Search

Multiple myeloma (MM) cell lines and primary tumor cells are addicted to the MYC oncoprotein for survival. Little is known, however, about how MYC expression is upregulated in MM cells. The mucin 1 C-terminal subunit (MUC1-C) is an oncogenic transmembrane protein that is aberrantly expressed in MM cell lines and primary tumor samples. The present studies demonstrate that targeting MUC1-C with silencing by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 editing or with the GO-203 inhibitor is associated with downregulation of MYC messenger RNA and protein. The results show that MUC1-C occupies the MYC promoter and thereby activates the MYC gene by a β-catenin/transcription factor 4 (TCF4)-mediated mechanism. In this way, MUC1-C (1) increases β-catenin occupancy on the MYC promoter, (2) forms a complex with β-catenin and TCF4, and, in turn, (3) drives MYC transcription. Analysis of MM cells using quantitative real-time reverse transcription polymerase chain reaction arrays further demonstrated that silencing MUC1-C is associated with downregulation of MYC target genes, including CCND2, hTERT, and GCLC Analysis of microarray data sets further demonstrated that MUC1 levels positively correlate with MYC expression in MM progression and in primary cells from over 800 MM patients. These findings collectively provide convincing evidence that MUC1-C drives MYC expression in MM.

Dysregulation of MYC expression is a hallmark of cancer, but the development of agents that target MYC has remained challenging. The oncogenic MUC1-C transmembrane protein is, like MYC, aberrantly expressed in diverse human cancers. The present studies demonstrate that MUC1-C induces MYC expression in KRAS mutant non–small cell lung cancer (NSCLC) cells, an effect that can be suppressed by targeting MUC1-C via shRNA silencing, CRISPR editing, or pharmacologic inhibition with GO-203. MUC1-C activated the WNT/β-catenin (CTNNB1) pathway and promoted occupancy of MUC1-C/β-catenin/TCF4 complexes on the MYC promoter. MUC1-C also promoted the recruitment of the p300 histone acetylase (EP300) and, in turn, induced histone H3 acetylation and activation of MYC gene transcription. We also show that targeting MUC1-C decreased the expression of key MYC target genes essential for the growth and survival of NSCLC cells, such as TERT and CDK4. Based on these results, we found that the combination of GO-203 and the BET bromodomain inhibitor JQ1, which targets MYC transcription, synergistically suppressed MYC expression and cell survival in vitro as well as tumor xenograft growth. Furthermore, MUC1 expression significantly correlated with that of MYC and its target genes in human KRAS mutant NSCLC tumors. Taken together, these findings suggest a therapeutic approach for targeting MYC-dependent cancers and provide the framework for the ongoing clinical studies addressing the efficacy of MUC1-C inhibition in solid tumors. Cancer Res; 76(6); 1538–48. ©2016 AACR.

Introduction: MUC1, an O-glycoprotein membrane-bound mucin, is overexpressed in renal clear-cell carcinomas (CRCC) with correlation to two major prognostic factors, Tumor-Node-Metastasis stage and nuclear Fürhman grade. Previously, we have shown that (i) MUC1 was significantly overexpressed in metastatic CRCC vs non-metastatic CRCC and (ii) MUC1 is a target gene of HIF-1 transcription factor which is a part of the hypoxia pathway, the main renal carcinogenetic pathway. Furthermore, CRCC is highly resistant to common systemic chemotherapies. Material and method: To better understand the roles of MUC1 in CRCC, we used two renal cell lines expressing MUC1 (786-O cells) or not (ACHN cells). 786-O cells were stably transfected with shRNA targeting MUC1 while ACHN cells with full-length MUC1. Proliferation, drug resistance, migration and invasion properties were studied in vitro in the different cellular clones using MTS cell proliferation assay, wound healing assay and Boyden chambers coated with Matrigel, respectively. Signaling pathways were screened by proteome profiler and western blot. Results and discussion: We showed that MUC1 expression was associated with increased invasion and migration properties of renal carcinomatous cells and a decrease of cell-cell interactions. MUC1 overexpressing cells (i) expressed higher levels of anti-apoptotic factors and MDR genes involved in chemoresistance processes and (ii) were more resistant to chemotherapeutic drugs. Conclusion: Our results show that MUC1 plays a role in biological properties of renal cancer cells suggesting important function for this mucin in tumour progression and chemo-resistance. Our data confirm its potential as a therapeutic target in this type of cancer. Citation Format: Kelly Gaudelot, Viviane Gnemmi, Audrey Bouillez, Jean-Baptiste Gibier, Mélanie Fanchon, Justine Woszczyk, Brigitte Hémon, Isabelle Van Seuningen, Sébastien Aubert, Michael Perrais. The MUC1 membrane-bound mucin increases tumor cell properties and chemoresistance in renal clear cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5047.

MUC1 is overexpressed in human carcinomas. The transcription factor SNAIL can activate epithelial-mesenchymal transition (EMT) in cancer cells. In this study, in renal carcinoma, we demonstrate that (i) MUC1 and SNAIL were overexpressed in human sarcomatoid carcinomas, (ii) SNAIL increased indirectly MUC1 expression, (iii) MUC1 overexpression induced EMT, (iv) MUC1 C-terminal domain (MUC1-C) and β-catenin increased SNAIL transcriptional activity by interaction with its promoter and (v) blocking MUC1-C nuclear localization decreased Wnt/β-catenin signaling pathway activation and SNAIL expression. Altogether, our findings demonstrate that MUC1 is an actor in EMT and appears as a new therapeutic target.

Renal cell carcinoma corresponds to 5% of all adult malignancies and originates from renal tubules. The main histologic subtype is represented by clear renal cell carcinoma. Ninety percent of cRCC present a biallelic inactivation of the von Hippel Lindau (VHL) tumor suppressor gene resulting in constitutive activation of hypoxia signaling pathway via the Hypoxia Inducible Factor (HIF) -1 transcription factor that contributes to the physiology of tumours. cRCC is typically highly resistant to conventional systemic therapies. MUC1 is a membrane-anchored mucin and its cytoplasmic tail (CT) can interact with many signaling pathways and act as a co-transcription factor to activate genes involved in tumor progression and metastasis. Previous studies have shown that MUC1 is diffusely overexpressed in cRCC and MUC1 overexpression has been found to be associated with metastatic disease and a worse prognosis.MUC1 is overexpressed in renal cell carcinoma with correlation to prognosis and has been implicated in the hypoxic pathway, the main renal carcinogenetic pathway. In this context, we assessed the effects of MUC1 overexpression on renal cancer cells properties. Using shRNA strategy and/or different MUC1 constructs, we found that MUC1-extracellular domain and MUC1 CT are both involved in increase of migration, cell viability, resistance to anoikis and to decrease of cell aggregation in cancer cells. We also showed that MUC1 is involved in cRCC chemoresistance by inducing chemoresistance genes expression like ABCG2 and GSTO2. Invasiveness depends only on MUC1 CT. Then, by using siRNA strategy and/or pharmacological inhibitors or peptides, we showed that sheddases ADAM10, ADAM17 and gamma-secretase are necessary for MUC1 C-terminal subunit (MUC1-C) nuclear location and in increase of invasion property. Finally, MUC1 overexpression increases ADAM10/17 protein expression suggesting a positive regulatory loop. In conclusion, we report that MUC1 acts in renal cancer progression and MUC1-C nuclear localization is driving invasiveness of renal cancer cells through a sheddase/gamma secretase dependent pathway. MUC1 appears as a therapeutic target by blocking MUC1 cleavage or nuclear translocation by using pharmacological approach and peptide strategies., Le carcinome rénal représente 5% des tumeurs de l’adulte et se développe au niveau des tubules rénaux. Le sous-type histologique majeur des cancers du rein est le carcinome rénal à cellules claires (cRCC). 90% des cRCC présentent une inactivation biallélique du gène suppresseur de tumeur de Von Hippel Lindau (VHL) induisant une activation constitutive de la voie de l’hypoxie via le facteur de transcription HIF1-α (Hypoxia Inducible Factor) qui contribue à la physiologie des tumeurs. Les cRCC sont des tumeurs à la fois radio- et chimiorésistantes, rendant la prise en charge thérapeutique des patients très difficile.Nos recherches consistaient en l’étude des rôles de la mucine membranaire MUC1, dont la queue cytoplasmique (MUC1 CT) peut interagir avec différentes voies de signalisation et agir en tant que co-activateur transcriptionnel de nombreux gènes impliqués dans la progression tumorale et la diffusion métastatique. Des travaux antérieurs réalisés au laboratoire montraient que la surexpression de MUC1 observée dans les cRCC était associée au statut métastatique des patients et marquait un mauvais pronostic. Cette surexpression de MUC1 est également impliquée dans la voie de l’hypoxie, voie majeure de la carcinogenèse rénale. Le premier objectif de l’étude était donc de déterminer les effets de la surexpression de MUC1 sur les propriétés des cellules de cRCC. Nous montrons ainsi que le domaine extracellulaire de MUC1 ainsi que sa partie cytoplasmique sont impliqués dans l’augmentation des capacités migratoires et de la viabilité des cellules cancéreuses rénales et qu’elle leur confère une résistance à l’anoïkis, programme de mort cellulaire déclenché lorsque la cellule perd ses contacts avec les cellules voisines ou avec la matrice extra-cellulaire et diminuent les propriétés d’agrégation des cellules tumorales. Nous montrons également que MUC1 est impliquée dans la chimiorésistance des cRCC en induisant l’expression de genes de chimiorésistance comme ABCG2 et GSTO2. Nous montrons par ailleurs que les propriétés invasives des cellules de cRCC sont exclusivement liées à MUC1 CT. Le deuxième objectif de l’étude était d’identifier les mécanismes moléculaires à l’origine du clivage de MUC1 CT. En utilisant différentes stratégies (siARN, inhibiteurs pharmacologiques et peptides), nous montrons pour la première fois que deux sheddases, ADAM10 et ADAM17 et la gamma secrétase sont nécessaires au clivage de MUC1 C, permettant ainsi sa délocalisation nucléaire et l’augmentation des propriétés invasives des cellules de cRCC. Enfin, nous montrons que la surexpression de MUC1 augmente l’expression protéique d’ADAM10/17, suggérant une boucle de régulation positive existant en conditions pathologiques.En conclusion, notre étude souligne le rôle de MUC1 dans la progression tumorale rénale et montre que la localisation nucléaire de MUC1-C est à l’origine de l’acquisition d’un phénotype invasif et chimiorésistant via l’action des sheddases ADAM10/17 et de la gamma secrétase. MUC1 apparait alors comme une cible thérapeutique potentielle intéressante dans la prise en charge des cRCC.

International audience; MUC1 is a membrane-anchored mucin and its cytoplasmic tail (CT) can interact with many signaling pathways and act as a co-transcription factor to activate genes involved in tumor progression and metastasis. MUC1 is overexpressed in renal cell carcinoma with correlation to prognosis and has been implicated in the hypoxic pathway, the main renal carcinogenetic pathway. In this context, we assessed the effects of MUC1 overexpression on renal cancer cells properties. Using shRNA strategy and/or different MUC1 constructs, we found that MUC1-extracellular domain and MUC1-CT are involved in increase of migration, cell viability, resistance to anoikis and in decrease of cell aggregation in cancer cells. Invasiveness depends only on MUC1-CT. Then, by using siRNA strategy and/or pharmacological inhibitors or peptides, we showed that sheddases ADAM10, ADAM17 and gamma-secretase are necessary for MUC1 C-terminal subunit (MUC1-C) nuclear location and in increase of invasion property. Finally, MUC1 overexpression increases ADAM10/17 protein expression suggesting a positive regulatory loop. In conclusion, we report that MUC1 acts in renal cancer progression and MUC1-C nuclear localization drives invasiveness of cancer cells through a sheddase/gamma secretase dependent pathway. MUC1 appears as a therapeutic target by blocking MUC1 cleavage or nuclear translocation by using pharmacological approach and peptide strategies.

Renal proximal tubular epithelial cells play a central role in renal physiology and are among the cell types most sensitive to ischemia and xenobiotic nephrotoxicity. In order to investigate the molecular and cellular mechanisms underlying the pathophysiology of kidney injuries, a stable and well-characterized primary culture model of proximal tubular cells is required. An existing model of proximal tubular cells is hampered by the cellular heterogeneity of kidney; a method based on cell sorting for specific markers must therefore be developed. In this study, we present a primary culture model based on the mechanical and enzymatic dissociation of healthy tissue obtained from nephrectomy specimens. Renal epithelial cells were sorted using co-labeling for CD10 and CD13, two renal proximal tubular epithelial markers, by flow cytometry. Their purity, phenotypic stability and functional properties were evaluated over several passages. Our results demonstrate that CD10/CD13 double-positive cells constitute a pure, functional and stable proximal tubular epithelial cell population that displays proximal tubule markers and epithelial characteristics over the long term, whereas cells positive for either CD10 or CD13 alone appear to be heterogeneous. In conclusion, this study describes a method for establishing a robust renal proximal tubular epithelial cell model suitable for further experimentation.

In response to the widespread use of β-lactam antibiotics bacteria have evolved drug resistance mechanisms that include the production of resistant Penicillin Binding Proteins (PBPs). Boronic acids are potent β-lactamase inhibitors and have been shown to display some specificity for soluble transpeptidases and PBPs, but their potential as inhibitors of the latter enzymes is yet to be widely explored. Recently, a (2,6-dimethoxybenzamido)methylboronic acid was identified as being a potent inhibitor of Actinomadura sp. R39 transpeptidase (IC50: 1.3 μM). In this work, we synthesized and studied the potential of a number of acylaminomethylboronic acids as inhibitors of PBPs from different classes. Several derivatives inhibited PBPs of classes A, B and C from penicillin sensitive strains. The (2-nitrobenzamido)methylboronic acid was identified as a good inhibitor of a class A PBP (PBP1b from Streptococcus pneumoniae, IC50 = 26 μM), a class B PBP (PBP2xR6 from Streptococcus pneumoniae, IC50 = 138 μM) and a class C PBP (R39 from Actinomadura sp., IC50 = 0.6 μM). This work opens new avenues towards the development of molecules that inhibit PBPs, and eventually display bactericidal effects, on distinct bacterial species.

The National Ignition Facility at Lawrence Livermore National Laboratory will be a national center to study inertial confinement fusion and the physics of high energy and pressure. The $1.2 billion project consists of 192 laser beams which will direct more than 500 trillion watts towards a tiny target in a pulse only a billionth of a second long. The laser contains neodymium glass amplifiers which are pumped by xenon flashlamps. The flashlamps have silver reflectors to direct the light toward the glass laser slabs. Silver is ideal because of its high reflectance from 400 to 1000 nm wavelength which matches the neodymium absorption cross-section. In order to maintain the overall efficiency of the laser beams, there is an effort to prevent the corrosion of the silver reflectors by various means. One solution is the use of durable protected silver coatings which must survive 24,000 exposures to intense flashlamp light over a 30-year period while being exposed to small levels of atmospheric corrodants. One protected silver reflector has survived 20,717 flashlamp discharges so far in 100% Livermore atmosphere with no change in reflectance. This paper describes another protected silver reflector which is very durable.

MUC1, an O-glycoprotein membrane-bound mucin, is overexpressed in clear-cell carcinomas (cRCC) with correlation to two prognostic factors, tumor-node metastasis stage and nuclear Fürhman grade. Previously (Aubert et al, Cancer Res 2009), we have shown that MUC1 was significantly overexpressed in metastatic cRCC vs non-metastatic cRCC and MUC1 is a target gene of HIF-1 transcription factor which is a part of the hypoxia pathway, the main renal carcinogenetic pathway. To better understand the roles of MUC1 in cRCC, we used two renal cell lines expressing MUC1 (Caki-2) or not (ACHN cells). Caki-2 cells were stably transfected with shRNA targeting MUC1 and ACHN cells with an expressing vector containing MUC1 cDNA. Flow cytometry assay and confocal microscopy showed a homogenous membrane expression of MUC1 but also in the nucleus. In vitro studies underlined MUC1 role in the invasion, migration and anchorage-independent growth. In contrast, MUC1 had no role in proliferation and clonogenicity. Cellular agreggation test showed that MUC1 expression is associated with a decrease of cell-cell interactions. Phospho-JNK and phospho-p38 levels were higher in MUC1 expressing cells. Transcriptomic analysis results performed on 44K Agilent Microarrays suggest that MUC1 is a candidate in chemoresistance. Subcutaneous xenograft will be also performed. Our results show that MUC1 plays a role in biological properties of renal cancer cells suggesting the important function for this mucin in tumor progression and confirms its potential as a therapeutic target in this type of cancer. 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 2737. doi:10.1158/1538-7445.AM2011-2737

Accumulating data suggest that epithelial mesenchymal transition (EMT) is involved in cancer progression. Sarcomatoid carcinoma represents a high-grade transformation and an EMT-like pattern. Up to 8% of conventional renal cells cancers (cRCC) present with sarcomatoid carcinoma component that portends a worse prognosis. MUC1, a membrane-bound glycoprotein is known to be over-expressed in cRCC with correlation to prognosis. Indeed, we showed that MUC1 overexpression is correlated with a metastatic phenotype using tissue microarray sampling 27 cRCC of same TNM stage. Also, we demonstrated in a series of 15 RCC with sarcomatoid component, the loss of epithelial markers and the acquisition of mesenchymal markers compared to conventional carcinomatous areas. MUC1 was significantly overexpressed along with Snai1, a major actor of EMT, in sarcomatoid component. So, we hypothesized that MUC1 could be regulated by Snai1. Bioinformatic analyses revealed two Snai1 E-boxes at -84/-72 on MUC1 promoter. Cotransfection studies of MUC1 promoter and Snai1 expression vectors in renal cells lines showed an induction of MUC1 transcriptional activity by luciferase assays. Mutagenesis site-directed of both Snai1 E-boxes in renal cells lines induced loss MUC1 transcriptional activity. By chromatin immunoprecipation assay and gel shift analysis we will demonstrate a direct interaction between Snai1 and MUC1 promoter. In conclusion, all these data revealed that MUC1, usually considered as an epithelial marker, is overexpressed during cancer linked EMT process with a direct regulation by Snai1 suggesting that MUC1 plays a role in renal cancer 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 5250. doi:10.1158/1538-7445.AM2011-5250

MUC1, an O-glycoprotein membrane-bound mucin, is overexpressed in renal clear-cell carcinomas (CRCC) with correlation to two major prognostic factors, Tumor-Node-Metastasis stage and nuclear Fürhman grade. Previously (Aubert et al., Cancer Res 2009), we have shown that (i) MUC1 was significantly overexpressed in metastatic CRCC vs non-metastatic CRCC and (ii) MUC1 is a target gene of HIF-1 transcription factor which is a part of the hypoxia pathway, the main renal carcinogenetic pathway. To better understand the roles of MUC1 in CRCC, we used two renal cell lines expressing MUC1 (Caki-2 cells) or not (ACHN cells). Caki-2 cells were stably transfected with shRNA targeting MUC1 and ACHN cells with an expressing vector containing MUC1 cDNA. Proliferation, migration and invasion properties were studied in vitro in the different cellular clones using Boyden chambers coated with Matrigel, wound healing assay and MTS cell proliferation assay, respectively. Our results showed that (i) MUC1 expression was associated with an increase of invasion and migration properties of renal carcinoma cells whereas no effect on proliferation and apoptotic rate was observed and (ii) levels of phospho-JNK were higher in MUC1 expressing cells. Results of (i) transcriptomic analysis on 44K Agilent microarrays, (ii) signaling pathway screening and (iii) subcutaneous xenografts will be presented. Our results show that MUC1 plays a role in biological properties of renal cancer cells suggesting important function for this mucin in tumour progression and confirms its potential as a therapeutic target in this type of cancer. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. 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 2457.

The syntheses and characterization of metal imidazole complexes showing activity against Trypanosoma cruzi, the causative agent of Chagas disease, are presented, RuCl2(CTZ)2 (2) and RuCl2(BTZ)2 (4) were prepared by reaction of RuCl2(NCCH3)4 (1) with the appropriate ligand (CTZ, clotrimazole = 1-[(2-chlorophenyl)diphenylmethyl]-1H-imidazole; BTZ = 1-[(2-bromophenyl)diphenylmethyl]-1H-imidazole) [Ru(bipy)(CTZ)2](PF6)2 (3) (bipy=2,2′-bipyridyl) was obtained by reaction of 2 with bipy and NH4PF6 in MeCN. Reaction of [RhCl(COD)]2 with CTZ yielded RhCl(COD)(CTZ) (5) (COD=1,5-cyclooctadiene), while AuCl1CTZ (6), K2[PtCl4(CTZ)2] (7) and [Cu(CTZ)2]PF6 (8) were obtained by interaction of CTZ with AuCl1·HCl, K2PtCl4 and [Cu(CH3CN)4]PF6, respectively. All the new complexes were characterized by NMR and other appropriate techniques, X-ray diffraction studies of 4·3H2O, 5 and 6 were also carried out. The structure of 4·3H2O consists of a distorted tetrahedral arrangement of two N atoms from the BTZ ligands and two Cl atoms around the Ru(II) ion; 4·3H2O crystallizes in the orthorhombic space group Puma (No. 62) with a=12.818(5), b=29.115(5), c=12.040(5) A , V=4493.2(8) A and Z=4. Complex 5 displayed a square planar structure typical for Rh(1) bound to N from CTZ, Cl, and the two CC bonds of COD; 5 crystallized in the triclinic space group (P(= l) (No. 2) with a=12.407(3), b=12.876(4), c=10.069(3) A , α=111.59(2)°, β=107.80(2)°, γ=103.28(2)°, V=1313.4(8) A 3 and Z=2. Complex 6 also displayed a square arrangement of N from CTZ, plus three Cl atoms around the Au(III) ion; 6 crystallized in the monoclinic space group P21/n (No. 14) with a=9.507(1), b=18.280(4), c=12.877(1) A , β=100.59(1)°, V=2199.7(5) A 3 and Z=4. All the new compounds were found to be active against in vitro cultures of Trypanosoma cruzi, following the trend 3 = 7