• Asian Pacific Journal of Cancer Prevention
• /
• 제15권20호
• /
• pp.8893-8900
• /
• 2014

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumor development, progression, and carcinogenesis. However, their clinical implications for gastric cancer remain elusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissues from those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNA expression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRTPCR) was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationship between altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Among a total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues from gastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193b and miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Lauren type, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression of miR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regression analysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjusted OR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patients with a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; median survival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; median survival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR-196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-change of up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a may be applied as novel and promising prognostic markers in gastric cancer.

• Molecules and Cells
• /
• 제38권3호
• /
• pp.259-266
• /
• 2015

The regulation of flowering time has crucial implications for plant fitness. MicroRNA156 (miR156) represses the floral transition in Arabidopsis thaliana, but the mechanisms regulating its transcription remain unclear. Here, we show that two AGAMOUS-like proteins, AGL15 and AGL18, act as positive regulators of the expression of MIR156. Small RNA northern blot analysis revealed a significant decrease in the levels of mature miR156 in agl15 agl18 double mutants, but not in the single mutants, suggesting that AGL15 and AGL18 co-regulate miR156 expression. Histochemical analysis further indicated that the double mutants showed a reduction in MIR156 promoter strength. The double mutants also showed reduced abundance of pri-miR156a and pri-miR156c, two of the primary transcripts from MIR156 genes. Electrophoretic mobility shift assays demonstrated that AGL15 directly associated with the CArG motifs in the MIR156a/c promoters. AGL18 did not show binding affinity to the CArG motifs, but pull-down and yeast two-hybrid assays showed that AGL18 forms a heterodimer with AGL15. GFP reporter assays and bimolecular fluorescence complementation (BiFC) showed that AGL15 and AGL18 co-localize in the nucleus and confirmed their in vivo interaction. Overexpression of miR156 did not affect the levels of AGL15 and AGL18 transcripts. Taking these data together, we present a model for the transcriptional regulation of MIR156. In this model, AGL15 and AGL18 may form a complex along with other proteins, and bind to the CArG motifs of the promoters of MIR156 to activate the MIR156 expression.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권3호
• /
• pp.1241-1245
• /
• 2014

Cinobufacin is used clinically to treat patients with many solid malignant tumors. However, the mechanisms underlying action remain to be detailed. Our study focused on miRNAs involved in cinobufacin inhibition of GC cell proliferation. miRNA microarray analysis and real time PCR identified miR-494 as a significant cinobufacin-associated miRNA. In vivo, ectopic expression of miR-494 inhibited the proliferation and induced apoptosis of BGC-823 cells on CCK-8 and flow cytometry analysis. Further study verified BAG-1 (anti-apoptosis gene) to bea target of miR-494 by luciferase reporter assay and Western blotting. In summary, our study demonstrated that cinobufacin may inhibit the proliferation and promote the apoptosis of BGC-823 cells. Cinobufacin-associated miR-494 may indirectly be involved in cell proliferation and apoptosis by targeting BAG-1, pointing to use as a potential molecular target of cinobufacin in gastric cancer therapy.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권21호
• /
• pp.9071-9075
• /
• 2014

Background: microRNAs are small non-coding RNA that control gene expression by mRNA degradation or translational inhibition. These molecules are known to play essential roles in many biological and physiological processes. miR-205 may be differentially expressed in head and neck cancers; however, there are conflicting data and localization of expression has yet to be determined. Materials and Methods: miR-205 expression was investigated in 48 cases of inflammatory, benign and malignant tumor tissue array of the neck, oronasopharynx, larynx and salivary glands by Locked Nucleic Acid in situ hybridization (LNA-ISH) technology. Results: miR-205 expression was significantly differentially expressed across all of the inflammatory, benign and malignant tumor tissues of the neck. A significant increase in miR-205 staining intensity (p<0.05) was observed from inflammation to benign and malignant tumors in head and neck tissue array, suggesting that miR-205 could be a biomarker to differentiate between cancer and non-cancer tissues. Conclusions: LNA-ISH revealed that miR-205 exhibited significant differential cytoplasmic and nuclear staining among inflammation, benign and malignant tumors of head and neck. miR-205 was not only exclusively expressed in squamous epithelial malignancy. This study offers information and a basis for a comprehensive study of the role of miR-205 that may be useful as a biomarker and/or therapeutic target in head and neck tumors.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권8호
• /
• pp.3767-3772
• /
• 2014

Introduction: MicroRNAs have emerged as post-transcriptional regulators that are critically involved in tumorigenesis. This study was designed to explore the effect of miRNA 133b on the proliferation and expression of TBPL1 in colon cancer cells. Methods: Human colon cancer SW-620 cells and human colon adenocarcinoma HT-29 cells were cultured. MiRNA 133b mimcs, miRNA 133b inhibitors, siRNA for TBPL1 and scrambled control were synthesized and transfected into cells. MiR-133b levels in cells and CRC tumor tissue was measured by real-time PCR. TBPL1 mRNA was detected by RT-PCR. Cell proliferation was studied with MTT assay. Western blotting was applied to detect TBPL1 protein levels. Luciferase assays were conducted using a pGL3-promoter vector cloned with full length of 3'UTR of human TBPL1 or 3'UTR with mutant sequence of miR-133b target site in order to confirm if the putative binding site is responsible for the negative regulation of TBPL1 by miR-133b. Results: Real time PCR results showed that miRNA 133b was lower in CRC tissue than that in adjacent tissue. After miR-133b transfection, its level was elevated till 48h, accompanied by lower proliferation in both SW-620 and HT-29 cells. According to that listed in http://www.targetscan.org, the 3'-UTR of TBPL1 mRNA (NM_004865) contains one putative binding site of miR-133b. This site was confirmed to be responsible for the negative regulation by miR-133b with luciferase assay. Further, Western blotting and immunohistochemistry both indicated a higher TBPL1 protein expression level in CRC tissue. Finally, a siRNA for TBPL1 transfection obviously slowed down the cell proliferation in both SW-620 and HT-29 cells. Conclusion: MiR-133b might act as a tumor suppressor and negatively regulate TBPL1 in CRC.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권4호
• /
• pp.1739-1743
• /
• 2014

MicroRNAs are a class of small noncoding RNA which play important regulatory roles in a variety of cancers. MiRNA-specific expression profiles have been reported for several pathological conditions. In this study, we combined large scale parallel Solexa sequencing to identify 11 up-regulated miRNAs and 19 down-regulated miRNAs with computational techniques in the sera of ovarian cancer patients while using healthy serum as the control. Among the above, four miRNAs (miR-22, miR-93, miR-106b, miR-451) were validated by quantitative RT-PCR and found to be significantly aberrantly expressed in the serum of ovarian cancer patients (P<0.05). There were no significant differences between samples from cancer stage I/II and III/IV. However, the levels of miR-106b (p=0.003) and miR-451 (p=0.007) were significantly different in those patients under and over 51 yearsof age. MiR-451 and miR-93 were also specific when analyzed with reference to different levels of CA125. This study shows that Solexa sequencing provides a promising method for cancer-related miRNA profiling, and selectively expressed miRNAs could be used as potential serum-based biomarkers for ovarian cancer diagnosis.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권1호
• /
• pp.161-166
• /
• 2014

Lung cancer is the most common causes of cancer-related deaths worldwide, and a lack of effective methods for early diagnosis has greatly impacted the prognosis and survival rates of the affected patients. Tumor-initiating cells (TICs) are considered to be largely responsible for tumor genesis, resistance to tumor therapy, metastasis, and recurrence. In addition to representing a good potential treatment target, TICs can provide clues for the early diagnosis of cancer. MicroRNA (miRNA) alterations are known to be involved in the initiation and progression of human cancer, and the detection of related miRNAs in TICs is an important strategy for lung cancer early diagnosis. As Hsa-miR-155 (miR-155) can be used as a diagnostic marker for non-small cell lung cancer (NSCLC), a smart molecular beacon of miR-155 was designed to image the expression of miR-155 in NSCLC cases. TICs expressing CD133 and CD338 were obtained from A549 cells by applying an immune magnetic bead isolation system, and miR-155 was detected using laser-scanning confocal microscopy. We found that intracellular miR-155 could be successfully detected using smart miR-155 molecular beacons. Expression was higher in TICs than in A549 cells, indicating that miR-155 may play an important role in regulating bio-behavior of TICs. As a non-invasive approach, molecular beacons could be implemented with molecular imaging to diagnose lung cancer at early stages.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권13호
• /
• pp.5463-5468
• /
• 2014

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권21호
• /
• pp.9185-9190
• /
• 2014

Cyclo-oxygenase-2(Cox-2), a key regulator of inflammation-producing prostaglandins, promotes cell proliferation and growth. Therefore, a better understanding of the regulatory mechanisms of Cox-2 could lead to novel targeted cancer therapies. MicroRNAs are strongly implicated in colorectal cancer but their specific roles and functions have yet to be fully elucidated. MiR-1297 plays an important role in lung adenocarcinoma and laryngeal squamous cell carcinoma, but its significance in colorectal cancer (CRC) has yet to be reported. In our present study, we found miR-1297 to be down regulated in both CRC-derived cell lines and clinical CRC samples, when compared with normal tissues. Furthermore, miR-1297 could inhibit human colorectal cancer LOVO and HCT116 cell proliferation, migration, and invasion in vitro and tumorigenesis in vivo by targeting Cox-2. Moreover, miR-1297 directly binds to the 3'-UTR of Cox-2, and the expression level was drastically decreased in LOVO and HCT116 cells following overexpression of miR-1297. Additionally, Cox-2 expression levels are inversely correlated with miR-1297 expression in human colorectal cancer xenograft tissues. These results imply that miR-1297 has the potential to provide a new approach to colorectal cancer therapy by directly inhibiting Cox-2 expression.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권8호
• /
• pp.3363-3368
• /
• 2014

Background: Curcumin, a phenolic compound extracted from the rhizomes of Curcuma longa, has shown cytotoxic effects against a variety of cancers. The aim of this study was to identify potential microRNA (miRNA) mediators of the anticancer effects of curcumin in ovarian cancer cells. Materials and Methods: SKOV3 ovarian cancer cells were treated with curcumin ($10-60{\mu}M$) and miR-9 expression, cell proliferation, and apoptosis were assessed. The effects of miR-9 depletion on curcumin-mediated growth suppression were also examined. Phosphorylation of Akt and forkhead box protein O1 (FOXO1) was measured in cells with miR-9 overexpression or curcumin treatment. Results: Curcumin caused a significant and dose-dependent increase of miR-9 expression in SKOV3 cells, while significantly impeding cell proliferation and stimulating apoptosis. Depletion of miR-9 significantly (p<0.05) attenuated the growth-suppressive effects of curcumin on SKOV3 cells, coupled with reduced percentages of apoptotic cells. In contrast, overexpression of miR-9 significantly enhanced the cleavage of caspase-3 and poly(ADP-ribose) polymerase and promoted apoptotic death in SKOV3 cells. Western blot analysis showed that both miR-9 overexpression and curcumin similarly caused a significant (p<0.05) decline in the phosphorylation of Akt and FOXO1, compared to untreated cells. Conclusions: The present study provided evidence that curcumin exerts its cytotoxic effects against SKOV3 ovarian cancer cells largely through upregulation of miR-9 and subsequent modulation of Akt/FOXO1 axis. Further studies are needed to identify direct targets of miR-9 that mediate the anticancer effects of curcumin in ovarian cancer cells.