Hsa_circ_0060937 accelerates non-small cell lung cancer progression via modulating miR-195-5p/HMGB3 pathway

Circ_100549 promotes tumor progression in lung adenocarcinoma through upregulation of BIRC6

Lung adenocarcinoma (LUAD) is a subtype of lung cancer with high incidence and mortality globally. Emerging evidence suggests that circular RNAs (circRNAs) exert critical functions in human cancers, including LUAD. CircRNA_100549 (circ_100549) has been reported to be significantly upregulated in non-small cell lung cancer (NSCLC) samples, while its role in modulating LUAD progression remains to be explored. The current study aims at investigating the functional roles of circ_100549 in LUAD and its downstream molecular mechanism. First, we found that the expression of circ_100549 was higher in LUAD cell lines. Loss-of-function assays verified that depletion of circ_100549 repressed LUAD cell proliferation but accelerated cell apoptosis. Furthermore, in vivo experiments demonstrated that silencing of circ_100549 suppressed tumor growth. Subsequently, based on database analysis, we carried out a series of experiments to explore the mechanisms and effects of circ_100549 underlying LUAD progression, including RNA-binding protein immunoprecipitation (RIP), RNA/DNA pull-down, luciferase reporter, and chromatin immunoprecipitation (ChIP) assays. The results indicated that circ_100549 serves as a ceRNA by sponging miR-95-5p to upregulate BPTF expression, thus upregulating BIRC6 expression at a transcriptional level in LUAD. In summary, our study demonstrated that circ_100549 facilitates LUAD progression by upregulating BIRC6 expression.

Exosomal HMGB3 released by glioma cells confers the activation of NLRP3 inflammasome and pyroptosis in tumor-associated macrophages

BACKGROUND

Previous evidences has highlighted the pivotal role of NOD-like receptor family pyrin domain-containing 3 (NLRP3)-mediated inflammasomes and pyroptosis activation in driving tumor malignancy and shaping the tumor microenvironment. Herein, we aimed to elucidate the impact of high-mobility group box 3 (HMGB3) released in glioma-derived exosomes on macrophage infiltration in gliomas, NLRP3 inflammasome activation and polarization.

METHODS

Transcripts and protein levels of HMGB3, and cytokines associated with macrophage phenotypes and pyroptosis were assessed in glioma tissues and cell lines (U251, LN229, T98G, A172) using qRT-PCR and/or Western blot analysis. Exosomes secreted from LN229 and NHA cells were isolated via differential ultracentrifugation and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and analysis of exosome-related markers. PKH67 staining was employed to examine exosomes uptake by THP-1 differentiated macrophages. Flow cytometry was utilized to assess macrophage pyroptotic rates and polarization-related markers.

RESULTS

HMGB3 expression was elevated in glioma tissues, serum samples and tumor cell lines. Kaplan-Meier curves revealed a positive correlation between higher HMGB3 expression and poor overall survival and recurrence-free survival. Moreover, glioma tissues with increased HMGB3 expression exhibited significant upregulation of M2 macrophages markers (CD68, CD206, Arg1) and NLRP3 inflammasome components (NLRP3, IL-1β, ASC), suggesting that HMGB3 was closely associated with macrophage infiltration and NLRP3 inflammasome activation. Notably, HMGB3 was found to be enriched in glioma cell- secreted exosomes and could be internalized by macrophages. Knockdown of HMGB3 in glioma cell exosomes could restrain M2 macrophage polarization, NLRP3 inflammasome activation and pyroptosis.

CONCLUSION

These findings suggested that glioma cells secreted exosomal HMGB3 could facilitate macrophage M2 polarization, pyroptosis and inflammatory infiltration, indicating HMGB3 might be a poor prognosis factor for glioma.

miR-195b is required for proper cellular homeostasis in the elderly

Over the last decade we have witnessed an increasing number of studies revealing the functional role of non-coding RNAs in a multitude of biological processes, including cellular homeostasis, proliferation and differentiation. Impaired expression of non-coding RNAs can cause distinct pathological conditions, including herein those affecting the gastrointestinal and cardiorespiratory systems, respectively. miR-15/miR-16/miR-195 family members have been broadly implicated in multiple biological processes, including regulation of cell proliferation, apoptosis and metabolism within distinct tissues, such as heart, liver and lungs. While the functional contribution of miR-195a has been reported in multiple biological contexts, the role of miR-195b remains unexplored. In this study we dissected the functional role of miR-195b by generating CRISPR-Cas9 gene edited miR-195b deficient mice. Our results demonstrate that miR-195b is dispensable for embryonic development. miR-195b-/- mice are fertile and displayed no gross anatomical and/or morphological defects. Mechanistically, cell cycle regulation, metabolism and oxidative stress markers are distinctly impaired in the heart, liver and lungs of aged mice, a condition that is not overtly observed at midlife. The lack of overt functional disarray during embryonic development and early adulthood might be due to temporal and tissue-specific compensatory mechanisms driven by selective upregulation miR-15/miR-16/miR-195 family members. Overall, our data demonstrated that miR-195b is dispensable for embryonic development and adulthood but is required for cellular homeostasis in the elderly.

Circular RNA in Non-small Cell Lung Carcinoma: Identification of Targets and New Treatment Modalities

Despite availability of several treatment options for non-small cell lung cancer (NSCLC), such as surgery, chemotherapy, radiation, targeted therapy and immunotherapy, the survival rate of patients for five years is in the range of 22%. Therefore, identification of new targets and treatment modalities for this disease is an important issue. In this context, we screened the PubMed database for up-regulated circular RNAs (circRNAs) which promote growth of NSCLC in preclinical models in vitro as well as in vivo xenograft models in immuno-compromised mice. This approach led to potential targets for further validation and inhibition with small molecules or antibody-derived entities. In case of preclinical validation, the corresponding circRNAs can be inhibited with small interfering RNAs (siRNA) or short hairpin RNAs (shRNA). The identified circRNAs act by sponging microRNAs (miRs) preventing cleavage of the mRNA of the corresponding targets. We identified nine circRNAs up-regulating transmembrane receptors, five circRNAs increasing expression of secreted proteins, nine circRNAs promoting expression of components of signaling pathways, six circRNAs involved in regulation of splicing and RNA processing, six circRNAs up-regulating actin-related and RNA processing components, seven circRNAs increasing the steady-state levels of transcription factors, two circRNAs increasing high-mobility group proteins, four circRNAs increasing components of the epigenetic modification system and three circRNAs up-regulating protein components of additional systems.

Circ_LDLR promotes the progression of papillary thyroid carcinoma by regulating miR-1294/HMGB3 axis

Circular RNAs (circRNAs) have been found to be associated with the development and progression of cancers including papillary thyroid carcinoma (PTC). Circ_LDLR has been reported to be highly expressed in PTC, but its underlying mechanism of action has not been fully elucidated. This study aimed to investigate the role of circ_LDLR in PTC. The expression of circ_LDLR, miR-1294 and high mobility group box (HMGB) 3 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). CCK-8 assay and transwell assays were employed to value cell viability, invasion and migration abilities. Western blot assay was to detect HMGB3 protein expression. Luciferase reporter gene and pull down assay were used to validate the interaction between miR-1294 and HMGB3 or circ_LDLR. Circ_LDLR showed high expression levels in PTC tissues and cells and knockdown of it inhibited the growth, invasion, and migration of PTC cells. In addition, miR-1294 was considered as a downstream target of circ_LDLR, and inhibition of miR-1294 partially reversed the inhibitory effects of circ_LDLR knockdown on PTC cells growth, invasion, and migration. More importantly, HMGB3 was identified as a downstream target of miR-1294. Our findings suggest circ_LDLR may plays a promoting role in PTC by downregulating miR-1294 and upregulating HMGB3 expression. Therefore, circ_LDLR may serve as a valuable prognostic biomarker and therapeutic target for PTC.

RNF182 induces p65 ubiquitination to affect PDL1 transcription and suppress immune evasion in lung adenocarcinoma

BACKGROUND

The RING finger (RNF) proteins are a large group of ubiquitin ligases whose aberrant expression is often associated with disease progression. This study examines the function of RNF protein 182 (RNF182) in lung adenocarcinoma (LUAD) cells and its impact on p65 and programmed death ligand 1 (PDL1) regulation.

METHODS

Expression of RNF182, p65, and PDL1 in LUAD tissues and cells was measured using immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT-qPCR), and/or western blot (WB) assays. LUAD cells were induced to overexpress RNF182 and p65, followed by cell counting kit-8, colony formation, Transwell, and flow cytometry assays to evaluate the cells' malignant phenotype. Coimmunoprecipitation and WB assays were used to verify RNF182's effect on p65 ubiquitination. Chromatin immunoprecipitation-qPCR and luciferase assays were used to analyze p65's transcriptional regulation of PDL1. Coculture of LUAD with CD8⁺ cytotoxic T cells was performed to detect lactate dehydrogenase release and interferon-γ and interleukin-2 concentrations. LUAD cells were implanted in mice to analyze tumorigenicity.

RESULTS

RNF182 was poorly expressed, while p65 and PDL1 were highly expressed in LUAD tissues and cells. RNF182 overexpression suppressed the malignant properties of LUAD cells, and it promoted p65 ubiquitination and protein degradation. p65 activated PDL1 transcription. Overexpression of RNF182 suppressed the PDL1 expression, increased the cytotoxicity in LUAD cells cocultured with CD8⁺ T cells, and suppressed the tumorigenesis of cancer cells in vivo. However, these tumor-suppressive effects of RNF182 on LUAD cells were blocked by p65 restoration.

CONCLUSION

This research demonstrates that RNF182 induces p65 ubiquitination to suppress PDL1 transcription and immunosuppression in LUAD.

CircDLG1 promotes malignant development of non-small cell lung cancer through regulation of the miR-630/CENPF axis

BACKGROUND

Circular RNAs (circRNAs) have been reported to be crucial modulatory molecules in the etiology of non-small cell lung cancer (NSCLC). This study aimed to probe the precise role and mechanism of circRNA discs large MAGUK scaffold protein 1 (circDLG1) in the malignant progression of NSCLC.

METHODS

The abundances of circDLG1, miR-630, and centromere protein F (CENPF) mRNAs were gauged by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was tested in 3‑(4, 5‑dimethylthiazol-2-yl)-2, 5‑diphenyltetrazolium bromide (MTT) assay and 5‑ethynyl-2'-deoxyuridine (EdU)-incorporation assay. Cell apoptosis was analyzed by flow cytometry. Cell migration and invasion were assessed by transwell assay. Western blot was exploited to examine the levels of all proteins. The interaction between miR-630 and circDLG1 or CENPF was verified by dual-luciferase reporter, RNA pull-down, and/or RNA immunoprecipitation assays. Tumor xenograft assay and immunohistochemistry (IHC) were executed for the role of circDLG1 in tumor growth in vivo.

RESULTS

CircDLG1 and CENPF were highly expressed in NSCLC, while miR-630 was downregulated. CircDLG1 silencing repressed proliferation, migration, and invasion, and expedited apoptosis of NSCLC cells in vitro. Mechanistically, circDLG1 deficiency modulated NSCLC cell malignant development through interacting with miR-630. Furthermore, CENPF was targeted by miR-630, and circDLG1 could positively control CENPF expression through acting as an miR-630 sponge. Furthermore, CENPF overexpression reversed the repressive impacts of circDLG1 inhibition in the malignant behaviors of NSCLC cells. Besides, circDLG1 interference hindered tumor growth in vivo.

CONCLUSION

CircDLG1 knockdown could impede NSCLC advancement through modulating the miR-630/CENPF axis, manifesting as a promising molecular target for NSCLC treatment.

Circ_0060937 Contributes to the Development of Lung Cancer via Positively Regulating LAD1 Expression by Binding to miR-1304-5p

In view of the significance of circular RNA (circRNA) in multiple carcinogeneses, our study focused on circ_0060937 and investigated its function and molecular mechanism in lung cancer. Quantitative real-time PCR (qPCR) and western blot assays were applied for expression analysis of circ_0060937, miR-1304-5p, LAD1, and several marker proteins. Functional experiments, including colony formation assay, EdU assay, transwell analysis, sphere formation assay, and flow cytometry experiment, were conducted for cell behavior analysis. The putative binding relationship between circ_0060937 and miR-1304-5p was validated by dual-luciferase reporter experiment and pull-down analysis. Animal models were established to ascertain the role of circ_0060937. Upregulation of circ_0060937 was shown in lung cancer tissues and cell lines. Circ_0060937 downregulation repressed A549 and H1299 cell proliferative, migratory, invasive, and sphere formation abilities, and circ_0060937 absence also decelerated tumorigenesis in animal models. Circ_0060937 bound to miR-1304-5p to positively regulate LAD1 expression. The inhibitory effects of circ_0060937 absence on A549 and H1299 cell malignant behaviors were largely reversed by miR-1304-5p inhibition or LAD1 overexpression, hinting that circ_0060937 affected lung cancer progression via modulating the miR-1304-5p/LAD1 axis. Circ_0060937 downregulation decreased the expression of LAD1 by releasing miR-1304-5p to effectively repress lung cancer cell growth and in vivo tumorigenesis.

Expression, tumor immune infiltration, and prognostic impact of HMGs in gastric cancer

Background

In the past decade, considerable research efforts on gastric cancer (GC) have been expended, however, little advancement has been made owing to the lack of effective biomarkers and treatment options. Herein, we aimed to examine the levels of expression, mutations, and clinical relevance of HMGs in GC to provide sufficient scientific evidence for clinical decision-making and risk management.

Methods

GC samples were obtained from The Cancer Genome Atlas (TCGA). University of California Santa Cruz (UCSC) XENA, Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, STRING, LinkedOmics, and DAVID databases were employed. The "ggplot2" package in the R software (×64 3.6.3) was used to thoroughly analyze the effects of HMGs. qRT-PCR was performed to assess HMG levels in GC cell lines.

Results

A total of 375 GC tissues and 32 paraneoplastic tissues were analyzed. The levels of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN1, HMGN2, and HMGN4 expression were increased in GC tissues relative to normal gastric tissues. HMGA1, HMGA2, HMGB1, HMGB2, and HMGB3 were highly expressed in GC cell lines. The OS was significantly different in the group showing low expressions of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN2, HMGN3, and HMGN5. There was a significant difference in RFS between the groups with low HMGA2, HMGB3, and high HMGN2 expression. The levels of HMGA2, HMGB3, and HMGN1 had a higher accuracy for prediction to distinguish GC from normal tissues (AUC value > 0.9). HMGs were tightly associated with immune infiltration and tumor immune escape and antitumor immunity most likely participates in HMG-mediated oncogenesis in GC. GO and KEGG enrichment analyses showed that HMGs played a vital role in the cell cycle pathway.

Conclusions

Our results strongly suggest a vital role of HMGs in GC. HMGA2 and HMGB3 could be potential markers for prognostic prediction and treatment targets for GC by interrupting the cell cycle pathway. Our findings might provide renewed perspectives for the selection of prognostic biomarkers among HMGs in GC and may contribute to the determination of the optimal strategy for the treatment of these patients.

Roles and mechanisms of miR-195-5p in human solid cancers

Cancer persists as a worldwide disease that contributes to high morbidity and mortality rates. As a class of non-coding RNA, microRNAs (miRNAs) are one kind of important regulators in cancer and frequently implicated in tumor development and progression. Emerging experiments have suggested that miRNA-195-5p (miR-195-5p) can regulate neoplastic processes in many pathways. For instance, miR-195-5p can not only regulate proliferation, migration and invasion of tumor cells but also promote tumor cell apoptosis. Furthermore, low expression of miR-195-5p could induce drug resistance. Our review focuses on the expression of miR-195-5p in various tumors and elucidates the related mechanisms of which miR-195-5p participates in tumor biology, as well as summarizes the roles of miR-195-5p in tumor progression. We believe that miR-195-5p might have potential utility as a novel diagnostic biomarker and therapeutic target for cancer.

Circular RNA Pvt1 oncogene (CircPVT1) promotes the progression of papillary thyroid carcinoma by activating the Wnt/β-catenin signaling pathway and modulating the ratio of microRNA-195 (miR-195) to vascular endothelial growth factor A (VEGFA) expression

Circular RNAs (circRNAs) have been reported to be involved in the progression of papillary thyroid carcinoma (PTC). However, the role of circular RNA Pvt1 oncogene (circPVT1) in PTC has rarely been reported. In this study, we aimed to investigate the function and mechanism of circPVT1 in PTC. The expression level of circPVT1, miR-195 and VEGFA were determined by reverse transcription‑quantitative PCR (RT‑qPCR). Fisher's exact test was used to analyze the correlation between circPVT1 expression and PTC clinical features. Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) staining assay and transwell assay were conducted to evaluate the cell proliferation, migration and invasion ability. Dual-luciferase reporter and Western blot assay were conducted for evaluating the correlation between miR-195 and circPVT1 or VEGFA. The results of RT-PCR showed that the expression level of circPVT1 was significantly upregulated in PTC tissues and cell lines. After downregulating circPVT1 expression in PTC cells, the abilities of cell proliferation, migration, and invasion were obviously suppressed, and the Wnt/β-catenin signaling pathway was also repressed. Besides, miR-195 could both bind to PVT1 and VEGFA, while PVT1 could promote the expression of VEGFA by binding to miR-195. Downregulation of VEGFA expression in PTC cells revealed weakened cell proliferation, migration, and invasion capacities, and restrained Wnt/β-catenin signaling pathway. Therefore, we demonstrated that circPVT1 could promote VEGFA expression by sponging miR-195. CircPVT1 could serve as a molecule sponge for miR-195 and mediate the ceRNA network to promote the expression of VEGFA, thus contributed to the malignant progression of PTC.