Abstract
Background: Atypical teratoid/rhabdoid tumors (AT/RTs) are deadly pediatric brain tumors driven by LIN28. Mammalian target of rapamycin (mTOR) is activated in many deadly, drug-resistant cancers and governs important cellular functions such as metabolism and survival. LIN28 regulates mTOR in normal cells. We therefore hypothesized that mTOR is activated downstream of LIN28 in AT/RT, and the brain-penetrating mTOR complex 1 and 2 (mTORC1/2) kinase inhibitor TAK228 would reduce AT/RT tumorigenicity. Methods: Activation of mTOR in AT/RT was determined by measuring pS6 and pAKT (Ser473) by immunohistochemistry on tissue microarray of 18 primary AT/RT tumors. In vitro growth assays (BrdU and MTS), death assays (CC3, c-PARP by western blot), and survival curves of AT/RT orthotopic xenograft models were used to measure the efficacy of TAK228 alone and in combination with cisplatin. Results: Lentiviral short hairpin RNA-mediated knockdown of LIN28A led to decreased mTOR activation. Primary human AT/RT had high levels of pS6 and pAKT (Ser473) in 21% and 87% of tumors by immunohistochemistry. TAK228 slowed cell growth, induced apoptosis in vitro, and nearly doubled median survival of orthotopic xenograft models of AT/RT. TAK228 combined with cisplatin synergistically slowed cell growth and enhanced cisplatininduced apoptosis. Suppression of AKT sensitized cells to cisplatin-induced apoptosis and forced activation of AKT protected cells. Combined treatment with TAK228 and cisplatin significantly extended survival of orthotopic xenograft models of AT/RT compared with each drug alone. Conclusions: TAK228 has efficacy in AT/RT as a single agent and synergizes with conventional chemotherapies by sensitizing tumors to cisplatin-induced apoptosis. These results suggest TAK228 may be an effective new treatment for AT/RT.
Original language | English (US) |
---|---|
Pages (from-to) | 1361-1371 |
Number of pages | 11 |
Journal | Neuro-oncology |
Volume | 19 |
Issue number | 10 |
DOIs | |
State | Published - Oct 1 2017 |
Keywords
- INK128
- MLN0128
- Pediatric brain tumor
- Sapanisertib
- TAK228
ASJC Scopus subject areas
- Oncology
- Clinical Neurology
- Cancer Research