Project description:Background: Germline polymorphisms can influence gene expression networks in normal mammalian tissues and can affect disease susceptibility. We and others have shown that analysis of this genetic architecture can identify single genes and whole pathways that influence complex traits including inflammation and cancer susceptibility. Whether germline variants affect gene expression in tumors which have undergone somatic alterations, and the extent to which these variants influence tumor progression, is unknown. Results: Using an integrated linkage and genomic analysis of a mouse model of skin cancer that produces both benign tumors and malignant carcinomas, we document major changes in germline control of gene expression during skin tumor development resulting from cell selection, somatic genetic events, and changes in the tumor microenvironment. The number of significant expression Quantitative Trait Loci (eQTLs) is progressively reduced in benign and malignant skin tumors when compared to normal skin. However, novel tumor-specific eQTLs are detected for several genes associated with tumor susceptibility, including Interleukin 18, Granzyme E, Sprouty homolog 2, and MAP kinase kinase 4. Conclusions: We conclude that the genetic architecture is substantially altered in tumors, and that eQTL analysis of tumors can identify host factors that influence the tumor microenvironment, MAP kinase signaling, and cancer susceptibility.
Project description:Background: Most skin-related traits have been studied in Caucasian genetic backgrounds. A comprehensive study on skin-associated genetic effects on underrepresented populations such as Vietnam is needed to fill the gaps in the field. Objectives: We aimed to develop a computational pipeline to predict the effect of genetic factors on skin traits using public data (GWAS catalogs and whole-genome sequencing (WGS) data from the 1000 Genomes Project-1KGP) and in-house Vietnamese data (WGS and genotyping by SNP array). Also, we compared the genetic predispositions of 25 skin-related traits of Vietnamese population to others to acquire population-specific insights regarding skin health. Results: The skin-related genetic profile of Vietnamese cohorts was similar at most to East Asian cohorts (JPT: Fst=0.036, CHB: Fst=0.031, CHS: Fst=0.027, CDX: Fst=0.025) in the population study. In addition, we identified pairs of skin traits at high risk of frequent co-occurrence (such as skin aging and wrinkles (r = 0.45, p =1.50e-5) or collagen degradation and moisturizing (r = 0.35, p = 1.1e-3)).
Project description:Germline polymorphisms influence gene expression networks in normal mammalian tissues. Analysis of this genetic architecture can identify single genes and whole pathways that influence to complex traits including inflammation and cancer susceptibility. Changes in the genetic architecture during the development of benign and malignant tumours have not been investigated. Here, we document major changes in germline control of gene expression during skin tumour development as a consequence of cell selection, somatic genetic events, and changes in tumour microenvironment. Immune response genes such as Interleukin 18 and Granzyme E are under germline control in tumours but not in normal skin. Gene expression networks linked to tumour susceptibility and hair follicle stem cell markers in normal skin undergo significant reorganization during tumour progression. Our data highlight opposing roles of Interleukin-1 signaling networks in tumour susceptibility and tumour progression and have implications for the development of chemopreventive strategies to reduce cancer incidence. Skin tumors were induced on dorsal back skin from a Mus spretus / Mus musculus backcross ([SPRET/Ei X FVB/N] X FVB/N) mice by treatment of dorsal back skin with dimethyl benzanthracene (DMBA) and tetradecanoyl-phorbol acetate (TPA). This treatment induced multiple benign papillomas as well as malignant squamous cell carcinomas (SCC) and spindle cell carcinomas. Gene expression analysis was performed on mRNA extracted from 68 papillomas: two papillomas from each of 31 FVBBX mice and a single papilloma from six additional FVBBX mice. Papillomas were harvested when mice were sacrificed due to presence of a carcinoma or termination of the experiment.
Project description:Germline polymorphisms influence gene expression networks in normal mammalian tissues. Analysis of this genetic architecture can identify single genes and whole pathways that influence to complex traits including inflammation and cancer susceptibility. Changes in the genetic architecture during the development of benign and malignant tumours have not been investigated. Here, we document major changes in germline control of gene expression during skin tumour development as a consequence of cell selection, somatic genetic events, and changes in tumour microenvironment. Immune response genes such as Interleukin 18 and Granzyme E are under germline control in tumours but not in normal skin. Gene expression networks linked to tumour susceptibility and hair follicle stem cell markers in normal skin undergo significant reorganization during tumour progression. Our data highlight opposing roles of Interleukin-1 signaling networks in tumour susceptibility and tumour progression and have implications for the development of chemopreventive strategies to reduce cancer incidence. Skin tumors were induced on dorsal back skin from a Mus spretus / Mus musculus backcross ([SPRET/Ei X FVB/N] X FVB/N) mice by treatment of dorsal back skin with dimethyl benzanthracene (DMBA) and tetradecanoyl-phorbol acetate (TPA). This treatment induced multiple benign papillomas as well as malignant squamous cell carcinomas (SCC) and spindle cell carcinomas. 60 carcinomas were harvested from 55 mice; five mice provided two carcinomas each.
Project description:Background: Germline polymorphisms can influence gene expression networks in normal mammalian tissues and can affect disease susceptibility. We and others have shown that analysis of this genetic architecture can identify single genes and whole pathways that influence complex traits including inflammation and cancer susceptibility. Whether germline variants affect gene expression in tumors which have undergone somatic alterations, and the extent to which these variants influence tumor progression, is unknown. Results: Using an integrated linkage and genomic analysis of a mouse model of skin cancer that produces both benign tumors and malignant carcinomas, we document major changes in germline control of gene expression during skin tumor development resulting from cell selection, somatic genetic events, and changes in the tumor microenvironment. The number of significant expression Quantitative Trait Loci (eQTLs) is progressively reduced in benign and malignant skin tumors when compared to normal skin. However, novel tumor-specific eQTLs are detected for several genes associated with tumor susceptibility, including Interleukin 18, Granzyme E, Sprouty homolog 2, and MAP kinase kinase 4. Conclusions: We conclude that the genetic architecture is substantially altered in tumors, and that eQTL analysis of tumors can identify host factors that influence the tumor microenvironment, MAP kinase signaling, and cancer susceptibility. A backcross was generated using male Mus spretus and female FVB/N mice; female F1 hybrids were mated with male FVB/N mice. Backcross mice (8-12 weeks old) received a single dose of DMBA (25 µg per mouse in 200 µl acetone). Starting one week after the initiation tumors were promoted with TPA (200 µl of 10-4 M solution in acetone) twice weekly for 20 weeks. Initiation and promotion were performed on doral back skin. DNA from 62 Carcinomas and matched untreated tails (used for normal DNA comparison) was obtained from tissue that was snap frozen when animals were sacrificed.
Project description:Germline polymorphisms influence gene expression networks in normal mammalian tissues. Analysis of this genetic architecture can identify single genes and whole pathways that influence to complex traits including inflammation and cancer susceptibility. Changes in the genetic architecture during the development of benign and malignant tumours have not been investigated. Here, we document major changes in germline control of gene expression during skin tumour development as a consequence of cell selection, somatic genetic events, and changes in tumour microenvironment. Immune response genes such as Interleukin 18 and Granzyme E are under germline control in tumours but not in normal skin. Gene expression networks linked to tumour susceptibility and hair follicle stem cell markers in normal skin undergo significant reorganization during tumour progression. Our data highlight opposing roles of Interleukin-1 signaling networks in tumour susceptibility and tumour progression and have implications for the development of chemopreventive strategies to reduce cancer incidence.
Project description:Germline polymorphisms influence gene expression networks in normal mammalian tissues. Analysis of this genetic architecture can identify single genes and whole pathways that influence to complex traits including inflammation and cancer susceptibility. Changes in the genetic architecture during the development of benign and malignant tumours have not been investigated. Here, we document major changes in germline control of gene expression during skin tumour development as a consequence of cell selection, somatic genetic events, and changes in tumour microenvironment. Immune response genes such as Interleukin 18 and Granzyme E are under germline control in tumours but not in normal skin. Gene expression networks linked to tumour susceptibility and hair follicle stem cell markers in normal skin undergo significant reorganization during tumour progression. Our data highlight opposing roles of Interleukin-1 signaling networks in tumour susceptibility and tumour progression and have implications for the development of chemopreventive strategies to reduce cancer incidence.
Project description:Whole skin DNA methylation variation has been implicated in several diseases, including melanoma, but its genetic basis has not yet been characterised. Using bulk skin tissue samples from 414 healthy female UK twins, we performed twin-based heritability and methylation Quantitative Trait Loci (meQTL) analyses for >400,000 DNA methylation sites. We find that the human skin DNA methylome is on average less heritable than previously estimated in blood and other tissues (mean heritability: 10.02%). MeQTL analysis identified local genetic effects influencing DNA methylation at 18.8% (76,442) of tested CpG sites, as well as 1,775 CpG sites associated with at least one distal genetic variant. As a functional follow-up we performed skin expression QTL (eQTL) analyses in a partially overlapping sample of 604 female twins. Colocalisation analysis identified over 3,500 shared genetic effects affecting thousands of CpG sites (10,067) and genes (4,475). Mediation analysis of putative colocalised gene-CpG pairs identified 114 genes with evidence for eQTL effects being mediated by DNA methylation in skin, including in genes implicated skin disease such as ALOX12 and CSPG4. We further explored the relevance of skin meQTLs to skin disease, and found that skin meQTLs and CpGs under genetic influence were enriched for multiple skin-related genome-wide and epigenome-wide association signals, including for melanoma and psoriasis. Our findings give insights into the regulatory landscape of epigenomic variation in skin.
Project description:Gene expression in self-renewing epithelial tissues is controlled by cis- and trans-activating regulatory factors that mediate responses to exogenous agents capable of causing tissue damage, infection, inflammation, or tumorigenesis. We used network construction methods to analyze the genetic architecture of gene expression in normal mouse skin in a cross between tumor-susceptible Mus musculus and tumor-resistant Mus spretus. We demonstrate that gene expression motifs representing different constituent cell types within the skin such as hair follicle cells, haematopoietic cells, and melanocytes are under separate genetic control. Motifs associated with inflammation, epidermal barrier function and proliferation are differentially regulated in mice susceptible or resistant to tumor development. The intestinal stem cell marker Lgr5 is identified as a candidate master regulator of hair follicle gene expression, and the Vitamin D receptor (Vdr) links epidermal barrier function, inflammation, and tumor susceptibility. Keywords: Expression Quantitative Trait Loci A backcross was generated using male Mus spretus and female FVB/N mice; female F1 hybrids were mated with male FVB/N mice. Seventy-one backcross mice (8-12 weeks old) received a single dose of DMBA (25 µg per mouse in 200 µl acetone). Starting one week after the initiation tumors were promoted with TPA (200 µl of 10-4 M solution in acetone) twice weekly for 20 weeks. Initiation and promotion were performed on doral back skin. Normal tail skin was snap frozen when the animals were sacrificed. Tail epidermis from completely untreated Spretus, FVB, and Spretus x FVB F1 mice was also analyzed.