RBP2 induces stem-like cancer cells by promoting EMT and is a prognostic marker for renal cell carcinoma

Phospholipase C Beta 2 as a Key Regulator of Tumor Progression and Epithelial-Mesenchymal Transition via PI3K/AKT Signaling in Renal Cell Carcinoma

Background: Renal cell carcinoma (RCC) represents the most common form of invasive kidney cancer in adults. Among the components critical to cellular regulation is Phospholipase C Beta 2 (PLCB2), a member of the phospholipase C enzyme family. This enzyme plays a vital role in managing key cellular functions such as growth, differentiation, migration, and survival. Despite its significant importance, the specific expression patterns and molecular mechanisms of PLCB2 in the progression of RCC are not well understood. Methods: This investigation employed a combination of bioinformatics analyses, scRNA-seq, functional assays, transcriptome sequencing, real-time quantitative PCR (RT-PCR), immunofluorescence, rescue experiments, and Western blotting to explore the regulatory function of PLCB2 in driving the epithelial-mesenchymal transition (EMT) in RCC through the PI3K/AKT signaling pathway. Results:PLCB2 expression is significantly elevated in RCC samples, and this increase is inversely correlated with patient prognosis. The knockdown of PLCB2 in RCC cell lines leads to a marked reduction in cell proliferation, invasion, migration, and EMT. Transcriptome sequencing further revealed that PLCB2 is significantly associated with the PI3K/AKT pathway. Notably, the PI3K activator 740Y-P was able to reverse the reductions in migration, invasion, and EMT caused by the PLCB2 knockdown. Conclusions: Our findings underscore the pivotal role of PLCB2 in regulating RCC invasion and metastasis by modulating the EMT via the PI3K/AKT signaling pathway. This highlights PLCB2 not only as a key prognostic biomarker, but also as a promising therapeutic target in the treatment of advanced-stage RCC, offering new avenues for more effective interventions.

Multi-bioinformatics revealed potential biomarkers and repurposed drugs for gastric adenocarcinoma-related gastric intestinal metaplasia

Biomarkers associated with the progression from gastric intestinal metaplasia (GIM) to gastric adenocarcinoma (GA), i.e., GA-related GIM, could provide valuable insights into identifying patients with increased risk for GA. The aim of this study was to utilize multi-bioinformatics to reveal potential biomarkers for the GA-related GIM and predict potential drug repurposing for GA prevention in patients. The multi-bioinformatics included gene expression matrix (GEM) by microarray gene expression (MGE), ScType (a fully automated and ultra-fast cell-type identification based solely on a given scRNA-seq data), Ingenuity Pathway Analysis, PageRank centrality, GO and MSigDB enrichments, Cytoscape, Human Protein Atlas and molecular docking analysis in combination with immunohistochemistry. To identify GA-related GIM, paired surgical biopsies were collected from 16 GIM-GA patients who underwent gastrectomy, yielding 64 samples (4 biopsies per stomach x 16 patients) for MGE. Co-analysis was performed by including scRNAseq and immunohistochemistry datasets of endoscopic biopsies of 37 patients. The results of the present study showed potential biomarkers for GA-related GIM, including GEM of individual patients, individual genes (such as RBP2 and CD44), signaling pathways, network of molecules, and network of signaling pathways with key topological nodes. Accordingly, potential treatment targets with repurposed drugs were identified including epidermal growth factor receptor, proto-oncogene tyrosine-protein kinase Src, paxillin, transcription factor Jun, breast cancer type 1 susceptibility protein, cellular tumor antigen p53, mouse double minute 2, and CD44.

Sex-specific molecular signature of mouse podocytes in homeostasis and in response to pharmacological challenge with rapamycin

BACKGROUND

Sex differences exist in the prevalence and progression of major glomerular diseases. Podocytes are the essential cell-type in the kidney which maintain the physiological blood-urine barrier, and pathological changes in podocyte homeostasis are critical accelerators of impairment of kidney function. However, sex-specific molecular signatures of podocytes under physiological and stress conditions remain unknown. This work aimed at identifying sexual dimorphic molecular signatures of podocytes under physiological condition and pharmacologically challenged homeostasis with mechanistic target of rapamycin (mTOR) inhibition. mTOR is a crucial regulator involved in a variety of physiological and pathological stress responses in the kidney and inhibition of this pathway may therefore serve as a general stress challenger to get fundamental insights into sex differences in podocytes.

METHODS

The genomic ROSAmT/mG-NPHS2 Cre mouse model was used which allows obtaining highly pure podocyte fractions for cell-specific molecular analyses, and vehicle or pharmacologic treatment with the mTOR inhibitor rapamycin was performed for 3 weeks. Subsequently, deep RNA sequencing and proteomics were performed of the isolated podocytes to identify intrinsic sex differences. Studies were supplemented with metabolomics from kidney cortex tissues.

RESULTS

Although kidney function and morphology remained normal in all experimental groups, RNA sequencing, proteomics and metabolomics revealed strong intrinsic sex differences in the expression levels of mitochondrial, translation and structural transcripts, protein abundances and regulation of metabolic pathways. Interestingly, rapamycin abolished prominent sex-specific clustering of podocyte gene expression and induced major changes only in male transcriptome. Several sex-biased transcription factors could be identified as possible upstream regulators of these sexually dimorphic responses. Concordant to transcriptomics, metabolomic changes were more prominent in males. Remarkably, high number of previously reported kidney disease genes showed intrinsic sexual dimorphism and/or different response patterns towards mTOR inhibition.

CONCLUSIONS

Our results highlight remarkable intrinsic sex-differences and sex-specific response patterns towards pharmacological challenged podocyte homeostasis which might fundamentally contribute to sex differences in kidney disease susceptibilities and progression. This work provides rationale and an in-depth database for novel targets to be tested in specific kidney disease models to advance with sex-specific treatment strategies.

NAT1 inhibits liver metastasis of colorectal cancer by regulating EMT and glycolysis

Metastasis is the primary cause of cancer-related deaths, and colorectal cancer (CRC) liver metastasis is a major poor prognostic factor in CRC. NAT1 (N-acetyltransferase 1) plays a crucial role in the invasive and metastatic processes of colorectal cancer. The role and molecular mechanism of NAT1 on tumor cells were verified by establishing a cell model of overexpression and knockdown of NAT1, and further verified by establishing a liver metastasis model of colorectal cancer for animal experiments. In vivo and in vitro experiments have demonstrated that overexpression of NAT1 reduces the ability of metastasis and invasion of colorectal cancer cells. NAT1 overexpression inhibits the PI3K/AKT/mTOR signaling pathway, thereby suppressing the EMT (epithelial-mesenchymal transition) process and glycolytic ability of tumor cells. Additionally, decreased glycolytic ability results in reduced VEGF (Vascular endothelial growth factor) expression in colorectal cancer cells. The decreased VEGF expression leads to decreased angiogenesis and vascular permeability in liver metastases, ultimately reducing the occurrence of liver metastasis. Our findings highlight that overexpression of NAT1 significantly inhibits the PI3K/AKT/mTOR signaling pathway, thereby suppressing EMT, glycolytic ability, and VEGF expression in colorectal cancer cells, collectively preventing the development of liver metastasis.

Exploiting transcription factors to target EMT and cancer stem cells for tumor modulation and therapy

Transcription factors (TFs) are essential in controlling gene regulatory networks that determine cellular fate during embryogenesis and tumor development. TFs are the major players in promoting cancer stemness by regulating the function of cancer stem cells (CSCs). Understanding how TFs interact with their downstream targets for determining cell fate during embryogenesis and tumor development is a critical area of research. CSCs are increasingly recognized for their significance in tumorigenesis and patient prognosis, as they play a significant role in cancer initiation, progression, metastasis, and treatment resistance. However, traditional therapies have limited effectiveness in eliminating this subset of cells, allowing CSCs to persist and potentially form secondary tumors. Recent studies have revealed that cancer cells and tumors with CSC-like features also exhibit genes related to the epithelial-to-mesenchymal transition (EMT). EMT-associated transcription factors (EMT-TFs) like TWIST and Snail/Slug can upregulate EMT-related genes and reprogram cancer cells into a stem-like phenotype. Importantly, the regulation of EMT-TFs, particularly through post-translational modifications (PTMs), plays a significant role in cancer metastasis and the acquisition of stem cell-like features. PTMs, including phosphorylation, ubiquitination, and SUMOylation, can alter the stability, localization, and activity of EMT-TFs, thereby modulating their ability to drive EMT and stemness properties in cancer cells. Although targeting EMT-TFs holds potential in tackling CSCs, current pharmacological approaches to do so directly are unavailable. Therefore, this review aims to explore the role of EMT- and CSC-TFs, their connection and impact in cellular development and cancer, emphasizing the potential of TF networks as targets for therapeutic intervention.

KDM5A noncanonically binds antagonists MLL1/2 to mediate gene regulation and promotes epithelial to mesenchymal transition

Differential expression of genes involved in certain processes is a collaborative outcome of crosstalk between signalling molecules and epigenetic modifiers. In response to environmental stimulus, interplay between transcription factors and epigenetic modifiers together dictates the regulation of genes. MLLs and KDM5A are functionally antagonistic proteins, as one acts as a writer and the other erases the active chromatin mark, i.e., H3K4me3. KDM5A influences the process of EMT by binding to both epithelial and mesenchymal gene promoters. Through this work, we show that when bound to E-cadherin promoter, KDM5A acts as a classical repressor by demethylating H3K4me3, but on mesenchymal markers, it acts as a transcriptional activator by inhibiting the activity of HDACs and increasing H3K18ac. Further, through our chromatin immunoprecipitation experiments, we observed a co-occupancy of KDM5A with MLLs, we tested whether KDM5A might physically interact with MLLs and WDR5, and here we provide experimental evidence that KDM5A indeed interacts with MLLs and WDR5.

PCMT1 regulates the migration, invasion, and apoptosis of prostate cancer through modulating the PI3K/AKT/GSK-3β pathway

Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) is a repair enzyme that catalyzes the conversion of isomerized aspartic acid (iso-Asp) residues into their normal structure, thereby restoring the configuration and function of proteins. Studies have shown that PCMT1 is overexpressed in several tumors and affects patients' prognosis. However, there are few reports on the role of PCMT1 in prostate cancer (PCa). In the present research, with the assistance of The Cancer Genome Atlas Program (TCGA) database, we found that PCMT1 was overexpressed in PCa tissues. The results of quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blot and immunohistochemistry staining also showed that PCMT1 expression was significantly increased in PCa tissues and cell lines. In PCa clinical samples, PCMT1 expression was closely related to Gleason score, clinical stage, lymph node metastasis and bone metastasis. The experiments of overexpression and knockdown of PCMT1 in vitro or in vivo showed that PCMT1 can significantly promote the proliferation, migration and invasion of PCa cells, inhibit cell apoptosis, and promote the growth of PCa. We furthermore confirmed that PCMT1 regulated the migration, invasion and apoptosis of PCa cells by modulating the phosphatidylinositol 3-kinase/AKT kinase/glycogen-synthase kinase-3β (PI3K/AKT/GSK-3β) signaling pathway. Collectively, PCMT1 plays a cancer-facilitative role in PCa by promoting the proliferation, migration and invasion of PCa cells, and inhibiting apoptosis. Therefore, PCMT1 is considered to represent a novel target for treating PCa.

Cancer plasticity: Investigating the causes for this agility

Cancer is not a hard-wired phenomenon but an evolutionary disease. From the onset of carcinogenesis, cancer cells continuously adapt and evolve to satiate their ever-growing proliferation demands. This results in the formation of multiple subtypes of cancer cells with different phenotypes, cellular compositions, and consequently displaying varying degrees of tumorigenic identity and function. This phenomenon is referred to as cancer plasticity, during which the cancer cells exist in a plethora of cellular states having distinct phenotypes. With the advent of modern technologies equipped with enhanced resolution and depth, for example, single-cell RNA-sequencing and advanced computational tools, unbiased cancer profiling at a single-cell resolution are leading the way in understanding cancer cell rewiring both spatially and temporally. In this review, the processes and mechanisms that give rise to cancer plasticity include both intrinsic genetic factors such as epigenetic changes, differential expression due to changes in DNA, RNA, or protein content within the cancer cell, as well as extrinsic environmental factors such as tissue perfusion, extracellular milieu are detailed and their influence on key cancer plasticity hallmarks such as epithelial-mesenchymal transition (EMT) and cancer cell stemness (CSCs) are discussed. Due to therapy evasion and drug resistance, tumor heterogeneity caused by cancer plasticity has major therapeutic ramifications. Hence, it is crucial to comprehend all the cellular and molecular mechanisms that control cellular plasticity. How this process evades therapy, and the therapeutic avenue of targeting cancer plasticity must be diligently investigated.

RBBP4 plays a vital role in the malignant progression of triple-negative breast cancer by regulating epithelial-mesenchymal transition

BACKGROUND

Mounting findings have revealed the increasingly appreciated functional importance of Retinoblastoma binding protein (RBBP) family members in tumorigenesis. However, the biological function of RBBP4 in breast cancer, especially in the most malignant and aggressive subtype, i.e., triple-negative breast cancer (TNBC), remains to be elucidated.

OBJECTIVE

The present study was aimed at elucidating the role of RBBP4 in TNBC pathogenesis.

METHODS

The expression of RBBP4 in TNBC tissues and cell lines was examined and its oncogenic-related functions were verified by performing a series of in vitro and in vivo experiments.

RESULTS

At the cellular and tissue level, a marked increase in the RBBP4 expression was observed. Functionally, RBBP4 knockdown dramatically inhibited the proliferation, invasion, and migration of TNBC cells in vitro. Further, mechanistically, RBBP4 downregulation regulated the inactivation of epithelial-mesenchymal transition (EMT) of TNBC cells. In vivo xenograft model in nude mice also validated these results.

CONCLUSION

Collectively, our results showed that the inhibition of RBBP4 suppresses the malignant progression of TNBC cells by regulating EMT. Thus, RBBP4 could serve as a novel biomarker and target for TNBC diagnosis and treatment.

Cancer-associated fibroblasts in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of mortality among cancers. Many aspects of this cancer are under investigation to find established markers of diagnosis, prognosis, and also potential drug targets. In this review article, we are going to discuss the possible solution to all these aims by investigating the literature about cancer-associated fibroblasts (CAFs) involved in CRC. Moreover, we are going to review their interaction with the tumor microenvironment (TME) and vitamin D and their role in tumorigenesis and metastasis. Moreover, we are going to expand more on some markers produced by them or related to them including FAP, a-SMA, CXCL12, TGF- β, POSTN, and β1-Integrin. Some signaling pathways related to CAFs are as follows: FAK, AKT, activin A, and YAP/TAZ. Some genes related to the CAFs which are found to be possible therapeutic targets include COL3A1, JAM3, AEBP1 and, CAF-derived TGFB3, WNT2, and WNT54.

Development and validation of a robust epithelial-mesenchymal transition (EMT)-related prognostic signature for hepatocellular carcinoma

OBJECTIVE

Epithelial-to-mesenchymal transition (EMT) is an essential biological process of cancer progression associated with increased metastatic potential and initiation. Herein, we aimed to develop and validate a robust EMT-related prognostic signature that could predict the prognosis of patients with hepatocellular carcinoma (HCC).

METHODS

Messenger RNA expression matrix and clinicopathological data were retrieved from The Cancer Genome Atlas (TCGA) and identified differentially expressed genes (DEGs) between HCC tissues and adjacent non-tumor samples. Univariate Cox regression analysis, least absolute shrinkage and selection operator (LASSO) Cox regression and multivariate Cox regression analysis were performed to establish a prognosis signature. Kaplan-Meier survival curve, time-dependent receiver operating characteristic (ROC), multivariate Cox regression analysis, nomogram, C-index, and decision curve analysis (DCA) were performed to investigate the prognostic performance of the signature. The prognostic performance of the new signature was further validated in an independent external cohort. A support vector machine (SVM) approach was performed to evaluate the diagnostic value of the identified genes.

RESULTS

A seven-gene signature was formulated to classify patients into high-risk and low-risk groups with discrepant overall survival (OS) in two cohorts (all P < 0.0001), and the former illustrated shorter survival time than the latter even stratified by various groups. The new signature has presented an excellent performance for predicting survival prognosis. Multivariate analysis showed that the signature was an independent risk factor for HCC. The SVM classifier based on the seven genes presented an excellent diagnostic power in differentiating early HCC and normal tissues. Gene Set Enrichment Analyses (GSEA) demonstrated multiple biological processes and pathways to provide novel insights into the development of HCC.

CONCLUSION

We established and validated a prognostic signature based on EMT-related genes with good predictive value for HCC survival. The diagnostic performance of the signature had been demonstrated to accurately distinguish early HCC from control individuals.

A stemness-based eleven-gene signature correlates with the clinical outcome of hepatocellular carcinoma

Background

Cumulative evidences have been implicated cancer stem cells in the tumor environment of hepatocellular carcinoma (HCC) cells, whereas the biological functions and prognostic significance of stemness related genes (SRGs) in HCC is still unclear.

Methods

Molecular subtypes were identified by cumulative distribution function (CDF) clustering on 207 prognostic SRGs. The overall survival (OS) predictive gene signature was developed, internally and externally validated based on HCC datasets including The Cancer Genome Atlas (TCGA), GEO and ICGC datasets. Hub genes were identified in molecular subtypes by protein-protein interaction (PPI) network analysis, and then enrolled for determination of prognostic genes. Univariate, LASSO and multivariate Cox regression analyses were performed to assess prognostic genes and construct the prognostic gene signature. Time-dependent receiver operating characteristic (ROC) curve, Kaplan-Meier curve and nomogram were used to assess the performance of the gene signature.

Results

We identified four molecular subtypes, among which the C2 subtype showed the highest SRGs expression levels and proportions of immune cells, whereas the worst OS; the C1 subtype showed the lowest SRGs expression levels and was associated with most favorable OS. Next, we identified 11 prognostic genes (CDX2, PON1, ADH4, RBP2, LCAT, GAL, LPA, CYP19A1, GAST, SST and UGT1A8) and then constructed a prognostic 11-gene module and validated its robustness in all three datasets. Moreover, by univariate and multivariate Cox regression, we confirmed the independent prognostic ability of the 11-gene module for patients with HCC. In addition, calibration analysis plots indicated the excellent predictive performance of the prognostic nomogram constructed based on the 11-gene signature.

Conclusions

Findings in the present study shed new light on the role of stemness related genes within HCC, and the established 11-SRG signature can be utilized as a novel prognostic marker for survival prognostication in patients with HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08351-0.

Alterations of epigenetic regulators and P53 mutations in murine mesenchymal stem cell cultures: A possible mechanism of spontaneous transformation

BACKGROUND

Recent studies demonstrated the involvement of mesenchymal stem/stromal cells (MSCs) in carcinogenesis, but the molecular mechanism behind this transformation is still obscured.

OBJECTIVE

To screen both the expression levels of polycomb and trithorax epigenetic regulators and TrP53 mutations in early and late MSC culture passages in an attempt to decipher the mechanism of spontaneous transformation.

METHODS

The study was conducted on early and late passages of MSC culture model from C57BL/6J mice. The expression profile of 84 epigenetic regulators was examined using RT2 profiler PCR array. TrP53 mutations in the DNA binding domain was screened. Codons, amino acids positions and the corresponding human variants were detected in P53 sequences.

RESULTS

Sixty-two epigenetic regulators were dysregulated. Abnormalities were detected starting the third passage. Nine regulators were dysregulated in all passages. (C>G) substitution P53 mutation was detected in passage 3 resulting in Ser152Arg substitution. Passages 6, 9, 12 and the last passage showed T>C substitution resulting in Cys235Arg substitution. The last passage had T deletion and A insertion resulting in frame shift mutations changing the p.Phe286Ser and p.Asn103Lys respectively.

CONCLUSION

In vitro expanded MSCs undergo transformation through alteration of epigenetic regulators which results in genomic instability and frequent P53 mutations.

Three-Dimensional Imaging in Stem Cell-Based Researches

Stem cells have an important role in regenerative therapies, developmental biology studies and drug screening. Basic and translational research in stem cell technology needs more detailed imaging techniques. The possibility of cell-based therapeutic strategies has been validated in the stem cell field over recent years, a more detailed characterization of the properties of stem cells is needed for connectomics of large assemblies and structural analyses of these cells. The aim of stem cell imaging is the characterization of differentiation state, cellular function, purity and cell location. Recent progress in stem cell imaging field has included ultrasound-based technique to study living stem cells and florescence microscopy-based technique to investigate stem cell three-dimensional (3D) structures. Here, we summarized the fundamental characteristics of stem cells via 3D imaging methods and also discussed the emerging literatures on 3D imaging in stem cell research and the applications of both classical 2D imaging techniques and 3D methods on stem cells biology.

miR-181d/RBP2/NF-κB p65 Feedback Regulation Promotes Chronic Myeloid Leukemia Blast Crisis

Background

Chronic myeloid leukemia (CML) is a malignant clonal proliferative disease. Once it progresses into the phase of blast crisis (CML-BP), the curative effect is poor, and the fatality rate is extremely high. Therefore, it is urgent to explore the molecular mechanisms of blast crisis and identify new therapeutic targets.

Methods

The expression levels of miR-181d, RBP2 and NF-κB p65 were assessed in 42 newly diagnosed CML-CP patients and 15 CML-BP patients. Quantitative real-time PCR, Western blots, and cell proliferation assay were used to characterize the changes induced by overexpression or inhibition of miR-181d, RBP2 or p65. Luciferase reporter assay and ChIP assay was conducted to establish functional association between miR-181d, RBP2 and p65. Inhibition of miR-181d expression and its consequences in tumor growth was demonstrated in vivo models.

Results

We found that miR-181d was overexpressed in CML-BP, which promoted leukemia cell proliferation. Histone demethylase RBP2 was identified as a direct target of miR-181d which downregulated RBP2 expression. Moreover, RBP2 inhibited transcriptional expression of NF-κB subunit, p65 by binding to its promoter and demethylating the tri/dimethylated H3K4 region in the p65 promoter locus. In turn, p65 directly bound to miR-181d promoter and upregulated its expression. Therefore, RBP2 inhibition resulting from miR-181d overexpression led to p65 upregulation which further forwarded miR-181d expression. This miR-181d/RBP2/p65 feedback regulation caused sustained NF-κB activation, which contributed to the development of CML-BP.

Conclusions

Taken together, the miR-181d/RBP2/p65 feedback regulation promoted CML-BP and miR-181d may serve as a potential therapeutic target of CML-BP.

The emerging role of KDM5A in human cancer

Histone methylation is a key posttranslational modification of chromatin, and its dysregulation affects a wide array of nuclear activities including the maintenance of genome integrity, transcriptional regulation, and epigenetic inheritance. Variations in the pattern of histone methylation influence both physiological and pathological events. Lysine-specific demethylase 5A (KDM5A, also known as JARID1A or RBP2) is a KDM5 Jumonji histone demethylase subfamily member that erases di- and tri-methyl groups from lysine 4 of histone H3. Emerging studies indicate that KDM5A is responsible for driving multiple human diseases, particularly cancers. In this review, we summarize the roles of KDM5A in human cancers, survey the field of KDM5A inhibitors including their anticancer activity and modes of action, and the current challenges and potential opportunities of this field.

Histone demethylase KDM5A promotes tumorigenesis of osteosarcoma tumor

Osteosarcoma is a primary bone malignancy with a high rate of recurrence and poorer prognosis. Therefore, it is of vital importance to explore novel prognostic molecular biomarkers and targets for more effective therapeutic approaches. Previous studies showed that histone demethylase KDM5A can increase the proliferation and metastasis of several cancers. However, the function of KDM5A in the carcinogenesis of osteosarcoma is not clear. In the current study, KDM5A was highly expressed in osteosarcoma than adjacent normal tissue. Knockdown of KDM5A suppressed osteosarcoma cell proliferation and induced apoptosis. Moreover, knockdown of KDM5A could increase the expression level of P27 (cell-cycle inhibitor) and decrease the expression of Cyclin D1. Furthermore, after knockout of KDM5A in osteosarcoma cells by CRISPR/Cas9 system, the tumor size and growth speed were inhibited in tumor-bearing nude mice. RNA-Seq of KDM5A-KO cells indicated that interferon, epithelial–mesenchymal transition (EMT), IL6/JAK/STAT3, and TNF-α/NF-κB pathway were likely involved in the regulation of osteosarcoma cell viability. Taken together, our research established a role of KDM5A in osteosarcoma tumorigenesis and progression.

Molecular mechanisms of KDM5A in cellular functions: Facets during development and disease

Gene expression is influenced at many layers by a fine-tuned crosstalk between multiple extrinsic signalling pathways and intrinsic regulatory molecules that respond to environmental stimuli. Epigenetic modifiers like DNA methyltransferases, histone modifying enzymes and chromatin remodellers are reported to act as triggering factors in many scenarios by exhibiting their control over most of the cellular processes. These epigenetic players can either directly regulate gene expression or interact with some effector molecules that harmonize the expression of downstream genes. One such epigenetic regulator which exhibits multifaceted regulation over gene expression is KDM5A. It is classically a transcriptional repressor acting as H3K4me3 demethylase, but also is reported to act as an activator in many contexts either by loss of activity due to inhibition manifested by other interacting proteins or by downregulating the negative players of a given physiological process thereby escalating the framework. Through this review, we draw attention to the remarkable modes of functioning laid by KDM5A on transcriptional and translational processes, affecting gene expression during differentiation and development and finally summing up on role in disease causation (Fig. 1). We also shed light on different orthologs of KDM5A and their organism specific roles, along with comparison of the sequence similarity to extrapolate some unanswered questions about this protein.

Novel molecular signatures and potential therapeutics in renal cell carcinomas: Insights from a comparative analysis of subtypes

Renal cell carcinomas (RCCs) are among the highest causes of cancer mortality. Although transcriptome profiling studies in the last decade have made significant molecular findings on RCCs, effective diagnosis and treatment strategies have yet to be achieved due to lack of adequate screening and comparative profiling of RCC subtypes. In this study, a comparative analysis was performed on RNA-seq based transcriptome data from each RCC subtype, namely clear cell RCC (KIRC), papillary RCC (KIRP) and kidney chromophobe (KICH), and mutual or subtype-specific reporter biomolecules were identified at RNA, protein, and metabolite levels by the integration of expression profiles with genome-scale biomolecular networks. This approach revealed already-known biomarkers in RCCs as well as novel biomarker candidates and potential therapeutic targets. Our findings also pointed out the incorporation of the molecular mechanisms of KIRC and KIRP, whereas KICH was shown to have distinct molecular signatures. Furthermore, considering the Dipeptidyl Peptidase 4 (DPP4) receptor as a potential therapeutic target specific to KICH, several drug candidates such as ZINC6745464 were identified through virtual screening of ZINC molecules. In this study, we reported valuable data for further experimental and clinical efforts, since the proposed molecules have significant potential for screening and therapeutic purposes in RCCs.

FAT4 silencing promotes epithelial-to-mesenchymal transition and invasion via regulation of YAP and β-catenin activity in ovarian cancer

Background

The adhesion molecule, FAT4, has a tumor suppressor function with a critical role in the epithelial-to-mesenchymal-transition (EMT) and anti-malignant growth in several cancers. No study has investigated yet its role in epithelial ovarian cancer (EOC) progression. In the present study, we examined the role of FAT4 in proliferation and metastasis, and its mechanisms of interaction in these processes.

Methods

We have performed cell viability, colony formation, and invasion assays in ovarian cancer cells treated with siRNA to knockdown FAT4 gene expression. The regulatory effects of FAT4 on proteins involved in apoptotic, Wnt, Hippo, and retinoblastoma signaling pathways were evaluated by Western blotting following FAT4 repression. Also, 426 ovarian tumor samples and 88 non-tumor samples from the Gene Expression Profiling Interactive Analysis (GEPIA) database were analyzed for the expression of FAT4. Pearson’s correlation was performed to determine the correlation between FAT4 and the E2F5, cyclin D1, cdk4, and caspase 9 expressions.

Results

Lower expression of FAT4 was observed in ovarian cancer cell lines and human samples as compared to non-malignant tissues. This down-regulation seems to enhance cell viability, invasion, and colony formation. Silencing FAT4 resulted in the upregulation of E2F5, vimentin, YAP, β-catenin, cyclin D1, cdk4, and Bcl2, and in the downregulation of GSK-3-β, and caspase 9 when compared to control. Furthermore, regulatory effects of FAT4 on the EMT and aggressive phenotype seem to occur through Hippo, Wnt, and cell cycle pathways.

Conclusion

FAT4 downregulation promotes increased growth and invasion through the activation of Hippo and Wnt-β-catenin pathways.

Flavonoids in Ageratum conyzoides L. Exert Potent Antitumor Effects on Human Cervical Adenocarcinoma HeLa Cells In Vitro and In Vivo

The Ageratum conyzoides L. (A. conyzoides) is commonly used as a traditional medicine, and its antitumor effects have also been studied. However, the functional roles of flavonoids in A. conyzoides in antitumor activities have not been clarified. The present study is aimed at investigating the biological effects of flavonoids in A. conyzoides on human cervical adenocarcinoma. Firstly, we detected that flavonoids in A. conyzoides significantly inhibited the proliferation, invasion, migration, and clonality of human cervical adenocarcinoma HeLa cells in vitro. Furthermore, we found that flavonoids in A. conyzoides induced significant S phase arrest and apoptosis and obviously decreased the intracellular reactive oxygen species (ROS) level in HeLa cells. Finally, we found that flavonoids in A. conyzoides significantly inhibited the HeLa xenograft tumor growth and epithelial-mesenchymal transition (EMT) in vivo. In conclusion, our results demonstrated the obvious antitumor effects of flavonoids in A. conyzoides on HeLa cells, suggesting that flavonoids in A. conyzoides could be provided as a novel therapeutic compound for human cervical adenocarcinoma.

Gauging the Impact of Cancer Treatment Modalities on Circulating Tumor Cells (CTCs)

The metastatic cascade consists of multiple complex steps, but the belief that it is a linear process is diminishing. In order to metastasize, cells must enter the blood vessels or body cavities (depending on the cancer type) via active or passive mechanisms. Once in the bloodstream and/or lymphatics, these cancer cells are now termed circulating tumor cells (CTCs). CTC numbers as well as CTC clusters have been used as a prognostic marker with higher numbers of CTCs and/or CTC clusters correlating with an unfavorable prognosis. However, we have very limited knowledge about CTC biology, including which of these cells are ultimately responsible for overt metastatic growth, but due to the fact that higher numbers of CTCs correlate with a worse prognosis; it would seem appropriate to either limit CTCs and/or their dissemination. Here, we will discuss the different cancer treatments which may inadvertently promote the mobilization of CTCs and potential CTC therapies to decrease metastasis.

Up-regulation of FAT4 enhances the chemosensitivity of colorectal cancer cells treated by 5-FU

BACKGROUND

Colorectal cancer (CRC) has high mortality, and 5-fluorouracil (5-FU) is a common clinical chemotherapeutic drug. The current study aimed to investigate the role of FAT4 in chemosensitivity of CRC cells treated by 5-FU.

METHODS

The immunohistochemistry and qRT-PCR was conducted to measure the FAT4 expression in CRC and adjacent tissues. The FAT4 expression was determined by qRT-PCR and Western blot, comparison of FAT expression between normal and several CRC cell lines was then made, so as to identify cell lines with the highest (LS174T) and the lowest (SW-620) expressions of FAT4. The effects of 5-FU stimulation at various doses on cell viability were determined by CCK-8, and the level of FAT4 was also measured. After FAT4 knockdown in LS174T or FAT4 overexpression in SW-620 with or without pretreatment of 5-FU (30 µg/mL), cell growth, colony formation, cell migration and invasion, angiogenesis were determined by flow cytometry, wound-healing, transwell assay and tube formation assay, respectively. The expression levels of epithelial-mesenchymal transition (EMT) markers were detected by qRT-PCR and Western blot.

RESULTS

FAT4 was down-regulated in CRC tissues and cells, cell viability of CRC cells was decreased. The level of FAT4 was increased with the increase of 5-FU concentrations. Moreover, 5-FU stimulation increased FAT4 expression, and reduced cell proliferation, migration, invasion, angiogenesis and cell EMT process, furthermore, such effects of 5-FU stimulation could be enhanced by FAT4 overexpression but reversed by FAT4 knockdown.

CONCLUSIONS

Upregulation of FAT4 could increase the sensitivity of CRC cells to 5-FU.

Histone demethylase RBP2 mediates the blast crisis of chronic myeloid leukemia through an RBP2/PTEN/BCR-ABL cascade

Epigenetic disorders play a key role in tumorigenesis and development, among which histone methylation abnormalities are common. While patients living with chronic myeloid leukemia in the chronic phase (CML-CP) have a good response to TKI, blastic phase (CML-BP) patients demonstrate poor efficacy and high fatality rates. However, while the mechanism of blast crisis of chronic myeloid leukemia remains unclear, high expression and activation of BCR-ABL are usually related to CML blast crisis transition. We found that histone H3 lysine 4 (H3K4) demethylase RBP2 expression is negatively correlated with BCR-ABL expression, which suggests a regulatory link between these two genes. We also discovered that RBP2 mediates the dephosphorylation of BCR-ABL by directly downregulating PTEN expression, depending on histone demethylase activity, while PTEN targets protein phosphatase activity of BCR-ABL, a phosphatase which directly dephosphorylates BCR-ABL. In clinical specimens, the mRNA expression of RBP2 was found to be positively correlated with that of PTEN. These data suggest that the under-expression of RBP2 promotes blast crisis transition by activating an RBP2/PTEN/BCR-ABL cascade.

HSPD1 repressed E-cadherin expression to promote cell invasion and migration for poor prognosis in oral squamous cell carcinoma

Buccal mucosa squamous cell carcinoma (BMSCC) is one of major subsites of oral cancer and is associated with a high rate of metastasis and poor prognosis. Heat shock proteins (HSPs) act as potential prognostic biomarkers in many cancer types. However, the role of HSPD1 in oral cancer, especially in BMSCC, is still unknown. Through data analysis with The Cancer Genome Atlas (TCGA), we found the association of HSPD1 gene expression with tumorigenesis and poor prognosis in oral cancer patients. Our cohort study showed that higher HSPD1 protein level was associated with tumorigenesis and poor prognosis in BMSCC patients with lymph node invasion, suggesting that HSPD1 may be involved in tumor metastasis. Moreover, knockdown of HSPD1 induced E-cadherin expression and decreased the migration and invasion of BMSCC cells. In contrast, ectopic expression of HSPD1 diminished E-cadherin expression and promoted the migration/invasion of BMSCC cells. Further, HSPD1 regulated RelA activation to repress E-cadherin expression, enhancing the migration and invasion of BMSCC cells. Furthermore, HSPD1 protein level was inversely correlated with E-cadherin protein level in tumor tissues and co-expression of high HSPD1/low E-cadherin showed a significant association with poor prognosis in BMSCC patients. Taken together, HSPD1 might repress E-cadherin expression and promote metastatic characters of BMSCC cells for poor prognosis of BMSCC patients.

Controlling metastatic cancer: the role of phytochemicals in cell signaling

PURPOSE

Cancer is a serious health issue and a leading cause of death worldwide. Most of the cancer patients (approximately 90%) do not die from the consequences of the primary tumor development, but due to a heavily treatable metastatic invasion. During the lengthy multistep process of carcinogenesis, there are a lot of opportunities available to reverse or slow down the tissue invasion or the process of tumor metastasis formation.

RESULTS

Current research has brought many promising results from anti-metastatic experimental studies, and has shown that chemoprevention by natural or semisynthetic phytochemicals with plethora of biological activities could be one of the potentially effective options in the fight against this problem. However, there is a lack of clinical trials to confirm these findings. In this review, we focused on summarization and discussion of the general features of metastatic cancer, and recent preclinical and clinical studies dealing with anti-metastatic potential of various plant-derived compounds.

CONCLUSIONS

Based on our findings, we can conclude and confirm our hypothesis that phytochemicals with pleiotropic anticancer effects can be very useful in retarding and/or reversing the metastasis process, and can also be used to prevent tissue invasion and metastases. But, further studies in this area are certainly necessary and desirable.

Pathogenic and Therapeutic Role of H3K4 Family of Methylases and Demethylases in Cancers

Histone modifications occupy an essential position in the epigenetic landscape of the cell, and their alterations have been linked to cancers. Histone 3 lysine 4 (H3K4) methylation has emerged as a critical epigenetic cue for the regulation of gene transcription through dynamic modulation by several H3K4 methyltransferases (writers) and demethylases (erasers). Any disturbance in the delicate balance of writers and erasers can result in the mis-regulation of H3K4 methylation, which has been demonstrated in several human cancers. Therefore, H3K4 methylation has been recognized as a putative therapeutic or prognostic tool and drug trials of different inhibitors of this process have demonstrated promising results. Henceforth, more detailed knowledge of H3K4 methylation is utmost important for elucidating the complex cellular processes, which might help in improving the disease outcome. The primary focus of this review will be directed on deciphering the role of H3K4 methylation along with its writers/erasers in different cancers.

FAT4 regulates the EMT and autophagy in colorectal cancer cells in part via the PI3K-AKT signaling axis

BACKGROUND

FAT4 functions as a tumor suppressor, and previous findings have demonstrated that FAT4 can inhibit the epithelial-to-mesenchymal transition (EMT) and the proliferation of gastric cancer cells. However, few studies have investigated the role of FAT4 in the development of colorectal cancer (CRC). The current study aimed to detect the role of FAT4 in the invasion, migration, proliferation and autophagy of CRC and elucidate the probable molecular mechanisms through which FAT4 interacts with these processes.

METHODS

Transwell invasion assays, MTT assays, transmission electron microscopy, immunohistochemistry and western blotting were performed to evaluate the migration, invasion, proliferation and autophagy abilities of CRC cells, and the levels of active molecules involved in PI3K/AKT signaling were examined through a western blotting analysis. In addition, the function of FAT4 in vivo was assessed using a tumor xenograft model.

RESULTS

FAT4 expression in CRC tissues was weaker than that in nonmalignant tissues and could inhibit cell invasion, migration, and proliferation by promoting autophagy in vitro. Furthermore, the regulatory effects of FAT4 on autophagy and the EMT were partially attributed to the PI3K-AKT signaling pathway. The results in vivo also showed that FAT4 modulated CRC tumorigenesis.

CONCLUSION

FAT4 can regulate the activity of PI3K to promote autophagy and inhibit the EMT in part through the PI3K/AKT/mTOR and PI3K/AKT/GSK-3β signaling pathways.

Biology and targeting of the Jumonji-domain histone demethylase family in childhood neoplasia: a preclinical overview

INTRODUCTION

Epigenetic mechanisms of gene regulatory control play fundamental roles in developmental morphogenesis, and, as more recently appreciated, are heavily implicated in the onset and progression of neoplastic disease, including cancer. Many epigenetic mechanisms are therapeutically targetable, providing additional incentive for understanding of their contribution to cancer and other types of neoplasia. Areas covered: The Jumonji-domain histone demethylase (JHDM) family exemplifies many of the above traits. This review summarizes the current state of knowledge of the functions and pharmacologic targeting of JHDMs in cancer and other neoplastic processes, with an emphasis on diseases affecting the pediatric population. Expert opinion: To date, the JHDM family has largely been studied in the context of normal development and adult cancers. In contrast, comparatively few studies have addressed JHDM biology in cancer and other neoplastic diseases of childhood, especially solid (non-hematopoietic) neoplasms. Encouragingly, the few available examples support important roles for JHDMs in pediatric neoplasia, as well as potential roles for JHDM pharmacologic inhibition in disease management. Further investigations of JHDMs in cancer and other types of neoplasia of childhood can be expected to both enlighten disease biology and inform new approaches to improve disease outcomes.

Dynamic regulation of epigenetic demethylation by oxygen availability and cellular redox

The chromatin structure of the mammalian genome must facilitate both precisely-controlled DNA replication together with tightly-regulated gene transcription. This necessarily involves complex mechanisms and processes which remain poorly understood. It has long been recognised that the epigenetic landscape becomes established during embryonic development and acts to specify and determine cell fate. In addition, the chromatin structure is highly dynamic and allows for both cellular reprogramming and homeostatic modulation of cell function. In this respect, the functions of epigenetic "erasers", which act to remove covalently-linked epigenetic modifications from DNA and histones are critical. The enzymatic activities of the TET and JmjC protein families have been identified as demethylases which act to remove methyl groups from DNA and histones, respectively. Further, they are characterised as members of the Fe(II)- and 2-oxoglutarate-dependent dioxygenase superfamily. This provides the intriguing possibility that their enzymatic activities may be modulated by cellular metabolism, oxygen availability and redox-based mechanisms, all of which are likely to display dynamic cell- and tissue-specific patterns of flux. Here we discuss the current evidence for such [O₂]- and redox-dependent regulation of the TET and Jmjc demethylases and the potential physiological and pathophysiological functional consequences of such regulation.

Insights into the Action of Inhibitor Enantiomers against Histone Lysine Demethylase 5A

Isomers of chiral drugs can exhibit marked differences in biological activities. We studied the binding and inhibitory activities of 12 compounds against KDM5A. Among them are two pairs of enantiomers representing two distinct inhibitor chemotypes, namely, ( R)- and ( S)-2-((2-chlorophenyl)(2-(piperidin-1-yl)ethoxy)methyl)-1 H-pyrrolo[3,2- b]pyridine-7-carboxylic acid (compounds N51 and N52) and ( R) - and ( S) -N-(1-(3-isopropyl-1 H-pyrazole-5-carbonyl)pyrrolidin-3-yl)cyclopropanecarboxamide (compounds N54 and N55). In vitro, the S enantiomer of the N51/N52 pair (N52) and the R enantiomer of the N54/N55 pair (N54) exhibited about 4- to 5-fold greater binding affinity. The more potent enzyme inhibition of KDM5A by the R-isoform for the cell-permeable N54/N55 pair translated to differences in growth inhibitory activity. We determined structures of the KDM5A catalytic domain in complex with all 12 inhibitors, which revealed the interactions (or lack thereof) responsible for the differences in binding affinity. These results provide insights to guide improvements in binding potency and avenues for development of cell permeable inhibitors of the KDM5 family.

Interleukin-6/signal transducer and activator of transcription 3 promotes prostate cancer resistance to androgen deprivation therapy via regulating pituitary tumor transforming gene 1 expression

Prostate cancer can progress from androgen dependence to androgen deprivation resistance with some unknown mechanisms. The current study aims to explore the possible role of pituitary tumor transforming gene1 (PTTG1) in castration-resistant prostate cancer (CRPC). Initially, we found that PTTG1 expression was significantly increased in androgen-independent prostate cancer cell lines PC3, DU145 and CRPC specimens compared with that in androgen-dependent prostate cancer cell line LNCaP and initial prostate cancer specimens. PTTG1 overexpression significantly enhanced the cell survival rate, clonality and tumorigenicity in LNCaP cells upon androgen-deprivation therapy (ADT). While knockdown of PTTG1 expression significantly elevated the sensitivity of DU145 cells to ADT. The effects of PTTG1 overexpression on LNCaP cells may be ascribed to the induced EMT and increased CD44⁺ CD24^- cancer stem cell population. Furthermore, we detected that PTTG1 expression was regulated by interleukin-6 via activated signal transducer and activator of transcription 3 (STAT3) directly binding to the region -500 to +1 of PTTG1 promoter in LNCaP cells. In conclusion, our results elucidate that interleukin-6/STAT3 activation can increase PTTG1 expression and, consequently, promote the resistance to ADT in CRPC by inducing EMT and increasing the cancer stem cell population, suggesting that PTTG1 may be a novel therapeutic target for CRPC.

Histone demethylase KDM5A inhibits glioma cells migration and invasion by down regulating ZEB1

Malignant gliomas are highly lethal cancers worldwide as tumor cells infiltrate to healthy brain tissue invariably. Histone demethylase KDM5A as an oncogene or tumor suppressor in cancer still has been controversial. KDM5A may have a different function in different type cancer cells. However, the specific roles of KDM5A in the progression of glioma remain undiscovered. In this study, we found that compared with primary glioma, metastasis glioma had low KDM5A levels. Besides, lower KDM5A levels were linked to poor survival in glioma cancer patients, indicating that KDM5A is a new prognostic marker for glioma cancer. KDM5A knockdown increases the invasive abilities of glioma cancer cells and changes the EMT markers. A mechanism, KDM5A suppressing the expression of ZEB1, and its catalytic activity is indispensable for anti-invasive function. Our study revealed that histone demethylase KDM5A exerts anti-invasiveness function partly through repressing oncogenic ZEB1 expression by mediating H3K4 demethylation. We also demonstrate that ZEB1 play a crucial role in KDM5A induced function. In summary, in this study, we showed that KDM5A has a crucial role in glioma and therefore may serve as a novel therapeutic target and prognostic marker in glioma.

The Role of Compounds Derived from Natural Supplement as Anticancer Agents in Renal Cell Carcinoma: A Review

Renal Cell Carcinoma (RCC) is the most prominent kidney cancer derived from renal tubules and accounts for roughly 85% of all malignant kidney cancer. Every year, over 60,000 new cases are registered, and about 14,000 people die from RCC. The incidence of this has been increasing significantly in the U.S. and other countries. An increased understanding of molecular biology and the genomics of RCC has uncovered several signaling pathways involved in the progression of this cancer. Significant advances in the treatment of RCC have been reported from agents approved by the Food and Drug Administration (FDA) that target these pathways. These agents have become drugs of choice because they demonstrate clinical benefit and increased survival in patients with metastatic disease. However, the patients eventually relapse and develop resistance to these drugs. To improve outcomes and seek approaches for producing long-term durable remission, the search for more effective therapies and preventative strategies are warranted. Treatment of RCC using natural products is one of these strategies to reduce the incidence. However, recent studies have focused on these chemoprevention agents as anti-cancer therapies given they can inhibit tumor cell grow and lack the severe side effects common to synthetic compounds. This review elaborates on the current understanding of natural products and their mechanisms of action as anti-cancer agents. The present review will provide information for possible use of these products alone or in combination with chemotherapy for the prevention and treatment of RCC.

Cancer stem cells and differentiation therapy

Cancer stem cells can generate tumors from only a small number of cells, whereas differentiated cancer cells cannot. The prominent feature of cancer stem cells is its ability to self-renew and differentiate into multiple types of cancer cells. Cancer stem cells have several distinct tumorigenic abilities, including stem cell signal transduction, tumorigenicity, metastasis, and resistance to anticancer drugs, which are regulated by genetic or epigenetic changes. Like normal adult stem cells involved in various developmental processes and tissue homeostasis, cancer stem cells maintain their self-renewal capacity by activating multiple stem cell signaling pathways and inhibiting differentiation signaling pathways during cancer initiation and progression. Recently, many studies have focused on targeting cancer stem cells to eradicate malignancies by regulating stem cell signaling pathways, and products of some of these strategies are in preclinical and clinical trials. In this review, we describe the crucial features of cancer stem cells related to tumor relapse and drug resistance, as well as the new therapeutic strategy to target cancer stem cells named "differentiation therapy."

Epithelial-to-Mesenchymal Transition: Epigenetic Reprogramming Driving Cellular Plasticity

Epithelial-to-mesenchymal transition (EMT) is a process in which epithelial cells lose their junctions and polarity to gain a motile mesenchymal phenotype. EMT is essential during embryogenesis and adult physiological processes like wound healing, but is aberrantly activated in pathological conditions like fibrosis and cancer. A series of transcription factors (EMT-inducing transcription factor; EMT-TF) regulate the induction of EMT by repressing the transcription of epithelial genes while activating mesenchymal genes through mechanisms still debated. The nuclear interaction of EMT-TFs with larger protein complexes involved in epigenetic genome modulation has attracted recent attention to explain functions of EMT-TFs during reprogramming and cellular differentiation. In this review, we discuss recent advances in understanding the interplay between epigenetic regulators and EMT transcription factors and how these findings could be used to establish new therapeutic approaches to tackle EMT-related diseases.

JARID1 Histone Demethylases: Emerging Targets in Cancer

JARID1 proteins are histone demethylases that both regulate normal cell fates during development and contribute to the epigenetic plasticity that underlies malignant transformation. This H3K4 demethylase family participates in multiple repressive transcriptional complexes at promoters and has broader regulatory effects on chromatin that remain ill-defined. There is growing understanding of the oncogenic and tumor suppressive functions of JARID1 proteins, which are contingent on cell context and the protein isoform. Their contributions to stem cell-like dedifferentiation, tumor aggressiveness, and therapy resistance in cancer have sustained interest in the development of JARID1 inhibitors. Here we review the diverse and context-specific functions of the JARID1 proteins that may impact the utilization of emerging targeted inhibitors of this histone demethylase family in cancer therapy.

Clear Cell Renal Cell Carcinoma is linked to Epithelial-to-Mesenchymal Transition and to Fibrosis

Clear cell renal cell carcinoma (ccRCC) represents the most common type of kidney cancer with high mortality in its advanced stages. Our study aim was to explore the correlation between tumor epithelial-to-mesenchymal transition (EMT) and patient survival. Renal biopsies of tumorous and adjacent nontumorous tissue were taken with a 16 g needle from our patients (n = 26) undergoing partial or radical nephrectomy due to ccRCC RNA sequencing libraries were generated using Illumina TruSeq® Access library preparation protocol and TruSeq Small RNA library preparation kit. Next generation sequencing (NGS) was performed on Illumina HiSeq2500. Comparative analysis of matched sample pairs was done using the Bioconductor Limma/voom R-package. Liquid chromatography-tandem mass spectrometry and immunohistochemistry were applied to measure and visualize protein abundance. We detected an increased generic EMT transcript score in ccRCC Gene expression analysis showed augmented abundance of AXL and MMP14, as well as down-regulated expression of KL (klotho). Moreover, microRNA analyses demonstrated a positive expression correlation of miR-34a and its targets MMP14 and AXL Survival analysis based on a subset of genes from our list EMT-related genes in a publicly available dataset showed that the EMT genes correlated with ccRCC patient survival. Several of these genes also play a known role in fibrosis. Accordingly, recently published classifiers of solid organ fibrosis correctly identified EMT-affected tumor samples and were correlated with patient survival. EMT in ccRCC linked to fibrosis is associated with worse survival and may represent a target for novel therapeutic interventions.

Epithelial-to-mesenchymal transition in tumor progression

The epithelial-to-mesenchymal transition (EMT) is a biological process in which a non-motile epithelial cell changes to a mesenchymal state with invasive capacities. However, the EMT program is involved in both physiological and pathological processes. Cancer-associated EMT is known to contribute to increase invasiveness and metastasis, resistance to therapies, and generation of cell populations with stem cell-like characteristics and therefore is deeply involved in tumor progression. This process is finely orchestrated by multiple signaling pathways and regulatory transcriptional networks. The hallmark of EMT is the loss of epithelial surface markers, mainly E-cadherin, and the acquisition of mesenchymal phenotype. These events can be mediated by EMT transcription factors which can cooperate with several enzymes to repress the E-cadherin expression and regulate EMT at the epigenetic and post-translational level. A growing body of evidence indicates that cancer cells can reside in various phenotypic states along the EMT spectrum, where cells can jointly retain epithelial traits with mesenchymal ones. This type of phenotypic plasticity endows cancer cells with tumor-initiating potential. The identification of the signaling pathways and modulators that lead to activation of EMT programs during these disease processes is providing new insights into the plasticity of cellular phenotypes and possible therapeutic interventions.

Zinc suppresses stem cell properties of lung cancer cells through protein kinase C-mediated β-catenin degradation

Highly tumorigenic cancer stem cells (CSCs) residing in most cancers are responsible for cancer progression and treatment failure. Zinc is an element regulator of several cell functions; however, its role in regulation of stem cell program in lung cancer has not been demonstrated. The present study reveals for the first time that zinc can suppress stem cell properties of lung cancer cells. Such findings were proved in different lung cancer cell lines (H460, H23, and H292) and it was found that CSC markers (CD133 and ALDH1A1), stem cell-associated transcription factors (Oct4, Nanog, and Sox-2), and the ability to form tumor spheroid were dramatically suppressed by zinc treatments. Zinc was found to activate protein kinase C-α (PKCα) that further phosphorylated and mediated β-catenin degradation through the ubiquitin-proteasomal pathway. Zinc was found to increase the β-catenin-ubiquitin complex, which can be inhibited by a specific PKC inhibitor, bisindolylmaleimide I. Using specific reactive oxygen species detection and antioxidants, we have demonstrated that superoxide anions generated by zinc are a key upstream mechanism for PKCα activation leading to the subsequent suppression of stem cell features of lung cancer. Zinc increased cellular superoxide anions and the addition of superoxide anion scavenger prevented the activation of PKCα and β-catenin degradation. These findings indicate a novel role for zinc regulation in the PKCα/β-catenin pathway and explain an important mechanism for controlling of stem cell program in lung cancer cells.

Novel targets in the treatment of neuroendocrine tumors: RBP2

Retinoblastoma binding protein 2, also known as RBP2, JARID1A or KDM5A, is an H3K4 demethylase implicated in a variety of non-neuroendocrine, and more recently, neuroendocrine tumors (NETs). NETs are tumors that form from neuroendocrine cells in tissues of the GI tract, endocrine pancreas, lung, skin and other tissues. RBP2 is expressed at abnormally high levels in NETs and recent work demonstrates that modulation of RBP2 in vitro and in vivo impacts end points of tumorigenesis. Interestingly, the demethylase activity of RBP2 is not exclusively responsible for these changes, as RBP2's binding partners may mediate its activity in a tissue- or context-dependent manner. Here, we discuss the features of RBP2 and its role in cell cycle regulation, angiogenesis and drug resistance in cancer.

Emerging Biological Principles of Metastasis

Metastases account for the great majority of cancer-associated deaths, yet this complex process remains the least understood aspect of cancer biology. As the body of research concerning metastasis continues to grow at a rapid rate, the biological programs that underlie the dissemination and metastatic outgrowth of cancer cells are beginning to come into view. In this review we summarize the cellular and molecular mechanisms involved in metastasis, with a focus on carcinomas where the most is known, and we highlight the general principles of metastasis that have begun to emerge.

ATF2 predicts poor prognosis and promotes malignant phenotypes in renal cell carcinoma

Background

Activating transcription factor 2 (ATF2) is a basic helix-loop-helix transcription factor, which has been shown to participate in the pathobiology of numerous cancers. However, the role of ATF2 in renal cell carcinoma (RCC) remains unclear.

Methods

ATF2 knockdown and overexpression studies were performed in RCC cells to evaluate changes in cell viability, cell cycle, apoptosis, migration and invasion. Xenograft models were used to examine the tumorigenic and metastatic capability of RCC cells upon ATF2 suppression. The expression of ATF2 in human RCC samples was determined using immunohistochemistry on a tissue microarray.

Results

ATF2 knockdown in RCC cells reduced their proliferative and metastatic potentials, whereas ATF2 overexpression enhanced these properties. Mechanistic studies revealed that the transcription of CyclinB1, CyclinD1, Snail and Vimentin was directly regulated by ATF2 in RCC cells. Moreover, ATF2 was shown to be highly expressed in RCC tissues, especially in tumors with metastases. High expression of ATF2 correlated with aggressive clinico-pathological characteristics and predicted poor prognosis of RCC patients.

Conclusions

ATF2 exerts an oncogenic role in RCC and could serve as an important prognostic biomarker.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0383-2) contains supplementary material, which is available to authorized users.

Targeting the Epithelial-to-Mesenchymal Transition: The Case for Differentiation-Based Therapy

Although important strides have been made in targeted therapy for certain leukemias and subtypes of breast cancer, the standard of care for most carcinomas still involves chemotherapy, radiotherapy, surgery, or a combination of these. Two processes serve as obstacles to the successful treatment of carcinomas. First, a majority of deaths from these types of cancers occurs as a result of distant metastases and not the primary tumors themselves. Second, subsets of cells that are able to survive conventional therapy drive the aggressive relapse of the tumors, often in forms that are resistant to treatment. A frequently observed feature of malignant carcinomas is the loss of epithelial traits and the gain of certain mesenchymal ones that are programmed by the cell-biological program termed the epithelial-to-mesenchymal transition (EMT). The EMT program can confer (i) an ability to disseminate, (ii) an ability to become stem-like tumor-initiating cells, (iii) an ability to found new tumor colonies at distant anatomical sites, and (iv) an elevated resistance to therapy. These multiple powers of the EMT program explain why it has become an attractive target for therapeutic intervention. Recent work has revealed the variable nature of the EMT, with multiple versions of the program being observed depending on the tissue context and the stage of tumor progression. In this review, we attempt to crystallize emerging concepts in the research on EMT and stemness and discuss the benefits of using a differentiation-based therapeutic strategy for the eradication of stem-like populations that have adopted various versions of the EMT program.