Document Type

Dissertation - Open Access

Award Date

2019

Degree Name

Doctor of Philosophy (PhD)

Department / School

Chemistry and Biochemistry

First Advisor

Fathi Halaweish

Keywords

in-silico, ORM-Br, Ormeloxifene, trifluoromethylated

Abstract

The established records of the safety of Ormeloxifene along with its favorable bioavailability and ability to inhibit rapid cell proliferation in the endometrium during embryonic implantation has made it one of the best drug candidates for controlling undesirable rapid cell growth such as endometriosis and cancerous tumor conditions. Recent studies have confirmed the effectiveness of Ormeloxifene to suppress and inhibit epithelial-mesenchymal transition process as evidenced by repression of N-cadherin, slug, snail, vimentin, MMPs, β-catenin/TCF-4 transcriptional activity and induce the expression of pGSK3b. Recently conducted studies have revealed the dynamic binding of ormeloxifene with β-catenin, GSK3b, CDK4, and other downstream EGFR. In this communication, a novel Ormeloxifene analogs with inhibitory activities towards epidermal growth factor receptor (EGFR) is used to develop a potential drug candidate for the treatment of ovarian cancer. Molecular modeling results revealed that the introduction of electron withdrawing group at the para position of aromatic at C-3 such as JA-16 increased binding affinity in GSK3B binding pocket relative to Ormeloxifene. Substitution of trifluoromethylated moiety on the phenoxy position and incorporation of pyrrolidine side chains at C-7 of the benzopyran framework such as JA-15, JA-16, JA-17, and JA-18 improved the inhibitory activity of the compound in the crystal structure of CDK2 as compared to Ormeloxifene. A total of 25 analogs have been synthesized and biologically evaluated. Cell proliferation inhibitory assay revealed the ability of JA-15, ORM-Br, and JA-28 to inhibit ovarian cancer cell line (A2780) with IC50 of 9μM, 11.2μM, and 17.6μM respectively. Cell cycle analysis performed by flow cytometry revealed that JA-15 arrest A2780 cells in the G0 – G1 phase. JA-15 showed an increase in the fraction of cells in the G0-G1 phase with 61.98% compared to the control with 53.42%. However, JA-28 exhibited an increase in the fractions of cells in the G2-M phase with 8.74% relative to 3.52% for control. This result indicates that JA-15 has the potential to chemotherapeutic effects because it arrests (A2780) ovarian cell cycle in G0-G1 phase. To explore the impact of ORM analogs on other cancer cell lines, ORM-Br was tested on cervical cancer cell lines (CaSki and SiHa). Western blot analysis conducted to establish the effect of ORM-Br on β-catenin degradation after using translational inhibitor (cycloheximide) showed a significant decrease in protein levels of β-catenin in CaSki and SiHa cells relative to cycloheximide treatment. The clonogenic assay revealed that ORM-Br suppresses the clonogenic potential of CaSki and SiHa cell lines. On the other hand, ORM-Br inhibits the migration of cervical cancer cells as predicted by agarose bead assay. Boyden chamber and xCELLigence assay revealed that Br-ORM inhibits the invasion of cervical cancer (CaSki and SiHa) cells. There was a decrease in the expression of nuclear β-catenin in the cytoplasm of cervical cancer cell lines when subjected to western blot analysis to detect the protein levels of β-catenin. Cell lysates and western blot analysis conducted for EMT markers and MMPs analysis showed the ability of ORM-Br to inhibit the EMT associated markers in both CaSki and SiHa cell lines. The knowledge of varying inhibitory activity of JA-15, JA-28, and ORM-Br on multiple pathways is a possible lead towards the discovery of potential anticancer agent; we propose that ormeloxifene framework can be altered to generate possible drug candidates, which can affect multiple targets following multi-faceted drug strategies to combat ovarian cancer.

Library of Congress Subject Headings

Ovaries -- Cancer -- Treatment.
Selective estrogen receptor modulators.
Drug targeting.

Format

application/pdf

Number of Pages

335

Publisher

South Dakota State University

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Chemistry Commons

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Rights Statement

In Copyright