Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.44 (P-glycoprotein)
 13,344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent progress in development of molecular cancer therapeutics revealed new types of antitumor drugs, such as Herceptin, Gleevec, and Iressa as potent therapeutics for each specific tumor. We have been working on molecular cancer therapeutics, and in particular, those related to drug resistance, Here, I describe several resistance mechanisms, including apoptosis regulation, cellular stress response and cellular survival signals which have show close relevance to drug resistance. P-glycoprotein (P-gp) is the key molecule in multidrug resistance (MDR) and a good target for chemotherapy. Proteasome is involved in the resistance mechanism to topo II-targeted chemotherapy in solid tumors. Apoptosis program in tumor cells plays a critical role in chemotherapy-induced tumor cell killing, and the blockade of the apoptosis-inducing pathway could be another mechanism for drug resistance. Glyoxalase I is a molecule involved in apoptosis resistance mechanism in tumors. Survival (antiapoptosis) signals are the good targets for various antitumor drugs to overcome innate drug resistance. Our present studies provide novel targets for effective molecular cancer therapeutics in future.
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PMID:Molecular cancer therapeutics: recent progress and targets in drug resistance. 1270 87

There is no consensus on second-line treatment for women with metastatic or locally advanced breast cancer over-expressing HER-2 protein in whom treatment with a taxane + trastuzumab has failed. Capecitabine is one option. Adding lapatinib does not prolong survival. Trastuzumab emtansine (Kadcyla, Roche) has received EU marketing authorisation for use in this setting. It consists of two covalently bound drugs: trastuzumab, a monoclonal antibody that binds to HER-2 receptors, and DM1, a cytotoxic microtubule inhibitor. DM1 is derived from maytansine, a cytotoxic drug abandoned in the 1980s because it proved to be too toxic after systemic administration. Clinical evaluation of trastuzumab emtansine is based on an unblinded trial versus capecitabine + lapatinib in 991 patients. The use of lapatinib in all patients in the control group is questionable. An interim analysis suggested that overall survival was about 6 months longer with trastuzumab emtansine (30.9 versus 25.1 months). In addition to the adverse effects of trastuzumab (thrombocytopenia, heart failure, etc.), trastuzumab emtansine causes frequent and potentially life-threatening hepatic toxicity, peripheral neuropathy, and urinary tract infections. Trastuzumab emtansine appears to be less toxic to the skin and mucous membranes than the capecitabine + lapatinib combination. DM1 is metabolised by cytochrome P450 isoenzymes CYP3A4 and CYP3A5 and is also a P-glycoprotein substrate, creating a potential risk of multiple pharmacokinetic interactions. Trastuzumab emtansine appears to be teratogenic and embryotoxic. The international nonproprietary name of this drug is easily confused with trastuzumab. In practice, it is best to at least wait for the full results of the only available comparative trial of trastuzumab emtansine before drawing conclusions about its harm-benefit balance and its possible use if it represents a real therapeutic advance.
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PMID:Trastuzumab emtansine. An inadequately assessed combination of two cytotoxic drugs. 2562 44