Lisha Qi

Chemokine CXCL12 and its receptor CXCR4 expression are associated with perineural invasion of prostate cancer

ObjectiveTo identify the roles of CXCL12 and CXCR4 and the associated mechanism involved in perineural invasion of prostate cancer.MethodsThe distribution and expression of CXCL12, CXCR4, MMP-2 and MMP-9 in human prostate cancer and in tumor cells invading nerve tissue were studied with immunohistochemical staining. The effects of exogenous CXCL12 and CXCR4 antagonist AMD3100 on PC3 prostate cancer cells invasiveness were assessed in vitro and in vivo.ResultsThe expression of CXCL12, CXCR4, MMP-2, and MMP-9 in human prostate cancer were higher than those in hyperplastic prostate tissues (P < 0.05). In vitro CXCL12 could stimulate the PC3 cells invasiveness (P < 0.05) while AMD3100 could inhibit invasiveness. In vivo, the number of nerves around the tumor tissue in the group treated with CXCL12 was significantly higher than that found in the control group (P < 0.05). Both the control group and the CXCL12-treated group had more nerves number near the tumor tissue than it found in the AMD3100-treated group. The positive cell number of CXCL12, CXCR4, MMP-2, MMP-9, and NGF expression ranked from highest to lowest, were the CXCL12-treated, the control, and the AMD3100-treated group(P < 0.05).ConclusionCXCL12 and its receptor CXCR4 along with MMP-2 and MMP-9 are related with prostate cancer perineural invasion.

Dickkopf‐1 inhibits epithelial‐mesenchymal transition of colon cancer cells and contributes to colon cancer suppression

This study aimed to determine the expression pattern of dickkopf‐1 (Dkk1), a potent inhibitor of Wnt signaling, in colon cancer and to assess the function and mechanism of Dkk1 in tumor progression in vitro and in vivo. We detected the protein expression of Dkk1 and some epithelial‐mesenchymal transition (EMT)‐associated markers (E‐cadherin, vimentin and β‐catenin) in 217 tissue samples of human colon cancer, upregulated Dkk1 expression in HCT116 colon cancer cells, and established a nude mouse xenograft model. Dkk1 protein overexpression was inversely related to tumor grade and the presence of metastasis and recurrence of colon cancer. Notably, the expression of Dkk1 was concomitant with reduced immunohistochemical features of EMT (e.g. increased expression of epithelial marker E‐cadherin, decreased expression of mesenchymal marker vimentin, and cytoplasmic distribution of β‐catenin). Furthermore, Dkk1 overexpression resulted in restoration of the epithelial phenotype, decreased expression of EMT transcription factors Snail and Twist, and decreased expression of markers suggestive of intestinal stem cells (e.g. cluster of differentiation 133 [CD133] and leucine‐rich‐repeat‐containing G‐protein‐coupled receptor 5 [Lgr5]). Functional analysis showed overexpression of Dkk1 reduced proliferation, migration, and invasion of colon cancer cells. Moreover, upregulation of Dkk1 led to decreased tumor‐initiating ability and suppressed colon tumor growth in nude mice. Our findings indicate that Dkk1 can suppress the progression of colon cancer, possibly through EMT inhibition, and could therefore serve as a target for tumor therapy. (Cancer Sci 2012; 103: 828–835)

Zinc finger E-box binding homeobox 1 promotes vasculogenic mimicry in colorectal cancer through induction of epithelial-to-mesenchymal transition

Our previous studies have shown that epithelial–mesenchymal transition (EMT) may be involved in the vasculogenic mimicry (VM) formation in hepatocellular carcinoma. Here, we hypothesize that zinc finger E‐box binding homeobox 1 (ZEB1) promotes VM formation in colorectal carcinoma (CRC) by inducing EMT. We identified VM in 39 (19.2%) out of 203 CRC patients. The presence of VM was associated with aggressive biological behavior and was an unfavorable prognostic indicator. By immunohistochemical analysis, we found that the VM‐positive CRC samples showed increased ZEB1 expression compared with the VM‐negative samples and the ZEB1 expression occurred concomitantly with features of EMT. In vitro, knockdown of ZEB1 in poorly differentiated HCT116 CRC cells destroyed the vessel‐like structures in the 3‐D culture, a property associated with VM formation. Knockdown of ZEB1 resulted in restoration of epithelial phenotypes and significantly inhibited the ability to migrate and invade. In addition, ZEB1 underexpression decreased the expression of vascular endothelial (VE)‐cadherin and Flk‐1, which are characteristics of endothelial cells. Taken together, our results suggest that ZEB1 can promote VM formation by inducing EMT in CRC and might represent an important target in CRC. (Cancer Sci 2012; 103: 813–820)

Transforming growth factor-β1 induces EMT by the transactivation of epidermal growth factor signaling through HA/CD44 in lung and breast cancer cells.

Epithelial-mesenchymal transition (EMT), a process closely related to tumor development, is regulated by a variety of signaling pathways and growth factors, such as transforming growth factor-β1 (TGF-β1) and epidermal growth factor (EGF). Hyaluronan (HA) has been shown to induce EMT through either TGF-β1 or EGF signaling and to be a regulator of the crosstalk between these two pathways in fibroblasts. In this study, in order to clarify whether HA has the same effect in tumor cells, we utilized the lung cancer cell line, A549, and the breast cancer cell line, MCF-7, and found that the effects of stimulation with TGF-β1 were more potent than those of EGF in regulating the expression of EMT-associated proteins and in enhancing cell migration and invasion. In addition, we observed that TGF-β1 activated EGF receptor (EGFR) and its downstream AKT and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we found that TGF-β1 upregulated the expression of hyaluronan synthases (HAS1, HAS2 and HAS3) and promoted the expression of CD44, a cell surface receptor for HA, which interacts with EGFR, resulting in the activation of the downstream AKT and ERK pathways. Conversely, treatment with 4-methylumbelliferone (4-MU; an inhibitor of HAS) prior to stimulation with TGF-β1, inhibited the expression of CD44 and EGFR, abolished the interaction between CD44 and EGFR. Furthermore, the use of shRNA targeting CD44 impaired the expression of EGFR, deactivated the AKT and ERK pathways, reversed EMT and decreased the migration and invasion ability of cells. In conclusion, our data demonstrate that TGF-β1 induces EMT by the transactivation of EGF signaling through HA/CD44 in lung and breast cancer cells.

Wnt5a Suppresses Colon Cancer by Inhibiting Cell Proliferation and Epithelial–Mesenchymal Transition

Colon cancer remains one of the lethal malignancies in the world. Aberrant activation of canonical Wnt/β‐catenin signaling pathway has been observed in colon cancer. In contrast, the non‐canonical Wnt signaling functions remain obscure. Wnt5a is a representative non‐canonical Wnt ligand which has gained extensive attention nowadays. Wnt5a has been shown to play an important role in EMT in prostate cancer and melanoma, but its role in colon cancer is still ambiguous. Here we have evaluated Wnt5a expression in a large cohort of 217 colon cancers by immunohistochemistry and analyzed its correlation with clinicopathologic characteristics. We found that expression of Wnt5a was diminished significantly in majority of primary colon cancers and negatively related with EMT biomarkers. To further enlighten the mechanism which Wnt5a regulates EMT in vitro, we established ectopic Wnt5a expression models. Protein analysis demonstrated that Wnt5a inhibited EMT and antagonized canonical Wnt signaling in colon cancer cells. Overexpression of Wnt5a impaired cell motility and invasion and inhibited cell proliferation by manipulating Bax. Moreover, Wnt5a suppressed the tumor growth in nude mice and impaired tumorigenicity in vivo. Wnt5a also induced intracellular calcium and activated non‐canonical Wnt/Ca2+ signaling in colon cancer. In summary, although Wnt5a was down‐regulated in majority of colon cancers, enhanced Wnt5a expression predict preferable outcome in colon cancer patients. Our findings indicate that Wnt5a might act as tumor suppressor by inhibiting cell proliferation and attenuating EMT in colon cancer cells. Wnt5a could be used as a novel prognostic marker and/or therapeutic target for colon cancer in the future. J. Cell. Physiol. 229: 1908–1917, 2014.

Wnt3a Promotes the Vasculogenic Mimicry Formation of Colon Cancer via Wnt/β-Catenin Signaling.

Our previous study provided evidence that non-canonical Wnt signaling is involved in regulating vasculogenic mimicry (VM) formation. However, the functions of canonical Wnt signaling in VM formation have not yet been explored. In this study, we found the presence of VM was related to colon cancer histological differentiation (p < 0.001), the clinical stage (p < 0.001), and presence of metastasis and recurrence (p < 0.001). VM-positive colon cancer samples showed increased Wnt3a expression (p < 0.001) and β-catenin nuclear expression (p < 0.001) compared with the VM-negative samples. In vitro, over-regulated Wnt3a expression in HT29 colon cancer cells promoted the capacity to form tube-like structures in the three-dimensional (3-D) culture together with increased expression of endothelial phenotype-associated proteins such as VEGFR2 and VE-cadherin. The mouse xenograft model showed that Wnt3a-overexpressing cells grew into larger tumor masses and formed more VM than the control cells. In addition, the Wnt/β-catenin signaling antagonist Dickkopf-1(Dkk1) can reverse the capacity to form tube-like structures and can decrease the expressions of VEGFR2 and VE-cadherin in Wnt3a-overexpressing cells. Taken together, our results suggest that Wnt/β-catenin signaling is involved in VM formation in colon cancer and might contribute to the development of more accurate treatment modalities aimed at VM.

Dickkopf‐1 expression is down‐regulated during the colorectal adenoma–carcinoma sequence and correlates with reduced microvessel density and VEGF expression

Dickkopf‐1 (Dkk1), an antagonist of the Wnt–β‐catenin signalling pathway, has been reported to play a role in cancer progression. However, little is known about the role of Dkk1 during the colorectal adenoma–carcinoma sequence. This study aimed to elucidate the role of Dkk1 in tumorigenesis and angiogenesis in colorectal cancer.

FGF4 induces epithelial-mesenchymal transition by inducing store-operated calcium entry in lung adenocarcinoma

Several fibroblast growth factor (FGF) isoforms act to stimulate epithelial-mesenchymal transition (EMT) during cancer progression. FGF4 and FGF7 are two ligands of FGF receptor 2 (FGFR2). Using two lung adenocarcinoma (ADC) cell lines, A549 and H1299, we showed that FGF4, but not FGF7, altered cell morphology, promoted EMT-associated protein expression, and enhanced cell proliferation, migration/invasion and colony initiation. In addition, FGF4 increased store-operated calcium entry (SOCE) and expression of the calcium signal-associated protein Orai1. The SOCE inhibitor 2,5-di-tert-butylhydroquinone (BHQ) or Orai1 knockdown reversed all of the EMT-promoting effects of FGF4. BHQ also inhibited FGF4-induced EMT in a mouse xenograft model. Finally, 60 human lung ADC samples and 21 sets of matched specimens (primary and metastatic foci in lymph nodes from one patient) were used to confirm the clinicopathologic significance of FGF4 and its correlation with E-cadherin, Vimentin and Orai1 expression. Our study thus shows that FGF4 induces EMT by elevating SOCE in lung ADC.

Human nonsense-mediated RNA decay regulates EMT by targeting the TGF-ß signaling pathway in lung adenocarcinoma

Nonsense-mediated mRNA decay (NMD) is a highly conserved pathway that selectively degrades aberrant RNA transcripts. In this study, we proved that NMD regulates the epithelial-mesenchymal transition (EMT) of lung adenocarcinoma (ADC). Moreover, we found that NMD core factor UP-frameshift 1 tends to be expressed at lower levels in human ADC tissues than in normal lung tissues, thereby raising the possibility that NMD may be downregulated to permit ADC oncogenesis. Our experiments in human ADC cell lines showed that downregulating NMD can promote EMT. Moreover, EMT can be inhibited by upregulating NMD. We tested the role of TGF-ß signaling and found that NMD influences EMT by targeting the TGF-ß signaling pathway. Our findings reveal that NMD is a potential tumor regulatory mechanism and may be a potential therapeutic target for ADC.

VEGFR2 regulates endothelial differentiation of colon cancer cells

BackgroundRecent studies suggested that cancer stem-like cells contribute to tumor vasculogenesis by differentiating into endothelial cells. However, such process is governed by still undefined mechanism.MethodsAt varying differentiation levels, three representative colon cancer cells were cultured in endothelial-inducing conditioned medium: human colon cancer cells HCT116 (HCT116) (poorly differentiated), SW480 (moderately differentiated), and HT29 (well differentiated). We tested for expression of endothelial markers (cluster of differentiation (CD) 31, CD34, and vascular endothelial (VE)-cadherin and their ability to form tube-like structures in 3D culture. We also observed VEGF secretion and expressions of endothelial markers and VEGFRs in HCT116 cells under hypoxia to simulate physiological conditions. In in vitro and in xenotransplantation experiments, VE growth factor receptor 2 (VEGFR2) antagonist SKLB1002 was used to test effect of VEGFR2 in endothelial differentiation of HCT116 cells. Expression levels of VEGFR2 and VE-cadherin were assessed by immunohistochemistry of human colon cancer tissues to evaluate clinicopathological significance of VEGFR2.ResultsAfter culturing in endothelial-inducing conditioned medium, poorly differentiated HCT116 cells expressed endothelial markers and formed tube-like structure in vitro. HCT116 cells secreted more endogenous VEGF and expressed higher VEGFR2 under hypoxia. SKLB1002 impaired endothelial differentiation in vitro and xenotransplantation experiments, suggesting a VEGFR2-dependent mechanism. Increased expression of VEGFR2 correlated with differentiation, metastasis/recurrence, and poor prognosis in 203 human colon cancer samples. Positive correlation was observed between VEGFR2 and VE-cadherin expression.ConclusionsVEGFR2 regulates endothelial differentiation of colon cancer cell and may be potential platform for anti-angiogenesis cancer therapy.