1. College of Biological and Food Engineering, Huaihua University, Huaihua, Hunan 418000, China.
2. Center for Reproduction and Health Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, Guangdong 518055, China.
3. College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan.
4. Department of Gynecology and Obstetrics, Southern Medical University, Guangzhou, Guangdong 510515, China.
#These authors contributed equally to this study.
Background: Placental-like chondroitin sulfate A (pl-CSA) is exclusively expressed in cancerous and placental tissues and is highly correlated with the degree of malignancy. However, the mechanism through which pl-CSA regulates tumorigenesis and metastasis in choriocarcinoma remains unclear.
Methods: Stable transfectants of the JEG3 choriocarcinoma cell line, including a negative control (NC) line and a cell line with knockout of the biosynthetic enzyme CS synthase-2 (ChSy-2) (ChSy-2-/-), were obtained using CRISPR/Cas9 systems and identified by immunofluorescence, flow cytometry, western blots and enzyme-linked immunosorbent assays (ELISAs). The proliferation, migration, invasion and colony formation of the cells were determined by a cell counting kit, scratch-wound assays, transwell assays and soft agar colony formation assays in vitro, respectively. The tumorigenesis and metastasis of choriocarcinoma were also investigated through two xenograft models in vivo.
Results: The ChSy-2 protein in the ChSy-2-/-group was below the detection threshold, which was accompanied a significant reduction in the pl-CSA level. Reducing pl-CSA through ChSy-2 knockout significantly inhibited cell proliferation, migration, invasion and colony formation in vitro and tumorigenesis and metastasis of choriocarcinoma, with deceases in tumor volume and metastatic foci and a high percent survival compared to the NC in vivo.
Conclusion: pl-CSA, as a necessary component of JEG-3 cells, was efficiently reduced through ChSy-2 knockout, which significantly inhibited the tumorigenesis and metastasis of choriocarcinoma. ChSy-2/pl-CSA could be alternative targets for tumor therapy.
Keywords: choriocarcinoma, ChSy-2/pl-CSA, tumorigenesis, molecular therapy