A linear polyethylenimine mediated siRNA-based therapy targeting human epidermal growth factor receptor in SPC-A1 xenograft mice.

Yuehong Wang,Chunxue Bai,Xin Zhang,Pinghai Zhang,Zhaochong Zeng,Xin Xu,Ka Li,Nuo Xu,Lei Zhou,Xiangdong Wang

doi:10.1186/2213-0802-1-2

Abstract

BackgroundLinear polyethylenimine (LPEI) is considered as a desirable gene in vivo delivery system, but whether it could deliver the specific siRNA targeted EGFR to the tumor site to inhibit the growth of NSCLC xenograft in nude mice still needs to be examined.MethodsIn this study, LPEI/siRNA was made into a complex and SPC-A1-xenografted mice model was established. Then, stable LPEI/siRNA-EGFR complexes were intraperitoneally administrated. Afterwards, tumor growth was measured every 3 days. At the end of the experiment, tumor volume was calculated, and tumors were weighed, and examined for EGFR expression, proliferation, and apoptosis evaluations. By using blood samples, toxicity tests including aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine (Cr) were measured for liver and renal function evaluation. Serum concentrations of TNF-α and IFN-γ were also examined.ResultsOur results demonstrated that LPEI/siRNA-EGFR complexes could downregulate EGFR expression in SPC-A1 xenografted tumor upon single i.p. injection. LPEI/siRNA-EGFR complexes inhibited tumor growth and did not induce organ toxicity in SPC-A1-xenografted mice. At the end of the experiment no significant IFN-α increase was detected in LPEI/siRNA complexes or glucose-treated groups.ConclusionsThe novel modality of siRNA-based therapy targeting EGFR may be of great potential in NSCLC treatment.Electronic supplementary materialThe online version of this article (doi:10.1186/2213-0802-1-2) contains supplementary material, which is available to authorized users.

Highlights

Linear polyethylenimine (LPEI) is considered as a desirable gene in vivo delivery system, but whether it could deliver the specific siRNA targeted epidermal growth factor receptor (EGFR) to the tumor site to inhibit the growth of Non-small-cell lung cancer (NSCLC) xenograft in nude mice still needs to be examined
LPEI/siRNA-EGFR complexes were prepared at various N/P ratios (= 3, 5, 10, respectively) and their silencing efficiencies were evaluated in the SPC-A1 cell line, previously proven to have a high level of EGFR expression [31]
Under an N/P ratio of 5, 76.42% of down-regulation in EGFR messenger RNA (mRNA) was obtained at 24h after LPEI/siRNA-EGFR transfection (Figure 1A)

Summary

Introduction

Linear polyethylenimine (LPEI) is considered as a desirable gene in vivo delivery system, but whether it could deliver the specific siRNA targeted EGFR to the tumor site to inhibit the growth of NSCLC xenograft in nude mice still needs to be examined. It was discovered to be a process of post-transcriptional gene silencing, which induces degradation of a homologous messenger RNA (mRNA) and protein knock-down in a sequence-specific manner [17,18] Due to this property, siRNA sequences have been designed for many target mRNAs. For example, the target of interest could be a mutated protein, as in the case of NSCLC patients resistant to EGFR-TKIs. conventional small molecule drug discovery involves complicated screening and random modifications, leading to new compounds. To design a therapeutic siRNA requires only knowledge of the target gene’s sequence, and can be chemically synthesized at relatively low cost In this regard, the novel therapeutic modality of siRNA-based gene silencing may have advantages over drugs currently on the market

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