Biochemistry, Biophysics, and Structural Biology Commons^™

Metabolic Reprogramming Driven By Ezh2 Inhibition Depends On Cell–Matrix Interactions, Teresa W-M Fan, Jahid M. M. Islam, Richard M. Higashi, Penghui Lin, Christine F. Brainson, Andrew N. Lane

Markey Cancer Center Faculty Publications

EZH2 (Enhancer of Zeste Homolog 2), a subunit of Poly- comb Repressive Complex 2 (PRC2), catalyzes the trimethyla- tion of histone H3 at lysine 27 (H3K27me3), which represses expression of genes. It also has PRC2-independent functions, including transcriptional coactivation of oncogenes, and is frequently overexpressed in lung cancers. Clinically, EZH2 in- hibition can be achieved with the FDA-approved drug EPZ- 6438 (tazemetostat). To realize the full potential of EZH2 blockade, it is critical to understand how cell-cell/cell-matrix interactions present in 3D tissue and cell culture systems in- fluences this blockade in terms of growth-related metabolic functions. Here, we show that …

A Monoadduct Generating Ru(Ii) Complex Induces Ribosome Biogenesis Stress And Is A Molecular Mimic Of Phenanthriplatin, Richard Joseph Mitchell, Sarah M. Kriger, Alexander D. Fenton, Dmytro Havrylyuk, Ankit Pandeya, Yang Sun, Tami Smith, Jason E. Derouchey, David K. Heidary, Edith C. Glazer

Markey Cancer Center Faculty Publications

Ruthenium complexes are often investigated as potential replacements for platinum-based chemotherapeutics in hopes of identifying systems with improved tolerability in vivo and reduced susceptibility to cellular resistance mechanisms. Inspired by phenanthriplatin, a non-traditional platinum agent that contains only one labile ligand, monofunctional ruthenium polypyridyl agents have been developed, but until now, few demonstrated promising anticancer activity. Here we introduce a potent new scaffold, based on [Ru(tpy)(dip)Cl]Cl (tpy = 2,20:60,200-terpyridine and dip = 4,7-diphenyl-1,10-phenanthroline) in pursuit of effective Ru(II )-based monofunctional agents. Notably, the extension of the terpyridine at the 40 position with an aromatic ring resulted in a molecule that …

Bilirubin Levels Are Negatively Correlated With Adiposity In Obese Men And Women, And Its Catabolized Product, Urobilin, Is Positively Associated With Insulin Resistance, Zachary A. Kipp, Mei Xu, Evelyn A. Bates, Wang-Hsin Lee, Philip A. Kern, Terry D. Hinds Jr.

Markey Cancer Center Faculty Publications

Bilirubin levels in obese humans and rodents have been shown to be lower than in their lean counterparts. Some studies have proposed that the glucuronyl UGT1A1 enzyme that clears bilirubin from the blood increases in the liver with obesity. UGT1A1 clearance of bilirubin allows more conjugated bilirubin to enter the intestine, where it is catabolized into urobilin, which can be then absorbed via the hepatic portal vein. We hypothesized that when bilirubin levels are decreased, the urobilin increases in the plasma of obese humans, as compared to lean humans. To test this, we measured plasma levels of bilirubin and urobilin, …

Dysregulated Polycomb Repressive Complex 2 Contributes To Chronic Obstructive Pulmonary Disease By Rewiring Stem Cell Fate, Aria Byrd, Xufeng Qu, Alexsandr Lukyanchuk, Jinpeng Liu, Fan Chen, Kassandra J. Naughton, Tanner Ducote, Xiulong Song, Hannah Bowman, Yanming Zhao, Abigail R Edgin, Chi Wang, Jinze Liu, Christine Fillmore Brainson

Markey Cancer Center Faculty Publications

Aberrant lung cell differentiation is a hallmark of many lung diseases including chronic obstructive pulmonary disease (COPD). The EZH2-containing Polycomb Repressive Complex 2 (PRC2) regulates embryonic lung stem cell fate, but its role in adult lung is obscure. Histological analysis of patient tissues revealed that loss of PRC2 activity was correlated with aberrant bronchiolar cell differentiation in COPD lung. Histological and single-cell RNA-sequencing analyses showed that loss of EZH2 in mouse lung organoids led to lowered self- renewal capability, increased squamous morphological development, and marked shifts in progenitor cell populations. Evaluation of in vivo models revealed that heterozygosity of Ezh2 …

Extracellular Vesicle Distribution And Localization In Skeletal Muscle At Rest And Following Disuse Atrophy, Ahmed Ismaeel, Douglas W. Van Pelt, Zachary Hettinger, Xu Fu, Christopher I. Richards, Timothy A. Butterfield, Jonathan J. Petrocelli, Ivan J. Vechetti Jr., Amy L. Confides, Micah J. Drummond, Esther E. Dupont-Versteegden

Markey Cancer Center Faculty Publications

Background Skeletal muscle (SkM) is a large, secretory organ that produces and releases myokines that can have autocrine, paracrine, and endocrine effects. Whether extracellular vesicles (EVs) also play a role in the SkM adaptive response and ability to communicate with other tissues is not well understood. The purpose of this study was to investigate EV biogenesis factors, marker expression, and localization across cell types in the skeletal muscle. We also aimed to investigate whether EV concentrations are altered by disuse atrophy.

Methods To identify the potential markers of SkM‑derived EVs, EVs were isolated from rat serum using density gradient ultracentrifugation, …

Polycomb Deficiency Drives A Foxp2-High Aggressive State Targetable By Epigenetic Inhibitors, Fan Chen, Aria Byrd, Jinpeng Liu, Robert M. Flight, Tanner Ducote, Kassandra J. Naughton, Xiulong Song, Abigail R Edgin, Alexsandr Lukyanchuk, Danielle T. Dixon, Christian M. Gosser, Dave-Preston Esoe, Rani Jayswal, Stuart H. Orkin, Hunter N. B. Moseley, Chi Wang, Christine Fillmore Brainson

Markey Cancer Center Faculty Publications

Inhibitors of the Polycomb Repressive Complex 2 (PRC2) histone methyltransferase EZH2 are approved for certain cancers, but realizing their wider utility relies upon understanding PRC2 biology in each cancer system. Using a genetic model to delete Ezh2 in KRAS-driven lung adenocarcinomas, we observed that Ezh2 haplo-insufficient tumors were less lethal and lower grade than Ezh2 fully-insufficient tumors, which were poorly differentiated and metastatic. Using three-dimensional cultures and in vivo experiments, we determined that EZH2-deficient tumors were vulnerable to H3K27 demethylase or BET inhibitors. PRC2 loss/inhibition led to de-repression of FOXP2, a transcription factor that promotes migration and stemness, and FOXP2 …

Suppressing Hepatic Ugt1a1 Increases Plasma Bilirubin, Lowers Plasma Urobilin, Reorganizes Kinase Signaling Pathways And Lipid Species And Improves Fatty Liver Disease, Evelyn A. Bates, Zachary A. Kipp, Genesee J. Martinez, Olufunto O. Badmus, Mangala M. Soundarapandian, Donald Foster, Mei Xu, Justin F. Creeden, Jennifer R. Greer, Andrew J. Morris, David E. Stec, Terry D. Hinds Jr.

Markey Cancer Center Faculty Publications

Several population studies have observed lower serum bilirubin levels in patients with non-alcoholic fatty liver disease (NAFLD). Yet, treatments to target this metabolic phenotype have not been explored. Therefore, we designed an N-Acetylgalactosamine (GalNAc) labeled RNAi to target the enzyme that clears bilirubin from the blood, the UGT1A1 glucuronyl enzyme (GNUR). In this study, male C57BL/6J mice were fed a high-fat diet (HFD, 60%) for 30 weeks to induce NAFLD and were treated subcutaneously with GNUR or sham (CTRL) once weekly for six weeks while continuing the HFD. The results show that GNUR treatments significantly raised plasma bilirubin levels and …

The Link Between Intracellular Calcium Signaling And Exosomal Pd-L1 In Cancer Progression And Immunotherapy, Rakibul Alam, Mizanur Rahman, Zhiguo Li

Markey Cancer Center Faculty Publications

Exosomes are small membrane vesicles containing microRNA, RNA, DNA fragments, and proteins that are transferred from donor cells to recipient cells. Tumor cells release exo- somes to reprogram the factors associated with the tumor microenvironment (TME) causing tu- mor metastasis and immune escape. Emerging evidence revealed that cancer cell-derived exosomes carry immune inhibitory molecule program death ligand 1 (PD-L1) that binds with re- ceptor program death protein 1 (PD-1) and promote tumor progression by escaping immune response. Currently, some FDA-approved monoclonal antibodies are clinically used for cancer treatment by blocking PD-1/PD-L1 interaction. Despite notable treatment outcomes, some pa- tients show …

Cell-Intrinsic Melanin Fails To Protect Melanocytes From Ultraviolet-Mutagenesis In The Absence Of Epidermal Melanin, Tirzah J. Weiss, Emma R. Crawford, Valentina Posada, Hafeez Rahman, Tong Liu, Brandon M. Murphy, Tiffany E. Arnold, Shannon Gray, Zhexuan Hu, Rebecca C. Hennessey, Lianbo Yu, John August D'Orazio, Craig J. Burd, Jonathan H. Zippin, Douglas Grossman, Christin E. Burd

Markey Cancer Center Faculty Publications

Melanin is a free-radical scavenger, antioxidant, and broadband absorber of ultraviolet (UV) radiation which protects the skin from environmental carcinogenesis. However, melanin synthesis and UV-induced reactive melanin species are also implicated in melanocyte genotoxicity. Here, we attempted to reconcile these disparate functions of melanin using a UVB- sensitive, NRAS-mutant mouse model, TpN. We crossed TpN mice heterozygous for an inactivating mutation in Tyrosinase to produce albino and black littermates on a C57BL/6J background. These animals were then exposed to a single UVB dose on postnatal day three when keratinocytes in the skin have yet to be melanized. Approximately one-third (35%) …

P70s6k1 (S6k1)-Mediated Phosphorylation Regulates Phosphatidylinositol 4-Phosphate 5-Kinase Type I Γ Degradation And Cell Invasion, Naser Jafari, Qiaodan Zheng, Liqing Li, Wei Li, Lei Qi, Jianyong Xiao, Tianyan Gao, Cai Huang

Markey Cancer Center Faculty Publications

Phosphatidylinositol 4-phosphate 5-kinase type I γ (PIPKIγ90) ubiquitination and subsequent degradation regulate focal adhesion assembly, cell migration, and invasion. However, it is unknown how upstream signals control PIPKIγ90 ubiquitination or degradation. Here we show that p70S6K1 (S6K1), a downstream target of mechanistic target of rapamycin (mTOR), phosphorylates PIPKIγ90 at Thr-553 and Ser-555 and that S6K1-mediated PIPKIγ90 phosphorylation is essential for cell migration and invasion. Moreover, PIPKIγ90 phosphorylation is required for the development of focal adhesions and invadopodia, key machineries for cell migration and invasion. Surprisingly, substitution of Thr-553 and Ser-555 …

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 …

Ubr3, A Novel Modulator Of Hh Signaling Affects The Degradation Of Costal-2 And Kif7 Through Poly-Ubiquitination, Tongchao Li, Junkai Fan, Bernardo Blanco-Sánchez, Nikolaos Giagtzoglou, Guang Lin, Shinya Yamamoto, Manish Jaiswal, Kuchuan Chen, Jie Zhang, Wei Wei, Michael T. Lewis, Andrew K. Groves, Monte Westerfield, Jianhang Jia, Hugo J. Bellen

Markey Cancer Center Faculty Publications

Hedgehog (Hh) signaling regulates multiple aspects of metazoan development and tissue homeostasis, and is constitutively active in numerous cancers. We identified Ubr3, an E3 ubiquitin ligase, as a novel, positive regulator of Hh signaling in Drosophila and vertebrates. Hh signaling regulates the Ubr3-mediated poly-ubiquitination and degradation of Cos2, a central component of Hh signaling. In developing Drosophila eye discs, loss of ubr3 leads to a delayed differentiation of photoreceptors and a reduction in Hh signaling. In zebrafish, loss of Ubr3 causes a decrease in Shh signaling in the developing eyes, somites, and sensory neurons. However, not all tissues that require …

Sonic Hedgehog Dependent Phosphorylation By Ck1Α And Grk2 Is Required For Ciliary Accumulation And Activation Of Smoothened, Yongbin Chen, Noriaki Sasai, Guoqiang Ma, Tao Yue, Jianhang Jia, James Briscoe, Jin Jiang

Markey Cancer Center Faculty Publications

Hedgehog (Hh) signaling regulates embryonic development and adult tissue homeostasis through the GPCR-like protein Smoothened (Smo), but how vertebrate Smo is activated remains poorly understood. In Drosophila, Hh dependent phosphorylation activates Smo. Whether this is also the case in vertebrates is unclear, owing to the marked sequence divergence between vertebrate and Drosophila Smo (dSmo) and the involvement of primary cilia in vertebrate Hh signaling. Here we demonstrate that mammalian Smo (mSmo) is activated through multi-site phosphorylation of its carboxyl-terminal tail by CK1α and GRK2. Phosphorylation of mSmo induces its active conformation and simultaneously promotes its ciliary accumulation. We demonstrate that …