In the present study, we evaluated the effect of ribavirin and metformin on the sensitivity of oxaliplatin and 5-fluorouracil (5-FU) on colon cancer.
Cell viability of two commercially available ...colon cancer cell lines (HT29 and HCT116) were analyzed by sulforhodamine B (SRB) assay.
A clinically achievable and nontoxic concentration of ribavirin and metformin showed a significant synergistic effect on oxaliplatin in HT29 and HCT116 cell lines. Ribavirin showed a synergistic effect on oxaliplatin in HT29 (R = 2.93, P < 0.001) and HCT116 (R = 1.71, P < 0.001), while only in HT29 metformin synergized with oxaliplatin by 2.66 (± 0.28, P < 0.01). In addition, both cell lines showed significant differences in response to Compound 968, inhibitor of mitochondrial glutaminase activity.
The data suggested that these cell lines not only turn to metabolic different sustainability process after oxaliplatin treatment but that they also have different basal metabolic requirements of glutamine in vitro which can be exploits in the future for colorectal cancer (CRC) treatment and further studies are required.
Background: Glutathione S-transferases (GSTs) are drug-metabolising enzymes involved in biotransformation of carcinogens, drugs, xenobiotics and oxygen free radicals. Polymorphisms of GST genes ...contribute to inter-individual and population variability in the susceptibility to environmental risk factors, cancer predisposition and pharmacotherapy responses. However, data about GST variability in Argentina are lacking.
Aim: The purpose was to determine the prevalence of GSTM1, GSTT1 and GSTP1 polymorphisms in the general population from a central region of Argentina and to perform inter-population comparisons.
Subjects and methods: GSTM1 and GSTT1 gene deletions and GSTP1 c.313A > G were genotyped by PCR assays in 609 healthy and unrelated Argentinians.
Results: The frequencies of variant genotypes in Argentinians were GSTM1-null (45%), GSTT1-null (17%) and GSTP1-GG (11%). GSTM1-present genotype was significantly associated with GSTP1-AG or GSTP1-GG variants (p = 0.037; p = 0.034, respectively). Comparison with worldwide populations demonstrated that the GST distributions in Argentina are similar to those reported for Italy and Spain, whereas significant differences were observed regarding Asian and African populations (p < 0.001).
Conclusion: This study has determined, for the first time, the normative profile of three pharmacogenetically relevant polymorphisms (GSTM1, GSTT1 and GSTP1) in the largest Argentinian cohort described to date, providing the basis for further epidemiological and pharmacogenetic studies in this country.
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Dostopno za:
DOBA, FSPLJ, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Malfunction of mismatch repair (MMR) genes produces nuclear genome instability (NGI) and plays an important role in the origin of some hereditary and sporadic human cancers. The appearance of ...non-inherited microsatellite alleles in tumor cells (microsatellite instability, MSI) is one of the expressions of NGI. We present here data showing mitochondrial genome instability (mtGI) in most of the human cancers analyzed so far. The mtDNA markers used were point mutations, length-tract instability of mono- or dinucleotide repeats, mono- or dinucleotide insertions or deletions, and long deletions. Comparison of normal and tumoral tissues from the same individual reveals that mt-mutations may show as homoplasmic (all tumor cells have the same variant haplotype) or as heteroplasmic (tumor cells are a mosaic of inherited and acquired variant haplotypes). Breast, colorectal, gastric and kidney cancers exhibit mtGI with a pattern of mt-mutations specific for each tumor. No correlation between NGI and mtGI was found in breast, colorectal or kidney cancers, while a positive correlation was found in gastric cancer. Conversely, germ cell testicular cancers lack mtGI. Damage by reactive oxygen species (ROS), slipped-strand mispairing (SSM) and deficient repair are the causes explaining the appearance of mtGI. The replication and repair of mtDNA are controlled by nuclear genes. So far, there is no clear evidence linking MMR gene malfunction with mtGI. Polymerase γ (POLγ) carries out the mtDNA synthesis. Since this process is error-prone due to a deficiency in the proofreading activity of POLγ, this enzyme has been assumed to be involved in the origin of mt-mutations. Somatic cells have hundreds to thousands of mtDNA molecules with a very high rate of spontaneous mutations. Accordingly, most somatic cells probably have a low frequency of randomly mutated mtDNA molecules. Most cancers are of monoclonal origin. Hence, to explain the appearance of mtGI in tumors we have to explain why a given variant mt-haplotype expands and replaces part of (heteroplasmy) or all (homoplasmy) wild mt-haplotypes in cancer cells. Selective and/or replicative advantage of some mutations combined with a severe bottleneck during the mitochondrial segregation accompanying mitosis are the mechanisms probably involved in the origin of mtGI.
The aim of this study was to determine the existence of association between the genetic polymorphisms of metabolizing genes GSTM-1, GSTT-1, and NAT-2, and the presence of mitochondrial genome ...instability (mtGI) in breast cancer cases. Ninety-four pairs of tumoral/nontumoral breast cancer samples were analyzed. Our samples showed 40.42% of mtGI by analysis of two D-loop region markers, a (CA)n mtMS starting at the 514-bp position, and four informative MnlI sites between the 16,108-16,420-bp. GSTM-1 null genotype has shown a significant association with mtGI presence (chi(2) = 7.62; P = 0.006) in breast cancer cases; moreover, these genotypes also are related to an increased risk for mtDNA damage (odds ratio OR = 3.71 1.41-9.88; 95% Cornfield confidence interval CI). These results suggest that the absence of GSTM-1 enzymatic activity favors chemical actions in damaging the mtDNA. Analysis of GSTT-1 and NAT-2 polymorphisms showed no association with mtGI (chi(2) = 0.03; P = 0.87 and chi(2) = 2.76; P = 0.09, respectively). The analysis of invasive breast cancer cases showed mtGI in 74.36% of ILC cases (29 of 39 samples), and in only 18.75% (9 out of 48) IDC cases; this result suggests a possible relation between mtDNA mutations and variations in molecular pathways of tumor development.
Approximately 15–25% of male infertility cases carry extensive azoospermic factor (AZF) deletions. Moreover, about 80% of Finnish testicular germ cell tumors (TGCT) and about 23–25% of TGCTs from ...other geographic regions carry short and interstitial AZF deletions. In infertility cases the AZF deficiency occurs in the germ cells of the proband father giving rise to mosaic sperm populations comprising non-deleted and deleted sperms. Fertilization of an ovocyte by a Y deleted sperm will give rise to an AZF-deleted and infertile F1 male. In TGCTs the AZF deletions take place in the initial stages of embryogenesis producing individuals that are a mosaic of Y deleted and non-deleted cell lineages. Carcinoma in situ (CIS) is a premalignant lesion that some believe may develop in gonads of male embryos before the ninth week of age due to transformation of a totipotent primordial germ cell. If the transformed cell carries AZF deletions the resultant CIS will also have Y deletions. CIS will differentiate into seminoma or into embryonal carcinoma and non-seminomas in about 1×10−3 of the young adults carrying premalignant CIS outgrowths; if the CIS lesion has AZF deletions the derived forms of testicular cancer will also exhibit these deletions. AZF deletions play no role in the development of testicular cancers. On the other hand, they are a marker of Y chromosome instability and eventually of a more generalized pattern of genome instability associated with the appearance of TGCT. Genetic factors such as malfunction of metabolizing genes, DNA repairing genes, Y-linked or X-linked genes have been considered as possible causes of AZF deletions in testicular cancer. Yet, the exact identification of the genes involved remains elusive. AZF deletions have also been identified in non-Hodgkin lymphomas and in colorectal cancers, two forms of malignancy that have been found to be associated with TGCTs.
We analyzed 40 pairs of breast normal/cancer tissues for the presence of mitochondrial (mt) genome instability and nuclear MSI in tumor cells. As mt, markers we used a (CA)n mt microsatellite (MS) ...starting at the 514-bp position of the D loop region and 4 informative MnlI sites located between the 16,108- and 16,420-bp positions of the D loop region. Nuclear microsatallite instability (MSI) was tested with 8 (CA)n MS, syntenic for the 13q chromosome arm. Moreover, we tested the spontaneous frequency of mtMSI and mt-MnlI mutations in 459 mother/descendant events. Mutations of mt-MnlI sites were found in 19 of 40 (47.5%) breast tumors, representing a 216-fold increase over the spontaneous rate in the female germline. Instability of the mtMS occurred in 17 of 40 (42.5%) breast cancers, which implies a 16-fold increase over the rate of spontaneous mutations. Nuclear MSI was found in 20 of 40 (50%) cases. In 15 of these cases the MSI was restricted to one locus, whereas in 5 instances the change of alleles was detected in 2 or 3 loci. Analysis of the correlation between mt and nuclear mutations showed no significant associations, suggesting that different systems are responsible for mt and nuclear genome instability in tumor cells. We propose that the two main mechanisms producing mtRFLP and mtMSI are damage by free radicals and error repair by the polymerase gamma, the first mechanism being a major cause of MnlI mutations and a secondary cause of mtMSI.
Mitochondrial DNA 4977-bp deletion (common deletion) has been associated with ageing human tissues and a few studies have demonstrated their presence in breast cancer patients too; however, no ...previous publication evaluated both topics in the same samples group. First, when analyzing 95 breast cancer patients, we found a higher percentage of cases carrying the deletion in non-tumoral tissue 73.68% (70/95) than in the tumoral counterparts 45.26% (43/95), showing that the 4977-bp deletion is a phenomenon which commonly appear first in the non-tumoral breast tissue rather than tumoral tissue. Secondly, we analyzed and compared the ageing related distribution of the common deletion rates, in a control group of 199 samples (ages ranging from 10 to 80 years), with those found in cancer patients. Significant correlation was observed in control cases, between individual age ranges and rates of deletion (chi2: 23.21 and p<0.01). In contrast, non-tumoral breast tissue did not show a pattern of correlation, chi2: 0.042 and p: 0.837. However, interestingly, we found that the risk of having deleted mtDNAs was higher for non-tumoral breast samples than for the control group samples, OR: 2.32 1.22-4.42, 95% CI; this could be reflecting that other mechanisms are involved in mitochondrial genome deletion increased rate detected in breast cancer cases, than the normal ageing process.
Aicuña is a village in the northwest of Argentina, located about 300 km south of La Rioja city, in the province of La Rioja. The population of Aicuña derives from a founder couple established in the ...uninhabited Aicuña valley in the early years of the 17th century. Due to land ownership litigation, the descendants maintained a well-documented genealogy that extends for 12 generations, comprising more than 8,000 individuals. From the historical pedigree of Aicuña, we selected 14 males with direct patrilineal descent from the 2 most ancient male founders, and 23 donors (9 females and 14 males) with direct matrilineal descent from the most ancient female founder. All 3 founders lived in the 17th century. We collected DNA from buccal swabs and characterized the mitochondrial DNA (mtDNA) and Y haplotypes using 14 Y-specific markers, 11 mtDNA polymorphic markers and sequencing of the mt hypervariable regions 1 and 2. We found four different Y haplotypes: Y1 and Y2 haplotypes of European origin corresponding to the founder ancestors Francisco Páez de Espinoza and Apolinario Ormeño, which were shared by 6 and 3 donors, respectively. Three males selected as Ormeño patrilineal descendants showed a different Y haplotype (Y3), probably originated by erroneous paternity registration due to illegitimacy. The remaining case (haplotype Y4), also assumed to belong to the Ormeño lineage, was probably also due to an erroneously registered paternity. Twenty-two donors showed an association of mtDNA markers corresponding to the Amerindian haplotype A2. The founder of this matrilineage could be traced back for more than 14 generations. The haplotype B of one remaining female did not correspond with the historical pedigree and could be due to an error in the genealogy registration. Our results showed an 85% agreement between conventional and molecular genealogies, with mtDNA markers being Amerindian, and Y markers being European. The methodology used in this report is a tool which could potentially be employed as a precedent for land ownership by Aicuña villagers and Amerindian populations.
We tested for azoospermia factor (AZF) deletions 17 loci corresponding to AZF subintervals a-d in 17 cases of testicular tumors occurring in Finns. While DNA samples from 48 CEPH and 32 Finnish males ...showed no deletions, patients with testicular cancer displayed AZF deletion mosaicisms in various non-tumor tissues (13 cases) and specific deletion haplotypes in tumor tissues (10 cases). Two of the cases with AZF deletions were testicular non-Hodgkin lymphomas indicating that Y-microdeletions appear also in malignancies other than seminoma and non-seminoma tumors. In good agreement with this assumption, we detected one AZF deletion in normal cells from 1 of 5 HNPCC cases, heterozygous for an MLH1 mutation. We propose that AZF deletions occur in early embryogenesis due to mutations of TSPY, mismatch repair (MMR), or X-specific genes. Since fathers of testicular, tumor cases did not exhibit AZF deletions, we assumed they were not carriers of the mutation inducing AZF deletion-mosaicisms. Therefore, tumor cases should have received the MMR gene or X mutations via the maternal lineage, or for the case of TSPY and MMR genes via a sperm carrying a mutation occurred in the paternal germ-cell line. We consider AZF microdeletions in non-tumor cells to be part of a broader pattern of chromosome instability producing susceptibility to testicular tumors. Clonal transformation and expansion of one of these tumor-susceptible cell lineages give rise to testicular tumors showing genome anomalies characteristic of testicular cancers (i12p, LOH and genetic imbalance for various autosomal regions, Y- and autosomal MSI, specific AZF deletion haplotypes).
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