Preexisting immunity: barrier or bridge to effective oncolytic virus therapy?

Oncolytic viruses (OVs) represent a highly promising treatment strategy for a wide range of cancers, by mediating both the direct killing of tumor cells as well as mobilization of antitumor immune responses. As many OVs circulate in the human population, preexisting OV-specific immune responses are prevalent. Indeed, neutralizing antibodies (NAbs) are abundantly present in the human population for commonly used OVs, such as Adenovirus type 5 (Ad5), Herpes Simplex Virus-1 (HSV-1), Vaccinia virus, Measles virus, and Reovirus. This review discusses (pre)clinical evidence regarding the effect of preexisting immunity against OVs on two distinct aspects of OV therapy; OV infection and spread, as well as the immune response induced upon OV therapy. Combined, this review provides evidence that consideration of preexisting immunity is crucial in realizing the full potential of the highly promising therapeutic implementation of OVs. Future investigation of current gaps in knowledge highlighted in this review should yield a more complete understanding of this topic, ultimately allowing for better and more personalized OV therapies.</p

Biohybrid Vaccines for Improved Treatment of Aggressive Melanoma with Checkpoint Inhibitor

Recent approaches in the treatment of cancer focus on involving the immune system to control the tumor growth. The administration of immunotherapies, like checkpoint inhibitors, has shown impressive results in the long term survival of patients. Cancer vaccines are being investigated as further tools to prime tumor-specific immunity. Biomaterials show potential as adjuvants in the formulation of vaccines, and biomimetic elements derived from the membrane of tumor cells may widen the range of antigens contained in the vaccine. Here, we show how mice presenting an aggressive melanoma tumor model treated twice with the complete nanovaccine formulation showed control on the tumor progression, while in a less aggressive model, the animals showed remission and control on the tumor progression, with a modification in the immunological profile of the tumor microenvironment. We also prove that co-administration of the nanovaccine together with a checkpoint inhibitor increases the efficacy of the treatment (87.5% of the animals responding, with 2 remissions) compared to the checkpoint inhibitor alone in the B16.0VA model. Our platform thereby shows potential applications as a cancer nanovaccine in combination with the standard clinical care treatment for melanoma cancers

Intertumoral differences dictate the outcome of TGF-β blockade on the efficacy of viro-immunotherapy

The absence of T cells in the tumor microenvironment of solid tumors is a major barrier to cancer immunotherapy efficacy. Oncolytic viruses, including reovirus type 3 Dearing (Reo), can recruit CD8+ T cells to the tumor and thereby enhance the efficacy of immunotherapeutic strategies that depend on high T-cell density, such as CD3-bispecific antibody (bsAb) therapy. TGF-β signaling might represent another barrier to effective Reo&CD3-bsAb therapy due to its immunoinhibitory characteristics. Here, we investigated the effect of TGF-β blockade on the antitumor efficacy of Reo&CD3-bsAb therapy in the preclinical pancreatic KPC3 and colon MC38 tumor models, where TGF-β signaling is active. TGF-β blockade impaired tumor growth in both KPC3 and MC38 tumors. Furthermore, TGF-β blockade did not affect reovirus replication in both models and significantly enhanced the Reo-induced T-cell influx in MC38 colon tumors. Reo administration decreased TGF-β signaling in MC38 tumors but instead increased TGF-β activity in KPC3 tumors, resulting in the accumulation of α-smooth muscle actin (αSMA+) fibroblasts. In KPC3 tumors, TGF-β blockade antagonized the antitumor effect of Reo&CD3-bsAb therapy, even though T-cell influx and activity were not impaired. Moreover, genetic loss of TGF-β signaling in CD8+ T cells had no effect on therapeutic responses. In contrast, TGF-β blockade significantly improved therapeutic efficacy of Reo&CD3-bsAb in mice bearing MC38 colon tumors, resulting in a 100% complete response. Further understanding of the factors that determine this intertumor dichotomy is required before TGF-β inhibition can be exploited as part of viroimmunotherapeutic combination strategies to improve their clinical benefit.Significance:Blockade of the pleiotropic molecule TGF-β can both improve and impair the efficacy of viro-immunotherapy, depending on the tumor model. While TGF-β blockade antagonized Reo&CD3-bsAb combination therapy in the KPC3 model for pancreatic cancer, it resulted in 100% complete responses in the MC38 colon model. Understanding factors underlying this contrast is required to guide therapeutic application.Cancer Signaling networks and Molecular Therapeutic

Fatigue, quality of life and physical fitness following an exercise intervention in multiple myeloma survivors (MASCOT): an exploratory randomised Phase 2 trial utilising a modified Zelen design

Background: Exercise may improve fatigue in multiple myeloma survivors, but trial evidence is limited, and exercise may be perceived as risky in this older patient group with osteolytic bone destruction. Methods: In this Phase 2 Zelen trial, multiple myeloma survivors who had completed treatment at least 6 weeks ago, or were on maintenance only, were enrolled in a cohort study and randomly assigned to usual care or a 6-month exercise programme of tailored aerobic and resistance training. Outcome assessors and usual care participants were masked. The primary outcome was the FACIT-F fatigue score with higher scores denoting less fatigue. Results: During 2014–2016, 131 participants were randomised 3:1 to intervention (n = 89) or usual care (n = 42) to allow for patients declining allocation to the exercise arm. There was no difference between groups in fatigue at 3 months (between-group mean difference: 1.6 [95% CI: −1.1–4.3]) or 6 months (0.3 [95% CI: −2.6–3.1]). Muscle strength improved at 3 months (8.4 kg [95% CI: 0.5–16.3]) and 6 months (10.8 kg [95% CI: 1.2–20.5]). Using per-protocol analysis, cardiovascular fitness improved at 3 months (+1.2 ml/kg/min [95% CI: 0.3–3.7]). In participants with clinical fatigue (n = 17), there was a trend towards less fatigue with exercise over 6 months (6.3 [95% CI: −0.6–13.3]). There were no serious adverse events. Conclusions: Exercise appeared safe and improved muscle strength and cardiovascular fitness, but benefits in fatigue appeared limited to participants with clinical fatigue at baseline. Future studies should focus on patients with clinical fatigue. Clinical trial registration: The study was registered with ISRCTN (38480455) and is completed

Preconditioning of the tumor microenvironment with oncolytic reovirus converts CD3-bispecific antibody treatment into effective immunotherapy

Background T-cell-engaging CD3-bispecific antibodies (CD3-bsAbs) are promising modalities for cancer immunotherapy. Although this therapy has reached clinical practice for hematological malignancies, the absence of sufficient infiltrating T cells is a major barrier for efficacy in solid tumors. In this study, we exploited oncolytic reovirus as a strategy to enhance the efficacy of CD3-bsAbs in immune-silent solid tumors. Methods The mutant p53 and K-ras induced murine pancreatic cancer model KPC3 resembles human pancreatic ductal adenocarcinomas with a desmoplastic tumor microenvironment, low T-cell density and resistance to immunotherapy. Immune-competent KPC3 tumorbearing mice were intratumorally injected with reovirus type 3 Dearing strain and the reovirus-induced changes in the tumor microenvironment and spleen were analyzed over time by NanoString analysis, quantitative RT-PCR and multicolor flow cytometry. The efficacy of reovirus in combination with systemically injected CD3-bsAbs was evaluated in immune-competent mice with established KPC3 or B16.F10 tumors, and in the close-to-patient human epidermal growth factor receptor 2 (HER2)+ breast cancer model BT474 engrafted in immunocompromised mice with human T cells as effector cells. Results Replication-competent reovirus induced an early interferon signature, followed by a strong influx of natural killer cells and CD8+ T cells, at the cost of FoxP3+ Tregs. Viral replication declined after 7 da

NKG2A is a late immune checkpoint on CD8 T cells and marks repeated stimulation and cell division

The surface inhibitory receptor NKG2A forms heterodimers with the invariant CD94 chain and is expressed on a subset of activated CD8 T cells. As antibodies to block NKG2A are currently tested in several efficacy trials for different tumor indications, it is important to characterize the NKG2A(+) CD8 T cell population in the context of other inhibitory receptors. Here we used a well-controlled culture system to study the kinetics of inhibitory receptor expression. Naive mouse CD8 T cells were synchronously and repeatedly activated by artificial antigen presenting cells in the presence of the homeostatic cytokine IL-7. The results revealed NKG2A as a late inhibitory receptor, expressed after repeated cognate antigen stimulations. In contrast, the expression of PD-1, TIGIT and LAG-3 was rapidly induced, hours after first contact and subsequently down regulated during each resting phase. This late, but stable expression kinetics of NKG2A was most similar to that of TIM-3 and CD39. Importantly, single-cell transcriptomics of human tumor-infiltrating lymphocytes (TILs) showed indeed that these receptors were often coexpressed by the same CD8 T cell cluster. Furthermore, NKG2A expression was associated with cell division and was promoted by TGF-beta in vitro, although TGF-beta signaling was not necessary in a mouse tumor model in vivo. In summary, our data show that PD-1 reflects recent TCR triggering, but that NKG2A is induced after repeated antigen stimulations and represents a late inhibitory receptor. Together with TIM-3 and CD39, NKG2A might thus mark actively dividing tumor-specific TILs.Experimental cancer immunology and therap

Dendritic cell vaccination and CD40-agonist combination therapy licenses T cell-dependent antitumor immunity in a pancreatic carcinoma murine model

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is notoriously resistant to treatment including checkpoint-blockade immunotherapy. We hypothesized that a bimodal treatment approach consisting of dendritic cell (DC) vaccination to prime tumor-specific T cells, and a strategy to reprogram the desmoplastic tumor microenvironment (TME) would be needed to break tolerance to these pancreatic cancers. As a proof-of-concept, we investigated the efficacy of combined DC vaccination with CD40-agonistic antibodies in a poorly immunogenic murine model of PDAC. Based on the rationale that mesothelioma and pancreatic cancer share a number of tumor associated antigens, the DCs were loaded with either pancreatic or mesothelioma tumor lysates. METHODS: Immune-competent mice with subcutaneously or orthotopically growing KrasG12D/+;Trp53R172H/+;Pdx-1-Cre (KPC) PDAC tumors were vaccinated with syngeneic bone marrow-derived DCs loaded with either pancreatic cancer (KPC) or mesothelioma (AE17) lysate and consequently treated with FGK45 (CD40 agonist). Tumor progression was monitored and immune responses in TME and lymphoid organs were analyzed using multicolor flow cytometry and NanoString analyzes. RESULTS: Mesothelioma-lysate loaded DCs generated cross-reactive tumor-antigen-specific T-cell responses to pancreatic cancer and induced delayed tumor outgrowth when provided as prophylactic vaccine. In established disease, combination with stimulating CD40 antibody was necessary to improve survival, while anti-CD40 alone was ineffective. Extensive analysis of the TME showed that anti-CD40 monotherapy did improve CD8 +T cell infiltration, but these essential effector cells displayed hallmarks of exhaustion, including PD-1, TIM-3 and NKG2A. Combination therapy induced a strong change in tumor transcriptome and mitigated the expression of inhibitory markers on CD8 +T cells. CONCLUSION: These results demonstrate the potency of DC therapy in combination with CD40-stimulation for the treatment of pancreatic cancer and provide directions for near future clinical trials

Inhibition of PRMT3 activity selectively prevents LXR-driven transcription of hepatic lipogenic genes in vivo

Agonists for the liver X receptor (LXR) are considered promising therapeutic moieties in cholesterol-driven diseases by promoting cellular cholesterol efflux. However, current clinical application of these agents is hampered by the concomitant LXR-induced activation of a lipogenic transcriptional network, leading to hepatic steatosis. Recent studies have suggested that protein arginine methyltransferase 3 (PRMT3) may act as a selective co-activator of LXR activity. Here we verified the hypothesis that PRMT3 inhibition selectively disrupts the ability of LXR to stimulate lipogenesis, while maintaining the capacity of LXR to modulate cholesterol homeostasis.A combination of the LXR agonist T0901317 and palm oil was administered to C57BL/6 mice to maximally stimulate LXR and PRMT3 activity, in absence and presence of the allosteric PRMT3 inhibitor SGC707.Treatment with the PRMT3 inhibitor SGC707 did not negatively influence the T0901317/palm oil induced upregulation of the cholesterol efflux genes ABCA1 and ABCG1 in peritoneal cells. In contrast, SGC707 treatment was associated with a significant decrease in the hepatic expression of the lipogenic gene FAS (-64%; pobstruction of lipogenic gene transcription coincided with a significant 2.3-fold (ptriglyceride content as compared to the T0901317 and palm oil treated control group.Inhibition of PRMT3 activity by SGC707 treatment selectively impairs LXR-driven transcription of hepatic lipogenic genes, while the positive effect of LXR stimulation on cholesterol efflux pathways is maintained.Biopharmaceutic

Dysesthesia after endodontic treatment

Whenever there is a close relationship between radix of mandibular teeth and inferior alveolar nerve (IAN), the IAN may be at risk during endodontic therapy. Overinstrumentation, overfilling irrigation fluids, as well as spread of infection, are the known causes of IAN damage. The following article regards two cases of IAN damage following endodontic therapy. In one case, surgical decompression with the use of piezosurgical techniques (Piezomed®) was performed, after which the pain and dysesthesia gradually subsided over the weeks following surgery. The second case was managed with medication only; the complaints reduced within 3 months. It is important to treat IAN damage as early as possible to achieve the best outcome

Inhibition of protein arginine methyltransferase 3 activity selectively impairs liver X receptor-driven transcription of hepatic lipogenic genes in vivo

Agonists for the liver X receptor (LXR) are considered promising therapeutic moieties in cholesterol-driven diseases by promoting cellular cholesterol efflux pathways. However, current clinical application of these agents is hampered by concomitant LXR-induced activation of a lipogenic transcriptional network, leading to hepatic steatosis. Recent studies have suggested that protein arginine methyltransferase 3 (PRMT3) may act as a selective co-activator of LXR activity. Here, we verified the hypothesis that PRMT3 inhibition selectively disrupts the ability of LXR to stimulate lipogenesis while maintaining its capacity to modulate macrophage cholesterol homeostasis. A combination of the LXR agonist T0901317 and palm oil was administered to C57BL/6 mice to maximally stimulate LXR and PRMT3 activity. PRMT3 activity was inhibited using the allosteric inhibitor SGC707. Treatment with SGC707 did not negatively influence the T0901317/palm oil-induced up-regulation of the cholesterol efflux ATP-binding cassette transporter genes, ABCA1 and ABCG1, in peritoneal cells. In contrast, SGC707 treatment was associated with a significant decrease in the hepatic expression of the lipogenic gene fatty acid synthase (-64%). A similar trend was observed for stearoyl-coenzyme A desaturase and acetyl CoA carboxylase expression (-43%; -56%). This obstruction of lipogenic gene transcription coincided with a significant 2.3-fold decrease in liver triglyceride content as compared with the T0901317 and palm oil-treated control group. We showed that inhibition of PRMT3 activity by SGC707 treatment selectively impairs LXR-driven transcription of hepatic lipogenic genes, while the positive effect of LXR stimulation on macrophage cholesterol efflux pathways is maintained.Biopharmaceutic