5 research outputs found
Additional file 2: of Safety and tolerability of quizartinib, a FLT3 inhibitor, in advanced solid tumors: a phase 1 dose-escalation trial
Most common (reported in ≥2 patients) treatment-emergent adverse events (safety population). (DOCX 18 kb
Nicotinamide Inhibits Vasculogenic Mimicry, an Alternative Vascularization Pathway Observed in Highly Aggressive Melanoma
<div><p>Vasculogenic mimicry (VM) describes functional vascular channels composed only of tumor cells and its presence predicts poor prognosis in melanoma patients. Inhibition of this alternative vascularization pathway might be of clinical importance, especially as several anti-angiogenic therapies targeting endothelial cells are largely ineffective in melanoma. We show the presence of VM structures histologically in a series of human melanoma lesions and demonstrate that cell cultures derived from these lesions form tubes in 3D cultures <i>ex vivo</i>. We tested the ability of nicotinamide, the amide form of vitamin B3 (niacin), which acts as an epigenetic gene regulator through unique cellular pathways, to modify VM. Nicotinamide effectively inhibited the formation of VM structures and destroyed already formed ones, in a dose-dependent manner. Remarkably, VM formation capacity remained suppressed even one month after the complete withdrawal of Nicotimamid. The inhibitory effect of nicotinamide on VM formation could be at least partially explained by a nicotinamide-driven downregulation of vascular endothelial cadherin (VE-Cadherin), which is known to have a central role in VM. Further major changes in the expression profile of hundreds of genes, most of them clustered in biologically-relevant clusters, were observed. In addition, nicotinamide significantly inhibited melanoma cell proliferation, but had an opposite effect on their invasion capacity. Cell cycle analysis indicated moderate changes in apoptotic indices. Therefore, nicotinamide could be further used to unravel new biological mechanisms that drive VM and tumor progression. Targeting VM, especially in combination with anti-angiogenic strategies, is expected to be synergistic and might yield substantial anti neoplastic effects in a variety of malignancies.</p> </div
Nicotinamide (NA) abrogates vasculogenic mimicry.
<p>(A) NA was added 24 h after capillary-like structures were developed (destruction of VM formation). NA was added in concentrations of 5 mM and 20 mM as indicated for additional 24 h. Afterwards, microphotographs were captured; (B) HAG was cultured in the presence of NA (same concentrations as A) for 1 month (prevention of VM formation). Subsequently, the treated cells were cultured on Matrigel to enable VM formation. The images were captured after 24 h; (C). Prolonged inhibition of VM formation by NA treatment. The cells were incubated with NA for 72 h, re-plated without NA for 1 month, followed by VM testing. Microphotographs were capture 24 h after plating. Each picture (A–C) was derived from one representative experiment out of three performed. Each experiment was performed in duplicates; (D) Tube formation was quantified using the ImageJ analyze skeleton PlugIn. Figure showed the average length calculated for each sample out of all image captured in all three experiments performed. Statistical significant was tested with 2-tailed paired <i>t-test</i>. (E) Effect of NA on VE-cadherin expression in the HAG cells cultured for 1 month in the presence of NA. (F) Effect of NA on VEGF-A expression in the HAG cells cultured for 1 month in the presence of NA. Black thin line histogram represents cells stained with isotype control; other histograms represent cells treated either with vehicle or various NA concentrations, as indicated in the figure. Figure shows representative experiments out of three performed.</p
Characterization of vessel with PAS-CD31 dual staining (endothelial or vessel like channels – VM) in paraffin sections of melanoma patients.
<p>(A) PAS-positive VM channels with no endothelial marker CD31 staining, black arrows indicate VM channels; (B) PAS-negative patterns and CD31-positive staining; red arrows indicate endothelial channels; (C) PAS-positive and CD31-positive channels; (D) a summary of microscopic vessels observed. Microscopic evaluation was done blindly by two pathologists. The data represents average values as seen in 10 high power fields per sample.</p
Vasculogenic mimicry characteristics.
<p>nd = not determined.</p>*<p>CD31-PAS double-staining calculate as N<sub>VM structures</sub>/(N<sub>VM structures</sub>+N<sub>CD31-positive structures</sub>) ×100.</p>**<p>Percentage of VE-cadherin expression was determined by FACS analysis.</p