The role of Prolactin/Prolactin Receptor polymorphisms and expression in breast cancer susceptibility and outcome

Background

Prolactin (PRL) is a polypeptide hormone secreted by the anterior pituitary to stimulate growth and differentiation of the normal mammary gland. Together with its receptor, prolactin receptor (PRLR) have been shown to play a role in breast cancer. This study aimed to examine the roles of PRL and PRLR polymorphisms and expression in breast cancer risk and aggressiveness in Thai patients.

Methods

PRL (rs3756824 C/G and rs2244502 T/A) and PRLR (rs37364 G/T and rs249537 A/G) polymorphisms were genotyped by real-time PCR and PRLR expression was assessed by immunohistochemistry (IHC) in breast cancer tissues. The correlations between PRL and PRLR polymorphisms and breast cancer susceptibility/aggressiveness as well as the associations between PRLR expression and clinicopathological parameters were determined.

Results

Two hundred and twenty-seven breast cancer patients and 119 matched controls were recruited at the Division of Head Neck and Breast Surgery, Department of Surgery, Faculty of Medicine, Siriraj Hospital, Thailand from 2010–2014. PRL and PRLR polymorphisms were not correlated with breast cancer susceptibility and there was no association between PRLR polymorphisms and PRLR expression. PRLR was frequently overexpressed in breast cancer with positive hormone receptors. High expression of PRLR was significantly related to the presence of axillary nodal metastasis and lymphovascular invasion and showed a trend towards poorer outcome.

Conclusions

There was a correlation between high PRLR expression and aggressive features of breast cancer. PRLR expression might be utilized as a prognostic factor for identification of luminal breast cancer with poorer outcome.

The BRCA1 3'-UTR: 5711+421T/T_5711+1286T/T genotype is a possible breast and ovarian cancer risk factor

BACKGROUND

A significant proportion of familial and early-onset breast and ovarian cancers occur in individuals without coding mutations of BRCA1 and BRCA2.

AIMS

We identified genetic variation at 3'-untranslated region (UTR) of BRCA1 in familial and early-onset breast and ovarian cancer patients both with and without BRCA1/2 mutation in the coding regions (BRCA1/2 pos and BRCA1/2 neg), and verified the possible cancer risk factor of the specific 3'-UTR variation using functional analysis.

METHODS

BRCA1 SNP analysis was screened in 46 patients and 103 unaffected Thais by heteroduplex analysis and DNA sequencing. After chi-square test for the potential cancer association of the specific 3'-UTR genotypes, the functional tests were conducted using several strategies of the luciferase gene expression model.

RESULTS

We document the existence of two 3'-UTR polymorphic sites, the 5711+421(G or T) and the 5711+1286(C or T). Frequency of homozygous genotype 5711+421T/T_5711+1286T/T (or T/T-T/T) in the group of BRCA1/2 neg cancer patients was triple of that seen in unaffected persons and showed a significant cancer association (p = 0.007). Functional analysis of these polymorphic sites using luciferase experiments showed an obvious significant reduction in activity associated with the T allele at both sites.

CONCLUSION

These results suggest that the inheritance of specific 3'-UTR polymorphisms may predispose individuals to early-onset or familial breast or ovarian cancer.

Oral tongue cancer gene expression profiling: Identification of novel potential prognosticators by oligonucleotide microarray analysis

Background

The present study is aimed at identifying potential candidate genes as prognostic markers in human oral tongue squamous cell carcinoma (SCC) by large scale gene expression profiling.

Methods

The gene expression profile of patients (n=37) with oral tongue SCC were analyzed using Affymetrix HG_U95Av2 high-density oligonucleotide arrays. Patients (n=20) from which there were available tumor and matched normal mucosa were grouped into stage (early vs. late) and nodal disease (node positive vs. node negative) subgroups and genes differentially expressed in tumor vs. normal and between the subgroups were identified. Three genes, GLUT3, HSAL2, and PACE4, were selected for their potential biological significance in a larger cohort of 49 patients via quantitative real-time RT-PCR.

Results

Hierarchical clustering analyses failed to show significant segregation of patients. In patients (n=20) with available tumor and matched normal mucosa, 77 genes were found to be differentially expressed (P< 0.05) in the tongue tumor samples compared to their matched normal controls. Among the 45 over-expressed genes, MMP-1 encoding interstitial collagenase showed the highest level of increase (average: 34.18 folds). Using the criterion of two-fold or greater as overexpression, 30.6%, 24.5% and 26.5% of patients showed high levels of GLUT3, HSAL2 and PACE4, respectively. Univariate analyses demonstrated that GLUT3 over-expression correlated with depth of invasion (P<0.0001), tumor size (P=0.024), pathological stage (P=0.009) and recurrence (P=0.038). HSAL2 was positively associated with depth of invasion (P=0.015) and advanced T stage (P=0.047). In survival studies, only GLUT3 showed a prognostic value with disease-free (P=0.049), relapse-free (P=0.002) and overall survival (P=0.003). PACE4 mRNA expression failed to show correlation with any of the relevant parameters.

Conclusion

The characterization of genes identified to be significant predictors of prognosis by oligonucleotide microarray and further validation by real-time RT-PCR offers a powerful strategy for identification of novel targets for prognostication and treatment of oral tongue carcinoma.

SCCRO (DCUN1D1) induces extracellular matrix invasion by activating matrix metalloproteinase 2

PURPOSE

Ectopic expression of squamous cell carcinoma-related oncogene (SCCRO or DCUN1D1) in NIH-3T3 cells induces invasion in vitro and produces highly invasive xenografts in nude mice with a propensity for regional lymphatical metastasis. The aim of this study was to identify the molecular mechanism underlying SCCRO-induced invasion and metastasis.

EXPERIMENTAL DESIGN

The molecular mechanism of SCCRO-mediated effects on matrix metalloproteinase-2 (MMP2) levels and activity were assessed using a combination of cell biological and molecular methods, including real-time PCR, reporter assay, RNA interference, and chromatin immunoprecipitation assay. Tumor specimens from primary upper aerodigestive tract carcinomas (n = 89) were examined for levels of SCCRO, MMP2, MMP9, MT1-MMP, TIMP1, and TIMP2 mRNA by real-time PCR.

RESULTS

Overexpression of SCCRO increases MMP2 levels and activity, which is required for SCCRO-induced invasion. Modified McKay assays reveal that SCCRO does not bind to the MMP2 promoter, suggesting that its transcriptional effects are indirect. Deletion or mutation of the activator protein-2 (AP2) and p53 binding element within the MMP2 promoter abrogates SCCRO-driven activation. Ectopic expression of SCCRO increases AP2 levels and promotes the binding of p53 to the MMP2 promoter. Consistent with these findings, SCCRO and MMP2 are coexpressed (P<0.0001; r(2)=0.58; 95% confidence interval, 0.46-0.69) in primary (upper aerodigestive tract) carcinomas (n=89), and this coexpression is associated with an increased prevalence of regional nodal metastasis (P=0.04; relative risk, 1.53).

CONCLUSIONS

SCCRO-induced invasion involves activation of MMP2 transcription in an AP2- and p53-dependent manner. SCCRO is a potential marker for metastatic progression in affected cancers.

Squamous cell carcinoma related oncogene/DCUN1D1 is highly conserved and activated by amplification in squamous cell carcinomas

Chromosomal amplification at 3q is common to multiple human cancers, but has a specific predilection for squamous cell carcinomas (SCC) of mucosal origin. We identified and characterized a novel oncogene, SCC-related oncogene (SCCRO), which is amplified along the 3q26.3 region in human SCC. Amplification and overexpression of SCCRO in these tumors correlate with poor clinical outcome. The importance of SCCRO amplification in malignant transformation is established by the apoptotic response to short hairpin RNA against SCCRO, exclusively in cancer cell lines carrying SCCRO amplification. The oncogenic potential of SCCRO is underscored by its ability to transform fibroblasts (NIH-3T3 cells) in vitro and in vivo. We show that SCCRO regulates Gli1--a key regulator of the hedgehog (HH) pathway. Collectively, these data suggest that SCCRO is a novel component of the HH signaling pathway involved in the malignant transformation of squamous cell lineage.

Syk tyrosine kinase is linked to cell motility and progression in squamous cell carcinomas of the head and neck

Syk, a non-receptor tyrosine kinase, is an important component of immunoreceptor signaling in hematopoietic cells. It has been implicated in key regulatory pathways including phosphoinositide 3-kinase and phospholipase Cgamma (PLCgamma) activation in B cells and integrin signaling in platelets and bronchial epithelial cells. Recently, potential roles in cancer have been reported. In breast cancers, reduced Syk expression was associated with invasion, and its overexpression in cell lines was shown to inhibit cell motility. In contrast, Syk has been shown to mediate chemomigration in nasopharyngeal carcinoma cells. Its role in squamous cell carcinomas of the head and neck (SCCHN) has not yet been investigated. Syk mRNA and protein expression was detected in 6 of 10 SCCHN cell lines. When Syk was transfected into Syk-negative cells (SIHN-011A), chemomigration was enhanced in vitro and this was associated with activation of PLCgamma1. Conversely, abrogation of Syk activity by pharmacologic inhibition or small interfering RNA in HN6 cells with high levels of endogenous expression inhibited migration, haptotaxis, and engagement with matrix proteins; this was accompanied by decreased levels of phosphorylated AKT. Similar effects were seen in Syk-positive CAL 27 cells but not in Syk-negative SIHN-011A cells. Immunoprecipitation suggested co-association of Syk with epidermal growth factor receptor and GRB-2. Syk expression in SCCHN patient tissues was examined by semiquantitative real-time PCR (n = 45) and immunohistochemistry (n = 38) in two independent cohorts. Higher levels of Syk expression were observed in tumors and lymph node metastases relative to normal tissues. High Syk expression significantly correlated with worse survival and may be of prognostic value in SCCHN due to its potential role in cell migration and invasion.

Antiproliferative effect of Erycibe elliptilimba on human breast cancer cell lines

Erycibe elliptilimba Merr. & Chun., family Convolvulaceae, is a Thai traditional medicine which has long been prescribed for various infectious and malignant diseases. Bio-assays of extracts from Erycibe elliptilimba Merr. & Chun. showed that a fraction (fraction 3) from an methanolic extract had an antiproliferative effect on SKBR3 and MDA-MB435 human breast cancer cells. The ED50 value of Erycibe elliptilimba Merr. & Chun. fraction 3 was 56.07 and 30.61 microg/ml for SKBR3 and MDA-MB435, respectively. After 48 h of exposure, this fraction at a concentration of 100 microg/ml significantly reduced cell proliferation in both cancer cells. In MDA-MB435 cells, cell cycle analysis showed that the herb extract fraction 3 induced the accumulation of cells in G2/M phase, whereas no significant change in cell cycle was detected in SKBR3 cells. The results indicated that the extract fraction 3 could induce cell cycle arrest in some way. However, further investigation is needed to assess the molecular mechanisms mediated anticancer activities of this plant.

A functional polymorphism in the matrix metalloproteinase-1 gene promoter is associated with susceptibility and aggressiveness of head and neck cancer

Matrix metalloproteinases (MMPs) play an important role in several steps of cancer development. A single guanine insertion polymorphism (2G) in the MMP1 promoter sequence at -1,607 creates an Ets binding site and thus results in enhancing transcriptional activity. This study aimed to evaluate the contribution of this 2G polymorphism on susceptibility and aggressiveness of HNSCC. A panel of HNSCC cell lines and peritumoral fibroblasts were examined for the MMP1 genotypes and expression levels. Genomic DNA was extracted from peripheral blood of 300 patients with newly diagnosed HNSCC and from 300 age- and gender-matched cancer-free controls. Genotyping was carried out using a PCR-RFLP assay. The levels of MMP1 mRNA expression were evaluated by the quantitative RT-PCR and a correlation with different genotype was determined. Odds ratio (OR) for cancer risk were calculated using multivariate logistic regression. In addition, a correlation between the 2G/2G genotype and clinicopathological parameters was examined. Eleven out of 18 HNSCC cell lines showed the 2G/2G genotype (61%) and only 1 cell line had the 1G/1G genotype (5.6%). Cell lines with the 2G/2G genotype expressed significantly higher mean MMP1 mRNA level than those with other genotypes. In clinical model, subjects carrying the homozygous 2G/2G genotype had a higher risk of head and neck cancer compared with subjects with other genotypes (adjusted OR: 2.28; 95% CI: 1.58-3.27), controlling for major confounders. A correlation between promoter polymorphisms and the levels of MMP1 expression in cancer tissues was found, and this 2G/2G genotype was correlated with the adverse clinicopathological parameters. Finally, the highest level of MMP1 enhancement was demonstrated in the coculture of tumor cells and peritumoral fibroblasts of 2G homozygotes. These findings suggest that the presence of 2G polymorphism at the MMP1 promoter is associated with the development and progression of HNSCC.

Enhanced nectin-1 expression and herpes oncolytic sensitivity in highly migratory and invasive carcinoma

PURPOSE

Although a variety of malignant tumors are susceptible to therapy with oncolytic herpes simplex viruses, the determinants of tumor sensitivity to these viruses are poorly understood. Nectin-1 is a cell surface adhesion molecule that is a component of intercellular adherens junctions and also functions as a herpes viral receptor. Because highly invasive cells may have decreased intercellular adhesion, we sought to determine if such cells might also have altered availability of cell surface nectin-1 to act as a herpes receptor.

EXPERIMENTAL DESIGN AND RESULTS

A series of squamous cell carcinoma lines of increasing migratory and invasive potential, termed MG1-MG14, were selected by serial passages of murine SCC7 through Matrigel invasion chambers. Available cell surface nectin-1 was enhanced on the MG11 and MG14 cell lines in comparison to SCC7 as measured by cellular ELISA and immunofluorescence microscopy. A replication-competent, oncolytic herpes virus (NV1023) showed an increased ability to enter MG11 and MG14 cells as compared with SCC7 cells. Furthermore, MG11 and MG14 supported increased herpes viral replication and cytotoxicity over SCC7. For all three of the cell lines, viral entry assays revealed that the actively migrating cells were significantly more susceptible to herpes infection than the nonmigrating cells.

CONCLUSIONS

These results show that malignant cells with highly migratory and invasive properties may exhibit increased cell surface nectin-1 availability, which may serve as a herpes viral receptor to enhance the efficacy of herpes oncolytic therapy. This finding has implications regarding patient selection for future clinical trials using these promising therapeutic vectors.

Gene expression profiling allows distinction between primary and metastatic squamous cell carcinomas in the lung

Lung neoplasms commonly develop in patients previously treated for head and neck carcinomas. The derivation of these tumors, either as new primary lung cancers or as metastatic head and neck cancers, is difficult to establish based on clinical or histopathologic criteria since both are squamous cell carcinomas and have identical features under light microscopy. However, this distinction has significant treatment and prognostic implications. Gene expression profiling was performed on a panel of 52 sequentially collected patients with either primary lung (n = 21) or primary head and neck (n = 31) carcinomas using the Affymetrix HG_U95Av2 high-density oligonucleotide microarray. Unsupervised hierarchical clustering with Ward linkage and the Pearson correlation metric was performed. To assess robustness, bootstrap resampling was performed with 1,000 iterations. A t test of the normalized values for each gene was used to determine the genes responsible for segregating head and neck from lung primary carcinomas, and those with the most differential expression were used for later analyses. In the absence of a large "test" set of tumors, we used a supervised leave-one-out cross-validation to test how well we could predict the tumor origin. Once a gene expression profile was established, 12 lung lesions taken from patients with previously treated head and neck cancers were similarly analyzed by gene expression profiling to determine their sites of origin. Unsupervised clustering analysis separated the study cohort into two distinct groups which reliably remained segregated with bootstrap resampling. Group 1 consisted of 30 tongue carcinomas. Group 2 consisted of 21 lung cancers and 1 tongue carcinoma. The clustering was not changed even when normal lung or tongue profiles were subtracted from the corresponding carcinomatous lesions, and a leave-one-out cross-validation showed a 98% correct prediction (see Supplementary Data 1). A minimum set of 500 genes required to distinguish these groups was established. Given the ability to segregate these lesions using molecular profiling, we analyzed the lung tumors of undetermined origin. All cases clearly clustered with either lung or tongue tumor subsets, strongly supporting our hypothesis that this technique could elucidate the tissue of origin of metastatic lesions. Although histologically similar, squamous cell carcinomas have distinct gene expression profiles based on their anatomic sites of origin. Accordingly, the application of gene expression profiling may be useful in identifying the derivation of lung nodules and consequently enhances treatment planning.

Casein Kinase II Alpha Subunit and C1-Inhibitor Are Independent Predictors of Outcome in Patients with Squamous Cell Carcinoma of the Lung

PURPOSE

Gene expression profiling has been shown to be a valuable tool for prognostication and identification of cancer-associated genes in human malignancies. We aimed to identify potential prognostic marker(s) in non-small cell lung cancers using global gene expression profiles.

EXPERIMENTAL DESIGN

Twenty-one previously untreated patients with non-small cell lung cancer were analyzed using the Affymetrix GeneChip high-density oligonucleotide array and comparative genomic hybridization. Identified candidate genes were validated in an independent cohort of 45 patients using quantitative real-time reverse transcription-PCR and Western blot analyses. Follow-up data for these patients was collected and used to assess outcome correlations.

RESULTS

Hierarchical clustering analysis yielded three distinct subgroups based on gene expression profiling. Cluster I consisted of 4 patients with adenocarcinoma and 1 with squamous cell carcinoma (squamous cell carcinoma); clusters II and III consisted of 6 and 10 patients with squamous cell carcinoma, respectively. Outcome analysis was performed on the cluster groups containing solely squamous cell carcinoma, revealing significant differences in disease-specific survival rates. Moreover, patients having a combination of advanced Tumor-Node-Metastasis stage and assigned to the poor prognosis cluster group (cluster II) had significantly poorer outcomes. Comparative genomic hybridization analysis showed recurrent chromosomal losses at 1p, 3p, 17, 19, and 22 and gains/amplifications at 3q, 5p, and 8q, which did not vary significantly between the cluster groups. We internally and externally validated a subset of 11 cluster II (poor prognosis)-specific genes having corresponding chromosomal aberrations identified by comparative genomic hybridization as prognostic markers in an independent cohort of patients with lung squamous cell carcinoma identifying CSNK2A1 and C1-Inh as independent predictors of outcome.

CONCLUSION

CSNK2A1 and C1-Inh are independent predictors of survival in lung squamous cell carcinoma patients and may be useful as prognostic markers.

Signaling pathways required for matrix metalloproteinase-9 induction by betacellulin in head-and-neck squamous carcinoma cells

The mechanisms by which c-erbB-dependent signaling contribute to the invasive potential of HNSCC remain to be fully elucidated. We have previously shown that c-erbB autocrine and/or paracrine stimulation upregulates MMP-9 but has no effect on the related gelatinase, MMP-2. BTC, a major c-erbB ligand, has the ability to efficiently activate all c-erbB receptors and to bind directly to EGFR and c-erbB-4. BTC is commonly expressed in HNSCC cells and exerts the most potent effects in terms of MMP induction relative to other c-erbB ligands so far tested. In the present study, we explored the contribution of major downstream events triggered by BTC/c-erbB receptor signaling to the regulation of MMP-9 and in vitro invasiveness of HNSCC cells. In human HNSCC cell lines, SIHN-006 and Detroit-562, BTC treatment resulted in rapid tyrosine phosphorylation of all c-erbB receptors whereas both endogenous MMP-9 and BTC-stimulated MMP-9 were predominantly mediated via EGFR. BTC induced ERK1/2, JNK/SAPK and Akt phosphorylation with differing kinetics but not p38 kinase. The BTC-dependent activation of JNK and PI3K/Akt pathways occurred predominantly via EGFR, whereas activation of the MEK-1/ERK pathway occurred via all 4 c-erbB receptors, although again predominantly via EGFR. Selective inhibition of ERK/MAPK (by PD98059 or U0126) and PI3K (by LY294002 or wortmannin) led to marked reduction of both basal and BTC-induced MMP-9 activity and invasive ability of HNSCC cells. In contrast, inhibition of p38 kinase with SB203580 produced no such effects. A specific inhibitor of NF-kappa B, BAY 11-7085, also blocked the stimulatory effect of BTC. No remarkable inhibition of MMP-9 and invasion was observed on targeting other cellular activities, such as PKA, PKC and PLC-gamma. Taken together, our data show that BTC induces MMP-9 production and invasion primarily through activation of EGFR, MAPK and PI3K/Akt in HNSCC cells.

Squamous cell carcinoma related oncogene regulates angiogenesis through vascular endothelial growth factor-A

BACKGROUND

Squamous cell carcinoma related oncogene expression (SCCRO) correlates with vascular endothelial growth factor-A expression. This data is validated in human lung tumors and provides a putative pathway for angiogenesis in a subset of squamous cell carcinomas. Squamous cell carcinoma related oncogene is a novel oncogene identified by positional cloning of a recurrent amplification at 3q26.3. It is over-expressed in 39.8% of lung, head and neck, cervical, and ovarian carcinomas. SCCRO imparts an aggressive phenotype to affected cancers, which may be related to increased angiogenesis due to SCCRO expression. Our previous work has demonstrated a link between SCCRO and vascular endothelial growth factor-A (VEGF-A) expression in vitro, suggesting a mechanism for SCCRO-induced angiogenesis. The present study aims to confirm and validate this link between SCCRO and VEGF-A expression in an ex vivo human tumor cohort.

METHODS

Fresh tissue was collected at Memorial Sloan-Kettering Cancer Center from 34 patients undergoing primary resection of lung squamous cell carcinomas. RNA was extracted from this tissue, reverse-transcribed, and real-time polymerase chain reaction (RT-PCR) was carried out using a BioRad iQ iCycler with SYBR green fluorophore. Microvessel counting was performed on the tumor specimens using CD34 immunohistochemistry.

RESULTS

The expression of both SCCRO and VEGF-A mRNA varies widely in both tumor and normal tissue. SCCRO and VEGF-A co-expression was significantly correlated (R(2) = 0.63; P < 0.032). Microvessel counts were not associated with expression of SCCRO or VEGF-A and failed to significantly predict survival. VEGF-A expression in this patient group is a predictor of overall survival (P < 0.032).

CONCLUSIONS

VEGF-A expression correlates with SCCRO expression in these primary human lung squamous cell carcinomas and is a predictor of clinical behavior. This data supports the association of SCRRO and VEGF-A in the induction of angiogenesis.

Tumour thickness predicts cervical nodal metastases and survival in early oral tongue cancer

Squamous cell carcinoma (SCC) of the oral tongue is characterized by a high propensity for cervical nodal metastasis, which affects the probability of regional control and survival. Until now, elective treatment of the clinically negative neck in early lesions (T(1-2)) of the oral tongue cancer remains controversial. This study attempted to identify predictive factor(s) for cervical nodal metastasis and treatment outcomes in patients with early stage SCC of the oral tongue treated primarily by surgery. Fifty patients with previously untreated Stage I/II primary tongue carcinomas with available archival specimens treated at the Royal Marsden Hospital between 1981 and 1998 were reviewed. Clinico-pathological features including age, gender, alcohol and tobacco consumption, tumour location, histological grade, tumour-stromal border, growth pattern, tumour thickness, and clinical stage were evaluated and the correlations with cervical metastases and outcome analysis were determined. The overall occult nodal metastatic rate was 40% (20/50). Tumour thickness exceeding 5 mm was statistically significantly correlated with cervical metastases (P = 0.003; relative risk = 2.429). No statistical correlation was observed between other clinico-pathological parameters and nodal metastasis. With a median follow-up of 98 months, 5-year actuarial overall, disease-specific (DSS), and relapse-free survival were 65.71, 67.77, and 68.18%, respectively. Univariate analysis for DSS showed poorer outcomes for patients with age > 60 years (P = 0.0423) and tumour thickness > 5 mm (P = 0.0067). The effect of tumour thickness was maintained (P = 0.005) on multivariate analysis. The present study indicates that the thickness of primary tumour has a strong predictive value for occult cervical metastasis and poor outcomes in patients with Stage I/II oral tongue SCC. Thus, elective neck treatment (surgery or irradiation) is indicated for tumours exceeding 5 mm thickness.

The role of c-erbB receptors and ligands in head and neck squamous cell carcinoma

c-erbB receptor signalling induces pleiotropic responses and influences several biological functions involved in the pathogenesis and progression of HNSCC. Aberrant expression of multiple c-erbB receptors and ligands is frequently observed in tumour cells. EGFR appears to be a dominant factor controlling the malignant phenotype in HNSCC at least in part via regulation of molecules involved in invasive and angio-/lymphangiogenic processes. Although c-erbB-2 is an orphan receptor, the formation of heterodimer complexes appears to be an important mechanism for inter-receptor activation and synergistic signal transduction. The roles of c-erbB-3 and c-erbB-4 in HNSCC progression are less clear. However, their ability to form heterodimers with other c-erbB family members enhances proliferation and invasion in HNSCC cells. At least two major downstream signalling pathways, MAPK and PI3K, are involved in the transcriptional regulation of proteases and cytokines implicated in invasion and angiogenesis. Studies using clinical specimens confirmed experimental data that co-operative signalling of c-erbB receptors may play a significant role in the pathogenesis of HNSCC. Most therapeutic studies in HNSCC so far have focused on the strategies targeting of EGFR. Due to the complexity of the system both at the receptor and ligand levels and the integrated biological functions of the c-erbB family in HNSCC, the effect of combined c-erbB blockade (or their downstream signalling pathways) on HNSCC progression should be explored.

C-erbB receptors in squamous cell carcinomas of the head and neck: clinical significance and correlation with matrix metalloproteinases and vascular endothelial growth factors

We studied the profile of four c-erbB receptors in head and neck squamous cell carcinomas (HNSCC) and to determine whether their expression was associated with clinicopathological features and key molecules involved in angiogenesis and metastasis. We also assessed the impact of expression on survival. This study included 54 cases of primary HNSCC, of which 27 cases showed lymph node metastasis. The expression of c-erbB receptors, matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) family members was analysed in the same tissue homogenates by semi-quantitative RT-PCR. HNSCC frequently co-expressed multiple c-erbB receptors and showed significant correlations amongst their levels. High expression of epidermal growth factor receptor (EGFR), c-erbB-2 or c-erbB-3 was associated with an infiltrating mode of invasion, nodal metastases and advanced pathological stages. EGFR and c-erbB-2 levels were strongly correlated (P=0.0004-0.029) with the expression of MMP-2, MMP-7, MMP-9, MMP-10, MMP-11, MMP-13, VEGF-A and VEGF-C whereas the levels of c-erbB-3 and B-4 showed a weaker correlation (P=0.049-0.01) with some MMPs and VEGF-C. Only nodal metastasis and EGFR levels were significantly associated with poor outcome in uni- and multi-variate analysis. We conclude that co-operative signalling of all four c-erbB receptors may play a significant role in the pathogenesis of HNSCC. Amongst these, EGFR appears to be the dominant component controlling the invasive and angio-/lymphangiogenic phenotype in HNSCC via upregulation of multiple MMPs and VEGFs.

Expression of vascular endothelial growth factor family members in head and neck squamous cell carcinoma correlates with lymph node metastasis

BACKGROUND

The expression of vascular endothelial growth factor (VEGF)-A isoforms (121, 165, 189, 206), VEGF-B, VEGF-C and VEGF-D in both experimental and clinical models of head and neck squamous cell carcinoma (HNSCC) was determined and correlated with conventional clinicopathologic parameters, with particular reference to cervical nodal metastasis.

METHODS

The mRNA expression of VEGFs in 14 HNSCC cell lines was compared with 4 normal keratinocyte cultures and 10 fibroblast cultures using a semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay. Protein levels were determined by Western blotting and enzyme-linked immunosorbent assay (ELISA). The authors then examined the expression of VEGFs in tissues from 54 patients including histologically normal epithelium (n = 32), early invasive squamous cell carcinomas (SCCs) (n = 23), advanced primary SCCs (n = 31), and lymph node metastases (n = 27).

RESULTS

Increased levels of VEGF-A (all four isoforms) and VEGF-C were found in tumor cell lines compared with normal cells, whereas no differences in VEGF-B levels were found. VEGF-D expression, however, was lower in HNSCC cells. Studies in clinical samples showed highly significant increases in mRNA expression of all four isoforms of VEGF-A and VEGF-C in tumors versus normal epithelium. In contrast, the levels of VEGF-D were significantly decreased in tumors, and VEGF-B expression appeared similar in both normal and malignant tissues. Multivariate analysis demonstrated that an infiltrative mode of invasion and enhanced expression of VEGF-A (isoforms 121 and 165) and VEGF-C had predictive value for the presence of cervical nodal metastases.

CONCLUSIONS

Up-regulation of VEGF-A (two isoforms) and VEGF-C and down-regulation of VEGF-D have been common features in HNSCC. Thus VEGF-A and VEGF-C appeared to play a vital role in the metastatic process of HNSCC.

Expression of vascular endothelial growth factor family members in head and neck squamous cell carcinoma correlates with lymph node metastasis

BACKGROUND

The expression of vascular endothelial growth factor (VEGF)-A isoforms (121, 165, 189, 206), VEGF-B, VEGF-C and VEGF-D in both experimental and clinical models of head and neck squamous cell carcinoma (HNSCC) was determined and correlated with conventional clinicopathologic parameters, with particular reference to cervical nodal metastasis.

METHODS

The mRNA expression of VEGFs in 14 HNSCC cell lines was compared with 4 normal keratinocyte cultures and 10 fibroblast cultures using a semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay. Protein levels were determined by Western blotting and enzyme-linked immunosorbent assay (ELISA). The authors then examined the expression of VEGFs in tissues from 54 patients including histologically normal epithelium (n = 32), early invasive squamous cell carcinomas (SCCs) (n = 23), advanced primary SCCs (n = 31), and lymph node metastases (n = 27).

RESULTS

Increased levels of VEGF-A (all four isoforms) and VEGF-C were found in tumor cell lines compared with normal cells, whereas no differences in VEGF-B levels were found. VEGF-D expression, however, was lower in HNSCC cells. Studies in clinical samples showed highly significant increases in mRNA expression of all four isoforms of VEGF-A and VEGF-C in tumors versus normal epithelium. In contrast, the levels of VEGF-D were significantly decreased in tumors, and VEGF-B expression appeared similar in both normal and malignant tissues. Multivariate analysis demonstrated that an infiltrative mode of invasion and enhanced expression of VEGF-A (isoforms 121 and 165) and VEGF-C had predictive value for the presence of cervical nodal metastases.

CONCLUSIONS

Up-regulation of VEGF-A (two isoforms) and VEGF-C and down-regulation of VEGF-D have been common features in HNSCC. Thus VEGF-A and VEGF-C appeared to play a vital role in the metastatic process of HNSCC.

Vascular endothelial growth factor family members are differentially regulated by c-erbB signaling in head and neck squamous carcinoma cells

Aberrant expression of tyrosine kinases such as c-erbB and EGFR contributes to the progression of head and neck squamous cell carcinomas (HNSCCs). One mechanism may be potentiation of angiogenesis, since upregulation of vascular endothelial growth factor (VEGF) expression by activation of epidermal growth factor receptor (EGFR) and/or c-erbB-2 has been described. Firstly, we demonstrated expression of all 4 members of the VEGF family in a panel of 15 HNSCC cell lines which over-express one or more c-erbB receptors. We then explored the regulatory roles of three major ligands with different selectivity of binding to c-erbB receptors (namely transforming growth factor-alpha (TGF-alpha), betacellulin (BTC) and heregulin-beta1 (HRG-beta1)) on VEGF-A, B, C and D expression in selected HNSCC lines. Using semi-quantitative reverse transcription-PCR, we showed that all three c-erbB ligands up-regulated VEGF-A mRNA (all isoforms) and VEGF-C (BTC max at 1-10 nM; TGF-alpha and HRG-beta1 max at 10-100 nM) but had no effect on VEGF-B. Interestingly, all ligands simultaneously down-regulated the expression of VEGF-D mRNA. A monoclonal antibody (mAb) which blocks EGFR ligand binding (ICR62) down-regulated the basal levels of VEGF-A (all isoforms) and VEGF-C, had no detectable effects on VEGF-B and increased VEGF-D. ICR62 also reversed the effects of all three erbB ligands (TGF-alpha, BTC and HRG-beta1) on VEGF-A, VEGF-C and VEGF-D expression. An anti-c-erbB-2 mAb (ICR12) showed similar effects on basal or ligand-modulated expression of VEGF in these cell lines, although to a lesser extent. Our results reveal that the four VEGF genes are regulated by c-erbB signaling pathways in a strikingly different manner, suggesting that they serve distinct, although perhaps complimentary (VEGF-A and VEGF-C) or antagonistic (VEGF-D) functions. The EGFR and c-erbB-2 signaling pathway(s) plays a role in VEGF regulation in HNSCC, although EGFR would appear to be dominant in this cell type.

Differential modulation of proliferation, matrix metalloproteinase expression and invasion of human head and neck squamous carcinoma cells by c-erbB ligands

Evidence suggests that there is an association between the abnormal expression of members of the c-erbB receptor tyrosine kinase family and poor prognosis in head and neck squamous cell carcinomas (HNSCC). Until now, the relative contributions of different c-erbB ligands to HNSCC progression have not been clearly defined. In this paper we examined the effects of ligands with different c-erbB receptor specificities in terms of their stimulation of HNSCC proliferation, expression of matrix metalloproteinases (MMPs) and invasion. Heregulin-beta1 (HRG-beta1; selective c-erbB3/B4 ligand) was found to stimulate proliferation in the majority of cell lines, whereas epidermal growth factor (EGF; EGFR ligand) and betacellulin (BTC; EGFR/B4 ligand) induced variable responses. All three ligands up-regulated multiple MMPs including collagenases, stromelysins, matrilysin and gelatinase B (MMP-9) but had minimal or no effects on gelatinase A (MMP-2), MT1-MMP and tissue inhibitors of MMPs (TIMPs). MMP-9 mRNA was induced to a higher level than other MMPs, although with slower kinetics. HRG-beta1 was less active than EGF and BTC at the optimal concentration (relative potency of EGF:BTC:HRG = 3:4:1). In vitro invasion through Matrigel was also increased by all three ligands in proportion to their MMP up-regulation. A specific anti-EGFR monoclonal antibody (mAb ICR62) inhibited MMP up-regulation, migration and invasion induced by all three ligands, whereas an anti-c-erbB-2 mAb ICR12 inhibited mitogenic and motogenic responses following ligand stimulation but had no effect on MMP expression. These results suggest that c-erbB ligands may differentially potentiate the invasive phenotype of HNSCC via co-operative induction of cell proliferation, migration and proteolysis. The EGFR signalling pathway appears to be the dominant component controlling the proteolytic and invasive phenotype in HNSCC, whereas the c-erbB-2 signalling pathway is responsible, in part, for the mitogenic and motogenic effects of ligands.

Epidermal growth factor-like ligands differentially up-regulate matrix metalloproteinase 9 in head and neck squamous carcinoma cells

Head and neck squamous cell carcinomas (HNSCCs) are characterized by a marked propensity for local invasion and dissemination to cervical lymph nodes, with distant metastases developing in 30-40% of cases. Overexpression of the epidermal growth factor receptor (EGFR/c-erbB-1) and/or its ligands and high levels of certain matrix metalloproteinases (MMPs) have been associated with poor prognosis. The aim of this study was to examine the effects of EGFR ligands on gelatinase expression and invasion in HNSCC cell lines. We tested epidermal growth factor (EGF), transforming growth factor alpha, betacellulin, heparin-binding EGF, and amphiregulin and measured expression of gelatinases MMP-9 and MMP-2 in an established squamous carcinoma cell line (Detroit-562) and in two cell lines newly derived from patients with head and neck cancers (SIHN-005A and SIHN-006). Incubation of the cell lines with EGF-like ligands up-regulated MMP-9 (but not MMP-2) expression as measured by semiquantitative reverse transcription-PCR in a dose-dependent manner, with the effects being most marked in cells with high EGFR levels and undetectable in cells with low levels. Maximum stimulation was obtained in a concentration range of 10-100 nM. In addition, we confirmed by zymography that gelatinolytic activity consistent with MMP-9 (Mr 92,000) was up-regulated in parallel with increases in gene expression. Betacellulin (which binds both to EGFR and c-erbB-4 receptors) consistently increased MMP-9 expression and activation to a significantly greater degree than the other four ligands when tested at equimolar concentrations. In parallel with MMP-9 up-regulation, all EGF-like ligands increased tumor cell invasion through Matrigel in in vitro Transwell assays. These activities were independent of ligand effects on cell proliferation. Antagonist (ICR62) or agonist (ICR9) anti-EGFR monoclonal antibodies, respectively, inhibited or potentiated MMP-9 activity and tumor cell invasion induced by all ligands. Furthermore, a monoclonal antibody that neutralizes MMP-9 activity (Abl) also inhibited ligand-induced invasion of HNSCC. We confirmed that tumor cell lines used in these studies (and a larger series not reported here) generally expressed multiple c-erbB receptors and ligands. These results indicate that autocrine or paracrine signaling through EGFR potentiates the invasive potential of HNSCC via the selective up-regulation and activation of MMP-9. Furthermore, ligands such as betacellulin (which is commonly expressed in HNSCC), which can bind to and activate other c-erbB receptors, may be especially potent in this regard.