A Ni-Al bimetallic catalyzed enantioselective C-H exo-selective cyclization of imidazoles with alkenes has been developed. A series of bi- or polycyclic imidazoles with β-stereocenter were obtained in up to 98% yield and >99% ee. The bifunctional SPO ligand-promoted bimetallic catalysis proved to be critical to this challenging stereocontrol.
Supramolecular nanomedicines have shown great merits in cancer therapy, but their clinical translation is hampered by monotonous therapeutic modality and unsatisfactory antitumor performance. Herein, a hybrid supramolecular polymeric nanomedicine (SNPs) is developed based on β‐cyclodextrin/camptothecin (CPT) host−guest molecular recognition and iron‐carboxylate coordination. Iron ions stabilizing SNPs catalyze the conversion of intracellular hydrogen peroxide into highly toxic hydroxyl radical through a Fenton reaction, which further cleaves the thioketal linker of the supramolecular monomer to release potent CPT, thus amplifying the therapeutic efficacy by combining chemodynamic therapy and chemotherapy. The combination therapy stimulates antitumor immunity and promotes intratumoral infiltration of cytotoxic T lymphocytes by triggering immunogenic cell death. In synergy with PD‐L1 checkpoint blockade, SNPs enables enhanced immune therapy and a long‐term tumor remission.
Rationale:
Messenger RNA (mRNA) vaccine outperforms other kinds of cancer immunotherapy due to its high response rates, easy preparation, and wide applicability, which is considered as one of the most promising forms of next-generation cancer therapies. However, the inherent instability and insufficient protein expression duration of mRNA limit the efficacy and widespread application of the vaccine.
Methods:
Here, we first tested the possibility of a novel circular RNA (circRNA) platform for protein expression and compare its duration with linear RNA. Then, we developed a lipid nanoparticle (LNP) system for circRNA delivery
in vitro
and
in vivo
. Next, the innate and adaptive immune response of circRNA-LNP complex was evaluated
in vivo
. The anti-tumor efficacy of circRNA-LNP was further confirmed in three tumor models. Finally, the possibility of combination therapy with circRNA-LNP and adoptive cell transfer therapy was further investigated in a late-stage tumor model.
Results:
We successfully increased the stability of the RNA vaccine by circularizing the linear RNA molecules to form highly stable circRNA molecules which exhibited durable protein expression ability. By encapsulating the antigen-coding circRNA in LNP enabling
in vivo
expression, we established a novel circRNA vaccine platform, which was capable of triggering robust innate and adaptive immune activation and showed superior anti-tumor efficacy in multiple mouse tumor models.
Conclusions:
Overall, our circRNA vaccine platform provides a novel prospect for the development of cancer RNA vaccines in a wide range of hard-to-treat malignancies.
Liposomes and polymersomes, typical vesicular drug delivery systems (DDSs), have faced some limitations in cancer theranostics. Suprasomes, supramolecular vesicles assembled from amphiphiles linked by noncovalent interactions, show potential as new generation of vesicular DDSs. We construct suprasomes based on host-guest recognition, by which the desired functions can be integrated into carriers without tedious synthesis. Photothermally active host-guest complex is formed between a functional guest and pillar[5]arene, which further self-assembles into hollow suprasomes. A supramolecular nanomedicine is developed by encapsulating cisplatin in the suprasomes. The obtained cisplatin@Suprasomes achieve excellent anticancer efficacy and anti-metastasis combining chemotherapy and photothermal therapy, which ablate the tumors without relapse and metastasis. This work demonstrates the facile functionalization of suprasomes, holding promise as alternatives to liposomes and polymersomes.
A carbamoyl fluoride-enabled enantioselective Ni-catalyzed carbocarbamoylation of unactivated alkenes was developed, providing a broad range of chiral γ-lactams bearing an all-carbon quaternary center in 45−96% yield and 38−97% ee.
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