TBJ murine neuroblastoma resists dibutyryl cyclic AMP-induced differentiation and effects on metalloproteinase secretion

Abstract

Background: Nonmetastatic C1300 murine neuroblastoma and TBJ, a metastatic variant, exhibit different mechanisms of metastasis and invasion.

Methods: In this study, they were examined for response to 1 mmol/L dibutyryl cyclic AMP in vitro.

Results: (1) dCAMP induced morphological differentiation in 20% to 40% of C1300 cells, whereas TBJ resisted differentiation. (2) Untreated TBJ expressed 92-kDa metalloproteinase, whereas C1300 expressed none. These results were not affected by dCAMP. (3) Growth curves of untreated C1300 and TBJ were exponential. Dibutyryl CAMP induced a plateau in C1300 growth that was confirmed by increased S-phase cells by cell cycle analysis.

Conclusions: TBJ growth was unaffected by dCAMP. Apoptosis, as assayed by Hoechst-merocyanine staining test, was not involved in the growth plateau.