Comprehensive Analysis of Prognostic Value and Immune Infiltration of Chromobox Family Members in Colorectal Cancer

Current data and future perspectives on DNA methylation in ovarian cancer (Review)

Ovarian cancer (OC) represents the most prevalent malignancy of the female reproductive system. Its distinguishing features include a high aggressiveness, substantial morbidity and mortality, and a lack of apparent symptoms, which collectively pose significant challenges for early detection. Given that aberrant DNA methylation events leading to altered gene expression are characteristic of numerous tumor types, there has been extensive research into epigenetic mechanisms, particularly DNA methylation, in human cancers. In the context of OC, DNA methylation is often associated with the regulation of critical genes, such as BRCA1/2 and Ras‑association domain family 1A. Methylation modifications within the promoter regions of these genes not only contribute to the pathogenesis of OC, but also induce medication resistance and influence the prognosis of patients with OC. As such, a more in‑depth understanding of DNA methylation underpinning carcinogenesis could potentially facilitate the development of more effective therapeutic approaches for this intricate disease. The present review focuses on classical tumor suppressor genes, oncogenes, signaling pathways and associated microRNAs in an aim to elucidate the influence of DNA methylation on the development and progression of OC. The advantages and limitations of employing DNA methylation in the diagnosis, treatment and prevention of OC are also discussed. On the whole, the present literature review indicates that the DNA methylation of specific genes could potentially serve as a prognostic biomarker for OC and a therapeutic target for personalized treatment strategies. Further investigations in this field may yield more efficacious diagnostic and therapeutic alternatives for patients with OC.

Evaluating the Role of Neddylation Modifications in Kidney Renal Clear Cell Carcinoma: An Integrated Approach Using Bioinformatics, MLN4924 Dosing Experiments, and RNA Sequencing

BACKGROUND

Neddylation, a post-translational modification process, plays a crucial role in various human neoplasms. However, its connection with kidney renal clear cell carcinoma (KIRC) remains under-researched.

METHODS

We validated the Gene Set Cancer Analysis Lite (GSCALite) platform against The Cancer Genome Atlas (TCGA) database, analyzing 33 cancer types and their link with 17 neddylation-related genes. This included examining copy number variations (CNVs), single nucleotide variations (SNVs), mRNA expression, cellular pathway involvement, and methylation. Using Gene Set Variation Analysis (GSVA), we categorized these genes into three clusters and examined their impact on KIRC patient prognosis, drug responses, immune infiltration, and oncogenic pathways. Afterward, our objective is to identify genes that exhibit overexpression in KIRC and are associated with an adverse prognosis. After pinpointing the specific target gene, we used the specific inhibitor MLN4924 to inhibit the neddylation pathway to conduct RNA sequencing and related in vitro experiments to verify and study the specificity and potential mechanisms related to the target. This approach is geared towards enhancing our understanding of the prognostic importance of neddylation modification in KIRC.

RESULTS

We identified significant CNV, SNV, and methylation events in neddylation-related genes across various cancers, with notably higher expression levels observed in KIRC. Cluster analysis revealed a potential trade-off in the interactions among neddylation-related genes, where both high and low levels of gene expression are linked to adverse prognoses. This association is particularly pronounced concerning lymph node involvement, T stage classification, and Fustat score. Simultaneously, our research discovered that PSMB10 exhibits overexpression in KIRC when compared to normal tissues, negatively impacting patient prognosis. Through RNA sequencing and in vitro assays, we confirmed that the inhibition of neddylation modification could play a role in the regulation of various signaling pathways, thereby influencing the prognosis of KIRC. Moreover, our results underscore PSMB10 as a viable target for therapeutic intervention in KIRC, opening up novel pathways for the development of targeted treatment strategies.

CONCLUSION

This study underscores the regulatory function and potential mechanism of neddylation modification on the phenotype of KIRC, identifying PSMB10 as a key regulatory target with a significant role in influencing the prognosis of KIRC.

Whole transcriptome sequencing identifies a competitive endogenous RNA network that regulates the immunity of bladder cancer

Several types of non-coding RNAs such as circRNAs, lncRNAs, and miRNAs have been identified to regulate mRNAs through the mechanism known as the competitive endogenous RNA (ceRNA) network. To explore the role of the ceRNA regulatory network in the immune microenvironment of bladder cancer, whole-transcriptome sequencing of bladder tumor and its peritumoral tissues from 38 bladder cancer patients, with a total of 63 samples, was performed to screen differentially expressed circ-, lnc-, mi-, and mRNAs to construct a circ/lnc-mi-mRNA regulatory network with pruning algorithms. We excavated a key immune-related gene BDNF to build the final ceRNA network as hsa-miR-107 sponged by hsa-circ-000211, AC108488.1, and LINC00163. Finally, a meta-analysis of 7 public datasets demonstrated that low expression of BDNF and high expression of hsa-miR-107 were associated with longer survival. Our study identified a ceRNA regulatory network as a potentially new prognostic marker and molecular therapeutic target of bladder cancer.

CBX3 antagonizes IFNγ/STAT1/PD-L1 axis to modulate colon inflammation and CRC chemosensitivity

As an important immune stimulator and modulator, IFNγ is crucial for gut homeostasis and its dysregulation links to diverse colon pathologies, such as colitis and colorectal cancer (CRC). Here, we demonstrated that the epigenetic regulator, CBX3 (also known as HP1γ) antagonizes IFNγ signaling in the colon epithelium by transcriptionally repressing two critical IFNγ-responsive genes: STAT1 and CD274 (encoding Programmed death-ligand 1, PD-L1). Accordingly, CBX3 deletion resulted in chronic mouse colon inflammation, accompanied by upregulated STAT1 and CD274 expressions. Chromatin immunoprecipitation indicated that CBX3 tethers to STAT1 and CD274 promoters to inhibit their expression. Reversely, IFNγ significantly reduces CBX3 binding to these promoters and primes gene expression. This antagonist effect between CBX3 and IFNγ on STAT1/PD-L1 expression was also observed in CRC. Strikingly, CBX3 deletion heightened CRC cells sensitivity to IFNγ, which ultimately enhanced their chemosensitivity under IFNγ stimulation in vitro with CRC cells and in vivo with a syngeneic mouse tumor model. Overall, this work reveals that by negatively tuning IFNγ-stimulated immune genes' transcription, CBX3 participates in modulating colon inflammatory response and CRC chemo-resistance.

Subcellular expression pattern and clinical significance of CBX2 and CBX7 in breast cancer subtypes

Chromobox (CBX)2 and CBX7, members of CBX family protein, show diverse expression patterns and contrasting roles in certain cancers. We aimed to investigate the subcellular expression patterns and clinical significances of CBXs in breast cancer (BC) subtypes, which have heterogeneous clinical course and therapeutic responses. Among the subtypes, the triple-negative BC (TNBC) is a heterogeneous group that lacks specific markers. We categorized TNBC into quadruple-negative BC (QNBC) and TNBC, based on androgen receptor (AR) status, to make the groups more homogeneous. Immunohistochemistry for CBX proteins was performed on 323 primary invasive BC tissues and their clinical significances were analyzed. Cytoplasmic CBX2 (CBX2-c) was linked to adverse clinicopathological factors and TNBC and QNBC subtypes. In contrast, nuclear CBX7 (CBX7-n) was associated with favorable parameters and luminal A subtype. CBX2-c expression increased progressively from that in benign lesions to that in in situ carcinomas and invasive cancers, whereas CBX7-n and AR expressions showed sequential downregulation. AR was lower in metastatic tissues compared to matched primary cancer tissues. We speculate that the upregulation of CBX2-c and downregulation of CBX7-n could play a role in breast oncogenesis and an adverse clinical course, suggesting them as potential prognostic markers and therapeutic targets in invasive BCs.

APOB is a potential prognostic biomarker in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is significantly associated with adverse prognostic outcomes. The development and progression of different types of human tumors are significantly influenced by APOB. Nevertheless, the significance and pathomechanisms of APOB in HCC have not been conclusively determined. We assessed APOB expression levels in HCC using three publicly available databases of TIMER2.0, UALCAN and Human Protein Atlas. To identify the biological function of APOB, we conducted enrichment analysis via LinkedOmics. Moreover, UALCAN was employed to assess the relationship between APOB expression and clinicopathological features among HCC patients. Additionally, the Kaplan-Meier plotter was utilized to investigate the prognostic relevance of APOB in HCC. To explore potential regulatory ncRNAs that could bind to APOB, we utilized StarBase and GEPIA. Furthermore, the correlation between APOB expression and immune cell infiltration, as well as immune checkpoint genes, was investigated using Spearman's correlation analysis in TISIDB, GEPIA, and TIMER2.0. The findings of our investigation showed a notable decrease in the expression levels of APOB among individuals diagnosed with HCC. Moreover, a noteworthy correlation was observed between the expression of APOB and immune checkpoint genes, alongside the occurrence of immune cell infiltration. The levels of APOB expression in HCC tissues also showed correlations with various clinicopathological features. According to Cox regression analysis, decreased APOB expression emerged as a potential autonomous predictor for OS, RFS, DSS, and PFS among HCC patients. Furthermore, we identified six potential pathways associated with non-coding RNA (ncRNA) as the most promising pathway for APOB in HCC. Our results illuminate the possible involvement of APOB in HCC and offer understanding into its governing mechanisms and medical importance.

Predictive Values of Homeobox Gene A-Antisense Transcript 3 (HOXA-AS3), Cystatin 6 (CST6), and Chromobox Homolog 4 (CBX4) Expressions in Cancer Tissues for Recurrence of Early Colon Cancer After Surgery

Purpose

We aim to explore the predictive values of homeobox gene A-antisense transcript 3 (HOXA-AS3), cystatin 6 (CST6), and chromobox homolog 4 (CBX4) expressions in cancer tissues for the recurrence of early colon cancer after surgery.

Patients and Methods

A total of 136 patients who received surgery from January 2020 to January 2021 were enrolled and followed up for 24 months to observe the recurrence after surgery, based on which they were assigned into recurrence and non-recurrence groups. All patients underwent a histopathological examination on admission.

Results

The recurrence group had a lower degree of differentiation as well as a higher HOXA-AS3 level and CST6 and CBX4 expression scores than those of the non-recurrence group (P<0.05). HOXA-AS3 level, CST6 expression score, and CBX4 expression score were risk factors for the recurrence of early colon cancer after surgery [odds ratio (OR)>1, P<0.05]. The receiver operating characteristic curve analysis showed that the areas under the curves of HOXA-AS3 level, CST6 expression score, CBX4 expression score, and their combination for predicting recurrence were 0.909 [95% confidence interval (95% CI): 0.785-1.000], 0.819 (95% CI: 0.690-0.948), 0.794 (95% CI: 0.663-0.926), and 0.942 (95% CI: 0.882-1.000), respectively.

Conclusion

The expressions of HOXA-AS3, CST6, and CBX4 in cancer tissues have close correlations with the recurrence of early colon cancer after surgery and are thus of high predictive values.

A model for predicting clinical prognosis based on brain metastasis-related genes in patients with breast cancer

Background

Brain metastasis (BM) is a clinically relevant cause of death in patients with breast cancer (BRCA). This study was designed to develop a clinical model capable of predicting BRCA patients' prognostic outcomes according to the expression of BM-related genes (BMRGs).

Methods

The public Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases served as data sources. BMRGs of BRCA were selected from previous literature. Differences among BRCA molecular subtypes were compared using R 'limma' package. The impact of BM-related differentially expressed genes (BM_DEGs) on BRCA patients' outcomes was explored with a risk score model, after which the relationship between these risk scores and immune cell infiltration was examined. Risk scores were also used to judge the predicted efficacy of immunotherapeutic interventions. The utility of risk scores in combination with clinicopathological characteristics was evaluated as a predictor of patient's survival through univariate and multivariate analyses.

Results

The R limma package was used to explore differential gene expression, after which 12 BM_DEGs were incorporated into a risk scoring model. The resultant risk scores were able to predict immunotherapeutic treatment efficacy. In addition, a nomogram incorporating risk scores, stage, and age was established. The nomogram was able to reliably predict the overall survival (OS) of BRCA patients, yielding predictive outcomes that aligned well with actual observations.

Conclusions

In summary, a predictive clinical model for BRCA patients was successfully established in this study, providing a valuable tool that may be particularly helpful for the assessment of patients facing a risk of BM development.

Circ-NUP98 Promotes Lung Adenocarcinoma Development Through Regulating CBX1 by miR-188-3p

Lung cancer has a high morbidity and mortality among malignant tumors, and lung adenocarcinoma (LUAD) is the main type of lung cancer. In recent years, circular RNAs (circRNAs) have been confirmed to play an important role in the generation and development of human cancer. However, the specific role and mechanism of circ-NUP98 in LUAD are still unclear and need to be further investigated. Circ-NUP98, microRNA-188-3p (miR-188-3p), and chromobox homolog 1 (CBX1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell-counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry, wound healing, and transwell assay were used to observe LUAD cell proliferation, apoptosis, migration, invasion, and cell-cycle progression. Malondialdehyde (MDA) and superoxide dismutase (SOD) levels were examined using special assay kits. CyclinD1, Bcl-2-related X protein (Bax), matrix metalloproteinase 9 (MMP9) protein, and CBX1 protein levels were determined using Western blot. The interaction between miR-188-3p and circ-NUP98 or CBX1 was identified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assay. In vivo efficacy of circ-NUP98 was evaluated in a xenograft tumor model. Besides, the expression of CBX1 and KI67 in the tumors was detected by immunohistochemical (IHC) assay. Circ-NUP98 and CBX1 expressions were upregulated in LUAD tissues and cells, and miR-188-3p was decreased. Downregulation of circ-NUP98 could inhibit the proliferation, migration, invasion, and oxidative stress, and promote apoptosis of LUAD cells. Mechanism experiments showed that circ-NUP98 acted as a sponge for miR-188-3p to increase CBX1 expression. Knockdown of circ-NUP98 could inhibit the growth of LUAD tumors in vivo. Circ-NUP98 might promote the malignant development of LUAD via the miR-188-3p/CBX1 axis, which might provide a potential new marker for early diagnosis of LUAD.

Cooperation of MLL1 and Jun in controlling H3K4me3 on enhancers in colorectal cancer

BACKGROUND

Enhancer dysregulation is one of the important features for cancer cells. Enhancers enriched with H3K4me3 have been implicated to play important roles in cancer. However, their detailed features and regulatory mechanisms have not been well characterized.

RESULTS

Here, we profile the landscape of H3K4me3-enriched enhancers (m3Es) in 43 pairs of colorectal cancer (CRC) samples. M3Es are widely distributed in CRC and averagely possess around 10% of total active enhancers. We identify 1322 gain variant m3Es and 367 lost variant m3Es in CRC. The target genes of the gain m3Es are enriched in immune response pathways. We experimentally prove that repression of CBX8 and RPS6KA5 m3Es inhibits target gene expression in CRC. Furthermore, we find histone methyltransferase MLL1 is responsible for depositing H3K4me3 on the identified Vm3Es. We demonstrate that the transcription factor AP1/JUN interacts with MLL1 and regulates m3E activity. Application of a small chemical inhibitor for MLL1 activity, OICR-9429, represses target gene expression of the identified Vm3Es, enhances anti-tumor immunity and inhibits CRC growth in an animal model.

CONCLUSIONS

Taken together, our study illustrates the genome-wide landscape and the regulatory mechanisms of m3Es in CRC, and reveals potential novel strategies for cancer treatment.

An EMT-Related Gene Signature to Predict the Prognosis of Triple-Negative Breast Cancer

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is an important biological process in tumor invasion and metastasis, and thus a potential indicator of the progression and drug resistance of breast cancer. This study comprehensively analyzed EMT-related genes in triple-negative breast cancer (TNBC) to develop an EMT-related prognostic gene signature.

METHODS

With the application of The Cancer Genome Atlas (TCGA) database, Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), and the Genotype-Tissue Expression (GTEx) database, we identified EMT-related signature genes (EMGs) by Cox univariate regression and LASSO regression analysis. Risk scores were calculated and used to divide patients with TNBC into high-risk group and low-risk groups by the median value. Kaplan-Meier (K-M) and receiver operating characteristic (ROC) curve analyses were applied for model validation. Independent prognostic predictors were used to develop nomograms. Then, we assessed the risk model in terms of the immune microenvironment, genetic alteration and DNA methylation effects on prognosis, the probability of response to immunotherapy and chemotherapy, and small molecule drugs predicted by The Connectivity Map (Cmap) database.

RESULTS

Thirteen EMT-related genes with independent prognostic value were identified and used to stratify the patients with TNBC into high- and low-risk groups. The survival analysis revealed that patients in the high-risk group had significantly poorer overall survival than patients in the low-risk group. Populations of immune cells, including CD4 memory resting T cells, CD4 memory activated T cells, and activated dendritic cells, significantly differed between the high- and low-risk groups. Moreover, some therapeutic drugs to which the high-risk group might show sensitivity were identified.

CONCLUSIONS

Our research identified the significant impact of EMGs on prognosis in TNBC, providing new strategies for personalizing TNBC treatment and improving clinical outcomes.

CBX3 promotes clear cell renal carcinoma through PI3K/AKT activation and aberrant immunity

BACKGROUND

A chromobox homologue 3 (CBX3) is elevated in various cancers and significantly contributes to the promotion of malignant behavior; despite this, its exact involvement in clear cell renal cell carcinoma (ccRCC) is yet unknown.

METHODS

The Cancer Genome Atlas database served to evaluate CBX3 production and its connection to survival in patients with ccRCC. Our team evaluated the effects of knockdown of CBX3 levels in ccRCC cell populations using in vitro together with in vivo models. CBX3, proteins related to death, and epithelial-to-mesenchymal transition (EMT)-related proteins were measured in ccRCC cells using western blotting and immunohistochemical assays. Through the analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) and GeneOntology (GO) and Gene Set Enrichment Analysis (GSEA), the biological processes and signal pathways related to CBX3 expression were identified. Immune-related activity reduced by CBX3 was assessed using various online tools.

RESULTS

Both genomic and protein expression showed that CBX3 was upregulated in ccRCC. Further functional analyses revealed that CBX3 played a crucial role in enhancing cell growth, migration, and EMT in vitro along with in vivo. Moreover, the study results provided distinct mechanistic evidence that CBX3 exerts its pathological functions in ccRCC by activating the PI3K/AKT pathway. Finally, immunoassays revealed that CBX3, a possible biomarker of ccRCC, was significantly associated with immunity.

CONCLUSIONS

Our results suggest that the overexpression of CBX3 promotes ccRCC advancement through PI3K/AKT activation and even immunological dysregulation, making it a potentially viable and beneficial therapeutic target.

Construction of a novel nomogram based on competing endogenous RNAs and tumor-infiltrating immune cells for prognosis prediction in elderly patients with colorectal cancer

Competitive endogenous RNAs (ceRNAs) and tumor-infiltrating immune cells play essential roles in colorectal cancer (CRC) tumorigenesis. However, their prognostic role in elderly patients with CRC is unclear. Gene expression profiles and clinical information for elderly patients with CRC were downloaded from The Cancer Genome Atlas. Univariate, LASSO, and multivariate Cox regression analyses were utilized for screening key ceRNAs and prevent overfitting. A total of 265 elderly patients with CRC were included. We constructed a novel ceRNA network consisting of 17 lncRNAs, 35 miRNAs, and 5 mRNAs. We established three prognosis predictive nomograms based on four key ceRNAs (ceRNA nomogram), five key immune cells (immune cell nomogram), and their combination (ceRNA-immune cell nomogram). Among them, the ceRNA-immune cell nomogram had the best accuracy. Furthermore, the areas under the curve of the ceRNA-immune cell nomogram were also significantly greater than the TNM stage at 1 (0.818 vs. 0.693), 3 (0.865 vs. 0.674), and 5 (0.832 vs. 0.627) years. Co-expression analysis revealed that CBX6 was positively correlated with activated dendritic cells (R = 0.45, p < 0.01), whereas negatively correlated with activated mast cells (R =- 0.43, p < 0.01). In conclusion, our study constructed three nomograms to predict prognosis in elderly patients with CRC, among which the ceRNA-immune cell nomogram had the best prediction accuracy. We inferred that the mechanism underlying the regulation of activated dendritic cells and mast cells by CBX6 might play a crucial role in tumor development and prognosis of elderly patients with CRC.

Multi-Omics Data Analysis Identifies Prognostic Biomarkers across Cancers

Combining omics data from different layers using integrative methods provides a better understanding of the biology of a complex disease such as cancer. The discovery of biomarkers related to cancer development or prognosis helps to find more effective treatment options. This study integrates multi-omics data of different cancer types with a network-based approach to explore common gene modules among different tumors by running community detection methods on the integrated network. The common modules were evaluated by several biological metrics adapted to cancer. Then, a new prognostic scoring method was developed by weighting mRNA expression, methylation, and mutation status of genes. The survival analysis pointed out statistically significant results for GNG11, CBX2, CDKN3, ARHGEF10, CLN8, SEC61G and PTDSS1 genes. The literature search reveals that the identified biomarkers are associated with the same or different types of cancers. Our method does not only identify known cancer-specific biomarker genes, but also proposes new potential biomarkers. Thus, this study provides a rationale for identifying new gene targets and expanding treatment options across cancer types.

Comprehensive bioinformatics analysis of the expression, prognostic value, and immune infiltration of chromobox family members in cervical cancer

Objectives

Cervical cancer (CC) is the fourth most prevalent type of cancer in women worldwide and it is considered the leading cause of tumor-related death and malignancy. As part of complexes involved in epigenetic control, the proteins of the chromobox (CBX) family have been found to have a role in the growth of malignancies by preventing differentiation and increasing proliferation. Here, by a thorough investigation, we investigated the expression, prognostic significance, and immune infiltration of CBX in patients with CC.

Materials and Methods

Differential expression, clinicopathological parameters, immune cell infiltration, enrichment analysis, genetic alteration, and prognostic value of CBXs in patients with CC were examined using TIMER, Metascape, STRING, GeneMANIA, cBioPortal, UALCAN, The Human Protein Atlas, Gene Expression Profiling Interactive Analysis (GEPIA), and Oncomine.

Results

In CC tissues, CBX 2/3/4/5 and CBX 8 expression levels were considerably higher, whereas CBX 6/7 expression levels were lower. In CC, the CBX 5/6/8 promoters have elevated levels of methylation. The expression of CBX 2/6/8 and the pathological stage were connected. A 37% mutation rate of the differentially expressed CBX genes was observed. Also, there was a strong correlation of the CBXs expression with immune cell infiltration, such as T CD4⁺ cells, macrophages, neutrophils, B cells, T CD8⁺ cells, and dendritic cells.

Conclusion

The investigation discovered that members of the CBXs family may be therapeutic targets for CC patients and may play significant roles in the development of CC tumors.

CCNE1 is a predictive and immunotherapeutic indicator in various cancers including UCEC: a pan-cancer analysis

BACKGROUND

CCNE1 plays an important oncogenic role in several tumors, especially high-stage serous ovarian cancer and endometrial cancer. Nevertheless, the fundamental function of CCNE1 has not been explored in multiple cancers. Therefore, bioinformatics analyses of pan-cancer datasets were carried out to explore how CCNE1 regulates tumorigenesis.

METHODS

A variety of online tools and cancer databases, including GEPIA2, SangerBox, LinkedOmics and cBioPortal, were applied to investigate the expression of CCNE1 across cancers. The pan-cancer datasets were used to search for links between CCNE1 expression and prognosis, DNA methylation, m6A level, genetic alterations, CCNE1-related genes, and tumor immunity. We verified that CCNE1 has biological functions in UCEC cell lines using CCK-8, EdU, and Transwell assays.

RESULTS

In patients with different tumor types, a high mRNA expression level of CCNE1 was related to a poor prognosis. Genes related to CCNE1 were connected to the cell cycle, metabolism, and DNA damage repair, according to GO and KEGG enrichment analyses. Genetic alterations of CCNE1, including duplications and deep mutations, have been observed in various cancers. Immune analysis revealed that CCNE1 had a strong correlation with TMB, MSI, neoantigen, and ICP in a variety of tumor types, and this correlation may have an impact on the sensitivity of various cancers to immunotherapy. CCK-8, EdU and Transwell assays suggested that CCNE1 knockdown can suppress UCEC cell proliferation, migration and invasion.

CONCLUSION

Our study demonstrated that CCNE1 is upregulated in multiple cancers in the TCGA database and may be a promising predictive biomarker for the immunotherapy response in some types of cancers. Moreover, CCNE1 knockdown can suppress the proliferation, migration and invasion of UCEC cells.

Chromobox proteins in cancer: Multifaceted functions and strategies for modulation (Review)

Chromobox (CBX) proteins are important epigenetic regulatory proteins and are widely involved in biological processes, such as embryonic development, the maintenance of stem cell characteristics and the regulation of cell proliferation and apoptosis. Disorder and dysfunction of CBXs in cancer usually lead to the blockade or ectoptic activation of developmental pathways, promoting the occurrence, development and progression of cancer. In the present review, the characteristics and functions of CBXs were first introduced. Subsequently, the expression of CBXs in cancers and the relationship between CBXs and clinical characteristics (mainly cancer grade, stage, metastasis and relapse) and prognosis were discussed. Finally, it was described how CBXs regulate cell proliferation and self‑renewal, apoptosis and the acquisition of malignant phenotypes, such as invasion, migration and chemoresistance, through mechanisms involving epigenetic modification, nuclear translocation, noncoding RNA interactions, transcriptional regulation, posttranslational modifications, protein‑protein interactions, signal transduction and metabolic reprogramming. The study also focused on cancer therapies targeting CBXs. The present review provides new insight and a comprehensive basis for follow‑up research on CBXs and cancer.

Penetrating Exploration of Prognostic Correlations of the FKBP Gene Family with Lung Adenocarcinoma

The complexity of lung adenocarcinoma (LUAD), the development of which involves many interacting biological processes, makes it difficult to find therapeutic biomarkers for treatment. FK506-binding proteins (FKBPs) are composed of 12 members classified as conservative intracellular immunophilin family proteins, which are often connected to cyclophilin structures by tetratricopeptide repeat domains and have peptidyl prolyl isomerase activity that catalyzes proline from residues and turns the trans form into the cis form. Since FKBPs belong to chaperone molecules and promote protein folding, previous studies demonstrated that FKBP family members significantly contribute to the degradation of damaged, misfolded, abnormal, and foreign proteins. However, transcript expressions of this gene family in LUAD still need to be more fully investigated. In this research, we adopted high-throughput bioinformatics technology to analyze FKBP family genes in LUAD to provide credible information to clinicians and promote the development of novel cancer target drugs in the future. The current data revealed that the messenger (m)RNA levels of FKBP2, FKBP3, FKBP4, FKBP10, FKBP11, and FKBP14 were overexpressed in LUAD, and FKBP10 had connections to poor prognoses among LUAD patients in an overall survival (OS) analysis. Based on the above results, we selected FKBP10 to further conduct a comprehensive analysis of the downstream pathway and network. Through a DAVID analysis, we found that FKBP10 was involved in mitochondrial electron transport, NADH to ubiquinone transport, mitochondrial respiratory chain complex I assembly, etc. The MetaCore pathway analysis also indicated that FKBP10 was involved in "Ubiquinone metabolism", "Translation_(L)-selenoaminoacid incorporation in proteins during translation", and "Transcription_Negative regulation of HIF1A function". Collectively, this study revealed that FKBP family members are both significant prognostic biomarkers for lung cancer progression and promising clinical therapeutic targets, thus providing new targets for treating LUAD patients.

SCAND1 Reverses Epithelial-to-Mesenchymal Transition (EMT) and Suppresses Prostate Cancer Growth and Migration

Epithelial-mesenchymal transition (EMT) is a reversible cellular program that transiently places epithelial (E) cells into pseudo-mesenchymal (M) cell states. The malignant progression and resistance of many carcinomas depend on EMT activation, partial EMT, or hybrid E/M status in neoplastic cells. EMT is activated by tumor microenvironmental TGFβ signal and EMT-inducing transcription factors, such as ZEB1/2, in tumor cells. However, reverse EMT factors are less studied. We demonstrate that prostate epithelial transcription factor SCAND1 can reverse the cancer cell mesenchymal and hybrid E/M phenotypes to a more epithelial, less invasive status and inhibit their proliferation and migration in DU-145 prostate cancer cells. SCAND1 is a SCAN domain-containing protein and hetero-oligomerizes with SCAN-zinc finger transcription factors, such as MZF1, for accessing DNA and the transcriptional co-repression of target genes. We found that SCAND1 expression correlated with maintaining epithelial features, whereas the loss of SCAND1 was associated with mesenchymal phenotypes of tumor cells. SCAND1 and MZF1 were mutually inducible and coordinately included in chromatin with hetero-chromatin protein HP1γ. The overexpression of SCAND1 reversed hybrid E/M status into an epithelial phenotype with E-cadherin and β-catenin relocation. Consistently, the co-expression analysis in TCGA PanCancer Atlas revealed that SCAND1 and MZF1 expression was negatively correlated with EMT driver genes, including CTNNB1, ZEB1, ZEB2 and TGFBRs, in prostate adenocarcinoma specimens. In addition, SCAND1 overexpression suppressed tumor cell proliferation by reducing the MAP3K-MEK-ERK signaling pathway. Of note, in a mouse tumor xenograft model, SCAND1 overexpression significantly reduced Ki-67(+) and Vimentin(+) tumor cells and inhibited migration and lymph node metastasis of prostate cancer. Kaplan-Meier analysis showed high expression of SCAND1 and MZF1 to correlate with better prognoses in pancreatic cancer and head and neck cancers, although with poorer prognosis in kidney cancer. Overall, these data suggest that SCAND1 induces expression and coordinated heterochromatin-binding of MZF1 to reverse the hybrid E/M status into an epithelial phenotype and, inhibits tumor cell proliferation, migration, and metastasis, potentially by repressing the gene expression of EMT drivers and the MAP3K-MEK-ERK signaling pathway.

Comprehensive analysis of prognostic value, relationship to cell cycle, immune infiltration and m6A modification of ZSCAN20 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common tumor across the globe with a high mortality rate. ZSCAN20 is a ZNF transcription factor, a key determinant of gene expression. Nonetheless, the mechanism of ZSCAN20 as a potential clinical biomarker and therapeutic target for HCC is not understood. Here, TIMER, TCGA, ICGC databases and immunohistochemical (IHC) and Western Blot found ZSCAN20 mRNA and protein levels were upregulated. Additionally, Kaplan-Meier Plotter, GEPIA and TCGA databases showed high ZSCAN20 expression was related to the short survival time of HCC patients. Multivariate Cox analysis exposed that ZSCAN20 can act as an independent prognostic factor. We observed methylation level of ZSCAN20 was associated with the clinicopathological characteristics and prognosis of HCC patients through UALCAN. Furthermore, enrichment examination exposed functional association between ZSCAN20 and cell cycle, immune infiltration. Functional experiments showed that interference with ZSCAN20 significantly reduced the invasion, migration and proliferation abilities of HCC cells. An immune infiltration analysis showed that ZSCAN20 was associated with immune cells, particularly T cells. The expression of ZSCAN20 was correlated with poor prognosis in the Regulatory T-cell. And Real-Time RT-PCR analysis found interference with ZSCAN20 significantly reduced the expression of some chemokines. Finally, the TCGA and ICGC data analysis suggested that the ZSCAN20 expression was greatly related to m6A modifier related genes. In conclusion, ZSCAN20 can serve as a prognostic biomarker for HCC and provide clues about cell cycle, immune infiltration, and m6A modification.

N6 -Methyladenosine-Modified CBX1 Regulates Nasopharyngeal Carcinoma Progression Through Heterochromatin Formation and STAT1 Activation

Epitranscriptomic remodeling such as N⁶ -methyladenosine (m⁶ A) modification plays a critical role in tumor development. However, little is known about the underlying mechanisms connecting m⁶ A modification and nasopharyngeal carcinoma (NPC) progression. Here, CBX1 is identified, a histone methylation regulator, to be significantly upregulated with m⁶ A hypomethylation in metastatic NPC tissues. The m⁶ A-modified CBX1 mRNA transcript is recognized and destabilized by the m⁶ A reader YTHDF3. Furthermore, it is revealed that CBX1 promotes NPC cell migration, invasion, and proliferation through transcriptional repression of MAP7 via H3K9me3-mediated heterochromatin formation. In addition to its oncogenic effect, CBX1 can facilitate immune evasion through IFN-γ-STAT1 signaling-mediated PD-L1 upregulation. Clinically, CBX1 serves as an independent predictor for unfavorable prognosis in NPC patients. The results reveal a crosstalk between epitranscriptomic and epigenetic regulation in NPC progression, and shed light on the functions of CBX1 in tumorigenesis and immunomodulation, which may provide an appealing therapeutic target in NPC.

Identification and validation of the molecular subtype and prognostic signature for clear cell renal cell carcinoma based on neutrophil extracellular traps

Background: Renal cell carcinoma (RCC) is one of the most common cancers, with an annual incidence of nearly 400,000 cases worldwide. Increasing evidence has also demonstrated the vital role of neutrophil extracellular traps (NETs) in cancer progression and metastatic dissemination. Methods: Consensus cluster analysis was performed to determine the number of ccRCC subtypes. The Kruskal-Wallis test or Student t-test was performed to evaluate the difference of infiltrating immune cell and gene expression in different groups. The Kaplan-Meier (KM) method was used to draw the survival curve. LASSO cox regression analysis was conducted to construct a NET-related prognostic signature. We also constructed a lncRNA-miRNA-mRNA regulatory axis by several miRNA and lncRNA target databases. Results: A total of 23 differentially expressed NET-related genes were obtained in ccRCC. Three clusters of ccRCC cases with significant difference in prognosis, immune infiltration, and chemotherapy and targeted therapy were identified. LASSO Cox regression analysis identified a NET-related prognostic signature including six genes (G0S2, DYSF, MMP9, SLC22A4, SELP, and KCNJ15), and this signature had a good performance in predicting the overall survival of ccRCC patients. The expression of prognostic signature genes was significantly correlated with the pTMN stage, immune infiltration, tumor mutational burdens, microsatellite instability, and drug sensitivity of ccRCC patients. MMP9 was identified as the hub gene. We also identified the lncRNA UBA6-AS1/miR-149-5p/MMP9 regulatory axis for the progression of ccRCC. Conclusion: Collectively, the current study identified three molecular clusters and a prognostic signature for ccRCC based on neutrophil extracellular traps. Integrative transcriptome analyses plus clinical sample validation may facilitate the biomarker discovery and clinical transformation.

CBX Family Members in Two Major Subtypes of Renal Cell Carcinoma: A Comparative Bioinformatic Analysis

The biological function and clinical values of Chromobox (CBX) family proteins in renal cell carcinoma (RCC) are still poorly investigated. This study aimed to compare the expression profiles and clinical relevance of CBXs between the two most frequent subtypes of RCC, clear cell renal cell carcinomas (ccRCC) and papillary renal cell carcinomas (pRCC), and to investigate whether CBXs would play a more or less similar role in the pathogenesis and progression of these RCC subtypes. Considering these two RCC populations in the TCGA database, we built a bioinformatics framework by integrating a computational pipeline with several online tools. CBXs showed a similar trend in ccRCC and pRCC tissues but with some features specific for each subtype. Specifically, the relative expressions of CBX3 and CBX2 were, respectively, the highest and lowest among all CBXs in both RCC subtypes. These data also found confirmation in cellular validation. Except for CBX4 and CBX8, all others were deregulated in the ccRCC subtype. CBX1, CBX6, and CBX7 were also significantly associated with the tumor stage. Further, low expression levels of CBX1, CBX5, CBX6, CBX7, and high expression of CBX8 were associated with poor prognosis. Otherwise, in the pRCC subtype, CBX2, CBX3, CBX7, and CBX8 were deregulated, and CBX2, CBX6, and CBX7 were associated with the tumor stage. In addition, in pRCC patients, low expression levels of CBX2, CBX4, and CBX7 were associated with an unfavorable prognosis. Similarly, CBX3, CBX6, and CBX7 presented the highest alteration rate in both subtypes and were found to be functionally related to histone binding, nuclear chromosomes, and heterochromatin. Furthermore, CBX gene expression levels correlated with immune cell infiltration, suggesting that CBXs might reflect the immune status of RCC subtypes. Our results highlight similarities and differences of CBXs within the two major RCC subtypes, providing new insights for future eligible biomarkers or possible molecular therapeutic targets for these diseases.

Systematic investigation of the clinical significance and prognostic value of the CBXs in esophageal cancer

Esophageal cancer (ESCA), one of the most aggressive malignant tumors, has been announced to be the ninth most common cancer and the sixth leading cause of cancer-related death in the world. Chromobox family members (CBXs) are important epigenetic regulators which are related with the transcription of target genes. The role of CBXs in carcinomas has been reported in many studies. However, the function and prognostic value of different CBXs in ESCA are still largely unknown. In this article, we first performed differential expression analysis through several methods including Oncomine and Gene Expression Profiling Interactive Analysis. The results led us to determine the differential expression of CBXs in pan-cancer, especially ESCA. Then we evaluated the prognostic value of different CBX messenger RNA (mRNA) expression in patients with ESCA through the Kaplan-Meier plotter and the Human Protein Atlas database. In addition, we used cBioPortal to explore all genetic alterations and mutations in the CBXs in ESCA. Simultaneously, the correlation between its expression and the level of immune infiltration of ESCA was visualized by TIMER. Finally, the biological function of CBXs in ESCA is obtained through Biological Enrichment Analysis including gene ontology and Kyoto Encyclopedia of Genes and Genomes. The expression levels of CBX3/4/5 and CBX8 in ESCA tissues increased significantly and the expression level of CBX7 decreased through differential expression analysis. Additionally, CBX1 is significantly related to the clinical cancer stage and disease-free survival of ESCA patients. The high mRNA expression of CBX4 is related to the short overall survival of patients with esophageal squamous cell carcinoma, and the high mRNA expression of CBX3/7/8 is related to the short overall survival of patients with esophageal adenocarcinoma, indicating that CBX1/3/4/7/8 may be a potential prognostic biomarker for the survival of ESCA patients. Besides, the expression of CBXs is significantly related to the infiltration of a variety of immune cells, including six types of CD4-positive T-lymphocytes, macrophages, neutrophils, bursindependentlymphocyte, CD8-positive T-lymphocytes cells and dendritic cells in ESCA. Moreover, we found that CBXs are mainly associated with the inhibition of cell cycle and apoptosis pathway. Further, enrichment analysis indicated that CBXs and correlated genes were enriched in mismatch repair, DNA replication, cancer pathways, and spliceosomes. Our research may provide new insights into the choice of prognosis biomarkers of the CBXs in ESCA.

DHRS7 is an immune-related prognostic biomarker of KIRC and pan-cancer

Renal clear cell carcinoma (KIRC) is one malignancy whose development and prognosis have been associated with aberrant DHRS7 expression. However, the catalytic activity and pathophysiology of KIRC are poorly understood, and no sensitive tumor biomarkers have yet been discovered. In our study, we examined the significant influence of DHRS7 on the tumor microenvironment (TME) and tumor progression using an overall predictable and prognostic evaluation approach. We found novel cancer staging, particularly in KIRC, as well as potential therapeutic drugs out of 27 drug sensitivity tests. Using Perl scripts, it was possible to determine the number of somatic mutations present in 33 tumors, as well as the relative scores of 22 immune cells using CIBERSORT, the relationship between immune infiltration and differential expression using TCGA data, and the immune microenvironment score using the estimate technique. Our results show that DHRS7 is abnormally expressed in pan-cancer patients, which influences their survival. Low DHRS7 expression was associated with late clinical stages and a low survival rate in KIRC patients, suggesting a poor prognosis and course of treatment, in HNSG, MESO, and KIRC patients. We also found that DHRS7 was associated with TMB and MSI in certain tumors. Using KIRC as an example, we discovered a negative correlation between DHRS7 expression and immunological assessments, suggesting that this substance might be used as a tumor biomarker.

Expression and Prognostic Value of Chromobox Family Proteins in Esophageal Cancer

Background: Esophageal cancer (EC) is one of the most common human malignant tumors worldwide. Chromobox (CBX) family proteins are significant components of epigenetic regulatory complexes. It is reported that CBXs play critical roles in the oncogenesis and development of various tumors. Nonetheless, their functions and specific roles in EC remain vague and obscure. Methods and Materials: We used multiple bioinformatics tools, including Oncomine, Gene Expression Profiling Interactive Analysis 2 (GEPIA2), UALCAN, Kaplan–Meier plotter, cBioPortal, Metascape, TIMER2 and TISIDB, to investigate the expression profile, gene alterations and prognostic roles of CBX family proteins, as well as their association with clinicopathologic parameters, immune cells and immune regulators. In addition, RT-qPCR, Western blot, CCK8, colony formation, wound healing and transwell assays were performed to investigate the biological functions of CBX3 in EC cells. Results: CBX3 and CBX5 were overexpressed in EC compared to normal tissues. Survival analysis revealed that high expression of CBX1 predicted worse disease-free survival (DFS) in EC patients. Functionally, CBXs might participate in mismatch repair, spliceosome, cell cycle, the Fanconi anemia pathway, tight junction, the mRNA surveillance pathway and the Hippo signaling pathway in EC development. Furthermore, CBXs were related to distinct immune cells infiltration and immune regulators. Additionally, depletion of CBX3 inhibited the proliferation, migration and invasion abilities of EC cells. Conclusions: Our study comprehensively investigated the expression pattern, prognostic value, and gene alterations of CBXs in EC, as well as their relationships with clinicopathologic variables, immune cells infiltration and immune regulators. These results suggested that CBX family proteins, especially CBX3, might be potential biomarkers in the progression of EC.

Identifying potential prognosis markers in hepatocellular carcinoma via integrated bioinformatics analysis and biological experiments

Background: Hepatocellular carcinoma is one kind of clinical common malignant tumor with a poor prognosis, and its pathogenesis remains to be clarified urgently. This study was performed to elucidate key genes involving HCC by bioinformatics analysis and experimental evaluation.

Methods: We identified common differentially expressed genes (DEGs) based on gene expression profile data of GSE60502 and GSE84402 from the Gene Expression Omnibus (GEO) database. Gene Ontology enrichment analysis (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, REACTOME pathway enrichment analysis, and Gene Set Enrichment Analysis (GSEA) were used to analyze functions of these genes. The protein-protein interaction (PPI) network was constructed using Cytoscape software based on the STRING database, and Molecular Complex Detection (MCODE) was used to pick out two significant modules. Hub genes, screened by the CytoHubba plug-in, were validated by Gene Expression Profiling Interactive Analysis (GEPIA) and the Human Protein Atlas (HPA) database. Then, the correlation between hub genes expression and immune cell infiltration was evaluated by Tumor IMmune Estimation Resource (TIMER) database, and the prognostic values were analyzed by Kaplan-Meier plotter. Finally, biological experiments were performed to illustrate the functions of RRM2.

Results: Through integrated bioinformatics analysis, we found that the upregulated DEGs were related to cell cycle and cell division, while the downregulated DEGs were associated with various metabolic processes and complement cascade. RRM2, MAD2L1, MELK, NCAPG, and ASPM, selected as hub genes, were all correlated with poor overall prognosis in HCC. The novel RRM2 inhibitor osalmid had anti-tumor activity, including inhibiting proliferation and migration, promoting cell apoptosis, blocking cell cycle, and inducing DNA damage of HCC cells.

Conclusion: The critical pathways and hub genes in HCC progression were screened out, and targeting RRM2 contributed to developing new therapeutic strategies for HCC.

Development of an Accessible Gene Expression Bioinformatics Pipeline to Study Driver Mutations of Colorectal Cancer

Colorectal cancer (CRC) is a global cause of cancer-related mortality driven by genetic and environmental factors which influence therapeutic outcomes. The emergence of next-generation sequencing technologies enables the rapid and extensive collection and curation of genetic data for each cancer type into clinical gene expression biobanks. We report the application of bioinformatics tools for investigating the expression patterns and prognostic significance of three genes that are commonly dysregulated in colon cancer: adenomatous polyposis coli (APC); B-Raf proto-oncogene (BRAF); and Kirsten rat sarcoma viral oncogene homologue (KRAS). Through the use of bioinformatics tools, we show the patterns of APC, BRAF and KRAS genetic alterations and their role in patient prognosis. Our results show mutation types, the frequency of mutations, tumour anatomical location and differential expression patterns for APC, BRAF and KRAS for colorectal tumour and matched healthy tissue. The prognostic value of APC, BRAF and KRAS genetic alterations was investigated as a function of their expression levels in CRC. In the era of precision medicine, with significant advancements in biobanking and data curation, there is significant scope to use existing clinical data sets for evaluating the role of mutational drivers in carcinogenesis. This approach offers the potential for studying combinations of less well-known genes and the discovery of novel biomarkers, or for studying the association between various effector proteins and pathways.

High Expression of a Cancer Stemness-Related Gene, Chromobox 8 (CBX8), in Normal Tissue Adjacent to the Tumor (NAT) Is Associated with Poor Prognosis of Colorectal Cancer Patients

Background: Several studies have demonstrated that the molecular profile of normal tissue adjacent to the tumor (NAT) is prognostic for recurrence in patients with different cancers. This study investigated the clinical significance of CBX8 gene expression, a cancer stemness-related gene, in tumor and NAT tissue of colorectal cancer (CRC) patients. Methods: The gene level of CBX8 in paired CRC and NAT specimens from 95 patients was determined by quantitative PCR. CBX8 protein level in CRC and NAT specimens from 66 patients was determined by immunohistochemistry. CBX8 gene and protein levels were correlated with the patients’ clinicopathological parameters and circulatory immune cell profiles. The association between CBX8 and pluripotency-associated genes was analyzed using the TCGA database. Results: NAT CBX8 gene level positively correlated with TNM stage, tumor invasion, lymph node metastasis and distant metastasis, indicating its association with tumor progression and metastasis. There was no correlation between NAT CBX8 protein level and clinicopathological parameters. Moreover, a high level of CBX8 gene and protein in NAT both correlated with poor DFS and OS. There was an inverse correlation between CBX8 gene level and post-operative platelet counts and platelet to lymphocyte level, suggesting its association with systematic inflammation. Finally, TCGA analysis showed that CBX8 level was correlated with a couple of pluripotency-associated genes, supporting its association with cancer stemness. Conclusions: High NAT CBX8 is a poor prognostic factor for tumor progression and survival in CRC patients.

Chromobox homolog 4 overexpression inhibits TNF-α-induced matrix catabolism and senescence by suppressing activation of the NF-κB signaling pathway in nucleus pulposus cells

Intervertebral disc degeneration (IDD) is featured as enhanced catabolism of extracellular matrix (ECM) in the nucleus pulposus (NP), in which tumor necrosis factor-alpha (TNF-α)-related cell senescence is involved. Chromobox homolog protein 4 (CBX4) exhibits anti-inflammatory effects and shows promising therapeutic potential. Thus, in the present study, we explore the role of CBX4 in IDD. Immunohistochemistry staining reveals that CBX4 expression is decreased in severe degenerative NP tissues compared to mild degenerative tissues, and real-time PCR and western blot analysis results show that CBX4 expression is downregulated under TNF-α stimulation in NP cells. siRNA and adenoviruses are used to knockdown or overexpress CBX4, respectively. The results demonstrate that CBX4 knockdown augments the catabolism of ECM in human NP cells, while CBX4 overexpression in rat NP cells restores the ECM degradation induced by TNF-α, as illustrated by immunofluorescence and western blot analysis. In addition, transcriptome sequencing results reveal the regulatory effect of CBX4 on the cell cycle, and further western blot analysis and senescence-associated β-galactosidase staining assay indicate that CBX4 overexpression alleviates cell senescence in the presence of TNF-α. Moreover, the phosphorylation of p65, which indicates the activation of NF-κB signaling, is measured by western blot analysis and immunofluorescence assay, and the results reveal that CBX4 overexpression reduces the TNF-α-induced increase in the p-p65/p65 ratio. In addition, the effect of CBX4 overexpression in NP cells is suppressed by NF-κB agonist. In summary, our results indicate that CBX4 overexpression can suppress TNF-α-induced matrix catabolism and cell senescence in the NP by inhibiting NF-κB activation. This study may provide new approaches for preventing and treating IDD.

Circ_0037866 Contributes to the Tumorigenesis of Renal Cell Carcinoma by Sequestering miR-384 to Elevate Chromobox 5 Expression

BACKGROUND

Circular RNAs (circRNAs) were demonstrated to have roles in the carcinogenesis of renal cell carcinoma (RCC). Hence, this work aimed to determine the functions and molecular mechanism of circ_0037866 in regulating the progression of RCC.

METHODS

Quantitative real-time polymerase chain reaction and Western blotting were used to detect the levels of genes and proteins. In vitro assays, including colony formation, 5-ethynyl-2'-deoxyuridine, flow cytometry, transwell assays, and in vivo tumor formation, were conducted to investigate the effects of circ_0037866 on RCC tumorigenesis. Dual-luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation assay were used to confirm the interaction between miR-384 and circ_0037866 or Chromobox 5 (CBX5).

RESULTS

Circ_0037866 is a stable circRNA and was found to be increased in RCC tissues and cells. Functionally, circ_0037866 silencing suppressed RCC cell survival, invasion, and migration in vitro, and impeded RCC cell tumorigenesis in the subcutaneous xenograft model. Mechanistically, circ_0037866 could function as a sponge for miR-384 to elevate the expression of its target CBX5. Furthermore, a series of rescue experiments showed that miR-384 inhibition reversed the anticancer effects of circ_0037866 knockdown on RCC cells; besides that, miR-384 restoration suppressed RCC cell growth and mobility, which were attenuated by CBX5 overexpression.

CONCLUSION

Circ_0037866 knockdown restrains the tumorigenesis of RCC by miR-384/CBX5, revealing a promising molecular target for RCC therapy.

Antioxidant and Anticancer Functions of Protein Acyltransferase DHHC3

Silencing of DHHC3, an acyltransferase enzyme in the DHHC family, extensively upregulates oxidative stress (OS). Substrates for DHHC3-mediated palmitoylation include several antioxidant proteins and many other redox regulatory proteins. This helps to explain why DHHC3 ablation upregulates OS. DHHC3 also plays a key role in cancer. DHHC3 ablation leads to diminished xenograft growth of multiple cancer cell types, along with diminished metastasis. Furthermore, DHHC3 protein is upregulated on malignant/metastatic cancer samples, and upregulated gene expression correlates with diminished patient survival in several human cancers. Decreased primary tumor growth due to DHHC3 ablation may be partly explained by an elevated OS → senescence → innate immune cell recruitment mechanism. Elevated OS due to DHHC3 ablation may also contribute to adaptive anticancer immunity and impair tumor metastasis. In addition, DHHC3 ablation disrupts antioxidant protection mechanisms, thus enhancing the efficacy of OS-inducing anticancer drugs. A major focus has thus far been on OS regulation by DHHC3. However, remaining to be studied are multiple DHHC3 substrates that may affect tumor behavior independent of OS. Nonetheless, the currently established properties of DHHC3 make it an attractive candidate for therapeutic targeting in situations in which antioxidant protections need to be downmodulated, and also in cancer.

Pan-Cancer Study of SHC-Adaptor Protein 1 (SHC1) as a Diagnostic, Prognostic and Immunological Biomarker in Human Cancer

Background: Recent studies highlight the carcinogenesis role of SHC-adaptor protein 1 (SHC1) in cancer initiation, development, and progression. However, its aberrant expression, diagnostic and prognostic value remain unknown in a variety of tumors.

Methods: The SHC1 expression profiles were analyzed using GTEx database, TCGA database, Oncomine and CPTAC database. The survival analysis was conducted using GEPIA2, Kaplan-Meier Plotter, UALCAN, and PrognoScan. The diagnostic values of SHC1 were calculated with the “pROC” package in R software. The genetic alteration of SHC1 and mutations were analyzed using cBioPortal. TIMER2 was employed to estimate the correlations between SHC1 expression and tumor-infiltrating immune cells in the TCGA cohort. Enrichment analysis of SHC1 was conducted using the R package “clusterProfiler.”

Results: SHC1 was ubiquitously highly expressed and closely associated with worse prognosis of multiple major cancer types (all p < 0.05). Further, SHC1 gene mutations were strongly linked to poor OS and DFS in SKCM (all p < 0.05). An enhanced phosphorylation level of SHC1 at the S139 site was observed in clear cell RCC. Additionally, the results revealed SHC1 expression was strongly linked to TMB, MMRs, MSI, TAMs, DNA methylation, m6A RNA methylation, tumor-associated immune infiltration, and immune checkpoints in multiple cancers (all p < 0.05). In addition, the results of the ROC analysis indicated the SHC1 exhibited strong diagnostic capability for KICH (AUC = 0.92), LIHC (AUC = 0.95), and PAAD (AUC = 0.95). Finally, enrichment analysis indicated that SHC1 may potentially involve in the regulation of numerous signaling pathways in cancer metabolism and protein phosphorylation-related functions.

Conclusions: These findings highlight that SHC1 plays an important role in the tumor immune microenvironment, and SHC1 has been identified to have prognostic and diagnostic value in multiple cancers. Thus, SHC1 is a potential target for cancer immunotherapy and effective prognostic and diagnostic biomarker.

Identification and Validation of Chromobox Family Members as Potential Prognostic Biomarkers and Therapeutic Targets for Human Esophageal Cancer

Background: Chromobox family proteins (CBXs) are vital components of epigenetic regulation complexes and transcriptionally inhibit target genes by modifying the chromatin. Accumulating evidence indicates that CBXs are involved in the initiation and progression of multiple malignancies. However, the expression, function, and clinical relevance such as the prognostic and diagnostic values of different CBXs in esophageal carcinoma (ESCA) are still unclear.

Methods: We applied Oncomine, TCGA, GEO, GEPIA, UALCAN, Kaplan–Meier plotter, cBioPortal, Metascape, and TIMER to investigate the roles of CBX family members in ESCA. Additionally, quantitative real-time PCR (RT-PCR), western blot, and immunofluorescence were used to verify the expression of CBX family members in ESCA clinical samples.

Results: Compared with normal tissues, the mRNA expression levels of CBX1/3/8 were significantly increased in ESCA, whereas CBX7 mRNA expression was reduced in both the TCGA cohort and GEO cohort. In the TCGA cohort, ROC curves suggested that CBX1/2/3/4/8 had great diagnostic value in ESCA, and the AUCs were above 0.9. Furthermore, upregulation of CBX1/3/8 and downregulation of CBX7 were closely related to the clinicopathological parameters in ESCA patients, such as tumor grades, tumor nodal metastasis status, and TP53 mutation status. The survival analysis indicated that higher CBX1/3/8 mRNA expressions and lower CBX7 expression suggested an unfavorable prognosis in ESCA. High genetic change rate (52%) of CBXs was found in ESCA patients. Functions and pathways of mutations in CBXs and their 50 frequently altered neighbor genes in ESCA patients were investigated; the results showed that DNA repair and DNA replication were correlated to CBX alterations. Moreover, we found a significant correlation between the expression level of CBX family members and the infiltration of immune cells in ESCA. Finally, we verified the expression of CBX family members in clinical samples and found the results were consistent with the databases.

Conclusion: Our study implied that CBX1/3/7/8 are potential targets of precision therapy for ESCA patients and new biomarkers for the prognosis.

Expression profile and prognostic values of Chromobox family members in human glioblastoma

Glioblastoma (GBM) is the most common and deadly malignant primary brain tumor. Chromobox (CBX) family proteins are essential components of the epigenetic regulatory complex and are involved in the occurrence and development of various cancers. However, the roles of CBX members in GBM is little known. In this analysis, we synthesized several mainstream bioinformatics databases to comprehensively explore the expression profiles, prognostic implications, genetic alterations, immune infiltration, and potential biological functions of the CBXs in GBM, and cell experiments were also conducted to investigate the role of CBX8 in GBM. We found that the elevated mRNA expression of CBX2/3/5/8 and reduced mRNA expression of CBX6/7 were found in GBM. The protein levels of CBX2/3/5/8 were elevated in GBM tissues, whereas the protein levels of CBX6/7 showed no significant difference. The upregulated expression of CBX2/3/8 was found to be both correlated with the tumor grade and recurrent status. The overexpression of CBX3/8 and underexpression of CBX6 mRNA were associated with the poor prognosis. These findings suggested that CBX3 and CBX8 might be useful diagnostic and prognostic biomarkers in GBM. Further cell experiment results supported that CBX8 promoted the proliferation of glioma cells. Moreover, a high genetic alteration rate of CBXs (37%) was found in GBM and to varying degrees. The expression of CBXs was significantly related to the immune cells infiltration. CBX7 methylation level was significantly increased in GBM tissues. Our results may provide novel ideas to find potential prognostic markers and new therapeutic targets among CBX family members in glioblastoma.

Comprehensive pan-cancer analysis on CBX3 as a prognostic and immunological biomarker

Background

Increased evidence supports the relationship between chromobox protein homolog 3 (CBX3) and tumorigenesis of some cancers. However, the role of CBX3 in pan-cancers remains poorly defined. In the research, we aimed to investigate the prognostic value and the immunological functions of CBX3.

Results

We explored the potential oncogenic roles of CBX3 in mRNA and protein levels based on the diverse databases, including the expression, the correlation with prognosis, tumor microenvironment (TME), DNA methylation, protein phosphorylation and enrichment analysis across all TCGA tumors. The results show that CBX3 is overexpressed in multiple cancers, and significant correlations exist between high expression and adverse prognosis in most tumor patients. We observed an enhanced phosphorylation level in uterine corpus endometrial carcinoma, colon cancer and lung adenocarcinoma. A distinct relationship was also found between CBX3 expression and TME, including immune infiltration of tumor-infiltrating lymphocytes and cancer-associated fibroblasts, immune score or matrix score, immune checkpoints. The correlative transcription factors and miRNAs of CBX3-binding hub genes were analyzed to investigate the molecular mechanism. Moreover, alcoholism and alteration of DNA cellular biology may be involved in the functional mechanisms of CBX3.

Conclusion

The first pan-cancer study offers a relatively comprehensive cognition on the oncogenic roles of CBX3 as a prognostic and immunological marker in various malignant tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01179-y.

CBX3 is associated with metastasis and glutathione/glycosphingolipid metabolism in colon adenocarcinoma

BACKGROUND

Metastasis is the major cause of colon adenocarcinoma (COAD) mortality. Increasing studies demonstrated that the epigenetics and downstream expression change of pivotal genes may act as a major role in promoting COAD progression and metastasis. Therefore, identifying the dysregulation of key genes associating with COAD metastasis may provide a new strategy for the discovery of potential treatment targets.

METHODS

This study included a single-cell RNA sequencing profile consisting of 17,469 tumor cells derived from 23 samples, and 326 COADs available from The Cancer Genome Atlas (TCGA), etc. The study was performed using comparative analysis to characterize the role of CBX3 in COAD metastasis and progression.

RESULTS

This study revealed that the mRNA level of Chromebox homolog 3 (CBX3) in the metastatic COAD was significantly higher than that of the primary COAD and normal colon tissues (Wilcoxon's rank-sum test, P<0.05). Activation of CBX3 was involved in regulating an interaction network consisting of CCT6A, LSM5, and GGCT, etc., which may subsequently participate in glutathione metabolism. Besides, CBX3 also exhibited a negative correlation with glycosphingolipid metabolism, which may associate with the regulation of CBX3 on DNA methylation. Clinical data analysis demonstrated that patients with high CBX3 mRNA levels showed a nearly 2-fold shorter overall survival time than the control group (hazard ratio =1.59; likelihood ratio test, P=0.04).

CONCLUSIONS

Our study demonstrated that CBX3 overexpression is associated with COAD metastasis. CBX3 downstream regulation network involves in TCP1 complex, LSM family, and glutathione metabolism, which may provide a potential target for suppressing tumor metastasis.

Heterochromatin Protein 1: A Multiplayer in Cancer Progression

Dysregulation of epigenetic mechanisms as well as genomic mutations contribute to the initiation and progression of cancer. In addition to histone code writers, including histone lysine methyltransferase (KMT), and histone code erasers, including histone lysine demethylase (KDM), histone code reader proteins such as HP1 are associated with abnormal chromatin regulation in human diseases. Heterochromatin protein 1 (HP1) recognizes histone H3 lysine 9 methylation and broadly affects chromatin biology, such as heterochromatin formation and maintenance, transcriptional regulation, DNA repair, chromatin remodeling, and chromosomal segregation. Molecular functions of HP1 proteins have been extensively studied, although their exact roles in diseases require further study. Here, we comprehensively review the studies that have revealed the altered expression of HP1 and its functions in tumorigenesis. In particular, the distinctive effects of each HP1 subtype, namely HP1α, HP1β, and HP1γ, have been thoroughly explored in various cancer types. We also highlight how HP1 can serve as a potential biomarker for cancer prognosis and therapeutic target for cancer patients.

Comprehensive bioinformatics analysis of functional molecules in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the 3rd most common cancer and the 2nd leading cause of cancer-related death. Numerous studies have found that aberrations in cellular molecules play an important role in the development of tumors. Studying and determining the interactions between these molecules can contribute to the diagnosis, treatment, and prognosis of tumors.

METHODS

The GSE151021, GSE156720, and GSE156719 data sets were analyzed to screen the differentially expressed messenger RNAs (DEmRNAs), long non-coding RNAs (DElncRNAs), and microRNAs (DEmiRNAs) in CRC. Database for Annotation, Visualization and Integrated Discovery (DAVID) and the Search Tool for the Retrieval of Interacting Genes/Proteins software were used to examine gene enrichment and the hub genes. Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and UALCAN was used to verify the expression of the hub genes. To analyze the overall survival (OS) of the hub genes, Kaplan-Meier plotter (KM plotter) was performed. Finally, the miRCancer database, TargetScan, and GSE156719 were used to identify the targets of the identified miRNAs. To predict the lncRNA-miRNA interactions, we used DIANA-LncBase v2 and GSE156720. Finally, the visualization protein‑protein interaction (PPI), competitive endogenous RNA (ceRNA) network was constructed using Cytoscape v3.1.

RESULTS

By analyzing GSE151021 and GSE156720, 23 upregulated mRNAs and 10 downregulated mRNAs were identified as sharing the differentially expressed genes (DEGs) between CRC and adjacent tissues. Furthermore, nucleolar protein 14 (NOP14), the sonic hedgehog (SHH) signaling molecule, phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1), the BCL2 apoptosis regulator (BCL2), and zinc finger E-box binding homeobox 2 (ZEB2) were considered hub genes. The constructed lncRNA-miRNA-mRNA network revealed 7 intersecting miRNAs (4 upregulated and 3 downregulated), 79 lncRNAs (40 upregulated and 39 downregulated), and 5 mRNAs (3 upregulated and 2 downregulated). Finally, we determined that the dysregulation of lncRNAs, such as HCG16, CASC9, SNHG16, HAND2-AS1, and NR2F1-AS1, secluded altered the expression of several miRNAs, such as hsa-miR-193a-5p, hsa-miR-485-5p, hsa-miR-17-5p, and hsa-miR-92a-3p, and affected the occurrence and development of CRC.

CONCLUSIONS

We identified a series of DElncRNAs, DEmRNAs, and DEmiRNAs in CRC that might be considered potential biomarkers in understanding the complex molecular pathways leading to CRC development.

Prognostic Value and Therapeutic Potential of CBX Family Members in Ovarian Cancer

Background: Ovarian cancer (OV) is one of the common malignant tumors and has a poor prognosis. Chromobox (CBX) family proteins are critical components of epigenetic regulation complexes that repress target genes transcriptionally via chromatin modification. Some studies have investigated the function specifications among several CBXs members in multiple cancer types, however, little is known about the functions and prognostic roles of distinct CBXs family proteins in ovarian cancer.

Methods: In this study, several bioinformatics databases and in vitro experiments were used to analyze the expression profiles, prognostic values, and therapeutic potential of the CBXs family (CBX1-8) in ovarian cancer.

Results: It was found that higher expression of CBX3/8 and lower expression of CBX1/6/7 were detected in OV tissues. CBX2/4/5/8 were significantly correlated with individual cancer stages of OV. The expression of CBX1/2/3 were all significantly associated with worse overall survival (OS) and progression-free survival (PFS) for OV patients, whereas the expression of other five CBXs members showed either irrelevant (CBX5 and CBX8) or inconsistent (CBX4, CBX6, and CBX7) results for both OS and PFS in OV. These results showed that only CBX3 had consistent results in expression and prognosis. Further cell experiments also showed that CBX3 promoted the proliferation of ovarian cancer cells. CBX3 was highly expressed in chemoresistant OV tissues. These results indicated that CBX3 was the most likely prognostic indicator and new therapeutic target in OV. Furthermore, gene enrichment analysis suggests that the CBXs family was primarily involved in mast cell activation and mast cell mediated immunity. Individual CBXs members were associated with varying degrees of the infiltration of immune cells, especially B cells. Finally, a high genetic alteration rate of CBXs family (39%) was observed in OV. The low methylation status of CBX3/8 in OV may be associated with their high expression levels.

Conclusions: Taken together, these findings exhibited the pivotal value of CBXs family members (especially CBX3) in the prognosis and chemoresistance of ovarian cancer. Our results may provide new insight to explore new prognostic biomarkers and therapeutic targets for ovarian cancer.

Bioinformatic Analysis of Prognostic Value, Genetic Interaction, and Immune Infiltration of Chromobox Family Proteins in Breast Cancer

Introduction

Breast cancer (BC) has become the malignant tumor with the highest incidence worldwide. As a critical components of epigenetic regulation complexes, chromobox (CBX) family members inhibit the transcription of target genes through chromatin modification, leading to the progression of various human diseases and cancers. So far, little is known about the role of different CBX members in BC, especially their association with immune cells.

Methods

We conducted the analysis of differential expression of CBXs using Oncomine and GEPIA, prognostic value of CBXs using GEPIA and Kaplan-Meier, genetic interaction of CBXs using cBioPortal and GeneMANIA, and immune cell infiltration of CBXs in BC patients using TIMER.

Results

The CBX2/3/4/8 expression levels were increased significantly, while the CBX6/7 expression levels were decreased. We found that CBX3 was significantly correlated with clinicopathological staging and short DFS in BC patients. High CBX3/5 expression was correlated with short OS in BC patients, while high expression of CBX4 was correlated with long OS in BC patients. In addition, the functions of CBXs family members mainly focus on methylated histone residue binding and chromatin organization. The CBXs expressions were closely related to the infiltration level of a variety of immune cells, including CD4/8+ T cells, B cells, neutrophils, macrophages and dendritic cells in BC cancers. The correlation between CBXs and immune cell infiltration was more common in Luminal BC than in Basal and Her-2 type.

Conclusion

This study may provide a new understanding for selection of molecular typing, therapeutic and prognostic biomarkers of CBX family in BC.

Prognostic and immune infiltrates for the Chromobox (CBX) protein family in human pancreatic adenocarcinoma

Background

Globally, pancreatic adenocarcinoma (PAAD) is among the most prevalent malignant tumors. The Chromobox (CBX) protein family is a vital component of epigenetic regulatory complexes that have vital biological roles. The biological functions, immune infiltration, expression levels, and the prognostic significance of CBX proteins in PAAD have not yet been established.

Methods

Using bioinformatics tools, such as the Gene Expression Profiling Interactive Analysis (GEPIA), Oncomine, Kaplan-Meier plotter, GeneMANIA, cBioPortal, TIMER and R, we evaluated the prognostic importance, expression levels, gene alterations, risk factors, and immune cell infiltration levels of CBXs in PAAD patients. The expression levels of CBX3 in clinical-pathological samples were also confirmed by immunohistochemistry.

Results

In PAAD tissues, CBX1, CBX3, CBX5, and CBX8 expressions were high. High CBX1, CBX5, CBX6, and CBX7 levels were correlated with tumor stages. Elevated CBX2, CBX6, CBX7, and CBX8 messenger ribonucleic acid (mRNA) levels were markedly correlated with better overall survival (OS) outcomes for pancreatic cancer patients, while elevated CBX3 was markedly correlated with short OS outcomes. In particular, we have validated the differential expression of CBX3 on clinical specimens using immunohistochemical methods. A multivariate logistic analysis revealed that elevated mRNA expression levels of CBX3 and suppressed CBX8 levels were independently associated with short OS outcomes for pancreatic cancer patients. The roles of CBXs and their neighboring proteins are associated with a negatively regulated cell cycle, histone binding, polycomb group protein complexes, and the regulation of pluripotent stem cell signaling pathways. Additionally, CBX levels were found to be markedly associated with immune infiltrates, and found that the immune infiltration score of CBX3 was differentially expressed in cell lines such as CD8 T cells, NK cells, Mast cells and T helper cells.

Conclusions

CBX3/8 is a potential marker for prognostic outcomes in PAAD patients.

Comprehensive Analysis of the Expression and Prognosis Value of Chromobox Family Members in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) accounts for 80% of all renal cancers and has a poor prognosis. Chromobox (CBX) family protein expression has been reported in a variety of human malignancies, but the roles of CBXs in ccRCC remain unclear. In this study, by using ONCOMINE, UALCAN, GEPIA, Kaplan-Meier Plotter, cBioPortal, and TIMER, we found the transcriptional levels of CBX3 and CBX4 in ccRCC tissues were significantly higher than those in normal kidney tissues, whereas the transcriptional levels of CBX1, CBX5, CBX6, and CBX7 were significantly reduced in ccRCC tissues. The promoters of CBX2, CBX3, CBX4, CBX5, CBX6, CBX7, and CBX8 were hypermethylated, whereas the CBX1 promoter was hypomethylated in ccRCC. The expression of CBX1, CBX3, CBX4, CBX5, CBX6, and CBX7 was significantly associated with clinicopathological parameters in ccRCC patients. ccRCC patients with high expression levels of CBX3, CBX4, and CBX8 and low expression levels of CBX1, CBX5, CBX6, and CBX7 showed a strong association with poor overall survival. Genetic alterations in CBXs were correlated with poor overall survival and disease-free survival in patients with ccRCC. Moreover, we found significant associations between the expression of CBXs and infiltration of immune cells (B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells). Our results provide novel insights into the development of CBX-based biomarkers and therapeutic targets for ccRCC.