LncRNA RGMB-AS1 inhibits HMOX1 ubiquitination and NAA10 activation to induce ferroptosis in non-small cell lung cancer

Ferroptosis, an iron-dependent regulated cell death caused by excessive lipid peroxide accumulation, has emerged as a promising therapeutic target in various cancers, including non-small cell lung cancer (NSCLC). In this study, we identified the long non-coding RNA RGMB-AS1 as a key regulator of ferroptosis in NSCLC. Mechanistically, RGMB-AS1 interacted with heme oxygenase 1 (HMOX1) and prevented its ubiquitination by the E3 ligase TRC8, leading to increased HMOX1 stability and enhanced ferroptosis. Additionally, RGMB-AS1 bound to the 82-87 amino acid region of N-alpha-acetyltransferase 10 (NAA10), stimulating its acetyltransferase activity and promoting the conversion of acetyl-CoA to HMG-CoA, further contributing to ferroptosis. The RGMB-AS1-HMOX1 and RGMB-AS1-NAA10 axes synergistically inhibited NSCLC growth both in vitro and in vivo. Clinically, low RGMB-AS1 expression was associated with advanced tumor stage and poor overall survival in NSCLC patients. Furthermore, adeno-associated virus-mediated RGMB-AS1 overexpression significantly suppressed tumor growth in mouse xenograft models. Our findings uncover a novel lncRNA-mediated regulatory mechanism of ferroptosis and highlight the potential of RGMB-AS1 as a prognostic biomarker and therapeutic target in NSCLC.

LncRNA RGMB-AS1 facilitates pancreatic cancer cell proliferation and migration but inhibits cell apoptosis via miR-574-3p/PIM3 axis

Pancreatic cancer (PC) is among the most notorious malignancies worldwide. Long noncoding RNA (lncRNA) repulsive guidance molecule bone morphogenetic protein (BMP) coreceptor b antisense RNA 1 (RGMB-AS1) was an oncogene in glioma. However, the RGMB-AS1 function in PC remains largely unknown. Herein, quantitative real-time polymerase chain reaction was performed to analyze the expression of RGMB-AS1. We determined RGMB-AS1 influence on PC cell malignant behaviors via functional assays. Besides, we applied subcellular fractionation and fluorescence in situ hybridization (FISH) assays to confirm the cellular distribution of RGMB-AS1 in PC cells. We used mechanism assays to detect the regulatory axis of RGMB-AS1 in PC cells. Briefly, the level of RGMB-AS1 expression in PC cells was abnormally high. RGMB-AS1 knockdown impeded PC cell proliferation and migration, but induced cell apoptosis, and RGMB-AS1 overexpression led the opposite consequences. RGMB-AS1 acted as a competing endogenous RNA (ceRNA) to sequester miR-574-3p and thereby regulated Pim-3 proto-oncogene, serine/threonine kinase (PIM3) expression. Conclusively, our work revealed the cancer-promoting function of RGMB-AS1 in PC and that the regulatory mechanism of the RGMB-AS1/miR-574-3p/PIM3 axis might contribute to novel biomarker development in PC treatment.NEW & NOTEWORTHY RGMB-AS1 promotes PC cell proliferation, elevates PC cell migration capacity, inhibits PC cell apoptosis, and promotes PC cell proliferation and migration but inhibits cell apoptosis via targeting miR-574-3p. PIM3 is directly targeted by miR-574-3p.

Long Noncoding RNA RGMB-AS1 Acts as a microRNA-574 Sponge Thereby Enhancing the Aggressiveness of Gastric Cancer via HDAC4 Upregulation

Purpose

The long noncoding RNA RGMB-AS1 plays an important part in the genesis and progression of multiple human cancers. Nonetheless, little is known regarding its expression, roles, and mechanisms of action in gastric cancer (GC). This study was aimed at investigating the relationship between RGMB-AS1 and GC and illustrating the mechanisms of action of RGMB-AS1 therein.

Methods

RGMB-AS1 expression in GC was measured via reverse-transcription quantitative PCR. A series of experiments including Cell Counting Kit-8 assay, flow-cytometric analysis of apoptosis, Transwell migration and invasion assays, and in vivo tumorigenesis experiment were conducted to test the effects of RGMB-AS1 on the malignant phenotype of GC cells. The molecular events behind the oncogenic actions of RGMB-AS1 in GC were elucidated through subcellular fractionation, RNA immunoprecipitation assay, bioinformatics analysis and luciferase reporter assay.

Results

RGMB-AS1 upregulation was confirmed in GC tissues and cell lines. Higher RGMB-AS1 expression was associated with adverse clinical parameters and negatively correlated with patient overall survival. RGMB-AS1 knockdown inhibited GC cell proliferation, facilitated apoptosis, and reduced migration and invasion in vitro. Further experiments revealed that RGMB-AS1 knockdown decreased the tumor growth of GC cells in vivo. Mechanistically, RGMB-AS1 functioned as a competing endogenous RNA upregulating histone deacetylase 4 (HDAC4) by sponging microRNA-574 (miR-574). Rescue experiments indicated that miR-574 inhibition and HDAC4 reintroduction reversed the effects of the RGMB-AS1 knockdown on GC cells.

Conclusion

The RGMB-AS1–miR-574–HDAC4 regulatory network contributes to the malignancy of GC, thereby offering a novel target for the diagnosis, prognosis, and/or treatment of GC.

LncRNA RGMB-AS1 Promotes Glioma Growth and Invasion Through miR-1200/HOXB2 Axis

Background

Dysfunction of long noncoding RNA (lncRNA) is associated with tumorigenesis of various malignancies, including glioma. LncRNA RGMB-AS1 (RGMB antisense RNA 1) has been reported to participate in initiation and progression of several cancers, such as lung cancer, hepatocellular carcinoma and laryngeal squamous cell carcinoma. Nevertheless, whether RGMB-AS1 regulates glioma development is not investigated. In this study, we aimed to determine its roles in glioma.

Methods

qRT-PCR and Western blotting were used to measure gene expression. CCK8 and colony formation assays were utilized to analyze proliferation. Transwell assay was used to determine cell migration and invasion. Luciferase reporter assay was used to validate the interactions among RGMB-AS1, miR-1200 and HOXB2.

Results

RGMB-AS1 was upregulated in glioma tissues and associated with glioma grade and patients' prognosis. Moreover, RGMB-AS1 silencing significantly inhibited the proliferation, migration and invasion of glioma cells. RGMB-AS1 downregulation led to more tumor cells arrested in the quiescent state. Mechanistically, we found that RGMB-AS1 was a molecular sponge for miR-1200. MiR-1200 level was inhibited by RGMB-AS1. And RGMB-AS1 promoted HOXB2 expression via sponging miR-1200. Restoration of HOXB2 effectively rescued the abilities of proliferation, migration and invasion in RGMB-AS1-depleted glioma cells.

Conclusion

Collectively, our work clarified that RGMB-AS1/miR-1200/HOXB2 signaling exerts an essential role in regulating glioma progression.