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Pharm Res. 2016 Sep;33(9):2218-2228. doi: 10.1007/s11095-016-1959-4. Epub 2016 Jun 1.

Preparation and Characterization of Gelonin-Melittin Fusion Biotoxin for Synergistically Enhanced Anti-Tumor Activity.

Shin MC#1,2, Min KA#1,2,3, Cheong H4, Moon C5, Huang Y6, He H7, Yang VC2,7.

Author information

1
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, 501 Jinju Daero, Jinju, Gyeongnam, 52828, Republic of Korea.
2
Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church St., Ann Arbor, MI 48109, USA.
3
College of Pharmacy, Inje University, 197 Injero, Gimhae, Gyeongnam, 50834, Republic of Korea.
4
Comparative Biomedicine Research Branch, Division of Cancer Biology, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang, Gyeonggi-do, 10408, Republic of Korea.
5
College of Pharmacy, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam 57922, Republic of Korea.
6
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Hai-ke Rd., Shanghai 201203, China.
7
Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnosis, School of Pharmacy, Tianjin Medical University, Tianjin 300070, China.
#
Contributed equally

Abstract

PURPOSE:

To investigate the applicability of fusion biotoxins combining pore-forming toxins (PFTs) and ribosome-inactivating proteins (RIPs) for the anti-cancer treatment.

METHODS:

Membrane active PFTs tend to destabilize cell membranes of tumor cells, but lack a warhead inducing significant cause of cell death. Cell-impermeable RIPs possess a powerful warhead, yet not able to enter the tumor cells. To address these challenges for anti-tumor effects, we introduced a fusion strategy of conjugating melittin (a PFT) and gelonin (a type 1 RIP) via chemical and recombinant methods, followed by in vitro assays and in vivo animal studies.

RESULTS:

In vitro characterization results confirmed that the chimeric gelonin-melittin fusion proteins retained equivalent intrinsic activity to that of unmodified gelonin in inhibiting protein translation. However, chemically conjugated gelonin-melittin (cGel-Mel) and recombinant chimeric gelonin-melittin fusion (rGel-Mel) exhibited greater cell uptake, yielding a significantly enhanced cytotoxic activity over treatment of gelonin, melittin or physical mixture of gelonin and melittin. Remarkably, cGel-Mel and rGel-Mel displayed 32- and 10-fold lower IC50 than gelonin in the cell lines. The superior anti-tumor efficacy of multivalent cGel-Mel to monovalent rGel-Mel suggested that valency could be a crucial factor for the extent of melittin-mediated cell uptake. Tumoricidal effects observed from animal studies were in good accordance with our findings from the cellular assays.

CONCLUSIONS:

This study successfully demonstrated that fusion of biotoxins could provide a simple yet effective way to synergistically augment their anti-tumor activity.

KEYWORDS:

cancer; gelonin; melittin; ribosome inactivating protein; toxin

PMID:
27251414
PMCID:
PMC4967393
DOI:
10.1007/s11095-016-1959-4
[Indexed for MEDLINE]
Free PMC Article

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