Kenji Yokoi

University of Texas MD Anderson Cancer Center, Houston, TX, United States

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Publications (15)84.02 Total impact

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    ABSTRACT: There is growing evidence implicating that neutrophil gelatinase-associated lipocalin (NGAL) plays a role in the development and progression of cancers. However, the effect of NGAL in colorectal carcinoma (CRC) has not been clearly elucidated. In this study, we investigated the role of NGAL in the tumorigenesis and progression of CRC and evaluated the clinical value of NGAL expression. We examined NGAL expression in 526 colorectal tissue samples, including 53 sets of matched specimens (histologically normal mucosa, adenomas, and carcinomas) using immunohistochemical analysis. In CRCs, correlations between NGAL expression and clinicopathologic parameters were analyzed, and survival analysis was conducted. The role of NGAL was further tested using mouse xenograft models. NGAL expression was elevated during the colorectal adenoma-carcinoma sequence both among the 526 cases (r(s) = 0.66, P < 0.001) and in the 53 sets of matched specimens (r(s) = 0.60, P < 0.001). In CRCs, NGAL expression was associated with cancer stage (P = 0.041) and tumor recurrence in stage II patients (P = 0.037). Survival analysis revealed that NGAL expression was an independent prognostic factor for overall survival (HR = 1.84, P = 0.004) and for disease-free survival of stage II patients (HR = 5.88, P = 0.021). In mouse models, the xenografts in cecum and spleen were heavier and more numerous in the group injected with NGAL-overexpressing CRC cells (P < 0.05). NGAL overexpression may promote the tumorigenesis and progression of CRC. Detecting NGAL expression in tumor tissues may be useful for evaluating prognosis of patients with CRC.
    Clinical Cancer Research 05/2011; 17(13):4331-40. · 7.84 Impact Factor
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    ABSTRACT: There is an urgent need to develop novel markers of pancreatic cancer to facilitate early diagnosis. Pancreatic carcinoma is characterized by marked stroma formation with a high number of infiltrating tumor-associated macrophages (TAMs) that originate from circulating mononuclear cells (MNCs). We hypothesized that differential analysis of protein expression and phosphorylation in circulating MNCs from healthy nude mice and nude mice bearing orthotopic human pancreatic cancer would identify a surrogate marker of pancreatic cancer. These differences were analyzed by two-dimensional gel electrophoresis followed by Western blot analysis using antibody against phosphorylated tyrosine proteins (pY). Protein and phosphorylated protein spots of interest were identified by mass spectrometry and validated by Western blot analysis as candidate markers for pancreatic cancer. We found that the expression and phosphorylation of Src family proteins were significantly higher in circulating MNCs from mice bearing pancreatic cancer than in circulating MNCs from healthy mice. TAMs in mice with pancreatic tumors also had higher Src family protein expression and phosphorylation than resident macrophages in the pancreas of healthy mice. The expression and phosphorylation of Src family proteins were correlated with tumor weight; however, increased Src expression and phosphorylation also occurred in MNCs from mice with chronic pancreatitis. This is the first report to explore novel pancreatic tumor markers in circulating MNCs. Although the specificity of the marker for pancreatic cancer was low, it could be used to monitor the disease or to select high-risk patients with chronic pancreatitis.
    Translational oncology 01/2011; 4(2):83-91. · 3.40 Impact Factor
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    ABSTRACT: Experimental metastases in the brain of mice are infiltrated by microglia, and parabiosis experiments of green fluorescent protein (GFP(+)) and GFP(-) mice revealed that these microglia are derived from circulating monocytes (GFP(+), F4/80(+), and CD68(+)). These findings raised the question as to whether microglia (specialized macrophages) possess tumoricidal activity. C8-B4 murine microglia cells were incubated in vitro in medium (control) or in medium containing both lipopolysaccharide and interferon-γ. Control microglia were not tumoricidal against a number of murine and human tumor cells, whereas lipopolysaccharide/interferon-γ-activated microglia lysed murine and human tumor cells by release of nitric oxide. Parallel experiments with murine peritoneal macrophages produced identical results. Neither activated microglia nor activated macrophages lysed nontumorigenic murine or human cells. Collectively, these data demonstrate that brain metastasis-associated microglia are derived from circulating mononuclear cells and exhibit selective and specific tumoricidal activity.
    Translational oncology 01/2010; 3(6):380-8. · 3.40 Impact Factor
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    ABSTRACT: The major cause of death from cancer is metastases that are resistant to conventional therapies. Metastases can be located in different organs and in different regions of the same organ that influence the response to therapy. Primary tumor in general and metastatic lesions in particular are biologically heterogeneous and contain multiple cell populations with diverse characteristics of growth rate, karyotype, cell surface receptors, antigenicity, immunogenicity, enzymes, hormone receptors, sensitivity to different cytotoxic drugs, production of extracellular matrix proteins, adhesion molecules, angiogenic potential, invasiveness, and metastatic potential. The outcome of metastasis depends on multiple interactions of metastatic cells with homeostatic mechanisms, which tumor cells often usurp. At the primary metastatic sites, tumor cells interact with host cells, such as endothelial cells, pericytes, epithelial cells, fibroblasts, myoepithelial cells, and leukocytes. The tissues composed by these normal cells are biologically unique, and the organ microenvironments they provide for tumor cells are also unique. The pathogenesis of a metastasis consists of many sequential steps that must be completed to produce clinically relevant lesions. Preferential metastasis of tumor cells to certain organs is independent of vascular anatomy, rate of blood flow, and number of tumor cells delivered to each organ. The outcome of metastasis depends on multiple continuous interactions between unique subpopulations of tumor cells (“seed”) and specific host factors within the organ microenvironment, such as vasculature (“soil”). Understanding the mechanisms responsible for the development of biological heterogeneity in primary cancers and metastases, and the processes that regulate tumor cell dissemination to and proliferation in distant tissues, is a major goal of research. For many years, all of our efforts to treat cancer metastases have concentrated on the inhibition or destruction of tumor cells. Because all cells in the body depend on an adequate supply of oxygen and nutrients, and on the ability of the circulatory system to remove toxic molecules, therapeutic regimens directed against tumor-associated endothelial cell can destroy tumor cells regardless of their biologic heterogeneity. New strategies to treat tumor cells by modulating their interaction with the organ microenvironment and by targeting receptors expressed on tumor-associated endothelial cells present unprecedented possibilities for the treatment of cancer metastasis.
    01/2008;
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    ABSTRACT: Oral treatment with the dual-receptor tyrosine kinase inhibitor AEE788 effectively reduces the number of peritumoral lymphatic vessels and the incidence of lymph node metastasis in nude mice with human HT29 colon cancer cells growing in the cecum. Whether inhibition of lymph node metastasis in colon cancer can be achieved by directly targeting lymphatic endothelial cells remains unclear. Using a microsurgical approach, we generated conditionally immortalized lymphatic endothelial cell lines from the H-2K(b)-tsA58 mouse mesentery and characterized these cells for the expression of lymphatic endothelial cell markers. Lymphatic endothelial cells were stimulated in culture with an array of tumor cell-produced cytokines, leading to the identification of redundant pathways for proliferation and survival. Treatment with AEE788 decreased the migration, proliferation, and survival of lymphatic endothelial cells, demonstrating that oral treatment with AEE788 effectively decreases the incidence of colon cancer lymphatic metastasis due, in part, to the direct inhibition of lymphatic endothelial cell signaling.
    Neoplasia (New York, N.Y.) 10/2006; 8(9):747-57. · 5.48 Impact Factor
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    ABSTRACT: Androgen-independent prostate cancer (PCa) may be susceptible to modulation of the tumor microenvironment. We determined whether a dual tyrosine kinase inhibitor (AEE788) of the epidermal growth factor receptor (EGF-R) and vascular endothelial growth factor receptor (VEGF-R) combined with chemotherapy can produce therapy of human PCa in nude mice. PC-3MM2 human PCa cells were injected into the prostate of nude mice. Three days later, the mice were randomized into four groups: saline control, paclitaxel, AEE788, and AEE788 and paclitaxel. The mice were treated for 5 weeks and necropsied. Tumor incidence, weight, and incidence of lymph node metastasis were recorded. Tumor tissue was analyzed immunohistochemically. Treatment of mice with AEE788 or AEE788 plus paclitaxel significantly decreased tumor incidence, total tumor weight, and incidence of lymph node metastasis. AEE788 treatment alone or in combination with paclitaxel inhibited the phosphorylation of EGF-R and VEGF-R on tumor cells and tumor-associated endothelial cells. Therapeutic efficacy correlated with an increase in apoptosis of tumor cells and tumor-associated endothelial cells. Blockade of EGF-R and VEGF-R signaling pathways coupled with chemotherapy suppressed the progressive growth and metastasis of human PCa cells growing orthotopically in nude mice.
    The Prostate 12/2005; 65(3):203-15. · 3.84 Impact Factor
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    ABSTRACT: Although gemcitabine has been approved as the first-line chemotherapeutic reagent for pancreatic cancer, its response rate is low and average survival duration is still only marginal. Because epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR) modulate tumor progression, we hypothesized that inhibition of phosphorylation of all three on tumor cells, tumor-associated endothelial cells, and stroma cells would improve the treatment efficacy of gemcitabine in an orthotopic pancreatic tumor model in nude mice and prolong survival. We implanted L3.6pl, a human pancreatic cancer cell, in the pancreas of nude mice. We found that tumor-associated endothelial cells in this model highly expressed phosphorylated EGFR, VEGFR, and PDGFR. Oral administration of AEE788, a dual tyrosine kinase inhibitor against EGFR and VEGFR, decreased phosphorylation of EGFR and VEGFR. PDGFR phosphorylation was inhibited by STI571. Although i.p. injection of gemcitabine did not inhibit tumor growth, its combination with AEE788 and STI571 produced >80% inhibition of tumor growth and prolonged survival in parallel with increases in number of tumor cells and tumor-associated endothelial cell apoptosis, decreased microvascular density, decreased proliferation rate, and prolonged survival. STI571 treatment also decreased pericyte coverage on tumor-associated endothelial cells. Thus, inhibiting phosphorylation of EGFR, VEGFR, and PDGFR in combination with gemcitabine enhanced the efficacy of gemcitabine, resulting in inhibition of experimental human pancreatic cancer growth and significant prolongation of survival.
    Cancer Research 11/2005; 65(22):10371-80. · 8.65 Impact Factor
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    ABSTRACT: We screened an orthotopic nude mouse model of human pancreatic cancer for candidate serum biomarkers and examined their presence in the plasma of pancreatic cancer patients. Nude mice were injected in the pancreas with L3.9pl human pancreatic cancer cells. One week later, the mice were randomized into 4 treatment groups: i) control, saline; ii) oral STI 571; iii) intraperitoneal gemcitabine; and iv) STI 571 and gemcitabine. After 1, 2, and 3 weeks of treatment, sera and tumors were collected from mice in each group as well as uninjected mice. All sera were analyzed by surface enhanced laser desorption ionization mass spectrometry using ProteinChip technology. Protein profiles were analyzed with the Biomarker Wizard software package. The concentration of candidate proteins was evaluated in mouse sera and plasma from 135 pancreatic cancer patients, 7 pancreatitis patients, and 113 healthy volunteers. The combination therapy inhibited tumor growth. A 11.7-kDa protein peak correlating with tumor weight was purified by gel filtration, separated by SDS-PAGE, and identified as mouse serum amyloid A (SAA) by amino acid sequencing and public database searches. The expression of SAA in mouse sera was confirmed by Western blotting and correlated with tumor weight. The level of SAA in plasma of pancreatic cancer patients correlated with clinical stage and was significantly higher than in normal volunteers (mean value: 180.1 microg/ml vs 27.9 microg/ml: P<0.01) or pancreatitis patients. For SAA used as a single tumor marker with a cut-off of 75 microg/ml, the sensitivity for pancreatic cancer was 96.5% and specificity was 31.9%. Our search for specific marker proteins to identify pancreatic cancer was unsuccessful. Although SAA is not specific for pancreatic cancer and not sensitive enough to detect stage I patients, it may be a candidate biomarker for detecting and monitoring the progressive growth of pancreatic cancer.
    International Journal of Oncology 11/2005; 27(5):1361-9. · 2.66 Impact Factor
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    ABSTRACT: Although gemcitabine has been accepted as the first-line chemotherapeutic reagent for advanced pancreatic cancer, improvement of response rate and survival is not sufficient and patients often develop resistance. We hypothesized that the inhibition of phosphorylation of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) on tumor cells and tumor-associated endothelial cells, combined with gemcitabine, would overcome the resistance to gemcitabine in orthotopic pancreatic tumor animal model. L3.6pl, human pancreatic cancer cells growing in the pancreas, and tumor-associated endothelial cells in microorgan environment highly expressed phosphorylated EGFR, VEGFR, and Akt, which regulates antiapoptotic mechanism. Oral administration of AEE788 (dual tyrosine kinase inhibitor against EGFR and VEGFR) inhibited the phosphorylation of EGFR, VEGFR, and Akt on tumor-associated endothelial cells as well as tumor cells. Although intraperitoneal (i.p.) injection of gemcitabine showed limited inhibitory effect on tumor growth, combination with AEE788 and gemcitabine produced nearly 95% inhibition of tumor growth in parallel with a high level of apoptosis on tumor cells and tumor-associated endothelial cells, and decreased microvascular density and proliferation rate. Collectively, these data indicate that dual inhibition of phosphorylation of EGFR and VEGFR, in combination with gemcitabine, produces apoptosis of tumor-associated endothelial cells and significantly suppresses human pancreatic cancer in nude mice.
    Neoplasia 08/2005; 7(7):696-704. · 5.47 Impact Factor
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    ABSTRACT: We determined whether the administration of the tyrosine kinase inhibitor, AEE788, which targets the epidermal growth factor receptor and the vascular endothelial growth factor receptor, alone or in combination with paclitaxel, can inhibit progressive growth of human ovarian carcinoma in the peritoneal cavity of female nude mice. Western blot analysis and immunohistochemical analysis identified the optimal dose and schedule of AEE788 therapy. In several different experiments, paclitaxel-sensitive and paclitaxel-resistant human ovarian carcinoma cells were injected into the peritoneal cavity of nude mice. Seven days later, treatment with saline (control), AEE788 alone, paclitaxel alone, or a combination of AEE788 and paclitaxel began and continued for 45 days when the mice were necropsied. In independent survival experiments, the mice were necropsied when they became moribund. Oral administration of AEE788 inhibited phosphorylation of the epidermal growth factor receptor and vascular endothelial growth factor receptor for up to 48 hours. Treatment with AEE788 plus paclitaxel significantly reduced tumor weight and increased survival of mice implanted with paclitaxel-sensitive cell lines compared with control mice or mice treated with AEE788 alone or paclitaxel alone. In mice implanted with paclitaxel-resistant cells, the combination therapy also significantly reduced tumor weight but did not prolong survival. The combination therapy induced apoptosis of both tumor cells and tumor-associated endothelial cells. The administration of AEE788 and paclitaxel inhibits the progression of human ovarian carcinoma in the peritoneal cavity of female nude mice, in part, by inducing apoptosis of tumor-associated endothelial cells.
    Clinical Cancer Research 08/2005; 11(13):4923-33. · 7.84 Impact Factor
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    ABSTRACT: Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter, and GABA receptors have been recently detected on epithelial colon cancer cells. Nembutal (pentobarbital) is a barbiturate with GABA-agonistic effects. We demonstrate that GABA receptors are present on colon cancer cell lines (KM12SM, HT29, RKO). Nembutal (0.1-500 microg/ml) continuous exposure resulted in an IC50 level of 58 microg/ml for the KM12SM cells and 120 microg/ml for the HT29 cells. Nembutal reduced cellular cAMP concentration in colon cancer cells and resulted in a dose and time dependent decrease in MMP-2 and MMP-9 levels. In the KM12SM intracecal injected mice, 9 of 10 mice in the metaphane group developed a primary tumor (mean weight = 2.16 g +/- 0.76) compared to 7 of 10 mice in the nembutal group (mean weight = 0.41 g +/- 0.21, p = 0.03). In the KM12SM intrasplenic injected mice, the tumor weight in the spleen was 85% smaller in the nembutal group compared to the metaphane group (p = 0.008). In the HT29 injected mice, the metaphane group and nembutal group had similar tumor incidence, but combined tumor weight (primary tumor and liver metastases) was significantly higher in the metaphane group (1.61+/- 0.45 g) versus 0.07 +/- 0.05 g; p = 0.008. The incidence of liver metastases in the nembutal group was zero compared to eight out of nine in the metaphane group. To the best of our knowledge, this is the first evidence that nembutal is a potent inhibitor of primary colon cancer and metastasis. These findings may have therapeutic implications for the treatment of colon and other cancers.
    Cancer biology & therapy 08/2005; 4(7):753-8. · 3.29 Impact Factor
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    ABSTRACT: We studied growth factors and their receptors in tumor cells and tumor-associated endothelial cells as the therapeutic targets in colon cancer. Immunohistochemical analysis of 13 surgical specimens of human colon adenocarcinoma revealed that both tumor cells and tumor-associated endothelial cells in 11 of the 13 specimens expressed the epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), EGF receptor (EGFR), phosphorylated EGFR (pEGFR), vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and phosphorylated VEGFR (pVEGFR). HT29 human colon cancer cells growing orthotopically in the cecum of nude mice expressed a high level of EGF, EGFR, pEGFR, VEGF, VEGFR, and pVEGFR. Double-immunofluorescence staining found that tumor-associated mouse endothelial cells also expressed pEGFR and pVEGFR. Tumors in mice treated for 5 weeks with oral AEE788 (an inhibitor of EGFR and VEGFR tyrosine kinase) as a single agent or with CPT-11 alone were smaller (>50%) than those in control mice. Mice treated with the combination of AEE788 and CPT-11 had significantly smaller tumors (P < 0.01) and complete inhibition of lymph node metastasis. AEE788 alone or in combination with CPT-11 inhibited pEGFR, pVEGFR, and phosphorylated Akt expression on tumor-associated endothelial cells as well as on tumor cells. The combination therapy also significantly decreased microvessel density and tumor cell proliferation and increased the level of apoptosis in both tumor cells and tumor-associated endothelial cells. Collectively, these data suggest that the dual inhibition of EGFR and VEGFR signaling pathways in tumor cells and tumor-associated endothelial cells in combination with chemotherapy can provide a new approach to the treatment of colon cancer.
    Cancer Research 05/2005; 65(9):3716-25. · 8.65 Impact Factor
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    ABSTRACT: Pancreatic adenocarcinoma is currently the fourth leading cause of cancer death in the United States, and most pancreatic cancers develop locally advanced disease or metastasis at the time of diagnosis. The mechanisms by which it invades and metastasizes are not known. To identify the genes involved in pancreatic cancer metastasis, we analyzed the gene expression profiles between highly metastatic Colo357L3.6pl and parental Colo357FG pancreatic cancer cell lines using cDNA microarrays and confirmed differential gene expression by reverse transcription-PCR, Western blotting, and immunologic analysis of 54 samples from pancreatic cancer patients. The correlation with clinical outcome was also examined. The possible signaling pathways involved with tropomyosin-related kinase B (TrkB) were analyzed. Our findings showed that TrkB was overexpressed in the highly metastatic Colo357L3.6pl cells, which correlated with perineural invasion (P = 0.026), positive retroperitoneal margin (P = 0.0005), and shorter latency to development of liver metastasis (Cox proportional hazard ratio, 0.3; 95% confidence interval, 0.1-0.8; P = 0.01) in patient samples. Extracellular signal-regulated kinases 1 and 2 were activated and Elk-1 and AP-1 DNA binding activity was induced in Colo357L3.6pl cells. Furthermore, interleukin 8 and vascular endothelial growth factor were more strongly expressed in Colo357L3.6pl than Colo357FG cells, and these findings were confirmed in Colo357L3.6pl and Colo357FG orthotopic tumors. These results suggest that overexpression of TrkB and activation of mitogen-activated protein kinase and AP-1, which may in turn induce the expression of vascular endothelial growth factor and interleukin 8, may mediate the cardinal clinical features of locally aggressive growth and metastasis of pancreatic cancer. Our results also imply that TrkB receptor may be a novel therapeutic target for pancreatic cancer.
    Clinical Cancer Research 02/2005; 11(2 Pt 1):440-9. · 7.84 Impact Factor
  • Kenji Yokoi, Isaiah J Fidler
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    ABSTRACT: Hypoxia, frequently found in the center of solid tumor, is associated with resistance to chemotherapy by activation of signaling pathways that regulate cell pro-liferation, angiogenesis, and apoptosis. We determined whether hypoxia can increase the resistance of human pancreatic carcinoma cells to gemcitabine-induced apoptosis by activation of phosphatidylinositol 3'-kinase (PI3K)/Akt, MEK/mitogen-activated protein kinase (extracellular signal-regulated kinase) [MAPK(Erk) kinase (MEK)], and nuclear factor kappa B (NF-kappa B) signaling pathways. We evaluated the phosphorylation of Akt and MAPK(Erk), DNA binding activity of NF-kappa B, and apoptosis induced by gemcitabine in L3.6pl human pancreatic cancer cells under normoxic and hypoxic conditions. We then examined the effects of the PI3K inhibitor LY294002, MEK inhibitor U0126, and the epidermal growth factor receptor tyrosine kinase inhibitor PKI 166 on these signaling pathways and induction of apoptosis. Hypoxic conditions increased phosphorylation of Akt and MAPK(Erk) and NF-kappa B DNA binding activity in L3.6pl cells. The activation of Akt and NF-kappa B was prevented by LY294002, whereas the activity of MAPK(Erk), but not NF-kappa B, was inhibited by U0126. The increased activation of Akt, NF-kappa B, and MAPK(Erk) was inhibited by PKI 166. Under hypoxic conditions, L3.6pl cells were resistant to apoptosis induced by gemcitabine. The addition of LY294002 or PKI 166 abrogated cell resistance to gemcitabine, whereas U0126 only partially decreased this resistance. These data demonstrate that hypoxia can induce resistance of pancreatic cancer cells to gemcitabine mainly through the PI3K/Akt/NF-kappa B pathways and partially through the MAPK(Erk) signaling pathway. Because PKI 166 prevented the activation of PI3K/Akt/NF-kappa B and MAPK(Erk) pathways, the combination of this tyrosine kinase inhibitor with gemcitabine should be an effective therapy for pancreatic cancer.
    Clinical Cancer Research 05/2004; 10(7):2299-306. · 7.84 Impact Factor
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    ABSTRACT: We evaluated the expression of platelet-derived growth factor (PDGF) ligands and receptors in clinical specimens of human pancreatic adenocarcinomas and determined the therapeutic effect of STI571 (Gleevec), a protein tyrosine kinase inhibitor of PDGF receptor (PDGFR), on human pancreatic carcinoma cells growing in the pancreas and liver of nude mice. Immunohistochemical staining for PDGF-AA and -BB ligands, PDGFR-alpha and -beta, and phosphorylated PDGFR-alpha and -beta was performed on 31 specimens of human pancreatic cancer and L3.6pl human pancreatic adenocarcinoma cell line. To determine the in vivo effects of STI571, nude mice with L3.6pl cells injected into the pancreas were randomized 7 days later to receive one of the following treatments: sterile water p.o. (control), STI571, gemcitabine, or a combination of STI571 and gemcitabine. In 29 of 31 clinical specimens of human pancreatic adenocarcinoma, both tumor cells and tumor-associated endothelial cells expressed phosphorylated PDGFR-alpha and -beta. L3.6pl cells growing in culture expressed moderate amounts of PDGF-AA and little to no PDGFR-alpha or -beta, whereas L3.6pl cells growing in the pancreas of nude mice expressed a high level of PDGF and receptors. Colocalization immunohistochemical analysis demonstrated expression of activated PDGFR-beta by tumor-associated endothelial cells in both the pancreas and in liver metastases. Tumors of mice treated for 4 weeks with STI571 (50 mg/kg or 100 mg/kg p.o. daily) were slightly smaller than controls. Tumors treated with gemcitabine and STI571 (50 mg/kg) were >70% smaller than tumors in control mice and 36% smaller than those in mice treated with gemcitabine only (P < 0.0002 and P < 0.04, respectively). Combination therapy also inhibited spontaneous metastasis to the liver. Tumors from mice treated with both STI571 and gemcitabine had decreased expression of activated (phosphorylated) PDGFR-alpha and -beta, decreased mean vessel density, decreased cell proliferation, and increased apoptosis of tumor cells. Collectively, these data show that activated PDGFR on tumor cells and tumor-endothelial cells can be a novel target for therapy of pancreatic carcinoma.
    Clinical Cancer Research 12/2003; 9(17):6534-44. · 7.84 Impact Factor