Integrating Nanomaterials To Optimize PARP Inhibitor-based Combinatorial Therapy

Objective:For devastating malignancies,the combination of anticancer drugs with different mechanisms is often required to enhance antitumor effects.Previous studies have found that combinations of Poly ADP-ribose polymerase（PARP）inhibitors and WEE1inhibitors/DNA-damaging agents have synergistic tumor suppressive effects.Although these combinations enhance tumor cell killing,they are often accompanied by serious toxic side effects.Nanoparticle encapsulated chemotherapy drugs can effectively reduce toxic side effects and have great potential for development in oncology treatment.Based on the good biocompatibility and high drug loading capacity of mesoporous polydopamine（MPDA）,two nanomedicine therapeutic strategies were constructed in this study:1.Co-loaded PARP inhibitor and WEE1 inhibitor nanomedicine（TPNP-Ada-Ola）-mediated tumor targeting therapy strategy;2.Co-loaded PARP inhibitor and DNA damaging agent nanodrug（O/D@mP）-mediated chemotherapy combined with mild photothermal therapy strategy.Methods:1.TPNP-Ada-Ola mediated tumor-targeting therapy strategy1)Synthesize tumor-targeting peptide TMTP1-modified MPDA nanoparticles（TPNP）,loading of Adavosertib（WEE1 inhibitor）and Olaparib（PARP inhibitor）into TPNP to construct TPNP-Ada-Ola,and examine its physicochemical properties and drug release behavior;2)Immunofluorescence and flow cytometry were developed to assess the tumor-targeting effect of TPNP;3)Study of the tumor-killing effect of TPNP-Ada-Ola in vitro by flow cytometry,immunofluorescence and western blot;4)Examining TPNP-Ada-Ola pharmacokinetics and biodistribution;5)To assess the in vivo tumor suppressive effect and safety of TPNP-Ada-Ola in ovarian cancer cell line xenograft tumor and PDX models.2.O/D@mP-mediated chemotherapy combined with mild photothermal treatment strategy1)Synthesize PEGylated MPDA nanoparticles（mP）,loading olaparib and doxorubicin（DNA damaging agent）into mP to prepare O/D@mP,and assay its physicochemical properties and drug release behavior;2)Flow cytometry were developed to assess the cellular uptake behavior of O/D@mP;3)Exploring the antitumor effect of O/D@mP combined with mild photothermal and the underlying mechanism through MTT,flow cytometry and immunofluorescence experiments;4)Examination of the biodistribution of O/D@mP;5)Evaluation of the tumor suppressive effect in vivo and and safety of O/D@mP in 4T1 subcutaneous tumor model.Results:1.TPNP efficiently encapsulated Adavosertib and Olaparib（TPNP-Ada-Ola）,and realized p H/GSH/H₂O₂-responsive drug release;TPNP actively targeted ovarian cancer cell;TPNP-Ada-Ola promoted tumor cells to enter mitosis prematurely,and had a strong killing effect on tumor cells;The nano-delivery system lengthened drug blood circulation time and showed tumor targeting specificity in both ovarian cancer cell line xenograft tumor and PDX models;TPNP-Ada-Ola significantly inhibited tumor growth and reduced weight loss and liver function impairment caused by the combination of Adavosertib and Olaparib.2.mP efficiently co-loaded Olaparib and Doxorubicin（O/D@mP）with good photothermal conversion performance,and realized p H/NIR-responsive drug release;Tumor cells efficiently uptaked O/D@mP;mP-mediated mild photothermal（≈43°C）significantly downregulated the expression levels of MRE11,RAD51 and BRCA2,key proteins in the homologous recombination pathway,O/D@mP combined with mild photothermal treatment enhanced the toxic effects of the drugs on tumor cells;The nano-delivery system increased drug accumulation in tumor tissues and reduced exposure in normal tissues;O/D@mP-mediated chemotherapy combined with mild photothermal treatment significantly supressed tumor growth and attenuated weight loss,heart and spleen damage induced by Olaparib and Doxorubicin combination therapy.Conclusions:In this study,two nanomedicines,TPNP-Ada-Ola and O/D@mP,were successfully constructed based on MPDA nanoparticles,which effectively attenuated the toxic side effects caused by free drugs combination.Moreover,TPNP-Ada-Ola enhanced the tumor suppressive effect of anticancer drugs by specifically targeting tumors with spatio-temporal controlled release of drugs;O/D@mP-mediated mild photothermal effect augmented the antitumor effect by inhibiting the homologous recombination repair function.This study has provided new insights into the use of combinations of anti-cancer drugs in the treatment of cancer.