Browsing by Author "Yeh, Elizabeth"

Now showing 1 - 7 of 7
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    Characterization of a Novel Hunk Inhibitor in HER2+ Breast Cancer
    (2024-07) Dilday, Tinslee Y.; Yeh, Elizabeth; Fehrenbacher, Jill; Brustovetsy, Nickolay; Safa, Ahmad; Sankar, Uma
    Human Epidermal Growth Factor Receptor 2 (HER2)-targeted agents have proven to be effective, however, the development of resistance to these agents has become an obstacle in treating HER2+ breast cancer. Prior evidence implicates Hormonally Upregulated Neu-associated Kinase (HUNK) as an anti-cancer target for primary and resistant HER2+ breast cancers. An inhibitor Staurosporine (STU) has been identified as a HUNK inhibitor in HER2+ breast cancer. While STU was determined as a promising tool for inhibiting HUNK, it is a broad-spectrum kinase inhibitor and has not moved forward clinically. Therefore, identifying a more selective inhibitor of HUNK could be critical for targeting HUNK in HER2+ breast and understanding mechanisms by which HUNK promotes resistance to HER2-inhibitors. Specifically, HUNK has been implicated in promoting autophagy as a resistance mechanism in HER2+ breast cancer. Previously, we have identified that HUNK binds and phosphorylates an autophagy inhibitory protein, Rubicon, at Serine (S) 92 in 293T cells. This phosphorylation event causes Rubicon to switch to being an autophagy promoter. However, the role that Rubicon S92 plays in HER2+ breast cancer has yet to be examined. In this study, a novel inhibitor of HUNK is characterized alongside Rubicon S92 phosphorylation. This study establishes that HUNK-mediated phosphorylation of Rubicon at S92 promotes tumorigenesis in HER2/neu+ breast cancer. HUNK inhibition prevents S92 Rubicon phosphorylation in HER2/neu+ breast cancer models and inhibits both autophagy and tumorigenesis. This study characterizes a downstream phosphorylation event as a measure of HUNK activity and identifies a novel HUNK inhibitor that has meaningful efficacy toward HER2+ breast cancer.
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    Elucidating the Role of the Essential Kinase TgGSK in the Human Parasite Toxoplasma Gondii
    (2025-02) Krueger, Amanda; Yeh, Elizabeth; Arrizabalaga, Gustavo; Sullivan, William; Nass, Richard; Aoki, Scott
    Toxoplasma gondii is an intracellular parasite that infects nearly a third of the world’s human population. While infection is largely asymptomatic in an immunocompetent host, Toxoplasma infection in immunocompromised or immunosuppressed individuals can lead to toxoplasmosis, which can include brain lesions and lead to death. Similarly, toxoplasmosis can result in birth defects, brain swelling, and blindness of a developing fetus in the case of a congenital infection. With minimal treatments for toxoplasmosis available, it is crucial to study parasite-specific processes that could be potential drug targets for the treatment of toxoplasmosis. Toxoplasma gondii divides through a unique process known as endodyogeny, where two daughter parasites are formed within a mother. In this study, we investigated a novel protein called TgGSK that is crucial for proper parasite division. Experiments reveal that TgGSK changes its localization within the parasite dependent on the stage of division. Knockdown of TgGSK causes abnormal division phenotypes and causes Toxoplasma to be unable to complete its propagation cycle. We determined through microscopy and phosphoproteomics that TgGSK may play its role in parasite division through an interaction with the centrosome, an organelle which is a main feature of cell division in many organisms. Our findings suggest that TgGSK also regulates messenger RNA processing. Finally, our study suggests that TgGSK is regulated and stabilized through acetylation from the GCN5b lysine acetyltransferase complex. Taken together, we have performed an in-depth study of the functional role of the essential protein TgGSK in Toxoplasma gondii. This and future studies have potential to demonstrate that TgGSK is a parasite-specific drug target for the therapeutic treatment of toxoplasmosis.
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    HUNK as an Immune Regulator of Triple Negative Breast Cancer
    (2024-05) Ramos Solis, Nicole; Yeh, Elizabeth; Arrizabalaga, Gustavo; Fehrenbacher, Jill; Cook-Mills, Joan; Jerde, Travis J.
    Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Unlike other breast cancer types, TNBC tumors do not respond to endocrine therapy, and standardized treatment protocols for TNBC are currently unavailable. TNBC is recognized as a more metastatic, aggressive, and immunogenic subtype of breast cancer, rendering it to be more receptive to immunotherapy. Among the immune cell populations abundant in TNBC tumors, tumor-associated macrophages (TAMs) are particularly more prevalent and are particularly known to play a role in cancer metastasis. This work focuses on and investigates the involvement of the protein kinase HUNK in tumor immunity. With the use of gene expression analysis, such as NanoString's nCounter PanCancer Immune Profiling panel, we found that targeting HUNK is associated with alterations in the IL-4/IL-4R cytokine signaling pathway. Experimental analysis and work demonstrated that HUNK kinase activity regulates IL-4 production in mammary tumor cells, and this regulation is dependent on STAT3. Furthermore, in vivo, analysis shows that HUNK-dependent control of IL-4 secretion from tumor cells leads to the polarization of macrophages into an M2-like phenotype, and consequently, IL-4 induction promotes cancer metastasis and prompts macrophage's metastatic capacities. These findings underscore HUNK as a potential therapeutic target for mitigating TNBC metastasis by modulating the TAM population.
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    HUNK Signaling in Metastatic Breast Cancer
    (Impact Journals, 2020-05-05) Dilday, Tinslee; Ramos, Nicole; Yeh, Elizabeth; Pharmacology and Toxicology, School of Medicine
    Once metastatic disease has occurred, there is no cure for breast cancer. Consequently, identifying factors that promote and support breast cancer metastasis is critical for understanding how to pharmacologically target this process. Hormonally up-regulated neu-associated kinase (HUNK) is a serine/threonine protein kinase related to the sucrose non-fermenting-1 (Snf-1)/5’ adenosine monophosphate-activated protein kinase (AMPK) family of kinases. HUNK has been found to play a role in breast cancer metastasis. However, conflicting reports indicate HUNK is a metastasis promoting factor as well as an inhibiting factor. Our group recently provided evidence that supports the conclusion that HUNK is a metastasis promoting factor by showing that HUNK regulates breast cancer metastasis through phosphorylation of EGFR. Here, we summarize our findings and discuss their implications toward pharmacological targeting of HUNK in breast cancer.
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    Pharmacological Depletion of Fibrinogen Suppresses the Growth of Primary Tumors and Metastasis of Pancreatic Ductal Adenocarcinoma (PDAC)
    (2024-08) Chowdhury, Nayela Nabiha; Fishel, Melissa L.; Yeh, Elizabeth; Pollok, Karen; Manchanda, Naveen; Jerde, Travis J.
    PDAC is a highly metastatic disease often linked to the dysregulated activation of both coagulation and fibrinolytic systems. Clinically, patients show elevated plasma fibrinogen levels, particularly in those with distant metastasis. The presence of systemic fibrinogen plays a crucial role in shaping the complex tumor microenvironment characteristic of PDAC, evidenced by the excessive deposition of its active substrate, fibrin, in PDAC tumors. To investigate its contribution to disease progression, fibrinogen was significantly depleted from the TME in multiple PDAC patient-derived xenograft (PDX) models, and the impact on tumor growth and metastasis was followed. In an aggressive, metastatic orthotopic Pa03C model, Fib depletion using antisense oligonucleotide (ASO) treatment markedly decreased the size of primary pancreatic tumors and subsequent spontaneous metastasis to the liver. Following implantation of tumor chunks (PDX21) from a patient with high Fib staining, Fib ASO treatment significantly diminished growth of primary tumors. Using a third orthotopic model (PDX33) and lipid nanoparticle (LNP)-encapsulated-siRNA to deplete the fibrinogen--chain, tumor growth was significantly reduced compared to control. This confirms that Fib deposition within the tumor microenvironment (TME) is an important driver of disease progression. Mechanistically, global proteomics revealed a remarkable upregulation of matrisome and extracellular matrix (ECM)-associated proteins, indicating that the reduction in primary orthotopic Pa03C tumors was associated with fibrin-mediated TME remodeling. Loss of fibrin matrices led to enhanced collagen, laminin, fibronectin and emilin1 deposition, and increased recruitment of collagen-producing αSMA+ myofibroblasts. Notably, our data suggests that fibrinogen depletion altered the ECM composition, inducing TME remodeling which led to stiffer tumors that are less metastatic. To further interrogate the role of fibrinogen in mediating metastasis, we employed an experimental metastasis model to study the colonization of tumor cells in the liver in the absence of fibrinogen. In this model, fibrinogen depletion did not impede the colonization of Pa03C cells, suggesting that fibrinogen does not mediate the colonization of tumor cells in the cascade of events for liver metastasis and is likely involved in one of the other steps of metastasis. Collectively, our data showed that pharmacologically reducing systemic fibrinogen levels impeded tumor growth and metastasis by remodeling the TME.
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    Polo-like kinase 1 (Plk1) inhibition synergizes with taxanes in triple negative breast cancer
    (Public Library of Science, 2019-11-21) Giordano, Antonio; Liu, Yueying; Armeson, Kent; Park, Yeonhee; Ridinger, Maya; Erlander, Mark; Reuben, James; Britten, Carolyn; Kappler, Christiana; Yeh, Elizabeth; Ethier, Stephen; Pathology and Laboratory Medicine, School of Medicine
    Within triple negative breast cancer, several molecular subtypes have been identified, underlying the heterogeneity of such an aggressive disease. The basal-like subtype is characterized by mutations in the TP53 gene, and is associated with a low pathologic complete response rate following neoadjuvant chemotherapy. In a genome-scale short hairpin RNA (shRNA) screen of breast cancer cells, polo-like kinase 1 (Plk1) was a frequent and strong hit in the basal breast cancer cell lines indicating its importance for growth and survival of these breast cancer cells. Plk1 regulates progression of cells through the G2-M phase of the cell cycle. We assessed the activity of two ATP-competitive Plk1 inhibitors, GSK461364 and onvansertib, alone and with a taxane in a set of triple negative breast cancer cell lines and in vivo. GSK461364 showed synergism with docetaxel in SUM149 (Combination Index 0.70) and SUM159 (CI, 0.62). GSK461364 in combination with docetaxel decreased the clonogenic potential (interaction test for SUM149 and SUM159, p<0.001 and p = 0.01, respectively) and the tumorsphere formation of SUM149 and SUM159 (interaction test, p = 0.01 and p< 0.001). In the SUM159 xenograft model, onvansertib plus paclitaxel significantly decreased tumor volume compared to single agent paclitaxel (p<0.0001). Inhibition of Plk1 in combination with taxanes shows promising results in a subset of triple negative breast cancer intrinsically resistant to chemotherapy. Onvansertib showed significant tumor volume shrinkage when combined with paclitaxel in vivo and should be considered in clinical trials for the treatment of triple negative cancers.
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    Therapeutic Targeting of BET Proteins in Osteosarcoma
    (2025-03) Riyahi, Niknam; Pollok, Karen; Angus, Steve; Fehrenbacher, Jill; Jerde, Travis; Yeh, Elizabeth
    Osteosarcoma (OS) is an aggressive bone cancer in pediatric, adolescent, and young adult patients with an exceedingly poor prognosis. An area of therapeutic opportunity is that OS exhibits increased oncogenic replication stress (RS), augmenting genome instability and tumor progression. Exploiting RS provides a treatment intervention. Bromodomain and extra-terminal (BET) proteins regulate DNA transcription, replication, and repair. BET inhibitors create an imbalance between transcription and replication kinetics, exacerbating oncogenic RS and increasing cell death. We hypothesized that BET inhibition would decrease OS tumor growth via modulation of gene expression and increased RS. Bivalent BET inhibitor AZD5153 monotherapy significantly suppressed the growth of patient-derived xenografts (PDXs) established from treatment-naïve male and female OS patients. AZD5153-mediated anti-tumor effect correlated with increased γ-H2AX levels, indicative of elevated RS. RNA-sequencing and kinome profiling revealed intra- and inter-tumoral molecular response mechanisms attributable to therapeutic response and potential resistance in BET inhibitor-treated PDX and OS cell lines. Reprogramming of signaling networks involved in DNA damage response, apoptosis, invasion, and Wnt signaling were identified. Combining AZD5153 with salvage agents demonstrated additive-to-synergistic cell growth inhibition in vitro with drug combinations inducing apoptosis. AZD5153 increased DNA-strand breaks that was further enhanced by salvage therapy. In a PDX established from a metastatic lesion of a patient treated with frontline and salvage therapy, a combination of AZD5153 and topotecan was well tolerated and increased survival probability compared to each agent alone. These data suggest that AZD5153 alone or in combination with low-dose salvage therapy holds promise as an efficacious treatment strategy in OS.