Doctor of Philosophy, The Ohio State University, 2023, Pharmacy

Triple-negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases, yet it disproportionately contributes to 35% of breast cancer deaths. In addition, chemotherapy resistance is a significant challenge in TNBC treatment. In this study, we aimed to identify potential synthetic lethal targets for cisplatin/doxorubicin treatment in TNBC and investigate the potential of a cell-death double knock-out library to discover synergistic lethal gene pairs for TNBC therapy. Initially, we identified the MDA-MB-231 cell line as the most representative model for TNBC chemotherapy-poor responders by comparing genomic profiles from TNBC cell lines and patient samples. We then conducted a genome-wide CRISPR-Cas9 screen and RNAseq analysis in MDA-MB-231 cells. Our analysis confirmed the involvement of known essential genes in DNA damage repair and regulation of DNA replication pathways, such as BCL2L1, ATM, CDC25B, and NBN, in sensitizing cells to cisplatin/doxorubicin. Moreover, we identified hundreds of previously unrecognized genes and pathways related to DNA repair, G2/M DNA damage checkpoint, AMPK signaling, and mTOR signaling. The observed differences between transcriptomic responses and essential pathways from the CRISPR screen suggest a complex regulatory system in the cellular response to DNA-damaging drugs. By integrating various data analysis methods and biological experimental approaches, we pinpointed several promising genes, such as MCM9 and NEPPS, which could serve as potential drug targets to overcome chemoresistance. We also utilized our lab's custom CRISPR double knock-out library, which leverages the XDeathDB database for candidate gene selection. This comprehensive platform provides insights into 12 cell death modes and 149 cell death hallmark genes. We aim to create a cell-death double knock-out library using these genes and perform double knock-out screening on MDA-MB-231 cells. The identified synergistic lethal gene pairs may serve as potentia (open full item for complete abstract)

Committee: Lang Li (Advisor) Subjects: Bioinformatics; Pharmacology; Pharmacy Sciences

PHD, Kent State University, 2022, College of Arts and Sciences / Department of Chemistry and Biochemistry

Each year, about 250,000 women are diagnosed with ovarian cancer in the US, and approximately half of these patients die within 5 years after their initial diagnosis. This problem is attributed to the development of drug resistance to the standard platinum (Pt)- based chemotherapy. Cancer stem cell (CSC) theory developed recently holds a promising explanation to this problem and serves as a guide to search for a proper solution. CSCs are a small population of cancer cells that have tumorigenic ability. According to the most recent studies, mitochondria of CSCs are one of the most promising targets towards eliminating CSCs. Although, some mitochondria targeting compounds that eradicate CSCs have been developed, they have major drawbacks like lower pharmacokinetics and higher systematic toxicity that avoid them going for clinical stages. In this study, we present Mitochondria targeting Pt(IV) compounds with fatty acid like structure that effectively target and eliminate CSCs. This structure type utilizes a transmembrane protein CD36 for higher cellular uptake. Ovarian cancer that are resistant to conventional Pt therapeutics, shown to have higher expression of CD36 and so will result in higher accumulation of fatty acid like Pt(IV) compounds. However, some of the Pt compounds will accumulate into healthy cells and may result in some systematic toxicity. As a promising strategy to lower the systematic toxicity, photoactivatable Pt(IV) prodrugs approach is considered. Reactivity of fatty acid like Pt(IV) compounds will be hindered by conjugating suitable dye molecules into the structure making them inactive. By irradiating at the tumor site, active form of the Pt compound will be released to have toxic effects. Controlled activation of fatty acid like Pt(IV) conjugates by UV-visible radiation was achieved during the preliminary work. In order to irradiate with lower energy and to have deeper tissue penetration, NIR (near-infrar (open full item for complete abstract)

Committee: Yaorong Zheng (Advisor); Songping Huang (Committee Member); Srinivasan Vijayaraghavan (Committee Member); Woo-Yang Kim (Committee Member); Mietek Jaroniec (Committee Member) Subjects: Biochemistry; Chemistry

Doctor of Philosophy (PhD), University of Toledo, 2020, Biomedical Sciences (Cancer Biology)

Chemoresistance is a major clinical concern in triple-negative breast cancer (TNBC) patients, leading to minimal residual disease and tumor relapse. Intrinsic chemoresistance is mediated by the surviving breast cancer stem-like cells (BCSCs) that self-renew and undergo multilineage differentiation to repopulate into a heterogeneous tumor. BCSCs are not only intrinsically chemo/radio resistant, but can also interconvert between BCSCs and bulk tumor cells. In addition to intrinsic therapy resistance, cancer cells can also acquire resistance when they are gradually exposed to therapy, which is the usual course of a treatment regimen. During this process, cancer cells continuously adapt and rewire or reprogram themselves and their microenvironment by upregulating drug transporter proteins and survival factors for their sustenance. Therefore, it is imperative to identify novel molecular targets and develop therapeutic strategies that could co-target BCSCs and bulk tumor cells to tackle both, intrinsic and acquired chemoresistance. Many oncogenic signaling pathways converge at the eukaryotic protein translation initiation machinery, the eIF4F complex which plays a key role in regulating the translatome. This complex plays a critical role in translation of several oncogenic mRNAs implicated in cellular proliferation, invasion, metastasis and chemoresistance. In our previous study, we demonstrated that the mRNA helicase eIF4A1 of the eIF4F complex, serves as a vulnerable node in inducing cell-death in TNBC cells. In our current study, we hypothesized that targeting eIF4A1 could be used as a strategy to overcome breast cancer chemoresistance. We developed two model systems; BCSCs and paclitaxel-resistant cells, reflective of intrinsic and acquired chemoresistance. Through pharmacological (Rocaglamide A) and genetic (CRISPR-Cas9) targeting of eIF4A1, we observed a statistically significant reduction in the self-renewal ability, pluripotency factors and drug transporter expres (open full item for complete abstract)

Committee: Dayanidhi Raman (Advisor); Kathryn Eisenmann (Committee Member); Saori Furuta (Committee Member); Nagalakshmi Nadiminty (Committee Member); Amit Tiwari (Committee Member) Subjects: Biomedical Research

Doctor of Philosophy, Case Western Reserve University, 2018, Pathology

Breast cancer is the most common malignancy and second most common cause of cancer-related death in women, a clinical challenge exasperated by the lack of targeted therapies for metastasis, the most deadly component of breast cancer. Although the molecular mechanisms underpinning the dissemination of primary breast cancer cells to distant tissues remain incompletely understood, long noncoding RNAs (lncRNAs) have emerged as potent regulators of breast cancer development and progression, including the metastatic spread of disease. Through in silico and biological analyses, we identified a novel lncRNA, BMP/OP-Responsive Gene (BORG), whose expression directly correlates with aggressive breast cancer phenotypes, as well as with metastatic competence and disease recurrence in multiple clinical breast cancer patient cohorts. Mechanistically, BORG elicits the metastatic outgrowth of latent breast cancer cells by promoting the localization and transcriptional repressive activity of TRIM28, which binds BORG and induces substantial alterations in carcinoma proliferation and survival. Moreover, inhibiting BORG expression in metastatic breast cancer cells impedes their metastatic colonization of the lungs of mice, implying that BORG acts as a novel driver of the genetic and epigenetic alterations that underlie the acquisition of metastatic and recurrent phenotypes by breast cancer cells. Interestingly, the BORG-dependent transcriptome demonstrates enhanced signaling through survival and viability pathways, as well as decreased activation of cell death pathways. Accordingly, we determined that BORG expression is broadly promoted by environmental and chemotherapeutic stresses, a transcriptional response that facilitates the survival of breast cancer cells. These effects rely upon a BORG-induced induction of NF- B signaling as part of a feed-forward NF- B signaling loop, as well as its ability to bind and activate RPA1. Taken together, our mechanistic insights into BORG-m (open full item for complete abstract)

Committee: William Schiemann (Advisor); Hannah Gilmore (Committee Chair); Saba Valadkhan (Committee Member); Mark Jackson (Committee Member); Goutham Narla (Committee Member) Subjects: Oncology; Pathology

PhD, University of Cincinnati, 2008, Medicine : Cell and Molecular Biology

Chemotherapy is mainstay treatment for cancer patients, but unfortunately many tumors are resistant to therapy. Much research now focuses on identifying mechanisms that contribute to chemoresistance. The importance of such research lies in the fact that no other treatment has proven as effective in controlling cancer metastasis and preventing tumor recurrence. This thesis focuses on: 1) identifying a cellular model appropriate for studying chemoresistance in liposarcoma and 2) understanding the role of endogenous hormones, such as prolactin (PRL) and estradiol (E2), as well as the endocrine disruptor bishpenol A (BPA), in affecting anti-cancer drug efficacy in breast cancer cells. Project 1: Our first goal was to compare the responsiveness of our LS14 liposarcoma cell line and SW872 liposarcoma cells to anti-cancer drugs and explore the mechanism(s) underlying chemoresistance. Using complementary assays for cell viability and apoptosis, we found that LS14 cells are much less respsonsive to anti-cancer drugs and have higher expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL. In addition, LS14 cells are also tumorigenic in nude mice. Project 2: The role of PRL as a survival hormone led to the hypothesis that PRL protects breast cancer cells from chemotherapy. We found that low dose PRL antagonized the cytotoxic effects of various anti-cancer drugs and prevented cisplatin-induced cell cycle arrest and apoptosis. γ-H2AX staining and mass spectroscopy reveal less DNA damage and less cisplatin bound to DNA in the presence of PRL. Glutathione s-transferase, which sequesters cisplatin in the cytoplasm, was dramatically increased by PRL; an effect abrogated by Jak and MAPK inhibitors. PRL did not antagonize cisplatin or prevent its binding to DNA in the presence of a GST inhibitor. Project 3: Our third study focused on the roles of BPA and E2 in chemoresistance in breast cancer cells. BPA and E2 confer resistance to various anti-cancer drugs in both ERα-positive an (open full item for complete abstract)

Committee: Nira Ben-Jonathan PhD (Committee Chair); Arthur Buckley PhD (Committee Member); Kathleen Goss PhD (Committee Member); Nelson Horseman PhD (Committee Member); Peter Stambrook PhD (Committee Member) Subjects: Cellular Biology

Doctor of Philosophy, The Ohio State University, 2005, Pharmacy

Our laboratory reported that acidic and basic fibroblast growth factors (aFGF/bFGF, FGFs) confer broad-spectrum chemoresistance in solid tumors. The four studies in this dissertation tested the hypothesis that the combination of these two growth factors offers broad-spectrum protection against chemotherapy-induced alopecia (CIA). In chapter 2, we established and characterized CIA animal models by different chemotherapeutic agents representing four major classes of anticancer drugs, i.e., alkylators (cyclophosphamide), topoisomerase 2 inhibitors (doxorubicin), antimicrotubules (paclitaxel), and antimetabolites (cytosine arabinoside, or ara-c). In chapter 3, we evaluated the pharmacodynamic endpoints in the two CIA animal models. The data showed that the chemotherapeutic agents induced dermal layer shrinkage, reduced hair bulb diameter, shortened hair follicle length, altered hair bulb matrix cell proliferative activity and induced hair follicular apoptosis. Paclitaxel induced disruptions of hair follicle melanogenesis in the black C57BL-6 mice resulting in relocation of melanin to ectopic hair bulb locations. The collective data indicated that hair bulb matrix and outer root sheath (ORS) were the two major targets of chemotherapy in hair follicles. In chapter 4, we evaluated the protective effect of subcutaneous FGFs against CIA in the two animal models. The results showed that FGFs offered broad-spectrum protection against CIA by all four chemotherapeutic agents. In addition, FGFs accelerated the hair regrowth after CIA by high dose cyclophosphamide. Chapter 5 further investigated the protective effect of topical FGFs dissolved in 75% dimethyl sulfoxide (DMSO) against CIA. The data showed that topical FGFs reversed CIA by all four chemotherapeutic agents in the animal models. The data further showed that no or insignificant exposure of bFGF after subcutaneous or topical delivery of bFGF, suggesting that applying FGFs to the scalp will not compromise the efficacy of (open full item for complete abstract)

Committee: Jessie Au (Advisor) Subjects:

Doctor of Philosophy in Medical Sciences (Ph.D.), University of Toledo, 2006, College of Graduate Studies

Cytotoxic and targeted therapies are ineffective in the majority of individuals diagnosed with bronchogenic carcinoma, due in part, to alterations in genes that regulate cell proliferation control and apoptosis. In order to develop more effective therapies, and better utilize existing therapies, it is necessary to understand how inter-individual variation in gene expression contributes to therapeutic response, so that each individual receives the appropriate medication at the appropriate dose. First, we found extensive inter-individual variation in the expression of the cyclin-dependent kinase inhibitor, p21, which was attributable to upstream transcription factors E2F1 and p73 in bronchogenic carcinoma cells, but not normal bronchial epithelial cells. Second, we hypothesized that bronchogenic carcinoma cell lines with high expression of E2F1 and p73, and wild type p53, would have a defect in their apoptosis pathway, and therefore, would be resistant to chemotherapy. However, high expression of E2F1 and p73 as well as c-myc, was associated with spontaneous apoptosis and chemosensitivity, but induction of p53 and p21 was associated with small increases in apoptosis and chemoresistance. From these results we identified an interactive transcript abundance index (ITAI) in the form of a ratio, [c-myc*p73a]/[p21*Bcl-2] which was correlated with response to CPT-11 in bronchogenic carcinomas and other tissues, regardless of p53 status. These studies lead to an additional hypothesis, that inter-individual variation in expression of p53 and related genes in peripheral blood leukocytes (PBLs) could predict cytotoxicity to chemotherapy. In these studies, variation in gene expression was observed between two individuals that showed vast differences in lymphocyte counts following chemotherapy. In summary, we have identified at set of genes that contribute to cell proliferation control and apoptosis in normal and malignant cells, and may collectively predict chemoresistance or cyt (open full item for complete abstract)

Committee: James Willey (Advisor) Subjects: