MiR-193a-3p and miR-193a-5p suppress the metastasis of human osteosarcoma cells by down-regulating Rab27B and SRR, respectively
Clin Exp Metastasis
MiR-193a-3p and miR-193a-5p suppress the metastasis of human osteosarcoma cells by down-regulating Rab27B and SRR, respectively
Youguang Pu 0 1 2 3 4
Fangfang Zhao 0 1 2 3 4
Wenjing Cai 0 1 2 3 4
Xianghui Meng 0 1 2 3 4
Yinpeng Li 0 1 2 3 4
Shanbao Cai 0 1 2 3 4
0 Indiana University School of Medicine , Indianapolis, IN 46202 , USA
1 Cancer Epigenetics Program, Anhui Cancer Hospital , Hefei 230031, Anhui , China
2 & Shanbao Cai
3 Xinxiang Medical University , Xinxiang 453000, Henan , China
4 Department of Orthopedic Surgery, Anhui Cancer Hospital , Hefei 230031, Anhui , China
MicroRNAs have been identified as key players in the development and progression of osteosarcoma, which is the most common primary malignancy of bone. Sequencing-based miR-omic and quantitative real-time PCR analyses suggested that the expression of miR-193a3p and miR-193a-5p was decreased by DNA methylation at their promoter region in a highly metastatic osteosarcoma cell line (MG63.2) relative to their expression in the less metastatic MG63 cell line. Further wound-healing and invasion assays demonstrated that both miR-193a-3p and miR-193a-5p suppressed osteosarcoma cell migration and invasion. Moreover, introducing miR-193a-3p and miR193a-5p mimics into MG63.2 cells or antagomiRs into MG63 cells confirmed their critical roles in osteosarcoma metastasis. Additionally, bioinformatics prediction along with biochemical assay results clearly suggested that the secretory small GTPase Rab27B and serine racemase (SRR) were direct targets of miR-193a-3p and miR-193a5p, respectively. These two targets are indeed involved in the miR-193a-3p- and miR-193a-5p-induced suppression of osteosarcoma cell migration and invasion. MiR-193a-3p and miR-193a-5p play important roles in osteosarcoma metastasis through down-regulation of the Rab27B and SRR genes and therefore may serve as useful biomarkers for the diagnosis of osteosarcoma and as potential candidates for the treatment of metastatic osteosarcoma.
Rab27B; SRR; MiR-193a-3p and miR-193a-; 5p; Osteosarcoma; Metastasis
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Youguang Pu and Fangfang Zhao have contributed equally to this
work.
Introduction
Osteosarcoma is the most common primary bone
malignancy in children and young adults [
1, 2
]. Approximately
80 % of osteosarcoma patients have metastatic disease at
the time of diagnosis, and metastasis is a consistent
problem in tumor prognosis and treatment [3]. The molecular
mechanisms that lead to the development and metastasis of
osteosarcoma are poorly understood [
4–6
]. Further
exploration of this area will help in the development of effective
strategies in the diagnosis, treatment and prognosis of
osteosarcoma. Previous studies have established a highly
tumorigenic and metastatic human osteosarcoma cell line,
MG63.2, derived from the less metastatic parental MG63
cell line [
7
]. The MG63.2 cell line facilitates the
exploration of crucial players in osteosarcoma metastasis [
8
].
MicroRNAs (miRNAs), a class of small non-coding
RNA molecules, play critical roles in a variety of
biological events, including development, cell proliferation and
cell differentiation [
9–11
]. MiRNAs negatively regulate
gene expression by binding to the 30-untranslated regions
(UTRs) of the corresponding target mRNAs of
proteincoding genes, thereby leading to mRNA degradation or
translation inhibition [
12–15
]. Multiple miRNAs are
involved in the invasion and metastasis of different types of
cancers, including gastric cancer, breast cancer,
hepatocellular carcinoma and colorectalcancer [
16–19
]. In
osteosarcoma, a few miRNAs have been reported to
regulate metastasis. For instance, miR-16 inhibits cell
proliferation by targeting IGF1R and the Raf1-MEK1/2-ERK1/2
pathway in osteosarcoma [
20
], and miR-802 promotes
osteosarcoma cell proliferation by down-regulating the p27
cell-cycle inhibitor [
21
]. Moreover, miR-212 inhibits
osteosarcoma cell proliferation and invasion by
downregulating Sox4 [
22
]. However, the prospects of these
miRNAs in the clinical treatment of osteosarcoma have not
been evaluated. Novel miRNAs that may potentially serve
as new therapeutic targets or biomarkers must urgently be
identified.
In the present study, we aimed to identify novel
miRNAs associated with osteosarcoma metastasis. From a
sequencing-based miR-omic study and referred to the
relevant literatures, we found two miRNAs, miR-193a-3p and
miR-193a-5p, that play a role in osteosarcoma metastasis.
These two miRNAs, which are derived from the same
precursor, have different sequences and therefore target
different mRNAs [
23
]. These miRNAs have been
implicated in the tumorigenesis and progression of several types
of cancer [
24–28
]. In addition, we identified the target
genes of miR-193a-3p and miR-193a-5p, and we proposed
the potential pathway that might be associated with
osteosarcoma metastasis. Therefore, miR-193a-3p and
miR-193a-5p, as well as their targets, might serve as (...truncated)