Long Noncoding RNA CCDC144NL-AS1 Promotes the Oncogenicity of Osteosarcoma by Acting as a Molecular Sponge for microRNA-490-3p and Thereby Increasing HMGA2 Expression
Authors: Shian Liao
Hao Mo
Juliang He
Zhenjie Wu
Bin Liu
Zhenchao Yuan
Jian Guan
Journal: OncoTargets and Therapy (2021)
Discipline: CLINICAL MEDICINE
Keywords: competitive endogenous RNA; high-mobility group AT-hook 2; long noncoding RNA; microRNA.
Affiliations: Department of Bone and Soft Tissue Surgery, Guangxi Medical University Cancer Hospital, Nanning, Guangxi 530021, People's Republic of China.

Abstract:  Purpose: The long noncoding RNA CCDC144NL antisense RNA 1 (CCDC144NL-AS1) exhibits important functions in gastric cancer. In this study, we aimed to investigate the roles of CCDC144NL-AS1 in modulating the phenotype of osteosarcoma (OS) cells in vitro and in vivo and elucidate its underlying mechanisms. Methods: Reverse transcription quantitative polymerase chain reaction (PCR) was performed to determine the expression level of CCDC144NL-AS1 in OS tissues and cell lines. The proliferation, apoptosis, migration, and invasion in vitro as well as tumor growth in vivo were determined in OS cells using the Cell Counting Kit 8 assay, flow cytometric analysis, transwell migration and invasion assays, and xenograft experiments, respectively. Bioinformatics analysis was performed to identify the potential microRNA targets of CCDC144NL-AS1, which were subsequently confirmed using the luciferase reporter assay, RNA immunoprecipitation assay, reverse transcription quantitative PCR, Western blotting, and rescue experiments. Results: CCDC144NL-AS1 expression was upregulated in OS tissues and cell lines. Patients with OS who exhibited high CCDC144NL-AS1 expression had shorter overall survival than those who exhibited low CCDC144NL-AS1 expression. Functionally, interference in CCDC144NL-AS1 expression led to a notable decrease in the proliferation, migration, and invasion of OS cells and an increase in cell apoptosis in vitro. Furthermore, CCDC144NL-AS1 knockdown impaired OS tumor growth in vivo. Mechanistically, CCDC144NL-AS1 directly bound to miR-490-3p in OS cells, where it functioned as a molecular sponge and subsequently increased the expression of high-mobility group AT-hook 2 (HMGA2). Rescue experiments further demonstrated that miR-490-3p suppression or HMGA2 restoration abated CCDC144NL-AS1 deficiency-induced cancer-inhibitory actions in OS cells. Conclusion: CCDC144NL-AS1 exhibits pro-oncogenic roles in OS by functioning as a sponge for miR-490-3p and increasing HMGA2 expression. Our findings suggest that greater understanding of the CCDC144NL-AS1/miR-490-3p/HMGA2 pathway can provide useful information for OS diagnosis, prognosis, and therapy. 

Retracted: No

PubPeer comments:
 Here are multiple appearances of what seems to be the same well-traveled ruler, marked by a distinctive scratch just to the right of 2 . Different teams of researchers from six different institutions somehow used it to provide scale for the xenograft tumors in their studies. There would be no problem if all the images had been recorded at a single lab, but the papers do not mention outsourcing any of the experiments to an outside contractor. Upper row: - Fig 7B from [Chen et al (2021)] .  Representative images of subcutaneous tumours collected from the sh-USP30-AS1 and sh-NC groups. Rotated through 90 deg for ease of comparison. - Fig 8A from [Luo et al (2020)] .  Representative images of tumor xenografts originating from SW480 cells stably expressing sh-LINC00239 or sh-NC. Rotated through 90 deg. - Fig 7A from [Liu et al (2020)] .  Representative images of tumor xenografts that originated from SW480 cells stably overexpressing sh-VPS9D1-AS1 or sh-NC . ![file] Middle row: - **Fig 7B from [He et al (2021)] **.  At 31 days following cell injection, all mice were euthanized and tumor xenografts were resected and imaged . - Fig 6B from [Liu et al (2020)] .  All mice were euthanized at the end of the experiment, and the tumor xenografts were harvested and imaged . Rotated through 90 deg. - Fig 8A from [Yang, Yang Wang (2020)] .  Tumor growth curves were plotted according to the tumor volumes measured weekly . ![file] Lower row: - Fig 7B from [Li et al (2020)] .  Representative images of tumor xenografts collected from short hairpin RNA (sh)-LINC00525 and control (sh-NC) groups . - Fig 6A from [Dai et al (2020)] .  After 28 days post-inoculation, mice were euthanized and tumor xenografts were dissected and photographed . ![file] , 
 Expression of Concern, [15 October 2021] . ----------------------------------- The Editor and Publisher of *OncoTargets and Therapy* wish to publish an Expression of Concern for the published article. Following publication, concerns were raised about the scientific integrity of the articles content. We reached out to the authors requesting they supply information that would confirm the integrity of the data. The authors provided several files in response to our queries but they did not satisfy our requirements to confirm the authenticity of some types of data. In addition, there were unexplained similarities between some of the figures presented in this article, and figures presented in articles by different authors groups. As yet, the authors have not provided a satisfactory explanation for this. Therefore, as we continue to work through the issues raised, we advise readers to interpret the information presented in the article with due caution. The authors have been notified about this Expression of Concern. ,