Adoptively transferred tumor-specific T cells stimulated ex vivo using herpes simplex virus amplicons encoding 4-1BBL persist in the host and show antitumor activity in vivo

Necroptosis Stimulates Interferon-Mediated Protective Anti-Tumor Immunity

Necroptosis is an inflammatory form of cell suicide that critically depends on the kinase activity of Receptor Interacting Protein Kinase 3 (RIPK3). Previous studies showed that immunization with necroptotic cells conferred protection against subsequent tumor challenge. Since RIPK3 can also promote apoptosis and NF-κB-dependent inflammation, it remains difficult to determine the contribution of necroptosis-associated release of damage-associated molecular patterns (DAMPs) in anti-tumor immunity. Here, we describe a system that allows us to selectively induce RIPK3-dependent necroptosis or apoptosis with minimal NF-κB-dependent inflammatory cytokine expression. In a syngeneic tumor challenge model, immunization with necroptotic cells conferred superior protection against subsequent tumor challenge. Surprisingly, this protective effect required CD4+ T cells rather than CD8+ T cells and is dependent on host type I interferon signaling. Our results provide evidence that death-dependent type I interferon production following necroptosis is sufficient to elicit protective anti-tumor immunity.

Progress towards non-small-cell lung cancer models that represent clinical evolutionary trajectories

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide. Although advances are being made towards earlier detection and the development of impactful targeted therapies and immunotherapies, the 5-year survival of patients with advanced disease is still below 20%. Effective cancer research relies on pre-clinical model systems that accurately reflect the evolutionary course of disease progression and mimic patient responses to therapy. Here, we review pre-clinical models, including genetically engineered mouse models and patient-derived materials, such as cell lines, primary cell cultures, explant cultures and xenografts, that are currently being used to interrogate NSCLC evolution from pre-invasive disease through locally invasive cancer to the metastatic colonization of distant organ sites.

Early detection of doxorubicin-induced cardiotoxicity in rats by its cardiac metabolic signature assessed with hyperpolarized MRI

Doxorubicin (DOX) is a widely used chemotherapeutic agent that can cause serious cardiotoxic side effects culminating in congestive heart failure (HF). There are currently no clinical imaging techniques or biomarkers available to detect DOX-cardiotoxicity before functional decline. Mitochondrial dysfunction is thought to be a key factor driving functional decline, though real-time metabolic fluxes have never been assessed in DOX-cardiotoxicity. Hyperpolarized magnetic resonance imaging (MRI) can assess real-time metabolic fluxes in vivo. Here we show that cardiac functional decline in a clinically relevant rat-model of DOX-HF is preceded by a change in oxidative mitochondrial carbohydrate metabolism, measured by hyperpolarized MRI. The decreased metabolic fluxes were predominantly due to mitochondrial loss and additional mitochondrial dysfunction, and not, as widely assumed hitherto, to oxidative stress. Since hyperpolarized MRI has been successfully translated into clinical trials this opens up the potential to test cancer patients receiving DOX for early signs of cardiotoxicity.

Anti-GD2/4-1BB chimeric antigen receptor T cell therapy for the treatment of Chinese melanoma patients

Background

Chimeric antigen receptor (CAR)-engineered T cells have demonstrated promising clinical efficacy in patients with B cell lymphoma. However, the application of CAR-T cell therapy in the treatment of other solid tumors has been limited. We incorporated 4-1BB into the anti-GD2 CAR-T cells to test their cytotoxicity in melanoma in vitro and in vivo. Moreover, we reported the expression of ganglioside GD2 in non-Caucasian melanoma populations for the first time, thus providing a basis for future clinical research.

Methods

This study included tumor samples from 288 melanoma patients at the Peking University Cancer Hospital & Institute. Clinical data were collected. Immunohistochemical assays using antibodies against ganglioside GD2 were performed on formalin-fixed, paraffin-embedded specimens. The ability of ganglioside GD2 CAR-T cells to kill ganglioside GD2⁺ melanoma cells was evaluated in vitro and in a patient-derived xenograft (PDX) model.

Results

Among the 288 samples, 49.3% of cases (142/288) demonstrated positive staining with ganglioside GD2. The median survival time in patients exhibiting ganglioside GD2 expression was significantly shorter than that in patients without ganglioside GD2 expression (31 vs. 47.1 months, P < 0.001). In the present study, CAR was constructed using a GD2-specific scFv (14.G2a), T cell receptor CD3ζ chain, and the CD137 (4-1BB) costimulatory motif. In addition, the GD2.BBζ CAR-T cells demonstrated specific lysis of ganglioside GD2-expressing melanoma cells in vitro. In two PDX models, mice that received intravenous or local intratumor injections of GD2.BBζ CAR-T cells experienced rapid tumor regression.

Conclusions

These data demonstrate that the rate of GD2 expression in Chinese patients is 49.3%. GD2.BBζ CAR-T cells can both efficiently lyse melanoma in a GD2-specific manner and release Th1 cytokines in an antigen-dependent manner in vitro and in vivo. Anti-GD2/4-1BB CAR-T cells represent a clinically appealing treatment strategy for Chinese melanoma patients exhibiting GD2 expression and provide a basis for future studies of the clinical application of immunotherapy for melanoma.

Electronic supplementary material

The online version of this article (10.1186/s13045-017-0548-2) contains supplementary material, which is available to authorized users.

Enhanced antitumor effects of a dendritic cell vaccine transfected with gastric cancer cell total RNA carrying the 4-1BBL gene in vitro

T cell-mediated antitumor immunity is a cellular immune response that requires two signals. The dendritic cell (DC) has been considered as the most efficient antigen-presenting cell (APC). It plays essential roles in the induction, regulation and maintenance of antitumor immunity in humans. The 4-1BB/4-1BB ligand (4-1BBL) pathway plays crucial roles in immune response, tumor immunity and autoimmune diseases through transduction of T cell co-stimulatory signals. The aim of this study was to generate the preparation protocol for a DC vaccine transfected with gastric cancer cell total ribonucleic acid (RNA) carrying the 4-1 BBL gene in vitro and to investigate its antitumor effects in murine forestomach carcinoma (MFC). The vaccine was prepared by transfecting MFC total RNAs carrying the 4-1BBL gene into the DCs that were isolated from 615 mouse bones. The T cell proliferation rate in the MFC/4-1BBL/DC group was higher than that in the DC group. The tumor cell kill rate in the MFC/4-1BBL/DC group was higher than that in the DC group. ELISA analysis showed that IL-12 and IFN-γ in the MFC/4-1BBL/DC group were more highly expressed compared to the other group. Collectively, our data demonstrate that the DC vaccine transfected with gastric cancer cell total RNA carrying the 4-1BBL gene has a stronger ability to kill gastric cancer cells through promoting T cell proliferation and enhancing the ability of cytotoxic T lymphocytes (CTLs) to kill gastric carcinoma cells and to secrete IL-12 and IFN-γ. Our results provide an effective therapeutic strategy for treating gastric cancer using a DC vaccine.

Engineered artificial antigen presenting cells facilitate direct and efficient expansion of tumor infiltrating lymphocytes

Background

Development of a standardized platform for the rapid expansion of tumor-infiltrating lymphocytes (TILs) with anti-tumor function from patients with limited TIL numbers or tumor tissues challenges their clinical application.

Methods

To facilitate adoptive immunotherapy, we applied genetically-engineered K562 cell-based artificial antigen presenting cells (aAPCs) for the direct and rapid expansion of TILs isolated from primary cancer specimens.

Results

TILs outgrown in IL-2 undergo rapid, CD28-independent expansion in response to aAPC stimulation that requires provision of exogenous IL-2 cytokine support. aAPCs induce numerical expansion of TILs that is statistically similar to an established rapid expansion method at a 100-fold lower feeder cell to TIL ratio, and greater than those achievable using anti-CD3/CD28 activation beads or extended IL-2 culture. aAPC-expanded TILs undergo numerical expansion of tumor antigen-specific cells, remain amenable to secondary aAPC-based expansion, and have low CD4/CD8 ratios and FOXP3+ CD4+ cell frequencies. TILs can also be expanded directly from fresh enzyme-digested tumor specimens when pulsed with aAPCs. These "young" TILs are tumor-reactive, positively skewed in CD8+ lymphocyte composition, CD28 and CD27 expression, and contain fewer FOXP3+ T cells compared to parallel IL-2 cultures.

Conclusion

Genetically-enhanced aAPCs represent a standardized, "off-the-shelf" platform for the direct ex vivo expansion of TILs of suitable number, phenotype and function for use in adoptive immunotherapy.

In vivo persistence, tumor localization, and antitumor activity of CAR-engineered T cells is enhanced by costimulatory signaling through CD137 (4-1BB)

Human T cells engineered to express a chimeric antigen receptor (CAR) specific for folate receptor-α (FRα) have shown robust antitumor activity against epithelial cancers in vitro but not in the clinic because of their inability to persist and home to tumor in vivo. In this study, CARs were constructed containing a FRα-specific scFv (MOv19) coupled to the T-cell receptor CD3ζ chain signaling module alone (MOv19-ζ) or in combination with the CD137 (4-1BB) costimulatory motif in tandem (MOv19-BBζ). Primary human T cells transduced to express conventional MOv19-ζ or costimulated MOv19-BBζ CARs secreted various proinflammatory cytokines, and exerted cytotoxic function when cocultured with FRα(+) tumor cells in vitro. However, only transfer of human T cells expressing the costimulated MOv19-BBζ CAR mediated tumor regression in immunodeficient mice bearing large, established FRα(+) human cancer. MOv19-BBζ CAR T-cell infusion mediated tumor regression in models of metastatic intraperitoneal, subcutaneous, and lung-involved human ovarian cancer. Importantly, tumor response was associated with the selective survival and tumor localization of human T cells in vivo and was only observed in mice receiving costimulated MOv19-BBζ CAR T cells. T-cell persistence and antitumor activity were primarily antigen-driven; however, antigen-independent CD137 signaling by CAR improved T-cell persistence but not antitumor activity in vivo. Our results show that anti-FRα CAR outfitted with CD137 costimulatory signaling in tandem overcome issues of T-cell persistence and tumor localization that limit the conventional FRα T-cell targeting strategy to provide potent antitumor activity in vivo.

Extracellular domain of human 4-1BBL enhanced the function of cytotoxic T-lymphocyte induced by dendritic cell

Interaction of costimulatory molecules and their receptors is crucial for tumor lysate-pulsed dendritic cells (sensitized DC, sDC) to promote T cell activation, clonal expansion and its antitumor immunity. To augment the costimulatory signal may regulate the interaction between DC and cytotoxic T lymphocyte (CTL) and consequently enhance the antitumor response. The costimulatory ligand and receptor pair of 4-1BB/4-1BBL is one of the main factors in the costimulation of CTL. We explored the adjuvant role of a recombinant human 4-1BBL extracellular domain (ex4-1BBL) in modulating CTL activation induced by HepG2 antigen-loaded DC (sDC). The augment effects of sDC in combination with ex4-1BBL on the proliferation, activation, cell survival and cytotoxicity against HepG2 cells of CTL were examined. In the presence of ex4-1BBL, sDC exhibited markedly augmented effects on the above four functions of CTL. These results demonstrate that ex4-1BBL plays an important role in the costimulation pathway for DC-mediated CTL's activation, which might be a useful adjuvant factor for DC-based cancer biotherapy.

Integrating costimulatory agonists to optimize immune-based cancer therapies

While immunotherapy for cancer has become increasingly popular, clinical benefits for such approaches remain limited. This is likely due to tumor-associated immune suppression, particularly in the advanced-disease setting. Thus, a major goal of novel immunotherapeutic design has become the coordinate reversal of existing immune dysfunction and promotion of specific tumoricidal T-cell function. Costimulatory members of the TNF-receptor family are important regulators of T-cell-mediated immunity. Notably, agonist ligation of these receptors restores potent antitumor immunity in the tumor-bearing host. Current Phase I/II evaluation of TNF-receptor agonists as single-modality therapies will illuminate their safety, mechanism(s) of action, and best use in prospective combinational immunotherapy approaches capable of yielding superior benefits to cancer patients.

Soluble B and T lymphocyte attenuator possesses antitumor effects and facilitates heat shock protein 70 vaccine-triggered antitumor immunity against a murine TC-1 cervical cancer model in vivo

B and T lymphocyte attenuator (BTLA)-herpesvirus entry mediator (HVEM) signaling coinhibitory pathway is believed to impair antitumor immune competences. An intriguing unresolved question is whether blockade of BTLA-HVEM guides an effective therapeutic tool against established tumors. To address this issue, we constructed a eukaryotic expression plasmid (psBTLA) that expressed the extracellular domain of murine BTLA (soluble form of BTLA), which could bind HVEM, the ligand of BTLA, and block BTLA-HVEM interactions. The data in this study showed that treatment by injection of psBTLA resulted in down-regulation of IL-10 and TGF-beta and promotion of dendritic cell function by increasing the expression of B7-1 and IL-12, but the adaptive antitumor immune responses achieved by psBTLA administration alone were limited and could not eradicate the tumor effectively. Next, we evaluated the immunotherapeutic efficacy and mechanism of combination therapy of heat shock protein 70 (HSP70) vaccine/psBTLA by using murine TC-1 cervical cancer mice as an ectopic tumor model. Our in vivo studies revealed that treatment with HSP70 vaccine alone did not lead to satisfactory tumor growth inhibition, whereas cotreatment with psBTLA significantly improved antitumor immunity and compensated the deficiency of HSP70 vaccine by increasing the expression of Th1 cytokines, IL-2, and IFN-gamma and decreasing transcription levels of IL-10, TGF-beta, and Foxp3 in the tumor microenvironment. Taken together, our findings indicate that blocking the BTLA-HVEM interaction with sBTLA enhances antitumor efficacy and results in a significant synergistic effect against existent tumor cells in vivo when combined with the HSP70 vaccine.

Immunobiology of cancer therapies targeting CD137 and B7-H1/PD-1 cosignal pathways

Cancer immunotherapy is finally entering a new era with manipulation of cosignaling pathways as a therapeutic approach, for which the principle was proved nearly two decades ago. In addition to CTLA-4, CD137 and B7-H1/PD-1 pathways are two new targets in the stage. CD137 pathway is costimulatory and its agonistic antibody delivers potent signal to drive T cell growth and activation. On the other hand, blockade of B7-H1/PD-1 pathway with antagonistic antibody has shown to protect ongoing T cell responses from impairment by immune evasion mechanism in cancer microenvironment. With these tools in hand, a mechanism-based design of combined immunotherapy with high efficacy is becoming a reality.

Inhibition of succinate dehydrogenase dysregulates histone modification in mammalian cells

Remodelling of mitochondrial metabolism is a hallmark of cancer. Mutations in the genes encoding succinate dehydrogenase (SDH), a key Krebs cycle component, are associated with hereditary predisposition to pheochromocytoma and paraganglioma, through mechanisms which are largely unknown. Recently, the jumonji-domain histone demethylases have emerged as a novel family of 2-oxoglutarate-dependent chromatin modifiers with credible functions in tumourigenesis. Using pharmacological and siRNA methodologies we show that increased methylation of histone H3 is a general consequence of SDH loss-of-function in cultured mammalian cells and can be reversed by overexpression of the JMJD3 histone demethylase. ChIP analysis revealed that the core promoter of IGFBP7, which encodes a secreted protein upregulated after loss of SDHB, showed decreased occupancy by H3K27me3 in the absence of SDH. Finally, we provide the first evidence that the chief (type I) cell is the major methylated histone-immunoreactive constituent of paraganglioma. These results support the notion that loss of mitochondrial function alters epigenetic processes and might provide a signature methylation mark for paraganglioma.

Host lymphodepletion enhances the therapeutic activity of an oncolytic vaccinia virus expressing 4-1BB ligand

Oncolytic viral vectors have shown promise as antitumor therapeutic agents but their effectiveness is complicated by induction of antiviral antibody responses and rapid host clearance of recombinant vectors. We developed a recombinant oncolytic vaccinia virus expressing the 4-1BBL T-cell costimulatory molecule (rV-4-1BBL) and showed modest tumor regression in the poorly immunogenic B16 murine melanoma model. To improve the therapeutic potential of this vector, we tested the antitumor activity of local intratumoral injection in the setting of host lymphodepletion, which has been shown to augment vaccination and adoptive T-cell therapy. In this model, rV-4-1BBL injection in the setting of lymphodepletion promoted MHC class I expression, reduced antiviral antibody titers, promoted viral persistence, and rescued effector-memory CD8(+) T cells, significantly improving the therapeutic effectiveness of the oncolytic vector. These data suggest that vaccination with rV-4-1BBL in the setting of host nonmyeloablative lymphodepletion represents a logical strategy for improving oncolytic vaccination in melanoma, and perhaps other cancers as well.