FGF Signaling Pathways Research Articles

Effects of Klotho on fibrosis and cancer: A renal focus on mechanisms and therapeutic strategies.

Klotho is a membrane-bound protein predominantly expressed in the kidney, where it acts as a permissive co-receptor for Fibroblast Growth Factor 23. In its shed form, Klotho exerts anti-fibrotic effects in several tissues. Klotho-deficient mice spontaneously develop fibrosis and Klotho deficiency exacerbates the disease progression in fibrotic animal models. Furthermore, Klotho overexpression or supplementation protects against fibrosis in various models of renal and cardiac fibrotic disease. These effects are mediated at least partially by the direct inhibitory effects of soluble Klotho on TGFβ1 signaling, Wnt signaling, and FGF2 signaling. Soluble Klotho, as present in the circulation, appears to be the primary mediator of anti-fibrotic effects. Similarly, through inhibition of the TGFβ1, Wnt, FGF2, and IGF1 signaling pathways, Klotho also inhibits tumorigenesis. The Klotho promoter gene is generally hypermethylated in cancer, and overexpression or supplementation of Klotho has been found to inhibit tumor growth in various animal models. This review focuses on the protective effects of soluble Klotho in inhibiting renal fibrosis and fibrosis in distant organs secondary to renal Klotho deficiency. We also discuss the structure-function relationships of Klotho domains and biological effects in the context of potential targeted treatment strategies.

Abstract 1805: Antitumor activity of lenvatinib mesilate in human hepatocellular carcinoma preclinical models

Abstract Hepatocellular carcinoma (HCC) is a one of the leading causes of cancer death worldwide; however systemic therapeutic option for unresectable HCC is limited. Liver carcinogenesis is a complex process and various pathways have been found to be deregulated. Of those pathways, aberrant activation of fibroblast growth factor 19 (FGF19)/FGF receptor 4 (FGFR4) axis has been hypothesized to participate in the development of HCC with poor prognosis. Lenvatinib mesilate (lenvatinib) is an orally administered multi-targeted tyrosine kinase inhibitor (TKI) that selectively inhibits vascular endothelial growth factor receptors (VEGFR)1-3, FGFR1-4, platelet-derived growth factor receptor (PDGFR)α, RET, and KIT. In this study, we investigated the activities of lenvatinib against human HCC cells with or without amplification/overexpression of FGF19 gene in vitro and in vivo. Lenvatinib inhibited in vitro proliferation of human HCC cell lines Hep 3B2.1-7 and HuH-7 with IC50 values of 0.23 and 0.42 μmol/L (0.086 and 0.16 μmol/L as unbound IC50), respectively, whereas it did not show potent antiproliferative activity against PLC/PRF/5 (IC50 >10 μmol/L). Both Hep 3B2.1-7 and HuH-7 were reported to have an amplification of FGF19 gene and their cell growth was dependent on FGF19/FGFR4 axis. Sorafenib inhibited in vitro proliferation of the 3 HCC cell lines with IC50 values of 2.2 - 5.3 μmol/L (0.59 - 1.4 μmol/L as estimated unbound IC50 based on previously reported protein binding). Next, antitumor activity was evaluated in 2 human HCC cell line (PLC/PRF/5 and Hep 3B2.1-7) xenograft models. Lenvatinib treatments at 1 - 100 mg/kg resulted in tumor growth inhibition with a maximal antitumor effect giving a minimum T/C value (minT/C) of 14% via its antiangiogenic activity in the PLC/PRF/5 model, and at 3 - 30 mg/kg with minT/C of 31% in the Hep 3B2.1-7 model. Sorafenib showed significant antitumor effect at doses ≥30 mg/kg with minT/C of 30% in the PLC/PRF/5 model, and at 10 and 30 mg/kg with minT/C of 47% in the Hep 3B2.1-7 model. Finally, we tested antitumor activity in HCC patient-derived xenograft (PDX) model (LI0050), and PDX-derived cell line (LIXC-012) xenograft model with FGF19 overexpression in mice. Lenvatinib significantly inhibited the tumor growth of LI0050 at 10 and 30 mg/kg with minT/C of 33%, and that of LIXC-012 at 3 - 30 mg/kg with minT/C of 25%. Treatment with sorafenib at 30 mg/kg was intolerable in LI0050 model, and sorafenib showed significant antitumor activity at 30 mg/kg with T/C of 55%, but not 10 mg/kg in the LIXC-012 model. In conclusion, these results indicate that lenvatinib has potent preclinical antitumor activity in human HCC xenograft models with or without amplification/overexpression of FGF19. Furthermore, the maximum antitumor effect of lenvatinib was greater than that of sorafenib in this study. Direct effect of lenvatinib on proliferation of HCC cells with an aberrant FGF signaling pathway in tumor warrants further investigation. Citation Format: Masahiro Matsuki, Yuji Yamamoto, Taisuke Hoshi, Takayuki Kimura, Yasuhiro Funahashi, Junji Matsui. Antitumor activity of lenvatinib mesilate in human hepatocellular carcinoma preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1805. doi:10.1158/1538-7445.AM2017-1805

Identification and characterization of a rich population of CD34+ mesenchymal stem/stromal cells in human parotid, sublingual and submandibular glands

Mesenchymal stem/stromal cells (MSCs) play crucial roles in maintaining tissue homeostasis during physiological turnovers and injuries. Very little is known about the phenotype, distribution and molecular nature of MSCs in freshly isolated human salivary glands (SGs) as most reports have focused on the analysis of cultured MSCs. Our results demonstrate that the cell adhesion molecule CD34 was widely expressed by the MSCs of human major SGs, namely parotid (PAG), sublingual (SLG) and submandibular (SMG) glands. Further, gene expression analysis of CD34+ cells derived from fetal SMGs showed significant upregulation of genes involved in cellular adhesion, proliferation, branching, extracellular matrix remodeling and organ development. Moreover, CD34+ SMG cells exhibited elevated expression of genes encoding extracellular matrix, basement membrane proteins, and members of ERK, FGF and PDGF signaling pathways, which play key roles in glandular development, branching and homeostasis. In vitro CD34+ cell derived SG-MSCs revealed multilineage differentiation potential. Intraglandular transplantation of cultured MSCs in immunodeficient mice led to their engraftment in the injected and uninjected contralateral and ipsilateral glands. Engrafted cells could be localized to the stroma surrounding acini and ducts. In summary, our data show that CD34+ derived SG-MSCs could be a promising cell source for adoptive cell-based SG therapies, and bioengineering of artificial SGs.

Abstract MIP-058: YAP, VIA INTERACTIONS WITH THE FGF SIGNALING PATHWAY, REGULATES TUMORIGENESIS OF FALLOPIAN TUBE SECRETORY EPITHELIAL CELLS

Abstract INTRODUCTION: Accumulating evidence indicates that ovarian high-grade serous carcinoma (HGSC) originates from Fallopian tube secretory epithelial cells (FTSECs). Our recent studies indicated that the Hippo/YAP signaling pathway contributes to transformation of ovarian surface epithelial cells. However, whether this pathway is also involved in the initiation and progression of FTSEC-derived ovarian HGSC has not been examined. AIMS: The present study aims to determine whether the Hippo/YAP signaling pathway plays a role in initiation and progression of Fallopian tube-derived HGSC and the potential mechanism(s) by which YAP regulates FTSEC tumorigenesis. RESULTS: Immunohistochemical analysis showed that YAP expression was very low in normal human fallopian tube and ovarian tissues. However, YAP immunosignals significantly increased in ovarian HGSCs, cancerous and inflammatory fallopian tube tissues. Data extracted from multidimensional human cancer genomics datasets revealed that the YAP and TEADs (the major target transcription factors of YAP) genes are frequently amplified and/or up-regulated, while the upstream tumor suppressor genes such as NF1 and LATS1, are frequently deleted and/or mutated in ovarian HGSC tissues. Overexpression of YAP in immortalized non-tumorigenic FTSECs promoted cell proliferation in both 2D and 3D culture systems, induced colony formation in soft agar, and drove tumorigenesis in athymic nude mice. Pathohistological and biochemical analyses clearly indicated that tumors derived from the FTSECs resembled ovarian HGSC. In addition, our mechanistic studies showed that activation of YAP in human FTSECs upregulated the expression of fibroblast growth factors (FGF1, FGF2) and their receptors (FGFR1, FGFR2, FGFR3 and FGFR4). Intriguingly, we found that the activated FGF signaling in turn suppressed the Hippo pathway and activated YAP protein. Consistent with this result, treatment of FTSECs with YAP antagonist (Verteporfin) and/or FGFR inhibitor (BGI398) not only blocked YAP-induced FTSECs transformation, but also suppressed tumor cell growth and induced tumor cell death in a human HGSC xenograft model. CONCLUSION: Our results demonstrate that the disruption of the Hippo/YAP signaling pathway contributes to the carcinogenesis of the fallopian tube secretory epithelial cells. The Hippo/YAP and FGF signaling pathways formed an autocrine/paracrine positive feedback loop to drive the progression of the FTSECs-derived HGSC. Evidence in this study strongly suggests that combined targeting of YAP and FGFRs represents a novel therapeutic strategy for ovarian HGSCs. Citation Format: Chunbo He, Guohua Hua, Xiangmin Lv, Zhengfeng Wang, Ronny I. Drapkin, John S. Davis, Cheng Wang. YAP, VIA INTERACTIONS WITH THE FGF SIGNALING PATHWAY, REGULATES TUMORIGENESIS OF FALLOPIAN TUBE SECRETORY EPITHELIAL CELLS [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr MIP-058.

Role of GALNT14 in lung metastasis of breast cancer.

Aberrant expression of the polypeptide N-acetyl-galactosaminyltransferase (GALNTs) has been associated with cancer, but their function(s) in metastasis remains elusive. We have recently identified GALNT14, one of the O-GalNAc glycosylation-initiating enzymes, as a prognostic marker for pulmonary relapse in breast cancer patients. Furthermore, we showed that GALNT14 promotes lung metastasis by the following novel mechanisms: 1) enhancing metastasis initiation by inhibiting the anti-metastatic effect of BMP produced from the lung stroma, 2) exploiting growth signals (e.g. FGF) supplied by macrophages, for their growth into macrometastases in the lung environment. These multi-faceted roles of GALNT14 in lung metastasis are achieved by GALNT14-mediated inhibition and activation of the BMP and FGF signaling pathways, respectively. The link among GALNT14, its downstream pathways and lung metastasis, provides us with an opportunity to develop effective therapeutic intervention for breast cancer.

Distinct Requirements for FGFR1 and FGFR2 in Primitive Endoderm Development and Exit from Pluripotency

Activation of the FGF signaling pathway during preimplantation development of the mouse embryo is known to be essential for differentiation of the inner cell mass and the formation of the primitive endoderm (PrE). We now show using fluorescent reporter knockin lines that Fgfr1 is expressed in all cell populations of the blastocyst, while Fgfr2 expression becomes restricted to extraembryonic lineages, including the PrE. We further show that loss of both receptors prevents the development of the PrE and demonstrate that FGFR1 plays a more prominent role in this process than FGFR2. Finally, we document an essential role for FGFRs in embryonic stem cell (ESC) differentiation, with FGFR1 again having a greater influence than FGFR2 in ESC exit from the pluripotent state. Collectively, these results identify mechanisms through which FGF signaling regulates inner cell mass lineage restriction and cell commitment during preimplantation development.

Chick derived induced pluripotent stem cells by the poly-cistronic transposon with enhanced transcriptional activity.

Induced pluripotent stem (iPS) cell technology lead terminally differentiated cells into the pluripotent stem cells through the expression of defined reprogramming factors. Although, iPS cells have been established in a number of mammalian species, including mouse, human, and monkey, studies on iPS cells in avian species are still very limited. To establish chick iPS cells, six factors were used within the poly-cistronic reprogramming vector (PB-R6F), containing M3O (MyoD derived transactivation domain fused with Oct3/4), Sox2, Klf4, c-Myc, Lin28, and Nanog. The PB-R6F derived iPS cells were alkaline-phosphatase and SSEA-1 positive, which are markers of pluripotency. Elevated levels of endogenous Oct3/4 and Nanog genes were detected in the established iPS cells, suggesting the activation of the FGF signaling pathway is critical for the pluripotent status. Histological analysis of teratoma revealed that the established chick iPS cells have differentiation ability into three-germ-layer derived tissues. This is the first report of establishment of avian derived iPS cells with a single poly-cistronic transposon based expression system. The establishment of avian derived iPS cells could contribute to the genetic conservation and modification of avian species.

Identification of microRNAs associated with glioma diagnosis and prognosis.

The sensitivity and specificity of microRNAs (miRNAs) for diagnosing glioma are controversial. We therefore performed a meta-analysis to systematically identify glioma-associated miRNAs. We initially screened five miRNA microarray datasets to evaluate the differential expression of miRNAs between glioma and normal tissues. We next compared the expression of the miRNAs in different organs and tissues to assess the sensitivity and specificity of the differentially expressed miRNAs in the diagnosis of glioma. Finally, pathway analysis was performed using GeneGO. We identified 27 candidate miRNAs associated with glioma initiation, progression, and patient prognosis. Sensitivity and specificity analysis indicated miR-15a, miR-16, miR-21, miR-23a, and miR-9 were up-regulated, while miR-124 was down-regulated in glioma. Ten signaling pathways showed the strongest association with glioma development and progression: the p53 pathway feedback loops 2, Interleukin signaling pathway, Toll receptor signaling pathway, Parkinson's disease, Notch signaling pathway, Cadherin signaling pathway, Apoptosis signaling pathway, VEGF signaling pathway, Alzheimer disease-amyloid secretase pathway, and the FGF signaling pathway. Our results indicate that the integration of miRNA, gene, and protein expression data can yield valuable biomarkers for glioma diagnosis and treatment. Indeed, six of the miRNAs identified in this study may be useful diagnostic and prognostic biomarkers in glioma.

Convergence of signaling pathways underlying habenular formation and axonal outgrowth in zebrafish.

The habenular nuclei are a conserved integrating center in the vertebrate epithalamus, where they modulate diverse behaviors. Despite their importance, our understanding of habenular development is incomplete. Time-lapse imaging and fate mapping demonstrate that the dorsal habenulae (dHb) of zebrafish are derived from dbx1b-expressing (dbx1b+ ) progenitors, which transition into cxcr4b-expressing neuronal precursors. The precursors give rise to differentiated neurons, the axons of which innervate the midbrain interpeduncular nucleus (IPN). Formation of the dbx1b+ progenitor population relies on the activity of the Shh, Wnt and Fgf signaling pathways. Wnt and Fgf function additively to generate dHb progenitors. Surprisingly, Wnt signaling also negatively regulates fgf8a, confining expression to a discrete dorsal diencephalic domain. Moreover, the Wnt and Fgf pathways have opposing roles in transcriptional regulation of components of the Cxcr4-chemokine signaling pathway. The chemokine pathway, in turn, directs the posterior outgrowth of dHb efferents toward the IPN and, when disrupted, results in ectopic, anteriorly directed axonal projections. The results define a signaling network underlying the generation of dHb neurons and connectivity with their midbrain target.

Contribution of cranial neural crest cells to mouse skull development.

The mammalian skull vault is a highly regulated structure that evolutionally protects brain growth during vertebrate development. It consists of several membrane bones with different tissue origins (e.g. neural crest-derived frontal bone and mesoderm-derived parietal bone). Although membrane bones are formed through intramembranous ossification, the neural crest-derived frontal bone has superior capabilities for osteoblast activities and bone regeneration via TGF, BMP, Wnt, and FGF signaling pathways. Neural crest (NC) cells are multipotent, and once induced, will follow specific paths to migrate to different locations of the body where they give rise to a diverse array of cell types and tissues. Recent studies using genetic mouse models have greatly advanced our knowledge of NC cell induction, proliferation, migration and differentiation. Perturbations or disruptions of neural crest patterning lead to severe developmental defects or diseases. This review summarizes recent discoveries including novel functions of genes or signaling molecules that are capable of governing developmental processes of neural crest patterning, which may function as a gene regulatory network in controlling skull development. The proposed regulatory network will be important to understand how the signaling pathways and genes converge to regulate osteoblast activities and bone formation, which will be beneficial for the potential identification of molecular targets to prevent or alleviate human diseases or disorders involving defective neural crest development.

Directed Differentiation of Mouse Embryonic Stem Cells Into Inner Ear Sensory Epithelia in 3D Culture.

The inner ear sensory epithelium harbors mechanosensory hair cells responsible for detecting sound and maintaining balance. This protocol describes a three-dimensional (3D) culture system that efficiently generates inner ear sensory epithelia from aggregates of mouse embryonic stem (mES) cells. By mimicking the activations and repressions of key signaling pathways during in vivo inner ear development, mES cell aggregates are sequentially treated with recombinant proteins and small molecule inhibitors for activating or inhibiting the Bmp, TGFβ, Fgf, and Wnt signaling pathways. These stepwise treatments promote mES cells to sequentially differentiate into epithelia representing the non-neural ectoderm, preplacodal ectoderm, otic placodal ectoderm, and ultimately, the hair cell-containing sensory epithelia. The derived hair cells are surrounded by a layer of supporting cells and are innervated by sensory neurons. This in vitro inner ear organoid culture system may serve as a valuable tool in developmental and physiological research, disease modeling, drug testing, and potential cell-based therapies.

成骨分化相关信号通路的研究进展

目的：成骨分化是骨质形成的基础，也是骨代谢的关键步骤。近年来，关于成骨分化的分子机制，国内外取得了许多突破性的进展。故围绕成骨分化相关信号通路研究进展这一要点进行综述和分析。方法：检索近几年国内外成骨分化及成骨相关信号通路研究的文献，并作总结分析。结果：发现多条信号通路参与成骨分化，其中，BMP-SMAD、Wnt/β-Catenin、Notch、Hedgehog、MAPK、FGF信号通路在成骨分化过程中最为关键。多条信号通路间存在着相互作用，构成了一个复杂的调控网络，但由于研究手段的局限，成骨分化相关信号通路的具体作用机制仍不明了。结论：若能说明这些信号通路各自发挥作用的机制及各条通路之间的相互关系，对阐明成骨分化的具体机制具有重要意义。 Objective: Osteogenesis is the foundation of bone formation and key procedure of bone metabolism. In recent years, major progress was made in the molecular mechanism of osteogenesis at home and abroad. Therefore, the mechanism and research progress of osteogenesis-related signaling pathways was reviewed. Methods: Literature about ossification and osteogenesis-relate signaling pathways in recent years were reviewed and analyzed. Results: Several signaling pathways have been found osteogenesis-related, among them, BMP-SMAD, Wnt/β-Catenin, Notch, Hedgehog, MAPK and FGF signaling pathways play the leading role in bone-formation. Besides, a complex regulatory network is composed of interactions between multiple signaling pathways. However, the specific mechanism of osteogenesis-related signaling pathways is still unclear because of limited research methods. Conclusion: To make clear the mechanism of these signaling pathways respectively and their interactions is of great significance for illustrating the complete mechanism of osteogenesis.

The chromatin modifier Satb1 regulates cell fate through Fgf signalling in the early mouse embryo.

The separation of embryonic from extra-embryonic tissues within the inner cell mass to generate the epiblast (EPI), which will form the new organism, from the primitive endoderm (PE), which will form the yolk sac, is a crucial developmental decision. Here, we identify a chromatin modifier, Satb1, with a distinct role in this decision. Satb1 is differentially expressed within 16-cell-stage embryos, with higher expression levels in the inner cell mass progenitor cells. Depleting Satb1 increases the number of EPI cells at the expense of PE. This phenotype can be rescued by simultaneous depletion of both Satb1 and Satb2, owing to their antagonistic effect on the pluripotency regulator Nanog. Consequently, increasing Satb1 expression leads to differentiation into PE and a decrease in EPI, as a result of the modulation of expression of several pluripotency- and differentiation-related genes by Satb1. Finally, we show that Satb1 is a downstream target of the Fgf signalling pathway, linking chromatin modification and Fgf signalling. Together, these results identify a role for Satb1 in the lineage choice between pluripotency and differentiation and further our understanding of early embryonic lineage segregation.

Keratin mediated attachment of stem cells to augment cardiomyogenic lineage commitment

The objective of this work was to develop a simple surface modification technique using keratin derived from human hair for efficient cardiomyogenic lineage commitment of human mesenchymal stem cells (hMSCs). Keratin was extracted from discarded human hair containing both the acidic and basic components along with the heterodimers. The extracted keratin was adsorbed to conventional tissue culture polystyrene surfaces at different concentration. Keratin solution of 500μg/ml yielded a well coated layer of 12±1nm thickness with minimal agglomeration. The keratin coated surfaces promoted cell attachment and proliferation. Large increases in the mRNA expression of known cardiomyocyte genes such as cardiac actinin, cardiac troponin and β-myosin heavy chain were observed. Immunostaining revealed increased expression of sarcomeric α-actinin and tropomyosin whereas Western blots confirmed higher expression of tropomyosin and myocyte enhancer factor 2C in cells on the keratin coated surface than on the non-coated surface. Keratin promoted DNA demethylation of the Atp2a2 and Nkx2.5 genes thereby elucidating the importance of epigenetic changes as a possible molecular mechanism underlying the increased differentiation. A global gene expression analysis revealed a significant alteration in the expression of genes involved in pathways associated in cardiomyogenic commitment including cytokine and chemokine signaling, cell–cell and cell-matrix interactions, Wnt signaling, MAPK signaling, TGF-β signaling and FGF signaling pathways among others. Thus, adsorption of keratin offers a facile and affordable yet potent route for inducing cardiomyogenic lineage commitment of stem cells with important implications in developing xeno-free strategies in cardiovascular regenerative medicine.

Involvement of PI3K and PKA pathways in mouse tongue epithelial differentiation

In mice, tongue epithelial differentiation is mainly regulated by the interactions among various signalling molecules including Fgf signalling pathways. However, the subsequent signalling modulations for epithelial maturation, initiated by Fgf signalling, remain to be elucidated. Therefore, we employed an in vitro tongue organ cultivation system along with the applications of various pharmacological inhibitors against the intracellular signalling molecules of Fgf signalling pathways, including H89, LY294002, PD98059, and U0126. Following treatments with LY294002 and H89, inhibitors for PI3K and PKA, respectively, the decreased thickness of the tongue epithelium was observed along with the alteration in cell proliferative and apoptotic patterns. Meanwhile, cultivated tongues treated with MEK inhibitor U0126 or PD98059 showed significantly decreased cell proliferation in the tongue epithelium and the mesenchyme. Based on these results, we suggest that the tongue epithelium is differentiated into multiple epithelial cell layers via the PI3K and PKA pathways in tissue-specific manner during the epithelial-mesenchymal interactions.

SwitchFinder - a novel method and query facility for discovering dynamic gene expression patterns.

BackgroundBiological systems and processes are highly dynamic. To gain insights into their functioning time-resolved measurements are necessary. Time-resolved gene expression data captures temporal behaviour of the genes genome-wide under various biological conditions: in response to stimuli, during cell cycle, differentiation or developmental programs. Dissecting dynamic gene expression patterns from this data may shed light on the functioning of the gene regulatory system. The present approach facilitates this discovery. The fundamental idea behind it is the following: there are change-points (switches) in the gene behaviour separating intervals of increasing and decreasing activity, whereas the intervals may have different durations. Elucidating the switch-points is important for the identification of biologically meanigfull features and patterns of the gene dynamics.ResultsWe developed a statistical method, called SwitchFinder, for the analysis of time-series data, in particular gene expression data, based on a change-point model. Fitting the model to the gene expression time-courses indicates switch-points between increasing and decreasing activities of each gene. Two types of the model - based on linear and on generalized logistic function - were used to capture the data between the switch-points. Model inference was facilitated with the Bayesian methodology using Markov chain Monte Carlo (MCMC) technique Gibbs sampling. Further on, we introduced features of the switch-points: growth, decay, spike and cleft, which reflect important dynamic aspects. With this, the gene expression profiles are represented in a qualitative manner - as sets of the dynamic features at their onset-times. We developed a Web application of the approach, enabling to put queries to the gene expression time-courses and to deduce groups of genes with common dynamic patterns.SwitchFinder was applied to our original data - the gene expression time-series measured in neuroblastoma cell line upon treatment with all-trans retinoic acid (ATRA). The analysis revealed eight patterns of the gene expression responses to ATRA, indicating the induction of the BMP, WNT, Notch, FGF and NTRK-receptor signaling pathways involved in cell differentiation, as well as the repression of the cell-cycle related genes.ConclusionsSwitchFinder is a novel approach to the analysis of biological time-series data, supporting inference and interactive exploration of its inherent dynamic patterns, hence facilitating biological discovery process. SwitchFinder is freely available at https://newbioinformatics.eu/switchfinder.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-016-1391-0) contains supplementary material, which is available to authorized users.

Tbx2 regulates anterior neural specification by repressing FGF signaling pathway

During early embryogenesis, FGF signals regulate the antero-posterior (AP) patterning of the neural plate by promoting posterior cell fates. In particular, BMP signal-mediated attenuation of FGF pathway plays a critical role in the determination of the anterior neural region. Here we show that Tbx2, a T-box transcriptional repressor regulates anterior neural specification by suppressing FGF8 signaling pathway in Xenopus embryo. Tbx2 is expressed in the anterior edge of the neural plate in early neurulae. Overexpression and knockdown of Tbx2 induce expansion and reduction in the expression of anterior neural markers, respectively. It also suppresses FGF8-induced ERK phosphorylation and neural caudalization. Tbx2, which is a target gene of BMP signal, down-regulates FGF8 signaling by inhibiting the expression of Flrt3, a positive regulator of this pathway. We found that Tbx2 binds directly to the T-box element located in the promoter region of Flrt3 gene, thereby interfering with the activity of the promoter. Consistently, Tbx2 augmentation of anterior neural formation is inhibited by co-expression of Flrt3. Furthermore, disruption of the anterior-most structures such as eyes in Tbx2-depleted embryos can be rescued by inhibition of Flrt3 function or FGF signaling. Taken together, our results suggest that Tbx2 mediates BMP signal to down-regulate FGF signaling pathway by repressing Flrt3 expression for anterior tissue formation.

Binding of human recombinant mutant soluble ectodomain of FGFR2IIIc to c subtype of FGFRs: implications for anticancer activity.

FGFRs are considered essential targets for cancer therapy. We previously reported that msFGFR2c, a Ser252Trp mutant soluble ectodomain of FGFR2IIIc, inhibited tumor growth by blocking FGF signaling pathway. However, the underlying molecular mechanism is still obscure. In this study, we reported that msFGFR2c but not wild-type soluble ectodomain of FGFR2IIIc (wsFGFR2c) could selectively bind to c subtype of FGFRs in the presence of FGF-2. Thermodynamic analysis demonstrated that msFGFR2c bound to wsFGFR2c in the presence of FGF-2 with a K value of 6.61 × 105 M−1. Molecular dynamics simulations revealed that the mutated residue Trp252 of msFGFR2c preferred a π-π interaction with His254 of wsFGFR2c. Concomitantly, Arg255 of msFGFR2c and Glu250 of wsFGFR2c adjusted their conformations and formed three H-bonds. These two interactions therefore stabilized the final structure of wsFGFR2c and msFGFR2c heterocomplex. In FGFR2IIIc-positive/high FGF-2-secreted BT-549 cells, msFGFR2c significantly inhibited the proliferation and induced apoptosis by the blockage of FGF-2-activated FGFRs phosphorylation, also the growth and angiogenesis of its xenograft tumors implanted in chick embryo chorioallantoic membrane model. While weaker the above inhibitory effects of msFGFR2c were observed on FGFR2IIIc-negative/low FGF-2-secreted MCF-7 and MDA-MB-231 cell lines in vitro and in vivo. Moreover, msFGFR2c significantly inhibited the proliferation of FGFR1IIIc-positive NCI-H1299 lung cancer cells by the suppression of FGF-2-induced FGFR1 activation and suppressed the growth of NCI-H1299 transplanted tumors in nude mice. In sum, msFGFR2c is a potential anti-tumor agent targeting FGFR2c/FGFR1c-positive tumor cells. These findings also provide a molecular basis for msFGFR2c to disrupt the activation of FGF signaling.

Inhibition of FGF Signalling Pathway Augments the Expression of Pluripotency and Trophoblast Lineage Marker Genes in Porcine Parthenogenetic Blastocyst.

The consistent failure to isolate bona fide pluripotent cell lines from livestock indicates that the underlying mechanisms of early lineage specification are poorly defined. Unlike other species, the contrivances of segregation have been comprehensively studied in the mouse. In mouse, FGF/MAPK signalling pathway dictates the segregation of hypoblast (primitive endoderm). However, it is not evident whether this mechanism is also conserved in livestock. Here, in this study, we examined the roles of FGF/MAP kinase signalling pathways in porcine parthenogenetic embryos during the early development. Porcine parthenogenetic embryos were cultured in the medium addition with FGFR inhibitor BGJ398 (10μm) or DEMOS. Pluripotency- and lineage-related gene expressions in the early porcine embryos were determined. Compared to control, total cell numbers on day 7 were significantly higher (55±5.96 vs 47±1.97, p<0.05) in embryos cultured in the presence of BGJ398, but had no significant effect on the rate of blastocyst development (47% vs 44%, p>0.05). Nonetheless, BGJ398 treatment significantly augmented the expression of pluripotency and trophoblast marker genes (SOX2, OCT4, KLF4 and CDX2), but did not significantly change the expression of NANOG and hypoblast marker gene (GATA4). Furthermore, the addition of FGF signalling agonist (FGF2) during the embryo development significantly decreased the expression of pluripotency and trophoblast marker genes (SOX2, NANOG, KLF4 and CDX2), but no significant effect on the expression of OCT4 and GATA4 was observed. Here, we exhibit that inhibition of FGF signalling could improve the quality of the porcine embryo and escalate the chance to capture pluripotency. Besides, it also promotes the trophoblast development of porcine parthenogenetic embryo. In addition, the data suggested that FGF signalling pathway is dispensable for the segregation of hypoblast and epiblast lineages in porcine embryo during the early development.

Comprehensive investigation of aberrant microRNA profiling in bladder cancer tissues.

There has been accumulative evidence that microRNAs (miRNAs) play essential roles in the tumorigenesis and progression of bladder cancer. However, individual studies and small sample size caused discrepant outcomes. Thus, the current study focused on a comprehensive profiling of all differentially expressed miRNAs in a total of 519 bladder cancer tissue samples, based on miRNA microarray data. Altogether, 11 prioritized miRNAs stated by 21 published microarray datasets, including five down-regulated (miR-133a-3p, miR-1-3p, miR-99a-5p, miR-490-5p, and miR-133b) and six up-regulated candidate miRNAs (miR-182-5p, miR-935, miR-518e-3p, miR-573, miR-100-3p, and miR-3171) were analyzed with vote-counting strategy and a Robust Rank Aggregation method. Subsequently, miRNA in silico target prediction and potential pathway enrichment analysis were performed to investigate the prospective molecular mechanism of miRNAs in the tumorigenesis of bladder cancer. We found that most of the relative pathways of the aberrantly expressed miRNAs found in the current study were closely correlated with different biological processes, cellular components, molecular functions, cancer pathogeneses, and some cell signalings, such as Wnt signaling, insulin/IGF, PI3 kinase, and FGF signaling pathways. Hence, a comprehensive overview on the miRNA expression pattern in bladder cancer tissues was gained by the current study. These miRNAs might be involved in the tumorigenesis and deterioration of bladder cancer.