Immunity to the HER-2/neu oncogenic protein

Is It Possible to Develop Cancer Vaccines to Neoantigens, What Are the Major Challenges, and How Can These Be Overcome? Neoantigens: Nothing New in Spite of the Name

The term "neoantigen," as applied to molecules newly expressed on tumor cells, has a long history. The groundbreaking discovery of a cancer causing virus in chickens by Rous over 100 years ago, followed by discoveries of other tumor-causing viruses in animals, suggested a viral etiology of human cancers. The search for other oncogenic viruses in the 1960s and 1970s resulted in the discoveries of Epstein-Barr virus (EBV), hepatitis B virus (HBV), and human papilloma virus (HPV), and continues until the present time. Contemporaneously, the budding field of immunology was posing the question can the immune system of animals or humans recognize a tumor that develops from one's own tissues and what types of antigens would distinguish the tumor from normal cells. Molecules encoded by oncogenic viruses provided the most logical candidates and evidence was quickly gathered for both humoral and cellular recognition of viral antigens, referred to as neoantigens. Often, however, serologic responses to virus-bearing tumors revealed neoantigens unrelated to viral proteins and expressed on multiple tumor types, foreshadowing later findings of multiple changes in other genes in tumor cells creating nonviral neoantigens.

Serum prognostic biomarkers in head and neck cancer patients

OBJECTIVES/HYPOTHESIS

A reliable estimate of survival is important as it may impact treatment choice. The objective of this study is to identify serum autoantibody biomarkers that can be used to improve prognostication for patients affected with head and neck squamous cell carcinoma (HNSCC).

STUDY DESIGN

Prospective cohort study.

METHODS

A panel of 130 serum biomarkers, previously selected for cancer detection using microarray-based serological profiling and specialized bioinformatics, were evaluated for their potential as prognostic biomarkers in a cohort of 119 HNSCC patients followed for up to 12.7 years. A biomarker was considered positive if its reactivity to the particular patient's serum was greater than one standard deviation above the mean reactivity to sera from the other 118 patients, using a leave-one-out cross-validation model. Survival curves were estimated according to the Kaplan-Meier method, and statistically significant differences in survival were examined using the log rank test. Independent prognostic biomarkers were identified following analysis using multivariate Cox proportional hazards models.

RESULTS

Poor overall survival was associated with African Americans (hazard ratio [HR] for death = 2.61; 95% confidence interval [CI]: 1.58-4.33; P = .000), advanced stage (HR = 2.79; 95% CI: 1.40-5.57; P = .004), and recurrent disease (HR = 6.66; 95% CI: 2.54-17.44; P = .000). On multivariable Cox analysis adjusted for covariates (race and stage), six of the 130 markers evaluated were found to be independent prognosticators of overall survival.

CONCLUSIONS

The results shown here are promising and demonstrate the potential use of serum biomarkers for prognostication in HNSCC patients. Further clinical trials to include larger samples of patients across multiple centers may be warranted.

Autoantibodies against MMP-7 as a novel diagnostic biomarker in esophageal squamous cell carcinoma

AIM: To evaluate the diagnostic values of serum autoantibodies against matrix metalloproteinase-7 (MMP-7) in patients with esophageal squamous cell carcinoma (ESCC).

METHODS: The MMP-7 cDNA was cloned from ESCC tissues, and MMP-7 was expressed and purified from a prokaryotic system. MMP-7 autoantibodies were then measured in sera from 50 patients with primary ESCC and 58 risk-matched controls, using a reverse capture enzyme-linked immunosorbent assay (ELISA) in which autoantibodies to MMP-7 bound to the purified MMP-7 proteins. In addition, MMP-7 autoantibody levels in sera from 38 gastric cancer patients and from control serum samples were also tested.

RESULTS: The optimum conditions for recombinant MMP-7 protein expression were determined as 0.04 mmol/L Isopropyl-β-D-Thiogalactopyranoside (IPTG) induction at 37°C for four hours. The levels of serum autoantibodies against MMP-7 were significantly higher in patients with ESCC than in the matched-control samples (OD450 = 1.69 ± 0.08 vs OD450 = 1.55 ± 0.10, P < 0.001). The area under the receiver operating characteristic (ROC) curve was 0.87. The sensitivity and specificity for detection of ESCC were 78.0% and 81.0%, respectively, when the OD450 value was greater than 1.65. Although the levels of autoantibodies against MMP-7 were also significantly higher in patients with gastric cancer compared to control samples (OD450 = 1.62 ± 0.06 vs OD450 = 1.55 ± 0.10, P < 0.001), the diagnostic accuracy was less significant than in ESCC patients. The area of ROC curve was 0.75, whereas the sensitivity and specificity were 60.5% and 71.7%, respectively, when the cut-off value of OD450 was set at 1.60.

CONCLUSION: Serum autoantibody levels of MMP-7 may be a good diagnostic biomarker for esophageal squamous cell carcinoma.

A chaperone protein-enriched tumor cell lysate vaccine generates protective humoral immunity in a mouse breast cancer model

We have documented previously that a multiple chaperone protein vaccine termed chaperone-rich cell lysate (CRCL) promotes tumor-specific T-cell responses leading to cancer regression in several mouse tumor models. We report here that CRCL vaccine generated from a mouse breast cancer (TUBO, HER2/neu positive) is also capable of eliciting humoral immunity. Administration of TUBO CRCL triggered anti-HER2/neu antibody production and delayed the progression of established tumors. This antitumor activity can be transferred through the serum isolated from TUBO CRCL-immunized animals and involved both B cells and CD4(+) T lymphocytes. Further evaluation of the mechanisms underlying TUBO CRCL-mediated humoral immunity highlighted the role of antibody-dependent cell-mediated cytotoxicity. These results suggest that tumor-derived CRCL vaccine has a wider applicability as a cancer vaccine because it can target both T-cell- and B-cell-specific responses and may represent a promising approach for the immunotherapy of cancer.

Autoantibody approach for serum-based detection of head and neck cancer

Currently, no effective tool exists for screening or early diagnosis of head and neck squamous cell carcinoma (HNSCC). Here, we describe an approach for cancer detection based on analysis of patterns of serum immunoreactivity against a panel of biomarkers selected using microarray-based serologic profiling and specialized bioinformatics. We biopanned phage display libraries derived from three different HNSCC tissues to generate 5,133 selectively cloned tumor antigens. Based on their differential immunoreactivity on protein microarrays against serum immunoglobulins from 39 cancer and 41 control patients, we reduced the number of clones to 1,021. The performance of a neural network model (Multilayer Perceptron) for cancer classification on a data set of 80 HNSCC and 78 control samples was assessed using 10-fold cross-validation repeated 100 times. A panel of 130 clones was found to be adequate for building a classifier with sufficient sensitivity and specificity. Using these 130 markers on a completely new and independent set of 80 samples, an accuracy of 84.9% with sensitivity of 79.8% and specificity of 90.1% was achieved. Similar performance was achieved by reshuffling of the data set and by using other classification models. The performance of this classification approach represents a significant improvement over current diagnostic accuracy (sensitivity of 37% to 46% and specificity of 24%) in the primary care setting. The results shown here are promising and show the potential use of this approach toward eventual development of diagnostic assay with sufficient sensitivity and specificity suitable for detection of early-stage HNSCC in high-risk populations.

Cross-priming of cyclin B1, MUC-1 and survivin-specific CD8+ T cells by dendritic cells loaded with killed allogeneic breast cancer cells

Introduction

The ability of dendritic cells (DCs) to take up whole tumor cells and process their antigens for presentation to T cells ('cross-priming') is an important mechanism for induction of tumor specific immunity.

Methods

In vitro generated DCs were loaded with killed allogeneic breast cancer cells and offered to autologous naïve CD8⁺ T cells in 2-week and/or 3-week cultures. CD8⁺ T cell differentiation was measured by their capacity to secrete effector cytokines (interferon-γ) and kill breast cancer cells. Specificity was measured using peptides derived from defined breast cancer antigens.

Results

We found that DCs loaded with killed breast cancer cells can prime naïve CD8⁺ T cells to differentiate into effector cytotoxic T lymphocytes (CTLs). Importantly, these CTLs primed by DCs loaded with killed HLA-A*0201^- breast cancer cells can kill HLA-A*0201⁺ breast cancer cells. Among the tumor specific CTLs, we found that CTLs specific for HLA-A2 restricted peptides derived from three well known shared breast tumor antigens, namely cyclin B1, MUC-1 and survivin.

Conclusion

This ability of DCs loaded with killed allogeneic breast cancer cells to elicit multiantigen specific immunity supports their use as vaccines in patients with breast cancer.

Immunization with a HER-2/neu helper peptide vaccine generates HER-2/neu CD8 T-cell immunity in cancer patients

CD4 T-cell help is required during the generation and maintenance of effective antitumor CD8 T cell-mediated immunity. The goal of this study was to determine whether HER-2/neu-specific CD8 T-cell immunity could be elicited using HER-2/neu-derived MHC class II "helper" peptides, which contain encompassed HLA-A2-binding motifs. Nineteen HLA-A2 patients with HER-2/neu-overexpressing cancers received a vaccine preparation consisting of putative HER-2/neu helper peptides p369-384, p688-703, and p971-984. Contained within these sequences are the HLA-A2-binding motifs p369-377, p689-697, and p971-979. After vaccination, the mean peptide-specific T-cell precursor frequency to the HLA-A2 peptides increased in the majority of patients. In addition, the peptide-specific T cells were able to lyse tumors. The responses were long-lived and detectable for more than 1 year after the final vaccination in select patients. These results demonstrate that HER-2/neu MHC class II epitopes containing encompassed MHC class I epitopes are able to induce long-lasting HER-2-specific IFN-gamma-producing CD8 T cells.