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Melguizo C.,Institute of Biopathology and Regenerative Medicine IBIMER | Prados J.,Institute of Biopathology and Regenerative Medicine IBIMER | Prados J.,University of Granada | Luque R.,Service of Medical Oncology | And 6 more authors.
Cancer Chemotherapy and Pharmacology | Year: 2013

Purpose: Multidrug resistance is one of the major obstacles to the successful treatment of non-small cell lung cancer (NSCLC). An ability to identify molecular markers of drug resistance in peripheral blood cells in order to better target treatment would therefore be extremely useful in selecting therapy protocols for patients. The aim of the present study was to evaluate whether expression of resistance genes (MDR1, MRP3 and LRP) can predict clinical outcome in NSCLC patients treated with paclitaxel and carboplatin. Methods: Peripheral blood samples were obtained from lung cancer patients before and after chemotherapy and expression of the resistance gene in polymononuclear cells was detected by real-time reverse-transcription polymerase chain reaction. The results were correlated with treatment response and overall survival, which was calculated according to the Kaplan-Meier method. Results: MDR1 expression levels in PMNs rose rapidly within 24 h post-administration of paclitaxel and carboplatin, whereas MRP and LRP expression levels remained unchanged. However, no significant correlation was observed between MDR1 expression and the patients' survival or treatment response. Conclusions: Modulation of MDR1 gene expression in PMNs after lung cancer treatment with paclitaxel and carboplatin cannot be used as a prognosis marker in these patients. © 2012 Springer-Verlag Berlin Heidelberg.

Rama A.R.,University of Jaen | Rama A.R.,Institute of Biopathology and Regenerative Medicine IBIMER | Hernandez R.,Institute of Biopathology and Regenerative Medicine IBIMER | Hernandez R.,University of Granada | And 9 more authors.
International Journal of Molecular Sciences | Year: 2015

Colorectal cancer is one of the most prevalent cancers in the world. Patients in advanced stages often develop metastases that require chemotherapy and usually show a poor response, have a low survival rate and develop considerable toxicity with adverse symptoms. Gene therapy may act as an adjuvant therapy in attempts to destroy the tumor without affecting normal host tissue. The bacteriophage E gene has demonstrated significant antitumor activity in several cancers, but without any tumor-specific activity. The use of tumor-specific promoters may help to direct the expression of therapeutic genes so they act against specific cancer cells. We used the carcinoembryonic antigen promoter (CEA) to direct E gene expression (pCEA-E) towards colon cancer cells. pCEA-E induced a high cell growth inhibition of human HTC-116 colon adenocarcinoma and mouse MC-38 colon cancer cells in comparison to normal human CCD18co colon cells, which have practically undetectable levels of CEA. In addition, in vivo analyses of mice bearing tumors induced using MC-38 cells showed a significant decrease in tumor volume after pCEA-E treatment and a low level of Ki-67 in relation to untreated tumors. These results suggest that the CEA promoter is an excellent candidate for directing E gene expression specifically toward colon cancer cells. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

Cabeza L.,Institute of Biopathology and Regenerative Medicine IBIMER | Ortiz R.,Institute of Biopathology and Regenerative Medicine IBIMER | Ortiz R.,University of Jaen | Arias J.L.,University of Granada | And 8 more authors.
International Journal of Nanomedicine | Year: 2015

The use of doxorubicin (DOX), one of the most effective antitumor molecules in the treatment of metastatic breast cancer, is limited by its low tumor selectivity and its severe side effects. Colloidal carriers based on biodegradable poly(butylcyanoacrylate) nanoparticles (PBCA NPs) may enhance DOX antitumor activity against breast cancer cells, thus allowing a reduction of the effective dose required for antitumor activity and consequently the level of associated toxicity. DOX loading onto PBCA NPs was investigated in this work via both drug entrapment and surface adsorption. Cytotoxicity assays with DOX-loaded NPs were performed in vitro using breast tumor cell lines (MCF-7 human and E0771 mouse cancer cells), and in vivo evaluating antitumor activity in immunocompetent C57BL/6 mice. The entrapment method yielded greater drug loading values and a controlled drug release profile. Neither in vitro nor in vivo cytotoxicity was observed for blank NPs. The 50% inhibitory concentration (IC50) of DOX-loaded PBCA NPs was significantly lower for MCF-7 and E0771 cancer cells (4 and 15 times, respectively) compared with free DOX. Furthermore, DOX-loaded PBCA NPs produced a tumor growth inhibition that was 40% greater than that observed with free DOX, thus reducing DOX toxicity during treatment. These results suggest that DOX-loaded PBCA NPs have great potential for improving the efficacy of DOX therapy against advanced breast cancers. © 2015 Cabeza et al.

Melguizo C.,Institute of Biopathology and Regenerative Medicine IBIMER | Melguizo C.,University of Granada | Prados J.,Institute of Biopathology and Regenerative Medicine IBIMER | Prados J.,University of Granada | And 14 more authors.
Journal of Translational Medicine | Year: 2012

Background: The CD133 antigen is a marker of radio- and chemo-resistant stem cell populations in glioblastoma (GBM). The O6-methylguanine DNA methyltransferase (MGMT) enzyme is related with temozolomide (TMZ) resistance. Our propose is to analyze the prognostic significance of the CD133 antigen and promoter methylation and protein expression of MGMT in a homogenous group of GBM patients uniformly treated with radiotherapy and TMZ. The possible connection between these GBM markers was also investigated.Methods: Seventy-eight patients with GBM treated with radiotherapy combined with concomitant and adjuvant TMZ were analyzed for MGMT and CD133. MGMT gene promoter methylation was determined by methylation-specific polymerase chain reaction after bisulfite treatment. MGMT and CD133 expression was assessed immunohistochemically using an automatic quantification system. Overall and progression-free survival was calculated according to the Kaplan-Meier method.Results: The MGMT gene promoter was found to be methylated in 34 patients (44.7%) and unmethylated in 42 patients (55.3%). A significant correlation was observed between MGMT promoter methylation and patients' survival. Among the unmethylated tumors, 52.4% showed low expression of MGMT and 47.6% showed high-expression. Among methylated tumors, 58.8% showed low-expression of MGMT and 41.2% showed high-expression. No correlation was found between MGMT promoter methylation and MGMT expression, or MGMT expression and survival. In contrast with recent results, CD133 expression was not a predictive marker in GBM patients. Analyses of possible correlation between CD133 expression and MGMT protein expression or MGMT promoter methylation were negative.Conclusions: Our results support the hypothesis that MGMT promoter methylation status but not MGMT expression may be a predictive biomarker in the treatment of patients with GBM. In addition, CD133 should not be used for prognostic evaluation of these patients. Future studies will be necessary to determine its clinical utility. © 2012 Melguizo et al.; licensee BioMed Central Ltd.

Perazzoli G.,Institute of Biopathology and Regenerative Medicine IBIMER | Prados J.,Institute of Biopathology and Regenerative Medicine IBIMER | Prados J.,University of Granada | Ortiz R.,University of Jaen | And 6 more authors.
PLoS ONE | Year: 2015

Background: The use of temozolomide (TMZ) has improved the prognosis for glioblastoma multiforme patients. However, TMZ resistance may be one of the main reasons why treatment fails. Although this resistance has frequently been linked to the expression of O6-methylguanine-DNA methyltransferase (MGMT) it seems that this enzyme is not the only molecular mechanism that may account for the appearance of drug resistance in glioblastoma multiforme patients as the mismatch repair (MMR) complex, P-glycoprotein, and/or the presence of cancer stem cells may also be implicated. Methods: Four nervous system tumor cell lines were used to analyze the modulation of MGMT expression and MGMT promoter methylation by TMZ treatment. Furthermore, 5-aza-2'-deoxycytidine was used to demethylate the MGMT promoter and O(6)-benzylguanine to block GMT activity. In addition, MMR complex and P-glycoprotein expression were studied before and after TMZ exposure and correlated with MGMT expression. Finally, the effect of TMZ exposure on CD133 expression was analyzed. Results: Our results showed two clearly differentiated groups of tumor cells characterized by low (A172 and LN229) and high (SF268 and SK-N-SH) basal MGMT expression. Interestingly, cell lines with no MGMT expression and low TMZ IC50 showed a high MMR complex expression, whereas cell lines with high MGMT expression and high TMZ IC50 did not express the MMR complex. In addition, modulation of MGMT expression in A172 and LN229 cell lines was accompanied by a significant increase in the TMZ IC50, whereas no differences were observed in SF268 and SK-N-SH cell lines. In contrast, P-glycoprotein and CD133 was found to be unrelated to TMZ resistance in these cell lines. Conclusions: These results may be relevant in understanding the phenomenon of TMZ resistance, especially in glioblastoma multiforme patients laking MGMT expression, and may also aid in the design of new therapeutic strategies to improve the efficacy of TMZ in glioblastoma multiforme patients. © 2015 Perazzoli et al.

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