TRIM28 promotes tumor growth and metastasis in breast cancer by targeting the BRD7 protein for ubiquitination and degradation.

PURPOSE: Bromodomain-containing protein 7 (BRD7) is downregulated and functions as a tumor suppressor in many types of cancers including breast cancer, and the dysregulation of BRD7 expression is closely related to the development and progression of breast cancer. Whereas little attention has been focused on the regulation of BRD7 protein levels in breast cancer, which needs to be further elucidated. METHODS: The protein stability of BRD7 in breast cancer cells and BRD7 protein level in breast cancer tissues was examined by Western Blotting. The potential E3 ubiquitin ligase proteins that interact with the BRD7 was screened by coimmunoprecipitation combined with mass spectrometry analysis in MDA-MB-231 cells. We proved the interaction between BRD7 and tripartite motif containing 28 (TRIM28) through Co-Immunoprecipitation (Co-IP) and immunofluorescence assays. Co-IP and ubiquitination assay were used to explore the specific binding domain between BRD7 and TRIM28 and the ubiquitination site of BRD7. The effects of TRIM28 on the BRD7 protein stability and ubiquitination level was investigated by qPCR, Western Blot and Co-IP assay. CCK-8 and clone formation assays were carried out to assess the effect of TRIM28 on proliferation ability of breast cancer ells. Transwell assay and wound healing assay were used to investigate the effect of TRIM28 on breast cancer cell invasion and migration. Flow cytometry was used to detect the effect of TRIM28 on cell cycle and apoptosis of breast cancer cells. In addition, we confirmed effect of TRIM28 on tumor growth and metastasis by xenograft and metastatic mouse models. We designed some recovery assays to explore the role of recovery BRD7 in TRIM28-mediated promotion of malignant progression of breast cancer in vivo and in vitro. Finally, the clinical significance of TRIM28 and BRD7 was proved by immunohistochemistry. RESULTS: In this study, we demonstrated that BRD7 was an unstable protein and might be regulated by ubiquitination in breast cancer; furthermore, we found that the Coiled-Coil region of TRIM28 could directly bind to N-terminal of BRD7, and TRIM28 mediates BRD7 ubiquitination and degradation dependent on K21 by acting as a potential E3 ubiquitin ligase. Moreover, TRIM28 promoted cell proliferation, migration, invasion, xenograft tumor growth and metastasis, thus playing an oncogenic role in breast cancer. Furthermore, the restoration of BRD7 expression in breast cancer significantly reversed the promotional effects of TRIM28 on malignant progression both in vitro and in vivo. In addition, TRIM28 was highly expressed in the biopsy tissues of breast cancer, and its expression was negatively correlated with BRD7 expression and positively correlated with TNM stage and poor prognosis of BC patients. CONCLUSIONS: Our findings provide a novel mechanism by which TRIM28 significantly facilitates BRD7 ubiquitination and degradation, thus promoting breast cancer malignant progression. Targeting the TRIM28/BRD7 axis might be a novel potential strategy for the clinical diagnosis and treatment of breast cancer.

Ferroptosis: a critical mechanism of N6-methyladenosine modification involved in carcinogenesis and tumor progression.

Ferroptosis is an iron-dependent regulatory cell necrosis induced by iron overload and lipid peroxidation. It occurs when multiple redox-active enzymes are ectopically expressed or show abnormal function. Hence, the precise regulation of ferroptosis-related molecules is mediated across multiple levels, including transcriptional, posttranscriptional, translational, and epigenetic levels. N6-methyladenosine (m6A) is a highly evolutionarily conserved epigenetic modification in mammals. The m6A modification is commonly linked to tumor proliferation, progression, and therapy resistance because it is involved in RNA metabolic processes. Intriguingly, accumulating evidence suggests that dysregulated ferroptosis caused by the m6A modification drives tumor development. In this review, we summarized the roles of m6A regulators in ferroptosis-mediated malignant tumor progression and outlined the m6A regulatory mechanism involved in ferroptosis pathways. We also analyzed the potential value and application strategies of targeting m6A/ferroptosis pathway in the clinical diagnosis and therapy of tumors.

Validation of Core Ingredients and Molecular Mechanism of Cinobufotalin Injection Against Liver Cancer.

Purpose: Cinobufotalin injection has obvious curative effects on liver cancer patients with less toxicity and fewer side effects than other therapeutic approaches. However, the core ingredients and mechanism underlying these anti-liver cancer effects have not been fully clarified due to its complex composition. Methods: Multidimensional network analysis was used to screen the core ingredients, key targets and pathways underlying the therapeutic effects of cinobufotalin injection on liver cancer, and in vitro and in vivo experiments were performed to confirm the findings. Results: By construction of ingredient networks and integrated analysis, eight core ingredients and ten key targets were finally identified in cinobufotalin injection, and all of the core ingredients are tightly linked with the key targets, and these key targets are highly associated with the cell cycle-related pathways, supporting that both cinobufotalin injection and its core ingredients exert anti-liver cancer roles by blocking cell cycle-related pathways. Moreover, in vitro and in vivo experiments confirmed that either cinobufotalin injection or one of its core ingredients, cinobufagin, significantly inhibited cell proliferation, colony formation, cell cycle progression and xenograft tumor growth, and the key target molecules involved in the cell cycle pathway such as CDK1, CDK4, CCNB1, CHEK1 and CCNE1, exhibit consistent changes in expression after treatment with cinobufotalin injection or cinobufagin. Interestingly, some key targets CDK1, CDK4, PLK1, CHEK1, TTK were predicted to bind with multiple of core ingredients of cinobufotalin injection, and the affinity between one of the critical ingredients cinobufagin and key target CDK1 was further confirmed by SPR assay. Conclusion: Cinobufotalin injection was confirmed to includes eight core ingredients, and they play therapeutic effects in liver cancer by blocking cell cycle-related pathways, which provides important insights for the mechanism of cinobufotalin injection antagonizing liver cancer and the development of novel small molecule anti-cancer drugs.

Promoter A1312C mutation leads to microRNA-7 downregulation in human non-small cell lung cancer.

MicroRNA-7 (miRNA-7, miR-7) is a unique class of tumor suppressors, plays an important role in various physiological and pathological processes including human non-small cell lung cancer (NSCLC). In previous works, we revealed that miR-7 could regulate the growth and metastasis of human NSCLC cells. However, the mechanism of dysregulated miR-7 expression in NSCLC remains to be further elucidated. In this study, based on clinical sample analysis, we found that the downregulated expression of miR-7 was dominantly attributed to the decreased level of pri-miR-7-2 in human NSCLC. Furthermore, there were four site mutations in the miR-7-2 promoter sequence. Notably, among these four sites, mutation at -1312 locus (A â†’ C, termed as A1312C mutation) was dominate, and A1312C mutation further led to decreased expression of miR-7 in human NSCLC cells, accompanied with elevated transduction of NDUFA4/ERK/AKT signaling pathway. Mechanistically, homeobox A5 (HOXA5) is the key transcription factors regulating miR-7 expression in NSCLC. A1312C mutation impairs HOXA5 binding, thereby reducing the transcriptional activity of miR-7-2 promoter, resulting in downregulation of miR-7 expression. Together, these data may provide new insights into the dysregulation of specific miRNA expression in NSCLC and ultimately prove to be helpful in the diagnostic, prognostic, and therapeutic strategies against NSCLC.

Hierarchically porous cellulose-based carbon aerogels with N-doped skeletons and encapsulated iron-based catalysts for efficient tetracycline catalytic degradation.

Three-dimensional interpenetrating and hierarchically porous carbon material is an efficient catalyst support in water remediation and it is still a daunting challenge to establish the relationship between hierarchically porous structure and catalytic degradation performance. Herein, a highly porous silica (SiO2)/cellulose-based carbon aerogel with iron-based catalyst (FexOy) was fabricated by in-situ synthesis, freeze-drying and pyrolysis, where the addition of SiO2 induced the hierarchically porous morphology and three-dimensional interpenetrating sheet-like network with nitrogen doping. The destruction of cellulose crystalline structure by SiO2 and the iron-catalyzed breakdown of glycosidic bonds synergistically facilitated the formation of electron-rich graphite-like carbon skeleton. The unique microstructure is confirmed to be favorable for the diffusion of reactants and electron transport during catalytic process, thus boosting the catalytic degradation performance of carbon aerogels. As a result, the catalytic degradation efficiency of tetracycline under light irradiation by adding only 5 mg of FexOy/SiO2 cellulose carbon aerogels was as high as 90 % within 60 min, demonstrating the synergistic effect of photocatalysis and Fenton reaction. This ingenious structure design provides new insight into the relationship between hierarchically porous structure of carbon aerogels and their catalytic degradation performance, and opens a new avenue to develop cellulose-based carbon aerogel catalysts with efficient catalytic performance.

CircBRD7 attenuates tumor growth and metastasis in nasopharyngeal carcinoma via epigenetic activation of its host gene.

BRD7 was identified as a tumor suppressor in nasopharyngeal carcinoma (NPC). Circular RNAs (CircRNAs) are involved in the occurrence and development of NPC as oncogenes or tumor suppressors. However, the function and mechanism of the circular RNA forms derived from BRD7 in NPC are not well understood. In this study, we first identified that circBRD7 was a novel circRNA derived from BRD7 that inhibited cell proliferation, migration, invasion of NPC cells, as well as the xenograft tumor growth and metastasis in vivo. Mechanistically, circBRD7 promoted the transcriptional activation and expression of BRD7 by enhancing the enrichment of histone 3 lysine 27 acetylation (H3K27ac) in the promoter region of its host gene BRD7, and BRD7 promoted the formation of circBRD7. Therefore, circBRD7 formed a positive feedback loop with BRD7 to inhibit NPC development and progression. Moreover, restoration of BRD7 expression rescued the inhibitory effect of circBRD7 on the malignant progression of NPC. In addition, circBRD7 demonstrated low expression in NPC tissues, which was positively correlated with BRD7 expression and negatively correlated with the clinical stage of NPC patients. Taken together, circBRD7 attenuates the tumor growth and metastasis of NPC by forming a positive feedback loop with its host gene BRD7, and targeting the circBRD7/BRD7 axis is a promising strategy for the clinical diagnosis and treatment of NPC.

Impact of apolipoprotein A1 on tumor immune microenvironment, clinical prognosis and genomic landscape in hepatocellular carcinoma.

Background: Current knowledge on apolipoprotein A1 (APOA1) in hepatocellular carcinoma (HCC) is fragmented and even contradictory. Multi-dimensional analyses are required to comprehensively elucidate its value and underlying mechanism. Methods: We collected 49 RNA-seq datasets, 40 cell line types data and 70 scRNA pan-cancer datasets public available, including 17 HCC datasets (1754 tumor samples), and enrolled 73 pairs of HCC tissue and 516 blood samples independently from our clinics. APOA1 impacting on the HCC tumor microenvironment (TME) was analyzed using intensive data mining. Methylation sequencing, flow cytometry, quantitative PCR, western blot, immunohistochemistry and clinical chemistry assays were conducted for wet experimental investigation. Results: The APOA1 ontology fingerprint indicated that it played various crucial biological roles in HCC, primarily involved in cholesterol efflux. Consistent findings at histology, serology, and clinical follow-up revealed that high APOA1 was a good prognosis indicator of HCC. Hypermethylation in the APOA1 promoter region was found in clinical samples which is in accordance with the reduction of APOA1 in HCC. The cell cycle, DNA replication, mismatch repair pathways, and tumor cell proliferation were less observed in the HCC APOA1high subgroup. The favorable immunoregulatory abilities of APOA1 showed interesting findings: a positive correlation between APOA1 and anti-tumor immune cells (NK, CD8+ T cells) and a negative association with immune cells exerting immunosuppressive effects, including M2 macrophages. Conclusion: This is an integrative multidimensional exploration of APOA1 using bioinformatics and experiments. Both the prognostic value and anti-tumor effects based on APOA1 panoramic exploration in the HCC TME demonstrate a new potential clinical target for HCC assessment and intervention in the future.

Yin Yang 1 suppresses tumor invasion and metastasis in nasopharyngeal carcinoma by negatively regulating eIF4E transcriptional activity and expression.

Tumor metastasis is a leading cause of death in nasopharyngeal carcinoma (NPC) patients. Previous research has identified that transcription factor Yin Yang 1 (YY1) acts as a tumor suppressor that inhibits cell proliferation and tumor growth in NPC; however, the role and the molecular mechanisms of YY1 in NPC invasion and metastasis remain unclear. In this study, we discovered that YY1 could inhibit the migration and invasion of NPC cells in vitro as well as NPC xenograft tumor metastasis in vivo. Furthermore, we identified eIF4E as a direct downstream target of YY1, and YY1 could negatively regulate the expression of eIF4E at transcriptional level. Moreover, we found that eIF4E promoted the migration and invasion of NPC cells as well as NPC lung metastasis, suggesting its potential as a pro-metastatic mediator in NPC. Importantly, restoring eIF4E expression could partially reverse the inhibitory effects of YY1 on NPC malignancy. In consistent with these findings, the expression of YY1 was downregulated while eIF4E was upregulated in NPC patients with metastasis, and there was a negative correlation between YY1 and eIF4E expression. Collectively, our results indicate that YY1 suppresses the invasion and metastasis of NPC by negatively regulating eIF4E transcription. Therefore, targeting the YY1/eIF4E transcriptional axis could be a potential therapeutic strategy for the treatment of patients with NPC.

NOP2/Sun RNA methyltransferase 2 is a potential pan-cancer prognostic biomarker and is related to immunity.

BACKGROUND: NOP2/Sun RNA methyltransferase 2 (NSUN2), an important methyltransferase of m5C, has been poorly studied in cancers, and the relationship between NSUN2 and immunity remains largely unclear. Therefore, the purpose of this study was to explore the expression and prognostic value of NSUN2 and the role of NSUN2 in immunity in cancers. METHODS: The TIMER, CPTAC and other databases were used to analyze the expression of NSUN2, its correlation with clinical stage and its prognostic value across cancers. Moreover, the TISIDB, TIMER2.0 and Sangerbox platform were used to depict the relationships between NSUN2 and immune molecular subtypes, tumor-infiltrating lymphocytes (TILs), immune checkpoints (ICPs) and immunoregulatory genes. Furthermore, the NSUN2-interacting proteins and related genes as well as the coexpression networks of NSUN2 in LIHC, LUAD and HNSC were explored with the STRING, DAVID, GEPIA2 and LinkedOmics databases. Finally, the subcellular location and function of NSUN2 in HepG2, A549 and 5-8F cells were investigated by performing immunofluorescence, CCK-8 and wound healing assays. RESULTS: Overall, NSUN2 was highly expressed and related to a poor prognosis in most types of cancers and was also significantly associated with immune molecular subtypes in some cancer types. Furthermore, NSUN2 was significantly associated with the levels of ICPs and immunoregulatory genes. In addition, NSUN2 was found to be involved in a series of immune-related biological processes, such as the humoral immune response in LIHC and LUAD and T-cell activation and B-cell activation in HNSC. Immunofluorescence and CCK-8 assays also confirmed that NSUN2 was widely expressed in the nucleus and cytoplasm, and overexpression of NSUN2 promoted the proliferation and migration of HepG2, A549 and 5-8F cells. NSUN2 was also confirmed to positively regulate the expression of PD-L1. CONCLUSION: NSUN2 serves as a pan-cancer prognostic biomarker and is correlated with the immune infiltration of tumors.

Liver metastases across cancer types sharing tumor environment immunotolerance can impede immune response therapy and immune monitoring.

BACKGROUND: Hepatic immune tolerance might contribute to the development of therapeutic resistance to immunotherapy. However, addressing this issue is challenging since the efficacy of immunotherapy in the context of liver metastasis (LM) remains poorly studied. Here, we aimed to establish an LM common immune feature (LMCIF) score to quantify the characteristics of LM immunotolerance across cancer types for assisting clinical disease management. METHODS: Large-scale clinical data were collected to identify the prognosis of LM. Multi-omics datasets of metastatic cancers with LM special immune-related pathways (LMSIPs) from the Molecular Signatures Database (MSigDB)were used to obtain an LMCIF cluster. Based on differential expression genes (DEGs), a novel LMCIF score for the LMCIF cluster was constructed. In addition, multi-omics, and immunohistochemistry (IHC) data from the public and in-house cohorts were used to explore the features of LM, and LMCIF score. RESULTS: Patients with LM had a worse prognosis and significantly lower infiltration of immune cells than patients with metastasis to other organs when analyzed with combined clinical and RNA sequencing data. After extracting the LMCIF cluster from 373 samples by utilizing 29 LMSIPs and validating them in a microarray cohort, an LMCIF score was established to confirm the role of the immunosuppressive environment as a contributor to the poor prognosis of LM across cancer types. Moreover, this LMCIF score could be used to predict the immune response of cancer patients undergoing immunotherapy. Finally, we identified that the majority of the 31 LMCIF genes exhibited a negative correlation with TME cells in LM patients, one of them, KRT19, which possessed the strongest positive correlation with LMCIF score, was confirmed to have an immunosuppressive effect through IHC analysis. CONCLUSIONS: Our results suggest that LM across cancer types share similar immunological profiles that induce immunotolerance and escape from immune monitoring. The novel LMCIF score represents a common liver metastasis immune cluster for predicting immunotherapy response, the results of which might benefit clinical disease management.

Dissecting the roles and clinical potential of YY1 in the tumor microenvironment.

Yin-Yang 1 (YY1) is a member of the GLI-Kruppel family of zinc finger proteins and plays a vital dual biological role in cancer as an oncogene or a tumor suppressor during tumorigenesis and tumor progression. The tumor microenvironment (TME) is identified as the "soil" of tumor that has a critical role in both tumor growth and metastasis. Many studies have found that YY1 is closely related to the remodeling and regulation of the TME. Herein, we reviewed the expression pattern of YY1 in tumors and summarized the function and mechanism of YY1 in regulating tumor angiogenesis, immune and metabolism. In addition, we discussed the potential value of YY1 in tumor diagnosis and treatment and provided a novel molecular strategy for the clinical diagnosis and treatment of tumors.

Understanding the roles and regulation patterns of circRNA on its host gene in tumorigenesis and tumor progression.

Circular RNAs (circRNAs) are a novel type of endogenous non-coding RNAs, which are covalently closed loop structures formed by precursor mRNAs (pre-mRNAs) through back-splicing. CircRNAs are abnormally expressed in many tumors, and play critical roles in a variety of tumors as oncogenes or tumor suppressor genes by sponging miRNAs, regulating alternative splicing and transcription, cis-regulating host genes, interacting with RNA binding proteins (RBPs) or encoding polypeptides. Among them, the regulation of circRNAs on their corresponding host genes is a critical way for circRNAs to exit their functions. Accumulating evidence suggests that circRNAs are able to regulate the expression of host genes at the transcriptional level, post-transcriptional level, translational level, post-translational level, or by encoding polypeptides. Therefore, this paper mainly summarized the roles and association of circRNAs and their corresponding host genes in tumorigenesis and tumor progression, generalized the circRNAs that function synergistically or antagonistically with their host genes, and elaborated the mechanisms of mutual regulation between circRNAs and their host genes. More importantly, this review provides specific references for revealing the potential application of circRNAs combined with their host genes in tumor diagnosis, treatment and prognosis.

BRD7 inhibits enhancer activity and expression of BIRC2 to suppress tumor growth and metastasis in nasopharyngeal carcinoma.

BRD7 functions as a crucial tumor suppressor in numerous malignancies including nasopharyngeal carcinoma (NPC). However, its function and exact mechanisms involved in tumor progression are not well understood. Here, we found that the B7BS was a potential enhancer region of BIRC2, and BRD7 negatively regulated the transcriptional activity and expression of BIRC2 by targeting the activation of the BIRC2 enhancer. Moreover, BIRC2 promoted cell proliferation, migration, invasion as well as xenograft tumor growth and metastasis in vivo, thus functioning as an oncogene in NPC. Furthermore, the recovery of BIRC2 expression could rescue the inhibitory effect of BRD7 on cell proliferation, migration, invasion and xenograft tumor growth and metastasis. In addition, BIRC2 was highly-expressed in NPC tissues, and positively correlated with the TNM stage and negatively correlated with the expression of BRD7. Therefore, these results suggest that BRD7 suppresses tumor growth and metastasis thus functioning as a tumor suppressor at least partially by negatively regulating the enhancer activity and expression of BIRC2, and targeting the BRD7/BIRC2 regulation axis might be a potential strategy for the diagnosis and treatment of NPC.

Deciphering the vital roles and mechanism of m5C modification on RNA in cancers.

5-methylcytosine (m5C modification) plays an essential role in tumors, which affects different types of RNA, the expression of downstream target genes, and downstream pathways, thus participating in the tumor process. However, the effect of m5C modification on RNA in tumors and the exact mechanism have not been systematically reviewed. Therefore, we reviewed the status and sites of m5C modification, as well as the expression pattern and biological functions of m5C regulators in tumors, and further summarized the effects and regulation mechanism of m5C modification on messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), long non-coding RNA (lncRNA) and other RNA in tumors. Finally, we summed up the interaction network, potential application, and value in clinical diagnosis and treatment of tumors. Taken together, this review benefits revealing the mechanism of m5C modification in tumor progression and provides new strategies for tumor diagnosis and treatment.

Optimized thyroid transcription factor-1 core promoter-driven microRNA-7 expression effectively inhibits the growth of human non-small-cell lung cancer cells.

Targeted gene therapy has become a promising approach for lung cancer treatment. In our previous work, we reported that the targeted expression of microRNA-7 (miR-7) operated by thyroid transcription factor-1 (TTF-1) promoter inhibited the growth of human lung cancer cells in vitro and in vivo; however, the intervention efficiency needed to be further improved. In this study, we identified the core promoter of TTF-1 (from -1299 bp to -871 bp) by 5' deletion assay and screened out the putative transcription factors nuclear factor-1 (NF-1) and activator protein-1 (AP-1). Further analysis revealed that the expression level of NF-1, but not AP-1, was positively connected with the activation of TTF-1 core promoter in human non-small-cell lung cancer (NSCLC) cells. Moreover, the silencing of NF-1 could reduce the expression level of miR-7 operated by TTF-1 core promoter. Of note, we optimized four distinct sequences to form additional NF-1-binding sites (TGGCA) in the sequence of TTF-1 core promoter (termed as optTTF-1 promoter), and verified the binding efficiency of NF-1 on the optTTF-1 promoter by electrophoretic mobility shift assay (EMSA). As expected, the optTTF-1 promoter could more effectively drive miR-7 expression and inhibit the growth of human NSCLC cells in vitro, accompanied by a reduced transduction of NADH dehydrogenase (ubiquinone) 1α subcomplex 4 (NDUFA4)/protein kinase B (Akt) pathway. Consistently, optTTF-1 promoter-driven miR-7 expression could also effectively abrogate the growth and metastasis of tumor cells in a murine xenograft model of human NSCLC. Finally, no significant changes were detected in the biological indicators or the histology of some important tissues and organs, including heart, liver, and spleen. On the whole, our study revealed that the optimized TTF-1 promoter could more effectively operate miR-7 to influence the growth of human NSCLC cells, providing a new basis for the development of microRNA-based targeting gene therapy against clinical lung cancer.

The Emerging Roles and Clinical Potential of circSMARCA5 in Cancer.

Circular RNAs (circRNAs) are a type of endogenous non-coding RNA and a critical epigenetic regulation way that have a closed-loop structure and are highly stable, conserved, and tissue-specific, and they play an important role in the development of many diseases, including tumors, neurological diseases, and cardiovascular diseases. CircSMARCA5 is a circRNA formed by its parental gene SMARCA5 via back splicing which is dysregulated in expression in a variety of tumors and is involved in tumor development with dual functions as an oncogene or tumor suppressor. It not only serves as a competing endogenous RNA (ceRNA) by binding to various miRNAs, but it also interacts with RNA binding protein (RBP), regulating downstream gene expression; it also aids in DNA damage repair by regulating the transcription and expression of its parental gene. This review systematically summarized the expression and characteristics, dual biological functions, and molecular regulatory mechanisms of circSMARCA5 involved in carcinogenesis and tumor progression as well as the potential applications in early diagnosis and gene targeting therapy in tumors.

Mechanisms Controlling MicroRNA Expression in Tumor.

MicroRNAs (miRNAs) are widely present in many organisms and regulate the expression of genes in various biological processes such as cell differentiation, metabolism, and development. Numerous studies have shown that miRNAs are abnormally expressed in tumor tissues and are closely associated with tumorigenesis. MiRNA-based cancer gene therapy has consistently shown promising anti-tumor effects and is recognized as a new field in cancer treatment. So far, some clinical trials involving the treatment of malignancies have been carried out; however, studies of miRNA-based cancer gene therapy are still proceeding slowly. Therefore, furthering our understanding of the regulatory mechanisms of miRNA can bring substantial benefits to the development of miRNA-based gene therapy or other combination therapies and the clinical outcome of patients with cancer. Recent studies have revealed that the aberrant expression of miRNA in tumors is associated with promoter sequence mutation, epigenetic alteration, aberrant RNA modification, etc., showing the complexity of aberrant expression mechanisms of miRNA in tumors. In this paper, we systematically summarized the regulation mechanisms of miRNA expression in tumors, with the aim of providing assistance in the subsequent elucidation of the role of miRNA in tumorigenesis and the development of new strategies for tumor prevention and treatment.

Sparse logistic regression revealed the associations between HBV PreS quasispecies and hepatocellular carcinoma.

BACKGROUND: Chronic infection with hepatitis B virus (HBV) has been proved highly associated with the development of hepatocellular carcinoma (HCC). AIMS: The purpose of the study is to investigate the association between HBV preS region quasispecies and HCC development, as well as to develop HCC diagnosis model using HBV preS region quasispecies. METHODS: A total of 104 chronic hepatitis B (CHB) patients and 117 HBV-related HCC patients were enrolled. HBV preS region was sequenced using next generation sequencing (NGS) and the nucleotide entropy was calculated for quasispecies evaluation. Sparse logistic regression (SLR) was used to predict HCC development and prediction performances were evaluated using receiver operating characteristic curves. RESULTS: Entropy of HBV preS1, preS2 regions and several nucleotide points showed significant divergence between CHB and HCC patients. Using SLR, the classification of HCC/CHB groups achieved a mean area under the receiver operating characteristic curve (AUC) of 0.883 in the training data and 0.795 in the test data. The prediction model was also validated by a completely independent dataset from Hong Kong. The 10 selected nucleotide positions showed significantly different entropy between CHB and HCC patients. The HBV quasispecies also classified three clinical parameters, including HBeAg, HBVDNA, and Alkaline phosphatase (ALP) with the AUC value greater than 0.6 in the test data. CONCLUSIONS: Using NGS and SLR, the association between HBV preS region nucleotide entropy and HCC development was validated in our study and this could promote the understanding of HCC progression mechanism.

Single-cell N6-methyladenosine regulator patterns guide intercellular communication of tumor microenvironment that contribute to colorectal cancer progression and immunotherapy.

BACKGROUND: N6-methyladenosine (m6A) RNA methylation plays a critical role in key genetic events for various cancers; yet, how m6A functions within the tumor microenvironment (TME) remains to be elucidated. METHODS: A total of 65,362 single cells from single-cell RNA-seq data derived from 33 CRC tumor samples were analyzed by nonnegative matrix factorization (NMF) for 23 m6A RNA methylation regulators. CRC and Immunotherapy cohorts from public repository were used to determine the prognosis and immune response of TME clusters. RESULTS: The fibroblasts, macrophages, T and B cells were respectively grouped into 4 to 5 subclusters and then classified according to various biological processes and different marker genes. Furthermore, it revealed that the m6A RNA methylation regulators might be significantly related to the clinical and biological features of CRC, as well as the pseudotime trajectories of main TME cell types. Bulk-seq analysis suggested that these m6A-mediated TME cell subclusters had significant prognostic value for CRC patients and distinguished immune response for patients who underwent ICB therapy, especially for the CAFs and macrophages. Notably, CellChat analysis revealed that RNA m6A methylation-associated cell subtypes of TME cells manifested diverse and extensive interaction with tumor epithelial cells. Further analysis showed that ligand-receptor pairs, including MIF - (CD74 + CXCR4), MIF - (CD74 + CD44), MDK-NCL and LGALS9 - CD45, etc. mediated the communication between m6A associated subtypes of TME cells and tumor epithelial cells. CONCLUSIONS: Taken together, our study firstly revealed the m6A methylation mediated intercellular communication of the tumor microenvironment in the regulation of tumor growth and antitumor immunomodulatory processes.

The combined signatures of hypoxia and cellular landscape provides a prognostic and therapeutic biomarker in hepatitis B virus-related hepatocellular carcinoma.

Prognosis and treatment options of hepatitis B virus-related hepatocellular carcinoma (HBV-HCC) are generally based on tumor burden and liver function. Yet, tumor growth and therapeutic resistance of HBV-HCC are strongly influenced by intratumoral hypoxia and cells infiltrating the tumor microenvironment (TME). We, therefore, studied whether linking parameters associated with hypoxia and TME cells could have a better prediction of prognosis and therapeutic responses. Quantification of 109 hypoxia-related genes and 64 TME cells was performed in 452 HBV-HCC tumors. Prognostic hypoxia and TME cells signatures were determined based on Cox regression and meta-analysis for generating the Hypoxia-TME classifier. Thereafter, the prognosis, tumor, and immune characteristics as well as the benefit of therapies in Hypoxia-TME defined subgroups were analyzed. Patients in the Hypoxialow /TMEhigh subgroup showed a better prognosis and therapeutic responses than any other subgroups, which can be well elucidated based on the differences in terms of immune-related molecules, tumor somatic mutations, and cancer cellular signaling pathways. Notably, our analysis furthermore demonstrated the synergistic influence of hypoxia and TME on tumor metabolism and proliferation. Besides, the classifier allowed a further subdivision of patients with early- and late-HCC stages. In addition, the Hypoxia-TME classifier was validated in another independent HBV-HCC cohort (n = 144) and several pan-cancer cohorts. Overall, the Hypoxia-TME classifier showed a pretreatment predictive value for prognosis and therapeutic responses, which might provide new directions for strategizing patients with optimal therapies.