| 1. |
- Artomov, Mykyta, et al.
(författare)
-
Rare variant, gene-based association study of hereditary melanoma using whole-exome sequencing
- 2017
-
Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 109:12
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Extraordinary progress has been made in our understanding of common variants in many diseases, including melanoma. Because the contribution of rare coding variants is not as well characterized, we performed an exome-wide, gene-based association study of familial cutaneous melanoma (CM) and ocular melanoma (OM). Methods: Using 11 990 jointly processed individual DNA samples, whole-exome sequencing was performed, followed by largescale joint variant calling using GATK (Genome Analysis ToolKit). PLINK/SEQ was used for statistical analysis of genetic variation. Fourmodels were used to estimate the association among different types of variants. In vitro functional validation was performed using three humanmelanoma cell lines in 2D and 3D proliferation assays. In vivo tumor growth was assessed using xenografts of humanmelanoma A375melanoma cells in nudemice (eightmice per group). All statistical tests were two-sided. Results: Strong signals were detected for CDKN2A (Pmin = 6.16×10-8) in the CM cohort (n=273) and BAP1 (Pmin = 3.83×10-6) in the OM (n=99) cohort. Eleven genes that exhibited borderline association (P < 10-4) were independently validated using The Cancer Genome Atlas melanoma cohort (379 CM, 47 OM) and a matched set of 3563 European controls with CDKN2A (P = .009), BAP1 (P = .03), and EBF3 (P = 4.75×10-4), a candidate risk locus, all showing evidence of replication. EBF3 was then evaluated using germline data from a set of 132 familial melanoma cases and 4769 controls of UK origin (joint P = 1.37×10-5). Somatically, loss of EBF3 expression correlated with progression, poorer outcome, and high MITF tumors. Functionally, induction of EBF3 in melanoma cells reduced cell growth in vitro, retarded tumor formation in vivo, and reduced MITF levels. Conclusions: The results of this large rare variant germline association study further define the mutational landscape of hereditary melanoma and implicate EBF3 as a possible CM predisposition gene.
|
|
| 2. |
- Ji, Zhenyu, et al.
(författare)
-
MITF Modulates Therapeutic Resistance through EGFR Signaling.
- 2015
-
Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 135:7, s. 1863-1872
-
Tidskriftsartikel (refereegranskat)abstract
- Response to targeted therapies varies significantly despite shared oncogenic mutations. Nowhere is this more apparent than in BRAF(V600E)-mutated melanomas where initial drug response can be striking and yet relapse is commonplace. Resistance to BRAF inhibitors have been attributed to the activation of various receptor tyrosine kinases (RTKs) though the underlying mechanisms have been largely uncharacterized. Here, we found that EGFR induced vemurafenib resistance is ligand dependent. We then employed whole-genome expression analysis and discovererd that vemurafenib resistance correlated with the loss of MITF, along with its melanocyte lineage program, and with the activation of EGFR signaling. An inverse relationship between MITF, vemurafenib resistance and EGFR was then observed in patient samples of recurrent melanoma and was conserved across melanoma cell lines and patients' tumor specimens. Functional studies revealed that MITF depletion activated EGFR signaling and consequently recapitulated the resistance phenotype. In contrast, forced expression of MITF in melanoma and colon cancer cells inhibited EGFR and conferred sensitivity to BRAF/MEK inhibitors. These findings indicate that an "autocrine drug resistance loop" is suppressed by melanocyte lineage signal(s), such as MITF. This resistance loop modulates drug response and could explain the unique sensitivity of melanomas to BRAF inhibition.Journal of Investigative Dermatology accepted article preview online, 19 March 2015. doi:10.1038/jid.2015.105.
|
|
| 3. |
- Kumar, Raj, et al.
(författare)
-
BAP1 Plays a Survival Role in Cutaneous Melanoma.
- 2015
-
Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 135:4, s. 1089-1097
-
Tidskriftsartikel (refereegranskat)abstract
- Although the pattern of BAP1 inactivation in ocular melanoma specimens and in the BAP1 cutaneous/ocular melanoma (CM/OM) predisposition syndrome suggests a tumor suppressor function, the specific role of this gene in the pathogenesis of cutaneous melanoma is not fully understood. We thus set out to characterize BAP1 in cutaneous melanoma and discovered an unexpected pro-survival effect of this protein. Tissue and cell lines analysis showed that BAP1 expression was maintained, rather than lost, in primary melanomas compared to nevi and normal skin. Genetic depletion of BAP1 in melanoma cells reduced proliferation and colony forming capability, induced apoptosis and inhibited melanoma tumor growth in vivo. On the molecular level, suppression of BAP1 led to a concomitant drop in the protein levels of survivin a member of anti-apoptotic proteins and a known mediator of melanoma survival. Restoration of survivin in melanoma cells partially rescued the growth-retarding effects of BAP1 loss. In contrast to melanoma cells, stable overexpression of BAP1 into immortalized but non-transformed melanocytes did suppress proliferation and reduce survivin. Taken together, these studies demonstrate that BAP1 may play a growth-sustaining role in melanoma cells, but that its impact on ubiquitination underpins a complex physiology which is context and cell dependent.Journal of Investigative Dermatology accepted article preview online, 18 December 2014. doi:10.1038/jid.2014.528.
|
|
