FLOT1 adenovirus

The microRNA miR-485-5p was previously reported to be a negative regulator of tumorigenesis in breast cancer and hepatocellular carcinoma, and differential expression of miR-485-5p has been observed between CC and normal control tissues. Here, researchers confirmed that miR-485-5p expression was lower in CC than in adjacent normal tissues and went on to investigate the effects of miR-485 on tumor behavior in CC cell lines. miR-485-5p transcription was reduced in HPV-infected CC tissues, and miR-485 levels in clinical samples were positively correlated with 5-year overall survival. Transwell assays showed that miR-485-5p inhibited cell invasion and migration, but had no effect on apoptosis and cell proliferation. Using a luciferase reporter assay, researchers demonstrated that miR-485-5p partially abolished cell migration and proliferation by targeting FLOT-1 mRNA. Transfection of HPV-infected cervical cancer cells with adenoviral vector encoding human FLOT-1 partially attenuated the inhibitory effect of miR-485 on cell invasion. Taken together, these data suggest that miR-485-5p inhibits cancer cell invasion by targeting FLOT-1 in HPV-infected cervical cancer cells.

The proliferation capacity of HPV16-infected and non-HPV-infected cervical cancer cell lines after treatment with miR-485-5p was detected by MTT assay. The researchers found that miR-485-5p inhibited the proliferation of HPV-infected cell lines (Figure 1A). However, it had no effect on the proliferation of non-HPV-infected cervical cancer cell lines (Figure 1B). The transfection efficiency of scramble and FLOT-1 overexpression groups based on GFP fluorescence is shown in Figure 1C. HPV-infected cell lines were transfected with pcDEF3 vector encoding human FLOT-1 protein, and they were treated with miR-485 mimics at the same time. Exogenous introduction of adenoviral vectors encoding FLOT-1 increased the expression of FLOT-1, although cell proliferation in HPV-infected cell lines was still reduced (Figure 1D, E), indicating that the downregulation of cell proliferation of HPV-infected cell lines by miR-485 may not be related to the degradation of FLOT-1 mRNA. These results suggest that miR-485-5p may have multiple gene targets to regulate tumor behavior.

Figure 1. miR-485-5p had a negative influence on cell proliferation independent of the expression of FLOT-1 in HPV-infected cell lines. (Dai Y, Xie F, Chen Y., 2020)