Epithelial–mesenchymal transition in human cancer: Comprehensive reprogramming of metabolism, epigenetics, and differentiation

High Expression of ITGA3 Promotes Proliferation and Cell Cycle Progression and Indicates Poor Prognosis in Intrahepatic Cholangiocarcinoma

Integrin subunit alpha 3 (ITGA3) interacts with a beta 1 subunit to form a member of the integrin family. Integrins are heterodimeric integral membrane proteins that serve as cell surface adhesion proteins. In this research, we investigated the biological function of this protein in human intrahepatic cholangiocarcinoma (ICC) for the first time. Here, using Western blotting and immunohistochemistry assays, we discovered that ITGA3 was overexpressed in ICC cell lines and ICC patients. Moreover, we found ITGA3 expression correlated with several clinicopathological features, including tumor size, lymph node metastasis, and the TNM stage. Patients with high ITGA3 expression underwent a worse prognosis after complete resection compared with patients with low ITGA3 expression in terms of overall survival. Furthermore, we demonstrated that ITGA3 could significantly promote ICC cell proliferation and cell cycle progression in vitro. However, as a classical cell surface adhesion molecule, we found ITGA3 correlated negatively with the migration and invasion of ICC cell lines, which differs from other malignant tumors. Generally, these findings suggest that ITGA3 may play a role as a potential oncogene in ICC and suppression of ITGA3 expression may establish a novel target for guiding the therapy of ICC patients.

Mixed lineage kinase ZAK promotes epithelial-mesenchymal transition in cancer progression

ZAK, a mixed lineage kinase, is often described as a positive or negative regulator of cell growth. We identified it as one of the top hits in our kinome cDNA screen for potent regulators of epithelial mesenchymal transition (EMT). Ectopic expression of ZAK promoted EMT phenotypes and apoptosis resistance in multiple epithelial cell lines, while having different impacts on cell growth in different cell lines. Conversely, depletion of ZAK in aggressive mesenchymal cancer cells reversed EMT phenotypes, increased sensitivity to conventional cytotoxic drugs, and attenuated bone metastasis potential, with little impact on primary tumor growth. Mechanistically, ZAK-mediated EMT is associated with activation of ZEB1 and suppression of epithelial splicing regulatory proteins (ESRPs), which results in a switch in CD44 expression from the epithelial CD44v8-9 isoform to the mesenchymal CD44s isoform. Of note, transcriptomic analysis showed that ZAK overexpression is significantly associated with poor survival in a number of human cancer types. Tissue microarray analysis on breast invasive carcinoma further supported that ZAK overexpression is an independent poor prognostic factor for overall survival in breast cancer. Through combination with ZAK, prognostic accuracy of other common clinicopathological markers in breast cancer is improved by up to 21%. Taken together, these results suggest that promoting EMT is the primary role for ZAK in cancer progression. They also highlight its potential as a biomarker to identify high-risk patients, and suggest its promise as a therapeutic target for inhibiting metastasis and overcoming drug resistance.

Na+/H+ exchanger NHE1 regulation modulates metastatic potential and epithelial-mesenchymal transition of triple-negative breast cancer cells

In triple-negative breast cancer (TNBC), the high recurrence rate, increased invasion and aggressive metastatic formation dictate patient survival. We previously demonstrated a critical role for the Na+/H+ exchanger isoform 1 (NHE1) in controlling metastasis of triple-negative cells. Here, we investigated the effect of changes to three regulatory loci of NHE1. Two via the Ras/Raf/ERK/p90RSK pathway: p90RSK/14-3-3 (S703A) and ERK1/2 (S766,770,771A, SSSA) and a third via a calmodulin-binding domain (K641,R643,645,647E, 1K3R4E). MDA-MB-231 cells with a mutation at the p90RSK site (S703A-NHE1) changed from a wild-type mesenchymal morphology to a smaller epithelial-like phenotype with a loss of expression of mesenchymal marker vimentin. S703A cells also had reduced metastatic potential and markedly decreased rates of migration, invasion, spheroid growth, anchorage-dependent and soft agar colony formation. Similarly, BI-D1870, a specific inhibitor of p90RSK, significantly inhibited the metastatic potential of highly invasive MDA-MB-231 and moderately invasive MDA-MB-468 TNBC cells, but was minimally effective in non-invasive Hs578T TNBC cells. In contrast, invasion and spheroid growth were unaffected in cells containing NHE1 with mutations interfering with its activation by ERK1/2 (SSSA), though rates of migration and colony formation were reduced. Cells with a constitutive activation of NHE1 via the 1K3R4E mutation exhibited higher rates of migration, invasion, and spheroid growth. Taken together, our data demonstrate the critical role of NHE1 in metastasis, and suggest a novel link between NHE1 and the expression and cytosolic organization of vimentin, a key factor in epithelial-mesenchymal transition, that is dependent on p90RSK/14-3-3-mediated activation of the exchanger.

GP73 promotes invasion and metastasis of bladder cancer by regulating the epithelial-mesenchymal transition through the TGF-β1/Smad2 signalling pathway

This study investigated the effects of Golgi membrane protein 73 (GP73) on the epithelial-mesenchymal transition (EMT) and on bladder cancer cell invasion and metastasis through the TGF-β1/Smad2 signalling pathway. Paired bladder cancer and adjacent tissue samples (102) and normal bladder tissue samples (106) were obtained. Bladder cancer cell lines (T24, 5637, RT4, 253J and J82) were selected and assigned to blank, negative control (NC), TGF-β, thrombospondin-1 (TSP-1), TGF-β1+ TSP-1, GP73-siRNA-1, GP73-siRNA-2, GP73-siRNA-1+ TSP-1, GP73-siRNA-1+ pcDNA-GP73, WT1-siRNA and WT1-siRNA + GP73-siRNA-1 groups. Expressions of GP73, TGF-β1, Smad2, p-Smad2, E-cadherin and vimentin were detected using RT-qPCR and Western blotting. Cell proliferation, migration and invasion were determined using MTT assay, scratch testing and Transwell assay, respectively. Compared with the blank and NC groups, levels of GP73, TGF-β1, Smad2, p-Smad2, N-cadherin and vimentin decreased, and levels of WT1 and E-cadherin increased in the GP73-siRNA-1 and GP73-siRNA-2 groups, while the opposite results were observed in the WT1 siRNA, TGF-β, TSP-1 and TGF-β + TSP-1 groups. Cell proliferation, migration and invasion notably decreased in the GP73-siRNA-1 and GP73-siRNA-2 groups in comparison with the blank and NC groups, while in the WT1 siRNA, TGF-β, TSP-1 and TGF-β + TSP-1 groups, cell migration, invasion and proliferation showed the reduction after the EMT. These results suggest that GP73 promotes bladder cancer invasion and metastasis by inducing the EMT through down-regulating WT1 levels and activating the TGF-β1/Smad2 signalling pathway.

IFN-α potentiates the direct and immune-mediated antitumor effects of epigenetic drugs on both metastatic and stem cells of colorectal cancer

Epigenetic alterations, including dysregulated DNA methylation and histone modifications, govern the progression of colorectal cancer (CRC). Cancer cells exploit epigenetic regulation to control cellular pathways, including apoptotic and metastatic signals. Since aberrations in epigenome can be pharmacologically reversed by DNA methyltransferase and histone deacetylase inhibitors, epigenetics in combination with standard agents are currently envisaged as a new therapeutic frontier in cancer, expected to overcome drug resistance associated with current treatments. In this study, we challenged this idea and demonstrated that the combination of azacitidine and romidepsin with IFN-α owns a high therapeutic potential, targeting the most aggressive cellular components of CRC, such as metastatic cells and cancer stem cells (CSCs), via tight control of key survival and death pathways. Moreover, the antitumor efficacy of this novel pharmacological approach is associated with induction of signals of immunogenic cell death. Of note, a previously undisclosed key role of IFN-α in inducing both antiproliferative and pro-apoptotic effects on CSCs of CRC was also found. Overall, these findings open a new frontier on the suitability of IFN-α in association with epigenetics as a novel and promising therapeutic approach for CRC management.

Study on Attenuating Angiogenesis and Epithelial-Mesenchymal Transition (EMT) of Non-Small Cell Lung Carcinoma (NSCLC) by Regulating MAGEC2

OBJECTIVE

To investigate the role of MAGE family member C2 in angiogenesis and epithelial-mesenchymal transition of non-small cell lung carcinoma.

METHODS

The Cancer Genome Atlas data set was analyzed to filter the highly expressed gene melanoma antigen family C2 in non-small cell lung carcinoma. Quantitative reverse transcription-polymerase chain reaction was performed to verify the overexpression of melanoma antigen family C2 in non-small cell lung carcinoma cell lines. Melanoma antigen family C2 complementary DNA and short hairpin RNA (shRNA) were transfected into SK-MES-1 cells to regulate melanoma antigen family C2 expression. Cell Counting Kit-8 assay, flow cytometry, wound healing assay, and Transwell assay were performed to investigate the effect of melanoma antigen family C2 on proliferation, apoptosis, migration, and invasion of SK-MES-1 cell line. Western blot was used to detect the expression of epithelial-mesenchymal transition markers. Enzyme-linked immunosorbent assay was performed to investigate the secretion of vascular endothelial growth factor, and tube formation assay was conducted to explore the effect of melanoma antigen family C2 on angiogenesis ability of the tumor. Tumor xenograft on nude mice and immunohistochemical/hematoxylin and eosin staining were also performed to detect the influence of melanoma antigen family C2 on growth and metastasis of non-small cell lung carcinoma cells.

RESULTS

Melanoma antigen family C2 was highly expressed in non-small cell lung carcinoma cells; melanoma antigen family C2 promoted the expression of epithelial-mesenchymal transition-related proteins as well as enhance the secretion of vascular endothelial growth factor and promote angiogenesis; melanoma antigen family C2 promoted proliferation, migration, and invasion and suppressed apoptosis of non-small cell lung carcinoma cells. It could also facilitate growth and metastasis of non-small cell lung carcinoma in vivo.

CONCLUSION

Melanoma antigen family C2 was a critical factor of angiogenesis and epithelial-mesenchymal transition in non-small cell lung carcinoma.

Long noncoding RNA LINC00978 promotes cancer growth and acts as a diagnostic biomarker in gastric cancer

OBJECTIVES

Long noncoding RNAs (lncRNAs) play important roles in cancer development and progression. The deregulated expression of LINC00978 has been reported in human cancers. However, the expression pattern and biological roles of LINC00978 in gastric cancer (GC) remain unclear. In this study, we investigated the potential roles and clinical value of LINC00978 in gastric cancer.

MATERIALS AND METHODS

QRT-PCR was performed to investigate the expression of LINC00978 in gastric cancer cell lines, tissues and serum samples. Cell counting, colony formation, transwell migration and matrigel invasion assays were performed to determine the effects of shRNA-mediated knockdown of LINC00978 on gastric cancer cell functions. In vivo tumour growth assay was also conducted. Flow cytometry, immunohistochemistry, western blot and qRT-PCR were used for potential mechanism study.

RESULTS

LINC00978 expression level was elevated in GC tumour tissues, serum samples and cell lines. The expression level of LINC00978 was significantly correlated with tumour size (P = 0.02), lymphatic metastasis (P = 0.009) and TNM stage (P = 0.009). LINC00978 knockdown inhibited the proliferation of GC cells by suppressing cell cycle progression and inducing apoptosis. LINC00978 knockdown also inhibited the migration and invasion of GC cells. In addition, LINC00978 knockdown inhibited the activation of TGF-β/SMAD signalling pathway and the process of epithelial-mesenchymal transition (EMT) in GC cells. Moreover, the in vivo tumorigenicity of LINC00978 knockdown GC cells in mice was significantly decreased.

CONCLUSIONS

LINC00978 promotes gastric cancer progression and may serve as a potential biomarker for GC.

Loss of LKB1 Expression Decreases the Survival and Promotes Laryngeal Cancer Metastasis

Background: Given recent results indicating that diminished LKB1 expression in laryngeal cancer correlates with shorter survival. We aim to perform an analysis estimate the role of decreased liver kinase B1(LKB1) and in the prognostication of human laryngeal squamous cell carcinoma (LSCC). Methods: We conducted a retrospective study and evaluate the expression of LKB1 and p16INK4a (p16) in 208 clinical advanced-stage LSCC tissue samples by using immunohistochemistry. The specimens were received at Sun Yat-sen University Cancer Center (Guangzhou, China). To evaluate the independent prognostic relevance of LKB1, univariate and multivariate Cox regression models were used, overall survival (OS) and distant metastasis-free survival (DMFS) were compared using the Kaplan-Meier method. Results: Immunohistochemical analyses revealed that 80/208 (38.5%) of the LSCC tissue samples expressed high LKB1. Low LKB1 expression was associated with a significantly shorter OS and DMFS than high LKB1 expression (P = 0.041 and 0.028, respectively; log-rank test), and there was a poorer OS in the p16-positive than p16-negative group. In the subgroup stratified by p16 status, the shorter OS were also seen with low LKB1 expression. Multivariate survival analysis indicated that high LKB1 expression was an independent prognostic factor for OS (hazard ratio [HR]: 1.628, 95% confidence interval [CI]: 1.060-2.500, P = 0.026) and DMFS (HR: 2.182, 95% CI: 1.069-4.456, P = 0.032). Conclusions: Our data indicated that low expression of LKB1 was significantly associated with poor prognosis and it may represent a marker of tumor metastasis in patients with LSCC. When combined with p16, LKB1 was also of prognostic value.

Tumorigenesis as a process of gradual loss of original cell identity and gain of properties of neural precursor/progenitor cells

Cancer is a complex disease without a unified explanation for its cause so far. Our recent work demonstrates that cancer cells share similar regulatory networks and characteristics with embryonic neural cells. Based on the study, I will address the relationship between tumor and neural cells in more details. I collected the evidence from various aspects of cancer development in many other studies, and integrated the information from studies on cancer cell properties, cell fate specification during embryonic development and evolution. Synthesis of the information strongly supports that cancer cells share much more similarities with neural progenitor/stem cells than with mesenchymal-type cells and that tumorigenesis represents a process of gradual loss of cell or lineage identity and gain of characteristics of neural cells. I also discuss cancer EMT, a concept having been under intense debate, and possibly the true meaning of EMT in cancer initiation and development. This synthesis provides fresh insights into a unified explanation for and a previously unrecognized nature of tumorigenesis, which might not be revealed by studies on individual molecular events. The review will also present some brief suggestions for cancer research based on the proposed model of tumorigenesis.

Antcin-H Isolated from Antrodia cinnamomea Inhibits Renal Cancer Cell Invasion Partly through Inactivation of FAK-ERK-C/EBP-β/c-Fos-MMP-7 Pathways

Antcin-H, a natural triterpene, is purified from a famous anticancer medicinal mushroom, Antrodia cinnamomea, in Taiwan. This study showed that antcin-H inhibited the growth of human renal carcinoma 786-0 cells; the IC₅₀ value (for 48 h) was 170 μM. Besides, the migration and invasion of 786-0 cells were suppressed by antcin-H under noncytotoxic concentrations (<100 μM); these events were accompanied by inhibition of FAK and Src kinase activities, decrease of paxillin phosphorylation, impairment of lamellipodium formation, and upregulation of TIMPs and downregulation of MMPs, especially MMP-7 expression. Luciferase reporter assay showed that antcin-H repressed the MMP-7 promoter activity, in parallel to inhibiting c-Fos/AP-1 and C/EBP-β transactivation abilities. Moreover, antcin-H suppressed the activity of ERK1/2 and decreased the binding ability of C/EBP-β and c-Fos on the upstream/enhancer region of MMP-7 promoter. Overall, this study demonstrated that the anti-invasive effect of antcin-H in human renal carcinoma 786-0 cells might be at least in part by abrogating focal adhesion complex and lamellipodium formation through inhibiting the Src/FAK-paxillin signaling pathways and decreasing MMP-7 expression through suppressing the ERK1/2-AP-1/c-Fos and C/EBP-β signaling axis. Our findings provide the evidence that antcin-H may be an active component existing in A. cinnamomea with anticancer effect.

MicroRNA-34a targets epithelial to mesenchymal transition-inducing transcription factors (EMT-TFs) and inhibits breast cancer cell migration and invasion

MicroRNA-34a (miR-34a) plays an essential role against tumorigenesis and progression of cancer metastasis. Here, we analyzed the expression, targets and functional effects of miR-34a on epithelial to mesenchymal transition-inducing transcription factors (EMT-TFs), such as TWIST1, SLUG and ZEB1/2, and an EMT-inducing protein NOTCH1 in breast cancer (BC) cell migration and invasion and its correlation with tumorigenesis and clinical outcomes. Expression of miR-34a is downregulated in human metastatic breast cancers (MBC) compared to normal breast tissues and is negatively correlated with clinicopathological features of MBC patients. Ectopic expression of miR-34a in MBC cell-line BT-549 significantly inhibits cell migration and invasion, but exhibits no clear effect on BC cell growth. We found that miR-34a is able to inactivate EMT signaling pathway with mediatory of NOTCH1, TWIST1, and ZEB1 upon 3′-UTR activity in MBC cell lines, but has no inhibitory effects on SLUG and ZEB2. Furthermore, we investigated the synergistic effects of Thymoquinone (TQ) and miR-34a together on the expression of EMT-associated proteins. Results showed that co-delivery of miR-34a and TQ is able to inactivate EMT signaling pathway by directly targeting TWIST1 and ZEB1 in BT-549 cell line, indicating that they might be a promising therapeutic combination against breast cancer metastasis. Epigenetic inactivation of the EMT-TFs/miR-34a pathway can potentially alter the equilibrium of these regulations, facilitating EMT and metastasis in BC. Altogether, our findings suggest that miR-34a alone could serve as a potential therapeutic agent for MBC, and together with TQ, their therapeutic potential is synergistically enhanced.

The M6A methyltransferase METTL3: acting as a tumor suppressor in renal cell carcinoma

We aimed to study the role of METTL3 in renal cell carcinoma (RCC) carcinogenesis and development. Immunohistochemistry was performed in clinical tissue microarray. Expression level of METTL3 in RCC tissues and cell lines was evaluated by quantitative real-time PCR (qRT-PCR) and western blot. Then, the effects of METTL3 on proliferation, migration, invasion and cell cycle were studied in RCC cells. Additionally, in vivo study was carried out in nude mice. Negative METTL3 expression was associated with larger tumor size (P=0.010) and higher histological grade (P=0.021). Moreover, RCC patients with positive METTL3 expression had an obvious longer survival time (P=0.039). METTL3 mRNA and protein expression was lower in RCC samples compared with adjacent non-tumor samples, and lower in RCC cell lines (CAKI-1, CAKI-2 and ACHN) compared with HK-2. Afterwards, knockdown of METTL3 could obviously promote cell proliferation, migration and invasion function, and induce G0/G1 arrest. In contrast, up-regulation of METTL3 could inhibit such functions and reduce G0/G1 arrest. Additionally, up-regulation of METTL3 significantly suppressed tumor growth in vivo. Furthermore, significant changes in epithelial-to-mesenchymal transition (EMT) and PI3K-Akt-mTOR pathways were observed. Overall, our findings demonstrated that METTL3 might have a carcinostasis role in cell proliferation, migration, invasion function and cell cycle of RCC, indicating METTL3 may act as a novel marker for tumorigenesis, development and survival of RCC.

Bioorthogonal chemical imaging of metabolic changes during epithelial-mesenchymal transition of cancer cells by stimulated Raman scattering microscopy

Study of metabolic changes during epithelial-mesenchymal transition (EMT) of cancer cells is important for basic understanding and therapeutic management of cancer progression. We here used metabolic labeling and stimulated Raman scattering (SRS) microscopy, a strategy of bioorthogonal chemical imaging, to directly visualize changes in anabolic metabolism during cancer EMT at a single-cell level. MCF-7 breast cancer cell is employed as a model system. Four types of metabolites (amino acids, glucose, fatty acids, and choline) are labeled with either deuterium or alkyne (C≡C) tag. Their intracellular incorporations into MCF-7 cells before or after EMT are visualized by SRS imaging targeted at the signature vibration frequency of C-D or C≡C bonds. Overall, after EMT, anabolism of amino acids, glucose, and choline is less active, reflecting slower protein and membrane synthesis in mesenchymal cells. Interestingly, we also observed less incorporation of glucose and palmitate acids into membrane lipids, but more of them into lipid droplets in mesenchymal cells. This result indicates that, although mesenchymal cells synthesize fewer membrane lipids, they are actively storing energy into lipid droplets, either through de novo lipogenesis from glucose or direct scavenging of exogenous free fatty acids. Hence, metabolic labeling coupled with SRS can be a straightforward method in imaging cancer metabolism.

Metabolic Comparison of Dorsal versus Ventral Cells Directly in the Live 8-cell Frog Embryo by Microprobe Single-cell CE-ESI-MS

Single-cell mass spectrometry (MS) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. Using whole-cell dissection and capillary electrophoresis electrospray ionization (CE-ESI) MS, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the South African clawed frog (Xenopus laevis), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis of the 8-cell embryo. Here, we tested this hypothesis directly in the live embryo by quantifying single-cell metabolism between the left dorsal-animal (D1L) and left ventral-animal (V1L) cell pairs in the same embryo using microprobe single-cell CE-ESI-MS in the positive ion mode. After quantifying ~70 molecular features, including 52 identified metabolites, that were reproducibly detected in both cells among n = 5 different embryos, we employed supervised multivariate data analysis based on partial least squares discriminant analysis (PLSDA) to compare metabolism between the cell types. Statistical analysis revealed that asparagine, glycine betaine, and a yet-unidentified molecule were statistically significantly enriched in the D1L cell compared to V1L (p < 0.05 and fold change ≥ 1.5). These results demonstrate that cells derived from the same hemisphere (animal pole) harbor different metabolic activity along the dorsal-ventral axis as early as the 8-cell stage. Apart from providing new evidence of metabolic cell heterogeneity during early embryogenesis, this study demonstrates that microprobe single-cell CE-ESI-MS enables the analysis of multiple single cells in the same live vertebrate embryo.

CUL4B promotes bladder cancer metastasis and induces epithelial-to-mesenchymal transition by activating the Wnt/β-catenin signaling pathway

Increased expression of cullin 4B (CUL4B) is linked to progression in several cancers. This study aims to explore the effects of CUL4B on bladder cancer (BC) metastasis and epithelial-to-mesenchymal transition (EMT) and potential correlation to the Wnt/β-catenin signaling pathway. We collected BC tissues and adjacent normal tissues from 124 BC patients. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were employed in order to detect the expression of Wnt/β-catenin signaling pathway-related proteins and EMT markers. MTT and Transwell assays were used in order to measure cell proliferation, migration, and invasion. BC 5637 cells were transfected with control, siRNA scramble control (siRNA-NC), si-CUL4B, and CUL4B or Wnt inhibitory factor 1 (WIF-1) overexpression constructs. Levels of CUL4B mRNA and protein were increased in BC tissues in comparison with the adjacent normal tissues. CUL4B expression was negatively correlated with the expression of E-cadherin and positively correlated to the expression of N-cadherin and Vimentin. Compared to the control group, levels of β-catenin, cyclinD1, c-myc, MMP7, and EMT markers were reduced, whereas phosphorylated GSK3β^Ser9 and E-cadherin levels were increased in the si-CUL4B and WIF-1 groups. In addition, cell proliferation, migration, and invasion abilities were also increased. Increasing CUL4B expression had the opposite effect. These findings suggest that CUL4B induces EMT and promotes metastasis of BC by activating the Wnt/β-catenin signaling pathway.

Cellular glycosylation senses metabolic changes and modulates cell plasticity during epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is a developmental program reactivated by tumor cells that leads to the switch from epithelial to mesenchymal phenotype. During EMT, cells are transcriptionally regulated to decrease E-cadherin expression while expressing mesenchymal markers such as vimentin, fibronectin, and N-cadherin. Growing body of evidences suggest that cells engaged in EMT undergo a metabolic reprograming process, redirecting glucose flux toward hexosamine biosynthesis pathway (HBP), which fuels aberrant glycosylation patterns that are extensively observed in cancer cells. HBP depends on nutrient availability to produce its end product UDP-GlcNAc, and for this reason is considered a metabolic sensor pathway. UDP-GlcNAc is the substrate used for the synthesis of major types of glycosylation, including O-GlcNAc and cell surface glycans. In general, the rate limiting enzyme of HBP, GFAT, is overexpressed in many cancer types that present EMT features as well as aberrant glycosylation. Moreover, altered levels of O-GlcNAcylation can modulate cell morphology and favor EMT. In this review, we summarize some of the current knowledge that correlates glucose metabolism, aberrant glycosylation and hyper O-GlcNAcylation supported by HBP that leads to EMT activation. Developmental Dynamics 247:481-491, 2018. © 2017 Wiley Periodicals, Inc.

Ginsenoside Rb1 inhibits hypoxia-induced epithelial-mesenchymal transition in ovarian cancer cells by regulating microRNA-25

Metastasis frequently occurs in advanced ovarian cancer, which not only leads to substantial mortality but also becomes a major challenge to effective treatment. Epithelial-mesenchymal transition (EMT) is a key mechanism facilitating cancer metastasis. Targeting the EMT process with more efficacious and less toxic agents to prevent metastasis is of significant therapeutic value for ovarian cancer treatment. The anti-EMT function and mechanism of ginsenoside Rb1, a monomer composition extracted from the traditional Chinese herb Panax ginseng or P. notoginseng, was investigated in the present study. Western blotting demonstrated that treatment with ginsenoside Rb1 antagonized hypoxia-induced E-cadherin downregulation and vimentin upregulation in SKOV3 and 3AO human ovarian cancer cells. Wound healing assays and in vitro migration assays indicated that ginsenoside Rb1 weakened hypoxia-enhanced cell migration ability. Furthermore, it was demonstrated that microRNA (miR)-25 is upregulated by hypoxia in ovarian cancer cells, which was attenuated by ginsenoside Rb1 treatment. Additionally, forced expression of miR-25 in ovarian cancer cells was identified to not only trigger EMT, but also block the suppressive effects of ginsenoside Rb1 on hypoxia-induced EMT by negatively targeting the E-cadherin transactivator, EP300. In conclusion, ginsenoside Rb1 may reverse hypoxia-induced EMT by abrogating the suppression of miR-25 on EP300 and E-cadherin, which suggests that ginsenoside Rb1 may be a potential therapeutic candidate for the treatment of ovarian cancer.

Deciphering Epithelial-Mesenchymal Transition Regulatory Networks in Cancer through Computational Approaches

Epithelial–mesenchymal transition (EMT), the process by which epithelial cells can convert into motile mesenchymal cells, plays an important role in development and wound healing but is also involved in cancer progression. It is increasingly recognized that EMT is a dynamic process involving multiple intermediate or “hybrid” phenotypes rather than an “all-or-none” process. However, the role of EMT in various cancer hallmarks, including metastasis, is debated. Given the complexity of EMT regulation, computational modeling has proven to be an invaluable tool for cancer research, i.e., to resolve apparent conflicts in experimental data and to guide experiments by generating testable hypotheses. In this review, we provide an overview of computational modeling efforts that have been applied to regulation of EMT in the context of cancer progression and its associated tumor characteristics. Moreover, we identify possibilities to bridge different modeling approaches and point out outstanding questions in which computational modeling can contribute to advance our understanding of pathological EMT.

Molecular or Metabolic Reprograming: What Triggers Tumor Subtypes?

Tumor heterogeneity is reflected and influenced by genetic, epigenetic, and metabolic differences in cancer cells and their interactions with a complex microenvironment. This heterogeneity has resulted in the stratification of tumors into subtypes, mainly based on cancer-specific genomic or transcriptomic profiles. Subtyping can lead to biomarker identification for personalized diagnosis and therapy, but stratification alone does not explain the origins of tumor heterogeneity. Heterogeneity has traditionally been thought to arise from distinct mutations/aberrations in "driver" oncogenes. However, certain subtypes appear to be the result of adaptation to the disrupted microenvironment caused by abnormal tumor vasculature triggering metabolic switches. Moreover, heterogeneity persists despite the predominance of single oncogenic driver mutations, perhaps due to second metabolic or genetic "hits." In certain cancer types, existing subtypes have metabolic and transcriptomic phenotypes that are reminiscent of normal differentiated cells, whereas others reflect the phenotypes of stem or mesenchymal cells. The cell-of-origin may, therefore, play a role in tumor heterogeneity. In this review, we focus on how cancer cell-specific heterogeneity is driven by different genetic or metabolic factors alone or in combination using specific cancers to illustrate these concepts. Cancer Res; 76(18); 5195-200. ©2016 AACR.

The role of hypoxia on the acquisition of epithelial-mesenchymal transition and cancer stemness: a possible link to epigenetic regulation

A hypoxic microenvironment leads to cancer progression and increases the metastatic potential of cancer cells within tumors via epithelial-mesenchymal transition (EMT) and cancer stemness acquisition. The hypoxic response pathway can occur under oxygen tensions of < 40 mmHg through hypoxia-inducible factors (HIFs), which are considered key mediators in the adaptation to hypoxia. Previous studies have shown that cellular responses to hypoxia are required for EMT and cancer stemness maintenance through HIF-1α and HIF-2α. The principal transcription factors of EMT include Twist, Snail, Slug, Sip1 (Smad interacting protein 1), and ZEB1 (zinc finger E-box-binding homeobox 1). HIFs bind to hypoxia response elements within the promoter region of these genes and also target cancer stem cell-associated genes and mediate transcriptional responses to hypoxia during stem cell differentiation. Acquisition of stemness characteristics in epithelial cells can be induced by activation of the EMT process. The mechanism of these phenotypic changes includes epigenetic alterations, such as DNA methylation, histone modification, chromatin remodeling, and microRNAs. Increased expression of EMT and pluripotent genes also play a role through demethylation of their promoters. In this review, we summarize the role of hypoxia on the acquisition of EMT and cancer stemness and the possible association with epigenetic regulation, as well as their therapeutic applications.

Unravelling the complexity of signalling networks in cancer: A review of the increasing role for computational modelling

Cancer induction is a highly complex process involving hundreds of different inducers but whose eventual outcome is the same. Clearly, it is essential to understand how signalling pathways and networks generated by these inducers interact to regulate cell behaviour and create the cancer phenotype. While enormous strides have been made in identifying key networking profiles, the amount of data generated far exceeds our ability to understand how it all "fits together". The number of potential interactions is astronomically large and requires novel approaches and extreme computation methods to dissect them out. However, such methodologies have high intrinsic mathematical and conceptual content which is difficult to follow. This review explains how computation modelling is progressively finding solutions and also revealing unexpected and unpredictable nano-scale molecular behaviours extremely relevant to how signalling and networking are coherently integrated. It is divided into linked sections illustrated by numerous figures from the literature describing different approaches and offering visual portrayals of networking and major conceptual advances in the field. First, the problem of signalling complexity and data collection is illustrated for only a small selection of known oncogenes. Next, new concepts from biophysics, molecular behaviours, kinetics, organisation at the nano level and predictive models are presented. These areas include: visual representations of networking, Energy Landscapes and energy transfer/dissemination (entropy); diffusion, percolation; molecular crowding; protein allostery; quinary structure and fractal distributions; energy management, metabolism and re-examination of the Warburg effect. The importance of unravelling complex network interactions is then illustrated for some widely-used drugs in cancer therapy whose interactions are very extensive. Finally, use of computational modelling to develop micro- and nano- functional models ("bottom-up" research) is highlighted. The review concludes that computational modelling is an essential part of cancer research and is vital to understanding network formation and molecular behaviours that are associated with it. Its role is increasingly essential because it is unravelling the huge complexity of cancer induction otherwise unattainable by any other approach.

Similarity in gene-regulatory networks suggests that cancer cells share characteristics of embryonic neural cells

Cancer cells are immature cells resulting from cellular reprogramming by gene misregulation, and redifferentiation is expected to reduce malignancy. It is unclear, however, whether cancer cells can undergo terminal differentiation. Here, we show that inhibition of the epigenetic modification enzyme enhancer of zeste homolog 2 (EZH2), histone deacetylases 1 and 3 (HDAC1 and -3), lysine demethylase 1A (LSD1), or DNA methyltransferase 1 (DNMT1), which all promote cancer development and progression, leads to postmitotic neuron-like differentiation with loss of malignant features in distinct solid cancer cell lines. The regulatory effect of these enzymes in neuronal differentiation resided in their intrinsic activity in embryonic neural precursor/progenitor cells. We further found that a major part of pan-cancer-promoting genes and the signal transducers of the pan-cancer-promoting signaling pathways, including the epithelial-to-mesenchymal transition (EMT) mesenchymal marker genes, display neural specific expression during embryonic neurulation. In contrast, many tumor suppressor genes, including the EMT epithelial marker gene that encodes cadherin 1 (CDH1), exhibited non-neural or no expression. This correlation indicated that cancer cells and embryonic neural cells share a regulatory network, mediating both tumorigenesis and neural development. This observed similarity in regulatory mechanisms suggests that cancer cells might share characteristics of embryonic neural cells.

Atypical Teratoid Rhabdoid Tumor: Two Case Reports and an Analysis of Adult Cases with Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial–mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally.

The Mitochondrial Complex(I)ty of Cancer

Recent evidence highlights that the cancer cell energy requirements vary greatly from normal cells and that cancer cells exhibit different metabolic phenotypes with variable participation of both glycolysis and oxidative phosphorylation. NADH-ubiquinone oxidoreductase (Complex I) is the largest complex of the mitochondrial electron transport chain and contributes about 40% of the proton motive force required for mitochondrial ATP synthesis. In addition, Complex I plays an essential role in biosynthesis and redox control during proliferation, resistance to cell death, and metastasis of cancer cells. Although knowledge about the structure and assembly of Complex I is increasing, information about the role of Complex I subunits in tumorigenesis is scarce and contradictory. Several small molecule inhibitors of Complex I have been described as selective anticancer agents; however, pharmacologic and genetic interventions on Complex I have also shown pro-tumorigenic actions, involving different cellular signaling. Here, we discuss the role of Complex I in tumorigenesis, focusing on the specific participation of Complex I subunits in proliferation and metastasis of cancer cells.

In Situ Microprobe Single-Cell Capillary Electrophoresis Mass Spectrometry: Metabolic Reorganization in Single Differentiating Cells in the Live Vertebrate (Xenopus laevis) Embryo

Knowledge of single-cell metabolism would provide a powerful look into cell activity changes as cells differentiate to all the tissues of the vertebrate embryo. However, single-cell mass spectrometry technologies have not yet been made compatible with complex three-dimensional changes and rapidly decreasing cell sizes during early development of the embryo. Here, we bridge this technological gap by integrating capillary microsampling, microscale metabolite extraction, and capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS) to enable direct metabolic analysis of identified cells in the live frog embryo (Xenopus laevis). Microprobe CE-ESI-MS of <0.02% of the single-cell content allowed us to detect ∼230 different molecular features (positive ion mode), including 70 known metabolites, in single dorsal and ventral cells in 8-to-32-cell embryos. Relative quantification followed by multivariate and statistical analysis of the data found that microsampling enhanced detection sensitivity compared to whole-cell dissection by minimizing chemical interferences and ion suppression effects from the culture media. In addition, higher glutathione/oxidized glutathione ratios suggested that microprobed cells exhibited significantly lower oxidative stress than those dissected from the embryo. Fast (5 s/cell) and scalable microsampling with minimal damage to cells in the 8-cell embryo enabled duplicate and triplicate metabolic analysis of the same cell, which surprisingly continued to divide to the 16-cell stage. Last, we used microprobe single-cell CE-ESI-MS to uncover previously unknown reorganization of the single-cell metabolome as the dorsal progenitor cell from the 8-cell embryo formed the neural tissue fated clone through divisions to the 32-cell embryo, peering, for the first time, into the formation of metabolic single-cell heterogeneity during early development of a vertebrate embryo.

Targeting of CCBE1 by miR-330-3p in human breast cancer promotes metastasis

Background:

MicroRNAs (miRs) are involved in the regulation of many processes that contribute to malignancy, including cell proliferation, radiation resistance, invasion and metastasis. The role of miR-330-3p, an miR upregulated in breast cancer, remains unclear.

Methods:

We examine the association of miR-330-3p with distant relapse-free survival in the Oxford cohort of breast cancer patients. We also study miR-330-3p function using in vitro invasion and ex ovo metastasis assays. Using in vitro luciferase assays, we validate a novel target gene for miR-330-3p, Collagen And Calcium Binding EGF Domains 1 (CCBE1). We assess functional consequences of CCBE1 loss by using siRNA-mediated knockdown followed by in vitro invasion assays. Lastly, we examine the expression profile of CCBE1 in breast carcinomas in the Curtis and TCGA Breast Cancer data sets using Oncomine Platform as well as distant relapse-free and overall survival of patients in the Helsinki University breast cancer data set according to CCBE1 expression status.

Results:

miR-330-3p is enriched in breast cancer, and higher levels of miR-330-3p expression are associated with lower distant relapse-free survival in a cohort of breast cancer patients. Consistent with these observations, overexpression of miR-330-3p in breast cancer cell lines results in greater invasiveness in vitro, and miR-330-3p-overexpressing cells also metastasise more aggressively ex ovo. We identify CCBE1 as a direct target of miR-330-3p, and show that knockdown of CCBE1 results in a greater invasive capacity. Accordingly, in breast cancer patients CCBE1 is frequently downregulated, and its loss is associated with reduced distant relapse-free and overall survival.

Conclusions:

We show for the first time that miR-330-3p targets CCBE1 to promote invasion and metastasis. miR-330-3p and CCBE1 may represent promising biomarkers in breast cancer.

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells

Phenotypic plasticity refers to a phenomenon in which cells transiently gain traits of another lineage. During carcinoma progression, phenotypic plasticity drives invasion, dissemination and metastasis. Indeed, while most of the studies of phenotypic plasticity have been in the context of epithelial-derived carcinomas, it turns out sarcomas, which are mesenchymal in origin, also exhibit phenotypic plasticity, with a subset of sarcomas undergoing a phenomenon that resembles a mesenchymal-epithelial transition (MET). Here, we developed a method comprising the miR-200 family and grainyhead-like 2 (GRHL2) to mimic this MET-like phenomenon observed in sarcoma patient samples.We sequentially express GRHL2 and the miR-200 family using cell transduction and transfection, respectively, to better understand the molecular underpinnings of these phenotypic transitions in sarcoma cells. Sarcoma cells expressing miR-200s and GRHL2 demonstrated enhanced epithelial characteristics in cell morphology and alteration of epithelial and mesenchymal biomarkers. Future studies using these methods can be used to better understand the phenotypic consequences of MET-like processes on sarcoma cells, such as migration, invasion, metastatic propensity, and therapy resistance.

Expression and significance of GRHL2 in esophageal cancer

Esophageal cancer (EC) is one of the most common causes of cancer-related mortality in the world. Although much effort has been made to improve the 5-year survival rate of patients with EC, it still remains low due to diagnosis at an advanced stage, aggressive local invasion, early metastasis, and resistance to chemotherapy. Although grainyhead-like 2 (GRHL2) has attracted interest since it has been recently identified as a novel suppressor of the epithelial–mesenchymal transition, clinical values of GRHL2 and its relationship with the metastasis-related factors, such as hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF), remain unclear. In order to investigate the expression of GRHL2, HIF-1α, and VEGF, and their correlation with angiogenesis in EC, 63 patients with EC were examined. The expression of GRHL2, HIF-1α, and VEGF in tumor tissues was higher than that in adjacent tissues and was associated with tumor differentiation. GRHL2 expression was significantly correlated with lymph node metastasis and invasion depth, whereas VEGF expression was associated with tumor (TNM) stage. A significant correlation was found between the expression of GRHL2 and HIF-1α. The patients expressing low GRHL2 and high HIF-1α showed significant reduction in both overall survival rate and disease-free survival rate. The results demonstrated that abnormal expression of GRHL2 is common in EC, and low expression of GRHL2 accompanied by a high expression of HIF-1α indicates poor prognosis.

Curcumin reverses benzidine-induced epithelial-mesenchymal transition via suppression of ERK5/AP-1 in SV-40 immortalized human urothelial cells

Overexposure to benzidine has been manifested as an important cause of bladder cancer. However, the molecular mechanism of benzidine-induced malignancy is still insufficiently interpreted. Epithelial-mesenchymal transition (EMT) is a crucial pathophysiological process in embryonic development as well as initiation and development of epithelium-originated malignant tumors. The role of extracellular regulated protein kinase 5 (ERK5) in benzidine-meditated bladder cancer development has not been explored. In the present study, we explored the role of ERK5/AP-1 pathway in benzidine-induced EMT in human normal urothelial cells and the intervention effect of curcumin on bezidine-induced EMT. We found that benzidine-induced EMT in SV-40 immortalized human urothelial cells (SV-HUC-1) at low concentrations. We detected that ERK5/AP-1 pathway was notably activated. Specific ERK5 inhibitor, XMD8-92 was applied to determine the role of ERK5 in benzidine-induced EMT. Results indicated that XMD8-92 reversed the EMT process. Furthermore, curcumin effectively attenuated benzidine-induced urocystic EMT by suppressing ERK5/AP-1 pathway. In conclusion, the present study revealed the positive role of ERK5/AP-1 in benzidine-provoked urocystic EMT and the curcumin promising use in bladder cancer prevention and intervention via ERK5/AP-1 pathway.

Macrophage migration inhibitory factor: a potential driver and biomarker for head and neck squamous cell carcinoma

Macrophage migration inhibitory factor (MIF), a pleiotropic proinflammatory cytokine, has been showed to be associated with the immunopathogenesis of many diseases. Recent study demonstrated that MIF promoted tumorigenesis and tumor progression and played a critical role in various kinds of human cancer including head and neck squamous cell carcinoma(HNSCC). Hence, in this paper we retrospected the relationship between MIF and angiogenesis, epithelial-mesenchymal transition (EMT), inflammation, immune response, hypoxia microenvironment, and discussed whether it is a promising biomarker for diagnosis and supervisor of HNSCC.

Osthole inhibited TGF β-induced epithelial-mesenchymal transition (EMT) by suppressing NF-κB mediated Snail activation in lung cancer A549 cells

Epithelial-mesenchymal transition (EMT), the transdifferentiation of epithelial cells into mesenchymal cells, has been implicated in the metastasis and provides novel strategies for cancer therapy. Osthole (OST), a dominant active constituent of Chinese herb Cnidium monnieri, has been reported to inhibit cancer metastasis while the mechanisms remains unclear. Here, we studied the inhibitory effect and mechanisms of OST on TGF-β1-induced EMT in A549 cells. Cells were treated with TGF-β1 in the absence and presence of OST. The morphological alterations were observed with a microscopy. The protein and mRNA expressions were determined by Western blotting and real-time PCR. The protein localization was detected with immunofluorescence. The adhesion, migration, and invasion were determined by Matrigel, wound-healing, and Transwell assays. TGF-β1 treatment induced spindle-shaped alterations of cells, upregulation of N-cadherin, Vimentin, NF-κB p65, and downregulation of E-cadherin. Dysregulated membrane expression and mRNA expression of E-cadherin and N-cadherin were observed after TGF-β1 treatment. TGF-β1 increased abilities of migration and invasion and triggered the nuclear translocation of NF-κB p65. These alterations were dramatically inhibited by OST. Furthermore, PDTC, a NF-κB inhibitor, showed similar effects. In addition, TGF-β1-induced expression of Snail was significantly inhibited by OST and silenced Snail partially reversed TGF-β1-induced EMT biomarkers without affecting NF-κB p-65. In conclusion, OST inhibited TGF-β1-induced EMT, adhesion, migration, and invasion through inactivation of NF-κB-Snail pathways in A549 cells. This study provides novel molecular mechanisms for the anti-metastatic effect of OST.

Accumulation of low-dose BIX01294 promotes metastatic potential of U251 glioblastoma cells

BIX01294 (Bix) is known to be a euchromatic histone-lysine N-methyltransferase 2 inhibitor and treatment with Bix suppresses cancer cell survival and proliferation. In the present study, it was observed that sequential treatment with low-dose Bix notably increases glioblastoma cell migration and metastasis. It was demonstrated that U251 cells sequentially treated with low-dose Bix exhibited induced characteristic changes in critical epithelial-mesenchymal transition (EMT) markers, including E-cadherin, N-cadherin, β-catenin and zinc finger protein SNAI2. Notably, sequential treatment with Bix also increased the expression of cancer stem cell-associated markers, including sex determining region Y-box 2, octamer-binding transcription factor 4 and cluster of differentiation 133. Neurosphere formation was significantly enhanced in cells sequentially treated with Bix, compared with control cells (control: P=0.011; single treatment of Bix, P=0.045). The results of the present study suggest that accumulation of low-dose Bix enhanced the migration and metastatic potential of glioblastoma cells by regulating EMT-associated gene expression, which may be the cause of the altered properties of glioblastoma stem cells.

Effect of Slug-Mediated Down-Regulation of E-Cadherin on Invasiveness and Metastasis of Anaplastic Thyroid Cancer Cells

BACKGROUND Slug has been found to promote migration and invasion of many cancer cells, including anaplastic thyroid cancer (ATC). Thus, targeting Slug expression could provide new approaches for the treatment of patients with ATC. MATERIAL AND METHODS Small interfering RNA (siRNA) targeting Slug (Slug siRNA) was used to construct clonal derivatives in the metastatic ATC SW1736 cells. Slug cDNA transfection was used to restore the Slug expression in the Slug siRNA-transfected SW1736 cells (Slug siRNA/SW1736). E-cadherin siRNA was used to inhibit E-cadherin expression in the Slug siRNA/SW1736 cells. The SW1736 cell migration, invasion, and signaling pathway was analyzed in vitro. Furthermore, the stable Slug siRNA-transfected SW1736 clones were used for the lung metastasis assay in an in vivo mouse model. RESULTS Targeting Slug expression in SW1736 cells showed a 45% decrease in migration and an 85% decrease in invasiveness in vitro. Knockdown of E-cadherin by E-cadherin siRNA transfection or Slug overexpression by Slug cDNA transfection restored the invasive and migrative ability in SW1736 cells. In addition, we found an 80% decrease in the number of macroscopic lung metastases nodes of mice by in vivo analysis. Western blot assay showed that Slug expression was inhibited and E-cadherin expression was increased in the Slug siRNA-transfected tumors. CONCLUSIONS Targeting Slug signaling pathway is effective in preventing lung metastasis in ATC.

ΔNp63α and microRNAs: leveraging the epithelial-mesenchymal transition

The epithelial-mesenchymal transition (EMT) is a cellular reprogramming mechanism that is an underlying cause of cancer metastasis. Recent investigations have uncovered an intricate network of regulation involving the TGFβ, Wnt, and Notch signaling pathways and small regulatory RNA species called microRNAs (miRNAs). The activity of a transcription factor vital to the maintenance of epithelial stemness, ΔNp63α, has been shown to modulate the activity of these EMT pathways to either repress or promote EMT. Furthermore, ΔNp63α is a known regulator of miRNA, including those directly involved in EMT. This review discusses the evidence of ΔNp63α as a master regulator of EMT components and miRNA, highlighting the need for a deeper understanding of its role in EMT. This expanded knowledge may provide a basis for new developments in the diagnosis and treatment of metastatic cancer.

KLF6 inhibited oral cancer migration and invasion via downregulation of mesenchymal markers and inhibition of MMP-9 activities

Krüppel-like factors can bind to specific DNA motifs and regulate various cellular functions, such as metabolism, cell proliferation, and differentiation. Krüppel-like factor 6 (KLF6), a member of this family, is downregulated in human cancers. Oral cancer is a highly prevalent type in Taiwan. Although KLF6 overexpression in human cancer cells inhibits cell proliferation, induces apoptosis, and attenuates cell migration, the effects of KLF6 on oral cancer remains poorly elucidated. This study investigated the role of KLF6 in oral cancer tumorigenesis. Immunohistochemical staining revealed that nuclear KLF6 level was significantly and inversely associated with tumor size and stages. KLF6 overexpression attenuated the migration and invasion of oral cancer SAS cells. Zymography assay demonstrated that KLF6 inhibited the activities of matrix metalloproteinase 9 (MMP-9) and weakened the expression of mesenchymal markers, such as snail, slug, and vimentin. Our study is the first to provide demonstrate that KLF6 functions as a tumor suppressor gene and prevents the metastasis of oral cancer cells.

AECHL-1 targets breast cancer progression via inhibition of metastasis, prevention of EMT and suppression of Cancer Stem Cell characteristics

Triple negative breast cancer (TNBC) features among the most aggressive manifestations of cancer due to its enhanced metastatic potential and immunity to therapeutics which target hormone receptors. Under such scenarios, anti-cancer compounds with an ability to influence multiple targets, or an entire process, will have an advantage over specific signal transduction inhibitors. To counter the metastatic threat it is essential to target cellular components central to the processes of cancer cell migration and adaptation. Our previous work on a novel triterpenoid, AECHL-1, explored its anti-cancer potential, and linked it to elevated ER stress in cancer cells, while its anti-angiogenic potential was credited for its ability to manipulate the cytoskeleton. Here, we broaden its range of action by showing that it curbs the metastatic ability of TNBC cells, both in vitro in MDA-MB-231 cell line and in vivo, in mouse models of metastasis. AECHL-1 does so by disrupting the cytoskeletal network, and also suppressing NF-κB and β-Catenin mediated key molecular pathways. These activities also contributed to AECHL-1 mediated suppression of TGF-β/TNF-α induced Epithelial to Mesenchymal Transition (EMT) and cancer stem cell characteristic. Thus, we present AECHL-1 as a promising therapeutic inhibitor of metastatic disease.

Lipocalin2 suppresses metastasis of colorectal cancer by attenuating NF-κB-dependent activation of snail and epithelial mesenchymal transition

Background

Lipocalin2 (LCN2) is a secretory protein that is aberrantly expressed in several types of cancer and has been involved in metastatic progression. However, neither mechanisms nor the role that LCN2 plays in the metastasis of colorectal cancer are clear.

Methods

LCN2 expression in colorectal cancer was detected by immunohistochemistry in 400 tissue specimens and Kaplan-Meier survival analysis was performed. In vitro, real-time PCR, western blot, colony formation assay, immunofluorescence assay, wound healing assay, migration and invasion experiment were performed to investigate the effects of LCN2 in epithelial mesenchymal transition (EMT), migration and invasion, respectively. In vivo mouse xenograft and metastasis models were utilized to determine tumorigenicity and metastasis ability, and immunohistochemistry, real-time PCR, western blot were used to evaluate the related protein expression. Luciferase reporter assay was used to explore the role of LCN2 on NF-ĸB promoter.

Results

LCN2 was highly expressed in 66.5% of the specimens, and significantly correlated with positive E-cadherin in the membrane and negative nuclear β-catenin. Higher expression of LCN2 together with negative NF-κB expression was negatively related to nuclear accumulation of snail and predicted favorable prognosis. LCN2 blocked cell proliferation, migration and invasion in vitro and in vivo, and inhibited translocation of NF-κB into nucleus. NF-κB could reverse the effect of LCN2 on EMT and promote snail expression. Rescued snail expression had similar effect without influencing NF-κB activity.

Conclusion

LCN2 may be an important negative regulator in EMT, invasion and metastasis of CRC via acting as upstream of NF-κB/snail signaling pathway. Thereby combinative manipulation of LCN2 and NF-κB/snail pathway may represent a novel and promising therapeutic approach for the patients with CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0564-9) contains supplementary material, which is available to authorized users.

Runx2 expression: A mesenchymal stem marker for cancer

The transcription factor runt-related transcription factor 2 (Runx2) is a master gene implicated in the osteogenic differentiation of mesenchymal stem cells, and thus serves a determinant function in bone remodelling and skeletal integrity. Various signalling pathways regulate Runx2 abundance, which requires a number of molecules to finely modulate its expression. Furthermore, this gene may be ectopically-expressed in cancer cells. Recent studies have reported the involvement of Runx2 in cell proliferation, epithelial-mesenchymal transition, apoptosis and metastatic processes, suggesting it may represent a useful therapeutic target in cancer treatment. However, studies evaluating this gene as a cancer marker are lacking. In the present study, Runx2 expression was analysed in 11 different cancer cell lines not derived from bone tumour. In addition, the presence of Runx2-related cell-free RNA was examined in the peripheral blood of 41 patients affected by different forms of tumours. The results demonstrated high expression levels of Runx2 in the cancer cell lines and identified the presence of Runx2-related cell-free RNA in the peripheral blood of patients with cancer. As compared with normal individuals, the expression level was increased by 14.2-fold in patients with bone metastases and by 4.01-fold in patients without metastases. The results of the present study therefore opens up the possibility to exploit Runx2 expression as a cancer biomarker allowing the use of minimally invasive approaches for diagnosis and follow-up.

Mesenchymal-Epithelial Transition in Sarcomas Is Controlled by the Combinatorial Expression of MicroRNA 200s and GRHL2

Phenotypic plasticity involves a process in which cells transiently acquire phenotypic traits of another lineage. Two commonly studied types of phenotypic plasticity are epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). In carcinomas, EMT drives invasion and metastatic dissemination, while MET is proposed to play a role in metastatic colonization. Phenotypic plasticity in sarcomas is not well studied; however, there is evidence that a subset of sarcomas undergo an MET-like phenomenon. While the exact mechanisms by which these transitions occur remain largely unknown, it is likely that some of the same master regulators that drive EMT and MET in carcinomas also act in sarcomas. In this study, we combined mathematical models with bench experiments to identify a core regulatory circuit that controls MET in sarcomas. This circuit comprises the microRNA 200 (miR-200) family, ZEB1, and GRHL2. Interestingly, combined expression of miR-200s and GRHL2 further upregulates epithelial genes to induce MET. This effect is phenocopied by downregulation of either ZEB1 or the ZEB1 cofactor, BRG1. In addition, an MET gene expression signature is prognostic for improved overall survival in sarcoma patients. Together, our results suggest that a miR-200, ZEB1, GRHL2 gene regulatory network may drive sarcoma cells to a more epithelial-like state and that this likely has prognostic relevance.

Epithelial-mesenchymal transition-associated microRNA/mRNA signature is linked to metastasis and prognosis in clear-cell renal cell carcinoma

Clear-cell renal cell carcinomas (ccRCCs) are genetically heterogeneous tumors presenting diverse clinical courses. Epithelial-mesenchymal transition (EMT) is a crucial process involved in initiation of metastatic cascade. The aim of our study was to identify an integrated miRNA/mRNA signature associated with metastasis and prognosis in ccRCC through targeted approach based on analysis of miRNAs/mRNAs associated with EMT. A cohort of 230 ccRCC was included in our study and further divided into discovery, training and validation cohorts. EMT markers were evaluated in ccRCC tumor samples, which were grouped accordingly to EMT status. By use of large-scale miRNA/mRNA expression profiling, we identified miRNA/mRNA with significantly different expression in EMT-positive tumors and selected 41 miRNAs/mRNAs for training phase of the study to evaluate their diagnostic and prognostic potential. Fifteen miRNAs/mRNAs were analyzed in the validation phase, where all evaluated miRNA/mRNA candidates were confirmed to be significantly deregulated in tumor tissue. Some of them significantly differed in metastatic tumors, correlated with clinical stage, with Fuhrman grade and with overall survival. Further, we established an EMT-based stage-independent prognostic scoring system enabling identification of ccRCC patients at high-risk of cancer-related death. Finally, we confirmed involvement of miR-429 in EMT regulation in RCC cells in vitro.

The environmental carcinogen benzo[a]pyrene induces a Warburg-like metabolic reprogramming dependent on NHE1 and associated with cell survival

Cancer cells display alterations in many cellular processes. One core hallmark of cancer is the Warburg effect which is a glycolytic reprogramming that allows cells to survive and proliferate. Although the contributions of environmental contaminants to cancer development are widely accepted, the underlying mechanisms have to be clarified. Benzo[a]pyrene (B[a]P), the prototype of polycyclic aromatic hydrocarbons, exhibits genotoxic and carcinogenic effects, and it is a human carcinogen according to the International Agency for Research on Cancer. In addition to triggering apoptotic signals, B[a]P may induce survival signals, both of which are likely to be involved in cancer promotion. We previously suggested that B[a]P-induced mitochondrial dysfunctions, especially membrane hyperpolarization, might trigger cell survival signaling in rat hepatic epithelial F258 cells. Here, we further characterized these dysfunctions by focusing on energy metabolism. We found that B[a]P promoted a metabolic reprogramming. Cell respiration decreased and lactate production increased. These changes were associated with alterations in the tricarboxylic acid cycle which likely involve a dysfunction of the mitochondrial complex II. The glycolytic shift relied on activation of the Na⁺/H⁺ exchanger 1 (NHE1) and appeared to be a key feature in B[a]P-induced cell survival related to changes in cell phenotype (epithelial-to-mesenchymal transition and cell migration).

MicroRNA profiles in various hepatocellular carcinoma cell lines

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-associated mortality worldwide. Although surgery is considered the most effective treatment for patients with HCC, its indication is restricted by limited criteria and a high relapse rate following surgery; therefore, systemic chemotherapy is required for patients with advanced-stage HCC to prolong their survival. MicroRNAs (miRNAs) are endogenous non-coding RNAs of 18-22 nucleotides in length. It has been reported that aberrant expression of miRNAs is a feature shared by various types of human cancer. Previous studies have indicated that the modulation of non-coding RNAs, particularly miRNAs, may be a valuable therapeutic target for HCC. The aim of the present study was to elucidate the miRNA profiles associated with differentiation and hepatitis B virus (HBV) infection observed in HCC cell lines. The human Alex, Hep3B, HepG2, HuH1, HuH7, JHH1, JHH2, JHH5, JHH6, HLE, HLF and Li-7 HCC cell lines were used for an miRNA array. Replicate data were analyzed following their classification into: i) Poorly- and well-differentiated human HCC cells and ii) HBV-positive and -negative human HCC cells. Out of the 1,719 miRNAs, 4 were found to be significantly upregulated and 52 significantly downregulated in the poorly-differentiated cells, as compared with the well-differentiated cells. Conversely, in the HBV-positive cells 125 miRNAs were found to be upregulated and 2 downregulated, as compared with the HBV-negative cells. Unsupervised hierarchical clustering analysis with Pearson's correlation revealed that the miRNA expression levels were clustered both together and separately in each group. In conclusion, miRNA profile characterization based on various parameters may be a novel approach to determine the etiology of HCC.

EGFR Signal-Network Reconstruction Demonstrates Metabolic Crosstalk in EMT

Epithelial to mesenchymal transition (EMT) is an important event during development and cancer metastasis. There is limited understanding of the metabolic alterations that give rise to and take place during EMT. Dysregulation of signalling pathways that impact metabolism, including epidermal growth factor receptor (EGFR), are however a hallmark of EMT and metastasis. In this study, we report the investigation into EGFR signalling and metabolic crosstalk of EMT through constraint-based modelling and analysis of the breast epithelial EMT cell model D492 and its mesenchymal counterpart D492M. We built an EGFR signalling network for EMT based on stoichiometric coefficients and constrained the network with gene expression data to build epithelial (EGFR_E) and mesenchymal (EGFR_M) networks. Metabolic alterations arising from differential expression of EGFR genes was derived from a literature review of AKT regulated metabolic genes. Signaling flux differences between EGFR_E and EGFR_M models subsequently allowed metabolism in D492 and D492M cells to be assessed. Higher flux within AKT pathway in the D492 cells compared to D492M suggested higher glycolytic activity in D492 that we confirmed experimentally through measurements of glucose uptake and lactate secretion rates. The signaling genes from the AKT, RAS/MAPK and CaM pathways were predicted to revert D492M to D492 phenotype. Follow-up analysis of EGFR signaling metabolic crosstalk in three additional breast epithelial cell lines highlighted variability in in vitro cell models of EMT. This study shows that the metabolic phenotype may be predicted by in silico analyses of gene expression data of EGFR signaling genes, but this phenomenon is cell-specific and does not follow a simple trend.

Grainyhead-like 2 inhibits the coactivator p300, suppressing tubulogenesis and the epithelial-mesenchymal transition

GRHL2 suppresses EMT to give a default epithelial phenotype. GRHL2 inhibits this process through the histone acetyltransferase coactivator p300, repressing the partial EMT and preventing induction of MMPs. The results demonstrate novel roles for p300 and GRHL2 in promoting or suppressing EMT in morphogenesis and tumor progression.

Developmental morphogenesis and tumor progression require a transient or stable breakdown of epithelial junctional complexes to permit programmed migration, invasion, and anoikis resistance, characteristics endowed by the epithelial–mesenchymal transition (EMT). The epithelial master-regulatory transcription factor Grainyhead-like 2 (GRHL2) suppresses and reverses EMT, causing a mesenchymal–epithelial transition to the default epithelial phenotype. Here we investigated the role of GRHL2 in tubulogenesis of Madin–Darby canine kidney cells, a process requiring transient, partial EMT. GRHL2 was required for cystogenesis, but it suppressed tubulogenesis in response to hepatocyte growth factor. Surprisingly, GRHL2 suppressed this process by inhibiting the histone acetyltransferase coactivator p300, preventing the induction of matrix metalloproteases and other p300-dependent genes required for tubulogenesis. A 13–amino acid region of GRHL2 was necessary for inhibition of p300, suppression of tubulogenesis, and interference with EMT. The results demonstrate that p300 is required for partial or complete EMT occurring in tubulogenesis or tumor progression and that GRHL2 suppresses EMT in both contexts through inhibition of p300.

Is age-related failure of metabolic reprogramming a principal mediator in idiopathic Parkinson's disease? Implications for treatment and inverse cancer risk

Idiopathic Parkinson's disease (IPD) is a neurodegenerative disorder characterized by selective degeneration of the substantia nigra pars compacta (SNc), dorsal motor nucleus of the vagus and other vulnerable nervous system regions characterized by extensive axonal arborization and intense energy requirements. Systemic age-related depression of mitochondrial function, oxidative phosphorylation (OXPHOS) and depressed expression of genes supporting energy homeostasis is more severe in IPD than normal aging such that energy supply may exceed regional demand. In IPD, the overall risk of malignancy is reduced. Cancer is a collection of proliferative diseases marked by malignant transformation, dysregulated mitosis, invasion and metastasis. Many cancers demonstrate normal mitochondrial function, preserved OXPHOS, competent mechanisms of energy homeostasis, and metabolic reprogramming capacities that are lacking in IPD. Metabolic reprogramming adjusts OXPHOS and glycolytic pathways in response to changing metabolic needs. These opposite metabolic features form the basis of a two component hypothesis. First, that depressed mitochondrial function, OXPHOS deficiency and impaired metabolic reprogramming contribute to focal energy failure, neurodegeneration and disease expression in IPD. Second, that the same systemic metabolic deficits inhibit development and proliferation of malignancies in IPD. Studies of mitochondrial aging, familial PD (FPD), the lysosomal storage disorder, Gaucher's disease, Parkinson's disease cybrids, the mitochondrial cytopathies, and disease-related metabolic reprogramming both in IPD and cancer provide support for this model.