[Show abstract][Hide abstract] ABSTRACT: Survivin, a member of the inhibitor of apoptosis protein (IAP) family, is abundantly expressed in a variety of cancer cells, including lung cancer cells, resulting in low sensitivity of these cells to various apoptotic stimuli; Cisplatin (CDDP), a commonly used chemotherapeutic agent of several cancers, has a major limitation because of its toxicity at high concentration. In the present study, we constructed a plasmid encoding Survivin shRNA to knockdown survivin with low dose DDP both in vitro and in vivo. The specificity and potency of the shRNA were validated by western blot, flow cytometric and MTT in H292 lung cancers cells. In vivo, therapy experiments were conducted on nude mice bearing H292 xenograft tumors. The Survivin shRNA expression plasmid was administered systemically in combination with low-dose CDDP on a frequent basis. Assessments of angiogenesis, cell proliferation and apoptosis were performed by using immunohistochemistry against CD31, Ki67 and TUNEL assays, respectively. The results revealed that treatment with the Survivin shRNA plus low-dose CDDP reduced volume by approximately 83.13% compared with the blank control (P < 0.01), accompanied with angiogenesis inhibition (p < 0.01), tumor cell proliferation suppression (p < 0.05) and apoptosis induction (p < 0.01). Moreover, combination treatment also significantly reduced the mean tumor volume compared with other treatment alone (p < 0.05). Taken together, our study suggested that silencing of survivin sensitized H292 lung cancer cells to chemotherapy of CDDP, suggesting potential applications of the combined approach in the treatment of lung cancer.
No preview · Article · Aug 2012 · Journal of Biomedical Nanotechnology
[Show abstract][Hide abstract] ABSTRACT: In the present study, we have used plasmid-based RNA interference (RNAi) strategy to downregulate the expression of epidermal growth factor receptor (EGFR) in EGFR wild-type (H292) and mutant (H1975) lung tumor models. The targeted knockdown of EGFR by small hairpin RNA not only inhibited growth of H292 xenograft but also inhibited H1975 lung cancer cell and xenograft, which bore L858R/T790M EGFR and was resistant to EGFR tyrosine kinase inhibitors. These data demonstrated that small hairpin RNA was an effective therapy against mutant EGFR-expressing cancer cells and thus considered to be a promising strategy in the treatment of lung cancers.
No preview · Article · Nov 2011 · Cancer Investigation
[Show abstract][Hide abstract] ABSTRACT: VEGF receptor 2 (VEGFR2) inhibitors, as efficient antiangiogenesis agents, have been applied in the cancer treatment. However, currently most of these anticancer drugs suffer some adverse effects. Discovery of novel VEGFR2 inhibitors as anticancer drug candidates is still needed.
In this investigation, we adopted a restricted de novo design method to design VEGFR2 inhibitors. We selected the most potent compound SKLB1002 and analyzed its inhibitory effects on human umbilical vein endothelial cells (HUVEC) in vitro. Tumor xenografts in zebrafish and athymic mice were used to examine the in vivo activity of SKLB1002.
The use of the restricted de novo design method indeed led to a new potent VEGFR2 inhibitor, SKLB1002, which could significantly inhibit HUVEC proliferation, migration, invasion, and tube formation. Western blot analysis was conducted, which indicated that SKLB1002 inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including extracellular signal-regulated kinase, focal adhesion kinase, and Src. In vivo zebrafish model experiments showed that SKLB1002 remarkably blocked the formation of intersegmental vessels in zebrafish embryos. It was further found to inhibit a new microvasculature in zebrafish embryos induced by inoculated tumor cells. Finally, compared with the solvent control, administration of 100 mg/kg/d SKLB1002 reached more than 60% inhibition against human tumor xenografts in athymic mice. The antiangiogenic effect was indicated by CD31 immunohistochemical staining and alginate-encapsulated tumor cell assay.
Our findings suggest that SKLB1002 inhibits angiogenesis and may be a potential drug candidate in anticancer therapy.
No preview · Article · May 2011 · Clinical Cancer Research