Microsatellite analyses of loci at 7q31.3-q36 reveal a minimum of two common regions of deletion in nasopharyngeal carcinoma

CPVL suppresses metastasis of nasopharyngeal carcinoma through inhibiting epithelial-mesenchymal transition

PURPOSE

Distant metastasis is the main obstacle to treating nasopharyngeal carcinoma (NPC). Tumor distance metastasis is a complex process involving the jointly participation of multiple oncogenes, tumor suppressor genes, and metastasis-associated genes. Enough accurate prognostic genes for evaluating metastasis risk are lacking. We aimed to identify more precise biomarkers for NPC metastasis.

METHODS

We performed weighted gene co-expression network analysis, differentially expressed gene analysis, univariate and multivariate stepwise Cox regression, and Kaplan-Meier (K-M) survival analyses, on data obtained from RNA sequencing of 10 NPC samples and the public database, to identify key genes correlated with NPC metastasis. Wound healing assays, transwell assays, and immunohistochemistry were conducted to validate our bioinformatic conclusions. Western blotting was performed to evaluate and quantify the effect of identified EMT genes on epithelial-mesenchymal transition (EMT) of NPC.

RESULTS

Combined our own RNA sequencing data and public data, we determined carboxypeptidase vitellogenic-like protein (CPVL) as a tumor suppressor for NPC. Pathway enrichment analyses indicated that genes associated with CPVL are involved in EMT. NPC with low CPVL expression had high tumor purity and low levels of immune cells. Experimental results showed that CPVL protein predominantly expressed in cytoplasmic and membranous and it exhibited higher expression levels in NPC tissues without distant metastasis than those with distant metastasis. CPVL inhibits the migration and invasive capability of NPC cells. Overexpression of CPVL upregulates E-cadherin and ZO-1, whereas it downregulates vimentin, suggesting that CPVL suppresses tumor metastasis by inhibiting EMT.

CONCLUSION

CPVL inhibits migration and invasion of NPC cells and is associated with tumor metastasis suppression through upregulating epithelial marker and inhibiting mesenchymal marker expression and could be a prognostic biomarker for metastasis risk evaluation in NPC.

Genomic instability in the progression of sporadic nasopharyngeal carcinoma

OBJECTIVE

Genomic instability reflecting the susceptibility of the genome to acquire multiple genetic alterations plays a major role in tumorigenesis and tumor progression. We evaluated the prognostic significance of the extent of genomic instability in nasopharyngeal carcinoma.

STUDY DESIGN AND SETTING

Genomic instability was assessed by inter-simple sequence repeats polymerase chain reaction (inter-SSR PCR) in 38 patients with nasopharyngeal carcinoma. Characterization and verification of band alterations shared in different tumors were carried out by sequencing and nest PCR.

RESULTS

31 (81.6%) of 38 patients showed genomic alterations, and genomic instability index ranged from 0 to 16.2%. A gain-based genomic damage shared in 6 tumors was identified on chromosome 6q27, a new mutator phenotype in nasopharyngeal carcinoma. Significantly more genomic alteration was found in patients without 5-year survival than that with 5-year survival (P<0.05), suggesting that higher genomic instability predicts a poor prognosis in nasopharyngeal carcinoma.

CONCLUSIONS AND SIGNIFICANCE

Our data suggests that genomic instability can be an early event marker in carcinogenesis of nasopharyngeal carcinoma. Also, aggravation of genomic alterations is a poor prognosis for cancer recovery.

Expression and functional characterization ofLRRC4, a novel brain-specific member of the LRR superfamily

LRRC4, a novel member of LRR superfamily thought to be involved in development and tumorigenesis of the nervous tissue, has the potential to suppress tumorigenesis and cell proliferation of U251MG cells. This study aimed at revealing the correlation between expression of LRRC4 and the maintenance of normal function and tumorigenesis suppression within the central nervous system. We systematically analyzed the expression and tissue distributions of the gene in tissues. Results showed that LRRC4 expression was limited to normal adult brain, both in human and in mouse, and exhibited a development-regulated pattern, but was down-regulated in brain tumor tissues and U251MG cell line. Furthermore, dynamic alterations in gene expression associated with cell cycle progression were investigated by using Tet-on system. Results showed that LRRC4 induced a cell cycle delay at the late G1 phase, probably through the alteration of the expression of different cell cycle regulating proteins responsible for mediating G1-S progression, such as p21(Waf1/Cip1) and p27(Kip1), Cdk2 and PCNA, p-ERK1/2. These findings suggest that LRRC4 may play an important role in maintaining normal function and suppressing tumorigenesis in the central nervous system.