Epigenetic Reprogramming of TGF-β Signaling in Breast Cancer

A chronic signaling TGFb zebrafish reporter identifies immune response in melanoma

Developmental signaling pathways associated with growth factors such as TGFb are commonly dysregulated in melanoma. Here we identified a human TGFb enhancer specifically activated in melanoma cells treated with TGFB1 ligand. We generated stable transgenic zebrafish with this TGFb Induced Enhancer driving green fluorescent protein (TIE:EGFP). TIE:EGFP was not expressed in normal melanocytes or early melanomas but was expressed in spatially distinct regions of advanced melanomas. Single-cell RNA-sequencing revealed that TIE:EGFP+ melanoma cells down-regulated interferon response while up-regulating a novel set of chronic TGFb target genes. ChIP-sequencing demonstrated that AP-1 factor binding is required for activation of chronic TGFb response. Overexpression of SATB2, a chromatin remodeler associated with tumor spreading, showed activation of TGFb signaling in early melanomas. Confocal imaging and flow cytometric analysis showed that macrophages localize to TIE:EGFP+ regions and preferentially phagocytose TIE:EGFP+ melanoma cells compared to TIE:EGFP- melanoma cells. This work identifies a TGFb induced immune response and demonstrates the need for the development of chronic TGFb biomarkers to predict patient response to TGFb inhibitors.

Epigenetic regulation of TGF-β pathway and its role in radiation response

PURPOSE

Transforming growth factor (TGF-β) plays a dual role in tumor progression as well as a pivotal role in radiation response. TGF-β-related epigenetic regulations, including DNA methylation, histone modifications (including methylation, acetylation, phosphorylation, ubiquitination), chromatin remodeling and non-coding RNA regulation, have been found to affect the occurrence and development of tumors as well as their radiation response in multiple dimensions. Due to the significance of radiotherapy in tumor treatment and the essential roles of TGF-β signaling in radiation response, it is important to better understand the role of epigenetic regulation mechanisms mediated by TGF-β signaling pathways in radiation-induced targeted and non-targeted effects.

CONCLUSIONS

By revealing the epigenetic mechanism related to TGF-β-mediated radiation response, summarizing the existing relevant adjuvant strategies for radiotherapy based on TGF-β signaling, and discovering potential therapeutic targets, we hope to provide a new perspective for improving clinical treatment.

The Implication of Growth Arrest-Specific 5 rs145204276 Polymorphism and Serum Expression of Sirtuin 1, Transforming Growth Factor-Beta, and microRNA-182 in Breast Cancer

Background

Breast cancer (BC) patients have a higher chance of survival if it is diagnosed at an early stage, which is essential for efficient treatment of the condition. The results of an elevated risk of cancer, including BC, previously associated with the ins/del polymorphism rs145204276 in the promoter region of growth arrest-specific 5 (GAS5) are still up for debate. Thus, this study aimed to appraise the frequency of the GAS5 rs145204276 variant with BC risk and demonstrate the potential impact of the sirtuin 1 (SIRT-1), transforming growth factor-beta (TGF-β), and microRNA-182 (miR-182) expression and their diagnostic value in BC.

Methods

Blood samples of 155 patients with BC and fibroadenoma and 80 healthy controls were analyzed for GAS5 rs145204276 single nucleotide polymorphism (SNP), SIRT-1, TGF-β, and miRNA-182 expression levels.

Results

Ins/ins genotype and ins allele frequencies for GAS5 rs145204276 were considerably higher in BC patients compared with controls. Patients with BC had significantly greater serum levels of TGF-β, miR-182, and SIRT-1 expression.

Conclusions

The SIRT-1, TGF-β, and miR-182 genes provide novel, noninvasive diagnostic biomarkers for BC.

Multifaceted TGF-β signaling, a master regulator: From bench-to-bedside, intricacies, and complexities

Physiological embryogenesis and adult tissue homeostasis are regulated by transforming growth factor-β (TGF-β), an evolutionarily conserved family of secreted polypeptide factors, acting in an autocrine and paracrine manner. The role of TGF-β in inflammation, fibrosis, and cancer is complex and sometimes even contradictory, exhibiting either inhibitory or promoting effects depending on the stage of the disease. Under pathological conditions, especially fibrosis and cancer, overexpressed TGF-β causes extracellular matrix deposition, epithelial-mesenchymal transition, cancer-associated fibroblast formation, and/or angiogenesis. In this review article, we have tried to dive deep into the mechanism of action of TGF-β in inflammation, fibrosis, and carcinogenesis. As TGF-β and its downstream signaling mechanism are implicated in fibrosis and carcinogenesis blocking this signaling mechanism appears to be a promising avenue. However, targeting TGF-β carries substantial risk as this pathway is implicated in multiple homeostatic processes and is also known to have tumor-suppressor functions. There is a need for careful dosing of TGF-β drugs for therapeutic use and patient selection.

TGF-β in correlation with tumor progression, immunosuppression and targeted therapy in colorectal cancer

Colorectal cancer (CRC) is a complex malignancy responsible for the second-highest cancer deaths worldwide. TGF-β maintains normal cellular homeostasis by inhibiting the cell cycle and inducing apoptosis, but its elevated level is correlated with colorectal cancer progression, as TGF-β is a master regulator of the epithelial-to-mesenchymal transition, a critical step of metastasis. Tumors, including CRC, use elevated TGF-β levels to avoid immune surveillance by modulating immune cell differentiation, proliferation, and effector function. Presently, the treatment of advanced CRC is mainly based on chemotherapy, with multiple adverse effects. Thus, there is a need to develop alternate tactics because CRC continue to be mostly resistant to the present therapeutic regimen. TGF-β blockade has emerged as a promising therapeutic target in cancer therapy. Blocking TGF-β with phytochemicals and other molecules, such as antisense oligonucleotides, monoclonal antibodies, and bifunctional traps, alone or in combination, may be a safer and more effective way to treat CRC. Furthermore, combination immunotherapy comprising TGF-β blockers and immune checkpoint inhibitors is gaining popularity because both molecules work synergistically to suppress the immune system. Here, we summarize the current understanding of TGF-β as a therapeutic target for managing CRC and its context-dependent tumor-promoting or tumor-suppressing nature.

Multi-omics approaches establishing histone modification based prognostic model in glioma patients and further verification of the carcinogenesis mechanism

Glioblastoma (GBM) emerges as the most common malignant brain tumor. Histone modifications, as an epigenetic regulatory mechanism of gene expression, are closely associated with malignant tumors. Gene set related to histone modification was extracted from the MSigDB database, and scored by the function of AddModuleScore. Pearson correlation analysis was utilized using the "rcorr" function of "Hmisc" R package. Genes were screened out using the LASSO Cox analysis. TCGA-GBM and CGGA_array_301 cohorts were employed for constructing model and validation. We calculated immune infiltration scores using microenvironment cell populations counter (MCPcounter), single-sample gene set enrichment analysis (ssGSEA), and xCell algorithms. U87-MG and CHG-5 cell lines were utilized to evaluate expression level of TMEM176A by western blot (WB). Transwell, EDU, colony formation analysis (CFA), and CKK-8 assays were conducted to investigate cell proliferation and migration rate. The malignant cells in GBM patients exhibited notable activation in the TGF-β and hypoxia pathway. Histone modifications were associated with adhesion and neuron development in GBM. We identified a model with five significant genes, namely NBEAL1, AEBP1, TMEM176A, FASTK, and CD81, with prognostic efficacy. Additionally, we observed increased infiltration of T cells and CD8+ T cells in the high-risk (HR) group. 5-Fluorouracil_1073 and Taselisib_1561 were predicted as potential treatment options for GBM patients, while ABT737_1910 and Wnt_C59-1622 exhibited superior response in GBM patients of the HR group. A spike in the TP53 mutation rate was observed in the HR group. TMEM176A played a role in regulating cell proliferation and migration in vitro. We presented a novel prognostic model for patients with GBM, based on histone modification-related genes. In addition, we identified the crucial role of the TMEM176A in the regulation of GBM carcinogenic phenotypes for the first time.

Long non-coding RNAs as the critical regulators of PI3K/AKT, TGF-β, and MAPK signaling pathways during breast tumor progression

Breast cancer (BC) as one of the most common causes of human deaths among women, is always considered one of the global health challenges. Despite various advances in diagnostic and therapeutic methods, a significant percentage of BC patients have a poor prognosis due to the lack of therapeutic response. Therefore, investigating the molecular mechanisms involved in BC progression can improve the therapeutic and diagnostic strategies in these patients. Cytokine and growth factor-dependent signaling pathways play a key role during BC progression. In addition to cytokines and growth factors, long non-coding RNAs (lncRNAs) have also important roles in regulation of such signaling pathways. Therefore, in the present review we discussed the role of lncRNAs in regulation of PI3K/AKT, MAPK, and TGF-β signaling pathways in breast tumor cells. It has been shown that lncRNAs mainly have an oncogenic role through the promotion of these signaling pathways in BC. This review can be an effective step in introducing the lncRNAs inhibition as a probable therapeutic strategy to reduce tumor growth by suppression of PI3K/AKT, MAPK, and TGF-β signaling pathways in BC patients. In addition, considering the oncogenic role and increased levels of lncRNAs expressions in majority of the breast tumors, lncRNAs can be also considered as the reliable diagnostic markers in BC patients.

Forkhead box L2 is a target of miR-133b and plays an important role in the pathogenesis of non-small cell lung cancer

BACKGROUND

Forkhead box L2 (FOXL2) has been recognized as a transcription factor in the progression of many malignancies, but its role in non-small cell lung cancer (NSCLC) remains unclear. This research clarified on the role of FOXL2 and the specific molecular mechanism in NSCLC.

METHODS

RNA and protein levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting assays. Cell proliferation was examined by cell counting kit-8 (CCK-8) and clonogenic assays. Transwell and wound healing assays were used to detect cell invasion and migration. Cell cycle alterations were assessed by flow cytometry. The relationship between FOXL2 and miR-133b was verified by dual-luciferase reporter assays. In vivo metastasis was monitored in the tail vein-injected mice.

RESULTS

FOXL2 was upregulated in NSCLC cells and tissues. Downregulation of FOXL2 restrained cell proliferation, migration, and invasion and arrested the cell cycle of NSCLC cells. Moreover, FOXL2 promoted the epithelial-mesenchymal transition (EMT) process of NSCLC cells by inducing the transforming growth factor-β (TGF-β)/Smad signaling pathway. miR-133b directly targeted the 3'-UTR of FOXL2 and negatively regulated FOXL2 expression. Knockdown of FOXL2 blocked metastasis in vivo.

CONCLUSIONS

miR-133b downregulates FOXL2 by targeting the 3'-UTR of FOXL2, thereby inhibiting cell proliferation, EMT and metastasis induced by the TGF-β/Smad signaling pathway in NSCLC. FOXL2 may be a potential molecular target for treating NSCLC.

Novel Roles of Nanog in Cancer Cells and Their Extracellular Vesicles

The use of extracellular vesicle (EV)-based vaccines is a strategically promising way to prevent cancer metastasis. The effective roles of immune cell-derived EVs have been well understood in the literature. In the present paper, we focus on cancer cell-derived EVs to enforce, more thoroughly, the use of EV-based vaccines against unexpected malignant cells that might appear in poor prognostic patients. As a model of such a cancer cell with high malignancy, Nanog-overexpressing melanoma cell lines were developed. As expected, Nanog overexpression enhanced the metastatic potential of melanomas. Against our expectations, a fantastic finding was obtained that determined that EVs derived from Nanog-overexpressing melanomas exhibited a metastasis-suppressive effect. This is considered to be a novel role for Nanog in regulating the property of cancer cell-derived EVs. Stimulated by this result, the review of Nanog's roles in various cancer cells and their EVs has been updated once again. Although there was no other case presenting a similar contribution by Nanog, only one case suggested that NANOG and SOX might be better prognosis markers in head and neck squamous cell carcinomas. This review clarifies the varieties of Nanog-dependent phenomena and the relevant signaling factors. The information summarized in this study is, thus, suggestive enough to generate novel ideas for the construction of an EV-based versatile vaccine platform against cancer metastasis.

Tumour budding is a novel marker in breast cancer: the clinical application and future prospects

Breast cancer (BC) is a group of markedly heterogeneous tumours. There are many subtypes with different biological behaviours and clinicopathological characteristics, leading to significantly different prognosis. Despite significant advances in the treatment of BC, early metastatic is a critical factor for poor prognosis in BC patients. Tumour budding (TB) is considered as the first step process of tumour metastasis and is related to the epithelial-mesenchymal transition (EMT). TB has been observed in a variety of cancers, such as colorectal and gastric cancer, and had been considered as a distinct clinicopathological characteristics for early metastasis. However, TB evaluation standards and clinical application are not uniform in BC, as well as its molecular mechanism is not fully understood. Here, we reviewed the interpretation criteria, mechanism, clinicopathological characteristics and clinical application prospects of TB in BC. Key messagesCurrently, tumour budding is a poor prognosis for various solid tumours, also in breast cancer.Tumour budding is based on epithelial-mesenchymal transition and tumour microenvironment factors and is presumed to be an early step in the metastatic process.Breast cancer tumour budding still needs multi-centre experiments. We summarize the current research on breast cancer tumour budding, analyse the method of discriminating breast cancer tumour budding and explore the prognostic role and mechanism in breast cancer.

TRAF4 Inhibits Bladder Cancer Progression by Promoting BMP/SMAD Signaling

Patients with bladder cancer often have a poor prognosis due to the highly invasive and metastatic characteristics of bladder cancer cells. Epithelial-to-mesenchymal transition (EMT) has been causally linked to bladder cancer invasion. The E3 ubiquitin ligase, tumor necrosis factor receptor-associated factor 4 (TRAF4) has been implicated as a tumor promoter in a wide range of cancers. In contrast, here we show that low TRAF4 expression is associated with poor overall survival in patients with bladder cancer. We show that the TRAF4 gene is epigenetically silenced and that ERK mediates TRAF4 phosphorylation, resulting in lower TRAF4 protein levels in bladder cancer cells. In addition, we demonstrate that TRAF4 is inversely correlated with an EMT gene signature/protein marker expression. Functionally, by manipulating TRAF4 expression, we show that TRAF4 regulates EMT genes and epithelial and invasive properties in bladder cancer cells. Transcriptomic analysis of dysregulated TRAF4 expression in bladder cancer cell lines revealed that high TRAF4 expression enhances the bone morphogenetic protein (BMP)/SMAD and inhibits the NF-κB signaling pathway. Mechanistically, we show that TRAF4 targets the E3 ubiquitin ligase SMURF1, a negative regulator of BMP/SMAD signaling, for proteasomal degradation in bladder cancer cells. This was corroborated in patient samples where TRAF4 positively correlates with phospho-SMAD1/5, and negatively correlates with phospho-NFκb-p65. Lastly, we show that genetic and pharmacologic inhibition of SMURF1 inhibits the migration of aggressive mesenchymal bladder cancer cells.

IMPLICATIONS

Our findings identify E3 ubiquitin ligase TRAF4 as a potential therapeutic target or biomarker for bladder cancer progression.

Significance of combined TGF‑β1 and survivin expression on the prognosis of patients with triple‑negative breast cancer

Compared with other types of breast cancer, triple-negative breast cancer (TNBC) has the characteristics of rapid progression, a lack of specific molecular targets for treatment and a poor prognosis. However, based on previously published studies, TGF-β1 and survivin are potentially meaningful for the prognosis of patients with TNBC. The present study was therefore designed to measure and compare the expression of transforming growth factor-β1 (TGF-β1) and survivin in tissue samples of TNBC and non-TNBC patients in order to evaluate their ability as prognostic indicators. In total, 90 TNBC and 52 non-TNBC tissue specimens were selected, following which immunohistochemistry was used to detect the expression of TGF-β1 and survivin in the cancer tissues. Subsequently, the potential association between the expression levels of these two proteins and the clinicopathological variables was analyzed. The expression levels of TGF-β1 and survivin in TNBC tissues were found to be significantly higher compared with those in the non-TNBC tissues. In addition, the results of the present study demonstrated that TGF-β1 expression was positively associated with survivin expression in the TNBC samples, but no significant correlation was found between TGF-β1 and survivin expression in the non-TNBC samples. Kaplan-Meier (K-M) analysis was performed to assess the levels of TGF-β1 and survivin in regard to patient survival, and univariate and multivariate Cox analyses of TGF-β1 and survivin protein expression were performed to analyze the overall survival (OS) and progression-free survival (PFS) rates of patients with TNBC and non-TNBC. Although multivariate Cox analysis demonstrated that neither TGF-β1 or survivin were independent prognostic predictors of TNBC or non-TNBC, results of the K-M curve revealed that patients with TNBC with TGF-β1- and survivin-positive breast cancer exhibited shorter OS and PFS times. Multivariate Cox analysis demonstrated that in patients with TNBC, the combined expression of TGF-β1 and survivin may yield additional prognostic information, compared with patients with non-TNBC.

Anti-Metastatic Function of Extracellular Vesicles Derived from Nanog-Overexpressing Melanoma

A metastatic melanoma cell line B16-F10 (F10) was modified to a more undifferentiated state by Nanog overexpression. The produced cell line Nanog⁺F10 showed a higher metastatic potential than F10. Instead of whole cells, the extracellular vesicles (EVs) therefrom were investigated about their possible role as an autovaccine against metastasis. EVs from Nanog⁺F10 cells (Nanog⁺F10-EVs) could suppress the metastasis, contrasting the EVs from less metastatic F10 cells (F10-EVs) enhanced metastasis. The involvement of TGF-β1 in the role of Nanog⁺F10-EVs was analyzed, as TGF-β1 was a secretory cytokine being affected most intensively by Nanog overexpression. It was suggested to be crucial that the TGF-β1 concentration in Nanog⁺F10-EVs should be as low as 1.6 pg/μg for its metastasis-suppressive role. In response to Nanog⁺F10-EVs, immunoreaction was observed in liver, indicating the specific decrease in the number of tumor-promotive CD163-positive macrophages. These indicate a possibility of Nanog⁺F10-EVs as a novel autovaccine candidate against melanoma metastasis.

Interleukin-6 Induced Proliferation Is Attenuated by Transforming Growth Factor-β-Induced Signaling in Human Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is often associated with an inflammatory setting. A plethora of cytokines are secreted in this milieu, actively contributing to the progression of the disease; however, the extent of cytokine interaction and how it contributes to HCC development remains an enigma. In this regard, our analysis of available patient-derived data suggests that cytokines like interleukin-6 (IL-6) and transforming growth factor-beta (TGF-β) are enriched in HCC. We further analyzed the effect of these cytokines independently or in combination on HCC cells. Importantly, IL-6 was found to induce a STAT-3-dependent proliferation and mediate its pro-proliferative effects through activation and direct interaction with the p65 subunit of NFkB. Alternatively, TGF-β was found to induce a SMAD-dependent induction of epithelial to mesenchymal transition (EMT) coupled to growth arrest in these cells. Interestingly, the simultaneous addition of IL-6 and TGF-β failed to profoundly impact EMT markers but resulted in attenuation of IL-6-induced pro-proliferative effects. Analysis of the putative molecular mechanism revealed a decrease in IL-6 receptor (IL-6R) transcript levels, reduced expression of IL-6-induced STAT-3, and its nuclear localization upon addition of TGF-β along with IL-6. Consequently, a reduced p65 activation was also observed in combination treatment. Importantly, SMAD levels were unperturbed and the cells showed more TGF-β-like features under combination treatment. Finally, we observed that TGF-β resulted in enrichment of repressive chromatin mark (H3K27me3) coupled to growth arrest, while IL-6 induced an open chromatin signature (H3K4me3) associated with an enhanced expression of EZH2. Overall, for the first time, we show that TGF-β attenuates IL-6-induced effects by regulating the receptor level, downstream signaling, and the epigenome. Understanding the complex interactions between these cytokines can be imperative to a better understanding of the disease, and manipulation of cytokine balance can act as a prospective future therapeutic strategy.

Histone deacetylase inhibition by suberoylanilide hydroxamic acid: a therapeutic approach to treat human uterine leiomyoma

OBJECTIVE

To evaluate the effect of inhibition of histone deacetylases (HDACs) by suberoylanilide hydroxamic acid (SAHA) treatment of human uterine leiomyoma primary (HULP) cells in vitro on cell proliferation, cell cycle, extracellular matrix (ECM) formation, and transforming growth factor β3 (TGF-β3) signaling.

DESIGN

Prospective study comparing uterine leiomyoma (UL) vs. adjacent myometrium (MM) tissue and cells with or without SAHA treatment.

SETTING

Hospital and university laboratories.

PATIENT(S)

Women with UL without any hormone treatment.

INTERVENTION(S)

Myomectomy or hysterectomy surgery in women for leiomyoma disease.

MAIN OUTCOME MEASURE(S)

HDAC activity was assessed by enzyme-linked immunosorbent assay, and gene expression was assessed by quantitative real-time polymerase chain reaction. Effects of SAHA on HULP cells were analyzed by CellTiter (Promega, Madison, Wisconsin), Western blot, and quantitative real-time polymerase chain reaction.

RESULT(S)

The expression of HDAC genes (HDAC1, fold change [FC] = 1.65; HDAC3, FC = 2.08; HDAC6, FC = 2.42) and activity (0.56 vs. 0.10 optical density [OD]/h/mg) was significantly increased in UL vs. MM tissue. SAHA decreased HDAC activity in HULP cells but not in MM cells. Cell viability significantly decreased in HULP cells (81.68% at 5 μM SAHA, 73.46% at 10 μM SAHA), but not in MM cells. Proliferating cell nuclear antigen expression was significantly inhibited in SAHA-treated HULP cells (5 μM SAHA, FC = 0.556; 10 μM SAHA, FC = 0.622). Cell cycle markers, including C-MYC (5 μM SAHA, FC = 0.828) and CCND1 (5 μM SAHA, FC = 0.583; 10 μM SAHA, FC = 0.482), were significantly down-regulated after SAHA treatment. SAHA significantly inhibited ECM protein expression, including FIBRONECTIN (5 μM SAHA, FC = 0.815; 10 μM SAHA, FC = 0.673) and COLLAGEN I (5 μM SAHA, FC = 0.599; 10 μM SAHA, FC = 0.635), in HULP cells. TGFβ3 and MMP9 gene expression was also significantly down-regulated by 10 μM SAHA (TGFβ3, FC = 0.596; MMP9, FC = 0.677).

CONCLUSION(S)

SAHA treatment inhibits cell proliferation, cell cycle, ECM formation, and TGF-β3 signaling in HULP cells, suggesting that histone deacetylation may be useful for treatment of UL.

MKL1 regulates hepatocellular carcinoma cell proliferation, migration and apoptosis via the COMPASS complex and NF-κB signaling

Background

Histone modification plays essential roles in hepatocellular carcinoma (HCC) pathogenesis, but the regulatory mechanisms remain poorly understood. In this study, we aimed to analyze the roles of Megakaryoblastic leukemia 1 (MKL1) and its regulation of COMPASS (complex of proteins associated with Set1) in HCC cells.

Methods

MKL1 expression in clinical tissues and cell lines were detected by bioinformatics, qRT-PCR and western blot. MKL1 expression in HCC cells were silenced with siRNA, followed by cell proliferation evaluation via Edu staining and colony formation, migration and invasion using the Transwell system, and apoptosis by Hoechst staining. HCC cell tumorigenesis was assessed by cancer cell line-based xenograft model, combined with H&E staining and IHC assays.

Results

MKL1 expression was elevated in HCC cells and clinical tissues which was correlated with poor prognosis. MKL1 silencing significantly repressed proliferation, migration, invasion and colony formation but enhanced apoptosis in HepG2 and Huh-7 cells. MKL1 silencing also inhibited COMPASS components and p65 protein expression in HepG2 and Huh-7 cells. HepG2 cell tumorigenesis in nude mice was severely impaired by MKL1 knockdown, resulted into suppressed Ki67 expression and cell proliferation.

Conclusion

MKL1 promotes HCC pathogenesis by regulating hepatic cell proliferation, migration and apoptosis via the COMPASS complex and NF-κB signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08185-w.

Molecular epigenetic dynamics in breast carcinogenesis

Breast cancer has become one of the most common dreadful diseases that target women across the globe. The most obvious reasons we associate with it are either genetic mutations or dysregulation of pathways. However, there is yet another domain that has a significant role in influencing the genetic mutations and pathways. Epigenetic mechanisms influence these pathways either independently or in association with genetic mutations, thereby expediting the process of breast carcinogenesis. Breast cancer is governed by various transduction pathways such as PI3K/AKT/mTOR, NOTCH, β Catenin, NF-kB, Hedgehog, etc. There are many proteins as well that serve to be tumor suppressors but somehow lose their ability to function. This may be because of either genetic mutation or a process that represses their function. Apart from these, there are a lot of individual factors like puberty, breastfeeding, abortion, parity, circadian rhythm, alcohol consumption, pollutants, and obesity that drive these mutations and hence alter the pathways. Epigenetic mechanisms like DNA methylation, histone modifications, and lncRNAs directly or indirectly bring alterations in the proteins that are involved in the pathways. They do this by either promoting the transcription of genes or by repressing it at the ground genetic level that advances breast carcinogenesis. Epigenetics precedes genetic mutation in driving carcinogenesis and so, it needs to be explored further to diversify the possibilities of target specific treatments. In this review, the general role of DNA methylation, histone modification, and lncRNAs in breast cancer and their role in influencing the oncogenic signaling pathways along with the various factors governing them have been discussed for a better understanding of the role of epigenetics in breast carcinogenesis.

miR-381-3p suppresses breast cancer progression by inhibition of epithelial-mesenchymal transition

Background

Accumulating evidence indicates that miRNAs are involved in multiple cellular functions and participate in various cancer development and progression, including breast cancer.

Methods

We aimed to investigate the role of miR-381-3p in breast cancer. The expression level of miR-381-3p and EMT transcription factors was examined by quantitative real-time PCR (qRT-PCR). The effects of miR-381-3p on breast cancer proliferation and invasion were determined by Cell Counting Kit-8 (CCK-8), colony formation, and transwell assays. The regulation of miR-381-3p on its targets was determined by dual-luciferase analysis, qRT-PCR, and western blot.

Results

We found that the expression of miR-381-3p was significantly decreased in breast cancer tissues and cell lines. Overexpression of miR-381-3p inhibited breast cancer proliferation and invasion, whereas knockdown of miR-381-3p promoted cell proliferation and invasion in MDA-MB-231 and SKBR3 cells. Mechanistically, overexpression of miR-381-3p inhibited breast cancer epithelial–mesenchymal transition (EMT). Both Sox4 and Twist1 were confirmed as targets of miR-381-3p. Moreover, transforming growth factor-β (TGF-β) could reverse the effects of miR-381-3p on breast cancer progression.

Conclusions

Our observation suggests that miR-381-3p inhibits breast cancer progression and EMT by regulating the TGF-β signaling via targeting Sox4 and Twist1.

Epigenetic Regulation of Breast Cancer Stem Cells Contributing to Carcinogenesis and Therapeutic Implications

Globally, breast cancer has remained the most commonly diagnosed cancer and the leading cause of cancer death among women. Breast cancer is a highly heterogeneous and phenotypically diverse group of diseases, which require different selection of treatments. Breast cancer stem cells (BCSCs), a small subset of cancer cells with stem cell-like properties, play essential roles in breast cancer progression, recurrence, metastasis, chemoresistance and treatments. Epigenetics is defined as inheritable changes in gene expression without alteration in DNA sequence. Epigenetic regulation includes DNA methylation and demethylation, as well as histone modifications. Aberrant epigenetic regulation results in carcinogenesis. In this review, the mechanism of epigenetic regulation involved in carcinogenesis, therapeutic resistance and metastasis of BCSCs will be discussed, and finally, the therapies targeting these biomarkers will be presented.

Epigenetically Mediated Ciliogenesis and Cell Cycle Regulation, and Their Translational Potential

Primary cilia biogenesis has been closely associated with cell cycle progression. Cilia assemble when cells exit the cell cycle and enter a quiescent stage at the post-mitosis phase, and disassemble before cells re-enter a new cell cycle. Studies have focused on how the cell cycle coordinates with the cilia assembly/disassembly process, and whether and how cilia biogenesis affects the cell cycle. Appropriate regulation of the functions and/or expressions of ciliary and cell-cycle-associated proteins is pivotal to maintaining bodily homeostasis. Epigenetic mechanisms, including DNA methylation and histone/chromatin modifications, are involved in the regulation of cell cycle progression and cilia biogenesis. In this review, first, we discuss how epigenetic mechanisms regulate cell cycle progression and cilia biogenesis through the regulation of DNA methylation and chromatin structures, to either promote or repress the transcription of genes associated with those processes and the modification of cytoskeleton network, including microtubule and actin. Next, we discuss the crosstalk between the cell cycle and ciliogenesis, and the involvement of epigenetic regulators in this process. In addition, we discuss cilia-dependent signaling pathways in cell cycle regulation. Understanding the mechanisms of how epigenetic regulators contribute to abnormal cell cycle regulation and ciliogenesis defects would lead to developing therapeutic strategies for the treatment of a wide variety of diseases, such as cancers, polycystic kidney disease (PKD), and other ciliopathy-associated disorders.

Association of mammographic density with blood DNA methylation

Background: Altered DNA methylation may be an intermediate phenotype between breast cancer risk factors and disease. Mammographic density is a strong risk factor for breast cancer. However, no studies to date have identified an epigenetic signature of mammographic density. We performed an epigenome-wide association study of mammographic density.

Methods: White blood cell DNA methylation was measured for 385 postmenopausal women using the Illumina Infinium MethylationEPIC BeadChip array. Differential methylation was assessed using genome-wide, probe-level, and regional analyses. We implemented a resampling-based approach to improve the stability of our findings.

Results: On average, women with elevated mammographic density exhibited DNA hypermethylation within CpG islands and gene promoters compared to women with lower mammographic density. We identified 250 CpG sites for which DNA methylation was significantly associated with mammographic density. The top sites were located within genes associated with cancer, including HDLBP, TGFB2, CCT4, and PAX8, and were more likely to be located in regulatory regions of the genome. We also identified differential DNA methylation in 37 regions, including within the promoters of PAX8 and PF4, a gene involved in the regulation of angiogenesis. Overall, our results paint a picture of epigenetic dysregulation associated with mammographic density.

Conclusion: Mammographic density is associated with differential DNA methylation throughout the genome, including within genes associated with cancer. Our results suggest the potential involvement of several genes in the biological mechanisms behind differences in breast density between women. Further studies are warranted to explore these potential mechanisms and potential links to breast cancer risk.

The lncRNA ADAMTS9-AS2 Regulates RPL22 to Modulate TNBC Progression via Controlling the TGF-β Signaling Pathway

Background

Long non-coding RNAs (lncRNAs) are key regulators of triple-negative breast cancer (TNBC) progression, but further work is needed to fully understand the functional relevance of these non-coding RNAs in this cancer type. Herein, we explored the functional role of the lncRNA ADAMTS9-AS2 in TNBC.

Methods

Next-generation sequencing was conducted to compare the expression of different lncRNAs in TNBC tumor and paracancerous tissues, after which ADAMTS9-AS2differential expression in these tumor tissues was evaluated via qPCR. The functional role of this lncRNA was assessed by overexpressing it in vitro and in vivo. FISH and PCR were used to assess the localization of ADAMTS9-AS2within cells. Downstream targets of ADAMTS9-AS2 signaling were identified via RNA pulldown assays and transcriptomic sequencing.

Results

The expression ofADAMTS9-AS2 was decreased in TNBC tumor samples (P < 0.05), with such downregulation being correlated with TNM stage, age, and tumor size. Overexpressing ADAMTS9-AS2 promoted the apoptotic death and cell cycle arrest of tumor cells in vitro and inhibited tumor growth in vivo. From a mechanistic perspective, ADAMTS9-AS2 was found to control the expression of RPL22 and to thereby modulate TGF-β signaling to control TNBC progression.

Conclusion

ADAMTS9-AS2 controls the expression of RPL22 and thereby regulates TNBC malignancy via the TGF-β signaling pathway.

Cancer drug resistance induced by EMT: novel therapeutic strategies

Over the last decade, important clinical benefits have been achieved in cancer patients by using drug-targeting strategies. Nevertheless, drug resistance is still a major problem in most cancer therapies. Epithelial-mesenchymal plasticity (EMP) and tumour microenvironment have been described as limiting factors for effective treatment in many cancer types. Moreover, epithelial-to-mesenchymal transition (EMT) has also been associated with therapy resistance in many different preclinical models, although limited evidence has been obtained from clinical studies and clinical samples. In this review, we particularly deepen into the mechanisms of which intermediate epithelial/mesenchymal (E/M) states and its interconnection to microenvironment influence therapy resistance. We also describe how the use of bioinformatics and pharmacogenomics will help to figure out the biological impact of the EMT on drug resistance and to develop novel pharmacological approaches in the future.

Thrombospondin-4 mediates hyperglycemia- and TGF-beta-induced inflammation in breast cancer

Inflammation drives the growth of tumors and is an important predictor of cancer aggressiveness. CD68, a marker of tumor-associated macrophages (TAM), is routinely used to aid in prognosis and treatment choices for breast cancer patients. We report that thrombospondin-4 (TSP-4) mediates breast cancer inflammation and growth in mouse models in response to hyperglycemia and TGF-beta by increasing TAM infiltration and production of inflammatory signals in tumors. Analysis of breast cancers and noncancerous tissue specimens from hyperglycemic patients revealed that levels of TSP-4 and of macrophage marker CD68 are upregulated in diabetic tissues. TSP-4 was colocalized with macrophages in cancer tissues. Bone-marrow-derived macrophages (BMDM) responded to high glucose and TGF-beta by upregulating TSP-4 production and expression, as well as the expression of inflammatory markers. We report a novel function for TSP-4 in breast cancer: regulation of TAM infiltration and inflammation. The results of our study provide new insights into regulation of cancer growth by hyperglycemia and TGF-beta and suggest TSP-4 as a potential therapeutic target.

The Crosstalk Between Tumor Cells and the Immune Microenvironment in Breast Cancer: Implications for Immunotherapy

Breast cancer progression is a complex process controlled by genetic and epigenetic factors that coordinate the crosstalk between tumor cells and the components of tumor microenvironment (TME). Among those, the immune cells play a dual role during cancer onset and progression, as they can protect from tumor progression by killing immunogenic neoplastic cells, but in the meanwhile can also shape tumor immunogenicity, contributing to tumor escape. The complex interplay between cancer and the immune TME influences the outcome of immunotherapy and of many other anti-cancer therapies. Herein, we present an updated view of the pro- and anti-tumor activities of the main immune cell populations present in breast TME, such as T and NK cells, myeloid cells, innate lymphoid cells, mast cells and eosinophils, and of the underlying cytokine-, cell–cell contact- and microvesicle-based mechanisms. Moreover, current and novel therapeutic options that can revert the immunosuppressive activity of breast TME will be discussed. To this end, clinical trials assessing the efficacy of CAR-T and CAR-NK cells, cancer vaccination, immunogenic cell death-inducing chemotherapy, DNA methyl transferase and histone deacetylase inhibitors, cytokines or their inhibitors and other immunotherapies in breast cancer patients will be reviewed. The knowledge of the complex interplay that elapses between tumor and immune cells, and of the experimental therapies targeting it, would help to develop new combination treatments able to overcome tumor immune evasion mechanisms and optimize clinical benefit of current immunotherapies.

USP1-WDR48 deubiquitinase complex enhances TGF-β induced epithelial-mesenchymal transition of TNBC cells via stabilizing TAK1

Triple-negative breast cancer (TNBC) is the most aggressive histological subtype of breast cancer and is characterized by poor outcomes and a lack of specific-targeted therapies. Transforming growth factor-β (TGF-β) acts as the key cytokine in the epithelial-mesenchymal transition (EMT) and the metastasis of TNBC. However, the regulatory mechanisms of the TGF-β signaling pathway remain largely unknown. In this study, we identified that the USP1/WDR48 complex could effectively enhance TGF-β-mediated EMT and migration of TNBC cells. Furthermore, lower phosphorylation of Smad2/3, Erk, Jnk, and p38 was noted on the suppression of the expression of endogenous USP1 or WDR48. Moreover, the USP1-WDR48 complex was found to downregulate the polyubiquitination of TAK1 and mediate its in vitro stability. Therefore, our findings have shed a light on the novel role of the USP1/WDR48 complex in promoting TGF-β-induced EMT and migration in TNBC via in vitro stabilization of TAK1.

Breast cancer stem cells: A review of their characteristics and the agents that affect them

The evolving concept that cancer stem cells (CSCs) are the driving element in cancer development, evolution and heterogeneity, has overridden the previous model of a tumor consisting of cells all with similar sequentially acquired mutations and a similar potential for renewal, invasion and metastasis. This paradigm shift has focused attention on therapeutically targeting CSCs directly as a means of eradicating the disease. In breast cancers, CSCs can be identified by cell surface markers and are characterized by their ability to self-renew and differentiate, resist chemotherapy and radiation, and initiate new tumors upon serial transplantation in xenografted mice. These functional properties of CSCs are regulated by both intracellular and extracellular factors including pluripotency-related transcription factors, intracellular signaling pathways and external stimuli. Several classes of natural products and synthesized compounds have been studied to target these regulatory elements and force CSCs to lose stemness and/or terminally differentiate and thereby achieve a therapeutic effect. However, realization of an effective treatment for breast cancers, focused on the biological effects of these agents on breast CSCs, their functions and signaling, has not yet been achieved. In this review, we delineate the intrinsic and extrinsic factors identified to date that control or promote stemness in breast CSCs and provide a comprehensive compilation of potential agents that have been studied to target breast CSCs, transcription factors and stemness-related signaling. Our aim is to stimulate further study of these agents that could become the basis for their use as stand-alone treatments or components of combination therapies effective against breast cancers.

Hepatocyte nuclear factor 4α and cancer-related cell signaling pathways: a promising insight into cancer treatment

Hepatocyte nuclear factor 4α (HNF4α), a member of the nuclear receptor superfamily, is described as a protein that binds to the promoters of specific genes. It controls the expression of functional genes and is also involved in the regulation of numerous cellular processes. A large number of studies have demonstrated that HNF4α is involved in many human malignancies. Abnormal expression of HNF4α is emerging as a critical factor in cancer cell proliferation, apoptosis, invasion, dedifferentiation, and metastasis. In this review, we present emerging insights into the roles of HNF4α in the occurrence, progression, and treatment of cancer; reveal various mechanisms of HNF4α in cancer (e.g., the Wnt/β-catenin, nuclear factor-κB, signal transducer and activator of transcription 3, and transforming growth factor β signaling pathways); and highlight potential clinical uses of HNF4α as a biomarker and therapeutic target for cancer.

The Small GTPase RAC1B: A Potent Negative Regulator of-and Useful Tool to Study-TGFβ Signaling

RAC1 and its alternatively spliced isoform, RAC1B, are members of the Rho family of GTPases. Both isoforms are involved in the regulation of actin cytoskeleton remodeling, cell motility, cell proliferation, and epithelial-mesenchymal transition (EMT). Compared to RAC1, RAC1B exhibits a number of distinctive features with respect to tissue distribution, downstream signaling and a role in disease conditions like inflammation and cancer. The subcellular locations and interaction partners of RAC1 and RAC1B vary depending on their activation state, which makes RAC1 and RAC1B ideal candidates to establish cross-talk with cancer-associated signaling pathways-for instance, interactions with signaling by transforming growth factor β (TGFβ), a known tumor promoter. Although RAC1 has been found to promote TGFβ-driven tumor progression, recent observations in pancreatic carcinoma cells surprisingly revealed that RAC1B confers anti-oncogenic properties, i.e., through inhibiting TGFβ-induced EMT. Since then, an unexpected array of mechanisms through which RAC1B cross-talks with TGFβ signaling has been demonstrated. However, rather than being uniformly inhibitory, RAC1B interacts with TGFβ signaling in a way that results in the selective blockade of tumor-promoting pathways, while concomitantly allowing tumor-suppressive pathways to proceed. In this review article, we are going to discuss the specific interactions between RAC1B and TGFβ signaling, which occur at multiple levels and include various components such as ligands, receptors, cytosolic mediators, transcription factors, and extracellular inhibitors of TGFβ ligands.

Identification of oncolytic vaccinia restriction factors in canine high-grade mammary tumor cells using single-cell transcriptomics

Mammary carcinoma, including triple-negative breast carcinomas (TNBC) are tumor-types for which human and canine pathologies are closely related at the molecular level. The efficacy of an oncolytic vaccinia virus (VV) was compared in low-passage primary carcinoma cells from TNBC versus non-TNBC. Non-TNBC cells were 28 fold more sensitive to VV than TNBC cells in which VV replication is impaired. Single-cell RNA-seq performed on two different TNBC cell samples, infected or not with VV, highlighted three distinct populations: naïve cells, bystander cells, defined as cells exposed to the virus but not infected and infected cells. The transcriptomes of these three populations showed striking variations in the modulation of pathways regulated by cytokines and growth factors. We hypothesized that the pool of genes expressed in the bystander populations was enriched in antiviral genes. Bioinformatic analysis suggested that the reduced activity of the virus was associated with a higher mesenchymal status of the cells. In addition, we demonstrated experimentally that high expression of one gene, DDIT4, is detrimental to VV production. Considering that DDIT4 is associated with a poor prognosis in various cancers including TNBC, our data highlight DDIT4 as a candidate resistance marker for oncolytic poxvirus therapy. This information could be used to design new generations of oncolytic poxviruses. Beyond the field of gene therapy, this study demonstrates that single-cell transcriptomics can be used to identify cellular factors influencing viral replication.

The identification of cellular genes influencing viral replication/propagation has been studied using hypothesis-driven approaches and/or high-throughput RNA interference screens. In the present report, we propose a methodology based on single-cell transcriptomics. We have studied, in the context of oncolytic virotherapy, the susceptibility of different grades of primary low-passage mammary carcinoma cells of canine origin to an oncolytic vaccinia virus (VV). We highlight a fault in replication of VV in cells that originated from high-grade triple-negative breast carcinomas (TNBC). Single-cell RNA-seq performed on TNBC cell samples infected with VV suggested that the reduced activity of the virus was associated with a higher mesenchymal status of the cells. We also demonstrate that high expression of one gene, DDIT4, is detrimental to VV production. Considering that DDIT4 is associated with a poor prognosis in various cancers including TNBC, our data highlight DDIT4 as a candidate resistance marker for oncolytic poxvirus therapy. Beyond the field of cancer gene therapy, we demonstrate here that single-cell transcriptomics increases the arsenal of tools available to identify cellular factors influencing viral replication.

Cancer-Associated Fibroblasts: Epigenetic Regulation and Therapeutic Intervention in Breast Cancer

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Cancer-associated fibroblasts (CAFs) are a heterogeneous population of cells in the solid tumour microenvironment. These cells are positively linked to breast cancer progression. Breast CAFs can be categorised into distinct subtypes according to their roles in breast carcinogenesis. Epigenetic modifications change gene expression patterns as a consequence of altered chromatin configuration and DNA accessibility to transcriptional machinery, without affecting the primary structure of DNA. Epigenetic dysregulation in breast CAFs may enhance breast cancer cell survival and ultimately lead to therapeutic resistance. A growing body of evidence has described epigenetic modulators that target histones, DNA, and miRNA as a promising approach to treat cancer. This review aims to summarise the current findings on the mechanisms involved in the epigenetic regulation in breast CAFs and discusses the potential therapeutic strategies via targeting these factors.

Resveratrol Modulates Transforming Growth Factor-Beta (TGF-β) Signaling Pathway for Disease Therapy: A New Insight into Its Pharmacological Activities

Resveratrol (Res) is a well-known natural product that can exhibit important pharmacological activities such as antioxidant, anti-diabetes, anti-tumor, and anti-inflammatory. An evaluation of its therapeutic effects demonstrates that this naturally occurring bioactive compound can target different molecular pathways to exert its pharmacological actions. Transforming growth factor-beta (TGF-β) is an important molecular pathway that is capable of regulating different cellular mechanisms such as proliferation, migration, and angiogenesis. TGF-β has been reported to be involved in the development of disorders such as diabetes, cancer, inflammatory disorders, fibrosis, cardiovascular disorders, etc. In the present review, the relationship between Res and TGF-β has been investigated. It was noticed that Res can inhibit TGF-β to suppress the proliferation and migration of cancer cells. In addition, Res can improve fibrosis by reducing inflammation via promoting TGF-β down-regulation. Res has been reported to be also beneficial in the amelioration of diabetic complications via targeting the TGF-β signaling pathway. These topics are discussed in detail in this review to shed light on the protective effects of Res mediated via the modulation of TGF-β signaling.

TGFβ-induced metabolic reprogramming during epithelial-to-mesenchymal transition in cancer

Metastasis is the most frequent cause of death in cancer patients. Epithelial-to-mesenchymal transition (EMT) is the process in which cells lose epithelial integrity and become motile, a critical step for cancer cell invasion, drug resistance and immune evasion. The transforming growth factor-β (TGFβ) signaling pathway is a major driver of EMT. Increasing evidence demonstrates that metabolic reprogramming is a hallmark of cancer and extensive metabolic changes are observed during EMT. The aim of this review is to summarize and interconnect recent findings that illustrate how changes in glycolysis, mitochondrial, lipid and choline metabolism coincide and functionally contribute to TGFβ-induced EMT. We describe TGFβ signaling is involved in stimulating both glycolysis and mitochondrial respiration. Interestingly, the subsequent metabolic consequences for the redox state and lipid metabolism in cancer cells are found to be in favor of EMT as well. Combined we illustrate that a better understanding of the mechanistic links between TGFβ signaling, cancer metabolism and EMT holds promising strategies for cancer therapy, some of which are already actively being explored in the clinic.

EMT related circular RNA expression profiles identify circSCYL2 as a novel molecule in breast tumor metastasis

Substantial evidence indicates that circular RNAs (circRNAs) play vital roles in several diseases, especially in cancer development. However, the functions of circRNAs in breast cancer metastasis remain to be investigated. This study aimed to identify the key circRNAs involved in epithelial mesenchymal transition (EMT) of breast cancer and evaluated their molecular function and roles in pathways that may be associated with tumor metastasis. An EMT model was constructed by treating breast cancer cells MCF‑7 and MDA‑MB‑231 with transforming growth factor‑β1. High‑throughput RNA sequencing was used to identify the differentially expressed circRNAs in EMT and blank groups of two cells, and reverse transcription‑quantitative PCR was used to validate the expression of circSCYL2 in human breast cancer tissues and cells. The effects of circSCYL2 on breast cancer cells were explored by transfecting with plasmids and the biological roles were assessed using transwell assays. EMT groups of breast cancer cells exhibited the characteristics of mesenchymal cells. Furthermore, the present study found that 7 circRNAs were significantly upregulated in both the MCF‑7 EMT and MDA‑MB‑231 EMT groups, while 16 circRNAs were significantly downregulated. The current study identified that circSCYL2 was downregulated in breast cancer tissues and cell lines, and that circSCYL2 overexpression inhibited cell migration and invasion. This study provides expression profiles of circRNAs in EMT groups of breast cancer cells. circSCYL2, which is downregulated in breast cancer tissues and cells, may play an important role in breast cancer EMT progression.

ATBF1 Participates in Dual Functions of TGF-β via Regulation of Gene Expression and Protein Translocalization

TGF-β is a critical cytokine to regulate multiple pathophysiological functions. For tumor development and progression, TGF-β was reported to play dual functions as a tumor suppressor and epithelial-mesenchymal transition (EMT) inducer. The mechanism of the TGF-β signaling pathway is essential for TGF-β/Smad-targeted therapy in clinic. Here, ATBF1 was demonstrated to participate in dual functions of TGF-β via different ways. On one hand, ATBF1 expression level was associated with EMT and migration induced by TGF-β. After TGF-β treatment, ATBF1 expression was reduced in a dose- and time-dependent manner, along with the alteration of cell morphology and EMT marker expression. Knockdown of ATBF1 by siRNA further promoted EMT progression and cell migration. On the other hand, ATBF1 localization was associated with cell proliferation inhibited by TGF-β. The number of cells with nucleus localization of ATBF1 in TGF-β activation group was much higher than that in control group. After that, knockdown of ATBF1 by siRNA rescued the inhibition of cell proliferation affected by TGF-β. These data revealed that ATBF1 is a key gene for the dual roles of TGF-β, which may contribute to future therapy.

LncRNA MIR4435-2HG-mediated upregulation of TGF-β1 promotes migration and proliferation of nonsmall cell lung cancer cells

The roles of long noncoding RNAs (lncRNAs) have been shown to play critical roles in tumor progression. Here, it was identified that lncRNA MIR4435-2HG was highly expressed in lung cancer tissues, especially in nonsmall cell lung cancer (NSCLC). A consistent result was obtained in lung cancer cells. Functional experiments showed that knockdown of MIR4435-2HG reduced the proliferation and migration ability of NSCLC cells. Transcriptome-sequencing analysis indicated that TGF-β signaling was mostly enriched in NSCLC cells with MIR4435-2HG knockdown. Furthermore, MIR4435-2HG was identified as an miRNA sponge for TGF-β1 and thus activated TGF-β signaling. Additionally, re-activation of TGF-β1 rescued MIR4435-2HG knockdown-mediated inhibition on the progression of NSCLC cells. Therefore, this work indicates a novel MIR4435-2HG/TGF-β1 axis responsible for NSCLC cell progression.

Oncolytic virotherapy armed with an engineered interfering lncRNA exhibits antitumor activity by blocking the epithelial mesenchymal transition in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has special characteristics of significant aggressiveness, and strong potential for metastasis and recurrence; currently there are no targeted drugs for TNBC. Abnormal activation of epithelial-mesenchymal transition (EMT) plays an important role in these malignant behaviors of TNBC. In the crosstalk among the multiple EMT-associated signaling pathways, many miRNAs participate in regulating pathway activity, where they act as "traffic lights" at the intersection of these pathways. In this study, we used miRNA microarray technology to detect differentially expressed miRNAs related to EMT in TNBC, and we identified and verified 9 highly expressed oncogenic miRNAs (OncomiRs). High expression of these OncomiRs in clinical breast cancer tissues affected the prognosis of patients, and inhibition of their expression blocked EMT in TNBC cell lines and suppressed cancer cell proliferation and migration. We constructed an oncolytic adenovirus (AdSVP-lncRNAi9) armed with an artificially-designed interfering lncRNA (lncRNAi9), which exhibited an activity to block EMT in TNBC cells by disrupting the functions of multiple OncomiRs; the efficacy of such a treatment for TNBC was demonstrated in cytology and animal experiments. This research provides a new candidate oncolytic virotherapy for treating highly malignant refractory TNBC.

DCST1-AS1 Promotes TGF-β-Induced Epithelial-Mesenchymal Transition and Enhances Chemoresistance in Triple-Negative Breast Cancer Cells via ANXA1

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype, and the primary systemic treatment strategy involves conventional chemotherapy. DC-STAMP domain containing 1-antisense 1 (DCST1-AS1) is a long non-coding RNA that promotes TNBC migration and invasion. Studying the role of DCST1-AS1 in promoting epithelial–mesenchymal transition (EMT) and chemoresistance will provide a new strategy for TNBC therapy. In the present study, we found that DCST1-AS1 regulates the expression or secretion of EMT-related proteins E-cadherin, snail family zinc finger 1 (SNAI1), vimentin, matrix metallopeptidase 2 (MMP2), and matrix metallopeptidase 9 (MMP9). Interference with DCST1-AS1 impaired TGF-β-induced TNBC cell invasion and migration. DCST1-AS1 directly binds to ANXA1 in BT-549 cells and affects the expression of ANXA1. DCST1-AS1 enhances TGF-β/Smad signaling in BT-549 cells through ANXA1 to promote EMT. The combination of DCST1-AS1 and ANXA1 also contributes to enhancement of the resistance of BT-549 cells to doxorubicin and paclitaxel. In conclusion, DCST1-AS1 promotes TGF-β-induced EMT and enhances chemoresistance in TNBC cells through ANXA1, and therefore represents a potentially promising target for metastatic breast cancer therapy.

Effects of S‑adenosyl‑L‑methionine on the invasion and migration of head and neck squamous cancer cells and analysis of the underlying mechanisms

S-Adenosyl-L-methionine (AdoMet) is the principal methyl donor in transmethylation reactions fundamental to sustaining epigenetic modifications. Over the past decade, AdoMet has been extensively investigated for its anti- proliferative, pro-apoptotic and anti-metastatic roles in several types of human cancer. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide, and is an aggressive type of cancer that is associated with a high recurrence rate, metastasis and poor treatment outcomes. The present study demonstrates, for the first time, to the best of our knowledge, that AdoMet induces cell cycle arrest and inhibits the migratory and invasive ability of two different HNSCC cell lines, oral Cal-33 and laryngeal JHU-SCC-011 cells. In both cell lines, AdoMet attenuated cell cycle progression, decreased the protein level of several cyclins and downregulated the expression of p21 cell cycle inhibitor. Moreover, AdoMet was able to inhibit Cal-33 and JHU-SCC-011 cell migration in a dose-dependent manner after 24 and 48 h, respectively, and also induced a significant reduction in the cell invasive ability, as demonstrated by Matrigel invasion assay monitored by the xCELLigence RTCA system. Western blot analysis of several migration and invasion markers confirmed the inhibitory effects exerted by AdoMet on these processes and highlighted AKT, β-catenin and small mothers against decapentaplegic (SMAD) as the main signaling pathways modulated by AdoMet. The present study also demonstrated that the combination of AdoMet and cisplatin synergistically inhibited HNSCC cell migration. Taken together, these findings demonstrate that the physiological compound, AdoMet, affects the motility and extracellular matrix invasive capability in HNSCC. Thus, AdoMet may prove to be a good candidate for future drug development against metastatic cancer.

TGF-β1 stimulates epithelial-mesenchymal transition and cancer-associated myoepithelial cell during the progression from in situ to invasive breast cancer

Background

The progression of ductal carcinoma in situ (DCIS) into invasive ductal carcinoma (IDC) is prevented by normal breast myoepithelial cells. Studies have suggested that EMT-associated genes were enriched in IDC in contrast to DCIS. This paper explored the relationship and potential mechanism between myoepithelial cells and EMT-associated genes in facilitating the transformation from DCIS to breast cancer.

Methods

EMT markers and myoepithelial phenotypic markers in IDC, DCIS, and healthy breast tissue were characterized using immunohistochemical assay. Both in vivo and in vitro models were created to mimic the various cell–cell interactions in the development of invasive breast cancer.

Results

We found that EMT markers were more abundant in invasive carcinomas than DCIS and adjacent normal breast tissue. Meanwhile, TGF-β1 regulated the morphology of MCF-7 (epithelial cells substitute) migration and EMT markers during the transformation from DCIS to invasive breast cancer. Additionally, TGF-β1 also regulated invasion, migration and cytokines secretion of MDA-MB-231 (myoepithelial cells substitute) and epithelial cells when co-cultured with MCF-7 both in vitro and in vivo.

Conclusions

In conclusion, these findings demonstrated that both EMT phenotypes and cancer-associated myoepithelial cells may have an impact on the development of invasive breast cancer.

Osteoglycin (OGN) Inhibits Cell Proliferation and Invasiveness in Breast Cancer via PI3K/Akt/mTOR Signaling Pathway

Introduction

Previous studies have indicated that the small leucine-rich proteoglycan (SLR) osteoglycin (OGN) is downregulated in various cancers, including squamous cervical carcinoma, gastric cancer, and colorectal adenoma, indicating that OGN is a putative tumor suppressor. However, its exact role in the pathology of human cancers, especially breast cancer (BC), is not clear.

Methods

The expression of OGN in BC tissues was examined using qRT-PCR. Online databases were employed to analyze the correlation between OGN expression and clinicopathological characteristics. CCK-8 assay, colony formation assay, transwell migration and invasion assays were applied to detect cell proliferation, colony formation, migration and invasion of BC cells, respectively. Xenograft tumor models were constructed to explore the role of OGN on tumor growth in vivo.

Results

OGN expression was reduced in 24 paired BC samples compared with normal tissue. Decreased expression of OGN was correlated with greater pathological grade, a more aggressive tumor subtype, and poor overall survival. In vitro experiments showed that OGN overexpressed by plasmid transfection significantly inhibited cell proliferation, colony formation, migration, and invasion of BC cell lines. In xenograft tumor models, overexpression of OGN repressed the growth of MCF-7 cells in vivo and alleviated the compression of the tumor on surrounding structures. We also observed that OGN expression reversed EMT via repressing the PI3K/Akt/mTOR pathway.

Conclusion

This study revealed that OGN could function as a tumor suppressor during breast carcinogenesis, and we contribute new evidence to the body of research on the SLRP family.

SETDB-1: A Potential Epigenetic Regulator in Breast Cancer Metastasis

The full epigenetic repertoire governing breast cancer metastasis is not completely understood. Here, we discuss the histone methyltransferase SET Domain Bifurcated Histone Lysine Methyltransferase 1 (SETDB1) and its role in breast cancer metastasis. SETDB1 serves as an exemplar of the difficulties faced when developing therapies that not only specifically target cancer cells but also the more elusive and aggressive stem cells that contribute to metastasis via epithelial-to-mesenchymal transition and confer resistance to therapies.

Stomatin plays a suppressor role in non-small cell lung cancer metastasis

Objective

Metastasis is one of the key causes of high mortality in lung cancer. Aberrant DNA methylation is a common event in metastatic lung cancer. We aimed to identify new epigenetic regulation of metastasis-associated genes and characterize their effects on lung cancer progression.

Methods

We screened genes associated with non-small cell lung cancer (NSCLC) metastasis by integrating datasets from the Gene Expression Omnibus (GEO) database. We obtained epigenetic-regulated candidate genes by analyzing the expression profile of demethylation genes. By overlapping analysis, epigenetically modulated metastasis-associated genes were obtained. Kaplan-Meier plotter (KM plotter) was utilized to assess the overall survival (OS) of stomatin in lung cancer. Immunohistochemistry (IHC) was conducted to determine the association between stomatin and metastasis-associated clinical indicators. Both in vitro and in vivo assays were performed to investigate the potential role of stomatin in metastasis. The regulation mechanisms of transforming growth factor β1 (TGFβ1) on stomatin were determined by Sequenom MassARRAY quantitative methylation and western blot assays.

Results

A series of bioinformatic analyses revealed stomatin as the metastasis-associated gene regulated by DNA methylation. The KM plotter analysis showed a positive association between stomatin and the OS of lung cancer. IHC analysis indicated that the decreased stomatin expression is linked with advanced TNM stage. Loss- and gain-of-function experiments displayed that stomatin could inhibit the migration and invasion of NSCLC cells. Furthermore, TGFβ1 repressed stomatin expression during epithelial-to-mesenchymal transition (EMT). The negative correlation between stomatin and TGFβ1 was also validated in advanced stage III lung tumor samples. The underlying mechanism by which TGFβ1 inhibits stomatin is due in part to DNA methylation.

Conclusions

Our results suggest that stomatin may be a target for epigenetic regulation and can be used to prevent metastatic diseases.