by J. Travis Six generations of mutant mice have put a damper on
one of the hottest areas in cancer research, although some
scientists warn against a pessimistic rush to judgment. The mice
lack a component of telomerase, an enzyme that fastens short
sequences of DNA to the ends of chromosomes. These so-called
telomeres protect the tips and serve as buffers, since a bit of
every chromosome tip is lost whenever cells divide (SN:
11/25/95, p. 362). Except for the germ cells, which give rise to
sperm and eggs, few adult human cells seem to produce
telomerase. Yet most cancer cells do make the enzyme, prompting
speculation that tumor cells need it to keep dividing.
Consequently, many scientists have hailed the idea of inhibiting
telomerase as a promising strategy for treating cancer. That
hypothesis is under fire now that a team of scientists has shown
that cells from telomerase-deficient mice form tumors.
Telomerase inhibition "may not be the phenomenal approach that
we all hoped and prayed for," says Ronald A. D