Nous remercions le SF 4206 ICORE (Université de Caen) pour l&#39;utilisation de la facilité de cytométrie. JC reçu des bourses post-doctorales du Conseil de Radioprotection d&#39;EDF et le Conseil Régional de Basse-Normandie. Ces données font partie des projets financés par la Ligue Nationale contre le Cancer - Comités de l&#39;Orne et du Calvados.

1. Préparation de C12FDG, bafilomycine A1 et de la culture cellulaire <ol><li> Dissoudre la poudre C 12 FDG dans le diméthylsulfoxyde (DMSO) à une concentration finale de 20 mM. Aliquote et conserver à -20 ° C. DMSO doit être utilisé avec des conditions de sécurité appropriées. </li><li> Dissoudre la poudre bafilomycine A1 dans le DMSO à une concentration finale de 0,1 mM. Aliquote et conserver à - 20 ° C. Bafilomycine doit être utilisé avec des conditions de sécurité appropriées. </li><li> Cultiver RPMI ligne 8226 de la cellule, ou d&#39;autres lignées de cellules adhérentes ou non, dans un milieu contenant 10% de sérum de veau fœtal et 1% d&#39;antibiotiques, à 37 ° C, 5% de CO 2. Estimer le nombre de cellules nécessaires pour l&#39;expérience. Afin d&#39;enregistrer un nombre suffisant d&#39;événements au cours de l&#39;analyse de cytométrie en flux, 5 x 10 5 cellules sont nécessaires. Pour déterminer le pourcentage de cellules sénescentes, trois échantillons de cellules sont nécessaires: échantillon non étiqueté, les cellules non traitées colorées avec C 12 FDG, les cellules traitées colorées avecC 12 FDG. </li><li> Seed les cellules 24 heures effectue avant l&#39;expérience afin que les cellules sont en phase logarithmique de la courbe de la prolifération cellulaire. </li></ol> 2. Induction de la sénescence <ol><li> Induire la sénescence des cellules cancéreuses par l&#39;ajout d&#39;un médicament chimiothérapeutique. la concentration du médicament et de la durée du traitement doivent être adaptés au type cellulaire testé. Commencer avec un traitement de 48 heures à la concentration finale de 50 nM de doxorubicine pour une concentration de cellules à environ 10 6 cellules / ml. Ne pas oublier d&#39;inclure échantillon non traité (témoin négatif). </li></ol> 3. Bafilomycine traitement A1 <ol><li> Vérifier la viabilité cellulaire de cellules de mélange avec du bleu trypan (v / v), en tant que médicament chimiothérapeutique utilisé dans l&#39;étape précédente pourrait conduire à l&#39;apoptose des cellules. Verser dans une chambre Malassez et compter le nombre de cellules bleues (cellules mortes) et des globules blancs (cellules vivantes). Si le pourcentage de viabilité est inférieur à 70%, les cellules mortes pourraient être removed l&#39;aide d&#39;un kit approprié pour s&#39;assurer que les cellules mortes ne sera pas biaiser l&#39;analyse ultérieure. </li><li> Retirez les milieux de culture et les remplacer par un milieu de culture frais préchauffé. Traiter les cellules avec une concentration finale de 100 nM de la bafilomycine A1. Bafilomycine A1 est utilisée pour neutraliser le pH acide des lysosomes. Incuber 1 heure à 37 ° C, 5% de CO 2. </li></ol> 4. C 12 FDG coloration <ol><li> Dissoudre C 12 FDG dans préchauffé milieu de culture frais à une concentration finale de 2 mM. </li><li> Ajouter le composé de cellules à une concentration finale de 33 uM et incuber 2 heures à 37 ° C, 5% de CO 2. Si l&#39;utilisation de cellules non-adhérentes, centrifuger les cellules à 300 g pendant 5 min à 4 ° C (la vitesse peut être ajustée au type de cellule utilisée), laver 2x avec PBS. Reprendre le culot cellulaire dans 500 pi de PBS froid. Si vous utilisez des cellules adhérentes, retirez le support et laver 2x avec PBS. Récolter les cellules adhérentes à l&#39;aide d&#39;une solution de trypsine et la centrifugeusecellules à 300 g pendant 5 min à 4 ° C (la vitesse peut être ajustée au type de cellule utilisée). Reprendre le culot cellulaire dans 500 pi de PBS froid. Dans les deux cas, la concentration cellulaire devrait être d&#39;environ 10 6 cellules / ml. </li><li> Effectuez une co-immuno-marquage pour mieux caractériser la population des cellules sénescentes. </li></ol> 5. L&#39;analyse de cytométrie en flux <ol><li> Calibrer le cytomètre en flux à l&#39;aide des billes de contrôle recommandées par le fabricant du cytomètre en flux. Pour toutes les mesures, au moins 10 4 événements doivent être enregistrés. </li><li> Exécutez le premier échantillon contenant des cellules non marquées. Préparer un graphique à deux paramètres affichage Channel Forward Scatter (FSC) par rapport à canal latéral Scatter (SSC). Réglez les tubes photomultiplicateurs (PMT) et de définir une zone d&#39;intérêt à l&#39;exclusion des cellules mortes et les débris cellulaires qui auraient pu apparaître au cours de la préparation des échantillons. Porte de cette région d&#39;intérêt dans un histogramme à un paramètre affichage FL1 sur l&#39;échelle logarithmiquede l&#39;axe des x et le nombre d&#39;événements dans l&#39;axe des y. Le nombre total d&#39;événements représente le nombre de cellules analysées. Régler le PMT afin que les cellules non marquées apparaissent dans la première décennie sur l&#39;échelle logarithmique de l&#39;axe des x. Déterminer l&#39;auto-fluorescence des cellules si nécessaire. </li><li> Exécutez le second échantillon contenant des cellules non traitées. D&#39;un paramètre histogramme affichant FL1 (fluorescence de C 12 FDG), placez le curseur après la population faiblement marqué. Ce seuil va permettre la discrimination entre les cellules non-sénescentes (cellules faiblement marquées) et les cellules sénescentes (cellules brillamment marqués). </li><li> Exécutez le troisième échantillon contenant des cellules traitées. Cellules brillamment marqué, c&#39;est à dire les cellules sénescentes apparaissent au-dessus du seuil déterminé à l&#39;étape précédente. Évaluer le pourcentage de cellules sénescentes en divisant le nombre d&#39;événements lumineux par le nombre total d&#39;événements. Si nécessaire, l&#39;activité de la β-galactosidase peut également être estimée en utilisant la fluorescence moyenneintensité. </li></ol>

<ol>
	<li>Hayflick, L., Moorhead, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+serial+cultivation+of+human+diploid+cell+strains.">The serial cultivation of human diploid cell strains.</a> Experimental Cell Research. 25, 585-621 (1961).</li><li>Campisi, J., d'Adda di Fagagna, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+senescence:+when+bad+things+happen+to+good+cells.">Cellular senescence: when bad things happen to good cells.</a> Nature Review Molecular Cell Biology. 8 (9), 729-740 (2007).</li><li>Shay, J. W., Roninson, I. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hallmarks+of+senescence+in+carcinogenesis+and+cancer+therapy.">Hallmarks of senescence in carcinogenesis and cancer therapy.</a> Oncogene. 23 (16), 2919-2933 (2004).</li><li>Bartkova, J., Rezaei, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oncogene-induced+senescence+is+part+of+the+tumorigenesis+barrier+imposed+by+DNA+damage+checkpoints.">Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints.</a> Nature. 444 (7119), 633-637 (2006).</li><li>Takacova, S., Slany, R., Bartkova, J., Stranecky, V., Dolezel, P., Luzna, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+damage+response+and+inflammatory+signaling+limit+the+MLL-ENL-induced+leukemogenesis+in+vivo.">DNA damage response and inflammatory signaling limit the MLL-ENL-induced leukemogenesis in vivo.</a> Cancer Cell. 21, 517-531 (2012).</li><li>Krtolica, A., Parrinello, S., Lockett, S., Desprez, P. Y., Campisi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Senescent+fibroblasts+promote+epithelial+cell+growth+and+tumorigenesis:+a+link+between+cancer+and+aging.">Senescent fibroblasts promote epithelial cell growth and tumorigenesis: a link between cancer and aging.</a> Proceedings of the National Academy of Sciences. 98, 12072-12077 (2001).</li><li>Coppe, J. P., Patil, C. K., Rodier, F., Sun, Y., Munoz, D. P., Goldstein, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Senescence-associated+secretory+phenotypes+reveal+cell-nonautonomous+functions+of+oncogenic+RAS+and+the+p53+tumor+suppressor.">Senescence-associated secretory phenotypes reveal cell-nonautonomous functions of oncogenic RAS and the p53 tumor suppressor.</a> PLoS Biology. 6, 2853-2868 (2008).</li><li>Roninson, I. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+cell+senescence+in+cancer+treatment.">Tumor cell senescence in cancer treatment.</a> Cancer Research. 63 (11), 2705-2715 (2003).</li><li>Dimri, G. P., Lee, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+biomarker+that+identifies+senescent+human+cells+in+culture+and+in+aging+skin+in+vivo.">A biomarker that identifies senescent human cells in culture and in aging skin in vivo.</a> Proceedings of the National Academy of Sciences. 92 (20), 9363-937 (1995).</li><li>Kurz, D. J., Decary, S., Hong, Y., Erusalimsky, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Senescence-associated+(beta)-galactosidase+reflects+an+increase+in+lysosomal+mass+during+replicative+ageing+of+human+endothelial+cells.">Senescence-associated (beta)-galactosidase reflects an increase in lysosomal mass during replicative ageing of human endothelial cells.</a> Journal of Cell Science. 113, 3613-3622 (2000).</li><li>Debacq-Chainiaux, F., Erusalimsky, J. D., Campisi, J., Toussaint, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protocols+to+detect+senescence-associated+beta-galactosidase+(SA-betagal)+activity,+a+biomarker+of+senescent+cells+in+culture+and+in+vivo.">Protocols to detect senescence-associated beta-galactosidase (SA-betagal) activity, a biomarker of senescent cells in culture and in vivo.</a> Nature Protocols. 4 (12), 1798-1806 (2009).</li><li>Cahu, J., Bustany, S., Sola, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Senescence-associated+secretory+phenotype+favors+the+emergence+of+cancer+stem-like+cells.">Senescence-associated secretory phenotype favors the emergence of cancer stem-like cells.</a> Cell Death and Disease. Dec 20, 3-e446 (2012).</li></ol>

Aucun conflit d&#39;intérêt déclaré.

Nous avons présenté ici une méthode cytométrie en flux offre de quantifier la sénescence cellulaire dans les cellules cancéreuses vivantes. Cette méthode est basée sur l&#39;utilisation du composé perméable de la membrane, la C 12 FDG, et peut donc être utilisé dans tous les types de cellules et après divers traitements aussi longtemps que le composé est absorbé par les cellules. Après l&#39;absorption cellulaire, la C 12 FDG est hydrolysé par la β-galactosidase, enrichi en lysoso...

Depuis le début des années soixante et sa découverte par Hayflick et Moorhead, sénescence reste une curiosité cellulaire 1. Les cellules humaines ne sont pas indéfiniment prolifèrent et, par la sénescence, Hayflick et Moorhead a inventé le processus cellulaire de vieillissement. Sénescence est un arrêt du cycle cellulaire stable dans laquelle les cellules restent métaboliquement active, par opposition à la mort cellulaire. À ce jour, quatre mécanismes cellulaires ont été montré pour induire la sénescence: le raccourcissement des télomères, des dommages de l&#39;ADN, la chromatine perturbation, et une expression anormale d&#39;oncogènes mitogènes 2. Cela signifie que non seulement les cellules normales mais également les cellules cancéreuses sont capables de subir la sénescence 3. En fait, les cellules cancéreuses subissent sénescence ont été présentés à constituer un obstacle à la progression tumorale 4-5. Cependant, plusieurs rapports ont souligné que, dans certaines circonstances, la sénescence cellulaire peut également favoriser la malignité 6-7. L&#39;étude de la sénescence du cancer cells est en passe de devenir un besoin en recherche sur le cancer tels qu&#39;ils sont actuellement utilisés médicaments chimiothérapeutiques peuvent conduire à la sénescence des cellules cancéreuses non seulement in vitro mais aussi in vivo 8. Le dosage de maître pour étudier la présence de cellules sénescentes est le test β-galactosidase à pH acide. Ce test histochimique reflète l&#39;augmentation de la biogenèse des lysosomes se produisant dans la plupart des cellules sénescentes. Brièvement, exogène X-gal, appliqué à des cellules, est clivé par β-galactosidase enrichi dans les lysosomes des cellules sénescentes, donnant lieu à une couleur bleue 9. Les cellules sénescentes bleus peuvent ensuite être quantifiés sous un microscope en champ clair. Bien que très populaire, le dosage de β-galactosidase présente des inconvénients majeurs. En premier lieu, ce test est réalisé sur des cellules fixées. Deuxièmement, il est temps car elle implique de quantifier le degré de sénescence en comptant un nombre significativement plus élevé de cellules sénescentes sous un microscope. Troisièmement, cet essain&#39;est pas aussi sensible que la discrimination entre les cellules sénescentes et non sénescentes repose entièrement sur l&#39;observateur. Nous discutons ici, un test basé sur la cytométrie rapide et sensible inexploité pour évaluer la présence de cellules sénescentes en direct. Ce dosage est basé sur l&#39;hydrolyse de la molécule de la membrane perméable, la 5-dodecanoylaminofluorescein di-β-D-galactopyranoside (C 12 FDG), par β-galactosidase enrichie en cellules sénescentes. Après hydrolyse et une excitation laser, le C 12 FDG émet une fluorescence verte et peut donc être détecté par cytométrie de flux 10, 11. La détection de cellules sénescentes par cytométrie en flux offre le grand avantage d&#39;être rapide et sensible. En outre, la détection de cellules sénescentes par cytométrie de flux peut être couplé avec la détection d&#39;autres marqueurs cellulaires. Ce test peut être utilisé pour détecter les cellules sénescentes sein d&#39;une population de cellules cancéreuses traitées avec la chimiothérapie et peut être régulièrement missur des coupes de tissus, après dissociation cellulaire, dans la clinique.

<table border="1">
		<tbody>
		 <tr>
			<td>Name of the Reagent</td>
			<td>Company</td>
			<td>Catalogue Number</td>
			<td>Comments</td>
		 </tr>
		 <tr>
			<td>5-dodecanoylaminofluorescein di-&beta;-D-galactopyranoside </td>
			<td>Invitrogen</td>
			<td>D-2893</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Dimethyl sulfoxide </td>
			<td>Sigma</td>
			<td>D2650</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Bafilomycin A1</td>
			<td>Sigma</td>
			<td>B1793</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Doxorubicin</td>
			<td>Sandoz</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Trypan blue</td>
			<td>Sigma</td>
			<td>T8154</td>
			<td></td>
		 </tr>
		 <tr>
			<td>RPMI 1640 cell culture medium</td>
			<td>Lonza</td>
			<td>BE12-702</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Fetal calf serum</td>
			<td>PAA Laboratories GmBH</td>
			<td>A15 101</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Antibiotics</td>
			<td>Gibco</td>
			<td>5290-018</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gallios flow cytometer</td>
			<td>Beckman Coulter</td>
			<td>A94291</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

a sensitive method to quantify senescent cancer cells

Les cellules humaines ne sont pas indéfiniment prolifèrent. Dès indices externes et / ou intrinsèque, les cellules peuvent mourir ou entrer un arrêt du cycle cellulaire stable appelé sénescence. Plusieurs mécanismes cellulaires tels que le raccourcissement des télomères et une expression anormale d&#39;oncogènes mitogènes, ont été montré pour causer la sénescence. La sénescence n&#39;est pas limitée aux cellules normales, les cellules cancéreuses ont également été signalés à vieillir. médicaments chimiothérapeutiques ont été montré pour induire la sénescence dans les cellules cancéreuses. Cependant, il reste controversée que la sénescence empêche ou favorise la tumorigenèse. Comme il pourrait éventuellement être spécifique au patient, une méthode rapide et sensible pour évaluer la sénescence des cellules du cancer sera bientôt nécessaire. À cette fin, le test β-galactosidase standard, la méthode actuellement utilisée, présente des inconvénients majeurs: il est temps et n&#39;est pas sensible. Nous vous proposons ici un test basé sur la cytométrie flux d&#39;étudier la sénescence sur live cellules. Ce test présente l&#39;avantage d&#39;être rapide, sensible et peut être couplé à l&#39;immuno-marquage de différents marqueurs cellulaires.

Myélome multiple, un cancer hématologique a été utilisé pour évaluer la sénescence induite par une procédure chimiothérapeutique. Pour ce faire, une lignée de cellules de MM disponibles dans le commerce (RPMI 8226) a été traitée pendant 2 jours avec la doxorubicine, un médicament chimiothérapeutique. Les cellules ont ensuite été soumis à un traitement bafilomycine A1 et encore incubées avec C 12 FDG. Les cellules ont été analysées par cytométrie de flux. Figure 1 illust...

Watch this Scientific Journal Video about A Sensitive Method to Quantify Senescent Cancer Cells at JoVE.com

A Sensitive Method to Quantify Senescent Cancer Cells

Que la sénescence empêche ou favorise la tumorigenèse reste controversée. Comme les médicaments chimiothérapeutiques peuvent induire des cellules cancéreuses à vieillir, est essentiel à étudier la sénescence de proposer de nouvelles thérapies. Cependant, le test β-galactosidase standard et largement utilisé présente des inconvénients majeurs. Nous vous proposons ici un test basé sur la cytométrie flux rapide et sensible pour quantifier la sénescence.

Une méthode sensible pour quantifier les cellules sénescentes du cancer

Human cells do not indefinitely proliferate. Upon external and/or intrinsic  cues, cells might die or enter a stable cell cycle arrest called senescence. ...

a-sensitive-method-to-quantify-senescent-cancer-cells

Research

JoVE Journal

Medicine

20.5K vues.  Université de Caen Basse-Normandie. Que la sénescence empêche ou favorise la tumorigenèse reste controversée. Comme les médicaments chimiothérapeutiques peuvent induire des cellules cancéreuses à vieillir, est essentiel à étudier la sénescence de proposer de nouvelles thérapies. Cependant, le test β-galactosidase standard et largement utilisé présente des inconvénients majeurs. Nous vous proposons ici un test basé sur la cytométrie flux rapide et sensible pour quantifier la sénescence.

Vidéo: A Sensitive Method to Quantify Senescent Cancer Cells

A Method for Murine Islet Isolation and Subcapsular Kidney Transplantation

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize their blood glucose levels, islet transplantation has been proposed to be a potential treatment for type 1 diabetes 1,2. More recently, advances in human islet transplantation have further strengthened this view 1,3. However, two major limitations prevent islet transplantation from being a widespread clinical reality: (a) the requirement for large numbers of islets per patient, which severely reduces the number of potential recipients, and (b) the need for heavy immunosuppression, which significantly affects the pediatric population of patients due to their vulnerability to long-term immunosuppression. Strategies that can overcome these limitations have the potential to enhance the therapeutic utility of islet transplantation.
Islet transplantation under the mouse kidney capsule is a widely accepted model to investigate various strategies to improve islet transplantation. This experiment requires the isolation of high quality islets and implantation of islets to the diabetic recipients. Both procedures require surgical steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol. We also briefly discuss different transplantation models: syngeneic, allogeneic, syngeneic autoimmune, and allogeneic autoimmune.

Transplantation of isolated islets has been proposed to be a potential treatment for type 1 diabetes. Here we describe a method to isolate islets from mouse pancreata and transplant them to the subcapsular space of the kidney.

Une méthode pour isoler l&#39;îlot murin et transplantation rénale sous-capsulaires

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize ...

Recherche

Médecine

Corneal Confocal Microscopy: A Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies

The accurate quantification of peripheral neuropathy is important to define at risk patients, anticipate deterioration, and assess new therapies. Conventional methods assess neurological deficits and electrophysiology and quantitative sensory testing quantifies functional alterations to detect neuropathy. However, the earliest damage appears to be to the small fibres and yet these tests primarily assess large fibre dysfunction and have a limited ability to demonstrate regeneration and repair. The only techniques which allow a direct examination of unmyelinated nerve fibre damage and repair are sural nerve biopsy with electron microscopy and skin-punch biopsy. However, both are invasive procedures and require lengthy laboratory procedures and considerable expertise. Corneal Confocal microscopy is a non-invasive clinical technique which provides in-vivo imaging of corneal nerve fibres. We have demonstrated early nerve damage, which precedes loss of intraepidermal nerve fibres in skin biopsies together with stratification of neuropathic severity and repair following pancreas transplantation in diabetic patients. We have also demonstrated nerve damage in idiopathic small fibre neuropathy and Fabry's disease.

Corneal Confocal microscopy is a non-invasive clinical technique which may be used to quantify C fibre damage to diagnose and stratify patients with increasing neuropathic severity.

Microscopie confocale cornéenne: A Novel technique non invasive pour quantifier Fibre petites pathologie dans les neuropathies périphériques

The accurate quantification of peripheral neuropathy is important to define at risk patients, anticipate deterioration, and assess new therapies. ...

A Real-time Electrical Impedance Based Technique to Measure Invasion of Endothelial Cell Monolayer by Cancer Cells

Metastatic dissemination of malignant cells requires degradation of basement membrane, attachment of tumor cells to vascular endothelium, retraction of endothelial junctions and finally invasion and migration of tumor cells through the endothelial layer to enter the bloodstream as a means of transport to distant sites in the host1-3. Once in the circulatory system, cancer cells adhere to capillary walls and extravasate to the surrounding tissue to form metastatic tumors4,5. The various components of tumor cell-endothelial cell interaction can be replicated in vitro by challenging a monolayer of human umbilical vein endothelial cells (HUVEC) with cancer cells. Studies performed with electron and phase-contrast microscopy suggest that the in vitro sequence of events fairly represent the in vivo metastatic process6. Here, we describe an electrical-impedance based technique that monitors and quantifies in real-time the invasion of endothelial cells by malignant tumor cells.
Giaever and Keese first described a technique for measuring fluctuations in impedance when a population of cells grow on the surface of electrodes7,8. The xCELLigence instrument, manufactured by Roche, utilizes a similar technique to measure changes in electrical impedance as cells attach and spread in a culture dish covered with a gold microelectrode array that covers approximately 80% of the area on the bottom of a well. As cells attach and spread on the electrode surface, it leads to an increase in electrical impedance9-12. The impedance is displayed as a dimensionless parameter termed cell-index, which is directly proportional to the total area of tissue-culture well that is covered by cells. Hence, the cell-index can be used to monitor cell adhesion, spreading, morphology and cell density.
The invasion assay described in this article is based on changes in electrical impedance at the electrode/cell interphase, as a population of malignant cells invade through a HUVEC monolayer (Figure 1). The disruption of endothelial junctions, retraction of endothelial monolayer and replacement by tumor cells lead to large changes in impedance. These changes directly correlate with the invasive capacity of tumor cells, i.e., invasion by highly aggressive cells lead to large changes in cell impedance and vice versa. This technique provides a two-fold advantage over existing methods of measuring invasion, such as boyden chamber and matrigel assays: 1) the endothelial cell-tumor cell interaction more closely mimics the in vivo process, and 2) the data is obtained in real-time and is more easily quantifiable, as opposed to end-point analysis for other methods.

This article describes an in vitro technique for monitoring cancer cells invading through a monolayer of endothelial cells. The data is acquired in real-time as a function of changes in impedance on the surface of electrodes at the well bottom.

Une technique basée Impédance électrique en temps réel pour mesurer Invasion de monocouche de cellules endothéliales par les cellules cancéreuses

Metastatic dissemination of malignant cells requires degradation of basement membrane, attachment of tumor cells to vascular endothelium, retraction of ...

A Simple Guide Screw Method for Intracranial Xenograft Studies in Mice

The grafting of human tumor cells into the brain of immunosuppressed mice is an established method for the study of brain cancers including glioblastoma (glioma) and medulloblastoma. The widely used stereotactic approach only allows for the injection of a single animal at a time, is labor intensive and requires highly specialized equipment. The guide screw method, initially developed by Lal et al.,1 was developed to eliminate cumbersome stereotactic procedures. We now describe a modified guide screw approach that is rapid and exceptionally safe; both of which are critical ethical considerations. Notably, our procedure now incorporates an infusion pump that allows up to 10 animals to be simultaneously injected with tumor cells.
To demonstrate the utility of this procedure, we established human U87MG glioma cells as intracranial xenografts in mice, which were then treated with AMG102; a fully human antibody directed to HGF/scatter factor currently undergoing clinical evaluation2-5. Systemic injection of AMG102 significantly prolonged the survival of all mice with intracranial U87MG xenografts and resulted in a number of complete cures. 
This study demonstrates that the guide screw method is an inexpensive, highly reproducible approach for establishing intracranial xenografts. Furthermore, it provides a relevant physiological model for validating novel therapeutic strategies for the treatment of brain cancers.

In order to evaluate novel therapeutic paradigms for the treatment of glioma, physiological relevant models are essential. We utilize an implantable guide screw procedure for establishment of intracranial xenograft models that is more rapid and safer than stereotactic approaches.

Une méthode simple guide de vis pour intracrânienne études de xénogreffe chez la souris

The grafting of human tumor cells into the brain of immunosuppressed mice is an established method for the study of brain cancers including glioblastoma ...

Three Dimensional Cultures: A Tool To Study Normal Acinar Architecture vs. Malignant Transformation Of Breast Cells

Invasive breast carcinomas are a group of malignant epithelial tumors characterized by the invasion of adjacent tissues and propensity to metastasize. The interplay of signals between cancer cells and their microenvironment exerts a powerful influence on breast cancer growth and biological behavior1. However, most of these signals from the extracellular matrix are lost or their relevance is understudied when cells are grown in two dimensional culture (2D) as a monolayer. In recent years, three dimensional (3D) culture on a reconstituted basement membrane has emerged as a method of choice to recapitulate the tissue architecture of benign and malignant breast cells. Cells grown in 3D retain the important cues from the extracellular matrix and provide a physiologically relevant ex&#160;vivo system2,3. Of note, there is growing evidence suggesting that cells behave differently when grown in 3D as compared to 2D4. 3D culture can be effectively used as a means to differentiate the malignant phenotype from the benign breast phenotype and for underpinning the cellular and molecular signaling involved3. One of the distinguishing characteristics of benign epithelial cells is that they are polarized so that the apical cytoplasm is towards the lumen and the basal cytoplasm rests on the basement membrane. This apico-basal polarity is lost in invasive breast carcinomas, which are characterized by cellular disorganization and formation of anastomosing and branching tubules that haphazardly infiltrates the surrounding stroma. These histopathological differences between benign gland and invasive carcinoma can be reproduced in 3D6,7. Using the appropriate read-outs like the quantitation of single round acinar structures, or differential expression of validated molecular markers for cell proliferation, polarity and apoptosis in combination with other molecular and cell biology techniques, 3D culture can provide an important tool to better understand the cellular changes during malignant transformation and for delineating the responsible signaling.

Three dimensional culture of mammary epithelial cells on a reconstituted basement membrane is a useful method to recapitulate the in vivo architecture of the benign breast, and to differentiate the malignant phenotype from the benign breast phenotype. Importantly, this system can be applied to study invasive carcinomas in other tissues.

Trois Cultures dimensionnelles: un outil pour étudier l&#39;architecture normale Acinaire vs transformation maligne des cellules mammaires

Invasive breast carcinomas are a group of malignant epithelial tumors characterized by the invasion of adjacent tissues and propensity to metastasize. The ...

Isolation of Cancer Stem Cells From Human Prostate Cancer Samples

The cancer stem cell (CSC) model has been considerably revisited over the last two decades. During this time CSCs have been identified and directly isolated from human tissues and serially propagated in immunodeficient mice, typically through antibody labeling of subpopulations of cells and fractionation by flow cytometry. However, the unique clinical features of prostate cancer have considerably limited the study of prostate CSCs from fresh human tumor samples. We recently reported the isolation of prostate CSCs directly from human tissues by virtue of their HLA class I (HLAI)-negative phenotype. Prostate cancer cells are harvested from surgical specimens and mechanically dissociated. A cell suspension is generated and labeled with fluorescently conjugated HLAI and stromal antibodies. Subpopulations of HLAI-negative cells are finally isolated using a flow cytometer. The principal limitation of this protocol is the frequently microscopic and multifocal nature of primary cancer in prostatectomy specimens. Nonetheless, isolated live prostate CSCs are suitable for molecular characterization and functional validation by transplantation in immunodeficient mice.

The isolation of cancer stem cells (CSCs) directly from human tissues is requisite for their biological characterization. This manuscript describes a methodology for the isolation of prostate CSCs from human tissues, while also providing tips on troubleshooting difficult steps.

Isolement de cellules souches du cancer à partir d&#39;échantillons cancer de la prostate humaine

The cancer stem cell (CSC) model has been considerably revisited over the last two decades. During this time CSCs have been identified and directly ...

Method for Obtaining Primary Ovarian Cancer Cells From Solid Specimens

Reliable tools for investigating ovarian cancer initiation and progression are urgently needed. While the use of ovarian cancer cell lines remains a valuable tool for understanding ovarian cancer, their use has many limitations. These include the lack of heterogeneity and the plethora of genetic alterations associated with extended in vitro passaging.&#160;Here we describe a method that allows for rapid establishment of primary ovarian cancer cells form solid clinical specimens collected at the time of surgery. The method consists of subjecting clinical specimens to enzymatic digestion for 30 min. The isolated cell suspension is allowed to grow and can be used for downstream application including drug screening. The advantage of primary ovarian cancer cell lines over established ovarian cancer cell lines is that they are representative of the original specific clinical specimens they are derived from and can be derived from different sites whether primary or metastatic ovarian cancer.

This study describes a detailed method for isolation and characterization of primary ovarian cancer cells from solid clinical specimens. Ovarian cancer clinical specimens are subjected to enzymatic digestion to obtain viable, fibroblast-free epithelial ovarian cancer (EOC) cells highly suitable for downstream applications.

Méthode pour l&#39;obtention de cellules cancéreuses ovariennes primaires à partir d&#39;échantillons solides

Reliable tools for investigating ovarian cancer initiation and progression are urgently needed. While the use of ovarian cancer cell lines remains a ...

An In Vitro Dormancy Model of Estrogen-sensitive Breast Cancer in the Bone Marrow: A Tool for Molecular Mechanism Studies and Hypothesis Generation

The study of breast cancer dormancy in the bone marrow is an exceptionally difficult undertaking due to the complexity of the interactions of dormant cells with their microenvironment, their rarity and the overwhelming excess of hematopoietic cells. Towards this end, we developed an in vitro 2D clonogenic model of dormancy of estrogen-sensitive breast cancer cells in the bone marrow. The model consists of a few key elements necessary for dormancy. These include 1) the use of estrogen sensitive breast cancer cells, which are the type likely to remain dormant for extended periods, 2) incubation of cells at clonogenic density, where the structural interaction of each cell is primarily with the substratum, 3) fibronectin, a key structural element of the marrow and 4) FGF-2, a growth factor abundantly synthesized by bone marrow stromal cells and heavily deposited in the extracellular matrix. Cells incubated with FGF-2 form dormant clones after 6 days, which consist of 12 or less cells that have a distinct flat appearance, are significantly larger and more spread out than growing cells and have large cytoplasm to nucleus ratios. In contrast, cells incubated without FGF-2 form primarily growing colonies consisting of >30 relatively small cells. Perturbations of the system with antibodies, inhibitors, peptides or nucleic acids on day 3 after incubation can significantly affect various phenotypic and molecular aspects of the dormant cells at 6 days and can be used to assess the roles of membrane-localized or intracellular molecules, factors or signaling pathways on the dormant state or survival of dormant cells. While recognizing the in vitro nature of the assay, it can function as a highly useful tool to glean significant information about the molecular mechanisms necessary for establishment and survival of dormant cells. This data can be used to generate hypotheses to be tested in vivo models.

An In Vitro Dormancy Model of Estrogen-sensitive Breast Cancer in the Bone Marrow: A Tool for Molecular Mechanism Studies and Hypothesis Generation

We developed an in vitro model of dormancy in the bone marrow for estrogen-sensitive breast cancer cells. The goal of this protocol is to demonstrate use of the model for the study of the molecular and cellular biology of dormancy and for generation of hypotheses for subsequent testing in vivo.

Une<em&gt; In Vitro</em&gt; Modèle dormance du cancer du sein sensible aux œstrogènes dans la moelle osseuse: un outil pour les études de mécanisme moléculaire et Hypothèse Generation

The study of breast cancer dormancy in the bone marrow is an exceptionally difficult undertaking due to the complexity of the interactions of dormant ...

Utilization of the Soft Agar Colony Formation Assay to Identify Inhibitors of Tumorigenicity in Breast Cancer Cells

Given the inherent difficulties in investigating the mechanisms of tumor progression in vivo, cell-based assays such as the soft agar colony formation assay (hereafter called soft agar assay), which measures the ability of cells to proliferate in semi-solid matrices, remain a hallmark of cancer research. A key advantage of this technique over conventional 2D monolayer or 3D spheroid cell culture assays is the close mimicry of the 3D cellular environment to that seen in vivo. Importantly, the soft agar assay also provides an ideal tool to rigorously test the effects of novel compounds or treatment conditions on cell proliferation and migration. Additionally, this assay enables the quantitative assessment of cell transformation potential within the context of genetic perturbations. We recently identified peptidylarginine deiminase 2 (PADI2) as a potential breast cancer biomarker and therapeutic target. Here we highlight the utility of the soft agar assay for preclinical anti-cancer studies by testing the effects of the PADI inhibitor, BB-Cl-amidine (BB-CLA), on the tumorigenicity of human ductal carcinoma in situ (MCF10DCIS) cells.

Here, we document the use of the soft agar colony formation assay to test the effects of a peptidylarginine deiminase (PADI) enzyme inhibitor, BB-Cl-amidine, on breast cancer tumorigenicity in vitro.

L&#39;utilisation de l&#39;essai de formation souple Agar colonie à identifier des inhibiteurs de Tumorigénicité dans les cellules cancéreuses du sein

Given the inherent difficulties in investigating the mechanisms of tumor progression in vivo, cell-based assays such as the soft agar colony formation ...

Studying Pancreatic Cancer Stem Cell Characteristics for Developing New Treatment Strategies

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor initiation, metastasis and resistance to radio- and chemotherapy. Here we describe a specific methodology for culturing primary human pancreatic CSCs as tumor spheres in anchorage-independent conditions. Cells are grown in serum-free, non-adherent conditions in order to enrich for CSCs while their more differentiated progenies do not survive and proliferate during the initial phase following seeding of single cells. This assay can be used to estimate the percentage of CSCs present in a population of tumor cells. Both size (which can range from 35 to 250 micrometers) and number of tumor spheres formed represents CSC activity harbored in either bulk populations of cultured cancer cells or freshly harvested and digested tumors 1,2. Using this assay, we recently found that metformin selectively ablates pancreatic CSCs; a finding that was subsequently further corroborated by demonstrating diminished expression of pluripotency-associated genes/surface markers and reduced in vivo tumorigenicity of metformin-treated cells. As the final step for preclinical development we treated mice bearing established tumors with metformin and found significantly prolonged survival. Clinical studies testing the use of metformin in patients with PDAC are currently underway (e.g., NCT01210911, NCT01167738, and NCT01488552). Mechanistically, we found that metformin induces a fatal energy crisis in CSCs by enhancing reactive oxygen species (ROS) production and reducing mitochondrial transmembrane potential. In contrast, non-CSCs were not eliminated by metformin treatment, but rather underwent reversible cell cycle arrest. Therefore, our study serves as a successful example for the potential of in vitro sphere formation as a screening tool to identify compounds that potentially target CSCs, but this technique will require further in vitro and in vivo validation to eliminate false discoveries.

Pancreatic cancer stem cells (CSCs) can be expanded in vitro using the anchorage-independent sphere culture technique, which represents a powerful tool to study CSC biology and can serve as the first step to develop novel CSC-targeting therapies. Here the methodology for expanding, analyzing and targeting of pancreatic CSCs is provided.