Figure 1
hMSC migrated in tumor and promoted breast tumor growth and metastasis.
(a) Representative samples of PCR analysis showing migration and survival of hMSC. Human CYP1A1 gene, without cross-reactivity with mouse DNA, was detected by PCR analysis in tumor, blood, lymph node, spleen, liver and lung samples at 1st and 3rd day of experiment. Photomicrographs showing the presence human mitochondrial marker in the tissues (b, c). Positive signals were detected in human ESC control group (b) and in the livers of tumor-bearing mice that received hMSC (c), but no compelling evidence of positively stained cells in lung mice from the same group (d). (e) Impact of 4T1: hMSC ratio on tumor growth. All animals received 2 × 104 4T1 cells. The highest incidence of tumor growth (e) and the largest tumor volume (f–g) was seen in tumor-bearing mice that received 1 × 106 hMSC. There is a strong correlation between the number of injected hMSC and tumor volume (Fig. 1h; R2 = 0.865). (i) Semi-quantitative analysis of lung and liver tissue sections. The incidence of lung and liver metastasis was significantly higher in tumor-bearing mice that received hMSC. Combined results of 3 experiments with total of 9 animals per group (mean ± s.e.m.; *P < 0.05).
