Epigenetic memory in induced pluripotent stem cells.

Somatic cell nuclear transfer and transcription-factor-based reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Through different mechanisms and kinetics, these two reprogramming methods reset genomic methylation, an epigenetic modification of DNA that influences gene expression, leading us to hypothesize that the resulting pluripotent stem cells might have different properties. Here we observe that low-passage induced pluripotent stem cells (iPSCs) derived by factor-based reprogramming of adult murine tissues harbour residual DNA methylation signatures characteristic of their somatic tissue of origin, which favours their differentiation along lineages related to the donor cell, while restricting alternative cell fates. Such an 'epigenetic memory' of the donor tissue could be reset by differentiation and serial reprogramming, or by treatment of iPSCs with chromatin-modifying drugs. In contrast, the differentiation and methylation of nuclear-transfer-derived pluripotent stem cells were more similar to classical embryonic stem cells than were iPSCs. Our data indicate that nuclear transfer is more effective at establishing the ground state of pluripotency than factor-based reprogramming, which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment.

Clinical characteristics and risk of melanoma development from giant congenital melanocytic naevi in Korea: a nationwide retrospective study.

BACKGROUND: Giant congenital melanocytic naevi (GCMN) are known risk factors for the development of melanoma. However, melanoma risk among Asians is rarely evaluated. OBJECTIVES: To evaluate the clinical characteristics and risk of melanoma development from GCMN in Koreans, we performed a nationwide retrospective cohort study in Korea. GCMN were defined as those comprising ≥5% body surface area in children or measuring ≥20cm in adults. METHODS: In total, 131 patients with GCMN were enrolled, with a mean age of 10·3years (range: birth-70years). RESULTS: The posterior trunk was the most common site (67, 51·1%), followed by lateral trunk, anterior trunk, legs, both anterior and posterior trunk, buttocks, and arms. Satellite naevi were present in 69 cases (52·7%), and axial areas were more commonly involved in patients with satellite naevi than in those without satellite lesions. Atypical features such as rete ridge elongation and bridges were seen, and, among these, pagetoid spread and ballooning cell changes were more common in patients <4years old. Proliferative nodules were found in three cases. Melanomas had developed in three of 131 patients (2·3%; a 6-year-old girl, a 14-year-old girl and a 70-year-old man), and the incidence rate was 990 per 100000 person-years. Melanomas in these three patients consisted of two cutaneous melanomas and one extracutaneous meningeal melanoma. CONCLUSIONS: We should be aware of melanoma development from GCMN, and lifelong follow-up is required due to the risk of melanoma arising in GCMN.

Hair greying is associated with active hair growth.

BACKGROUND: Hair greying is an obvious sign of ageing in humans. White (nonpigmented) hair is thicker than black (pigmented) hair. The growth rate of white hair is also significantly higher than that of black hair. However, the mechanism underlying this is largely unknown. OBJECTIVES: To examine the association between hair greying and hair growth patterns by evaluating expression of the genes or proteins related to hair growth in white and black hairs. METHODS: Morphological characteristics were observed in eyebrow and scalp hairs. The differential expression of genes was analysed in black and white hairs from human scalp by a microarray analysis. Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry for genes and proteins related to hair growth were performed in black and white hairs. RESULTS: Keratin and keratin-associated protein (KRTAP) genes in white hair were upregulated at least two-fold in comparison with black hair in a microarray analysis. Upregulation of selected keratin genes and KRTAP4 isoform genes in white hair was validated by RT-PCR. Immunoreactivity for KRT6, KRT14/16 and KRT25 was increased in the hair follicle of white hair compared with black hair. Gene expression of fibroblast growth factor 5 (FGF5) was downregulated in white hair compared with black hair. However, gene expression of FGF7 was upregulated in white hair compared with black hair. CONCLUSIONS: Expression of genes and proteins associated with active hair growth is upregulated in white (nonpigmented) hair compared with black (pigmented) hair. These results suggest that hair greying is associated with active hair growth.

Callus formation is associated with hyperproliferation and incomplete differentiation of keratinocytes, and increased expression of adhesion molecules.

BACKGROUND: A callus is a local thickening of skin, characterized by accelerated keratinization and a reduced rate of desquamation. However, the mechanism of callus formation is not fully understood. OBJECTIVES: To evaluate the expression patterns, in callused skin, of genes that are implicated in keratinization and adhesion/desquamation. METHODS: Samples of skin from the dorsum of the foot (DF), centre of the plantar arch (CP) and anterior aspect of the heel (AH) were obtained from fresh cadavers, and protein and gene expression were determined by immunohistochemistry and reverse transcription-polymerase chain reaction, respectively. RESULTS: The stratum corneum in the DF showed a splitting phenotype by conventional haematoxylin and eosin staining, while the stratum corneum was normal in the AH. Cells of the stratum corneum in the AH were nonsquamous. Expression of cornification-related molecules including involucrin, filaggrin, caspase 14 and calcium-sensing receptor was higher in the AH. Similarly, expression of adhesive proteins such as corneodesmosin, desmoglein 1 and desmocollin 1 was increased in the AH. However, protease-activated receptor 2 expression was reduced in the stratum granulosum in the AH. The number of proliferating cells in the stratum basale was significantly increased in the AH, compared with the DF and CP. CONCLUSIONS: Our data suggest that calluses form as a result of hyperproliferation and incomplete differentiation of epidermal keratinocytes, and increased expression of adhesion molecules.

Inhibitory effect of Korean mistletoe (Viscum album coloratum) extract on tumour angiogenesis and metastasis of haematogenous and non-haematogenous tumour cells in mice.

We examined the inhibitory effect of an aqueous extract (referred to as KM-110) from Viscum album coloratum, a Korean mistletoe, on tumour metastasis produced by highly metastatic murine tumour cells, B16-BL6 melanoma, colon 26-M3.1 carcinoma and L5178Y-ML25 lymphoma cells, using experimental and spontaneous metastasis models in syngeneic mice. In experimental metastasis of B16-BL6 and colon 26-M3.1 cells, intravenous (i.v.) administration of KM-110 (100 micrograms/mouse) 1 day after tumour inoculation significantly inhibited lung metastasis of both tumour cells. The administration of KM-110 also exhibited a therapeutic effect on liver and spleen metastasis of L5178Y-ML25 lymphoma cells. Furthermore, in spontaneous metastasis of B16-BL6 melanoma cells, multiple administration of KM-110 into tumour-bearing mice resulted in significant inhibition of lung metastasis by tumour cells, as well as the suppressive activity to the growth of primary tumour. In in vivo analysis for tumour-induced angiogenesis, the i.v. administration of KM-110 suppressed tumour growth and inhibited the number of blood vessels oriented towards the tumour mass. In a bioassay, the culture supernatant (KM-110-treated medium) of murine peritoneal macrophages that had been stimulated with KM-110 (1-10 micrograms/ml) for 30 min followed by 24 h incubation in fresh medium showed a strong tumour necrosis factor-alpha (TNF-alpha) activity. In addition, KM-110-treated medium significantly inhibited the growth of in vitro cultures of rat lung endothelial (RLE) cells. These results suggested that the extract of Korean mistletoe inhibits tumour metastasis caused by haematogenous as well as non-haematogenous tumour cells, and that its antimetastatic effect results from the suppression of tumour growth and the inhibition of tumour-induced angiogenesis by inducing TNF-alpha.

Antitumor activities of a newly synthesized shikonin derivative, 2-hyim-DMNQ-S-33.

2- or 6-(1-hydroxyiminoalkyl)-5,8-dimethoxy-1, 4-naphthoquinone(2- or 6-hyim-DMNQ) derived from the roots of Lithospermum erythrorhizon was synthesized for the evaluation of antitumor activities. Among those derivatives, 2-hyim-DMNQ-S33 was found to be a potent anticancer agent. This compound suppressed the proliferation of Radiation Induced Fibrosarcoma (RIF) cells in a dose-dependent manner. 2-hyim-DMNQ-S33 significantly prolonged the survival time by 239% as compared with Sarcoma 180 tumor-bearing control mice in vivo. We found that the compound significantly suppressed phosphorylation of extracellular signal-regulated kinase (pERK) and activated c-jun-N-terminal kinase (JNK) and protein kinase C (PKC)-alpha following 4 h-treatment. These findings indicate that 2-hyim-DMSQ-S33 exerts antitumor activities by regulating pERK, JNK and PKC-alpha.

Lectins isolated from Korean mistletoe (Viscum album coloratum) induce apoptosis in tumor cells.

Cytotoxic lectins (KML-C) were isolated from an extract of Korean mistletoe [Viscum album C. (coloratum)] by affinity chromatography on a hydrolysed Sepharose 4B column, and the chemical and biological properties of KML-C were examined, partly by comparing them with a lectin (EML-1) from European mistletoe[Viscum album L. (loranthaceae)]. The hemagglutinating activity of KML-C was inhibited by N-acetyl-D-galactosamine and D-galactose at the minimum concentrations of 6.3 and 12.5 microM/ml, respectively. Further biochemical analyses indicated that KML-C consists of four chains (Mr = 27.5, 30, 31 and 32.5 kDa) which, in some of the molecules, are disulfide-linked, and that the chains of KML-C are distributed over a broad range of isoelectric points (pI), 8.0 to 9.0, whereas the range for EML-1 is 6.6-7.0. A difference was also observed between the N-terminal sequences of KML-C and EML-1. The isolated lectins showed strong cytotoxicity against various human and murine tumor cells, and the cytotoxic activity of KML-C was higher than that of EML-1. Tumor cells treated with KML-C exhibited typical patterns of apoptotic cell death, such as apparent morphological changes and DNA fragmentation, and its apoptosis-inducing activity was blocked by addition of Zn2+, an inhibitor of Ca2+/Mg2+ -dependent endonucleases, in a dose-dependent manner. These results suggest that KML-C is a novel lectin related to the cytotoxicity of Korean mistletoe, and that its cytotoxic activity against tumor cells is due to apoptosis mediated by Ca2+/Mg2+ -dependent endonucleases.

Induction of uncoupling protein-2 (UCP2) gene expression on the differentiation of rat preadipocytes to adipocytes in primary culture.

We have examined uncoupling protein-2 (UCP2) gene expression in the adipose tissue of obese and normal rats and mice, and also in differentiated rat adipocytes in primary culture. Expression of the UCP2 gene was examined in rat and mouse adipose tissues using both RT-PCR and Northern blotting. Although the RT-PCR was not quantitative, the band corresponding to the UCP2 mRNA was stronger in white adipose tissue than in brown fat, regardless of the body weight of the rats. In agreement with the RT-PCR data, there was a higher level of UCP2 mRNA in the white adipocytes than in brown adipocytes, the level being greater in obese mice. Fibroblastic preadipocytes were obtained from the inguinal fat pad of suckling rats. Lipid droplets developed inside the cells upon differentiation and adipsin and UCP2 mRNAs were detected by Northern blotting. Both mRNAs were evident in the adipocytes at 4, 6, and 10 d after the induction of differentiation. There was no indication that the expression of UCP2 was markedly affected by the addition of leptin, dexamethasone or isoprenaline.

cDNA cloning and sequence analysis of the lectin genes of the Korean mistletoe (Viscum album coloratum).

We previously isolated a lectin of the Korean mistletoe (Viscum album coloratum). The cDNA clones that encode the A- or the B-chain of the Korean mistletoe lectin were cloned by reverse transcriptase polymerase chain reaction (RT-PCR). The mRNAs that were extracted from the Korean mistletoe were amplified, ligated into the pGEM-T easy vector, and screened with a Korean mistletoe lectin-specific probe. The probe was prepared by PCR amplification of the Korean mistletoe DNA using a primer set designed on the basis of amino acid sequences of the Korean mistletoe lectin that we had purified and reported. Unlike a recent report, which states that the European mistletoe lectin gene has no isoforms, several different clones of the A- and B-chains of the Korean mistletoe lectin were cloned from the same primer set. Three clones of each were selected for sequencing. The sizes of the A-chains were 762, 762, and 768 bp, respectively. The B-chain sizes were 798, 789, and 789 bp, respectively. Each of the clones showed significant variation in the amino acids sequence, including the N-linked glycosylation sites of the lectin. The sequence analysis of each of the Korean lectin clones, in comparison with the European mistletoe lectin and the other type II ribosome binding proteins, is discussed in the text. In addition, Southern blot analysis of the Korean mistletoe genomic DNA, restricted by different enzymes and hybridized with the lectin DNA, showed multi-bands, supporting the existence of multicopy genes or a gene family. These data suggest that heterogeneity of the mistletoe lectin is not only introduced by post-translational modifications, but also by expression of isotypes of the lectin genes.

Cellular and humoral adjuvant activity of lectins isolated from Korean mistletoe (Viscum album colaratum).

The adjuvant effect of lectins (KML-C) isolated from Korean mistletoe (Viscum album coloratum) on induction of humoral and cellular immune responses against keyhole limpet hemocyanine (KLH) was examined. When mice were immunized subcutaneously (s.c.) with KLH (20 micrograms/mouse) admixed with or without 50 ng/mouse of KML-C (KLH + KML-C), mice immunized with KLH + KML-C showed significantly higher antibody titers against KLH than those immunized with KLH alone, showing the highest titer 5 weeks after immunization. Furthermore, boost immunization with KLH + KML-C at 2-week interval elicited much higher activity than single immunization to enhance antibody responses against KLH. The assay for determining isotypes of antibodies revealed that KML-C augmented KLH-specific antibody titers of IgG1, IgG2a and IgG2b. The culture supernatants obtained from the splenocytes of mice treated with KLH + KML-C also showed a higher level of both KLH-specific Th-1 (IL-2 and IFN-gamma) and Th-2 type cytokine (IL-4). In an in vitro analysis of T lymphocyte proliferation to KLH on week 4, the splenocytes of mice treated with KLH + KML-C showed a significantly higher proliferating activity than those treated with KLH alone. In addition, mice immunized twice with KLH + KML-C and followed by intrafootpad (i.f.) injection of KLH (50 micrograms/site) 14 weeks after the primary immunization induced a higher delayed-type hypersensitivity (DTH) reaction than mice treated with KLH alone. These results suggest that KML-C is a potent immunoadjuvant to enhance cellular and humoral immune responses.

Inhibition of tumor growth and metastasis by Korean mistletoe lectin is associated with apoptosis and antiangiogenesis.

The mistletoe lectins are major active components in the extract of European mistletoes that have been widely used in adjuvant chemotherapy of cancer. This study was performed to investigate the mechanism of anticancer and antimetastatic activity of the purified Korean mistletoe lectin (Viscum album L. coloratum agglutinin, VCA). C57BL6 mice inoculated with B16-BL6 melanoma cells and treated with VCA were assessed for survival and metastasis. The induction of apoptosis of B16-BL6 cells by VCA was investigated by morphological changes, DNA fragmentation characteristics, and cell cycle analysis. The antiangiogenic activity of VCA was also measured by the CAM (choriallantoic membrane) assay. Length of survival of mice was increased and lung metastasis was inhibited by VCA. Treatment of cells with VCA resulted in growth suppression, nuclear morphological changes, DNA fragmentation, and an increased fraction of cells in sub-G1 consistent with apoptosis. Antiangiogenesis of VCA was assessed by CAM assay, where vessel growth induced by fat emulsion was decreased. These results suggest that VCA inhibits tumor growth and metastasis by increasing apoptosis and inhibiting angiogenesis.

A case of estrogen dermatitis.

A 29-year-old Korean woman had erythematous papular patches on her face for six months. The eruptions recurred in a cyclic fashion along with her menstruation. The patient responded positively to an intradermal skin test for estrogen and showed marked improvement with the antiestrogen drug, Tamoxifen. We concluded that sensitivity to her own estrogen caused this dermatitis, that an intradermal skin test with progesterone and estrogen should be carried out routinely in patients with cyclic premenstrual flares, and that tamoxifen can be used as a specific therapy. To the best of our knowledge, this woman is the first patient with estrogen dermatitis reported in Korea.

Papular elastorrhexis in childhood improved by intralesional injections of triamcinolone.

Papular elastorrhexis is a rare disease developing asymptomatic skin-colored small papules in adolescence with histopathological loss of elastic fibers. There has been no established treatment for this disease. A 4-year-old Korean boy had multiple, hard, whitish papules on his chest and back for one year. Histopathologic examination revealed focal loss of elastic fibers in the dermis, and X-ray examination showed no bony abnormalities. His skin lesions were improved by intralesional injections of triamcinolone but recurred after four months.

Early stage onychomadesis presenting as painful swellings of proximal nail folds.

Two Korean men complained of painful erythematous swellings of the proximal nail folds. When we removed the overlying nail plates, we observed new ones growing under the old ones. These painful swellings disappeared after the affected nails were extracted. We found typical onychomadesis in another finger during the follow-up, suggesting that the initial condition marked the onset of onychomadesis. Because both patients had plaster casts removed recently and histories of trauma, it was hypothesized that trauma might be responsible for this peculiar condition.

Epidermal grafting after chemical epilation in the treatment of vitiligo.

BACKGROUND: Vitiligo on hairy areas like the scalp and eyebrows is frequently associated with leukotrichia and repigmentation by photochemotherapy is usually difficult because of a deficient melanocyte reservoir. Although epidermal grafting to supply melanocytes is very effective for stable vitiligo, hair growth inhibits successful transfer of melanocytes from grafted epidermis in dense hair-bearing regions. OBJECTIVE: To investigate the effectiveness of preoperative chemical epilation to improve the results of epidermal graft by suction blister on hairy areas. METHODS: Two patients who had vitiligo with leukotrichia on the face and scalp were treated with epidermal grafting using suction blister after chemical epilation. Two weeks after the graft they were treated with topical psolaren plus ultraviolet A (PUVA) therapy. RESULTS: Epidermal grafting was performed successfully, and successful repigmentation of the skin with significant improvement of leukotrichia was observed in each of two patients. CONCLUSION: Chemical epilation followed by epidermal grafting is a safe, easy, and effective treatment for vitiligo affecting hairy regions.

A case of bleomycin-induced scleroderma.

The association of exposure to bleomycin with the development of scleroderma-like cutaneous abnormalities has been reported. We experienced a case of scleroderma involving the hands, feet, and forearms after bleomycin chemotherapy. The present report supports the possible causal relation of bleomycin with scleroderma. Regarding the widespread use of bleomycin, this complication is thought to be under appreciated.

Pefloxacin and ciprofloxacin increase UVA-induced edema and immune suppression.

BACKGROUND: Quinolone antibiotics are popularly prescribed antibiotics because of their wide antibacterial spectrum and lowered bacterial resistance. Quinolone antibiotics are one of the well-known photosensitizers that induce phototoxicity. Their role in photocarcinogenesis has been suggested in some studies. MATERIAL AND METHODS: Mice were treated with two quinolone antibiotics (ciprofloxacin, which is less phototoxic, and pefloxacin, which is more phototoxic) to study the effect of the antibiotics on sunburn and immune suppression by ultraviolet A (UVA) irradiation. The effects of a combined treatment with UVA and these quinolone antibiotics were measured on back skin swellings, sunburn cell formations, depletion of epidermal Langerhans cells, and local and systemic suppression of contact hypersensitivity. RESULTS: Mice treated with both UVA and quinolone showed significantly increased back skin swellings and decreased epidermal Langerhans cells than mice treated with UVA only. Sunburn cells were increased significantly in mice treated with pefloxacin and 50 J/cm2 of UVA. Combination of pefloxacin and UVA suppressed local contact hypersensitivity significantly, but not systemic contact hypersensitivity. CONCLUSION: Phototoxic quinolones augmented the effect of UVA by increasing sunburn and apoptosis, depleting Langerhans cells and suppressing local immune response. By affecting apoptosis and immune suppression, they may facilitate photocarcinogenesis caused by UVA.

Prophylactic effect of Korean mistletoe (Viscum album coloratum) extract on tumor metastasis is mediated by enhancement of NK cell activity.

We here demonstrated the prophylactic effect of an extract (KM-110) from Viscum album coloratum, a Korean mistletoe, on tumor metastasis produced by highly metastatic tumor cells, colon 26-M3.1 carcinoma, B16-BL6 melanoma and L5178Y-ML25 lymphoma cells, using experimental models in mice. Intravenous (i.v.) administration of KM-110 (100 microg/mouse) 2 days before tumor inoculation significantly inhibited lung metastasis of B16-BL6 and colon 26-M3.1 cells, and liver and spleen metastasis of L5178Y-ML25 cells. The prophylactic effect of KM-110 on tumor metastasis was evident with various administration routes, i.e. subcutaneous, oral, intranasal as well as i.v., and was dependent upon the dose of KM-110 administered. Furthermore, mice given KM-110 (100 microg) 2 days before tumor inoculation showed significantly prolonged survival rates compared with the untreated mice. In a time course analysis of NK activity, i.v. administration of KM-110 (100 microg) significantly augmented NK cytotoxicity to Yac-a tumor cells from 1 to 3 days after KM-110 treatment. Furthermore, depletion NK cells by injection of rabbit anti-asialo GM1 serum completely abolished the inhibitory effect of KM-110 on lung metastasis of colon 26-M3.1 cells. These results suggest that KM-110 possesses immunopotentiating activity which enhances the host defense system against tumors, and that its prophylactic effect on tumor metastasis is mediated by NK cell activation.