Chemotherapy enhances TNF-related apoptosis-inducing ligand DISC assembly in HT29 human colon cancer cells

Cytokines such as Fas-ligand (Fas-L) and Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) can induce human colon cancer cell apoptosis through engagement of their death domain receptors. All the cancer cells are not sensitive to these cytokines. We have shown recently that low doses of cytotoxic drugs could restore TRAIL-induced cell death in resistant colon cancer cell lines. The present work further explores the death pathway triggered by the cytotoxic drug/TRAIL combination in HT-29 colon cancer cells (www.alexis-corp.com). Clinically relevant concentrations of cisplatin, doxorubicin and 5-fluorouracil synergize with TRAIL to trigger HT-29 cell death. Activation of this pathway leads to apoptosis that involves both caspases and the mitochondria. An increased recruitment of Fas-associated death domain (FADD) and procaspase-8 to the TRAIL-induced death-inducing signaling complex (DISC) was shown in cells exposed to anticancer drugs. Following caspase-8 activation at the DISC level, the mitochondria-dependent death pathway is activated, as demonstrated by the cleavage of Bid, the dissipation of DeltaPsi(m), the release of mitochondrial proteins in the cytosol and the inhibitory effect of Bcl-2 expression. Importantly, besides mitochondrial potentiation, we show here that cytotoxic drugs sensitize HT-29 colon cancer cells to TRAIL-induced cell death by enhancing FADD and procaspase-8 recruitment to the DISC, a novel mechanism whose efficacy could depend partly on Bcl-2 expression level

Plasma phospholipid transfer protein (PLTP) as an emerging determinant of the adaptive immune response

International audienc

Motivations and personality characteristics of candidate sperm and oocyte donors according to parenthood status: a national study from the French CECOS network

International audienceAbstract STUDY QUESTION In a non-commercial national gamete donation programme, do the motivations and personality characteristics of candidate sperm and oocyte donors differ according to their parenthood status? SUMMARY ANSWER Moderate differences exist between non-parent and parent candidate donors in motivations for gamete donation and representations as well as in personality characteristics. WHAT IS KNOWN ALREADY Several studies have analysed the motivations and experiences of oocyte or sperm donors, but mainly in countries where gamete donation is a commercial transaction, and very few studies have reported results of personality traits using personality inventory tests. No study has specifically investigated the motivations and personality characteristics of candidate gamete donors according to parenthood status. STUDY DESIGN, SIZE, DURATION A prospective study was carried out including 1021 candidate donors from 21 centres (in university hospitals) of the national sperm and egg banking network in France between November 2016 and December 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS In total, 1021 candidate gamete donors were included in the study. During their first visit, male (n = 488) and female candidate donors (n = 533) completed a questionnaire on sociodemographic characteristics, their motivations for donation and their representations of donation, infertility and family. Secondly, a NEO Personality Inventory (NEO-PI-R) exploring the Big Five personality traits was completed online. Results were compared between parent and non-parent candidate donors. MAIN RESULTS AND THE ROLE OF CHANCE Altruistic values were the principal motive for donation irrespective of parenthood status. Reassurance about their fertility or preservation of sperm for future use was more often reported in non-parent than in parent candidate donors. With regard to representation of gamete donation or of the family, independently of their parenthood status, candidate donors more frequently selected social rather than biological representations. Mean personality characteristics were in the normal range. Non-parent candidate donors had higher scores on openness and depression than parents, while parent candidate donors appeared more social than non-parents. LIMITATIONS, REASONS FOR CAUTION The personality characteristics inventory was not completed by all candidate donors included in the study. However, family status did not differ between the two groups (NEO-PI-R completed (n = 525) or not), while the group who completed the NEO-PI-R had a higher educational level. This national study was performed in a country where gamete donation is subject to strict legislation. WIDER IMPLICATIONS OF THE FINDINGS In a global context where reproductive medicine is commercialized and gamete donor resources are limited, this study found that altruism and social representations of gamete donation and family are the main motivations for gamete donation in a country which prohibits financial incentive. These findings are relevant for health policy and for gamete donation information campaigns. STUDY FUNDING/COMPETING INTEREST(S) Grant from the Agence de la Biomédecine, France. The authors have nothing to disclose related to this study. TRIAL REGISTRATION NUMBER N/A

Increased Amyloid-β Peptide-Induced Memory Deficits in Phospholipid Transfer Protein (PLTP) Gene Knockout Mice

Oxidative stress is recognized as one of the earliest and most intense pathological processes in Alzheimer's disease (AD), and the antioxidant vitamin E has been shown to efficiently prevent amyloid plaque formation and neurodegeneration. Plasma phospholipid transfer protein (PLTP) has a major role in vitamin E transfers in vivo, and PLTP deficiency in mice is associated with reduced brain vitamin E levels. To determine the impact of PLTP on amyloid pathology in vivo, we analyzed the vulnerability of PLTP-deficient (PLTP-KO) mice to the toxic effects induced by intracerebroventricular injection of oligomeric amyloid-β(25–35) (Aβ(25–35)) peptide, a non-transgenic model of AD. Under basal conditions, PLTP-KO mice showed increased cerebral oxidative stress, increased brain Aβ(1–42) levels, and a lower expression of the synaptic function marker synaptophysin, as compared with wild-type mice. This PLTP-KO phenotype was associated with increased memory impairment 1 week after Aβ(25–35) peptide injection. Restoration of brain vitamin E levels in PLTP-KO mice through a chronic dietary supplementation prevented Aβ(25–35)-induced memory deficits and reduced cerebral oxidative stress and toxicity. We conclude that PLTP, through its ability to deliver vitamin E to the brain, constitutes an endogenous neuroprotective agent. Increasing PLTP activity may offer a new way to develop neuroprotective therapies

Nuclear receptor profiling of ovarian granulosa cell tumors

Granulosa cell tumors of the ovary (GCT) represent ~5% of malignant ovarian tumors. The adult form is defined by a mutation in the FOXL2 gene. GCT exhibit many of the features of normal proliferating granulosa cells. We have profiled the expression of the 48 human nuclear receptors (NR) by quantitative RT-PCR in a panel of GCT and in two GCT-derived cell lines, COV434 and KGN. The highest level of expression is seen for COUP-TF2 with abundant expression of PPARγ, SF-1, and TR-α. Estrogen receptor (ER)-β is the most abundant of the steroid receptors with relatively high expression also of AR, ER-α, and PR. The concordance of expression for each NR across the tumors is remarkably high with same discordance between the cell lines and the tumors, particularly the COV434 line. No significant differences were observed with respect to tumor stage for NR expression. These findings provide a full profile of NR expression in GCT which will enable full characterization of their roles and potential as therapeutic targets