Fig 2: The expression of mucin proteins in pigmented cells and MUCL1 expression has a negative correlation with melanin production. (a) Melanin levels in lightly pigmented (LP), moderately pigmented (MP) and darkly pigmented (DP) melanocytes, and MNT1 melanoma cells were visualized after resuspension of cell pellets. (b) Melanin levels and (c) tyrosinase activity were assessed by measuring the absorbance at 490 nm with a spectrophotometer. (d) The expression levels of mucin proteins in skin tissue from the GTEx database (N = 387, lower leg). (e) The protein‐transcripts level of MUCL1 by RNAseq was obtained from GTEx database (N = 387, lower leg). The mRNA expression levels of the mucin genes (f) muc1, (g) emcn, (h) mucl1, (i) muc4, (j) muc15 and (k) muc18 in LP, MP and DP melanocytes and MNT1 cells. The data represent three independent experiments by different melanocyte donors of NHEM or three replicates of MNT1 (mean ± SD). The expression levels of the mucin proteins (l) MUC1, (m) EMCN and (n) MUCL1. The data, produced in six independent experiments, are presented as the mean ± SD (pg mL–1). (o) The protein expression levels of mucin proteins in pigmented cells were determined by Western blot analysis (see also Figure S1). *P < 0·01 and **P < 0·001 compared with the LP group.GTEx, Genotype‐Tissue Expression consortium

Fig 3: T7-MUC1 conjugate induces tumor-specific immune responses. (A and B) Percentages of (A) CD4+/CD3+ T cells and (B) CD8+/CD3+ T cells in the total splenocytes were measured using flow cytometry. (C) Induction of cytolytic T cells in the tumor model mice was measured using a CTL assay. (D) Induction of ADCC in the tumor model mice was measured using an ADCC assay. (E and F) Representative flow cytometry results of CD8+/CD3+ T cells in splenocytes in the (E) PBS and (F) T7-MUC1 groups. Data are presented as the mean ± SD; n=8. *P<0.05 vs. PBS. MUC1, mucin 1; T7, Toll-like receptor 7 agonist; NK, natural killer; ADCC, antibody-dependent cell-mediated cytotoxicity; CTL, cytotoxic T lymphocytes.

Fig 4: Tumor-specific features were conserved in tumoroid models.a–b Paired normal, pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (AdCC) tissues were processed for organoid cultures. a Organoid growth was observed under a brightfield microscope after 2 weeks of culture in tumor-GEM. Scale bars indicate 100 µm. b Histological examination was performed via H&E staining of tissues (top) and organoids (bottom). Scale bars indicate 50 µm. c The PA-specific expression of PLAG1 was assessed in tissues (left) and organoids (right) using immunohistochemistry (IHC) staining. Paired adjacent tissues with normal histology were used as control. Nuclei were stained with hematoxylin. Scale bars indicate 50 µm. d The AdCC-specific expression of c-Kit was assessed in tissues (left) and organoids (right) using IHC staining. Paired adjacent tissues with normal histology were used as control. Nuclei were stained with hematoxylin. Scale bars indicate 50 µm. e The MEC-specific expression of MUC1 was assessed in tissues (left) and organoids (right) using IHC staining. Paired adjacent tissues with normal histology were used as control. Nuclei were stained with hematoxylin. Scale bars indicate 50 µm. f, g Tumoroids were cultured with or without the p53 inhibitor nutlin-3 (10 µM) for 5 days. Nutlin-3-sensitive (top) or -resistant (bottom) organoids were assessed for growth under a brightfield microscope f while the expression of p53 was evaluated via IHC g. Nuclei were stained with hematoxylin in IHC data. Scale bars indicate 500 µm in (f) and 50 µm in (g). h Diverse sensitivity to radiation was observed in MEC or AdCC tumoroids. Cell viability was assessed at 1, 2, 3, 5, and 10 Gy (n = 5). Cell viability of tumoroids without irradiation was normalized as 100% viability. Data are representative of at least three independent experiments. Source data are provided as a Source Data file.

Fig 5: Overview of the transcriptional regulation between YBX1 and MUC1 in lung adenocarcinoma. Activation of MUC1 promoter regions (from -1480 to -1476) by YBX1 promotes the stemness and metastasis of lung adenocarcinoma. The arrow (→) indicates direct or indirect positive regulation. The symbol (┤) indicates negative regulation.