Dataset Information

MiR-26a and its target CKS2 modulate cell growth and tumorigenesis of papillary thyroid carcinoma.

ABSTRACT:

Background

While many studies have shown that levels of miR-26a are lower in papillary thyroid carcinoma (PTC), the role and mechanism of miR-26a in PTC are unclear.

Method

We used database searches to select potential mRNA targets of miR-26a. Anti-miR-26a, miR-26a mimic, siRNA for CKS2 and their effects on cell growth, cell-cycle distribution and colony formation were evaluated. We also evaluate the over-expressed miR-26a in TPC-1 cells in severe combined immune-deficient mice. We used luciferase reporter assays, real-time PCR and western blot analysis to measure the expression and activity of miR-26a, CKS2, and related factors such as cyclin B1, cyclin A, cdk1, bcl-xl and Akt. Finally, we measured the relationship between the levels of miR-26a and CKS2 in PTC and normal thyroid tissues.

Results

Relative to normal thyroid tissues, miR-26a is consistently down-regulated in TPC specimens, and CKS2 was identified as a potential target. Up-regulated miR-26a expression or down-regulated CKS2 expression in TPC-1 and CGTH W3 cells lines caused G2 phase-arrest. Decreased miR-26a expression or increased CKS2 expression could have inverse function on PTC cell lines. CyclinB1, cyclinA, bcl-xl and AKt are indirectly regulated by miR-26a in a CKS2-dependent manner. Finally, CKS2 is overexpressed in PTC specimens relative to normal thyroid tissue, and a significant inverse correlation exists between miR-26a and CKS2 expression in clinical PTC specimens.

Conclusion

Our data indicate that miR-26a functions as a growth-suppressive miRNA in PTC, and that its suppressive effects are mediated mainly by repressing CKS2 expression.

SUBMITTER: Lv M

PROVIDER: S-EPMC3702500 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Papillary thyroid carcinoma (PTC) is the most common endocrine cancer with a significantly increase of the incidence recently. Several cytokines, such as thyroid peroxidase (TPO), cluster of differentiation 56 (CD56), Galectin-3, mesothelial cell (MC), cytokeratin 19 (CK19) and BRAF (B-raf) were recommended to be tested by immunohistochemistry (IHC) for a definitive diagnosis, but were still limited in clinical use because of their relative lower sensitivity and specificity. MicroRNA (miRNA), as a new molecular biomarkers, however, has not been reported yet so far. To address this, hsa-miR-200a-5p, a miRNA, was selected and detected in PTC patients by in situ hybrization with benign thyroid tumor with papillary hyperplasia as a control, and the differential expression of hsa-miR-200a-5p between fresh PTC tissues and control was detected by qRT-PCR. Expressive levels of cytokines of TPO, CD56, Galectin-3, MC, CK19 and B-raf were also detected by immunohistochemistry. The correlation was analyzed by SPSS software using Spearman methods. As expected, the hsa-miR-200a-5p expressive level was significantly increased in PTC patients, compared to that of control, and was consistent with that of TPO, CD56, Galectin-3, MC, CK19 and B-raf. In addition, expression of hsa-miR-200a-5p showed negative correlation to that of TPO (rs = - 0.734; **: P < 0.01) and CD56 (rs = - 0.570; **: P < 0.01), but positive correlation to that of Galectin-3 (rs = 0.601; **: P < 0.01), MC (rs = 0.508; **: P < 0.01), CK19 (rs = 0.712; **: P < 0.01) and B-raf (rs = 0.378; **: P < 0.01). PTC and papillary benign thyroid papillary hyperplasia are difficult to distinguish in morphology, so requiring immunohistochemistry to further differentiate the diagnosis, however, for the existing clinical common diagnostic marker for immunohistochemistry, the sensitivity and accuracy are low, it is easy to miss diagnosis. Therefore, there is an urgent need for a rapid and sensitive molecular marker. So miR-200a-5p can be used to assist in the diagnosis of PTC at the molecular level, and as a biomarker, can be effectively used to distinguish between PTC and benign thyroid tumor with papillary hyperplasia.