LncRNA HOTAIR regulates the expression of E-cadherin to affect nasopharyngeal carcinoma progression by recruiting histone methylase EZH2 to mediate H3K27 trimethylation.

BACKGROUND/AIM: There has been increasing evidence for the function of long non-coding RNA (lncRNA) in nasopharyngeal carcinoma (NPC). We aim to delve into the position of lncRNA HOX antisense intergenic RNA (HOTAIR), together with enhancer of zeste homolog 2 (EZH2), E-cadherin and trimethylation of lysine 27 on histone H3 (H3K27me3) in NPC. METHODS: HOTAIR, EZH2, and E-cadherin expression in NPC tissues and cells were tested. NPC cell biological functions were examined through gain-of and loss-of function assays. The mechanism of lncRNA HOTAIR/E-cadherin/EZH2/H3K27 axis in NPC was decoded. RESULTS: LncRNA HOTAIR and EZH2 were highly expressed in NPC, and E-cadherin was lowly expressed. Down-regulation of HOTAIR or EZH2 inhibited NPC cell progression and tumor growth. HOTAIR recruited histone methylase EZH2 to mediate trimethylation of H3K27 and regulated E-cadherin expression. CONCLUSION: HOTAIR inhibits E-cadherin by stimulating the trimethylation of H3K27 to promote NPC cell progression through recruiting histone methylase EZH2.

Recognition of PDL1/L2 by different induced-fit mechanisms of PD1: a comparative study of molecular dynamics simulations.

Recent clinical data has shown that some cancers choose to express PDL2 compared to PDL1. Therefore, a detailed and comparative study of the dynamic binding mechanism between PD1/PDL1 and PD1/PDL2 can guide drug design towards PD1. Herein, long time-scale classical molecular dynamics simulation, binding free energy calculation, energy decomposition and homology modeling for PD1/PDL2 were used to shed light on the differences in the binding mechanisms of the PD1/PDL1 and PD1/PDL2 complexes. On one hand, our results reveal a different binding mechanism of PD1 binding to PDL1 and PDL2, which is mainly attributed to the induced-fit from different proteins, that is, the C'D loop of PD1 is essential for PD1/PDL1, while the CD loop of PDL2 is critical for PD1/PDL2. Particularly, the "enclosed" conformation of PDL2 leads to a higher affinity between PD1-PDL2 in comparison to the affinity between PD1-PDL1. For PD1/PDL1, the key residues of N66, Y68, Q75, T76, K78, D85, I126, L128, A132, I134 and E136 are the dominant residues for stabilizing the protein-protein interaction (PPI). For PD1/PDL2, the key residues are mainly concentrated in the FG loop, including N33/Q75/L128/A132/Q133/I134/K135. These findings provide a comprehensive understanding of the distinctive binding kinetics and thermodynamic features, which will contribute meaningfully for the design of peptides and small molecule inhibitors to selectively break the PPI interfaces of PD1/PDL1 and PD1/PDL2.

Impact of RTN4 gene polymorphism and its plasma level on susceptibility to nasopharyngeal carcinoma: A case-control study.

The RTN4 gene plays a role in the development and progression of cancer. This case-control study aimed to investigate the association between the RTN4 gene polymorphism and its plasma level with the risk of nasopharyngeal carcinoma (NPC) in a Chinese population.RTN4 gene polymorphisms (rs2920891, rs17046583, rs117465650, rs10496040, and rs2588519) in 220 patients with NPC and 300 healthy controls were analyzed using Snapshot single-nucleotide polymorphism genotyping assays. The plasma level of RTN4 was measured using the enzyme-linked immunosorbent assay.The allele frequencies of RTN4 gene polymorphisms showed no significant difference between the patients and controls (P > .05). Nevertheless, the rs2920891 polymorphism in a dominant model (A/C+C/C) and codominant model (A/C) was significantly associated with the susceptibility to NPC (P = .017, odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.08-2.21 and P = .034, OR = 1.64, 95% CI = 1.13-2.38, respectively). The plasma level of RTN4 was significantly higher in patients with NPC in comparison with the controls (P < .001). Furthermore, we observed that patients with NPC carrying the rs2920891 A/C+C/C genotype had a higher RTN4 level than those carrying the A/A genotype (P < .001).Our findings indicated that the rs2920891 polymorphism may be associated with increased susceptibility to NPC, possibly by increasing plasma RTN4.

Genetic association of promoter in GRP78 gene with nasopharyngeal carcinoma in a Chinese population.

BACKGROUND: Emerging evidences were accumulated to support the view that GRP78 might be associated with multiple types of cancer. Given these, the aim of this study is to investigate the relationship between single nucleotide polymorphisms (SNPs) of GRP78 gene promoter and nasopharyngeal carcinoma (NPC). METHODS: Three SNPs (rs3216733, rs17840761 and rs17840762) in GRR78 promoter were estimated in 422 NPC patients and 452 controls. Genotyping was performed using SNaPshot SNP. Serum GRP78 level was performed by enzyme-linked immunosorbent assay (ELISA). Data were analyzed by SPSS 17.0 software. RESULTS: Significant association between rs3216733 polymorphism and NPC was observed (Cd vs. dd: OR = 0.57, 95% CI 0.43-0.76, P < 0.001; CC vs. dd: OR = 0.62, 95% CI 0.39-0.98, P = 0.043; Cd/CC vs. dd: OR = 0.58, 95% CI 0.44-0.76, P < 0.001; C vs. d OR = 0.70, 95% CI 0.57-0.86, P = 0.001). Additionally, we further found that expression were down-regulated in serum of patients with NPC carrying rs3216733 CC genotype when compared to that of dd genotype (P < 0.001). CONCLUSION: The observations suggest that rs3216733 polymorphism in the GRP78 gene promoter may correlate with NPC susceptibility.

Genetic polymorphisms in interleukin 13 gene with the susceptibility to nasopharyngeal carcinoma in a Chinese population.

Although inflammation is emerging as a candidate risk factor in tumorigenesis of nasopharyngeal carcinoma (NPC). In particular, Interleukin (IL) 13 involved inflammatory diseases and cancers. Single nucleotide polymorphisms in IL-13 have been associated with multiple cancers. The study analyzed genetic polymorphisms in IL-13 aiming to investigate its' potential susceptibility with the NPC. The genotyping of polymorphisms (rs20541, rs1295687 and rs2069744) was examined by Snapshot SNP and DNA sequencing. All SNPs were within Hardy-Weinberg equilibrium and each appeared in three genotypes in NPC and controls. Adjusted logistic regression showed that the TT genotype of rs20541 increased the risk of lymph node metastasis (TT vs. CC: OR = 2.87, 95%CI, 1.33-6.18, P = 0.007). CT/CC genotypes were associated with the decreased the risk of lymph node metastasis in NPC (CT/CC vs. TT: OR = 0.32, 95%CI, 0.16-0.65, P = 0.002). The concentration of IL-13 was significantly elevated in NPC patients compared with controls (P = 0.012). Moreover, significant differences were detected in the T-C-T haplotype distribution between NPC patients and controls (OR = 2.47, 95%CI, 1.06-5.78, P = 0.031). Our results, the first report, provide evidence that rs20541 polymorphisms may affect the lymph node metastasis of NPC patients in Chinese population.

Lycium barbarum polysaccharide prevents cisplatin-induced MLTC-1 cell apoptosis and autophagy via regulating endoplasmic reticulum stress pathway.

BACKGROUND: Lycium barbarum polysaccharide (LBP) has been reported to contribute to the recovery of male hypogonadism and infertility. AIM: The aim of current study was to investigate the underlying mechanisms of LBP on male infertility recovery. METHODS: Recently, it is reported that cell apoptosis mediated by endoplasmic reticulum stress (ERS) was distinguished from that mediated by death reporters and mitochondria pathway, which could induce cell apoptosis independently. The possible signaling mechanisms were investigated using diversified molecular biology techniques, such as flow cytometry, western blotting, and immunofluorescence. RESULTS: In this study, we found that LBP protected Leydig MLTC-1 cells against cisplatin (DDP) by regulating ERS-mediated signal pathway, which was evidenced by downregulation of phosphorylation PERK, phosphorylation of eukaryotic translation-initiation factor 2α and activating transcription factor 4. Meanwhile, LBP decreased DDP-induced MLTC-1 cell apoptosis via reducing ERS apoptosis-relative proteins caspase 3, caspase 7, and caspase 12. In addition, the result of monodansylcadaverine staining indicated that LBP significantly inhibited DDP-induced autophagosome formation in MLTC-1 cells. Moreover, immunofluorescences and Western blot assays demonstrated that LBP reversed DDP-induced LC3II and Atg5 upregulation in MLTC-1 cells. Finally, the data of enzyme-linked immunosorbent assay showed that LBP markedly recovered MLTC-1 cells testosterone level even in the presence of DDP. CONCLUSION: Thus, we suggest that LBP protected MLTC-1 cells against DDP via regulation of ERS-mediated apoptosis and autophagy.

Overexpression of osteopontin promotes cell proliferation and migration in human nasopharyngeal carcinoma and is associated with poor prognosis.

Nasopharyngeal carcinoma (NPC), a malignant tumor at the top and side of the nasopharyngeal cavity, highly occurs in the southern region of China. Cancer cell metastasis is one of the leading causes of death in NPC patients. Osteopontin (OPN), is a phosphorylated extracellular matrix protein with a variety of functions, was found to be overexpressed in many cancers. However, the expression and role of OPN in patients with NPC in Guangxi, China are unclear. Here, we observed that NPC patients had upregulated OPN at mRNA protein and levels. Immunochemistry (IHC) analysis of OPN expression in 68 NPC clinical specimens indicated that high expression of OPN had positive correlation with NPC lymph node metastasis (P = 0.012), distant metastasis (P = 0.001) and TNM staging (P = 0.018). Moreover, compared with relatively low OPN, NPC patients with higher expression of OPN showed a poorer overall survival rate (P = 0.001, log rank test). Multivariate analysis showed that OPN expression in NPC was an independent prognostic marker. The proliferation, apoptosis and migration ability of CEN-2Z cancer cells in NPC were determined by MTT, flow cytometry and wound-healing assays, respectively. Upregulation of OPN in CEN-2Z cancer cells promoted cancer cell proliferation and migration, and suppressed apoptosis. In sum, our result suggests OPN could be used as a valuable oncoprotein and show that overexpression of OPN in NPC may serve as a potential prognostic marker.