异汉防己碱增强阿霉素诱导乳腺癌细胞凋亡的实验研究

目的:探讨异汉防己碱增强阿霉素诱导耐阿霉素乳腺癌细胞系MCF-7/DOX凋亡的效应和机制。方法:采用MTT法检测异汉防己碱、阿霉素及两者联合对MCF-7/DOX细胞增殖的抑制作用,用流式细胞术定量分析MCF-7/DOX细胞的凋亡率,用Westem blot技术检测Bax及Bcl-2表达。结果:异汉防己碱可增强阿霉素对MCF-7/DOX细胞增殖的抑制作用,并可诱导细胞凋亡;异汉防己碱联合阿霉素可上调Bax表达,降低Bcl-2表达。结论:异汉防己碱联合阿霉素是通过上调Bax/Bcl-2比值而增强阿霉素诱导癌细胞凋亡的作用。     

In vivo measurement of myocardial oxidative metabolism and blood flow does not show changes in cancer patients undergoing doxorubicin therapy

Purpose: The aim was to investigate in patients receiving doxorubicin whether any alteration in myocardial oxidative metabolism or blood flow as assessed by positron emission tomography (PET) could be observed either after the first dose of the drug, or during its chronic administration. Methods: Six female non-heart-failure cancer patients treated with doxorubicin were included in a longitudinal study. Resting radionuclide cineangiography and PET scanning with carbon-11 acetate were performed the day before the initiation of doxorubicin treatment at a dosage of 50 mg/m² every 3 weeks, and 3 weeks after the cumulative administration of 300 mg/m² (chronic toxicity). In addition, PET was performed 24 h after the first administration of doxorubicin (evaluation of acute toxicity). Myocardial oxidative metabolism and blood flow were assessed by PET (acute and chronic toxicity), and left ventricular ejection fraction was measured by radionuclide angiography (chronic toxicity). Results: Using PET for both acute and chronic toxicity evaluations, no significant effect of doxorubicin was observed either on the flux through the tricarboxylic acid (TCA) cycle or on myocardial blood flow. However, systolic left ventricular function showed a small but significant impairment after the administration of 300 mg/m² of doxorubicin. Conclusions: Other hypotheses should be explored to better explain the predominant mechanisms of the cardiotoxicity of anthracyclines in humans. Received: 18 August 1999 / Accepted: 3 December 1999     

Interaction of dexrazoxane with red blood cells and hemoglobin alters pharmacokinetics of doxorubicin

Purpose: The mechanism of the cardioprotective action of dexrazoxane against doxorubicin cardiotoxicity is not fully understood. It has been suggested that its hydrolysis product, ICRF-198, chelates and removes free iron and iron associated with doxorubicin-iron complex and, therefore, prevents the formation of free radical, lipid peroxidation and cardiotoxicity. Dexrazoxane is also known to inhibit topoisomerase II, to prevent the inactivation of cytochrome c oxidase by Fe³⁺-doxorubicin and to increase the levels of transferrin receptor (trf-rec) mRNA and cellular iron uptake. This sequestration of iron and its effect on cellular iron homeostasis may also contribute to its protective effect against doxorubicin cardiotoxicity. The present project was designed to investigate the interaction of dexrazoxane with hemoglobin and red blood cells and the subsequent effect on the pharmacokinetics and toxicodynamics of doxorubicin. Methods: In an in vitro investigation the binding of doxorubicin (0.5–25 μg/ml) to red blood cells, erythrocyte ghosts and hemoglobin in the presence of dexrazoxane was evaluated. In an in vivo study female Sprague Dawley rats were pretreated with 100 mg/kg of dexrazoxane by intravenous injection 1 h before the injection of ¹⁴C-doxorubicin (specific activity 0.4 μCi/mg, 10 mg/kg). The time-course of doxorubicin associated with blood cells and plasma was evaluated with simultaneous characterization of doxorubicin and its metabolites in the bile and urine. The serum concentration of endothelin was measured as a biomarker of cardiotoxicity in separate groups of animals. Results: The in vitro data indicated that dexrazoxane inhibited the binding of DOX to red blood cells in a concentration-dependent manner. At 1 μg/ml it reduced the binding of doxorubicin to red blood cells by about 30% and at 100 μg/ml by about 60%. It had no effect on the association of doxorubicin with erythrocyte ghosts. The investigation of binding of doxorubicin to hemoglobin revealed the existence of two distinct binding sites and dexrazoxane reduced the association constant of doxorubicin with the low-affinity and high-capacity class of binding sites significantly. The pharmacokinetic analysis showed that pretreatment with dexrazoxane (100 mg/kg) reduced the area under plasma concentration-time curve of doxorubicin, its mean residence time and plasma clearance significantly. Similar reductions were also shown with the pharmacokinetic analysis of doxorubicin associated with blood cells. The biliary and urinary elimination of unchanged doxorubicin increased significantly. The pretreatment reduced the serum concentration of endothelin from about 20 ng/ml to about 12 ng/ml. The per cent of this reduction was proportional to the reduction in the AUC of blood cells. Conclusion: The cardioprotective effect of dexrazoxane is due, in part, to its interaction with hemoglobin and red blood cells and this interaction modifies the pharmacokinetics of DOX. Received: 29 July 1999 / Accepted: 11 February 2000     

低能超声对人肺癌细胞的体外杀伤作用

目的 探讨低能超声对人肺癌细胞的影响。方法 用低能量连续波超声处理小细胞肺癌细胞系ＳＭ、腺癌细胞系Ａ２及人肺纤维母细胞ＦＢ,用胎盘蓝染料排斥试验及克隆存活试验判定效果,结果 低能量（０．８Ｗ／ｃｍ＾２）超声３分钟分各种人肺癌细胞及人肺纤维母细胞有杀伤作用（Ｐ〈０．０５）,１０分钟可杀死全部细胞（Ｐ〈０．００１）,细胞浓度越高,杀伤作用越低,超声１０分钟后含细胞悬液的试管内温度未见显著上升,声强０．８Ｗ／ｃｍ＾２的超声使阿霉对肺癌细胞ＳＭ的杀伤作用增加１００倍（Ｐ〈０．００１）,结论 低能连续波超声可杀伤肺癌细胞,并能显著增加阿霉素对肺癌细胞的细胞毒性。     

Cytofluorescence localization of adriamycin in the nervous system

Summary By a fluorescence-microscopic technique, the distribution of the antineoplastic glycoside adriamycin (doxorubicin) was studied in the peripheral nervous system (PNS) of normal adult mice after i.v. injection. Doses comparable to those used in patients for treatment of malignant diseases were used.The orange-red fluorescence of the drug was observed in dorsal root ganglia, in the trigeminal ganglia, and in the superior cervical sympathetic ganglia where it was preferentially accumulated in the nuclei of satellite cells. This nuclear labeling was a very quick process which occurred in the superior cervical ganglion within 15 s after the injection. Adriamycin-fluorescent nuclei were also observed in the suprarenal medulla.Fluorescent nuclei were present within the pre- and postganglionic sympathetic nerve trunks close to the superior cervical ganglion but not in the endoneurium of the trigeminal and the sciatic nerves or in the spinal nerve roots. In such structures labeled cells appeared in the connective tissue sheaths covering the nerves and the roots. No adriamycin-induced fluorescence was detected in the myenteric plexus of the intestine.Our study thus shows that i. v. injected adriamycin is distributed preferentially within areas of the PNS where the blood vessels are known to be highly permeable.Supported by grants from the Swedish Medical Research Council Project 12X-03020     

Radiopharmaceutical model using99mTc-MIBI to evaluate amifostine protection against doxorubicin cardiotoxicity in rats

The aim of our study was to use an in vivo radiopharmaceutical model to investigate the cytoprotective effect of amifostine against doxorubicin-induced cardiotoxicity. Male Wistar rats were randomly divided into four groups (n = 6): 1) Saline (control); 2) Doxorubicin (DOX; 10 mg/ kg(-l) intraperitoneally); 3) Amifostine (AMI; 200 mg/kg(-1) intraperitoneally); 4) Doxorubicin plus amifostine (DOX + AMI). Amifostine was injected 30 minutes before doxorubicin in Group 4. 99mTc-MIBI, 20 MBq/0.2 ml(-1), was injected through the tail vein 72 hours after the drug administration. Rats were killed and samples of myocardium were removed by dissection 60 minutes after the injection of radiopharmaceutical. Radioactivity in each organ sample was counted using a Cd(Te) detector equipped with RAD 501 single-channel analyzer. The percent radioactivity was expressed as a percentage of the injected dose per gram of tissue (%ID/g(-1)). The %ID/g(-1) activity was calculated by dividing the activity in each sample by the total activity injected and mass of each organ. 99mTc-MIBI uptake as %ID/g(-1) was 1.194 +/- 0.502 and 0.980 +/- 0.199 in the control and AMI groups, respectively. Doxorubicin administration resulted in a significant increase in %ID/ g(-1) (3.285 +/- 0.839) (p < 0.05). Amifostine administration 30 minutes before doxorubicin injection resulted a significant decrease in %ID/g(-1) (2.160 +/- 0.791) (p < 0.05) compared with doxorubicin alone. The results showed that amifostine significantly attenuated doxorubicin-induced cardiotoxicity.     

A trend of improved survival of childhood hepatoblastoma treated with cisplatin and doxorubicin in Taiwanese children

Hepatoblastoma is the second most common childhood malignant hepatic tumor in Taiwan. Its prognosis used to be poor. We reviewed our cases in this decade to see if there has been any improvement of survival in our patients with hepatoblastoma. From 1988 to 2000, 19 patients with hepatoblastoma in this institution were included in the study. These patients clinical manifestations, laboratory and image studies, histological findings, treatment modalities and prognostic significance were analyzed. The mean age at diagnosis was 13.5 months, ranging from 0 to 4 years old (male:female =11:8). Abdominal distension was the most common symptom, and hepatomegaly was the most common physical finding. Laboratory abnormalities included elevated alpha-fetoprotein, thrombocytosis and abnormal liver function profiles. Treatment modalities included primary surgery with postoperative chemotherapy in three, chemotherapy only in four and preoperative chemotherapy plus surgery with or without postoperative chemotherapy in nine patients. The overall 2-year survival rate is 38.6%. The significant prognostic factors include patients compliance, resectability and chemotherapy protocol. The introduction of a new chemotherapy protocol designed by the International Society of Pediatric Oncology Study (SIOPEL) in 1994 improved the 2-year survival rate from 12.5 to 58.4% (P=0.01). In conclusion, the improved chemotherapy protocol enhances the survival rate of hepatoblastoma in Taiwanese children.     

Hsp10 and Hsp60 modulate Bcl-2 family and mitochondria apoptosis signaling induced by doxorubicin in cardiac muscle cells

The development of doxorubicin cardiomyopathy involves apoptosis of cardiac muscle cells. This study was carried out to define the roles of two heat-shock proteins, Hsp10 and Hsp60, on doxorubicin-induced apoptosis in primary cardiomyocytes. Doxorubicin induces apoptosis of cardiomyocytes by activating mitochondria apoptosis signaling. Transducing cardiomyocytes with Hsp10 or Hsp60 with adenoviral vector suppressed the occurrence of apoptosis in the doxorubicin-treated cardiomyocytes. Overexpression of Hsp10 and Hsp60 increased the abundance of the anti-apoptotic Bcl-xl and Bcl-2, and reduced the protein content of the pro-apoptotic Bax. Hsp60 overexpression also significantly reduced doxorubicin induction of Bad, whereas overexpression of Hsp10 did not alter the expression of Bad in the doxorubicin-treated cells. Overexpression of Hsp10 and Hsp60, respectively, stabilized mitochondrial cross-membrane potential, inhibited Caspase 3, and suppressed PARP. These findings indicate that overexpression of Hsp10 and Hsp60 differentially modulated Bcl-2 family and in turn attenuate doxorubicin-induced cardiac muscle death. The effects of Hsp10 and Hsp60 on Bcl-2 family could not be explained by the abundance of Bcl-2 family mRNA levels. Hsp60 interacted with Bcl-xl and Bax in the cardiomyocytes in vivo. The effect of Hsp10 and Hsp60 on the abundance of Bcl-xl could not be blocked by cycloheximide. Moreover, Hsp10 and Hsp60 inhibited ubiquitination of Bcl-xl. These findings suggest that Hsp10 and Hsp60 modulated post-translational modification of Bcl-xl. Antisense Hsp60 reduced the abundance of endogenous Hsp60 in cardiomyocytes and amplified the cytotoxicity of doxorubicin. These data provide a novel link between Hsp10/Hsp60 and cardiac protection in doxorubicin cardiomyopathy.     

Doxorubicin cardiotoxicity: Prevention of congestive heart failure with serial cardiac function monitoring with equilibrium radionuclide angiocardiography in the current era

BACKGROUND: Congestive heart failure (CHF) is among the most serious toxicities of doxorubicin, a potent cancer chemotherapeutic agent. Serial left ventricular ejection fraction (LVEF) monitoring during doxorubicin therapy for preventing CHF was proposed over 20 years ago. The current utility and cost-effectiveness of this approach in the present era are not known. METHODS AND RESULTS: Clinical and follow-up data of 265 patients with cancer (age, 53 +/- 14 years; 76% women) undergoing doxorubicin chemotherapy with serial equilibrium radionuclide angiocardiography (ERNA) monitoring (> or =2 studies) were analyzed retrospectively. Patients with a normal baseline LVEF (> or =50%) and a 10% or greater point fall in LVEF to a final value of less than 50% during doxorubicin therapy were considered "at risk" for CHF (n = 41). Over 679 +/- 426 days of follow-up, 7 patients (2.6%) had CHF develop and 90 (34%) died (all cancer-related deaths, with none due to CHF). A comparison of "at-risk" (n = 41 [15%]) and "low-risk" (n = 224 [85%]) groups showed a higher incidence of CHF (12% vs 0.9%, P <.0001), lower baseline LVEF (58% +/- 8% vs 64% +/- 8%, P <.0001), lower value for the lowest LVEF (42% +/- 8% vs 57% +/- 7%, P <.0001), and higher rate of cancer-related deaths (59% vs 29%, P =.0003) in the former despite similar cumulative doxorubicin dose (304 +/- 124 mg/m(2) vs 284 +/- 110 mg/m(2), P = not significant). There were no differences in age, gender, cancer type, and co-morbidity. Cost analysis showed the overall cost of ERNA studies to be lower than the 1-year cost of caring for additional cases of CHF that would potentially be prevented by routine LVEF monitoring. CONCLUSIONS: An incipient fall in LVEF detected on serial ERNA during doxorubicin therapy provides an appropriate and cost-effective approach for predicting and preventing impending CHF. Use of this approach was associated with a low incidence of CHF (2.6%) and no CHF-related mortality in this study.