TY - JOUR
T1 - Integrated molecular and clinical analysis of AKT activation in metastatic melanoma
AU - Davies, Michael A.
AU - Stemke-Hale, Katherine
AU - Lin, E.
AU - Tellez, Carmen
AU - Deng, Wanleng
AU - Gopal, Yennu N.
AU - Woodman, Scott E.
AU - Calderone, Tiffany C.
AU - Ju, Zhenlin
AU - Lazar, Alexander J.
AU - Prieto, Victor G.
AU - Aldape, Kenneth
AU - Mills, Gordon B.
AU - Gershenwald, Jeffrey E.
PY - 2009/12/15
Y1 - 2009/12/15
N2 - Purpose: Activation of the phosphoinositide 3-kinase (PI3K)-AKT pathway has been implicated in melanoma based primarily on the prevalence of mutations in PTEN and NRAS. To improve our understanding of the regulation and clinical significance of the PI3K-AKT pathway in melanoma, we quantitatively measured the levels of phosphorylated AKT, its substrate GSK3α/β, and its negative regulator PTEN in clinical metastases. Results were compared with mutational status, clinical outcomes, and sites of metastasis. Experimental Design: DNA and protein were isolated from dissected frozen melanoma metastases (n = 96). Activating mutations of BRAF, NRAS, AKT, PIK3CA, and KIT were detected by mass spectroscopy genotyping. Phosphorylated AKT (Ser473 and Thr308), P-GSK3α/β, and PTEN protein expression were measured by reverse-phase protein array. A panel of human melanoma cells lines (n = 58) was analyzed for comparison. Results: BRAF-mutant tumors had higher levels of P-AKT-Ser473 (P = 0.01), P-AKTThr308 (P = 0.002), and P-GSK3α/β (P = 0.08) than NRAS-mutant tumors. Analysis of individual tumors showed that almost all tumors with elevated P-AKT had low PTEN levels; NRAS-mutant tumors had normal PTEN and lower P-AKT. Similar results were observed in melanoma cell lines. Stage III melanoma patients did not differ in overall survival based on activation status of the PI3K-AKT pathway. Brain metastases had significantly higher P-AKT and lower PTEN than lung or liver metastases. Conclusions: Quantitative interrogation of the PI3K-AKT pathway in melanoma reveals unexpected significant differences in AKT activation by NRAS mutation and PTEN loss, and hyperactivation of AKT in brain metastases. These findings have implications for the rational development of targeted therapy for this disease.
AB - Purpose: Activation of the phosphoinositide 3-kinase (PI3K)-AKT pathway has been implicated in melanoma based primarily on the prevalence of mutations in PTEN and NRAS. To improve our understanding of the regulation and clinical significance of the PI3K-AKT pathway in melanoma, we quantitatively measured the levels of phosphorylated AKT, its substrate GSK3α/β, and its negative regulator PTEN in clinical metastases. Results were compared with mutational status, clinical outcomes, and sites of metastasis. Experimental Design: DNA and protein were isolated from dissected frozen melanoma metastases (n = 96). Activating mutations of BRAF, NRAS, AKT, PIK3CA, and KIT were detected by mass spectroscopy genotyping. Phosphorylated AKT (Ser473 and Thr308), P-GSK3α/β, and PTEN protein expression were measured by reverse-phase protein array. A panel of human melanoma cells lines (n = 58) was analyzed for comparison. Results: BRAF-mutant tumors had higher levels of P-AKT-Ser473 (P = 0.01), P-AKTThr308 (P = 0.002), and P-GSK3α/β (P = 0.08) than NRAS-mutant tumors. Analysis of individual tumors showed that almost all tumors with elevated P-AKT had low PTEN levels; NRAS-mutant tumors had normal PTEN and lower P-AKT. Similar results were observed in melanoma cell lines. Stage III melanoma patients did not differ in overall survival based on activation status of the PI3K-AKT pathway. Brain metastases had significantly higher P-AKT and lower PTEN than lung or liver metastases. Conclusions: Quantitative interrogation of the PI3K-AKT pathway in melanoma reveals unexpected significant differences in AKT activation by NRAS mutation and PTEN loss, and hyperactivation of AKT in brain metastases. These findings have implications for the rational development of targeted therapy for this disease.
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U2 - 10.1158/1078-0432.CCR-09-1985
DO - 10.1158/1078-0432.CCR-09-1985
M3 - Article
C2 - 19996208
AN - SCOPUS:73349128709
SN - 1078-0432
VL - 15
SP - 7538
EP - 7546
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 24
ER -