[Show abstract][Hide abstract] ABSTRACT: Vinflunine (VFL) is a microtubule-targeting drug that suppresses microtubule dynamics, showing anti-metastatic properties both in vitro and in living cancer cells. An increasing body of evidence underlines the influence of the microtubules dynamics on the cadherin-dependent cell-cell adhesions. E-cadherin is a marker of epithelial-to-mesenchymal transition (EMT) and a tumour suppressor; its reduced levels in carcinoma are associated with poor prognosis. In this report, we investigate the role of VFL on cell-cell adhesions in bladder epithelial tumour cells.
BMC Cancer 07/2014; 14(1):507. · 3.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Docetaxel is the standard first-line chemotherapy for men with metastatic castration-resistant prostate cancer. Until recently, there was no standard therapy after failure of docetaxel treatment. Cabazitaxel has been shown to improve overall survival in this setting. As a result, the treatment paradigm for mCRPC is changing rapidly. The improved survival shown with cabazitaxel provides an important new opportunity to treat men with mCRPC after docetaxel treatment. Despite the toxicity recorded in the pivotal study, subsequent trials have shown that cabazitaxel is a safe drug. Patient selection and the optimal interval between prior docetaxel treatment and cabazitaxel remain the critical issues. According to a subanalysis of the various studies discussed in this review, there is a patient profile that will probably benefit from use of cabazitaxel after docetaxel failure. Cabazitaxel represents a new treatment option for patients with prostate cancer.
[Show abstract][Hide abstract] ABSTRACT: Epithelial-to-mesenchymal transition (EMT), one of the crucial steps for carcinoma cells to acquire invasive capacity, results from the disruption of cell-cell contacts and the acquisition of a motile mesenchymal phenotype. Although the transcriptional events controlling EMT have been extensively studied, in recent years, several posttranscriptional mechanisms have emerged as critical in the regulation of EMT during tumor progression. In this review, we highlight the regulation of posttranscriptional events in EMT by RNA-binding proteins (RBPs). RBPs are responsible for controlling pre-mRNA splicing, capping, and polyadenylation, as well as mRNA export, turnover, localization, and translation. We discuss the most relevant aspects of RBPs controlling the metabolism of EMT-related mRNAs, and describe the implication of novel posttranscriptional mechanisms regulating EMT in response to different signaling pathways. Novel insight into posttranscriptional regulation of EMT by RBPs is uncovering new therapeutic targets in cancer invasion and metastasis.
Cellular and Molecular Life Sciences CMLS 05/2013; · 5.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gene expression is potently regulated through the action of microRNAs (miRNAs). Here, we present evidence of a miRNA regulating Hakai protein. Hakai was discovered as an E3 ubiquitin-ligase that mediates the posttranslational downregulation of E-cadherin, a major component of adherens junctions in epithelial cells and a potent tumour suppressor. Recent data have provided evidence that Hakai affects cell proliferation in an E-cadherin-independent manner, thus revealing a role for Hakai in the early stages of tumour progression. Furthermore, Hakai is highly up-regulated in human colon adenocarcinomas compared to normal tissues. However, the molecular mechanisms that regulate Hakai abundance are unknown. We identified two putative sites of miR-203 interaction on the Hakai mRNA, in its 3'-untranslated region (UTR). In several human carcinoma cell lines tested, overexpression of a miR-203 precursor (Pre-miR-203) reduced Hakai abundance, while inhibiting miR-203 by using an antisense RNA (Anti-miR-203) elevated Hakai levels. The repressive influence of miR-203 on the Hakai 3'-UTR was confirmed using heterologous reporter constructs. In keeping with Hakai's proliferative influence, Anti-miR-203 significantly increased cell number and BrdU incorporation, while Pre-miR-203 reduced these parameters. Importantly, the growth-promoting effects of anti-miR-203 required the presence of Hakai, because downregulation of Hakai by siRNA suppressed its proliferative action. Finally, in situ hybridization showed that miR-203 expression is attenuated in colon tumour tissues compared to normal colon tissues, suggesting that miR-203 could be a potential new prognostic marker and therapeutic target to explore in colon cancer. In conclusion, our findings reveal, for the first time, a post-transcriptional regulator of Hakai expression. Furthermore, by lowering Hakai abundance, miR-203 also reduces Hakai-regulated-cell division.
PLoS ONE 12/2012; 7(12):e52568. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the last several years, researchers have exhibited an intense interest in the evolutionarily conserved signaling pathways that have crucial roles during embryonic development. Interestingly, the malfunctioning of these signaling pathways leads to several human diseases, including cancer. The chemical and biophysical events that occur during cellular signaling, as well as the number of interactions within a signaling pathway, make these systems complex to study. In silico resources are tools used to aid the understanding of cellular signaling pathways. Systems approaches have provided a deeper knowledge of diverse biochemical processes, including individual metabolic pathways, signaling networks and genome-scale metabolic networks. In the future, these tools will be enormously valuable, if they continue to be developed in parallel with growing biological knowledge. In this study, an overview of the bioinformatics resources that are currently available for the analysis of biological networks is provided.
International Journal of Molecular Sciences 12/2012; 13(6):6561-81. · 2.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Historically, cell-signaling pathways have been studied as the compilation of isolated elements into a unique cascade that transmits extracellular stimuli to the tumor cell nucleus. Today, growing evidence supports the fact that intracellular drivers of tumor progression do not flow in a single linear pathway, but disseminate into multiple intracellular pathways. An improved understanding of the complexity of cancer depends on the elucidation of the underlying regulatory networks at the cellular and intercellular levels and in their temporal dimension. The high complexity of the intracellular cascades causes the complete inhibition of the growth of one tumor cell to be very unlikely, except in cases in which the so-called “oncogene addiction” is known to be a clear trigger for tumor catastrophe, such as in the case of gastrointestinal stromal tumors or chronic myeloid leukemia. In other words, the separation and isolation of the driver from the passengers is required to improve accuracy in cancer treatment. This review will summarize the signaling pathway crossroads that govern renal cell carcinoma proliferation and the emerging understanding of how these pathways facilitate tumor escape. We outline the available evidence supporting the putative links between different signaling pathways and how they may influence tumor proliferation, differentiation, apoptosis, angiogenesis, metabolism and invasiveness. The conclusion is that tumor cells may generate their own crossroads/crosstalk among signaling pathways, thereby reducing their dependence on stimulation of their physiologic pathways.
International Journal of Molecular Sciences 12/2012; 13(10):12710-33. · 2.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Many studies have demonstrated genetic and environmental factors that lead to renal cell carcinoma (RCC) and that occur during a protracted period of tumourigenesis. It appears suitable to identify and characterise potential molecular markers that appear during tumourigenesis and that might provide rapid and effective possibilities for the early detection of RCC. EGFR activation induces cell cycle progression, inhibition of apoptosis and angiogenesis, promotion of invasion/metastasis, and other tumour promoting activities. Over-expression of EGFR is thought to play an important role in tumour initiation and progression of RCC because up-regulation of EGFR has been associated with high grade cancers and a worse prognosis. METHODS: Characterisation of the protein profile interacting with EGFR was performed using the following: an immunohistochemical (IHC) study of EGFR, a comprehensive computational study of EGFR protein-protein interactions, an analysis correlating the expression levels of EGFR with other significant markers in the tumourigenicity of RCC, and finally, an analysis of the utility of EGFR for prognosis in a cohort of patients with renal cell carcinoma. RESULTS: The cases that showed a higher level of this protein fell within the clear cell histological subtype (p = 0.001). The EGFR significance statistic was found with respect to a worse prognosis. In vivo significant correlations were found with PDGFR-beta, Flk-1, Hif1-alpha, proteins related to differentiation (such as DLL3 and DLL4 ligands), and certain metabolic proteins such as Glut5. In silico significant associations gave us a panel of 32 EGFR-interacting proteins (EIP) using the APID and STRING databases. CONCLUSIONS: This work summarises the multifaceted role of EGFR in the pathology of RCC, and it identifies EIPs that could help to provide mechanistic explanations for the different behaviours observed in tumours.
[Show abstract][Hide abstract] ABSTRACT: Kidney tumours are frequently characterised by hypoxic conditions due to a local imbalance between oxygen (O(2)) supply and consumption. Hif1-α regulates angiogenesis, tumour growth, tumour progression, metastatic spread, and glucose metabolism by acting as a transcription factor for relevant genes. Here, we describe an immunohistochemical study of Hif1-α, a comprehensive computational study of Hif1-α interacting proteins (HIPs), an analysis correlating expression levels of Hif1-α with upstream and downstream proteins, and an analysis of the utility of Hif1-α for prognosis in a cohort of patients with renal cell carcinoma.
The patient cohort included 80 patients. For immunohistochemistry evaluation, tissue microarrays were constructed. The IntAct, MINT, and BOND databases were used for the HIP approach. The Kruskal-Wallis test was used for comparing protein expression with pathology measurements. Correlation was expressed as the Pearson coefficient.
Hif1-α expression correlates significantly with the "clear" histological subtype of renal cell carcinoma (p < 0.01). The samples with the worst prognoses related to the pathological variables analysed showed the highest levels of Hif1-α expression. Significant correlations were found with Bcl-2, CAIX, C-kit, EGFR, TGF-β, proteins of the VEGF family, proteins related to differentiation (such as Notch1 and Notch3) and certain metabolic enzymes. Bioinformatic analysis suggested 45 evidence-based HIPs and 4 complexes involving protein Hif1-α.
This work summarises the multifaceted role of Hif1-α in the pathology of renal cell carcinomas, and it identifies HIPs that could help provide mechanistic explanations for the different behaviours seen in tumours.
Clinical and Translational Oncology 08/2012; 14(9):698-708. · 1.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Quantitative Real Time PCR (qPCR) is a highly sensitive method commonly used for the detection of circulating tumor cells (CTC) in peripheral blood of patients with malignant breast tumors. The rationale for using microRNAs (miRNA) as potential therapeutic targets is explained by the fact that miRNAs overexpression in cancer cells has a pathogenic effect. miRNAs may constitute a promising new class of cancer biomarkers for CTC detection. Our primary purpose is to use this approach to identify microRNAs with diagnostic and prognostic value in peripheral blood of patients suffering from breast cancer (BC).
Material and Methods: We used different online bioinformatics tools allowing us to select a panel of microRNAs with high expression in breast tumors while low or no expression in control peripheral blood (PB) and bone marrow. The usefulness of potential up-regulated miRNAs from previous bioinformatic analysis was validated in human breast cell lines: BT549, MCF7, MDA-MB-231, PM1 and T47D; hematopoietic cell lines: JURKAT, KG1 and K562; human breast total RNA (Ambion®), and healthy blood samples (n = 19). mirVana miRNA and RiboPure Blood isolation kits (Ambion®) were used. Using qRT-PCR miRNAs tumor-related were amplified. Genex 5.0.1 (MultiD Analyses) was used as qPCR data analysis software.
Results: Among a panel of 12 microRNAs analyzed highlight 5 upregulated in breast tumors: miR-32, miR-200a, miR-200b, and the cluster miR-200c/141 fulfilled the premises of bioinformatic searches. For instance, relative expression of mir-32 and mir-141 was 1.09×103 and 1.08×103 respectively, higher in T47d cells than in control PB (n = 19).
Conclusions: These results suggest that this bioinformatic approach is an useful high-throughout method to identified BC associated miRNAs. Actually our group is actively involved in the study of selected miRNAs for their potential as markers for CTC detection in peripheral blood of BC patients and age-matched healthy control subjects. Supported by Grants PI06/1541 and PI07/0477 from Fondo de Investigaciones Sanitarias (FIS), Instituto de Salud Carlos III. Cancer research in our laboratory is supported by the ‘Fundación do CHU A Coruña’.
8th EBCC (European Breast Cancer Conference), Vienna, Austria; 03/2012
[Show abstract][Hide abstract] ABSTRACT: In order to metastasize, cancer cells must first detach from the primary tumor, migrate, invade through tissues, and attach to a second site. Hakai was discovered as an E3 ubiquitin-ligase that mediates the posttranslational downregulation of E-cadherin, a major component of adherens junctions in epithelial cells that is characterized as a potent tumor suppressor and is modulated during various processes including epithelial-mesenchymal transition. Recent data have provided evidences for novel biological functional role of Hakai during tumor progression and other diseases. Here, we will review the knowledge that has been accumulated since Hakai discovery 10 years ago and its implication in human cancer disease. We will highlight the different signaling pathways leading to the influence on Hakai and suggest its potential usefulness as therapeutic target for cancer.
CANCER AND METASTASIS REVIEW 02/2012; 31(1-2):375-86. · 9.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tyrosine kinase inhibitors (TKIs) are beneficial for the treatment of renal cell carcinoma (RCC), gastrointestinal stromal tumors (GIST), pancreatic neuroendocrine tumors (pNETs), and other tumors. The antitumor activity of sunitinib has been based on time-related parameters such as progression-free survival (PFS) and overall survival (OS). Advances in knowledge of the molecular mechanisms and oncogenic processes associated with RCC have enabled the availability of rational targets for pharmacotherapy. Although each small molecule is modeled to block the activity of selected kinase signaling enzymes, it is increasingly evident that many have nontargeted effects (on other kinases) that may cause unexpected complications. The recommended dose for sunitinib in patients with advanced RCC is a 50 mg oral daily dose, with or without food, on a 4/2 week schedule (4 weeks "on" vs. 2 weeks "off") until progression. An alternative continuous 37.5 mg/day dosing schedule has also been evaluated and appears to be well tolerated, allowing the maintenance of the dose density of sunitinib with a similar outcome. The continuous administration schedule provides a constant exposure to the drug, and may prevent potential tumor regrowth and angiogenesis recovery. Most side effects are reversible and should not result in sunitinib discontinuation. In this article, the body of evidence behind the use of sunitinib in metastatic RCC (mRCC) compared to other targeted agents that have recently come into the field is summarized, and the need for correct management of an adverse event profile in order to better optimize available treatment options is underlined.
Advances in Therapy 02/2012; 29(3):202-17. · 2.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microtubules and tubulin are major dynamic and structural cellular components that play a key role in several cell functions, including division, signalling and intracellular trafficking. Normal epithelial cells have a highly structured, rigid cytoskeletal network that is compatible with cell motility. Thus, tubulin and microtubules are compelling cellular targets for chemotherapy. In fact, among anticancer agents, those that target microtubules constitute one of the most effective classes of chemotherapeutics in cancer. The list of compounds that target either tubulin or microtubules is extensive and consists of chemically unique compounds that bind to the tubulin dimers and destabilize microtubules (Vinca alkaloids) and those that bind to the microtubule polymer and stabilize microtubules (taxanes). Tumour-induced angiogenesis, the formation of new capillaries from existing blood vessels, and epithelial-mesenchymal transition are two steps that are critical for both tumour growth and metastatic spread. Three possible mechanisms of action are described with vinflunine, the new-generation Vinca alkaloid to arrive in clinical practice are as follows: it acts against tubulin and microtubules, disrupts newly formed blood vessels and seems to be able to reduce the metastatic process as shown in preclinical studies. These findings support the hypothesis that vinflunine, by blocking microtubule functions that contribute to cell shape, polarization, migration and other processes, might be responsible not only for tumour-cytostatic but also for specific antiangiogenic or antiepithelial-mesenchymal transition effects.
[Show abstract][Hide abstract] ABSTRACT: Renal cell carcinoma is the most common type of kidney cancer. A better understanding of the critical pathways and interactions associated with alterations in renal function and renal tumour properties is required. Our final goal is to combine the knowledge provided by a regulatory network with experimental observations provided by the dataset.
In this study, a systems biology approach was used, integrating immunohistochemistry protein expression profiles and protein interaction information with the STRING and MeV bioinformatics tools. A group consisting of 80 patients with renal cell carcinoma was studied. The expression of selected markers was assessed using tissue microarray technology on immunohistochemically stained slides. The immunohistochemical data of the molecular factors studied were analysed using a parametric statistical test, Pearson's correlation coefficient test.
Bioinformatics analysis of tumour samples resulted in 2 protein networks. The first network consists of proteins involved in the angiogenesis pathway and the apoptosis suppressor, BCL2, and includes both positive and negative correlations. The second network shows a negative interaction between the p53 tumour suppressor protein and the glucose transporter type 4.
The comprehensive pathway network will help us to realise the cooperative behaviours among pathways. Regulation of metabolic pathways is an important role of p53. The pathway involving the tumour suppressor gene p53 could regulate tumour angiogenesis. Further investigation of the proteins that interact with this pathway in this type of tumour may provide new strategies for cancer therapies to specifically inhibit the molecules that play crucial roles in tumour progression.
International journal of biomedical science : IJBS. 12/2011; 7(4):273-282.
[Show abstract][Hide abstract] ABSTRACT: The dynamic regulation of cell-cell adhesions is crucial for developmental processes, including tissue formation, differentiation and motility. Adherens junctions are important components of the junctional complex between cells and are necessary for maintaining cell homeostasis and normal tissue architecture. E-cadherin is the prototype and best-characterized protein member of adherens junctions in mammalian epithelial cells. Regarded as a tumour suppressor, E-cadherin loss is associated with poor prognosis in carcinoma. The E3 ubiquitin-ligase Hakai was the first reported posttranslational regulator of the E-cadherin complex. Hakai specifically targetted E-cadherin for internalization and degradation and thereby lowered epithelial cell-cell contact. Hakai was also implicated in controlling proliferation, and promoted cancer-related gene expression by increasing the binding of RNA-binding protein PSF to RNAs encoding oncogenic proteins. We sought to investigate the possible implication of Hakai in cell-substratum adhesions and invasion in epithelial cells.
Parental MDCK cells and MDCK cells stably overexpressing Hakai were used to analyse cell-substratum adhesion and invasion capabilities. Western blot and immunofluoresecence analyses were performed to assess the roles of Paxillin, FAK and Vinculin in cell-substratum adhesion. The role of the proteasome in controlling cell-substratum adhesion was studied using two proteasome inhibitors, lactacystin and MG132. To study the molecular mechanisms controlling Paxillin expression, MDCK cells expressing E-cadherin shRNA in a tetracycline-inducible manner was employed.
Here, we present evidence that implicate Hakai in reducing cell-substratum adhesion and increasing epithelial cell invasion, two hallmark features of cancer progression and metastasis. Paxillin, an important protein component of the cell-matrix adhesion, was completely absent from focal adhesions and focal contacts in Hakai-overexpressing MDCK cells. The expression of Paxillin was found to be regulated by a proteasome-independent mechanism, possibly due to the decreased abundance of E-cadherin.
Taken together, these results suggest that Hakai may be involved in two hallmark aspects of tumour progression, the lowering cell-substratum adhesion and the enhancement of cell invasion.
[Show abstract][Hide abstract] ABSTRACT: Asthenia-fatigue syndrome (AFS) is defined as a persistent, subjective sense of tiredness related to cancer or its treatment and greatly impacts quality of life among cancer patients. All tyrosine kinase inhibitors, but especially sunitinib, may induce AFS. The reason for sunitinib-induced AFS is not yet well understood. Adverse events caused by sunitinib associated with AFS may include anemia, hypothyroidism, nausea and vomiting. However, AFS is also reported when active treatment with sunitinib is ongoing, and no other relevant adverse event can justify it. The molecular mechanisms by which sunitinib triggers AFS remain elusive. Sunitinib displays multiple off-target tyrosine-kinase interactions and competitively inhibits multiple proteins through the blockade of their ATP-binding sites. The broad spectrum of kinases inhibited may play a key role not only in terms of activity but also in terms of toxicity induced by sunitinib. This study considered different clinical observations and current metabolic and pharmacological knowledge, leading to hypotheses regarding which molecular mechanisms may be involved in sunitinib-induced AFS in cancer patients. Deeper knowledge of the molecular mode of action of sunitinib may lead to improved optimization of its clinical use.
Cancer biology & therapy 11/2011; 12(9):765-71. · 3.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Most of the archived pathological specimens in hospitals are kept as formalin-fixed paraffin-embedded tissues (FFPE) for long-term preservation. Up to now, these samples are only used for immunohistochemistry in a clinical routine as it is difficult to recover intact protein from these FFPE tissues. Here, we report a novel, short time-consuming and cost-effective method to extract full-length, non-degraded proteins from FFPE tissues. This procedure is combined with an effective and non-toxic deparaffinisation process and an extraction method based on antigen-retrieval, high concentration of SDS and high temperature. We have obtained enough intact protein to be detected by Western blotting analysis. This technique will allow utilising these stored FFPE tissues in several applications for protein analysis helping to advance the translational studies in cancer and other diseases. Abstract published in Proteomics Clin. Appl. 2011, 5, 542–570; extracted from full paper published in: Proteomics 2011, 11, 2555–2559.
[Show abstract][Hide abstract] ABSTRACT: Prostate epithelial and stromal cells develop paracrine interactions, which may be responsible for the occurrence and progression of prostate pathologies. Strikingly, stromal cells exhibit pleiotropic effects on epithelial cell growth, ranging from stimulation to inhibition. Steroid hormone receptors are considered ligand-activated transcriptional factors. Moreover, it has been suggested that the human androgen receptor can also be activated in the absence of surrounding ligands such as growth factors and cytokines. Strong evidence suggests that cytokines may play an important role in ligand-independent activation of androgen receptor in prostate cancer cells. In our view, one of the most striking finding in the prostate cancer development process is the relationship between carcinogenesis and secretion of cytokines.
Medical Oncology 08/2011; 29(3):1956-63. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Most of the archived pathological specimens in hospitals are kept as formalin-fixed paraffin-embedded tissues (FFPE) for long-term preservation. Up to now, these samples are only used for immunohistochemistry in a clinical routine as it is difficult to recover intact protein from these FFPE tissues. Here, we report a novel, short time-consuming and cost-effective method to extract full-length, non-degraded proteins from FFPE tissues. This procedure is combined with an effective and non-toxic deparaffinisation process and an extraction method based on antigen-retrieval, high concentration of SDS and high temperature. We have obtained enough intact protein to be detected by Western blotting analysis. This technique will allow utilising these stored FFPE tissues in several applications for protein analysis helping to advance the translational studies in cancer and other diseases.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to provide a methodology to make a clear distinction between malignant tumors and morphologically similar benign processes, by examining the expression of EGFR, VEGF, HIF1-α, survivin, Bcl-2 and p53 proteins. Four groups of patient samples were studied: group 1, low-grade astrocytomas (WHO grades I-II) (n=6); group 2, peripheral area of high-grade astrocytomas (WHO grades III-IV) (n=5); group 3, gliomatosis cerebri (n=11); and group 4, reactive gliosis (n=6). Tissue arrays (TAs) were designed to study apoptosis, angiogenesis and invasion-related proteins by immunohistochemistry (IHC). By means of non-parametric analysis (Mann-Whitney U test), EGFR staining was shown to be significantly lower in reactive gliosis than in the low- and high-grade astrocytomas (p=0.015 and p=0.030, respectively); Bcl-2 immunoreactivity was significantly higher in the gliomatosis cerebri samples than in the reactive processes (p=0.005); and finally, Bcl-2 presented significantly lower expression levels in reactive gliosis compared to the peripheral areas of high-grade astrocytomas (p=0.004). The results indicate that Bcl-2 and EGFR may be useful in conducting differential diagnosis between the above groups, while the expression of the remaining antibodies does not appear to aid in distinguishing between the samples analyzed. The use of TAs to identify the protein expression profiles of biological markers related to different pathways was verified, and its potential as a discriminatory technique for everyday pathology procedures was demonstrated.
Molecular Medicine Reports 05/2011; 4(3):451-7. · 1.48 Impact Factor