RT Journal Article
SR Electronic
T1 Combination Small Molecule MEK and PI3K Inhibition Enhances Uveal Melanoma Cell Death in a Mutant <em>GNAQ-</em> and <em>GNA11</em>-Dependent Manner
JF Clinical Cancer Research
JO Clin Cancer Res
FD American Association for Cancer Research
SP 4345
OP 4355
DO 10.1158/1078-0432.CCR-11-3227
VO 18
IS 16
A1 Khalili, Jahan S.
A1 Yu, Xiaoxing
A1 Wang, Ji
A1 Hayes, Brendan C.
A1 Davies, Michael A.
A1 Lizee, Gregory
A1 Esmaeli, Bita
A1 Woodman, Scott E.
YR 2012
UL http://clincancerres.aacrjournals.org/content/18/16/4345.abstract
AB Purpose: Activating Q209L/P mutations in GNAQ or GNA11 (GNAQ/11) are present in approximately 80% of uveal melanomas. Mutant GNAQ/11 are not currently therapeutically targetable. Inhibiting key down-stream effectors of GNAQ/11 represents a rational therapeutic approach for uveal melanomas that harbor these mutations. The mitogen-activated protein/extracellular signal–regulated kinase/mitogen-activated protein kinase (MEK/MAPK) and PI3K/AKT pathways are activated in uveal melanoma. In this study, we test the effect of the clinically relevant small molecule inhibitors GSK1120212 (MEK inhibitor) and GSK2126458 (pan class I PI3K inhibitor) on uveal melanoma cells with different GNAQ/11 mutation backgrounds. Experimental Design: We use the largest set of genetically annotated uveal melanoma cell lines to date to carry out in vitro cellular signaling, cell-cycle regulation, growth, and apoptosis analyses. RNA interference and small molecule MEK and/or PI3K inhibitor treatment were used to determine the dependency of uveal melanoma cells with different GNAQ/11 mutation backgrounds on MEK/MAPK and/or PI3K/AKT signaling. Proteomic network analysis was done to unveil signaling alterations in response to MEK and/or PI3K small molecule inhibition. Results: GNAQ/11 mutation status was not a determinant of whether cells would undergo cell-cycle arrest or growth inhibition to MEK and/or phosphoinositide 3-kinase (PI3K) inhibition. A reverse correlation was observed between MAPK and AKT phosphorylation after MEK or PI3K inhibition, respectively. Neither MEK nor PI3K inhibition alone was sufficient to induce apoptosis in the majority of cell lines; however, the combination of MEK + PI3K inhibitor treatment resulted in the marked induction of apoptosis in a GNAQ/11 mutant–dependent manner. Conclusions: MEK + PI3K inhibition may be an effective combination therapy in uveal melanoma, given the inherent reciprocal activation of these pathways within these cells. Clin Cancer Res; 18(16); 4345–55. ©2012 AACR.