Mark Smith

All Publications

• Sol-moiety: Discovery of a water-soluble prodrug technology for enhanced oral bioavailability of insoluble therapeutics. Nature communications Karbasi, A. B., Barfuss, J. D., Morgan, T. C., Collins, D., Costenbader, D. A., Dennis, D. G., Hinman, A., Ko, K., Messina, C., Nguyen, K. C., Schugar, R. C., Stein, K. A., Williams, B. B., Xu, H., Annes, J. P., Smith, M. 2024; 15 (1): 8487

  Abstract

  Though conceptually attractive, the use of water-soluble prodrug technology to enhance oral bioavailability of highly insoluble small molecule therapeutics has not been widely adopted. In large part, this is due to the rapid enzymatic or chemical hydrolysis of prodrugs within the gastrointestinal tract, resulting in drug precipitation and no overall improvement in oral bioavailability relative to standard formulation strategies. We reasoned that an optimal water-soluble prodrug could be attained if the rate of prodrug hydrolysis were reduced to favor drug absorption rather than drug precipitation. In doing so, the rate of hydrolysis provides a pharmacokinetic control point for drug delivery. Herein, we report the discovery of a water-soluble promoiety (Sol-moiety) technology to optimize the oral bioavailability of highly insoluble small molecule therapeutics, possessing various functional groups, without the need for sophisticated, often toxic, lipid or organic solvent-based formulations. The power of the technology is demonstrated with marked pharmacokinetic improvement of the commercial drugs enzalutamide, vemurafenib, and paclitaxel. This led to a successful efficacy study of a water-soluble orally administered prodrug of paclitaxel in a mouse pancreatic tumor model.

  View details for DOI 10.1038/s41467-024-52793-6

  View details for PubMedID 39353935

• Identification of highly potent and selective HTRA1 inhibitors. Bioorganic & medicinal chemistry letters Dennis, D. G., Joo Sun, Y., Parsons, D. E., Mahajan, V. B., Smith, M. 2024: 129814

  Abstract

  High temperature requirement A serine peptidase 1 (HTRA1) is a serine protease involved in an array of signaling pathways. It is also responsible for the regulation of protein aggregates via refolding, translocation, and degradation. It has subsequently been found that runaway proteolytic HTRA1 activity plays a role in a variety of diseases, including Age-Related Macular Degeneration (AMD), osteoarthritis, and Rheumatoid Arthritis. Selective inhibition of serine protease HTRA1 therefore offers a promising new strategy for the treatment of these diseases. Herein we disclose structure-activity-relationship (SAR) studies which identify key interactions responsible for binding affinity of small molecule inhibitors to HTRA1. The study results in highly potent molecules with IC50's less than 15 nM and excellent selectivity following a screen of 35 proteases.

  View details for DOI 10.1016/j.bmcl.2024.129814

  View details for PubMedID 38815872

• Discovery of azaspirocyclic 1H-3,4,5-Trisubstitued pyrazoles as novel G2019S-LRRK2 selective kinase inhibitors. European journal of medicinal chemistry Leśniak, R. K., Nichols, R. J., Schonemann, M., Zhao, J., Gajera, C. R., Lam, G., Nguyen, K. C., Langston, J. W., Smith, M., Montine, T. J. 2022; 242: 114693

  Abstract

  Mutations in the Leucine Rich Repeat Protein Kinase 2 gene (LRRK2) are genetic predispositions for Parkinson's Disease, of which the G2019S (GS) missense mutation is the most common. GS-LRRK2 has a hyperactive kinase, and although numerous drug discovery programs have targeted the LRRK2 kinase, few have reached clinical trials. We recently reported on the discovery of a novel LRRK2 kinase inhibitor chemotype, 1H-pyrazole biaryl sulfonamides. Although both potent and selective GS-LRRK2 inhibitors, 1H-pyrazole biaryl sulfonamides are incapable of crossing the blood-brain barrier. Retaining the core 1H-pyrazole and focusing our efforts on a phenylsulfonamide bioisosteric replacement, we report the discovery and preliminary development of azaspirocyclic 1H-3,4,5-trisubstituted pyrazoles as potent and selective (>2000-fold) GS-LRRK2 kinase inhibitors capable of entering rodent brain. The compounds disclosed here present an excellent starting point for the development of more brain penetrant compounds.

  View details for DOI 10.1016/j.ejmech.2022.114693

  View details for PubMedID 36049274

• Targeting LRRK2 mutations in Parkinson's disease. Future medicinal chemistry Leśniak, R. K., Nichols, R. J., Smith, M., Montine, T. J. 2022

  View details for DOI 10.4155/fmc-2022-0102

  View details for PubMedID 35730403

• Discovery of 1H-Pyrazole Biaryl Sulfonamides as Novel G2019S-LRRK2 Kinase Inhibitors. ACS medicinal chemistry letters Lesniak, R. K., Nichols, R. J., Schonemann, M., Zhao, J., Gajera, C. R., Lam, G., Nguyen, K. C., Langston, J. W., Smith, M., Montine, T. J. 2022; 13 (6): 981-988

  Abstract

  G2019S (GS) is the most prevalent mutation in the leucine rich repeat protein kinase 2 gene (LRRK2), a genetic predisposition that is common for Parkinson's disease, as well as for some forms of cancer, and is a shared risk allele for Crohn's disease. GS-LRRK2 has a hyperactive kinase, and although numerous drug discovery programs have targeted LRRK2 kinase, few have reached clinical development. We report the discovery and preliminary development of an entirely novel structural class of potent and selective GS-LRRK2 kinase inhibitors: biaryl-1H-pyrazoles.

  View details for DOI 10.1021/acsmedchemlett.2c00116

  View details for PubMedID 35707141

• Discovery of G2019S-Selective Leucine Rich Repeat Protein Kinase 2 inhibitors with invivo efficacy. European journal of medicinal chemistry Lesniak, R. K., Nichols, R. J., Schonemann, M., Zhao, J., Gajera, C. R., Fitch, W. L., Lam, G., Nguyen, K. C., Smith, M., Montine, T. J. 1800; 229: 114080

  Abstract

  Mutations in the Leucine Rich Repeat Protein Kinase 2 gene (LRRK2) are the most common genetic causes of Parkinson's Disease (PD). The G2019S mutation is the most common inherited LRRK2 mutation, occurs in the kinase domain, and results in increased kinase activity. We report the discovery and development of compound 38, an indazole-based, G2019S-selective (>2000-fold vs. WT) LRRK2 inhibitor capable of entering rodent brain (Kp=0.5) and selectively inhibiting G2019S-LRRK2. The compounds disclosed herein present a starting point for further development of brain penetrant G2019S selective inhibitors that hopefully reduce lung phenotype side-effects and pave the way to providing a precision medicine for people with PD who carry the G2019S mutation.

  View details for DOI 10.1016/j.ejmech.2021.114080

  View details for PubMedID 34992038

• Nonbisphosphonate inhibitors of Plasmodium falciparum FPPS/GGPPS. Bioorganic & medicinal chemistry letters Kabeche, S., Aida, J., Akther, T., Ichikawa, T., Ochida, A., Pulkoski-Gross, M. J., Smith, M., Humphries, P. S., Yeh, E. 2021: 127978

  Abstract

  A series of novel thiazole-containing amides were synthesized. A structure-activity relationship study of these compounds led to the identification of potent and selective PfFPPS/GGPPS inhibitors with good in vitro ADME profiles. The most promising candidate molecules were progressed to mouse in vivo PK studies and demonstrated adequate free drug exposure to warrant further investigation.

  View details for DOI 10.1016/j.bmcl.2021.127978

  View details for PubMedID 33766764

• Peptidomimetics Therapeutics for Retinal Disease. Biomolecules Parsons, D. E., Lee, S. H., Sun, Y. J., Velez, G., Bassuk, A. G., Smith, M., Mahajan, V. B. 2021; 11 (3)

  Abstract

  Ocular disorders originating in the retina can result in a partial or total loss of vision, making drug delivery to the retina of vital importance. However, effectively delivering drugs to the retina remains a challenge for ophthalmologists due to various anatomical and physicochemical barriers in the eye. This review introduces diverse administration routes and the accordant pharmacokinetic profiles of ocular drugs to aid in the development of safe and efficient drug delivery systems to the retina with a focus on peptidomimetics as a growing class of retinal drugs, which have great therapeutic potential and a high degree of specificity. We also discuss the pharmacokinetic profiles of small molecule drugs due to their structural similarity to small peptidomimetics. Lastly, various formulation strategies are suggested to overcome pharmacokinetic hurdles such as solubility, retention time, enzymatic degradation, tissue targeting, and membrane permeability. This knowledge can be used to help design ocular delivery platforms for peptidomimetics, not only for the treatment of various retinal diseases, but also for the selection of potential peptidomimetic drug targets.

  View details for DOI 10.3390/biom11030339

  View details for PubMedID 33668179

• Structure-Aided Development of Small-Molecule Inhibitors of ENPP1, the Extracellular Phosphodiesterase of the Immunotransmitter cGAMP. Cell chemical biology Carozza, J. A., Brown, J. A., Bohnert, V., Fernandez, D., AlSaif, Y., Mardjuki, R. E., Smith, M., Li, L. 2020

  Abstract

  Cancer cells initiate an innate immune response by synthesizing and exporting the small-molecule immunotransmitter cGAMP, which activates the anti-cancer Stimulator of Interferon Genes (STING) pathway in the host. An extracellular enzyme, ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1), hydrolyzes cGAMP and negatively regulates this anti-cancer immune response. Small-molecule ENPP1 inhibitors are much needed as tools to study the basic biology of extracellular cGAMP and as investigational cancer immunotherapy drugs. Here, we surveyed structure-activity relationships around a series of cell-impermeable and thus extracellular-targeting phosphonate inhibitors of ENPP1. In addition, we solved the crystal structure of an exemplary phosphonate inhibitor to elucidate the interactions that drive potency. This study yielded several best-in-class inhibitors with Ki< 2nM and excellent physicochemical and pharmacokinetic properties. Finally, we demonstrate that an ENPP1 inhibitor delays tumor growth in a breast cancer mouse model. Together, we have developed ENPP1 inhibitors that are excellent tool compounds and potential therapeutics.

  View details for DOI 10.1016/j.chembiol.2020.07.007

  View details for PubMedID 32726585

• Recent Advances in the Chemical Synthesis and Evaluation of Anticancer Nucleoside Analogues. Molecules (Basel, Switzerland) Guinan, M., Benckendorff, C., Smith, M., Miller, G. J. 2020; 25 (9)

  Abstract

  Nucleoside analogues have proven to be highly successful chemotherapeutic agents in the treatment of a wide variety of cancers. Several such compounds, including gemcitabine and cytarabine, are the go-to option in first-line treatments. However, these materials do have limitations and the development of next generation compounds remains a topic of significant interest and necessity. Herein, we discuss recent advances in the chemical synthesis and biological evaluation of nucleoside analogues as potential anticancer agents. Focus is paid to 4'-heteroatom substitution of the furanose oxygen, 2'-, 3'-, 4'- and 5'-position ring modifications and the development of new prodrug strategies for these materials.

  View details for DOI 10.3390/molecules25092050

  View details for PubMedID 32354007

• Extracellular cGAMP is a cancer-cell-produced immunotransmitter involved in radiation-induced anticancer immunity NATURE CANCER Carozza, J. A., Bohnert, V., Nguyen, K. C., Skariah, G., Shaw, K. E., Brown, J. A., Rafat, M., von Eyben, R., Graves, E. E., Glenn, J. S., Smith, M., Li, L. 2020; 1 (2): 184-+

  View details for DOI 10.1038/s43018-020-0028-4

  View details for Web of Science ID 000608021200012

• Extracellular cGAMP is a cancer cell-produced immunotransmitter involved in radiation-induced anti-cancer immunity. Nature cancer Carozza, J. A., Böhnert, V., Nguyen, K. C., Skariah, G., Shaw, K. E., Brown, J. A., Rafat, M., von Eyben, R., Graves, E. E., Glenn, J. S., Smith, M., Li, L. 2020; 1 (2): 184-196

  Abstract

  2'3'-cyclic GMP-AMP (cGAMP) is an intracellular second messenger that is synthesized in response to cytosolic double-stranded DNA and activates the innate immune STING pathway. Our previous discovery of its extracellular hydrolase ENPP1 hinted at the existence of extracellular cGAMP. Here, we detected that cGAMP is continuously exported but then efficiently cleared by ENPP1, explaining why it has previously escaped detection. By developing potent, specific, and cell impermeable ENPP1 inhibitors, we found that cancer cells continuously export cGAMP in culture at steady state and at higher levels when treated with ionizing radiation (IR). In mouse tumors, depletion of extracellular cGAMP decreased tumor-associated immune cell infiltration and abolished the curative effect of IR. Boosting extracellular cGAMP with ENPP1 inhibitors synergized with IR to delay tumor growth. In conclusion, extracellular cGAMP is an anti-cancer immunotransmitter that could be harnessed to treat cancers with low immunogenicity.

  View details for DOI 10.1038/s43018-020-0028-4

  View details for PubMedID 33768207

  View details for PubMedCentralID PMC7990037

• PI4KIIIβ is a therapeutic target in chromosome 1q-amplified lung adenocarcinoma. Science translational medicine Tan, X. n., Banerjee, P. n., Pham, E. A., Rutaganira, F. U., Basu, K. n., Bota-Rabassedas, N. n., Guo, H. F., Grzeskowiak, C. L., Liu, X. n., Yu, J. n., Shi, L. n., Peng, D. H., Rodriguez, B. L., Zhang, J. n., Zheng, V. n., Duose, D. Y., Solis, L. M., Mino, B. n., Raso, M. G., Behrens, C. n., Wistuba, I. I., Scott, K. L., Smith, M. n., Nguyen, K. n., Lam, G. n., Choong, I. n., Mazumdar, A. n., Hill, J. L., Gibbons, D. L., Brown, P. H., Russell, W. K., Shokat, K. n., Creighton, C. J., Glenn, J. S., Kurie, J. M. 2020; 12 (527)

  Abstract

  Heightened secretion of protumorigenic effector proteins is a feature of malignant cells. Yet, the molecular underpinnings and therapeutic implications of this feature remain unclear. Here, we identify a chromosome 1q region that is frequently amplified in diverse cancer types and encodes multiple regulators of secretory vesicle biogenesis and trafficking, including the Golgi-dedicated enzyme phosphatidylinositol (PI)-4-kinase IIIβ (PI4KIIIβ). Molecular, biochemical, and cell biological studies show that PI4KIIIβ-derived PI-4-phosphate (PI4P) synthesis enhances secretion and accelerates lung adenocarcinoma progression by activating Golgi phosphoprotein 3 (GOLPH3)-dependent vesicular release from the Golgi. PI4KIIIβ-dependent secreted factors maintain 1q-amplified cancer cell survival and influence prometastatic processes in the tumor microenvironment. Disruption of this functional circuitry in 1q-amplified cancer cells with selective PI4KIIIβ antagonists induces apoptosis and suppresses tumor growth and metastasis. These results support a model in which chromosome 1q amplifications create a dependency on PI4KIIIβ-dependent secretion for cancer cell survival and tumor progression.

  View details for DOI 10.1126/scitranslmed.aax3772

  View details for PubMedID 31969487

• Enhancing the Antiviral Efficacy of RNA-Dependent RNA Polymerase Inhibition by Combination with Modulators of Pyrimidine Metabolism. Cell chemical biology Liu, Q. n., Gupta, A. n., Okesli-Armlovich, A. n., Qiao, W. n., Fischer, C. R., Smith, M. n., Carette, J. E., Bassik, M. C., Khosla, C. n. 2020

  Abstract

  Genome-wide analysis of the mode of action of GSK983, a potent antiviral agent, led to the identification of dihydroorotate dehydrogenase as its target along with the discovery that genetic knockdown of pyrimidine salvage sensitized cells to GSK983. Because GSK983 is an ineffective antiviral in the presence of physiological uridine concentrations, we explored combining GSK983 with pyrimidine salvage inhibitors. We synthesized and evaluated analogs of cyclopentenyl uracil (CPU), an inhibitor of uridine salvage. We found that CPU was converted into its triphosphate in cells. When combined with GSK983, CPU resulted in large drops in cellular UTP and CTP pools. Consequently, CPU-GSK983 suppressed dengue virus replication in the presence of physiological concentrations of uridine. In addition, the CPU-GSK983 combination markedly enhanced the effect of RNA-dependent RNA polymerase (RdRp) inhibition on viral infection. Our findings highlight a new host-targeting strategy for potentiating the antiviral activity of RdRp inhibitors.

  View details for DOI 10.1016/j.chembiol.2020.05.002

  View details for PubMedID 32442424

  View details for PubMedCentralID PMC7241336

• Generation of highly potent DYRK1A-dependent inducers of human beta-Cell replication via Multi-Dimensional compound optimization. Bioorganic & medicinal chemistry Allegretti, P. A., Horton, T. M., Abdolazimi, Y., Moeller, H. P., Yeh, B., Caffet, M., Michel, G., Smith, M., Annes, J. P. 2019: 115193

  Abstract

  Small molecule stimulation of beta-cell regeneration has emerged as a promising therapeutic strategy for diabetes. Although chemical inhibition of dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) is sufficient to enhance beta-cell replication, current lead compounds have inadequate cellular potency for in vivo application. Herein, we report the clinical stage anti-cancer kinase inhibitor OTS167 as a structurally novel, remarkably potent DYRK1A inhibitor and inducer of human beta-cell replication. Unfortunately, OTS167's target promiscuity and cytotoxicity curtails utility. To tailor kinase selectivity towards DYRK1A and reduce cytotoxicity we designed a library of fifty-one OTS167 derivatives based upon a modeled structure of the DYRK1A-OTS167 complex. Indeed, derivative characterization yielded several leads with exceptional DYRK1A inhibition and human beta-cell replication promoting potencies but substantially reduced cytotoxicity. These compounds are the most potent human beta-cell replication-promoting compounds yet described and exemplify the potential to purposefully leverage off-target activities of advanced stage compounds for a desired application.

  View details for DOI 10.1016/j.bmc.2019.115193

  View details for PubMedID 31757680

• ENPP1 antagonists in combination with radiation or checkpoint inhibitors demonstrate antitumor activity in syngeneic mice models of pancreatic adenocarcinoma, neuroblastoma, TNBC, and colon cancer Li, L., Smith, M., Chang, B. BMC. 2019

  View details for Web of Science ID 000496473200157

• 2 ' 3 '-cGAMP is an immunotransmitter produced by cancer cells and regulated by ENPP1 Carozza, J., Bohnert, V., Shaw, K., Khanh Nyugen, Skariah, G., Brown, J., Rafat, M., von Eyben, R., Graves, E., Glenn, J., Smith, M., Li, L. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061505479

• Zinc-Chelating Small Molecules Preferentially Accumulate and Function within Pancreatic beta Cells CELL CHEMICAL BIOLOGY Horton, T. M., Allegretti, P. A., Lee, S., Moeller, H. P., Smith, M., Annes, J. P. 2019; 26 (2): 213-+

  View details for DOI 10.1016/j.chembiol.2018.10.019

  View details for Web of Science ID 000460048700007

• SAR optimization studies on modified salicylamides as a potential treatment for acute myeloid leukemia through inhibition of the CREB pathway. Bioorganic & medicinal chemistry letters Chae, H. D., Cox, N. n., Capolicchio, S. n., Lee, J. W., Horikoshi, N. n., Kam, S. n., Ng, A. A., Edwards, J. n., Butler, T. L., Chan, J. n., Lee, Y. n., Potter, G. n., Capece, M. C., Liu, C. W., Wakatsuki, S. n., Smith, M. n., Sakamoto, K. M. 2019

  Abstract

  Disruption of cyclic adenosine monophosphate response element binding protein (CREB) provides a potential new strategy to address acute leukemia, a disease associated with poor prognosis, and for which conventional treatment options often carry a significant risk of morbidity and mortality. We describe the structure-activity relationships (SAR) for a series of XX-650-23 derived from naphthol AS-E phosphate that disrupts binding and activation of CREB by the CREB-binding protein (CBP). Through the development of this series, we identified several salicylamides that are potent inhibitors of acute leukemia cell viability through inhibition of CREB-CBP interaction. Among them, a biphenyl salicylamide, compound 71, was identified as a potent inhibitor of CREB-CBP interaction with improved physicochemical properties relative to previously described derivatives of naphthol AS-E phosphate.

  View details for DOI 10.1016/j.bmcl.2019.06.023

  View details for PubMedID 31253529

• CC-401 Promotes beta-Cell Replication via Pleiotropic Consequences of DYRK1A/B Inhibition ENDOCRINOLOGY Abdolazimi, Y., Zhao, Z., Lee, S., Xu, H., Allegretti, P., Horton, T. M., Yeh, B., Moeller, H. P., Nichols, R. J., McCutcheon, D., Shalizi, A., Smith, M., Armstrong, N. A., Annes, J. P. 2018; 159 (9): 3143–57

  View details for DOI 10.1210/en.2018-00083

  View details for Web of Science ID 000446426000002

• A Gut Commensal-Produced Metabolite Mediates Colonization Resistance to Salmonella Infection CELL HOST & MICROBE Jacobson, A., Lam, L., Rajendram, M., Tamburini, F., Honeycutt, J., Trung Pham, Van Treuren, W., Pruss, K., Stabler, S., Lugo, K., Bouley, D. M., Vilches-Moure, J. G., Smith, M., Sonnenburg, J. L., Bhatt, A. S., Huang, K., Monack, D. 2018; 24 (2): 296-+

  View details for DOI 10.1016/j.chom.2018.07.002

  View details for Web of Science ID 000441083900016

• A Gut Commensal-Produced Metabolite Mediates Colonization Resistance to Salmonella Infection. Cell host & microbe Jacobson, A., Lam, L., Rajendram, M., Tamburini, F., Honeycutt, J., Pham, T., Van Treuren, W., Pruss, K., Stabler, S. R., Lugo, K., Bouley, D. M., Vilches-Moure, J. G., Smith, M., Sonnenburg, J. L., Bhatt, A. S., Huang, K. C., Monack, D. 2018

  Abstract

  The intestinal microbiota provides colonization resistance against pathogens, limiting pathogen expansion and transmission. These microbiota-mediated mechanisms were previously identified by observing loss of colonization resistance after antibiotic treatment or dietary changes, which severely disrupt microbiota communities. We identify a microbiota-mediated mechanism of colonization resistance against Salmonella enterica serovar Typhimurium (S. Typhimurium) by comparing high-complexity commensal communities with different levels of colonization resistance. Using inbred mouse strains with different infection dynamics and S. Typhimurium intestinal burdens, we demonstrate that Bacteroides species mediate colonization resistance against S. Typhimurium by producing the short-chain fatty acid propionate. Propionate directly inhibits pathogen growth invitro by disrupting intracellular pH homeostasis, and chemically increasing intestinal propionate levels protects mice from S.Typhimurium. In addition, administering susceptible mice Bacteroides, but not a propionate-production mutant, confers resistance to S. Typhimurium. This work provides mechanistic understanding into the role of individualized microbial communities in host-to-host variability of pathogen transmission.

  View details for PubMedID 30057174

• Niclosamide suppresses acute myeloid leukemia cell proliferation through inhibition of CREB-dependent signaling pathways ONCOTARGET Chae, H., Cox, N., Dahl, G. V., Lacayo, N. J., Davis, K. L., Capolicchio, S., Smith, M., Sakamoto, K. M. 2018; 9 (4): 4301–17

  Abstract

  CREB (cAMP Response Element Binding protein) is a transcription factor that is overexpressed in primary acute myeloid leukemia (AML) cells and associated with a decreased event-free survival and increased risk of relapse. We recently reported a small molecule inhibitor of CREB, XX-650-23, which inhibits CREB activity in AML cells. Structure-activity relationship analysis for chemical compounds with structures similar to XX-650-23 led to the identification of the anthelminthic drug niclosamide as a potent anti-leukemic agent that suppresses cell viability of AML cell lines and primary AML cells without a significant decrease in colony forming activity of normal bone marrow cells. Niclosamide significantly inhibited CREB function and CREB-mediated gene expression in cells, leading to apoptosis and G1/S cell cycle arrest with reduced phosphorylated CREB levels. CREB knockdown protected cells from niclosamide treatment-mediated cytotoxic effects. Furthermore, treatment with a combination of niclosamide and CREB inhibitor XX-650-23 showed an additive anti-proliferative effect, consistent with the hypothesis that niclosamide and XX-650-23 regulate the same targets or pathways to inhibit proliferation and survival of AML cells. Niclosamide significantly inhibited the progression of disease in AML patient-derived xenograft (PDX) mice, and prolonged survival of PDX mice. Niclosamide also showed synergistic effects with chemotherapy drugs to inhibit AML cell proliferation. While chemotherapy antagonized the cytotoxic potential of niclosamide, pretreatment with niclosamide sensitized cells to chemotherapeutic drugs, cytarabine, daunorubicin, and vincristine. Therefore, our results demonstrate niclosamide as a potential drug to treat AML by inducing apoptosis and cell cycle arrest through inhibition of CREB-dependent pathways in AML cells.

  View details for PubMedID 29435104

• CC-401 Promotes β-Cell Replication via Pleiotropic Consequences of DYRK1A/B Inhibition. Endocrinology Abdolazimi, Y. n., Lee, S. n., Xu, H. n., Allegretti, P. n., Horton, T. M., Yeh, B. n., Moeller, H. P., Nichols, R. J., McCutcheon, D. n., Shalizi, A. n., Smith, M. n., Armstrong, N. A., Annes, J. P. 2018

  Abstract

  Pharmacologic expansion of endogenous β-cells is a promising therapeutic strategy for diabetes. To elucidate the molecular pathways that control β-cell growth we screened ∼2,400 bioactive compounds for rat β-cell replication-modulating activity. Numerous hit compounds impaired or promoted rat β-cell replication, including CC-401, an advanced clinical candidate previously characterized as a c-Jun N-terminal kinase (JNK) inhibitor. Surprisingly, CC-401 induced rodent (in vitro and in vivo) and human (in vitro) β-cell replication via dual specificity tyrosine-phosphorylation-regulated kinases (DYRK1A/B) inhibition. In contrast to rat β-cells, which were broadly growth responsive to compound treatment, human β-cell replication was only consistently induced by DYRK1A/B inhibitors. This effect was enhanced by simultaneous glycogen synthase kinase-3β (GSK-3β) or transforming growth factor-β (ALK5/TGF-β) inhibition. Prior work emphasized DYRK1A/B inhibition-dependent activation of nuclear factor of activated T-cells (NFAT) as the primary mechanism of human β-cell replication induction. However, inhibition of NFAT activity had limited impact on CC-401-induced β-cell replication. Consequently, we investigated additional effects of CC-401-dependent DYRK1A/B inhibition. Indeed, CC-401 inhibited DYRK1A-dependent phosphorylation/stabilization of the β-cell replication-inhibitor p27Kip1. Additionally, CC-401 increased expression of numerous replication-promoting genes normally suppressed by the dimerization partner, RB-like, E2F and multi-vulval class B (DREAM) complex, which depends upon DYRK1A/B activity for integrity, including MYBL2 and FOXM1. In summary, we present a compendium of compounds as a valuable resource for manipulating the signaling pathways that control β-cell replication and leverage a novel DYRK1A/B inhibitor (CC-401) to expand our understanding of the molecular pathways that control β-cell growth.

  View details for PubMedID 29514186

• Zinc-Chelating Small Molecules Preferentially Accumulate and Function within Pancreatic β Cells. Cell chemical biology Horton, T. M., Allegretti, P. A., Lee, S. n., Moeller, H. P., Smith, M. n., Annes, J. P. 2018

  Abstract

  Diabetes is a hyperglycemic condition characterized by pancreatic β-cell dysfunction and depletion. Whereas methods for monitoring β-cell function in vivo exist, methods to deliver therapeutics to β cells are lacking. We leveraged the rare ability of β cells to concentrate zinc to preferentially trap zinc-binding molecules within β cells, resulting in β-cell-targeted compound delivery. We determined that zinc-rich β cells and islets preferentially accumulated TSQ (6-methoxy-8-p-toluenesulfonamido-quinoline) in a zinc-dependent manner compared with exocrine pancreas. Next, we asked whether appending a zinc-chelating moiety onto a β-cell replication-inducing compound was sufficient to confer preferential β-cell accumulation and activity. Indeed, the hybrid compound preferentially accumulated within rodent and human islets in a zinc-dependent manner and increased the selectivity of replication-promoting activity toward β cells. These data resolve the fundamental question of whether intracellular accumulation of zinc-chelating compounds is influenced by zinc content. Furthermore, application of this principle yielded a proof-of-concept method for β-cell-targeted drug delivery and bioactivity.

  View details for PubMedID 30527998

• The Salicylamide Derivative, Niclosamide, Inhibits CREB Function in Acute Myeloid Leukemia Cells In Vitro and In Vivo Chae, H., Cox, N., Zhang, X., Lee, J., Morgens, D., Bassik, M. C., Smith, M., Sakamoto, K. M. AMER SOC HEMATOLOGY. 2016

  View details for DOI 10.1182/blood.V128.22.1647.1647

  View details for Web of Science ID 000394452305078

• Integrin-Targeting Knottin Peptide-Drug Conjugates Are Potent Inhibitors of Tumor Cell Proliferation. Angewandte Chemie (International ed. in English) Cox, N., Kintzing, J. R., Smith, M., Grant, G. A., Cochran, J. R. 2016; 55 (34): 9894-9897

  Abstract

  Antibody-drug conjugates (ADCs) offer increased efficacy and reduced toxicity compared to systemic chemotherapy. Less attention has been paid to peptide-drug delivery, which has the potential for increased tumor penetration and facile synthesis. We report a knottin peptide-drug conjugate (KDC) and demonstrate that it can selectively deliver gemcitabine to malignant cells expressing tumor-associated integrins. This KDC binds to tumor cells with low-nanomolar affinity, is internalized by an integrin-mediated process, releases its payload intracellularly, and is a highly potent inhibitor of brain, breast, ovarian, and pancreatic cancer cell lines. Notably, these features enable this KDC to bypass a gemcitabine-resistance mechanism found in pancreatic cancer cells. This work expands the therapeutic relevance of knottin peptides to include targeted drug delivery, and further motivates efforts to expand the drug-conjugate toolkit to include non-antibody protein scaffolds.

  View details for DOI 10.1002/anie.201603488

  View details for PubMedID 27304709

• Parallel shRNA and CRISPR-Cas9 screens enable antiviral drug target identification NATURE CHEMICAL BIOLOGY Deans, R. M., Morgens, D. W., Okesli, A., Pillay, S., Horlbeck, M. A., Kampmann, M., Gilbert, L. A., Li, A., Mateo, R., Smith, M., Glenn, J. S., Carette, J. E., Khosla, C., Bassik, M. C. 2016; 12 (5): 361-?

  Abstract

  Broad-spectrum antiviral drugs targeting host processes could potentially treat a wide range of viruses while reducing the likelihood of emergent resistance. Despite great promise as therapeutics, such drugs remain largely elusive. Here we used parallel genome-wide high-coverage short hairpin RNA (shRNA) and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screens to identify the cellular target and mechanism of action of GSK983, a potent broad-spectrum antiviral with unexplained cytotoxicity. We found that GSK983 blocked cell proliferation and dengue virus replication by inhibiting the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH). Guided by mechanistic insights from both genomic screens, we found that exogenous deoxycytidine markedly reduced GSK983 cytotoxicity but not antiviral activity, providing an attractive new approach to improve the therapeutic window of DHODH inhibitors against RNA viruses. Our results highlight the distinct advantages and limitations of each screening method for identifying drug targets, and demonstrate the utility of parallel knockdown and knockout screens for comprehensive probing of drug activity.

  View details for DOI 10.1038/NCHEMBIO.2050

  View details for PubMedID 27018887

• Engineered knottin peptide-drug conjugates selectively deliver small molecules to brain tumors in mice Cox, N., Kintzing, J., Currier, N., Ackerman, S., DePorter, S., Smith, M., Grant, G., Cochran, J. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431903801359

• Small molecule screen for inhibitors of expression from canonical CREB response element-containing promoters. Oncotarget Mitton, B., Hsu, K., Dutta, R., Tiu, B. C., Cox, N., McLure, K. G., Chae, H., Smith, M., Eklund, E. A., Solow-Cordero, D. E., Sakamoto, K. M. 2016; 7 (8): 8653-8662

  Abstract

  The transcription factor CREB (cAMP Response Element Binding Protein) is an important determinant in the growth of Acute Myeloid Leukemia (AML) cells. CREB overexpression increases AML cell growth by driving the expression of key regulators of apoptosis and the cell cycle. Conversely, CREB knockdown inhibits proliferation and survival of AML cells but not normal hematopoietic cells. Thus, CREB represents a promising drug target for the treatment of AML, which carries a poor prognosis. In this study, we performed a high-throughput small molecule screen to identify compounds that disrupt CREB function in AML cells. We screened ~114,000 candidate compounds from Stanford University's small molecule library, and identified 5 molecules that inhibit CREB function at micromolar concentrations, but are non-toxic to normal hematopoietic cells. This study suggests that targeting CREB function using small molecules could provide alternative approaches to treat AML.

  View details for DOI 10.18632/oncotarget.7085

  View details for PubMedID 26840025

  View details for PubMedCentralID PMC4890994