Combined targeting of MEK and PI3K/mTOR effector pathways is necessary to effectively inhibit NRAS mutant melanoma in vitro and in vivo

Activating mutations in the neuroblastoma rat sarcoma viral oncogene homolog (NRAS) gene are common genetic events in malignant melanoma being found in 15–25% of cases. NRAS is thought to activate both mitogen activated protein kinase (MAPK) and PI3K signaling in melanoma cells. We studied the influence of different components on the MAP/extracellular signal-regulated (ERK) kinase (MEK) and PI3K/mammalian target of rapamycin (mTOR)-signaling cascade in NRAS mutant melanoma cells. In general, these cells were more sensitive to MEK inhibition compared with inhibition in the PI3K/mTOR cascade. Combined targeting of MEK and PI3K was superior to MEK and mTOR1,2 inhibition in all NRAS mutant melanoma cell lines tested, suggesting that PI3K signaling is more important for cell survival in NRAS mutant melanoma when MEK is inhibited. However, targeting of PI3K/mTOR1,2 in combination with MEK inhibitors is necessary to effectively abolish growth of NRAS mutant melanoma cells in vitro and regress xenografted NRAS mutant melanoma. Furthermore, we showed that MEK and PI3K/mTOR1,2 inhibition is synergistic. Expression analysis confirms that combined MEK and PI3K/mTOR1,2 inhibition predominantly influences genes in the rat sarcoma (RAS) pathway and growth factor receptor pathways, which signal through MEK/ERK and PI3K/mTOR, respectively. Our results suggest that combined targeting of the MEK/ERK and PI3K/mTOR pathways has antitumor activity and might serve as a therapeutic option in the treatment of NRAS mutant melanoma, for which there are currently no effective therapies.

[1]  Gerald C. Chu,et al.  Oncogenic NRAS signaling differentially regulates survival and proliferation in melanoma , 2012, Nature Medicine.

[2]  James S. Duncan,et al.  Combined PI3K/mTOR and MEK Inhibition Provides Broad Antitumor Activity in Faithful Murine Cancer Models , 2012, Clinical Cancer Research.

[3]  S. Woodman,et al.  Combination Small Molecule MEK and PI3K Inhibition Enhances Uveal Melanoma Cell Death in a Mutant GNAQ- and GNA11-Dependent Manner , 2012, Clinical Cancer Research.

[4]  J. Christensen,et al.  Combination of a MEK inhibitor at sub-MTD with a PI3K/mTOR inhibitor significantly suppresses growth of lung adenocarcinoma tumors in KrasG12D-LSL mice , 2012, Cancer Chemotherapy and Pharmacology.

[5]  Laura M. Heiser,et al.  A central role for RAF→MEK→ERK signaling in the genesis of pancreatic ductal adenocarcinoma. , 2012, Cancer discovery.

[6]  C. Berking,et al.  Efficacy and safety of oral MEK162 in patients with locally advanced and unresectable or metastatic cutaneous melanoma harboring BRAFV600 or NRAS mutations. , 2012 .

[7]  A. Ribas,et al.  Antitumor effects of the investigational selective MEK inhibitor TAK733 against cutaneous and uveal melanoma cell lines , 2012, Molecular Cancer.

[8]  T. Gilmer,et al.  Combinations of BRAF, MEK, and PI3K/mTOR Inhibitors Overcome Acquired Resistance to the BRAF Inhibitor GSK2118436 Dabrafenib, Mediated by NRAS or MEK Mutations , 2012, Molecular Cancer Therapeutics.

[9]  F. Kelleher,et al.  Targeting NRAS in Melanoma , 2012, Cancer journal.

[10]  V. Guallar,et al.  Identification of dual mTORC1 and mTORC2 inhibitors in melanoma cells: prodigiosin vs. obatoclax. , 2012, Biochemical pharmacology.

[11]  B. Kholodenko,et al.  Cross-talk between mitogenic Ras/MAPK and survival PI3K/Akt pathways: a fine balance. , 2012, Biochemical Society transactions.

[12]  H. Temple,et al.  mTORC1 inhibition and ECM–cell adhesion-independent drug resistance via PI3K–AKT and PI3K–RAS–MAPK feedback loops , 2012, Tumor Biology.

[13]  P. Mischel,et al.  Reversing Melanoma Cross-Resistance to BRAF and MEK Inhibitors by Co-Targeting the AKT/mTOR Pathway , 2011, PloS one.

[14]  C. Tzen,et al.  Clinical outcome and pathological features associated with NRAS mutation in cutaneous melanoma , 2011, Pigment cell & melanoma research.

[15]  Rodney J Hicks,et al.  In Vivo Activity of Combined PI3K/mTOR and MEK Inhibition in a KrasG12D;Pten Deletion Mouse Model of Ovarian Cancer , 2011, Molecular Cancer Therapeutics.

[16]  Q. Mi,et al.  BRAF exon 15 T1799A mutation is common in melanocytic nevi, but less prevalent in cutaneous malignant melanoma, in Chinese Han. , 2011, The Journal of investigative dermatology.

[17]  C. Klemke,et al.  High-throughput mutation profiling of CTCL samples reveals KRAS and NRAS mutations sensitizing tumors toward inhibition of the RAS/RAF/MEK signaling cascade. , 2011, Blood.

[18]  Q. She,et al.  4E-BP1 is a key effector of the oncogenic activation of the AKT and ERK signaling pathways that integrates their function in tumors. , 2010, Cancer cell.

[19]  G. Merlino,et al.  Dissection of RAS downstream pathways in melanomagenesis: a role for Ral in transformation , 2010, Oncogene.

[20]  William Pao,et al.  Identifying genotype-dependent efficacy of single and combined PI3K- and MAPK-pathway inhibition in cancer , 2009, Proceedings of the National Academy of Sciences.

[21]  David P. Davis,et al.  Combined Targeting of BRAF and CRAF or BRAF and PI3K Effector Pathways Is Required for Efficacy in NRAS Mutant Tumors , 2009, PloS one.

[22]  P. Pandolfi,et al.  Inhibition of mTORC1 leads to MAPK pathway activation through a PI3K-dependent feedback loop in human cancer. , 2008, The Journal of clinical investigation.

[23]  G. Warren,et al.  Identification of 4-(2-(4-amino-1,2,5-oxadiazol-3-yl)-1-ethyl-7-{[(3S)-3-piperidinylmethyl]oxy}-1H-imidazo[4,5-c]pyridin-4-yl)-2-methyl-3-butyn-2-ol (GSK690693), a novel inhibitor of AKT kinase. , 2008, Journal of medicinal chemistry.

[24]  T. Hunter,et al.  Akt inhibitor A-443654 induces rapid Akt Ser-473 phosphorylation independent of mTORC1 inhibition , 2007, Oncogene.

[25]  Kevin Shannon,et al.  Targeting oncogenic Ras. , 2007, Genes & development.

[26]  Suzanne Schubbert,et al.  Hyperactive Ras in developmental disorders and cancer , 2007, Nature Reviews Cancer.

[27]  S. Cook.  Faculty Opinions recommendation of Binding of ras to phosphoinositide 3-kinase p110alpha is required for ras-driven tumorigenesis in mice. , 2007 .

[28]  G. Stamp,et al.  Binding of Ras to Phosphoinositide 3-Kinase p110α Is Required for Ras- Driven Tumorigenesis in Mice , 2007, Cell.

[29]  Ting-Chao Chou,et al.  Theoretical Basis, Experimental Design, and Computerized Simulation of Synergism and Antagonism in Drug Combination Studies , 2006, Pharmacological Reviews.

[30]  C. Niemeyer,et al.  Germline Mutations in Components of the Ras Signaling Pathway in Noonan Syndrome and Related Disorders , 2006, Cell cycle.

[31]  Todd R. Golub,et al.  BRAF mutation predicts sensitivity to MEK inhibition , 2006, Nature.

[32]  J. Fridlyand,et al.  Distinct sets of genetic alterations in melanoma. , 2005, The New England journal of medicine.

[33]  D. Ruiter,et al.  Analysis of Mutations in B-RAF, N-RAS, and H-RAS Genes in the Differential Diagnosis of Spitz Nevus and Spitzoid Melanoma , 2005, The American journal of surgical pathology.

[34]  J. Castro,et al.  Suppression of oncogenic NRAS by RNA interference induces apoptosis of human melanoma cells , 2005, International journal of cancer.

[35]  K. Giehl.  Oncogenic Ras in tumour progression and metastasis , 2005, Biological chemistry.

[36]  G. Reifenberger,et al.  Frequent alterations of Ras signaling pathway genes in sporadic malignant melanomas , 2004, International journal of cancer.

[37]  D. Barford,et al.  Mechanism of Activation of the RAF-ERK Signaling Pathway by Oncogenic Mutations of B-RAF , 2004, Cell.

[38]  L. Kanter,et al.  NRAS and BRAF mutations arise early during melanoma pathogenesis and are preserved throughout tumor progression. , 2003, Clinical cancer research : an official journal of the American Association for Cancer Research.

[39]  C. Begg,et al.  Phase III multicenter randomized trial of the Dartmouth regimen versus dacarbazine in patients with metastatic melanoma. , 1999, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[40]  J. Hoeffler,et al.  Ras mutations in human melanoma: a marker of malignant progression. , 1994, The Journal of investigative dermatology.

[41]  L. J. Veer,et al.  N-ras mutations in human cutaneous melanoma from sun-exposed body sites , 1989, Molecular and cellular biology.