Mitochondrial ncRNA targeting induces cell cycle arrest and tumor growth inhibition of MDA-MB-231 breast cancer cells through reduction of key cell cycle progression factors

Abstract

The family of long noncoding mitochondrial RNAs (ncmtRNAs), comprising sense (SncmtRNA), and antisense (ASncmtRNA-1 and ASncmtRNA-2) members, are differentially expressed according to cell proliferative status; SncmtRNA is expressed in all proliferating cells, while ASncmtRNAs are expressed in normal proliferating cells, but is downregulated in tumor cells. ASncmtRNA knockdown with an antisense oligonucleotide induces massive apoptosis in tumor cell lines, without affecting healthy cells. Apoptotic death is preceded by proliferation blockage, suggesting that these transcripts are involved in cell cycle regulation. Here, we show that ASncmtRNA knockdown induces cell death preceded by proliferative blockage in three different human breast cancer cell lines. This effect is mediated by downregulation of the key cell cycle progression factors cyclin B1, cyclin D1, CDK1, CDK4, and survivin, the latter also constituting an essential inhibitor of apoptosis, underlying additionally the onset of apoptosis. The treatment also induces an increase in the microRNA hsa-miR-4485-3p, whose sequence maps to ASncmtRNA-2 and transfection of MDA-MB-231 cells with a mimic of this miRNA induces cyclin B1 and D1 downregulation. Other miRNAs that are upregulated include nuclear-encoded hsa-miR-5096 and hsa-miR-3609, whose mimics downregulate CDK1. Our results suggest that ASncmtRNA targeting blocks tumor cell proliferation through reduction of essential cell cycle proteins, mediated by mitochondrial and nuclear miRNAs. This work adds to the elucidation of the molecular mechanisms behind cell cycle arrest preceding tumor cell apoptosis induced by ASncmtRNA knockdown. As proof-of-concept, we show that in vivo knockdown of ASncmtRNAs results in drastic inhibition of tumor growth in a xenograft model of MDA-MB-231 subcutaneous tumors, further supporting this approach for the development of new therapeutic strategies against breast cancer.

Competitive endogenous RNA network reveals that miR-1343 play key regulatory roles in longissimus dorsi muscle between Saba and Yorkshire pigs

“…NcRNAs are non-coding parts of genome at different cell status, and account for more than 90% RNA transcripts [43]. Increasing data have demonstrated that ncRNAs played the important regulatory roles in many biological processes such as sex differentiation [44], organ development [45], and tumor origination and progression [46]. More and more studies revealed that ncRNAs played regulatory roles by ceRNA network on the basis of ceRNA hypothesis [21], and utilizing ceRNA network analysis have identified a lot of regulatory factors including lncRNAs, miRNAs and cirRNAs associated with some animal economic traits such as hair follicle cycle of cashmere goat and poultry meat quality [27,47].…”

Crosstalk of lncRNA and Cellular Metabolism and Their Regulatory Mechanism in Cancer

“…Moreover, the E2 oncogene is involved in this regulation [61]. Fitzpatrick et al demonstrated that the knockdown of ASncmtRNA induced cell death and inhibited tumor growth via cell cycle-related genes, such as cyclin B1, cyclin D1, CDK1, CDK4, and surviving in breast cancer cell lines [62]. Thus, these findings shed light on the functional role of ASncmtRNA in cancer progression.…”

“…Chimeric lncRNAs containing mtDNA-encoded genes have been characterized. Sense mitochondrial ncRNA (SncmtRNA) is expressed in proliferating cells, including normal and cancer cells, but not in resting cells [61,62]. SncmtRNA has a characteristic RNAse-resistant double-stranded structure with a 40-nucleotide loop.…”

“…The therapeutic repression of NATs such as ANRIL and p21-AS by treating with a specific ASO can induce the overlapping tumor suppressor genes expression [101,102]. The knockdown of ASncmtRNA by ASO resulted in the dramatic inhibition of cell proliferation and tumor growth in vitro and in a xenograft model [62]. Gone et al demonstrated that specific ASO-MALAT1 treatment reduced its expression in lung cancer cells and inhibited cell migration ability [103].…”

<strong>Think Different with RNA Therapy: Can Antisense Oligonucleotides Be Used to Inhibit Replication and Transcription of SARS-Cov-2?</strong>

“…Antisense RNA therapy is an emerging topic of translational research in medicine and currently the focus of many clinical trials in cancers, myopathies, Huntington's disease and many other diseases (Crooke et al, 2018). For example, a phase 1b clinical assay is currently under way for the treatment of solid cancers by an antisense oligonucleotide targeted to ASncmtRNA (Burzio et al, 2009;Lobos-González et al, 2016;Fitzpatrick et al, 2019;ClinicalTrials Identifier: NCT03985072). All these examples of ASOs in clinical trials show that the concept of antisense RNA therapy is coming of age and will be developed further in the near future thanks to its low toxicity, high specificity and low production cost.…”