Biomedical subjects

K Pavelić

Publications and source records attributed to K Pavelić.

At least 19 recordsLinked to original sources

PubMed2006

Synthesis and in vitro antitumor effect of diclofenac and fenoprofen thiolated and nonthiolated polyaspartamide-drug conjugates.

This paper reports the synthesis and antiproliferative effects of new thiomer-diclofenac and fenoprofen conjugates, hydrophilic, bioadhesive, polymeric prodrugs, as well as antiproliferative effects of diclofenac, fenoprofen and a series of previously described polymer-fenoprofen conjugates on five tumor cell lines. Thiolated and nonthiolated polyaspartamides were the chosen polymeric components. Drug-loading ranged from 5.6 to 22.4%, and the amount of SH groups ranged from 6.9 to 45.6micromol g(-1). Tensile studies demonstrated a clear correlation between the amount of thiol and the mucoadhesive properties of the conjugates. The growth-inhibitory activity of the tested polymer-drug conjugates demonstrates that polyaspartamide-type polymers, especially thiolated polymers, enable inhibition of tumor cell growth with significantly lower doses of the active substance.

Antineoplastic Agents↗

PubMed2005

NF1 gene loss of heterozygosity and expression analysis in sporadic colon cancer.

BACKGROUND AND AIMS: Colon cancer tumorigenesis is a multistep process of mutation accumulation in a number of oncogenes and tumour suppressor genes. NF1 gene protein, neurofibromin, acts as a tumour suppressor by turning the active form of Ras into an inactive form. This molecular switch has an important role in the control of the cell cycle and differentiation, and changes in Ras activity are present in many different cancers. This is the first study to investigate the role of NF1 in sporadic colon cancer. METHODS: We investigated loss of heterozygosity (LOH) at the NF1 locus. Real time reverse transcription-polymerase chain reaction was used to determine NF1 mRNA expression in tumours and corresponding normal tissue. Expression of neurofibromin was analysed by immunohistochemistry. Relative ratio of NF1 mRNA type I and II isoform expression was also examined. RESULTS: LOH of the NF1 gene was detected in 20.7% of heterozygous samples. NF1 mRNA expression was significantly increased in tumour tissue compared with corresponding normal tissue (p = 0.04291). There was a statistically significant increase in NF1 type I isoform expression (p = 0.0005) in tumour tissue compared with corresponding normal colon tissue. NF1 isoform type II was predominantly expressed in normal tissue while the NF1 isoform type I prevailed in tumour samples. The transition from dominant expression of isoform type II in normal mucous tissue 15 cm away from the tumour to dominant expression of isoform type I in tumour tissue itself was detected. Total neurofibromin expression increased as tumours were more advanced but expression of wild-type neurofibromin remained the same. CONCLUSIONS: Our findings suggest that the NF1 gene may play a role in the development and progression of colon cancer and the NF1 gene may be a potential tumour marker and a new potential target for colon cancer therapy.

Adenocarcinoma↗

PubMed2004

Synthesis, crystal structure and antiproliferative evaluation of some new substituted benzothiazoles and styrylbenzothiazoles.

The multistep synthesis of a series of new substituted-benzothiazoles as hydrochloride or quaternary salts is described. 6-Amidino substituted 2-aminobenzothiazoles (5, 6), N-methyl-2-(4-cyanostyryl)benzothiazolium iodide (8), cyano-substituted-2-styrylbenzothiazoles (9-11) and amidino and bis-amidino-substituted 2-styrylbenzothiazoles (12-17) were prepared. The crystal structure of amidino derivative (6) was determined by single crystal X-ray analysis. All new prepared compounds were tested on the cytostatic activities against malignant cell lines: (SW620, colon carcinoma; Hep2, laryngeal carcinoma; HBL, melanoma; HeLa, cervical carcinoma and WI38, human normal fibroblasts). The compounds exerted a different inhibitory effect, depended on concentration and type of the cells. The best inhibitory effect was achieved with compounds (12-15), with slight differences among them. All of them inhibited the growth of examined tumor cell lines and also normal fibroblasts. Other examined compounds exhibited a moderate inhibitory effect, depending on type of the cells. Majority of them inhibited the growth of HeLa cells and WI38.

Benzothiazoles↗

PubMed2004

nm23-H1 expression and loss of heterozygosity in colon adenocarcinoma.

BACKGROUND: The discovery that genetic alterations in oncogenes and tumour suppressor genes accompany tumour formation in many human tumours has encouraged the search for genes that promote or suppress tumour spread and metastasis; nm23 is a promising candidate for a metastasis suppressing gene. AIMS: To evaluate whether expression of nm23-H1 protein or loss of heterozygosity (LOH) of the nm23-H1 gene is associated with colon cancer progression. MATERIALS/METHODS: Paraffin wax embedded tissue sections were analysed immunohistochemically. DNA isolated from normal and tumour tissue was used for LOH analysis using a variable nucleotide tandem repeat (VNTR) marker located in the untranslated 5' region of the nm23-H1 gene. RNA isolated from tumour and normal tissue was used for "real time" RT-PCR. RESULTS: Of 102 adenocarcinomas examined, 58.8% stained weakly for nm23-H1 protein. There was a negative correlation between nm23-H1 positivity and tumour histological grade. In VNTR analysis, 70.2% of patients were informative and 27.4% of tumours had nm23-H1 LOH. There was a positive correlation between nm23-H1 LOH and both tumour histological grade and Dukes's stage. Expression of nm23-H1 mRNA was increased in 22 of 30 colon tumours compared with normal tissue. No significant correlation was found between nm23-H1 mRNA expression and histological grade or Dukes's stage of tumours. CONCLUSIONS: These findings suggest that nm23-H1 protein expression in early stages may have a role in suppressing metastasis in sporadic colon cancer, whereas at a later stage both reduced nm23-H1 protein expression and LOH of the nm23-H1 gene may play role in colon cancer progression and metastasis.

Adenocarcinoma↗

PubMed2002

Screening for fragile X syndrome: results from a school for mentally retarded children.

UNLABELLED: Fragile X syndrome is the most common inherited form of familial mental retardation. The purpose of this study was to identify yet unrecognized fragile X individuals and to estimate the frequency of both the FRAXA and FRAXE forms of the disease in a population of mentally retarded children attending a special school in Croatia. The results are reported of molecular screening of 114 children with mild to severe mental retardation. Three individuals (2.6%) with the FRAXA form of the fragile X syndrome and one boy (0.9%) with FRAXE mental retardation were detected; a total of four newly diagnosed fragile X families were identified. Closer clinical examination revealed that behavioural and speech disturbances were clearly present among all fragile X cases (both FRAXA and FRAXE), indicating that these features could be additional diagnostic criteria for the preselection of individuals at risk. CONCLUSION: Fragile X screening among mentally retarded children attending a special school should be highly encouraged to reveal the cause of mental retardation and to detect yet unrecognized fragile X individuals. The frequency of fragile X syndrome in a such population in Croatia was found to correlate with similar results from previous studies. However, since at the time of diagnosis all affected families had a second or even a third child born, earlier diagnosis should be considered to provide greater benefit to fragile X families.

Adolescent↗

PubMed2002

Novel alleles of the D16S752 polymorphic genetic marker linked to E-cadherin gene--a potential population marker.

Seven DNA variants that polymorphic genetic marker D16S752 reveals in Croatian population are reported in this paper. The marker is a GATA tetranucleotide repeat linked to human E-cadherin gene (CDH1). Prior studies involving this marker revealed only four DNA allele variants. The reported DNA variants contribute to the collection of hypervariable DNA polymorphisms data useful in the field of anthropological and population genetic and forensic medicine.

Cadherins↗

PubMed2001

Natural zeolite clinoptilolite: new adjuvant in anticancer therapy.

Natural silicate materials, including zeolite clinoptilolite, have been shown to exhibit diverse biological activities and have been used successfully as a vaccine adjuvant and for the treatment of diarrhea. We report a novel use of finely ground clinoptilolite as a potential adjuvant in anticancer therapy. Clinoptilolite treatment of mice and dogs suffering from a variety of tumor types led to improvement in the overall health status, prolongation of life-span, and decrease in tumors size. Local application of clinoptilolite to skin cancers of dogs effectively reduced tumor formation and growth. In addition, toxicology studies on mice and rats demonstrated that the treatment does not have negative effects. In vitro tissue culture studies showed that finely ground clinoptilolite inhibits protein kinase B (c-Akt), induces expression of p21WAF1/CIP1 and p27KIP1 tumor suppressor proteins, and blocks cell growth in several cancer cell lines. These data indicate that clinoptilolite treatment might affect cancer growth by attenuating survival signals and inducing tumor suppressor genes in treated cells.

Adjuvants, Pharmaceutic↗

PubMed2001

Loss of heterozygosity of DPC4 tumor suppressor gene in human sporadic colon cancer.

We investigated the prevalence of DPC4 loss of heterozygosity in sporadic colorectal cancer. Thirty-six cases of human sporadic colon carcinoma and corresponding normal tissue samples were examined to evaluate loss of heterozygosity at the DPC4 tumor suppressor locus using variable nucleotide tandem repeat (VNTR) analysis and three polymorphic markers. From 36 analyzed samples 35 (97%) were heterozygous or informative. Loss of heterozygosity at the DPC4 locus was detected in 18 (51%) of informative tumor DNAs. The DPC4 LOH was more frequent in smaller tumors (<5 cm) than in larger ones. There was no correlation between DPC4 LOH and age or sex of patients. There was a negative correlation between DPC4 LOH and histological grade or Dukes' stage of tumors, but without statistic significance. Observed results are in agreement with the view that malignant progression is consequence of many genetic changes. It can be concluded that inactivation of the DPC4 gene plays a role in a multistep process of outgrowth and progression of colon cancer.

Aged↗

PubMed2001

Submerged gel electrophoresis on Spreadex gels--a new method for APC gene mutation detection.

Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disease. Patients with FAP develop hundreds to thousands of adenomatous polyps in the colon and rectum during their 2nd or 3rd decades, and one or more of them progress to cancer if left without surgical treatment. The gene responsible for FAP was identified in 1991 and termed the APC (adenomatous polyposis coli) gene. Following identification of APC, a number of germ-line mutations responsible for the development of the disease were found. The purpose of this study was to determine the usefulness of a new method, submerged gel electrophoresis, in the detection of the most-frequent mutation of the APC gene [5-base pair (bp) deletion in codon 1309], especially in the presymptomatic diagnosis of FAP. Genomic DNAs were isolated from peripheral blood of patients and their relatives. We used two methods, electrophoresis on polyacrylamide gel and submerged gel electrophoresis, for the identification of APC gene codon 1309 mutation. After only 110 min PCR fragments of 91 bp and 86 bp (5-bp deletion) were completely resolved on a Spreadex EL300 gel. Our results showed that electrophoresis using Spreadex gels provides a simple and rapid non-radioactive method for determination of the most-frequent germ-line mutations in the APC gene.

Adenomatous Polyposis Coli↗

PubMed2001

Recent advances in molecular genetics of breast cancer.

Breast cancer is among the most common tumors affecting women. It is characterized by a number of genetic aberrations. Some 5-10% of cases are thought to be inherited. The hereditary breast and ovarian cancer syndrome includes genetic alterations of various susceptibility genes, particularly BRCA1 and BRCA2. Breast tumors of patients with germ-line mutations in the BRCA1 and BRCA2 genes have more genetic defects than sporadic breast tumors. Here we review new findings in the function of BRCA1 gene function. Accumulation of somatic genetic changes during tumor progression map follows a specific and more aggressive pathway of chromosome damage in these individuals. A major BRCA1 downstream target gene is the DNA damage-responsive gene GADD45. Induction of BRCA1 triggers apoptosis by activation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK). BRCA1 interacts with SWI/SNF, a chromatin remodeling complex important in gene expression. Recent advances in genomics and bioinformatics, particularly in DNA-sequencing approaches and DNA-chip technology are expected to improve identification of small molecules, which might be drugable targets. New knowledge about the genetic portrait of breast tumor is coming from differential gene expression profiling using microarrays. Human genome studies, as well as development of "DNA chips," provide a window for observing patterns of gene activity in cells, which will contribute to more accurate cancer classification. However, substantial work connected with analytical and statistical tools must still be carried out to confirm the function of differentially expressed genes. Knowledge of the molecular characteristics of breast tumor has already started to make possible the identification of breast cancer patients who could benefit from therapies that target those features. Progress in basic research into signaling provides the opportunity to attack at least some signal-transduction targets involved in proliferation, survival, invasion, angiogenesis, metastasis, and resistance. Exciting knowledge in breast cancer biology is rapidly accumulating in parallel with recent developments in rational selection and validation of relevant targets that provide unique opportunities for development of "intelligent" therapeutics.

BRCA1 Protein↗

PubMed2001

Effect of the nonsteroidal anti-inflammatory drug indomethacin on proliferation and apoptosis of colon carcinoma cells.

PURPOSE: Nonsteroidal anti-inflammatory drugs lower the incidence of and mortality from colon cancer. In this paper, we present the effect of indomethacin on growth inhibition and alterations in the expression of several genes involved in cell cycle and apoptosis in CaCo-2 colon adenocarcinoma cells. METHODS: We used the MTT test to evaluate the effect of indomethacin on the proliferation rate of colon cancer and normal fibroblast cells in vitro. The expression of c-myc oncoprotein and p53 and p27 suppressor proteins was examined using the immunocytochemical method. RESULTS: We have shown that indomethacin reduces the proliferation rate of CaCo-2 colon cancer cells (up to 60% at the concentration of 4 x 10(-4) M), alters their morphology, and induces cell death by apoptosis. The most pronounced inhibitory effect was observed at the concentration of 6 x 10(-4) M where the growth was completely suppressed. However, the growth of normal fibroblasts (Hef 522) was much less inhibited (about 30% of inhibition at the concentration of 6 x 10(-4) M). Indomethacin reduces the proliferation rate and induces apoptosis in CaCo-2 colon cancer cells through enhanced expression of c-myc, p53, and p27 proteins. CONCLUSIONS: This is the first report about p27-increased expression in colon carcinoma cells induced by indomethacin treatment. Increased expression of p27 represents a new mechanism of apoptosis in cells treated with NSAIDs (indomethacin). This effect probably contributes to the anti-proliferative effect on colon cancer cells in vitro.

Adenocarcinoma↗

PubMed2001

A simple and rapid analysis of triplet repeat diseases by expand long PCR.

It is now known that 15 monogenic, mostly neurological, disorders are caused by the same type of mutations that occur in trinucleotide repeat sequences in certain genes. Since they share a nonspecific and variable phenotype, the accurate diagnosis could be made only by DNA analysis. We developed an Expand Long PCR assay that provides more reliable molecular diagnosis of such disorders. Its main characteristics are robust amplification of expanded alleles, simplicity, low cost and speed. We suggest the use of Expand Long PCR for routine molecular diagnosis of triplet repeat diseases, and present such analysis of the fragile X syndrome, myotonic dystrophy and Huntington's disease.

Base Sequence↗

PubMed2001

Aberration of FHIT gene is associated with increased tumor proliferation and decreased apoptosis-clinical evidence in lung and head and neck carcinomas.

BACKGROUND: Human FHIT (fragile histidine triad) gene is highly conserved gene homologous to a group of genes identified in prokaryotes and eukaryotes. Loss of FHIT function may be important in the development and/or progression of various types of cancer. MATERIALS AND METHODS: We undertook a clinical study to analyze the relation between aberrant function of FHIT gene, tumor cell proliferation, and intensity of apoptosis as well as prognostic output in lung and squamous cell head and neck carcinoma (HNSCC). Status of FHIT gene, expression of p21waf1, intensity of apoptosis, and cell proliferation were analyzed in HNSCC and lung carcinoma tissues by molecular genetic methods, immunohistochemistry, [3H]-thymidine labeling method, and FACScan analysis in frozen and paraffin-embedded tissue sections. RESULTS: The majority of the malignant lung and HNSCC lesions displayed aberrant expression of FHIT gene, followed by low or negative expression of p21waf1, and increased intensity of cell proliferation. Similar results were obtained on synchronous combinations of normal, precancerous, and cancerous head and neck tissues. The observed changes increased with progression of these lesions. We examined tumor and corresponding normal tissue samples for microsatellite markers D3S1300 and D3S4103 to evaluate the loss of heterozygosity (LOH) at the FHIT gene loci. We found high percentage of LOH in both lung tumors and HNSCC (75% for D3S1300 and 79% for D3S4103 in lung cancer, and 87% for D3S1300 and 78% for D3S4103 in HNSCC). The median survival time of the patients suffering from lung cancer without FHIT protein expression was 22.46 months and that of the patients with FHIT expression 36.04 months. FHIT-negative cases tended to correlate with a worse prognosis, but this was not statistically significant. Median survival time of HNSCC patients without FHIT protein expression was 30.86 months and that of the patients with FHIT expression was 64.04 months (p < 0.05). CONCLUSIONS: Our results show a correlation between aberrant FHIT expression, a low rate of apoptosis, and high tumor cell proliferation. Aberrant FHIT gene could be a prognostic marker in lung cancer.

Acid Anhydride Hydrolases↗

PubMed2000

Increased activity of nm23-H1 gene in squamous cell carcinoma of the head and neck is associated with advanced disease and poor prognosis.

The present study was undertaken to determine whether the nm23-H1 gene is expressed in squamous cell carcinoma of the head and neck (SCCHN) and whether the level of nm23-H1 protein or mRNA in cells vary as they progress to a more malignant phenotype. Of the 120 SCCHN studied 54 (45%) stained positively for nm23-H1 protein. Protein expression was significantly higher in more advanced stages of disease. Expression of nm23-H1 was significantly higher in cancer tissues than in normal, adjacent tissue, dysplasia, or carcinoma in situ. The nm23-H1 rate increased with progression of synchronous lesions from dysplasia to carcinoma in situ and finally to carcinoma (P<0.05). Northern blot analyses of tissues with various clinicopathological characteristics also revealed differences in nm23-H1 mRNA expression. When levels of nm23-H1 mRNA were compared to tumor stage, intensity of expression was found to be higher in stages 3 and 4 than stages 1 and 2 (P<0.01). Malignant tumors had a higher level of mRNA nm23-H1 expression than normal or premalignant tissues. The nm23-H1 negative patients survived significantly longer than nm23-H1 positive ones (P<0.05). To study the possible relationship between nm23-H1 gene expression and cell growth rate in tumor cells, the mRNA level in each tumor was compared to proliferative activity. The nm23-H1 gene expression levels were directly related to the [3H]thymidine labeling index in tumor cells (R=0.6681). Our results strongly indicate that the nm23-H1 gene is involved in progression of SCCHN. Together with results obtained on lung cancer, our observations suggest that increased expression of nm23-H1 in cancers of the upper aerodigestive tract may have different implications than elsewhere in the body.

Adult↗

PubMed2000

Expression of erbB-3 protein in colorectal adenocarcinoma: correlation with poor survival.

BACKGROUND/AIMS: The family of erbB receptors includes four transmembrane glycoproteins with tyrosine kinase activity. These receptors are widely expressed in normal tissues, but they also have been implicated in the development of several human adenocarcinomas. c-erbB-3/HER-3 has been detected to a greater or lesser extent in many tissues from the digestive, urinary, reproductive and respiratory tracts. The overexpression of c-erbB-3/HER-3 protein has also been shown in 53%-88% of colorectal adenocarcinomas. In this study we investigated the expression of the c-erbB-3/ HER-3 gene product in colorectal tumour samples, and compared the results obtained with several clinicopathological parameters, including the survival of patients. METHODS: Paraffin-embedded tissue sections were analysed immunohistochemically, using monoclonal antibody RTJ1 to human erbB-3 protein. Antibody RTJ1 specificity was confirmed by immunoprecipitation followed by Western blotting analysis. Amplification of the erbB-3 oncogene was tested by dot-blot hybridization. RESULTS: Adenocarcinomas of the colon were positive for erbB-3 protein in 78% of samples examined. Dot-blot analysis showed no amplification of the erbB-3 gene in colon adenocarcinomas. Statistical analysis showed that patients with tumours that could not be stained for erbB-3 protein survived significantly longer (P<0.05) than patients with tumours staining positive for the erbB-3 protein. A Cox proportional-hazards model with stepwise variable selection identified age, sex and erbB-3 expression as important prognostic factors. CONCLUSION: These findings demonstrate that erbB-3 protein expression could serve as a prognostic factor in colorectal malignancies.

Adenocarcinoma↗

PubMed2000

Comparison of five different polymerase chain reaction methods for detection of human papillomavirus in cervical cell specimens.

The polymerase chain reaction (PCR) methods enable the detection of large number of human papillomavirus (HPV) genotypes that infect the anogenital tract. In this study, two groups of cervical scrapes with abnormal cytomorphology were analysed. The first group was tested with three sets of consensus primers located within the L1 region of HPV genome, MY09/MY11 (i.e. MY), L1C1/L1C2-1/L1C2-2 (i.e. LC) and pI-1/pI-2 (i.e. pI) primer sets, while the second group of samples, which were all negative with the MY primers, was tested further with the LC primers, as well as with the GP5/GP6 (i.e. GP) primers. The GP primers were used in the nested PCR following amplification with the MY primers (i.e. MY/GP nested PCR). Samples from both groups were also tested with type-specific primers for HPV types 6/11, 16, 18, 31 and 33. In the first study group (N=164) there were 76.2% positive results obtained with at least one set of consensus primers. There were 62.2, 39, 62.2 and 59.1% positive results obtained with the MY, the pI, the LC and the HPV type-specific primer sets, respectively. The best results were obtained when both the MY and the LC primer sets were used, because in combination they detected 75% positive samples compared to 62.2% when used alone. There were 2. 4% samples negative with all consensus primers, but positive with one of the HPV type-specific primers, which increased the overall positivity rate to 78.6%. In the second study group (N=250) there were 8.4, 38.8 and 4% samples positive with the LC primers, the nested MY/GP and the HPV type-specific primer sets, respectively. Thus, the use of the MY/GP nested PCR increased significantly the positivity rate of HPV DNA detection and should be used for samples with a low copy number of HPV DNA. In conclusion, the following diagnostic protocol would be appropriate for detection of cancer-related HPVs: preselection of samples with the MY and the LC primers, additional amplification of the MY- and the LC-negative samples with the MY/GP nested PCR and HPV typing of consensus PCR-positive samples with the HPV type-specific primers.

Adolescent↗

PubMed2000

Immunoprotective properties of peptidoglycan monomer linked with zinc in cholestatic jaundice.

BACKGROUND: Previously it was shown that a new immunostimulator, peptidoglycan monomer linked with zinc (PGM-Zn), might have immunocorrective and hepatotropic effects. Owing to this in the present study we investigated its effects on jaundice-induced immunodysfunction, which might be responsible for serious peri- and postoperative complications in biliary obstruction. METHODS: In vivo effects of PGM-Zn were analyzed in mice subjected to common bile duct ligation (CBDL), where we estimated phenotypic profile and cell cycle of thymocytes, splenocytes and phagocytic function of peritoneal macrophages. In vitro effects of PGM-Zn were evaluated on blastogenesis of human peripheral blood mononuclear cells (PBMNC), obtained from healthy donors and stimulated with anti-CD3 monoclonal antibody and/or PMA, in the presence or absence of jaundice serum obtained from patients with biliary calculosis. RESULTS AND DISCUSSION: Jaundice induced marked disarrangement of lymphatic homeostasis, which at several points might be blocked by PGM-Zn. In mice it delayed the CBDL-induced decline of CD4+ CD8+ thymocytes, decreased the proportion of CD8+ T cells, and increased the percentage of CD4- CD8- thymocytes, augmenting simultaneously the proportion of thymic cells in S and G2 + M phase of cycle. Similar hyperplastic reaction with increased percentage of CD4+, Ig+ and CD5+ cells was noticed in the spleen, together with the enhanced phagocytic ability of peritoneal macrophages. In human PBMNC jaundice reduced the percentages of CD3, CD5, CD4, CD8 and HLA-DR-expressing cells and increased the proportion of CD25 and perforin-positive lymphocytes. PGM-Zn given in vitro was able to abrogate the antiproliferative activity of jaundice serum on PMA and anti-CD3 + PMA-induced blastogenesis.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1999

Novel pyrimidine and purine derivatives of L-ascorbic acid: synthesis and biological evaluation.

The novel pyrimidine derivatives 1-6 of 2,3-dibenzyl-4,5-didehydro-5, 6-dideoxy-L-ascorbic acid were synthesized by the condensation of pyrimidine bases with 5,6-diacetyl-2,3-dibenzyl-L-ascorbic acid (DDA). Both N-9 (7) and N-7 (8) regioisomers were obtained in the reaction of 6-chloropurine with 5-acetyl-6-bromo-2, 3-dibenzyl-L-ascorbic acid (ABDA), while the reaction of 6-(N-pyrrolyl)purine with ABDA afforded exclusively the N-9 isomer 9. Structures of all newly prepared compounds were deduced from the chemical shifts in (1)H and (13)C NMR spectra, as well as connectivities in 2D homo- and heteronuclear correlation spectra. An unambiguous proof of the structure and conformation of 7 was obtained by X-ray crystallographic analysis. Compounds 1-9 were found to exert cytostatic activities against malignant cell lines: pancreatic carcinoma (MiaPaCa2), breast carcinoma (MCF7), cervical carcinoma (HeLa), laryngeal carcinoma (Hep2), murine leukemia (L1210/0), murine mammary carcinoma (FM3A), and human T-lymphocytes (Molt4/C8 and CEM/0), as well as antiviral activities against varicella-zoster virus (TK(+)VZV and TK(-)VZV) and cytomegalovirus (CMV). The compound 6 containing a trifluoromethyl-substituted uracil ring exhibited marked antitumor activity. The N-7-substituted purine regioisomer 8 had greater inhibitory effects on the murine L1210/0 and human CEM/0 cell lines than the N-9 isomer 7. Compound 9 with the 6-purine-substituted pyrrolo moiety had a more pronounced selective cytostatic activity against human (Molt4/C8 and CEM/0) cell lines than murine (L1210/0 and FM3A/0) and human (MiaPaCa2, MCF7, HeLa, and Hep2) tumor cell lines and normal fibroblasts (Hef522). The compound 6 exhibited the most potent antiviral activities against TK(+)VZV, TK(-)VZV, and CMV, albeit at concentrations that were only slightly lower than the cytotoxic concentrations.

Animals↗