Xinjuan Fan

NFκB1 and NFκBIA polymorphisms are associated with increased risk for sporadic colorectal cancer in a southern Chinese population.

Background Nuclear factor κB (NFκB) plays a key role in the regulation of apoptosis. The function of NFκB is inhibited by binding to NFκB inhibitor (IκB), and disruption of the balance of NFκB and IκB is related to the development of many diseases, including tumors. Therefore, we hypothesized that the NFκB1 (-94del/insATTG) and NFκBIA (2758 A>G) polymorphisms were associated with colorectal cancer (CRC) susceptibility. Methods In a hospital-based case–control study of 1001 CRC patients and 1005 cancer-free controls frequency matched by age and sex, we genotyped polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and performed luciferase assays and Western blotting analysis to identify whether genetic variants in NFκBIA alter its gene expressions and functions and thus cancer risk. Results We found that both NFκB1-94 ins/delATTG and NFκBIA 2758 A>G polymorphisms were correlated with CRC risk (OR = 1.47; 95%CI = 1.14–1.86, and OR = 1.38; 95% CI = 1.14–1.66, respectively). Furthermore, when evaluated these two polymorphisms together, the combined genotypes with 2 variant (risk) alleles (2758GG and -94ins/ins+del/ins) were associated with an increased risk of CRC (OR = 1.71; 95% CI = 1.23–2.38) compared to 0 variant, and the significant trend for 2 variant (risk) alleles were more pronounced among subgroups of aged <60 years, women, never drinkers, never smokers, persons with a normal BMI and those with a family history of cancer(Ptrend<0.01). Moreover, luciferase assays showed that the G allele in the 3′UTR significantly decreased NFκBIA mRNA stability and the A allele regulation by miRNA449a in vitro and that the NFκBIA protein expression levels of the AA+AG variant carriers were significantly higher in peritumoral tissues than those of the 2758GG genotype. Conclusion NFκB1 and NFκBIA polymorphisms appear to jointly contribute to risk of CRC. These two variants may be a genetic modifier for CRC susceptibility in this southern Chinese population.

Increased urothelial cancer associated 1 is associated with tumor proliferation and metastasis and predicts poor prognosis in colorectal cancer

Long non-coding RNA, urothelial cancer associated 1 (UCA1), is reported to play a critical role in progression of carcinogenesis. In the present study, we identified differential expression of UCA1 in colorectal cancer (CRC) and paired peritumoral tissues using gene expression microarray analyses. qPCR analysis confirmed that UCA1 was upregulated in CRC (p<0.001) and the expression of UCA1 was statistically correlated with lymph node metastasis (P=0.040), distant metastasis (P=0.043) and tumor stage (P=0.010). Kaplan-Meier analysis indicated that patients with high UCA1 expression had a poor prognosis. Moreover, multivariate analysis identified UCA1 overexpression as an independent predictor for CRC. We also found that knockdown of UCA1 significantly suppressed cell proliferation and metastasis in CRC cells. Flow cytometry assays showed UCA1 silencing induced G0/G1 growth arrest and apoptosis of CRC cells. To further investigate the regulatory mechanisms of UCA1, we identified that Ets-2 bound to the UCA1 core promoter using luciferase assays. Collectively, our findings suggested that UCA1 might be an important prognostic indicator in CRC and may be a potential target for diagnosis and gene therapy.

Gene expression profiling-derived immunohistochemistry signature with high prognostic value in colorectal carcinoma

Objective Gene expression profiling provides an opportunity to develop robust prognostic markers of colorectal carcinoma (CRC). However, the markers have not been applied for clinical decision making. We aimed to develop an immunohistochemistry signature using microarray data for predicting CRC prognosis. Design We evaluated 25 CRC gene signatures in independent microarray datasets with prognosis information and constructed a subnetwork using signatures with high concordance and repeatable prognostic values. Tumours were examined immunohistochemically for the expression of network-centric and the top overlapping molecules. Prognostic values were assessed in 682 patients from Shanghai, China (training cohort) and validated in 343 patients from Guangzhou, China (validation cohort). Median follow-up duration was 58 months. All p values are two-sided. Results Five signatures were selected to construct a subnetwork. The expression of GRB2, PTPN11, ITGB1 and POSTN in cancer cells, each significantly associated with disease-free survival, were selected to construct an immunohistochemistry signature. Patients were dichotomised into high-risk and low-risk subgroups with an optimal risk score (1.55). Compared with low-risk patients, high-risk patients had shorter disease-specific survival (DSS) in the training (HR=6.62; 95% CI 3.70 to 11.85) and validation cohorts (HR=3.53; 95% CI 2.13 to 5.84) in multivariate Cox analyses. The signature better predicted DSS than did tumour-node-metastasis staging in both cohorts. In those who received postoperative chemotherapy, high-risk score predicted shorter DSS in the training (HR=6.35; 95% CI 3.55 to 11.36) and validation cohorts (HR=5.56; 95% CI 2.25 to 13.71). Conclusions Our immunohistochemistry signature may be clinically practical for personalised prediction of CRC prognosis.

Tumor-Infiltrating Mast Cells in Colorectal Cancer as a Poor Prognostic Factor

The purpose of this study is to investigate the clinical/prognostic significance of tumor-infiltrating mast cells (TIMs) in patients with colorectal cancer (CRC). TIM infiltration in 325 stage I to III CRC specimens was detected by immunohistochemistry. The optimal cutpoint of TIM density was assessed by the X-tile program. TIM infiltration in CRC was significantly higher than in normal colorectal tissues. According to the X-tile program, the cutpoint for high TIM infiltration in CRC was determined when TIM density was more than 8.0 per high-power field. Correlation analysis between TIM density and clinicopathological variables demonstrated that TIM infiltration was significantly associated with gender, nodal status, and American Joint Committee on Cancer stage. Multivariate Cox regression analysis showed that high TIM infiltration was a risk factor for both overall survival and disease-free survival. Taken together, high TIM infiltration can be an independent and useful biomarker for predicting the poor survival of patients with CRC.

Expression of the phosphorylated MEK5 protein is associated with TNM staging of colorectal cancer.

BackgroundActivation of MEK5 in many cancers is associated with carcinogenesis through aberrant cell proliferation. In this study, we determined the level of phosphorylated MEK5 (pMEK5) expression in human colorectal cancer (CRC) tissues and correlated it with clinicopathologic data.MethodspMEK5 expression was examined by immunohistochemistry in a tissue microarray (TMA) containing 335 clinicopathologic characterized CRC cases and 80 cases of nontumor colorectal tissues. pMEK5 expression of 19 cases of primary CRC lesions and paired with normal mucosa was examined by Western blotting. The relationship between pMEK5 expression in CRC and clinicopathologic parameters, and the association of pMEK5 expression with CRC survival were analyzed respectively.ResultspMEK5 expression was significantly higher in CRC tissues (185 out of 335, 55.2%) than in normal tissues (6 out of 80, 7.5%; P < 0.001). Western blotting demonstrated that pMEK5 expression was upregulated in 12 of 19 CRC tissues (62.1%) compared to the corresponding adjacent nontumor colorectal tissues. Overexpression of pMEK5 in CRC tissues was significantly correlated to the depth of invasion (P = 0.001), lymph node metastasis (P < 0.001), distant metastasis (P < 0.001) and high preoperative CEA level (P < 0.001). Consistently, the pMEK5 level in CRC tissues was increased following stage progression of the disease (P < 0.001). Analysis of the survival curves showed a significantly worse 5-year disease-free (P = 0.002) and 5-year overall survival rate (P < 0.001) for patients whose tumors overexpressed pMEK5. However, in multivariate analysis, pMEK5 was not an independent prognostic factor for CRC (DFS: P = 0.139; OS: P = 0.071).ConclusionspMEK5 expression is correlated with the staging of CRC and its expression might be helpful to the TNM staging system of CRC.

High expression of Beclin-1 predicts favorable prognosis for patients with colorectal cancer

PURPOSE Beclin-1 is an autophagy gene. It promotes the formation of the autophagic vesicle as well as plays an essential role in guarding the cells against chromosomal instability. Overexpression of Beclin-1 has been reported to predict a favorable survival in various cancers. However, little is known about its prognostic significance in colorectal cancer. METHODS AND MATERIALS A total of three hundred and sixty-three (363) colorectal tissues from colorectal cancer (CRC) patients were collected. Tissue micro-arrays and immunohistochemistry were used to investigate the expression and prognostic significance of Beclin-1 in CRC. The associations among Beclin-1 expression, clinicopathological parameters and prognosis were evaluated. RESULTS Beclin-1 had a higher expression in CRC tissues than in normal tissues. A high expression of Beclin-1 was positively correlated with gender (P=0.027), histological grade (P=0.003), pM status (P=0.003) and clinical stage (P=0.024). Patients with a high Beclin-1 expression, when compared to those with a lower expression had both a better overall survival (OS, P=0.006) and disease-free survival (DFS, P=0.008). In the pT3 subgroup, Beclin-1 was also found to be a good prognostic indicator (P<0.05). Multivariate analysis showed a high expression of Beclin-1 was indeed a positive independent prognostic factor of OS and DFS for CRC patients (P<0.05). CONCLUSION Our results demonstrated that a high expression of Beclin-1 correlated with a better overall survival and disease-free survival, thus serving as a favorable independent prognostic marker in CRC.

Epithelial–mesenchymal transition biomarkers and support vector machine guided model in preoperatively predicting regional lymph node metastasis for rectal cancer

Background:Current imaging modalities are inadequate in preoperatively predicting regional lymph node metastasis (RLNM) status in rectal cancer (RC). Here, we designed support vector machine (SVM) model to address this issue by integrating epithelial–mesenchymal-transition (EMT)-related biomarkers along with clinicopathological variables.Methods:Using tissue microarrays and immunohistochemistry, the EMT-related biomarkers expression was measured in 193 RC patients. Of which, 74 patients were assigned to the training set to select the robust variables for designing SVM model. The SVM model predictive value was validated in the testing set (119 patients).Results:In training set, eight variables, including six EMT-related biomarkers and two clinicopathological variables, were selected to devise SVM model. In testing set, we identified 63 patients with high risk to RLNM and 56 patients with low risk. The sensitivity, specificity and overall accuracy of SVM in predicting RLNM were 68.3%, 81.1% and 72.3%, respectively. Importantly, multivariate logistic regression analysis showed that SVM model was indeed an independent predictor of RLNM status (odds ratio, 11.536; 95% confidence interval, 4.113–32.361; P<0.0001).Conclusion:Our SVM-based model displayed moderately strong predictive power in defining the RLNM status in RC patients, providing an important approach to select RLNM high-risk subgroup for neoadjuvant chemoradiotherapy.

Epigenetic Inactivation and Tumor-Suppressor Behavior of NGFR in Human Colorectal Cancer

The nerve growth factor receptor (NGFR/p75) is a potential tumor suppressor, but its role in colorectal cancer is unknown. Here, the hypermethylation status, biologic function, and clinical relevance were determined for p75NGFR in colorectal cancer. The methylation status and expression of p75NGFR were assessed in colorectal cancer cell lines and clinical tissues by bisulfite genomic sequencing (BGS), qRT-PCR, and immunoblot assay. Methylation of p75NGFR was frequently found in colorectal cancer, leading to its silencing or downregulation, and it was effectively restored by a demethylation agent. The overexpression of p75NGFR in multiple colorectal cancer cell model systems significantly inhibited cell proliferation (concomitant with G1-phase arrest), invasion, and colony formation and induced cell apoptosis. In contrast, p75NGFR knockdown significantly promoted proliferative and invasive phenotypes. Importantly, p75NGFR methylation was observed in the majority of primary colorectal cancer specimens and was associated with histologic grade and preoperative serum CA19-9 levels. Multivariate analysis indicated that patients who lack p75NGFR have reduced overall survival (64% vs. 75%, P = 0.028) and disease-free survival (61% vs. 72%, P = 0.034) compared with p75NGFR-positive patients. In conclusion, p75NGFR is predominantly silenced or downregulated in colorectal cancer, and its biologic activities are consistent with it being a relevant tumor suppressor. Implications: p75NGFR is a candidate tumor suppressor and has independent prognostic potential in colorectal cancer. Mol Cancer Res; 13(1); 107–19. ©2014 AACR.

Functional variants of -1318T > G and -673C > T in c-Jun promoter region associated with increased colorectal cancer risk by elevating promoter activity

C-Jun plays important roles in the development of multiple cancers, but no well-designed association studies have been conducted to assess the roles of its genetic polymorphisms in cancer risk. In a cohort of 1016 pairs of colorectal cancer (CRC) patients and matched cancer-free controls, we investigated two genetic polymorphisms in the promoter regions of the c-Jun (rs4646999, -673C > T and rs2760501, -1318T > G) via the Taqman assay and evaluated the association between two polymorphisms and risk of CRC. We found that both the -1318G and -673C variant genotypes were associated with an increased risk of CRC [-1318TG: odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.04-1.54; -1318GG: OR = 1.63, 95% CI = 1.03-2.60; -673CT: OR = 1.60, 95% CI = 1.23-2.07; -673CC: OR = 1.80, 95% CI = 1.36-2.37]. Haplotype association analysis showed that compared with the carriers of -1318T-673T haplotype, carriers of the -1318T-673C, -1318G-673T, and -1318G-673C haplotypes all had a significantly increased risk of CRC (P < 0.05 for all). The combined genotypes incorporating both polymorphisms obtained a more significantly additive risk of CRC (one variant genotype: OR = 1.81, 95% CI = 1.30-2.51; two variant genotype: OR = 2.42, 95% CI = 1.70-3.44). Moreover, we found that the change of the -1318T to G allele interact with the -673T to C allele elevated the transcription activity of the c-Jun, and we confirmed the same trends by analyzing c-Jun protein expression in the CRC tissues from patients carrying different number of variant genotypes. This study suggests that -673C > T and -1318T > G genetic variants in c-Jun promoter regions contribute to an increased risk of CRC, possibly by elevating the transcription activity and protein expression levels that appeared to upregulate activity of c-Jun thus tumorigenesis.

Levels of human replication factor C4, a clamp loader, correlate with tumor progression and predict the prognosis for colorectal cancer

BackgroundHuman replication factor C4 (RFC4) is involved in DNA replication as a clamp loader and is aberrantly regulated across a range of cancers. The current study aimed to investigate the function of RFC4 in colorectal cancer (CRC).MethodsThe mRNA levels of RFC4 were assessed in 30 paired primary CRC tissues and matched normal colonic tissues by quantitative PCR. The protein expression levels of RFC4 were evaluated by western blotting (n = 16) and immunohistochemistry (IHC; n = 49), respectively. Clinicopathological features and survival data were correlated with the expression of RFC4 by IHC analysis in a tissue microarray comprising 331 surgically resected CRC. The impact of RFC4 on cell proliferation and the cell cycle was assessed using CRC cell lines.ResultsRFC4 expression was significantly increased in CRC specimens as compared to adjacent normal colonic tissues (P <0.05). High levels of RFC4, determined on a tissue microarray, were significantly associated with differentiation, an advanced stage by the Tumor-Node-Metastasis (TNM) staging system, and a poor prognosis, as compared to low levels of expression (P <0.05). However, in multivariate analysis, RFC4 was not an independent predictor of poor survival for CRC. In vitro studies, the loss of RFC4 suppressed CRC cell proliferation and induced S-phase cell cycle arrest.ConclusionRFC4 is frequently overexpressed in CRC, and is associated with tumor progression and worse survival outcome. This might be attributed to the regulation of CRC cell proliferation and cell cycle arrest by RFC4.