Long Non-Coding RNA ASB16-AS1 Functions as a miR-760 Sponge to Facilitate the Malignant Phenotype of Osteosarcoma by Increasing HDGF Expression

Purpose

ASB16 antisense RNA 1 (ASB16-AS1) is a cancer-associated long non-coding RNA that contributes to tumorigenesis and tumor development. Nevertheless, to the best of our knowledge, whether and how ASB16-AS1 is implicated in osteosarcoma (OS) malignancy remains unclear and therefore warrants exploration. Our current study focused on making in-depth investigation of ASB16-AS1 in OS. In the present study, the expression pattern of ASB16-AS1 in OS tissues and cell lines was analyzed. In addition, we examined the clinical value of ASB16-AS1 for OS patients. Furthermore, we explored the impacts of ASB16-AS1 on the malignant phenotype of OS cells in vitro and in vivo as well as the underlying mechanism.

Methods

ASB16-AS1, microRNA-760 (miR-760) and hepatoma-derived growth factor (HDGF) expressions were measured using reverse transcription-quantitative PCR. Cell proliferation and apoptosis were evaluated using CCK-8 and flow cytometry analyses, respectively, and cell migration and invasion were determined via cell migration and invasion assays.

Results

ASB16-AS1 expression was significantly elevated in OS tissues and cell lines, and increased ASB16-AS1 expression was related to patients' tumor size, TNM stage, and distant metastasis. The overall survival rate of OS patients presenting high ASB16-AS1 expression was shorter than that of patients presenting low ASB16-AS1 expression. Reduced ASB16-AS1 expression inhibited OS cell proliferation, migration, and invasion; promoted cell apoptosis; and impaired tumor growth in vivo. Mechanistically, ASB16-AS1 served as a sponge for miR-760 and positively modulated the expression of its target HDGF. Finally, inhibiting miR-760 and restoring HDGF expression abolished the impacts of ASB16-AS1 knockdown on the malignant characteristics of OS cells.

Conclusion

ASB16-AS1 is a novel oncogenic lncRNA in OS cells. ASB16-AS1 increased HDGF expression by sponging miR-760, thereby conferring cancer-promoting roles in OS. ASB16-AS1 is a potential early diagnostic and therapeutic target in OS.

Long Noncoding RNA FOXD2-AS1 Promotes the Malignancy of Cervical Cancer by Sponging MicroRNA-760 and Upregulating Hepatoma-Derived Growth Factor

Although the functions of long noncoding RNA (lncRNA) called FOXD2 adjacent opposite strand RNA 1 (FOXD2-AS1) have been well studied in multiple human cancer types, its expression status and detailed roles in cervical cancer remain unknown and merit investigation. This study was aimed at assessing FOXD2-AS1 expression in cervical cancer and at determining its effects on the aggressive behavior of cervical cancer in vitro and in vivo. Expression of FOXD2-AS1 in cervical cancer tissues and cell lines was determined via reverse-transcription quantitative PCR. The effects of FOXD2-AS1 on cervical cancer cells were examined by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, flow-cytometric analysis, migration and invasion assays, and an in vivo tumorigenicity assay. FOXD2-AS1 was found to be significantly upregulated in cervical cancer tissues and cell lines. High FOXD2-AS1 expression was notably linked with the Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and depth of cervical invasion in patients with cervical cancer. Kaplan-Meier survival analysis revealed significantly shorter overall survival of patients when the tumor expression of FOXD2-AS1 was higher in comparison with those in patients with lower FOXD2-AS1 expression. In vitro functional assays revealed that downregulation of FOXD2-AS1 led to suppression of proliferation, migration, and invasiveness as well as to the induction of apoptosis of cervical cancer cells. In addition, FOXD2-AS1 silencing hindered tumor growth in vivo. Mechanism investigation revealed that FOXD2-AS1 functioned as a molecular sponge of microRNA-760 (miR-760). Furthermore, hepatoma-derived growth factor (HDGF) was validated as a direct target gene of miR-760 in cervical cancer cells. Moreover, an miR-760 knockdown reversed the effects of FOXD2-AS1 silencing on cervical cancer cells. FOXD2-AS1 possesses significant oncogenic activity in cervical cancer progression; this activity is mediated by sponging of miR-760 with consequent upregulation of HDGF. The FOXD2-AS1-miR-760-HDGF axis might harbor promising targets for novel treatment strategies of cervical cancer.

Prognostic role of miR-760 in hepatocellular carcinoma

Previous studies have demonstrated that microRNA (miR)-760 serves an important role in various cancer types. However, to the best of our knowledge, its role in hepatocellular carcinoma (HCC) has not been fully elucidated. The current study investigated the prognostic role of miR-760 in HCC by using the Kaplan-Meier plotter database. The current data indicated that low expression of miR-760 was associated with higher overall survival (OS) for all patients with HCC from both the RNA-seq [hazard ratio (HR)=2.04; 95% confidence interval (CI)=1.44–2.89; P=4.9×10⁻⁵] and the non-commercial spotted microarray (HR=1.71; CI=1.05–2.76; P=0.028). In the RNA-seq platform, a lower expression of miR-760 was strongly associated with improved OS in male patients with HCC, but not in female patients with HCC. Additionally, low expression of miR-760 was associated with improved OS in patients with stage I, II and III HCC, and was associated with improved OS in Asian and Caucasian patients. The current results indicated that miR-760 serves as an oncogene for HCC and high expression of miR-760 is significantly associated with tumor progression and poor prognosis in patients with HCC.