Blockade of leukemia inhibitory factor as a therapeutic approach to KRAS driven pancreatic cancer

Man-Tzu Wang,Frank Mccormick,Jacqueline Galeas,Nicole Fer,Jeremy Sharib,Sung Eun Kim,Eric A Collisson

doi:10.1038/s41467-019-11044-9

Abstract

KRAS mutations are present in over 90% of pancreatic ductal adenocarcinomas (PDAC), and drive their poor outcomes and failure to respond to targeted therapies. Here we show that Leukemia Inhibitory Factor (LIF) expression is induced specifically by oncogenic KRAS in PDAC and that LIF depletion by genetic means or by neutralizing antibodies prevents engraftment in pancreatic xenograft models. Moreover, LIF-neutralizing antibodies synergize with gemcitabine to eradicate established pancreatic tumors in a syngeneic, KrasG12D-driven, PDAC mouse model. The related cytokine IL-6 cannot substitute for LIF, suggesting that LIF mediates KRAS-driven malignancies through a non-STAT-signaling pathway. Unlike IL-6, LIF inhibits the activity of the Hippo-signaling pathway in PDACs. Depletion of YAP inhibits the function of LIF in human PDAC cells. Our data suggest a crucial role of LIF in KRAS-driven pancreatic cancer and that blockade of LIF by neutralizing antibodies represents an attractive approach to improving therapeutic outcomes.

Highlights

KRAS mutations are present in over 90% of pancreatic ductal adenocarcinomas (PDAC), and drive their poor outcomes and failure to respond to targeted therapies
Among all IL-6 family members, only Leukemia Inhibitory Factor (LIF) mRNA expression decreased in human PDAC cell lines in which oncogenic KRAS had been knocked down by shRNA (Supplementary Fig. 1a)
In a pan-cancer analysis, LIF expression was greater in tumor cells expressing mutant KRAS than in those expressing wild-type KRAS, whereas there was no significant difference in IL-6 expression (Fig. 1d)

Summary

Results

Oncogenic KRAS upregulates LIF through the MEK/ERK cascade. First, we evaluated whether the expression of IL-6-family cytokines is modulated by oncogenic KRAS in pancreatic cancer. Among all IL-6 family members, only LIF mRNA expression decreased in human PDAC cell lines in which oncogenic KRAS had been knocked down by shRNA (Supplementary Fig. 1a). Knocking down LIF by shRNA impaired the ability of human pancreatic cancer cell line to grow as spheres in 3D culture This phenotypic change could be rescued by the addition of LIF, but not IL-6, to the culture medium (Supplementary Fig. 2b). Knocking down LIF by shRNA repressed the tumor initiation and growth rate of human pancreatic cancer cell line in xenograft models (Supplementary Fig. 2b,c). Expression of an inducible shRNA against LIF significantly blocked the sphere-forming ability of human PDAC cells in vitro as well as tumor initiation and growth in vivo in a doxycycline-dependent manner (Fig. 3d, e). Panc2.03 (KRAS-G12D) Panc3.27 (KRAS-G12V) Panc2.13 (KRAS-Q61H) HcG-25 (KRAS-G12V)

20 RasRBD pull-down

Discussion

Methods