Medicine and Health Sciences Commons^™

The Future Of Targeted Kinase Inhibitors In Melanoma, Signe Caksa, Usman Baqai, A E Aplin

Department of Cancer Biology Faculty Papers

Melanoma is a cancer of the pigment-producing cells of the body and its incidence is rising. Targeted inhibitors that act against kinases in the MAPK pathway are approved for BRAF-mutant metastatic cutaneous melanoma and increase patients' survival. Response to these therapies is limited by drug resistance and is less durable than with immune checkpoint inhibition. Conversely, rare melanoma subtypes have few therapeutic options for advanced disease and MAPK pathway targeting agents show minimal anti-tumor effects. Nevertheless, there is a future for targeted kinase inhibitors in melanoma: in new applications such as adjuvant or neoadjuvant therapy and in novel combinations with …

Targeting Sox10-Deficient Cells To Reduce The Dormant-Invasive Phenotype State In Melanoma, Claudia Capparelli, Timothy J. Purwin, Mckenna Glasheen, Signe Caksa, Manoela Tiago, Nicole A. Wilski, Danielle Pomante, Sheera Rosenbaum, Mai Q Nguyen, Weijia Cai, Janusz Franco-Barraza, R. Zheng, Md, Gaurav Kumar, I Chervoneva, Ayako Shimada, Vito W Rebecca, Adam E. Snook, Kim Hookim, Xiaowei Xu, Edna Cukierman, Meenhard Herlyn, A E Aplin

Department of Cancer Biology Faculty Papers

Cellular plasticity contributes to intra-tumoral heterogeneity and phenotype switching, which enable adaptation to metastatic microenvironments and resistance to therapies. Mechanisms underlying tumor cell plasticity remain poorly understood. SOX10, a neural crest lineage transcription factor, is heterogeneously expressed in melanomas. Loss of SOX10 reduces proliferation, leads to invasive properties, including the expression of mesenchymal genes and extracellular matrix, and promotes tolerance to BRAF and/or MEK inhibitors. We identify the class of cellular inhibitor of apoptosis protein-1/2 (cIAP1/2) inhibitors as inducing cell death selectively in SOX10-deficient cells. Targeted therapy selects for SOX10 knockout cells underscoring their drug tolerant properties. Combining cIAP1/2 inhibitor …

Ras-Mediated Tumor Stress Adaptation And The Targeting Opportunities It Presents, Alexandra Redding, A E Aplin, Elda Grabocka

Department of Cancer Biology Faculty Papers

Cellular stress is known to function in synergistic cooperation with oncogenic mutations during tumorigenesis to drive cancer progression. Oncogenic RAS is a strong inducer of a variety of pro-tumorigenic cellular stresses, and also enhances the ability of cells to tolerate these stresses through multiple mechanisms. Many of these oncogenic, RAS-driven, stress-adaptive mechanisms have also been implicated in tolerance and resistance to chemotherapy and to therapies that target the RAS pathway. Understanding how oncogenic RAS shapes cellular stress adaptation and how this functions in drug resistance is of vital importance for identifying new therapeutic targets and therapeutic combinations to treat RAS-driven …

Novel Oncogenic Transcription Factor Cooperation In Rb-Deficient Cancer, Amy C. Mandigo, Ayesha A Shafi, Jennifer J Mccann, Wei Yuan, Talya Laufer, Denisa Bogdan, Lewis Gallagher, Emanuela Dylgjeri, Galina Semenova, Irina A Vasilevskaya, M J Schiewer, Chris M Mcnair, Johann S De Bono, Karen E Knudsen

Department of Cancer Biology Faculty Papers

The retinoblastoma tumor suppressor (RB) is a critical regulator of E2F-dependent transcription, controlling a multitude of protumorigenic networks including but not limited to cell-cycle control. Here, genome-wide assessment of E2F1 function after RB loss in isogenic models of prostate cancer revealed unexpected repositioning and cooperation with oncogenic transcription factors, including the major driver of disease progression, the androgen receptor (AR). Further investigation revealed that observed AR/E2F1 cooperation elicited novel transcriptional networks that promote cancer phenotypes, especially as related to evasion of cell death. These observations were reflected in assessment of human disease, indicating the clinical relevance of the AR/E2F1 cooperome …

Sox10 Requirement For Melanoma Tumor Growth Is Due, In Part, To Immune-Mediated Effects, Sheera Rosenbaum, Manoela Tiago, Signe Caksa, Claudia Capparelli, Timothy J. Purwin, Gaurav Kumar, Mckenna Glasheen, Danielle Pomante, Daniel Kotas, I Chervoneva, A E Aplin

Department of Cancer Biology Faculty Papers

Developmental factors may regulate the expression of immune modulatory proteins in cancer, linking embryonic development and cancer cell immune evasion. This is particularly relevant in melanoma because immune checkpoint inhibitors are commonly used in the clinic. SRY-box transcription factor 10 (SOX10) mediates neural crest development and is required for melanoma cell growth. In this study, we investigate immune-related targets of SOX10 and observe positive regulation of herpesvirus entry mediator (HVEM) and carcinoembryonic-antigen cell-adhesion molecule 1 (CEACAM1). Sox10 knockout reduces tumor growth in vivo, and this effect is exacerbated in immune-competent models. Modulation of CEACAM1 expression but not HVEM elicits modest …

'Educated' Osteoblasts Reduce Osteoclastogenesis In A Bone-Tumor Mimetic Microenvironment., Alexus D. Kolb, Jinlu Dai, Evan T. Keller, Karen M. Bussard

Department of Cancer Biology Faculty Papers

Breast cancer (BC) metastases to bone disrupt the balance between osteoblasts and osteoclasts, leading to excessive bone resorption. We identified a novel subpopulation of osteoblasts with tumor-inhibitory properties, called educated osteoblasts (EOs). Here we sought to examine the effect of EOs on osteoclastogenesis during tumor progression. We hypothesized that EOs affect osteoclast development in the bone-tumor niche, leading to suppressed pre-osteoclast fusion and bone resorption. Conditioned media (CM) was analyzed for protein expression of osteoclast factors receptor activator of nuclear factor kappa-β ligand (RANKL), osteoprotegerin (OPG), and tumor necrosis factor alpha (TNFα) via ELISA. EOs were co-cultured with pre-osteoclasts on …

The Membrane-Associated Form Of Cyclin D1 Enhances Cellular Invasion, Ke Chen, Xuanmao Jiao, Anthony Ashton, Agnese Di Rocco, Timothy G Pestell, Yunguang Sun, Jun Zhao, Mathew C Casimiro, Zhiping Li, Michael P Lisanti, Peter Mccue, Duanwen Shen, Samuel Achilefu, Hallgeir Rui, Richard G Pestell

Department of Cancer Biology Faculty Papers

The essential G1-cyclin, CCND1, is a collaborative nuclear oncogene that is frequently overexpressed in cancer. D-type cyclins bind and activate CDK4 and CDK6 thereby contributing to G1-S cell-cycle progression. In addition to the nucleus, herein cyclin D1 was also located in the cytoplasmic membrane. In contrast with the nuclear-localized form of cyclin D1 (cyclin D1NL), the cytoplasmic membrane-localized form of cyclin D1 (cyclin D1MEM) induced transwell migration and the velocity of cellular migration. The cyclin D1MEM was sufficient to induce G1-S cell-cycle progression, cellular proliferation, and colony formation. The cyclin D1MEM was sufficient to induce phosphorylation of the serine threonine …

Endogenous Cyclin D1 Promotes The Rate Of Onset And Magnitude Of Mitogenic Signaling Via Akt1 Ser473 Phosphorylation., Ke Chen, Xuanmao Jiao, Agnese Di Rocco, Duanwen Shen, Shaohua Xu, Adam Ertel, Zuoren Yu, Gabriele Di Sante, Min Wang, Zhiping Li, Timothy G Pestell, Mathew C Casimiro, Emmanuel Skordalakes, Samuel Achilefu, Richard G Pestell

Department of Cancer Biology Faculty Papers

Cyclin D1 encodes the regulatory subunit of a holoenzyme that phosphorylates RB and functions as a collaborative nuclear oncogene. The serine threonine kinase Akt plays a pivotal role in the control of cellular metabolism, survival, and mitogenic signaling. Herein, Akt1-mediated phosphorylation of downstream substrates in the mammary gland is reduced by cyclin D1 genetic deletion and is induced by mammary-gland-targeted cyclin D1 overexpression. Cyclin D1 is associated with Akt1 and augments the rate of onset and maximal cellular Akt1 activity induced by mitogens. Cyclin D1 is identified in a cytoplasmic-membrane-associated pool, and cytoplasmic-membrane-localized cyclin D1-but not nuclear-localized cyclin D1-recapitulates Akt1 …

Interaction Of The Oncoprotein Transcription Factor Myc With Its Chromatin Cofactor Wdr5 Is Essential For Tumor Maintenance., Lance R. Thomas, Clare M. Adams, Jing Wang, April M. Weissmiller, Joy Creighton, Shelly L. Lorey, Qi Liu, Stephen W. Fesik, Christine M. Eischen, William P. Tansey

Department of Cancer Biology Faculty Papers

The oncoprotein transcription factor MYC is overexpressed in the majority of cancers. Key to its oncogenic activity is the ability of MYC to regulate gene expression patterns that drive and maintain the malignant state. MYC is also considered a validated anticancer target, but efforts to pharmacologically inhibit MYC have failed. The dependence of MYC on cofactors creates opportunities for therapeutic intervention, but for any cofactor this requires structural understanding of how the cofactor interacts with MYC, knowledge of the role it plays in MYC function, and demonstration that disrupting the cofactor interaction will cause existing cancers to regress. One cofactor …

Identification Of Monocyte-Like Precursors Of Granulocytes In Cancer As A Mechanism For Accumulation Of Pmn-Mdscs., Jérôme Mastio, Thomas Condamine, George Dominguez, Andrew V Kossenkov, Laxminarasimha Donthireddy, Filippo Veglia, Cindy Lin, Fang Wang, Shuyu Fu, Jie Zhou, Patrick Viatour, Sergio Lavilla-Alonso, Alexander T. Polo, Evgenii N. Tcyganov, Charles Mulligan, Brian Nam, Joseph Bennett, Gregory Masters, Michael Guarino, Amit Kumar, Yulia Nefedova, Robert H. Vonderheide, Lucia R. Languino, Scott I. Abrams, Dmitry I. Gabrilovich

Department of Cancer Biology Faculty Papers

We have identified a precursor that differentiates into granulocytes in vitro and in vivo yet belongs to the monocytic lineage. We have termed these cells monocyte-like precursors of granulocytes (MLPGs). Under steady state conditions, MLPGs were absent in the spleen and barely detectable in the bone marrow (BM). In contrast, these cells significantly expanded in tumor-bearing mice and differentiated to polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Selective depletion of monocytic cells had no effect on the number of granulocytes in naive mice but decreased the population of PMN-MDSCs in tumor-bearing mice by 50%. The expansion of MLPGs was found to be …

The Bone Extracellular Matrix As An Ideal Milieu For Cancer Cell Metastases., Alexus D. Kolb, Karen M. Bussard

Department of Cancer Biology Faculty Papers

Bone is a preferential site for cancer metastases, including multiple myeloma, prostate, and breast cancers.The composition of bone, especially the extracellular matrix (ECM), make it an attractive site for cancer cell colonization and survival. The bone ECM is composed of living cells embedded within a matrix composed of both organic and inorganic components. Among the organic components, type I collagen provides the tensile strength of bone. Inorganic components, including hydroxyapatite crystals, are an integral component of bone and provide bone with its rigidity. Under normal circumstances, two of the main cell types in bone, the osteoblasts and osteoclasts, help to …

M6a Mrna Demethylase Fto Regulates Melanoma Tumorigenicity And Response To Anti-Pd-1 Blockade, Seungwon Yang, Jiangbo Wei, Yan-Hong Cui, Gayoung Park, Palak Shah, Yu Deng, Andrew E. Aplin, Zhike Lu, Seungmin Hwang, Chuan He, Yu-Ying He

Department of Cancer Biology Faculty Papers

Melanoma is one of the most deadly and therapy-resistant cancers. Here we show that N⁶-methyladenosine (m⁶A) mRNA demethylation by fat mass and obesity-associated protein (FTO) increases melanoma growth and decreases response to anti-PD-1 blockade immunotherapy. FTO level is increased in human melanoma and enhances melanoma tumorigenesis in mice. FTO is induced by metabolic starvation stress through the autophagy and NF-κB pathway. Knockdown of FTO increases m⁶A methylation in the critical protumorigenic melanoma cell-intrinsic genes including PD-1 (PDCD1), CXCR4, and SOX10, leading to increased RNA decay through the m⁶A reader YTHDF2. Knockdown of …

Tumor-Derived Extracellular Vesicles Require Β1 Integrins To Promote Anchorage-Independent Growth., Rachel M. Derita, Aejaz Sayeed, Vaughn Garcia, Shiv Ram Krishn, Christopher D. Shields, Srawasti Sarker, Andrea Friedman, Peter Mccue, Sudheer Kumar Molugu, Ulrich Rodeck, Adam P. Dicker, Lucia R. Languino

Department of Cancer Biology Faculty Papers

The β1 integrins, known to promote cancer progression, are abundant in extracellular vesicles (EVs). We investigated whether prostate cancer (PrCa) EVs affect anchorage-independent growth and whether β1 integrins are required for this effect. Specifically using a cell-line-based genetic rescue and an in vivo PrCa model, we show that gradient-purified small EVs (sEVs) from either cancer cells or blood from tumor-bearing TRAMP (transgenic adenocarcinoma of the mouse prostate) mice promote anchorage-independent growth of PrCa cells. In contrast, sEVs from cultured PrCa cells harboring a short hairpin RNA to β1, from wild-type mice or from TRAMP mice carrying a β1 conditional ablation …

Mir-196b Target Screen Reveals Mechanisms Maintaining Leukemia Stemness With Therapeutic Potential., Sara E. Meyer, David E. Muench, Andrew M. Rogers, Tess J. Newkold, Emily Orr, Eric O'Brien, John P. Perentesis, John G. Doench, Ashish Lal, Patrick J. Morris, Craig J. Thomas, Judy Lieberman, Edwina Mcglinn, Bruce J. Aronow, Nathan Salomonis, H. Leighton Grimes

Department of Cancer Biology Faculty Papers

We have shown that antagomiR inhibition of miRNA miR-21 and miR-196b activity is sufficient to ablate MLL-AF9 leukemia stem cells (LSC) in vivo. Here, we used an shRNA screening approach to mimic miRNA activity on experimentally verified miR-196b targets to identify functionally important and therapeutically relevant pathways downstream of oncogenic miRNA in MLL-r AML. We found Cdkn1b (p27^Kip1) is a direct miR-196b target whose repression enhanced an embryonic stem cell–like signature associated with decreased leukemia latency and increased numbers of leukemia stem cells in vivo. Conversely, elevation of p27^Kip1 significantly reduced MLL-r leukemia self-renewal, promoted monocytic differentiation …

Syntaphilin Ubiquitination Regulates Mitochondrial Dynamics And Tumor Cell Movements., Jae Ho Seo, Ekta Agarwal, Kelly G. Bryant, M. Cecilia Caino, Eui Tae Kim, Andrew V. Kossenkov, Hsin-Yao Tang, Lucia R. Languino, Dmitry I. Gabrilovich, Andrew R. Cohen, David W. Speicher, Dario C. Altieri

Department of Cancer Biology Faculty Papers

Syntaphilin (SNPH) inhibits the movement of mitochondria in tumor cells, preventing their accumulation at the cortical cytoskeleton and limiting the bioenergetics of cell motility and invasion. Although this may suppress metastasis, the regulation of the SNPH pathway is not well understood. Using a global proteomics screen, we show that SNPH associates with multiple regulators of ubiquitin-dependent responses and is ubiquitinated by the E3 ligase CHIP (or STUB1) on Lys111 and Lys153 in the microtubule-binding domain. SNPH ubiquitination did not result in protein degradation, but instead anchored SNPH on tubulin to inhibit mitochondrial motility and cycles of organelle fusion and fission, …

Concurrent Regulation Of Lkb1 And Camkk2 In The Activation Of Ampk In Castrate-Resistant Prostate Cancer By A Well-Defined Polyherbal Mixture With Anticancer Properties., Amber F. Macdonald, Ahmed Bettaieb, Dallas R. Donohoe, Dina S. Alani, Anna Han, Yi Zhao, Jay Whelan

Department of Cancer Biology Faculty Papers

BACKGROUND: Zyflamend, a blend of herbal extracts, effectively inhibits tumor growth using preclinical models of castrate-resistant prostate cancer mediated in part by 5'-adenosine monophosphate-activated protein kinase (AMPK), a master energy sensor of the cell. Clinically, treatment with Zyflamend and/or metformin (activators of AMPK) had benefits in castrate-resistant prostate cancer patients who no longer responded to treatment. Two predominant upstream kinases are known to activate AMPK: liver kinase B1 (LKB1), a tumor suppressor, and calcium-calmodulin kinase kinase-2 (CaMKK2), a tumor promotor over-expressed in many cancers. The objective was to interrogate how Zyflamend activates AMPK by determining the roles of LKB1 and …

Cks1 Expression In Melanocytic Nevi And Melanoma, Anna A. Brożyna, Andrew Aplin, Cynthia Cohen, Grant Carlson, Andrew Joseph Page, Michael Murphy, Andrzej T. Slominski, J. Andrew Carlson

Department of Cancer Biology Faculty Papers

Cyclin-dependent kinase subunit 1 (Cks1) regulates the degradation of p27, an important G1-S inhibitor, which is up regulated by MAPK pathway activation. In this study, we sought to determine whether Cks1 expression is increased in melanocytic tumors and correlates with outcome and/or other clinicopathologic prognostic markers. Cks1 expression was assessed by immunohistochemistry in 298 melanocytic lesions. The frequency and intensity of cytoplasmic and nuclear expression was scored as a labeling index and correlated with clinico-pathological data. Nuclear Cks1 protein was found in 63% of melanocytic nevi, 89% primary and 90% metastatic melanomas with mean labeling index of 7 ± 16, …

Mdm2 Is Required For Survival And Growth Of P53-Deficient Cancer Cells., Kyle P Feeley, Clare M. Adams, Ramkrishna Mitra, Christine M. Eischen

Department of Cancer Biology Faculty Papers

p53 deletion prevents the embryonic lethality of normal tissues lacking Mdm2, suggesting that cells can survive without Mdm2 if p53 is also absent. Here we report evidence challenging this view, with implications for therapeutically targeting Mdm2. Deletion of Mdm2 in T-cell lymphomas or sarcomas lacking p53 induced apoptosis and G₂ cell-cycle arrest, prolonging survival of mice with these tumors. p53^-/- fibroblasts showed similar results, indicating that the effects of Mdm2 loss extend to pre-malignant cells. Mdm2 deletion in p53^-/- cells upregulated p53 transcriptional target genes that induce apoptosis and cell-cycle arrest. Mdm2 deletion also increased levels of …

Suppression Of Invasion And Metastasis Of Triple-Negative Breast Cancer Lines By Pharmacological Or Genetic Inhibition Of Slug Activity., Giovanna Ferrari-Amorotti, Claudia Chiodoni, Fei Shen, Sara Cattelani, Angela Rachele Soliera, Gloria Manzotti, Giulia Grisendi, Massimo Dominici, Francesco Rivasi, Mario Paolo Colombo, Alessandro Fatatis, Bruno Calabretta

Department of Cancer Biology Faculty Papers

Most triple-negative breast cancers (TNBCs) exhibit gene expression patterns associated with epithelial-to-mesenchymal transition (EMT), a feature that correlates with a propensity for metastatic spread. Overexpression of the EMT regulator Slug is detected in basal and mesenchymal-type TNBCs and is associated with reduced E-cadherin expression and aggressive disease. The effects of Slug depend, in part, on the interaction of its N-terminal SNAG repressor domain with the chromatin-modifying protein lysine demethylase 1 (LSD1); thus, we investigated whether tranylcypromine [also known as trans-2-phenylcyclopropylamine hydrochloride (PCPA) or Parnate], an inhibitor of LSD1 that blocks its interaction with Slug, suppresses the migration, invasion, and metastatic …

Mir-17/20 Sensitization Of Breast Cancer Cells To Chemotherapy-Induced Apoptosis Requires Akt1., Zuoren Yu, Zengguang Xu, Gabriele Disante, Jennifer Wright, Min Wang, Yuan Li, Qian Zhao, Tao Ren, Xiaoming Ju, Ellen Gutman, Guangxue Wang, Sankar Addya, Tieyan Li, Zhendong Xiang, Chenguang Wang, Xiongfei Yang, Xiaolai Yang, Richard Pestell

Department of Cancer Biology Faculty Papers

The serine threonine kinase Akt1 has been implicated in the control of cellular metabolism, survival and growth. Herein, disruption of the ubiquitously expressed member of the Akt family of genes, Akt1, in the mouse, demonstrates a requirement for Akt1 in miRNA-mediated cellular apoptosis. The miR-17/20 cluster is known to inhibit breast cancer cellular proliferation through G1/S cell cycle arrest via binding to the cyclin D1 3'UTR. Here we show that miR-17/20 overexpression sensitizes cells to apoptosis induced by either Doxorubicin or UV irradiation in MCF-7 cells via Akt1. miR-17/20 mediates apoptosis via increased p53 expression which promotes Akt degradation. Akt1-/- …

Single Nucleotide Polymorphism Of Srebf-1 Gene Associated With An Increased Risk Of Endometrial Cancer In Chinese Women., Chun-Ping Qiu, Qing-Tao Lv, Samina Dongol, Chenguang Wang, Jie Jiang

Department of Cancer Biology Faculty Papers

AIM: Elevated levels of sterol regulatory element-binding protein-1 (SREBP-1) have been found in endometrial cancer (EC), suggesting that it is essential to the development of EC. Obesity and diabetes have been established as known risk factors of EC, while SREBF-1 gene polymorphisms have also been found to be associated with obesity and type II diabetes. Therefore, we hypothesize that single nucleotide polymorphism (SNP) in SREBF-1 gene may be associated with increased risk of EC.

METHOD: We analyzed the sequence of SREBF-1 in tissue samples from 30 EC cases and 6 benign controls using high throughput method. Based on the primary …

Depletion Of Pre-Mrna Splicing Factor Cdc5l Inhibits Mitotic Progression And Triggers Mitotic Catastrophe., R Mu, Y-B Wang, M Wu, Y Yang, W Song, T Li, W-N Zhang, B Tan, A-L Li, N Wang, Q Xia, W-L Gong, Chenguang Wang, T Zhou, N Guo, Z-H Sang, H-Y Li

Department of Cancer Biology Faculty Papers

Disturbing mitotic progression via targeted anti-mitotic therapy is an attractive strategy for cancer treatment. Therefore, the exploration and elucidation of molecular targets and pathways in mitosis are critical for the development of anti-mitotic drugs. Here, we show that cell division cycle 5-like (Cdc5L), a pre-mRNA splicing factor, is a regulator of mitotic progression. Depletion of Cdc5L causes dramatic mitotic arrest, chromosome misalignments and sustained activation of spindle assembly checkpoint, eventually leading to mitotic catastrophe. Moreover, these defects result from severe impairment of kinetochore-microtubule attachment and serious DNA damage. Genome-wide gene expression analysis reveals that Cdc5L modulates the expression of a …

Inflammation, Organomegaly, And Muscle Wasting Despite Hyperphagia In A Mouse Model Of Burn Cachexia., Felipe E Pedroso, Paul B Spalding, Michael C Cheung, Relin Yang, Juan C Gutierrez, Andrea Bonetto, Rui Zhan, Ho Lam Chan, Nicholas Namias, Leonidas G Koniaris, Teresa A Zimmers

Department of Cancer Biology Faculty Papers

BACKGROUND: Burn injury results in a chronic inflammatory, hypermetabolic, and hypercatabolic state persisting long after initial injury and wound healing. Burn survivors experience a profound and prolonged loss of lean body mass, fat mass, and bone mineral density, associated with significant morbidity and reduced quality of life. Understanding the mechanisms responsible is essential for developing therapies. A complete characterization of the pathophysiology of burn cachexia in a reproducible mouse model was lacking.

METHODS: Young adult (12-16 weeks of age) male C57BL/6J mice were given full thickness burns using heated brass plates or sham injury. Food and water intake, organ and …

Regulation Of Lipogenesis By Cyclin-Dependent Kinase 8-Mediated Control Of Srebp-1., Xiaoping Zhao, Daorong Feng, Qun Wang, Arian Abdulla, Xiao-Jun Xie, Jie Zhou, Yan Sun, Ellen S Yang, Lu-Ping Liu, Bhavapriya Vaitheesvaran, Lauren Bridges, Irwin J Kurland, Randy Strich, Jian-Quan Ni, Chenguang Wang, Johan Ericsson, Jeffrey E Pessin, Jun-Yuan Ji, Fajun Yang

Department of Cancer Biology Faculty Papers

Altered lipid metabolism underlies several major human diseases, including obesity and type 2 diabetes. However, lipid metabolism pathophysiology remains poorly understood at the molecular level. Insulin is the primary stimulator of hepatic lipogenesis through activation of the SREBP-1c transcription factor. Here we identified cyclin-dependent kinase 8 (CDK8) and its regulatory partner cyclin C (CycC) as negative regulators of the lipogenic pathway in Drosophila, mammalian hepatocytes, and mouse liver. The inhibitory effect of CDK8 and CycC on de novo lipogenesis was mediated through CDK8 phosphorylation of nuclear SREBP-1c at a conserved threonine residue. Phosphorylation by CDK8 enhanced SREBP-1c ubiquitination and protein …

Genetic Ablation Of Cav1 Differentially Affects Melanoma Tumor Growth And Metastasis In Mice: Role Of Cav1 In Shh Heterotypic Signaling And Transendothelial Migration., Franco Capozza, Casey Trimmer, Remedios Castello-Cros, Sanjay Katiyar, Diana Whitaker-Menezes, Antonia Follenzi, Marco Crosariol, Gemma Llaverias, Federica Sotgia, Richard G Pestell, Michael P Lisanti

Department of Cancer Biology Faculty Papers

Both cell-autonomous and non-cell-autonomous factors contribute to tumor growth and metastasis of melanoma. The function of caveolin-1 (Cav1), a multifunctional scaffold protein known to modulate several biologic processes in both normal tissue and cancer, has been recently investigated in melanoma cancer cells, but its role in the melanoma microenvironment remains largely unexplored. Here, we show that orthotopic implantation of B16F10 melanoma cells in the skin of Cav1KO mice increases tumor growth, and co-injection of Cav1-deficient dermal fibroblasts with melanoma cells is sufficient to recapitulate the tumor phenotype observed in Cav1KO mice. Using indirect coculture experiments with fibroblasts and melanoma cells …

Cyclin D1 Induces Chromosomal Instability., Mathew C Casimiro, Richard Pestell

Department of Cancer Biology Faculty Papers

We developed mouse model systems to investigate the potential for cyclin D1 to induce CIN in vivo. In a mammary gland specific Tet-inducible model the acute expression profile regulated by cyclin D1 after 7 days was enriched in genes that rank highly with CIN. We also used a mammary gland targeted model (MMTV) to continuously express cyclin D1. The mice started to develop mammary gland tumors at 400 days and the tumor-free incidence was 40% in MMTV-cyclin D1. The gene expression profile of the tumors showed enrichment for the CIN signature. We next compared cyclin D1 expression and the highest …

Aleuria Aurantia Lectin (Aal)-Reactive Immunoglobulin G Rapidly Appears In Sera Of Animals Following Antigen Exposure., Songming Chen, Chen Lu, Hongbo Gu, Anand Mehta, Jianwei Li, Patrick B Romano, David Horn, D Craig Hooper, Carthene R Bazemore-Walker, Timothy Block

Department of Cancer Biology Faculty Papers

We have discovered an Aleuria Aurantia Lectin (AAL)-reactive immunoglobulin G (IgG) that naturally occurs in the circulation of rabbits and mice, following immune responses induced by various foreign antigens. AAL can specifically bind to fucose moieties on glycoproteins. However, most serum IgGs are poorly bound by AAL unless they are denatured or treated with glycosidase. In this study, using an immunogen-independent AAL-antibody microarray assay that we developed, we detected AAL-reactive IgG in the sera of all animals that had been immunized 1-2 weeks previously with various immunogens with and without adjuvants and developed immunogen-specific responses. All of these animals subsequently …

Aleuria Aurantia Lectin (Aal)-Reactive Immunoglobulin G Rapidly Appears In Sera Of Animals Following Antigen Exposure., Songming Chen, Chen Lu, Hongbo Gu, Anand Mehta, Jianwei Li, Patrick B Romano, David Horn, D Craig Hooper, Carthene R Bazemore-Walker, Timothy Block

Department of Cancer Biology Faculty Papers

We have discovered an Aleuria Aurantia Lectin (AAL)-reactive immunoglobulin G (IgG) that naturally occurs in the circulation of rabbits and mice, following immune responses induced by various foreign antigens. AAL can specifically bind to fucose moieties on glycoproteins. However, most serum IgGs are poorly bound by AAL unless they are denatured or treated with glycosidase. In this study, using an immunogen-independent AAL-antibody microarray assay that we developed, we detected AAL-reactive IgG in the sera of all animals that had been immunized 1-2 weeks previously with various immunogens with and without adjuvants and developed immunogen-specific responses. All of these animals subsequently …

Differential Impact Of Tumor Suppressor Pathways On Dna Damage Response And Therapy-Induced Transformation In A Mouse Primary Cell Model., A Kathleen Mcclendon, Jeffry L Dean, Adam Ertel, Erik S Knudsen

Department of Cancer Biology Faculty Papers

The RB and p53 tumor suppressors are mediators of DNA damage response, and compound inactivation of RB and p53 is a common occurrence in human cancers. Surprisingly, their cooperation in DNA damage signaling in relation to tumorigenesis and therapeutic response remains enigmatic. In the context of individuals with heritable retinoblastoma, there is a predilection for secondary tumor development, which has been associated with the use of radiation-therapy to treat the primary tumor. Furthermore, while germline mutations of the p53 gene are critical drivers for cancer predisposition syndromes, it is postulated that extrinsic stresses play a major role in promoting varying …

The Production Of Antibody By Invading B Cells Is Required For The Clearance Of Rabies Virus From The Central Nervous System., D Craig Hooper, Timothy W Phares, Marzena J Fabis, Anirban Roy

Department of Cancer Biology Faculty Papers

BACKGROUND: The pathogenesis of rabies is associated with the inability to deliver immune effectors across the blood-brain barrier and to clear virulent rabies virus from CNS tissues. However, the mechanisms that facilitate immune effector entry into CNS tissues are induced by infection with attenuated rabies virus.

METHODOLOGY/PRINCIPAL FINDINGS: Infection of normal mice with attenuated rabies virus but not immunization with killed virus can promote the clearance of pathogenic rabies virus from the CNS. T cell activity in B cell-deficient mice can control the replication of attenuated virus in the CNS, but viral mRNA persists. Low levels of passively administered rabies …