[Human recombinant erythropoietin-alpha increases the efficacy of irradiation in preclinical model]

According to recent data erythropoietin receptor (EPOR) is expressed not only by bone marrow erythroid progenitors but by endothelial- and cancer cells and it was suggested that erythropoietin (EPO) may affect their functions as well. We have analyzed the effects of recombinant human erythropoietin-alpha (rHuEPOalpha) on radiation sensitivity of EPOR+ human epidermoid carcinoma (A431) xenograft model. In vivo rHuEPOalpha treatment was started after tumor cell inoculation into SCID mice. 5 Gy irradiation was performed on day 14, the effect of which was measured on day 22. Hemoglobin level, tumor-associated microvessels and HIF-1alpha expression of the xenograft were monitored during the experiment. rHuEPOalpha administration prevented the development of tumor-induced anemia of SCID mice and reduced the level of HIF-1alpha expression of the xenograft tumor without affecting tumor growth. We have found that rHuEPOalpha treatment significantly increased the efficacy of antitumor effect of irradiation which was partly mediated by complex effects on tumor-associated microvessels. In vitro rHuEPOalpha did not affect proliferation of A431 cells but enhanced the antiproliferative and proapoptotic effects of irradiation. We concluded that rHuEPOalpha administration positively modulated the antitumoral effects of irradiation at least by two pathways, decreasing systemic hypoxia resulting in decreased tumoral HIF-1alpha expression and enhancing direct effects on tumor-associated microvessels.

Recombinant human erythropoietin alpha targets intratumoral blood vessels, improving chemotherapy in human xenograft models

Recombinant human erythropoietin (rHuEPO) is widely used for correction of hemoglobin level in cancer patients. However, apart from hematopoiesis, rHuEPO reportedly has an effect on endothelial cells. We describe here how rHuEPOalpha can modulate tumor vasculature in human squamous cell (A431) and colorectal carcinoma (HT25) xenograft models. In vivo rHuEPO treatment of xenografts at human-equivalent dose significantly increased the proliferation index of the tumor-associated endothelial cells and the size of CD31-positive intratumoral blood vessels, whereas the pericyte coverage became fragmented. Moreover, rHuEPO administration resulted in decreased expression of vascular endothelial growth factor both by cancer cells and tumor stroma, measured by quantitative PCR. Due to the morphologic alterations in tumoral microvessels, DNA-binding agents (Hoechst and Doxorubicin) labeled significantly larger areas in the tumor mass. Furthermore, rHuEPO treatment led to a significantly improved efficacy of 5-fluorouracil (5-FU) chemotherapy in the case of both tumor xenografts. Meanwhile, rHuEPO had no effect on the in vitro proliferation of erythropoietin receptor-positive tumor cells, and did not interfere with the effects of 5-FU either. These data reveal a new effect of rHuEPO administration: remodeling tumoral microvessels, suppressing vascular endothelial growth factor expression, thereby augmenting antitumor effects of a cancer drug, 5-FU, even in erythropoietin receptor-positive human cancer xenografts.

[Heparin inhibits metastatization of experimental melanoma]

Heparin treatment, at human equivalent doses, modulates coagulation parameters in mice similarly to the human situation. Heparins were tested in various melanoma metastasis models for their antimetastatic activity. Heparins were active against melanoma metastasis without influencing the primary tumor. Tumor cell-induced platelet aggregation was not the primary target of heparins, since melanoma cells were not active in this respect. Our results support the notion that heparins have antimetastatic activity.

Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis

The gastric mucosal surface was observed using the magnifying fibergastroscope (FGS-ML), and the fine gastric mucosal patterns, which were even smaller than one unit of gastric area, were examined at a magnification of about 30. For simplicification, we classified these patterns by magnifying endoscopy in the following ways; FP, FIP, FSP, SP and MP, modifying Yoshii's classification under the dissecting microscope. The FIP, which was found to have round and long elliptical gastric pits, is a new addition to our endoscopic classification. The relationship between the FIP and the intermediate zone was evaluated by superficial and histological studies of surgical and biopsy specimens. The width of the band of FIP seems to be related to the severity of atrophic gastritis. Also, the transformation of FP to FIP was assessed by comparing specimens taken from the resected and residual parts of the stomach, respectively. Moreover, it appears that severe gastritis occurs in the gastric mucosa which shows a FIP. Therefore, we consider that the FIP indicates the position of the atrophic border.