CRISPR/Cas9-mediated overexpression of long non-coding RNA SRY-box transcription factor 21 antisense divergent transcript 1 regulates the proliferation of osteosarcoma by increasing the expression of mechanistic target of rapamycin kinase and Kruppel-like factor 4

Osteosarcoma, derived from primitive mesenchymal cells, is the most common primary solid malignant tumor of bone. The cause of osteosarcoma remains unclear. In recent years, the role of non-coding sequences in regulating protein expression in tumors has been paid more and more attention, especially long non-coding RNA (lncRNA). We speculate that SRY-box transcription factor 21 antisense divergent transcript 1 (SOX21-AS1) can regulate the expression of the mechanistic target of rapamycin kinase (mTOR) and Kruppel-like factor 4 (KLF4) through sponging hsa-mir-7-5p and hsa-mir-145-5p. We knocked lncRNA SOX21-AS1 into the genome of 143B cells through CRISPR/Cas9, then screened out a monoclonal cell line. Detect the transcription level and protein expression level of the above-mentioned related genes, and cell proliferation. Then, ginsenoside Rg3 was added to culture the cell line knocked into lncRNA SOX21-AS1, and the expression levels of lncRNA SOX21-AS1, hsa-mir-7-5p, hsa-mir-145-5p, mTOR, and KLF4 were detected by RT-qPCR and Western blot. Cell proliferation method detects cell viability, explores the molecular mechanism of lncRNA SOX21-AS1 in osteosarcoma, and checks whether it can be used as a potential drug target for the treatment of osteosarcoma. Our results demonstrate that the overexpression of lncRNA SOX21-AS1 up-regulates mTOR and KLF4 by sponging hsa-mir-7-5p and hsa-mir-145-5p, and ultimately regulates the proliferation of osteosarcoma. It is proved that ginsenoside Rg3 can inhibit the cell proliferation of osteosarcoma by reducing the expression level of lncRNA SOX21-AS1. It provides an alternative for the treatment of osteosarcoma in the future.