Human endostatin inhibits growth of human non-small-cell lung cancer in a murine xenotransplant model

CD44 targeting nanodrug based on chondroitin sulfate for melanoma therapy by inducing mitochondrial apoptosis pathways

Neovascularization is crucial to the occurrence and progression of tumors, and the development of antiangiogenic drugs has essential theoretical value and clinical significance. However, antiangiogenesis therapy alone cannot meet the needs of tumor therapy. Meanwhile, polysaccharides are ideal drug carriers with promising applications in drug modification and delivery. In this research, we developed a novel redox and acid sensitive nanodrug (CDDP-CS-Cys-EA, CCEA) composed of chondroitin sulfate (CS), antiangiogenic peptide (endostatin2-alft1, EA) and chemotherapeutic drug (cisplatin, CDDP). CCEA exhibited redox and acid responsiveness, better blood hemocompatibility (hemolysis rate < 5 %), the ability to target tumors (CD44-mediated endocytosis), and strong antiangiogenesis and antitumor characteristics in vitro. Moreover, CCEA showed excellent antitumor activity and low toxicity in B16 xenograft mice. It also has been confirmed that CCEA induced tumor cell apoptosis through promoting the expression of Bax, suppressing the expression of Bcl-2, decreasing mitochondrial membrane potential, releasing cytochrome C (Cyto C), and enhancing the activities of Caspase 9 and Caspase 3. The results of this paper provided a theoretical basis and insight for the development of antitumor drugs.

Real-world outcomes of various regimens of recombinant human endostatin combined with chemotherapy in non-driver gene mutation advanced non-small cell lung cancer

AIMS

This real-world study is conducted to evaluate the efficacy and safety of recombinant human endostatin (rh-endostatin) combined with chemotherapy as first-line treatment for non-driver genes mutation non-small cell lung cancer (NSCLC) patients, and establish evidence-based optimal regimen for rh-endostatin.

PATIENTS AND METHODS

Using propensity score matching (cut-off: 0.01), 88 patients were eligible for our study, 34 of which received platinum-based chemotherapy alone (chemotherapy group), 54 patients received platinum-based chemotherapy plus rh-endostatin (rh-endostatin group). Among those 54 patients in the rh-endostatin group, 27 patients received rh-endostatin administered at 7.5 mg/m² from day 1 to day 14 (rh-endostatin 14d group), and the other 27 patients were administered at 15 mg/m² from day 1 to day 7 (rh-endostatin 7d group). The primary endpoint was progression-free survival (PFS) and secondary endpoints were overall survival (OS), overall response rate (ORR), disease control rate (DCR), and safety.

RESULTS

There were no differences in clinic characteristics among 3 groups. Compared with chemotherapy group, rh-endostatin group improved PFS and OS significantly. The median PFS was 6 months vs 4.5 months (P = 0.047), and median OS was 20 months vs 10 months (P < 0.001). The ORR was 33.3% vs 20.6% (P = 0.197) and DCR was 83.3% vs 64.7% (P = 0.046) in the rh-endostatin group and chemotherapy group, respectively. The comparisons between the rh-endostatin 7d and 14d groups revealed a significant improvement in PFS for the rh-endostatin 7d group (P = 0.044), but no significant differences in OS (P = 0.111), ORR (P = 0.074), or DCR (P = 0.234). The incidences of grade 3 and 4 adverse events were similar among 3 groups.

CONCLUSION

Chemotherapy combined with rh-endostatin was more effective than chemotherapy alone for non-driver gene mutation NSCLC patients. The administration of rh-endostatin for 7 days at 15 mg/m² was non-inferior to 14 days at 7.5 mg/m² in prolonging patients' PFS. Further evaluation should be conducted before its application in clinical work.

A phase II study of Endostatin in combination with paclitaxel, carboplatin, and radiotherapy in patients with unresectable locally advanced non-small cell lung cancer

Background

Endostatin inhibits the pro-angiogenic action of basic fibroblast growth factor and vascular endothelial growth factor in different human cancers. This study assessed the efficacy of endostatin combined with concurrent chemoradiotherapy of non-small cell lung cancer (NSCLC).

Methods

Nineteen patients with unresectable stage III NSCLC, Eastern Cooperative Oncology Group (ECOG) performance status 0-l, and adequate organ function were treated with 60–66 Gy thoracic radiation therapy over 30–33 fractions concurrent with weekly 7.5 mg/m² endostatin for 14 days, 50 mg/m² paclitaxel, and 2 mg/mL/min carboplatin over 30 min. Patients were then treated with 7.5 mg/m² endostatin for 14 days, 150 mg/m² paclitaxel, and 5 mg/mL/min carboplatin every 3 weeks for 2 cycles as the consolidation treatment. The objective response rate was recorded according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and the toxicity was evaluated using the National Cancer Institute (NCI) Common Toxicity Criteria.

Results

Six patients were unable to complete the consolidation treatment (4 pulmonary toxicity, 1 tracheoesophageal fistulae, and 1 progressive disease). Seventeen patients were included for data analysis. Specifically, one (5.9 %) patient had a complete response and 12 (70.6 %) had a partial response, whereas two patients had stable disease and the other two had disease progression. The overall response rate was 76 % (95 % confidence interval [CI], 51 %–97 %). The median progression-free survival was 10 months (95 % CI, 7.6–12.3 months), and the median overall survival was 14 months (95 % CI, 10.7–17.2 months). Early 10 patients who completed the treatment regimen showed that four patients experienced grade III pulmonary toxicity a few months after chemoradiotherapy, leading to the early closure of the trial according to the study design.

Conclusions

The reslult of concurrent endostatin treatment with chemoradiotherapy in locally advanced unresectable NSCLC did not meet the goal per study design with unacceptable toxicity. The real impact of endostatin as the first-line treatment combined with chemoradiotherapy on the survival of NSCLC patients remains to be determined. (NCT 01158144).

Bioluminescent orthotopic mouse models of human localized non-small cell lung cancer: feasibility and identification of circulating tumour cells

Background

Preclinical models of non-small cell lung cancer (NSCLC) require better clinical relevance to study disease mechanisms and innovative therapeutics. We sought to compare and refine bioluminescent orthotopic mouse models of human localized NSCLC.

Methods

Athymic nude mice underwent subcutaneous injection (group 1-SC, n = 15, control), percutaneous orthotopic injection (group 2-POI, n = 30), surgical orthotopic implantation of subcutaneously grown tumours (group 3-SOI, n = 25), or transpleural orthotopic injection (group 4-TOI, n = 30) of A549-luciferase cells. Bioluminescent in vivo imaging was then performed weekly. Circulating tumour cells (CTCs) were searched using Cellsearch® system in SC and TOI models.

Results

Group 2-POI was associated with unexpected direct pleural spreading of the cellular solution in 53% of the cases, forbidding further evaluation of any localized lung tumour. Group 3-SOI was characterized by high perioperative mortality, initially localized lung tumours, and local evolution. Group 4-TOI was associated with low perioperative mortality, initially localized lung tumours, loco regional extension, and distant metastasis. CTCs were detected in 83% of nude mice bearing subcutaneous or orthotopic NSCLC tumours.

Conclusions

Transpleural orthotopic injection of A549-luc cells in nude mouse lung induces localized tumour, followed by lymphatic extension and specific mortality, and allowed the first time identification of CTCs in a NSCLC mice model.

The synergistic effect of recombinant human endostatin (YH-16) combined with oxaliplatin on human colorectal carcinoma

This study was designed to investigate the effect of recombinant human endostatin (YH-16) combined with oxaliplatin (L-OHP) on the growth of orthotopically-implanted human colorectal carcinoma in nude mice. Tumour volumes and weights were measured after therapy. Tumour cell morphology was observed by light and electron microscopy. Apoptosis was detected using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling (TUNEL) assay, and vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) were determined by immunohistochemical staining. Tumour volumes in all treatment groups were significantly reduced compared with controls. YH-16 and L-OHP either alone or in combination caused tumour cell apoptosis, except in the YH-16 low-dose group. MVD was strongly inhibited in the treatment groups compared with the controls, although only YH-16 combined with L-OHP or L-OHP alone decreased VEGF expression. No obvious change in side-effects occurred. In conclusion, YH-16 combined with L-OHP inhibited growth and induced apoptosis in orthotopically-transplanted human colorectal carcinoma in nude mice without increasing side-effects.

Impact of endostatin on bFGF-induced proliferation, migration, and matrix metalloproteinase-2 expression/secretion of bovine choroidal endothelial cells

PURPOSE

To investigate the potential role of endostatin, an endogenous angiogenesis inhibitor, in the prevention of choroidal angiogenesis-related disorders.

METHODS

Bovine choroidal endothelial cells (CEC) were cultured and treated with basic fibroblast growth factor (bFGF) alone or combined with endostatin at concentrations ranging from 0.1 to 10 microg/ml. The proliferation and migration of CECs were evaluated by using 3, (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and modified Boyden chamber assay, respectively. For evaluating expression and secretion of matrix metalloproteinase-2 (MMP-2), CEC-conditioned media were subjected to zymography and/or Western blot analysis, and the cells were used for semiquantitative reverse transcription polymerase chain reaction (RT-PCR) analysis.

RESULTS

Endostatin did not inhibit bFGF-induced or nonstimulated CEC proliferation (p > 0.05). The bFGF-induced migration was significantly inhibited by endostatin at concentrations of 1 and 10 microg/ml (p < 0.05). The bFGF-upregulated expression of mRNA in CECs and the secretion of MMP-2 protein of CECs were both suppressed by endostatin.

CONCLUSIONS

Inhibitory effect of endostatin on expression and secretion of MMP-2 and cell migration, but not on proliferation of CECs, could respond to its therapeutic action for choroidal neovascularization-dependent disorders.

Liposome transfected to plasmid-encoding endostatin gene combined with radiotherapy inhibits liver cancer growth in nude mice

AIM: To evaluate whether intratumoral injection of liposome-endostatin complexes could enhance the antitumor efficacy of radiation therapy in human liver carcinoma (BEL7402) model.

METHODS: Recombinant plasmid pcDNA3.End was transfected into human liver carcinoma cell line (BEL7402) with lipofectamine to produce conditioned medium. Then BEL7402 cells and human umbilical vein endothelial cells (HUVECs) were treated with the conditioned medium. Cell cycle and apoptosis were analyzed by flow cytometer and endothelial cell proliferation rates were determined by MTT assay. The antitumor efficacy of endostatin gene combined with ionizing radiation in mouse xenograft liver tumor was observed.

RESULTS: Endostatin significantly suppressed the S phase fraction and increased the apoptotic index in HUVECs. In contrast, endostatin treatment had no effect on BEL7402 cell apoptosis (2.1 ± 0.3% vs 8.9 ± 1.3%, t = 8.83, P = 0.009<0.01) or cell cycle distribution (17.2 ± 2.3% vs 9.8 ± 1.2%, t = 4.94, P = 0.016<0.05). The MTT assay showed that endostatin significantly inhibited the proliferation of HUVECs by 46.4%. The combination of local endostatin gene therapy with radiation therapy significantly inhibited the growth of human liver carcinoma BEL7402 xenografts, the inhibition rate of tumor size was 69.8% on d 28 compared to the untreated group. The tumor volume in the pcDNA3.End combined with radiation therapy group (249 ± 83 mm³) was significantly different from that in the untreated group (823 ± 148 mm³, t = 5.86, P = 0.009<0.01) or in the pcDNA3 group (717 ± 94 mm³, t = 6.46, P = 0.003<0.01). Endostatin or the radiation alone also inhibited the growth of liver tumor in vivo, but their inhibition effects were weaker than those of endostatin combined with radiation, the inhibition rates on d 28 were 44.7% and 40.1%, respectively.

CONCLUSION: Endostatin not only significantly suppresses tumor growth but also enhances the antitumor efficacy of radiation therapy in human carcinoma xenograft.

Angiogenesis in benign and malignant thyroid disease

CONTEXT

Angiogenesis has been recognized as an important process contributing to the pathophysiology of many benign and malignant diseases. It is not surprising, therefore, that this complex process is proving to be an important regulator of both benign and malignant disease processes in the thyroid gland. This paper will review the general principles of angiogenesis and lymphangiogenesis, as well as the importance of the balance between angiogenic stimulators and inhibitors in the normal thyroid gland. We will also review how this balance is disturbed in benign and malignant thyroid conditions. Finally, we will address the role manipulation of this process may play in the development of novel treatment strategies for diseases of the thyroid.

OBJECTIVE

To review the literature concerning the role of angiogenesis in the thyroid gland.

CONCLUSIONS

Angiogenesis is an important process which has been shown to be involved in the pathophysiology of benign and malignant diseases of the thyroid gland. Manipulation of this process holds great promise for the development of novel treatments for these disorders. As the mechanisms regulating angiogenesis in the thyroid become increasingly clear, researchers will come ever closer to turning this promise into clinical reality.

Antitumor activity of hydrophilic Paclitaxel copolymer prodrug using locoregional delivery in human orthotopic non-small cell lung cancer xenograft models

Paclitaxel (Taxol) has demonstrated clinical activity in non-small-cell lung cancer (NSCLC), but its use has not led to marked improvements in survival. This ineffectiveness can in part be attributed to inadequate delivery of effective drug levels to the lung via systemic administration and to drug resistance mechanisms. Locoregional drug administration and the use of drug copolymers are possible approaches to address these issues. In this study, we evaluated the activity of a poly(L-glutamic acid)-paclitaxel (PGA-TXL) formulation administered by intratracheal injection to mice bearing orthotopic human NSCLC tumors (H460, H358). H460 cells were found to be sensitive to paclitaxel and PGA-TXL in vitro, in a time- and concentration-dependent manner. In preliminary acute toxicity studies, PGA-TXL administered by intratracheal injection was found to be much less toxic than paclitaxel, as anticipated. Mice into which H460 cells had been implanted by intratracheal injection were given single-dose intratracheal treatments with paclitaxel (1.2 or 2.4 mg/kg) or with PGA-TXL (15 mg/kg, paclitaxel equivalents) 1 week later. When the mice were sacrificed at up to 65 days after tumor implantation, they were evaluated grossly for tumor at bronchial, neck, and lung sites. Control mice had tumors in 60% of all three sites, and all of the control mice had tumors in at least one site. The low- and high-dose Taxol groups had fewer incidences at these three sites (27-33%) and 60-80% of these mice had tumors in at least one site. The PGA-TXL mice displayed a low (13%) incidence at these sites, and only 40% had detectable tumors. In a subsequent survival study with the intratracheal H358 model, control mice had a mean life span of 95 days, whereas both the intratracheal Taxol (2.5 mg/kg, every 7th day for three doses) and the intratracheal PGA-TXL (20 mg/kg, paclitaxel equivalents, every 7th day for three doses) groups had improved survival (mean life spans: 133.5 and 136.5 days, respectively). In pilot studies intended to compare the feasibility of the development of paclitaxel aerosols suitable for clinical application, based either on Cremophor solutions or on PGA backbones, only the latter gave acceptable particle size distributions and flow rates. These results encourage the development and application of Cremophor-free copolymer formulations of paclitaxel for locoregional treatment (e.g., as aerosol) of endobronchial malignant diseases.

Angiogenesis inhibitors in the treatment of small cell and non-small cell lung cancer

Angiogenesis is believed to play a critical role in cancer; however, antiangiogenic therapy has not been demonstrated to improve the survival of patients who have lung cancer. In this article, the evidence that supports a role for angiogenesis in the pathogenesis of lung cancer, trials of antiangiogenic agents in lung cancer performed to date, and the lessons learned from these studies are discussed.

Overexpression of Collagen XVIII Is Associated with Poor Outcome and Elevated Levels of Circulating Serum Endostatin in Non–Small Cell Lung Cancer

PURPOSE

The aim of this study was to determine whether collagen XVIII expression is correlated with circulating serum endostatin and whether this has any prognostic value in patients with non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Serum endostatin levels were measured quantitatively by a competitive enzyme immunoassay, and collagen XVIII expression in tumor tissue was investigated with an immunohistochemical method in a series of 94 patients who underwent surgery for NSCLC.

RESULTS

Sixty cases (63.8%) had positive immunohistochemical staining with anticollagen XVIII polyclonal antibodies, including strongly positive staining in 11 (11.7%) cases. The mean (+/- SD) serum endostatin level was 41.6 +/- 34.4 ng/ml in the patient group and 16.3 +/- 10.3 ng/ml in the control group (P < 0.0001). The 11 cases who were strongly collagen XVIII-positive had significantly higher serum endostatin levels than the cases who were negative or weakly positive (P = 0.0297). The 5-year survival rates of negative, weakly positive, and strongly positive patients were 77.8%, 56.9%, and 43.8%, respectively. The cases with strongly positive collagen XVIII expression had a significantly poorer outcome than cases with negative expression (P = 0.0027). A multivariate analysis with Cox proportional hazards model for disease-specific survival revealed that expression of collagen XVIII (strongly positive versus negative; weakly positive versus negative), tumor classification, and regional lymph node classification were independent prognostic factors.

CONCLUSIONS

Our results suggest that expression of collagen XVIII in tumor tissue is strongly associated with a poorer outcome in NSCLC and correlates with elevated levels of circulating serum endostatin.

Disparate effects of endostatin on tumor vascular perfusion and hypoxia in two murine mammary carcinomas

PURPOSE

Recent results in the literature have demonstrated that the antiangiogenic agent endostatin can enhance antitumor effects when administered before or during radiotherapy. To better understand the underlying pathophysiologic basis for this radiosensitization, the current study investigated whether short-term endostatin administration is linked to alterations in tumor vascular perfusion and oxygen delivery.

METHODS AND MATERIALS

Three daily doses of recombinant endostatin (20 mg/kg) were administered to two murine mammary carcinomas, the highly vascularized MCa-35 and the less vascularized MCa-4. Image analysis techniques were used to quantify (1) total and perfused vascular spacing, and (2) changes in tumor hypoxia as a function of distance from the nearest blood vessel.

RESULTS

In MCa-35 tumors, endostatin had no effect on vessel spacing, tumor hypoxia, or tumor growth. In MCa-4 tumors, total and perfused vessel spacings were also unchanged, but tumor growth was inhibited, and tumor hypoxia significantly decreased. These tumors demonstrated an increased vascular functionality suggestive of an increase in the number of intermittently perfused vessels, without corresponding alterations in tumor oxygen consumption rate.

CONCLUSIONS

Poorly vascularized, hypoxic mammary carcinomas were much more responsive to short-term endostatin treatment than well-vascularized, more homogeneously oxygenated tumors. Oxygen levels in the responsive tumors were transiently improved after treatment, which could have substantial implications with respect to the therapeutic effectiveness of combining antiangiogenic agents with conventional therapies.

Retroviral endostatin gene transfer inhibits growth of human lung cancer in a murine orthotopic xenotransplant model

BACKGROUND AND AIMS

The administration of endostatin, a potent anti-angiogenic agent, will be required for extended periods of time as a cancer treatment. The aim of the present study was to induce endogenous endostatin secretion in a continuous fashion, based on retroviral gene transfer. The tumor response was evaluated in an orthotopic murine tumor model of human lung cancer.

MATERIALS AND METHODS

Human non-small-cell lung cancer cells (KNS 62) were retrovirally transduced with the human endostatin gene. An orthotopic murine xenotransplant model was used to investigate tumor growth, metastases and survival. After 4 weeks of subcutaneous growth, endostatin expression was measured by immunoblot analysis in tumor lysates.

RESULTS

The growth of the subcutaneous tumors was significantly delayed, and orthotopic tumor growth and pleural metastases were significantly reduced in endostatin-transduced KNS 62 tumors. Prolongation of survival subsequent to orthotopic tumor induction was demonstrated. Strong endostatin expression was found in subcutaneous tumors after 4 weeks.

CONCLUSION

Retroviral transduction of the human endostatin gene is capable of achieving long-term endostatin expression. Endostatin transduction provides significant anti-tumor effects with regard to local tumor growth, metastases and survival.

Continuous versus intermittent administration of human endostatin in xenografted human neuroblastoma

PURPOSE

The authors examined whether recombinant human endostatin (rhEndostatin), an antiangiogenic agent, is effective against a human neuroblastoma cell line (designated TNB9) using a human neuroblastoma xenograft model and investigated whether continuous infusion is more effective than intermittent administration.

METHODS

In the first experiment, when tumors on the back of nude mice reached a weight of 90 to 95 mg, rhEndostatin, 10 mg/kg/d mouse weight, was administered subcutaneously to the mice (n = 5) every day for 10 consecutive days. In the second experiment, the same daily dose of rhEndostatin was administered continuously to the TNB9-bearing mice (n = 6) via subcutaneous infusion pumps for 3 consecutive days with total dose being 30% of that in the first experiment. Nestin and factor VIII expression levels were studied immunohistochemically to elucidate whether histologic evidence of the effects of rhEndostatin was present on day 4 in the second experiment.

RESULTS

In the first experiment, relative tumor weight in treated mice (n = 5) was significantly less than that in controls (n = 12) on day 2 only after treatment initiation (P <.05). The maximum inhibition rate (MIR) of TNB9 xenograft growth by rhEndostatin was 46.4%, indicating lack of efficacy. In the second experiment, the effects of rhEndostatin were much more marked than those in the first experiment, with an MIR of 60.7%. The mean relative tumor weight in the treated group (n = 6) in the second experiment was significantly less than that in controls (n = 10) on days 2, 4, and 6 (P <.01) as well as on days 8 and 10 (P <.05). Nestin staining in the endothelium of control tumors (n = 2) was marked, whereas it showed a loss of fibrillar structure in rhEndostatin-treated tumors (n = 2). The number of vessels immunostained with antifactor VIII antibody was markedly reduced in tumors (n = 2) from rhEndostatin-treated mice compared with that in tumors from control animals (n = 2).

CONCLUSIONS

Continuous administration of rhEndostatin resulted in more significant tumor regression than intermittent administration of the agent in the same model. This indicates that rhEndostatin, if administered in continuous fashion, could become an effective agent for treating patients with neuroblastoma in the future.

Measurement of renal tumour and normal tissue perfusion using positron emission tomography in a phase II clinical trial of razoxane

Measurement of tumour and normal tissue perfusion in vivo in cancer patients will aid the clinical development of antiangiogenic and antivascular agents. We investigated the potential antiangiogenic effects of the drug razoxane by measuring the changes in parameters estimated from H(2)(15)O and C(15)O positron emission tomography (PET) to indicate alterations in vascular physiology. The study comprised 12 patients with primary or metastatic renal tumours >3 cm in diameter enrolled in a Phase II clinical trial of oral razoxane. Perfusion, fractional volume of distribution of water (VD) and blood volume (BV) were measured in tumour and normal tissue before and 4-8 weeks after treatment with 125 mg twice-daily razoxane. Renal tumour perfusion was variable but lower than normal tissue: mean 0.87 ml min(-1) ml(-1) (range 0.33-1.67) compared to renal parenchyma: mean 1.65 ml min(-1) ml(-1) (range 1.16-2.88). In eight patients, where parallel measurements were made during the same scan session, renal tumour perfusion was significantly lower than in normal kidney (P=0.0027). There was no statistically significant relationship between pretreatment perfusion and tumour size (r=0.32, n=13). In six patients scanned before and after razoxane administration, there was no statistically significant change in tumour perfusion: mean perfusion pretreatment was 0.81 ml min(-1) ml(-1) (range 0.46-1.26) and perfusion post-treatment was 0.72 ml min(-1) ml(-1) (range 0.51-1.15, P=0.15). Tumour VD and BV did not change significantly following treatment: mean pretreatment VD=0.66 (range 0.50-0.87), post-treatment VD=0.71 (range 0.63-0.82, P=0.22); pretreatment BV=0.18 ml ml(-1) (range 0.10-0.25), post-treatment BV=0.167 ml ml(-1) (range 0.091-0.24, P=0.55). Tumour perfusion, VD and BV did not change significantly with tumour progression. This study has shown that H(2)(15)O and C(15)O PET provide useful in vivo physiological measurements, that even highly angiogenic renal cancers have poor perfusion compared to surrounding normal tissue, and that PET can provide valuable information on the in vivo biology of angiogenesis in man and can assess the effects of antiangiogenic therapy.

Delivery of endostatin in experimental cancer therapy

Endostatin, the 20 kDa C-terminal fragment of collagen XVIII, has been shown to be an effective inhibitor of tumour angiogenesis and growth in different experimental systems and is currently in Phase II/III clinical trials. One challenging aspect of anti-angiogenic treatment is the mode of delivery of the active compound. In this paper we review some of the basic knowledge of endostatin and look specifically into the different possible ways in which endostatin may be administered.

New functional roles for non-collagenous domains of basement membrane collagens

Collagens IV, XV and XVIII are major components of various basement membranes. In addition to the collagen-specific triple helix, these collagens are characterized by the presence of several non-collagenous domains. It is clear now that these ubiquitous collagen molecules are involved in more subtle and sophisticated functions than just the molecular architecture of basement membranes, particularly in the context of extracellular matrix degradation. Degradation of the basement membrane collagens occurs during numerous physiological and pathological processes such as embryonic development or tumorigenesis and generates collagen fragments. These fragments are involved in the regulation of functions differing from those of their original intact molecules. The non-collagenous C-terminal fragment NC1 of collagen IV, XV and XVIII have been recently highlighted in the literature because of their potential in reducing angiogenesis and tumorigenesis, but it is clear that their biological functions are not limited to these processes. Proteolytic release of soluble NC1 fragments stimulates migration, proliferation, apoptosis or survival of different cell types and suppresses various morphogenetic events.

Antiangiogenic and antitumor effects of endostatin on follicular thyroid carcinoma

Tumor growth and metastasis depend on blood supply and blood vessel formation. Angiogenesis, therefore, represents a promising target for cancer therapy. Endostatin is one of the most potent antiangiogenic factors and has been shown to effectively inhibit angiogenesis and tumor growth in a variety of in vivo models. In this study, we tested the effects of endostatin on xenografted human follicular thyroid carcinoma (FTC) in nude mice. Our result demonstrated that recombinant endostatin significantly inhibited the growth of FTC xenografts. Furthermore, we established an endostatin-expressing FTC cell line (FTC-BmEndo) using retrovirus-mediated gene transfer approach. We found that the in vivo growth of FTC-BmEndo cells was significantly inhibited, compared with the parental FTC cells, whereas both lines grew at the same rate in vitro. High-level expression of endostatin within the FTC-BmEndo tumors was evidenced by immunohistochemical staining, paralleled with a reduced microvessel density. The systemic level of vascular endothelial growth factor was significantly lower in mice bearing the FTC-BmEndo tumors than in those bearing parental FTC tumors. By using two different approaches, namely the recombinant endostatin protein and the gene therapy strategy, our study demonstrated that endostatin could be effective in suppressing the growth of human FTC in immunodeficient mice.

Angiogenesis modulation in cancer research: novel clinical approaches

Angiogenesis--the formation of new blood vessels--is essential for tumour progression and metastasis. Consequently, the modulation of tumour angiogenesis using novel agents has become a highly active area of investigation in cancer research, from the bench to the clinic. However, the great therapeutic potential of these agents has yet to be realized, which could, in part, be because the traditional strategies that are used in clinical trials for anticancer therapies are not appropriate for assessing the efficacy of agents that modulate angiogenesis. Here, we discuss methods for monitoring the biological activity of angiogenic modulators, and innovative approaches to trial design that might facilitate the integration of these agents into anticancer therapy.