What do the glioma cell line prefixes LN and U stand for ? - (Feb/24/2015 )

I'm looking for the meaning of the cell line prefixes "LN" and "U" of some glioma cell lines. Unfortunately, I didn't find any information on the internet, including websites like ATCC. Does anyone happen to know what these letters actually stand for or why they were chosen ?

Thanks.

Often these sorts of things are obscure, I think in the case of the "U" lines it stands for Uppsala, the city where the lines were first developed. However, it often is a name applied by the researcher which could be any one of a number of things, e.g. a line might use a researcher's initials or be part of a alpha-numeric progression.