Dataset Information

Newly characterised ex vivo colospheres as a three-dimensional colon cancer cell model of tumour aggressiveness.

ABSTRACT:

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.

Conclusion

The present colospheres provide an ex vivo three-dimensional model, potentially useful for studying metastatic process.

SUBMITTER: Weiswald LB

PROVIDER: S-EPMC2720229 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Osteocytes are deeply embedded in the mineralized matrix of bone and are nonproliferative, making them a challenge to isolate and maintain using traditional in vitro culture methods without sacrificing their inimitable phenotype. We studied the synergistic effects of two microenvironmental factors that are vital in retaining, ex vivo, the phenotype of primary human osteocytes: hypoxia and three-dimensional (3D) cellular network. To recapitulate the lacunocanalicular structure of bone tissue, we assembled and cultured primary human osteocytic cells with biphasic calcium phosphate microbeads in a microfluidic perfusion culture device. The 3D cellular network was constructed by the following: (1) the inhibited proliferation of cells entrapped by microbeads, biomimetically resembling lacunae, and (2) the connection of neighboring cells by dendrites through the mineralized, canaliculi-like interstitial spaces between the microbeads. We found that hypoxia synergistically and remarkably upregulated the mature osteocytic gene expressions of the 3D-networked cells, SOST (encoding sclerostin) and FGF23 (encoding fibroblast growth factor 23), by several orders of magnitude in comparison to those observed from two-dimensional and normoxic culture controls. Intriguingly, hypoxia facilitated the self-assembly of a nonproliferating, osteoblastic monolayer on the surface of the 3D-networked cells, replicating the osteoblastic endosteal cell layer found at the interface between native bone and bone marrow tissues. Our ability to replicate, with hypoxia, the strong expressions of these mature osteocytic markers, SOST and FGF23, is important since these (1) could not be significantly produced in vitro and (2) are new important targets for treating bone diseases. Our findings are therefore expected to facilitate ex vivo studies of human bone diseases using primary human bone cells and enable high-throughput evaluation of potential bone-targeting therapies with clinical relevance.

Project description:Rationale: Continued reliance on preclinical animal models and traditional human cell culture experiments conducted on supraphysiologically stiff surfaces in two dimensions often limits the translation of cellular and molecular mechanistic findings into effective therapies for patients suffering from chronic obstructive pulmonary disease (COPD). COPD ranks as the fourth highest cause of mortality in the United States, and thus it is imperative to improve ex vivo models of this devastating disease. One emerging novel model of study involves using precision-cut lung slices as three-dimensional lung tissue culture (3D-LTC) platforms. Although this model retains the complex pulmonary architecture required for more precise ex vivo modeling, it is limited by short-term viability (?5–7 d). Objectives: We hypothesized that this decrease in viability is related to slices losing the extracellular matrix adhesion foundation critical for normal cellular functioning and that encapsulation of slices in custom hydrogel microenvironments would improve maintenance of a stable phenotype for longer-term investigational studies. Methods: The 3D-LTC slices tested here were created according to standard protocols from healthy mouse lungs and from the lungs of a patient with COPD. We synthesized poly(ethylene glycol)–based polymers to create custom hydrogels for encapsulation of 3D-LTCs with mechanical properties that match each type of lung tissue. The Young’s modulus (E) or stiffness of hydrogels was measured with a parallel-plate rheometer. Lung slices were analyzed for viability with a colorimetric assay that measures cellular metabolism (WST-1; Millipore Sigma) and by staining for cell membrane integrity (Invitrogen LIVE/DEAD viability kit; Thermo Fisher Scientific). All fluorescently labeled samples were imaged by spinning disk confocal microscopy, and cell viability at all time points was analyzed with ImageJ software. Results: The average percent viability of cells within hybrid 3D-LTCs was consistently higher than control 3D-LTCs on Day 1 (35% increase; P?<?0.001) and Day 7 (55% increase; P?<?0.001) according to LIVE/DEAD staining results. The WST-1 assay further showed no significant difference in viability between the two systems up to Day 18 in culture. Conclusions: We have demonstrated that it is possible to create customized hydrogel platforms that replicate the stiffness of healthy mouse and human COPD lung tissues. Precision cut lung slices embedded in these materials maintain higher levels of viability compared with controls in culture. Further optimization of this technology platform is ongoing and will facilitate the development of more organotypic ex vivo models of chronic pulmonary disease.