Biomarkers for EMT and MET in breast cancer: An update

The Role of NLRP3 Inflammasome Activation in the Epithelial to Mesenchymal Transition Process During the Fibrosis

Fibrosis is considered a complex form of tissue damage commonly present in the end stage of many diseases. It is also related to a high percentage of death, whose predominant characteristics are an excessive and abnormal deposition of fibroblasts and myofibroblasts -derived extracellular matrix (ECM) components. Epithelial-to-mesenchymal transition (EMT), a process in which epithelial cells gradually change to mesenchymal ones, is a major contributor in the pathogenesis of fibrosis. The key mediator of EMT is a multifunctional cytokine called transforming growth factor-β (TGF-β) that acts as the main inducer of the ECM assembly and remodeling through the phosphorylation of Smad2/3, which ultimately forms a complex with Smad4 and translocates into the nucleus. On the other hand, the bone morphogenic protein-7 (BMP-7), a member of the TGF family, reverses EMT by directly counteracting TGF-β induced Smad-dependent cell signaling. NLRP3 (NACHT, LRR, and PYD domains-containing protein 3), in turn, acts as cytosolic sensors of microbial and self-derived molecules and forms an immune complex called inflammasome in the context of inflammatory commitments. NLRP3 inflammasome assembly is triggered by extracellular ATP, reactive oxygen species (ROS), potassium efflux, calcium misbalance, and lysosome disruption. Due to its involvement in multiple diseases, NLRP3 has become one of the most studied pattern-recognition receptors (PRRs). Nevertheless, the role of NLRP3 in fibrosis development has not been completely elucidated. In this review, we described the relation of the previously mentioned fibrosis pathway with the NLRP3 inflammasome complex formation, especially EMT-related pathways. For now, it is suggested that the EMT happens independently from the oligomerization of the whole inflammasome complex, requiring just the presence of the NLRP3 receptor and the ASC protein to trigger the EMT events, and we will present different pieces of research that give controversial point of views.

Expression of epithelial-mesenchymal transition-related markers and phenotypes during breast cancer progression

Purpose

The study aimed to investigate expression of epithelial-to-mesenchymal transition (EMT)-related proteins and phenotypes during breast cancer progression and to relate this to patient outcome.

Methods

Protein expression patterns of E-cadherin, N-cadherin, twist, and vimentin were examined by immunohistochemistry on formalin-fixed paraffin-embedded samples from primary tumors (PTs) (n = 419), synchronous lymph node metastases (LNMs) (n = 131) and recurrences (n = 34) from patients included in an observational prospective primary breast cancer study. Markers were evaluated individually and combined as defined EMT phenotypes (epithelial, mesenchymal, partial EMT, and negative). EMT profiles were compared between matched tumor progression stages, and related to clinicopathological data and distant recurrence-free interval (DRFi).

Results

N-cadherin-positivity, vimentin-positivity, mesenchymal and partial EMT phenotypes were associated with more aggressive tumor characteristics such as triple-negative subtype. Single EMT markers and phenotype discordance rates between paired tumor samples were observed in the range of 2–35%. Non-epithelial phenotypes were more frequently identified in recurrences compared to PTs, however, no skewness of expression or phenotype was detected between PTs and matched LNMs or between PTs and matched recurrences (Exact McNemar test). Interestingly, patients with a twist positive PT had shorter DRFi, compared to patients with a twist negative PT (hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.2–5.1, P = 0.02). Essentially, the same effect was seen in multivariable analysis (HR 2.5, 95% CI 0.97–6.6, P = 0.06).

Conclusion

The epithelial phenotype was indicated to be lost between PTs and recurrences as a reflection of tumor progression. Twist status of the PT was related to long-term prognosis warranting further investigation in larger cohorts.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05627-0) contains supplementary material, which is available to authorized users.

Breast cancer metastasis to bone: From epithelial to mesenchymal transition to breast osteoblast-like cells

In this review we highlighted the newest aspects concerning the physiopathology of breast cancer metastatization into the bone including: a) in situ biomarkers of breast cancer metastatic diseases, b) biological processes related to the origin of metastatic cells (epithelial to mesenchymal transition), c) the nature and the possible role of Breast Osteoblast-Like Cells in the formation of bone lesions and d) the prognostic value of breast microcalcifications for the bone metastatic disease. In addition, the more recent data about the biology of breast cancer metastatic process and the origin and function of Breast Osteoblast-Like Cells have been analyzed to propose the use of molecular imaging investigations able to identify early neoplastic lesions with high propensity to form bone metastasis in vivo.

Trichostatin A reverses epithelial-mesenchymal transition and attenuates invasion and migration in MCF-7 breast cancer cells

Breast cancer remains one of the leading causes of mortality in women, and epithelial-mesenchymal transition (EMT) serves an indispensable role in the invasion and migration of breast cancer cells. As a representative of classical histone deacetylase inhibitors (HDACIs), trichostatin A (TSA) has been demonstrated to reverse EMT in certain types of non-tumor cells and tumor cells. In the present study, the invasive and migratory abilities of MCF-7 cells were examined following treatment with TSA. TSA-induced changes in the expression of an epithelial biomarker epithelial cadherin (E-cadherin), a mesenchymal biomarker (vimentin), and a transcription factor [zinc finger protein SNAI2 (SLUG)] were also investigated. Transwell invasion and migration assays, and wound healing assays, revealed that the invasive and migratory abilities of MCF-7 cells were suppressed significantly upon treatment with TSA. Treatment with TSA led to an increased expression level of E-cadherin, and decreased expression of vimentin and, in MCF-7 cells. The overexpression of SLUG decreased the expression level of E-cadherin, but increased vimentin expression, and upon treatment with TSA, these effects were reversed. Additionally, SLUG knockdown also led to upregulation of E-cadherin expression, downregulation of vimentin expression, and suppression of the invasion and migration of MCF-7 cells. Taken together, these results suggest that TSA is able to reverse EMT via suppressing SLUG and attenuate the invasion and migration of MCF-7 cells in vitro, thereby providing a potential avenue for chemotherapeutic intervention in the treatment of breast cancer.

Single-cell RNA-sequencing of migratory breast cancer cells: discovering genes associated with cancer metastasis

Considerable evidence suggests breast cancer metastasis arises from cells undergoing epithelial-to-mesenchymal-transition (EMT) and cancer stem-like cells (CSCs). Using a microfluidic device that enriches migratory breast cancer cells with enhanced capacity for tumor formation and metastasis, we identified genes differentially expressed in migratory cells by high-throughput single-cell RNA-sequencing. Migratory cells exhibited overall signatures of EMT and CSCs with variable expression of marker genes, and they retained expression profiles of EMT over time. With single-cell resolution, we discovered intermediate EMT states and distinct epithelial and mesenchymal sub-populations of migratory cells, indicating breast cancer cells can migrate rapidly while retaining an epithelial state. Migratory cells showed differential profiles for regulators of oxidative stress, mitochondrial morphology, and the proteasome, revealing potential vulnerabilities and unexpected consequences of drugs. We also identified novel genes correlated with cell migration and outcomes in breast cancer as potential prognostic biomarkers and therapeutic targets to block migratory cells in metastasis.

Rosmarinic acid inhibits proliferation and invasion of hepatocellular carcinoma cells SMMC 7721 via PI3K/AKT/mTOR signal pathway

OBJECTIVE

To investigate the effect of rosmarinic acid (RosA) on hepatocellular carcinoma cell in vivo and in vitro and to explore its possible mechanism of anti-hepatocarcinoma.

METHODS

The hepatocellular carcinoma cell line SMMC-7721 was treated with different concentrations of RosA (0, 20, 50, 100 μmol/L) to detect cell proliferation, cell cycle, apoptosis and invasion.PI3K pathway-specific activator IGF-1 was used to explore whether the mechanism for RosA action relates to PI3K/AKT signal pathway.Nude mice inoculated with SMMC-7721 cells were treated with different doses of RosA (0, 5, 10 and 20 mg/kg) to detect the tumor formation of cancer cells in vivo.

RESULTS

RosA significantly inhibited the proliferation of SMMC-7721 cells and induced G1 arrest and apoptosis in a dose-dependent manner. RosA might inhibit cell invasion by regulating epithelial-mesenchymal transition. Rescue experiments showed that IGF-1 could reverse the inhibition of PI3K/AKT/mTOR signal pathway by RosA and the effect on proliferation, apoptosis, cell cycle, invasion and EMT by IGF-1 in SMMC-7721 cells;RosA could inhibit tumor formation of SMMC-7721 cells in vivo.

CONCLUSION

RosA can inhibit the proliferation and invasion of hepatocellular carcinoma cell in vitro and inhibit tumour growth in vivo and the mechanism may relate to inhibiting the activation of PI3K/AKT signal pathway.

Long Non-Coding RNA CASC9 And HIF-1α Form A Positive Feedback Loop To Facilitate Cell Proliferation And Metastasis In Lung Cancer

Background

The long noncoding RNA cancer susceptibility 9 (CASC9) has been recognized as an important modulator of cell growth and metastasis in many cancers. However, its detailed roles in lung cancer remain unclear. In this study, we aimed to investigate its functions and molecular mechanism in lung cancer progression.

Methods

Expression of CASC9 was determined in lung cancer tissues and cell lines by real-time PCR. CCK-8, colony formation, wound healing and transwell assays were done to evaluate the cell proliferation, migration and invasion capacities in vitro. Real-time PCR, Western blot and RNA immunoprecipitation (RIP) assays were performed to dissect the mechanisms.

Results

CASC9 was overexpressed in lung cancer specimens and cell lines. Knockdown of CASC9 inhibited cell proliferation, migration, invasion and EMT in lung cancer cells. While overexpression of CASC9 in normal lung epithelial cells did the opposite. CASC9 interacted with HIF-1α and enhanced its protein stability. They formed a positive feedback loop by reciprocally inducing each other expression and regulated cell proliferation and metastasis.

Conclusion

Our findings demonstrated a novel regulatory signaling pathway, namely the CASC9/HIF-1α axis, which was involved in lung cancer progression. These findings can provide valuable insights on the potential therapy application for lung cancer.

The Molecular Mechanism of Epithelial-Mesenchymal Transition for Breast Carcinogenesis

The transforming growth factor-β (TGF-β) signaling pathway plays multiple regulatory roles in the tumorigenesis and development of cancer. TGF-β can inhibit the growth and proliferation of epithelial cells and induce apoptosis, thereby playing a role in inhibiting breast cancer. Therefore, the loss of response in epithelial cells that leads to the inhibition of cell proliferation due to TGF-β is a landmark event in tumorigenesis. As tumors progress, TGF-β can promote tumor cell invasion, metastasis, and drug resistance. At present, the above-mentioned role of TGF-β is related to the interaction of multiple signaling pathways in the cell, which can attenuate or abolish the inhibition of proliferation and apoptosis-promoting effects of TGF-β and enhance its promotion of tumor progression. This article focuses on the molecular mechanisms through which TGF-β interacts with multiple intracellular signaling pathways in tumor progression and the effects of these interactions on tumorigenesis.

New advance in breast cancer pathology and imaging

The improvement of knowledge concerning the pathology of breast cancer could provide the rationale for the development of new imaging diagnostic protocols. Indeed, as for the microcalcifications, new histopathological markers can be used as target for in vivo early detection of breast cancer lesions by using molecular imaging techniques such as positron emission tomography. Specifically, the mutual contribution of these medical specialties can ‘nourish’ the dream of a personalized medicine that takes into account the intrinsic variability of breast cancer. In this review, we report the main discoveries concerning breast cancer pathology highlighting the possible cooperation between the departments of anatomic pathology and imaging diagnostics.

Morphology-based prediction of cancer cell migration using an artificial neural network and a random decision forest

Metastasis is the cause of death in most patients of breast cancer and other solid malignancies. Identification of cancer cells with highly migratory capability to metastasize relies on markers for epithelial-to-mesenchymal transition (EMT), a process increasing cell migration and metastasis. Marker-based approaches are limited by inconsistences among patients, types of cancer, and partial EMT states. Alternatively, we analyzed cancer cell migration behavior using computer vision. Using a microfluidic single-cell migration chip and high-content imaging, we extracted morphological features and recorded migratory direction and speed of breast cancer cells. By applying a Random Decision Forest (RDF) and an Artificial Neural Network (ANN), we achieved over 99% accuracy for cell movement direction prediction and 91% for speed prediction. Unprecedentedly, we identified highly motile cells and non-motile cells based on microscope images and a machine learning model, and pinpointed and validated morphological features determining cell migration, including not only known features related to cell polarization but also novel ones that can drive future mechanistic studies. Predicting cell movement by computer vision and machine learning establishes a ground-breaking approach to analyze cell migration and metastasis.

Class I histone deacetylase inhibitor suppresses vasculogenic mimicry by enhancing the expression of tumor suppressor and anti-angiogenesis genes in aggressive human TNBC cells

Triple-negative breast cancer (TNBC) cells form angiogenesis-independent vessel-like structures to survive, known as vasculogenic mimicry (VM), contributing to a poor prognosis for cancer patients. Nuclear localized class I histone deacetylases (HDACs) enzymes, particularly HDACs 1, 2, 3 deacetylate chromatin histones, are overexpressed in cancers and epigenetically regulate the expression of genes involved in cancer initiation and progression. The specific HDAC inhibitor, entinostat, has been shown to attenuate tumor progression and metastasis in TNBC. In this study, we hypothesized that entinostat would enhance the expression of anti-angiogenic and tumor suppressor genes and would thus suppress VM structures in TNBC cells in a 3D Matrigel cell culture preclinical model. Our data indicated that invasive triple-negative MDA-MB-231, LM2-4 and BT-549 breast cancer cells, but not poorly invasive luminal MCF-7 cells, efficiently underwent matrix-associated VM formation. Approximately 80% of TNBC cells with the stem cell phenotype potential formed vessel-like structures when mixed with Matrigel and cultured in the low attachment tissue culture plate. The molecular mechanisms of VM formation are rather complex, while angiogenesis inhibitor genes are downregulated and pro-angiogenesis genes are upregulated in VM-forming cells. Our data revealed that treatment of the TNBC VM phenotype cells with entinostat epigenetically led to the re-expression of the anti-angiogenic genes, serpin family F member 1 (SERPINF1) and thrombospondin 2 (THBS2), and to that of the tumor suppressor genes, phosphatase and tensin homolog (PTEN) and p21, and reduced VM structures. We also found that treatment of the TNBC VM phenotype cells with entinostat downregulated the expression of vascular endothelial growth factor A (VEGF-A), and that of the epithelial-mesenchymal transition (EMT)-related genes, Vimentin and β-catenin. METABIRC and TCGA breast cancer cohort mRNA expression data analysis revealed that a high expression of the anti-angiogenesis-associated genes, THBS2, SERPINF1 and serpin family B member 5 (SERPINB5), and of the tumor suppressor gene, PTEN, was associated with a better overall survival (OS) of breast cancer patients. Taken together, the findings of this study demonstrate that HDACs 1, 2, 3 partly contribute to VM formation in TNBC cells; thus, HDACs may be an important therapeutic target for TNBC.

P-cadherin mutations are associated with high basal Wnt activity and stemness in canine mammary tumor cell lines

Purpose: To find underlying mutations causing highly-activated Wnt activity in mammary tumor cell lines associated with rounded morphology indicative of stemness/EMT. Methods: Stemness of high Wnt cell lines was confirmed using qPCR on selected genes and microRNA profiling, followed by whole-exome sequencing of 3 high Wnt canine mammary tumor cell lines and 5 low/absent Wnt cell lines. Candidate genes were identified and their involvement in Wnt activity investigated using siRNA silencing. Results: The high Wnt cell lines had morphological and gene expression characteristics reminiscent of stemness. All individual cell lines had about 4000 mutations in the exome in comparison to the reference canine genome. The three high basal Wnt cell lines had 167 unique exome mutations. Seven of these mutations resulted in a SIFT score <0.2 of proteins related to Wnt signaling. However, gene silencing did not change the Wnt pathway activation. Renewed analysis with respect to putative relations to Wnt signaling revealed that P-cadherin (CDH3) had three mutations in the coding region of the extracellular domain and was associated with high Wnt signaling. Silencing by siRNA not only in lowered Wnt activity, but also decreased levels of phosphorylated cSRC and sP-cad, and changed cell morphology towards spindle cell appearance. Conclusion: It is concluded that expression of mutated CDH3 is associated with activation of cSRC, stabilization of ß-catenin and a rounded morphology related to a stemness/EMT phenotype. A decreased Wnt activity can be found also by cSRC inhibition, but CDH3 silencing has an additional effect on morphology indicating reversal of EMT.

Development and characterisation of acquired radioresistant breast cancer cell lines

BACKGROUND

Radiotherapy plays an important role in the multimodal treatment of breast cancer. The response of a breast tumour to radiation depends not only on its innate radiosensitivity but also on tumour repopulation by cells that have developed radioresistance. Development of effective cancer treatments will require further molecular dissection of the processes that contribute to resistance.

METHODS

Radioresistant cell lines were established by exposing MDA-MB-231, MCF-7 and ZR-751 parental cells to increasing weekly doses of radiation. The development of radioresistance was evaluated through proliferation and colony formation assays. Phenotypic characterisation included migration and invasion assays and immunohistochemistry. Transcriptomic data were also generated for preliminary hypothesis generation involving pathway-focused analyses.

RESULTS

Proliferation and colony formation assays confirmed radioresistance. Radioresistant cells exhibited enhanced migration and invasion, with evidence of epithelial-to-mesenchymal-transition. Significantly, acquisition of radioresistance in MCF-7 and ZR-751 cell lines resulted in a loss of expression of both ERα and PgR and an increase in EGFR expression; based on transcriptomic data they changed subtype classification from their parental luminal A to HER2-overexpressing (MCF-7 RR) and normal-like (ZR-751 RR) subtypes, indicating the extent of phenotypic changes and cellular plasticity involved in this process. Radioresistant cell lines derived from ER+ cells also showed a shift from ER to EGFR signalling pathways with increased MAPK and PI3K activity.

CONCLUSIONS

This is the first study to date that extensively describes the development and characterisation of three novel radioresistant breast cancer cell lines through both genetic and phenotypic analysis. More changes were identified between parental cells and their radioresistant derivatives in the ER+ (MCF-7 and ZR-751) compared with the ER- cell line (MDA-MB-231) model; however, multiple and likely interrelated mechanisms were identified that may contribute to the development of acquired resistance to radiotherapy.

Atypical plant homeodomain of UBR7 functions as an H2BK120Ub ligase and breast tumor suppressor

The roles of Plant Homeodomain (PHD) fingers in catalysis of histone modifications are unknown. We demonstrated that the PHD finger of Ubiquitin Protein Ligase E3 Component N-Recognin7 (UBR7) harbors E3 ubiquitin ligase activity toward monoubiquitination of histone H2B at lysine120 (H2BK120Ub). Purified PHD finger or full-length UBR7 monoubiquitinated H2BK120 in vitro, and loss of UBR7 drastically reduced H2BK120Ub genome-wide binding sites in MCF10A cells. Low UBR7 expression was correlated with occurrence of triple-negative breast cancer and metastatic tumors. Consistently, UBR7 knockdown enhanced the invasiveness, induced epithelial-to-mesenchymal transition and promoted metastasis. Conversely, ectopic expression of UBR7 restored these cellular phenotypes and reduced tumor growth. Mechanistically, UBR7 loss reduced H2BK120Ub levels on cell adhesion genes, including CDH4, and upregulated the Wnt/β-Catenin signaling pathway. CDH4 overexpression could partially revert UBR7-dependent cellular phenotypes. Collectively, our results established UBR7 as a histone H2B monoubiquitin ligase that suppresses tumorigenesis and metastasis of triple-negative breast cancer.

hnRNP E1 at the crossroads of translational regulation of epithelial-mesenchymal transition

The epithelial-mesenchymal transition (EMT), in which cells undergo a switch from a polarized, epithelial phenotype to a highly motile fibroblastic or mesenchymal phenotype is fundamental during embryonic development and can be reactivated in a variety of diseases including cancer. Spatio-temporally-regulated mechanisms are constantly orchestrated to allow cells to adapt to their constantly changing environments when disseminating to distant organs. Although numerous transcriptional regulatory factors are currently well-characterized, the post-transcriptional control of EMT requires continued investigation. The hnRNP E1 protein displays a major role in the control of tumor cell plasticity by regulating the translatome through multiple non-redundant mechanisms, and this role is exemplified when E1 is absent. hnRNP E1 binding to RNA molecules leads to direct or indirect translational regulation of specific sets of proteins: (1) hnRNP E1 binding to specific targets has a direct role in translation by preventing elongation of translation; (2) hnRNP E1-dependent alternative splicing can prevent the generation of a competing long non-coding RNA that acts as a decoy for microRNAs (miRNAs) involved in translational inhibition of EMT master regulators; (3) hnRNP E1 binding to the 3’ untranslated region of transcripts can also positively regulate the stability of certain mRNAs to improve their translation. Globally, hnRNP E1 appears to control proteome reprogramming during cell plasticity, either by direct or indirect regulation of protein translation.

CD147 mediates transforming growth factor-β1-induced epithelial-mesenchymal transition and cell invasion in squamous cell carcinoma of the tongue

Epithelial-mesenchymal transition (EMT) is a physiological process in which epithelial cells attain the motile and invasive characteristics of mesenchymal cells, which results in the development of increased migratory and invasive cell behavior, serving as a vital mechanism of cancer progression. Hence, controlling the EMT for cancer treatment, including head and neck squamous cell carcinoma (HNSCC), is imperative. Among EMT-associated factors, transforming growth factor-β (TGF-β) is a well-established potent inducer. Recent research has revealed that CD147, a member of the immunoglobulin superfamily, promotes the EMT. However, the role of CD147 in the EMT and the following tumorigenicity in HNSCC has not been completely elucidated. This study aims to investigate the role of CD147 in the EMT and related tumorigenicity in HNSCC. The present study used two HNSCC cell lines, SAS and FaDu, for in vitro studies. In HNSCC cells, TGF-β1 induced spindle-shaped morphological changes, and western blot analysis revealed that TGF-β1 induced changes in EMT markers, downregulation of vimentin, and upregulation of E-cadherin, yet increased CD147. In addition, TGF-β1 increased cell migration in HNSCC cells. However, a TGF-β1-induced alteration in EMT makers was attenuated with CD147 silencing by small interfering RNA (siRNA) in SAS cells. In addition, the TGF-β1-induced cell invasion of SAS was attenuated with CD147 silencing. In conclusion, the present study suggests that CD147 mediates TGF-β1-induced EMT and tumorigenicity in HNSCC. Hence, CD147 may serve as a vital therapeutic target in HNSCC.

TGFβ promotes breast cancer stem cell self-renewal through an ILEI/LIFR signaling axis

FAM3C/Interleukin-like EMT Inducer (ILEI) is an oncogenic member of the FAM3 cytokine family and serves essential roles in both epithelial-mesenchymal transition (EMT) and breast cancer metastasis. ILEI expression levels are regulated through a non-canonical TGFβ signaling pathway by 3’-UTR-mediated translational silencing at the mRNA level by hnRNP E1. TGFβ stimulation or silencing of hnRNP E1 increases ILEI translation and induces an EMT program that correlates to enhanced invasion and migration. Recently, EMT has been linked to the formation of breast cancer stem cells (BCSCs) that confer both tumor cell heterogeneity as well as chemoresistant properties. Herein, we demonstrate that hnRNP E1 knockdown significantly shifts normal mammary epithelial cells to mesenchymal BCSCs in vitro and in vivo. We further validate that modulating ILEI protein levels results in the abrogation of these phenotypes, promoting further investigation into the unknown mechanism of ILEI signaling that drives tumor progression. We identify LIFR as the receptor for ILEI, which mediates signaling through STAT3 to drive both EMT and BCSC formation. Reduction of either ILEI or LIFR protein levels results in reduced tumor growth, fewer tumor initiating cells and reduced metastasis within the hnRNP E1 knock-down cell populations in vivo. These results reveal a novel ligand-receptor complex that drives the formation of BCSCs and represents a unique target for the development of metastatic breast cancer therapies.

Expression of Epithelial-Mesenchymal Transition Markers in Treated Pancreatic Ductal Adenocarcinoma

OBJECTIVES

Epithelial-mesenchymal transition (EMT) plays an important role in the progression, metastasis, and chemoresistance of pancreatic duct adenocarcinoma (PDAC); however, the expression of EMT markers and their clinical significance in PDAC patients who received neoadjuvant therapy (NAT) are unclear.

METHODS

We examined the expression of EMT markers, including Zeb-1 (zinc finger E-box-binding homeobox 1), E-cadherin, and vimentin by immunohistochemistry in 120 PDAC patients who received NAT and pancreatectomy from 1999 to 2007. The results were correlated with clinicopathologic parameters and survival.

RESULTS

Among 120 cases, 45 (37.5%) and 14 (11.7%) were positive for Zeb-1 and vimentin, respectively, and 25 (20.8%) were E-cadherin-low. The median overall survival and disease-free survival were 35.3 (standard deviation [SD], 2.8) and 15.9 (SD, 3.6) months, respectively, in vimentin-negative group compared with 16.1 (SD, 1.1) (P = 0.03) and 7.0 (SD, 1.1) months (P = 0.02) in the vimentin-positive group. In multivariate analysis, vimentin expression was an independent predictor of shorter disease-free survival (hazard ratio, 2.50; 95% confidence interval, 1.31-4.78; P = 0.016) and overall survival (hazard ratio, 2.55; 95% confidence interval, 1.33-4.89; P = 0.01).

CONCLUSIONS

Epithelial-mesenchymal transition markers are frequently expressed in treated PDAC. Vimentin expression is a prognostic biomarker for survival in PDAC patients who received NAT.

Enhancing Chemosensitivity of Breast Cancer Stem Cells by Downregulating SOX2 and ABCG2 Using Wedelolactone-encapsulated Nanoparticles

A major caveat in the treatment of breast cancer is disease recurrence after therapeutic regime at both local and distal sites. Tumor relapse is attributed to the persistence of chemoresistant cancer stem cells (CSC), which need to be obliterated along with conventional chemotherapy. Wedelolactone, a naturally occurring coumestan, demonstrates anticancer effects in different cancer cells, although with several limitations, and is mostly ineffective against CSCs. To enhance its biological activity in cancer cells and additionally target the CSCs, wedelolactone-encapsulated PLGA nanoparticles (nWdl) were formulated. Initial results indicated that nanoformulation of wedelolactone not only increased its uptake in breast cancer cells and the CSC population, it enhanced drug retention and sustained release within the cells. Enhanced drug retention was achieved by downregulation of SOX2 and ABCG2, both of which contribute to drug resistance of the CSCs. In addition, nWdl prevented epithelial-to-mesenchymal transition, suppressed cell migration and invasion, and reduced the percentage of breast cancer stem cells (BCSC) in MDA-MB-231 cells. When administered in combination with paclitaxel, which is known to be ineffective against BCSCs, nWdl sensitized the cells to the effects of paclitaxel and reduced the percentage of ALDH⁺ BCSCs and mammospheres. Furthermore, nWdl suppressed growth of solid tumors in mice and also reduced CD44⁺/CD24^-/low population. Taken together, our data imply that nWdl decreased metastatic potential of BCSCs, enhanced chemosensitivity through coordinated regulation of pluripotent and efflux genes, and thereby provides an insight into effective drug delivery specifically for obliterating BCSCs.

Mesenchymal stem cell-derived extracellular vesicles may promote breast cancer cell dormancy

Disseminated breast cancer cells have the capacity to metastasise to the bone marrow and reside in a dormant state within the mesenchymal stem cell niche. Research has focussed on paracrine signalling factors, such as soluble proteins, within the microenvironment. However, it is now clear extracellular vesicles secreted by resident mesenchymal stem cells into this microenvironment also play a key role in the initiation of dormancy. Dormancy encourages reduced cell proliferation and migration, while upregulating cell adhesion, thus retaining the cancer cells within the bone marrow microenvironment. Here, MCF7 breast cancer cells were treated with mesenchymal stem cell-derived extracellular vesicles, resulting in reduced migration in two-dimensional and three-dimensional culture, with reduced cell proliferation and enhanced adhesion, collectively supporting cancer cell dormancy.

Phenotypic and molecular dissection of metaplastic breast cancer and the prognostic implications

Metaplastic breast carcinoma (MBC) is relatively rare but accounts for a significant proportion of global breast cancer mortality. This group is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including spindle, squamous, chondroid, osseous, and rhabdomyoid features. Clinically, patients are more likely to present with large primary tumours (higher stage), distant metastases, and overall, have shorter 5-year survival compared to invasive carcinomas of no special type. The current World Health Organisation (WHO) diagnostic classification for this cancer type is based purely on morphology - the biological basis and clinical relevance of its seven sub-categories are currently unclear. By establishing the Asia-Pacific MBC (AP-MBC) Consortium, we amassed a large series of MBCs (n = 347) and analysed the mutation profile of a subset, expression of 14 breast cancer biomarkers, and clinicopathological correlates, contextualising our findings within the WHO guidelines. The most significant indicators of poor prognosis were large tumour size (T3; p = 0.004), loss of cytokeratin expression (lack of staining with pan-cytokeratin AE1/3 antibody; p = 0.007), EGFR overexpression (p = 0.01), and for 'mixed' MBC, the presence of more than three distinct morphological entities (p = 0.007). Conversely, fewer morphological components and EGFR negativity were favourable indicators. Exome sequencing of 30 cases confirmed enrichment of TP53 and PTEN mutations, and intriguingly, concurrent mutations of TP53, PTEN, and PIK3CA. Mutations in neurofibromatosis-1 (NF1) were also overrepresented [16.7% MBCs compared to ∼5% of breast cancers overall; enrichment p = 0.028; mutation significance p = 0.006 (OncodriveFM)], consistent with published case reports implicating germline NF1 mutations in MBC risk. Taken together, we propose a practically minor but clinically significant modification to the guidelines: all WHO_1 mixed-type tumours should have the number of morphologies present recorded, as a mechanism for refining prognosis, and that EGFR and pan-cytokeratin expression are important prognostic markers. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Solute Carrier Family 27 Member 4 (SLC27A4) Enhances Cell Growth, Migration, and Invasion in Breast Cancer Cells

Fatty acid metabolism is important in the regulation of breast cancer progression. Some of the proteins involved in fatty acid transport have been demonstrated to promote the proliferation, migration, and invasion in breast cancer cells. Solute carrier family 27 member 4 (SLC27A4) is a fatty acid transporter protein and is related to very long chain acyl-CoA synthetase activity. In the present study, bioinformatic analysis revealed that relatively high SLC27A4 expression was observed in all subtypes of breast tumor tissues when compared to normal breast tissues. Silencing SLC27A4 expression significantly reduced uptake of free fatty acids in two breast cancer cell lines, Hs578T and MDA-MB-231. Cell growth inhibition was observed in SLC27A4-silenced Hs578T and cell cycle was arrested at G2/M. In addition, the capacity of migration and invasion decreased in both cell lines after knockdown of SLC27A4. The epithelial–mesenchymal transition signaling pathway was inhibited because protein expression of Slug, vimentin, α-smooth muscle actin, and other regulators was lower than that in control cells. Taken together, our results confirm that high SLC27A4 is associated with tumor progression in breast cancer cells. It is worth investigating whether SLC27A4 serves a diagnostic marker and therapeutic target in further studies.

Epithelial membrane protein 2: a novel biomarker for circulating tumor cell recovery in breast cancer

PURPOSE

EpCAM is a common marker used in the detection of circulating tumor cells (CTC). Disseminated cancer cells display the characteristics of epithelial-to-mesenchymal transition events. The purpose of this study was to assess the potential of epithelial membrane protein 2 (EMP2) as a novel biomarker for CTC retrieval in breast cancer.

METHODS

MCF7 and MDA-MB-231 cells were stained with either anti-EpCAM or anti-EMP2 mAbs, respectively, followed by flow cytometric assay to measure their expression levels. PBMCs isolated from healthy donors were used for breast cancer cell spiking. CD45-depleted PBMCs from breast cancer patients' blood were used for CTC capturing. Immunomagnetic separation was used to enrich breast cancer cells. Cytospin centrifugation was performed to concentrate the captured cells, followed by immunofluorescence staining with anti-CD45 mAb, anti-pan cytokeratin mAb and DAPI. Fluorescent images were taken using a confocal microscope for CTC counts.

RESULT

MDA-MB-231 cells had 2.56 times higher EMP2 expression than MCF7 cells, and EMP2 had a significantly higher capture efficiency than EpCAM for MCF7 cells. Furthermore, anti-EMP2 was capable of capturing MCF7 cells that escaped in the flow-through of anti-EpCAM. Likewise, EMP2 had a significantly higher capture efficiency on MDA-MB-231 cells when compared to MCF7 cells. Most importantly, EMP2 biomarker was successfully used for CTC capture in patients with primary breast cancer.

CONCLUSIONS

EMP2 is superior to EpCAM for capturing both MCF7 and MDA-MB-231 cells. Additionally, EMP2 is a novel biomarker and capable of capturing breast cancer cells in patient blood samples.

High-throughput chemical screening to discover new modulators of microRNA expression in living cells by using graphene-based biosensor

MicroRNAs (miRNAs) are important regulatory RNAs that control gene expression in various biological processes. Therefore, control over the disease-related miRNA expression is important both for basic research and for a new class of therapeutic modality to treat serious diseases such as cancer. Here, we present a high-throughput screening strategy to identify small molecules that modulate miRNA expression in living cells. The screen enables simultaneous monitoring of the phenotypic cellular changes associated with the miRNA expression by measuring quantitative fluorescent signals corresponding to target miRNA level in living cells based on a novel biosensor composed of peptide nucleic acid and nano-sized graphene oxide. In this study, the biosensor based cellular screening of 967 compounds (including FDA-approved drugs, enzyme inhibitors, agonists, and antagonists) in cells identified four different classes of small molecules consisting of (i) 70 compounds that suppress both miRNA-21 (miR-21) expression and cell proliferation, (ii) 65 compounds that enhance miR-21 expression and reduce cell proliferation, (iii) 2 compounds that suppress miR-21 expression and increase cell proliferation, and (iv) 21 compounds that enhance both miR-21 expression and cell proliferation. We further investigated the hit compounds to correlate cell morphology changes and cell migration ability with decreased expression of miR-21.

CYP24A1 depletion facilitates the antitumor effect of vitamin D3 on thyroid cancer cells

It has been demonstrated that 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1) is a key enzyme that neutralizes vitamin D activity, which may have an anti-tumor effect. Therefore, the aim of the current study was to explore the effect of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25-D3) on thyroid cancer cells following the downregulation of CYP24A1. A Cell Counting Kit-8 assay identified that CYP24A1 knockdown enhanced the anti-proliferative effects of 1,25-D3 on thyroid cancer cells. Furthermore, the results of the scratch wound and Transwell assays indicated that CYP24A1 knockdown enhanced the inhibitory effect of 1,25-D3 on cell migration. The results from reverse transcription-quantitative polymerase chain reaction and western blot analysis indicated that treatment with 1,25-D3 and CYP24A1 knockdown synergistically enhanced the expression of the epithelial-related gene E-cadherin and decreased the expression of the mesenchymal-related genes N-cadherin and vimentin. Following CYP24A1 knockdown and treatment with 1,25-D3, the expression of matrix metalloproteinase 2 and metalloproteinase inhibitor 1 were significantly decreased and increased, respectively, compared with the group that underwent treatment with 25-D3 alone. Furthermore, protein kinase B (Akt) and β-catenin activity was significantly decreased by this synergetic effect compared with the group that underwent treatment with 1,25-D3 alone. The results of the current study suggest that CYP24A1 knockdown contributes to the anti-tumor effect of 1,25-D3 and that this effect may be due to deactivation of the Akt and β-catenin signaling pathways. Therefore, CYP24A1 knockdown and 1,25-D3 treatment may be used synergistically as a novel therapeutic strategy to treat patients with thyroid cancer.

Effects of long non-coding RNA HOST2 on cell migration and invasion by regulating MicroRNA let-7b in breast cancer

The study intends to investigate the effects of long non-coding RNA HOST2 (lncRNA HOST2) on cell migration and invasion by regulating microRNA let-7b (let-7b) in breast cancer. Breast cancer and adjacent normal tissues were collected from 98 patients with breast cancer. Breast cancer MCF-7 cells were divided into the blank, negative control (NC), pcDNA3-Mock, siHOST2, let-7b inhibitor, pcDNA3-HOST2, let-7b mimic, pcDNA3-HOST2 + let-7b mimic, and siHOST2 + let-7b inhibitor groups. RT-qPCR was used to detect the mRNA expressions of HOST2, let-7b, and c-Myc. Western blotting was conducted to measure the c-Myc expression. Scratch test and Transwell assay were applied to detect the cell motility, migration, and invasion. Xenograft tumor in nude mice was performed to evaluate the effect of different transfection on the tumor growth. Compared with adjacent normal tissues, HOST2 expression was higher but let-7b expression lower in breast cancer tissues. HOST2 expression in breast cancer cells was remarkably increased compared with that in the normal breast epithelial MCF-10A cells. In MCF-7 cells, in comparison with the blank and NC groups, expressions of HOST2 and c-Myc were reduced, but let-7b expression was remarkably elevated in the siHOST2 and let-7b mimic groups; the let-7b inhibitor group exhibited higher expressions of HOST2 and c-Myc but lower let-7b expression. Overexpression of HOST2 could promote cell motility, migration and invasion, thus enhancing the growth of breast cancer tumor. By inhibiting HOST2, opposite trends were found. LncRNA HOST2 promotes cell migration and invasion by inhibiting let-7b in breast cancer patients.

miR-302a-5p/367-3p-HMGA2 axis regulates malignant processes during endometrial cancer development

BACKGROUND

Metastasis is one of the main reasons for treatment failure in endometrial cancer. Notably, high mobility group AT-hook 2 (HMGA2) has been recognized as a driving factor of tumour metastasis. microRNAs (miRNAs) are powerful posttranscriptional regulators of HMGA2.

METHODS

The binding sites of miR-302a-5p and miR-367-3p on HMGA2 mRNA were identified using bioinformatics prediction software and were validated via luciferase assay. The expression levels of miR-302a-5p and miR-367-3p were detected using quantitative real-time PCR and in situ hybridization. Western blotting and immunohistochemistry were used to detect the levels of HMGA2 and epithelial-mesenchymal transition pathway-related proteins. Co-immunoprecipitation was used to detect protein interactions. The roles of miR-302a-5p and miR-367-3p in the regulation of HMGA2 during the progression of endometrial cancer were investigated using both in vitro and in vivo assays.

RESULTS

In the present study, high HMGA2 expression was correlated with poor clinical outcomes in endometrial cancer. The binding sites of miRNAs on HMGA2 mRNA were identified using bioinformatics prediction software and were validated via luciferase assay. In the endometrial cancer cell lines Ishikawa and HEC-1A, the overexpression of miR-302a-5p/367-3p significantly inhibited the expression of HMGA2 mRNA. In endometrial cancer tissues, we showed that miR-302a-5p and miR-367-3p were significantly downregulated and thus inversely correlated with HMGA2. The miR-302a-5p and miR-367-3p expression levels were closely correlated with FIGO stage and lymph node metastasis. High expression of miR-302a-5p/367-3p was correlated with high survival rates in endometrial cancer. In addition, miR-302a-5p/367-3p suppressed the malignant behaviour of endometrial carcinoma cells via the inhibition of HMGA2 expression.

CONCLUSION

Our findings indicate that miR-302a-5p/367-3p-mediated expression of HMGA2 regulates the malignant behaviour of endometrial carcinoma cells, which suggests that the miR-302a-5p/367-3p-HMGA2 axis may be a predictive biomarker of endometrial cancer metastasis and patient survival and a potential therapeutic target in metastatic endometrial cancer.

Claudin-3 Inhibits Lung Squamous Cell Carcinoma Cell Epithelial-mesenchymal Transition and Invasion via Suppression of the Wnt/β-catenin Signaling Pathway

Altered expression of claudin-3 (CLDN3), a key cytoskeletal structural protein of the tight junctions in the epithelium, is associated with the development and metastasis of various human cancers. CLDN3 expression has been shown to be significantly associated with the prognosis of lung squamous cell carcinoma (SqCC). This study investigated the role of CLDN3 in inhibiting lung SqCC cell migration and invasion as well as the underlying molecular mechanisms. The CLDN3 levels were assessed between 20 paired lung SqCC tissues and adjacent normal tissues using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The ectopic CLDN3 overexpression or knockdown was generated by using a plasmid carrying CLDN3 cDNA or shRNA, respectively. CLDN3 expression was significantly reduced in lung SqCC tissues vs. the adjacent normal tissues. The ectopic CLDN3 overexpression markedly inhibited the migration, invasion, and epithelial-mesenchymal transition (EMT) of lung cancer H520 cells, whereas CLDN3 knockdown had an inverse effect on SK-MES-1 cells. However, cell viability and plate colony formation assays showed that both CLDN3 knockdown and overexpression did not affect SqCC cell proliferation. Both tissue and cell data revealed that CLDN3 expression was significantly associated with the expression of the EMT biomarkers E-cadherin and Vimentin. Furthermore, CLDN3-modulated EMT and expression of the EMT markers were through regulation of the Wnt/β-catenin signaling pathway. In conclusion, this study identified reduced CLDN3 expression in lung SqCC tissues, which was associated with the progression and metastasis of lung SqCC and was attributed to EMT by activation of the Wnt pathway. Thus, CLDN3 could be further evaluated as a novel biomarker for predicting the prognosis of lung SqCC and as a target for the treatment of lung SqCC in the future.