Li Dan, Qin Qing, Wang Xiao-Yi, Shi Hua-Shan, Luo Min, Guo Fu-Chun, Wang Wei, Wang Yong-Sheng
Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
Department of Endocrine Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing, P.R. China.
Oncol Rep. 2014 Mar;31(3):1287-95. doi: 10.3892/or.2013.2947. Epub 2013 Dec 30.
Human neutrophil peptides (HNPs) 1-3 possess a high degree of similarity and are deregulated in many types of human tumors. Previous studies have demonstrated that tumor cell lines and microdissected fresh tumor cells express HNP1-3. In vitro, HNP1-3 have been reported to be cytotoxic to various types of tumor cells. Previously, we observed that the intracellular expression of HNP1 increased plasma membrane permeability in A549 cells and inhibited in vivo tumor angiogenesis. Based on these findings, we inferred that the intratumoral expression of HNP1 may benefit chemotherapy in solid tumors. In the present study, we established a mouse 4T1 breast cancer model imitating locally advanced breast cancer (LABC) and we injected the mice intratumorally with plasmid HNP1 (pHNP1). Doxorubicin (Dox) was administered twice i.v. at 5 mg/kg body weight on day 1 and 8. The possible mechanisms were investigated by evaluating cell proliferation and apoptosis, intracellular Dox accumulation, mitochondrial transmembrane potential (ΔΨm) and ultrastructural alteration of intratumoral microvessels. Compared with the single agent treatment, the combination of Dox and pHNP1 resulted in a significant delay in in vivo tumor growth and a decrease in lung metastasis. This chemosensitization effect was also observed in an A549 lung cancer model treated with cisplatin (DDP) and pHNP1. MTT assay and Annexin V staining demonstrated that 4T1 cells pre-transfected with pHNP1 were significantly more sensitive to Dox, causing increased proliferation inhibition and apoptosis. Further investigations showed that the intracellular expression of HNP1 enhanced Dox accumulation and significantly impaired mitochondrial ΔΨm. Moreover, in tumor tissues, HNP1 mediated intratumoral microvessel normalization and caused significant in situ tumor cell apoptosis. Our study suggests that intratumoral expression of HNP1 can significantly improve the therapeutic efficacy of Dox in breast cancer, abrogate the influence of multidrug resistance and enhance medication safety. Our findings may be important for the clinical therapeutic strategies of cancer chemotherapy.
人中性粒细胞肽（HNPs）1 - 3具有高度相似性，且在多种人类肿瘤中表达失调。先前的研究表明，肿瘤细胞系和经显微切割的新鲜肿瘤细胞表达HNP1 - 3。在体外，据报道HNP1 - 3对多种类型的肿瘤细胞具有细胞毒性。此前，我们观察到HNP1的细胞内表达增加了A549细胞的质膜通透性，并抑制了体内肿瘤血管生成。基于这些发现，我们推测HNP1在肿瘤内的表达可能有益于实体瘤的化疗。在本研究中，我们建立了一个模拟局部晚期乳腺癌（LABC）的小鼠4T1乳腺癌模型，并向小鼠肿瘤内注射质粒HNP1（pHNP1）。阿霉素（Dox）在第1天和第8天以5 mg/kg体重静脉注射两次。通过评估细胞增殖和凋亡、细胞内Dox积累、线粒体跨膜电位（ΔΨm）以及肿瘤内微血管的超微结构改变来研究可能的机制。与单药治疗相比，Dox和pHNP1联合使用导致体内肿瘤生长显著延迟，肺转移减少。在用顺铂（DDP）和pHNP1治疗的A549肺癌模型中也观察到了这种化学增敏作用。MTT试验和膜联蛋白V染色表明，预先用pHNP1转染的4T1细胞对Dox明显更敏感，导致增殖抑制和凋亡增加。进一步研究表明，HNP1的细胞内表达增强了Dox积累，并显著损害线粒体ΔΨm。此外，在肿瘤组织中，HNP1介导肿瘤内微血管正常化，并导致显著的原位肿瘤细胞凋亡。我们的研究表明，HNP1在肿瘤内的表达可显著提高Dox对乳腺癌的治疗效果，消除多药耐药的影响并提高用药安全性。我们的发现可能对癌症化疗的临床治疗策略具有重要意义。
