Angioarchitecture of tumors induced by two different cloned cell lines established from a transplantable rat malignant fibrous histiocytoma.
Angiogenesis, a biologic process whereby endothelial cells divide and migrate to form new blood vessels, is a key step in tumor growth, invasion, and metastasis. In the present study, we investigated the differences in angioarchitecture between two different tumors induced by cloned cell lines (MT-8 and MT-9), derived from a transplantable rat malignant fibrous histiocytoma, by scanning electron microscopy of vascular corrosion casts. During a 3-week observation period after implantation, the growth of MT-8 tumors appeared to be faster than that of MT-9 tumors. Histologically, MT-8 tumors were of the uniformly undifferentiated sarcoma type arranged in characteristic organoid structures, and MT-9 tumors showed a storiform growth pattern. In MT-8 tumors, neovascularization occurred by sprouting at postimplantation (PI) week 1, and the newly formed capillaries gradually became more tortuous. In MT-9 tumors, at PI week 1, the corrosion casts of newly formed capillaries mainly showed a wavy course but no finger-like outgrowths of capillaries were seen. At PI weeks 2 and 3, the sprouting was seen specifically in MT-9 tumors, forming basket-like structures and glomeruloid structures of capillaries. These results indicate that angiogenesis or angioarchitecture of MT-8 tumors is different from that of MT-9 tumors, depending on the differences in their tumor histology and by the features like absence or presence of basket-like structures and glomeruloid structures of capillaries.
Tsunenari
Ichiro
I
Kawanishi Pharma Research Institute, Nippon Boehringer Ingelheim Co., Ltd., 3-10-1 Yato, Kawanishi, Hyogo 666-0193, Japan. tsunerari@boehringer-ingelheim.co.jp
Yamate
Jyoji
J
Iwaki
Masae
M
Kuwamura
Mitsuru
M
Kotani
Takao
T
Sakuma
Sadashige
S
D000818:Animals; D002455:Cell Division; D002999:Clone Cells; D018219:Histiocytoma, Benign Fibrous / Q000098:blood supply* / Q000473:pathology* / Q000648:ultrastructure; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344; D014407:Tumor Cells, Cultured