Pharmacokinetics of HM-3 After Intravitreal Administration in Mice

The Protective Effect of a Long-Acting and Multi-Target HM-3-Fc Fusion Protein in Rheumatoid Arthritis

Current treatment of rheumatoid arthritis (RA) is limited by relative shortage of treatment targets. HM-3 is a novel anti-RA polypeptide consisting of 18 amino acids with integrin αVβ3 and α5β1 as targets. Previous studies confirmed that HM-3 effectively inhibited the synovial angiogenesis and the inflammatory response. However, due to its short half-life, the anti-RA activity was achieved by frequent administration. To extend the half-life of HM-3, we designed a fusion protein with name HM-3-Fc, by combination of modified Fc segment of immunoglobulin 4 (IgG4) with HM-3 polypeptide. In vitro cell experiments demonstrated that HM-3-Fc inhibited the proliferation of splenic lymphocytes and reduced the release of TNF-α from macrophages. The pharmacodynamics studies on mice paw in Collagen-Induced Arthritis (CIA) model demonstrated that HM-3-Fc administered once in 5 days in the 50 and 25 mg/kg groups, or once in 7 days in the 25 mg/kg group showed a better protective effect within two weeks than the positive control adalimumab and HM-3 group. Preliminary pharmacokinetic studies in cynomolgus confirmed that the in vivo half-life of HM-3-Fc was 15.24 h in comparison with 1.32 min that of HM-3, which demonstrated that an Fc fusion can effectively increase the half-life of HM-3 and make it possible for further reduction of subcutaneous injection frequency. Fc-HM-3 is a long-acting active molecule for RA treatment.

An integrin αvβ3 antagonistic modified peptide inhibits tumor growth through inhibition of the ERK and AKT signaling pathways

HM-3, an RGD (Arg-Gly-Asp)-modified antitumor polypeptide designed independently, has been demonstrated for its robust inhibitory effects on tumors. However, the intravenous administration and short half-life in vivo are inconvenient to its clinical application. To solve these issues, PEGylated HM-3 (mPEG-SC20k-HM-3) with prolonged half‑time in vivo and subcutaneous administration was obtained after repeated screening of different types of PEG and numerous efficacy assays. The present study aimed to evaluate the antitumor activity and investigate the mechanism of the modified peptide to interpret the antitumor properties of mPEG-SC20k-HM-3 comprehensively and clearly. The results of the antitumor activity assays in vitro indicated that mPEG-SC20k-HM-3 exhibited a marked inhibitory activity on tumor metastasis and angiogenesis. mPEG-SC20k-HM-3 (73.4 mg/kg, sc) achieved a tumor inhibitory rate of 70.1% in an H460 (human non-small cell lung cancer) xenograft model with scarce cytotoxicity, compared with a rate of 72.2% for Avastin (10.0 mg/kg, iv). The mechanistic study showed that mPEG-SC20k-HM-3 could target integrin αvβ3 to block the downstream ERK and Akt pathways, as the expression levels of VEGF, Akt1, p-Akt1, ERK1/2, p-ERK1/2, MEK1, p-MEK1, integrin αv and β3 were reduced after HUVECs were incubated with mPEG-SC20k-HM-3 for 24 h. In conclusion, the antitumor activity of mPEG-SC20k-HM-3 in vitro and in vivo is promising and the mechanism was clearly reflected in the present study.

Tat PTD-Endostatin-RGD: A novel protein with anti-angiogenesis effect in retina via eye drops

BACKGROUND

Diabetic retinopathy is a leading cause of blindness. The objective was to design a novel fusion protein, Tat PTD-Endostatin-RGD, to treat retinal neovascularization via eye drops instead of traditional intravitreal injection trepapeutical methods.

METHOD

The anti-angiogenesis ability was evaluated in vitro by chick embryo chorioallantoic membrane assay, wound healing assay and tube formation assay. Corneal barrier and blood-retina barrier were constructed in vitro to investigate the penetration ability of Tat PTD-Endostatin-RGD. Western blot was used to detect the integrin αvβ3 expression level in rat retina microvascular endothelial cells which was stimulated by S-nitroso-N-acetylpenicillamine. The binding affinity of Tat PTD-Endostatin-RGD to integrin αvβ3 was investigated by evaluating the penetration ability on blood-retina barriers treated with S-nitroso-N-acetylpenicillamine. The pharmacodynamics and efficacy analysis were further carried out in the oxygen-induced retinopathy model in vivo. In addition, the pharmacokinetic profile via eye drops was studied on a C57BL/6 mice model.

RESULT

Tat PTD-Endostatin-RGD showed high anti-angiogenesis activity and high ability to penetrate these two barriers in vitro. The Western blot results indicated S-nitroso-N-acetylpenicillamine upregulated the expression level of integrin αvβ3 in a dose-dependent manner. Tat PTD-Endostatin-RGD showed a high affinity to rat retina microvascular endothelial cells treated with S-nitroso-N-acetylpenicillamine. The results showed that Tat PTD-Endostatin-RGD could inhibit abnormal angiogenesis in retina via eye drops.

CONCLUSION

Tat PTD-Endostatin-RGD showed high penetration ability through ocular barriers, bound specifically to integrin αvβ3 and effectively inhibited the abnormal angiogenesis.

GENERAL SIGNIFICANCE

Tat PTD-Endostatin-RGD represents a potent novel drug applied via eye drops for fundus oculi neovascularization diseases.