Systems Biology at Harvard Medical School
Transcription
Systems Biology at Harvard Medical School
Systems Biology at Harvard Medical School The Department of Systems Biology was founded in 2003 in response to a growing realization that complex diseases—such as rheumatoid arthritis, osteoporosis, cancer, and schizophrenia—result from complex combinations of factors that are challenging to address with the current tools of biomedical science. This complexity is forcing biologists to turn to the intellectual tools of other disciplines, such as physics, mathematics, and computational science. Harvard Medical School's bold step was to create a full Department of Systems Biology—the first in the world—within the intense biomedical research environment of the Longwood Medical Area. Thanks to initial key hires of outstanding theoreticians with a genuine commitment to biomedical research, the department has become a magnet for the very best young researchers in this area, and the related field of synthetic biology. The department's alumni, students and post-doctoral fellows who trained in the department, are now leading the development of systems biology and synthetic biology across the globe. SELECTED STATISTICS Growth of the Department The number of members of the Department of Systems Biology grew from 73 to 336 between 2004 and 2014. Scientific Contributions The department has published 1,508 papers over the last 10 years, using mathematical and computational approaches to offer novel insights into cancer, infectious disease, aging, human physiology, genetic diseases, and vertebrate development. Key contributions include: o Computer-enabled methods for measuring cell growth, aging, gene expression, and cell movement in model organisms; o A new perspective on how antibiotic resistance evolves, and how to slow or reverse the spread of resistance; o Profound revisions to the textbook models of spinal cord development and the behavior of adult stem cells; o New models of the behavior of signaling pathways in cancer that help predict and explain how these pathways behave; o Dramatic progress in engineering biological materials to make precise shapes, engineering improved carbon fixation and making useful molecules such as hydrogen, sugar, and other products; o New theoretical and experimental approaches to the problem of variation, or “noise”, in biology. Noise is important in clinical problems, such as “fractional kill” in cancer therapy and the persistence of bacterial infections after antibiotic treatment; o A new level of understanding of the mitochondrion, the powerhouse of the cell, and its role in disease; o Novel ways to detect diseases, such as anemia, colon cancer, kidney injury, diabetes, and tuberculosis, as well as engineered cells that record antibiotic treatments; o Methods for predicting protein structure from DNA sequence information, solving a decades-old problem of great importance; o Ways to understand drug action at a new level, contributing to the founding of the Harvard Program in Therapeutic Science (HiTS). A Pioneering Interdisciplinary Effort All laboratories in the department include an interdisciplinary mix of biologists, mathematicians, physicists, computational scientists, and engineers. Because of the interdisciplinary training we offer, many individual scientists are able to span multiple disciplines in their own research. Department faculty and trainees come from many different backgrounds, but are all entirely committed to biomedical research. This commitment has led to an unusual degree of focus on real medical problems, compared to other systems biology efforts. Global leadership The PhD Program in systems biology is acknowledged to be one of the very best programs of its kind in the country. It is highly competitive (average ~7% acceptance rate) and about two-thirds of admitted U.S. students win national fellowship awards. Ninety-two students have entered the program so far, 24 of whom have graduated. An average student graduating from the program has published 3.5 papers, two of which s/he is first author Post-docs and students from the department are now leading their own labs in many institutions across the world, as evidenced by the maps on the following page. More than 100 department alumni are now faculty across the globe… …with more than 70 in the United States Systems Biology Accomplishments Table of Contents A brief summary of the accomplishments of the Department of Systems Biology in the last decade (selected from 1508 publications) Computer-enabled methods for probing cell growth, aging, gene expression, cell division, and cancer.............................................................................................page 2 A new perspective on how antibiotic resistance evolves, and how to slow or reverse the spread of resistance................................................................................page 3 Profound revisions to the textbook models of spinal chord development and the behavior of adult stem cells.................................................................................page 4 New models of signaling pathways in cancer that help predict and explain how these pathways behave.............................................................................................page 6 Dramatic progress in engineering biological materials and cells to provide useful products..........................................................................................................page 7 New theoretical and experimental approaches to the problem of variation, or "noise" in biology...................................................................................................page 8 A new level of understanding of the mitochondrion, the powerhouse of the cell. ..........................................................................................................................page 10 New ways to detect diseases such as anemia, colon cancer, kidney injury, diabetes and tuberculosis, as well as engineered cells that record antibiotic treatments...............................................................................................................page 11 Methods for predicting protein structure from DNA sequence information, solving a decades-old problem of great importance...............................................page 12 A world-leading effort in applying new theoretical principles to biological systems....................................................................................................................page 13 Ways to understand drug action at a new level, contributing to the founding of Harvard Medical School's Therapeutics Initiative................................................page 14 1 Computer-enabled methods for probing cell growth, aging, gene expression, cell division, and cancer The power of mathematical and computational analysis has transformed much of daily life, and is now transforming biological experimentation. Our faculty have been pioneers in several areas. Publications include: Kafri R, Levy J, Ginzberg MB, Oh S, Lahav G, Kirschner MW. Dynamics extracted from fixed cells reveal feedback linking cell growth to cell cycle. Nature. 2013 Feb 28;494(7438):480-3. Stroustrup N, Ulmschneider BE, Nash ZM, López-Moyado IF, Apfeld J, Fontana W. The Caenorhabditis elegans Lifespan Machine. Nat Methods. 2013 Jul;10(7):665-70. Wunderlich Z, Bragdon MD, Eckenrode KB, Lydiard-Martin T, Pearl-Waserman S, DePace AH. Dissecting sources of quantitative gene expression pattern divergence between Drosophila species. Mol Syst Biol. 2012;8:604. Zidovska A, Weitz DA, Mitchison TJ. Micron-scale coherence in interphase chromatin dynamics. Proc Natl Acad Sci U S A. 2013 Sep 24;110(39):15555-60. Jain M, Nilsson R, Sharma S, Madhusudhan N, Kitami T, Souza AL, Kafri R, Kirschner MW, Clish CB, Mootha VK. Metabolite profiling identifies a key role for glycine in rapid cancer cell proliferation. Science. 2012 May 25;336(6084):1040-4. Hao N, Budnik BA, Gunawardena J, O'Shea EK. Tunable signal processing through modular control of transcription factor translocation. Science. 2013 Jan 25;339(6118):460-4. Choi PJ, Mitchison TJ. Imaging burst kinetics and spatial coordination during serial killing by single natural killer cells. Proc Natl Acad Sci U S A. 2013 Apr 16;110(16):6488-93. 2 A new perspective on how antibiotic resistance evolves Antibiotic resistance is a growing, and extremely worrying, problem. A highly influential set of publications from the Kishony lab shows that carefully chosen combinations of drugs can slow, and even reverse, the evolution of resistance. Publications include: Toprak E, Veres A, Michel JB, Chait R, Hartl DL, Kishony R. Evolutionary paths to antibiotic resistance under dynamically sustained drug selection. Nat Genet. 2011 Dec 18;44(1):101-5. Palmer AC, Angelino E, Kishony R. Chemical decay of an antibiotic inverts selection for resistance. Nat Chem Biol. 2010 Mar;6(3):244. Bollenbach T, Quan S, Chait R, Kishony R. Nonoptimal microbial response to antibiotics underlies suppressive drug interactions. Cell. 2009 Nov 13;139(4):707-18. Chait R, Craney A, Kishony R. Antibiotic interactions that select against resistance. Nature. 2007 Apr 5;446(7136):668-71. Bollenbach T, Quan S, Chait R, Kishony R. Nonoptimal microbial response to antibiotics underlies suppressive drug interactions. Cell. 2009 Nov 13;139(4):707-18. Michel JB, Yeh PJ, Chait R, Moellering RC Jr, Kishony R. Drug interactions modulate the potential for evolution of resistance. Proc Natl Acad Sci U S A. 2008 Sep 30;105(39):14918-23 Hegreness M, Shoresh N, Damian D, Hartl D, Kishony R. Accelerated evolution of resistance in multidrug environments. Proc Natl Acad Sci U S A. 2008 Sep 16;105(37):13977-81. Chait R, Craney A, Kishony R. Antibiotic interactions that select against resistance. Nature. 2007 Apr 5;446(7136):668-71 3 Profound revisions to the textbook models of the behavior of adult stem cells, and the development of the spinal cord Adult stem cells reside in individual tissues and are responsible for tissue regeneration and repair. Until recently, our understanding has been that stem cells always divide asymmetrically, producing one cell that retains "stem-ness" and another that is used to regenerate the tissue. New research from Allon Klein now shows that these cells instead maintain themselves probabilistically: stem cell divisions can produce two stem cells, one stem cell and a regenerating cell, or two regenerating cells. New model Old model Publications include: Lim X, Tan SH, Koh WL, Chau RM, Yan KS, Kuo CJ, van Amerongen R, Klein AM, Nusse R. Interfollicular epidermal stem cells self-renew via autocrine Wnt signaling. Science. 2013 Dec 6;342(6163):1226-30. Doupé DP, Alcolea MP, Roshan A, Zhang G, Klein AM, Simons BD, Jones PH. A single progenitor population switches behavior to maintain and repair esophageal epithelium. Science. 2012 Aug 31;337(6098):1091-3. Klein AM, Simons BD. Universal patterns of stem cell fate in cycling adult tissues. Development. 2011 Aug;138(15):3103-11. Klein AM, Nikolaidou-Neokosmidou V, Doupé DP, Jones PH, Simons BD. Patterning as a signature of human epidermal stem cell regulation. J R Soc Interface. 2011 Dec 7;8(65):1815-24. 4 As the spinal chord develops in vertebrate embryos, neural precursors are instructed to develop into different types of neurons (e.g.motor neurons that control muscles and sensory neurons that respond to pain, etc.) that must arrange themselves in different locations. Until this year, our understanding has been that the neural precursors decide what kind of neuron to become based on their position in the developing spinal cord. New work from the Megason lab now shows that instead precursors decide what to become first, then move to the appropriate position. Old model New model Key publication: Xiong F, Tentner AR, Huang P, Gelas A, Mosaliganti KR, Souhait L, Rannou N, Swinburne IA, Obholzer ND, Cowgill PD, Schier AF, Megason SG. Specified neural progenitors sort to form sharp domains after noisy Shh signaling. Cell. 2013 Apr 25;153(3):550-61. 5 New models of signaling pathways in cancer that help predict and explain how these pathways behave Cancer is one of the best-studied situations in which multiple mutations interact to create a disease state. Systems biology approaches aim to understand and predict how molecular changes cause changes in the behavior of the pathway. The Kirschner, Lahav and Sorger laboratories are especially active in this area. Hernández AR, Klein AM, Kirschner MW. Kinetic responses of β-catenin specify the sites of Wnt control. Science. 2012 Dec 7;338(6112):1337-40 Gaglia G, Guan Y, Shah JV, Lahav G. Activation and control of p53 tetramerization in individual living cells. Proc Natl Acad Sci U S A. 2013 Sep 17;110(38):15497-501. Purvis JE, Karhohs KW, Mock C, Batchelor E, Loewer A, Lahav G. p53 dynamics control cell fate. Science. 2012 Jun 15;336(6087):1440-4. Gaudet S, Spencer SL, Chen WW, Sorger PK. Exploring the contextual sensitivity of factors that determine cell-to-cell variability in receptor-mediated apoptosis. PLoS Comput Biol. 2012;8(4):e1002482. Aldridge BB, Gaudet S, Lauffenburger DA, Sorger PK. Lyapunov exponents and phase diagrams reveal multi-factorial control over TRAIL-induced apoptosis. Mol Syst Biol. 2011 Nov 22;7:553. Dasgupta T, Croll DH, Owen JA, Vander Heiden MG, Locasale JW, Alon U, Cantley LC, Gunawardena J. A fundamental trade off in covalent switching and its circumvention by enzyme bifunctionality in glucose homeostasis. J Biol Chem. 2014 Mar 14 (in press). 6 Dramatic progress in engineering biological materials and cells to provide useful products Biology is an extraordinarily powerful technology. Biological systems have produced all of the fossil fuels we use today, as well as producing building materials and food from air, a handful of minerals, and water. One reason for the power of biological systems is that they can control events on the molecular level through enzymes and molecular machines. The Silver and Yin labs are leaders in efforts to harness these technologies for new uses, by building precise structures out of DNA or engineering cells to produce biofuels such as hydrogen, or other useful materials. Publications include: Myhrvold C, Dai M, Silver PA, Yin P. Isothermal self-assembly of complex DNA structures under diverse and biocompatible conditions. Nano Lett. 2013 Sep 11;13(9):4242-8. Torella JP, Ford TJ, Kim SN, Chen AM, Way JC, Silver PA. Tailored fatty acid synthesis via dynamic control of fatty acid elongation. Proc Natl Acad Sci U S A. 2013 Jul 9;110(28):11290-5. Delebecque CJ, Silver PA, Lindner AB. Designing and using RNA scaffolds to assemble proteins in vivo. Nat Protoc. 2012 Oct;7(10):1797-807 Iinuma R, Ke Y, Jungmann R, Schlichthaerle T, Woehrstein JB, Yin P. Polyhedra Self-Assembled from DNA Tripods and Characterized with 3D DNA-PAINT. Science. 2014 Mar 13. Ke Y, Ong LL, Shih WM, Yin P. Three-dimensional structures self-assembled from DNA bricks. Science. 2012 Nov 30;338(6111):1177-83 Lin C, Jungmann R, Leifer AM, Li C, Levner D, Church GM, Shih WM, Yin P. Submicrometre geometrically encoded fluorescent barcodes self-assembled from DNA. Nat Chem. 2012 Oct;4(10):832-9. 7 New theoretical and experimental approaches to the problem of variation, or "noise" in biology Variation is the heart of biology. It drives evolution — natural selection selects the fittest among variants — and allows organisms to survive challenges and change. Unlike a machine, a biological system does not stop working when a change is made. Instead, it adapts: it makes use of its ability to vary to compensate for the change. Effects traceable to variation and adaptability are present in all diseases, notably cancer, infectious disease, and genetic predisposition Variation has been relatively little studied in biology until the last 10 years. It is difficult to study because the effects of variation can be deeply counter-intuitive. Our faculty have been leaders in this field. Examples of key contributions include: • New theory showing how the behavior of a cell is affected by variation in the molecules that make up the cell. Johan Paulsson is the acknowledged world leader in developing sound mathematical foundations for the study of the causes and consequences of variation. Publications include: Hilfinger A, Chen M, Paulsson J. Using temporal correlations and full distributions to separate intrinsic and extrinsic fluctuations in biological systems. Phys Rev Lett. 2012 Dec 14;109(24):248104. Huh D, Paulsson J. Random partitioning of molecules at cell division. Proc Natl Acad Sci U S A. 2011 Sep 6;108(36):15004-9. Hilfinger A, Paulsson J. Separating intrinsic from extrinsic fluctuations in dynamic biological systems. Proc Natl Acad Sci U S A. 2011 Jul 19;108(29):12167-72. Huh D, Paulsson J. Non-genetic heterogeneity from stochastic partitioning at cell division. Nat Genet. 2011 Feb;43(2):95-100. Pedraza JM, Paulsson J. Effects of molecular memory and bursting on fluctuations in gene expression. Science. 2008 Jan 18;319(5861):339-43. • New experiments showing the role of variation in bacterial biofilms — a growing medical threat — antibiotic resistance, cancer, drug responsiveness, and the use of drug combinations. The Paulsson, Sorger and Kishony labs are leaders in these areas. Publications include: Norman TM, Lord ND, Paulsson J, Losick R. Memory and modularity in cell-fate decision making. Nature. 2013 Nov 28;503(7477):481-6. 8 Lau BT, Malkus P, Paulsson J. New quantitative methods for measuring plasmid loss rates reveal unexpected stability. Plasmid. 2013 Nov;70(3):353-61. Fallahi-Sichani M, Honarnejad S, Heiser LM, Gray JW, Sorger PK. Metrics other than potency reveal systematic variation in responses to cancer drugs. Nat Chem Biol. 2013 Nov;9(11):708-14. Flusberg DA, Sorger PK. Modulating cell-to-cell variability and sensitivity to death ligands by codrugging. Phys Biol. 2013 Jun;10(3):035002. Spencer SL, Gaudet S, Albeck JG, Burke JM, Sorger PK. Non-genetic origins of cell-to-cell variability in TRAIL-induced apoptosis. Nature. 2009 May 21;459 Lieberman TD, Flett KB, Yelin I, Martin TR, McAdam AJ, Priebe GP, Kishony R. Genetic variation of a bacterial pathogen within individuals with cystic fibrosis provides a record of selective pressures. Nat Genet. 2014 Jan;46(1):82-7 Toprak E, Veres A, Michel JB, Chait R, Hartl DL, Kishony R. Evolutionary paths to antibiotic resistance under dynamically sustained drug selection. Nat Genet. 2011 Dec 18;44(1):101-5. Lieberman TD, Michel JB, Aingaran M, Potter-Bynoe G, Roux D, Davis MR Jr, Skurnik D, Leiby N, LiPuma JJ, Goldberg JB, McAdam AJ, Priebe GP, Kishony R. Parallel bacterial evolution within multiple patients identifies candidate pathogenicity genes. Nat Genet. 2011 Nov 13;43(12):1275-80. 9 A new level of understanding of the mitochondrion, the powerhouse of the cell The mitochondrion is responsible for generating chemical energy for the cell. It is a special compartment within the cell with an unusual chemical environment, constructed from a double membrane and a large set of special proteins. Mutations in mitochondrial proteins cause a wide range of genetic diseases that have acute effects in children but also are thought to play a role in cancer, diabetes, and neurodegenerative disease. The Mootha lab is a world leader in using computational techniques to identify mitochondrial proteins and thereby identify the genetic mutations responsible for disease. Publications include: Calvo SE, Compton AG, Hershman SG, Lim SC, Lieber DS, Tucker EJ, Laskowski A, Garone C, Liu S, Jaffe DB, Christodoulou J, Fletcher JM, Bruno DL, Goldblatt J, Dimauro S, Thorburn DR, Mootha VK. Molecular diagnosis of infantile mitochondrial disease with targeted next-generation sequencing. Sci Transl Med. 2012 Jan 25;4(118):118ra10. Ronchi D, Garone C, Bordoni A, Gutierrez Rios P, Calvo SE, Ripolone M, Ranieri M, Rizzuti M, Villa L, Magri F, Corti S, Bresolin N, Mootha VK, Moggio M, DiMauro S, Comi GP, Sciacco M. Nextgeneration sequencing reveals DGUOK mutations in adult patients with mitochondrial DNA multiple deletions. Brain. 2012 Nov;135(Pt 11):3404-15. Tucker EJ, Hershman SG, Köhrer C, Belcher-Timme CA, Patel J, Goldberger OA, Christodoulou J, Silberstein JM, McKenzie M, Ryan MT, Compton AG, Jaffe JD, Carr SA, Calvo SE, RajBhandary UL, Thorburn DR, Mootha VK. Mutations in MTFMT underlie a human disorder of formylation causing impaired mitochondrial translation. Cell Metab. 2011 Sep 7;14(3):428-34. Garone C, Rubio JC, Calvo SE, Naini A, Tanji K, Dimauro S, Mootha VK, Hirano M. MPV17 Mutations Causing Adult-Onset Multisystemic Disorder With Multiple Mitochondrial DNA Deletions. Arch Neurol. 2012 Dec;69(12):1648-51. doi: 10.1001/archneurol.2012.405. Sancak Y, Markhard AL, Kitami T, Kovács-Bogdán E, Kamer KJ, Udeshi ND, Carr SA, Chaudhuri D, Clapham DE, Li AA, Calvo SE, Goldberger O, Mootha VK. EMRE is an essential component of the mitochondrial calcium uniporter complex. Science. 2013 Dec 13;342(6164):1379-82. Baughman JM, Perocchi F, Girgis HS, Plovanich M, Belcher-Timme CA, Sancak Y, Bao XR, Strittmatter L, Goldberger O, Bogorad RL, Koteliansky V, Mootha VK. Integrative genomics identifies MCU as an essential component of the mitochondrial calcium uniporter. Nature. 2011 Jun 19;476(7360):341-5. 10 Methods for predicting protein structure from DNA sequence information, solving a decades-old problem of great importance The so-called "protein folding problem" has challenged researchers for decades. In principle the sequence of a protein includes all of the information required to predict its structure. Yet, because of the promiscuity of interactions between the building blocks of the protein, the amino acids, the number of possible structures that could result from a single sequence is so large that it has been impossible to search through them to find the correct one. The advent of large-scale genomic sequencing has provided many clues to protein sequence, by giving us sets of sequences of families of proteins in different organisms, that presumably all fold in the same way. Even so, it has been extremely challenging to correct structures from incorrect ones. The Marks lab has used a new approach based on global statistical methods drawn from physics to solve this problem for medium-sized proteins in large families. This is a huge step forward in what has been a very intractable problem. It has been particularly important in the study of proteins that are hard to study by other means. Key publications: Hopf TA, Colwell LJ, Sheridan R, Rost B, Sander C, Marks DS. Three-dimensional structures of membrane proteins from genomic sequencing. Cell. 2012 Jun 22;149(7):1607-21 Marks DS, Colwell LJ, Sheridan R, Hopf TA, Pagnani A, Zecchina R, Sander C. Protein 3D structure computed from evolutionary sequence variation. PLoS One. 2011;6(12):e28766. Morcos F, Pagnani A, Lunt B, Bertolino A, Marks DS, Sander C, Zecchina R, Onuchic JN, Hwa T, Weigt M. Direct-coupling analysis of residue coevolution captures native contacts across many protein families. Proc Natl Acad Sci U S A. 2011 Dec 6;108(49):E1293-301. 11 New ways to detect diseases such as anemia, colon cancer, kidney injury, diabetes and tuberculosis, as well as engineered cells that record antibiotic treatments Synthetic biology, imaging and computational analysis have together made it possible to create new biomarkers of disease that make disease diagnoses faster and more accurate. Examples include: Kotula JW, Kerns SJ, Shaket LA, Siraj L, Collins JJ, Way JC, Silver PA. Programmable bacteria detect and record an environmental signal in the mammalian gut. Proc Natl Acad Sci U S A. 2014 (in press) Liong M, Hoang AN, Chung J, Gural N, Ford CB, Min C, Shah RR, Ahmad R, Fernandez-Suarez M, Fortune SM, Toner M, Lee H, Weissleder R. Magnetic barcode assay for genetic detection of pathogens. Nat Commun. 2013;4:1752 Wood DK, Soriano A, Mahadevan L, Higgins JM, Bhatia SN. A biophysical indicator of vaso-occlusive risk in sickle cell disease. Sci Transl Med. 2012 Feb 29;4(123):123ra26. Higgins JM, Mahadevan L. Physiological and pathological population dynamics of circulating human red blood cells. Proc Natl Acad Sci U S A. 2010 Nov 23;107(47):20587-92. Miller MA, Askevold B, Yang KS, Kohler RH, Weissleder R. Platinum Compounds for HighResolution In Vivo Cancer Imaging. ChemMedChem. 2014 Feb 6. doi: 10.1002/cmdc.201300502. Peterson VM, Castro CM, Chung J, Miller NC, Ullal AV, Castano MD, Penson RT, Lee H, Birrer MJ, Weissleder R. Ascites analysis by a microfluidic chip allows tumor-cell profiling. Proc Natl Acad Sci U S A. 2013 Dec 17;110(51):E4978-86 Yang L, Besschetnova TY, Brooks CR, Shah JV, Bonventre JV. Epithelial cell cycle arrest in G2/M mediates kidney fibrosis after injury. Nat Med. 2010 May;16(5):535-43 Shaham O, Wei R, Wang TJ, Ricciardi C, Lewis GD, Vasan RS, Carr SA, Thadhani R, Gerszten RE, Mootha VK. Metabolic profiling of the human response to a glucose challenge reveals distinct axes of insulin sensitivity. Mol Syst Biol. 2008;4:214. 12 A world-leading effort in applying new theoretical principles to biological systems Our Department is recognized as a major nexus for theoreticians aiming to develop novel theory and computational tools that apply to real-world biological problems, not simply to toy models. In addition to the examples throughout the notes above, we highlight the following publications: Mirzaev I, Gunawardena J. Laplacian dynamics on general graphs. Bull Math Biol. 2013 Nov;75(11):2118-49. Dexter JP, Gunawardena J. Dimerization and bifunctionality confer robustness to the isocitrate dehydrogenase regulatory system in Escherichia coli. J Biol Chem. 2013 Feb 22;288(8):5770-8. Xu Y, Gunawardena J. Realistic enzymology for post-translational modification: zero-order ultrasensitivity revisited. J Theor Biol. 2012 Oct 21;311:139-52. Gunawardena J. A linear framework for time-scale separation in nonlinear biochemical systems. PLoS One. 2012;7(5):e36321. doi: 10.1371/journal.pone.0036321. Gnad F, Estrada J, Gunawardena J. Proteus: a web-based, context-specific modelling tool for molecular networks. Bioinformatics. 2012 May 1;28(9):1284-6. Rowland MA, Fontana W, Deeds EJ. Crosstalk and competition in signaling networks. Biophys J. 2012 Dec 5;103(11):2389-98. Deeds EJ, Bachman JA, Fontana W. Optimizing ring assembly reveals the strength of weak interactions. Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2348-53. Harmer R, Danos V, Feret J, Krivine J, Fontana W. Intrinsic information carriers in combinatorial dynamical systems. Chaos. 2010 Sep;20(3):037108. Kolokotrones T, Van Savage, Deeds EJ, Fontana W. Curvature in metabolic scaling. Nature. 2010 Apr 1;464(7289):753-6. Goentoro L, Shoval O, Kirschner MW, Alon U. The incoherent feedforward loop can provide foldchange detection in gene regulation. Mol Cell. 2009 Dec 11;36(5):894-9. Feret J, Danos V, Krivine J, Harmer R, Fontana W. Internal coarse-graining of molecular systems. Proc Natl Acad Sci U S A. 2009 Apr 21;106(16):6453-8. 13 Ways to understand drug action at a new level, contributing to the founding of Harvard Medical School's Program in Therapeutic Science Our Department was instrumental in developing the intellectual framework for the Systems Pharmacology Initiative (led by Peter Sorger) that aims to use mathematical and computational approaches to better understand and predict the action of drugs. The Systems Pharmacology Initiative is now a major component of the School's Program in Therapeutic Science. Efforts in the Kirschner lab have led to new computational methods for better predicting drug combinations. Encouraging progress has already been made, as reported in the publications below. Niepel M, Hafner M, Pace EA, Chung M, Chai DH, Zhou L, Schoeberl B, Sorger PK. Profiles of basal and stimulated receptor signaling networks predict drug response in breast cancer lines. Sci Signal. 2013 Sep 24;6(294):ra84. Tang Y, Xie T, Florian S, Moerke N, Shamu C, Benes C, Mitchison TJ. Differential determinants of cancer cell insensitivity to antimitotic drugs discriminated by a one-step cell imaging assay. J Biomol Screen. 2013 Oct;18(9):1062-71. Fallahi-Sichani M, Honarnejad S, Heiser LM, Gray JW, Sorger PK. Metrics other than potency reveal systematic variation in responses to cancer drugs. Nat Chem Biol. 2013 Nov;9(11):708-14. Flusberg DA, Roux J, Spencer SL, Sorger PK. Cells surviving fractional killing by TRAIL exhibit transient but sustainable resistance and inflammatory phenotypes. Mol Biol Cell. 2013 Jul;24(14):2186-200. Kleiman LB, Maiwald T, Conzelmann H, Lauffenburger DA, Sorger PK. Rapid phospho-turnover by receptor tyrosine kinases impacts downstream signaling and drug binding. Mol Cell. 2011 Sep 2;43(5):723-37. Orth JD, Kohler RH, Foijer F, Sorger PK, Weissleder R, Mitchison TJ. Analysis of mitosis and antimitotic drug responses in tumors by in vivo microscopy and single-cell pharmacodynamics. Cancer Res. 2011 Jul 1;71(13):4608-16. Bollenbach T, Kishony R. Resolution of gene regulatory conflicts caused by combinations of antibiotics. Mol Cell. 2011 May 20;42(4):413-25. Torella JP, Chait R, Kishony R. Optimal drug synergy in antimicrobial treatments. PLoS Comput Biol. 2010 Jun 3;6(6):e1000796. Gohil VM, Offner N, Walker JA, Sheth SA, Fossale E, Gusella JF, MacDonald ME, Neri C, Mootha VK. Meclizine is neuroprotective in models of Huntington's disease. Hum Mol Genet. 2011 Jan 15;20(2):294-300. Gujol TS, Peshkin L, Kirschner MW Exploiting polypharmacology for drug target deconvolution. Proceedings of the National Academy of Sciences. 2014 Epublication March 19, 2014 14