Carlos Palmeira

Universidade Fernando Pessoa, Oporto, Porto, Portugal

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Publications (26)58.75 Total impact


  • No preview · Article · Jan 2015
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    ABSTRACT: Gemcitabine and cisplatin regimen is an approach currently used in urinary bladder cancer treatment. However, side effects’ arising from its administration is a hard concern. In this study, we evaluated different schedules of gemcitabine and cisplatin to determine the efficacy of this combination together with two mammalian targets of rapamycin (mTOR) inhibitors: temsirolimus and everolimus. The 5637, HT1376 and T24 urinary bladder cancer cell lines were exposed to gemcitabine (72 hours), cisplatin (48 hours), temsirolimus (72 hours) and everolimus (72 hours), in isolation, or in combined schedules (gemcitabine, cisplatin and temsirolimus, or gemcitabine, cisplatin and everolimus). The levels of phosphorylated p70S6 K and 4E-BP1 after treatment with temsirolimus and everolimus were investigated by immunoblotting. The antiproliferative activity, cell cycle distribution, autophagy and apoptosis were analyzed by the MTT assay and immunocytochemistry, flow cytometry, acridine orange staining and M30 CytoDEATH antibody. No significant differences in the expression of P-4E-BP1 and P-p70S6 K after temsirolimus and everolimus exposure were found in the HT1376 and T24 cell line. A statistically significant decrease of phosphorylated 4E-BP1 form was detected in the 5637 cell line (P < 0.05) after everolimus exposure. Temsirolimus and everolimus conjugated with gemcitabine and cisplatin decreased the cell proliferation in all three cell lines. This pattern of response was similar to the other parameters analyzed (reduced Ki-67 expression, increased autophagy and apoptosis). Also, in the combined regimen, an enhanced cell cycle arrest in the G0/G1 phase in the 5637 cell line and in the early S-phase in the HT1376 and T24 cell lines were observed. The muscle invasive HT1376 and T24 cell lines were the most sensitive to both combinations. The combination of gemcitabine, cisplatin and temsirolimus or everolimus yields an enhanced cytotoxicity efficacy, namely in the muscle invasive urinary bladder cancer cell lines. Although further studies are necessary to complement this data, the present results opening new perspectives in muscle invasive urinary bladder cancer treatment.
    No preview · Article · Jul 2014 · Biomedicine and Aging Pathology
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    ABSTRACT: The aim of this paper is to analyse sunitinib malate in vitro ability to enhance cisplatin cytotoxicity in T24, 5637, and HT1376 human urinary bladder-cancer cell lines. Cells were treated with cisplatin (3, 6, 13, and 18 μ M) and sunitinib malate (1, 2, 4, 6, and 20 μ M), either in isolation or combined, over the course of 72 hours. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, acridine orange, and monodansylcadaverine staining and flow cytometry were performed. The combination index (CI) was calculated based on the Chou and Talalay method. In isolation, cisplatin and sunitinib malate statistically (). Autophagy and apoptosis studies showed a greater incidence when the combined treatment was put into use. This hints at the possibility of a new combined therapeutic approach. If confirmed in vivo , this conjugation may provide a means of new perspectives in muscle-invasive urinary bladder cancer treatment.
    Full-text · Article · Nov 2013
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    ABSTRACT: Mitoxantrone (MTX) is a chemotherapeutic agent, which presents late irreversible cardiotoxicity. This work aims to highlight the mechanisms involved in the MTX-induced cardiotoxicity, namely the effects toward mitochondria using in vivo and in vitro studies. Male Wistar rats were treated with 3 cycles of 2.5 mg/kg MTX at day 0, 10, and 20. One treated group was euthanized on day 22 (MTX22) to evaluate the early MTX cardiac toxic effects, while the other was euthanized on day 48 (MTX48), to allow the evaluation of MTX late cardiac effects. Cardiac mitochondria isolated from 4 adult untreated rats were also used to evaluate in vitro the MTX (10 nM, 100 nM, and 1 μM) direct effects upon mitochondria functionality. Two rats of MTX48 died on day 35, and MTX treatment caused a reduction in relative body weight gain in both treated groups with no significant changes in water and food intake. Decreased levels of plasma total creatine kinase and CK-MB were detected in the MTX22 group, and increased plasma levels of lactate were seen in MTX48. Increased cardiac relative mass and microscopic changes were evident in both treated groups. Considering mitochondrial effects, for the first time, it was evidenced that MTX induced an increase in the complex IV and complex V activities in MTX22 group, while a decrease in the complex V activity was accompanied by the reduction in ATP content in the MTX48 rats. No alterations in mitochondria transmembrane potential were found in isolated mitochondria from MTX48 rats or in isolated mitochondria directly incubated with MTX. This study highlights the relevance of the cumulative MTX-induced in vivo mitochondriopathy to the MTX cardiotoxicity.
    Full-text · Article · Oct 2013 · Cardiovascular toxicology
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    ABSTRACT: Mitoxantrone (MTX) is an antineoplastic agent that can induce hepato- and haematotoxicity. This work aimed to investigate the occurrence of cumulative early and late MTX-induced hepatic and haematological disturbances in a model of Wistar rats. A control group and two groups treated with 3 cycles of 2.5mg/kg MTX, at day 0, 10 and 20 were formed. One of the treated groups suffered euthanasia on day 22 (MTX22) to evaluate early MTX toxic effects, while the other suffered euthanasia on day 48 (MTX48), to allow the evaluation of MTX late effects. An early immunosuppression with a drop in the IgG levels was observed, causing a slight decrease in the plasma total protein content. The early bone marrow depression was followed by signs of recovery in MTX48. The genotoxic potential of MTX was evidenced by the presence of several micronuclei in MTX22 leukocytes. Increases in plasma iron and cholesterol levels in the MTX22 rats were observed, while in both groups increases in the unconjugated bilirubin, C4 complement, and decreases in the triglycerides, glutamic pyruvate transaminase, alkaline phosphatase, and transferrin were found in plasma samples. On MTX 48, the liver histology showed more hepatotoxic signs, the hepatic levels of reduced and oxidized glutathione were increased, and ATP hepatic levels were decreased. However, the hepatic total protein levels were decreased only in the livers of MTX22 group. Results evidenced the MTX genotoxic effects, haemato- and direct hepatotoxicity. While the haematological toxicity is ameliorated with time, the same was not observed in the hepatic injury. This article is protected by copyright. All rights reserved.
    Full-text · Article · Sep 2013 · Basic & Clinical Pharmacology & Toxicology
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    ABSTRACT: To analyze the cytotoxic action of temsirolimus using 3 established human bladder cancer cell lines and to assess whether temsirolimus potentiates the anticancer activity of gemcitabine and cisplatin. Temsirolimus (500, 1,000, 2,000, and 4,000nM), in isolation, and combined with gemcitabine (100nM) and cisplatin (2.5µg/ml), was given to 5637, T24, and HT1376 bladder cancer cell lines. Cell proliferation, autophagy, early apoptosis, and cell cycle distribution were analyzed after a 72-hour period. The expression of mammalian target of rapamycin baseline, Akt, and their phosphorylated forms, before and after treatment with temsirolimus, was evaluated by immunoblotting. Temsirolimus slightly decreased the bladder cancer cell proliferation in all 3 cell lines. No significant differences in the expression of mammalian target of rapamycin, Akt, and their phosphorylated forms because of temsirolimus exposure were found in the 3 cell lines. As part of a combined regime along with gemcitabine, and especially with cisplatin, there was a more pronounced antiproliferative effect. This pattern of response was similar to the other parameters analyzed (increased autophagy and apoptosis). Also, in the combined regime, an enhanced cell cycle arrest in the G0/G1 phase was observed. The non-muscle invasive 5637 bladder cancer cell line was most sensitive to both combinations. Temsirolimus makes a moderate contribution in terms of cell proliferation, apoptosis, and autophagy. However, it does potentiate the activity of gemcitabine and particularly cisplatin. Therefore, cisplatin- or gemcitabine-based chemotherapy regimen used in combination with temsirolimus to treat bladder cancer represents a novel and valuable treatment option, which should be tested for future studies in urinary bladder xenograft models.
    No preview · Article · Sep 2013 · Urologic Oncology
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    Full-text · Article · Aug 2013 · Toxicology Letters
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    ABSTRACT: Background: Current therapeutic strategies for advanced prostate cancer (PCa) are largely ineffective. Because aberrant DNA methylation associated with inappropriate gene-silencing is a common feature of PCa, DNA methylation inhibitors might constitute an alternative therapy. In this study we aimed to evaluate the anti-cancer properties of RG108, a novel non-nucleoside inhibitor of DNA methyltransferases (DNMT), in PCa cell lines. Methods: The anti-tumoral impact of RG108 in LNCaP, 22Rv1, DU145 and PC-3 cell lines was assessed through standard cell viability, apoptosis and cell cycle assays. Likewise, DNMT activity, DNMT1 expression and global levels of DNA methylation were evaluated in the same cell lines. The effectiveness of DNA demethylation was further assessed through the determination of promoter methylation and transcript levels of GSTP1, APC and RAR-β2, by quantitative methylation-specific PCR and RT-PCR, respectively. Results: RG108 led to a significant dose and time dependent growth inhibition and apoptosis induction in LNCaP, 22Rv1 and DU145. LNCaP and 22Rv1 also displayed decreased DNMT activity, DNMT1 expression and global DNA methylation. Interestingly, chronic treatment with RG108 significantly decreased GSTP1, APC and RAR-β2 promoter hypermethylation levels, although mRNA reexpression was only attained for GSTP1 and APC. Conclusions: RG108 is an effective tumor growth suppressor in most PCa cell lines tested. This effect is likely mediated by reversion of aberrant DNA methylation affecting cancer related-genes epigenetically silenced in PCa. However, additional mechanism might underlie the anti-tumor effects of RG108. In vivo studies are now mandatory to confirm these promising results and evaluate the potential of this compound for PCa therapy.
    Full-text · Article · Jul 2013 · Current pharmaceutical design
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    ABSTRACT: Prostate cancer (PCa) is one of the most incident malignancies worldwide. Although efficient therapy is available for early-stage PCa, treatment of advanced disease is mainly ineffective and remains a clinical challenge. microRNA (miRNA) dysregulation is associated with PCa development and progression. In fact, several studies have reported a widespread downregulation of miRNAs in PCa, which highlights the importance of studying compounds capable of restoring the global miRNA expression. The main aim of this study was to define the usefulness of enoxacin as an anti-tumoral agent in PCa, due to its ability to induce miRNA biogenesis in a TRBP-mediated manner. Using a panel of five PCa cell lines, we observed that all of them were wild type for the TARBP2 gene and expressed TRBP protein. Furthermore, primary prostate carcinomas displayed normal levels of TRBP protein. Remarkably, enoxacin was able to decrease cell viability, induce apoptosis, cause cell cycle arrest, and inhibit the invasiveness of cell lines. Enoxacin was also effective in restoring the global expression of miRNAs. This study is the first to show that PCa cells are highly responsive to the anti-tumoral effects of enoxacin. Therefore, enoxacin constitutes a promising therapeutic agent for PCa.
    Full-text · Article · Apr 2013 · Epigenetics: official journal of the DNA Methylation Society
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    ABSTRACT: Cisplatin (CDDP)-based chemotherapy is a commonly treatment for advanced urothelial carcinoma. However, episodes of cisplatin resistance have been referenced. Recently it has been reported that everolimus (RAD001) could have an important role to play in bladder-cancer treatment and that mTOR inhibitors may restore chemosensitivity in resistant tumours. The aim of this study was to assess RAD001 in vitro ability to enhance CDDP cytotoxicity in three human bladder-cancer cell lines. Over the course of 72h, the cells were exposed to different concentrations of CDDP and RAD001, isolated or combined. Treatment with CDDP statistically (P<0.05) decreased cell proliferation in cell lines in a dose-dependent manner. The anti-proliferative activity of CDDP used in combination with RAD001 was statistically significant (P<0.05) in the cell lines at all concentrations tested. RAD001 had a therapeutic effect when used in combination with CDDP and could therefore be a useful anti-cancer drug combination for patients with bladder cancer.
    No preview · Article · Mar 2013 · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
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    ABSTRACT: To assess the efficacy of meloxicam, a non-steroidal anti-inflammatory drug (NSAID), on three human urinary bladder-cancer cell lines (HT1376, T24 and 5637) and on mice urinary bladder cancer chemically induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). The in vitro effects of meloxicam were assessed by optical microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method, flow cytometry and comet assay. In vivo, Hsd:ICR male mice were exposed to BBN in drinking water, over the course of 12 weeks. Subsequently, animals were treated with meloxicam by intraperitoneal route, for 6 consecutively weeks. Tumour development was evaluated by haematoxylin and eosin staining. Renal and hepatic functions, interleucin-6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor (TNFα) were also evaluated. In vitro, meloxicam induced a significant (P<0.05) decrease of cell proliferation. A significant (P<0.05) cell cycle arrest on G0/G1 phase was also detected in all the cell lines, with a slight but significant increase of sub-G0/G1 fraction on T24 (P=0.006) and 5637 (P<0.001) cells. Also a significant (P<0.05) increase in DNA damage was found on meloxicam-treated cells. In vivo, the incidence of pre-neoplastic lesions induced by BBN was not affected by meloxicam treatment. However, although not statistically significant, the development of neoplastic lesions was inhibited by meloxicam treatment without significant alterations of renal or hepatic parameters. Meloxicam is effective on in vitro and in vivo models of urinary bladder cancer. These findings support that meloxicam deserves more attention on urinary bladder cancer study.
    No preview · Article · Feb 2013 · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
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    Full-text · Dataset · Dec 2012
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    ABSTRACT: The loss of CD45, the leukocyte-common antigen, has been described in rare cases of large B-cell lymphoma (LBCL) subtypes with extranodal involvement by immunohistochemical methods. Here we report a case of a patient with LBCL, with no extranodal lesions, which is CD45 negative by flow cytometry (FC) immunophenotyping. Immunophenotyping and DNA content analysis was performed by multiparametric FC on lymph node and bone marrow aspirate obtained from a 65 year old male patient. Malignant B-lymphocytes were CD5-, CD10+/++, CD11c-, CD19+, CD20+/++, CD23-, CD34-, CD38-/+, CD45-, CD79b++/+++, BCL2 overexpressed, FMC7++, IgM++/+++, TdT- with Lambda light chain restriction. This pathological cellular population showed near-diploid DNA content, with a high proliferate rate. To our knowledge, we describe the first case of a CD19+ B-cell non-Hodgkin lymphoma without expression of CD45 detected by FC, and the first case without extranodal involvement presentation. This case is reported not only because it is a rare one but also to raise awareness of FC users of its correct diagnosis. © 2012 International Clinical Cytometry Society.
    Preview · Article · Nov 2012 · Cytometry Part B Clinical Cytometry
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    ABSTRACT: The purpose of this study was to determine whether everolimus, a rapamycin derivative, might significantly enhance the cytotoxicity of gemcitabine, an antitumor drug, in two human bladder-cancer cell lines. Human bladder-cancer T24 and 5637 cells were incubated with gemcitabine and everolimus in a range of concentrations either alone or in combination for 72 h. Flow cytometry, comet assay, MTT method and optical microscopy were used to assess cell proliferation, cell cycle, DNA damage, and morphological alterations. Gemcitabine exerted an inhibitory effect on T24 and 5637 cell proliferation, in a concentration-dependent manner. Everolimus significantly reduced proliferation of 5637 bladder cancer cells (IC₃₀) at 1 μM), whereas T24 demonstrated marked resistance to everolimus treatment. A significant antiproliferative effect was obtained combining gemcitabine (100 nM) with everolimus (0.05-2 μM) with an arrest of cell cycle at S phase. Furthermore, an increase in frequency of DNA damage, apoptotic bodies, and apoptotic cells was observed when T24 and 5637 cancer cells were treated simultaneously with both drugs. Data show that in vitro combination produced a more potent antiproliferative effect when compared with single drugs.
    No preview · Article · Jul 2012 · Journal of Toxicology and Environmental Health Part A

  • No preview · Article · Jun 2012 · Toxicology Letters
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    ABSTRACT: OBJECTIVE: To evaluate the influence of Everolimus (RAD001) on chemically induced urothelial lesions in mice and its influence on in vitro human bladder cancer cell lines. METHODS: ICR male mice were given N-butyl-N-(4-hydroxybutyl) nitrosamine in drinking water for a period of 12 weeks. Subsequently, RAD001 was administered via oral gavage, for 6 weeks. At the end of the experiment, all the animals were sacrificed and tumor development was determined by means of histopathologic evaluation; mammalian target of rapamycin (mTOR) expressivity was evaluated by immunohistochemistry. Three human bladder cancer cell lines (T24, HT1376, and 5637) were treated using a range of RAD001 concentrations. MTT assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and flow cytometry were used to assess cell proliferation, apoptosis index, and cell cycle analysis, respectively. Immunoblotting analysis of 3 cell line extracts using mTOR and Akt antibodies was performed in order to study the expression of Akt and mTOR proteins and their phosphorylated forms. RESULTS: The incidence of urothelial lesions in animals treated with RAD001 was similar to those animals not treated. RAD001 did not block T24 and HT1376 cell proliferation or induce apoptosis. A reduction in cell proliferation rate and therefore G(0)/G(1) phase arrest, as well as a statistically significant induction of apoptosis (P = 0.001), was only observed in the 5637 cell line. CONCLUSION: RAD001 seems not to have a significant effect on chemically induced murine bladder tumors. The effect of RAD001 on tumor proliferation and apoptosis was achieved only in superficial derived bladder cancer cell line, no effect was observed in invasive cell lines.
    No preview · Article · Dec 2011 · Urologic Oncology
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    ABSTRACT: The present study investigated the similarities between rodent and human urothelial carcinogenesis models using DNA content, p53 and Ki-67 immunoexpression as surrogate markers of bladder carcinogenesis. Following N-butyl-N-(4-hydroxybutyl)-nitrosamine exposure, 49 human cystectomy specimens of bladder cancer and 53 rat bladder specimens were studied. All of the tumours and adjacent mucosa present in each specimen were evaluated. High similarities were observed between the rodent urothelium carcinogenesis process and the corresponding process in humans, in regards to the histopathological features and biological alteration profile: DNA aneuploidy, p53 overexpression and high proliferative index measured by Ki-67 immunoexpression. Despite these similarities, a higher frequency of alterations was observed in earlier stages in the rat chemical-induced carcinogenesis, namely in 5c aneuploid cells, p53 overexpression and higher Ki-67 labelling index. These results confirm that this experimental animal model is a suitable and reproducible model of bladder carcinogenesis, particularly in regards to high-risk non-invasive and invasive urothelial carcinomas. These features mandate its use in the identification of new molecular targets and evaluation of tumour response to new cytotoxic drugs or drug combinations in bladder cancer therapeutic intervention.
    Full-text · Article · Mar 2010 · Oncology letters
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    ABSTRACT: Feline mammary carcinomas (FMC) are highly infiltrative tumours which show a strong tendency for local recurrence and metastasis. Histological type assessment of these tumours is not sufficiently discriminatory in predicting prognosis and in this study the prognostic significance of the Elston and Ellis method of histological grading was evaluated. Ninety-two feline mammary carcinomas from 84 cats were graded and 64 queens were included in a follow-up study. Grade was significantly related to tumour size (P=0.006), clinical stage (P=0.005), lymphovascular invasion (P<0.0001), mitotic index (P<0.0001), Ki67 index (P=0.001), overall survival (P=0.0001) and disease-free survival (P<0.0001). Cox regression analysis identified grade as an independent prognostic factor. Multivariable analysis also showed regional lymph node metastasis and lymphovascular emboli as independent prognostic factors related to overall survival and to disease-free-survival, respectively. The study demonstrated that histological grading can be used as a prognostic factor to evaluate the biological behaviour of FMC.
    Full-text · Article · Nov 2009 · The Veterinary Journal
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    ABSTRACT: To investigate whether carcinoma in situ (CIS) lesion could be considered a surrogate marker of urothelium genetic instability and field carcinogenesis or not, we evaluated DNA content, p53 overexpression, and proliferative index (Ki-67 expression) in primary tumor, in tumor-adjacent mucosa, and distant urothelial mucosa with and without presence of CIS. A retrospective study in radical cystectomy specimens from 49 patients was carried out. All the lesions present in each cystectomy specimen were studied, including the tumor area and the adjacent mucosa (AM). Whenever possible, the distant mucosa (DM) was also studied. When CIS was detected, this lesion and the surrounding normal mucosa were also studied. The 49 tumor areas included high grade papillary urothelial carcinoma (HGP) in 19 cases (38.8%) and invasive urothelial cell carcinomas in 30 cases (61.2%). The nuclear DNA content of cancer cells was evaluated using image cytometry allowing the determination of the DNA ploidy and 5cER parameters. The p53 and Ki-67 immunoexpression was evaluated by immunohistochemistry. CIS lesions were observed in the AM and DM of both tumor groups: 15.8% and 15.4% in AM and DM, for each one of them, in HGP group and 26.7% and 22.2% in AM and DM, for each one of them, in invasive tumors group. In CIS lesion aneuploid DNA content, p53 overexpression and high proliferative labeling index were observed. The so-called normal mucosa (AM and DM) with and without focus of CIS lesions were compared for genetic instability and molecular alterations profile. Statistical differences were observed between the normal mucosa with and without CIS: the so-called normal mucosa areas with focus of CIS revealed significantly higher frequencies of DNA content alterations, p53 overexpression, and higher proliferative index. These differences were significantly different in the invasive UCC group, but this profile it is also present in HPG group. This study points out that CIS is a marker of genetic instability of the urothelium mucosa. The CIS surrounding morphologically normal urothelium showed a high frequency of abnormal DNA content, with high percentage of clear aneuploid cells (high 5cER), p53 mutated protein expression, and a proliferative status underlying a field carcinogenesis. These alterations in normal mucosa were not found when CIS was not present.
    No preview · Article · Oct 2009 · Urologic Oncology
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    ABSTRACT: Feline mammary carcinomas are known for their unfavourable prognosis due to a strong tendency to local recurrence and metastasis. We studied 73 spontaneous primary mammary carcinomas and identified eight cases presenting a biphasic nature, with neoplastic epithelial and myoepithelial cells (complex carcinoma). These cases presented histopathologic features associated with a better prognosis; they were also associated with higher overall survival and disease-free survival rates compared to other common invasive mammary carcinomas of non-specified type. Complex carcinoma appears to be a low-grade malignancy.
    No preview · Article · Jul 2008 · Research in Veterinary Science

Publication Stats

303 Citations
58.75 Total Impact Points

Institutions

  • 2007-2014
    • Universidade Fernando Pessoa
      Oporto, Porto, Portugal
  • 2013
    • University of Porto
      Oporto, Porto, Portugal
    • University of Coimbra
      • Department of Life Sciences
      Coímbra, Coimbra, Portugal
  • 2003-2013
    • Instituto Português de Oncologia
      • • Department of Hematology
      • • Molecular Oncology Group
      Oporto, Porto, Portugal