Upregulation of lncRNA ADAMTS9-AS2 Promotes Salivary Adenoid Cystic Carcinoma Metastasis via PI3K/Akt and MEK/Erk Signaling

Long noncoding RNA ADAMTS9-AS2 suppresses the progression of esophageal cancer by mediating CDH3 promoter methylation

Long noncoding RNAs (lncRNAs) have been implicated in the biology of esophageal cancer via mRNA degradation or translational inhibition. CDH3 is also aberrantly expressed in numerous cancers. This study was conducted with the hypothesis that ADAMTS9-AS2 or CDH3 methylation plays a role in esophageal cancer cell activity and in vivo development. Firstly, mRNA levels of ADAMTS9-AS2 and CDH3 in esophageal cancer tissues and cells were detected by reverse-transcription quantitative polymerase chain reaction. Afterward, esophageal cancer OE21 cells were treated with overexpression of ADAMTS9-AS2, siRNA against ADAMTS9-AS2, overexpression of CDH3 and demethylating agent 5-aza-dc. The biological functions of esophageal cancer OE21 cells were assayed to define the regulatory mechanisms of ADAMTS9-AS2 in esophageal cancer. The interactions among ADAMTS9-AS2, DNMT1/DNMT3 (A/B) and CDH3 were detected by MSP, RNA pull-down, RIP, and ChIP assays. The in vitro findings were reproduced in nude mice to explore the role of ADAMTS9-AS2 in the development of esophageal cancer in vivo. Esophageal cancers expressed low levels of ADAMTS9-AS2 and high levels of CDH3. Methylation of CDH3 promoter was induced by ADAMTS9-AS2 via DNMT1/DNMT3 (A/B). Furthermore, proliferation, invasion, and migration of esophageal cancer cells were inhibited by ADAMTS9-AS2 via downregulation of CDH3. Suppressed esophageal cancer development in vivo was also detected after ADAMTS9-AS2 overexpression. Overexpressed ADAMTS9-AS2 aids in the suppression of esophageal cancer development, which is achieved via inducing CDH3 promoter methylation.

Novel Function of lncRNA ADAMTS9-AS2 in Promoting Temozolomide Resistance in Glioblastoma via Upregulating the FUS/MDM2 Ubiquitination Axis

Background

LncRNAs have been shown to play essential roles in cancer therapeutic response. However, the detailed mechanism of lncRNAs in temozolomide (TMZ) resistance in glioblastoma (GBM) remain to be elucidated.

Methods

To elucidate the mechanism maintaining TMZ resistance, we constructed two TMZ-resistant GBM cell lines (T98G-R/U118-R). LncRNAs from four public datasets were reanalyzed, and the candidate lncRNA ADAMTS9-AS2 was evaluated in TMZ-treated GBM patients and in vitro cell lines.

Results

Reanalysis of lncRNA expression profiles identified ADAMTS9-AS2 as significantly overexpressed in TMZ-resistant GBM cells and as positively associated with the IC₅₀ of TMZ in GBM cells. Overexpression of ADAMTS9-AS2 was also significantly associated with poor TMZ response and shorter progression-free survival (PFS) in TMZ-treated GBM patients. Knockdown of ADAMTS9-AS2 inhibited proliferation and attenuated the IC₅₀ of TMZ, as well as mitigating invasion and migration in TMZ-resistant GBM cells. Subsequent investigations indicated that reduced expression of ADAMTS9-AS2 significantly suppressed expression of the FUS protein, which was predicted as a direct substrate of ADAMTS9-AS2. Expression trends of FUS were directly correlated with those of ADAMTS9-AS2, as shown by increasing concentrations and prolonged treatment with TMZ. RNA pull-down and RIP assays indicated that both endogenous and exogenous ADAMTS9-AS2 directly binds to the RRM and Znf_RanBP2 domains of FUS, consequently increasing FUS protein expression. Knockdown of ADAMTS9-AS2 reduced the half-life of FUS and decreased FUS protein stability via K48 ubiquitin degradation. Moreover, the E3 ubiquitin-protein ligase MDM2 interacts with and down regulates FUS, while the RRM and Znf_RanBP2 domains of FUS facilitate its binding with MDM2. ADAMTS9-AS2 decreased the interaction between MDM2 and FUS, which mediates FUS K48 ubiquitination. Additionally, knockdown of the ADAMTS9-AS2/FUS signaling axis significantly alleviated progression and metastasis in TMZ-resistant cells.

Conclusion

ADAMTS9-AS2 possessed a novel function that promotes TMZ resistance via upregulating the FUS/MDM2 axis in GBM cells. The RRM or Znf_RanBP2 domains of FUS facilitate the combination of ADAMTS9-AS2 and FUS, competitively inhibiting MDM2-dependent FUS K48 ubiquitination and resulting in enhanced FUS stability and TMZ resistance. Our results suggest that the ADAMTS9-AS2/FUS/MDM2 axis may represent a suitable prognostic biomarker and a potential target in TMZ-resistant GBM therapy.

LncRNA FOXD2-AS1 accelerates the papillary thyroid cancer progression through regulating the miR-485-5p/KLK7 axis

It has been proved that long noncoding RNAs (lncRNAs) are important modulators in the tumorigenesis and progression of various malignant tumors. Recently, lncRNA FOXD2-AS1 has been reported to be an oncogene in several kinds of human cancers. However, the function of FOXD2-AS1 in papillary thyroid cancer (PTC) has not been well investigated. This study aims to explore the biological role and mechanism of FOXD2-AS1 in PTC. At first, the expression of FOXD2-AS1 was examined in PTC tissues and cell lines with quantitative reverse transcription-polymerase chain reaction (qRT-PCR). FOXD2-AS1 was found to observably upregulated in PTC tissues and cell lines. Kaplan-Meier survival analysis revealed that high expression of FOXD2-AS1 was closely correlated with the unfavorable prognosis of patients with PTC. Based on the TCGA data set, KLK7 was overexpressed in PTC tumor samples. Our experimental data further validated the upregulation of KLK7 in PTC tissues and cell lines. Similarly, high level of KLKF was associated with poor prognosis of patients with PTC. The positive expression association between FOXD2-AS1 and KLK7 was analyzed with Pearson correlation coefficient. Loss-of-function assays revealed that knockdown of FOXD2-AS1 or KLK7 greatly inhibited PTC cell proliferation and migration, while induced cell apoptosis. Results of mechanism experiments suggested that FOXD2-AS1 functioned as a competing endogenous RNA (ceRNA) to enhance the expression of KLK7 by sponging miR-485-5p in PTC. Rescue assays were conducted to verify the function of FOXD2-AS1/miR-485-5p/KLK7 axis in PTC progression.

LncRNA ADAMTS9-AS2 promotes tongue squamous cell carcinoma proliferation, migration and EMT via the miR-600/EZH2 axis

Long noncoding RNAs (lncRNAs) are a type of noncoding RNA transcript that are characterized by lack of protein-coding capacity. The vital role of lncRNAs in tongue squamous cell carcinoma (TSCC) is attracting increasing attention. In the present study, we identify a key lncRNA regulating TSCC metastasis and investigated the underlying mechanism. Our results indicate that the lncRNA ADAMTS9-AS2 is most significantly upregulated in TSCC tissues from patients with lymph node metastasis and is closely associated with poor prognosis. Furthermore, ADAMTS9-AS2 knockdown in TSCC cells leads to a inhibition of cell migration and invasion and reverses TGF-β1 induced EMT. ADAMTS9-AS2 knockdown also inhibits TSCC cell growth in vitro and in vivo. In addition, we show that ADAMTS9-AS2 is a cytoplasmic lncRNA that shares the miRNA response elements (MREs) of miR-600 with EZH2, which is confirmed by a luciferase reporter assay and AGO2-dependent RNA immunoprecipitation (RIP). In summary, our results demonstrate an explicit oncogenic role of ADAMTS9-AS2 in TSCC tumorigenesis via competition with miR-600, suggesting a new regulatory mechanism of ADAMTS9-AS2 and providing a potential therapeutic target for TSCC patients.

DANCR Promotes Metastasis and Proliferation in Bladder Cancer Cells by Enhancing IL-11-STAT3 Signaling and CCND1 Expression

The prognosis for patients with bladder cancer (BCa) with lymph node (LN) metastasis is poor, and it is not improved by current treatments. Long noncoding RNAs (lncRNAs) are involved in the pathology of various tumors, including BCa. However, the role of Differentiation antagonizing non-protein coding RNA (DANCR) in BCa LN metastasis remains unclear. In this study, we discover that DANCR was significantly upregulated in BCa tissues and cases with LN metastasis. DANCR expression was positively correlated with LN metastasis status, tumor stage, histological grade, and poor patient prognosis. Functional assays demonstrated that DANCR promoted BCa cell migration, invasion, and proliferation in vitro and enhanced tumor LN metastasis and growth in vivo. Mechanistic investigations revealed that DANCR activated IL-11-STAT3 signaling and increased cyclin D1 and PLAU expression via guiding leucine-rich pentatricopeptide repeat containing (LRPPRC) to stabilize mRNA. Moreover, oncogenesis facilitated by DANCR was attenuated by anti-IL-11 antibody or a STAT3 inhibitor (BP-1-102). In conclusion, our findings indicate that DANCR induces BCa LN metastasis and proliferation via an LRPPRC-mediated mRNA stabilization mechanism. DANCR may serve as a multi-potency target for clinical intervention in LN-metastatic BCa.