@article{dba03fcaaf254c24a0b4f04094e558ee,
title = "Genetic variation in IRF4 expression modulates growth characteristics, tyrosinase expression and interferon-gamma response in melanocytic cells",
abstract = "A SNP within intron4 of the interferon regulatory factor4 (IRF4) gene, rs12203592*C/T, has been independently associated with pigmentation and age-specific effects on naevus count in European-derived populations. We have characterized the cis-regulatory activity of this intronic region and using human foreskin-derived melanoblast strains, we have explored the correlation between IRF4 rs12203592 homozygous C/C and T/T genotypes with TYR enzyme activity, supporting its association with pigmentation traits. Further, higher IRF4 protein levels directed by the rs12203592*C allele were associated with increased basal proliferation but decreased cell viability following UVR, an etiological factor in melanoma development. Since UVR, and accompanying IFNγ-mediated inflammatory response, is associated with melanomagenesis, we evaluated its effects in the context of IRF4 status. Manipulation of IRF4 levels followed by IFNγ treatment revealed a subset of chemokines and immuno-evasive molecules that are sensitive to IRF4 expression level and genotype including CTLA4 and PD-L1.",
keywords = "interferon response, IRF4, melanocyte, melanoma, MITF, tyrosinase, UVR response",
author = "Yash Chhabra and Yong, \{Hilary X.L.\} and Fane, \{Mitchell E.\} and Arish Soogrim and Wen Lim and Mahiuddin, \{Dayana Nur\} and Kim, \{Reuben S.Q.\} and Melinda Ashcroft and Beatson, \{Scott A.\} and Ainger, \{Stephen A.\} and Smit, \{Darren J.\} and Kasturee Jagirdar and Walker, \{Graeme J.\} and Sturm, \{Richard A.\} and Smith, \{Aaron G.\}",
note = "Funding Information: MTT-based cell viability and DAPI-stained nuclei count were employed to investigate the growth characteristics of the primary strains. Five MB strains per genotype were seeded at the same number into 24-well plates after which cells were counted and assessed by MTT assay at days 1, 3 and 7 post-plating. MTT assay data for the MB strains is shown in Figures 3a and S2D, with pooled analysis revealing that the C/C homozygote variant strains were significantly more proliferative than T/T variant strains across all the time points (p < .01) (Figure 3a). This observation was supported by DAPI nuclei staining showing significantly higher proliferation at Day 3 and Day 7 post-seeding in C/C variant strains (Figures 3b and S3A). We further corroborated these findings by performing BrdU uptake assays comparing the C/C and T/T genotyped MB strains at Day 3 post-seeding. A significantly higher percentage of fluorescence was detected in C/C MB cell strains (p < .01) indicating a greater proportion of cells in S-phase or mitosis, during which BrdU gets incorporated (Figure 3c). Funding Information: The authors thank the TRI Microscopy Core facility for technical assistance with microscopy. M. Fane is a recipient of a University of Queensland APA PhD scholarship, and RAS is an Australian NHMRC Senior Research Fellow. This study was funded by NHMRC APP1083612, Centre of Research Excellence for the Study of Naevi APP1099021 and Cancer Council Queensland APP1081219. Publisher Copyright: {\textcopyright} 2017 John Wiley \& Sons A/S. Published by John Wiley \& Sons Ltd",
year = "2018",
month = jan,
doi = "10.1111/pcmr.12620",
language = "English",
volume = "31",
pages = "51--63",
journal = "Pigment Cell and Melanoma Research",
issn = "1755-1471",
publisher = "Wiley-Blackwell",
number = "1",
}