Colorectal Cancer Metastases Settle in the Hepatic Microenvironment Through α5β1 Integrin

RGD peptide in cancer targeting: Benefits, challenges, solutions, and possible integrin-RGD interactions

RGD peptide can be found in cell adhesion and signaling proteins, such as fibronectin, vitronectin, and fibrinogen. RGD peptides' principal function is to facilitate cell adhesion by interacting with integrin receptors on the cell surface. They have been intensively researched for use in biotechnology and medicine, including incorporation into biomaterials, conjugation to medicinal molecules or nanoparticles, and labeling with imaging agents. RGD peptides can be utilized to specifically target cancer cells and the tumor vasculature by engaging with these integrins, improving drug delivery efficiency and minimizing adverse effects on healthy tissues. RGD-functionalized drug carriers are a viable option for cancer therapy as this focused approach has demonstrated promise in the future. Writing a review on the RGD peptide can significantly influence how drugs are developed in the future by improving our understanding of the peptide, finding knowledge gaps, fostering innovation, and making drug design easier.

Biological evaluation of integrin α3β1-targeted 68Ga-labeled HEVNPs in HCT 116 colorectal tumor-bearing mice

Integrins are cell surface receptors involved in multiple functions vital for cellular proliferation. Various tumor cells overexpress αβ-integrins, making them ideal biomarkers for diagnostic imaging and tumor-targeted drug delivery. LXY30 is a peptide that can specifically recognize and interact with the integrin α₃β₁, a molecule overexpressed in breast, ovarian and colorectal cancer. Hepatitis E virus nanoparticles (HEVNPs) are virus-like particles that have been investigated as drug delivery agents for the targeted delivery of nucleic acids and small proteins. HEVNPs can be a theranostic platform for monitoring and evaluating tumor-targeted therapies if tagged with a suitable diagnostic marker. Herein, we describe the radiolabeling and biological evaluation of integrin α₃β₁-targeted HEVNPs. HEVNPs were conjugated with DOTA and radiolabeled with gallium-68 (t_1/2 = 67.7 min), a short-lived positron emitter used in positron emission tomography (PET). The synthesized [⁶⁸Ga]Ga-DOTA-HEVNPs were used to evaluate the efficacy of conjugated LXY30 peptide to improve HEVNPs binding and internalization to integrin α₃β₁ expressing human colorectal HCT 116 cells. In vivo tumor accumulation of [⁶⁸Ga]Ga-DOTA-HEVNP-LXY30 was evaluated in HCT 116 colorectal tumor-bearing mice. [⁶⁸Ga]Ga-DOTA-HEVNP-LXY30 and non-targeted [⁶⁸Ga]Ga-DOTA-HEVNP were radiolabeled with radiochemical yields (RCY) of 67.9 ± 3.3% and 73.7 ± 9.8%, respectively. [⁶⁸Ga]Ga-DOTA-HEVNP-LXY30 exhibited significantly higher internalization in HCT 116 cells than the non-targeted [⁶⁸Ga]Ga-DOTA-HEVNPs (21.0 ± 0.7% vs. 10.5 ± 0.3% at 3 h, ****P<0.0001). After intravenous administration to mice, accumulation of [⁶⁸Ga]Ga-DOTA-HEVNP-LXY30 to HCT 116 xenograft tumors was at its highest rate of 0.8 ± 0.4%ID/g at 60 min. [⁶⁸Ga]Ga-DOTA-HEVNP-LXY30 accumulated mainly in the liver and spleen (39.8 ± 13.0%%ID/g and 24.6 ± 24.1%ID/g, respectively). Despite the low targeting efficiency in vivo, we demonstrated that [⁶⁸Ga]Ga-DOTA-HEVNP is a promising diagnostic platform for quantitative analysis of HEVNP distribution in vivo. This nanosystem can be utilized in future studies assessing the success of further engineered HEVNP structures with optimized targeting efficiency in vivo.

Mechanisms of colorectal liver metastasis development

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide, largely due to the development of colorectal liver metastases (CRLM). For the establishment of CRLM, CRC cells must remodel their tumor-microenvironment (TME), avoid the immune system, invade the underlying stroma, survive the hostile environment of the circulation, extravasate into the liver, reprogram the hepatic microenvironment into a permissive pre-metastatic niche, and finally, awake from a dormant state to grow out into clinically detectable CRLM. These steps form part of the invasion-metastasis cascade that relies on reciprocal interactions between the tumor and its ever-changing microenvironment. Such interplay provides a strong rational for therapeutically targeting the TME. In fact, several TME constituents, such as VEGF, TGF-β coreceptor endoglin, and CXCR4, are already targeted in clinical trials. It is, however, of utmost importance to fully understand the complex interactions in the invasion-metastasis cascade to identify novel potential therapeutic targets and prevent the establishment of CRLM, which may ultimately greatly improve patient outcome.

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.

Seeding metastases: The role and clinical utility of circulating tumour cells

Peripheral human blood is a readily-accessible source of patient material in which circulating tumour cells (CTCs) can be found. Their isolation and characterization holds the potential to provide prognostic value for various solid cancers. Enumeration of CTCs from blood is becoming a common practice in informing prognosis and may guide therapy decisions. It is further recognized that enumeration alone does not capture perspective on the heterogeneity of tumours and varying functional abilities of the CTCs to interact with the secondary microenvironment. Characterizing the isolated CTCs further, in particular assessing their functional abilities, can track molecular changes in the disease progress. As a step towards identifying a suite of functional features of CTCs that could aid in clinical decisions, developing a CTC isolation technique based on extracellular matrix (ECM) interactions may provide a more solid foundation for isolating the cells of interest. Techniques based on size, charge, density, and single biomarkers are not sufficient as they underutilize other characteristics of cancer cells. The ability of cancer cells to interact with ECM proteins presents an opportunity to utilize their full character in capturing, and also allows assessment of the features that reveal how cells might behave at secondary sites during metastasis. This article will review some common techniques and recent advances in CTC capture technologies. It will further explore the heterogeneity of the CTC population, challenges they experience in their metastatic journey, and the advantages of utilizing an ECM-based platform for CTC capture. Lastly, we will discuss how tailored ECM approaches may present an optimal platform to capture an influential heterogeneous population of CTCs.

Ruthenium Complexes: An Alternative to Platinum Drugs in Colorectal Cancer Treatment

Colorectal cancer (CRC) is one of the intimidating causes of death around the world. CRC originated from mutations of tumor suppressor genes, proto-oncogenes and DNA repair genes. Though platinum (Pt)-based anticancer drugs have been widely used in the treatment of cancer, their toxicity and CRC cells' resistance to Pt drugs has piqued interest in the search for alternative metal-based drugs. Ruthenium (Ru)-based compounds displayed promising anticancer activity due to their unique chemical properties. Ru-complexes are reported to exert their anticancer activities in CRC cells by regulating different cell signaling pathways that are either directly or indirectly associated with cell growth, division, proliferation, and migration. Additionally, some Ru-based drug candidates showed higher potency compared to commercially available Pt-based anticancer drugs in CRC cell line models. Meanwhile Ru nanoparticles coupled with photosensitizers or anticancer agents have also shown theranostic potential towards CRC. Ru-nanoformulations improve drug efficacy, targeted drug delivery, immune activation, and biocompatibility, and therefore may be capable of overcoming some of the existing chemotherapeutic limitations. Among the potential Ru-based compounds, only Ru (III)-based drug NKP-1339 has undergone phase-Ib clinical trials in CRC treatment.

The response of PIK3CA/KRAS-mutant colorectal cancer stem-like cells to RGD-peptide FraC produced by the strawberry anemone: A promising water-soluble peptide-based inhibitor of metastasis-driver gene CXCR4, stem cell regulatory genes and self-renewal

Colorectal cancer (CRC) is a stem cell-based disease. PIK3CA/KRAS-mutant CRC stem cells (CRCSCs) display high self-renewal, metastatic properties, high activity of PI3K and KRAS signaling pathways with chemoresistant phenotypes. Recently, RGD peptide (containing Arg-Gly-Asp motif)-based therapy of solid tumor cells has attracted much attention. However, little is known whether this method can target self-renewal capacity, key effectors of PI3K and KRAS signaling pathways such as metastasis-driver gene CXCR4 and stem cell regulatory genes with caspase-3 reactivation in CRCSCs overexpressing RGD-dependent integrins. The sea anemone Actinia fragacea produces a water-soluble RGD-peptide fragacea toxin C (FraC) suggesting the possible activity of FraC against PIK3CA/KRAS-mutant CRCSCs. Recombinant FraC was expressed via pET-28a(+)-FraC in E. coli and purified through affinity chromatography followed by performing SDS-PAGE and hemolytic activity assay. Next, PIK3CA/KRAS-mutant HCT-116 cells that serve as an attractive model for CRCSCs were treated with FraC. Thereafter, cell numbers, viability, proliferation, LDH activity, cytotoxicity index, CXCR4 and pluripotency network genes expression, self-renewal capacity, caspase-3 activity with apoptosis were evaluated. Caspase-1, -2, -3,…, -9 sequences were analyzed for RGD-binding motifs. FraC sequence and structure were also evaluated by bioinformatics software. FraC altered cellular morphology to round shapes and disrupted cell connections. 48 h post-treatment with 0.056- to 7.2 μM FraC resulted in 12 %-99 % and 8 %-97.6 % decreases in cell numbers and viabilities respectively and increased LDH activity by 0.2 %-66.7 % in a dose-dependent manner. The results of the cytotoxicity index showed that FraC induces significant toxicity on HCT-116 cells compared to PBMCs and Huvec cells. FraC dramatically decreased the expression of CXCR4 and pluripotency network genes Bmi-1, Sox-2, Oct-4 and Nanog followed by remarkable decreases in self-renewal capacity ranged from 91- to 0 colonies per well for 0.056- to 3.6 μM FraC after 2 weeks. Caspase-3 was found to contain an RGD-binding motif and its activity increased with increasing FraC concentrations followed by apoptosis induction. Potential RGD-binding motifs for FraC were also found in caspase-1, -7, -8 and -9. Unique advantages of FraC peptide, such as low molecular weight, water solubility, high sensitivity of CRC stem-like cells with more selective toxicity to this compound, targeting tumor cell membrane and self-renewal capacity along with the modulation of CXCR4 and stem cell regulatory genes as upstream and downstream effectors of undruggable PI3K and KRAS signaling pathways may open up avenues for FraC peptide-based therapy of PIK3CA/KRAS-mutant CRCSCs with lower toxicity on healthy cells.

HAS3-induced extracellular vesicles from melanoma cells stimulate IHH mediated c-Myc upregulation via the hedgehog signaling pathway in target cells

Intercellular communication is fundamental to the survival and maintenance of all multicellular systems, whereas dysregulation of communication pathways can drive cancer progression. Extracellular vesicles (EVs) are mediators of cell-to-cell communication that regulate a variety of cellular processes involved in tumor progression. Overexpression of a specific plasma membrane enzyme, hyaluronan synthase 3 (HAS3), is one of the factors that can induce EV shedding. HAS3, and particularly its product hyaluronan (HA), are carried by EVs and are known to be associated with the tumorigenic properties of cancer cells. To elucidate the specific effects of cancerous, HAS3-induced EVs on target cells, normal human keratinocytes and melanoma cells were treated with EVs derived from GFP-HAS3 expressing metastatic melanoma cells. We found that the HA receptor CD44 participated in the regulation of EV binding to target cells. Furthermore, GFP-HAS3-positive EVs induced HA secretion, proliferation and invasion of target cells. Our results suggest that HAS3-EVs contains increased quantities of IHH, which activates the target cell hedgehog signaling cascade and leads to the activation of c-Myc and regulation of claspin expression. This signaling of IHH in HAS3-EVs resulted in increased cell proliferation. Claspin immunostaining correlated with HA content in human cutaneous melanocytic lesions, supporting our in vitro findings and suggesting a reciprocal regulation between claspin expression and HA synthesis. This study shows for the first time that EVs originating from HAS3 overexpressing cells carry mitogenic signals that induce proliferation and epithelial-to-mesenchymal transition in target cells. The study also identifies a novel feedback regulation between the hedgehog signaling pathway and HA metabolism in melanoma, mediated by EVs carrying HA and IHH.

Mining TCGA database for genes of prognostic value in gastric cancer microenvironment

Gastric cancer (GC) is the sixth most common malignancy and the third leading cause of cancer‐related death worldwide. Emerging evidence suggests that tumour microenvironment cells play a vital role in the development and prognosis of GC. To investigate the possible effect of stromal scores and immune scores on the overall survival (OS) on the GC patients, we divided GC patients into ‘high’ and ‘low’ groups based on their stromal and immune scores, and found differentially expressed genes related to prognosis of GC patients. Functional enrichment analysis and GSVA further revealed that focal adhesion and ECM‐receptor interaction are associated with GC patients' survival. Finally, we analysed the effects of genes commonly involved in focal adhesion and ECM‐receptor interaction on GC patients' survival and validated our results in another GC cohort from GEO data sets. In conclusion, we obtained a list of tumour microenvironment‐related genes that predict poor prognosis in GC patients.

Identification and clinical validation of metastasis-associated biomarkers based on large-scale samples in colon-adenocarcinoma

AIM

Distant metastasis is the main cause of death in patients with colon-adenocarcinoma(COAD). Due to the lack of effective molecular markers and treatment, the prognosis of patients with metastatic colon cancer is still rather poor.

METHODS

Metastatic related signature (MRS) of stage I and stage IV in colon cancer were identified from different cohorts. Univariate cox regression is used to analyze the relationship between MRS and the overall survival. L1000FWD and DGIdb databases are used to identify molecular drugs. Expression and functional experimental validation of the hub MRS were carried out.

RESULTS

16 MRS were identified, of which 14 MRS was significantly correlated with overall survival. Further functional enrichment analysis showed that MRS was significantly involved with important biological functions such as cell migration, and apoptosis. As important metastatic related genes, GSR, FAS and CYP1B1 have significant interaction with drug molecules. Further studies have confirmed that the expression of FAS and GSR is low, and inhibition of its expression can promote the metastasis of COAD. CYP1B1 expression is highly expressed, and inhibition of its expression can attenuate the malignant biological behavior of colon cancer.

CONCLUSION

Our research could increase the understanding of the mechanism of colon cancer metastasis and provide theoretical basis for the treatment of metastatic colon cancer.

KV11.1 Potassium Channel and the Na+/H+ Antiporter NHE1 Modulate Adhesion-Dependent Intracellular pH in Colorectal Cancer Cells

Increasing evidence indicates that ion channels and transporters cooperate in regulating different aspects of tumor pathophysiology. In cancer cells, H⁺/HCO₃^- transporters usually invert the transmembrane pH gradient typically observed in non-neoplastic cells, which is thought to contribute to cancer malignancy. To what extent the pH-regulating transporters are functionally linked to K⁺ channels, which are central regulators of cell membrane potential (V_m), is unclear. We thus investigated in colorectal cancer cells the implication of the pH-regulating transporters and K_V11.1 (also known as hERG1) in the pH modifications stimulated by integrin-dependent cell adhesion. Colorectal cancer cell lines (HCT 116 and HT 29) were seeded onto β1 integrin-dependent substrates, collagen I and fibronectin. This led to a transient cytoplasmic alkalinization, which peaked at 90 min of incubation, lasted approximately 180 min, and was inhibited by antibodies blocking the β1 integrin. The effect was sensitive to amiloride (10 µM) and cariporide (5 µM), suggesting that it was mainly caused by the activity of the Na⁺/H⁺ antiporter NHE1. Blocking K_V11.1 with E4031 shows that channel activity contributed to modulate the β1 integrin-dependent pH_i increase. Interestingly, both NHE1 and K_V11.1 modulated the colorectal cancer cell motility triggered by β1 integrin-dependent adhesion. Finally, the β1 integrin subunit, K_V11.1 and NHE1 co-immunoprecipitated in colorectal cancer cells seeded onto Collagen I, suggesting the formation of a macromolecular complex following integrin-mediated adhesion. We conclude that the interaction between K_V11.1, NHE1, and β1 integrin contributes to regulate colorectal cancer intracellular pH in relation to the tumor microenvironment, suggesting novel pharmacological targets to counteract pro-invasive and, hence, pro-metastatic behavior in colorectal cancer.

Laminin 521 enhances self-renewal via STAT3 activation and promotes tumor progression in colorectal cancer

Remodeling of basement membrane proteins contributes to tumor progression towards the metastatic stage. One of these proteins, laminin 521 (LN521), sustains embryonic and induced pluripotent stem cell self-renewal, but its putative role in cancer is poorly described. In the present study we found that LN521 promotes colorectal cancer (CRC) cell self-renewal and invasion. siRNA-mediated knockdown of endogenously-produced laminin alpha 5, as well as treatment with neutralizing antibodies against integrin α3β1 and α6β1, were able to reverse the effect of LN521 on self-renewal. Exposure of CRC cells to LN521 enhanced STAT3 phosphorylation, and incubation with STAT3 inhibitors Napabucasin and Stattic was sufficient to block the LN521-driven self-renewal increase. Robust expression of laminin alpha 5 was detected in 7/10 liver metastases tissue sections collected from CRC patients as well as in mouse liver metastasis xenografts, in most cases within areas expressing metastasis cancer stem cell markers such as c-KIT and CD44v6. Finally, retrospective analysis of multiple CRC datasets highlighted the significant association between high LN521 mRNA expression and poor clinical outcome in colorectal cancer patients. Collectively our results indicate that high Laminin 521 expression is a frequent feature of metastatic dissemination in CRC and that it promotes cell invasion and self-renewal, the latter through engagement of integrin isoforms and activation of STAT3 signaling.

Integrin α6β4 in Colorectal Cancer: Expression, Regulation, Functional Alterations and Use as a Biomarker

Integrin α6β4 is one of the main laminin receptors and is primarily expressed by epithelial cells as an active component of hemidesmosomes. In this article, after a brief summary about integrins in the gut epithelium in general, I review the knowledge and clinical potential of this receptor in human colorectal cancer (CRC) cells. Most CRC cells overexpress both α6 and β4 subunits, in situ in primary tumours as well as in established CRC cell lines. The mechanisms that lead to overexpression have not yet been elucidated but clearly involve specific transcription factors such as MYC. From a functional point of view, one key element affecting CRC cell behaviour is the relocalization of α6β4 to the actin cytoskeleton, favouring a more migratory and anoikis-resistant phenotype. Another major element is its expression under various molecular forms that have the distinct ability to interact with ligands (α6β4 ± ctd) or to promote pro- or anti-proliferative properties (α6Aβ4 vs. α6Bβ4). The integrin α6β4 is thus involved in most steps susceptible to participation with CRC progression. The potential clinical significance of this integrin has begun to be investigated and recent studies have shown that ITGA6 and ITGB4 can be useful biomarkers for CRC early detection in a non-invasive assay and as a prognostic factor, respectively.

O-GlcNAcylation of ITGA5 facilitates the occurrence and development of colorectal cancer

BACKGROUND/OBJECTIVE

Integrin α5 (ITGA5) as one member of integrins family, plays an important role in promoting cancer cell metastasis and invasion through inducing the communications among different cells or cells with extracellular matrix (ECM). However, the mechanisms underlying ITGA5 in colorectal cancer (CRC) progression need to be explored, especially for its O-GlcNAcylation. To this end, the current study was performed to explore the effects of O-GlcNAcylation on ITGA5 expression, as well as to probe the effects of ITGA5 O-GlcNAcylation on CRC progression.

METHODS

The expression profiles of ITGA5, OGT and O-GlcNAc in CRC tissues and cells were detected by immunohistochemistry (IHC), RT-PCR and western blotting. CCK-8, flow cytometry and xenotransplantation assays were used to assess cell growth, apoptosis and tumorigenesis. Immunoprecipitation (IP), in vitro O-GlcNAcylation of ITGA5 and enzymatic labelling of O-GlcNAc assays were used to detect the O-GlcNAcylation of ITGA5 protein.

RESULTS

The expression of ITGA5, OGT and O-GlcNAc were all elevated in CRC tissues and cells compared with the normal tissues and cells. Up-regulation of ITGA5 in CRC RKO cells enhanced cell growth and tumorigenesis while decreased cell apoptosis, while down-regulation of ITGA5 in CRC SW620 cells decreased cell growth and tumorigenesis and induced cell apoptosis. Besides, PUGNAc, GlcN or PUGNAc + GlcNAc treatment increased ITGA5 protein expression in RKO and SW620 cells, as well as increased its protein stability via enhancing its O-GlcNAcylation.

CONCLUSION

Collectively, the present study makes clear that ITGA5 overexpression accelerates the progression of CRC, which is closely associated to its enhanced O-GlcNAcylation.

Targeting High Expressed α5β1 Integrin in Liver Metastatic Lesions To Resist Metastasis of Colorectal Cancer by RPM Peptide-Modified Chitosan-Stearic Micelles

Liver metastasis is a leading death cause in colorectal cancer. The pathological differences between orthotopic tumors and metastatic lesions increased the therapeutic difficulty of metastasis. Herein, the α₅β₁ integrin receptor expression on metastatic cells was first measured, the result showed that metastatic cells expressed the α₅β₁ integrin higher than that of the original cells from orthotopic tumors. Afterward, RPM peptide-modified chitosan-stearic (RPM-CSOSA) was designed based on α₅β₁ integrin expression. The cytotoxicity and resistance to migration and the invasion ability of the targeting drug delivery system loading doxorubicin (DOX) and curcumin (CUR) were evaluated in vitro. The metastatic inhibition of the targeting drug delivery system was also investigated in HT29 liver metastatic models. The modified RPM peptide could increase the cellular internalization of CSOSA micelles in metastatic tumor cells and endothelial cells mediated by α₅β₁ integrin. The synergistic effects of RPM-CSOSA/DOX and RPM-CSOSA/CUR could obviously inhibit migratory and invasive abilities of HT29 cells and endothelial cells. Moreover, the RPM-CSOSA/DOX&RPM-CSOSA/CUR could obviously decrease the number of metastatic sites by 86.96%, while CSOSA/DOX&CSOSA/CUR decreased liver metastasis by 66.58% compared with that in the saline group. In conclusion, the RPM peptide-modified drug delivery system may provide insights into targeting the metastatic cells overexpressing the α₅β₁ integrin, and it has the potential to inhibit liver metastasis of colorectal cancer.

Focal adhesion kinase: predictor of tumour response and risk factor for recurrence after neoadjuvant chemoradiation in rectal cancer

Rectal cancer represents about 30% of colorectal cancers, being around 50% locally advanced at presentation. Chemoradiation (CRT) followed by total mesorectal excision is the standard of care for these locally advanced stages. However, it is not free of adverse effects and toxicity and the complete pathologic response rate is between 10% and 30%. This makes it extremely important to define factors that can predict response to this therapy. Focal adhesion kinase (FAK) expression has been correlated with worse prognosis in several tumours and its possible involvement in cancer radio‐ and chemosensitivity has been suggested; however, its role in rectal cancer has not been analysed yet. To analyse the association of FAK expression with tumour response to CRT in locally advanced rectal cancer. This study includes 73 patients with locally advanced rectal cancer receiving standard neoadjuvant CRT followed by total mesorectal excision. Focal adhesion kinase protein levels were immunohistochemically analysed in the pre‐treatment biopsies of these patients and correlated with tumour response to CRT and patients survival. Low FAK expression was significantly correlated with local and distant recurrence (P = 0.013). Low FAK expression was found to be a predictive marker of tumour response to neoadjuvant therapy (P = 0.007) and patients whose tumours did not express FAK showed a strong association with lower disease‐free survival (P = 0.01). Focal adhesion kinase expression predicts neoadjuvant CRT response in rectal cancer patients and it is a clinically relevant risk factor for local and distant recurrence.

Inhibition of adhesion, migration and of α5β1 integrin in the HCT-116 colorectal cancer cells treated with the ruthenium drug NAMI-A

NAMI-A, imidazolium trans-imidazoledimethylsulfoxidetetrachlororuthenate, is a ruthenium-based drug characterised by the selective activity against tumour metastases. Previously we have shown the influence of the hepatic microenvironment to direct the arrest of the metastatic cells of colorectal cancer. Here we used the experimental model of HCT-116 colorectal cancer cells in vitro to explore whether the interference with α5β1 integrin may mechanistically explain the anti-metastatic effect of NAMI-A. NAMI-A inhibits two important steps of the tumour metastatic progression of colorectal cancer, i.e. the adhesion and migration of the tumour cells on the extracellular matrix proteins. The fibronectin receptor α5β1 integrin is likely involved in the anti-adhesive effects of NAMI-A on the HCT-116 colorectal cancer cells during their interaction with the extracellular matrix. Mechanistically, NAMI-A decreases the α5β1 integrin expression, and reduces FAK (Focal Adhesion Kinase) auto-phosphorylation on Tyr397, an important signalling event, involved in α5β1 integrin activation. These effects were validated by siRNA-induced knock down of the α5 integrin subunit and/or by the use of specific blocking mAbs against the active site of the integrin. Our results demonstrate the relevance of α5β1 integrin for colorectal cancer. We also show that the anti-metastatic effect of NAMI-A depends on the modulation of this integrin. Thus, our data on NAMI-A support the new concept that metal-based drugs can inhibit tumour metastases through targeting of integrins and of other proteins which mediate tumour progression-related cell functions such as adhesion and migration.

The effects of macroporosity and stiffness of poly[(methyl vinyl ether)-alt-(maleic acid)] cross-linked egg white simulations of an aged extracellular matrix on the proliferation of ovarian cancer cells

The effects of macroporosity and stiffness of P(MVE-alt-MA) cross-linked EW simulations of an aged ECM on the proliferation of cancer cells.

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.

Alpha2beta1 integrin in cancer development and chemoresistance

Extracellular matrix, via its receptors the integrins, has emerged as a crucial factor in cancer development. The α2β1 integrin is a major collagen receptor that is widely expressed and known to promote cell migration and control tissue homeostasis. Growing evidence suggests that it can be a key pathway in cancer. Recent studies have shown that α2β1 integrin is a regulator of cancer metastasis either by promoting or inhibiting the dissemination process of cancer cells. The α2β1 integrin signaling can also enhance tumor angiogenesis. Emerging evidence supports a role for α2β1 integrin in cancer chemoresistance especially in hematological malignancies originating from the T cell lineage. In addition, α2β1 integrin has been associated with cancer stem cells. In this review, we will discuss the complex role of α2β1 integrin in these processes. Collagen is a major matrix protein of the tumor microenvironment and thus, understanding how α2β1 integrin regulates cancer pathogenesis is likely to lead to new therapeutic approaches and agents for cancer treatment.