Enhancing the C-48 STAT3 InhibitorDarnell FordDr. Nagarajan VaidehiDepartment of ImmunologyCity of Hope, Duarte, CaSoCalBSI 2008

Background Signal Transducer and Activator of

Transcription 3 STAT3 mediates the expression of various genes

in response to cell stimuli STAT3 possesses oncogenic potential and anti-

apoptotic activities Constitutive activation of STAT3 found in over 20

human cancers Effective and STAT3 selective inhibitors have

not been found

Objectives Create a Derivative of Lead Compound That

Possesses an Enhanced Binding Affinity and Selectivity to STAT3

Learn Maestro and Glide Construct ligands that contain rational additions to the

lead compound and create a file for those ligands Formulate a list of lead compound derivatives using

computer simulation and combinatorial screening whose binding energy scores are most favorable

Overview STAT3

pathway and structure C-48, the inhibitor/lead compound

Maestro Glide Prime

Scoring Rankings Future Steps

Signal Transduction Pathway

Activates Transcription

www.biocarta.com/pathfiles/m_stat3Pathway.asp

Dimerized and Localized to the nucleus

Crystal Structure of STAT3 Dimer

Connector Domain

Src Homology 2 Domain(SH2)

Coiled Domain

DNA Binding Domain

www.brown.edu/news/2004-05/04-072.jpg

STAT3 (Cont.) C-48

Tested experimentally at City of Hope Inhibits the dimer formation

Inhibits STAT3 DNA interaction Kills tumor cells

Promotes apoptosis in tumor cells

Goal: Derivatize C-48 to improve its binding affinity, efficacy, and selectivity with STAT3

C-48

C-48 (cont.) Environment

Arginine, Serine, Glutamine

Polar and hydrophilic

Distance between Heavy Atoms Average of 3.0Å

Changes Added CH2OH ARG

553

GLU 555

GLU 557

SER 556

C-48 (cont.) Environment

Cysteine, Isoleucine, Methionine

Non-polar, Hydrophobic

Distance between heavy atoms Average of 4.8 Å

Changes Six carbon ring Hydroxyl group

CYS 1164

ILE 1105

MET 1100

ILE 518

C-48 (cont.) Environment

Asparagine, Serine, Glutamine, Arginine

Highly Polar, Hydrophilic

Distance Between Heavy Atoms Average of 3.5 Å

Changes Additional

Nitrogen Atom NH2 and OH

ASN 1099

GLU 517

ARG 553

SER 556

Maestro Product of Schrödinger

Designer of high performance computational technology Drug design software and general molecular modeling

Graphical User Interface (GUI) for all Schrodinger programs Tools to

build, display, and manipulate structures organize, monitor, submit, and visualize results from calculations

on structures

http://schrodinger.com

Maestro

Maestro

Glide Prime

Ligand DockingBinding Mode

Predictions

Protein Structure Prediction

Ligand Induced Fit

Bind Energy Kcal/mol Glidescore

C-48.1 -68.38266799 -5.013944

C-48 -66.21636123 -5.085172

C-48.2 -65.35318568 -4.634376

C-48.3 -64.4949882 -5.362646

C-48.4 -63.73290669 -7.198051

C-48.5 -62.89760652 -7.288412

C-48.6 -60.56520178 -4.944679

C-48.7 -60.01377425 -7.843053

C-48.8 -59.73756404 -7.708974

C-48.9 -59.25700937 -7.748304

C-48.10 -59.11006754 -6.536931

C-48.11 -58.85839462 -6.122557

C-48.12 -58.64722779 -4.387408

C-48.13 -57.31288197 -4.81971

C-48.14 -57.07387623 -6.655349

C-48.15 -56.07602975 -6.891117

C-48.16 -54.98854927 -4.520704

C-48.17 -54.4892643 -6.602773

C-48.18 -53.62711263 -3.81365

C-48.19 -53.02512129 -4.507152

Future Steps

Testing 1: Dish Culture

Testing 2: Lab Animals

Clinical Trials

FDA Approval

Chemist

Manufacturer

Acknowledgements Dr. Nagarajan Vaidehi Dr. JingPing Lin Dr. Supriyo Bhattacharya Dr. Spencer Hall Dr. Sandra Sharp Dr. Jamil Momand Dr. Wendie Johnston Dr. Nancy Warter-Perez SoCalBSI 2008