Date of Award

2022-04-01

Degree Name

Doctor of Philosophy

Department

Environmental Science and Engineering

Advisor(s)

Md M. Nurunnabi

Abstract

Apoptosis is a naturally occurring cell death mechanism to remove the selective cell population. B-cell leukemia/lymphoma-2 (BCL-2) family protein plays a critical role in activating the upstream apoptosis signaling pathway, primarily the intrinsic apoptosis pathway. The BCL-2 family consists of both pro-and anti-apoptotic proteins, which are structurally and functionally similar, containing up to four BCL-2 homologies (BH) motifs (BH1-4). Defecting apoptosis along this signaling pathway can lead to various events, including malignant cell transformation, tumor metastasis, tissue fibrosis, and drug resistance. In fibrosis, the aberrant apoptosis signaling also activates multiple effector proteins and growth factors, such as TGF-β, CTGF, and IL-6. Activation of TGF-β accumulates higher ECM matrix-like Col1 and α-SMA both on the outside and inside of the cell membrane. Therefore, modalities that can induce apoptosis signaling pathways could target cancer and fibrosis treatment. Navitoclax (NAVI) is a BCL-2 and BCL-xL inhibitor small molecule approved by FDA for cancer treatment. BCL-2 and BCL-xL are anti-apoptotic proteins, and inhibition of these proteins results in the induction of apoptosis. To achieve non-invasive and targeted local delivery, we utilized an ionic liquid composed of Choline bicarbonate and Octanoic Acid (COA) to enhance topical transportation of the small hydrophobic molecules like NAVI. The COA-mediated topical distribution of NAVI improved drug transportation through the skin barrier and retained the drug to stay longer in the deeper skin layers. COA/NAVI had a better cancer-cell killing selectivity than orally administered NAVI, with minor inflammation to healthy human skin cells. In vivo experiments show that it effectively treats melanoma without causing irritation or systemic absorption. The COA/NAVI combination triggered apoptosis in the mouse xenograft model and provided a safe and effective topical administration for the treatment of melanoma. COA-mediated topical delivery of NAVI also heals preexisting fibrosis in a rat model of scleroderma cutaneous fibrosis by triggering myofibroblast death. Using a BH3 profiling assay, we show that the extent of apoptosis induced by BH3 mimetic drugs correlates with their mitochondrial priming in dermal fibroblasts derived from scleroderma patients, implying that BH3 profiling could predict apoptotic responses of the fibroblasts to BH3 mimetic medicines in scleroderma patients. In scleroderma, topical application of COA/NAVI targeting myofibroblast anti-apoptotic proteins combined with BH3 mimetic medications reduces fibrotic indicators in mouse models. Additionally, topical administration of NAVI combined with COA reduced thrombocytopenia toxicity, which is the biggest challenge for the clinical translation of NAVI. Finally, β-Glucan mediated oral delivery of NAVI induced apoptosis in the paclitaxel resistance tumor model. NAVI can kill paclitaxel-resistant cells by overcoming the barrier associated with the tumor. We demonstrated plausible molecular reasons for the link between paclitaxel medication resistance and how to inhibit MDA MB 231 PTXR tumor growth using a BCL-2 inhibitor in this pilot investigation. In a C57BL/6 mouse model, tumor inhibition and drug resistance reversal were tested using -Glucan mediated Navitoclax oral administration. We have evaluated the hypothesis in both in vitro 2D and in vivo solid tumor models. Both findings confirm that targeting anti-apoptotic proteins, such as BCL-2 and BCL-xL, has the clinical translational capability for skin melanoma and fibrosis treatment.

Language

en

Provenance

Recieved from ProQuest

File Size

p.

File Format

application/pdf

Rights Holder

Mohammad Nurul Huda

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