Project description:Xeroderma Pigmentosum (XP) is a DNA repair disorder characterized by photosensitivity, resulting in occurrence of freckle-like pigmented maculae and depigmented maculae on sun-exposed areas. XP complementation group A (XP-A) is the most frequent type in Japan, and patients with XP-A present most severe cutaneous and neurological symptoms due to nucleotide excision repair deficiency. Here, we established induced pluripotent stem cells (iPSCs) derived from XP-A patients and successfully differentiated into melanocytes. To elucidate the pathophysiology of XP, we comprehensively analyzed the difference in gene expression between XP-A-iMCs and healthy-control-iPSC-derived melanocytes (HC-iMCs) 4 hours and 12 hours after irradiation with 30 J/m2 or 150 J/m2 of UV-B using microarray analysis.
Project description:XPA is required for Nucleotide Excision Repair system, which could function to repair DNA damage induced by the UV. UV damage on the genomic DNA cannot be removed, thus persistence of damage could affect the transcriptional machinary. We used the microarray to investigate the global expression profiles in the XP-A and XP-V cells in the low dose of UVC comparing with fibroblast from healthy person. Human primary fibroblasts were developed from the skin of healthy person and two XP patients (XP-A and XP-V). We evaluated global expression profiles comparing the UVC-exposed (0.5J/m2, 5J/m2) with non-exposed sample.
Project description:XPA is required for Nucleotide Excision Repair system, which could function to repair DNA damage induced by the UV. UV damage on the genomic DNA cannot be removed, thus persistence of damage could affect the transcriptional machinary. We used the microarray to investigate the global expression profiles in the XP-A and XP-V cells in the low dose of UVC comparing with fibroblast from healthy person.
Project description:Malignant melanoma might develop from melanocytic nevi in which the growth-arrested state has been broken. We analyzed the gene expression of young and senescent human melanocytes in culture. In this dataset we include the expression data of young and senescent human melanocytes.
Project description:Notch1 Activation Confers Transforming Properties to Primary Human Melanocytes and Promotes Human Melanoma Progression We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Human neonatal melanocytes and Notch transformed human neonatal melanocytes were selected for RNA extraction and hybridization on Illumina gene expression array chip. Expression intensities were calculated and normalized for each gene probed on the array for all hybridizations using illumina Beadstudio#3 software. Microarray analyses were subsequently performed in GeneSpring to aid in the identification of genes differentially-expressed between Notch-infected and control melanocytes that may be responsible for the phenotypic changes described in the NIC-infected cells.
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi.
Project description:Immortalized, amelanotic melanocytes isolted from skin of Balb/c express enzymatically-inactive tyrosinase due to a homozygous point mutation (TGT->TCT) in tyrosinase gene, resulting in a lack of melanin . To serve as a control cell line, pigmentation was restored in these cells by correcting the point mutation using an RNA-DNA oligonucleotide (kingly gift from Dr. Alexeev Y. Vitali). We used microarray to detail the effect of tyrosinase mutation on gene expression in normal versus mutant melanocytes.
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi. We used RNA-Seq to detail the global programme of gene expression in primary human melanocytes which were Uninfected and BRAF600V induced cells