triple-negative breast cancer cell lines, MDA-MB-231 and SUM159. Modulation of baseline Reelin levels altered invasive potential, where enhanced Reelin expression in MDA-MB-231 cells reduced invasion, while RNAi-mediated suppression of Reelin in SUM159 cells increased invasion. Moreover, treatment of α3β1-expressing MDA-MB-231 cells with culture medium that was conditioned by α3 knockdown MDA-MB-231 cells led to decreased invasion. RNAi-mediated suppression of Reelin in α3 knockdown MDA-MB-231 cells mitigated this effect of conditioned-medium, identifying secreted Reelin as an inhibitor of cell invasion. These results demonstrate a novel role for α3β1 in repressing Reelin in breast cancer cells to promote invasion, supporting this integrin as a potential therapeutic target.

Implication of integrins α3β1 and α5β1 in invasion and anoikis of SK-Mel-147 human melanoma cells: non-canonical functions of protein kinase Akt

Downregulation of integrins α3β1 and α5β1 strongly decreased cell colony formation and in vitro invasion and markedly enhanced anoikis in SK-Mel-147 human melanoma cells. These modifications were accompanied by a marked increase in the levels of active Akt protein kinase, which indicated it played a non-canonical function in the melanoma cells. Pharmacological inhibition of Akt1, an Akt isozyme, in cells depleted of α3β1 or α5β1 restored their invasive activity, while inhibition of the Akt 2 isoform did not cause a visible effect. Similar to our previous results with the α2β1 integrin, this finding suggested that in signaling pathways initiated by α3β1 and α5β1, the Akt1 isoform performs a non-canonical function in regulating invasive phenotype of melanoma cells. In contrast, when the effects of Akt inhibitors on anoikis of the melanoma cells were compared, the Akt2 isoform demonstrated a non-canonical activity in which Akt2 suppression led to a significant attenuation of apoptosis in cells with downregulated α3β1 or α5β1. Our results were the first evidence that, in the same tumor cells, different integrins can control various manifestations of tumor progression through distinct signaling pathways that are both common to various integrins and specific to a particular receptor.

Epigenetic Input Dictates the Threshold of Targeting of the Integrin-Dependent Pathway in Non-small Cell Lung Cancer

We investigated the therapeutic potential of targeting integrin/FAK-dependent signaling, an adhesion receptor-mediated pathway that has been increasingly linked to non-small cell lung cancer (NSCLC) malignancy. Our analysis of the TCGA cohort showed that a subset of pro-tumorigenic integrins, including α1β1, α2β1, α3β1, α5β1, and α6β4, were frequently amplified or upregulated at the genomic or mRNA level in KRAS or EGFR mutation/overexpression-enriched adenocarcinomas. These alterations appeared complementary, correlated with poor patient survival (p < 0.0072), and were collaborative with KRAS mutation-coupled αv integrins (p < 0.00159). Since integrin/FAK-dependent signaling is tightly coupled with normal human physiology, we sought to use a synthetic lethal-type targeting comprising of VS-6063, a chemical inhibitor of integrin-mediated FAK activity, and A549 cells, which carry a KRAS mutation and EGFR overexpression. Our screening analysis revealed that JQ1 and IBET-762, inhibitors of epigenetic reader BRD4, and LBH589, a pan inhibitor of histone deacetylases (HDACs), exhibited synergy with VS-6063 in mitigating tumor cell viability. This epigenetic link was corroborated by strong effects of additional inhibitors and RNAi-mediated knockdown of FAK and BRD4 or its downstream effector, c-Myc. Low doses of JQ1 (≤0.5 μM) markedly escalated efficacy of VS-6063 across a panel of 10 NSCLC cell lines. This catalyst-like effect is in line with the oncogenic landscape in the TCGA cohort since c-Myc falls downstream of the KRAS and EGFR oncogenes. Mechanistically, co-inhibiting the integrin-FAK and BRD4/c-Myc axes synergistically induced apoptotic cell death and DNA damage response, and impaired stemness-associated tumorsphere formation. These effects were accompanied by a marked inhibition of Akt- and p130Cas/Src-dependent signaling, but not Erk1/2 activity. Meanwhile, JQ1 alone or in combination with VS-6063 attenuated cell-cell adhesion and extracellular matrix (ECM)-dependent cell spreading, which is reminiscent of phenotype induced by malfunctional E-cadherin or integrins. Paradoxically, this phenotypic impact coincided with downregulation of epithelial-mesenchymal transition (EMT)-inducting transcription factor ZEB1 or Snail. Finally, we showed that the effect of the VS-6063/JQ1 combination was nearly equivalent to that of VS-6063 plus Carboplatin or Osimertinib. Overall, our study indicates that the integrin/FAK and BRD4/c-Myc axes cooperatively drive NSCLC virulence, and a co-targeting may provide a line of therapy capable of overcoming EGFR/KRAS-driven malignancy.

Quiescent stem cell marker genes in glioma gene networks are sufficient to distinguish between normal and glioblastoma (GBM) samples

Grade 4 glioma or GBM has poor prognosis and is the most aggressive grade of glioma. Accurate diagnosis and classification of tumor grade is a critical determinant for development of treatment pathway. Extensive genomic sequencing of gliomas, different cell types, brain tissue regions and advances in bioinformatics algorithms, have presented an opportunity to identify molecular markers that can complement existing histology and imaging methods used to diagnose and classify gliomas. ‘Cancer stem cell theory’ purports that a minor population of stem cells among the heterogeneous population of different cell types in the tumor, drive tumor growth and resistance to therapies. However, characterization of stem cell states in GBM and ability of stem cell state signature genes to serve as diagnostic or prognostic molecular markers are unknown. In this work, two different network construction algorithms, Weighted correlation network analysis (WGCNA) and Multiscale Clustering of Geometric Network (MEGENA), were applied on publicly available glioma, control brain and stem cell gene expression RNA-seq datasets, to identify gene network regulatory modules associated with GBM. Both gene network algorithms identified consensus or equivalent modules, HuAgeGBsplit_18 (WGCNA) and c1_HuAgeGBsplit_32/193 (MEGENA), significantly associated with GBM. Characterization of HuAgeGBsplit_18 (WGCNA) and c1_HuAgeGBsplit_32/193 (MEGENA) modules showed significant enrichment of rodent quiescent stem cell marker genes (GSE70696_QNPbyTAP). A logistic regression model built with eight of these quiescent stem cell marker genes (GSE70696_QNPbyTAP) was sufficient to distinguish between control and GBM samples. This study demonstrates that GBM associated gene regulatory modules are characterized by diagnostic quiescent stem cell marker genes, which may potentially be used clinically as diagnostic markers and therapeutic targets in GBM.

Tumor Cell Invasion in Glioblastoma

Glioblastoma (GBM) is a particularly devastating tumor with a median survival of about 16 months. Recent research has revealed novel insights into the outstanding heterogeneity of this type of brain cancer. However, all GBM subtypes share the hallmark feature of aggressive invasion into the surrounding tissue. Invasive glioblastoma cells escape surgery and focal therapies and thus represent a major obstacle for curative therapy. This review aims to provide a comprehensive understanding of glioma invasion mechanisms with respect to tumor-cell-intrinsic properties as well as cues provided by the microenvironment. We discuss genetic programs that may influence the dissemination and plasticity of GBM cells as well as their different invasion patterns. We also review how tumor cells shape their microenvironment and how, vice versa, components of the extracellular matrix and factors from non-neoplastic cells influence tumor cell motility. We further discuss different research platforms for modeling invasion. Finally, we highlight the importance of accounting for the complex interplay between tumor cell invasion and treatment resistance in glioblastoma when considering new therapeutic approaches.

Marine natural compound cyclo(L-leucyl-L-prolyl) peptide inhibits migration of triple negative breast cancer cells by disrupting interaction of CD151 and EGFR signaling

Cyclo (L-Leucyl-L-Prolyl) peptide/CLP is a marine natural metabolite and well recognized as an antimicrobial and antioxidant agent with limited studies on anticancer activity. The current study aims to determine the effect of CLP on migration and growth of triple negative breast cancer cell lines. The anti-growth potential was evaluated by MTT, BrdU and TUNEL assays; DNA damage by γH2AX and Dead green assays; antimigration activity by Boyden chamber invasion and wound healing assays. Interaction of CLP with CD151 was resolved by PatchDock. Effect of CLP on the expression of transmembrane CD151 was evaluated by cell-based ELISA assay. The interaction between CD151 and EGFR was predicted by using FireDoc Web server. Impact of CLP on the interaction of CD151 with EGFR was evaluated by co-immunoprecipitation assay. The effect of CLP on the cell cycle and its controlling proteins was determined by Western blotting. CLP reduced the viability of MDA-MB-231 and MDA-MB-468 TNBC cell lines but not human breast healthy epithelial cell line (MCF-12A) similar to eribulin, standard. CLP also inhibited proliferation; cell cycle and migration. It induced DNA strand breaks, DNA damage, and cell death. It showed the most favorable interactions with CD151 in in silico docking and significantly reduced the expression of membrane-bound CD151 proteins. FireDoc Web study predicted the association between CD151 and EGFR with -29.13 kcal/mol of binding energy. CLP reduced the interaction of CD151 with EGFR along with the expression of cyclin D, CDK4, PAK, RAC1, and P27kiP1. This study concludes that CLP suppresses growth and migration by attenuating cell cycle of TNBC cell lines via EGFR and CD151 signaling. Thus, exploring the EGFR and CD151 signaling pathway targeted by CLP may provide a new approach in the treatment of TNBC.

Overlapping migratory mechanisms between neural progenitor cells and brain tumor stem cells

Neural stem cells present in the subventricular zone (SVZ), the largest neurogenic niche of the mammalian brain, are able to self-renew as well as generate neural progenitor cells (NPCs). NPCs are highly migratory and traverse the rostral migratory stream (RMS) to the olfactory bulb, where they terminally differentiate into mature interneurons. NPCs from the SVZ are some of the few cells in the CNS that migrate long distances during adulthood. The migratory process of NPCs is highly regulated by intracellular pathway activation and signaling from the surrounding microenvironment. It involves modulation of cell volume, cytoskeletal rearrangement, and isolation from compact extracellular matrix. In malignant brain tumors including high-grade gliomas, there are cells called brain tumor stem cells (BTSCs) with similar stem cell characteristics to NPCs but with uncontrolled cell proliferation and contribute to tumor initiation capacity, tumor progression, invasion, and tumor maintenance. These BTSCs are resistant to chemotherapy and radiotherapy, and their presence is believed to lead to tumor recurrence at distal sites from the original tumor location, principally due to their high migratory capacity. BTSCs are able to invade the brain parenchyma by utilizing many of the migratory mechanisms used by NPCs. However, they have an increased ability to infiltrate the tight brain parenchyma and utilize brain structures such as myelin tracts and blood vessels as migratory paths. In this article, we summarize recent findings on the mechanisms of cellular migration that overlap between NPCs and BTSCs. A better understanding of the intersection between NPCs and BTSCs will to provide a better comprehension of the BTSCs' invasive capacity and the molecular mechanisms that govern their migration and eventually lead to the development of new therapies to improve the prognosis of patients with malignant gliomas.

Tspan8 and Tspan8/CD151 knockout mice unravel the contribution of tumor and host exosomes to tumor progression

BACKGROUND

The tetraspanins Tspan8 and CD151 promote metastasis, exosomes (Exo) being suggested to be important in the crosstalk between tumor and host. The contribution of Tspan8 and CD151 to host versus tumor-derived exosome (TEX) activities being not defined, we approached the questions using 3-methylcholanthrene-induced (MCA) tumors from wt, Tspan8ko, CD151ko and Tspan8/CD151 (db)ko mice, implanted into tetraspanin-competent and deficient hosts.

METHODS

Tumor growth and dissemination, hematopoiesis and angiogenesis were surveyed in wild type (wt), Tspan8ko, CD151ko and dbko mice bearing tetraspanin-competent and -deficient MCA tumors. In vitro studies using tumor cells, bone marrow cells (BMC) and endothelial cells (EC) elaborated the mechanism of serum (s)Exo- and TEX-induced target modulation.

RESULTS

Tumors grew in autochthonous and syngeneic hosts differing in Tspan8- and/or CD151-competence. However, Tspan8ko- and/or CD151ko-tumor cell dissemination and settlement in metastatic organs was significantly reduced in the autochthonous host, and less severely in the wt-host. Impaired wt-MCA tumor dissemination in the ko-host confirmed a contribution of host- and tumor-Tspan8/-CD151 to tumor cell dissemination, delivery of sExo and TEX being severely impaired by a Tspan8ko/CD151ko. Coculturing tumor cells, BMC and EC with sExo and TEX revealed minor defects in epithelial mesenchymal transition and apoptosis resistance of ko tumors. Strongly reduced migratory and invasive capacity of Tspan8ko/CD151ko-MCA relies on distorted associations with integrins and CAM and missing Tspan8/CD151-promoted recruitment of proteases. The defects, differing between Tspan8ko- and CD151ko-MCA, were rescued by wt-TEX and, less efficiently Tspan8ko- and CD151ko-TEX. Minor defects in hematopoietic progenitor maturation were based on the missing association of hematopoietic growth factors /- receptors with CD151 and, less pronounced, Tspan8. Rescue of impaired angiogenesis in ko mice by wt-sExo and promotion of angiogenesis by TEX depended on the association of Tspan8 and CD151 with GPCR and RTK in EC and tumor cells.

CONCLUSIONS

Tspan8-/CD151-TEX play central roles in tumor progression. Tspan8-/CD151-sExo and TEX contribute by stimulating angiogenesis. Tspan8 and CD151 fulfill these tasks by associating with function-relevant proteins, the additive impact of Tspan8 and CD151 relying on differences in preferred associations. The distinct Tspan8 and CD151 contributions suggest a blockade of TEX-Tspan8 and -CD151 promising for therapeutic intervention.

Prognostic value of increased integrin-beta 1 expression in solid cancers: a meta-analysis

Integrin-beta 1 (ITGB1) is aberrantly overexpressed or downregulated in solid cancers; however, its prognostic value remains controversial. Therefore, we conducted a meta-analysis to explore whether ITGB1 expression is correlated with overall survival (OS) and the clinicopathological characteristics of patients with solid cancers. We systematically searched the PubMed, Embase, and Web of Science databases for eligible studies published up to June 1, 2017. In total, 22 studies involving 3,666 patients were included. A sensitivity analysis was performed to assess the validity and reliability of the pooled OS. Among the 22 studies, 7 focused on lung cancer, 3 focused on colorectal cancer, 6 focused on breast cancer, 3 involved melanoma, and 3 involved pancreatic cancer. The pooled results showed that high ITGB1 expression was significantly associated with worse OS in lung cancer (pooled hazard ratio [HR]=1.78, 95% CI: 1.19–2.65, p<0.05) and breast cancer (pooled HR=1.88, 95% CI: 1.46–2.42, p<0.01). In addition, a significant association was observed between high ITGB1 expression and disease-free survival in breast cancer (pooled HR=1.63, 95% CI: 1.17–2.25, p<0.001) and pancreatic cancer (pooled HR=2.49, 95% CI: 1.35–4.61, p<0.001). However, high ITGB1 expression was not related to OS in colorectal cancer, pancreatic cancer, or melanoma. The pooled HRs used to evaluate the prognostic value of increased ITGB1 expression in lung cancer, breast cancer, and pancreatic cancer were not significantly altered, which indicates that the pooled results were robust. The results of this study indicate that the prognostic value of decreased ITGB1 expression varies among solid cancers.

MicroRNA-205 targets SMAD4 in non-small cell lung cancer and promotes lung cancer cell growth in vitro and in vivo

Despite advances in diagnosis and treatment, the survival of non-small cell lung cancer (NSCLC) patients remains poor; therefore, improved understanding of the disease mechanism and novel treatment strategies are needed. Downregulation of SMAD4 and dysregulated expression of miR-205 have been reported. However, the relationship between them remains unclear. We investigated the effect of microRNA (miR)-205 on the expression of SMAD4 in NSCLC. Knockdown and overexpression of SMAD4 promoted or suppressed cellular viability and proliferation, and accelerated or inhibited the cell cycle in NSCLC cells, respectively. The 3′-untranslated region (3′-UTR) of SMAD4 was predicted as a target of miR-205. Luciferase assays validated that miR-205 binds directly to the SMAD4 3′-UTR. Protein and mRNA expression analyses confirmed that miR-205 overexpression in NSCLC cells inhibited the expression of SMAD4 mRNA and protein. In human NSCLC tissues, increased miR-205 expression was observed frequently and was inversely correlated with decreased SMAD4 expression. Ectopic expression of miR-205 in NSCLC cells suppressed cellular viability and proliferation, accelerated the cell cycle, and promoted tumor growth of lung carcinoma xenografts in nude mice. Our study showed that miR-205 decreased SMAD4 expression, thus promoting NSCLC cell growth. Our findings highlighted the therapeutic potential of targeting miR-205 in NSCLC treatment.

Cross-talk between sphingosine-1-phosphate and EGFR signaling pathways enhances human glioblastoma cell invasiveness

We show that glioblastoma multiform (GBM) cells overexpressing the constitutively active form of the epidermal growth factor receptor [epidermal growth factor receptor variant III (EGFRvIII) and U87MG human GBM cell line overexpressing EGFRvIII (EGFR+) cells] possess greater invasive properties and have higher levels of extracellular sphingosine-1-phosphate (S1P) and increased sphingosine kinase-1 (SK1) activity than the empty vector-expressing cells. Notably, the inhibition of SK1 or S1P receptors decreases the invasiveness of EGFR+ cells. Moreover, EGFR and MEK1 inhibitors reduce both SK1 activation and cell invasion, suggesting that the enhanced invasiveness observed in the EGFR+ cells depends on the increased S1P secretion, downstream of the EGFRvIII-ERK-SK1-S1P pathway. Altogether, the results of the present study indicate that, in GBM cells, EGFRvIII is connected with the S1P signaling pathway to enhance cell invasiveness and tumor progression.

Tetraspanin CD151 as an emerging potential poor prognostic factor across solid tumors: a systematic review and meta-analysis

Tetraspanin CD151, also known as PETA-3 or SFA-1, has been reported to predict prognosis in various solid tumors. Yet, the results of these studies remained inconclusive. Here, we performed this meta-analysis of relevant studies published on the topic to quantitatively evaluate the clinicopathological significance of CD151 in solid tumors. The relevant articles were identified via searching the PubMed, Web of Science and Embase database. The pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CI) of overall survival (OS) and disease-free survival (DFS) were calculated to evaluate the prognostic value of CD151 expression in patients with solid tumors. A total of 19 studies involving 4, 270 participants were included in the study, we drew the conclusion that CD151 overexpression was associated with statistically significant poor OS (pooled HR = 1.498, 95% CI = 1.346-1.667, P<0.001) and poor DFS (pooled HR = 1.488, 95% CI = 1.314-1.685, P<0.001). Furthermore, the subgroup analysis revealed that the associations between CD151 overexpression and the outcome endpoints (OS or TTP) were significant within the Asian region and European, as well in patients with breast cancer or gastric cancer. Taken together, the incorporative HR showed CD151 overexpression was associated with poor survival in human solid tumors. CD151 could be a valuable prognosis biomarker or a potential therapeutic target of solid tumors.

Identification of Plasma Membrane Glycoproteins Specific to Human Glioblastoma Multiforme Cells Using Lectin Arrays and LC-MS/MS

Glioblastoma, also known as glioblastoma multiforme (GBM), is the most malignant type of brain cancer and has poor prognosis with a median survival of less than one year. While the structural changes of tumor cell surface carbohydrates are known to be associated with invasive behavior of tumor cells, the cell surface glycoproteins to differentiate the low- and high-grade glioma cells can be potential diagnostic markers and therapeutic targets for GBMs. In the present study, lectin arrays consisting of eight lectins were employed to explore cell surface carbohydrate expression patterns on low-grade oligodendroglioma cells (Hs683) and GBM cells (T98G). Griffonia simplicifolia I (GS I) was found to selectively bind to T98G cells and not to Hs683 cells. For identification of the glioblastoma-specific cell surface markers, the glycoproteins from each cell type were captured by a GS I lectin column and analyzed by LC-MS/MS. The identified proteins from the two cell types were quantified using label-free quantitative analysis based on spectral counting. Of cell surface glycoproteins showing significant increases in T98G cells, five proteins were selected for verification of both protein and glycosylation level changes using Western blot and GS I lectin-based immunosorbent assay.

Molecular and Genetic Determinants of Glioma Cell Invasion

A diffusely invasive nature is a major obstacle in treating a malignant brain tumor, "diffuse glioma", which prevents neurooncologists from surgically removing the tumor cells even in combination with chemotherapy and radiation. Recently updated classification of diffuse gliomas based on distinct genetic and epigenetic features has culminated in a multilayered diagnostic approach to combine histologic phenotypes and molecular genotypes in an integrated diagnosis. However, it is still a work in progress to decipher how the genetic aberrations contribute to the aggressive nature of gliomas including their highly invasive capacity. Here we depict a set of recent discoveries involving molecular genetic determinants of the infiltrating nature of glioma cells, especially focusing on genetic mutations in receptor tyrosine kinase pathways and metabolic reprogramming downstream of common cancer mutations. The specific biology of glioma cell invasion provides an opportunity to explore the genotype-phenotype correlation in cancer and develop novel glioma-specific therapeutic strategies for this devastating disease.

C-reactive protein/albumin and neutrophil/lymphocyte ratios and their combination predict overall survival in patients with gastric cancer

Multiple studies have reported the prognostic association of certain inflammatory factors with various types of cancer. The present study assessed the prognostic value of the C-reactive protein (CRP)/albumin (Alb) ratio and the neutrophil/lymphocyte ratio (NLR), separately and in combination, in gastric cancer (GC). A total of 337 cases pathologically diagnosed with gastric adenocarcinoma were retrospectively evaluated. The clinicopathological and prognostic relevance of the CRP/Alb ratio and NLR and their combination were analyzed. The optimal cut-off values of the CRP/Alb ratio and NLR were 0.38 and 3.14, respectively. High CRP/Alb ratio (≥0.38) and NLR (≥3.14) values were associated with increased tumor invasion, more distant metastasis and a more advanced tumor-node-metastasis stage (all P<0.05). In addition, a high NLR value was also associated with increased tumor size (P=0.02). The CRP/Alb ratio (≥0.38/<0.38) and NLR (≥3.14/<3.14) were independent prognostic factors for overall survival time (OS) in GC by multivariate analysis (P=0.005 and P=0.001). Using the CRP/Alb ratio and NLR classification, patients were stratified into three subgroups with different OS time (P<0.001), which were identified as independent prognostic variables in multivariate analysis (P<0.001). The present study demonstrated that the CRP/Alb ratio and NLR were independent prognostic factors for OS in patients with GC. The combination of these indexes was associated with significant prognostic value and may further stratify prognosis.

Interest of integrins targeting in glioblastoma according to tumor heterogeneity and cancer stem cell paradigm: an update

Glioblastomas are malignant brain tumors with dismal prognosis despite standard treatment with surgery and radio/chemotherapy. These tumors are defined by an important cellular heterogeneity and notably contain a particular subpopulation of Glioblastoma-initiating cells, which recapitulate the heterogeneity of the original Glioblastoma. In order to classify these heterogeneous tumors, genomic profiling has also been undertaken to classify these heterogeneous tumors into several subtypes. Current research focuses on developing therapies, which could take into account this cellular and genomic heterogeneity. Among these targets, integrins are the subject of numerous studies since these extracellular matrix transmembrane receptors notably controls tumor invasion and progression. Moreover, some of these integrins are considered as membrane markers for the Glioblastoma-initiating cells subpopulation. We reviewed here integrin expression according to glioblastoma molecular subtypes and cell heterogeneity. We discussed their roles in glioblastoma invasion, angiogenesis, therapeutic resistance, stemness and microenvironment modulations, and provide an overview of clinical trials investigating integrins in glioblastomas. This review highlights that specific integrins could be identified as selective glioblastoma cells markers and that their targeting represents new diagnostic and/or therapeutic strategies.

Knockdown of Long Non-Coding RNA KCNQ1OT1 Restrained Glioma Cells' Malignancy by Activating miR-370/CCNE2 Axis

Accumulating evidence has highlighted the potential role of long non-coding RNAs (lncRNAs) as biomarkers and therapeutic targets in solid tumors. Here, we elucidated the function and possible molecular mechanisms of lncRNA KCNQ1OT1 in human glioma U87 and U251 cells. Quantitative Real-Time polymerase chain reaction (qRT-PCR) demonstrated that KCNQ1OT1 expression was up-regulated in glioma tissues and cells. Knockdown of KCNQ1OT1 exerted tumor-suppressive function in glioma cells. Moreover, a binding region was confirmed between KCNQ1OT1 and miR-370 by dual-luciferase assays. qRT-PCR showed that miR-370 was down-regulated in human glioma tissue and cells. In addition, restoration of miR-370 exerted tumor-suppressive function via inhibiting cell proliferation, migration and invasion, while promoting the apoptosis of human glioma cells. Knockdown of KCNQ1OT1 decreased the expression level of Cyclin E2 (CCNE2) by binding to miR-370. Further, miR-370 bound to CCNE2 3′UTR region and decreased the expression of CCNE2. These results provided a comprehensive analysis of KCNQ1OT1-miR-370-CCNE2 axis in human glioma cells and might provide a novel strategy for glioma treatment.

Inhibition of the integrin/FAK signaling axis and c-Myc synergistically disrupts ovarian cancer malignancy

Integrins, a family of heterodimeric receptors for extracellular matrix, are promising therapeutic targets for ovarian cancer, particularly high-grade serous-type (HGSOC), as they drive tumor cell attachment, migration, proliferation and survival by activating focal adhesion kinase (FAK)-dependent signaling. Owing to the potential off-target effects of FAK inhibitors, disruption of the integrin signaling axis remains to be a challenge. Here, we tackled this barrier by screening for inhibitors being functionally cooperative with small-molecule VS-6063, a phase II FAK inhibitor. From this screening, JQ1, a potent inhibitor of Myc oncogenic network, emerged as the most robust collaborator. Treatment with a combination of VS-6063 and JQ1 synergistically caused an arrest of tumor cells at the G2/M phase and a decrease in the XIAP-linked cell survival. Our subsequent mechanistic analyses indicate that this functional cooperation was strongly associated with the concomitant disruption of activation or expression of FAK and c-Myc as well as their downstream signaling through the PI3K/Akt pathway. In line with these observations, we detected a strong co-amplification or upregulation at genomic or protein level for FAK and c-Myc in a large portion of primary tumors in the TCGA or a local HGSOC patient cohort. Taken together, our results suggest that the integrin–FAK signaling axis and c-Myc synergistically drive cell proliferation, survival and oncogenic potential in HGSOC. As such, our study provides key genetic, functional and signaling bases for the small-molecule-based co-targeting of these two distinct oncogenic drivers as a new line of targeted therapy against human ovarian cancer.

N-Glycosylation of integrin α5 acts as a switch for EGFR-mediated complex formation of integrin α5β1 to α6β4

N-Glycosylation of integrin α5β1 is involved in multiple cell behaviors. We previously reported that the N-glycosylations of the calf domain on integrin α5 (S3–5,10–14) are essential for its inhibitory effect on EGFR signaling in regulating cell proliferation. However, the importance of the individual N-glycosylation and the underlying mechanisms of inhibition remain unclear. Here, we characterize the S3–5,10–14 mutants in detail and found that the N-glycosylation of site-11 (Asn712) is key for cell growth. The restoration of site-11, unlike the other individual sites, significantly suppressed cell growth and EGFR signaling in a manner that was similar to that of wild-type (WT). Mechanistically, this N-glycosylation inhibited the response abilities upon EGF stimulation and EGFR dimerization. Interestingly, we found this N-glycosylation controlled the EGFR complex formation with integrin α5β1 or α6β4; i.e., the loss of site-11 switched EGFR-α5β1 to EGFR-α6β4, which is well known to promote cellular signaling for cell growth. Moreover, the site-11 N-glycan exhibited a more branching structure compared with other sites, which may be required for EGFR-α5β1 formation. Taken together, these data clearly demonstrate that the site-11 N-glycosylation on α5 is most important for its inhibitory effect on EGFR signaling, which may provide a novel regulatory mechanism for crosstalks between integrins and EGFR.

β1 Integrin as a Prognostic and Predictive Marker in Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) displays higher risk of recurrence and distant metastasis. Due to absence of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), TNBC lacks clinically established targeted therapies. Therefore, understanding of the mechanism underlying the aggressive behaviors of TNBC is required for the design of individualized strategies and the elongation of overall survival duration. Here, we supported a positive correlation between β1 integrin and malignant behaviors such as cell migration, invasion, and drug resistance. We found that silencing of β1 integrin inhibited cell migration, invasion, and increased the sensitivity to anti-cancer drug. In contrast, activation of β1 integrin increased cell migration, invasion, and decreased the sensitivity to anti-cancer drug. Furthermore, we found that silencing of β1 integrin abolished Focal adhesion kinese (FAK) mediated cell survival. Overexpression of FAK could restore cisplatin-induced apoptosis in β1 integrin-depleted cells. Consistent to in vitro data, β1 integrin expression was also positively correlated with FAK (p = 0.031) in clinical tissue. More importantly, β1 integrin expression was significantly correlated with patient outcome. In summary, our study indicated that β1 integrin could regulate TNBC cells migration, invasion, drug sensitivity, and be a potential prognostic biomarker in TNBC patient survival.

β1 Integrins as Therapeutic Targets to Disrupt Hallmarks of Cancer

Integrins belong to a large family of αβ heterodimeric transmembrane proteins first recognized as adhesion molecules that bind to dedicated elements of the extracellular matrix and also to other surrounding cells. As important sensors of the cell microenvironment, they regulate numerous signaling pathways in response to structural variations of the extracellular matrix. Biochemical and biomechanical cues provided by this matrix and transmitted to cells via integrins are critically modified in tumoral settings. Integrins repertoire are subjected to expression level modifications, in tumor cells, and in surrounding cancer-associated cells, implicated in tumor initiation and progression as well. As critical players in numerous cancer hallmarks, defined by Hanahan and Weinberg (2011), integrins represent pertinent therapeutic targets. We will briefly summarize here our current knowledge about integrin implications in those different hallmarks focusing primarily on β1 integrins.