LncRNA RP11-436H11.5, functioning as a competitive endogenous RNA, upregulates BCL-W expression by sponging miR-335-5p and promotes proliferation and invasion in renal cell carcinoma
Wang et al. Molecular Cancer
LncRNA RP11-436H11.5, functioning as a competitive endogenous RNA, upregulates BCL-W expression by sponging miR-335-5p and promotes proliferation and invasion in renal cell carcinoma
Kefeng Wang 0
Wei Jin 0
Yan Song 0
Xiang Fei 0
0 Department of Urology, Shengjing Hospital of China Medical University , Shenyang 110004 , China
Background: Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play a crucial role in tumorigenesis. Here, we report a novel lncRNA, RP11-436H11.5, that regulates renal cell carcinoma (RCC) cell proliferation and invasion by sponging miR-335-5p. Methods: Expression of lncRNA RP11-436H11.5 was determined by a qRT-PCR assay in RCC tissues. RCC cell proliferation and invasion were measured by a cell proliferation assay and a transwell invasion assay. Expression of BCL-W was detected by a western blot assay. Interactions between lncRNA RP11-436H11.5 and miR-335-5p were measured by a luciferase reporter assay and a RNA-pull down assay. In vivo experiments were used to detect tumor formation. Results: In this study, the qRT-PCR results illustrated that lncRNA RP11-436H11.5 was more highly expressed in RCC tissues than in adjacent normal renal tissues. The results of survival analysis indicated that patients in the high lncRNA RP11-436H11.5 group presented significantly worse outcomes compared with those in the low lncRNA RP11-436H11.5 group. Downregulation of lncRNA RP11-436H11.5 suppressed RCC cell proliferation and invasion in vitro and in vivo. Luciferase reporter assay results demonstrated that lncRNA RP11-436H11.5 enhanced BCL-W expression by regulating miR-335-5p expression. LncRNA RP11-436H11.5 could function as a miR-335-5p decoy to derepress expression of BCL-W. Conclusions: LncRNA RP11-436H11.5 could function as a competing endogenous RNA to promote RCC cell proliferation and invasion, which might serve as a therapeutic application to suppress RCC progression.
Non-coding RNAs; RP11-436H11; 5; miR-335-5p; Competitive endogenous RNA; Renal cell carcinoma
Background
Renal cell carcinoma (RCC) is the sixth most common
malignant tumor in the United States, representing
approximately 5% of adult male malignancies in 2017
[
1
]. The mortality of RCC patients appears to be
increasing each year, resulting in frequent studies on biological
detections and treatments [
2
]. Drug targeted therapies,
including mammalian targets of rapamycin and vascular
endothelial growth factor, have boomed [
3, 4
].
Unfortunately, drug resistance can occur in late stage patients,
resulting in a bad prognosis [
5, 6
]. Therefore, the
molecular mechanisms of RCC tumorigenesis need to be
thoroughly investigated.
Long non-coding RNAs (lncRNAs) are a set of
nonprotein coding transcripts longer than 200 nucleotides
[
7
]. They have been shown to have various functions
including post-transcriptional regulation, chromatin
modification and other biological processes [
8, 9
]. Some
lncRNAs have been shown to play crucial roles in
different kinds of cancer cells, including breast [10], colorectal
[
11
], gastric [
12
] and renal [
13
] cancer cells.
microRNAs (miRNAs) are also non-coding RNAs
(ncRNAs) that are well known to play important roles in
tumor biological processes [
14, 15
]. Effective diagnostic
and therapeutic strategies have been used in clinical
settings worldwide. Recently, a new mechanism was
discovered in which some lncRNAs and mRNAs could
interact with each other by competing with some
common miRNAs [16]. In this case, lncRNAs could function
as competing endogenous RNA (ceRNA) to sponge
related microRNAs for the derepression of downstream
genes at a post-transcriptional level [
17, 18
]. This
mechanism provides a new way to study ncRNAs in tumors.
Our previous study indicated that miR-335 could
function as a tumor suppressor in RCC. Expression of miR-335
was downregulated in RCC tissues compared to
corresponding normal renal tissues. Low expression of miR-335
was associated with tumor size, lymph node metastasis and
T stage. miR-335 could inhibit proliferation and invasion
through direct suppression of BCL-W [
19
]. Whether
lncRNAs could regulate miR-335 to influence the biological
behaviors of RCC cells has not been characterized.
Here, we first identified a novel lncRNA,
RP11436H11.5, that was more highly expressed in RCC
tissues than in paired normal renal tissues.
Downregulation of lncRNA RP11-436H11.5 could result in
significant suppression of proliferation and invasion in vitro
and in vivo. Our data demonstrated that lncRNA
RP11436H11.5 could directly bind with miR-335-5p and
function as a miRNA decoy to regulate BCL-W expression.
Methods
Clinical samples
Human RCC tissues and adjacent normal renal tissues
were acquired from patients diagnosed with RCC in the
Department of Urology, Shengjing Hospital of China
Medical University. The ethics consents were signed by
each patient before the study. All patients agreed th (...truncated)