angiogenin and Colonic-Neoplasms

Metastasis of colorectal cancer (CRC) is the leading cause of CRC-associated mortality. Angiogenin (ANG), a member of the ribonuclease A superfamily, not only activates endothelial cells to induce tumor angiogenesis, but also targets tumor cells to promote cell survival, proliferation and/or migration. However, its clinical significance and underlying mechanism in CRC metastasis are still largely unknown. Here, we reported that ANG was upregulated in CRC tissues and associated with metastasis in CRC patients. We then revealed that ANG enhanced CRC growth and metastasis in both in vitro and in vivo systems. Intriguingly, we characterized a bunch of tRNA-derived stress-induced small RNAs (tiRNAs), produced through ANG cleavage, that was enriched in both CRC tumor tissues and highly metastatic cells, and functioned in ANG-promoted CRC metastasis. Moreover, higher level of a 5'-tiRNA from mature tRNA-Val (5'-tiRNA-Val) was observed in CRC patients and was correlated with tumor metastasis. Taken together, we propose that a novel ANG-tiRNAs-cell migration and invasion regulatory axis promotes CRC metastasis, which might be of potential target for CRC diagnosis and treatment.

Topics: 5' Untranslated Regions; Animals; Case-Control Studies; Cell Movement; Colonic Neoplasms; Gene Knockout Techniques; Heterografts; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Neoplasm Invasiveness; Neoplasm Metastasis; Neovascularization, Pathologic; Ribonuclease, Pancreatic; RNA, Transfer; Up-Regulation

Angiogenesis is important in cancer progression and can be influenced by tumor-associated myofibroblasts. We addressed the hypothesis that glucocorticoids indirectly affect angiogenesis by altering the release of pro-angiogenic factors from colon cancer-derived myofibroblasts. Our study shows that glucocorticoids reduced prostanoids, urokinase-type plasminogen activator (uPA) and angiopoietin-like protein-2 (ANGPTL2) levels, but increased angiogenin (ANG) in supernatant from human CT5.3hTERT colon cancer-derived myofibroblasts. Conditioned medium from solvent- (CMS) and dexamethasone (Dex)-treated (CMD) myofibroblasts increased human umbilical vein endothelial cell (HUVEC) proliferation, but did not affect expression of pro-angiogenic factors or tube-like structure formation (by HUVECs or human aortic ECs). In a HUVEC scratch assay CMS-induced acceleration of wound healing was blunted by CMD treatment. Moreover, CMS-induced neovessel growth in mouse aortic rings ex vivo was also blunted using CMD. The latter effect could be ascribed to both Dex-driven reduction of secreted factors and potential residual Dex present in CMD (indicated using a dexamethasone-spiked CMS control). A similar control in the scratch assay, however, revealed that altered levels of factors in the CMD, and not potential residual Dex, were responsible for decreased wound closure. In conclusion, our results suggest that glucocorticoids indirectly alter endothelial cell function during tumor development in vivo.

Topics: Angiogenesis Inhibitors; Angiopoietin-Like Protein 2; Angiopoietin-like Proteins; Angiopoietins; Animals; Cancer-Associated Fibroblasts; Cell Line, Transformed; Cell Movement; Cell Proliferation; Colonic Neoplasms; Culture Media, Conditioned; Dexamethasone; Endothelial Cells; Glucocorticoids; Human Umbilical Vein Endothelial Cells; Humans; Male; Mice, Inbred C57BL; Myofibroblasts; Neovascularization, Pathologic; Neovascularization, Physiologic; Paracrine Communication; Ribonuclease, Pancreatic; Signal Transduction; Stromal Cells; Time Factors; Tissue Culture Techniques; Tumor Microenvironment; Urokinase-Type Plasminogen Activator

The present study aimed to examine changes in the expression of angiogenic growth factors in vascular endothelial cells isolated from colon cancer after bevacizumab treatment in vitro, and to explore a potential mechanism of their self-regulation as a possible mechanism for antiangiogenic therapy failure in clinics. Vascular endothelial cells were isolated from tumors of colon cancer patients and transfected with recombinant adeno-associated virus type 2-vascular endothelial growth factor (VEGF) or pGIPZ-VEGF RNA interference in order to upregulate or downregulate VEGF expression. Changes in VEGF expression and its correlation with the expression of angiogenesis-related factors, including basic fibroblast growth factor (bFGF) and angiopoietin 1 (ANG1), after treatment with bevacizumab in vitro, were investigated. The results showed that in cells with VEGF overexpression, bFGF and ANG1 were downregulated, whereas in cells in which VEGF was knocked down, upregulation of bFGF and ANG1 was detected. In cells treated with bevacizumab, a significant upregulation of VEGF and downregulation of bFGF and ANG1 were observed. Our data indicate that after bevacizumab treatment, a potential self-regulating mechanism of angiogenic growth factors in colon cancer-derived endothelial cells is activated, which may explain why current antiangiogenic therapy with bevacizumab has limited effects in prolonging the survival of colon cancer patients.

Topics: Angiogenesis Inhibitors; Bevacizumab; Cells, Cultured; Colonic Neoplasms; Endothelial Cells; Endothelium, Vascular; Feedback, Physiological; Fibroblast Growth Factor 2; Gene Expression Regulation, Neoplastic; Humans; Middle Aged; Ribonuclease, Pancreatic; Vascular Endothelial Growth Factor A

Tumor cells trigger angiogenesis through overexpression of various angiogenic factors including vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang1). Therefore, inhibition of the expression of both VEGF and Ang1, the initial step of tumor angiogenesis, is a promising strategy for cancer chemoprevention and therapy. Grape seed proanthocyanidins (GSPs) are widely consumed dietary supplements that have antitumor activity. Due to their polymeric structure, GSPs are poorly absorbed along the gastrointestinal tract and can reach the colon at high concentrations, allowing these chemicals to act as chemopreventive agents for colon cancer. In the present study, we found that GSPs inhibited colon tumor-induced angiogenesis and, thus, the growth of colon tumor xenografts on the chick chorioallantoic membranes. The mechanisms of their action were related to inhibiting the expression of both VEGF and Ang1 through scavenging reactive oxygen species. Previous studies have demonstrated that the chemopreventive effects of GSPs on colon cancer are associated with their growth inhibitory and apoptosis-inducing effects. Our results demonstrate another mechanism by which GSPs inhibit colon tumor growth, which will be helpful for developing GSPs as a pharmacologically safe angiopreventive agent against colorectal cancer.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Cell Movement; Cell Survival; Chick Embryo; Chorioallantoic Membrane; Colonic Neoplasms; Culture Media, Conditioned; Grape Seed Extract; Humans; Neovascularization, Pathologic; Proanthocyanidins; Reactive Oxygen Species; Ribonuclease, Pancreatic; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Gum Arabic (GA), a nutrient from dried exudate of Acacia senegal, is widely used as emulsifier and stabilizer. It stimulates sodium and water absorption in diarrhea. This study explored the effects of GA in colonic tissue. Mice were treated with GA (10% wt/vol) in drinking water and gene array was performed. As GA modified several tumor-relevant genes, chemical cancerogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by 3 cycles of 3% dextrane sodium sulphate in drinking water) was induced with or without GA treatment. Within 4 days, GA treatment decreased the colonic transcript levels of the angiogenetic factors angiogenin 1, angiogenin 3, and angiogenin 4 by 78 +/- 18%, 88 +/- 15%, and 92 +/- 13%, respectively (n = 5 each), and of further genes including CD38 antigen, aquaporin4, interleukin18, vav-3-oncogene, gamma(+)-amino acid transporter, sulfatase1, ubiquitinD, and chemokine ligand5. According to Western blotting, GA treatment similarly decreased angiogenin protein expression, and according to immunohistochemistry, it decreased ss-catenin expression. Chemical cancerogenesis resulted in multiple colonic tumors within 12 wk. GA treatment (10% wt/wt) in drinking water significantly decreased the number of tumors by 70%. The observations disclose a powerful anticarcinogenic effect of GA. The nutrient could thus be used for the prophylaxis against colon carcinoma particularly in individuals at enhanced risk.

Topics: 1,2-Dimethylhydrazine; Animals; Anticarcinogenic Agents; Colonic Neoplasms; Down-Regulation; Female; Gum Arabic; Male; Mice; Mice, Inbred BALB C; Ribonuclease, Pancreatic; RNA, Messenger

Apolipoprotein(a) (apo(a)) contains tandemly repeated kringle domains that are closely related to plasminogen kringle 4, followed by a single kringle 5-like domain and an inactive protease-like domain. Recently, the anti-angiogenic activities of apo(a) have been demonstrated both in vitro and in vivo. However, its effects on tumor angiogenesis and the underlying mechanisms involved have not been fully elucidated. To evaluate the anti-angiogenic and anti-tumor activities of the apo(a) kringle domains and to elucidate their mechanism of action, we expressed the last three kringle domains of apo(a), KIV-9, KIV-10, and KV, in Escherichia coli. The resultant recombinant protein, termed rhLK68, exhibited a dose-dependent inhibition of basic fibroblast growth factor-stimulated human umbilical vein endothelial cell proliferation and migration in vitro and inhibited the neovascularization in chick chorioallantoic membranes in vivo. The ability of rhLK68 to abrogate the activation of extracellular signal-regulated kinases appears to be responsible for rhLK68-mediated anti-angiogenesis. Furthermore, systemic administration of rhLK68 suppressed human lung (A549) and colon (HCT-15) tumor growth in nude mice. Immunohistochemical examination and in situ hybridization analysis of the tumors showed a significant decrease in the number of blood vessels and the reduced expression of vascular endothelial growth factor, basic fibroblast growth factor, and angiogenin, indicating that suppression of angiogenesis may have played a significant role in the inhibition of tumor growth. Collectively, these results suggest that a truncated apo(a), rhLK68, is a potent anti-angiogenic and anti-tumor molecule.

Topics: Allantois; Animals; Apolipoproteins A; Cell Division; Cell Movement; Cells, Cultured; Chickens; Chorion; Colonic Neoplasms; Dose-Response Relationship, Drug; Endothelial Growth Factors; Endothelium, Vascular; Escherichia coli; Female; Fibroblast Growth Factor 2; Gene Expression; Humans; In Situ Hybridization; Intercellular Signaling Peptides and Proteins; Kringles; Lung Neoplasms; Lymphokines; Mice; Mice, Inbred BALB C; Mice, Nude; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Neoplasm Transplantation; Neoplasms; Neovascularization, Pathologic; Neovascularization, Physiologic; Peptide Fragments; Phosphorylation; Recombinant Proteins; Ribonuclease, Pancreatic; RNA, Messenger; Tumor Cells, Cultured; Umbilical Veins; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Topics: Angiogenesis Inducing Agents; Animals; Chickens; Chromatography, Ion Exchange; Cloning, Molecular; Colonic Neoplasms; Escherichia coli; Humans; Indicators and Reagents; Recombinant Proteins; Ribonuclease, Pancreatic; RNA, Transfer; Substrate Specificity; Tumor Cells, Cultured; Wound Healing

A noncytotoxic neutralizing monoclonal antibody (mAb), 26-2F, to human angiogenin (Ang), a potent inducer of neovascularization, has been reported to prevent or delay the establishment of HT-29 human tumor xenografts in athymic mice. In the present study the tumor model was modified to increase sensitivity to Ang antagonists to facilitate further investigations and comparisons of their capacity to inhibit tumor growth. An increase in the percentage of tumor-free mice from 10-25% to 65% is observed in this modified model after treatment with mAb 26-2F. An additional neutralizing mAb, 36u, that interacts with a different epitope on Ang similarly prevents the appearance of tumors, both alone and in combination with mAb 26-2F. In those tumors that develop in mice treated with these agents, the number of vascular elements is reduced. Actin, an Ang antagonist that unlike the mAbs binds both human and mouse Ang, also prevents the establishment of tumors while exhibiting no toxic effects at daily doses > 50 times the molar amount of circulating mouse Ang. Ang antagonists also inhibit the appearance of tumors derived from two other Ang-secreting human tumor cell lines--i.e., A549 lung adenocarcinoma and HT-1080 fibrosarcoma. These results demonstrate that inhibition of the action of Ang is an effective therapeutic approach for the treatment of malignant disease.

Topics: Actins; Angiogenesis Inducing Agents; Animals; Antibodies, Monoclonal; Carcinoma; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Interactions; Fibrosarcoma; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Neoplasms, Experimental; Proteins; Ribonuclease, Pancreatic; Survival Analysis

Human angiogenin is an excellent substrate for the adhesion of HT-29 human colon adenocarcinoma cells. These cells adhere more quickly to human angiogenin than to fibronectin, laminin, collagen I, and collagen IV. Anti-angiogenin antibodies and the angiogenesis inhibitors platelet factor-4 and placental ribonuclease inhibitor prevent adhesion of HT-29 cells to angiogenin. Calcium and magnesium ions are not required for adhesion and Arg-Gly-Asp-Ser has no effect, indicating that the interaction is integrin-independent. Instead, adhesion seems to involve a heparan/chondroitin sulfate proteoglycan. Treatment of the cells with heparinase or heparitinase decreases HT-29 cell adhesion onto angiogenin but not onto collagen I. Moreover, cell adhesion is decreased by the presence of heparin or chondroitin sulfates and by preincubation of the cells with inhibitors of proteoglycan synthesis or secretion. In addition, angiogenin binds tightly to heparin-Sepharose, requiring 0.78 M NaCl for elution. Angiogenin-affinity chromatography of a 35S-, 3H-labeled HT-29 cell fraction enriched in cell-surface proteoglycans yields a single, heparinase-sensitive component of apparent molecular mass > 200 kDa, as detected by autoradiography after SDS-polyacrylamide gel electrophoresis. These results suggest that angiogenin could be an effective substrate for tumor cell adhesion during metastasis and may provide a basis for the design of inhibitors of this process.

Topics: Adenocarcinoma; Calcium; Cell Adhesion; Cell Adhesion Molecules; Colonic Neoplasms; Glycosaminoglycans; Humans; In Vitro Techniques; Magnesium; Neovascularization, Pathologic; Oligopeptides; Proteins; Proteoglycans; Ribonuclease, Pancreatic; Tumor Cells, Cultured

Using digoxigenin-labelled, synthetic oligonucleotide probe cocktails of angiogenin and bFGF genes, the expression of the two genes was observed by in situ hybridization in ten colonic adenocarcinomas, seven gastric adenocarcinomas, and four hepatocellular carcinomas. The angiogenin gene was expressed in eight of the ten cases of colonic adenocarcinoma and in all of the four cases where dysplastic glands were found. Angiogenin expression was evident in four of the seven cases of gastric adenocarcinoma. bFGF expression was detected in only five of the seven gastric carcinoma cases. The mRNAs for angiogenin and bFGF were mainly cytoplasmic in distribution and were only occasionally seen in the nuclei of the positive cells. Neither the angiogenin gene mRNA nor the bFGF mRNA was expressed in the four cases of hepatocellular carcinoma. It is postulated that the angiogenin gene may play an important role in angiogenesis in colonic adenocarcinomas; in gastric cancers, both angiogenin and bFGF were involved in this process. For hepatocellular carcinomas, neither angiogenin nor bFGF production appeared to be related to angiogenesis.

Topics: Adenocarcinoma; Angiogenesis Inducing Agents; Carcinoma, Hepatocellular; Colonic Neoplasms; Fibroblast Growth Factor 2; Gastrointestinal Neoplasms; Humans; In Situ Hybridization; Liver Neoplasms; Neoplasm Proteins; Neovascularization, Pathologic; Proteins; Ribonuclease, Pancreatic; RNA, Messenger; Stomach Neoplasms

Human angiogenin, a potent inducer of neovascularization, is secreted by HT-29 colon adenocarcinoma cells. microgram doses of a monoclonal antibody that neutralizes the in vitro and in vivo activities of angiogenin prevent or delay the appearance of s.c. HT-29 tumors in athymic mice in a statistically significant, dose-dependent manner. The antibody is not cytotoxic to tumor cells in vitro, which indicates that inhibition of tumor growth most likely occurs by neutralization of the activity of angiogenin in vivo and further implies a critical role for angiogenin in the early development of HT-29 tumors. The results suggest a therapeutically useful approach to the treatment of angiogenin-dependent malignancy.

Topics: Adenocarcinoma; Animals; Antibodies, Monoclonal; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Immunoglobulin G; Male; Mice; Mice, Nude; Proteins; Ribonuclease, Pancreatic; Specific Pathogen-Free Organisms; Tumor Cells, Cultured

The base cleavage specificity of angiogenin toward naturally occurring polyribonucleotides has been determined by using rapid RNA sequencing technology. With 5S RNAs from Saccharomyces cerevisiae and Escherichia coli, angiogenin cleaves phosphodiester bonds exclusively at cytidylic or uridylic residues, preferably when the pyrimidines are followed by adenine. However, not all of the existent pyrimidine bonds in the 5S RNAs are cleaved, likely owing to elements of structure in the substrate. Despite the high degree of sequence homology between angiogenin and ribonuclease A (RNase A), which includes all three catalytic as well as substrate binding residues, the cleavage patterns with natural RNAs are unique to each enzyme. Angiogenin significantly hydrolyzes certain bonds that are not appreciably attacked by RNase A and vice versa. The different cleavage specificities of angiogenin and RNase A may account for the fact that the former is angiogenic while the latter is not.

Topics: Adenocarcinoma; Base Sequence; Cell Line; Colonic Neoplasms; Escherichia coli; Humans; Molecular Sequence Data; Neoplasm Proteins; Nucleic Acid Conformation; Polyribonucleotides; Ribonuclease, Pancreatic; RNA, Ribosomal; RNA, Ribosomal, 5S; Saccharomyces cerevisiae; Substrate Specificity

The amino acid sequence and disulfide bond pairing of human tumor derived angiogenin, the first tumor angiogenesis factor to be isolated in pure form from human sources, have been determined by conventional sequencing techniques adapted and applied to nanomole and subnanomole levels of material. Angiogenin, obtained from conditioned media of a human colonic adenocarcinoma cell line, is a single-chain protein consisting of 123 amino acids with the following sequences: less than Glu1-Asp-Asn-Ser-Arg-Tyr-Thr-His- Phe-Leu-Thr-Gln-His-Tyr-Asp15-Ala-Lys-Pro-Gln-Gly-Arg-Asp-Asp- Arg-Tyr-Cys-Glu-Ser-Ile-Met30- Arg-Arg-Arg-Gly-Leu-Thr-Ser-Pro-Cys-Lys-Asp-Ile-Asn-Thr- Phe45-Ile-His-Gly-Asn-Lys-Arg-Ser -Ile-Lys-Ala-Ile-Cys-Glu-Asn-Lys60-Asn-Gly-Asn-Pro-His-Arg-Glu-Asn -Leu-Arg-Ile -Ser-Lys-Ser-Ser75 -Phe-Gln-Val-Thr-Thr-Cys-Lys-Leu-His-Gly-Gly-Ser-Pro-Trp-Pro90-Pro -Cys-Gln-Tyr -Arg-Ala-Thr-Ala -Gly-Phe-Arg-Asn-Val-Val-Val105-Ala-Cys-Glu-Asn-Gly-Leu-Pro-Val- His-Leu-Asp-Gln-Ser-Ile-Phe120-Arg-Arg-Pro123-OH. Three disulfide bonds link the half-cystinyl residues 26-81, 39-92, and 57-107. The sequence is homologous to that of the pancreatic ribonucleases with 35% identity and many of the remaining residues conservatively replaced. Similarities are especially apparent around the major active-site residues His-12, Lys-41, and His-119 of ribonuclease which are conserved as are three of the four disulfide bonds.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenocarcinoma; Amino Acid Sequence; Angiogenesis Inducing Agents; Animals; Cell Line; Colonic Neoplasms; Cyanogen Bromide; Growth Substances; Horses; Humans; Hydroxylamine; Hydroxylamines; Indicators and Reagents; Neoplasm Proteins; Peptide Fragments; Pyroglutamyl-Peptidase I; Ribonuclease, Pancreatic; Species Specificity; Trypsin

The first human tumor derived protein with in vivo angiogenic activity to be obtained in pure form has been isolated from serum-free supernatants of an established human adenocarcinoma cell line (HT-29) and named angiogenin. It was purified by cation-exchange and reversed-phase high-performance liquid chromatography; the yield was approximately 0.5 microgram/L of medium. Biological activity of angiogenin was monitored throughout purification by using the chick embryo chorioallantoic membrane assay. Statistical evaluation demonstrates that it displays activity in this system with as little as 35 fmol per egg. Moreover, only 3.5 pmol is required to induce extensive blood vessel growth in the rabbit cornea. The amino acid composition of this basic (isoelectric point greater than 9.5), single-chain protein of molecular weight approximately 14 400 has been determined. The amino terminus is blocked, and the carboxyl-terminal residue is proline.

Topics: Adenocarcinoma; Allantois; Amino Acid Sequence; Amino Acids; Angiogenesis Inducing Agents; Animals; Biological Assay; Cell Line; Chick Embryo; Chorion; Colonic Neoplasms; Culture Media; Growth Substances; Humans; Molecular Weight; Neoplasm Proteins; Ribonuclease, Pancreatic