Correlation of tumor phenotype with c-fms proto-oncogene expression in an in vivo intraperitoneal model for experimental human breast cancer metastasis.

Although proto-oncogene expression has been shown to correlate with clinical outcome in breast carcinoma, an experimental model has not been proposed to study this phenomenon in vivo. In addition, the ability to modulate this proto-oncogene in vivo to correlate with phenotypic behavior has not been determined. Utilizing an intraperitoneal model for metastatic spread with BT20 human breast carcinoma cells, clonally expanded cells expressing five fold higher c-fms protein were compared with parent BT20 cells as well as an underexpressing clone using intrasplenic injection following left flank cut-down in female nude and Severe combined immunodeficient (SCID) mice. Athymic BALB/c nude and SCID animals were observed for clinical evidence of tumorigenicity with necropsy performed at either 50 or 80 days unless compromised earlier. Immunohistochemistry (IHC) of the harvested tumors was performed to correlate c-fms expression from its original in vitro culture to the in vivo model. At day 50, differences in primary tumor take and spread to the pelvis were already evident favoring the c-fms over-expression group with IHC of these tumors revealing significantly higher intensity of staining for c-fms, (mean H score of 205 vs. 43 in the over-expression and parent groups, respectively). At day 80, tumor take and spread was comparable; however, tumor size in the over-expression group was significantly larger than the parent and under-expressing group in both the BALB/c and SCID experiments. Modulation of c-fms proto-oncogene expression was also achieved using the anti-glucocorticoid, RU-486, via oral administration to SCID mice with subsequent correlation to IHC staining. This model thus provides tumors of significant size and organ diversity which retain their phenotype early in tumorigenesis allowing an early endpoint to assess efficacy of novel treatments.

Regulation of endometrial stromal cell matrix metalloproteinase activity and invasiveness by interleukin-8.

OBJECTIVE: To evaluate the effect of interleukin-8 (IL-8) on endometrial stromal cell metalloproteinase (MMP) activity and invasiveness. DESIGN: Experimental laboratory study. SETTING: University medical center. PATIENT(S): Reproductive age women without endometriosis. INTERVENTION(S): Endometrial stromal cells were grown in culture and treated with recombinant IL-8 (0.0001-10 ng/mL) for 24 to 48 hours. Supernatants were collected for soluble assay of collagenase activity and gelatin zymography. Endometrial stromal cells were plated on 8-microm pore membranes coated with Matrigel or human simple matrix and treated with IL-8 for 48 hours. MAIN OUTCOME MEASURE(S): Collagenase activity and MMP2 and 9 activity of control vs. IL-8 treated endometrial cells, and number of endometrial cells that invade through Matrigel or human simple matrix. RESULT(S): Collagenase activity in cells treated with IL-8 (1-10 ng/mL) was higher than in control cells. On gelatin zymograms, MMP2 and MMP9 activity of endometrial stromal cells was stimulated by IL-8 treatment (1-10 ng/mL). The number of cells that invaded the Matrigel or human simple matrix was 1.7-fold higher in the group treated with 10 ng/mL of IL-8 compared with the control group. CONCLUSION(S): IL-8 increases MMP activity and invasive capability of endometrial stromal cells in culture; IL-8 may be involved in the pathogenesis of endometriosis and menstrual physiology.