Cisplatin selects for stem-like cells in osteosarcoma by activating Notch signaling.
Notch signaling regulates normal stem cells and is also thought to regulate cancer stem cells (CSCs). Recent data indicate that Notch signaling plays a role in the development and progression of osteosarcoma, however the regulation of Notch in chemo-resistant stem-like cells has not yet been fully elucidated. In this study we generated cisplatin-resistant osteosarcoma cells by treating them with sub-lethal dose of cisplatin, sufficient to induce DNA damage responses. Cisplatin-resistant osteosarcoma cells exhibited lower proliferation, enhanced spheroid formation and more mesenchymal characteristics than cisplatin-sensitive cells, were enriched for Stro-1+/CD117+ cells and showed increased expression of stem cell-related genes. A similar effect was observed in vivo, and in addition in vivo tumorigenicity was enhanced during serial transplantation. Using several publicly available datasets, we identified that Notch expression was closely associated with osteosarcoma stem cells and chemotherapy resistance. We confirmed that cisplatin-induced enrichment of osteosarcoma stem cells was mediated through Notch signaling in vitro, and immunohistochemistry showed that cleaved Notch1 (NICD1) positive cells were significantly increased in a relapsed xenograft which had received cisplatin treatment. Furthermore, pretreatment with a γ-secretase inhibitor (GSI) to prevent Notch signalling inhibited cisplatin-enriched osteosarcoma stem cell activity in vitro, including Stro-1+/CD117+ double positive cells and spheroid formation capacity. The Notch inhibitor DAPT also prevented tumor recurrence in resistant xenograft tumors. Overall, our results show that cisplatin induces the enrichment of osteosarcoma stem-like cells through Notch signaling, and targeted inactivation of Notch may be useful for the elimination of CSCs and overcoming drug resistance.
Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Ling
L
Yu
Department of Orthopedic Oncology, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University Cancer Hospital & Institute, Beijing, China.
Zhengfu
Z
Fan
Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Shuo
S
Fang
Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Jian
J
Yang
Department of Orthopedic Oncology, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University Cancer Hospital & Institute, Beijing, China.
Tian
T
Gao
Breast Cancer Now Research Unit, Institute of Cancer Sciences, University of Manchester, Manchester, UK.
Bruno M
BM
Simões
Breast Cancer Now Research Unit, Institute of Cancer Sciences, University of Manchester, Manchester, UK.
Rachel
R
Eyre
Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Weichun
W
Guo
Breast Cancer Now Research Unit, Institute of Cancer Sciences, University of Manchester, Manchester, UK.
Robert B
RB
Clarke
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D012516:Osteosarcoma / Q000188:drug therapy* / Q000473:pathology; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D051880:Receptors, Notch; D002945:Cisplatin
Notch signaling pathway; cancer stem-like cells; chemo-resistance; osteosarcoma