TERRA G-quadruplex stabilization as a new therapeutic strategy for multiple myeloma

Abstract

Background Multiple myeloma (MM) is a hematologic malignancy characterized by high genomic instability, and telomere dysfunction is an important cause of acquired genomic alterations. Telomeric repeat-containing RNA (TERRA) transcripts are long non-coding RNAs involved in telomere stability through the interaction with shelterin complex. Dysregulation of TERRAs has been reported across several cancer types. We recently identified a small molecule, hit 17, which stabilizes the secondary structure of TERRA. In this study, we investigated in vitro and in vivo anti-MM activities of hit 17. Methods Anti-proliferative activity of hit 17 was evaluated in different MM cell lines by cell proliferation assay, and the apoptotic process was analyzed by flow cytometry. Gene and protein expressions were detected by RT-qPCR and western blotting, respectively. Microarray analysis was used to analyze the transcriptome profile. The effect of hit 17 on telomeric structure was evaluated by chromatin immunoprecipitation. Further evaluation in vivo was proceeded upon NCI-H929 and AMO-1 xenograft models. Results TERRA G4 stabilization induced in vitro dissociation of telomeric repeat‐binding factor 2 (TRF2) from telomeres leading to the activation of ATM-dependent DNA damage response, cell cycle arrest, proliferation block, and apoptotic death in MM cell lines. In addition, up-regulation of TERRA transcription was observed upon DNA damage and TRF2 loss. Transcriptome analysis followed by gene set enrichment analysis (GSEA) confirmed the involvement of the above-mentioned processes and other pathways such as E2F, MYC, oxidative phosphorylation, and DNA repair genes as early events following hit 17-induced TERRA stabilization. Moreover, hit 17 exerted anti-tumor activity against MM xenograft models. Conclusion Our findings provide evidence that targeting TERRA by hit 17 could represent a promising strategy for a novel therapeutic approach to MM.

Exosc9 Initiates SUMO-Dependent lncRNA TERRA Degradation to Impact Telomeric Integrity in Endocrine Therapy Insensitive Hormone Receptor-Positive Breast Cancer

“…In several telomerase-positive cancers, TERRA is a tumor suppressor [13][14][15] and is consistent with TERRA's function to inhibit telomerase activity [6]. In murine mammary epithelial cells, TERRA represses the expression of epithelial-mesenchymal transition genes [16], highlighting the protective role of TERRA against metastatic transformation.…”

LNA-i-miR-221 activity in colorectal cancer: A reverse translational investigation

“…Mice were then randomly divided into two groups (five mice per group) and daily treated with 25 mg/kg of LNA-i-miR-221 or LNA-scramble via intraperitoneal injection as previously described. 67 , 68 Tumor volume was assessed every 2 days via digital caliper measurements. When the size of the tumor reached 2 cm in diameter, the animals were euthanized and tumors were retrieved and stored in RNA Later for subsequent RNA extraction or at −80°C for subsequent WB analysis.…”

Long Telomeric Repeat-Containing RNA (TERRA): Biological Functions and Challenges in Vascular Aging and Disease

“…Moreover, stabilizing the G4 structures of TERRA by using small-molecule ligands (e.g., BRACO-19, Telomestatin) may be one of the most promising approaches to inhibiting telomerase and hence inhibiting the proliferation of cancer cells and tumor growth [60,61]. Indeed, a recent in vitro and in vivo studies have shown that targeting TERRA using hit 17, a small molecule that can bind and stabilize the G4 conformation, could represent a promising strategy for a novel therapeutic approach to multiple myeloma [62]. Additionally, the use of a telomeric antisense oligonucleotide has been recently shown to selectively inhibit the DNA damage response in telomeres in both cells and mice, reducing the markers of cellular senescence apoptosis and the expression of SASP cytokines, as well as improving health and lifespan in an animal model [63,64].…”