Mediator subunit 23 overexpression as a novel target for suppressing proliferation and tumorigenesis in hepatocellular carcinoma

MED23 depletion induces premature senescence in NSCLC cells by interacting with BCLAF1 and then suppressing NUPR1 expression

Lung cancer is the leading cause of cancer death worldwide. 85 % of lung cancers are categorized by their histological types as a non-small cell lung cancer (NSCLC) subtype. While the MED23 subunit of the mediator complex has been implicated in lung cancer development, the precise underlying mechanism remains unclear. Our research indicates that elevated MED23 expression is linked to reduced overall survival rates in NSCLC. Depletion of MED23 triggers premature senescence in NSCLC cells. Furthermore, through co-IP and mass spectrometry analyses, we have identified BCLAF1 as a binding partner of MED23, with subsequent confirmation via PLA assays. Subsequently, NUPR1, a transcriptional cofactor known to induce premature senescence in lung cancer cells by disrupting autophagic processes, was validated as a downstream target of the MED23/BCLAF1 complex through RNA-seq and ChIP assays. Thus, the interaction between MED23 and BCLAF1 regulates NUPR1 expression, impacting autophagic flux and leading to premature senescence in NSCLC cells.

A new strategy for screening novel functional genes involved in reduction of lipid droplet accumulation

Lipid droplets (LDs) are organelles that store excess lipids and provide fatty acids for energy production during starvation. LDs are also essential for cellular maintenance, but excessive accumulation of LDs triggers various cancers in addition to metabolic diseases such as diabetes. In this study, we aimed to develop a strategy to identify new genes that reduces accumulation of LDs in cancer cells using an RNA interference (RNAi) screening system employing artificial sequence-enriched shRNA libraries. Monitoring LDs by fluorescent activated cell sorting, the subsequently collected cumulative LDs cells, and shRNA sequence analysis identified a clone that potentially functioned to accumulate LDs. The clone showed no identical sequence to human Refseq. It showed very similar sequence to seven genes by allowing three mismatches. Among these genes, we identified the mediator complex subunit 6 (MED6) gene as a target of this shRNA. Silencing of MED6 led to an increase in LD accumulation and expression of the marker genes, PLIN2 and DGAT1, in fatty cells. MED6 is a member of the mediator complex that regulates RNA polymerase II transcription through transcription factor II. Some mediator complexes play important roles in both normal and pathophysiological transcription processes. These results suggest that MED6 transcriptionally regulates the genes involved in lipid metabolism and suppresses LD accumulation.

MED23 pathogenic variant: genomic-phenotypic analysis

The mediator complex subunit 23 (MED23) gene encodes a protein that acts as a tail module mediator complex, a multi-subunit co-activator involved in several cellular activities. MED23 has been shown to have substantial roles in myogenesis and other molecular mechanisms. The functions of MED23 in the neurological system remain unclear and the clinical phenotype is not thoroughly described. Whole exome sequencing was used to identify a novel mutation in the MED23 gene. DNA capture probes using next-generation sequencing-based copy number variation analysis with Illumina array were performed. The clinical, demographic, neuroimaging, and electrophysiological data of the patients were collected, and similarly, the data of all reported cases in the literature were extracted to compare findings. Screening a total of 9,662 articles, we identified 22 main regulatory processes for the MED23 gene, including suppressive activity for carcinogenic processes. MED23 is also involved in the brain's neurogenesis and functions. The identified cases mainly presented with intellectual disability (87.5%) and developmental delay (50%). Seizures were present in only 18.75% of the patients. Slow backgrounds and spike and sharp-wave complexes were reported on the electroencephalogram (EEG) of a few patients and delayed myelination, thin corpus callosum, and pontine hypoplasia on magnetic resonance imaging (MRI). The MED23 gene regulates several processes in which its understanding promotes considerable therapeutic potential for patients. It is crucial to consider genetic and laboratory testing, particularly when encountering potential carriers. Intellectual disability and developmental delay are the most notable clinical signs with heterogeneous features on EEG and MRI.

LINC00921 reduces lung cancer radiosensitivity by destabilizing NUDT21 and driving aberrant MED23 alternative polyadenylation

Alternative polyadenylation (APA) plays a major role in controlling transcriptome diversity and therapeutic resistance of cancers. However, long non-coding RNAs (lncRNAs) involved in pathological APA remain poorly defined. Here, we functionally characterize LINC00921, a MED13L/P300-induced oncogenic lncRNA, and show that it is required for global regulation of APA in non-small cell lung cancer (NSCLC). LINC00921 shows significant potential for reducing NSCLC radiosensitivity, and high LINC00921 levels are associated with a poor prognosis for patients with NSCLC treated with radiotherapy. LINC00921 controls NUDT21 stability by facilitating binding of NUDT21 with the E3 ligase TRIP12. LINC00921-induced destabilization of NUDT21 promotes 3' UTR shortening of MED23 mRNA via APA, which, in turn, leads to elevated MED23 protein levels in cancer cells and nuclear translocation of β-catenin and thereby activates expression of multiple β-catenin/T cell factor (TCF)/lymphoid enhancer-binding factor (LEF)-regulated core oncogenes (c-Myc, CCND1, and BMP4). These findings highlight the importance of functionally annotating lncRNAs controlling APA and suggest the clinical potential of therapeutics for advanced NSCLC.

The Prognostic Value of AT-Rich Interaction Domain (ARID) Family Members in Patients with Hepatocellular Carcinoma

Objective

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies with a poor prognosis. The AT-rich interaction domain (ARID) family plays an essential regulatory role in the pathogenesis and progression of cancers. This study aims to evaluate the prognostic value and clinical significance of human ARID family genes in HCC.

Methods

ONCOMINE and The Cancer Genome Atlas (TCGA) databases were employed to retrieve ARIDs expression profile and clinicopathological information of HCC. Kaplan–Meier plotter and MethSurv were applied to the survival analysis of patients with HCC. CBioPortal was used to analyze genetic mutations of ARIDs. Gene Expression Profiling Interactive Analysis (GEPIA) and Metascape were used to perform hub gene identification and functional enrichment.

Results

Expression levels of 11 ARIDs were upregulated in HCC, and 2 ARIDs were downregulated. Also, 4 ARIDs and 5 ARIDs were correlated with pathologic stages and histologic grades, respectively. Furthermore, higher expression of ARID1A, ARID1B, ARID2, ARID3A, ARID3B, ARID5B, KDM5A, KDM5B, KDM5C, and JARID2 was remarkably correlated with worse overall survival of patients with HCC, and the high ARID3C/KDM5D expression was related to longer overall survival. Multivariate Cox analysis indicated that ARID3A, KDM5C, and KDM5D were independent risk factors for HCC prognosis. Moreover, ARIDs mutations and 127 CpGs methylation in all ARIDs were observed to be significantly associated with the prognosis of HCC patients. Besides, our data showed that ARIDs could regulate tumor-related pathways and distinct immune cells in the HCC microenvironment.

Conclusions

ARIDs present the potential prognostic value for HCC. Our findings suggest that ARID3A, KDM5C, and KDM5D may be the prognostic biomarkers for patients with HCC.

Integration of radiogenomic features for early prediction of pathological complete response in patients with triple-negative breast cancer and identification of potential therapeutic targets

Background

We established a radiogenomic model to predict pathological complete response (pCR) in triple-negative breast cancer (TNBC) and explored the association between high-frequency mutations and drug resistance.

Methods

From April 2018 to September 2019, 112 patients who had received neoadjuvant chemotherapy were included. We randomly split the study population into training and validation sets (2:1 ratio). Contrast-enhanced magnetic resonance imaging scans were obtained at baseline and after two cycles of treatment and were used to extract quantitative radiomic features and to construct two radiomics-only models using a light gradient boosting machine. By incorporating the variant allele frequency features obtained from baseline core tissues, a radiogenomic model was constructed to predict pCR. Additionally, we explored the association between recurrent mutations and drug resistance.

Results

The two radiomics-only models showed similar performance with AUCs of 0.71 and 0.73 (p = 0.55). The radiogenomic model had a higher predictive ability than the radiomics-only model in the validation set (p = 0.04), with a corresponding AUC of 0.87 (0.73–0.91).

Two highly frequent mutations were selected after comparing the mutation sites of pCR and non-pCR populations. The MED23 mutation p.P394H caused epirubicin resistance in vitro (p < 0.01). The expression levels of γ-H2A.X, p-ATM and p-CHK2 in MED23 p.P394H cells were significantly lower than those in wild type cells (p < 0.01). In the HR repair system, the GFP positivity rate of MED23 p.P394H cells was higher than that in wild-type cells (p < 0.01).

Conclusions

The proposed radiogenomic model has the potential to accurately predict pCR in TNBC patients. Epirubicin resistance after MED23 p.P394H mutation might be affected by HR repair through regulation of the p-ATM-γ-H2A.X-p-CHK2 pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03452-1.

A Predictive Model for Prognosis and Therapeutic Response in Hepatocellular Carcinoma Based on a Panel of Three MED8-Related Immunomodulators

The current tumor-node-metastasis (TNM) system is limited in predicting the survival and guiding the treatment of hepatocellular carcinoma (HCC) patients since the TNM system only focuses on the anatomical factors, regardless of the intratumoral molecule heterogeneity. Besides, the landscape of intratumoral immune genes has emerged as a prognostic indicator. The mediator complex subunit 8 (MED8) is a major polymerase regulator and has been described as an oncogene in renal cell carcinoma, but its pathophysiological significance of HCC and its contribution to the prognosis of HCC remain unclear. Here, we aimed to discuss the expression profile and clinical correlation of MED8 in HCC and construct a predictive model based on MED8-related immunomodulators as a supplement to the TNM system. According to our analyses, MED8 was overexpressed in HCC tissues and increased expression of MED8 was an indicator of poor outcome in HCC. The knockdown of MED8 weakened the proliferation, colony forming, and migration of HepG2 and Huh7 cells. Subsequently, a predictive model was identified based on a panel of three MED8-related immunomodulators using The Cancer Genome Atlas (TCGA) database and further validated in International Cancer Genome Consortium (ICGC) database. The combination of the predictive model and the TNM system could improve the performance in predicting the survival of HCC patients. High-risk patients had poor overall survival in TCGA and ICGC databases, as well as in subgroup analysis with early clinicopathology classification. It was also found that high-risk patients had a higher probability of recurrence in TCGA cohort. Furthermore, low-risk score indicated a better response to immunotherapy and drug therapy. This predictive model can be served as a supplement to the TNM system and may have implications in prognosis stratification and therapeutic guidance for HCC.

Identification of Therapeutic Targets and Prognostic Biomarkers among Genes from the Mediator Complex Family in the Hepatocellular Carcinoma Tumour-Immune Microenvironment

BACKGROUND

Hepatocellular carcinoma (HCC) is predominant among all types of primary liver cancers characterised by high morbidity and mortality. Genes in the mediator complex (MED) family are engaged in the tumour-immune microenvironment and function as regulatory hubs mediating carcinogenesis and progression across diverse cancer types. Whereas research studies have been conducted to examine the mechanisms in several cancers, studies that systematically focused on the therapeutic and prognostic values of MED in patients with HCC are limited.

METHODS

The online databases ONCOMINE, GEPIA, UALCAN, GeneMANIA, cBioPortal, OmicStudio, STING, Metascape, and TIMER were used in this study.

RESULTS

The transcriptional levels of all members of the MED family in HCC presented an aberrant high expression pattern. Significant correlations were found between the MED1, MED6, MED8, MED10, MED12, MED15, MED17, MED19, MED20, MED21, MED22, MED23, MED24, MED25, MED26, and MED27 expression levels and the pathological stage in the patients with HCC. The patients with high expression levels of MED6, MED8, MED10, MED17, MED19, MED20, MED21, MED22, MED24, and MED25 were significantly associated with poor prognosis. Functional enrichment analysis revealed that the members of the MED family were mainly enriched in the nucleobase-containing compound catabolic process, regulation of chromosome organisation, and transcriptional regulation by TP53. Significant correlations were found between the MED6, MED8, MED10, MED17, MED19, MED20, MED21, MED22, MED24, and MED25 expression levels and all types of immune cells (B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells). B cells and MED8 were independent predictors of overall survival. We found significant correlations between the somatic copy number alterations of the MED6, MED8, MED10, MED20, MED21, MED22, MED24, and MED25 molecules and the abundance of immune infiltrates.

CONCLUSIONS

Our study delineated a thorough landscape to investigate the therapeutic and prognostic potentials of the MED family for HCC cases, which yielded promising results for the development of immunotherapeutic drugs and construction of a prognostic stratification model.

Nanomedicine promotes ferroptosis to inhibit tumour proliferation in vivo

miR-101–3p may play a therapeutic role in various tumours. However, its anti-tumour mechanism remains unclear, and a definitive strategy to treat tumour cells in vivo is lacking. The objective of this study was to investigate the inhibitory mechanism of miR-101–3p on tumour cells and to develop relevant nanomedicines for in vivo therapy. The expression levels of miR-101–3p and its target protein TBLR1 in tumour tissues and cells were detected, and their relationship with ferroptosis was clarified. Furthermore, the efficacy of nanocarriers in achieving in vivo therapeutic gene delivery was evaluated. Nanomedicine was further developed, with the anti-proliferative in vivo therapeutic effect validated using a subcutaneous xenograft cancer model. The expression level of miR-101–3p negatively correlated with clinical tumour size and TNM stage. miR-101–3p restores ferroptosis in tumour cells by directly targeting TBLR1, which in turn promotes apoptosis and inhibits proliferation. We developed nanomedicine that can deliver miR-101–3p to tumour cells in vivo to achieve ferroptosis recovery, as well as to inhibit in vivo tumour proliferation. The miR-101–3p/TBLR1 axis plays an important role in tumour ferroptosis. Nanopharmaceuticals that increase miR-101–3p levels may be effective therapies to inhibit tumour proliferation.

miR-1-3p suppresses the epithelial-mesenchymal transition property in renal cell cancer by downregulating Fibronectin 1

Purpose

Renal cell cancer (RCC) is one of the primary causes of malignancy deaths all over the world. The most important cause of RCC-related mortality is metastasis. Epithelial-mesenchymal transition (EMT) plays an important role in metastasis of malignant tumors including RCC. miR-1-3p is confirmed to be decreased in many types of cancer. Nevertheless, the function of miR-1-3p in RCC metastasis and EMT process was still unclear.

Materials and methods

In this study, information from clinical investigation, in vitro study, and in vivo study discovered miR-1-3p expression character and its status in RCC. The character of miR-1-3p in invasive and metastatic properties in vitro and in vivo was also inspected in RCC cells and xenograft tumor model, and expression levels of EMT markers were evaluated in RCC cells and tissues.

Results

miR-1-3p was proved to be decreased in RCC cell lines and tissues compared with normal renal cells and tissues. miR-1-3p expression level in RCC tissues was closely related with capsulation, lymph node metastasis, and vascular invasion. miR-1-3p was found to be able to block the EMT process in A498 and CAKI-1 RCC cells and tumors. Luciferase reporter assay and expression level rescue assays were employed to reveal that miR-1-3p inhibited the invasion and migration property of RCC cells by directly targeting Fibronectin 1. Upregulation of Fibronectin 1 partially reversed the suppressive effect of miR-1-3p on EMT process.

Conclusion

In brief, this study has verified that miR-1-3p blocked the EMT process of RCC cells by reducing Fibronectin 1 expression. miR-1-3p/Fibronectin 1 axis may be considered as a new target for drug development of RCC.

By downregulating PBX3, miR-526b suppresses the epithelial-mesenchymal transition process in cervical cancer cells

Aim: Research on novel mutant genes may develop the treatment of cervical cancer (CC). The role of miRNA-526b in epithelial-mesenchymal transition (EMT) of CC was investigated. Methods: The role and the molecular mechanism of miRNA-526b in CC and its effect on EMT were analyzed in clinical specimens and oncology experiments. Results: miRNA-526b was proved to be decreased in CC and associated with malignant clinicopathological characters. The character of miRNA-526b in EMT was also inspected in CC cells and tumor models. miRNA-526b was found to be able to inhibit the EMT property of CC cells by directly targeting PBX3. Conclusion: miRNA-526b restoration may be deliberated as a new treatment strategy of CC.

Novel mutation in the MED23 gene for intellectual disability: A case report and literature review

MED23 deficiency causes the autosomal recessive Intellectual Disability (ID). Here we report an Iranian case with nonsyndromic ID presenting with developmental delay, microcephaly, hypotonia, severe ID, speech delay, and spasticity, who was homozygous for the novel MED23 c.670C>G variant. These results expand the clinical and mutation spectrum of MED23 deficiency.

miR-431-5p alters the epithelial-to-mesenchymal transition markers by targeting UROC28 in hepatoma cells

OBJECTIVE

MicroRNA (miR)-431 plays an essential role in various human cancer types, particularly in the process of invasion. However, the function and mechanism of miR-431-5p in the invasion of hepatocellular carcinoma (HCC) remain undefined.

METHODS

The expression levels of miR-431-5p and its potential target protein UROC28 in hepatocellular carcinoma cells and tissues were detected, and the levels of EMT markers in vivo and in vitro were also detected.

RESULTS

MiR-431-5p was downregulated in HCC cell lines and tissues and associated with vascular invasion and tumor encapsulation. Furthermore, miR-431-5p was able to influence the epithelialto-mesenchymal transition (EMT) process in HCCLM3 and HUH7 cells. Mechanistically, it was discovered that miR-431-5p repressed invasion by targeting UROC28. Furthermore, miR-431-5p influenced the EMT markers in HCCLM3 and HUH7 cells by downregulating UROC28 expression. Similarly, in vivo assays confirmed that miR-431-5p upregulation in HCC cells remarkably inhibited tumor proliferation and influenced the EMT markers.

CONCLUSION

The current study has demonstrated that the miR-431-5p/UROC28 axis acts possible influence on the EMT in HCC. Upregulation of miR-431-5p could be an original approach for inhibiting tumor invasion.

The Mediator complex subunit MED15, a promoter of tumour progression and metastatic spread in renal cell carcinoma

BACKGROUND/OBJECTIVE

MED15 is a part of the multiprotein Mediator complex which is involved in the transcription of polymerase (Pol) II-dependent genes. Several studies in this field have reported altered expressions of distinct subunits in human malignancy. However, the role of MED15 in renal cell carcinoma (RCC) has not be investigated yet.

METHODS

First, we performed an RNA expression and survival analysis of MED15 in RCC by using the database cBioPortal. To confirm these data on the protein level, we executed immunohistochemical (IHC) staining against MED15 on a tissue microarray containing 184 samples of the most common subtypes of the tumour at the various stages. Further, we performed functional analysis including proliferation, migration, and invasion assays on the RCC cell lines A-498 and ACHN following the siRNA-mediated MED15 knockdown.

RESULTS

On the mRNA level, higher expression of MED15 was associated with worse patient survival rates. IHC staining validated this tendency, unfortunately the results were not significant. However, supporting this tendency, in vitro-assays showed a significant decrease in proliferation, migration, and invasion after knockdown of MED15.

CONCLUSION

The research concludes that MED15 does seem to play a tumour promoting role in the progression and metastatic spread of renal cell carcinoma.

PBX3 is associated with proliferation and poor prognosis in patients with cervical cancer

Pre-B-cell leukemia homeobox 3 (PBX3) is upregulated in various malignancies; however, the role of PBX3 in cervical cancer (CC) is unknown. The purpose of this study was to explore the expression characteristics, clinicopathological significance, and molecular biological function of PBX3 in CC. The expression levels of PBX3 were analyzed in CC cell lines and tumor specimens by real-time polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical staining. The clinicopathological characteristics associated with PBX3 expression were evaluated. An RNA interference approach was employed to suppress PBX3 expression in CC in vitro and in vivo, determine its role in cell proliferation and analyze its molecular function. We found that PBX3 expression was significantly upregulated in CC cell lines and clinical specimens compared with normal cells and adjacent nontumorous cervical tissues. PBX3 was an independent predictive factor of poor prognosis, and its expression was correlated with tumor diameter, pathological grading, lymph node metastasis, invasion depth, vascular invasion, and clinical stage of CC. Multivariate analysis suggested that PBX3 expression may represent an independent prognostic indicator of the survival of CC patients. CC patients with high PBX3 expression exhibited reduced overall survival compared with those with low PBX3 expression. Additionally, stable downregulation of PBX3 expression in CC cell lines suppressed cell proliferation and decreased p-AKT protein expression levels in vitro. Similarly, in vivo assays demonstrated that PBX3 downregulation in CC cells markedly inhibited tumor size and weight. Overall, we demonstrated that PBX3 can promote CC cell proliferation via the AKT signaling pathway and that it may serve as a prognostic marker. Our data indicate that inactivation of PBX3 may be an effective clinical treatment for CC.

Dysregulation of Bmi1 promotes malignant transformation of hepatic progenitor cells

Adult hepatic progenitor cells (HPCs) are involved in a wide range of human liver diseases, including hepatocellular carcinoma (HCC). Bmi1 has been reported to have vital roles in stem cell self-renewal and carcinogenesis. We have previously demonstrated that Bmi1 is upregulated in HCC with bile duct tumor thrombi, a subtype of HCC characterized by profuse expression of hepatic stem cell markers. However, the function of Bmi1 in HPCs has not yet been well elucidated. The current study was designed to investigate the effects of Bmi1 on the biological properties of rat HPCs. To accomplish this, Bmi1 was silenced or enhanced in two HPC cell lines (WB-F344 and OC3) by, respectively, using either small interfering RNA against Bmi1 or a forced Bmi1 expression retroviral vector. The biological functions of Bmi1 in HPCs were investigated through cell proliferation assays, colony-formation assays, cell cycle analysis and invasion assays, as well as through xenograft-formation assays. In this study, genetic depletion of Bmi1 repressed cell proliferation, colony formation and invasion in both assessed HPC cell lines relative to controls. Conversely, forced expression of Bmi1 in two HPCs cell lines promoted cell proliferation, colony formation and invasion in vitro. Aldehyde dehydrogenase (ALDH) assay revealed a significant increase in the number of ALDH-positive cells following the forced expression of Bmi1 in HPCs. Most importantly, transplantation of forced Bmi1 expression HPCs into nude mice resulted in the formation of tumors with histological features of poorly differentiated HCC. Taken together, our findings indicate that forced expression of Bmi1 promotes the malignant transformation of HPCs, suggesting Bmi1 might be a potential molecular target for the treatment of HCC.