Anti-metastasis And Anti-tumor Activities Of Bi-aptamer For Triple Negative Breast Cancer Treatment

Triple negative breast cancer(TNBC)is the most aggressive and metastatic subtype of breast cancer and lack of targeted therapy strategy.Based on tumor markers of TNBC cells,rapid and effective therapeutic schedule for TNBC can be developed.Aptamers are highly structured DNA or RNA oligonucleotide chains that are screened from the systematic evolution of ligands by exponential enrichment(SELEX).Aptamer can be used as receptor agonists,inhibitors,nanotherapeutic vectors or imaging agents.The development of aptamers for the treatment and inhibition of metastasis of TNBC have important research significance.In this paper,the overexpressed CD44 receptor and nucleolin receptor on TNBC cells,as well as two receptor corresponding aptamers(TA1 and AS1411),were used to study the anti-metastasis and anti-tumor activity of TNBC.The following research results were achieved:1.The linker sequences were added to the tail of TA1 and AS1411 respectively that obtaining dual aptamer functional chains S1 and S2.And two control chains(S3 and S4)were designed to regulate targeting ability of AS1411 aptamer.A bi-aptamer system was constructed.When the aptamer targeted to TNBC receptors on cells,the two aptamers could be paired together by linker.And then the aptamer labeled with fluorophore caused the fluorescence signal change.In flow cytometry instrument and cell fluorescence imaging,TNBC cells were distinguished from other cells according to different fluorescence signals.2.The bi-aptamer binding on cells to induce receptor aggregation.The effects of cell motility,migration and invasion of TNBC,as well as the changes of epithelial-mesenchymal transformation related proteins were investigated.The bi-aptamer could realize the regulation of receptor function related to metastasis on TNBC cells,inhibit the metastasis ability of TNBC,and effectively resist the induced metastasis of TNBC by hyaluronic acid.3.Based on the double helix structure of AS1411 and control chain,the chemotherapy drug doxorubicin(S2’@DOX)was loaded to precise drug delivery on breast cancer.The uptake of DOX by cell was detected by fluorescence experiments,and it was found that the S2’@DOX drug loading system can effectively deliver drugs to breast cancer cells that overexpressed with nucleolin.In vitro cytotoxicity experiments showed that the killing of breast cancer cells by S2’@DOX was consistent with free DOX at the same concentration,but the toxicity of the drug to normal cells was greatly reduced.In this paper,a scheme that can regulate receptor function and target drug delivery through aptamers is prepared.It can effectively inhibit the metastasis of TNBC,and deliver drugs to cancer cells,thereby reducing the damage of drugs to normal cells.