Martin Tenniswood

  • Martin Tenniswood


    Dr. Tenniswood’s laboratory is interested in characterizing the mechanisms that regulate specific miRNA levels in prostate cancer cells. The demonstration that 1,25(OH)2D3 and T modulate the steady state level of numerous mRNA transcripts through modulation of stability raises the question as to how 1,25(OH)2D3 and T synergistically modulate miRNA transcription and processing. To examine this question we will initially focus on the transcriptional regulation of the miR-17/92 cluster. Based on our array data and qPCR analysis, miR-17 and 20a are repressed synergistically by 1,25(OH)2D3 and T. The miR-17/92 cluster is located in intron 3 of C13orf25. c-MYC, E2F1 and CCND1 have been shown to bind to the promoter region of C13orf25 to modulate cell cycle progression and tumor angiogenesis. The expression of all four exons of C13orf25 demonstrates a positive correlation to miR-17/92 with the highest correlation between miR-17 and Exon 3 of C13orf25. The concordance between the two transcripts suggests that the synergy between 1,25(OH)2D3 and T is affecting the transcription of C13orf25 rather than processing of the miRNA. However, in silico analysis of the 10 kb region upstream of the miR-17/92 cluster using the BlastN search engine has not identified any potential VDRE or ARE consensus sites. This suggests that suppression of C13orf25 maybe indirect, possibly through 1,25(OH)2D3 and T mediated repression of c-Myc, E2Fs and miR-22 and 29ab. To decipher the transcriptional regulation of C13orf25, the steady state level of C13orf25 in prostate cancer cell lines after treatment of 1,25(OH)2D3 in the absence and presence of T will be assessed by qPCR. Transcription rate measurements and chromatin immunoprecipitation assays will be used to evaluate promoter occupancy, focusing on the binding of cell cycle regulators and basal transcription factors, as well as VDR and AR to the promoter in response to T and 1,25(OH)2D3.