Single and combined effects of αvβ3- and α5β1-integrins on capillary tube formation in a human fibrinous matrix

The fibrinous exudate of a wound or tumor stroma facilitates angiogenesis. We studied the involvement of RGD-binding integrins during tube formation in human plasma-derived fibrin clots and human purified fibrin matrices. Capillary-like tube formation by human microvascular endothelial cells in a 3D plasma-derived fibrinous matrix was induced by FGF-2 and TNF-α and depended largely on cell-bound u-PA and plasmin activities. While tube formation was minimally affected by the addition of either the αvβ3-integrin inhibiting mAb LM609 or the α5-integrin inhibiting mAb IIA1, the general RGD-antagonist echistatin completely inhibited this process. Remarkably, when αvβ3- and α5β1-integrins were inhibited simultaneously, tube formation was reduced by 78%. It was accompanied by a 44% reduction of u-PA antigen accumulation and 41% less production of fibrin degradation products. αvβ5-integrin-blocking antibodies further enhanced the inhibition by mAb LM609 and mAb IIA1 to 94%, but had no effect by themselves. αv-specific cRGD only inhibited angiogenesis when α5β1-integrin was simultaneously blocked. Endostatin mimicked the effect of α5β1-integrin and inhibited tube formation only in the presence of LM609 or cRGD (73 and 80%, respectively). Comparable results were obtained when purified fibrin matrices were used instead of the plasma-derived fibrinous matrices. These data show that blocking of tube formation in a fibrinous exudate requires the simultaneous inhibition of αvβ3- and α5β1-integrins. This may bear impact on attempts to influence angiogenesis in a fibrinous environment

In Vivo Evaluation of Indium-111-Labeled 800CW as a Necrosis-Avid Contrast Agent.

Current clinical measurements for tumor treatment efficiency rely often on changes in tumor volume measured as shrinkage by CT or MRI, which become apparent after multiple lines of treatment and pose a physical and psychological burden on the patient. Detection of therapy-induced cell death in the tumor can be a fast measure for treatment efficiency. However, there are no reliable clinical tools for detection of tumor necrosis. Previously, we studied the necrosis avidity of cyanine-based fluorescent dyes, which suffered long circulation times before tumor necrosis could be imaged due to low hydrophilicity. We now present the application of radiolabeled 800CW, a commercially available cyanine with high hydrophilicity, to image tumor necrosis in a mouse model. We conjugated 800CW to DOTA via a PEG linker, for labeling with single-photon emission-computed tomography isotope indium-111, yielding [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW. We then investigated specific [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW uptake by dead cells in vitro, using both fluorescence and radioactivity as detection modalities. Finally, we investigated [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW uptake into necrotic tumor regions of a 4T1 breast tumor model in mice. We successfully prepared a precursor and developed a reliable procedure for labeling 800CW with indium-111. We detected specific [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW uptake by dead cells, using both fluorescence and radioactivity. Albeit with a tumor uptake of only 0.37%ID/g at 6 h post injection, we were able to image tumor necrosis with a tumor to background ratio of 7:4. Fluorescence and radioactivity in cryosections from the dissected tumors were colocalized with tumor necrosis, confirmed by TUNEL staining. [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW can be used to image tumor necrosis in vitro and in vivo. Further research will elucidate the application of [ <sup>111</sup> In]In-DOTA-PEG <sub>4</sub> -800CW or other radiolabeled hydrophilic cyanines for the detection of necrosis caused by chemotherapy or other anti-cancer therapies. This can provide valuable prognostic information in treatment of solid tumors

pH-Channeling in Cancer: How pH-Dependence of Cation Channels Shapes Cancer Pathophysiology.

Tissue acidosis plays a pivotal role in tumor progression: in particular, interstitial acidosis promotes tumor cell invasion, and is a major contributor to the dysregulation of tumor immunity and tumor stromal cells. The cell membrane and integral membrane proteins commonly act as important sensors and transducers of altered pH. Cell adhesion molecules and cation channels are prominent membrane proteins, the majority of which is regulated by protons. The pathophysiological consequences of proton-sensitive ion channel function in cancer, however, are scarcely considered in the literature. Thus, the main focus of this review is to highlight possible events in tumor progression and tumor immunity where the pH sensitivity of cation channels could be of great importance

Peptide based amphiphiles

Contains fulltext : 13849.pdf (publisher's version ) (Open Access

Long-term outcome and chest pain in patients with true versus non-true bifurcation lesions treated with second-generation drug-eluting stents in the TWENTE trial

The objective of this study is to assess 3-year clinical outcome of patients with true bifurcation lesions (TBLs) versus non-true bifurcation lesions (non-TBLs) following treatment with second-generation drug-eluting stents (DES). TBLs are characterized by the obstruction of both main vessel and side-branch. Limited data are available on long-term clinical outcome following TBL treatment with newer-generation DES. We performed an explorative sub-study of the randomized TWENTE trial among 287 patients who had bifurcated target lesions with side-branches ≥2.0 mm. Patients were categorized into TBL (Medina classes: 1.1.1; 1.0.1; 0.1.1) versus non-TBL to compare long-term clinical outcome. A total of 116 (40.4 %) patients had TBL, while 171 (59.6 %) had non-TBL only. Target-lesion revascularization rates were similar (3.5 vs. 3.5 %; p = 1.0), and definite-or-probable stent thrombosis rates were low (both <1.0 %). The target-vessel myocardial infarction (MI) rate was 11.3 versus 5.3 % (p = 0.06), mostly driven by (periprocedural) MI ≤48 h from PCI. All-cause mortality and cardiac death rates were 8.7 versus 3.5 % (p = 0.06) and 3.5 versus 1.2 % (p = 0.22), respectively. The 3-year major adverse cardiac event rate for patients with TBL versus non-TBL was 20.0 versus 11.7 % (p = 0.05). At 1-, 2-, and 3-year follow-up, 6.5, 13.0, and 11.0 % of patients reported chest pain at less than or equal moderate physical effort, respectively, without any between-group difference. Patients treated with second-generation DES for TBL had somewhat higher adverse event rates than patients with non-TBL, but dissimilarities did not reach statistical significance. Up to 3-year follow-up, the vast majority of patients of both groups remained free from chest pain

Applying HDACis to increase SSTR2 expression and radiolabeled DOTA-TATE uptake:from cells to mice

Aims: The aim of our study was to determine the effect of histone deacetylase (HDAC) inhibitors (HDACis) on somatostatin type-2 receptor (SSTR2) expression and [111In]In-/[177Lu]Lu-DOTA-TATE uptake in vitro and in vivo. Materials and methods: The human cell lines NCI-H69 (small-cell lung carcinoma) and BON-1 (pancreatic neuroendocrine tumor) were treated with HDACis (i.e. entinostat, mocetinostat (MOC), LMK-235, CI-994 or panobinostat (PAN)), and SSTR2 mRNA expression levels and [111In]In-DOTA-TATE uptake were measured. Furthermore, vehicle- and HDACi-treated NCI-H69 and BON-1 tumor-bearing mice were injected with radiolabeled DOTA-TATE followed by biodistribution studies. Additionally, SSTR2 and HDAC mRNA expression of xenografts, and of NCI-H69, BON-1, NCI-H727 (human pulmonary carcinoid) and GOT1 (human midgut neuroendocrine tumor) cells were determined. Key findings: HDACi treatment resulted in the desired effects in vitro. However, no significant increase in tumoral DOTA-TATE uptake was observed after HDACi treatment in NCI-H69 tumor-bearing animals, whereas tumoral SSTR2 mRNA and/or protein expression levels were significantly upregulated after treatment with MOC, CI-994 and PAN, i.e. a maximum of 2.1- and 1.3-fold, respectively. Analysis of PAN-treated BON-1 xenografts solely demonstrated increased SSTR2 mRNA expression levels. Comparison of HDACs and SSTR2 expression in BON-1 and NCI-H69 xenografts showed a significantly higher expression of 6/11 HDACs in BON-1 xenografts. Of these HDACs, a significant inverse correlation was found between HDAC3 and SSTR2 expression (Pearson r = −0.92) in the studied cell lines. Significance: To conclude, tumoral uptake levels of radiolabeled DOTA-TATE were not enhanced after HDACi treatment in vivo, but, depending on the applied inhibitor, increased SSTR2 expression levels were observed.</p