lncRNA HOXA11-AS maintains the stemness of oral squamous cell carcinoma stem cells and reduces the radiosensitivity by targeting miR-518a-3p/PDK1

OBJECTIVE

Oral squamous cell carcinoma (OSCC) is the most prevailing oral malignancy. The lncRNA HOXA11-AS shows prominent roles in OSCC. This study explored the effects of lncRNA HOXA11-AS on regulating OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p/PDK1.

METHODS

Human OSCC cell lines SCC9 and SCC15 were selected. CD133⁺ cancer stem cells (CSCs) were sorted by immunomagnetic beads. CD133 expression in cells and HOXA11-AS expression in SCC9, SCC15, and CD133⁺ SCC9, CD133⁺ SCC15 cells were assessed by flow cytometry and RT-qPCR. HOXA11-AS was silenced/overexpressed in SCC9, SCC15, CD133⁺ SCC9, and CD133⁺ SCC15 cells. Cell proliferation, radiosensitivity, invasion, and stem cell sphere formation ability were examined by CCK-8, colony formation, Transwell, and stem cell sphere formation. The levels of stemness-related genes (Oct4, Nanog, Sox2), miR-518a-3p, epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, Vimentin, N-cadherin), and PDK1 were assessed by RT-qPCR and Western blot assay.

RESULTS

HOXA11-AS was up-regulated in SCC9, SCC15, CD133⁺ SCC9, and CD133⁺ SCC15 cells. HOXA11-AS silencing inhibited OSCC proliferation and invasion and enhanced radiosensitivity. HOXA11-AS maintained CSC stemness in OSCC. HOXA11-AS silencing reduced CD133⁺ SCC9 and CD133⁺ SCC15 stem cell sphere formation ability, reduced stem cell stemness-related gene levels, and inhibited EMT. HOXA11-AS regulated OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p. PDK1 overexpression annulled the regulatory effects of HOXA11-AS silencing on OSCC cell stem cell stemness and radiosensitivity.

CONCLUSION

In vitro lncRNA HOXA11-AS silencing inhibited OSCC stem cell stemness by targeting the miR-518a-3p/PDK1 axis, thus enhancing OSCC cell radiosensitivity.

Exosomal circNFIX promotes angiogenesis in ovarian cancer via miR-518a-3p/TRIM44 axis

Ovarian cancer (OC) is a gynecological cancer with high mortality. OC-derived exosomal circRNAs can regulate angiogenesis. This study aims to explore the role and mechanism of exosomal circRNA nuclear factor I X (CircNFIX) derived from OC cells in angiogenesis. Quantitative real-time polymerase chain reaction was employed to evaluate the levels of circNFIX, miR-518a-3p, and tripartite motif protein 44 (TRIM44) in OC and adjacent tissues. Exosomes from the ovarian surface epithelial cell (HOSEpiC) and OC cells (SKOV3 or OVCAR3) were isolated by differential centrifugation. Exosomes were cocultured with the human umbilical vein endothelial cells (HUVECs). The angiogenesis capacity was analyzed by Tube formation assay. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and Transwell assays were used to determine the cell viability and migration ability. The dual-luciferase report, RNA immunoprecipitation (RIP), and RNA pull-down assays were applied to validate the gene's interaction. CircNFIX and TRIM44 expression were higher and miR-518a-3p was lower in OC tissues than in the adjacent tissues. Upregulated circNFIX and TRIM44 were significantly correlated with the tumor size and International Federation of Gynecology and Obstetrics (FIGO) stage of OC patients. HUVECs treated OC-derived exosomes had higher proliferation, migration, and angiogenesis capacities than the control group. While OC-derived exosomal circNFIX silencing restrained HUVECs' proliferation, migration, and angiogenesis, compared with the OC-derived exosomes group. OC-derived exosomal circNFIX positively regulated TRIM44 expression by targeting miR-518a-3p in HUVECs. OC-derived exosomal circNFIX promoted angiogenesis by regulating the Janus-activated kinase/signal transducer and activator of transcription 1 (JAK/STAT1) pathway via miR-518a-3p/TRIM44 axis in HUVECs.

miR-518a-3p Suppresses Triple-Negative Breast Cancer Invasion and Migration Through Regulation of TMEM2

MicroRNAs (miRNAs) are emerging as critical mediators in tumors, including triple-negative breast cancer (TNBC). The role of miR-518a-3p in TNBC was investigated to identify potential therapeutic target. Data from KM Plotter database (www.kmplot.com) showed that high miR-518a-3p expression was significantly associated with overall survival of patients with TNBC (p = 0.04). The expression of miR-518a-3p was dysregulated in TNBC cells. Functional assays revealed that over-expression of miR-518a-3p inhibited cell invasion and migration of TNBC. Additionally, miR-518a-3p could target TMEM2 (transmembrane protein 2), and decreased protein and mRNA expression of TMEM2 in TNBC cells. Knockdown of TMEM2 suppressed cell invasion and migration through inhibiting phospho (p)-JAK1 (Janus kinase 1) and p-STAT (signal transducer and activator of transcription protein) 1/2. Moreover, over-expression of TMEM2 counteracted the suppressive effect of miR-518a-3p on TNBC invasion and migration through promoting the levels of p-JAK1 and p-STAT1/2. In conclusion, miR-518a-3p negatively regulates the JAK/STAT pathway via targeting TMEM2 and suppresses invasion and migration in TNBC, suggesting that miR-518a-3p may be a potential therapeutic target in TNBC.

HOXA11-AS promotes the progression of oral squamous cell carcinoma by targeting the miR-518a-3p/PDK1 axis

Background

Long non-coding RNAs (lncRNAs) are promising therapeutic molecules of cancer. Here we aim to study the therapeutic effect and mechanism of a lncRNA, HOXA11-AS, in oral squamous cell carcinoma (OSCC).

Methods

OSCC tissues and adjacent matched paraneoplastic normal tissues used in this study were collected from 42 OSCC patients. The significant downregulation or upregulation of HOXA11-AS expression in OSCC cells was confirmed by quantitative real-time PCR (qRT-PCR). Bioinformatics analysis of StarBase were performed to investigate the potential microRNAs mediated by HOXA11-AS. HOXA11-AS-transfected cells or control cells were subcutaneously injected into nude mice to further determine the effects of HOXA11-AS on OSCC progression in vivo.

Results

qRT-PCR analysis indicated that HOXA11-AS expression was significantly upregulated in OSCC tissues. Functional studies revealed that HOXA11-AS significantly promotes cell proliferation, reduces the percentage of G0/G1 phase cells and enhances the cell invasion in OSCC. Bioinformatics analysis suggested that a microRNA (miRNA), miR-518a-3p, is as a target of HOXA11-AS. Alteration of miR-518a-3p levels by HOXA11-AS transduced to changes in PDK1 expression. In a mouse model of OSCC, HOXA11-AS overexpression promoted tumor growth, concomitant with reduced miR-518a-3p expression and increased PDK1 expression.

Conclusion

Taken together, our study demonstrates that HOXA11-AS/miR-518a-3p/PDK1 axis is an important regulator of OSCC progression and may serve as a potential therapeutic target in OSCC. HARMU20150128, registered at Jan, 28 2018.