Evaluation of target mRNA cleavage by Aurorakinase B specific siRNA in prostate and hepatic cancer cells and its therapeutic potential in mouse models of liver cancer.

The anti proliferative potential of siRNA26, targeted to Aurora kinase B, in prostate cancer cells is known from a previous study from our laboratory. Here we first show that siRNA26 cleaves at the same position of the target mRNA in the prostate cancer and hepatocellular carcinoma cell lines, PC3 and HepG2 respectively. Aurorakinase B specific siRNA, but not a control siRNA, inhibited PC3 and HepG2 cell proliferation and cell migration. These effects correlated to RNA silencing of Aurorakinase B in both the cell lines. Intra-tumoral administration of HiPerfect complexed siRNA26 inhibited the growth of HepG2 xenografts in SCID mice. In an orthotopic setting, intravenous administration of HiPerfect encapsulated siRNA26 appeared to reduce the severity of multifocal lesions.

Suppression of Tumor Formation and Induction of Natural Killer Cell Activity in BALB/c Nude Mice by Human B7-1 (CD80) Gene Transfer Subcutaneously Injected with Human Hepatocellular Carcinoma Cells (Huh-7) / 대한간학회지

BACKGROUND/AIMS: Immunogene therapy is extensively studied for a therapeutic modality of various cancers. This study was conducted to investigate the efficacy of immunogene therapy using the T-cell costimulatory molecule and human B7-1 (CD80, hB7-1) in an in vivo human hepatocellular carcinoma (HCC) model. METHODS: The stable HCC cell line expressing hB7-1 gene was established using retroviral vector (Huh-7/hB7-1). Of fourteen BALB/c nude mice, 7 were subcutaneously injected with 2 X 10(6) Huh-7/hB7-1 cells, while the other 7 were injected with 2 X 10(6) Huh-7/mock cells as a control group. After the injection, the mice were observed weekly for three months for subcutaneous tumor formation. Assay for natural killer (NK) cell cytotoxicity and serum IFN-gamma was performed at 1 and 2 weeks after inoculation. RESULTS: In BALB/c nude mice inoculated with Huh-7/hB7-1 cells, no tumor growth was observed. BALB/c nude mice inoculated with Huh-7/hB7-1 cells showed significantly increased NK cell activities of splenocytes compared with those with Huh-7/mock cells. Serum IFN-gamma was not measurable at 1 week, but significantly increased at 2 weeks after inoculation to the level of 470 pg/ml in BALB/c nude mice with Huh-7/mock cells and 521 pg/ml in BALB/c nude mice with Huh-7/hB7-1. CONCLUSIONS: Our results demonstrate the in vivo anti-tumor immunity and NK cell activation by transfer of hB7-1 gene into human HCC in xenogeneic BALB/c nude mice model. This approach may provide a tool for the development of immunogene therapies against human malignant tumors.

No mutations found in exons of TP53, H-RAS and K-RAS genes in liver of male Wistar rats submitted to a medium-term chemical carcinogenesis assay

The standart protocol to evaluate the carcionogenic potencial of chemicals is the long-term bioassay in rodents, not performed in developing countries due to its high cost and complex operational procedures. Our laboratory has established an alternative an alternative medium-term bioassay in Wistar rats, also DMBDD assay, based on the paradigm iniation/promotion of chemical carcinogenesis. This method was accepted by the Brazilian Environment Agency (IBAMA) as an official source of evidence of carcinogenity. The aim of this study was to evaluate alterations in exons 5 to 8 of the tumor suppressor gene TP53 and exons 1 and 2 of oncogenes K-RAS and H-RAS in preneoplastic hepatic lesions observed in DMBDD assay. The characterization of these alterations may contribute to the recognition of patterns of damage in critical genes, as well as to suggest mechanisms of action of the compounds tested in the protocol. Sixty male wistar rats were separeted into3 groups? the first was treated with no chemicals; the second received five initiaing agents and the third received initiation followed by phenobarbital. Liver DNA samples (obtained from formalin-fixed and parafin-fixed and paraffin-embedded tissues after histological analysis) were evaluated by the non-isotopic PCR-SSCP technique. No changes in any analyzed exons were detected by the PCR-SSCP banding pattern in all experimental groups. This suggests that liver in exons 5 to 8 of TP53 and exons 1 and 2 of H-RAS are not among the early molecular alterations occuring in the hepatic carcinogenesis process by the DMBDD protocol in male Wistar rats

Diferencias entre los ácidos ribonucleicos mensajeros de hígado normal y de hepatoma de Novikoff / Differences between the messenger ribonucleic acids of the normal liver and Novikoff's hepatoma

En la activación de varios genes en algunas células cancerosas aparentemente se requiere que se desencadene una cascada de eventos, que trae como consecuencia la transcripción de diversos genes; al mismo tiempo, otros genes son reprimidos. El propósito de este trabajo fue investigar si existen diferencias en la transcripción del ácido ribonucleico mensajero (mRNA) del hígado normal y del hepatoma de Novikoff. En todos los experimentos se utilizaron ratas macho adultas Sprague Dawley. La extracción del RNA total de bazo, hígado y células del hepatoma de Novikoff se llevó a cabo con el método de Schueltz y la separación del mRNA se realizó utilizando una columna de celulosa-ácido oligotimidílico, de acuerdo a lo señalado por Aviv y Leder. La cuantificación del mRNA mostró que las células del hepatoma de Novikoff tienen el doble de esta macromolécula comparadas con el hígado normal de rata

Mecanismo teórico de la hepatocarcinogénesis / Theoretical mechanism of ethionine hepatocarcinogenesis

En resumen, parece ser que el proceso necesario, al menos conceptualmente que le permita a uno construir una noción adecuada del mecanismo involucrado durante la carcinogénesis inducida por etionina, puede ser relevante a un proceso más general y fundamental aplicable a todos los carcinógenos. Se ha descrito un intento que trata de aportar un mecanismo considerado en este artículo, también enfatiza la importancia de la activación de proteínas embriónicas como un ejemplo de un proceso más general que se requiere para la carcinogénesis

Differential amplification and expression of c-myb oncogene in Zajdela ascitic hepatoma.

Organisation and expression of c-myb protooncogene have been studied in a heterogeneous tumour the Zajdela ascitic hepatoma (ZAH). The myb gene is selectively amplified in the more tumorigenic subpopulation of the tumour while the non-lethal subpopulation does not show any change. Analysis of transcripts of the myb gene in tumorigenic versus nontumorigenic cells shows that the level of amplification of the gene does not correspond to the level of its transcription. Results have been discussed in the light of existing evidence regarding the role of c-myb gene expression during cell cycle.