LncRNA TUG1 Promotes Hepatocellular Carcinoma Migration and Invasion Via Targeting miR-137/AKT2 Axis

The role of competing endogenous RNA network in the development of hepatocellular carcinoma: potential therapeutic targets

The current situation of hepatocellular carcinoma (HCC) management is challenging due to its high incidence, mortality, recurrence and metastasis. Recent advances in gene genetic and expression regulation have unveiled the significant role of non-coding RNA (ncRNA) in various cancers. This led to the formulation of the competing endogenous RNA (ceRNA) hypothesis, which posits that both coding RNA and ncRNA, containing miRNA response elements (MRE), can share the same miRNA sequence. This results in a competitive network between ncRNAs, such as lncRNA and mRNA, allowing them to regulate each other. Extensive research has highlighted the crucial role of the ceRNA network in HCC development, impacting various cellular processes including proliferation, metastasis, cell death, angiogenesis, tumor microenvironment, organismal immunity, and chemotherapy resistance. Additionally, the ceRNA network, mediated by lncRNA or circRNA, offers potential in early diagnosis and prevention of HCC. Consequently, ceRNAs are emerging as therapeutic targets for HCC. The complexity of these gene networks aligns with the multi-target approach of traditional Chinese medicine (TCM), presenting a novel perspective for TCM in combating HCC. Research is beginning to show that TCM compounds and prescriptions can affect HCC progression through the ceRNA network, inhibiting proliferation and metastasis, and inducing apoptosis. Currently, the lncRNAs TUG1, NEAT1, and CCAT1, along with their associated ceRNA networks, are among the most promising ncRNAs for HCC research. However, this field is still in its infancy, necessitating advanced technology and extensive basic research to fully understand the ceRNA network mechanisms of TCM in HCC treatment.

Functional roles of lncRNA-TUG1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) or hepatoma is malignant cancer that starts from the main liver cells. Although various classical methods have been used for patients with HCC, various molecular mechanisms involved in HCC progression should be invested. Previous studies demonstrated that abnormal expression of long non-coding RNAs (lncRNAs) presented important roles in the pathogenesis of HCC cells. LncRNA TUG1 was found to mediate HCC cell growth, EMT, and metastasis. Therefore, targeting TUG1 and its downstream genes may be a suitable approach for patients with HCC. In this review, we summarized the potential roles of TUG1 in HCC.

LncRNA FGD5-AS1 potentiates autophagy-associated doxorubicin resistance by regulating the miR-154-5p/WNT5A axis in osteosarcoma

Osteosarcoma is prevalent in children and adolescent. The oncogenic function of long-chain noncoding RNA (lncRNA) FGD5 antisense RNA 1 (FGD5-AS1) has been reported. However, the function of FGD5-AS1 in doxorubicin-resistance in osteosarcoma remains to be illucidated. Quantitative real-time PCR (qRT-PCR) and western blot analysis (WB) were used to measure the expression of FGD5-AS1, miR-154-5p, WNT5A and autophagy proteins. MTT assay was used to assess cell viability and transwell assay was performed to evaluate migration. A nude mouse xenograft model was developed to verify the function of FGD5-AS1 in vivo. FGD5-AS1 was upregulated in doxorubicin-resistant (DXR) osteosarcoma cells. Knockdown of FGD5-AS1 suppressed osteosarcoma cell proliferation, migration, and autophagy. FGD5-AS1 upregulated WNT5A expression via sponging miR-154-5p. Furthermore, FGD5-AS1 enhanced osteosarcoma cell chemotherapy resistance through upregulation of WNT5A by inhibiting miR-154-5p. Suppression of FGD5-AS1 significantly suppressed tumor growth in nude mice. FGD5-AS1 may promote chemoresistance through WNT5A-induced autophagy by sponging miR-154-5p in osteosarcoma cells.

LncRNA ZNF674-AS1 Hinders Proliferation and Invasion of Hepatic Carcinoma Cells through the Glycolysis Pathway

Purpose. Long noncoding RNAs (lncRNAs) play important roles in regulating various functions of cells at the levels of transcription and posttranscription. Extensive investigations have illustrated that lncRNAs are critical in the glucose metabolism of tumor cells, but their mechanisms of action need to be further explored. This study evaluates the role of lncRNA ZNF674-AS1 on the apoptosis and proliferation of human hepatic carcinoma cells in vitro through the glucose metabolism and its related mechanisms. Methods. Real-time quantitative PCR was employed for detecting the level of expressions for lncRNA ZNF674-AS1 in liver cancer tissues (25 cases), paracancerous tissues, and liver cancer cell lines. The lncRNA ZNF674-AS1 high expression cell strain was constructed by the lentiviral overexpression vector. CCK-8, plate colony formation, transwell assay, lactate production, glucose consumption, and ATP levels were used to detect the change of cell proliferation, colony formation, migration, and invasion, as well as glycolytic capability. Western blot was carried out to detect the expression of HK2, PFKL, PKM2, GLUT1, and PKM1, which are the key proteins of glycolysis in cells. Result. The lncRNA ZNF674-AS1 was undesirably expressed in liver cancer cell lines and tissues. Cell function assessments showed that compared with the blank control group (vector), overexpression of lncRNA ZNF674-AS1 could substantially hinder the proliferation, colony formation, migration, and invasion capability of liver cancer cells. Furthermore, overexpression of lncRNA ZNF674-AS1 could inhibit cell glycolysis (inhibit glucose consumption and reduce intracellular lactate and ATP levels) by inhibiting the expression of key proteins (such as PFKL, HK2, PKM2, and GLUT1) in the process of glycolysis. Conclusion. As a tumor repressor gene, lncRNA ZNF674-AS1 inhibits the expression of key proteins in glycolysis to inhibit glycolysis level, thereby inhibiting cell migration and proliferation. Therefore, lncRNA ZNF674-AS1 could be a potent therapeutic target or a novel diagnostic molecule for patients suffering from liver cancer.

Long Noncoding RNA TUG1 Inhibits Tumor Progression through Regulating Siglec-15-Related Anti-Immune Activity in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death, and its biology remains poorly understood, especially in regards to the immunosuppression induced by immune checkpoints, such as Siglec-15. Most cancer treatments composed of immune checkpoint inhibitors and oncogene-targeted drugs display a better therapeutic effect in the clinic, including tumor progression inhibition and immunosuppression breaks. However, two or more drugs will result in a greater possibility of adverse effects. Thus, a double-function target is necessary for developing antitumor drugs, such as RNAi therapy.

Methods

The expression of TUG1, Siglec-15, and miRNAs was evaluated by qPCR, and protein expression was analyzed by western blotting. The immune responses were evaluated by a Jurkat-reporter gene assay, a T cell-induced cytotoxicity assay, and IFN-γ/IL-2 release. The interactions among TUG1, Siglec-15, and miRNAs were verified by dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. CCK-8 and Transwell assays were used to determine tumor cell proliferation, migration, and invasion.

Results

In HCC patients and cells, increased TUG1 levels were observed, positively regulating Siglec-15 expression. TUG1-induced Siglec-15 upregulation resulted in the suppression of the immune response of HCC cells. hsa-miR-582-5p directly targeted TUG1 and Siglec-15 mRNA, and ihsa-miR-582-5p knockout prevented the regulation of Siglec-15 induced by THU1. Changes in hsa-miR-582-5p expression negatively regulated Siglec-15 levels and immunosuppression but had no influence on TUG1 levels. siRNA knockdown of TUG1 effectively led to tumor progression inhibition and immune response improvement in HCC cells both in vitro and in vivo.

Conclusion

TUG1 increases the Siglec-15 level in HCC cells as a sponge to hsa-miR-582-5p, resulting in enhanced immunosuppression. TUG1 knockdown induced by siRNA not only reduces immunosuppression but also suppresses tumor progression both in vitro and in vivo. These novel findings may provide a potential and appropriate target for RNAi therapy to develop drugs with dual antitumor activity.

LncRNA-TUG1 promotes the progression of infantile hemangioma by regulating miR-137/IGFBP5 axis

Background

Previous studies indicated that lncRNA taurine upregulated gene 1 (TUG1) played essential roles in human cancers. This study aimed to investigate its function in infantile hemangioma (IH).

Methods

A total of 30 pairs of clinical infantile specimens were used in this study. The expression of TUG1 in IH tissues was assessed by quantitative reverse transcriptase PCR (qRT-PCR). Two short hairpin RNA targeting TUG1 (sh-TUG1-1 and sh-TUG1-2) were transfected into hemangioma-derived endothelial cells, HemECs, to block its expression. The effects of TUG1 on HemECs were evaluated by Cell Counting Kit-8 (CCK-8), colony formation assay, wound healing assay, and Transwell assay. The underlying molecular mechanism of TUG1 was investigated by Starbase prediction and luciferase reporter assay and further determined by loss- and gain-of-function approaches. In addition, the role of TUG1 on tumorigenesis of HemECs was confirmed in an in vivo mouse model.

Results

TUG1 was significantly upregulated in infant hemangioma tissues compared with normal adjacent subcutaneous tissues. The loss- and gain-of-function approaches indicated that TUG1 overexpression promoted proliferation, migration, and invasion of HemECs in vitro, and TUG1 knockdown inhibited the tumorigenesis of HemECs in vivo. Specifically, TUG1 could compete with IGFBP5 for miR137 binding. Rescue experiments further confirmed the role of the TUG1/miR137/IGFBP5 axis in HemECs.

Conclusion

TUG1 was closely associated with the progression of IH by regulating the miR-137/IGFBP5 axis, which might be a potential target for IH treatment.

Circular RNA circPVT1 Contributes to Doxorubicin (DXR) Resistance of Osteosarcoma Cells by Regulating TRIAP1 via miR-137

Background

Chemoresistance is a major obstacle to the treatment of osteosarcoma patients. Circular RNA (circRNA) circPVT1 has been reported to be related to the doxorubicin (DXR) resistance in osteosarcoma. This study is designed to explore the role and mechanism of circPVT1 in the DXR resistance of osteosarcoma.

Methods

circPVT1, microRNA-137 (miR-137), and TP53-regulated inhibitor of apoptosis 1 (TRIAP1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The protein levels of ATP-binding cassette, subfamily C, member 1 (ABCC1), multidrug resistance-associated protein 1 (MRP-1), cleaved- (c-) caspase-3, B-cell lymphoma-2 (Bcl-2), and TRIAP1 were examined by a western blot assay. Cell viability, proliferation, and apoptosis were detected by cell counting kit-8 (CCK-8), colony formation, and flow cytometry assays, severally. The binding relationship between miR-137 and circPVT1 or TRIAP1 was predicted by starbase 3.0 and then verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. The biological role of circPVT1 in osteosarcoma tumor growth and drug resistance was examined by the xenograft tumor model in vivo. Results. circPVT1 and TRIAP1 were highly expressed, and miR-137 was decreased in DXR-resistant osteosarcoma tissues and cells. Moreover, circPVT1 knockdown could boost DXR sensitivity by inhibiting DXR-caused proliferation and DXR-induced apoptosis in DXR-resistant osteosarcoma cells in vitro. The mechanical analysis discovered that circPVT1 acted as a sponge of miR-137 to regulate TRIAP1 expression. circPVT1 silencing increased the drug sensitivity of osteosarcoma in vivo. Conclusion. circPVT1 boosted DXR resistance of osteosarcoma cells partly by regulating the miR-137/TRIAP1 axis, hinting a promising therapeutic target for the osteosarcoma treatment.

Knockdown of long non-coding RNA TPT1-AS1 inhibits invasion and migration of hepatocarcinoma cells

BACKGROUND

The long non-coding RNA (lncRNA) TPT1-AS1 has been proved to affect the migration and invasion of tumor cells by different means, but its specific role and related mechanisms in hepatic carcinoma still need further research.

AIM

To investigate the expression of TPT1-AS1 in hepatocarcinoma tissues and cell lines and explore its biological role in the invasion and migration of hepatocarcinoma cells.

METHODS

Real-time quantitative PCR was used to measure lncRNA TPT1-AS1 expression in hepatocarcinoma tissue and cell lines (Huh7, SMMC-7721, HCCLM3, and HepG2). After being transfected with small interfering RNA (siRNA-TPT1-AS1), the invasion and migration of HepG2 cells were detected by transwell assay and wound healing assay. Western blot was used to measure the epithelial-mesenchymal transition (EMT) process and the activity of the PI3K/AKT pathway.

RESULTS

TPT1-AS1 was up-regulated in hepatopcarcinoma tissues and cell lines Huh7, SMMC-7721, HCCLM3, and HepG2. Transfection with siRNA-TPT1-AS1 noticeably restrained HepG2 cell invasion and migration, and suppressed the EMT process. Furthermore, TPT1-AS1 knockdown reduced MMP-9 expression and inhibited the activation of the PI3K/AKT pathway.

CONCLUSION

TPT1-AS1 is up-n regulated in hepatic carcinoma. Knockdown of TPT1-AS1 inhibits the invasion and migration of HepG2 cells via mechanisms that may be associated with reducing the activity of PI3K/AKT pathway and the expression of its downstream gene MMP-9, and inhibiting the EMT process.

Hepigenetics: A Review of Epigenetic Modulators and Potential Therapies in Hepatocellular Carcinoma

Hepatocellular carcinoma is the fifth most common cancer worldwide and the second most lethal, following lung cancer. Currently applied therapeutic practices rely on surgical resection, chemotherapy and radiotherapy, or a combination thereof. These treatment options are associated with extreme adversities, and risk/benefit ratios do not always work in patients' favor. Anomalies of the epigenome lie at the epicenter of aberrant molecular mechanisms by which the disease develops and progresses. Modulation of these anomalous events poses a promising prospect for alternative treatment options, with an abundance of felicitous results reported in recent years. Herein, the most recent epigenetic modulators in hepatocellular carcinoma are recapitulated on.