miR-16 targets SALL4 to repress the proliferation and migration of gastric cancer

Abstract

There is increasing evidence that microRNAs (miRNAs) play important roles in tumor progression and development by targeting different genes, including gastric cancer (GC). However, the role of miR-16 in GC is so far unclear. Herein, we examined the function and potential mechanism of miR-16 in GC. Reverse transcription-quantitative PCR found that miR-16 expression was prominently lower in GC tissues while SALL4 expression was frequently higher than normal tissues. Re-expression of miR-16 could suppress GC cell proliferation and migration by MTT and Transwell assay. We confirmed that miR-16 directly targeted SALL4 in regulating GC by luciferase assay. Knockdown of SALL4 inhibited cell proliferation and migration. Furthermore, SALL4 could counteract the inhibition-effect of miR-16 in GC. In conclusion, for the the first time we demonstrated that miR-16 played inhibitory effect through targeting SALL4 in GC cell proliferation and migration. Our study revealed that miR-16/SALL4 axis was critical in regulating the GC development, indicating a new prospect to regulate GC cell progression and development.

Keywords: SALL4; gastric cancer; miR-16; migration; proliferation; repress.

Figure 1.

Decrease of miR-16 and increase of SALL4 in GC. (A) miR-16 expression in 40 paired GC tumor and normal tissues. (B) Differential expression of miR-16 in stage I/II and stage III/IV of GC tumor. (C) miR-16 expression in GC cells and normal GES-1 cells. (D and E) SALL4 mRNA and protein expression in GC tissues. (F and G) SALL4 mRNA and protein expression in GC cells and GES-1 cells. *P<0.05, **P<0.01, ***P<0.001.

Figure 2.

Abnormal expression of miR-16 affects the proliferation and migration ability of GC. (A and B) miR-16 expression increased observably in miR-16 mimic group, while decreased in miR-16 inhibitor group in both GC cell lines. (C and D) GC cell viability in the cell lines examined by MTT assays after overexpression or knockdown of miR-16. (E and F) GC cell migration in the cell lines examined by Transwell assays after overexpression or knockdown of miR-16. *P<0.05, **P<0.01, ***P<0.001; ^#P<0.05, ^##P<0.01.

Figure 3.

Inhibitory effect of SALL4 siRNA on GC cell proliferation and migration. (A) SALL4 protein content in SGC-7901 and HGC-27 cell lines after downregulation SALL4. (B) SALL4 mRNA content in SGC-7901 and HGC-27 cell lines after downregulation of SALL4. (C) GC cell viability in two cell lines examined by MTT assay after silencing SALL4. (D) GC cell migration in the cell lines examined by Transwell assay after silencing SALL4. *P<0.05, **P<0.01, ***P<0.001.

Figure 4.

Corroboration of SALL4 as the target of miR-16 in GC. (A) The binding sites of miR-16 with the 3′-UTR of SALL4. (B) Relative luciferase activities in GC cells after treated with miR-16 mimic. (C) Relative SALL4 mRNA expression in the GC cell lines after miR-16 overexpression or silence. (D) Relative SALL4 protein expression in the GC cell lines after miR-16 overexpression or silence. **P<0.01, ***P<0.001; ^##P<0.01, ^###P<0.001.

Figure 5.

Reversal effect of SALL4 on GC cell proliferation and migration regulated by miR-16. (A and B) Quantitative cell viability in GC cells treated with both miR-16 mimic and SALL4 vector or miR-16 mimic by MTT assays. (C and D) Image showcasing and quantitative cell migration in GC cells after treatment with both miR-16 mimic and SALL4 vector or miR-16 mimic alone by Transwell migration assays. *P<0.05, **P<0.01, ***P<0.001; ^#P<0.05, ^##P<0.01.