Jian-Yong Shao

Tumor suppressor genes function to regulate and block tumor cell proliferation. To explore the mechanisms underlying the tumor suppression of BLU/ZMYND10 gene on a frequently lost human chromosomal region, an adenoviral vector with BLU cDNA insert was constructed.

Background: The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all EBV-associated tumours, including undifferentiated nasopharyngeal carcinoma (NPC), where it is indispensable for viral replication, genome maintenance and viral gene expression. EBNA1's transcription factor-like functions also extend to influencing the expression of cellular genes involved in pathways commonly dysregulated during oncogenesis, including elevation of AP-1 activity in NPC cell lines resulting in enhancement of angiogenesis in vitro. In this study we sought to extend these observations by examining the role of EBNA1 upon another pathway commonly deregulated during carcinogenesis; namely NF-κB. Results: In this report we demonstrate that EBNA1 inhibits the canonical NF-κB pathway in carcinoma lines by inhibiting the phosphorylation of IKKα/β. In agreement with this observation we find a reduction in the phosphorylation of IκBα and reduced phosphorylation and nuclear translocation of p65, resulting in a reduction in the amount of p65 in nuclear NF-κB complexes. Similar effects were also found in carcinoma lines infected with recombinant EBV and in the EBV-positive NPC-derived cell line C666-1. Inhibition of NF-κB was dependent upon regions of EBNA1 essential for gene transactivation whilst the interaction with the deubiquitinating enzyme, USP7, was entirely dispensable. Furthermore, in agreement with EBNA1 inhibiting p65 NF-κB we demonstrate that p65 was exclusively cytoplasmic in 11 out of 11 NPC tumours studied. Conclusions: Inhibition of p65 NF-κB in murine and human epidermis results in tissue hyperplasia and the development of squamous cell carcinoma. In line with this, p65 knockout fibroblasts have a transformed phenotype. Inhibition of p65 NF-κB by EBNA1 may therefore contribute to the development of NPC by inducing tissue hyperplasia. Furthermore, inhibition of NF-κB is employed by viruses as an immune evasion strategy which is also closely linked to oncogenesis during persistent viral infection. Our findings therefore further implicate EBNA1 in playing an important role in the pathogenesis of NPC.

Expression of caveolin-1 (Cav-1) and extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) and their prognostic significance were analyzed in archive NPC samples. Cav-1 and CD147 were overexpressed in 49.48% (96/194) and 59.39% (117/197) of NPC, respectively. Both Cav-1 and CD147 expression levels correlated significantly with metastasis (p = 0.025 and 0.017, respectively) and a lower 5-year survival rate (p = 0.02 and 0.0009, respectively). In addition, Cav-1 expression levels correlated significantly with local recurrence (p = 0.038). Multivariate Cox regression analysis indicated that combination of high Cav-1 and CD147 expression was a significant, independent prognosis predictor in patients with NPC (HR = 2.135; p = 0.006). Functional studies revealed that overexpression of Cav-1 promoted secretion of MMP-3 and MMP-11 (active) proteins, as well as an increase in the migratory ability of CNE1 and CNE2 cells, while siRNA-mediated silencing of Cav-1 or CD147 led to reduced levels of MMP-3 and MMP-11(active) secretion, and reduced migration capacity of CNE1 and CNE2 cells. We observed a positive correlation between Cav-1 and CD147 expression in NPC (ρ = 0.330, p = 0.000), CD147 protein levels were upregulated in Cav-1 overexpressing CNE1 and CNE2 cells, whereas siRNA-mediated silencing of Cav-1 led to the downregulation of CD147 expression. Our results indicate that Cav-1 and CD147 overexpression predict poor NPC prognosis and enhanced tumor cell migration, which is associated with MMP-3 and MMP-11 (active) secretion. © 2009 UICC

To investigate the global expression profile of miRNAs in primary breast cancer (BC) and normal adjacent tumor tissues (NATs) and its potential relevance to clinicopathological characteristics and patient survival, the genome-wide expression profiling of miRNAs in BC was investigated using a microarray containing 435 mature human miRNA oligonucleotide probes. Nine miRNAs of hsa-miR-21, hsa-miR-365, hsa-miR-181b, hsa-let-7f, hsa-miR-155, hsa-miR-29b, hsa-miR-181d, hsa-miR-98, and hsa-miR-29c were observed to be up-regulated greater than twofold in BC compared with NAT, whereas seven miRNAs of hsa-miR-497, hsa-miR-31, hsa-miR-355, hsa-miR-320, rno-mir-140, hsa-miR-127 and hsa-miR-30a-3p were observed to be down-regulated greater than twofold. The most significantly up-regulated miRNAs, hsa-mir-21 (miR-21), was quantitatively analyzed by TaqMan real-time PCR in 113 BC tumors. Interestingly, among the 113 BC cases, high level expression of miR-21 was significantly correlated with advanced clinical stage (P = 0.006, Fisher's exact text), lymph node metastasis (P = 0.007, Fisher's exact text), and shortened survival of the patients (hazard ratio [HR]=5.476, P < 0.001). Multivariate Cox regression analysis revealed this prognostic impact (HR=4.133, P = 0.001) to be independent of disease stage (HR=2.226, P = 0.013) and histological grade (HR=3.681, P = 0.033). This study could identify the differentiated miRNAs expression profile in BC and reveal that miR-21 overexpression was correlated with specific breast cancer biopathologic features, such as advanced tumor stage, lymph node metastasis, and poor survival of the patients, indicating that miR-21 may serve as a molecular prognostic marker for BC and disease progression.

Background: Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in southern China. The China 1992 TNM staging system has been widely used for prognosis prediction of NPC patients in China. Although NPC patients can be classified according to their clinical stage in this system, their prognosis may vary significantly. Method: 280 cases of NPC with clinical follow-up data were collected and expressions of survivin and VEGF in tumor tissues were investigated by immunohistochemistry (IHC). Apoptosis index (AI) in 100 cases of NPC was detected by the TUNEL method. Results: Expression of survivin and VEGF were significantly associated with TNM stage, T-stage and metastasis of NPC. The patients with survivin and VEGF over-expression presented lower 5-year survival rate, as compared to those of low-expression (42.32% vs. 70.54%, 40.1% vs. 67.8%, respectively, P < 0.05), especially in advanced stage patients (36.51% vs. 73.41%, 35.03% vs. 65.22%, respectively, P < 0.05). The 5-year survival rate in NPC patients with survivin and VEGF dual over-expression was significantly lower than that of patients with dual low-expression (18.22% vs. 73.54%, respectively; P = 0.0003). Multivariate analysis indicated that both survivin and VEGF over-expression in NPC tumor tissues were strong independent factors of poor prognosis in NPC patients. The mean AI in the 39 survivin low-expression cases was 144.7 ± 39.9, which was significantly higher than that in 61 survivin over-expression cases (111.6 ± 39.8) (T test, P < 0.05). Conclusion: Survivin and VEGF over-expression are independent prognostic factors for the patients with NPC. These results also suggest that tumor survivin and VEGF expressions are valuable prognostic markers for prognosis prediction in NPC patients.

Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China. In addition to environmental factors such as Epstein-Barr virus infection and diet, genetic susceptibility has been reported to play a key role in the development of this disease. The x-ray repair cross-complementing group 1 (XRCC1) gene is important in DNA base excision repair. We hypothesized that two common single nucleotide polymorphisms of XRCC1 (codons 194 Arg→Trp and 399 Arg→Gln) are related to the risk of NPC and interact with tobacco smoking. We sought to determine whether these genetic variants of the XRCC1 gene were associated with the risk of NPC among the Cantonese population in a hospital-based case control study using polymerase chain reaction-restriction fragment length polymorphism analysis. We conducted this study in 462 NPC patients and 511 healthy controls. After adjustment for sex and age, we found a reduced risk of developing NPC in individuals with the Trp194Trp genotype (OR = 0.48; 95% CI, 0.27–0.86) and the Arg194Trp genotype (OR = 0.79; 95% CI, 0.60–1.05) compared with those with the Arg194Arg genotype. Compared with those with the Arg399Arg genotype, the risk for NPC was not significantly different in individuals with the Arg399Gln genotype (OR = 0.82; 95% CI, 0.62–1.08) and the Gln399Gln genotype (OR = 1.20; 95% CI, 0.69–2.06). Further analyses stratified by gender and smoking status revealed a significantly reduced risk of NPC among males (OR = 0.32; 95% CI, 0.14–0.70) and smokers (OR = 0.34; 95% CI, 0.14–0.82) carrying the XRCC1 194Trp/Trp genotype compared with those carrying the Arg/Arg genotype. No association was observed between Arg399Gln variant genotypes and the risk of NPC combined with smoking and gender. Our findings suggest that the XRCC1 Trp194Trp variant genotype is associated with a reduced risk of developing NPC in Cantonese population, particularly in males and smokers. Larger studies are needed to confirm our findings and unravel the underlying mechanisms.