Phosphorothioate-modified CpG oligodeoxynucleotide (CpG ODN) induces apoptosis of human hepatocellular carcinoma cells independent of TLR9.
Toll-like receptors (TLRs) expressed on cancer cells are closely associated with tumor development. In this study, we investigated the biological functions of the TLR9 ligand, CpG oligodeoxynucleotide (CpG ODN), on TLR9 expressed in the cytoplasm of hepatocellular carcinoma (HCC) cells. In vitro, human HCC cell lines were transfected with phosphorothioate-modified oligodeoxynucleotides TLR9 agonist OND M362 and its negative control ODN M362 ctrl, which inhibited the proliferation of HCC cells by inducing apoptosis without altering the cell cycle. Interestingly, ODN M362 and ODN M362 Ctrl displayed a similar proapoptotic effect on HCC, possibly related to phosphorothioate modification of the structure of CpG ODN. Although both of them resulted in the upregulation of the TLR9 receptor, their effect on HCC apoptosis was independent of TLR9. They also upregulated inflammatory cytokines, but did not activate the NF-κB signaling pathway. Finally, the activities of ODN M362 and ODN M362 Ctrl were demonstrated in nude mice inoculated with HCC cells. These findings suggest that the phosphorothioate-modified TLR9 agonist ODN M362, and its control, elicit antitumor activity in HCC cells and may serve as a novel therapeutic target for HCC therapy.
Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua West Road, Jinan, 250012, China.
Yuyi
Y
Zhang
Ang
A
Lin
Cai
C
Zhang
Zhigang
Z
Tian
Jian
J
Zhang
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D018899:CpG Islands; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000819:agonists* / Q000096:biosynthesis / Q000235:genetics; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012334:RNA, Neoplasm / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D013047:Specific Pathogen-Free Organisms; D051217:Toll-Like Receptor 9 / Q000819:agonists* / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D016207:Cytokines; D009363:Neoplasm Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; C588272:ODN M362