Promotion Of Epithelial-mesenchymal Transition Research Articles

Sox21 Regulates Anpc10 Expression and Determines the Fate of Ectodermal Organ

Tooth and hair development initiates from ectodermal invaginations. However, the determination of organ-specific cell fates is poorly understood. The transcription factor Sox21 is expressed in the epithelium of developing teeth. The present study aimed to determine the role of Sox21 in tooth development. We found that disruption of Sox21 caused severe enamel hypoplasia, regional osteoporosis, and ectopic hair formation in the gingiva in Sox21 knockout incisors. Differentiation markers were lost in ameloblasts, which formed hair follicles expressing hair keratins. Molecular analysis and chromatin immunoprecipitation (ChIP) sequencing indicated that Sox21 regulated Anapc10, which recognizes substrates for ubiquitination-mediated degradation, and determined dental-epithelial versus hair-follicle cell fate. Disruption of either Sox21 or Anapc10 induced Smad3 expression, accelerated TGF-β1-induced promotion of epithelial-mesenchymal transition (EMT), and resulted in E-cadherin degradation via Skp2. We conclude that Sox21 disruption in the dental epithelium leads to the formation of a unique microenvironment promoting hair formation and that Sox21 controls dental epithelial differentiation and enamel formation by inhibiting EMT via Anapc10.

ZEB1 modulates endometrial receptivity through epithelial-mesenchymal transition in endometrial epithelial cells in vitro

Zinc finger E-box binding homeobox 1 (ZEB1) promotes epithelial-mesenchymal transition (EMT) in carcinogenesis, but its role in embryo implantation has not yet been identified. The present study sought to verify if ZEB1 plays a role in endometrial receptivity through regulation of EMT during embryo implantation. Endometrial epithelium from sixty patients in phase of the menstrual cycle (including proliferative and secretory phases) were collected for assessment of mRNA/protein expression. In human endometrial adenocarcinoma cell line RL95-2, ZEB1 expression was suppressed by using shRNA, and the cell function and mRNA/protein expression were evaluated. RL95-2 cells and human choriocarcinoma cell line JAR were co-cultured to establish embryo implantation model in vitro. The results showed that, ZEB1 was highly expressed at both mRNA and protein levels in human endometrium during mid-secretory phase of the menstrual cycle. Knockdown of ZEB1 expression in RL95-2 cells attenuated cell growth, migration, DNA replication, and altered expression of E-cadherin and vimentin at both mRNA and protein levels. Interestingly, knockdown of ZEB1 expression in RL95-2 cells potently suppressed JAR spheroid attachment in vitro (P < 0.01). Additionally, the. Conclusively, knockdown of ZEB1 suppressed embryo implantation in vitro, paralleled with alteration of EMT markers. ZEB1 is likely to modulate endometrial receptivity through promotion of EMT, that could be crucial for embryo implantation process.

Hepatic stellate cells promote the progression of hepatocellular carcinoma through microRNA-1246-RORα-Wnt/β-Catenin axis.

Hepatic stellate cells (HSCs) play vital roles in tumorigenesis and progression of hepatocellular carcinoma (HCC). However, there remains a lack of high-throughput studies on gene expression alterations in HCC cells in response to direct interactions with HSCs. In this study, we established a direct co-culture model of HSCs and HCC cells. We found that the expression of a set of miRNAs, most notably miR-1246, was triggered by HSCs. RORα was confirmed as the target gene of miR-1246. Either overexpression of miR-1246 or knockdown of RORα enhanced the proliferation, invasiveness, and metastatic capability of HCC both in vitro and in vivo, through Wnt/β-catenin pathway activation and promotion of epithelial-mesenchymal transition (EMT). Moreover, upregulation of miR-1246 and repression of RORα were prominent features of aggressive clinical HCC. The miR-1246-RORα-Wnt/β-catenin axis is a novel pathway through which HSCs accelerate HCC progression.

UBE2C Is Upregulated by Estrogen and Promotes Epithelial-Mesenchymal Transition via p53 in Endometrial Cancer.

Ubiquitin-conjugating enzyme E2C (UBE2C) plays important roles in tumor progression; nevertheless, its function in endometrial cancer remains unclear. This study elucidated the impact of UBE2C on endometrial cancer and its underlying mechanism. Human endometrial cancer and normal endometrial tissues were acquired from patients at Wuhan Union Hospital and UBE2C expression was detected by Western blotting and qRT-PCR. Endometrial cancer cells were transfected with a UBE2C overexpression plasmid or UBE2C-specific short hairpin RNA (shRNA) to up- or downregulate UBE2C expression, respectively. CCK8 and transwell assays were applied to assess the effects of UBE2C on cell proliferation, migration, and invasion. We found a significant elevation of UBE2C expression in patients with endometrial cancer, and that UBE2C upregulation was associated with advanced histologic grade, FIGO stage, recurrence, and shorter overall survival. UBE2C knockdown inhibited endometrial cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT), whereas UBE2C overexpression exerted the opposite effects. UBE2C downregulation increased p53 and its downstream p21 expression, with p53 overexpression reversing the EMT-promoting effects of UBE2C. UBE2C enhanced p53 ubiquitination to facilitate its degradation in endometrial cancer cells. Estradiol (E2) induced UBE2C expression via estrogen receptor α, which binds directly to the UBE2C promoter element. Silencing of UBE2C inhibited E2-promoted migration, invasion, and EMT in vitro and in vivo. IMPLICATIONS: UBE2C-mediated tumor EMT promotion by estrogen is a novel mechanism for the progression of estrogen-induced endometrial cancer, which could offer new biomarkers for diagnosis and therapy of endometrial cancer in the future.

The critical role of glucose deprivation in epithelial-mesenchymal transition in hepatocellular carcinoma under hypoxia

Imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is used to determine sites of abnormal glucose metabolism to predict high tumor grade, metastasis, and poor patient survival. However, not all tumors with increased 18F-FDG uptake show aggressive tumor biology, as evident from the moderate correlation between metastasis and high FDG uptake. We hypothesized that metastasis is likely attributable to the complexity and heterogeneity of the cancer microenvironment. To identify the cancer microenvironment that induces the epithelial-mesenchymal transition (EMT) process, tumor areas of patients with HCC were analyzed by immunostaining. Our data demonstrated the induction of EMT process in HCC cells with low proliferation under hypoxic conditions. To validate our finding, among HCC cell lines, HepG2 cells with highly increased expression of HIF1α under hypoxia were employed in vitro and in vivo. Major changes in EMT-associated protein expression, such as the up-regulation of N-cadherin and snail/slug are associated with decreased proliferation-related protein (PCNA) caused by glucose deprivation under hypoxia. Indeed, PCNA knockdown-HepG2 cells under hypoxia showed the induction of more EMT process compare to the control. Thus, HCC cells with low proliferative potential under glucose-deprived and hypoxic conditions show high probability for induced EMT process and promote cell invasion. This study investigates reasons as to why an EMT process cannot fully be predicted. Our observations indicate that rather than analyzing a single factor, an integrated analysis of hypoxia with low glucose metabolism and low cell proliferation might be helpful to predict the potential impact on induction of EMT process and promotion of cell invasion.

JNK Pathway Mediates Low Oxygen Level Induced Epithelial–Mesenchymal Transition and Stemness Maintenance in Colorectal Cancer Cells

(1) Background: Epithelial–mesenchymal transition (EMT) and cancer cell stemness maintenance (SM) are important factors for cancer metastasis. Although hypoxia has been considered as a possible factor for EMT induction and promotion of SM, studies in this area, apart from hypoxia-inducible factor (HIF) pathways and severe hypoxia, are scant. This study aimed to evaluate the effects of different oxygen levels on EMT induction and SM and elucidate the signaling pathways involved in colorectal cancer cells. (2) Methods: Cell morphological analysis, migration assay, immunofluorescence staining of cytoskeleton and Western blotting were performed on human colorectal cancer cells HT-29, DLD-1, and SW-480 cultured at 1%, 10%, and normal (21%) O2 levels. The role played by c-Jun N-terminal kinase (JNK) was evaluated through the use of the specific JNK inhibitor SP600125. (3) Results: This study evaluated 1% and 10% O2 are possible conditions for EMT induction and SM. This study also demonstrated the partial relieve of EMT induction and SM by SP600125, showing the importance of the JNK pathway in these processes. Furthermore, this study proposed a novel pathway on the regulation of Akt by JNK-c-Jun. (4) Conclusions: This study suggests 10% O2 as another possible condition for EMT induction, and SM and JNK pathways play important roles in these processes through multiple factors. Inhibition of JNK could be explored as treatment for inhibiting metastasis in colorectal cancer cells.

Deregulated bone morphogenetic proteins and their receptors are associated with disease progression of gastric cancer

Bone morphogenetic proteins (BMP) are members of the transforming growth factor β superfamily (TGF-β). BMPs are involved in tumourigenesis and disease progression of certain malignancies. To date, the role played by BMPs in gastric cancer (GC) remains largely unknown. In the present study, we systematically analysed the expression and clinical significance of BMP and BMP receptors (BMPR) in TCGA gastric cancer database and GEO database and explored the possible mechanism of action. BMP5 is reduced in gastric cancer tissues, while ACVRL1, ACVR1, TGFBR1, and BMPR2 were significantly increased in the gastric tumours. BMP3, ACVR1, TGFBR1, BMPR1B (also known as ALK6), TGFBR2 and BMPR2 were significantly associated with poorer overall survival of GC patients. A negative correlation was seen between BMP/BMPR and proliferation markers which was supported by their correlation with the cell cycle promoters and inhibitors. More interestingly, further analyses showed that BMPs and their receptors are positively correlated with matrix metalloproteinases (MMPs), epithelial mesenchymal transition (EMT) markers and stemness in GC. Furthermore, positive correlations were also frequently seen between BMP receptors and markers/regulators of angiogenesis and lymphangiogenesis in the gastric tumours. Taken together, these findings suggest that BMPs play dual roles in GC. They may inhibit proliferation of GC cells. On the other hand, they can also promote disease progression through a promotion of invasion, EMT and stemness. The elevated expression of BMP receptors in GC were also highly associated with tumour associated angiogenesis and lymphangiogenesis which facilitate tumour growth, expansion and spread.

Circ_0000267 promotes gastric cancer progression via sponging MiR-503-5p and regulating HMGA2 expression.

BackgroundCircular RNAs (circRNAs) are a class of newly discovered RNAs that attach great importance to modulate gene expression and biological function. Nonetheless, in gastric cancer (GC), the expression and function of circRNA are much less explored. In this study, circ_0000267 expression in GC was investigated and the function and mechanism of circ_0000267 was probed.Materials and MethodsQuantitative real‐time PCR (qRT‐PCR) was employed to detect circ_0000267, miR‐503‐5p, and HMGA2 expression. Immunohistochemistry and western blot were adopted to detect HMGA2 and epithelial–mesenchymal transition (EMT)‐related proteins (E‐cadherin and N‐cadherin) expression in GC tissues and cells, respectively. GC cell lines with circ_0000267 overexpressed and knocked down were constructed, and CCK‐8 assay, BrdU assay, scratch healing assay, and transwell assay were employed to assess the effect of circ_0000267 on the proliferation and metastasis of GC cells. Besides, dual‐luciferase reporter gene assay was adopted to verify the targeting relationship between circ_0000267 and miR‐503‐5p.ResultsCirc_0000267 showed a significant upregulation in GC tissues and cell lines, and its high expression level was extremely linked to the increased tumor diameter and local lymph node metastasis. Circ_0000267 overexpression accelerated GC cell proliferation, metastasis, and EMT processes, while knocking down circ_0000267 led to the opposite effect. From the perspective of mechanism, circ_0000267 promoted the progression of GC through adsorbing miR‐503‐5p and upregulating HMGA2 expression.ConclusionCirc_0000267 is an oncogenic circRNA that affects the progression of GC, which participates in promotion of GC proliferation, migration, invasion, and EMT via modulating the miR‐503‐5p/HMGA2 axis.

Tepotinib inhibits the epithelial-mesenchymal transition and tumour growth of gastric cancers via decreasing MUC5B, MMP7, and COX2

Abstract Background Aberrant expression of mucins can promote the epithelial-mesenchymal transition (EMT), which leads to enhanced tumorigenesis. Carcinogenesis-related pathways involving c-MET and β-catenin involve mucins. Among the mucins, MUC5AC and MUC6 are characteristic for stomach mucins. This study characterized expressions of MET, MUC5AC, MUC5B, and MUC6 EMT signaling in human gastric cancer (GC) cell lines, and further characterized the differential susceptibility of these cell lines to tepotinib. Methods We assessed the antitumor activity of tepotinib in GC cell lines. The effect of tepotinib on cell viability (IC50), apoptotic cell death, the EMT, and c-MET and β-catenin signaling were evaluated by MTS, flow cytometry, western blotting, and qRT-PCR. Antitumor efficacy was assessed in MKN45 xenograft mice. Results Tepotinib treatment showed dose-dependent growth inhibition of c-MET-amplified SNU620, MKN45, and KATO III cells with concomitant induction of apoptosis, but tepotinib treatment did not have an effect on c-MET-reduced MKN28 and AGS cells. Tepotinib treatment also significantly reduced expressions of phosphor-c-MET, total c-MET, phosphor-ERK, total ERK, beta-catenin, and c-MYC protein in SNU620 and MKN45 cells. In contrast, this drug was only slightly active against KATO III cells. Notably, tepotinib significantly reduced the expressions of EMT promotion genes such as MMP7, COX-2, WNT1, MUC5B, and c-MYC in c-MET-expressed GC cells, and increased expressions of EMT suppression genes such as MUC5AC, MUC6, GSK3β, and ECAD. In a murine xenograft model, tumor volumes were significantly reduced in the tepotinib-treated group, when administered by daily oral gavage at a dose of 10 mg/kg/day. Histologically, tepotinib induced more necrosis than in the control group. Conclusions These results are consistent with clinical evaluations of tepotinib in c-MET and MUC5B-expressed GCs. Editorial acknowledgement National R&D Program for Cancer Control, Ministry of Health and Welfare (HA17C0054), the National Research Foundation of Korea grant funded by the Korean Ministry of Science and ICT (NRF-2017R1A2B4005055), the Ministry of Food and Drug Safety (awarded in 2018, 18183MFDS491) of Korea, the Hallym University Medical Center Research Fund, and the Hallym University Internal Translational Research Fund (No. HURF-2015-38). Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Menin Coordinates C/EBPβ-Mediated TGF-β Signaling for Epithelial-Mesenchymal Transition and Growth Inhibition in Pancreatic Cancer

Menin displays either tumor suppression or promotion functions in a context-dependent manner. Previously, we proposed that Menin acts as a tumor suppressor by inhibiting cell growth in pancreatic ductal adenocarcinoma (PDAC), whereas the relationship between the Menin expression and overall survival rate of PDAC patients has not been completely elucidated, indicating the complexity of Menin functions in PDAC progression. Here, we identify Menin as a promoter of epithelial-mesenchymal transition (EMT), which is largely associated with cell migration or metastasis, with modest activity in cell growth inhibition. Ectopic expression of Menin suppresses the expression of CCAAT/enhancer-binding protein beta (CEBPB) and epithelial-specific genes by histone deacetylation and further enhances the TGF-β signaling-related EMT process. We also demonstrate that CCAAT/enhancer binding protein (C/EBP) beta (C/EBPβ; encoded by CEBPB) acts downstream of Menin and TGF-β signaling for balancing growth inhibition and EMT, and C/EBPβ overexpression could restore the anti-cancer functions of Menin in pancreatic cancer by cooperatively activating CDKN2A/B genes and antagonizing EMT processes. Taken together, our results suggest that Menin functions as an oncogene for cancer metastasis upon C/EBPβ depletion or acts as a tumor suppressor by cooperation with C/EBPβ to activate CDKN2A transcription.

HEG1 indicates poor prognosis and promotes hepatocellular carcinoma invasion, metastasis, and EMT by activating Wnt/β-catenin signaling.

Heart development protein with EGF-like domains 1 (HEG1) plays critical roles in embryo development and angiogenesis, which are closely related to tumor progression. However, the role of HEG1 in hepatocellular carcinoma (HCC) remains unknown. In the present study, we explored the clinical significance, biological function and regulatory mechanisms of HEG1 in HCC and found that HEG1 is significantly up-regulated in HCC cell lines and primary tumor samples. Additionally, high HEG1 expression is correlated with aggressive clinicopathological features. Patients with high HEG1 expression had shorter overall survival (OS) and disease-free survival (DFS) than those with low HEG1 expression, which indicated that HEG1 is an independent factor for poor prognosis. Lentivirus-mediated HEG1 overexpression significantly promotes HCC cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and promotes intrahepatic metastasis, lung metastasis and EMT in vivo Opposing results are observed when HEG1 is silenced. Mechanistically, HEG1 promotes β-catenin expression and maintains its stability, leading to intracellular β-catenin accumulation, β-catenin nuclear translocation and Wnt signaling activation. Loss- and gain-of-function assays further confirmed that β-catenin is essential for HEG1-mediated promotion of HCC invasion, metastasis and EMT. In conclusion, HEG1 indicates poor prognosis; plays important roles in HCC invasion, metastasis and EMT by activating Wnt/β-catenin signaling; and can serve as a potentially valuable prognostic biomarker and therapeutic target for HCC.

MiR-185 affected the EMT, cell viability, and proliferation via DNMT1/MEG3 pathway in TGF-β1-induced renal fibrosis.

Kidney fibrosis is usually the final manifestation of a wide variety of renal diseases. Recent years, research reported that long non-coding RNAs (lncRNAs) played important roles in a variety of human diseases. However, the role and underlying mechanisms of lncRNAs in kidney fibrosis were complicated and largely unclear. In our study, we constructed the cell model of renal fibrosis in HK2 cells using transforming growth factor β1 (TGF-β1) and found that lncRNA maternally expressed gene 3 (MEG3) was downregulated in TGF-β1-induced renal fibrosis. We then found that overexpressed MEG3 inhibited the TGF-β1-induced promotion of epithelial-mesenchymal transition, cell viability, and proliferation. Furthermore, we demonstrated that DNA methyltransferases 1 (DNMT1) regulated the MEG3 expression by altering the CpGs methylation level of MEG3 promoter in TGF-β1-induced renal fibrosis. In addition, we further revealed that miR-185 could regulate the DNMT1 expression and thus, modulate the MEG3 in TGF-β1-induced renal fibrosis. Ultimately, our study illustrated that the modulation of the miR-185/ DNMT1/ MEG3 pathway exerted important roles in TGF-β1-induced renal fibrosis. In summary, our finding displayed a novel regulatory mechanism for TGF-β1-induced renal fibrosis, which provided a new potential therapeutic target for renal fibrosis.

STC2 Is a Potential Prognostic Biomarker for Pancreatic Cancer and Promotes Migration and Invasion by Inducing Epithelial-Mesenchymal Transition.

Aberrant expression of stanniocalcin 2 (STC2) is implicated in cancer development. STC2 acts as a tumor promoter to drive some cancers. However, its contribution to the development of pancreatic cancer remains unclear. This study showed that the expression of STC2 was significantly upregulated in pancreatic cancer tissues. Moreover, its expression was positively correlated with tumor size and lymph node metastasis and negatively correlated with 5-year survival rate of pancreatic cancer patients. Additionally, the expression levels of STC2 were a novel biomarker for predicting overall survival rate after surgery. Furthermore, overexpression of STC2 could promote the proliferation, migration, and invasion of pancreatic cancer cell lines, while knocking down of STC2 led to antiproliferation and antimetastasis activities. Further mechanistic investigations revealed that the expression of STC2 could significantly promote the epithelial–mesenchymal transition (EMT) in pancreatic cancer cells. These data indicated that the overexpression of STC2 in pancreatic cancer contributes to the metastasis through the promotion of EMT, suggesting that STC2 is a potential prognostic biomarker and therapeutic target for pancreatic cancer.

Abstract SY28-04: Obesity-associated leptin signaling promotes chemotherapy resistance in triple-negative breast cancer: The role of tumor-initiating cell enrichment

Abstract SY28-04: Obesity-associated leptin signaling promotes chemotherapy resistance in triple-negative breast cancer: The role of tumor-initiating cell enrichment

Abstract 1039: c-Met activation promotes epithelial-to-mesenchymal transition (EMT) in renal cancer cells through the upregulation of the chemokine receptor CXCR7

Abstract Purpose: The purpose of this study is to explore how the receptor tyrosine kinase (RTK) c-Met modulates the expression of the pro-tumorigenic molecule CXCR7, a chemokine receptor, in renal cancer cells; and to investigate the role of c-Met and CXCR7 in promoting the epithelial-mesenchymal transition (EMT) of renal cancer cells. Background: c-Met, a pro-oncogenic RTK, can play a major role in the survival and progression of cancer cells; and it is often overexpressed in both clear cell and papillary renal cell carcinoma (RCC). c-Met, upon activation by its specific ligand hepatocyte growth factor (HGF), can induce a broad spectrum of biological pathways involved in the growth of cancer cells. CXCR family of chemokine receptors and their chemokine ligands were shown to exhibit decisive roles in tumor initiation, promotion, progression, and metastasis. CXCR7 is upregulated in several types of cancers, including renal cancer, and found to be involved in tumor cell development, survival, and metastasis. A global process integral to the cancer metastasis is EMT, which results in the disruption of cell-to-cell junctions and endows epithelial cells with the ability to migrate and invade surrounding tissue. EMT process is associated with an increase of mesenchymal markers like vimentin and a decrease of epithelial markers like E-cadherin in cancer cells. Sustained activation of c-Met induces EMT in renal cancer cells, however, the cross-talk between CXCR7 and c-Met signaling in the promotion of renal cancer EMT remains unclear. Results: We assessed the expression levels of CXCR7 by Western blot analysis and found that CXCR7 is overexpressed in human renal cancer cells (both 786-O and ACHN) when compared to normal renal epithelial cells (RPTEC). Also, in both 786-O and ACHN cells, HGF-induced activation of c-Met further increased the expression of CXCR7 at both RNA and protein levels. In renal cancer cells (both 786-O and ACHN), siRNA-mediated knockdown of c-Met or treatment with XL-184 (a small molecule inhibitor of c-Met) inhibited c-Met-induced upregulation of CXCR7. c-Met activation increased the expression of pro-EMT markers such as vimentin, N-cadherin, and MMP-9 and suppressed the expression of anti-EMT molecule E-cadherin, as measured by Western blot and flow cytometry. On the other hand, siRNA-mediated silencing of CXCR7 attenuated the induction of EMT, suggesting that CXCR7 plays a major role in c-Met-induced EMT in renal cancer cells. Conclusion: Together, our findings demonstrate that the c-Met-CXCR7 axis can trigger the EMT, which can play an important role(s) in renal cancer proliferation and migration. Citation Format: Samik Chakraborty, Murugabaskar Balan, Soumitro Pal. c-Met activation promotes epithelial-to-mesenchymal transition (EMT) in renal cancer cells through the upregulation of the chemokine receptor CXCR7 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1039.

Roles of the Phosphorylation of Transcriptional Factors in Epithelial-Mesenchymal Transition.

Epithelial-to-mesenchymal transition (EMT) is the first step in the development of the invasive and migratory properties of cancer metastasis. Since the transcriptional reprogramming of a number of genes occurs in EMT, the regulation of EMT transcription factors has been intensively investigated. EMT transcriptional factors are commonly classified by the direct or indirect repression of E-cadherin because one of hallmarks of EMT is the loss of E-cadherin. This facilitates the expression of genes for EMT, tumor invasion, and metastasis. The posttranslational modification of EMT transcriptional factors, such as Snail and Slug, directly regulates their functions, including their stability, nuclear localization, protein-protein interaction, and ubiquitination for the promotion or termination of EMT at the specific points. Here, we discuss how posttranslational modifications regulate gene expression in a dynamic and reversible manner by modifying upstream signaling pathways, focusing in particular on the posttranslational modifications of Snail, Slug, ZEB1, ZEB2, and TWIST1. This review demonstrates that EMT transcription factors regulate metastasis through their posttranslational modifications and that the flexibility and reversibility of EMT can be modified by phosphorylation.

PTPRB promotes metastasis of colorectal carcinoma via inducing epithelial-mesenchymal transition

Dysregulation of protein tyrosine phosphatase, receptor type B (PTPRB) correlates with the development of a variety of tumors. Here we show that PTPRB promotes metastasis of colorectal cancer (CRC) cells via inducing epithelial-mesenchymal transition (EMT). We find that PTPRB is expressed at significantly higher levels in CRC tissues compared to adjacent nontumor tissues and in CRC cell lines with high invasion. PTPRB knockdown decreased the number of invasive CRC cells in an in vitro wound healing model, and also reduced tumor metastasis in vivo. Conversely, PTPRB overexpression promoted CRC cell invasion in vitro and metastasis in vivo. PTPRB overexpression decreased vimentin expression and promoted E-cadherin expression, consistent with promotion of EMT, while PTPRB knockdown had the opposite effect. Hypoxic conditions induced EMT and promoted invasion in CRC cells, but these effects were eliminated by PTPRB knockdown. EMT blockade via TWIST1 knockdown inhibited the migration and invasiveness of CRC cells, and even increased PTPRB expression could not reverse this effect. Altogether, these data support the conclusion that PTPRB promotes invasion and metastasis of CRC cells via inducing EMT, and that PTPRB would be a novel therapeutic target for the treatment of CRC.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition.

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors. In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Apolipoprotein M could inhibit growth and metastasis of SMMC7721 cells via vitamin D receptor signaling.

Objective: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high mortality-to-incidence ratios. Apolipoprotein M (ApoM), a member of the apolipoprotein family, is mainly synthesized in the liver, whereas its role in HCC has not been elucidated. Here, we examined the effect of ApoM on the biological behavior of HCC cells and the possible mechanisms.Methods: We used CRISPR/Cas9 technology to knock out ApoM in SMMC7721 cells. Differentially expressed genes before and after ApoM knockout (KO) were analyzed by GeneChip microarrays and confirmed by qRT-PCR. Cell assays of proliferation, apoptosis, migration and invasion were performed in SMMC7721 cells, and the expression of epithelial–mesenchymal transition (EMT) markers was performed by western blot. And we performed functional recovery experiments by overexpressing vitamin D receptor (VDR) in SMMC7721.Results: The ApoM-KO SMMC7721 cell line was successfully constructed using the CRISPR/Cas9 technology. Our results showed that silencing ApoM suppressed apoptosis and promoted proliferation, migration, invasion and EMT of SMMC7721 cells. The microarray data revealed that a total of 1,868 differentially expressed genes were identified, including VDR. The qRT-PCR and western blot verification results demonstrated that knocking out ApoM could significantly reduce the expression of VDR. The functional recovery experiments indicated that VDR overexpression could offset the inhibition of cell apoptosis and the promotion of cell proliferation, migration, invasion and EMT caused by knocking out ApoM in SMMC7721 cells.Conclusion: ApoM could function as a tumor suppressor to inhibit the growth and metastasis of SMMC7721 cells via VDR signaling in HCC.

ACOT12-Dependent Alteration of Acetyl-CoA Drives Hepatocellular Carcinoma Metastasis by Epigenetic Induction of Epithelial-Mesenchymal Transition

Metabolic reprogramming plays an important role in supporting tumor growth. However, little is known about the metabolic alterations that promote cancer metastasis. In this study, we identify acyl-CoA thioesterase 12 (ACOT12) as a key player in hepatocellular carcinoma (HCC) metastasis. The expression of ACOT12 is significantly down-regulated in HCC tissues and is closely associated with HCC metastasis and poor survival of HCC patients. Gain- and loss-of-function studies demonstrate that ACOT12 suppresses HCC metastasis both invitro and invivo. Further mechanistic studies reveal that ACOT12 regulates the cellular acetyl-CoA levels and histone acetylation in HCC cells and that down-regulation of ACOT12 promotes HCC metastasis by epigenetically inducing TWIST2 expression and the promotion of epithelial-mesenchymal transition. Taken together, our findings link the alteration of acetyl-CoA with HCC metastasis and imply that ACOT12 could be a prognostic marker and a potential therapeutic target for combating HCC metastasis.