BackgroundBrain metastasis (BM) is one of the principal causes of mortality for lung cancer patients. While the molecular events that govern BM of lung cancer remain frustrating cloudy.MethodsThe miRNA expression profiles are checked in the paired human BM and primary lung cancer tissues. The effect of miR-143-3p on BM of lung cancer cells and its related mechanisms are investigated.ResultsmiR-143-3p is upregulated in the paired BM tissues as compared with that in primary cancer tissues. It can increase the invasion capability of in vitro blood brain barrier (BBB) model and angiogenesis of lung cancer by targeting the three binding sites of 3’UTR of vasohibin-1 (VASH1) to inhibit its expression. Mechanistically, VASH1 can increase the ubiquitylation of VEGFA to trigger the proteasome mediated degradation, further, it can endow the tubulin depolymerization through detyrosination to increase the cell motility. m6A methyltransferase Mettl3 can increase the splicing of precursor miR-143-3p to facilitate its biogenesis. Moreover, miR-143-3p/VASH1 axis acts as adverse prognosis factors for in vivo progression and overall survival (OS) rate of lung cancer.ConclusionsOur work implicates a causal role of the miR-143-3p/VASH1 axis in BM of lung cancers and suggests their critical roles in lung cancer pathogenesis.

Studies on biological functions of N6-methyladenosine (m6A) modification in mRNA have drawn significant attention in recent years. Here we describe the construction and characterization of a CRISPR–Cas13b-based tool for targeted demethylation of specific mRNA. A fusion protein, named dm6ACRISPR, was created by linking a catalytically inactive Type VI-B Cas13 enzyme from Prevotella sp. P5–125 (dPspCas13b) to m6A demethylase AlkB homolog 5 (ALKBH5). dm6ACRISPR specifically demethylates m6A of targeted mRNA such as cytochrome b5 form A (CYB5A) to increase its mRNA stability. It can also demethylate β-catenin-encoding CTNNB1 mRNA that contains multiple m6A sites to trigger its translation. In addition, the dm6ACRISPR system incurs efficient demethylation of targeted epitranscriptome transcripts with limited off-target effects. Targeted demethylation of transcripts coding for oncoproteins such as epidermal growth factor receptor (EGFR) and MYC can suppress proliferation of cancer cells. Together, we provide a programmable and in vivo manipulation tool to study mRNA modification of specific genes and their related biological functions.

Ferroptosis is a programmed cell death pathway discovered in recent years, and ferroptosis‐inducing agents have great potential as new antitumor candidates. Here, we report a IrIII complex (Ir1) containing a ferrocene‐modified diphosphine ligand that localizes in lysosomes. Under the acidic environments of lysosomes, Ir1 can effectively catalyze Fenton‐like reaction, produce hydroxyl radicals, induce lipid peroxidation, down‐regulate glutathione peroxidase 4, and result in ferroptosis. RNA sequencing analysis shows that Ir1 can significantly affect pathways related to ferroptosis and cancer immunity. Accordingly, Ir1 can induce immunogenic cells death and suppress tumor growth in vitro, regulate T cell activity and immune microenvironments in vivo. In conclusion, we show the potential of small molecules with ferroptosis‐inducing capabilities for effective cancer immunotherapy.

An ideal cancer treatment should not only destroy primary tumors but also improve the immunogenicity of the tumor microenvironment to achieve a satisfactory anti‐tumor immune effect. We designed a carbonic anhydrase IX (CAIX)‐anchored rhenium(I) photosensitizer, named CA‐Re, that not only performs type‐I and type‐II photodynamic therapy (PDT) with high efficiency under hypoxia (nanomolar‐level phototoxicity), but also evokes gasdermin D (GSDMD) mediated pyroptotic cell death to effectively stimulate tumor immunogenicity. CA‐Re could disrupt and self‐report the loss of membrane integrity simultaneously. This promoted the maturation and antigen‐presenting ability of dendritic cells (DCs), and fully activated T cells dependent adaptive immune response in vivo, eventually eliminating distant tumors at the same time as destroying primary tumors. To the best of our knowledge, CA‐Re is the first metal complex‐based pyroptosis inducer.

Pyroptosis is a unique form of programmed cell death that is essentially proinflammatory and critical for immunity. In their Research Article(e202115800), Qian Cao, Zong‐Wan Mao, and co‐workers developed a carbonic anhydrase IX (CAIX)‐anchored photosensitizer, CA‐Re, that is capable of inducing and self‐reporting membrane rupture upon irradiation, as well as evoking pyroptosis to activate antitumor immunity. CA‐Re is the first metal‐complex‐based pyroptosis inducer, and this work provides a promising avenue for cancer metalloimmunotherapy.