Object: To investigate the influence of different microenvironments on tumor microcirculation patterns and invasiveness capability.
Methods: Melanoma B16 cells were injected into the abdominal cavity and skeletal muscle of C57 mice synchronously. CK-18 expression in melanoma was assessed to distinguish the malignant phenotype of tumors in the abdominal cavity from that in the skeletal muscle. HIF-1alpha, MMP-2 and MMP-9 expression and mRNA levels of MMP-2 and MMP-9 was detected to compare the mRNA levels of MMP-2 and MMP-9 from the two microenvironments. Cells positive for each immunohistochemical stain and the vessels representative of each type of microcirculation pattern were counted in two microenvironments.
Results: CK-18 and HIF-1alpha expression of melanoma were significantly higher in the skeletal muscle than in the abdominal cavity (P<0.05). Compared with the abdominal cavity, melanoma cells in the skeletal muscle overexpressed MMP-2 and MMP-9 (P<0.05). Real time-PCR results also showed that MMP-2 and MMP-9 mRNA levels of melanoma were higher in the skeletal muscle than in the abdominal cavity (P<0.05). VM channels and endothelium-dependent vessels were the major microcirculation pattern in the skeletal muscle and in the abdominal cavity, respectively.
Conclusion: Different microenvironments affect invasiveness and blood supply patterns of melanoma.