TELOMERES, TELOMERASE &, of course, CANCER

Relaxing on the beach somewhere

1988

Boy, am I ever pushing the envelope on this one!  I am going to write about something important, but that, truthfully, I barely understand. If that. Thus, what follows will be grossly oversimplified.  I just hope that it’s not dead wrong.  If it is, please let me know.  Politely.    I find this stuff fascinating so – if and when I learn more about it – I will add Comments to this post.    That should be about enough humility, so, here goes.  To do it Wikipedia style:

Mitosis:  Cell division, which entails duplication of the cell’s DNA.  One peculiarity of this process is that the very end of the chromosome cannot be copied.  This might cause loss or modification of genes, which would be bad news.  Fortunately there exist things called:

Telomeres:   These are peculiar, semi-useless, non-coding repeat sequences of nucleotides (in humans the sequence reads TTAGGG, where T stands for thymine, A for adenine, and G for guanine. Thus, your personal telomere consists of “TTAGGGTTAGGG& etc.”, strung out on the end of your chromosomes.  So does mine.   (You may have no idea about the structure or composition of these “bases”.  Neither do I.  If curious, ask my grand-daughter Olivia, who is out on a fishing boat at the moment – no doubt studying diligently in her spare time.)  Ordinarily, in a gene, the sequence of bases has unsurpassed significance, because it provides the blueprint for the manufacture of proteins.  However, the telomere sequence codes for nothing.  It is there only to protect the important (coding) part of the chromosome.  But for each cell division part of it is hacked off, which leads to:

Senescence and death:  Sooner or later your telomeres will all be used up, and important parts of your chromosomes will begin to disappear, be changed, swapped around, welded together or experience other pieces of bad luck.  Pretty soon thereafter your cells will throw in the towel and die, and –eventually – you with them.  To me, it seems like the secret to eternal life is to somehow replace the eroded ends of the telomere.  Oddly enough, there is a molecule capable of doing just that.  It is called:

Telomerase:  This is an enzyme that rebuilds the telomere.  However, in the normal course of things it is active only in fetal cells and things called “adult stem cells”, one of which resides in your bone marrow and renews your blood supply.  These have telomerase, but normal body cells don’t – which is why they grow old and die.  Interestingly:

Cancer cells:  At least many of them, have plenty of telomerase.  This is why they can go on rapidly dividing and not run out of telomeres and die.  Bad planning, it seems to me.  Anyway, it would appear that attacking telomerase in cancer cells is a promising approach to cancer therapy.  So says my 10-year-old biology textbook.  Even older research articles I’ve seen agree.  Then why is cancer still around?  I guess you can’t get at the telomerase in cancer cells without doing damage to essential adult stem cells elsewhere.  There ought to be some way to target the damned things.  Let’s get cracking!

This is quite enough biology for one bite.  Sorry.  I got carried away.