Fig 2: MUC1 associates with MYC and decreased survival in the TCGA-PAAD dataset. (A) GSEA of the 163 PDAC tumors in the TCGA-PAAD/PDAC dataset for associations of MUC1 expression with the indicated HALLMARK gene signatures. (B–D) Enrichment plots for the HALLMARK INTERFERON ALPHA RESPONSE (B) HALLMARK MYC TARGETS V1 (C) and HALLMARK NOTCH SIGNALING (D) pathways, comparing MUC1-high to MUC1-low PDAC tumors in the TCGA-PAAD/PDAC dataset. (E) Probability of survival comparing MUC1-high, MYC-high (blue curve) to MUC1-low, MYC-high (red curve) PDAC tumors in the TCGA-PAAD/PDAC dataset. (F) Probability of survival comparing MUC1-high, MYC-low (blue curve) to MUC1-low, MYC-low (red curve) PDAC tumors in the TCGA-PAAD/PDAC dataset. (G) Schematic representation of MUC1-C in driving PDAC NE lineage specification. MUC1-C induces STAT1 and the type I and II IFN pathways, which are associated with KRAS mutant PDAC tumors and poor patient outcomes (9). MUC1-C also activates MYC, which is required for oncogenic mutant KRAS signaling in PDACs. Further studies are needed, at least in part, to determine whether MUC1-C independently activates STAT1 and MYC. The present data further indicate that MUC1-C integrates MYC activation with induction of the (i) OCT4, SOX2 and KLF4 pluripotency factors, (ii) BRN2, ASCL1 and AURKA NE markers, and (iii) NOTCH1/2 stemness TFs. In this way, MUC1-C promotes NE dedifferentiation, self-renewal capacity and tumorigenicity in PDAC progression.

Fig 3: MUC1-C induces expression of BRN2 and NE markers.a,b RNA-seq was performed in triplicate on LNCaP-AI/tet-MUC1shRNA cells treated with vehicle or 500 ng/ml DOX for 7 days. a The datasets were analyzed with GSEA, using the Hallmark gene signature collection. Silencing MUC1 was significantly associated with upregulation of the Androgen Response pathway. b Heatmap depicting the effects of silencing MUC1 on AR pathway genes. c LNCaP, C4-2B and LNCaP-AI cells were analyzed for BRN2 mRNA levels by qRT-PCR. The results (mean±SD of four determinations) are expressed as relative mRNA levels compared to that obtained for LNCaP cells (assigned a value of 1). d Lysates from LNCaP, C4-2B, and LNCaP-AI cells were immunoblotted with antibodies against the indicated proteins. e LNCaP-AI cells stably expressing a tet-CshRNA or tet-MUC1shRNA were treated with 500 ng/ml DOX for 7 days. BRN2 mRNA levels were analyzed by qRT-PCR. The results (mean±SD of four determinations) are expressed as relative mRNA levels compared to that obtained for DOX-treated LNCaP-AI/tet-CshRNA cells (assigned a value of 1). f LNCaP-AI/tet-CshRNA and LNCaP-AI/tet-MUC1shRNA cells were treated with vehicle or 500 ng/ml DOX for 7 days. Lysates were immunoblotted with antibodies against the indicated proteins. g LNCaP-AI cells expressing a tet-CshRNA or tet-MUC1shRNA were treated with 500 ng/ml DOX for 7 days. ASCL1 (left), AURKA (middle) and SYP (right) mRNA levels were analyzed by qRT-PCR. The results (mean±SD of five determinations) are expressed as relative mRNA levels compared to that obtained for DOX-treated LNCaP/tet-CshRNA cells (assigned a value of 1). *p < 0.05 (Student’s t-test). Source data are provided as a Source Data file.