Tacalcitol is a calcitriol analogue, regulates calcium metabolism by stimulating intestinal calcium absorption and influencing bone turnover. But tacalcitol has no significant change in bone formation [1]. Tacalcitol can be used in the research of inflammation, breast cancer, and skin diseases, and prevent the osteoporosis that results from the development of cancer or from chemotherapy or hormone therapy [2-3].
In vitro, treatment of normal human keratinoeytes with tacalcitol (0.01-1μM; 48h) increased the numbers of involucrin positive cells and induced cell differentiation [4].
In vivo, tacalcitol (1.0µg/kg; s.c.; thrice weekly) decreased bone column density, transiently decreased the metastatic spread of 4T1 breast carcinoma without influencing primary tumour growth or angiogenesis in old ovariectomized (OVX) mice [2]. While tacalcitol (1.0µg/kg; s.c.; thrice weekly) increased metastatic spread in young mice bearing 4T1 breast cancer [5].
References:
[1] Yamada, S., J-P. Bonjour, and H. Fleisch. "Effect of 1α, 24 (R)-dihydroxyvitamin D3 on calcium metabolism in the rat." European Journal of Endocrinology 111.4 (1986): 572-576.
[2] Anisiewicz, Artur, et al. "Calcitriol analogues decrease lung metastasis but impair bone metabolism in aged ovariectomized mice bearing 4T1 mammary gland tumours." Aging and disease 10.5 (2019): 977.
[3] Matsumoto, Kunio, et al. "Effect of 1, 24R‐dihydroxyvitamin D3 on the growth of human keratinocytes." The Journal of Dermatology 17.2 (1990): 97-103.
[4] Kobayashi, Teruaki, et al. "1α, 24R‐dihydroxyvitamin D3 has an ability comparable to that of 1α,25‐dihydroxyvitamin D3 to induce keratinocyte differentiation." The Journal of Dermatology 17.11 (1990): 707-709.
[5] Anisiewicz, Artur, et al. "Unfavorable effect of calcitriol and its low-calcemic analogs on metastasis of 4T1 mouse mammary gland cancer." International journal of oncology 52.1 (2018): 103-126.
Tacalcitol是骨化三醇（Calcitriol）类似物，通过刺激肠道钙吸收和影响骨骼转换来调节钙代谢。但骨化醇对骨形成没有显著影响[1]。Tacalcitol可用于炎症、乳腺癌和皮肤病的研究，并能预防癌症发展、化疗或激素治疗所导致的骨质疏松症[2-3]。
在体外，用Tacalcitol（0.01 - 1μM；48小时）处理正常的人类角质形成细胞，可增加包涵蛋白阳性细胞的数量，并诱导细胞分化[4]。
在体内，Tacalcitol（1.0µg/kg；皮下注射；每周三次）可降低骨柱密度，暂时减少4T1乳腺癌的转移扩散，但不影响老年卵巢切除（OVX）小鼠的原发肿瘤生长或血管生成[2]。然而，在携带4T1乳腺癌的年轻小鼠中，Tacalcitol（1.0µg/kg；皮下注射；每周三次）会增加癌症转移扩散[5]。