MX 2 is a novel regulator of cell cycle in melanoma cells

MX2 protein is a dynamin‐like GTPase2 that has recently been identified as an interferon‐induced restriction factor of HIV‐1 and other primate lentiviruses. A single nucleotide polymorphism (SNP), rs45430, in an intron of the MX2 gene, was previously reported as a novel melanoma susceptibility locus in genome‐wide association studies. Functionally, however, it is still unclear whether and how MX2 contributes to melanoma susceptibility and tumorigenesis. Here, we show that MX2 is differentially expressed in melanoma tumors and cell lines, with most metastatic cell lines showing lower MX2 expression than primary melanoma cell lines and melanocytes. Furthermore, high expression of MX2 RNA in primary melanoma tumors is associated with better patient survival. Overexpression of MX2 reduces in vivo proliferation partially through inhibition of AKT activation, suggesting that it can act as a tumor suppressor in melanoma. However, we have also identified a subset of melanoma cell lines with high endogenous MX2 expression where downregulation of MX2 leads to reduced proliferation. In these cells, MX2 downregulation interfered with DNA replication and cell cycle processes. Collectively, our data for the first time show that MX2 is functionally involved in the regulation of melanoma proliferation but that its function is context‐dependent

HFE genotype modifies the influence of heme iron intake on iron status

Background: Public health policy to prevent iron deficiency through food fortification or other measures may be disadvantageous to people with hereditary hemochromatosis. Methods: From a cohort of U.K. women, 2531 women were typed for C282Y and H63D mutations in the hemochromatosis gene. These women completed food frequency questionnaires and provided blood for iron status. Results: C282Y homozygotes (n = 31) had serum ferritin concentrations 2.4 times higher (95% confidence interval = 1.9–3.1) than wild types (n = 1774), but heterozygotes (n = 726) were not different from wild types. H63D genotype had no effect on its own. The effect of heme iron intake (from meat, fish, and poultry) was 2.0 times greater (1.2–3.2) on C282Y homozygotes than other groups. Nonheme iron had little effect. Conclusions: There may be scope for dietary intervention in women homozygous for the C282Y mutation. C282Y heterozygotes and H63D homozygotes and heterozygotes have similar serum ferritin concentrations to wild type and need not reduce their meat intake other than as part of a normal healthy diet

Genetic and Environmental Determinants of Immune Response to Cutaneous Melanoma

The immune response to melanoma improves the survival in untreated patients and predicts the response to immune checkpoint blockade. Here, we report genetic and environmental predictors of the immune response in a large primary cutaneous melanoma cohort. Bioinformatic analysis of 703 tumor transcriptomes was used to infer immune cell infiltration and to categorize tumors into immune subgroups, which were then investigated for association with biological pathways, clinicopathologic factors, and copy number alterations. Three subgroups, with “low”, “intermediate”, and “high” immune signals, were identified in primary tumors and replicated in metastatic tumors. Genes in the low subgroup were enriched for cell-cycle and metabolic pathways, whereas genes in the high subgroup were enriched for IFN and NF-κB signaling. We identified high MYC expression partially driven by amplification, HLA-B downregulation, and deletion of IFNγ and NF-κB pathway genes as the regulators of immune suppression. Furthermore, we showed that cigarette smoking, a globally detrimental environmental factor, modulates immunity, reducing the survival primarily in patients with a strong immune response. Together, these analyses identify a set of factors that can be easily assessed that may serve as predictors of response to immunotherapy in patients with melanoma. Significance: These findings identify novel genetic and environmental modulators of the immune response against primary cutaneous melanoma and predict their impact on patient survival

Role of the EGF +61A>G polymorphism in melanoma pathogenesis: an experience on a large series of Italian cases and controls

<p>Abstract</p> <p>Background</p> <p>A single nucleotide polymorphism (61A>G) in the epidermal growth factor (<it>EGF</it>) gene has been implicated in both melanoma pathogenesis and increased melanoma risk. To further evaluate this association, we conducted a case-control study in a clinic-based Italian population.</p> <p>Methods</p> <p>Individuals with less than 10 (N = 127) or more than 100 (N = 128) benign nevi, and patients with cutaneous melanoma (N = 418) were investigated for the <it>EGF </it>+61A>G polymorphism, using an automated sequencing approach.</p> <p>Results</p> <p>Overall, no difference in <it>EGF </it>genotype frequencies was observed among subjects with different number of nevi as well as when non-melanoma healthy controls were compared with the melanoma patients. However, a heterogeneous distribution of the frequencies of the G/G genotype was detected among cases and controls originating from North Italy (21.1 and 18.3%, respectively) vs. those from South Italy (12.6 and 17.1%, respectively).</p> <p>Conclusion</p> <p>Our findings further suggest that <it>EGF </it>+61A>G polymorphism may have a limited impact on predisposition and/or pathogenesis of melanoma and its prevalence may vary in different populations.</p

Vitamin D receptor polymorphisms in patients with cutaneous melanoma

The vitamin D receptor (VDR) gene has been associated with cancer risk, but only a few polymorphisms have been studied in relation to melanoma risk and the results have been inconsistent. We examined 38 VDR gene single nucleotide polymorphisms (SNPs) in a large international multicenter population‐based case‐control study of melanoma. Buccal DNAs were obtained from 1,207 people with incident multiple primary melanoma and 2,469 with incident single primary melanoma. SNPs with known or suspected impact on VDR activity, haplotype tagging SNPs with ≥10% minor allele frequency in Caucasians, and SNPs reported as significant in other association studies were examined. Logistic regression was used to calculate the relative risks conferred by the individual SNP. Eight of 38 SNPs in the promoter, coding, and 3′ gene regions were individually significantly associated with multiple primary melanoma after adjusting for covariates. The estimated increase in risk for individuals who were homozygous for the minor allele ranged from 25 to 33% for six polymorphisms: rs10875712 (odds ratios [OR] 1.28; 95% confidence interval (CI), 1.01–1.62), rs4760674 (OR 1.33; 95% CI, 1.06–1.67), rs7139166 (OR 1.26; 95%CI, 1.02–1.56), rs4516035 (OR 1.25; 95%CI, 1.01–1.55), rs11168287 (OR 1.27; 95%CI, 1.03–1.57) and rs1544410 (OR 1.30; 95%CI, 1.04–1.63); for two polymorphisms, homozygous carriers had a decreased risk: rs7305032 (OR 0.81; 95%CI 0.65–1.02) and rs7965281 (OR, 0.78; 95%CI, 0.62–0.99). We recognize the potential false positive findings because of multiple comparisons; however, the eight significant SNPs in our study outnumbered the two significant tests expected to occur by chance. The VDR may play a role in melanomagenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88076/1/26023_ftp.pd

Vitamin D-VDR signaling inhibits Wnt/beta-catenin-mediated melanoma progression and promotes anti-tumor immunity

1α,25-dihydroxyvitamin D3 signals via the Vitamin D Receptor (VDR). Higher serum vitamin D is associated with thinner primary melanoma and better outcome, although a causal mechanism has not been established. As melanoma patients commonly avoid sun exposure, and consequent vitamin D deficiency might worsen outcomes, we interrogated 703 primary melanoma transcriptomes to understand the role of vitamin D-VDR signalling and replicated the findings in TCGA metastases. VDR expression was independently protective for melanoma death in both primary and metastatic disease. High tumor VDR expression was associated with upregulation of pathways mediating anti-tumor immunity and correspondingly with higher imputed immune cell scores and histologically detected tumor infiltrating lymphocytes (TILs). High VDR expressing tumors had downregulation of proliferative pathways, notably Wnt/beta-catenin signaling. Deleterious low VDR levels resulted from promoter methylation and gene deletion in metastases. Vitamin D deficiency (< 25 nmol/l ~ 10 ng/ml) shortened survival in primary melanoma in a VDR-dependent manner. In vitro functional validation studies showed that elevated vitamin D-VDR signaling inhibited Wnt/beta-catenin signaling genes. Murine melanoma cells overexpressing VDR produced fewer pulmonary metastases than controls in tail vein metastasis assays. In summary, vitamin D-VDR signaling contributes to controlling pro-proliferative/immunosuppresive Wnt/beta-catenin signaling in melanoma and this is associated with less metastatic disease and stronger host immune responses. This is evidence of the causal relationship between vitamin D-VDR signaling and melanoma survival which should be explored as a therapeutic target in primary resistance to checkpoint blockade

Association of MC1R Variants and host phenotypes with melanoma risk in CDKN2A mutation carriers: a GenoMEL study

&lt;p&gt;&lt;b&gt;Background&lt;/b&gt; Carrying the cyclin-dependent kinase inhibitor 2A (CDKN2A) germline mutations is associated with a high risk for melanoma. Penetrance of CDKN2A mutations is modified by pigmentation characteristics, nevus phenotypes, and some variants of the melanocortin-1 receptor gene (MC1R), which is known to have a role in the pigmentation process. However, investigation of the associations of both MC1R variants and host phenotypes with melanoma risk has been limited.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods&lt;/b&gt; We included 815 CDKN2A mutation carriers (473 affected, and 342 unaffected, with melanoma) from 186 families from 15 centers in Europe, North America, and Australia who participated in the Melanoma Genetics Consortium. In this family-based study, we assessed the associations of the four most frequent MC1R variants (V60L, V92M, R151C, and R160W) and the number of variants (1, &#8805;2 variants), alone or jointly with the host phenotypes (hair color, propensity to sunburn, and number of nevi), with melanoma risk in CDKN2A mutation carriers. These associations were estimated and tested using generalized estimating equations. All statistical tests were two-sided.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results&lt;/b&gt; Carrying any one of the four most frequent MC1R variants (V60L, V92M, R151C, R160W) in CDKN2A mutation carriers was associated with a statistically significantly increased risk for melanoma across all continents (1.24 × 10−6 &#8804; P &#8804; .0007). A consistent pattern of increase in melanoma risk was also associated with increase in number of MC1R variants. The risk of melanoma associated with at least two MC1R variants was 2.6-fold higher than the risk associated with only one variant (odds ratio = 5.83 [95% confidence interval = 3.60 to 9.46] vs 2.25 [95% confidence interval = 1.44 to 3.52]; Ptrend = 1.86 × 10−8). The joint analysis of MC1R variants and host phenotypes showed statistically significant associations of melanoma risk, together with MC1R variants (.0001 &#8804; P &#8804; .04), hair color (.006 &#8804; P &#8804; .06), and number of nevi (6.9 × 10−6 &#8804; P &#8804; .02).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusion&lt;/b&gt; Results show that MC1R variants, hair color, and number of nevi were jointly associated with melanoma risk in CDKN2A mutation carriers. This joint association may have important consequences for risk assessments in familial settings.&lt;/p&gt

Transcriptomic Analysis Reveals Prognostic Molecular Signatures of Stage I Melanoma

Purpose: Previously identified transcriptomic signatures have been based on primary and metastatic melanomas with relatively few American Joint Committee on Cancer (AJCC) stage I tumors, given difficulties in sampling small tumors. The advent of adjuvant therapies has highlighted the need for better prognostic and predictive biomarkers, especially for AJCC stage I and stage II disease. Experimental Design: A total of 687 primary melanoma transcriptomes were generated from the Leeds Melanoma Cohort (LMC). The prognostic value of existing signatures across all the AJCC stages was tested. Unsupervised clustering was performed, and the prognostic value of the resultant signature was compared with that of sentinel node biopsy (SNB) and tested as a biomarker in three published immunotherapy datasets. Results: Previous Lund and The Cancer Genome Atlas signatures predicted outcome in the LMC dataset (P = 10−8 to 10−4) but showed a significant interaction with AJCC stage (P = 0.04) and did not predict outcome in stage I tumors (P = 0.3–0.7). Consensus-based classification of the LMC dataset identified six classes that predicted outcome, notably in stage I disease. LMC class was a similar indicator of prognosis when compared with SNB, and it added prognostic value to the genes reported by Gerami and colleagues. One particular LMC class consistently predicted poor outcome in patients receiving immunotherapy in two of three tested datasets. Biological characterization of this class revealed high JUN and AXL expression and evidence of epithelial-to-mesenchymal transition. Conclusions: A transcriptomic signature of primary melanoma was identified with prognostic value, including in stage I melanoma and in patients undergoing immunotherapy