Biomedical subjects

A J Klein-Szanto

Publications and source records attributed to A J Klein-Szanto.

At least 19 recordsLinked to original sources

PubMed2002

Furin expression in squamous cell carcinomas of the oral cavity and other sites evaluated by tissue microarray technology.

Furin is a proprotein convertase that activates many cancer development-related substrates such as growth factors, growth factor-receptors, adhesion molecules, and matrix degrading enzymes. Furin expression was studied in sections from tissue microarrays (TMA) and conventional paraffin blocks in a collection of squamous cell carcinomas (SCC) from three different sites. A total of 118 SCCs from the oral cavity, lung and esophagus as well as 34 precursor lesions (intraepithelial neoplasia) from the oral and bronchial mucosae were studied by immunohistochemistry. Furin expression was notably higher in most precursor lesions than in normal epithelia. Tumors from either the TMAs or the conventional blocks showed significant differences when compared to the mostly negative normal epithelia. High levels of furin expression were observed in approximately 50% SCCs of three different sites as well as in precursor lesions of the oral and bronchial mucosae. In addition another 30% showed low furin expression that was localized in all tumor cells including those in a basaloid position. Normal epithelia sometimes showed low level expression but the normal basal cells were always negative. These results show that furin is up-regulated in SCCs from three different organs and validates its use as a tumor marker in both invasive and pre-invasive neoplasia.

Biomarkers, Tumor↗

PubMed2001

Furin inhibition results in absent or decreased invasiveness and tumorigenicity of human cancer cells.

Pro-protein convertases such as furin are expressed in many human tumor lines and primary tumors. Furin processes stromelysin-3, membrane type 1 matrix metalloproteinase (MMPs) involved in tumor cell invasiveness, as well as growth factors such as transforming growth factor beta1. Evaluation of furin expression in head and neck squamous cell carcinoma (HNSCC) cells exhibiting different invasive ability showed that furin overexpression correlated with their respective invasiveness. The use of a selective furin inhibitor, alpha 1-PDX (PDX) was studied in three furin-expressing invasive HNSCC cell lines. The effects of PDX transfection were evaluated in vivo and in vitro to determine changes in the malignant phenotype. Transfection of HNSCC cell lines with PDX resulted in significant decrease or absence of tumorigenicity after s.c. inoculation into severe combined immunodeficient mice. Likewise, in vitro invasiveness was reduced approximately 50%. The in vivo invasion assay using tracheal xenotransplants showed even more drastic reductions of the invasive ability of PDX-transfected cells (up to an 80% decrease). PDX-transfected cells did not invade or penetrated less into the tracheal wall tissues than their vector alone-transfected counterparts. In addition, the former cells showed a remarkable decrease in MMP-2 processing and activity. After PDX transfection the cells were less efficient in processing the tumor progression-associated furin substrates transforming growth factor beta1 and pro-membrane type 1-MMP. These findings indicate that furin inhibition is a feasible approach to attenuate and even abolish certain critical attributes of the advanced malignant phenotype. Thus, furin should be considered as a promising target for cancer therapy.

Animals↗

PubMed2001

Onset of natural killer cell lymphomas in transgenic mice carrying a truncated HMGI-C gene by the chronic stimulation of the IL-2 and IL-15 pathway.

Rearrangements of the high mobility group protein I-C (HMGI-C) gene, consisting in the loss of the carboxyl-terminal tail, have been frequently detected in benign human tumors of mesenchymal origin. We have previously demonstrated that transgenic (TG) mice carrying a truncated HMGI-C construct (HMGI-C/T) exhibit a giant phenotype together with a predominantly abdominal/pelvic lipomatosis. Here, we report that HMGI-C/T TG mice develop natural killer (NK)-T/NK cell lymphomas starting from 12 months of age. We found an increased expression of IL-2 and IL-15 proteins and their receptors in these lymphomas, and we demonstrate that HMGI-C/T protein positively regulates their expression in vitro. Therefore, the HMGI-C/T-mediated chronic stimulation of the IL-2/IL-15 pathway could be responsible for the onset of NK-T/NK cell lymphomas in HMGI-C/T TG mice.

Animals↗

PubMed2001

Exisulind, a novel proapoptotic drug, inhibits rat urinary bladder tumorigenesis.

Exisulind (Aptosyn) is a novel antineoplastic drug being developed for the prevention and treatment of precancerous and malignant diseases. In colon tumor cells, the drug induces apoptosis by a mechanism involving cyclic GMP (cGMP) phosphodiesterase inhibition, sustained elevation of cGMP, and protein kinase G activation. We studied the effect of exisulind on bladder tumorigenesis induced in rats by the carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine. Exisulind at doses of 800, 1000, and 1200 mg/kg (diet) inhibited tumor multiplicity by 36, 47, and 64% and tumor incidence by 31, 38, and 61%, respectively. Experiments on the human bladder tumor cell line, HT1376, showed that exisulind inhibited growth with a GI(50) of 118 microM, suggesting that the antineoplastic activity of the drug in vivo involved a direct effect on neoplastic urothelium. Exisulind also induced apoptosis as determined by DNA fragmentation, caspase activation, and morphology. Analysis of phosphodiesterase (PDE) isozymes in HT1376 cells showed PDE5 and PDE4 isozymes that were inhibited by exisulind with IC(50)s of 112 and 116 microM, respectively. Inhibition of PDE5 appears to be pharmacologically relevant, because treatment of HT1376 cells increased cGMP and activated protein kinase G at doses that induce apoptosis, whereas cyclic AMP levels were not changed. Immunocytochemistry showed that PDE5 was localized in discrete perinuclear foci in HT1376 cells. Immunohistochemistry showed that PDE5 was overexpressed in human squamous and transitional cell carcinomas compared with normal urothelium. The data lead us to conclude that future clinical trials of exisulind for human bladder cancer treatment and/or prevention should be considered and suggest a mechanism of action involving cGMP-mediated apoptosis induction.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2001

Role of 'platelet-type' 12-lipoxygenase in skin carcinogenesis.

Murine and human skin express an abundance of lipoxygenase isoforms whose functions are not understood. Substantial data have implicated a role for the 'platelet-type' 12-lipoxygenase (P-12LO) metabolite, 12(S)-hydroxy-eicosatetraenoic acid (12-HETE), in a variety of tumor functions. Using P-12LO deficient mice, we sought to examine the role of the P-12LO pathway in tumor initiation and progression. Two distinct genetic strains of P-12LO deficient and wild-type mice, B6/129 Sv and SENCAR, were evaluated in two-stage carcinogenesis experiments. Carcinoma incidence was significantly reduced in the P-12LO deficient mice of the B6/129 Sv background but not the SENCAR-backcrossed mice. In contrast, papilloma incidence was reduced on the SENCAR background but not in the B6/129 Sv strain mice. A separate experiment employing a complete carcinogenesis protocol failed to find any difference in papilloma or carcinoma incidence. Overall, these data suggest that the P-12LO pathway may contribute to tumor incidence and progression in two-stage, but not complete, carcinogenesis, depending on the genetic background.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2001

Elevated furin expression in aggressive human head and neck tumors and tumor cell lines.

Pro-protein convertases (PCs) are proteases that recognize and cleave precursor proteins. Furin, a well-studied PC, is ubiquitously expressed, and it has been implicated in many physiological and pathological processes. Some substrates for furin, such as membrane type 1 (MT1) matrix metalloproteinase (MMP), an MMP that activates gelatinase, a collagen-degrading enzyme, are associated with the advanced malignant phenotype. This report examines the expression of furin in carcinoma cell lines of different invasive ability. The levels of furin mRNA and protein correlated with the aggressiveness of tumor cell lines derived from head and neck and lung cancers. Furin expression also was investigated in primary head and neck squamous cell carcinomas (HNSCCs). Furin mRNA was not detected in nonmetastasizing carcinomas. In contrast, furin mRNA was expressed in metastasizing HNSCCs. Immunohistochemistry and Western blot analysis confirmed these results at the protein level. Furin activity was investigated indirectly by evaluating the expression of the pro-form and the processed form of MT1-MMP. Metastasizing HNSCCs showed increased expression of MT1-MMP. Furthermore, pro-MT1-MMP expression was noted in most of the nonmetastasizing HNSCCs analyzed by Western blot, and it was absent in the metastasizing HNSCCs. This finding suggests a lower level of furin-mediated MT1-MMP activation in the less aggressive cancers. These observations indicate that furin plays a role in tumor progression. Its overexpression in more aggressive or metastasizing cancers resulted in increased MMP processing.

Adult↗

PubMed2001

Image cytometry of cyclin D1: a prognostic marker for head and neck squamous cell carcinomas.

CCND1 gene amplification and cyclin D1 protein overexpression are indicators for poor prognosis in invasive head and neck carcinomas. Increased CCND1 gene dosage is a more sensitive prognostic factor than protein overexpression as evaluated by conventional immunohistochemical techniques. Qualitative immunohistochemistry cannot distinguish cyclin D1 overexpression accompanied by amplification of the CCND1 gene from overexpression associated with normal CCND1 gene copy number. To improve the sensitivity of cyclin D1 protein determination, we applied quantitative techniques of image analysis to evaluate cyclin D1 in 54 head and neck carcinomas. There was a significantly higher rate of occurrence of adverse events (P = 0.043) among patients with CCND1 gene amplification than among those without gene amplification. There was a strong association between CCND1 gene amplification (as detected by Southern blot analysis) and the highest nuclear score (by image cytometry of the immunostained tumor sections). The predominance of cells in the lowest nuclear score category was significantly associated with normal copy number (P = 0.005). Conversely, the highest nuclear score was a significant predictor of gene dosage (P = 0.02). Similarly, high nuclear score was a good predictor of death as the final outcome of the disease (P = 0.01). Although somewhat less accurate than Southern blotting, image cytometry of immunohistochemical cyclin D1 stain appears to be a promising tool that could be useful for other tumor marker expression studies.

Adult↗

PubMed2000

Analysis of the MRP4 drug resistance profile in transfected NIH3T3 cells.

BACKGROUND: Multidrug resistance-associated protein (MRP) 1 and canalicular multispecific organic anion transporter (cMOAT or MRP2) are adenosine triphosphate-binding cassette transporters that confer resistance to anticancer agents. In addition to these two transporters, there are at least four other human MRP subfamily members (MRP3 through MRP6). We and others reported previously that MRP3 is capable of conferring resistance to certain anticancer agents. In this study, we investigated whether MRP4 (MOAT-B), whose transcript accumulates to the highest levels in prostate tissue, has the capacity to confer drug resistance. METHODS: MRP4-transfected NIH3T3 cells were generated, and their drug sensitivity was analyzed. The subcellular localization of MRP4 was assessed by immunohistochemical analysis in transfected cells and in prostate tissue. Statistical tests were two-sided. RESULTS: MRP4 was detected as a 170-kd protein that was localized in the plasma membrane and cytoplasm of transfected cells. The MRP4 transfectants displayed 5.5-fold increased resistance to methotrexate in short-term drug-exposure assays (P=.022) and exhibited decreased cellular accumulation of this agent at 4 hours (P=.006) and 24 hours (P<.001). In continuous-exposure assays, however, the MRP4 transfectants did not display increased resistance for either methotrexate or natural product cytotoxic agents (anthracyclines, etoposide, vinca alkaloids, and paclitaxel [Taxol]). However, the transfectants did show increased resistance (2.3-fold) for the anti-acquired immunodeficiency syndrome nucleoside analogue 9-(2-phosphonylmethoxyethyl)adenine (PMEA) (P=.022) in continuous-exposure assays. Consistent with MRP4's plasma membrane localization in transfected cells, analysis of prostate tissue showed that MRP4 protein was localized primarily in the basolateral plasma membranes of tubuloacinar cells. CONCLUSIONS: These results indicate that MRP4 confers resistance to short-term methotrexate and continuous PMEA treatment. Given its structure, drug resistance profile and subcellular localization, MRP4 probably functions as an amphipathic anion efflux pump whose substrate range includes glutamate and phosphate conjugates.

3T3 Cells↗

PubMed2000

E2F-1 gene transfer enhances invasiveness of human head and neck carcinoma cell lines.

The transcription factor E2F-1, a downstream regulator of the p16-cyclinD-Rb pathway, is required for cell cycle progression. Evidence shows that overexpression of E2F-1 can either promote or inhibit development of tumors, depending on tissue or experimental conditions. To study whether the E2F-1 gene plays a role in tumor progression, the expression of E2F-1 protein was evaluated in 10 human head and neck squamous cell carcinoma cell lines using Western blot analysis. In addition, the invasive ability of these cell lines was determined by evaluating the penetration of cell lines into the tracheal wall in an in vivo invasion assay using deepithelialized tracheas transplanted into the s.c. tissue of Scid mice. This study showed that the aggressive cell lines had higher expression of E2F-1 than the less invasive cell lines. To evaluate the hypothesis that E2F-1 enhances invasiveness, we selected two cell lines, SCC9 and SCC12, for a gene transfer experiment. These cell lines exhibited low invasive ability with low expression of E2F-1. Two stable clones with overexpression of transfected E2F-1 gene and two clones with their respective vector-alone control were selected from each cell line for in vivo invasion evaluation. The clones containing the transfected E2F-1 gene had significantly higher invasive ability than their respective vector-alone clones. Flow cytometry showed that parental, transfected E2F-1, and vector-alone cells had a similar proliferation pattern under normal culture conditions. Nevertheless, transfected E2F-1 cells exhibited a higher portion of cells in S phase than the control cells after serum-starvation and refeeding. The results indicated that overexpression of E2F-1 plays a positive role in cell cycle reentry from quiescence and is associated with increased in vivo invasiveness.

Animals↗

PubMed2000

Role of NAD(P)H:quinone oxidoreductase 1 (DT diaphorase) in protection against quinone toxicity.

NQO1-/- mice, along with Chinese hamster ovary (CHO) cells, were used to determine the in vivo role of NAD(P)H:quinone oxidoreductase 1 (NQO1) in cellular protection against quinone cytotoxicity, membrane damage, DNA damage, and carcinogenicity. CHO cells permanently expressing various levels of cDNA-derived P450 reductase and NQO1 were produced. Treatment of CHO cells overexpressing P450 reductase with menadione, benzo[a]pyrene-3,6-quinone (BPQ), and benzoquinone led to increased cytotoxicity as compared with CHO cells expressing endogenous P450 reductase. In a similar experiment, overexpression of NQO1 significantly protected CHO cells against the cytotoxicity of these quinones. Knockout (NQO1-/-) mice deficient in NQO1 protein and activity had been generated previously in our laboratory and were used in the present studies. Wild-type (NQO1+/+) and knockout (NQO1-/-) mice were given i.p. injections of menadione and BPQ, followed by analysis of membrane damage and DNA damage. Both menadione and BPQ induced lipid peroxidation in hepatic and non-hepatic tissues, indicating increased membrane damage. Exposure to BPQ also resulted in increased hepatic DNA adducts in NQO1-/- mice as compared with NQO1+/+ mice. The skin application of BPQ alone and BPQ + 12-O-tetradecanoylphorbol-13-acetate (TPA) failed to induce papillomas, or other lesions, for up to 50 weeks in either NQO1+/+ or NQO1-/- mice. The various results from CHO cells and NQO1-/- mice indicated that NQO1 protects against quinone-induced cytotoxicity, as well as DNA and membrane damage. The absence of BPQ-induced skin carcinogenicity in NQO1-/- mice may be related to the strain (C57BL/6) of mice used in the present study and/or due to poor BPQ absorption into the skin and/or due to detoxification of BPQ by cytosolic NRH:quinone oxidoreductase 2 (NQO2).

Animals↗

PubMed2000

Synucleins are expressed in the majority of breast and ovarian carcinomas and in preneoplastic lesions of the ovary.

BACKGROUND: The synucleins (alpha, beta, and gamma) are a family of small cytoplasmic proteins that are expressed predominantly in neurons. alpha synuclein has attracted considerable attention due to its involvement in neurodegenerative diseases. Abnormal expression of gamma synuclein has recently been reported in some breast tumors. In this study, the authors examined a panel of breast and ovarian carcinomas for expression of alpha, beta, and gamma synucleins. METHODS: Normal breast and ovary tissue samples, tissue from ovaries of women at high risk of ovarian carcinoma, and tissue from breast and ovarian carcinomas were screened by immunohistochemistry and Western blot analysis for synuclein expression. RESULTS: Synucleins were not detectable by Western blot analysis in normal breast tissue. Eighty-two percent (14 of 17) of Stage III/IV breast ductal carcinomas expressed beta synuclein, gamma synuclein, or both simultaneously. Expression of alpha synuclein was not detected in breast carcinomas by Western blot analysis. Synuclein (alpha, beta, and gamma) expression was not detectable by immunohistochemistry in normal ovarian epithelium. Eighty-seven percent (39 of 45) of ovarian carcinomas were found to express at least 1 type of synuclein, and 42% (19 of 45) expressed all 3 synucleins (alpha, beta, and gamma) simultaneously. Highly punctate gamma synuclein expression was also observed in 20% of preneoplastic lesions of the ovary, including epithelial inclusion cysts, hyperplastic epithelium, and papillary structures, suggesting that gamma synuclein up-regulation may occur early in the development of some ovarian tumors. CONCLUSIONS: alpha, beta, and gamma synuclein are expressed in a high percentage of ovarian and breast carcinomas, and abnormal gamma synuclein expression may occur early in the development of ovarian carcinoma.

Adenocarcinoma↗

PubMed2000

Markers of proliferation in normal and leukoplakic oral epithelia.

We have reviewed the recent literature on immunohistochemical markers of cell proliferation in normal oral epithelia and leukoplakias. Most findings, including our own, point to an increased proliferation in oral leukoplakias that correlates with the degree of dysplasia. Although the basal layer of normal oral epithelia showed a very low proliferative activity, oral leukoplakias, even those containing low-grade dysplasia, exhibited a very significant increase in proliferation. High-grade dysplasia could be clearly differentiated from both low-grade dysplasia and normal oral epithelia by the presence of proliferating cells in the superficial cell strata, i.e. above or superficial to the parabasal layer. These changes were detected with several markers including PCNA, Ki-67 (Mib-1), cyclin D1 and CENP-F as well as with procedures using pulse labeling with BrDU, IrDU and tritiated thymidine. Comparison of all methods showed more similarities than discrepancies. Nevertheless, because of its relative simplicity of use and universal acceptance in many other sites, Ki-67 (Mib-1) seems to be the most reliable immunohistochemical marker for future use in cancer prevention and therapeutic clinical trials.

Biomarkers↗

PubMed2000

E2F-1: a proliferative marker of breast neoplasia.

E2F-1 is the best known ultimate transcription factor in the cyclin/cyclin-dependent kinase/retinoblastoma gene pathway and is probably involved in carcinogenesis and tumor progression. Because E2F-1 can be detected in paraffin sections using immunohistochemical techniques, it could be a useful tumor/proliferation marker. We studied the expression of this gene product in 130 breast tissue specimens from 100 patients and compared it with the expression of Mib-1, the widely used prognostic/proliferative marker, to assess E2F-1 as a new marker of neoplastic proliferation. The percentage of E2F-1-positive cells increased from 1.9% in the normal breast (NB) to 6.3% in ductal carcinoma in situ (DCIS) and to 15.3% in invasive ductal carcinomas (IDC). In addition, higher-grade tumors as well as advanced-stage disease correlated with higher expression of E2F-1. A similar tendency of Mib-1 expression was observed. There was a positive correlation between the E2F-1 and Mib-1 indices. In an in vitro experiment, we found that a similar difference in the expression of E2F-1 existed between a nontumorigenic breast cell line and two widely used breast carcinoma cell lines. The breast carcinoma cell lines T-47D and MCF-7 had more E2F-1-positive cells than the nontumorigenic cell line MCF-10F by immunohistochemistry and Western blot analysis. Because E2F-1 expression was significantly higher in IDC and DCIS than in NB, this study indicates that deregulation of E2F-1 may be involved in the development of breast IDC. In addition, E2F-1 expression could also be involved in tumor progression because the increased E2F-1 index correlated with the known prognostic predictors of breast cancer, such as histological grade, stage, metastasis status, estrogen receptor/progesterone receptor and Mib-1 expression. Thus, E2F-1 is a promising candidate to become a new prognostic/predictive marker of breast cancer.

Adult↗

PubMed2000

The proprotein convertases furin and PACE4 play a significant role in tumor progression.

Processing of latent precursor proteins by proprotein convertases (PCs) into their biologically active products is a common mechanism required for many important biologic functions. This process is tightly regulated, leading to the generation of active peptides and proteins including neuropeptides and polypeptide hormones, protein tyrosine phosphatases, growth factors and their receptors, and enzymes including matrix metalloproteases (MMPs). These processing reactions occurs at pairs of basic amino acids. Within the past several years, a novel family of Ca(2+)-dependent serine proteases has been identified, all of which possess homology to the endoproteases subtilisin (bacteria) and kexin (yeast). This family of PCs is currently comprised of fewer than a dozen members, known as furin/paired basic amino-acid-cleaving enzyme (PACE), PC1/PC3, PC2, PC4, PACE4, PC5/PC6, and PC7/PC8/lymphoma proprotein convertase. They share a high degree of amino-acid identity of 50-75% within their catalytic domains. Despite the relatively high degree of homology in the PC family, only PACE4 and furin localize to the same chromosome: mouse chromosome 7 and human chromosome 15. Recent reports have supported a possible functional role for PCs in tumorigenesis. For instance, convertases have been shown to be expressed in various tumor lines and human primary tumors. Furin and PACE4 process stromelysin 3 (MMP-11 or Str-3), an MMP involved in tumor invasion, into its mature, active form. Similarly, a growing family of MMPs, known as membrane-type metalloproteinases (MT-MMPs), and growth factors and adhesion molecules such as E-cadherin show similar amino-acid motifs and thus could be activated by furin and PACE4. These data, taken together with the high expression levels of PACE4 in 50% of murine chemically induced spindle cell tumors, confer to PACE4 and possibly other PCs a possible functional role in the activation of MMPs and consequently in tumor cell invasion and tumor progression. This was further supported by the remarkable enhancement in the invasive ability of the PACE4-transfected murine tumor cell lines. Mol. Carcinog. 28:63-69, 2000.

Animals↗

PubMed1999

The expression of a truncated HMGI-C gene induces gigantism associated with lipomatosis.

Rearrangements of the HMGI-C gene have frequently been detected in human benign tumors of mesenchymal origin, including lipomas. The HMGI-C protein has three AT-hook domains and an acidic COOH-terminal tail. The HMGI-C modifications consist in the loss of the C-tail and the fusion with ectopic sequences. Recent results show that the loss of the COOH-terminal region, rather than the acquisition of new sequences, is sufficient to confer to HMGI-C the ability to transform NIH3T3 cells. Therefore, transgenic mice carrying a HMGI-C construct (HMGI-C/T), containing only the three AT-hook domains, were generated. The HMGI-C/T mice showed a giant phenotype, together with a predominantly abdominal/pelvic lipomatosis, suggesting a pivotal role of the HMGI-C truncation in the generation of human lipomas.

3T3 Cells↗

PubMed1999

Antisense cyclin D1 induces apoptosis and tumor shrinkage in human squamous carcinomas.

Cyclin D1 plays an essential regulatory role in the G1 phase of the cell cycle. The cyclin D1 gene is amplified in 20-50% of squamous cell carcinomas (SCCs), and the protein is overexpressed in up to 80% of SCCs. Our hypothesis was that gene transduction of antisense (AS) cyclin D1 in human SCCs in vivo would result in tumor reduction. A cyclin D1 cDNA was inserted into an E1/E3-deficient serotype 5 adenovirus (AS cyclin D1) in an AS orientation using homologous recombination. AS cyclin D1 transduction suppressed cyclin D1 protein expression in both cultured cells and tumors. AS cyclin D1 significantly inhibited cell proliferation by both [3H]thymidine incorporation in six SCC cell lines (P = 0.01-0.001) and the conversion of tetrazolium salt to formazan in four SCC cell lines (P = 0.01-0.004). Apoptosis detected in >25% of cells in each cell line 48 h after AS cyclin D1 transduction paralleled the reduction in cyclin D1 protein. Preformed SCCs transduced with AS cyclin D1 were significantly inhibited (P = 0.002-0.005), and apoptosis was prominent in the AS cyclin D1-treated tumors, but not in tumors treated with the control vector. These data extend prior in vitro and ex vivo results and indicate that AS cyclin D1 suppresses SCC growth both in vitro and in vivo through suppression of cyclin D1 protein expression, leading to cellular apoptosis. Our findings suggest that cyclin D1 may have a role in cell survival and that cyclin D1 AS therapy may be useful as an adjunct to standard treatment for SCC.

Adenoviruses, Human↗

PubMed1999

The novel Trk receptor tyrosine kinase inhibitor CEP-701 (KT-5555) exhibits antitumor efficacy against human pancreatic carcinoma (Panc1) xenograft growth and in vivo invasiveness.

The survival rate for patients with pancreatic ductal adenocarcinoma (PDAC) is among the poorest for all cancers. The factors that contribute to this poor prognosis are lack of effective early detection, high rate of metastases and a generally refractory response to available treatment modalities. The most commonly used treatment methods--chemotherapy and radiation therapy--are mainly used for symptom palliation, with surgery being the only "curative" treatment option. The use of combinations of treatment modalities is the only therapy available to patients with locally advanced disease or that which is surgically unresectable. These options are still not sufficient to increase patient survival time significantly. The aggressive behavior and poor prognosis of this cancer is associated with an increased expression of many growth factors and their cognate receptors. We have demonstrated previously the aberrant expression of the Trk receptors (Trks A, B, and C) in PDAC specimens and human PDAC-derived cell lines and a biphasic, dose-dependent response of specific neurotrophic agents on the in vitro invasiveness of PDAC cells. Based on these data we have evaluated the therapeutic potential of inhibiting neurotrophin-Trk interactions using a selective Trk tyrosine kinase inhibitor (CEP-701) on subcutaneous (s.c.) and tracheal xenografts derived from the poorly differentiated PDAC cell line, Panc1. We demonstrate that CEP-701 administration at 10 mg/kg s.c. BID for 21 days inhibited tumor growth of the Panc1 s.c. xenografts in a statistically-significant manner (p < 0.01) compared to vehicle controls, in the absence of morbidity and mortality. A T/C value of 25% was observed for CEP-701-treated s.c. xenografts. In addition, CEP-701 administration inhibited tumor cell invasion in the s.c. tracheal xenograft model of in vivo invasiveness. Taken together, these data suggest that further studies are warranted to evaluate CEP-701 as a potential therapeutic agent in the treatment of PDAC.

Adenocarcinoma↗

PubMed1999

Neurotrophins and Trk receptors in human pancreatic ductal adenocarcinoma: expression patterns and effects on in vitro invasive behavior.

The aggressive and highly metastatic behavior observed in pancreatic ductal adenocarcinoma (PDAC) may be due to autocrine and/or paracrine interactions (tumor/stromal) involving altered expression of peptide growth factors and their corresponding receptors. The neurotrophin (NT) growth factor family and their cognate receptors have been demonstrated to play a role in the invasiveness, chemotactic behavior and tumor cell survival of both neuronal and non-neuronal cancers. We hypothesized that aberrant expression of the NTs and/or the Trk receptors may contribute to the malignant phenotype of PDAC, specifically tumor cell invasiveness, through autocrine and/or paracrine interactions. In this study, we examined the expression of NTs, Trks and p75NGFR by immunohistochemical and in situ hybridization analyses in both normal (n=14) and neoplastic pancreas (n=47) and PDAC-derived cell lines (n=6). Further, we evaluated the effects of various NTs on the in vitro invasive and chemotactic behavior on 6 human PDAC-derived cell lines in a modified Boyden chamber assay. Brain-derived nerve growth factor (BDNF), NT-3, NT-4/5 and Trks A, B and C exhibited diffuse cytoplasmic and membranous immunostaining patterns in both the ducts and the acini of the exocrine pancreas and the islets of the endocrine pancreas of both normal and PDAC specimens. NT expression was primarily within the stromal compartment of the tumor, while Trk expression was weak or absent. We observed a 68%, 64% and 66% increase in the expression of Trks A, B and C, respectively, in the ductal elements of the PDAC samples examined compared with the normal adjacent tissue. Invasiveness of 4 of 6 PDAC cell lines was significantly inhibited (p<0.05) when the cells were incubated with 100 ng/ml NT. However, when select cell lines were incubated with lower concentrations of NT-3 and BDNF (0, 1, 5, 25 and 50 ng/ml), invasiveness was significantly stimulated (p<0.05) through the Matrigel matrix. Collectively, our data suggest the possibility that paracrine and/or autocrine NT-Trk interactions may influence the phenotype (possibly the invasive behavior) of PDAC.

3T3 Cells↗