Document Type


Date of Award



College of Science, Engineering, and Technology (COSET)

Degree Name

Ph.D. in Environmental Toxicology

Committee Chairperson

Shodimu-Emmanuel Olufemi

Committee Member 1

Desiree Jackson

Committee Member 2

Hector Miranda

Committee Member 3

Bobby Wilson

Committee Member 4

Ayodotun Sodipe


Abemaciclib, cell cycle, microRNAs, Palbociclib, PC-3, Ribociclib


MicroRNA was first discovered in C. elegans as small temporal RNA (stRNA) that does not code for protein. Since being discovered they have played a significant role in regulating gene expression at the post-transcriptional level. miRNAs are found in various organisms, and they bind to the 3' untranslated regions to inhibit translation and cause mRNA degradation. Some drugs are involved in cell cycle regulation such as Palbociclib, Ribociclib (LEE011), and Abemaciclib (LY2835219), that causes G1 arrest impeding cell proliferation. Cyclin D1 (CCND1) is supported by the cell cycle making it into a functional product. When undergoing a chemical reaction, the composition of both the cyclins and the cyclin-dependent kinase (CDK), such as CDK4 arrange to replicate the DNA and promote cell division. These drugs could in some cases be involved in regulating the apoptotic pathway since some genes in that pathway are known to influence cell division. Protein Kinase B (AKT) has been known to promote proliferation as well as apoptosis. AKT is key in regulating genes such as B-cell lymphoma-extra large (Bcl-xL), a transmembrane molecule that prevents the initiation of apoptosis, Caspase-9 (CASP9), that acts as an initiator to cleave other caspases to cause apoptosis to occur. Currently, drugs and microRNAs are used to treat several human diseases. The efficiency between microRNAs and xenobiotic drugs is still in the developing stages and looking at key regulators in both the cell cycle and apoptotic pathway can help draw comparisons between the two in how potent they are. There are two aims for this study. Aim 1: To demonstrate that the overexpression of miRNA (i.e., hsa-miR-3202 and hsa-miR-7152) and xenobiotic drugs (i.e., Abemaciclib ((LY2835219), Ribociclib (LEE011), and Palbociclib) have a similar effect on the cell cycle regulatory gene in PC-3 cells. Aim 2: To demonstrate in PC-3 cells that the overexpression of miRNA (i.e., hsa-miR-3202 and hsa-miR-7152) and xenobiotic drugs (i.e., Abemaciclib ((LY2835219), Ribociclib (LEE011), and Palbociclib) are not similar on the genes in the AKT pathways since the xenobiotic drugs have a direct interaction blockage and the miRNAs affect mRNA translation; even though the miRNAs are not predicted to target the mRNA AKT pathway. We hypothesize that overexpression of the miRNAs or the xenobiotic drugs in PC-3 cells will similarly reduce the protein expression of CDK4, CDK6, and cyclin D1 since the miRNAs have a higher target predicted score at the miRDB (miR DataBase). As well as overexpression of miRNAs (i.e., hsa-miR-3202 and hsa-miR-7152) will reduce protein expression of genes in the AKT pathways but the xenobiotic drugs (i.e., Abemaciclib ((LY2835219), Ribociclib (LEE011), and Palbociclib) will not. The results suggested that the xenobiotic drugs ultimately inhibit the protein expression of the cell cycle and apoptotic regulators in PC-3 cells as compared to the overexpressed microRNAs. This is the first report that compared and showed that overexpressed miRs are less potent than xenobiotic drugs that directly interact with their target proteins. The result suggests that miRNA tested in the study as compared to the drugs may be less harmful or toxic to cells. Yet other miRNAs may be more potent, especially those miRNAs that function as tumor suppressors or oncogenes. The results also show that genes in the AKT pathway, which is upstream of our target genes, are also affected by the miRNA and the xenobiotic drugs to a certain extent in PC-3 cells.



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