Therapeutic Vaccination against A Modified Minimal Survivin Epitope Induces Functional CD4 T Cells That Recognize Survivin-Expressing Cells

T cell receptor therapy against melanoma-Immunotherapy for the future?

Malignant melanoma has seen monumental changes in treatment options the last decade from the very poor results of dacarbazine treatment to the modern-day use of targeted therapies and immune checkpoint inhibitors. Melanoma has a high mutational burden making it more capable of evoking immune responses than many other tumours. Even when considering double immune checkpoint blockade with anti-CTLA-4 and anti-PD-1, we still have far to go in melanoma treatment as 50% of patients with metastatic disease do not respond to current treatment. Alternative immunotherapy should therefore be considered. Since melanoma has a high mutational burden, it is considered more immunogenic than many other tumours. T cell receptor (TCR) therapy could be a possible way forward, either alone or in combination, to improve the response rates of this deadly disease. Melanoma is one of the cancers where TCR therapy has been frequently applied. However, the number of antigens targeted remains fairly limited, although advanced personalized therapies aim at also targeting private mutations. In this review, we look at possible aspects of targeting TCR therapy towards melanoma and provide an implication of its use in the future.

Novel Apoptosis-Inducing Agents for the Treatment of Cancer, a New Arsenal in the Toolbox

Evasion from apoptosis is an important hallmark of cancer cells. Alterations of apoptosis pathways are especially critical as they confer resistance to conventional anti-cancer therapeutics, e.g., chemotherapy, radiotherapy, and targeted therapeutics. Thus, successful induction of apoptosis using novel therapeutics may be a key strategy for preventing recurrence and metastasis. Inhibitors of anti-apoptotic molecules and enhancers of pro-apoptotic molecules are being actively developed for hematologic malignancies and solid tumors in particular over the last decade. However, due to the complicated apoptosis process caused by a multifaceted connection with cross-talk pathways, protein–protein interaction, and diverse resistance mechanisms, drug development within the category has been extremely challenging. Careful design and development of clinical trials incorporating predictive biomarkers along with novel apoptosis-inducing agents based on rational combination strategies are needed to ensure the successful development of these molecules. Here, we review the landscape of currently available direct apoptosis-targeting agents in clinical development for cancer treatment and update the related biomarker advancement to detect and validate the efficacy of apoptosis-targeted therapies, along with strategies to combine them with other agents.

Transient redirection of T cells for adoptive cell therapy with telomerase-specific T helper cell receptors isolated from long term survivors after cancer vaccination

Adoptive cell therapy (ACT) with retargeted T cells has produced remarkable clinical responses against cancer, but also serious toxicity. Telomerase is overexpressed in most cancers, but also expressed in some normal cells, raising safety concerns. We hypothesize that ACT with T-helper cell receptors may overcome tumour tolerance, mobilize host immune cells and induce epitope spreading, with limited toxicity. From long term survivors after cancer vaccination, we have isolated telomerase-specific T cell receptors (TCRs) from T-helper cells. Herein, we report the development of transient retargeting of T cells with mRNA-based TCRs. This strategy allows for safer clinical testing and meaningful dose escalation. DP4 is the most common HLA molecule. We cloned two telomerase-specific, DP4-restricted TCRs into the mRNA expression vector pCIpA102, together with the sorter/marker/suicide gene RQR8. Donor T cells were electroporated with mRNA encoding TCR_RQR8. The results showed that both TCR_RQR8 constructs were expressed in >90% of T cells. The transfected T cells specifically recognized the relevant peptide, as well as naturally processed epitopes from a 177aa telomerase protein fragment, and remained functional for six days. A polyfunctional and Th1-like cytokine profile was observed. The TCRs were functional in both CD4+and CD8+recipient T cells, even though DP4-restricted. The findings demonstrate that the cloned TCRs confer recipient T cells with the desired telomerase-specificity and functionality. Preclinical experiments may provide limited information on the efficacy and toxicity of T-helper TCRs, as these mobilize the host immune system. We therefore intend to use the mRNA-based TCRs for a first-in-man trial.

Survivin-peptide vaccination elicits immune response after allogeneic nonmyeloablative transplantation: a safe strategy to enhance the graft versus tumor effect

Allogeneic hematopoietic cell transplantation (allo-HCT) is an adoptive immunotherapy strategy whose effectiveness relies on graft-versus-tumor (GVT) effect. We explored the feasibility of enhancing GVT after allo-HCT by peptide vaccination. Two myeloma patients were transplanted with a fludarabine-total body irradiation conditioning regimen and vaccinated with an HLA-A*0201-restricted modified survivin nonapeptide, plus montanide as adjuvant. At time of first vaccination, one patient had just attained serological remission despite documented relapse after transplant, while the other patient was in stable disease. Both patients had an immune response to vaccination: the frequency of survivin-specific CD8⁺ T cells increased between second and sixth vaccination and accounted for 0.5-0.8% of CD8⁺ cells; CD8⁺ cells were functional in ELISPOT assay. The first patient persists in complete remission with a follow-up of >5 years, while the second patient did not have a clinical response and vaccination was halted. We analyzed the T-cell receptor (TCR) repertoire of the first patient by spectratyping and found that vaccination did not affect the diversity of TCR profile, indicating that survivin clonotypes were probably spread in multiple TCR families. We generated a limited number (n = 4) of survivin-specific T cell clones: three were reactive only against the modified peptide, whereas one clone recognized also the naive peptide. Peptide vaccination is safe and applicable after allo-HCT and elicits an efficient antigen-specific T cell response without causing graft-versus-host disease.

Survivin Monoclonal Antibodies Detect Survivin Cell Surface Expression and Inhibit Tumor Growth In Vivo

Purpose: Survivin is an inhibitor of apoptosis protein (IAP) that is highly expressed in many cancers and represents an attractive molecule for targeted cancer therapy. Although primarily regarded as an intracellular protein with diverse actions, survivin has also been identified in association with circulating tumor exosomes.Experimental Design: We have reported that active, specific vaccination with a long peptide survivin immunogen leads to the development of survivin-specific CD8-mediated tumor cell lysis and prolongation of survival in tumor-bearing mice. In addition to cellular antitumor responses, circulating anti-survivin antibodies are detected in the serum of mice and human glioblastoma patients following vaccination with the survivin immunogen.Results: Here we demonstrate that survivin is present on the outer cell membrane of a wide variety of cancer cell types, including both murine and human glioma cells. In addition, antibodies to survivin that are derived from the immunogen display antitumor activity against murine GL261 gliomas in both flank and intracranial tumor models and against B16 melanoma as well.Conclusions: In addition to immunogen-induced, CD8-mediated tumor cell lysis, antibodies to the survivin immunogen have antitumor activity in vivo Cell-surface survivin could provide a specific target for antibody-mediated tumor immunotherapeutic approaches. Clin Cancer Res; 24(11); 2642-52. ©2018 AACR.

Indoleamine 2,3-dioxygenase and survivin peptide vaccine combined with temozolomide in metastatic melanoma

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) and survivin have been identified as potential targets for cancer vaccination. In this phase II study a vaccine using the peptides Sur1M2 and IDO5 was combined with the chemotherapy temozolomide (TMZ) for treatment of metastatic melanoma patients. The aim was to simultaneously target several immune inhibiting mechanisms and the highly malignant cells expressing survivin.

METHODS

HLA-A2 positive patients with advanced malignant melanoma were treated biweekly with 150 mg/m² TMZ daily for 7 days followed by subcutaneous vaccination with 250 µg of each peptide in 500 µL Montanide solution at day 8. Granulocyte-macrophage colony-stimulating factor was used as an adjuvant and topical imiquimod was applied prior to vaccination. Treatment was continued until disease progression. Clinical response was evaluated by PET-CT and immunological outcome was assessed by ELISPOT and flow cytometry.

RESULTS

In total, 17 patients were treated with a clinical benefit rate of 18% including one patient with partial tumor regression. Immune analyses revealed a vaccine specific response in 8 (67%) of 12 patients tested, a significant decrease in the frequency of CD4+ T-cells during treatment, a tendency towards decreasing frequencies of naïve CD4+ and CD8+ T-cells, and increasing frequencies of memory CD4+ and CD8+ T-cells.

CONCLUSIONS

These results demonstrate that vaccine-induced immunity towards survivin and IDO-derived peptides can be achieved in combination with TMZ in patients mainly suffering from grade M1c melanoma including patients with brain metastases. A significant clinical activity could not be proven in this small study and a larger setup is needed to properly assess clinical efficacy.

Survivin in autoimmune diseases

Survivin is a protein functionally important for cell division, apoptosis, and possibly, for micro-RNA biogenesis. It is an established marker of malignant cell transformation. In non-malignant conditions, the unique properties of survivin make it indispensable for homeostasis of the immune system. Indeed, it is required for the innate and adaptive immune responses, controlling differentiation and maintenance of CD4⁺ and CD8⁺ memory T-cells, and in B cell maturation. Recently, survivin has emerged as an important player in the pathogenesis of autoimmune diseases. Under the conditions of unreserved inflammation, survivin enhances antigen presentation, maintains persistence of autoreactive cells, and supports production of autoantibodies. In this context, survivin takes its place as a diagnostic and prognostic marker in rheumatoid arthritis, psoriasis, systemic sclerosis and pulmonary arterial hypertension, neuropathology and multiple sclerosis, inflammatory bowel diseases and oral lichen planus. In this review, we summarise the knowledge about non-malignant properties of survivin and focus on its engagement in cellular and molecular pathology of autoimmune diseases. The review highlights utility of survivin measures for clinical applications. It provides rational for the survivin inhibiting strategies and presents results of recent reports on survivin inhibition in modern therapies of cancers and autoimmune diseases.