Induced overexpression of protein kinase D1 stimulates mitogenic signaling in human pancreatic carcinoma PANC-1 cells

J Cell Physiol. 2010 May;223(2):309-16. doi: 10.1002/jcp.22036.


Neurotensin (NT) stimulates protein kinase D1 (PKD1), extracellular signal regulated kinase (ERK), c-Jun N-terminal Kinase (JNK), and DNA synthesis in the human pancreatic adenocarcinoma cell line PANC-1. To determine the effect of PKD1 overexpression on these biological responses, we generated inducible stable PANC-1 clones that express wild-type (WT) or kinase-dead (K618N) forms of PKD1 in response to the ecdysone analog ponasterone-A (PonA). NT potently stimulated c-Jun Ser(63) phosphorylation in both wild type and clonal derivatives of PANC-1 cells. PonA-induced expression of WT, but not K618N PKD1, rapidly blocked NT-mediated c-Jun Ser(63) phosphorylation either at the level of or upstream of MKK4, a dual-specificity kinase that leads to JNK activation. This is the first demonstration that PKD1 suppresses NT-induced JNK/cJun activation in PANC-1 cells. In contrast, PKD1 overexpression markedly increased the duration of NT-induced ERK activation in these cells. The reciprocal influence of PKD1 signaling on pro-mitogenicERK and pro-apopotic JNK/c-Jun pathways prompted us to examine whether PKD1 overexpression promotes DNA synthesis and proliferation of PANC-1 cells. Our results show that PKD1 overexpression increased DNA synthesis and cell numbers of PANC-1 cells cultured in regular dishes or in polyhydroxyethylmethacrylate [Poly-(HEMA)]-coated dishes to eliminate cell adhesion (anchorage-independent growth). Furthermore, PKD1 overexpression markedly enhanced DNA synthesis induced by NT (1-10 nM). These results indicate that PKD1 mediates mitogenic signaling in PANC-1 and suggests that this enzyme could be a novel target for the development of therapeutic drugs that restrict the proliferation of these cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma / drug therapy
  • Carcinoma / enzymology*
  • Carcinoma / genetics
  • Cell Count
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Transformation, Neoplastic / drug effects
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism*
  • DNA / biosynthesis
  • DNA / drug effects
  • DNA Replication / drug effects
  • Ecdysterone / analogs & derivatives
  • Ecdysterone / pharmacology
  • Extracellular Signal-Regulated MAP Kinases / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Enzymologic / physiology
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression Regulation, Neoplastic / physiology
  • Growth Substances / genetics
  • Growth Substances / metabolism*
  • Humans
  • JNK Mitogen-Activated Protein Kinases / drug effects
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • MAP Kinase Kinase 4 / drug effects
  • MAP Kinase Kinase 4 / metabolism
  • Neurotensin / antagonists & inhibitors
  • Neurotensin / metabolism
  • Pancreatic Neoplasms / drug therapy
  • Pancreatic Neoplasms / enzymology*
  • Pancreatic Neoplasms / genetics
  • Phosphorylation / drug effects
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*


  • Growth Substances
  • Neurotensin
  • Ecdysterone
  • ponasterone A
  • DNA
  • protein kinase D
  • Protein Kinase C
  • Extracellular Signal-Regulated MAP Kinases
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 4
  • MAP2K4 protein, human