Heterochromatin Protein HP1γ Promotes Colorectal Cancer Progression and Is Regulated by miR-30a

Tensin 4 facilitates aerobic glycolysis, migration and invasion of colorectal cancer cells through the β‑catenin/c‑Myc signaling pathway

Tensin 4 (TNS4) is overexpressed in multiple cancers, including colorectal cancer (CRC), and is associated with a poor prognosis of patients with CRC. However, the role and underlying mechanisms of TNS4 in CRC have yet to be elucidated. The expression of TNS4 in CRC tissues were analyzed by immunohistochemistry. Cell migration and invasion were assessed in vitro using Transwell assay. Western blot and reverse transcription (RT)-quantitative (q)PCR were used to investigate the molecular mechanisms by which TNS4 regulates aerobic glycolysis, migration and invasion of CRC cells. The present study demonstrated that TNS4 was highly expressed in the cancer tissues of patients with CRC and significantly associated with the tumor-node-metastasis stages. TNS4 silencing led to a significant decrease in glucose consumption and lactate production in CRC cells, and knockdown of TNS4 suppressed the migration and invasion of CRC cells via aerobic glycolysis through the β-catenin/c-Myc pathway. Notably, treatment with DASA-58, an activator of glycolysis, or SKL2001, an activator of β-catenin/c-Myc signaling, significantly reversed the effect of TNS4 knockdown on aerobic glycolysis, migration and invasion of CRC cells. Collectively, these results suggest that TNS4 may act as a novel regulator of aerobic glycolysis, migration and invasion of CRC cells by modulating β-catenin/c-Myc signaling, providing a new potential biomarker and therapeutic target in CRC.

The epigenetic landscape in intestinal stem cells and its deregulation in colorectal cancer

Epigenetic mechanisms play a pivotal role in controlling gene expression and cellular plasticity in both normal physiology and pathophysiological conditions. These mechanisms are particularly important in the regulation of stem cell self-renewal and differentiation, both in embryonic development and within adult tissues. A prime example of this finely tuned epigenetic control is observed in the gastrointestinal lining, where the small intestine undergoes renewal approximately every 3-5 days. How various epigenetic mechanisms modulate chromatin functions in intestinal stem cells (ISCs) is currently an active area of research. In this review, we discuss the main epigenetic mechanisms that control ISC differentiation under normal homeostasis. Furthermore, we explore the dysregulation of these mechanisms in the context of colorectal cancer (CRC) development. By outlining the main epigenetic mechanisms contributing to CRC, we highlight the recent therapeutics development and future directions for colorectal cancer research.

MicroRNA‑1224 inhibits cell proliferation by downregulating CBX3 expression in chordoma

MicroRNAs (miRNAs/miRs) have abnormal expression in numerous tumors and are closely related to tumor development and resistance to radiotherapy and chemotherapy. However, there are few studies assessing the role and mechanism of miRNA in chordoma. The sequencing data of three pairs of chordoma and notochord tissues from the GSE56183 dataset were analyzed in the present study. Cell proliferation was assessed in vitro using Cell Counting Kit-8. Bioinformatics analysis and the dual luciferase reporter assay were used to evaluate the regulatory relationship between miR-1224 and chromobox 3 (CBX3) in chordoma. The results demonstrated that miR-1224 had a significantly lower expression level in chordoma tissues and cell lines. Overexpression of miR-1224 inhibited proliferation in the chordoma cells, while the knockdown of miR-1224 promoted proliferation of the chordoma cells. Bioinformatics analysis and the dual luciferase reporter assay confirmed that CBX3 was a direct target gene of miR-1224 and that miR-1224 induced the proliferation of chordoma cells through the inhibition of CBX3. In summary, miR-1224 reduced the proliferation of chordoma cells through inhibition of CBX3, which provides a theoretical basis for selecting a novel therapeutic target for chordoma.

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.

Investigation of the potential of miRNA candidates as non-invasive biomarkers for the diagnosis and follow-up of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer worldwide, and despite advances in treatment, molecular biomarkers are needed for both early diagnosis and prognosis monitoring. It is known that microRNAs (miRNA), one of the epigenetic mechanisms, are effective in the initiation and development of cancer by regulating the activity of tumor suppressors and/or oncogenes. In this study, the potential of the molecules let-7, miRNA125b, and miRNA30a, which are known to play a role in cellular processes, as biomarkers for colorectal cancer and their molecular mechanisms were investigated in this model. The aim was to evaluate the diagnostic, prognostic, and predictive utility of the target miRNAs in colorectal cancer patients.

MATERIAL AND METHODS

The expression changes of miRNAs let-7, miRNA125b, and miRNA30a were investigated by miRNAs isolation and cDNA synthesis from the serum samples of 60 patients diagnosed with CRC or from the serum samples of 20 healthy individuals. The calculation was performed using the quantitative real-time polymerase chain reaction method to determine the expression level. The results were compared with clinical parameters.

RESULT

An 8-fold decrease in the expression of let-7 and miRNA125b and a 60-fold decrease in the expression of miRNA30a were found in the serum samples of patients diagnosed with colorectal cancer (CRC) compared to the healthy group. A decrease in let-7 was observed in 53.3%, miRNA125b in 58.3%, and miRNA30a in 55% of patients. A significant correlation was found between the reduced expression status and the stage, lymph nodes, local recurrence, and metastasis (p < 0.05). The ROC analysis showed that the miRNA30a level could be a diagnostic biomarker for CRC (p < 0.001). No significant impact of target miRNA expression changes on overall disease survival was observed.

CONCLUSION

It is thought that the target miRNA30a can be used for early diagnosis and screening and that the target miRNA let-7, miRNA125b, and miRNA30a can be used as non-invasive biomarkers for disease follow-up, with larger patient studies being conducted on CRC patients.

m5C modification of LINC00324 promotes angiogenesis in glioma through CBX3/VEGFR2 pathway

Angiogenesis plays a major role in tumor initiation, progression, and metastasis. This is why finding antiangiogenic targets is essential in the treatment of gliomas. In this study, NSUN2 and LINC00324 were significantly upregulated in conditionally cultured glioblastoma endothelial cells (GECs). Knockdown of NSUN2 or LINC00324 inhibits GECs angiogenesis. NSUN2 increased the stability of LINC00324 by m5C modification and upregulated LINC00324 expression. LINC00324 competes with the 3'UTR of CBX3 mRNA to bind to AUH protein, reducing the degradation of CBX3 mRNA. In addition, CBX3 directly binds to the promoter region of VEGFR2, enhances VEGFR2 transcription, and promotes GECs angiogenesis. These findings demonstrated NSUN2/LINC00324/CBX3 axis plays a crucial role in regulating glioma angiogenesis, which provides new strategies for glioma therapy.

DPY30 promotes colorectal carcinoma metastasis by upregulating ZEB1 transcriptional expression

DPY30 belongs to the core subunit of components of the histone lysine methyltransferase complex, which is implicated in tumorigenesis, cell senescence, and other biological events. However, its contribution to colorectal carcinoma (CRC) progression and metastasis has yet to be elucidated. Therefore, this study aimed to investigate the biological function of DPY30 in CRC metastasis both in vitro and in vivo. Herein, our results revealed that DPY30 overexpression is significantly positively correlated with positive lymph nodes, epithelial-mesenchymal transition (EMT), and CRC metastasis. Moreover, DPY30 knockdown in HT29 and SW480 cells markedly decreased EMT progression, as well as the migratory and invasive abilities of CRC cells in vitro and lung tumor metastasis in vivo. Mechanistically, DPY30 increased histone H3K4me3 level and promoted EMT and CRC metastasis by upregulating the transcriptional expression of ZEB1. Taken together, our findings indicate that DPY30 may serve as a therapeutic target and prognostic marker for CRC.

B7H3 increases ferroptosis resistance by inhibiting cholesterol metabolism in colorectal cancer

Ferroptosis, a newly discovered form of regulated cell death, has been reported to be associated with multiple cancers, including colorectal cancer (CRC). However, the underlying molecular mechanism is still unclear. In this study, we identified B7H3 as a potential regulator of ferroptosis resistance in CRC. B7H3 knockdown decreased but B7H3 overexpression increased the ferroptosis resistance of CRC cells, as evidenced by the expression of ferroptosis-associated genes (PTGS2, FTL, FTH, and GPX4) and the levels of important indicators of ferroptosis (malondialdehyde, iron load). Moreover, B7H3 promoted ferroptosis resistance by regulating sterol regulatory element binding protein 2 (SREBP2)-mediated cholesterol metabolism. Both exogenous cholesterol supplementation and treatment with the SREBP2 inhibitor betulin reversed the effect of B7H3 on ferroptosis in CRC cells. Furthermore, we verified that B7H3 downregulated SREBP2 expression by activating the AKT pathway. Additionally, multiplex immunohistochemistry was carried out to show the expression of B7H3, prostaglandin-endoperoxide synthase 2, and SREBP2 in CRC tumor tissues, which was associated with the prognosis of patients with CRC. In summary, our findings reveal a role for B7H3 in regulating ferroptosis by controlling cholesterol metabolism in CRC.

Deregulation of All-Trans Retinoic Acid Signaling and Development in Cancer

Cancer stem cells are the root cause of cancer, which, in essence, is a developmental disorder. All-trans retinoic acid (ATRA) signaling via ligand-activation of the retinoic acid receptors (RARs) plays a crucial role in tissue patterning and development during mammalian embryogenesis. In adults, active RARγ maintains the pool of hematopoietic stem cells, whereas active RARα drives myeloid cell differentiation. Various findings have revealed that ATRA signaling is deregulated in many cancers. The enzymes for ATRA synthesis are downregulated in colorectal, gastric, lung, and oropharyngeal cancers. ATRA levels within breast, ovarian, pancreatic, prostate, and renal cancer cells were lower than within their normal counterpart cells. The importance is that 0.24 nM ATRA activates RARγ (for stem cell stemness), whereas 100 times more is required to activate RARα (for differentiation). Moreover, RARγ is an oncogene regarding overexpression within colorectal, cholangiocarcinoma, hepatocellular, ovarian, pancreatic, and renal cancer cells. The microRNA (miR) 30a-5p downregulates expression of RARγ, and miR-30a/miR-30a-5p is a tumor suppressor for breast, colorectal, gastric, hepatocellular, lung, oropharyngeal, ovarian, pancreatic, prostate, and renal cancer. These complementary findings support the view that perturbations to ATRA signaling play a role in driving the abnormal behavior of cancer stem cells. Targeting ATRA synthesis and RARγ has provided promising approaches to eliminating cancer stem cells because such agents have been shown to drive cell death.

Pan-cancer analysis of Chromobox (CBX) genes for prognostic significance and cancer classification

Polycomb group of proteins play a significant role in chromatin remodelling essential for epigenetic regulation of transcription. Chromobox (CBX) gene family is an important part of canonical polycomb repressive complex 1 (PRC1), belonging to the polycomb group involved in chromatin remodelling. Aberrations in CBX expression are linked to various cancers. To assess their biomarker significance, we performed a pan-cancer analysis of CBX mRNA levels in 18 cancer types. We also performed cancer classification using CBX genes as distinctive features for machine learning model development. Logistic regression (L.R.), support vector machine (SVM), random forest (R.F.), decision tree (D.T.), and XGBoost (XGB) algorithms for model training and classification. The expression of CBX genes was significantly changed in four cancer types, i.e., cholangiocarcinoma (CHOL), colon adenocarcinoma (COAD), lung adenocarcinoma (LUAD), and lung squamous cell carcinoma (LUSC). The fold change (FC) values suggest that CBX2 was significantly upregulated in CHOL (FC = 1.639), COAD (FC = 1.734), and LUSC (FC = 1.506). On the other hand, CBX7 was found downregulated in COAD (FC = -1.209), LUAD (FC = -1.190), and LUSC (FC = -1.214). The performance of machine learning models for classification was excellent. L.R., R.F., SVM, and XGB obtained a prediction accuracy of 100 % for most cancers. However, D.T. performed comparatively poorly in prediction accuracy. The results suggest that CBX expression is significantly altered in all the cancers studied; therefore, they might be treated as potential biomarkers for therapeutic intervention of these cancers.

Mining Transcriptomic Data to Uncover the Association between CBX Family Members and Cancer Stemness

Genetic and epigenetic changes might facilitate the acquisition of stem cell-like phenotypes of tumors, resulting in worse patients outcome. Although the role of chromobox (CBX) domain proteins, a family of epigenetic factors that recognize specific histone marks, in the pathogenesis of several tumor types is well documented, little is known about their association with cancer stemness. Here, we have characterized the relationship between the CBX family members' expression and cancer stemness in liver, lung, pancreatic, and uterine tumors using publicly available TCGA and GEO databases and harnessing several bioinformatic tools (i.e., Oncomine, GEPIA2, TISIDB, GSCA, UALCAN, R2 platform, Enrichr, GSEA). We demonstrated that significant upregulation of CBX3 and downregulation of CBX7 are consistently associated with enriched cancer stem-cell-like phenotype across distinct tumor types. High CBX3 expression is observed in higher-grade tumors that exhibit stem cell-like traits, and CBX3-associated gene expression profiles are robustly enriched with stemness markers and targets for c-Myc transcription factor regardless of the tumor type. Similar to high-stemness tumors, CBX3-overexpressing cancers manifest a higher mutation load. On the other hand, higher-grade tumors are characterized by the significant downregulation of CBX7, and CBX7-associated gene expression profiles are significantly depleted with stem cell markers. In contrast to high-stemness tumors, cancer with CBX7 upregulation exhibit a lower mutation burden. Our results clearly demonstrate yet unrecognized association of high CBX3 and low CBX7 expression with cancer stem cell-like phenotype of solid tumors.

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.

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.

KCNK3 inhibits proliferation and glucose metabolism of lung adenocarcinoma via activation of AMPK-TXNIP pathway

Non-small cell lung cancer (NSCLC) is a primary histological subtype of lung cancer with increased morbidity and mortality. K⁺ channels have been revealed to be involved in carcinogenesis in various malignant tumors. However, TWIK-related acid-sensitive potassium channel 1 (TASK-1, also called KCNK3), a genetic member of K2P channels, remains an enigma in lung adenocarcinoma (LUAD). Herein, we investigated the pathological process of KCNK3 in proliferation and glucose metabolism of LUAD. The expressions of KCNK3 in LUAD tissues and corresponding adjacent tissues were identified by RNA sequencing, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry. Gain and loss-of-function assays were performed to estimate the role of KCNK3 in proliferation and glucose metabolism of LUAD. Additionally, energy metabolites of LUAD cells were identified by targeted metabolomics analysis. The expressions of metabolic molecules and active biomarkers associated with AMPK-TXNIP signaling pathway were detected via western blot and immunofluorescence. KCNK3 was significantly downregulated in LUAD tissues and correlated with patients' poor prognosis. Overexpression of KCNK3 largely regulated the process of oncogenesis and glycometabolism in LUAD in vitro and in vivo. Mechanistic studies found that KCNK3-mediated differential metabolites were mainly enriched in AMPK signaling pathway. Furthermore, rescue experiments demonstrated that KCNK3 suppressed proliferation and glucose metabolism via activation of the AMPK-TXNIP pathway in LUAD cells. In summary, our research highlighted an emerging role of KCNK3 in the proliferative activity and glycometabolism of LUAD, suggesting that KCNK3 may be an optimal predictor for prognosis and a potential therapeutic target of LUAD.

Chromobox 7/8 serve as independent indicators for glioblastoma via promoting proliferation and invasion of glioma cells

Background

The chromobox family, a critical component of epigenetic regulators, participates in the tumorigenesis and progression of many malignancies. However, the roles of the CBX family members (CBXs) in glioblastoma (GBM) remain unclear.

Methods

The mRNA expression of CBXs was analyzed in tissues and cell lines by Oncomine and Cancer Cell Line Encyclopedia (CCLE). The differential expression of CBXs at the mRNA level was explored in The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases with the “beeswarm” R package. The protein expression of CBXs in GBM was further examined on Human Protein Atlas (HPA). The correlations between CBXs and IDH mutation and between CBXs and GBM subtypes were investigated in the TCGA portal and CGGA database with the “survminer” R package. The alteration of CBXs and their prognostic value were further determined via the cBioPortal and CGGA database with the “survival” R package. The univariate and multivariate analyses were performed to screen out the independent prognostic roles of CBXs in the CGGA database. Cytoscape was used to visualize the functions and related pathways of CBXs in GBM. U251 and U87 glioma cells with gene intervention were used to validate the role of CBX7/8 in tumor proliferation and invasion. Proliferation/invasion-related markers were conducted by Western blot and immunostaining.

Results

CBXs presented significantly differential expressions in pan-cancers. CBX2/3/5/8 were upregulated, whereas CBX6/7 were downregulated at mRNA level in GBM of TCGA and CGGA databases. Similarly, high expression of CBX2/3/5 and low expression of CBX6/8 were further confirmed at the protein level in the HPA. CBX2/6/7 were positively correlated with IDH mutation and CBX1/2/4/5/8 were closely related to GBM subtypes. CBX7 and CBX8 presented the independent prognostic factors for GBM patient survival. GO and KEGG analyses indicated that CBXs were closely related to the histone H3-K36, PcG protein complex, ATPase, and Wnt pathway. The overexpression of CBX7 and underexpression of CBX8 significantly inhibited the proliferation and invasion of glioma cells in vivo and in vitro.

Conclusion

Our results suggested that CBX7 and CBX8 served as independent prognostic indicators that promoted the proliferation and invasion of glioma cells, providing a promising strategy for diagnosing and treating GBM.

Analysis of Pan-Cancer Revealed the Immunological and Prognostic Potential of CBX3 in Human Tumors

Chromobox protein homolog 3 (CBX3) has been recognized as a member of the heterochromatin protein 1 family and participate in transcriptional activation or inhibition, cell differentiation and growth. Despite more and more evidence shows that CBX3 has a critical function in the development of some tumors, no systematic extensive analysis of CBX3 has been reported. Thus, we intended to examine the prognostic significance of CBX3 in 33 tumors and investigate its potential immune function. We employed several bioinformatics methods to explore the potential carcinogenic impact of CBX3 premised on the data sets collected from tumor genome maps, human protein maps, cBioPortal, and genotype tissue expression. The approaches include assessing the link between CBX3 and prognosis of different tumors, immune cell infiltration, micro-satellite instability (MSI), DNA methylation, and tumor mutational burden (TMB). The outcomes illustrated that CBX3 was increasingly expressed in 29 tumors. Moreover, CBX3 exhibited a negative correlation with the prognosis of many tumors. The expression of CBX3 was linked to MSI in 12 tumors and TMB in 16 tumors. In 24 tumors, the expression of CBX3 was linked to DNA methylation. Moreover, the CBX3 expression exhibited a negative relationship with the infiltration level of the majority of immune cells, but showed a positive link to T gamma delta cells, central memory T cells, and T helper cells, especially when invading breast carcinoma, thymic carcinoma, colon carcinoma, cutaneous melanoma, endometrial carcinoma, and lung squamous carcinoma. Our research indicates that CBX3 might be used as a prognostic indicator for different malignant tumors due to its function in tumor genesis as well as tumor immunity.

CBX3 regulated by miR-139 promotes the development of HCC by regulating cell cycle progression

Hepatocellular carcinoma (HCC), a major primary liver cancer, is one of the most lethal malignancies worldwide. Increasing evidence has demonstrated that chromobox protein homolog 3 (CBX3) functions as an oncogene in different cancers. However, its expression profiles and biological functions in HCC remain unknown. Data on CBX3 expression in HCC acquired from the GEO and TCGA databases were analyzed. The biological functions of CBX3 in HCC were examined by in vitro experiments. Bioinformatics analysis, qRT-PCR and western blotting were performed to explore the mechanism of CBX3 in HCC. CBX3 mRNA was upregulated in HCC tissues, and overexpression of CBX3 mRNA was negatively correlated with malignancies and poor prognosis in HCC patients. CBX3 knockdown decreased growth, migration and invasion of HCC cells in vitro. Moreover, bioinformatics analysis and experimental observation indicated that CBX3 expression was correlated with cell cycle regulatory proteins in HCC cells. Finally, starBase predicted that miR-139 could directly target CBX3 in HCC. Confirmatory experiments verified that miR-139 overexpression attenuated HCC cell proliferation and migration, and these effects could be reversed by overexpressing CBX3. Our results showed that the miR-139/CBX3 axis may be involved in HCC development by regulating cell cycle progression and may be a promising target in the treatment of HCC.

CBX3 accelerates the malignant progression of glioblastoma multiforme by stabilizing EGFR expression

CBX3, also known as HP1γ, is a major isoform of heterochromatin protein 1, whose deregulation has been reported to promote the development of human cancers. However, the molecular mechanism of CBX3 in glioblastoma multiforme (GBM) are unclear. Our study reported the identification of CBX3 as a potential therapeutic target for GBM. Briefly, we found that, CBX3 is significantly upregulated in GBM and reduces patient survival. In addition, functional assays demonstrated that CBX3 significantly promote the proliferation, invasion and tumorigenesis of GBM cells in vitro and in vivo. Mechanistically, Erlotinib, a small molecule targeting epidermal growth factor receptor (EGFR) tyrosine kinase, was used to demonstrate that CBX3 direct the malignant progression of GBM are EGFR dependent. Previous studies have shown that PARK2(Parkin) and STUB1(Carboxy Terminus of Hsp70-Interacting Protein) are EGFR-specific E3 ligases. Notably, we verified that CBX3 directly suppressed PARK2 and STUB1 at the transcriptional level through its CD domain to reduce the ubiquitination of EGFR. Moreover, the CSD domain of CBX3 interacted with PARK2 and regulated its ubiquitination to further reduce its protein level. Collectively, these results revealed an unknown mechanism underlying the pathogenesis of GBM and confirmed that CBX3 is a promising therapeutic target.

LINC01006 regulates the proliferation, migration and invasion of hepatocellular carcinoma cells through regulating miR-433-3p/CBX3 axis

INTRODUCTION AND OBJECTIVES

LINC01006 has been verified to be correlated with several cancer types, whereas its biological function in hepatocellular carcinoma (HCC) is still elusive. This study aimed to elucidate the specific regulatory mechanism of LINC01006 in the tumorigenesis of HCC.

MATERIALS AND METHODS

The expression of LINC01006, miR-433-3p and CBX3 in HCC tissues and cells was assessed by qRT-PCR or Western blot. MTT, wound-healing, and transwell assays were used to evaluate the effects of LINC01006 on cell viability, migration, and invasion in vitro. A mouse xenograft model was established for in vivo assays. The relations among LINC01006, miR-433-3p, and CBX3 were analyzed by MS2-RNA immunoprecipitation (RIP) and Dual-luciferase reporter (DLR) assays.

RESULTS

The expression of LINC01006 was up-regulated in HCC tissues and cells. LINC01006 knockdown inhibited the viability, wound healing rate, and invasive cell number of HeP3B and SK-HeP-1 cells, and decreased the tumor volume and weight in a mouse xenograft model. MiR-433-3p was a target of LINC01006, and LINC01006 overexpression inhibited the viability, wound healing rate, and invasive cell number of HeP3B and SK-HeP-1 cells. In addition, CBX3 was a target of miR-433-3p, which was negatively regulated by miR-433-3p. CBX3 overexpression and miR-433-3p inhibition reversed the inhibiting effects of LINC01006 knockdown on the viability, migration, and invasion of HeP3B cells.

CONCLUSIONS

Silencing of LINC01006 inhibited the viability, migration, and invasion of HCC cells through regulating miR-433-3p/CBX3 axis.

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.

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.

Clinicopathological significance of CBX3 in colorectal cancer: An intensive expression study based on formalin-fixed and paraffin-embedded tissues

CBX3 is an isoform of the heterochromatin protein 1 family, which is involved in carcinogenesis and promotes the progression of certain types of cancer. The expression level and clinicopathological significances of CBX3 in colorectal cancer (CRC) are still not well reported. In this study, we examined CBX3 protein expression in formalin-fixed and paraffin-embedded normal mucosae, hyperplastic polyps, low-and high-grade adenomas, and CRC tissue samples using immunohistochemistry. The associations of CBX3 expression levels with clinicopathological parameters, mismatch repair (MMR) protein expression, and kirsten rat sarcoma viral oncogene homolog (KRAS) and B-raf proto-oncogene (BRAF) mutations were analyzed. Our results showed that CBX3 protein was negatively expressed in normal mucosae and hyperplastic polyps, as well as in most low-grade adenomas. Interestingly, CBX3 protein was positively expressed in most high-grade adenomas and CRC tissues. CBX3 expression level was associated with tumor differentiation (p = 0.012), lymph node metastasis (p = 0.024), TNM stage (p = 0.008) and survival (p = 0.029). CBX3 expression was associated with MMR protein expression (p = 0.011) and KRAS mutation (p = 0.013), but not with BRAF mutation (p = 0.097). Our data suggest that CBX3 may be used as a molecular marker in CRC to evaluate tumor differentiation, lymph node metastasis, and pathological stage.

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.

ZRANB1 enhances stem-cell-like features and accelerates tumor progression by regulating Sox9-mediated USP22/Wnt/β-catenin pathway in colorectal cancer

The pathogenesis of colorectal cancer (CRC) is a multistep process characterized by the accumulation of gene mutations and epigenetic alterations. Tumor necrosis factor receptor-associated factor-binding protein domain (ZRANB1) is a deubiquitinase that mediates tumor growth and metastasis by deubiquitinating target proteins. In this study, we examined the regulatory effects of ZRANB1 on the maintenance of cancer stem cell (CSC) properties and tumor growth in CRC. Human CRC tissue samples and matched normal tissues were collected for the analysis of ZRANB1 expression. ZRANB1 was upregulated in CRC human tissues and cell lines, and its expression was positively correlated with advanced tumor stage and poor survival of CRC patients. The overexpression of ZRANB1 also induced the expression of CSC markers in CRC cells. Then, a xenograft model was established by inoculating BALB/c mice with CRC cells. The upregulation of ZRANB1 promoted tumorigenesis in vivo. Sox9 is a transcription factor that acts as an oncogene in human cancers. ZRANB1 increased the stability of Sox9 in CRC cells by decelerating its ubiquitination. Further analysis revealed that Sox9 regulated the transcription activity of USP22 by binding to its promoter. Moreover, ZRANB1 enhances stem-cell-like features of CRC cells and activated the Wnt/β-catenin pathway through USP22. Our results highlighted the role of ZRANB1 as a molecular target for CRC treatment, which may contribute to the development of novel therapies with better efficacy.

High-spatial and colourimetric imaging of histone modifications in single senescent cells using plasmonic nanoprobes

Histones are closely related to the state of chromatin, and epigenetic modification of their tail results in regulation in cells. Therefore, developing various analytical tools to map the changes in position and distribution of histone modifications is helpful in studying underlying mechanisms. Herein, we propose a high-spatial and colourimetric imaging method using plasmonic nanoparticles as probes to visualize heterochromatin histone markers in a single nucleus. We visualized the reorganization between repressive histone markers, H3K9me3 and H3K27me3, caused by oncogene-induced senescence based on the scattering colours and spectral shift of plasmonic nanoprobes to longer wavelengths using their distance-dependent coupling effect. The measured scattering profiles were correlated with the computation results simulating the scattering spectra according to the arrangements and distances among the plasmonic nanoprobes. The plasmonic nanoprobe-based high-spatial hyperspectral imaging provides an advanced way to study the dynamics of histone modifications for predicting the progression of diseases or senescence.

A Functional Polymorphism in Accessible Chromatin Region Confers Risk of Non-Small Cell Lung Cancer in Chinese Population

Background

The disease-associated non-coding variants identified by genome-wide association studies (GWASs) were enriched in open chromatin regions (OCRs) and implicated in gene regulation. Genetic variants in OCRs thus may exert regulatory functions and contribute to non-small cell lung cancer (NSCLC) susceptibility.

Objective

To fine map potential functional variants in GWAS loci that contribute to NSCLC predisposition using chromatin accessibility and histone modification data and explore their functions by population study and biochemical experimental analyses.

Methods

We mapped the chromatin accessible regions of lung tissues using data of assay for transposase-accessible chromatin using sequencing (ATAC-seq) in The Cancer Genome Atlas (TCGA) and prioritized potential regulatory variants within lung cancer GWAS loci by aligning with histone signatures using data of chromatin immunoprecipitation assays followed by sequencing (ChIP-seq) in the Encyclopedia of DNA Elements (ENCODE). A two-stage case–control study with 1,830 cases and 2,001 controls was conducted to explore the associations between candidate variants and NSCLC risk in Chinese population. Bioinformatic annotations and biochemical experiments were performed to further reveal the potential functions of significant variants.

Results

Sixteen potential functional single-nucleotide polymorphisms (SNPs) were selected as candidates from bioinformatics analyses. Three variants out of the 16 candidate SNPs survived after genotyping in stage 1 case–control study, and only the results of SNP rs13064999 were successfully validated in the analyses of stage 2 case–control study. In combined analyses, rs13064999 was significantly associated with NSCLC risk [additive model; odds ratio (OR) = 1.17; 95%CI, 1.07–1.29; p = 0.001]. Functional annotations indicated its potential enhancer bioactivity, and dual-luciferase reporter assays revealed a significant increase in luciferase activity for the reconstructed plasmid with rs13064999 A allele, when compared to the one with wild-type G allele (p_A549 < 0.001, p_SK-MES-1 = 0.004). Further electrophoretic mobility shift assays (EMSA) and super-shift assays confirmed a stronger affinity of HP1γ for the binding motif containing SNP rs13064999 A allele.

Conclusion

These findings suggested that the functional variant rs13064999, identified by the integration of ATAC-seq and ChIP-seq data, contributes to the susceptibility of NSCLC by affecting HP1γ binding, while the exact biological mechanism awaits further exploration.

Evaluation of the prognostic value of CBXs in gastric cancer patients

Chromobox (CBX) proteins were suggested to exert epigenetic regulatory and transcriptionally repressing effects on target genes and might play key roles in the carcinogenesis of a variety of carcinomas. Nevertheless, the functions and prognostic significance of CBXs in gastric cancer (GC) remain unclear. The current study investigated the roles of CBXs in the prognosis of GC using the Oncomine, The Gene Expression Profiling Interactive Analysis (GEPIA), UALCAN, The Cancer Genome Atlas (TCGA), and cBioPortal databases. CBX1/2/3/4/5 were significantly upregulated in GC tissues compared with normal tissues, and CBX7 was downregulated. Multivariate analysis showed that high mRNA expression levels of CBX3/8 were independent prognostic factors for prolonged OS in GC patients. In addition, the genetic mutation rate of CBXs was 37% in GC patients, and genetic alterations in CBXs showed no association with OS or disease-free survival (DFS) in GC patients. These results indicated that CBX3/8 can be prognostic biomarkers for the survival of GC patients.

Circular RNAs as novel potential biomarkers for pancreatic cancer

Pancreatic cancer (PaCa) is the fourth leading cause of cancer-related deaths in the United States, and the vast majority of these malignancies are pancreatic ductal adenocarcinomas (PDAC), but there is still a lack of early detection biomarkers for PaCa. Unlike linear RNAs, circRNAs form covalently closed continuous loops and can act as mammalian gene regulators. They may be diagnostic or predictive biomarkers for some tumors, also be novel potential therapeutic targets in different diseases. This review focuses on (1) the biogenesis of circRNAs, RNA binding proteins (RBPs) and complementary sequences of circRNAs; (2) the characteristics of circRNAs which allow them to interact with miRNAs; (3) the roles of circRNAs playing in the regulation of gene expression, cell behavior and cancer, and their potential role as novel biomarkers and therapeutic targets in pancreatic cancer.

Comprehensive Analysis of Genes Associated With Sudden Infant Death Syndrome

Background: Sudden infant death syndrome (SIDS) is a tragic incident which remains a mystery even after post-mortem investigation and thorough researches. Methods: This comprehensive review is based on the genes reported in the molecular autopsy studies conducted on SIDS so far. A total of 20 original studies and 7 case reports were identified and included in this analysis. The genes identified in children or adults were not included. Most of the genes reported in these studies belonged to cardiac channel and cardiomyopathy. Cardiac channel genes in SIDS were scrutinized for further analysis. Results: After screening and removing the duplicates, 42 unique genes were extracted. When the location of these genes was assessed, it was observed that most of these belonged to Chromosomes 11, 1 and 3 in sequential manner. The pathway analysis shows that these genes are involved in the regulation of heart rate, action potential, cardiac muscle cell contraction and heart contraction. The protein-protein interaction network was also very big and highly interactive. SCN5A, CAV3, ALG10B, AKAP9 and many more were mainly found in these cases and were regulated by many transcription factors such as MYOG C2C1 and CBX3 HCT11. Micro RNA, "hsa-miR-133a-3p" was found to be prevalent in the targeted genes. Conclusions: Molecular and computational approaches are a step forward toward exploration of these sad demises. It is so far a new arena but seems promising to dig out the genetic cause of SIDS in the years to come.

MiR-30a suppresses metastasis of gastric adenocarcinoma via targeting FAPα

BACKGROUND

Gastric cancer is one of the leading causes of death worldwide. MicroRNA-30a (miR-30a) has been demonstrated to be involved in several types of cancer development.

OBJECTIVE

We aimed to identify the molecular mechanism of miR-30a in gastric cancer.

METHODS

We investigated the expression of miR-30a in gastric cancer tissues by qRT-PCR. The role of miR-30a on the metastasis and proliferation of gastric cancer was evaluated by cell migration assay, CCK-8 assay and tumor peritoneal dissemination model. The target of miR-30a in gastric cancer was identified.

RESULTS

We discovered that miR-30a was significantly downregulated in gastric cancer tissues compared with adjacent nonmalignant tissues. The expression of miR-30a was inversely correlated with progression of gastric cancer. Gain- and loss-of function revealed that miR-30a acted as a potent tumor suppressor in gastric cancer. Re-expressed miR-30a inhibited gastric cancer cells migration, knock down miR-30a have the opposite effects. Furthermore, overexpression of miR-30a suppressed tumor peritoneal dissemination in vivo. We identified that fibroblast activation protein α (FAPα) was a direct target of miR-30a. The relative expression of FAPα was significantly higher in gastric cancer tissues compared with adjacent nonmalignant tissues. Inhibition of FAPα could recapitulate the effects of miR-30a, and overexpression of FAPα could abrogate the effect of miR-30a.

CONCLUSION

MiR-30a inhibited gastric cancer metastasis by targeting FAPα, suggesting that miR-30a may function as a novel tumor suppressor in gastric cancer.

Clinicopathological and Prognostic Significance of CBX3 Expression in Human Cancer: a Systematic Review and Meta-analysis

BACKGROUND

Chromebox protein homolog 3 (CBX3) as a member of the heterochromatin-associated protein 1 (HP1) family has been reported to be overexpressed in human cancer tissues. Numerous studies have shown the relationship between the CBX3 expression and clinicopathological factor or prognosis in malignant tumors, but their results are inconsistent. To address these results, a meta-analysis was described to investigate the prognostic value and clinicopathological significance of CBX3 expression in human malignant neoplasms.

METHODS

PubMed, Web of Science, Embase, and Chinese National Knowledge Infrastructure (CNKI) were used to search eligible literatures, including publications prior to September 2019. The role of CBX3 in cancer prognosis and clinicopathological characteristics was assessed by pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Eleven studies with 1682 cancer patients were enrolled in this meta-analysis. This analysis demonstrated that the patients' increased CBX3 expression was significantly associated with poor overall survival (OS) (univariate analysis: HR = 1.81, 95% CI 1.46-2.25; multivariate analysis: HR = 1.95, 95% CI 1.63-2.34). Subgroups analysis by tumor type also indicated that high expression of CBX3 was correlated with poor OS in tongue squamous cell carcinoma (HR = 3.31, 95% CI 2.03-5.39), lung cancer (HR = 1.66, 95% CI 1.21-2.29), genitourinary cancer (HR = 2.03, 95% CI 1.15-3.58), and digestive cancer (HR = 1.48, 95% CI 1.23-1.79). For clinicopathological features, high expression of CBX3 was associated with lymph node metastasis (OR = 2.96, 95% CI 1.42-6.20) and lager tumor size (OR = 1.60, 95% CI 1.12-2.28).

CONCLUSION

The results of this meta-analysis indicated that CBX3 expression may be a novel biomarker for predicting patient prognosis and clinicopathological parameters in multiple human cancer.

Identification of the Roles of Chromobox Family Members in Gastric Cancer: A Study Based on Multiple Datasets

Background

As the important components in polycomb repressive complexes 1 (PRC1) and heterochromatin protein 1 (HP1), Chromobox (CBX) family members are involved in epigenetic regulatory function, transcriptional repression, and other cellular metabolisms. Increasing studies have indicated significant associations between CBX and tumorigenesis, which is a progression in different types of cancers. However, the information about the roles of each CBX in gastric cancer is extremely limited.

Methods

We explored CBX mRNA expression, corrections with clinicopathological parameters, protein expression, prognostic values, enrichment analysis with several databases including Oncomine, Human Protein Atlas, UALCAN, Kaplan-Meier plotter, cBioPortal, GeneMANIA, and Enrichr.

Results

In our study, comparing to the normal tissues, higher mRNA expression of CBX1/2/3/4/5/8 and lower mRNA expression of CBX7 were found in GC tissues while upregulations of CBX1/2/3/4/5/8 and downregulations of CBX7 were indicated to be significantly correlated to the nodal metastasis status and individual cancer stages in GC patients. As for protein level, the expression of CBX2/3/4/5/6 was higher and the expression of CBX7 was lower in the GC tissues than those in the normal. What is more, higher mRNA expression of CBX1/5/6/8 and lower mRNA expression of CBX7 were markedly correlated to poor outcomes of OS and FP in GC patients. Besides, high mutation rate of CBXs (42%) was observed in GC patients.

Conclusions

We suggest that CBX5/7 may serve as potential therapeutic targets for GC while CBX1/8 may serve as potential prognostic indicators for GC.

B7-H3 regulates KIF15-activated ERK1/2 pathway and contributes to radioresistance in colorectal cancer

As an important modality for the local control of colorectal cancer (CRC), radiotherapy or neoadjuvant radiotherapy is widely applied in the clinic, but radioresistance has become a major obstacle for CRC radiotherapy. Here we reported that B7-H3, an important costimulatory molecule, is associated with radioresistance in CRC. The expression of B7-H3 was obviously increased in CRC cells after irradiation. The enhanced expression of B7-H3 promoted, while the knockdown of B7-H3 inhibited, colony formation and cell activity in CRC cells following radiation treatment. B7-H3 overexpression reduced S phase arrest and protected cell apoptosis induced by radiation, whereas B7-H3 knockdown had the opposite effects. In addition, B7-H3 blockade by 3E8, a specific B7-H3 antibody, significantly sensitized CRC cells to irradiation in vivo. Mechanistic analysis revealed that B7-H3 regulated KIF15 via RNA sequencing, which was in dependent of NF-κB pathway. And small interfering RNA (siRNA)-mediated KIF15 silencing or KIF15 blockade by the inhibitor SB743921 abolished the effect of B7-H3 on radioresistance in vitro and in vivo. Similar to B7-H3, we find that the protein expression levels of KIF15, which showed a positive correlation with B7-H3, was abnormal upregulated in cancer tissues than in adjacent normal tissues and associated with TNM stage. Finally, B7-H3/KIF15 enhanced resistance against irradiation in CRC cells via activating ERK1/2 signaling, a key pathway involved in radioresistance in cancer. Our findings reveal an alternative mechanism by which CRC cells can acquire radioresistance via the B7-H3/KIF15/ERK axis.

Diverse CBX family members as potential prognostic biomarkers in non-small-cell lung cancer

Chromobox (CBX) family members are vital epigenetic regulators that repress the transcription of target genes through chromatin modification. Several studies have investigated the role of CBX family members in cancer. However, the function and prognostic value of diverse CBX family members in non‐small‐cell lung cancer remain largely unknown. In this study, we reveal that CBX family members are overexpressed in non‐small‐cell lung cancer tissue compared with normal lung tissue, with the exception of CBX6. Kaplan–Meier analysis demonstrated that high expressions of CBX1 and CBX3 are correlated with overall survival, disease‐specific survival, disease‐free interval, and progression‐free interval for patients with lung adenocarcinoma (LUAD). Furthermore, regression model analysis suggests that CBX3 may be suitable as an independent prediction factor for overall survival and progression‐free interval in patients with LUAD. In addition, CBX3 mRNA expression was found to be associated with tumor diameter and lymph node metastasis. Gene enrichment analysis suggests that CBX3 is involved in the cell cycle and P53 signaling pathways. Aberrant expression of CBX3 in LUAD is correlated with DNA copy number alteration. In summary, our data imply that CBX3 plays an important role in the promotion of LUAD and may thus have potential as a prognostic biomarker and molecular therapeutic target for the disease.

The Value of Serum MicroRNA Expression Signature in Predicting Refractoriness to Bortezomib-Based Therapy in Multiple Myeloma Patients

Bortezomib is the first-in-class proteasome inhibitor, commonly used in the treatment of multiple myeloma (MM). The mechanisms underlying acquired bortezomib resistance in MM are poorly understood. Several cell-free miRNAs have been found to be aberrantly regulated in MM patients. The aim of this pilot study was to identify a blood-based miRNA signature that predicts bortezomib-based therapy efficacy in MM patients. Thirty MM patients treated with bortezomib-based regimens were studied, including 19 with refractory disease and 11 who were bortezomib sensitive. Serum miRNA expression patterns were identified with miRCURY LNA miRNA miRNome PCR Panels I+II (Exiqon/Qiagen). Univariate analysis found a total of 21 miRNAs to be differentially expressed in patients with MM according to bortezomib sensitivity. Multivariate logistic regression was created and allowed us to discriminate refractory from sensitive patients with a very high AUC of 0.95 (95%CI: 0.84-1.00); sensitivity, specificity and accuracy were estimated as 0.95, 0.91, and 0.93. The model used expression of 3 miRNAs: miR-215-5p, miR-181a-5p and miR-376c-3p. This study is the first to demonstrate that serum expression of several miRNAs differs between patients who are bortezomib refractory and those who are sensitive which may prove useful in studies aimed at overcoming drug resistance in MM treatment.

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

Objective: Colorectal cancer (CRC) is one of the common malignant tumors worldwide. Chromobox (CBX) family proteins are important components of epigenetic regulation complexes and are implicated in the development of multiple cancers by blocking differentiation and promoting proliferation. However, little is known about the function of distinct CBX proteins in colorectal cancer.

Methods: Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier plotter, cBioPortal, GeneMANIA, and TIMER were utilized to analyze differential expression, prognostic value, genetic alteration and immune cell infiltration of CBXs in colorectal cancer patients.

Results: The expression levels of CBX1/2/3/4/5 and CBX8 were significantly elevated in CRC tissues, whereas the expression levels of CBX6/7 were reduced. CBX3 was significantly associated with the clinical cancer stage and short disease-free survival (DFS) in CRC patients. High mRNA expression of CBX5/6 was associated with short overall survival (OS) in rectal cancer patients. CBX3/5/6 could be potential prognostic biomarkers for the survival of CRC patients. Moreover, the functions of the differentially expressed CBXs were primarily related to the SUMOylation of DNA methylation proteins and chromatin organization and may regulate the pluripotency of stem cells. The expression of CBXs were significantly correlated with the infiltration of diverse immune cells, including six types of CD4+ T cells, macrophages, neutrophils, B cells, CD8+ T cells, and dendritic cells in colon cancers and rectal cancers.

Conclusions: Our study may provide novel insights for the selection of prognostic biomarkers of CBX family in colorectal cancer.

HPV-mediated nuclear export of HP1γ drives cervical tumorigenesis by downregulation of p53

E6 oncoprotein derived from high-risk human papillomavirus (HPV) drives the development of cervical cancer through p53 degradation. Because cervical cancer therapies to inactivate HPV or E6 protein are not available, alternative strategies are required. Here, we show that HPV-mediated nuclear export of human heterochromatin protein 1γ (HP1γ) reduces the stability of p53 through UBE2L3-mediated p53 polyubiquitination during cervical cancer progression. In general, HP1 plays a key role in heterochromatin formation and transcription in the nucleus. However, our immunostaining data showed that the majority of HP1γ is localized in the cytoplasm in HPV-mediated cervical cancer. We found that HPV E6 protein drives unusual nuclear export of HP1γ through the interaction between the NES sequence of HP1γ and exportin-1. The mutation of the NES sequence in HP1γ led to nuclear retention of HP1γ and reduced cervical cancer cell growth and tumor generation. We further discovered that HP1γ directly suppresses the expression of UBE2L3 which drives E6-mediated proteasomal degradation of p53 in cervical cancer. Downregulation of UBE2L3 by overexpression of HP1γ suppressed UBE2L3-dependent p53 degradation-promoting apoptosis of cervical cancer cells. Our findings propose a useful strategy to overcome p53 degradation in cervical cancer through the blockage of nuclear export of HP1γ.

The Prognostic Value of the Chromobox Family in Human Ovarian Cancer

Ovarian cancer is one of the most lethal gynecologic tumors in women and has a poor prognosis. The purpose of our study was to identify new prognostic markers in ovarian cancer. We examined the prognostic roles of mRNA expression of the chromobox (CBX) family in patients with ovarian cancer utilizing the Kaplan-Meier plotter database. The prognostic values and expression levels of CBX members associated with prognosis were further evaluated using KM plotter in diverse subgroups and immunohistochemistry (IHC) analysis in ovarian carcinoma. The results revealed that elevated CBX1-3 mRNA expression may predict poor overall survival (OS) and progression-free survival (PFS) outcomes in patients with ovarian cancer. Notably, in women with ovarian cancer, increased CBX1 mRNA expression was linked to a short OS in all stages and in the grade II and grade III subgroups. Additionally, CBX2 and CBX3 were strongly related to short OS in stage III+IV patients, and a link between high CBX3 mRNA expression and unfavorable OS in grade II patients was observed. High expression levels of CBX1 and CBX3 were significantly associated with chemotherapy resistance in ovarian cancer patients. IHC staining showed that the CBX1-3 proteins were upregulated in serous ovarian carcinoma tissues compared with normal ovarian tissues. Therefore, our results indicated that CBX1-3 could be attractive biomarkers for predicting poor prognosis of ovarian cancer.

MiR-30a-5p inhibits proliferation and metastasis of hydatidiform mole by regulating B3GNT5 through ERK/AKT pathways

Hydatidiform moles are gestational trophoblastic disease. They are abnormal proliferations of trophoblast cells that have the potential to become cancerous. miR-miR30a-5p is a tumour suppressor that participates in the development of numerous diseases. However, the role of miR-30a in hydatidiform moles and the mechanisms underlying its effects are presently unclear. This study explored the levels of miR-30a and B3GNT5 expression in human hydatidiform mole tissue. The results showed that miR-30a and B3GNT5 were differentially expressed in normal placenta and hydatidiform mole, and miR-30a decreased cell proliferation, invasion and migration in trophoblast cell lines. Upon further examination, it was confirmed that miR-30a directly targeted the 3'untranslated region of B3GNT5 using a dual-luciferase assay. The results of the present study also revealed that miR-30a reduced the proliferation, invasion and migration ability in JAR and BeWo cells by regulating B3GNT5, which may inactivate the ERK and AKT signalling pathways. This study demonstrated that miR-30a was a novel target B3GNT5 that serves an important role in the development of hydatidiform moles, suggesting that miR-30a may serve as a novel potential biomarker or useful diagnostic and therapeutic tool for hydatidiform moles in clinical settings.

microRNA-30a arbitrates intestinal-type early gastric carcinogenesis by directly targeting ITGA2

BACKGROUND

Spasmolytic polypeptide-expressing metaplasia (SPEM) is considered a precursor lesion of intestinal metaplasia and intestinal-type gastric cancer (GC), but little is known about microRNA alterations during metaplasia and GC developments. Here, we investigate miR-30a expression in gastric lesions and identify its novel target gene which is associated with the intestinal-type GC.

METHODS

We conducted in situ hybridization and qRT-PCR to determine miR-30a expression in gastric tissues. miR-30a functions were determined through induction or inhibition of miR-30a in GC cell lines. A gene microarray was utilized to confirm miR-30a target genes in GC, and siRNA-mediated target gene suppression and immunostaining were performed. The Cancer Genome Atlas data were utilized to validate gene expressions.

RESULTS

We found down-regulation of miR-30a during chief cell transdifferentiation into SPEM. MiR-30a level was also reduced in the early stage of GC, and its level was maintained in advanced GC. We identified a novel target gene of miR-30a and ITGA2, and our results showed that either ectopic expression of miR-30a or ITGA2 knockdown suppressed GC cell proliferation, migration, and tumorigenesis. Levels of ITGA2 inversely correlated with levels of miR-30a in human intestinal-type GC.

CONCLUSION

We found down-regulation of miR-30a in preneoplastic lesions and its tumor-suppressive functions by targeting ITGA2 in GC. The level of ITGA2, which functions as an oncogene, was up-regulated in human GC. The results of this study suggest that coordination of the miR-30a-ITGA2 axis may serve as an important mechanism in the development of gastric precancerous lesions and intestinal-type GC.

Molecular classification of IDH-mutant glioblastomas based on gene expression profiles

Isocitrate dehydrogenase (IDH) mutant glioblastoma (GBM), accounts for ~10% GBMs, arises from lower grade diffuse glioma and preferentially appears in younger patients. Here, we aim to establish a robust gene expression-based molecular classification of IDH-mutant GBM. A total of 33 samples from the Chinese Glioma Genome Atlas RNA-sequencing data were selected as training set, and 21 cases from Chinese Glioma Genome Atlas microarray data were used as validation set. Consensus clustering identified three groups with distinguished prognostic and molecular features. G1 group, with a poorer clinical outcome, mainly contained TERT promoter wild-type and male cases. G2 and G3 groups had better prognosis differed in gender. Gene ontology analysis showed that genes enriched in G1 group were involved in DNA replication, cell division and cycle. On the basis of the differential genes between G1 and G2/G3 groups, a six-gene signature was developed with a Cox proportional hazards model. Kaplan-Meier analysis found that the acquired signature could differentiate the outcome of low- and high-risk cases. Moreover, the signature could also serve as an independent prognostic factor for IDH-mutant GBM in the multivariate Cox regression analysis. Gene ontology and gene set enrichment analyses revealed that gene sets correlated with high-risk group were involved in cell cycle, cell proliferation, DNA replication and repair. These finding highlights heterogeneity within IDH-mutant GBMs and will advance our molecular understanding of this lethal cancer.

Kinesin family member 11 is a potential therapeutic target and is suppressed by microRNA-30a in breast cancer

Kinesin family member 11 (KIF11) is a plus end‐directed kinesin indispensable for the formation of the bipolar spindle in metaphase, where it objects to the action of minus end‐directed molecular motors. Here, we hypothesize that KIF11 might be a therapeutic target of breast cancer and regulated by miR‐30a. Cell Counting Kit 8 assays were used to investigate cell proliferation. Invasion assays were used to survey the motility of cells. Kaplan‐Meier and Cox proportional analyses were employed for this outcome study. The prognostic significance and performance of KIF11 were validated on 17 worldwide independent microarray datasets and two The Cancer Genome Atlas‐Breast Invasive Carcinoma sets. microRNA was predicted targeting KIF11 through sequence alignment in microRNA.org and confirmed by coexpression analysis in human breast cancer samples. Dual‐luciferase reporter assays were employed to validate the interaction between miR‐30a and KIF11 further. Higher KIF11 mRNA levels and lower miR‐30a were significantly associated with poor survival of breast cancer patients. Inhibition of KIF11 by small‐hairpin RNA significantly reduced the proliferation and invasion capabilities of the breast cancer cells. Meanwhile, downregulation of KIF11 could enhance the cytotoxicity of adriamycin in breast cancer cell lines MCF‐7 and MDA‐MB‐231. A population study also validated that chemotherapy and radiotherapy significantly improved survival in early‐stage breast cancer patients with low KIF11 expression levels. Further bioinformatics analysis demonstrated that miR‐30a could interact with KIF11 and validated by dual‐luciferase reporter assays. Therefore, KIF11 is a potential therapeutic target of breast cancer. miR‐30a could specifically interact with KIF11 and suppress its expression in breast cancer.

Genetic Variations in miR-30 Family Member Regulatory Regions Are Associated with Breast Cancer Risk in a Chinese Population

MicroRNAs (miRNAs) of the miR-30 family are closely linked with tumor metastasis and play key roles in the complex malignant phenotypes of cancers by targeting many tumor-related genes. Deregulated expression of miR-30 family members has been commonly observed in breast cancer. However, associations between the genetic variants in the regulatory region of miR-30 family and the risk of breast cancer are still limited, especially in the Chinese Han population. In the present study, we conducted a case-control analysis wherein 1064 breast cancer patients and 1073 healthy controls underwent genotyping of 10 SNPs in the regulatory region of miR-30 family members. Multivariate logistic regression analyses illustrated that the rs763354 variant in the miR-30a regulatory region was linked with a significant decrease in breast cancer risk in an additive model (adjusted OR = 0.86, 95% CI: 0.75-0.98, P = 0.022). Further, eQTL analyses also indicated that this SNP was associated with miR-30a expression levels in breast cancer samples compiled in the TCGA database (P = 0.020). The Kaplan-Meier plotter showed that breast cancer patients with higher miR-30a expression have significantly better outcomes than do patients expressing low levels of this miRNA (HR = 0.75, 95% CI: 0.61-0.91, P = 0.0041). Together, these findings suggest that the miR-30a rs763354 SNP is an important regulator of breast cancer risk, thus making it a potentially viable prognostic biomarker and one that can be used to guide therapeutic treatment in affected patients.

Heterochromatin protein 1 (HP1): interactions with itself and chromatin components

Isoforms of heterochromatin protein 1 (HP1) have been known to perform a multitude of functions ranging from gene silencing, gene activation to cell cycle regulation, and cell differentiation. This functional diversity arises from the dissimilarities coded in protein sequence which confers different biophysical and biochemical properties to individual structural elements of HP1 and thereby different behavior and interaction patterns. Hence, an understanding of various interactions of the structural elements of HP1 will be of utmost importance to better elucidate chromatin dynamics in its presence. In this review, we have gathered available information about interactions of HP1 both within and with itself as well as with chromatin elements. Also, the possible implications of these interactions are discussed.

Discovery, expression, cellular localization, and molecular properties of a novel, alternative spliced HP1γ isoform, lacking the chromoshadow domain

By reading the H3K9Me3 mark through their N-terminal chromodomain (CD), HP1 proteins play a significant role in cancer-associated processes, including cell proliferation, differentiation, chromosomal stability, and DNA repair. Here, we used a combination of bioinformatics-based methodologies, as well as experimentally-derived datasets, that reveal the existence of a novel short HP1γ (CBX3) isoform, named here sHP1γ, generated by alternative splicing of the CBX3 locus. The sHP1γ mRNA encodes a protein composed of 101 residues and lacks the C-terminal chromoshadow domain (CSD) that is required for dimerization and heterodimerization in the previously described 183 a. a HP1γ protein. Fold recognition, order-to-disorder calculations, threading, homology-based molecular modeling, docking, and molecular dynamic simulations show that the sHP1γ is comprised of a CD flanked by intrinsically disordered regions (IDRs) with an IDR-CD-IDR domain organization and likely retains the ability to bind to the H3K9Me3. Both qPCR analyses and mRNA-seq data derived from large-scale studies confirmed that sHP1γ mRNA is expressed in the majority of human tissues at approximately constant ratios with the chromoshadow domain containing isoform. However, sHP1γ mRNA levels appear to be dysregulated in different cancer types. Thus, our data supports the notion that, due to the existence of functionally different isoforms, the regulation of HP1γ-mediated functions is more complex than previously anticipated.

Circular RNA circHIAT1 inhibits proliferation and epithelial-mesenchymal transition of gastric cancer cell lines through downregulation of miR-21

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Circular RNA circHIAT1 has been proved to play an antitumor role. We aimed to explore the function and mechanism of circHIAT1 in GC. MKN28 and MKN45 cells were transfected with PLCDH-circHIAT1, miR-21 mimic, and relative control. Cell viability and apoptosis were examined through Cell Counting Kit-8 and flow cytometry, respectively. CircHIAT1 expression and other relative factors were tested through quantitative reverse transcription-polymerase chain reaction and Western blot analysis, respectively. Our findings demonstrated that circHIAT1 was lowly expressed in GC tissues. After transfection with PLCDH-circHIAT1 in MKN28 and MKN45 cells, cell viability was decreased, while the expression levels of p53 and p21 were raised, as well as apoptosis. Besides this, the epithelial-mesenchymal transition process was inhibited by PLCDH-circHIAT1 transfection. Mechanistically, miR-21 expression was upregulated in GC tissues and could be negatively regulated by circHIAT1. Further experiments showed that the addition of miR-21 mimic reversed the growth inhibition effects of circHIAT1 overexpression. Moreover, circHIAT1 inhibited the activation of phosphatase and tensin homolog/phosphatidylinositol 3 kinase/protein kinase B and extracellular signal-regulated kinase signal pathways via downregulating miR-21. CircHIAT1 functioned as a tumor inhibitor in GC cells through downregulating miR-21, and could be a novel target for GC treatment.

B7-H3 promotes the cell cycle-mediated chemoresistance of colorectal cancer cells by regulating CDC25A

Colorectal cancer (CRC) is one of the most common malignancies, and chemoresistance is one of the key obstacles in the clinical outcome. Here, we studied the function of B7-H3 in regulating cell cycle-mediated chemoresistance in CRC. The ability of B7-H3 in regulating chemoresistance was investigated via cell viability, clonogenicity, apoptosis and cycle analysis in vitro. Moreover, the role of B7-H3/CDC25A axis in regulating chemoresistance in vivo in the xenograft tumor models by intraperitoneal injection of oxaliplatin (L-OHP) and CDC25A inhibitors. The correlation between B7-H3 and CDC25A was examined in the CRC patients by immunohistochemistry (IHC) and pathological analyses. We found that B7-H3 could effectively enhance the resistance to a chemotherapeutic drug (oxaliplatin or 5-fluorouracil) via CDC25A. B7-H3 regulated the expression of CDC25A by the STAT3 signaling pathway in CRC cells. Furthermore, overexpression of B7-H3 enhanced chemoresistance by reducing the G2/M phase arrest in a CDC25A-dependent manner. Silencing CDC25A or treatment with CDC25A inhibitor could reverse the B7-H3-induced chemoresistance of cancer cells. Moreover, both B7-H3 and CDC25A were significantly upregulated in CRC samples compared with normal adjacent tissues and that the levels correlated with tumor stage. CDC25A was positively correlated with B7-H3 expression in this cohort. Taken together, our findings provide an alternative mechanism by which CRC cells can acquire chemoresistance via the B7-H3/CDC25A axis.

Transcriptional expressions of Chromobox 1/2/3/6/8 as independent indicators for survivals in hepatocellular carcinoma patients

Chromobox (CBX) proteins are important components of epigenetic regulation complexes known to play key roles in hepatocellular carcinoma (HCC). Little is known about the function of distinct CBXs in HCC. To address this issue, the study investigated the roles of CBXs in the prognosis of HCC using ONCOMINE, UALCAN, Human Protein Atlas, Kaplan-Meier Plotter, c-BioPortal databases. Over expressions of 8 CBXs members were found to be significantly associated with clinical cancer stages and pathological tumor grades in HCC patients. Besides, higher mRNA expressions of CBX1/2/3/6/8 were found to be significantly associated with shorter overall survival (OS) in HCC patients, while higher mRNA expression of CBX7 was associated with favorable OS. Multivariate analysis also showed that high mRNA expressions of CBX1/2/3/6/8 were independent prognostic factors for shorter OS of HCC patients. Moreover, high mutation rate of CBXs (51%) was also observed in HCC patients, and genetic alteration in CBXs was associated with shorter OS and disease-free survival (DFS) in HCC patients. Taken together, these results indicated that CBX1/2/3/6/8 could be prognostic biomarkers for survivals of HCC patients.

The Intricate Interplay between Epigenetic Events, Alternative Splicing and Noncoding RNA Deregulation in Colorectal Cancer

Colorectal cancer (CRC) results from a transformation of colonic epithelial cells into adenocarcinoma cells due to genetic and epigenetic instabilities, alongside remodelling of the surrounding stromal tumour microenvironment. Epithelial-specific epigenetic variations escorting this process include chromatin remodelling, histone modifications and aberrant DNA methylation, which influence gene expression, alternative splicing and function of non-coding RNA. In this review, we first highlight epigenetic modulators, modifiers and mediators in CRC, then we elaborate on causes and consequences of epigenetic alterations in CRC pathogenesis alongside an appraisal of the complex feedback mechanisms realized through alternative splicing and non-coding RNA regulation. An emphasis in our review is put on how this intricate network of epigenetic and post-transcriptional gene regulation evolves during the initiation, progression and metastasis formation in CRC.