Life Sciences Commons^™

Analysis Of Rna Expression Of Normal And Cancer Tissues Reveals High Correlation Of Cop9 Gene Expression With Respiratory Chain Complex Components, Christina A. Wicker, Tadahide Izumi

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: The COP9 signalosome, composed of eight subunits, is implicated in cancer genetics with its deneddylase activity to modulate cellular concentration of oncogenic proteins such as IkB and TGFβ. However, its function in the normal cell physiology remains elusive. Primarily focusing on gene expression data of the normal tissues of the head and neck, the cancer genome atlas (TCGA) database was used to identify groups of genes that were expressed synergistically with the COP9 genes, particularly with the COPS5 (CSN5), which possesses the catalytic activity of COP9.

RESULTS: Expressions of seven of the COP9 genes (COPS2, COPS3, COPS4, COPS5, COPS6, …

Pleckstrin Homology (Ph) Domain Leucine-Rich Repeat Protein Phosphatase Controls Cell Polarity By Negatively Regulating The Activity Of Atypical Protein Kinase C, Xiaopeng Xiong, Xin Li, Yang-An Wen, Tianyan Gao

Markey Cancer Center Faculty Publications

The proper establishment of epithelial polarity allows cells to sense and respond to signals that arise from the microenvironment in a spatiotemporally controlled manner. Atypical PKCs (aPKCs) are implicated as key regulators of epithelial polarity. However, the molecular mechanism underlying the negative regulation of aPKCs remains largely unknown. In this study, we demonstrated that PH domain leucine-rich repeat protein phosphatase (PHLPP), a novel family of Ser/Thr protein phosphatases, plays an important role in regulating epithelial polarity by controlling the phosphorylation of both aPKC isoforms. Altered expression of PHLPP1 or PHLPP2 disrupted polarization of Caco2 cells grown in 3D cell cultures …

Hexavalent Chromium Induces Malignant Transformation Of Human Lung Bronchial Epithelial Cells Via Ros-Dependent Activation Of Mir-21-Pdcd4 Signaling, Poyil Pratheeshkumar, Young-Ok Son, Sasidharan Padmaja Divya, Lilia Turcios, Ram Vinod Roy, John Andrew Hitron, Lei Wang, Donghern Kim, Jin Dai, Padmaja Asha, Zhuo Zhang, Xianglin Shi

Center for Research on Environmental Disease Faculty Publications

Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with an increased risk of lung cancer. However, the mechanisms underlying Cr(VI)-induced carcinogenesis remain unclear. MicroRNA-21 (miR-21) is a key regulator of oncogenic processes. Studies have shown that miR-21 exerts its oncogenic activity by targeting the tumor suppressor gene programmed cell death 4 (PDCD4). The present study examined the role of miR-21-PDCD4 signaling in Cr(VI)-induced cell transformation and tumorigenesis. Results showed that Cr(VI) induces ROS generation in human bronchial epithelial (BEAS-2B) cells. Chronic exposure to Cr(VI) is able to cause malignant transformation in BEAS-2B cells. Cr(VI) caused a significant increase of …

Klf4 Deletion Alters Gastric Cell Lineage And Induces Muc2 Expression, Tianxin Yu, Xi Chen, T. Lin, J. Liu, M. Li, W. Zhang, X. Xu, W. Zhao, M. Liu, Dana L. Napier, Chi Wang, B. Mark Evers, Chunming Liu

Markey Cancer Center Faculty Publications

Gastric cancer is one of the most common types of cancer in the world, particularly in underdeveloped countries. The mechanism of gastric cancer is less understood compared with other types of gastrointestinal (GI) cancers. Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor and is a potential tumor suppressor in GI cancers. In this study, we have generated two mouse models, Rosa-Cre;Klf4^fl/fl and Lgr5-Cre;Klf4^fl/fl. KLF4 was deleted by Rosa-Cre in the gastric epithelia cells or by Lgr5-Cre in the antral stem cells in the adult mice. KLF4 deletion resulted in increased proliferating cells and decreased pit mucous …

Melanocortin 1 Receptor: Structure, Function, And Regulation, Erin M. Wolf Horrell, Mary C. Boulanger, John A. D'Orazio

Physiology Faculty Publications

The melanocortin 1 receptor (MC1R) is a melanocytic G_s protein coupled receptor that regulates skin pigmentation, UV responses, and melanoma risk. It is a highly polymorphic gene, and loss of function correlates with a fair, UV-sensitive, and melanoma-prone phenotype due to defective epidermal melanization and sub-optimal DNA repair. MC1R signaling, achieved through adenylyl cyclase activation and generation of the second messenger cAMP, is hormonally controlled by the positive agonist melanocortin, the negative agonist agouti signaling protein, and the neutral antagonist β-defensin 3. Activation of cAMP signaling up-regulates melanin production and deposition in the epidermis which functions to limit UV …

S100a4 Drives Non-Small Cell Lung Cancer Invasion, Associates With Poor Prognosis, And Is Effectively Targeted By The Fda-Approved Anti-Helminthic Agent Niclosamide, Rachel L. Stewart, Brittany L. Carpenter, Dava S. West, Teresa Knifley, Lili Liu, Chi Wang, Heidi L. Weiss, Tamas S. Gal, Eric B. Durbin, Susanne M. Arnold, Kathleen L. O'Connor, Min Chen

Markey Cancer Center Faculty Publications

S100A4 (metastasin-1), a metastasis-associated protein and marker of the epithelial to mesenchymal transition, contributes to several hallmarks of cancer and has been implicated in the progression of several types of cancer. However, the impacts of S100A4 signaling in lung cancer progression and its potential use as a target for therapy in lung cancer have not been properly explored. Using established lung cancer cell lines, we demonstrate that S100A4 knockdown reduces cell proliferation, invasion and three-dimensional invasive growth, while overexpression of S100A4 increases invasive potential. In patient-derived tissues, S100A4 is preferentially elevated in lung adenocarcinoma. This elevation is associated with lymphovascular …

P-Rex1 Promotes Resistance To Vegf/Vegfr-Targeted Therapy In Prostate Cancer, Hira Lal Goel, Bryan Pursell, Leonard D. Shultz, Dale L. Greiner, Rolf A Brekken, Craig W. Vander Kooi, Arthur M. Mercurio

Molecular and Cellular Biochemistry Faculty Publications

Autocrine VEGF signaling is critical for sustaining prostate and other cancer stem cells (CSCs), and it is a potential therapeutic target, but we observed that CSCs isolated from prostate tumors are resistant to anti-VEGF (bevacizumab) and anti-VEGFR (sunitinib) therapy. Intriguingly, resistance is mediated by VEGF/neuropilin signaling, which is not inhibited by bevacizumab and sunitinib, and it involves the induction of P-Rex1, a Rac GEF, and consequent Rac1-mediated ERK activation. This induction of P-Rex1 is dependent on Myc. CSCs isolated from the PTEN^pc−/− transgenic model of prostate cancer exhibit Rac1-dependent resistance to bevacizumab. Rac1 inhibition or P-Rex1 downregulation increases the …

Autocrine Epiregulin Activates Egfr Pathway For Lung Metastasis Via Emt In Salivary Adenoid Cystic Carcinoma, Shuli Liu, Dongxia Ye, Dongliang Xu, Yueling Liao, Ling Zhang, Liu Liu, Wenwen Yu, Yanan Wang, Yue He, Jingzhou Hu, Wenzheng Guo, Tong Wang, Beibei Sun, Hongyong Song, Huijing Yin, Jingyi Liu, Yadi Wu, Hanguang Zhu, Binhua P. Zhou, Jiong Deng, Zhiyuan Zhang

Markey Cancer Center Faculty Publications

Salivary adenoid cystic carcinoma (SACC) is characterized by invasive local growth and a high incidence of lung metastasis. Patients with lung metastasis have a poor prognosis. Treatment of metastatic SACC has been unsuccessful, largely due to a lack of specific targets for the metastatic cells. In this study, we showed that epidermal growth factor receptors (EGFR) were constitutively activated in metastatic lung subtypes of SACC cells, and that this activation was induced by autocrine expression of epiregulin (EREG), a ligand of EGFR. Autocrine EREG expression was increased in metastatic SACC-LM cells compared to that in non-metastatic parental SACC cells. Importantly, …

Targeting Wnt/Β-Catenin Pathway In Hepatocellular Carcinoma Treatment, Valery Vilchez, Lilia M. Turcios, Francesc Marti, Roberto Gedaly

Surgery Faculty Publications

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Liver cancer is generally related to hepatitis B or C infection and cirrhosis. Usually, patients with HCC are asymptomatic and are diagnosed at late stages when surgical treatment is no longer suitable. Limited treatment options for patients with advanced HCC are a major concern. Therefore, there is an urge for finding novel therapies to treat HCC. Liver cancer is highly heterogeneous and involved deregulation of several signaling pathways. Wnt/β-catenin pathway is frequently upregulated in HCC and it is implicated in maintenance of tumor initiating cells, drug …

Elucidating Proteasome Catalytic Subunit Composition And Its Role In Proteasome Inhibitor Resistance, Kimberly C. Carmony

Theses and Dissertations--Pharmacy

Proteasome inhibitors bortezomib and carfilzomib are FDA-approved anticancer agents that have contributed to significant improvements in treatment outcomes. However, the eventual onset of acquired resistance continues to limit their clinical utility, yet a clear consensus regarding the underlying mechanisms has not been reached.

Bortezomib and carfilzomib are known to target both the constitutive proteasome and the immunoproteasome, two conventional proteasome subtypes comprising distinctive sets of catalytic subunits. While it has become increasingly evident that additional, ‘intermediate’ proteasome subtypes, which harbor non-standard mixtures of constitutive proteasome and immunoproteasome catalytic subunits, represent a considerable proportion of the proteasome population in many cell …

Integrin Α6Β4 Promotes Pancreatic Cancer Invasion By Altering Dna Repair-Mediated Epigenetics, Brittany L. Carpenter

Theses and Dissertations--Molecular and Cellular Biochemistry

Integrin α6β4 is upregulated in pancreatic carcinoma, where signaling promotes metastatic properties, in part by altering the transcriptome. Such alterations can be accomplished through DNA demethylation of specific promoters, as seen with the pro-metastatic gene S100A4. I found that signaling from integrin α6β4 dramatically upregulates expression of amphiregulin (AREG) and epiregulin (EREG), ligands for the epidermal growth factor receptor (EGFR), and that these ligands promote pancreatic carcinoma invasion. To determine if AREG and EREG are regulated by DNA methylation, pancreatic cancer cells with low AREG and EREG expression were treated with the DNA methyltransferase inhibitor 5-aza-2’-deoxycytidine (5-Aza-CdR), resulting in stable …

Overcoming Treatment Resistance In Heterogeneous Tumors, Nikhil Hebbar

Theses and Dissertations--Toxicology and Cancer Biology

Most primary tumors are heterogeneous and are often composed of therapy-sensitive and emerging therapy-resistant cancer cells. Rather unexpectedly, treatment of therapy-sensitive tumor cells in heterogeneous tumor microenvironments resulted in apoptosis of the therapy-resistant cancer cells. We identified a novel Par-4 amino-terminal fragment (PAF, which includes amino acids 1-131 of Par-4) that is produced and released by therapy-sensitive cancer cells following therapy-induced caspase-dependent cleavage of the tumor suppressor Par-4. PAF caused paracrine apoptosis in therapy-resistant cancer cells. Unlike Par-4-inducible apoptosis, which is dependent on the cell surface GRP78 receptor, PAF produced cancer-selective apoptosis independent of cell surface GRP78 function. Par-4 contains …