RESUMO
BACKGROUND: Ovarian cancer (OC) remains one of the most challenging and deadly malignancies facing women today. While PARP inhibitors (PARPis) have transformed the treatment landscape for women with advanced OC, many patients will relapse and the PARPi-resistant setting is an area of unmet medical need. Traditional immunotherapies targeting PD-1/PD-L1 have failed to show any benefit in OC. The CD47/TSP-1 axis may be relevant in OC. We aimed to describe changes in CD47 expression with platinum therapy and their relationship with immune features and prognosis. METHODS: Tumor and blood samples collected from OC patients in the CHIVA trial were assessed for CD47 and TSP-1 before and after neoadjuvant chemotherapy (NACT) and multiplex analysis was used to investigate immune markers. Considering the therapeutic relevance of targeting the CD47/TSP-1 axis, we used the CD47-derived TAX2 peptide to selectively antagonize it in a preclinical model of aggressive ovarian carcinoma. RESULTS: Significant reductions in CD47 expression were observed post NACT. Tumor patients having the highest CD47 expression profile at baseline showed the greatest CD4+ and CD8+ T-cell influx post NACT and displayed a better prognosis. In addition, TSP-1 plasma levels decreased significantly under NACT, and high TSP-1 was associated with a worse prognosis. We demonstrated that TAX2 exhibited a selective and favorable biodistribution profile in mice, localizing at the tumor sites. Using a relevant peritoneal carcinomatosis model displaying PARPi resistance, we demonstrated that post-olaparib (post-PARPi) administration of TAX2 significantly reduced tumor burden and prolonged survival. Remarkably, TAX2 used sequentially was also able to increase animal survival even under treatment conditions allowing olaparib efficacy. CONCLUSIONS: Our study thus (1) proposes a CD47-based stratification of patients who may be most likely to benefit from postoperative immunotherapy, and (2) suggests that TAX2 is a potential alternative therapy for patients relapsing on PARP inhibitors.
Assuntos
Biomarcadores Tumorais , Antígeno CD47 , Neoplasias Ovarianas , Trombospondina 1 , Antígeno CD47/metabolismo , Feminino , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Biomarcadores Tumorais/metabolismo , Animais , Camundongos , Trombospondina 1/metabolismo , Prognóstico , Linhagem Celular Tumoral , Terapia Neoadjuvante , Ensaios Antitumorais Modelo de Xenoenxerto , Pessoa de Meia-Idade , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacosRESUMO
The low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional endocytic receptor mediating the clearance of various molecules from the extracellular matrix. LRP1 also regulates cell surface expression of matrix receptors by modulating both extracellular and intracellular signals, though current knowledge of the underlying mechanisms remains partial in the frame of cancer cells interaction with matricellular substrates. In this study we identified that LRP1 downregulates calpain activity and calpain 2 transcriptional expression in an invasive thyroid carcinoma cell model. LRP1-dependent alleviation of calpain activity limits cell-matrix attachment strength and contributes to FTC133 cells invasive abilities in a modified Boyden chamber assays. In addition, using enzymatic assays and co-immunoprecipitation experiments, we demonstrated that LRP1 exerts post-translational inhibition of calpain activity through PKA-dependent phosphorylation of calpain-2. This LRP-1 dual mode of control of calpain activity fine-tunes carcinoma cell spreading. We showed that LRP1-mediated calpain inhibition participates in talin-positive focal adhesions dissolution and limits ß1-integrin expression at carcinoma cell surface. In conclusion, we identified an additional and innovative intracellular mechanism which demonstrates LRP-1 pro-motile action in thyroid cancer cells. LRP-1 ability to specifically control calpain-2 expression and activity highlights a novel facet of its de-adhesion receptor status.
RESUMO
The low-density lipoprotein receptor (LDLR) family comprises 14 single-transmembrane receptors sharing structural homology and common repeats. These receptors specifically recognize and internalize various extracellular ligands either alone or complexed with membrane-spanning co-receptors that are then sorted for lysosomal degradation or cell-surface recovery. As multifunctional endocytic receptors, some LDLR members from the core family were first considered as potential tumor suppressors due to their clearance activity against extracellular matrix-degrading enzymes. LDLRs are also involved in pleiotropic functions including growth factor signaling, matricellular proteins, and cell matrix adhesion turnover and chemoattraction, thereby affecting both tumor cells and their surrounding microenvironment. Therefore, their roles could appear controversial and dependent on the malignancy state. In this review, recent advances highlighting the contribution of LDLR members to breast cancer progression are discussed with focus on (1) specific expression patterns of these receptors in primary cancers or distant metastasis and (2) emerging mechanisms and signaling pathways. In addition, potential diagnosis and therapeutic options are proposed.
RESUMO
Colorectal cancer is the second most common cancer diagnosed in men and the third most commonly occurring in women worldwide. Interactions between cells and the surrounding extracellular matrix (ECM) are involved in tumor development and progression of many types of cancer. The organization of the ECM molecules provides not only physical scaffoldings and dynamic network into which cells are embedded but also allows the control of many cellular behaviors including proliferation, migration, differentiation, and survival leading to homeostasis and morphogenesis regulation. Modifications of ECM composition and mechanical properties during carcinogenesis are critical for tumor initiation and progression. The core matrisome consists of five classes of macromolecules, which are collagens, laminins, fibronectin, proteoglycans, and hyaluronans. In most tissues, fibrillar collagen is the major component of ECM. Cells embedded into fibrillar collagen interact with it through their surface receptors, such as integrins and discoidin domain receptors (DDRs). On the one hand, cells incorporate signals from ECM that modify their functionalities and behaviors. On the other hand, all cells within tumor environment (cancer cells, cancer-associated fibroblasts, endothelial cells, and immune cells) synthesize and secrete matrix macromolecules under the control of multiple extracellular signals. This cell-ECM dialog participates in a dynamic way in ECM formation and its biophysical and biochemical properties. Here, we will review the functional interplay between cells and collagen network within the tumor microenvironment during colorectal cancer progression.
RESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
RESUMO
Resistance to antiangiogenic drugs limits their applicability in cancer therapy. Here, we show that revascularization and progression of pancreatic neuroendocrine tumors (PNETs) under extended vascular-endothelial growth factor A (VEGFA) blockade are dependent on periostin (POSTN), a matricellular protein expressed by stromal cells. Genetic deletion of Postn in RIP1-Tag2 mice blunted tumor rebounds of M2-like macrophages and αSMA+ stromal cells in response to prolonged VEGFA inhibition and suppressed PNET revascularization and progression on therapy. POSTN deficiency also impeded the upregulation of basic fibroblast growth factor (FGF2), an adaptive mechanism previously implicated in PNET evasion from antiangiogenic therapy. Higher POSTN expression correlated with markers of M2-like macrophages in human PNETs, and depleting macrophages with a colony-stimulating factor 1 receptor (CSF1R) antibody inhibited PNET revascularization and progression under VEGFA blockade despite continued POSTN production. These findings suggest a role for POSTN in orchestrating resistance to anti-VEGFA therapy in PNETs.
Assuntos
Moléculas de Adesão Celular/metabolismo , Tumores Neuroendócrinos/metabolismo , Neoplasias Pancreáticas/metabolismo , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Inibidores da Angiogênese/farmacologia , Inibidores da Angiogênese/uso terapêutico , Animais , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Macrófagos/metabolismo , Camundongos Transgênicos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/metabolismo , Tumores Neuroendócrinos/irrigação sanguínea , Tumores Neuroendócrinos/tratamento farmacológico , Tumores Neuroendócrinos/genética , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos , Células Estromais/efeitos dos fármacos , Células Estromais/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
LRP-1 is a large endocytic receptor mediating the clearance of various molecules from the extracellular matrix. LRP-1 was reported to control focal adhesion turnover to optimize the adhesion-deadhesion balance to support invasion. To better understand how LRP-1 coordinates cell-extracellular matrix interface, we explored its ability to regulate cell surface integrins in thyroid carcinomas. Using an antibody approach, we demonstrated that ß1-integrin levels were increased at the plasma membrane under LRP1 silencing or upon RAP treatment, used as LRP-1 antagonist. Our data revealed that LRP-1 binds with both inactive and active ß1-integrin conformations and identified the extracellular ligand-binding domains II or IV of LRP-1 as sufficient to bind ß1-integrin. Using a recombinant ß1-integrin, we demonstrated that LRP-1 acts as a regulator of ß1-integrin intracellular traffic. Moreover, RAP or LRP-1 blocking antibodies decreased up to 36% the number of ß1-integrin-containing endosomes. LRP-1 blockade did not significantly affect the levels of ß1-integrin-containing lysosomes while decreasing localization of ß1-integrin within Rab-11 positive vesicles. Overall, we identified an original molecular process in which LRP-1 acts as a main regulator of ß1-integrin internalization and recycling in thyroid cancer cells.
RESUMO
Intermediate filaments are involved in stress-related cell mechanical properties and in plasticity via the regulation of focal adhesions (FAs) and the actomyosin network. We investigated whether vimentin regulates endothelial cells (ECs) and vascular smooth muscle cells (SMCs) and thereby influences vasomotor tone and arterial stiffness. Vimentin knockout mice (Vim-/-) exhibited increased expression of laminin, fibronectin, perlecan, collagen IV and VE-cadherin as well as von Willebrand factor deposition in the subendothelial basement membrane. Smooth muscle (SM) myosin heavy chain, α-SM actin and smoothelin were decreased in Vim-/- mice. Electron microscopy revealed a denser endothelial basement membrane and increased SM cell-matrix interactions. Integrin αv, talin and vinculin present in FAs were increased in Vim-/- mice. Phosphorylated FA kinase and its targets Src and ERK1/2 were elevated in Vim-/- mice. Knockout of vimentin, but not of synemin, resulted in increased carotid stiffness and contractility and endothelial dysfunction, independently of blood pressure and the collagen/elastin ratio. The increase in arterial stiffness in Vim-/- mice likely involves vasomotor tone and endothelial basement membrane organization changes. At the tissue level, the results show the implication of FAs both in ECs and vascular SMCs in the role of vimentin in arterial stiffening.
Assuntos
Membrana Basal/metabolismo , Doenças das Artérias Carótidas/etiologia , Doenças das Artérias Carótidas/metabolismo , Regulação da Expressão Gênica , Filamentos Intermediários/genética , Filamentos Intermediários/metabolismo , Rigidez Vascular/genética , Vimentina/deficiência , Animais , Biomarcadores , Pressão Sanguínea , Doenças das Artérias Carótidas/fisiopatologia , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Modelos Animais de Doenças , Endotélio/metabolismo , Imunofluorescência , Fenômenos Mecânicos , Camundongos , Camundongos Knockout , Microscopia Confocal , Vasodilatação/genéticaRESUMO
High expression of the extracellular matrix component tenascin-C in the tumor microenvironment correlates with decreased patient survival. Tenascin-C promotes cancer progression and a disrupted tumor vasculature through an unclear mechanism. Here, we examine the angiomodulatory role of tenascin-C. We find that direct contact of endothelial cells with tenascin-C disrupts actin polymerization, resulting in cytoplasmic retention of the transcriptional coactivator YAP. Tenascin-C also downregulates YAP pro-angiogenic target genes, thus reducing endothelial cell survival, proliferation, and tubulogenesis. Glioblastoma cells exposed to tenascin-C secrete pro-angiogenic factors that promote endothelial cell survival and tubulogenesis. Proteomic analysis of their secretome reveals a signature, including ephrin-B2, that predicts decreased survival of glioma patients. We find that ephrin-B2 is an important pro-angiogenic tenascin-C effector. Thus, we demonstrate dual activities for tenascin-C in glioblastoma angiogenesis and uncover potential targeting and prediction opportunities.
Assuntos
Efrina-B2/genética , Glioblastoma/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Proteínas Nucleares/genética , Tenascina/administração & dosagem , Fatores de Transcrição/genética , Animais , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Camundongos , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Proteômica , Transdução de Sinais , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Angiogenesis represents a rate-limiting step during tumor progression. Targeting angiogenesis is already applied in cancer treatment, yet limits of anti-angiogenic therapies have emerged, notably because tumors adapt and recur after treatment. Therefore, there is a strong need to better understand the molecular and cellular mechanisms underlying tumor angiogenesis. Using the RIP1-Tag2 transgenic murine model, we identified 298 genes that are deregulated during the angiogenic switch, revealing an ingression/expansion of specific stromal cell types including endothelial cells and pericytes, but also macrophages and perivascular mesenchymal cells. Canonical TGF-ß signaling is up-regulated during the angiogenic switch, especially in tumor-associated macrophages and fibroblasts. The matrisome, comprising extracellular matrix (ECM) and ECM-associated molecules, is significantly enriched, which allowed us to define the AngioMatrix signature as the 110 matrisomal genes induced during the RIP1-Tag2 angiogenic switch. Several AngioMatrix molecules were validated at expression level. Ablation of tenascin-C, one of the most highly induced ECM molecules during the switch, resulted in reduced angiogenesis confirming its important role. In human glioma and colorectal samples, the AngioMatrix signature correlates with the expression of endothelial cell markers, is increased with tumor progression and finally correlates with poor prognosis demonstrating its diagnostic and therapeutic potential.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias Colorretais/genética , Matriz Extracelular/metabolismo , Proteínas Ativadoras de GTPase/fisiologia , Perfilação da Expressão Gênica , Glioma/genética , Neovascularização Patológica/genética , Animais , Biomarcadores Tumorais/metabolismo , Células Cultivadas , Neoplasias Colorretais/irrigação sanguínea , Neoplasias Colorretais/mortalidade , Fibroblastos/citologia , Fibroblastos/metabolismo , Glioma/irrigação sanguínea , Glioma/mortalidade , Humanos , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Transgênicos , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Células Estromais/citologia , Células Estromais/metabolismo , Taxa de SobrevidaRESUMO
The extracellular matrix molecule tenascin-C (TNC) is a major component of the cancer-specific matrix, and high TNC expression is linked to poor prognosis in several cancers. To provide a comprehensive understanding of TNC's functions in cancer, we established an immune-competent transgenic mouse model of pancreatic ß-cell carcinogenesis with varying levels of TNC expression and compared stochastic neuroendocrine tumor formation in abundance or absence of TNC. We show that TNC promotes tumor cell survival, the angiogenic switch, more and leaky vessels, carcinoma progression, and lung micrometastasis. TNC downregulates Dickkopf-1 (DKK1) promoter activity through the blocking of actin stress fiber formation, activates Wnt signaling, and induces Wnt target genes in tumor and endothelial cells. Our results implicate DKK1 downregulation as an important mechanism underlying TNC-enhanced tumor progression through the provision of a proangiogenic tumor microenvironment.
Assuntos
Regulação para Baixo , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Tenascina/metabolismo , Proteínas Wnt/metabolismo , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Modelos Animais de Doenças , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neovascularização Patológica , Tumores Neuroendócrinos/metabolismo , Tumores Neuroendócrinos/patologia , Transdução de Sinais , Tenascina/deficiência , Tenascina/genética , Proteínas Wnt/antagonistas & inibidoresRESUMO
The low-density lipoprotein receptor-related protein 1 (LRP-1) is a large endocytic receptor mediating the clearance of various molecules from the extracellular matrix. In the field of cancer, LRP-1-mediated endocytosis was first associated with antitumor properties. However, recent results suggested that LRP-1 may coordinate the adhesion-deadhesion balance in malignant cells to support tumor progression. Here, we observed that LRP-1 silencing or RAP (receptor-associated protein) treatment led to accumulation of CD44 at the tumor cell surface. Moreover, we evidenced a tight interaction between CD44 and LRP-1, not exclusively localized in lipid rafts. Overexpression of LRP-1-derived minireceptors indicated that the fourth ligand-binding cluster of LRP-1 is required to bind CD44. Labeling of CD44 with EEA1 and LAMP-1 showed that internalized CD44 is routed through early endosomes toward lysosomes in a LRP-1-dependent pathway. LRP-1-mediated internalization of CD44 was highly reduced under hyperosmotic conditions but poorly affected by membrane cholesterol depletion, revealing that it proceeds mostly via clathrin-coated pits. Finally, we demonstrated that CD44 silencing abolishes RAP-induced tumor cell attachment, revealing that cell surface accumulation of CD44 under LRP-1 blockade is mainly responsible for the stimulation of tumor cell adhesion. Altogether, our data shed light on the LRP-1-mediated internalization of CD44 that appeared critical to define the adhesive properties of tumor cells.
Assuntos
Regulação Neoplásica da Expressão Gênica , Receptores de Hialuronatos/biossíntese , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Biotinilação , Adesão Celular , Linhagem Celular Tumoral , Colesterol/metabolismo , Densitometria/métodos , Progressão da Doença , Endocitose , Endossomos/metabolismo , Inativação Gênica , Humanos , Ligantes , Lisossomos/metabolismo , Microdomínios da Membrana , Neoplasias/metabolismo , Neoplasias/patologia , Plasmídeos/metabolismo , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/patologiaRESUMO
Tenascin-C is an extracellular matrix glycoprotein that is specifically and transiently expressed upon tissue injury. Upon tissue damage, tenascin-C plays a multitude of different roles that mediate both inflammatory and fibrotic processes to enable effective tissue repair. In the last decade, emerging evidence has demonstrated a vital role for tenascin-C in cardiac and arterial injury, tumor angiogenesis and metastasis, as well as in modulating stem cell behavior. Here we highlight the molecular mechanisms by which tenascin-C mediates these effects and discuss the implications of mis-regulated tenascin-C expression in driving disease pathology.
Assuntos
Tenascina/fisiologia , Animais , Aterosclerose/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Regulação da Expressão Gênica , Humanos , Camundongos , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Miócitos de Músculo Liso/fisiologia , Neoplasias/diagnóstico , Neoplasias/metabolismo , Neoplasias/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Ratos , Células-Tronco/metabolismo , Células-Tronco/patologia , Tenascina/sangue , Tenascina/química , Doenças Vasculares/metabolismo , Doenças Vasculares/patologia , Cicatrização/fisiologiaRESUMO
BACKGROUND: The low-density lipoprotein receptor-related protein-1 (LRP-1) is an endocytic receptor mediating the clearance of various extracellular molecules involved in the dissemination of cancer cells. LRP-1 thus appeared as an attractive receptor for targeting the invasive behavior of malignant cells. However, recent results suggest that LRP-1 may facilitate the development and growth of cancer metastases in vivo, but the precise contribution of the receptor during cancer progression remains to be elucidated. The lack of mechanistic insights into the intracellular signaling networks downstream of LRP-1 has prevented the understanding of its contribution towards cancer. METHODOLOGY/PRINCIPAL FINDINGS: Through a short-hairpin RNA-mediated silencing approach, we identified LRP-1 as a main regulator of ERK and JNK signaling in a tumor cell context. Co-immunoprecipitation experiments revealed that LRP-1 constitutes an intracellular docking site for MAPK containing complexes. By using pharmacological agents, constitutively active and dominant-negative kinases, we demonstrated that LRP-1 maintains malignant cells in an adhesive state that is favorable for invasion by activating ERK and inhibiting JNK. We further demonstrated that the LRP-1-dependent regulation of MAPK signaling organizes the cytoskeletal architecture and mediates adhesive complex turnover in cancer cells. Moreover, we found that LRP-1 is tethered to the actin network and to focal adhesion sites and controls ERK and JNK targeting to talin-rich structures. CONCLUSIONS: We identified ERK and JNK as the main molecular relays by which LRP-1 regulates focal adhesion disassembly of malignant cells to support invasion.
Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Transdução de Sinais/fisiologia , Western Blotting , Adesão Celular/genética , Adesão Celular/fisiologia , Linhagem Celular Tumoral , MAP Quinases Reguladas por Sinal Extracelular/genética , Humanos , Imunoprecipitação , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Microscopia de Fluorescência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genéticaRESUMO
Doxorubicin and camptothecin are two cytotoxic chemotherapeutic agents triggering apoptosis in various cancer cells, including thyroid carcinoma cells. Recent studies revealed a critical role of ceramide in chemotherapy and suggested that anti-cancer drugs may kill tumor cells through sphingomyelinase activation. However, in comparison to sphingomyelin hydrolysis, the relative involvement of de novo ceramide synthesis remained poorly explored and highly controversial. Here, we evidenced that both doxorubicin and camptothecin triggered ceramide accumulation in thyroid carcinoma cells. We demonstrated that ceramide increase occurred via the de novo pathway without neither acidic nor neutral sphingomyelinase contribution. Interestingly, de novo ceramide generation was responsible for the drug-induced malignant cell apoptosis through a caspase-3-dependent pathway and a decrease of thrombospondin amount. Furthermore, blocking ceramide metabolism by inhibiting glucosylceramide synthase strengthened the camptothecin and doxorubicin-dependent effects. Altogether, we evidenced that de novo ceramide synthesis mediates the anti-tumor properties of doxorubicin and camptothecin in thyroid carcinoma and suggested that glucosylation of ceramide may contribute to the drug-resistance phenotype in thyroid malignancies.
Assuntos
Adenocarcinoma Folicular/tratamento farmacológico , Camptotecina/farmacologia , Ceramidas/biossíntese , Doxorrubicina/farmacologia , Neoplasias da Glândula Tireoide/tratamento farmacológico , Adenocarcinoma Folicular/metabolismo , Adenocarcinoma Folicular/patologia , Antibióticos Antineoplásicos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Oxirredutases/metabolismo , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/patologia , Células Tumorais CultivadasRESUMO
The scavenger receptor low-density lipoprotein receptor-related protein 1 (LRP-1) mediates the clearance of a variety of biological molecules from the pericellular environment, including proteinases which degrade the extracellular matrix in cancer progression. However, its accurate functions remain poorly explored and highly controversial. Here we show that LRP-1 silencing by RNA interference results in a drastic inhibition of cell invasion despite a strong stimulation of pericellular matrix metalloproteinase 2 and urokinase-type plasminogen activator proteolytic activities. Cell migration in both two and three dimensions is decreased by LRP-1 silencing. LRP-1-silenced carcinoma cells, which are characterized by major cytoskeleton rearrangements, display atypical overspread morphology with a lack of membrane extensions. LRP-1 silencing accelerates cell attachment, inhibits cell-substrate deadhesion, and induces the accumulation, at the cell periphery, of abundant talin-containing focal adhesion complexes deprived of FAK and paxillin. We conclude that in addition to its role in ligand binding and endocytosis, LRP-1 regulates cytoskeletal organization and adhesive complex turnover in malignant cells by modulating the focal complex composition, thereby promoting invasion.
Assuntos
Metaloproteinase 2 da Matriz/metabolismo , Invasividade Neoplásica , Receptores de LDL/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Forma Celular , Endocitose , Quinase 1 de Adesão Focal/metabolismo , Humanos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Paxilina/metabolismo , Interferência de RNA , Receptores de LDL/genética , Talina/fisiologia , Proteínas Supressoras de Tumor/genética , Ativador de Plasminogênio Tipo Uroquinase/metabolismoRESUMO
Previous studies reported that modification in the expression of the matricellular multidomain glycoprotein thrombospondin-1 (TSP-1) could play a critical role in the control of tumor progression and metastasis development. The function of this multimodular protein in cancers appears highly dependent on the cellular context and thus remains to date very difficult to accurately characterize. Controversial results indeed exist reporting either pro- or anti-invasive properties of TSP-1. Since it appeared that TSP-1 could be of prognostic value for certain specific types of cancers, we examined in this study the prospective function of TSP-1 in the control of human follicular thyroid carcinoma (FTC) cell invasiveness. First, we established that the aggressive behavior of human thyroid malignant cells is closely correlated to the TSP-1 amount. We demonstrated that exogenously added TSP-1 stimulates by two-fold the capacity of FTC cells to invade Matrigel-coated wells. The use of specific anti-TSP-1 blocking antibodies led to a drastic inhibition of the basal FTC cell invasion. Zymography experiments revealed that the uPA-dependent proteolytic activity is directly controlled by TSP-1, MMPs activity is not. The TSP-1-mediated stimulation of uPA appears to occur at post-transcriptional level. Finally, we established that the TSP-1-stimulated FTC cell invasion is wholly abolished under anti-uPA blocking antibodies or aprotinin treatments whereas MMP inhibitors have no effect. All together, we evidenced in the present study that TSP-1 promotes human follicular thyroid carcinoma cell invasion mainly through up-regulation of the urokinase-dependent activity.
Assuntos
Trombospondina 1/metabolismo , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/patologia , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Animais , Linhagem Celular Tumoral , Ativação Enzimática , Matriz Extracelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Metaloproteinase 2 da Matriz/metabolismo , Camundongos , Invasividade Neoplásica , Metástase Neoplásica , Prognóstico , Taxa de Sobrevida , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/genéticaRESUMO
The low-density lipoprotein receptor-related protein-1 (LRP-1)is a large scavenger receptor mediating the internalization and catabolism of various biological components from the extracellular matrix. In the past decade, LRP-1 appeared as an attractive receptor for targeting the invasive behavior of cancer cells since this protein is able to reduce the accumulation of extracellular proteinases by endocytosis. However, recent data suggest that LRP-1 could support carcinoma cell invasion depending on the cellular environment. Indeed, in addition to its well-determined role in ligand binding and endocytosis, LRP-1 emerges as a central molecular regulator of cytoskeleton organization and adhesive complex turnover in malignant cells. This commentary reviews the functions played by LRP-1 in cancer-related events and discusses the potential mechanisms whereby LRP-1 is able to control the cellular phenotype of cancer cells.