Anti-tumor effect of CIK plus L-OHP in the human drug-resistant gastric cancer cellular peritoneal transplantation model Tumor weight and abdominal circumference were measured 21 days postinoculation (i.e., 7 days after intraperitoneal administration). The mice were sacrificed, and the number of ascites was calculated. The criterion for being cured was 60-day survival after inoculation with tumor cells. Pathomorphological observations in the human drug-resistant gastric cancer cellular peritoneal transplantation model after the treatment of L-OHP and CIK cells Tissue

sections were acquired 24 h after final injection in each group, and macroscopic observation was used to detect changes of P005091 chemical structure peritoneal transplantation nodules. The transplantation nodules in the omentum majus of each mouse were selected and divided into two sections, which were then used for routine pathological sectioning and transmission

electron microscope examination. Statistical analyses All data are expressed as mean ± SD, and buy CAL-101 analyses were carried out using SPSS 12.0 software (SPSS Inc, Chicago, IL). One-way analyses of variance (ANOVA), homogeneity tests for variance and Student’s t-tests were used for comparisons of means. A p-value less than 0.05 was considered statistically significant. Results Cell biological characteristics of OCUM-2MD3/L-OHP cells Morphological observations of drug-resistant cells As is shown in Fig.1A and 1B, the two cell types in suspension appeared round under an inverted phase contrast microscope. Following cell adhesion, cells appeared spindle-shaped, were arranged in a single layer of different sizes, and showed no significant difference in cell morphology. The microvilli on the surface of parental cells were quite abundant under a transmission electron

microscope, and the morphology of organelles in the cytoplasm was normal. The nuclei of the cells appeared abnormally large and were irregularly shaped. Moreover, euchromatin was abundant, heterochromatin was limited, and the nucleolus was large and clearly visible (Fig. 1C). There was no significant difference in morphology of drug-resistant cells compared with OCUM-2MD3 cells. (Fig. 1D). Figure 1 A. OCUM-2MD3 cell (Phase contrast microscope × 400); B. OCUM-2MD3/L-OHP L-NAME HCl cell (Phase contrast microscope × 400); C. OCUM-2MD3 cell (TEM × 5000); D. OCUM-2MD3/L-OHP cell (TEM × 5000). Growth curve and population doubling time of drug-resistant cells As shown in Fig. 2, proliferation speed of drug-resistant cells was slower than that of parental cells. The population doubling time of drug-resistant cells was 27.0 ± 2.04 h by cell counts, which extended for approximately 3 h (P < 0.05). Figure 2 Cell-growth curve of OCUM-2MD3/L-OHP. Cell cycle distribution and apoptosis of drug-resistant cells As shown in Table 1, Fig. 3 and Fig.