Medicine and Health Sciences Commons^™

Exosomes Secreted Under Hypoxia Enhance Stemness In Ewing’S Sarcoma And Transform Microenvironment Cells, Matthew J. Kling

Theses & Dissertations

Intercellular communication between tumor cells and stroma within the hypoxic microenvironment promote aggressiveness and poor patient prognoses in ways that remain unclear. Here we show that hypoxic Ewing’s sarcoma (EWS) cells release exosomes that promote sphere formation, a stem-like phenotype, in EWS cells by enhancing survival and a cancer-associated phenotype in fibroblasts (CAFs). Given that hypoxia enriches for stem-like cells, we exposed EWS cells to hypoxia and hypoxic EWS-derived exosomes and assessed the stem cell phenotype. Hypoxia and hypoxic EWS-derived exosomewere found to enhance TIC formation in vitro and in vivo by reprogramming EWS cells. Analysis of the hypoxic exosomal …

Metabolic Regulation Of Cellular Signaling, Rashid John Darbandi

Theses and Dissertations (ETD)

Using the biochemically tractable Xenopus oocyte model system, we have previously characterized a novel metabolic regulation of cell death. We found that glucose-6-phosphate (G6P) via the pentose phosphate pathway leads to increased nicotinamide adenine dinucleotide phosphate (NADPH) levels, a subsequent increase in cytosolic acetyl-coenzyme A and activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII). We recently identified coenzyme A (CoA), derived from the breakdown of acetyl-CoA, as the key metabolic signal that mediates a novel mechanism of calmodulindependent activation of CaMKII. CoA binds directly to the calmodulin (CaM) binding domain (CaMBD) of CaMKII resulting in its activation and downstream inhibitory phosphorylation …

Priming Cardiovascular Stem Cells For Transplantation Using Short-Term Hypoxia, Ivan Hernandez

Electronic Theses, Projects, and Dissertations

Conventional medical treatments fail to address the underlying problems associated with the damage inflicted by a coronary event. Thus, the long-term prognosis of patients admitted for heart failure is disheartening, with reported survival rates of 25 percent. Recent advances in stem cell research highlight the potential benefits of autologous stem cell transplantation for stimulating repair in heart tissue. However, a majority of those suffering from cardiovascular diseases are older adults whose autologous cells no longer possess optimum functional capacity. Additional work is needed to identify the optimal cell types or conditions that will promote cardiovascular regeneration across all age groups. …

The Role Of Amp-Activated Protein Kinase (Ampk) In Tumorigenesis, Fei Han

Dissertations & Theses (Open Access)

AMPK plays a central role in controlling cellular and whole body energy level. Increasing studies have also discovered the diverse function of AMPK in cancer, such as autophagy and mitochondria biogenesis. However, how AMPK promotes cancer progression is still not clear. Here, we show that AMPK is essential for EGF-induced Akt activation, Glut1 expression, and glucose uptake. AMPK is also required for various stresses induced Akt activation and promote cell survival, including hypoxia and glucose deprivation. In addition, we found glucose deprivation-induced VEGF expression and secretion is also depend on AMPK, which may contribute to angiogenesis of surrounding endothelial cell …

Structural Basis For Lipid-And Calmodulin-Mediated Akt Activation In Breast Cancer Cells, Constance Agamasu

All ETDs from UAB

Growth and survival signals initiated at the cell surface by receptor-ligand interactions often involve a downstream activation of Akt, a serine/threonine kinase critical in regulating cell survival, apoptosis and oncogenesis. Hyper-activation of Akt is a common tumorigenic event, thereby making the Akt activation pathway a prime target for cancer therapy. The translocation of Akt to the plasma membrane (PM) for phosphorylation is a critical step in the Akt activation pathway. It has been established that membrane binding of Akt is mediated by direct interactions between its pleckstrin homology domain (PHD) and membrane lipid phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3]. There is now emerging …

Systemic Insulin Sensitivity And Skeletal Muscle Akt Signaling In Rats Artificially Selected For Low And High Aerobic Capacity, Kyle Levi Fulghum

MSU Graduate Theses

The mechanism(s) linking physical inactivity, obesity, and type-II diabetes are unclear. I hypothesized low intrinsic aerobic capacity is associated with reduced systemic insulin sensitivity via skeletal muscle insulin signaling. After 34 generations of selective breeding, high aerobic capacity (HCR) rats exhibited an 8-fold increase in running distance vs low aerobic capacity (LCR) rats (n=14 per group). LCR rats had higher rates of weight gain vs HCR (p<0.05) though food consumption was constant (p=0.86) over a 12-week study. Rats were divided into 4 groups: 1) LCR-Sham Surgery, 2) LCR-Catheterization, 3) HCR-Sham Surgery or 4) HCR-Catheterization (n=7 per group). Euglycemic-hyperinsulinemic clamps on catheterized rats tested insulin sensitivity while sham LCR and HCR were used for basal tissue analysis. Plasma insulin levels did not differ during the clamps, but LCR required lower glucose infusion rates than HCR (p<0.05). Upon insulin stimulation, both absolute and normalized phospho-Akt(Ser473) of soleus muscle were significantly increased in HCR above basal group (p<0.05), but not in LCR. No difference was observed between insulin-stimulated phospho-Akt(Ser473) of HCR and LCR groups . These data support that LCR is linked to a reduction in insulin sensitivity in vivo without impairments of insulin-stimulated skeletal muscle phospho-Akt(Ser473) vs HCR rats.

The Role Of Traf6 Phosphorylation In Src/Traf6-Mediated Ikk, Jnk, Akt Activation And Tumorigenesis, Yun Seong Jeong

Dissertations & Theses (Open Access)

TRAF6 E3 ligase regulates numerous essential biological processes such as innate immune response, cell survival and osteoclast differentiation. Upon activation, it mediates activation of IKK/NF-κB and JNK signaling in response to engagement of toll-like receptor 4 (TLR4), interleukin-1 receptor (IL-1R), and receptor activator of NF-κB (RANK) to their cognate ligands, including lipopolysaccharide (LPS), IL-1, and RANK ligand (RANKL). Recently, TRAF6 has also been shown to be involved in Akt signaling activation upon activation of insulin-like growth factor-1 receptor (IGF-1R), in turn orchestrating cell survival and tumorigenesis. Therefore, TRAF6 is a key player for the activation of IKK, JNK and Akt …

Regulation Of Glucose Homeostasis By The Phlpp1 Phosphatase, Kara L. Larson

Theses and Dissertations--Molecular and Cellular Biochemistry

Type 2 diabetes mellitus is a metabolic disease that affects one in ten people in the United States. It is caused by a combination of genetics and lifestyle factors. Disease progression begins with insulin resistance in peripheral tissues followed by pancreatic beta-cell failure. The mechanisms behind disease progression are not completely understood. PH domain leucine rich repeat protein phosphatase 1 (PHLPP1) is a known regulator of Akt and other members of the AGC kinase family. Akt has been established to play a role in numerous metabolic signaling pathways, including insulin action. It is hypothesized that as a regulator of Akt, …

The Regulation Of Mtorc2 Kinase Activity And Complex Integrity, Chien-Hung Chen

Dissertations & Theses (Open Access)

Growth factor signaling promotes anabolic processes via activation of the

PI3K-Akt kinase cascade. Deregulation of the growth factor-dependent PI3K-Akt

pathway was implicated in tumorigenesis. Akt is an essential serine/threonine

protein kinase that controls multiple physiological functions such as cell growth,

proliferation, and survival to maintain cellular homeostasis. Recently, the

mammalian Target of Rapamycin Complex 2 (mTORC2) was identified as the

main Akt Ser-473 kinase, and Ser-473 phosphorylation is required for Akt

hyperactivation. However, the detailed mechanism of mTORC2 regulation in

response to growth factor stimulation or cellular stresses is not well understood.

In the first project, we studied the regulation …

Development Of Dual-Pathway Inhibitors Of Raf/Mek/Erk And Pi3k/Akt Signaling Pathways., Sasha Fraser

Theses and Dissertations

In the present study, we designed a new chemical template that contains an oxindole moiety as potential dual-pathway inhibitors of the Raf/MEK/ERK and PI3K/Akt signaling pathways. The design hypothesis is to evaluate whether the oxindole ring system will approximately orient functional groups in a similar manner to the thiazolidinedione moiety, and thus maintain biological activity as dual-pathway inhibitors of the Raf/MEK/ERK and PI3K/Akt signaling pathways. Furthermore, the oxindole ring will provide the flexibility to allow the introduction of various substituents on the oxindole moiety, thereby facilitating comprehensive SAR studies to further explore the biological activity.

The Role Of Receptor Tyrosine Kinase Axl In Pancreatic Ductal Adenocarcinoma And Its Regulation By Hematopoietic Progenitor Kinase 1, Xianzhou Song

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies with less than 5% of five year survival rate. New molecular markers and new therapeutic targets are urgently needed for patients with PDA. Oncogenic receptor tyrosine kinase Axl has been reported to be overexpressed in many types of human malignancies, including diffuse glioma, melanoma, osteosarcoma, and carcinomas of lung, colon, prostate, breast, ovary, esophagus, stomach, and kidney. However, the expression and functions of Axl in PDA are unclear. We hypothesized that Axl contributes to the development and progression of PDA. We examined Axl expression in 54 human PDA samples …

The Effect Of Betaine Supplementation On Performance And Muscle Mechanisms, Jenna M. Apicella

Master's Theses

Background: Recent research has shown that betaine supplementation can increase strength and power performance. To further investigate the ergogenic effects of betaine supplementation a balanced, randomized, double-blind, repeated measures crossover study was designed to examine select hormonal and muscle signaling responses during supplementation.

Methods: Twelve recreationally active men (age, 19.7 ± 1.23 years; height, 172.6 ± 5.61 cm; weight, 84.27 ± 15.3 kg; body fat, 18.7 ± 7.0%; BMI, 28.2 ± 4.0) with a minimum of 3 months of resistance training including back squat and bench press participated in the study. A within crossover design was utilized and subjects were …

Molecular Mechanism Of Agc Kinases In Human Malignant, Shaokun Shu

USF Tampa Graduate Theses and Dissertations

The maintenance of normal cell function and tissue homeostasis is dependent on the precise regulation of multiple signaling pathways that control cellular decisions to either proliferate, differentiate, arrest cell growth, or initiate programmed cell death (apoptosis). Cancer arises when clones of mutated cells escape this balance and proliferate inappropriately without compensatory apoptosis. Deregulated cell growth occurs as a result of perturbed signal transduction that modulates or alters cellular behavior or function to keep the critical balance between the rate of cell-cycle progression (cell division) and cell growth (cell mass) on one hand, and programmed cell death (apoptosis, autophagy) on the …

Notch-1 Activates Nf-Кb Activity In Cervical Cancer And Estrogen Receptor Negative Breast Cancer, Yin Peng

Dissertations

Breast and cervical cancer are two common cancers that severely endanger women's health. The fatality rates of breast and cervical cancer are ranked first and fifth, respectively, in cancer related deaths in women worldwide. Continuous dedication to cancer research is urgently required to elucidate the cancer cell survival mechanism that is responsible for disease aggressiveness and poor prognosis.

Emerging data indicate that Notch-1 is aberrantly regulated in human cervical and ER- breast cancer and inhibiting Notch-1 sensitizes cancer cells to apoptosis. However, the mechanism by which Notch-1 promotes cell survival is not known. NF-КB is also deregulated in these two …

Regulation Of Glycogen Synthase Kinase 3 In The Pathophysiology And Treatment Of Mood Disorders, Abigail Marie Polter

All ETDs from UAB

Mood disorders are devastating psychiatric illnesses that will affect as many as one in every five persons worldwide over the course of their lifetime. Significant gaps still remain in our understanding of these illnesses and outcomes for many patients are far from optimal. Glycogen Synthase Kinase 3 (GSK3) is a protein kinase that is increasingly recognized as playing an important role in a number of neuronal functions, as well as in pathological states such as mood disorders. GSK3 is inhibited in the brain by phosphorylation on an N-terminal serine. Several treatments for mood disorders, including lithium, antidepressants, and atypical antipsychotics …

Translocation And Function Of Akt In The Mitochondria, Keri A. Mans

All ETDs from UAB

The ubiquitously expressed kinase Akt is a known survival protein, and is involved in multiple cell signaling cascades, notably the phosphatidylinositol 3-kinase (PI3K) pathway. Active Akt translocates from the plasma membrane to different subcellular compartments, including mitochondria, where it phosphorylates compartment-specific substrates. The mechanism of this translocation and the specific function of Akt within the mitochondria remains a mystery. The goals of this study were to elucidate the mechanism by which Akt enters the mitochondria and examine the role of Akt in mitochondrial function. Finally, the possibilities of using post-mortem human brain tissue to study mitochondrial function in normal and …

Lean And Obese Zucker Rats Exhibit Different Patterns Of P70s6kinase Regulation In The Tibialis Anterior Muscle In Response To High Force Muscle Contraction, Anjaiah Katta

Theses, Dissertations and Capstones

Increased muscle loading results in phosphorylation of the 70 kDa ribosomal S6 kinase (p70s6k) signaling pathway and this event strongly correlates with degree of muscle adaptation following resistance exercise. Here, we compared the basal and contraction- induced phosphorylation of p70s6k, Akt and mTOR in tibialis anterior muscles of lean and obese Zucker rats. Immunoblotting demonstrated differences in level of basal p70S6k phosphorylation (Thr 389) in the normal and diabetic TA. HFES had an increase in p70S6k (Thr389) phosphorylation at 0-, 1- and 3-hr in lean TA and only at 3-hr in obese TA. mTOR (Ser 2448) Phosphorylation was elevated in …