Promotes Tumor Cell Migration Research Articles

Tumor Necrosis Factor α Reduces SNAP29 Dependent Autolysosome Formation to Increase Prion Protein Level and Promote Tumor Cell Migration.

Tumor Necrosis Factor α (TNFα) is best known as a mediator of inflammation and immunity, and also plays important roles in tumor biology. However, the role of TNFα in tumor biology is complex and not completely understood. In a human melanoma cell line, M2, and a lung carcinoma cell line, A549, TNFα up-regulates prion protein (PrP) level, and promotes tumor cell migration in a PrP dependent manner. Silencing PRNP abrogates TNFα induced tumor cell migration; this phenotype is reversed when PRNP is re-introduced. Treatment with TNFα activates nuclear factor kappa B (NF-κB) signaling, which then mitigates autophagy by reducing the expression of Forkhead Box P3 (FOXP3). Down regulation of FOXP3 reduces the transcription of synaptosome associated protein 29 (SNAP29), which is essential in the fusion of autophagosome and lysosome creating autolysosome. FOXP3 being a bona fide transcription factor for SNAP29 is confirmed in a promoter binding assay. Accordingly, silencing SNAP29 in these cell lines also up-regulates PrP, and promotes tumor cell migration without TNFα treatment. But, when SNAP29 or FOXP3 is silenced in these cells, they are no longer respond to TNFα. Thus, a reduction in autophagy is the underlying mechanism by which expression of PrP is up-regulated, and tumor cell migration is enhanced upon TNFα treatment. Disrupting the TNFα-NF-κB-FOXP3-SNAP29 signaling axis may provide a therapeutic approach to mitigate tumor cell migration.

Ran GTPase is an independent prognostic marker in malignant melanoma which promotes tumour cell migration and invasion

AimsRan GTPase is involved in nucleocytoplasmic shuttling of proteins and is overexpressed in several cancers. The expression of Ran in malignant melanoma (MM) and its functional activity have not been...

HDAC6 promotes growth, migration/invasion, and self-renewal of rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is a devastating pediatric sarcoma. The survival outcomes remain poor for patients with relapsed or metastatic disease. Effective targeted therapy is lacking due to our limited knowledge of the underlying cellular and molecular mechanisms leading to disease progression. In this study, we used functional assays in vitro and in vivo (zebrafish and xenograft mouse models) to demonstrate the crucial role of HDAC6, a cytoplasmic histone deacetylase, in driving RMS tumor growth, self-renewal and migration/invasion. Treatment with HDAC6-selective inhibitors recapitulates the HDAC6 loss-of-function phenotypes. HDAC6 regulates cytoskeletal dynamics to promote tumor cell migration and invasion. RAC1, a Rho family GTPase, is an essential mediator of HDAC6 function, and is necessary and sufficient for RMS cell migration and invasion. High expression of RAC1 correlates with poor clinical prognosis in RMS patients. Targeting the HDAC6-RAC1 axis represents a promising therapeutic option for improving survival outcomes of RMS patients.

Fatty acid synthase promotes breast cancer metastasis by mediating changes in fatty acid metabolism.

Fatty acid metabolism is closely associated with the occurrence and development of tumors. The aim of the present study was to investigate whether the key enzyme involved in fatty acid synthesis, fatty acid synthase (FASN), mediates fatty acid changes that affect the activity and migration of breast cancer cells, and whether specific fatty acids play a role in tumor metastasis. The difference in serum fatty acid profiles between patients with invasive ductal carcinoma (IDC) and healthy controls was evaluated by gas chromatography-mass spectrometry (GC-MS) fatty acid profile analysis, and it was revealed that five types of fatty acids may be potential tumor markers in IDC. Immunohistochemistry and GC-MS analysis revealed that FASN expression affected the serum fatty acid profiles of patients with IDC. Following FASN knockdown, the migration of SK-Br-3 breast cancer cells was inhibited, and the contents of various fatty acids both inside and outside the cell decreased, while the contents of various fatty acids inside and outside the cell increased following FASN overexpression. The results of the present study revealed that the expression level of FASN affected the content of fatty acids in IDC tissues and breast cancer cell lines, and that FASN-mediated changes in specific fatty acids promoted tumor cell migration.

Expression of fibroblast growth factor receptor like 1 protein in oral squamous cell carcinoma and its influence on tumor cell proliferation and migration

This study aims to investigate the expression of fibroblast growth factor receptor like 1 (FGFRL1) in oral squamous cell carcinoma (OSCC) and reveals its association with tumor cell proliferation and migration. Western blot was performed to detect the expression of FGFRL1 protein in OSCC tissues, adjacent normal tissues, OSCC cell lines and normal epithelial cells. After knocking down of FGFRL1 in HN4 cells, CCK-8 and Ki67 assays were performed to detect cell proliferation, wounding healing assay and transwell were performed to detect cell-migration. Western blot was used to detect the expression of protein related to epithelial-mesenchymal transition (EMT). The expression of FGFRL1 in OSCC tissues was higher than that in adjacent nontumor tissues, respectively (t=2.820, P=0.047 8). Moreover, the expression of FGFRL1 in OSCC cells was higher than that in HOK cells. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that FGFRL1 expression of FGFRL1 RNA in HOK cells was lower than that in OSCC cells. HN4 cells transfected with FGFRL1 siRNA were included in the experimental group, whereas HN4 cells treated with NC siRNA were included in the control group. CCK-8 experiment showed no significant difference between the experimental and control groups with regard to proliferation ability at 48 h (P=0.478 1) and 72 h (P=0.334 2). Migration experiment showed that the wound healing areas in the experimental group after 12 h (P=0.022 8), 24 h (P=0.005 1), and 36 h (P=0.009 5）were smaller than that in the control group. Transwell invasion assay showed that the number of invaded cells in the experimental group after 16 h (P=0.008 7) and 24 h (P=0.008 6) were lower than that in the control group. Knocking-down FGFRL1 up-regulated the expression of E-cadherin and down-regulated the expression of N-cadherin and Vimentin in HN4 cells. FGFRL1 expression in the OSCC tissues was significantly higher than that in the adjacent nontumor tissues. FGFRL1 expression in the OSCC cells was significantly higher than that in the HOK cells, and FGFRL1 had no effect on cell proliferation but promoted tumor cell migration and EMT.

Cancer-Associated Fibroblasts in Mycosis Fungoides Promote Tumor Cell Migration and Drug Resistance through CXCL12/CXCR4

Cancer cells are known to reprogram normal fibroblasts into cancer-associated fibroblasts (CAFs) to act as tumor supporters. The presence and role of CAFs in mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, are unknown. This study sought to characterize CAFs in MF and their cross talk with the lymphoma cells using primary fibroblast cultures from punch biopsies of patients with early-stage MF and healthy subjects. MF cultures yielded significantly increased levels of FAPα, a CAF marker, and CAF-associated genes and proteins: CXCL12 (ligand of CXCR4 expressed on MF cells), collagen XI, and matrix metalloproteinase 2. Cultured MF fibroblasts showed greater proliferation than normal fibroblasts in exvivo experiments. A coculture with MyLa cells (MF cell line) increased normal fibroblast growth, reduced the sensitivity of MyLa cells to doxorubicin, and enhanced their migration. Inhibiting the CXCL12/CXCR4 axis increased doxorubicin-induced apoptosis of MyLa cells and reduced MyLa cell motility. Our data suggest that the fibroblasts in MF lesions are more proliferative than fibroblasts in normal skin and that CAFs protect MF cells from doxorubicin-induced cell death and increase their migration through the secretion of CXCL12. Reversing the CAF-mediated tumor microenvironment in MF may improve the efficiency of anticancer therapy.

Exosome-Derived Differentiation Antagonizing Non-Protein Coding RNA Promotes Tumor Recurrences in Hepatitis C-Related Hepatocellular Carcinoma

Background & Aims: Differentiation antagonizing non-protein coding RNA (DANCR) associated with various types of neoplasms. Hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) (HCV-HCC) has a high risk of recurrence. We explored the role of DANCR in HCV-related hepatocarcinogenesis and identified potential therapeutic targets and non-invasive prognostic markers for long-term outcome of HCV-HCC after surgical resection. Methods: DANCR relevant to HCV-HCC were identified by comparative RNA-sequencing of tumor (T) and adjacent non-tumor (ANT) tissues in a screening set, validated using real-time PCR Target lncRNAs in tissues and serum exosomes were used to predict HCC recurrence of HCV-HCC after curative surgical resection in a large application cohort. Exosome-Derived DANCR was explored using JFH1-infected cells and macrophages. Results: We confirmed that DANCR was upregulated by HCV infection and identified as the lncRNA most relevant to HCV-HCC in tumor as compared to ANT tissues. In 183 HCV-HCC patients followed for 10 years after curative HCC resection, the expression level of circulating exosomal DANCR was positively associated with HCC recurrence and was the most predictive factor associated with HCC recurrence and mortality (hazard ratio/95% confidence intervals: 7.0/4.3–11.6 and 2.7/1.5–5.1, respectively). In vitro study further demonstrated that exosomal DANCR was positively associated with mesenchymal-associated β-catenin expression in HCV infectious hepatocyte and macrophages, which might consequently promote tumor cell migration and invasion abilities in the tumor microenvironment. Conclusions: The lncRNA DANCR is highly relevant to disease progression of HCV-HCC Furthermore, circulating exosomal DANCR might serve as a non-invasive prognostic biomarker for HCV-HCC. Funding Statement: This study supported by the grants from the Ministry of Science Technology (MOST) grant (108-2314-B-037-079-MY3) (106-2221-E-039-011-MY3); China medical University (CMU108-MF-93), (CMU108-Z-02), (CMU108-S-22); Kaohsiung Medical University (KMU-Q108009), (KMUQ109005), (108-CCH-KMU-001); partially by Kaohsiung Medical University Research Grant KMU-TC108A04 and KMU-TC108B06. This study was partially supported by of Liquid Biopsy and of Cancer Research, Kaohsiung Medical University, and the Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B) from The Featured Areas Research Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan. Declaration of Interests: All authors declare no support from any organization other than the below mentioned ones for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years; and no other relationships or activities that could appear to have influenced the submitted work. Hence, all authors declare themselves to be independent from funders with respect to this manuscript. Ethics Approval Statement: The study protocol was approved by the Institutional Review Board at each hospital and the TLCN User Committee and was carried out in accordance with the Declaration of Helsinki and the guidelines of the International Conference on Harmonization for Good Clinical Practice.

Arginase-1+ Exosomes from Reprogrammed Macrophages Promote Glioblastoma Progression.

Interactions between tumor cells and tumor-associated macrophages (TAMs) are critical for glioblastoma progression. The TAMs represent up to 30% of the glioblastoma mass. The role of TAMs in tumor progression and in the mechanisms underlying tumor growth remain unclear. Using an in vitro model resembling the crosstalk between macrophages and glioblastoma cells, we show that glioblastoma-derived exosomes (GBex) reprogram M1 (mediate pro-inflammatory function) and M2 (mediate anti-inflammatory function) macrophages, converting M1 into TAMs and augmenting pro-tumor functions of M2 macrophages. In turn, these GBex-reprogrammed TAMs, produce exosomes decorated by immunosuppressive and tumor-growth promoting proteins. TAM-derived exosomes disseminate these proteins in the tumor microenvironment (TME) promoting tumor cell migration and proliferation. Mechanisms underlying the promotion of glioblastoma growth involved Arginase-1+ exosomes produced by the reprogrammed TAMs. A selective Arginase-1 inhibitor, nor-NOHA reversed growth-promoting effects of Arginase-1 carried by TAM-derived exosomes. The data suggest that GBex-reprogrammed Arginase-1+ TAMs emerge as a major source of exosomes promoting tumor growth and as a potential therapeutic target in glioblastoma.

Serum level of lncRNA TUSC7 in patients with esophageal squamous cell carcinoma and its role in promoting tumor cell migration and invasion

To investigate serum levels of long non-coding RNA (lncRNA) TUSC7 in patients with esophageal squamous cell carcinoma (ESCC), its association with clinicopathological parameters and its role in promoting tumor metastasis and invasion. Serum samples were collected from 60 patients with ESCC admitted between January, 2017 and May, 2019, with 60 age- and gender-matched healthy subjects as the control group. Serum level of TUSC7 in ESCC patients and its expression in 4 ESCC cell lines was detected with RT-qPCR. The association of serum TUSC7 level with the clinicopathological features of the patients was analyzed. KYSE-30 cell models with TUSC7 overexpression or knockdown were established, and the proliferation of the cells was examined with MTT assay and their migration and invasion were assessed using wound healing and Transwell assays. Western blotting was used to detect the cellular expressions of the proteins associated with epithelial-mesenchymal transition (EMT). The patients with ESCC had significantly lower serum TUSC7 level than the healthy control subjects (P < 0.05). The ESCC cell lines also expressed lower levels of TUSC7 than normal cells (P < 0.05). Serum TUSC7 level was negatively correlated with tumor staging, lymph node metastasis and infiltration (P < 0.05) but was not significantly correlated with other clinicopathological parameters in ESCC patients. In the invitro cell experiment, overexpression of TUSC7 in KYSE-30 cells significantly inhibited cell migration and invasion (P < 0.05), enhanced the expression of the EMT marker protein E-cadherin and lowered the expressions of N-cadherin, Vimentin and MMP9 (P < 0.05); knocking down TUSC7 in the cells produced the opposite effects. The down-regulation of TUSC7 expression in the serum of ESCC patients and in ESCC cell lines is associated with the metastasis of ESCC and promotes tumor cell migration and invasion by promoting EMT, indicating the potential of serum TUSC7 level as a molecular marker for diagnosis, treatment and metastasis monitoring of ESCC.

MicroRNA‑103a‑3p promotes metastasis by targeting TPD52 in salivary adenoid cystic carcinoma.

Salivary adenoid cystic carcinoma (SACC) exhibits slow continuous growth, frequent local recurrences and a high incidence of blood metastasis, with advanced lung metastasis frequently occurring and being among the primary causes of mortality. MicroRNAs(miR) serve a significant role in the initiation and development of cancer and may be tumour‑specific molecular targets. However, the role of miR‑103a‑3p in SACC remains largely unknown. In the present study, the expression levels of miR‑103a‑3p and tumour protein D52 (TPD52) were detected by reverse transcription‑quantitative PCR. In addition, wound‑healing assays, Transwell assays and mouse models of lung metastasis were used to investigate the biological functions exerted by miR‑103a‑3p. The present results suggested that miR‑103a‑3p expression was significantly upregulated in SACC samples. Gain‑of‑function and loss‑of‑function studies in SACC cells demonstrated that miR‑103a‑3p acted as an oncogene by promoting tumour cell migration invitro and lung metastasis invivo. Dual‑luciferase reporter gene assays indicated that miR‑103a‑3p exerted its regulatory functions by binding to the 3'untranslated region of TPD52 mRNA. TPD52 overexpression rescued the effect of miR‑103a‑3p on promoting SACC cell migration, suggesting that miR‑103a‑3p acted as an oncogene to promote cancer metastasis by directly targeting TPD52. Thus, the newly identified miR‑103a‑3p/TPD52 axis contributes to the understanding of SACC pathogenesis, providing insights into the identification of novel biomarkers or potential therapeutic targets in SACC.

NEUROD1 is highly expressed in extensive-disease small cell lung cancer and promotes tumor cell migration

IntroductionSmall cell lung cancer (SCLC) manifests high-grade neuroendocrine features, and the transcription factors ASCL1 and NEUROD1 play an important role in the survival and growth as well as contribute to the heterogeneity of SCLC cells. The relative abundance of ASCL1 and NEUROD1 mRNAs differs among human SCLC cell lines, but the expression pattern of the encoded proteins in clinical SCLC specimens and its relation to clinicopathologic characteristics of patients have been unclear. Materials and MethodsWe retrospectively analyzed tumor specimens collected from 95 previously untreated SCLC patients between June 1988 and December 2017 for ASCL1 and NEUROD1 expression by immunohistochemical staining. We also examined the effects of overexpression or depletion of NEUROD1 on cell migration in SCLC cell lines. ResultsOverall survival did not differ significantly between SCLC patients with a high or low expression score for ASCL1 or NEUROD1 in their tumor samples. The staining score for NEUROD1 was significantly higher in extensive-disease (ED) samples than in limited-disease (LD) samples (median of 160 versus 80 out of a maximum of 300, P = 0.0389), and the proportion of tumors with an ASCL1highNEUROD1low phenotype was smaller for ED-SCLC. Overexpression or depletion of NEUROD1 in SCLC cell lines promoted or attenuated cell migratory activity, respectively. ConclusionOur clinical and experimental data indicate that the expression of NEUROD1 is increased in ED-SCLC and promotes the migration of SCLC cells. NEUROD1 might thus contribute to metastasis in ED-SCLC.

Qigesan inhibits esophageal cancer cell invasion and migration by inhibiting Gas6/Axl-induced epithelial-mesenchymal transition.

Qigesan (QGS) has been used to effectively treat esophageal cancer (EC) for decades in China, but the mechanism by which it suppresses EC metastasis remains unknown. In this study, we examined the effects of QGS on EC cell mobility. Using immunohistochemistry and immunofluorescence, expression of Gas6 and Axl, which promote tumor cell migration and invasion, was examined in carcinoma tissues and adjacent normal tissues from EC patients. Levels of Gas6, Axl, and the Gas6/Axl complex were also examined in ECA109 and TE13 EC cells treated with QGS. In addition, immunofluorescent staining and quantitative protein analysis were used to examine E-cadherin, N-cadherin, and Snail levels in ECA109 and TE13 EC cells after QSG administration, and cell mobility was assessed. The results demonstrated that levels of Gas6 and Axl expression are higher in EC tissues than in adjacent normal tissues. Moreover, QGS decreased Gas6/Axl levels, increased E-cadherin expression, decreased Snail and N-cadherin expression, and inhibited epithelial-mesenchymal transition (EMT) in EC cells. QGS thus suppresses EMT in EC by inhibiting Gas6/Axl binding.

Gamma-synuclein as a potential novel prognostic marker promoting tumor cell migration in biliary tract carcinoma.

577 Background: Biliary tract carcinoma (BTC) is a highly malignant tumor, but the detailed pathological mechanism of its development and progression remain ill-defined. Gamma-synuclein (SNCG) promotes invasive behavior in pancreatic cancer and a range of other cancers, and SNCG expression is reportedly a prognostic factor. However, the role of SNCG in BTC remains unknown. Consequently, we investigated the clinicopathological significance and function of SNCG in BTC. Methods: Using surgically resected BTC specimens from 149 patients with adenocarcinoma [extrahepatic cholangiocarcinoma (ECC) (n =98); intrahepatic cholangiocarcinoma (ICC) (n =51)], we immunohistochemically evaluated SNCG positivity and checked for correlations with clinicopathological factors and outcomes. Furthermore, cell lines with high expressions of SNCG were selected from 17 BTC cell lines by using immunohistochemistry and qPCR. Cell proliferation and migration assays were then performed in the presence and absence of SNCG (silenced using). Results: SNCG expression was found in 32 of 149 (21.4%) BTC patients. SNCG expression was significantly correlated with poorly differentiated tumor ( P = 0.001) and lymph node metastases ( P = 0.001). SNCG positivity was also correlated with poorly differentiated tumor in both ECC and ICC ( P = 0.008 and P = 0.03, respectively), but was correlated with lymph node metastases only in ECC ( P = 0.003). Multivariate analyses identified SNCG expression as an independent prognostic factor of poor overall survival ( P = 0.008) and poor recurrence-free survival (RFS) ( P = 0.006). SNCG expression in both ECC and ICC was significantly associated with poor prognosis in univariate analysis, and multivariate analysis identified SNCG as an independent prognostic factor of poor RFS for ECC (P = 0.03). High SNCG expression was found in 3 BTC cell lines (NCC-BD1, NCC-BD3, and NCC-CC6-1). Functional analysis revealed that SNCG silencing by siRNA suppressed cell migration significantly in NCC-BD1 and NCC-CC6-1 and downregulated cell proliferation in NCC-CC6-1. Conclusions: Our results suggest that SNCG may promote tumor cell activity and is potentially a novel prognostic marker in BTC.

FAK signaling in cancer-associated fibroblasts promotes breast cancer cell migration and metastasis by exosomal miRNAs-mediated intercellular communication.

Cancer-associated fibroblasts (CAFs) are activated fibroblasts that constitute the major components of tumor microenvironment (TME) and play crucial roles in tumor development and metastasis. Here, we generated fibroblast-specific inducible focal adhesion kinase (FAK) knockout (cKO) mice in a breast cancer model to study potential role and mechanisms of FAK signaling in CAF to promote breast cancer metastasis in vivo. While not affecting primary tumor development and growth, FAK deletion significantly suppressed breast cancer metastasis in vivo. Analyses of CAFs derived from cKO mice as well as human CAFs showed that FAK is required for their activity to promote mammary tumor cell migration. We further showed that FAK ablation in CAFs decreased their exosome amount and functions to promote tumor cell migration and other activities, which could contribute to the reduced metastasis observed in cKO mice. Lastly, profiling of miRs from CAF exosomes showed alterations of several exosomal miRs in FAK-null CAFs, and further analysis suggested that miR-16 and miR-148a enriched in exosomes from FAK-null CAFs contribute to the reduced tumor cell activities and metastasis. Together, these results identify a new role for FAK signaling in CAFs that regulate their intercellular communication with tumor cells to promote breast cancer metastasis.

Indoor dust extracellular vesicles promote cancer lung metastasis by inducing tumour necrosis factor-α

ABSTRACT Indoor pollutants are important problems to public health. Among indoor pollutants, indoor dust contains extracellular vesicles (EVs), which are associated with pulmonary inflammation. However, it has not been reported whether indoor dust EVs affect the cancer lung metastasis. In this study, we isolated indoor dust EVs and investigated their roles in cancer lung metastasis. Upon intranasal administration, indoor dust EVs enhanced mouse melanoma lung metastasis in a dose-dependent manner in mice. Pre-treatment or co-treatment of indoor dust EVs significantly promoted melanoma lung metastasis, whereas post-treatment of the EVs did not. In addition, the lung lysates from indoor dust EV-treated mice significantly increased tumour cell migration in vitro. We observed that tumour necrosis factor-α played important roles in indoor dust EV-mediated promotion of tumour cell migration in vitro and cancer lung metastasis in vivo. Furthermore, Pseudomonas EVs, the main components of indoor dust EVs, and indoor dust EVs showed comparable effects in promoting tumour cell migration in vitro and cancer lung metastasis in vivo. Taken together, our results suggest that indoor dust EVs, at least partly contributed by Pseudomonas EVs, are potential promoting agents of cancer lung metastasis.

Targeting eIF5A2 inhibits prostate carcinogenesis, migration, invasion and metastasis in vitro and in vivo

ABSTRACT Overexpression of eukaryotic initiation factor- 5A2 (eIF5A2) has been implicated in promoting tumor cell migration and invasion in many cancers. However, whether eIF5A2 could be as the target for prostate cancer (PCa) treatment is still unknown. In this study, small interfering RNA specific for eIF5A2 (eIF5A2 siRNA) and lentivector for eIF5A2 shRNA (Lv-eIF5A2 shRNA) was performed to down-regulate eIF5A2 expression in PCa PC-3 M IE8 cells and in animal tumor model, respectively. The biological function of eIF5A2 siRNA or Lv-eIF5A2 shRNA on PC-3 M IE8 cell growth, apoptosis, migration, invasion and lung metastasis were explored. The results showed that targeting eIF5A2 inhibited PC-3 M IE8 cell invasion, migration, proliferation and increased cell apoptosis in vitro, and inhibited tumor growth and lung metastasis in vivo. Analysis of eIF5A2 signaling pathways in the clonal derivatives showed a decrease in MMP-2 and MMP-9 activation and increase in bcl-2 expression. We therefore concluded that therapies targeting the eIF5A2 signaling pathway may be more effective to prevent organ metastasis and primary tumor formation.

LncRNA H19-Derived miR-675-3p Promotes Epithelial-Mesenchymal Transition and Stemness in Human Pancreatic Cancer Cells by targeting the STAT3 Pathway.

Objective: The functional role and mechanism of the long noncoding RNA (lncRNA) H19 in regulating human pancreatic cancer (PC) cell stemness and invasion have not been completely elucidated. This study aimed to evaluate the role of H19 in regulating the stemness, epithelial-mesenchymal transition (EMT), invasion and chemosensitivity of PC cells.Methods: The sphere-forming ability was assessed using serum-free floating-culture systems. Chemosensitivity was evaluated via CCK-8 and flow cytometry assays in vitro. Migration and invasion were evaluated by transwell assays. The expression of stemness and EMT markers was detected by flow cytometry, qRT-PCR and western blot analyses. Xenograft initiation, growth and sensitivity were examined; Ki-67 nuclear staining intensity was evaluated by immunohistochemistry; and in situ apoptosis was evaluated by a TUNEL assay.Results: H19 played an important role in maintaining PC cell stemness. Upregulated H19 expression in CAPAN-1 cells promoted tumor cell migration, invasion, EMT and chemoresistance. In contrast, downregulated H19 expression in PANC-1 cells yielded the opposite results. These effects were mediated by positively modulating the STAT3 pathway. Furthermore, SOCS5, an endogenous inhibitor of the STAT3 pathway, was a direct target of miR-675-3p, which was positively regulated by H19 in PC cells.Conclusions: The H19/miR-675-3p signaling axis plays a critical role in maintaining the EMT process and stemness of PC cells by directly targeting SOCS5 to activate the STAT3 pathway. These data provide new insights into the oncogenic function of H19 in human PC and reveal potential targets for the development of optimal treatment approaches for this disease.

GATA3 suppresses human fibroblasts-induced metastasis of clear cell renal cell carcinoma via an anti-IL6/STAT3 mechanism

Tumorigenesis and metastasis depend on intricate interactions between genetically altered tumor cells and their surrounding microenvironment. It is, however, unclear regarding the molecular mechanisms underlying the progress and metastasis of human clear-cell renal cell carcinoma in the microenvironment with fibroblasts. In this work, we investigated the effect of normal fibroblasts on the metastasis of renal cancer and the relevant signaling pathways. We isolated normal fibroblasts from normal renal tissues and used normal fibroblast-conditioned medium culture renal cancer cells. The CCK-8 and transwell assays showed that normal fibroblasts conditioned medium significantly enhanced ccRCC cell migration. IL6 mediated the cross talk between normal fibroblasts and the cancer cells, and promoted tumor cell migration through the STAT3 pathway. In contrast, GATA3 was downregulated at both mRNA and protein levels in the normal fibroblast-conditioned medium treated with renal cancer cells, but upregulated in adjacent normal tissues. GATA3 overexpression significantly reduced STAT3 phosphorylation and attenuated the migration in both renal cancer cell and IL6-stimulated renal cancer cell. Taken together, our findings suggest that the IL6/STAT3 pathway plays a crucial role in the normal fibroblast-enhanced clear-cell renal cell carcinoma metastasis, while GATA3 may mitigate this effect by inhibiting IL6/STAT3 signaling.

Dimerization and phosphorylation of Lutheran/basal cell adhesion molecule are critical for its function in cell migration on laminin

Tumor cell migration depends on the interactions of adhesion proteins with the extracellular matrix. Lutheran/basal cell adhesion molecule (Lu/BCAM) promotes tumor cell migration by binding to laminin α5 chain, a subunit of laminins 511 and 521. Lu/BCAM is a type I transmembrane protein with a cytoplasmic domain of 59 (Lu) or 19 (Lu(v13)) amino acids. Here, using an array of techniques, including site-directed mutagenesis, immunoblotting, FRET, and proximity-ligation assays, we show that both Lu and Lu(v13) form homodimers at the cell surface of epithelial cancer cells. We mapped two small-XXX-small motifs in the transmembrane domain as potential sites for monomers docking and identified three cysteines in the cytoplasmic domain as being critical for covalently stabilizing dimers. We further found that Lu dimerization and phosphorylation of its cytoplasmic domain were concomitantly needed to promote cell migration. We conclude that Lu is the critical isoform supporting tumor cell migration on laminin 521 and that the Lu:Lu(v13) ratio at the cell surface may control the balance between cellular firm adhesion and migration.

Tumor Cell Mechanosensing During Incorporation into the Brain Microvascular Endothelium.

Tumor metastasis to the brain occurs in approximately 20% of all cancer cases and often occurs due to tumor cells crossing the blood-brain barrier (BBB). The brain microenvironment is comprised of a soft hyaluronic acid (HA)-rich extracellular matrix with an elastic modulus of 0.1-1kPa, whose crosslinking is often altered in disease states. To explore the effects of HA crosslinking on breast tumor cell migration, we developed a biomimetic model of the human brain endothelium, consisting of brain microvascular endothelial cell (HBMEC) monolayers on HA and gelatin (HA/gelatin) films with different degrees of crosslinking, as established by varying the concentration of the crosslinker Extralink. Metastatic breast tumor cell migration speed, diffusion coefficient, spreading area, and aspect ratio increased with decreasing HA crosslinking, a mechanosensing trend that correlated with tumor cell actin organization but not CD44 expression. Meanwhile, breast tumor cell incorporation into endothelial monolayers was independent of HA crosslinking density, suggesting that alterations in HA crosslinking density affect tumor cells only after they exit the vasculature. Tumor cells appeared to exploit both the paracellular and transcellular routes of trans-endothelial migration. Quantitative phenotyping of HBMEC junctions via a novel Python software revealed a VEGF-dependent decrease in punctate VE-cadherin junctions and an increase in continuous and perpendicular junctions when HBMECs were treated with tumor cell-secreted factors. Overall, our quantitative results suggest that a combination of biochemical and physical factors promote tumor cell migration through the BBB.