Fig 1: SMPD2 is a downstream of ZDHHC13 to induce M2-like TAM polarization.(A) RNA-seq analysis of B16 cells with or without ZDHHC13 expression showing genes involved in LPC and SM metabolism. (B) IHC of SMPD2 in melanoma tissue array; staining quantified in ImageJ and correlated by Pearson’s analysis. (C) Analysis of survival of patients with Melanoma based on SMPD2 expression (cutoff = 50%) calculated by GEPIA2. All patients in the TCGA melanoma study were divided according to the expression level of SMPD2 (higher or lower level than median expression value of all patients). (D) Validation of Smpd2 knockdown in B16 cells, and quantification of SM and LPC levels by using Abcam SM and LPC assay kit (Abcam ab138877 and ab273332), respectively. (E–G) 2 × 105 cells generated in D in 100 μl PBS were injected into C57BL/6 mice via the tail vein. Pulmonary metastases (E and F) and lung H&E staining (E) were assessed 14 days after tumor cell injection. Mouse survival was recorded (G) (n = 6). Scale bar: 185 μm. (H) Flow cytometry analysis of ARG1+ M2-like macrophages in lungs from mice in E (n = 3). All data in this Figure are mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.001, unpaired Student’s t test.