Cellular senescence, cancer and aging Buck Institute for Age Research Lawrence Berkeley National Laboratory September 10, 2005 SENS2, Cambridge

Suppressing cancer costs -- aging Tumor Suppressor mechanisms Aging Phenotypes Care- takers (prevent/ repair DNA damage, mutations) Gate- keepers (eliminate/arrest damaged, mutant cells) Apoptosis Senescence Deplete proliferating/ stem cell pools ---> Tissue atrophy/degeneration Deplete proliferating/stem pools Cell dysfunction ---> loss of tissue function/homeostasis Late life phenotypes, including cancer (antagonistic pleiotropy) Longevity assurance

Cellular Senescence Suppresses Cancer Cancer cells acquire mutations that abrogate the senescence response Mutations that dampen cellular senescence greatly increase susceptibility to cancer Cellular senescence is controlled by two powerful gatekeeper tumor suppressor pathways (p53 and pRB) Mouse model, human tumor data ----> importance of cell senescence for limiting cancer progression

Short/dysfunctional telomeres (REPLICATIVE SENESCENCE) DNA Damage Oncogenes Chromatin Instability Supraphysiological Mitogenic/ Stress Signals Cellular Senescence Induced by Many (Cancer-Causing) Stimuli Irreversible arrest of cell proliferation

CELLULAR SENECENCE: Complex Senescent Phenotype Irreversible Growth Arrest Resistance to Apoptosis Altered Function/Gene Expression

The senescent phenotype: Altered pattern of gene expression Cell cycle regulation Cell structure Metabolism Biologically active secreted molecules Proteinases Cytokines Growth factors

Epithelial Cells Fibroblasts AGE INCIDENCE Mutations Senescent cells CANCER

Do senescent cells disrupt normal and/or neoplastic tissue structure/function? (effects of senescent stromal fibroblasts on epithelial cells) Jean-Philippe Coppe, Pierre Desprez, Ana Krtolica, Simona Parrinello, Christopher Patil

Senescent fibroblasts disrupt morphology and function of mammary epithelial cells BM + PreS Fb BM + Sen Fb  -casein DAPI Pre-S Fb Sen Fb  -casein E-cadherin Parrinello et al., J Cell Sci, 2005

Presenescent fibroblasts Primary duct Secondary duct Senescent fibroblasts Core Core Area Number PRIMARY SECONDARYTERTIARY Senescent fibroblasts disrupt ductal morphogenesis of normal mammary epithelial cells Parrinello et al., J Cell Sci, 2005

Senescent fibroblasts stimulate proliferation of premalignant and malignant epithelial cells Krtolica A et al., Proc Natl Acad Sci, 2001

Senescent Fibroblasts Stimulate Tumorigenesis of Premalignant Epithelial Cells In Vivo Days Tumor size (mm 3 x 10) SCp2 cells alone + Presenescent Fibroblasts + Senescent Fibroblasts Krtolica A et al., Proc Natl Acad Sci, 2001

Modeling effects of senescent cells in the mouse: Oxygen matters

Senescent phenotype of mouse fibroblasts Mouse cells undergo rapid replicative senescence in culture, despite long telomeres + telomerase Presenescent Senescen t SCp2 HaCATS1 Epithelial Cell Growth HaCATSCp2 S1 Human Fibroblasts Mouse Fibroblasts (MEFs)

Severe oxidative damage causes replicative senescence of murine cells in culture Parrinello et al., Nature Cell Biol, 2003

How do senescent cells influence the behavior of neighboring cells?

The senescence-associated secretory phenotype is conserved and complex Jean-Philippe Coppe, Pierre Desprez, Ana Krtolica, Simona Parrinello, Christopher Patil

Conclusions from antibody arrays Senescent stromal cells overexpress/secrete many cytokines, proteases, growth factors (senescence secretory phenotype) There are similarities in the secretory phenotypes of senescent human and mouse stromal cells, BUT oxygen matters There are many similarities among cells induced to senesce by different stimuli

Can the senescent phenotype be reversed without reversing the senescent growth arrest?

Parrinello et al., J Cell Sci, 2005 Senescent fibroblasts stimulate MEC ductal hyperplasia through MMP-3

THANKS! Jean-Philippe Coppe Ana Krtolica Christopher Patil Simona Parrinello (U College London) Christian Beausejour (McGill U) Pierre Desprez -- CPMC Joe Gray, Rich Neve -- LBNL Kalin Kauser -- Berlex