Figure 1. SMYD3 loss inhibits Ras-driven pancreatic tumorigenesis.

a, Representative immunohistochemistry (IHC) images showing SMYD3 expression in cells undergoing acinar-to-ductal metaplasia (ADM, arrowheads) but not in acini (asterisk) in p48^Cre/+;Kras^+/LSL-G12D (Kras) mice. b, Smyd3 expression increases during ADM formation. Quantitative real-time-PCR (qRT-PCR) analysis of Smyd3 expression at the indicated times from control- and EGF-induced ADM ex vivo samples (four independent biological replicas). c, SMYD3 depletion inhibits ADM. Wild-type (WT, p48^Cre/+) acinar clusters (asterisk) undergo ADM and form ducts (arrowhead) ex vivo, whereas Smyd3 mutant acini explants inefficiently form ducts. d, Quantitation of acinar and ductal clusters on day 3 of culture as in (c) (four independent biological replicas with three technical replicas each). e, Schematic of the caerulein pancreatitis-induced tumorigenesis protocol¹². f, Representative hematoxylin and eosin (HE) staining and IHC for pERK1/2, a marker of Ras activity, and MUC5, a marker of PanIN lesions (arrowheads). g, Quantification of MUC5 positive lesions in caerulein-treated pancreata from Kras (n=6) and Kras;Smyd3 (n=6) mutant mice. h, Quantification of spontaneous PanIN lesions formed in 6-month old Kras (n=8) and Kras;Smyd3 (n=8) mutant mice. The grade of lesions is indicated. i, Kaplan-Meier survival of Kras;p53 mutant mice (p48^Cre/+; Kras^LSL-G12D/+;p53^lox/lox, n=33, med. survival=56 days) and Kras;p53;Smyd3 mutant mice (n=21, med. survival=68.5 days) animals. p=0.0005 by log-rank test for significance. j, Immunoblots with the indicated antibodies of Kras;p53 and Kras;p53;Smyd3 mutant pancreatic tumor lysates. Loss of SMYD3 was also confirmed by immunostaining of pancreatic sections (Extended Data Fig. 4d). All scale bars, 50 μm. *: p-value<0.05; **: p-value<0.01; n.s.: not significant. (two-tailed unpaired Student's t-test). Data are represented as mean +/− SEM.