Abstract | BACKGROUND: METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to measure the expression levels of PVT1, microRNA (miR)-515-5p and phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) in NPC tissues and cells. Cell counting kit-8 (CCK8) assay, colony formation assay and flow cytometry assay were employed to detect cell proliferation, radiosensitivity and apoptosis, respectively. The protein levels of Cyclin D1, B-cell lymphoma 2 associated X (Bax), Cleaved-caspase-3, PIK3CA, protein kinase B (AKT) and phosphorylated AKT (p-AKT) in samples were measured by Western blot. The starBase was used to predict the binding sites between miR-515-5p and PVT1 or PIK3CA. Dual- luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to verify the interaction. Xenograft tumor model was established to investigate the biological role of PVT1 in vivo. RESULTS: The levels of PVT1 and PIK3CA were upregulated in NPC tissues and cells, opposite to the expression of miR-515-5p. Knockdown of PVT1 inhibited cell proliferation, radioresistance and promoted cell apoptosis in NPC cells. Meanwhile, PVT1 silencing downregulated Cyclin D1, and upregulated Bax and Cleaved-casp-3 in NPC cells after radiotherapy. Besides, miR-515-5p interacted with PVT1 and targeted PIK3CA in NPC cells. Further studies indicated that PVT1 regulated radioresistance via miR-515-5p/PIK3CA axis and modulated the AKT pathway by interacting with miR-515-5p. Moreover, knockdown of PVT1 suppressed tumor growth in vivo. CONCLUSION: Downregulation of PVT1 inhibited proliferation, radioresistance and promoted apoptosis by downregulating PIK3CA via sponging miR-515-5p in NPC cells.
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Authors | Yanyan Han, Fang Li, Jun Xie, Yi Wang, Hua Zhang |
Journal | Cancer management and research
(Cancer Manag Res)
Vol. 12
Pg. 10077-10090
( 2020)
ISSN: 1179-1322 [Print] New Zealand |
PMID | 33116864
(Publication Type: Journal Article)
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Copyright | © 2020 Han et al. |