Med19 promotes bone metastasis and invasiveness of bladder urothelial carcinoma via bone morphogenetic protein 2

Bone Metastasis in Bladder Cancer

Bladder cancer (BCa) is the 10th most common and 13th most deadly malignancy worldwide. About 5% of BCa patients present initially with metastatic disease, with bone being the most diagnosed site for distant metastasis. The overall one-year survival of patients with BCa is 84%, whereas it is only 21% in patients with bone metastasis (BM). Metastasis of BCa cells to bone occurs by epithelial-to-mesenchymal transition, angiogenesis, intravasation, extravasation, and interactions with the bone microenvironment. However, the mechanism of BCa metastasis to the bone is not completely understood; it needs a further preclinical model to completely explain the process. As different imaging mechanisms, PET-CT cannot replace a radionuclide bone scan or an MRI for diagnosing BM. The management of BCa patients with BM includes chemotherapy, immunotherapy, targeted therapy, antibody-drug conjugates, bisphosphonates, denosumab, radioisotopes, and surgery. The objective of these treatments is to inhibit disease progression, improve overall survival, reduce skeletal-related events, relieve pain, and improve the quality of life of patients.

Identification and Quantification of Iron Metabolism Landscape on Therapy and Prognosis in Bladder Cancer

The morbidity of bladder cancer (BLCA) is high and has gradually elevated in recent years. BLCA is also characterized by high recurrence and high invasiveness. Due to the drug resistance and lack of effective prognostic indicators, the prognosis of patients with BLCA is greatly affected. Iron metabolism is considered to be a pivot of tumor occurrence, progression, and tumor microenvironment (TME) in tumors, but there is little research in BLCA. Herein, we used univariate COX regression analysis to screen 95 prognosis-related iron metabolism-related genes (IMRGs) according to transcription RNA sequencing and prognosis information of the Cancer Genome Atlas (TCGA) database. TCGA-BLCA cohort was clustered into four distinct iron metabolism patterns (C1, C2, C3, and C4) by the non-negative matrix factorization (NMF) algorithm. Survival analysis showed that C1 and C3 patterns had a better prognosis. Gene set variant analysis (GSVA) revealed that C2 and C4 patterns were mostly enriched in carcinogenic and immune activation pathways. ESTIMATE and single sample gene set enrichment analysis (ssGSEA) also confirmed the level of immune cell infiltration in C2 and C4 patterns was significantly elevated. Moreover, the immune checkpoint genes in C2 and C4 patterns were observably overexpressed. Studies on somatic mutations showed that the tumor mutation burden (TMB) of C1 and C4 patterns was the lowest. Chemotherapy response assessment revealed that C2 pattern was the most sensitive to chemotherapy, while C3 pattern was the most insensitive. Then we established the IMRG prognosis signature (IMRGscore) by the least absolute shrinkage and selection operator (LASSO), including 13 IMRGs (TCIRG1, CTSE, ATP6V0A1, CYP2C8, RNF19A, CYP4Z1, YPEL5, PLOD1, BMP6, CAST, SCD, IFNG, and ASIC3). We confirmed IMRGscore could be utilized as an independent prognostic indicator. Therefore, validation and quantification of iron metabolism landscapes will help us comprehend the formation of the BLCA immunosuppressive microenvironment, guide the selection of chemotherapeutic drugs and immunotherapy, and predict the prognosis of patients.

Mediator Complex Subunit 19 Promotes the Development of Hepatocellular Carcinoma by Regulating the AKT/mTOR Signaling Pathway

Background

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, the pathogenesis of which remains unclear. Mediator complex subunit 19 (MED19), a subunit of the Mediator complex, is a multi-protein co-activator necessary for DNA transcription factors to induce RNA polymerase II transcription. In the current study, we aimed to study the role of MED19 in HCC and elucidate its mechanism.

Methods

MED19 expression in HCC tissues was determined. The relationship between MED19 and the clinical prognosis was explored. The influence of MED19 on HCC cell viability, migration, invasion, and apoptosis was studied. The expression of AKT/mTOR pathway genes and proteins was detected by qRT-PCR and western blot. The correlation between MED19 and immune infiltration was investigated.

Results

MED19 was upregulated in HCC tissues compared with tumor-adjacent tissues, and was associated with a poor prognosis. Furthermore, high MED19 expression was correlated with race, gender, etc. Knockdown of MED19 inhibited cell proliferation, migration, invasion, and promoted apoptosis. Knockdown of MED19 decreased p-AKT and p-mTOR protein expression. Additionally, the downstream effectors of the AKT/mTOR pathway, p70S6K1 and 4EBP1, were affected by MED19. Notably, MED19 expression was positively correlated with the infiltration levels of B cells, CD4⁺ T cells, CD8⁺ T cells, macrophages, etc.

Conclusion

MED19 is significantly upregulated in HCC tissues and cells. MED19 may promote the progression of HCC in vitro and may be related to immune infiltration. Together, our data show that MED19 could be considered as a new possible biomarker as well as a novel therapeutic target for HCC.

Bone metastases from urothelial carcinoma. The dark side of the moon

Bone metastases are common in genitourinary cancers, but they are underreported and not well researched. Synchronous bone metastases occur in 1.39-5.5% of bladder cancer patients, while 30-40% of cases are metachronous. Bone morphogenetic proteins (BMPs) play a key role in regulating proliferation, migration and invasion of tumor cells in bone microenvironment of bone metastases from metastatic urothelial carcinoma (mUC). Bone metastases represent a poor prognostic factor due to high morbidity and mortality correlated to skeletal-related events (SREs). The incidence rate of SREs in bladder, renal pelvis, and ureteral cancer varies from 39 to 68%. Radiotherapy is the most frequent treatment for SREs. The early use of bone targeted therapies (BTT), zoledronic acid and denosumab, improves SREs incidence and morbidity and it seems to improve overall survival (OS). To date, several new agents (immunotherapy and targeted drugs) demonstrated efficacy in mUC. However, subgroup analysis for bone metastases is often not available, due to difficulties in analysing bone samples, non-RECIST lesions and delay in systemic treatment due to SREs that limit the enrolment of bone mUC patients in clinical trials. Larger solid tumor studies that included UC patients are the main source of data for the management of mUC patients with bone metastases. For these patients, multidisciplinary approach should be preferred, involving orthopaedics, radiotherapists and rehabilitation to improve outcome and quality of life. New prospective trials should characterize clinical and molecular features of patients with bone metastases and the impact of new drugs on this poor prognostic metastatic site.

The role of mediator complex subunit 19 in human diseases

Mediator is an evolutionarily conserved multi-protein complex that mediates the interaction between different proteins as a basic linker in the transcription mechanism of eukaryotes. It interacts with RNA polymerase II and participates in the process of gene expression. Mediator complex subunit 19 or regulation by oxygen 3, or lung cancer metastasis-related protein 1 is located at the head of the mediator complex; it is a multi-protein co-activator that induces the transcription of RNA polymerase II by DNA transcription factors. It is a tumor-related gene that plays an important role in transcriptional regulation, cell proliferation, and apoptosis and is closely related to the occurrence and development of the cancers of the lung, bladder, skin, etc. Here, we used the structure of mediator complex subunit 19 to review its role in tumor progression, fat metabolism, drug therapy, as well as the novel coronavirus, which has attracted much attention at present, suggesting that mediator complex subunit 19 has broad application in the occurrence and development of clinical diseases. As a tumor-related gene, the role and mechanism of mediator complex subunit 19 in the regulation of tumor growth could be of great significance for the diagnosis, prognosis, and treatment of mediator complex subunit 19 -related tumors.

Role of the BMP6 protein in breast cancer and other types of cancer

The BMP6 protein (Bone Morphogenetic Protein 6) is part of the superfamily of transforming growth factor-beta (TGF-β) ligands, participates in iron homeostasis, inhibits invasion by increasing adhesions and cell-cell type interactions and induces angiogenesis directly on vascular endothelial cells. BMP6 is coded by a tumor suppressor gene whose subexpression is related to the development and cancer progression; during neoplastic processes, methylation is the main mechanism by which gene silencing occurs. This work presents a review on the role of BMP6 protein in breast cancer (BC) and other types of cancer. The studies carried out to date suggest the participation of the BMP6 protein in the epithelial-mesenchymal transition (EMT) phenotype, cell growth and proliferation; however, these processes are affected in a variable way in the different types of cancer, the methylated CpG sites in BMP6 gene promoter, as well as the interaction with other proteins could be the cause of such variation.

Transcriptome Analysis of Ovarian and Uterine Clear Cell Malignancies

Purpose

Ovarian and uterine clear cell carcinomas (CCCs) are rare but associated with poor prognosis. This study explored RNA transcription patterns characteristic of these tumors.

Experimental Design

RNA sequencing (RNA-seq) of 11 ovarian CCCs and five uterine CCCs was performed and compared to publicly available data from high grade serous ovarian cancers (HGSOCs). Ingenuity Pathway Analyses were performed. CIBERSORT analyses estimated relative fractions of 22 immune cell types in each RNA-seq sample. Sequencing data was correlated with PD-L1 immunohistochemical expression.

Results

RNA-seq revealed 1,613 downregulated and 1,212 upregulated genes (corrected p < 0.05, |FC |≥10) in ovarian CCC versus HGSOC. Two subgroups were identified in the ovarian CCC, characterized by ethnicity and expression differences in ARID1A. There were 3,252 differentially expressed genes between PD-L1+/− ovarian CCCs, revealing immune response, cell death, and DNA repair networks, negatively correlated with PD-L1 expression, whereas cellular proliferation networks positively correlated with expression. In clear cell ovarian versus clear cell uterine cancer, 1,607 genes were significantly upregulated, and 109 genes were significantly downregulated (corrected p < 0.05, |FC|≥10). Comparative pathway analysis of late and early stage ovarian CCCs revealed unique metabolic and PTEN pathways, whereas uterine CCCs had unique Wnt/Ca+, estrogen receptor, and CCR5 signaling. CIBERSORT analysis revealed that activated mast cells and regulatory T cell populations were relatively enriched in uterine CCCs. The PD-L1+ ovarian CCCs had enriched resting NK cells and memory B cell populations, while PD-L1− had enriched CD8 T-cells, monocytes, eosinophils, and activated dendritic cells.

Conclusions

Unique transcriptional expression profiles distinguish clear cell uterine and ovarian cancers from each other and from other more common histologic subtypes. These insights may aid in devising novel therapeutics.

MED19 Regulates Adipogenesis and Maintenance of White Adipose Tissue Mass by Mediating PPARγ-Dependent Gene Expression

The Mediator complex relays regulatory signals from gene-specific transcription factors to the basal transcriptional machinery. However, the role of individual Mediator subunits in different tissues remains unclear. Here, we demonstrate that MED19 is essential for adipogenesis and maintenance of white adipose tissue (WAT) by mediating peroxisome proliferator-activated receptor gamma (PPARγ) transcriptional activity. MED19 knockdown blocks white adipogenesis, but not brown adipogenesis or C2C12 myoblast differentiation. Adipose-specific MED19 knockout (KO) in mice results in a striking loss of WAT, whitening of brown fat, hepatic steatosis, and insulin resistance. Inducible adipose-specific MED19 KO in adult animals also results in lipodystrophy, demonstrating its requirement for WAT maintenance. Global gene expression analysis reveals induction of genes involved in apoptosis and inflammation and impaired expression of adipose-specific genes, resulting from decreased PPARγ residency on adipocyte gene promoters and reduced association of PPARγ with RNA polymerase II. These results identify MED19 as a crucial facilitator of PPARγ-mediated gene expression in adipose tissue.

WNT/β-catenin signaling in urothelial carcinoma of bladder

Urothelial carcinoma of bladder is the second most prevalent genitourinary disease. It is a highly heterogeneous disease as it represents a spectrum of neoplasms, including non-muscle invasive bladder cancer (NMIBC), muscle invasive bladder cancer (MIBC) and metastatic lesions. Genome-wide approaches and candidate gene analysis suggest that malignant transformation of the bladder is multifactorial and a multitude of genes are involved in the development of MIBC or NMIBC phenotypes. Wnt signaling is being examined to control and maintain balance between stemness and differentiation in adult stem cell niches. Owing to its participation in urothelial development and maintenance of adult urothelial tissue homeostasis, the components of Wnt signaling are reported as an important diagnostic and prognostic markers as well as novel therapeutic targets. Mutations/epigenetic alterations in the key molecules of Wnt/β-catenin canonical pathway have been linked with tumorigenesis, development of drug resistance and enhanced survival. Present review extends our understanding on the functions of key regulatory molecules of canonical Wnt/β-catenin pathway in urothelial tumorigenesis by inducing cancer stem cell phenotype (UCSCs). UCSCs may be responsible for tumor heterogeneity, high recurrence rates and complex biological behavior of bladder cancer. Therefore, understanding the role of UCSCs and the regulatory mechanisms that are responsible for high relapse rates and metastasis could help to develop pathway inhibitors and augment current therapies. Potential implications in the treatment of urothelial carcinoma of bladder by targeting this pathway primarily in UCSCs as well as in bulk tumor population that are responsible for high relapse rates and metastasis may facilitate potential therapeutic avenues and better prognosis.

The Dual Role of Bone Morphogenetic Proteins in Cancer

Bone morphogenetic proteins (BMPs) are a diverse class of molecules with over 20 growth factor proteins that belong to the transforming growth factor-β (TGF-β) family and are highly associated with bone formation and disease development. Aberrant expression of various BMPs has been reported in several cancer tissues. Biological function studies have elicited the dual role of BMPs in both cancer development and suppression. Furthermore, a variety of BMP antagonists, ligands, and receptors have been shown to reduce or enhance tumorigenesis and metastasis. Knockout mouse models of BMP signaling components have also revealed that the suppression of BMP signaling impairs cancer metastasis. Herein, we highlight the basic clinical background and involvement of BMPs in modulating cancer progression and their dynamic interactions (e.g., with microRNAs) in the tumor microenvironment in addition to their mutations and roles in chemoprevention. We also suggest that BMPs should be considered a powerful putative therapeutic target in tumorigenesis and bone metastasis.

Nutlin-3a as a novel anticancer agent for adrenocortical carcinoma with CTNNB1 mutation

Adrenocortical carcinoma (ACC) is a rare malignancy, and CTNNB1 is frequently mutated in ACC. Our study aims to screen for effective agents with antineoplastic activity against ACC with CTNNB1 mutation. In‐silico screening of the Genomics of Drug Sensitivity in Cancer (GDSC) database was conducted. Drug sensitivity in cells with CTNNB1 mutation was analyzed and further in vitro and in vivo studies were performed using the compound. Only one compound, Nutlin‐3a, an MDM2 inhibitor, was significantly sensitive in 18 cancer cells with CTNNB1 mutation. Further analysis of the 18 cells revealed no significant efficacy between cells with both CTNNB1 and TP53 mutations indicating concomitant TP53 mutation did not impact on drug efficacy. We verified that Nutlin‐3a inhibited cellular proliferation in ACC cell line NCI‐H295R which harbored CTNNB1 mutation but not in SW13 cells which did not. Nutlin‐3a induced cell apoptosis and G1 cell‐cycle arrest in NCI‐H295R cells. Nutlin‐3a also decreased cellular migration and inhibited epithelial‐to‐mesenchymal transition (EMT) process in terms of EMT index. Nutlin‐3a resulted in decreased β‐catenin level independent of p53 level in NCI‐H295R but not SW13 cells. We also evaluated the effect of Nutlin‐3a on hormonal secretion of NCI‐H295R cells and found it resulted in decreased levels of cortisol, androgen, and progesterone. Nutlin‐3a treatment inhibited ACC tumor growth with no observed toxicity in mice in vivo. Our study has revealed that Nutlin‐3a potently inhibits ACC with CTNNB1 mutation. How p53/MDM2 axis coordinates with Wnt/beta‐Catenin signaling in ACC warrants further study.

ST6Gal-I overexpression facilitates prostate cancer progression via the PI3K/Akt/GSK-3β/β-catenin signaling pathway

ST6Gal-I sialyltransferase adds α2,6-linked sialic acids to the terminal ends of glycan chains of glycoproteins and glycolipids. ST6Gal-I is reportedly upregulated in many cancers, including hepatocellular carcinoma, ovarian cancer and breast cancer. However, the expression and function of ST6Gal-I in prostate cancer (PCa) and the mechanism underlying this function remain largely unknown. In this study, we observed that ST6Gal-I expression was upregulated in human PCa tissues compared to non-malignant prostate tissues. High ST6Gal-I expression was positively correlated with Gleason scores, seminal vesicle involvement and poor survival in patients with PCa. ST6Gal-I knockdown in aggressive prostate cancer PC-3 and DU145 cells significantly inhibited the proliferation, growth, migration and invasion capabilities of these cells. ST6Gal-I knockdown decreased the levels of several PI3K/Akt/GSK-3β/ β-catenin pathway components, such as p-PI3K, (Ser473)p-Akt, (Ser9)p-GSK-3β and β-catenin. Furthermore, targeting this pathway with a PI3K inhibitor or Akt RNA interference decreased p-Akt, p-GSK-3β and β-catenin expression, resulting in decreased PC-3 and DU145 proliferation, migration and invasion. Taken together, these results indicate that ST6Gal-I plays a critical role in cell proliferation and invasion via the PI3K/Akt/GSK-3β/β-catenin signaling pathway during PCa progression and that it might be a promising target for PCa prognosis determination and therapy.

BMP2 promotes proliferation and invasion of nasopharyngeal carcinoma cells via mTORC1 pathway

Bone morphogenetic protein-2 (BMP2) is a secreted protein that highly expressed in a variety of cancers and contributes to cell proliferation, migration, invasiveness, mobility, metastasis and EMT. However, its clinical significance and biological function in nasopharyngeal carcinoma (NPC) remain unknown up to now. Up-regulation of BMP2 was first observed in NPC cell lines by a genome-wide transcriptome analysis in our previous study. In this study, BMP2 mRNA was detected by qRT-PCR and data showed that it was upregulated in NPC compared with non-cancerous nasopharynx samples. Immunohistochemistry (IHC) analysis in NPC specimens revealed that high BMP2 expression was significantly associated with clinical stage, distant metastasis and shorter survival of NPC patients. Moreover, overexpression of BMP2 in NPC cells promoted cell proliferation, migration, invasiveness and epithelial-mesenchymal transition (EMT). Mechanistically, BMP2 overexpression increase phosphorylated protein level of mTOR, S6K and 4EBP1. Correspondingly, mTORC1 inhibitor rapamycin blocked the effect of BMP2 on NPC cell proliferation and invasion. In conclusion, our results suggest that BMP2 overexpression in NPC enhances proliferation, invasion and EMT of tumor cells through the mTORC1 signaling pathway.

Overexpression of HSD17B4 exerts tumor suppressive function in adrenocortical carcinoma and is not associated with hormone excess

Aim

Adrenocortical carcinoma (ACC) is characterized with excessive hormone production. We therefore investigated expression of hormone-related genes in ACC.

Results

We queried status of 14 key genes directly involved in adrenal hormone production and found HSD17B4 expression was upregulated in 39% of ACC cases on top of all queried genes. Overexpression of HSD17B4 was significantly associate with a normo-hormonal phenotype. Constitutive HSD17B4 expression was higher in ACC cell line NCI-H295R than in adrenocortical small cell carcinoma cell line SW13. NCI-H295R cells with HSD17B4-knockdown (KD) demonstrated significantly inhibited proliferation, increased apoptosis, and increased cell cycle arrest. Enrichment analysis for mRNA expression in ACC samples with or without HSD17B4 overexpression showed significant change in p53 pathway. Replenish of HSD17B4 in SW13 cells and knockdown of HSD17B4 in H295R cells confirmed alterations in MDM4, ATR, and IE24 with alterations more contrasting in H295R cells. HSD17B4-KD inhibited cell invasion, migration and anchorage independent growth of NCI-H295R cells, but not of SW13 cells.

Materials and Methods

Clinical and genetic data of ACC samples were reproduced from the ACC dataset of The Cancer Genome Atlas (TCGA) database using cBioPortal. Genes participating in adrenal hormone production were queried. Association between gene status and hormone release were studied and in vitro assays using RNA interference were carried out.

Conclusions

Overexpression of HSD17B4 exerted tumor suppressive function in adrenocortical carcinoma and was not related to hormone excess. Crosstalk between HSD17B4 and p53 warrants further investigation.

LCMR1 interacts with DEK to suppress apoptosis in lung cancer cells

To win the war against lung cancer, the molecular mechanisms underlying its oncogenesis and metastasis must be identified in order to develop novel diagnosis and treatment strategies. We previously identified a novel gene, namely lung cancer metastasis related protein 1 (LCMR1; GenBank accession no. AY148462), which was demonstrated to be overexpressed in non‑small‑cell lung cancer. LCMR1 expression was significantly associated with clinical stage. To further understand the mechanism of LCMR1 in lung cancer, the present study screened a cDNA library from the lung cancer cell line 95D for proteins interacting with LCMR1 by yeast two‑hybrid assay, and the protein DEK was identified. Co‑immunoprecipitation and glutathione S‑transferase pull‑down assays were performed to confirm the interaction between LCMR1 and DEK in vivo and in vitro. The results demonstrated that the interaction was mediated primarily by the N‑terminal region of DEK, suggesting that LCMR1 may be involved in the regulation of cell apoptosis. Using RNA interference, DEK and LCMR1 were demonstrated to cooperate in the inhibition of apoptosis in lung cancer cells, and this effect was associated with the induced myeloid leukemia protein cell differentiation protein 1 pathway. The present findings suggest that LCMR1 might serve as a potential molecular target for lung cancer therapy.

Knockdown of mediator subunit Med19 suppresses bladder cancer cell proliferation and migration by downregulating Wnt/β-catenin signalling pathway

Mediator complex subunit 19 (Med19), a RNA polymerase II‐embedded coactivator, is reported to be involved in bladder cancer (BCa) progression, but its functional contribution to this process is poorly understood. Here, we investigate the effects of Med19 on malignant behaviours of BCa, as well as to elucidate the possible mechanisms. Med19 expression in 15 BCa tissues was significantly higher than adjacent paired normal tissues using real‐time PCR and Western blot analysis. Immunohistochemical staining of 167 paraffin‐embedded BCa tissues was performed, and the results showed that high Med19 protein level was positively correlated with clinical stages and histopathological grade. Med19 was knocked down in BCa cells using short‐hairpin RNA. Functional assays showed that knocking‐down of Med19 can suppress cell proliferation and migration in T24, UM‐UC3 cells and 5637 in vitro, and inhibited BCa tumour growth in vivo. TOP/FOPflash reporter assay revealed that Med19 knockdown decreased the activity of Wnt/β‐catenin pathway, and the target genes of Wnt/β‐catenin pathway were down‐regulated, including Wnt2, β‐catenin, Cyclin‐D1 and MMP‐9. However, protein levels of Gsk3β and E‐cadherin were elevated. Our data suggest that Med19 expression correlates with aggressive characteristics of BCa and Med19 knockdown suppresses the proliferation and migration of BCa cells through down‐regulating the Wnt/β‐catenin pathway, thereby highlighting Med19 as a potential therapeutic target for BCa treatment.

Knockdown of Mediator Complex Subunit 19 Suppresses the Growth and Invasion of Prostate Cancer Cells

Prostate cancer (PCa) is one of the most common cancers in elderly men. Mediator Complex Subunit 19 (Med19) is overexpressed and plays promotional roles in many cancers. However, the roles of Med19 in PCa are still obscure. In this study, by using immunohistochemical staining, we found higher expression level of Med19 in PCa tissues than in adjacent benign prostate tissues. We then knocked down the Med19 expression in PCa cell lines LNCaP and PC3 by using lentivirus siRNA. Cell proliferation, anchor-independent growth, migration, and invasion were suppressed in Med19 knockdown PCa cells. In nude mice xenograft model, we found that Med19 knockdown PCa cells formed smaller tumors with lower proliferation index than did control cells. In the mechanism study, we found that Med19 could regulate genes involved in cell proliferation, cell cycle, and epithelial-mesenchymal transition, including P27, pAKT, pPI3K, IGF1R, E-Cadherin, N-Cadherin, Vimentin, ZEB2, Snail-1 and Snail-2. Targeting Med19 in PCa cells could inhibit the PCa growth and metastasis, and might be a therapeutic option for PCa in the future.

A large-scale RNAi screen identifies LCMR1 as a critical regulator of Tspan8-mediated melanoma invasion

Melanoma is the deadliest form of skin cancer owing to its proclivity to metastasise, and recently developed therapies have not yielded the expected results, because almost all patients relapse. Therefore, understanding the molecular mechanisms that underlie early invasion by melanoma cells is crucial to improving patient survival. We have previously shown that, whereas the Tetraspanin 8 protein (Tspan8) is undetectable in normal skin and benign lesions, its expression arises with the progression of melanoma and is sufficient to increase cell invasiveness. Therefore, to identify Tspan8 transcriptional regulators that could explain the onset of Tspan8 expression, thereby conferring an invasive phenotype, we performed an innovative RNA interference-based screen, which, for the first time, identified several Tspan8 repressors and activators, such as GSK3β, PTEN, IQGAP1, TPT1 and LCMR1. LCMR1 is a recently identified protein that is overexpressed in numerous carcinomas; its expression and role, however, had not previously been studied in melanoma. The present study identified Tspan8 as the first LCMR1 target that could explain its function in carcinogenesis. LCMR1 modulation was sufficient to positively regulate endogenous Tspan8 expression, with concomitant in vitro phenotypic changes such as loss of melanoma cell-matrix adherence and increase in invasion, and Tspan8 expression promoted tumourigenicity in vivo. Moreover, LCMR1 and Tspan8 overexpression were shown to correlate in melanoma lesions, and both proteins could be downregulated in vitro by vemurafenib. In conclusion, this study highlights the importance of Tspan8 and its regulators in the control of early melanoma invasion and suggests that they may be promising new therapeutic targets downstream of the RAF-MEK-ERK signalling pathway.

Bone morphogenetic protein-2 and tumor growth: Diverse effects and possibilities for therapy

Concern regarding safety with respect to the clinical use of human bone morphogenetic protein-2 (BMP-2) has become an increasingly controversial topic. The role of BMP-2 in carcinogenesis is of particular concern. Although there have been many studies of this topic, the results have been contradictory and confusing. We conducted a systematic review of articles that are relevant to the relationship or effect of BMP-2 on all types of tumors and a total of 97 articles were included. Studies reported in these articles were classified into three major types: "expression studies", "in vitro studies", and "in vivo studies". An obvious pattern was that those works that hypothesize an inhibitory effect for BMP-2 most often examined only the proliferative properties of the tumor cells. This subset of studies also contained an extraordinary number of contradictory findings which made drawing a reliable general conclusion impossible. In general, we support a pro-tumorigenesis role for BMP-2 based on the data from these in vitro cell studies and in vivo animal studies, however, more clinical studies should be carried out to help make a firm conclusion.

Effect of PI3K/Akt Signaling Pathway on the Process of Prostate Cancer Metastasis to Bone

We sought to study the effects of PI3K/Akt pathway and its downstream substrate NF-κB on prostate cancer bone metastatic process. Expression level of active p-Akt in PC3 cells was upregulated by transient expression with constitutively active plasmid CA-Akt or, alternatively, suppressed by dominant negative construct DN-Akt. NF-κB activity was determined by luciferase reporter assays. mRNA and protein expressions of receptor activator of NF-κB ligand (RANKL), parathyroid hormone-related protein (PTHrP), and bone morphogenetic protein 2 (BMP-2) were evaluated using RT-PCR and Western blotting. The effect of cross-talk between PC3 and SaOS2 cells on cell proliferation was analyzed using a co-culture system. Stimulation of p-Akt promoted NF-κB activity, and led to an increase in mRNA and protein expressions of RANKL, PTHrP, and BMP-2 in PC3 PCa cells through NF-κB. Co-culturing PC3 and SaOS2 cells significantly increased the expression of p-Akt and the activity of NF-κB, and promoted proliferation of both PC3 and SaOS2 cells. Increasing expression levels of p-Akt by transfection with CA-Akt led to further increase in cells proliferation, whereas NF-κB inhibitor PDTC partially blocked this effect. PI3K/Akt pathway stimulates the expressions of RANKL, PTHrP, and BMP-2 partly through NF-κB, suggesting its importance for bone metastasis of prostate carcinoma. Interaction of prostate cancer cells with bone cells has a stimulatory effect on cell proliferation.

The FOXD3/miR-214/MED19 axis suppresses tumour growth and metastasis in human colorectal cancer

Background:

MiR-214 is aberrantly regulated in several tumours, but its underlying mechanisms in colorectal cancer (CRC) metastasis remain largely unknown. This study aimed to demonstrate the function and potential mechanism of miR-214 in regulating invasion and metastasis of CRC.

Methods:

The transcription factor and targets of miR-214 were predicted by bioinformatics and validated using ChIP and dual-luciferase reporter assay. DNA methylation status was explored using bisulphite sequencing PCR. The in vitro and in vivo function of miR-214 in CRC was evaluated using MTT, plate colony formation, Matrigel invasion and animal models. Real-time PCR or western blotting was performed to detect FOXD3, miR-214 and MED19 expressions in CRC cells and clinical specimens.

Results:

MiR-214 was downregulated in CRC and was significantly correlated with lymphatic metastasis. Downregulation of miR-214 might due to promoter hypermethylation in CRC. FOXD3 was validated as a transcription factor of miR-214 by ChIP assay. Dual-luciferase assay identified MED19 as a target of miR-214 in CRC. In vitro and in vivo experiments showed that miR-214 mediated the inhibiting effect of FOXD3 on proliferation, invasion and metastasis by targeting MED19. Spearman's correlation analysis showed a positive correlation between FOXD3 and miR-214, and negative correlations between FOXD3 and MED19, miR-214 and MED19 in CRC cells and clinical specimens.

Conclusions:

FOXD3/miR-214/MED19 axis is important for the regulation of growth, invasion and metastasis of CRC. Targeting the miR-214-mediated axis might be helpful for the treatment of CRC.

Genetic Alteration in Phosphofructokinase Family Promotes Growth of Muscle-Invasive Bladder Cancer

Aims

Metabolic alterations in cancer, including bladder cancer, have been addressed in recent years. We aimed to study the role of phosphofructokinase (PFK) in muscle-invasive bladder cancer (MIBC).

Method

By in silico analysis of the bladder cancer data from the Cancer Genome Atlas (TCGA) database using the cBioPortal platform, we studied genetic alteration of genes within the PFK family (PFKL, PFKM, PFKP, PFKFB1, PFKFB2, PFKFB3, and PFKFB4). In vitro studies were carried out using the PFK inhibitor 2,5-anhydro-D-glucitol-6-phosphate.

Results

Genetic alterations of PFK family genes were observed in ~44% of MIBC cases in TCGA. The main alterations were amplification and upregulation. Patients with altered PFK gene status were more likely to have a history of noninvasive bladder cancer. Altered PFK status was not associated with survival or disease relapse. Use of the PFK inhibitor significantly decreased the level of glycolysis and inhibited the growth and invasion of bladder cancer cells.

Conclusions

PFKs were critical genes in charge of glycolysis and were upregulated in bladder cancer. Targeting this pathway could inhibit cell growth in bladder cancer.

Knockdown of Med19 suppresses proliferation and enhances chemo-sensitivity to cisplatin in non-small cell lung cancer cells

Mediator 19 (Med19) is a component of the mediator complex which is a coactivator for DNA-binding factors that activate transcription via RNA polymerase II. Accumulating evidence has shown that Med19 plays important roles in cancer cell proliferation and tumorigenesis. The involvement of Med19 in sensitivity to the chemotherapeutic agent cisplatin was here investigated. We employed RNA interference to reduce Med19 expression in human non-small cell lung cancer (NSCLC) cell lines and analyzed their phenotypic changes. The results showed that after Med19 siRNA transfection, expression of Med19 mRNA and protein was dramatically reduced (p<0.05). Meanwhile, impaired growth potential, arrested cell cycle at G0/G1 phase and enhanced sensitivity to cisplatin were exhibited. Apoptosis and caspase-3 activity were increased when cells were exposed to Med19 siRNA and/or cisplatin. The present findings suggest that Med19 facilitates tumorigenic properties of NSCLC cells and knockdown of Med19 may be a rational therapeutic tool for lung cancer cisplatin sensitization.

The Brakeless co-regulator can directly activate and repress transcription in early Drosophila embryos

The Brakeless protein performs many important functions during Drosophila development, but how it controls gene expression is poorly understood. We previously showed that Brakeless can function as a transcriptional co-repressor. In this work, we perform transcriptional profiling of brakeless mutant embryos. Unexpectedly, the majority of affected genes are down-regulated in brakeless mutants. We demonstrate that genomic regions in close proximity to some of these genes are occupied by Brakeless, that over-expression of Brakeless causes a reciprocal effect on expression of these genes, and that Brakeless remains an activator of the genes upon fusion to an activation domain. Together, our results show that Brakeless can both repress and activate gene expression. A yeast two-hybrid screen identified the Mediator complex subunit Med19 as interacting with an evolutionarily conserved part of Brakeless. Both down- and up-regulated Brakeless target genes are also affected in Med19-depleted embryos, but only down-regulated targets are influenced in embryos depleted of both Brakeless and Med19. Our data provide support for a Brakeless activator function that regulates transcription by interacting with Med19. We conclude that the transcriptional co-regulator Brakeless can either activate or repress transcription depending on context.

The BMP signaling pathway leads to enhanced proliferation in serous ovarian cancer-A potential therapeutic target

Members of the transforming growth factor-β (TGF-β) superfamily transduce signals via SMAD proteins. SMAD2 and SMAD3 mediate TGF-β signaling, whereas SMAD1, SMAD5, and SMAD8/9 transduce bone morphogenetic protein (BMP) signals. We would like to identify the function of BMP/SMAD5 signaling in serous ovarian cancer. The protein levels of total SMAD5 and phosphorylated SMAD5 (pSMAD5) were examined by immunohistochemical analysis using clinical serous ovarian cancer samples. Following treatment with either recombinant BMP2 (rBMP2) or Dorsomorphin (DM), western blotting was performed to observe pSMAD5 protein in the cytoplasm and the nucleus, separately. Cell proliferation was detected in SMAD5 knockdown serous ovarian cancer cell lines cultured with DM or rBMP2. The impact of DM or rBMP2 on tumor growth was observed in a mouse model of serous ovarian cancer. An inverse correlation was observed between pSMAD5 levels in the nucleus and the prognosis of patients with serous ovarian cancer. The treatment of SK-OV-3 with rBMP2 stimulated pSMAD5 translocation from the cytoplasm to the nucleus, and the addition of DM inhibited this effect. The proliferation of ovarian cancer cell lines was enhanced by BMP2 and suppressed by DM via SMAD5 in vitro. In vitro and in vivo experiments clearly demonstrated BMP2-stimulated proliferation of serous ovarian cancer and inhibition of this effect by DM. Our data suggests that BMP/SMAD5 signaling plays an important role and, therefore, becomes a potential therapeutic target in serous ovarian cancer. © 2015 Wiley Periodicals, Inc.

Loss of MLH1 confers resistance to PI3Kβ inhibitors in renal clear cell carcinoma with SETD2 mutation

Renal clear cell carcinoma (ccRCC) is characterized by frequent mutation in SETD2, which has recently been shown to regulate mismatch repair (MMR). We aim to investigate the association between MMR machinery genes and SETD2 mutation in ccRCC. We exploited the Genomics of Drug Sensitivity in Cancer (GDSC) database to identify selective inhibitors for SETD2 mutant ccRCC cells. We also exploited the Cancer Genome Atlas (TCGA) database to study the association between SETD2 status and MMR-related genes. In vitro studies were performed to validate the in silico findings. Reproduction of the GDSC database revealed four compounds with significant selectivity for SETD2 mutant ccRCC cells, amongst which two compounds targeted PI3Kβ. Phosphorylation of AKT at both S473 and T308 was decreased following PI3Kβ inhibitor treatment in SETD2 mutant ccRCC cells, whereas the basal pAKT level was not changed between mutant and wild-type SETD2. Both decreased MLH1 and increased AKT levels induced lower PMS2, indicating that MMR was mediated by SETD2 via both AKT and MLH1 in ccRCC. Analysis of the TCGA database further revealed high tendency of homozygous co-deletion of SETD2 and MLH1. In the absence of MLH1, suppression of pAKT by PI3Kβ inhibitor was mitigated and inhibition in cell proliferation, invasiveness, migratory ability and tumourigenesis was partially restored. Besides the reported H3K36-trimethylation pathway, we found that SETD2 mutation also mediated MMR via AKT-induced PMS2 decrease and co-loss of MLH1 loss in ccRCC.

Inhibition of mTOR pathway attenuates migration and invasion of gallbladder cancer via EMT inhibition

Gallbladder cancer (GBC) is an aggressive disease in which epithelial-mesenchymal transition (EMT) plays a critical role. Whether inhibition of mTOR effects via EMT reversal in GBC remains unclear. Using genetic and pharmacologic inhibitions of mTOR, we investigated the changes of EMT levels in GBC cells. Expressions of EMT related genes were also studied. Migration and invasion assays were carried out and in vivo tumour metastasis mouse models were established. Circulating tumour DNA was quantified. We used EMT index (ratio of Vimentin/Ecadherin expression) to profile EMT levels. We found that inhibition of mTOR using shRNAs and rapamycin inhibited EMT in GBC-SD gallbladder cancer cells. Inhibition of mTOR inhibited EMT in GBC-SD cells in TGF-β-dependent manner, which was contributed majorly by mTORC2 inhibition. Rapamycin decreased invasiveness and migration of GBC-SD cells in vitro and in vivo. We have in the current study shown that rapamycin diminishes the ability of invasion and migration of GBC via inhibition of TGF-β-dependent EMT. Our findings contribute to the understanding of the carcinogenesis of GBC.

Involvement of Mediator complex in malignancy

Mediator complex (MED) is an evolutionarily conserved multiprotein, fundamental for growth and survival of all cells. In eukaryotes, the mRNA transcription is dependent on RNA polymerase II that is associated to various molecules like general transcription factors, MED subunits and chromatin regulators. To date, transcriptional machinery dysfunction has been shown to elicit broad effects on cell proliferation, development, differentiation, and pathologic disease induction, including cancer. Indeed, in malignant cells, the improper activation of specific genes is usually ascribed to aberrant transcription machinery. Here, we focus our attention on the correlation of MED subunits with carcinogenesis. To date, many subunits are mutated or display altered expression in human cancers. Particularly, the role of MED1, MED28, MED12, CDK8 and Cyclin C in cancer is well documented, although several studies have recently reported a possible association of other subunits with malignancy. Definitely, a major comprehension of the involvement of the whole complex in cancer may lead to the identification of MED subunits as novel diagnostic/prognostic tumour markers to be used in combination with imaging technique in clinical oncology, and to develop novel anti-cancer targets for molecular-targeted therapy.

Inhibition of mTOR and HIF pathways diminishes chondro-osteogenesis and cell proliferation in chondroblastoma

Chondroblastoma (CBL) is a benign bone tumor occurring mostly in teenagers. Despite this, CBL can recur and metastasize after curettage, which may impede normal epiphysis. In search of a novel targeted therapy for CBL, we aimed at BMP-2, a factor critical for chondro-osteogenesis and chondrocyte proliferation. Two pathways upstream of BMP-2, the mTOR and HIF, were targeted with rapamycin (Rapa) and FM19G11 (FM), respectively. Using immunohistochemistry, we found BMP-2 was highly expressed in CBL tissues. CBL cells explanted and confirmed with higher BMP-2 level than normal cartilage. Protumorigenic effect of Rapa and FM on CBL cells were transduced via BMP-2. Combination of Rapa and FM conferred stronger inhibition of cell proliferation than either monotherapy and inhibited levels of chondro-osteogenic markers (Sox9, aggrecan, and type II collagen). To minimize the adverse effect of Rapa, we performed screening in essential amino acids and found leucine deprivation-sensitized CBL cells to Rapa. Combination treatment of low dose Rapa, FM, and leucine deprivation conferred compatible inhibitory effects on CBL cell proliferation, chondro-osteogenic potential, and tumorigenic capacity. We conclude that targeting BMP-2 using mTOR/HIF inhibition could potently curb the disease. Addition of low-leucine diet could lower the dose of rapamycin in chase for less toxicity.