title: Intratumoral expression of mature human neutrophil peptide-1 potentiates the therapeutic effect of doxorubicin in a mouse 4T1 breast cancer model.
abstract: 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.
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Qin
authors.affiliation: Department of Endocrine Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing, P.R. China.
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Hua-Shan
authors.initials: HS
authors.lastname: Shi
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Luo
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Fu-Chun
authors.initials: FC
authors.lastname: Guo
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Wang
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001692:Biological Transport; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D003131:Combined Modality Therapy; D004317:Doxorubicin / Q000378:metabolism / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D005260:Female; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000517:prevention & control / Q000556:secondary; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D053078:Membrane Potential, Mitochondrial; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D023041:Xenograft Model Antitumor Assays; D023084:alpha-Defensins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000903:Antibiotics, Antineoplastic; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; D004317:Doxorubicin; D002945:Cisplatin