Dai-Wei Li

Publications of Dai-Wei Li

• Errata: Properties and Expression of a Multidrug Efflux Pump AcrAB-KocC from Klebsiella pneumoniae[Biol. Pharm. Bull. 31(4): 577-582 (2008)].

  Authors: Dai-Wei Li, Motoyasu Onishi, Takanori Kishino, Taira Matsuo, Wakano Ogawa, Teruo Kuroda, Tomofusa Tsuchiya

  Biological & pharmaceutical bulletin. 01/2011; 34(4):594.

• Properties and expression of a multidrug efflux pump AcrAB-KocC from Klebsiella pneumoniae.

  Authors: Dai-Wei Li, Motoyasu Onishi, Takanori Kishino, Taira Matsuo, Wakano Ogawa, Teruo Kuroda, Tomofusa Tsuchiya

  Biological & pharmaceutical bulletin. 05/2008; 31(4):577-82.

  We previously reported that we had cloned genes responsible for multidrug resistance from the chromosomal DNA of Klebsiella pneumoniae MGH78578 using a drug-hypersusceptible Escherichia coli strainWe previously reported that we had cloned genes responsible for multidrug resistance from the chromosomal DNA of Klebsiella pneumoniae MGH78578 using a drug-hypersusceptible Escherichia coli strain as a host. One of the recombinant plasmids pETV6 conferred resistance to host cells against a wide range of antimicrobial agents, dyes and detergents. It was revealed that this plasmid carried the acrBKp gene and a part of the acrAKp gene coding for a multidrug efflux pump belonging to the RND family. We cloned the whole acrAKpBKp operon of K. pneumoniae and characterized the pump. The AcrAB pump utilized TolC as an outer membrane component in cells of E. coli. Elevated energy-dependent efflux of ethidium was observed with cells possessing AcrAKp BKp-TolC. We cloned a gene coding for an ortholog of TolC from chromosomal DNA of K. pneumoniae, and designated it kocC. It seems that the AcrAKpBKp-KocC complex functions as a potent multidrug efflux pump in K. pneumoniae. We observed a higher level of expression of acrAKp in K. pneumoniae MGH78578, a multidrug resistant strain, compared with ATCC10031, a drug susceptible strain.

• Heat shock proteins play a crucial role in tumor-specific apoptosis by REIC/Dkk-3.

  Authors: Fernando Abarzua, Masakiyo Sakaguchi, Ryuta Tanimoto, Hiroyuki Sonegawa, Dai-Wei Li, Kohei Edamura, Tomoko Kobayashi, Masami Watanabe, Yuji Kashiwakura, Haruki Kaku, Takashi Saika, Keiichiro Nakamura, Yasutomo Nasu, Hiromi Kumon, Nam-Ho Huh

  International journal of molecular medicine. 08/2007; 20(1):37-43.

  We recently showed that overexpression of REIC/Dickkopf-3 (Dkk-3), a tumor suppressor gene, induced apoptosis in a tumor cell-specific manner. The aim of the present study was to determine theWe recently showed that overexpression of REIC/Dickkopf-3 (Dkk-3), a tumor suppressor gene, induced apoptosis in a tumor cell-specific manner. The aim of the present study was to determine the mechanisms underlying the selective induction of apoptosis. At first, we found a mouse renal carcinoma cell line, RENCA, to be extremely sensitive to an adenovirus carrying REIC/Dkk-3 (Ad-REIC), and we showed that activation of c-Jun N-terminal kinase (JNK) was a critical step in cell death, i.e. a process similar to that in human prostate and testicular cancer observed in our previous studies. Among the proteins interfering with the activation of JNK, heat shock protein (Hsp)70/72 was reduced in expression in RENCA cells compared with that in NIH3T3 cells. An Hsp70/72 inducer protected RENCA cells from Ad-REIC-induced apoptosis, while an Hsp70/72 inhibitor sensitized NIH3T3 cells for apoptosis induction. These results indicate that functionally active Hsp70/72 is a key factor in tumor cell-specific induction of apoptotic cell death and that analyses of the expression levels of Hsp70/72 may be essential in determining the significance of Ad-REIC-based gene therapy against human cancer.

• Involvement of deterioration in S100C/A11-mediated pathway in resistance of human squamous cancer cell lines to TGFbeta-induced growth suppression.

  Authors: Hiroyuki Sonegawa, Takamasa Nukui, Dai-Wei Li, Mikiro Takaishi, Masakiyo Sakaguchi, Nam-Ho Huh

  Journal of molecular medicine (Berlin, Germany). 08/2007; 85(7):753-62.

  Recently, we demonstrated that S100C/A11 comprises an essential pathway for growth suppression by TGFbeta in normal human keratinocytes. Nuclear transfer of S100C/A11 was a hallmark of the activationRecently, we demonstrated that S100C/A11 comprises an essential pathway for growth suppression by TGFbeta in normal human keratinocytes. Nuclear transfer of S100C/A11 was a hallmark of the activation of the process. In the present study, we examined the possible deterioration in the pathway in human squamous cancer cell lines, focusing on intracellular localization of S100C/A11 and its functional partners Smad3 and Smad4. All four human squamous cancer cell lines examined (A431, BSCC-93, DJM-1, and HSC-5) were resistant to growth suppression by TGFbeta. In BSCC-93, DJM-1, and HSC-5 cells exposed to TGFbeta, S100C/A11 was not transferred to the nuclei, and p21(WAF1) was not induced. Overexpression of nucleus-targeted S100C/A11 partially recovered induction of p21(WAF1) and p15(INK4B) and growth suppression by TGFbeta1 in these cells. These results indicate that the deterioration in the S100C/A11-mediated pathway conferred upon the cancer cell lines resistance to TGFbeta. In A431 cells, S100C/A11, Smad3, and Smad4 were simultaneously transferred to the nuclei, and p21(WAF1) was induced upon exposure to TGFbeta. We provide evidence to indicate that refractoriness of A431 cells to TGFbeta was probably because the amount of p21(WAF1) induced by TGFbeta was insufficient to counteract cyclin A, which is highly overexpressed in A431 cells. Thus, the newly found S100C/A11-mediated pathway is at least partly involved in conferring upon human squamous cell cancers resistant to TGFbeta-induced growth suppression, which is considered to play a critical role for the initiation and progression of many human cancers.

• Multidrug resistance in Klebsiella pneumoniae MGH78578 and cloning of genes responsible for the resistance.

  Authors: Wakano Ogawa, Dai-Wei Li, Ping Yu, Anowara Begum, Tohru Mizushima, Teruo Kuroda, Tomofusa Tsuchiya

  Biological & pharmaceutical bulletin. 09/2005; 28(8):1505-8.

  Klebsiella pneumoniae MGH78578, a clinical isolate, showed high level of resistance to many antimicrobial agents. We cloned genes responsible for drug resistance from chromosomal DNA of K. pneumoniaeKlebsiella pneumoniae MGH78578, a clinical isolate, showed high level of resistance to many antimicrobial agents. We cloned genes responsible for drug resistance from chromosomal DNA of K. pneumoniae MGH78578 by shotgun method using Escherichia coli KAM32, a drug hypersensitive strain, as host. We obtained 43 hybrid plasmids that made host cells resistant to several antimicrobial agents. We classified them into 17 groups based on growth properties in the presence of each one of 9 antimicrobial agents and on restriction patterns of each hybrid plasmid. Analysis of the cloned genes must be very useful for investigation of major parts of multidrug resistance systems including multidrug efflux pumps in K. pneumoniae MGH78578 in which genome sequence is available.