Dysregulated expression and functions of microRNA-330 in cancers: A potential therapeutic target

As small non-coding RNAs, MicroRNAs (miRNAs) bind to the 3' untranslated region (3'-UTR) of mRNA targets to control gene transcription and translation. The gene of miR-330 has two miRNA products, including miR-330-3p and miR-330-5p, which exhibit anti-tumorigenesis and/or pro-tumorigenesis effects in many kinds of malignancies. In cancers, miR-330-3p and miR-330-5p aberrant expression can influence many malignancy-related processes such as cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition, as well as angiogenesis and responsiveness to treatment. In many cancer types (such as lung, prostate, gastric, breast, bladder, ovarian, colorectal, and pancreatic cancer, and osteosarcoma), miR-330-5p acts as an anti-tumor agent. These cancers have low levels of miR-330-5p that leads to the upregulation of the tumor promotor target genes leading to tumor progression. Here, overexpression of miR-330-5p using miRNA inducers can prevent tumor development. Dual roles of miR-330-5p have been also indicated in the thyroid, liver and cervical cancers. Moreover, miR-330-3p exhibits pro-tumorigenesis effects in lung cancer, pancreatic cancer, osteosarcoma, bladder cancer, and cervical cancer. Here, downregulation of miR-330-3p using miRNA inhibitors can prevent tumor development. Demonstrated in breast and liver cancers, miR-330-3p also has dual roles. Importantly, the activities of miR-330-3p and/or miR-330-5p are regulated by upstream regulators long non-coding RNAs (lncRNAs), including circular and linear lncRNAs. This review comprehensively explained miR-330-3p and miR-330-5p role in development of cancers, while highlighting their downstream target genes and upstream regulators as well as possible therapeutic strategies.

CircLRP6 contributes to prostate cancer growth and metastasis by binding to miR-330-5p to up-regulate NRBP1

Background

Circular RNA low-density lipoprotein receptor-related protein 6 (circLRP6) is considered as an oncogene in many types of cancers. However, the function and mechanisms of circLRP6 in prostate cancer (PCa) tumorigenesis remain largely undefined.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays were conducted to assess the expression of circLRP6, microRNA (miR)-330-5p, and nuclear receptor binding protein 1 (NRBP1). Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2’-deoxyuridine (EDU) incorporation, flow cytometry, transwell, wound healing, and western blot assays were performed to detect cell proliferation, apoptosis, and metastasis in vitro. Subcutaneous tumor growth was observed in nude mice to investigate the role of circLRP6 in vivo. The targeting relationship between miR-330-5p and NRBP1 or circLRP6 was verified using dual-luciferase reporter, pull-down, and RNA immunoprecipitation (RIP) assays. Immunohistochemistry was employed to test relative protein expression.

Results

CircLRP6 was highly expressed in PCa tissues and cells, knockdown of circLRP6 impaired PCa cell growth and metastasis in vitro by affecting cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT). Mechanistic studies showed that circLRP6 could competitively bind with miR-330-5p to prevent the degradation of its target gene NRBP1. Rescue assay suggested that miR-330-5p inhibition reversed the inhibitory effects of circLRP6 knockdown on PCa cell growth and metastasis. Moreover, overexpression of miR-330-5p suppressed PCa progression via NRBP1. Notably, tumor formation assay indicated that circLRP6 silencing impeded tumor growth and EMT in vivo.

Conclusion

Our findings demonstrated that circLRP6 promoted PCa tumorigenesis and metastasis through miR-330-5p/NRBP1 axis, suggesting a potential therapeutic target for PCa.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02287-2.

LINC00311 promotes cancer stem-like properties by targeting miR-330-5p/TLR4 pathway in human papillary thyroid cancer

Growing evidence has suggested that long noncoding RNAs (lncRNAs) play an essential role in the progression of papillary thyroid cancer (PTC). LncRNA LINC00311 was found to be able to regulate many cellular process in several diseases. However, the function and regulatory mechanism of LINC00311 remains unclear in PTC. In the present study, the results showed that the expression of LINC00311 was upregulated in PTC tissues and cells. Furthermore, knockdown of LINC00311 dramatically suppressed spheroid formation, proliferation, migration, and invasion in PTC cells in vitro. Mechanistic investigations revealed that LINC00311 was negatively correlated with the expression of miR‐330‐5p, meanwhile, TLR4 was a direct target of miR‐330‐5p. In addition, rescue assays further determined that LINC00311 contributed to the progression of PTC through regulating TLR4 expression. Taken together, these findings indicated that LINC00311 could promote cancer stem‐like properties by targeting miR‐330‐5p/TLR4 pathway in PTC.

lncRNA PCAT6 promotes non-small cell lung cancer cell proliferation, migration and invasion through regulating miR-330-5p

Background

Investigating the roles of lncRNA prostate cancer-associated transcript 6 (PCAT6) in modulating the growth and aggressiveness of non-small-cell lung carcinoma (NSCLC) cell.

Method

The levels of PCAT6 in NSCLC tissues and cell lines were determined by quantitative real-time PCR assay. MTT as well as colony formation assays were applied to explore the effect of PCAT6 on the growth of NSCLC cell in vitro. Wound healing and Transwell assays were utilized to analyze the impact of PCAT6 on the migration and invasion of NSCLC cell. Bioinformatics analysis and luciferase reporter assay were used to prove that miR-330-5p was the target of PCAT6. Colony formation, wound healing, and Transwell invasion assays were applied to demonstrate that PCAT6 promoted NSCLC cell growth, migration, and invasion through binding miR-330-5p. Finally, xenograft model was used to explore the role of PCAT6 in the tumor growth of NSCLC cell in vivo.

Results

PCAT6 was highly overexpressed in NSCLC tissues and cells compared with normal tissues and non-tumorigenic bronchial epithelial cell line, BEAS-2B. Downregulation of PCAT6 markedly reduced the proliferation, migration, and invasion of NSCLC cell. Moreover, down-expression of PCAT6 significantly increased the level of miR-330-5p in NSCLC cell. Further functional experiments indicated that down-expression of miR-330-5p reversed the inhibitory effect of PCAT6 on NSCLC cell growth, migration, and invasion.

Conclusion

Our results reveal that lncRNA PCAT6 facilitates the proliferation, migration, and invasion of NSCLC cell via competitively binding to miR-330-5p.