Coexpression Network Analysis of Genes Related to the Characteristics of Tumor Stemness in Triple-Negative Breast Cancer
BIOMED RESEARCH INTERNATIONAL
Authors: Suo, Huan-dan; Tao, Zuo; Zhang, Lei; Jin, Zi-ning; Li, Xiao-ying; Ma, Wei; Wang, Zhen; Qiu, Yue; Jin, Feng; Chen, Bo; Cao, Yu
Abstract
Cancer stem cells (CSCs) are subsets of cells with the ability of self-renewal and differentiation in neoplasm, which are considered to be related to tumor heterogeneity. It has been reported that CSCs act on tumorigenesis and tumor biology of triple-negative breast cancer (TNBC). However, the key genes that cause TNBC showing stem cell characteristics are still unclear. We combined the RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA) database and mRNA expression-based stemness index (mRNAsi) to further analyze mRNAsi with regard to molecular subtypes, tumor depth, and pathological staging characteristics of breast cancer (BC). Secondly, we extract the differential gene expression of tumor vs. normal group and TNBC vs. other subtypes of BC group, respectively, and intersect them to achieve precise results. We used a weighted gene coexpression network analysis (WGCNA) to screen significant gene modules and the functions of selected genes including BIRC5, CDC25A, KIF18B, KIF2C, ORC1, RAD54L, and TPX2 were carried out through gene ontology (GO) functional annotation. The Oncomine, bc-GenExMiner v4.4, GeneMANIA, Kaplan-Meier Plotter (KM-plotter), and GEPIA were used to verify the expression level and functions of key genes. In this study, we found that TNBC had the highest stem cell characteristics in BC compared with other subtypes. The lower the mRNAsi score, the better the overall survival and treatment outcome. Seven key genes of TNBC were screened and functional annotation indicated that there were strong correlations between them, relating to nuclear division, organelle fission, mitotic nuclear division, and other events that determine cell fate. Among these genes, we found four genes that were highly associated with adverse survival events. Seven key genes identified in this study were found to be closely related to the maintenance of TNBC stemness, and the overexpression of four showed earlier recurrence. The overall survival (OS) curves of all key genes between differential expression level crossed at around nine-year follow-up, which was consistent with the trend of the OS curve related to mRNAsi. These findings may provide new ideas for screening therapeutic targets in order to depress TNBC stemness.
USP8 mutations in corticotroph adenomas determine a distinct gene expression profile irrespective of functional tumour status
EUROPEAN JOURNAL OF ENDOCRINOLOGY
Authors: Bujko, Mateusz; Kober, Paulina; Boresowicz, Joanna; Rusetska, Natalia; Paziewska, Agnieszka; Dabrowska, Michalina; Piascik, Agata; Pekul, Monika; Zielinski, Grzegorz; Kunicki, Jacek; Bonicki, Wieslaw; Ostrowski, Jerzy; Siedlecki, Janusz A.; Maksymowicz, Maria
Abstract
Objective: Pituitary corticotroph adenomas commonly cause Cushing's disease (CD) but part of these tumours are hormonally inactive (silent corticotroph adenomas, SCA). USP8 mutations are well-known driver mutations in corticotrophinomas. Differences in transcriptomic profiles between functioning and silent tumours or tumours with different USP8 status have not been investigated. Design and methods: Forty-eight patients (28 CD, 20 SCA) were screened for USP8 mutations with Sanger sequencing. Twenty-four patients were included in transcriptomic profiling with Ampliseq Transcriptome Human Gene Expression Core Panel. The entire patients group was included in qRT-PCR analysis of selected genes expression. Immunohistochemistry was used for visualization of selected protein. Results: We found USP8 mutation in 15 patients with CD and 4 SCAs. USP8 mutations determine molecular profile of the tumours as showed by hierarchical clustering and identification of 1648 genes differentially expressed in USP8-mutated and USP8-wild-type tumours. Mutations affect many molecular pathways as observed in Gene Set Enrichment analysis. USP8-mutated adenomas showed higher level of POMC, CDC25A, MAPK4 but lower level of CCND2, CDK6, CDKN1B than USP8-wt tumours. Eighty-seven genes differentially expressed between CD-related adenomas and SCAs were found, including those involved in cell signalling (GLI2, DLC1, TBX2, RASSF6), cell adhesion (GJA1, CDH6), ion transport (KCNN4, KCNJ5) and GABA signalling (GABBR2, GABRD). Conclusion: USP8 mutations occur in functioning and silent corticotrophinomas. They have pleiotropic effect, not limited to EGFR signalling, and affect expression levels of many genes involved in different pathways. Expression of GABA-related genes GABBR2, GNAL, GABARD and KCNJ5 correspond to functional status of the tumours.