CBX3 promotes proliferation and regulates glycolysis via suppressing FBP1 in pancreatic cancer

Deletion of ENO1 sensitizes pancreatic cancer cells to gemcitabine via MYC/RRM1-mediated glycolysis

Glycolysis is a critical metabolic pathway in cancer cells, fulfilling their energy requirements, supporting biosynthesis, maintaining redox balance, and enabling survival in hostile environments. Alpha-enolase (ENO1) has been identified as a key promoter of tumor progression through its involvement in glycolysis. This study aims to elucidate the relationship between ENO1, glycolysis, and gemcitabine sensitivity in pancreatic cancer (PC). The expression levels of ENO1 in PC were analyzed using the GEPIA2 database, Kaplan-Meier survival plots, and immunohistochemistry (IHC). To assess the impact of ENO1 on gemcitabine sensitivity, we manipulated ENO1 expression in PC cell lines through overexpression and silencing techniques. Subsequent analyses included flow cytometry assays, glucose uptake and lactate production measurements, and cytotoxicity assays. The underlying mechanisms by which ENO1 modulates gemcitabine sensitivity were explored using Western blotting (WB). ENO1 was found to be significantly overexpressed in PC tissues, and elevated ENO1 levels were associated with poorer prognosis in PC patients. Overexpression of ENO1 reduced the sensitivity of PC cells to gemcitabine, enhancing cell proliferation, migration, and invasion by altering the cell cycle and inhibiting apoptosis. Conversely, silencing ENO1 decreased glycolysis in PC cells and heightened their sensitivity to gemcitabine. Furthermore, glycolysis inhibition-achieved through ENO1 knockdown, glucose deprivation, or treatment with 2-Deoxy-D-glucose (2-DG)-further enhanced the susceptibility of PC cells to gemcitabine. Mechanistically, ENO1 was found to regulate the expression of gemcitabine resistance-related genes, particularly ribonucleotide reductase catalytic subunit M1 (RRM1), via MYC through the glycolytic pathway, thereby contributing to gemcitabine resistance. This study demonstrates that ENO1 plays a crucial role in PC progression and is closely linked to gemcitabine resistance through its regulation of the glycolytic pathway.

The role of fructose-1,6-bisphosphatase 1 on regulating the cancer progression and drug resistance

Fructose-1,6-bisphosphatase 1 (FBP1) is the enzyme that limits the process of gluconeogenesis as it facilitates the hydrolysis of fructose-1,6-bisphosphate(F-1,6-BP) to produce fructose-6-phosphate(F6P) and inorganic phosphate. Gluconeogenesis is the production of glucose from small carbohydrate substrates. The gluconeogenic process is typically suppressed in cancer because it inhibits glycolysis. Apart from its involvement in cellular glucose metabolism, FBP1 also plays a role in gene transcription, mRNA translation and stability regulation, and the immune microenvironment of tumors. Because of its multifaceted functions, the mechanisms by which FBP1 is involved in tumor development are complex. Moreover, FBP1 deficiency is associated with radiation and chemotherapy resistance and poor prognosis in cancer patients. Restoration of FBP1 expression in cancer cells is expected to hold promise for cancer therapy. However, up to now few reviews have systematically summarized the important functional mechanisms of FBP1 in tumorigenesis and the small molecule compounds that restore FBP1 expression. Therefore, this article addresses the question "How does FBP1 contribute to cancer progression, and can targeting FBP1 be a potential therapeutic approach?" by summarizing the effects of FBP1 on cancer development and progression as well as its mediated drug resistance and the future clinical applications of potential small molecule modulators targeting FBP1.

Fructose-1,6-bisphosphatase 1 in cancer: Dual roles, mechanistic insights, and therapeutic potential - A comprehensive review

Fructose-1,6-bisphosphatase 1 (FBP1) is a key gluconeogenic enzyme that plays complex and context-dependent roles in cancer biology. This review comprehensively examines FBP1's dual functions as both a tumor suppressor and an oncogene across various cancer types. In many cancers, such as hepatocellular carcinoma, clear cell renal cell carcinoma, and lung cancer, downregulation of FBP1 contributes to tumor progression through metabolic reprogramming, promoting glycolysis, and altering the tumor microenvironment. Conversely, in certain contexts like breast and prostate cancers, FBP1 overexpression is associated with tumor promotion, indicating its oncogenic potential. The review explores FBP1's interactions with immune cells within the tumor microenvironment, influencing immune surveillance and tumor immune escape mechanisms. Additionally, FBP1 emerges as a promising diagnostic and prognostic biomarker, with expression levels correlating with patient outcomes in multiple cancers. Future therapeutic strategies targeting FBP1 are discussed, including inhibitors, activators, epigenetic modulation, and combination therapies, while addressing the challenges posed by its dual nature. Understanding the multifaceted roles of FBP1 offers valuable insights into cancer metabolism and opens avenues for personalized therapeutic interventions.

CBX3 contributes to pancreatic adenocarcinoma progression via promoting KIF20A expression

Pancreatic adenocarcinoma (PAAD) is one of the malignant tumors with poor prognosis. This study aims to inquiry the effects of Chromobox homologue 3 (CBX3) on PAAD progression. Pan-cancer analysis of CBX3 and its correlation with PAAD progression were investigated by informatics analysis. The role of CBX3 in PAAD was explored in vitro and in vivo. Cell viability, proliferation, migration and invasion were inspected by CCK-8 assay, EdU staining, scratch test and transwell assay, respectively. The morphology of tumors was observed by hematoxylin-eosin staining. Immunohistochemistry (Ki67) was performed to inspect the proliferation of tumor tissue. The protein levels were measured by western blot. Moreover, the downstream genes of CBX3 were screened, and the effects of target gene on PAAD was investigated in vitro. CBX3 was overexpressed in multi cancers, and high CBX3 expression indicated poor prognosis in PAAD. Through the in vitro assays, knockdown of CBX3 suppressed the viability, migration and invasion of PAAD cells, and restrained tumor growth in vivo. Subsequently, kinesin family member 20A (KIF20A) was screened as the downstream gene of CBX3, which was up-regulated in PAAD and related to low overall survival. Mechanistically, we discovered that CBX3 could regulate KIF20A expression. Knockdown of CBX3 promoted the oncogenic effects of KIF20A silencing on PAAD cells, and attenuated the pro-oncogenic effects of KIF20A overexpression on PPAD. Collectively, silencing CBX3 suppressed PAAD progression through regulating KIF20A expression, providing an underlying target for PAAD treatment.

Impact of miRNAs involved in the STAT3 signaling pathway on esophageal cancer (Review)

Esophageal cancer (ESCA) is a common tumor noted in the digestive tract, which is highly malignant due to unclear early symptoms and poor last‑stage treatment effects; its mortality rate is relatively high. MicroRNA (miR) and signal transducer and activator of transcription 3 (STAT3) are key components of cellular signaling pathways; their interaction forms a complex and intricate information network that controls several types of biological behaviors in the cells. In the tumor cell, these signal transduction pathways are abnormally active, indicating that the STAT3 signaling pathway mediated by miRs is involved in the progression of various cancer types. The present review introduces the biological characteristics of miR and STAT3 and their relationship with ESCA. It summarizes the regulation of ESCA by the miR and STAT3 signaling pathways and analyzes the effects of these pathways on proliferation, apoptosis, invasion, metastasis and immune escape of cancer cells, as well as the impact on patient survival and prognosis. The purpose of the present review is to assess the miR/STAT3 signaling pathway in ESCA, improve the understanding of the pathogenesis of ESCA and facilitate the identification of therapeutic targets for ESCA.

Integrating Bulk RNA and Single-Cell RNA Sequencing Identifies and Validates Lactylation-Related Signatures for Intervertebral Disc Degeneration

Glycolysis-related lactylation has gained wide attention for regulating various cellular functions and diseases. Nevertheless, its intricate involvement in intervertebral disc degeneration (IVDD) is not yet fully understood. In this study, we unrevealed the intricate association between elevated lactylation levels and the development of IVDD. Subsequently, we harvested the lactylation-related genes (LRGs) and systematically analysed the expression levels of these genes to establish a gene signature related to IVDD through multiple bulk RNA sequencing data. Six hub LRGs were determined and closely associated with the increased severity of IVDD. Among the six genes, CBX3 was the most upregulated in both in vivo and in vitro experiments. Furthermore, molecular docking identified atosiban acetate as a specific inhibitor for CBX3, and inhibiting the expression of CBX3 using atosiban acetate significantly repressed the glycolysis activity and global lactylation level, thus alleviating the progression of IVDD. In conclusion, the lactylation correlates positively with IVDD and the LRG signature could be used as a biomarker for the effective clinical treatment of IVDD. CBX3 emerged as one of the key LRGs in IVDD, and atosiban acetate, as a specific inhibitor for CBX3, may be a promising therapeutic candidate for IVDD by affecting lactylation.

HOXC4 promotes proliferation of pancreatic cancer cells by increasing LDHA-mediated glycolysis

Homeobox C4 (HOXC4) is a member of homeobox family and acts as a transcription factor in regulating morphological development. The current study aimed to determine its role in pancreatic cancer (PC). Bioinformatics analysis was employed to assess the expression and clinical significance of HOXC4 in PC, while the expression of HOXC4 was further confirmed in PC tissues through quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The impact of HOXC4 on PC cell proliferation was evaluated using various assays including Cell Counting Kit-8, colony formation, apoptosis detection, cell cycle analysis, and subcutaneous tumorigenesis. Extracellular acidification rate, glucose uptake, and lactate production measurements were detected to examine the impact of HOXC4 on glycolysis. The relationship between HOXC4 and lactate dehydrogenase A (LDHA) was investigated using CHIP assay, luciferase reporter assay, and western blot. Notably, there was a substantial increase in HOXC4 expression in PC, and patients with elevated HOXC4 levels exhibited shorter survival durations. HOXC4 knockdown resulted in significantly reduced proliferation and colony formation in PC cells, accompanied by increased apoptosis and G1 phase arrest. The overexpression of HOXC4 resulted in contrasting effects. In vivo, the proliferation of PC cells was diminished upon the knockdown of HOXC4. HOXC4 exhibited an increase in LDHA expression by binding to its promoter. The suppressive effects of HOXC4 knockdown on PC cells were counteracted upon the restoration of LDHA. In conclusion, HOXC4 promoted the proliferation of PC cells by increasing LDHA-mediated glycolysis. HOXC4 can act as a target for PC therapy.

New insights into the regulation of bile acids synthesis during the early stages of liver regeneration: A human and experimental study

BACKGROUND AND AIMS

Liver regeneration is essential for the preservation of homeostasis and survival. Bile acids (BAs)-mediated signaling is necessary for liver regeneration, but BAs levels need to be carefully controlled to avoid hepatotoxicity. We studied the early response of the BAs-fibroblast growth factor 19 (FGF19) axis in healthy individuals undergoing hepatectomy for living donor liver transplant. We also evaluated BAs synthesis in mice upon partial hepatectomy (PH) and acute inflammation, focusing on the regulation of cytochrome-7A1 (CYP7A1), a key enzyme in BAs synthesis from cholesterol.

METHODS

Serum was obtained from twelve human liver donors. Mice underwent 2/3-PH or sham-operation. Acute inflammation was induced with bacterial lipopolysaccharide (LPS) in mice fed control or antoxidant-supplemented diets. BAs and 7α-hydroxy-4-cholesten-3-one (C4) levels were measured by HPLC-MS/MS; serum FGF19 by ELISA. Gene expression and protein levels were analyzed by RT-qPCR and western-blot.

RESULTS

Serum BAs levels increased after PH. In patients with more pronounced hypercholanemia, FGF19 concentrations transiently rose, while C4 levels (a readout of CYP7A1 activity) dropped 2 h post-resection in all cases. Serum BAs and C4 followed the same pattern in mice 1 h after PH, but C4 levels also dropped in sham-operated and LPS-treated animals, without marked changes in CYP7A1 protein levels. LPS-induced serum C4 decline was attenuated in mice fed an antioxidant-supplemented diet.

CONCLUSIONS

In human liver regeneration FGF19 upregulation may constitute a protective response from BAs excess during liver regeneration. Our findings suggest the existence of post-translational mechanisms regulating CYP7A1 activity, and therefore BAs synthesis, independent from CYP7A1/Cyp7a1 gene transcription.

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.

CBX7 is involved in the progression of cervical cancer through the ITGβ3/TGFβ1/AKT pathway

The chromobox protein homolog 7 (CBX7) serves a tumor-suppressive role in human malignant neoplasias. The downregulation of CBX7 is associated with the poor prognosis and aggressiveness of various human cancers. However, the biological functions and underlying mechanisms of CBX7 in cervical cancer remain unclear. The present study investigated the role and mechanism of CBX7 in cervical cancer. Lentivirus and siRNA were used to construct cervical cancer cells with stable CBX7 knockdown and SiHa xenograft models. The cell growth, migration, invasion and apoptosis were observed through in vivo and in vitro experiments. The expression levels of CBX7, integrin β3 (ITGβ3), transforming growth factor β1 (TGFβ1), phosphatidylinositol-3-kinase (PI3K), AKT, E-cadherin (E-cad) and vimentin (VIM) were detected by western blot analysis and reverse transcription-quantitative PCR. The correlation between CBX7 and these genes was analyzed. TGFβ1 was also silenced through shRNA in cells with stable CBX7 knockdown to detect its effect on cell growth, invasion and apoptosis, and on pathway-related gene expression. It was revealed that knockdown of CBX7 promoted the proliferation, migration, and invasion of cervical cancer cells, and inhibited apoptosis. In addition, CBX7 knockdown promoted tumor growth in vivo. Correlation analysis demonstrated that CBX7 was negatively correlated with ITGβ3, TGFβ1, PI3K, AKT, phosphorylated AKT and VIM, but positively correlated with E-cad. Moreover, the knockdown of TGFβ1 reversed the promotion of cell proliferation and inhibition of apoptosis induced by CBX7 knockdown and attenuated the increase of ITGβ3, TGFβ1, PI3K, AKT and VIM caused by CBX7 knockdown. In conclusion, the findings of the present study indicated that the downregulation of CBX7 enhances cell migration and invasion while inhibiting cell apoptosis in cervical cancer by modulating the ITGβ3/TGFβ1/AKT signaling pathways.

LncRNA TYMSOS facilitates breast cancer metastasis and immune escape through downregulating ULBP3

The focus of the study is to examine the function of TYMSOS in immune escape of breast cancer, which is the most frequently diagnosed malignancy among women globally. Our study demonstrated that upregulated TYMSOS was associated with unfavorable prognosis and immune escape in breast cancer. TYMSOS promoted the malignant phenotypes of breast cancer cells, and reduced the cytotoxicity of NK92 cells on these cells. CBX3 was a downstream effector in TYMSOS-induced malignant phenotypes in breast cancer cells. Mechanistic studies showed that TYMSOS facilitated CBX3-mediated transcriptional repression of ULBP3, and it also promoted SYVN1-mediated ubiquitin-proteasomal degradation of ULBP3. TYMSOS promoted cell growth, metastasis, and immune escape via CBX3/ULBP3 or SYVN1/ULBP3 axis. The in vivo studies further showed that silencing of TYMSOS repressed tumor growth and boosted NK cell cytotoxicity. In sum, TYMSOS boosted breast cancer metastasis and immune escape via CBX3/ULBP3 or SYVN1/ULBP3 axis.

Integrated transcriptomics, proteomics and metabolomics-based analysis uncover TAM2-associated glycolysis and pyruvate metabolic remodeling in pancreatic cancer

Introduction

Tumor-associated macrophage 2 (TAM2) abundantly infiltrates pancreatic ductal adenocarcinoma (PAAD), and its interaction with malignant cells is involved in the regulation of tumor metabolism. In this study, we explored the metabolic heterogeneity involved in TAM2 by constructing TAM2-associated metabolic subtypes in PAAD.

Materials and methods

PAAD samples were classified into molecular subtypes with different metabolic characteristics based on a multi-omics analysis strategy. 20 PAAD tissues and 10 normal pancreatic tissues were collected for proteomic and metabolomic analyses. RNA sequencing data from the TCGA-PAAD cohort were used for transcriptomic analyses. Immunohistochemistry was used to assess TAM2 infiltration in PAAD tissues.

Results

The results of transcriptomics and immunohistochemistry showed that TAM2 infiltration levels were upregulated in PAAD and were associated with poor patient prognosis. The results of proteomics and metabolomics indicated that multiple metabolic processes were aberrantly regulated in PAAD and that this dysregulation was linked to the level of TAM2 infiltration. WGCNA confirmed pyruvate and glycolysis/gluconeogenesis as co-expressed metabolic pathways of TAM2 in PAAD. Based on transcriptomic data, we classified the PAAD samples into four TAM2-associated metabolic subtypes (quiescent, pyruvate, glycolysis/gluconeogenesis and mixed). Metabolic subtypes were each characterized in terms of clinical prognosis, tumor microenvironment, immune cell infiltration, chemotherapeutic drug sensitivity, and functional mechanisms.

Conclusion

Our study confirmed that the metabolic remodeling of pyruvate and glycolysis/gluconeogenesis in PAAD was closely related to TAM2. Molecular subtypes based on TAM2-associated metabolic pathways provided new insights into prognosis prediction and therapy for PAAD patients.

PSMC4 promotes prostate carcinoma progression by regulating the CBX3-EGFR-PI3K-AKT-mTOR pathway

Proteasome 26S subunit ATPase 4 (PSMC4) could regulate cancer progression. However, the function of PSMC4 in prostate carcinoma (PCa) progression requires further clarification. In the study, PSMC4 and chromobox 3 (CBX3) levels were verified by TCGA data and tissue microarrays. Cell counting kit-8, cell apoptosis, cell cycle, wound healing, transwell and xenograft tumour model assays were performed to verify biological functions of PSMC4 in PCa. RNA-seq, PCR, western blotting and co-IP assays were performed to verify the mechanism of PSMC4. Results showed that PSMC4 level was significantly increased in PCa tissues, and patients with PCa with a high PSMC4 level exhibited shorter overall survival. PSMC4 knockdown markedly inhibited cell proliferation, cell cycle and migration in vitro and in vivo, and significantly promoted cell apoptosis. Then further study revealed that CBX3 was a downstream target of PSMC4. PSMC4 knockdown markedly reduced CBX3 level, and inhibited PI3K-AKT-mTOR signalling. CBX3 overexpression markedly promoted epidermal growth factor receptor (EGFR) level. Finally, PSMC4 overexpression showed reverse effect in DU145 cells, and the effects of PSMC4 overexpression on cell proliferation, migration and clonal formation were rescued by the CBX3 knockdown, and regulated EGFR-PI3K-AKT-mTOR signalling. In conclusion, PSMC4 could regulate the PCa progression by mediating the CBX3-EGFR-PI3K-AKT-mTOR pathway. These findings provided a new target for PCa treatment.

Metabolic Rewiring and Stemness: A Critical Attribute of Pancreatic Cancer Progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases with a poor 5-year survival rate. PDAC cells rely on various metabolic pathways to fuel their unlimited proliferation and metastasis. Reprogramming glucose, fatty acid, amino acid, and nucleic acid metabolisms contributes to PDAC cell growth. Cancer stem cells are the primary cell types that play a critical role in the progression and aggressiveness of PDAC. Emerging studies indicate that the cancer stem cells in PDAC tumors are heterogeneous and show specific metabolic dependencies. In addition, understanding specific metabolic signatures and factors that regulate these metabolic alterations in the cancer stem cells of PDAC paves the way for developing novel therapeutic strategies targeting CSCs. In this review, we discuss the current understanding of PDAC metabolism by specifically exploring the metabolic dependencies of cancer stem cells. We also review the current knowledge of targeting these metabolic factors that regulate CSC maintenance and PDAC progression.

NCAPG is transcriptionally regulated by CBX3 and activates the Wnt/β-catenin signaling pathway to promote proliferation and the cell cycle and inhibit apoptosis in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is highly heterogeneous at the genetic and molecular level and a major contributor to cancer-death worldwide. Non-structural maintenance of chromosomes (SMC) condensin I complex subunit G (NCAPG) is a subunit of condensin I and has been shown to be associated with the prognosis of cancers. This study investigated the functional role of NCAPG in CRC and its mechanism.

METHODS

Messenger RNA (mRNA) and protein expressions of NCAPG and chromobox protein homolog 3 (CBX3) were determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. The proliferation, cycle, and apoptosis of HCT116 cells were analyzed by Cell Counting Kit-8 (CCK-8), flow cytometry, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. RT-qPCR and western blot were used to determine the transfection efficacy of short hairpin (sh)-NCAPG and sh-CBX3. Western blot was used to explore cycle-, apoptosis-, and Wnt/β-catenin signaling-related proteins, and the activity of NCAPG promoter was evaluated using a luciferase report assay. The expressions of cleaved caspase9 and cleaved caspase3 were assessed by colorimetric caspase activity assay.

RESULTS

The results showed that NCAPG expression was elevated in CRC cells. After transfection with sh-NCAPG, NCAPG expression was reduced. It was also discovered that NCAPG knockdown suppressed proliferation and the cell cycle but induced apoptosis in HCT116 cells. The Human Transcription Factor Database (HumanTFDB; http://bioinfo.life.hust.edu.cn/HumanTFDB#!/) predicted the binding sites of CBX3 and NCAPG promoters. Meanwhile, the Encyclopedia of RNA Interactomes (ENCORI) database (https://starbase.sysu.edu.cn/) revealed that CBX3 was positively correlated with NCAPG. Our results showed that NCAPG was transcriptionally regulated by CBX3. Additionally, Wnt/β-catenin signaling was discovered to be activated by CBX3 overexpression. Further experiments showed that NCAPG transcriptionally regulated by CBX3 activated Wnt/β-catenin signaling to regulate the proliferation, cell cycle, and apoptosis of HCT116 cells.

CONCLUSIONS

Collectively, the results of our study indicated that NCAPG was transcriptionally regulated by CBX3 and activated the Wnt/β-catenin signaling pathway to facilitate the progression of CRC.

Chromobox Family Proteins as Putative Biomarkers for Breast Cancer Management: A Preliminary Study Based on Bioinformatics Analysis and qRT-PCR Validation

Background

Epigenetic modification of chromatin is an important step in the regulation of gene expression. The chromobox family proteins (CBXs), as epigenetic modifier, may play a vital role in tumorigenesis and cancer progression. Herein we explored the correlation between CBXs and breast cancer (BC) via the bioinformatics approach and qRT-PCR validation.

Methods

Several databases, including GEPIA, TCGA, GEO, K-M plotter, STRING, DAVID, cBioPortal, CIBERSORT, and HPA were employed to analyze the expression levels of CBXs and the correlations between CBXs and prognosis (overall and recurrence-free survival) in BC. We analyzed molecular functions, genetic variations, transcription factors of CBXs, and immune cell infiltration status. ROC curve analysis was performed to determine the predictive value of CBXs. RNA extracted from 11 human BC and paired adjacent normal tissues were subjected to qRT-PCR.

Results

The mRNA expression level of CBX1-5 was significantly upregulated, while that of CBX7 was significantly downregulated in BC; no expression disparities were observed in CBX6/8 expression. Further, high mRNA expression of CBX1/2/3/4/8 correlated with advanced BC, whereas high mRNA expression of CBX6/7 correlated with early BC. High mRNA expressions of CBX1/2/3/5 predict poor OS and RFS, while higher mRNA expressions of CBX6/7 predict better OS and RFS in patients with BC. ROC curve analysis revealed that CBX3 showed excellent discriminatory ability. Gene ontology enrichment analysis showed that CBXs primarily participated in SUMOylation and post-/transcriptional regulation. Moreover, they presented varying degrees of amplification in BC tissues and were related to the infiltration of various immune cells.

Conclusion

CBXs can serve as putative biomarkers for BC. Further studies are warranted to determine the exact molecular mechanisms underlying the action of CBXs in BC, particularly CBX1/2/3/5/7.

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.

New molecular mechanisms in cholangiocarcinoma: signals triggering interleukin-6 production in tumor cells and KRAS co-opted epigenetic mediators driving metabolic reprogramming

BACKGROUND

Cholangiocarcinoma (CCA) is still a deadly tumour. Histological and molecular aspects of thioacetamide (TAA)-induced intrahepatic CCA (iCCA) in rats mimic those of human iCCA. Carcinogenic changes and therapeutic vulnerabilities in CCA may be captured by molecular investigations in bile, where we performed bile proteomic and metabolomic analyses that help discovery yet unknown pathways relevant to human iCCA.

METHODS

Cholangiocarcinogenesis was induced in rats (TAA) and mice (JnkΔhepa + CCl4 + DEN model). We performed proteomic and metabolomic analyses in bile from control and CCA-bearing rats. Differential expression was validated in rat and human CCAs. Mechanisms were addressed in human CCA cells, including Huh28-KRASG12D cells. Cell signaling, growth, gene regulation and [U-13C]-D-glucose-serine fluxomics analyses were performed. In vivo studies were performed in the clinically-relevant iCCA mouse model.

RESULTS

Pathways related to inflammation, oxidative stress and glucose metabolism were identified by proteomic analysis. Oxidative stress and high amounts of the oncogenesis-supporting amino acids serine and glycine were discovered by metabolomic studies. Most relevant hits were confirmed in rat and human CCAs (TCGA). Activation of interleukin-6 (IL6) and epidermal growth factor receptor (EGFR) pathways, and key genes in cancer-related glucose metabolic reprogramming, were validated in TAA-CCAs. In TAA-CCAs, G9a, an epigenetic pro-tumorigenic writer, was also increased. We show that EGFR signaling and mutant KRASG12D can both activate IL6 production in CCA cells. Furthermore, phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in serine-glycine pathway, was upregulated in human iCCA correlating with G9a expression. In a G9a activity-dependent manner, KRASG12D promoted PHGDH expression, glucose flow towards serine synthesis, and increased CCA cell viability. KRASG12D CAA cells were more sensitive to PHGDH and G9a inhibition than controls. In mouse iCCA, G9a pharmacological targeting reduced PHGDH expression.

CONCLUSIONS

In CCA, we identified new pro-tumorigenic mechanisms: Activation of EGFR signaling or KRAS mutation drives IL6 expression in tumour cells; Glucose metabolism reprogramming in iCCA includes activation of the serine-glycine pathway; Mutant KRAS drives PHGDH expression in a G9a-dependent manner; PHGDH and G9a emerge as therapeutic targets in iCCA.

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.

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.

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.

The role of fructose 1,6-bisphosphate-mediated glycolysis/gluconeogenesis genes in cancer prognosis

Metabolic reprogramming and elevated glycolysis levels are associated with tumor progression. However, despite cancer cells selectively inhibiting or expressing certain metabolic enzymes, it is unclear whether differences in gene profiles influence patient outcomes. Therefore, identifying the differences in enzyme action may facilitate discovery of gene ontology variations to characterize tumors. Fructose-1,6-bisphosphate (F-1,6-BP) is an important intermediate in glucose metabolism, particularly in cancer. Gluconeogenesis and glycolysis require fructose-1,6-bisphosphonates 1 (FBP1) and fructose-bisphosphate aldolase A (ALDOA), which participate in F-1,6-BP conversion. Increased expression of ALDOA and decreased expression of FBP1 are associated with the progression of various forms of cancer in humans. However, the exact molecular mechanism by which ALDOA and FBP1 are involved in the switching of F-1,6-BP is not yet known. As a result of their pancancer pattern, the relationship between ALDOA and FBP1 in patient prognosis is reversed, particularly in lung adenocarcinoma (LUAD) and liver hepatocellular carcinoma (LIHC). Using The Cancer Genome Atlas (TCGA), we observed that FBP1 expression was low in patients with LUAD and LIHC tumors, which was distinct from ALDOA. A similar trend was observed in the analysis of Cancer Cell Line Encyclopedia (CCLE) datasets. By dissecting downstream networks and possible upstream regulators, using ALDOA and FBP1 as the core, we identified common signatures and interaction events regulated by ALDOA and FBP1. Notably, the identified effectors dominated by ALDOA or FBP1 were distributed in opposite patterns and can be considered independent prognostic indicators for patients with LUAD and LIHC. Therefore, uncovering the effectors between ALDOA and FBP1 will lead to novel therapeutic strategies for cancer patients.

Mechanisms of Polycomb group protein function in cancer

Cancer arises from a multitude of disorders resulting in loss of differentiation and a stem cell-like phenotype characterized by uncontrolled growth. Polycomb Group (PcG) proteins are members of multiprotein complexes that are highly conserved throughout evolution. Historically, they have been described as essential for maintaining epigenetic cellular memory by locking homeotic genes in a transcriptionally repressed state. What was initially thought to be a function restricted to a few target genes, subsequently turned out to be of much broader relevance, since the main role of PcG complexes is to ensure a dynamically choregraphed spatio-temporal regulation of their numerous target genes during development. Their ability to modify chromatin landscapes and refine the expression of master genes controlling major switches in cellular decisions under physiological conditions is often misregulated in tumors. Surprisingly, their functional implication in the initiation and progression of cancer may be either dependent on Polycomb complexes, or specific for a subunit that acts independently of other PcG members. In this review, we describe how misregulated Polycomb proteins play a pleiotropic role in cancer by altering a broad spectrum of biological processes such as the proliferation-differentiation balance, metabolism and the immune response, all of which are crucial in tumor progression. We also illustrate how interfering with PcG functions can provide a powerful strategy to counter tumor progression.

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.

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.

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.

Significance of chromobox protein (CBX) expression in diffuse LBCL

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the main pathological type of non-Hodgkin lymphoma (NHL). Chromobox (CBX) family proteins are classical components of polycomb group (PcG) complexes in many cancer types, resulting in accelerated carcinogenesis. Nevertheless, the prognostic, functional and expression significance of these CBX family members in DLBCL remain unclear and elusive.

METHODS

CBX transcriptional levels were confirmed using Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA) and Cancer Cell Line Encyclopedia (CCLE) databases. The protein levels of CBX family members were analysed using The Human Protein Atlas (HPA) database. Information on the PPI network, functional enrichment, drug sensitivity, prognostic value, miRNA network, protein structure, genetic alteration and immune cell infiltration were generated using the GeneMANIA, Metascape, GSCALite, GEPIA, PDB, cBioPortal, and TIMER databases, and the correlation of these factors with CBX expression levels in DLBCL was assessed.

RESULTS

CBX1/2/3/5/6/8 mRNA levels were significantly enhanced in DLBCL tissues compared to corresponding normal tissues. CBX1/3/4/5/8 protein expression levels were obviously increased, whereas CBX7 was obviously decreased. This difference might be attributed to miRNA regulation based on the miRNA network. Overall survival (OS) analysis showed that CBX levels were not correlated with prognosis in DLBCL patients, indicating that CBXs are not good biomarkers for DLBCL patients. Furthermore, functional enrichment analyses indicated that CBXs were closely related to DNA duplex unwinding, covalent chromatin modification, and histone lysine methylation. The levels of CBXs were also significantly associated with diverse immune cell infiltration in DLBCL.

CONCLUSIONS

This study reveals that dysregulated CBXs are involved in DLBCL development and might represent potential therapeutic targets for DLBCL.

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.

Evi1 upregulates Fbp1 and supports progression of acute myeloid leukemia through pentose phosphate pathway activation

Evi1 is a transcription factor essential for the development as well as progression of acute myeloid leukemia (AML) and high Evi1 AML is associated with extremely poor clinical outcome. Since targeting metabolic vulnerability is the emerging therapeutic strategy of cancer, we herein investigated a novel therapeutic target of Evi1 by analyzing transcriptomic, epigenetic, and metabolomic profiling of mouse high Evi1 leukemia cells. We revealed that Evi1 overexpression and Evi1‐driven leukemic transformation upregulate transcription of gluconeogenesis enzyme Fbp1 and other pentose phosphate enzymes with interaction between Evi1 and the enhancer region of these genes. Metabolome analysis using Evi1‐overexpressing leukemia cells uncovered pentose phosphate pathway upregulation by Evi1 overexpression. Suppression of Fbp1 as well as pentose phosphate pathway enzymes by shRNA‐mediated knockdown selectively decreased Evi1‐driven leukemogenesis in vitro. Moreover, pharmacological or shRNA‐mediated Fbp1 inhibition in secondarily transplanted Evi1‐overexpressing leukemia mouse significantly decreased leukemia cell burden. Collectively, targeting FBP1 is a promising therapeutic strategy of high Evi1 AML.

lncRNA KCNQ1OT1 reverses the effect of sevoflurane on hepatocellular carcinoma progression via regulating the miR-29a-3p/CBX3 axis

Sevoflurane (SEVO) is widely applied as an anesthetic, which exerts antitumor capacity in various cancers, including hepatocellular carcinoma (HCC). Previous studies indicated that long non-coding RNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) was upregulated, while microRNA-29a-3p (miR-29a-3p) was downregulated in HCC. Thus, we aimed to explore the roles of KCNQ1OT1 and miR-29a-3p in HCC cells exposed to SEVO. Cell proliferation, apoptosis, migration, and invasion were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and transwell assays, respectively. The levels of genes were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Furthermore, the interaction between miR-29a-3p and KCNQ1OT1 or chromebox protein homolog 3 (CBX3) was predicted by Starbase or Targetscan, and then confirmed by dual-luciferase reporter assay. We found that the levels of KCNQ1OT1 and CBX3 were decreased, while miR-29a-3p was increased in SEVO-treated HCC cells. KCNQ1OT1 overexpression weakened the inhibitory effects of SEVO on HCC cell proliferation, apoptosis, migration, and invasion. Interestingly, KCNQ1OT1 bound to miR-29a-3p, and miR-29a-3p targeted CBX3. KCNQ1OT1 upregulated CBX3 level by repressing miR-29a-3p expression. Furthermore, KCNQ1OT1 exerted tumor promotion in HCC cells via suppressing miR-29a-3p to regulate CBX3 expression. Collectively, our findings demonstrated that KCNQ1OT1 regulated the antitumor effects of SEVO on HCC cells through modulating the miR-29a-3p/CBX3 axis, providing a theoretical basis for the treatment of HCC.

TRIM47 accelerates aerobic glycolysis and tumor progression through regulating ubiquitination of FBP1 in pancreatic cancer

Increasing studies demonstrated that ubiquitination plays a vital role in the pathogenesis of pancreatic cancer, and targeting regulation of the ubiquitination process is a potential means for cancer treatment. However, the role of tripartite motif 47 (TRIM47) in pancreatic cancer is still unclear. Here, significantly upregulated TRIM47 and decreased FBP1 expressions were found in pancreatic cancer patient tissues and pointed to a lower survival rate. In addition, we show that TRIM47 was upregulated in pancreatic cancer cells and promoted cell proliferation in vitro and in vivo. Mechanistic investigations showed that TRIM47 promoted the aerobic glycolysis of pancreatic cancer cells, which was largely dependent on the direct binding to and ubiquitination of fructose-1, 6-biphosphatase (FBP1). Furthermore, the promotion of TRIM47 on the Warburg effect and pancreatic cancer progression was abolished by the overexpression of FBP1. Therefore, targeting TRIM47/FBP1 axis might provide a novel strategy to suppress the development of pancreatic cancer.

The LncRNA RP11-279C4.1 Enhances the Malignant Behaviour of Glioma Cells and Glioma Stem-Like Cells by Regulating the miR-1273g-3p/CBX3 Axis

Glioma is the most common type of solid tumour affecting the central nervous system, and the survival rate of patients with glioma is low. However, the mechanism associated with glioma progression remains unclear. Growing evidence suggests that lncRNAs play essential roles in the initiation and progression of tumours, including gliomas. In the present study, we identified and verified the expression of the novel lncRNA RP11-279C4.1 by analyzing the TANRIC database and performing qRT-PCR assays, the results of which revealed its upregulation in glioma tissues and cell lines. The results of multiple functional experiments demonstrated that RP11-279C4.1 knockdown inhibited glioma malignant phenotypes, including cell proliferation, migration, invasion and cell self-renew ability in vitro. In addition, RP11-279C4.1 downregulation suppressed tumour growth in vivo. Mechanistically, RP11-279C4.1 induced CBX3 activation via competitively sponging miR-1273g-3p, and rescue assay results confirmed the importance of the RP11-279C4.1/miR-1273g-3p/CBX3 axis. Overall, the results of our present study demonstrated that RP11-279C4.1 functions as an oncogene that promotes tumour progression by modulating the miR-1273g-3p/CBX3 axis in glioma, suggesting that RP11-279C4.1 may be a novel therapeutic target for glioma.

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.

Proteomic analysis of the anticancer effect of various extracts of endemicThermopsisturcica in human cervical cancer cells

Background/aim

Thermopsisturcica is a perennial species endemic to Turkey and different extracts of T. turcica have an antiproliferative effect on cancer cells, but there has not been any report on HeLa (human cervical cancer) cells.

Materials and methods

To get a better understanding of the molecular mechanism of anticancer activity of methanolic extracts of leaves (LE) and flowers (FE) of T. turcica, we employed 2-DE-based proteomics to explore the proteins involved in anticancer activity in HeLa cells.

Results

T. turcica extracts showed a potent cytotoxic effect on HeLa cells with the IC50 values of 1.75 mg/mL for LE and 3.25 mg/mL for FE. The induction of apoptosis by LE and FE was also consistent with increased expression of caspase mRNAs and DNA fragmentation. In terms of the proteomic approach, 27 differentially expressed proteins were detected and identified through MALDI-TOF/TOF mass spectrometry. These altered proteins were involved in cytoskeleton organization and movement, protein folding, proteolysis and translation, cell cycle and proliferation, signal transduction, cell redox homeostasis, and metabolism.

Conclusion

Up-regulation of protein disulfide isomerases and down-regulation of Rho GDP-dissociation inhibitor, heterogeneous nuclear ribonucleoproteins, and heat shock proteins may contribute to the induction of apoptosis and arresting of the cell cycle in HeLa cells.

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.

Expression and prognostic value of Chromobox family members in gastric cancer

Background

The Chromobox (CBX) protein family, which is a crucial part of the epigenetic regulatory complex, plays an important role in the occurrence and development of cancer; however, the function and prognostic value of CBX family members in gastric cancer is not clear.

Methods

we investigated the relationship between CBX members and gastric cancer using a range of tools and databases: Oncomine, Kaplan-Meier plotter, cBioPortal, ULCAN, Metascape, and GEPIA.

Results

The results showed that, relative to normal gastric tissue, mRNA expression levels of CBX1-6 were significantly higher in gastric cancer tissue, whereas the level of CBX7 was significantly lower. Furthermore, overexpression of CBX3-6 and underexpression of CBX7 mRNAs was significantly related to the poor prognosis and survival of gastric cancer patients, making these CBX family members useful biomarkers. Finally, overexpression of CBX1 mRNA was significantly related to the poor prognosis of gastric cancer patients treated with adjuvant 5-fluorouracil-based chemotherapy.

Conclusions

The members of the CBX family can be used as prognosis and survival biomarkers for gastric cancer and CBX1 may be a biomarker for choosing the chemotherapy regimen of gastric cancer 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.

Glycolysis promotes the progression of pancreatic cancer and reduces cancer cell sensitivity to gemcitabine

Previous studies have reported that increased glycolytic activity enhances chemotherapy resistance in some types of malignancies. However, whether glycolysis influences the curative effect of gemcitabine (GEM) on pancreatic cancer (PC) cells remains unclear. The aim of this study was to investigate the status of glycolysis in PC and its association with tolerance to GEM. Data from The Cancer Genome Atlas (TCGA) were used to analyze the correlation between glycolysis-related gene (GRG) expression and PC progression and prognosis. 2-Deoxy-D-glucose (2-DG) was applied to assess the effect of glycolysis inhibition on PC cell death and GEM tolerance. Expression of some GRGs, such as HK1, GAPDH, PKM2, and LDHA, was significantly associated with the prognosis of PC. Furthermore, HK1, PKLR, and LDHA expression correlated positively with PC progression. Further analysis revealed that cancer cell death was markedly enhanced following glycolysis inhibition and that the sensitivity of cancer cells to GEM was notably increased in the presence of 2-DG. Our findings indicate that abnormally increased glycolytic activity promotes the development of PC and enhances drug tolerance to GEM. 2-DG combined with GEM is a potential therapy for PC.

CBX3/HP1γ promotes tumor proliferation and predicts poor survival in hepatocellular carcinoma

HP1γ, encoded by CBX3, is associated with cancer progression and patient prognosis. However, the prognostic value and functions of CBX3/HP1γ in hepatocellular carcinoma (HCC) remain unclear. Here, we performed a bioinformatics analysis using the Oncomine, TCGA and Human Protein Atlas databases, the Kaplan-Meier plotter, and the UALCAN web-portal to explore the expression and prognostic significance of CBX3/HP1γ in patients with different cancers, including liver cancer. HCC tissues and microarrays containing 354 samples were examined using immunohistochemical staining, quantitative real-time polymerase chain reaction, and Western blotting. CBX3-overexpression HCC cell lines were tested in proliferation assays to determine the function of CBX3/HP1γ. We found that CBX3/HP1γ was upregulated in many cancers and was associated with poor prognosis. Our results also revealed that CBX3/HP1γ is elevated in HCC tissues and is associated with malignant clinicopathological characteristics. Kaplan-Meier and Cox regression analyses verified that high CBX3/HP1γ expression is an independent and significant prognostic factor for reduced overall survival in HCC patients. Moreover, invitro functional assays showed that CBX3/HP1γ overexpression promotes HCC cell proliferation. These findings suggest that CBX3/HP1γ is an important oncogene in HCC that might act as a useful biomarker for prognosis and targeted therapy.

CBX3 predicts an unfavorable prognosis and promotes tumorigenesis in osteosarcoma

CBX3, namely chromobox protein homolog 3, a member of the heterochomatin protein 1 (HP1) family, has been shown to be associated with the tumorigenesis of various types of cancer. The aim of the present study was to assess the biological role and the clinicopathological importance of CBX3 in osteosarcoma. The Oncomine database was utilized to determine the CBX3 expression in sarcoma patients. A retrospective cohort study was conducted to evaluate the prognostic value of CBX3 expression. In addition, correlations between the clinicopathological features of the osteosarcoma patients and CBX3 expression were assessed and involved recurrence, distant metastasis, lymph node metastasis, response to chemotherapy, pathological differentiation, clinical stage, anatomic location, tumor size and age. To investigate the function of CBX3 in osteosarcoma, a small interfering RNA for CBX3 was designed and this was used for the transfection of osteosarcoma MG63 cells. Then, the effects of CBX3 on proliferation, cell cycle distribution and apoptosis of osteosarcoma cells were investigated via CCK-8 assay and cell cycle assay and cell apoptosis analysis, respectively. Based on our findings, upregulation of CBX3 expression was noted both in osteosarcoma and also other sarcoma types, which included pleomorphic liposarcoma, myxofibrosarcoma, myxoid/round cell liposarcoma and dedifferentiated liposarcoma. In addition, based on the retrospective cohort study, CBX3 expression was associated with the disease-free survival (DFS) and overall survival (OS) of the osteosarcoma patients and a large tumor size, high distant metastasis rate and high clinical stage rate. In addition, the proliferation ability was blocked by the knockdown of CBX3 through the application of CBX3 siRNA, and CBX3 knockdown also led to increased apoptosis and cell cycle arrest at G0 and G1 phases in osteosarcoma cells. CBX3 is highly expressed in human osteosarcoma tissues. Meanwhile, high CBX3 is a predictor of the poor prognosis of osteosarcoma patients. To conclude, the growth of osteosarcoma can be promoted by CBX3, which may be used as an independent potential prognostic biomarker for patients suffering from osteosarcoma.