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Description
The majority of chronic myeloid leukemia (CML) and some of acute lymphocytic leukemia (ALL) cases are associated with possessing the BCR-Abl fusion protein from an oncogenic translocation, resulting in a constantly active form of Abl and rapid proliferation. CML and ALL cells that possess the BCR-Abl fusion protein are known as Philadelphia chromosome positive (Ph+). Currently, Imatinib (selective Abl inhibitor) is used as therapy against CML and ALL. However, some patients may have malignancies which show resistance to Imatinib. Previous work displays that the transformation of progenitor B cells with the v-Abl oncogene of Abelson murine leukemia virus results in cell cycle progression, rapid proliferation, and potentially malignant transformation while preventing any further differentiation. Progenitor B cells transformed with the temperature-sensitive form of the v-Abl oncogene have served as a model to study cellular response to Imatinib treatment. After some manipulation, very few cells were forced to progress to malignancy, forming tumor in vivo. These cells were no long sensitive to v-Abl inactivation, resembling the Imatinib resistant ALL. Autophagy is the process by which proteins and organelles are broken-down and recycled within the eukaryotic cell and has been hypothesized to play a part in cancer cell survival and drug-resistance. LC3 processing is a widely accepted marker of autophagy induction and progression. It has also been shown that Imatinib treatment of Ph+ leukemia can induce autophagy. In this study, we examined the autophagy induction in response to v-Abl inactivation in a Ph+-B-ALL cell model that shows resistance to Imatinib. In particular, we wonder whether the tumor cell line resistant to v-Abl inactivation may acquire a high level of autophagy to become resistant to apoptosis induced by v-Abl inactivation, and thus become addicted to autophagy. Indeed, this tumor cell line displays a high basal levels of LC3 I and II expression, regardless of v-Abl activity. We further demonstrated that inhibition of the autophagy pathway enhances the tumor line's sensitivity to Imatinib, resulting in cell cycle arrest and massive apoptosis. The combination of autophagy and Abl inhibitions may serve as an effective therapy for BCR-Abl positive CML.
ContributorsArkus, Nohea (Author) / Chang, Yung (Thesis advisor) / Kusumi, Kenro (Committee member) / Lake, Douglas (Committee member) / Jacobs, Bertram (Committee member) / Arizona State University (Publisher)
Created2011
Description
As advanced as current cancer therapeutics are, there are still challenges that need to be addressed. One of them is the non-specific killing of normal cells in addition to cancerous cells. Ideal cancer therapeutics should be targeted specifically toward tumor cells. Due to the robust self-assembly and versatile addressability of DNA-nanostructures, a DNA tetrahedron nanostructure was explored as a drug carrier. The nanostructure can be decorated with various molecules to either increase immunogenicity, toxicity, or affinity to a specific cell type. The efficiency of the specific binding and internalization of the chosen molecules was measured via flow cytometry. Using a murine B cell lymphoma as the model system, several targeting molecules have been evaluated for their specific binding and induced internalization of DNA nanostructures, including an anti-Igκ antibody, an idiotype-binding peptide, and a g-quadruplex nucleolin specific aptamer. It was found that adding the anti-Igκ antibody appeared to provide increased binding and facilitated cellular internalization. Also, it was found that the presence of CpG appeared to aid in the binding of nanostructures decorated with other molecules, as compared to nanostructures without CpG. The g-quadruplex aptamer thought to specifically bind cancer cells that overexpress nucleolin was tested and found to have better binding to cells when linked to the nanostructure than when alone. The drug doxorubicin was used to load the DNA-nanostructure and attempt to inhibit cancer cell growth. The DNA-nanostructure has the benefit of being self-assembled and customizable, and it has been shown to bind to and internalize into a cancer cell line. The next steps are to test the toxicity of the nanostructure as well as its specificity for cancerous cells compared to noncancerous cells. Furthermore, once those tests are completed the structure’s drug delivery capacity will be tested in tumor bearing mice. The DNA-nanostructure exhibits potential as a cancer specific therapeutic.
ContributorsGomez, Amber Marie (Author) / Chang, Yung (Thesis director) / Anderson, Karen (Committee member) / Liu, Xiaowei (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / School of Molecular Sciences (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The properties of adjuvants to stimulate an immune response to treat cancer has sparked a major area of research in the field of immunotherapy. Given the presence of multiple RNA sensors in mammalian host cells for eliciting innate immunity, synthetic RNA nanostructures present a unique opportunity for adjuvant exploration. While RNA nanostructures are organic and biocompatible in nature than other adjuvants, they could be tailored to have desired structural stability and functional diversity for in vivo application. In this study, a rectangular RNA origami nanostructure was designed to contain double-stranded RNA motifs and possess high structural stability. Using in vitro assays, RNA origami was shown to stimulate the toll-like receptor 3 (TLR3) signaling pathway, which has been reported to activate antigen presenting cells (APCs), natural killer (NK) cells, cluster of differentiation 8 (CD8) T-cells, and the secretion of proinflammatory cytokines. To explore RNA origami as an adjuvant for cancer immunotherapy, intraperitoneal administration of a murine colon cancer cell line (CT26) was used as a model system to mimic peritoneal metastasis (PM), in which RNA origami was investigated for its activities in mitigating PM tumor microenvironment and improving anti-tumor immunity. Given the poor outcome of the patients with PM and urgent need for new interventions, this study aims to translate the adjuvant activities of RNA origami demonstrated in vitro into potent anti-cancer immunotherapeutics. Here, it was shown that multiple intraperitoneal injections of RNA origami could inhibit tumor growth, leading to a significant delay and/or regression of metastatic tumor growth in the peritoneum. Furthermore, tumor-free mice, after being treated with RNA origami, were also resistant to a second challenge of tumor cells, indicating the development of the adaptive anti-tumor immunity. This immunity is dependent on T-cells since nude mice succumbed to tumor growth with or without RNA origami treatment. Thus, RNA-origami can function as an adjuvant to activate the innate immunity and subsequently the adaptive anti-tumor immunity, leading to tumor regression. Conceivably, RNA origami could be explored as an immunotherapeutic agent to improve the disease outcome of patients with peritoneal metastasis and peritoneal carcinogenesis.
ContributorsRodriguez del Villar, Ryan Luis (Author) / Chang, Yung (Thesis advisor) / Liu, Xiaowei (Committee member) / Qi, Xiaodong (Committee member) / Arizona State University (Publisher)
Created2018
Cancer autoantibody biomarker discovery and validation using nucleic acid programmable protein array
Description
Currently in the US, many patients with cancer do not benefit from the population-based screening, due to challenges associated with the existing cancer screening scheme. Blood-based diagnostic assays have the potential to detect diseases in a non-invasive way. Proteins released from small early tumors may only be present intermittently and get diluted to tiny concentrations in the blood, making them difficult to use as biomarkers. However, they can induce autoantibody (AAb) responses, which can amplify the signal and persist in the blood even if the antigen is gone. Circulating autoantibodies is a promising class of molecules that have potential to serve as early detection biomarkers for cancers. This Ph.D thesis aims to screen for autoantibody biomarkers for the early detection of two deadly cancer, basal-like breast cancer and lung adenocarcinoma. First, a method was developed to display proteins in both native and denatured conformation on protein array. This method adopted a novel protein tag technology, called HaloTag, to covalently immobilize proteins on glass slide surface. The covalent attachment allowed these proteins to endure harsh treatment without getting dissociated from slide surface, which enabled the profiling of antibody responses against both conformational and linear epitopes. Next, a plasma screening protocol was optimized to significantly increase signal to noise ratio of protein array based AAb detection. Following this, the AAb responses in basal-like breast cancer were explored using nucleic acid programmable protein arrays (NAPPA) containing 10,000 full-length human proteins in 45 cases and 45 controls. After verification in a large sample set (145 basal-like breast cancer cases / 145 controls / 70 non-basal breast cancer) by ELISA, a 13-AAb classifier was developed to differentiate patients from controls with a sensitivity of 33% at 98% specificity. Similar approach was also applied to the lung cancer study to identify AAbs that distinguished lung cancer patients from computed-tomography positive benign pulmonary nodules (137 lung cancer cases, 127 smoker controls, 170 benign controls). In this study, two panels of AAbs were discovered that showed promising sensitivity and specificity. Six out of eight AAb targets were also found to have elevated mRNA level in lung adenocarcinoma patients using TCGA data. These projects as a whole provide novel insights on the association between AAbs and cancer, as well as general B cell antigenicity against self-proteins.
ContributorsWang, Jie (Author) / LaBaer, Joshua (Thesis advisor) / Anderson, Karen S (Committee member) / Lake, Douglas F (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2015