RESUMEN
Objective:Cushing′s disease(CD) is caused by the pituitary adrenocorticotroph hormone(ACTH) secreting adenomas, leading to increased serum cortisol levels and various abnormal metabolic processes. Untreated CD is linked to high mortality, thus it is critical to elucidate its pathogenesis. This study aims to explore the pathogenesis of pituitary ACTH adenomas using whole-genome sequencing analysis.Methods:Fresh tumor tissues and peripheral blood samples were collected in 9 confirmed cases of pituitary ACTH adenomas who underwent surgery. Whole genome sequencing was then performed, followed by analysis and verification of single nucleotide mutations, copy number variation(CNV) and chromosome structure variations.Results:Somatic USP8 mutations(p.Ser718del, p. Ser718Pro, p. Pro720Arg, p. Pro720Gln) were found in 5 patients, with a rate of 55.6%; CNV of USP8 was detected in 1 patient; TP53(p.Cys135Tyr), NF1(p.Val1049Glufs*11) and KMT2C(c.3323+ 1G>A) mutations were identified in 1 patient harboring wild-type USP8. CNV analysis showed a loss of heterozygosity in multiple chromosomes in a wild-type USP8 patient. Structural variations were found in 2 with unknown significance. No germline gene mutations were detected in this study.Conclusion:Somatic USP8 mutations, increased copy number of USP8, variations of tumor-related genes such as TP53 and extensive somatic CNV all contribute to pathogenesis of CD. Chromosomal structure variations may suggest high-risk pituitary ACTH adenomas, and call for frequent follow-up and aggressive treatment.
RESUMEN
BACKGROUND: Therapeutic approach by treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) like gefitinib or erlotinib to non-small cell lung cancer (NSCLC) patients has been limited due to emergence of acquired drug resistance. Our study was aimed to investigate whether the inhibition of ubiquitin-specific peptidase 8 (USP8) could be an alternative strategy capable of overcoming acquired resistance to EGFR-TKIs for treatment of NSCLCs. METHODS: The anticancer effect of USP8 inhibitor was determined by testing anchorage-dependent or independent growth of gefitinib-sensitive or resistant NSCLCs. The immunoprecipitation and western blotting were conducted to check molecular interaction and signaling pathway followed by USP8 inhibition. RESULTS: Inhibition of USP8 induced overall degradation of oncogenic receptor tyrosine kinases including EGFR and Met, leading to a suppression of anchorage-dependent or independent cell growth of gefitinib-sensitive or resistant NSCLCs. Also, treatment with the USP8 inhibitor markedly induced apoptosis in HCC827GR cells. Notably, treatment with the USP8 inhibitor was more effective in suppressing cell growth and inducing apoptosis in gefitinib-resistant HCC827GR cells than that of gefitinib-sensitive HCC827 cells. CONCLUSIONS: Inhibition of USP8 could be an effective strategy for overcoming gefitinib resistance in NSCLCs.