Continuous versus intermittent administration of human endostatin in xenografted human neuroblastoma

Different administration routes of recombinant human endostatin combined with concurrent chemoradiotherapy might lead to different efficacy and safety profile in unresectable stage III non-small cell lung cancer: Updated follow-up results from two phase II trials

Background

There are two main choices of administration route of recombinant human endostatin (Endostar) available and the treatment options of concurrent chemoradiotherapy (CCRT) have changed over time. The aim of this study was to observe the long‐term efficacy and safety of different administration routes of Endostar combined with CCRT.

Methods

Patients with unresectable stage III non‐small cell lung cancer (NSCLC) from two phase II trials were included as two cohorts. Both were treated with Endostar combined with CCRT. Endostar was administrated by intravenous injection (7.5 mg/m²/day, seven days) in the IV arm and by continuous intravenous pumping (7.5 mg/m²/24 hours, 120 hours) in the CIV arm.

Results

A total of 48 patients were included in the IV arm and 67 patients in the CIV arm. The median progression‐free survival (PFS), overall survival (OS), local recurrence‐free survival (LRFS) and distant metastasis‐free survival (DMFS) in the IV arm and CIV arm were 9.9 months versus 15.4 months (HR = 0.751, 95% CI 0.487–1.160, P = 0.200), 24.0 months versus 38.5 months (HR = 0.746, 95% CI 0.473–1.178, P = 0.209), 32.3 months versus 27.1 months (HR = 1.193, 95% CI 0.673–2.115, P = 0.546), 20.1 months versus 49.7 months (HR = 0.603, 95% CI 0.351–1.036, P = 0.067). The one, three, five‐year PFS in the IV arm and CIV arm was 45.8% versus 52.9%, 18.3% versus 31.4%, and 18.3% versus 27.7% and the one, three, five‐year OS was 81.2% versus 82.1%, 31.1% versus 50.3%, and 31.1% versus 41%, respectively. Incidence of hematological adverse reactions were numerically lower in the CIV arm than the IV arm.

Conclusions

Endostar delivered by CIV with CCRT may be a better option than IV in terms of potential survival and safety for unresectable stage III NSCLC.

Key points

Significant findings of the study Endostar delivered by continuous intravenous pumping might achieve more favorable survival over intravenous injection and reduce adverse hematological reactions in patients with unresectable stage III NSCLC treated with Endostar combined with CCRT.What this study adds The administration route of recombinant human endostatin is also one key factor for survival and safety to consider when treating patients with unresectable stage III NSCLC.

Influence of different drug delivery methods for Endostar combined with a gemcitabine/cisplatin regimen in locally advanced or metastatic lung squamous cell carcinoma: A retrospective observational study

Continuous endovenous administration of Endostar (CE) gradually replaced drip intravenous administration of Endostar (DE) in lung squamous cell carcinoma (SCC) treatment presently, but the efficacy and safety of CE and DE which is better in advanced lung SCC are yet unclear. To evaluate the feasibility of CE as an alternative to DE with gemcitabine/cisplatin (GP) chemotherapy. Data were collected from patients admitted with locally advanced or metastatic lung SCC from January 2011 to April 2015, including the patients' characteristics, the therapeutic regimen, the treatment effectiveness, and toxicity. There are 71 patients with pathologically confirmed lung SCC retrospectively assigned to a treatment (CE) group of 48 patients and a control (DE) group of 23 patients. The response of each tumor to the therapy was assessed every 2 cycles by a chest and upper abdomen computed tomography for the comparison of curative effects and adverse reactions. Compared with the DE group, the response rate and disease control rate were noninferior in the CE group. The median progression-free survival and overall survival in the CE and DE groups were no significantly difference (5.5 vs 5.5 months, P = .141; 22.9 vs 14.3 months, P = .053). Increased progression-free survival (PFS) for patients in CE group was observed across 3 subgroups analyzed. There was a 35.7% reduction in the total dose of Endostar per cycle in the CE group compared with that in the DE group. Thus, in combination with GP chemotherapy, CE could be a suitable alternative to DE in locally advanced or metastatic SCC patients, resulting in less hemoptysis, less treatment time, and lower costs.

Effect of Endostatin on Preventing Postoperative Progression of Distant Metastasis in a Murine Lung Cancer Model

Aims and Background

The relapse and metastasis of cancer remain a predominant cause of death after surgical removal of the primary tumor. There is a positive linkage between the postoperative upregulation of systemic angiogenic activity and distant tumor metastasis. In the present study, we established a spontaneous metastasis model and investigated whether antiangiogenic therapy using endostatin could prevent the progression of distant metastasis after removal of the primary tumor.

Methods

Female C57BL/6 mice were implanted subcutaneously with 1 × 106 Lewis lung cancer cells. Twenty days after implantation of the cancer cells, the primary tumor was removed and the mice were randomly divided into three groups. The NS group received normal saline, the L-ES group received 3 mg/kg endostatin, and the H-ES group received 20 mg/kg endostatin intravenously daily for 10 days. The effect of endostatin on lung metastases and the survival time of the mice were observed. Flow cytometry and immunohistochemistry were carried out to assess the angiogenic activity. The serum endostatin levels in peripheral blood were measured using an enzyme-linked immunosorbent assay.

Results

The mean number of metastatic pulmonary nodules and the mean net lung weight in the NS, L-ES and H-ES groups was 10.2, 2.8 and 4.0, and 0.55g, 0.31g and 0.36g, respectively. The difference between the NS group and the endostatin-treated groups was statistically significant (P <0.05). The endostatin-treated mice showed prolonged overall survival (P <0.05). Compared with the NS group, the endostatin-treated groups had lower levels of circulating endothelial cells in peripheral blood and showed a decrease in microvessel density in the metastatic tumors, with a more marked reduction in the L-ES group (P <0.05). The systemic presence of endostatin was gradually increased with the continued administration of endostatin to the mice.

Conclusions

Antiangiogenic therapy with endostatin is effective in inhibiting the postoperative progression of distant metastasis.

Tumor refractoriness to endostatin anti-angiogenesis is associated with the recruitment of CD11b+Gr1+ myeloid cells and inflammatory cytokines

Aims and background

A major challenge in developing antiangiogenic therapies is tumor intrinsic refractoriness and the emergence of treatment-induced resistance. Recently, such resistance is considered to be associated with inflammatory changes in the tumor microenvironment. However, no information has been acquired about the effect of endostatin on tumor microenvironment in this field. We established two tumor models refractory to endostatin treatment and sought to determine the role of inflammatory changes in the development of tumor refractoriness to antiangiogenic therapy.

Methods

Three xenograft tumor murine models were treated with low-dose endostatin or high-dose endostatin for 10 days. The effect of endostatin on tumor growth was observed, and tumors refractory to endostatin treatment were defined. Flow cytometry were carried out to assess the presence of CD11b+Gr1+ myeloid cells in the peripheral blood and in the tumor. Inflammatory cytokine levels in peripheral blood were measured using the enzyme-linked immunosorbent assay. The expression of NF-κB, versican and hypoxia-inducible factor-1α in the tumor was evaluated using immunohistochemistry.

Results

LLC and B16F1 tumors were defined as animal models of refractoriness to endostatin treatment. CD11b+Gr1+ myeloid cells were inherently recruited into the peripheral blood and the tumor microenvironment in the LLC tumor-bearing mice, and levels of serum G-CSF and TNF-α were increased along with the progression of tumor growth. In the B16F1 tumor-bearing mice, CD11b+Gr1+ myeloid cells were acquiredly recruited by endostatin into the peripheral blood and the tumor microenvironment. Additionally, high levels of G-CSF and TNF-α in serum and high expression of NF-κB, versican and hypoxia-inducible factor-1α in tumor tissue were found in B16F1 tumor-bearing mice after endostatin administration.

Conclusions

A tumor can grow inherently or acquiredly with refractoriness to endostatin treatment in vivo. Recruitment of CD11b+Gr1+ myeloid cells and inflammatory cytokines may play an important role in the development of tumor refractoriness to endostatin anti-angiogenesis.

Preparation of endostatin-loaded chitosan nanoparticles and evaluation of the antitumor effect of such nanoparticles on the Lewis lung cancer model

The purpose of this study was to prepare ES-loaded chitosan nanoparticles (ES-NPs) and evaluate the antitumor effect of these particles on the Lewis lung cancer model. ES-NPs were prepared by a simple ionic cross-linking method. The characterization of the ES-NPs, including size distribution, zeta potential, loading efficiency and encapsulation efficiency (EE), was performed. An in vitro release test was also used to determine the release behavior of the ES-NPs. Cell viability and cell migration were assayed to detect the in vitro antiangiogenic effect of ES-NPs. In order to clarify the antitumor effect of ES-NPs in vivo, the Lewis lung cancer model was used. ES-NPs were successfully synthesized and shown to have a suitable size distribution and high EE. The nanoparticles were spherical and homogeneous in shape and exhibited an ideal releasing profile in vitro. Moreover, ES-NPs significantly inhibited the proliferation and migration of human umbilical vascular endothelial cells (HUVECs). The in vivo antiangiogenic activity was evaluated by ELISA and immunohistochemistry analyses, which revealed that ES-NPs had a stronger antiangiogenic effect for reinforced anticancer activity. Indeed, even the treatment cycle in which ES-NPs were injected every seven days, showed stronger antitumor effect than the free ES injected for 14 consecutive days. Our study confirmed that the CS nanoparticle is a feasible carrier for endostatin to be used in the treatment of lung cancer.

Anti-angiogenesis in neuroblastoma

The nature of the angiogenic balance in neuroblastoma is complex, and a spectrum of angiogenesis stimulators and inhibitors have been detected in neuroblastoma tumours. The complex relationships between angiogenic cascade and anti-angiogenic agents in the tumour vascular phase have indicated that anti-angiogenesis can be considered as a strategy for the adjuvant therapy of neuroblastoma. The major goal is to establish if inhibition of angiogenesis is a realistic therapeutic strategy for inhibiting tumour cell dissemination and the formation of metastasis in neuroblastoma.

Suitable carriers for encapsulation and distribution of endostar: comparison of endostar-loaded particulate carriers

Background

Particulate carriers are necessary to control the release of endostar and prolong its circulation in vivo. The purpose of this study was to identify a suitable carrier for the capsulation and delivery of endostar.

Methods

We prepared a series of poly (DL-lactide-co-glycolide) (PLGA) and poly (ethylene glycol) (PEG)-modified PLGA (PEG-PLGA) particulate carriers, and then characterized them according to their ability to prolong the circulation of endostar, their physicochemical properties, endostar-loading content, and in vitro and in vivo particulate carrier release profiles.

Results

All the particulate carriers had spherical core shell structures. The PEG-PLGA material and nanosize range appeared to enable the carriers to encapsulate more endostar, release endostar faster in vitro, and accumulate more endostar in vivo. The drug loading capacity of PEG-PLGA and PLGA nanoparticles was 8.03% ± 3.41% and 3.27% ± 5.26%, respectively, and for PEG-PLGA and PLGA microspheres was 15.32% ± 5.61% and 9.21% ± 4.73%. The cumulative amount of endostar released from the carriers in phosphate-buffered saline over 21 days was 23.79%, 20.45%, 15.13%, and 10.41%, respectively. Moreover, the terminal elimination half-life of endostar in the rabbit was 26.91 ± 7.93 hours and 9.32 ± 5.53 hours in the PEG-PLGA group and the PLGA nanoparticle group. Peak endostar concentration was reached at day 7 in the group treated with subcutaneous injection of PEG-PLGA microspheres and at day 14 in the group receiving subcutaneous injection of PLGA microspheres. Endostar was detectable in vivo in both groups after injection of the particulate carriers.

Conclusion

PEG-PLGA nanoparticles might be better than other nanoparticulate carriers for encapsulation and distribution of endostar.

Inhibitory effect of drug-free hybrid liposomes on metastasis of human neuroblastoma

PURPOSE

Hybrid liposomes composed of vesicular and micellar molecules have been used as drug-delivery systems. It has become clear that hybrid liposomes alone have an inhibitory effect against the growth of various tumor cells. The present study was designed to determine whether a drug-free hybrid liposome composed of dimyristoylphosphatidylcholine (DMPC) and polyoxyethylenealkyl ether (EO) [90 mol% DMPC/10% C(12)(EO)(21) (HL21), 90 mol% DMPC/10% C(12)(EO)(23) (HL23), or 90 mol% DMPC/10% C(12)(EO)(25) (HL25)], inhibit the liver metastasis of human neuroblastoma cells and thus increases survival.

METHODS

A human neuroblastoma cell, TNB9, and BALB/C-nu/nu athymic mice were used in this study. First, we determined the inhibitory effect of the hybrid liposomes on TNB9 cells in vitro. Next, to determine the inhibitory effect of the hybrid liposomes on metastasis of neuroblastoma cells to the liver, we made a murine hepatic metastasis model by implanting TNB9 cells (2 × 106) in the spleen of the mice and compared anatomic appearance, weights, and histological findings of the livers of treated mice and control mice 60 days after the beginning of a 7-day intraperitoneal injection of a hybrid liposome. We also compared survival rates using the Kaplan-Meier method.

RESULTS

In mice implanted with TNB9 neuroblastoma cells and treated with HL21 or HL25, no histological evidence of metastasis was found, the weight of the liver was normal, and survival was a mean of 88 and 87.9 days, respectively. In contrast, mice treated with HL23 and control mice had countless tumor cell masses histologically, their liver weight was increased, and their survival was 73.0 and 68.6 days, respectively.

CONCLUSIONS

Two kinds of hybrid liposomes, HL21 and HL25, inhibit metastasis of human neuroblastoma cells to the liver, and thus increase survival.

New anti-angiogenic strategies in pediatric solid malignancies: agents and biomarkers of a near future

IMPORTANCE OF THE FIELD

Antiangiogenic strategies are affording considerable interest and have become a major milestone in therapeutics of various adult cancers. However, progress has been slow to expand such therapies to patients with pediatric solid malignancies.

AREAS COVERED IN THIS REVIEW

This review discusses the principal pathways for angiogenesis in pediatric solid malignancies and summarizes recent preclinical and clinical data on antiangiogenesis strategies in these tumors.

WHAT THE READER WILL GAIN

The reader will gain state-of-the-art knowledge in the current advancements of antiangiogenic therapies in pediatric clinical trials in regard to supporting preclinical data, and in the status of potential biomarkers investigated for monitoring angiogenesis inhibitors. Mechanisms of resistance to antiangiogenic therapy will also be discussed. Finally, we describe our experience in the monitoring of circulating endothelial cells and progenitors and their potential role as biomarkers of metastatic disease and resistance to antiangiogenic therapies.

TAKE HOME MESSAGE

Evaluation and development of antiangiogenesis protocols are starting and represent a crucial step in the management of pediatric solid malignancies today. Emphasis should be placed on the development of proper surrogate markers to monitor antiangiogenic activity and on the possible long-term effects of these therapies in a pediatric population.

Characterization of a monoPEG20000-Endostar

In this study, we investigated the PEG attachment site of mono-PEGylated Endostar, a modified recombinant human endostatin approved in China for lung cancer. N-terminal site-directed mono-PEGylation of Endostar was accomplished using mPEG-propionaldehyde derivatives (Mw=20 kDa) under slightly acidic pH conditions (pH 5.5). One-step cation exchange chromatography was used to purify the mono-PEGylated Endostar. Following tryptic digestion, the peptide fragment containing PEG was separated by SDS-PAGE. Barium iodide staining and Western blotting were used to detect the PEG moiety and the N-terminus of Endostar, respectively. The peptide fragment stained by barium iodide showed a positive response to anti-(His) 6 mAb, demonstrating that PEG was located at the N-terminus of Endostar. LC/MS was applied to verify the occurrence of mono-PEGylation at the N-terminus of Endostar.

[Potential role of antiangiogenic treatment in neuroblastoma]

Focus on new drug development over the last few years has yielded new agents that differ from unspecific classical chemotherapeutics and ionizing radiation, while still targeting the cancer cell itself. Antiangiogenesis is a totally distinct approach targeting the tumor's blood vessels. This concept has now found its eligibility for the treatment of several adult solid tumors: the human antivascular endothelial growth factor (VEGF) antibody bevacizumab, as well as the VEGF receptor tyrosine kinase inhibitors, sunitinib and sorafinib, have recently been licensed by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) for the treatment of colorectal, renal, and lung cancer. Other antiangiogenic drugs are under preclinical and early clinical evaluation. However, what do we know of the use of these drugs in pediatric solid tumors, such as sarcomas and embryonal and neuronal tumors? For some time now, neuroblastoma has been shown to be dependent on angiogenesis. However, the first preclinical data on antiangiogenic drugs in neuroblastoma have not been published until recently, and clinical trials with antiangiogenic agents in neuroblastoma treatment protocols are scarce. This review adresses current knowledge on the important role and mechanisms of angiogenesis in neuroblastoma and summarizes available preclinical and clinical results of antiangiogenic agents used to treat neuroblastoma. Our review clearly demonstrates that clinical trials are urgently needed to bring forward promising antiangiogenesis concepts in neuroblastoma therapy.

An alternative in vivo system for testing angiogenic potential of human neuroblastoma cells

In this study we purposed an alternative method to study the angiogenic and invasive potential of neuroblastoma cell suspensions implanted on the chick embryo chorioallantoic membrane (CAM) surface. Neuroblastoma cells were seeded in Matrigel and thereafter the suspension was pipetted onto the CAM surface at day 8 of incubation inside a silicon ring previously loaded onto the CAM surface. Four days after implantation, the silicon ring was removed and the angiogenic and invasive response were studied morphologically at macroscopic and microscopic levels and by reverse transcriptase-polymerase chain reaction (RT-PCR) by using human and chicken primers for several angiogenic cytokines, namely vascular endothelial growth factor-A (VEGF-A), fibroblast growth factor-2 (FGF-2), angiopoietin-1 (ANG-1), hypoxia inducible factor-2alpha (HIF-2alpha), and for an endogenous angiostatic molecule, namely endostatin. Results showed that: (1) Neuroblastoma cells induced an angiogenic response in the CAM assay comparable to that induced by FGF-2; (2) neuroblastoma cells are packed inside Matrigel or are recognizable in the CAM mesenchyme; (3) Angiogenic activity of neuroblastoma cells is associated to an high expression of the transcripts of human VEGF-A, FGF-2, ANG-1 and HIF-2alpha and to a low expression in the transcript of a human endostatin while in the control specimens there is no expression of both angiogenic and angiostatic molecules; and (4) the expression of the transcripts of the same chicken angiogenesis stimulators and inhibitor is unmodified in treated and control specimens. Overall, these data indicate that neuroblastoma cells growth on the chick CAM express characteristics of the human disease. This experimental model could be employed for further research on human tumor progression and anti-angiogenic molecules screening.

Tumor-specific expression of the RGD-alpha3(IV)NC1 domain suppresses endothelial tube formation and tumor growth in mice

Angiogenesis plays an essential role in tumor growth. This study investigated expression of the noncollagenous domain of alpha3(IV) collagen (alpha3(IV)NC1) transduced into tumors and its inhibition of tumor growth. We hypothesized that if a human telomerase reverse transcriptase (hTERT) promoter-driven RGD motif containing alpha3(IV)NC1 (hTERT/RGD-alpha3(IV)NC1) were expressed in telomerase-expressing tumor cells, it would inhibit tumor growth by its anti-angiogenic property. Adenoviral transduction of hTERT/RGD-alpha3(IV)NC1 expressed RGD-alpha3(IV)NC1 in hTERT-positive tumor cell lines. However, hTERT/RGD-alpha3(IV)NC1 did not express RGD-alpha3(IV)NC1 in hTERT-negative cells such as keratinocytes and fibroblasts. The secreted RGD-alpha3(IV)NC1 in the conditioned medium from tumor cells inhibited cell proliferation as well as tube formation in cultured endothelial cells, but had no effect on other types of cells. In an in vivo model, adenoviral hTERT/RGD-alpha3(IV)NC1 gene therapy showed limited expression of RGD-alpha3(IV)NC1 in tumors and resulted in a significant decrease of vessel density in tumors. The growth of subcutaneous (s.c.) tumors in nude mice was significantly suppressed by treatment with hTERT/RGD-alpha3(IV)NC1. In addition, long-term inhibition of tumor growth was achieved by intermittent administration of hTERT/RGD-alpha3(IV)NC1. In conclusion, our findings demonstrate that tumor-specific anti-angiogenic gene therapy utilizing RGD-alpha3(IV)NC1 under the hTERT promoter inhibited angiogenesis in tumors, resulting in an antitumor effect.

Endostatin inhibits nitric oxide and diminishes VEGF and collagen XVIII in squamous carcinoma cells

Low pO(2) values are a common finding among oral squamous cell carcinomas (SCC). Our objective was to determine the role that oxygen tension plays on the direct tumor effect of endostatin (ES). Squamous carcinoma cell lines were grown under normoxic or hypoxic conditions and treated with endostatin (ES), nitric oxide (NO) donors, NO scavengers, NO synthase inhibitors, or transduced with AdenoVec-hEndo or AdenoVec Null vectors. The expression of vascular endothelial growth factor (VEGF) and collagen XVIII were determined by RT-PCR and protein levels assessed by Western blot analyses. Our studies demonstrated that collagen XVIII and VEGF are expressed and responsive to ES in a limited number of SCC cell lines during normoxia but were most responsive when grown under hypoxic conditions. VEGF and collagen XVIII were downregulated by both ES and transduction of cells with AdenoVec-hEndo. The effects of ES on SCC cells were enhanced by aminoguanidine (Ag), L-NAME, and diphenyleneiodonium chloride (DPI). Endostatin and transduced with ES vectors diminished the levels of NO whereas NO donors enhanced VEGF expression and collagen XVIII expression. In conclusion, the direct effect of endostatins on tumor cells is most effective under conditions of low oxygen tension and can be potentiated by the use of nitric oxide synthase inhibitors or NO scavengers.

Effects of endostatin on expression of vascular endothelial growth factor and its receptors and neovascularization in colonic carcinoma implanted in nude mice

AIM: To investigate the antiangiogenic effects of endostatin on colonic carcinoma cell line implanted in nude mice and its mechanism.

METHODS: Nude mice underwent subcutaneous injection with LS-174t colonic carcinoma cell line to generate carcinoma and were randomly separated into two groups. Mice received injection of vehicle or endostatin every day for two weeks. After the tumor was harvested, the tumor volumes were determined, and the expressions of CD34, VEGF and Flk-1 were examined by immunohistochemical method.

RESULTS: Tumor volume was significantly inhibited in the endostatin group (84.17%) and tumor weight was significantly inhibited in the endostatin group (0.197 ± 0.049) compared to the control group (1.198 ± 0.105) (F = 22.56, P = 0.001), microvessel density (MVD) was significantly decreased in the treated group (31.857 ± 3.515) compared to the control group (100.143 ± 4.290) (F = 151.62, P < 0.001). Furthermore, the expression of Flk-1 was significantly inhibited in the treated group (34.29%) compared to the control group (8.57%) (χ² = 13.745, P = 0.001). However no significant decrease was observed in the expression of vascular endothelial growth factor (VEGF) between these two groups (χ² = 0.119,P = 0.730).

CONCLUSION: Endostatin can inhibit tumor growth and angiogenesis by blocking Vegf/Flk-1 pathway. This experiment provides the theory basis for developing a new anti-carcinoma drug through studying the properties of anti-angiogenesis inhibitors.