aee-788 and Colonic-Neoplasms

Combinatorial therapies that target multiple signaling pathways may provide improved therapeutic responses over monotherapies. In the present study, we evaluated the effect of celecoxib and AEE788 alone and in combination on cell proliferation, invasion, migration, angiogenesis, morphological changes, actin filament organization and apoptosis induction in the human colon cancer cell lines.. Effect of celecoxib and AEE788 alone and in combination on colon cancer cell lines was evaluated by cell proliferation assay, morphological analysis, cell cycle analysis, scratch-wound healing and chorioallantoic membrane assays, zymography, nuclear fragmentation and western blot analyses.. Either drug alone or in combination inhibited human colonic adenocarcinoma cell lines HCT 15 and HT 29 in a dose-dependent manner. Microscopic analysis revealed inhibition of cell membrane extensions, cell shrinkage, and disorganization of actin filaments. Additionally, either drug alone or in combination inhibited HCT 15 migration, invasion and angiogenesis by suppressing matrix metalloproteinase-2 and -9 activities. Increased reactive oxygen generation, loss of mitochondrial membrane potential, cleavage of PARP, caspase-3 activation and DNA ladder formation characterized the induction of apoptosis by celecoxib and/or AEE788 treatment. Either drug individually induced apoptosis via down-regulation of the anti-apoptotic proteins Bcl(2) and Bcl-x(L), and up-regulation of pro-apoptotic protein Bax, cleavage of PARP, activation of caspase-3 and inhibition of vascular endothelial growth factor receptor signaling pathways.. Results indicate that AEE788 potentiates celecoxib-mediated inhibition of proliferation and angiogenesis in HCT 15 colon cancer cells and may prove useful for developing a combinatorial therapy for colon cancer.

Topics: Actins; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Celecoxib; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Chickens; Colonic Neoplasms; Cyclooxygenase 2 Inhibitors; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Purines; Pyrazoles; Reactive Oxygen Species; Sulfonamides

Analysis of changes in cancer cell morphology and cytoskeletal element induced by external stimuli is focus of current cancer chemotherapeutic studies. Cancer cell cytoskeleton is complex network of interwoven protein fibers composed of microtubules, microfilaments and intermediate filaments. These interwoven protein fibers are responsible for maintaining cell morphology, movement, adhesion and transmembrane signal transmission. In this study, morphological and cytoskeletal changes induced by AEE788 and/or Celecoxib on colon cancer cell HCT 15 were analyzed using advanced microscopic techniques. Cell proliferation assay was used for determining IC(50) of AEE788 and/or Celecoxib on HCT 15. Confocal microscopic analysis of AEE788 and/or Celecoxib treated HCT 15 was performed using Rhodamine-Phalloidin (actin stain) and Hoechst 33342 (nuclear stain). Atomic force (AFM) and scanning electron microscopic (SEM) studies were also performed to analyze cell morphology and cell wall extension (filopodia and lamellipodia). In addition, quantitative analysis of morphological parameters was studied using cellular image processing technique. This is the first report that combination of AEE788 and Celecoxib additively increase growth inhibition and cell death on human colon cancer cell HCT 15 as estimated by cell proliferation assay. Morphological analysis of AEE788 or Celecoxib treated HCT 15 cell for 24h have not revealed significant change in morphology under phase contrast microscopy. But, slight morphological changes were observed in combination (AEE788+Celecoxib) treated HCT 15 for 24h. In contrast, high resolution confocal laser fluorescence and atomic force microscopic studies have revealed cell shrinkage, disorganized actin filament and, loss of filopodia and lamellipodia. These changes were more prominent in combination of AEE788 and Celecoxib treated HCT 15 than either drug alone. These results may suggest antiproliferative and antimetastatic activity of AEE788 and/or Celecoxib. Quantitative analysis of morphological parameters using cellular image processing technique have shown decrease in mean area, perimeter, compactness and eccentricity of combination drug treated cells than either drug alone. These results further support the confocal and AFM study. Scanning electron microscopic study of AEE788 and/or Celecoxib treated HCT 15 has also shown morphological changes and loss of filopodia and lamellipodia. In conclusion, this investigation of morphological a

Topics: Antineoplastic Agents; Celecoxib; Cell Shape; Colonic Neoplasms; Cytoskeleton; Epithelial Cells; Humans; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Purines; Pyrazoles; Sulfonamides

Immunohistochemical analysis of human colon cancers growing in the cecal walls of nude mice revealed that epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor 2 (VEGFR2) were expressed by different tumor cells and tumor-associated endothelial cells, whereas platelet-derived growth factor receptor (PDGFR)beta was expressed by tumor-associated endothelial cells and pericytes. We hypothesized that treatment of nude mice with AEE788 (an inhibitor of EGFR and VEGFR phosphorylation) and STI571 (an inhibitor of PDGFRbeta phosphorylation) combined with irinotecan would overcome the intratumoral heterogeneity of these growth factors and efficiently inhibit colon cancer growth and metastasis. We implanted HT29 and KM12SM cells into the cecal walls of nude mice. Two weeks later, the mice were treated with oral vehicle solution; oral AEE788, oral STI571, or intraperitoneal injection of irinotecan as single agents; or the various combinations of these agents. We then assessed the mice for tumor growth and metastasis. Immunohistochemical analyses revealed that oral AEE788 suppressed proliferation and increased apoptosis of tumor cells and tumor-associated endothelial cells. Oral STI571 increased apoptosis of tumor-associated endothelial cells and pericytes. The combination of AEE788, STI571, and irinotecan produced the greatest inhibition of primary tumor growth and metastasis. Collectively, these data demonstrate that only targeting multiple tyrosine kinase receptors on colon cancer cells and tumor-associated stromal cells can overcome the effects of biologic heterogeneity for resistance to treatment and has the potential to improve therapeutic outcome for patients with this disease.

Topics: Animals; Apoptosis; Benzamides; Cell Line, Tumor; Colonic Neoplasms; ErbB Receptors; Humans; Imatinib Mesylate; Immunohistochemistry; Ki-67 Antigen; Lymphatic Metastasis; Male; Mice; Mice, Nude; Piperazines; Platelet Endothelial Cell Adhesion Molecule-1; Purines; Pyrimidines; Receptor, Platelet-Derived Growth Factor beta; Receptors, Vascular Endothelial Growth Factor; Stromal Cells

The purpose of our study was to determine whether the dual inhibition of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) signaling pathways in tumor-associated endothelial cells can inhibit the progressive growth of human colon carcinoma in the cecum of nude mice. SW620CE2 human colon cancer cells growing in culture and orthotopically in the cecum of nude mice expressed a high level of transforming growth factor alpha (TGF-alpha) and vascular endothelial growth factor (VEGF) but were negative for EGFR, human epidermal growth factor receptor 2 (HER2), and VEGFR. Double immunofluorescence staining revealed that tumor-associated endothelial cells expressed EGFR, VEGFR2, phosphorylated EGFR (pEGFR), and phosphorylated VEGFR (pVEGFR). Treatment of mice with either 7H-pyrrolo [2,3-d]-pyrimidine lead scaffold (AEE788; an inhibitor of EGFR and VEGFR tyrosine kinase) or CPT-11 as single agents significantly inhibited the growth of cecal tumors (P < .01); this decrease was even more pronounced with AEE788 combined with CPT-11 (P < .001). AEE788 alone or combined with CPT-11 also inhibited the expression of pEGFR and pVEGFR on tumor-associated endothelial cells, significantly decreased vascularization and tumor cell proliferation, and increased the level of apoptosis in both tumor-associated endothelial cells and tumor cells. These data demonstrate that targeting EGFR and VEGFR signaling on tumor-associated endothelial cells provides a viable approach for the treatment of colon cancer.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Cecal Neoplasms; Cell Line, Tumor; Colonic Neoplasms; Endothelial Cells; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Humans; Irinotecan; Male; Mice; Mice, Nude; Neoplasm Proteins; Phosphorylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Purines; Signal Transduction; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2; Xenograft Model Antitumor Assays

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.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Colonic Neoplasms; Endothelial Cells; Humans; Lymphatic Metastasis; Male; Mice; Mice, Nude; Neoplasm Metastasis; Purines; Receptor Protein-Tyrosine Kinases

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.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Cell Growth Processes; Colonic Neoplasms; ErbB Receptors; Growth Substances; HT29 Cells; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Irinotecan; Male; Mice; Mice, Nude; Neoplasm Metastasis; Phosphorylation; Platelet Endothelial Cell Adhesion Molecule-1; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Purines; Receptors, Growth Factor; Receptors, Vascular Endothelial Growth Factor; Xenograft Model Antitumor Assays