Document Type

Dissertation

Date of Award

5-2024

School/College

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 Jr.

Committee Member 3

Ayodotun Sodipe

Committee Member 4

Bobby Wilson

Keywords

Cell cycle progression, Haloperidol, miRNA-hsa-Let-7c, Paradoxical behavior, PKB/AKT Pathway, Proliferation

Abstract

Haloperidol is a typical antipsychotic drug; it is widely used for people with various psychiatric conditions such as schizophrenia, bipolar disorder, major depressive disorder, and dementia. Despite its effectiveness in controlling delusions, hallucinations, agitation, and other disruptive behavioral symptoms in these psychiatric conditions, it has adverse side effects such as extrapyramidal manifestation and endocrinologic and metabolic changes. Initial evidence shows that haloperidol has antitumor properties in several cancer types by inhibiting cell proliferation and inducing apoptosis. However, other reports indicate that haloperidol promotes cell proliferation in other cells, raising concerns about its association with an increased risk of cancer which suggests haloperidol has a paradoxical behavior in different cell types. Most haloperidol studies focused on cancer cells, not normal cells. However, a study showed that haloperidol protects lung endothelial cells from injury and another study proved that haloperidol stimulated the cellular transformation of human endometrial epithelial cells (HECCs) into human endometrial carcinoma cells (HECCs). Nevertheless, the role of haloperidol on the immortalized non-tumorigenic epithelial cell line, human bronchial epithelium BEAS-2B, remains unknown. Also, the paradoxical effect of haloperidol in cancer and non-cancer cells and on Protein Kinase B protein kinase B (PKB/AKT) and its downstream regulatory proteins is puzzling. PKB/AKT promotes cell proliferation, survival, and metabolism, including tumorigenesis, by phosphorylating its downstream target proteins. Additionally, studies have proven that Several miRNAs were observed to be differentially expressed by antipsychotic drug treatment. However, limited studies directly investigate microRNAs' role in the haloperidol paradoxical effect. Therefore, it is essential to study the effects of haloperidol on PKB/AKT and its downstream regulatory proteins and explore the role of microRNAs targeting PKB/Akt messenger ribonucleic acid (mRNA) in regulating haloperidol's paradoxical behavior, focusing on miRNA, hsa-Let-7c, known for its roles as a cycle regulator, tumor suppressor, as well as its involvement in regulating neuronal differentiation, neural subtype specification, and synapse formation in humans. This research proposes two aims to address these complexities. Aim 1: this study focuses on understanding haloperidol’s paradoxical (i.e., contradictory) behavior relative to cell proliferation in non-cancerous cellular environments. The hypothesis is that haloperidol promotes cell proliferation and survival, increasing cell cycle progression gene expression in BEAS-2B cells. Aim 2: this study deciphers whether microRNAs (miRNAs) prevent haloperidol’s paradoxical behavior that induces cell proliferation through the PKB/AKT signaling pathway in BEAS-2B cells since the miRNAs are suitable biomarkers and can be utilized for determining the paradoxical behavior of PBK/AKT in different cellular environments. The hypothesis is that overexpression of miRNA (i.e., hsa-let-7c DNA construct, which targets PKB/AKT mRNA) would reduce PKB/AKT-induced expression by haloperidol in BEAS-2B cells, reducing cell proliferation and promoting apoptosis. To achieve the study aims and fulfill the study hypotheses, BEAS-2B cells were treated with 3.5 µM of haloperidol for 24 and 48 hours, and they were treated with 3.5 µM of haloperidol and transfected with hsa-let-7c- GFP-DNA construct for 24 and 48 hours. Also, untreated control experiments were included. After each interval, the cells were examined under an inverted microscope; protein and RNA were isolated; cDNA was synthesized; semi-qPCR and Western blot were performed. Li-COR Odyssey® Fc imager (LI-COR Biosciences, Lincoln, NE) using Image Studio Lite Version 5.2 (LI-COR Biosciences, Lincoln, NE) was used for visualization and quantification. Haloperidol increases BEAS-2B cell proliferation without hsa-let-7c expression, suggesting it promotes cell cycle progression. Conversely, overexpression of miRNA, hsa-let-7c, inhibits haloperidol-induced cell proliferation and PBK/AKT, including the downstream genes regulated by PBK/AKT. Conclusion: haloperidol-induced PBK/AKT expression to promote BEAS-2B cell proliferation and survival. However, overexpression of hsa-let-7c inhibits haloperidol-induced PBK/AKT and its downstream target genes. This study validates the proliferating paradoxical effect of haloperidol. It demonstrates that miRNA, hsa-let-7c, regulates PBK/AKT mRNA, reducing its protein expression in BEAS-2B cells and suggesting hsa-let-7c is a suitable biomarker for solving haloperidol paradoxical behaviors involving cell proliferation, survival, and apoptosis.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.