Epidermal growth factor protects squamous cell carcinoma against cisplatin-induced cytotoxicity through increased interleukin-1β expression

• Published in: PloS one 2013-02, Vol.8 (2), p.e55795
• Main Authors: Ko, Shian-Chin, Huang, Chi-Ruei, Shieh, Jiunn-Min, Yang, Jhen-Hong, Chang, Wen-Chang, Chen, Ben-Kuen
• Format: Article
• Language: English
• Subjects: AKT protein; Apoptosis; Binding sites; Bioinformatics; Biology; Biomarkers; Biomarkers, Tumor - metabolism; Blotting, Western; Cancer; Carcinogenesis; Carcinogens; Carcinoma, Squamous Cell - drug therapy; Carcinoma, Squamous Cell - metabolism; Cell adhesion & migration; Cell death; Chemoresistance; Chromones; Cisplatin; Cisplatin - metabolism; Cisplatin - pharmacology; Cytokines; Cytotoxicity; Cytotoxins - metabolism; Cytotoxins - pharmacology; DNA Primers - genetics; Enzyme-Linked Immunosorbent Assay; Enzymes; Epidermal growth factor; Epidermal Growth Factor - metabolism; Epidermal growth factor receptors; Flow Cytometry; Fluorescent Antibody Technique; Gene expression; Gene Expression Regulation, Neoplastic - physiology; Humans; IL-1β; Immunofluorescence; Inflammation; Inhibition; Interleukin; Interleukin-1beta - metabolism; Interleukins; Kinases; Medicine; Metastasis; Morpholines; mRNA stability; NF-kappa B - metabolism; NF-κB protein; Nuclear transport; Oncogene Protein v-akt - metabolism; Penicillin; Real-Time Polymerase Chain Reaction; Receptor, Epidermal Growth Factor - metabolism; Regulators; RelA protein; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Small Interfering - genetics; Rodents; Sesquiterpenes; Signal transduction; Signal Transduction - genetics; Signal Transduction - physiology; Signaling; Squamous cell carcinoma; Stability; Toxicity; Transcription activation; Translocation
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0055795

The expression of cytokines, such as IL-1β, and the activation of the epidermal growth factor receptor (EGFR) are crucial regulators in the process of carcinogenesis. The correlation between growth factor and activated cytokine signals in the control of tumor development is a critical issue to be clarified. In our study, we found that the IL-1β gene and protein expression were induced by EGF in squamous cell carcinoma. To clarify the mechanism involved in EGF-regulated IL-1β expression, we examined the transcriptional activity and mRNA stability of IL-1β in EGF-treated cells. We found that EGF induced the expression of IL-1β and was mediated through transcriptional activation, but not through mRNA stability. The involvement of Akt and NF-κB signaling pathways in the EGF-induced IL-1β gene expression was confirmed by knockdown of RelA and Akt in cells or treating cells with Akt and NF-κB inhibitors, LY294002 and parthenolide, respectively. The expression of dominant negative IκB also repressed the activation of NF-κB and inhibited EGF-induced IL-1β expression. Using immunofluorescence staining assay, the EGF-stimulated nuclear translocation of NF-κB (p65) was inhibited by pre-treating cells with LY294002 and parthenolide. Furthermore, EGF increased the binding of NF-κB to the NF-κB binding site of the IL-1β promoter through the activation of the Akt/NF-κB pathway, which resulted in activating IL-1β promoter activity. The expression and secretion of IL-1β induced by EGF considerably reduced chemotherapeutic drug cisplatin-induced cell death. These results showed that EGF enhanced the expression of IL-1β, which was mediated by the Akt/NF-κB pathway. The activation of EGF signaling and increase of IL-1β contributed to chemotherapeutic resistance of cancer cells, suggesting that the expression of IL-1β may be used as a biomarker to evaluate successful cancer treatment.