Buck Institute for Age Research 29 April, 2011 Serono Symposium on Reproductive Ageing Taormina, Italy The double-edged sword of cellular senescence Lawrence Berkeley National Laboratory I am so sorry I cannot be with you on the beautiful island of Sicily Ucria Messina My grandparents in their early-mid 20’s My father in his late 50’s AGING: My grandmother in her late 70’s What IS Aging? Aging is a process that changes a fit (young) organism into a less fit (old) organism Aging = susceptibility to disease Neurodegeneration, Osteoporosis memory loss Macular degeneration Heart disease Vascular disease Sarcopenia, frailty Diabetes Decreased lung, kidney, etc function CANCER Aging = susceptibility to disease AGE CANCER HEART FAILURE STROKE DEMENTIA MULTI-SYSTEM DECLINE BASIC AGING PROCESS Which is the basic aging process that link aging and age-related disease? Age-related diseases are (mostly) degenerative Neurodegeneration, Osteoporosis memory loss Macular degeneration Heart disease Vascular disease Sarcopenia, frailty Diabetes Decreased lung, kidney, etc function CANCER Is there a common biology that links cancer, degenerative disease and aging? (a working hypothesis …. and model) Suppressing cancer costs -- aging Tumor Suppressor Aging mechanisms Phenotypes Late life phenotypes, including cancer (antagonistic pleiotropy) Care- Gate- Apoptosis takers keepers Deplete proliferating/ prevent/repair eliminate/ stem cell pools ---> DNA damage, arrest Tissue atrophy/degeneration mutations damaged/ mutant cells Senescence Deplete proliferating/stem pools Longevity assurance Cell dysfunction ---> loss of tissue function/homeostasis What is cellular senescence? Mitotically competent cell post-mitotic Induced by many potentially oncogenic stresses Requires functions of p53 and pRB tumor suppressor proteins Senescent remain viable, metabolically active, and do not die Senescent Cells Accumulate In Vivo With Increasing Age Human, rodent and primate skin, retina, liver, spleen, aorta, kidney, etc. At Sites of Age-Related Pathology Venous ulcers, atherosclerotic plaques, arthritic joints Benign prostatic hyperplasia, pre-neoplastic lesions growth arrest SASP SA-Bgal p16INK4a DNA damage foci Heterochromatin (DNA-SCARS/TIF) foci (SAHF) Dimri et al., Campisi, Curr Opin Genet, 2010 PNAS, 1995 Rodier & Campisi, J Cell Biol, 2011 Why might senescent cells drive aging? The senescent phenotype is complex Irreversible Growth Arrest Resistance Altered to Function/Gene Apoptosis Expression Senescent cells secrete biologically active molecules that can alter the tissue microenvironment Senescence-associated secretory phenotypes (SASPs) SEN PRE yellow = overexpressed; blue = underexpressed Coppe et al., PLoS Biol, 2008 Biological Activities of the SASP Pro-inflammatory -- HIGHLY CONSERVED (e.g., IL-1, 6, 8, GM-CSF, MCPs, etc) Growth stimulatory (e.g., GRO-alpha, HGF) Pro-angiogenic/invasion/migration (e.g., VEGF, IL-6,8, MMPs) Immune clearance and evasion (e.g., IL1, IL6, shed cell surface receptors) The SASP is pro-inflammatory Inflammation destructive immune cell infiltration autocrine paracrine immune-independent action of inflammatory factors Inflammation causes or contributes to virtually every major age-related pathology, including cancer Aged tissues are inflamed: “sterile” inflammation The SASP has potent paracrine activities The SASP has potent paracrine activities disrupts normal (mammary) tissue structure and function (MMP3) non-SEN Fb SEN Fb malignant phenotypes in pre-malignant or non-aggressive cells (IL-6, IL-8, GROa) non-SEN Fb CM SEN Fb CM Fb No stimulates premalignant con- version and malignant SEN - tumorigenesis in vivo Non (inflammation, vascularization) SEN Krtolica et al, PNAS, 2001; Parrinello et al, J Cell Sci, 2005; Coppe et al, J Biol Chem, 2006; Coppe et al., PLoS Biol, 2008; Coppe et al, 2010; Krtolica et al, Differentiation, 2011 What causes the SASP? The SASP a (epi)genomic damage response The SASP* is a response to persistent DNA damage signaling (*inflammatory cytokine secretion) Epigenomic modifiers (e.g., histone deacetylases) also elicit a DDR and senescence growth arrest, accompanied by ATM and p53 activation 0 12h 2d 3d 4d 5d 7d p53 p53ser15 (also p-ATM, p-CHK2) actin Rodier et al., Nature Cell Biol, 2009 The DDR oversimplified ATM, ATR, etc NBS1 H2AX, CHK2 many other substrates p53 REPAIR SENESCENCE APOPTOSIS SASP??X DDR oversimplified ATM etc. H2AX, many other substrates SASP? p53 REPAIR SENESCENCE The SASP* is a response to persistent DNA damage signals (*inflammatory cytokine secretion) ATM kd before irradiation AMT kd 10 d after irradiation IL-6 secretion IL-6 secretion Rodier et al., Nature Cell Biol, 2009 DDR proteins upstream of p53 drive inflammatory cytokine secretion by senescent cells ATM NBS1 H2AX, many other CHK2 substrates p53 inflammation REPAIR SENESCENCE Rodier et al., Nature Cell Biol, 2009 Why does the SASP occur? SASP components can, in the short term, facilitate tissue repair SASP components also signal the innate immune system to stimulate their own clearance Immune clearance is only 80-90% effective, due to high expression of MMPs MMPs produced by senescent cells limit fibrosis during wound healing DAMAGE ATM AGING? REPAIR p53 CANCER Senescence SASP Longevity Longevity Pathways? Tissue repair INFLAMMATION Rapamycin in use to suppress organ transplant rejection Rapamycin in advanced clinical trials as anti-cancer therapy Rapamycin extends life span in mice mTOR, rapamycin and inflammation: promises and puzzles Promise: Rapamycin suppresses the SASP 15000 10000 S6K1 pg/cell/24 h pg/cell/24 p-S6 6 - 5000 S6 6, 10 6, - actin IL 0 XRA DMSO XRA Rapamycin Mock DMSO -1.5 Mock Rapamycin Arturo Orjalo, Remi-Martin Laberge, Chris Patil – Pankaj Kapahi -- unpublished Promise: Rapamycin does NOT suppress the (tumor suppressive) senescence growth arrest Puzzle: Rapamycin suppresses senescence-associated IL-6 secretion after a single 24 h exposure Puzzle: Rapamycin suppresses senescence-associated IL-6 transcription (mRNA levels)! Fold mRNA Decrease IL-6 9 IL-8 11 GROa 8 MIP2 9 IL-1a <2 (NS) Orjalo et al, PNAS, 2009 Inflammation Bhaumik et al, Aging, 2009 Freund et al, EMBO J, in press Rapamycin suppresses the translation of IL-1a low high PRE SEN SEN+rapa Recombinant IL-1α rescues rapa –suppressed IL-6 secretion Pretreatment of senescent fibroblasts with rapamycin suppresses their ability to stimulate tumor growth + Sen X DMSO + Sen X Rapa 0.00006 0.00006 0.00005 0.00005 0.00004 0.00004 0.00003 0.00003 0.00002 0.00002 fluo rel unit rel fluo unit rel fluo 0.00001 0.00001 0.00000 0.00000 W1 W2 W3 W4 W5 W6 W7 W1 W2 W3 W4 W5 W6 W7 weeks after injection weeks after injection Genomic/epigenomic damage, oxidative stress, etc DDR mTOR rapa NF-kB IL-1a IL-6,-8, etc INFLAMMATION (SASP) AGE-RELATED DISEASE DEGENERATION and CANCER THANKS! Past lab members Present lab members Christian Beausejour (Montreal U) Albert Davalos Dipa Bhaumik (Buck Institute) Peter de Keizer Jean-Philippe Coppe (Dynamic Throughput) Mario Demaria Pierre Desprez (CA Pacific Med Cntr) Adam Freund Ana Krtolica (StemLife Inc) Remi-Martin Laberge Francis Rodier (Montreal U) Julie Mangada Art Orjalo Chris Patil Collaborators Kevin Perrott Pete Nelson/Yu Sun (Fred Hutch) Michael Velarde Jan Vijg (Einstein Coll Med) Chris Wiley Steve Yannone (LBNL) Lili Zhou Paul Yaswen (LBNL) Ying Zou David Raulet (UCB) Pankaj Kapahi (Buck Inst) Simon Melov (Buck Inst).