mTOR signaling and drug development in cancer.
Mammalian target of rapamycin (mTOR) is a protein kinase of the PI3K/Akt signaling pathway. Activation of mTOR in response to growth, nutrient and energy signals leads to an increase in protein synthesis, which is required for tumor development. This feature makes mTOR an attractive target for cancer therapy. First-generation mTOR inhibitors are sirolimus derivatives (rapalogs), which have been evaluated extensively in cancer patients. Everolimus and temsirolimus are already approved for the treatment of renal-cell carcinoma. Temsirolimus is also approved for the treatment of mantle-cell lymphoma. These drugs, in addition to ridaforolimus (formerly deforolimus) and sirolimus, are currently being evaluated in clinical trials of various cancers. Second-generation mTOR inhibitors are small molecules that target the kinase domain, and have also entered clinical development. Clinical trials are underway to identify additional malignancies that respond to mTOR inhibitors, either alone or in combination with other therapies. Future research should evaluate the optimal drug regimens, schedules, patient populations, and combination strategies for this novel class of agents.
Dancey
Janet
J
Ontario Institute for Cancer Research, MaRS Centre, South Tower, 101 College Street, Suite 800, Toronto, ON M5G 0A3, Canada. janet.dancey@oicr.on.ca
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D015195:Drug Design; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy* / Q000503:physiopathology; D010766:Phosphorylation; D015398:Signal Transduction; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors*
D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus