Ultrastructural and cytochemical studies on cancer and apoptosis in bone.

我们研究了骨转移和骨侵袭的机制。肿瘤周围有一层由成纤维细胞组成的膜。这些细胞呈碱性磷酸酶阳性。TRAPase阳性细胞位于ALP ASE阳性细胞附近，邻近骨表面可见大量破骨细胞。肿瘤细胞分泌的PTHrP可能通过PTH/PTHrP受体免疫阳性的成骨细胞以旁分泌方式刺激破骨细胞分化和骨吸收。在骨转移中，乳腺癌细胞产生了血管内皮生长因子，并在骨中诱导了许多CD31阳性的血管。TRAPase阳性破骨细胞与RANKL阳性细胞直接接触。肿瘤细胞中的血管内皮生长因子可能通过成骨细胞的RANKL诱导肿瘤生长和破骨细胞前体细胞的生长，刺激破骨细胞的分化和激活。此外，我们还发现双膦酸盐抑制了骨转移区的破骨细胞和血管的数量。我们在体外研究了突变的ALPase诱发骨病的机制。突变的ALPase基因导致蛋白质合成，但不导致内质网到高尔基体的转运。然后，研究了用双磷酸盐处理的大鼠胫骨中破骨细胞的凋亡情况。它们变得没有皱纹，从骨表面脱落，并显示许多小泡的形成，高尔基体降解和DNA断裂。其中大部分被巨噬细胞清除，但也有一些逃逸到血管中。此外，我们发现，双膦酸盐直接影响破骨细胞，而不是介导其沉积到骨基质中。

We examined the mechanisms of bone metastasis and bone invasion. The tumor mass was surrounded by a membrane consisting of fibroblastic cells. These cells were positive for ALP ase. TRAPase-positive cells were localized close to the ALP ase-positive cells and numerous osteoclasts were observed on the neighboring bone surfaces. It seems that PTHrP secreted by the tumor cells appears to stimulate differentiation of osteoclasts and bone resorption in a paracrine manner through PTH/PTHrP receptor-immunopositive osteoblastic cells. In bone metastatic, breast cancer cells produced VEGF and induced many CD31-positive blood vessels in bone. TRAPase-positive osteoclasts directly contacted to RANKL-positive cells. It seems that VEGF of the tumor cells induce growth of cancer and osteoclasts progenitor, and stimulate differentiation and activation of osteoclasts via RANKL of osteoblastic cells. Furthermore, we found that bisphosphonate inhibited the number of osteoclasts and blood vessels in bone metastatic area. We investigated the mechanism which a mutant ALPase induced bone disease in vitro. The mutant ALPase gene resulted in protein synthesis but not ER-to-Golgi apparatus trafficking. Then, osteoclasts apoptosis were studied in the tibia of rats treated with a bisphosphonate. They became devoid of ruffled borders and detached from bone surface, and showed formation of many vesicles and degradation of Golgi apparatus and DNA fragmentation. The majority of them are eliminated by macrophages, but there are some that escape into blood vessels. Furthermore, we found that bisphosphonates directly affect osteoclasts without mediating its deposition to the bone matrix.