Probes for INS

T cells expressing chimeric antigen receptors (CART) have shown significant promise in clinical trials to treat hematologic malignancies, but their efficacy in solid tumors has been limited. Oncolytic viruses have the potential to act in synergy with immunotherapies due to their immunogenic oncolytic properties and the opportunity of incorporating therapeutic transgenes in their genomes. Here, we hypothesized that an oncolytic adenovirus armed with an EGFR-targeting, bispecific T-cell engager (OAd-BiTE) would improve the outcome of CART-cell therapy in solid tumors. We report that CART cells targeting the folate receptor alpha (FR-α) successfully infiltrated preestablished xenograft tumors but failed to induce complete responses, presumably due to the presence of antigen-negative cancer cells. We demonstrated that OAd-BiTE-mediated oncolysis significantly improved CART-cell activation and proliferation, while increasing cytokine production and cytotoxicity, and showed an in vitro favorable safety profile compared with EGFR-targeting CARTs. BiTEs secreted from infected cells redirected CART cells toward EGFR in the absence of FR-α, thereby addressing tumor heterogeneity. BiTE secretion also redirected CAR-negative, nonspecific T cells found in CART-cell preparations toward tumor cells. The combinatorial approach improved antitumor efficacy and prolonged survival in mouse models of cancer when compared with the monotherapies, and this was the result of an increased BiTE-mediated T-cell activation in tumors. Overall, these results demonstrated that the combination of a BiTE-expressing oncolytic virus with adoptive CART-cell therapy overcomes key limitations of CART cells and BiTEs as monotherapies in solid tumors and encourage its further evaluation in human trials.

Gastric cancer is the fifth most common cancer and third leading cause of cancer-related death worldwide. Several studies on angiogenic blocking agents in gastric cancer revealing promising results by the use of monoclonal antibodies against VEGFA or its receptor VEGFR2 or against VEGFA activating pathway. The validation of biomarkers useful to better organize the clinical trials involving anti-angiogenic therapies is crucial. Molecular markers such as RNA are increasingly used for cancer diagnosis, prognosis, and therapy guidance as in the case of the targeted therapies concerning the inhibition of angiogenesis. The aim of this study is to set the conditions for evaluating the expression of VEGFA and VEGFR2 in gastric cancer specimens and in healthy gastric mucosa by the use of RNAscope, a novel RNA in situ hybridization (ISH) method that allows the visualization of a specific gene expression in individual cells. We found the increased expression of VEGFA in the tubular glands and VEGFR2 in the endothelium of gastric cancer samples mainly in the T2, T3 and T4 stages of tumor progression as compared to the healthy controls. These results obtained by the application of this highly sensitive method for oligonucleotide detection the role of angiogenesis in gastric cancer progression already highlighted by conventional immunohistochemical methods, and offer significant promise as a new platform for developing and implementing RNA-based molecular diagnostics also in the conditions in which immunohistochemistry is not applicable.

Amplification of vascular endothelial growth factor A (VEGFA) has been recently reported in TFEB-amplified renal cell carcinomas regardless the level of TFEB amplification. We sought to determine VEGFA amplification by fluorescent in situ hybridization (FISH) and VEGFA mRNA expression by in situ hybridization (RNAscope 2.5) in a series of 10 renal cell carcinomas with TFEB gene alterations, either amplification and/or rearrangement (t(6;11) renal cell carcinoma). TFEB gene rearrangement was demonstrated in eight cases, whereas the remaining two cases showed a high level of TFEB (> 10 copies of fluorescent signals) gene amplification without evidence of rearrangement. Among the eight t(6;11) renal cell carcinomas (TFEB-rearranged cases), one case displayed a high level of TFEB gene amplification and two showed increased TFEB gene copy number (3-4 copies of fluorescent signals). Those three cases behaved aggressively. By FISH, VEGFA was amplified in all three cases with TFEB amplification and increased VEGFA gene copy number was observed in the two aggressive cases t(6;11) renal cell carcinomas with an overlapping increased number of TFEB fluorescent signals. Overall, VEGFA mRNA expression was observed in 8 of 10 cases (80%); of these 8 cases, 3 cases showed high-level TFEB amplification, one case showed TFEB rearrangement with increased TFEB gene copy number, whereas four showed TFEB gene rearrangement without increased copy number. In summary, VEGFA amplification/increased gene copy number and VEGFA mRNA expression occur in TFEB-amplified renal cell carcinoma, but also in a subset of t(6;11) renal cell carcinoma demonstrating aggressive behavior, and in unamplified conventional t(6;11) renal cell carcinoma suggesting VEGFA as potential therapeutic target in these neoplasms even in the absence of TFEB amplification. We finally propose that all the renal tumors showing morphological characteristics suggesting t(6;11) renal cell carcinoma and all unclassified renal cell carcinomas, either high grade or low grade, should immunohistochemically be evaluated for cathepsin K and/or Melan-A and if one of them is positive, tested for TFEB gene alteration and VEGFA gene amplification.

Angiostasis mediated by IFNγ is a key mechanism of anti-tumor immunity; however, the effect of IFNγ on host VEGFA-expressing cells during tumor progression is still elusive. Here, we developed transgenic mice with IFNγ receptor (IFNγR) expression under control of the Vegfa promoter (V-γR). In these mice, the IFNγ responsiveness of VEGFA -expressing cells led to a dramatic growth suppression of transplanted lung carcinoma cells. Surprisingly, increased mortality and tumor metastasis were observed in the tumor-bearing V-γR mice, in comparison to the control wild type and IFNγR-deficient mice. Further study showed that perivascular cells were VEGFA-expressing cells and potential IFNγ targets. In vivo, tumor vascular perfusion and pericyte association with blood vessels were massively disrupted in V-γR mice. In vitro, IFNγ inhibited TGF-β-signaling through upregulating SMAD7 and therefore, down-regulated N-cadherin expression in pericytes. Importantly, IFNγ neutralization in vivo using a monoclonal antibody reduced tumor metastasis. Together, the results suggest that IFNγR-mediated dissociation of perivascular cells from blood vessels contributes to the acceleration of tumor metastasis. Thus the inhibition of tumor growth via IFNγ-induced angiostasis might also accelerate tumor metastasis.

Immune recognition of tumor-expressed antigens by cytotoxic CD8+ T cells is the foundation of adoptive T cell therapy (ACT) and has been shown to elicit significant tumor regression. However, therapy-induced selective pressure can sculpt the antigenicity of tumors, resulting in outgrowth of variants that lose the target antigen. We demonstrate that tumor relapse from ACT and subsequent oncolytic viral vaccination can be prevented using class I HDACi, MS-275. Drug delivery subverted the phenotype of tumor-infiltrating CD11b+ Ly6Chi Ly6G- myeloid cells, favoring NOS2/ROS secretion and pro-inflammatory genes characteristic of M1 polarization. Simultaneously, MS-275 abrogated the immunosuppressive function of tumor-infiltrating myeloid cells and reprogrammed them to eliminate antigen-negative tumor cells in a caspase-dependent manner. Elevated IFN-γ within the tumor microenvironment suggests that MS-275 modulates the local cytokine landscape to favor antitumor myeloid polarization through the IFN-γR/STAT1 signaling axis. Exploiting tumor-infiltrating myeloid cell plasticity thus complements T cell therapy in targeting tumor heterogeneity and immune escape.

Medulloblastomas comprise a heterogeneous group of tumours and can be subdivided into four molecular subgroups (WNT, SHH, Group 3 and Group 4) with distinct prognosis, biological behaviour and implications for targeted therapies. Few experimental models exist of the aggressive and poorly characterized Group 3 tumours. In order to establish a reproducible transplantable Group 3 medulloblastoma model for preclinical therapeutic studies, we acquired a patient-derived tumour sphere culture and inoculated low-passage spheres into the cerebellums of NOD-scid mice. Mice developed symptoms of brain tumours with a latency of 17-18 weeks. Neurosphere cultures were re-established and serially transplanted for 3 generations, with a negative correlation between tumour latency and numbers of injected cells. Xenografts replicated the phenotype of the primary tumour, including high degree of clustering in DNA methylation analysis, high proliferation, expression of tumour markers, MYC amplification and elevated MYC expression, and sensitivity to the MYC inhibitor JQ1. Xenografts maintained maintained expression of tumour-derived VEGFA and stromal-derived COX-2. VEGFA, COX-2 and c-Myc are highly expressed in Group 3 compared to other medulloblastoma subgroups, suggesting that these molecules are relevant therapeutic targets in Group 3medulloblastoma.