Biomedical subjects

Isaiah J Fidler

Publications and source records attributed to Isaiah J Fidler.

82 records · Page 5Linked to original sources

PubMed2002

Multiparametric in situ mRNA hybridization analysis of gastric biopsies predicts lymph node metastasis in patients with gastric carcinoma.

We examined the expression level of several genes that regulate different steps in metastasis formation in formalin-fixed, paraffin-embedded biopsies of 189 primary human gastric carcinomas prior to surgical resection in patients in whom lymph node metastasis was not evident by endoscopic ultrasound or computed tomography (CT) scan. The expressions of epidermal growth factor receptor (EGF-R), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2 and E-cadherin were examined by a colorimetric in situ mRNA hybridization technique. The integrity of the mRNAs was verified, leaving 161 (85.2%) patients for study. After gastrectomy, 82 patients had positive lymph nodes and 79 patients had negative lymph nodes. The concurrent expression levels of MMP-2 and E-cadherin mRNAs were significantly higher and lower, respectively, in the metastatic tumors than the non-metastatic tumors. Expression of EGF-R and VEGF was not different between the metastatic and non-metastatic tumors. However, when only the intestinal-type of gastric cancer was evaluated, the level of VEGF mRNA was significantly higher in tumors associated with lymph node metastasis than in those without metastasis. However, a high MMP-2:E-cadherin ratio significantly correlated with lymph node metastasis in both types of gastric cancer. These results suggest that multiparametric in situ hybridization analysis for several metastasis-related genes may allow the preoperative prediction of lymph node metastasis from gastric cancer.

Adult↗

PubMed2002

Expression of metastasis-related genes in human epithelial ovarian tumors.

We examined the expression level of several genes that regulate distinct steps of metastasis in 55 formalin-fixed, paraffin-embedded, archival specimens of primary human ovarian carcinoma from patients undergoing curative surgery. The expression of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), basic fibroblast growth factor (bFGF), E-cadherin, type IV collagenase, matrix metalloproteinase (MMP-2 and MMP-9), and interleukin 8 (IL-8) was examined by a colorimetric in situ mRNA hybridization technique. The expression level of E-cadherin, MMP-2, MMP-9, VEGF, and IL-8 mRNA correlated with disease stages. The ratio of type IV collagenase expression (mean of the expression of MMP-2 and MMP-9) to E-cadherin expression (MMP:E-cadherin ratio) increased with increasing stage of disease (p<0.0001). Death rates significantly increased with high MMP:E-cadherin ratio (p=0.0005). Multivariate analysis of overall survival showed that the MMP:E-cadherin ratio was a significant independent prognostic factor, even after adjustment for known prognostic factors, such as histology, stage, and age.

Adult↗

PubMed2002

An orthotopic nude mouse model of oral tongue squamous cell carcinoma.

PURPOSE: Despite advances in our understanding, prevention, and treatment of head and neck squamous cell carcinoma (SCC), the 5-year survival rates for patients remain low. This poor prognosis for head and neck SCC and SCC of the oral tongue (SCCOT) in particular reflects a limited understanding of the mechanisms of local and regional metastasis, which accounts for a majority of deaths. To analyze the molecular and cellular mechanisms of metastasis, we have developed an orthotopic nude mouse model of SCCOT. EXPERIMENTAL DESIGN: Nude mice were injected submucosally in the tongue or subcutis with human squamous cell carcinoma of the oral cavity cell lines Tu159, Tu167, and MDA1986. The mice were necropsied and examined for the presence of primary tumors, and regional and systemic metastases. RESULTS: For all three of the squamous cell carcinoma of the oral cavity cell lines, tumors developed more readily in the orthotopic site, the tongue, than in the ectopic subcutis. MDA1986 cells were highly tumorigenic, particularly at the orthotopic site, with as few as 5 x 10(3) cells producing tumors in all of the mice. In contrast, s.c. tumor formation required at least 1 x 10(5) cells. The tumorigenicity observed between those mice given submucosal inoculation and those mice given s.c. inoculation (P < 0.0001). Regional metastases initially occurred in <10% of mice. To generate tumor lines of increased metastatic potential, regional metastases were isolated from cervical lymph nodes after the development of orthotopic tongue tumors. Serial passage of these lymph nodes resulted in a cell line more metastatic than its parental line. When injected into the tongues of mice, these cells metastasized to regional lymph nodes in 30% of mice and to the lungs in 20%. CONCLUSIONS: In this orthotopic murine model, oral tongue cancer recapitulates the behavior of human SCCOT, allowing for detailed studies of its biology and therapy.

Animals↗

PubMed2002

Quantitative and qualitative in vivo angiogenesis assay.

We describe the development and optimization of an in vivo angiogenesis assay utilizing gelfoam sponges impregnated with 0.4% agarose and different proangiogenic factors, such as basic fibroblast growth factor (bFGF), vascular epidermal growth factor (VEGF), tumor growth factor-alpha (TGF-alpha), and endothelial growth factor (EGF). The sponges are implanted into the subcutis of mice and harvested after different times. The gelfoam sponges are fixed, sectioned, and stained with fluorescent antibodies against CD31. The median number of CD31+ cells is determined in 10 different 0.159-mm2 fields. Proangiogenic molecules induced significant migration and proliferation of endothelial cells. To demonstrate the utility of this assay for evaluation of an antiangiogenic agent, mice were implanted with gelfoam sponges containing different proangiogenic factors and treated orally with water or PTK 787, a novel tyrosine kinase inhibitor with specific activity against the VEGF-R. PTK 787 significantly inhibited angiogenesis in sponges containing agarose + VEGF but not other proangiogenic molecules. The data show that the implanted gelfoam sponges provide a reliable quantitative assay to study in vivo angiogenesis.

Angiogenesis Inhibitors↗

PubMed2002

Synergistic therapy of human ovarian carcinoma implanted orthotopically in nude mice by optimal biological dose of pegylated interferon alpha combined with paclitaxel.

The purpose of this study was to optimize the antitumor andantiangiogenic activities of pegylated IFN-alpha (PEG-IFN-alpha)alone or in combination with paclitaxel against SKOV3ip1 human ovarian cancer cells growing orthotopically in female nude mice. Seven days after the i.p. implantation of tumor cells, groups of mice (n = 10) were injected s.c. once per week (for 4 weeks) with different doses of PEG-IFN-alpha (3,500, 7,000, 35,000, and 350,000 units). PEG-IFN-alpha at 7,000 units significantly decreased tumor incidence and volume. At doses exceeding 7,000 units, PEG-IFN-alpha was less efficacious. In another set of studies conducted 7 days after the i.p. implantation of SKOV3ip1 cells, groups of mice (n = 10) received (once per week for 4 weeks) either s.c. administrations of PEG-IFN-alpha (7,000 units), i.p. injections of paclitaxel (100 microg/wk), or a combination of PEG-IFN-alpha and paclitaxel. The mice were killed 7 days after the last treatment, and tumor burden was assessed. Administration of PEG-IFN-alpha at the optimal biological dose (7,000 units) in combination with paclitaxel significantly decreased angiogenesis and progressive growth of human ovarian carcinoma cells in a synergistic fashion. The combination therapy produced the most significant inhibition in expression of the proangiogenic molecules basic fibroblast growth factor and matrix metalloproteinase-9. Decreased microvessel density, decreased proliferating cell nuclear antigen staining, and increased endothelial cell apoptosis also correlated with therapeutic success. Collectively, the data suggest that combining the optimal biological dose of PEG-IFN-alpha with paclitaxel may provide a novel and effective approach to the treatment of human ovarian carcinoma.

Animals↗

PubMed2002

Inhibition of platelet-derived growth factor-mediated proliferation of osteosarcoma cells by the novel tyrosine kinase inhibitor STI571.

PURPOSE: Osteosarcoma is an aggressive primary bone cancer characterized by expression of platelet-derived growth factor (PDGF) and its cognate receptor. Coexpression of the growth factor and receptor suggests their role in autocrine or paracrine growth mechanisms. It has been reported previously that STI571 has specific activity in inhibiting select tyrosine kinase receptors, including PDGF and c-Kit. Osteosarcomas express low levels of c-Kit but abundant levels of PDGF receptor (PDGFR). EXPERIMENTAL DESIGN: To investigate the potential of STI571 as therapy for osteosarcoma, we studied its effects on PDGF-mediated cell growth in vitro and in an in vivo mouse model. RESULTS: PDGF acted as a potent mitogen in a dose-dependent manner in two osteosarcoma cell lines. STI571 (1.0 micro M) inhibited both PDGFR-alpha and PDGFR-beta phosphorylation and the downstream phosphorylation targets extracellular signal-regulated kinase and Akt. STI571 also inhibited PDGF-mediated growth and induced apoptosis in vitro as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase-mediated nick end labeling staining. To study the effect of STI571 alone or in combination with Taxol in an in vivo model, an osteosarcoma cell line (KRIB) was transplanted into the tibia of athymic nude mice. Mice were treated with STI571 (50 mg/kg p.o. q M-F), Taxol (8 mg/kg i.p. weekly), or STI571 plus Taxol for 6 weeks. There was no significant difference in tumor size between treatment and control mice. Aberrant signaling pathways downstream of the PDGFR in the v-Ki-ras oncogene-transformed KRIB cell line may in part explain this finding. CONCLUSIONS: Our data demonstrate that STI571 inhibits PDGF-mediated growth and leads to apoptosis of osteosarcoma cells in vitro by selective inhibition of the PDGFR tyrosine kinase. The effectiveness of STI571 in our studies suggests targeting of PDGFRs as a novel treatment for osteosarcoma.

Animals↗

PubMed2002

Blockade of the epidermal growth factor receptor signaling inhibits angiogenesis leading to regression of human renal cell carcinoma growing orthotopically in nude mice.

We determined whether blockade of the epidermal growth factor-receptor (EGF-R) signaling pathway by oral administration of the EGF-R tyrosine kinase inhibitor PKI166 can inhibit angiogenesis and growth of SN12PM6 human renal cell carcinoma (HRCC) in the kidney of nude mice and whether gemcitabine can potentiate these effects. In vitro treatment of HRCC cells with PKI166 inhibited EGF-R autophosphorylation, which correlated with a decrease in expression of Bcl-xl protein and phosphorylation of signal transducers and activators of transcription, particularly signal transducers and activators of transcription 3. PKI166 also decreased expression of vascular endothelial growth factor and basic fibroblast growth factor in a dose-dependent manner. Oral administration of PKI166 or PKI166 and injected gemcitabine or gemcitabine alone beginning 7 days after implantation of SN12PM6 cells into the kidney of athymic nude mice reduced the volume of tumors by 26, 61, and 23%, respectively. In another experiment 28 days after the orthotopic implantation of SN12PM6 cells, nephrectomy was performed followed by 4 weeks of treatment. Treatment with PKI166 and, more so, PKI166 plus gemcitabine significantly inhibited lung metastasis, corresponding to a significant increase in overall length of survival. EGF-R activation was significantly blocked by therapy with PKI166 and was associated with a significant reduction in expression of vascular endothelial growth factor and interleukin-8, decreased microvessel density, decreased staining of proliferating cell nuclear antigen, and increased tumor cell apoptosis. Collectively, the data indicate that targeting activation of EGF-R on HRCC produces significant therapeutic benefits.

Administration, Oral↗

PubMed2002

Targeted therapy against human lung cancer in nude mice by high-affinity recombinant antimesothelin single-chain Fv immunotoxin.

Several tumors, including mesothelioma and ovarian cancer, can overexpress mesothelin, a glycosylphosphatidylinositol-linked differentiation glycoprotein. The membrane-bound type of mesothelin is found in the blood of cancer patients at a very low level, which makes mesothelin a good candidate for targeted therapy of certain cancers. An antimesothelin disulfide-linked Fv (SS1 Fv) was fused to a truncated mutant of Pseudomonas exotoxin A to produce the recombinant immunotoxin SS1(dsFv)-PE38, which has a high binding affinity to mesothelin (Kd = 0.7 nM). Our studies in vitro showed that SS1(dsFv)-PE38 is significantly more cytotoxic to the high-mesothelin-producing NCI-H226 human non-small cell lung cancer cells than to human lung adenocarcinoma PC14PE6 cells, which do not express mesothelin. When administered at a nontoxic dose of 500 microg/kg on days 7, 9, and 11 to nude mice injected i.v. with the two human lung cancer cell lines, SS1(dsFv)-PE38 selectively inhibited experimental lung metastases produced by the mesothelin-producing NCI-H226 cells. Our data indicate that mesothelin-producing squamous cell carcinoma of the lung may be a good target for this immunotoxin.

ADP Ribose Transferases↗

PubMedDate not supplied

Type-1 transforming growth factor-beta differentially modulates tumoricidal activity of murine peritoneal macrophages against metastatic variants of the B16 murine melanoma.

Transforming growth factor-beta 1 (TGF-beta 1) renders mouse peritoneal macrophages tumoricidal against metastatic variants of the B16 mouse melanoma in vitro. Both direct cytotoxicity and indirect cytotoxicity were observed. A subthreshold concentration (10 U/ml) of recombinant murine interferon-gamma (rMuIFN-gamma) enhanced the direct tumoricidal activity of TGF-beta 1-activated macrophages from 29% to 88% but did not change their indirect tumoricidal profile. Data obtained from macrophages preincubated with either TGF-beta 1 or rMuIFN-gamma showed that TGF-b1 can initiate tumoricidal activity better than rMuIFN-gamma. These effects were plasma-membrane mediated because targeting macrophages with liposomal TGF-beta 1 was ineffective. The order of tumoricidal susceptibility of the B16 melanoma lines to activated macrophages was B16F1 > B16F10 > B16BL6, in inverse order of metastatic potential.

Animals↗

PubMedDate not supplied

Metastatic potential of human neoplasms.

Primary human neoplasms are heterogeneous for a large number of properties that include invasion and metastasis. The process of metastasis consists of multiple selective steps. The outcome of metastasis is determined by the continuous interaction of metastatic cells with host homeostatic mechanisms. Since the outcome of metastasis is influenced by both the intrinsic properties of the tumor cell and host factors, the successful metastatic cell must be viewed as a cell able to manipulate its new microenvironment. For many years, our efforts to treat cancer have concentrated on the destruction of tumor cells. Strategies to treat tumor cells and to modulate the host organ microenvironment should provide an additional approach for cancer treatment. Recent advancements in our understanding of the biological basis of cancer metastasis present unprecedented possibilities for translating basic research to the clinical reality of cancer treatment.

Disease Progression↗