Initiation Of Epithelial To Mesenchymal Transition Research Articles

LncRNA MALAT1 Regulates Hyperglycemia Induced EMT in Keratinocyte via miR-205.

Epithelial-to-mesenchymal transition (EMT) is critical to cutaneous wound healing. When skin is injured, EMT activates and mobilizes keratinocytes toward the wound bed, therefore enabling re-epithelialization. This process becomes dysregulated in patients with diabetes mellitus (DM). Long non-coding RNAs (lncRNAs) regulate many biological processes. LncRNA-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) influences numerous cellular processes, including EMT. The objective of the current study is to explore the role of MALAT1 in hyperglycemia (HG)-induced EMT. The expression of MALAT1 was found to be significantly upregulated, while the expression of miR-205 was downregulated in diabetic wounds and high-glucose-treated HaCaT cells. The initiation of EMT in HaCaT cells from hyperglycemia was confirmed by a morphological change, the increased expression of CDH2, KRT10, and ACTA2, and the downregulation of CDH1. The knockdown of MALAT1 was achieved by transfecting a small interfering RNA (SiRNA). MALAT1 and miR-205 were found to modulate HG-induced EMT. MALAT1 silencing or miR-205 overexpression appears to attenuate hyperglycemia-induced EMT. Mechanistically, MALAT1 affects HG-induced EMT through binding to miR-205 and therefore inducing ZEB1, a critical transcription factor for EMT. In summary, lncRNA MALAT1 is involved in the hyperglycemia-induced EMT of human HaCaT cells. This provides a new perspective on the pathogenesis of diabetic wounds.

Targeting Epithelial to Mesenchymal Transition in Breast Cancer with Bioactive Compounds derived from Solanum surattense: A GC-MS and Molecular Docking approach

The epithelial to mesenchymal transition (EMT) has been associated with the invasion and migration of tumor cells, thus playing a fundamental role in cancer progression and metastasis. Breast cancer is a heterogeneous disease, which has been regarded as one of the leading causes of death amongst women globally. The initiation of EMT in breast cancer embraces the involvement of multiple signaling pathways. The involvement of a few factors present in EMT has left a prominent impact on shaping breast cancer development. Solanum surattense, belonging to the family Solanaceae, possesses numerous therapeutic properties due to the presence of several substances. In this study, we focused on major key players genes in promoting EMT, which increases the severity of cancer. Using GC/MS analysis, the active compounds from Solanum surattense were predicted. Molecular docking studies for this extracted active compounds were performed against the genes responsible for EMT using the PatchDock server. The docked complexes were then visualized using PyMOL. Results obtained from the molecular docking showed the inhibitory effect against the EMT pathway, thus inhibiting breast cancer progression.

Circ-OMAC drives metastasis in oral squamous cell carcinoma.

Accumulating studies have proved that the circular RNAs (circRNAs) play vital roles in human cancers. However, few circRNAs have been elucidated with lymph node metastasis. This study demonstrated that circ-oral cancer metastasis-associated circRNA (circ-OMAC) is required to regulate the oral squamous cell carcinoma (OSCC) metastasis. The circ-OMAC were detected by circRNA-sequencing and further verified by in situ hybridization (ISH). The role of circ-OMAC was assessed by transwell assay and wound healing assay. Mechanistically, circ-OMAC regulated OSCC metastasis by initiating the epithelial-to-mesenchymal transition (EMT) signaling pathway. Our findings suggested that circ-OMAC was aberrantly elevated in the metastatic lymph nodes as compared to primary OSCC tissues. OSCC patients with high levels of circ-OMAC were prone to a poor prognosis. By developing functional assays, we confirmed that circ-OMAC promotes metastasis of OSCC cells via initiation of EMT pathways. We provide new insights whereby Circ-OMAC as an oncogene is a potential therapeutic target and prognostic marker in oral cancer.

Matrix Metalloproteinases in Chemoresistance: Regulatory Roles, Molecular Interactions, and Potential Inhibitors.

Cancer is one of the major causes of death worldwide. Its treatments usually fail when the tumor has become malignant and metastasized. Metastasis is a key source of cancer recurrence, which often leads to resistance towards chemotherapeutic agents. Hence, most cancer-related deaths are linked to the occurrence of chemoresistance. Although chemoresistance can emerge through a multitude of mechanisms, chemoresistance and metastasis share a similar pathway, which is an epithelial-to-mesenchymal transition (EMT). Matrix metalloproteinases (MMPs), a class of zinc and calcium-chelated enzymes, are found to be key players in driving cancer migration and metastasis through EMT induction. The aim of this review is to discuss the regulatory roles and associated molecular mechanisms of specific MMPs in regulating chemoresistance, particularly EMT initiation and resistance to apoptosis. A brief presentation on their potential diagnostic and prognostic values was also deciphered. It also aimed to describe existing MMP inhibitors and the potential of utilizing other strategies to inhibit MMPs to reduce chemoresistance, such as upstream inhibition of MMP expressions and MMP-responsive nanomaterials to deliver drugs as well as epigenetic regulations. Hence, manipulation of MMP expression can be a powerful tool to aid in treating patients with chemo-resistant cancers. However, much still needs to be done to bring the solution from bench to bedside.

FBI-1 inhibits epithelial-to-mesenchymal transition, migration, and invasion in lung adenocarcinoma A549 cells by downregulating transforming growth factor-β1 signaling pathway.

The factor binding inducer of short transcripts-1 (FBI-1) is a POZ-domain Kruppel-like (POK) family of transcription factors and is known as a proto-oncogene or tumor suppressor in various carcinomas. However, the role of FBI-1 on epithelial-to-mesenchymal transition(EMT) and invasiveness in lung cancer remains unknown. Preliminarily, clinical data such as tissue microarray, Kaplan-Meier, and Oncomine were analyzed to confirm the correlation between lung cancer metastasis and FBI-1. To investigate the function of FBI-1 in EMTin lung cancer, EMT was measured in FBI-1-deficient or FBI-1-overexpressing cells. FBI-1 showed decreased expression in tumors metastasized to lymph nodes than in the primary tumor. In addition, it was also associated with improved survival rates of lung cancer patients. FBI-1 knockdown improved E-to-N-cadherin switching, migration, and invasion in A549 cells, similar to the initiation of EMT stimulated by transforming growth factor- β1 (TGF-β1). In contrast, overexpression of FBI-1 inhibited the transcription and activation of Smad2, thereby interfering with EMT, despite stimulation by TGF-β1. These results suggest that FBI-1 plays a negative role in EMT in lung cancer via the TGF-β1 signaling pathway, implying its use as a new potential therapeutic target and diagnostic indicator for early stage of lung cancer metastasis.

Implications of ABCC4-Mediated cAMP Eflux for CRC Migration.

Simple SummaryCancer cells have developed a number of mechanisms to overcome anticancer therapy; the active efflux of drugs from cells via multidrug resistance proteins (MRPs) is one of them. MRPs belong to the superfamily of ATP binding cassette (ABC) proteins. It was hypothesized that the inhibition of ABC drug transporter activity during cancer therapy could sensitize drug-resistant tumors and/or improve the initial activity of anticancer agents. We demonstrated that the pharmacological inhibition of ABCC4 increases the migratory rate and invasive protrusion formation in colorectal cancer (CRC). Thus, during the use of ABCC4 inhibitors to reduce chemotherapy resistance or drugs that are potential substrates of ABCC4, the indirect effect on cancer metastasis should be taken into consideration and may be important in selecting a therapy scheme for patients.Colorectal cancer (CRC) presents significant molecular heterogeneity. The cellular plasticity of epithelial to mesenchymal transition (EMT) is one of the key factors responsible for the heterogeneous nature of metastatic CRC. EMT is an important regulator of ATP binding cassette (ABC) protein expression; these proteins are the active transporters of a broad range of endogenous compounds and anticancer drugs. In our previous studies, we performed a transcriptomic and functional analysis of CRC in the early stages of metastasis induced by the overexpression of Snail, the transcription factor involved in EMT initiation. Interestingly, we found a correlation between the Snail expression and ABCC4 (MRP4) protein upregulation. The relationship between epithelial transition and ABCC4 expression and function in CRC has not been previously defined. In the current study, we propose that the ABCC4 expression changes during EMT and may be differentially regulated in various subpopulations of CRC. We confirmed that ABCC4 upregulation is correlated with the phenotype conversion process in CRC. The analysis of Gene Expression Omnibus (GEO) sets showed that the ABCC4 expression was elevated in CRC patients. The results of a functional study demonstrated that, in CRC, ABCC4 can regulate cell migration in a cyclic nucleotide-dependent manner.

Total Blood Exosomes in Breast Cancer: Potential Role in Crucial Steps of Tumorigenesis.

Exosomes are crucial players in cell-to-cell communication and are involved in tumorigenesis. There are two fractions of blood circulating exosomes: free and cell-surface-associated. Here, we compared the effect of total blood exosomes (contain plasma exosomes and blood cell-surface-associated exosomes) and plasma exosomes from breast cancer patients (BCPs, n = 43) and healthy females (HFs, n = 35) on crucial steps of tumor progression. Exosomes were isolated by ultrafiltration, followed by ultracentrifugation, and characterized by cryo-electron microscopy (cryo-EM), nanoparticle tracking analysis, and flow cytometry. Cryo-EM revealed a wider spectrum of exosome morphology with lipid bilayers and vesicular internal structures in the HF total blood in comparison with plasma. No differences in the morphology of both exosomes fractions were detected in BCP blood. The plasma exosomes and total blood exosomes of BCPs had different expression levels of tumor-associated miR-92a and miR-25-3p, induced angiogenesis and epithelial-to-mesenchymal transition (EMT), and increased the number of migrating pseudo-normal breast cells and the total migration path length of cancer cells. The multidirectional effects of HF total blood exosomes on tumor dissemination were revealed; they suppress the angiogenesis and total migration path length of MCF10A, but stimulate EMT and increase the number of migrating MCF10A and the total path length of SKBR3 cells. In addition, HF plasma exosomes enhance the metastasis-promoting properties of SKBR3 cells and stimulate angiogenesis. Both cell-free and blood cell-surface-associated exosomes are involved in the crucial stages of carcinogenesis: the initiation of EMT and the stimulation of proliferation, cell migration, and angiogenesis. Thus, for the estimation of the diagnostic/prognostic significance of circulating exosomes in the blood of cancer patients more correctly, the total blood exosomes, which consist of plasma exosomes and blood cell-surface-associated exosomes should be used.

Targeted DNA oxidation by LSD1-SMAD2/3 primes TGF-β1/ EMT genes for activation or repression.

The epithelial-to-mesenchymal transition (EMT) is a complex transcriptional program induced by transforming growth factor β1 (TGF-β1). Histone lysine-specific demethylase 1 (LSD1) has been recognized as a key mediator of EMT in cancer cells, but the precise mechanism that underlies the activation and repression of EMT genes still remains elusive. Here, we characterized the early events induced by TGF-β1 during EMT initiation and establishment. TGF-β1 triggered, 30–90 min post-treatment, a nuclear oxidative wave throughout the genome, documented by confocal microscopy and mass spectrometry, mediated by LSD1. LSD1 was recruited with phosphorylated SMAD2/3 to the promoters of prototypic genes activated and repressed by TGF-β1. After 90 min, phospho-SMAD2/3 downregulation reduced the complex and LSD1 was then recruited with the newly synthesized SNAI1 and repressors, NCoR1 and HDAC3, to the promoters of TGF-β1-repressed genes such as the Wnt soluble inhibitor factor 1 gene (WIF1), a change that induced a late oxidative burst. However, TGF-β1 early (90 min) repression of transcription also required synchronous signaling by reactive oxygen species and the stress-activated kinase c-Jun N-terminal kinase. These data elucidate the early events elicited by TGF-β1 and the priming role of DNA oxidation that marks TGF-β1-induced and -repressed genes involved in the EMT.

Aspirin inhibits TGFβ2-induced epithelial to mesenchymal transition of lens epithelial cells: selective acetylation of K56 and K122 in histone H3.

Posterior capsule opacification (PCO) is a complication after cataract surgery that can disrupt vision. The epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) in response to transforming growth factor β2 (TGFβ2) has been considered an obligatory mechanism for PCO. In this study, we tested the efficacy of aspirin in inhibiting the TGFβ2-mediated EMT of human LECs, LECs in human lens capsular bags, and lensectomized mice. In human LECs, the levels of the EMT markers α-smooth muscle actin (α-SMA) and fibronectin were drastically reduced by treatment with 2 mM aspirin. Aspirin also halted the EMT response of TGFβ2 when introduced after EMT initiation. In human capsular bags, treatment with 2 mM aspirin significantly suppressed posterior capsule wrinkling and the expression α-SMA in capsule-adherent LECs. The inhibition of TGFβ2-mediated EMT in human LECs was not dependent on Smad phosphorylation or MAPK and AKT-mediated signaling. We found that aspirin significantly increased the acetylation of K56 and K122 in histone H3 of human LECs. Chromatin immunoprecipitation assays using acetyl-H3K56 or acetyl-H3K122 antibody revealed that aspirin blocked the TGFβ2-induced acetylation of H3K56 and H3K122 at the promoter regions of ACTA2 and COL1A1. After lensectomy in mice, we observed an increase in the proliferation and α-SMA expression of the capsule-adherent LECs, which was ameliorated by aspirin administration through drinking water. Taken together, our results showed that aspirin inhibits TGFβ2-mediated EMT of LECs, possibly from epigenetic down-regulation of EMT-related genes.

LncRNA SNHG7 contributes to tumorigenesis and progression in breast cancer by interacting with miR-34a through EMT initiation and the Notch-1 pathway

The long non-coding RNA (lncRNA) small nucleolar RNA host gene 7 (SNHG7) has been reported to be upregulated and contribute to carcinogenesis, progression and poor prognosis of many cancers. However, expression and function of SNHG7 in breast cancer remain unclear. Herein, we found that SNHG7 was significantly up-regulated in breast cancer tissues and cell lines. SNHG7 knockdown significantly inhibited MCF-7 cell proliferation and invasion, while SNHG7 overexpression dramatically promoted T47D cell proliferation and invasion. Xenograft experiments in vivo showed that SNHG7 knockdown significantly inhibited tumor growth in mice. In terms of mechanism, miR-34a was confirmed to be the target of SNHG7, and SNHG7 could sponge miR-34a to inhibit the expression of miR-34a. In vivo and in vitro experiments both showed that SNHG7 targeted miR-34a and promoted epithelial-to-mesenchymal transition (EMT) initiation and the Notch-1 pathway in breast cancer. In conclusion, SNHG7 promoted breast cancer tumorigenesis and progression by sponging miR-34a through EMT initiation and the Notch-1 pathway. These findings contribute to a better understanding of breast cancer pathogenesis and further provide the theoretical fundamental basis for treatment.

Draxin acts as a molecular rheostat of canonical Wnt signaling to control cranial neural crest EMT.

Neural crest cells undergo a spatiotemporally regulated epithelial-to-mesenchymal transition (EMT) that proceeds head to tailward to exit from the neural tube. In this study, we show that the secreted molecule Draxin is expressed in a transient rostrocaudal wave that mirrors this emigration pattern, initiating after neural crest specification and being down-regulated just before delamination. Functional experiments reveal that Draxin regulates the timing of cranial neural crest EMT by transiently inhibiting canonical Wnt signaling. Ectopic maintenance of Draxin in the cranial neural tube blocks full EMT; while cells delaminate, they fail to become mesenchymal and migratory. Loss of Draxin results in premature delamination but also in failure to mesenchymalize. These results suggest that a pulse of intermediate Wnt signaling triggers EMT and is necessary for its completion. Taken together, these data show that transient secreted Draxin mediates proper levels of canonical Wnt signaling required to regulate the precise timing of initiation and completion of cranial neural crest EMT.

Activated CXCL5-CXCR2 axis promotes the migration, invasion and EMT of papillary thyroid carcinoma cells via modulation of β-catenin pathway

Initiation of epithelial-to-mesenchymal transition (EMT) is common in papillary thyroid carcinoma (PTC) and may contribute to its metastasis. Aims of the present study are to investigate whether and how the C-X-C motif chemokine ligand (CXCL)-5/C-X-C motif receptor 2 (CXCR2) axis affects PTC metastasis, with a focus on the EMT process. Herein, two PTC cell lines, KTC-1 and B-CPAP cells, identified as CXCR2-positive cells were used as the cell model. We found that a 24-h stimulation of 1 or 10 nM recombinant human CXCL5 (rhCXCL5) enhanced the migration and invasion of both KTC-1 and B-CPAP cells without affecting their proliferation. The migration- and invasion-promoting effects of rhCXCL5 were attenuated if CXCR2 was silenced by its specific short hairpin RNAs (shRNAs). EMT initiation is defined as downregulation of epithelial-cadherin (E-cadherin) and upregulation of N-cadherin, Vimentin and Snail. Our data showed that rhCXCL5-induced EMT in PTC cells was suppressed by CXCR2 shRNA. Furthermore, the active CXCL5-CXCR2 axis enhanced the phosphorylation of Akt at Ser 473 residue and that of glycogen synthase kinase-3 (GSK-3β) at Ser 9 residue, and accelerated the nuclear accumulation of β-catenin in PTC cells. Re-expression of the active form of β-catenin in PTC cells rescued their impaired invasiveness caused by the blockade of CXCL5-CXCR2 axis. In addition, CXCL5 and CXCR2 were overexpressed in the metastatic lymph nodes obtained from 18 patients with PTC. In summary, our study demonstrates that the activated CXCL5-CXCR2 axis contributes to the metastatic phenotype of PTC cells by modulating Akt/GSK-3β/β-catenin pathway.

ERK1/2 signaling is required for the initiation but not progression of TGFβ-induced lens epithelial to mesenchymal transition (EMT)

Transforming Growth Factor Beta (TGFβ) potently induces lens epithelial to mesenchymal transition (EMT). The resultant mesenchymal cells resemble those found in plaques of human forms of subcapsular cataract. Smad signaling has long been implicated as the sole driving force of TGFβ-mediated activity. Rat lens epithelial explants were used to examine the role of the Smad-independent signaling, namely the MAPK/ERK1/2 signaling pathway, in the initiation and progression of TGFβ-induced EMT. Phase contrast microscopy was used to observe the morphological changes associated with TGFβ-induced EMT in this model, including cell elongation, cell membrane blebbing, cell loss as indicated by the area of bare capsule and capsular wrinkling. The levels of Smad2, Smad2/3 and ERK1/2 phosphorylation measured using western blotting confirmed that the addition of UO126 was sufficient in blocking all TGFβ-induced ERK1/2 activation, as well as reducing Smad signaling at 18 h. Immunofluorescent labeling and further western blotting confirmed that TGFβ-induced EMT was associated with an increase in α-smooth muscle actin (α-SMA) and a reduction of E-cadherin at cell borders. Pre-treatment with UO126 was effective at blocking the TGFβ-induced EMT, as evidenced by a reduction of α-SMA expression and protein labeling, E-cadherin labeling at cell borders, and a reduction of cell loss, cell elongation and capsular wrinkling. Post-treatment with UO126 at 2 and 6 h after TGFβ addition was also effective at blocking EMT while post-treatment with UO126 at 24 and 48 h was not sufficient in hampering TGFβ-induced EMT. Our data implicates ERK1/2 signaling in the initiation but not the progression of TGFβ-induced EMT in rat lens epithelial cells. The tight regulation of intracellular signaling pathways such as ERK1/2 are required for the maintenance of lens epithelial cell integrity and hence tissue transparency. A greater understanding of the molecular mechanisms that drive the induction and progression of EMT in the lens will provide the basis for potential therapeutics for human cataract.

Epigenetics of epithelial-to-mesenchymal transition in pancreatic carcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant diseases with late diagnosis, rapid progression, high invasiveness, and early metastasis. Epithelial-to-mesenchymal transition (EMT) is a crucial step in metastasis that enables polarized immotile epithelial cells to gain fibroblast-like mesenchymal abilities such as enhanced motility. The dynamic process of EMT in PDAC with its powerful influence on disease progression and especially metastasis is of vigorous interest in biomedical research to elucidate its signaling pathways and regulation mechanisms. It is evident that epigenetics such as histone and DNA modification or noncoding RNAs such as microRNAs and long noncoding RNAs are of high importance in initiation and progress of EMT in PDAC. This review analyzes the latest research dealing with EMT and its epigenetic regulation in PDAC and summarizes its potentials in diagnostic, prognostic, and therapeutic management.

EZH2 inhibition promotes epithelial-to-mesenchymal transition in ovarian cancer cells.

Cancer cells acquire essential characteristics for metastatic dissemination through the process of epithelial-to-mesenchymal transition (EMT), which is regulated by gene expression and chromatin remodeling changes. The enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the polycomb repressive complex 2 (PRC2), catalyzes trimethylation of lysine 27 of histone H3 (H3K27me3) to repress gene transcription. Here we report the functional roles of EZH2-catalyzed H3K27me3 during EMT in ovarian cancer (OC) cells. TGF-β-induced EMT in SKOV3 OC cells was associated with decreased levels of EZH2 and H3K27me3 (P<0.05). These effects were delayed (~72 h relative to EMT initiation) and coincided with increased (>15-fold) expression of EMT-associated transcription factors ZEB2 and SNAI2. EZH2 knockdown (using siRNA) or enzymatic inhibition (by GSK126) induced EMT-like changes in OC cells. The EMT regulator ZEB2 was upregulated in cells treated with either approach. Furthermore, TGF-β enhanced expression of ZEB2 in EZH2 siRNA- or GSK126-treated cells (P<0.01), suggesting that H3K27me3 plays a role in TGF-β-stimulated ZEB2 induction. Chromatin immunoprecipitation assays confirmed that TGF-β treatment decreased binding of EZH2 and H3K27me3 to the ZEB2 promoter (P<0.05). In all, these results demonstrate that EZH2, by repressing ZEB2, is required for the maintenance of an epithelial phenotype in OC cells.

Abstract 1582: Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering EMT induction

Abstract In the last decades it has been demonstrated that the stroma surrounding tumor not only provides mechanical support, but profoundly influences the outcome of the primary tumor and its possible relapse, impacting on proliferation, metastatic progression and resistance to therapies. Major components of the stroma in most types of human carcinomas are the Tumor-Associated Stromal Cells (TASC). Different sources have been proposed for this population, ranging from the resident fibroblasts to bone marrow-derived mesenchymal stromal cells (BM-MSC) recruited to the trans-differentiated epithelial and endothelial cells, but the scenario is still unclear. Moreover, TASC have an intrinsic heterogeneity, combined also with the presence of multiple subpopulations, and they share several markers with other cell subsets of the stroma, thus making the identification of this population, based on the expression of specific markers, an arduous task. In this intricate context, we aim to address phenotypic and functional characterization of TASC isolated from colorectal cancer specimens, and to analyze TASC-mediated effects on CRC development and progression in vivo. TASC were characterized for phenotype and differentiation capacity. Human CRC cells were cultured in the presence or absence of TASC for five days. After co-culture tumor cells were sorted by flow cytometry and evaluated for the expression of EMT-related genes by Real Time PCR and for in vitro invasiveness by chemoinvasion assay. Furthermore, their tumorigenicity and the metastatic potential were assessed upon subcutaneous and intracoecally injection in NOD/SCID mice. Developed tumors, metastatic foci and circulating tumor cells were assessed by histology, flow cytometry and Imaging Flow Cytometry. Our results indicate that TASC resemble BM-MSC in morphology and phenotype. They also comprise a multipotent subpopulation that is able to differentiate into adipogenic and osteogenic lineage. After co-culture with CRC cells, TASC express membrane-bound TGF-β, through which they are capable to trigger epithelial-to-mesenchymal transition (EMT). Upon subcutaneous injection in NOD/SCID mice, tumor cells co-cultured or admixed with TASC before injection, show a faster growth kinetic and develop larger tumor masses as compared to tumor cells alone. Furthermore developed tumor masses are characterized by a higher vessel density. Notably, upon intracoecal injection TASC presence or conditioning leads to a higher metastatic formation in lungs and livers and an increased number of circulating tumor cells in the peripheral blood, most importantly comprising cells undergoing EMT. Our data clearly show that the stromal component in the human colorectal cancer microenvironment increases the malignancy of tumor cells, by providing pro-mitogenic factors and by triggering EMT initiation in vitro and in vivo, thus promoting tumorigenicity and metastasis formation in vivo. Citation Format: Valentina Mele, Valeria Governa, Manuele G. Muraro, Jesus F. Glaus Garzon, Lubor Borsig, Silvio Daester, Raoul Droeser, Daniel Oertli, Markus Zuber, Raffaele Rosso, Giulio C. Spagnoli, Giandomenica Iezzi. Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering EMT induction. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1582.

Regulation of epithelial to mesenchymal transition in bovine conceptuses through the interaction between follistatin and activin A

Dynamic changes in bovine conceptus and endometrium occur during early gestation, in which the conceptus undergoes epithelial to mesenchymal transition (EMT) after the conceptus attachment to endometrium. To characterize EMT inducing factors, we initially undertook iTRAQ analysis with bovine uterine flushing (UF) obtained from pregnant animals on days 17 (P17: pre-attachment) and 20 (P20: post-attachment). The iTRAQ analysis demonstrated that follistatin (FST), an inhibitor of activin A, increased in P20 UF. We then found that FST decreased in P22 conceptuses, whereas elevated activin A found in P20 UF and endometria was further increased on P22. In addition, phosphorylated SMAD2 increased in P22 conceptuses. In bovine trophoblast cells, the treatment with P22 UF or activin An up-regulated EMT marker expressions, which were inhibited by FST. These results suggest that the initiation of bovine conceptus EMT could be regulated through the spatiotemporal expression of FST or activin A during the peri-attachment period.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

In Vivo Visualization and Characterization of Epithelial-Mesenchymal Transition in Breast Tumors.

The activation of the epithelial-to-mesenchymal transition (EMT) program is a critical step in cancer progression and metastasis, but visualization of this process at the single-cell level, especially in vivo, remains challenging. We established an in vivo approach to track the fate of tumor cells based on a novel EMT-driven fluorescent color switching breast cancer mouse model and intravital two-photon laser scanning microscopy. Specifically, the MMTV-PyMT, Rosa26-RFP-GFP, and Fsp1-Cre triple transgenic mouse model was used to monitor the conversion of RFP-positive epithelial cells to GFP-positive mesenchymal cells in mammary tumors under the control of the Fsp1 (ATL1) promoter, a gate-keeper of EMT initiation. RFP-positive cells were isolated from the tumors, sorted, and transplanted into mammary fat pads of SCID mice to monitor EMT during breast tumor formation. We found that the conversion from RFP- to GFP-positive and spindle-shaped cells was a gradual process, and that GFP-positive cells preferentially localized close to blood vessels, independent of tumor size. Furthermore, cells undergoing EMT expressed high levels of the HGF receptor, c-Met, and treatment of RFP-positive cells with the c-Met inhibitor, cabozantinib, suppressed the RFP-to-GFP conversion in vitro Moreover, administration of cabozantinib to mice with palpable RFP-positive tumors resulted in a silent EMT phenotype whereby GFP-positive cells exhibited reduced motility, leading to suppressed tumor growth. In conclusion, our imaging technique provides a novel opportunity for visualizing tumor EMT at the single-cell level and may help to reveal the intricacies underlying tumor dynamics and treatment responses. Cancer Res; 76(8); 2094-104. ©2016 AACR.

Gli1 promotes transforming growth factor-beta1– and epidermal growth factor–induced epithelial to mesenchymal transition in pancreatic cancer cells

The Hedgehog signaling pathway and its key target effector Gli1 are linked closely to the development of the epithelial to mesenchymal transition (EMT) in many cancers. The definite function of Gli1 in regulating the EMT of pancreatic cancer (PC), however, is still unclear. At the cell and tissue levels, we investigated the role of Gli1 in the initiation of EMT in PC with and without external stimulus treatments. The immunohistochemistry results showed that Gli1 was associated positively with MMP9 but not with E-cad or Vimentin. Gli1 expression was associated positively with tumor T (P=.025) and Union for International Cancer Control stage (P=.032), whereas MMP9 expression was associated positively with lymph node metastasis (P=.017) and Union for International Cancer Control stage (P=.006). Furthermore, patients with Gli1 and MMP9 coexpression had poor overall survival (P=.015). Silencing of Gli1 alone without external stimulus had no effect on EMT but inhibited transforming growth factor-beta1 (TGFβ1)- and epidermal growth factor (EGF)-induced EMT in PANC-1, AsPC-1, and BxPC-3 PC cell lines, along with the inhibition of TGFβ1- and EGF-induced EMT-like cell morphology and invasion, down-regulation of E-cad, and up-regulation of MMP9 and Vimentin in those 3 cell lines, respectively. Gli1 silencing alone has no effect on EMT initiation; however, it exerts a protumor role in the aggressive invasion of PC cells by promoting TGFβ1- and EGF-induced EMT.