enhancement of stress-induced apoptosis in b-lineage cells by caspase-9 inhibitor
DESCRIPTION
Enhancement of stress-induced apoptosis in B-lineage cells by caspase-9 inhibitor. Nisha Shah et al., BLOOD.2004;104:2873-2878. 生科四甲 王彥閔 91390063. Introduction. B-lineage (BLIN) Acute lymphoblastic leukemia (ALL) cell line : BLIN-3, BLIN-4L Caspase-9 inhibitor (C9i) - PowerPoint PPT PresentationTRANSCRIPT
Enhancement of stress-induced apoptosis in B-
lineage cells by caspase-9 inhibitor
Nisha Shah et al., BLOOD.2004;104:2873-2878
生科四甲
王彥閔
91390063
IntroductionIntroduction B-lineage (BLIN) Acute lymphoblastic leB-lineage (BLIN) Acute lymphoblastic leukemia (ALL) cell line : BLIN-3, BLIN-4ukemia (ALL) cell line : BLIN-3, BLIN-4LL
Caspase-9 inhibitor (C9i) Caspase-9 inhibitor (C9i) Pan-caspase inhibitor (PCi)Pan-caspase inhibitor (PCi) Mitochondria transmembrane potential Mitochondria transmembrane potential (Δψm )(Δψm )
TMRE : TMRE : 螢光染劑,偵測粒線體膜電位下降螢光染劑,偵測粒線體膜電位下降 YO-PRO :YO-PRO : 螢光染劑,偵測細胞滲透力改變螢光染劑,偵測細胞滲透力改變
Propidium Iodide (PI): Propidium Iodide (PI): 染劑,染劑,染凋亡晚染凋亡晚期細胞期細胞
Annexin V (AV) : Annexin V (AV) : 染劑,染劑,與細胞內膜的 與細胞內膜的 Phosphatidylserine (PS) 結合,主要染早期結合,主要染早期凋亡的細胞凋亡的細胞
BID : BID : 促使細胞凋亡的蛋白促使細胞凋亡的蛋白 PARP : caspase substrate PARP : caspase substrate Staurosporine (STSP) : apoptosis induStaurosporine (STSP) : apoptosis inducercer
Etoposide (ETOP): apoptosis inducerEtoposide (ETOP): apoptosis inducer
接受凋亡信號接受凋亡信號
凋亡調控分子間的交互作用凋亡調控分子間的交互作用
蛋白水解蛋白水解酶酶 (caspase)(caspase) 的活化的活化
細胞凋亡的連鎖反應 細胞凋亡的連鎖反應 (ex. Substrate cleavage)(ex. Substrate cleavage)
Apoptosis process
Caspase Caspase 的分類的分類 Initiator caspase : Initiator caspase : Caspase8Caspase8 、、
Caspase2Caspase2 、、 Caspase Caspase 99 、、 Caspase10Caspase10
Executioner caspase : Caspase3Executioner caspase : Caspase3 、、 CasCaspase6pase6 、、 Caspase7Caspase7
Initiator executioner substrate cleavage DNA fragmentation apoptosis
ex. PARPinitiator
initiator
executioner
Apoptosis Two main pathways :
The extrinsic pathway: cell surface death receptors such as CD95/Fas.The intrinsic or mitochondrial pathway : stress, genotoxic agents, or cytokine deprivation.
ResultsResults
Figure 1. C9i enhances apoptosis within 4 hours following removal of BLIN-3 and BLIN-4L cells from fibroblast monolayers.
Figure 2. C9i induces changes in cell permeability and loss of ΔψmΔψm in a dose-dependent manner.Result: reflects a concomitant change in cell membrane permeability and loss of ΔψmΔψm.
Figure 3. PARP cleavage occurs following treatment of BLIN-3 and BLIN-4L with C9i.Result: The degree of PARP cleavage in the presence of C9i(greater in BLIN-3 cells than BLIN-4L cells) correlated with the percentage of annexin V cells.
Figure 4. BLIN leukemic cells are sensitive to C9i independent of culture conditions.
Result:This result suggestedthat C9i could also promote apoptosis in nonstressed,healthy cells.
Figure 5. Leukemic cell lines vary in their sensitivity to C9i.Result: the leukemic cell lines weregenerally responsive to both C9i and staurosporine, or responsiveto neither.
Figure 6. Reduction of caspase-9 in BLIN-4L.
71%
78 %
86%
91%
Figure 7. Caspase-9–deficient BLIN-4L cells show increased apoptotic sensitivity to staurosporine.Result: It is noteworthy that caspase-9–deficient cells incubated in medium alone also underwent a significantly greater degree of apoptosis than control siRNA-treated cells.
DiscussionDiscussion
Enhancement of apoptosis was unique to treatment with C9i.
C9i is not simply promoting stress-induced apoptosis.
It is conceivable that loss of caspase-9 triggers a compensatory pathway involving another caspase (eg, caspase-2).
ConclusionConclusion The sensitivity of B-lineage ALL cell lines and some other leukemia/lymphoma cell lines to C9i alone suggests that it transduces a proapoptotic signal in some cells.
The apoptotic enhancement induced by C9i and/or reduction in caspase-9 could form the foundation for a new approach to enhancing apoptosis in leukemic lymphoid cells.
THE ENDTHE END