Novel in-frame duplication variant characterization in late infantile metachromatic leukodystrophy using whole-exome sequencing and molecular dynamics simulation.

Metachromatic leukodystrophy (MLD) is a neurodegenerative lysosomal storage disease caused by a deficiency in the arylsulfatase A (ARSA). ARSA deficiency leads to sulfatide accumulation, which involves progressive demyelination. The profound impact of early diagnosis on MLD treatment options necessitates the development of new or updated analysis tools and approaches. In this study, to identify the genetic etiology in a proband from a consanguineous family with MLD presentation and low ARSA activity, we employed Whole-Exome Sequencing (WES) followed by co-segregation analysis using Sanger sequencing. Also, MD simulation was utilized to study how the variant alters the structural behavior and function of the ARSA protein. GROMACS was applied and the data was analyzed by RMSD, RMSF, Rg, SASA, HB, atomic distance, PCA, and FEL. Variant interpretation was done based on the American College of Medical Genetics and Genomics (ACMG) guidelines. WES results showed a novel homozygous insertion mutation, c.109_126dup (p.Asp37_Gly42dup), in the ARSA gene. This variant is located in the first exon of ARSA, fulfilling the criteria of being categorized as likely pathogenic, according to the ACMG guidelines and it was also found to be co-segregating in the family. The MD simulation analysis revealed this mutation influenced the structure and the stabilization of ARSA and led to the protein function impairment. Here, we report a useful application of WES and MD to identify the causes of a neurometabolic disorder.

Design, synthesis, and cytotoxicity evaluation of novel indole-acylhydrazone derivatives of 4-pyridinone as potential histone deacetylase-2 inhibitors.

Background and purpose: Histone deacetylation is one of the essential cellular pathways in the growth and spread of cancer, so the design of histone deacetylase (HDAC) inhibitors as anticancer agents is of great importance in pharmaceutical chemistry. Here, a series of indole acylhydrazone derivatives of 4-pyridone have been introduced as potential histone deacetylase inhibitors. Experimental approach: Seven indole-acylhydrazone-pyridinone derivatives were synthesized via simple, straightforward chemical procedures. The molecular docking studies were accomplished on HDAC2 compared to panobinostat. The cytotoxicity of all derivatives was studied on MCF-7 and MDA-MB-231 breast cancer cell lines by MTT assay. Findings / Results: Molecular docking studies supported excellent fitting to the HADC2 active site with binding energies in the range of -10 Kcal/mol for all derivatives. All compounds were tested for their cytotoxicity against MCF-7 and MDA-MB-231 cell lines; derivatives A, B, F, and G were the best candidates. The half-maximal inhibitory concentration (IC50) values on MCF-7 were below 25 mg/mL and much lower than those obtained on the MDA-MB-231 cell line. Conclusion and implications: The derivatives showed selectivity toward the MCF-7 cell line, probably due to the higher HDAC expression in the MCF-7 cell line. In this regard, debenzylated derivatives F and G showed slightly better cytotoxicity, which should be more studied in the future. Derivatives A, B, F, and G were promising for future enzymatic studies.

Structure-based inhibitory peptide design targeting peptide-substrate binding site in EGFR tyrosine kinase.

EGFR (epidermal growth factor receptor) plays the critical roles in the vital cell activities, proliferation, differentiation, migration and survival in response to polypeptide growth factor ligands. Aberrant activation of this receptor has been demonstrated in many human cancers, particularly in non-small cell lung carcinoma (NSCLC). L858R point mutation is the most common oncogenic mutation in EGFR tyrosine kinase domain in patients with EGFR-mutated NSCLC. A feedback inhibitor of EGFR is MIG6 molecule which binds peptide-substrate binding site of the receptor and leads to degradation of activated EGFR. In this in silico study, the peptide-substrate binding site of EGFRL858R mutant has been targeted to inhibit it using molecular docking, MD simulation and MM-PBSA method. Finally, physicochemical properties of the designed peptides have been evaluated. A peptide library was provided composed of 31 peptides which were designed based on the MIG6 structure. The results indicated that, two peptides were able to inhibit EGFRL858R mutant selectively. This computational study could be helpful in designing novel inhibitory peptides to inhibit oncogenic EGFR mutants which do not respond to available EGFR TKIs.