- 著者
- Mei Tsuchida Takumi Yokosawa Takuya Noguchi Tatsuya Shimada Mayuka Yamada Yuto Sekiguchi Yusuke Hirata Atsushi Matsuzawa
- 出版者
- The Japanese Society of Toxicology
- 雑誌
- The Journal of Toxicological Sciences (ISSN:03881350)
- 巻号頁・発行日
- vol.45, no.4, pp.219-226, 2020 (Released:2020-04-01)
- 参考文献数
- 47
- 被引用文献数
- 2 16
Tumor necrosis factor receptor-associated factor 2 (TRAF2) is an essential component of tumor necrosis factor-α (TNF-α) signaling that regulates nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways, and compelling evidence has demonstrated that TRAF2 suppresses TNF-α-induced cytotoxicity. On the other hand, it has been reported that oxidative stress-induced cytotoxicity is potentiated by TRAF2, indicating that TRAF2 both positively and negatively regulates stress-induced cytotoxicity in a context-specific manner. However, the causal role of TRAF2 in DNA damage response (DDR) remains to be explored. In this study, we assessed the function of TRAF2 in DDR induced by cisplatin, a representative DNA-damaging agent, and found that TRAF2 exerts pro-apoptotic activity through p53-dependent mechanisms at least in human fibrosarcoma cell line HT1080. TRAF2 deficient cells exhibit significant resistance to cell death induced by cisplatin, accompanied by the reduction of both p53 protein level and caspase-3 activation. Moreover, cisplatin-induced JNK activation was attenuated in TRAF2-deficient cells, and pharmacological inhibition of JNK signaling suppressed p53 stabilization. These results suggest that TRAF2 promotes p53-dependent apoptosis by activating the JNK signaling cascade in HT1080 cells. Thus, our data demonstrate a novel function of TRAF2 in cisplatin-induced DDR as a pro-apoptotic protein.
- 著者
- Yuto Sekiguchi Mayuka Yamada Takuya Noguchi Chise Noomote Mei Tsuchida Yuki Kudoh Yusuke Hirata Atsushi Matsuzawa
- 出版者
- The Japanese Society of Toxicology
- 雑誌
- The Journal of Toxicological Sciences (ISSN:03881350)
- 巻号頁・発行日
- vol.44, no.6, pp.435-440, 2019 (Released:2019-06-04)
- 参考文献数
- 24
- 被引用文献数
- 3 13
Fas/CD95 plays a pivotal role in T cell-mediated cytotoxicity. Accumulating evidence has suggested that resistance to Fas-mediated apoptosis contributes to the escape of cancer cells from immune destruction, and allows to undergo proliferation and outgrowth of cancer cells. In this study, we found that the anti-cancer drug gefitinib, a tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR), has an ability to enhance Fas-mediated cytotoxicity. In the presence of nontoxic concentrations of gefitinib, Fas-induced activation of caspase-8 and subsequent apoptosis was dramatically promoted, suggesting that gefitinib increases the sensitivity to Fas-mediated apoptosis. Interestingly, the effects of gefitinib were observed in EGFR or p53 knockout (KO) cells. These observations indicate that both EGFR and p53 are dispensable for the enhancement. On the other hand, gefitinib clearly downregulated heat shock protein 70 (HSP70) as previously reported. Considering that HSP70 contributes to protection of cells against Fas-mediated apoptosis, gefitinib may increase the sensitivity to Fas-mediated apoptosis by downregulating HSP70. Thus, our findings reveal novel properties of gefitinib, which may provide insight into the alternative therapeutic approaches of gefitinib for Fas-resistant tumors.
- 著者
- Mayuka Yamada Midori Suzuki Takuya Noguchi Takumi Yokosawa Yuto Sekiguchi Natsumi Mutoh Takashi Toyama Yusuke Hirata Gi-Wook Hwang Atsushi Matsuzawa
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- BPB Reports (ISSN:2434432X)
- 巻号頁・発行日
- vol.3, no.1, pp.16-21, 2020 (Released:2020-11-26)
- 参考文献数
- 27
- 被引用文献数
- 4 6
Both NF-E2-related factor 2 (Nrf2) and heat shock protein 70 (HSP70) contribute to cellular defense to various stresses, and have emerged as candidates of therapeutic targets to improve or prevent tissue damage. Cefotaxime (CTX), a third-generation cephalosporin antibiotic, is conceived as a safe drug largely free from side effects. CTX exhibits broad-spectrum antimicrobial activity, and thereby, is most commonly prescribed for the treatment of infectious diseases induced by Gram-positive or Gram-negative bacteria. In this study, we unexpectedly found the beneficial properties of CTX that upregulate both Nrf2 and HSP70 to the extent that stress-induced damage is ameliorated. Non-toxic levels of reactive oxygen species (ROS) induced by CTX activated the Nrf2 pathway without cytotoxicity, which in turn upregulated HSP70. Interestingly, the cytotoxicity of Fas/CD95 ligand (FasL), a cytotoxic cytokine that strongly induces apoptosis, was significantly ameliorated by pre-treatment with CTX, most likely because of the upregulation of Nrf2 and HSP70. Our results therefore show novel properties of CTX, which raise the possibility that CTX works as a non-toxic therapeutic agent for preventing and repairing tissue damage.