Development of new therapies for glioblastoma requires animal models that mimic the biological characteristics of human brain tumors. On the other hand, potential antitumoral effects of a new therapeutic strategy are often established by evaluation of tumor cells apoptosis. Caspases are key mediators in the regulation and execution of apoptosis. Caspase-9 is activated during the intrinsic pathway downstream of mitochondria while caspase-3 is an effector caspase that initiates degradation of the cell in the final stages of apoptosis. Bax is a pro-apoptotic member of the Bcl-2 family that play key roles in the regulation of intrinsic apoptotic signaling. In the present study we investigated the immunohistochemical distribution of caspase 3, 9 and Bax in intracranial U87 glioblastoma xenograft. Immunohistochemistry showed that the glioblastoma xenografts contain cells positive for caspase-3, caspase-9, and Bax.
In this study, we addressed the hypothesis that transcriptional suppression of erythroblastosis virus E26 oncogene homolog 1 (ETS-1) is an efficient therapeutic approach to pancreatic adenocarcinoma by investigating the effect of ETS-1 suppression in human pancreatic cancer cells. We accomplished this by using an adenoviral vector encoding only the DNA-binding domain of wild-type ETS-1 (ETS-1 dominant negative, ETS-1-DN). ETS-1-DN decreases ETS-1-binding by competing for its binding to DNA. Adenoviralmediated transfer of ETS-1-DN (adenoviral ETS-1-DN construct, AdETS-1-DN) into pancreatic tumor cell lines did not affect their proliferation rate in vitro but did significantly inhibit their in vivo growth in nude mice. Furthermore, to test the efficacy of ETS-1-DN in vivo, we injected the AdETS-1-DN into established human pancreatic adenocarcinomas grown in nude mice. This treatment significantly reduced tumor size as compared to saline injection, without any detectable side effects. Microvessel density in mouse xenografts displayed significantly lower values in tumors in which ETS-1 was downregulated. In addition, expression of the ETS-1-DN in the pancreatic cancer cells resulted in downregulation of urokinase-type plasminogen activator (u-PA) and metalloproteinase-1 (MMP-1) expression. Taken together, these data suggest that transcriptional inactivation of ETS-1 is able to significantly affect angiogenesis and growth of pancreatic cancer. This effect may be due in part to downregulation of MMP-1 and u-PA expression. Our results suggest that ETS-1-DN is a promising candidate for antiangiogenic gene therapy in pancreatic cancer.
Hematopoiesis is maintained by the activity of multipotent stem cells, which have the dual capacity to self‐renew and to differentiate into all of the blood cell lineages. The major challenge of stem cells based regenerative therapy is to expand ex vivo the primitive compartment to increase transplantable stem cells number. The present study was designed to evaluate several culture systems for in vitro maintenance of umbilical cord blood stem cells. The influences of different growth conditions such as stromal feeder layer, cytokines supplement and placental conditioned medium (PCM) have been evaluated over a relatively short period of time on CD34+ cell expansion and maintenance of clonogenic progenitors. When cells were expanded on feeder layer in the presence of added cytokines and PCM on average a 2.96‐fold increase of CD34+CD71‐ and a 3.13‐fold increase of CD34+HLA‐DR‐ was observed. The total number of colony forming cells (35±2.65) indicated also that the yield of clonogenic progenitors obtained with a combination of all factors was two folds higher than each of these factors alone and ten time above control (3.67± 2.52). In conclusion, the results of our study clearly show that the ex vivo expansion of hematopoietic progenitor cells obtained from human umbilical cord blood is dependent on controlled experimental conditions, which might be helpful when designing culture systems for clinical applications.
The role of Human Papillomaviruses (HPV) in laryngeal carcinomas has been studied with conflicting results. To evaluate the etiologic relationship between HPV infection and epithelial malignancy of the larynx we studied five laryngeal carcinoma cell lines obtained from patients undergoing surgery for laryngeal tumors. The paraffin embedded biopsy samples of the original tumor and different passages of the new established cell lines were investigated by PCR with consensus primers specific for HPV DNA. The findings indicate that HPV infection is associated with some larynx carcinomas. The positive association has been enhanced when a method of enrichment of epithelial cells from fresh tumor samples was used. All tumor cells enriched smears were positive for HPV DNA not only by PCR but also by in situ hybridization (ISH). Investigated by PCR, different passages of larynx tumor cell lines maintained expression of HPV DNA. At subsequent passages ISH gives constantly no signals suggesting a minimal amount of viral harbored sequences. In one cell line propagated more than 60 population doublings, the chromosomal frequency distribution shifted from modal number 46 at the 5th passage to 63 at the 60th passage. The mechanisms by which persistent HPV infection maintains continuous cell proliferation were discussed.
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