Effects of the epidermal growth factor receptor inhibitor OSI-774, Tarceva, on downstream signaling pathways and apoptosis in human pancreatic adenocarcinoma.

Pancreatic cancer is the fifth leading cause of cancer death in North America. Gemcitabine improves the quality of life of patients but fails to significantly reduce mortality. Our laboratory has demonstrated previously that the phosphatidylinositol 3′-kinase inhibitor wortmannin promotes gemcitabine antitumor activity (S. S. W. Ng et al ., Clin. Cancer Res., 7: 3269–3275, 2001). The present study examined the effects of the epidermal growth factor receptor (EGFR) inhibitor OSI-774 (“Tarceva”) alone and in combination with wortmannin and/or gemcitabine on downstream signaling molecules, as well as apoptosis in primary pancreatic cancer xenografts implanted orthotopically in severely combined immunodeficient mice. Tumors established from two pancreatic cancer patients [Ontario Cancer Institute Pancreas number (OCIP#) 2 and OCIP#7] were treated with various combinations of the above three drugs and harvested for analyses of the following: the levels of phosphorylated and nonphosphorylated forms of EGFR, protein kinase B (PKB/Akt) and extracellular-regulated kinase (ERK1/2), and the extent of apoptosis using immunofluorescence image analysis and TUNEL assay, respectively. OSI-774 alone significantly inhibited phosphorylation of EGFR in both of the primary xenografts. Phosphorylation of pERK decreased in OCIP#2, but not in OCIP#7. No significant effects on pPKB because of OSI-774 were observed in either tumor type. The extent of apoptosis was significantly increased by 2-fold in OCIP#2 tumors treated with gemcitabine and wortmannin in combination; an additional 2-fold increase in apoptosis was evident in the presence of OSI-774. Although wortmannin failed to enhance gemcitabine-induced apoptosis in OCIP#7 tumors, the extent of apoptosis was significantly increased with the inclusion of OSI-774 in the combination. Taken together, these findings support the use of OSI-774 plus a phosphatidylinositol 3′-kinase inhibitor in combination with gemcitabine in the treatment of pancreatic cancer.

[1]  M. Kris,et al.  Efficacy of cytotoxic agents against human tumor xenografts is markedly enhanced by coadministration of ZD1839 (Iressa), an inhibitor of EGFR tyrosine kinase. , 2000, Clinical cancer research : an official journal of the American Association for Cancer Research.

[2]  L. Pustilnik,et al.  Induction of apoptosis and cell cycle arrest by CP-358,774, an inhibitor of epidermal growth factor receptor tyrosine kinase. , 1997, Cancer research.

[3]  R. Vessella,et al.  Increased AKT Activity Contributes to Prostate Cancer Progression by Dramatically Accelerating Prostate Tumor Growth and Diminishing p27Kip1 Expression* , 2000, The Journal of Biological Chemistry.

[4]  H. Friess,et al.  Overexpression of the epidermal growth factor receptor in human pancreatic cancer is associated with concomitant increases in the levels of epidermal growth factor and transforming growth factor alpha. , 1992, The Journal of clinical investigation.

[5]  M. Tsao,et al.  Wortmannin inhibits pkb/akt phosphorylation and promotes gemcitabine antitumor activity in orthotopic human pancreatic cancer xenografts in immunodeficient mice. , 2001, Clinical cancer research : an official journal of the American Association for Cancer Research.

[6]  I. Fidler,et al.  Blockade of the epidermal growth factor receptor signaling by a novel tyrosine kinase inhibitor leads to apoptosis of endothelial cells and therapy of human pancreatic carcinoma. , 2000, Cancer research.

[7]  L. Norton,et al.  Recombinant humanized anti-HER2 antibody (Herceptin) enhances the antitumor activity of paclitaxel and doxorubicin against HER2/neu overexpressing human breast cancer xenografts. , 1998, Cancer research.

[8]  L. Rosenberg.  Treatment of pancreatic cancer , 1997, International journal of pancreatology : official journal of the International Association of Pancreatology.

[9]  M. Tsao,et al.  Inhibition of phosphatidylinositide 3-kinase enhances gemcitabine-induced apoptosis in human pancreatic cancer cells. , 2000, Cancer research.

[10]  J. Downward.  Mechanisms and consequences of activation of protein kinase B/Akt. , 1998, Current opinion in cell biology.

[11]  G. Capellá,et al.  Orthotopic xenografts of human pancreatic carcinomas acquire genetic aberrations during dissemination in nude mice. , 1996, Cancer research.

[12]  J. Woodgett,et al.  Protein kinase B (c-Akt): a multifunctional mediator of phosphatidylinositol 3-kinase activation. , 1998, The Biochemical journal.

[13]  Michael J. Parsons,et al.  Protein Kinase B Regulates T Lymphocyte Survival, Nuclear Factor κb Activation, and Bcl-XL Levels in Vivo , 2000, The Journal of experimental medicine.

[14]  F. Adami,et al.  Changes of biological features in breast cancer cells determined by primary chemotherapy , 1997, Breast Cancer Research and Treatment.

[15]  R. Crowder,et al.  Glycogen Synthase Kinase-3β Activity Is Critical for Neuronal Death Caused by Inhibiting Phosphatidylinositol 3-Kinase or Akt but Not for Death Caused by Nerve Growth Factor Withdrawal* , 2000, Journal of Biological Chemistry.

[16]  H. Friess,et al.  Overexpression of HER2/neu oncogene in human pancreatic carcinoma. , 1993, Human pathology.

[17]  K. Yamaguchi,et al.  Frequent expression of genes for receptor tyrosine kinases and their ligands in human pancreatic cancer cells , 1995, International journal of pancreatology : official journal of the International Association of Pancreatology.

[18]  P. Tagliaferri,et al.  Gemcitabine combined with continuous infusion 5-fluorouracil in advanced and symptomatic pancreatic cancer: a clinical benefit-oriented phase II study , 2000, British Journal of Cancer.

[19]  M. Scheid,et al.  Dissociation of cytokine-induced phosphorylation of Bad and activation of PKB/akt: involvement of MEK upstream of Bad phosphorylation. , 1998, Proceedings of the National Academy of Sciences of the United States of America.