CENPN suppresses autophagy and increases paclitaxel resistance in nasopharyngeal carcinoma cells by inhibiting the CREB-VAMP8 signaling axis.

ABSTRACT

Chemotherapeutic resistance is one of the most common reasons for poor prognosis of patients with nasopharyngeal carcinoma (NPC). We found that CENPN can promote the growth, proliferation and apoptosis resistance of NPC cells, but its relationship with chemotherapeutic resistance in NPC is unclear. Here we verified that the CENPN expression level in NPC patients was positively correlated with the degree of paclitaxel (PTX) resistance and a poor prognosis through analysis of clinical cases. VAMP8 expression was significantly increased after knockdown of CENPN by transcriptome sequencing. We found in cell experiments that CENPN inhibited macroautophagy/autophagy and VAMP8 expression and significantly increased PTX resistance. Overexpression of CENPN reduced the inhibitory effects of PTX on survival, cell proliferation, cell cycle progression and apoptosis resistance in NPC cells by inhibiting autophagy. In turn, knockdown of CENPN can affect the phenotype of NPC cells by increasing autophagy to achieve PTX sensitization. Sequential knockdown of CENPN and VAMP8 reversed the PTX-sensitizing effect of CENPN knockdown alone. Experiments in nude mice confirmed that knockdown of CENPN can increase VAMP8 expression, enhance autophagy and increase the sensitivity of NPC cells to PTX. Mechanistic studies showed that CENPN inhibited the translocation of p-CREB into the nucleus of NPC cells, resulting in the decreased binding of p-CREB to the VAMP8 promoter, thereby inhibiting the transcription of VAMP8. These results demonstrate that CENPN may be a marker for predicting chemotherapeutic efficacy and a potential target for inducing chemosensitization to agents such as PTX.Abbreviations 3-MA 3-methyladenine; ATG5 autophagy related 5; CENPN centromere protein N; CQ chloroquine; CREB cAMP responsive element binding protein; ChIP chromatin immunoprecipitation assay; IC50 half-maximal inhibitory concentration; LAMP2A lysosomal associated membrane protein 2A; MAP1LC3/LC3 microtubule associated protein 1 light chain 3; NPC nasopharyngeal carcinoma; NPG nasopharyngitis; oeCENPN overexpressed CENPN; PTX paclitaxel; RAPA rapamycin; RNA-seq transcriptome sequencing; shCENPN small hairpin RNA expression vector targeting the human CENPN gene; shCENPN-shVAMP8 sequential knockdown targeting the human CENPN gene and VAMP8 gene; shVAMP8 small hairpin RNA expression vector targeting the human VAMP8 gene; TEM transmission electron microscopy; TIR tumor inhibitory rate; VAMP8 vesicle associated membrane protein 8.