Nanoparticle-based antigen carrier systems have become a significant area of research with the advancement of nanotechnology. Biodegradable polymers have emerged as particularly promising carrier vehicles due to their ability to address the limitations of existing vaccine systems. In this study, we successfully encapsulated the G5-24 linear peptide, located between amino acids 253 and 275 in the primary sequence of the rabies virus G protein, into biodegradable and biocompatible PLGA copolymer using the double emulsion solvent evaporation method. The resulting nanoparticles had a size of approximately 230.9 ± 0.9074 nm, with a PDI value of 0.168 ± 0.017 and a zeta potential value of -9.86 ± 0.132 mV. SEM images confirmed that the synthesized nanoparticles were uniform in size and distribution. Additionally, FTIR spectra indicated successful peptide loading into the nanoparticles. The encapsulation efficiency of the peptide-loaded nanoparticles was 73.3%, with a peptide loading capacity of 48.2% and a reaction yield of 30.4%. Peptide release studies demonstrated that 65.55% of the peptide was released in a controlled manner over 28 d, following a 'biphasic burst release' profile consistent with the degradation profile of PLGA. This controlled release is particularly beneficial for vaccine studies. Cytotoxicity tests revealed that the R-NP formulation did not induce cytotoxicity in fibroblast cells and enhanced NO production in macrophages, indicating its potential for vaccine development.

Fibroblast activation protein (FAPα) is a tumor stromal antigen expressed by cancer-associated fibroblasts (CAFs) in more than 90 % of malignant epithelial carcinomas. FAPα-based immunotherapy has been reported and showed that FAPα-specific immune response can remold immune microenvironment and contribute to tumor regression. Many FAPα-based vaccines have been investigated in preclinical trials, which can elicit strong and durable cytolytic T lymphocytes (CTL) with good safety. However, epitope-based FAPα vaccines are rarely reported. To break tolerance against self-antigens, analogue epitopes with modified peptides at the anchor residues are typically used to improve epitope immunogenicity. To investigate the feasibility of a FAPα epitope-based vaccine for cancer immunotherapy in vivo, we conducted a preclinical study to identify a homologous CTL epitope of human and mouse FAPα and obtained its analogue epitope in BALB/c mice, and explored the anti-tumor activity of their minigene vaccines in 4 T1 tumor-bearing mice. By using in silico epitope prediction tools and immunogenicity assays, immunodominant epitope FAP.291 (YYFSWLTWV) and its analogue epitope FAP.291I9 (YYFSWLTWI) were identified. The FAP.291-based epitope minigene vaccine successfully stimulated CTLs targeting CAFs and exhibited anti-tumor activity in a 4 T1 murine breast cancer model. Furthermore, although the analogue epitope FAP.291I9 enhanced FAP.291-specific immune responses, improvement of anti-tumor immunity effects was not observed. Check of immunosuppressive factors revealed that the high levels of IL-10, IL-13, myeloid-derived suppressor cells and iNOS induced by FAP.291I9 increased, which considered the main cause of the failure of the analogue epitope-based vaccine. Thus, we demonstrated for the first time that the FAP.291 minigene vaccine could induce mouse CTLs and also function as a tumor regression antigen, providing the basis for future studies of FAPα epitope-based vaccines. This study may also be valuable for further improvement of the immunogenicity of analogue epitope vaccines.

Vaccines are designed to leverage the immune system and produce long-lasting protection against specific diseases. Peptide vaccines are regarded as safe and effective way of circumventing problems such as mild allergic reactions associated with conventional vaccines. The biggest challenges associated with formulation of peptide vaccines are stability issues and conformational changes which lead to destruction of their activity when exposed to lyophilization process that may act as stressors. Lyophilization process is aimed at removal of water which involves freezing, primary drying and secondary drying. To safeguard the peptide molecules from such stresses, cryoprotectants are used to offer them viability and structural stability. This paper is an attempt to understand the physicochemical properties of peptide vaccines, mechanism of cryoprotection under the shed of water replacement, water substitution theory and cation-pi interaction theory of amino acids which aims at shielding the peptide from external environment by formation of hydrogen bonds, covalent bonds or cation-pi interaction between cryoprotectant and peptide followed by selection criteria of cryoprotectants and their utility in peptide vaccines development along with challenges and opportunities.

Genetic variability across the three major histocompatibility complex (MHC) class I genes (human leukocyte antigen [HLA] A, B, and C) may affect susceptibility to many diseases such as cancer, auto-immune or infectious diseases. Individual genetic variation may help to explain different immune responses to microorganisms across a population. HLA typing can be fast and inexpensive; however, deciphering peptides loaded on MHC-I and II which are presented to T cells, require the design and development of high-sensitivity methodological approaches and subsequently databases. Hence, these novel strategies and databases could help in the generation of vaccines using these potential immunogenic peptides and in identifying high-risk HLA types to be prioritized for vaccination programs. Herein, the recent developments and approaches, in this field, focusing on the identification of immunogenic peptides have been reviewed and the next steps to promote their translation into biomedical and clinical practice are discussed.

The COVID-19 pandemic has affected 215 countries and territories around the world with 60,187,347 coronavirus cases and 17,125,719 currently infected patients confirmed as of the November 25, 2020. Currently, many countries are working on developing new vaccines and therapeutic drugs for this novel virus strain, and a few of them are in different phases of clinical trials. The advancement in high-throughput sequence technologies, along with the application of bioinformatics, offers invaluable knowledge on genomic characterization and molecular pathogenesis of coronaviruses. Recent multi-disciplinary studies using bioinformatics methods like sequence-similarity, phylogenomic, and computational structural biology have provided an in-depth understanding of the molecular and biochemical basis of infection, atomic-level recognition of the viral-host receptor interaction, functional annotation of important viral proteins, and evolutionary divergence across different strains. Additionally, various modern immunoinformatic approaches are also being used to target the most promiscuous antigenic epitopes from the SARS-CoV-2 proteome for accelerating the vaccine development process. In this review, we summarize various important computational tools and databases available for systematic sequence-structural study on coronaviruses. The features of these public resources have been comprehensively discussed, which may help experimental biologists with predictive insights useful for ongoing research efforts to find therapeutics against the infectious COVID-19 disease.

The broad relationship between the immune system and cancer is opening a new hallmark to explore for nanomedicine. Here, all the common and synergy points between both areas are reviewed and described, and the recent approaches which show the progress from the bench to the beside to biomarkers developed in nanomedicine and onco-immunotherapy.

Cancer is a worldwide medical problem with significant repercussions on individual patients and societies as a whole. In order to alter the outcomes of this deadly disease the treatment of cancer over the centuries has undergone a unique evolution. However, utilizing the best treatment modalities and achieving cures or long-term durable responses have been inconsistent and limited, that is until recently. Contemporary research has highlighted a fundamental gap in our understanding of how we approach treating cancer, by revealing the intricate relationship between the immune system and tumors. In this atmosphere, the growth of immunotherapy has not only forever changed our understanding of cancer biology, but the manner by which we treat patients. It's paradigm shifting success has led to the approval of over 10 different immunotherapeutic agents, including checkpoint inhibitors, vaccine-based therapies, oncolytic viruses and T cell directed therapies for nearly 20 different indications across countless tumor types. Despite the breakthroughs that have occurred in the field of immunotherapy, it has not been the panacea for all cancers. With a deeper understanding of the immune system we have been able to peer into tumor immune escape and therapy resistance. Simultaneously this understanding has paved the way for the investigation and development of novel immune system altering agents and combinatorial therapies. In this chapter we review the immune system and its intricate relationship with cancer, the evolution of immunotherapy, its current landscape, and future directions in the context of resistance mechanisms and the challenges faced by immunotherapy against cancer.

The prognosis of people with metastatic cutaneous melanoma, a skin cancer, is generally poor. Recently, new classes of drugs (e.g. immune checkpoint inhibitors and small-molecule targeted drugs) have significantly improved patient prognosis, which has drastically changed the landscape of melanoma therapeutic management. This is an update of a Cochrane Review published in 2000.

To assess the beneficial and harmful effects of systemic treatments for metastatic cutaneous melanoma.

We searched the following databases up to October 2017: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase and LILACS. We also searched five trials registers and the ASCO database in February 2017, and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs).

We considered RCTs of systemic therapies for people with unresectable lymph node metastasis and distant metastatic cutaneous melanoma compared to any other treatment. We checked the reference lists of selected articles to identify further references to relevant trials.

Two review authors extracted data, and a third review author independently verified extracted data. We implemented a network meta-analysis approach to make indirect comparisons and rank treatments according to their effectiveness (as measured by the impact on survival) and harm (as measured by occurrence of high-grade toxicity). The same two review authors independently assessed the risk of bias of eligible studies according to Cochrane standards and assessed evidence quality based on the GRADE criteria.

We included 122 RCTs (28,561 participants). Of these, 83 RCTs, encompassing 21 different comparisons, were included in meta-analyses. Included participants were men and women with a mean age of 57.5 years who were recruited from hospital settings. Twenty-nine studies included people whose cancer had spread to their brains. Interventions were categorised into five groups: conventional chemotherapy (including single agent and polychemotherapy), biochemotherapy (combining chemotherapy with cytokines such as interleukin-2 and interferon-alpha), immune checkpoint inhibitors (such as anti-CTLA4 and anti-PD1 monoclonal antibodies), small-molecule targeted drugs used for melanomas with specific gene changes (such as BRAF inhibitors and MEK inhibitors), and other agents (such as anti-angiogenic drugs). Most interventions were compared with chemotherapy. In many cases, trials were sponsored by pharmaceutical companies producing the tested drug: this was especially true for new classes of drugs, such as immune checkpoint inhibitors and small-molecule targeted drugs.When compared to single agent chemotherapy, the combination of multiple chemotherapeutic agents (polychemotherapy) did not translate into significantly better survival (overall survival: HR 0.99, 95% CI 0.85 to 1.16, 6 studies, 594 participants; high-quality evidence; progression-free survival: HR 1.07, 95% CI 0.91 to 1.25, 5 studies, 398 participants; high-quality evidence. Those who received combined treatment are probably burdened by higher toxicity rates (RR 1.97, 95% CI 1.44 to 2.71, 3 studies, 390 participants; moderate-quality evidence). (We defined toxicity as the occurrence of grade 3 (G3) or higher adverse events according to the World Health Organization scale.)Compared to chemotherapy, biochemotherapy (chemotherapy combined with both interferon-alpha and interleukin-2) improved progression-free survival (HR 0.90, 95% CI 0.83 to 0.99, 6 studies, 964 participants; high-quality evidence), but did not significantly improve overall survival (HR 0.94, 95% CI 0.84 to 1.06, 7 studies, 1317 participants; high-quality evidence). Biochemotherapy had higher toxicity rates (RR 1.35, 95% CI 1.14 to 1.61, 2 studies, 631 participants; high-quality evidence).With regard to immune checkpoint inhibitors, anti-CTLA4 monoclonal antibodies plus chemotherapy probably increased the chance of progression-free survival compared to chemotherapy alone (HR 0.76, 95% CI 0.63 to 0.92, 1 study, 502 participants; moderate-quality evidence), but may not significantly improve overall survival (HR 0.81, 95% CI 0.65 to 1.01, 2 studies, 1157 participants; low-quality evidence). Compared to chemotherapy alone, anti-CTLA4 monoclonal antibodies is likely to be associated with higher toxicity rates (RR 1.69, 95% CI 1.19 to 2.42, 2 studies, 1142 participants; moderate-quality evidence).Compared to chemotherapy, anti-PD1 monoclonal antibodies (immune checkpoint inhibitors) improved overall survival (HR 0.42, 95% CI 0.37 to 0.48, 1 study, 418 participants; high-quality evidence) and probably improved progression-free survival (HR 0.49, 95% CI 0.39 to 0.61, 2 studies, 957 participants; moderate-quality evidence). Anti-PD1 monoclonal antibodies may also result in less toxicity than chemotherapy (RR 0.55, 95% CI 0.31 to 0.97, 3 studies, 1360 participants; low-quality evidence).Anti-PD1 monoclonal antibodies performed better than anti-CTLA4 monoclonal antibodies in terms of overall survival (HR 0.63, 95% CI 0.60 to 0.66, 1 study, 764 participants; high-quality evidence) and progression-free survival (HR 0.54, 95% CI 0.50 to 0.60, 2 studies, 1465 participants; high-quality evidence). Anti-PD1 monoclonal antibodies may result in better toxicity outcomes than anti-CTLA4 monoclonal antibodies (RR 0.70, 95% CI 0.54 to 0.91, 2 studies, 1465 participants; low-quality evidence).Compared to anti-CTLA4 monoclonal antibodies alone, the combination of anti-CTLA4 plus anti-PD1 monoclonal antibodies was associated with better progression-free survival (HR 0.40, 95% CI 0.35 to 0.46, 2 studies, 738 participants; high-quality evidence). There may be no significant difference in toxicity outcomes (RR 1.57, 95% CI 0.85 to 2.92, 2 studies, 764 participants; low-quality evidence) (no data for overall survival were available).The class of small-molecule targeted drugs, BRAF inhibitors (which are active exclusively against BRAF-mutated melanoma), performed better than chemotherapy in terms of overall survival (HR 0.40, 95% CI 0.28 to 0.57, 2 studies, 925 participants; high-quality evidence) and progression-free survival (HR 0.27, 95% CI 0.21 to 0.34, 2 studies, 925 participants; high-quality evidence), and there may be no significant difference in toxicity (RR 1.27, 95% CI 0.48 to 3.33, 2 studies, 408 participants; low-quality evidence).Compared to chemotherapy, MEK inhibitors (which are active exclusively against BRAF-mutated melanoma) may not significantly improve overall survival (HR 0.85, 95% CI 0.58 to 1.25, 3 studies, 496 participants; low-quality evidence), but they probably lead to better progression-free survival (HR 0.58, 95% CI 0.42 to 0.80, 3 studies, 496 participants; moderate-quality evidence). However, MEK inhibitors probably have higher toxicity rates (RR 1.61, 95% CI 1.08 to 2.41, 1 study, 91 participants; moderate-quality evidence).Compared to BRAF inhibitors, the combination of BRAF plus MEK inhibitors was associated with better overall survival (HR 0.70, 95% CI 0.59 to 0.82, 4 studies, 1784 participants; high-quality evidence). BRAF plus MEK inhibitors was also probably better in terms of progression-free survival (HR 0.56, 95% CI 0.44 to 0.71, 4 studies, 1784 participants; moderate-quality evidence), and there appears likely to be no significant difference in toxicity (RR 1.01, 95% CI 0.85 to 1.20, 4 studies, 1774 participants; moderate-quality evidence).Compared to chemotherapy, the combination of chemotherapy plus anti-angiogenic drugs was probably associated with better overall survival (HR 0.60, 95% CI 0.45 to 0.81; moderate-quality evidence) and progression-free survival (HR 0.69, 95% CI 0.52 to 0.92; moderate-quality evidence). There may be no difference in terms of toxicity (RR 0.68, 95% CI 0.09 to 5.32; low-quality evidence). All results for this comparison were based on 324 participants from 2 studies.Network meta-analysis focused on chemotherapy as the common comparator and currently approved treatments for which high- to moderate-quality evidence of efficacy (as represented by treatment effect on progression-free survival) was available (based on the above results) for: biochemotherapy (with both interferon-alpha and interleukin-2); anti-CTLA4 monoclonal antibodies; anti-PD1 monoclonal antibodies; anti-CTLA4 plus anti-PD1 monoclonal antibodies; BRAF inhibitors; MEK inhibitors, and BRAF plus MEK inhibitors. Analysis (which included 19 RCTs and 7632 participants) generated 21 indirect comparisons.The best evidence (moderate-quality evidence) for progression-free survival was found for the following indirect comparisons:• both combinations of immune checkpoint inhibitors (HR 0.30, 95% CI 0.17 to 0.51) and small-molecule targeted drugs (HR 0.17, 95% CI 0.11 to 0.26) probably improved progression-free survival compared to chemotherapy;• both BRAF inhibitors (HR 0.40, 95% CI 0.23 to 0.68) and combinations of small-molecule targeted drugs (HR 0.22, 95% CI 0.12 to 0.39) were probably associated with better progression-free survival compared to anti-CTLA4 monoclonal antibodies;• biochemotherapy (HR 2.81, 95% CI 1.76 to 4.51) probably lead to worse progression-free survival compared to BRAF inhibitors;• the combination of small-molecule targeted drugs probably improved progression-free survival (HR 0.38, 95% CI 0.21 to 0.68) compared to anti-PD1 monoclonal antibodies;• both biochemotherapy (HR 5.05, 95% CI 3.01 to 8.45) and MEK inhibitors (HR 3.16, 95% CI 1.77 to 5.65) were probably associated with worse progression-free survival compared to the combination of small-molecule targeted drugs; and• biochemotherapy was probably associated with worse progression-free survival (HR 2.81, 95% CI 1.54 to 5.11) compared to the combination of immune checkpoint inhibitors.The best evidence (moderate-quality evidence) for toxicity was found for the following indirect comparisons:• combination of immune checkpoint inhibitors (RR 3.49, 95% CI 2.12 to 5.77) probably increased toxicity compared to chemotherapy;• combination of immune checkpoint inhibitors probably increased toxicity (RR 2.50, 95% CI 1.20 to 5.20) compared to BRAF inhibitors;• the combination of immune checkpoint inhibitors probably increased toxicity (RR 3.83, 95% CI 2.59 to 5.68) compared to anti-PD1 monoclonal antibodies; and• biochemotherapy was probably associated with lower toxicity (RR 0.41, 95% CI 0.24 to 0.71) compared to the combination of immune checkpoint inhibitors.Network meta-analysis-based ranking suggested that the combination of BRAF plus MEK inhibitors is the most effective strategy in terms of progression-free survival, whereas anti-PD1 monoclonal antibodies are associated with the lowest toxicity.Overall, the risk of bias of the included trials can be considered as limited. When considering the 122 trials included in this review and the seven types of bias we assessed, we performed 854 evaluations only seven of which (< 1%) assigned high risk to six trials.

We found high-quality evidence that many treatments offer better efficacy than chemotherapy, especially recently implemented treatments, such as small-molecule targeted drugs, which are used to treat melanoma with specific gene mutations. Compared with chemotherapy, biochemotherapy (in this case, chemotherapy combined with both interferon-alpha and interleukin-2) and BRAF inhibitors improved progression-free survival; BRAF inhibitors (for BRAF-mutated melanoma) and anti-PD1 monoclonal antibodies improved overall survival. However, there was no difference between polychemotherapy and monochemotherapy in terms of achieving progression-free survival and overall survival. Biochemotherapy did not significantly improve overall survival and has higher toxicity rates compared with chemotherapy.There was some evidence that combined treatments worked better than single treatments: anti-PD1 monoclonal antibodies, alone or with anti-CTLA4, improved progression-free survival compared with anti-CTLA4 monoclonal antibodies alone. Anti-PD1 monoclonal antibodies performed better than anti-CTLA4 monoclonal antibodies in terms of overall survival, and a combination of BRAF plus MEK inhibitors was associated with better overall survival for BRAF-mutated melanoma, compared to BRAF inhibitors alone.The combination of BRAF plus MEK inhibitors (which can only be administered to people with BRAF-mutated melanoma) appeared to be the most effective treatment (based on results for progression-free survival), whereas anti-PD1 monoclonal antibodies appeared to be the least toxic, and most acceptable, treatment.Evidence quality was reduced due to imprecision, between-study heterogeneity, and substandard reporting of trials. Future research should ensure that those diminishing influences are addressed. Clinical areas of future investigation should include the longer-term effect of new therapeutic agents (i.e. immune checkpoint inhibitors and targeted therapies) on overall survival, as well as the combination of drugs used in melanoma treatment; research should also investigate the potential influence of biomarkers.

Thymidylate synthase (TS) is a tumor-associated enzyme critical for DNA replication and main 5'-fluorouracil (5'-FU) target. TSPP/VAC1 is a multi-arm trial phase-Ib trial program aimed to investigate the toxicity and biomodulatory activity of a poly-epitope-peptide vaccine to TS (TSPP) in cancer patients (pts). Here, we present the results of the TSPP/VAC1/arm C trial aimed to evaluate TSPP in combination with chemo-immunotherapy in pretreated metastatic colo-rectal cancer (mCRC) pts. Twenty-nine pts, 14 males and 15 females, received poly-chemotherapy with gemcitabine [GEM; 1,000 mg/sqm, day-1], oxaliplatin [OX; 80 mg/sqm, day-2], levofolinate [100 mg/sqm, days 1-2], bolus/infusional 5'-FU [400 mg/800 mg/sqm, days 1-2], sargramostim [50 μg, days 3-7/q30], and interleukin-2 [sc. 0.5 MIU twice a day, days 8-14/18-30] [GOLFIG-regimen]. Seventeen pts received sc. TSPP injections at escalating dosage [3 pts, 100 µg (DL-1); 3 pts, 200 µg (DL-2) and 11pts, 300 µg (DL-3)] one week after each chemotherapy cycle (concomitant module), while 10 out 12 pts received TSPP (300 µg) after 12 GOLFIG courses [dose level (DL)-0] (sequential module). TSPP MTD was not achieved. Adverse events consisted in swelling/erythema at injection sites (17 cases), G1-2 haematological (16 cases) and gastro-enteric events (12), fever, rhinitis, conjunctivitis, and poly-arthralgia and rise in auto-antibodies [ANA, ENA, c-ANCA, p-ANCA in the DL1-3 pts]. Both treatment-modules showed immunomodulating and antitumor activity (disease-control-rate, DL1-3 and DL0 were 70.6% and 83.3%, respectively) with a better survival recorded in the second group [median OS DL1-3 vs. DL0 = 8 vs. 16 mo, p = 0.049]. The promising long-term survival produced by the sequential treatment module deserves further phase II evaluation.

Thymidylate synthase (TS) poly-epitope peptide (TSPP) is a 27-mer peptide vaccine containing the amino acidic sequences of three epitopes with HLA-A2.1-binding motifs of TS, an enzyme overexpressed in cancer cells, which plays a crucial role in DNA repair and replication. Based on the results of preclinical studies, we designed a phase Ib trial (TSPP/VAC1) to investigate, in a dose escalation setting, the safety and the biological activity of TSPP vaccination alone (arm A) or in combination with GM-CSF and IL-2 (arm B) in cancer patients. Twenty-one pretreated metastatic cancer patients, with a good performance status (ECOG ≤ 1) and no severe organ failure or immunological disease, were enrolled in the study (12 in arm A, nine in arm B) between April 2011 and January 2012, with a median follow-up of 28 months. TSPP resulted safe, and its maximal tolerated dose was not achieved. No grade 4 toxicity was observed. The most common adverse events were grade 2 dermatological reactions to the vaccine injection, cough, rhinitis, fever, poly-arthralgia, gastro-enteric symptoms and, to a lesser extent, moderate hypertension and hypothyroidism. We detected a significant rise in auto-antibodies and TS-epitope-specific CTL precursors. Furthermore, TSPP showed antitumor activity in this group of pretreated patients; indeed, we recorded one partial response and seven disease stabilizations (SD) in arm A, and three SD in arm B. Taken together, our findings provide the framework for the evaluation of the TSPP anti-tumor activity in further disease-oriented clinical trials.

Vaccines are designed to educate the host immune system to prevent infectious disease or to fight against various diseases such as cancers. Peptides were first employed to provide specific immune responses while minimizing unintended allergenic or reactogenic adverse effects. Discoveries of virus or cancer-specific antigens and the advanced knowledge of immunology accelerate the peptide vaccine development. Despite the overwhelming research pipelines, a very few of them reached to market approvals or phase III clinical trials, because of the lack of efficacy. Several strategies for the next generation peptide vaccines are devised to overcome the weak immunogenicity and the poor delivery. In this review, we discuss the new promising strategies of peptide vaccine development which are recently developed in preclinical and/or clinical stage focusing the roles of peptides in the vaccine formulation from epitope to adjuvant. Additionally, we discuss the future perspectives of peptide vaccine and immunotherapy.

The fact that cancer immunotherapy is considered to be a safe and successful weapon for use in combination with surgery, radiation, and chemotherapy treatments means that it has recently been chosen as Breakthrough of the Year 2013 by Science editors. Anticancer vaccines have been extensively tested, in this field, both in preclinical cancer models and in the clinic. However, tumor-associated antigens (TAAs) are often self-tolerated molecules and cancer patients suffer from strong immunosuppressive effects, meaning that the triggering of an effective anti-tumor immune response is difficult. One possible means to overcome immunological tolerance to self-TAAs is of course the use of vaccines that code for xenogeneic proteins. However, a low-affinity antibody response against the self-homologous protein expressed by cancer cells is generally induced by xenovaccination. This issue becomes extremely limiting when working with tumors in which the contribution of the humoral rather than the cellular immune response is required if tumor growth is to be hampered. A possible way to avoid this problem is to use hybrid vaccines which code for chimeric proteins that include both homologous and xenogeneic moieties. In fact, a superior protective anti-tumor immune response against ErbB2⁺ transplantable and autochthonous mammary tumors was observed over plasmids that coded for the fully rat or fully human proteins when hybrid plasmids that coded for chimeric rat/human ErbB2 protein were tested in ErbB2 transgenic mice. In principle, these findings may become the basis for a new rational means of designing effective vaccines against TAAs.

Pancreatic cancer (PC) is the 5th leading cause of cancer related death in the developed world with more than 260,000 deaths annually worldwide and with a dismal 5-year survival. Surgery is the only potential hope of cure for PC, but, unfortunately, only 20% PC patients is resectable at the time of diagnosis. Therapeutic research efforts have mainly focused on improvements in radio/ chemo treatments and to date, there are only a few chemotherapeutic agents that have shown to be effective against PC, including gemcitabine with or without abraxane as well as a combination of 5-FU, leucovorin, oxaliplatin and irinotecan (the so-called FOLFIRINOX regimen). The survival of patients treated with these regimens is marginal and hence we are in urgent need of novel therapeutic approaches to treat pancreatic cancer. The success of immunotherapeutic strategies in other cancers and various evidences that pancreatic adenocarcinoma elicits antitumor immune responses, suggest that immunotherapies can be a promising alternative treatment modality for this deadly disease. PC immunotherapy treatments include passive immunotherapeutic approaches, such as the use of effector cells generated in vitro, and active immunotherapeutic strategies, which goal is to stimulate an antitumor response in vivo, by means of vaccination. In this review, we describe the immune suppressive mechanisms of pancreatic cancer and discuss recent preclinical and clinical efforts toward PC immunotherapy, including passive approaches, such as the use of antibodies and active strategies (vaccination), with a special mention of most recent treatment with CRS-207 and GVAX.

Dendritic cells (DCs) occupy a privileged position at the interface between innate and adaptive immunity, orchestrating a large panel of responses to both physiological and pathological cues. In particular, whereas the presentation of antigens by immature DCs generally results in the development of immunological tolerance, mature DCs are capable of priming robust, and hence therapeutically relevant, adaptive immune responses. In line with this notion, functional defects in the DC compartment have been shown to etiologically contribute to pathological conditions including (but perhaps not limited to) infectious diseases, allergic and autoimmune disorders, graft rejection and cancer. Thus, the possibility of harnessing the elevated immunological potential of DCs for anticancer therapy has attracted considerable interest from both researchers and clinicians over the last decade. Alongside, several methods have been developed not only to isolate DCs from cancer patients, expand them, load them with tumor-associated antigens and hence generate highly immunogenic clinical grade infusion products, but also to directly target DCs in vivo. This intense experimental effort has culminated in 2010 with the approval by the US FDA of a DC-based preparation (sipuleucel-T, Provenge®) for the treatment of asymptomatic or minimally symptomatic metastatic castration-refractory prostate cancer. As an update to the latest Trial Watch dealing with this exciting field of research (October 2012), here we summarize recent advances in DC-based anticancer regimens, covering both high-impact studies that have been published during the last 13 mo and clinical trials that have been launched in the same period to assess the antineoplastic potential of this variant of cellular immunotherapy.

Predicting the binding mode of flexible polypeptides to proteins is an important task that falls outside the domain of applicability of most small molecule and protein-protein docking tools. Here, we test the small molecule flexible ligand docking program Glide on a set of 19 non-α-helical peptides and systematically improve pose prediction accuracy by enhancing Glide sampling for flexible polypeptides. In addition, scoring of the poses was improved by post-processing with physics-based implicit solvent MM-GBSA calculations. Using the best RMSD among the top 10 scoring poses as a metric, the success rate (RMSD ≤ 2.0 Å for the interface backbone atoms) increased from 21% with default Glide SP settings to 58% with the enhanced peptide sampling and scoring protocol in the case of redocking to the native protein structure. This approaches the accuracy of the recently developed Rosetta FlexPepDock method (63% success for these 19 peptides) while being over 100 times faster. Cross-docking was performed for a subset of cases where an unbound receptor structure was available, and in that case, 40% of peptides were docked successfully. We analyze the results and find that the optimized polypeptide protocol is most accurate for extended peptides of limited size and number of formal charges, defining a domain of applicability for this approach.

A detailed understanding of the molecular and cellular mechanisms that underlie epitope preferences in T cell priming is important for vaccines designed to elicit a broad T cell response. Protein vaccinations generally elicit CD4 T cell responses that are skewed toward a small fraction of epitopes, a phenomenon known as immunodominance. This characteristic of T cell responses, which limits the diversity of CD4 T cell recognition, is generally attributed to intracellular Ag processing. However, we recently discovered that immunodominance hierarchies persist even after vaccination with synthetic peptides. In this study, we probed the regulatory mechanisms that cause diminished CD4 T cell responses to subdominant peptides after such multipeptide immunization in mice. We have found that the delivery of subdominant and dominant epitopes on separate dendritic cells rescues expansion of less favored CD4 T cells. Furthermore, through the use of genetic models and inhibitors, we have found that selective losses in CD4 T cell responses are mediated by an IFN-γ-induced pathway, involving IDO, and that regulatory T cell activities may also regulate preferences in CD4 T cell specificity. We propose that after multipeptide immunization, the expansion and differentiation of dominant T cells initiate complex regulatory events that determine the final peptide specificity of the elicited CD4 T cell response.

Rapid advances in immune system knowledge have led to the exploration of immunologic approaches for eliminating tumor cells. Human telomerase reverse transcriptase (hTERT) is considered to be an ideal universal target for novel immunotherapies against cancers. Thus far, studies of effective antitumor immunotherapies have focused on the quantity and quality of the effector function of the CD8 compartment. However, increasing evidence has demonstrated that CD4+ T cells play important roles in generating and maintaining antitumor immune responses in animal models. The aim of this work was to verify whether diepitope multiple antigen peptides (MAPs) that were composed of the cytotoxic T lymphocyte (CTL) epitope of hTERT and the T-helper epitope of hTERT could improve upon the immunogenicity of a monoepitope MAP of hTERT. Dendritic cells (DCs) pulsed with diepitope MAPs composed of the CTL epitope hTERT-540 and the T-helper epitope hTERT-766 were used to evaluate immune responses against various tumor cells. A standard in vitro 4-h ⁵¹Cr-release assay was employed in this study. The results demonstrated that CTLs activated by the diepitope MAP that consisted of hTERT-540 and hTERT-766 could cause 8.56% more lysis than CTLs activated by the monoepitope MAP containing hTERT-540. Moreover, the activated CTLs could kill neither hTERT-negative tumor cells, such as U2OS cells, nor HLA-A2 negative cells, such as HepG2 cells. Our results indicate that diepitope MAPs that are generated from hTERT can be exploited for cancer immunotherapy.

Pancreatic cancer (PC) represents an unresolved therapeutic challenge, due to the poor prognosis and the reduced response to currently available treatments. Pancreatic cancer is the most lethal type of digestive cancers, with a median survival of 4-6 months. Only a small proportion of PC patients is curative by surgical resection, whilst standard chemotherapy for patients in advanced disease generates only modest effects with considerable toxic damages. Thus, new therapeutic approaches, specially specific treatments such as immunotherapy, are needed. In this paper we analyze recent preclinical and clinical efforts towards immunotherapy of pancreatic cancer, including passive and active immunotherapy approaches, designed to target pancreatic-cancer-associated antigens and to elicit an antitumor response in vivo.

The development of peptide vaccines aimed at enhancing immune responses against tumor cells is becoming a promising area of research. Human telomerase reverse transcriptase (hTERT) is an ideal universal target for novel immunotherapies against cancers. The aim of this work was to verify whether the multiple antigen peptides (MAP) based on HLA-A0201-restricted CTL epitopes of hTERT could trigger a better and more sustained CTL response and kill multiple types of hTERT-positive tumor cells in vitro and ex vivo. Dendritic cells (DC) pulsed with MAP based on HLA-A0201-restricted CTL epitopes of hTERT (hTERT-540, hTERT-865 and hTERT-572Y) were used to evaluate immune responses against various tumors and were compared to the immune responses resulting from the use of corresponding linear epitopes and a recombinant adenovirus-hTERT vector. A 4-h standard (51) Cr-release assay and an ELISPOT assay were used for both in vitro and ex vivo analyses. Results demonstrated that targeting hTERT with an adenovector was the most effective way to stimulate a CD8(+) T cell response. When compared with linear hTERT epitopes, MAP could trigger stronger hTERT-specific CTL responses against tumor cells expressing hTERT and HLA-A0201. In contrast, the activated CTL could neither kill the hTERT-negative tumor cells, such as U2OS cells, nor kill HLA-A0201 negative cells, such as HepG2 cells. We also found that these peptide-specific CTL could not kill autologous lymphocytes and DC with low telomerase activity. Our results indicate that MAP from hTERT can be exploited for cancer immunotherapy.

Here, we review potential determinants of the anticancer efficacy of innate immune peptides (ACPs) for cancer cells. These determinants include membrane-based factors, such as receptors, phosphatidylserine, sialic acid residues, and sulfated glycans, and peptide-based factors, such as residue composition, sequence length, net charge, hydrophobic arc size, hydrophobicity, and amphiphilicity. Each of these factors may contribute to the anticancer action of ACPs, but no single factor(s) makes an overriding contribution to their overall selectivity and toxicity. Differences between the anticancer actions of ACPs seem to relate to different levels of interplay between these peptide and membrane-based factors.

As the prevalence of cancer and transmittable disease persists, the development of new and more advanced therapies remains a priority in medical research. An emerging platform for the treatment of these illnesses is the use of materials formed via peptide assembly where the bulk material itself acts as the therapeutic. Higher ordered peptide structures with defined chemistry are capable of cellular targeting, recognition, and internalization. Recent design efforts are being made to exploit the nanoscale definition of the materials formed by assembling peptides to target cancer and microbial cells and to function as vaccines. This review focuses on assembled peptide materials that actively participate in the biological processes important to cancer and transmittable diseases to exert an anticipated functional outcome.

At present, immunotherapy in urological malignancy is experiencing a renaissance, particularly with the emergence of a host of innovative cancer vaccines. Herein, we will review promising immunotherapeutic approaches and evaluate the data supporting their inclusion in novel combination strategies.

Antimicrobial peptides have been considered as potential candidates for cancer therapy. We report here the cytotoxicity of a library of 66 antibacterial cyclodecapeptides on human carcinoma cell lines, and their effects on apoptosis [as assessed by cleavage of poly(ADP-ribose) polymerase (PARP)] and cell signaling proteins (p53 and ERK1/2) in cultured human cervical carcinoma cells. A design of experiments approach permitted to analyze the results of a subset of 16 peptides and define rules for high anticancer activity against MDA-MB-231 breast carcinoma cells. Eight peptides were identified with IC(50) values ranging from 18.5 to 57.5 μM against the five cell lines tested, being HeLa cells the most sensitive. Among these sequences, BPC88, BPC96, BPC98, and BPC194 displayed specificity and high cytotoxicity against HeLa cells (IC(50) of 22.5-38.5 μM), showed low hemolytic activity and low cytotoxicity to non-malignant fibroblasts, and were stable to proteases in human serum. Induction of apoptosis by these peptides was observed and the apoptotic effect of BPC88 and BPC96 caused a marked decrease on the activated form of ERK1/2 kinase and an induction of p53. We further showed that BPC96 at low doses synergized the cytotoxic effect of cisplatin. These findings suggest that cyclic decapeptides may represent novel anticancer agents providing a new strategy in cancer therapy.

Modulation of the immune system for therapeutic ends has a long history, stretching back to Edward Jenner's use of cowpox to induce immunity to smallpox in 1796. Since then, immunotherapy, in the form of prophylactic and therapeutic vaccines, has enabled doctors to treat and prevent a variety of infectious diseases, including cholera, poliomyelitis, diphtheria, measles and mumps. Immunotherapy is now increasingly being applied to oncology. Cancer immunotherapy attempts to harness the power and specificity of the immune system for the treatment of malignancy. Although cancer cells are less immunogenic than pathogens, the immune system is capable of recognizing and eliminating tumor cells. However, tumors frequently interfere with the development and function of immune responses. Thus, the challenge for cancer immunotherapy is to apply advances in cellular and molecular immunology and develop strategies that effectively and safely augment antitumor responses.

Multiple myeloma (MM) is a clonal B-cell malignancy with many fatal clinical sequelae. Despite extensive therapeutic approaches, cures remain rare exceptions. A recent promising area of investigation is the development of immunotherapeutic approaches that target and eliminate myeloma cells more selectively. Because of its potential to promote the destruction of cancerous cells via cytotoxic T-cell responses, peptide-based immunotherapy is one of these strategies to have attracted considerable attention. Furthermore, many studies were carried out to identify the best epitope peptides, the optimal vaccine formulation and schedule, and the preferable clinical situation for vaccination. Based on these results, various epitope peptides have been identified that may be selectively targeted by host immunity, and various approaches have been used to enhance the immune responses of peptides. This chapter focuses on reviewing previous immunotherapy trials, describing the current strategies for peptide-based immunotherapy, and discussing the achievable prospects in MM.

DNA-based cancer vaccines represent an attractive strategy for inducing immunity to tumor associated antigens (TAAs) in cancer patients. The demonstration that the delivery of a recombinant plasmid encoding epitopes can lead to epitope production, processing, and presentation to CD8+ T-lymphocytes, and the advantage of using a single DNA construct encoding multiple epitopes of one or more TAAs to elicit a broad spectrum of cytotoxic T-lymphocytes has encouraged the development of a variety of strategies aimed at increasing immunogenicity of TAA polyepitope DNA-based vaccines. The polyepitope DNA-based cancer vaccine approach can (a) circumvent the variability of peptide presentation by tumor cells, (b) allow the introduction in the plasmid construct of multiple immunogenic epitopes including heteroclitic epitope versions, and (c) permit to enroll patients with different major histocompatibility complex (MHC) haplotypes. This review will discuss the rationale for using the TAA polyepitope DNA-based vaccination strategy and recent results corroborating the usefulness of DNA encoding polyepitope vaccines as a potential tool for cancer therapy.

Host defence peptides (HDP) produced by almost all species of living organisms and widely recognized as antimicrobial antibiotics have also proved to be capable of killing a wide variety of cancer cells. In this respect they have many advantages over conventional cytotoxic chemotherapeutic agents. They seem to kill cancer cells by effects on plasma membranes and/or the membranes of mitochondria. They are often effective against multidrug-resistant cells. They have a broad spectrum of activity in that their killing effects are not restricted to particular kinds of cancer. Above all they commonly have few side effects in that they do not have the same detrimental effects on normal cells as they do on cancer cells. It has been demonstrated that HDP can be used as effective adjuvants to conventional chemotherapeutic agents. In addition they have effects on neo-angiogenesis which is important in relation to tumour growth. HDP have been shown to be powerful immunomodulators in a number of circumstances and in this respect they are believed to be instrumental in strengthening immunological host defence against cancer cells. Importantly it has also been shown that certain HDP have the capability to alter the capacity of cells to import Ca ions by affecting the location and thus function of calreticulin. Such changes it has been argued are significant in facilitating the killing of tumour cells by immunogical means. HDP constitute a novel class of anticancer agents for which, as we develop better knowledge of their pharmacokinetic profiles and learn better how to tailor their administration, hold high promise to augment or even replace the currently available cytotoxic anticancer chemotherapeutic agents most of which owe their efficacy to their capacity to bind to and damage target cell DNA.