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PDF - 1218K, Four ECCs (IK, AN3CA, MFE-296 and HEC-1A) were treated with Dovitinib (0.05-0.1-0.5-1-2.5 μmol/L) for 72 hours. Cells were stained with Hoechst. The graph on the right shows the percentage of cells displaying apoptotic nuclei in each condition.

PDF - 51K, Analysis of Variance tables. Degrees of freedom (Df), sum of squares (SS), mean sum of squares (Mean SS) and corresponding F statistic and p-value are shown.

Mutations in fibroblast growth factor receptor 2 (FGFR2) have been recently described as a molecular-specific feature in endometrial carcinomas and the presence of activated FGFR2 mutations is associated with poor prognosis. For that reason, inhibition of FGFR2 could be a therapeutic target in the treatment of endometriod carcinomas. In this work, we investigated the antitumoral activity of dovitinib (a multiple kinase inhibitor) in human endometrial cancer cell (ECC) lines. We found that dovitinib caused cell growth arrest, loss of clonogenic growth, and cell-cycle arrest in FGFR2-mutated ECCs in in vitro and in vivo experiments. Next, we investigated the mechanistic basis of dovitinib effects. We could determine that dovitinib modified expression levels of well-known key cell-cycle regulatory proteins that induce cellular senescence. To further investigate the role of dovitinib, we analyzed its effect on estrogen receptor α (ER-α) expression. Surprisingly, we discovered that dovitinib enhances ER-α expression in FGFR2-mutant ECCs. Because blocking one signaling pathway is often not sufficient to cause total tumor regression and the effectiveness of individual inhibitors is often short-lived, we examined the impact of targeting FGFR2 with dovitinib in combination with a selective ER antagonist, fulvestrant (ICI182.780). Combination of dovitinib plus ICI182.780 resulted in a significantly higher inhibition of cell growth than dovitinib treatment alone. These findings suggest that combinatory therapies using dovitinib plus ICI182.780 treatment can be truly effective in patients with endometrial carcinomas carrying FGFR2 mutations. Mol Cancer Ther; 13(4); 776–87. ©2014 AACR.

PDF - 66K, Legends for Supplementary Figures 1 through 5.

PDF - 762K, Four ECCs (IK, AN3CA, MFE-296 and HEC-1A) were treated with Dovitinib (0.05-0.1-0.5-1-2.5 micromol/L) for 48 and 72 hours, and cell viability was assessed by MTT assay. B) Three ECCs (AN3CA, MFE-296 and HEC-1A) were treated with 0.5 micromol/L of Dovitinib or vehicle for 72 h, after quantification of the percentage of BrdU-positive cells was assessed.

PDF - 86K, Endometrial cancer cell lines were treated with ICI 182,780 at 100nM. Total protein lysates were extracted at indicated times after treatment and were subjected to western blot for the expression of ERalpha. Tubulin is shown as at loading control.

PDF - 3065K, Uteri from mice treated during 15 days with Dovitinib (20mg/kg daily) and/or ICI182.780 (5mg/kg) were extracted. Immunostaining for ERalpha and Cyclin D1 was performed to ensure ICI182.780 treatment

PDF - 27K, Representative graphs mean of cell survival (in percentages) for each combination of Dovitinib and ICI. Confidence intervals as estimated from the linear models are shown. Experiments were performed, at least, 3 times on 3 independent days.

Apoptosis; Endometrial cancer; Map kinase Apoptosis; Cáncer endometrial; Mapa quinasa Apoptosi; Càncer d'endometri; Mapa quinasa Endometrial cancer (EC) is the most common type of gynecologic cancer in women of developed countries. Despite surgery combined with chemo-/radiotherapy regimens, overall survival of patients with high-risk EC tumors is poor, indicating a need for novel therapies. The MEK5-ERK5 pathway is activated in response to growth factors and to different stressors, including oxidative stress and cytokines. Previous evidence supports a role for the MEK5-ERK5 pathway in the pathology of several cancers. We investigated the role of ERK5 in EC. In silico analysis of the PanCancer Atlas dataset showed alterations in components of the MEK5-ERK5 pathway in 48% of EC patients. Here, we show that ERK5 inhibition or silencing decreased EGF-induced EC cell proliferation, and that genetic deletion of MEK5 resulted in EC impaired proliferation and reduced tumor growth capacity in nude mice. Pharmacologic inhibition or ERK5 silencing impaired NF-kB pathway in EC cells and xenografts. Furthermore, we found a positive correlation between ERK5 and p65/RELA protein levels in human EC tumor samples. Mechanistically, genetic or pharmacologic impairment of ERK5 resulted in downregulation of NEMO/IKKγ expression, leading to impaired p65/RELA activity and to apoptosis in EC cells and xenografts, which was rescued by NEMO/IKKγ overexpression. Notably, ERK5 inhibition, MEK5 deletion or NF-kB inhibition sensitized EC cells to standard EC chemotherapy (paclitaxel/carboplatin) toxicity, whereas ERK5 inhibition synergized with paclitaxel to reduce tumor xenograft growth in mice. Together, our results suggest that the ERK5-NEMO-NF-κB pathway mediates EC cell proliferation and survival. We propose the ERK5/NF-κB axis as new target for EC treatment. Open Access Funding provided by Universitat Autonoma de Barcelona. The JM Lizcano research group was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO, grant SAF2015-64237-R), and the Spanish Ministry of Science and Innovation (grant PID2019-107561RB-I00), and co-funded by the European Regional Development Fund (ERDF).

Glioblastoma (GBM) is the most common tumor in the central nervous system in adults. This neoplasia shows a high capacity of growth and spreading to the surrounding brain tissue, hindering its complete surgical resection. Therefore, the finding of new antitumor therapies for GBM treatment is a priority. We have previously described that cyclin D1-CDK4 promotes GBM dissemination through the activation of the small GTPases RalA and RalB. In this paper, we show that RalB GTPase is upregulated in primary GBM cells. We found that the downregulation of Ral GTPases, mainly RalB, prevents the proliferation of primary GBM cells and triggers a senescence-like response. Moreover, downregulation of RalA and RalB reduces the viability of GBM cells growing as tumorspheres, suggesting a possible role of these GTPases in the survival of GBM stem cells. By using mouse subcutaneous xenografts, we have corroborated the role of RalB in GBM growth in vivo. Finally, we have observed that the knockdown of RalB also inhibits cell growth in temozolomide-resistant GBM cells. Overall, our work shows that GBM cells are especially sensitive to Ral-GTPase availability. Therefore, we propose that the inactivation of Ral-GTPases may be a reliable therapeutic approach to prevent GBM progression and recurrence. This work was funded by the Catalan Government—AGAUR (2017 SGR-569), Ministerio de Ciencia e Innovaciön (PID2019-104859GB-I00; RTI2018-094739-B-I00; PID2019-104734RB-I00), and by the Xarxa de Bancs de Tumors de Catalunya sponsored by Pla Director d’Oncologia de Catalunya (XBTC). T Cemeli (FPU13/06590), M.Guasch (FPU17/00229), R. Navaridas (FPU18/04480), and M. Ribes (TALENT-IRBLleida) were supported by a pre-doctoral fellowship from Ministerio de Educación, Cultura y Deportes, and from Diputació de Lleida.

Vitamin D (VD) deficiency has been associated with cancer and diabetes. Insulin signaling through the insulin receptor (IR) stimulates cellular responses by activating the PI3K/AKT pathway. PTEN is a tumor suppressor and a negative regulator of the pathway. Its absence enhances insulin signaling leading to hypoglycemia, a dangerous complication found after insulin overdose. We analyzed the effect of VD signaling in a model of overactivation of the IR. We generated inducible double KO (DKO) mice for the VD receptor (VDR) and PTEN. DKO mice showed severe hypoglycemia, lower total cholesterol and increased mortality. No macroscopic tumors were detected. Analysis of the glucose metabolism did not show clear differences that would explain the increased mortality. Glucose supplementation, either systemically or directly into the brain, did not enhance DKO survival. Lipidic liver metabolism was altered as there was a delay in the activation of genes related to β-oxidation and a decrease in lipogenesis in DKO mice. High-fat diet administration in DKO significantly improved its life span. Lack of vitamin D signaling increases mortality in a model of overactivation of the IR by impairing lipid metabolism. Clinically, these results reveal the importance of adequate Vitamin D levels in T1D patients.

Melanoma is a malignant neoplasia that is highly resistant to chemotherapy and radiotherapy and is associated with poor prognosis in advanced stage. Targeting melanoma that harbors the common BRAFV600E mutation with kinase inhibitors, such as vemurafenib, reduces tumor burden, but these tumors frequently acquire resistance to these drugs. We previously proposed that T-type calcium channel (TTCC) expression may serve as a biomarker for melanoma progression and prognosis, and we showed that TTCC blockers reduce migration and invasion rates because of autophagy blockade only in BRAFV600E-mutant melanoma cells. Here, we demonstrated that high expression of the TTCC Cav3.1 isoform is related to autophagic status in vemurafenib-resistant BRAFV600E-mutant melanoma cells and human biopsies, and in silico analysis revealed an enrichment of Cav3.1 expression in post-treatment melanomas. We also demonstrated that the TTCC blocker mibefradil induces apoptosis and impairs migration and invasion via inhibition of autophagy in resistant melanoma cells and mouse xenograft models. Moreover, we identified an association between PTEN status and Cav3.1 expression in these cells as a marker of sensitivity to combination therapy in resistant cells. Together, our results suggest that TTCC blockers offer a potential targeted therapy in resistant BRAFV600E-mutant melanoma and a therapeutic strategy to reduce progression toward BRAF inhibitor resistance.

Simple Summary PTEN is a protein highly altered in endometrial cancer. PTEN mutation or deficiency leads to the activation of other downstream proteins that are important to the development of cancers. In this study, we have identified the SMAD2/3 proteins as targets of PTEN deficiency. We have found that loss of PTEN in endometrial cells leads to SMAD2/3 activation. To investigate the role of SMAD2/3 activation downstream of PTEN deficiency, we have used endometrial cells lacking both PTEN and SMAD2/3 proteins. These cells display even more tumorigenic potential than cells lacking only PTEN. These results suggest that SMAD2/3 acts as an obstacle for cancer development triggered by PTEN loss. Abstract TGF-β has a dichotomous function, acting as tumor suppressor in premalignant cells but as a tumor promoter for cancerous cells. These contradictory functions of TGF-β are caused by different cellular contexts, including both intracellular and environmental determinants. The TGF-β/SMAD and the PI3K/PTEN/AKT signal transduction pathways have an important role in the regulation of epithelial cell homeostasis and perturbations in either of these two pathways’ contributions to endometrial carcinogenesis. We have previously demonstrated that both PTEN and SMAD2/3 display tumor-suppressive functions in the endometrium, and genetic ablation of either gene results in sustained activation of PI3K/AKT signaling that suppresses TGF-β-induced apoptosis and enhances cell proliferation of mouse endometrial cells. However, the molecular and cellular effects of PTEN deficiency on TGF-β/SMAD2/3 signaling remain controversial. Here, using an in vitro and in vivo model of endometrial carcinogenesis, we have demonstrated that loss of PTEN leads to a constitutive SMAD2/3 nuclear translocation. To ascertain the function of nuclear SMAD2/3 downstream of PTEN deficiency, we analyzed the effects of double deletion PTEN and SMAD2/3 in mouse endometrial organoids. Double PTEN/SMAD2/3 ablation results in a further increase of cell proliferation and enlarged endometrial organoids compared to those harboring single PTEN, suggesting that nuclear translocation of SMAD2/3 constrains tumorigenesis induced by PTEN deficiency.

Objectives The PI3K/AKT/mTOR pathway is frequently overactivated in endometrial cancer (EC). We assessed the efficacy of ABTL0812, a novel first-in-class molecule presenting a unique mechanism of action inhibiting this pathway. Methods We investigated the effects of ABTL0812 on proliferation, cell death and modulation of intracellular signaling pathways in a wide panel of endometrioid and non-endometrioid cell lines, an inducible PTEN knock-out murine model, and two patient-derived xenograft murine models of EC. Then, TRIB3 expression was evaluated as potential ABTL0812 pharmacodynamic biomarker in a Phase 1b/2a clinical trial. Results ABTL0812 induced an upregulation of TRIB3 expression, resulting in the PI3K/AKT/mTOR axis inhibition and autophagy cell death induction on EC cells but not in healthy endometrial cells. ABTL0812 treatment also impaired PTEN knock-out cells to progress from hyperplasia to cancer. The therapeutic effects of ABTL0812 were demonstrated in vivo. ABTL0812 increased TRIB3 mRNA levels in whole blood samples of eight EC patients, demonstrating that TRIB3 mRNA could be used as a pharmacodynamic biomarker to monitor the ABTL0812 treatment. Conclusions ABTL0812 may represent a novel and highly effective therapeutic agent by inducing TRIB3 expression and autophagy in EC patients, including those with poorer prognosis.

Simple Summary The PI3K/AKT pathway is involved in cell survival and proliferation. Molecular aberrations and/or hyperactivation of the PI3K-PTEN-AKT axis are frequent in distinct cancer types such as endometrial carcinoma, the most common type of cancer of the female genital tract, and chronic lymphocytic leukemia (CLL), a mature B-cell neoplasm depending on B-cell receptor (BCR) activity, which induces chronical activation of this pathway. The mitochondrial nuclease ENDOG was found to influence PI3K/AKT activity in somatic cells. Our aim was to assess the value of ENDOG gene silencing to block cancer cell proliferation and to evaluate the relevance of ENDOG as prognostic marker. In vivo, in vitro and in silico experiments show that Endog/ENDOG silencing blunts proliferation of tumor cells dependent on high p-AKT/low PTEN activity and that ENDOG has prognostic value in specific cancer types. Abstract EndoG influences mitochondrial DNA replication and is involved in somatic cell proliferation. Here, we investigated the effect of ENDOG/Endog expression on proliferation in different tumor models. Noteworthy, ENDOG deficiency reduced proliferation of endometrial tumor cells expressing low PTEN/high p-AKT levels, and Endog deletion blunted the growth of PTEN-deficient 3D endometrial cultures. Furthermore, ENDOG silencing reduced proliferation of follicular thyroid carcinoma and glioblastoma cell lines with high p-AKT expression. High ENDOG expression was associated with a short time to treatment in a cohort of patients with chronic lymphocytic leukemia (CLL), a B-cell lymphoid neoplasm with activation of PI3K/AKT. This clinical impact was observed in the less aggressive CLL subtype with mutated IGHV in which high ENDOG and low PTEN levels were associated with worse outcome. In summary, our results show that reducing ENDOG expression hinders growth of some tumors characterized by low PTEN activity and high p-AKT expression and that ENDOG has prognostic value for some cancer types.

© 2020 The Author(s)., The apoptotic nuclease EndoG is involved in mitochondrial DNA replication. Previous results suggested that, in addition to regulate cardiomyocyte hypertrophy, EndoG could be involved in cell proliferation. Here, by using in vivo and cell culture models, we investigated the role of EndoG in cell proliferation. Genetic deletion of Endog both in vivo and in cultured cells or Endog silencing in vitro induced a defect in rodent and human cell proliferation with a tendency of cells to accumulate in the G1 phase of cell cycle and increased reactive oxygen species (ROS) production. The defect in cell proliferation occurred with a decrease in the activity of the AKT/PKB-GSK-3β-Cyclin D axis and was reversed by addition of ROS scavengers. EndoG deficiency did not affect the expression of ROS detoxifying enzymes, nor the expression of the electron transport chain complexes and oxygen consumption rate. Addition of the micropeptide Humanin to EndoG-deficient cells restored AKT phosphorylation and proliferation without lowering ROS levels. Thus, our results show that EndoG is important for cell proliferation through the control of ROS and that Humanin can restore cell division in EndoG-deficient cells and counteracts the effects of ROS on AKT phosphorylation., This research was funded by Ministerio de Ciencia e Innovación, Gobierno de España, grant numbers SAF2013-44942-R and PID2019-104509RB-I00 to D.S. and SAF2016-80157-R to X.D.; Fundació La Marató, Catalunya, grant number 20153810 to D.S.; AGAUR, Generalitat de Catalunya, Catalunya, grant number 2014-SGR-1609 to D.S. G.B. holds a contract from the University of Lleida; A.B. contract has been funded by Fundació La Marató TV3 and Diputació de Lleida/IRBLleida.

Many human cancers present Phosphatase and tensin homolog (PTEN) deficiency and between 20 and 30% of colorectal tumors show PTEN loss. The transcription factor, E2 promoter binding factor 1 (E2F-1), exhibits tumor promoter or suppressive functions depending on cellular type and tissue context, but its role in the progression and development of colorectal carcinogenesis was largely unknown. Here, using a tamoxifen-inducible PTEN knockout mouse model, we have demonstrated that loss of PTEN leads to the development of colorectal tumorigenesis through the serrated pathway. Next, we studied PTEN loss-driven colorectal lesions in the context of E2F-1 deficiency in vivo. Our results revealed that monoallelic and biallelic absence of E2F-1 led to an increased incidence and progression of serrated tumorigenesis induced by PTEN loss. Finally, we investigated the mechanisms by which double PTEN/E2F-1 deficiency leads to enhanced tumorigenesis. We found that colorectal tumors from PTEN/E2F-1 double knockout mice and the human colorectal carcinoma cell line HT29 with shRNA-mediated downregulation of PTEN and E2F-1 exhibit hyperactivation of the RAS-MAPK pathway, accumulation of DNA damage and resistance to apoptosis. To date, this is the first preclinical study evaluating the effect of genetic deletion of E2F-1 in colorectal malignancies driven by PTEN deficiency. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

PTEN is one of the most frequently mutated genes in human cancers. The frequency of PTEN alterations is particularly high in endometrial carcinomas. Loss of PTEN leads to dysregulation of cell division, and promotes the accumulation of cell cycle complexes such as cyclin D1-CDK4/6, which is an important feature of the tumour phenotype. Cell cycle proteins have been presented as key targets in the treatment of the pathogenesis of cancer, and several CDK inhibitors have been developed as a strategy to generate new anticancer drugs. Palbociclib (PD-332991) specifically inhibits CDK4/6, and it has been approved for use in metastatic breast cancer in combination with letrazole. Here, we used a tamoxifen-inducible Pten knockout mouse model to assess the antitumour effects of cyclin D1 knockout and CDK4/6 inhibition by palbociclib on endometrial tumours. Interestingly, both cyclin D1 deficiency and palbociclib treatment triggered shrinkage of endometrial neoplasias. In addition, palbociclib treatment significantly increased the survival of Pten-deficient mice, and, as expected, had a general effect in reducing tumour cell proliferation. To further analyse the effects of palbociclib on endometrial carcinoma, we established subcutaneous tumours with human endometrial cancer cell lines and primary endometrial cancer xenografts, which allowed us to provide more translational and predictive data. To date, this is the first preclinical study evaluating the response to CDK4/6 inhibition in endometrial malignancies driven by PTEN deficiency, and it reveals an important role of cyclin D-CDK4/6 activity in their development. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Targeted therapies in endometrial cancer (EC) using kinase inhibitors rarely result in complete tumor remission and are frequently challenged by the appearance of refractory cell clones, eventually resulting in disease relapse. Dissecting adaptive mechanisms is of vital importance to circumvent clinical drug resistance and improve the efficacy of targeted agents in EC. Sorafenib is an FDA-approved multitarget tyrosine and serine/threonine kinase inhibitor currently used to treat hepatocellular carcinoma, advanced renal carcinoma and radioactive iodine-resistant thyroid carcinoma. Unfortunately, sorafenib showed very modest effects in a multi-institutional phase II trial in advanced uterine carcinoma patients. Here, by leveraging RNA-sequencing data from the Cancer Cell Line Encyclopedia and cell survival studies from compound-based high-throughput screenings we have identified the lysosomal pathway as a potential compartment involved in the resistance to sorafenib. By performing additional functional biology studies we have demonstrated that this resistance could be related to macroautophagy/autophagy. Specifically, our results indicate that sorafenib triggers a mechanistic MAPK/JNK-dependent early protective autophagic response in EC cells, providing an adaptive response to therapeutic stress. By generating in vivo subcutaneous EC cell line tumors, lung metastatic assays and primary EC orthoxenografts experiments, we demonstrate that targeting autophagy enhances sorafenib cytotoxicity and suppresses tumor growth and pulmonary metastasis progression. In conclusion, sorafenib induces the activation of a protective autophagic response in EC cells. These results provide insights into the unopposed resistance of advanced EC to sorafenib and highlight a new strategy for therapeutic intervention in recurrent EC. This work was supported by MINECO (SAF2016-80157-R), the Fondo de Investigaciones Sanitarias (PI10/00922, PI10/00604, PI13/01339 and PIE13–00022 (Oncoprofile)), Grant 2009SGR794 (Barcelona, Spain), Fundaci on Asociaci on Espa~nola Contra el C ancer (AECC-2011), AECC_- Barcelona and RETICS (RD12/0036/0013). DLN is recipient of a NURF scheme. The funders had no involvement in the study design, execution, analysis or interpretation of data and writing of the manuscript.

Introduction/Background Endometrial cancer (EC) is the most frequent of the infiltrating tumors of female genital tract. Surgical and adjuvant treatments are the cornerstone treatment for EC patients, however, the response rate to standard therapy is very limited, highlighting the need for novel and efficient treatments. ABTL0812, a small first-in-class molecule, induces cancer cell death by inhibiting the PI3K/AKT/mTOR pathway (frequently overactivated in EC) and inducing endoplasmic reticulum stress (ER-Stress). Objective Assess the preclinical efficacy of ABTL0812 in EC. Methodology We studied ABTL0812 treatment on viability, autophagy and apoptosis in a wide panel of EC cell lines and in 3D-murine endometrial organoids. ABTL0812 efficacy was evaluated in tumor onset and progression in a tamoxifen-inducible PTEN-KO murine model and cell line- or patient-derived xenograft (PDX) models. TRIB3 mRNA levels were evaluated in blood from EC patients recruited in ongoing Phase 1b/2a clinical trial. Results We demonstrated that ABTL0812 treatment in vitro reduced viability, sensitized cancer cells and induced autophagy through ER-stress induction and PI3K/AKT/mTORC1 axis inhibition. In murine PTEN-KO cells, ABTL0812 decreased proliferation and induced nuclear fragmentation/condensation and caspase activation. ABTL0812 in vivo therapeutic benefit was confirmed, leading to a marked reduction in tumor growth (p Conclusion Our results demonstrated that ABTL0812 treatment promoted autophagy followed by activation of the pro-apoptotic pathway. Collectively, we provided strong preclinical evidences of the therapeutic benefit of ABTL0812 as monotherapy or in combination with current first-line treatment in EC. Our findings present a novel and clinically applicable therapeutic strategy for EC and suggest the potential use of TRIB3 as a pharmacodynamic biomarker to monitor ABTL0812 treatment. Disclosure Sonia Sole-Sanchez, Pau Munoz-Guardiola, Elisabet Megias-Roda, Hector Perez-Montoyo, Jose Alfon, Marc Yeste-Velasco, Carles Domenech are Ability Pharmaceuticals employees. Carles Domenech CD holds shares of the Company. Jose Miguel Lizcano is member of its Scientific Advisory Board. Antonio Gil-Moreno, Isidre Felip, Cristian Pablo Moiola, Cristina Megino-Luque, Carlos Lopez-Gil, Silvia Cabrera, Maria Santacana, Xavier Dolcet, Armando Reques, Ana Oaknin, Victor Rodriguez-Freixinos Xavier Matias-Guiu, Eva Colas, Nuria Eritja, declare no conflicts of interest.

Melanoma is a malignant neoplasia that is highly resistant to chemotherapy and radiotherapy and is associated with poor prognosis in advanced stage. Targeting melanoma that harbors the common BRAF

Since its discovery in the late 1990s, Pten has turned out to be one of the most important tumor suppressor genes. Pten loss results in increased activation of the phosphatidylinositol 3-kinase/Akt signaling pathway, which is associated with increased proliferation, survival, and neoplastic growth. Here, we have addressed the effects of conditional deletion of Pten in hematopoietic cells by crossing Pten conditional knockout mice with a knock-in mouse expressing the Cre recombinase in the CD45 locus. CD45 is also known as leukocyte common antigen, and it is expressed in virtually all white cells and in hematopoietic stem cells. Using a reporter mouse, we demonstrate that CD45:Cre mouse displays recombinase activity in both myeloid and lymphoid cells. However, deletion of Pten in CD45-expressing cells induces development of T-cell acute lymphoblastic leukemia and lymphoma, but not other hematologic malignancies.

Many human cancers present Phosphatase and tensin homolog (PTEN) deficiency and between 20 and 30% of colorectal tumors show PTEN loss. The transcription factor, E2 promoter binding factor 1 (E2F-1), exhibits tumor promoter or suppressive functions depending on cellular type and tissue context, but its role in the progression and development of colorectal carcinogenesis was largely unknown. Here, using a tamoxifen-inducible PTEN knockout mouse model, we have demonstrated that loss of PTEN leads to the development of colorectal tumorigenesis through the serrated pathway. Next, we studied PTEN loss-driven colorectal lesions in the context of E2F-1 deficiency in vivo. Our results revealed that monoallelic and biallelic absence of E2F-1 led to an increased incidence and progression of serrated tumorigenesis induced by PTEN loss. Finally, we investigated the mechanisms by which double PTEN/E2F-1 deficiency leads to enhanced tumorigenesis. We found that colorectal tumors from PTEN/E2F-1 double knockout mice and the human colorectal carcinoma cell line HT29 with shRNA-mediated downregulation of PTEN and E2F-1 exhibit hyperactivation of the RAS-MAPK pathway, accumulation of DNA damage and resistance to apoptosis. To date, this is the first preclinical study evaluating the effect of genetic deletion of E2F-1 in colorectal malignancies driven by PTEN deficiency. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

In this study, we first aimed to evaluate the effects in vitro and in vivo, of the Hsp90 inhibitor NVP-AUY922, in endometrial cancer (EC). We also aimed to track nuclear factor kappa B (NF-κB) signalling, a key pathway involved in endometrial carcinogenesis and to check whether NVP-AUY922 treatment modulates it both in vitro and in vivo. I n vitro effects of NVP-AUY922 on EC cell growth and the signalling pathways were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic assays, Western Blot and luciferase assay. NVP-AUY922 effect on Ishikawa (IK) xenograft growth was evaluated in vivo, and NF-κB activity was monitored using bioluminescence imaging. NVP-AUY922 inhibited the growth of three endometrial cell lines tested in vitro. In vivo, NVP-AUY922 reduced tumour growth of 47 % (p = 0.042) compared to control condition. Moreover, the bioluminescence signal of the tumours harbouring IK NF-κB-LUC cells was significantly reduced in NVP-AUY922-treated animals compared to untreated ones. NVP-AUY922 reduced EC tumour growth and NF-κB signalling both in vitro and in vivo. As therapeutic resistance of EC remains a challenge for oncologists nowadays, we think that NVP-AUY922 represents a valid alternative to conventional chemotherapy, and we believe that this approach for assessing and tracking the activation of NF-κB pathway may be of therapeutic benefit.

PTEN is an important tumor suppressor gene. Interpreting PTEN deficiency in the appropriate microscopic context of cancer may be important to understand its role in tumor development and progression. This may be particularly relevant in heterogeneous tumors. Here, we discuss the usefulness of 3D cultures in understanding the consequences of PTEN inactivation in tissue architecture. Afterwards, we discuss the role of immunohistochemistry and fluorescent in situ hybridization in assessing PTEN loss in tumors. In this review, endometrial carcinoma is used as a model.

Endometrial carcinomas, the most common malignant tumour of the female genital tract, are usually diagnosed at an early stage with uterine-confined disease and an overall favourable prognosis. However, up to 20% of endometrial carcinomas will end up in recurrent disease, associated with a drop in survival and representing the major clinical challenge. Management of this group of risk patients relies on robust biomarkers that may predict which endometrial carcinomas will relapse. For this, we performed a proteomic analysis comparing primary lesions with recurrences and identified ANXA2 as a potential biomarker associated with recurrent disease that we further validated in an independent series of samples by immunohistochemistry. We demonstrated in vitro a role for ANXA2 in the promotion of metastasis rather than interfering with sensitivity to radio/chemotherapy. In addition, ANXA2 silencing resulted in a reduced metastatic pattern in a mice model of endometrial cancer dissemination, with a limited presence of circulating tumor cells. Finally, a retrospective study in a cohort of 93 patients showed that ANXA2 effectively predicted those endometrioid endometrial carcinomas that finally recurred. Importantly, ANXA2 demonstrated a predictive value also among low risk Stage I endometrioid endometrial carcinomas, highlighting the clinical utility of ANXA2 biomarker as predictor of recurrent disease in endometrial cancer. Retrospective and prospective studies are ongoing to validate ANXA2 as a potential tool for optimal stratification of patients susceptible to receive radical surgery and radio/chemotherapy.

Vitamin D (VD) deficiency has been suggested as a risk factor for cancer. One recognized mechanism is that the low-serum 25-hydroxyvitamin D (25(OH)D) of VD deficiency reduces intratumoral 25(OH)D conversion to 1α,25-dihydroxyvitamin D (1,25D, the hormonal form of VD), compromising 1,25D-VD receptor (VDR) antitumoral actions. Reduced tumoral VDR and increased CYP24A1, the enzyme that degrades 1,25D and 25(OH)D, further worsen cancer progression. Importantly, in cells expressing CYP27A1 and/or CYP2R1, which convert inert VD into 25(OH)D, low-serum VD may reduce intratumoral 25(OH)D synthesis thereby compromising VDR antitumoral actions because 25(OH)D can activate the VDR directly and enhance 1,25D-VDR action. Therefore, this study examined whether abnormal endometrial expression of CYP27A1 and/or CYP2R1 may impair VDR-antiproliferative properties in endometrial carcinoma (EC). Immunohistochemical analysis of tissue microarrays of normal human endometrium (NE; n=60) and EC (n=157) showed the expected lower VDR expression in EC (P=0.0002). Instead, CYP24A1 expression was lower in EC compared with NE, while CYP27A1 and CYP2R1 expressions were higher (P=0.0002; P=0.03). Furthermore, in NE and EC, CYP2R1 and CYP27A1 expression correlated directly with nuclear VDR levels, an indicator of ligand-induced VDR activation, and inversely with the proliferation marker Ki67. Accordingly, in the endometrioid carcinoma cell lines IK, RL95/2 and HEC1-A, which express VDR, CYP27A1, and CYP2R1, VD efficaciously reduced cell viability and colony number, with a time course that paralleled actual increases in both intracellular 25(OH)D and nuclear VDR levels. Thus, VD may protect from EC progression in part through increased intratumoral 25(OH)D production by CYP27A1 and CYP2R1 for autocrine/paracrine enhancement of 1,25D-VDR-antiproliferative actions.

Aims: To check the usefulness of a standardized protocol of PTEN FISH in 31 endometrial carcinomas (ECs) in comparison with SNP array (SNPA), multiplex ligation-dependent probe amplification (MLPA), and immunohistochemistry. Methods and results: Fluorescence in-situ hybridization analysis showed two PTEN copies in 17 cases, three copies in nine cases, hemizygous deletion in two cases, and diverse cell populations with different PTEN copy number in three cases. A good correlation was seen between FISH and SNPA, particularly in cases with three copies. FISH identified two cases with entire deletion of chromosome 10, but did not identify a focal deletion of PTEN. Five cases with PTEN deletion and duplication of the second allele by SNPA were interpreted as normal by FISH. Concordance between FISH and MLPA was seen in 15 cases with two copies, and in two cases with PTEN deletion. Six cases were interpreted as amplified by MLPA, but showed polyploidy by FISH. FISH was superior to SNPA and MLPA in assessing the tumours with diverse cell populations with different PTEN copies. Conclusions: The results show good concordance between FISH, SNPA and MLPA. SNPA was superior in tumours with deletion of one copy and duplication of the second allele. FISH was superior in assessing tumour heterogeneity. The study was supported by a research agreement with Dako, Denmark. The research team was also supported by grants FIS PI100922, Fundacion Mutua Madrilena AP75732010, 2009SGR794, RD12/0036/ ~ 0013, Fundacion Asociaci on Espa nola contra el Can- ~ cer, Programa de Intensificacion de la Investigaci on, Instituto Carlos III, Verelst Baarmoederkankerfonds, Leuven, and ENITEC (European Network for Individualized Treatment of Endometrial Carcinoma). F. Amant is senior researcher for the research fund Flandersb (FWO). Tumour samples were obtained with the support of Xarxa Catalana de Bancs de Tumours, and Plataforma de Biobancos ISCIII (PT13/ 0010/0014).

Mutations in fibroblast growth factor receptor 2 (FGFR2) have been recently described as a molecular-specific feature in endometrial carcinomas and the presence of activated FGFR2 mutations is associated with poor prognosis. For that reason, inhibition of FGFR2 could be a therapeutic target in the treatment of endometriod carcinomas. In this work, we investigated the antitumoral activity of dovitinib (a multiple kinase inhibitor) in human endometrial cancer cell (ECC) lines. We found that dovitinib caused cell growth arrest, loss of clonogenic growth, and cell-cycle arrest in FGFR2-mutated ECCs in in vitro and in vivo experiments. Next, we investigated the mechanistic basis of dovitinib effects. We could determine that dovitinib modified expression levels of well-known key cell-cycle regulatory proteins that induce cellular senescence. To further investigate the role of dovitinib, we analyzed its effect on estrogen receptor α (ER-α) expression. Surprisingly, we discovered that dovitinib enhances ER-α expression in FGFR2-mutant ECCs. Because blocking one signaling pathway is often not sufficient to cause total tumor regression and the effectiveness of individual inhibitors is often short-lived, we examined the impact of targeting FGFR2 with dovitinib in combination with a selective ER antagonist, fulvestrant (ICI182.780). Combination of dovitinib plus ICI182.780 resulted in a significantly higher inhibition of cell growth than dovitinib treatment alone. These findings suggest that combinatory therapies using dovitinib plus ICI182.780 treatment can be truly effective in patients with endometrial carcinomas carrying FGFR2 mutations. Mol Cancer Ther; 13(4); 776–87. ©2014 AACR.

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.

PTEN is one of the most frequently mutated genes in human cancers. The frequency of PTEN alterations is particularly high in endometrial carcinomas. Loss of PTEN leads to dysregulation of cell division, and promotes the accumulation of cell cycle complexes such as cyclin D1-CDK4/6, which is an important feature of the tumour phenotype. Cell cycle proteins have been presented as key targets in the treatment of the pathogenesis of cancer, and several CDK inhibitors have been developed as a strategy to generate new anticancer drugs. Palbociclib (PD-332991) specifically inhibits CDK4/6, and it has been approved for use in metastatic breast cancer in combination with letrazole. Here, we used a tamoxifen-inducible Pten knockout mouse model to assess the antitumour effects of cyclin D1 knockout and CDK4/6 inhibition by palbociclib on endometrial tumours. Interestingly, both cyclin D1 deficiency and palbociclib treatment triggered shrinkage of endometrial neoplasias. In addition, palbociclib treatment significantly increased the survival of Pten-deficient mice, and, as expected, had a general effect in reducing tumour cell proliferation. To further analyse the effects of palbociclib on endometrial carcinoma, we established subcutaneous tumours with human endometrial cancer cell lines and primary endometrial cancer xenografts, which allowed us to provide more translational and predictive data. To date, this is the first preclinical study evaluating the response to CDK4/6 inhibition in endometrial malignancies driven by PTEN deficiency, and it reveals an important role of cyclin D-CDK4/6 activity in their development. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

Cyclin D1 (Ccnd1) is a proto-oncogen amplified in many different cancers and nuclear accumulation of Ccnd1 is a characteristic of tumor cells. Ccnd1 activates the transcription of a large set of genes involved in cell cycle progress and proliferation. However, Ccnd1 also targets cytoplasmic proteins involved in the regulation of cell migration and invasion. In this work, we have analyzed by immunohistochemistry the localization of Ccnd1 in endometrial, breast, prostate and colon carcinomas with different types of invasion. The number of cells displaying membranous or cytoplasmic Ccnd1 was significantly higher in peripheral cells than in inner cells in both collective and pushing invasion patterns of endometrial carcinoma, and in collective invasion pattern of colon carcinoma. Also, the cytoplasmic localization of Ccnd1 was higher when tumors infiltrated as single cells, budding or small clusters of cells. To evaluate cytoplasmic function of cyclin D1, we have built a variant (Ccnd1-CAAX) that remains attached to the cell membrane therefore sequestering this cyclin in the cytoplasm. Tumor cells harboring Ccnd1-CAAX showed high levels of invasiveness and metastatic potential compared to those containing the wild type allele of Ccnd1. However, Ccnd1- CAAX expression did not alter proliferative rates of tumor cells. We hypothesize that the role of Ccnd1 in the cytoplasm is mainly associated with the invasive capability of tumor cells. Moreover, we propose that subcellular localization of Ccnd1 is an interesting guideline to measure cancer outcome. This work was funded by Spanish Ministry of Education and Science (BFU2010-20293/ BMC and BFU2013-42895-P), Catalan Government (SGR-559), and Fondo de Investigaciones Sanitarias (PI10/00604 and PI13/00263). X.M-G was supported by grants 2014SGR138, RD12/0036/0013, and Fundación Asociación Española contra el Cancer. Tumour samples were obtained with the support of Xarxa Catalana de Bancs de Tumors, and Plataforma de Biobancos ISCIII (PT13/0010/0014). NP. Fusté was supported by a contract from “Fundació Alicia Cuello de Merigó”. I. Felip and T. Cemeli were supported by a predoctoral fellowship from FPU-MINECO.

OBJECTIVE: The PI3K/AKT/mTOR pathway is frequently aberrantly activated in endometrial carcinoma (EC). Temsirolimus is an mTOR inhibitor that has shown clinical activity in EC. We aimed to characterize the biological effects on mTOR pathway of temsirolimus in treatment-naive patients with primary EC, and to identify potential biomarkers associated with a short-term exposure to temsirolimus. MATERIALS AND METHODS: Patients with EC were treated with 4 doses of temsirolimus previous to surgery. The primary objective was the analysis of paired endometrial aspirates and posttreatment (hysterectomy specimens) tumor tissue samples for mTOR downstream effectors p-S6K1 and p-4BEP1 levels by immunohistochemistry. Secondary objectives included analysis of expression of other mTOR-related biomarkers by immunohistochemistry, as well as analysis of the predictive value of mutations in mTOR-related genes. Toxicity was also assessed. RESULTS: Eleven patients were included in the study. p-S6K1 expression was reduced after treatment with temsirolimus in all patients. Variations of the expression of other mTOR-related proteins including p-4BEP1, PTEN, p-AKT, p53, p27, BAD, Bcl-2, Ki67, and cyclin D1 were also observed. Interestingly, the biological effects of the drug were more evident 1 week after the last dose of temsirolimus. Effects were less evident on tumors harboring mutations in NRAS. Toxicity was acceptable, being mucositis the most frequent adverse event. CONCLUSIONS: Short temsirolimus exposure effectively inhibits mTOR pathway in patients with endometrial cancer. p-S6K1 expression is a promising biomarker of sensitivity. The preoperative window opportunity in EC is a realistic scenario for biological knowledge and target development.

Santacana M, Yeramian A, Velasco A, Bergada L, Gatius S, Garcia V, Azueta A, Palacios J, Dolcet X, Oliva E & Matias-Guiu X (2012) Histopathology 60, 460–471 Immunohistochemical features of post-radiation vaginal recurrences of endometrioid carcinomas of the endometrium: role for proteins involved in resistance to apoptosis and hypoxia Aims: Endometrioid carcinoma of the endometrium (EEC) is treated with surgery and radiotherapy. Post-radiation recurrences are associated with increased risk of metastases. Comparison of the expression of genes important in the development and progression of EEC, and others involved in resistance to apoptosis and hypoxia and adaptation to radiation, was performed between post-radiation vaginal recurrences (PVRs) and primary EECs. We tried to reproduce the results by exposing an EEC cell line to hypoxia and radiation. Methods and results: Immunohistochemistry and tissue microarrays were used to compare 24 PVRs with 82 primary EECs. PVRs exhibited increased expression of p53 (P

Epithelial ovarian cancer is the most lethal gynecological malignancy and the fifth leading cause of cancer deaths in women in the Western world. ETS transcription factors are known to act as positive or negative regulators of the expression of genes that are involved in various biological processes, including those that control cellular proliferation, differentiation, apoptosis, tissue remodeling, angiogenesis and transformation. ETV5 belongs to the PEA3 subfamily. PEA3 subfamily members are able to activate the transcription of proteases, matrix metalloproteinases and tissue inhibitor of metalloproteases, which is central to both tumor invasion and angiogenesis. Here, we examined the role of the ETV5 transcription factor in epithelial ovarian cancer and we found ETV5 was upregulated in ovarian tumor samples compared to ovarian tissue controls. The in vitro inhibition of ETV5 decreased cell proliferation in serum-deprived conditions, induced EMT and cell migration and decreased cell adhesion to extracellular matrix components. ETV5 inhibition also decreased cell-cell adhesion and induced apoptosis in anchorage-independent conditions. Accordingly, upregulation of ETV5 induced the expression of cell adhesion molecules and enhanced cell survival in a spheroid model. Our findings suggest that the overexpression of ETV5 detected in ovarian cancer cells may contribute to ovarian tumor progression through the ability of ETV5 to enhance proliferation of ovarian cancer cells. In addition, upregulation of ETV5 would play a role in ovarian cancer cell dissemination and metastasis into the peritoneal cavity by protecting ovarian cancer cells from apoptosis and by increasing the adhesion of ovarian cancer cells to the peritoneal wall through the regulation of cell adhesion molecules.

In vivoandin vitromotoneuron survival depends on the support of neurotrophic factors. These factors activate signaling pathways related to cell survival or inactivate proteins involved in neuronal death. In the present work, we analyzed the involvement of the nuclear factor-κB (NF-κB) pathway in mediating mouse spinal cord motoneuron survival promoted by neurotrophic factors. This pathway comprises ubiquitously expressed transcription factors that could be activated by two different routes: the canonical pathway, associated with IKKα/IKKβ kinase phosphorylation and nuclear translocation RelA (p65)/p50 transcription factors; and the noncanonical pathway, related to IKKα kinase homodimer phosphorylation and RelB/p52 transcription factor activation. In our system, we show that neurotrophic factors treatment induced IKKα and IKKβ phosphorylation and RelA nuclear translocation, suggesting NF-κB pathway activation. Protein levels of different members of the canonical or noncanonical pathways were reduced in a primary culture of isolated embryonic motoneurons using an interference RNA approach. Even in the presence of neurotrophic factors, selective reduction of IKKα, IKKβ, or RelA proteins induced cell death. In contrast, RelB protein reduction did not have a negative effect on motoneuron survival. Together these results demonstrated that the canonical NF-κB pathway mediates motoneuron survival induced by neurotrophic factors, and the noncanonical pathway is not related to this survival effect. Canonical NF-κB blockade induced an increase of Bim protein level and apoptotic cell death. Bcl-xLoverexpression or Bax reduction counteracted this apoptotic effect. Finally, RelA knockdown causes changes of CREB and Smn protein levels.

Sprouty 2 is a key antagonist regulator of receptor tyrosine kinases, and downstream signaling pathways, like fibroblastic growth factor (FGF) and Ras-mitogen-activated protein kinase (RAS-MAPK). By controlling these pathways, sprouty 2 is involved in regulation of cell proliferation, differentiation, and angiogenesis. Alterations in fibroblastic growth factor receptor (FGFR) and members of the RAS-MAPK pathway are frequent in endometrial carcinoma. The expression of sprouty 2 has been found to be decreased in several types of human cancer, by mechanisms of promoter methylation. In the present study, we have assessed the expression of sprouty 2 in endometrial carcinoma, in correlation with sprouty 2 promoter methylation. Sprouty 2 immunohistochemical expression was assessed using 3 different tissue microarrays: one constructed from paraffin blocks of 80 samples of normal endometrium and 2 tissue microarrays containing samples of 157 endometrial carcinoma (1 tissue microarray constructed with 95 endometrial carcinomas previously studied for microsatellite instability and alterations in phosphatase and tensin homolog (PTEN), k-ras, and b-catenin, and 1 tissue microarray containing 62 endometrial carcinoma, which were also subjected to sprouty 2 promoter methylation analysis). The immunohistochemical expression of sprouty 2 was correlated with cellular proliferation (Ki67) and clinicopathologic data. Sprouty 2 promoter methylation was assessed by methylation-specific polymerase chain reaction, with DNA obtained from fresh-frozen samples of endometrial carcinoma and corresponding normal tissues, and correlated with promoter methylation of RAS association domain family-1A (RASSF1A). A highly significant decrease in sprouty 2 immunoexpression was seen in the proliferative phase of normal endometrium (P < .001). Differences were detected between types I and II endometrial carcinoma, but they were not statistically significant. Reduced immunoexpression of sprouty 2 was seen in 19.85% of endometrial carcinoma and was strongly and inversely associated with increased cell proliferation (Ki67; r = -0.367; P = .001). Sprouty 2 promoter methylation was detected in 31 (53.4%) of 58 endometrial carcinomas. Results from our study show that alterations in sprouty 2 may be involved in endometrial carcinogenesis by controlling cell proliferation.

Sorafenib induces apoptosis and enhances Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)-induced cell killing of tumoural cells. We have investigated the effects of the multikinase inhibitor Sorafenib alone or in combination with TRAIL and agonistic Fas antibodies on endometrial carcinoma cells. We have also focused on the search of the differential molecular mechanisms by which Sorafenib induces cell death and the ones involved in sensitisation to TRAIL. In the present study, we show that Sorafenib induces apoptosis of both endometrial cancer cell lines and human primary cultures and sensitises these cells to TRAIL and agonistic Fas antibodies (aFas)-induced apoptosis. However, Raf/MEK/ERK inhibition by Sorafenib was not responsible for Sorafenib cell death or TRAIL sensitisation of endometrial cancer cells. Sorafenib treatment correlated with a downregulation of both FLICE-Inhibitory Protein (FLIP) and myeloid cell leukaemia-1 (Mcl-1), caused by a proteasomal degradation of both proteins. We evaluated the contribution of FLIP and Mcl-1 downregulation in apoptosis triggered by Sorafenib alone or Sorafenib plus TRAIL. Interestingly, cell death caused by Sorafenib was mediated by downregulation of Mcl-1, but not by FLIP. In contrast, we found that Sorafenib sensitisation of endometrial carcinoma cells to TRAIL- and Fas-induced apoptosis was dependent on FLIP but not on Mcl-1 downregulation. Altogether, we discern the dual mechanisms by which Sorafenib causes cell death from those involved in death receptor sensitisation.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family, which mediates apoptosis by the extrinsic pathway. Up-regulation of decoy receptors, DcR1 and DcR2, may result in diminished binding of TRAIL to their functional receptors. DcR1 expression was assessed in normal endometrial tissue (NE) and endometrial carcinoma (EC) samples by immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (PCR). IHC was performed in two tissue microarrays; one composed of 80 samples of NE and a second one constructed from paraffin-embedded blocks of 62 EC. For quantitative real-time RT-PCR analysis, RNA was obtained from 19 NE and 28 EC samples using Trizol. mRNA expression of DcR1 was assessed with Taqman-based assays in an Abi-Prism 700 SDS. Results were correlated with stage, histological type, and grade. By IHC, cytoplasmic expression of DcR1 was frequently seen in NE (79.6%) and varied according to the menstrual cycle. Positive DcR1 immunostaining was also detected in EC (98.1% of the cases) without any specific statistical association with histological type, grade, and stage. By quantitative real-time PCR, all NE had similar levels of DcR1expression (0.8-1.7 RQ), which were considered the basal levels of DcR1 expression in NE. Increased DcR1 expression (or =5-fold higher than the basal levels) was detected in 13 of 28 EC (46.4%). High DcR1 expression levels were found in ECs of different stages: IA, four of 12 (33%); IB, two of four (50%); IC, four of six (66%); and IIA and IIB three of six (50%). Results suggest that DcR1 expression occurs in a subset of EC and may contribute to resistance to TRAIL-induced apoptosis.

In previous studies we have demonstrated that the active form of vitamin D (1,25(OH)(2)D(3)) increases vascular endothelial growth factor (VEGF) expression and release in vascular smooth muscle cells (VSMC) in vitro. However, the mechanism by which 1,25(OH)(2)D(3) increases VEGF production is currently unknown. In this work, we demonstrated binding of vitamin D receptor to two response elements in the VEGF promoter. We performed promoter transactivation analysis and we observed that, in 293T cells, VEGF promoter was activated after vitamin D treatment. Using site-directed mutagenesis we have shown that both response elements are important for VEGF promoter activity. Therefore, the increase in VEGF expression and secretion induced by 1,25(OH)(2)D(3) in VSMC in vitro could be explained by direct binding of the vitamin D receptor, as a transcription factor, to VEGF promoter. These results could explain part of the beneficial effects of vitamin D treatment in renal patients by a possible VEGF-mediated improvement of the endothelial dysfunction.