Abstract
The PI3K/mTOR-pathway is the most commonly dysregulated pathway in epithelial cancers and represents an important target for cancer therapeutics. Here, we show that dual inhibition of PI3K/mTOR in ovarian cancer-spheroids leads to death of inner matrix-deprived cells, whereas matrix-attached cells are resistant. This matrix-associated resistance is mediated by drug-induced upregulation of cellular survival programs that involve both FOXO-regulated transcription and cap-independent translation. Inhibition of any one of several upregulated proteins, including Bcl-2, EGFR, or IGF1R, abrogates resistance to PI3K/mTOR inhibition. These results demonstrate that acute adaptive responses to PI3K/mTOR inhibition in matrix-attached cells resemble well-conserved stress responses to nutrient and growth factor deprivation. Bypass of thisresistance mechanism through rational design of drug combinations could significantly enhance PI3K-targeted drug efficacy.
Original language | English |
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Pages (from-to) | 227-239 |
Number of pages | 13 |
Journal | Cancer Cell |
Volume | 21 |
Issue number | 2 |
DOIs | |
State | Published - 14 Feb 2012 |