MORE LIGHT ON CANCER

Linda and Carolyn ready for a hot double date

1967

Some few weeks ago I wrote a blog about an advancement, seemingly an important one, involving a compound – combretastatin,  if you are curious - derived from a tree called the South African bushwillow.  Combretastatin A-4, one type of the stuff, comes in two “isomers” – that is, it comes in two forms with the same chemical formula but different structures.  It appears that one isomer is all but entirely innocuous when applied to cells, but the other is hell on wheels – it prevents proper cell division.  Two clever German scientists have discovered that, by slightly modifying the stuff, they can produce a compound that can be switched from one isomer to the other simply by illuminating it with harmless blue light.  The game plan, then, would seem to be – suffuse the body with the harmless isomer, then use a sharply focused beam of blue light to turn it into the lethal form wherever a piece of tumor is detected.  To me this line of research seems very promising, but it is early days.

Read the article itself at:  http://www.economist.com/news/science-and-technology/21657352-optical-switching-may-abolish-side-effects-cancer-drugs-colourful

and/or my original discussion: http://ljb-quiltcutie.blogspot.com/2015/07/trees-are-our-friends.html

Well, now, more on light.  First of all, reading the first part of this blog you may have thought something along the line of “Well, great – but how do you know where all the bits of metastases are?”  Hurray!  There is a compound called naphthalocyanine which can be administered prior to surgery, which will cause the tumor bits to glow, presumably rendering them easy to zap.      

Now, several equally clever scientists – at Oregon State and U. Nebraska – have developed another therapy employing light.  Their approach is to flood the patient (mice, so far) with a chemical called phthalocyanine (note similarity to the unpronounceable word in the preceding paragraph.)  This compound has the ability to produce “reactive oxygen species” that can kill cells, but only when subjected to a beam of near-infrared light. To render the cancer cells defenseless a “gene therapy” (mostly unexplained) also is administered.  Apparently the cancer cell’s resistance to these “reactive oxygen species” is entrusted to a protein named DJ1.  Also, I surmise, gene therapy in this case consists of producing a superabundance of the right type of siRNA (short interfering RNA, a mysterious (to me) little critter that, as its name implies, interferes with lots of biochemical processes.) So, then, illuminate the tumor for the surgeon, cut out as much as possible, administer this gene therapy stuff to throttle the DJ1, and kill any remaining bad stuff with phthalocyanine and a light beam.  Simple as pie?  Probably not.

So, as I have said many times before: these therapies may not solve the cancer question, but maybe they will.  And, it warms my heart to read about smart people like these people working hard on my number one goal for humanity – the elimination of deaths from ovarian cancer.

Read this:  http://medicalxpress.com/news/2015-08-advance-photodynamic-therapy-approach-ovarian.html

And if you read all the way through this over-long bit of biochemical blundering, I’m proud of you.  Go have a beer.