PTEN deficiency promotes macrophage infiltration and hypersensitivity of prostate cancer to IAP antagonist/radiation combination therapy

PTEN loss is prognostic for patient relapse post-radiotherapy in prostate cancer (CaP). Infiltration of tumor-associated macrophages (TAMs) is associated with reduced disease-free survival following radical prostatectomy. However, the association between PTEN loss, TAM infiltration and radiotherapy response of CaP cells remains to be evaluated. Immunohistochemical and molecular analysis of surgically-resected Gleason 7 tumors confirmed that PTEN loss correlated with increased CXCL8 expression and macrophage infiltration. However PTEN status had no discernable correlation with expression of other inflammatory markers by CaP cells, including TNF-α. In vitro, exposure to conditioned media harvested from irradiated PTEN null CaP cells induced chemotaxis of macrophage-like THP-1 cells, a response partially attenuated by CXCL8 inhibition. Co-culture with THP-1 cells resulted in a modest reduction in the radio-sensitivity of DU145 cells. Cytokine profiling revealed constitutive secretion of TNF-α from CaP cells irrespective of PTEN status and IR-induced TNF-α secretion from THP-1 cells. THP-1-derived TNF-α increased NFκB pro-survival activity and elevated expression of anti-apoptotic proteins including cellular inhibitor of apoptosis protein-1 (cIAP-1) in CaP cells, which could be attenuated by pre-treatment with a TNF-α neutralizing antibody. Treatment with a novel IAP antagonist, AT-IAP, decreased basal and TNF-α-induced cIAP-1 expression in CaP cells, switched TNF-α signaling from pro-survival to pro-apoptotic and increased radiation sensitivity of CaP cells in co-culture with THP-1 cells. We conclude that targeting cIAP-1 can overcome apoptosis resistance of CaP cells and is an ideal approach to exploit high TNF-α signals within the TAM-rich microenvironment of PTEN-deficient CaP cells to enhance response to radiotherapy.

Osteoprotegerin Expression in the Dental Pulp

Objectives: The inflammatory response to pulpal injury or infection has major clinical significance. Osteoprotegerin (OPG) is a soluble decoy receptor for Receptor Activator of NF kappa B Ligand (RANKL), preventing ligand binding to its receptor (RANK), thus inhibiting clastic cell formation. The aim of the study is to investigate the expression of OPG in human dental pulp and the effects of inflammatory mediators. This study will specifically investigate the effects of Transforming Growth Factor Beta-1 (TGF-β1) and Interleukin 1-Beta (IL-1β) on the expression of OPG on pulp fibroblasts in vitro. Method: Five primary pulp fibroblast populations were obtained by explant culture of healthy pulp tissue. Triplicate cultures were grown to confluence in 12-well plates and stimulated for 48 hours with IL-1β (10ng/ml) or TGF-β1 (10ng/ml). The conditioned media was collected and OPG levels detected by ELISA (R+D Systems, UK). Results: All fibroblast populations produced quantifiable levels of OPG in a time-dependant fashion. IL-1β significantly increased the expression of OPG (p<0.05) in all cultures. In contrast, TGF-β1 had no significant effect on OPG expression levels. In addition, previous work in our laboratory demonstrated both TGF-β1 and IL-1β stimulated OPG expression by periodontal ligament fibroblasts. Conclusion: These data indicate that IL-1β-regulated expression of OPG by pulpal fibroblasts may mediate hard tissue turnover in the inflamed dental pulp.

Osteoprotegerin expression by periodontal ligament fibroblasts

Objectives: Receptor Activator of NF-kappaB ligand (RANKL), through binding to its receptor (RANK), plays an important role in osteoclast differentiation and activation. Conversely, osteoprotegerin (OPG), a decoy receptor for RANKL, inhibits osteoclastogenesis and subsequent bone turnover. Little is known about the role of resident periodontal ligament fibroblasts in regulating bone turnover. The aim of this study was to determine (i) if periodontal ligament fibroblasts produced OPG in vitro and (ii) the effects of IL-1b and TGF-b1 on OPG expression. Methods: Three human periodontal ligament fibroblast populations, developed by explant culture, were grown to confluence in 6-well plates in DMEM supplemented with 10% FCS. Cells were washed in HBSS and then cultured for an additional 48 hours in serum-free media supplemented with IL-1b or TGF-b1 at 10ng/ml. OPG expression levels in the conditioned medium were determined by ELISA (R&D Systems, UK) and confirmed by Western blot. Results: All three fibroblast strains produced quantifiable levels of OPG. Both IL-1b and, to a lesser extent, TGF-b1 significantly stimulated OPG expression in all fibroblast strains (p<0.05). Pre-incubation of samples with N-glycosidase F prior to Western blots indicated glycosylation of expressed OPG. Conclusions: These data indicate that periodontal ligament fibroblasts can regulate osteoclast activation via the RANK/RANKL signalling pathway. These fibroblasts may play an important role in regulating bone turnover both in periodontal disease and orthodontic tooth movement.

MRZ-99030 – a novel modulator of Aβ aggregation: II – reversal of Aβ oligomer-induced deficits in long-term potentiation (LTP) and cognitive performance in rats and mice.

β-amyloid1-42 (Aβ1-42) is a major endogenous pathogen underlying the aetiology of Alzheimer's disease (AD). Recent evidence indicates that soluble Aβ oligomers, rather than plaques, are the major cause of synaptic dysfunction and neurodegeneration. Small molecules that suppress Aβ aggregation, reduce oligomer stability or promote off-pathway non-toxic oligomerization represent a promising alternative strategy for neuroprotection in AD. MRZ-99030 was recently identified as a dipeptide that modulates Aβ1-42 aggregation by triggering a non-amyloidogenic aggregation pathway, thereby reducing the amount of intermediate toxic soluble oligomeric Aβ species. The present study evaluated the relevance of these promising results with MRZ-99030 under pathophysiological conditions i.e. against the synaptotoxic effects of Aβ oligomers on hippocampal long term potentiation (LTP) and two different memory tasks. Aβ1-42 interferes with the glutamatergic system and with neuronal Ca2+ signalling and abolishes the induction of LTP. Here we demonstrate that MRZ-99030 (100–500 nM) at a 10:1 stoichiometric excess to Aβ clearly reversed the synaptotoxic effects of Aβ1-42 oligomers on CA1-LTP in murine hippocampal slices. Co-application of MRZ-99030 also prevented the two-fold increase in resting Ca2+ levels in pyramidal neuron dendrites and spines triggered by Aβ1-42 oligomers. In anaesthetized rats, pre-administration of MRZ-99030 (50 mg/kg s.c.) protected against deficits in hippocampal LTP following i.c.v. injection of oligomeric Aβ1-42. Furthermore, similar treatment significantly ameliorated cognitive deficits in an object recognition task and under an alternating lever cyclic ratio schedule after the i.c.v. application of Aβ1-42 and 7PA2 conditioned medium, respectively. Altogether, these results demonstrate the potential therapeutic benefit of MRZ-99030 in AD.

Thermal environments and comfort in dementia friendly dwellings

This study follows on from a research project that developed guidelines for the Universal Design (UD) of Dementia Friendly Dwellings for People with Dementia, their Families and Carers. Research findings point to the need for thermal environments that support people with dementia and do not provoke stress, agitation or anxiety. Using semi-structured interviews and qualitative analysis of people with dementia this paper aims to provide insight into the questions of appropriate thermal environments. The qualitative analysis is supported by example simulated indoor environment studies that investigate comfort in common thermal environment provision scenarios in the homes of people with dementia. This paper focuses on the thermal environment, its impact on people with dementia, its therapeutic value, and its role in encouraging engagement in every day activity.
Findings from the interviews emphasize that control over their own internal environment is a priority for people with dementia. A strong preference for naturally or passively conditioned environments over mechanical conditioning is evident. Preferences are expressed for naturally ventilated environments enabling occupant instigated air movement. Repeated emphasis is placed on familiar elements including the fire and hot water bottle. Little desire is expressed for information feedback or technological displays.