Background Clinical data indicate that a substantial portion of cancer patients, though eligible for immune checkpoint inhibitor (ICI) therapy, cannot fully benefit from ICI monotherapy due to the poor immunogenicity of tumors and lack of tumor-infiltrating lymphocytes within the ‘cold’ tumor microenvironment (TME). In addition to poor antibody penetrance into the TME, systemic delivery of ICIs is associated with immune-related adverse events (irAEs) among recipients, some of which are life-threatening. Oncolytic virotherapy is a potentially viable approach to improving the efficacy of ICI therapy because of their ability to selectively replicate and lyse tumor cells, release tumor-associated antigens (TAAs), induce inflammatory response and promote lymphocyte infiltration in tumors. Methods A recombinant oncolytic adenoviruses (OAd), denoted ZD55-aPD-L1 scFv, which carried the expression cassette for anti-PD-L1 scFv was constructed by molecular cloning. Western blot and ELISA assay were performed to detect aPD-L1 scFv expression. Flow cytometry were used to analyse PD-L1 expression and count tumor cells. Co-culture assay of human peripheral blood mononuclear cells (PBMCs) with tumor cells in vitro and triple-negative breast cancer (TNBC) MDA-MB-231 tumor-bearing model in vivo were evaluated the antitumor effects of recombinant oncolytic adenoviruses ZD55-aPD-L1 scFv. Results We found that cells infected with recombinant oncolytic adenovirus ZD55-aPD-L1 scFv can effectively express aPD-L1 scFv, which function similarly to its full-length anti-PD-L1 antibody. PBMCs have inherently very limited killing effect on tumor cells even with administration of anti-PD-L1 antibody as observed from our in vitro co-cultures. Treatment consisting of ZD55 alone or ZD55 combined with anti-PD-L1 antibody yielded mediocre antitumor efficacy in subsequent in vitro and in vivo investigations, but were all substantially surpassed by the synergistic antitumor effects observed with ZD55-aPD-L1 scFv treatment. We show that the concomitant direct oncolysis by the recombinant OAd and localized autocrine/paracrine interception of PD-1:PD-L1 checkpoint interaction mediated by ZD55-aPD-L1 scFv-infected cells is exceedingly superior to co-administration of ZD55 and anti-PD-L1 antibody in the human TNBC mice model. Conclusions Our results provided evidence for the development of novel strategies, in this case an anti-PD-L1 scFv-armed OAd, to bolster immune responses to ‘cold’ tumors and to improve therapeutic responsiveness to ICIs.
Kong Chenfan,Sun Jianrong,Hu Xinzi,Li Guangzhi,Wu Song
Immune checkpoint inhibitors (ICIs) are effective agents for tumor immunotherapy. However, their clinical effectiveness is unsatisfactory due to off-target effects and a suppressive immune microenvironment. This study developed a nanodrug delivery system for bladder cancer (BCa) using PCL-MPEG and PCL-PEG-CHO to synthesize internal hydrophobic and external hydrophilic micelles (PP) that encapsulated water-insoluble astragaloside IV (PPA). The aldehyde group on the surface of PPA reacted with the amino group of aPD-L1, allowing the decoration of this antibody on the surface of the micelles. The resultingPPA@aPD-L1effectively piggybacked astragaloside IV and aPD-L1 antibody. These findings suggest that PPA@aPD-L1 is relatively stable in circulation and efficiently binds to BCa cells with the aid of aPD-L1. Additionally, this strategy prolongs the drug’s retention time in tumors. Compared to PBS, PP, and PPA with PPA + aPD-L1 groups, PPA@aPD-L1significantly prolonged the survival of mice with BCa and reduced tumor volume. Mechanistic studies showed that PPA inhibited the NF-κB and STAT3 signaling pathways in tumor cells. Additionally, PPA@aPD-L1increased IFN-γ and decreased IL-10 expression in bladder tumors, affecting the number and type of intratumorally infiltrating T cells. Our study presents a simple and effective drug delivery system that combines herbal monomers with ICIs. It has demonstrated a potent ability to suppress tumor growth and holds potential for future applications.
Wentao Wang,Qicheng Zhang,Ming Zhang,Xintong Lv,Zihan Li,Mohsen Mohammadniaei,Ninglin Zhou,Yi Sun
Wound bacterial infections and tumor recurrence are the main reasons for the poor prognosis after primary tumor resection. Here, we fabricated a novel therapeutic nanocomposite using chitosan (CS) hydrogel combined with black phosphate nanosheets (BPNSs) and in situ grown copper nanoparticles (CuNPs). The obtained hydrogel ( [email protected] @CuNPs), possessing a remarkable temperature-sensitive spongy-like state, offered 24.98 % blood clotting index. The released [email protected] could produce reactive oxygen species (ROS) to kill infected invasive bacteria (98.1 %) and inhibit local residual tumor cell regeneration (11.3 %). Moreover, by coupling the photothermal properties of BPNSs , the [email protected] showed 19.6 % penetration rate to cross the blood tumor barrier (BTB) for treating brain tumors. The hydrogel platform was further combined with aPD-L1-based immunotherapy to employ its synergetic therapeutic effect in the prevention of tumors. The in vivo studies showed that biodegradable hydrogel could hold a great potential as a novel strategy for improving postoperative therapy and multi-tumor treatments.
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