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:This is a first-in-human multi-center study which will be conducted in advanced malignant solid tumors patients. The solid tumor type is limited to melanoma, colorectal, non-small-cell lung, and thyroid cancer with positive BRAF V600 mutation. This study is divided into three stages: Phase Ia: a dose-escalation phase of XP-102; Phase Ib: a dose-escalation and sample size expansion phase of XP-102 plus trametinib; Phase IIa: an expansion phase of XP-102 plus trametinib.
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:Nucleotide Excision Repair (NER) removes bulky DNA lesions, such as ultraviolet (UV) light-induced cyclobutane pyrimidine dimers (CPDs) by utilizing two subpathways: Transcription-Coupled NER (TC-NER) and Global Genomic NER (GG-NER). XPD is a DNA helicase in the transcription factor IIH (TFIIH) complex that is important for DNA unwinding and damage verification during NER. Germline mutations in XPD can lead to human genetic disorders, including Xeroderma Pigmentosum (XP) or XP in combination with Cockayne Syndrome (XP/CS). While XP and XP/CS mutations in XPD generally disrupt NER, it remains uncharacterized whether they impair TC-NER, GG-NER or both NER subpathways. Many XPD mutation sites are conserved from archaeal to eukaryotic species. To understand how XPD mutations affect DNA repair, we introduced two pairs of XP and XP/CS mutations into the chromosomal locations of the yeast RAD3 gene, a homolog of human XPD. Interestingly, we found that the two XP/CS point mutations rendered yeast cells extremely sensitive to UV light, while the two XP mutants exhibited mild UV sensitivity. Consistently, repair of CPDs in the genomic DNA was slower in the two XP/CS relative to the two XP mutants. Using CPD sequencing (CPD-seq 2.0), a genome-wide UV damage sequencing method, our data indicates that XP/CS mutations abrogated repair by both GG-NER and TC-NER in the yeast genome, while XP mutations impaired GG-NER but retained significant TC-NER activity. In human XP-D cell lines, we also found that XP/CS cells showed greater sensitivity to Illudin S, a DNA damaging agent triggering TC-NER repair. Our study suggests that the XP/CS mutations in RAD3 or XPD gene have more severe DNA repair defects, particularly in the TC-NER subpathway, which may contribute to the Cockayne Syndrome phenotypes of some XP-D patients.
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.
