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Persistent DNA damage signalling triggers senescence-associated inflammatory cytokine secretion.

Rodier F, Coppé JP, Patil CK, Hoeijmakers WA, Muñoz DP, Raza SR, Freund A, Campeau E, Davalos AR, Campisi J - Nat. Cell Biol. (2009)

Bottom Line: Cytokine secretion occurred only after establishment of persistent DNA damage signalling, usually associated with senescence, not after transient DNA damage responses (DDRs).ATM was also essential for IL-6 secretion during oncogene-induced senescence and by damaged cells that bypass senescence.Thus, in addition to orchestrating cell-cycle checkpoints and DNA repair, a new and important role of the DDR is to allow damaged cells to communicate their compromised state to the surrounding tissue.

View Article: PubMed Central - PubMed

Affiliation: Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.

ABSTRACT
Cellular senescence suppresses cancer by stably arresting the proliferation of damaged cells. Paradoxically, senescent cells also secrete factors that alter tissue microenvironments. The pathways regulating this secretion are unknown. We show that damaged human cells develop persistent chromatin lesions bearing hallmarks of DNA double-strand breaks (DSBs), which initiate increased secretion of inflammatory cytokines such as interleukin-6 (IL-6). Cytokine secretion occurred only after establishment of persistent DNA damage signalling, usually associated with senescence, not after transient DNA damage responses (DDRs). Initiation and maintenance of this cytokine response required the DDR proteins ATM, NBS1 and CHK2, but not the cell-cycle arrest enforcers p53 and pRb. ATM was also essential for IL-6 secretion during oncogene-induced senescence and by damaged cells that bypass senescence. Furthermore, DDR activity and IL-6 were elevated in human cancers, and ATM-depletion suppressed the ability of senescent cells to stimulate IL-6-dependent cancer cell invasiveness. Thus, in addition to orchestrating cell-cycle checkpoints and DNA repair, a new and important role of the DDR is to allow damaged cells to communicate their compromised state to the surrounding tissue.

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Loss of p53 accelerates PPDF formation and IL-6 secretion(a) Replicatively senescent HCA2 cells were infected with the indicated lentiviruses and IL-6 secretion was analyzed 3−4 PDs following reversal of the senescence arrest. IL-6 secretion is reported as 10−6 pg/cell/day on a log scale (n= number of cell populations analyzed).(b) Early passage HCA2 cells were infected with a GSE22-expressing retrovirus, selected for 4 d (∼3 PDs) and IL-6 secretion was measured ∼2 PDs later. Cells were cultured for the indicated PDs and assessed for 53BP1 foci (top panel) and IL-6 secretion (lower panel) (10−6 pg/cell/day on a log scale) (n= number of cell populations analyzed). Because GSE22 prevents p53 tetramerization, which is required for transactivation and rapid degradation, GSE22-expressing cells contained abundant inactive p53 protein (see Supplementary Information, Fig. S3a).(c) Early passage HCA2 cells (PD35) were infected with lentiviruses expressing either shp53 or eGFP, selected and cultured until PD55, and analyzed for IL-6 secretion (10−6 pg/cell/day on a log scale).(d) Two HCA2-GSE22 populations were infected with a retrovirus expressing hTERT and analyzed for 53BP1 foci and IL-6 secretion as described above.
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Figure 3: Loss of p53 accelerates PPDF formation and IL-6 secretion(a) Replicatively senescent HCA2 cells were infected with the indicated lentiviruses and IL-6 secretion was analyzed 3−4 PDs following reversal of the senescence arrest. IL-6 secretion is reported as 10−6 pg/cell/day on a log scale (n= number of cell populations analyzed).(b) Early passage HCA2 cells were infected with a GSE22-expressing retrovirus, selected for 4 d (∼3 PDs) and IL-6 secretion was measured ∼2 PDs later. Cells were cultured for the indicated PDs and assessed for 53BP1 foci (top panel) and IL-6 secretion (lower panel) (10−6 pg/cell/day on a log scale) (n= number of cell populations analyzed). Because GSE22 prevents p53 tetramerization, which is required for transactivation and rapid degradation, GSE22-expressing cells contained abundant inactive p53 protein (see Supplementary Information, Fig. S3a).(c) Early passage HCA2 cells (PD35) were infected with lentiviruses expressing either shp53 or eGFP, selected and cultured until PD55, and analyzed for IL-6 secretion (10−6 pg/cell/day on a log scale).(d) Two HCA2-GSE22 populations were infected with a retrovirus expressing hTERT and analyzed for 53BP1 foci and IL-6 secretion as described above.

Mentions: To determine whether the tumor suppressors p53 and pRb were required for IL-6 secretion, we used lentiviruses to express either a short-hairpin RNA against p53 (shp53), GSE22 (a dominant peptide suppressor of p53 activity1) or SV-40 T antigen (SV40LT, which inactivates p53 and pRb1) in replicatively senescent HCA2 cells. As expected1 for HCA2, which express low levels of endogenous p16INK4a, p53 inactivation reversed the senescence growth arrest and drove cells into crisis (Supplementary Information, Fig. S2a; not shown). 3−4 PDs after infection, IL-6 secretion did not decline, but rather increased (Fig. 3a). Thus, neither p53, pRB nor the senescence arrest was required for IL-6 secretion.


Persistent DNA damage signalling triggers senescence-associated inflammatory cytokine secretion.

Rodier F, Coppé JP, Patil CK, Hoeijmakers WA, Muñoz DP, Raza SR, Freund A, Campeau E, Davalos AR, Campisi J - Nat. Cell Biol. (2009)

Loss of p53 accelerates PPDF formation and IL-6 secretion(a) Replicatively senescent HCA2 cells were infected with the indicated lentiviruses and IL-6 secretion was analyzed 3−4 PDs following reversal of the senescence arrest. IL-6 secretion is reported as 10−6 pg/cell/day on a log scale (n= number of cell populations analyzed).(b) Early passage HCA2 cells were infected with a GSE22-expressing retrovirus, selected for 4 d (∼3 PDs) and IL-6 secretion was measured ∼2 PDs later. Cells were cultured for the indicated PDs and assessed for 53BP1 foci (top panel) and IL-6 secretion (lower panel) (10−6 pg/cell/day on a log scale) (n= number of cell populations analyzed). Because GSE22 prevents p53 tetramerization, which is required for transactivation and rapid degradation, GSE22-expressing cells contained abundant inactive p53 protein (see Supplementary Information, Fig. S3a).(c) Early passage HCA2 cells (PD35) were infected with lentiviruses expressing either shp53 or eGFP, selected and cultured until PD55, and analyzed for IL-6 secretion (10−6 pg/cell/day on a log scale).(d) Two HCA2-GSE22 populations were infected with a retrovirus expressing hTERT and analyzed for 53BP1 foci and IL-6 secretion as described above.
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Related In: Results  -  Collection

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Figure 3: Loss of p53 accelerates PPDF formation and IL-6 secretion(a) Replicatively senescent HCA2 cells were infected with the indicated lentiviruses and IL-6 secretion was analyzed 3−4 PDs following reversal of the senescence arrest. IL-6 secretion is reported as 10−6 pg/cell/day on a log scale (n= number of cell populations analyzed).(b) Early passage HCA2 cells were infected with a GSE22-expressing retrovirus, selected for 4 d (∼3 PDs) and IL-6 secretion was measured ∼2 PDs later. Cells were cultured for the indicated PDs and assessed for 53BP1 foci (top panel) and IL-6 secretion (lower panel) (10−6 pg/cell/day on a log scale) (n= number of cell populations analyzed). Because GSE22 prevents p53 tetramerization, which is required for transactivation and rapid degradation, GSE22-expressing cells contained abundant inactive p53 protein (see Supplementary Information, Fig. S3a).(c) Early passage HCA2 cells (PD35) were infected with lentiviruses expressing either shp53 or eGFP, selected and cultured until PD55, and analyzed for IL-6 secretion (10−6 pg/cell/day on a log scale).(d) Two HCA2-GSE22 populations were infected with a retrovirus expressing hTERT and analyzed for 53BP1 foci and IL-6 secretion as described above.
Mentions: To determine whether the tumor suppressors p53 and pRb were required for IL-6 secretion, we used lentiviruses to express either a short-hairpin RNA against p53 (shp53), GSE22 (a dominant peptide suppressor of p53 activity1) or SV-40 T antigen (SV40LT, which inactivates p53 and pRb1) in replicatively senescent HCA2 cells. As expected1 for HCA2, which express low levels of endogenous p16INK4a, p53 inactivation reversed the senescence growth arrest and drove cells into crisis (Supplementary Information, Fig. S2a; not shown). 3−4 PDs after infection, IL-6 secretion did not decline, but rather increased (Fig. 3a). Thus, neither p53, pRB nor the senescence arrest was required for IL-6 secretion.

Bottom Line: Cytokine secretion occurred only after establishment of persistent DNA damage signalling, usually associated with senescence, not after transient DNA damage responses (DDRs).ATM was also essential for IL-6 secretion during oncogene-induced senescence and by damaged cells that bypass senescence.Thus, in addition to orchestrating cell-cycle checkpoints and DNA repair, a new and important role of the DDR is to allow damaged cells to communicate their compromised state to the surrounding tissue.

View Article: PubMed Central - PubMed

Affiliation: Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.

ABSTRACT
Cellular senescence suppresses cancer by stably arresting the proliferation of damaged cells. Paradoxically, senescent cells also secrete factors that alter tissue microenvironments. The pathways regulating this secretion are unknown. We show that damaged human cells develop persistent chromatin lesions bearing hallmarks of DNA double-strand breaks (DSBs), which initiate increased secretion of inflammatory cytokines such as interleukin-6 (IL-6). Cytokine secretion occurred only after establishment of persistent DNA damage signalling, usually associated with senescence, not after transient DNA damage responses (DDRs). Initiation and maintenance of this cytokine response required the DDR proteins ATM, NBS1 and CHK2, but not the cell-cycle arrest enforcers p53 and pRb. ATM was also essential for IL-6 secretion during oncogene-induced senescence and by damaged cells that bypass senescence. Furthermore, DDR activity and IL-6 were elevated in human cancers, and ATM-depletion suppressed the ability of senescent cells to stimulate IL-6-dependent cancer cell invasiveness. Thus, in addition to orchestrating cell-cycle checkpoints and DNA repair, a new and important role of the DDR is to allow damaged cells to communicate their compromised state to the surrounding tissue.

Show MeSH
Related in: MedlinePlus