CSAG1 maintains the integrity of the mitotic centrosome in cells with defective p53

Parallel and convergent dynamics in the evolution of primary breast and lung adenocarcinomas

Cancer development requires an evolutionary transformation from mammalian cells fully regulated by and integrated into multicellular tissue to cancer cells  that, as single cell protists, are individually subject to Darwinian selection. Through genetic and epigenetic mechanisms of inheritance, the evolving cancer phenotype must acquire independence from host controls, downregulate differentiated functions that benefit the host but not individual cells, and generate phenotypic traits that increase fitness in the context of the selection forces within the local microenvironment. Here, we investigate this  evolutionary transition in breast (BRCA) and lung (LUAD, without EGFR, KRAS or BRAF driver mutations) adenocarcinomas using bulk mutation and expression data from the TCGA database. We define evolution selection for genes and molecular pathways based on 1) changes in gene expression compared to normal tissue, and 2) significantly larger or smaller observed mutation rates compared to those expected based on the gene size. We find BRCA and LUAD disable different genes and gene pathways associated with tissue-specific signaling and differentiated functions but promote common molecular pathways associated with cell cycle, cell-cell interactions, cytoskeleton, voltage gated ion channels, and microenvironmental niche construction. Thus, tissue-specific parallel evolution in early cancer development is followed by convergence to a common cancer phenotype.

An integrative analysis of GEO data to identify possible therapeutic biomarkers of prostate cancer and targeting potential protein through Zea mays phytochemicals by virtual screening approaches

Prostate cancer (PC) is a prevalent type of cancer among men. Delaying the treatment of patients with upgraded or upstaged cancer may lead to unmanageable circumstances. The aim of this study is to contribute to the finding of biomarkers that are specific to PC and identify drug candidates derived from plants. The information about cancer is critical for clinicians to make decisions about patient treatment in the era of precision medicine. Advances in genomics technology have opened up new possibilities for identifying genes that are associated with cancer, including PC. This study identifies novel differentially expressed genes for PC. The seven PC microarray datasets were selected from the National Center for Biotechnology Information (NCBI)/Gene Expression Omnibus (GEO). The differentially expressed genes (DEGs) were found based on a fold change of |logFC| ≥ 1 and an adjusted p-value of <0.05. The DEGs were further studied using several bioinformatics tools, including STRING, CytoHubba, SRplot, Coremine Medical database, FunRich and GeneMANIA, cBioPortal. The six new potential biomarkers, GAGE2A, GAGE12G, GAGE2E, GAGE13, GAGE12F and CSAG1 were identified. These biomarkers are associated with biological processes (BPs) such as cell division, and gene expression regulation, so these genes may have a crucial role in PC progression and may serve as potential biomarkers for PC. A total of 497 phytochemicals from corn plants have been screened against the target protein and found LTS0176591 as the best lead molecule with docking score of -6.31 kcal/mol. Further, molecular mechanics-generalized born surface area (MM-GBSA), molecular dynamics simulation, principal component analysis (PCA), free energy landscape (FEL) and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) were carried out to validate the findings.Communicated by Ramaswamy H. Sarma.

Mate-pair genome sequencing reveals structural variants for idiopathic male infertility

Currently, routine genetic investigation for male infertility includes karyotyping analysis and PCR for Y chromosomal microdeletions to provide prognostic information such as sperm retrieval success rate. However, over 85% of male infertility remain idiopathic. We assessed 101 male patients with primary infertility in a retrospective cohort analysis who have previously received negative results from standard-of-care tests. Mate-pair genome sequencing (large-insert size library), an alternative long-DNA sequencing method, was performed to detect clinically significant structural variants (SVs) and copy-number neutral absence of heterozygosity (AOH). Candidate SVs were filtered against our in-house cohort of 1077 fertile men. Genes disrupted by potentially clinically significant variants were correlated with single-cell gene expression profiles of human fetal and postnatal testicular developmental lineages and adult germ cells. Follow-up studies were conducted for each patient with clinically relevant finding(s). Molecular diagnoses were made in 11.1% (7/63) of patients with non-obstructive azoospermia and 13.2% (5/38) of patients with severe oligozoospermia. Among them, 12 clinically significant SVs were identified in 12 cases, including five known syndromes, one inversion, and six SVs with direct disruption of genes by intragenic rearrangements or complex insertions. Importantly, a genetic defect related to intracytoplasmic sperm injection (ICSI) failure was identified in a patient with non-obstructive azoospermia, illustrating the additional value of an etiologic diagnosis in addition to determining sperm retrieval rate. Our study reveals a landscape of various genomic variants in 101 males with idiopathic infertility, not only advancing understanding of the underlying mechanisms of male infertility, but also impacting clinical management.

Identification of Cancer/Testis Antigens Related to Gastric Cancer Prognosis Based on Co-Expression Network and Integrated Transcriptome Analyses

Background

Gastric cancer is a worldwide life-threatening cancer. The underlying cause of it is still unknown. We have noticed that some cancer/testis antigens (CTAs) are up-regulated in gastric cancer. The role of these genes in gastric cancer development is not fully understood. The main aim of the current study was to comprehensively investigate CTAs' expression and function in stomach adenocarcinoma (STAD).

Materials and Methods

A comprehensive list of CTA genes was compiled from different databases. Transcriptome profiles of STAD were downloaded from the cancer genome atlas (TCGA) database and analyzed. Differentially-expressed CTAs were identified. Pathway enrichment analysis, weighted gene correlation network analysis (WGCNA), and overall survival (OS) analysis were performed on differentially-expressed CTA genes.

Results

Pathway enrichment analysis indicates that CTA genes are involved in protein binding, ribonucleic acid processing, and reproductive tissues. WGCNA showed that six differentially-expressed CTA genes, namely Melanoma antigen gene (MAGE) family member A3, A6, A12 and chondrosarcoma associated gene (CSAG) 1, 2, and 3, were correlated. Up-regulation of MAGEA11, MAGEC3, Per ARNT SIM domain containing 1 (PASD1), placenta-specific protein 1 (PLAC1) and sperm protein associated with the nucleus X-linked family member (SPANXB1) were significantly associated with lower OS of patients.

Conclusion

MAGEA11, MAGEC3, PASD1, PLAC1, and SPANXB1 can be investigated as prognostic biomarkers in basic and clinical studies. Further functional experiments are needed to understand the exact interaction mechanisms of these genes.

Differential gene expression and network analysis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignancy with a poor prognosis, whose biomarkers have not been studied in great detail. We have collected genomic data of HNSCC patients from The Cancer Genome Atlas (TCGA) and analyzed them to get deeper insights into the gene expression pattern. Initially, 793 differentially expressed genes (DEGs) were categorized, and their enrichment analysis was performed. Later, a protein-protein interaction network for the DEGs was constructed using the STRING plugin in Cytoscape to study their interactions. A set of 10 hub genes was selected based on Maximal Clique Centrality score, and later their survival analysis was studied. The elucidated set of 10 genes, i.e., PRAME, MAGEC2, MAGEA12, LHX1, MAGEA3, CSAG1, MAGEA6, LCE6A, LCE2D, LCE2C, referred to as potential candidates to be explored as HNSCC biomarkers. The Kaplan-Meier overall survival of the selected genes suggested that the alterations in the candidate genes were linked to the decreased survival of the HNSCC patients. Altogether, the results of this study signify that the genomic alterations and differential expression of the selected genes can be explored in therapeutic interpolations of HNSCC, exploiting early diagnosis and target-propelled therapy.

Keep Calm and Carry on with Extra Centrosomes

Simple Summary

Precise chromosome segregation during mitosis is a vital event orchestrated by formation of bipolar spindle poles. Supernumerary centrosomes, caused by centrosome amplification, deteriorates mitotic processes, resulting in segregation defects leading to chromosomal instability (CIN). Centrosome amplification is frequently observed in various types of cancer and considered as a significant contributor to destabilization of chromosomes. This review provides a comprehensive overview of causes and consequences of centrosome amplification thoroughly describing molecular mechanisms.

Abstract

Aberrations in the centrosome number and structure can readily be detected at all stages of tumor progression and are considered hallmarks of cancer. Centrosome anomalies are closely linked to chromosome instability and, therefore, are proposed to be one of the driving events of tumor formation and progression. This concept, first posited by Boveri over 100 years ago, has been an area of interest to cancer researchers. We have now begun to understand the processes by which these numerical and structural anomalies may lead to cancer, and vice-versa: how key events that occur during carcinogenesis could lead to amplification of centrosomes. Despite the proliferative advantages that having extra centrosomes may confer, their presence can also lead to loss of essential genetic material as a result of segregational errors and cancer cells must deal with these deadly consequences. Here, we review recent advances in the current literature describing the mechanisms by which cancer cells amplify their centrosomes and the methods they employ to tolerate the presence of these anomalies, focusing particularly on centrosomal clustering.

CSAG2 is a cancer-specific activator of SIRT1

SIRT1 is a NAD⁺ -dependent deacetylase that controls key metabolic and signaling pathways, including inactivating the p53 tumor suppressor. However, the mechanisms controlling SIRT1 enzymatic activity in the context of cancer are unclear. Here, we show that the previously undescribed CSAG2 protein is a direct activator of SIRT1. CSAG2 is normally restricted to expression in the male germline but is frequently re-activated in cancers. CSAG2 is necessary for cancer cell proliferation and promotes tumorigenesis in vivo. Biochemical studies revealed that CSAG2 directly binds to and stimulates SIRT1 activity toward multiple substrates. Importantly, CSAG2 enhances SIRT1-mediated deacetylation of p53, inhibits p53 transcriptional activity, and improves cell survival in response to genotoxic stress. Mechanistically, CSAG2 binds SIRT1 catalytic domain and promotes activity independent of altering substrate affinity. Together, our results identify a previously undescribed mechanism for SIRT1 activation in cancer cells and highlight unanticipated approaches to therapeutically modulate SIRT1.