Re: clever chinese surgeons turn tumor into ball of ice

Date: Mon Feb 14 2000 - 11:31:18 MST

In a message dated 2/14/00 4:53:08, Anders Sandberg wrote:

> writes:
>> Another problem with cancer cryotherapy is that cryotherapy
>> tends not to kill *all* the cells. A few get lucky during the
>> thaw and one cell is all it takes.
>Since cancers tend to evolve heavily, this might be a way of
>discovering genes useful for cryopreservation. Just freeze a cultured
>tumour, unthaw it, let the surviving cells divide, freeze again, and
>so on. Eventually you would evolve tumour cells that could deal with
>freezing quite well, and you could start looking for the genes

That's a real cute idea. Even better, cancer cells often
develop resistance by altering regulation of genes, which
creates more opportunities for pharmocological intervention.

Vladmir Gelfand did this (for other purposes) while trying
to preserve a melanin-producing cell line. Freezing pops
the melanin-containing organelles and the release of
melanin kills the cells somehow. He put the cells through
several freeze-thaw cycles; he ended up with a line that
adapted by making very little melanin (grey cells, he calls
them.) So it's definitely *possible*, although melanophores
are a bit odd freezing-wise.

It might be interesting to see if HeLa cells or some other
such workhorse has already developed such tendencies (i.e.
compare an old frozen line to one that's been through lots
of cycles)

>The hard part is to do this in vivo rather than in vitro,
>since we want cryoprotectant mechanisms that work on tissues rather
>than single cells.

I think a cryopreservation trick might be useful even if
you couldn't do full-tissue preservation with that one trick.
It's a pretty cheap and painless experiment, anyway.

P.S.: The problems with melanophore freezing apply to
human melanophores too. A successfully revived corpsicle
might end up an albino even if the other problems were
successfully resolved.

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