ABSTRACT
OBJECTIVE: To investigate whether scorpion extract elicits a neuroprotective effect in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice models, and the genes associated with the therapeutic effects using RNA sequencing (seq) analysis. METHODS: This study investigated the changes in interaction between messenger ribonucleic acid (mRNA) expression and deoxyribonucleic acid (DNA) methylation related to the protective effects of scorpion extracts, in the substantia nigra (SN) region of a MPTP-induced Parkinson's disease (PD) model. RESULTS: In this model, scorpion extracts attenuated the motor impairment as demonstrated by the rotarod and open field tests. Scorpion extracts consistently attenuated the decrease of tyrosine hydroxylase (TH) positive neural cells in the SN and striatum of mice. We profiled genome- wide DNA methylation using Methyl-Seq and measured the transcriptome using RNA-Seq in murine SN in the following groups: vehicle-treated MPTP-induced PD mice and scorpion extract- treated MPTP-induced PD mice. In total, 13 479 differentially expressed genes were identified in association with the anti-PD effect of the scorpion extract, mainly in the promoter and coding regions. Among them, 47 were negatively correlated down- regulated genes. Nineteen genes out of 47 down- regulated genes were negatively correlated with the expression of the other 28 genes. Among these genes, SGSM1 was related to dopaminergic neu- rons including dopamine transporters, TH, dihy- droxyphenylalanine decarboxylase, and dopamine D2 receptor. CONCLUSION: This study provides insights into the anti-parkinsonian effects of scorpion extract and reveals the epigenetic targets in its therapeutic mechanism.
Subject(s)
Neuroprotective Agents , Parkinson Disease , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine , Animals , Disease Models, Animal , Epigenesis, Genetic , Mice , Mice, Inbred C57BL , Parkinson Disease/drug therapy , Parkinson Disease/genetics , ScorpionsABSTRACT
BACKGROUND: Resistance to HER2-targeted therapy with trastuzumab still remains a major challenge in HER2-amplified tumors. Here we investigated the potential role of MEL-18, a polycomb group gene, as a novel prognostic marker for trastuzumab resistance in HER2-positive (HER2+) breast cancer. METHODS: The genetic alteration of MEL-18 and its clinical relevance were examined in multiple breast cancer cohorts including METABRIC (n = 1,980), TCGA (n = 825), and our clinical specimens (n = 213, trastuzumab-treated HER2+ cases). MEL-18 amplification was validated by fluorescence in situ hybridization (FISH) analysis. The MEL-18 effect on trastuzumab response was confirmed by in vitro cell viability assays and an in vivo xenograft experiment (n = 7 per group). Gene expression microarray and receptor tyrosine kinase array were performed to identify the trastuzumab resistance mechanism by MEL-18 loss. All statistical tests were two-sided. RESULTS: MEL-18 was exclusively amplified in approximately 30-50% of HER2+ breast tumors and was associated with a favorable clinical outcome (disease-free survival: P = .02 in HER2+ cases, METABRIC; P = .04 in patients receiving trastuzumab). In MEL-18-amplified HER2+ breast cancer, MEL-18 depletion induced trastuzumab resistance by increasing ADAM sheddase-mediated ErbB ligand production and receptor heterodimerization. MEL-18 epigenetically silenced ADAM10/17 expression in cooperation with polycomb-repressive complex (PRC) 1 and PRC2. Combination treatment with an ADAM10/17 inhibitor and trastuzumab could overcome MEL-18 loss-mediated trastuzumab resistance in vivo (BT474/shMEL-18 xenograft: trastuzumab, mean [SD] tumor volume = 406.1 [50.1] mm3, vs trastuzumab + GW280264 30 mg/kg, mean [SD] tumor volume = 68.4 [15.6] mm3, P < .001). Consistently, trastuzumab-treated patients harboring concomitant MEL-18 amplification and low ADAM17 expression showed prolonged relapse-free survival (P = .02 in our cohort, n = 213). CONCLUSION: MEL-18 serves to prevent ligand-dependent ErbB heterodimerization and trastuzumab resistance, suggesting MEL-18 amplification as a novel biomarker for HER2+ breast cancer.