Phase I clinical trial of human vascular endothelial growth factor receptor 1 peptide vaccines for patients with metastatic renal cell carcinoma

Randomized phase I/II study of vascular endothelial growth factor receptor peptide vaccines for patients with hepatocellular carcinoma

AIM

We evaluated the safety and efficacy of vascular endothelial growth factor receptor (VEGFR)-targeted peptide vaccines for the immunization of patients with unresectable hepatocellular carcinoma (HCC) who had responded to transarterial chemoembolization.

METHODS

Twenty-two patients were randomized 1:1 to receive VEGFR-targeted peptides or placebo. The primary end-point was the safety assessment of the immunization. The secondary end-points were evaluation of immunological responses and clinical outcomes.

RESULTS

No severe adverse events were induced by the study agents. Among the 12 patients in the vaccine group, a VEGFR1-specific cytotoxic T lymphocyte (CTL) response was induced in eight (66.7%) patients and a VEGFR2-specific CTL response was induced in 10 (83.3%). The median progression-free survival (PFS) and overall survival (OS) rates were 4.8 and 52.0 months, respectively, in the vaccine group, and 2.7 and 21.8 months, respectively, in the placebo group. No statistically significant differences were found between the two groups (PFS p = 0.925, OS p = 0.190). When divided into two groups according to immunoreactivity, the median PFS of patients with and without a strong immune response to VEGFR1 were 7.4 and 2.7 months, and that to VEGFR2 were 10.6 and 2.7 months, respectively; there were significant differences according to the immune response.

CONCLUSIONS

Immunotherapy with peptide vaccines targeting VEGFR1 and VEGFR2 was well tolerated with no serious adverse events. It also effectively induced peptide-specific CTLs in patients with unresectable HCC.

Nanoliposomal VEGF-R2 peptide vaccine acts as an effective therapeutic vaccine in a murine B16F10 model of melanoma

Background

The vascular endothelial growth factor receptor-2 (VEGFR-2) plays an important role in melanoma development and progression. Peptide vaccines have shown great potential in cancer immunotherapy by targeting VEGFR-2 as a tumor-associated antigen and boosting the immune response against both tumor cells and tumor endothelial cells. Despite this, the low efficiency of peptide vaccines has resulted in moderate therapeutic results in the majority of studies. Enhancing the delivery of peptide vaccines using nanoliposomes is an important strategy for improving the efficacy of peptide vaccines. In this regard, we designed VEGFR-2-derived peptides restricted to both mouse MHC I and human HLA-A*02:01 using immunoinformatic tools and selected three peptides representing the highest binding affinities. The peptides were encapsulated in nanoliposomal formulations using the film method plus bath sonication and characterized for their colloidal properties.

Results

The mean diameter of peptide-encapsulated liposomes was around 135 nm, zeta potential of - 17 mV, and encapsulation efficiency of approximately 70%. Then, vaccine formulations were injected subcutaneously in mice bearing B16F10-established melanoma tumors and their efficiency in triggering immunological, and anti-tumor responses was evaluated. Our results represented that one of our designed VEGFR-2 peptide nanoliposomal formulations (Lip-V1) substantially activated CD4+ (p < 0.0001) and CD8+ (P < 0.001) T cell responses and significantly boosted the production of IFN-γ (P < 0.0001) and IL-4 (P < 0.0001). Furthermore, this formulation led to a significant decrease in tumor volume (P < 0.0001) and enhanced survival (P < 0.05) in mice.

Conclusion

Our findings suggest that the nanoliposomal formulation containing VEGFR-2 peptides could be a promising therapeutic vaccination approach capable of eliciting strong antigen-specific immunologic and anti-tumor responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12645-023-00213-7.

Application of VEGF/VEGFR peptide vaccines in cancer: a systematic review of clinical trials

Peptide vaccines that target vascular endothelial growth factor (VEGF) pathway have shown promising results in inducing strong anti-tumor immune responses with minimal toxicity in various clinical studies. This systematic review was conducted to provide a comprehensive evaluation of the therapeutic efficacy, immune response, survival rate, and side effects of VEGF/VEGF receptor-based peptide vaccines. VEGF/VEGFR2 peptide vaccines were found to be safe and effective in inducing anti-tumor immune responses, while induced moderate clinical benefit. In this regard, further clinical trials are necessary to fully evaluate their clinical effects and the exact correlation between induction of immune response and clinical outcomes.

The Changing Landscape of Immunotherapy for Advanced Renal Cancer

The management of advanced renal cell carcinoma has advanced tremendously over the past decade, but most patients still do not receive durable clinical benefit from current therapies. Renal cellcarcinoma is an immunogenic tumor, historically with conventional cytokine therapies, such as interleukin-2 and interferon-α, and contemporarily with the introduction of immune checkpoint inhibitors. Now the central therapeutic strategy in renal cell carcinoma is combination therapies including immunecheckpoint inhibitors. In this Review, we look back on the historical changes in systemic therapy for advanced renal cell carcinoma, and focus on the latest developments and prospects in this field.

Tumor microenvironment antigens

The identification and characterization of tumor antigens are central objectives in developing anti-cancer immunotherapy. Traditionally, tumor-associated antigens (TAAs) are considered relatively restricted to tumor cells (i.e., overexpressed proteins in tumor cells), whereas tumor-specific antigens (TSAs) are considered unique to tumor cells. Recent studies have focused on identifying patient-specific neoantigens, which might be highly immunogenic because they are not expressed in normal tissues. The opposite strategy has emerged with the discovery of anti-regulatory T cells (anti-Tregs) that recognize and attack many cell types in the tumor microenvironment, such as regulatory immune cells, in addition to tumor cells. The term proposed in this review is "tumor microenvironment antigens" (TMAs) to describe the antigens that draw this attack. As therapeutic targets, TMAs offer several advantages that differentiate them from more traditional tumor antigens. Targeting TMAs leads not only to a direct attack on tumor cells but also to modulation of the tumor microenvironment, rendering it immunocompetent and tumor-hostile. Of note, in contrast to TAAs and TSAs, TMAs also are expressed in non-transformed cells with consistent human leukocyte antigen (HLA) expression. Inflammation often induces HLA expression in malignant cells, so that targeting TMAs could additionally affect tumors with no or very low levels of surface HLA expression. This review defines the characteristics, differences, and advantages of TMAs compared with traditional tumor antigens and discusses the use of these antigens in immune modulatory vaccines as an attractive approach to immunotherapy. Different TMAs are expressed by different cells and could be combined in anti-cancer immunotherapies to attack tumor cells directly and modulate local immune cells to create a tumor-hostile microenvironment and inhibit tumor angiogenesis. Immune modulatory vaccines offer an approach for combinatorial therapy with additional immunotherapy including checkpoint blockade, cellular therapy, or traditional cancer vaccines. These combinations would increase the number of patients who can benefit from such therapeutic measures, which all have optimal efficiency in inflamed tumors.

Vaccines targeting angiogenesis in melanoma

Angiogenesis has a significant role in metastasis and progression of melanoma. Even small tumors may be susceptible to metastasis and hence lead to a worse outcome in patients with melanoma. One of the anti-angiogenic treatment approaches that is undergoing comprehensive study is specific immunotherapy. While tumor cells are challenging targets for immunotherapy due to their genetic instability and heterogeneity, endothelial cells (ECs) are genetically stable. Therefore, vaccines targeting angiogenesis in melanoma are appropriate choices that target both tumor cells and ECs while capable of inducing strong, anti-tumor immune responses with limited toxicity. The main targets of angiogenesis are VEGFs and their receptors but other potential targets have also been investigated, especially in preclinical studies. Various types of vaccines that target angiogenesis in melanoma have been studied including DNA, peptide, protein, dendritic cell-based, and endothelial cell vaccines. This review outlines a number of target antigens that are important for potential progress in developing vaccines for targeting angiogenesis in melanoma. We also discuss different types of vaccines that have been investigated, delivery mechanisms and popular adjuvants, and suggest ways to improve future clinical outcomes.

Immunoinformatics aided design of peptide-based vaccines against ebolaviruses

Ebolaviruses are at the forefront of emerging viruses and present a very perceptible threat to global peace and harmony. In the last decade, Ebola virus disease has claimed more than 90% of total lives since its inception in 1976. Owing to multiple host immune evasion methods employed by the virus and the limitations of traditional vaccine development approaches, finding a globally effective and reliable counter measure against Ebola virus remains a challenge. Highly conserved peptide fragments belonging to critical viral proteins and containing multiple epitopes which have the capacity to interact with a wide array of HLA molecules present a viable solution. Immunoinformatics or computational immunology enables rapid screening and shortlisting of plausible epitopes with a high immunogenic potential, thus, supporting expeditious elucidation of efficacious vaccine candidates. In light of above facts, we describe a computational methodology in this chapter for identification of potent peptide vaccine candidates against human infecting viruses. By applying this stringent methodology, we were able to identify multiple, immunogenic ebolavirus peptide fragments which, after verification in animal models, might be considered as part of future synthetic Ebola vaccine.

Cancer Vaccines for Genitourinary Tumors: Recent Progresses and Future Possibilities

BACKGROUND

In the last years, many new treatment options have widened the therapeutic scenario of genitourinary malignancies. Immunotherapy has shown efficacy, especially in the urothelial and renal cell carcinomas, with no particular relevance in prostate cancer. However, despite the use of immune checkpoint inhibitors, there is still high morbidity and mortality among these neoplasms. Cancer vaccines represent another way to activate the immune system. We sought to summarize the most recent advances in vaccine therapy for genitourinary malignancies with this review.

METHODS

We searched PubMed, Embase and Cochrane Database for clinical trials conducted in the last ten years, focusing on cancer vaccines in the prostate, urothelial and renal cancer.

RESULTS

Various therapeutic vaccines, including DNA-based, RNA-based, peptide-based, dendritic cells, viral vectors and modified tumor cells, have been demonstrated to induce specific immune responses in a variable percentage of patients. However, these responses rarely corresponded to significant survival improvements.

CONCLUSIONS

Further preclinical and clinical studies will improve the knowledge about cancer vaccines in genitourinary malignancies to optimize dosage, select targets with a driver role for tumor development and growth, and finally overcome resistance mechanisms. Combination strategies represent possibly more effective and long-lasting treatments.

Current status of antigen-specific T-cell immunotherapy for advanced renal-cell carcinoma

In renal-cell carcinoma (RCC), tumor-reactive T-cell responses can occur spontaneously or in response to systemic immunotherapy with cytokines and immune checkpoint inhibitors. Cancer vaccines and engineered T-cell therapies are designed to selectively augment tumor antigen-specific CD8⁺ T-cell responses with the goal to elicit tumor regression and avoid toxicities associated with nonspecific immunotherapies. In this review, we provide an overview of the central role of T-cell immunity in the treatment of advanced RCC. Clinical outcomes for antigen-targeted vaccines or other T-cell-engaging therapies for RCC are summarized and evaluated, and emerging new strategies to enhance the effectiveness of antigen-specific therapy for RCC are discussed.

Clinical and histopathological analyses of VEGF receptors peptide vaccine in patients with primary glioblastoma - a case series

BACKGROUND

The expression of vascular endothelial growth factor (VEGF)-A/ VAGF receptors (VEGFRs) signaling plays a pivotal role in the tumor angiogenesis and the development of the immunosuppressive tumor microenvironment in glioblastomas. We have previously conducted exploratory clinical studies investigating VEGFRs peptide vaccination with and without multiple glioma oncoantigens in patients with recurrent high-grade gliomas. Recently, an exploratory clinical investigation of VEGFRs peptide vaccination was conducted in patients with progressive neurofibromatosis type 2. Those studies suggested that cytotoxic T lymphocytes (CTLs) induced by the vaccination can directly kill a wide variety of cells associated with tumor growth, including tumor vessels, tumor cells, and immunosuppressive cells expressing VEGFR1 and/or 2. In the present study, synergistic activity of the combination of VEGFRs peptide vaccination with chemotherapy was evaluated.

METHODS

We performed the first clinical trial to assess VEGFR1 and 2 vaccination along with temozolomide (TMZ) -based chemoradiotherapy for the patients with primary glioblastomas. Furthermore, histopathological changes after the vaccination were evaluated using paired pre- and post- vaccination specimens.

RESULTS

The disappearance of radiographically enhanced lesion was observed in 2 patients after the vaccination, including one in which the methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter was not observed. The histopathological findings of pre- and post-vaccination specimens demonstrated that tumor vessels showed negative or slight VEGFRs expressions after the vaccination and most endothelial cells were covered with PDGFR-β-positive pericytes. Notably, CTLs induced by VEGFRs peptide vaccination attacked not only tumor vessels but also tumor cells and regulatory T cells expressing VEGFRs even in recurrent tumors.

CONCLUSIONS

VEGFR1 and 2 vaccination may have a preliminary synergistic effect when administered with TMZ. The limitation of the present study was the paucity of the number of the samples. Further studies involving more patients are warranted to confirm the findings of this study.

TRIAL REGISTRATION

This study was registered as UMIN000013381 (University Hospital Medical Information Network-Clinical Trial Registry: UMIN-CTR) on 5 March, 2014 and with the Japan Registry of Clinical Trials (jRCT) as jRCTs031180170 on 1 March, 2019.

A VEGF receptor vaccine demonstrates preliminary efficacy in neurofibromatosis type 2

The anti-VEGF antibody bevacizumab has shown efficacy for the treatment of neurofibromatosis type 2 (NF2). Theoretically, vascular endothelial growth factor receptors (VEGFRs)-specific cytotoxic T lymphocytes (CTLs) can kill both tumor vessel cells and tumor cells expressing VEGFRs. Here we show an exploratory clinical study of VEGFRs peptide vaccine in seven patients with progressive NF2-derived schwannomas. Hearing improves in 2/5 assessable patients (40%) as determined by international guidelines, with increases in word recognition scores. Tumor volume reductions of ≥20% are observed in two patients, including one in which bevacizumab had not been effective. There are no severe adverse events related to the vaccine. Both VEGFR1-specific and VEGFR2-specific CTLs are induced in six patients. Surgery is performed after vaccination in two patients, and significant reductions in the expression of VEGFRs in schwannomas are observed. Therefore, this clinical immunotherapy study demonstrates the safety and preliminary efficacy of VEGFRs peptide vaccination in patients with NF2.

The anti-vascular endothelial growth factor (VEGF) antibody bevacizumab has shown efficacy for the treatment of neurofibromatosis type 2 (NF2). Here, the authors show that VEGFRs peptide vaccination can improve hearing and reduce tumor volume in NF2 patients, including in previously bevacizumab resistant tumors.

Targeting Angiogenesis With Peptide Vaccines

Most cancer peptide vaccinations tested so far are capable of eliciting a strong immune response, but demonstrate poor clinical benefits. Since peptide vaccination is safe and well-tolerated, and several indications suggest that it has clear potential advantages over other modalities of treatment, it is important to investigate the reasons for these clinical failures. In this review, the current state of the art in targeting angiogenic proteins via peptide vaccines is presented, and the underlying reasons for both the successes and the failures are analyzed. The review highlights a number of areas critical for future success, including choice of target antigens, types of peptides used, delivery methods and use of proper adjuvants, and suggests ways to achieve better clinical results in the future.

Targeting regulatory T cells for improving cancer therapy: Challenges and prospects

OBJECTIVE

Regulatory T cells (Tregs) play a central role in immune responses to infectious agents and tumors. Paradoxically, Tregs protect self-cells from the immune response as a part of peripheral tolerance and prevents autoimmune disorders, whereas during the process of carcinogenesis, they are exploited by tumor cells for protection against antitumor immune responses. Therefore, Tregs are often considered as a major obstacle in anticancer therapy. The objective of this review is to provide a current understanding on Tregs as a potential cellular target for achieving therapeutic gain and discuss various approaches that are implicated at preclinical and clinical scenario.

RECENT FINDINGS

Several approaches like immunotherapy and adjuvant chemotherapy, which reduce Tregs population, have been found to be useful in improving local tumor control. Our recent observations with the glycolytic inhibitor, 2-deoxy-D-glucose, established as an adjuvant in radiotherapy and chemotherapy of tumors also show that potential of 2-deoxy-D-glucose to improve local tumor control is linked with its ability to reduce the Tregs pool.

CONCLUSIONS

Several published studies and emerging evidences indicate that suppression of Treg numbers, infiltration into the tumors, and function can improve the cancer therapy by enhancing the antitumor immunity.

A pilot study of peptide vaccines for VEGF receptor 1 and 2 in patients with recurrent/progressive high grade glioma

Object

Early-phase clinical studies of glioma vaccines have shown feasibility and encouraging preliminary clinical activity. A vaccine that targets tumor angiogenesis factors in glioma microenvironment has not been reported. Therefore, we performed a pilot study to evaluate the safety and immunogenicity of a novel vaccination targeting tumor angiogenesis with synthetic peptides for vascular endothelial growth factor (VEGF) receptor epitopes in patients with recurrent/progressive high grade gliomas.

Methods

Eight patients received intranodal vaccinations weekly at a dose of 2mg/kg bodyweight 8 times. T-lymphocyte responses against VEGF receptor (VEGFR) epitopes were assessed by enzyme linked immunosorbent spot assays.

Results

This treatment was well-tolerated in patients. The first four vaccines induced positive immune responses against at least one of the targeted VEGFR epitopes in the peripheral blood mononuclear cells in 87.5% of patients. The median overall survival time in all patients was 15.9 months. Two achieved progression-free status lasting at least 6 months. Two patients with recurrent GBM demonstrated stable disease. Plasma IL-8 level was negatively correlated with overall survival.

Conclusion

These data demonstrate the safety and immunogenicity of VEGFR peptide vaccines targeting tumor vasculatures in high grade gliomas.

Present status and future perspective of peptide-based vaccine therapy for urological cancer

Use of peptide‐based vaccines as therapeutics aims to elicit immune responses through antigenic epitopes derived from tumor antigens. Peptide‐based vaccines are easily synthesized and lack significant side‐effects when given in vivo. Peptide‐based vaccine therapy against several cancers including urological cancers has made progress for several decades, but there is no worldwide approved peptide vaccine. Peptide vaccines were also shown to induce a high frequency of immune response in patients accompanied by clinical efficacy. These data are discussed in light of the recent progression of immunotherapy caused by the addition of immune checkpoint inhibitors thus providing a general picture of the potential therapeutic efficacy of peptide‐based vaccines and their combination with other biological agents. In this review, we discuss the mechanism of the antitumor effect of peptide‐based vaccine therapy, development of our peptide vaccine, recent clinical trials using peptide vaccines for urological cancers, and perspectives of peptide‐based vaccine therapy.

Phase II clinical trial using novel peptide cocktail vaccine as a postoperative adjuvant treatment for surgically resected pancreatic cancer patients

We investigated peptide cocktail vaccine OCV-C01 containing epitope peptides derived from KIF20A, vascular endothelial growth factor receptor (VEGFR)1 and VEGFR2 combined with gemcitabine in the adjuvant treatment for resected pancreatic cancer patients. A single-arm multicenter phase II study was performed on 30 patients with pancreatic ductal carcinoma who underwent pancreatectomy. At each 28-day treatment cycle, patients received weekly subcutaneous injection of OCV-C01 for 48 weeks and gemcitabine was administered intravenously at 1,000 mg/m2 on days 1, 8 and 15 for 24 weeks. Patients were followed for 18 months. The primary endpoint was disease-free survival (DFS) and secondary endpoints included safety, overall survival (OS) and immunological assays on peptide-specific cytotoxic T lymphocyte (CTL) activity and KIF20A expression in resected pancreatic cancer. The median DFS was 15.8 months [95% confidence interval (CI), 11.1-20.6] and the DFS rate at 18 months was 34.6% (95% CI, 18.3-51.6). The median OS was not reached and the OS rate at 18 months was 69.0% (95% CI, 48.8-82.5). The administration of OCV-C01 was well tolerated. In the per protocol set, there were significant differences in DFS between patients with KIF20A-specific CTL responses and without (p = 0.027), and between patients with KIF20A expression and without (p = 0.014). In addition, all four patients who underwent R0 resection with KIF20A expression had no recurrence of pancreatic cancer with KIF20A-specific CTL responses. OCV-C01 combined with gemcitabine was tolerable with a median DFS of 15.8 months, which was favorable compared with previous data for resected pancreatic cancer.

Hypoxia-inducing factor (HIF)-1α-derived peptide capable of inducing cancer-reactive cytotoxic T lymphocytes from HLA-A24+ patients with renal cell carcinoma

Hypoxic tumor microenvironment makes cancer cells to be therapy-resistant and hypoxia-inducing factors (HIFs) play a central role in hypoxic adaptation. Especially, renal cell carcinoma (RCC) is often associated with von Hippel-Lindau (VHL) gene mutations, leading to up-regulation of HIFs. However, from a different point of view, this suggests the possibility that HIFs could be promising targets in anti-cancer therapy. In this study, we searched for HIF-1α-derived peptides that are able to induce RCC-reactive cytotoxic T lymphocytes (CTLs) from HLA-A24⁺ RCC patients. Among five peptides derived from HIF-1α, which were prepared based on the binding motif to the HLA-A24 allele, a HIF-1α_278-287 peptide induced peptide-specific CTLs from peripheral blood mononuclear cells of HLA-A24⁺ RCC patients most effectively. In immunoblot assays, the expression of HIF-1α was lowly detected in whole and nuclear lysates of RCC cell lines even under normoxia (20% O₂), and their expression in whole lysates was increased under hypoxia (1% O₂). Additionally, HIF-1α_278-287 peptide-stimulated T cells showed a higher cytotoxicity against HLA-A24⁺ HIF-1α-expressing RCC cells than against HLA-A24^- HIF-1α-expressing RCC cells. The cytotoxicity was inhibited by the addition of HIF-1α_278-287 peptide-pulsed cold target cells. Altogether, these results indicate that the HIF-1α_278-287 peptide could be a candidate for peptide-based anti-cancer vaccines for HLA-A24⁺ RCC patients.

Effective induction of cytotoxic T cells recognizing an epitope peptide derived from hypoxia-inducible protein 2 (HIG2) in patients with metastatic renal cell carcinoma

Purpose

Through genome-wide expression profile analysis, hypoxia-inducible protein 2 (HIG2) has previously been identified as an oncoprotein involved in development/progression of renal cell carcinoma (RCC). We subsequently identified a highly immunogenic HLA-A*0201/0206-restricted epitope peptide (HIG2-9-4) corresponding to a part of HIG2 and applied it as a therapeutic vaccine. We conducted a phase I clinical trial using the HIG2-9-4 peptide for patients with advanced RCC.

Materials and Methods

Nine patients having HLA-A*0201 or HLA-A*0206 with metastatic or unresectable RCC after failure of the cytokine and/or tyrosine kinase inhibitor therapies were enrolled in this study. The patients received subcutaneous administration of the peptide as an emulsion form with Montanide ISA-51 VG once a week in a dose-escalation manner (doses of 0.5, 1.0, or 3.0 mg/body, 3 patients for each dose). The primary endpoint was safety, and the secondary endpoints were immunological and clinical responses.

Results

Vaccinations with HIG2-9-4 peptide could be well tolerated without any serious systemic adverse events. Peptide-specific cytotoxic T lymphocyte (CTL) responses were detected in eight of the nine patients. Doses of 1.0 or 3.0 mg/body seemed to induce a CTL response better than did a dose of 0.5 mg/body, although the number of patients was too small to draw a firm conclusion. The disease control rate (stable disease for ≥4 months) was 77.8 %, and the median progression-free survival time was 10.3 months.

Conclusions

HIG2-9-4 peptide vaccine treatment was tolerable and effectively induced peptide-specific CTLs in RCC patients. This novel peptide vaccine therapy for RCC is promising.

A novel kinase mutation in VEGFR-1 predisposes its αC-helix/activation loop towards allosteric activation: Atomic insights from protein simulation

Vascular endothelial growth factor receptor 1 (VEGFR-1) has been implicated in diverse pathologies, including cancers. Although VEGFR-1 is considered as functionally impaired kinase, its decoy characteristics make it an important regulator of VEGFR-mediated signaling, particularly in tumor angiogenesis. VEGFR-1 conveys signaling via its tyrosine kinase (TK) domain whose activation is regulated by phosphorylation of specific tyrosine residues. Thus dysregulation of VEGFR-1 signaling, as reported in most of the cancers, might be a consequence of altered phosphorylation that could be attributed to genotypic variations in its TK domain. Considering the importance of TK domain of VEGFR-1, we carried out its mutational screening in 84 clinically validated and histopathologically confirmed colorectal cancer patients. By means of direct DNA sequencing and SNP analyses, eight novel variations, including one synonymous, two deletion, one missense and four intronic variations, were reported in the TK domain of VEGFR-1. rs730882263:C>G variation specifically reported in colon cancer, representing a single-atomic change (Sulfur to Oxygen) in the predicted (p.Cys1110Ser) protein, was observed as potentially deleterious variation as assessed by multiple single-nucleotide polymorphism prediction servers. Molecular dynamics simulations of VEGFR-1 Wt and (p.Cys1110Ser) variant models revealed major conformational changes in variant protein presumptuously generating an open conformation thereby exposing the activation domain and consequently increasing the probability of phosphorylation events: a condition frequently reported in cancers.

A Comparison Study of iTEP Nanoparticle-Based CTL Vaccine Carriers Revealed a Surprise Relationship between the Stability and Efficiency of the Carriers

Vaccine carriers have been shown to enhance cytotoxic T lymphocyte (CTL) epitope peptide vaccines by addressing intrinsic limitations of the vaccines. We have previously developed an immune-tolerant elastin-like polypeptide (iTEP)-based nanoparticle (NP) as an effective and unique CTL vaccine carrier. The NP is unique for its humoral immune tolerance, flexible structure, and ability to deliver CTL vaccines as polypeptide fusions. Here, we aimed to improve the NP by increasing its stability since we found it was not stable. We thus generated a more stable iTEP NP (ST-NP) and used it to deliver a CTL peptide vaccine, SIINFEKL. However, we surprisingly found that the ST-NP had a lower efficiency than the previously developed, marginally stable iTEP NP (MS-NP) in terms of promoting vaccine presentation and vaccine-induced CTL responses. On the other hand, dendritic cells (DCs) showed preferential uptake of the ST-NP but not the MS-NP. To develop an iTEP vaccine carrier that outperforms both the MS-NP and the ST-NP, we devised an iTEP NP that has a changeable stability responsive to a cytosolic, reductive environment, termed reductive environment-dependent NP or RED-NP. The RED-NP showed an intermediate ability to promote vaccine presentation and T cell responses in vitro between the MS-NP and the ST-NP. However, the RED-NP induced the strongest CTL responses in vivo among all three NPs. In conclusion, iTEP NPs that have a dynamically changeable stability are most effective to deliver and enhance CTL peptide vaccines. The work also demonstrated the versatile nature of iTEP vaccine carriers.

Autologous cytokine-induced killer (CIK) cell immunotherapy combined with cyclophosphamide in five patients with POEMS syndrome

The primary objective of this study was to evaluate the safety and clinical efficacy of autologous cytokine-induced killer (CIK) cells combined with cyclophosphamide in the treatment of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes (POEMS) syndrome patients. We evaluated five POEMS syndrome patients treated with autologous CIK cell immunotherapy combined with cyclophosphamide from 1 May 2012 to 30 November 2014. The Overall Neuropathy Limitation Scale (ONLS), computed tomography of the chest and abdomen, ultrasound of the abdomen, serum vascular endothelial growth factor (VEGF) level and lymphocyte count findings in the five patients were recorded. The median age of the patients was 40 years (range: 25-62), and all the patients were male. CIK cells were generated routinely from peripheral blood mononuclear cells (PBMCs) of all five patients, and the numbers of CIK cells increased by approximately 105-fold after 14 days of culture. All five patients (100%) responded to their neuropathy treatment, the ONLS scores were reduced by at least 1 and a paired-sample t-test revealed a significant difference (t = 5·715, P = 0·003 < 0·01). The extravascular volume overload responses indicated partial remission (PR = 60%) or stable disease (SD = 40%), and no cases of progressive disease (PD) or complete remission (CR) were observed. During clinical treatment, the serum VEGF of patient 5 decreased after one cycle of transfusion within 1 month. The lymphocyte counts of all the patients increased significantly after CIK transfusion, and a paired-sample t-test revealed a significant difference (t = 5·101, P = 0·004 < 0·01). Autologous CIK cell infusion combined with cyclophosphamide was found to be highly safe and elicited no adverse reactions. CIK cells can improve both the symptoms and quality of life, decrease serum VEGF levels and increase lymphocyte counts in patients with POEMS syndrome.

Peptide-Based Treatment: A Promising Cancer Therapy

Many new therapies are currently being used to treat cancer. Among these new methods, chemotherapy based on peptides has been of great interest due to the unique advantages of peptides, such as a low molecular weight, the ability to specifically target tumor cells, and low toxicity in normal tissues. In treating cancer, peptide-based chemotherapy can be mainly divided into three types, peptide-alone therapy, peptide vaccines, and peptide-conjugated nanomaterials. Peptide-alone therapy may specifically enhance the immune system's response to kill tumor cells. Peptide-based vaccines have been used in advanced cancers to improve patients' overall survival. Additionally, the combination of peptides with nanomaterials expands the therapeutic ability of peptides to treat cancer by enhancing drug delivery and sensitivity. In this review, we mainly focus on the new advances in the application of peptides in treating cancer in recent years, including diagnosis, treatment, and prognosis.

Present and future perspectives on immunotherapy for advanced renal cell carcinoma: Going to the core or beating around the bush?

Metastatic lesions of renal cell carcinoma (RCC) occasionally regress spontaneously after surgical removal of the primary tumor. Although this is an exceptionally rare occurrence, RCC has thus been postulated to be immunogenic. Immunotherapies, including cytokine therapy, peptide-based vaccines, and immune checkpoint inhibitors have therefore been used to treat patients with advanced, metastatic RCC. We review the history, trends, and recent progress in immunotherapy for advanced RCC and discuss future perspectives, with consideration of our experimental work on galectin 9 and PINCH as promising specific immunotherapy targets.

Vaccination approach to anti-angiogenic treatment of cancer

Improvement of patient survival by anti-angiogenic therapy has proven limited. A vaccination approach inducing an immune response against the tumor vasculature combines the benefits of immunotherapy and anti-angiogenesis, and may overcome the limitations of current anti-angiogenic drugs. Strategies to use whole endothelial cell vaccines and DNA- or protein vaccines against key players in the VEGF signaling axis, as well as specific markers of tumor endothelial cells, have been tested in preclinical studies. Current clinical trials are now testing the promise of this specific anti-cancer vaccination approach. This review will highlight the state-of-the-art in this exciting field of cancer research.

Analysis of adverse events following the treatment of autologous cytokine-induced killer cells for adoptive immunotherapy in malignant tumour sufferers

BACKGROUND

Adoptive immune cell transfer such as cytokine-induced killer (CIK) cells has become an important adjuvant approach in patients with tumours.

OBJECTIVES

The aim of this study was to analyse the adverse events (AEs) that occur during the transfusion of autologous CIK cells and to identify the risk factors associated with these AEs.

METHODS

Cell infusion-associated AEs were evaluated according to National Cancer Institute Common Terminology Criteria. Analysis was performed from a single-centre data on 893 malignant tumour patients who received a total of 4088 transfusions from March 2008 to October 2013.

RESULTS

A total of 215/4088 (5.26%) transfusion cases from 893 patients presented with AEs (Grade 1 - 4); 204/215 (94.88%) were Grade 1 - 2, and 156/215 (72.56%) occurred within 24 h. The most common AEs were fever (0.88%), chills (0.56%) and fatigue (0.49%). The rare but severe AEs included anaphylactoid purpura, tumour lysis syndrome, anaphylactic shock, arthralgia. No transfusion-associated death was noticed. The mainly relative risk factors for AEs included transfer cycles and clinical stages.

CONCLUSION

This study is a large-sample AEs research, to our knowledge, relative to immune cell transfusion from a single centre data analysis, revealing that autologous CIK cell therapy represents a fairly safe and well-tolerated treatment modality for malignant tumour patients, even rare severe, but not lethal AEs were observed in few patients.

MHC class I antigen presentation and implications for developing a new generation of therapeutic vaccines

Major histocompatibility complex class I (MHC-I) presented peptide epitopes provide a 'window' into the changes occurring in a cell. Conventionally, these peptides are generated by proteolysis of endogenously synthesized proteins in the cytosol, loaded onto MHC-I molecules, and presented on the cell surface for surveillance by CD8(+) T cells. MHC-I restricted processing and presentation alerts the immune system to any infectious or tumorigenic processes unfolding intracellularly and provides potential targets for a cytotoxic T cell response. Therefore, therapeutic vaccines based on MHC-I presented peptide epitopes could, theoretically, induce CD8(+) T cell responses that have tangible clinical impacts on tumor eradication and patient survival. Three major methods have been used to identify MHC-I restricted epitopes for inclusion in peptide-based vaccines for cancer: genetic, motif prediction and, more recently, immunoproteomic analysis. Although the first two methods are capable of identifying T cell stimulatory epitopes, these have significant disadvantages and may not accurately represent epitopes presented by a tumor cell. In contrast, immunoproteomic methods can overcome these disadvantages and identify naturally processed and presented tumor associated epitopes that induce more clinically relevant tumor specific cytotoxic T cell responses. In this review, we discuss the importance of using the naturally presented MHC-I peptide repertoire in formulating peptide vaccines, the recent application of peptide-based vaccines in a variety of cancers, and highlight the pros and cons of the current state of peptide vaccines.

Identification of erythropoietin receptor-derived peptides having the potential to induce cancer-reactive cytotoxic T lymphocytes from HLA-A24(+) patients with renal cell carcinoma

Molecular targeting therapy with anti-angiogenic agents, including sunitinib and sorafenib, has been proven to be the first- and second-line standard treatments for metastatic renal cell carcinoma (mRCC) worldwide. Despite their significant antitumor effects, most of the patients with mRCC have not been cured. Under such circumstances, anti-cancer immunotherapy has been considered as a promising treatment modality for mRCC, and cytotoxic T lymphocytes (CTLs) are the most powerful effectors among several immune cells and molecules. Therefore, we previously conducted anti-cancer vaccine therapy with peptides derived from carbonic anhydrase-9 and vascular endothelial growth factor receptor-1 as phase-I/II trials for mRCC patients and reported their clinical benefits. Alternatively, up-regulated expression of erythropoietin (Epo) and its receptor (EpoR) in RCC has been reported, and their co-expression is involved in tumorigenesis. In order to increase options for peptide-based vaccination therapy, we searched for novel EpoR-peptides for HLA-A24(+) RCC patients. Among 5 peptides derived from EpoR, which were prepared based on the binding motif to the HLA-A24 allele, EpoR52-60 peptide had the potential to induce peptide-specific CTLs from peripheral blood mononuclear cells of HLA-A24(+) RCC patients. Cytotoxicity toward HLA-A24(+) and EpoR-expressing RCC cells was ascribed to peptide-specific CD8(+) T cells. These results indicate that the EpoR52-60 peptide could be a promising candidate for a peptide-based anti-cancer vaccine for HLA-A24(+) mRCC patients.

Specific active immunotherapy with a VEGF vaccine in patients with advanced solid tumors. results of the CENTAURO antigen dose escalation phase I clinical trial

CIGB-247 is a novel cancer therapeutic vaccine that uses a human VEGF variant molecule as antigen, in combination with a bacterial adjuvant. In mice, CIGB-247 has anti-tumor and anti-metastatic effects. The vaccine induces anti-VEGF blocking antibodies and a cellular response targeting tumor cells producing VEGF, and has proven to be safe in mice, rats, rabbits and non-human primates. Herein we report the results of a Phase I clinical trial (code name CENTAURO) where safety, tolerance, and immunogenicity of CIGB-247 were studied in 30 patients with advanced solid tumors, at three antigen dose levels. Individuals were subcutaneously immunized for 8 consecutive weeks with 50, 100 or 400 μg of antigen, and re-immunized on week twelve. On week sixteen, evaluations of safety, tolerance, clinical status, and immunogenicity (seroconversion for anti-VEGF IgG, serum VEGF/KDR-Fc blocking ability, and gamma-IFN ELISPOT with blood cells stimulated in vitro with mutated VEGF) were done. Surviving patients were eligible for off-trial additional 4-week re-immunizations with 400 μg of antigen. Immunogenicity and clinical status were again studied on weeks 25 and 49. Vaccination was shown to be safe at the three dose levels, with only grade 1-2 adverse events. CIGB-247 was immunogenic and higher numbers of individuals positive to the three immune response tests were seen with increasing antigen dose. Off-protocol long-term vaccination produced no additional adverse events or negative changes in immunogenicity. Eleven patients are still alive, with overall survivals ranging from 20 to 24 months. Twelve of the thirty patients exhibited objective clinical benefits, and two individuals have complete responses. Most patients with higher survivals are positive in the three immune response tests. In summary, this is the first clinical testing report of a cancer therapeutic vaccine based on a human VEGF related molecule as antigen. The CIGB-247 vaccine is safe, immunogenic, and merits further clinical development.

REGISTRATION NUMBER AND NAME OF TRIAL REGISTRY

RPCEC00000102. Cuban Public Clinical Trial Registry (WHO accepted Primary Registry). Available from: http://registroclinico.sld.cu/.

Autologous CIK cell immunotherapy in patients with renal cell carcinoma after radical nephrectomy

Objective. To evaluate the efficacy of autologous cytokine-induced killer (CIK) cells in patients with renal cell carcinoma (RCC). Methods. 20 patients diagnosed with TNM stage I or II RCC were randomly divided into two groups, a CIK cell treatment group and a control group. The endpoint was progression-free survival (PFS) evaluated by Kaplan-Meier analyses. Results. CD3⁺, CD3⁺/CD8⁺, CD3⁺/CD4⁺, and CD3⁺/CD56⁺ levels increased after CIK cell culture (P < 0.01). The median PFS in CIK cell treatment group was significantly longer than that in control group (PFS, 32.2 months versus 21.6 months; log-rank, P = 0.032), all patients were alive during the course of followup, and there are no statistically significant differences between two groups in OS (log-rank, P = 0.214). Grade III or greater adverse events were not observed. Conclusions. CIK cells treatment could prolong survival in patients with RCC after radical nephrectomy and showed acceptable curative effect with potential enhancement of cellular immune function. This trial is registered with Clinicaltrials.gov NCT01799083.

Recent progress in peptide vaccination in cancer with a focus on non-small-cell lung cancer

Active immunotherapy aimed at the stimulation of tumor-specific T cells has established itself within the clinic as a therapeutic option to treat cancer. One strategy is the use of so-called peptides that mimic genuine T-cell epitopes as vaccines to activate tumor-specific T cells. In various clinical trials, different types of vaccines, adjuvants and other immunomodulatory compounds were evaluated in patients with different types of tumors. Here, we review the trials published in the last 3 years focusing on the T-cell response, the effect of immunomodulation and potential relationships with clinical outcomes. Furthermore, we would like to make a case for the development of peptide vaccines aiming to treat non-small-cell lung cancer, the most common cause of cancer mortality.

Trial Watch: Peptide vaccines in cancer therapy

Throughout the past 3 decades, along with the recognition that the immune system not only influences oncogenesis and tumor progression, but also determines how established neoplastic lesions respond therapy, renovated enthusiasm has gathered around the possibility of using vaccines as anticancer agents. Such an enthusiasm quickly tempered when it became clear that anticancer vaccines would have to be devised as therapeutic, rather than prophylactic, measures, and that malignant cells often fail to elicit (or actively suppress) innate and adaptive immune responses. Nonetheless, accumulating evidence indicates that a variety of anticancer vaccines, including cell-based, DNA-based, and purified component-based preparations, are capable of circumventing the poorly immunogenic and highly immunosuppressive nature of most tumors and elicit (at least under some circumstances) therapeutically relevant immune responses. Great efforts are currently being devoted to the identification of strategies that may provide anticancer vaccines with the capacity of breaking immunological tolerance and eliciting tumor-associated antigen-specific immunity in a majority of patients. In this sense, promising results have been obtained by combining anticancer vaccines with a relatively varied panels of adjuvants, including multiple immunostimulatory cytokines, Toll-like receptor agonists as well as inhibitors of immune checkpoints. One year ago, in the December issue of OncoImmunology, we discussed the biological mechanisms that underlie the antineoplastic effects of peptide-based vaccines and presented an abundant literature demonstrating the prominent clinical potential of such an approach. Here, we review the latest developments in this exciting area of research, focusing on high-profile studies that have been published during the last 13 mo and clinical trials launched in the same period to evaluate purified peptides or full-length proteins as therapeutic anticancer agents.