Trowsdale J, Hoch J A
Oncodev Biol Med. 1982;3(5-6):391-402.
Many human tumor cell lines produce alkaline phosphatases (APs) whose expression is normally not associated with the tissue where the tumor originated. The control of high level AP expression in three cloned human tumor cell lines was examined after fusion to murine fibroblast cell lines. The human tumor cell lines studied were: HeLa 71.5, producing term placental AP, D98.8, producing fetal intestinal AP and Hs578T.12, producing a liver-like AP. After fusion to the murine fibroblast cell lines IT22 or CL1D and propagation of the hybrids, the presence of human chromosome markers and the levels of AP were determined. Hybrids of either murine line fused to HeLa 71.5 or D98.8 cells never gave rise to proliferating clones with significant levels of their respective APs, even when several hundred hybrids were examined, in situ, at early and later stages of proliferation. Consequently, the abundant AP production normally found in HeLa 71.5 and D98.8 cells may require products from a number of chromosomes or the mouse cytoplasm is able to extinguish AP expression. Hybrids formed between the Hs587T cell line and either murine line continued to express liver-like AP. This expression was maintained in HAT selection medium and eliminated with bromodeoxyuridine counter selection. This result suggests that the control of liver-like AP in human tumors differs from that of the full-term placenta of fetal intestine.
许多人类肿瘤细胞系会产生碱性磷酸酶（APs），其表达通常与肿瘤起源的组织无关。在与鼠成纤维细胞系融合后，研究了三种克隆的人类肿瘤细胞系中高水平AP表达的调控情况。所研究的人类肿瘤细胞系包括：产生足月胎盘AP的HeLa 71.5、产生胎儿肠AP的D98.8以及产生类肝AP的Hs578T.12。在与鼠成纤维细胞系IT22或CL1D融合并使杂种细胞传代后，测定了人类染色体标志物的存在情况以及AP的水平。无论是与HeLa 71.5细胞还是D98.8细胞融合的鼠细胞系杂种，即使在增殖的早期和后期对数百个杂种细胞进行原位检测，也从未产生过具有显著水平各自AP的增殖克隆。因此，HeLa 71.5和D98.8细胞中通常大量产生的AP可能需要多个染色体的产物，或者小鼠细胞质能够抑制AP的表达。Hs587T细胞系与任一鼠细胞系形成的杂种继续表达类肝AP。这种表达在HAT选择培养基中得以维持，并通过溴脱氧尿苷反选择被消除。这一结果表明，人类肿瘤中类肝AP的调控与足月胎盘或胎儿肠的调控不同。
