Effects of a human myeloid chronic leukemia cell line (K562) on in vivo angiogenesis

Recent studies demonstrate that the prognosis of hematologic tumors such as leukemias and limphomas is strongly influenced, such as for solid tumors, by the ability of neoplasia to metastatize. Among the factors able to influence metastasis, cellular proliferation and cellular ability to sinthetize and release growth factors inducing angiogenesis play a crucial role. In this study we evaluated the role of Vitamin D in modulating the cellular proliferation and the ability to induce angiogenesis of a human chronic myeloid leukemia cell line. Cell line K562 has been cultured following standards methods of cell culturing. Basal cell proliferation and after treatment by pharmacological doses of vitamin D (10E-7M), have been measured by 3H thymidine incorporation. In vivo angiogenesis induced by K562, treated by 10E-7M vitamin D for 72 hours and untreated, has been qualitatively evaluated by chorioallantoic membrane assay (CAM). From this study emerges that cellular proliferation is significantly reduced after a 72 hours incubation in medium containing 10E-7M vitamin D. Furthermore, our reults show that K562 cell line induces a strong angiogenetic response in CAM assay which results significantly reduced after a 72 hours incubation in medium containing 10E-7M vitamin D. In conclusion, vitamin D induces a significant decrease of cellular proliferation and a strong reduction of in vivo angiogenesis. These data show that vitamin D might be involved in the control of angiogenesis which is frequently observed in metastasis induced by hematologic tumors.