Résumé
<p><b>OBJECTIVE</b>To investigate the effects of all-trans-retinoic acid(ATRA) and polyphenon-100 (PP) on genetic instability of human tumor cells via their role in alteration of microsatellite sequence(MS) and the expression of mismatch repair gene hMLH(1) and hMSH(2) in RER(+) (replication error) cells.</p><p><b>METHODS</b>RER(+) colon cancer cell line was used as a host for lipofection with pCMV-CAR in which a foreign (CA)(14) repeat was inserted in the coding sequence of LacZ reporter gene, resulting in misreading LacZ frame. Any mutation which made the base number of (CA)(14) tract to be 3-fold resumed normal reading frame of LacZ, and thus led to expression of beta-galactosidase. Variable expression of LacZ in the transfectant cells resulting from RATA or PP treatment was measured by OD reading at lambda 620 after X-gal staining. Expression of mismatch repair genes of hMLH(1) and hMSH(2) was examined at mRNA level by reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>ATRA at 1 mu mol/L, 0.1 u mol/L and PP at 3 mu g/ml had no significant inhibitory effect on cell proliferation. After being treated with ATRA or PP for 1 week, the blue cells of RKO transfectant clones were significantly reduced, and this meant the mutation of exogenous (CA)(14) in RKO cells were inhibited. But no expression of hMLH(1) and hMSH(2) was observed.</p><p><b>CONCLUSION</b>The above data showed both ATRA and PP had inhibitory effects on MS instability of cancer and thus demonstrated directly their beneficial role in stabilization of genomic DNA. However, the present authors have not observed any expression of hMLH(1) and hMSH(2) in RKO cells treated with ATRA or PP.</p>
Sujets)
Humains , Protéines adaptatrices de la transduction du signal , Protéines de transport , Catéchine , Pharmacologie , Division cellulaire , Tumeurs du côlon , Génétique , Anatomopathologie , Protéines de liaison à l'ADN , Expression des gènes , Opéron lac , Génétique , Répétitions microsatellites , Génétique , Protéine-1 homologue de MutL , Protéine-2 homologue de MutS , Mutation , Protéines tumorales , Génétique , Protéines nucléaires , Plasmides , Génétique , Protéines proto-oncogènes , Génétique , ARN messager , Génétique , Métabolisme , Transfection , Trétinoïne , Pharmacologie , Cellules cancéreuses en cultureRésumé
Objective To investigate the change of serum insulin like growth factor Ⅰ (IGF Ⅰ) level in newly diagnosed senile patients with type 2 diabetes mellitus (DM) before and after regular insulin (RI) therapy. Methods Body mass index, blood pressure (BP), 24 hour urinary microalbumin (24hUAlb), fasting blood glucose (FBG), 2 hour postprandial blood glucose (P2hBG), serum insulin (Ins) and C peptide (C P), HbA 1c and IGF Ⅰ were measured in 60 senile type 2 DM patients newly diagnosed by oral glucose tolerance test (OGTT) and 40 healthy senile subject (controls); RI 8 U, 6 U, 6 U were injected to type 2 DM patients before three meals respectively. Two days later, above tests were repeated. Insulin resistance index (IR) was calculated. Results The serum IGF Ⅰ levels were (349.0?49.5)?g/L in control group, (231.8?64.4)?g/L and (294.2?46.2)?g/L in patient group before and after RI therapy, The IGF Ⅰ level was significantly lower before RI therapy than that of controls (P