Although the overall survival rate and prognosis of breast cancer patients has improved in recent years, metastasis is still the leading cause of mortality in breast cancer patients. Emerging evidence has shown that ncRNAs, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in particular, play crucial roles in various types of cancer through regulating coding gene expression and epigenetic signatures. Increased LINC02273 promoted breast cancer metastasis in vitro and in vivo. This study revealed the molecular mechanism of lncRNA driving breast cancer metastasis through epigenetic increase of AGR2 transcription. Targeting LINC02273 with ASOs showed potential in mitigating breast cancer metastasis, which has important significance for the development of ASO drugs for the treatment of metastatic breast cancer.
Recently, antisense oligonucleotide (ASO) drugs have gained increasing attention with their ability to target diverse RNAs, which has been validated both in vitro and in vivo. To explore the possibility of whether LINC02273 could be interfered by ASOs, three antisense oligonucleotides (ASOs) specifically targeting LINC02273 and one negative control targeting no known sequence in the human genome were designed for the study (Fig. 1a). LINC02273 mRNA expression was significantly inhibited by all three ASOs in MDA-MB-231, LM2, and BT549 cells (Fig. 1b). Accordingly, AGR2 expression was dramatically decreased when LINC02273 was suppressed (Fig. 1c).
This study further developed LINC02273-targeting ASO-1/ASO-2 and control ASO-NC with modifications optimized for in vivo study. Free uptake assays showed dose-dependent inhibition of LINC02273 in LM2 cells by ASO-1 and ASO-2 compared to NC (Fig. 1d). An orthotopic xenograft tumor model was used to determine the therapeutic efficacy of LINC02273 ASO treatment. Wild type LM2 cells were inoculated into mammary fat pads of NOD/SCID mice (Fig. 1e). After 2 weeks, mice were randomly assigned into three groups (ASO-1, ASO-2, and ASO-NC) and given respective ASO treatment by tail vein injection twice a week. Compared to ASO-NC, tumor growth was significantly decreased in the ASO-1 and ASO-2 groups (Fig. 1f). More prominently, significant reduction of lung metastasis was observed by bioluminescent imaging, which was further confirmed by H&E staining (Fig. 1g). Moreover, This study confirmed that the expression of LINC02273 and AGR2 mRNA levels were decreased in tumors tissues treated with ASO-1 and ASO-2, compared to the ASO-NC group (Fig. 1h). Collectively, this data demonstrated that LINC02273 played critical role in promoting breast cancer metastasis and targeting LINC02273 with ASOs might serve as an effective therapeutic approach to mitigate breast metastasis.
Synbio Technologies has established production workshops that meet the quality management requirements of ISO 9001 and ISO 13485, with a standard production process and excellent synthesis & purification technologies. Our synthetic antisense oligonucleotides strictly comply with QC testing standards. HPLC purity detection is used to ensure the high quality output of all our antisense oligonucleotide products.