[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
PLoS ONE 10/2015; 10(10):e0140131. DOI:10.1371/journal.pone.0140131 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The presence of cancer stem cells (CSCs) or tumor-initiating cells can lead to cancer recurrence in a permissive cell-microenvironment interplay, promoting invasion in glioblastoma (GBM) and neuroblastoma (NB). Extracellular matrix (ECM) small leucine-rich proteoglycans (SLRPs) play multiple roles in tissue homeostasis by remodeling the extracellular matrix (ECM) components and modulating intracellular signaling pathways. Due to their pan-inhibitory properties against receptor tyrosine kinases (RTKs), SLRPs are reported to exert anticancer effects in vitro and in vivo. However, their roles seem to be tissue-specific and they are also involved in cancer cell migration and drug resistance, paving the way to complex different scenarios. The aim of this study was to determine whether the SLRPs decorin (DCN) and lumican (LUM) are recruited in cell plasticity and microenvironmental adaptation of differentiated cancer cells induced towards stem-like phenotype. Floating neurospheres were generated by applying CSC enrichment medium (neural stem cell serum-free medium, NSC SFM) to the established SF-268 and SK-N-SH cancer cell lines, cellular models of GBM and NB, respectively. In both models, the time-dependent synergistic activation of DCN and LUM was observed. The highest DCN and LUM mRNA/protein expression was detected after cell exposure to NSC SFM for 8/12 days, considering these cells as SLRP-expressing (SLRP+) CSC-like. Ultrastructural imaging showed the cellular heterogeneity of both the GBM and NB neurospheres and identified the inner living cells. Parental cell lines of both GBM and NB grew only in soft agar + NSC SFM, whereas the secondary neurospheres (originated from SLRP+ t8 CSC-like) showed lower proliferation rates than primary neurospheres. Interestingly, the SLRP+ CSC-like from the GBM and NB neurospheres were resistant to temozolomide (TMZ) at concentrations >750 μM. Our results suggest that GBM and NB CSC-like promote the activation of huge quantities of SLRP in response to CSC enrichment, simultaneously acquiring TMZ resistance, cellular heterogeneity, and a quiescent phenotype, suggesting a novel pivotal role for SLRP in drug resistance and cell plasticity of CSC-like, allowing cell survival and ECM/niche modulation potential.
PLoS ONE 08/2015; DOI:10.1371/journal.pone.0134111 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
International Journal of Molecular Sciences 06/2015; 16(6):12601-12615. DOI:10.3390/ijms160612601 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The clinical use of 5-fluorouracil, one of the drugs of choice in colon cancer therapy, is limited by a nonuniform oral absorption, a short plasma half-life, and by the development of drug resistances by malignant cells. We hypothesized that the formulation of biodegradable nanocarriers for the efficient delivery of this antitumor drug may improve its therapeutic effect against advanced or recurrent colon cancer. Hence, we have engineered two 5-fluorouracil-loaded nanoparticulate systems based on the biodegradable polymers poly(butylcyanoacrylate) and poly(ε-caprolactone). Drug incorporation to the nanosystems was accomplished by entrapment (encapsulation/dispersion) within the polymeric network during nanoparticle synthesis, i.e., by anionic polymerization of the monomer and interfacial polymer disposition, respectively. Main factors determining 5-fluorouracil incorporation within the polymeric nanomatrices were investigated. These nanocarriers were characterized by high drug entrapment efficiencies and sustained drug-release profiles. In vitro studies using human and murine colon cancer cell lines demonstrated that both types of nanocarriers significantly increased the antiproliferative effect of the encapsulated drug. In addition, both nanoformulations produced in vivo an intense tumor growth inhibition and increased the mice survival rate, being the greater tumor volume reduction obtained when using the poly(ε-caprolactone)-based formulation. These results suggest that these nanocarriers may improve the antitumor activity of 5-fluorouracil and could be used against advanced or recurrent colon cancer.
The AAPS Journal 04/2015; 17(4). DOI:10.1208/s12248-015-9761-5 · 3.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Development of the European Higher Education Area is linked to the adoption of a new educational model. Thus, in the Health Sciences, basic science knowledge must be integrated with the clinical skills that students will require in their professional activity. The Anatomy and Embryology Teaching Investigation Group at our university (UGR-N-40-UCUA) designed a specific questionnaire to analyse specific items that affect Anatomy learning. It also developed a teaching methodology for the acquisition of anatomic knowledge, integrating theory and practice, including individual and collective tasks for students and leading to future self-learning. Analyses were performed in different groups of first-year students at the School of Medicine of Granada University, School of Nursing of Almería University and School of Physiotherapy of Jaén University. It was found that application of this teaching methodology achieved an improvement in two areas considered essential by these students, i.e. a better understanding of several aspects of the study subject, and greater satisfaction with their acquisition of anatomic and embryologic knowledge.
[Show abstract][Hide abstract] ABSTRACT: The integration of the Spanish university system within the European Higher Education Area implies a change in the current educational model towards a more flexible system that establishes the equivalence of degrees and encourages greater competition among courses. In this system, students will be expected to make a greater contribution to real learning in order for it to be more useful in their future professional activity. These changes will involve new student-teacher relationships, new methodologies, new teaching strategies and different evaluation systems. The success of this project will depend on a thorough knowledge of the present state of the courses that we teach. This is the first study to address the current state of human anatomy and embryology learning in the physiotherapy degree course. The analysis was performed in first-year students and focussed on the subject designated the structure and function of the human body, skeletal and muscle system anatomy at the Universities of Almería and Jaén. Student opinions were sought on the appropriateness of these subjects to their degree, on the methods used in practice and theory classes and on the evaluation and tutorial systems. Results obtained were similar between the two universities included in this study and indicated that: 1) students have a good opinion of the usefulness of the subject contents in human anatomy and embryology, 2) students prefer the new technologies to traditional educational systems, and 3) students have a positive appreciation of written examination versus oral examination or continuous continuous assessment. These findings will assist teachers of anatomy and embryology to establish approaches to improve the quality of learning in the setting of the European Higher Education Area.
[Show abstract][Hide abstract] ABSTRACT: 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.
International Journal of Nanomedicine 02/2015; 10:1291-306. DOI:10.2147/IJN.S74378 · 4.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The overall survival of patients with pancreatic ductal adenocarcinoma is extremely low. Although gemcitabine is the standard used chemotherapy for this disease, clinical outcomes do not reflect significant improvements, not even when combined with adjuvant treatments. There is an urgent need for prognosis markers to be found. The aim of this study was to analyze the potential value of serum cytokines to find a profile that can predict the clinical outcome in patients with pancreatic cancer and to establish a practical prognosis index that significantly predicts patients’ outcomes. We have conducted an extensive analysis of serum prognosis biomarkers using an antibody array comprising 507 human cytokines. Overall survival was estimated using the Kaplan-Meier method. Univariate and multivariate Cox’s proportional hazard models were used to analyze prognosis factors. To determine the extent that survival could be predicted based on this index, we used the leave-one-out cross-validation model. The multivariate model showed a better performance and it could represent a novel panel of serum cytokines that correlates to poor prognosis in pancreatic cancer. B7-1/CD80, EG-VEGF/PK1, IL-29, NRG1-beta1/HRG1-beta1, and PD-ECGF expressions portend a poor prognosis for patients with pancreatic cancer and these cytokines could represent novel therapeutic targets for this disease.
BioMed Research International 01/2015; in press(6). DOI:10.1155/2015/518284 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Currently, biomedical research is mainly focused on overcoming the major challenges faced by society, including the development of new therapeutic strategies against highly prevalent diseases. Over the past 20 years, considerable advances in this field have been achieved through an interdisciplinary and collaborative approach, enhanced by the development of computer science and its applications in genomics and proteomics. This study centers on platforms for the data management of research assets with high specialization in genomics and proteomics, analyzing the role of web-based databases in the progress made in these areas and evaluating their impact on global scientific production. The web platforms analyzed have proven to be an important resource for stimulating the integration of research data through information exchange. Specialized web search sites facilitate the obtaining of data in these specific areas, creating a trend in current biomedical research. The importance of these platforms is revealed by their impact on scientific production, with some being referenced in more than 100,000 articles and patents. A wider extension of the use of these tools can be expected within the modern society of information.
European Journal of Anatomy 01/2015; 19(2):131-137.
[Show abstract][Hide abstract] ABSTRACT: Advanced colon cancer has a poor prognosis due to the limited effectiveness of current chemotherapies. Treatment failures may be avoided by the utilization of nanoparticles, which can enhance the effects of antitumor drugs, reduce their side effects and increase their directionality. Polystyrene nanoparticles have shown high biocompatibility and appropriate physicochemical properties and may represent a novel and more effective approach against colon cancer. In the present study, polystyrene nanoparticles were synthesized and fluorescently labelled, analyzing their cell internalization, intracellular localization and capacity to release transported molecules in tumour and non-tumour human colon cell lines (T84 and CCD-18). Flow cytometry and fluorescence microscopy studies demonstrated that polystyrene nanoparticles are an effective vehicle for the intracellular delivery of small molecules into colon epithelium cells. The percentage cell uptake was around 100 % in both T84 and CCD-18 cell lines after only 24 h of exposure and was cell confluence-independent. The polystyrene nanoparticles showed no cytotoxicity in either colon cell line. It was found that small molecules can be efficiently delivered into colon cells by using a disulphide bridge as release strategy. Analysis of the influence of the functionalization of the polystyrene nanoparticles surface on the internalization efficiency revealed some morphological changes in these cells. These results demonstrate that polystyrene nanoparticles may improve the transport of biomolecules into colon cells which could have a potential application in chemotherapeutic treatment against colon cancer.
Journal of Nanoparticle Research 01/2015; 17(1). DOI:10.1007/s11051-014-2814-3 · 2.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Colorectal carcinoma is the third most prevalent cancer in the world. In the most advanced stages, the use of chemotherapy induces a poor response and is usually accompanied by other tissue damage. Significant progress based on suicide gene therapy has demonstrated that it may potentiate the classical cytotoxic effects in colorectal cancer. The inconvenience still rests with the targeting and the specificity efficiency. The main target of gene therapy is to achieve an effective vehicle to hand over therapeutic genes safely into specific cells. One possibility is the use of tumor-specific promoters overexpressed in cancers. They could induce a specific expression of therapeutic genes in a given tumor, increasing their localized activity. Several promoters have been assayed into direct suicide genes to cancer cells. This review discusses the current status of specific tumor-promoters and their great potential in colorectal carcinoma treatment.
[Show abstract][Hide abstract] ABSTRACT: Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with poor survival rates. Fast detection of PDAC appears to be the most relevant strategy to improve the long-term survival of patients. Our objective was to identify new markers in peripheral blood that differentiates between PDAC patients and healthy controls. Peripheral blood samples from PDAC patients (n = 18) and controls (n = 18) were analyzed by whole genome cDNA microarray hybridization. The most relevant genes were validated by quantitative real-time PCR (RT-qPCR) in the same set of samples. Finally, our gene prediction set was tested in a blinded set of new peripheral blood samples (n = 30). Microarray studies identified 87 genes differentially expressed in peripheral blood samples from PDAC patients. Four of these genes were selected for analysis by RT-qPCR, which confirmed the previously observed changes. In our blinded validation study, the combination of CLEC4D and IRAK3 predicted the diagnosis of PDAC with 93 % accuracy, with a sensitivity of 86 % and specificity of 100 %. Peripheral blood gene expression profiling is an useful tool for the diagnosis of PDAC. We present a validated four-gene predictor set (ANKRD22, CLEC4D, VNN1, and IRAK3) that may be useful in PDAC diagnosis.
[Show abstract][Hide abstract] ABSTRACT: Background
New biomarkers are needed for the prognosis of advanced colorectal cancer, which remains incurable by conventional treatments. O6-methylguanine DNA methyltransferase (MGMT) methylation and protein expression have been related to colorectal cancer treatment failure and tumor progression. Moreover, the presence in these tumors of cancer stem cells, which are characterized by CD133 expression, has been associated with chemoresistance, radioresistance, metastasis, and local recurrence. The objective of this study was to determine the prognostic value of CD133 and MGMT and their possible interaction in colorectal cancer patients.
MGMT and CD133 expression was analyzed by immunohistochemistry in 123 paraffin-embedded colorectal adenocarcinoma samples, obtaining the percentage staining and intensity. MGMT promoter methylation status was obtained by using bisulfite modification and methylation-specific PCR (MSP). These values were correlated with clinical data, including overall survival (OS), disease-free survival (DFS), tumor stage, and differentiation grade.
Low MGMT expression intensity was significantly correlated with shorter OS and was a prognostic factor independently of treatment and histopathological variables. High percentage of CD133 expression was significantly correlated with shorter DFS but was not an independent factor. Patients with low-intensity MGMT expression and ≥50% CD133 expression had the poorest DFS and OS outcomes.
Our results support the hypothesis that MGMT expression may be an OS biomarker as useful as tumor stage or differentiation grade and that CD133 expression may be a predictive biomarker of DFS. Thus, MGMT and CD133 may both be useful for determining the prognosis of colorectal cancer patients and to identify those requiring more aggressive adjuvant therapies. Future studies will be necessary to determine its clinical utility.
BMC Cancer 07/2014; 14(1):511. DOI:10.1186/1471-2407-14-511 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
Pancreatic ductal adenocarcinoma is a deadly disease because of late diagnosis and chemoresistance. We aimed to find a panel of serum cytokines representing diagnostic and predictive biomarkers for pancreatic cancer.
A cytokine antibody array was performed to simultaneously identify 507 cytokines in sera of patients with pancreatic cancer and healthy controls. The nonparametric Mann-Whitney U test was used to pairwise compare the controls, the pretreated patients, and the posttreated patients. Fold changes greater than or equal to 1.5 or less than or equal to 1/1.5 were considered significant. Receiver operating characteristic curves were used to assess the performance of the model. A leave-one-out cross-validation was used for estimating prediction error.
Comparing the sera of pretreated patients against the control samples, the cytokines fibroblast growth factor 10 (FGF-10/keratinocyte growth factor-2 (KGF-2), chemokine (C-X-C motif) ligand 11 interferon inducible T cell alpha chemokine (I-TAC)/chemokine [C-X-C motif] ligand 11 (CXCL11), oncostatin M (OSM), osteoactivin/glycoprotein nonmetastatic melanoma protein B, and stem cell factor (SCF) were found significantly overexpressed. Besides, the cytokines CD30 ligand/tumor necrosis factor superfamily, member 8 (TNFSF8), chordin-like 2, FGF-10/KGF-2, growth/differentiation factor 15, I-TAC/CXCL11, OSM, and SCF were differentially expressed in response to treatment.
We propose a role for FGF-10/KGF-2, I-TAC/CXCL11, OSM, osteoactivin/glycoprotein nonmetastatic melanoma protein B, and SCF as novel diagnostic biomarkers. CD30 ligand/TNFSF8, chordin-like 2, FGF-10/KGF-2, growth/differentiation factor 15, I-TAC/CXCL11, OSM, and SCF might represent as predictive biomarkers for gemcitabine and erlotinib response of patients with pancreatic cancer.
[Show abstract][Hide abstract] ABSTRACT: Background:
The cancer stem cell (CSC) hypothesis on the origin of cancer has recently gained considerable support. CSCs are tumour cells with the capacity for self-renewal and differentiation that direct the origin and progression of the disease and may be responsible for relapse, metastasis and treatment failures.
This article reviews breast CSCs (BCSCs) phenotyping, clinical implications and clinical trials focused on BCSCs in breast cancer. Relevant studies were found through PubMed and Clinicaltrials.gov databases.
Cancer stem cells are identified and isolated using membrane and cell activity markers; in the case of BCSCs, these are CD44(+) /CD24(low/-) and show aldehyde dehydrogenase activity, alongside their capacity to grow and form mammospheres. The presence of stem cell properties is associated with a worse outcome. Hence, these cells have important clinical implications, and elucidation of the mechanisms underlying their activity will allow the development of novel effective therapies and diagnostic instruments, improving the prognosis of these patients.
Standard treatments are directed against the tumour mass and do not eliminate CSCs. There is therefore a need for specific anti-CSC therapies, and numerous authors are investigating new targets to this end, as reported in this review. It is also necessary for clinical trials to be undertaken to allow this new knowledge to be applied in the clinical setting. However, there have been few trials on anti-BCSCs therapies to date.
European Journal of Clinical Investigation 04/2014; 44(7). DOI:10.1111/eci.12276 · 2.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This article describes the antitumor properties of a new family of merosesquiterpenes, which were synthesized by Diels-Alder cycloaddition of the labdane diene trans-communic acid, highly abundant in Cupressus sempervirens, or its methyl ester, with the appropriate dienophile. These compounds demonstrated potent cytotoxic activity in vitro against human breast, colon, and lung tumor cells. We highlight the elevated activity (IC50: 0.35 ± 0.10 μM) and specificity (TI: 9) of compound 13 against the MCF-7 line, which corresponds to the most prevalent breast cancer cell subtype, luminal A. It was found that compound 13 exerts its anti-tumor action by inducing oxidative stress, arresting the cell cycle in stages G0-G1, and activating apoptosis, which are all associated with low cyclin D1 regulation, pRb hypophosphorylation, increased expression of p27 and p53, and poly (ADP-ribose) polymerase (PARP) fractioning. Epithelial-mesenchymal transition, a phenomenon associated with metastasis promotion and a worsened prognosis also appeared to be inhibited by compound 13. In addition, it markedly reduced tumor development in immunocompetent C57BL/6 mice with allografts of E0771 mouse breast tumor cells (luminal A subtype). According to these findings, this new family of compounds, especially compound 13, may be highly useful in the treatment of human breast cancer.
European Journal of Medicinal Chemistry 03/2014; 79C:1-12. DOI:10.1016/j.ejmech.2014.03.071 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Our aim was to evaluate the impact of anatomy as a multidisciplinary area and to identify trends in research by anatomists over time. Data from three main sources were analyzed: SCImago Journal & Country Rank (SJR), using the number of total documents as indicator; MEDLINE (PubMed) database (1898 through October 2012), using the keyword “anatomy” in the “affiliation” field; and the Journal Citation Report (JCR), gathering impact factor and quartile data. The number of publications by anatomists increased between 1898 and 1941, followed by a reduction until 1961 and then by a marked rise to reach 36,686 between 2002 and 2012. After 1941, anatomists began to publish in journals from JCR categories other than “Anatomy & Morphology”, especially after 1962. Between 2007 and 2012, only 22.23 % of articles by anatomists in JCR-indexed journals were in the “Anatomy & Morphology” area and 77.77 % in journals from other categories; 58 % of their articles were in journals in the first and second quartiles. The contribution of anatomists to scientific knowledge is high quality and considerably greater than indicated by the SJR database. This input is especially relevant in the Neurosciences, Cell Biology, and Biology categories. In addition, more than two-thirds of manuscripts by anatomists appear in JCR-ranked publications, and more than half in the top two quartiles of the impact factor ranking. Our results show that the scientific production of anatomists has improved the quantity and quality of multi-disciplinary scientific activity in different knowledge areas.