Biomedical subjects

R N Georges

Publications and source records attributed to R N Georges.

7 recordsLinked to original sources

PubMed1994

Therapeutic effect of a retroviral wild-type p53 expression vector in an orthotopic lung cancer model.

BACKGROUND: Mutations in the p53 tumor suppressor gene (also known as TP53) are common in human lung cancers. The wild-type form of p53 is dominant over the mutant; thus, restoration of wild-type p53 function in lung cancer cells may suppress their growth as tumors. PURPOSE: We investigated the therapeutic efficacy of direct administration of a retroviral wild-type p53 (wt-p53) expression vector (LNp53B) in an orthotopic human lung cancer model in nu/nu mice. METHODS: Proliferation of H226Br cells was determined by cell counting after infection with LNp53B in vitro. Irradiated (350 cGy) female BALB/c nu/nu mice were inoculated intratracheally with 2 x 10(6) H226Br cells (whose p53 gene has a homozygous mutation at codon 254) and treated beginning 3 days later with an intratracheal instillation of LNp53B retroviral supernatant for 3 days. RESULTS: Infection with LNp53B inhibited proliferation of H226Br cells in vitro. Thirty days after tumor cell inoculation, 62%-80% of the control mice showed macroscopic tumors of the right main stem bronchus. LNp53B suppressed H226Br tumor formation in 62%-100% of mice, and the effect was abrogated by dilution of the retroviral supernatant with inactive vector. CONCLUSIONS: Direct administration of a retroviral vector expressing wt-p53 may inhibit local growth in vivo of human lung cancer cells with abnormal p53 expression. IMPLICATIONS: Development of gene-replacement treatment strategies based on the type of mutations found in target cancers is warranted and may lead to the development of new adjunctive therapies and gene-specific prevention strategies for lung cancer.

Animals↗

PubMed1994

High-efficiency gene transfer and high-level expression of wild-type p53 in human lung cancer cells mediated by recombinant adenovirus.

A replication-defective and helper-independent recombinant p53 adenovirus was generated. The virus, Ad5CMV-p53, carries an expression cassette that contains human cytomegalovirus E1 promoter, human wild-type p53 cDNA, and SV40 early polyadenylation signal. Four human non-small-cell lung cancer cell lines representing differences in p53 configuration were used to evaluate the Ad5CMV-p53 virus. In the H358 cell line, which has a homozygous deletion of p53, the p53 gene was transferred with 97% to 100% efficiency, as detected by immunohistochemical analysis, when the cells were infected with Ad5CMV-p53 at a multiplicity of infection of 30 to 50 plaque-forming units/cell. Western blots showed that the p53 protein was expressed at a high level. The protein expression peaked at day 3 after infection and lasted for at least 15 days. Growth of the Ad5CMV-p53 virus-infected H358 cells was inhibited 79%, whereas that of noninfected cells or the cells infected with the control virus was not inhibited. Growth of cell line H322, which has a point mutation in p53, was inhibited 72% by Ad5CMV-p53, while that of cell line H460 containing wild-type p53 was less affected (28% inhibition). Tests in nude mice demonstrated that tumorigenicity of the Ad5CMV-p53-treated H358 cells was greatly inhibited. In a mouse model of orthotopic human lung cancer, the tumorigenic H226Br cells, with a point mutation in p53, were inoculated intratracheally 3 days before the virus treatment. Intratracheal instillation of Ad5CMV-p53 prevented tumor formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviruses, Human↗

PubMed1993

Prevention of orthotopic human lung cancer growth by intratracheal instillation of a retroviral antisense K-ras construct.

An orthotopic human lung cancer model in nu/nu mice was used to study the effect of an antisense K-ras (AS-K-ras) retroviral construct on tumor growth in vivo. A 2-kilobase genomic AS-K-ras DNA fragment linked to a beta-actin promoter was cloned into the LNSX retroviral vector. The recombinant construct was packaged into GP+envAm12 cells and titers greater than 10(6) colony-forming units/ml were obtained. Irradiated (350 cGy) nu/nu mice were first inoculated intratracheally with 10(5) H460a human large cell lung carcinoma cells which have a codon 61 mutation of the K-ras oncogene. Three days later they received intratracheal instillation of viral supernatant (5 x 10(6) colony-forming units/ml) from either LNSX, LNSX-AS-K-ras, LNSX-sense-K-ras producer cells, or medium daily for 3 days. At autopsy, 30 days after tumor cell inoculation, 90% of the control mice had tumors whereas 87% of mice treated with the LNSX-AS-K-ras viral supernatant were free of tumors. The efficacy of the viral supernatant was dose dependent. Intratracheal administration of retroviral LNSX-AS-K-ras supernatant prevents the growth of human lung cancer cells implanted orthotopically in nu/nu mice.

Animals↗

PubMed1993

Retroviral vector-mediated transduction of K-ras antisense RNA into human lung cancer cells inhibits expression of the malignant phenotype.

A retroviral vector system was developed to transduce a K-ras antisense construct efficiently into human cancer cells. A 2-kb fragment of K-ras gene DNA in antisense orientation was linked to a beta-actin promoter and inserted into retroviral vector LNSX in two different orientations. The constructs were transfected into amphotropic packaging cell line GP+envAm12 followed by alternating transduction between the ecotropic packaging cell line psi-2 and GP+envAm12. Titers up to 9.7 x 10(7) colony-forming units (cfu)/ml were achieved without detectable replication-competent virus. The human large cell lung carcinoma cell line H460a, which has a homozygous codon 61 K-ras mutation, was transduced with an efficiency of 95% after five to seven repeated transductions. DNA polymerase chain reaction (PCR) and genomic DNA Southern blot analysis showed that the retroviral construct was integrated into the genome of H460a cells. K-ras antisense RNA expression was detected in the cells by Northern analysis, slot blot hybridization, and reverse transcriptase-PCR. Translation of the mutated K-ras p21 protein RNA was specifically inhibited, whereas expression of other p21 species was unchanged. Proliferation of H460a cells was suppressed 10-fold following transduction by the antisense construct. Colony formation in soft agarose and tumorigenicity in an orthotopic lung cancer model in nu/nu mice were dramatically reduced in H460a cells expressing antisense K-ras. We conclude that an antisense construct for K-ras can be expressed effectively in a retroviral vector that can efficiently transduce human cancer cells.

3T3 Cells↗

PubMed1993

Pyogenic hepatic abscess.

We reviewed the clinical courses of 37 patients treated for pyogenic liver abscesses. These abscesses were cryptogenic in 38% of the patients, associated with biliary tract or intra-abdominal disease processes in 48%, and hematogenous in 11%. Computed tomography was more accurate (96%) in diagnosing a hepatic abscess than ultrasonography (82%). The majority of the patients were treated initially with percutaneous drainage (18) or needle aspiration drainage (5); treatment failure occurred in 9 of these 23 patients (39%). In contrast, there were no treatment failures in the 9 patients treated with primary operation. Overall, 4 of the 37 patients died (a mortality rate of 11%) but 2 of them died of underlying malignant disease rather than the liver abscess.

Adolescent↗

PubMed1992

Preoperative management of sickle cell patients.

During a 12-year period, 59 patients with sickle cell disease underwent a total of 73 operative procedures. There was a total of 30 non-sickle-cell-related and 7 sickle-cell-related complications for an incidence of 41% and 10% respectively. There were no deaths. When complications were compared between patients that were transfused and those not transfused, there was no difference in the incidence of sickle-cell-related complications with an 8% incidence for the non-transfused group and 10% for the transfused group. A higher incidence of non-sickle-cell-related complications (46% versus 32%) was noted in the transfused group, with atelectasis being the most common complication (p = .29). The type of transfusion therapy did not influence morbidity, since the complication rates in the simple and exchange transfusion groups were similar. In conclusion, our data indicate that routine preoperative blood transfusion does not appear to be beneficial in the surgical sickle cell patient, since preoperative blood transfusions did not reduce the incidence of sickle-cell-related complications.

Adult↗

PubMedDate not supplied

Endovascular treatment of mycotic hepatic artery aneurysm in the hostile abdomen--a case report.

Mycotic hepatic artery aneurysms are rare. This report documents a case in which a mycotic hepatic artery aneurysm was associated with Crohn's disease, renal adenocarcinoma, and a urinary tract infection. Endovascular management of this mycotic hepatic artery aneurysm was successful in the setting of a hostile abdomen based on multiple previous operations, a stoma, and a scarred abdomen.

Adult↗