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

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.

Proteasome inhibition by bortezomib parallels a reduction in head and neck cancer cells growth, and an increase in tumor-infiltrating immune cells

Head and neck cancer (HNC) has frequently an aggressive course for the development of resistance to standard chemotherapy. Thus, the use of innovative therapeutic drugs is being assessed. Bortezomib is a proteasome inhibitor with anticancer effects. In vitro antitumoral activity of Bortezomib was investigated employing human tongue (SCC-15, CAL-27), pharynx (FaDu), salivary gland (A-253) cancer cell lines and a murine cell line (SALTO-5) originated from a salivary gland adenocarcinoma arising in BALB-neuT male mice transgenic for the oncogene neu. Bortezomib inhibited cell proliferation, triggered apoptosis, modulated the expression and activation of pro-survival signaling transduction pathways proteins activated by ErbB receptors and inhibited proteasome activity in vitro. Intraperitoneal administration of Bortezomib delayed tumor growth of SALTO-5 cells transplanted in BALB-neuT mice, protracted mice survival and adjusted tumor microenvironment by increasing tumor-infiltrating immune cells (CD4⁺ and CD8⁺ T cells, B lymphocytes, macrophages, and Natural Killer cells) and by decreasing vessels density. In addition, Bortezomib modified the expression of proteasome structural subunits in transplanted SALTO-5 cells. Our findings further support the use of Bortezomib for the treatment of HNC and reveal its ineffectiveness in counteracting the activation of deregulated specific signaling pathways in HNC cell lines when resistance to proteasome inhibition is developed.

Prognostic and clinical implications of c-erbB-2 expression in patients with oral cancer: A meta-analysis

BACKGROUND

Recently, many studies have suggested that the aberrant expression of c-erbB-2 existed in oral cancer (OC) patients and had a correlation with poor clinical features across OC patients. Considering the inconsistent results among published articles, we performed the meta-analysis to assess the prognostic and clinical effect of c-erbB-2 expression on oral tumors.

METHODS

Web of Science, Embase, and PubMed were retrieved to acquire relevant publications based on selection criteria, up to February 8, 2020. Pooled odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) were applied to evaluate the associations between c-erbB-2 expression and overall survival (OS), disease specific survival, disease-free survival as well as clinicopathology of OC.

RESULTS

A total of 30 literatures with 1499 patients for survival of OC were enrolled in this meta-analysis. The results indicated that c-erbB-2 overexpression was significantly associated with poor OS (HR = 2.40, 95% CI = 1.53-2.55, P < .05), disease specific survival (HR = 2.60, 95% CI = 1.11-4.10, P < .05) and disease-free survival (HR = 2.22, 95% CI = 1.46-2.99, P < .05). Subgroup analysis based on race showed that the significant prognostic value of c-erbB-2 in OC was found both in Caucasians and Asians (OS of Caucasians, HR = 2.90, 95% CI = 1.50-4.31, P < .05; OS of Asians, HR = 1.90, 95% CI = 1.27-2.53, P < .05). Moreover, OC patients with enhanced c-erbB-2 expression were prone to male (OR = 1.97, 95% CI = 1.22-3.19, P < .05), advanced TNM stage (OR = 1.84, 95% CI = 1.17-2.88, P < .05), lymph node metastasis (OR = 2.23, 95% CI = 1.47-3.36, P < .05) and advanced grade (OR = 1.98, 95% CI = 1.30-3.01, P < .05), but not associated with distant metastasis (OR = 1.65, 95% CI = 0.98-3.04, P > .05).

CONCLUSIONS

c-erbB-2 may be a potential indicator in the prediction of prognosis and clinicopathological features in OC patients.

Expression of HER-2/neu in Oral Squamous Cell Carcinoma

BACKGROUND

HER-2/neu is a member of the human epidermal growth factor (HER) family of transmembrane tyrosine kinases, which is significantly associated with the pathogenesis of various cancer types. The aim was to evaluate the expression of HER-2/neu in oral squamous cell carcinoma (OSCC) as a potential biomarker to target antigens for specific immunotherapy in OSCC.

METHODS

One hundred and forty histologically diagnosed OSCC cases were identified. Four to five-micrometer thick formalin-fixed, paraffin-embedded tumor sections were stained with Haematoxylin and Eosin (H and E). Histological grade was assessed according to WHO/Broders classification, while tumors were staged according to the American Joint Committee on Cancer (AJCC) TNM classification from stage I to IV. Immunohistochemistry was performed by using Rabbit monoclonal antibody against HER-2/neu (EP700Y, cell marquee and diluted 1:50). FISH was performed on positive cases using Vysis PathVysion HER-2 DNA probe (Abbott USA). Probes consist of LSI HER gene spectrum orange and control probe CEP 17 spectrum green.

RESULTS

In this study, males were mostly effected (64.3%) with buccal mucosa (49%) to be the commonly involved site for OSCC. Majority of cases were moderately differentiated (62.1%) and 50.7% tumors were Stage IV. HER-2/neu was found to be positive (2+) in one case of OSCC, however weak to moderate complete membrane staining was observed in >10% of the tumor cells. One hundred and thirty nine cases were HER-2/neu negative. FISH analysis of HER-2/neu positive cases also showed gene amplification (Her2-neu/ CEp 17 = 225/33 = 7.2).

CONCLUSIONS

The study showed disparity in the expression of HER-2/neu in OSCC, which is due to multiple reasons. Therefore therapy against HER-2/neu in OSCC is debatable.

(±)-Gossypol induces apoptosis and autophagy in head and neck carcinoma cell lines and inhibits the growth of transplanted salivary gland cancer cells in BALB/c mice

Racemic Gossypol [(±)-GOS], composed of both (-)-GOS and (+)-GOS, is a small BH3-mimetic polyphenol derived from cotton seeds. (±)-GOS has been employed and well tolerated by cancer patients. Head and neck carcinoma (HNC) represents one of the most fatal cancers worldwide, and a significant proportion of HNC expresses high levels of antiapoptotic Bcl-2 proteins. In this study, we demonstrate that (±)-GOS inhibits cell proliferation and induces apoptosis and autophagy of human pharynx, tongue, and salivary gland cancer cell lines and of mouse salivary gland cancer cells (SALTO). (±)-GOS was able to: (a) decrease the ErbB2 protein expression; (b) inhibit the phosphorylation of ERK1/2 and AKT; (c) stimulate p38 and JNK1/2 protein phosphorylation. (±)-GOS administration was safe in BALB/c mice and it reduced the growth of transplanted SALTO cells in vivo and prolonged mice median survival. Our results suggest the potential role of (±)-GOS as an antitumor agent in HNC patients.

HER3 Targeting Sensitizes HNSCC to Cetuximab by Reducing HER3 Activity and HER2/HER3 Dimerization: Evidence from Cell Line and Patient-Derived Xenograft Models

PURPOSE

Our previous work suggested that HER3 inhibition sensitizes head and neck squamous cell carcinoma (HNSCC) to EGFR inhibition with cetuximab. This study aimed to define the role of HER3 in cetuximab resistance and the antitumor mechanisms of EGFR/HER3 dual targeting in HNSCC.

EXPERIMENTAL DESIGN

We treated cetuximab-resistant HNSCC UMSCC1-C and parental UMSCC1-P cell lines with anti-EGFR antibody cetuximab, anti-HER3 antibody MM-121, and their combination. We assessed activities of HER2, HER3, and downstream signaling pathways by Western blotting and cell growth by sulforhodamine B (SRB) and colony formation assays. HER3-specific shRNA was used to confirm the role of HER3 in cetuximab response. The combined efficacy and alterations in biomarkers were evaluated in UMSCC1-C xenograft and patient-derived xenograft (PDX) models.

RESULTS

Cetuximab treatment induced HER3 activation and HER2/HER3 dimerization in HNSCC cell lines. Combined treatment with cetuximab and MM-121 blocked EGFR and HER3 activities and inhibited the PI3K/AKT and ERK signaling pathways and HNSCC cell growth more effectively than each antibody alone. HER3 knockdown reduced HER2 activation and resensitized cells to cetuximab. Cetuximab-resistant xenografts and PDX models revealed greater efficacy of dual EGFR and HER3 inhibition compared with single antibodies. In PDX tissue samples, cetuximab induced HER3 expression and MM-121 reduced AKT activity.

CONCLUSIONS

Clinically relevant PDX models demonstrate that dual targeting of EGFR and HER3 is superior to EGFR targeting alone in HNSCC. Our study illustrates the upregulation of HER3 by cetuximab as one mechanism underlying resistance to EGFR inhibition in HNSCC, supporting further clinical investigations using multiple targeting strategies in patients who have failed cetuximab-based therapy. Clin Cancer Res; 23(3); 677-86. ©2016 AACR.

Human epidermal growth factor receptor 3 in head and neck squamous cell carcinomas

Human epidermal growth factor receptor 3 (HER3) is a member of the human epidermal growth factor receptor (HER) family. The main characteristic of HER3 is that it does not possess tyrosine kinase activity, unlike other HERs. The role of HER3 in tumorigenesis has now been recognized, particularly in head and neck squamous cell carcinomas (HNSCCs). Despite conflicting studies, HER3 was found to be overexpressed in HNSCC samples, and correlates with disease progression and poor survival, especially when it is coexpressed with other HERs. HER3 is a significant factor in HNSCC treatment resistance. Indeed, HER3 is a major mechanism described for cetuximab resistance because of modification of epidermal growth factor receptor (EGFR) internalization and by phosphotidylinositol-3-kinase (PI3K)/AKT signaling pathway activation. HER3 also affects resistance to tyrosine kinase inhibitors (TKIs) and thereby promotes treatment escape and radiotherapy resistance by activation of the survival signaling pathway. To counteract this, pharmacologic inhibitors of HER3 are currently in development and could significantly improve HNSCC treatment. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2412-E2418, 2016.

Immunohistochemical Assessment of HER3 Expression in Odontogenic Cysts

Background:

It has been demonstrated that HER3 plays an important role in some human cancers and the HER3 expression is associated with worse survival in solid tumors.

Objectives:

This study was conducted to compare HER3 expression in epithelial lining of radicular cysts (RCs), dentigerous cysts (DCs) and odontogenic keratocysts (OKCs).

Materials and Methods:

This was a descriptive-analytical study, which assessed all 57 paraffin blocks of RCs, DCs and OKCs (21 RCs, 16 DCs, 20 OKC) from pathological archive of Dentistry College of Zahedan, Iran. The HER3 expression in cytoplasm and membrane was examined by immunohistochemical method. The data collected was analyzed using SPSS16 by ANOVA and Chi-square. P < 0.05 was considered as statistically significant.

Results:

The HER3 expression had positive results in 52.4% of OKC, 50% of DC and only 20% of RC samples. There was a significant difference between HER3 expression in OKCs and RCs.

Conclusions:

The HER3 expression in developmental odontogenic cysts was higher than that in inflammatory odontogenic cysts. The higher rate of HER3 expression in OKC may justify inherent growth potential, stimulation-independent proliferation capability, invasive growth and high recurrence rate of the cyst accepted today as a tumor.

Violacein, an indole-derived purple-colored natural pigment produced by Janthinobacterium lividum, inhibits the growth of head and neck carcinoma cell lines both in vitro and in vivo

Violacein (VIO; 3-[1,2-dihydro-5-(5-hydroxy-1H-indol-3-yl)-2-oxo-3H-pyrrol-3-ylidene]-1,3-dihydro-2H-indol-2-one), an indole-derived purple-colored pigment, produced by a limited number of Gram-negative bacteria species, including Chromobacterium violaceum and Janthinobacterium lividum, has been demonstrated to have anti-cancer activity, as it interferes with survival transduction signaling pathways in different cancer models. Head and neck carcinoma (HNC) represents the sixth most common and one of the most fatal cancers worldwide. We determined whether VIO was able to inhibit head and neck cancer cell growth both in vitro and in vivo. We provide evidence that VIO treatment of human and mouse head and neck cancer cell lines inhibits cell growth and induces autophagy and apoptosis. In fact, VIO treatment increased PARP-1 cleavage, the Bax/Bcl-2 ratio, the inhibition of ERK1 and ERK2 phosphorylation, and the expression of light chain 3-II (LC3-II). Moreover, VIO was able to induce p53 degradation, cytoplasmic nuclear factor kappa B (NF-κB) accumulation, and reactive oxygen species (ROS) production. VIO induced a significant increase in ROS production. VIO administration was safe in BALB/c mice and reduced the growth of transplanted salivary gland cancer cells (SALTO) in vivo and prolonged median survival. Taken together, our results indicate that the treatment of head and neck cancer cells with VIO can be useful in inhibiting in vivo and in vitro cancer cell growth. VIO may represent a suitable tool for the local treatment of HNC in combination with standard therapies.

Epidermal growth factor receptor imaging in human head and neck cancer xenografts

Molecular imaging of specific biomarkers can have prognostic, predictive or monitoring value in head and neck squamous cell carcinoma (HNSCC). The epidermal growth factor receptor (EGFR) is involved in various radiation resistance mechanisms as it steers the pathways related to DNA damage repair, proliferation, hypoxia and apoptosis. Radiolabeled labeled F(ab')2 fragments of the EGFR antibody cetuximab can be applied for non-invasive imaging of this receptor. Preclinical studies have shown that radioresistant tumors had a higher tracer uptake after irradiation, probably due to upregulation of membranous EGFR, thereby increasing target availability possibly as a compensation mechanism. Tumors with increased EGFR availability were also more responsive to the EGFR inhibitor cetuximab. Potentially, radionuclide imaging of the EGFR can be applied for monitoring treatment regimens in clinical practice.

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.

Resveratrol potentiates the in vitro and in vivo anti-tumoral effects of curcumin in head and neck carcinomas

The survival rate of head and neck squamous cell carcinomas (HNSCC) patients has not considerably changed over the last two decades. Polyphenols inhibit the growth of cancer cells. We determined whether the combination of Resveratrol (RES) and Curcumin (CUR) enhanced their in vitro and in vivo antitumor activities on HNSCC cell lines compared to the single compounds. We provide evidence that RES potentiated the apoptotic effect and reduced the IC50 of CUR on HNSCC cell lines. The model of compounds interaction indicated the onset of an additive effect of the two compounds compared to the single treatment after decrease of their concentrations. RES+CUR compared to CUR increased the PARP-1 cleavage, the Bax/Bcl-2 ratio, the inhibition of ERK1 and ERK2 phosphorylation, and the expression of LC3 II simultaneously with the formation of autophagic vacuoles. RES and CUR induced cytoplasmic NF-κB accumulation. RES+CUR administrations were safe in BALB/c mice and reduced the growth of transplanted salivary gland cancer cells (SALTO) more efficiently than CUR. Overall, combinations of CUR and RES was more effective in inhibiting in vivo and in vitro cancer growth than the treatment with CUR. Additional studies will be needed to define the therapeutic potential of these compounds in combination.

ERBB3 as an independent prognostic marker for nasopharyngeal carcinoma

Aim

Although the ERBB proteins have been shown to be associated in many types of human tumours and serve as important cancer therapeutic targets, however, data regarding the expression and clinical relevance of ERBBs in nasopharyngeal carcinoma (NPC) are still conflicting. The aim of this study is to investigate the expression pattern of all ERBB members simultaneously in NPC tissues using immunohistochemistry and determine their clinical relevance.

Methods

The expression of all members of ERBB proteins was evaluated using immunohistochemistry on 82 NPC tissue samples. Relationship between the ERBB protein expression, clinicopathological parameters and patient outcome was assessed using univariate and multivariate analyses.

Results

We found that ERBB1, ERBB2 and ERBB3 were strongly expressed in the normal nasopharyngeal epithelial cells. A marked reduction of ERBB1 and ERBB2 expression in NPC was observed compared with the non-cancerous tissues. 76 of 82 (92.7%) cases were ERBB3-positive, while ERBB4 was not expressed in both normal and NPC. The univariate log-rank analysis showed that regional lymph node metastasis, systemic metastasis, recurrence and ERBB3 expression were associated with patient survival. The ERBB3 expression was not correlated to other clinicopathological factors. Furthermore, multivariate analysis revealed that ERBB3 expression was an independent prognostic factor influencing patient survival.

Conclusions

Our results suggested that the expression of ERBB3 is associated with patient survival and could serve as a novel and valuable predictor for prognostic evaluation of patients with NPC.

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.

Upregulation of epidermal growth factor receptor 4 in oral leukoplakia

In the present study, we investigate the expression profile of the epidermal growth factor receptor family, which comprises EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3 and HER4/ErbB4 in oral leukoplakia (LP). The expression of four epidermal growth factor receptor (EGFR) family genes and their ligands were measured in LP tissues from 14 patients and compared with levels in 10 patients with oral lichen planus (OLP) and normal oral mucosa (NOM) from 14 healthy donors by real-time polymerase chain reaction (PCR) and immunohistochemistry. Synchronous mRNA coexpression of ErbB1, ErbB2, ErbB3 and ErbB4 was detected in LP lesions. Out of the receptors, only ErbB4 mRNA and protein was more highly expressed in LP compared with NOM tissues. These were strongly expressed by epithelial keratinocytes in LP lesions, as shown by immunohistochemistry. Regarding the ligands, the mRNA of Neuregulin2 and 4 were more highly expressed in OLP compared with NOM tissues. Therefore, enhanced ErbB4 on the keratinocytes and synchronous modulation of EGFR family genes may contribute to the pathogenesis and carcinogenesis of LP.

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.

Loss of CD151/Tspan24 from the complex with integrin α3β1 in invasive front of the tumour is a negative predictor of disease-free survival in oral squamous cell carcinoma

OBJECTIVES

The study aimed to assess the role of CD151-integrin α3β1 (INGA3) complex as a potential prognostic indicator in OSCC and to examine whether mapping of its expression in the invasive front separately from that in the rest of the tumour would have an impact on the predictive value of the results. CD151/INGA3 profiles were compared with that of EGFR.

MATERIALS AND METHODS

Protein distributions were analysed either in the whole tumour (W) or separately, (i) the main tumour mass (TU) and (ii) the invasive front (IF) in 83 OSCC samples using immunohistochemistry.

RESULTS AND CONCLUSION

There was no statistical association between any of the proteins scored in W and clinicopathologic features or patient survival. When examined separately, significant associations were shown for (i) CD151 and EGFR in TU (p=0.036) and (ii) tumour grade and EGFR in both TU (p=0.045) and IF (p=0.030). INGA3 was present predominantly in the tumour-host interface, significantly stronger in IF than TU (p=0.021). An association with 5-year disease-free survival was close to significant for INGA3 (TU and IF) (p=0.050) but not the CD151/INGA3 complex. Expression of CD151/INGA3 at the IF might reflect tumour behaviour pertinent to patient outcome.

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.

pEGFR-Tyr 845 expression as prognostic factors in oral squamous cell carcinoma: a tissue-microarray study with clinic-pathological correlations

The EGFR (epidermal growth factor receptor) a member of the family of transmembrane protein kinase receptors known as the erbB family shows a significant correlation with the presence of metastases and poorly differentiated oral cancer. Aim of the present work is to define the key-role of EGFR in oral cancer prognosis. We have analyzed the EGFR expression on 149 cases of oral squamous cell cancers (OSCC) and we have found that it was poorly expressed in normal oral epithelium, but its expression was significantly increased in OSCCs. Moreover, we have recorded that both pEGFR-Tyr 845 and pEGFR-Tyr 1068 were mainly distributed in high histological grading and in advanced stages. Western blotting has confirmed the total absence of EGFR phosphorylation in normal oral epithelium and the higher level of protein phosphorylation in representative cases of OSCCs. The EGF-R amplification was found by fluorescence in situ hybridization (FISH) in 14% of OSCC; interestingly, EGF-R amplification was mainly observed in OSCC with higher histological grading (G2 and G3) and advanced stage (pT4) sub-groups. Kaplan-Meyer survival analysis suggested that patients with positive pEGFR-Tyr 845 tumors had a worse prognosis and were bad responders to chemotherapy. These results confirm the central role of EGF-R activation status as a prognostic biomarker in OSCC.

Multiplex photoacoustic molecular imaging using targeted silica-coated gold nanorods

The establishment of multiplex photoacoustic molecular imaging to characterize heterogeneous tissues requires the use of a tunable, thermally stable contrast agent targeted to specific cell types. We have developed a multiplex photoacoustic imaging technique which uses targeted silica-coated gold nanorods to distinguish cell inclusions in vitro. This paper describes the use of tunable targeted silica-coated gold nanorods (SiO(2)-AuNRs) as contrast agents for photoacoustic molecular imaging. SiO(2)-AuNRs with peak absorption wavelengths of 780 nm and 830 nm were targeted to cells expressing different cell receptors. Cells were incubated with the targeted SiO(2)-AuNRs, incorporated in a tissue phantom, and imaged using multiwavelength photoacoustic imaging. We used photoacoustic imaging and statistical correlation analysis to distinguish between the unique cell inclusions within the tissue phantom.

Phospholipase C-gamma1 is required for the epidermal growth factor receptor-induced squamous cell carcinoma cell mitogenesis

The epidermal growth factor receptor (EGFR) is a key driver in the process of squamous cell carcinoma (SCC) cell mitogenesis. Phospholipase C-gamma1 (PLC-gamma1) is a downstream target of EGFR signaling, but the role and necessity of PLC-gamma1 in EGFR-induced cell mitogenesis remain unclear. In the present study, we report an elevated expression of PLC-gamma1 in human SCC biopsies relative to adjacent normal epidermis, and in human SCC cell lines compared to normal human keratinocytes. EGFR-induced SCC cell mitogenesis was blocked by small interfering RNA knockdown of PLC-gamma1. However, inhibition of the catalytic activity of phospholipase C had no effect on EGFR-induced SCC cell mitogenesis. In response to the EGFR ligand epidermal growth factor (EGF), PLC-gamma1 was translocated not only to the plasma membrane but also to the nucleus. These data suggest that PLC-gamma1 is required for EGFR-induced SCC cell mitogenesis and the mitogenic function of PLC-gamma1 is independent of its lipase activity.

Biomolecular markers in cancer of the tongue

The incidence of tongue cancer is increasing worldwide, and its aggressiveness remains high regardless of treatment. Genetic changes and the expression of abnormal proteins have been frequently reported in the case of head and neck cancers, but the little information that has been published concerning tongue tumours is often contradictory. This review will concentrate on the immunohistochemical expression of biomolecular markers and their relationships with clinical behaviour and prognosis. Most of these proteins are associated with nodal stage, tumour progression and metastases, but there is still controversy concerning their impact on disease-free and overall survival, and treatment response. More extensive clinical studies are needed to identify the patterns of molecular alterations and the most reliable predictors in order to develop tailored anti-tumour strategies based on the targeting of hypoxia markers, vascular and lymphangiogenic factors, epidermal growth factor receptors, intracytoplasmatic signalling and apoptosis.

Targeting EGFR resistance networks in head and neck cancer

A core set of oncoproteins is overexpressed or functionally activated in many types of cancer, and members of this group have attracted significant interest as subjects for development of targeted therapeutics. For some oncoproteins such as EGFR/ErbB1, both small molecule and antibody agents have been developed and applied in the clinic for over a decade. Analysis of clinical outcomes has revealed an initially unexpected complexity in the response of patients to these agents. Diverse factors, including developmental lineage of the tumor progenitor cell, co-mutation or epigenetic modulation of genes encoding proteins in an extended EGFR signaling network or regulating core survival responses in individual tumors, and environmental factors including inflammatory agents and viral infection, all have been identified as modulating response to treatment with EGFR-targeted drugs. Second and third generation therapeutic strategies increasingly incorporate knowledge of cancer type-specific signaling environments, in a more personalized treatment approach. This review takes squamous cell carcinoma of the head and neck (SCCHN) as a specific example of an EGFR-involved cancer with idiosyncratic biological features that influence design of treatment modalities, with particular emphasis on commonalities and differences with other cancer types.

EGFR protein overexpression and gene copy number increases in oral tongue squamous cell carcinoma

New promising therapeutic agents targeting epidermal growth factor receptor (EGFR) have been developed although clinical information concerning EGFR status in oral tongue squamous cell carcinoma (OTSCC) is limited. We investigated EGFR protein expression and gene copy numbers in 78 pretreatment OTSCC paraffin samples. EGFR protein expression was found in all 78 tumours, of which 72% showed an intense staining. Fifty-four percent of the tumours had high (> or =four gene copies) EGFR gene copy numbers. EGFR gene copy number was significantly associated with EGFR protein expression (P=0.002). Pretreatment EGFR staining intensity tended to be associated with non-pathological complete remission after preoperative radiotherapy for Stage II OTSCC. No correlation was found between EGFR status and survival. EGFR FISH results were significantly (P=0.003) higher in more advanced tumours (Stages II, III and IV) than in the tumours in Stage I. Non-smokers exhibited a significantly higher EGFR gene copy number and protein overexpression in Stages I and II OTSCC than smokers (P=0.001, P=0.009). In conclusion, EGFR was found to be overexpressed in all OTSCCs making this cancer type interesting for exploring new therapeutic agents targeting the EGFR receptor.

Functional genomic analysis identified epidermal growth factor receptor activation as the most common genetic event in oral squamous cell carcinoma

A 250K single-nucleotide polymorphism array was used to study subchromosomal alterations in oral squamous cell carcinoma (OSCC). The most frequent amplification was found at 7p11.2 in 9 of 29 (31%) oral cancer patients. Minimal genomic mapping verified a unique amplicon spanning from 54.6 to 55.3 Mb on chromosome 7, which contains SEC61G and epidermal growth factor receptor (EGFR). Results from fluorescence in situ hybridization, transcriptome, and immunohistochemistry analyses indicated that the expression level of EGFR, but not of SEC61G, was up-regulated and tightly correlated with DNA copy number in 7p11.2 amplified tumors. Among the members of the erbB family, EGFR (HER1) was found to be the most frequently amplified and highly expressed gene in both human and mouse oral tumors (P < 0.01). Genes for downstream effectors of EGFR, including KRAS, mitogen-activated protein kinase 1, and CCND1, were also found amplified or mutated, which resulted in activation of EGFR signaling in 55% of OSCC patients. Head and neck squamous cancer cells with different EGFR expression levels showed differential sensitivity to antitumor effects of AG1478, a potent EGFR inhibitor. AG1478-induced EGFR inactivation significantly suppressed tumor development and progression in a mouse oral cancer model. Our data suggest that EGFR signaling is important in oral cancer development and that anti-EGFR therapy would benefit patients who carry the 7p11.2 amplicon in their tumors.

ErbB receptors in the biology and pathology of the aerodigestive tract

The most common sites of malignancies in the aerodigestive tract include the lung, head and neck and the esophagus. Esophageal adenocarcinomas (EA), esophageal squamous cell carcinomas (ESCC), and squamous cell carcinomas of the head and neck (SCCHN) are the primary focus of this review. Traditional treatment for aerodigestive tract cancers includes primary chemoradiotherapy (CRT) or surgical resection followed by radiation (or CRT). Recent developments in treatment have focused increasingly on molecular targeting strategies including cetuximab (a monoclonal antibody against epidermal growth factor receptor (EGFR)). Cetuximab was FDA approved in 2006 for treatment of SCCHN, underscoring the importance of understanding the biology of these malignancies. EGFR is a member of the ErbB family of growth factor receptor tyrosine kinases. The major pathways activated by ErbB receptors include Ras/Raf/MAPK; PI3K/AKT; PLCgamma and STATs, all of which lead to the transcription of target genes that may contribute to aerodigestive tumor progression. This review explores the expression of ErbB receptors in EA, ESCC and SCCHN and the signaling pathways of EGFR in SCCHN.

Differential expression of fatty acid synthase (FAS) and ErbB2 in nonmalignant and malignant oral keratinocytes

The aim of this study was to investigate fatty acid synthase (FAS) and ErbB2 expression in nonmalignant oral epithelium and oral or head and neck squamous cell carcinomas (OSCC/HNSCC). Morphologically normal, hyperkeratotic, and dysplastic oral epithelium as well as well-differentiated and poorly differentiated OSCC were immunohistochemically evaluated for FAS, ErbB2, and Ki-67. These proteins were also analyzed in a tissue microarray with 55 HNSCC. SCC-9 cells were used to study FAS and ErbB2 during differentiation. FAS expression was higher in hyperkeratosis, dysplasias, and OSCC than in normal epithelium. Well-differentiated OSCC/HNSCC were more positive for FAS than the poorly differentiated tumors. ErbB2 was observed at the surface of nonmalignant and well-differentiated OSCC/HNSCC keratinocytes and in the cytoplasm of poorly differentiated cells. Ki-67 index was progressively higher from normal oral epithelium to OSCC, inversely correlated with cell surface ErbB2, and positively correlated with intracytoplasmic ErbB2. Finally, SCC-9 cell cultures were enriched in membrane ErbB2-positive cells after differentiation by anchorage deprivation. In conclusion, FAS is overexpressed in OSCC/HNSCC and hyperkeratotic oral epithelium and ErbB2 is found at the cell surface of differentiating keratinocytes and in the cytoplasm of poorly differentiated tumor cells. Ki-67 index is higher in epithelial dysplasias and OSCC than in morphologically normal oral epithelium.

ErbB2 and fatty acid synthase (FAS) expression in 102 squamous cell carcinomas of the tongue: Correlation with clinical outcomes

The oncoprotein ErbB2 (HER-2/neu) is a tyrosine kinase cell surface receptor overexpressed in several human malignancies, including oral squamous cell carcinoma (OSCC). ErbB2 was recently shown to regulate the expression of fatty acid synthase (FAS), a multifunctional enzyme complex responsible for the de novo biosynthesis of saturated fatty acids. Here we evaluated the relationship between the immunohistochemical expression of ErbB2, FAS, and Ki-67 with the clinicopathologic characteristics of tongue squamous cell carcinoma (SCC). One hundred and two patients with tongue SCC treated from 1990 to 1995 were studied. Clinical and treatment data were obtained from the medical records and histopathological features revised. Paraffin-embedded tissues were submitted to standard immunohistochemical reactions for ErbB2, FAS and Ki-67. A strong positive correlation between ErbB2 labeling at the cell membrane and FAS expression was found in the tongue SCC samples (p<0.0001). The intracytoplasmatic expression of ErbB2 as well as Ki-67 nuclear staining were significantly associated with a high risk of recurrence by predicting both disease free survival (log-rank test, p=0.0096 and p=0.0047, respectively) and overall survival (log-rank test, p=0.0029 and p=0.0001, respectively). Taken together, our results suggest that the immunolocalization of ErbB2 at the cell surface of malignant oral keratinocytes is linked to FAS expression whereas the intracytoplasmatic ErbB2 or Ki-67 staining predict high risk of recurrence of tongue SCC.

The ERBB3 receptor in cancer and cancer gene therapy

ERBB3, a member of the epidermal growth factor receptor (EGFR) family, is unique in that its tyrosine kinase domain is functionally defective. It is activated by neuregulins, by other ERBB and nonERBB receptors as well as by other kinases, and by novel mechanisms. Downstream it interacts prominently with the phosphoinositol 3-kinase/AKT survival/mitogenic pathway, but also with GRB, SHC, SRC, ABL, rasGAP, SYK and the transcription regulator EBP1. There are likely important but poorly understood roles for nuclear localization and for secreted isoforms. Studies of ERBB3 expression in primary cancers and of its mechanistic contributions in cultured cells have implicated it, with varying degrees of certainty, with causation or sustenance of cancers of the breast, ovary, prostate, certain brain cells, retina, melanocytes, colon, pancreas, stomach, oral cavity and lung. Recent results link high ERBB3 activity with escape from therapy targeting other ERBBs in lung and breast cancers. Thus a wide and centrally important role for ERBB3 in cancer is becoming increasingly apparent. Several approaches for targeting ERBB3 in cancers have been tested or proposed. Small inhibitory RNA (siRNA) to ERBB3 or AKT is showing promise as a therapeutic approach to treatment of lung adenocarcinoma.

The hamster model of sequential oral oncogenesis

Oral squamous cell carcinoma (OSCC) is a common cancer characterised by low survival rate and poor prognosis. The multistep process of oral carcinogenesis is affected by multiple genetic events such as alterations of oncogenes and tumour suppressor genes. The use of appropriate experimental animal models that accurately represent the cellular and molecular changes which are associated with the initiation and progression of human oral cancer is of crucial importance. The Syrian golden hamster cheek pouch oral carcinogenesis model is the best known animal system that closely correlates events involved in the development of premalignant and malignant human oral cancers. Therefore, we established an experimental system of chemically induced oral carcinogenesis in hamsters, in order to study different stages of tumour formation: normal mucosa, hyperkeratosis, hyperplasia, dysplasia, early invasion, well differentiated OSCC and moderately differentiated OSCC. We investigated the expression of oncogenes EGFR, erbB2, erbB3, FGFR-2, FGFR-3, c-myc, N-ras, ets-1, H-ras, c-fos and c-jun, apoptosis markers Bax and Bcl-2, tumour suppressor genes p53 and p16, and cell proliferation marker Ki-67 in the sequential stages of hamster oral oncogenesis. Here, we describe the findings of the experimental model in regard to the involvement of signal transduction pathways in every stage of cancer development. Increased apoptosis and cell proliferation were observed in early stages of oral oncogenesis. Furthermore, the increased expression of transmembrane receptors (EGFR, erbB2, FGFR-2 and FGFR-3) as well as the increased expression of nuclear transcriptional factors in early stages of oral cancer indicates that these molecules may be used as early prognostic factors for the progression of OSCC. Since the expression of both H-ras and N-ras do not seem to affect signal transduction during oral oncogenesis, it can be assumed that a different signalling pathway, such as the PI3K and/or PLCgamma pathway, may be implicated in the pathogenesis of OSCC.

Chemoprevention of 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamster cheek pouch by topical application of a dual inhibitor of epidermal growth factor receptor (EGFR) and ErbB2 tyrosine kinases

Oral cancer is a common neoplasm worldwide with tobacco and alcohol being the major etiological factors contributing to its pathogenesis. Epidermal growth factor receptor (EGFR) and ErbB2 are known to be involved in the development of oral cancer with the former up-regulated in up to 90% human cases. The goal of this study was to evaluate the chemopreventive effects of a dual inhibitor of EGFR and ErbB2 tyrosine kinases, GW2974, in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch model. A short-term experiment (3-week topical DMBA followed by 1-week topical GW2974) was conducted to examine the effects of GW2974 on aberrant arachidonic acid (AA) metabolism and cell proliferation in the hamster oral epithelium. Topical application of 0.1 ml GW2974 (160 microM, three times a week) significantly reduced the levels of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), 5-, 12-, 15-hydroxyeicosatetraenoic acid (HETE), and cell proliferation (BrdU-labeling index). In a long-term post-initiation experiment (6-week topical DMBA followed by 18-week topical GW2974), GW2974 (4 mM and 8 mM) significantly inhibited the incidence, number and size of visible tumors. Under microscope, the numbers of oral lesions (hyperplasia, dysplasia, carcinoma) and the incidence of squamous cell carcinoma (SCC) were also significantly suppressed by GW2974. In summary, our study indicated that dual inhibition of EGFR and ErbB2 tyrosine kinases by GW2974 was effective in preventing oral carcinogenesis in DMBA-induced hamster cheek pouch model. GW2974 exerted its chemopreventive effects in part by suppressing aberrant AA metabolism.

Enhancement of erbB2 and erbB3 expression during oral oncogenesis in diabetic rats

PURPOSE

The expression of erbB2 and erbB3 receptors was investigated in an experimental model of chemically induced oral carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats.

METHODS

Thirteen diabetic and twelve normal rats developed precancerous and cancerous lesions after 4-nitroquinoline-N-oxide treatment, while six diabetic and six normal animals were used as controls. Sections of biopsies from all animals were classified histologically in the following categories: normal mucosa, hyperplasia, dysplasia, early invasion, well- and moderately-differentiated squamous cell carcinoma. Each section was studied immunohistochemically using monoclonal antibodies against erbB2 and erbB3 proteins and six representative histological regions in each section were analysed.

RESULTS

The erbB2 was expressed at very low levels in normal rats, while in diabetic animals its expression was significantly increased during early invasion (P = 0.04). The erbB3 expression was significantly elevated in well-differentiated carcinoma in normal animals (P = 0.01), while in diabetic animals it was significantly increased during oral mucosal hyperplasia and dysplasia (P = 0.03 and 0.0007, respectively). The comparison of erbB2 expression between diabetic and normal rats revealed significant differences in all stages except for the tumor stage of moderately differentiated carcinoma (P = 0.01, 0.00001, 0.00001, 0.003, and 0.00001). In regard to erbB3 expression, significant differences between diabetic and normal rats existed only in normal, non-cancerous and precancerous stages (P = 0.007, 0.0001, 0.0003).

CONCLUSIONS

It seems that diabetes enhances the expression of both erbB2 and erbB3 in certain stages of oral oncogenesis possibly resulting in promotion of cell proliferation and inhibition of apoptosis.

ERBB receptors in developing, dysplastic and malignant oral epithelia

Some oral squamous cell carcinomas (OSCCs) overexpress epidermal growth factor receptor (EGFR) but little is known about the receptor system overall during oral carcinogenesis. We studied all four ERBB receptors (EGFR, ERBB2-4) in developing (n=2), normal (n=7), dysplastic (n=23) and malignant (n=26) oral epithelia by means of immunohistochemistry. The investigations were supplemented by conducting reverse transcription-polymerase chain reactions in relation to 13 OSCC samples. All four ERBB receptors were detected in developing oral epithelium and, to a lesser degree, in mature oral epithelium. An increase in EGFR immunoreactivity was seen in 61% and 54% of dysplasias and OSCCs, respectively. The corresponding percentages for ERBB2 were 48 and 12, for ERBB3 48 and 43. ERBB4 nuclear staining was increased in 30% of dysplasias and 26% of OSCCs. Changes in ERBB receptor mRNA levels were not statistically significant. The results show that ERBB receptor profiles are specific to each tumour. Increased nuclear translocation of ERBB4 in some OSCCs may alter transcription of target genes and be associated with cancer progression. This information may be useful for clinicians as EGFR inhibitors are becoming treatment options in modern oncology.

Epidermal growth factor receptor biology in head and neck cancer

Epidermal growth factor receptor (EGFR) is overexpressed in several epithelial malignancies, including head and neck squamous cell carcinoma (HNSCC), which exhibits EGFR overexpression in up to 90% of tumors. EGFR ligands such as transforming growth factor alpha are also overexpressed in HNSCC. EGFR plays a critical role in HNSCC growth, invasion, metastasis and angiogenesis. However, EGFR inhibitors as monotherapy have yielded only modest clinical outcomes. Potential mechanisms for lack of response to EGFR inhibition in HNSCC include constitutive activation of signaling pathways independent of EGFR, as well as genetic aberrations causing dysregulation of the cell cycle. EGFR-directed therapy may be optimized by identifying and selecting those HNSCC patients most likely to benefit from EGFR inhibition. Resistance to EGFR inhibition may be circumvented by combination therapy employing EGFR inhibitors together with other treatment modalities.

Analysis of c-ErbB1/epidermal growth factor receptor and c-ErbB2/HER-2 expression in bronchial dysplasia: evaluation of potential targets for chemoprevention of lung cancer

PURPOSE

Lung cancer is preceded by a premalignant phase during which intervention could decrease associated morbidity and mortality. Molecular characterization of factors involved in controlling progression of bronchial dysplasias will provide markers of premalignant change and identify targets for chemoprevention.

EXPERIMENTAL DESIGN

Immunohistochemical analysis of epidermal growth factor receptor (EGFR; c-ErbB1/EGFR), HER-2/neu (c-ErbB2/HER-2), Ki-67, and minichromosome maintenance protein 2 (MCM2) expression in bronchial dysplasia was undertaken to characterize molecular alterations associated with the progression of these lesions in 268 bronchoscopically obtained biopsies from 134 subjects.

RESULTS

Analysis of biopsies with the most severe diagnosis from each subject showed a linear relationship between increasing marker expression and severity of dysplastic change for EGFR (P < 0.001), Ki-67 (P < 0.001), and MCM2 (P = 0.001) but not HER-2 (P = 0.102). Increased expression of either EGFR or HER-2 was associated with increased levels of Ki-67 and MCM2 expression, and combined overexpression of these receptors was associated with the highest levels of proliferation, suggesting a synergistic effect. Finally, the lack of an associated trend toward increased EGFR expression when comparing the worst and best biopsies within each subject indicated a potential field effect in the induction of EGFR expression.

CONCLUSIONS

The results suggest a prominent role for EGFR overexpression in the development and progression of bronchial dysplasia and provide rationale for exploring inhibition of EGFR signaling in lung cancer chemoprevention.

Combined expression of p53, cyclin D1 and epidermal growth factor receptor improves estimation of prognosis in curatively resected oral cancer

p53, cyclin D1 and epidermal growth factor receptor (EGFR) are molecular markers that regulate the cell cycle or cell growth and play important roles in tumor development and progression. In this study, we examined the impact of immunohistochemical expression of these markers on tumor progression in 140 oral cancers. p53, cyclin D1 and EGFR were expressed in 64 cases (46%), 54 cases (39%) and 54 cases (39%), respectively, but there was no inter-relationship between any two of these markers. In the association of these markers with clinicopathological features, EGFR expression alone was significantly associated with poor differentiation (P=0.0008) and invasive growth pattern (P=0.0003). Any of these markers, including EGFR, had no significant impact on survival. Coexpression of all these markers, however, was significantly associated with invasive growth pattern (P=0.0149) and shortened survival (P=0.0181), and was a significant and independent unfavorable prognostic factor (P=0.0002), along with tumor size (P=0.0040), nodal metastasis (P=0.0137) and growth pattern (P=0.0017) in a multivariate analysis. Simultaneous coexpression of these markers in oral cancers might prove to be a useful indicator for identification of low- or high-risk patients.

Proteolytic cleavage and phosphorylation of a tumor-associated ErbB4 isoform promote ligand-independent survival and cancer cell growth

The ErbB1 and ErbB2 receptors are oncogenes with therapeutic significance in human cancer, whereas the transforming potential of the related ErbB4 receptor has remained controversial. Here, we have addressed whether four alternatively spliced ErbB4 isoforms differ in regulating cellular responses relevant for tumor growth. We show that the two tumor necrosis factor-alpha converting enzyme (TACE)-cleavable ErbB4 isoforms (the juxtamembrane [JM]-a isoforms) were overexpressed in a subset of primary human breast cancers together with TACE. The overexpression of the JM-a cytoplasmic (CYT)-2 ErbB4 isoform promoted ErbB4 phosphorylation, survival of interleukin-3-dependent cells, and proliferation of breast cancer cells even in the absence of ligand stimulation, whereas activation of the other three ErbB4 isoforms required ligand stimulation. Ligand-independent cellular responses to ErbB4 JM-a CYT-2 overexpression were regulated by both tyrosine kinase activity and a two-step proteolytic generation of an intracellular receptor fragment involving first a TACE-like proteinase, followed by gamma-secretase activity. These data suggest a novel transforming mechanism for the ErbB4 receptor in human breast cancer that is 1) specific for a single receptor isoform and 2) depends on proteinase cleavage and kinase activity but not ligand activation of the receptor.

Biological significance of c-erbB family oncogenes in head and neck cancer

Squamous cell carcinoma of the head and neck (SCCHN) tends to run an aggressive course and the prognosis has remained virtually unchanged in recent decades. The development of novel therapeutic strategies to improve patient outcome centres on the biology of the disease, namely the pivotal c-erbB family of growth factor receptors. c-erbB1 (or epidermal growth factor receptor, EGFR), is key to the pathogenesis of SCCHN and plays a central role in a complex network of downstream integrated signalling pathways. EGFR overexpression, detected in up to 90% of SCCHN, correlates with an increased risk of locoregional tumour relapse following primary therapy and relative resistance to treatment. The biological sequelae of erbB receptor activation are not simply cell proliferation, but also inhibition of apoptosis, enhanced migration, invasion, angiogenesis and metastasis: the 'hallmarks of cancer' [1]. As EGFR overexpression is associated with a poor clinical outcome in SCCHN, this receptor is attractive as a therapeutic target and the successful development of targeted therapies represents a paradigm shift in the medical approach to head and neck cancer. However, the extensive cross talk between signalling pathways, the multiple molecular aberrations and genetic plasticity in SCCHN all contribute to inherent and acquired resistance to both conventional and novel therapies. Understanding the cancer cell biology, in particular the significance of co-expression of c-erbB (and other) receptors, and the cell survival stimuli from (for example) activation of the phosphoinositide 3-kinase (PI3-kinase) cascade is fundamental to overcome current limitations in biologically targeted therapies.

Tumor cell invasion and survival in head and neck cancer

Squamous cell carcinoma (SCC) is the primary tumor type in head and neck cancer. Typically, these tumor cells show persistent invasion that frequently leads to local recurrence and distant lymphatic metastasis. The process of invasion involves concurrent infiltration and destruction of adjacent tissues. As with normal mucosal epithelium, SCC cells express receptors that mediate cell-extracellular matrix (ECM) adhesion (integrins) and cell-cell adhesion (cadherins). Both receptor families represent important signaling devices that are capable of promoting survival and proliferation. Recent results indicate that integrins and cadherins cooperate to regulate invasive behavior. During SCC invasion, cells actively migrate through the surrounding ECM with the simultaneous remodeling of their intercellular adhesions. During invasion, integrin receptor engagement with specific ECM ligands along with concurrent remodeling of cadherin adhesions induces changes in the cytoskeleton though modulation of the activities of Rho family members. Tumor development and progression of SCC proceeds with the generation of variant cells with potential alterations in expression of adhesion receptors, and their associated signaling pathways lead to a highly invasive and metastatic phenotype. Understanding the molecular events that define this subset of invasive cells will facilitate the development of new treatment strategies.

The influence of epidermal growth factor receptor and tumor differentiation on the response to accelerated radiotherapy of squamous cell carcinomas of the head and neck in the randomized DAHANCA 6 and 7 study

BACKGROUND AND PURPOSE

Reduction of the overall treatment time of radiotherapy has increased locoregional control and disease specific survival in squamous cell carcinomas of the head and neck (HNSCC), but the response is heterogeneous. EGFr is often overexpressed in HNSCC and has been related to the repopulation taking place during radiotherapy. The aim of the current study was to address the influence of EGFr and histopathological differentiation when the overall treatment time of radiotherapy was moderately reduced.

PATIENTS AND METHODS

Eight hundred and three patients with representative pretreatment tissue samples from the randomized DAHANCA 6 and 7 study of 5 vs. 6 fx/wk of radiotherapy. EGFr was visualized using immunohistochemistry and separated into high and low expression before correlation with clinical data.

RESULTS

Tumors with high EGFr (84%) responded better to moderately accelerated radiotherapy, than carcinomas with low EGFr, using locoregional control as endpoint and a similar pattern was seen, stratifying by well/moderate vs. poor tumor differentiation. Therefore, a combined parameter was constructed showing a more prominent separation of response: tumors with high EGFr and well/moderate differentiation did benefit from moderate acceleration of treatment regarding locoregional control, HR 0.54 (0.37-0.78), whereas such an effect was not seen in tumors with low EGFr and/or poor differentiation, HR 0.8 (0.51-1.25). These results reflected the disease specific survival as well and were confirmed in multivariable analyses.

CONCLUSIONS

Moderately accelerated fractionation is superior to conventional treatment in HNSCC but the response is heterogeneous and may be predicted by high expression of EGFr and well/moderate tumor differentiation.

Gene expression signature predicts lymphatic metastasis in squamous cell carcinoma of the oral cavity

Metastasis via the lymphatics is a major risk factor in squamous cell carcinoma of the oral cavity (OSCC). We sought to determine whether the presence of metastasis in the regional lymph node could be predicted by a gene expression signature of the primary tumor. A total of 18 OSCCs were characterized for gene expression by hybridizing RNA to Affymetrix U133A gene chips. Genes with differential expression were identified using a permutation technique and verified by quantitative RT-PCR and immunohistochemistry. A predictive rule was built using a support vector machine, and the accuracy of the rule was evaluated using crossvalidation on the original data set and prediction of an independent set of four patients. Metastatic primary tumors could be differentiated from nonmetastatic primary tumors by a signature gene set of 116 genes. This signature gene set correctly predicted the four independent patients as well as associating five lymph node metastases from the original patient set with the metastatic primary tumor group. We concluded that lymph node metastasis could be predicted by gene expression profiles of primary oral cavity squamous cell carcinomas. The presence of a gene expression signature for lymph node metastasis indicates that clinical testing to assess risk for lymph node metastasis should be possible.

The epidermal growth factor receptor signaling network in head and neck carcinogenesis and implications for targeted therapy

Improved understanding of the molecular signaling pathways that mediate cellular transformation has led to the development of novel strategies for the treatment of cancer. The epidermal growth factor receptor (EGFR), a transmembrane protein with intrinsic tyrosine kinase activity, transduces important signals from the surface of epithelial cells to the intracellular domain. Aberrant signaling through EGFR plays a key role in the carcinogenesis of squamous cell carcinomas of the head and neck (SCCHN). SCCHN tend to express high levels of EGFR, and the degree of expression correlates with poor clinical outcome. Since EGFR is present at much higher levels in cancerous lesions than in normal epithelial tissue, the receptor has been implicated as a highly specific therapeutic target for the treatment of SCCHN. EGFR can be abrogated at the extracellular level using either monoclonal antibodies or toxin conjugates that compete with the natural ligand at the binding site of the receptor, and targeting of the EGFR intracellular domain has been achieved by specific inhibitors of tyrosine kinase activity. Antisense strategies use synthesized DNA or RNA oligonucleotides to block the translation of the mRNA sequences that code for the production of the EGFR or other proteins with a role in EGFR-mediated cell signaling. Clinical evaluation of EGFR-specific monoclonal antibodies and tyrosine kinase inhibitors has demonstrated limited toxicity in SCCHN patients, and concurrent administration with standard cytotoxic therapies has produced additive or synergistic antitumor effects.

Identification of DNA copy number changes in microdissected serous ovarian cancer tissue using a cDNA microarray platform

We have established a method for using a cDNA array platform in combination with degenerate oligonucleotide primer polymerase chain reaction (DOP-PCR) and taramide signal amplification (TSA) to identify DNA copy number abnormalities (CNA) in cancer cell lines and cancer cells procured with laser-based microdissection. To determine the sensitivity and specificity for detecting single-copy gain and loss, receiver-operator curve analysis was performed on hybridization signal ratios generated from non-DOP and DOP amplified female and male DNA using a 10,816-element cDNA microarray. A cutoff value of 1.12 and 1.07 average signal ratio for X-chromosomal genes versus autosomal genes provided a sensitivity and specificity of 50 and 79%, respectively, for non-DOP amplified DNA and a sensitivity and specificity of 50 and 72%, respectively, for DOP amplified DNA. We used this approach to identify DNA copy number abnormalities in the ovarian cancer cell line OVCA633, which has previously been shown to have 12p amplification. Transcription profiling of OVCA633 was also performed. Two amplified and overexpressed genes located on 12p11, KRAS2 and LRMP, were identified; these were validated with quantitative real-time PCR. Subsequently, the same approach was used to identify CNAs and gene expression alterations in 11 microdissected serous ovarian adenocarcinoma cases. Validated data revealed amplification and overexpression of ERBB3 and FOS and deletion and underexpression of KRT6 and APXL in more than 50% of the tissue samples. These results show the feasibility of using the cDNA array platform to identify changes in DNA and mRNA copy number simultaneously in microdissected tumor tissues.

Expression of fatty acid synthase, ErbB2 and Ki-67 in head and neck squamous cell carcinoma. A clinicopathological study

Fatty acid synthase (FAS) is a multifunctional enzyme responsible for the synthesis of saturated fatty acids using acetyl-CoA and malonyl-CoA as substrates. Overexpression of FAS has been reported in several human malignancies and suggested as a potential prognostic factor. ErbB2 (Her-2/neu), a transmembrane tyrosine kinase member of the ErbB receptor family, is known to be overexpressed in a variety of tumors and was recently shown to regulate FAS production in breast epithelial cell lines. Herein we analyzed by immunohistochemistry the expression of FAS, ErbB2, and the proliferation marker Ki-67 in 62 head and neck squamous cell carcinoma (HNSCC) samples. Approximately 78% of the cases were positive for FAS or ErbB2 at the cell membrane and 70% of the tumors that showed a high expression of FAS were also strongly positive for ErbB2 (Fisher's exact test, p = 0.01). The immunolabeling for both FAS and ErbB2 was stronger in histologically well-differentiated lesions. Additionally, Ki-67 expression was significantly associated with a poor prognosis (log-rank test, p = 0.03). Taken together, the results presented here suggest that ErbB2 regulates FAS expression in HNSCC and point out Ki-67 as a useful prognostic marker for these tumors.

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.

MUC4 and ErbB2 expression in squamous cell carcinoma of the upper aerodigestive tract: correlation with clinical outcomes

OBJECTIVES/HYPOTHESIS

Expression of the membrane mucin MUC4 has been associated with a variety of malignancies, including squamous cell carcinoma of the upper aerodigestive tract. MUC4 modulates cell signaling pathways as an intramembrane ligand of ErbB2. The hypotheses of the study were that MUC4 expression would correlate with ErbB2 expression and that MUC4 expression would correlate with clinical outcomes in squamous cell carcinoma of the upper aerodigestive tract.

STUDY DESIGN

Retrospective chart review was combined with immunohistochemical analysis of paraffin-embedded tumor specimens from patients treated with initial definitive surgical resection at an academic tertiary care medical center.

METHODS

MUC4 and ErbB2 receptor expression was localized by immunohistochemical studies using archival formalin-fixed and paraffin-embedded tissue. A limited number of fresh-frozen tissues were further analyzed by Western blot. Clinical outcomes and histopathological parameters were determined by retrospective chart review and correlated with immunohistochemical findings.

RESULTS

One hundred fifty-four patients were analyzed with a median follow-up of 12 months among 54 patients who died and 49 months among 100 surviving patients. Membrane expression of MUC4 and ErbB2 was seen in 12% and 13% of tumors, respectively. MUC4 expression was not correlated with pathological grade. A significant correlation was found between MUC4 expression and ErbB2 expression. Multivariate survival analyses revealed that patients whose tumors exhibited MUC4 membrane expression had statistically significant improvement in survival and longer time to recurrence compared with patients whose tumors did not express MUC4 as defined by immunohistochemical staining patterns. No correlations between ErbB2 expression and survival or recurrence were observed.

CONCLUSION

Patients with tumors that retain MUC4 expression exhibit improved survival and decreased recurrence in squamous cell carcinoma of the upper aerodigestive tract. Correlations between MUC4 expression patterns and ErbB2 expression are also observed, suggesting that MUC4-ErbB2 mediated cell signaling pathways may provide insights into this clinical result.

OCGR array: an oral cancer genomic regional array for comparative genomic hybridization analysis

Genetic alterations have been recognized as important events in the carcinogenesis of oral squamous cell carcinoma (OSCC) and have been used as predictors of progression risk. In this study, we have designed an oral cancer-specific human bacterial artificial chromosome (BAC) array, called the oral cancer genomic regional array (OCGR), to detect and fine map copy number alterations in OSCC. This array contains a total of approximately 45 Mbp coverage of nine chromosomal regions reported to be involved in the progression of oral cancer. We demonstrate the detection of copy number alterations in 14 microdissected clinical specimens in each of the nine regions. These include both copy number increases and decreases. Although the number of regions selected for this first generation array is small, we observed multiple segmental changes. In some cases, we observed single BAC clone alterations at 7p11 and 11q13 which contain EGFR and cyclin D1 respectively highlighting the need for high resolution detection techniques. Array comparative genomic hybridization (CGH) complements traditional methods for detecting genetic alterations in OSCC (such as microsatellite and CGH analysis) by improving the detection of segmental copy number alterations to single BAC clone resolution. This work represents the first attempt at the construction of an oral cancer-specific CGH array.

The prognostic value of epidermal growth factor receptor is related to tumor differentiation and the overall treatment time of radiotherapy in squamous cell carcinomas of the head and neck

Accelerated repopulation in head-and-neck carcinomas might be related to the expression of proliferative factors such as epidermal growth factor receptor (EGFr). The present study focuses on the prognostic value of EGFr for T-site control and the relation to tumor cell differentiation and overall treatment time. We studied 336 patients treated with primary radiotherapy using 66-68 Gy, 2 Gy per fraction and overall treatment times of 912, 612, or 512 weeks. Pretreatment biopsies were stained for EGFr.Thirty-five percent of the carcinomas had less than 50% of the area stained for EGFr. Small T-size and well-differentiated tumors was associated with a high degree of staining (p = 0.001 and p = 0.002, respectively). EGFr was of poor prognostic influence regarding local control in patients treated with 9 weeks split-course, whereas the opposite was found for patients given accelerated treatment in 5 weeks. A similar relationship between outcome, overall treatment time, and differentiation has previously been shown. The two parameters were analyzed together by separating the tumors with low EGFr and/or poor differentiation from tumors with well/moderate differentiation and high EGFr, resulting in odds ratios for T-site failure of 12 (1.43-104), 0.91 (0.51-1.65), and 0.43 (0.17-1.08), for treatment times of 912, 612, and 512 weeks, respectively. The tumor response to variations in fractionation is heterogeneous, and the prognostic impact of EGFr and differentiation might be relative and dependent on the overall treatment time of radiotherapy.