Centromere Protein A Goes Far Beyond the Centromere in Cancers

Multifunctional histone variants in genome function

Histones are integral components of eukaryotic chromatin that have a pivotal role in the organization and function of the genome. The dynamic regulation of chromatin involves the incorporation of histone variants, which can dramatically alter its structural and functional properties. Contrary to an earlier view that limited individual histone variants to specific genomic functions, new insights have revealed that histone variants exert multifaceted roles involving all aspects of genome function, from governing patterns of gene expression at precise genomic loci to participating in genome replication, repair and maintenance. This conceptual change has led to a new understanding of the intricate interplay between chromatin and DNA-dependent processes and how this connection translates into normal and abnormal cellular functions.

Knockdown of CENPM activates cGAS-STING pathway to inhibit ovarian cancer by promoting pyroptosis

OBJECTIVE

We aimed to screen novel gene signatures for ovarian cancer (OC) and explore the role of biomarkers in OC via regulating pyroptosis using bioinformatics analysis.

METHODS

Differentially expressed genes (DEGs) of OC were screened from GSE12470 and GSE16709 datasets. Hub genes were determined from protein-protein interaction networks after bioinformatics analysis. The role of Centromeric protein M (CENPM) in OC was assessed by subcutaneous tumor experiment using hematoxylin-eosin and immunohistochemical staining. Tumor metastasis was evaluated by detecting epithelial-mesenchymal transition-related proteins. The proliferation, migration, and invasion were determined using cell counting kit and transwell assay. Enzyme-linked immunosorbent assay was applied to measure inflammatory factors. The mRNA and protein expression were detected using real-time quantitative PCR and western blot.

RESULTS

We determined 9 hub genes (KIFC1, PCLAF, CDCA5, KNTC1, MCM3, OIP5, CENPM, KIF15, and ASF1B) with high prediction value for OC. In SKOV3 and A2780 cells, the expression levels of hub genes were significantly up-regulated, compared with normal ovarian cells. CENPM was selected as a key gene. Knockdown of CENPM suppressed proliferation, migration, and invasion of OC cells. Subcutaneous tumor experiment revealed that CENPM knockdown significantly suppressed tumor growth and metastasis. Additionally, pyroptosis was promoted in OC cells and xenograft tumors after CENPM knockdown. Furthermore, CENPM knockdown activated cGAS-STING pathway and the pathway inhibitor reversed the inhibitory effect of CENPM knockdown on viability, migration, and invasion of OC cells.

CONCLUSION

CENPM was a novel biomarker of OC, and knockdown of CENPM inhibited OC progression by promoting pyroptosis and activating cGAS-STING pathway.

Prognostic and immune infiltrative biomarkers of CENPO in pan-cancer and its relationship with lung adenocarcinoma cell proliferation and metastasis

BACKGROUND

The centromere protein O (CENPO) is an important member of the centromere protein family. However, the role of CENPO in pan-cancer and immune infiltration has not been reported. Here, we investigated the role of CENPO in pan-cancer and further validated its role in lung adenocarcinoma (LUAD) by in vitro experiments.

METHOD

The UCSC Xena database and The Cancer Genome Atlas (TCGA)-LUAD data were used to assess the expression levels of CENPO. The potential value of CENPO as a diagnostic and prognostic biomarker for pan-cancer was evaluated using TCGA data and the GEPIA database. The -expression profiles of LUAD patients and the corresponding clinical data were downloaded for correlation analysis. The role of CENPO in immune infiltration was investigated using the UCSC Xena database. Subsequently, qRT-PCR was performed to detect the expression of CENPO. Cell proliferation, migration, and invasion were determined using CCK-8, wound-healing assay, and transwell assay, respectively.

RESULTS

CENPO is highly expressed in most cancers, and the upregulation of CENPO is associated with poor prognosis in many cancers. CENPO expression correlates with age, TNM stage, N stage, T stage, and receipt of radiotherapy in LUAD patients, and LUAD patients with high CENPO expression have poorer overall survival (OS) and disease-free survival (DFS). In addition, CENPO expression is associated with immune cell infiltration and immune checkpoint inhibitors. Moreover, the expression of CENPO was closely related to the expression of tumor mutational load and microsatellite instability. In vitro experiments showed that CENPO expression was increased in LUAD cell lines and that knockdown of CENPO significantly inhibited the proliferation, cell invasion, and migration ability of LUAD cells.

CONCLUSION

CENPO may be a potential pan-cancer biomarker and oncogene, especially in LUAD. In addition, CENPO is associated with immune cell infiltration and may serve as a new molecular therapeutic target and effective prognostic marker for LUAD.

The role of tripartite motif-containing 28 in cancer progression and its therapeutic potentials

Tripartite motif-containing 28 (TRIM28) belongs to tripartite motif (TRIM) family. TRIM28 not only binds and degrades its downstream target, but also acts as a transcription co-factor to inhibit gene expression. More and more studies have shown that TRIM28 plays a vital role in tumor genesis and progression. Here, we reviewed the role of TRIM28 in tumor proliferation, migration, invasion and cell death. Moreover, we also summarized the important role of TRIM28 in tumor stemness sustainability and immune regulation. Because of the importance of TRIM28 in tumors, TIRM28 may be a candidate target for anti-tumor therapy and play an important role in tumor diagnosis and treatment in the future.

A risk signature based on necroptotic-process-related genes predicts prognosis and immune therapy response in kidney cell carcinoma

Necroptosis is a regulated form of cell necroptotic process, playing a pivotal role in tumors. In renal cell cancer (RCC), inhibiting necroptosis could promote the proliferation of tumor cells. However, the molecular mechanisms and prognosis prediction of necroptotic-process-related genes in RCC are still unclear. In this study, we first identified the necroptotic process prognosis-related genes (NPRGss) by analyzing the kidney renal clear cell carcinoma (KIRC) data in The Cancer Genome Atlas (TCGA, n=607). We systematically analyzed the expression alteration, clinical relevance, and molecular mechanisms of NPRGss in renal clear cell carcinoma. We constructed an NPRGs risk signature utilizing the least absolute shrinkage and selection operator (LASSO) Cox regression analysis on the basis of the expression of seven NPRGss. We discovered that the overall survival (OS) of KIRC patients differed significantly in high- or low-NPRGs-risk groups. The univariate/multivariate Cox regression revealed that the NPRGs risk signature was an independent prognosis factor in RCC. The gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were used to explore the molecular mechanisms of NPRGss. Immune-/metabolism-related pathways showed differential enrichment in high-/low-NPRGs-risk groups. The E-MTAB-1980, TCGA-KIRP, GSE78220, the cohort of Alexandra et al., and IMvigor210 cohort datasets were respectively used as independent validation cohorts of NPRGs risk signature. The patients in high- or low-NPRGs-risk groups showed different drug sensitivity, immune checkpoint expression, and immune therapy response. Finally, we established a nomogram based on the NPRGs risk signature, stage, grade, and age for eventual clinical translation; the nomogram possesses an accurate and stable prediction effect. The signature could predict patients’ prognosis and therapy response, which provides the foundation for further clinical therapeutic strategies for RCC patients.

The centromeric histone CenH3 is recruited into the tombusvirus replication organelles

Tombusviruses, similar to other (+)RNA viruses, exploit the host cells by co-opting numerous host components and rewiring cellular pathways to build extensive virus-induced replication organelles (VROs) in the cytosol of the infected cells. Most molecular resources are suboptimal in susceptible cells and therefore, tomato bushy stunt virus (TBSV) drives intensive remodeling and subversion of many cellular processes. The authors discovered that the nuclear centromeric CenH3 histone variant (Cse4p in yeast, CENP-A in humans) plays a major role in tombusvirus replication in plants and in the yeast model host. We find that over-expression of CenH3 greatly interferes with tombusvirus replication, whereas mutation or knockdown of CenH3 enhances TBSV replication in yeast and plants. CenH3 binds to the viral RNA and acts as an RNA chaperone. Although these data support a restriction role of CenH3 in tombusvirus replication, we demonstrate that by partially sequestering CenH3 into VROs, TBSV indirectly alters selective gene expression of the host, leading to more abundant protein pool. This in turn helps TBSV to subvert pro-viral host factors into replication. We show this through the example of hypoxia factors, glycolytic and fermentation enzymes, which are exploited more efficiently by tombusviruses to produce abundant ATP locally within the VROs in infected cells. Altogether, we propose that subversion of CenH3/Cse4p from the nucleus into cytosolic VROs facilitates transcriptional changes in the cells, which ultimately leads to more efficient ATP generation in situ within VROs by the co-opted glycolytic enzymes to support the energy requirement of virus replication. In summary, CenH3 plays both pro-viral and restriction functions during tombusvirus replication. This is a surprising novel role for a nuclear histone variant in cytosolic RNA virus replication.