Long Noncoding RNA HCG11 Acts as a Tumor Suppressor in Gastric Cancer by Regulating miR-942-5p/BRMS1 Axis

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

lncRNA HCG11 Promotes Colorectal Cancer Cell Malignant Behaviors via Sponging miR-26b-5p

Colorectal cancer (CRC) is a type of gastrointestinal cancer with an increasing incidence. Long noncoding RNAs (lncRNAs) have raised great concern because of wide participation in human diseases, including cancers. However, whether lncRNA HLA complex group 11 (HCG11) played a functional role in CRC remained to be elucidated. Herein, we utilized qRT-PCR to analyze the expression of HCG11 and found that HCG11 was highly expressed in CRC cells. Besides, HCG11 knockdown suppressed cell proliferation, migration, and invasion but facilitated cell apoptosis. Furthermore, supported by bioinformatics analyses and mechanism assays, HCG11, mainly located in cell cytoplasm, was confirmed to competitively bind to miR-26b-5p to modulate the expression of the target messenger RNA (mRNA), namely, cAMP-regulated phosphoprotein 19 (ARPP19). ARPP19 was detected to be upregulated in CRC cells, and ARPP19 silence was verified to inhibit the malignant behaviors of CRC cells. Rescue experiments validated that miR-26b-5p inhibition or ARPP19 overexpression could countervail the inhibitory influences of HCG11 silence on CRC cell biological behaviors in vitro. To conclude, HCG11, upregulated in CRC cells, could promote cell proliferation, migration, and invasion and inhibit cell apoptosis via targeting miR-26b-5p/ARPP19 axis.

CircGSAP regulates the cell cycle of pulmonary microvascular endothelial cells via the miR-942-5p sponge in pulmonary hypertension

Background We recently demonstrated that circGSAP was diminished in lung tissues from patients with pulmonary arterial hypertension and in hypoxia-induced pulmonary microvascular endothelial cells (PMECs). However, the underlying role of circGSAP in PMECs remains unknown. The study aimed to investigate the contribution of circGSAP to proliferation, apoptosis and cell cycle of PMECs in hypoxic environment and explore the mechanism.

Methods The expression of circGSAP was quantified by real-time PCR or immunofluorescence in human lung tissue and PMECs. CircGSAP plasmid, circGSAP small interfering RNA (siRNA), miRNA inhibitor and target gene siRNA were synthesized to verify the role of circGSAP on regulating the proliferation, apoptosis, and cell cycle of PMECs.

Results CircGSAP levels were decreased in lungs and plasma of patients with pulmonary hypertension second to chronic obstructive pulmonary disease (COPD-PH) and were associated with poor outcomes of COPD-PH patients. Upregulation of circGSAP inhibited proliferation, apoptosis resistance and G1/S transition of PMECs. Dual luciferase reporter assays showed that circGSAP acted as a competitive endogenous RNA regulating miR-942-5p, and identified SMAD4 as a target gene of miR-942-5p, Then, we verified the functions of miR-942-5p and SMAD4 in PMECs. In addition, the effect of circGSAP siRNA on PMECs was mitigated by transfection of miR-942-5p inhibitor, and the effect of miR-942-5p inhibitor on PMECs was inhibited by SMAD4 siRNA.

Conclusion Our findings demonstrated that diminished circGSAP accelerated cell cycle to facilitate cell proliferation and apoptosis resistance through competitively binding miR-942-5p to modulate SMAD4 expressions in hypoxia-induced PMECs, indicating potential therapeutic strategies for PH.