Biomedical subjects

Hee Jung An

Publications and source records attributed to Hee Jung An.

15 recordsLinked to original sources

PubMed2006

Differential expression profiling of genes in a complete hydatidiform mole using cDNA microarray analysis.

OBJECTIVES: To gain a better understanding of the genes involved in the pathogenesis of gestational trophoblastic diseases, we evaluated the genome-wide expression levels of genes in complete hydatidiform mole (H-mole) as compared to normal placenta using cDNA microarray technique. METHODS: The expression profiles of complete H-mole tissues were compared with those of normal placenta using cDNA microarray technique. The data obtained from 10,305 human genes were normalized by the print-tip-based LOWESS method. Significance analysis of microarray (SAM) was used to identify genes with statistically significant changes in expression. The expression levels of genes which showed significant differences between normal early placenta and complete H-mole tissues were further confirmed by RT-PCR. RESULTS: A cDNA microarray analysis consisting of 10,305 human genes revealed significant changes in the expression of 213 genes, with 91 genes being upregulated and 122 being downregulated. SAM revealed significant changes in gene expression, including those associated with signal transduction, cell structure, transcription, and apoptosis. Further RT-PCR analysis of altered gene expression in mole tissues supported the microarray analysis results. We confirmed the upregulation of TLE4, CAPZA1, PRSS25, RNF130, and USP1 in complete H-mole tissues. Moreover, our study provides the first evidence that ELK3, LAMA3, LNK, STAT2, and TNFRSF25 are downregulated in complete H-mole compared to normal early placenta tissues. CONCLUSIONS: These findings provide a large body of information regarding gene expression profiles associated with complete H-mole tumorigenesis and allow the identification of potential targets for tumor prevention or therapy.

DNA, Complementary↗

PubMed2006

Elevation of cyclin B1, active cdc2, and HuR in cervical neoplasia with human papillomavirus type 18 infection.

Over 30 cervical epitheliotrophic HPV types may lead to altered biological functions that affect the clinical outcome of HPV infection. In order to determine the regulatory mechanism and effect of different HPV subtypes, we performed functional assays on cdc2, cyclinB1 and HuR in human uterine cervical samples. After confirming 22 HPV types among 95 cervical swabs, 10 cervical tissues, and seven established cell lines using a DNA chip, we evaluated the functional activities of G2 molecules assays, that included; western blotting for cyclin B1, cdc2 and phospho-cdc2 (Y15 and T161), immunoprecipitation for cdc2, a nuclear extraction fractional assay, and RT-PCR for cyclin B1. The expression of cyclin B1 was found to be dependent on HPV type, and was particularly overexpressed in high-risk types, whereas cdc2 was ubiquitously expressed irrespective of HPV type. Phospho-cdc2 and cyclin B1, however, were most intense in HPV18 infected cervical samples. Furthermore, the HuR stabilizing factor of the cyclin B1 transcript was upregulated in HPV 18 infected swabs. Moreover, SiHa cell line showed weaker G2 functional activity than the HeLa cell line. This study demonstrates that HPV-18 decreases the fidelity of mitotic checkpoints and increases cdc2-associated histone H1 kinase activity relative to control populations, and further shows that the G2 checkpoint is aberrant by virtue of the stabilization of cyclin B1 mRNA through the upregulation of HuR protein and the functional form of cdc2, especially in cases with HPV 18 infected cervical lesions.

Antigens, Surface↗

PubMed2006

Comparative proteomics of ovarian epithelial tumors.

We analyzed 12 ovarian epithelial tumors using 2D PAGE-based comparative proteomics to construct intra- and inter-tumoral distance map trees and to discover surrogate biomarkers indicative of an ovarian tumor. The analysis was performed after laser microdissection of 12 fresh-frozen tissue samples, including 4 serous, 5 mucinous, and 3 endometrioid tumors, with correlation with their histopathological characteristics. Ovarian epithelial tumors and normal tissues showed an apparent separation on the distance map tree. Mucinous carcinomas were closest to the normal group, whereas serous carcinomas were located furthest from the normal group. All mucinous tumors with aggressive histology were separated from the low malignant potential (LMP) group. The benign-looking cysts adjacent to the intraepithelial carcinoma (IEC) showed an expression pattern identical to that of the IEC area. The extent of change on the lineages leading to the mucinous and serous carcinoma was 1.98-fold different. The overall gene expression profiles of serous or endometrioid carcinomas appeared to be less affected by grade or stage than by histologic type. The potential candidate biomarkers screened in ovarian tumors and found to be significantly up-regulated in comparison to normal tissues were as follows: NM23, annexin-1, protein phosphatase-1, ferritin light chain, proteasome alpha-6, and NAGK (N-acetyl glucosamine kinase). In conclusion, ovarian mucinous tumors are distinct from other ovarian epithelial tumors. LMP mucinous tumors showing histologically aggressive features belong to mucinous carcinoma on the proteomic basis.

Adult↗

PubMed2006

[A case of hemophagocytic syndrome with terminal ileal ulcerations].

Reactive hemophagocytic syndrome or hemophagocytic lymphohistiocytosis, is characterized by the proliferation of benign histiocytes showing phagocytosis of blood cells in hematopoietic organs including bone marrow, spleen, or lymph nodes, accompanied by fever, hepatosplenomegaly, hepatic dysfunction, pancytopenia, and hypertriglyceridemia. The pathogenesis of reactive hemophagocytic syndrome is unknown. It is often associated with infection, malignant neoplasm, autoimmune disease, drugs and various immunodeficiencies. The prognosis of this syndrome is poor and the causes of death are hemorrhage, infection, or multiorgan failure. We experienced a case of hemophagocytic syndrome with terminal ileal ulcers, not associated with other causes. Thus, we report this case with a review of literatures.

Adult↗

PubMed2005

Loss of Cyclin B1 followed by downregulation of Cyclin A/Cdk2, apoptosis and antiproliferation in Hela cell line.

Recent studies have shown that Cyclin B1 is overexpressed in various tumor types but present at low levels in normal tissues. To explore the possibility of employing Cyclin B1 as an anticancer target, we knocked down Cyclin B1 in an HeLa cell line using RNA interference (RNAi). Subsequently, we monitored cell cycle-related molecules by Western blot together with immunofluorescence and determined cell cycle distribution by flow cytometry. XTT and soft agar colony growth experiments were performed to detect cell viability and proliferation. Furthermore, we analyzed cell apoptosis by measuring Bcl-2 and Bax protein level and DNA-ladder assay. After performing Cyclin B1 RNAi, Cyclin B1, Cyclin A and Cdk2 protein levels were found to be markedly downregulated, whereas Cdc2 was almost unaffected; S-phase fraction increased significantly; HeLa cell viability and cell colony forming ability were markedly diminished after the RNAi; Bcl-2 was noticeably attenuated but Bax was hardly changed; and HeLa cells displayed typical DNA ladder. The loss of Cyclin B1 resulted in the downregulation of Cyclin A and Cdk2, S-phase delay and eventually led to cell apoptosis and the decrease of cell viability and proliferation. Our studies suggest that Cyclin B1 may be a promising anticancer target.

Apoptosis↗

PubMed2005

The effect of sonication on simulated osteoarthritis. Part II: alleviation of osteoarthritis pathogenesis by 1 MHz ultrasound with simultaneous hyaluronate injection.

In our previous study, we demonstrated the effects of ultrasound (US) on the delivery of hyaluronan (HA) into the synovium, even at molecular sizes as high as 3000 kDA. We hypothesized that a combined therapy with US and HA would have synergistic effects on alleviating the pathogenesis of osteoarthritis (OA). In the present study, we evaluated the effectiveness of sonication on the progress of induced OA in rabbits. We measured the cartilage degradation and inflammation, synovial fluid amount along with protein content and, finally, performed histologic analyses of the integrity of the cartilage and synovium. Low-intensity continuous US at 1 MHz, 400 mW/cm2 was applied to the knees for 10 min bid. Combined treatment with US and HA most strikingly reduced total synovial fluid volume and also significantly alleviated the OA-induced accretion of total protein, proteoglycan and prostaglandin E2 in the synovial fluid. It also attenuated the release of collagen type II and matrix metalloproteinase-3 in the OA-induced joint to normal levels. Histopathology revealed that combined HA and US treatment also reduced the severity of OA-induced structural damages in the cartilage and synovium. The effectiveness of HA with regard to the alleviation of OA pathogenic changes can be greatly enhanced by the simultaneous treatment with HA and US.

Animals↗

PubMed2005

Her2 genotype and breast cancer progression in Korean women.

The amplification and overexpression of Her2 proto-oncogene have been found to be associated with the development and progression of human breast cancer. A polymorphic valine allele at codon 655 of the Her2 gene (Her2(V655)) was suggested by some authors to be a susceptible genetic factor for the development of breast cancer. The Her2 polymorphism at codon 655 was investigated in 304 Korean women including 177 patients with breast cancer. The association between Her2 genotype and Her2 protein overexpression was also examined in breast cancers by immunohistochemistry. Her2(V655) was not associated with a significant breast cancer risk (odds ratio (OR), 1.792; 95% confidence interval (CI), 0.459-6.991). The frequency of homozygous or heterozygous valine allele increased in stage 2 patients (OR, 1.67; 95% CI, 0.67-4.19), and patients in stages 3 and 4 (OR, 3.36; 95% CI, 0.85-13.42) compared to patients in stage 0. However, an association between the presence of the valine allele and the overexpression of Her2 protein could not be demonstrated. These results suggest that Her2 polymorphism at codon 655 is not associated with the development of breast cancer in Korean women. However, there is a possibility that the valine allele at codon 655 might be related to increased risk of breast cancer progression.

Adult↗

PubMed2003

Correlation of cervical carcinoma and precancerous lesions with human papillomavirus (HPV) genotypes detected with the HPV DNA chip microarray method.

BACKGROUND: Human papillomavirus (HPV) infection is considered to play an important role in the development of cervical carcinoma, and it is known that certain HPV types, such as HPV-16 and HPV-18, are highly associated with cervical carcinoma. However, the pathologic behavior of other HPV types remains unclear. Recently, a new HPV detection technique, the HPV DNA chip, was introduced. The HPV DNA chip harbors 22 HPV probes and has the advantage of being able to detect 22 HPV types simultaneously. To evaluate the quality of the HPV DNA chip method and to identify HPV types related to cervical carcinoma and precancerous lesions, the authors performed HPV typing in cervical specimens from 1983 patients and compared their cytologic and histologic diagnoses. METHODS: The HPV DNA chip was used for HPV typing. Among 1983 patients who were tested for HPV types, cervical smear cytology was performed in 1650 patients, and 677 of those patients underwent cervical biopsy. RESULTS: Among the 1650 smears that were examined cytologically, 92.7% (114 of 123 smears) of low-grade squamous intraepithelial lesions (LSILs), 98.1% (106 of 108 smears) of high-grade squamous intraepithelial lesions (HSILs), and 96.3% (51 of 53 smears) of carcinomas were HPV positive, compared with only 35.1% of smears with normal cytology that were HPV positive. HPV-16 was the most prevalent type (chi-square test; P < 0.01) in LSILs (28.5%), in HSILs (51.9%), and in carcinomas (62.5%) followed by HPV-58 and a group of low-risk types (HPV-6, HPV-11, HPV-34, HPV-40, HPV-42, HPV-43,and HPV-44) in LSILs. HPV-58 (15.7%), HPV-18 (6.7%), and HPV-52 (4.6%) were the next most prevalent types after HPV-16 in HSILs. HPV-18 (11.4%) and HPV-58 (11.4%) were the second most common types in carcinomas. HPV-58 had the highest positive predictive value (54.9%) for the detection of histologically confirmed HSIL or carcinoma, whereas HPV 16 had the highest negative predictive value (80.6%). The sensitivity (96.0%) of the HPV test using the DNA chip method for detecting HSIL or carcinoma was superior compared with the sensitivity of cytologic diagnosis (83.6%). CONCLUSIONS: The HPV DNA chip provides a very sensitive method for detecting 22 HPV genotypes with reasonable sensitivity (96.0%) and reasonable negative predictive value (96.9%), and it overcomes the low sensitivity of cytologic screening for the detection of HSIL or carcinoma. HPV-58, HPV-52, and HPV-56, as well as HPV-16 and HPV-18, were associated highly with HSIL and carcinoma in the current large series. In addition, multiple HPV infection was associated less frequently with cervical carcinoma and with precancerous lesions compared with normal cytology.

Adult↗

PubMed2003

Altered imprinting, promoter usage, and expression of insulin-like growth factor-II gene in gestational trophoblastic diseases.

OBJECTIVE: We aimed to understand the involvement of imprinted genes in the pathogenesis of gestational trophoblastic diseases (GTD) such as hydatidiform mole (H-mole) and gestational trophoblastic tumors (GTT). METHODS: An allelic-typing assay was performed using a PCR-RFLP-based method for identification of heterozygous informative cases. The usage of insulin-like growth factor-II (IGF2) promoters was examined by RT-PCR using promoter-specific primers. The mRNA expression of IGF2 and H19 was quantified using a densitometer. RESULTS: The imprinting of IGF2 and H19 was maintained in all normal placenta tissues (n = 15) but relaxed in GTD (n = 47). Loss of imprinting (LOI) of IGF2 was in the order of GTT (57%) > complete H-mole (43%) > partial H-mole (25%). Similarly, LOI of H19 was in the order of GTT (40%) > complete H-mole (18%) > partial H-mole (0%). Promoter usage pattern of IGF2 changed with gestation stage of normal placentae and GTD. In normal placentae, the usage of promoter P1 was higher than that of P4 in the first trimester but lowered in the full term. H-mole and GTT predominantly used promoter P1 with relative silencing of promoter P4. Although normal early placenta and various GTD tissues showed the similar usage of IGF2 promoter P1, GTT tissues revealed the higher expression levels of IGF2 but a down-regulation of H19 relative to the normal early placentae. CONCLUSIONS: These results suggest that LOI, deregulation of IGF2 promoters, and the altered expression levels of IGF2 and H19 genes might be associated with the progression of GTD.

Alleles↗

PubMed2003

Regeneration of hepatocyte 'buds' in cirrhosis from intrabiliary stem cells.

BACKGROUND/AIMS: In massive hepatic necrosis, hepatic stem cells constitute a canal of Hering derived, cytokeratin 19 (CK19) positive 'ductular reaction' (DR). Whether DRs in cirrhosis are activated stem cells (so called 'buds') or biliary metaplasia of cholestatic, injured hepatocytes is still debated. We investigate derivation of intraseptal hepatocytes (ISHs) from DRs and from the biliary tree in cirrhosis. METHODS: Explants of hepatitis B and C, alcohol, primary biliary cirrhosis and primary sclerosing cholangitis-related cirrhosis were examined. ISHs were quantified and their associations with DRs and cholestasis recorded. 3D-reconstruction of ISHs and nearby bile ducts was performed in blocks from hepatitis C and primary sclerosing cholangitis cirrhosis. RESULTS: Seven hundred seventy five/830 (94%) ISHs were associated with CK19 positive DRs. ISHs without ductular reactions were more likely to show cholestatic features (P<0.0001). In 3D, ISHs were seen to bud directly from the biliary tree. In summary: ISHs: (1) are usually associated with stem cell-like DRs; (2) are rarely cholestatic, leaving the associated DRs unexplained; and (3) are linked to the biliary tree in 3D. Dynamic proliferation rates in hepatitis C over time suggest that hepatocyte replication diminishes in late stages, with an associated activation of the biliary stem cell compartment. CONCLUSIONS: We therefore suggest that the biliary tree, from at least its smaller branches up to the canals of Hering, are composed of or at least harbor facultative hepatic stem cells, and that ISH largely represent 'buds' of newly formed hepatocytes.

Biliary Tract↗

PubMed2003

Genotyping of 22 human papillomavirus types by DNA chip in Korean women: comparison with cytologic diagnosis.

OBJECTIVE: More sensitive and reliable methods than individual testing (such as polymerase chain reaction, restriction fragment length polymorphism, and Southern blot) should be developed as screening tools for the detection of latent human papillomavirus. Today, the new Bethesda system recommends human papillomavirus testing as an adjuvant to the conventional Papanicolaou smear for more comprehensive identification of women at certain risk of cervical neoplasia. We performed human papillomavirus genotyping with the newly designed human papillomavirus DNA chip, which is based on polymerase chain reaction for high-throughput screening power, and compared the results with the results of a Papanicolaou smear according to the new Bethesda system. STUDY DESIGN: Polymerase chain reaction amplifications of the human papillomavirus L1 region from biologic samples were hybridized to silanized glass slides by a microarrayer, which comprised 22 specific oligonucleotide probes to their genotypes, consisting of 15 high-risk and 7 low-risk types. Two cervical cancer cell lines and 20 plasmids that contained each type of the human papillomavirus whole genome were used for the evaluation of this method; in all cases, the cancer cell lines and plasmids showed clear positive signals on their corresponding positions. A comparative study that used 685 cervicovaginal swabs was performed by human papillomavirus DNA chip microarray together with Papanicolaou diagnosis. RESULTS: Human papillomavirus was identified as positive in 31.9% of the 414 control samples and in 78.6% of the 271 neoplastic lesions. The major prevailing human papillomavirus genotypes were human papillomavirus types 16, 58, and 18, in descending order of incidence (average overall, 78.8%). Almost all of the remaining cases were comprised of human papillomavirus types 39, 52, 56, and 51. The frequency of multiple infection of human papillomavirus was highest in low-grade squamous intraepithelial lesion but was lowest in squamous cell carcinoma. All cases that exhibited infection of single human papillomavirus type 58 were squamous cell carcinoma. CONCLUSION: Human papillomavirus types 16, 18, and 58 were confirmed to be major causative factors for cervical carcinogenesis. Low-grade squamous intraepithelial lesion is a heterogeneous entity that is composed of different human papillomavirus subtypes and prevails in younger women (<40 years old). The human papillomavirus chip has potential use as a high-throughput screening test.

Adult↗

PubMed2003

Overexpression of cyclooxygenase-2 is associated with breast carcinoma and its poor prognostic factors.

Cyclooxygenase is the rate-limiting enzyme that catalyzes the conversion of arachidonic acid to prostaglandins. The inducible form, cyclooxygenase-2, is known to be overexpressed in various human cancers including the colon, stomach, and urinary bladder. In this study, we evaluated the overexpression of cyclooxygenase-2 in 64 cases of breast cancer and correlated the results with clinicopathologic parameters. Immunohistochemical staining for cyclooxygenase-2 demonstrated positivity of the tumor cells in 46 of 64 cases (72%). Cyclooxygenase-2 overexpression was significantly correlated with larger tumor size and advanced clinical stage. Cyclooxygenase-2 overexpression tended to be more frequently observed in cases with presence of lymph node metastasis and in cases without expression of estrogen and progesterone; however, there was no significant correlation statistically. Nuclear and histologic grade were not well correlated with cyclooxygenase-2 overexpression. When ductal carcinoma in situ was considered separately, 32 of 42 cases (76%) were positive for cyclooxygenase-2. We conclude that cyclooxygenase-2 is up-regulated in a high proportion of breast cancers. The overexpression of cyclooxygenase-2 was associated with larger tumor size and advanced clinical stage, although lymph node status, estrogen and progesterone expression, and nuclear and histologic grade were not significantly correlated. Therefore, cyclooxygenase-2 overexpression may be a feature of the aggressive phenotype and may be useful as a prognostic indicator in breast cancer.

Breast Neoplasms↗

PubMedDate not supplied

Altered expression of the DNA repair protein, N-methylpurine-DNA glycosylase (MPG) in human gonads.

BACKGROUND: The multifunctional mammalian MPG is responsible for a damaged DNA base in the nucleus. The DNA repair enzyme is transported from the cytoplasm to nucleus to repair the DNA base when it is damaged. If the enzyme does not work properly, the damaged DNA may lead to carcinogenesis, cell death, aging or infertility. MATERIALS AND METHODS: This study was performed to determine mRNA expression and intracellular localization of the DNA repair protein, N-methylpurine-DNA glycosylase (MPG), in human ovary and testicular tissues, particularly in epithelial ovarian tumor and spermatogenic (maturation) arrest infertile patients, by RT-PCR and immunohistochemical staining using human MPG monoclonal antibody. RESULTS: MPG mRNA expression in epithelial ovarian tumor and spermatogenic arrest testis tissues was slightly higher than in normal ovarian and testicular tissues, respectively. The present study demonstrated new and unexpected patterns of cellular and subcellular localization of this enzyme. In a normal ovary, immunostaining for MPG was observed in the nucleus of oocyte, granulosa and stromal cells. MPG was stained mostly in the nucleus and faintly-stained in the cytoplasm of normal coelomic epithelium as well as in benign epithelial ovarian tumors. However, the MPG expression of the nucleus in malignant epithelial tumors, both serous and mucinous type, disappeared. The spermatocyte and Leydig cells in normal testis were immunostained only in the cytoplasm. The spermatocyte and Leydig cells in spermatogenic arrest testis tissues showed up both in the nucleus and cytoplasm. The subcellular localization of MPG in the tissues tested was heterogeneous, while the altered MPG expression was found in ovarian tumor and spermatogenic arrest testis. CONCLUSION: These results suggest MPG's role in human gonadal tissues and raise the possibility that the altered mRNA level and intracellular localization could be associated with ovarian tumorigenesis and male infertility.

Cytoplasm↗

PubMedDate not supplied

Expression of the DNA repair enzyme, N-methylpurine-DNA glycosylase (MPG) in astrocytic tumors.

BACKGROUND: DNA is continuously damaged due to exposure to alkylating compounds or oxygen free radicals generated during normal cellular metabolism as well as to environmental mutagens. Several studies have shown that N-methylpurine-DNA-glycosylase (MPG) mRNA levels were lower in adult brain than in other tissues. Terminally differentiated and nonproliferating cells have a lower DNA repair capacity than proliferating cells from various organs, embryo, ovary and testis. If the DNA repair are not efficient, the damaged DNA may lead to tumorigenesis or cell death. This study was designed to investigate the association of tumorigenesis with MPG in astrocytic tumors. MATERIALS AND METHODS: MPG mRNA expression and localization in astrocytic tumors and tumor-adjacent brain tissues was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and RNA in situ hybridization. The expression and intracellular localization of MPG protein was determined by immunohistochemistry. RESULTS: MPG mRNA expression in RT-PCR was slightly higher in astrocytic tumor tissues than in brain tissues adjacent to tumor and in astrocytic tumor tissues, regardless of the tumor grades. MPG protein localization in immunohistochemical study was detected only in the nucleus of all tumor tissues. Interestingly, in brain tissues adjacent to tumor, immunohistochemical staining for MPG was not observed either in the nucleus or the cytoplasm. However, we could not detect MPG protein in the brain tissues adjacent to the tumor although MPG mRNA was detected in the tissues. CONCLUSION: These results suggest an MPG's role in human astrocytic tumors and raise the possibility that the altered MPG expression and intracellular localization could be associated with astrocytic tumorigenesis.

Astrocytoma↗

PubMedDate not supplied

IMUP-1 and IMUP-2 genes are up-regulated in human ovarian epithelial tumors.

BACKGROUND: Normal cells lose their ability to divide after a finite number of cell divisions. Under the influence of Simian virus 40 (SV 40) large T-antigen, which interacts with the cell cycle regulators p53 and pRb, cells enter a phase of an extended pre-immortalized cells. Immortalization-up-regulated protein 1 (IMUP-1) and immortalization-up-regulated protein 2 (IMUP-2) genes have been recently cloned and are known to be involved in SV40-mediated immortalization. However, the roles of IMUP-1 and IMUP-2 are not known in human ovarian epithelial tumors. PATIENTS AND METHODS: This study was performed to determine mRNA expression and intracellular localization of the IMUP-1 and IMUP-2 in ovarian epithelial tumors by RT-PCR and immunohistochemical staining using human IMUP-1 and IMUP-2 monoclonal antibodies. RESULTS: IMUP-1 (4.0-fold) and IMUP-2 (2.4-fold) mRNA expression in ovarian epithelial tumors were significantly higher than in normal ovarian tissues (p < 0.05). The mRNAs of IMUP-1 and IMUP-2 in the ovarian cancer cell lines were about 4.9- and 2.9-fold compared to the normal ovarian cell line, respectively. The subcellular expression of these two proteins in immunohistochemical stains was detected mainly in the nucleus of tumor cells, whereas adjacent normal ovarian stromal cells were faintly or negatively stained with these proteins. However, the staining intensity of IMUP-1 and IMUP-2 in ovarian epithelial tumors were not different between histological types or grades. CONCLUSION: These results showed the up-regulation of IMUP-1 and IMUP-2 in human ovarian epithelial tumors and suggested that the altered mRNA level of these molecules is possibly associated with ovarian tumorigenesis.

Carcinoma↗