MicroRNA-17-5p regulated apoptosis-related protein expression and radiosensitivity in oral squamous cell carcinoma caused by betel nut chewing.

Szu-Yuan Wu,Shing-Hwa Liu,Alexander T.H Wu

doi:10.18632/oncotarget.9856

Abstract

Betel nut chewing is associated with oral cavity cancer. Radiotherapy is one of the therapeutic approaches. Here, we used miR-17-5p antisense oligonucleotides (AS-ODNs) and human apoptosis protein array to clarify which apoptosis-related proteins are increased or decreased by miR-17-5p in betel nut chewing- oral squamous cell carcinoma OC3 cells. Furthermore, miR-17-5p AS-ODN was used to evaluate the radio-sensitization effects both in vitro and in vivo. An OC3 xenograft tumor model in severe combined immunodeficiency mice was used to determine the effect of miR-17-5p AS ODN on tumor irradiation. We simultaneously detected the relative expressions of 35 apoptosis-related proteins in irradiated OC3 cells that were treated with miR-17-5p AS-ODN or a control ODN. Several proteins, including p21, p53, TNF RI, FADD, cIAP-1, HIF-1α, and TRAIL R1, were found to be up- or downregulated by miR-17-5p in OC3 cells; their expression patterns were also confirmed by Western blotting. We further clarified the role of p53 in irradiated OC3 cells, using a p53 overexpression strategy. The results revealed that the enhancement of p53 expression significantly enhanced radiation-induced G2/M arrest of the OC3 cells. In the in vivo study, treatment of miR-17-5p AS-ODN before irradiation significantly enhanced p53 expression and reduced tumor growth. These results suggest that miR-17-5p increases or decreases apoptosis-related proteins in irradiated OC3 cells; its effect on p53 protein expression contributes to the modulation of the radiosensitivity of the OC3 cells.

Highlights

Head and neck cancer is the sixth most common cancer worldwide, with approximately 650000 cases and 200000 deaths annually
Images of the apoptosis array (Figure 1) revealed that apoptosis-related proteins, namely p21, p53, tumor necrosis factor receptor I (TNF RI), Fasassociated death domain protein (FADD), cellular inhibitor of apoptosis protein 1 (cIAP-1), hypoxia-inducible factor (HIF)-1α, and TRAIL R1, exhibited different expression levels in the irradiated oral carcinoma 3 (OC3) cells pretreated with miR-17-5p AS ODN and the cells treated with control ODN (Figure 1B)
These results indicated that miR-17-5p increased or decreased apoptosis-related proteins, namely p21, p53, TNF RI, FADD, cIAP-1, HIF-1α, and TRAIL R1 in the OC3 cells

Summary

Introduction

Head and neck cancer is the sixth most common cancer worldwide, with approximately 650000 cases and 200000 deaths annually. In the United States, approximately 54000 new head and neck cancer cases are annually diagnosed [1]. In certain Asian countries, such as Taiwan, head and neck cancer is the fourth leading cause of cancer deaths and the sixth most common cancer [2]. In Taiwan, more than 99% of head and neck cancers are squamous cell carcinomas, and more than 88% of patients with head and neck cancer have a betel nut-chewing habit [3, 4]. Betel nut chewers have higher incidences of local recurrence, distant metastasis, and secondary primary cancers as well as poorer disease-specific and overall survival than do non-chewers [3].

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Results

Conclusion