KHG26792 Inhibits Melanin Synthesis in Mel-Ab Cells and a Skin Equivalent Model

The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy) methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyrosinase was not inhibited directly. KHG26792 activated extracellular signal-regulated kinase (ERK), whereas an ERK pathway inhibitor, PD98059, rescued KHG26792-induced hypopigmentation. These results suggest that KHG26792 decreases melanin production via ERK activation. Moreover, the hypopigmentary effects of KHG26792 were confirmed in a pigmented skin equivalent model using Cervi cornus Colla (deer antler glue), in which the color of the pigmented artificial skin became lighter after treatment with KHG26792. In summary, our findings suggest that KHG26792 is a novel skin whitening agent.

Mutation Analysis of Genes Related to Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract. Recent studies have revealed much of the biological and genetics underpinning GISTs. METHODS: KIT, PDGFRA, NF2 and GPHN mutations were examined by PCR-SSCP and DNA sequencing. Immunohistochemical analyses of CD117, CD34, SMA, S-100 and desmin were performed in 11 GISTs cases, and each tumor classified as being either very low, low, intermediate or high risk. RESULTS: Mutation in exon 11 of KIT was identified in 6 of the 11 GISTs, but mutations in exon 9, 13 and 17 of KIT were not detected. Three cases lacking KIT mutations showed PDGFRA mutations. No NF2 mutations were detected. GPHN gene mutation in exon 1 was identified in one case, which showed a simple point mutation in exon 11 of KIT. In a correlation between the mutation types and risk of aggressive behavior, four tumors involved multiple ( >2 codons) KIT mutations and one showed a point mutation of KIT plus a GPHN mutation were high risk, but one tumor with a point mutation of KIT showed a low risk. Three tumors having a PDGFRA mutation were of intermediate or very low risk. CONCLUSION: Mutations at exon 9, 13 or 17 of KIT and a NF2 mutation are considered rare in sporadic GIST. KIT and PDGFRA mutations appeared to be alternatives. A GPHN mutation occurring with a KIT mutation may be a secondary change in the pathogenesis of GIST, as the KIT mutation is a major event in GIST. KIT mutant GIST may have a poorer prognosis than PDGFRA mutant GIST.

The Effects of Bear Bile on the Expression of the p53 Protein in Cancer Cell Lines / 대한해부학회지

The effects of bear bile on the expression of the p53 protein in cancer cell lines were investigated by Western blot and RT-PCR methods. The p53 protein expression was increased after addition of bear bile in HaCaT, KUMA3, KUMA4 and KUMA6 cell lines that carried mutations n the p53 gene, but it is not ncreased n HCT116 and KUMA5 cell lines with the normal p53 gene as determined by Western blot method. The level of p53 mRNA was not altered in all cell lines after the treatment of bear bile as determined RT-PCR. These results indicate that the increment of the p53 protein after addition of bear bile was caused by increase in the protein stability but not by increase in protein synthesis. It can be concluded that bear bile affects positively only in the cell lines which have genetic variation of the p53 gene, and does not affect in the cell lines which have wild-type p53 gene, on the other hand.

Effect of Antisense TGF-beta1 Oligodeoxynucleotides in Streptozotocin-Induced Diabetic Rat Kidney

Transforming growth factor (TGF)-beta1 is an important fibrogenic factor that is involved in the pathogenesis of diabetic nephropathy. We evaluated the effect of circular antisense TGF-beta1 oligodeoxynucleotides (ODNs) on the TGF-beta1 expression in the rat mesangial cell culture and in streptozotocin (STZ)-induced diabetic rats. Circular antisense TGF-beta1 ODNs were found to be stable in rat serum, significantly decreasing TGF-beta1 mRNA expression compared with linear antisense ODNs in the rat mesangial cell culture. Circular antisense TGF-beta1 ODNs were introduced into the tail vein of normal rats using hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer method and were confirmed to be delivered effectively into the kidney, liver, lungs, and spleen. To inhibit the overexpression of TGF-beta1 in diabetic kidneys, we introduced circular antisense TGF-beta1 ODNs into the STZ-induced diabetic rats. On day 13 after circular antisense TGF-beta1 ODNs injection, TGF-beta1 mRNA and protein expression markedly decreased and urinary TGF-beta1 excretion rate also dropped in the circular antisense TGF-beta1 ODNs-treated diabetic rats. These results suggest that circular antisense TGF-beta1 ODNs may be a useful tool for developing new therapeutic application for progressive diabetic nephropathy.

The Property of p53 Gene in Cell Lines of Squamous Cell Carcinoma / 대한해부학회지

The mutation of p53 tumor suppressor gene is the most common genetic variation of primary malignant tumors. The occurrence, progression and reaction for medical management of cancers can be different according to the characteristics of p53 gene, even if they are same kinds of malignant tumors. In this study, the property of p53 gene in 4 kinds of squamous cell carcinoma cell lines were investigated by using immunocytochemistry, PCR-SSCP, sequencing and Western blot methods. As a result, p53 mutation detected in 3 kinds of squamous cell carcinoma cell lines. Namely, it is found that T in codon 176 changed to A, and G in codon 281 changed to A in KUMA3 cell lines; CC in codon 241 changed to TT in KUMA4 cell lines; G in codon 266 changed to T in KUMA6 cell lines. In single nucleotide polymorphism of codon 72 of p53 gene, the genetic variations are Arg/Pro heterozygote in KUMA3 and KUMA4 cell lines; Arg/Arg homozygote in KUMA5 cell lines; Pro/Pro homozygote in KUMA6 cell lines. These results will provide useful data for p53 gene researches of various squamous cell carcinomas.

Ultrastructural Changes and Expression of Transforming Growth Factor-beta1 in Tacrolimus- Induced Nephropathy / 대한이식학회지

PURPOSE: Tacrolimus (FK506) is a new potent immunosuppressive agent which has been used as a primary immunosuppressive agent and rescue therapy for refractory rejection in kidney transplantation. In vitro, on a molecular basis, tacrolimus is 10 to 100 times more potent than cyclosporine. Complications associated with tacrolimus are similar to those seen in cyclosporine, including nephrotoxicity. An early marker of tacrolimus-induced nephropathy is tubular vacuolization, whereas long-term administration of tacrolimus is associated with striped interstitial fibrosis and arteriolar hyalinosis. However, morphological changes and pathogenesis of fibrosis in chronic tacrolimus-induced nephropathy remain poorly understood. Transforming growth factor (TGF)-beta1 has been implicated in the fibrosis of a number of chronic diseases of the kidney and other organs. This study was designed to clarify the ultrastructural changes of tacrolimus-induced nephropathy, and to evaluate the relationship between tacrolimus- induced nephropathy and expression of TGF-beta1. METHODS: Male ICR mice received tacrolimus daily at a dose of 2.5 mg/kg by intraperitoneal route for 12 weeks and sacrified 1, 4, 8, 10, and 12 weeks after the initiation of the study, respectively. The kidneys were removed, the cortex is carefully dissected from the medulla, and the tissues are processed for evaluation by light microscopy, electron microscopy, immunohistochemistry and RT-PCR for RNA analysis. RESULTS: Characteristic histological changes of tacrolimus-induced nephropathy were peritubular capillary and intraglomerular capillary congestions, vacuolizations of the tubular epithelium, pericapillary focal fibrosis, and tubular atrophy. Tacrolimus- treated kidneys had a progressive increase in the expression of TGF-beta1, especially in the glomerular and interstitial capillary endothelial cells and atrophied tubular epithelial cells. TGF-beta1 mRNA is expressed persistently in tacrolimus- treated mice for 12 weeks. CONCLUSION: It can be concluded that TGF-beta1 may be involved in the fibrogenesis in the tacrolimus-induced nephropathy.

Detection of Epstein Barr Virus and HTLV-1 in Head and Neck Lymphomas / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Extranodal non-Hodgkin's lymphoma (NHL) of the head and neck (H & N) accounts for 10-20% of all cases of NHL. Despite their frequency, the cause of these lymphomas is still poorly understood. Recently, the role of viral origin in NHLs, including Epstein-Barr virus (EBV), as the main cause of sinonasal lymphomas of T/NK cell phenotype and HTLV-1 as a cause of acute T-cell lymphoma/leukemia has been well documented. We investigated the clinicopathologic findings, immunophenotypic profile, and status of EBV and HTLV-1 DNA of patients with H & N lymphoma. MATERIALS AND METHODS: Twenty-seven patients with NHL of H & N region were studied. There were 15 males and 12 females with the median age of 50 years. All patients were reclassified according to the Working formulation (WF) and REAL classificaton. EBV genome DNA and HTLV-1 RNA were surveyed by PCR assay using formalin-fixed and paraffin-embedded tissue blocks. RESULTS: The tonsil was the most commonly involved site (44.4%), followed by nasal cavity (18.5%), nasopharynx (18.5%) and orbit (7.4%). Immunophenotyping revealed 19 cases of B cell lineage, 7 cases of T cell lineage and one case of null cell type. Most of B-cell lymphomas were diffuse large cell lymphomas (58%). Tonsillar lymphomas were all B-cell origin. Four of the five nasal cavity lymphomas and one nasopharyngeal lymphoma showed an angiocentric T/NK cell phenotype with strong association with EBV. EBV genome was detected in 15 of 26 H & N NHLs (57.7%). Seven of 19 B-cell lymphomas (36.8%) and all T/NK or null cell type lymphomas were positive for FBV DNA. However, there was no HTLV-1 positive cases found. CONCLUSIONS: It could be concluded that the high incidence of EBV of angiocentric T/NK-cell lymphomas of the nasal cavity may indicate a probable role of EBV in the development of these lymphomas.

The Effect of Glucocorticosteroids on Eosinophil Apoptosis Primed by Cultured Nasal Polyp Epithelial Cell Supernatant / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Eosinophil infiltration into inflammatory site is a characteristic histological finding in patients with allergic rhinitis, bronchial asthma, and nasal polyps. The regulation of eosinophil survival and apoptosis may play a major role in tissue eosinophilia, and glucocorticosteroids (GCs) have been used therapeutically for nasal polyps. The purpose of this study is to investigate the effect of commonly used GCs on eosinophil survival and apoptosis primed by nasal polyp epithelial cells. MATERIALS AND METHODS: Peripheral blood eosinophils were incubated in increasing concentrations (10-10M) to GCs (triamcinolone, dexamethasone, budesonide, and fluticasone propionate) from January, 1990 to December, 1999 prior to the addition of human nasal polyp epithelial cell conditioned media (HECM). Eosinophil viability was measured with a MTS assay and apoptosis was analyzed with the caspase-3 staining. RESULTS: GCs suppressed the HECM induced prolongation of eosinophil survival with apoptotic change of cells from 2 days after incubation. Fluticasone propionate showed the strongest effects and triamcinolone showed the weakest effects. CONCLUSION: GCs may diminish eosinophilic infiltration into nasal polyp by decreasing eosinophil viability, and abrogate the promoting effect of nasal epithelial cells.