Cell cycle inhibition by the anti-angiogenic agent TNP-470 is mediated by p53 and p21WAF1/CIP1

Angiogenesis has been demonstrated to be essential for tumor growth and metastasis, and inhibition of angiogenesis is emerging as a promising strategy for treating cancer. Among the most potent inhibitors of angiogenesis is the fumagillin family of natural products. An analog of fumagillin, known as TNP-470 or AGM-1470, has been undergoing clinical trials for treating a variety of cancers. TNP-470 has been shown to block endothelial cell cycle progression in the late G(1) phase. Although the direct molecular target for TNP-470 has been identified as the type 2 methionine aminopeptidase (MetAP2), how inhibition of this enzyme leads to cell cycle arrest has remained unclear. We report that treatment of endothelial and other drug-sensitive cell types leads to the activation of the p53 pathway, causing an accumulation of the G(1) cyclin-dependent kinase inhibitor p21(WAF1/CIP1). The requirement of p53 and p21(WAF1/CIP1) for the cell cycle inhibition by TNP-470 is underscored by the observation that cells deficient in p53 and p21(WAF1/CIP1) are resistant to TNP-470. These results shed significant light on the mechanism of cell cycle inhibition by TNP-470 and suggest an alternative method of activating p53 in endothelial cells to halt angiogenesis and tumor progression.     

Growth inhibition of liver metastases by the anti-angiogenic drug TNP-470

OBJECTIVE: This study was undertaken in order to assess the efficacy of a potent angiogenesis inhibitor, TNP-470, on tumor growth in a syngeneic rodent model of liver metastases from colorectal cancer. BACKGROUND: New blood vessel formation is a prerequisite for primary and metastatic tumor growth. TNP-470, a synthetic derivative of fumagillin when subcutaneously transplanted into nude mice, inhibits endothelial cell proliferation and migration, as well as the growth of various human cancers. However, the antitumor effect of this drug has not been studied in models reproducing a natural metastatic environment. Since the liver provides an extensive vascular bed for secondary tumor growth, an anti-angiogenic strategy may therefore be less efficient for treating hepatic metastases than primary tumors. METHODS: 10(7) DHD K12 colon carcinoma cells were injected intrasplenically into syngeneic BD IX rats to produce diffuse liver metastases. TNP-470 (30 mg/kg/day) was administered on alternate days starting 4 days after tumor implantation. The animals were sacrificed after 4 weeks and their livers were processed for histologic examination. In both the treatment and control groups (n=7), tumor volume was determined using a computerized analytical system, and tumor microvessel density was measured by immunostaining with anti-von Willebrand Factor monoclonal antibody. RESULTS: In vitro, TNP-470 demonstrated a direct toxicity towards the DHD K12 cell line with an IC50 of 0.1 microg/ml. Metastases were present in all animals from both groups. Liver weight (15.2 g vs 11.7 g, p=0.01), and tumor volume (1218 mm3 vs 406 mm3, p=0.03) were significantly reduced in the TNP-470 group compared to the control group. Tumor microvessel density was not statistically different between the two groups (67 vs 63 microvessels/x200 field, p=0.41). CONCLUSION: TNP-470 inhibits the growth of liver metastases in a syngeneic rat model of colorectal cancer. The mechanism responsible for this effect remains unclear, but may involve a combination of anti-angiogenic and direct cytotoxic effects.     

Angiogenesis Inhibition by Angiostatin, Endostatin and TNP-470 Prevents Cyclophosphamide Induced Cystitis

Angiogenesis, the induction of vessel growth is involved in numerous physiological and pathological processes. While the anti-tumor effect of angiogenesis inhibitors has been extensively investigated in malignant tumors, there is very little information on the effect of angiogenesis inhibitors on inflammation induced angiogenesis. In this report, we utilized a murine model of acute chemically induced cystitis to investigate the ability of three different angiogenesis inhibitors, angiostatin, endostatin and TNP-470, to inhibit the angiogenesis stimulated by this injury. We demonstrate herein, that prophylactic application of the angiogenesis inhibitors led to a significant reduction of each of the inflammatory parameters that were measured. We conclude that anti-angiogenic therapy with angiostatin, endostatin and TNP-470 inhibits inflammation associated angiogenesis induced in this model. We also propose that anti-angiogenic agents may serve as a valuable addition to a standard cyclophosphamid chemotherapy regimen to help reduce the chemotherapy-related side effects while potentially adding an anti-tumor effect.     

Augmented antitumour effects of combination therapy with TNP-470 and chemoimmunotherapy in mice

PURPOSE: To investigate antitumour efficacy of the combination of the antiangiogenic agent TNP-470 combined with chemoimmunotherapy in different tumour models in mice MATERIALS: B6D2F1 mice and BALB/c mice were inoculated in the footpad of the right hind limb with B16F10 melanoma cells or colon adenocarcinoma cells C-26, respectively. Subsequently, they received therapy consisting of TNP-470 and/or IL-12 and tumour growth was observed. In the melanoma model this therapy regimen was combined with cisplatin in a subtherapeutic dose. The antiangiogenic action of the tested agents was evaluated using tumour-induced angiogenesis assay in vivo. In order to analyse interactions between TNP-470 (or cisplatin) and IFN-gamma on tumour cells in vitro, the following methods were used: MTT assay, Western blot analysis, and flow cytometry analysis. RESULTS: Administration of the combined therapy with TNP-470 and IL-12 resulted in augmented antitumour activity in colon-26 and B16F10 melanoma models. Addition of cisplatin further enhanced efficacy of this combined therapy in the melanoma model. We showed that antitumour activity of this combined therapy is mediated by multiple mechanisms: not only is enhancement of the antiangiogenic activity mediated by TNP-470 and IL-12 but also by the synergistic cytostatic/cytotoxic action of IL-12-induced IFN-gamma and TNP-470 or cisplatin on tumour cells. The experiments revealed that TNP-470 together with IFN-gamma leads to the increased expression of p21 protein in cancer cells, which in turn may contribute to their cytostatic/cytotoxic action in vitro. CONCLUSION: Our experiments show a successful TNP-470-based combination therapy and suggest that the enhancement of the antitumour activity could be explained by a concomitant effect on both endothelial and tumour cell compartments.     

TNP-470 fails to block the onset of angiogenesis and early tumor establishment in an intravital minimal disease model

BACKGROUND AND AIMS: The angiogenesis inhibitor TNP-470 (AGM-1470) has shown encouraging results in animal models of established tumors. However, results of recent clinical trials using TNP-470 have been disappointing. Since little is known about the effects of TNP-470 at the minimal disease stage, we analyzed the effects of TNP-470 on the early stages of tumor establishment. METHODS: Twenty thousand green fluorescent protein (GFP)-transfected murine CT-26 (colonic carcinoma) or Panc-02-H0 (pancreatic adenocarcinoma) cells were inoculated in dorsal skin-fold chambers in BALB/c or C57BL6 mice. Tumor area and microvessel density (MVD) were quantified by intravital microscopy (IVM). Body weight was also monitored. Effects were compared with those in a conventional model involving subcutaneous (s.c.) inoculation of 10(6) tumor cells, followed by measurement of tumor volume, endogenous plasma VEGF/endostatin (ELISA) and proliferation/apoptosis/microvessel density (Ki-67/TUNEL/CD-34). TNP-470 was injected s.c. over the 10-day experimental period (30 mg/kg every 2 days [n=6] to 100 mg/kg/day [n=5 dorsal skin-fold chamber model, n=4 s.c. tumor model]). RESULTS: At 30 mg/kg/every second day neither CT-26 nor PANC-02-H0 tumors were inhibited in neither of the two models. TNP-470 dosage was escalated in CT-26-bearing animals until an antiangiogenic effect could be observed. In the IVM model, only TNP-470 100 mg/kg/day reduced MVD (P=0.006), but failed to block the onset of angiogenesis and tumor area increase. Body weight decreased by 25% (P<0.05). In the subcutaneous tumor model, tumor growth was reduced (P=0.045) but not blocked, while vascular endothelial growth factor (VEGF)/endostatin synthesis and Ki67/TUNEL/CD-34 were not significantly affected. CONCLUSION: While capable of reducing tumor growth in a conventional model, treatment with TNP-470 does not block the onset of angiogenesis and tumor establishment in a model of minimal disease. When used as a single agent TNP-470 does not control minimal tumor disease in experimental colonic carcinoma.     

Inhibitory effect of the angiogenesis inhibitor TNP-470 on tumor growth and metastasis in nude mice bearing human hepatocellular carcinoma

The antitumor and anti-metastatic effects of a potent angiogenesis inhibitor,O-(chloroacetyl-carbamoyl)fumagillol (TNP-470), was investigated in a highly metastatic model of human hepatocellular carcinoma—LCI-D20. Small pieces of LCI-D20 tumor tissue were implanted subcutaneously into the right axillary region of 24 nude mice; the mice were then randomized into two groups. To one group, TNP-470 30 mg/kg was given as a subcutaneous injection every other day from day 1 to day 15 and the mice were sacrificed on day 26. An antitumor effect of TNP-470 was clearly demonstrated by tumor weight (0.97±0.34 g compared to 2.04±0.34 g,P<0.001) and -Fetoprotein value (93±59 g/L compared to 769±282 g/L,P<0.001). There was also an anti-metastatic effect of TNP-470. Lung metastases developed in only 1 of 12 mice in the treated group, while they developed in 6 of mice of the control group. No severe side-effect of TNP-470 was found in this study. In vitro study revealed that the purified hepatoma cells were insensitive to TNP-470 (the 50% inhibitory concentration was 43 g/ml). These results suggest that the angiogenesis inhibitor TNP-470 has both strong antitumor and anti-metastatic effects on a human hepatocellular carcinoma model in nude mice.Abbreviations TNP-470 O-(chloroacetyl-carbamoyl) Fumagillol - MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide This work was partly supported by the CHina Medical Board of New York, grant 93-583, and a Leading Speciality grant of Shanghai Health Bureau     

Anti-tumor effect of angiogenesis inhibitor TNP-470 and 5-FU combined therapy on human gastric cancer xenograft

BACKGROUND/AIMS: TNP-470, an angiogenesis inhibitor, has already been used in combination with chemotherapy to enhance its antitumor activity. The mechanism of enhanced antitumor activity in combination therapy has not been clarified, however, and few studies have described the combined effect of TNP-470 and 5-fluorouracil (5-FU) on gastric cancer. The present study was conducted to investigate the effect of TNP-470 + 5-FU on gastric cancer cell line MKN-45 in vivo and in vitro. METHODOLOGY: MKN-45 cells were subcutaneously injected into mice that were divided into 4 groups: a control group, a 5-FU treated group, a TNP-470 treated group, and a 5-FU + TNP-470 treated group. After the inoculation, the volume of subcutaneous tumors was measured. Blood and lymphatic vessels were also analyzed for the assessment of lymphangiogenesis. RESULTS: Compared with 5-FU or TNP-470 alone, the combined effect of TNP-470 and 5-FU significantly inhibited and suppressed tumor growth in a synergistic fashion. The combined therapy significantly suppressed both angiogenesis and lymphagenesis. CONCLUSIONS: The study suggests that the combined therapy provides an enhanced antitumor effect on human gastric cancer. The enhanced antitumor activity is explained mainly by the stronger inhibition of angiogenesis.     

Antitumor activity of the angiogenesis inhibitor TNP-470 on murine lymphoma/leukemia cells in vivo and in vitro

OBJECTIVE: The aim of this study was to evaluate the effects of an angiogenesis inhibitor in a non-immunocompromised setting in which transplanted tumor cells home and expand in a manner mimicking the original tumor in the donor. We used a novel animal model for T-cell lymphoma/leukemia (TLL) to test the antitumor effect of TNP-470, a well-established angiogenesis inhibitor. MATERIALS AND METHODS: Cells from spontaneously arisen TLL tumors were transferred to syngenic recipients. The mice were treated with TNP-470 (30 mg/kg) or vehicle every other day for 2 weeks. Mice were sacrificed on day 15 after transfer, and body and organ weights were measured. Cell cycle and morphologic analysis was performed on cells and/or sections from selected organs. The cytotoxic effect of TNP-470 was assayed in vitro using the TLL-M and HL-60 cell lines. RESULTS: TNP-470 treatment significantly reduced total tumor load and tumor mass in specific organs infiltrated with lymphoma/leukemia. This was associated with an increased apoptosis in these organs. We also observed side effects of TNP-470 not previously reported, such as diminished extramedullary erythropoiesis and disrupted liver morphology. In vitro TLL-M cells were resistant to cytotoxic effects of moderate doses of TNP-470. CONCLUSIONS: TNP-470 treatment has a beneficial effect on tumor load in the TLL transfer model, most likely caused by the antiangiogenic effect of TNP-470. This is supported by the observation of increased apoptosis in infiltrated organs. The TLL transfer model is well suited for further studies of combinations with TNP-470 or other angiogenesis inhibitors and cytotoxic drugs.     

The antiangiogenic agent TNP-470 requires p53 and p21CIP/WAF for endothelial cell growth arrest

Targeting the endothelial cell cycle as an antiangiogenic strategy has been difficult given the ubiquitous expression of critical cell cycle regulators. Here, we show that the antiangiogenic drug TNP-470 displays striking cell-type specificity insofar as it induces the expression of p21(CIP/WAF), a cyclin-dependent kinase inhibitor, in endothelial cells but not in embryonic or adult fibroblasts. Moreover, primary endothelial cells isolated from p53(-/-) and p21(CIP/WAF-/-) mice are resistant to the cytostatic activity of TNP-470. We also demonstrate that p21(CIP/WAF-/-) mice are resistant to the antiangiogenic activity of TNP-470 in the basic fibroblast growth factor corneal micropocket angiogenesis assay. We conclude that TNP-470 induces p53 activation through a unique mechanism in endothelial cells leading to p21(CIP/WAF) expression and subsequent growth arrest.     

TNP-470 and recombinant human interferon-alpha2a inhibit angiogenesis synergistically

The hypothesis that the combination of two known antiangiogenic agents TNP-470 and interferon (IFN)-alpha exerts synergistic effects has been investigated in vitro and in vivo. In vitro, TNP-470 and recombinant human IFN-alpha2a (rhIFN-alpha2a) resulted in a dose-dependent inhibition of proliferation of human umbilical vein endothelial cells (HUVECs) and EA.hy926 endothelial cells. Compared with the two agents used singly at their lowest or ineffective doses, combined treatment with the same doses inhibited more intensely in the absence of cytotoxicity and displayed similar behaviour on cell chemotaxis and capillary morphogenesis on Matrigel. However, the secretion of matrix metalloproteinase 2 (MMP-2) and MMP-9 was not influenced by the two agents, either alone or in combination, even when they were applied at their lowest efficacious doses or at higher cytotoxic doses. Experiments in vivo with the chick embryo chorioallantoic membrane (CAM)-sponge assay revealed the same dose-dependent inhibition and synergy. As the basic fibroblast growth factor (bFGF)-induced angiogenesis in the CAM-sponge model was strongly inhibited by the combined treatment, TNP-470 and rhIFN-alpha2a would appear to exert antiangiogenesis synergistically, perhaps by interfering with the bFGF-mediated pathway.     

Suppression of arthritis and protection from bone destruction by treatment with TNP-470/AGM-1470 in a transgenic mouse model of rheumatoid arthritis

OBJECTIVE: We assessed the clinical and histologic features of angiogenesis inhibition in a transgenic mouse model of arthritis that closely resembles rheumatoid arthritis (RA) in humans. METHODS: KRN/NOD mice, which spontaneously develop arthritis, were treated with TNP-470, an angiogenesis inhibitor. Disease was monitored by use of clinical indices and histologic examinations; circulating blood levels of vascular endothelial growth factor were determined by enzyme-linked immunosorbent assay. RESULTS: In the preventive protocol, with TNP-470 administration at a dosage of 60 mg/kg of body weight, the onset of arthritis was delayed and its clinical intensity was rather mild; 100% of placebo-treated transgenic mice developed arthritis that led to severe articular destruction. At a dosage of 90 mg/kg of TNP-470, the appearance of clinical signs was delayed for a longer period of time and disease was almost abolished. The therapeutic regimen alleviated clinical signs only when given during the very early stage of disease. Reductions in cartilage and bone destruction by TNP-470 treatment were observed histologically, a feature that was still evident at 30 and 80 days after injections were withdrawn. CONCLUSION: Our demonstration that in vivo administration of an angiogenesis inhibitor suppresses arthritis and protects from bone destruction provides new insight into the pathogenesis of the disease and opens new possibilities in the treatment of RA in humans.     

Anti-angiogenic therapy in pediatric brain tumors: An effective strategy?

Brain tumors are still the leading cause of cancer morbidity and mortality among children, despite different therapeutic options including neurosurgery, chemotherapy and radiation. As angiogenesis is highly crucial in brain tumor growth and progression, numerous clinical trials evaluating diverse anti-angiogenic agents have been described. In the present review, we aimed to answer the question if anti-angiogenic therapy is an effective strategy in the treatment of children with brain tumors. Although some encouraging results have been published of anti-angiogenic therapy targeting vascular endothelial growth factor (VEGF)/VEGF receptor signaling or epidermal growth factor receptor (EGFR), still more insight is warranted to be highly conclusive about the efficacy of anti-angiogenic therapy with currently potential upcoming anti-angiogenic agents in pediatric brain tumors. However, given the need for new therapeutic strategies, multi targeted therapy with anti-angiogenic agents anticipating on possible tumor escape mechanisms could be effective in the future treatment of pediatric brain tumors.     

Effects of TNP-470 on proliferation and apoptosis in human colon cancer xenografts in nude mice

AIM: To study the effect of TNP-470 on cell growth, proliferation and apoptosis in human colon cancer xenografts in nude mice. METHODS: Human colon cancer xenografts were transplanted into 20 nude mice. Mice were randomly divided into two groups. TNP-470 treated group received TNP-470(30 mg/kg, s.c) every other day and the control group received a sham injection of same volume saline solution. They were sacrificed after 4 weeks and their tumors were processed for histological examination. The expression of proliferating cell nuclear antigen (PCNA) in tumors was detected using immunohistochemical method with image analysis, and apoptosis in tumor cells was measured by TdT-mediated biotinyated-dUTP nick end labeling (TUNEL) staining. RESULTS: Comparing with controls, tumor growth was significantly inhibited in TNP-470 treated group, the inhibitory rate being 54.4 %. Expression of PCNA in tumors of TNP-470 treated group (PI 54.32+/-11.47) was significantly lower than that of control group (PI 88.54+/-12.36), P<0.01. Apoptosis index (AI) of TNP-470 treated group (18.95+/-1.71) was significantly higher than that of control group (7.26+/-1.44), P<0.001, typical morphological change of apoptosis in tumor cells was observed in TNP-470 treated group. CONCLUSION: Besides the anti-angiogenic effects, TNP-470 can inhibit tumor growth by inhibiting the proliferation and inducing apoptosis of tumor cells.     

Complete remission of Bomirski Ab amelanotic melanoma in hamsters treated with the angiogenesis inhibitor TNP-470

The growth of solid tumors and their metastasis is dependent on the development of new blood vessels (angiogenesis). In our previous studies it was found that angiogenesis inhibitor TNP-470 acting systematically can decrease the rate of growth of transplantable Bomirski Abmelanoma in hamsters. In this study we applied TNP-470 (30 mg/kg) peritumorally from the day when tumor was palpable over 10 days, once daily. Animals were killed 6 months later and examination by autopsy and histological preparations showed the complete remission of transplanted tumor and the lack of metastasis. Thus, Ab melanoma can be effectively cured with TNP-470 angiogenesis inhibitor when the substance is applied locally.     

Tumor angiogenesis

Angiogenesis have shown a major role in tumor growth and metastasis formation. For tumor growth beyond the size 1-2 mm3, angiogenesis must be started to form vascular supply of tumor cells. Angiogenesis is a complex process, involving degradation of the basement membrane of preexisting vessel, proliferation of endothelial cells towards the angiogenetic stimulus, maturation of endothelial cells with formation of luminized capillary, and finally formation of a functional vessel, surrounded by basement membrane and pericytes. Angiogenesis is regulated by numerous angiogenic and anti-angiogenic factors. Hypoxia is a significant stimulus for angiogenesis. For many cancers the extent of vascularisation is a negative prognostic indicator signifying aggressive disease and increased potential for metastasis.     

TNP-470对肺腺癌细胞增殖和凋亡的影响

目的 探讨TNP－470对肺腺癌细胞增殖和凋亡的影响及其作用机制。方法 以不同浓度的TNP－470信息处理地培养的肺腺癌AGZY－82A细胞株,以免疫组化S－P法检测肺腺癌细胞增殖核抗原（PCNA）、p53、bcl-2、血管内皮生长因子（VEGF）和VEGF受体Flk-1的表达。结果 随着TNP－470浓度的增加,肺腺癌细胞VEGF、Flk-1、PCNA的表达减少,p53、bcl-2的表达逐渐增加;当TNP－470为10^7μg/L时,细胞增殖几乎停止,随着TNP－470（10^4μg/L）作用时间的延长,肺腺癌细胞VEGF、Flk-1、PCNA的表达逐渐减少,而p53、bcl-2的表达逐渐增加。结论 TNP－470通过使肺腺癌细胞自分泌VEGF减少,Flk表达降低,从而抑制肺腺癌细胞增殖,促进其凋亡。     

The anti-angiogenic agent fumagillin covalently binds and inhibits the methionine aminopeptidase, MetAP-2

The inhibition of new blood vessel formation (angiogenesis) is an effective means of limiting both the size and metastasis of solid tumors. The leading anti-angiogenic compound, TNP-470, has proven to be effective in in vitro and in animal model studies, and is currently being tested in phase III antitumor clinical trials. Despite many detailed pharmacological studies, little is known of the molecular mode of action of TNP-470. Using a derivative of the TNP-470 parent compound, the fungal metabolite, fumagillin, we have purified a mammalian protein that is selectively and covalently bound by this natural product. This fumagillin binding protein was found to be a metalloprotease, methionine aminopeptidase (MetAP-2), that is highly conserved between human and Saccharomyces cerevisiae. In the absence of MetAP-1, a distantly related methionine aminopeptidase, MetAP-2 function is essential for vegetative growth in yeast. We demonstrate that fumagillin selectively inhibits the S. cerevisiae MetAP-2 protein in vivo. The binding is highly specific as judged by the failure of fumagillin to inhibit MetAP-1 in vivo. Hence, these results identify MetAP-2 as an important target of study in the analysis of the potent biological activities of fumagillin.     

血管生成抑制剂TNP-47O与细胞毒药物Gemcitabine的抗胰腺癌生长和转移作用的比较研究

目的　探讨血管生成抑制剂 (TNP- 4 70 )和细胞毒药物 (Gemcitabine)对胰腺癌裸鼠原位移植模型 (SOI)生长、转移的抑制作用及其作用机制。方法　把胰腺癌细胞株 SW1990皮下种植生长的癌组织移植于裸鼠胰腺尾部 ,制备胰腺癌 SOI模型 ;2 4只 SOI模型随机分为 TNP组 (TNP- 4 70 30 m g/ kg,皮下注射 ,隔日一次 ,疗程 8周 )、GEM组 (Gemcitabine 10 0 mg/ kg,腹腔内注射 ,术后第 0、3、6、9天给药 )和对照组 ,术后第 10周处死裸鼠。结果　 Gemcitabine侧重于抗胰腺癌生长 ,TNP- 4 70则侧重抑制胰腺癌转移 ,两者均无显著的预后改善作用 ;TNP组的微血管密度 (MVD)显著低于 GEM组和对照组 ,GEM组的肿瘤增殖指数 (PI)显著低于 TNP组和对照组 (均 P<0 .0 5 )。结论　血管生成抑制剂和细胞毒药物在抗肿瘤生长和转移的侧重点和作用机制方面均存在显著差异。     

Endogenous stimulators and inhibitors of angiogenesis in gastrointestinal cancers: basic science to clinical application

Progression of cancer is dependent on acquisition of vascular networks within the tumor. Tumor angiogenesis is dependent on up-regulation of angiogenesis stimulators to overcome the endogenous anti-angiogenic barrier. Such disruption of angiogenesis balance to favor neovascularization is a key step for progression of tumor growth and metastasis. In this regard, the vascular basement membrane and the extracellular matrix have been found to be rich sources of angiogenesis stimulators and inhibitors that become bioavailable on proteolysis of the matrix by tumor microenvironment-related enzymes. In this review the subgroup of endogenous angiogenesis stimulators and inhibitors is discussed, and their mechanism of action during tumor angiogenesis is evaluated. The role in regulating tumor growth and the possibility of using them as prognostic markers for human gastrointestinal cancers is discussed. Furthermore, we specifically address the role of vascular endothelial growth factor in human gastrointestinal cancers and discuss the development and use of bevacizumab (Avastin; anti-vascular endothelial growth factor antibody [Genentech, CA]) in the treatment of colorectal and other gastrointestinal cancers.     

Angiogenesis inhibitor, TNP-470, suppresses growth of peritoneal disseminating foci

BACKGROUND/AIMS: Angiogenesis is critical not only for growth of primary tumors but also for cells established at distant organs. We investigated the effects of angiogenesis inhibitor, TNP-470, on the establishment and growth of intraperitoneally inoculated human gastric cancer cell line, MKN-45, and survival of nude mice with this tumor. METHODOLOGY: Human gastric cancer cell line, MKN-45, were injected into the peritoneal cavity of an ICR nude mouse and a model of peritoneal dissemination was developed. TNP-470 was injected subcutaneously every other day from day 1 until sacrifice or death. The effects of TNP-470 on MKN-45 cells were also examined in vitro. RESULTS: Although the number of disseminated foci was not significantly different, the maximum size was significantly smaller in a TNP-treated group than those of a control. Survival time was significantly longer in a TNP-treated group. TNP-470 demonstrated no growth inhibition of MKN45 cells in vitro. CONCLUSIONS: Those results suggested that anti-angiogenic agent, TNP-470, might be effective in treating peritoneal dissemination of gastric cancer by inhibiting growth of the seeded tumor cells on the peritoneum.