Improved retroviral suicide gene transfer in colon cancer cell lines after cell synchronization with methotrexate

<p>Abstract</p> <p>Background</p> <p>Cancer gene therapy by retroviral vectors is mainly limited by the level of transduction. Retroviral gene transfer requires target cell division. Cell synchronization, obtained by drugs inducing a reversible inhibition of DNA synthesis, could therefore be proposed to precondition target cells to retroviral gene transfer. We tested whether drug-mediated cell synchronization could enhance the transfer efficiency of a retroviral-mediated gene encoding herpes simplex virus thymidine kinase (HSV-<it>tk</it>) in two colon cancer cell lines, DHDK12 and HT29.</p> <p>Methods</p> <p>Synchronization was induced by methotrexate (MTX), aracytin (ara-C) or aphidicolin. Gene transfer efficiency was assessed by the level of HSV-TK expression. Transduced cells were driven by ganciclovir (GCV) towards apoptosis that was assessed using annexin V labeling by quantitative flow cytometry.</p> <p>Results</p> <p>DHDK12 and HT29 cells were synchronized in S phase with MTX but not ara-C or aphidicolin. In synchronized DHDK12 and HT29 cells, the HSV-TK transduction rates were 2 and 1.5-fold higher than those obtained in control cells, respectively. Furthermore, the rate of apoptosis was increased two-fold in MTX-treated DHDK12 cells after treatment with GCV.</p> <p>Conclusions</p> <p>Our findings indicate that MTX-mediated synchronization of target cells allowed a significant improvement of retroviral HSV-<it>tk </it>gene transfer, resulting in an increased cell apoptosis in response to GCV. Pharmacological control of cell cycle may thus be a useful strategy to optimize the efficiency of retroviral-mediated cancer gene therapy.</p

Rectal cancer with synchronous unresectable metastases: arguments for therapeutic choice

Environ 4 000 patients sont pris en charge chaque année en France pour un cancer du rectum avec des métastases synchrones jugées non résécables en réunion de concertation pluridisciplinaire (RCP). Il n’existe pas de consensus sur la stratégie thérapeutique à proposer et parmi les trois options possibles, les critères de choix restent relativement imprécis. – La chirurgie première est certes le meilleur traitement pour contrôler les symptômes rectaux mais elle n’a pas démontré qu’elle augmentait la survie et la résécabilité secondaire des métastases par rapport aux autres options et comporte un risque de résection incomplète, de complications pouvant retarder ou empêcher la chimiothérapie, de progression accélérée de la maladie métastatique et de mortalité comprise entre 1 et 5 %. – La radio-chimiothérapie première suivie d’une chirurgie permet le contrôle des symptômes rectaux mais retarde la chimiothérapie pour les métastases qui dominent le pronostic ; elle expose aux mêmes risques de complications que la chirurgie première. – La chimiothérapie première nous paraît intéressante en absence de complications locales sévères (occlusion, hémorragie) ; elle est potentiellement efficace sur les métastases à distance qui conditionnent le pronostic et sur la tumeur primitive qui répond souvent de manière similaire ; elle ne fige pas la stratégie et offre la possibilité de l’adapter à chaque évaluation selon la réponse, la tolérance et les possibilités de résection (tumeur primitive et métastases). Dans tous les cas, il est fondamental de discuter ces dossiers au cas par cas en RCP pour adapter la stratégie thérapeutique aux caractéristiques du patient, de la tumeur primitive et de l’extension métastatique, ainsi qu’à la réponse obtenue aux traitements proposés successivement.Rectal cancers with synchronous unresectable metastases are diagnosed in about 4 000 patients. There is yet no consensus on the therapeutic strategy for these cases which must be discussed during multidisciplinary meeting. Three options are available and arguments of choice remain relatively weak. – First-line resection of the primary rectal tumour is indeed the best treatment to control rectal symptoms but it does not seem to improve survival and secondary resectability of metastases when compared to other options; moreover incomplete resection or complications may delay chemotherapy, accelerate the metastastic process and mortality rate ranges from 1 to 5%. – First-line radio-chemotherapy followed by surgery allows for controlling rectal symptoms but delays chemotherapy for metastases dominating the prognosis; it exposes the patients to the same morbidity and mortality as first-line surgery. – First-line chemotherapy is the third valid option in the absence of major rectal symptoms (occlusion, haemorrhage); chemotherapy is potentially efficient on distant metastases bearing a high prognosis impact and on the primary rectal tumour, which often has a similar response. First-line chemotherapy allows for adapting the therapeutic strategy after each evaluation according to the tumour response, side effects and possibility of resection (primary rectal tumour and metastases). In all cases, medical records of such patients should be discussed during a multidisciplinary meeting to adapt the therapeutic strategy to the patient’s characteristics, primary rectal tumor, metastases staging and evolution

Matrix-comparative genomic hybridization from multicenter formalin-fixed paraffin-embedded colorectal cancer tissue blocks

<p>Abstract</p> <p>Background</p> <p>The identification of genomic signatures of colorectal cancer for risk stratification requires the study of large series of cancer patients with an extensive clinical follow-up. Multicentric clinical studies represent an ideal source of well documented archived material for this type of analyses.</p> <p>Methods</p> <p>To verify if this material is technically suitable to perform matrix-CGH, we performed a pilot study using macrodissected 29 formalin-fixed, paraffin-embedded tissue samples collected within the framework of the EORTC-GI/PETACC-2 trial for colorectal cancer. The scientific aim was to identify prognostic genomic signatures differentiating locally restricted (UICC stages II-III) from systemically advanced (UICC stage IV) colorectal tumours.</p> <p>Results</p> <p>The majority of archived tissue samples collected in the different centers was suitable to perform matrix-CGH. 5/7 advanced tumours displayed 13q-gain and 18q-loss. In locally restricted tumours, only 6/12 tumours showed a gain on 13q and 7/12 tumours showed a loss on 18q. Interphase-FISH and high-resolution array-mapping of the gain on 13q confirmed the validity of the array-data and narrowed the chromosomal interval containing potential oncogenes.</p> <p>Conclusion</p> <p>Archival, paraffin-embedded tissue samples collected in multicentric clinical trials are suitable for matrix-CGH analyses and allow the identification of prognostic signatures and aberrations harbouring potential new oncogenes.</p

Le foie bioartificiel interne

Le foie bioartificiel interne (FBAI), encore expérimental, peut représenter une alternative intéressante à la transplantation hépatique. Il a pour but de réaliser un foie auxiliaire transitoire, le temps d’obtenir la régénération du foie natif. Son principe repose sur la transplantation d’hépatocytes isolés immunoprotégés par macroencapsulation, à l’intérieur de l’organisme du receveur. Ces hépatocytes peuvent être allogéniques ou provenir d’animaux, et, dans ce cas, être préparés à la demande, sans recourir à des méthodes de conservation. Le péritoine est probablement le meilleur site d’accueil du FBAI. Dans le futur, le FBAI pourrait être proposé comme traitement de maladies métaboliques par déficit enzymatique ou de certaines insuffisances hépatiques aiguës ou chroniques avec encéphalopathie. Il pourrait être également un traitement transitoire en attente d’un greffon hépatique

Neoplastic progression of human colorectal cancer is associated with overexpression of the stromelysin-3 andBM-40/SPARC genes

International audienc