The Antifolates

ArticleinHematology/oncology clinics of North America 26(3):629-48, ix · June 2012with17 Reads
DOI: 10.1016/j.hoc.2012.02.002 · Source: PubMed
Abstract
This article focuses on the cellular, biochemical, and molecular pharmacology of antifolates and how a basic understanding of the mechanism of action of methotrexate, its cytotoxic determinants, mechanisms of resistance, and transport into and out of cells has led to the development of a new generation of antifolates, a process that continues in the laboratory and in the clinics. New approaches to folate-based cancer chemotherapy are described based on the targeted delivery of drugs to malignant cells.
    • "A methotrexate (MTX) was chosen as a model anticancer drug. This is one of the oldest antifolate drugs widely used in the treatment of cancer, rheumatoid arthritis, and other diseases (Visentin et al. 2012). There have already been studies of HES as a drug carrier , including conjugates with bioactive compounds such as deferoxamine (Mousa et al. 1992) and HES-based hydrogels for the controlled release of biomacromolecules (Wohl-Bruhn et al. 2012): however, to our knowledge, this is the first application of antifolate covalently conjugated to HES in experimental anticancer treatment. "
    [Show abstract] [Hide abstract] ABSTRACT: At present, effective anticancer therapy remains one of the most challenging tasks facing the scientific community. A major limitation to most conventional low-molecular weight anticancer chemotherapeutics is their unfavourable uptake by healthy tissue, fast metabolism and lack of tumour cell selectivity. One way to solve this problem is the application of hybrid nanoparticles containing widely known therapeutic substances. This study was performed with the aim of investigating the potential of use hydroxyethyl starch (HES) as a high-molecular weight carrier for anticancer drug (methotrexate, MTX). HES-MTX conjugates were characterized in terms of MTX content, hydrodynamic size, zeta potential, and drug release kinetics. In vitro biological characteristics were determined using different cancer cell lines. The antitumor effect in vivo was tested in NOD/SCID mice subcutaneously inoculated with MV-4-11 human leukaemia cells and CDF1 mice intraperitoneally inoculated with P388 murine leukaemia cells. The in vivo experiments revealed the considerably higher antitumor efficacy of HES-MTX conjugates in comparison to unconjugated drug. The results presented in this article demonstrate that the application of HES as an anticancer drug carrier can improve the treatment efficacy and have significant implications for the future design and implementation of drug-carrier conjugates. The study should help create new opportunities in the design of HES-based innovative drug-carrier conjugates.
    Full-text · Article · Jun 2014
    • "Most of the deaths associated with breast cancer are a result of metastasis and its physiologic effects on morbidity and mortality.1 Methotrexate (MTX) is an antimetabolic drug that remains important in the treatment of a variety of malignancies, such as breast cancer.2 MTX presents high structural homology to folic acid, being able to bind to folic acid receptor.3 The mechanism of action consists of transportation into cells mostly by the reduced folate carrier (RFC). "
    [Show abstract] [Hide abstract] ABSTRACT: Breast cancer is the most frequent cancer affecting women. Methotrexate (MTX) is an antimetabolic drug that remains important in the treatment of breast cancer. Its efficacy is compromised by resistance in cancer cells that occurs through a variety of mechanisms. This study evaluated apoptotic cell death and cell cycle arrest induced by an MTX derivative (MTX diethyl ester [MTX(OEt)2]) and MTX(OEt)2-loaded lipid-core nanocapsules in two MTX-resistant breast adenocarcinoma cell lines, MCF-7 and MDA-MB-231. The formulations prepared presented adequate granulometric profile. The treatment responses were evaluated through flow cytometry. Relying on the mechanism of resistance, we observed different responses between cell lines. For MCF-7 cells, MTX(OEt)2 solution and MTX(OEt)2-loaded lipid-core nanocapsules presented significantly higher apoptotic rates than untreated cells and cells incubated with unloaded lipid-core nanocapsules. For MDA-MB-231 cells, MTX(OEt)2-loaded lipid-core nanocapsules were significantly more efficient in inducing apoptosis than the solution of the free drug. S-phase cell cycle arrest was induced only by MTX(OEt)2 solution. The drug nanoencapsulation improved apoptosis induction for the cell line that presents MTX resistance by lack of transport receptors.
    Full-text · Article · Mar 2014
  • [Show abstract] [Hide abstract] ABSTRACT: This second article in our two-part series on targeted therapies in solid tumors covers the emergence of targeted therapies for the treatment of two common malignancies: lung cancer and breast cancer. In these two tumors, the identification of a promising target has led to successful preliminary applications, and eventually to further advances through drug development and the fine tuning of patient selection. As a result, the percentage of patients with breast or lung cancer who are benefiting from targeted agents has steadily increased, even if the majority are still treated with conventional cytotoxic regimens. We also review the latest therapeutic strategies for colorectal and gynecologic cancers--because these offer an instructive contrast. The curative regimens that have been developed for these two tumors--even those in more advanced stages--have included combinations of surgery and/or radiation with chemotherapy. The Cancer Genome Atlas has revealed complexities in the biology of these tumors that underscore the fact that reliance on selective DNA-damaging agents such as platinums, antimetabolites, and antimitotic agents will continue for some time. We conclude that the therapeutic progress that may arise from the study of molecular pathways will be due not only to the development of new targeted therapies, but also to a better understanding of older drugs developed empirically in the past. Taken together, these two types of advance illustrate the remarkable overall effect of modern cancer therapeutics' focus on tumor biology and tumor immunology.
    Article · Nov 2012
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