• Title/Summary/Keyword: overexpression toxicity

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Studies on a Toxin/Antitoxin System in Streptococcus iniae (어류병원균 Streptococcus iniae의 toxin/antitoxin system에 대한 연구)

  • Yoon, Seongyong;Kim, Yeon Ha;Jeun, Moonjung;Seong, Minji;Yoo, Ah Young;Lee, Donghee;Moon, Ki Hwan;Kang, Ho Young
    • Journal of Life Science
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    • v.29 no.1
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    • pp.97-104
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    • 2019
  • Streptococcus iniae is a typical fish pathogen causing streptococcosis and it can also cause zoonotic infectious diseases. We studied S. iniae FP5228 isolated from infected olive flounder in Wando, Korea. In a study to find virulence factors in FP5228, we found that the number of live bacteria decreased dramatically in culture medium containing S. iniae FP5228 for more than 24 hr. This phenomenon was hypothesized to be related to Toxin ${\zeta}$ and Antitoxin ${\varepsilon}$ genes, components of the Toxin/ Antitoxin (TA) system on the 14 kb plasmid of FP5228. We used a protein overexpression system to identify it. The pBP1140 vector system was constructed to regulate the expression of Toxin ${\zeta}$ and Antitoxin ${\varepsilon}$ by IPTG and Arabinose. E. coli/pBP1140 strain grew slowly in early growth under toxin expression condition, and it was confirmed by microscopic observation that the strain became longer. S. iniae CK287, lacking a 14 kb plasmid of S. iniae FP5228 strain, was constructed. CK287 bacterial cells did not show rapid killing during culture, and the ability to produce biofilm was also decreased, and toxicity was weakened in cytotoxicity test and fish test. These results suggest that the TA system is involved in physiological regulation and expression of virulence factors in S. iniae FP5228.

20 (S)-ginsenoside Rh2 inhibits colorectal cancer cell growth by suppressing the Axl signaling pathway in vitro and in vivo

  • Zhang, Haibo;Yi, Jun-Koo;Huang, Hai;Park, Sijun;Kwon, Wookbong;Kim, Eungyung;Jang, Soyoung;Kim, Si-Yong;Choi, Seong-kyoon;Yoon, Duhak;Kim, Sung-Hyun;Liu, Kangdong;Dong, Zigang;Ryoo, Zae Young;Kim, Myoung Ok
    • Journal of Ginseng Research
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    • v.46 no.3
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    • pp.396-407
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    • 2022
  • Background: Colorectal cancer (CRC) has a high morbidity and mortality worldwide. 20 (S)-ginsenoside Rh2 (G-Rh2) is a natural compound extracted from ginseng, which exhibits anticancer effects in many cancer types. In this study, we demonstrated the effect and underlying molecular mechanism of G-Rh2 in CRC cells in vitro and in vivo. Methods: Cell proliferation, migration, invasion, apoptosis, cell cycle, and western blot assays were performed to evaluate the effect of G-Rh2 on CRC cells. In vitro pull-down assay was used to verify the interaction between G-Rh2 and Axl. Transfection and infection experiments were used to explore the function of Axl in CRC cells. CRC xenograft models were used to further investigate the effect of Axl knockdown and G-Rh2 on tumor growth in vivo. Results: G-Rh2 significantly inhibited proliferation, migration, and invasion, and induced apoptosis and G0/G1 phase cell cycle arrest in CRC cell lines. G-Rh2 directly binds to Axl and inhibits the Axl signaling pathway in CRC cells. Knockdown of Axl suppressed the growth, migration and invasion ability of CRC cells in vitro and xenograft tumor growth in vivo, whereas overexpression of Axl promoted the growth, migration, and invasion ability of CRC cells. Moreover, G-Rh2 significantly suppressed CRC xenograft tumor growth by inhibiting Axl signaling with no obvious toxicity to nude mice. Conclusion: Our results indicate that G-Rh2 exerts anticancer activity in vitro and in vivo by suppressing the Axl signaling pathway. G-Rh2 is a promising candidate for CRC prevention and treatment.