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The therapeutic potential of mTOR inhibitors in breast cancer
Author(s) -
Steelman Linda S.,
Martelli Alberto M.,
Cocco Lucio,
Libra Massimo,
Nicoletti Ferdinando,
Abrams Stephen L.,
McCubrey James A.
Publication year - 2016
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/bcp.12958
Subject(s) - mtorc1 , pi3k/akt/mtor pathway , mechanistic target of rapamycin , cancer research , everolimus , exemestane , pten , cancer , kinase , pharmacology , biology , medicine , breast cancer , aromatase , oncology , signal transduction , microbiology and biotechnology
Rapamycin and modified rapamycins (rapalogs) have been used to prevent allograft rejection after organ transplant for over 15 years. The mechanistic target of rapamycin (mTOR) has been determined to be a key component of the mTORC1 complex which consists of the serine/threonine kinase TOR and at least five other proteins which are involved in regulating its activity. Some of the best characterized substrates of mTORC1 are proteins which are key kinases involved in the regulation of cell growth (e.g., p70S6K) and protein translation (e.g., 4E‐BP1). These proteins may in some cases serve as indicators to sensitivity to rapamycin‐related therapies. Dysregulation of mTORC1 activity frequently occurs due to mutations at, or amplifications of, upstream growth factor receptors (e.g., human epidermal growth factor receptor‐2, HER2) as well as kinases (e.g., PI3K) and phosphatases (e.g., PTEN) critical in the regulation of cell growth. More recently, it has been shown that certain rapalogs may enhance the effectiveness of hormonal‐based therapies for breast cancer patients who have become resistant to endocrine therapy. The combined treatment of certain rapalogs (e.g., everolimus) and aromatase inhibitors (e.g., exemestane) has been approved by the United States Food and Drug Administration (US FDA) and other drug regulatory agencies to treat estrogen receptor positive (ER+) breast cancer patients who have become resistant to hormonal‐based therapies and have progressed. This review will summarize recent basic and clinical research in the area and evaluate potential novel therapeutic approaches.