Cancer chemotherapy can fail in many ways. One of the most significant is the development of multiple drug resistance (MDR), which constitutes a serious clinical problem. The development of MDR relates to the expression of a major membrane pump, P-glycoprotein (P-gp). Thus, currently one of the goals of experimental and clinical oncology is to decrease its activity. So far, many different P-gp ...

The development of resistance poses a serious problem in the therapy cancer due to necessity multiple-drug and unlimited treatment affected patients. In chronic myeloid leukemia (CML), introduction imatinib has revolutionized therapy. persistence an untreatable stem cell pool other resistance-causing factors, however, also impede cure this malignancy. New therapeutic approaches are therefore es...

RNA interference is a post-transcriptional mechanism by which double-stranded RNA specifically silence expression of a corresponding gene. Small interfering double-stranded RNA (siRNA) of 21–23 nucleotides can induce the process of RNA interference. Studies from our laboratory have shown that translation of thymidylate synthase (TS) mRNA is controlled by its own protein end-product TS in a nega...

Enhanced control of species of Cryptococcus, non-fermentative yeast pathogens, was achieved by chemosensitization through co-application of certain compounds with a conventional antimicrobial drug. The species of Cryptococcus tested showed higher sensitivity to mitochondrial respiratory chain (MRC) inhibition compared to species of Candida. This higher sensitivity results from the inability of ...

P-glycoprotein was purified from multidrug-resistant Chinese hamster ovary CHRB30 cells by a combination of anion exchange and immunoaffinity chromatography. The P-glycoprotein was about 90% pure and had a Vmax for ATP hydrolysis in detergent solution of 321 nmol/min/mg with a Km of 0.94 mM. The ATPase activity was inhibited by low concentrations of vanadate and N-ethylmaleimide, but unaffected...

Clinical circumvention of multidrug resistance (MDR) is a Sisyphian task faced in the treatment of many cancers. Identification of several mechanisms of acquired MDR has led to the development of chemosensitizing agents that counter specific mechanisms of MDR. Initial successes in therapy using "chemosensitizers" often culminate in relapse due to the multifactorial nature of acquired MDR. There...

Many human cancers that are initially responsive to chemotherapy eventually fail to respond to treatment. For some drugs, dose escalation that may be required for a cure cannot be achieved because sensitive tissues such as bone marrow (BM) limit cytotoxic therapy. Approaches to prevent or circumvent BM toxicity are therefore a high priority of research on dose escalation protocols. In this stud...

Synergistic combination therapy by integrating chemotherapeutics and chemosensitizers into nanoparticles has demonstrated great potential to reduce side effects, overcome multidrug resistance (MDR), and thus improve therapeutic efficacy. However, with regard to the nanocarriers for multidrug codelivery, it remains a strong challenge to maintain design simplicity, while incorporating the desirab...