Figure 2. The effect of loss of CD38 on cell proliferation and cell death in late stage tumors (age matched).
Paraffin and frozen sections or protein samples were prepared from WT and Cd38‒/‒ mice injected with B16F10 cells 28 days post injection. (A-D) Effect on proliferation. Proliferation was assessed using mitotic cell count in H&E stained sections (A and B) and Ki-67 staining (C and D). (A) Representative images of H&E stained tumors grown in WT and Cd38‒/‒ mice (scale bar = 100 μm); (arrows indicate representative mitotic cells). (B) Quantitation of the number of mitotic cells. The data presented are expressed as the mean ± SEM (bars) of the number of mitotic cells in mm2 (n = 10 mice from each group). n.s = not significant, Student’s t test. (C) Representative images of Ki-67 staining of tumors grown in WT and Cd38‒/‒ mice (scale bar = 200 μm) (D) Quantitation of the number of Ki-67 positive cells. The data presented are expressed as the mean ± SEM (bars) of the percentage of Ki-67-positive cells from total cells per field (n = 6 and 5 for WT and Cd38‒/‒ mice respectively). n.s = not significant, Student’s t test. Amount of cleaved (active) caspase-3 (Casp-3) in protein extracts prepared from the tumors (E, F). (E) A representative immunoblot probed for cleaved caspase-3 and β-tubulin. Negative control (NC) and positive control (PC) proteins were prepared from MEFs untreated or treated with staurosporine respectively. (F) Quantification of cleaved caspase-3 levels. Cleaved caspase-3 level is expressed as signal-intensity values (normalized to β-Tubulin). Expression levels were significantly higher in Cd38‒/‒ mice compared with WT (*p = 0.01; Student’s t test, n = 14 for each group). (G) Representative images of active caspase-3 staining in tumors originated from WT and Cd38‒/‒ mice (scale bar = 100 µm). (H) Quantification of cleaved caspase-3 levels. The data presented are expressed as the mean ± SEM (bars) of the average number of caspase-3 positive cells per field (n = 9 mice from each group). (*p = 0.02; Student’s t test).