Cisplatin-DNA adduct formation in patients treated with cisplatin-based chemoradiation: lack of correlation between normal tissues and primary tumor

Contains fulltext : 69595.pdf (publisher's version ) (Closed access)PURPOSE: In this study, the formation of cisplatin-DNA adducts after concurrent cisplatin-radiation and the relationship between adduct-formation in primary tumor tissue and normal tissue were investigated. METHODS: Three intravenous cisplatin-regimens, given concurrently with radiation, were studied: daily low-dose (6 mg/m(2)) cisplatin, weekly 40 mg/m(2), three-weekly 100 mg/m(2). A (32)P-postlabeling technique was used to quantify adducts in normal tissue [white blood cells (WBC) and buccal cells] and tumor. RESULTS: Normal tissue samples for adduct determination were obtained from 63 patients and tumor biopsies from 23 of these patients. Linear relationships and high correlations were observed between the levels of two guanosine- and adenosine-guanosine-adducts in normal and tumor tissue. Adduct levels in tumors were two to five times higher than those in WBC (P<0.001). No significant correlations were found between adduct levels in normal tissues and primary tumor biopsies, nor between WBC and buccal cells. CONCLUSIONS: In concurrent chemoradiotherapy schedules, cisplatin adduct levels in tumors were significantly higher than in normal tissues (WBC). No evidence of a correlation was found between adduct levels in normal tissues and primary tumor biopsies. This lack of correlation may, to some extent, explain the inconsistencies in the literature regarding whether or not cisplatin-DNA adducts can be used as a predictive test in anticancer platinum therapy

De detectie van bis(tri-n-butyltin)oxide, hexachloorbenzeen en ozon op natural killer activiteit in de rattelong, gebruikmakend van een nieuw ontwikkelde methode

Dit rapport beschrijft de ontwikkeling van een methode om natural killer activiteit in de long te meten. Deze activiteit is van groot belang voor de weerstand in longweefsel tegen virale infecties en het ontstaan van neoplasma's. Met behulp van deze methoden werd aangetoond dat 2 stoffen, waarvan bekend is dat zij toxische effecten in de long induceren (O-3, HCB), en een, die een effect heeft op systematische NK-activiteit (TBTO) een effect op long NK-activiteit hadden. Vervolgonderzoek zal moeten aangeven of de test voorspellende waarde heeft ten aanzien van een verhoogde gevoeligheid voor virale infecties. In dit vervolgonderzoek zullen effecten van een aantal stoffen worden onderzocht met behulp van deze test.DGM/LHI

The 32P-postlabeling assay for DNA adducts

32P-postlabeling analysis is an ultrasensitive method for the detection and quantitation of carcinogen-DNA adducts. It consists of four principal steps: (i) enzymatic digestion of DNA to nucleoside 3'-monophosphates; (ii) enrichment of the adduct fraction of the DNA digest; (iii) 5'-labeling of the adducts by transfer of 32P-orthophosphate from [gamma-32P]ATP mediated by polynucleotide kinase (PNK); (iv) chromatographic or electrophoretic separation of the labeled adducts or modified nucleotides and quantitation by measurement of their radioactive decay. The assay requires only microgram quantities of DNA and is capable of detecting adducts at frequencies as low as 1 in 10(10) nt, making it applicable to the detection of events resulting from environmental exposures, or experiments using physiological concentrations of agents. It has a wide range of applications in human, animal and in vitro studies, and can be used for a wide variety of classes of compound and for the detection of adducts formed by complex mixtures. This protocol can be completed in 3 d