No abstract

Clinical studies have indicated that the stent-eluting drugs sirolimus and paclitaxel impact restenosis; however, it is still elusive how these drugs affect the vascular endothelium at the molecular and cellular levels. The purpose of this study was to determine whether sirolimus and paclitaxel induce molecular and cellular alterations in the vascular endothelium. Endothelial regrowth was assessed in human aortic endothelial cells and rat aortic endothelium. Molecular and cellular alterations were analyzed in human aortic endothelial cells by Western blot analysis, transmission electron microscopy, and immunofluorescence staining. Green fluorescent protein-LC3 mice were used to analyze autophagic endothelium. Here, we show that sirolimus and paclitaxel differentially induce self-digesting autophagy in vascular endothelial cells with changes in expression of LC3B, p53, and Bcl-2, considerably suppressing re-endothelialization and revascularization. These results suggest that phenotypic alteration in the endothelium by sirolimus or paclitaxel might affect the rates of late stent thrombosis, myocardial infarction, and mortality.

Lymphatic metastasis of human malignant adenocarcinomas is a critical determinant of prognosis. Lymphangiogenesis, the growth of lymphatic vessels, is closely involved in lymphatic metastasis. However, the mechanisms of tumor lymphangiogenesis are not clearly understood. In a previous study, we showed that human gastric cancer MKN45 cells organize neighboring lymphatic vessels via recruitment of bone marrow-derived lymphatic endothelial progenitor cells in a nude mouse xenograft model. The present results also indicated that human colorectal cancer LS174T and breast cancer SK-BR-3 cells promoted lymphangiogenesis as well as the recruitment of lymphatic endothelial progenitor cells from bone marrow. Among growth factors, which are reported to be involved in lymphangiogenesis, only vascular endothelial growth factor (VEGF)-A was extensively secreted by these three types of adenocarcinoma cells in culture. The well-characterized lymphangiogenic factors VEGF-C and VEGF-D in the culture medium of these three types of adenocarcinoma cells were below the detectable levels in ELISA assay. Secretion of epidermal growth factor (EGF) and hepatocyte growth factor (HGF) was not detected. In in vitro culture assay, VEGF-A directly induced the differentiation of bone marrow mononuclear cells into LYVE-1-positive lymphatic endothelial lineage cells. These data collectively suggest the possibility that VEGF-A-rich human adenocarcinomas induce tumor lymphangiogenesis via recruitment of lymphangiogenic endothelial progenitor cells from bone marrow.

These findings of this study suggest that human gastric adenocarcinoma induces tumor lymphangiogenesis via recruitment of LEPC from BM.

Objective: Standard treatment for progressive gastric cancer with bleeding includes hemostatic radiotherapy (RT); however, the only prospective study using a fixed dose with fractions during hemostatic RT did not introduce re-irradiation. Therefore, we determined the utility of RT including re-irradiation for gastric cancer. Methods: In this study, 31 patients with gastric cancer and bleeding were treated with an initial dose of 20 Gy/5 fractions for the whole stomach and a salvage dose of 15 Gy/5 fractions for the partial stomach. Patients achieving hemostasis, defined as a stable hemoglobin level within 30 days following irradiation, were considered responders, whereas those with no cessation of bleeding and those with re-bleeding within 30 days of irradiation were considered non-responders. We evaluated response rate, disease-free survival, overall survival (OS), re-irradiation, and adverse events (AEs). Results: The response rate of initial RT was 80% (25/31). 6 of the 25 patients underwent re-irradiation, and all 6 were responders (100%). The median OS was significantly different among the entire cohort and one-time irradiation and re-irradiation groups (91, 76, and 112 days, respectively). No AEs of grade ≥3 were observed. Initial low-dose RT followed by reirradiation was effective in reducing AEs and did not cause any further AEs. Conclusion: Hemostatic RT was an effective approach with low toxicity, and re-irradiation was effective and tolerable, with no patients developing severe AEs. Further, randomized controlled studies are warranted to determine the ideal dose and number of fractions for initial RT in patients with gastric cancer and bleeding. Advances in knowledge: In this prospective study on hemostatic radiotherapy for gastric cancer, the response rate was 80% using a fixed dose of 20 Gy/5 fractions and the salvage dose of 15 Gy for re-bleeding was effective. Future comparative studies should include other doses with 20 Gy as a control.