Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This commentary proposes the working hypothesis that transforming growth factor-beta (TGF-beta) can play two different and opposite roles with respect to the process of malignant progression. During the earliest stages of carcinogenesis, TGF-beta can act as potent tumor suppressor and may mediate the actions of chemopreventive agents such as retinoids and tamoxifen. However, at some point during the development and progression of malignant neoplasms, bioactive TGF-betas make their appearance in the tumor microenvironment and the tumor cells appear to escape from TGF-beta-dependent growth arrest. Evidence is accumulating rapidly that this TGF-beta resistance is the consequence of inactivating mutations in any one of the genes that encode signaling intermediates, which include the type I and type II TGF-beta receptors, as well as several Smad proteins. The potential implications of the phenotypic switch from TGF-beta sensitive to TGF-beta resistance that occurs during carcinogenesis for cancer prevention and treatment are discussed.
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PMID:Transforming growth factor-beta and cancer: a love-hate relationship? 949 50

During postnatal development, the formation of new blood vessels is possible only through angiogenesis. The initial growth of solid neoplasms, including childhood brain tumors, during the genetically determined stages of carcinogenesis, even at clinically undetectable sizes (a few mm3), depends upon the continuous formation of new blood capillaries [i.e. neovascularization (NV)/neoplasm-related angiogenesis (NRA)]. The generation of a malignant, invasive cellular immunophenotype (CIP) and distant metastases are also NRA-dependent processes. Endothelial cells undergo rapid proliferation during brain tumor related angiogenesis. Human endoglin (CD105/EDG), is a homodimeric cell surface component of the transforming growth factor-beta (TGF-beta) type I receptor complex and is also a proliferation-associated antigen (PAA) expressed at high density on endothelial cells. Formalin fixed, paraffin-wax embedded (3-5 microns thick), as well as frozen tissue sections (6 microns thick) of 62 childhood brain tumors [34 medulloblastomas (MEDs) and 28 astrocytomas (ASTRs)], were employed for the assessment of EDG expression. Both an indirect, four-step, alkaline phosphatase (AP) conjugated, biotin-streptavidin based (or a diamino-benzidine [DAB]) conjugated immunoperoxidase antigen detection technique were employed, utilizing the SN6h anti-EDG monoclonal antibody (DAKO Corp.). Another antigen detection method, based on the Histogold (Zymed) reaction was also employed using the same antibody on formalin fixed, paraffin-wax embedded tissues. Strong expression (A; +3 to +4) of EDG on endothelial cells and demonstrated in all 62 childhood brain tumor cases. The most striking feature of the newly formed tumor-related capillaries was the presence of a markedly enlarged perivascular space. Blood vessels in several normal human tissues (cortex, cerebellum, thymus, tonsil, spleen, lymph node, skin) used as control tissues contained significantly lower levels of EDG (B and mostly C; +/- to +), in accordance with the extremely slow turnover rate of normal endothelial cells. A close apposition between the capillaries and the adjacent parenchyma was also observed. Brain tumors, especially glioblastoma, are among the most vascularized human neoplasms, and thus are candidates for antiangiogenic therapy. VEGF/PF-R1 (flt-1) and VEGF/PF-R2 (flk-1) are formed de novo in a glioma progression-dependent manner. Further studies should substantiate the importance of EDG in the earliest possible detection, diagnosis and NRA inhibition-based treatment of mammalian solid neoplasms, especially childhood brain tumors.
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PMID:Upregulation of endoglin (CD105) expression during childhood brain tumor-related angiogenesis. Anti-angiogenic therapy. 967 60

The transforming growth factor-beta (TGF-beta) type II receptor (RII) is a colon cancer suppressor gene that is inactivated by mutation in 90% of human colon cancers arising via the microsatellite instability (MSI) pathway of carcinogenesis. To determine the pathophysiological consequence of RII mutations, we have determined the timing of their onset among 22 MSI human colon adenomas of varying stages. No RII mutations were detected in any early MSI adenoma, including all those with simple tubular or villous histology. The earliest RII mutation detected was in a region of high-grade dysplasia but was absent from the surrounding simple adenoma. Six additional RII mutations were all found in highly progressed adenomas that contained regions of frankly invasive adenocarcinoma. These RII mutations were detected in both the advanced adenomas and their adjacent regions of carcinoma. RII mutation is a late event in MSI adenomas and correlates tightly with progression of these adenomas to cancer.
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PMID:Mutation of the type II transforming growth factor-beta receptor is coincident with the transformation of human colon adenomas to malignant carcinomas. 967 77

The commencement of the complex process of carcinogenesis, and subsequent, rapid tumor growth and progression of mammalian neoplasms, including malignant melanomas, depends upon the continuous de novo formation of capillaries [i.e. neovascularization (NV)/neoplasm-related angiogenesis (NRA)]. The generation of a dedifferentiated, malignant, highly invasive cellular immunophenotype (CIP) and distant metastases, as aspects of constant neoplastic progression, are also NRA-dependent processes. Endothelial cells undergo rapid proliferation during malignant melanoma (MM) related angiogenesis. Human endoglin (CD105/EDG), is a homodimeric cell surface component of the transforming growth factor-beta (TGF-beta) type I receptor complex and is also a proliferation-associated antigen (PAA) expressed at high density on endothelial cells. Formalin fixed, paraffin-wax embedded, tissue sections (3-5 microns thick) of 25 MMs were employed for the assessment of EDG expression. An indirect, four-step, alkaline phosphatase (AP) (or diamino-benzidine [DAB]) conjugated, biotin-streptavidin based, antigen detection technique, employing the SN6h anti-EDG monoclonal antibody was conducted. Zymed's Histogold System was also utilized for immunocytological antigen detection. Strong expression (A; +3 to +4) of EDG on endothelial cells was demonstrated in all MM cases. The most striking feature of the newly formed neoplasm-related capillaries was the presence of an enlarged perivascular space. Blood vessels in several normal human tissues (cortex, cerebellum, thymus, tonsil, spleen, lymph node, skin) used as control tissues contained significantly lower levels of EDG (B and mostly C; +/- to +), in accordance with the extremely slow turnover rate of normal endothelial cells. Furthermore, a close apposition between the capillaries and the adjacent parenchyma was observed in these normal controls. MMs, like most mammalian neoplasms, are characterized by extensive neovascularization, and thus are candidates for anti-angiogenic therapy. Further studies should substantiate the importance of EDG expression in the earliest possible detection, diagnosis and NRA inhibition-based treatment of solid tumors, including MMs. The importance of TGF-beta in all of the various aspects of neoplastic transformation, as well as malignant disease progression should also be studied more extensively in the future.
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PMID:Immunocytochemical detection of endoglin is indicative of angiogenesis in malignant melanoma. 970 32

Experimental data suggest that dysregulation of growth factors and the cognate receptors may play an important role in hepatocarcinogenesis. The objective of the present study was to characterize the expression of two hepatotrophic growth factor/receptor systems [transforming growth factor-alpha/epidermal growth factor receptor (TGF-alpha/EGFR) and hepatocyte growth factor/c-met receptor (HGF/c-met)], both of which are implicated in the development of human liver tumors. In addition, we have analyzed the expression of transforming growth factor-beta receptor type II (TGF-beta-RII) and p53, genes associated with growth inhibition and tumor suppression, respectively. Surgical biopsy specimens from 86 human hepatocellular carcinomas were analyzed. TGF-alpha was overexpressed in 17%, equally expressed in 21%, and down-regulated in 62% of the hepatocellular carcinomas when compared to the surrounding hepatic tissue. No major changes were found with EGFR expression. HGF was over-expressed in 33% and down-regulated in 21% of the tumors. The c-met receptor was overexpressed in 20%, equally expressed in 48%, and down-regulated in 32% of the neoplasms. In contrast, TGF-beta-RII was overexpressed in only 8%, equal in 42%, and down-regulated in 50% of tumors. Nuclear staining of p53, indicative of a mutation(s), was observed in the great majority of the tumors (80%), whereas no nuclear p53 was detected in peritumoral tissues. Interestingly, simultaneous down-regulation of c-met and TGF-beta-RII was observed in 23% of the hepatocellular carcinomas, 85% of which also showed nuclear p53 staining. Taken together, our data suggest that down-regulation of c-met and TGF-beta-RII may, together with p53 mutations, play a significant role in human liver carcinogenesis.
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PMID:Analysis of transforming growth factor (TGF)-alpha/epidermal growth factor receptor, hepatocyte growth Factor/c-met,TGF-beta receptor type II, and p53 expression in human hepatocellular carcinomas. 981 84

The commencement of the complex process of carcinogenesis, and subsequent, rapid tumor growth and progression of mammalian neoplasms, including breast carcinomas (BCs), depends upon the continuous de novo formation of capillaries [i.e. neovascularization (NV)/neoplasm-related angiogenesis (NRA)]. The generation of a malignant, invasive cellular immunophenotype (CIP) and distant metastases, as aspects of tumor progression, are also NRA-dependent processes. Endothelial cells undergo rapid proliferation during mammary carcinoma-related angiogenesis. Human endoglin (CD105/EDG), is a homodimeric cell surface component of the transforming growth factor-beta (TGF-beta) type I receptor complex and is also a proliferation-associated antigen (PM) expressed at high density on endothelial cells. Formalin fixed, paraffin-wax embedded, tissue sections (3-5 microns thick) of 15 BCs were employed for the assessment of EDG expression. An indirect, four-step, alkaline phosphatase (AP) (or diamino-benzidine [DAB]) conjugated, biotin-streptavidin based, antigen detection technique, employing the SN6h anti-EDG monoclonal antibody was conducted. Zymed's Histogold System was also utilized for immunocytological antigen detection. Strong expression (A; ++ + to ++ ++) of EDG on endothelial cells was demonstrated in all 15 BC cases. The most striking feature of the newly formed neoplasm-related capillaries was the presence of an enlarged perivascular space. Blood vessels in several normal human tissues (cortex, cerebellum, thymus, tonsil, spleen, lymph node, skin) used as control tissues contained significantly lower levels of EDG (B and mostly C; +/- to +), in accordance with the extremely slow turnover rate of normal endothelial cells. Furthermore, a close apposition between the capillaries and the adjacent parenchyma was observed in these normal controls. BCs, as most mammalian neoplasms, are characterized by extensive neovascularization and thus are candidates for anti-angiogenic therapy. Further studies should substantiate the importance of EDG expression in the earliest possible detection, diagnosis and NRA inhibition-based treatment of solid tumors, including BCs.
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PMID:Over-expression of endoglin (CD105): a marker of breast carcinoma-induced neo-vascularization. 985 49

Hepatocyte growth factor (HGF) and c-met proto-oncogene product (c-Met) have varied biological functions in different tissues and have been implicated in mitogenic, motogenic and morphogenic responses in both organ regeneration and carcinogenesis. Some studies have suggested that the overexpression of c-Met and epidermal growth factor receptor (EGFR) are associated with growth advantage, while transforming growth factor-beta receptor II (TGF beta R II) is associated with growth disadvantage of human prostatic adenocarcinoma. However, it is unclear if the expression of c-Met correlates with the expression of EGFR and TGF beta R II, and with the proliferative status of human prostatic adenocarcinoma. Using immunohistochemical staining with anti-c-Met (C-12), anti-EGFR (NCL-EGFR) and anti-TGF beta R II (L-21) antibodies, we determined the frequency of expression of c-MET, EGFR, and TGF beta R II respectively in a series of 134 radical prostatectomy specimens. We evaluated the relationship between the expression of these receptors and clinicopathological characteristics. Overall, c-Met immunostaining was detected in 54 of 134 (40.3%) cases, EGFR in 45 (33.6%) and TGF beta R II in 64 (48.4%). The overexpression of c-Met was significantly more common in poorly differentiated (P < 0.0001) and in the diffusely infiltrated specimens (P < 0.0005). In contrast, TGF beta R II was significantly overexpressed in the well differentiated specimens (P < 0.0001) and associated negatively with c-Met (P < 0.0001). Overall, these data suggest that c-Met/HGF receptor and TGF beta R II overexpression may be involved in the differentiation of human prostatic adenocarcinoma, c-Met with de-differentiation and TGF beta R II with differentiation.
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PMID:Overexpression of c-Met/hepatocyte growth factor receptors in human prostatic adenocarcinoma. 987 67

A genome-wide instability at simple repeat sequences characterizes gastrointestinal and endometrial cancers of the microsatellite mutator phenotype (MMP). The genes encoding transforming growth factor-beta receptor type II (TGFbetaRII), insulin-like growth factor II receptor (IGFIIR), Bcl-2 associated X protein (BAX), hMSH3 and hMSH6 have simple repeat sequences in their coding regions. Consequently, mutations in the single repeat sequences in these genes provide one major route for carcinogenesis in these cancers. We examined 43 non-small cell lung carcinomas and 16 small cell carcinomas for frameshift mutations in simple repeat sequences of TGFbetaRII, IGFIIR, BAX, hMSH3 and hMSH6. In addition, MMP was assessed using a primer set for BAT-26. None of 59 lung cancers exhibited frameshift mutations or MMP. It is concluded that somatic frameshift mutations in these genes and MMP do not constitute important mechanisms in lung carcinogenesis. The possibility of some sort of genetic instability undetectable as a form of MMP cannot be precluded.
Carcinogenesis 1999 Mar
PMID:Frameshift mutations in TGFbetaRII, IGFIIR, BAX, hMSH3 and hMSH6 are absent in lung cancers. 1019 May 68

Decorin is a member of the small leucine-rich proteoglycan (SLRP) gene family that has recently become a focus in various areas of cancer research. The decorin protein consists of a core protein and a covalently linked glycosaminoglycan chain. Decorin binds to collagens type I, II and IV in vivo and promotes the formation of fibers with increased stability and changes in solubility. Further, the decorin core protein binds to growth factors, including transforming growth factor-beta (TGF-beta), to other intercellular matrix molecules such as fibronectin and thrombospondin, and to the decorin endocytosis receptor. Decorin may directly interfere with the cell cycle via the induction of p21WAF1/CIP1 (p21), a potent inhibitor of cyclin-dependent kinases (CDKs). Here, we discuss interactions of decorin with TGF-beta and with p21, both of which are relevant to carcinogenesis and tumor progression. TGF-beta is released by tumors of various histogenetic origins and promotes immunosuppression in the host and tumor immune escape by induction of growth arrest and apoptosis in immune cells, by downregulation of MHC II antigen expression and by changes in the cytokine release profiles of immune and tumor cells. Moreover, TGF-beta may modulate tumor growth in an autocrine and paracrine fashion, may mediate drug resistance, and may facilitate tumor angiogenesis. Decorin binds to TGF-beta, thus inhibiting its bioactivity, and is a direct or indirect negative modulator of TGF-beta synthesis. Ectopic expression of decorin results in the regression of rat C6 gliomas, an antineoplastic effect attributed to the reversal of TGF-beta-induced immunosuppression. On the other hand, de novo expression of decorin in colon cancer cells and some other tumor cells, even though not in glioma cells, results in an upregulation of p21 expression and a cell cycle arrest, presumably in a TGF-beta-independent manner. Decorin expression is downregulated in many tumors but upregulated in the peritumoral stroma. By virtue of its growth regulatory and immunomodulatory properties, decorin promises to become a novel target for the experimental therapy of human cancers.
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PMID:Transforming growth factor-beta and p-21: multiple molecular targets of decorin-mediated suppression of neoplastic growth. 1038 66

It is now well accepted that (-)-epigallocatechin gallate (EGCG) inhibits carcinogenesis in the digestive tract in rodents. To understand the mechanisms of anticarcinogenesis, we first studied growth inhibition by EGCG in human stomach cancer cell lines established at Seoul National University (SNU cell lines). Inhibition by EGCG of [3H]thymidine incorporation into eight SNU cell lines was examined, in relation to transforming growth factor-beta (TGF-beta) responsiveness. Various tea polyphenols derived from green tea and black tea induced growth inhibition and apoptosis of human stomach cancer cell line KATO III, and inhibition of tumor necrosis factor-alpha (TNF-alpha) release from the cells, in the order of (-)-epicatechin gallate (ECG), EGCG, (-)-epigallocatechin (EGC), teaflavins (TF) and (-)-epicatechin (EC). In addition, we demonstrated that EGCG inhibited TNF-alpha gene expression in KATO III cells, as well as okadaic acid-induced AP-1 and NF-kappa B activation. The inhibitory potencies of EGCG for AP-1 and NF-kappa B binding to DNA were different between KATO III cells and mouse fibroblast cell line BALB/3T3. Thus, EGCG and other tea polyphenols may interact with various transcription factors, in addition to AP-1 and NF-kappa B, in nuclei of various cells, resulting in inhibition of TNF-alpha gene expression and TNF-alpha release.
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PMID:Mechanistic aspects of green tea as a cancer preventive: effect of components on human stomach cancer cell lines. 1047 Feb 85


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