Bone marrow vaccination: a novel approach to enhance antigen specific antitumor immunity.

Bone marrow (BM) serves as a reservoir for a unique population of memory T cells with strong effector properties that make them ideal targets for cancer immunotherapy strategies. However, direct vaccination and priming of T cells within the BM of the host has never been investigated. This study evaluates the specific immune response induced via a new method of direct intra-bone marrow (IBM) vaccination in an animal model of human papillomavirus-associated cancer. We found that IBM vaccinations with the class I HPV-16 E7 epitope induce large numbers of activated, IFN-γ-producing E7-specific lymphocytes in the BM. In prophylactic tumor challenge experiments, direct intra-BM vaccination was found to be protective against tumor formation for 80% of the mice. In the therapeutic setting, IBM vaccination induced tumor regression in 3 of 10 vaccinated mice and delayed tumor growth in the remaining animals. Finally, adoptive transfer of BM cells from IBM vaccinated mice to naïve animals conferred complete protection against tumor growth. These data demonstrate the capacity of direct IBM vaccination to induce potent antigen-specific immunity resulting in protection from tumor growth in an animal model. Specifically targeting BM T cells with vaccines may improve responses to cancer immunotherapy and offer important clinical advantages, especially in the setting of bone marrow malignancies.

Active immunotherapy combined with blockade of a coinhibitory pathway achieves regression of large tumor masses in cancer-prone mice.

Vaccines that aim to expand tumor-specific CD8(+) T cells have yielded disappointing results in cancer patients although they showed efficacy in transplantable tumor mouse models. Using a system that more faithfully mimics a progressing cancer and its immunoinhibitory microenvironment, we here show that in transgenic mice, which gradually develop adenocarcinomas due to expression of HPV-16 E7 within their thyroid, a highly immunogenic vaccine expressing E7 only induces low E7-specific CD8(+) T-cell responses, which fail to affect the size of the tumors. In contrast, the same type of vaccine expressing E7 fused to herpes simplex virus (HSV)-1 glycoprotein D (gD), an antagonist of the coinhibitory B- and T-lymphocyte attenuator (BTLA)/CD160-herpes virus entry mediator (HVEM) pathways, stimulates potent E7-specific CD8(+) T-cell responses, which can be augmented by repeated vaccination, resulting in initial regression of even large tumor masses in all mice with sustained regression in more than half of them. These results indicate that active immunization concomitantly with blockade of the immunoinhibitory HVEM-BTLA/CD160 pathways through HSV-1 gD may result in sustained tumor regression.

Effect of a novel DNA vaccine on angiogenesis and tumor growth in vivo.

OBJECTIVE: To develop a DNA cancer vaccine that targets the vascular endothelial growth factor receptor. DESIGN: Mice were vaccinated intramuscularly with listeriolysin O-fetal liver kinase 1 (LLO-Flk1) or controls. Mice were also challenged subcutaneously with the tumor cell line TC-1. Tumor sizes were measured after vaccination. At the conclusion of the experiments, the tumors were harvested for immunohistochemical analysis and determination of hemoglobin content. SETTING: Research laboratory. SUBJECTS: Six- to 8-week-old C57BL/6 mice. INTERVENTION: Fifty micrograms of each vector was administered 3 times at weekly intervals. MAIN OUTCOME MEASURES: Tumor size, mean vessel density of tumors, hemoglobin content of tumor. RESULTS: Mice treated with the LLO-Flk1 vaccine experienced slower tumor growth relative to the other treatment groups. Complete tumor regression was observed in several cases. Immunohistochemical staining of tumors revealed fewer blood vessels in the mice vaccinated with the LLO-Flk1 vaccine relative to the other treatment groups. Finally, colorimetric assessment for hemoglobin suggested decreased vasculature in the tumor bed of these mice relative to the control groups. CONCLUSION: The novel DNA cancer vaccine LLO-Flk1 can slow tumor growth in vivo.

Synthetic peptide-based cancer vaccines: lessons learned and hurdles to overcome.

In the vast majority of studies conducted to date, activation of cancer-specific T cell immunity through peptide-based immunization has failed to induce objective tumor regression. This failure is particularly troublesome given that these vaccines often stimulate T cell responses. In this review, we attempt to understand the relative failure of peptide cancer vaccines to achieve clinically meaningful responses. In the first part of the review, we discuss specific hurdles to successful application of synthetic peptide-based vaccines including patient variability and epitope selection. In the second part of this review, we summarize the importance of CD4+ T cell help in peptide-based vaccine strategies and offer a potential strategy to improve peptide-based vaccines through the generation of both HLA class I and class II vaccine specific-immune responses.

Listeria-based HPV-16 E7 vaccines limit autochthonous tumor growth in a transgenic mouse model for HPV-16 transformed tumors.

We have shown that Listeria-based cancer vaccines inhibit the growth of transplanted tumors in a transgenic mouse model of immune tolerance where HPV-16 E7 is expressed in the thyroid gland. In this study we determine whether these vaccines are able to inhibit autochthonous tumor growth in this animal model. Mice treated with Listeria vaccines expressing E7 had significantly smaller thyroid tumors than did mice treated with controls and possessed higher numbers of antigen-specific CD8(+) T cells within the spleens, tumors, and peripheral blood. This study shows that Listeria-based vaccines are able to slow autochthonous tumor growth and break immunological tolerance.

Increased viral load correlates with improved survival in HPV-16-associated tonsil carcinoma patients.

CONCLUSION: Our results indicate that viral load may serve as an independent prognostic indicator for patients with HPV-16-associated squamous cell carcinoma of the tonsil. OBJECTIVE: HPV-16 has gained increasing attention as a possible causative agent for squamous cell carcinoma of the tonsil. Recent reports have indicated that the viral load within the tumor, along with other factors, may be correlated to the patient survival. In this study, we sought to examine HPV-16 viral load as an independent prognostic indicator. PATIENTS AND METHODS: DNA was extracted from 35 tonsil carcinoma samples and the viral load was determined by real-time PCR. The patients were divided into four groups according to HPV-16 viral load. The correlation between viral load and recurrence, disease-free survival, and overall survival was assessed. RESULTS: We found that HPV-positive patients with the highest viral loads had improved overall and disease-free survival. Recurrences of squamous cell carcinoma were significantly less likely to occur with increasing viral load.

Prognostic significance of tumor-infiltrating lymphocytes in oropharyngeal cancer.

The presence of tumor-infiltrating lymphocytes has been shown to significantly improve clinical outcomes in many types of cancer. However; their effects on outcomes in patients with oropharyngeal cancer specifically have yet to be elucidated. We conducted a retrospective study in an effort to shed light on this issue. We reviewed the records of 48 consecutively presenting patients with oropharyngeal cancer; and we performed immunohistochemistry to analyze their archived paraffin-embedded tissue samples for the presence of CD3-positive tumor-infiltrating lymphocytes. We also used real-time polymerase chain reaction testing to look for human papillomavirus type 16 (HPV-16) in the tumors. We found that patients with large numbers of tumor-infiltrating lymphocytes (CD3high) had a significantly lower incidence of metastasis at presentation than did those with low numbers of tumor-infiltrating lymphocytes (CD31low) (40.0 vs. 88.5%; p = 0.001), regardless of HPV status. When HPV status was taken into account, the correlation between a high CD3 count and a lower rate of metastasis was maintained in the HPV-positive patients but not in the HPV-negative patients. We also found that the CD3high patients had higher rates of overall survival and disease-free survival at 3 and 5 years than did the CD3low patients; however; these differences only approached but did not reach statistical significance.

Listeria-based vaccines can overcome tolerance by expanding low avidity CD8+ T cells capable of eradicating a solid tumor in a transgenic mouse model of cancer.

We have created a transgenic mouse with tissue-specific expression of the human papilloma virus (HPV) 16 E6 and E7 oncoproteins in the thyroid as a model of HPV transformed cancer. The expression of the transgenes results in the formation of palpable thyroid tumors. E7 is not expressed in other tissues but is expressed in medullary thymic epithelial cells, which have been implicated in the control of negative selection. We show that Listeria-based vaccines against E7 can induce the regression of solid implanted tumors in the transgenic mice, although at a lower frequency than in wild type (WT) mice. E7-specific CD8+ T cells induced in transgenic mice are of both lower avidity and lower frequency when compared to the WT mice. In this model, Listeria-based vaccines against E7 appear to be overcoming central tolerance by expanding low avidity CD8+ T cells specific for E7 that are not deleted during thymopoesis and can eliminate solid tumors.

Proteomic signatures in laryngeal squamous cell carcinoma.

Laryngeal cancer remains a worldwide health problem. The identification of biomarkers unique to laryngeal cancer may provide new insights into its pathogenesis, as well as provide potential targets for novel therapies and early detection. In order to identify potential biomarkers, we performed a proteomic analysis of laryngeal cancer specimens. Using two-dimensional differential in-gel electrophoresis and mass spectroscopy, protein expression profiles from two laryngeal carcinoma specimens and corresponding adjacent normal tissue were analyzed. The results of our analysis showed that the expression of a number of proteins was significantly altered in the tumor specimens when compared to matched normal controls. The differentially expressed proteins were identified, and they included stratifin, S100 calcium-binding protein A9, p21-ARC, stathmin, and enolase. With these findings, we have identified potential biomarkers which may contribute to the pathogenesis of laryngeal carcinoma, and which may be suitable as targets for novel therapeutic and/or diagnostic modalities.

Genome-wide profiling of oral squamous cell carcinoma by array-based comparative genomic hybridization.

OBJECTIVES: Array-based comparative genomic hybridization (aCGH) was used to develop a genome-wide molecular profile of oral squamous cell carcinoma (OSCC). Copy number alterations (CNAs) were identified by chromosomal region, mapped to specific genes, and compared with several previously documented CNAs associated with head and neck squamous cell carcinoma (HNSCC). The status of 512 commonly altered cancer genes was assessed and evaluated as potential correlates of tumor behavior. METHODS: Tumor tissue DNA was isolated for aCGH from 21 prospectively collected fresh-frozen OSCC specimens. aCGH was performed at 0.9-Mb resolution to identify distinct regions of genomic alteration and their associated genes. Cancer genes commonly altered were then correlated with clinicopathologic tumor data. RESULTS: Genomic regions most frequently amplified (>35%) were located on 3q, 5p, 8q, 9q, and 20q, although regions most frequently deleted (>40%) involved chromosomes 3p, 8p, 13q, and 18q. Minimal regions of CNA identified, by aCGH narrowed larger, previously documented CNAs associated with HNSCC to significantly smaller regions, yielding shorter lists of candidate genes. Cancer-related genes altered in greater than 25% OSCC samples were identified (22 amplified, 17 deleted). Several genes associated with the Fanconi anemia DNA-damage response pathway were frequently altered, including BRCA1, BRCA2, FANCD2, and FANCG. Other cancer-related genes linked to hereditary cancer syndromes include VHL, MLH1, XPC, and RB1. CONCLUSIONS: Genome-wide aCGH can be used to detect and map CNAs in OSCC tissue specimens with high resolution. These data implicate several candidate genes and gene pathways in the tumorigenesis of sporadic OSCC.

Vaccination with human papillomavirus type 16 E7 peptide with CpG oligonucleotides for prevention of tumor growth in mice.

OBJECTIVE: To test whether an E7 peptide/CpG vaccine is effective in preventing and treating human papillomavirus-positive tumors in a murine model. INTERVENTION: First, an E7 peptide/CpG vaccine was administered systemically on days -14 and -7, and tumor cells were injected subcutaneously on day 0. Second, tumor cells were injected on day 0, and vaccine was administered on days 7, 14, and 21. MAIN OUTCOME MEASURES: Tumor size was measured 3 times per week. A tetramer assay was used to assess the presence of activated, E7-specific lymphocytes in spleen and tumor cells harvested from mice treated with a similar vaccination regimen. RESULTS: In the prophylactic study, 75% of mice injected with E7 peptide/CpG resisted tumor formation. In the therapeutic setting, tumors initially regressed and experienced delayed progression when compared with controls. Survival rates improved in E7/CpG-vaccinated mice. Tetramer analysis detected increased numbers of activated, E7-specific lymphocytes in the spleens and tumors of animals treated with the experimental vaccine when compared with controls. CONCLUSION: The use of CpG motifs as an adjunct to peptide-based immunotherapy has potential impact on the treatment of human papillomavirus-associated cancers.

Recombinant Listeria vaccines containing PEST sequences are potent immune adjuvants for the tumor-associated antigen human papillomavirus-16 E7.

Previous work in our laboratory has established that the fusion of tumor-associated antigens to a truncated form of the Listeria monocytogenes virulence factor listeriolysin O (LLO) enhances the immunogenicity and antitumor efficacy of the tumor antigen when delivered by Listeria or by vaccinia. LLO contains a PEST sequence at the NH(2) terminus. These sequences, which are found in eukaryotic proteins with a short cellular half-life, target proteins for degradation in the ubiquitin-proteosome pathway. To investigate whether the enhanced immunogenicity conferred by LLO is due to the PEST sequence, we constructed new Listeria recombinants that expressed the HPV-16 E7 antigen fused to LLO, which either contained or had been deleted of this sequence. We then compared the antitumor efficacy of this set of vectors and found that Listeria expressing the fusion protein LLO-E7 or PEST-E7 were effective at regressing established macroscopic HPV-16 immortalized tumors in syngeneic mice. In contrast, Listeria recombinants expressing E7 alone or E7 fused to LLO from which the PEST sequence had been genetically removed could only slow tumor growth. Because CD8(+) T cell epitopes are generated in the ubiquitin-proteosome pathway, we also investigated the ability of the vaccines to induce E7-specific CD8(+) T cells in the spleen and to generate E7-specific tumor-infiltrating lymphocytes. A strong correlation was observed between CD8(+) T-cell induction and tumor homing and the antitumor efficacy of the Listeria-E7 vaccines. These findings suggest a strategy for the augmentation of tumor antigen-based immunotherapeutic strategies that may be broadly applicable.

Regression of HPV-positive tumors treated with a new Listeria monocytogenes vaccine.

BACKGROUND: Human papillomavirus (HPV) has been implicated in the pathogenesis of 15% to 23% of head and neck squamous cell carcinomas as well as most oropharyngeal carcinomas. The viral oncoproteins E6 and E7 are expressed in HPV-positive tumor cells and therefore provide ideal targets for tumor immunotherapy. Because of its unique ability to induce a cellular immune response, the intracellular bacteria Listeria monocytogenes has been studied as a potential HPV-positive tumor vaccine. OBJECTIVE: To present a new recombinant strain of L monocytogenes that is effective in treating HPV-positive tumors in a murine model. DESIGN: A new recombinant L monocytogenes vaccine, Lm-ActA-E7, was designed by transforming an attenuated Listeria strain with an E7 expression cassette. The cassette consists of the HPV-16 E7 sequence fused to the Listeria protein ActA. The resultant strain of bacteria secretes E7 antigen as a fusion protein with ActA. METHODS: Tumors were established in C57BL/6 mice with a syngeneic HPV-positive cell line prior to treatment with vaccine. INTERVENTION: The Lm-ActA-E7 vaccine was administered intraperitoneally to the mice 5 days after tumors were established. A booster dose was administered 7 days after the first dose. Tumor progression was measured in 2 dimensions periodically after the vaccination. RESULTS: In C57BL/6 mice, the administration of Lm-ActA-E7 caused the complete regression of HPV-positive tumors in 6 of 8 mice tested. A cytotoxic T-lymphocyte assay revealed that administration of the vaccine caused the generation of cytotoxic T cells specific for E7. CONCLUSION: Our results demonstrate the ability of a new Listeria-based vaccine to generate a specific antitumor T-cell response and cause the regression of HPV-positive tumors in a murine model.

Hypothermia during head and neck surgery.

OBJECTIVE: To determine the predictors and incidence of hypothermia in patients undergoing head and neck surgery. STUDY DESIGN: Retrospective analysis. METHODS: Patients were either not warmed (n = 43) or actively warmed with forced-air warming (n = 25). Clinical variables that were assessed as predictors of core body temperature included age, body mass, duration of procedure, estimated blood loss, amount of intravenous fluids administered, and the use of forced-air warming. The incidence of severe intraoperative hypothermia and potential hypothermia-related complications was also examined. RESULTS: The study demonstrated that advanced age is a risk factor for hypothermia and decreased body mass is associated with lower final body temperatures in the groups of patients that was not warmed. After adjusting for differences in the ages and weights between the two groups, the mean core body temperature was found to be 0.4 degrees C lower in the patients who were not warmed. Severe intraoperative hypothermia occurred in 5 of 38 patients (11.6%) who were not warmed and 2 of 23 patients (8.0%) who were warmed. The complications associated with hypothermia included delayed time to extubation, the development of neck seromas, and flap dehiscence. CONCLUSIONS: Patients undergoing head and neck surgery are at risk for the development of intraoperative hypothermia and require careful temperature monitoring. Elderly patients and patients with low body mass are more prone to develop low intraoperative core body temperatures. Active warming with forced-air warmers should be considered for patients at risk for intraoperative hypothermia and for patients who develop hypothermia intraoperatively, to avoid hypothermia-related complications.