Epigenetic inactivation of microRNA in male germ cell cancer Personnel: Lee, Cheung, Chan, Rennert MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been shown to be deregulated in many diseases including cancer. An intertwined connection between epigenetics and miRNAs has been supported by the recent identification of a specific subgroup of miRNAs called """"""""epi-miRNAs"""""""" that can directly and indirectly modulate the activity of the epigenetic machinery. Using a genome-wide approach for studying differential methylation in testicular germ cell tumor cell line, we previously identified a novel hypermethylated locus on chromosome 1. Genomic mapping revealed that the hypermethylated region overlapped with a mircroRNA candidate, miR-199a and its upstream promoter region. Bisulfite sequencing and treatment with DNA methyltransferase inhibitor 5-aza in the Ntera-2 testis cancer cells confirmed the same observation in the tiling microarray data. Changes in DNA methylation are a hallmark of cancer, and are frequently associated with cancer progression. Epigenomic profiling revealed a conserved region in intron-14 of dynamin 3, located at 1q24.3;its hypermethylation correlated with testicular cancer progression, and silencing of miR-199a. Re-expression of miR-199a in testicular cancer cells suppressed cell growth, cancer migration, invasion, and metastasis. miR-199a-5p, one of two mature miRNA species derived from miR-199a, is associated with cancer progression. We identified an embryonal carcinoma antigen, podocalyxin-like protein 1 (PODXL), as a target of miR-199a-5p. PODXL is an anti-adhesive protein overexpressed in aggressive testicular cancer. Knockdown of PODXL suppressed cancer invasion. The inverse relationship between PODXL and miR-199a-5p expression suggests that PODXL is one of the downstream effectors mediating cancer invasion and metastasis. This report links DNA methylation, miR-199a dysregulation, and PODXL expression as a mechanism to explain testicular cancer progression.

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Cheung, H-H; Davis, A J; Lee, T-L et al. (2011) Methylation of an intronic region regulates miR-199a in testicular tumor malignancy. Oncogene 30:3404-15
Lee, Tin-Lap; Li, Yunmin; Cheung, Hoi-Hung et al. (2010) GonadSAGE: a comprehensive SAGE database for transcript discovery on male embryonic gonad development. Bioinformatics 26:585-6
Nagrani, Sohan R; Levens, Eric D; Baxendale, Vanessa et al. (2010) Methylation patterns of Brahma during spermatogenesis and oogenesis: potential implications. Fertil Steril :
Cheung, H H; Lee, T L; Davis, A J et al. (2010) Genome-wide DNA methylation profiling reveals novel epigenetically regulated genes and non-coding RNAs in human testicular cancer. Br J Cancer 102:419-27
Raygada, Margarita; Arthur, Diane C; Wayne, Alan S et al. (2010) Juvenile xanthogranuloma in a child with previously unsuspected neurofibromatosis type 1 and juvenile myelomonocytic leukemia. Pediatr Blood Cancer 54:173-5
Lee, Tin-Lap; Cheung, Hoi-Hung; Claus, Janek et al. (2009) GermSAGE: a comprehensive SAGE database for transcript discovery on male germ cell development. Nucleic Acids Res 37:D891-7
Cheung, Hoi-Hung; Lee, Tin-Lap; Rennert, Owen M et al. (2009) DNA methylation of cancer genome. Birth Defects Res C Embryo Today 87:335-50
Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M et al. (2009) Genomic landscape of developing male germ cells. Birth Defects Res C Embryo Today 87:43-63