Figure 4. TDECs accelerate H460 tumor xenograft growth and increase tumor vessel density and size.

EGFP-tagged H460 cells were maintained for 5 d under condition 3. The resulting TDECs were then mixed with a 20-fold excess of DsRed-tagged H460 tumor cells grown under standard conditions and a total of 10⁶ cells were inoculated subcutaneously into the flanks of nude mice and propagated as tumor xenografts. Control tumors consisted of the same mix of DsRed-tagged tumor cells and EGFP-tagged tumor cells propagated under standard conditions. (A) Graphical representation of tumor growth. Tumor volumes were determined at the indicated times and the averages were plotted (± SEM). The p value shown for day 17 tumor volumes was derived using a one-tailed Student’s t-test. (B) Confocal fluorescence images of frozen sections tumors from each of the two groups. Scale bar = 25 um. (C) Representative low-power hematoxylin-eosin-stained paraffin-embedded tissue sections taken from typical tumors in each of the two groups. (D) Graphical depiction of the mean number of tumor blood vessels per field (±SEM) in typical fields of each tumor type. The total number of fields examined was 32 for condition 3 tumors and 24 for standard condition tumors. Only vessels exhibiting distinct lumens and containing red blood cells, indicated by black arrows, were counted. (E) Graphical depiction of the mean blood vessel cross-sectional area (±SEM) in the two tumor types. The total number of vessels measured was 85 from standard condition tumors and 248 from condition 3 tumors. (F) The mean number of tumor blood vessels with cross-sectional areas (±SEM) that were small (30-499 um²), medium (500-1999 um²), large (2000-4999 um²), and very large (≥ 5000 um²), as measured using ImageJ software. Statistical analysis was performed using a one-tailed Student’s t test (*, p < 0.01; **, p < 0.001; ***, p < 0.0001). Similar results were obtained in two independent experiments.