[Teleconsultation in a coloproctology unit during the COVID-19 pandemic. Preliminary results]. / Teleconsulta en una unidad de coloproctología durante la pandemia de COVID-19. Resultados preliminares.

Introduction: During the state of alarm established in Spain due to the COVID-19 pandemic, most of the face-to-face outpatient consultations were cancelled and a telephone consultation was established to follow up coloproctological patients. The objective of this study was to analyse the efficacy of telemedicine (by telephone) in monitoring patients in a coloproctology unit, in the context of the COVID-19 pandemic. Method: Prospective descriptive study of consecutive patients in a single centre. The result of the teleconsultation was classified as discharge, resolved visit or reprogramming and was analysed by different diagnostic groups. Results: From March 19th to April 17th, 2020, the teleconsultation of 190 patients was carried out. The response rate was 94.2% (179). The diagnostic categories of the patients attended were: 51 (26.9%) colorectal neoplasia, 48 (25.3%) proctological pathology, 72 (37.9%) pelvic floor dysfunctions and 19 (10%) other benign pathologies. 105 (55.26%) could be recited as if they had come in person. Eleven (5.8%) patients were discharged. No significant differences were found between the different diagnostic categories and the resolution of the teleconsultation. The reasons for reprogramming are analyzed in the study. Conclusion: In the context of a pandemic, teleconsultation has allowed 61% of follow-up visits to be definitively solved, avoiding the reprogramming of 116 patients. The new social and health paradigm after the pandemic will require a rethinking of our healthcare model, and in many aspects, telemedicine can offer tools for this.

EphA2 receptor is a key player in the metastatic onset of Ewing sarcoma.

Ewing sarcoma (ES) is the second most common bone malignancy affecting children and young adults with poor prognosis due to high metastasis incidence. Our group previously described that EphA2, a tyrosine kinase receptor, promotes angiogenesis in Ewing sarcoma (ES) cells via ligand-dependent signaling. Now we wanted to explore EphA2 ligand-independent activity, controlled upon phosphorylation at S897 (p-EphA2S897 ), as it has been linked to metastasis in several malignancies. By reverse genetic engineering we explored the phenotypic changes after EphA2 removal or reintroduction. Gene expression microarray was used to identify key players in EphA2 signaling. Mice were employed to reproduce metastatic processes from orthotopically implanted engineered cells. We established a correlation between ES cells aggressiveness and p-EphA2S897 . Moreover, stable overexpression of EphA2 in low EphA2 expression ES cells enhanced proliferation and migration, but not a non-phosphorylable mutant (S987A). Consistently, silencing of EphA2 reduced tumorigenicity, migration and invasion in vitro, and lung metastasis incidence in experimental and spontaneous metastasis assays in vivo. A gene expression microarray revealed the implication of EphA2 in cell signaling, cellular movement and survival. ADAM19 knockdown by siRNA technology strongly reproduced the negative effects on cell migration observed after EphA2 silencing. Altogether, our results suggest that p-EphA2S897 correlates with aggressiveness in ES, so blocking its function may be a promising treatment.

High-resolution circuit for the diagnosis of faecal incontinence. Patient satisfaction. / Circuito de alta resolución en el diagnóstico de la incontinencia fecal. Satisfacción de los pacientes.

INTRODUCTION: Despite its high prevalence, faecal incontinence (FI) is still underrated and underdiagnosed. Moreover, diagnosis and subsequent treatment can be a challenge for the colorectal surgeon because of its associated social taboo and embarrassment, and the wide range of symptoms. The aim of the present study is to describe a new high-resolution circuit (HRC) for FI diagnosis, that was implemented at our center and to evaluate patient satisfaction. METHODS: The structure and organization of the HRC are described. Demographic and clinical data of the patients included in the HRC between February 2014 and June 2016 were collected. Moreover, patients' satisfaction was measured through a structured survey. RESULTS: A total of 321 patients were evaluated in our pelvic floor outpatients clinic during the study period: 65% (210) of them had FI (81% women, median age 66 years). The mean time since FI onset was 24 (range 4-540) months. A total of 79% (165) of the patients were included in the HRC. 62% of them responded to the survey. Of these, only 32% (33) had consulted for FI before coming to our centre. The majority, 88% (90) considered that performing the 2diagnostic tests the same day of the visit was a very good option. And 94% (96) were satisfied with the information received on their FI, with a median satisfaction value of 10 (5-10). CONCLUSION: With the HRC, the patient spends about 2h in the outpatient clinic of the hospital, but leaves with the complete diagnostic process performed. The satisfaction survey confirms that most patients prefer this system.

Targeted therapies in sarcomas: challenging the challenge.

Sarcomas are a heterogeneous group of mesenchymal malignancies that very often lead to death. Nowadays, chemotherapy is the only available treatment for most sarcomas but there are few active drugs and clinical results still remain very poor. Thus, there is an imperious need to find new therapeutic alternatives in order to improve sarcoma patient's outcome. During the last years, there have been described a number of new molecular pathways that have allowed us to know more about cancer biology and tumorigenesis. Sarcomas are one of the tumors in which more advances have been made. Identification of specific chromosomal translocations, some important pathways characterization such as mTOR pathway or the insulin-like growth factor pathway, the stunning development in angiogenesis knowledge, and brand new agents like viruses have lead to the development of new therapeutic options with promising results. This paper makes an exhaustive review of preclinical and clinical evidence of the most recent targeted therapies in sarcomas and provides a future view of treatments that may lead to improve prognosis of patients affected with this disease.

Teleconsultation in a coloproctology unit during the COVID-19 pandemic. Preliminary results. / Teleconsulta en una unidad de coloproctología durante la pandemia de COVID-19. Resultados preliminares.

INTRODUCTION: During the state of alarm established in Spain due to the COVID-19 pandemic, most of the face-to-face outpatient consultations were cancelled and a telephone consultation was established to follow up coloproctological patients. The objective of this study was to analyse the efficacy of telemedicine (by telephone) in monitoring patients in a coloproctology unit, in the context of the COVID-19 pandemic. METHOD: Prospective descriptive study of consecutive patients in a single centre. The result of the teleconsultation was classified as discharge, resolved visit or reprogramming and was analysed by different diagnostic groups. RESULTS: From March 19th to April 17th, 2020, the teleconsultation of 190 patients was carried out. The response rate was 94.2% (179). The diagnostic categories of the patients attended were: 51 (26.9%) colorectal neoplasia, 48 (25.3%) proctological pathology, 72 (37.9%) pelvic floor dysfunctions and 19 (10%) other benign pathologies. 105 (55.26%) could be recited as if they had come in person. Eleven (5.8%) patients were discharged. No significant differences were found between the different diagnostic categories and the resolution of the teleconsultation. The reasons for reprogramming are analyzed in the study. CONCLUSION: In the context of a pandemic, teleconsultation has allowed 61% of follow-up visits to be definitively solved, avoiding the reprogramming of 116 patients. The new social and health paradigm after the pandemic will require a rethinking of our healthcare model, and in many aspects, telemedicine can offer tools for this.

DNA methylation profiling identifies PTRF/Cavin-1 as a novel tumor suppressor in Ewing sarcoma when co-expressed with caveolin-1.

Epigenetic modifications have been shown to be important in developmental tumors as Ewing sarcoma. We profiled the DNA methylation status of 15 primary tumors, 7 cell lines, 10 healthy tissues and 4 human mesenchymal stem cells lines samples using the Infinium Human Methylation 450K. Differential methylation analysis between Ewing sarcoma and reference samples revealed 1166 hypermethylated and 864 hypomethylated CpG sites (Bonferroni p < 0.05, δ-ß-value with absolute difference of >0.20) corresponding to 392 and 470 genes respectively. Gene Ontology analysis of genes differentially methylated in Ewing sarcoma samples showed a significant enrichment of developmental genes. Membrane and cell signal genes were also enriched, among those, 11 were related to caveola formation. We identified differential hypermethylation of CpGs located in the body and S-Shore of the PTRF gene in Ewing sarcoma that correlated with its repressed transcriptional state. Reintroduction of PTRF/Cavin-1 in Ewing sarcoma cells revealed a role of this protein as a tumor suppressor. Restoration of caveolae in the membrane of Ewing sarcoma cells, by exogenously reintroducing PTRF, disrupts the MDM2/p53 complex, which consequently results in the activation of p53 and the induction of apoptosis.

Teleconsulta en una unidad de coloproctología durante la pandemia de COVID-19. Resultados preliminaries / Teleconsultation in a coloproctology unit during the COVID-19 pandemic. Preliminary results

INTRODUCCIÓN: Durante el estado de alarma sanitaria establecido a causa de la pandemia de la COVID-19 se anularon la mayor parte de las consultas externas presenciales y se estableció una consulta telefónica para el seguimiento de pacientes coloproctológicos. El objetivo de este estudio fue analizar la eficacia de la consulta telefónica (teleconsulta) en el seguimiento de los pacientes de una unidad de coloproctología, en el contexto de la pandemia de COVID-19. MÉTODO: Estudio descriptivo prospectivo de pacientes consecutivos en un solo centro. Se clasificó el resultado de la teleconsulta como alta, visita resuelta o reprogramación y se analizó por diferentes grupos diagnósticos. RESULTADOS: Del 19 de marzo al 17 de abril de 2020 se realizó la teleconsulta de 190 pacientes. La tasa de respuesta fue del 94,2% (179). Las categorías diagnósticas de los pacientes atendidos fueron: 51 (26,9%) neoplasia colorrectal, 48 (25,3%) enfermedad proctológica, 72 (37,9%) disfunciones del suelo pélvico y 19 (10%) otras enfermedades benignas. Se pudo volver a citar a 105 (55,26%) como si hubieran venido de forma presencial. Se dio el alta a 11 (5,8%) pacientes. No se encontraron diferencias significativas entre las distintas categorías diagnósticas y la resolución de la teleconsulta. Los motivos de reprogramación se analizan en el estudio. CONCLUSIÓN: En el contexto de pandemia, la teleconsulta ha permitido resolver de forma definitiva el 61% de las visitas de seguimiento y ha evitado la reprogramación de 116 pacientes. El nuevo paradigma social y sanitario tras la pandemia requerirá un replanteamiento de nuestro modelo de atención sanitaria y, en muchos aspectos, la telemedicina puede ofrecer herramientas para ello

INTRODUCTION: During the state of alarm established in Spain due to the COVID-19 pandemic, most of the face-to-face outpatient consultations were cancelled and a telephone consultation was established to follow up coloproctological patients. The objective of this study was to analyse the efficacy of telemedicine (by telephone) in monitoring patients in a coloproctology unit, in the context of the COVID-19 pandemic. METHOD: Prospective descriptive study of consecutive patients in a single centre. The result of the teleconsultation was classified as discharge, resolved visit or reprogramming and was analysed by different diagnostic groups. RESULTS: From March 19th to April 17th, 2020, the teleconsultation of 190 patients was carried out. The response rate was 94.2% (179). The diagnostic categories of the patients attended were: 51 (26.9%) colorectal neoplasia, 48 (25.3%) proctological pathology, 72 (37.9%) pelvic floor dysfunctions and 19 (10%) other benign pathologies. 105 (55.26%) could be recited as if they had come in person. Eleven (5.8%) patients were discharged. No significant differences were found between the different diagnostic categories and the resolution of the teleconsultation. The reasons for reprogramming are analyzed in the study. CONCLUSION: In the context of a pandemic, teleconsultation has allowed 61% of follow-up visits to be definitively solved, avoiding the reprogramming of 116 patients. The new social and health paradigm after the pandemic will require a rethinking of our healthcare model, and in many aspects, telemedicine can offer tools for this

Caveolin-1 promotes Ewing sarcoma metastasis regulating MMP-9 expression through MAPK/ERK pathway.

Ewing sarcoma (ES) is a bone and soft tissue sarcoma affecting mostly children and young adults. Caveolin-1 (CAV1) is a well-known target of EWS/FLI1, the main driver of ES, with an oncogenic role in ES. We have previously described how CAV1 is able to induce metastasis in ES via matrix metalloproteinase-9 (MMP-9). In the present study we showed how CAV1 silencing in ES reduced MEK1/2 and ERK1/2 phosphorylation. Accordingly, chemical inhibition of MEK1/2 resulted in reduction in MMP-9 expression and activity that correlated with reduced migration and invasion. IQ Motif Containing GTPase Activating Protein 1 (IQGAP1) silencing reduced MEK1/2 and ERK1/2 phosphorylation and MMP-9 expression. Furthermore, IQGAP1 silenced cells showed a marked decrease in their migratory and invasive capacity. We demonstrated that CAV1 and IQGAP1 localize in close proximity at the cellular edge, thus IQGAP1 could be the connecting node between CAV1 and MEK/ERK in ES metastatic phenotype. Analysis of the phosphorylation profile of CAV1-silenced cells showed a decrease of p-ribosomal protein S6 (RPS6). RPS6 can be phosphorylated by p90 ribosomal S6 kinases (RSK) proteins. CAV1-silenced cells showed reduced levels of p-RSK1 and treatment with U0126 provoked the same effect. Despite not affecting ERK1/2 and RPS6 phosphorylation status neither MMP-9 expression nor activity, RSK1 silencing resulted in a reduced migratory and invasive capacity in vitro and reduced incidence of metastases in vivo in a novel orthotopic model. The present work provides new insights into CAV1-driven metastatic process in ES unveiling novel key nodes.

The importance of being dead: cell death mechanisms assessment in anti-sarcoma therapy.

Cell death can occur through different mechanisms, defined by their nature and physiological implications. Correct assessment of cell death is crucial for cancer therapy success. Sarcomas are a large and diverse group of neoplasias from mesenchymal origin. Among cell death types, apoptosis is by far the most studied in sarcomas. Albeit very promising in other fields, regulated necrosis and other cell death circumstances (as so-called "autophagic cell death" or "mitotic catastrophe") have not been yet properly addressed in sarcomas. Cell death is usually quantified in sarcomas by unspecific assays and in most cases the precise sequence of events remains poorly characterized. In this review, our main objective is to put into context the most recent sarcoma cell death findings in the more general landscape of different cell death modalities.

Prospects for MEK inhibitors for treating cancer.

INTRODUCTION: The MAPK pathway is a signaling network that plays a key role in many normal cellular processes and in a large number of human malignancies. One of its effectors, MEK, is essential for the carcinogenesis of different tumors. In recent years, several drugs able to inhibit MEK have been assessed in clinical trials. Trametinib has recently become the first MEK inhibitor licensed for cancer treatment (advanced melanoma). AREAS COVERED: We comprehensively review the safety and clinical efficacy of the family of MEK inhibitors, either alone or in combination with other drugs. We discuss data ranging from the Phase III trial of trametinib in melanoma to the most recent drugs with early signs of antitumor activity. In addition, we explain the reasons for the unsuccessful results of the early trials with MEK inhibitors and provide a view of their role in cancer treatment in forthcoming years. EXPERT OPINION: MEK inhibitors are a potentially safe and active treatment option for the treatment of many human malignancies. The information provided by a large series of studies currently ongoing will be very valuable in order to optimize their use. Adequate selection of patients is crucial for achieving successful results with these compounds.

Caveolin-1 is down-regulated in alveolar rhabdomyosarcomas and negatively regulates tumor growth.

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood and adolescence. Despite advances in therapy, patients with histological variant of rhabdomyosarcoma known as alveolar rhabdomyosarcoma (ARMS) have a 5-year survival of less than 30%. Caveolin-1 (CAV1), encoding the structural component of cellular caveolae, is a suggested tumor suppressor gene involved in cell signaling. In the present study we report that compared to other forms of rhabdomyosarcoma (RMS) CAV1 expression is either undetectable or very low in ARMS cell lines and tumor samples. DNA methylation analysis of the promoter region and azacytidine-induced re-expression suggest the involvement of epigenetic mechanisms in the silencing of CAV1. Reintroduction of CAV1 in three of these cell lines impairs their clonogenic capacity and promotes features of muscular differentiation. In vitro, CAV1-expressing cells show high expression of Caveolin-3 (CAV3), a muscular differentiation marker. Blockade of MAPK signaling is also observed. In vivo, CAV1-expressing xenografts show growth delay, features of muscular differentiation and increased cell death. In summary, our results suggest that CAV1 could function as a potent tumor suppressor in ARMS tumors. Inhibition of CAV1 function therefore, could contribute to aberrant cell proliferation, leading to ARMS development.

EphA2-induced angiogenesis in ewing sarcoma cells works through bFGF production and is dependent on caveolin-1.

Angiogenesis is the result of the combined activity of the tumor microenvironment and signaling molecules. The angiogenic switch is represented as an imbalance between pro- and anti-angiogenic factors and is a rate-limiting step in the development of tumors. Eph receptor tyrosine kinases and their membrane-anchored ligands, known as ephrins, constitute the largest receptor tyrosine kinase (RTK) subfamily and are considered a major family of pro-angiogenic RTKs. Ewing sarcoma (EWS) is a highly aggressive bone and soft tissue tumor affecting children and young adults. As other solid tumors, EWS are reliant on a functional vascular network for the delivery of nutrients and oxygen and for the removal of waste. Based on the biological roles of EphA2 in promoting angiogenesis, we explored the functional role of this receptor and its relationship with caveolin-1 (CAV1) in EWS angiogenesis. We demonstrated that lack of CAV1 results in a significant reduction in micro vascular density (MVD) on 3 different in vivo models. In vitro, this phenomenon correlated with inactivation of EphA2 receptor, lack of AKT response and downregulation of bFGF. We also demonstrated that secreted bFGF from EWS cells acted as chemoattractant for endothelial cells. Furthermore, interaction between EphA2 and CAV1 was necessary for the right localization and signaling of the receptor to produce bFGF through AKT and promote migration of endothelial cells. Finally, introduction of a dominant-negative form of EphA2 into EWS cells mostly reproduced the effects occurred by CAV1 silencing, strongly suggesting that the axis EphA2-CAV1 participates in the promotion of endothelial cell migration toward the tumors favoring EWS angiogenesis.

Circuito de alta resolución en el diagnóstico de la incontinencia fecal. Satisfacción de los pacientes / High-resolution circuit for the diagnosis of faecal incontinence. Patient satisfaction

Introducción: La incontinencia fecal (IF), pese a su elevada prevalencia, sigue estando infravalorada e infradiagnosticada. La potencial afectación psicológica, el tabú asociado y el amplio abanico de síntomas hacen del diagnóstico y tratamiento un reto para el cirujano colorrectal. El objetivo de este estudio es describir un nuevo circuito de atención especializado, el circuito de alta resolución (CAR) para tratar la IF, y evaluar la satisfacción de los pacientes. Métodos: Se realiza una descripción de la organización del CAR. Se analizan los datos demográficos y clínicos de los pacientes incluidos en el CAR entre febrero de 2014 y junio de 2016. Se reportan, además, los resultados de una encuesta de satisfacción sobre el CAR realizada a los pacientes incluidos. Resultados: Durante el periodo de estudio se realizaron 321 primeras visitas: 65% (210) por IF (81% mujeres; mediana de edad 66 años). El tiempo mediano de evolución de la IF fue de 24 (rango 4-540) meses. El 79% de los pacientes (165) realizaron el CAR. El 62% respondieron a la encuesta. De estos, solo un 32% (33) habían consultado por este problema en otros centros. La mayoría, 88% (90) consideró preferible el hecho de que hicieran las pruebas diagnósticas el mismo día de la visita. El 94% (96) quedó satisfecho con la información recibida sobre la IF, valorando la consulta con una mediana de 10 (5-10) sobre 10. Conclusión: Con el CAR, el paciente pasa alrededor de 2 h en las consultas externas del hospital, completando el proceso diagnóstico en el mismo día. Los resultados de satisfacción confirman que los pacientes en su mayoría prefieren este sistema (AU)

Introduction: Despite its high prevalence, faecal incontinence (FI) is still underrated and underdiagnosed. Moreover, diagnosis and subsequent treatment can be a challenge for the colorectal surgeon because of its associated social taboo and embarrassment, and the wide range of symptoms. The aim of the present study is to describe a new high-resolution circuit (HRC) for FI diagnosis, that was implemented at our center and to evaluate patient satisfaction. Methods: The structure and organization of the HRC are described. Demographic and clinical data of the patients included in the HRC between February 2014 and June 2016 were collected. Moreover, patients’ satisfaction was measured through a structured survey. Results: A total of 321 patients were evaluated in our pelvic floor outpatients clinic during the study period: 65% (210) of them had FI (81% women, median age 66 years). The mean time since FI onset was 24 (range 4-540) months. A total of 79% (165) of the patients were included in the HRC. 62% of them responded to the survey. Of these, only 32% (33) had consulted for FI before coming to our centre. The majority, 88% (90) considered that performing the 2diagnostic tests the same day of the visit was a very good option. And 94% (96) were satisfied with the information received on their FI, with a median satisfaction value of 10 (5-10). Conclusion: With the HRC, the patient spends about 2h in the outpatient clinic of the hospital, but leaves with the complete diagnostic process performed. The satisfaction survey confirms that most patients prefer this system (AU)

2-deoxyglucose induces Noxa-dependent apoptosis in alveolar rhabdomyosarcoma.

Alveolar and embryonal rhabdomyosarcomas are childhood tumors that do not respond well to current chemotherapies. Here, we report that the glycolytic inhibitor 2-deoxyglucose (2-DG) can efficiently promote cell death in alveolar, but not embryonal, rhabdomyosarcoma cell lines. Notably, 2-DG also induced cell differentiation accompanied by downregulation of PAX3/FOXO1a, the chromosome translocation-encoded fusion protein that is a central oncogenic driver in this disease. Cell death triggered by 2-DG was associated with its ability to activate Bax and Bak. Overexpression of the antiapoptotic Bcl-2 homologues Bcl-x(L) and Mcl-1 prevented apoptosis, indicating that cell death proceeds through the mitochondrial pathway. Mechanistic investigations indicated that Mcl-1 downregulation and Noxa upregulation were critical for 2-DG-induced apoptosis. In addition, 2-DG promoted eIF2α phosphorylation and inactivation of the mTOR pathway. Mcl-1 loss and cell death were prevented by downregulation of the endoplasmic reticulum (ER) stress-induced protein ATF4 and by incubating cells in the presence of mannose, which reverted 2-DG-induced ER stress but not ATP depletion. Thus, energetic stresses created by 2-DG were not the primary cause of cell death. Together, our findings suggest that glycolysis inhibitors such as 2-DG may be highly effective in treating alveolar rhabdomyosarcoma and that Noxa could offer a prognostic marker to monitor the efficacy of such agents.

Caveolin-1 in sarcomas: friend or foe?

Sarcomas represent a heterogeneous group of tumors with a complex and difficult reproducible classification. Their pathogenesis is poorly understood and there are few effective treatment options for advanced disease. Caveolin-1 is a multifunctional scaffolding protein with multiple binding partners that regulates multiple cancer-associated processes including cellular transformation, tumor growth, cell death and survival, multidrug resistance, angiogenesis, cell migration and metastasis. However, ambiguous roles have been ascribed to caveolin-1 in signal transduction and cancer, including sarcomas. In particular, evidence indicating that caveolin-1 function is cell context dependent has been repeatedly reported. Caveolin-1 appears to act as a tumor suppressor protein at early stages of cancer progression. In contrast, a growing body of evidence indicates that caveolin-1 is up-regulated in several multidrug-resistant and metastatic cancer cell lines and human tumor specimens. This review is focused on the role of caveolin-1 in several soft tissue and bone sarcomas and discusses the use of this protein as a potential diagnostic and prognostic marker and as a therapeutic target.

Caveolin-1 modulates the ability of Ewing's sarcoma to metastasize.

Metastasis is the final stage of tumor progression and is thought to be responsible for up to 90% of deaths associated with solid tumors. Caveolin-1 (CAV1) regulates multiple cancer-associated processes related to malignant tumor progression. In the present study, we tested the hypothesis that CAV1 modulates the metastatic ability of cells from the Ewing's sarcoma family of tumors (ESFT). First, we analyzed the expression of CAV1 by immunostaining a tissue microarray containing 43 paraffin-embedded ESFT tumors with known EWS translocations. Even though no evidence was found for a significant association between CAV1 expression and stage, size or tumor site, all metastatic samples (10 of 10) had significantly high CAV1 expression, suggesting that high CAV1 content could positively contribute to enhance ESFT metastasis. To determine the effect of CAV1 on the migratory and invasive capabilities of ESFT cells, we knocked down CAV1 expression in TC252 and A673 cells by stably transfecting a previously validated shRNA construct. In vitro, migration and invasion assays showed that for both cell lines, CAV1 knocked-down cells migrated and invaded significantly less (P ≤ 0.01) than control cells. Moreover, control A673 cells introduced into BALB/c nude mice by tail vein injection strongly colonized the lungs. In contrast, animals injected with CAV1 knocked-down cells showed either no incidence of metastasis or developed lung metastases after a significant delay (P < 0.0001). Finally, we show that the molecular mechanisms by which CAV1 carries out its key role in regulating ESFT metastasis involve matrix metalloproteinase production and activation as well as the control of the expression of SPARC, a known determinant of lung colonization.

The receptor tyrosine kinase EPHB4 has tumor suppressor activities in intestinal tumorigenesis.

Colorectal cancer is the second cause of cancer-related death in the western world, and although the genetic and molecular mechanisms involved in the initiation and progression of these tumors are among the best characterized, there are significant gaps in our understanding of this disease. The role of EPHB signaling in colorectal cancer has only recently been realized. Here, we use animal models to investigate the role of EphB4 in intestinal tumorigenesis. Modulation of EPHB4 levels in colon cancer cell lines resulted in significant differences in tumor growth in a xenograft model, with low levels of EPHB4 associated with faster growth. In addition, using a genetic model of intestinal tumorigenesis where adenomatous polyposis coli (Apc) mutations lead to initiation of the tumorigenic process (Apc(min) mice), we show that inactivation of a single allele of EphB4 results in higher proliferation in both the normal epithelium and intestinal tumors, significantly larger tumors in the small intestine, and a 10-fold increase in the number of tumors in the large intestine. This was associated with a 25% reduction in the lifespan of Apc(min) mice (P < 0.0001). Gene expression analysis showed that EphB4 mutations result in a profound transcriptional reprogramming, affecting genes involved in cell proliferation, remodeling of the extracellular matrix, and cell attachment to the basement membrane among other functional groups of genes. Importantly, in agreement with the expression profiling experiments, using an in vitro assay, we show that loss of EPHB4 in colon cancer cells results in a significantly increased potential to invade through a complex extracellular matrix. Collectively, these results indicate that EphB4 has tumor suppressor activities and that regulation of cell proliferation, extracellular matrix remodeling, and invasive potential are important mechanisms of tumor suppression.