Sporosis: A Source of undifferentiated cells in the human sarcoma line HT-1080
aUniversity of Latvia Institute of Experimental and Clinical Medicine, Riga, Latvia, bLatvian National Hematology Center, Riga, Latvia
AIM. The aim of this study was to demonstrate sporosis - the transformation of coiled bodies into microcells - using the fluorescence resonance energy transfer technique, and also to investigate the cytochemical features of the microcells. METHODS. Microcell development was induced by incubation of human sarcoma line HT-1080 cells in medium containing thiophosphamidum (10-20 μg/ml) or vincristinum (2-5 ng/ml) for 24 h. Fluorescence resonance energy transfer from 8-anilino naphthalene-1-sulfonic acid NH4-salt (ANS) to ethidium bromide (EB) was used for identification of coiled bodies and microcells. The cells were then stained with protein stain 8-anilino naphthalene-1-sulfonic acid (ANS, donor chromophore, 5 µg/ml) and nucleic acid stain - ethidium bromide (EB, acceptor chromophore, 3 µg/ml) and excited with ultraviolet light band at 365 nm. RESULTS Under these staining conditions the coiled bodies, being proteinaceous structures, showed bright blue fluorescence. The coiled bodies progressively accumulated pink fluorescent material and thereby transformed into micronuclei. Bright blue fluorescent cytoplasm appeared around the micronuclei. The microcells expressed strong NAD(F)H diaphorase, acidic phosphatase and nonspecific esterase activity. The microcells rapidly enclosed India ink and lithium carmine and showed very strong cytoplasmic acridine orange (red fluorescence) accumulation. In addition, microcells expressed a macrophage CD 68 protein and vimentin, a mesenchymal protein. The microcells arising via sporosis are viable, actively endocytocing immature macrophage-mesenchyme like cells. CONCLUSION. Dedifferentiation and macrophage-mesenchymal transformation of human sarcoma line-1080 cells likely occurs via sporosis.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in poster session 893 (Molecular pathology).