Influence of transplantation site on metastatic ability of mouse bladder carcinoma sublines

Variation in the Incidence of Teratomas after the Transplantation of Nonhuman Primate ES Cells into Immunodeficient Mice

Embryonic stem (ES) cells have the ability to generate teratomas when transplanted into immunodeficient mice, but conditions affecting the generation remain to be elucidated. Nonhuman primate cynomolgus ES cells were transplanted into immunodeficient mice under different conditions; the number of transplanted cells, physical state (clumps or single dissociated cells), transplant site, differentiation state, and immunological state of recipient mice were all varied. The tumorigenicity was then evaluated. When cynomolgus ES cells were transplanted as clumps into the lower limb muscle in either nonobese diabetic/severe combined immunodeficiency (NOD/SCID) or NOD/SCID/?cnull (NOG) mice, teratomas developed in all the animals transplanted with 1 × 105 or more cells, but were not observed in any mouse transplanted with 1 × 103 cells. However, when the cells were transplanted as dissociated cells, the number of cells necessary for teratomas to form in all mice increased to 5 × 105. When the clump cells were injected subcutaneously (instead of intramuscularly), the number also increased to 5 × 105. When cynomolgus ES cell-derived progenitor cells (1 × 106), which included residual pluripotent cells, were transplanted into the lower limb muscle of NOG or NOD/SCID mice, the incidence of teratomas differed between the strains; teratomas developed in five of five NOG mice but in only two of five NOD/SCID mice. The incidence of teratomas varied substantially depending on the transplanted cells and recipient mice. Thus, considerable care must be taken as to tumorigenicity.

Novel enhanced lung-colonizing variant of murine MBT-2 bladder cancer cells

OBJECTIVES

To develop an enhanced lung-colonizing variant of murine bladder cancer that will allow the mechanism of metastasis to be studied more readily.

METHODS

We implanted murine bladder tumor cells (MBT-2) into the leg muscles of C3H mice. We developed variant cells from a lung metastasis nodule. We compared the MBT-2 cells and variant cells (MBT-2V) in vivo by evaluating lung nodule formation, survival, in vitro adhesion, and migration-invasion assays. Zymography and semiquantitative reverse transcriptase-polymerase chain reaction analyses were also performed to characterize the metastatic ability of both cells.

RESULTS

MBT-2 and MBT-2V cells were tumorigenic when injected intramuscularly into C3H mice, but MBT-2 cells had little potential to metastasize compared with MBT-2V cells. Metastases were observed in the lungs of mice injected in the tail vein with MBT-2 and MBT-2V cells. Mice receiving MBT-2V cells had significantly shorter survival (P <0.01) and more lung nodules (245 versus 106, P <0.0001) than those receiving MBT-2 cells. In vitro study revealed that MBT-2V cells exhibited more adhesion, greater migration, and more invasiveness than did MBT-2 cells. Pathologic examination revealed the tumors from MBT-2V cells to be more aggressive than those from MBT-2 cells. MBT-2V also showed significantly greater matrix metalloproteinase-9 expression.

CONCLUSIONS

We generated an enhanced lung-colonizing variant of MBT-2 cells. Our MBT-2V cells showed more aggressive and invasive metastatic ability than that of the MBT-2 cells. Zymography and reverse transcriptase-polymerase chain reaction analyses indicated that matrix metalloproteinase-9 might be associated with the metastatic ability of MBT-2V cells.

Effects of lipo prostaglandin E1 on distribution of cis-diamminedichloroplatinum in lung metastasis derived from Dunn osteosarcoma cell-inoculated mouse foot-pad

This study was designed to determine the effect of lipid microspheres containing prostaglandin E1 (lipo PGE1) on cis-diamminedichloroplatinum (CDDP) accumulation in primary and lung metastatic lesions. Sixty mice were divided into four groups, depending on whether or not an intra-foot-pad injection of Dunn osteosarcoma cells had been administered and on whether or not an intraperitoneal injection of lipo PGE1 had been administered. CDDP was injected intraperitoneally into all the mice 6 weeks after the inoculation. Tumor colonies of spontaneous metastases in the left lung were found in 21 out of 30 tumor-inoculated mice at autopsy. Tissue platinum concentrations in the lungs with metastatic colonies and in the foot-pad tumors were significantly higher in the lipo PGE1-administered mice than in those without treatment. Terminal deoxytransferase-mediated dUTP nick end labeling (TUNEL) assay showed marked localization of dying cells in the lung metastatic lesions of the lipo PGE1-administered mice. The results of this study showed that pretreatment with lipo PGE1 may augment the antitumor effects of CDDP at the tumor site.

Exposure to alkyllysophospholipids inhibits in vitro invasion of transitional cell carcinoma

Alkyllysophospholipids (ALP) are a group of synthetic analogs of a naturally occurring 2-lysophosphocholine. They are directly cytotoxic to a variety of neoplastic cell lines and can modulate the activation of macrophages against tumor cells. Moreover, recent reports have demonstrated the ability of racemic 1-octadecyl-2-methyl-sn-glycero-3-phosphocholine (ET-18-O-CH3) to prevent tumor cell invasion when given in noncytotoxic concentrations. Using an in vitro model, we studied the ability of ET-18-O-CH3 to prevent transitional cell carcinoma invasion. Cytostatic activity was determined by clonal growth assay (25,000 cells per plate). Suppression of colony growth was found at concentrations greater than 4 micrograms/ml. of ET-18-O-CH3 in rat and mouse transitional cell carcinoma (TCC) cell lines and greater than 2 micrograms/ml. in a human TCC line. Inhibition of tumor cell invasion was assessed by the effects on cell migration through Matrigel-coated 8 microns-pore polycarbonate filters (using 1 x 10(5) cells per chamber). Invasion was reduced to 50 to 70% of controls in both the mouse and rat TCC lines at the highest concentration (4.0 micrograms/ml.). In the human TCC line, invasion was reduced to less than 30% of controls at concentrations as low as 0.5 micrograms/ml. Motility (without invasion) of the human TCC line, as measured by cell migration through the micropore filter without the Matrigel coating, was inhibited at the same concentration of ET-18-O-CH3 found to inhibit invasion. The anti-invasive effect seen with noncytotoxic concentrations of ALP may prove useful in the treatment of transitional cell carcinoma.