N6 -Methyladenosine-Modified CBX1 Regulates Nasopharyngeal Carcinoma Progression Through Heterochromatin Formation and STAT1 Activation.

Epitranscriptomic remodeling such as N6 -methyladenosine (m6 A) modification plays a critical role in tumor development. However, little is known about the underlying mechanisms connecting m6 A modification and nasopharyngeal carcinoma (NPC) progression. Here, CBX1 is identified, a histone methylation regulator, to be significantly upregulated with m6 A hypomethylation in metastatic NPC tissues. The m6 A-modified CBX1 mRNA transcript is recognized and destabilized by the m6 A reader YTHDF3. Furthermore, it is revealed that CBX1 promotes NPC cell migration, invasion, and proliferation through transcriptional repression of MAP7 via H3K9me3-mediated heterochromatin formation. In addition to its oncogenic effect, CBX1 can facilitate immune evasion through IFN-γ-STAT1 signaling-mediated PD-L1 upregulation. Clinically, CBX1 serves as an independent predictor for unfavorable prognosis in NPC patients. The results reveal a crosstalk between epitranscriptomic and epigenetic regulation in NPC progression, and shed light on the functions of CBX1 in tumorigenesis and immunomodulation, which may provide an appealing therapeutic target in NPC.

WIPI-1 inhibits metastasis and tumour growth via the WIPI-1-TRIM21 axis and MYC regulation in nasopharyngeal carcinoma.

The metastatic rate of nasopharyngeal carcinoma (NPC) is the highest among head and neck tumours. Additionally, distant metastasis is the main cause of therapy failure and mortality in NPC. Thus, novel biomarkers are needed for designing new therapeutic strategies to improve the prognosis of this disease. In this study, qRT-PCR and western blotting revealed that the expression of the WD repeat domain phosphoinositide interacting 1 (WIPI-1) was markedly decreased in NPC cells and tissues. Furthermore, low WIPI-1 expression closely correlated with poor prognosis in NPC patients. In vitro functional experiments revealed that overexpression or knockdown of WIPI-1 repressed or facilitated the migration, colony formation, and proliferation of NPC cells. Consistent with the in vitro studies, WIPI-1 significantly inhibited tumour growth, invasion and metastasis in popliteal lymph node metastasis, lung metastasis, and xenograft mouse models in vivo. Mechanistically, WIPI-1 directly interacted with tripartite motif containing 21 (TRIM21) and enhanced starvation-induced autophagy by interacting with TRIM21 in NPC cells. Moreover, MYC gene expression was markedly increased in the WIPI-1 knockdown group, as demonstrated by RNA-seq analysis and qRT-PCR validation. Altogether, WIPI-1 acts as a tumour suppressor gene in NPC that inhibits tumour growth and metastasis. Targeting WIPI-1 may be a novel treatment approach for NPC.