Li Wang

Identification of MACC1 as a novel prognostic marker in hepatocellular carcinoma

BackgroundMetastasis-associated in colon cancer-1 (MACC1) is a newly identified gene that plays a role in colon cancer metastasis through upregulation of c-MET proto-oncogene (c-MET). However, the value of MACC1 as a potential biomarker for hepatocellular carcinoma (HCC) remains unknown.MethodsMACC1 mRNA expression in 128 HCC tissues was examined by quantitative polymerase chain reaction. To show the potential correlation of MACC1 and c-MET, c-MET was also analysed.ResultsMACC1 was more highly expressed in HCC than in non-HCC tissues (P = 0.009). High MACC1 expression was significantly increased in cases with high alpha fetoprotein (AFP) (P = 0.025). A positive correlation was found between MACC1 and c-MET mRNAs (r = 0.235, P = 0.009). Both univariate and multivariate analyses revealed that MACC1 expression was associated with overall survival (OS) and disease-free survival (DFS). Moreover, stratified analysis showed that tumour-node-metastasis (TNM) stage I patients with high MACC1 levels had shorter OS and DFS than those with low MACC1.ConclusionsMACC1 may identify low- and high-risk individuals with HCC and be a valuable indicator for stratifying the prognosis of TNM stage I patients. MACC1 may serve as a novel biomarker for HCC.

Role of Sox2 and Oct4 in predicting survival of hepatocellular carcinoma patients after hepatectomy

OBJECTIVESnThe present study was aimed to explore the prognostic strength of Sox2 and Oct4A in hepatocellular carcinoma (HCC).nnnDESIGN AND METHODSnWe investigated the expression of Sox2 and Oct4A in five hepatoma cell lines, one immortalized normal liver cell line, HCC tissues with matched nontumorous liver tissues and normal liver tissues by reverse transcription-polymerase chain reaction.nnnRESULTSnSox2 and Oct4A mRNA were overexpressed in hepatoma cell lines and tumor tissues. Sox2 or Oct4A positive expression was significantly associated with an aggressive phenotype. Both univariate and multivariate analyses revealed that Sox2 or Oct4A was an independent prognostic factor for HCC. When using subgroup analysis, the patients with a co-expression of Sox2/Oct4A had the poorest prognosis. Further analysis demonstrated that Sox2 alone or Sox2/Oct4A could stratify outcome in HCC patients with early stage.nnnCONCLUSIONSnSox2 and Oct4A can be novel predictors of poor prognosis for patients undergoing resection of HCC.

hSSB1 regulates both the stability and the transcriptional activity of p53

The tumor suppressor p53 is essential for several cellular processes that are involved in the response to diverse genotoxic stress, including cell cycle arrest, DNA repair, apoptosis and senescence. Studies of the regulation of p53 have mostly focused on its stability and transactivation; however, new regulatory molecules for p53 have also been frequently identified. Here, we report that human ssDNA binding protein SSB1 (hSSB1), a novel DNA damage-associated protein, can interact with p53 and protect p53 from ubiquitin-mediated degradation. Furthermore, hSSB1 also associates with the acetyltransferase p300 and is required for efficient transcriptional activation of the p53 target gene p21 by affecting the acetylation of p53 at lysine382. Functionally, the hSSB1 knockdown-induced abrogation of the G2/M checkpoint is partially dependent on p53 or p300. Collectively, our results indicate that hSSB1 may regulate DNA damage checkpoints by positively modulating p53 and its downstream target p21.

Down‐regulation of prostate stem cell antigen (PSCA) by Slug promotes metastasis in nasopharyngeal carcinoma

Distant metastasis and local recurrence are still the major causes for failure of treatment in patients with nasopharyngeal carcinoma (NPC), making it urgent to further elicit the molecular mechanisms of NPC metastasis. Using a gene microarray including transcription factors and known markers for cancer stem cells, prostate stem cell antigen (PSCA) was found to be significantly down‐regulated in metastatic NPC in lymph node, compared to its primary tumour, and in NPC cell lines with high metastatic ability compared to those with low metastatic ability. NPC patients with low PSCA expression had a consistently poor metastasis‐free survival (p = 0.003). Knockdown and overexpression of PSCA respectively enhanced and impaired the migration and invasion in vitro and the lung metastasis in vivo of NPC cells. Mechanistically, the enhancement of NPC metastasis by knocking down PSCA probably involved epithelial–mesenchymal transition (EMT), by up‐regulating N‐cadherin and ZEB1/2 and by activating RhoA. The down‐regulation of PSCA in NPC cells resulted directly from the binding of Slug to the PSCA promoter. PSCA may be a potential diagnostic marker and therapeutic target for patients with NPC. Copyright

TEL2 suppresses metastasis by down-regulating SERPINE1 in nasopharyngeal carcinoma

Metastasis is the major cause of treatment failure in patients with nasopharyngeal carcinoma (NPC). However, the molecular mechanisms of NPC metastasis are poorly understood. Here, using our customized gene microarray containing all of the known human transcription factors and the current markers for epithelial-mesenchymal transition, we report that TEL2 was down-regulated in highly metastatic NPC cells and the metastatic tissues in lymph node. Mechanistically, TEL2 inhibits the cell migration and invasion in vitro and metastasis in vivo by releasing its direct suppression on the SERPINE1 promoter in NPC. Consistently, an inverse correlation was observed between the protein levels of TEL2 and SERPINE1 using clinical NPC samples. Collectively, we have provided the first evidence that TEL2 plays a key role in NPC metastasis by directly down-regulating SERPINE1, and that this novel axis of TEL2 / SERPINE1 may be valuable to develop new strategies for treating NPC patients with metastasis.

LIN28 expression and prognostic value in hepatocellular carcinoma patients who meet the Milan criteria and undergo hepatectomy

Stem cell marker LIN28, related closely with SOX2 and OCT4, has been studied as a biomarker for the maintainance of pluripotent cells in several malignancies. Our previous study showed that SOX2 and OCT4 were negative predictors for hepatocellular carcinoma (HCC). However, the predictive value of LIN28 in HCC outcome is still undetermined. We hypothesized that LIN28 may also play a role as a biomarker for HCC. To test this hypothesis, we examined the expression of LIN28 in 129 radically resected HCC tissues using reverse transcription-polymerase chain reaction and analyzed the association of LIN28 expression with clinicopathologic features and prognosis. Our study showed that LIN28 was expressed at a higher frequency in tumor tissues than in non-HCC tissues (45.0% vs. 21.7%, P = 0.020). Moreover, LIN28 expression was significantly increased in cases with large tumor size (P = 0.010). Univariate analysis did not reveal a significant correlation between LIN28 expression and overall survival or recurrence-free survival. For HCC patients who met the Milan criteria, stratified analysis revealed shorter overall survival (P = 0.007) and recurrence-free survival (P < 0.001) in those with detectable LIN28 expression compared to those with no detectable LIN28 expression. Furthermore, multivariate analysis revealed that LIN28 was a negative independent predictor for both overall survival (hazard ratio= 7.093, P = 0.017) and recurrence-free survival (hazard ratio=5.518, P = 0.004) in patients who met the Milan criteria. Taken together, our results suggest that LIN28 identifies low-risk and high-risk subsets of HCC patients meeting the Milan criteria who undergo hepatectomy.

Prognostic value of Wnt inhibitory factor-1 expression in hepatocellular carcinoma that is independent of gene methylation.

Recently, Wnt inhibitory factor-1 (WIF-1) was found to be epigenetically inactivated in several solid tumors, but the biological and clinical relevance of WIF-1 methylation and expression status in hepatocellular carcinoma (HCC) are still unclear. In the present study, reverse transcription polymerase chain reaction (PCR) and methylation-specific PCR were used to examine the WIF-1 expression and methylation in HCC cell lines. In addition, methylation and expression status of WIF-1 in 105 HCC cases were correlated with clinicopathological parameters and prognosis after tumor resection. WIF-1 was expressed in one HCC cell line and L02, both of which were not methylated in promoter region. DNA hypermethylation of WIF-1 promoter was identified in the other four HCC cell lines without WIF-1 expression. In neoplastic and non-neoplastic tissue samples, the rates of WIF-1 methylation were 61.9% and 37.1% (Pu2009=u20090.001), respectively. WIF-1 was significantly downregulated in neoplastic tissues at messenger ribonucleic acid (mRNA) level, as compared to adjacent non-neoplastic tissues (Pu2009=u20090.006). A significant inverse association was observed between WIF-1 methylation of and WIF-1 expression (Pu2009=u20090.017, Ru2009=u2009−0.232). Methylation of WIF-1 was not associated with patient survival. In contrast, patients whose tumors exhibited negative WIF-1 mRNA expression had lower rates of overall survival. These findings suggested that aberrant methylation of WIF-1 is a common event in hepatocarcinogenesis. In addition, expression, but not methylation, of WIF-1 is a predictor of good outcome in patients undergoing resection of HCC.

c-Src activation promotes nasopharyngeal carcinoma metastasis by inducing the epithelial-mesenchymal transition via PI3K/Akt signaling pathway: A new and promising target for NPC

Aberrant activation of cellular Src (c-Src), a non-receptor tyrosine kinase, could promote cancer progression through activating its downstream signaling pathways. However, the roles of c-Src and phosphorylated-Src (p-Src) in nasopharyngeal carcinoma (NPC) progression are rarely investigated. Herein, we have identified high c-Src concentrations in the serum of NPC patients with distant metastasis using high-throughput protein microarrays. Levels of c-Src in serum and p-Src in human primary NPC samples were unfavorable independent prognostic factors for cancer-specific survival, disease-free survival, and distant metastasis-free survival. Depletion or inactivation of c-Src in NPC cells using sgRNA with CRISPR/Cas9 system or PP2 decreased cell viability, colony formation, migration and invasion in vitro and metastasis in vivo. In contrast, these malignancies could be up-regulated by overexpressed c-Src in a NPC cell line with low-metastasis potential. Furthermore, p-Src was involved in promoting NPC cell metastasis by inducing the epithelial-mesenchymal transition (EMT) process via activating the PI3K/Akt pathway and cytoskeleton remodeling. The p-Src-induced EMT process could be retarded by PP2, which mediated by down-regulating the PI3K/Akt pathway. In conclusion, elevated levels of c-Src in serum and p-Src in primary NPC tissue correlated with poor outcomes of NPC patients. And aberrant activation of c-Src facilitated NPC cells with malignant potential, especially metastasis ability, which mediated by the PI3K/Akt pathway activation and sequentially induced the EMT process. These findings unveiled a promising approach for targeted therapy of advanced NPC.

A genome-scale CRISPR-Cas9 screening method for protein stability reveals novel regulators of Cdc25A

The regulation of stability is particularly crucial for unstable proteins in cells. However, a convenient and unbiased method of identifying regulators of protein stability remains to be developed. Recently, a genome-scale CRISPR-Cas9 library has been established as a genetic tool to mediate loss-of-function screening. Here, we developed a protein stability regulators screening assay (Pro-SRSA) by combining the whole-genome CRISPR-Cas9 library with a dual-fluorescence-based protein stability reporter and high-throughput sequencing to screen for regulators of protein stability. Using Cdc25A as an example, Cul4B-DDB1DCAF8 was identified as a new E3 ligase for Cdc25A. Moreover, the acetylation of Cdc25A at lysine 150, which was acetylated by p300/CBP and deacetylated by HDAC3, prevented the ubiquitin-mediated degradation of Cdc25A by the proteasome. This is the first study to report that acetylation, as a novel posttranslational modification, modulates Cdc25A stability, and we suggest that this unbiased CRISPR-Cas9 screening method at the genome scale may be widely used to globally identify regulators of protein stability.

Low expression of centrosomal protein 78(CEP78) is associated with poor prognosis of colorectal cancer patients

BackgroundCentrosomal protein 78 (CEP78) has been characterized as a component of the centrosome required for the regulation of centrosome-related events during the cell cycle, but its role in human cancers remains unclear. This study aimed to investigate the role and the clinical value of CEP78 in colorectal cancer (CRC).MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry were performed to examine CEP78 expression in CRC tissues and adjacent noncancerous tissues. The association between CEP78 expression and clinical outcomes of CRC patients was determined. The effect of CEP78 on cell growth was examined in vitro by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, colony formation, and flow cytometry assays and in vivo using a nude mouse model.ResultsThe expression level of CEP78 was significantly lower in tumor tissues than in the adjacent normal tissues (Pxa0<xa00.01). Low CEP78 expression was significantly associated with poor differentiation (Pxa0=xa00.003), large tumor size (Pxa0=xa00.017), lymphatic metastasis (Pxa0=xa00.034), distant metastasis (Pxa0=xa00.029), and advanced stage (Pxa0=xa00.011). Kaplan–Meier analysis indicated that patients with low CEP78 expression had shorter survival than those with high CEP78 expression (Pxa0<xa00.01). Overexpression of CEP78 in CRC cells significantly reduced cell viability and colony formation in vitro and halted tumor growth in vivo. Further study showed that CEP78 reintroduction in CRC cells resulted in G2/M phase arrest rather than cell apoptosis.ConclusionsCEP78 might function as a tumor suppressor and serve as a novel prognostic marker in CRC.