Embryonic Wound Research Articles

AB72. Mysteries of TGF-β paradox in benign and malignant cells.

TGF-β regulates a wide range of biological functions including embryonic development, wound healing, organogenesis, immune modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells, a phenomenon known as TGF-β paradox. To date, the mechanism of this paradox still remains as a scientific mystery. In this review, we present our experience, alone with the literature, in an attempt to offer answers to this mystery. First, we observed that, upon TGF-β engagement, there is a differential activation of Erk between benign and cancer cells. Since activated Erk is a major mediator in tumor progression and metastasis, a differentially activated Erk represents the answer to this mystery. Second, we identified a key player, PP2A-B56α, which is differentially recruited by the activated type I TGF-β receptor (TBRI) in benign and tumor cells, resulting in differential Erk activation. Finally, TGF-β stimulation leads to a suppressed TBRs in tumor cells but not in benign cells. This differentially suppressed TBRs triggers differential recruitment of PP2A-B56α and, thus, differential activation of Erk. The above three events offer the explanation to the mysteries of TGF-β paradox. Understanding the mechanism of TGF-β paradox will help us to predict indolent from aggressive cancers and will help us to develop novel anti-cancer strategies.

Automated multidimensional image analysis reveals a role for Abl in embryonic wound repair.

The embryonic epidermis displays a remarkable ability to repair wounds rapidly. Embryonic wound repair is driven by the evolutionary conserved redistribution of cytoskeletal and junctional proteins around the wound. Drosophila has emerged as a model to screen for factors implicated in wound closure. However, genetic screens have been limited by the use of manual analysis methods. We introduce MEDUSA, a novel image-analysis tool for the automated quantification of multicellular and molecular dynamics from time-lapse confocal microscopy data. We validate MEDUSA by quantifying wound closure in Drosophila embryos, and we show that the results of our automated analysis are comparable to analysis by manual delineation and tracking of the wounds, while significantly reducing the processing time. We demonstrate that MEDUSA can also be applied to the investigation of cellular behaviors in three and four dimensions. Using MEDUSA, we find that the conserved nonreceptor tyrosine kinase Abelson (Abl) contributes to rapid embryonic wound closure. We demonstrate that Abl plays a role in the organization of filamentous actin and the redistribution of the junctional protein β-catenin at the wound margin during embryonic wound repair. Finally, we discuss different models for the role of Abl in the regulation of actin architecture and adhesion dynamics at the wound margin.

Role of Rab11 in planar cell polarity and apical constriction during vertebrate neural tube closure.

Epithelial folding is a critical process underlying many morphogenetic events including vertebrate neural tube closure, however, its spatial regulation is largely unknown. Here we show that during neural tube formation Rab11-positive recycling endosomes acquire bilaterally symmetric distribution in the Xenopus neural plate, being enriched at medial apical cell junctions. This mediolateral polarization was under the control of planar cell polarity (PCP) signaling, was necessary for neural plate folding, and was accompanied by the polarization of the exocyst component Sec15. Our further experiments demonstrate that similar PCP-dependent polarization of Rab11 is essential for ectopic apical constriction driven by the actin-binding protein Shroom and during embryonic wound repair. We propose that anisotropic membrane trafficking plays key roles in diverse morphogenetic behaviors of individual cells and propagates in a tissue by a common mechanism that involves PCP.

ERK and phosphoinositide 3-kinase temporally coordinate different modes of actin-based motility during embryonic wound healing

Embryonic wound healing provides a perfect example of efficient recovery of tissue integrity and homeostasis, which is vital for survival. Tissue movement in embryonic wound healing requires two functionally distinct actin structures: a contractile actomyosin cable and actin protrusions at the leading edge. Here, we report that the discrete formation and function of these two structures is achieved by the temporal segregation of two intracellular upstream signals and distinct downstream targets. The sequential activation of ERK and phosphoinositide 3-kinase (PI3K) signalling divides Xenopus embryonic wound healing into two phases. In the first phase, activated ERK suppresses PI3K activity, and is responsible for the activation of Rho and myosin-2, which drives actomyosin cable formation and constriction. The second phase is dominated by restored PI3K signalling, which enhances Rac and Cdc42 activity, leading to the formation of actin protrusions that drive migration and zippering. These findings reveal a new mechanism for coordinating different modes of actin-based motility in a complex tissue setting, namely embryonic wound healing.

Computational and experimental study of the mechanics of embryonic wound healing

Wounds in the embryo show a remarkable ability to heal quickly without leaving a scar. Previous studies have found that an actomyosin ring (purse string) forms around the wound perimeter and contracts to close the wound over the course of several dozens of minutes. Here, we report experiments that reveal an even faster mechanism which remarkably closes wounds by more than 50% within the first 30s. Circular and elliptical wounds (~100μm in size) were made in the blastoderm of early chick embryos and allowed to heal, with wound area and shape characterized as functions of time. The closure rate displayed a biphasic behavior, with rapid constriction lasting about a minute, followed by a period of more gradual closure to complete healing. Fluorescent staining suggests that both healing phases are driven by actomyosin contraction, with relatively rapid contraction of fibers at cell borders within a relatively thick ring of tissue (several cells wide) around the wound followed by slower contraction of a thin supracellular actomyosin ring along the margin, consistent with a purse string mechanism. Finite-element modeling showed that this idea is biophysically plausible, with relatively isotropic contraction within the thick ring giving way to tangential contraction in the thin ring. In addition, consistent with experimental results, simulated elliptical wounds heal with little change in aspect ratio, and decreased membrane tension can cause these wounds to open briefly before going on to heal. These results provide new insight into the healing mechanism in embryonic epithelia.

Abstract 4268: Resistance to growth inhibition by transforming growth factor-beta is associated with activation of the PI3K-Akt pathway in HPV16-immortalized human keratinocytes at late stages of in vitro progression.

Abstract Transforming growth factor-beta (TGF-ß) plays a vital role in embryonic development, cell proliferation, inflammation and wound repair. The Smad proteins are the central mediators of TGF-ß signal transduction. However, recently several non-Smad pathways (ex., Erk, Jnk, p38 MAPK, PI3K-Akt) have been determined to play key roles in TGF-ß signaling. TGF-ß signaling is often disrupted in cancer, including cervical cancer. Human papillomavirus (HPV) is the main etiological agent in cervical cancer. HPV type 16 (HPV16)-immortalized human keratinocytes (HKc/HPV16) are initially very sensitive to growth inhibition by TGF-ß. However, HKc/HPV16 become increasingly resistant to TGF-ß during in vitro progression, and are completely resistant to TGF-ß-induced growth inhibition at late-stages of transformation, when they exhibit a differentiation resistant phenotype (HKc/DR). Although HKc/DR are completely resistant to the growth inhibitory effects of TGF-ß, some Smad signaling remains. A reporter construct containing tandem repeats of Smad binding elements was induced by TGF-ß in HKc/DR at about 50% of the level observed in HKc/HPV16. Furthermore, TGF-ß was capable of inducing epithelial-mesenchymal transition (EMT) in HKc/DR. To further explore TGF-ß signaling in HKc/HPV16 and HKc/DR, we used phospho specific antibody microarrays from Full Moon BioSystems. These arrays feature phospho and non-phospho pairs of specific antibodies pertinent to the TGF-ß pathway. Protein extracts from HKc/HPV16 and HKc/DR untreated or treated for 90 min with 40 pM TGF-ß were compared on the antibody microarrays. Activation of the Akt pathway by TGF-ß was observed in HKc/DR but not in HKc/HPV16. Similarly, PI3K and mTOR showed activation by TGF-ß in HKc/DR but not HKc/HPV16. We conclude that TGF-ß signals primarily through Smad-dependent pathways to inhibit cell proliferation in HKc/HPV16, but that non-canonical (non-smad) signaling through the PI3K-Akt-mTOR axis predominates in HKc/DR. Citation Format: Rupa Velidandla, Gehana Vaswani, Sangeeta Kowli, Lucia Pirisi-Creek, Kim E. Creek. Resistance to growth inhibition by transforming growth factor-beta is associated with activation of the PI3K-Akt pathway in HPV16-immortalized human keratinocytes at late stages of in vitro progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4268. doi:10.1158/1538-7445.AM2013-4268

Abstract 1160: Inactivated hippo-pathway as a prognostic biomarker in hepatocellular carcinoma.

Abstract The contact inhibition of proliferation and cell movement is crucially important in embryonic development, tissue regeneration, and wound healing for the well-controlled organogenesis. The disruption of contact inhibition results in sustained cell proliferation and uncontrolled cell movement, which is a hallmark of solid tumors. Loss of contact inhibition allows cancer cells to facilitate the invasion of neighboring tissues and metastasis to remote organs. The recently identified Hippo signaling pathway has been implicated in contact inhibition of proliferation as well as organ size control. Indeed, the conditional inactivation of hippo-pathway in liver leads to enlarged liver (massive hepatomegaly) and tumorigenesis (Cell, 2007). Clinically, HCC often shows the huge tumor more than size in 10cm, strongly speculating that inactivation of hippo-pathway plays an important role in HCC progression. However, clinical significance of hippo-pathway in HCC is largely unknown. Here, we investigated the clinical significance of inactivated hippo-pathway, which induce overexpressed oncogenes (YAP/TAZ), using resected 80 HCC samples, and suggested the tumoral-high TAZmRNA expression was a worse prognostic biomarker for HCC patients represented by high proliferative activity. The tumor size in High TAZmRNA expression group (n =24) was significantly larger than that in low expression group (n = 56) (P < 0.05). YAP/TAZ protein over-expression in HCC was associated with high proliferative activity by Ki-67 positive cells. The high TAZmRNA expression group showed significantly worsen disease free survival and overall survival compared with that in low expression group (P = 0.01 and 0.02, respectively). Thus, inactivation of Hippo-pathway plays a crucial role in tumor progression by accelerating proliferative activity, and tumoral TAZmRNA expression level may be a useful prognostic biomarker in HCC. Citation Format: Hiromitsu Hayashi, Hideyuki Kuroki, Naomi Yokoyama, Shigeki Nakagawa, Hidetoshi Nitta, Katsunori Imai, Daisuke Hashimoto, Yoshiaki Ikuta, Akira Chikamoto, Toru Beppu, Hideo Baba. Inactivated hippo-pathway as a prognostic biomarker in hepatocellular carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1160. doi:10.1158/1538-7445.AM2013-1160

Computational and Experimental Study of the Mechanics of Embryonic Wound Healing

The healing of embryonic wounds yields insight into mechanical forces which shape a developing organism. Here we characterize healing of wounds in epithelia of early stage chick embryos, and use a newly developed computational model to investigate underlying cellular-level mechanisms. Early stage chick embryos, consisting of planar epithelial sheets two to three cell layers thick, were harvested and cultured ex ovo. Multicellular wounds were made and allowed to heal. We found that the closure rate of embryonic wounds displayed a two-phase behavior, with rapid constriction lasting about a minute, followed by more gradual contraction until the wound closed. Fluorescent staining revealed that soon after wounding a broad, faint ring of contractile actin and myosin-II encircles the wound. By one minute post wounding this structure gives way to a narrow actomyosin band at the wound border, consistent with a “purse string” healing mechanism observed in other embryonic systems. We hypothesize that contraction of the broad ring is responsible for the initial, rapid phase of wound closure, and that the narrow purse string drives the later slower phase. To test these mechanisms, we implemented both in a finite element computational model. We found that the rapid initial phase of wound closure is consistent only with an isotropic contraction of the broad ring surrounding the wound, and that the slower phase can be accounted for by the formation and circumferential contraction of fibers at the wound margin. Together, these two mechanisms can quantitatively reproduce the observed wound healing dynamics. The results of this integrated experimental and computational investigation suggest that a new mechanism, the isotropic contraction of cells in a broad ring around the wound, works together with an actomyosin contractile ring to close an embryonic wound.

Erk and PI3K temporally coordinate different modes of actin-based motility during embryonic wound healing

SummaryEmbryonic wound healing provides a perfect example of efficient recovery of tissue integrity and homeostasis, which is vital for survival. Tissue movement in embryonic wound healing requires two functionally distinct actin structures: a contractile actomyosin cable and actin protrusions at the leading edge. Here, we report that the discrete formation and function of these two structures is achieved by the temporal segregation of two intracellular upstream signals and distinct downstream targets. The sequential activation of ERK and phosphoinositide 3-kinase (PI3K) signalling divides Xenopus embryonic wound healing into two phases. In the first phase, activated ERK suppresses PI3K activity, and is responsible for the activation of Rho and myosin-2, which drives actomyosin cable formation and constriction. The second phase is dominated by restored PI3K signalling, which enhances Rac and Cdc42 activity, leading to the formation of actin protrusions that drive migration and zippering. These findings reveal a new mechanism for coordinating different modes of actin-based motility in a complex tissue setting, namely embryonic wound healing.

Fibroblast Growth Factor Receptor Inhibitors

Fibroblast growth factor receptors (FGFRs) play an important role in embryonic development, angiogenesis, wound healing, cell proliferation and differentiation. The fibroblast growth factor receptor (FGFR) isoforms have been under intense scrutiny for effective anticancer drug candidates. The fibroblast growth factor (FGF) and its receptor (FGFR) provide another pathway that seems critical to monitoring angiogenesis. Recent findings suggest that FGFR mediates signaling, regulates the PKM2 activity, and plays a crucial role in cancer metabolism. The current review also covers the recent findings on the role of FGFR1 in cancer metabolism. This paper reviews the progress, mechanism, and binding modes of recently known kinase inhibitors such as PD173074, SU series and other inhibitors still under clinical development. Some of the structural classes that will be highlighted in this review include Pyrido[2,3-d]pyrimidines, Indolin- 2-one, Pyrrolo[2,1-f][1,2,4]triazine, Pyrido[2,3-d]pyrimidin-7(8H)-one, and 1,6- Naphthyridin-2(1H)-ones.

Embryonic wound healing: A primer for engineering novel therapies for tissue repair

Scar is the default tissue repair used by the body in response to most injuries-a response that occurs in wounds ranging in seriousness from minor skin cuts to complete severance of the spinal cord. By contrast, before the third trimester of pregnancy embryonic mammals tend to heal without scarring due to a variety of mechanisms and factors that are uniquely in operation during development in utero. The goal of tissue engineering is to develop safe and clinically effective biological substitutes that restore, maintain, or improve tissue function in patients. This review provides a comparative overview of wound healing during development and maturation and seeks to provide a perspective on just how much the embryo may be able teach us in the engineering of new therapies for tissue repair.

Quantitative Evaluation of Fibroblast Migration on a Silk Fibroin Surface and TGFBI Gene Expression

Cell migration plays important roles in natural processes involving embryonic development, inflammation, wound healing, cancer metastasis and angiogenesis. Cell migration on various biomaterials is also believed to improve the rate of wound healing and implant therapies in the tissue-engineering field. This study measured the distance traversed, or mileage, of mouse fibroblasts on a silk fibroin surface. Fibroblasts on the fibroin surface moved with better progress during 24 h than cells on collagen or fibronectin surfaces. Results obtained by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) revealed that fibroblasts on the fibroin surface expressed transforming growth factor β-induced protein (TGFBI), which is an extracellular matrix (ECM) protein, stronger than on other surfaces in the early cell-culture stages. These results demonstrate that the fibroin surface shows higher potential to enhance cell migration and the production of ECM than a collagen or fibronectin surface.

Abstract C97: Studies on the signaling pathway for cancer cell migration based on chemical genomic approach.

Abstract Cell migration is known to be related to not only physiological phenomena such as embryonic development, immune reaction, and wound healing, but also pathological phenomena such as asthma, vascular disease, and cancer metastasis. However, because genetic mutations of each cancer cell causing high migration ability depend on cell types, it still remains unclear that which pathways are the unity of cancer cell migration signaling irrespective of cancer cell types, and which pathways are the diversity depend on cell types. The aim of this study is to reveal the diversity and unity of regulatory signaling for cancer cell migration based on chemical genomic approach. To understand the diversity and unity of regulatory signaling for cancer cell migration, the effects of 38 small compounds, whose target protein are already identified, on cell migration ability of 10 types of cancer cells were assessed quantitatively by wound healing assay. Two-way hierarchical clustering was done on migration ability profile by small compounds or cancer cell types. As a result, cancer cells tested in this study were classified into three clusters (group A∼C). Interestingly, epidermoid carcinoma A431 cells and esophageal squamous carcinoma EC109 cells (group B) were classified different cluster from esophageal squamous carcinoma TE8 cells and thyroid medullary carcinoma T.T cells (group C), whereas all four cell lines were induced migration by EGF stimulation. On the other hand, compounds were clustered into five clusters (cluster I∼V). The compounds classified into cluster I (e.g., V-ATPase inhibitor and bisphosphonates) showed little inhibitory effect on all types of cell migration. The compounds clustered into cluster II (e.g., EGFR inhibitor and ROCK inhibitor) showed stronger inhibitory effect on the migration of group B and C than A. The compounds classified into cluster III (e.g., JNK inhibitor) showed strong inhibitory effect on all types of cell migration tested in this study. The compounds clustered into cluster IV (e.g., PI3K inhibitors and mTOR inhibitor) showed stronger inhibitory effect on the migration of group B than C. On the contrary, the compounds classified into cluster V (e.g., MEK inhibitor and p38 inhibitors) showed stronger inhibitory effect on group C than B. These results indicate that JNK play the common role in cancer cell migration, and belonging to cluster II, IV, and V would have different function in each type of cancer cell migration. We are now investigating how these molecules actually operate in the signaling pathway in each cancer cell, and trying network analysis by the combination of chemical biology and systems biology. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C97.

Abstract 237: MET receptor is a potential new target for cervical carcinoma treatment

Abstract Introduction: Cervical carcinoma (CC) is the major cause of death among women suffering from neoplastic disease especially in the developing countries. The highest mortality is observed in patients with late diagnosis and metastatic disease. MET protooncogene encodes a tyrosine kinase receptor for hepatocyte growth factor (HGF). MET activation triggers a complex biological program including stimulation of cell proliferation, motility and protection from apoptosis. This program plays an important role during embryonic development and wound healing, but abnormal MET activity contribute to cancer development and progression. Therefore, new therapeutic strategies inhibiting MET signaling have been sought. Objectives: The aim of this study was to examine the influence of MET inhibition on growth and metastatic ability of cervical carcinoma cell. Materials and Methods: CC cell line (HTB35) was transduced with MET shRNA and LacZ shRNA expressing viruses and selected with blasticidin. To check genes expression real-time PCR, western blot and flow cytometry were used. Proliferation, cell cycle and apoptosis was studied. Stress fibers organization, adhesion and migration were evaluated using using falloidin staining, adhesion assay and chemotaxis assay respectively. The level of various protein phosphorylation was estimated by western blot. Results: We showed that downregulation of MET expression in HTB-35 cell line causes: (i) the reduction in cell proliferation resulting from altered cell cycle progression, but not from enhanced apoptosis, (ii) changes in actin cytoskeleton organization, (iii) the increased expression of E-cadherin, (iv) the decrease of mRNA levels in the genes responsible for malignant phenotype (such as c-myc, CXCR4 and Slug), and (v) the increased expression of genes involved in EMT and metastasis (including Snail, Slug, Twist, MMP-2, MMP-9 and HIF-1α). Performed in vitro studies have not shown any significant effect of MET inhibition on adhesive ability of HTB-35 cervical carcinoma cell line. However, the decreased migration of MET negative cells was observed. Summary: Our results strongly, indicate that MET receptor plays an important role in stimulating growth and metastasis of HTB-35 cervical carcinoma cell line. Thus, inhibition of HGF-MET receptor axis could be used in the future as the new therapeutic strategy to block cervical carcinoma development and progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 237. doi:10.1158/1538-7445.AM2011-237

Abstract 4160: Evaluating epithelial-to-mesenchymal transition (EMT) in the EL1-luc/EL1-SV40 T-antigen transgenic mouse model of pancreatic cancer

Abstract Epithelial-to-mesenchymal transition (EMT) is a biological function important in normal cellular processes such as embryonic development and wound healing. In cancer it is thought that the tumor cell machinery can re-activate these normal pathways resulting in more aggressive and invasive tumors. The loss of E-cadherin and the gain of vimentin are hallmarks which identify the process of EMT and have been shown to correlate with poor prognosis in multiple solid tumor types. While many preclinical models are utilized to evaluate mechanisms of tumorigenesis few in vivo models evaluating parameters of EMT have been described. The EL1-luc/EL1-SV40 T-antigen transgenic mouse represents a model of pancreatic cancer whereby mice develop tissue specific, spontaneous and bioluminescent pancreatic tumors. To evaluate whether EMT occurs in the EL1-luc/EL1-SV40 T-antigen model in vivo, we collected primary pancreatic tissue from male mice between 10 and 21 weeks of age. The tissue was formalin fixed, paraffin embedded and then utilized for histopathological endpoints such as Hemotoxylin and Eosin staining as well as immunohistochemistry for markers known to be involved in EMT such as E-cadherin and vimentin. We found the tumors to express both markers and become very heterogeneous over time. In early tumors E-cadherin expression is membrane localized and very high. Over time there are areas of the tumors that have reduced or lost E-cadherin expression. Vimentin expression was highly variable but when present tended to be highly expressed. In many of the later stage tumors there was substantial heterogeneity reflected by the appearance of multiple cell types within a tumor. We utilized the Aperio (Aperio Technologies, Vista, CA) slide scanner and software system to evaluate serial sections of tumor samples and found that in some sections of the tumor E-cadherin is present and vimentin is absent, whereas in other areas of the tumor vimentin is present in the absence of E-cadherin. Additionally, we identified areas of the tumor that seem to be expressing both markers which suggests that the EL1-luc/EL1-SV40 T-antigen transgenic mouse may recapitulate many aspects of EMT observed in vivo, thus offering a model system to study the signaling and molecular changes necessary for this process during cancer progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4160.

Abstract 4216: Activation of Akt and β-catenin pathways are required for the sustention of cancer stem cell-like characteristics generated by epithelial-mesenchymal transition

Abstract Approximately 90% of cancer deaths are caused by metastasis. The increased motility and invasiveness of tumor cells is reminiscent of the processes at the epithelial-mesenchymal transition (EMT), which is essential for morphogenetic events in embryonic development, tissue remodeling, and wound healing. EMT not only confers tumor cells with a distinct advantage for metastatic dissemination but also provides cancer stem cell-like characteristics for their proliferation and survival. However, the molecular mechanism for maintenance of these cancer stem cell-like traits by EMT remains unclear. In this study, we generated two stable transfectants in breast cancer MCF7 and cervical cancer Hela cell lines with expression of Twist, a key transcriptional factor of EMT. We found that expression of Twist induced a morphological EMT changes in these cells by downregulating the expression of E-cadherin and ZO-1 and by increasing vimentin and N-cadherin expression. We also showed that the CD44highCD24low subpopulation in these stable transfectants, which is associated with cancer stem cells properties, was significantly increased. Consistent with these findings, expression of stem cell marker ALDH1 was also elevated in these cells. The increased stem cell-like traits in Twist expression clones correlated with the tumorsphere formation in these cells. Strikingly, we found that β-catenin and Akt pathways were activated in these Twist-expressing transfectants. The nuclear accumulation of β-catenin correlated with the expression of CD44. Knockdown of β-catenin expression or inhibition of the Akt pathway significantly decreased the expression of CD44. Together, our results indicate that the activation of β-catenin and Akt pathway are required for the sustention of cancer stem cell-like traits generated by EMT. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4216.

Fibroblast growth factor receptors (FGFR) as possible therapeutic targets in human non-small cell lung cancer

The fibroblast growth factors (FGFs) are a large family of peptide growth factors playing essential roles in embryonic development, tissue maintenance and wound healing. FGFs interact with target cells by binding to four high-affinity receptor tyrosine kinases (RTK) termed FGFR1-4. Based on the proliferative and anti-apoptotic as well as pro-angiogenic functions of the FGF/FGFR signal module, it is not surprising that deregulations occur at multiple levels in many types of human cancer. Recently, it got obvious that FGF/FGFR signals might also be hyperactivated in non-small cell lung cancer (NSCLC) by diverse molecular mechanisms leading to autocrine support of tumour cell proliferation, migration and survival as well as paracrine activities including neo-angiogenesis. Additionally, FGF/FGFR signals turned out to be involved in therapy resistance against not only classical chemotherapy but also novel targeted anti-NSCLC agents like inhibitors of the epidermal growth factor receptor (EGFR). This suggests that FGF/FGFR inhibitors might represent a novel component for combined NSCLC therapy approaches.

Dermal Transforming Growth Factor-β Responsiveness Mediates Wound Contraction and Epithelial Closure

Stromal-epithelial interactions are important during wound healing. Transforming growth factor-beta (TGF-beta) signaling at the wound site has been implicated in re-epithelization, inflammatory infiltration, wound contraction, and extracellular matrix deposition and remodeling. Ultimately, TGF-beta is central to dermal scarring. Because scarless embryonic wounds are associated with the lack of dermal TGF-beta signaling, we studied the role of TGF-beta signaling specifically in dermal fibroblasts through the development of a novel, inducible, conditional, and fibroblastic TGF-beta type II receptor knockout (Tgfbr2(dermalKO)) mouse model. Full thickness excisional wounds were studied in control and Tgfbr2(dermalKO) back skin. The Tgfbr2(dermalKO) wounds had accelerated re-epithelization and closure compared with controls, resurfacing within 4 days of healing. The loss of TGF-beta signaling in the dermis resulted in reduced collagen deposition and remodeling associated with a reduced extent of wound contraction and elevated macrophage infiltration. Tgfbr2(dermalKO) and control skin had similar numbers of myofibroblastic cells, suggesting that myofibroblastic differentiation was not responsible for reduced wound contraction. However, several mediators of cell-matrix interaction were reduced in the Tgfbr2(dermalKO) fibroblasts, including alpha1, alpha2, and beta1 integrins, and collagen gel contraction was diminished. There were associated deficiencies in actin cytoskeletal organization of vasodilator-stimulated phosphoprotein-containing lamellipodia. This study indicated that paracrine and autocrine TGF-beta dermal signaling mechanisms mediate macrophage recruitment, re-epithelization, and wound contraction.

19-P041 The role of IP3 signalling during embryonic wound healing in Xenopus

19-P041 The role of IP3 signalling during embryonic wound healing in Xenopus

03-P098 Integrating the genetics, mechanics and phenomenology of embryonic wound healing

03-P098 Integrating the genetics, mechanics and phenomenology of embryonic wound healing