2Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, 119991 Moscow, Russia; fax: +7 (495) 939-3181; E-mail: email@example.com
3Department of General, Visceral, and Transplant Surgery, Ludwig-Maximilians-University, 81377 Munich, Germany; fax: +49 (89) 4400-76433; E-mail: firstname.lastname@example.org
* To whom correspondence should be addressed.
Received April 8, 2014
Some photoreceptor proteins normally specific for the eye retina are aberrantly expressed in malignant tumors. These proteins include recoverin, visual rhodopsin, transducin, cGMP-phosphodiesterase 6 (PDE 6), cGMP-dependent cationic channels, guanylyl cyclase 1, rhodopsin kinase, and arrestin. By analogy with cancer-testis antigens, these photoreceptor proteins form the group of cancer-retina antigens. It is shown that an aberrant demethylation of the promoter region of recoverin is involved in the aberrant expression of this protein. The cascade Wnt5a → Frizzled-2 → transducin → PDE 6 is shown to function in skin melanoma cells, and this suggests that these cancer-retina antigens can play a functional role. The events accompanying the signal transduction in this cascade, including those involving calcium ions and cGMP-dependent protein kinase (protein kinase G), are discussed.
KEY WORDS: visual transduction, retina, cancer-retina antigens, aberrant expression, cancer