I was always fascinated by the cartoon character of the
Tasmanian Devil. It has the classic lines of a naughty, rowdy, energetic
devilish sort of look to it.
But then I found out after some reading that these are
actually carnivorous marsupials and exist in the real world in Tasmania. They have a stocky
and muscular build covered by a black fur, exude a pungent odour, are extremely
loud with a annoying screech, a very keen sense of smell, and they feed with an
unmatched ferocity. These creatures actually exist but have a shortened life
span. Most die by four years of age. In the 1996 it was discovered that the Tasmanian
Devils were developing a devil facial tumor disease (DFTD) that restricted
their ability to feed and the cause of death was from starvation and organ
failure. The facial tumors when studies revealed molecular characteristics of
the Schwann nerve cell.
The declining population of the Tasmanian Devil was
attributed to the DFTD.
The devils are a promiscuous lot and those dominant
keep a tight control on their female counterparts. The mating process leads to
a lot of biting among the competitors and the male and females. The biting was
noted to be the mode of transmission of the DFTD. SO here was a cancer that was
transmitted by contact in a marsupial. Interestingly facing extinction the
females that normally became sexually active at 2 years of age now started to
become pregnant at age 1 and then soon died after the mating period by age 2 or
3. The population of the devils rapidly decreased raising an alarm and thus rendering
the Tasmanian Devil as endangered species in 2004.
What interests us is the mode of transmission. Up until now
we humans were peripherally interested in this phenomenon. ”Ah the poor devils,
what a terrible fate to suffer from their sexual appetite,” one would say and
move on. But then this article appeared about breast cancer cells and suddenly
the alarm bells should be going on. The bell has been rung and cannot be un-rung!
It turns out that breast cancer cells based on this study
exude exosomes, encapsulated vesicles, with their waste-products of short
fragments of their RNAs. These exosomes when transplanted or via endo-phagacytosis
find themselves within the interior of a normal cell have the capacity to
override the nuclear machinery of that cell and convert it into a cancerous
cell. It has been previously known that the exosomes transfer chemotherapy resistance, but this is the first link of transfer tumorogenesis.
This finding has tremendous relevance to our way of thinking. Cancer
transmission is more than genetic mutations passed down through generations or
acquired sporadically through external influences such as chemicals and viruses
and other such products of nature and man. It now appears that cancer cells by
virtue of their ability to discard their effete products can do the same! ( http://www.cell.com/cancer-cell/abstract/S1535-6108(14)00368-7 ) and ( http://www.nature.com/news/cancer-cells-can-infect-normal-neighbours-1.16212 )
Maybe it is time to rethink our strategies and include a
mechanism to subvert the cancer cell exosome production and extrusion and it's accumulated detritus that would choke off a cancer cell’s survival. Maybe?
Interesting to ponder upon, don’t you think?
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