Depletion of R270C Mutant p53 in Osteosarcoma Attenuates Cell Growth but Does Not Prevent Invasion and Metastasis In Vivo
Takatsune Shimizu,
Eiji Sugihara,
Hideyuki Takeshima,
Hiroyuki Nobusue,
Rui Yamaguchi,
Sayaka Yamaguchi-Iwai,
Yumi Fukuchi,
Toshikazu Ushijima,
Akihiro Muto,
Hideyuki Saya
Affiliations
Takatsune Shimizu
Department of Pathophysiology, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Eiji Sugihara
Open Facility Center, Research Promotion Headquarters, Fujita Health University, Toyoake 470-1192, Japan
Hideyuki Takeshima
Department of Epigenomics, Life Science Tokyo Advanced Research Center, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Hiroyuki Nobusue
Division of Gene Regulation, Cancer Center, Research Promotion Headquarters, Fujita Health University, Toyoake 470-1192, Japan
Rui Yamaguchi
Division of Cancer Systems Biology, Aichi Cancer Center Research Institute, Nagoya 464-8681, Japan
Sayaka Yamaguchi-Iwai
Department of Pathophysiology, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Yumi Fukuchi
Department of Pathophysiology, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Toshikazu Ushijima
Department of Epigenomics, Life Science Tokyo Advanced Research Center, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Akihiro Muto
Department of Pathophysiology, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Hideyuki Saya
Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
Novel therapeutic targets are needed to better treat osteosarcoma, which is the most common bone malignancy. We previously developed mouse osteosarcoma cells, designated AX (accelerated bone formation) cells from bone marrow stromal cells. AX cells harbor both wild-type and mutant forms of p53 (R270C in the DNA-binding domain, which is equivalent to human R273C). In this study, we showed that mutant p53 did not suppress the transcriptional activation function of wild-type p53 in AX cells. Notably, AXT cells, which are cells derived from tumors originating from AX cells, lost wild-type p53 expression, were devoid of the intact transcription activation function, and were resistant to doxorubicin. ChIP-seq analyses revealed that this mutant form of p53 bound to chromatin in the vicinity of the transcription start sites of various genes but exhibited a different binding profile from wild-type p53. The knockout of mutant p53 in AX and AXT cells by CRISPR–Cas9 attenuated tumor growth but did not affect the invasion of these cells. In addition, depletion of mutant p53 did not prevent metastasis in vivo. Therefore, the therapeutic potency targeting R270C (equivalent to human R273C) mutant p53 is limited in osteosarcoma. However, considering the heterogeneous nature of osteosarcoma, it is important to further evaluate the biological and clinical significance of mutant p53 in various cases.
