Efficient inhibition of lung cancer in murine model by plasmid-encoding VEGF short hairpin RNA in combination with low-dose DDP

Abstract

BackgroundVEGF is a well-validated target for antiangiogenic intervention in cancer. To date, RNAi technology has been proven to be a promising approach for targeted therapy. DDP is frequently used as a first-line drug in chemotherapy for lung cancer but usually causes severe toxicity. In this study, we investigated a novel strategy of administering and combining RNAi mediated VEGF-targeted therapy with DDP for treatment of lung cancer, with the aim of increasing efficacy and decreasing toxicity.MethodsIn this study, a plasmid encoding VEGF shRNA was constructed to knockdown VEGF both in vitro and in vivo. In vitro, specificity and potency of the targeting sequence were validated in A549 lung adenocarcinoma cells by RT-PCR and ELISA assays. In vivo, therapy experiments were conducted on nude mice bearing A549 xenograft tumors. The VEGF shRNA expressing plasmids were administered systemically in combination with low-dose DDP on a frequent basis. The tumor volume and weight were measured. MVD, the number of apoptotic cells and proliferation index in tumor tissues were assessed by CD31, TUNEL and PCNA immunostaining.ResultsThe VEGF shRNA was highly effective in attenuating VEGF expression both in vitro and in vivo. The treatment with the VEGF shRNA alone reduced the mean tumor weight by 49.40% compared with the blank control (P < 0.05). The treatment with the VEGF shRNA plus DDP yielded maximal benefits by reducing the mean tumor weight by 83.13% compared with the blank control (P < 0.01). The enhanced antitumor efficacy was associated with decreased angiogenesis and increased induction of apoptosis.ConclusionsOur study demonstrated synergistic antitumor activity of combined VEGF shRNA expressing plasmids and low-dose DDP with no overt toxicity, suggesting potential applications of the combined approach in the treatment of lung cancer.

Efficient Inhibition of Human Colorectal Carcinoma Growth by RNA Interference Targeting Polo-Like Kinase 1 In Vitro and In Vivo

“…We got an apparent effect by using RNAi to reduce PLK1 expression of the tumor cells in vitro and in vivo. According to the previous study in our lab, 29 intravenous administration of plasmids were given every 2 days at a dose of 5 lg per mouse, and the strictly executed dose/scheduled strategy attained good treatment effectiveness without severe toxicities.…”

“…The cationic liposome was prepared in our lab using the procedure previously described. 29 Five (5) lg Plasmid DNA and 25 lg cationic liposome were complexed gently in 100 lL of 5% glucose, then the complex was injected into the mouse tail vein thrice a week for totally ten times. Tumor diameters were measured every 2 days during the treatment period.…”

Combination of capecitabine and ludartin inhibits colon cancer growth in mice

“…VEGF plays an important role in the progression of tumour angiogenesis; its expression is a characteristic of angiogenesis [16,17]. Studies have shown that higher expression of VEGF in tumor cells is associated with the development of drug resistance [18][19][20].…”

Influence of Stromal Components on Lung Cancer Carcinogenesis

“…Therefore, studies using conditional knockdown of VEGF expression in tissues or tumor cells or blocking VEGF receptors have shown the role VEGF plays in primary tumor growth and metastasis. Ma and colleagues used shRNA targeting VEGF in A549 lung adenocarcinoma cells to show that decreased VEGF expression in tumor cells resulted in decreased tumor growth and results were more profound when the chemotherapy agent, cis-Diclorodiamminoplatino (DDP), was administered concomitantly [23]. The VEGF pathway is the focus of many treatment strategies currently in preclinical and clinical development.…”