The effects of methylprednisolone and halofuginone on preventing esophageal and hypopharyngeal fibrosis in delivered radiotherapy

Amelioration of radiation-induced lung injury by halofuginone: An experimental study in Wistar-Albino rats

To evaluate effects of halofuginone (H) on radiation-induced lung injury (RILI), 60 rats were divided into six groups: Group (G) 1 control, G2 radiotherapy (RT) only, G3 and G4 2. 5 and 5 μg H and G5 and G6 RT + 2.5 and 5 μg H groups, respectively. A single dose of 12 Gy RT was given to both lungs. H was applied intraperitoneally with daily doses, until animals were killed at 6 and 16 weeks after RT. At 6th and 16th weeks of RT, five rats from each group were killed. Lung tissues were dissected for light and electron microscopy. Chronic inflammation, fibrosis and transforming growth factor-beta (TGF)-β scores of all study groups were significantly different at 6th and 16th week ( p < 0.001). Chronic inflammation, fibrosis and TGF-β scores of G2 were higher than G5 and G6 at 6th and 16th weeks of RT. At 16th week, fibrosis and TGF-β scores of G5 were higher than G6 ( p = 0.040 and 0.028, respectively). Electron microscopical findings also supported these results. Therefore, H may ameliorate RILI. The effect of the H was more prominent at higher dose and after long-term follow-up. These findings should be clarified with further studies.

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 for fibrosis, regeneration and cancer in the gastrointestinal tract

Organ fibrosis and architectural remodeling can severely disrupt tissue function, often with fatal consequences. Fibrosis is the end result of chronic inflammatory reactions induced by a variety of stimuli, and the key cellular mediator of fibrosis comprises the myofibroblasts which, when activated, serve as the primary collagen-producing cells. Complex links exist between fibrosis, regeneration and carcinogenesis, and the concept that all organs contain common tissue fibrosis pathways that could be potential therapeutic targets is an attractive one. Because of the major impact of fibrosis on human health there is an unmet need for safe and effective therapies that directly target fibrosis. Halofuginone inhibits tissue fibrosis and regeneration, and thereby affects the development of tumors in various tissues along the gastrointestinal tract. The high efficacy of halofuginone in reducing the fibrosis that affects tumor growth and tissue regeneration is probably due to its dual role in inhibiting the signaling pathway of transforming growth factor β, on the one hand, and inhibiting the development of Th17 cells, on the other hand. At present halofuginone is being evaluated in a clinical trial for other fibrotic indication, and any clinical success in that trial would allow the use of halofuginone, also for all other fibrotic indications, including those of the gastrointestinal tract.

Preliminary results of antiscarring therapy in the prevention of postendoscopic esophageal mucosectomy strictures

BACKGROUND

Esophageal endoscopic submucosal dissection (ESD) is an effective minimally invasive therapy for early esophageal cancer and high-grade Barrett dysplasia. However, esophageal stricture formation after circumferential or large ESD has limited its wide adoption. Mitomycin C (MMC), halofuginone (Hal), and transforming growth factor β3 (TGF-β3) exhibits antiscarring effects that may prevent post-ESD stricture formation.

METHODS

Using endoscopic mucosectomy (EEM) technique, an 8- to 10-cm-long circumferential esophageal mucosal segment was excised in a porcine model. The site was either untreated (control, n = 6) or received 40 evenly distributed injections of antiscarring agent immediately and at weeks 1 and 2. High and low doses were used: MMC 5 mg (n = 2), 0.5 mg (n = 2); Hal 5 mg (n = 2), 1.5 mg (n = 2), 0.5 mg (n = 2); TGF-β3 2 μg (n = 2), 0.5 μg (n = 2). The degree of stricture formation was determined by the percentage reduction of the esophageal lumen on weekly fluoroscopic examination. Animals were euthanized when strictures exceeded 80 % or the animals were unable to maintain weight.

RESULTS

The control group had a luminal diameter reduction of 78.2 ± 10.9 % by 2 weeks and were euthanized by week 3. Compared at 2 weeks, the Hal group showed a decrease in mean stricture formation (68.4 % low dose, 57.7 % high dose), while both TGF-β3 dosage groups showed no significant change (65.3 % low dose, 76.2 % high dose). MMC was most effective in stricture prevention (53.6 % low dose, 35 % high dose). Of concern, the esophageal wall treated with high-dose MMC appeared to be necrotic and eventually led to perforation. In contrast, low dose MMC, TGF-β3 and Hal treated areas appeared re-epithelialized and healthy.

CONCLUSIONS

Preliminary data on MMC and Hal demonstrated promise in reducing esophageal stricture formation after EEM. More animal data are needed to perform adequate statistical analysis in order to determine overall efficacy of antiscarring therapy.

The effect of Halofuginone in the amelioration of radiation induced-lung fibrosis

The lung is one of the most sensitive organs to ionizing radiation, and damage to normal lung tissue remains a major dose limiting factor for patients receiving radiation to the thorax. Radiation induced lung injury (RILI) which is also named as "radiation pneumonpathy" is a continuous process and regarded as the result of an abnormal healing response. It has been shown that transforming growth factor β-1 (TGF-β1) plays an integral role in the radiation induced lung fibrosis formation by promoting the chemoattraction of fibroblasts and their conversion to myofibroblasts. Halofuginone is a, low molecular weight plant derived alkaloid, isolated from the Dichroa febrifuga plant that exhibits antifibrotic activity and inhibition of type I collagen synthesis. Halofuginone has been shown to protect against radiation induced soft tissue fibrosis by virtue of inhibiting various members of TFG-β signaling pathway. By the light of these findings, we hypothesize that Halofuginone may be able to ameliorate the radiation induced lung fibrosis.