Critical stages of tumor growth regulation in transgenic mice harboring a hepatocellular carcinoma revealed by distinct patterns of tumor necrosis factor-alpha and transforming growth factor-beta mRNA production

There is now good evidence that cytokines contribute to the regulation of tumor growth. The cytokine-driven modulation of tumor growth was investigated during the progression of a hepatocellular carcinoma (HCC) in SV40 large T tumor antigen transgenic mice. In vivo, an increased rate of liver growth correlated with increased transforming growth factor (TGF)-beta 1 mRNA expression, while the greatest amounts of tumor necrosis factor (TNF)-alpha mRNA were detected earlier during tumor development. Conversely, no particular alteration of IL-1 alpha, IL-1 beta, IL-6, IL-2, IL-4 and IFN-gamma mRNA production could be reported. In vitro, hepatocyte-like tumor cell lines established at two stages, either before or after HCC differentiation, were characterized. The early-stage-derived cell line produced TNF-alpha mRNA, but had barely detectable expression of TGF-beta 1 mRNA, while later-stage- derived cell lines showed the reciprocal pattern. All cell lines displayed a lack of sensitivity to TNF-alpha, although some degree of sensitivity to TNF-alpha could be observed in the presence of actinomycin-D or after treatment with IFN-gamma. The early-stage- derived cell line was sensitive to the growth inhibitory effects of TGF- beta 1, but late-stage-derived tumor cell lines displayed a loss of sensitivity to TGF-beta 1 which correlated with the increased expression of TGF-beta 1 mRNA. Altogether, this suggests that tumor cells contribute to the discrete TNF-alpha and TGF-beta 1 expression patterns during HCC progression. This model of HCC could be of valuable interest to assess the impact of various immunotherapeutic strategies on modulation of tumor growth.      

Mutational analysis of the SOX9 gene in campomelic dysplasia and autosomal sex reversal: lack of genotype/phenotype correlations

It has previously been shown that, in the heterozygous state, mutations in the SOX9 gene cause campomelic dysplasia (CD) and the often associated autosomal XY sex reversal. In 12 CD patients, 10 novel mutations and one recurrent mutation were characterized in one SOX9 allele each, and in one case, no mutation was found. Four missense mutations are all located within the high mobility group (HMG) domain. They either reduce or abolish the DNA-binding ability of the mutant SOX9 proteins. Among the five nonsense and three frameshift mutations identified, two leave the C-terminal transactivation (TA) domain encompassing residues 402-509 of SOX9 partly or almost completely intact. When tested in cell transfection experiments, the recurrent nonsense mutation Y440X, found in two patients who survived for four and more than 9 years, respectively, exhibits some residual transactivation ability. In contrast, a frameshift mutation extending the protein by 70 residues at codon 507, found in a patient who died shortly after birth, showed no transactivation. This is apparently due to instability of the mutant SOX9 protein as demonstrated by Western blotting. Amino acid substitutions and nonsense mutations are found in patients with and without XY sex reversal, indicating that sex reversal in CD is subject to variable penetrance. Finally, none of 18 female patients with XY gonadal dysgenesis (Swyer syndrome) showed an altered SOX9 banding pattern in SSCP assays, providing evidence that SOX9 mutations do not usually result in XY sex reversal without skeletal malformations.      

Comparison of "host cell infiltrates" in patients with follicular lymphoma with and without spontaneous regression

The "host cell infiltrates" in five patients with low-grade follicular lymphoma who had spontaneous regression without therapy were studied with the use of immunohistochemical methods applied to frozen sections. These infiltrates were compared with the "host cell infiltrates" in six patients with follicular lymphoma with progressive disease. The group with progressive disease was selected to be similar to the group with spontaneous regression in age, sex, histologic characteristics, and stage of disease. The patients with spontaneous regression had significantly more T-helper cells in the host cell infiltrate than the control patients. There were no statistically significant differences between the two groups in numbers of cytotoxic/suppressor T-cells, macrophages, Tac-positive cells, Leu-7-positive cells, or proliferating cells.     

蝙蝠葛中的新生物碱——蝙蝠葛新林碱

防已科植物蝙蝠葛(Menispermum daurioum DC.)的根茎,即北豆根,是一种重要的中药,具有清热解毒、消肿止痛等功效。已知含有近二十种生物碱,其中五种属双苄基四氢异喹啉类,即蝙蝠葛碱(dauricine,Ⅰ)、蝙蝠葛诺林碱(daurinoline,Ⅱ)、蝙蝠葛新诺林碱     

Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats

Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is a contaminant of the human food supply, particularly in parts of Africa and Asia. AFB1-induced changes in gene expression may play a part in the development of the toxic, immunosuppressive and carcinogenic properties of this fungal metabolite. An understanding of the-role of AFB1 in modulating gene regulation should provide insight regarding mechanisms of AFB1-induced carcinogenesis. We used three PCR- based subtractive techniques to identify AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential display PCR (DD-PCR), representational difference analysis (RDA) and suppression subtractive hybridization (SSH). Each of the three techniques identified AFB1- responsive genes, although no individual cDNA was isolated by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH were found to represent eight genes that are differentially expressed as a result of AFB1 exposure. Genes whose mRNA levels were increased in cultured primary rat hepatocytes after AFB1 treatment were corticosteroid binding globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin, C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When liver RNA from AFB1-treated male F344 rats was evaluated for transferrin, CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen. Analysis of the potential function of these genes in maintaining cellular homeostasis suggests that their differential expression could contribute to the toxicity associated with AFB1 exposure.