Matching Items (10)
Filtering by
- Resource Type: Text
Description
Patients with malignant brain tumors have a median survival of approximately 15 months following diagnosis, regardless of currently available treatments which include surgery followed by radiation and chemotherapy. Improvement in the survival of brain cancer patients requires the design of new therapeutic modalities that take advantage of common phenotypes. One such phenotype is the metabolic dysregulation that is a hallmark of cancer cells. It has therefore been postulated that one approach to treating brain tumors may be by metabolic alteration such as that which occurs through the use of the ketogenic diet (KD). The KD is high-fat, low-carbohydrate diet that induces ketosis and has been utilized for the non-pharmacologic treatment of refractory epilepsy. It has been shown that this metabolic therapy enhances survival and potentiates standard therapy in mouse models of malignant gliomas, yet the anti-tumor mechanisms are not fully understood.
The current study reports that KetoCal® (KC; 4:1 fat:protein/carbohydrates), fed ad libitum, alters hypoxia, angiogenic, and inflammatory pathways in a mouse model of glioma. Tumors from animals maintained on KC showed reduced expression of the hypoxia marker carbonic anhydrase 9 (CA IX), a reduction in hypoxia inducible factor 1-alpha (HIF-1α) and decreased activation of nuclear factor kappa B (NF-κB). Animals maintained on KC also showed a reduction in expression of vascular endothelial growth factor receptor 2 (VEGFR2) and decreased microvasculature in their tumors. Further, peritumoral edema was significantly reduced in animals fed the KC and protein analysis showed significantly altered expression of the tight junction protein zona occludens-1 (ZO-1) and the water channeling protein aquaporin-4 (AQP4), both of which have been implicated in malignant processes in glioma, including the formation of peritumoral edema in patients. Taken together the data suggests that KC alters multiple processes involved in malignant progression of gliomas. A greater understanding of the effects of the ketogenic diet as an adjuvant therapy will allow for a more rational approach to its clinical use.
The current study reports that KetoCal® (KC; 4:1 fat:protein/carbohydrates), fed ad libitum, alters hypoxia, angiogenic, and inflammatory pathways in a mouse model of glioma. Tumors from animals maintained on KC showed reduced expression of the hypoxia marker carbonic anhydrase 9 (CA IX), a reduction in hypoxia inducible factor 1-alpha (HIF-1α) and decreased activation of nuclear factor kappa B (NF-κB). Animals maintained on KC also showed a reduction in expression of vascular endothelial growth factor receptor 2 (VEGFR2) and decreased microvasculature in their tumors. Further, peritumoral edema was significantly reduced in animals fed the KC and protein analysis showed significantly altered expression of the tight junction protein zona occludens-1 (ZO-1) and the water channeling protein aquaporin-4 (AQP4), both of which have been implicated in malignant processes in glioma, including the formation of peritumoral edema in patients. Taken together the data suggests that KC alters multiple processes involved in malignant progression of gliomas. A greater understanding of the effects of the ketogenic diet as an adjuvant therapy will allow for a more rational approach to its clinical use.
ContributorsWoolf, Eric C (Author) / Scheck, Adrienne C (Thesis advisor) / Lake, Douglas F (Committee member) / LaBaer, Joshua (Committee member) / Arizona State University (Publisher)
Created2014
Description
The objective of the research presented here was to validate the use of kinetic models for the analysis of the dynamic behavior of a contrast agent in tumor tissue and evaluate the utility of such models in determining kinetic properties - in particular perfusion and molecular binding uptake associated with tissue hypoxia - of the imaged tissue, from concentration data acquired with dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) procedure. Data from two separate DCE-MRI experiments, performed in the past, using a standard contrast agent and a hypoxia-binding agent respectively, were analyzed. The results of the analysis demonstrated that the models used may provide novel characterization of the tumor tissue properties. Future research will work to further characterize the physical significance of the estimated parameters, particularly to provide quantitative oxygenation data for the imaged tissue.
ContributorsMartin, Jonathan Michael (Author) / Kodibagkar, Vikram (Thesis director) / Rege, Kaushal (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2013-12
Description
Oxygen delivery is crucial for the development of healthy, functional tissue. Low tissue oxygenation, or hypoxia, is a characteristic that is common in many tumors. Hypoxia contributes to tumor malignancy and can reduce the success of chemotherapy and radiation treatment. There is a current need to noninvasively measure tumor oxygenation or pO2 in patients to determine a personalized treatment method. This project focuses on creating and characterizing nanoemulsions using a pO2 reporter molecule hexamethyldisiloxane (HMDSO) and its longer chain variants as well as assessing their cytotoxicity. We also explored creating multi-modal (MRI/Fluorescence) nanoemulsions.
ContributorsGrucky, Marian Louise (Author) / Kodibagkar, Vikram (Thesis director) / Rege, Kaushal (Committee member) / Stabenfeldt, Sarah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Osteosarcoma (OS) is the most prevalent primary tumor of bone in the pediatric age group [1]. The long-term cancer free survival has improved in patients with localized cancer; however, less than 20% of patients diagnosed with metastatic disease survive without relapse [2]. While these findings emphasize the urgent need for new therapeutic agents, the lack of understanding of the factors and the tumor microenvironment that lead to therapy resistance in OS has significantly hampered progress towards improved prognosis. Recent clinical reports have shown a negative correlation between tumor hypoxia and overall survival in OS patients [4]. In addition to the up-regulation of hypoxia inducible factors (HIFs), it has been shown that hypoxia can trigger an adaptive response such as the unfolded protein response (UPR) that allows tumor cells to avoid therapy-induced death [3,4,7,10].
Using in vitro experimental models of both SAOS-2 (non-metastatic) and 143-b (metastatic) osteosarcoma cell lines and Western blot analysis, we have demonstrated that basal levels of molecular chaperone BiP (Binding immunoglobulin protein, or GRP-78) and peIF2α (phospho-eukaryotic initiation factor 2 alpha), both markers of the UPR, were higher in SAOS-2 than 143-b cells. We also show that both these markers were further up-regulated upon exposure to hypoxia, as evidenced by the increase in banding intensity in both SAOS-2 and 143-b cells. Furthermore, analysis of another UPR marker, ATF6 (activating transcription factor 6) showed that basal levels of active nuclear ATF6 were slightly higher in SAOS-2 cells than in 143-b cells. However, unlike the other UPR markers these levels were significantly reduced upon exposure to hypoxia (0.1% O2). In addition to hypoxia, treatment with Cisplatin also had similar effects on the expression of aforementioned UPR markers: BiP and peIF2α. We found that the 143-b OS cells were more sensitive to the Cisplatin treatment than the SAOS-2 OS cells, and thus more prone to cell-mediated death.
Our findings shed light on the unknown mechanisms underlying chemotherapeutic drug resistance in osteosarcoma patients. Our research may lead to novel therapies that seek out and destroy the chemoresistant OS cells within the hypoxia core of tumors, thereby preventing survival and metastasis, and ultimately improving the chances of survival amongst OS patients.
Using in vitro experimental models of both SAOS-2 (non-metastatic) and 143-b (metastatic) osteosarcoma cell lines and Western blot analysis, we have demonstrated that basal levels of molecular chaperone BiP (Binding immunoglobulin protein, or GRP-78) and peIF2α (phospho-eukaryotic initiation factor 2 alpha), both markers of the UPR, were higher in SAOS-2 than 143-b cells. We also show that both these markers were further up-regulated upon exposure to hypoxia, as evidenced by the increase in banding intensity in both SAOS-2 and 143-b cells. Furthermore, analysis of another UPR marker, ATF6 (activating transcription factor 6) showed that basal levels of active nuclear ATF6 were slightly higher in SAOS-2 cells than in 143-b cells. However, unlike the other UPR markers these levels were significantly reduced upon exposure to hypoxia (0.1% O2). In addition to hypoxia, treatment with Cisplatin also had similar effects on the expression of aforementioned UPR markers: BiP and peIF2α. We found that the 143-b OS cells were more sensitive to the Cisplatin treatment than the SAOS-2 OS cells, and thus more prone to cell-mediated death.
Our findings shed light on the unknown mechanisms underlying chemotherapeutic drug resistance in osteosarcoma patients. Our research may lead to novel therapies that seek out and destroy the chemoresistant OS cells within the hypoxia core of tumors, thereby preventing survival and metastasis, and ultimately improving the chances of survival amongst OS patients.
ContributorsFaraj, Janine Jean (Author) / Chandler, Douglas (Thesis director) / Sertil, Aparna (Committee member) / Sweazea, Karen (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2014-05
Description
Magnetic resonance imaging (MRI) of changes in metabolic activity in tumors and metabolic abnormalities can provide a window to understanding the complex behavior of malignant tumors. Both diagnostics and treatment options can be improved through the further comprehension of the processes that contribute to tumor malignancy and growth. By detecting and disturbing this activity through personalized treatments, it is the hope to provide better diagnostics and care to patients. Experimenting with multicellular tumor spheroids (MCTS) allows for a rapid, inexpensive and convenient solution to studying multiple in vitro tumors. High quality magnetic resonance images of small samples, such as spheroid, however, are difficult to achieve with current radio frequency coils. In addition, in order for the information provided by these scans to accurately represent the interactions and metabolic activity in vivo, there is a need for a perfused vascular network. A perfused vascular network has the potential to improve metabolic realism and particle transport within a tumor spheroid. By creating a more life-like cancer model and allowing the progressive imaging of metabolic functions of such small samples, a better, more efficient mode of studying metabolic activity in cancer can be created and research efforts can expand. The progress described in this paper attempts to address both of these current shortcomings of metabolic cancer research and offers potential solutions, while acknowledging the potential of future work to improve cancer research with MCTS.
ContributorsTobey, John Paul (Author) / Kodibagkar, Vikram (Thesis director) / Sadleir, Rosalind (Committee member) / Barrett, The Honors College (Contributor)
Created2016-12
Description
A tumor is a heterogeneous combination of proliferating tumor cells, infiltrating immune cells and stromal components along with a variety of associated host tissue cells, collectively termed the tumor microenvironment (TME). The constituents of the TME and their interaction with the host organ shape and define the properties of tumors and contribute towards the acquisition of hallmark traits such as hypoxia. Hypoxia imparts resistance to cancer from chemotherapy and radiotherapy due to the decreased production of reactive oxygen species and also promotes angiogenesis, malignant progression and metastasis. It also provides a powerful physiological stimulus that can be exploited as a tumor-specific condition, allowing for the rational design of anticancer hypoxia-activated pro-drugs (HAP). Accurate evaluation of tumor oxygenation in response to therapeutics interventions at various stages of growth should provide a better understanding of tumor response to therapy, potentially allowing therapy to be tailored to individual characteristics. The primary goal of this research was to investigate the utility of prospective identification of hypoxic tumors, by two different Magnetic Resonance Imaging (MRI) based oximetry approaches, in successful treatment with hypoxia activated therapy. In the present study, I report the utility of these two techniques 1) PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) and 2) use of a hypoxia binding T1 contrast agent GdDO3NI in reporting the modulations of hypoxia pre and post hypoxia activated therapies in pre-clinical models of cancer. I have performed these studies in non-small cell lung cancer (NSCLC) and epidermoid carcinoma (NCI-H1975 and A431 cell lines, respectively) as well as in patient derived xenograft models of NSCLC. Both the oximetry techniques have the potential to differentiate between normoxic and hypoxic regions of the tumor and reveal both baseline heterogeneity and differential response to therapeutic intervention. The response of the tumor models to therapeutic interventions indicates that, in conjunction with pO2, other factors such as tumor perfusion (essential for delivering HAPs) and relative expression of nitroreductases (essential for activating HAPs) may play an important role. The long term goal of the proposed research is the clinical translation of both the MRI techniques and aiding the design and development of personalized therapy (e.g. patient stratification for novel hypoxia activated pro-drugs) particularly for cancer.
ContributorsAgarwal, Shubhangi (Author) / Kodibagkar, Vikram D (Thesis advisor) / Inge, Landon J (Committee member) / Nikkhah, Mehdi (Committee member) / Pagel, Mark D. (Committee member) / Sadleir, Rosalind J (Committee member) / Arizona State University (Publisher)
Created2017
Description
Our cells need constant fuel and oxygen for the body to work properly and maintain cellular function. In high altitudes tissue oxygen levels fall and the body must work against this hypoxic challenge to maintain energetics and limit oxidative stress. Mammals living at high altitudes are challenged to sustain thermogenesis and aerobic exercise despite reduced amounts of available oxygen. Enhancements in oxidative capacity and oxygen diffusion capacity of skeletal muscle may be necessary to compensate for insufficient oxygen supply in tissues. Hypoxic conditions can cause a switch from aerobic metabolism to anaerobic metabolism. Due to previous research of Graham Scott and colleagues on “Adaptive Modifications of Muscle Phenotype in High-Altitude Deer Mice” and the SMack Lab at Arizona State University, the question of how low atmospheric oxygen levels affects the enzymatic activity in the gastrocnemius muscle of Gelada Monkeys compared to Rhesus Macaque Monkeys was researched. Lactate Dehydrogenase (LDH) activity was measured in the gastrocnemius tissue of 6 Gelada Monkeys (highland) and 6 Rhesus Macaque monkeys (lowland). LDH was expected to be greater in Gelada tissue samples due to heightened anaerobic metabolism in the presence of limited available oxygen in high altitude environments. Results showed higher LDH in Rhesus Macaque samples compared to Gelada samples, but this difference was not statistically significant. Despite nonsignificant data, this experiment is insightful into the effects of Hypoxic adaptation in skeletal muscle enzymatic activity in primates.
ContributorsSalehi, Yasmine (Author) / Snyder-Mackler, Noah (Thesis director) / Trumble, Ben (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution & Social Change (Contributor)
Created2023-05
Description
Magnetic resonance imaging (MRI) is a noninvasive imaging modality, which is used for many different applications. The versatility of MRI is in acquiring high resolution anatomical and functional images with no use of ionizing radiation. The contrast in MR images can be engineered by two different mechanisms with imaging parameters (TR, TE, α) and/or contrast agents. The contrast in the former is influenced by the intrinsic properties of the tissue (T1, T2, ρ), while the contrast agents change the relaxation rate of the protons to enhance contrast. Contrast agents have attracted a lot of attention because they can be modified with targeting groups to shed light on some physiological and biological questions, such as the presence of hypoxia in a tissue. Hypoxia, defined as lack of oxygen, has many known ramifications on the outcome of therapy in any condition. Hence its study is very important. The standard gold method to detect hypoxia, immunohistochemical (IHC) staining of pimonidazole, is invasive; however, there are many research groups focused on developing new and mainly noninvasive methods to investigate hypoxia in different tissues.Previously, a novel nitroimidazole-based T1 contrast agent, gadolinium tetraazacyclododecanetetraacetic acid monoamide conjugate of 2-nitroimidazole (GdDO3NI ), has been synthesized and characterized on subcutaneous prostate and lung tumor models. Here, its efficacy and performance on traumatic brain injuries and brain tumors are studied. The pharmacokinetic properties of the contrast agent the perfusion properties of brain tumors are investigated. These results can be used in personalized therapies for more effective results for patients.
Gadolinium (Gd), which is a strongly paramagnetic heavy metal, is routinely and widely used as an MR contrast agent by chelation with a biocompatible ligand which is typically cleared through the kidneys. While widely used, there are serious concerns for patients with impaired kidney function, as well as recent studies showed Gd accumulation in the bone and brain. Iron as a physiological ion is also capable of generating contrast in MR images. Here synthesis and characterization of an iron-based hypoxia targeting contrast agent is proposed to eliminate Gd-related complications and provide a cheaper and more economical alternative contrast agent to detect hypoxia.
ContributorsMoghadas, Babak (Author) / Kodibagkar, Vikram D (Thesis advisor) / Beeman, Scott (Committee member) / Muthuswamy, Jitendran (Committee member) / Nikkhah, Mehdi (Committee member) / Turner, Gregory (Committee member) / Arizona State University (Publisher)
Created2021
Description
Hypoxia-responses help coordinate the growth of oxygen-transporting tissues with the growth of other tissues during development. In Drosophila, hypoxia strongly affects development with flies being reared in a low oxygen environment showing smaller body sizes and diminished tracheal growth. The primary regulator of cellular hypoxic-responses is the hypoxia-inducible factor (HIF), and under normoxic conditions, HIF-alpha is hydroxylated by prolyl hydroxylase domain (PHD) on a proline residue inside the alpha leading to the proteins proteasome degradation downstream. However, in response to reduced oxygen, cells accumulate HIF- alpha, which then joins with the constituent HIF-beta in the cytosol, forming a HIF- alpha/beta heterodimer. Which, in turn, enters the nucleus and binds to hypoxic response elements, activating the hypoxic response genes. Hyperoxia has recently been shown to stimulates metabolic rates only at the last stage Drosophila's larval development (L3), indicating oxygen limitation occurs towards the end of development. Green fluorescent protein (GFP) was added to the oxygen-dependent domain of Drosophila HIF- Alpha (Sima) and a monomeric red fluorescent protein with a nuclear localization signal (mRFP-nls) was added to a protein under the same ubiquitin-69E promoter but is not affected by changing O2 levels. Using a Leica SP5 AOBS Spectral Confocal, third instar larvae were analyzed at the cellular level with attention focused on HIF- signaling in the central nervous system (CNS). L3 Drosophila were divided into groups of 0-12h, 12-24h, 24-48h, and 48-60h corresponding to their development. In each group, flies were either treated for 10-12 hours in 5% O2 or were left normoxic before fixation. What was overwhelmingly found is that HIF-signaling was most prominent during their early development (0-12h), with a significant decline as age increased (P=<0.001). There was also an observed hypoxic effect as animals treated in lower oxygen concentrations had significantly higher HIF signaling (P=<0.001). However, this effect still declines as larvae continued developing. This data supports the idea that internal hypoxia does not become severe during late third instar growth but may occur during the actual molt of the flies.
ContributorsWerkhoven, Simon (Author) / Harrison, Jon (Thesis director) / VandenBrooks, John (Committee member) / School of Molecular Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Cases of sudden unexpected infant deaths (SUID) have taken thousands of lives of infants from families each year. The dangers of accidental suffocation, sudden infant death syndrome (SIDs), and even unknown causes have been prevalent throughout history. There are several behavioral risk factors that are associated with SUIDS and SIDS, which threaten the life of infants less than one year of age because they are in their vulnerable state of being. Being cautious of the crib environment, sleeping position, and co-sleeping can all help in reducing the risk of developing SIDS. The goal of this project is to continue to spread awareness regarding preventable measures to protect infants from unintentional deaths. These risks are modifiable and can help reduce the decline of health and help first-time parent(s) and caregivers protect their young.
ContributorsChang, Jasmine (Author) / Dine, Hadaad (Co-author) / Hagler, Debra (Thesis director) / Sebbens, Danielle (Committee member) / Barrett, The Honors College (Contributor) / Edson College of Nursing and Health Innovation (Contributor)
Created2024-05