Medicine and Health Sciences Commons^™

Targeting The Tumor Core: Hypoxia-Responsive Nanoparticles For The Delivery Of Chemotherapy To Pancreatic Tumors, Matthew I. Confeld, Babak Mamnoon, Li Feng, Heather Jensen Smith, Priyanka Ray, James Froberg, Jiha Kim, Michael A. Hollingsworth, Mohiuddin Quadir, Yongki Choi, Sanku Mallik

Journal Articles: Eppley Institute

In pancreatic ductal adenocarcinoma (PDAC), early onset of hypoxia triggers remodeling of the extracellular matrix, epithelial-to-mesenchymal transition, increased cell survival, the formation of cancer stem cells, and drug resistance. Hypoxia in PDAC is also associated with the development of collagen-rich, fibrous extracellular stroma (desmoplasia), resulting in severely impaired drug penetration. To overcome these daunting challenges, we created polymer nanoparticles (polymersomes) that target and penetrate pancreatic tumors, reach the hypoxic niches, undergo rapid structural destabilization, and release the encapsulated drugs. In vitro studies indicated a high cellular uptake of the polymersomes and increased cytotoxicity of the drugs under hypoxia compared to …

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 …

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 …

Aminoglycosides Rapidly Inhibit Nad(P)H Metabolism Increasing Reactive Oxygen Species And Cochlear Cell Demise, Danielle E. Desa, Michael G. Nichols, Heather Jensen Smith

Journal Articles: Eppley Institute

Despite causing permanent hearing loss by damaging inner ear sensory cells, aminoglycosides (AGs) remain one of the most widely used classes of antibiotics in the world. Although the mechanisms of cochlear sensory cell damage are not fully known, reactive oxygen species (ROS) are clearly implicated. Mitochondrial-specific ROS formation was evaluated in acutely cultured murine cochlear explants exposed to gentamicin (GM), a representative ototoxic AG antibiotic. Superoxide (O2·-) and hydrogen peroxide (H2O2) were measured using MitoSOX Red and Dihydrorhodamine 123, respectively, in sensory and supporting cells. A 1-h GM exposure significantly increased O2·- formation in IHCs and increased H2O2 formation in …

Microscale Gene Expression Analysis Of Tumor-Associated Macrophages, Kuldeep S. Attri, Kamiya Mehla, Surendra K. Shukla, Pankaj K. Singh

Journal Articles: Eppley Institute

Macrophages, apart from being the key effector cells of the innate immune system, also play critical roles during the development and progression of various complex diseases, including cancer. Tumor-associated macrophages, infiltrate tumors during different stages of cancer progression to regulate motility, invasion, and intravasation to metastatic sites. Macrophages can exist in different polarization states associated with unique function in tumors. Since tumor-associated macrophages constitute a very small proportion of tumor cells, analysis of gene expression pattern using normal extraction buffer-based methods remains a challenging task. Therefore, it is imperative to develop low-throughput strategies to investigate transcriptional regulations from a small …

The Distinct Metabolic Phenotype Of Lung Squamous Cell Carcinoma Defines Selective Vulnerability To Glycolytic Inhibition, Justin Goodwin, Michael L. Neugent, Shin Yup Lee, Joshua H. Choe, Hyunsung Choi, Dana M. R. Jenkins, Robin J. Ruthenborg, Maddox W. Robinson, Ji Yun Jeong, Masaki Wake, Hajime Abe, Norihiko Takeda, Hiroko Endo, Masahiro Inoue, Zhenyu Xuan, Hyuntae Yoo, Min Chen, Jung-Mo Ahn, John D. Minna, Kristi L. Helke, Pankaj K. Singh, David B. Shackelford, Jung-Whan Kim

Journal Articles: Eppley Institute

Adenocarcinoma (ADC) and squamous cell carcinoma (SqCC) are the two predominant subtypes of non-small cell lung cancer (NSCLC) and are distinct in their histological, molecular and clinical presentation. However, metabolic signatures specific to individual NSCLC subtypes remain unknown. Here, we perform an integrative analysis of human NSCLC tumour samples, patient-derived xenografts, murine model of NSCLC, NSCLC cell lines and The Cancer Genome Atlas (TCGA) and reveal a markedly elevated expression of the GLUT1 glucose transporter in lung SqCC, which augments glucose uptake and glycolytic flux. We show that a critical reliance on glycolysis renders lung SqCC vulnerable to glycolytic inhibition, …

Silibinin-Mediated Metabolic Reprogramming Attenuates Pancreatic Cancer-Induced Cachexia And Tumor Growth., Surendra K. Shukla, Aneesha Dasgupta, Kamiya Mehla, Venugopal Gunda, Enza Vernucci, Joshua J. Souchek, Gennifer Goode, Ryan King, Anusha Mishra, Ibha Rai, Sangeetha Nagarajan, Nina V. Chaika, Fang Yu, Surendra K. Shukla

Journal Articles: Eppley Institute

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the US. Cancer-associated cachexia is present in up to 80% of PDAC patients and is associated with aggressive disease and poor prognosis. In the present studies we evaluated an anti-cancer natural product silibinin for its effectiveness in targeting pancreatic cancer aggressiveness and the cachectic properties of pancreatic cancer cells and tumors. Our results demonstrate that silibinin inhibits pancreatic cancer cell growth in a dose-dependent manner and reduces glycolytic activity of cancer cells. Our LC-MS/MS based metabolomics data demonstrates that silibinin treatment induces global metabolic reprogramming in pancreatic …

Gentamicin Differentially Alters Cellular Metabolism Of Cochlear Hair Cells As Revealed By Nad(P)H Fluorescence Lifetime Imaging, Lyandysha V. Zholudeva, Kristina G. Ward, Michael G. Nichols, Heather Jensen Smith

Journal Articles: Eppley Institute

Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). …

Nerve Growth Factor Regulates Neurolymphatic Remodeling During Corneal Inflammation And Resolution., Darci M. Fink, Alicia L. Connor, Philip M. Kelley, Maria M. Steele, Michael A. Hollingsworth, Richard M. Tempero

Journal Articles: Eppley Institute

The cellular and physiologic mechanisms that regulate the resolution of inflammation remain poorly defined despite their widespread importance in improving inflammatory disease outcomes. We studied the resolution of two cardinal signs of inflammation-pain and swelling-by investigating molecular mechanisms that regulate neural and lymphatic vessel remodeling during the resolution of corneal inflammation. A mouse model of corneal inflammation and wound recovery was developed to study this process in vivo. Administration of nerve growth factor (NGF) increased pain sensation and inhibited neural remodeling and lymphatic vessel regression processes during wound recovery. A complementary in vivo approach, the corneal micropocket assay, revealed that …

Intra-Tumoral Heterogeneity In Metastatic Potential And Survival Signaling Between Iso-Clonal Hct116 And Hct116b Human Colon Carcinoma Cell Lines., Sanjib Chowdhury, Melanie Ongchin, Elizabeth Sharratt, Ivan Dominguez, J. Wang, Michael G. Brattain, Ashwani Rajput

Journal Articles: Eppley Institute

BACKGROUND: Colorectal cancer (CRC) metastasis is a leading cause of cancer-related deaths in the United States. The molecular mechanisms underlying this complex, multi-step pathway are yet to be completely elucidated. Recent reports have stressed the importance of intra-tumoral heterogeneity in the development of a metastatic phenotype. The purpose of this study was to characterize the intra-tumoral phenotypic heterogeneity between two iso-clonal human colon cancer sublines HCT116 and HCT116b on their ability to undergo metastatic colonization and survive under growth factor deprivation stress (GFDS).

MATERIALS AND METHODS: HCT116 and HCT116b cells were transfected with green fluorescence protein and subcutaneously injected into …

Transforming Growth Factor-Β Suppresses Metastasis In A Subset Of Human Colon Carcinoma Cells., Neka A.K. Simms, Ashwani Rajput, Elizabeth A. Sharratt, Melanie Ongchin, Carol A. Teggart, J. Wang, Michael G. Brattain

Journal Articles: Eppley Institute

BACKGROUND: TGFβ signaling has typically been associated with suppression of tumor initiation while the role it plays in metastasis is generally associated with progression of malignancy. However, we present evidence here for an anti-metastatic role of TGFβ signaling.

METHODS: To test the importance of TGFβ signaling to cell survival and metastasis we compared human colon carcinoma cell lines that are either non-tumorigenic with TGFβ response (FET), or tumorigenic with TGFβ response (FETα) or tumorigenic with abrogated TGFβ response via introduction of dominant negative TGFβRII (FETα/DN) and their ability to metastasize. Metastatic competency was assessed by orthotopic transplantation. Metastatic colony formation …

Gentamicin Rapidly Inhibits Mitochondrial Metabolism In High-Frequency Cochlear Outer Hair Cells, Heather Jensen Smith, Richard Hallworth, Michael G. Nichols

Journal Articles: Eppley Institute

Aminoglycosides (AG), including gentamicin (GM), are the most frequently used antibiotics in the world and are proposed to cause irreversible cochlear damage and hearing loss (HL) in 1/4 of the patients receiving these life-saving drugs. Akin to the results of AG ototoxicity studies, high-frequency, basal turn outer hair cells (OHCs) preferentially succumb to multiple HL pathologies while inner hair cells (IHCs) are much more resilient. To determine if endogenous differences in IHC and OHC mitochondrial metabolism dictate differential sensitivities to AG-induced HL, IHC- and OHC-specific changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH) fluorescence during acute (1 h) GM treatment …

Renal Thrombotic Microangiopathy In Mice With Combined Deletion Of Endocytic Recycling Regulators Ehd3 And Ehd4., Manju George, Mark A. Rainey, Mayumi Naramura, Kirk W. Foster, Melissa S. Holzapfel, Laura L. Willoughby, Guoguang Ying, Rasna M. Goswami, Channabasavaiah B. Gurumurthy, Vimla Band, Simon C. Satchell, Hamid Band

Journal Articles: Eppley Institute

Eps15 Homology Domain-containing 3 (EHD3), a member of the EHD protein family that regulates endocytic recycling, is the first protein reported to be specifically expressed in the glomerular endothelium in the kidney; therefore we generated Ehd3(-/-) mice and assessed renal development and pathology. Ehd3(-/-) animals showed no overt defects, and exhibited no proteinuria or glomerular pathology. However, as the expression of EHD4, a related family member, was elevated in the glomerular endothelium of Ehd3(-/-) mice and suggested functional compensation, we generated and analyzed Ehd3(-/-); Ehd4(-/-) mice. These mice were smaller, possessed smaller and paler kidneys, were proteinuric and died between …

The Roles Of Conserved And Nonconserved Cysteinyl Residues In The Oligomerization And Function Of Mammalian Prestin, Benjamin Currall, Danielle Rossino, Heather Jensen Smith, Richard Hallworth

Journal Articles: Eppley Institute

The creation of several prestin knockout and knockin mouse lines has demonstrated the importance of the intrinsic outer hair cell membrane protein prestin to mammalian hearing. However, the structure of prestin remains largely unknown, with even its major features in dispute. Several studies have suggested that prestin forms homo-oligomers that may be stabilized by disulfide bonds. Our phylogenetic analysis of prestin sequences across chordate classes suggested that the cysteinyl residues could be divided into three groups, depending on the extent of their conservation between prestin orthologs and paralogs or homologs. An alanine scan functional analysis was performed of all nine …

Microrna-183 Family Expression In Hair Cell Development And Requirement Of Micrornas For Hair Cell Maintenance And Survival, Michael D. Weston, Marsha L. Pierce, Heather Jensen Smith, Bernd Fritzsch, Sonia Rocha-Sanchez, Kirk W. Beisel, Garrett A. Soukup

Journal Articles: Eppley Institute

MicroRNAs (miRNAs) post-transcriptionally repress complementary target gene expression and can contribute to cell differentiation. The coordinate expression of miRNA-183 family members (miR-183, miR-96, and miR-182) has been demonstrated in sensory cells of the mouse inner ear and other vertebrate sensory organs. To further examine hair cell miRNA expression in the mouse inner ear, we have analyzed miR-183 family expression in wild type animals and various mutants with defects in neurosensory development. miR-183 family member expression follows neurosensory cell specification, exhibits longitudinal (basal-apical) gradients in maturating cochlear hair cells, and is maintained in sensory neurons and most hair cells into adulthood. …

Nitrated Alpha-Synuclein Immunity Accelerates Degeneration Of Nigral Dopaminergic Neurons., Eric J. Benner, Rebecca Banerjee, Ashley D. Reynolds, Simon Sherman, Vladimir M. Pisarev, Vladislav Tsiperson, Craig Nemachek, Pawel Ciborowski, Serge Przedborski, R. Lee Mosley, Howard Gendelman

Journal Articles: Eppley Institute

BACKGROUND: The neuropathology of Parkinson's disease (PD) includes loss of dopaminergic neurons in the substantia nigra, nitrated alpha-synuclein (N-alpha-Syn) enriched intraneuronal inclusions or Lewy bodies and neuroinflammation. While the contribution of innate microglial inflammatory activities to disease are known, evidence for how adaptive immune mechanisms may affect the course of PD remains obscure. We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.

METHODS AND FINDINGS: Nitrotyrosine (NT)-modified alpha-Syn was detected readily in cervical lymph nodes (CLN) from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice. Antigen-presenting cells within the CLN …

Lateral Wall Protein Content Mediates Alterations In Cochlear Outer Hair Cell Mechanics Before And After Hearing Onset, Heather Jensen Smith, Richard Hallworth

Journal Articles: Eppley Institute

Specialized outer hair cells (OHCs) housed within the mammalian cochlea exhibit active, nonlinear, mechanical responses to auditory stimulation termed electromotility. The extraordinary frequency resolution capacity of the cochlea requires an exquisitely equilibrated mechanical system of sensory and supporting cells. OHC electromotile length change, stiffness, and force generation are responsible for a 100-fold increase in hearing sensitivity by augmenting vibrational input to non-motile sensory inner hair cells. Characterization of OHC mechanics is crucial for understanding and ultimately preventing permanent functional deficits due to overstimulation or as a consequence of various cochlear pathologies. The OHCs' major structural assembly is a highly-specialized lateral …

Long-Distance Three-Color Neuronal Tracing In Fixed Tissue Using Neurovue Dyes, Heather Jensen Smith, Brian Gray, Katharine Muirhead, Betsy Ohlsson-Wilhelm, Bernd Fritzsch

Journal Articles: Eppley Institute

Dissecting development of neuronal connections is critical for understanding neuronal function in both normal and diseased states. Charting the development of the multitude of connections is a monumental task, since a given neuron typically receives hundreds of convergent inputs from other neurons and provides divergent outputs for hundreds of other neurons. Although progress is being made utilizing various mutants and/or genetic constructs expressing fluorescent proteins like GFP, substantial work remains before a database documenting the development and final location of the neuronal pathways in an adult animal is completed. The vast majority of developing neurons cannot be specifically labeled with …

Requirement For The Betai And Betaiv Tubulin Isotypes In Mammalian Cilia., Heather C Jensen-Smith, Richard F Ludueña, Richard Hallworth

Journal Articles: Eppley Institute

Nielsen et al., [2001: Curr Biol 11:529-533], based on studies in Drosophila, have proposed that beta tubulin in axonemal microtubules must contain a specific acidic seven amino acid sequence in its carboxyl terminus. In mammals, the two betaIV isotypes (betaIVa and betaIVb) contain that sequence. In order to test the application of this hypothesis to mammals, we have examined the expression of beta tubulin isotypes in four different ciliated tissues (trachea, ependyma, uterine tube, and testis) using isotype-specific antibodies and indirect immunofluorescence. We find that betaIV tubulin is present in all ciliated cell types examined, but so is betaI tubulin. …

Cell Type-Specific Reduction Of Beta Tubulin Isotypes Synthesized In The Developing Gerbil Organ Of Corti, Heather Jensen Smith, Jonquille Eley, Peter S. Steyger, Richard F. Ludueña, Richard Hallworth

Journal Articles: Eppley Institute

There are seven isotypic forms of the microtubule protein beta tubulin in mammals, but not all isotypes are synthesized in every cell type. In the adult organ of Corti, each of the five major cell types synthesizes a different subset of isotypes. Inner hair cells synthesize only betaI and betaII tubulin, while outer hair cells make betaI and betaIV tubulin. Only betaII and betaIV tubulin are found in inner and outer pillar cells, while betaI, betaII, and betaIV tubulin are present in Deiters cells, and betaI, betaII and betaIII tubulin are found in organ of Corti dendrites. During post-natal organ …

Selective Expression Of Beta Tubulin Isotypes In Gerbil Vestibular Sensory Epithelia And Neurons, Brian Perry, Heather Jensen Smith, Richard F. Ludueña, Richard Hallworth

Journal Articles: Eppley Institute

The seven mammalian isotypes of beta tubulin are strikingly similar in amino acid sequence. The differences in isotypic sequence, although small, are nonetheless conserved in evolution, which suggests that they may confer distinct functional roles. If so, such roles should be reflected in the selective expression of isotypes by cell type, or even in the sorting of isotypes to within-cell pools. Hair cells of the vestibular sensory epithelia each possess a kinocilium, a microtubule-based organelle that could represent a distinct microtubule compartment, separate from the extensive microtubule network in the soma. The afferent neurons that innervate the vestibular sensory epithelia …

Differential Synthesis Of Beta-Tubulin Isotypes In Gerbil Nasal Epithelia, Karen Woo, Heather Jensen Smith, Richard F. Ludueña, Richard Hallworth

Journal Articles: Eppley Institute

Compartmentalization of beta-tubulin isotypes within cells according to function was examined in gerbil olfactory and respiratory epithelia by using specific antibodies to four beta-tubulin isotypes (beta(I), beta(II), beta(III), and beta(IV)). Isotype synthesis was cell-type-specific, but the localization of the isotypes was not compartmentalized. All four isotypes were found in the cilia, dendrites, somata, and axons of olfactory neurons. Only two isotypes (beta(I) and beta(IV)) were present in the cilia of nasal respiratory epithelial cells. The beta(IV) isotype, thought to be an essential component of cilia, was present in olfactory neurons and respiratory epithelial cells, which are ciliated, but was not …