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.
ABSTRACT: ObjectiveTo investigate the effects of interleukin-18 (IL-18) on implanted Lewis lung cancer in suppressing angiogenesis and lymphangiogenesis.
MethodsOne week after hypodermic inoculation of Lewis cells, sixteen tumor-bearing syngeneic mice were randomly divided into two
groups. The mice in the treatment group (group A) were intraperitoneally injected with the IL-18 and in the control group
(group B) were intraperitoneally injected with normal saline for 7 days. The mice were killed on day 19. The morphology of
the tumors was studied, the growth curve was described and the tumor inhibition rate was calculated. The numbers of metastasized
pulmonary colonies were calculated using hematoxylin-eosin (HE) staining. The vascular endothelial growth factor A (VEGF-A),
vascular endothelial growth factor C (VEGF-C), microvessel density (MVD) and lymphatic microvessel density (LMVD) in tumor
mass were measured by immunohistochemistry staining (IHCS).
ResultsIn the group A, the tumor volume, tumor weigh, lung metastatic nodules, expression of VEGF-A and VEGF-C, MVD were all decreased
significantly (P<0.01 or P<0.05). The tumor inhibition rate was 75% and the inhibition rate of lung metastatic nodules was 61%. The LMVD in group A
was also lower than group B, but without significant difference (P>0.05).
ConclusionIL-18 could suppress the tumor growth and metastasis of implanted Lewis lung cancer by way of down-regulating VEGF-A and VEGF-C
expression, suppressing angiogenesis and lymphangiogenesis.
Key wordsInterleukin-18-Lung cancer-VEGF-LMVD
Chinese Journal of Cancer Research 04/2012; 22(4):303-309. · 0.18 Impact Factor
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