Neoadjuvant Use of Oncolytic Herpes Virus G47? Enhances the Antitumor Efficacy of Radiofrequency Ablation
ABSTRACT: G47? is a triple-mutated oncolytic herpes simplex virus type 1 designed to induce antitumor immune responses efficiently. We examine the usefulness of G47? as a neoadjuvant therapy for radiofrequency ablation (RFA), a standard local treatment for certain cancers such as liver cancer, but remote recurrences within the same organ often occur. In A/J mice harboring bilateral subcutaneous Neuro2a tumors, the left tumors were treated with G47? intratumoral injections followed by RFA. Whereas the RFA-treated tumors were all eradicated, the growth of the right tumors was evaluated and tumor-infiltrating lymphocytes were analyzed. The G47?+RFA treatment caused smaller volumes of right tumors, accompanied by increased CD8+/CD45+ T cells, compared with G47? monotherapy. After depletion of CD8+ T cells, the enhanced efficacy on the contralateral tumors was completely abolished. Neoadjuvant G47? led to rejection of rechallenged tumors, which was caused by efficient induction of specific antitumor immune responses shown by enzyme-linked immunospot (ELISPOT) assays. Treatment of tumor-harboring animals with an anti-programmed cell death 1 ligand 1 (PD-L1) antibody led to even greater efficacy on contralateral tumors. Our study indicates that the neoadjuvant use of G47? effectively enhances the efficacy of RFA via CD8+ T cell-dependent immunity that is further augmented by an immune checkpoint inhibitor. Graphical Abstract Radiofrequency ablation (RFA) is an effective local treatment, but remote recurrences often occur. In immunocompetent mice harboring bilateral subcutaneous tumors, treatment with oncolytic herpes G47? prior to RFA causes enhanced efficacy on remote tumors with increased immune responses, further boosted by following with anti-PD-L1 antibody. Such sequential treatments should be useful.
Project description:While surgical resection is a cornerstone of cancer treatment, local and distant recurrences continue to adversely affect outcome in a significant proportion of patients. Evidence that an alternative debulking strategy involving radiofrequency ablation (RFA) induces antitumor immunity prompted the current investigation of the efficacy of performing RFA prior to surgical resection (pre-resectional RFA) in a preclinical mouse model.Therapeutic efficacy and systemic immune responses were assessed following pre-resectional RFA treatment of murine CT26 colon adenocarcinoma.Treatment with pre-resectional RFA significantly delayed tumor growth and improved overall survival compared to sham surgery, RFA, or resection alone. Mice in the pre-resectional RFA group that achieved a complete response demonstrated durable antitumor immunity upon tumor re-challenge. Failure to achieve a therapeutic benefit in immunodeficient mice confirmed that tumor control by pre-resectional RFA depends on an intact adaptive immune response rather than changes in physical parameters that make ablated tumors more amenable to a complete surgical excision. RFA causes a marked increase in intratumoral CD8+ T lymphocyte infiltration, thus substantially enhancing the ratio of CD8+ effector T cells: FoxP3+ regulatory T cells. Importantly, pre-resectional RFA significantly increases the number of antigen-specific CD8+ T cells within the tumor microenvironment and tumor-draining lymph node but had no impact on infiltration by myeloid-derived suppressor cells, M1 macrophages or M2 macrophages at tumor sites or in peripheral lymphoid organs (i.e., spleen). Finally, pre-resectional RFA of primary tumors delayed growth of distant tumors through a mechanism that depends on systemic CD8+ T cell-mediated antitumor immunity.Improved survival and antitumor systemic immunity elicited by pre-resectional RFA support the translational potential of this neoadjuvant treatment for cancer patients with high-risk of local and systemic recurrence.
Project description:Purpose: The aim of this study is to investigate whether radiofrequency ablation (RFA) improves the efficacy of adoptive T cell immunotherapy in preclinical mouse cancer models.Method: Mice implanted subcutaneously (sc) with syngeneic colon adenocarcinoma or melanoma were treated with sub-curative in situ RFA (90?°C, 1?min). Trafficking of T cells to lymph nodes (LN) or tumors was quantified by homing assays and intravital microscopy (IVM) after sham procedure or RFA. Expression of trafficking molecules (CCL21 and intercellular adhesion molecule-1 [ICAM-1]) on high endothelial venules (HEV) in LN and tumor vessels was evaluated by immunofluorescence microscopy. Tumor-bearing mice were pretreated with RFA to investigate the therapeutic benefit when combined with adoptive transfer of in vitro-activated tumor-specific CD8+ T cells.Results: RFA increased trafficking of naïve CD8+ T cells to tumor-draining LN (TdLN). A corresponding increase in expression of ICAM-1 and CCL21 was detected on HEV in TdLN but not in contralateral (c)LN. IVM revealed that RFA substantially enhanced secondary firm arrest of lymphocytes selectively in HEV in TdLN. Furthermore, strong induction of ICAM-1 in tumor vessels was associated with significantly augmented trafficking of adoptively transferred in vitro-activated CD8+ T cells to tumors after RFA. Finally, preconditioning tumors with RFA augmented CD8+ T cell-mediated apoptosis of tumor targets and delayed growth of established tumors when combined with adoptive T cell transfer immunotherapy.Conclusions: These studies suggest that in addition to its role as a palliative therapeutic modality, RFA may have clinical potential as an immune-adjuvant therapy by augmenting the efficacy of adoptive T cell therapy.
Project description:Radiofrequency ablation (RFA) is an effective local therapy approach for treating solitary tumor of many types of malignancy. The impact of RFA on the tumor immune microenvironment on distant tumors after RFA treatment is still unclear. In this study, by using syngeneic tumor models and single-cell RNA and T-cell receptor sequencing, we have investigated the alterations of tumor-infiltrating immune cells in distant non-RFA tumors. Single-cell RNA sequencing identified six distinct lymphoid clusters, five distinct monocyte/macrophage clusters, three dendritic cells clusters, and one cluster of neutrophils. We found that RFA treatment reduced the proportions of immunosuppressive cells including regulatory T cells, tumor-associated macrophages and tumor-associated neutrophils, whereas increased the percentages of functional T cells in distant non-RFA tumors. Moreover, RFA treatment also altered gene expressions in single-cell level in each cell cluster. By using pseudo-time analysis, we have described the biological processes of tumor-infiltrating CD8+ T cells and monocytes/macrophages based on the transcriptional profiles. In addition, the immune checkpoints including PD-1 and LAG3 were upregulated in the T cells in distant non-RFA tumors after RFA treatment. In conclusion, our data indicate that RFA treatment induced remodeling of tumor immune microenvironment in distant non-RFA tumors in pancreatic cancer mouse model and suggest that combining RFA with immune checkpoint inhibitors may be an effective treatment approach.
Project description:Radiofrequency ablation (RFA) has been shown to elicit tumor-specific T-cell immune responses, but is not sufficient to prevent cancer progression. Here, we investigated immune-suppressive mechanisms limiting the efficacy of RFA.We performed a retrospective case-controlled study on patients with synchronous colorectal cancer liver metastases who had received primary tumor resection with or without preoperative RFA for liver metastases. Tumor-infiltrating T cells and tumoral PD-L1 expression in human colorectal cancer tissues were analyzed by immunohistochemistry. T-cell immune responses and PD-1/PD-L1 expression were also characterized in an RFA mouse model. In addition, the combined effect of RAF and PD-1 blockade was evaluated in the mouse RFA model.We found that RFA treatment of liver metastases increased not only T-cell infiltration, but also PD-L1 expression in primary human colorectal tumors. Using mouse tumor models, we demonstrated that RFA treatment of one tumor initially enhanced a strong T-cell-mediated immune response in tumor. Nevertheless, tumor quickly overcame the immune responses by inhibiting the function of CD8(+) and CD4(+) T cells, driving a shift to higher regulatory T-cell to Teff ratio, and upregulating PD-L1/PD-1 expression. Furthermore, we established that the combined therapy of RFA and anti-PD-1 antibodies significantly enhanced T-cell immune responses, resulting in stronger antitumor immunity and prolonged survival.The PD-L1-PD-1 axis plays a critical role in dampening RFA-induced antitumor immune responses, and this study provides a strong rationale for combining RFA and the PD-L1/PD-1 blockade in the clinical setting.
Project description:AIMS: In this article we present our experience with radiofrequency ablation (RFA) in the treatment of 105 renal tumors. MATERIALS AND METHODS: RFA was performed on 105 renal tumors in 97 patients, with a mean tumor size of 32 mm (11-68 mm). The mean patient age was 71.7 years (range, 36-89 years). The ablations were carried out under ultrasound (n = 43) or CT (n = 62) guidance. Imaging follow-up was by contrast-enhanced CT within 10 days and then at 6-monthly intervals. Multivariate analysis was performed to determine variables associated with procedural outcome. RESULTS: Eighty-three tumors were completely treated at a single sitting (79%). Twelve of the remaining tumors were successfully re-treated and a clinical decision was made not to re-treat seven patients. A patient with a small residual crescent of tumor is under follow-up and may require further treatment. In another patient, re-treatment was abandoned due to complicating pneumothorax and difficult access. One patient is awaiting further re-treatment. The overall technical success rate was 90.5%. Multivariate analysis revealed tumor size to be the only significant variable affecting procedural outcome. (p = 0.007, Pearson chi(2)) Five patients had complications. There have been no local recurrences. CONCLUSION: Our experience to date suggests that RFA is a safe and effective, minimally invasive treatment for small renal tumors.
Project description:The expanded possibilities to explore the lung deeper with new tools such as electromagnetic navigation bronchoscopy (ENB) or radial probe endobronchial ultrasonography (radial EBUS), combined with miniaturization of traditional local therapies such as radiofrequency ablation (RFA), radiotherapy, cryotherapy or photodynamic therapy, let the bronchoscopists hope for new ways of endoscopic treatments. This challenge could change the practice in the upcoming decades but raise some physical and technical issues. Safety and efficacy need to be solidly established to face the serious concurrence of stereotactic radiotherapy (SBRT) or percutaneous RFA. Here we describe ongoing development and perspectives for endobronchial treatment of peripheral lung tumors.
Project description:BACKGROUNDS: Malignant peripheral nerve sheath tumors (MPNSTs) are an aggressive and often lethal sarcoma that frequently develops in patients with neurofibromatosis type 1 (NF1). We developed new preclinical MPNST models and tested the efficacy of oncolytic herpes simplex viruses (oHSVs), a promising cancer therapeutic that selectively replicates in and kills cancer cells. METHODS: Mouse NF1(-) MPNST cell lines and human NF1(-) MPNST stemlike cells (MSLCs) were implanted into the sciatic nerves of immunocompetent and athymic mice, respectively. Tumor growth was followed by external measurement and sciatic nerve deficit using a hind-limb scoring system. Oncolytic HSV G47? as well as "armed" G47? expressing platelet factor 4 (PF4) or interleukin (IL)-12 were injected intratumorally into established sciatic nerve tumors. RESULTS: Mouse MPNST cell lines formed tumors with varying growth kinetics. A single intratumoral injection of G47? in sciatic nerve tumors derived from human S462 MSLCs in athymic mice or mouse M2 (37-3-18-4) cells in immunocompetent mice significantly inhibited tumor growth and prolonged survival. Local IL-12 expression significantly improved the efficacy of G47? in syngeneic mice, while PF4 expression prolonged survival. Injection of G47? directly into the sciatic nerve of athymic mice resulted in only mild symptoms that did not differ from phosphate buffered saline control. CONCLUSIONS: Two new orthotopic MPNST models are described, including in syngeneic mice, expanding the options for preclinical testing. Oncolytic HSV G47? exhibited robust efficacy in both immunodeficient and immunocompetent MPNST models while maintaining safety. Interleukin-12 expression improved efficacy. These studies support the clinical translation of G47? for patients with MPNST.
Project description:Local recurrence is a therapeutic challenge for radiofrequency ablation (RFA) in treatment of small solid focal malignancies. Here we show that RFA induced heat shock proteins (HSPs) expression and high mobility group box-1 (HMGB1) translocation in xenografted melanoma, which might create a proinflammatory microenvironment that favors tumor antigen presentation and activation of the effector T cells. On this basis, we investigate whether a prime-boost strategy combining a prime with heat-shocked tumor cell lysate-pulsed dendritic cell (HT-DC) followed by an in situ boost with radiofrequency thermal ablation can prevent local tumor recurrence. The combination treatment with HT-DC and RFA showed potent antitumor effects, with >or=90% of tumor recurrence abrogated following RFA treatment. By contrast, prevaccination with unheated tumor lysate-pulsed DC had little effect on tumor relapse. Analysis of the underlying mechanism revealed that splenocytes from mice treated with HT-DC plus RFA contained significantly more tumor-specific, IFN-gamma-secreting T cells compared with control groups. Moreover, adoptive transfer of splenocytes from successfully treated tumor-free mice protected naive animals from tumor recurrence following RFA, and this was mediated mainly by CD8(+) T cells. Therefore, the optimal priming for the DC vaccination before RFA is important for boosting antigen-specific T cell responses and prevention of cancer recurrence.
Project description:OBJECTIVES: To evaluate the efficacy and safety of radiofrequency ablation (RFA) versus hepatic resection (HR) for early hepatocellular carcinoma (HCC) meeting the Milan criteria. METHODS: A meta-analysis was conducted, and PubMed, Web of Science, the Cochrane Library, CBM, CNKI and VIP databases were systematically searched through November 2012 for randomized and nonrandomized controlled trials (RCTs and NRCTs). The Cochrane Collaboration's tool and modified MINORS score were applied to assess the quality of RCTs and NRCTs, respectively. The GRADE approach was employed to evaluate the strength of evidence. RESULTS: Three RCTs and twenty-five NRCTs were included. Among 11,873 patients involved, 6,094 patients were treated with RFA, and 5,779 with HR. The pooled results of RCTs demonstrated no significant difference between groups for 1- and 3-year overall survival (OS), recurrence-free survival (RFS) and disease-free survival (DFS) (p>0.05). The 5-year OS (Relative Risk, RR 0.72, 95% CI 0.60 to 0.88) and RFS (RR 0.56, 95% CI 0.40 to 0.78) were lower with RFA than with HR. The 3- and 5-year recurrences with RFA were higher than with HR (RR 1.48, 95% CI 1.14 to 1.94, and RR 1.52, 95% CI 1.18 to 1.97, respectively), but 1-year recurrence and in-hospital mortality showed no significant differences between groups (p>0.05). The complication rate (RR 0.18, 95% CI 0.06 to 0.53) was lower and hospital stays (Mean difference -8.77, 95% CI -10.36 to -7.18) were shorter with RFA than with HR. The pooled results of NRCTs showed that the RFA group had lower 1-, 3- and 5-year OS, RFS and DFS, and higher recurrence than the HR group (p<0.05). But for patients with very early stage HCC, RFA was comparable to HR for OS and recurrence. CONCLUSION: The effectiveness of RFA is comparable to HR, with fewer complications but higher recurrence, especially for very early HCC patients.
Project description:Advanced gastric cancer, especially scirrhous gastric cancer with peritoneal dissemination, remains refractory to conventional therapies. G47?, a third-generation oncolytic herpes simplex virus type 1, is an attractive novel therapeutic agent for solid cancer. In this study, we investigated the therapeutic potential of G47? for human gastric cancer. In vitro, G47? showed good cytopathic effects and replication capabilities in nine human gastric cancer cell lines tested. In vivo, intratumoral inoculations with G47? (2 × 105 or 1 × 106 plaque-forming units [PFU]) significantly inhibited the growth of subcutaneous tumors (MKN45, MKN74, and 44As3). To evaluate the efficacy of G47? for advanced-stage models of gastric cancer, we generated an orthotopic tumor model and peritoneal dissemination models of human scirrhous gastric cancer (MKN45-luc and 44As3Luc), which have features mimicking intractable scirrhous cancer patients. G47? (1 × 106 PFU) was constantly efficacious whether administered intratumorally or intraperitoneally in the clinically relevant models. Notably, G47? injected intraperitoneally readily distributed to, and selectively replicated in, disseminated tumors. Furthermore, flow cytometric analyses of tumor-infiltrating cells in subcutaneous tumors revealed that intratumoral G47? injections markedly decreased M2 macrophages while increasing M1 macrophages and natural killer (NK) cells. These findings indicate the usefulness of G47? for treating human gastric cancer, including scirrhous gastric cancer and the ones in advanced stages.