Enantiomerization of five-membered-heterocycle-embedded helicenes: A DFT study.

In this work, DFT theoretical calculations were employed to investigate the enantiomerization of helicenes embedded with five-membered heterocycles. The original benzene rings in the helicene backbone were replaced by heterocycles such as furan, thiophene, pyrrole, or phosphole to create [n]helicenes with n ranging from 4 to 7. The impact of the type, position, and number of heterocycles on the enantiomerization barrier was systematically evaluated. Notably, the enantiomerization barrier was found to be significantly dependent on the rotatory angle and the position of the heterocycles, particularly for [4, 5]helicenes. With less rotatory angle of heterocycle, the enantiomerization barrier of helicenes was revealed to be lower, while when the heterocycle was close to the central part of the helicene chain, the barrier was also lower. Furthermore, the number of thiophene rings also had a marked effect on enantiomerization, showing a decrease of the barrier with more thiophene rings placed on the helicenes backbone. We expect this work would deliver new perspective on the relative studies for the helicene conformational conversion.

A Universal Cyclodextrin-Based Nanovaccine Platform Delivers Epitope Peptides for Enhanced Antitumor Immunity.

Currently, there is still an intense demand for a simple and scalable delivery platform for peptide-based cancer vaccines. Herein, a cyclodextrin-based polymer nanovaccine platform (CDNP) is designed for the codelivery of peptides with two immune adjuvants [the Toll-like receptor (TLR)7/8 agonist R848 and the TLR9 agonist CpG] that is broadly applicable to epitope peptides with diverse sequences. Specifically, the cyclodextrin-based polymers are covalently linked to epitope peptides via a bioreactive bond-containing cross-linker (PNC-DTDE-PNC) and then physically load with R848 and CpG to obtain CDNP. The CDNP efficiently accumulats in the lymph nodes (LNs), greatly facilitating antigen capture and cross-presentation by antigen-presenting cells. The immunogenicity of the epitope peptides is significantly enhanced by the codelivery and synergy of the adjuvants, and the CDNP shows the ability to inhibit tumor progression in diverse tumor-bearing mouse models. It is concluded that CDNP holds promise as an optimized peptide-based cancer vaccine platform.

Co-delivery of proanthocyanidin and mitoxantrone induces synergistic immunogenic cell death to potentiate cancer immunotherapy.

Immunological checkpoint inhibitors provide a revolutionary method for cancer treatment. However, due to low tumor mutations and insufficient infiltration of immune cells into the tumor microenvironment, 85% of colorectal cancer patients cannot respond to checkpoint blockade immunotherapy. In this study, tumor microenvironment-responsive deformable nanoparticles (DMP@NPs) were rationally designed to improve immunotherapy by synergistically modulating the immune tumor microenvironment. DMP@NPs self-assemble from a newly synthesized tumor acidity responsive polypeptide checkpoint inhibitor polymer (PEG-DMA-DPPA-1) with immunogenic cell death (ICD) enhanced combination drugs containing a certain proportion of mitoxantrone (MITX) and proanthocyanidins (PC). Upon tumor acidity-triggered cleavage of PEG-DMA-DPPA-1, DMP@NPs undergo special "sphere-ring deformation" dissociation, gradually releasing polypeptide checkpoint inhibitor DPPA-1, MITX and PC. MITX/PC in vitro synergistically triggers higher ICD with the release of the high mobility group box-1 (HMGB-1) and calreticulin (CRT). After intravenous injection of DMP@NPs, the local tumor microenvironment of CT26 tumor-bearing mice was reprogrammed, and dendritic cell activation and T cell infiltration were significantly increased. Most importantly, the synergistic immune nanodrug DMP@NPs improved the efficacy of colorectal cancer immunotherapy and reduced toxicity and side effects for the immune organs.