14515 Background: In vitro spheroid model using cancer cell lines is widely admitted to mimic in vivo micro tumors, including micrometastases. Floating spheroid cell cluster culture has been recently used for normal and cancer stem cell expansion. Spontaneously spheroids generated in vivo have been only studied in ovarian cancer ascites while organoid aggregates have been sometimes observed in the establishment of human colon cancer cell lines. In this study, we investigated whether spontaneous spheroid aggregates from colon cancer could be isolated and characterized. Methods: 127 colorectal primary tumor specimens have been collected and mechanically dissociated into small fragments, which were then shortly cultured on cell plastic flask. Production of spheroid- like structures, referred to as colospheres, was examined at Day 1 and colospheres were gathered for phenotypic characterization. Results: Colospheres were successfully generated from 67 surgical specimens (53%). The capacity to form colospheres was strictly restricted to tumor tissue: dissociated normal colon mucosa never generated colospheres and colospheres were formed exclusively by cancer cells. The ability to generate colospheres was demonstrated to be significantly related to tumor aggressiveness, according to nodal status and AJCC’s stages (Chi-2 test, p<0.05). Immunohistochemical studies showed that cells forming colospheres were frequently positive for Ki67, and displayed often a disturbed expression of the epithelial caretaker E-cadherin. Peripheral cells of colospheres were able to migrate into Matrigel in absence of any chemoattractant. Conclusions: Collectively, the morphology of these colospheres derived directly from tumoral tissues and made up exclusively of cancer cells, their potential capacity to acquire an epithelial-to-mesenchymal transition phenotype and their in vitro migration ability could be aligned with the collective migration properties of carcinomas. Consequently, these ex vivo spherical structures might form an in vitro cell system for micrometastasis studies, at the very time when mortality among colorectal cancer patients continues to be attributed to metastasis development. No significant financial relationships to disclose.
Lagerindicine, a New Pyrrole Alkaloid Isolated from the Flowers of Lagerstroemia indica Linnaeus