Thomas Mahoney wrote:
[snip]
> >> >> (Biochemistry (Mosc) 1997 Nov;62(11):1296-305
> >> This paper, however is right on point. The "transformation" they are
> >> referring to is the escape from the initial senescence block at 10
> >> population doublings. There are no anaplastic or malignant transformations
> >> noted in either the cell lines with active telomerase nor those lacking
> >> telomerase
> >
> >Sure, but that doesn't mean that they are normal. You have just noted
> >that, in vivo, "At this stage the tumor is somewhat anaplastic in that it
> >does generate additional capillaries through angiogenesis and the cellular
> >matrix and orientation is disrupted". Something causes the slow growth,
> >then something causes escape from it. Cells that have escaped it are thus
> >not normal, period.
>> I think I disagree:-( If this slow growth stage is similar to quiescence
> then the cells would be "normal" both before and after experiencing this slow
> growth stage and that appears to be the case. The mouse may die from the
> resulting tumor but that may be the "normal" situation for mice and in any
> case the cells themselves, probably, remain unchanged.
>> I may, however, agree with you:-) If there is some cellular change that
> initiates this slow growth stage, such as telomeric shortening on a single
> chromosome, then the cells may be experiencing a true senescence. If this or
> something similar is causing this slow growth stage then the cells, post
> senescence, would not be "normal".
Telomeric shortening or no, I have to agree with Aubrey. You say
"The mouse may die from the resulting tumor but that may be the
"normal" situation for mice and in any case the cells themselves,
probably, remain unchanged." Is this even logically possible?
Can you die from a tumor formed from "normal" cells? I would
think that by definition, if the cells have lost contact
inhibition and are thus able to form a lethal tumor, they are not
normal.
Aubrey?
James
