Natalia Trempolec A.R.Nebreda laboratory Why communication is important – introduction into the world of cell signaling Natalia Trempolec A.R.Nebreda laboratory Crazy about biomedicine, 01.06.2013

Outline Human body complexity Homeostasis How do cell communicate – cell signaling Cancer initiation and metastasis p38 MAPK – an important negotiator Synthetic lethality – how to get read of cancer without killing the patient

Complexity of the human body Cells Complexity of the human body Tissues Organs Human body

How it is possible from 1 CELL obtain human body made of trillions of different cells? 2. Cell differentiation 1. Cell proliferation

Cell signaling – or how do cell mantain homeostasis Homeostasis is the ability for the body to regulate its inner environment to ensure stability no matter what is happening in the outside environment Homeostasis controls: blood pressure body temperature respiration rate blood glucose levels which are maintained within a range of normal value HOMEOSTASIS Uncontrolled Controlled Disease cancer Metabolic changes Positive feedback loop body senses a change and activates mechanisms that accelerates that change Negative feedback loop deviation from a set point causes a response that moves the system back to the set point

How cells communicate with each other – introduction into cell signaling Reception Cellular response Transduction First messanger (ligand) Receptor + Second messanger: cAMP or cGMP DAG Ca2+ Protein modification Changes of enzymatic activity 6

How cells communicate with each other – introduction into cell signaling 1. Endocrine signaling Signaling molecule hormone Long distance blood vessels System involved: nervous - information endocrine cell – release of hormons bloodstream - transport target cell Hormones regulate: metabolism growth and development tissue function sleep mood

How cells communicate with each other – introduction into cell signaling Other factors Example of endocrine signaling

Signaling can regulate: How cells communicate with each other – introduction into cell signaling 2. Paracrine signaling Signaling molecule protein, peptide, non organic ions Short distance extracellular enviroment, local action Important facts: Specific - each of the signaling molecule has to be percepted by apopriate receptor Not cell type specific - one type of the cell can affect (by secreatin paracrine molecules) another type of the cell Signaling can regulate: cell proliferation cell death or survival migration Differentiation Metabolism other

How cells communicate with each other – introduction into cell signaling Example of paracrine signaling

Examples of autocrine signaling: How cells communicate with each other – introduction into cell signaling 3. Autocrine signaling Examples of autocrine signaling: Self stimulation - immune cells produce factors which after secretion, are recieved by the same cell – and leads to amplification of the signal Positive feedback loop – cancer cells in order to proliferate and avoid apoptosis produce survival and proliferation factors which positively affect cell viability Signaling molecule protein (also hormone), peptide Short distance extracellular enviroment

How cells communicate with each other – introduction into cell signaling Example of autocrine signaling

How cells communicate with each other – introduction into cell signaling 4. Juxtacrine signaling Signaling molecule protein, sugar, lipid, inside the membrane Close contact membrane nanotubes, „bridges” Important facts: Cell-to-cell contract is required Is important during development and generation of large compact structures

Why it is important to mantain an equilibrium? Normal cell division Cell damage DNA damage without repair Cell commits suicide Cancer cell division Cell damage Uncontrolled cell division DNA damage without repair More DNA damage without repair 14

When everything goes wrong - cancer initiation and metastasis Cancer cells invade tumor border Cancer migration Intravasion of blood system Arrest extravasion Micrometastasis Progressive metastasis and angiogenesis 15

Signal transduction - cascade of phosphorylation events Phosphorylation cascade is a sequence of events where one enzyme phosphorylates another, causing a chain reaction leading to the phosphorylation of thousands of proteins. Kinase - type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP to specific substrates All those events lead to signal transduction. As a consequence – binding of ONE messanger molecule to the receptor can cause multiple cellular changes

And everything starts with the proteins Ubiquitination Phosphorylation Sumoylation

p38 MAPK is a key player in information delivery and homeostasis Family of protein kinases Plays an important role in the cascades of cellular responses evoked by extracellular stimuli such as osmotic stress, UV, other secreated factors Consists of four isoforms – p38α, p38β, p38γ and p38δ Signal transduction is based on posttranslational modification of target protein via phosphorylation After phosphosphorylation protein changes its conformation which leads to its activation Inhibition of activity can be obtain by dephosphorylation using phosphatases After activation, p38 MAPK targets its substrates By phosphorylating them can lead to their activation or inhibition

p38 MAPK is a kinase with multiple faces Inflammation Cell cycle regulation Apoptosis or cell death Proliferation Cell differentiation Migration Survival Reactive oxygen spices regulation Cytoskeleton maintenance Metabolism Other???

p38 MAPK is a key player in information delivery and homeostasis Why it is important to maintain homeostasis? Disease Insulin resistance in diabetes rheumatoid arthritis Inflamatory reaction Cancer

p38 MAPK – good or bad player? 1. Key regulator of cell cycle progression 2. Activation of stress response programm after stimuly 3. Important in early stages of embriogenesis, differentiation 4. Act as suppressor of tumorigenesis (induced cell cycle arrest and cell death) But!!! 5. Aslo can be involved in increase in proliferation Why??? Everything depends on the genetic background 6. Is involved in angiogenesis

Cancer „addiction” Normal cell Cellular metabolism Replication errors UV light exposure Ionizing radiation Cytotoxic treatment Checkpoint activation Transcriptional program activation Apoptosis DNA repair: BER NER MMR HR NHEJ Single stranded DNA damage Double stranded DNA damage Every of the pathway of DNA repair has different subpathways (as a backup)

Cancer „addiction” Cancer cell How it can be used? Cellular metabolism Replication errors UV light exposure Ionizing radiation Cytotoxic treatment Checkpoint activation Transcriptional program activation Apoptosis DNA repair: BER NER MMR HR NHEJ Single stranded DNA damage Double stranded DNA damage How it can be used? To find a new treatment for cancer – without killing a normal cells

Synthetic lethality Synthetic lethality arises when a combination of mutations in two or more genes leads to cell death, whereas a mutation in only one of these genes does not, and by itself is said to be viable

Oscar story of BRCA1/2 and PARP Synthetic lethality – taking an advantage during cancer treatment Oscar story of BRCA1/2 and PARP

How to test whether p38 has a synthetic lethal „partner”? p38 and synthetic lethality? How to test whether p38 has a synthetic lethal „partner”?

Signalling and Cell Cycle Laboratory THANKS! Signalling and Cell Cycle Laboratory