Association of increased tumor cell responsiveness to prostaglandin E2 with more aggressive tumor behavior.

Secretion of prostaglandin E2 (PGE2) by cloned variants of QR fibrosarcoma or of Lewis lung carcinoma (LLC) did not correspond with their in vivo aggressive behavior. However, aggressiveness may be influenced by tumor responsiveness to PGE2. Each of the metastatic LLC or progressor QRpP variants was more motile in an in vitro migration model than were either the nonmetastatic LLC or regressor QR variants. One of the two tested progressor QR variants and all of the metastatic LLC variants were also more responsive to PGE2 in their in vitro migration through a membrane than were either regressor QR or nonmetastatic LLC variants. Thus, responsiveness to PGE2 by tumors may regulate the degree of tumor aggressiveness in vivo.