-
[show abstract]
[hide abstract]
ABSTRACT: The aim of the present study was to detect the expression of survivin in human lung cancer and to investigate the influence of its downregulation on the biological behavior of A549 lung cancer cells. The high expression of survivin in human lung cancer was verified by immunohistochemistry. Survivin small interfering RNA (siRNA) and unrelated sequence were synthesized and the siRNA lentiviral vector was constructed. The vector was transfected into A549 lung cancer cells, in which the clone with stable expression was screened out. We blocked the expression of survivin mRNA and protein by RNA interference (RNAi) technique. The downregulation of survivin mRNA and protein expression was confirmed by real-time quantitative PCR and western blotting. The proliferative activity and growth rate of A549 cells were determined by colony formation assay and mononuclear cell direct cytotoxicity assay (MTT assay). The reconstituted basement membrane (RBM) penetrating capacity was determined by cell invasion assay. The cell movement and migratory capacity were detected by wound-healing repair assay. The results showed that the sequence-specific siRNA significantly downregulated the expression of survivin at both the mRNA and protein levels. Downregulation of survivin expression dramatically decreased the invasive and metastatic capacities of the cells, suppressed the proliferation, decelerated the rate of growth, reduced the number of clones on soft agar and decreased the capacity of RBM penetration and migration. In conclusion, survivin, which plays an important role in carcinogenesis and development of lung cancer, can be effectively downregulated using the RNAi technique.
Experimental and therapeutic medicine 06/2012; 3(6):1010-1014.
-
[show abstract]
[hide abstract]
ABSTRACT: The survivin protein, a member of the inhibitors of apoptosis (IAP) family, has gained popularity as a therapeutic target for cancer due to its selective expression in tumor cells and its significant involvement in tumor cell viability. The aim of this study was to investigate the effect of the survivin-small interfering RNA (siRNA) plasmid on survivin expression in the human lung cancer cell line, A549, and to observe its effects on apoptosis and proliferation of A549 cells. A549 human lung cancer cells were transfected with survivin-targeting siRNA. The downregulation of survivin expression was determined by real-time polymerase chain reaction and western blotting. The proliferation of A549 cells was determined by MTT assay. The apoptotic rate and cell cycle distribution were analyzed by flow cytometry (FCM). Caspase-9 activity was also detected to study the apoptosis of lung cancer cells induced by siRNA against survivin. The sequence-specific siRNA efficiently and specifically downregulated the expression of survivin at both the mRNA and protein levels. Downregulation of survivin expression dramatically suppressed the proliferation of A549 cells and arrested the cells at the G (1)/G (0) phase. Caspase-9 activity was significantly increased in A549 cells transfected with siRNA against survivin. In this study, we found that survivin-specific siRNA can efficiently suppress the expression of survivin, increase apoptosis and inhibit A549 cell proliferation. Our findings further indicate the possibility that the antitumor effects of survivin-siRNA are mediated through the activation of caspase-9.
Molecular Medicine Reports 04/2012; 5(4):917-22. · 0.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Survivin and Bcl-2 are generally considered to be inhibitors of apoptosis and are frequently overexpressed in several types of human cancers. However, their role in regulating the biological behavior of non-small cell lung carcinoma (NSCLC) remains controversial. We aimed to determine the expression of survivin and Bcl-2 and explore their correlation with clinicopathological features and prognosis. The expression of survivin and Bcl-2 proteins in 62 specimens of NSCLC tissues and 30 specimens of tumor adjacent tissues was detected using immunohistochemistry. The correlation between protein expression and clinicopathological features and prognosis was analyzed. The percentage of survivin-positive samples obtained from NSCLC tissues was 58.06% (36/62), which was significantly higher compared to that in normal lung tissues (10%, 3/30; P<0.05). Similarly, the percentage of Bcl-2-positive samples obtained from NSCLC tissues was statistically higher compared to that from normal lung tissues (51.61%, 32/62 vs. 6.67%, 2/30; P<0.05). Survivin expression was closely correlated with tumor differentiation, lymph node metastasis and TNM stage (P<0.05), while Bcl-2 expression was only associated with TNM stage (P<0.05). The expression of survivin was positively correlated with that of Bcl-2 (P<0.05). A five-year follow-up study revealed that the expression of survivin and Bcl-2 was negatively correlated with post-operative survival duration. Our findings suggest that survivin and Bcl-2 may act synergistically in the occurrence, development, invasion and metastasis of NSCLC, both of which are up-regulated in NSCLC tissues. The co-expression of survivin and Bcl-2, which is closely related to malignancy, may serve as a biomarker for predicting prognosis.
Molecular Medicine Reports 03/2012; 5(6):1409-14. · 0.42 Impact Factor
