Glioblastoma multiforme (GBM) is an aggressive primary brain tumor, for which there is no cure. Treatment effectiveness for GBM has been limited due to tumor heterogeneity, an immunosuppressive tumor microenvironment (TME) and the presence of the blood brain barrier, which hampers the transport of chemotherapeutic compounds to the central nervous system (CNS). High-density lipoprotein (HDL)-mimicking nanodiscs hold considerable promise to achieve delivery of bioactive compounds into tumors. Herein, we tested the ability of synthetic HDL nanodiscs, to deliver chemotherapeutic agents to the GBM microenvironment and elicit tumor regression. To this end, we developed chemo-immunotherapy delivery vehicles based on sHDL nanodiscs loaded with CpG, a Toll-like receptor 9 (TLR9) agonist, together with docetaxel (DTX), a chemotherapeutic agent, for targeting GBM. Our data show that delivery of DTX-sHDL-CpG nanodiscs into the tumor mass elicited tumor regression and anti-tumor CD8+ T cell responses in the brain TME. We did not observe any overt off-target side effects. Furthermore, the combination of DTX-sHDL-CpG treatment with radiation (IR), which is the standard of care for GBM, resulted in tumor regression and long-term survival in 80% of GBM-bearing animals. Mice remained tumor free upon tumor cell rechallenge in the contralateral hemisphere, indicating the development of anti-GBM immunological memory. Collectively, these data indicate that sHDL nanodiscs constitute an effective drug delivery platform for the treatment of GBM, resulting in tumor regression, long term survival and immunological memory, when used in combination with IR. The proposed delivery platform has significant potential for clinical translation.

Research into the immunological processes implicated in cancer has yielded a basis for the range of immunotherapies that are now considered the fourth pillar of cancer treatment (alongside surgery, radiotherapy and chemotherapy). For some aggressive cancers, such as advanced non-small-cell lung carcinoma, combination immunotherapies have resulted in unprecedented treatment efficacy for responding patients, and have become frontline therapies. Individualized immunotherapy, enabled by the identification of patient-specific mutations, neoantigens and biomarkers, and facilitated by advances in genomics and proteomics, promises to broaden the responder patient population. In this Perspective, we give an overview of immunotherapies leveraging engineering approaches, including the design of biomaterials, delivery strategies and nanotechnology solutions, for the realization of individualized cancer treatments such as nanoparticle vaccines customized with neoantigens, cell therapies based on patient-derived dendritic cells and T cells, and combinations of theranostic strategies. Developments in precision cancer immunotherapy will increasingly rely on the adoption of engineering principles.

Introduction ATRX is a chromatin remodeling protein whose main function is the deposition of the histone variant H3.3. ATRX mutations are widely distributed in glioma, and correlate with alternative lengthening of telomeres (ALT) development, but they also affect other cellular functions related to epigenetic regulation. Areas covered We discuss the main molecular characteristics of ATRX, from its various functions in normal development to the effects of its loss in ATRX syndrome patients and animal models. We focus on the salient consequences of ATRX mutations in cancer, from a clinical to a molecular point of view, focusing on both adult and pediatric glioma. Finally, we will discuss the therapeutic opportunities future research perspectives. Expert opinion ATRX is a major component of various essential cellular pathways, exceeding its functions as a histone chaperone (e.g., DNA replication and repair, chromatin higher-order structure regulation, gene transcriptional regulation, etc.). However, it is unclear how the loss of these functions in ATRX-null cancer cells affects cancer development and progression. We anticipate new treatments and clinical approaches will emerge for glioma and other cancer types as mechanistic and molecular studies on ATRX are only just beginning to reveal the many critical functions of this protein in cancer.

We used hepatitis B virus (HBV) transgenic mice as recipients of cytotoxic T cells (CTLs) specific for the immunodominant Env28–39 epitope (Env28) of HbsAg, and C57BL/6J mice acutely infected with a recombinant replication-deficient adenovirus expressing lacZ (RAd35) to show that platelets accumulate in necroinflammatory foci of the liver during the course of a disease similar to acute hepatitis in humans. Liver disease was monitored by quantifying the activity of serum alanine aminotransferase (sALT), a hepatocellular enzyme that is released into the circulation by necrotic hepatocytes, and by evaluating histological changes at the time of autopsy. Livers from mice sacrificed 2 days after CTL transfer were stained with a mixture of rat monoclonal antibodies (α-PLT) against mouse glycoprotein (GP) Ibα, a receptor exclusively expressed on platelets and megakaryocytes. Livers from mice injected with saline (0.9% NaCl) alone served as controls. Platelets were detectable only inside vessels and hepatic sinusoids in saline-injected controls, while they accumulated alongside apoptotic hepatocytes and inflammatory cells within necroinflammatory foci of the liver in CTL-injected or RAd35-infected animals. The injection of α-PLT caused a >97.5% decrease in the number of circulating platelets (less than 2x104 platelets/μl of blood) within 30 min, and similar low counts were maintained for up to 6 days. Mice that received either saline or an irrelevant antibody (α-Irr) exhibited stable platelet counts (8–10 x 105 platelets/μl of blood). Previous platelet depletion in CTL-injected or RAd35-infected animals reduced the intrahepatic accumulation of virus-specific CTLs and the resulting liver damage, as evidenced by an 80% reduction in sALT activity (from 1600 to 300 U/L) and a reduction the size of necroinflammatory foci (from 6724 μm2 to 1245 μm2) as compared to mice that received α-Irr. Infusion of washed mouse platelets expressing human GP Ibα (thus, insensitive to the depleting effect of α-Plt) within hours after CTL transfer or RAd35 infection restored CTL accumulation and liver disease severity, but not when the infused platelets were pretreated with the activation inhibitor, prostaglandin E1. Accordingly, platelet activation was required to promote CTL/platelet interactions under flow conditions in vitro. Fibrin deposition was abundant within hepatic necroinflammatory foci of CTL-injected or RAd35-infected animals, and markedly decreased in animals that were previously made thrombocytopenic. The platelet-dependent intrahepatic deposition of fibrin could be selectively prevented by anticoagulant treatment of the mice, which had no effect on the platelet count, but this did not ameliorate liver injury. Our findings indicate that activated platelets contribute to CTL-induced liver immunopathology by facilitating the accumulation of CTLs at the site of inflammation, independently of procoagulant function.

Poor efficiency of gene transfer into cancer cells constitutes the major bottleneck of current cancer gene therapy. We reasoned that because tumors are masses of rapidly dividing cells, they would be most efficiently transduced with vector systems allowing transgene propagation. We thus designed two replicative retrovirus -derived vector systems: one inherently replicative vector, and one defective vector propagated by a helper retrovirus. In vitro, both systems achieved very efficient transgene propagation. In immunocompetent mice, replicative vectors transduced >85% tumor cells, whereas defective vectors transduced < 1% under similar conditions. It is noteworthy that viral propagation could be efficiently blocked by azido -thymidine, in vitro and in vivo. In a model of established brain tumors treated with suicide genes, replicative retroviral vectors ( RRVs ) were approximately 1000 times more efficient than defective adenoviral vectors. These results demonstrate the advantage and potential of RRVs and strongly support their development for cancer gene therapy.