Glioblastoma (GB) remains the most aggressive primary brain malignancy. Adoptive transfer of chimeric antigen receptor (CAR)-modified immune cells has emerged as a promising anti-cancer approach, yet the potential utility of CAR-engineered natural killer (NK) cells to treat GB has not been explored. Tumors from approximately 50% of GB patients express wild-type EGFR (wtEGFR) and in fewer cases express both wtEGFR and the mutant form EGFRvIII; however, previously reported CAR T cell studies only focus on targeting EGFRvIII. Here we explore whether both wtEGFR and EGFRvIII can be effectively targeted by CAR-redirected NK cells to treat GB. We transduced human NK cell lines NK-92 and NKL and primary NK cells with a lentiviral construct harboring a second generation CAR targeting both wtEGFR and EGFRvIII and evaluated the anti-GB efficacy of EGFR-CAR-modified NK cells. EGFR-CAR-engineered NK cells displayed enhanced cytolytic capability and IFN-γ production when co-cultured with GB cells or patient-derived GB stem cells in an EGFR-dependent manner. In two orthotopic GB xenograft mouse models, intracranial administration of NK-92-EGFR-CAR cells resulted in efficient suppression of tumor growth and significantly prolonged the tumor-bearing mice survival. These findings support intracranial administration of NK-92-EGFR-CAR cells represents a promising clinical strategy to treat GB.

Multidrug resistance is a major challenge to cancer chemotherapy. The multidrug resistance phenotype is associated with the overexpression of the adenosine triphosphate (ATP)-driven transmembrane efflux pumps in cancer cells. Here, we report a lipid membrane-coated silica-carbon (LSC) hybrid nanoparticle that targets mitochondria through pyruvate, to specifically produce reactive oxygen species (ROS) in mitochondria under near-infrared (NIR) laser irradiation. The ROS can oxidize the NADH into NAD ⁺ to reduce the amount of ATP available for the efflux pumps. The treatment with LSC nanoparticles and NIR laser irradiation also reduces the expression and increases the intracellular distribution of the efflux pumps. Consequently, multidrug-resistant cancer cells lose their multidrug resistance capability for at least 5 days, creating a therapeutic window for chemotherapy. Our in vivo data show that the drug-laden LSC nanoparticles in combination with NIR laser treatment can effectively inhibit the growth of multidrug-resistant tumors with no evident systemic toxicity.

A combinational therapy of EGFR-CAR NK cells and oncolytic herpes simplex virus 1 for breast cancer brain metastases A combinational therapy of EGFR-CAR NK cells and oncolytic herpes simplex virus 1 for breast cancer brain metastases

Genomic deletion of the tumour suppressor TP53 frequently includes other neighbouring genes, such as the POLR2A housekeeping gene that encodes a crucial RNA polymerase II subunit; suppression of POLR2A with α-amanitin or by RNA interference selectively inhibits the tumorigenic potential of cancer cells, and in mouse models of cancer, tumours can be selectively targeted with α-amanitin coupled to antibodies, suggesting new therapeutic approaches for human cancers. The tumour suppressor gene TP53 is inactivated by mutation or deletion in a majority of human tumours. So far, attempts to restore the activity of its product, p53, have had little success owing to the complexity of p53 signalling. This paper suggests a new approach to targeting TP53 indirectly. Genomic deletion of TP53 frequently includes other neighbouring genes, such as the POLR2A housekeeping gene that encodes a crucial RNA polymerase II subunit. Xionbin Lu and colleagues show that loss of one copy of POLR2A renders cancer cells highly sensitive to inhibitors of RNA polymerase II, such as α-amanitin. In mouse models of cancer, tumours containing the POLR2A/TP53 co-deletion can be selectively targeted with α-amanitin conjugated to antibodies that target the cancer cells. Exploiting similar selective vulnerabilies for other genomic deletions that affect essential housekeeping in addition to tumour suppressor genes may pave a way towards selective therapies for a broad range of cancers. TP53, a well-known tumour suppressor gene that encodes p53, is frequently inactivated by mutation or deletion in most human tumours1,2. A tremendous effort has been made to restore p53 activity in cancer therapies3,4,5,6,7. However, no effective p53-based therapy has been successfully translated into clinical cancer treatment owing to the complexity of p53 signalling. Here we demonstrate that genomic deletion of TP53 frequently encompasses essential neighbouring genes, rendering cancer cells with hemizygous TP53 deletion vulnerable to further suppression of such genes. POLR2A is identified as such a gene that is almost always co-deleted with TP53 in human cancers. It encodes the largest and catalytic subunit of the RNA polymerase II complex, which is specifically inhibited by α-amanitin8,9. Our analysis of The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) databases reveals that POLR2A expression levels are tightly correlated with its gene copy numbers in human colorectal cancer. Suppression of POLR2A with α-amanitin or small interfering RNAs selectively inhibits the proliferation, survival and tumorigenic potential of colorectal cancer cells with hemizygous TP53 loss in a p53-independent manner. Previous clinical applications of α-amanitin have been limited owing to its liver toxicity10. However, we found that α-amanitin-based antibody–drug conjugates are highly effective therapeutic agents with reduced toxicity11. Here we show that low doses of α-amanitin-conjugated anti-epithelial cell adhesion molecule (EpCAM) antibody lead to complete tumour regression in mouse models of human colorectal cancer with hemizygous deletion of POLR2A. We anticipate that inhibiting POLR2A will be a new therapeutic approach for human cancers containing such common genomic alterations.