BMC Biotechnol. 2016 Sep 1;16(1):65. doi: 10.1186/s12896-016-0294-5.

Design, purification and assessment of GRP78 binding peptide-linked Subunit A of Subtilase cytotoxic for targeting cancer cells.

Zhang L1,2, Li Z1, Shi T1, La X1, Li H3, Li Z4,5.

Author information

1Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan, 030006, China.2School of Life Science, Shanxi University, Taiyuan, 030006, China.3School of Life Science, Shanxi University, Taiyuan, 030006, China. lhq922@hotmail.com.4Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan, 030006, China. lzy@sxu.edu.cn.5College of Life Science, Zhejiang Chinese Medical University, Hangzhou, 310053, China. lzy@sxu.edu.cn.

Abstract

BACKGROUND:

Targeted therapies for cancer, especially the malignant cancer, are always restricted by the deficiency of tumor-specific drug delivery methods. Subtilase cytotoxic is a virulent cytotoxin, and the subunit A (SubA) of it is able to destroy the structure of glucose-regulated protein 78 (GRP78) to induce cell apoptosis, and to be expected as anti-cancer drugs, however, the ubiquitous receptor of subunit B of Subtilase cytotoxic (SubB) restricts its application on cancer therapy.

RESULTS:

The present study constructed and expressed a fusion protein of GBP-SubA in E. coli Rosetta (DE3) system, in which the subunit B of Subtilase cytotoxic was replaced by GRP78 binding peptide (GBP). The fusion protein was expressed in inclusion body form. Subsequently, the denaturation/renaturation process and Ni-column purification were performed. Our data indicated the purified GBP-SubA could bind GRP78 existed on cancer cell surface specifically, internalize into cells to inactivate intracellular GRP78 and induce apoptosis. Moreover, the apoptosis induction effect of GBP-SubA was enhanced obviously along with the increased cancer cell surface GBP78.

CONCLUSIONS:

It indicates that the recombinant GBP-SubA possesses the dual functions of GBP and SubA to induce cancer cell apoptosis specifically, revealing that GBP-SubA holds important implications for developing as an anti-cancer peptide drug. A schematic representation of the construction and function of GBP-SubA.

KEYWORDS:

Apoptosis; Cancer; GRP78 binding peptide; Glucose-regulated protein 78; Subunit A of Subtilase cytotoxic

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