LY3009120, a panRAF inhibitor, has significant anti-tumor activity in BRAF and KRAS mutant preclinical models of colorectal cancer

Eliza Vakana; Susan Pratt; Wayne Blosser; Michele Dowless; Nicholas Simpson; Xiu-Juan Yuan; Susan Jaken; Jason Manro; Jennifer Stephens; Youyan Zhang; Lysiane Huber; Sheng-Bin Peng; Louis F Stancato

doi:10.18632/oncotarget.14002

LY3009120, a panRAF inhibitor, has significant anti-tumor activity in BRAF and KRAS mutant preclinical models of colorectal cancer

Oncotarget. 2017 Feb 7;8(6):9251-9266. doi: 10.18632/oncotarget.14002.

Authors

Affiliations

¹ Oncology Discovery Research, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
² Discovery Research, Advanced Testing Laboratory, Cincinnati, OH 45242, USA.
³ Cell Technologies, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
⁴ Discovery Statistics, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.

Abstract

Activating mutations in the KRAS and BRAF genes, leading to hyperactivation of the RAS/RAF/MAPK oncogenic signaling cascade, are common in patients with colorectal cancer (CRC). While selective BRAF inhibitors are efficacious in BRAFmut melanoma, they have limited efficacy in BRAFmut CRC patients. In a RASmut background, selective BRAF inhibitors are contraindicated due to paradoxical activation of the MAPK pathway through potentiation of CRAF kinase activity. A way to overcome such paradoxical activation is through concurrent inhibition of the kinase activity of both RAF isoforms. Here, we further examined the effects of LY3009120, a panRAF and RAF dimer inhibitor, in human models of CRC with various mutational backgrounds. We demonstrate that LY3009120 induced anti-proliferative effects in BRAFmut and KRASmut CRC cell lines through G1-cell cycle arrest. The anti-proliferative effects of LY3009120 in KRASmut CRC cell lines phenocopied molecular inhibition of RAF isoforms by simultaneous siRNA-mediated knockdown of ARAF, BRAF and CRAF. Additionally, LY3009120 displayed significant activity in in vivo BRAFmut and KRASmut CRC xenograft models. Examination of potential resistance to LY3009120 demonstrated RAF-independent ERK and AKT activation in the KRASmut CRC cell line HCT 116. These findings describe the preclinical activity of a panRAF inhibitor in a BRAFmut and KRASmut CRC setting.

Keywords: RAF; RAS; colorectal cancer; signaling pathways; xenograft models.

MeSH terms

Animals
Antineoplastic Agents / pharmacology*
Apoptosis / drug effects
Cell Proliferation / drug effects
Colorectal Neoplasms / drug therapy*
Colorectal Neoplasms / enzymology
Colorectal Neoplasms / genetics
Colorectal Neoplasms / pathology
Dose-Response Relationship, Drug
Extracellular Signal-Regulated MAP Kinases / metabolism
Female
G1 Phase Cell Cycle Checkpoints / drug effects
Genetic Predisposition to Disease
HCT116 Cells
HT29 Cells
Humans
Mutation*
Phenotype
Phenylurea Compounds / pharmacology*
Protein Kinase Inhibitors / pharmacology*
Proto-Oncogene Proteins A-raf / antagonists & inhibitors
Proto-Oncogene Proteins A-raf / genetics
Proto-Oncogene Proteins A-raf / metabolism
Proto-Oncogene Proteins B-raf / antagonists & inhibitors*
Proto-Oncogene Proteins B-raf / genetics*
Proto-Oncogene Proteins B-raf / metabolism
Proto-Oncogene Proteins c-akt / metabolism
Proto-Oncogene Proteins c-raf / antagonists & inhibitors
Proto-Oncogene Proteins c-raf / genetics
Proto-Oncogene Proteins c-raf / metabolism
Proto-Oncogene Proteins p21(ras) / genetics*
Pyrimidines / pharmacology*
RNA Interference
Rats, Nude
Time Factors
Transfection
Tumor Burden / drug effects

Substances

Antineoplastic Agents
KRAS protein, human
LY3009120
Phenylurea Compounds
Protein Kinase Inhibitors
Pyrimidines
BRAF protein, human
Proto-Oncogene Proteins A-raf
Proto-Oncogene Proteins B-raf
Proto-Oncogene Proteins c-akt
Proto-Oncogene Proteins c-raf
Extracellular Signal-Regulated MAP Kinases
Proto-Oncogene Proteins p21(ras)