Immune responses to all ErbB family receptors detectable in serum of cancer patients

ErbB3 Governs Endothelial Dysfunction in Hypoxia-Induced Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension, characterized by vascular remodeling, currently lacks curative therapeutic options. The dysfunction of pulmonary artery endothelial cells plays a pivotal role in the initiation and progression of pulmonary hypertension (PH). ErbB3 (human epidermal growth factor receptor 3), also recognized as HER3, is a member of the ErbB family of receptor tyrosine kinases.

METHODS

Microarray, immunofluorescence, and Western blotting analyses were conducted to investigate the pathological role of ErbB3. Blood samples were collected for biomarker examination from healthy donors or patients with hypoxic PH. The pathological functions of ErbB3 were further validated in rodents subjected to chronic hypoxia- and Sugen-induced PH, with or without adeno-associated virus-mediated ErbB3 overexpression, systemic deletion, or endothelial cell-specific ErbB3 knockdown. Primary human pulmonary artery endothelial cells and pulmonary artery smooth muscle cells were used to elucidate the underlying mechanisms.

RESULTS

ErbB3 exhibited significant upregulation in the serum, lungs, distal pulmonary arteries, and pulmonary artery endothelial cells isolated from patients with PH compared with those from healthy donors. ErbB3 overexpression stimulated hypoxia-induced endothelial cell proliferation, exacerbated pulmonary artery remodeling, elevated systolic pressure in the right ventricle, and promoted right ventricular hypertrophy in murine models of PH. Conversely, systemic deletion or endothelial cell-specific knockout of ErbB3 yielded opposite effects. Coimmunoprecipitation and proteomic analysis identified YB-1 (Y-box binding protein 1) as a downstream target of ErbB3. ErbB3 induced nuclear translocation of YB-1 and subsequently promoted hypoxia-inducible factor 1/2α transcription. A positive loop involving ErbB3-periostin-hypoxia-inducible factor 1/2α was identified to mediate the progressive development of this disease. MM-121, a human anti-ErbB3 monoclonal antibody, exhibited both preventive and therapeutic effects against hypoxia-induced PH.

CONCLUSIONS

Our study reveals, for the first time, that ErbB3 serves as a novel biomarker and a promising target for the treatment of PH.

Unraveling the complex interplay between anti-tumor immune response and autoimmunity mediated by B cells and autoantibodies in the era of anti-checkpoint monoclonal antibody therapies

The intricate relationship between anti-tumor immunity and autoimmunity is a complex yet crucial aspect of cancer biology. Tumor microenvironment often exhibits autoimmune features, a phenomenon that involves natural autoimmunity and the induction of humoral responses against self-antigens during tumorigenesis. This induction is facilitated by the orchestration of anti-tumor immunity, particularly within organized structures like tertiary lymphoid structures (TLS). Paradoxically, a significant number of cancer patients do not manifest autoimmune features during the course of their illness, with rare instances of paraneoplastic syndromes. This discrepancy can be attributed to various immune-mediated locks, including regulatory or suppressive immune cells, anergic autoreactive lymphocytes, or induction of effector cells exhaustion due to chronic stimulation. Overcoming these locks holds the risk to induce autoimmune mechanisms during cancer progression, a phenomenon notably observed with anti-immune checkpoint therapies, in contrast to more conventional treatments like chemotherapy or radiotherapy. Therefore, the challenge arises in managing immune-related adverse events (irAEs) induced by immune checkpoint inhibitors treatment, as decoupling them from the anti-tumor activity poses a significant clinical dilemma. This review summarizes recent advances in understanding the link between B-cell driven anti-tumor responses and autoimmune reactions in cancer patients, and discusses the clinical implications of this relationship.

Recent findings on the impact of ErbB receptors status on prognosis and therapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type, has often an aggressive course and is poorly responsive to current therapeutic approaches, so that 5-year survival rates for patients diagnosed with advanced disease is lower than 50%. The Epidermal Growth Factor Receptor (EGFR) has emerged as an established oncogene in HNSCC. Indeed, although HNSCCs are a heterogeneous group of cancers which differ for histological, molecular and clinical features, EGFR is overexpressed or mutated in a percentage of cases up to about 90%. Moreover, aberrant expression of the other members of the ErbB receptor family, ErbB2, ErbB3 and ErbB4, has also been reported in variable proportions of HNSCCs. Therefore, an increased expression/activity of one or multiple ErbB receptors is found in the vast majority of patients with HNSCC. While aberrant ErbB signaling has long been known to play a critical role in tumor growth, angiogenesis, invasion, metastatization and resistance to therapy, more recent evidence has revealed its impact on other features of cancer cells' biology, such as the ability to evade antitumor immunity. In this paper we will review recent findings on how ErbB receptors expression and activity, including that associated with non-canonical signaling mechanisms, impacts on prognosis and therapy of HNSCC.

Effect of autologous NK cell immunotherapy on advanced lung adenocarcinoma with EGFR mutations

This study investigated the efficiency of natural killer (NK) cell immunotherapy on non-small cell lung cancer with and without EGFR mutations in order to evaluate the response rate (RR) and progression-free survival (PFS). Among the 48 patients recruited, 24 were clinically confirmed to be EGFR mutation positive. The study group was treated with autologous NK cell immunotherapy. Comparisons of the lymphocyte number, serum tumour-related biomarkers, circulating tumour cells (CTC), Karnofsky Performance Status (KPS) and survival curves were carried out before and after NK cell immunotherapy. The safety and short-term effects were evaluated, followed by median PFS and RR assessments. The serum CEA and CA125 values were found lower in the NK cell therapy group than that of the non-NK treatment group (p < 0.05). The χ² test showed a 75% RR of the study group A, significantly higher than that of the control group B (16.7%; p < 0.01). The RR of groups C (58.3%) and D (41.7%) were not statistically significant. The p values of the 4 groups were 0.012, 0.012, 0.166 and 1 from group A to group D, respectively. The median PFS was 9 months in EGFR mutation positive group undergoing NK cell infusion interference. By evaluating the changes in immune function, tumour biomarkers, CTC, KPS and PFS, we demonstrated that NK cell therapy had better clinical therapeutic effects on EGFR mutation-positive lung adenocarcinoma.

Evaluation of Protein Levels of the Receptor Tyrosine Kinase ErbB3 in Serum

The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases (RTK) consists of four members: EGFR1/ErbB1/HER1, ErbB2/HER2, ErbB3/HER3, and HER4/ErbB4. Signaling through these receptors regulates many key cellular activities, such as cell division, migration, adhesion, differentiation, and apoptosis. The ErbB family has been shown to be overexpressed in different types of cancers and is a target of several inhibitors already in clinical trials. ErbB3 lacks a functional tyrosine kinase domain and therefore has not been as extensively studied as the other members of this family, but its importance in activating downstream pathways, such as the PI3K/Akt pathway, makes this RTK a worthy investigation target, especially in urothelial carcinoma where the PI3K/Akt pathway is vital for progression. In recent times, ErbB3 overexpression has been linked to drug resistance and progression of various diseases, especially cancer. ErbB3 levels in the serum were shown in many cases to be reflective of its role in disease progression, and therefore detection of serum ErbB3 levels during treatment may be of importance.Here we describe two methods for detecting ErbB3 protein in serum from patients who have undergone a clinical trial, utilizing two well-established methods in molecular biology-western blotting and ELISA, focusing on sample preparation and troubleshooting.

In Vitro and In Vivo Anti-tumoral Effects of the Flavonoid Apigenin in Malignant Mesothelioma

Malignant mesothelioma (MM) is a tumor arising from mesothelium. MM patients’ survival is poor. The polyphenol 4′,5,7,-trihydroxyflavone Apigenin (API) is a “multifunctional drug”. Several studies have demonstrated API anti-tumoral effects. However, little is known on the in vitro and in vivo anti-tumoral effects of API in MM. Thus, we analyzed the in vitro effects of API on cell proliferation, cell cycle regulation, pro-survival signaling pathways, apoptosis, and autophagy of human and mouse MM cells. We evaluated the in vivo anti-tumor activities of API in mice transplanted with MM #40a cells forming ascites. API inhibited in vitro MM cells survival, increased reactive oxygen species intracellular production and induced DNA damage. API activated apoptosis but not autophagy. API-induced apoptosis was sustained by the increase of Bax/Bcl-2 ratio, increase of p53 expression, activation of both caspase 9 and caspase 8, cleavage of PARP-1, and increase of the percentage of cells in subG1 phase. API treatment affected the phosphorylation of ERK1/2, JNK and p38 MAPKs in a cell-type specific manner, inhibited AKT phosphorylation, decreased c-Jun expression and phosphorylation, and inhibited NF-κB nuclear translocation. Intraperitoneal administration of API increased the median survival of C57BL/6 mice intraperitoneally transplanted with #40a cells and reduced the risk of tumor growth. Our findings may have important implications for the design of MM treatment using API.

In vitro and in vivo inhibition of breast cancer cell growth by targeting the Hedgehog/GLI pathway with SMO (GDC-0449) or GLI (GANT-61) inhibitors

Aberrant Hedgehog (Hh)/glioma-associated oncogene (GLI) signaling has been implicated in cancer progression. Here, we analyzed GLI1, Sonic Hedgehog (Shh) and NF-κB expression in 51 breast cancer (ductal carcinoma) tissues using immunohistochemistry. We found a positive correlation between nuclear GLI1 expression and tumor grade in ductal carcinoma cases. Cytoplasmic Shh staining significantly correlated with a lower tumor grade. Next, the in vitro effects of two Hh signaling pathway inhibitors on breast cancer cell lines were evaluated using the Smoothened (SMO) antagonist GDC-0449 and the direct GLI1 inhibitor GANT-61. GDC-0449 and GANT-61 exhibited the following effects: a) inhibited breast cancer cell survival; b) induced apoptosis; c) inhibited Hh pathway activity by decreasing the mRNA expression levels of GLI1 and Ptch and inhibiting the nuclear translocation of GLI1; d) increased/decreased EGFR and ErbB2 protein expression, reduced p21-Ras and ERK1/ERK2 MAPK activities and inhibited AKT activation; and e) decreased the nuclear translocation of NF-κB. However, GANT-61 exerted these effects more effectively than GDC-0449. The in vivo antitumor activities of GDC-0449 and GANT-61 were analyzed in BALB/c mice that were subcutaneously inoculated with mouse breast cancer (TUBO) cells. GDC-0449 and GANT-61 suppressed tumor growth of TUBO cells in BALB/c mice to different extents. These findings suggest that targeting the Hh pathway using antagonists that act downstream of SMO is a more efficient strategy than using antagonists that act upstream of SMO for interrupting Hh signaling in breast cancer.

Identification of the zinc finger 216 (ZNF216) in human carcinoma cells: a potential regulator of EGFR activity

Epidermal Growth Factor Receptor (EGFR), a member of the ErbB family of receptor tyrosine kinase (RTK) proteins, is aberrantly expressed or deregulated in tumors and plays pivotal roles in cancer onset and metastatic progression. ZNF216 gene has been identified as one of Immediate Early Genes (IEGs) induced by RTKs. Overexpression of ZNF216 protein sensitizes 293 cell line to TNF-α induced apoptosis. However, ZNF216 overexpression has been reported in medulloblastomas and metastatic nasopharyngeal carcinomas. Thus, the role of this protein is still not clearly understood. In this study, the inverse correlation between EGFR and ZNF216 expression was confirmed in various human cancer cell lines differently expressing EGFR. EGF treatment of NIH3T3 cells overexpressing both EGFR and ZNF216 (NIH3T3-EGFR/ZNF216), induced a long lasting activation of EGFR in the cytosolic fraction and an accumulation of phosphorylated EGFR (pEGFR) more in the nuclear than in the cytosolic fraction compared to NIH3T3-EGFR cells. Moreover, EGF was able to stimulate an increased expression of ZNF216 in the cytosolic compartment and its nuclear translocation in a time-dependent manner in NIH3T3-EGFR/ZNF216. A similar trend was observed in A431 cells endogenously expressing the EGFR and transfected with Znf216. The increased levels of pEGFR and ZNF216 in the nuclear fraction of NIH3T3-EGFR/ZNF216 cells were paralleled by increased levels of phospho-MAPK and phospho-Akt. Surprisingly, EGF treatment of NIH3T3-EGFR/ZNF216 cells induced a significant increase of apoptosis thus indicating that ZNF216 could sensitize cells to EGF-induced apoptosis and suggesting that it may be involved in the regulation and effects of EGFR signaling.

Potassium increases the antitumor effects of ascorbic acid in breast cancer cell lines in vitro

Ascorbic acid (A) has been demonstrated to exhibit anti-cancer activity in association with chemotherapeutic agents. Potassium (K) is a regulator of cellular proliferation. In the present study, the biological effects of A and K bicarbonate, alone or in combination (A+K), on breast cancer cell lines were evaluated. The survival of cancer cells was determined by sulforhodamine B cell proliferation assay, while analysis of the cell cycle distribution was conducted via fluorescence-activated cell sorting. In addition, the expression of signaling proteins was analyzed upon treatment. The results indicated that there was a heterogeneous response of the different cell lines to A and K, and the best effects were achieved by A+K and A treatment. The interaction between A+K indicated an additive or synergistic effect. In addition, A+K increased the percentage of cells in the sub-G1 phase of the cell cycle, and was the most effective treatment in activating the degradation of poly(adenosine diphosphate-ribose) polymerase-1. In the breast cancer cell line MCF-7, A+K induced the appearance of the 18 kDa isoform of B-cell lymphoma-2-associated X protein (Bax), which is a more potent inducer of apoptosis than the full-length Bax-p21. The effects of A and K on the phosphorylation of extracellular signal-regulated kinase (ERK)1 and ERK2 were heterogeneous. In addition, treatment with K, A and A+K inhibited the expression of nuclear factor-κB. Overall, the results of the present study indicated that K potentiated the anti-tumoral effects of A in breast cancer cells in vitro.

Natural humoral immune response to ribosomal P0 protein in colorectal cancer patients

Background

Tumor associated antigens are useful in colorectal cancer (CRC) management. The ribosomal P proteins (P0, P1, P2) play an important role in protein synthesis and tumor formation. The immunogenicity of the ribosomal P0 protein in head and neck, in breast and prostate cancer patients and the overexpression of the carboxyl-terminal P0 epitope (C-22 P0) in some tumors were reported.

Methods

Sera from 72 colorectal tumor patients (67 malignant and 5 benign tumors) were compared with 73 healthy donor sera for the presence of antibodies to CEA, EGFR, ErbB2 and ribosomal P proteins by western blotting or ELISA. Expression of the C-22 P0 epitope on tissues and colon cancer cells was determined by immunoperoxidase staining and indirect immunofluorescence/western blotting, respectively, employing MAb 2B2. Biological effects of MAb 2B2 on colon cancer cells were assessed by the Sulforhodamine B cell proliferation assay, trypan blue exclusion test and cleaved caspase-3 detection. Fisher’s exact test was used to compare the number of auto-antibodies positive patients with healthy donors. Variation in the C-22 P0 expression, and in the number of apoptotic cells was evaluated by Student’s t-test. Variation in cell survival and cell death was evaluated by Newman-Keuls test.

Results

No significant humoral response was observed to CEA, EGFR and ErbB2 in CRC patients. Conversely, 7 out of 67 CRC patient sera reacted to ribosomal P proteins. The prevalence of P proteins auto-antibodies in CRC patients was significant. Five patients showed restricted P0 immunoreactivity, while two patients reacted simultaneously to all P proteins. The C-22 P0 epitope was homogenously expressed both in malignant tumors and the adjacent mucosa, but the intensity of expression was higher in the tumor. Starved colon cancer cells showed a higher C-22 P0 epitope plasma membrane expression compared to control cells. MAb 2B2 inhibited colon cancer cell growth and induced cell death in a dose dependent manner.

Conclusions

Our study shows a spontaneous humoral immune response to ribosomal P0 protein in CRC patients and the inhibition of in vitro cancer cell growth after C-22 P0 epitope targeting. The ribosomal P0 protein might be a useful immunological target in CRC patients.

Intratumoral delivery of recombinant vaccinia virus encoding for ErbB2/Neu inhibits the growth of salivary gland carcinoma cells

Background

The antitumor activity induced by intratumoral vaccination with poxvirus expressing a tumor antigen was shown to be superior to that induced by subcutaneous vaccination. Salivary gland carcinomas overexpress ErbB2. Trastuzumab, a monoclonal antibody to ErbB2, was proposed for salivary gland tumors treatment. We explored the effectiveness of intratumoral vaccination with the recombinant vaccinia virus ErbB2/Neu (rV-neuT) vaccine in hampering the growth of transplanted Neu-overexpressing BALB-neuT salivary gland cancer cells (SALTO) in BALB-neuT mice.

Methods

BALB-neuT male mice were subcutaneously injected with SALTO tumor cells and intratumorally vaccinated twice with different doses of either rV-neuT or V-wt (wild-type). Tumors were measured weekly. The presence of anti-ErbB2/Neu antibodies was assayed by ELISA, immunoprecipitation or indirect immunofluorescence. Biological activity of immune sera was investigated by analyzing antibody-dependent cellular cytotoxicity (ADCC), SALTO cells proliferation and apoptosis, ErbB2/Neu receptor down regulation and ERK1/2 phosphorylation. Anti-Neu T cell immunity was investigated by determining the release of IL-2 and IFN-gamma in T cells supernatant. Survival curves were determined using the Kaplan-Meier method and compared using the log-rank test. Differences in tumor volumes, number of apoptotic cells, titer of the serum, percentage of ADCC were evaluated through a two-tailed Student’s t-test.

Results

rV-neuT intratumoral vaccination was able to inhibit the growth of SALTO cancer cells in a dose-dependent manner. The anti-Neu serum titer paralleled in vivo antitumor activity of rV-neuT vaccinated mice. rV-neuT immune serum was able to mediate ADCC, inhibition of SALTO cells proliferation, down regulation of the ErbB2/Neu receptor, inhibition of ERK1/2 phosphorylation and induction of apoptosis, thus suggesting potential mechanisms of in vivo tumor growth interference. In addition, spleen T cells of rV-neuT vaccinated mice released IFN-gamma and IL-2 upon in vitro stimulation with several Neu-specific peptides located in the extracellular domain of Neu sequence.

Conclusions

rV-neuT intratumoral vaccination could be employed to induce an efficient antitumor response and reject transplanted salivary gland tumors. Our findings may have important implications for the design of cancer vaccine protocols for the treatment of salivary gland tumors and other accessible tumors using intratumoral injection of recombinant vaccinia virus.

Comparison of prophylactic and therapeutic immunisation with an ErbB-2 (HER2) fusion protein and immunoglobulin V-gene repertoire analysis in a transgenic mouse model of spontaneous breast cancer

ErbB-2 is associated with several solid tumours of which breast cancer is the commonest cancer in women worldwide. Though anti-ErbB-2 antibody appears to play a significant role in prevention and therapy, naturally occurring anti-ErbB-2 antibody associated with the cleaved ectodomain of overexpressed ErbB-2 self antigen is detectable in patients. It is therefore essential to understand the course of antibody mediated protection during disease progression. 100% of FVB/N(neu) mice expressing mutated, constitutively active ErbB-2 develop mammary carcinoma. It has been shown that vaccination with ErbB-2 associated with a T helper cell epitope P30 can offer protection against transplantable tumour but it is unclear whether the same vaccine protects against naturally developing tumour. We have analysed the course of the disease following prophylactic, and therapeutic vaccination in this spontaneous, eutopic mammary carcinoma model that more closely resembles the human disease. 100% protection against tumour development was observed subsequent to prophylactic immunisation but disease progression was unaffected by therapeutic vaccination. The antibody response exhibited restricted expansion of the Immunoglobulin (Ig) variable (V)-gene repertoire by ErbB-2 specific B cells compared with the non-antigen specific B cell pool and control mice. The serum antibody profile was similar in therapeutically injected mice without any effect on tumour burden.

The two sides of HER2/neu: immune escape versus surveillance

The oncogene HER2 is one of the prototypes for targeted immunotherapy of cancer using both monoclonal antibodies as well as T cell based immunotherapies. Effective humoral and cellular immune responses against HER2 can be induced, but these responses can be influenced by the effects of this oncogene on the target tumor cells. The processes involved in HER2-mediated adaptive and innate immunity and the molecular mechanisms underlying the escape of HER2-expressing tumor cells from immune surveillance, particularly from cytotoxic T cells, are discussed. Implementing this knowledge in clinical trials to revert immune evasion may help optimize immunotherapies directed against HER2-expressing tumors.

Interleukin-17 Produced by Malignant Mesothelioma-Polarized Immune Cells Promotes Tumor Growth and Invasiveness

Malignant mesothelioma (MM) is a highly fatal tumor of inner body membranes, the extensive growth of which is supported by both a weak immunogenicity and the ability to reprogram surrounding immune cells towards tumor-supporting phenotypes. Interleukin-17 (IL-17) is a major inflammatory cytokine which is now accepted as the paradigmatic cytokine of many autoimmune diseases; however, its role in tumor immunology has only been partially unraveled, and no data exist regarding its possible involvement in MM. Thus, in this work we evaluated the ability of MM to induce IL-17 production in immune cells and the effects of IL-17 on MM growth and invasiveness. Our data show for the first time that macrophages and CD4+ T-cells are polarized by MM to produce IL-17, and that this cytokine exerts multiple tumor-supporting effects on both cell growth and invasiveness. These data provide novel evidence of the crosstalk occurring between MM and immune cells and suggest potential targets for the development of new pharmacological approaches for MM treatment.

Local radiotherapy increases the level of autoantibodies to ribosomal P0 protein but not to heat shock proteins, extracellular matrix molecules and EGFR/ErbB2 receptors in prostate cancer patients

Prostate cancer is a common cancer among men in developed countries. Although hormonotherapy and radiotherapy (RT) represent valid therapies for prostate cancer treatment, novel immunological approaches have been explored. The development of clinical trials employing cancer vaccines has indicated that immune response to tumor antigens can be boosted and that vaccine administration can improve patient survival. Immune response to tumor antigens could also be enhanced after standard therapies. In the present study, we determined the occurrence of antibodies to extracellular matrix (ECM) molecules, heat shock protein (HSP), ribosomal P0 protein, EGFR, ErbB2 and prostate-specific antigen (PSA) in 35 prostate cancer patients prior to and following local RT and hormonotherapy. We demonstrated that immunity to P0, ECM molecules [collagens (C) CI, CIII, CV, fibronectin (FN) and laminin (LM)] and to HSP90 was associated with malignancy in untreated patients. None of the patient sera showed antibodies to EGFR, while 2 and 1 patients showed reactivity to ErbB2 and PSA, respectively. We also demonstrated that 8 months after therapy the IgG serum levels to CI, CIII, FN and HSP90 significantly decreased. Conversely, the level of P0 autoantibodies increased after therapy in 10 patients. Five of the 10 patients with increased levels of P0 autoantibodies were treated with RT plus hormonotherapy. Treatment of patients did not change the levels of antibodies against EGFR, ErbB2 and PSA. Our results indicated that the modification of antibody level to self molecules after standard treatment of prostate cancer patients is influenced by the type of antigen. Ribosomal P0 protein appears to be a high immunogenic antigen and its immunogenicity increases following RT. In addition, 10 patients with increased levels of autoantibodies to P0 showed PSA mean levels lower than the remaining 25 patients at 18 months. This study may contribute to a better understanding of the immunobiological behavior of prostate cancer patients following standard treatment.

West Nile alternative open reading frame (N-NS4B/WARF4) is produced in infected West Nile Virus (WNV) cells and induces humoral response in WNV infected individuals

Background

West Nile Virus (WNV) is a flavivirus that requires an efficient humoral and cellular host response for the control of neuroinvasive infection. We previously reported the existence of six alternative open reading frame proteins in WNV genome, one of which entitled WARF4 is exclusively restricted to the lineage I of the virus. WARF4 is able to elicit antibodies in WNV infected horses; however, there was no direct experimental proof of the existence of this novel protein. The purpose of this study was to demonstrate the in vitro production of WARF4 protein following WNV infection of cultured VERO cells and its immunity in WNV infected individuals.

Results

We produced a monoclonal antibody against WARF4 protein (MAb 3A12) which detected the novel protein in WNV lineage I-infected, cultured VERO cells while it did not react with WNV lineage II infected cells. MAb 3A12 specificity to WARF4 protein was confirmed by its reactivity to only one peptide among four analyzed that cover the full WARF4 amino acids sequence. In addition, WARF4 protein was expressed in the late phase of WNV lineage I infection. Western blotting and bioinformatics analyses strongly suggest that the protein could be translated by programmed −1 ribosomal frameshifting process. Since WARF4 is embedded in the NS4B gene, we rename this novel protein N-NS4B/WARF4. Furthermore, serological analysis shows that N-NS4B/WARF4 is able to elicit antibodies in WNV infected individuals.

Conclusions

N-NS4B/WARF4 is the second Alternative Reading Frame (ARF) protein that has been demonstrated to be produced following WNV infection and might represent a novel tool for a better characterization of immune response in WNV infected individuals. Further serological as well as functional studies are required to characterize the function of the N-NS4B/WARF4 protein. Since the virus might actually make an extensive use of ARFs, it appears important to investigate the novel six ARF putative proteins of WNV.

Caveolin-1 overexpression is associated with simultaneous abnormal expression of the E-cadherin/α-β catenins complex and multiple ErbB receptors and with lymph nodes metastasis in head and neck squamous cell carcinomas

The presence of lymph node metastases is one of the most important prognostic indicators in head and neck squamous cell carcinomas (HNSCCs). An alteration of the E-cadherin-catenins complex and EGFR is essential for the invasiveness of cancer cells. Caveolin-1, the major structural protein of the caveolae, represents a scaffolding molecule for several signaling proteins including EGFR. Although caveolin-1 has been shown to play a role in inducing the invasive phenotype of cancer cells, its role appears to be cell-type specific and for some tumors it has not been defined yet. In this study we used 57 HNSCC specimens to investigate whether the abnormal expression of caveolin-1 was associated with the derangement of the E-cadherin-catenins complex and with the overexpression of ErbB receptors. We demonstrate that in HNSCCs caveolin-1 overexpression is associated with the simultaneous abnormal expression of at least one member of the E-cadherin/α-β catenins complex and multiple ErbB receptors as well as with lymph node metastases. We also demonstrate that chronic stimulation of a human hypopharyngeal carcinoma cell line (FaDu) with EGF induced the internalization of β-catenin and caveolin-1 and their co-localization with EGFR. Moreover, EGF treatment induced an increased physical interaction between EGFR/β-catenin/caveolin-1 and between E-cadherin/β-catenin/caveolin-1. These molecular events were associated with an increased directional motility of FaDu cells in vitro. These findings may provide new insight into the biology of HNSCC progression and help to identify subgroups of primary HNSCCs with a more aggressive behavior.

[Detecting EGFR autoantibodies in serums of NSCLC patients with peptide array]

背景与目的

自身抗体作为新的肿瘤标志物在肺癌的早期诊断和预后评价中可能发挥重要作用, 本研究利用多肽芯片检测非小细胞肺癌患者血清中表皮生长因子受体（epidermal growth factor receptor, EGFR）的自身抗体, 并筛选自身抗体识别的抗原表位。

方法

使用Intavis公司ASPSL多肽芯片合成仪合成EGFR多肽芯片, 利用多肽芯片检测非小细胞肺癌患者血清中EGFR自身抗体, 并筛选自身抗体识别的抗原表位。结果使用EGFR多肽芯片检测了20例非小细胞肺癌患者,

结果

有6例阳性, 阳性率为30%, 在该6例阳性患者中发现了9个高频位点, 并且有8个高频位点集中在EGFR胞外段的第Ⅲ和第Ⅳ结构域。

结论

本研究为我们进一步研究EGFR和EGFR自身抗体的功能提供了新的线索。

A novel immunotherapy to hepatocellular carcinoma: CD40-activated B lymphocytes transfected with AFPmRNA

Alpha-fetoprotein (AFP) is overexpressed in the majority of hepatocellular carcinomas (HCCs), and thus may offer attractive target for immunotherapy against this neoplasm. CD40 ligand (CD40L) is the major signal that induces B cells to efficiently present antigen to T cells, and CD40-activated B (CD40-B) lymphocyte cells may boost cytotoxic T lymphocytes (CTLs) when they are pulsed with tumour antigens. CTL is considered to be a promising therapeutic means for the treatment of cancers. Here, we intend to build a plasmid pGEM4Z/AFP/A64 and to prepare AFPmRNA, then separate B lymphocyte cells. These CD40-B cells are pulsed with AFPmRNA, and they may boost robust T-cell responses, but more importantly, they also may prime naive T-cell responses against hepatocarcinoma. These CD40-B cells will be a powerful source of APCs generated by simple and reliable technology that may be applied to antigen responses, immune treatment for cancer, vaccination approaches, and ex vivo T-cell expansion for adoptive therapy. AFPmRNA-transfected B cells may represent a broadly applicable vaccine strategy to induce potentially therapeutic CTL responses against AFP-positive target cells in HCC. Vaccine strategies such as these may contribute to the effective future treatment of HCC.

DNA vaccines targeting tumor antigens to B7 molecules on antigen-presenting cells induce protective antitumor immunity and delay onset of HER-2/Neu-driven mammary carcinoma

PURPOSE

Presentation of tumor antigens by professional antigen-presenting cells (APC) is critical for the induction of tumor-specific T-cell responses. To facilitate targeted delivery of tumor antigens to APC, we generated DNA vaccines that encode secreted fusion proteins consisting of the extracellular domain of CTLA-4 for binding to costimulatory B7 molecules on APC, fused to residues 1 to 222 of human ErbB2 (HER-2) or a corresponding 224 residues fragment of its rat homologue Neu.

EXPERIMENTAL DESIGN

Induction of humoral and cellular immune responses and antitumoral activity of the DNA vaccines were tested in murine tumor models with transfected renal carcinoma cells expressing the respective antigens and in transgenic BALB-neuT mice developing spontaneous Neu-driven mammary carcinomas.

RESULTS

Vaccination of BALB/c mice with CTLA-4-ErbB2(222) plasmid DNA markedly improved tumor-free survival on challenge with ErbB2-expressing Renca cells in comparison with untargeted ErbB2(222), accompanied by induction of stronger ErbB2-specific antibody and CTL responses. Likewise, a CTLA-4 vaccine carrying the unrelated NY-ESO-1 cancer-germline antigen was more effective than untargeted NY-ESO-1 in the protection of mice from challenge with NY-ESO-1-expressing tumor cells. Importantly, antitumoral activity of such a CTLA-4 fusion vaccine could be reproduced in immunotolerant BALB-neuT mice, where a corresponding CTLA-4-Neu(224) DNA vaccine markedly delayed the onset of spontaneous Neu-driven mammary carcinomas.

CONCLUSIONS

Our results show that plasmid DNA vaccines for in vivo expression of tumor antigens targeted to APC induce potent immune responses and antitumoral activities, providing a rationale for further development of this approach for specific cancer immunotherapy.

A common repertoire of autoantibodies is shared by cancer and autoimmune disease patients: Inflammation in their induction and impact on tumor growth

The repertoire of autoantibodies found in cancer patients partly overlaps with that typical of patients with autoimmune diseases. Beside the biochemical and immunological properties of the target antigens and their altered expression in tumor tissues, the intratumoral inflammatory context can play a key role in the induction of autoimmune disease-associated autoantibodies in cancer patients. Furthermore, the impact of such antibodies on cancer growth and progression can be deeply influenced by the interplay with inflammation. The characterization of the spontaneous humoral responses occurring in cancer patients, of the mechanisms that trigger and sustain the autoantibody response and of the biological effects of such autoantibodies may help the rational design of anti-cancer immunotherapeutic protocols.

Nuclear translocation of HER-4/c-erbB-4 is significantly correlated with prognosis of esophageal squamous cell carcinoma

BACKGROUND

HER family is an attractive target for the treatment of esophageal cancer. The clinical relevance of HER-4 has not been yet characterized.

METHODS

The expression of HER-4 was immunohistochemically examined in 61 surgically resected esophageal squamous cell carcinomas (ESCC), and the prognostic significance of HER-4 in ESCC was evaluated.

RESULTS

HER-4 was positive in the cytoplasm and cell membrane of 51 (84%) tumors, with variable intensity and a heterogeneous distribution, with preferential expression in well or moderately differentiated tumors. Nuclear staining of HER-4 was observed in 37 (61%) cases as well. The membranous/cytoplasmic, but not nuclear, expression of HER-4 was positively correlated with the expression of HER-2 and HER-3. Survival of the HER-4-positive group was significantly better than that of the HER-4-negative group (P < 0.05). Multivariate analysis revealed that extranuclear expression of HER-4 was independently correlated with increased survival. In contrast, nuclear staining of HER-4 was correlated with increased T stage, which resulted in a significant reduction in survival in the HER-4 positive group (P < 0.05).

CONCLUSION

Extranuclear HER-4 may have negative effects on the progression of ESCC, whereas nuclear translocation of HER-4 may elicit a tumor-promoting property. Immunohistochemical detection of HER-4 localization is clinically useful to predict the survival of the patients with ESCC.

Humoral immune responses in patients vaccinated with 1-146 HER2 protein complexed with cholesteryl pullulan nanogel

The CHP-HER2 vaccine, comprising truncated 146HER2 protein complexed with nanogels of cholesteryl pullulan (CHP), is a novel protein antigen vaccine that elicits 146HER2-specific CD8(+) and CD4(+) T-cell immune responses in patients with HER2-expressing tumors. We analyzed the humoral responses in patients vaccinated with CHP-HER2 and those with CHP-HER2 plus granulocyte-macrophage colony-stimulating factor (GM-CSF). The vaccine was injected subcutaneously at a dose of 300 microg protein. Nine patients received the vaccine alone over the first four injections, followed by CHP-HER2 with GM-CSF or OK-432, whereas six received CHP-HER2 plus GM-CSF from the first cycle. 146HER2-specific IgG antibodies were induced in 14 patients, who were negative at baseline. The antibodies became detectable after the second or third vaccination and reached plateau levels after the third or fourth cycle in patients vaccinated with CHP-HER2 plus GM-CSF. In contrast, the antibodies appeared only after the third to sixth vaccination and the plateau appeared after the fourth to eighth cycle in patients vaccinated with the CHP-HER2 vaccine alone over the first four cycles. The antibodies induced by the vaccine were not reactive with HER2 antigen expressed on the cell surface in any of the patients. Epitope analysis using overlapping peptides revealed a single region in the 146HER2 protein, amino acids 127-146, in eight patients who were initially vaccinated with CHP-HER2 alone. Similarly, the same HER2 region was recognized dominantly in patients vaccinated with GM-CSF. Our results indicate that CHP-HER2 induced HER2-specific humoral responses in patients with HER2-expressing tumors and that GM-CSF seems to accelerate the responses.

A DNA vaccine against chimeric AFP enhanced by HSP70 suppresses growth of hepatocellular carcinoma

Alpha-fetoprotein (AFP) is produced principally in fetal liver, gastrointestinal tract and the yolk sac which is temporarily present during embryonic development. AFP is overexpressed in the majority of hepatocellular carcinoma (HCC) and thus offers an attractive target for immunotherapy against this neoplasm. Here, we report that anti-HCC effects were achieved in a therapeutic setting with a DNA vaccine encoding mouse AFP and co-expressing heat shock protein 70 (HSP70) gene. We also demonstrated that this vaccine elicited a marked and highly effective AFP specific CTL response against AFP-positive target cells. This vaccine also induced the prolongation of life span in mice bearing the tumor and the eradication of HCC. It is anticipated that vaccine strategies such as this may contribute to the effective future treatment of hepatocellular carcinoma.

Immunity to extracellular matrix antigens is associated with ultrastructural alterations of the stroma and stratified epithelium basement membrane in the skin of Hashimotos thyroiditis patients

Employing purified extracellular matrix (ECM) proteins, i.e. type I, III, IV and V collagens (CI, CIII, CIV, CV), laminin (LM) and fibronectin (FN), as antigen sources we detected autoantibodies to conformational and/or denatured ECM antigens among 34 of 50 sera obtained from Hashimotos thyroiditis (HT) patients and 6 of 51 control sera obtained from non-autoimmune thyroid disease patients and healthy donors (HT sera vs. control sera p=4 x 10-9). Reactivity to conformational antigens, mostly due to autoantibodies of the IgG isotype, was observed in 30/50 HT sera and in 6/51 control sera (p=3.5 x 10-7) and was not always concomitant with that to linear antigens, found in 23/50 HT and in 6/51 control sera (p=1.6 x 10-4). Ultrastructural analysis of skin biopsies obtained from 18 HT patients without symptomatic cutaneous diseases revealed defects of the stratified squamous epithelium basement membrane in 11/18, alterations of the stroma in 13/18 and both basement membrane and stromal defects in 9/18. Interestingly, 13/13 (p=0.012) and 9/11 (p=0.012) patients with stromal and basement membrane defects respectively, exhibited serum antibodies to at least one ECM antigen involved in the organization of the altered tissue compartment. Lastly, 10/18 skin biopsies presented immunoglobulin (Ig) and/or complement (C3) deposits along the cutaneous basement membrane zone (BMZ) or in the papillary dermis and 9/10 sera from the same patients simultaneously showed antibodies to at least one ECM antigen involved in the organization of these two skin compartments. Besides, 8/11 HT patients with basement membrane defects exhibited Ig or C3 deposits along the BMZ. Our findings suggest that autoantibodies to ECM molecules might contribute to the development of asymptomatic extra-thyroid skin diseases in HT patients.

Active antimetastatic immunotherapy in Lewis lung carcinoma with self EGFR extracellular domain protein in VSSP adjuvant

The epidermal growth factor receptor (EGFR) plays a central role in regulating neoplastic processes. The EGFR overexpression in many human epithelial tumors has been correlated with disease progression and bad prognosis. Passive EGFR-directed immunotherapy, but not active specific approaches, has already been introduced in medical oncology practice. Then we wonder if mice immunization with the extracellular domain of murine EGFR (mEGFR-ECD) in adjuvants can circumvent tolerance to self EGFR, by inducing an immune response with consequent antitumor effect. The present study demonstrated that despite mEGFR expression in thymus, strong DTH response was induced by inoculation of mice with the mEGFR-ECD. This self-immunization, using both CFA and very small sized proteoliposomes from Neisseria meningitidis (VSSP), promoted highly specific IgG titers, predominantly IgG2a and IgG2b. Sera from mice immunized with mEGFR-ECD/VSSP not only recognized EGFR+ tumor cell lines by FACS, but also inhibited their in vitro growth, even in the absence of complement. Noteworthy, vaccination of mice with mEGFR-ECD/VSSP stimulated a potent antimetastatic effect in the EGFR+ Lewis lung carcinoma model, while reproduction-associated side effects were absent. Curiously, mice immunized with the human EGFR-ECD (Her1-ECD) in VSSP though induced highly specific IgG antibodies with strong in vitro cytotoxic effect over EGFR+ human cell lines, showed low cross-reactivity with the mEGFR-ECD. These results further encouraged the development of the Her1-ECD/VSSP vaccine project for patients with EGFR+ tumors.

A study of the humoral immune response of breast cancer patients to a panel of human tumor antigens identified by phage display

OBJECTIVE

In this article we provide evidence of a significant spontaneous humoral response in cancer patients.

METHODS

A panel of tumor-associated antigens, previously identified through serological screening of phage-displayed cDNA libraries from solid human tumors, breast carcinoma cell lines and human testis by employing breast cancer patient sera, was used in this study to survey sera from 182 patients with known disease histories and clinical stages.

RESULTS

This analysis reveals a statistically significant association between tumor disease and presence in peripheral blood of IgG antibodies against four autoantigens. One of these antigens (D7-1) is particularly interesting in that the antibody response against it grows with cancer progression from stages I through IV, with an incidence of 13.2, 13.5, 18.2 and 27%, respectively. The significance of this stage-dependent increase in the incidence is confirmed by the Mantel-Haenszel Chi-squared test (P=0.001).

CONCLUSIONS

Our data confirm association between breast cancer diagnosis of patients and presence in their peripheral blood of antibodies against several autoantigens identified by phage display.

ErbB4 increases the proliferation potential of human lung cancer cells and its blockage can be used as a target for anti-cancer therapy

Clinical and experimental data suggest that ErbB-4, a member of the epidermal growth factor receptor family, may have a role in cancer progression and response to treatment. We found recently, using a retrospective clinical analysis, that expression of ErbB-4 receptor is correlated with metastatic potential and patient survival in non-small-cell lung cancer (NSCLC). The purpose of this work was to correlate the expression of the ErbB-4 and lung cancer cells growth in vitro and in vivo and to determine the therapeutic potential of a monoclonal antibody to ErbB-4 against lung cancer. For this aim, we ectopically expressed ErbB-4 in a human NSCLC cell line that did not express the ErbB-4 protein. Overexpression of ErbB-4 produced a constitutively activated ErbB-4 receptor. The transfected ErbB-4 positive clones showed an increased cell proliferation in vitro and in vivo in comparison with parental ErbB-4 negative cells and with the cells transfected by neomycin-resistant gene. A monoclonal antibody to ErbB-4 showed both an inhibitory effect on growth rate and an increasing apoptotic rate in the cells expressing ErbB-4. The results of the current study provide evidence that ErbB-4 plays a significant role in human lung cancer and may serve as a molecular target for anticancer therapy.

Laminin alpha2 chain-positive vessels and epidermal growth factor in lung neuroendocrine carcinoma: a model of a novel cooperative role of laminin-2 and epidermal growth factor in vessel neoplastic invasion and metastasis

Capillaries expressing the laminin alpha2 chain in basement membranes may be considered early developing vessels in normal and neoplastic human tissues. Therefore, we investigated whether up-regulation of this extracellular matrix protein favors transendothelial migration of neoplastic cells and then metastasis. In lung small and large cell neuroendocrine carcinomas, which exhibit a stronger metastatic tendency among carcinomas, laminin alpha2 chain-positive vessels were more numerous than in carcinoid tumors and supraglottis, breast, and lung non-small cell carcinomas, suggesting a direct relationship between these vessels and metastasis. In vitro studies showed that epidermal growth factor (EGF) induced a more efficient migration of the AE-2 lung neuroendocrine carcinoma cell line through the purified laminin alpha2 chain rather than through the laminin beta1 chain and fibronectin. AE-2 cells constitutively expressed all EGF receptors and the alpha6beta1 integrin, which is one of the laminin alpha2 chain receptors. EGF up-regulated alpha6beta1 expression in several tumors. In this regard, we show that EGF increased the chemo-kinetic migration of AE-2 cells through EAHY endothelial monolayers, which was inhibited by the anti-alpha6 integrin chain monoclonal antibody. These data indicate that laminin alpha2 chain and alpha6beta1 may be mutually involved in EGF-dependent migration of AE-2 cells and that laminin alpha2 chain-positive vessels may favor metastasis of EGF-dependent tumors.

Vaccination with cetuximab mimotopes and biological properties of induced anti-epidermal growth factor receptor antibodies

BACKGROUND

The monoclonal antibody cetuximab (IMC-225, Erbitux) inhibits epidermal growth factor receptor (EGFR) signaling and has been approved for metastatic colon cancer therapy. However, to achieve effective titers, passive antibody therapies must be repeatedly administered over long periods. To overcome this limitation, we aimed to generate a vaccine inducing continuously available "cetuximab-like" antibodies in vivo using the mimotope approach.

METHODS

We used the phage display technique to identify four peptides structurally mimicking the cetuximab epitope. We coupled two of these peptides to an immunogenic carrier protein, and we vaccinated four groups (n = 8) of BALB/c mice intraperitoneally with 10 microg of the mimotope conjugates, a control peptide conjugate, or the carrier protein alone. We assessed antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity mediated by the induced antibodies against EGFR-overexpressing human A431 carcinoma cells. We then tested receptor internalization capacity of the induced antibodies with fluorescently labeled EGFR, and we assayed their growth inhibitory potential toward A431 cells with a [3H]thymidine proliferation assay.

RESULTS

Mimotope-induced antibodies recognized EGFR, and both types of antibody-mediated cytotoxic effects were elicited by these antibodies. In both cellular cytotoxicity assays, the mimotope-induced antibodies exhibited specific lysis of more than 50%. The induced antibodies caused internalization of the receptor from the cell surface into endocytic vesicles and inhibited growth of EGFR-expressing cells to a similar extent as cetuximab [67% (95% confidence interval {CI} = 55% to 79%) and 69% (95% CI = 55% to 84%), respectively].

CONCLUSIONS

Epitope-specific immunization is feasible for active anti-EGFR immunotherapy. The in vitro biologic features of mimotope-induced antibodies are similar to those of the monoclonal antibody cetuximab.

Endogenous Anti-HER2 Antibodies Block HER2 Phosphorylation and Signaling through Extracellular Signal-Regulated Kinase

Immunologic targeting of the oncoprotein HER2/neu with monoclonal antibodies is an important component of current therapeutic strategies for patients with locally and systemically advanced breast cancer. Engineered antibodies targeting HER2 may have agonist or antagonist effects on HER2, but little is known about whether endogenous antibodies modulate HER2 activity. Vaccination of patients with HER2 peptides successfully induced antibodies in a minority of patients with HER2-expressing malignancy. A subset of antibodies specifically suppressed phosphorylation of HER2 on tyrosine Y1248, a residue critical for HER2 signaling through extracellular signal-regulated kinase. These antibodies also suppressed extracellular signal-regulated kinase phosphorylation and inhibited colony formation in soft agar. The majority of the antibodies that suppressed HER2 phosphorylation displayed specificity for amino acids 328 to 345 and 369 to 384. The isotype of anti-HER2 antibodies was predominantly IgG3 of low avidity, suggesting a Th1 response to peptide vaccine. Endogenous anti-HER2 antibodies can effectively suppress HER2 kinase activity and downstream signaling to inhibit the transformed phenotype of HER2-expressing tumor cells.

Mechanisms of resistance to Erbitux (anti-epidermal growth factor receptor) combination therapy in pancreatic adenocarcinoma cells

We previously demonstrated that pancreatic adenocarcinoma BxPC-3 xenografts display resistance to treatment with Erbitux, gemcitabine, and radiation, whereas MIA PaCa-2 xenografts are highly sensitive to the same therapy. Here, we elucidate in vitro mechanisms that may explain the observed differential response of epidermal growth factor receptor (EGFR) expressing pancreatic adenocarcinoma xenografts to Erbitux-based combination therapy in vivo. MIA PaCa-2 and BxPC-3 protein lysates were probed with antibodies to EGFR, ErbB2, ErbB3, and ErbB4. Constitutive ErbB3 activity was visualized by immunoblot analysis using anti-phosphotyrosine antibodies and receptor-specific immunoprecipitates. erbB2 and erbB3 gene expression in both cell lines was quantified with real-time polymerase chain reaction. Erbitux-induced internalization of EGFR was determined by flow cytometry following Erbitux treatment for different incubation times at 0 degrees C and 37 degrees C. MIA PaCa-2 and BxPC-3 protein extracts were also probed with anti-phospho-mitogen-activated protein kinase antibody after stimulation with EGF and in the presence of Erbitux. Although both cell lines expressed EGFR and ErbB2 protein, ErbB3 protein was selectively expressed by BxPC-3 cells, where it also showed evidence of constitutive phosphorylation. There was a 10-fold increase of erbB3 transcript levels in BxPC-3 cells compared with MIA PaCa-2. ErbB4 protein was not detectable in either cell line. Erbitux mediated EGFR internalization in MIA PaCa-2 cells after 2 hours of incubation, whereas it did not promote EGFR internalization in BxPC-3 cells. Likewise, EGF-dependent phosphorylation of MAPK p44/42 was blocked by Erbitux treatment in MIA PaCa-2 but not BxPC-3 cells. Erbitux selectively interfered with EGF-induced MAPK activation in MIA PaCa-2 but not BxPC-3 cells. Persistent MAPK activation and impaired in vitro internalization of EGFR by BxPC-3 pancreatic cancer cells may be due to constitutive ErbB3 signaling, facilitated by heterodimerization with EGFR, which may explain resistance to Erbitux-based combination therapy in vivo.

Frequent overexpression of multiple ErbB receptors by head and neck squamous cell carcinoma contrasts with rare antibody immunity in patients

In an effort to elucidate the role of ErbB receptors in human head and neck squamous cell carcinoma (HNSCC), expression abnormalities and subcellular localization of epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4 were investigated along with EGF and tenascin by immunohistochemistry in 38 carcinomas as compared to adjacent normal mucosa of 24 cases. Although tumour-specific overexpression affected each ErbB receptor (EGFR 47%, ErbB2 29%, ErbB3 21%, ErbB4 26%), EGFR abnormalities were most prevalent. The latter, and overexpression of more than two ErbB receptors in the same tumour, which always included EGFR, correlated with metastatic disease. ErbB products were specifically detected on the cell membrane and in the cytoplasm. In contrast, ErbB4 was uniquely localized to the nucleus in 7 carcinomas and a tumour-derived cell line, indicating a role for regulated intramembrane proteolysis resulting in nuclear ErbB4 translocation in HNSCC. Expression of prototype ligand EGF or low-affinity stromal activator tenascin correlated significantly with EGFR overexpression, implying chronic EGFR activation. Simultaneous overexpression of additional ErbB receptors in most of these cases suggested recurrent involvement of receptor heterodimers. In spite of frequent ErbB receptor alterations, autologous ErbB serum antibodies were rare, with only 1 of 38 tumour patients exhibiting an ErbB2-specific immune response. Based on upregulation of several known immunosuppressive molecules, scarcity of ErbB-specific antibodies is consistent with attenuation of natural tumour-specific immune responses in HNSCC.

Identification of epidermal growth factor receptor-derived peptides immunogenic for HLA-A2(+) cancer patients

Epidermal growth factor receptor (EGFR) is one of the most appropriate target molecules for cancer therapy because of its relatively high expression in about one-third of all epithelial cancers in correlation with neoplasmic progression. With respect to EGFR-targeted therapies, antibodies and tyrosine-kinase inhibitors have been intensively studied, a novel EGFR-tyrosine-kinase inhibitor ZD1839 has been approved as an anticancer drug, and many other agents are now under clinical trial. In addition, cytotoxic T lymphocyte (CTL)-directed epitope peptides could be another class of compounds useful in EGFR-targeted therapies. However, there is presently no information on CTL-directed peptides of EGFR. Therefore, from the viewpoint of development of peptide-based cancer therapy, this study was intended to determine the EGFR-derived peptides recognised by both cellular and humoral immunities in HLA-A2(+) epithelial cancer patients. We herein report finding of two such types of EGFR-derived peptides at position 479-488 and 1138-1147, both of which were recognised by the majority of patients' sera (IgG), and also possessed the ability to induce HLA-A2-restricted peptide-specific CTLs against EGFR-positive tumour cells in peripheral blood mononuclear cells (PBMCs) of epithelial cancer patients. These results may provide a scientific basis for the development of EGFR-based immunotherapy for HLA-A2(+) cancer patients.

Intratumoral administration of an adenovirus expressing a kinase dead form of ErbB-2 inhibits tumor growth

ErbB-2 is amplified or overexpressed in a number of different cancers including breast, ovarian, lung, prostate and stomach. This overexpression leads to enhanced receptor dimer formation and stabilization allowing the receptor to remain in an active state. The clinical consequences of ErbB-2 overexpression include increased tumor aggressiveness, poor prognosis, decreased patient survival and resistance to chemotherapy. As a result, a variety of different strategies are being examined to inhibit its function or expression. In this study, we explored the efficacy of a type 5 recombinant adenovirus encoding a kinase dead form of ErbB-2, AderbB-2 Delta tk, as a potential therapeutic agent for breast cancer using a murine breast model expressing constitutively active ErbB-2. Co-expression in tumor cells of the kinase dead form of ErbB-2 inhibits receptor activity and induces the death of cells expressing constitutively active ErbB-2. In addition, AderbB-2 Delta tk exhibits antitumor activity in both immune-competent and immune-deficient animals with increased antitumor activity in the immune-competent animals. The results suggest both immune and non-immune mechanisms contribute to the antitumor efficacy of this vector.

Immunochemical studies of antigenic lymphoma-associated proteins

We have previously reported that plasma from patients with anaplastic lymphoma kinase (ALK)-positive lymphoma contains antibodies against the oncogenic kinase NPM-ALK protein characteristic of this disease. We investigated whether this reactivity represents a phenomenon unique to ALK-positive lymphoma by screening plasma from patients with follicular lymphoma for antibodies to BCL-2 protein. Eight out of 10 samples showed such reactivity (and in six cases gave specific staining of BCL-2-transfected cells). As these findings suggest a new biochemical approach to the identification of oncogenic proteins in lymphoma, we investigated whether antibodies present in patients with ALK-positive lymphoma can precipitate NPM-ALK in quantities which should be sufficient for further analysis. We found that plasma samples from all10 patients studied immunoprecipitated NPM-ALK asaprotein visible in silver-stained sodium dodecyl sulphatepolyacrylamide gels. Finally we demonstrated that NPM-ALK could be visualized more clearly if it were immunoprecipitated from extracts of cells in which newly synthesized proteins had been labelled with 35S and then identified by autoradiography. These results suggest a strategy for using patients' autoantibodies to screen for antibodies to other tumour-associated proteins.

Co-localization of multiple ErbB receptors in stratified epithelium of oral squamous cell carcinoma

The expression of all four ErbB receptors was compared by immunohistochemistry, using receptor-specific polyclonal antisera, in 32 invasive, 11 in situ carcinomas, six benign lesions, and 22 samples of histologically normal mucosa adjacent to specimens of carcinoma originating from oral cavity epithelium. Among invasive and in situ carcinoma, EGFR expression was the most prevalent (in 29/32 and 8/11 cases, respectively) followed by ErbB2 (17/32 and 2/11) and ErbB4 (9/32 and 1/10), while ErbB3 was only detected in invasive tumours (12/32). Specific patterns included invasive tumours with expression of EGFR (8/32) or ErbB4 (1/32) alone, as well as different receptor combinations (EGFR+ErbB2, EGFR+ErbB4, EGFR+ErbB2+ErbB3, EGFR+ErbB2+ErbB4, and all four receptors). Simultaneous expression of three or four ErbB receptors correlated with tumour invasion (p=2.2x10(-4)) and localized in the intermediate epithelial cell layer of well and moderately differentiated tumours. No other significant correlation with clinico-pathological features was noticed. Some benign lesions and histologically normal mucosa adjacent to carcinomas showed weak immunostaining of EGFR (10/28), ErbB2 (4/28) or ErbB4 (3/28). By comparison, overexpression, as indicated by increased staining intensity, was observed in invasive tumours for EGFR (18/32), ErbB2 (8/32), ErbB4 (3/32), and ErbB3 (3/32). Statistical evaluation demonstrated a significant association of EGFR or ErbB2 overexpression with invasive carcinoma when compared with benign lesions and apparently normal epithelium (p=5.2x10(-7) and p=5x10(-3), respectively). Tumour-specific overexpression of ErbB receptors and their co-expression, most frequently involving EGFR and ErbB2, in the same cell layer of neoplastic epithelium, implicate receptor heterodimers in the pathogenesis of oral squamous carcinoma.

Overexpression of HER-2/neu enhances the sensitivity of human bladder cancer cells to urinary isoflavones

Soybean foods have been suggested to be practical chemopreventives for human urinary tract cancers. Recently, we demonstrated that the co-operative action of isoflavones results in an increased dose-dependent growth inhibition and apoptosis than any single isoflavone compound. This study aimed to examine the potential of HER-2/neu as a biological target for soy isoflavones. The sensitivity of the bladder cancer cell lines (n=7) to the isoflavones was inversely related to the amount of HER-2/neu expressed. By using HER-2/neu transfection experiments, all three stable transfectants showed a significant growth inhibition by the isoflavone mixture at concentrations attainable in normal adult urine. An increased inhibition of tyrosine phosphorylation of proteins immunoprecipitated by HER-2/Neu was observed in the neu-transfectants compared with controls. The results of this study suggest that HER-2/neu may be a practical biochemical target for urinary isoflavones in vivo.

Targeting growth factor receptors: integration of novel therapeutics in the management of head and neck cancer

Tyrosine kinase (type 1) growth factor receptors include the erbB family. These cell surface receptors were discovered in the context of cellular transformation and have subsequently been found to be overexpressed in many types of human cancer. Cumulative evidence suggests that upregulation of the most well-characterized receptor, erbB1, also known as the epidermal growth factor receptor, plays a significant role in the development and progression of head and neck squamous cell carcinoma. A variety of strategies have been developed that specifically target epidermal growth factor receptor, including monoclonal antibodies, ligand-linked immunotoxins, tyrosine kinase inhibitors, and antisense approaches. Epidermal growth factor receptor blockade in head and neck squamous cell carcinoma cell lines and preclinical animal models inhibits cell proliferation and tumor growth. Clinical trials are under way to test the safety and efficacy of many of these targeting strategies in head and neck squamous cell carcinoma patients. Encouraging preliminary results combining an epidermal growth factor receptor targeting approaches with chemotherapy or radiotherapy suggest that interference with this growth factor receptor may enhance antitumor efficacy of standard therapies. As erbB family member interactions and downstream signaling pathways are elucidated in head and neck squamous cell carcinoma, specific targeting strategies may become incorporated into standard treatment approaches.

Identification of epitope regions recognized by tumor inhibitory and stimulatory anti-ErbB-2 monoclonal antibodies: implications for vaccine design

The self-oncoprotein ErbB-2 is overexpressed in a number of malignancies. The presence of endogenous anti-ErbB-2 Ab and T cell immune responses to this protein in cancer patients has made ErbB-2 an attractive target for active immunization. However, the finding that murine anti-ErbB-2 Abs can have stimulatory, inhibitory, or no effects on cancer cell growth suggests that an inappropriately induced immune response may have an adverse effect. To ensure the induction of a beneficial Ab response, it is important to identify the epitopes recognized by these Abs. In this study we have used phage-displayed ErbB-2 gene fragment libraries and synthetic peptides to epitope-map a panel of anti-ErbB-2 mAbs. The epitopes of three mAbs, N12, N28, and L87, were successfully located to C531-A586, T216-C235, and C220-C235 of ErbB-2, respectively. It was found that while N12 inhibited tumor cell proliferation, N28 stimulated the proliferation of a subset of breast cancer cell lines overexpressing ErbB-2. The peptide region recognized by N12, (C531-A586; EP531), was used as an immunogen to selectively induce an inhibitory immune response in mice. Mice immunized with the GST fusion peptide (GST-EP531) recognized the peptide region EP531 as well as native ErbB-2. More importantly, Igs purified from mouse sera were able to inhibit up to 85% of tumor cell proliferation. In conclusion, our study provides direct evidence of the function-epitope relationship of anti-ErbB-2 Abs and also emphasizes the value of inducing a potent tumor inhibitory polyclonal Ab response by rationally selecting regions of ErbB-2 used for immunization.

Induction of ErbB-2/neu-specific protective and therapeutic antitumor immunity using genetically modified dendritic cells: enhanced efficacy by cotransduction of gene encoding IL-12

Overexpression of ErbB-2/neu occurs in 20-30% of patients with breast cancer and indicates a poor prognosis. The presence of a detectable immune response to ErbB-2/neu in some patients suggests that this oncogene may be a useful target for vaccine therapy. We evaluated whether genetic immunization using dendritic cells (DC) transduced ex vivo with an adenovirus expressing the ErbB-2/neu gene (AdNeuTK) could induce protective and therapeutic immunity against a breast tumor cell line overexpressing ErbB-2/neu. Subcutaneous (s.c.) immunization with the DC vaccine elicited protective immunity in an average of 60% of animals. CTL analysis demonstrated specific cytotoxic activity against breast tumor cells, as well as syngeneic fibroblasts transduced with AdNeuTK. In vivo depletion studies demonstrated both CD4+ and CD8+ T cells were required. In a therapeutic setting, immunization with the DC vaccines could cure mice with pre-established tumors and efficacy was further enhanced by cotransducing DCs with a vector expressing murine IL-12 (AdmIL-12). These studies support DC vaccines as a therapeutic strategy for human breast cancer, while emphasizing the importance of optimizing an immune response by combining tumor antigen presentation with immunostimulatory cytokines.

DNA vaccination against rat her-2/Neu p185 more effectively inhibits carcinogenesis than transplantable carcinomas in transgenic BALB/c mice

The ability of vaccination with plasmids coding for the extracellular and the transmembrane domain of the product of transforming rat Her-2/neu oncogene (r-p185) to protect against r-p185(+) transplantable carcinoma (TUBO) cells and mammary carcinogenesis was evaluated. In normal BALB/c mice, DNA vaccination elicits anti-r-p185 Ab, but only a marginal CTL reactivity, and protects against a TUBO cell challenge. Massive reactive infiltration is associated with TUBO cell rejection. In BALB/c mice transgenic for the rat Her-2/neu gene (BALB-neuT), DNA vaccination elicits a lower anti-r-p185 Ab response, no CTL activity and only incompletely protects against TUBO cells, but markedly hampers the progression of carcinogenesis. At 33 wk of age, when control BALB-neuT mice display palpable tumors in all mammary glands, about 60% of immunized mice are tumor free, and tumor multiplicity is markedly reduced. Tumor-free mammary glands still display the atypical hyperplasia of the early stages of carcinogenesis, and a marked down-modulation of r-p185, along with a massive reactive infiltrate. However, BALB-neuT mice protected against mammary carcinogenesis fail to efficiently reject a TUBO cell challenge. This suggests that the mechanisms required for the rejection of transplantable tumors may not coincide with those that inhibit the slow progression of carcinogenesis.

Immune response to the ALK oncogenic tyrosine kinase in patients with anaplastic large-cell lymphoma

Oncogenic anaplastic lymphoma kinase (ALK) fusion proteins (nucleophosmin–ALK [NPM-ALK] and other variants) are expressed in many cases of anaplastic large-cell lymphoma (ALCL) but are absent from normal tissues. The possibility that ALK proteins are immunogenic was investigated with the use of an immunocytochemical technique to screen plasma from ALK-positive ALCL on transfectants expressing ALK proteins and by an in vitro kinase assay. Circulating antibodies against NPM-ALK protein were present in all ALK-positive ALCL patients (11 out of 11 cases) studied while 10 patients also had antibodies recognizing normal ALK protein. Weak antibodies reactive with NPM-ALK (which may represent anti-NPM autoantibodies) were detected by the in vitro kinase assay in 3 of the 10 control samples (but not by immunocytochemistry). The presence of anti-ALK antibodies may be relevant to the relatively good prognosis of ALK-positive ALCL. The immunocytochemical technique for detecting anti-ALK activity is simple and semiquantative and may provide a means of detecting B-cell responses to other tumor-associated molecules.

Immune response to the ALK oncogenic tyrosine kinase in patients with anaplastic large-cell lymphoma

Oncogenic anaplastic lymphoma kinase (ALK) fusion proteins (nucleophosmin–ALK [NPM-ALK] and other variants) are expressed in many cases of anaplastic large-cell lymphoma (ALCL) but are absent from normal tissues. The possibility that ALK proteins are immunogenic was investigated with the use of an immunocytochemical technique to screen plasma from ALK-positive ALCL on transfectants expressing ALK proteins and by an in vitro kinase assay. Circulating antibodies against NPM-ALK protein were present in all ALK-positive ALCL patients (11 out of 11 cases) studied while 10 patients also had antibodies recognizing normal ALK protein. Weak antibodies reactive with NPM-ALK (which may represent anti-NPM autoantibodies) were detected by the in vitro kinase assay in 3 of the 10 control samples (but not by immunocytochemistry). The presence of anti-ALK antibodies may be relevant to the relatively good prognosis of ALK-positive ALCL. The immunocytochemical technique for detecting anti-ALK activity is simple and semiquantative and may provide a means of detecting B-cell responses to other tumor-associated molecules.

ErbB2 immune response in breast cancer patients with soluble receptor ectodomain

Investigation of ErbB2 immunity in human breast cancer employing recombinant expression sources in immunoblot analysis revealed ErbB2-specific antibodies of the IgG isotype in sera of 14 of 71 cancer patients and 1 of 31 normal donors. Reactivity was confirmed on ErbB2-specific immunoprecipitates. Independent evidence of existing ErbB2 immunity was obtained after in vitro transformation of peripheral blood leukocytes from six positive patients. Furthermore, in vitro immortalization of B-lymphocytes unmasked existent ErbB2 immunity in 1 of 8 patients negative for ErbB2 serum antibodies. Determining shed ErbB2 extracellular domain as an indirect measure of tumor burden in ErbB2-positive malignancy, elevated serum levels were observed in 16 of 71 breast cancer and 1 of 31 normal donor sera. Strikingly, existing ErbB2 immunity correlated significantly with elevated shed ErbB2 ectodomain among the patients analyzed. Incidence of both ErbB2 immunity and elevated ErbB2 extracellular domain increased with a progressed disease stage and was significantly associated with metastatic breast cancer. These observations implicate soluble ErbB2 amounts in vivo in the development of ErbB2 immunity in breast cancer. They further project serum analysis of ErbB2 immunity and soluble ectodomain as potential markers of disease progression in ErbB2-positive malignancy.