Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pancreatic cancer is one of the most aggressive and devastating human malignancies. The present study was conducted to determine whether in vivo sst2 gene transfer into human pancreatic tumors would impair tumor progression, and to characterize sst2 antitumoral bystander mechanisms. sst2 administration, using the synthetic vector PEI, strongly inhibited tumor progression of human pancreatic adenocarcinoma, in vivo. sst2 gene transfer induced intratumoral production of its ligand somatostatin. Disruption of this autocrine loop by RNA interference completely reversed sst2 antitumoral activity. Mice depleted of natural killer (NK) cells did not hamper sst2 tumor growth inhibition. However, microvessel density and vascular endothelial growth factor (VEGF) expression were markedly reduced in sst2-transfected tumors, whereas sst3 somatostatin receptor was upregulated. Depleting somatostatin by RNA interference completely abolished the sst2 inhibitory effect on VEGF expression and tumor angiogenesis, and sst2-induced sst3 expression in peripheral tumor vessels. We conclude that in vivo sst2 gene transfer elicited intratumoral somatostatin production and strongly impaired human pancreatic tumor growth. NK cells were not involved in this antitumoral bystander effect. VEGF and tumor vascularization were identified as novel targets for sst2-mediated antitumoral bystander effect. sst3 somatostatin receptor was upregulated in sst2-transfected tumors. Therefore, in vivo gene delivery of sst2 receptor to target the angiogenic process in pancreatic ductal adenocarcinoma might be a new therapeutic approach for treatment of pancreatic cancer in patients with unresectable disease.
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PMID:Characterization of the bystander effect of somatostatin receptor sst2 after in vivo gene transfer into human pancreatic cancer cells. 1621 79

Camptothecin (CPT) was conjugated to the N-terminal of a somatostatin analog (SSA) directly via a carbamate group and a basic N-terminal linking motif, D-Lys-D-Tyr-Lys-D-Tyr-D-Lys. This new CPT-SSA conjugate termed JF-10-81 was evaluated as a receptor-specific delivery system for its anti-invasive and anti-angiogenic activities. It was found that, in addition to blocking migration and invasion of highly invasive prostate cancer PC-3 cells, this conjugate also inhibited in vitro capillary-like tube formation of endothelial cells and in vivo angiogenesis in C57B1/6N female mice. JF-10-81 was found to block PC-3 cell attachment to various extracellular matrix components, mainly to vitronectin, the ligand of cell surface receptors integrin alphaVbeta3 and alphaVbeta5. Additionally, JF-10-81 reduced expression of integrins alphaVbeta3 and alphaVbeta5 on PC-3 cell surfaces, without effects on beta1 or any alphabeta1 heterodimers. This conjugate also inactivated phosphorylation of protein kinase B (PKB/Akt), down-regulated the expression of latent matrix metalloproteinase (MMP) -2 and MMP-9, but had little effect on MMP-3/-10. Meanwhile, membrane type-1 matrix metalloproteinase (MT1-MMP) and the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) were not detectable in PC-3 cells. alphaVbeta3/alphaVbeta5 and MMP-2/-9 are known to be highly expressed in many tumor cells and play an important role in tumor progression. Our results support that this conjugate could possibly inhibit prostate cancer PC-3 cell invasion through a signaling pathway involving PI3K/Akt, alphaVbeta3/alphaVbeta5 and MMP-2/-9, and this SSA could be used as an efficient vector to deliver CPT or other cytotoxic agents to target sites for cancer therapy.
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PMID:A conjugate of camptothecin and a somatostatin analog against prostate cancer cell invasion via a possible signaling pathway involving PI3K/Akt, alphaVbeta3/alphaVbeta5 and MMP-2/-9. 1664 5

Pancreatic cancer is one of the most aggressive and devastating human malignancies. There is an urgent need for more effective therapy for patients with advanced disease. In this context, genetic therapy potentially represents a rational new approach to treating pancreatic cancer, which could provide an adjunct to conventional options. Because of the promise of recombinant SV40 vectors, we tested their ability to deliver a transgene, and to target a transcript, so as to inhibit pancreatic tumors growth in vivo. BxPC3 and Capan-1 cells were efficiently transduced using SV40 vectors without selection, as compared to synthetic vectors PEI. SV40 vectors were as efficient as adenoviral vectors, and provided long-term transgene expression. Next, we devised a SV40-derived, targeted gene therapy approach of pancreatic cancer, by combining hTR tumor-specific promoter with sst2 somatostatin receptor tumor-suppressor gene. In vitro cell proliferation was strongly impaired following administration of SV(hTR-sst2). SV40-derived sst2-mediated antiproliferative effect was dependent on the local production of somatostatin. In vivo, intratumoral gene transfer of sst2 using rSV40 vectors resulted in a marked inhibition of Capan-1 tumor progression, and proliferation. These results represent the initial steps toward a novel approach to the gene therapy of pancreatic cancer using SV40 as a vector.
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PMID:Replication-deficient rSV40 mediate pancreatic gene transfer and long-term inhibition of tumor growth. 1699 Aug 45

One hundred fifty-four consecutive patients with pheochromocytoma (PC, n=137) or paraganglioma (PG, n=17) were treated at our unit. Twenty patients had MEN 2, 15 VRD, and 1 VHL tumors. Twelve had malignant tumors and were classified according to mode of presentation: (1) Distant metastases (n=4); three underwent surgical debulking (with chemotherapy in one); and three had 131I-MIBG therapy. Within 4 years two patients died of tumor progression. (2) Locally advanced disease (n=4), all resected for cure. (3) Malignancy disclosed during follow-up after adrenalectomy with "benign" histopathology (n=4). All patients in groups 2 and 3 developed recurrence 9 (1-17) years after primary surgery; four underwent resection, one remains tumor-free. The others were treated chronically with phenoxybenzamine, combined with 131I-MIBG in one. These eight patients were observed 20 (5-35) years after primary surgery and 11 (1-19) years after recurrence. This series is population-based and may better reflect the natural history of malignant PC/PG than the series from national referral centers. Active surgical treatment and phenoxybenzamine resulted in low tumor-related mortality in groups 2 and 3; five patients died 8-30 years after diagnosis, four of PC/PG (three from group 2 and one from group 3) and one of other causes. We propose tumor uptake studies (MIBG- and octreotide scintigraphy) in patients with nonresectable metastases; to select individual radionuclide therapy data on the expression of CA-transporters/somatostatin receptors may be helpful. To diagnose PC/PG early, screening of adrenal incidentalomas has been suggested. In a regional population-based prospective study, 503 incidentalomas were reported during 18 months, but only one patient with PG was identified.
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PMID:Malignant pheochromocytoma in a population-based study: survival and clinical results. 1710 19

About 40% of nonfunctioning pancreatic endocrine carcinomas (NF-PEC) cannot be cured by surgery due to advanced stage disease. Somatostatin analogues have been proposed as first line therapy in these cases. We performed a prospective phase IV study to assess the efficacy of octreotide in advanced NF-PEC and identify factors predictive of response to therapy. Twenty-one consecutive patients with octreoscan-positive advanced-stage well-differentiated NF-PEC were treated with long-acting release octreotide 20 mg i.m. at diagnosis. The immunohistochemical expression of somatostatin receptor 2 (SSTR2) and the quantitative mRNA analysis of SSTR2 and SSTR5 were assessed in 12 tumours. The tumour proliferative fraction was assessed by immunohistochemistry for Ki-67. Eight patients (38%) had stable disease (SD) after a median follow-up of 49.5 months. Thirteen patients (62%) developed progression after a median of 18 months. Tumour progression correlated with a proliferative index>or=5% (P=0.016), weight loss (P=0.006) and absence of abdominal pain (P=0.003) at diagnosis. Other clinical (age, gender and primary tumour resection) or pathological parameters (site, size and liver metastasis) lacked significant correlation with tumour progression. No difference in the amount of SSTR2 mRNA and protein or SSTR5 mRNA was found between tumours that were stable (n=5) and seven tumours that progressed (n=7). Treatment with long-acting release octreotide was associated with stabilization of disease and a good quality of life in 38% of patients. A Ki-67 index>or=5% and/or the presence of weight loss may justify more aggressive therapy without waiting for radiologically proven progression of disease.
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PMID:Predictive factors of efficacy of the somatostatin analogue octreotide as first line therapy for advanced pancreatic endocrine carcinoma. 1715 66

Most patients who have islet cell tumors, except those who have insulinomas, present with locally advanced or metastatic disease. In contrast with patients who have adenocarcinoma of the pancreas, those who have islet cell carcinomas can achieve long-term survival even if their disease is advanced. Liver-directed therapies, somatostatin analogs, and interferon are not curative but can be used to relieve tumor-associated symptoms. Similarly, palliative chemotherapy has been used with limited success. Advances in our understanding of the molecular mechanisms underlying tumor progression have translated into intense interest in biologically based strategies to treat this disease.
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PMID:Islet cell carcinoma: neuroendocrine tumors of the pancreas and periampullary region. 1754 34

Although there has been considerable advancement in treatment techniques but still there are some illnesses that continue to exhibit a rather poor curability, such as thymoma. This report highlights the benefit of octreotide and prednisolone therapy in a 15-year-old girl, who was diagnosed with inoperable thymus carcinoma, with chemotherapy and radiotherapy being the last resort. The detection of type 2 somatostatin receptors on the surface of the tumor justified the introduction of treatment with somatostatin analog and prednisolone. Fortunately, after 6 months of this treatment, the tumor showed partial regression. However, 2 months later, somatostatin receptor negative metastases appeared; therefore, a switch over to imatinib became essential, because the tumor was CD-117 positive. Despite the therapy change, the patient's condition deteriorated owing to tumor progression.
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PMID:Advanced pediatric inoperable thymus carcinoma (type C thymoma): case report on a novel therapeutic approach. 1798 97

Somatostatin receptor scintigraphy (SRS) is a valuable method for the detection of somatostatin receptor-positive lesions. Most gastrinomas (over-)express the somatostatin receptor subtype 2 which can be targeted by In-111 labeled Octreotide. Different studies show a high sensitivity of SRS for the localization and staging of gastrinomas. SRS seems to be superior to other non-invasive imaging modalities and has been proven to significantly contribute to patient management. However, the sensitivity depends on the size and exact localization of the tumors. Smaller lesions and lesions located in the duodenum show a significantly lower sensitivity. In any case, SRS belongs to the routine imaging procedure for gastrinomas for localization and staging and can also be used for evaluation of the tumor progression.
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PMID:Imaging of gastrinomas by nuclear medicine methods. 1798 94

Hepatocellular carcinoma (HCC) is a hypervascular tumor, and tumor progression and prognosis is associated with angiogenesis. Extracellular matrix remodeling and inflammation play important roles in hepatocarcinogenesis. Some ingredients of extracellular matrix such as endostatin and sulfated polysaccharide, some immunomodulatory agents and cox-2 inhibitor suppress the angiogenesis of HCC. Because vasculogenic mimicry is associated with high tumor grade, some differentiation agents are used to inhibit antiagiogenesis. Besides suppressing the proliferation directly, somatostatin inhibits angiogenesis to suppress growth indirectly. Copper chelator prevents copper from functioning as a cofactor in angiogenesis. The renin-angiotensin system is frequently activated in patients with chronic liver diseases. Perindopril, an angiotensin converting enzyme inhibitor, inhibits angiogenesis by reducing vascular endothelial growth factor (VEGF) production. Kinase inhibitors of VEGF and epidermal growth factor receptors are expected to be of benefit for some patients. Following transarterial embolisation and/or resection, antiangiogenic therapy could prevent the recurring and metastasis. Hypoxia enhances the proliferation, suppresses the differentiation and apoptosis, and induces multidrug resistance of HCC. Because antiangiogenic therapies induce hypoxia, it should be borne in mind the side affects of antiangiogenic therapy. Because long-acting antiangiogenent are needed to control cancer, it needs more clinical studies to confirm the drug resistance of antiangiogenetic therapy.
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PMID:New strategy of antiangiogenic therapy for hepatocellular carcinoma. 1899 74

Somatostatin receptors (SSTRs) are inhibitory G-protein coupled receptors that are ubiquitously expressed in normal and cancer cells. Somatostatins (SST) are the natural ligands for SSTRs and act as inhibitory regulators of hormone secretion and proliferation. Octreotide and RC-160 (vapreotide) are two well tolerated SSTR2/SSTR5 selective somatostatin analogues (SSA) that have been used in the treatment of cancers with mixed outcomes. Loss-of-expression of SSTR2 in tumor tissues has been suggested to correlate to tumor progressions and to the poor outcomes of somatostatin analogue treatment in certain clinical trials. In this study, exogenous human SSTR2 was overexpressed in two cancer cell lines, capan-2 cells and A549 cells, which had different profiles of endogenous SSTR expression. It was shown that overexpression of SSTR2 dramatically inhibited the proliferation of SSTR2-positive and SSTR2-negative cancer cells. Further growth inhibition of these cancer cells overexpressing SSTR2 was observed by application of octreotide/RC-160 in a dose-dependent fashion. In addition, immunoassay demonstrated that SSA/SSTR2 inhibited proliferation via both cell cycle arresting and promoting apoptosis. The results suggested that SSTR2 could be a promising candidate for gene therapy for SSTR2-positive and SSTR2-negative tumors. The cellular level of SSTR2 might be a critical factor that could affect both tumor progression and the outcomes of somatostatin analogue treatment.
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PMID:Somatostatin analogues inhibit cancer cell proliferation in an SSTR2-dependent manner via both cytostatic and cytotoxic pathways. 1914 11


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