Emerging role of p53, bcl-2 and telomerase activity in Egyptian breast cancer patients

Apoptotic cell death represents an important mechanism for the precise regulation of cell numbers, and a defense mechanism against tumor cells. Both bcl-2 and mutant p53 gene products have been involved in apoptotic pathways. On the other hand, cell proliferation capacity and tumorgenesis have been controlled by telomerase. The purpose of our study is to assess the prognostic significance of additional markers implicated in apoptosis and tumorgenesis. Fifty-one fresh tissue samples of primary breast carcinoma and 26 tissue samples of benign breast lesions were included in this study. Expression of bcl-2 in cell lysates and mutant p53 protein in nuclear fraction were measured by Oncogene Science EIA procedures. Telomerase activity was analyzed using the Telomerase-PCR-ELISA based on the TRAP (telomerase repeat amplification protocol) method. On the same specimens, steroid hormone receptors (ER and PgR) were measured in cytosol fraction using Abbott EIA assays. In addition, information regarding surgical-pathological features of the tumor was obtained. Univariate and Multivariate analysis was done to identify variables predictive of poor prognosis. Significant expression of bcl-2, mutant p53 proteins and relative telomerase activity were observed in malignant cases when compared to benign ones. Univariate analysis revealed significant association in the level of both mutant p53 and relative telomerase activity with tumor size and disease recurrence. Moreover, telomerase activity was significantly expressed in late stages than early ones. Multivariate analysis revealed that bcl-2, mutant p53, telomerase activity, PgR and age were independent prognostic factors. Among a panel of molecular genetic factors investigated, mutant p53 and relative telomerase activity were strongly associated with disease recurrence; hence they exert a significant prognostic role in breast cancer.     

Anti-HPV16 E2 protein T-cell responses and viral control in women with usual vulvar intraepithelial neoplasia and their healthy partners

T-cell responses (proliferation, intracellular cytokine synthesis and IFNγ ELISPOT) against human papillomavirus 16 (HPV16) E2 peptides were tested during 18 months in a longitudinal study in eight women presenting with HPV16-related usual vulvar intraepithelial neoplasia (VIN) and their healthy male partners. In six women, anti-E2 proliferative responses and cytokine production (single IFNγ and/or dual IFNγ/IL2 and/or single IL2) by CD4+ T lymphocytes became detectable after treating and healing of the usual VIN. In the women presenting with persistent lesions despite therapy, no proliferation was observed. Anti-E2 proliferative responses were also observed with dual IFNγ/IL2 production by CD4+ T-cells in six male partners who did not exhibit any genital HPV-related diseases. Ex vivo IFNγ ELISPOT showed numerous effector T-cells producing IFNγ after stimulation by a dominant E2 peptide in all men and women. Since the E2 protein is absent from the viral particles but is required for viral DNA replication, these results suggest a recent infection with replicative HPV16 in male partners. The presence of polyfunctional anti-E2 T-cell responses in the blood of asymptomatic men unambiguously establishes HPV infection even without detectable lesions. These results, despite the small size of the studied group, provide an argument in favor of prophylactic HPV vaccination of young men in order to prevent HPV16 infection and viral transmission from men to women.     

Assessment of titanium dioxide nanoparticles toxicity via oral exposure in mice: effect of dose and particle size

Objective: The aim of the present work is to evaluate the toxicity of titanium dioxide nanoparticles (TiO₂NPs) according to their doses and particle sizes.

Materials and methods: The effect of five days oral administration of TiO₂NPs (21 and 80?nm) with different doses (50, 250 and 500?mg/kg body weight) was assessed in mice via measurement of oxidative stress markers; glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and nitric oxide (NO), liver function indices; aspartate and alanine aminotransferases (AST and ALT), chromosomal aberrations and liver histopathological pattern.

Results: The results revealed drastic alterations in all the measured parameters and showed positive correlation with the gradual dose increment. In addition, the smaller particle size of TiO₂NPS (21?nm) had more adverse effect in all the selected biochemical parameters, genetic aberrations and histological investigations.

Conclusions: Toxicity of TiO₂NPs increases in a dose-dependent manner and vice versa with particles size. The evaluated biomarkers are good indicators for TiO₂NPs toxicity. More detailed studies are required before the recommendation of TiO₂NP_S as food additives.     

Prader-Willi syndrome: Methylation study or fluorescence in situ hybridization first?

Prader-Willi syndrome (PWS) is neurogenetic disorder involving the imprinting mechanism at 15q11-13 region. We report a 4-year-old girl who was referred to our laboratory to be investigated for clinical obesity, mental deficiency and respiratory problems. The patient was born for non-consanguineous and healthy biological parents. After normal pregnancy, the patient was delivered by cesarean section at full term, with a birth weight of 2500 g, and the height and head circumference were unknown. In neonatal stage, she presented severe hypotonia with feeding problems. Her developmental progress was delayed. She walked and developed speech at the age of 3 years. Since the age of 3 years, she presented severe dental problems. Methylation study had confirmed the diagnosis, and for detecting etiology, fluorescence in situ hybridization using probes for small nuclear ribonucleoprotein polypeptide N (SNRPN), which map inside the chromosomal region 15q11-15q13, was necessary to confirm the 15q11-15q13 deletion of paternal chromosome 15, which is the predominant genetic defect in PWS. In conclusion, we report this case with an objective to reinforce the necessity of analysis of DNA methylation within the 15q11-13 region, which is an important tool for the correct diagnosis among children presenting with neonatal hypotonia, mental deficiency and obesity.     

Biomphalaria alexandrina snails as immunogens against Schistosoma mansoni infection in mice

Despite effective chemotherapy, schistosomiasis remains the second largest public health problem in the developing world. Currently, vaccination is the new strategy for schistosomiasis control. The presence of common antigenic fractions between Schistosoma mansoni and its intermediate host provides a source for the preparation of a proper vaccine. The objective of this paper is to evaluate the nucleoprotein extracted from either susceptible or resistant snails to protect against schistosomiasis. The vaccination schedule consisted of a subcutaneous injection of 50 μg protein of each antigen followed by another inoculation 15 days later. Analyses of marker enzymes for different cell organelles [succinate dehydrogenase, lactate dehydrogenase (LDH), glucose-6-phosphatase, acid phosphatase and 5'-nucleotidase] were carried out. Energetic parameters (ATP, ADP, AMP, phosphate potentials, inorganic phosphate, amino acids and LDH isoenzymes) were also investigated. The work was extended to record worm and ova counts, oogram determination in the liver and intestine and the histopathological pattern of the liver. The nucleoprotein of susceptible snails showed reduction in worm and ova counts by 70.96% and 51.31%, respectively, whereas the nucleoprotein of resistant snails showed reductions of 9.67% and 16.77%, respectively. In conclusion, we found that the nucleoprotein of susceptible snails was more effective in protecting against schistosomiasis.     

Altered gene expression and methylation of the human chromosome 11 imprinted region in small for gestational age (SGA) placentae

Imprinted genes are known to be crucial for placental development and fetal growth in mammals, but no primary epigenetic abnormality in placenta has been documented to compromise human fetal growth. Imprinted genes demonstrate parent-of-origin-specific allelic expression that is epigenetically regulated i.e. extrinsic to the primary DNA sequence. To undertake an epigenetic analysis of poor fetal growth in placentae and cord blood tissues, we first established the tissue-specific patterns of methylation and imprinted gene expression for two imprinting clusters (KvDMR and H19 DMR) on chromosome 11p15 in placentae and neonatal blood for 20 control cases and 24 Small for Gestational Age (SGA) cases. We confirmed that, in normal human placenta, the H19 promoter is unmethylated. In contrast, most other human tissues show paternal methylation. In addition, we showed that the IGF2 DMR2, also paternally methylated in most human tissues, exhibits hypomethylation in placentae. However, in neonatal blood DNA, these two regions maintain the differential methylation status seen in most other tissues. Significantly, we have been able to demonstrate that placenta does maintain differential methylation at the imprinting control regions H19 DMR and KvDMR. Of note, in one SGA placenta, we found a methylation alteration at the H19 DMR and concomitant biallelic expression of the H19 gene, suggesting that loss of imprinting at H19 is one cause of poor fetal growth in humans. Of particular interest, we demonstrated also a decrease in IGF2 mRNA levels in all SGA placentae and showed that the decrease is, in most cases, independent of H19 regulation.     

Combretastatin A-4 disodium phosphate and low dose gamma irradiation suppress hepatocellular carcinoma by downregulating ROCK1 and VEGF gene expression

Molecular Biology Reports - Hepatocellular carcinoma (HCC) is a tough opponent. HCC contributes to 14.8% of all cancer mortality in Egypt. There are many choices for management of HCC; however...     

Development of Meloidogyne incognita Inhibited by Digtaria decumbens cv. Pangola

Population densities of the root-knot nematode, Meloidogyne incognita, were lower after 90 days in soil planted to digitgrass (Digitaria decumbens cv. Pangola) than in soil left fallow or planted to tomato. Roots of tomato seedlings interplanted with Pangola digitgrass were less galled than were roots of tomato seedlings planted alone. Fewer second stage larvae invaded roots of Pangola digitgrass than tomato and those that entered the grass roots failed to develop beyond the late second stage.     

Suppression of subtelomeric VSG switching by Trypanosoma brucei TRF requires its TTAGGG repeat-binding activity

Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, in the bloodstream of its mammalian host to evade the host immune response. VSGs are expressed exclusively from subtelomeric loci, and we have previously shown that telomere proteins TbTIF2 and TbRAP1 play important roles in VSG switching and VSG silencing regulation, respectively. We now discover that the telomere duplex DNA-binding factor, TbTRF, also plays a critical role in VSG switching regulation, as a transient depletion of TbTRF leads to significantly more VSG switching events. We solved the NMR structure of the DNA-binding Myb domain of TbTRF, which folds into a canonical helix-loop-helix structure that is conserved to the Myb domains of mammalian TRF proteins. The TbTRF Myb domain tolerates well the bulky J base in T. brucei telomere DNA, and the DNA-binding affinity of TbTRF is not affected by the presence of J both in vitro and in vivo. In addition, we find that point mutations in TbTRF Myb that significantly reduced its in vivo telomere DNA-binding affinity also led to significantly increased VSG switching frequencies, indicating that the telomere DNA-binding activity is critical for TbTRF''s role in VSG switching regulation.