Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We demonstrated in this study that inhibition of intra-hepatic growth of colon cancer by TAC-101 is mediated by inhibition of angiogenesis. In vitro experiments showed that TAC-101 inhibited the proliferation of murine hepatic sinusoidal endothelial (HSE) cells induced by coculture with murine colon 26-L5 (L5) cells. HSE cell proliferation was also enhanced by conditioned medium of L5 cells (CM-L5), and this enhancement of proliferation was abrogated by anti-vascular endothelial growth factor antibody. CM-L5 also induced in vitro tube formation of HSE cells on Matri-gel, and this activity of CM-L5 was abrogated by TAC-101 in a concentration-dependent manner. On the other hand, p.o. administration of TAC-101 inhibited tumor-induced angiogenesis in vivo and decreased the weights of L5 tumors in the mouse liver. Reverse transcriptase-PCR analysis using in vivo tumor tissue suggested that repression of vascular endothelial growth factor expression by TAC-101 was associated with the antiangiogenic activity. TAC-101 alone and 5-fluorouracil (5-FU)/D,L-leucovorin (LV) significantly inhibited the intrahepatic growth of L5 tumors (P = 0.002 and 0.001, respectively), whereas 5-FU alone did not (P = 0.088). When TAC-101 was administered with 5-FU/LV, marked enhancement of antitumor activity was observed (95% inhibition; P<0.001). This enhanced antitumor effect was also observed in experiments using Co-3 human colon adenocarcinoma. Concurrent treatment with TAC-101 and 5-FU/LV and sequential treatment with 5-FU/LV followed by TAC-101 resulted in significant augmentation of antitumor activity against Co-3 (overall P = 0.007 and 0.015, respectively). These findings indicate that TAC-101 inhibits tumor angiogenesis and suggest that it may be effective against hepatic metastasis of colon cancer.
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PMID:Inhibition of angiogenesis and intrahepatic growth of colon cancer by TAC-101. 1049 97

The vascular endothelial growth factor is produced by a large variety of human tumors, including melanoma, in which it appears to play an important role in the process of tumor-induced angiogenesis. Little information is available on the role of placenta growth factor, a member of the vascular endothelial growth factor family of cytokines, in tumor angiogenesis, even though placenta growth factor/vascular endothelial growth factor heterodimers have been recently isolated from tumor cells. To investigate the role of placenta growth factor and vascular endothelial growth factor homodimers and heterodimers in melanoma angiogenesis and growth, 19 human melanoma cell lines derived from primary or metastatic tumors were characterized for the expression of these cytokines and their receptors. Release of placenta growth factor and vascular endothelial growth factor polypeptides into the supernatant of human melanoma cells was demonstrated. Reverse transcriptase polymerase chain reaction analysis showed the presence of mRNAs encoding at least three different vascular endothelial growth factor isoforms (VEGF(121), VEGF(165), and VEGF(189)) and transcripts for two placenta growth factor isoforms (PlGF-1 and PlGF-2) in human melanoma cells. In addition, placenta growth factor expression in human melanoma in vivo was detected by immunohistochemical staining of tumor specimens. Both primary and metastatic melanoma cells were found to express the mRNAs encoding for vascular endothelial growth factor and placenta growth factor receptors (KDR, Flt-1, neuropilin-1, and neuropilin-2), and exposure of melanoma cells to these cytokines resulted in a specific proliferative response, supporting the hypothesis of a role of these angiogenic factors in melanoma growth. J Invest Dermatol 115:1000-1007 2000
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PMID:Human melanoma cells secrete and respond to placenta growth factor and vascular endothelial growth factor. 1112 Nov 33

Angiogenesis or new vessel formation is an essential component in the growth and progression of neoplasms and there is growing evidence of its importance in hematological malignancies including multiple myeloma (MM). Vascular endothelial growth factor (VEGF) is believed to play a role in tumor angiogenesis. We studied the expression of VEGF and its receptors (VEGFR1 or Flt-1 and VEGFR2 or Flk-1/KDR) by myeloma cell lines and plasma cells isolated from patients, using different methods. VEGF expression by the plasma cells was demonstrated by immunohistochemistry in 18 of 20 patients with MM. Enzyme-linked immunosorbent assay demonstrated VEGF secretion in all six different myeloma cell lines studied. Five patient marrow samples and seven different myeloma cell lines were then studied for VEGF mRNA expression by reverse-transcriptase polymerase chain reaction (RT-PCR), which was positive in all. We further evaluated the expression of both VEGFR1 and VEGFR2 in different myeloma cell lines and five sorted myeloma bone marrow samples by RT-PCR. All the myeloma cell lines expressed VEGFR1 and three of the cell lines expressed VEGFR2. VEGFR1 expression was detected in all and VEGFR2 in all but one of the sorted marrow samples. Increased expression of VEGF by the myeloma cells taken in the context of the suspected prognostic value of marrow angiogenesis suggests a pathogenetic role for this cytokine and presence of its receptors on myeloma cells points toward an autocrine mechanism. Demonstration of the presence of VEGFR2 in our study provides a potential biological explanation for the preclinical activity observed with VEGFR2 inhibitors.
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PMID:Expression of VEGF and its receptors by myeloma cells. 1451 53

Tissue factor (TF) is a transmembrane glycoprotein that serves as the prime initiator of blood coagulation and plays a critical role in thrombosis and hemostasis. In addition, a variety of tumor cells overexpress cell-surface TF, which appears to be important for tumor angiogenesis and metastasis. To elucidate the mechanism involved in the upregulation of TF in human tumor cells, a comprehensive analysis of TF mRNA from various normal and tumor cells was performed. The results of these studies indicate that, in addition to possessing a normal full-length TF transcript and minor levels of an alternatively spliced transcript known as alternatively-spliced tissue factor (asTF), human tumor cells express additional full-length TF transcripts that are also generated by alternative splicing. Reverse transcriptase-polymerase chain reaction (RT-PCR) and 5'-rapid amplification of cDNA ends- (5'-RACE) based analyses of cytoplasmic RNA from normal and tumor cells revealed that there is alternative splicing of the first intron between exon I and exon II resulting in 2 additional TF transcripts. One of the transcripts has an extended exon I with inclusion of most of the first TF intron (955 bp), while the second transcript is formed by the insertion of a 495 bp sequence, referred to as exon IA, derived from an internal sequence of the first intron. The full length TF transcript with alternatively spliced novel exon IA, referred to as alternative exon 1A-tissue factor (TF-A), represented approximately 1% of the total TF transcripts in normal cells, but constituted 7-10% of the total TF transcript in tumor cells. Quantitative real-time RT-PCR analysis indicated that cultured human tumor cells contain 10-25-fold more copy numbers of TF-A in comparison to normal, untransformed cells. We propose that high-level expression of the novel TF-A transcript, preferentially in tumor cells, may have utility in the diagnosis and staging of a variety of solid tumors.
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PMID:Identification of a novel human tissue factor splice variant that is upregulated in tumor cells. 1621 71

Previous studies have shown that interleukin-24 (IL-24; mda-7) as a novel tumor suppressor gene has tumor-suppressive activity against a broad spectrum of human cancers. However, the therapeutic effect of the recombinant human IL-24 (rhIL-24) protein purified from prokaryotic cells on human lung cancers has not been reported. In this study, we cloned the human gene coding for IL-24 from lipopolysaccharide-activated human peripheral blood mononuclear cells (PBMCs) by reverse-transcriptase polymerase chain reaction and constructed an expression vector pBV220-IL-24. We then transfected Escherichia coli DH5alpha with pBV220-IL-24. The soluble rhIL-24 was obtained from purified insoluble inclusion bodies of transfected cells by a denaturing and renaturing process. We demonstrated that the purified soluble rhIL-24 protein with 18.5 kappaDa was capable of (1) inducing in vitro apoptosis of A549 lung carcinoma cells; (2) activating PBMCs to secrete cytokines such as IL-6, tumor necrosis factor-alpha, and interferon-gamma; (3) inhibiting the formation of blood capillaries on chicken embryonic allantois and in vivo tumor angiogenesis; and (4) inhibiting A549 lung tumor cell growth in vitro and in vivo. Therefore, our results indicate its potent suppressive effect on human lung carcinoma cell line and warrant its further investigation for therapeutic application against human lung cancer.
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PMID:Recombinant human IL-24 suppresses lung carcinoma cell growth via induction of cell apoptosis and inhibition of tumor angiogenesis. 1859 64