To explore whether the imprinting status of IGF-2 in the malignant epithelial ovarian tumors is different from that in benign tumors, the target sequences (DNA and RNA) which contain a polymorphism site for ApaI restriction endonuclease digestion were amplified with PCR and RT-PCR methods. Then the PCR/RT-PCR products were digested by ApaI. The IGF-2 transcriptional pattern came out from the results of endonucleases digestion. Among the 36 cases of benign epithelial ovarian tumors, 20 were heterozygous for ApaI locus and all showed genomic imprinting. While in the malignant group, 22 were heterozygous for ApaI locus but six were found to lose imprinting. Significant differences existed between the two groups (P < 0.05). Loss of imprinting of IGF-2 may serve as a marker for differentiating the malignant ovarian cancers from the benign ones. In a new field of molecular genetics, our research provides an experimental basis for genetic diagnosis and treatment of the ovarian cancers.
Cystadenocarcinoma, Serous/*genetics ; Cystadenoma/genetics ; *Genomic Imprinting ; Insulin-Like Growth Factor II/*genetics ; Ovarian Neoplasms/*genetics

OBJECTIVEIntrauterine growth retardation (IUGR) may contribute to the disorder of development of fetal brains. L-arginine has been known to be effective in blood vessel distension and improving the blood circulation of placentas. Recent studies have shown that L-arginine can ameliorate the placental hypoxia and improve the development of fetus. This study aimed to explore the effects of L-arginine on the expression of insulin-like growth factor (IGF)-I, IGF-II, IGF binding protein-3(IGFBP3)and IGF-I mRNA in brains of IUGR rats and the possible mechanisms of L-arginine.

METHODSThirty-six pregnant rats were randomly assigned into four groups: Control, Model, Low dose L-arginine (100 mg/kg) and High-dose L-arginine (200 mg/kg L-arginine) groups (n=9 each). IUGR was induced by passive smoking in rats from the last three groups. L-arginine was administered for the last two groups between days 8 and 20 of gestation. On day 21 of gestation, the pup rats were delivered by cesarean section. The levels of IGF-I, IGF-II and IGFBP3 in the brains of pup rats were measured by enzyme-linked immunoadsordent assay (ELISA) and the expression of IGF-I mRNA was detected by fluorescence quantitative PCR (FQ-PCR).

RESULTSThe levels of IGF-I, IGF-II and IGF-I mRNA expression in the Model group were significantly lower than in the Control group, with the IGF-I levels of 0.789 +/- 0.062 ng/mg vs 0.947 +/- 0.042 ng/mg, the IGF-II levels of 0.270 +/- 0.020 ng/mg vs 0.374 +/- 0.015 ng/mg and the IGF-I mRNA expression of (13.12 +/- 1.39) x 10(4) cps/mug RNA vs (21.28 +/- 3.54) x 10(4) cps/mug RNA (P < 0.01). In contrast, the IGFBP3 levels in the Model group were significantly higher than in the Control group (0.253 +/- 0.011 ng/mg vs 0.089 +/- 0.015 ng/mg; P < 0.01). Low or high dose L-arginine treatment increased significantly the IGF-I levels from 0.789 +/- 0.062 ng/mg (Model group) to 0.937 +/- 0.067 ng/mg (low dose group) or 0.858 +/- 0.077 ng/mg (high dose group), the IGF-II levels from 0.270 +/- 0.020 ng/mg (Model group) to 0.318 +/- 0.018 ng/mg (low dose group) or 0.354 +/- 0.021 ng/mg (high dose group) and the IGF-I mRNA expression from (13.12 +/- 1.39) x 10(4) cps/mug RNA (Model group) to (19.24 +/- 2.48) x 10(4) cps/mug RNA (low dose group) or (17.35 +/- 2.30) x 10(4) cps/mug RNA (high dose group) (P < 0.01). The IGFBP3 levels were significantly reduced after low or high dose L-arginine treatment (0.132 +/- 0.006 ng/mg or 0.146 +/- 0.009 ng/mg) compared with those of the Model group (0.253 +/- 0.011 ng/mg) ( P < 0.01).

CONCLUSIONSL-arginine can increase the levels of IGF-I and IGF-II and the IGF-I mRNA expression, and decrease the IGFBP3 level in the brain of rats with IUGR induced by passive smoking, thereby offering protective effects against IUGR.

Animals ; Arginine ; pharmacology ; therapeutic use ; Female ; Fetal Growth Retardation ; metabolism ; prevention & control ; Insulin-Like Growth Factor Binding Protein 3 ; analysis ; Insulin-Like Growth Factor I ; analysis ; genetics ; Insulin-Like Growth Factor II ; analysis ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar

To explore whether the imprinting status of IGF-2 in the malignant epithelial ovarian tumors is different from that in benign tumors, the target sequences (DNA and RNA) which contain a polymorphism site for ApaI restriction endonuclease digestion were amplified with PCR and RT-PCR methods. Then the PCR/RT-PCR products were digested by ApaI. The IGF-2 transcriptional pattern came out from the results of endonucleases digestion. Among the 36 cases of benign epithelial ovarian tumors, 20 were heterozygous for ApaI locus and all showed genomic imprinting. While in the malignant group, 22 were heterozygous for ApaI locus but six were found to lose imprinting. Significant differences existed between the two groups (P < 0.05). Loss of imprinting of IGF-2 may serve as a marker for differentiating the malignant ovarian cancers from the benign ones. In a new field of molecular genetics, our research provides an experimental basis for genetic diagnosis and treatment of the ovarian cancers.
Cystadenocarcinoma, Serous ; genetics ; Cystadenoma ; genetics ; Female ; Genomic Imprinting ; Humans ; Insulin-Like Growth Factor II ; genetics ; Ovarian Neoplasms ; genetics

BACKGROUND: Insulin-dependent diabetes mellitus (IDDM) is caused by the autoimmune destruction of pancreatic beta-cells. Susceptibility to IDDM appears to depend on more than one genetic locus. Evidence of a genetic linkage for IDDM2 was found in male meioses from French and North American populations. It is linked to maternal imprinting (i.e. monoalleleic expression of the insulin gene) that is considered the most likely cause of these gender-related differences. IGF2 is expressed only in the paternal allele and, therefore, is considered a candidate gene for IDDM2 transmission because of its important autocrine/paracrine effects on the thymus, lymphocytes and pancreas. Nevertheless, it remains controversial whether the parental origin of IDDM2 influences IDDM susceptibility. METHODS: Using PCR and semi-quantitative RT-PCR, we analyzed the INS/ PstI+1127 and IGF2/ApaI polymorphisms and RNA expression level between PstI (+/-) and PstI (+/+) to determine genotype and allele-specific expression of the INS and IGF2 genes. RESULTS: INS/PstI (+/+) and IGF2/ApaI (+/-) were observed in 36 (97.3%) of 37 IDDM patients and in 29 (72.5%) of 40 IDDM patients, respectively. The presence of both IGF2 alleles in RNA was observed in 21 (91.6%) of 24 IDDM patients. Our results show a 3-fold increase in RNA expression from PstI (+/-) allele over PstI (+/+) allele. CONCLUSION: Our conclusion does not entirely exclude IGF2 as the gene involved in IDDM2, even though the parental effect of IDDM2 transmission is not related to IGF2 maternal imprinting. The INS genotype appeared mostly in the PstI (+/+) homozygote and, therefore, we could not explain the INS imprinting pattern in Korean type 1 diabetic patients. Genetic differences between populations may account for the discrepancy between Korean type I diabetic patients and American or French type I diabetic patients.
Adolescent ; Child ; Diabetes Mellitus, Insulin-Dependent/*genetics ; Female ; *Genomic Imprinting ; Human ; Insulin/*genetics ; Insulin-Like Growth Factor II/*genetics ; Korea ; Male ; Sex Factors

BACKGROUNDThe insulin-like growth factor signaling pathway plays an important role in the modulation of cell growth and proliferation. The aim of this study was to investigate the role of polymorphisms of the insulin-like growth factor 2 (IGF2) and IGF-binding protein 3 (IGFBP3) genes, which encode key proteins of this pathway, as risk factors for gastric carcinoma (GC).

METHODSA case-control study including 404 histologically confirmed GC patients and 424 healthy controls of the same ethnicity was conducted to retrospectively investigate the genetic polymorphisms of two genes, IGF2+820A>G (rs680) and IGFBP3 A-202C (rs2854744). Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using Logistic regression.

RESULTSThe IGF2 genetic variants examined contributed to GC risk individually (OR, 1.26; 95% CI, 1.08-1.46). The genotype frequencies of IGFBP3 A-202C were not significantly different between the cancer cases and controls (P > 0.05). Compared to the IGF2 AA genotype, carriers of one variant combined genotype were more pronounced among young subjects (<60 years), male subjects, never smokers, and those with a family history of cancer (OR = 1.36, 95% CI = 1.09-1.72, P < 0.05; OR = 1.61, 95% CI = 1.28-2.08, P < 0.05; OR = 1.46, 95% CI = 1.11-1.98, P < 0.05; OR = 1.53, 95% CI = 0.91-2.6, P < 0.05; respectively). Moreover, when the combined effects of the risk genotypes were investigated, significant associations were detected between highrisk genotypes in IGF2 and IGFBP3 (OR, 2.47; 95% CI, 1.75-3.49).

CONCLUSIONSOur results suggest that polymorphic variants of the IGF2 genes modulate gastric carcinogenesis. Moreover, when the IGF2 and IGFBP3 variants are evaluated together, a greater effect on GC risk is observed.

Adult ; Aged ; Case-Control Studies ; China ; Female ; Genetic Predisposition to Disease ; genetics ; Genotype ; Humans ; Insulin-Like Growth Factor Binding Protein 3 ; genetics ; Insulin-Like Growth Factor II ; genetics ; Logistic Models ; Male ; Middle Aged ; Polymorphism, Genetic ; genetics ; Stomach Neoplasms ; genetics

To explore the relationship between Insulin-like growth factor (IGF)-I , -II and lung development in neonatal rats. 80 timed pregnant Sprague-Dawley (SD) rats were randomly divided into 4 groups (n=20): group A (Control group), group B (Dexamethasone (DEX) 1 group), group C (DEX 2 group), group D (retinoic acid (RA) group). 20 pregnant rats in group A, B and D were injected subcutaneously or intraperitoneally with vehicle (NS), DEX, or RA respectively during gestational day 16 to 18. All newborn rats in group C were subcutaneously injected with DEX at day 1 to 3 after birth. The lung tissue was obtained at the following times: fetuses at gestational ages of 18, 20 and 21 days, and 1, 3, 5, 7, 10, 14 and 21 days after birth. Lung tissues were used for histopathological study, the polypeptides analysis of IGF- I, -II (immunohistochemistry and Western blot) and mRNA analysis ( RT- PCR). The results showed that the strongest expression of IGF- I in group A and D occurred at ages of 5-7 days (alveolar stage). The stronger their expressions, the better the alveolar develop. The peak stage of expression in group B occurred earlier, on the day 3 after birth. Compared with group A, the expression of IGF-I during gestation age of 18 days to age of 3 days in group B were significantly higher (P<0.01), but significantly lower at other time points (P<0.01). The expression of IGF-I was lower in group C all the time and always higher in group D than those in group A (P<0.01). The peak expression of IGF-II took place at the gestation age of 18 days, then gradually dropped to trace. During 18 days of gestation to age of 3 days, the expression of IGF-II in group B was significantly higher than that in group A (P<0.01). No difference was found among all other groups. The change in the expression of IGF-I, -II mRNA in all 4 groups was similar to that of their polypeptides. The results suggested that there is a close linking between IGF-I , -II and lung development in newborns. The IGF-II works at early stage and the that of IGF- I works at the stage of new septa formation and alveoli maturation. The stronger their expressions, the more mature the lung development.
Animals ; Animals, Newborn ; Dexamethasone ; pharmacology ; Female ; Insulin-Like Growth Factor I ; biosynthesis ; genetics ; Insulin-Like Growth Factor II ; biosynthesis ; genetics ; Lung ; embryology ; growth & development ; metabolism ; Male ; Pregnancy ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tretinoin ; pharmacology

OBJECTIVETo investigate the selective killing effect of herpes simplex virus-thymidine kinase/ganciclovir (HSV-tk/GCV) suicide gene system controlled by human IGF-II P4 promoter on HCC cells in vitro.

METHODSRecombinant shuttle plasmid vectors driven by IGF-II P4 promoter and driven by CMV promoter were constructed by techniques of gene recombination. The recombinant shuttle plasmids were then transfected into HepG2 and HeLa cells by techniques of lipidosome transfection. EGFP expression was detected by fluoroscopy. Tk and EGFP mRNA expression were detected by RT-PCR. The selective killing effect after GCV application was determined with MTT method. Statistical analysis was performed with ANOVA analysis.

RESULTSIdentification of pDC316-tkEGFP-P4 by enzyme digestion and sequencing analysis showed that the construction of the recombinant shuttle plasmid was correct. It was found that green fluorescence protein could only be seen in HepG2 cells, not in HeLa cells. The results of RT-PCR showed only two bands could be seen in the samples of pDC316-tkEGFP-P4 transfected HepG2 cells. The growth of HepG2 cells transfected with pDC316-tkEGFP-CMV and pDC316-tkEGFP-P4 were inhibited remarkably, the growth inhibition rates were 6.95% +/- 0.67%, 24.99% +/- 1.53%, 49.68% +/- 1.68%, 71.85% +/- 3.28% and 4.83% +/- 0.35% vs 17.34% +/- 1.15%, 30.17% +/- 1.30%, 40.39% +/- 0.82% (F = 24.055, P < 0.05), respectively. The growth of HeLa cells transfected with pDC316-tkEGFP-CMV were also inhibited, the growth inhibition rates were 6.36% +/- 0.83%, 23.95% +/- 1.72%, 45.13% +/- 1.64% and 69.38% +/- 3.17%, respectively. The growth of HeLa cells transfected with pDC316-tkEGFP-P4 was not inhibited. The growth inhibition rates were 0.91 +/- 0.04, 1.18 +/- 1.32, 1.19 +/- 0.10 and 1.32 +/- 0.05 (F = 26.469, P < 0.01) , respectively.

CONCLUSIONThe shuttle plasmid vector carrying the tkEGFP fusion protein gene driven by IGF-II P4 promoter has been constructed successfully and its specific expression in HepG2 cells provided the basis for targeted gene therapy for HCC.

Cell Line, Tumor ; Genes, Transgenic, Suicide ; genetics ; Genetic Vectors ; Humans ; Insulin-Like Growth Factor II ; genetics ; pharmacology ; Plasmids ; Promoter Regions, Genetic ; Thymidine Kinase ; genetics ; Transfection

OBJECTIVETo study the imprinting status of IGF2 and phenotypes of loss of imprinting (LOI) in cord blood of neonates of Chinese Han population and to investigate relative factors to LOI.

METHODSCord blood of 1010 Chinese Han newborns were collected and the imprinting status of IGF2 was detected by reverse transcription-PCR(RT-PCR) and restriction fragment length polymorphism.The relationships between LOI and fetal growth indices, features of parents and grandparents, clinical characteristics were analyzed.

RESULTSOf all cases, 42.8% (432/1010) were heterozygous for a polymorphism of Apa I site in exon 9 of IGF2, while 21.6%(66/306) displayed IGF2 LOI. Maternal factors including average age, gestational age, BMI pre-pregnancy, weight gain during pregnancy and the level of HB, HCT, and other indices of biochemistry in their second and third trimester were not correlated with LOI expression. However in newborns with fathers older than 35 yrs, 31.7%(19/60) displayed LOI, which was significantly more common than that in newborns with younger fathers (P< 0.05, chi square is 4.69). There were no difference in birth weight (BW) between normal imprinting and LOI groups. But if the newborn's weights were in 2500-2999 g, LOI was 6.25%(2/32), which was significantly lower than that in 3000 g group (P< 0.05, chi square is 4.89). In groups with BW being less than 2500 g and more than/equal to 4000 g, the LOI newborn's blood glucose was decreased significantly after 2 hrs (P< 0.01, t is 7.47 and 10.9).

CONCLUSIONIn newborns of Chinese Han population, 21.6% showed IGF2 LOI in cord blood. IGF2 LOI may have some influences on fetal growth. Paternal age is associated with LOI.

Asian Continental Ancestry Group ; genetics ; China ; Female ; Fetal Blood ; metabolism ; Genomic Imprinting ; genetics ; Humans ; Infant, Newborn ; Insulin-Like Growth Factor II ; genetics ; Pregnancy ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVESTo study the inhibitory effect of specially synthesized oligodeoxynucleotide (SODN) on malignant phenotype of human hepatocellular carcinoma Hep3B cells by complementary binding to the fourth promoter of IGF-2 gene.

METHODSA SODN was synthesized according to the sequence of the fourth promoter of IGF-2 gene, and was then transfected into Hep3B cells which overexpressed IGF-2. IGF-2 gene transcription activity and protein expression were assayed by RT-PCR and Western blot methods. The effect on cell growth by SODN was estimated by MTT method, and the effect on cell cycle distribution was measured by flow cytometry. Colony formation assay was performed on 6-well tissue culture dishes. Alteration on mobility and invasiveness were studied used transwell plates.

RESULTSIGF-2 mRNA and protein levels in Hep3B cells transfected with SODN were significantly lower in comparison with those in control groups (Hep3B cells and Hep3B cells transfected with a control oligodeoxynucleotide). Results also showed that SODN did not have inhibitory effects on cell growth and mobility of Hep3B cells, but did have an effect on its colony formation and invasiveness.

CONCLUSIONSODN has inhibitory effect on IGF-2 expression in Hep3B cells as a molecular switch, which partially alterates the malignant phenotype of this cell line.

Carcinoma, Hepatocellular ; pathology ; Humans ; Insulin-Like Growth Factor II ; biosynthesis ; genetics ; Liver Neoplasms ; pathology ; Neoplasm Proteins ; biosynthesis ; genetics ; pharmacology ; Oligonucleotides, Antisense ; biosynthesis ; genetics ; pharmacology ; Phenotype ; Tumor Cells, Cultured

Animals ; Cells, Cultured ; Dioxins ; pharmacology ; Insulin-Like Growth Factor II ; genetics ; metabolism ; Osteoblasts ; drug effects ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar