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Murray Korc

Publications and source records attributed to Murray Korc.

At least 37 records · Page 2Linked to original sources
PubMed2004

Thioredoxin is downstream of Smad7 in a pathway that promotes growth and suppresses cisplatin-induced apoptosis in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive human malignancy in which Smad7 is commonly overexpressed. Analysis by differential display identified thioredoxin-1 (TRX) as a gene whose basal expression is increased in COLO-357 pancreatic cancer cells engineered to overexpress Smad7. To delineate the biological consequences of TRX overexpression, we assessed TRX mRNA levels in PDAC and studied the effects of increased TRX levels in Smad7-overexpressing cells. By northern blotting, TRX mRNA levels were increased in PDAC samples by comparison with the normal pancreas. Moreover, analysis of laser-captured pancreatic cancer cells revealed parallel increases in Smad7 and TRX mRNA levels. Retroviral infection of an antisense TRX cDNA suppressed TRX protein levels and blunted the increased capacity of Smad7-overexpressing cells to form colonies in soft agar. 1-Methyl-propyl-2-imidazolozyl disulfide, a TRX inhibitor, markedly suppressed the growth of sham-transfected COLO-357 cells and enhanced the growth inhibitory actions of cis-diamminedichloroplatinum(II) (CDDP). CDDP also induced apoptosis, as evidenced by induction of DNA laddering, PARP cleavage, and caspase-3/9 activities. These pro-apoptotic actions were greatly attenuated in Smad7-overexpressing cells, which exhibited a more prolonged association of TRX with the apoptosis inducer apoptosis signal-regulating kinase-1, and enhanced nuclear factor kappaB activation in response to CDDP. These findings suggest that TRX is downstream of Smad7 in a pathway that confers a growth advantage to pancreatic cancer cells and that increases their resistance to CDDP-mediated apoptosis, implying novel regulatory functions for Smad7.

Antineoplastic Agents↗
PubMed2004

Vascular endothelial growth factor-trap suppresses tumorigenicity of multiple pancreatic cancer cell lines.

PURPOSE: Vascular endothelial growth factor A (VEGF-A) is a potent angiogenic agent that binds to two high affinity VEGF receptors (VEGFRs), a process facilitated by the low affinity neuropilin receptors. Although VEGF-A is overexpressed in pancreatic ductal adenocarcinoma, it is not known whether the in vivo growth of multiple pancreatic cancer cells can be efficiently blocked by VEGF-A sequestration. EXPERIMENTAL DESIGN: Four human pancreatic cancer cell lines were grown s.c. in athymic nude mice. One cell line also was used to generate an orthotopic model of metastatic pancreatic cancer. The consequences of VEGF-A sequestration on tumor growth and metastasis were examined by injecting the mice with a soluble VEGFR chimer (VEGF-Trap) that binds VEGF-A with high affinity. RESULTS: VEGF-Trap, initiated 2 days after tumor cell inoculation, suppressed the s.c. growth of four pancreatic cancer cell lines and markedly decreased tumor microvessel density. Analysis of RNA from tumors generated with T3M4 cells revealed that VEGF-Trap decreased the expression of VEGFR-1 and neuropilin-1 and -2. VEGF-Trap, initiated 3 weeks after tumor implantation, also attenuated intrapancreatic tumor growth and metastasis in an orthotopic model using PANC-1 cells. CONCLUSIONS: VEGF-Trap is a potent suppressor of pancreatic tumor growth and metastasis and also may act to attenuate neuropilin-1 and -2 and VEGFR-1 expression. Therefore, VEGF-Trap may represent an exceedingly useful therapeutic modality for pancreatic ductal adenocarcinoma.

Animals↗
PubMed2004

Enhanced expression of 14-3-3sigma in pancreatic cancer and its role in cell cycle regulation and apoptosis.

14-3-3sigma belongs to the 14-3-3 family of proteins, which are involved in the modulation of diverse signal transduction pathways. Loss of 14-3-3sigma expression has been observed in a number of human cancers, suggesting that it may have a role as a tumor suppressor gene. The aim of the study was to investigate the expression and the functional role of 14-3-3sigma in pancreatic ductal adenocarcinoma (PDAC). Expression of 14-3-3sigma was analyzed using laser capture microdissection (LCM), quantitative real-time-PCR (QRT-PCR), DNA arrays, immunohistochemistry and western blot analysis. The role of 14-3-3sigma in apoptosis and cell cycle regulation was evaluated by western blotting, immunoprecipitation and FACS analysis. By QRT-PCR, 14-3-3sigma mRNA levels were 54-fold increased in pancreatic adenocarcinoma in comparison with normal pancreatic samples and localized in pancreatic cancer cells as determined by LCM. In pancreatic cancer cells, the degree of 14-3-3sigma expression was not decisive for the maintenance of G(2)/M cell cycle checkpoint or induction of apoptosis. Responses to radiation or apoptosis-inducing agents were neither accompanied by a significant 14-3-3sigma accumulation nor by a change in association of 14-3-3sigma with cdc2, bad and bax. In conclusion, the marked over-expression of 14-3-3sigma in PADC together with multiple known genetic and epigenetic alterations of potential 14-3-3sigma interacting partners suggests an important role of aberrant 14-3-3sigma downstream signaling in pancreatic cancer.

14-3-3 Proteins↗
PubMed2004

Aberrant expression of neuropilin-1 and -2 in human pancreatic cancer cells.

PURPOSE: Neuropilin (Np)-1 and -2 are coreceptors for vascular endothelial growth factor (VEGF). This study was designed to assess their role in pancreatic ductal adenocarcinoma (PDAC). EXPERIMENTAL DESIGN: We assessed Np-1 and Np-2 expression by real-time quantitative PCR in relation to the expression of VEGF ligands and receptors in pancreatic cancer cell lines and tissues. RESULTS: ASPC-1, CAPAN-1, and PANC-1 pancreatic cancer cells and tumor-derived, laser-captured pancreatic cancer cells exhibited higher Np-1 and Np-2 mRNA levels than VEGF receptor-1, -2, or -3 mRNA levels. Transfection of Np-1 and Np-2 cDNAs in COS-7 cells, and treatment with tunicamycin revealed that both proteins were glycosylated. Both proteins were expressed in pancreatic cancer cell lines, in the PDAC samples, and in acinar cells adjacent to the cancer cells. The normal pancreas was devoid of Np-1 immunoreactivity, whereas Np-2 immunoreactivity was present in the endocrine islets and in some acinar cells, but not in ductal cells. CONCLUSIONS: The aberrant localization of Np-1 and Np-2 in the cancer cells in PDAC suggests that in addition to exerting proangiogenic effects, these coreceptors may contribute to novel autocrine-paracrine interactions in this malignancy.

Animals↗
PubMed2004

Expression and functional significance of CDC25B in human pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related deaths. Deregulation of cell-cycle control is thought to be a crucial event in malignant transformation, and CDC25 phosphatases are a family of cyclin-dependent kinase activators, which act at different points of the cell cycle, including G1-S and G2-M transition. Here, we investigated the expression and functional significance of CDC25s in PDAC. CDC25B mRNA expression levels in human pancreatic tissue samples were analysed by cDNA array, quantitative PCR and Northern blotting. Immunohistochemistry was carried out to localize and quantify CDC25B expression. Two specific CDC25B inhibitors were utilized to determine the functional relevance of CDC25B. By quantitative RT-PCR, CDC25B mRNA was overexpressed in pancreatic cancer (7.5-fold) in comparison to the normal pancreas. Strong nuclear CDC25B immunoreactivity was present in both pancreatic and metastatic cancer samples, and there was a marked increase of the percentage of positive cells in primary cancer (48.6+/-16.3%) and metastatic tissues (71.7+/-3.1%) compared to normal samples (8.3+/-1.8%). Two CDC25B inhibitors reduced the growth of pancreatic cancer cell lines, resulting in the accumulation of phosphorylated CDC2 and G2/M arrest. These findings demonstrate an important role of CDC25B in cell-cycle progression, raising the possibility that inhibition of CDC25B may have therapeutic potential in pancreatic cancer.

Adenocarcinoma↗
PubMed2004

Adenovirus-mediated transfer of a truncated fibroblast growth factor (FGF) type I receptor blocks FGF-2 signaling in multiple pancreatic cancer cell lines.

Pancreatic ductal adenocarcinomas (PDACs) overexpress several members of the fibroblast growth factor (FGF) family of ligands and the type I FGF receptor (FGFR-1), and enhanced FGF-2 protein levels correlate with shorter postoperative survival of patients with PDAC. In this study, we investigated the effects of FGF-2 on cell proliferation and mitogen-activated protein kinase (MAPK) activation before and after abrogation of FGFR-1-dependent signaling in 4 pancreatic cancer cell lines (ASPC-1, COLO-357, MIA-PaCa-2, and PANC-1). Signaling was blocked by infecting the cells with an adenoviral vector encoding for a truncated FGFR-1 (AdtrFGFR-1). FGF-2 enhanced the growth of all 4 cell lines and activated MAPK in 3 of these cell lines. Infection with the AdtrFGFR-1 virus resulted in abundant expression of the truncated FGFR-1 at the RNA and protein level, markedly attenuated FGF-2-induced proliferation in all 4 tested cell lines, and decreased FGF-2-dependent MAPK activation in the 3 cell lines in which FGF-2 activated this pathway. These findings suggest that FGFR-1-mediated mitogenesis in multiple pancreatic cancer cells can be efficiently blocked with an adenoviral vector encoding a truncated FGFR-1, raising the possibility that AdtrFGFR-1 may ultimately have a therapeutic role in PDAC.

Adenoviridae↗
PubMed2004

Update on diabetes mellitus.

Diabetes mellitus is a complex multi-system disorder that may be classified as autoimmune mediated type 1 diabetes, or as insulin resistance associated type 2 diabetes. In type 1 diabetes, there is selective loss of the beta cells within the endocrine islets, as a consequence of T-cell and cytokine mediated destruction of these cells, perhaps in conjunction with destruction of the peri-islet Schwann cells. In type 2 diabetes, the etiology of the resistance ranges from post-receptor defects in the insulin signaling pathway to excessive production of adipocyte derived cytokines that antagonize insulin action to mitochondrial defects that interfere with glucose disposal. Proteome based technologies are providing new insights into these defects.

Autoimmunity↗
PubMed2004

Gefitinib ('Iressa', ZD1839), a selective epidermal growth factor receptor tyrosine kinase inhibitor, inhibits pancreatic cancer cell growth, invasion, and colony formation.

Pancreatic cancer is a devastating malignancy, characterized by low responsiveness to conventional chemotherapies. Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) has shown clinical activity against EGFR-expressing tumors. Since pancreatic cancers frequently overexpress EGFR (ErbB-1) and its ligands, our aim was to investigate the potential role of gefitinib in this disease. The GI50 of gefitinib as well as the effects of gefitinib on growth factor actions in pancreatic cancer cell lines were analyzed using MTT assays. FACS analysis using Annexin and propidium iodide (PI) staining were performed to study cell cycle, apoptosis and cell death. Western blot analysis was carried out to investigate expression levels of the 4 members of the ErbB family of receptors in pancreatic cancer cell lines, as well as MAP kinase and EGFR phosphorylation. Soft agar assays were used to measure colony formations. Invasiveness of cancer cells was analyzed using Matrigel-coated filters. gefitinib inhibited cell proliferation of pancreatic cancer cell lines with GI50 concentrations ranging from 2.5 to over 10 micro M. Gefitinib completely inhibited EGF-induced cell proliferation, but did not significantly influence insulin-like growth factor (IGF)-induced mitogenesis. Gefitinib also completely abolished EGF-induced phosphorylation of EGFR and MAP kinase. Furthermore, gefitinib inhibited basal and EGF-induced anchorage-independent cell growth and invasion. Our data demonstrate that gefitinib inhibits pancreatic cancer cell growth through EGFR-dependent pathways. Gefitinib also inhibits anchorage-independent growth and invasiveness, suggesting that gefitinib may offer a new approach for the treatment of pancreatic cancer.

Animals↗
PubMed2003

Reverse transcription-PCR analysis of laser-captured cells points to potential paracrine and autocrine actions of neurotrophins in pancreatic cancer.

PURPOSE: Neurotrophins (NTs) can stimulate cell proliferation and differentiation in various cell types, and play a role in certain human cancers. In this study we analyzed the expression and localization of NTs and their receptors in microdissected pancreatic cancer tissue samples, and studied their ability to stimulate cell growth. EXPERIMENTAL DESIGN: The expression of nerve growth factor, brain-derived neurotrophic factor, NT-3, and NT-4/5, and the receptors tropomyosin receptor kinase A, B, and C, and P75 was studied in pancreatic cancer cell lines, and normal and pancreatic ductal adenocarcinoma (PDAC) tissue samples by quantitative reverse transcription-PCR. Laser capture microdissection was performed in 21 PDAC samples, and mRNA levels were determined in cancer cells, acinar cells, desmoplastic stroma areas, and nerve fibers. Cell growth assays with NTs and in coculture with dorsal root ganglia were performed. RESULTS: NT receptors were differentially expressed in the cancer cell lines, whereas tropomyosin receptor kinase C was not detectable. NTs modulated pancreatic cancer cell growth. Analysis of nonmicrodissected samples revealed that all of the receptors and tested ligands were overexpressed in PDAC when compared with normal pancreas. Analysis of laser captured samples revealed that NTs and their receptors were expressed in the cancer cells but were especially abundant in the intratumoral nerves. Coculture of dorsal root ganglia with T3M4 cells significantly enhanced the proliferation of this cell line. CONCLUSION: The abundance of NTs in the intratumoral nerves in PDAC and the presence of NT receptors in the cancer cells, in conjunction with the ability of NTs to modulate pancreatic cancer cell growth, point to potential paracrine and autocrine effects of NTs in PDAC. Thus, our findings provide additional evidence that blocking NT actions may have a therapeutic potential in PDAC.

Adenocarcinoma↗
PubMed2003

Loss of beta-catenin expression in metastatic gastric cancer.

PURPOSE: Beta-catenin (beta-catenin) participates in intercellular adhesion and is an integral part of the Wnt signaling pathway. The role of beta-catenin in the pathogenesis of gastric cancer and its metastasis is largely unknown. PATIENTS AND METHODS: Immunohistochemistry and Western blot analysis were used to analyze the expression of beta-catenin in 87 human gastric cancers, in metastasis and cancer cell lines. The beta-catenin and the adenomatous polyposis coli (APC) genes were analyzed for gene mutations. Furthermore, methylation of the beta-catenin promoter in cell lines was assessed by treatment with 5'-azadeoxycytidine and sodium bisulfite genomic sequencing. RESULTS: beta-Catenin expression was present at either the cell membrane or the cytoplasm in 34 of 75 primary gastric cancers. Expression of beta-catenin was significantly more frequent in intestinal-type (P =.0049) and well-differentiated gastric cancers (P <.001). There were no quantitative differences between gastric cancers and the nonmalignant gastric tissues, as determined by Western blot analysis. One of 18 metastatic cancer lesions and four of five gastric cancer cell lines expressed beta-catenin protein. N87 cells, derived from the liver metastasis of a gastric cancer, did not express beta-catenin. Treatment with 5'-azadeoxycytidine restored beta-catenin protein levels in this cell line, which exhibited significantly more 5-methylcytosines in the beta-catenin promoter compared with the other cell lines. CONCLUSION: beta-Catenin expression is lost in a subgroup of primary gastric cancers, is frequently absent in metastases, and exhibits nuclear localization in cancers with either beta-catenin or APC gene mutations. Interestingly, the loss of beta-catenin expression in metastatic gastric cancers may result from hypermethylation of the beta-catenin promoter.

Adenomatous Polyposis Coli↗
PubMed2003

Down-regulation of the dual-specificity phosphatase MKP-1 suppresses tumorigenicity of pancreatic cancer cells.

BACKGROUND & AIMS: In both pancreatic cancer and chronic pancreatitis, there is enhanced expression of mitogenic growth factors and their tyrosine kinase receptors, which have the capacity to activate mitogen-activated protein kinase (MAPK). In view of the important role of MAPK kinase phosphatase (MKP)-1 in the regulation of MAPK activation, the expression and functional role of MKP-1 was analyzed. METHODS: Pancreatic tissues were analyzed by Northern blotting, Western blotting, and immunohistochemistry. Pancreatic cancer cells were transfected with a full-length MKP-1 antisense construct. Growth characteristics and tumorigenicity in vivo and the effects of mitogenic growth factors on cell growth and MAPK activation were determined in transfected and control cells. RESULTS: MKP-1 messenger RNA (mRNA) levels were increased in pancreatic cancer and chronic pancreatitis (CP) tissues. Moderate to strong MKP-1 immunoreactivity was present in the cancer cells, ductal cells of pancreatic intraepithelial neoplasia, and in tubular complexes in CP. Down-regulation of MKP-1 resulted in decreased anchorage-dependent and -independent growth of pancreatic cancer cells, and decreased tumorigenicity in a nude mouse tumor model. MKP-1 down-regulation led to decreased proliferation and sustained MAPK activation in response to mitogens. CONCLUSIONS: Suppression of MKP-1 expression reduces the tumorigenicity of pancreatic cancer cells in vivo, suggesting that MKP-1 contributes to enhanced mitogenic signaling in pancreatic cancer cells.

Adolescent↗
PubMed2003

Neurokinin-1 receptor expression and its potential effects on tumor growth in human pancreatic cancer.

The neurokinin-1 receptor (NK-1R) and its ligand substance P (SP) are involved in the pathogenesis of certain neural tumors. Because nerves are significantly altered in pancreatic cancer, evidence for alteration of this pathway in human pancreatic cancer was sought. Expression of NK-1R was analyzed by real-time quantitative RT-PCR, in situ hybridization, immunohistochemistry, and Western blot analysis in normal human pancreatic and pancreatic cancer tissue samples and in pancreatic cancer cell lines. Furthermore, the influence of SP analogs and of the NK-1R antagonist MEN 11467 on pancreatic cancer cell growth was analyzed by sulforhodamine B (SRB) assay. By real-time quantitative RT-PCR, NK-1R mRNA was increased 36.7-fold (p < 0.001) in human pancreatic cancer samples compared with normal controls. Enhanced NK-1R expression levels were not related to tumor grade but were associated with advanced tumor stage and poorer prognosis. By in situ hybridization and immunohistochemistry, NK-1R mRNA and immunoreactivity were only occasionally weakly present in acinar and ductal cells in the normal pancreas. In contrast, moderate to strong NK-1R mRNA signals and immunoreactivity were present in most cancer cells. By Western blot analysis, NK-1R was increased 26-fold (p < 0.01) in pancreatic cancer samples in comparison to normal controls. NK-1R mRNA was detected in five pancreatic cancer cell lines by real-time quantitative RT-PCR, with the highest levels in CAPAN-1 cells and the lowest in ASPC-1 cells. SP analogs stimulated pancreatic cancer cell growth, depending on the NK-1R expression level, and this effect could be blocked by a selective NK-1R antagonist. These findings illustrate that the NK-1R pathway is activated in human pancreatic cancer and has the potential to contribute to cancer cell growth, thus suggesting the existence of a neuro-cancer cell interaction in vivo.

Blotting, Western↗
PubMed2002

Induction and expression of betaig-h3 in pancreatic cancer cells.

betaig-h3 (TGFBI, keratoepithelin) was first identified as a transforming growth factor-beta1 (TGF-beta1)-inducible gene in a human lung adenocarcinoma cell line. It encodes for a secreted extracellular matrix (ECM) protein, which is thought to act on cell attachment and ECM composition. Mutations of the betaig-h3 gene are involved in several corneal dystrophies. Pancreatic cancers display multiple alterations in the TGF-beta signaling pathway and in TGF-beta response genes, such as overexpression of all three TGF-beta isoforms and Smad4 mutations. In this report, we determined that betaig-h3 mRNA levels were induced by TGF-beta1 in two out of five examined pancreatic cancer cell lines (CAPAN-1, PANC-1). In CAPAN-1 cells, which harbor a Smad4 mutation, betaig-h3 but not PAI-1 was induced by TGF-beta1, whereas in PANC-1 cells that express wild-type Smad4, TGF-beta1 induced both PAI-1 and betaig-h3. In human pancreatic tissues, there was a 32.4-fold increase in betaig-h3 mRNA levels in pancreatic cancers in comparison to normal control tissues. In situ hybridization analysis revealed that betaig-h3 mRNA was expressed mainly in the cancer cells within the pancreatic tumor mass. These findings suggest that betaig-h3 is induced by TGF-betas in pancreatic cancer cells even in the presence of Smad4 mutations, which might explain, in part, the increased betaig-h3 mRNA levels observed in pancreatic cancer cells in vivo.

Adolescent↗
PubMed2002

Multiple mitogenic pathways in pancreatic cancer cells are blocked by a truncated epidermal growth factor receptor.

The epidermal growth factor (EGF) receptor (EGFR) family consists of four transmembrane tyrosine kinases that undergo homodimerization and heterodimerization. Pancreatic cancers overexpress these receptors. To examine the effects of EGFR blockade on pancreatic cancer cell mitogenesis in relation to activation of specific signaling pathways, four pancreatic cancer cell lines were infected with an adenoviral vector encoding a truncated EGFR (AdtrEGFR), and activation of signaling was assessed with the mitogen-activated protein kinase (MAPK) kinase inhibitors PD98059 and U0126, the p38 MAPK inhibitor SB203580, and the c-Jun NH2-terminal kinase inhibitor SP600125. In all four cell lines, AdtrEGFR markedly attenuated EGF and heparin-binding EGF-dependent cell growth, EGFR family tyrosine phosphorylation, and phosphorylation of MAPK, c-Jun NH2-terminal kinase, p38 MAPK, and activating transcription factor 2. AdtrEGFR did not alter fibroblast growth factor 2 actions on mitogenesis. In ASPC-1, PANC-1, and T3M4 cells, PD98059 and U0126 inhibited MAPK kinase activation but not EGF-stimulated mitogenesis, whereas SB203580 inhibited EGF-stimulated mitogenesis, p38 MAPK activation, and MAPK-activated protein kinase 2 activation, without attenuating the mitogenic effect of insulin-like growth factor 1. In contrast, in COLO-357 cells, PD98059, and U0126, but not SB203580, inhibited EGF-stimulated mitogenesis, whereas SP600125 did not alter the mitogenic actions of EGF in any of the cell lines. Thus, EGF promotes proliferation via the MAPK in COLO-357 cells but via p38 MAPK in ASPC-1, PANC-1, and T3M4 cells, and whereas EGFR activation leads to the activation of all four members of the EGFR family in these cells, downstream signaling is efficiently blocked by AdtrEGFR.

Adenoviridae↗
PubMed2002

Adhesion molecules in human pancreatic cancer.

BACKGROUND AND OBJECTIVES: Adhesion molecules are cell surface glycoproteins that are important in cell-to-cell and cell-to-extracellular matrix interactions. In the present study, we analyzed the adhesion molecules ICAM-1 (intercellular adhesion molecule-1), VCAM-1 (vascular cell adhesion molecule-1), and ELAM-1 (endothelial leukocyte adhesion molecule-1) in human pancreatic cancer. METHODS: ICAM-1, VCAM-1, and ELAM-1 were analyzed in 20 pancreatic cancer specimens and 20 normal pancreatic tissues. mRNA expression encoding ICAM-, VCAM-1, and ELAM-1 was assessed with Northern blot analysis. The distribution and localization of ICAM-1, VCAM-1, and ELAM-1 was determined in the pancreatic specimens by immunohistochemistry. RESULTS: Northern blot analysis revealed a 5.4-fold increase of ICAM-1 (P<0.01) and a 3.7-fold increase in VCAM-1 (P<0.01) mRNA expression in cancer samples in comparison with normal controls. In contrast, ELAM-1 mRNA levels did not show significant differences between the cancer and the normal tissues. Immunohistochemical analysis of cancer tissues showed strong immunostaining for ICAM-1 and VCAM-1, and faint immunostaining for ELAM-1 in the pancreatic cancer cells. Fibrotic or noncancerous pancreatic tissue adjacent to the cancer mass was devoid of any immunoreactivity for ICAM-1, ELAM-1, and VCAM-1. In contrast, the normal pancreas exhibited no immunoreactivity of ICAM-1, ELAM-1, and VCAM-1. CONCLUSIONS: Enhanced expression of ICAM-1 and VCAM-1 in human pancreatic cancers suggests a role in tumor pathogenesis. The increase of these adhesion molecules might influence the detachment of cancer cells in the primary tumor, might contribute to cancer cell migration and the spread of cancer cells to distant organs, or both.

Adenocarcinoma↗
PubMed2002

Nerve growth factor and enhancement of proliferation, invasion, and tumorigenicity of pancreatic cancer cells.

Nerve growth factor (NGF) exerts both stimulatory and inhibitory effects on neuronal and certain non-neuronal tumors. In pancreatic cancer NGF is overexpressed, and this overexpression is associated with increased perineural invasion. NGF has the potential to stimulate the growth of some pancreatic cancer cell lines, and this effect is mediated by the phosphorylation of tyrosine kinase receptor A and mitogen-activated protein kinase activation; it is dependent on the expression levels of tyrosine kinase receptor A and p75 receptors. To determine whether cancer cell-derived NGF can participate in the regulation of pancreatic cancer cell proliferation, PANC-1 human pancreatic cancer cells were stably transfected with a full-length human beta-NGF expression vector. In vitro and in vivo growth characteristics were analyzed by proliferation assays and invasion assays and in a nude mouse tumor model. Stable transfection of NGF in PANC-1 cells resulted in enhanced anchorage-dependent growth, with a decrease in doubling times of up to 50%, and in an approximately twofold increase in anchorage-independent cell growth and cell invasion. Furthermore, stably transfected PANC-1 cells showed enhanced tumorigenicity in nude mice. These results suggest that NGF has the capacity to act in a paracrine and/or an autocrine manner in pancreatic cancer and that it enhances cancer cell growth and invasion in vivo, thereby contributing to the aggressiveness and poor prognosis of this disease.

Animals↗
PubMed2002

Glypican-3 expression is markedly decreased in human gastric cancer but not in esophageal cancer.

BACKGROUND: Deregulation of the expression of glypican-3, a heparan sulfate proteoglycan, has been demonstrated in several human cancers. METHODS: In the present study, glypican-3 mRNA expression was analyzed by Northern blotting and in situ hybridization in 20 normal and 41 cancerous esophageal specimens as well as in 15 normal and 32 cancerous gastric tissues. RESULTS: Glypican-3 mRNA was expressed in both normal and esophageal cancer tissues without a significant difference between normal and cancerous tissues, and without a correlation with histological type, tumor stage, tumor grade, or patient survival. Moderate to strong glypican-3 mRNA signals were found in the cytoplasm of squamous epithelial cells of the normal esophagus. In both squamous and adenocarcinomas of the esophagus glypican-3 mRNA signals were also moderately to strongly present in the cytoplasm of the cancer cells. In gastric tissues, glypican-3 mRNA was present in 53% of normal gastric tissue samples, but was below the detection level in all examined gastric cancer samples. Glypican-3 mRNA signals were moderately to strongly present in the cytoplasm of gastric mucosal epithelial cells, but were only very faintly present in some cancer cells. CONCLUSIONS: Glypican-3 may be involved in the growth control of normal esophageal and gastric epithelial cells. Furthermore, our results suggest that glypican-3 may play a tumor suppressor role in gastric but not in esophageal cancer.

Adult↗