Journal: Science advances
Article Title: IGFBP2 secretion by mammary adipocytes limits breast cancer invasion.
doi: 10.1126/sciadv.adg1840
Figure Lengend Snippet: Fig. 4. IGFBP2 acts through depletion of IGF-II from the cancer microenvironment. (A) Sche- matic of the proteomics experimental setup. LC- MS/MS, liquid chromatography–tandem mass spectrometry. IP, immunoprecipitation. (B and C) Representative Western blot (B) and densitome- try analysis (C) after silencing of IGF2 (IGF-II gene) using siRNAs in MM231 cells (n = 4 biological replicates; one-sample t test; *P < 0.05 and ***P < 0.001). (D and E) Representative images (D) and quantification (E) of MM231 cell invasion in in- verted collagen/fibronectin matrices after IGF2 silencing. Scale bars, 50 μm. n = 3 biological replicates, performed in duplicate with three stacks per transwell; one-way ANOVA with Tukey correction; ***P < 0.001. (F and G) Representative images (F) and quantification (G) of MM231 cell invasion in inverted collagen/fibronectin matri- ces treated with PBS, IGF-II (10 ng/ml), IgG1κ (10 μg/ml), or anti–IGF-II (10 μg/ml). Scale bars, 50 μm. n = 3 biological replicates, performed in duplicate with three stacks per transwell; one- way ANOVA with Tukey correction; ***P < 0.001. (H and I) Representative IGF-II Western blot (H) and quantification (I) of TIF, MM231, MM468, and HCC1937 cells (n = 6 biological replicates; one- sample t test; ***P < 0.001). (J) ELISA for human IGF-II in conditioned media from TIF, MM231, MM468, and HCC1937 cells (n = 4 biological replicates; one-way ANOVA with Dunnett’s cor- rection; *P < 0.05 and ***P < 0.001). (K and L) Matrigel invasion assays for MM231 (K) and MM468 (L) cells treated with IgG1κ or anti–IGF-II (n = 3, eight fields of view (FOVs) per chamber, two to three invasion chambers per condition per replicate; two-tailed Student’s t test with Welch’s correction; **P < 0.01). Scale bars, 100 μm. (M) Schematic of the proposed mechanism for IGFBP2 inhibition of invasion through dis- ruption of breast cancer IGF-II autocrine signaling.
Article Snippet: For the exogenous protein inverse invasion screen, cells were treated with either PBS or one of the following recombinant proteins (5 μM): SPARC (R&D Systems, 941-SP), DKK1 (R&D Systems, 5439-DK), DKK3 (R&D Systems, 1118-DK), TFPI (R&D Systems, 2974-PI), TFPI2 (R&D Systems, 2545-PI), HHIP (R&D Systems, 9280-HP), PAI1 (R&D Systems, 1786-PI), IGFBP2 (R&D Systems, 674-B2), IGFBP7 (R&D Systems, 1334-B7), and GSN (Novus, H00002934-Q01).
Techniques: Liquid Chromatography with Mass Spectroscopy, Liquid Chromatography, Mass Spectrometry, Immunoprecipitation, Western Blot, Enzyme-linked Immunosorbent Assay, Two Tailed Test, Inhibition