<p>Supplementary Figures - PDF file 947K, Supplementary Figure 1. Targeted drug response curves of endometrial cancer cells. Endometrial cancer cell lines were incubated with serial dilutions of the targeted therapeutics tested and after 72h cell viability was assessed using CellTiter Blue; Supplementary Figure 2. Mutational profile and PTEN protein expression levels of endometrial cancer cell lines; Supplementary Figure 3. AKT, rpS6 and ERK activation in endometrial cancer cell lines; Supplementary Figure 4. Response of EEC cells to PI3K and RAF/MEK/ERK pathway inhibitors and association with mutation pattern; Supplementary Figure 5. Combination treatment of PI3K and MAPK pathway inhibitors; Supplementary Figure 6. siRNA-mediated KRAS silencing efficiency; Supplementary Figures 7.and 8</p>
ARTICLE ABSTRACT
Purpose: Endometrioid endometrial cancers (EEC) frequently harbor coexisting mutations in phosphoinositide 3-kinase (PI3K) pathway genes, including PTEN, PIK3CA, PIK3R1, and KRAS. We sought to define the genetic determinants of PI3K pathway inhibitor response in EEC cells, and whether PTEN-mutant EEC cell lines rely on p110β signaling for survival.Experimental Design: Twenty-four human EEC cell lines were characterized for their mutation profile and activation state of PI3K and mitogen-activated protein kinase (MAPK) signaling pathway proteins. Cells were treated with pan-class I PI3K, p110α, and p110β isoform-specific, allosteric mTOR, mTOR kinase, dual PI3K/mTOR, mitogen-activated protein/extracellular signal–regulated kinase (MEK), and RAF inhibitors. RNA interference (RNAi) was used to assess effects of KRAS silencing in EEC cells.Results: EEC cell lines harboring PIK3CA and PTEN mutations were selectively sensitive to the pan-class I PI3K inhibitor GDC-0941 and allosteric mTOR inhibitor temsirolimus, respectively. Subsets of EEC cells with concurrent PIK3CA and/or PTEN and KRAS mutations were sensitive to PI3K pathway inhibition, and only 2 of 6 KRAS-mutant cell lines showed response to MEK inhibition. KRAS RNAi silencing did not induce apoptosis in KRAS-mutant EEC cells. PTEN-mutant EEC cell lines were resistant to the p110β inhibitors GSK2636771 and AZD6482, and only in combination with the p110α selective inhibitor A66 was a decrease in cell viability observed.Conclusions: Targeted pan-PI3K and mTOR inhibition in EEC cells may be most effective in PIK3CA- and PTEN-mutant tumors, respectively, even in a subset of EECs concurrently harboring KRAS mutations. Inhibition of p110β alone may not be sufficient to sensitize PTEN-mutant EEC cells and combination with other targeted agents may be required. Clin Cancer Res; 19(13); 3533–44. ©2013 AACR.
