plx4032 and Colorectal-Neoplasms

Epidermal growth factor receptor (EGFR) amplification has been demonstrated to be critical for the inherent and/or acquired resistance against current B-Raf(V600E) inhibitor therapy for melanoma and colorectal cancer patients. We describe the discovery and structure-activity relationship study of a series of 1H-pyrazolo[3,4-b]pyridine-5-carboxamide analogues as novel dual inhibitors of EGFR and B-Raf(V600E) mutant. One of the most promising compounds, 6a, potently inhibited both of the kinases with IC50 values of 8.0 and 51 nM, respectively. The compound also strongly suppressed the proliferation of a panel of intrinsic and acquired resistant melanoma and/or colorectal cancer cells harboring overexpressed EGFR with submicromolar IC50 values. Further mechanism investigation revealed that 6a could sustainably inhibit the activation of the MAPK path way in the resistant SK-MEL-28 PR30 melanoma cancer cells and WiDr colorectal cancer cells with EGFR amplification. Our results support the hypothesis that the EGFR/B-Raf(V600E) dual inhibition might be a tractable strategy to overcome the intrinsic and acquired resistance of melanoma and/or colorectal cancers against the current B-Raf(V600E) inhibitor therapy.

Topics: Blotting, Western; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Drug Evaluation, Preclinical; Drug Resistance, Neoplasm; ErbB Receptors; Genes, erbB-1; Humans; Indicators and Reagents; Indoles; Melanoma; Mitogen-Activated Protein Kinases; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Structure-Activity Relationship; Sulfonamides; Vemurafenib