Enhancement of radiation effects by pXLG-mEndo in a lung carcinoma model

Strategies to prolong drug retention in solid tumors by aggregating Endo-CMC nanoparticles

Developing a highly effective nano-drug delivery system with sufficient drug permeability and retention in tumors is still a major challenge for oncotherapy. Herein, a tumor microenvironment responsive, aggregable nanocarriers embedded hydrogel (Endo-CMC@hydrogel) was developed to inhibit the tumoral angiogenesis and hypoxia for enhanced radiotherapy. The antiangiogenic drug (recombinant human endostatin, Endo) loaded carboxymethyl chitosan nanoparticles (Endo-CMC NPs) was wrapped by 3D hydrogel to comprise the Endo-CMC@hydrogel. After peritumoral injection, the Endo-CMC NPs were released, invaded deeply into the solid tumor, and cross-linked with intratumoral calcium ions. The cross-linking process enabled these Endo-CMC NPs to form larger particles, leading to long retention in tumor tissue to minimize premature clearance. This Endo-CMC@hydrogel, integrating the abilities of good tumoral penetration, long retention of anti-drug, and alleviation of hypoxia in tumor tissue, greatly improved the therapeutic effect of radiotherapy. This work provides a proof-of-concept of tumor microenvironment-responding and an aggregable nano-drug delivery system as promising antitumor drug carriers for effective tumor therapy.

Radiation and Endostatin Gene Therapy in a Lung Carcinoma Model: Pilot Data on Cells and Cytokines that Affect Angiogenesis and Immune Status

The dose of radiation that can be safely delivered to cancers residing in sensitive areas such as the lungs is limited by concern for normal tissue damage. Therapies that target tumor vasculature have potential to enhance the efficacy of radiotherapy, with minimal risk for toxicity. We constructed a unique plasmid, pXLG-mEndo, containing the mouse endostatin gene. A significantly greater anti-tumor effect was obtained against Lewis lung carcinoma (LLC) in mice when pXLG-mEndo was combined with radiation compared to radiation alone. Here we report results of cellular and cytokine assessments performed one day after treatment. These analyses were done to obtain baseline data on leukocytes that affect angiogenesis, as well as anti-tumor immunity, and to detect possible treatment-related toxicities. White blood cell counts were dramatically elevated in blood and spleens of untreated tumor-bearing mice, primarily due to granulocytosis. Overall, the effect of radiation was more evident than that of the plasmids (pXLG-mEndo and parental pWS4); radiosensitivity of specific lymphocyte subsets was variable (B > T > NK; CD8+ Tc > CD4+ Th). Tumor presence resulted in dramatically elevated interleukin-2 (IL-2) and decreased tumor necrosis factor-α (TNF-α) in supernatants of activated splenocytes, but had no significant effect on interferon-γ (IFN-γ). Administration of pXLG-mEndo, radiation, or both modified the tumor-induced aberrations in IL-2 and TNF-α; IFN-γ production was decreased by radiation. Red blood cell counts, hemoglobin, and hematocrit were low in tumor-bearing mice, but there were no treatment-related differences among groups. Platelet counts were reduced, whereas their volumes were increased in tumor-bearing mice; both parameters were only slightly affected by either pXLG-mEndo or control plasmid injection, however. The data demonstrate in the Lewis lung carcinoma model that tumor-localized endostatin gene therapy and radiation had significant effects on cells and cytokines that can influence angiogenesis, tumor growth, and immune status.

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).

Endostatin and endorepellin: A common route of action for similar angiostatic cancer avengers

Traditional cancer therapy typically targets the tumor proper. However, newly-formed vasculature exerts a major role in cancer development and progression. Autophagy, as a biological mechanism for clearing damaged proteins and oxidative stress products released in the tumor milieu, could help in tumor resolution by rescuing cells undergoing modifications or inducing autophagic-cell death of tumor blood vessels. Cleaved fragments of extracellular matrix proteoglycans are emerging as key players in the modulation of angiogenesis and endothelial cell autophagy. An essential characteristic of cancer progression is the remodeling of the basement membrane and the release of processed forms of its constituents. Endostatin, generated from collagen XVIII, and endorepellin, the C-terminal segment of the large proteoglycan perlecan, possess a dual activity as modifiers of both angiogenesis and endothelial cell autophagy. Manipulation of these endogenously-processed forms, located in the basement membrane within tumors, could represent new therapeutic approaches for cancer eradication.

Inhibitory effect of endostatin combined with paclitaxel-cisplatin on breast cancer in xenograft-bearing mice

In the present study, we aimed to investigate the tumor-inhibiting effects of recombinant human endostatin (rhES) combined with paclitaxel-cisplatin (TP regimen) on human breast cancer in xenograft-bearing nude mice. A total of 24 mice bearing human breast cancer xenografts were administered both rhES and TP, TP alone, rhES alone or saline. The tumor growth inhibition was observed. Serum vascular endothelial growth factor (VEGF) levels and microvessel density (MVD) were determined by ELISA and immunohistochemistry, respectively. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining. Survival time was observed in another 24 nude mice with the same treatment. MVD expression in the group administered rhES and TP was lower than that in the other groups (P<0.05); serum VEGF levels in the combined drug group were lower compared to the other groups; the apoptotic index increased in the combined drug group. We conclude that the effect of the TP regimen combined with rhES on breast cancer is better than that of the TP regimen alone.

Endostar down-regulates HIF-1 and VEGF expression and enhances the radioresponse to human lung adenocarcinoma cancer cells

To study the effect of endostar on the expression of hypoxia-inducible factor 1 (HIF-1) and vascular endothelial growth factor (VEGF) and radiosensitization, the changes of A549 cells treated by endostar, radiotherapy and radiotherapy plus endostar were checked by flow cytometry (FCM), methyl thiazolyl tetrazolium (MTT), hoechst staining, and enzyme linked immunosorbent assay (ELISA). The results showed that endostar could block cell periods of A549 and stopped the cell cycle at G2/M and S periods. Cell growth inhibiting and apoptotic rate in the combination group were higher than those in other groups. Meanwhile, the levels of HIF-1 and VEGF expression in the combination group were lower than those of other groups. It suggested that endostar significantly sensitizes the function of radiation in A549 cells by arresting the cell cycle at stage of G2/M and S, increasing the cell growth inhibiting and the apoptotic rate, down-regulating the expression of HIF-1 and VEGF.

Inhibitory effect of endostar in combination with radiotherapy in a mouse model of human CNE2 nasopharyngeal carcinoma

The inhibitory effects of Endostar in combination with radiotherapy in BALB/c nude mice model of human CNE2 nasopharyngeal carcinoma and the mechanism were investigated. In nude mice model of CNE2 nasopharyngeal carcinoma, the inhibitory rate and the sensitizing enhancement ratio (E/O) were calculated according to the tumor volumes in different groups. The expression of microvascular density (MVD) in tumor tissues was examined by using immunohistochemistry staining. The transcription of VEGF gene was detected by using RT-PCR. The inhibitory rate in Endostar+ radiotherapy group was higher than in other groups. In Endostar+radiotherapy group, the tumor volume was significantly decreased and the E/O ratio was 2.335, suggesting that Endostar could be a radiosensitizer. The expression of MVD of tumor tissues in Endostar+radiotherapy group was reduced significantly. The expression of the MVD in treatment groups was significantly different from that in control group (P<0.05). Compared to other groups, VEGF mRNA expression in Endostar+radiotherapy group was decreased remarkably. Endostar in combination with radiotherapy significantly inhibited the growth of CNE2 tumor. The combination therapy decreased the expression of VEGF, and inhibited tumor angiogenesis and proliferation. When combined with radiotherapy, Endostar acted as a radiosensitizer.

Low density lipoprotein receptor mediates anti-VEGF effect of lymphocyte T-derived microparticles in Lewis lung carcinoma cells

Nonstop proliferation and vigorous neovascularization are two prominent characteristics of cancer. Antiangiogenic therapy has emerged as an important modality in treatment of solid tumors. Our previous work demonstrated that microparticles derived from apoptotic T-lymphocytes (LMPs) not only reduced the viabilities of high-proliferating cells, but also exhibited potent antiangiogenic effects through inhibition of the vascular endothelial growth factor (VEGF)/VEGF receptor 2 signalling pathway. In the present study, we extended these studies to explore the anticancer potential of LMPs using a murine model of Lewis lung carcinoma (LLC). Results show that intratumoral injection of LMPs (2.5 mg/kg) decreased tumor size by more than 50% relative to control. Tumor microvessel density and VEGF-A levels were also markedly reduced upon LMPs treatment. To elucidate the underlying mechanisms of LMPs-mediated antitumor activity, LLC cells were utilized in in vitro experiments. LMPs suppressed VEGF-A protein levels in LLC cells and led to inhibition of LLC cell viability and proliferation. In addition, knockdown of the low-density lipoprotein receptor (LDLR) expression reduced the uptake of LMPs into LLC cells and attenuated the inhibitory effects of LMPs on cell growth and VEGF-A expression. Our findings demonstrate that LMPs exert antiangiogenic and proapoptotic effects that lead to inhibition of lung carcinoma by reducing VEGF-A levels and LDLR mediates the anti-VEGF effect of LMPs through translocating LMPs into LLC cells. These results suggest that LMPs are promising antiangiogenic therapeutic agent and represent a new therapeutic strategy for treating lung carcinomas.

[Effects of rh-endostar in combination with radiotherapy on rats with lung cancer]

BACKGROUND AND OBJECTIVE

Radiation sensitivity is closely related to tissue oxygen, and rh-endostatin can induce the high level of oxygen content in tumor by "normalizing" tumor angiogenesis which is associated with radiotherapy sensitivity. The aim of this study is to observe the effect of combination of radiotherapy with rh-endostatin in the rats with lung cancer.

METHODS

Immediate lewis cancerous ascetic injection method was used to make rats tumors bearing model, then the rats was divided into four groups randomly: group A was treated with saline; group B was treated with rh-endostatin; group C was treated with irradiation and group D was treated with rh-endostatin and irradiation. After all rats were treated, inhibition rates and the tumor growth curve were calculated. Immunohistochemisty was adopted to check the expressions of vascular endothelial growth factor (VEGF) and microvessel density (MVD).

RESULTS

Compared with group A, the growth rates of the tumors in the other group were obviously slower, and the tumor weights were significantly different form group A (P < 0.05). Compared with the other groups, the tumor weights of group D were obviously reduced (P < 0.05). Compared with group A, VEGF and MVD of other three groups were reduced (P < 0.05), and group D were significantly cut down.

CONCLUSION

Combination with radiotherapy and rh-endostatin could inhibit the lung cancer significantly in rats. The possible mechanisms are to decrease the expression ofVEGF and inhibit the production of angiogenesis.

Future prospects and challenges of antiangiogenic cancer gene therapy

In 1971 Judah Folkman proposed the concept of antiangiogenesis as a therapeutic target for cancer. More than 30 years later, concept became reality with the approval of the antivascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab as a first-line treatment for metastatic colorectal cancer. Monoclonal antibodies and small molecular drugs are the most widely applied methods for inhibition of angiogenesis. The efficacy of these antiangiogenic modalities has been proven, in both preclinical and clinical settings. Although angiogenesis plays a major role in wound healing, hypoxia, and in the female reproductive cycle, inhibition of angiogenesis seems to be a relatively safe therapeutic option against cancers, and has therefore become a logical arena for a wide range of experimentation. The twentieth century has shown the boom of gene therapy and thus it has been applied also in the antiangiogenic setting. This review summarizes methods to induce antiangiogenic responses with gene therapy and discusses the obstacles and future prospects of antiangiogenic cancer gene therapy.

Angiogenesis inhibitors and the need for anti-angiogenic therapeutics

Angiogenesis is the formation of new blood vessels from pre-existing vessels to form capillary networks, which, among other diseases, such as diabetic retinopathy and macular degeneration, is particularly important for tumor growth and metastasis. Thus, depriving a tumor of its vascular supply by means of anti-angiogenic agents has been of great interest since its proposal in the 1970s. This review looks at the common angiogenic inhibitors (angiostatin, endostatin, maspin, pigment epithelium-derived factor, bevacizumab and other monoclonal antibodies, and zoledronic acid) and their current status in clinical trials.

Inhibition of corneal neovascularization with endostatin delivered by adeno-associated viral (AAV) vector in a mouse corneal injury model

The use of a recombinant adeno-associated viral (rAAV) vector carrying endostatin gene as an anti-angiogenesis strategy to treat corneal neovascularization in a mouse model was evaluated. Subconjunctival injection of recombinant endostatin-AAV was used to examine the inhibition of corneal neovascularization induced by silver nitrate cauterization in mice. The results showed that gene expression in corneal tissue was observed as early as 4 days after gene transfer and stably lasted for over 8 months with minimal immune reaction. Subconjunctival injection of a high-titer rAAV-endostatin successfully inhibited neovascularization. Immunohistchemistry staining of CD 31 and endostatin showed that the treatment significantly inhibits angiogenesis in cornea. We concluded that the rAAV was capable of directly delivering genes to the ocular surface epithelium by way of subconjunctival injection and was able to deliver sustained, high levels of gene expression in vivo to inhibit angiogenesis.