Paired Colorectal Cancer Tissues Research Articles

Circular RNA hsa_circ_0000567 can be used as a promising diagnostic biomarker for human colorectal cancer.

Recent studies have revealed that circular RNAs are involved in the biological process of some kinds of human cancers. However, little is known about their diagnostic values and functions in colorectal cancer (CRC). The expression levels of hsa_circ_0000567 in 102 paired CRC tissues and adjacent noncancerous tissues, 5 CRC cell lines, and a normal colorectal epithelial cell line were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The correlations between hsa_circ_0000567 expression levels and the clinicopathological factors of patients with CRC were analyzed. Furthermore, the loss-of-function assay was performed to investigate the functions of hsa_circ_0000567 in vitro. Finally, a receiver operating characteristic (ROC) curve was established to evaluate the diagnostic value of hsa_circ_0000567. Hsa_circ_0000567 expression was significantly downregulated in CRC tissues and CRC cell lines. In addition, the decreased hsa_circ_0000567 expression in CRC was negatively correlated with tumor size (P=.011), lymph metastasis (P=.003), distal metastasis (P<.0001), and tumor-node-metastasis (TNM) stage (P=.003) in CRC. Moreover, knockdown of hsa_circ_0000567 promoted CRC cells proliferation and migration in vitro. Importantly, the area under the ROC curve (AUC) was 0.8653, which indicates hsa_circ_0000567 can serve as a diagnostic biomarker. Hsa_circ_0000567 may be a novel suppressor and a potential diagnosis biomarker in CRC.

The expression profile and clinical significance of circRNA0003906 in colorectal cancer.

Colorectal cancer (CRC) remains a major health problem worldwide and the detailed mechanisms of CRC still need further understanding. Circular RNAs (circRNAs), a special class of endogenous RNAs, have emerged recently as a new potential player in governing fundamental biological process and cancer progression. In this study, we chose circRNA0003906 as a targeted circRNA to evaluate its expression pattern and clinical value in CRC patients. circRNA0003906 expression level in 6 CRC cell lines and 122 paired CRC tissues was measured by quantitative real-time polymerase chain reaction. Then, the potential correlation between circRNA0003906 expression level and clinicopathological factors of CRC patients was analyzed. Additionally, a receiver operating characteristic curve was built to evaluate the diagnostic value of circRNA0003906. Our results showed that circRNA0003906 expression level was dramatically downregulated in both CRC tissues and cell lines. Moreover, the downregulation of circRNA0003906 level significantly correlated with lymphatic metastasis and poor differentiation. In addition, the area under the receiver operating characteristic curve of circRNA0003906 for CRC was 0.818 (P<0.001). Taking consideration of all of these results, circRNA0003906 may be potentially involved in the colorectal cancerogenesis and serve as a potential biomarker for the diagnosis and treatment of CRC.

Low folate metabolic stress reprograms DNA methylation-activated sonic hedgehog signaling to mediate cancer stem cell-like signatures and invasive tumour stage-specific malignancy of human colorectal cancers.

The mechanistic role of colonic low folate metabolic stress (LFMS) in colorectal cancer (CRC) malignancy development remains unknown. Folate analysis on the 99 paired human CRC tissues localized LFMS to the deep invasive T3/T4 staged tumours with hypo-methylated sonic hedgehog (Shh) promoter region and amplified expressions of Shh ligand and Gli1 effector, which coincided with deregulated expressions of the epithelial-mesenchymal transition (EMT) mediators. Colonic folate levels of CRC were inversely correlated with pluripotent expressions of the SOX2, NANOG and OCT4 markers (p < 0.05). Exposure of human colon adenocarcinoma cells to LFMS microenvironment significantly hypomethylated Shh promoter region, activated Shh signaling, induced transcript and protein expressions of the pluripotent markers, promoted trans-differentiation as EMT by deregulation of Snail mediator and epithelial marker E-cadherin, increased MMP2/MMP9 enzymatic digestion on matrix protein for invasion, and promoted self-renewal capability of anchorage-independent tumor-spheroid formation. LFMS-induced cancer stem cell (CSC) signature and CRC invasion is synergized with inhibition of DNA methylation by 5-Aza-2-deoxycytidine (5AZA) in rewiring EMT genotypes, which can be blockade by the Shh inhibitor (cyclopamine). The in vivo and in vitro data corroboratively identify CSC-like molecular targets specific to the LFMS-predisposed invasive CRC through reprogramming DNA methylation-activated Shh signaling. The study highlights CSC targets specific to LFMS-predisposed invasive CRC in optimizing folate co-chemotherapy to minimize tumour metastasis potential of CRC patients.

LncRNA AB073614 regulates proliferation and metastasis of colorectal cancer cells via the PI3K/AKT signaling pathway

The expression profiles of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) have remained unclear. LncRNA AB073614 is known to be upregulated in ovarian cancer and glioma tissues, and is associated with the occurrence and progression of those cancers. In the present study, we investigated the lncRNA AB073614 gene expression patterns in CRC cell lines and tissue samples from CRC patients, and then analyzed them for possible associations with various clinicopathological characteristics. Furthermore, the roles played by lncRNA AB073614 in CRC cell proliferation, apoptosis, cell cycle progression, migration, and invasion were examined in vitro by using gene knockdown and overexpression techniques. We detected the levels of lncRNA AB073614 in 28 paired CRC tissues and adjacent normal tissues by qRT-PCR, and our results revealed that AB073614 expression in 85.7% (24/28) of the CRC tissues was significantly higher than those in the paired normal tissues. Furthermore, the levels of AB073614 were closely related to tumor grade, size, cell differentiation status, and the presence of distant metastases. Knockdown of AB073614 expression significantly inhibited the proliferation, migration, and invasion of SW480 cells, and resulted in their increased rates of apoptosis and G1 phase cell cycle arrest, whereas overexpression of AB073614 produced the opposite effects. Finally, results of studies which used an agonist (740Y-P) and an inhibitor (LY294002) of the PI3K/AKT signaling pathway, as well as the results of western blot assays, indicated that lncRNA AB073614 exerts its effects by targeting the PI3K/AKT-mediated signaling pathway. Taken together, our data indicate that lncRNA AB073614 acts to prevent CRC progression by affecting the PI3K/AKT signaling pathway, and may be useful as a novel prognostic or treatment agent for CRC.

High expression of long non-coding RNA ZEB1-AS1 promotes colorectal cancer cell proliferation partially by suppressing p15 expression

This study aims to investigate the function of long non-coding RNA ZEB1-AS1, reveal its molecular mechanism in colorectal cancer cell growth, and evaluate its clinical significance in colorectal cancer patients. ZEB1-AS1 has reported in the development of several cancers, but the biological role of it in colorectal cancer has not been discussed. In this report, ZEB1-AS1 expression level was measured with quantitative real-time polymerase chain reaction in 63 pairs of colorectal cancer tissues and paired adjacent non-tumor colorectal tissues. The relationship between ZEB1-AS1 expression and overall survival was analyzed by virtue of Kaplan-Meier analysis. Subsequently, small interfering RNA or lentivirus vector-mediated lncRNA ZEB1-AS1 was transfected into colorectal cancer cell lines. Cell viability and apoptosis were examined. Later, nude mouse transplantation experiment was conducted to evaluate the effect of ZEB1-AS1 on colorectal cancer development in vivo. It turns out that ZEB1-AS1 is upregulated in colorectal cancer tissues and its expression is significantly associated with overall survival rate and recurrence-free survival. Upregulation of ZEB1-AS1 colorectal cancer promotes cell proliferation and inhibits cell apoptosis. In addition, cell cycle inhibitory protein p15 participates in the oncogenic function of ZEB1-AS1. Collectively, ZEB1-AS1 has asignificant effect on colorectal cancer pathological process and serves as a valuable prognostic biomarker for colorectal cancer.

Prognostic value of IRF-2 expression in colorectal cancer.

Interferon regulatory factor 2 (IRF-2) is known to play a pivotal role in the development and progression of several malignancies. As a crucial member of interferon regulatory factor family, the association between the expression of IRF-2 and clinical prognostic significance has not been fully explored in colorectal cancer (CRC). The purpose of our study was to investigate the expression profile of IRF-2 in CRC and to examine its association with clinical features. The expression levels of IRF-2 in 18 paired CRC and non-cancerous colorectal tissues were measured by quantitative real-time PCR (qRT-PCR) and those in 4 paired samples by Western blotting. The results showed a significant increase in IRF-2 mRNA expression and protein expression in CRC tissues compared to those in paired normal tissues. Besides, high expression of IRF-2 was significantly associated with distant metastasis (P = 0.041) and preoperative serum CEA level (P = 0.045). Kaplan–Meier survival analysis showed that patients with high expression of IRF-2 had a significantly worse overall survival than those with low expression of IRF-2 (P = 0.006). Further multivariate analysis indicated that IRF-2 and TNM stage were independent prognostic factors for overall survival in patients with CRC. Our study primarily suggests IRF-2 as a potential prognostic biomarker in CRC.

Expression of claudin 1, claudin 4, and claudin 7 in colorectal cancer and its relation with CLDN DNA methylation patterns.

Altered claudin expression has been described in colon, prostatic, ovarian, and breast carcinoma. However, the role of epigenetic modifications in these genes and their role in colorectal cancer is unknown. We aimed our study to investigate whether claudin protein expression and methylation of CLDN can influence the tumorigenesis of colorectal cancer. A total of 31 patients diagnosed with colorectal carcinoma was used in this study. Immunohistochemical staining was used to study protein expression in both tumor and the adjacent nonneoplastic mucosa of claudin 1, 4, and 7. To detect the DNA methylation pattern of CLDN1, 4, and 7, genomic DNA was extracted from both the tumor and the adjacent nonneoplastic mucosa. Methylation analysis was carried out using bisulfite pyrosequencing. Cell membrane staining intensity of all claudins was found significantly lower in colorectal cancer tissues when compared to paired normal mucosa (p ≤ 0.001). For claudin 4, the percentage of cells staining positively was also significantly reduced (p = 0.04). In normal mucosa, cytoplasm showed no staining for claudins in any patient, whereas in paired colorectal cancer tissues, significant cytoplasmic staining appeared both for claudin 1 (p = 0.04) and claudin 4 (p = 0.01). Tumor samples were significantly hypomethylated in CLDN1 (p < 0.05). In conclusion, our results show that CLDN1 is significantly hypomethylated in tumor samples and that the membrane staining intensity for claudin 1, 4, and 7 is significantly lower in colorectal cancer tissues than in adjacent nonneoplastic tissue. Colorectal cancer cells showed dystopic cytoplasmic location of claudins.

Comprehensive profile of differentially expressed circular RNAs reveals that hsa_circ_0000069 is upregulated and promotes cell proliferation, migration, and invasion in colorectal cancer.

BackgroundNowadays, despite great progress in cancer research, the detailed mechanisms of colorectal cancer (CRC) are still poorly understood. Circular RNAs (circRNAs), a new star of the non-coding RNA network, have been identified as critical regulators in various cancers, including CRC.Methods and resultsIn this study, by using unsupervised hierarchical clustering analysis, a novel dysregulated circRNA, hsa_circ_0000069, was found. The expression of hsa_circ_0000069 was measured in 30 paired CRC tissues and adjacent noncancerous tissues using quantitative polymerase chain reaction. A high expression of hsa_circ_0000069 was observed in CRC tissues and correlated with patients’ age and tumor, node, metastasis (TNM) stage (P<0.05). Furthermore, by using specifically designed siRNAs in CRC cells, a functional analysis was performed which revealed that hsa_circ_0000069 knockdown could notably inhibit cell proliferation, migration, and invasion, and induce G0/G1 phase arrest of cell cycle in vitro.ConclusionThis study’s findings are the first to demonstrate that hsa_circ_0000069, an important regulator in cancer progression, could be a promising target in the diagnosis and therapy in colorectal cancer.

MiR-448 suppresses E2F3 to inhibit proliferation and induce apoptosis in human colorectal cancer cells

Background: Colorectal cancer (CRC) is one of the most common malignancies over the world, and recent studies have demonstrated that microRNAs are implicated in the carcinogenesis of CRC. Here we analyzed the expression of miR-448 in CRC tumor samples and studied its function and mechanism in regulating proliferation and apoptosis in CRC cells. Methods: Thirty-four paired CRC tissues and normal adjacent tissues were analyzed for miR-448 and E2F3 expression using Real-time PCR. Endogenous miR-448 was modulated by transfection of miR-448 mimics or inhibitor. Cell proliferation was determined by cell viability assay and BrdU proliferation assay. Changes of apoptosis after miR-448 transfection were determined by caspase-3 activity assay, TUNEL assay and western blot assay for cleaved-PARP expression. Luciferase reporter assay was used to validate whether miR-448 targets E2F3. Results: We found that miR-448 expression was significantly down-regulated in CRC tissues, which is constantly associated with up-regulation of E2F3 expression. Overexpression of miR-448 in CRC cell line restricted cell proliferation and induced apoptosis, whereas inhibition of miR-448 had opposite effects on cell proliferation and apoptosis. E2F3 functions as a direct target of miR-448, and overexpression of E2F3 cancelled the effects of miR-448 on cell proliferation and apoptosis. Conclusions: We conclude that miR-448 is downregulated in CRC and functions to suppress tumor cell growth by targeting E2F3, and miR-448 could be a potential therapeutic target for CRC.

The investigation of functions of metastasis associated lung adenocarcinoma transcript 1 in migration/invasion of colorectal cancer cells

Objective To investigate the expression and clinical value of long non-coding RNA MALAT1 in colorectal cancer tissues. We also set to interpret the roles and the possible mechanismsof MALAT1 in cell migration/invasion of colorectal cancer cells. Methods Real-time quantitative polymerase chain reaction (Real-time PCR) was applied to examine the expression of MALAT1 in paired colorectal cancer tissues and normal tissues. MALAT1 was knocked down by small interfering RNA (siRNA) in SW620 cells. Wound healing and transwell assay were performed to evaluate the effects of MALAT1 on the migration and invasion abilities respectively. Western blotting was finally used to detect the expression of epithelial-mesenchymal transition (EMT) markers. Results MALAT1 was significantly increased in colorectal cancer tissues. MALAT1 was up-regulated in colorectal cancer tissue compare 46.7% (14/30) compared with normal tissue with statistical difference (P<0.05); Transient inhibition of MALAT1 in SW620 cells resulted in decreased cell migration/invasion. The expression of EMT markers were down-regulated after MALAT1 was knocked down. Conclusion Up-regulation of MALAT1 in colorectal promotes cell migration/invasion, which might be mediated by inducing EMT. Key words: Metastasis-associated lung adenocarcinoma transcript 1; Colorectal cancer; Neoplasm metastasis; Epithelial-mesenchymal transition

Upregulation of long noncoding RNA ZFAS1 predicts poor prognosis and prompts invasion and metastasis in colorectal cancer

PurposeZFAS1 is a newly identified long non-coding RNA. The present study investigated the relationships of ZFAS1 expression with clinicalpathologic parameters and the prognosis of patients with colorectal cancer (CRC). The effects of ZFAS1 on cell migration, invasion and metastasis were also been evaluated in CRC cell lines. MethodsA total of 159 paired primary CRC tissues and adjacent noncancerous tissues (NCTs) were collected and were tested for the expression of ZFAS1. Cell migration and invasion were measured by wound-healing and Transwell assays, respectively. Tumor metastasis was assessed using a lung metastasis model of nude mouse. ResultsThe ZFAS1 expression was significantly upregulated in 47.8% (76 of 159) of cancerous tissues compared with NCTs(p<0.0001), and was higher in metastatic tumors than in corresponding primary CRC tumors (p=0.010). ZFAS1 expression in CRC was positively correlated with lymphatic invasion (p=0.045) and TNM stage (p=0.003). Patients with increased ZFAS1 expression showed shorter relapse-free survival and overall survival (p<0.05). Cox multivariate analyses confirmed that ZFAS1 expression is an independent prognostic factor in CRC (p<0.05). The knockdown of ZFAS1 decreased cell migration and invasive ability of LoVo and HCT116 cells in vitro (p<0.05). Moreover, silencing ZFAS1 expression inhibited the in vivo metastasis of CRC cells (p<0.05). ConclusionsThe expression of ZFAS1 is positively correlated with TNM stage and appears to be a new prognostic factor in CRC. ZFAS1 promptes cell migration, invasive and metastasis ability of CRC cells.

LncRNA DQ786243 contributes to proliferation and metastasis of colorectal cancer both invitro and invivo.

Accumulating evidence demonstrates that long non-coding RNAs (LncRNAs) play important roles in regulating gene expression and are involved in various cancers, including colorectal cancer (CRC). However, LncRNA profiles in CRC remain largely unknown. The present study aims to find the key LncRNA associated with CRC and to study its biological functions in CRC progression. We focused on LncRNA DQ786243, one of LncRNAs which promoted development of CRC from the Gene Expression Omnibus (GEO) and validated using quantitative real-time PCR among about 20 paired CRC tissues. The effects of LncRNA DQ786243 were assessed by silencing the LncRNA invitro and invivo Results showed that the expression level LncRNA DQ786243 was significantly higher in CRC tissues and cell lines. We also found LncRNA DQ786243 knockdown by RNA interference with siRNA significantly arrested the cell cycle in the G2/M-phase, promoted apoptosis and weaken the abilities of cell proliferation and invasion invitro Further investigation into the mechanisms responsible for the growth inhibitory effects by DQ786243 silencing revealed that its knockdown resulted in the induction of cell cycle arrest and apoptosis through certain cell cycle-related and apoptosis-related proteins. Finally, xenograft experiments confirmed that the growth of xenograft tumours formed by CRC cells was suppressed after silencing LncRNA DQ786243 expression. In conclusion, the present study suggests that LncRNA DQ786243 is an oncogene that promotes tumour progression and leads us to propose that LncRNAs may serve as key regulatory hubs in CRC progression.

Epigenetic silencing of miR-181b contributes to tumorigenicity in colorectal cancer by targeting RASSF1A.

Aberrant microRNA expression is common in colorectal cancer and DNA methylation is believed to be responsible for this alteration. In this study, we performed evaluation in vivo and in vitro to determine the role of miR-181b as a potential diagnostic and prognostic biomarker in colorectal cancer. Ninety-seven pairs of colorectal cancer tissues and adjacent normal tissues were collected. The expression level and methylation status of miR-181b was determined in tissue samples and multiple colorectal cancer cell lines. RASSF1A, a predicted target gene of miR-181b, was investigated in vitro. Further mechanistic explorations were conducted. It was found that miR-181b expression was frequently downregulated in cancer samples. This lower expression level resulted from higher hypermethylation in cancer tissue and was closely related to TNM stage. Following artificial synthesis of miR-181b stimulation, colorectal cancer cell proliferation was greatly inhibited in CRC cells while apoptosis percentage markedly increased. miR-181b achieved the tumor suppressive effects via direct targeting of the RASSF1A gene. This study indicated the clinical significance of miR-181b and the influence of miR-181b promoter region in epigenetic silencing of tumorigenicity in colorectal cancer, and implied the possible usage of miR-181b as a diagnostic and prognostic biomarker in colorectal cancer.

Decreased expression of miR-132 in CRC tissues and its inhibitory function on tumor progression

AbstractObjectives Colorectal cancer (CRC) is among the most common types of malignancies in the worldwide, and microRNAs (miRNAs) emerge as key regulators in carcinogenesis and tumor progression. Here we intended to address the expression and function of miR-132 in CRC cells. Methods Paired CRC tissues and several established cell lines were firstly collected. We performed qPCR to detect the expression of miR-132 in these tissues and cell lines. Cell proliferation and apoptosis were respectively monitored by CCK-8 assay and Annexin-V/PI staining followed by flow cytometry, after miR-132 was transiently overexpressed in RKO cells. Afterwards, Luciferase reporter assays were performed to examine the targeting of YAP1 by miR-132. Finally, qPCR and western blotting were also carried out to validate this targeting. Results MiR-132 was significantly decreased in CRC and its overexpression in RKO cells exerted tumor suppressing effects, including cell growth arrest and apoptosis promotion. Additionally, we proved that miR-132 could negatively regulate the expression of YAP1. Conclusion Our findings suggested that miR-132 was downregulated in CRC, and played as a tumor suppressor to inhibit cell proliferation and induce apoptosis. And these anti-tumor activities might be related with the targeting of YAP1 by miR-132.

Prognostic value of regulator of G-protein signaling 6 in colorectal cancer.

Reprogrammed metabolism is a hallmark of cancer cells. Regulator of G-protein signaling 6 (RGS6), which is frequently down-regulated in multiple human malignancies, has been demonstrated to play a critical function in energy metabolism, cell apoptosis and tumorigenesis. However, limited knowledge is known about the expression pattern and prognostic value of RGS6 in colorectal cancer (CRC). In this study, we first observed that RGS6 mRNA and protein is commonly downregulated in 32 paired CRC tissues compared with their normal counterparts. Furthermore, by a large scale of immunohistochemical analysis in a tissue microarray containing 310 cases of CRC specimens, we demonstrated that the protein expression of RGS6 expression is downregulated in 40.97% (127/310) samples and detected that decreasing RGS6 expression is closely correlated with enhanced tumor size, CEA level, T classification, TNM stage, and easier lymphatic and distant metastasis. Meanwhile, Kaplan-Meier survival analysis showed that CRC patients with a lower RGS6 expression have a poorer clinical outcome than those with a higher RGS6 expression. Multivariate Cox regression analysis revealed that RGS6, lymphatic metastasis and distant metastasis are the independent prognostic factors for overall survival rate of CRC patients. Taken together, our studies reveal the prognostic value of RGS6 in CRC and support that RGS6 may act as a molecular target for CRC treatment.

GRIM-19 expression is a potent prognostic marker in colorectal cancer

Retinoid-interferon-induced mortality-19 (GRIM-19), a recently discovered cell death regulatory gene, may function as a tumor suppressor in many human malignancies. However, the expression of GRIM-19 in and its prognostic value for patients with colorectal cancer (CRC) have not been well investigated to date. Here, GRIM-19 expression was measured immunohistochemically in 94 colon samples and by quantitative real-time reverse transcriptase polymerase chain reaction in 15 paired CRC tissues and adjacent normal tissues. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests. Our results showed that GRIM-19 mRNA and protein levels in adenoma tissues were similar to those in adjacent normal tissues. However, GRIM-19 expression was severely depressed in carcinomas compared to matched normal tissues (P = .000). Additionally, we found GRIM-19 to be located in both the cytoplasm and nucleus in normal tissues but only in the cytoplasm in CRC tissues. Alteration in GRIM-19 expression occurs early in the pathogenesis of CRC; moreover, low GRIM-19 expression was associated with poor tumor differentiation (P = .013), the presence of lymph nodes (P = .000), metastasis to other organs (P = .045) and vascular invasion (P = .010). During a mean period of 40 months follow-up, patients without GRIM-19 had a statistically significantly lower rate of recurrence/metastasis (P < .05) and a shorter overall survival time (P < .01) than the patients with GRIM-19 expression. Taken together, GRIM-19 expression is closely associated with CRC progression and might be a very promising prognostic biomarker for CRC patients.

Screening of potential diagnostic markers and therapeutic targets against colorectal cancer.

ObjectiveTo identify genes with aberrant promoter methylation for developing novel diagnostic markers and therapeutic targets against primary colorectal cancer (CRC).MethodsTwo paired CRC and adjacent normal tissues were collected from two CRC patients. A Resi: MBD2b protein-sepharose-4B column was used to enrich the methylated DNA fragments. Difference in the average methylation level of each DNA methylation region between the tumor and control samples was determined by log2 fold change (FC) in each patient to screen the differentially methylated DNA regions. Genes with log2FC value ≥4 or ≤−4 were identified to be hypermethylated and hypomethylated, respectively. Then, the underlying functions of methylated genes were speculated by Gene Ontology database and pathway enrichment analyses. Furthermore, a protein–protein interaction network was built using Search Tool for the Retrieval of Interacting Genes/Proteins database, and the transcription factor binding sites were screened via the Encyclopedia of DNA Elements (ENCODE) database.ResultsTotally, 2,284 and 1,142 genes were predicted to have aberrant promoter hypermethylation or hypomethylation, respectively. MAP3K5, MAP3K8, MAPK14, and MAPK9 with promoter hypermethylation functioned via MAPK signaling pathway, focal adhesion, or Wnt signaling pathway, whereas MAP2K1, MAPK3, MAPK11, and MAPK7 with promoter hypomethylation functioned via TGF-beta signaling pathway, neurotrophin signaling pathway, and chemokine signaling pathway. CREBBP, PIK3R1, MAPK14, APP, ESR1, MAPK3, and HRAS were the seven hubs in the constructed protein–protein interaction network. RPL22, RPL36, RPLP2, RPS7, and RPS9 were commonly regulated by transcription factors, and YY1 and IRF4 were hypermethylated.ConclusionMAPK14, MAPK3, HRAS, YY1, and IRF4 may be considered as potential biomarkers for early diagnosis and therapy of CRC.

MicroRNA-217 functions as a prognosis predictor and inhibits colorectal cancer cell proliferation and invasion via an AEG-1 dependent mechanism.

BackgroundRecent studies have indicated the possible function of miR-217 in tumorigenesis. However, the roles of miR-217 in colorectal cancer (CRC) are still largely unknown.MethodsWe examined the expression of miR-217 and AEG-1 in 50 CRC tissues and the corresponding noncancerous tissues by qRT-PCR. The clinical significance of miR-217 was analyzed. CRC cell lines with miR-217 upregulation and AEG-1 silencing were established and the effects on tumor growth in vitro and in vivo were assessed. Dual-luciferase reporter gene assays were also performed to investigate the interaction between miR-217 and AEG-1.ResultsOur data demonstrated that miR-217 was significantly downregulated in 50 pairs of colorectal cancer tissues. MiR-217 expression levels were closely correlated with tumor differentiation. Moreover, decreased miR-217 expression was also associated with shorter overall survival of CRC patients. MiR-217 overexpression significantly inhibited proliferation, colony formation and invasiveness of CRC cells by promoting apoptosis and G0/G1 phase arrest. Interestingly, ectopic miR-217 expression decreased AEG-1 expression and repressed luciferase reporter activity associated with the AEG-1 3′-untranslated region (UTR). AEG-1 silencing resulted in similar biological behavior changes to those associated with miR-217 overexpression. Finally, in a nude mouse xenografted tumor model, miR-217 overexpression significantly suppressed CRC cell growth.ConclusionsOur findings suggest that miR-217 has considerable value as a prognostic marker and potential therapeutic target in CRC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1438-z) contains supplementary material, which is available to authorized users.

Regenerating Gene 1B Silencing Inhibits Colon Cancer Cell HCT116 Proliferation and Invasion

The human regenerating gene 1B (REG1B) is found to be frequently up-regulated in many types of human tumors. It is unclear whether REG1B expression may have therapeutic value in colorectal carcinoma. Additionally, how REG1B is associated with the clinical features of colorectal carcinoma is not known. To investigate the relationship between REG1B and colorectal cancer, we analyzed REG1B expression in clinical specimens and cell lines and the effect of down-regulation of REG1B by short hairpin RNA (shRNA) in HCT116 cells. Paraffin-embedded specimens from 30 pairs of colorectal cancer tissues and adjacent colon tissues were used to investigate the expression of REG1B by immunohistochemistry. We also examined whether REG1B itself may be related to cell proliferation, cell cycle arrest, apoptosis, migration and invasion in colon cancer HCT116 cells. Our results showed that REG1B was highly expressed in colorectal carcinoma and was significantly associated with cell differentiation status. The results also illustrated that REG1B silencing with shRNA inhibited cell proliferation, migration and invasion but did not induce apoptosis. Furthermore, down-regulation of REG1B induces G1-phase cell cycle arrest in colon cancer cells. Knockdown of REG1B can inhibit cell proliferation, migration and invasion. It may act by a mechanism regulating cell cycle progression. Thus, REG1B may be a novel candidate therapeutic target for colorectal cancer.

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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-014-0320-0) contains supplementary material, which is available to authorized users.