Reversing ferroptosis resistance by MOFs through regulation intracellular redox homeostasis

As a non-apoptotic cell death form,ferroptosis offers an alternative approach to overcome cancer chemotherapy resistance.However,accumulating evidence indicates cancer cells can develop ferroptosis resistance by evolving antioxidative defense mechanisms.To address this issue,we prepared a Buthionine-(S,R)-sulfoximine(BSO)loaded metal organic framework(MOF)of BSO-MOF-HA(BMH)with the combination effect of boosting oxidative damage and inhibiting antioxidative defense.MOF nanoparticle was constructed by the photosensitizer of[4,4,4,4-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid)](TCPP)and the metal ion of Zr6,which was further decorated with hyaluronic acid(HA)in order to impart active targeting to CD44 receptors overexpressed cancer cells.BMH exhibited a negative charge and spherical shape with average particle size about 162.5nm.BMH was found to restore the susceptibility of 4T1 cells to ferroptosis under irradiation.This was attributed to the combination of photodynamic therapy(PDT)andγ-glutamylcysteine synthetase inhibitor of BSO,shifting the redox balance to oxidative stress.Enhanced ferroptosis also induced the release of damage associated molecular patterns(DAMPs)to maturate dendritic cells and activated T lymphocytes,leading to superior anti-tumor performance in vivo.Taken together,our findings demonstrated that boosting oxidative damage with photosensitizer serves as an effective strategy to reverse ferroptosis resistance.

Preparation and evaluation of poly(L-histidine) based pH-sensitive micelles for intracellular delivery of doxorubicin against MCF-7/ADR cells

In this study, a p H-sensitive micelle self-assembled from poly(L-histidine) based triblock copolymers of poly(ethylene glycol)–poly(D,L-lactide)–poly(L-histidine)(mPEG-PLA-PHis) was prepared and used as the intracellular doxorubicin(Dox) delivery for cancer chemotherapy. Dox was loaded into the micelles by thin-film hydration method and a Box–Behnken design for three factors at three levels was used to optimize the preparations. The optimized mPEG-PLA-Phis/Dox micelles exhibited good encapsulation efficiency of 91.12%,a mean diameter of 45 nm and narrow size distribution with polydispersity index of 0.256.In vitro drug release studies demonstrated that Dox was released from the micelles in a p Hdependent manner. Furthermore, the cellular evaluation of Dox loaded micelles displayed that the micelles possessed high antitumor activity in vitro with an IC50 of 35.30 μg/ml against MCF-7/ADR cells. The confocal microscopy and flow cytometry experiments indicated that m PEG-PLA-Phis micelles mediated efficient cytoplasmic delivery of Dox with the aid of poly(Lhistidine) mediated endosomal escape. In addition, blank m PEG-PLA-Phis micelles were shown to be nontoxic to MCF-7/ADR cells even at a high concentration of 200 μg/ml. The pHsensitive mPEG-PLA-PHis micelles have been demonstrated to be a promising nanosystem for the intracellular delivery of Dox for MDR reversal.

Co-delivery of resveratrol and docetaxel via polymeric micelles to improve the treatment of drug-resistant tumors

Co-delivery of anti-cancer drugs is promising to improve the efficacy of cancer treatment.This study was aiming to investigate the potential of concurrent delivery of resveratrol(RES)and docetaxel(DTX)via polymeric nanocarriers to treat breast cancer.To this end,methoxyl poly(ethylene glycol)-poly(D,L-lactide)copolymer(mPEG-PDLA)was prepared and characterized using FTIR and 1H NMR,and their molecular weights were determined by GPC.Isobologram analysis and combination index calculation were performed to find the optimal ratio between RES and DTX to against human breast adenocarcinoma cell line(MCF-7 cells).Subsequently,RES and DTX were loaded in the mPEG-PDLA micelles simultaneously,and the morphology,particle size distribution,in vitro release,pharmacokinetic profiles,as well as cytotoxicity to the MCF-7 cells were characterized.IC50 of RES and DTX in MCF-7 cells were determined to be 23.0μg/ml and 10.4μg/ml,respectively,while a lower IC50 of 4.8μg/ml of the combination of RES and DTX was obtained.The combination of RES and DTX at a ratio of 1:1(w/w)generated stronger synergistic effect than other ratios in the MCF-7 cells.RES and DTX loaded mPEG-PDLA micelles exhibited prolonged release profiles,and enhanced cytotoxicity in vitro against MCF-7 cells.The AUC(0→t)of DTX and RES in mPEG-PDLA micelles after i.v.administration to rats were 3.0-fold and 1.6-fold higher than that of i.v.injections of the individual drugs.These findings indicated that the co-delivery of RES and DTX using mPEG-PDLA micelles could have better treatment of tumors.

Effect of surface ligand density on cytotoxicity and pharmacokinetic profile of docetaxel loaded liposomes

Various biotin-modified liposomes incorporated with docetaxel(DTX) were prepared to study the effect of surface biotin density on the pharmacokinetic profile of the liposome. Four types of liposomes such as PEG modified liposome(PDL), 0.5%(mol) biotin modified liposome(0.5 BDL), 1%(mol) biotin modified liposome(1 BDL) and 2%(mol) biotin modified liposome(2 BDL) were prepared using thin film dispersion method. The prepared liposomes were characterized by measuring encapsulation efficiency(EE), particle size, Zeta-potential, physical stability and drug release profiles in vitro. MTT assay was performed to elevate the cytotoxicity of liposomes on MCF-7 cells. In vivo evaluation was further performed to investigate the effect of biotin surface density on the pharmacokinetic profiles. All the prepared liposomes exhibited high encapsulation efficiency, small particle size, narrow particle distribution and sustained release profiles in vitro. In MTT assay, 0.5 BDL showed largest tumor cell toxicity, compared with DTX solution. All liposomes containing DTX showed prolonged blood circulation in vivo, and 0.5 BDL showed the longest circulation time among the biotin modified liposome. Surface modification of liposome had a negative impact on the circulation of liposomes in the blood, which needs to be considered when designing the ligand mediated targeting delivery systems. A proper amount of biotin liposome with 0.5% molar ratio is expected to produce the best anti-tumor effect.

Combining immune checkpoint blockade with ATP-based immunogenic cell death amplifier for cancer chemo-immunotherapy

Amplifying“eat me signal”during tumor immunogenic cell death(ICD)cascade is crucial for tumor immunotherapy.Inspired by the indispensable role of adenosine triphosphate(ATP,a necessary“eat me signal”for ICD),a versatile ICD amplifier was developed for chemotherapy-sensitized immunotherapy.Doxorubicin(DOX),ATP and ferrous ions(Fe^(2+))were co-assembled into nanosized amplifier(ADO-Fe)throughπ‒πstacking and coordination effect.Meanwhile,phenylboric acid-polyethylene glycol-phenylboric acid(PBA-PEG-PBA)was modified on the surface of ADO-Fe(denoted as PADO-Fe)by the virtue of d-ribose unit of ATP.PADO-Fe could display active targetability against tumor cells via sialic acid/PBA interaction.In acidic microenvironment,PBA-PEG-PBA would dissociate from amplifier.Moreover,high H_(2)O_(2)concentration would induce hydroxyl radical(·OH)and oxygen(O_(2))generation through Fenton reaction by Fe^(2+).DOX and ATP would be released from the amplifier,which could induce ICD effect and“ICD adjuvant”to amplify this process.Together with programmed death ligands 1(PD-L1)checkpoint blockade immunotherapy,PADO-Fe could not only activate immune response against primary tumor,but also strong abscopal effect against distant tumor.Our simple and multifunctional ICD amplifier opens a new window for enhancing ICD effect and immune checkpoint blockade therapy.