BACKGROUND & AIMS
Induction of non-apoptotic cell death could be an approach to
eliminate apoptosis-resistant tumors. We investigated necroptosis-based
therapies in mouse models of pancreatic ductal adenocarcinoma cancer
(PDAC).
Methods
We screened 273 commercially available kinase inhibitors for
cytotoxicity against a human PDAC cell line (PANC1). We evaluated the
ability of the aurora kinase inhibitor CCT137690 to stimulate necroptosis in
PDAC cell lines (PANC1, PANC2.03, CFPAC1, MiaPaCa2, BxPc3, and PANC02) and
the HEK293 cell line, measuring loss of plasma membrane integrity, gain in
cell volume, swollen organelles, and cytoplasmic vacuoles. We tested the
effects of CCT137690 in colon formation assays, and the effects of the
necroptosis (necrostatin-1 and necrosulfonamide), apoptosis, autophagy, and
ferroptosis inhibitors. We derived cells from tumors that developed in
Pdx1-Cre;K-RasG12D/+;p53R172H/+
(KPC) mice. Genes encoding proteins in cell death pathways were knocked out,
knocked down, or expressed from transgenes in PDAC cell lines. Athymic nude
or B6 mice were given subcutaneous injections of PDAC cells or tail-vein
injections of KPC tumor cells. Mice were given CCT137690 (80 mg/kg) or
vehicle and tumor growth was monitored; tumor tissues were collected and
analyzed by immunohistochemistry. We compared gene expression levels between
human pancreatic cancer tissues (n=130) with patient survival times
using the online R2 genomics analysis and visualization platform.
Results
CCT137690 induced necrosis-like death in PDAC cell lines and reduced
colony formation; these effects required RIPK1, RIPK3, and MLKL, as well as
inhibition of aurora kinase A (AURKA). AURKA interacted directly with RIPK1
and RIPK3 to reduce necrosome activation. AURKA-mediated phosphorylation of
glycogen synthase kinase 3 beta (GSK3B) at serine 9 inhibited activation of
the RIPK3 and MLKL necrosome. Mutations in AURKA (D274A) or GSK3β
(S9A), or pharmacologic inhibitors of RIPK1 signaling via RIPK3 and MLKL,
reduced the cytotoxic activity of CCT137690 in PDAC cells. Oral
administration of CCT137690 induced necroptosis and immunogenic cell death
in subcutaneous and orthotopic tumors in mice, and reduced tumor growth and
tumor cell phosphorylation of AURKA and GSK3β. CCT137690 increased
survival times of mice with orthotopic KPC PDACs and reduced tumor growth,
stroma, and metastasis. Increased expression of AURKA and
GSK3β mRNAs associated with shorter survival
times of patients with pancreatic cancer.
Conclusions
We identified the aurora kinase inhibitor CCT137690 as an agent that
induces necrosis-like death in PDAC cells, via RIPK1, RIPK3, and MLKL.
CCT137690 slowed growth of orthotopic tumors from PDAC cells in mice, and
expression of AURKA and GSK3β associate with patient survival times.
AURKA might be targeted for treatment of pancreatic cancer.