Mitoxantrone and ametantrone induce interstrand cross-links in DNA of tumour cells

We show here that mitoxantrone and ametantrone induce interstrand DNA cross-links in HeLa S3cells. These cross-links were observed only in cellular system suggesting that metabolism of the drugs is a necessary step leading to DNA cross-linking. Biologically inactive analogue of mitoxantrone, compound NSC 321458, did not induce cross-links in DNA of tumour cells which suggests that DNA cross-linking is associated with the cytotoxic and anti-tumour activity of these compounds. © 2000 Cancer Research Campaig

129. Zaburzenia liczby kopii genów erbB-1 i erbB-2 i ich związek z danymi klinicznymi u leczonych operacyjnie chorych na niedrobnokomórkowego raka płuca

Szlak sygnałowy nabłonkowego czynnika wzrostu (ang. epidermal growth factor, EGF) i jego receptory (najważniejsze z nich to erbB-1 i erbB-2) odgrywają ważną rolę w patogenezie i progresji raka płuca. Kliniczne znaczenie nadekspresji tych receptorów pozostaje nadal przedmiotem kontrowersji a dotychczasowe badania przynosiły sprzeczne wyniki. Z uwagi na opracowane ostatnio leki o wybiórczym działaniu przeciwnowotworowym, działające poprzez powyższe receptory, poznanie rokowniczego znaczenia tych zaburzeń może odegrać ważną rolę w ustalaniu optymalnego sposobu leczenia. Celem pracy była ocena rokowniczego znaczenia anomalii średniej liczby kopii genów (ang. avarage gene copy numer, AGCN) u chorych na niedrobnokomórkowego raka płuca poddanych resekcji miąższu płucnego.Materiał i metodyDo badania włączono 112 chorych leczonych operacyjnie w latach 1996–1999. U 61 chorych (55%) rozpoznano postać raka płaskonabłonkowego, u 30 (27%) gruczolakoraka, u 10 (9%) raka wielokomórkowego i u 10 (9%) chorych postacie mieszane. Stopień zaawansowania nowotworu kształtował się następująco: I=54 (48%), II=11 (10%), III=40 (36%), IV=7 (6%). Materiał do analizy molekularnej stanowiło DNA izolowane ze świeżo mrożonych wycinków guza pobranych podczas zabiegu operacyjnego. AGCN określano za pomocą podwójnie różnicowej reakcji polimerazy i elektroforezy agarozowej.WynikiŚrednia wartość AGCN dla erbB-1 wynosiła 2,0 (zakres od 0,01 do 28,07), a dla erbB-2 1,34 (zakres od 0,11 do 9,9). Stwierdzono znamienną zależność pomiędzy AGCN dla obu genów. Nie stwierdzono znamiennego związku z jakimkolwiek głównym parametrem klinicznym. Do czasu przeprowadzenia analizy zmarło 73 chorych (65%). Po czasie obserwacji o medianie 5,1 roku nie stwierdzono wpływu AGCN na czas przeżycia (log-rank, P=0,9; 0,83; 0,8 odpowiednio dla erbB-1, erbB-2 i dla obu genów łącznie).WnioskiUzyskane wyniki wskazują na brak rokowniczego znaczenia AGCN erbB-1 i erbB-2 u chorych na raka płuca poddanych resekcji miąższu płucnego

Cellular uptake, cytotoxicity and DNA-binding studies of the novel imidazoacridinone antineoplastic agent C1311

C1311 is a novel therapeutic agent with potent activity against experimental colorectal cancer that has been selected for entry into clinical trial. The compound has previously been shown to have DNA-binding properties and to inhibit the catalytic activity of topoisomerase II. In this study, cellular uptake and mechanisms by which C1311 interacts with DNA and exerts cytotoxic effects in intact colon carcinoma cells were investigated. The HT29 colon cancer cell line was chosen to follow cellular distribution of C1311 over a time course of 24 h at drug concentrations that just inhibited cell proliferation by 50% or 100%. Nuclear uptake of C1311 and co-localization with lysosomal or mitochondrial dyes was examined by fluorescence microscopy and effects on these cellular compartments were determined by measurement of acid phosphatase levels, rhodamine 123 release or DNA-binding behaviour. The strength and mode of DNA binding was established by thermal melting stabilization, direct titration and viscometric studies of host duplex length. The onset of apoptosis was followed using a TUNEL assay and DNA-fragmentation to determine a causal relationship of cell death. Growth inhibition of HT29 cells by C1311 was concomitant with rapid drug accumulation in nuclei and in this context we showed that the compound binds to duplex DNA by intercalation, with likely A/T sequence-preferential binding. Drug uptake was also seen in lysosomes, leading to lysosomal rupture and a marked increase of acid phosphatase activity 8 h after exposure to C1311 concentrations that effect total growth inhibition. Moreover, at these concentrations lysosomal swelling and breakdown preceded apoptosis, which was not evident up to 24 h after exposure to drug. Thus, the lysosomotropic effect of C1311 appears to be a novel feature of this anticancer agent. As it is unlikely that C1311-induced DNA damage alone would be sufficient for cytotoxic activity, lysosomal rupture may be a critical component for therapeutic efficacy. © 1999 Cancer Research Campaig

Prisoners' attitudes towards cigarette smoking and smoking cessation: a questionnaire study in Poland

BACKGROUND: In the last decade Poland has successfully carried out effective anti-tobacco campaigns and introduced tobacco control legislation. This comprehensive strategy has focused on the general population and has led to a considerable decrease in tobacco consumption. Prisoners constitute a relatively small part of the entire Polish population and smoking habits in this group have been given little attention. The aim of the study was to assess the prevalence of cigarette smoking in Polish male prisoners, factors determining smoking in this group, prisoners' attitudes towards smoking cessation, and to evaluate prisoners' perception of different anti-tobacco measures. METHODS: An anonymous questionnaire including personal, demographic and smoking data was distributed among 944 male inmates. Of these, 907 men aged between 17 and 62 years (mean 32.3 years) met the inclusion criteria of the study. For the comparison of proportions, a chi-square test was used with continuity correction whenever appropriate. RESULTS: In the entire group, 81% of the subjects were smokers, 12% – ex-smokers, and 7% – never smokers. Current smokers had significantly lower education level than non-smokers (p < 0.0001) and ever-smokers more frequently abused other psychoactive substances than never smokers (p < 0.0001). Stress was reported as an important factor in prompting smoking (77%). Forty-nine percent of daily smokers were aware of the adverse health consequences of smoking. The majority of smokers (75%) had attempted to quit smoking in the past. Forty percent of smoking prisoners considered an award for abstaining from cigarettes as the best means to limit the prevalence of smoking in prisons. CONCLUSION: The prevalence of cigarette smoking among Polish prisoners is high. However, a majority of smokers attempt to quit, and they should be encouraged and supported. Efforts to reduce cigarette smoking in prisons need to take into consideration the specific factors influencing smoking habits in prisons

Detection of Adriamycin–DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations

Limited sensitivity of existing assays has prevented investigation of whether Adriamycin–DNA adducts are involved in the anti-tumour potential of Adriamycin. Previous detection has achieved a sensitivity of a few Adriamycin–DNA adducts/104 bp DNA, but has required the use of supra-clinical drug concentrations. This work sought to measure Adriamycin–DNA adducts at sub-micromolar doses using accelerator mass spectrometry (AMS), a technique with origins in geochemistry for radiocarbon dating. We have used conditions previously validated (by less sensitive decay counting) to extract [14C]Adriamycin–DNA adducts from cells and adapted the methodology to AMS detection. Here we show the first direct evidence of Adriamycin–DNA adducts at clinically-relevant Adriamycin concentrations. [14C]Adriamycin treatment (25 nM) resulted in 4.4 ± 1.0 adducts/107 bp (∼1300 adducts/cell) in MCF-7 breast cancer cells, representing the best sensitivity and precision reported to date for the covalent binding of Adriamycin to DNA. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin–DNA adduct detection and revealed adduct formation within an hour of drug treatment. This method has been shown to be highly reproducible for the measurement of Adriamycin–DNA adducts in tumour cells in culture and can now be applied to the detection of these adducts in human tissues

Amifostine reduces the seminiferous epithelium damage in doxorubicin-treated prepubertal rats without improving the fertility status

<p>Abstract</p> <p>Background</p> <p>Amifostine is an efficient cytoprotector against toxicity caused by some chemotherapeutic drugs. Doxorubicin, a potent anticancer anthracycline, is known to produce spermatogenic damage even in low doses. Although some studies have suggested that amifostine does not confer protection to doxorubicin-induced testicular damage, schedules and age of treatment have different approach depending on the protocol. Thus, we proposed to investigate the potential cytoprotective action of amifostine against the damage provoked by doxorubicin to prepubertal rat testes (30-day-old) by assessing some macro and microscopic morphometric parameters 15, 30 and 60 days after the treatment; for fertility evaluation, quantitative analyses of sperm parameters and reproductive competence in the adult phase were also carried out.</p> <p>Methods</p> <p>Thirty-day-old male rats were distributed into four groups: Doxorubicin (5 mg/kg), Amifostine (400 mg/kg), Amifostine/Doxorubicin (amifostine 15 minutes before doxorubicin) and Sham Control (0.9% saline solution). "Standard One Way Anova" parametric and "Anova on Ranks" non-parametric tests were applied according to the behavior of the obtained data; significant differences were considered when p < 0.05.</p> <p>Results</p> <p>The rats killed 30 and 60 days after doxorubicin treatment showed diminution of seminiferous epithelium height and reduction on the frequency of tubular sections containing at least one type of differentiated spermatogonia; reduction of sperm concentration and motility and an increase of sperm anomalous forms where observed in doxorubicin-treated animals. All these parameters were improved in the Amifostine/Doxorubicin group only when compared to Doxorubicin group. Such reduction, however, still remained below the values obtained from the Sham Control group. Nevertheless, the reproductive competence of doxorubicin-treated rats was not improved by amifostine pre-administration.</p> <p>Conclusions</p> <p>These results suggest that amifostine promotes a significant reduction of the doxorubicin long-term side effects on the seminiferous epithelium of prepubertal rats, which is reflected in the epidydimal fluid parameters in the adult phase. However, fertility status results suggest that such protection may not be effective against sperm DNA content damage. Further investigation of sperm DNA integrity must be carried out using amifostine and doxorubicin-treated experimental models.</p

Viscum album L. extracts in breast and gynaecological cancers: a systematic review of clinical and preclinical research

<p>Abstract</p> <p>Background</p> <p><it>Viscum album </it>L. extracts (VAE, European mistletoe) are a widely used medicinal plant extract in gynaecological and breast-cancer treatment.</p> <p>Methods</p> <p>Systematic review to evaluate clinical studies and preclinical research on the therapeutic effectiveness and biological effects of VAE on gynaecological and breast cancer. Search of databases, reference lists and expert consultations. Criteria-based assessment of methodological study quality.</p> <p>Results</p> <p>19 randomized (RCT), 16 non-randomized (non-RCT) controlled studies, and 11 single-arm cohort studies were identified that investigated VAE treatment of breast or gynaecological cancer. They included 2420, 6399 and 1130 patients respectively. 8 RCTs and 8 non-RCTs were embedded in the same large epidemiological cohort study. 9 RCTs and 13 non-RCTs assessed survival; 12 reported a statistically significant benefit, the others either a trend or no difference. 3 RCTs and 6 non-RCTs assessed tumour behaviour (remission or time to relapse); 3 reported statistically significant benefit, the others either a trend, no difference or mixed results. Quality of life (QoL) and tolerability of chemotherapy, radiotherapy or surgery was assessed in 15 RCTs and 9 non-RCTs. 21 reported a statistically significant positive result, the others either a trend, no difference, or mixed results. Methodological quality of the studies differed substantially; some had major limitations, especially RCTs on survival and tumour behaviour had very small sample sizes. Some recent studies, however, especially on QoL were reasonably well conducted. Single-arm cohort studies investigated tumour behaviour, QoL, pharmacokinetics and safety of VAE. Tumour remission was observed after high dosage and local application. VAE application was well tolerated. 34 animal experiments investigated VAE and isolated or recombinant compounds in various breast and gynaecological cancer models in mice and rats. VAE showed increase of survival and tumour remission especially in mice, while application in rats as well as application of VAE compounds had mixed results. <it>In vitro </it>VAE and its compounds have strong cytotoxic effects on cancer cells.</p> <p>Conclusion</p> <p>VAE shows some positive effects in breast and gynaecological cancer. More research into clinical efficacy is warranted.</p

Thermal and optical characterization of high power laser diodes

Semiconductor lasers have become one of the most ubiquitous classes of lasers due to their efficiency, ease of modulation, size, and other factors. As these devices are quite small and can reach impressive optical densities, waste heat dissipation becomes a key consideration in many applications. Thermally induced effects such as spectral shift, broadening, and inefficiency can drastically degrade device performance for a desired application. This study attempts to quantify and analyze the thermal effects in laser diodes through a two-part approach. First, modeling of the temperature profile throughout the laser package is used to gain insight into the heat propagation. The model agrees to within 0.6 degrees Celsius of the experimental values withing four seconds after laser turn-on. This simulation gives insights into the heat dissipation of the device and also highlights the importance of choosing proper materials for spreading heat from the laser. The second part of this study consists of a statistically designed run of experiments is used to gather multiple performance characteristics and statistically correlate the effect of input variables onto those characteristics. Data taken included temperature rise of the device, relative spectral power, and beam quality images. The resulting analysis provides a comprehensive picture of how the device responds to thermal perturbations and what the consequence of those responses are. Statistically determined parameters from the experiment, such as the wavelength dependence on coolant temperature, were found to agree to within 1\% of the manufacturer\u27s specifications