15 research outputs found
Expression of nodal signalling components in cycling human endometrium and in endometrial cancer
<p>Abstract</p> <p>Background</p> <p>The human endometrium is unique in its capacity to remodel constantly throughout adult reproductive life. Although the processes of tissue damage and breakdown in the endometrium have been well studied, little is known of how endometrial regeneration is achieved after menstruation. Nodal, a member of the transforming growth factor-beta superfamily, regulates the processes of pattern formation and differentiation that occur during early embryo development.</p> <p>Methods</p> <p>In this study, the expression of Nodal, Cripto (co-receptor) and Lefty A (antagonist) was examined by RT-PCR and immunohistochemistry across the menstrual cycle and in endometrial carcinomas.</p> <p>Results</p> <p>Nodal and Cripto were found to be expressed at high levels in both stromal and epithelial cells during the proliferative phase of the menstrual cycle. Although immunoreactivity for both proteins in surface and glandular epithelium was maintained at relatively steady-state levels across the cycle, their expression was significantly decreased within the stromal compartment by the mid-secretory phase. Lefty expression, as has previously been reported, was primarily restricted to glandular epithelium and surrounding stroma during the late secretory and menstrual phases. In line with recent studies that have shown that Nodal pathway activity is upregulated in many human cancers, we found that Nodal and Cripto immunoreactivity increased dramatically in the transition from histologic Grade 1 to histologic Grades 2 and 3 endometrial carcinomas. Strikingly, Lefty expression was low or absent in all cancer tissues.</p> <p>Conclusion</p> <p>The expression of Nodal in normal and malignant endometrial cells that lack Lefty strongly supports an important role for this embryonic morphogen in the tissue remodelling events that occur across the menstrual cycle and in tumourogenesis.</p
Biological activity and in vivo half-life of pro-activin A in male rats
Mature TGF-β proteins are used in vivo to promote bone growth, combat obesity, reverse fibrosis and pulmonary arterial hypertension, and as potential rejuvenation factors. However, the serum half-life of this family of growth factors is short (∼5 min), limiting their therapeutic potential. Because TGF-β proteins are normally secreted from cells with their prodomains attached, we considered whether these molecules could extend the in vivo half-life and activity of their respective growth factors. Using activin A as a model ligand, we initially modified the cleavage site between the pro- and mature domains to ensure complete processing of the activin A precursor. Co-immunoprecipitation studies confirmed mature activin A is secreted from cells in a non-covalent complex with its prodomain, however, the affinity of this interaction is not sufficient to suppress activin A in vitro biological activity. The plasma clearance profiles of purified pro- and mature activin A were determined over a 4 h period in adult male rats. Both activin forms demonstrated a two-phase decay, with the half-life of pro-activin A (t1/2 fast = 12.5 min, slow = 31.0 min) being greater than that of mature activin A (t1/2 fast = 5.5 min, slow = 20.3 min). Both pro- and mature activin A induced significant increases in serum follicle stimulating hormone levels after 4 h, but no differences were observed in the relative in vivo bioactivities of the two activin isoforms. Increased serum half-life of activin A in the presence of its prodomain identifies a new means to increase the therapeutic effectiveness of TGF-β proteins
Virtual High-Throughput Screening To Identify Novel Activin Antagonists
Activin belongs to the TGFβ
superfamily, which is associated
with several disease conditions, including cancer-related cachexia,
preterm labor with delivery, and osteoporosis. Targeting activin and
its related signaling pathways holds promise as a therapeutic approach
to these diseases. A small-molecule ligand-binding groove was identified
in the interface between the two activin βA subunits and was
used for a virtual high-throughput in silico screening of the ZINC
database to identify hits. Thirty-nine compounds without significant
toxicity were tested in two well-established activin assays: FSHβ
transcription and HepG2 cell apoptosis. This screening workflow resulted
in two lead compounds: NUCC-474 and NUCC-555. These potential activin
antagonists were then shown to inhibit activin A-mediated cell proliferation
in ex vivo ovary cultures. In vivo testing showed that our most potent
compound (NUCC-555) caused a dose-dependent decrease in FSH levels
in ovariectomized mice. The Blitz competition binding assay confirmed
target binding of NUCC-555 to the activin A:ActRII that disrupts the
activin A:ActRII complex’s binding with ALK4-ECD-Fc in a dose-dependent
manner. The NUCC-555 also specifically binds to activin A compared
with other TGFβ superfamily member myostatin (GDF8). These data
demonstrate a new in silico-based strategy for identifying small-molecule
activin antagonists. Our approach is the first to identify a first-in-class
small-molecule antagonist of activin binding to ALK4, which opens
a completely new approach to inhibiting the activity of TGFβ
receptor superfamily members. in addition, the lead compound can serve
as a starting point for lead optimization toward the goal of a compound
that may be effective in activin-mediated diseases
Virtual High-Throughput Screening To Identify Novel Activin Antagonists
Activin belongs to the TGFβ
superfamily, which is associated
with several disease conditions, including cancer-related cachexia,
preterm labor with delivery, and osteoporosis. Targeting activin and
its related signaling pathways holds promise as a therapeutic approach
to these diseases. A small-molecule ligand-binding groove was identified
in the interface between the two activin βA subunits and was
used for a virtual high-throughput in silico screening of the ZINC
database to identify hits. Thirty-nine compounds without significant
toxicity were tested in two well-established activin assays: FSHβ
transcription and HepG2 cell apoptosis. This screening workflow resulted
in two lead compounds: NUCC-474 and NUCC-555. These potential activin
antagonists were then shown to inhibit activin A-mediated cell proliferation
in ex vivo ovary cultures. In vivo testing showed that our most potent
compound (NUCC-555) caused a dose-dependent decrease in FSH levels
in ovariectomized mice. The Blitz competition binding assay confirmed
target binding of NUCC-555 to the activin A:ActRII that disrupts the
activin A:ActRII complex’s binding with ALK4-ECD-Fc in a dose-dependent
manner. The NUCC-555 also specifically binds to activin A compared
with other TGFβ superfamily member myostatin (GDF8). These data
demonstrate a new in silico-based strategy for identifying small-molecule
activin antagonists. Our approach is the first to identify a first-in-class
small-molecule antagonist of activin binding to ALK4, which opens
a completely new approach to inhibiting the activity of TGFβ
receptor superfamily members. in addition, the lead compound can serve
as a starting point for lead optimization toward the goal of a compound
that may be effective in activin-mediated diseases
Comparative adherence of macitentan versus ambrisentan and bosentan in Australian patients with pulmonary arterial hypertension: a retrospective real-world database study
Bosentan, ambrisentan, and macitentan are endothelin receptor antagonists (ERAs), currently available in Australia for treatment of pulmonary arterial hypertension (PAH). This study assessed the comparative adherence of these ERAs for PAH in Australian patients. This retrospective, observational study used data for adults with PAH from the Services Australia 10% Pharmaceuticals Benefits Scheme (PBS) dataset (01/2006-10/2020). The primary outcome was treatment adherence (i.e. receiving ≥80% of ERA doses over 12 months). Secondary outcomes were time to treatment change (add-on or switch) and overall survival. The study included 436 patients who took bosentan (n = 200), ambrisentan (n = 69), or macitentan (n = 167). Treatment adherence was significantly greater in patients who received macitentan (65.3%) versus ambrisentan (56.5%) and bosentan (58.0%), with odds ratios (ORs; 95% CI) of 0.51 (0.30–0.88; p = 0.016) for bosentan versus macitentan and 0.48 (0.24–0.96; p = 0.037) for ambrisentan versus macitentan. The median time to treatment change was 47.2 and 43.4 months for bosentan and ambrisentan, respectively (not calculated for macitentan because of insufficient duration of data). Real-world data for Australian patients with PAH showed that treatment adherence for ERAs was suboptimal. Adherence was higher for macitentan compared with ambrisentan and bosentan.</p