Publications (14)59.71 Total impact
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Article: Effect of Vinca alkaloids on ERα levels and Estradiol-induced responses in MCF-7 cells
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ABSTRACT: Vinca alkaloids (VAs) such as Vincristine, Vinblastine and Vinorelbine are antineoplastic drugs that inhibit tubulin polymerisation into microtubules, induce mitotic G2/M arrest, activate c-Jun N-terminal kinase (JNK) and induce apoptosis. Although there are many studies evaluating the effect of VAs on breast cancer patients, until now little was known about how these compounds and estradiol signaling pathways might interfere. In this report, we show for the first time that VAs decreased ERα protein levels in the human breast cancer cell line MCF-7; VAs induced a parallel decrease in estrogen receptor mRNA. All the VAs tested inhibited estradiol (E2) mediated transactivation at ERE-driven promoters. E2 inhibited VAs-induced AP1 stimulation in MCF-7, but this inhibition was not observed when E2 is added 24h in advance of VAs treatment. In contrast to the reported preventing effect over taxol-mediated apoptosis, E2 did not prevent VAs-induced cell death and interestingly, addition of E2 24 hours in advance of VAs treatment resulted in an increase of the number of cells undergoing apoptosis. Similar results were observed when E2 is replaced by other proliferation signals such as EGF. These results demonstrate that in the breast cancer cell-line MCF-7, E2-induced proliferation before VAs treatment enhances the apoptotical response to VAs which might have important implications in clinica.Breast Cancer Research and Treatment 04/2012; 98(1):81-89. · 4.43 Impact Factor -
Article: Role of HERG1 potassium channel in both malignant transformation and disease progression in head and neck carcinomas.
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ABSTRACT: Evidence indicates that human ether à-go-go-related gene 1 (HERG1) voltage-gated potassium channels could represent new valuable membrane therapeutic targets and diagnostic/prognostic biomarkers in various cancers. This study is the first to investigate the expression pattern of HERG1 potassium channel subunit in both primary tumors and precancerous lesions to establish its clinical and biological role during the development and progression of head and neck squamous cell carcinomas. HERG1 protein expression was evaluated by immunohistochemistry in paraffin-embedded tissue specimens from 133 patients with laryngeal/hypopharyngeal squamous cell carcinomas and 75 patients with laryngeal dysplasia, and correlated with clinical data. Our findings demonstrate that HERG1 is frequently aberrantly expressed in a high percentage of primary tumors (87%), whereas expression was negligible in both stromal cells and normal-adjacent epithelia. HERG1 expression increased during head and neck squamous cell carcinoma progression and was significantly associated with lymph node metastasis (P=0.04), advanced disease stages (P<0.001), regional tumor recurrence (P=0.004), distant metastasis (P=0.03) and reduced disease-specific survival (P=0.012, log-rank test). HERG1-positive expression was also detected in 31 (41%) of 75 laryngeal dysplasias. Interestingly, HERG1 expression increased with the grade of dysplasia; however, HERG1 expression but not histology correlated significantly with increased laryngeal cancer risk (P=0.007). In addition, functional studies in head and neck squamous cell carcinoma-derived cell lines further revealed that HERG1 expression promotes anchorage-dependent and -independent cell growth and invasive capability, although independently of its ion-conducting function. Our data demonstrate that HERG1 expression is a biologically and clinically relevant feature in head and neck squamous cell carcinoma progression and also during malignant transformation, and a promising candidate as cancer risk marker and therapeutic target for head and neck squamous cell carcinoma prevention and treatment.Modern Pathology 03/2012; 25(8):1069-78. · 4.79 Impact Factor -
Article: Clinical significance of annexin A2 downregulation in oral squamous cell carcinoma.
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ABSTRACT: The purpose of this study was to determine the expression of Annexin A2 (ANXA2) in normal oral epithelium and in oral carcinomas to correlate these findings with prognostically relevant variables. ANXA2 expression in normal oral mucosa and in 106 oral squamous cell carcinomas was examined by immunohistochemistry. ANXA2 expression was detected in basal and suprabasal cell layers of normal epithelium, and immunostaining was preferentially membrane-localized. ANXA2 expression was significantly correlated with the histopathological grade, tumor size, and recurrence, but ANXA2 expression was not an independent prognostic factor. The reduction of ANXA2 expression in poorly differentiated tumors is expected to result in a loss of function aimed at the coordination of membrane signaling enzyme complexes. The consequences may manifest as an alteration of epithelial tissue growth and remodeling which eventually exert an influence on tumor progression and metastasis.Head & Neck 04/2011; 33(12):1708-14. · 2.40 Impact Factor -
Article: Regulation of the expression of death receptors and their ligands by melatonin in haematological cancer cell lines and in leukaemia cells from patients.
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ABSTRACT: Incorporation of new therapeutic agents remains as a major challenge for treatment of patients with malignant haematological disorders. Melatonin is an indolamine without relevant side effects. It has been shown previously to exhibit synergism with several chemotherapeutic drugs in Ewing sarcoma cells by potentiating the extrinsic pathway of apoptosis. It also sensitizes human glioma cells against TRAIL by increasing DR5 expression. Here, we report the induction of cell death by melatonin in several human malignant haematological cell lines through the activation of the extrinsic pathway of apoptosis. Such activation was mediated by the increase in the expression of the death receptors Fas, DR4 and DR5 and their ligands Fas L and TRAIL, with a remarkable rise in the expression of Fas and Fas L. The cytotoxic effect and the increase in Fas and Fas L were dependent on Akt activation. Results were corroborated in blasts from bone marrow and peripheral blood of acute myeloid leukaemia patients, where melatonin induced cell death and increased both Fas and Fas L expressions. We conclude that melatonin may be considered as a potential antileukaemic agent and its therapeutic use, either alone or in combination with current chemotherapeutic drugs, should be taken into consideration for further research.Journal of Pineal Research 04/2011; 50(3):345-55. · 5.79 Impact Factor -
Article: Down-regulation of annexin A1 and A2 protein expression in intestinal-type sinonasal adenocarcinomas.
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ABSTRACT: Annexins are a structurally related family of calcium- and phospholipid-binding proteins that have been implicated in a broad range of molecular and cellular processes. The altered expression of individual annexins has been implicated in tumor development and progression. In this study the expression of annexin A1 and annexin A2 was studied by immunohistochemistry in intestinal-type sinonasal adenocarcinoma using a study set of 57 intestinal-type sinonasal adenocarcinomas represented on an intestinal-type sinonasal adenocarcinoma tissue microarray to assess its potential role in the pathogenesis of these tumors. Our results showed that annexin A1 expression was consistently lost in 52 (91%) intestinal-type sinonasal adenocarcinomas, as compared with the normal epithelium. The expression of annexin A2 was more heterogeneous, and only 19 (33%) cases showed annexin A2 negative expression. Annexin A2 expression was correlated with the histopathological type, being lower in the mucinous type (P = .022). The loss of annexin A2 expression correlated with a reduced survival in univariate analysis (P = .004). However, the impact of annexin A2 expression on patient survival could be an indirect consequence of its association with the histopathological type, since annexin A2 expression was not found to be an independent predictor in multivariate analyses. These results suggest that annexin A1 expression is frequently and commonly lost in intestinal-type sinonasal adenocarcinoma development. Annexin A2 expression is also reduced in intestinal-type sinonasal adenocarcinoma, and this loss of expression is associated to the more aggressive histopathological types.Human pathology 10/2010; 42(1):88-94. · 3.03 Impact Factor -
Article: Expression and clinical significance of the Kv3.4 potassium channel subunit in the development and progression of head and neck squamous cell carcinomas.
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ABSTRACT: The concept of ion channels as membrane therapeutic targets and diagnostic/prognostic biomarkers has attracted growing attention. We therefore investigated the expression pattern and clinical significance of the Kv3.4 potassium channel subunit during the development and progression of head and neck squamous cell carcinomas (HNSCCs). KCNC4 mRNA levels were determined by real-time RT-PCR in both HNSCC tissue specimens and derived cell lines. Kv3.4 protein expression was evaluated by immunohistochemistry in paraffin-embedded tissue specimens from 84 patients with laryngeal/pharyngeal squamous cell carcinomas and 67 patients with laryngeal dysplasias. Molecular alterations were correlated with clinicopathological parameters and patient outcome. Increased KCNC4 mRNA levels were found in 15 (54%) of 28 tumours, compared to the corresponding normal epithelia and varied mRNA levels were detected in 12 HNSCC-derived cell lines analysed. Increased Kv3.4 protein expression was observed in 34 (40%) of 84 carcinomas and also at early stages of HNSCC tumourigenesis. Thus, 35 (52%) of 67 laryngeal lesions displayed Kv3.4-positive staining in the dysplastic areas, whereas both stromal cells and normal adjacent epithelia exhibited negligible expression. No significant correlations were found between Kv3.4-positive expression in HNSCC and clinical data; however, Kv3.4 expression tended to diminish in advanced-stage tumours. Interestingly, patients carrying Kv3.4-positive dysplasias experienced a significantly higher laryngeal cancer incidence than did those with negative lesions (p = 0.0209). In addition, functional studies using HNSCC cells revealed that inhibition of Kv3.4 expression by siRNA leads to the inhibition of cell proliferation via selective cell cycle arrest at the G2/M phase without affecting apoptosis. Collectively, these data demonstrate for the first time that Kv3.4 expression is frequently increased during HNSCC tumourigenesis and correlated significantly with a higher cancer risk. Our findings support a role for Kv3.4 in malignant transformation and provide original evidence for the potential clinical utility of Kv3.4 expression as a biomarker for cancer risk assessment.The Journal of Pathology 08/2010; 221(4):402-10. · 6.32 Impact Factor -
Article: The SWI/SNF chromatin remodeling subunit BAF57 is a critical regulator of estrogen receptor function in breast cancer cells.
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ABSTRACT: Estrogen receptors (ERs) play critical roles in both normal mammary gland development and in the formation and progression of breast tumors, constituting a major therapeutic target for breast cancer treatment. We have previously described that ER transcriptional activity is potentiated by BAF57, a core subunit of the mammalian SWI/SNF chromatin remodeling complex. Here we provide evidence demonstrating an important role for BAF57 as regulator of ER functions in breast cancer cells. Different experimental manipulations leading to the abrogation of BAF57 expression and/or function severely reduced the expression of various endogenous ER target genes and blocked estrogen-stimulated proliferation in ZR-75-1 breast cancer cells. Moreover, using a structure-function analysis, we have defined the protein domains required for the functional interaction between ERalpha and BAF57, including a key region within the hinge of ERalpha that is essential for BAF57 recruitment and its function on ER-mediated transcription. Interestingly, we found that BAF57 is an ER subtype-selective modulator that specifically regulates ERalpha-mediated transcription. Taken together, our results suggest that targeting BAF57 could represent a new way to effectively inhibit the action of ERalpha.Journal of Biological Chemistry 09/2006; 281(32):22656-64. · 4.77 Impact Factor -
Article: Identification of BAF57 mutations in human breast cancer cell lines.
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ABSTRACT: Accumulating genetic and biochemical evidences support a role for the SWI/SNF chromatin-remodeling complex in cancer development and multiple core subunits of these complexes have been found to function as tumor suppressor genes. The core SWI/SNF subunit BAF57 mediates direct interactions with estrogen and androgen receptors (ER and AR) regulating their transcriptional activity. BAF57 gene maps to chromosome band 17 q21 in close proximity to the BRCA1 gene. This locus has been associated with frequent loss of heterozygosity (LOH) and allelic imbalance in breast cancers; however, BRCA1 mutations are rare events in sporadic breast cancer with LOH in the region, suggesting that another tumor suppressor gene resides in this area. All these reasons prompted us to screen for mutations in the BAF57 gene using a panel of the most commonly used human breast cancer cell lines. All cell lines analysed contain wild-type copies of BAF57 gene with the only exception of the breast ductal carcinoma cell line BT549. Sequencing of genomic DNA and cDNA generated from BT549 mRNA demonstrated the presence of a CA dinucleotide insertion in exon 5 of BAF57. The absence of wild-type BAF57 alleles indicates that this is a biallelic inactivating mutation that causes a frameshift and as a consequence a premature stop codon leading to a truncated BAF57 protein. A functional characterisation of the truncated BAF57 showed that it has lost the ability to bind to ER but still binds to the nuclear receptor coactivator SRC1e. Furthermore, we observed that the expression of the truncated BAF57 increased the ability of SRC1e to potentiate transcriptional activation by ERalpha, suggesting that mutations in BAF57 could contribute to the oncogenic transformation in breast cancer cells.Breast Cancer Research and Treatment 08/2006; 98(2):191-8. · 4.43 Impact Factor -
Article: Effect of vinca alkaloids on ERalpha levels and estradiol-induced responses in MCF-7 cells.
[show abstract] [hide abstract]
ABSTRACT: Vinca alkaloids (VAs) such as Vincristine, Vinblastine and Vinorelbine are antineoplastic drugs that inhibit tubulin polymerisation into microtubules, induce mitotic G2/M arrest, activate c-Jun N-terminal kinase (JNK) and induce apoptosis. Although there are many studies evaluating the effect of VAs on breast cancer patients, until now little was known about how these compounds and estradiol signaling pathways might interfere. In this report, we show for the first time that VAs decreased ERalpha protein levels in the human breast cancer cell line MCF-7; VAs induced a parallel decrease in estrogen receptor mRNA. All the VAs tested inhibited estradiol (E2) mediated transactivation at ERE-driven promoters. E2 inhibited VAs-induced AP1 stimulation in MCF-7, but this inhibition was not observed when E2 is added 24 h in advance of VAs treatment. In contrast to the reported preventing effect over taxol-mediated apoptosis, E2 did not prevent VAs-induced cell death and interestingly, addition of E2 24 hours in advance of VAs treatment resulted in an increase of the number of cells undergoing apoptosis. Similar results were observed when E2 is replaced by other proliferation signals such as EGF. These results demonstrate that in the breast cancer cell-line MCF-7, E2-induced proliferation before VAs treatment enhances the apoptotical response to VAs which might have important implications in clinica.Breast Cancer Research and Treatment 08/2006; 98(1):81-9. · 4.43 Impact Factor -
Article: Hey1, a mediator of notch signaling, is an androgen receptor corepressor.
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ABSTRACT: Hey1 is a member of the basic helix-loop-helix-Orange family of transcriptional repressors that mediate Notch signaling. Here we show that transcription from androgen-dependent target genes is inhibited by Hey1 and that expression of a constitutively active form of Notch is capable of repressing transactivation by the endogenous androgen receptor (AR). Our results indicate that Hey1 functions as a corepressor for AF1 in the AR, providing a mechanism for cross talk between Notch and androgen-signaling pathways. Hey1 colocalizes with AR in the epithelia of patients with benign prostatic hyperplasia, where it is found in both the cytoplasm and the nucleus. In marked contrast, we demonstrate that Hey1 is excluded from the nucleus in most human prostate cancers, raising the possibility that an abnormal Hey1 subcellular distribution may have a role in the aberrant hormonal responses observed in prostate cancer.Molecular and Cellular Biology 03/2005; 25(4):1425-36. · 5.53 Impact Factor -
Article: Melatonin, an endogenous-specific inhibitor of estrogen receptor alpha via calmodulin.
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ABSTRACT: Melatonin is an indole hormone produced mainly by the pineal gland. We have previously demonstrated that melatonin interferes with estrogen (E(2)) signaling in MCF7 cells by impairing estrogen receptor (ER) pathways. Here we present the characterization of its mechanism of action showing that melatonin is a specific inhibitor of E(2)-induced ERalpha-mediated transcription in both estrogen response element- and AP1-containing promoters, whereas ERbeta-mediated transactivation is not inhibited or even activated at certain promoters. We show that the sensitivity of MCF-7 cells to melatonin depends on the ERalpha/ERbeta ratio, and ectopic expression of ERbeta results in MCF-7 cells becoming insensitive to this hormone. Melatonin acts as a calmodulin antagonist inducing conformational changes in the ERalpha-calmodulin (CaM) complex, thus impairing the binding of E(2).ERalpha.CaM complex to DNA and, therefore, preventing ERalpha-dependent transcription. Moreover the mutant ERalpha (K302G,K303G), unable to bind calmodulin, becomes insensitive to melatonin. The effect of melatonin is specific since other related indoles neither interact with CaM nor inhibit ERalpha-mediated transactivation. Interestingly, melatonin does not affect the binding of coactivators to ERalpha, indicating that melatonin action is different from that of current therapeutic anti-estrogens used in breast cancer therapy. Thus, they target ERalpha at different levels, representing two independent ways to control ERalpha activity. It is, therefore, conceivably a synergistic pharmacological effect of melatonin and current anti-estrogen drugs.Journal of Biological Chemistry 10/2004; 279(37):38294-302. · 4.77 Impact Factor -
Article: The naturally occurring variant of estrogen receptor (ER) ERDeltaE7 suppresses estrogen-dependent transcriptional activation by both wild-type ERalpha and ERbeta.
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ABSTRACT: We have isolated and functionally characterized the exon 7-skipped variant (ERDeltaE7) of estrogen receptor (ER)alpha, which has emerged as the predominant variant expressed in multiple normal and tumoral tissues. However, to date no function has been established for this variant in mammalian cells. ERDeltaE7 exhibits a negligible ability to bind ligands, insensitivity to allosteric modulation by estrogen and antiestrogens, and loss of estrogen-dependent interaction with p160 coactivators such as SRC-1 and AIB1. ERDeltaE7 is able to form heterodimers with both ERalpha and ERbeta in a ligand-independent manner. Transient expression experiments in HeLa cells show that increasing amounts of ERDeltaE7 result in a progressive inhibition of the estrogen-dependent transcriptional activation by both wild-type ERalpha and ERbeta on estrogen response element-driven promoters. The inhibitory effect of ERDeltaE7 is due to the inhibition of binding of wild-type receptors to their responsive elements. Surprisingly, the activation function (AF)-1-dependent transactivation triggered by epithelial growth factor and phorbol-12-myristate-13-acetate is also abolished in ERDeltaE7 despite AF1 integrity, suggesting a cross-talk between AF1 and AF2 regions of the receptor. These results indicate that the naturally occurring variant ERDeltaE7 is a dominant negative receptor that, when expressed at high levels relative to wild-type ERs, might have profound effects on several estrogen-dependent functions.Endocrinology 08/2003; 144(7):2967-76. · 4.46 Impact Factor -
Article: Calmodulin is a selective modulator of estrogen receptors.
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ABSTRACT: In the search for differences between ERalpha and ERbeta, we analyzed the interaction of both receptors with calmodulin (CaM) and demonstrated that ERalpha but not ERbeta directly interacts with CaM. Using transiently transfected HeLa cells, we examined the effect of the CaM antagonist N-(6-aminohexyl)-5-chloro-naphthalene sulfonilamide hydrochloride (W7) on the transactivation properties of ERalpha and ERbeta in promoters containing either estrogen response elements or activator protein 1 elements. Transactivation by ERalpha was dose-dependently inhibited by W7, whereas that of ERbeta was not inhibited or even activated at low W7 concentrations. In agreement with these results, transactivation of an estrogen response element containing promoter in MCF-7 cells (which express a high ERalpha/ERbeta ratio) was also inhibited by W7. In contrast, transactivation in T47D cells (which express a low ERalpha/ERbeta ratio) was not affected by this CaM antagonist. The sensitivity of MCF-7 cells to W7 was abolished when cells were transfected with increasing amounts of ERbeta, indicating that the sensitivity to CaM antagonists of estrogen-responsive tissues correlates with a high ERalpha/ERbeta ratio. Finally, substitution of lysine residues 302 and 303 of ERalpha for glycine rendered a mutant ERalpha unable to interact with CaM whose transactivation activity became insensitive to W7. Our results indicate that CaM antagonists are selective modulators of ER able to inhibit ERalpha-mediated activity, whereas ERbeta actions were not affected or even potentiated by W7.Molecular Endocrinology 06/2002; 16(5):947-60. · 4.54 Impact Factor -
Article: [Annexin A2 expression in head and neck squamous cell carcinoma].
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ABSTRACT: Over-expression of annexin A2 (ANXA2) has been reported in various cancers. However, no data are available on the expression of this protein in head and neck squamous cell carcinomas (HNSCC). The objective of this preliminary study is to investigate the expression of ANXA2 in these carcinomas. ANXA2 expression was analyzed by immunohistochemistry in paraffin-embedded sections from 9 patients with premalignant lesions and 21 patients with HNSCC. All dysplastic tissues showed significantly reduced ANXA2 expression compared to normal tissue. In contrast, ANXA2 expression was observed in all but one of the tumours studied. There was a significant correlation of lower ANXA2 expression with a poorer histological differentiation, larger tumours, and nodal metastases. Our data show for the first time that ANXA2 is expressed in head and neck squamous cell carcinomas and that its expression seems to be related with the degree of differentiation status of these tumours.Acta Otorrinolaringológica Española 58(6):257-62.
Top co-authors
Top Journals
Institutions
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2010–2012
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Hospital Universitario Central de Asturias
Oviedo, Asturias, Spain
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2002–2012
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Universidad de Oviedo
- Departamento de Bioquímica y Biología Molecular
Oviedo, Asturias, Spain
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2006
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Imperial College London
- Institute of Reproductive and Developmental Biology
London, ENG, United Kingdom
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