Flexible-Heteroarotinoids
(Flex-Hets)
To eliminate cancer cells without harming
healthy cells is the ultimate objective of cancer prevention. This objective appears to be met by a novel class
of synthetic compounds called Flexible Heteroarotinoids (Flex-Hets). In vivo
studies demonstrated that Flex-Hets induce differentiation and inhibit tumor
growth and angiogenesis without evidence of toxicity, skin irritation or
teratogenicity.
It appears that Flex-Hets directly target abnormalities
found in cancer mitochondria, without harming healthy mitochondria, because
normal cells derived from the same organ site as their corresponding cancer
cell lines are drastically less sensitive to Flex-Het effects on mitochondria
and apoptosis. Furthermore, Bcl2 family
mitochondrial proteins are regulated in opposite directions in normal versus
cancer cells by the lead Flex-Het, SHetA2 (1).
Inhibition of cancer cell growth is accompanied by G1 cell
cycle arrest and degradation of Cyclin D1 (2, 3).
SHetA2 inhibits the activity of the NF-kB transcription
factor through inhibition of IKK phosphorylation and subsequent degradation of
the NF- kB inhibitor IkBa (4).
The regulation of Bcl-2 proteins, TP, VEGF and tenasxin C
by NF-kB, and the temporal effects of
SHetA2 on these proteins, suggest that NF-kB is one of the earliest proteins targeted by
SHetA2.
Anti-angiogenesis activity occurs through SHetA2
inhibition of angiogenic cytokine expression (5).
SHetA2 chemoprevention
activity was demonstrated in a 3-dimensional organotypic model of
endometrial carcinogenesis, in which the consistent DMBA
(7,12-dimethylbenz[a]anthracene) induction and SHetA2 prevention of the
cancerous phenotype were validated by karyometry. This carcinogenesis and chemoprevention was
validated in an independent laboratory.
Excreted proteins up-regulated by carcinogenesis and prevented by SHetA2
also were validated and may be useful biomarkers for cancer diagnosis.
5. Myers, T., Chengedza, S., Lightfoot, S.,
Pan, Y., Dedmond, D., Cole, L., Tang, Y., Benbrook, D.M. (2008) Flexible Heteroarotinoid (Flex-Het)
SHetA2 inhibits angiogenesis in vitro
and in vivo. Investigational New Drugs, Published
online: 18 September 2008.
http://www.springerlink.com/content/aj864j6707w47513/fulltext.pdf