Defense Date


Document Type


Degree Name

Master of Science


Human Genetics

First Advisor

Paul B. Fisher

Second Advisor

Joyce Lloyd

Third Advisor

Steven Grant


Melanoma differentiation associated gene 7/Interleukin-24 (MDA-7/IL-24) is a secreted cytokine which acts as a tumor suppressor. It is capable of selectively killing cancer cells, regardless of anatomic origin, while sparing normal cells. miRNAs are master regulators of gene expression that can play two roles in cancer: tumor-suppression and oncogenesis. We identified a number of miRNAs that are regulated by MDA-7/IL-24 using a PCR plate array containing probes for miRNAs known to play a role in prostate cancer. We independently validated the array with qRT-PCR to identify three miRNAs which are downregulated by MDA-7/IL-24 treatment in DU145, PC3, and PC3ML prostate cancer lines. These miRNAs were miR-125a, miR-145, and miR-23b. Their gene targets were identified using TargetScan and confirmed to be regulated in our prostate cancer model. NLRC5, KLF4, and KLF15, respectively, were upregulated after treatment with MDA-7/IL-24. We focused on NLRC5 as a novel target of MDA-7/IL-24, which plays a role in immune evasion by cancer cells. NLRC5 is upregulated following inhibition of miR-125a. It is not downregulated by overexpression of miR-125a which suggests that more than one miRNA may be acting to regulate its expression. Finally, we determined that miR-125a is downregulated by MDA-7 through DICER, an important processing enzyme for miRNA biogenesis.


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