Fernando Rodríguez-Serrano

Nanomedicine: Application Areas and Development Prospects

Nanotechnology, along with related concepts such as nanomaterials, nanostructures and nanoparticles, has become a priority area for scientific research and technological development. Nanotechnology, i.e., the creation and utilization of materials and devices at nanometer scale, already has multiple applications in electronics and other fields. However, the greatest expectations are for its application in biotechnology and health, with the direct impact these could have on the quality of health in future societies. The emerging discipline of nanomedicine brings nanotechnology and medicine together in order to develop novel therapies and improve existing treatments. In nanomedicine, atoms and molecules are manipulated to produce nanostructures of the same size as biomolecules for interaction with human cells. This procedure offers a range of new solutions for diagnoses and “smart” treatments by stimulating the body’s own repair mechanisms. It will enhance the early diagnosis and treatment of diseases such as cancer, diabetes, Alzheimer’s, Parkinson’s and cardiovascular diseases. Preventive medicine may then become a reality.

MGMT promoter methylation status and MGMT and CD133 immunohistochemical expression as prognostic markers in glioblastoma patients treated with temozolomide plus radiotherapy

BackgroundThe 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.MethodsSeventy-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.ResultsThe 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.ConclusionsOur 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.

Human cardiac tissue induces transdifferentiation of adult stem cells towards cardiomyocytes.

BACKGROUND AIMS The goal was to induce the transdifferentiation (or conversion) of human adipose-derived stem cells to cardiomyocytes using an intracellular extract obtained from adult human heart tissue. METHODS Human adult stem cells from lipoaspirates were transiently permeabilized, exposed to human atrial extracts and allowed to recover in culture. RESULTS After 21 days, the cells acquired a cardiomyocyte phenotype, as demonstrated by morphologic changes (appearance of binucleate, striated cells and branching fibers), immunofluorescence detection of cardiac-specific markers (connexin-43, sarcomeric alpha-actinin, cardiac troponin I and T, and desmin) and the presence of cardiomyocyte-related genes analyzed by reverse transcription-polymerase chain reaction (cardiac myosin light chain 1, alpha-cardiac actin, cardiac troponin T and cardiac beta-myosin). CONCLUSIONS We have demonstrated for the first time that adult cardiomyocytes obtained from human donors retain the capacity to induce cardiomyocyte differentiation of mesenchymal stromal cells. The use of autologous extracts for reprogramming adult stem cells may have potential therapeutic implications for treating heart disease.

5-Fluorouracil derivatives: a patent review

Introduction: The fluorinated analog of uracil 5-FU is an antimetabolite, active against a wide range of solid tumors. The main mechanism of action consists in interfering with DNA synthesis and mRNA translation. However, patients treated with 5-FU display several side effects, a result of its nonspecific cytotoxicity for tumor cells. Numerous modifications of the 5-FU structure have been performed in order to overcome these disadvantages. Areas covered: In this review, the metabolic pathways, pharmacokinetics and clinical pharmacology of 5-FU are briefly introduced. Moreover, several derivatives developed and patented, including oral 5-FU prodrugs and combinations with other active compounds, are presented. Finally, new innovative methods for administration and vehiculization of 5-FU and its derivatives are described. Expert opinion: The search for less toxic 5-FU derivatives, which diminish or circumvent some of its disadvantages, has allowed the development of selective antitumor prodrugs and novel methods for tissue-specific drug delivery. Although some of these oral prodrugs are being used clinically, either alone or in combination therapy with other anticancer agents, it seems that the potential of personalized medicine, including pharmacogenomics and targeted therapy with novel 5-FU derivatives, will improve the management and clinical responses of patients treated with 5-FU-based therapy.

New (RS)-benzoxazepin-purines with antitumour activity: The chiral switch from (RS)-2,6-dichloro-9-[1-(p-nitrobenzenesulfonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepin-3-yl]-9H-purine.

Completing an SAR study, a series of (RS)-6-substituted-7- or 9-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-7H or 9H-purines has been prepared under microwave-assisted conditions. Their antiproliferative activities on MCF-7 and MDA-MB-231 cancerous cell lines are presented, being the majority of the IC(50) values below 1μM. The most active compound (RS)-2,6-dichloro-9-[1-(p-nitrobenzenesulfonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepin-3-yl]-9H-purine (14) presents an IC(50) of 0.166μM against the human cancerous cell line MDA-MB-231. Compound 14 was the most selective against the human breast adenocarcinoma MCF-7 and MDA-MB-231 cancer cell lines (Therapeutic Indexes, TIs=5.1 and 11.0, respectively) in relation to the normal one MCF-10A. (RS)-14 was resolved into its enantiomers. Both enantiomers are equally potent, but more potent than the corresponding racemic mixture. (R)-14 induces apoptosis against MCF-7 up to 52.50% of cell population after 48h, being more potent than the clinical-used drug paclitaxel (43%). (RS)-14 induces no acute toxicity in mice after two weeks of treatment.

Regulatory systems in bone marrow for hematopoietic stem/progenitor cells mobilization and homing.

Regulation of hematopoietic stem cell release, migration, and homing from the bone marrow (BM) and of the mobilization pathway involves a complex interaction among adhesion molecules, cytokines, proteolytic enzymes, stromal cells, and hematopoietic cells. The identification of new mechanisms that regulate the trafficking of hematopoietic stem/progenitor cells (HSPCs) cells has important implications, not only for hematopoietic transplantation but also for cell therapies in regenerative medicine for patients with acute myocardial infarction, spinal cord injury, and stroke, among others. This paper reviews the regulation mechanisms underlying the homing and mobilization of BM hematopoietic stem/progenitor cells, investigating the following issues: (a) the role of different factors, such as stromal cell derived factor-1 (SDF-1), granulocyte colony-stimulating factor (G-CSF), and vascular cell adhesion molecule-1 (VCAM-1), among other ligands; (b) the stem cell count in peripheral blood and BM and influential factors; (c) the therapeutic utilization of this phenomenon in lesions in different tissues, examining the agents involved in HSPCs mobilization, such as the different forms of G-CSF, plerixafor, and natalizumab; and (d) the effects of this mobilization on BM-derived stem/progenitor cells in clinical trials of patients with different diseases.

Anticancer activity of (1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-pyrimidines and -purines against the MCF-7 cell line: Preliminary cDNA microarray studies

Completing a SAR study, a series of (RS)-1- or 3-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-pyrimidines and (RS)-6-substituted-7- or 9-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-7H- or 9H-purines have been prepared. Their antiproliferative activities on MCF-7 cells are here presented and discussed. (RS)-6-Chloro-9-[1-(9H-9-fluorenylmethoxycarbonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl]-9H-purine (28) is the most active (IC(50)=0.67+/-0.18 microM) of the series so far described. cDNA microarray technology reveals potential drug targets, which are mainly centred on apoptosis regulatory pathway genes.

New Gene Therapy Strategies for Cancer Treatment: A Review of Recent Patents

Cancer is the second leading cause of death in the Western world. The limited successes of available treatments for cancer mean that new strategies need to be developed. The possibility of modifying the cancer cell with the introduction of genetic material opens the way to a new approach based on gene therapy. There are still many technical difficulties to be overcome, but recent advances in the molecular and cellular biology of gene transfer have made it likely that gene therapy will soon start to play an increasing role in clinical practice, particularly in the treatment of cancer. Gene therapy will probably be the therapeutic option in cases in which conventional treatments such as surgery, radiotherapy and chemotherapy have failed. The development of modified vectors, and an improved understanding of interactions between the vector and the human host, are generating inventions that are being protected by patents due to the considerable interest of industry for their possible commercialization. We review the latest strategies, patented and/or under clinical trial, in cancer gene therapy. These include patents that cover the use of modified vectors to increase the security and specificity, recombining adenovirus that leads to loss or gain of gene function, activation of the patients own immune cells to eliminate cancer cells by expression of molecules that enhance immune responses, silencing genes related to the development of drug resistance in patients, inhibition of angiogenesis of solid tumors by targeting the tumor vasculature, and the development of enzymes that destroy viral or cancerous genetic material.

Cancer stem cells and their implication in breast cancer

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.

Synthesis and anticancer activity of (R,S)-9-(2,3-dihydro-1,4-benzoxathiin-3-ylmethyl)-9H-purines.

A series of eleven 2‐ and 6‐substituted (R,S)‐9‐(2,3‐dihydro‐1,4‐benzoxathiin‐3‐ylmethyl)‐9H‐purine derivatives was obtained by applying a standard Mitsunobu protocol that led to a six‐membered ring contraction from (R,S)‐3,4‐dihydro‐2H‐1,5‐benzoxathiepin‐3‐ol via an episulfonium intermediate. The signal ∼δ=151 ppm, which corresponds to the C4′ carbon atom, is unequivocal proof of the N9′ regioisomer. The potential of the target molecules as anticancer agents is reflected in their activity against the MCF‐7 cancer cell line. The most active compounds have IC50 values of (6.18±1.70) and (8.97±0.83) μM. The results indicate that the anticancer activity for the most active compounds is correlated with their capacity to induce apoptosis.