Bifidobacteria Expressing Tumstatin Protein for Antitumor Therapy in Tumor-Bearing Mice

Abstract

Tumstatin (Tum) is a powerful angiostatin that inhibits proliferation and induces apoptosis of tumorous vascular endothelial cells. A nonpathogenic and anaerobic bacterium, Bifidobacterium longum (BL), selectively localizes to and proliferates in the hypoxia location within solid tumor. The aims of this study were to develop a novel delivery system for Tum using engineered Bifidobacterium and to investigate the inhibitory effect of Tum on tumor in mice. A vector that enabled the expression of Tum under the control of the pBBADs promoter of BL was constructed and transformed into BL NCC2705 by electroporation. The mouse colon carcinoma cells CT26 (1 × 10(7)/mL) were subcutaneously inserted in the left armpit of BALB/c mice. The tumor-bearing mice were treated with Tum-transformed BL, and green fluorescent protein (GFP)-transformed BL was used as a negative control. The microvessel density (MVD) in the transplanted tumor was determined, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling was used to detect apoptosis of vascular endothelial cells in transplanted tumor. The in vitro expression of Tum was examined in BL after l-arabinose induction. Bifidobacterium longum with pBBAD-Tum (BL-Tum) showed significant antitumor effect in tumor-bearing mice. The weight, volume, growth, and MVD, as well as the percentage of apoptotic vascular endothelial cells of transplanted tumors in the tumor-bearing mice treated with Tum-transformed BL were all significantly lower than those in the GFP negative control group. Intragastric administration, injection in tumor and vena caudalis injection of Tum-transformed BL exerted marked antitumor effects in tumor-bearing mice. This is the first demonstration of the utilization of Tum-transformed BL as a specific gene delivery system for treating tumor.

Developing a new class of engineered live bacterial therapeutics to treat human diseases

“…Co-administration of a CD-expressing Bifidobacterium infantis strain with 5-FC significantly inhibited tumor growth in mice 67 . In a similar study, Wei et al engineered Bifidobacterium longum to express the proapoptotic compound, tumstatin 68 . This strain was shown to inhibit tumor growth in a mouse model by various routes of administration 68 .…”

“…In a similar study, Wei et al engineered Bifidobacterium longum to express the proapoptotic compound, tumstatin 68 . This strain was shown to inhibit tumor growth in a mouse model by various routes of administration 68 . Given the plethora of preclinical data, engineered variants of E. coli, Bifidobacterium, Salmonella, and Listeria strains are all currently being evaluated clinically for the treatment of solid tumors (Table 1).…”

Matricryptins Network with Matricellular Receptors at the Surface of Endothelial and Tumor Cells

“…Several approaches improve the delivery of matricryptins to tumors and endothelial cells (Xu et al, 2007 ; Ricard-Blum and Ballut, 2011 ) such as conditionally replicating oncolytic adenoviral vector for arresten (Li et al, 2015a ), naked plasmid electrotransfer in muscle for tumstatin overexpression (Thevenard et al, 2013 ), and the nonpathogenic and anaerobic bacterium, Bifidobacterium longum , which proliferates in the hypoxic zones within tumors for tumstatin expression (Wei et al, 2015 ). Endostatin has been delivered in polylactic acid nanoparticles (Hu and Zhang, 2010 ), in gold nanoshells, which are very efficient on lung cancer cells when associated with near-infrared thermal therapy (Luo et al, 2015 ) and into microbubbles in combination with ultrasonic radiation in a cancer model (Zhang et al, 2014 ).…”

Intravenous Administration Is an Effective and Safe Route for Cancer Gene Therapy Using the Bifidobacterium-Mediated Recombinant HSV-1 Thymidine Kinase and Ganciclovir

“…Therefore, BF is an optimal cancer gene therapy vector due to the anaerobic properties. In recent years, BF has been widely used as a cancer-targeting gene therapy vector [ 10 , 21 , 22 , 25 , 26 , 27 , 28 , 29 ].…”