Newly characterised ex vivo colospheres as a three-dimensional colon cancer cell model of tumour aggressiveness.
BACKGROUND
New models continue to be required to improve our understanding of colorectal cancer progression. To this aim, we characterised in this study a three-dimensional multicellular tumour model that we named colospheres, directly obtained from mechanically dissociated colonic primary tumours and correlated with metastatic potential.


METHODS
Colorectal primary tumours (n=203) and 120 paired non-tumoral colon mucosa were mechanically disaggregated into small fragments for short-term cultures. Features of tumours producing colospheres were analysed. Further characterisation was performed using colospheres, generated from a human colon cancer xenograft, and spheroids, formed on agarose by the paired cancer cell lines.


RESULTS
Colospheres, exclusively formed by viable cancer cells, were obtained in only 1 day from 98 tumours (47%). Inversely, non-tumoral colonic mucosa never generated colospheres. Colosphere-forming capacity was statistically significantly associated with tumour aggressiveness, according to AJCC stage analysis. Despite a close morphology, colospheres displayed higher invasivity than did spheroids. Spheroids and colospheres migrated into Matrigel but matrix metalloproteinase (MMP)-2 and MMP-9 activity was detected only in colospheres. Mouse subrenal capsule assay revealed the unique tumorigenic and metastatic phenotype of colospheres. Moreover, colospheres and parental xenograft reproduced similar CD44 and CD133 expressions in which CD44+ cells represented a minority subset of the CD133+ population.


CONCLUSIONS
The present colospheres provide an ex vivo three-dimensional model, potentially useful for studying metastatic process.
Weiswald
L-B
LB
IFR71 Sciences du Médicament, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, F-75006 Paris, France.
Richon
S
S
Validire
P
P
Briffod
M
M
Lai-Kuen
R
R
Cordelières
F P
FP
Bertrand
F
F
Dargere
D
D
Massonnet
G
G
Marangoni
E
E
Gayet
B
B
Pocard
M
M
Bieche
I
I
Poupon
M-F
MF
Bellet
D
D
Dangles-Marie
V
V
D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D045744:Cell Line, Tumor; D002465:Cell Movement; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D051379:Mice; D009361:Neoplasm Invasiveness; D014411:Neoplastic Stem Cells / Q000473:pathology; D010455:Peptides / Q000032:analysis; D018874:Spheroids, Cellular
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse