Infinite growth of normal cells in serum-free medium

Sydney Shall S.Shall at
Tue Apr 26 03:46:09 EST 1994

	There has been a query from Leonid Gavrilov concerning the
report from D. W. Barnes et al., that mouse cells have an infinite
life span in serum free medium. 

	I understand that the Barnes group have found that this
observation can not be reproduced with human cells.

	Clearly therefore the limit on life-span of normal human
cells ( the Hayflick phenomenon still exists).

	The explanation for the obsevation made by Barnes et al., is
still unclear.  I am not aware of any published report confirming the
observation. Also as another correspondent has already written, it is
unclear whether the observation is explained by the absence of serum
or by the presence of particular cell types in the Barnes
experiments.  It amy be that they were looking at cell types which
differentiate in the presence of certain growth factors.  A more
interesting possibility to me, is that in the Barnes' experiment
there were primordial embryonic cells which are in fact immortal.
This is a distinct theorectical possibility because we know that germ
cells are really immortal.

	It is also possible that the observation made by the Barnes'
group was due, as they suggested, to the presence of serum.  It is
worth considering that the very long term presence of either
stimulatory or inhibitory growth factors is part of the molecular
causation of the limited life-span.  I think this is unlikely because
the life-span number is both tissue and species specific, and this
implies a genetic origin to me.  Moreover, and more convincingly, we
have shown that in the human progeria disease, Werner's syndrome,
which is a single Mendelian locus disease, there is a change in the
length of the life-span of human fibroblasts.

	A repetition of the observation made by Barnes and coworkers
and an exploration of this result would be very worthwhile.



Sydney SHALL,
Laboratory of Cell and Molecular Biology,
Biology Building,
University of Sussex,
East Sussex BN1 9QG,

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