Medicine and Health Sciences Commons^™

Gsk3Β Inhibition Blocks Melanoma Cell/Host Interactions By Downregulating N-Cadherin Expression And Decreasing Fak Phosphorylation., Jobin K John, Kim H T Paraiso, Vito W Rebecca, Liliana P Cantini, Ethan V Abel, Nicholas Pagano, Eric Meggers, Rahel Mathew, Clemens Krepler, Victoria Izumi, Bin Fang, John M Koomen, Jane L Messina, Meenhard Herlyn, Keiran S M Smalley

Department of Cancer Biology Faculty Papers

This study addresses the role of glycogen synthase kinase (GSK)-3β signaling in the tumorigenic behavior of melanoma. Immunohistochemical staining revealed GSK3β to be focally expressed in the invasive portions of 12 and 33% of primary and metastatic melanomas, respectively. GSK3 inhibitors and small interfering RNA (siRNA) knockdown of GSK3β were found to inhibit the motile behavior of melanoma cells in scratch wound, three-dimensional collagen-implanted spheroid, and modified Boyden chamber assays. Functionally, inhibition of GSK3β signaling was found to suppress N-cadherin expression at the messenger RNA and protein levels, and was associated with decreased expression of the transcription factor Slug. Pharmacological …

Fak Is A Critical Regulator Of Neuroblastoma Liver Metastasis, Sora Lee, Jingbo Qiao, Pritha Paul, Kathleen L. O'Connor, B. Mark Evers, Dai H. Chung

Surgery Faculty Publications

Neuroblastomas express increased levels of gastrin-releasing peptide receptor (GRP-R). However, the exact molecular mechanisms involved in GRP-R-mediated cell signaling in neuroblastoma growth and metastasis are unknown. Here, we report that focal adhesion kinase (FAK), as a critical downstream target of GRP-R, is an important regulator of neuroblastoma tumorigenicity. We found that FAK expression correlates with GRP-R expression in human neuroblastoma sections and cell lines. GRP-R overexpression in SK-N-SH cells increased FAK, integrin α3 and β1 expressions and cell migration. These cells demonstrated flatter cell morphology with broad lamellae, in which intense FAK expression was localized to the leading edges of …

Necrostatin-1 Analogues: Critical Issues On The Specificity, Activity And In Vivo Use In Experimental Disease Models., N Takahashi, L Duprez, S Grootjans, A Cauwels, W Nerinckx, J B Duhadaway, V Goossens, R Roelandt, F Van Hauwermeiren, C Libert, W Declercq, N Callewaert, G C Prendergast, A Degterev, J Yuan, P Vandenabeele

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Necrostatin-1 (Nec-1) is widely used in disease models to examine the contribution of receptor-interacting protein kinase (RIPK) 1 in cell death and inflammation. We studied three Nec-1 analogs: Nec-1, the active inhibitor of RIPK1, Nec-1 inactive (Nec-1i), its inactive variant, and Nec-1 stable (Nec-1s), its more stable variant. We report that Nec-1 is identical to methyl-thiohydantoin-tryptophan, an inhibitor of the potent immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO). Both Nec-1 and Nec-1i inhibited human IDO, but Nec-1s did not, as predicted by molecular modeling. Therefore, Nec-1s is a more specific RIPK1 inhibitor lacking the IDO-targeting effect. Next, although Nec-1i was ∼100 × …

Trop-2 Inhibits Prostate Cancer Cell Adhesion To Fibronectin Through The Β1 Integrin-Rack1 Axis., Marco Trerotola, Jing Li, Saverio Alberti, Lucia R. Languino

Department of Cancer Biology Faculty Papers

Trop-2 is a transmembrane glycoprotein upregulated in several human carcinomas, including prostate cancer (PrCa). Trop-2 has been suggested to regulate cell-cell adhesion, given its high homology with the other member of the Trop family, Trop-1/EpCAM, and its ability to bind the tight junction proteins claudin-1 and claudin-7. However, a role for Trop-2 in cell adhesion to the extracellular matrix has never been postulated. Here, we show for the first time that Trop-2 expression in PrCa cells correlates with their aggressiveness. Using either shRNA-mediated silencing of Trop-2 in cells that endogenously express it, or ectopic expression of Trop-2 in cells that …

Inhibition Of Fatty Acid Synthase Attenuates Cd44-Associated Signaling And Reduces Metastasis In Colorectal Cancer, Yekaterina Y. Zaytseva, Piotr G. Rychahou, Pat Gulhati, Victoria Allison Elliott, William Conan Mustain, Kathleen O'Connor, Andrew J. Morris, Manjula Sunkara, Heidi L. Weiss, Eun Young Lee, B. Mark Evers

Markey Cancer Center Faculty Publications

Fatty acid synthase (FASN) and ATP-citrate lyase, key enzymes of de novo lipogenesis, are significantly upregulated and activated in many cancers and portend poor prognosis. Even though the role of lipogenesis in providing proliferative and survival advantages to cancer cells has been described, the impact of aberrant activation of lipogenic enzymes on cancer progression remains unknown. In this study, we found that elevated expression of FASN is associated with advanced stages of colorectal cancer (CRC) and liver metastasis, suggesting that it may play a role in progression of CRC to metastatic disease. Targeted inhibition of lipogenic enzymes abolished expression of …

Decorin-Mediated Inhibition Of Colorectal Cancer Growth And Migration Is Associated With E-Cadherin In Vitro And In Mice., Xiuli Bi, Nicole M Pohl, Zhibin Qian, George R Yang, Yuan Gou, Grace Guzman, Andre Kajdacsy-Balla, Renato V Iozzo, Wancai Yang

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Previous studies have shown that decorin expression is significantly reduced in colorectal cancer tissues and cancer cells, and genetic deletion of the decorin gene is sufficient to cause intestinal tumor formation in mice, resulting from a downregulation of p21, p27(kip1) and E-cadherin and an upregulation of β-catenin signaling [Bi,X. et al. (2008) Genetic deficiency of decorin causes intestinal tumor formation through disruption of intestinal cell maturation. Carcinogenesis, 29, 1435-1440]. However, the regulation of E-cadherin by decorin and its implication in cancer formation and metastasis is largely unknown. Using a decorin knockout mouse model (Dcn(-/-) mice) and manipulated expression of decorin …

Inflammatory Signaling Compromises Cell Responses To Interferon Alpha., W-C Huangfu, J Qian, C Liu, J Liu, A E Lokshin, D P Baker, H Rui, S Y Fuchs

Department of Cancer Biology Faculty Papers

Interferon alpha (IFNα) is widely used for treatment of melanoma and certain other malignancies. This cytokine as well as the related IFNβ exerts potent anti-tumorigenic effects; however, their efficacy in patients is often suboptimal. Here, we report that inflammatory signaling impedes the effects of IFNα/β. Melanoma cells can secrete pro-inflammatory cytokines that inhibit cellular responses to IFNα/β via activating the ligand-independent pathway for the phosphorylation and subsequent ubiquitination and accelerated degradation of the IFNAR1 chain of type I IFN receptor. Catalytic activity of the p38 protein kinase was required for IFNAR1 downregulation and inhibition of IFNα/β signaling induced by proinflammatory …

The Role Of Ezh2 In The Regulation Of The Activity Of Matrix Metalloproteinases In Prostate Cancer Cells., Yong Jae Shin, Jeong-Ho Kim

Biochemistry and Molecular Medicine Faculty Publications

Degradation of the extracellular matrix (ECM), a critical step in cancer metastasis, is determined by the balance between MMPs (matrix metalloproteinases) and their inhibitors TIMPs (tissue inhibitors of metalloproteinases). In cancer cells, this balance is shifted towards MMPs, promoting ECM degradation. Here, we show that EZH2 plays an active role in this process by repressing the expression of TIMP2 and TIMP3 in prostate cancer cells. The TIMP genes are derepressed by knockdown of EZH2 expression in human prostate cancer cells but repressed by overexpression of EZH2 in benign human prostate epithelial cells. EZH2 catalyzes H3K27 trimethylation and subsequent DNA methylation …

Erk2 Phosphorylation Of Serine 77 Regulates Bmf Pro-Apoptotic Activity., Y Shao, A E Aplin

Department of Cancer Biology Faculty Papers

B-cell lymphoma 2 (Bcl-2) homology 3 (BH3)-only proteins represent a class of pro-apoptotic factors that neutralize pro-survival Bcl-2 proteins, and, in some cases, directly activate Bax. The mechanisms of control and the role of BH3-only proteins, such as Bcl-2 like protein 11 extra large and Bad are well studied. By contrast, relatively little is known about the regulation and role of Bcl-2 modifying factor (Bmf). The B-RAF oncogene is mutated in ∼8% of human tumors. We have previously shown that Bmf is upregulated at the transcript level and is required for apoptosis induced by targeting B-RAF signaling in tumor cells …

Gene Expression Signatures Modulated By Epidermal Growth Factor Receptor Activation And Their Relationship To Cetuximab Resistance In Head And Neck Squamous Cell Carcinoma., Elana J Fertig, Qing Ren, Haixia Cheng, Hiromitsu Hatakeyama, Adam Dicker Md, Phd, Ulrich Rodeck, Michael Considine, Michael F Ochs, Christine H Chung

Department of Radiation Oncology Faculty Papers

BACKGROUND: Aberrant activation of signaling pathways downstream of epidermal growth factor receptor (EGFR) has been hypothesized to be one of the mechanisms of cetuximab (a monoclonal antibody against EGFR) resistance in head and neck squamous cell carcinoma (HNSCC). To infer relevant and specific pathway activation downstream of EGFR from gene expression in HNSCC, we generated gene expression signatures using immortalized keratinocytes (HaCaT) subjected to ligand stimulation and transfected with EGFR, RELA/p65, or HRASVal12D.

RESULTS: The gene expression patterns that distinguished the HaCaT variants and conditions were inferred using the Markov chain Monte Carlo (MCMC) matrix factorization algorithm Coordinated Gene Activity …