Knockdown of survivin expression by small interfering RNA reduces the clonogenic survival of human sarcoma cell lines independently of p53

Abstract

Survivin, a member of the inhibitors-of-apoptosis gene family, is overexpressed in many tumor types. Survivin is a prognostic marker of soft-tissue sarcomas, but the downregulation of survivin expression and the possible dependency of survivin downregulation on p53 in these tumors have not been investigated. Therefore, we applied small interfering RNA (siRNA) to knock down the expression of survivin in five human sarcoma cell lines with wild-type or mutant p53 alleles. Compared with survivin mRNA expression in the nonsense siRNA-treated sarcoma cell lines, expression after treatment with survivin-specific siRNA was reduced by 73-88%; survivin protein expression was reduced by 52-81%. This finding was coupled with a reduction in clonogenic survival ranging from 65-86%. However, less than 10% of cells treated with survivin-specific siRNA underwent apoptosis. Cell-cycle and morphologic analyses showed that after a dramatic increase in the number of treated cells in the G2/M phase, some of the cells became polyploid; this result indicates that mitosis of a substantial number of treated cells was incomplete. Our findings suggest that survivin-specific siRNA could be a selective treatment to kill sarcoma cells regardless of the presence or absence of wild-type p53 alleles.

The effects of knockdown of wild-type survivin, survivin-2B or survivin-Δ3 on the radiosensitization in a soft tissue sarcoma cells in vitro under different oxygen conditions

“…[11][12][13][14] In a previous study, in five soft tissue sarcoma cell lines a reduced plating efficiency and occurrence of polyploidy independent of the p53 gene status was observed after treatment with survivin-specific siRNA. 15 This finding is in accordance with results of survivin knockdown experiments in other cancer cell lines. 5,[16][17][18][19][20] Furthermore, survivin overexpression was associated with radioresistance in tumor cell lines.…”

Survivin as a Radioresistance Factor, and Prognostic and Therapeutic Target for Radiotherapy in Rectal Cancer

“…Thus, at the time of irradiation, the cells were blocked in a more radiosensitive stage of the cell cycle. Kappler et al (22) have also recently shown a marked G 2 -M arrest, an impaired mitosis, and an increased number of polyploid cells after survivinspecific siRNA treatment in five human sarcoma cell lines. This is in line with our observations of a reduced cell viability in the MTT test (Fig.…”

Centrosome amplification induced by survivin suppression enhances both chromosome instability and radiosensitivity in glioma cells

“…It inhibits apoptosis (Altieri, 2001) and is involved in the spindle checkpoint and the regulation of proper chromosomal segregation during mitosis by acting as a member of the chromosomal passenger protein family (Li et al, 1998;Adams et al, 2001). A number of studies have demonstrated that the suppression of survivin results in cells with multipolar mitotic spindles that are either multinucleated or aneuploid (Li et al, 1999;Beltrami et al, 2004;Kappler et al, 2004). Some studies have also indicated that aneuploidy promotes chromosome instability (CIN) in glioma and cervical carcinoma cells (Nitta et al, 2002;Olaharski et al, 2006).…”