Loss of expression rather than cytoplasmic mislocalization of RUNX3 predicts worse outcome in non-small cell lung cancer

Oxidative Stress-Mediated RUNX3 Mislocalization Occurs Via Jun Activation Domain-Binding Protein 1 and Histone Modification

Runt domain transcription factor 3 (RUNX3) suppresses many different cancer types and is disabled by mutations, epigenetic repression, or cytoplasmic mislocalization. In this study, we investigated whether oxidative stress is associated with RUNX3 accumulation from the nucleus to the cytoplasm in terms of histone modification. Oxidative stress elevated histone deacetylase (HDAC) level and lowered that of histone acetyltransferase. In addition, oxidative stress decreased the expression of mixed lineage leukemia (MLL), a histone methyltransferase, but increased the expression of euchromatic histone-lysine N-methyltransferase 2 (EHMT2/G9a), which is also a histone methyltransferase. Moreover, oxidative stress-induced RUNX3 phosphorylation, Src activation, and Jun activation domain-binding protein 1 (JAB1) expression were inhibited by knockdown of HDAC and G9a, restoring the nuclear localization of RUNX3 under oxidative stress. Cytoplasmic RUNX3 localization was followed by oxidative stress-induced histone modification, activated Src along with RUNX3 phosphorylation, and induction of JAB1, resulting in RUNX3 inactivation.

Ubiquitylation of RUNX3 by RNA-binding ubiquitin ligase MEX3C promotes tumorigenesis in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common pathological type of lung cancer, but the early diagnosis rate is low. The RNA-binding ubiquitin ligase MEX3C promotes tumorigenesis in several cancers but its mechanism of action in LUAD is unclear. In this study, the biological activity of MEX3C was assessed in LUAD. MEX3C and RUNX3 mRNA levels in the tissues of LUAD patients were determined using reverse transcription‑quantitative PCR. The involvement of MEX3C in the growth and metastasis of LUAD cells was measured by EdU assay, CCK-8, colony formation, Transwell assay, TUNEL, and flow cytometry. Expression of apoptosis and epithelial-mesenchymal transition related proteins were determined using western blotting analysis. LUAD cells transfected with si-MEX3C were administered to mice subcutaneously to monitor tumor progression and metastasis. We found that MEX3C is strongly upregulated in LUAD tissue sections, and involved in proliferation and migration. A549 and H1299 cells had significantly higher levels of MEX3C expression compared to control HBE cells. Knockdown of MEX3C dramatically decreased cell proliferation, migration, and invasion, and accelerated apoptosis. Mechanistically, we demonstrate MEX3C induces ubiquitylation and degradation of tumor suppressor RUNX3. Moreover, RUNX3 transcriptionally represses Suv39H1, as revealed by RNA pull-down and chromatin immunoprecipitation assays. The in vivo mice model demonstrated that knockdown of MEX3C reduced LUAD growth and metastasis significantly. Collectively, we reveal a novel MEX3C-RUNX3-Suv39H1 signaling axis driving LUAD pathogenesis. Targeting MEX3C may represent a promising therapeutic strategy against LUAD.

RUNX3/H3K27me3 Co-Expression Defines a Better Prognosis in Surgically Resected Stage I and Postoperative Chemotherapy-Naive Non-Small-Cell Lung Cancer

The purpose of this study is to investigate the significance of RUNX3/H3K27me3 co-expression in surgically resected non-small-cell lung cancer (NSCLC) patients. Using tissue microarray (TMA), immunohistochemistry, fluorescent double immunostaining, and western blotting, 208 NSCLC and 5 benign pulmonary patients were studied of their expression of runt-related transcription factor 3 (RUNX3), trimethylated histone H3 at lysine 27 (H3K27me3), enhancer of zeste homolog 2 (EZH2), and Ki-67. Apoptotic index in cancerous tissue was evaluated via TdT-mediated dUTP-biotin nick end labeling (TUNEL). The correlation between clinicopathologic parameters and overall survival was determined by Cox regression and Kaplan–Meier survival estimates and log-rank test. GEPIA and KM plotter were used for validation of some survival analyses. As a result, together with other regular prognostic factors, RUNX3/H3K27me3 co-expression was found to be closely correlated with better prognosis in either pTNM-I or POCT-naive NSCLC patients, which might partially result from a higher cancerous apoptotic index. In conclusion, RUNX3/H3K27me3 co-expression defined some specific NSCLC population with better prognosis and longer OS and could probably be used as a biomarker in the prediction of better postoperative outcomes.

Association of Exosomal miR-210 with Signaling Pathways Implicated in Lung Cancer

MicroRNA is a class of non-coding RNA involved in post-transcriptional gene regulation. Aberrant expression of miRNAs is well-documented in molecular cancer biology. Extensive research has shown that miR-210 is implicated in the progression of multiple cancers including that of the lung, bladder, colon, and renal cell carcinoma. In recent years, exosomes have been evidenced to facilitate cell–cell communication and signaling through packaging and transporting active biomolecules such as miRNAs and thereby modify the cellular microenvironment favorable for lung cancers. MiRNAs encapsulated inside the lipid bilayer of exosomes are stabilized and transmitted to target cells to exert alterations in the epigenetic landscape. The currently available literature indicates that exosomal miR-210 is involved in the regulation of various lung cancer-related signaling molecules and pathways, including STAT3, TIMP-1, KRAS/BACH2/GATA-3/RIP3, and PI3K/AKT. Here, we highlight major findings and progress on the roles of exosomal miR-210 in lung cancer.

DGCR8/miR-106 Axis Enhances Radiosensitivity of Head and Neck Squamous Cell Carcinomas by Downregulating RUNX3

Purpose: Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent malignant tumor worldwide, and the radiotherapy effect is strongly associated with human papillomavirus (HPV) infection. Therefore, the aim of our study was to analyze the mechanism of HPV E7 and its effects on radiosensitivity in HNSCC cells. Methods: The mRNA expression of DiGeorge syndrome critical region gene 8 (DGCR8), has-miR-106a, and Runt-related transcription factor 3 (RUNX3) was examined by quantitative real-time PCR (RT-qPCR). The protein expression of DGCR8, E7, RUNX3, caspase-3/cleaved caspase-3, poly(ADP-ribose) polymerase (PARP)/cleaved PARP, and γH2AX was measured by Western blot. The expression level of DGCR8 was measured by immunofluorescence assay. Starbase database (http://starbase.sysu.edu.cn/) was used to analyze the correlation between has-miR-106a-5p and DGCR8. TargetScan database (http://www.targetscan.org/vert_72/) was adopted to calculate the prediction of binding sites. Radiosensitivity was evaluated through clone formation assays and Cell Counting Kit-8 (CCK-8) assays. Results: In our study, we found that the mRNA and protein expression levels of HPV E7 and DGCR8 in HPV-positive HNSCC cells were higher than those in HPV-negative cells. The expression of DGCR8 was increased in FaDu and UM-SCC-4 with E7 overexpression, while the expression of DGCR8 was decreased in UM-SCC-47 and UPCI-SCC-090 with E7 silence. The miR-106a expression was increased after DGCR8 overexpression in FaDu and UM-SCC-4. However, the miR-106a expression was decreased in UM-SCC-47 and UPCI-SCC-090 with E7 silence. In radiation conditions, clone formation assays found that less clones formed in FaDu and UM-SCC-4 cells subsequent to silencing DGCR8 or miR-106a than that in the control group, and more clones were formed in UM-SCC-47 and UPCI-SCC-090 cells overexpressing DGCR8 or miR-106a than that in the control group. Luciferase reporter gene assays verified that miR-106a targeted the 3' untranslated region (UTR) of RUNX3 mRNA. MiR-106a overexpression resulted in a decrease in RUNX3 expression, and miR-106a silence increased RUNX3 expression. Rescue experiments conducted with miR-106a inhibitor restored radiation resistance and reduced DNA damage in radiation condition. Conclusions: Our study indicated that HPV E7 activated DGCR8/miR-106a/RUNX3 axis to enhance radiation sensitivity and provided directions for targeted therapeutic interventions.

RUNX3 levels in human hematopoietic progenitors are regulated by aging and dictate erythroid-myeloid balance

Healthy bone marrow progenitors yield a co-ordinated balance of hematopoietic lineages. This balance shifts with aging toward enhanced granulopoiesis with diminished erythropoiesis and lymphopoiesis, changes which likely contribute to the development of bone marrow disorders in the elderly. In this study, RUNX3 was identified as a hematopoietic stem and progenitor cell factor whose levels decline with aging in humans and mice. This decline is exaggerated in hematopoietic stem and progenitor cells from subjects diagnosed with unexplained anemia of the elderly. Hematopoietic stem cells from elderly unexplained anemia patients had diminished erythroid but unaffected granulocytic colony forming potential. Knockdown studies revealed human hematopoietic stem and progenitor cells to be strongly influenced by RUNX3 levels, with modest deficiencies abrogating erythroid differentiation at multiple steps while retaining capacity for granulopoiesis. Transcriptome profiling indicated control by RUNX3 of key erythroid transcription factors, including KLF1 and GATA1 These findings thus implicate RUNX3 as a participant in hematopoietic stem and progenitor cell aging, and a key determinant of erythroid-myeloid lineage balance.

Lung Cancer Staging and Associated Genetic and Epigenetic Events

The first step in treating lung cancer is to establish the stage of the disease, which in turn determines the treatment options and prognosis of the patient. Many factors are involved in lung cancer staging, but all involve anatomical information. However, new approaches, mainly those based on the molecular biology of cancer, have recently changed the paradigm for lung cancer treatment and have not yet been incorporated into staging. In a group of patients of the same stage who receive the same treatment, some may experience unexpected recurrence or metastasis, largely because current staging methods do not reflect the findings of molecular biological studies. In this review, we provide a brief summary of the latest research on lung cancer staging and the molecular events associated with carcinogenesis. We hope that this paper will serve as a bridge between clinicians and basic researchers and aid in our understanding of lung cancer.

miR-106b-5p promotes aggressive progression of hepatocellular carcinoma via targeting RUNX3

Background and Objectives

The roles of microRNA(miR)‐106b‐5p in hepatocellular carcinoma (HCC) remain unclear. We aimed here to investigate the clinical significance of miR‐106b‐5p expression in HCC and its underlying mechanisms.

Methods

Expression levels of miR‐106b‐5p in 108 HCC clinical samples by quantitative real‐time reverse transcription PCR. Associations of miR‐106b‐5p expression with various clinicopathological features and patients' prognosis were evaluated by Chi‐square test, Kaplan‐Meier, and Cox proportional regression analyses, respectively. The target gene of miR‐106b‐5p and their functions in HCC cells were investigated by luciferase reporter, CCK‐8, and Transwell Matrigel invasion assays.

Results

miR‐106b‐5p expression was markedly higher in HCC tissues than in noncancerous adjacent liver tissues (P < .001). miR‐106b‐5p upregulation was significantly associated with advanced TNM stage (P = .02), short recurrence‐free (P = .005), and overall (P = .001) survivals. Importantly, miR‐106b‐5p expression was an independent predictor of poor prognosis (P < .05). RUNX3 was identified as a direct target gene of miR‐106b‐5p in HCC cells. Functionally, miR‐106b‐5p upregulation promoted the viability and invasion of HCC cells, while enforced RUNX3 expression reversed the oncogenic effects of miR‐106b‐5p overexpression.

Conclusions

miR‐106b‐5p may serve as a potent prognostic marker for tumor recurrence and survival of HCC patients. miR‐106b‐5p may exert an oncogenic role in HCC via regulating its target gene RUNX3.

miR-301a promotes lung tumorigenesis by suppressing Runx3

BACKGROUND

Our previous report demonstrated that genetic ablation of miR-301a reduces Kras-driven lung tumorigenesis in mice. However, the impact of miR-301a on host anti-tumor immunity remains unexplored. Here we assessed the underlying molecular mechanisms of miR-301a in the tumor microenvironment.

METHODS

The differentially expressed genes were identified by using deep sequencing. The immune cell counts, and cytokines expression were analyzed by realtime PCR, immunohistochemistry and flow cytometry. The role of miR-301a/Runx3 in lung tumor was evaluated on cell growth, migration and invasion. The function of miR-301a/Runx3 in regulating tumor microenvironment and tumor metastasis were evaluated in Kras transgenic mice and B16/LLC1 syngeneic xenografts tumor models.

RESULTS

In this work, we identified 1166 up-regulated and 475 down-regulated differentially expressed genes in lung tumor tissues between KrasLA2 and miR-301a-/-; KrasLA2 mice. Immune response and cell cycle were major pathways involved in the protective role of miR-301a deletion in lung tumorigenesis. Overexpression of the miR-301a target, Runx3, was an early event identified in miR-301a-/-; KrasLA2 mice compared to WT-KrasLA2 mice. We found that miR-301a deletion enhanced CD8+ T cell accumulation and IFN-γ production in the tumor microenvironment and mediated antitumor immunity. Further studies revealed that miR-301a deficiency in the tumor microenvironment effectively reduced tumor metastasis by elevating Runx3 and recruiting CD8+ T cells, whereas miR-301a knockdown in tumor cells themselves restrained cell migration by elevating Runx3 expression.

CONCLUSIONS

Our findings further underscore that miR-301a facilitates tumor microenvironment antitumor immunity by Runx3 suppression in lung tumorigenesis.

EZH2/Bcl-2 Coexpression Predicts Worse Survival in Diffuse Large B-cell Lymphomas and Demonstrates Poor Efficacy to Rituximab in Localized Lesions

Enhancer of zeste homolog 2 (EZH2) and Bcl-2 gene rearrangement or protein upregulation played pivotal roles in the carcinogenesis of various malignancies including lymphomas. However, EZH2/Bcl-2 expression pattern and its clinicopathologic/prognostic significance in diffuse large B-cell lymphoma (DLBCL) remain unclear. To identify the association among EZH2, Bcl-2, clinicopathologic parametres in DLBCL, 2 DLBCL patient sets (test cohort, n=85; validation cohort n=51) and DLBCL cell lines were studied by tumor tissue microarray (TMA), immunohistochemistry and western blot. The optimal cut-off of EZH2 was determined by X-tile program from test cohort, as was verified in validation cohort. The prognostic significance was determined via Kaplan-Meier survival estimates and log-rank tests. Consequently, EZH2 and Bcl-2 expression were both enhanced and positively correlated with each other (𝑃=0.001) in both DLBCL patients and cell lines. EZH2/Bcl-2 coexpression was associated with poor overall survival (OS) and progression-free survival (PFS) in all DLBCL patients (all P<0.05). Univariate analyses revealed that EZH2/Bcl-2 coexpression correlated to worse objective response rate (ORR), shorter OS and PFS in DLBCL patients treated with RCHOP while multivariate analysis indicated that only elevated LDH level (P=0.001) and presence of B symtom (P=0.008) rather than EZH2/Bcl-2 coexpression were associated with worse OS. No survival benefit from rituximab regimen had been demonstrated in the early-staged DLBCL patients with EZH2/Bcl-2 coexpression. While in the subgroup of III-IV stage, RCHOP regimen showed obvious better OS and PFS than CHOP (P=0.039 and 0.005). In conclusion, EZH2/Bcl-2 coexpression defines unrecognized subgroup of DLBCL patients with distinct epigenetic phenotype and worse outcome.

Determining the optimal cutoff point for lymph node density and its impact on overall survival in children with Wilms' tumor

Objective

Previous studies showed that the lymph node density (LND) was a predictor of survival in Wilms’ tumor (WT). However, the optimal LND cutoff point is controversial due to methodological shortcomings of previous studies, and no studies have shown the effect of LND on survival in children with WT. The purpose of this study was to remedy this situation.

Methods

We identified 376 children with WT. LND cutoff point was determined using the median value, the X-tile program, the survival-tree algorithm, and the time-dependent ROC curve analysis. Survival functions were estimated by the Kaplan–Meier method. We used Cox regression analysis to determine the impact of LND on survival. Smooth curve fitting between relative mortality risk and LND was performed.

Results

The LND cutoff point was 0.44, 0.65, 0.65, and 0.64 according to the median value, the X-tile program, the survival-tree algorithm, and the time-dependent ROC curve analysis, respectively. The 5-, 10-, and 20-year overall survival rates were 86.9%, 86.9%, and 84.7%, respectively, in the <0.44 group and 81.3%, 80.3%, and 80.3%, respectively, in the ≥0.44 group. Survival did not differ significantly between the two groups (P=0.185). The 5-, 10-, and 20-year overall survival rates were 87.8%, 87.8%, and 86.0%, respectively, in the < 0.65 or < 0.64 group and 76.5%, 75.1%, and 75.1%, respectively, in the ≥ 0.65 or ≥ 0.64 group. Children with the high LND had a significantly worse survival (P=0.011) if 0.64 or 0.65 was used for the stratification. LND was a significant predictor for overall survival in the multivariate Cox regression analysis (HR =1.797; 95% CI, 1.043–3.097; P=0.035). Smooth curve fitting suggested that the risk of mortality tended to be ascending with the increase in LND in general.

Conclusion

The three methods including the X-tile program, the survival-tree algorithm, and the time-dependent receiver operating characteristic (ROC) curve analysis are equivalent in their ability to stratify patients and clearly better than the median method. The results showed that the optimal LND cutoff point was around 0.65 and the LND was a reliable predictor of overall survival in children with WT.