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CAR Expression (car + expression)
Selected AbstractsHDAC inhibitor valproic acid enhances tumor cell kill in adenovirus-HSVtk mediated suicide gene therapy in HNSCC xenograft mouse modelINTERNATIONAL JOURNAL OF CANCER, Issue 3 2010Vishal Kothari Abstract Safety, efficacy and enhanced transgene expression are the primary concerns while using any vector for gene therapy. One of the widely used vectors in clinical trials is adenovirus which provides a safe way to deliver the therapeutic gene. However, adenovirus has poor transduction efficiency in vivo since most tumor cells express low coxsackie and adenovirus receptors. Similarly transgene expression remains low, possibly because of the chromatization of adenoviral genome upon infection in eukaryotic cells, an effect mediated by histone deacetylases (HDACs). Using a recombinant adenovirus (Ad-HSVtk) carrying the herpes simplex thymidine kinase (HSVtk) and GFP genes we demonstrate that HDAC inhibitor valproic acid can bring about an increase in CAR expression on host cells and thereby enhanced Ad-HSVtk infectivity. It also resulted in an increase in transgene (HSVtk and GFP) expression. This, in turn, resulted in increased cell kill of HNSCC cells, following ganciclovir treatment in vitro as well as in vivo in a xenograft nude mouse model. [source] N -acetylcysteine augments adenovirus-mediated gene expression in human endothelial cells by enhancing transgene transcription and virus entryTHE JOURNAL OF GENE MEDICINE, Issue 1 2002L. Jornot Abstract Background It has previously been shown that oxidants reduce the efficiency of adenoviral transduction in human umbilical vein endothelial cells (HUVECs). In this study, the effect of the antioxidant N -acetylcysteine (NAC) in adenovirus-mediated gene transfer has been investigated. Methods HUVECs were pretreated or not with NAC, and infected with E1E3-deleted adenovirus (Ad) containing the LacZ gene expressed from the RSV-LTR promoter/enhancer in the presence and absence of NAC. Transgene expression was assessed at the protein level (histochemical staining, measurement of ,-Gal activity, and western blot), mRNA level (real-time RT-PCR) and gene level (nuclear run on) 24,h and 48,h after infection. Adenoviral DNA was quantitated by real-time PCR, and cell surface expression of Coxsackie/adenovirus receptors (CAR) was determined by FACS analysis. Results Pretreatment of cells with NAC prior to Ad infection enhanced ,-Gal activity by two-fold due to an increase in viral DNA, which was related to increased CAR expression. When NAC was present only during the post-infection period, a five-fold increase in ,-Gal activity and LacZ gene transcriptional activity was observed. When NAC was present during both the pretreatment and the post-infection period, ,-Gal activity was further enhanced, by 15-fold. Augmentation of ,-Gal activity was paralleled by an increase in ,-Gal protein and mRNA levels. NAC did not affect the half-life of LacZ mRNA. Conclusion Pretreatment with NAC prior to Ad infection enhances virus entry, while treatment with NAC post-infection increases transgene transcription. This strategy permits the use of lower adenoviral loads and thus might be helpful for gene therapy of vascular diseases. Copyright © 2001 John Wiley & Sons, Ltd. [source] Evaluation of coxsackievirus and adenovirus receptor expression in human benign and malignant thyroid lesionsAPMIS, Issue 3 2010CONSTANTINOS GIAGINIS Giaginis C, Zarros A, Alexandrou P, Klijanienko J, Delladetsima I, Theocharis S. Evaluation of coxsackievirus and adenovirus receptor expression in human benign and malignant thyroid lesions. APMIS 2010; 118: 210,21. Coxsackievirus and adenovirus receptor (CAR) expression on tumor cells is associated with sensitivity to adenoviral infection, being considered as a surrogate marker for monitoring and/or predicting adenovirus-mediated gene therapy. The aim of this study was to evaluate the clinical significance of CAR expression in human benign and malignant thyroid lesions. CAR protein expression was assessed immunohistochemically on paraffin-embedded thyroid tissues from 107 patients with benign and malignant lesions and was statistically analyzed in relation to histopathologic type; tumor size; lymph node metastasis; capsular, lymphatic and vessel invasion; as well as follicular cells' proliferative capacity. CAR immunoreactivity was characterized as negative/weak in 53 (49.53%), moderate in 31 (28.97%) and strong in 23 (21.50%) of 107 thyroid cases. CAR immunoreactivity was significantly increased in malignant compared with that in benign thyroid lesions (p = 0.00002). Both malignant and benign thyroid lesions with enhanced follicular cells' proliferative capacity showed significantly increased CAR immunoreactivity (p = 0.00027). In malignant thyroid lesions, enhanced CAR immunoreactivity was significantly associated with larger tumor size (p = 0.0067). The current data revealed that CAR immunoreactivity could be considered of diagnostic utility in thyroid neoplasia. Further research effort is warranted to delineate whether CAR could be considered clinically important for both diagnosis and future (gene) therapeutic applications in thyroid neoplasia. [source] Human parathyroid cell proliferation in response to calcium, NPS R-467, calcitriol and phosphateEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2001M-C. Roussanne It remains uncertain how calcium, phosphate and calcitriol regulate parathyroid cell growth. The present study was aimed at examining possible direct effects of these modulators and of the calcimimetic NPS R-467 on parathyroid cell growth in vitro. Cell proliferation was determined by [3H]thymidine incorporation and cell cycle antigen Ki 67 expression in a parathyroid cell culture model derived from uraemic patients. The effect of NPS R-467 on parathyroid hormone (PTH) secretion and intracellular [Ca2+]i response was also examined. Increasing the [Ca2+] in the medium from 0·5 to 1·7 mM increased DNA synthesis (P < 0·005) and the number of Ki 67-positive cells (P < 0·005). However, NPS R-467 (0·01,1 µM) inhibited 3[H]thymidine incorporation by 35% in the presence of 0·5 mM [Ca2+]e. Exposure of cells to Ca2+ or NPS R-467 led to a rapid increase of intracellular Ca2+, although the pattern of increase differed. Addition of calcitriol (10,10,10,7 M) to the culture medium suppressed [3H]thymidine incorporation dose-dependently. Finally, high levels of phosphate (3·5 mM) in the medium led to a significant (P < 0·05) increase in [3H]thymidine incorporation. The observed stimulatory effect of Ca2+ in the medium in vitro appears to be at variance with the inhibitory effect of calcimimetic NPS R-467 in vitro. In an attempt to solve these apparent discrepancies, and based on the notion of a reduced calcium-sensing receptor (CaR) expression in parathyroid tissues of uraemic patients, we hypothesize that Ca2+ may regulate parathyroid cell proliferation via two different pathways, with predominant growth inhibition in cases of high CaR expression or activation, but prevailing stimulation of proliferation in cases of low CaR expression. [source] | ||||||||||