Cisplatin is a classical Pt-based anticancer drug that is widely used for the treatment of a broad spectrum of tumors. Its cytotoxicity is mediated mainly through interactions with DNA and inhibition of DNA synthesis and replication by formation of bifunctional interstrand and intrastrand cross links. Despite its success, the clinical usefulness of cisplatin is limited by its severe side eff ects such as dose-dependent nephrotoxicity, nausea and vomiting, ototoxicity, neurotoxicity, and myelosuppression. While there has been some success in lowering the toxicity of platinum drugs (carboplatin) and limited success in overcoming acquired cisplatin resistance (oxaliplatin) there has been little success in developing drugs that show activity in cancer cell lines that have a natural resistance to cisplatin and carboplatin. The need for alternatives to cisplatin has consequently inspired further work towards the development of novel platinum-based drugs with improved and or complementary properties. Some strategies have been applied during synthesis of new platinum drugs, such as the use of diff erent ligands (pikoplatin or satraplatin), in order to reduce side eff ects or increase the cytotoxicity potential of the drug. Another strategy is the synthesis of dinuclear or trinuclear platinum complexes (BBR3464 and berenil complexes of platinium(II)) which may decrease the action of the cellular repair machinery by forming different types of complex-DNA adducts.
PL
Istotną grupą leków przeciwnowotworowych są koordynacyjne związki platyny. Cisplatyna jest najstarszym przedstawicielem leków przeciwnowotworowych zawierających w swej strukturze platynę. Jej cytotoksyczność wynika przede wszystkim z kowalencyjnego wiązania do DNA, co w konsekwencji prowadzi do hamowania syntezy i replikacji DNA poprzez formowanie wewnątrz- i międzyniciowych wiązań krzyżowych. Przeciwwskazaniem do jej stosowania jest wysoka toksyczność leku, która powoduje występowanie licznych działań niepożądanych, takich jak wymioty, neuro- i nefrotoksyczność, ototoksyczność czy supresja szpiku kostnego zależna od dawki. Leki drugiej generacji, takie jak karboplatyna i oksaplatyna w ograniczonym stopniu zmniejszyły toksyczność i nabytą odporność niektórych nowotworów na pochodne platyny. Potrzeba posiadania leku o działaniu analogicznym do cisplatyny, jednak wywołującego mniej działań niepożądanych i wykazującego szersze spektrum działania, powoduje stały rozwój prac nad nowymi przeciwnowotworowymi kompleksami platyny. Zmianę właściwości biologicznych można osiągnąć modyfi kując otoczenie koordynacyjne w kompleksach platyny. Wprowadzenie grupy 2-metylopirydyny w pikoplatynie czy też obecność cykloheksyloaminy w satraplatynie doprowadziło do otrzymania związków o wysokiej aktywności w stosunku do nowotworów cisplatynoopornych. Inną strategią jest synteza dwurdzeniowych i trzyrdzeniowych kompleksów platyny, takich jak BBR3464 i berenilowe kompleksy platyny (II). Zakłada się, że wielordzeniowe kompleksy platyny wiążące się w odmienny sposób niż cisplatyna z DNA będą posiadały szerokie spektrum aktywności przeciwnowotworowej przy niskiej toksyczności.
A molecular mechanics and molecular dynamics approach was used to examine the structure of complexes formed between the d(CGCGAATTCGCG)2 duplex and netropsin, distamycin, and four carbocyclic analogues of netropsin and distamycin (1-4). The resulting structures of the ligand-DNA model complexes and their energetics were examined. It is predicted that the compounds 1-4 should have a decreased affinity for the minor groove of AT-rich regions in comparison to netropsin and distamycin. From the energetic analysis it appears that van der Waals and electrostatic interactions are more important than specific hydrogen bonds in stabilizing the ligand-duplex complexes. We predict that compounds 1 and 2 are effectively isohelical with the DNA minor groove. The superior DNA-binding afforded by 1 and 2 in comparison to 3 and 4 results from their more effective penetration into the minor groove and smaller perturbation of molecular structure upon complex formation.
Pentamidine despite its rather high toxicity, is currently in clinical use. For development of new drugs of this type it is important to know the mechanism of their action. Two new amidines (I and II) and 4',6-diamidino-2-phenylindole (DAPI) were found in preliminary experiments to inhibit protein synthesis in vitro in the cell-free rat liver system. The three compounds differed in the precise mode of action. The inhibitory effect of I on the activity of the eukaryotic elongation factor eEF-2 and ribosomes seems to suggest that the binding site of eEF-2 on the ribosome was blocked by this compound. eEF-2 has been identified as the primary target of II and eEF-1 as the primary target of DAPI in the system studied.
A series of carbocyclic analogues of netropsin were synthesized and evaluated for their capacity to inhibit human topoisomerases I and II in vitro. The compounds are oligopeptides containing 1,4-di- and 1,2,5-trisubstituted benzene rings and unsubstituted N-terminal NH2 groups. Compounds 4-7 consist of two netropsin-like units linked by aliphatic (tetra- and hexamethylene) chains. In the topoisomerase I and II assay, the relaxation of pBR322 plasmid was inhibited by compounds 4-7 at 100 μM concentration.
A pilot study on relationships of selected molecular factors (c-myc oncogene average gene copy numbers (AGCN); serum CEA and CA 15.3 antigen levels; tumor cells' DNA values), to the ex vivo chemosensitivity of primary female human breast cancer in a modified adenosine triphosphate cell viability chemosensitivity assay (ATP-CVA), was performed. Four drug combinations were tested. A group of 75 cases of female primary breast cancer was assessed. Numerous correlations were found among molecular factors tested but none, with the exception of tumor grading, of these reflected ex vivo chemosensitivity of tumors tested. The results suggest that the parameters tested may not be important factors related to adjuvant chemoresponsiveness of primary human breast cancer to tested drug combinations.
A pilot study on relationships of selected molecular factors [erbB-1, erbB-2, erbB-3, and c-myc oncogene average gene copy numbers (AGCN); steroid receptors and pS2 gene expression; tumor cells' DNA values] to the ex vivo chemosensitivity of ovarian cancer in a modified adenosine triphosphate cell viability chemosensitivity assay (ATP-CVA), was performed. Despite the relatively small number of patients, numerous correlations among the factors tested were found. Nevertheless, only c-myc gene dosage positively affected ex vivo chemosensitivity of tumors tested.
Among possible causes of chronic hepatitis in adolescents most common are infections, autoimmune disorders and metabolic diseases. Thus, diagnostic procedures should be multidirectional. This study reports diagnosis and treatment difficulties in an 18-year-old male patient with hereditary hemochromatosis (HH), ulcerative colitis (UC), chronic hepatitis B (CHB) and Gilbert syndrome. The presented case illustrates problems in diagnostics related to the presence of numerous disease conditions in one patient. It should be taken into consideration that these diseases coexisting in one patient can mutually affect their symptoms creating specific diagnostic difficulties.
Objective: To assess the prevalence of UGT1A1*28 and UGT1A1*60 polymorphisms of UGT1A1 gene and their association with hyperbilirubinemia. Study design: The study was performed at a single centre - at the Department of Obstetrics of the Medical University of Gdansk in Poland. DNA was isolated from Guthrie cards of 171 infants. Only full term newborns (gestational age 38-42 weeks) were included in the study. Fluorescent molecular probes were used for UGT1A1 promoter variation analysis. The presence of UGT1A1*28 polymorphism was detected with a dual-probe system, and UGT1A1*60 with a SimpleProbe™. Result: Homozygous UGT1A1*28 and UGT1A1*60 genotypes were detected in 14.6% and 20.5% of the newborns, respectively. Homozygous (G/G) genotypes of UGT1A1*60 polymorphism were found in all of the UGT1A1*28 (i.e. (TA)7/(TA)7) homozygotes. More than 80% (55/66) of the children with "wild" type UGT1A1*28 genotype (where no polymorphism was detected) (i.e. (TA)6/(TA)6) carried the "wild" (T/T) genotype of UGT1A1*60 as well. The UGT1A1*28 polymorphism was detected more often among neonates with elevated bilirubin. Hyperbilirubinemia was diagnosed more frequently in boys. Conclusion: Polymorphisms of the UGT1A1 gene frequently co-exist in neonates. The presence of UGT1A1*28 polymorphism and male gender seem to predispose to neonatal hyperbilirubinemia.
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