Liu Zhipeng, Liu Xiufeng, Cao Wenmin, Hua Zi-Chun
The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Nanjing, Jiangsu 210093, China ; State Key Laboratory of Natural Medicines, China Pharmaceutical University Nanjing, Jiangsu 210009, China.
The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Nanjing, Jiangsu 210093, China ; The Stake Key Laboratory of Natural and Biomimetic Drugs, Peking University Beijing 100191, China.
Am J Cancer Res. 2015 Jan 15;5(2):792-801. eCollection 2015.
Activation of receptor tyrosine kinase (RTK) signalling pathways is frequently correlated to cancer cell proliferation, angiogenesis and cell survival. Sprouty (SPRY) proteins function as a physiological endogenous inhibitor of RTK signalling pathways, have been shown to be deregulated in most cancer cells. Here, we demonstrated that over-expression of SPRY1 and SPRY2 inhibited B16F10 cell proliferation through G1 phase arrest in vitro, and SPRY2 showed more potent inhibitory effects than SPRY1. In order to tumor-specific delivery of SPRY1/2 in vivo, two strains of attenuated Salmonella typhimurium VNP20009 (VNP-PQE-SPRY1 and VNP-PQE-SPRY2) were constructed to specifically express SPRY1 or SPRY2 under the control of a hypoxia-induced nirB promoter. The efficiency and specificity of the recombinant strains were validated in both bacteria and animal tumor models. SPRY1 and SPRY2 gene could be specifically driven by the nirB promoter under hypoxia, but not normoxia conditions. In addition, the tumor-targeting ability of VNP-PQE-SPRY1 or VNP-PQE-SPRY2 was similar with VNP. VNP-PQE-SPRY2 significantly suppressed melanoma growth in vivo, suggesting that SPRY2 is a more efficient agent for melanoma therapy. Moreover, the antitumor effect of VNP-SPRY2 is mainly mediated through the inhibition of ERK1/2 phosphorylation, which leads to the inhibition of proliferation in melanoma. Taken together, our results indicated that SPRY2 displayed more potent melanoma suppression than SPRY1 both in vitro and in vivo, and the hypoxia-induced tumor-specific gene therapy of SPRY2 delivered by VNP20009 is a promising strategy for melanoma therapy.
受体酪氨酸激酶（RTK）信号通路的激活常与癌细胞增殖、血管生成和细胞存活相关。Sprouty（SPRY）蛋白作为RTK信号通路的生理性内源性抑制剂，已被证明在大多数癌细胞中失调。在此，我们证明SPRY1和SPRY2的过表达通过体外G1期阻滞抑制B16F10细胞增殖，且SPRY2显示出比SPRY1更强的抑制作用。为了在体内实现SPRY1/2的肿瘤特异性递送，构建了两株减毒鼠伤寒沙门氏菌VNP20009（VNP-PQE-SPRY1和VNP-PQE-SPRY2），以在缺氧诱导的nirB启动子控制下特异性表达SPRY1或SPRY2。重组菌株的效率和特异性在细菌和动物肿瘤模型中均得到验证。SPRY1和SPRY2基因在缺氧而非常氧条件下可由nirB启动子特异性驱动。此外，VNP-PQE-SPRY1或VNP-PQE-SPRY2的肿瘤靶向能力与VNP相似。VNP-PQE-SPRY2在体内显著抑制黑色素瘤生长，表明SPRY2是一种更有效的黑色素瘤治疗药物。此外，VNP-SPRY2的抗肿瘤作用主要通过抑制ERK1/2磷酸化介导，这导致黑色素瘤增殖受到抑制。综上所述，我们的结果表明SPRY2在体外和体内均显示出比SPRY1更强的黑色素瘤抑制作用，并且由VNP20009递送的缺氧诱导的SPRY2肿瘤特异性基因治疗是一种有前景的黑色素瘤治疗策略。
