qRT-PCR. Whole-tumor RNA was harvested with an RNeasy kit (QIAGEN), and cDNA was synthesized (High Capacity; Applied Biosystems) and amplified using the murine cDNA-specific primers (Integrated DNA Technologies) listed in Supplemental Methods, along with SYBR Green Supermix (Bio-Rad). The following primers were used: MRC1 (forward: 5′ CCCTCAGCAAGCGATGTGC 3′; reverse: 5′-GGATACTTGCCAGGT CCCCA-3′); iNOS (forward: 5′-GGAGCATCCCAAGTACGAGTGG-3′; reverse: 5′-CGGCC-CACTTCCTCCAG); IL10 (forward: 5′-GGCGCTGTCATC-GATTTCTCC; reverse: 5′-GGCCTTGTAGACACCTTGGTC); Tgfb1 (forward: 5′-CGCAACAACGCCATCTATGAG; reverse: 5′-CGG-GACAGCAATGGGGGTTC); IL4 (forward: 5′-GGTCACAGGAGAAGG-GACG; reverse: 5′-GCGAAGCACCTTGGAAGCC);, IL12b (forward: 5′-GGAGTGGGATGTGTCCTCAG; reverse: 5′-CGGGAGTCCAGTC-CACCTCT); CCL3 (forward: 5′-CCACTGCCCTTGCTGTTCTTCTCT; reverse: 5′-GGGTGTCAGCTCCATATGGCG); and Rplp0 (forward: 5′-TCCTATAAAAGGCACACGCGGGC; reverse: 5′-AGACGATGT-CACTCCAACGAGGACG). Target To generate apoptotic MCF7, cells were treated in suspension with 1 μm BKM120 plus 2 μm ABT-263 (both inhibitors from Selleck Chemicals) for 4 hours, washed 5 times with PBS to remove residual drug, and used directly for efferocytosis assays or for annexin V staining. For efferocytosis coculture assays, Raw264.7-GFP cells (10 4 /well) and PyVmT or MCF7 cells (72 hours after infection with Ad.mCherry and Ad.HS-V-TK) were seeded together in a monolayer in 24-well plates in 2% FBS and cultured for 24 hours prior to the addition PBS or gancyclovir. Cells were imaged at 8, 16, and 32 h after addition of gancyclovir. Cells were collected and counted under fluorescence after 32 hours of coculture. In some experiments, Raw264.7-GFP cells (10 4 / well) were seeded in a monolayer in 24-well plates and cultured for 24 hours prior to the addition of 10 3 live MCF7-mCherry or 10 3 dead MCF7-mCherry cells in serum-free media. Where indicated in the figures, BMS-777607 (1 μm) or a neutralizing goat anti-mouse MerTK antibody (AF591, 25 μg/ml; R&D Systems)(44) was added 2 hours prior to the addition of gancyclovir or 2 hours prior to the addition of dead MCF7 cells to macrophage monolayers. Live and dead MCF7 cells were similarly seeded without Raw264.7 cells as single cultures. Media were collected after 16 hours of coculture, passed through a 0.2-μm filter, and used neat (250 μl) to quantify murine IL-10 and IL-4 by ELISA (BioLegend) according to the manufacturer's protocol. Total remaining cells were collected after 16 hours of coculture, lysed, and RNA was collected using an RNeasy kit (QIAGEN).
MethodsMice. All mice were inbred on an FVB background for more than 10 generations. WT FVB, MMTV PyVmT and MerTK -/-mice (67), originally referred to as Mer KD , were purchased from The Jackson Laboratory. Mice were genotyped by PCR of genomic DNA as previously described(30). Female virgin mice were randomized into 2 groups: (a) 1 group that remained virgin, and (b) 1 group that was bred from 42 to 44 days of age with WT male mice. Pregnancies were timed according to identification of a va...