Biomedical subjects

Daniel J Hicklin

Publications and source records attributed to Daniel J Hicklin.

76 records · Page 5Linked to original sources

PubMed2002

Activity of anti-epidermal growth factor receptor monoclonal antibody C225 against glioblastoma multiforme.

OBJECTIVE: Overexpression of epidermal growth factor receptor (EGFR) in glioblastoma multiforme (GBM) secondary to EGFR gene amplification is associated with a more aggressive tumor phenotype and a worse clinical outcome. The purpose of this study was to analyze whether blocking this receptor with the anti-EGFR chimeric monoclonal antibody C225 would decrease proliferation and increase apoptosis in GBM cells. METHODS: EGFR expression and amplification were analyzed for seven human GBM cell lines. These lines were then exposed to different concentrations of C225 for 48 hours, 72 hours, and 7 days, after which time cytotoxicity, apoptosis, and vascular endothelial growth factor expression were assessed in vitro. Two EGFR-amplified human GBM were implanted in the flanks of nude mice, and the animals received C225 twice per week intraperitoneally for 5 weeks. Tumor volumes and survival times were compared with those of sham-treated mice. RESULTS: EGFR gene amplification was demonstrated in three of the primary GBM lines. C225 treatment produced significant cytotoxicity in all three EGFR-amplified GBM lines, but not in unamplified lines. Flow cytometry demonstrated increased apoptosis in C225-treated, EGFR-amplified GBM lines, but not in unamplified lines. There was a decrease in vascular endothelial growth factor expression in all GBM lines with exposure to C225. Tumor-bearing mice treated with C225 experienced significant inhibition of tumor growth as well as a 200% increase in median survival. CONCLUSION: Blocking EGFR in GBM cells that overexpress this receptor significantly changes tumor cell biology by promoting apoptosis while decreasing proliferation and vascular endothelial growth factor expression. This approach holds great promise for the treatment of patients with GBMs.

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PubMed2002

Enhanced antitumor activity of anti-epidermal growth factor receptor monoclonal antibody IMC-C225 in combination with irinotecan (CPT-11) against human colorectal tumor xenografts.

Colon carcinomas frequently express the epidermal growth factor receptor (EGFR), and this expression correlates with more aggressive disease and poor prognosis. Previous studies have shown that EGFR blockade by monoclonal antibody IMC-C225 can inhibit the growth of human colon carcinoma tumor cells in vitro and xenografts of these tumors in athymic mice. In this report, we have studied the in vivo activity of IMC-C225 combined with the topoisomerase I inhibitor irinotecan (CPT-11) using two models of human colorectal carcinoma in nude mice. IMC-C225 was tested at a dose of 1 or 0.5 mg administered q3d. CPT-11 was administered at a dose of 100 mg/kg/week or a maximum tolerated dose of 150 mg/kg/week. Treatment with the combination of IMC-C225 (1 and 0.5 mg) and CPT-11 (100 mg/kg) significantly inhibited the growth of established DLD-1 and HT-29 tumors compared with either CPT-11 or IMC-C225 monotherapy (P < 0.05). Combination therapy with IMC-C225 (1 mg) and the MTD of CPT-11 (150 mg/kg) resulted in a regression rate of 100 and 60% of established DLD-1 and HT-29 tumors, respectively. In a refractory tumor model, combined treatment with IMC-C225 and CPT-11 significantly inhibited the growth of CPT-11 refractory DLD-1 and HT-29 tumors, whereas either agent alone did not control tumor growth. Histological examination of treated tumors showed extensive tumor necrosis, decreased tumor cell proliferation, increased tumor cell apoptosis, and a marked decrease in tumor vasculature. These results suggest that EGFR blockade by IMC-C225 combined with topoisomerase I inhibitors may be an effective therapy against chemorefractory colorectal carcinoma tumors.

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PubMed2002

Inhibition of angiogenesis by the antiepidermal growth factor receptor antibody ImClone C225 in androgen-independent prostate cancer growing orthotopically in nude mice.

In human androgen-independent prostate cancer (PCa), epidermal growth factor receptor (EGFR) regulates angiogenesis, tumor growth, and progression. In this study, we evaluated whether the blockade of EGFR by the anti-EGFR antibody ImClone C225 (IMC-C225) inhibited tumor growth and metastasis by inhibiting angiogenesis, and whether paclitaxel enhanced the results of therapy in androgen-independent PCa. PC-3M-LN4 PCa cells were implanted orthotopically in athymic nude mice and treated with i.p. IMC-C225 (1 mg twice a week) and/or paclitaxel (200 microg once a week). In vitro treatment of PC-3M-LN4 with IMC-C225 inhibited EGFR autophosphorylation without any significant antiproliferative effect. In contrast, in vivo therapy with IMC-C225 alone (P < 0.05) or in combination with paclitaxel (P < 0.005) significantly inhibited PCa growth and metastasis. Serum levels of interleukin (IL) 8 were lower after therapy, and IL-8 mRNA expression was down-regulated within the tumors after therapy. The down-regulation of IL-8 correlated with reduced microvessel density. IMC-C225 reduced tumor cell proliferation, enhanced p27(kip1) expression, and induced tumor and endothelial cell apoptosis. These studies indicate that IMC-C225 has significant antitumor effect in this murine model, mediated in part by inhibition of cellular proliferation and angiogenesis, and by enhancement of apoptosis. The simultaneous administration of paclitaxel enhanced this effect.

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PubMed2002

Anti-vascular endothelial growth factor receptor 2 antibody reduces tumorigenicity and metastasis in orthotopic prostate cancer xenografts via induction of endothelial cell apoptosis and reduction of endothelial cell matrix metalloproteinase type 9 production.

PURPOSE: Vascular endothelial growth factor (VEGF), which is produced by tumor cells, is a potent endothelial cell mitogen. The aim of the present study was to evaluate the response of orthotopic prostate cancer xenografts and prostate cancer bone metastasis to anti-VEGF receptor (flk-1) antibody (DC101) treatment. EXPERIMENTAL DESIGN: Orthotopic prostate cancer models (PC-3M-MM2 and LNCaP-LN3 prostate carcinoma cells) and a prostate cancer bone metastasis model (PC-3M-MM2) were used for these experiments. Early and established tumors were treated with saline, paclitaxel, DC101, or a DC101-plus-paclitaxel combination for 5 weeks (PC-3M-MM2) and 12 weeks (LNCaP-LN3). At the end of therapy, tumors were removed and weighed. Apoptosis, tumor cell proliferation, and angiogenesis- and metastasis-related gene expression were evaluated using immunohistochemistry, in situ hybridization, and terminal deoxynucleotidyl transferase-ediated nick end labeling (TUNEL). RESULTS: After treatment of early tumors (PC-3M-MM2), median prostate tumor weights (+/-SE) were 1230 +/- 210 mg in untreated controls, 482 +/- 121 mg in mice treated with paclitaxel (P = 0.009), 148 +/- 27 mg in mice treated with DC101 (P < 0.001), and 48 +/- 10 mg in mice treated with the combination of DC101 and paclitaxel (P < 0.001). Lymph node metastasis occurred in 7 of the 9 control mice, 5 of the 9 paclitaxel-treated animals, 5 of the 12 DC101-treated animals, and 2 of the 11 animals in the combination therapy group. Treatment with DC101 alone or in combination with paclitaxel reduced tumor-induced neovascularity measured by microvessel density and tumor cell proliferation (by proliferating cell nuclear antigen) and enhanced apoptosis (measured by TUNEL) in tumor cells and endothelial cells compared with controls. In the tibial prostate cancer metastasis model, significant inhibition of tumor growth was observed. In the LNCaP-LN3 orthotopic prostate cancer model, tumors occurred in 7 of the 10 control mice, 4 of the 10 paclitaxel-treated animals, 5 of the 10 DC101-treated animals, and 2 of the 11 animals in the combination therapy group (P < 0.05). The efficacy of DC101 was much greater in the treatment of early tumors, which suggests that tumor burden may be a critical factor in determining the response to DC101. In vitro and in vivo analysis of endothelial cell function showed reduced matrix metalloproteinase type 9 production in endothelial cells treated with DC101. CONCLUSIONS: This study confirms the principle of tumor growth inhibition by targeting angiogenesis within tumors and supports the use of anti-VEGF receptor agents.

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