Search

Supplementary Video S1: PF-228's effect on NCI-446 SCLC cell line migration. NCI-H446 cell lines were grown to confluence in 12-well plates. Cell monolayers were wounded using a micropipette tip and floating cells were washed off with PBS. After overnight incubation, PF-228 at a concentration of 3µM or DMSO was added to culture medium. Cell movements within wounded area were monitored for 12h starting from the time drug was added using a Zeiss Axiovert 200M microscope (Zeiss, Thornwood, NY) at x200 magnification. Images were captured every 15-minutes from five different fields randomly selected in each well. They show that PF-228 decreased migration velocity in NCI-H446 cell lines.

Supplementary Figure S1: Western blot densitometric quantifications. Supplementary Figure S2: FAK Inhibitor 14 (Inh14) and PF-562,271 (PF-271)'s effects on FAK expression/activity, cell proliferation, and apoptosis in NCI-H446 SCLC cell lines. Supplementary Figure S3: PF-573,228 (PF-228)'s effects on FAK expression/activity, cell proliferation, and apoptosis in NCI-H82 SCLC cell lines transduced with FAK shRNA. Supplementary Figure S4: phospho-Paxillin expression in NCI-H446 SCLC cell line where FAK has been inhibited with pharmacological and genetic methods.

Small cell lung cancer (SCLC) has a poor prognosis. Focal adhesion kinase (FAK) is a non–receptor tyrosine kinase regulating cell proliferation, survival, migration, and invasion, which is overexpressed and/or activated in several cancers, including SCLC. We wanted to determine whether FAK contributes to SCLC aggressive behavior. We first evaluated the effect of FAK small-molecule inhibitor PF-573,228 in NCI-H82, NCI-H146, NCI-H196, and NCI-H446 SCLC cell lines. PF-573,228 (0.1–5 μmol/L) inhibited FAK activity by decreasing phospho-FAK (Tyr397), without modifying total FAK expression. PF-573,228 decreased proliferation, decreased DNA synthesis, induced cell-cycle arrest in G2–M phases, and increased apoptosis in all cell lines. PF-573,228 also decreased motility in adherent cell lines. To make sure that these effects were not off-target, we then used a genetic method to inhibit FAK in NCI-H82 and NCI-H446, namely stable transduction with FAK shRNA and/or FAK-related nonkinase (FRNK), a splice variant lacking the N-terminal and kinase domains. Although FAK shRNA transduction decreased total and phospho-FAK (Tyr397) expression, it did not affect proliferation, DNA synthesis, or progression through cell cycle. However, restoration of FAK-targeting (FAT) domain (attached to focal adhesion complex where it inhibits pro-proliferative proteins such as Rac-1) by FRNK transduction inhibited proliferation, DNA synthesis, and induced apoptosis. Moreover, although FAK shRNA transduction increased active Rac1 level, FRNK reexpression in cells previously transduced with FAK shRNA decreased it. Therefore, FAK appears important in SCLC biology and targeting its kinase domain may have a therapeutic potential, while targeting its FAT domain should be avoided to prevent Rac1-mediated protumoral activity.

Tight junction complexes are involved in the establishment and maintenance of cell polarity and the regulation of signalling pathways, controlling biological processes such as cell differentiation and cell proliferation. MarvelD3 is a tight junction protein expressed in adult epithelial and endothelial cells. In Xenopus laevis, MarvelD3 morphants present differentiation defects of several ectodermal derivatives. In vitro experiments further revealed that MarvelD3 couples tight junctions to the MEKK1-JNK pathway to regulate cell behaviour and survival. In this work, we found that MarvelD3 is expressed from early developmental stages in the exocrine and endocrine compartments of the pancreas, as well as in endothelial cells of this organ. We thoroughly characterized MarvelD3 expression pattern in developing pancreas and evaluated its function by genetic ablation. Surprisingly, inactivation of MarvelD3 in mice did not alter development and differentiation of the pancreatic tissue. Moreover, tight junction formation and organization, cell polarization, and activity of the JNK-pathway were not impacted by the deletion of MarvelD3.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a devastating lung disease, mainly due to cigarette smoking, which represents the third cause of mortality worldwide. The mechanisms driving its epithelial salient features remain largely elusive. We aimed to evaluate the activation and the role of the canonical, β-catenin-dependant WNT pathway in the airway epithelium from COPD patients. METHODS: The WNT/β-catenin pathway was first assessed by WNT-targeted RNA sequencing of the air/liquid interface-reconstituted bronchial epithelium from COPD and control patients. Airway expression of total and active β-catenin was assessed in lung sections, as well as WNT components in laser-microdissected airway epithelium. Finally, we evaluated the role of WNT at the bronchial epithelial level by modulating the pathway in the reconstituted COPD epithelium. FINDINGS: We show that the WNT/β-catenin pathway is upregulated in the COPD airway epithelium as compared with that of non-smokers and control smokers, in targeted RNA-sequencing of in vitro reconstituted airway epithelium, and in situ in lung tissue and laser-microdissected epithelium. Extrinsic activation of this pathway in COPD-derived airway epithelium inhibited epithelial differentiation, polarity and barrier function, and induced TGF-β-related epithelial-to-mesenchymal transition (EMT). Conversely, canonical WNT inhibition increased ciliated cell numbers, epithelial polarity and barrier function, whilst inhibiting EMT, thus reversing COPD features. INTERPRETATION: In conclusion, the aberrant reactivation of the canonical WNT pathway in the adult airway epithelium recapitulates the diseased phenotype observed in COPD patients, suggesting that this pathway or its downstream effectors could represent a future therapeutic target. FUNDING: This study was supported by the Fondation Mont-Godinne, the FNRS and the WELBIO. ispartof: EBIOMEDICINE vol:61 ispartof: location:Netherlands status: published

Rationale: Asthma is associated with increased lung IgE production, but whether the secretory IgA system is affected in this disease remains unknown.Objectives: We explored mucosal IgA transport in...

Rationale: Research into pathways that drive COPD pathophysiology are key to unravel novel therapeutic targets. In contrast with the alveolar epithelium, the role of Wnt in the COPD bronchial epithelium (BE) remains unclear. Methods: We performed a targeted RNA sequencing (RNA-seq) of 92 preselected canonical Wnt-related genes in air/liquid interface-reconstituted BE from 47 patients (9 non-smoker controls, 10 smoker controls, 9 mild COPD, 10 moderate COPD and 9 very severe COPD). Quantification of active and total β-catenin was performed in immunostained BE. In addition, a pilot in vitro modulation experiment was carried out using CHIR99021 and XAV939 to activate or inhibit, respectively, the canonical Wnt pathway, to assess its role in broncho-epithelial differentiation. Results: RNA-seq data of Wnt genes was consistent with a global activation of the canonical Wnt pathway in COPD, as evidenced by the upregulation of PORCN, FZD7, CTNNB1, CSNK2A1&2, SOX4, TCF7L2, and MMP2&7 amongst others. This activation was more pronounced in very severe disease. Increased levels of both active and total β-catenin were observed in BE. In the pilot modulation experiment, CHIR99021 strongly inhibited epithelial differentiation for both goblet (SPDEF, MUC5AC) and ciliated cells (FOXJ1, DNAI1&2), as well as epithelial polarization (pIgR), while XAV939 promoted broncho-epithelial polarization. Conclusions: Canonical Wnt signalling is activated in the COPD bronchial epithelium, and could contribute to the COPD airway epithelial phenotype which will be further assessed through modulation experiments and in situ BE laser microdissection.

Inactivating mutations of the tumor suppressor Adenomatosis Polyposis Coli (APC), which are found in familial adenomatosis polyposis and in 80% of sporadic colorectal cancers (CRC), result in constitutive activation of the Wnt/&beta, catenin pathway and tumor development in the intestine. These mutations disconnect the Wnt/&beta, catenin pathway from its Wnt extracellular signal by inactivating the APC/GSK3-&beta, /axin destruction complex of &beta, catenin. This results in sustained nuclear accumulation of &beta, catenin, followed by &beta, catenin-dependent co-transcriptional activation of Wnt/&beta, catenin target genes. Thus, mechanisms acting downstream of APC, such as those controlling &beta, catenin stability and/or co-transcriptional activity, are attractive targets for CRC treatment. Protein Kinase C-&alpha, (PKC&alpha, ) phosphorylates the orphan receptor ROR&alpha, that then inhibits &beta, catenin co-transcriptional activity. PKC&alpha, also phosphorylates &beta, catenin, leading to its degradation by the proteasome. Here, using both in vitro (DLD-1 cells) and in vivo (C57BL/6J mice) PKC&alpha, knock-in models, we investigated whether enhancing PKC&alpha, function could be beneficial in CRC treatment. We found that PKC&alpha, is infrequently mutated in CRC samples, and that inducing PKC&alpha, function is not deleterious for the normal intestinal epithelium. Conversely, di-terpene ester-induced PKC&alpha, activity triggers CRC cell death. Together, these data indicate that PKC&alpha, is a relevant drug target for CRC treatment.

Small cell lung cancer (SCLC) has a poor prognosis. Focal adhesion kinase (FAK) is a non–receptor tyrosine kinase regulating cell proliferation, survival, migration, and invasion, which is overexpressed and/or activated in several cancers, including SCLC. We wanted to determine whether FAK contributes to SCLC aggressive behavior. We first evaluated the effect of FAK small-molecule inhibitor PF-573,228 in NCI-H82, NCI-H146, NCI-H196, and NCI-H446 SCLC cell lines. PF-573,228 (0.1–5 μmol/L) inhibited FAK activity by decreasing phospho-FAK (Tyr397), without modifying total FAK expression. PF-573,228 decreased proliferation, decreased DNA synthesis, induced cell-cycle arrest in G2–M phases, and increased apoptosis in all cell lines. PF-573,228 also decreased motility in adherent cell lines. To make sure that these effects were not off-target, we then used a genetic method to inhibit FAK in NCI-H82 and NCI-H446, namely stable transduction with FAK shRNA and/or FAK-related nonkinase (FRNK), a splice variant lacking the N-terminal and kinase domains. Although FAK shRNA transduction decreased total and phospho-FAK (Tyr397) expression, it did not affect proliferation, DNA synthesis, or progression through cell cycle. However, restoration of FAK-targeting (FAT) domain (attached to focal adhesion complex where it inhibits pro-proliferative proteins such as Rac-1) by FRNK transduction inhibited proliferation, DNA synthesis, and induced apoptosis. Moreover, although FAK shRNA transduction increased active Rac1 level, FRNK reexpression in cells previously transduced with FAK shRNA decreased it. Therefore, FAK appears important in SCLC biology and targeting its kinase domain may have a therapeutic potential, while targeting its FAT domain should be avoided to prevent Rac1-mediated protumoral activity.

International audience; Variations of protein kinase C (PKC) expression greatly influence the proliferation-to-differentiation transition (PDT) of intestinal epithelial cells and might have an important impact on intestinal tumorigenesis. We demonstrate here that the expression of PKCalpha in proliferating intestinal epithelial cells is repressed both in vitro and in vivo by the SOX9 transcription factor. This repression does not require DNA binding of the SOX9 high-mobility group (HMG) domain but is mediated through a new mechanism of SOX9 action requiring the central and highly conserved region of SOXE members. Because SOX9 expression is itself upregulated by Wnt-APC signaling in intestinal epithelial cells, the present study points out this transcription factor as a molecular link between the Wnt-APC pathway and PKCalpha. These results provide a potential explanation for the decrease of PKCalpha expression in colorectal cancers with constitutive activation of the Wnt-APC pathway.

Resume Les cellules tumorales presentent des variations du contenu de proteines pro- ou anti-tumorales qui leur procurent un avantage selectif de croissance par rapport aux cellules normales dont elles derivent. Le controle de ces taux proteiques s'effectue aux trois niveaux, ADN, ARNm et proteine, et est conditionne par la structure de chacun de ces trois acteurs pour la mise en œuvre des mecanismes moleculaires impliques dans le controle de la synthese, de la maturation et de la stabilite de l'ARNm et de la proteine elle-meme. Nous abordons ici les evenements principaux pouvant conduire a une deregulation de ces mecanismes. Pour citer cet article : S. Dupasquier, C. Quittau-Prevostel, C. R. Biologies 332 (2009).

Background: Chronic airway diseases like asthma and chronic obstructive pulmonary disease (COPD) are associated with abnormal mucosal responses to inhaled materials. In COPD, while immunoglobulin (Ig)A synthesis is up-regulated, expression of pIgR/SC (polymeric immunoglobulin receptor/secretory component) is markedly decreased, presumably resulting in impaired defense mechanisms against pathogens. Objectives: We explored IgA production and transport in human severe asthma and its potential regulation by the Th2/IL-13 pathway. Methods: Bronchial biopsies and in vitro-reconstituted bronchial epithelium from these biopsies, re-differentiated upon air-liquid interface (ALI-HBEC), were assayed for pIgR expression and regulation by IL-13. Results: We identified a downregulation of IgA1 and IgA2 mRNA synthesis in biopsies from severe asthma vs controls (p=0.002 for IgA1 and p=0.034 for IgA2). A downregulation of pIgR protein (but not mRNA) was also observed. IL-13 stimulation of ALI-HBEC induced, besides eotaxin-3 and periostin, a downregulation of SC release while pIgR mRNA levels were not affected, further suggesting post-transcriptional regulation of pIgR by IL-13. Conclusion: Altogether, this study shows impaired lung IgA responses in severe asthma and identifies IL-13 as potential mechanism, suggesting that targeting this cytokine could restore frontline IgA-mediated lung defence in chronic Th2-mediated airway disease.

MarvelD3 recruits MEKK1 to tight junctions, which down-regulates JNK signaling and is essential for maintaining the integrity of tight junctions and restricting cell migration and proliferation., MarvelD3 is a transmembrane component of tight junctions, but there is little evidence for a direct involvement in the junctional permeability barrier. Tight junctions also regulate signaling mechanisms that guide cell proliferation; however, the transmembrane components that link the junction to such signaling pathways are not well understood. In this paper, we show that MarvelD3 is a dynamic junctional regulator of the MEKK1–c-Jun NH2-terminal kinase (JNK) pathway. Loss of MarvelD3 expression in differentiating Caco-2 cells resulted in increased cell migration and proliferation, whereas reexpression in a metastatic tumor cell line inhibited migration, proliferation, and in vivo tumor formation. Expression levels of MarvelD3 inversely correlated with JNK activity, as MarvelD3 recruited MEKK1 to junctions, leading to down-regulation of JNK phosphorylation and inhibition of JNK-regulated transcriptional mechanisms. Interplay between MarvelD3 internalization and JNK activation tuned activation of MEKK1 during osmotic stress, leading to junction dissociation and cell death in MarvelD3-depleted cells. MarvelD3 thus couples tight junctions to the MEKK1–JNK pathway to regulate cell behavior and survival.

Background YBX3/ZONAB/CSDA is an epithelial-specific transcription factor acting in the density-based switch between proliferation and differentiation. Our laboratory reported overexpression of YBX3 in clear cell renal cell arcinoma (ccRCC), as part of a wide study of YBX3 regulation in vitro and in vivo. The preliminary data was limited to 5 cases, of which only 3 could be compared to paired normal tissue, and beta-Actin was used as sole reference to normalize gene expression. We thus decided to re-evaluate YBX3 expression by real-time-PCR in a larger panel of ccRCC samples, and their paired healthy tissue, with special attention on experimental biases such as inter-individual variations, primer specificity, and reference gene for normalization. Results Gene expression was measured by RT-qPCR in 16 ccRCC samples, each compared to corresponding healthy tissue to minimize inter-individual variations. Eight potential housekeeping genes were evaluated for expression level and stability among the 16-paired samples. Among tested housekeeping genes, PPIA and RPS13, especially in combination, proved best suitable to normalize gene expression in ccRCC tissues as compared to classical reference genes such as beta-Actin, GAPDH, 18S or B2M. Using this pair as reference, YBX3 expression level among a collection of 16 ccRCC tumors was not significantly increased as compared to normal adjacent tissues. However, stratification according to Fuhrman grade disclosed higher YBX3 expression levels in low-grade tumors and lower in high-grade tumors. Immunoperoxidase confirmed homogeneous nuclear staining for YBX3 in low-grade but revealed nuclear heterogeneity in high-grade tumors. Conclusions This paper underlines that special attention to reference gene products in the design of real-time PCR analysis of tumoral tissue is crucial to avoid misleading conclusions. Furthermore, we found that global YBX3/ZONAB/CSDA mRNA expression level may be considered within a “signature” of RCC grading.

Inherited and acquired changes in pre-mRNA processing have significant roles in human diseases, especially cancer. Characterization of aberrantly spliced mRNAs may thus contribute to understand malignant transformation. We recently reported an anti-oncogenic potential for the SOX9 transcription factor in the colon. For instance, the Sox9 gene knock out in the mouse intestine results in an excess of proliferation with appearance of hyperplasia. SOX9 is expressed in colon cancer cells but its endogenous activity is weak. We looked for SOX9 variants that may impair SOX9 activity in colon cancer cells and we discovered MiniSOX9, a truncated version of SOX9 devoid of transactivation domain as a result of retention of the second intron. A significant overexpression of MiniSOX9 mRNA in human tumor samples compared with their matched normal tissues was observed by real-time reverse transcriptase-PCR. Immunohistochemistry revealed that MiniSOX9 is expressed at high levels in human colon cancer samples whereas it is undetectable in the surrounding healthy tissues. Finally, we discovered that MiniSOX9 behaves as a SOX9 inhibitor, inhibits protein kinase Cα promoter activity and stimulates the canonical Wnt pathway. This potential oncogenic activity of the SOX9 locus gives new insights on its role in colon cancer.

Tumor cells exhibit significant variations in the rate of pro- or anti-tumoral proteins that provide them a selective advantage of growth over normal cells. The control of these rates occurs at the three DNA, RNA and protein levels, and is determined by the structure of each of these three actors for the implementation of the molecular mechanisms involved in the control of the synthesis, maturation and stability of the mRNA and the protein itself. We give here an overview of the main events that can lead to a disruption of these mechanisms.

N-Myc oncogene amplification is a frequent event in neuroblastoma and is strongly correlated with advanced disease stage and treatment failure. Similarly to c-Myc oncogenic activation, N-Myc deregulation promotes both cell proliferation and p53-dependent apoptosis by sensitizing cells to a variety of insults. Intriguingly, p53 mutations are uncommon in neuroblastomas, strongly suggesting that an alternative cooperating event circumvents this safeguard against oncogene-driven neoplasia. By performing a pangenomic cDNA microarray analysis, we demonstrate that human Twist is constantly overexpressed in N-Myc-amplified neuroblastomas. H-Twist overexpression is responsible for the inhibition of the ARF/p53 pathway involved in the Myc-dependent apoptotic response. This oncogenic cooperation of two key regulators of embryogenesis causes cell transformation and malignant outgrowth.