American Association for Cancer Research
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Supplementary Figures 1 through 4 and Supplementary Tables 1 through 3 from Involvement of microRNA-24 and DNA Methylation in Resistance of Nasopharyngeal Carcinoma to Ionizing Radiation

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journal contribution
posted on 2023-04-03, 14:20 authored by Sumei Wang, Rong Zhang, Francois X. Claret, Huiling Yang

Supplementary Figure 1: MiRs are expressed differently in CNE-2 and CNE-2R cells. Supplementary Figure 2: The relative percentage of methylation level between CNE-2 and CNE- 2R by cytosine-extension assay. Supplementary Figure 3: Genomic DNA methylation is altered between CNE-2 and CNE-2R cells. Supplementary Figure 4: MiR-24 promoters's CpG islands distribution. Supplementary Table 1: Information of 6 pairs NPC primary and recurrent patients. Supplementary Table 2: Radioresistant miRs signature between CNE-2 and CNE-2R. Supplementary Table 3: The numbers of genes altered on methylation between CNE-2 and CNE-2R.

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ARTICLE ABSTRACT

Nasopharyngeal carcinoma (NPC) is a malignant tumor originating in the epithelium. Radiotherapy is the standard therapy, but tumor resistance to this treatment reduces the 5-year patient survival rate dramatically. Studies are urgently needed to elucidate the mechanism of NPC radioresistance. Epigenetics—particularly microRNAs (miRNA) and DNA methylation—plays an important role in carcinogenesis and oncotherapy. We used qRT-PCR analysis and identified an miRNA signature from differentially expressed miRNAs. Our objectives were to identify the role of miR24 in NPC tumorigenesis and radioresistance and to identify the mechanisms by which miR24 is regulated. We found that miR24 inhibited NPC cell growth, promoted cell apoptosis, and suppressed the growth of NPC xenografts. We showed that miR24 was significantly downregulated in recurrent NPC tissues. When combined with irradiation, miR24 acted as a radiosensitizer in NPC cells. One of the miR24 precursors was embedded in a CpG island. Aberrant DNA methylation was involved in NPC response to radiotherapy, which linked inactivation of miR24 through hypermethylation of its precursor promoter with NPC radioresistance. Treating NPC cells with the DNA-hypomethylating agent 5-aza-2′-deoxycytidine compensated for the reduced miR24 expression. Together, our findings showed that miR24 was negatively regulated by hypermethylation of its precursor promoter in NPC radioresistance. Our findings defined a central role for miR24 as a tumor-suppressive miRNA in NPC and suggested its use in novel strategies for treatment of this cancer. Mol Cancer Ther; 13(12); 3163–74. ©2014 AACR.