Increased Tumor-Initiating Frequency and Morphological Aspects of RN5-SOhigh EGFP(+) Cell-Derived Tumors in Syngeneic C57Bl/6J Mice
RN5-SOlow and RN5-SOhigh cells were injected i.p. in C57Bl/6J mice at three doses (500,000, 50,000, and 5,000 cells) and killed after 8, 11, and 13 weeks, respectively.
(A) Fraction of mice with tumors found by microscopic analyses. At all injected doses of RN5 cells and time points, tumor incidence is higher with RN5-SOhigh cells. The tumor-initiating frequency (TIF) was calculated for both groups.
(B–F) H&E-stained sections. (B) Tumor of RN5-SOhigh cells (500,000 cells at 8 weeks); tumor cells are located subcutaneously in the parietal wall. (C) Intramuscular tumor in the abdominal wall of the same mouse. (D) In the same group (500,000 cells at 8 weeks), tumor cell growth on the liver surface. (E) and (F) Intramuscular tumors in a mouse (50,000 RN5-SOhigh cells at 8 weeks).
(G) A parallel section of the one presented in (F) shows a Goldner staining to better emphasize the muscle tissue (red) and the connective tissue (green) in the tumor mass. Arrows in (F) and (G) indicate muscle fibers. See also Figure S3.