Mechanism of LncRNA FTX regulates nephroblastoma progression through MiR-215-5p/PI3K/AKT axis

BACKGROUND

Nephroblastoma, also more commonly known as Wilms tumor (WT), is a common childhood malignancy that connects tumorigenesis and organ development in the kidney.

OBJECTIVE

The current study focused on the effect of lncRNA FTX in nephroblastoma.

STUDY DESIGN

Expression of lncRNA FTX in nephroblastoma tissues and cells was determined. The expression location of lncRNA FTX was detected by FISH. The binding of lncRNA FTX and miR-215-5p with Ago2 was verified by RIP. Following gain- and loss-of-function approaches, the crucial role of lncRNA FTX and miR-215-5p in nephroblastoma cell functions was measured with the involvement of the PI3K/AKT pathway.

RESULTS

LncRNA FTX was elevated and miR-215-5p was declined in nephroblastoma. Silencing of lncRNA FTX or mimic of miR-215-5p inhibited the malignant properties of nephroblastoma cells. LncRNA FTX was localized in the cytoplasm and might bind miR-215-5p. LncRNA FTX promoted the malignant features of nephroblastoma cells by inhibiting miR-215-5p through activating of the PI3K/AKT pathway.

CONCLUSIONS

LncRNA FTX is capable of accelerating nephroblastoma development in vitro by reducing miR-215-5p through activating of the PI3K/AKT pathway, indicating LncRNA FTX may possibly a future target for the diagnosis and treatment of nephroblastoma. SUMMARY FIGURE.

LncRNA FTX Inhibits Ferroptosis of Hippocampal Neurons Displaying Epileptiform Discharges In vitro Through the miR-142-5p/GABPB1 Axis

Epilepsy is a disabling and drug-refractory neurological disorder. Long non-coding RNAs (lncRNAs) play a vital role in neuronal function and central nervous system development. This study aimed to explore the regulatory mechanism of lncRNA five prime to Xist (FTX) in cell ferroptosis following epilepsy to provide a theoretical foundation for epilepsy management. Hippocampal neurons were isolated from brain tissues of healthy male SD rats, and an in vitro cell model of epilepsy was established using magnesium-free (MGF) induction. Patch-clamp technique was used to determine the action potentials of neurons. Neuronal viability and apoptosis were assessed by CCK-8 assay and flow cytometry. Levels of FTX, miR-142-5p, and GABPB1 were determined by RT-qPCR and Western blot, respectively. The cellular location of FTX was predicted and validated by RNA immunoprecipitation. Dual-luciferase assay verified targeting relationships among FTX, miR-142-5p, and GAPBP1. Levels of ferroptosis indicators and ferroptosis-related proteins were measured using Western blot and corresponding kits. Neuronal ferroptosis and apoptosis increased after MGF induction, and FTX was weakly-expressed in MGF-induced neurons. FTX overexpression attenuated ferroptosis and apoptosis of MGF-induced neurons. miR-142-5p was upregulated after MGF induction and downregulated after FTX overexpression, and FTX targeted miR-142-5p. miR-142-5p overexpression partially negated the inhibitory action of FTX overexpression on ferroptosis of MGF-induced neurons. FTX regulated GABPB1 expression by targeting miR-142-5p. In conclusion, FTX overexpression mitigated ferroptosis of MGF-induced neurons through the miR-142-5p/GABPB1 axis. In conclusion, lncRNA FTX inhibited ferroptosis of MGF-induced rat hippocampal neurons via the miR-142-5p/GABPB1 axis.

Prognostic significance of long non-coding RNA five prime to XIST in various cancers

BACKGROUND

To observe the clinicopathological and prognostic value of long non-coding RNA five prime to X inactive specific transcript (lncFTX) in multiple tumors.

METHODS

Eligible studies for lncFTX were identified by searching PubMed, Embase, Web of Science and Cochrane Library databases from inception to December 01, 2020. Stata 12.0 software was used to calculate the odds ratio (OR)/hazard ratio (HR) and 95% confidence interval (95% CI). We used The Cancer Genome Atlas (TCGA) dataset to further investigate the differential expression and prognostic value of lncFTX.

RESULTS

We included 11 studies involving a total of 1633 patients. The results showed that the expression of lncFTX was positively associated with advanced TNM stage (III-IV versus I-II) (OR = 2.30, 95% CI: 1.74-3.03, P < 0.05), lymph nodes metastasis (OR = 3.01, 95% CI: 2.00-4.52, P < 0.05), distant metastasis (OR = 3.68, 95% CI: 2.13-6.34, P < 0.05), and cancer mortality (HR = 1.83, 95% CI: 1.20-2.81, P < 0.05). However, the expression of lncFTX was not associated with tumor differentiation (poor differentiation versus well or moderate differentiation) and vessel invasion of cancer. Subgroup analysis showed that the higher lncFTX expression was associated with shorter overall survival in cancer patients, regardless of the sample size and cancer type. No publication bias was found, and the sensitivity analysis results suggested that the main findings were robust. Elevated expression and prognostic significance of FTX were confirmed using TCGA dataset.

CONCLUSIONS

This study found that the expression of lncFTX was positively associated with advanced tumor node metastasis (TNM) stage, lymph nodes, distant metastasis and, cancer mortality, suggesting that lncFTX might be a potential prognostic biomarker for tumors.

The Function of LncRNA FTX in Several Common Cancers

BACKGROUND

LncRNA is a kind of non-coding RNA and its research is more popular in recent years, which has more than 200 nucleotides. It plays a significant part in various biological functions, including chromosome modification, genome modification, transcriptional activation, transcriptional interference, and other processes. FTX, at the center of the X chromosome inactivation and it has been shown that lncRNA FTX regulates cancer cells' development, migration, and invasion in many studies.

METHODS

Relevant literature was collected through the PubMed system search and is summarized in this article.

RESULTS

LncRNA FTX abnormally increased in tumor cells, such as liver cancer, stomach cancer, leukemia, renal cell carcinoma, colorectal cancer, glioma, osteosarcoma, etc. However, the expression level decreased in temporal lobe epilepsy, liver cirrhosis, heart failure, etc. Conclusion: FTX may be an important regulatory factor and a potential therapeutic target in cancers.

LncRNA FTX Promotes Colorectal Cancer Cells Migration and Invasion by miRNA-590-5p/RBPJ Axis

Colorectal cancer (CRC) is one of the most lethal human cancers all over the world. Moreover, it ranks fourth for cancer-related deaths among males. Although many efforts have been made to cure CRC, the effect remains limited. It has been reported that lncRNA five prime to Xist (FTX) was upregulated in CRC. However, the mechanism by which lncRNA FTX regulates the progression of CRC remains largely unknown. In this study, qRT-PCR was performed to detect the expression of FTX, miR-590-5p and Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) in CRC tissues or cells. Protein expression in cells was measured by western blot. MTT assay was used to test the cell viability. Moreover, transwell was performed to examine the cell migration and invasion. Luciferase report assay was performed to verify the relation between miR-590-5p and FTX or RBPJ. It was found that FTX was upregulated in CRC tissues and cells. Knockdown of FTX or overexpression of miR-590-5p can inhibit the proliferation, migration, and invasion of CRC cells. Besides, silencing of FTX could inhibit the expression of migration and invasion-related proteins in CRC cells. Meanwhile, miR-590-5p was the target of FTX, and RBPJ was the direct target of miR-590-5p. Inhibition of miR-590-5p could reverse the inhibitory effect of FTX on the progression of CRC. These findings suggested that knockdown of FTX could inhibit the tumorigenesis of CRC in vitro, which may serve as a potential novel strategy for treatment of CRC.

LncRNA FTX Involves in the Nogo-66-Induced Inhibition of Neurite Outgrowth Through Regulating PDK1/PKB/GSK-3β Pathway

Nogo-66 can inhibit neurite outgrowth, while its regulation mechanisms have not been fully elucidated. Recent studies prove that lncRNAs are involved in neurite outgrowth. This study was aimed to investigate whether lncRNA FTX was involved in Nogo-66-induced inhibition of neurite outgrowth and explore the potential mechanism. The expression of relative genes was detected by qRT-PCR and western blot. The function of FTX was determined by overexpression and knockdown techniques. The interaction between FTX and PDK1 was evaluated by RIP and RNA pull-down assays. FTX expression was downregulated by Nogo-66 in PC12 cells. Nogo-66-induced inhibition of neurite outgrowth was relieved by FTX overexpression. FTX bound to PDK1 protein to disturb the interaction between PDK1 and E3 ubiquitin ligase RNF126, thereby blocked the ubiquitination degradation of PDK1 and elevated PDK1 protein level. Mechanically, FTX involved in the Nogo-66-induced inhibition of neurite outgrowth through the PDK1/PKB/GSK-3β pathway. In SCI rats, FTX knockdown inhibited neurite outgrowth induced by the receptor antagonist of Nogo-66. The present results suggested that FTX took part in Nogo-66-inhibited neurite outgrowth, and FTX exerted its function through regulating PDK1/PKB/GSK-3β pathway.

LncRNA FTX Promotes Proliferation and Invasion of Gastric Cancer via miR-144/ZFX Axis

BACKGROUND

Long non-coding RNAs are important regulators in cancer cell tumorigenesis. We have demonstrated in a prior study that lncRNA FTX is dysregulated in gastric cancer (GC). In this study, we aim to report gastric cancer-related lncRNA FTX as a main regulator in GC development and progression.

METHODS

In vitro and in vivo assays of FTX alterations have been performed to reveal a complex integrated phenotype affecting cell growth, migration, and invasion. lncRNA FTX expression levels in gastric cancer cells and normal cells were measured by RT-PCR. Luciferase reporter assays, Western blotting, and many immune, microscopy technologies were utilized to investigate the expressions of FTX- related proteins and RNAs. The functional role of FTX in cell growth, migration, and invasion were observed in vitro and in vivo.

RESULTS

We explored the underlying mechanisms of FTX in GC development, and the microRNAs' relationship with FTX. We found that FTX promoted cell proliferation, migration, and invasion, as well as tumor growth, and this effect could latterly be attenuated by miR-144. ZFX attenuated the effects of FTX/miR-144 axis by sponging with miR-144.

CONCLUSION

In summary, the above results support a model in which the FTX/miR-144/ZFX act as important effectors in GC tumorigenesis and progression, indicating new therapeutic methods in GC.