Molecularly engineered tumor acidity-responsive plant toxin gelonin for safe and efficient cancer therapy.
1区 · 材料科学
作者: Guo-Bin Ding ; Chenchen Zhu ; Qian Wang ; Huiyan Cao ; Bin-Chun Li ; Peng Yang ; Roland H Stauber ; Guangjun Nie ; Zhuoyu Li
Due to the unsatisfactory therapeutic efficacy and inexorable side effects of small molecule antineoplastic agents, extensive efforts have been devoted to the development of more potent macromolecular agents with high specificity. Gelonin is a plant-derived protein toxin that exhibits robust antitumor effect via inactivating ribosomes and inhibiting protein synthesis. Nonetheless, its poor internalization ability to tumor cells has compromised the therapeutic promise of gelonin. In this study, a tumor acidity-responsive intracellular protein delivery system ─ functional gelonin (Trx-pHLIP-Gelonin, TpG) composed of a thioredoxin (Trx) tag, a pH low insertion peptide (pHLIP) and gelonin, was designed and obtained by genetic recombination technique for the first time. TpG could effectively enter into tumor cells under weakly acidic conditions and markedly suppress tumor cell proliferation via triggering cell apoptosis and inhibiting protein synthesis. Most importantly, treatment by intravenous injection into subcutaneous SKOV3 solid tumors in a mouse model showed that TpG was much more effective than gelonin in curtailing tumor growth rates with negligible toxicity. Collectively, our present work suggests that the tumor acidity-targeted delivery manner endowed by pHLIP offers a new avenue for efficient delivery of other bioactive substances to acidic diseased tissues.
2022-08-05·Molecular cancer therapeutics
Transient Inhibition of Trastuzumab-Tumor Binding to Overcome the "Binding-Site Barrier" and Improve the Efficacy of a Trastuzumab-Gelonin Immunotoxin.
作者: Ping Chen ; Brandon M Bordeau ; Yu Zhang ; Joseph P Balthasar
We have recently shown that co-administration of monoclonal antibodies (mAb) with anti-idiotypic distribution enhancers (AIDEs) that inhibit mAb binding to tumor antigens enabled increased intra-tumoral mAb distribution and increased efficacy of an antibody-drug conjugate (trastuzumab emtansine, T-DM1). In the present work, a PK/PD model was applied to predict the impact of this optimization strategy on the within-tumor distribution and anti-tumor efficacy of trastuzumab-gelonin, where the released payload (gelonin) is expected to exhibit negligible bystander activity. Immunofluorescence histology was used to investigate trastuzumab-gelonin distribution in solid tumors following dosing with or without co-administration of anti-trastuzumab AIDEs. Anti-tumor efficacy of trastuzumab-gelonin, with or without co-administration of AIDEs, was also evaluated in tumor-bearing mice. Trastuzumab-gelonin efficiently induced cytotoxicity when applied to NCI-N87 cells in culture (IC50: 0.224±0.079 nM). PK/PD simulations predicted that anti-idiotypic single-domain antibodies AIDEs with dissociation rate constants between 0.03-0.2 hour-1 would provide optimal enhancement of trastuzumab-gelonin efficacy. LE8 and 1HE, anti-trastuzumab AIDEs, were selected for evaluation in vivo. Co-administration of trastuzumab-gelonin with the inhibitors increased the portion of tumor area that stained positive for trastuzumab-gelonin by 58% (p=0.0059). Additionally, LE8 or 1HE co-administration improved trastuzumab-gelonin efficacy in NCI-N87 xenograft bearing mice by increasing the percent increase in life span (%ILS) from 27.8% (for trastuzumab-gelonin administered alone) to 62.5% when administered with LE8 (p=0.0007) or 83.3% (p=0.0007) when administered with 1HE. These findings support the hypothesis that transient, competitive inhibition of mAb-tumor binding can improve the intra-tumoral distribution and efficacy of immunotoxins when applied for treatment of solid tumors.
2022-03-25·The AAPS journal3区 · 医学
Targeted Delivery of Endosomal Escape Peptides to Enhance Immunotoxin Potency and Anti-cancer Efficacy.
3区 · 医学
作者: Joseph Ryan Polli ; Ping Chen ; Brandon M Bordeau ; Joseph P Balthasar
This work describes use of anti-carcinoembryonic antigen antibodies (10H6, T84.66) for targeted delivery of an endosomal escape peptide (H6CM18) and gelonin, a type I ribosome inactivating protein. The viability of colorectal cancer cells (LS174T, LoVo) was assessed following treatment with gelonin or gelonin immunotoxins, with or without co-treatment with T84.66-H6CM18. Fluorescent microscopy was used to visualize the escape of immunoconjugates from endosomes of treated cells, and efficacy and toxicity were assessed in vivo in xenograft tumor-bearing mice following single- and multiple-dose regimens. Application of 25 pM T84.66-H6CM18 combined with T84.66-gelonin increased gelonin potency by ~ 1,000-fold and by ~ 6,000-fold in LS174T and LoVo cells. Intravenous 10H6-gelonin at 1.0 mg/kg was well tolerated by LS174T tumor-bearing mice, while 10 and 25 mg/kg doses led to signs of toxicity. Single-dose administration of PBS, gelonin conjugated to T84.66 or 10H6, T84.66-H6CM18, or gelonin immunotoxins co-administered with T84.66-H6CM18 were evaluated. The combinations of T84.66-gelonin + 1.0 mg/kg T84.66-H6CM18 and 10H6-gelonin + 0.1 mg/kg T84.66-H6CM18 led to significant delays in LS174T growth. Use of a multiple-dose regimen allowed further anti-tumor effects, significantly extending median survival time by 33% and by 69%, for mice receiving 1 mg/kg 10H6-gelonin + 0.1 mg/kg T84.66-H6CM18 (p = 0.0072) and 1 mg/kg 10H6-gelonin + 1 mg/kg T84.66-H6CM18 (p = 0.0017). Combined administration of gelonin immunoconjugates with antibody-targeted endosomal escape peptides increased the delivery of gelonin to the cytoplasm of targeted cells, increased gelonin cell killing in vitro by 1,000-6,000 fold, and significantly increased in vivo efficacy.