Case Study:
Selecting Effective siRNAs to Survivin
Linking Survivin
Expression to OncogenesisSurvivin (BIRC5)
expression is linked to a broad range of cancers [1]; all major
cancer types express survivin while survivin is not expressed
in noncancerous, differentiated cells [2] (see Survivin Biology,
this page). The survivin complex and its constituents appear
to be very important for cancer cell survival and for apoptotic
control [3]. In spite of these observations, the exact mechanism
by which survivin promotes oncogenesis is unclear. By altering
survivin expression through gene silencing we can assess the
effect survivin has on known indicators of apoptosis with the
aim of better understanding the role of survivin in cancer.
Survivin Biology
Survivin (BIRC5) is a 17 kDa bifunctional
protein that plays critical roles in the regulation of both
cell division and survival [4]. In many cell types, survivin
blocks apoptosis by inhibiting members of the caspase cysteine
protease family, such as caspase-9 [5], caspase-3 and caspase-7
[6]. The phosphorylation of survivin at Thr 34 by the
cyclin-dependent kinase cdc2 is believed to promote physical
interactions with caspase-9 enzyme which result in caspase-9
inhibition [7]. Survivin and cdc2 proteins comigrate at the
mitotic spindles and appear to be important for proper progression
through the cell cycle [8]. Survivin contains a single BIR
(baculovirus IAP repeat) domain, a caspase inhibitory domain,
like other IAP (Inhibitor of Apoptosis) proteins that inhibit
caspases [3]. The BIR domain facilitates binding to caspases
as well as to the HBXIP (hepatitis B X-interacting protein),
which is proposed to be a cofactor for survivin [9].
Selecting Effective siRNAs to Survivin
For this study, three Silencer® Pre-designed
siRNAs targeting human survivin were selected. To accomplish
this, we simply searched the Ambion siRNA Database (www.ambion.com/siRNA;
Figure 1) and ordered siRNAs ID# 2646, 2734, and 121294 in
standard purity (Cat# AM16708A).
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1. Selecting siRNAs Using the Ambion siRNA Database. |
Product Information
References
1. Ambrosini G, Adida C, Altieri DC. (1997) A novel anti-apoptosis gene, survivin, expressed in cancer and lymphoma. Nat Med 3:917–21.
2. Reed, JC. (2001) The Survivin saga goes in vivo. J Clinical Invest 108:965–9.
3. Johnson ME & Howerth EW (2004) Survivin: a bifunctional inhibitor of apoptosis protein. Vet Pathol 41:599–604.
4. Liu, T. Brouha B, Grossman D (2004) Rapid induction of mitochondrial events and caspase-independent apoptosis in Survivin-targeted melanoma cells. Oncogene 23:39–48.
5. Chandele A, Prasad V, Jagtap JC, Shukla R, Shastry PR. (2004) Upregulation of survivin in G2/M cells and inhibition of caspase 9 activity enhances resistance in staurosporine-induced apoptosis. Neoplasia 6:29–40.
6. Shin S, Sung BJ, Cho YS, Kim HJ, Ha NC, Hwang JI, Chung CW, Jung YK, Oh BH (2001) An anti-apoptotic protein human survivin is a direct inhibitor of caspase-3 and -7. Biochem 40:1117–23.
7. O’Connor DS, Grossman D, Plescia J, Li F, Zhang H, Villa A, Tognin S, Marchisio PC, Altieri DC (2000) Regulation of apoptosis at cell division by p34cdc2 phosphorylation of survivin. PNAS USA 97:13103–7.
8. Uren AG, Wong L, Pakusch M, Fowler KJ, Burrows FJ, Vaux DL, Choo KH (2000) Survivin and the inner centromere protein INCENP show similar cell-cycle localization and gene knockout phenotype. Curr Biol 10:1319–28.
9. Marusawa H, Matsuzawa S, Welsh K, Zou H, Armstrong R, Tamm I, Reed JC. (2003) HBXIP functions as a cofactor of survivin in apoptosis suppression. EMBO J 22:2729–40.
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