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Mounting evidence suggests that the tumor microenvironment is profoundly immunosuppressive. Thus, mitigating tumor immunosuppression is crucial for inducing sustained antitumor immunity. Whereas previous studies involved intratumoral injection, we report here an inhalable nanoparticle-immunotherapy system targeting pulmonary antigen presenting cells (APCs) to enhance anticancer immunity against lung metastases. Inhalation of phosphatidylserine coated liposome loaded with STING agonist cyclic guanosine monophosphate–adenosine monophosphate (NP-cGAMP) in mouse models of lung metastases enables rapid distribution of NP-cGAMP to both lungs and subsequent uptake by APCs without causing immunopathology. NP-cGAMP designed for enhanced cytosolic release of cGAMP stimulates STING signaling and type I interferons production in APCs, resulting in the pro-inflammatory tumor microenvironment in multifocal lung metastases. Furthermore, fractionated radiation delivered to one tumor-bearing lung synergizes with inhaled NP-cGAMP, eliciting systemic anticancer immunity, controlling metastases in both lungs, and conferring long-term survival in mice with lung metastases and with repeated tumor challenge. Successful anticancer immunotherapy should induce robust systemic immunity against metastases. Here, the authors engineer an inhalable nano-STING agonist, which synergizes with fractionated radiation to control lung metastases and confers long-term systemic antitumor immunity in mice.

Aberrant EGFR signaling is common in glioblastoma. The authors show that inhibiting EGFR leads to increased secretion of TNF and activation of a survival pathway in cancer cells. A combined inhibition of EGFR and TNF signaling inhibits tumor growth in a mouse model, suggesting a new treatment for patients with glioblastoma. Aberrant epidermal growth factor receptor (EGFR) signaling is widespread in cancer, making the EGFR an important target for therapy. EGFR gene amplification and mutation are common in glioblastoma (GBM), but EGFR inhibition has not been effective in treating this tumor. Here we propose that primary resistance to EGFR inhibition in glioma cells results from a rapid compensatory response to EGFR inhibition that mediates cell survival. We show that in glioma cells expressing either EGFR wild type or the mutant EGFRvIII, EGFR inhibition triggers a rapid adaptive response driven by increased tumor necrosis factor (TNF) secretion, which leads to activation in turn of c-Jun N-terminal kinase (JNK), the Axl receptor tyrosine kinase and extracellular signal–regulated kinases (ERK). Inhibition of this adaptive axis at multiple nodes rendered glioma cells with primary resistance sensitive to EGFR inhibition. Our findings provide a possible explanation for the failures of anti-EGFR therapy in GBM and suggest a new approach to the treatment of EGFR-expressing GBM using a combination of EGFR and TNF inhibition.

The interleukin-13 receptor alpha2 (IL-13Rα2) is a cancer-associated receptor overexpressed in human glioblastoma multiforme (GBM). This receptor is undetectable in normal brain which makes it a highly suitable target for diagnostic and therapeutic purposes. However, the pathological role of this receptor in GBM remains to be established. Here we report that IL-13Rα2 alone induces invasiveness of human GBM cells without affecting their proliferation. In contrast, in the presence of the mutant EGFR (EGFRvIII), IL-13Rα2 promotes GBM cell proliferation in vitro and in vivo. Mechanistically, the cytoplasmic domain of IL-13Rα2 specifically binds to EGFRvIII, and this binding upregulates the tyrosine kinase activity of EGFRvIII and activates the RAS/RAF/MEK/ERK and STAT3 pathways. Our findings support the “To Go or To Grow” hypothesis whereby IL-13Rα2 serves as a molecular switch from invasion to proliferation, and suggest that targeting both receptors with STAT3 signaling inhibitor might be a therapeutic approach for the treatment of GBM. Interleukin-13 receptor alpha 2 is highly expressed in glioblastoma multiforme but its role in this malignancy is unclear. Here the authors show that this receptor interacts with mutant EGFR, stimulating its kinase activity, thus inducing proliferation.

Inhibition of RTK pathways in cancer triggers an adaptive response that promotes therapeutic resistance. Because the adaptive response is multifaceted, the optimal approach to blunting it remains undetermined. TNF upregulation is a biologically significant response to EGFR inhibition in NSCLC. Here, we compared a specific TNF inhibitor (etanercept) to thalidomide and prednisone, two drugs that block TNF and also other inflammatory pathways. Prednisone is significantly more effective in suppressing EGFR inhibition-induced inflammatory signals. Remarkably, prednisone induces a shutdown of bypass RTK signaling and inhibits key resistance signals such as STAT3, YAP and TNF-NF-κB. Combined with EGFR inhibition, prednisone is significantly superior to etanercept or thalidomide in durably suppressing tumor growth in multiple mouse models, indicating that a broad suppression of adaptive signals is more effective than blocking a single component. We identify prednisone as a drug that can effectively inhibit adaptive resistance with acceptable toxicity in NSCLC and other cancers. TNF signalling was reported to mediate resistance to EGFR inhibition in non-small cell lung cancer (NSCLC). Here, the authors examine the efficacy of a broad versus focused targeting of this resistance, and they show that a broad inhibitor of inflammation, prednisone is the most effective.

Mechanisms that alter protein phosphatase 2A (PP2A)‐dependent lung tumour suppression via the I2PP2A/SET oncoprotein are unknown. We show here that the tumour suppressor ceramide binds I2PP2A/SET selectively in the nucleus and including its K209 and Y122 residues as determined by molecular modelling/simulations and site‐directed mutagenesis. Because I2PP2A/SET was found overexpressed, whereas ceramide was downregulated in lung tumours, a sphingolipid analogue drug, FTY720, was identified to mimick ceramide for binding and targeting I2PP2A/SET, leading to PP2A reactivation, lung cancer cell death, and tumour suppression in vivo . Accordingly, while molecular targeting of I2PP2A/SET by stable knockdown prevented further tumour suppression by FTY720, reconstitution of WT‐I2PP2A/SET expression restored this process. Mechanistically, targeting I2PP2A/SET by FTY720 mediated PP2A/RIPK1‐dependent programmed necrosis (necroptosis), but not by apoptosis. The RIPK1 inhibitor necrostatin and knockdown or genetic loss of RIPK1 prevented growth inhibition by FTY720. Expression of WT‐ or death‐domain‐deleted (DDD)‐RIPK1, but not the kinase‐domain‐deleted (KDD)‐RIPK1, restored FTY720‐mediated necroptosis in RIPK1 −/− MEFs. Thus, these data suggest that targeting I2PP2A/SET by FTY720 suppresses lung tumour growth, at least in part, via PP2A activation and necroptosis mediated by the kinase domain of RIPK1. Graphical Abstract The authors show that targeting I2PP2A/SET by FTY720 suppresses lung tumour growth via PP2A‐dependent RIPK1 activation leading to necroptosis.

It is recognized that cancer cells exhibit highly elevated glucose metabolism compared to non-tumor cells. We have applied in vivo optical imaging to study dynamic uptake of a near-infrared dye-labeled glucose analogue, 2-deoxyglucose (2-DG) by orthotopic glioma in a mouse model. The orthotopic glioma model was established by surgically implanting U87-luc glioma cells into the right caudal nuclear area of nude mice. Intracranial tumor growth was monitored longitudinally by bioluminescence imaging and MRI. When tumor size reached >4 mm diameter, dynamic fluorescence imaging was performed after an injection of the NIR labeled 2-DG, IRDye800CW 2-DG. Real-time whole body images acquired immediately after i.v. infusion clearly visualized the near-infrared dye circulating into various internal organs sequentially. Dynamic fluorescence imaging revealed significantly higher signal intensity in the tumor side of the brain than the contralateral normal brain 24 h after injection (tumor/normal ratio, TNR = 2.8+/-0.7). Even stronger contrast was achieved by removing the scalp (TNR = 3.7+/-1.1) and skull (TNR = 4.2+/-1.1) of the mice. In contrast, a control dye, IRDye800CW carboxylate, showed little difference (1.1+/-0.2). Ex vivo fluorescence imaging performed on ultrathin cryosections (20 microm) of tumor bearing whole brain revealed distinct tumor margins. Microscopic imaging identified cytoplasmic locations of the 2-DG dye in tumor cells. Our results suggest that the near-infrared dye labeled 2-DG may serve as a useful fluorescence imaging probe to noninvasively assess intracranial tumor burden in preclinical animal models.

Severe neuronal loss in the hippocampus, that is, hippocampal sclerosis (HS), can be seen in 3 main clinical contexts: dementia (particularly frontoteniporal lobar degeneration (FTLD)), temporal lobe epilepsy (TLE), and hippocampal ischemic injury (H-I). It has been suggested that, shared pathogenetic mechanisms may underlie selective vulnerability of the hippocampal subfields such as the CAl in these conditions. The authors have determined the extent of neuronal loss in cases of HS-FTLD, HS-TLE, and H-I. Immunohistochemistry for zinc transporter 3 was used, to help define the CA3/CA2 border in the routinely processed human autopsy tissue samples. The subiculum was involved in 57% of HS-FTLD, 10% of H-I, and 0% of MS-TLE cases. The CA regions other than CAl were involved in 57% of HS-TLE, 30% of H1, and 0% of HS-FTLD cases. The distal third of CAl was involved in 79% of HS- FTLD, 35% of H-I, and 37% of MS-TLE cases. These findings support heterogeneity in the pathogenesis of HS.

According to the recently updated World Health Organization (WHO) classification (2016), grade II–III astrocytomas are divided into IDH-wildtype and IDH-mutant groups, the latter being significantly less aggressive in terms of both progression-free and total survival. We identified a small cohort of WHO grade II–III astrocytomas that harbored the IDH1 R132H mutation, as confirmed by both immunohistochemistry and molecular sequence analysis, which nonetheless had unexpectedly rapid recurrence and subsequent progression to glioblastoma. Among these four cases, the mean time to recurrence as glioblastoma was only 16 months and the mean total survival among the three patients who have died during the follow-up was only 31 months. We hypothesized that these tumors had other, unfavorable genetic or epigenetic alterations that negated the favorable effect of the IDH mutation. We applied genome-wide profiling with a methylation array (Illumina Infinium Human Methylation 450k) to screen for genetic and epigenetic alterations in these tumors. As expected, the methylation profiles of all four tumors were found to match most closely with IDH-mutant astrocytomas. Compared with a control group of four indolent, age-similar WHO grade II–III astrocytomas, the tumors showed markedly increased levels of overall copy number changes, but no consistent specific genetic alterations were seen across all of the tumors. While most IDH-mutant WHO grade II–III astrocytomas are relatively indolent, a subset may rapidly recur and progress to glioblastoma. The precise underlying cause of the increased aggressiveness in these gliomas remains unknown, although it may be associated with increased genomic instability.

Malignant pleural effusion (MPE) is indicative of terminal malignancy with a uniformly fatal prognosis. Often, two distinct compartments of tumour microenvironment, the effusion and disseminated pleural tumours, co-exist in the pleural cavity, presenting a major challenge for therapeutic interventions and drug delivery. Clinical evidence suggests that MPE comprises abundant tumour-associated myeloid cells with the tumour-promoting phenotype, impairing antitumour immunity. Here we developed a liposomal nanoparticle loaded with cyclic dinucleotide (LNP-CDN) for targeted activation of stimulators of interferon genes signalling in macrophages and dendritic cells and showed that, on intrapleural administration, they induce drastic changes in the transcriptional landscape in MPE, mitigating the immune cold MPE in both effusion and pleural tumours. Moreover, combination immunotherapy with blockade of programmed death ligand 1 potently reduced MPE volume and inhibited tumour growth not only in the pleural cavity but also in the lung parenchyma, conferring significantly prolonged survival of MPE-bearing mice. Furthermore, the LNP-CDN-induced immunological effects were also observed with clinical MPE samples, suggesting the potential of intrapleural LNP-CDN for clinical MPE immunotherapy.Malignant pleural effusion (MPE) is the terminal stage of cancer and the current standard of care for MPE is largely palliative. Here the authors design a liposomal nanoparticle loaded with cyclic dinucleotide for targeted activation of STING signalling in macrophages and dendritic cells and show that, on intrapleural administration, the nanoparticle effectively mitigates the immune cold MPE and significantly augments the checkpoint blockade immunotherapy in a mouse MPE model and clinical patients’ samples.

Despite therapeutic advancements, the prognosis of locally advanced non-small cell lung cancer (LANSCLC), which has invaded multiple lobes or the other lung and intrapulmonary lymph nodes, remains poor. The emergence of immunotherapy with immune checkpoint blockade (ICB) is transforming cancer treatment. However, only a fraction of lung cancer patients benefit from ICB. Significant clinical evidence suggests that the proinflammatory tumor microenvironment (TME) and programmed death-ligand 1 (PD-L1) expression correlate positively with response to the PD-1/PD-L1 blockade. We report here a liposomal nanoparticle loaded with cyclic dinucleotide and aerosolized (AeroNP-CDN) for inhalation delivery to deep-seated lung tumors and target CDN to activate stimulators of interferon (IFN) genes in macrophages and dendritic cells (DCs). Using a mouse model that recapitulates the clinical LANSCLC, we show that AeroNP-CDN efficiently mitigates the immunosuppressive TME by reprogramming tumor-associated macrophage from the M2 to M1 phenotype, activating DCs for effective tumor antigen presentation and increasing tumor-infiltrating CD8 + T cells for adaptive anticancer immunity. Intriguingly, activation of interferons by AeroNP-CDN also led to increased PD-L1 expression in lung tumors, which, however, set a stage for response to anti-PD-L1 treatment. Indeed, anti-PD-L1 antibody-mediated blockade of IFNs-induced immune inhibitory PD-1/PD-L1 signaling further prolonged the survival of the LANSCLC-bearing mice. Importantly, AeroNP-CDN alone or combination immunotherapy was safe without local or systemic immunotoxicity. In conclusion, this study demonstrates a potential nano-immunotherapy strategy for LANSCLC, and mechanistic insights into the evolution of adaptive immune resistance provide a rational combination immunotherapy to overcome it.