ABSTRACT
MAPK inhibitors (MAPKi) remain an important component of the standard of care for metastatic melanoma. However, acquired resistance to these drugs limits their therapeutic benefit. Tumor cells can become refractory to MAPKi by reactivation of ERK. When this happens, tumors often become sensitive to drug withdrawal. This drug addiction phenotype results from the hyperactivation of the oncogenic pathway, a phenomenon commonly referred to as oncogene overdose. Several feedback mechanisms are involved in regulating ERK signaling. However, the genes that serve as gatekeepers of oncogene overdose in mutant melanoma remain unknown. Here, we demonstrate that depletion of the ERK phosphatase, DUSP4, leads to toxic levels of MAPK activation in both drug-naive and drug-resistant mutant melanoma cells. Importantly, ERK hyperactivation is associated with down-regulation of lineage-defining genes including MITF Our results offer an alternative therapeutic strategy to treat mutant melanoma patients with acquired MAPKi resistance and those unable to tolerate MAPKi.
Subject(s)
Melanoma , Proto-Oncogene Proteins B-raf , Cell Line, Tumor , Drug Resistance, Neoplasm/genetics , Dual-Specificity Phosphatases/genetics , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Humans , Melanoma/genetics , Melanoma/pathology , Membrane Proteins/metabolism , Microphthalmia-Associated Transcription Factor/genetics , Mitogen-Activated Protein Kinase Phosphatases/genetics , Oncogenes , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins B-raf/geneticsABSTRACT
BACKGROUND: Biomarker-based analyses are commonly reported in observational epidemiological studies; however currently there are no specific study quality assessment tools to assist evaluation of conducted research. Accounting for study design and biomarker measurement would be important for deriving valid conclusions when conducting systematic data evaluation. METHODS: We developed a study quality assessment tool designed specifically to assess biomarker-based cross-sectional studies (BIOCROSS) and evaluated its inter-rater reliability. The tool includes 10-items covering 5 domains: 'Study rational', 'Design/Methods', 'Data analysis', 'Data interpretation' and 'Biomarker measurement', aiming to assess different quality features of biomarker cross-sectional studies. To evaluate the inter-rater reliability, 30 studies were distributed among 5 raters and intraclass correlation coefficients (ICC-s) were derived from respective ratings. RESULTS: The estimated overall ICC between the 5 raters was 0.57 (95% Confidence Interval (CI): 0.38-0.74) indicating a good inter-rater reliability. The ICC-s ranged from 0.11 (95% CI: 0.01-0.27) for the domain 'Study rational' to 0.56 (95% CI: 0.40-0.72) for the domain 'Data interpretation'. CONCLUSION: BIOCROSS is a new study quality assessment tool suitable for evaluation of reporting quality from cross-sectional epidemiological studies employing biomarker data. The tool proved to be reliable for use by biomedical scientists with diverse backgrounds and could facilitate comprehensive review of biomarker studies in human research.
