Targeted inhibition of protein synthesis renders cancer cells vulnerable to apoptosis by unfolded protein response

Orchestrating apoptosis and ferroptosis through enhanced sonodynamic therapy using amorphous UIO-66-CoOx

The development of efficient and multifunctional sonosensitizers is crucial for enhancing the efficacy of sonodynamic therapy (SDT). Herein, we have successfully constructed a CoOx-loaded amorphous metal-organic framework (MOF) UIO-66 (A-UIO-66-CoOx) sonosensitizer with excellent catalase (CAT)- and glutathione-oxidase (GSH-OXD)-like activities. The A-UIO-66-CoOx exhibits a 2.6-fold increase in singlet oxygen (1O2) generation under ultrasound (US) exposure compared to crystalline UIO-66 sonosensitizer, which is attributed to its superior charge transfer efficiency and consistent oxygen (O2) supply. Additionally, the A-UIO-66-CoOx composite reduces the expression of glutathione peroxidase (GPX4) by depleting glutathione (GSH) through Co3+ and Co2+ valence changes. The high levels of highly cytotoxic 1O2 and deactivation of GPX4 can lead to lethal lipid peroxidation, resulting in concurrent apoptosis and ferroptosis. Both in vitro and vivo tumor models comprehensively confirmed the enhanced SDT antitumor effect using A-UIO-66-CoOx sonosensitizer. Overall, this study emphasizes the possibility of utilizing amorphization engineering to improve the effectiveness of MOFs-based sonosensitizers for combined cancer therapies.

Ascomylactam C Induces an Immunogenic Cell Death Signature via Mitochondria-Associated ER Stress in Lung Cancer and Melanoma

Ascomylactam C (AsC) is a new 13-membered-ring macrocyclic alkaloid, which was first isolated and identified in 2019 from the secondary metabolites of the mangrove endophytic fungus Didymella sp. CYSK-4 in the South China Sea. AsC has been found to have a broad-spectrum cytotoxic activity. However, the antitumor effects in vivo and mechanisms of AsC remain unclear. The aim of this study was to describe the effects of AsC on lung cancer and melanoma cells and to explore the antitumor molecular mechanism of AsC. In vitro, we used plate colony formation experiments and demonstrated the ability of AsC to inhibit low-density tumor growth. An Annexin V/PI cell apoptosis detection experiment revealed that AsC induced tumor cell apoptosis. In vivo, AsC suppressed the tumor growth of LLC and B16F10 allograft significantly in mice, and promoted the infiltration of CD4+ T and CD8+ T cells in tumor tissues. Mechanistically, by analyses of Western blotting, immunofluorescence and ELISA analysis, we found that AsC increased ROS formation, induced endoplasmic reticulum (ER) stress, activated the protein kinase RNA-like ER kinase (PERK)/eukaryotic translation initiation factor (eIF2α)/activating transcription factor 4 (ATF4)/C/EBP homologous protein (CHOP) signaling pathway, and induced immunogenic cell death (ICD) of tumor cells. Our results suggest that AsC may be a potentially promising antitumor drug candidate.