miR-28 expression impairs B-cell lymphoma growth in vivo. (A) Tumor volume in NSG mice injected with Ramos BL cells expressing miR-28 or scramble RNA (control). Ramos BL cells were transduced with pTRIPZ vectors encoding miR-28 precursor sequence (blue) or scrambled control (red) sequence and induced with Dox. RFP⁺ cells isolated by flow cytometry were injected subcutaneously into either flank of NSG mice. Dox was administered in the drinking water a week before injection and throughout the experiment. Tumors were measured at the indicated times and volume was calculated as volume (mm³) = (width [mm])2 × (length [mm])/2. Each circle represents an individual tumor. (B) Representative images of miR-28 or control xenograft tumors at endpoint (top) and weight (bottom) of miR-28 or control xenograft tumors at endpoint (26 days postinjection). (C) Ramos xenografts were prepared as described in panel A. Mice were euthanized 26 days postinjection and tumors were stained with anti-Ki67, anti-caspase-3, and anti-Bcl-2. Left panels show representative micrographs. Images were acquired at ×20 (Ki67 and caspase 3; ×40 in insets) or ×40 (Bcl2) magnification. Scale bars, 100 µm (Ki67) and 50 μm (Bcl-2). Right, quantification of active caspase 3 and Bcl-2 staining. (D) Tumor volume in NGS mice injected with MD-901 ABC-DLBCL or Raji BL cells expressing miR-28 or scramble RNA (control). MD-901 ABC-DLBCL, and Raji BL cells were transduced with pTRIPZ vectors encoding miR-28 precursor sequence (blue bars) or scrambled control sequence (red bars) and induced with Dox. *P < .05; ***P < .001, unpaired Student t test.