Al-Ghoul, Mohammad A.

Melanoma starts on the surface of the skin where it is easily seen. It is curable
when detected early, but can be fatal if allowed to progress and spread. Melanoma can
spread downwards through the skin, ultimately reaching the blood and lymphatic vessels,
and metastasize. Thus, one goal is to detect melanoma early before it metastasizes. A high
throughput proteomics approach has been applied to better understand the processes that
underlie tumor formation and progression. Three studies were pursued: I) proteome
comparison of the matched primary WM-115 and metastatic WM-266-4 melanoma cell
lines; II) proteome comparison between the matched melanoma Hs 895.T and fibroblast
Hs 895Sk cell lines; and III) comprehensive proteome cataloging of two metastatic
melanoma cell lines Hs 895.T and SK-MEL-2. From these studies we identified proteins
that are involved in cellular functions such as metabolism, signal transduction, and DNA
binding, as well as structural and heat shock proteins. We hypothesized about a possible
oxidative stress pathway involved in melanoma progression, initiated the creation of a
melanoma proteome database, and also identified some proteins not previously studied in melanoma (such as cyclophilin A, ADP-ribosylation factor-1, 14-3-3 zeta ATP syntase, Rho
GTPase, Plastin T, galectin 1 and 3, annex in II, enolase 1, cofilin, RhoGDI, Rap 1,
G6PG, GAPDH, TKT, HK, and nuclear chloride channel protein). These results mark a
step forward in the development of a metstatic melanoma protein database, the
understanding of the chemical pathways that are involved in metastatic melanoma
development, and identification of possible new targets for inhibitor development.

The metastatic process involves tumor cell adhesion to basement membrane components, such as type IV collagen. A specific mitogen activated protein kinase cascade is activated by cell adhesion to type IV collagen. This activation causes the expression of proteolytic enzymes. These enzymes will then participate in compromising extracellular matrix components and enhance cell movement through them. To better understand tumor invasion of type IV collagen, we have constructed triple-helical peptide (THP) ligands for melanoma cell receptors, and used these ligands to determine if receptors such as CD44/CSPG and the alpha2beta1 integrin have unique matrix metalloproteinase (MMP) signaling pathways affected by the tyrosine kinase inhibitor genistein. MMP protein expression profiles were evaluated using the alpha2beta1 integrin ligand, and CD44/CSPG ligand. Results were indicative of specific activation sequences that tumor cells undergo upon binding to select regions of type IV collagen.