Local inhibition of angiogenesis by halofuginone coated silicone materials

Antifibrotic strategies for medical devices

A broad range of medical devices initiate an immune reaction known as the foreign body response (FBR) upon implantation. Here, collagen deposition at the surface of the implant occurs as a result of the FBR, ultimately leading to fibrous encapsulation and, in many cases, reduced function or failure of the device. Despite significant efforts, the prevention of fibrotic encapsulation has not been realized at this point in time. However, many next-generation medical technologies including cellular therapies, sensors and devices depend on the ability to modulate and control the FBR. For these technologies to become viable, significant advances must be made in understanding the underlying mechanism of this response as well as in the methods modulating this response. In this review, we highlight recent advances in the development of materials and coatings providing a reduced FBR and emphasize key characteristics of high-performing approaches. We also provide a detailed overview of the state-of-the-art in strategies relying on controlled drug release, the surface display of bioactive signals, materials-based approaches, and combinations of these approaches. Finally, we offer perspectives on future directions in this field.

Local anti-angiogenic therapy by magnet-assisted downregulation of SHP2 phosphatase

Anti-angiogenic therapies are promising options for diseases with enhanced vessel formation such as tumors or retinopathies. In most cases, a site-specific local effect on vessel growth is required, while the current focus on systemic distribution of angiogenesis inhibitors may cause severe unwanted side-effects. Therefore, in the current study we have developed an approach for the local inhibition of vascularization, using complexes of lentivirus and magnetic nanoparticles in combination with magnetic fields. Using this strategy in the murine embryonic stem cell (ESC) system, we were able to site-specifically downregulate the protein tyrosine phosphatase SHP2 by RNAi technology in areas with active vessel formation. This resulted in a reduction of vessel development, as shown by reduced vascular tube length, branching points and vascular loops. The anti-angiogenic effect could also be recapitulated in the dorsal skinfold chamber of mice in vivo. Here, site-specific downregulation of SHP2 reduced re-vascularization after wound induction. Thus, we have developed a magnet-assisted, RNAi-based strategy for the efficient local inhibition of angiogenesis in ESCs in vitro and also in vivo.

Antiangiogenic Effect of Alkaloids

Alkaloids are among the natural phytochemicals contained in functional foods and nutraceuticals and have been suggested for the prevention and/or management of oxidative stress and inflammation-mediated diseases. In this review, we aimed to describe the effects of alkaloids in angiogenesis, the process playing a crucial role in tumor growth and invasion, whereby new vessels form. Antiangiogenic compounds including herbal ingredients, nonherbal alkaloids, and microRNAs can be used for the control and treatment of cancers. Several lines of evidence indicate that alkaloid-rich plants have several interesting features that effectively inhibit angiogenesis. In this review, we present valuable data on commonly used alkaloid substances as potential angiogenic inhibitors. Different herbal and nonherbal ingredients, introduced as antiangiogenesis agents, and their role in angiogenesis-dependent diseases are reviewed. Studies indicate that angiogenesis suppression is exerted through several mechanisms; however, further investigations are required to elucidate their precise molecular and cellular mechanisms, as well as potential side effects.

Halofuginone suppresses growth of human uterine leiomyoma cells in a mouse xenograft model

STUDY QUESTION

Does halofuginone (HF) inhibit the growth of human uterine leiomyoma cells in a mouse xenograft model?

SUMMARY ANSWER

HF suppresses the growth of human uterine leiomyoma cells in a mouse xenograft model through inhibiting cell proliferation and inducing apoptosis.

WHAT IS KNOWN ALREADY

Uterine leiomyomas are the most common benign tumors of the female reproductive tract. HF can suppress the growth of human uterine leiomyoma cells in vitro. The mouse xenograft model reflects the characteristics of human leiomyomas.

STUDY DESIGN, SIZE, DURATION

Primary leiomyoma smooth muscle cells from eight patients were xenografted under the renal capsule of adult, ovariectomized NOD-scid IL2Rγ(null) mice (NSG). Mice were treated with two different doses of HF or vehicle for 4 weeks with six to eight mice per group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Mouse body weight measurements and immunohistochemical analysis of body organs were carried out to assess the safety of HF treatment. Xenografted tumors were measured and analyzed for cellular and molecular changes induced by HF. Ovarian steroid hormone receptors were evaluated for possible modulation by HF.

MAIN RESULTS AND THE ROLE OF CHANCE

Treatment of mice carrying human UL xenografts with HF at 0.25 or 0.50 mg/kg body weight for 4 weeks resulted in a 35-40% (P < 0.05) reduction in tumor volume. The HF-induced volume reduction was accompanied by increased apoptosis and decreased cell proliferation. In contrast, there was no significant change in the collagen content either at the transcript or protein level between UL xenografts in control and HF groups. HF treatment did not change the expression level of ovarian steroid hormone receptors. No adverse pathological effects were observed in other tissues from mice undergoing treatment at these doses.

LIMITATIONS, REASONS FOR CAUTION

While this study did test the effects of HF on human leiomyoma cells in an in vivo model, HF was administered to mice whose tolerance and metabolism of the drug may differ from that in humans. Also, the longer term effects of HF treatment are yet unclear.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study showing the effectiveness of HF in reducing UL tumor growth by interfering with the main cellular processes regulating cell proliferation and apoptosis are in agreement with previous studies on the effects of HF on other fibrotic diseases. HF can be considered as a candidate for reducing the size of leiomyomas, particularly prior to surgery.

STUDY FUNDING/COMPETING INTERESTS

This project was funded by NIH PO1HD057877 and R01 HD064402. Authors report no competing interests.

Inhibition of TGF-β signaling with halofuginone can enhance the antitumor effect of irradiation in Lewis lung cancer

Purpose

It was reported that halofuginone has inhibitory effects on transforming growth factor-beta (TGF-β) signaling pathway. The study was aimed to: 1) evaluate the antitumor effects of halofuginone in combination with radiation therapy; and 2) preliminarily explore the possible mechanisms associated with these effects.

Materials and methods

Lewis lung cancer (LLC) cell lines and xenograft model mice randomly received ionizing radiation, halofuginone, or combination treatment. The changes associated with antitumor effect of halofuginone, including hepatic and pulmonary metastases and survival, were observed. The migratory and invasive capabilities of LLC cells were investigated by using scratch assay and transwell chamber assay. The expression level of TGF-β and its activation were assessed with enzyme-linked immunosorbent assay, immunohistochemistry, and Western blotting. Chi-square test and survival analysis were performed for statistical analysis. P<0.05 was regarded as statistically significant. Unless otherwise specified, data were expressed as mean ± standard deviation (x¯±s).

Results

After irradiation, the migratory and invasive capabilities of LLC cells were strengthened, and the TGF-β pathway was activated. The addition of halofuginone can significantly inhibit the migratory and invasive trend induced by irradiation, and the TGF-β pathway was also inhibited. In animal xenograft model, the addition of halofuginone to irradiation inhibited the growth of subcutaneously implanted xenografts, reduced hepatic and pulmonary metastases, and improved survival of the mice. The effect was accompanied by a decrease in TGF-β levels. In addition, halofuginone inhibited type I collagen expression and angiopoiesis.

Conclusion

Halofuginone treatment not only produces significant radiation-sensitizing effects but also inhibits hepatic and pulmonary metastases. The underlying mechanisms of these phenomena warrant additional studies.

Halofuginone inhibits phosphorylation of SMAD-2 reducing angiogenesis and leukemia burden in an acute promyelocytic leukemia mouse model

Background

Halofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models. Based on the fact that high levels of Vascular Endothelial Growth Factor (VEGF) and increased angiogenesis have been described in acute myeloid leukemia and associated with disease progression, we studied the in vivo effects of HF using an Acute Promyelocytic Leukemia (APL) mouse model.

Methods

NOD/SCID mice were transplanted with leukemic cells from hCG-PML/RARA transgenic mice (TM) and treated with HF 150 μg/kg/day for 21 days. The leukemic infiltration and the percentage of VEGF+ cells were evaluated by morphology and flow cytometry. The effect of HF on the gene expression of several pro- and antiangiogenic factors, phosphorylation of SMAD2 and VEGF secretion was assessed in vitro using NB4 and HUVEC cells.

Results

HF treatment resulted in hematological remission with decreased accumulation of immature cell and lower amounts of VEGF in BM of leukemic mice. In vitro, HF modulated gene expression of several pro- and antiangiogenic factors, reduced VEGF secretion and phosphorylation of SMAD2, blocking TGF-β-signaling.

Conclusion

Taken together, our results demonstrate that HF inhibits SMAD2 signaling and reduces leukemia growth and angiogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0181-2) contains supplementary material, which is available to authorized users.