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Quadruplex-forming oligonucleotide targeted to the VEGF promoter inhibits growth of non-small cell lung cancer cells.
- Source :
-
PloS one [PLoS One] 2019 Jan 25; Vol. 14 (1), pp. e0211046. Date of Electronic Publication: 2019 Jan 25 (Print Publication: 2019). - Publication Year :
- 2019
-
Abstract
- Background: Vascular endothelial growth factor (VEGF) is commonly overexpressed in a variety of tumor types including lung cancer. As a key regulator of angiogenesis, it promotes tumor survival, growth, and metastasis through the activation of the downstream protein kinase B (AKT) and extracellular signal-regulated kinase (ERK 1/2) activation. The VEGF promoter contains a 36 bp guanine-rich sequence (VEGFq) which is capable of forming quadruplex (four-stranded) DNA. This sequence has been implicated in the down-regulation of both basal and inducible VEGF expression and represents an ideal target for inhibition of VEGF expression.<br />Results: Our experiments demonstrate sequence-specific interaction between a G-rich quadruplex-forming oligonucleotide encoding a portion of the VEGFq sequence and its double stranded target sequence, suggesting that this G-rich oligonucleotide binds specifically to its complementary C-rich sequence in the genomic VEGF promoter by strand invasion. We show that treatment of A549 non-small lung cancer cells (NSCLC) with this oligonucleotide results in decreased VEGF expression and growth inhibition. The VEGFq oligonucleotide inhibits proliferation and invasion by decreasing VEGF mRNA/protein expression and subsequent ERK 1/2 and AKT activation. Furthermore, the VEGFq oligonucleotide is abundantly taken into cells, localized in the cytoplasm/nucleus, inherently stable in serum and intracellularly, and has no effect on non-transformed cells. Suppression of VEGF expression induces cytoplasmic accumulation of autophagic vacuoles and increased expression of LC3B, suggesting that VEGFq may induce autophagic cell death.<br />Conclusion: Our data strongly suggest that the G-rich VEGFq oligonucleotide binds specifically to the C-rich strand of the genomic VEGF promoter, via strand invasion, stabilizing the quadruplex structure formed by the genomic G-rich sequence, resulting in transcriptional inhibition. Strand invading oligonucleotides represent a new approach to specifically inhibit VEGF expression that avoids many of the problems which have plagued the therapeutic use of oligonucleotides. This is a novel approach to specific inhibition of gene expression.<br />Competing Interests: The authors have declared that no competing interests exist.
- Subjects :
- A549 Cells
Carcinoma, Non-Small-Cell Lung genetics
Carcinoma, Non-Small-Cell Lung metabolism
Drug Delivery Systems
Gene Expression Regulation, Neoplastic drug effects
Humans
Lung Neoplasms genetics
Lung Neoplasms metabolism
MAP Kinase Signaling System drug effects
MAP Kinase Signaling System genetics
Neoplasm Proteins genetics
Oligonucleotides genetics
Vascular Endothelial Growth Factor A genetics
Carcinoma, Non-Small-Cell Lung drug therapy
G-Quadruplexes
Lung Neoplasms drug therapy
Neoplasm Proteins biosynthesis
Oligonucleotides pharmacology
Promoter Regions, Genetic
Vascular Endothelial Growth Factor A biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 1932-6203
- Volume :
- 14
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- PloS one
- Publication Type :
- Academic Journal
- Accession number :
- 30682194
- Full Text :
- https://doi.org/10.1371/journal.pone.0211046