title: Epigenetic reprogramming of melanoma cells by vitamin C treatment.
abstract: BACKGROUND
  The loss of 5-hydroxymethylcytosine (5hmC) has been identified as a novel epigenetic hallmark for melanoma. One of the known mechanisms underlying the loss of 5hmC is the decrease in expression of ten-eleven translocation family dioxygenase (TET) genes, which encode enzymes that catalyze the generation of 5hmC. Overexpressing TET2 was shown to partially reestablish a normal 5hmC profile in melanoma and decrease invasiveness in rodents. However, the feasibility to overexpress TETs in patients remains unclear. We and others have recently demonstrated that TETs require vitamin C as a cofactor to generate 5hmC. This finding prompted us to test whether vitamin C, as an alternative to overexpressing TETs, could rebuild 5hmC content in melanoma.
  
  
  RESULTS
  Consistent with previous reports, we found that the expression of TETs was decreased in various melanoma cell lines. In contrast, the expressions of sodium-dependent vitamin C transporters (SVCTs) were down-regulated in cell lines derived from melanoma metastases. Treatment of vitamin C at the physiological level (0.1 mM) promoted the content of 5hmC in melanoma cell lines derived from different stages toward the level of healthy melanocytes, which was comparable to the effect of overexpressing TET2. Vitamin C treatment decreased the malignancy of metastatic A2058 cells by inhibiting migration and anchorage-independent growth, while not exerting any effect on the rate of proliferation. Further, vitamin C treatment caused alterations in genome-wide transcriptions shown by RNA-seq, predominantly in ArhGAP30 and genes involved in extracellular matrix remodeling, which could underlie the decreased malignant phenotypes.
  
  
  CONCLUSIONS
  Our data support the idea that vitamin C treatment increases 5hmC content in melanoma cells, while causing a decrease in tumor-cell invasiveness and clonogenic growth in soft agar. Thus, vitamin C could be a potential epigenetic treatment for melanoma.
authors.affiliation: John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Gustafson
authors.affiliation: Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA ; Department of Molecular Biology Laboratory, Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, 200233 China.
authors.forename: Cuixia
authors.initials: C
authors.lastname: Yang
authors.affiliation: John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Dickson
authors.affiliation: Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Shao
authors.affiliation: John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Van Booven
authors.affiliation: Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136 USA ; Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: J William
authors.initials: JW
authors.lastname: Harbour
authors.affiliation: Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA ; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Liu
authors.affiliation: John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136 USA ; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136 USA ; Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136 USA.
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Wang
keywords: 5-hydroxymethycytosine; Epigenetic reprogramming; Melanoma; RNA-seq; Vitamin C