Preparation And The Antitumor Efficacy Assessment Of The Quadrivalent Cisplatin Nanoparticles Targeting Copper Transport

Background:Copper is an essential transition metal facilitating variousbiological processes and is increasingly implicated in tumor proliferation,angiogenesis,and metastasis.Recent progress in studying copper-dependent targets and pathways in the context of tumor treatment has forged new insights into therapeutic strategies of leveraging copper-dependent disease vulnerabilities and pharmacologically manipulation of intratumor copper transport to improve the benefits of chemotherapy.Objective:To figure out the role that copper chaperone Atox1 playedduring the platinum-based chemotherapeutic process of non-small cell lung cancer（NSCLC）and the value of Atox1 as a potential therapeutic target.To develop an efficient and safe nano-delivery system for facilitating the synergistic antitumor efficacy of copper chaperone inhibitor and cisplatin,and provide a novel insight for enhanced tumor immunochemotherapy.Methods:First of all,cohorts of 884 NSCLC patients from the TCGA database were assessed by both overall survival and progression-free survival,as patients were stratified according to RNA levels of Atox1within their tumors,as well as according to whether or not they were treated with platinum agents.And the synergistic antitumor efficacy of Atox1 inhibitor DC＿AC50 and cisplatin were also investigated in various cell lines.Secondly,an oxidation-responsive nanoparticle（NP2）was fabricated by nanoprecipitation of quadrivalent cisplatin prodrug cisplatin（IV）（Cis Pt（IV））with DC＿AC50 conjugated to the polymers.The morphology,particle size,and polydispersity index were carefully assessed by transmission electron microscopy and dynamic light scattering.We also evaluated the oxidation-responsive release behavior of NP2 by dialysis technique.Next,the capacity of NP2 in sensitizing cisplatin-based chemotherapy and inducing immunogenic cell death were explored in various NSCLC cell lines.Finally,the biodistribution and tumor retention efficacy of NP2 were detected with an In Vivo Imaging system in the syngeneic subcutaneous LLC tumor-bearing mouse model.And the immune-activation characteristics and chemo-sensitization effects of NP2were further investigated in vivo.Results:（1）The expression of Atox1 were negatively correlated with thesurvival of cisplatin-treated NSCLC patients（P=0.042）,while the expression of Atox1 did not exhibit any obvious associations with survival of lung cancer patients who received other types of therapy rather than platinum agents（P=0.84）.（2）DC＿AC50 could promote a substantial accumulation of intracellular cisplatin and exhibit a synergistic antitumor efficacy with cisplatin(CI₅₀=0.494).The application of nano-delivery system further facilitated the cellular uptake of drugs and strengthened the synergy effect of DC＿AC50 and cisplatin(CI₅₀=0.143).（3）NP2 exhibited a uniform spherical shape with a homogenous diameter around 115 nm and could release in response to the oxidative environment.The excellent tumor accumulation and retention efficacy of NP2 were also observed in the subcutaneous LLC tumor-bearing mice.（4）NP2 could not only enhance the cisplatin-based chemotherapy,but also promote the generation of intracellular reactive oxygen species which led to ER stress,thereby inducing immunogenic cell death and the release of various damage-associated molecular patterns.（5）NP2 exhibited excellent tumor-suppressive effects in the subcutaneous LLC tumor-bearing mice.More importantly,the immunogenic cell death induced by NP2 further increased the maturation and cross-presentation of dendritic cells,thereby increasing the frequencies of cytotoxic T lymphocytes and nature killer cells,decreasing the infiltration of regulatory T cells in the tumors,and promoting the establishment of long-term immunologic memory.Conclusion:Copper chaperones could function as potential targets forcombination with platinum-based chemotherapy.Co-administration of copper chaperone inhibitor DC＿AC50 and quadrivalent cisplatin with nano-delivery system could not only significantly potentiate the efficacy of cisplatin,but also induce immunogenic death of tumor cells and activate the antitumor immunity.This study has provided a promising therapeutic strategy for enhancement of the efficacy of platinum-based chemotherapy.