From Signal Transduction to Targeted Therapy (Fall 2010) Pin Ling ( 凌 斌 ), Ph.D. Department of Microbiology & Immunology, NCKU ext 5632

Outline Signaling Transduction - Definition - History - Mechanisms - Example Targeted Therapy - Mechanisms - Examples - Current Trend Your involvement is the key to success in this lecture.

What is Signaling Transduction? Conversion of a signal from one physical or chemical form into another. The process initiated by recognition a Signal by a Sensor (receptor, kinase or enzyme) in the cell, then converting to one or more cellular responses through a series of signal transmission.

Receptors Signal Transducers Effectors A simple scheme of signal transduction Fig 15-1 Adopted from Molecular Biology of The Cell Q: Who first gets the idea about “ Signal Transduction”? Molecules involved in this process, called Signaling Molecules

History of signaling transduction Adopted from Nobelprize.org

Rodbell’s findings Adopted from Nobelprize.org

Gilman’s findings Adopted from Nobelprize.org

Adopted from Molecular Cell Biology Current view of GPCR signaling

A simple scheme of signal transduction Fig 15-1 Adopted from Molecular Biology of The Cell Receptors Signal Transducers Effectors

Four types of surface receptors Adopted from Molecular Cell Biology GPCR Ion Channel Receptor w/o Enzyme Receptor w/ Enzyme

Adopted from Molecular Cell Biology Four common second messengers

cAMP is the first 2 nd Messenger Adopted from Nobelprize.org (1 st messenger) (2 nd messenger)

A simple scheme of signal transduction Fig 15-1 Adopted from Molecular Biology of The Cell Receptors Signal Transducers Effectors

Two types of signal transducers Enzymatic proteins: Kinase, GTPase,….etc Non-Enzymatic proteins: Adaptors, Scaffolds,...etc Post-Translation Modifications (PTMs): Phosphorylation….. Protein-Protein Interactions, Signalsome Formation Two major biochemical events in signal transduction

Examples of enzymatic proteins Adopted from Molecular Cell Biology

Adaptors in signal transduction Adopted from Molecular Cell Biology

Ras activation following EGFR signaling Adopted from Molecular Cell Biology

Ras activates the MAPK/ERK pathway Adopted from Cell Signaling

A simple scheme of signal transduction Fig 15-1 Adopted from Molecular Biology of The Cell Receptors Signal Transducers Effectors

Types of Post-Translation Modifications Phosphorylation Methylation Acetylation Ubiquitination Sumoylation Chemical groups Small peptides Palmitoylation Myristoylation Lipid groups Glycosylation Sugar groups

Features of Post-Translation Modifications 1.Most are Reversible 2.Regulate Protein Activity, Protein Localization, Protein Interaction,……etc. 3. Focus on “Protein Phosphorylation” today

Protein Phosphorylation Adopted from Nobelprize.org

Activation of a enzyme by phosphorylation

Mechanism of Phosphorylation by cAPK (PKA) Adopted from Molecular Cell Biology

G. Manning et al., Science. 2002, 298: Human Kinome protein kinases 2.Tyr & Ser/Thr kinases 3.Involve many processes 4.Dysregulation => diseases 5.Targets for therapy

(Charles Swyers, Nature 2004) Examples of kinase-associated diseases

Post-translational modifications of human nucleosomal histones

Modular interaction domains in signaling transduction (Pawson et al, Science 2003) Check more details in BIND database (Biomolecular Interaction Network Database)

Cell Jan 23;116(2): Specificity in signal transduction: from phosphotyrosine-SH2 domain interactions to complex cellular systems. Pawson Tony Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada. Science 18 April 2003: Vol no. 5618, pp. 445 – 452 Assembly of Cell Regulatory Systems Through Protein Interaction Domains Tony Pawson 1,2* and Piers Nash 1 1 Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada. 2 Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada. * To whom correspondence should be addressed. Signaling Specificity

Multiple signaling cascades form signaling networks Cell Oct 13;103(2):

Curr Opin Cell Biol Apr;14(2): M. Synder et al, Approaches to studying signaling networks

Trends in Therapies 1.Gene Therapy – genetic diseases, cancer,…etc 2.Cell Therapy – degenerative diseases (Alzheimer, Myocardial disorders….etc) 3.Targeted Therapy – cancer, immune disorders,…etc => Each has its pros and cons. Signaling Transduction => Molecular Targets => Targeted Therapy

Fig 15-1 Adopted from Molecular Biology of The Cell Receptors Signal Transducers Effectors Dysregulation of signaling molecules leads to disorders A simple scheme of signal transduction

Q1: How to do targeted therapy? Two major biochemical events in signal transduction: (1) Post-Translation Modifications: protein phosphorylation (2) Protein-Protein Interactions: ligand- receptor, protein-dimeriztion Molecules designed to block these two biochemical events

Abl, BCR-Abl, & Chronic Myelogenous Leukemia (CML) Nat Rev Cancer Mar;5(3):

Leukemogenic signaling of BCR-Abl

Development of Chronic Myelogenous Leukemia (CML) Nat Rev Cancer Mar;5(3):

Copyright ©2001 AlphaMed Press Mauro, M. J. et al. Oncologist 2001;6: Figure 1. Schematic representation of the mechanism of action of STI571 Gleevec (STI 571, Imatinib): A Small Molecule with a Big Impact

Q2: How to deal with drug resistance ? Some CML patients develop resistance or relapse to targeting small molecule (Imatinib). (1) Develop modified drug (2 nd generation kinase inhibitor) (2) Combination therapy

2 nd generation TKI -Imatinib-like compound J. Cortes et al Blood, 2009 IC 50, lower is better.

Molecules for targeted therapies (1)Small molecules: target the ATP binding site or other regions in protein kinase domain, e.g. Gleevec (to BCR-Abl) (2) Monoclonal Abs: target receptors, cytokines, other surface proteins, e.g. Herceptin (to Her), Erbitux (to EGFR) (3) Others: Decoy receptors (soluble CTLA4-Ig), Vaccines, RNAi,..etc

Targeting drugs in clinical trials

Ab-mediated signaling inhibition Adopted from Nature Biotechnology 23, (2005)

Approved mAb Cancer therapeutics

Summary 1. Signaling transduction is essential for cells to communicate with environmental stimuli. 2. It usually includes three major components: Receptor, Transducer, & Effector. 3. Two key biochemical events during signaling transduction: PTMs & Protein Interactions 4. Dysregulation of signaling molecules perturbs cellular processes then leading to disease develpoment. 5. Targeted therapy are mostly based on targeting two biochemical events.

Kinase: (seq, evolution & kinomes) Protein kinase resource: (kinase structure) Alliance for cell signaling: Phosphosite database: (in vivo phosphorylation sites) Websites for signaling transduction

Homework Gleevec has also been found to effectively treat other cancer cells such as gastrointestinal stromal tumors (GIST). However, scientists found no mutation of Abl kinase in these tumor cells. Please explain the underlying mechanism of how Gleevec is still working in this kind of cancer cells even without c-Abl mutation.

B. Druker, Cancer Cell, nd generation TKI STI 571-like compound

Kantarjian et al. Nature Reviews Drug Discovery 5, 717–718 (September 2006) | doi: /nrd2135