Low Expression of BIRC5-206 Promotes Cancer Progression in Nasopharyngeal Carcinoma via Enhancing Expression of Stem Cell Markers.

Objective: Survivin is highly expressed in various malignant tumor cells and positively related to poor prognosis and drug resistance. This study aimed to explore the role of non-coding splice variant of Survivin, BIRC5-206 (ENST00000589892.1) in the progression of nasopharyngeal carcinoma (NPC), a malignant tumor that highly occurs in the southern region of China.

Methods: shRNA was used to knockdown BIRC5-206 mRNA level in CNE-2 and HOPNE-1 cells. Then, cell death, migration, invasion and clone formation ability of CNE-2 and HOPNE-1 cells were detected by flow cytometry, scratch-healing experiments, transwell invasion assay and clone formation assay, respectively. CD44+ and CD133+ positive cells were determined via Flow cytometry. Oct4, Nanog and SOX2 protein levels in CNE-2 and HOPNE-1 cells were measured by Western blot.

Results: BIRC5-206 decreased significantly in NPC cell lines. Silencing of BIRC5-206 suppressed the apoptosis, facilitated the migration, invasion and proliferation of both HONE1 and CNE-2 cells. In addition, knockdown of BIRC5-206 significantly promoted the expression cancer stem cell marker (CD44 and CD133) and pluripotency markers (Oct4, Sox2 and Nanog).

Conclusions: BIRC5-206 might facilitate NPC tumor progression by inducing the transformation of NPC cells to cancer stem cells.