化疗增敏剂影响 P-糖蛋白依赖多药耐药性肿瘤细胞~(99)Tc~m-MIBI 摄取的实验研究(英文)

目的观察化疔增敏剂对多药耐药性(Multi-drug resistance,MDR)肿瘤细胞 P-糖蛋白(P-glycoprotein,P-gp)的影响及伴随~(99)Tc~m-MI-BI 摄取动力学的变化,以建立用~(99)Tc~m-MIBI 来评价化疗增敏剂效果的方法。方法 MDR 人乳腺癌细胞 MCF-7/Adr 37℃培养。(1)实验组和对照组细胞培养基中分别加入化疗增敏剂维拉帕米(10 μmol/L)和等体积培养液 DMEM。~(99)Tc~m-MIBI 与细胞共同孵育2 h 后收集细胞,测定放射性活度和 P-gp 表达水平。(2)维拉帕米(10 μmol/L)加入细胞培养基中,与细胞孵育若干时间后~(99)Tc~m-MIBI 加入细胞培养基中,与细胞一起培养2 h 后收集细胞。测定放射性活度和P-gp 表达水平。结果 (1)维拉帕米作用2h 后,细胞摄取~(99)Tc~m-MIBI 较对照组显著增加(t=2.33,P<0.05),但 P-gp 表达水平差异无显著性(P>0.05)。(2)肿瘤细胞摄取~(99)Tc~m-MIBI 随维拉帕米作用时间的延长而增加,各时间点 UR 差异有显著性(F=58.2,P<0.05),并且,VRP 作用时间在80 min 内时,肿瘤细胞摄取~(99)Tc~m-MIBI 与 P-gp 的表达水平无相关性(r=0.16,P>0.05),VRP 作用时间大于8 h时,肿瘤细胞摄取~(99)Tc~m-MIBI 与 P-gp 的表达水平呈负相关(r=-0.73,P<0.01)。结论化疗增敏剂能够影响 P-gp 过度表达所致 MDR 肿瘤细胞对~(99)Tc~m-MIBI 的摄取。     

Discovery of Novel Small Molecule Mer Kinase Inhibitors for the Treatment of Pediatric Acute Lymphoblastic Leukemia

Ectopic Mer expression promotes pro-survival signaling and contributes to leukemogenesis and chemoresistance in childhood acute lymphoblastic leukemia (ALL). Consequently, Mer kinase inhibitors may promote leukemic cell death and further act as chemosensitizers increasing efficacy and reducing toxicities of current ALL regimens. We have applied a structure-based design approach to discover novel small molecule Mer kinase inhibitors. Several pyrazolopyrimidine derivatives effectively inhibit Mer kinase activity at sub-nanomolar concentrations. Furthermore, the lead compound shows a promising selectivity profile against a panel of 72 kinases and has excellent pharmacokinetic properties. We also describe the crystal structure of the complex between the lead compound and Mer, opening new opportunities for further optimization and new template design.     

Sensitizing effects of aradio－ and chemo－sensitizer，metronidazol amino acidum natrium（CMNa）

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诱导性一氧化氮抑制剂对鼻咽癌CNE-2细胞株作用的探讨

目的 观察诱导性一氧化氮合酶(iNOS)抑制剂S-甲基异硫脲(SMT)是否对鼻咽癌细胞株CNE-2有抑制细胞增殖的能力和促进凋亡的能力,探讨SMT对顺铂(DDP)的抗CNE-2细胞作用是否存在增敏效应及其分子机制.方法 选用鼻咽癌细胞株CNE-2作为研究对象,以A549作为对照,R.T-PCR测试CNE-2是否表达iNOS.用不同浓度的SMT、DDP和二者联合干预CNE-2细胞后,MTT试验及集落形成实验观察其对细胞活力的影响.Hoechst33258染色观察细胞凋亡的形态学变化.流式细胞仪检测细胞凋亡的水平.硝酸还原酶法测NO的含量.结果 以iNOS高表达的肺癌细胞株AS49为阳性对照,CNE-2细胞证实为iNOS阳性表达.SMT能以浓度依赖性的方式有效地抑制CNE-2细胞的增殖.0.5μmol/mL的SMT与6μg/mL的DDP共同干预CNE-2细胞,较之单用SMT或DDP抑制CNE-2细胞的凋亡形态学改变明显,凋亡小体以及核固缩现象增多,早期凋亡率增多(P＜0.05).0.5μ moi/mL的SMT与6μg/mL的DDP共同干预CNE-2细胞,与正常组相比,两组NO含量的差异有显著性(P＜0.05).结论 SMT能够有效地和浓度依赖性地抑制CNE-2细胞的增殖.SMT对DDP的抗CNE-2细胞作用具有化疗增敏效应,其机制可能与NO含量有关,但具体增敏机制还有待进一步研究.     

The synergistic therapeutic effect of cisplatin with Human papillomavirus E6/E7 short interfering RNA on cervical cancer cell lines in vitro and in vivo

Human papillomavirus (HPV) types 16 and 18 are the major etiologic factors in the development of cervical epithelial neoplasia. Our study was designed to validate antiviral short interfering RNA (siRNA) targeting the E6 and E7 oncogenes as a potential chemosensitizer of cisplatin (cis-diaminedichloroplatinum II; CDDP) in cervical carcinoma. Specifically, the therapeutic efficacy of combination of CDDP and E6/E7-specific siRNA was assessed in an in vivo cervical cancer xenograft models. The combination of CDDP and E6/E7-specific siRNA had greater efficacy than the combination of CDDP and E6-specific siRNA especially in terms of inducing cellular senescence. Through in vitro and in vivo experiments, the mechanism of synergy between these two treatments was revealed, demonstrating that the combination of E6/E7-specific siRNA and CDDP therapy was significantly superior to either modality alone. In vitro, long-term exposure of HeLa cells to the combination of CDDP and E6/E7-specific siRNA induced apoptosis and cellular senescence. In vivo, E6/E7-specific siRNA potentiated the antitumor efficacy of CDDP via induction of apoptosis, senescence and antiangiogenesis. Our results suggest that E6/E7-specific siRNA may be an effective sensitizer of CDDP chemotherapy in cervical cancer.     

Suramin as a Chemosensitizer: Oral Pharmacokinetics in Rats

Purpose. The purpose of this study was to determine if the 10-50 M plasma concentrations of suramin required to produce chemosensitization could be achieved by oral administration. Methods. Rats were given an oral dose of 100, 300, or 500 mg/kg unlabeled suramin by oral gavage. Rats receiving the 300 mg/kg oral dose of suramin also received a concomitant intravenous bolus injection of 50 Ci/kg of [³H]suramin, administered 57 min after the oral dose. The intravenous data were used to calculate the clearance. Serial plasma samples were collected over 24-336 h. Plasma concentration-time profiles were analyzed using noncompartmental and compartmental methods. The pharmacokinetic parameters derived for the 300 mg/kg oral and 50 Ci/kg intravenous doses were used to calculate the bioavailability and AUC at the three oral dose levels. Results. Plasma concentrations declined biexponentially following intravenous administration, with a distribution half-life of 2 h and an estimated terminal half-life of 276 h. Suramin absorption following oral gavage was variable and incomplete with mean maximal plasma concentrations of 9.04, 72.6, and 64.4 g/ml at doses of 100, 300, and 500 mg/kg, respectively. Seven of 15 rats exhibited two peak plasma concentrations at 1 h and 3 to 12 h, suggesting the existence of multiple absorption sites and/or enterohepatic circulation. Oral bioavailability, calculated using the clearance of the intravenous tracer dose, was <3% at all three dose levels. Conclusions. While plasma concentrations resulting from the 300 and 500 mg/kg oral doses of suramin were in the concentration range required to produce chemosensitization, the low bioavailability limits the usefulness of oral administration.     

Using ^99mTc-MIBI to Evaluate the Effects of Chemosensitizer on P-glycoprotein in Multidrug-resistant Carcinoma Cells

Objective: To establish a method to evaluate the effects of chemosensitizer on P-glycoprotein using ^99mTc-MIBI, and observe the changes of ^99mTc-MIBI uptake kinetics and P-glycoprotein levels after using verapamil in MDR human breast cells MCF-7/Adr. Methods: MDR breast carcinoma cells, MCF-7/Adr, were incubated and different protocols were performed. Protocol I: a chemosensitizer, verapamil (10 µmol/L), was added into cell culture medium, while in control group, the same volume of DMEM was given. Cells were harvested after 2 h incubation with ^99mTc-MIBI. Protocol II: Verapamil (10 µmol/L) was added into cell culture medium and incubated for 20 min, 40 min, 60 min, 80 min, 8 h, 24 h, 48 h and 72 h respectively. Cells were harvested after 2 h incubation with ^99mTc-MIBI. The radioactivity of the cells was measured and P-glycoprotein expression levels were determined with immunohistochemical stain. Results: Protocol I: After 2h incubation with verapamil the cellular uptake of ^99mTc-MIBI was remarkably higher than control group (t=2.33, P<0.05), but there was no difference in P-glycoprotein expression levels between two groups (P<0.05). Protocol II: In verapamil group, ^99mTc-MIBI uptake was increased with incubation time prolonging (F=58.2, P<0.05). When verapamil incubation time surpassed 8 h the ^99mTc-MIBI uptake negatively correlated to the P-glycoprotein expression levels (r=-0.73, P<0.01). However, when incubation time was less than 80 min, there was no correlation between ^99mTc-MIBI accumulation and P-glycoprotein levels (r=0.16, P>0.05). Conclusion: ^99mTc-MIBI may be used to evaluate the qualitative as well as quantitative change of P-glycoprotein expression levels induced by the chemosensitizer, verapamil.     

Pharmacokinetics of the multidrug-resistance-converting drug dexniguldipine and its pyridine metabolite M-1 in the plasma,tumor, and renal tissue of tumor-bearing Wag / Rij rats

The pharmacokinetics of oral dexniguldipine, a new multidrug-resistance-modifying agent under clinical evaluation, and its pyridine metabolite M-1 were determined in plasma, tumor, and renal tissue in Wag/Rij rats bearing a multidrug-resistant CC531 colon adenocarcinoma tumor under the renal capsule. The pharmacokinetics were studied in four experiments. After a single administration of dexniguldipine (30 mg/kg), tumors and kidneys were collected after 5 (experiment 1), 24 (experiment 2), and 48 h (experiment 3). In the fourth experiment, dexniguldipine was given once daily for 3 consecutive days at a dose of 30 mg/kg. In all experiments, plasma samples were collected at regular intervals. The concentrations of dexniguldipine and M-1 could be determined in plasma in most of the rats at up to 32 h after drug administration. The area under the curve (AUC) of dexniguldipine and M-1 varied by a factor of 2–6 in the four experiments. High tumor-tissue concentrations of dexniguldipine were observed. The concentrations were highest in the multiple-dose experiment (2014 ± 1005 ng/g tissue). High degrees of correlation (>0.8) were established between the concen-trations of dexniguldipine measured in plasma and tumor as well as renal tissue. Overall, tumor-tissue concentrations of M-1 comprised one-third of the dexniguldipine concentrations measured. Received: 7 January 1997 / Accepted: 1 June 1997     

甲基莲心碱对Saos-2细胞体外增敏作用的研究

目的探讨甲基莲心碱(Neferine ,Nef)对骨肉瘤细胞(Saos-2 cells)的体外化疗增敏作用.方法以人骨肉瘤细胞株(Saos-2 cells)为研究对象,MTT法测定药物的细胞生长抑制率,流式细胞仪(Flow Cytometry , FCM)检测细胞凋亡.结果 Nef(5,10μmol·L-1)分别为与阿霉素(ADM),5-氟尿嘧啶(5-Fu),顺铂(CDDP),鬼臼乙叉苷(VP16)合用,可增加它对Saos-2细胞的生长抑制率,q＞1.Nef(10μmol·L-1)可增强不同浓度ADM诱导Saos-2细胞凋亡.结论 Nef 对Saos-2细胞有化疗增敏作用.