Fig. 3

IRIS inactivation suppresses recruitment of the IL-6R-expressing/PGE₂-secreting MSCs in an established TNBC orthotopic model. a Schematic representation of the assays performed. b The volume of orthotopic mammary tumors developed following injection of 2 × 10⁶ IRIS291 cells and at ~ 0.5 cm³ intratumorally (i.t.) injected with scrambled (dark blue, n = 5) or IRIS-pep (light blue, n = 5), or 2 × 10⁶ IRIS293 cells and at 0.5 cm³ i.t. injected with scrambled (red, n = 5) or IRIS-pep (yellow, n = 5). c The levels of circulating IL-6 (upper) or PGE₂ (lower) as detected using ELISA in mice bearing IRIS291 or IRIS293 tumors treated with scrambled or IRIS-pep. d FACS analysis of the percentage of IL-6R⁻CD90⁻, IL-6R⁻CD90⁺, IL-6R⁺CD90⁻, or IL-6R⁻CD90⁺ cells within IRIS291 treated with scrambled or IRIS-pep (upper), as well as IRIS293 treated with scrambled or IRIS-pep (lower). e Fluorescence IHC staining with CK5 (green), the MSC marker CD90 (red), and IL-6R (yellow) of the 5-μm-thick section from IRIS291 tumors treated with scrambled or IRIS-pep as per scheme shown in a. In 3`, 5`, and 9`, arrowheads denote cancer cells and arrows denote MSCs. The asterisk in 8 denotes immune cells (e.g., B cells) or red blood cells non-specific labeling with most likely a subset of secondary antibodies. Scale bars = 100 μm in 1–6 and 7–12 and 50 μm in 3`, 9`, 5`, and 11`