Down-regulation of lung resistance related protein by RNA interference targeting survivin induces the reversal of chemoresistances in hepatocellular carcinoma / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Both survivin and lung resistance related protein (LRP) are related to the chemoresistances in hepatocellular carcinoma (HCC). But the relationship between survivin and LRP is indefinite. The aim of this study was to investigate the effects of down-regulation of survivin on LRP expressions and the reversal of chemoresistances in HCC both in vitro and in vivo.</p><p><b>METHODS</b>The expressions of survivin were detected by RT-PCR and Western blotting in HCC cell line SMMC-7721 and SMMC-7721/ADM. The sensitivities of these two cell lines to ADM were evaluated by MTT assays. SiRNA which targeted survivin was transfected into SMMC-7721/ADM cells, then the sensitivity of SMMC-7721/ADM cells to ADM and the expressions of survivin and LRP were detected respectively. SMMC-7721/ADM cells were transplanted subcutaneously into nude mice to establish xenograft tumors. Antitumor activities of RNA interference (RNAi) targeting survivin, various doses of ADM and combination therapies were observed respectively. Possible toxicities were evaluated. LRP expression changes were tested. Student's t test was used for evaluating statistical significance.</p><p><b>RESULTS</b>The expressions of survivin in SMMC-7721/ADM cell line showed significant elevation compared to those in SMMC-7721 cell line (P < 0.05). Positive siRNA down-regulated the expressions of survivin significantly (P < 0.05). SiRNA targeting survivin could sensitize SMMC-7721/ADM cells to ADM and down-regulate the expressions of LRP significantly (P < 0.05). Growths of the tumors were significantly inhibited in positive siRNA group as compared with those in the control group from the 8th day (P < 0.05). Combination therapies caused significant tumor inhibitions compared with tumors of nude mice in the other three groups respectively (P < 0.05). No toxicities were found in nude mice treated by siRNA and combination therapies. The expressions of LRP were markedly reduced in tumors treated with siRNA targeting survivin (P < 0.05).</p><p><b>CONCLUSIONS</b>Down regulation of survivin gene by RNAi can increase chemosensitivity of HCC both in vitro and in vivo. The reversal of drug resistance may be reduced through the inhibitions of LRP.</p>

Expression of MDR1 and GST-pi in osteosarcoma and soft tissue sarcoma and their correlation with chemotherapy resistance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the expression of multidrug resistance gene 1 ( MDR1), glutathione-S-transferases-pi (GST-pi) in osteosarcoma and soft tissue sarcoma tissues from 34 patients and their correlation with chemotherapy resistance.</p><p><b>METHODS</b>MDR1 and GST-pi expressions were analyzed by real-time fluorescence quantitative polymerase chain reaction (FQ-PCR) and flow cytometry (FCM) at mRNA and protein levels, respectively. Chemotherapy sensitivity on adriamycin, cisplatinum, fluorouracil, mitomycin C, dacarbazine, vincristine, methotrexate in tumor tissues were detected by MTT assay.</p><p><b>RESULTS</b>The nonsensitive rates on adriamycin, cisplatinum, fluorouracil, mitomycin C, dacarbazine, vincristine, methotrexate in tumor tissues were 41.18%, 17.7%, 47.1%, 50.0%, 76.5%, 61.8% and 52.9%, respectively. The expression of P-glycoprotein (P-gp) and GST-pi in tumor tissues was 1.54 and 2.58 (relative fluorescence intensity). Chi2 analysis showed that there was a positive correlation between P-gp expression and drug resistance on ADM, GST-pi expression and resistance on ADM, DDP and MMC (P < 0.05). There was not seen obvious correlation between expression of MDR1, GST-pi and age, gender, pathological type, tumor size in osteosarcoma and soft tissue sarcoma patients (P > 0.05). The expression of GST-pi was increased in patients receiving preoperative chemotherapy. The rate of postoperative recurrence was higher in patients with higher GST-pi expression level than those with lower GST-pi expression level before operation (P < 0.05).</p><p><b>CONCLUSION</b>Individual differences exist in chemotherapy sensitivity and expression of MDR1 and GST-pi in osteosarcoma and soft tissue sarcomas patients. Chemotherapy can induce up-regulation of GST-pi protein expression. Primary high expression of GST-pi is the main mechanism of resistance of osteosarcoma and soft tissue sarcomas to chemotherapy and is related to poor prognosis.</p>

Role of dibromdulictol as a radlosensltlzer using two radiotherapy schedules for the management of brain secondaries

The present study analyzed 70 patients with brain secondaries from solid tumours referred to Radiotherapy and Oncology Unit, Faculty of Medicine, University of Alexandria between 1988 and 1990. Whole brain irradiation was the standard method of treatment using Co-60 teletherapy. Four treatment schedules were evaluated including SO GY/2 weeks without and with Dibromdulictol [DBD] [group I and II respectively], 30 GY/3 weeks without and [group III and IV respectively]. Good to fair tolerance was observed in 16/20 [80%], 22/15 [80%] 15/20 [75%] and 13/15 [80%] in the four treatment groups respectively, P>0.05. Performance status was not significantly improved following treatment in radiotherapy + DBD groups compared to radiotherapy alone, P>0.05. Furthermore the addition of DBD to radiotherapy was accompanied, with increased, incidence of toxicities especially haematological one9 yet the latter were tolerable and reversible. Intracranlal relapses were lower. In radiotherapy and DBD than those of radiotherapy alone, P> 0.05. On the other hand, no significant survival difference was observed among different treatment groups