transforming-growth-factor-alpha and Oropharyngeal-Neoplasms

Human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinomas (OSCCs) are two distinct entities. We defined the molecular profiles of druggable receptor tyrosine kinases (RTKs) in both groups.. E5 expression and RTK alterations were studied in 17 HPV-positive and 59 HPV-negative formalin-fixed OSCCs. RTK activation was explored in further 12 frozen OSCCs.. The HPV-positive OSCCs showed E5 expression and 33.3% expressed low level of HER2. The HPV-negative OSCCs showed HER2 expression (31.2%), increased HER2 gene copy number (46.51%, P = 0.045) and HER2 activation through HER2/EGFR heterodimerisation; HER3 (51.06%, P = 0.008) and neuregulin (65.63%; P = 0.03) expression, HER3 activation and HER3/EGFR heterodimerisation; and increased IGF-1R copy number (40.50%, P = 0.021), high IGF-1R cDNA values (P = 0.002), IGF-1R activation and expression of IGF1/2 and amphiregulin. PI3KCA mutations/expression/increased gene copy number and PTEN mutations were found in both groups, whereas PTEN gene loss was only observed in the HPV-positive cases.. Human papillomavirus-positive and HPV-negative OSCC showed different RTK profiles. In HPV-positive cases, it would be interesting to study the expression of E5, which may modulate EGFR turnover and activate VEGF and PDGFRβ. In HPV-negative cases, HER3 may be a promising druggable biomarker that deserves further investigation. PI3KCA and PTEN alterations encourage the promising clinical evaluation of PI3K/mTOR inhibitor activity in OSCC, particularly in HPV-positive/PI3KCA-mutated OSCCs because they may be driven by PI3KCA mutation alone.

Topics: Amphiregulin; Biomarkers, Tumor; Carcinoma, Squamous Cell; Humans; Mouth Neoplasms; Mutation; Oropharyngeal Neoplasms; Papillomaviridae; Papillomavirus Infections; Peptide Fragments; Phosphatidylinositol 3-Kinases; PTEN Phosphohydrolase; Real-Time Polymerase Chain Reaction; Receptor Protein-Tyrosine Kinases; Receptor, ErbB-2; Transforming Growth Factor alpha

About two thirds of head and neck squamous cell carcinoma (HNSCC) cases are attributable to heavy tobacco and alcohol consumption. Tobacco carcinogens cause cellular damage in large areas of the upper aerodigestive tract mucosa and contribute to distinct molecular changes, such as increasing levels of epidermal growth factor receptor (EGFR), during carcinogenesis. P-Glycoprotein (P-GP) is a multidrug-resistance transporter protein capable of extruding not only cytotoxic drugs, but also certain tobacco-related carcinogens. EGFR plays a major role in the transcriptional and functional regulation of P-GP and previous studies in our laboratory showed that stimulation of EGFR protection protected oropharyngeal cells from a carcinogen that is substrate of P-GP. Therefore, we evaluated expression levels of EGFR and P-GP and looked for a possible association with the smoking status of patients.. Tissue cultures of healthy oropharyngeal mucosa were produced from 30 patients undergoing surgery at our Department. Expression levels of EGFR on P-GP were determined by immunohistochemical staining. To evaluate possible influences of EGFR on P-GP expression, we stimulated the receptor using transforming growth factor alpha (TGF-α) for 24, 48 and 72 h.. Current and former smokers had significantly higher EGFR/P-GP levels than never smokers. While EGFR expression was detected in almost all samples, P-GP expression was largely restricted to former and current smokers. TGF-α had no detectable effect on EGFR/P-GP levels.. These results show an association between tobacco use and levels of both proteins. Since both these proteins are involved in drug resistance of head and neck cancer, this study might help to further understand the differences in response to therapy and prognosis of tobacco-related and -unrelated cancer.

Topics: Adolescent; Adult; Aged; ATP Binding Cassette Transporter, Subfamily B, Member 1; Drug Resistance, Neoplasm; ErbB Receptors; Female; Humans; Male; Middle Aged; Mucous Membrane; Oropharyngeal Neoplasms; Oropharynx; Papillomaviridae; Smoking; Transforming Growth Factor alpha

The monoclonal epidermal growth factor receptor (EGFR) antibody cetuximab (Erbitux) was recently approved by the European Medicines Agency for the treatment of recurrent and/or metastatic head and neck squamous cell carcinoma (HNSCC) in combination with a platinum-based chemotherapy. Since the antibody has only a limited effect as a monotherapy, possible explanations for the synergistic effect with cisplatin are enhanced antibody-dependent cytoxicity and increased sensitivity to the drug. Most of our knowledge of EGFR biology in HNSCC is based on studies using EGFR inhibitors and/or antibodies. Our study was designed to evaluate the impact of EGFR stimulation on cisplatin-induced DNA damage. Therefore, tissue cultures were produced of tumor-free oropharyngeal mucosa biopsies of HNSCC patients and controls. In a previous study, overexpression of EGFR in tissue cultures from tumor patients compared to controls was confirmed by immunohistochemical staining. Twenty-four-hour stimulation of tissue cultures with transforming growth factor alpha (TGF-alpha), a specific EGFR ligand, resulted in a reduction of cisplatin-induced DNA damage by 35% in cases, whereas in controls TGF-alpha had no effect. This reflects a statistically significant increase in cellular chemoresistance to cisplatin following TGF-alpha stimulation and helps to further understand effects of EGFR antisense therapy in combination with chemotherapy.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Carcinoma, Squamous Cell; Cetuximab; Cisplatin; DNA Damage; Drug Resistance, Neoplasm; ErbB Receptors; Head and Neck Neoplasms; Humans; Mucous Membrane; Oropharyngeal Neoplasms; Tissue Culture Techniques; Transforming Growth Factor alpha

Epidermal growth factor receptor (EGFR) has been implicated in cellular responses to ionizing radiation and represents a major target for current radiosensitizing strategies. We wished to ascertain whether a correlation existed between the expression of EGFR, transforming growth factor-alpha (TGFalpha) and platelet-derived growth factors A and B (PDGF-A and PDGF-B) and treatment outcome in a group of patients with oropharyngeal cancer who had undergone curative radiation therapy. We also assessed the relationship existing between each of the aforementioned proteins and intratumoral microvessel densities (IMD) which have been previously reported (Int J Radiat Oncol Biol Phys 2000;48:17-25.. Pretherapeutic tumor biopsies from 95 patients were immunohistochemically stained and their immunoreactivities evaluated semi-quantitatively. The statistical analyses included Cox regression for calculating risk ratios of survival endpoints and logistic regression for determining odds ratios for the development of distant metastasis.. Local tumor control as well as disease-free and overall survival were independent of protein expression levels, whereas combined TGFalpha and EGFR immunoreactivities were closely related to IMD (P = 0.003). The expression levels of these two proteins were also correlated to each other (P = 0.015). Expression of PDGF-B occurred in 54% of cases and was associated with an increase in the risk of developing distant metastasis (P = 0.011).. Tumoral levels of TGFalpha, EGFR and PDGF-A/B are not predictive of radioresponsiveness in oropharyngeal cancers. The association between IMD and immunoreactivity for TGFalpha and EGFR indicates the involvement of these proteins in the promotion of angiogenesis in these tumors. PDGF-B should be further evaluated as a prognostic marker for squamous cell cancer of the head and neck.

Topics: Disease-Free Survival; ErbB Receptors; Female; Humans; Male; Middle Aged; Neoplasms, Squamous Cell; Oropharyngeal Neoplasms; Platelet-Derived Growth Factor; Proportional Hazards Models; Transforming Growth Factor alpha

Using immunohistochemistry, expression of p53, transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erbB-2/neu and proliferating cell nuclear antigen (PCNA) was examined in 26 fresh frozen tissue specimens of oropharyngeal squamous cell carcinomas (SCCs). p53 gene mutations were examined by polymerase chain reaction (PCR)/DNA sequencing methods in 22 carcinomas. The findings were examined for correlations with patients' clinicopathological parameters. Expressions of p53 and PCNA were also examined in 21 formalin-fixed corresponding tissues. Of the fresh frozen tissue specimens, 77% (20/26) showed expression and 68% (15/22) showed mutations (substitutions) of the p53, with significant clustering of the mutations in exons 5 (8/22; 36%), 7 (4/22; 18%) and 8 (5/22; 23%). No mutations were found in exon 6. There was a discordance between expression of p53 protein and mutations of the gene. Parallel to expression and mutations of the p53 found in most of the specimens, expression of TGF-alpha, EGFR, c-erbB-2/neu and PCNA was found in 88% (22/25), 92% (23/25), 58% (14/24) and 91% (21/23) of the specimens, respectively. For the formalin-fixed tissue specimens, 62% (13/21) and 90% (19/21) expressed p53 and PCNA, respectively. Examining for correlations with patients' clinicopathological parameters, expression of p53, TGF-alpha, EGFR and c-erB-2/neu seemed to negatively correlate with the increase of the tumour grade. The present work suggests that: (1) lack of negative growth regulation due to inactivation of the p53 gene together with activation of other proto-oncogenes are necessary genetic events in the carcinogenesis of oropharyngeal SCCs; (2) in oropharyngeal SCCs, p53 gene mutations were clustered in exons 5 (codons 130-186), 7 (codons 230-248) and 8 (codons 271-282) which perhaps suggests that tobacco carcinogens probably affect the mutational hot spots of the p53 gene at codons 157, 175, 186, 248, 273 and 282; and (3) fresh frozen and formalin-fixed tissue specimens give similar results when an immunohistochemical method is applied. The importance of p53, TGF-alpha, EGFR, c-erbB-2/neu and PCNA as biomarkers in oropharyngeal SCCs deserves particular attention because it might offer further understanding of the development of these carcinomas.

Topics: Adult; Aged; Aged, 80 and over; Alcohol Drinking; Biomarkers, Tumor; Carcinoma, Squamous Cell; DNA, Neoplasm; ErbB Receptors; Female; Humans; Immunohistochemistry; Male; Middle Aged; Mutation; Oropharyngeal Neoplasms; Polymerase Chain Reaction; Proliferating Cell Nuclear Antigen; Receptor, ErbB-2; Sequence Analysis, DNA; Smoking; Transforming Growth Factor alpha; Tumor Suppressor Protein p53

Eukaryotic translation initiation factor 5A (eIF-5A) is the only cell protein that contains the unusual basic amino acid hypusine [N epsilon-(4-amino-2-hydroxybutyl)lysine]. Hypusine is formed by the transfer of the butylamine portion from spermidine to the epsilon-amino group of a specific lysine residue of eIF-5A precursor and the subsequent hydroxylation at carbon 2 of the incoming 4-aminobutyl moiety. Agents that reduce cell hypusine levels inhibit the growth of mammalian cells. These observations suggest that hypusine is crucial for proliferation and transformation of eukaryotic cells. Here we have studied whether the inhibition of hypusine synthesis can potentiate the anti-cancer activity of the anti-tumour agents interferon-alpha (IFN alpha) and cytosine arabinoside (ara-C). We have found that IFN alpha increased epidermal growth factor receptor (EGF-R) expression, but reduced S phase and proliferative marker expression in human epidermoid KB cells and that this effect was antagonised by epidermal growth factor (EGF). Growth inhibition induced by IFN alpha was paralleled by decreased hypusine synthesis and, when EGF counteracted anti-proliferative effects, a reconstitution of hypusine levels was recorded. We also studied the effects of IFN alpha on the cytotoxicity of the recombinant toxin TP40 which inhibits elongation factor 2, another step of protein synthesis, through EGF-R binding and internalisation; IFN alpha induced an about 27-fold increase of TP40 cytotoxicity in KB cells. Ara-C, another antineoplastic agent commonly used in haematologic malignancies, induced both apoptosis and iron depletion in human acute myeloid leukaemic cells. The combination of ara-C and of the iron chelator desferioxamine, a strong inhibitor of hypusine synthesis, had a synergistic activity on apoptosis in these cells. The data strongly suggest that the post-translational modifications of eIF-5A could be a suitable target for the potentiation of the activity of anti-cancer agents.

Topics: Antineoplastic Agents; Cell Cycle; Cell Death; Chelating Agents; Cytarabine; Deferoxamine; Epidermal Growth Factor; ErbB Receptors; Eukaryotic Translation Initiation Factor 5A; Exotoxins; Humans; Interferon-gamma; Iron; Kinetics; Leukemia; Lysine; Oropharyngeal Neoplasms; Peptide Initiation Factors; Protein Processing, Post-Translational; RNA-Binding Proteins; Transforming Growth Factor alpha; Tumor Cells, Cultured

We previously found that interferon alpha2 recombinant (IFNalpha) increases the expression of epidermal growth factor receptor (EGF-R) in the human epidermoid cancer KB cell line. Here we report the effects of IFNalpha and epidermal growth factor (EGF) on KB cell cycle kinetics. IFNalpha (1000 i.u./ml) for 48 h decreased the S-phase fraction and diminished the expression of Ki67 and proliferating cell nuclear antigen on KB cells. Incubation of IFNalpha-treated KB cells with 10 nM EGF for 12 h reversed these effects. We then studied several biochemical markers of cell proliferation. Ornithine decarboxylase activity was decreased to about one-tenth by IFNalpha and partly restored by EGF. Hypusine is contained only in eukaryotic initiation factor 5A and its levels are correlated with cell proliferation. IFNalpha decreased hypusine synthesis by 75%; exposure of cells to EGF for 12 h restored hypusine synthesis almost completely. We also studied the effects of IFNalpha on the cytotoxicity of the recombinant toxin TP40, which inhibits elongation factor 2 through EGF-R binding and internalization. IFNalpha greatly enhanced the TP40-induced inhibition of protein synthesis in KB cells. In conclusion, IFNalpha, which affects protein synthesis machinery and increases EGF-R expression, enhances the tumoricidal activity of TP40 and hence could be useful in the setting of anti-cancer therapy.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Epidermal Growth Factor; Exotoxins; Humans; Interferon alpha-2; Interferon-alpha; Lysine; Ornithine Decarboxylase; Oropharyngeal Neoplasms; Recombinant Proteins; Transforming Growth Factor alpha; Tumor Cells, Cultured

Previous studies have shown increasing evidence that TGF-alpha, a ligand for the often overexpressed EGF-receptor may be important for the oncogenesis and autocrine stimulation of the proliferation in head and neck cancers. The occurrence of TGF-alpha and its relation to the EGF-receptor still remain unclear. Twenty six specimens (primaries and metastasis) of oropharyngeal squamous cell carcinomas were investigated for the presence of transforming growth factor alpha (TGF-alpha), epidermal growth factor (EGF) and the EGF-receptor using a tissue extraction method and a "sandwich" immuno absorbent assay. In 77% of the specimens we found TGF-alpha, all had a significant amount of EGF-receptors, no EGF was found. No significant difference was noted for metastasis and primaries. No correlation was seen to the TNM stage and to the histological grading. There was an inverse statistical correlation between the TGF-alpha and the EGF-receptor concentration. High TGF-alpha concentrations were associated with low EGF-receptor concentration. Interestingly, even high TGF-alpha concentrations showed a lower limit of EGF-receptor concentrations which could not be passed. The present investigation gives a quantitative determination of the EGF-receptors and TGF-alpha in oropharyngeal carcinomas. The results indicate that a EGF-receptor/TGF-alpha complex could be functionally important for autocrine/paracrine stimulation.

Topics: Carcinoma; Epidermal Growth Factor; Humans; Oropharyngeal Neoplasms; Oropharynx; Transforming Growth Factor alpha