Mediator Complex Subunit MED1 Protein Expression Is Decreased during Bladder Cancer Progression

MediatorWeb: a protein-protein interaction network database for the RNA polymerase II Mediator complex

The protein-protein interaction (PPI) network of the Mediator complex is very tightly regulated and depends on different developmental and environmental cues. Here, we present an interactive platform for comparative analysis of the Mediator subunits from humans, baker's yeast Saccharomyces cerevisiae, and model plant Arabidopsis thaliana in a user-friendly web-interface database called MediatorWeb. MediatorWeb provides an interface to visualize and analyze the PPI network of Mediator subunits. The database facilitates downloading the untargeted and unweighted network of Mediator complex, its submodules, and individual Mediator subunits to better visualize the importance of individual Mediator subunits or their submodules. Further, MediatorWeb offers network visualization of the Mediator complex and interacting proteins that are functionally annotated. This feature provides clues to understand functions of Mediator subunits in different processes. In an additional tab, MediatorWeb provides quick access to secondary and tertiary structures, as well as residue-level contact information for Mediator subunits in each of the three model organisms. Another useful feature of MediatorWeb is detection of interologs based on orthologous analyses, which can provide clues to understand the functions of Mediator complex in less explored kingdoms. Thus, MediatorWeb and its features can help the user to understand the role of Mediator complex and its subunits in the transcription regulation of gene expression.

Regulation of Med1 protein by overexpression of BAP1 in breast cancer cells

Med1 binds to a nuclear receptor and regulates transcription. Elevated Med1 protein expression promotes cancer growth in hormone-dependent breast and prostate cancers. Med1 protein expression was investigated by deubiquitinating enzymes (DUBs) overexpression in breast cancer cell lines. Various DNA constructs of SRT-DUBs were overexpressed in the MCF7 cell line, and Med1 protein expression was investigated by western blotting. The cell growth and in vitro invasion assay were performed in BRCA1-associated protein 1 (BAP1) wild type and mutant (C91A) overexpressed cells. Ubiquitination of the Med1 protein was observed, and Med1 protein expression and transcriptional activity were verified by various DUBs overexpressed. Although Med1 protein expression increased upon the overexpression of BAP1, it was not affected by the overexpression of BAP1 mutant (C91A). BAP1 was increased by the E2 treatment, which has an important effect on the breast cancer growth, and cell growth was decreased by BAP1 C91A overexpression. However, metastatic capacities were decreased by BAP1. In addition, the binding between the Med1 and the BAP1 protein was observed. These data suggested that BAP1 regulated Med1 protein expression in breast cancer cells and involved in cancer cell growth and metastasis by binding to Med1 protein.

Chromosome instability region analysis and identification of the driver genes of the epithelial ovarian cancer cell lines A2780 and SKOV3

Epithelial ovarian cancer (EOC) is one of the most prevalent gynaecological cancers worldwide. The molecular mechanisms of serous ovarian cancer (SOC) remain unclear and not well understood. SOC cases are primarily diagnosed at the late stage, resulting in a poor prognosis. Advances in molecular biology techniques allow us to obtain a better understanding of precise molecular mechanisms and to identify the chromosome instability region and key driver genes in the carcinogenesis and progression of SOC. Whole-exome sequencing was performed on the normal ovarian cell line IOSE80 and the EOC cell lines SKOV3 and A2780. The single-nucleotide variation burden, distribution, frequency and signature followed the known ovarian mutation profiles, without chromosomal bias. Recurrently mutated ovarian cancer driver genes, including LRP1B, KMT2A, ARID1A, KMT2C and ATRX were also found in two cell lines. The genome distribution of copy number alterations was found by copy number variation (CNV) analysis, including amplification of 17q12 and 4p16.1 and deletion of 10q23.33. The CNVs of MED1, GRB7 and MIEN1 located at 17q12 were found to be correlated with the overall survival of SOC patients (MED1: p = 0.028, GRB7: p = 0.0048, MIEN1: p = 0.0051), and the expression of the three driver genes in the ovarian cell line IOSE80 and EOC cell lines SKOV3 and A2780 was confirmed by western blot and cell immunohistochemistry.

CDCP1 expression is frequently increased in aggressive urothelial carcinoma and promotes urothelial tumor progression

The prognosis of patients with advanced urothelial carcinoma (UC) remains poor and improving treatment continues to be a major medical need. CUB domain containing protein 1 (CDCP1) is a known oncogene in various types of solid cancers and its overexpression is associated with impaired prognosis. However, its role in UC remains undetermined. Here we assessed the clinical relevance of CDCP1 in two cohorts of UC at different stages of the disease. Immunohistochemistry showed that CDCP1 is highly expressed in advanced UC, which significantly correlates with shorter overall survival. Importantly, the basal/squamous UC subtype showed significantly enriched CDCP1 at the mRNA and protein levels. The functional role of CDCP1 overexpression was assessed taking advantage of ex vivo organoids derived from the CDCP1^pcLSL/+ transgenic mouse model. Furthermore, CDCP1 knockout UC cell lines were generated using CRISPR/Cas9 technology. Interestingly, CDCP1 overexpression significantly induced the activation of MAPK/ERK pathways in ex vivo organoids and increased their proliferation. Similarly, CDCP1 knockout in UC cell lines reduced their proliferation and migration, concomitant with MAPK/ERK pathway activity reduction. Our results highlight the relevance of CDCP1 in advanced UC and demonstrate its oncogenic role, suggesting that targeting CDCP1 could be a rational therapeutic strategy for the treatment of advanced UC.

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.

MED10 Drives the Oncogenicity and Refractory Phenotype of Bladder Urothelial Carcinoma Through the Upregulation of hsa-miR-590

Background

Dysfunctional transcription machinery with associated dysregulated transcription characterizes many malignancies. Components of the mediator complex, a principal modulator of transcription, are increasingly implicated in cancer. The mediator complex subunit 10 (MED10), a vital kinase module of the mediator, plays a critical role in bladder physiology and pathology. However, its role in the oncogenicity, metastasis, and disease recurrence in bladder cancer (BLCA) remains unclear.

Objective

Thus, we investigated the role of dysregulated or aberrantly expressed MED10 in the enhanced onco-aggression, disease progression, and recurrence of bladder urothelial carcinoma (UC), as well as the underlying molecular mechanism.

Methods

Using an array of multi-omics big data analyses of clinicopathological data, in vitro expression profiling and functional assays, and immunocytochemical staining, we assessed the probable roles of MED10 in the progression and prognosis of BLCA/UC.

Results

Our bioinformatics-aided gene expression profiling showed that MED10 is aberrantly expressed in patients with BLCA, is associated with high-grade disease, is positively correlated with tumor stage, and confers significant survival disadvantage. Reanalyzing the TCGA BLCA cohort (n = 454), we showed that aberrantly expressed MED10 expression is associated with metastatic and recurrent disease, disease progression, immune suppression, and therapy failure. Interestingly, we demonstrated that MED10 interacts with and is co-expressed with the microRNA, hsa-miR-590, and that CRISPR-mediated knockout of MED10 elicits the downregulation of miR-590 preferentially in metastatic UC cells, compared to their primary tumor peers. More so, silencing MED10 in SW1738 and JMSU1 UC cell lines significantly attenuates their cell proliferation, migration, invasion, clonogenicity, and tumorsphere formation (primary and secondary), with the associated downregulation of BCL-xL, MKI67, VIM, SNAI1, OCT4, and LIN28A but upregulated BAX protein expression. In addition, we showed that high MED10 expression is a non-inferior biomarker of urothelial recurrence compared with markers of cancer stemness; however, MED10 is a better biomarker of local recurrence than any of the stemness markers.

Conclusion

These data provide preclinical evidence that dysregulated MED10/MIR590 signaling drives onco-aggression, disease progression, and recurrence of bladder UC and that this oncogenic signal is therapeutically actionable for repressing the metastatic/recurrent phenotypes, enhancing therapy response, and shutting down stemness-driven disease progression and relapse in patients with BLCA/UC.

CDK7 Predicts Worse Outcome in Head and Neck Squamous-Cell Cancer

HNSCC is the sixth most common cancer worldwide and the prognosis is still poor. Here, we investigated the prognostic implications of CDK7 and pMED1. Both proteins affect transcription, and their expression is altered throughout different tumor entities. pMED1 is phosphorylated by CDK7. Importantly, CDK7 and MED1 have been ascribed prognostic implications by various studies. However, their prognostic value in head and neck squamous-cell cancer (HNSCC) remains elusive. We applied immunohistochemical staining of CDK7 and pMED1 on our large and clinically well-characterized HNSCC tissue cohort comprising 419 patients. Software-aided quantification of staining intensity was performed as a measure of protein expression. The following results were linked to the clinicopathological features of our cohort and correlated in different tissue types (primary tumor, lymph node metastasis, distant metastasis, recurrence). Upregulation CDK7 was associated with worse 5-year overall survival as well as disease-free survival in HNSCC while being independent of other known prognostic factors such as p16-status. Also, CDK7 expression was significantly elevated in immune cell infiltrated tumors. In HNSCC CDK7 might serve as a novel prognostic marker to indicate the prognosis of patients. Furthermore, in vitro studies proved the feasibility of CDK7 inhibition with attenuating effects on cell proliferation underlining its remarkable translational potential for future therapeutic regimes.

Downstream Neighbor of SON (DONSON) Expression Is Enhanced in Phenotypically Aggressive Prostate Cancers

Simple Summary

Downstream neighbor of SON (DONSON) plays a crucial role in cell cycle progression and in maintaining genomic stability. We identified DONSON to be associated with an aggressive histopathological phenotype and unfavorable survival in prostate cancer (PCa) in different transcriptomic cohorts and on the protein level in our tissue microarray cohort. DONSON expression in the primary tumor was particularly strong in locally advanced, metastasized, and dedifferentiated carcinomas (TNM Stage, Gleason). Highly proliferating tumors exhibited a significant correlation to DONSON expression, and DONSON expression was notably upregulated in distant metastases and androgen-deprivation resistant metastases. In vitro, specific DONSON-knockdown significantly reduced the migration capacity in PC-3 and LNCaP, which further suggests a tumor-promoting role of DONSON in PCa. The results of our comprehensive expression analyses, as well as the functional data obtained after DONSON-depletion, lead us to the conclusion that DONSON is a promising prognostic biomarker with oncogenic properties in PCa.

Abstract

Downstream neighbor of Son (DONSON) plays a crucial role in cell cycle progression and in maintaining genomic stability, but its role in prostate cancer (PCa) development and progression is still underinvestigated. Methods: DONSON mRNA expression was analyzed with regard to clinical-pathological parameters and progression using The Cancer Genome Atlas (TCGA) and two publicly available Gene Expression Omnibus (GEO) datasets of PCa. Afterwards, DONSON protein expression was assessed via immunohistochemistry on a comprehensive tissue microarray (TMA). Subsequently, the influence of a DONSON-knockdown induced by the transfection of antisense-oligonucleotides on proliferative capacity and metastatic potential was investigated. DONSON was associated with an aggressive phenotype in the PCa TCGA cohort, two GEO PCa cohorts, and our PCa TMA cohort as DONSON expression was particularly strong in locally advanced, metastasized, and dedifferentiated carcinomas. Thus, DONSON expression was notably upregulated in distant and androgen-deprivation resistant metastases. In vitro, specific DONSON-knockdown significantly reduced the migration capacity in the PCa cell lines PC-3 and LNCaP, which further suggests a tumor-promoting role of DONSON in PCa. In conclusion, the results of our comprehensive expression analyses, as well as the functional data obtained after DONSON-depletion, lead us to the conclusion that DONSON is a promising prognostic biomarker with oncogenic properties in PCa.

Downstream neighbor of SON (DONSON) is associated with unfavorable survival across diverse cancers with oncogenic properties in clear cell renal cell carcinoma

A precise stratification of our patients is essential and can support clinicians to determine the right therapy. The aim of this study was to identify clinically relevant genes using The Cancer Genome Atlas (TCGA) datasets. A comprehensive pan-cancer analysis of 30 distinct tumor entities (N = 9022) identified the largely unknown gene Downstream neighbor of SON (DONSON) to be particularly associated with unfavorable overall survival in clear cell renal cell carcinoma (KIRC). This prognostic potential of DONSON was validated in an independent KIRC cohort via quantitative real-time PCR (n = 152). Further, DONSON protein expression was evaluated via immunohistochemical staining followed by quantitative image analysis using the image analysis software QuPath on a renal cancer tissue microarray (n = 270). Interestingly, DONSON overexpression was preferentially associated with poor survival in 9 of the 30 entities, suggesting tumor-independent oncogenic properties of this largely unknown gene. A particularly strong association of DONSON to an aggressive phenotype was evident in KIRC and proved to be a strong independent predictor of unfavorable overall survival in two additional cohorts on the mRNA and protein level. In our KIRC cell culture model, we observed a substantial attenuation of proliferative activity and migration capacity of the KIRC cells Caki1 and 769p. In conclusion, we identified DONSON as a robust biomarker for risk stratification in KIRC in three independent cohorts and provide evidence that DONSON is linked to a malignant phenotype in the KIRC cell culture model.

A functional genetic screen identifies the Mediator complex as essential for SSX2-induced senescence

The senescence response to oncogenes is believed to be a barrier to oncogenic transformation in premalignant lesions, and describing the mechanisms by which tumor cells evade this response is important for early diagnosis and treatment. The male germ cell-associated protein SSX2 is ectopically expressed in many types of cancer and is functionally involved in regulating chromatin structure and supporting cell proliferation. Similar to many well-characterized oncogenes, SSX2 has the ability to induce senescence in cells. In this study, we performed a functional genetic screen to identify proteins implicated in SSX2-induced senescence and identified several subunits of the Mediator complex, which is central in regulating RNA polymerase-mediated transcription. Further experiments showed that reduced levels of MED1, MED4, and MED14 perturbed the development of senescence in SSX2-expressing cells. In contrast, knockdown of MED1 did not prevent development of B-Raf- and Epirubicin-induced senescence, suggesting that Mediator may be specifically linked to the cellular functions of SSX2 that may lead to development of senescence or be central in a SSX2-specific senescence response. Indeed, immunostaining of melanoma tumors, which often express SSX proteins, exhibited altered levels of MED1 compared to benign nevi. Similarly, RNA-seq analysis suggested that MED1, MED4, and MED14 were downregulated in some tumors, while upregulated in others. In conclusion, our study reveals the Mediator complex as essential for SSX2-induced senescence and suggests that changes in Mediator activity could be instrumental for tumorigenesis.

The knockdown of the Mediator complex subunit MED15 restrains urothelial bladder cancer cells' malignancy

The Mediator complex, a multi-subunit protein complex, plays an integral role in regulating transcription. Genetic alterations of the mediator subunit 15 (MED15) in separate tumor entities have been described previously. However, till now, not much is known about the role of MED15 in urothelial bladder cancer (BCa). Using cBioPortal, database analysis was executed for the mRNA expression and survival analysis of MED15 in BCa. Immunohistochemistry (IHC) analysis against MED15 was performed on tissue microarrays with 18 benign, 126 BCa, and 38 metastases samples. The intensity evaluation was performed using a staining intensity score from 0 to 3 and associated with clinicopathological data. The BCa cell lines T24 and TCCSUP were used for the functional investigation. After the MED15 knockdown by small interfering (si)RNA, cell proliferation, migration and invasion were investigated. On the mRNA level, only a low number of alterations (2%) was found for MED15 in BCa. Due to the small count of events, there were no significant differences or tendencies in survival. For IHC, MED15 was found to have a higher expression in non-muscle invasive BCa compared with benign and muscle invasive BCa. For survival analysis, no significant differences between samples with or without overexpression of MED15 were found. In the functional analysis, proliferation, migration, and invasion were significantly reduced in BCa-cells following the transient siRNA-mediated MED15 knockdown. In summary, MED15 appears to play a role in the tumor parameters proliferation, migration, and invasion in BCa, but further investigations are necessary.

Silencing of MED27 inhibits adrenal cortical carcinogenesis by targeting the Wnt/β-catenin signaling pathway and the epithelial-mesenchymal transition process

This study aimed to explore the effect of MED27 on the expression of epithelial-mesenchymal transition (EMT)-related proteins and β-catenin in adrenal cortical carcinoma (ACC). The functional mechanism of MED27 on ACC processes was also explored. The expression of MED27 was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). siRNA was utilized to knockdown the expression of MED27. CCK8 assays were performed to evaluate SW-13 cell proliferation. Transwell assays were performed to assess the invasion ability, and wound healing assays were utilized to detect migration. A tumor xenograft mouse model was established to investigate the impact of silencing MED27 on tumor growth and metastasis. MED27 was highly expressed in ACC tissues and cells. Down-regulation of MED27 induced ACC cell apoptosis, and significantly attenuated ACC cell proliferation, invasion and metastasis in vivo and in vitro. MED27 knockdown regulated the expression of EMT-related proteins and Wnt/β-catenin signaling pathway-related proteins. Our study investigated the function and mechanism of MED27 and validated that MED27 plays a negative role in ACC occurrence and progression and could be utilized as a new therapeutic target in ACC prevention and treatment.