Preservation of enzymatically prepared rabbit VX2 tumour cells in vitro

Establishment of successively transplantable rabbit VX2 cancer cells that express enhanced green fluorescent protein

Morphological detection of cancer cells in the rabbit VX2 allograft transplantation model is often difficult in a certain region such as serosal cavity where reactive mesothelial cells mimic cancer cells and both cells share common markers such as cytokeratins. Therefore, tagging VX2 cells with a specific and sensitive marker that easily distinguishes them from other cells would be advantageous. Thus, we tried to establish a successively transplantable, enhanced green fluorescent protein (EGFP)-expressing VX2 model. Cancer cells obtained from a conventional VX2-bearing rabbit were cultured in vitro and transfected with an EGFP-encoding vector, and then successively transplanted in Healthy Japanese White rabbits (HJWRs) (n = 8). Besides, conventional VX2 cells were transplanted in other HJWRs (n = 8). Clinicopathological comparison analyses were performed between the two groups. The success rate of transplantation was 100% for both groups. The sensitivity and specificity of EGFP for immunohistochemical detection of VX2 cells were 84.3 and 100%, respectively. No significant differences in cancer cell morphology, tumor size (P = 0.742), Ki-67 labeling index (P = 0.878), or survival rate (P = 0.592) were observed between the two. VX2 cells can be genetically altered, visualized by EGFP, and successively transplanted without significant alteration of morphological and biological properties compared to those of the conventional model.

Comparison of DMSO and glycerol as cryoprotectants for ascites tumor cells

Mouse Ehrlich ascites and rat D23 ascites tumors were stored in liquid nitrogen under identical conditions for up to 3 years. Cell viability (trypan blue exclusion) and transplantability of both tumors in animals remained virtually unaffected if preserved in 10% DMSO containing medium, whereas, cells preserved in 10% glycerol failed to produce lethal tumors in rodents.