Endocrine Abstracts

Ki-67 can be solely detected within the cell nucleus, whereas in mitosis, most of the Ki-67 proteins are located on the chromosome surface. Ki-67 is present during all phases of the cell cycle (G1, S, G2, and M), but BrdU is only present in the S phase. This study examined whether it is possible to establish a developmental neurotoxicity test in human neural progenitor cells using Ki-67 instead of BrdU (5-bromo-2’-deoxyuridine). In the present study, Ki-67-expressed ReNcell CX cells, a human neural progenitor cell line, were evaluated as a marker of proliferation in neurotoxicity, compared to propidium iodide (PI) and BrdU. ReNcell CX cells were treated with developmental neurotoxic chemicals (aphidicolin, hydroxyurea, cytosine arabinoside, 5-fluorouracil, and ochratoxin A) or non-neurotoxic chemicals (sodium gluconate, sodium bicarbonate, penicillin G, and saccharin). The PI-positive cell numbers were increased in neurotoxic chemicals (10–⁴ and 10–⁵ M), and non-neurotoxic chemicals (1 and 10–² M) compared to the control, whereas the number of BrdU-positive cells decreased when exposed to the neurotoxic chemicals (10–⁴ and 10–⁶ M) and non-neurotoxic chemicals (1 and 10–² M). Furthermore, the number of Ki-67-positive cells decreased when exposed to high doses of neurotoxic chemicals (10–⁴ and 10–⁶ M) compared to non-toxic chemicals (1 and 10–² M). On the other hand, the number of Ki-67-positive cells decreased when exposed to non-neurotoxic chemicals at high doses (1 and 10–² M). Furthermore, there was no difference in the results of BrdU and Ki-67, suggesting that Ki-67 could be used as a proliferation marker instead of BrdU in ReNcell CX cells

Keyword: Ki-67, ReNcell CX, PI, BrdU.