Chemosensitivity of mdr1 gene overexpressed multidrug resistant cancer cells to lidamycin / 药学学报

<p><b>AIM</b>To investigate the chemosensitivity to lidamycin (C-1027) in mdr1 gene overexpressing cancer cell lines established by drug induction and by gene-transfection.</p><p><b>METHODS</b>DNA was cloned by RT-PCR and then eukaryotic expressing recombinant plasmid pcDNA3. 1/mdrl was constructed. Using Lipofectamine 2000, a strain of stably transfected human hepatoma cancer cells, HepG2/mdrl, was obtained. The mdr1 mRNA level, P-glycoprotein (P-gp) level and the activity of P-gp to extrude drugs in cancer cells were determined by RT-PCR, immunofluorescence analysis and rhodamine 123 efflux assay. The chemosensitivity of cancer cells with low or high mdr1 expression to lidamycin and other antitumor drugs was tested by MTT assay.</p><p><b>RESULTS</b>The mdr1 mRNA and P-gp levels in KBv200, MCF-7/ADR, and stably transfected HepG2/mdr1 cells were much higher than that in respective parent KB, MCF-7 and HepG2 cells. The IC50 values of lidamycin for KBv200, MCF-7/ADR and HepG2/mdrl cells were (0.24 +/- 0.20) nmol x L(-1), (0.028 +/- 0.011) nmol x L(-1), and (0.020 +/- 0.011) nmol x L(-1), respectively. Compared with parental cells, the values of resistant fold for KBv200, MCF-7/ADR and HepG2/mdr1 cells to lidamycin were 6.8, 1.6 and 1.3 fold; to adriamycin were 37.2, 181.3 and 8.8 fold; to taxol were 336.8, 49.2 and 40.3 fold, respectively.</p><p><b>CONCLUSION</b>Lidamycin is highly active to multidrug resistant cancer cells. The chemosensitivity of those resistant cancer cells to lidamycin is approximately at the similar level as that of parent cancer cells.</p>

A study on biomarkers of styrene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the biomarkers of styrene and to provide theoretical basis for bio-monitoring of styrene.</p><p><b>METHODS</b>Urinary mandalic acid (MA), phenylglyoxalic acid (PGA) and mercapturic acid (MUA) of styrene were examined by high performance liquid chromatography (HPLC).</p><p><b>RESULTS</b>The correlation regression equations between exposure dose and MA, PGA and MUA level in morning urinary samples were: ŷ = 2.58x + 70.82; ŷ = 1.66x + 37.42; ŷ = 0.05x + 0.55 respectively. The correlation regression equations between exposure dose and MA, PGA and MUA level in post-shift urinary samples were: ŷ = 1.85x + 89.02; ŷ = 1.33x + 4.32; ŷ = 0.04x + 0.68 respectively. All showed close dose-response relationship.</p><p><b>CONCLUSIONS</b>The level of MA, PGA and MUA in morning or post-shift urinary samples may be used as bio-monitoring indexes of styrene.</p>