Transcriptional changes facilitate mitotic catastrophe in tumour cells that contain functional p53

Exposure of Jurkat T lymphocytes containing functional p53 to nanomolar concentrations of bisanthracycline WP631 resulted in arrest at the G₂/M checkpoint and transient senescence-like phenotype in the presence of DNA synthesis. The cells entered crisis, became polyploid, showed aberrant mitotic figures, and died through mitotic catastrophe. Cell death was accompanied by changes in the expression profile of various oncogenes and tumour suppressor genes including the down-regulation of p53. The changed expression was confirmed for some of these genes using semi-quantitative RT-PCR, and the decline in p53 protein levels was established. Our results suggest that WP631 induced changes in cell cycle control pathways leading to death of Jurkat T cells through mitotic catastrophe, which occurred in the absence of caspase-2 and caspase-3 activities, rather than apoptosis.     

Antitumor Activities of a Novel 9-Aminoanthracycline (SM-5887) against Mouse Experimental Tumors and Human Tumor Xenografts

The antitumor effects of SM-5887, a totally synthetic 9-aminoanthracycline derivative, were evaluated in six murinc experimental tumor systems (P38S, Ehrlich carcinoma, sarcoma 180, Lewis lung carcinoma, B16 melanoma and colon 38) and nine human tumor-nude mouse systems (one breast cancer, two lung cancers and six gastric cancers). Characteristically SM-5887 showed excellent antitumor activities, superior to adriamycin (ADR), against human tumor xenografts, although its activities against murine experimental tumors were almost equal to those of ADR. When the human tumors were implanted sc in female athymic mice (BALB/c, nu/nu ) and their volume reached 100- 300 mm³, SM-5887 and ADR were injected iv. All nine human tumors tested showed statistically significant responses to SM-5887, and 7 of them were strongly suppressed in their growth by SM-5887 so that minimum T/C values were less than 30% at the maximum tolerated dose (MTD, 25 mg/kg) with a single iv injection. Compared with ADR, SM-5887 was statistically more effective in five tumors (one breast, one lung and three gastric), equal in two tumors (two gastric), and less potent in two tumors (one lung and one gastric). In addition, the 10-day-interval repeated iv treatments with SM-5887 at the MTD (25 mg/kg) resulted in remarkably potent antitumor effects (including complete regression) against human gastric cancer, 4-1ST, implanted in nude mice without enhancement of toxic effects, SM-5887 was also effective against ip-inoculated P388 by oral administration as well as iv injection.     

Selective inhibition of rat and human cardiac guanylate cyclase in vitro by doxorubicin (adriamycin): possible link to anthracycline cardiotoxicity.

The cardiotoxicity of anthracycline antibiotic anti-tumor agents is well-described but the molecular basis of the cardiotoxicity is not understood. We examined the effect of doxorubicin (Adriamycin) on the activity of guanylate cyclase (E.C. 4.6.1.2), the enzyme catalyzing the production of guanosine 3′,5′-monophosphate, from rat heart, liver, lung, kidney, and spleen. Doxorubicin produced a decrease in cardiac guanylate cyclase activity over the concentration range 0.4 to 2 mm but was without effect, or slightly stimulated, guanylate cyclase from the other tissues. Daunorubicin (Daunomycin), a related, cardiotoxic anthracycline antibiotic also decreased cardiac guanylate cyclase activity over the concentration range 0.8 to 4 mm. Other antibiotic anti-tumor agents which are not cardiotoxic, including streptonigrin, porfiromycin, and mitomycin C did not decrease cardiac guanylate cyclase activity. Doxorubicin, 1 mm and 2 mm, and daunorubicin, 4 mm decreased cardiac guanylate cyclase approximately 50% in experiments utilizing guanylate cyclase prepared from human heart. The data suggests that some aspects of anthracycline cardiotoxicity may be related to altered cardiac guanylate cyclase activity.     

Cytotoxicity of Amrubicin, a Novel 9-Aminoanthracycline, and Its Active Metabolite Amrubicinol on Human Tumor Cells

Amrubicin, a completely synthetic 9-aminoanthracycline derivative, was previously shown to have potent antitumor activities against various human tumor xenografts. In this study, the in vitro activities of amrubicin and its major metabolite, amrubicinol, were examined using 17 human tumor cell lines. Amrubicinol was 5 to 54 times more potent than amrubicin, and as potent as doxorubicin, in inhibiting the growth of the cells following 3-day continuous drug exposure. Amrubicinol closely resembled doxorubicin in its profile of activities on the 17 human tumor cell lines. Cells were incubated with the drugs for 1 h, and the intracellular drug concentration and cell growth inhibition after 3 days were determined. Amrubicinol attained similar intracellular concentrations at lower medium concentrations compared to amrubicin, and the intracellular concentration of amrubicinol necessary to produce 50% cell growth inhibition was 3 to 8 times lower than that of amrubicin in 4 cell lines tested. Amrubicinol has a higher activity level inside the cells than does amrubicin. When cells were incubated with amrubicin for 5 h, a substantial amount of amrubicinol, more than 9% of that of amrubicin, was found in cells in 4 of the 8 cell lines tested. Amrubicinol may contribute to the in vitro growth-inhibitory effect of amrubicin on these cells. The results suggest that amrubicinol plays an important role in the in vivo antitumor effect of amrubicin as an active metabolite.     

Radiation injury to the heart

For the RTOG Consensus Conference on Late Effects of Cancer Treatment we summarize the clinical manifestations of cardiac complications appearing months to years following incidental irradiation of the heart during treatment of thoracic neoplasms. The most common effects present as pericardial disease, however, it is becoming more clear that precocious or accelerated coronary artery disease is an important late effect, especially in patients treated with radiation before the age of 21 years. To the extent it is known, the pathophysiology of the various syndromes is described and the extensive literature on dose, volume, and fractionation factors is reviewed. Based upon our current understanding of late cardiac effects, a clinical grading system has been developed and is published elsewhere in this issue.     

Comparative serum protein binding of anthracycline derivatives

 The binding of doxorubicin, iododoxorubicin, daunorubicin, epirubicin, pirarubicin, zorubicin, aclarubicin, and mitoxantrone to 600 μM human serum albumin and 50 μM alpha₁-acid glycoprotein was studied by ultrafiltration at 37°C and pH 7.4. Anthracycline concentrations (total and free) were determined by high-performance liquid chromatography (HPLC) with fluorometric detection. Binding to albumin (600 μM) varied from 61% (daunorubicin) to 94% (iododoxorubicin). The binding to alpha₁-acid glycoprotein (50 μM) was more variable, ranging from 31% (epirubicin) to 64% (zorubicin), and was essentially related to the hydrophobicity of the derivatives. Simulations showed that the total serum binding varied over a broad range from 71% (doxorubicin) to 96% (iododoxorubicin). Received: 8 October 1995 / Accepted: 20 March 1996     

Pharmacology of N,N-di(n-butyl)adriamycin-14-valerate in the rat

 Lipophilic N-alkylanthracyclines such as AD 198 (N-benzyladriamycin-14-valerate) or AD 201 [N,N-di-(n-propyl)adriamycin-14-valerate], which exert their cytotoxicity through mechanisms which are not yet fully defined, possess inherent abilities to circumvent multidrug resistance in vitro and in vivo, possibly through alterations in normal intracellular drug trafficking. As part of structure-activity studies with this class of agent, we have now examined the pharmacology of AD 202 [N,N-di(n-butyl)adriamycin-14-valerate], another analog possessing superior antitumor activity to doxorubicin in vivo and an ability to circumvent multidrug resistance in vitro. Following the administration of AD 202 (20 mg/kg, i.v.) to anesthetized rats, rapid drug distribution (T_1/2 5 min) was followed by more gradual elimination (T_1/2 3.6 h). Plasma clearance of AD 202 (224±63.6 ml/min per kg) and steady state volume of distribution (25.7±11.1 l/kg) were indicative of extensive tissue sequestration and/or a large degree of extra-hepatic metabolism. The parent drug predominated in plasma until 20 min, thereafter N,N-di(n-butyl)adriamycin became the principal circulating anthracycline. The systemic exposure to this biotransformation product (area under the plasma concentration-time curve from time zero to 480 min AUC_0-480 28 1672 ng ⋅ min/ml) was >tenfold higher than for the other detected plasma products (N-butyladriamycin-14-valerate, N-butyladriamycin, and three unidentified fluorescent signals; P1-3). Total urinary elimination over 8 h was limited (1.9% of dose), occurring predominantly as N,N-di(n-butyl)adriamycin (1.2% of dose), N-butyladriamycin (0.4% of dose), and their corresponding 13-carbinol metabolites (<0.1% of dose each). Low levels of adriamycin (ADR), aglycones and two unidentified products were also seen. Parental AD 202 was found in urine only up to 1 h. By contrast, hepatic elimination of parent drug was seen, albeit at low levels, through 8 h. Excretion by this route (22% of dose) occurred principally as N-butyladriamycin (8% of dose), N-butyladriamycinol (2.1% of dose) with lower levels of N,N-di(n-butyl)adriamycin (1.6% of dose), N,N-di(n-butyl)adriamycin (0.8% of dose), and aglycones (4.3% of dose, combined). Other products included ADR (1.1% of dose) and two unidentified signals (3.4% of dose, combined). The relatively poor mass balance in these studies is attributed to prolonged intracellular retention (elimination T_1/2 24.2 h) of N,N-di(n-butyl)adriamycin. Thus, in common with other N-alkylanthracyclines, the pharmacology of AD 202 is complex but its therapeutic properties clearly are not derived from an ADR prodrug effect. Significant differences continue to be noted as to the metabolic fate of congeners of this class of anthracycline analogs. Received: 19 September 1994/Accepted: 27 June 1995     

蒽环类药物早期所致右心系统形态学改变的研究

目的 蒽环类药物(ATC)对左右心功能均有损伤.本研究旨在应用超声心动图综合评价淋巴瘤患者经ATC化疗后右心系统亚临床功能的改变.方法 74例采用ATC治疗的淋巴瘤患者分别于化疗前及化疗2、4、6周期后行常规经胸二维超声心动图检查,获得右心房(RA)及右心室(RV)舒张末面积(EDA)、收缩末面积(ESA)和RV舒张末容积(EDV)、收缩末容积(ESV)及RV射血分数(EF);应用组织多普勒显像(TDI)获得三尖瓣环收缩期峰值速度和舒张早、晚期峰值速度;应用二维斑点追踪显像(2DSTE)技术分析右心室游离壁收缩期峰值应变及峰值应变率.结果 与化疗前相比,淋巴瘤患者化疗2、4周期后所有参数变化差异均无统计学意义(P＞0.05).化疗6周期后,应用TDI及2DSTE所得的各项参数变化差异仍均无统计学意义(P＞0.05);而RAEDA((6.6±1.9)cm2 vs(7.7±2.4)cm2)、RAESA((8.8±2.5) cm2 vs(10.8 ±2.8) cm2)、RVEDA((14.1±3.4) cm2 vs (16.2±3.7) cm2)、RVESA((7.9±1.9) cm2 vs (9.0±2.2) cm2)在化疗6周期后显著增大,其差异均有统计学意义(F=4.574,P=0.004;F=7.515,P=0.000;F=4.955,P=0.002;F=4.228,P=0.006);与此同时,RVEDV((29.8±10.5) ml vs(37.0±12.7) ml)、RVESV((12.7±4.4) ml vs (15.0±5.2) ml)明显增大,RVEF((59.4±5.8)％vs(56.4±5.8)％)显著下降,但仍维持在正常范围内,其差异均有统计学意义(F=5.168,P=0.002;F=2.829,P=0.039;F=3.961,P=0.009).化疗期间左心室射血分数(LVEF)变化差异无统计学意义(P＞0.05).结论 超声心动图可用于早期无创评估ATC所致有心系统亚临床功能损害.ATC致右心系统损伤首先表现为形态学改变;此外,RVEF有望成为评估ATC所致右心功能损伤的有价值指标.     

HER2 expression and efficacy of preoperative paclitaxel/FAC chemotherapy in breast cancer

Purpose We examined the correlation between HER2 expression and pathologic complete response (pCR) to paclitaxel/FAC (T/FAC) preoperative chemotherapy in breast cancer. Patients and Methods Retrospective analysis of data including 534 patients treated with preoperative T/FAC was performed. Gene expression results were available from two datasets of 132 and 286 patients, and were used to examine the co-expression of HER2 and topoisomerase II α (TOP2A) and microtubule associated protein tau (MAP-Tau). Results Of the 534 patients, 105 (20%) had HER2-overexpressing breast cancer. The pCR rates were 33% and 15% for patients with HER2+ and HER2- tumors (P < 0.001). The 5-year relapse-free survival rates were 94% and 70% in HER2+ tumors with and without pCR (P = 0.009). HER2 overexpression (odds ratio 2.3, 95%CI: 1.3–3.9, P = 0.004), estrogen receptor (ER) status, grade and weekly schedule of paclitaxel were each significantly and independently associated with pCR in multivariate analysis. When patients were stratified by ER status, the pCR rates were 50% for HER2+/ER−, 30% for HER2−/ER−, 19% for HER2+/ER+, and 6% for HER2−/ER+ tumors. HER2 overexpression was associated with lower expression of MAP-tau (P = 0.001 and P < 0.001) and higher expression of TOP2A mRNAs (P = 0.048 and P = 0.001) in patients with ER+ disease. ER− cancers had low MAP-tau expression regardless of HER-status. Conclusion HER2 overexpression is associated with higher rate of pCR to preoperative T/FAC chemotherapy regardless of ER status. HER2 overexpression also correlates with increased TOP2A and decreased MAP-tau expression in ER-positive cancers.