Fig. 2.

Five days of TriCurin treatment causes a dramatic suppression of P-STAT3 in the tumor-associated macrophages (TAM). TC-1 tumor sections parallel to those used in Supplementary Fig. 1 were used to assess the levels of STAT3 and P-Tyr⁷⁰⁵-STAT3 (activated) in the Iba1+ macrophages. a, upper and middle rows, and b the Vehicle-treated mice displayed a high level of activated STAT3 (P-Y⁷⁰⁵-STAT3) in the TAM, which was suppressed by 80% (p = 1.0 × 10⁻³) in the TriCurin-treated group. This overall suppression of P-STAT3 was due to a combination of c suppression of STAT3 expression (STAT3 fluorescence normalized to HOECHST fluorescence) and d STAT3 activation (P-STAT3 normalized to STAT3). Four randomly chosen sections per mouse were used for imaging and the data (mean ± SEM) obtained from Vehicle-treated (n = 4) and TriCurin-treated (n = 4) groups. HOECHST = HOECHST33342. (Scale bar: 47.62 µm). a, lower row, absence of non-specific staining in sections treated with three 2° antibodies consecutive to one another (see “Materials and methods”)