Medicine and Health Sciences Commons^™

The Role Of Histone Chaperone Fact Complex In Base Excision Repair Pathway And Its Therapeutic Potential In Colon Cancer And Medulloblastoma, Heyu Song

Theses & Dissertations

Base excision repair (BER) pathway is required for the removal of damaged bases caused by alkylation, oxidation and ring-saturation. Human apurinic/apyrimidinic endonuclease 1 (APE1) plays a central role in BER pathway. Although repair of damaged bases by recombinant APE1 has been well investigated in vitro, how APE1 gains access to damaged bases in the context of chromatin is largely unknown. A prominent member of the histone chaperone family, FACT (Facilitates Chromatin Transcription) is thought to reorganize nucleosomes through the destabilization of multiple intra-nucleosome contacts. FACT complex is composed of two polypeptides identified as SPT16 (Suppressor of Ty 16) and SSRP1 …

Targeted Inhibition Of Histone Deacetyltransferases For Pancreatic Cancer Therapy, Richard Laschanzky

Theses & Dissertations

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with a dismal five-year survival rate of less than 10%. One major obstacle in PDAC treatment is acquired drug resistance. Pan-histone deacetylase inhibitors (pan-HDACi) are a relatively new class of anti-cancer drugs, with demonstrated ability to overcome drug resistance and re-sensitize PDAC tumors to Gemcitabine (Gem). These agents target HDACs, a family of 18 enzymes (divided into four classes, I-IV) that catalyze the deacetylation of histones and other cellular proteins and have multiple effects on cell growth, differentiation, survival, and tumorigenesis. Although pan-HDACi have shown significant efficacy in preclinical analysis, and some …

Association Between Gastroduodenal Ulcer And Age Of Diagnosis Of Head And Neck, Gastroduodenal And Pancreatic Cancer, Rukevwe Madusor

Capstone Experience

Background: Cancer is the second leading cause of death in the United States and remains a major public health problem worldwide. Epidemiological studies have demonstrated that insulin like growth factor-1 (IGF-1) is linked to ulcers and most cancers. Although studies have investigated the role of IGF1 in ulcer healing and cancer pathogenesis, the link between ulcer and cancer remains unclear. Hence, we assessed the relationship between ulcers and cancers.

Methods: This study consists of a sample of 180 cancer patients obtain by convenience sampling who were seen at Nebraska Medicine and were enrolled in the integrated cancer repository for cancer …

Role Of Rac1-Pak Pathway In Aggressive B-Cell Lymphoma, Tian Tian

Theses & Dissertations

Aggressive B-cell lymphomas are diverse group of neoplasms that arise at different stages of B-cell development and by various mechanisms of neoplastic transformation. Aggressive B-cell lymphomas include many types, subtypes and variants of diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), mantle cell lymphoma (MCL) and B lymphoblastic lymphoma. The treatment of patients with aggressive B-cell lymphomas remains a clinical challenge. Conventional chemotherapeutic regimens, mainly based on the CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone) combination, obtain a relatively high number of complete or partial clinical responses (20-80%), but the tumor relapses in most patients, who will die of the disease. …

The Mitochondrial Deoxyguanosine Kinase Is Required For Cancer Cell Stemness In Lung Adenocarcinoma, Shengchen Lin, Chongbiao Huang, Jianwei Sun, Oana Bollt, Xiuchao Wang, Eric Martine, Jiaxin Kang, Matthew D. Taylor, Bin Fang, Pankaj K. Singh, John Koomen, Jihui Hao, Shengyu Yang

Journal Articles: Eppley Institute

The mitochondrial deoxynucleotide triphosphate (dNTP) is maintained by the mitochondrial deoxynucleoside salvage pathway and dedicated for the mtDNA homeostasis, and the mitochondrial deoxyguanosine kinase (DGUOK) is a rate-limiting enzyme in this pathway. Here, we investigated the role of the DGUOK in the self-renewal of lung cancer stem-like cells (CSC). Our data support that DGUOK overexpression strongly correlates with cancer progression and patient survival. The depletion of DGUOK robustly inhibited lung adenocarcinoma tumor growth, metastasis, and CSC self-renewal. Mechanistically, DGUOK is required for the biogenesis of respiratory complex I and mitochondrial OXPHOS, which in turn regulates CSC self-renewal through AMPK-YAP1 signaling. …

Mitochondrial Superoxide Disrupts The Metabolic And Epigenetic Landscape Of Cd4, Cassandra M. Moshfegh, Christopher W. Collins, Venugopal Gunda, A. Vasanthakumar, J. Z. Cao, Pankaj K. Singh, L. A. Godley, Adam J. Case

Journal Articles: Eppley Institute

While the role of mitochondrial metabolism in controlling T-lymphocyte activation and function is becoming more clear, the specifics of how mitochondrial redox signaling contributes to T-lymphocyte regulation remains elusive. Here, we examined the global effects of elevated mitochondrial superoxide (O₂^-) on T-lymphocyte activation using a novel model of inducible manganese superoxide dismutase (MnSOD) knock-out. Loss of MnSOD led to specific increases in mitochondrial O₂^- with no evident changes in hydrogen peroxide (H₂O₂), peroxynitrite (ONOO^-), or copper/zinc superoxide dismutase (CuZnSOD) levels. Unexpectedly, both mitochondrial and glycolytic metabolism showed significant reductions …

Selective Inhibition Of Histone Deacetylases 1/2/6 In Combination With Gemcitabine: A Promising Combination For Pancreatic Cancer Therapy, Richard S. Laschanzky, Lisa E. Humphrey, Jihyun Ma, Lynette M. Smith, Thomas J. Enke, Surendra K. Shukla, Aneesha Dasgupta, Pankaj K. Singh, Gillian M. Howell, Michael G. Brattain, Quan P. Ly, Adrian R. Black, Jennifer D. Black

Journal Articles: Eppley Institute

Pancreatic ductal adenocarcinoma (PDAC) has a five-year survival rate of <10% due in part to a lack of effective therapies. Pan-histone deacetylase (HDAC) inhibitors have shown preclinical efficacy against PDAC but have failed in the clinic due to toxicity. Selective HDAC inhibitors may reduce toxicity while retaining therapeutic efficacy. However, their use requires identification of the specific HDACs that mediate the therapeutic effects of HDAC inhibitors in PDAC. We determined that the HDAC1/2/3 inhibitor Mocetinostat synergizes with the HDAC4/5/6 inhibitor LMK-235 in a panel of PDAC cell lines. Furthermore, while neither drug alone synergizes with gemcitabine, the combination of Mocetinostat, LMK-235, and gemcitabine showed strong synergy. Using small interfering (si)RNA-mediated knockdown, this synergy was attributed to inhibition of HDACs 1, 2, and 6. Pharmacological inhibition of HDACs 1 and 2 with Romidepsin and HDAC6 with ACY-1215 also potently synergized with gemcitabine in a panel of PDAC cell lines, and this drug combination potentiated the antitumor effects of gemcitabine against PDAC xenografts in vivo. Collectively, our data show that inhibition of multiple HDACs is required for therapeutic effects of HDAC inhibitors and support the development of novel strategies to inhibit HDACs 1, 2, and 6 for PDAC therapy.

Fascin Controls Metastatic Colonization And Mitochondrial Oxidative Phosphorylation By Remodeling Mitochondrial Actin Filaments, Shengchen Lin, Chongbiao Huang, Venugopal Gunda, Jianwei Sun, Srikumar P. Chellappan, Zengxun Li, Victoria Izumi, Bin Fang, John Koomen, Pankaj K. Singh, Jihui Hao, Shengyu Yang

Journal Articles: Eppley Institute

The deregulation of the actin cytoskeleton has been extensively studied in metastatic dissemination. However, the post-dissemination role of the actin cytoskeleton dysregulation is poorly understood. Here, we report that fascin, an actin-bundling protein, promotes lung cancer metastatic colonization by augmenting metabolic stress resistance and mitochondrial oxidative phosphorylation (OXPHOS). Fascin is directly recruited to mitochondria under metabolic stress to stabilize mitochondrial actin filaments (mtF-actin). Using unbiased metabolomics and proteomics approaches, we discovered that fascin-mediated mtF-actin remodeling promotes mitochondrial OXPHOS by increasing the biogenesis of respiratory Complex I. Mechanistically, fascin and mtF-actin control the homeostasis of mtDNA to promote mitochondrial OXPHOS. The …

Human Islet Response To Selected Type 1 Diabetes-Associated Bacteria: A Transcriptome-Based Study, Ahmed M. Abdellatif, Heather Jensen Smith, Robert Z. Harms, Nora Sarvetnick

Journal Articles: Eppley Institute

Type 1 diabetes (T1D) is a chronic autoimmune disease that results from destruction of pancreatic β-cells. T1D subjects were recently shown to harbor distinct intestinal microbiome profiles. Based on these findings, the role of gut bacteria in T1D is being intensively investigated. The mechanism connecting intestinal microbial homeostasis with the development of T1D is unknown. Specific gut bacteria such as Bacteroides dorei (BD) and Ruminococcus gnavus (RG) show markedly increased abundance prior to the development of autoimmunity. One hypothesis is that these bacteria might traverse the damaged gut barrier, and their constituents elicit a response from human islets that causes …

Metabolic Alterations In Pancreatic Cancer Progression, Enza Vernucci, Jaime Abrego, Venugopal Gunda, Surendra K. Shukla, Aneesha Dasgupta, Vikrant Rai, Nina V. Chaika, Kyla Buettner, Alysha Illies, Fang Yu, Audrey J. Lazenby, Benjamin J. Swanson, Pankaj K. Singh

Journal Articles: Eppley Institute

Pancreatic cancer is the third leading cause of cancer-related deaths in the USA. Pancreatic tumors are characterized by enhanced glycolytic metabolism promoted by a hypoxic tumor microenvironment and a resultant acidic milieu. The metabolic reprogramming allows cancer cells to survive hostile microenvironments. Through the analysis of the principal metabolic pathways, we identified the specific metabolites that are altered during pancreatic cancer progression in the spontaneous progression (KPC) mouse model. Genetically engineered mice exhibited metabolic alterations during PanINs formation, even before the tumor development. To account for other cells in the tumor microenvironment and to focus on metabolic adaptations concerning tumorigenic …

Inhibition Of Geranylgeranyl Diphosphate Synthase Is A Novel Therapeutic Strategy For Pancreatic Ductal Adenocarcinoma, Staci L. Haney, Michelle L. Varney, Yashpal S. Chhonker, Simon Shin, Kamiya Mehla, Ayrianne J. Crawford, Heather Jensen Smith, Lynette M. Smith, Daryl J. Murry, Michael A. Hollingsworth, Sarah A. Holstein

Journal Articles: Eppley Institute

Rab proteins play an essential role in regulating intracellular membrane trafficking processes. Rab activity is dependent upon geranylgeranylation, a post-translational modification that involves the addition of 20-carbon isoprenoid chains via the enzyme geranylgeranyl transferase (GGTase) II. We have focused on the development of inhibitors against geranylgeranyl diphosphate synthase (GGDPS), which generates the isoprenoid donor (GGPP), as anti-Rab agents. Pancreatic ductal adenocarcinoma (PDAC) is characterized by abnormal mucin production and these mucins play important roles in tumor development, metastasis and chemo-resistance. We hypothesized that GGDPS inhibitor (GGDPSi) treatment would induce PDAC cell death by disrupting mucin trafficking, thereby inducing the unfolded …