J. Czuwara-ladykowska et al., The inhibitory effects of camptothecin, a topoisomerase I inhibitor, on collagen synthesis in fibroblasts from patients with systemic sclerosis, ARTHRITIS R, 3(5), 2001, pp. 311-318
The main manifestation of systemic sclerosis (SSc) is the overproduction of
extracellular matrix, predominantly type I collagen. This study was undert
aken to evaluate the effects of noncytotoxic doses of the topoisomerase I i
nhibitor camptothecin (CPT) on collagen production in the activated dermal
fibroblasts from patients with SSc and healthy donors. The fibroblasts were
cultured in the presence or absence of CPT. Production of collagenous prot
eins by fibroblasts was determined in cell and matrix layers by ELISA and i
n conditioned media by [H-3]proline incorporation, gel electrophoresis, and
autoradiography. Expression of alpha2(I) collagen (COL1A2) mRNA was measur
ed by northern blot, and the activity of COL1A2 promoter was determined by
a chloramphenicol acetyltransferase, assay. CPT (10(-7) M) decreased the de
position of type I collagen by 68%, of type III by 38%, and of type VI by 2
1% in SSc fibroblasts and to a lesser degree in healthy controls. Similarly
, CPT (10(-8) M to 10(-6) M) significantly inhibited secretion of newly syn
thesized collagenous proteins into conditioned media by 50%. CPT (10(-8) M
to 10(-6) M) caused a significant dose-dependent inhibition of COL1A2 mRNA
levels and COL1A2 promoter activity, both by as much as 60%. The inhibitory
effect of CPT on collagen production by fibroblasts from patients with SSc
suggests that topoisomerase I inhibitors may be effective in limiting fibr
osis in such patients.