MiR-200c promotes proliferation of papillary thyroid cancer cells via Wnt/β-catenin signaling pathway

OBJECTIVE

To investigate the potential effects of miR-200c on proliferation and apoptosis of papillary thyroid cancer (PTC) cells.

MATERIALS AND METHODS

Micro ribonucleic acid-200c (miR-200c) inhibitor was transfected to down-regulate miR-200c expression. Cell counting kit-8 (CCK-8), colony formation experiment, and flow cytometry were used to detect the effects of miR-200c knockdown on proliferation and apoptosis of Butylated Hydroxytoluene 101 (BHT101) cells. The dual-luciferase reporter gene assay was conducted to detect whether miR-200c directly binds to the target gene. After knocking down miR-200c, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting analysis were performed to detect changes of target genes regarding messenger RNA (mRNA) and protein. Western blotting analysis was also adopted to detect gene expression of Wnt/β-catenin signaling pathway-related proteins.

RESULTS

Compared with those in control group, the proliferation and clone formation ability of BHT101 cells in miR-200c knockdown group were significantly inhibited (p<0.05), while the apoptosis rate increased markedly (p<0.05). Dachshund Family Transcription Factor 1 (DACH1) was the direct target gene of miR-200c. After miR-200c knockdown, the expression levels of Wnt/β-catenin signaling pathway members (including c-Myc, β catenin and cyclin D1) all decreased.

CONCLUSIONS

MiR-200c is a tumor suppressor miRNA, which promotes proliferation of PTC cells and activates Wnt/β-catenin signaling pathway by directly regulating the corresponding target protein, DACH1.

Characterization of ORF127 of Helicoverpa armigera nucleopolyhedrovirus

It has been shown that Ha127 in the genome of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) has homologs in some other baculoviruses and encodes a putative protein of 192 aa. In this study, a sequence analysis showed the transcription initiation site in Ha127 gene at nts 188 upstream of the translation initiation codon ATG and a potential leucine zipper motif at aa 34-55 in the corresponding protein. Ha127 transcripts were detected in HaNPV-infected HzAM1 cells at 18-72 hrs post infection ( p.i.) by RT-PCR, while the corresponding protein was found at 24-72 hrs p.i. by Western blot analysis suggesting that Ha127 is a late gene product. The size of detected Ha127 protein was about 28 K, a larger value than the predicted 22.6 K indicating a post-translational modification. Immunofluorescence assay of HzAM1 cells infected with HaNPV and Ha127-EGFP expression showed that Ha127 protein was localized in the nucleus. In summary, these data suggested that Ha127 was a functional ORF that might play a role in the nucleus during the late or very late gene expression.