TMPO-AS1 promotes cell proliferation of thyroid cancer via sponging miR-498 to modulate TMPO

Long noncoding RNA TMPO-AS1 upregulates BCAT1 expression to promote cell proliferation in nasopharyngeal carcinoma via microRNA let-7c-5p

BACKGROUND

Long non-coding RNA (lncRNA) is a group of RNA transcripts that contribute to tumor development by post-transcriptionally regulating cancer-related genes. Nasopharyngeal carcinoma (NPC) is an epithelial tumor that occurs in the nasopharynx and is common in North Africa and Southeast Asia. The study investigated the functions of lncRNA TMPO-AS1 in NPC cell proliferation and apoptosis as well as its related competing endogenous RNA (ceRNA) mechanism.

METHODS

Candidate microRNA and genes that may regulated by TMPO-AS1 were predicted with the bioinformatic tool starBase. TMPO-AS1 expression in NPC tissue, cells, nuclear part, and cytoplasmic part was measured by RT-qPCR. MTT assay, EdU assay, and flow cytometry analysis were carried out to evaluate NPC cell viability, proliferation, and apoptosis, respectively. RNA immunoprecipitation assay and luciferase reporter assay were conducted to detect the binding between TMPO-AS1 and let-7c-5p or that between let-7c-5p and BCAT1.

RESULTS

TMPO-AS1 and BCAT1 showed high expression in NPC tissue and cells, while let-7c-5p was downregulated in NPC. The silencing of TMPO-AS1 suppressed NPC cell proliferation while promoting cell apoptosis. Moreover, TMPO-AS1 interacted with let-7c-5p and negatively regulated let-7c-5p expression. BCAT1 was a target of let-7c-5p and was inversely regulated by let-7c-5p in NPC cells. The repressive impact of TMPO-AS1 knockdown on NPC cell growth was countervailed by overexpressed BCAT1.

CONCLUSION

TMPO-AS1 accelerates NPC cell proliferation and represses cell apoptosis by interacting with let-7c-5p to regulate BCAT1 expression.

Hsa_circ_0079480 enhances cell proliferation, migration, and invasion in colorectal cancer through miR-498/ATP5E axis

Circular RNAs play critical roles in tumorigenesis. hsa_circ_0079480 was reported to be upregulated in colorectal cancer (CRC). However, its specific molecule in CRC is poorly understood. Hsa_circ_0079480, miR-498, and ATP5E expressions in CRC tissues and CRC cells were determined using quantitative real-time polymerase chain reaction assay. ATP5E protein level was assessed using Western blot. Cell proliferation, migration, and invasion were examined by 3-(4, 5-Dimethylthiazolyl2)-2, 5-diphenyltetrazolium bromide assay and Transwell assays, respectively. Dual-luciferase reporter gene assay was performed to analyze the interactions between hsa_circ_0079480, miR-498, and ATP5E. This study results showed that hsa_circ_0079480 and ATP5E expressions were significantly increased in CRC tissues and CRC cells, while miR-498 was downregulated. Hsa_circ_0079480 knockdown dramatically suppressed CRC cell proliferation, migration, and invasion. Meanwhile, it turned out that hsa_circ_0079480 knockdown inhibited CRC tumor growth in vivo. Hsa_circ_0079480 could negatively regulate miR-498 expression by directly targeting miR-498. MiR-498 overexpression dramatically inhibited CRC cell malignant behaviors. miR-498 negatively regulated ATP5E expression by directly binding to ATP5E. ATP5E knockdown suppressed CRC cell malignant behaviors. ATP5E overexpression mitigated the inhibitory effect of hsa_circ_0079480 on CRC cell malignant behaviors. Since hsa_circ_0079480 knockdown inhibited CRC cells malignant behaviors through regulation of the miR-498/ATP5E axis, it can be concluded that hsa_circ_0079480 might have great potential as therapeutic target for CRC.

A long non-coding RNA with important roles in the carcinogenesis

Long non-coding RNAs are demonstrated to contribute to carcinogenesis. TMPO Antisense RNA 1 (TMPO-AS1) is an example of lncRNAs with crucial roles in this process. This lncRNA serves as a sponge for miR-320a, miR-383-5p, miR-329-3p, miR-126, miR-329, miR-199a-5p, miR-577, miR-4731-5p, miR-140-5p, miR-1179, miR-143-3p, miR-326, miR-383-5p, let-7c-5p, let-7g-5p, miR-199a-5p, miR-200c, miR-204-3p, miR-126-5p, miR-383-5p, miR-498, miR-143-3p, miR-98-5p, miR-140 and miR-143. It can also affect activity of PI3K/Akt/mTOR pathway. The current review summarizes the role of TMPO-AS1 in the carcinogenesis and assessment of its potential as a marker for certain types of cancers.

ADAR1-Mediated RNA Editing and Its Role in Cancer

It is well known that the stability of RNA, the interaction between RNA and protein, and the correct translation of protein are significant forces that drive the transition from normal cell to malignant tumor. Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA editing enzyme that catalyzes the deamination of adenosine to inosine (A-to-I), which is one dynamic modification that in a combinatorial manner can give rise to a very diverse transcriptome. ADAR1-mediated RNA editing is essential for survival in mammals and its dysregulation results in aberrant editing of its substrates that may affect the phenotypic changes in cancer. This overediting phenomenon occurs in many cancers, such as liver, lung, breast, and esophageal cancers, and promotes tumor progression in most cases. In addition to its editing role, ADAR1 can also play an editing-independent role, although current research on this mechanism is relatively shallowly explored in tumors. In this review, we summarize the nature of ADAR1, mechanisms of ADAR1 editing-dependent and editing-independent and implications for tumorigenesis and prognosis, and pay special attention to effects of ADAR1 on cancers by regulating non-coding RNA formation and function.

LncRNA TMPO-AS1 promotes esophageal squamous cell carcinoma progression by forming biomolecular condensates with FUS and p300 to regulate TMPO transcription

Esophageal squamous cell carcinoma (ESCC) is one of the most life- and health-threatening malignant diseases worldwide, especially in China. Long noncoding RNAs (lncRNAs) have emerged as important regulators of tumorigenesis and tumor progression. However, the roles and mechanisms of lncRNAs in ESCC require further exploration. Here, in combination with a small interfering RNA (siRNA) library targeting specific lncRNAs, we performed MTS and Transwell assays to screen functional lncRNAs that were overexpressed in ESCC. TMPO-AS1 expression was significantly upregulated in ESCC tumor samples, with higher TMPO-AS1 expression positively correlated with shorter overall survival times. In vitro and in vivo functional experiments revealed that TMPO-AS1 promotes the proliferation and metastasis of ESCC cells. Mechanistically, TMPO-AS1 bound to fused in sarcoma (FUS) and recruited p300 to the TMPO promoter, forming biomolecular condensates in situ to activate TMPO transcription in cis by increasing the acetylation of histone H3 lysine 27 (H3K27ac). Targeting TMPO-AS1 led to impaired ESCC tumor growth in a patient-derived xenograft (PDX) model. We found that TMPO-AS1 is required for cell proliferation and metastasis in ESCC by promoting the expression of TMPO, and both TMPO-AS1 and TMPO might be potential biomarkers and therapeutic targets in ESCC.

The role of a regulatory RNA in promoting esophageal squamous cell carcinoma (ESCC) has been clarified, revealing molecular details that might help in cancer diagnosis and treatment. Xiao-Jing Luo and colleagues at Sun Yat-sen University in China found that overproduction of an RNA molecule called thymopoietin-antisense RNA 1 (TMPO-AS1) in ESCC tissue samples from cancer patients was associated with shorter survival times. Overproduction of this RNA promoted proliferation and spread (metastasis) of the cancer cells. Research on details of the molecular mechanisms involved showed that the RNA ultimately activated the gene that codes for the protein hormone thymopoietin, which has previously been linked with various cancers. The authors suggest that TMPO-AS1 and thymopoietin could serve as diagnostic biomarkers of cancer and become targets for anti-cancer drugs.

The Emerging Role of Thymopoietin-Antisense RNA 1 as Long Noncoding RNA in the Pathogenesis of Human Cancers

Long noncoding RNAs (lncRNAs) play essential roles in the occurrence and development of multiple human cancers. An accumulating body of researches have investigated thymopoietin antisense RNA 1 (TMPO-AS1) as a newly discovered lncRNA, which functions as an oncogenic lncRNA that is upregulated in various human malignancies and associated with poor prognosis. Many studies have detected abnormally high expression levels of TMPO-AS1 in multiple cancers, such as lung cancer, breast cancer, colorectal cancer (CRC), hepatocellular carcinoma, CRC, gastric cancer, ovarian cancer, thyroid cancer, esophageal cancer, Wilms tumor, cervical cancer, retinoblastoma, bladder cancer, osteosarcoma, and prostate cancer. TMPO-AS1 has been subsequently demonstrated to play a pivotal role in tumorigenesis and progression. The aberrantly expressed TMPO-AS1 acts as a competing endogenous RNA (ceRNA) that inhibits miRNA expression, thus activating the expression of downstream oncogenes. This study comprehensively summarizes the aberrant expressions of TMPO-AS1 as reported in the current literature and explains the relevant biological regulation mechanisms in carcinogenesis and tumor progression. Corresponding studies have indicated that TMPO-AS1 has a potential value as a promising biomarker or a target for cancer therapy.

The Long Non-coding RNA TMPO-AS1 Promotes Bladder Cancer Growth and Progression via OTUB1-Induced E2F1 Deubiquitination

Background: Increasing evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in cancer tumorigenesis and progression. TMPO antisense RNA 1 (TMPO-AS1) has been found to be involved in several cancers by acting as a competing endogenous RNA. However, the potential roles of TMPO-AS1 in bladder cancer (BC) and the potential interactions with proteins remain poorly understood.

Methods: The expression of the lncRNA TMPO-AS1 was evaluated via bioinformatic analysis and further validated by quantitative real-time PCR (qRT-PCR). Loss- and gain-of-function assays were performed to determine the biological functions of TMPO-AS1 in BC cell proliferation, migration, and invasion. Moreover, chromatin immunoprecipitation, Western blotting, and fluorescence in situ hybridization, as well as RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays, were conducted to explore the upstream and downstream molecules interacting with TMPO-AS1.

Results: TMPO-AS1 is upregulated in BC. Functional experiments demonstrated that TMPO-AS1 promotes cell proliferation, migration, and invasion in BC and inhibits cell apoptosis in vivo and in vitro. Mechanically, E2F1 is responsible for TMPO-AS1 upregulation. Additionally, TMPO-AS1 facilitates the interaction of E2F1 with OTU domain-containing ubiquitin aldehyde binding 1 (OTUB1), leading to E2F1 deubiquitination and stabilization; therefore, TMPO-AS1 promotes BC malignant phenotypes. Furthermore, rescue experiments showed that TMPO-AS1 promotes BC growth in an E2F1-dependent manner.

Conclusions: Our study is the first to uncover the novel TMPO-AS1/E2F1 positive regulatory loop important for the promotion of BC malignant behaviors. The TMPO-AS1/E2F1 loop should be considered in the quest for new BC therapeutic options.

TMPO-AS1 Regulates the Aggressiveness-Associated Traits of Nasopharyngeal Carcinoma Cells Through Sponging miR-320a

Background

Previous evidence demonstrates that the long non-coding RNA (lncRNA) TMPO antisense RNA 1 (TMPO-AS1) is involved in the aggressiveness of several cancers. Nevertheless, its functions in nasopharyngeal carcinoma (NPC) are unclear.

Methods

qRT-PCR was used to evaluate the levels of TMPO-AS1 and miR-320a in NPC tissues. Furthermore, the growth and invasiveness of NPC cells were evaluated by colony formation and Transwell assays. The protein expression ofSRY-Box Transcription Factor 4 (SOX4) was observed by Western blotting and immunohistochemistry. Bioinformatic prediction and luciferase reporter assays were used to explore the interaction between miR-320a and TMPO-AS1. The transplanted model was employed to disclose the interference of TMPO-AS1 in the tumor growth of NPC cells in vivo.

Results

We found that TMPO-AS1 was distinctly upregulated in NPC. Downregulation of TMPO-AS1 restrained aggressiveness-associated traits in NPC cells. Nevertheless, upregulation of TMPO-AS1 yielded the opposite results. Further studies revealed that lncRNA TMPO-AS1 acts as a “sponge” for miR-320a, resulting in increased levels of SOX4 in NPC cells. Finally, TMPO-AS1 silencing suppressed tumor growth of NPC cells in vivo.

Conclusion

Collectively, these results reveal the presence of a novel TMPO-AS1/miR-320a/SOX4 pathway associated with NPC progression, suggesting that lncRNA TMPO-AS1 may be a potential therapeutic target for NPC.

LncRNA TMPO-AS1 Promotes Proliferation and Invasion by Sponging miR-383-5p in Glioma Cells

Purpose

Glioma is one of the most common malignant tumors affecting human health. Long non-coding RNA (lncRNA) TMPO-AS1 participates in the pathogenesis of various cancers. However, the role of lncRNA TMPO-AS1 in glioma remains largely unknown. This study aims to uncover the role of TMPO-AS1 and explore its potential mechanism in glioma.

Methods

Expression levels of TMPO-AS1 and miR-383-5p in glioma cell lines were measured by real-time quantitative PCR (RT-qPCR). CCK-8, colony formation, wound-healing, and Transwell assays were conducted to determine cell proliferation, migration and invasion abilities, respectively. Western blotting was applied to detect the expression of corresponding proteins. Immunofluorescence assay was performed to measure the expression of Ki67. The binding condition between TMPO-AS1 and miR-383-5p was verified by dual-luciferase reporter assay.

Results

We found that TMPO-AS1 was up-regulated while miR-383-5p was down-regulated in glioma cell lines, and knockdown of TMPO-AS1 significantly suppressed glioma cell proliferation, migration and invasion abilities. miR-383-5p was demonstrated to be a direct target of TMPO-AS1. Besides, inhibition of miR-383-5p abolished the effects of TMPO-AS1 knockdown on glioma cells.

Conclusion

In summary, our study revealed that inhibition of lncRNA TMPO-AS1 could suppress glioma progression through targeting miR-383-5p. TMPO-AS1 might be used as a therapeutic target for glioma treatment.