Xuebing Yan

N-cadherin, a novel prognostic biomarker, drives malignant progression of colorectal cancer

Recent studies have indicated that the epithelial-mesenchymal transition (EMT) is a key molecular mechanism involved in the development of colorectal cancer (CRC). N-cadherin is a mesenchymal marker of the EMT and has been closely linked to several human malignancies. However, its role in CRC has remained elusive. In the present study, qRT-PCR and western blot analysis indicated that N-cadherin expression was higher in tumor tissues than in that in their adjacent normal tissues. Immunohistochemical evaluation of N-cadherin and E-cadherin (an epithelial marker of the EMT), indicated that N-cadherin expression was significantly associated with tumor differentiation, tumor size as well as tumor, nodes and metastasis stage. Correlation analysis suggested the expression of N-cadherin was negatively correlated with that of E-cadherin in CRC tissues. Kaplan-Meier analysis indicated that patients with high N-cadherin expression had a significantly lower overall survival and disease-free survival rate than those with low N-cadherin expression, while the opposite was found for E-cadherin. Of note, the present study found that high N-cadherin expression was an independent prognostic factor for CRC. In vitro assays showed that N-cadherin was widely expressed in CRC cell lines and silencing of N-cadherin suppressed the proliferation and migration of the CRC cell line HT-29 by upregulating E-cadherin, suggesting a potential role of N-cadherin in inducing EMT. In conclusion, the present study suggested that N-cadherin has the potential of serving as a novel prognostic predictor and a promising therapeutic target for CRC.

High expression of Zinc-finger protein X-linked promotes tumor growth and predicts a poor outcome for stage II/III colorectal cancer patients

Zinc-finger protein X-linked (ZFX) was recently identified as a novel oncoprotein in several human malignancies. In this study, we examined the correlation between ZFX expression and the clinical characteristics of stage II/III CRC patients, as well as the molecular mechanism by which ZFX apparently contributes to CRC tumor progression. Using immunohistochemistry, we detected expression of ZFX in CRC tissues collected from stage II/III patients and determined that its expression correlated with tumor differentiation and stage. Survival analysis indicated that patients with high ZFX expression had poorer overall and disease-free survival. ZFX knockdown in SW620 and SW480 CRC cells significantly inhibited cell proliferation and colony formation, enhanced apoptosis and induced cell cycle arrest. It also enhanced the sensitivity of CRC cells to 5-Fu. In a xenograft model, ZFX knockdown suppressed in vivo CRC tumor growth. Microarray analysis revealed the primary target of ZFX to be DUSP5. Whereas ZFX knockdown increased DUSP5 expression, DUSP5 knockdown rescued ZFX-mediated cell proliferation in ZFX knockdown cells. These findings demonstrate that ZFX promotes CRC progression by suppressing DUSP5 expression and suggest that ZFX is a novel prognostic biomarker and potentially useful therapeutic target in stage II/III CRC patients.

Systematic literature review and clinical validation of circulating microRNAs as diagnostic biomarkers for colorectal cancer

Because patients with colorectal cancer (CRC) are usually diagnosed at an advanced stage and current serum tumor markers have limited diagnostic efficacy, there is an urgent need to identify reliable diagnostic biomarkers. To better define the diagnostic potential of microRNAs (miRNAs) for CRC, we performed a comprehensive evaluation of reported circulating CRC miRNA markers. After a systematic literature review, we selected 30 candidate miRNAs and used quantitative real-time polymerase chain reaction to examine their expression in a training cohort of 120 plasma samples (CRC vs healthy controls (HC) = 60:60). Expression data was confirmed in a validation cohort of 160 plasma samples (CRC vs HC = 80:80). We ultimately identified 5 dysregulated circulating miRNAs (miR-15b, miR-17, miR-21, miR-26b, and miR-145), of which miR-21 and miR-26b proved to have the best diagnostic performance in the training and validation cohorts, respectively. Based on these results, we propose a novel blood-based diagnostic model, integrating 5 CRC-related miRNAs and serum carcinoembryonic antigen (CEA), which provides better diagnostic performance than the combined 5 miRNAs, CEA alone, or any single miRNA. We propose that the novel CRC diagnostic model presented here will be useful for overcoming the limitations faced by current non-invasive diagnostic strategies.Because patients with colorectal cancer (CRC) are usually diagnosed at an advanced stage and current serum tumor markers have limited diagnostic efficacy, there is an urgent need to identify reliable diagnostic biomarkers. To better define the diagnostic potential of microRNAs (miRNAs) for CRC, we performed a comprehensive evaluation of reported circulating CRC miRNA markers. After a systematic literature review, we selected 30 candidate miRNAs and used quantitative real-time polymerase chain reaction to examine their expression in a training cohort of 120 plasma samples (CRC vs healthy controls (HC) = 60:60). Expression data was confirmed in a validation cohort of 160 plasma samples (CRC vs HC = 80:80). We ultimately identified 5 dysregulated circulating miRNAs (miR-15b, miR-17, miR-21, miR-26b, and miR-145), of which miR-21 and miR-26b proved to have the best diagnostic performance in the training and validation cohorts, respectively. Based on these results, we propose a novel blood-based diagnostic model, integrating 5 CRC-related miRNAs and serum carcinoembryonic antigen (CEA), which provides better diagnostic performance than the combined 5 miRNAs, CEA alone, or any single miRNA. We propose that the novel CRC diagnostic model presented here will be useful for overcoming the limitations faced by current non-invasive diagnostic strategies.

Clinical significance of Fusobacterium nucleatum , epithelial–mesenchymal transition, and cancer stem cell markers in stage III/IV colorectal cancer patients

Colorectal cancer (CRC) is a common digestive malignancy and emerging studies have closely linked its initiation and development with gut microbiota changes. Fusobacterium nucleatum (Fn) has been recently identified as a pathogenic bacteria for CRC; however, its prognostic significance for patients is poorly investigated and is less for patients within late stage. Therefore, in this study, we made efforts to analyze its level and prognostic significance in a retrospective cohort of 280 stage III/IV CRC patients. We found that the Fn level was abnormally high in tumor tissues and correlated with tumor invasion, lymph node metastasis status, and distant metastasis. We also identified it as an independent adverse prognostic factor for cancer-specific survival (CSS) and disease-free survival (DFS). The following subgroup analysis indicated that Fn level could stratify CSS and DFS in stage IIIB/C and IV patients but failed in stage IIIA patients. In addition, stage III/IV patients with low Fn level were found to benefit more from adjuvant chemotherapy than those with high Fn level, in terms of DFS. Finally, we analyzed the expression and clinical significance of epithelial-to-mesenchymal transition (EMT) markers (E-cadherin and N-cadherin) and cancer stem cell (CSC) markers (Nanog, Oct-4, and Sox-2) in CRC tissues. The results indicated that N-cadherin, Nanog, Oct-4, and Sox-2 were adverse prognostic factors in these patients, while the opposite was true for E-cadherin. More importantly, expression of E-cadherin, N-cadherin, and Nanog was significantly correlated with Fn level in tumor tissues, suggesting the potential involvement of Fn in EMT-CSC cross talk during CRC progression. Taken together, these findings indicate that Fn is a novel predictive biomarker for clinical management in stage III/IV patients, and targeting Fn may be an effective adjuvant approach for preventing CRC metastasis and chemotherapy resistance.

Pleiotrophin promotes chemoresistance to doxorubicin in osteosarcoma by upregulating P-glycoprotein

Chemoresistance is a major hindrance to successful treatment of osteosarcoma (OS). Pleiotrophin (PTN), a neurotrophic growth factor, has been linked to the malignant characteristics of various cancer types. We retrospectively examined the correlation between PTN expression and chemoresistance in OS in a cohort of 133 OS patients. Immunohistochemistry revealed that PTN expression correlated with the necrosis rate and local OS recurrence. In a prognostic analysis, high PTN expression was associated with poor overall and disease-free survival, and was an independent adverse prognostic factor for disease-free survival. In doxorubicin-treated OS cells, PTN knockdown enhanced cellular chemosensitivity, increased the apoptosis rate and inhibited clone formation, while PTN overexpression had the opposite effects. In a xenograft model, PTN knockdown and overexpression respectively enhanced and reduced cellular sensitivity to doxorubicin. PTN upregulated anaplastic lymphoma kinase (ALK), p-Glycogen Synthase Kinase (GSK)3β, β-catenin and multidrug resistance protein 1/P-glycoprotein (MDR1/P-gp). In rescue assays with the β-catenin inhibitor XAV939 and the MDR1/P-gp inhibitor verapamil, PTN promoted chemoresistance to doxorubicin in OS cells by activating ALK/GSK3β/β-catenin signaling, thereby upregulating MDR1/P-gp. Therefore, PTN could be used as a biomarker predicting chemotherapeutic responses, and downregulating PTN could be a promising therapeutic strategy to prevent chemoresistance in OS patients.Chemoresistance is a major hindrance to successful treatment of osteosarcoma (OS). Pleiotrophin (PTN), a neurotrophic growth factor, has been linked to the malignant characteristics of various cancer types. We retrospectively examined the correlation between PTN expression and chemoresistance in OS in a cohort of 133 OS patients. Immunohistochemistry revealed that PTN expression correlated with the necrosis rate and local OS recurrence. In a prognostic analysis, high PTN expression was associated with poor overall and disease-free survival, and was an independent adverse prognostic factor for disease-free survival. In doxorubicin-treated OS cells, PTN knockdown enhanced cellular chemosensitivity, increased the apoptosis rate and inhibited clone formation, while PTN overexpression had the opposite effects. In a xenograft model, PTN knockdown and overexpression respectively enhanced and reduced cellular sensitivity to doxorubicin. PTN upregulated anaplastic lymphoma kinase (ALK), p-Glycogen Synthase Kinase (GSK)3β, β-catenin and multidrug resistance protein 1/P-glycoprotein (MDR1/P-gp). In rescue assays with the β-catenin inhibitor XAV939 and the MDR1/P-gp inhibitor verapamil, PTN promoted chemoresistance to doxorubicin in OS cells by activating ALK/GSK3β/β-catenin signaling, thereby upregulating MDR1/P-gp. Therefore, PTN could be used as a biomarker predicting chemotherapeutic responses, and downregulating PTN could be a promising therapeutic strategy to prevent chemoresistance in OS patients.

Overexpression of the cancer stem cell marker CD117 predicts poor prognosis in epithelial ovarian cancer patients: evidence from meta-analysis

Purpose Cancer stem cells have recently been identified as a key driving factor for tumor metastasis and chemoresistance. CD117 is a well-established cancer stem cell marker, but its clinical significance in epithelial ovarian cancer (EOC) remains controversial. Therefore, we aimed to identify correlations between CD117 expression and clinical features and outcomes in EOC patients in this meta-analysis. Materials and methods A literature search was performed in the PubMed, Cochrane Library, Web of Science, EMBASE, and OVID databases to identify eligible studies. Correlations between CD117 expression and clinicopathological parameters and overall survival or disease-free survival were analyzed. A subgroup analysis was then performed, which was classified by patient ethnicity and age at diagnosis, study sample size, and tumor histological type. Results A total of seven studies enrolling 1,247 EOC patients were included in this meta-analysis. Our results demonstrated that CD117 expression was significantly correlated with age (pooled odds ratio [OR] =1.67, 95% confidence interval [CI] =1.05–2.66), International Federation of Gynecology and Obstetrics stage (pooled OR =1.99, 95% CI =1.31–3.02), tumor differentiation grade (pooled OR =2.46, 95% CI =1.48–4.10), and histological type (pooled OR =1.85, 95% CI =1.05–3.26). EOC patients with high CD117 expression had significantly worse OS (hazard ratio [HR] =1.39, 95% CI =1.03–1.90) than patients with low CD117 expression. However, no significant correlation was found between CD117 expression and disease-free survival (HR =1.31, 95% CI =0.79–2.17). In subgroup analysis, CD117 was identified as a significant prognostic factor for overall survival in European patients (HR =1.59, 95% CI =1.13–2.23), younger patients (<60 years) (HR =1.59, 95% CI =1.10–2.30), studies with sample sizes >200 (HR =1.84, 95% CI =1.32–2.56), and the mixed histological types (HR =1.47; 95% CI =1.08–2.00). Conclusion Our meta-analysis suggests that CD117 is associated with EOC progression and can serve as a promising prognostic predictor for EOC patients. However, larger scale multicenter clinical trials are still needed to further validate our results.

Application of dual targeting drug delivery system for the improvement of anti-glioma efficacy of doxorubicin

Chemotherapy of glioma is always hampered by the unsatisfactory tumor accumulation of drugs, of which the most noticeable obstacle is the limited drug permeability from vessels into tumor inner. In the present study, we developed a novel nanocarrier for the delivery of doxorubicin to brain tumor. Such novel drug delivery system was mainly composed of a tumor homing peptide and DOX-loaded PLA nanoparticles (AP1-NP-DOX). CRKRLDRNC peptide, named as AP1, was a newly glioma affinity peptide which could specifically binds to interleukin-4 receptor (IL-4R), highly expressing on both glioma cells and angiogenesis. Our findings showed that the peptide-functionalized nanoparticles had a high affinity with both tumor cells and vascular endothelial cells. Besides, tumor targeting assay exhibited that AP1 decorated nanoparticles accumulated more in tumor site than the unmodified ones. Moreover, the results of tumor uptake experiments indicated that AP1-NP-DOX might own the ability of blood brain barrier (BBB) penetration. In the anti-glioma study, AP1-NP-DOX exhibited the highest therapeutic effect on tumor-bearing mice compared with the unmodified nanoparticles and free doxorubicin. These results together indicated that AP1-functionalized nanoparticles could represent a promising way to expand the treatment horizons of onco-therapy.

High expression of Ras-related protein 1A promotes an aggressive phenotype in colorectal cancer via PTEN/FOXO3/CCND1 pathway

BackgroundColorectal cancer (CRC) is a commonly diagnosed digestive malignancy worldwide. Ras-related protein 1A (RAP1A) is a member of the Ras superfamily of small GTPases and has been recently identified as a novel oncoprotein in several human malignancies. However, its specific role in CRC remains unclear.MethodIn this study, we firstly analyzed its expression and clinical significance in a retrospective cohort of 144 CRC patients. Then, cellular assays in vitro and in vivo were performed to clarify its biological role in CRC cells. Finally, microarray analysis was utilized to investigate the molecular mechanisms regulated by RAP1A in CRC progression.ResultsFirstly, RAP1A expression was abnormally higher in CRC tissues as compared with adjacent normal tissues, and significantly correlated tumor invasion. High RAP1A expression was an independent unfavourable prognostic factor for CRC patients. Combining RAP1A expression and preoperative CEA level contributed to a more accurate prognostic stratification in CRC patients. Secondly, knockdown of RAP1A dramatically inhibited the growth of CRC cells, while it was opposite for RAP1A overexpression. Finally, the microarray analysis revealed RAP1A promoted CRC growth partly through phosphatase and tensin homolog (PTEN)/forkhead box O3(FOXO3)/cyclin D1(CCND1) signaling pathway. FOXO3 overexpression could partly mimic the inhibitory effect of RAP1A knockdown in CRC growth. Moreover, FOXO3 overexpression inhibited CCND1 expression, but had no impact on RAP1A and PTEN expression.ConclusionRAP1A promotes CRC development partly through PTEN/FOXO3 /CCND1 signaling pathway. It has a great potential to be an effective clinical biomarker and therapeutic target for CRC patients.