Search

Objective: To investigate whether the Ala16Val polymorphism in the SOD2 gene, encoding for mitochondrial manganese superoxide dismutase (SOD), is associated with [1] infertility and [2] the pregnancy rate (PR) in IVF cycles. Design: Prospective case-control study. Setting: Public university and public university hospital. Patient(s): A total of 362 newborns (nonselected population) and 148 infertile women undergoing an IVF cycle, from which 44 became pregnant and 104 did not. Intervention(s): Blood samples extracted from the patients and newborn umbilical cord. Main Outcome Measure(s): Genotype and allele distribution of the Ala16Val polymorphism in the SOD2 gene using the tetra-primer amplification refractory mutation system–polymerase chain reaction (PCR). Result(s): The polymorphism distribution of the subfertile women was similar to that of a nonselected population. The SOD2 Ala allele frequency was 49% both in controls and IVF patients. In IVF population the Ala/Ala SOD2 genotype was 25%, with a 28% Val/Val homozygous. In contrast, the Ala/Ala genotype was associated with higher PRs in IVF (47% in Ala/Ala vs. 23% in no Ala/Ala). A multivariate logistic regression analysis revealed that the Ala/Ala genotype was an independent predictor of pregnancy (odds ratio [OR] = 3.29), followed by the number of transferred embryos (OR = 2.37) and age (OR = 0.84). Conclusion(s): The Ala/Ala SOD2 genotype is a significant independent predictor of the occurrence of pregnancy in IVF. Data also support a role for antioxidant defense, particularly in the mitochondria, in conception in IVF. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the serum oxidizability and antioxidant status in women undergoing an in vitro fertilization (IVF) cycle and to assess the possible relationship of the oxidizability indexes with the pregnancy rate.Design: Prospective, longitudinal study.Setting: Public university and public university hospital.Patient(s): Systematically recruited cohort of 125 women undergoing either IVF or intracytoplasmic sperm injection (ICSI).Intervention(s): Serum samples were collected before the beginning of the use of gonadotropins (basal) and the day of human chorionic gonadotropin (hCG) administration (final) during an IVF cycle.Main Outcome Measure(s): The Cu2+-induced serum oxidation in terms of the oxidation rate in the lag (Vlag) and propagation (Vmax) phases and the time at which the oxidation rate is maximal (tmax), and measurements of serum total antioxidant activity (TAA), tocopherol, hydrophilic antioxidants, malondialdehyde, and nitric oxide.Result(s): Albumin, urate, bilirubin, alpha-tocopherol and gamma-tocopherol, TAA, and tmax statistically significantly decreased after the IVF cycle. Conception cycles were associated with a serum more prone to oxidation compared with nonconception cycles. In multivariate logistic regression analysis, the difference (final-basal) of the oxidation index Vlag (OR 1.394) and the body mass index (OR 0.785) were independent predictors of pregnancy.Conclusion(s): Treatment with IVF induces the production of reactive oxygen species (ROS), which is reflected in a serum less protected against oxidation. The results also suggest a role for ROS in the occurrence of conception in IVF. [ABSTRACT FROM AUTHOR]

Simple Summary: E2F1 and E2F2 are highly expressed in many cancer types, but their contribution to malignancy is not well understood. Here we aimed to define the impact of E2F1/E2F2 deregulation in prostate cancer. We show that inhibition of E2F sensitizes prostate cancer cells to drug-induced replication stress and cell death. We found that E2F target genes involved in nucleotide biosynthesis contribute to maintaining genome stability in prostate cancer cells, but their enzymatic activity is insufficient to prevent replication stress after E2F1/E2F2 depletion. Instead, E2F1/E2F2 hinder premature CDK1 activation during S phase, which is key to ensure genome stability and viability of prostate cancer cells. From a therapeutic perspective, inhibiting E2F activity provokes catastrophic levels of replication stress and blunts xenograft growth in combination with drugs targeting nucleotide biosynthesis or DNA repair. Our results highlight the suitability of targeting E2F for the treatment of prostate cancer. E2F1/E2F2 expression correlates with malignancy in prostate cancer (PCa), but its functional significance remains unresolved. To define the mechanisms governed by E2F in PCa, we analyzed the contribution of E2F target genes to the control of genome integrity, and the impact of modulating E2F activity on PCa progression. We show that silencing or inhibiting E2F1/E2F2 induces DNA damage during S phase and potentiates 5-FU-induced replication stress and cellular toxicity. Inhibition of E2F downregulates the expression of E2F targets involved in nucleotide biosynthesis (TK1, DCK, TYMS), whose expression is upregulated by 5-FU. However, their enzymatic products failed to rescue DNA damage of E2F1/E2F2 knockdown cells, suggesting additional mechanisms for E2F function. Interestingly, targeting E2F1/E2F2 in PCa cells reduced WEE1 expression and resulted in premature CDK1 activation during S phase. Inhibition of CDK1/CDK2 prevented DNA damage induced by E2F loss, suggesting that E2F1/E2F2 safeguard genome integrity by restraining CDK1/CDK2 activity. Importantly, combined inhibition of E2F and ATR boosted replication stress and dramatically reduced tumorigenic capacity of PCa cells in xenografts. Collectively, inhibition of E2F in combination with drugs targeting nucleotide biosynthesis or DNA repair is a promising strategy to provoke catastrophic levels of replication stress that could be applied to PCa treatment. [ABSTRACT FROM AUTHOR]

Osteopontin (OPN), a senescence‐associated secretory phenotype factor, is increased in patients with nonalcoholic fatty liver disease (NAFLD). Cellular senescence has been associated with age‐dependent hepatosteatosis. Thus, we investigated the role of OPN in the age‐related hepatosteatosis. For this, human serum samples, animal models of aging, and cell lines in which senescence was induced were used. Metabolic fluxes, lipid, and protein concentration were determined. Among individuals with a normal liver, we observed a positive correlation between serum OPN levels and increasing age. This correlation with age, however, was absent in patients with NAFLD. In wild‐type (WT) mice, serum and liver OPN were increased at 10 months old (m) along with liver p53 levels and remained elevated at 20m. Markers of liver senescence increased in association with synthesis and concentration of triglycerides (TG) in 10m OPN‐deficient (KO) hepatocytes when compared to WT hepatocytes. These changes in senescence and lipid metabolism in 10m OPN‐KO mice liver were associated with the decrease of 78 kDa glucose‐regulated protein (GRP78), induction of ER stress, and the increase in fatty acid synthase and CD36 levels. OPN deficiency in senescent cells also diminished GRP78, the accumulation of intracellular TG, and the increase in CD36 levels. In 20m mice, OPN loss led to increased liver fibrosis. Finally, we showed that OPN expression in vitro and in vivo was regulated by p53. In conclusion, OPN deficiency leads to earlier cellular senescence, ER stress, and TG accumulation during aging. The p53‐OPN axis is required to inhibit the onset of age‐related hepatosteatosis. [ABSTRACT FROM AUTHOR]

Although Schwann cell myelin breakdown is the universal outcome of a remarkably wide range of conditions that cause disease or injury to peripheral nerves, the cellular and molecular mechanisms that make Schwann cell-mediated myelin digestion possible have not been established. We report that Schwann cells degrade myelin after injury by a novel form of selective autophagy, myelinophagy. Autophagy was up-regulated by myelinating Schwann cells after nerve injury, myelin debris was present in autophagosomes, and pharmacological and genetic inhibition of autophagy impaired myelin clearance. Myelinophagy was positively regulated by the Schwann cell JNK/c-Jun pathway, a central regulator of the Schwann cell reprogramming induced by nerve injury. We also present evidence that myelinophagy is defective in the injured central nervous system. These results reveal an important role for inductive autophagy during Wallerian degeneration, and point to potential mechanistic targets for accelerating myelin clearance and improving demyelinating disease. [ABSTRACT FROM AUTHOR]

Background: Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression. Methods: Primary cultures were established from human breast tumour and adjacent non-tumour tissue. Putative progenitor cell populations were isolated based on co-expression or concomitant absence of the epithelial and myoepithelial markers EPCAM and CALLA respectively. Results: Significant reductions in cellular senescence were observed in tumour versus non-tumour cultures, accompanied by a stepwise increase in proliferation:senescence ratios. A novel correlation between tumour aggressiveness and an imbalance of putative progenitor subpopulations was also observed. Specifically, an increased double-negative (DN) to double-positive (DP) ratio distinguished aggressive tumours of high grade, estrogen receptor-negativity or HER2-positivity. The DN:DP ratio was also higher in malignant MDA-MB-231 cells relative to non-tumourogenic MCF-10A cells. Ultrastructural analysis of the DN subpopulation in an invasive tumour culture revealed enrichment in lipofuscin bodies, markers of ageing or senescent cells. Conclusions: Our results suggest that an imbalance in tumour progenitor subpopulations imbalances the functional relationship [ABSTRACT FROM AUTHOR]

Chronic hepatitis B is a major cause of liver-related death worldwide. Interleukin-12 (IL-12) induction accompanies viral clearance in chronic hepatitis B virus infection. Here, we tested the therapeutic potential of IL-12 gene therapy in woodchucks chronically infected with woodchuck hepatitis virus (WHV), an infection that closely resembles chronic hepatitis B. The woodchucks were treated by intrahepatic injection of a helper-dependent adenoviral vector encoding IL-12 under the control of a liver-specific RU486-responsive promoter. All woodchucks with viral loads below 1010 viral genomes (vg)/ml showed a marked and sustained reduction of viremia that was accompanied by a reduction in hepatic WHV DNA, a loss of e antigen and surface antigen, and improved liver histology. In contrast, none of the woodchucks with higher viremia levels responded to therapy. The antiviral effect was associated with the induction of T-cell immunity against viral antigens and a reduction of hepatic expression of Foxp3 in the responsive animals. Studies were performed in vitro to elucidate the resistance to therapy in highly viremic woodchucks. These studies showed that lymphocytes from healthy woodchucks or from animals with low viremia levels produced gamma interferon (IFN-γ) upon IL-12 stimulation, while lymphocytes from woodchucks with high viremia failed to upregulate IFN-γ in response to IL-12. In conclusion, IL-12-based gene therapy is an efficient approach to treat chronic hepadnavirus infection in woodchucks with viral loads below 1010 vg/ml. Interestingly, this therapy is able to break immunological tolerance to viral antigens in chronic WHV carriers. [ABSTRACT FROM AUTHOR]