Direct CD32 T-cell cytotoxicity: implications for breast cancer prognosis and treatment.

The FcγRII (CD32) ligands are IgFc fragments and pentraxins. The existence of additional ligands is unknown. We engineered T cells with human chimeric receptors resulting from the fusion between CD32 extracellular portion and transmembrane CD8α linked to CD28/ζ chain intracellular moiety (CD32-CR). Transduced T cells recognized three breast cancer (BC) and one colon cancer cell line among 15 tested in the absence of targeting antibodies. Sensitive BC cell conjugation with CD32-CR T cells induced CD32 polarization and down-regulation, CD107a release, mutual elimination, and proinflammatory cytokine production unaffected by human IgGs but enhanced by cetuximab. CD32-CR T cells protected immunodeficient mice from subcutaneous growth of MDA-MB-468 BC cells. RNAseq analysis identified a 42 gene fingerprint predicting BC cell sensitivity and favorable outcomes in advanced BC. ICAM1 was a major regulator of CD32-CR T cell-mediated cytotoxicity. CD32-CR T cells may help identify cell surface CD32 ligand(s) and novel prognostically relevant transcriptomic signatures and develop innovative BC treatments.

ADAR2/miR-589-3p axis controls glioblastoma cell migration/invasion.

Recent studies have reported the emerging role of microRNAs (miRNAs) in human cancers. We systematically characterized miRNA expression and editing in the human brain, which displays the highest number of A-to-I RNA editing sites among human tissues, and in de novo glioblastoma brain cancer. We identified 299 miRNAs altered in their expression and 24 miRNAs differently edited in human brain compared to glioblastoma tissues. We focused on the editing site within the miR-589-3p seed. MiR-589-3p is a unique miRNA almost fully edited (∼100%) in normal brain and with a consistent editing decrease in glioblastoma. The edited version of miR-589-3p inhibits glioblastoma cell proliferation, migration and invasion, while the unedited version boosts cell proliferation and motility/invasion, thus being a potential cancer-promoting factor. We demonstrated that the editing of this miRNA is mediated by ADAR2, and retargets miR-589-3p from the tumor-suppressor PCDH9 to ADAM12, which codes for the metalloproteinase 12 promoting glioblastoma invasion. Overall, our study dissects the role of a unique brain-specific editing site within miR-589-3p, with important anticancer features, and highlights the importance of RNA editing as an essential player not only for diversifying the genomic message but also for correcting not-tolerable/critical genomic coding sites.