| Research Background: Nasopharyngeal carcinoma（NPC）is a severe malignancy arising from the nasopharyngeal epithelium.In 2020,there were 19.3 million new cases and 10.0 million cancer deaths worldwide,of which new cases of nasopharyngeal carcinoma accounted for 0.7% and deaths accounted for 0.8%.Undifferentiated non-keratinizing carcinoma is common in nasopharyngeal carcinoma pathology,with high degree of malignancy and easy to invade adjacent tissues.Radiotherapy and chemotherapy are the most important treatment methods for nasopharyngeal carcinoma.After radical radiotherapy and chemotherapy,some patients still have distant metastasis.The clinical symptoms of nasopharyngeal carcinoma are not obvious,and the anatomical site is relatively hidden and easy to metastasize,so the treatment effect is not ideal.About 70% of newly diagnosed nasopharyngeal cancer patients are in the advanced stage.One of the important reasons for the death of nasopharyngeal cancer is that patients in the advanced stage are more prone to radiotherapy resistance,which leads to the failure of radiotherapy.miRNAs,which have received extensive attention in the past decades,are a class of highly conserved non-coding RNA（nc RNA）molecules with a length of about 22 nucleotides.miRNAs are also post-transcriptional regulators that specifically bind to the 3-untranslated region（3’-UTR）of target m RNAs,resulting in inhibition of translation.Because miRNAs can act in combination with different m RNAs,they can play important regulatory roles in various physiological and developmental processes.miRNA-mediated regulation of gene expression is critical for cellular responses to environmental changes such as hypoxia,oxidative stress,and DNA damage,and is therefore closely related to human diseases such as cancer.miR-149 is one of miRNAs,which plays an important role in the growth,proliferation,invasion and metastasis of tumor cells.Our previous studies showed that miR-149 was highly expressed in nasopharyngeal carcinoma cell lines compared with normal nasopharyngeal epithelial cells.In order to explore the effect of miR-149 on cell growth,proliferation and radiobiological behavior,this study intends to detect the effect of miR-149 on the biological function of nasopharyngeal carcinoma cells through functional experiments such as growth and proliferation,clone formation and wound healing test,and further explore the signal pathways promoting the growth and proliferation of nasopharyngeal carcinoma and inhibiting radiotherapy sensitivity through Western blot.Research method: In CNE2 and SUNE1 cell lines of nasopharyngeal carcinoma,the experiment was carried out in control group and miR-149 overexpression group.The effects of miR-149 overexpression on the growth,proliferation and radiotherapy sensitivity of nasopharyngeal carcinoma cells were detected by functional experiments such as growth,proliferation,clone formation,wound healing test.Research result:1.Compared with normal nasopharyngeal epithelial cells,miR-149 is highly expressed in nasopharyngeal carcinoma tissues.2.In CNE2 and SUNE1 nasopharyngeal carcinoma cells,the high expression of miR-149 was found to promote the growth,proliferation and migration ability and inhibit the radiosensitivity of nasopharyngeal carcinoma cells.3.In CNE2 and SUNE1 nasopharyngeal carcinoma cells,Western blot experiment verified that overexpression of miR-149 may play a role in nasopharyngeal carcinoma through PI3 K / ATK signaling pathway.4.In CNE2 and SUNE1 nasopharyngeal carcinoma cells,Western blot experiment verified that overexpression of miR-149 may be related with the growth and proliferation of nasopharyngeal carcinoma through β-catenin signaling pathway and its downstream target gene.Conclusion: Our study found that miR-149 is highly expressed in nasopharyngeal carcinoma.High expression of miR-149 may promote the growth and proliferation of nasopharyngeal carcinoma,and inhabitat the radiosensitivity of nasopharyngeal carcinoma through PI3K/AKT and β-catenin signaling pathways. |
