Background & aims: Advanced gastric cancer has a poor prognosis and is largely unresponsive to currently available chemotherapeutic drugs. The development of more effective therapies would be aided by better preclinical models.
Methods: An in vitro multicellular gastric cancer spheroid model was established using the liquid overlay technique and compared with the corresponding xenografts in immunodeficient mice.
Results: Twelve of 17 (71%) gastric cancer cell lines reflected growth characteristics of their parental gastric carcinomas in three-dimensional culture. Thus, cell lines derived from peritoneal and pleural carcinomatosis grew as single cells (HSC-39, KATO-II, KATO-III) and cell aggregates (SNU-5, SNU-16). Cell lines representing adenosquamous (MKN-1) and tubular differentiation (MKN-28, MKN-74, N87) formed partly compact multicellular spheroids recapitulating the tumor architecture of the respective original tumor. The differentiated phenotype was lost after subcutaneous implantation of the in vitro spheroids in mice. The degree of morphologic differentiation was reflected by the levels of mucin and constitutive E-cadherin expression. Heterogeneous changes of other adhesion molecules (EpCAM, alpha2beta1, CD44s, Le(x), sLe(x)) were observed. In contrast, cell lines derived from poorly differentiated gastric carcinomas (Hs-746T, RF-1, RF-48) formed fully compact spheroids mimicking the poorly differentiated phenotype, were E-cadherin negative, and showed only CD44s up-regulation.
Conclusions: Recapitulating some complexity of their in vivo counterparts, multicellular gastric cancer spheroids may represent a physiologically valid model for studying the biology of this cancer, and testing new therapeutic strategies.