In addition, a gross and histological examination of potential organ distant sites revealed the unique tumorigenic and metastatic Veliparib side effects phenotype of the colospheres: metastases were only observed in the case of colosphere injection (Figure 6B). Figure 6 Tumorigenic and metastatic phenotype of XenoCT320 colospheres. (A) Injections of a quantity equivalent to 4 �� 104 cells as colospheres, spheroids or single-cell suspension were administered in a subrenal capsule assay in nude mice. After 14 weeks, … Expression of colon cancer stem cell markers by colospheres Floating spherical cell cluster cultures, such as colon cancer spheres, mammospheres and neurospheres, have been described as being valuable models for cancer stem cell culture. The round compact morphology of colospheres resembles that of colon cancer spheres.

This observation and the fact that colospheres are more efficient than spheroids in the initiation of tumour growth and metastasis in immunodeficient mice led us to study the membrane expression of two cancer stem cell markers, CD133 and CD44, in XenoCT320 colospheres. We then compared this expression with that of human cancer cells in XenoCT320 tissue and with that of CT320X6 and CT320 spheroids (Table 1). Table 1 Expression of CD133 and CD44 in XenoCT320 xenograft, derived colospheres and CT320X6 and CT320 spheroids Colospheres, spheroids and carcinoma cells in xenograft highly expressed CD133. Even if the variability of the CD133+ cell number was high in colospheres and xenografts according to SEM, the profile of this cell sub-population was similar in parental xenograft and derived colospheres.

In contrast to CD133, CD44 was expressed to a weaker extent in human cancer cells in xenograft tissue and colospheres than in spheroids. All CD44+ cells were CD133+ in colospheres and xenografts, whereas a sub-population of CD44+/CD133? cells was present in spheroids. Furthermore, the CD133 and CD44 phenotype of colospheres remained stable even after 21 days of ex vivo culture (Flow cytometry data: 47.9%��14 CD133+ cells, 2.1%��1.8 CD44+ cells, at D21, three independent experiments). Discussion This study reports the identification of colospheres, a newly characterised 3D cancer cell model directly obtained from dissociated human CRC tissue and associated with tumour aggressiveness. This model differs first from classical spheroids in that colospheres are obtained after short-term culture and not with permanent cell lines and, second, in that colospheres and spheroids clearly display distinct Entinostat phenotype features. The first step of this work was based on a large series of primary colon tumour specimens collected from 203 patients. After mechanical disruption, 98 tumours led to colospheres.