ABSTRACT
Millions of people die from cancer every year.Because of its extremely complex etiology, humans still cannot he completely cured.In the war against cancer, bacteria effectively inhibit the growth of tumor cells, so it shows the potential as a tumor therapy.Compared with traditional chemotherapy methods, tumor-targeting bacteria have the ability to specifically colonize the tumor microenvironment, which greatly avoids the damage to normal tissues in cancer treatment, and improves the targeting and safety of treatment.At the same time, the development of synthetic biology has expanded the toolbox to optimize the lethality of bacteria to tumor by expressing protein effectors.Therefore, the gene circuit in human probiotic E.coli Nissle 1917 (EcN) is modified to make it " intelligent" , so as to optimize the method of using bacteria to treat cancer.This paper mainly reviews the history of using bacteria to treat cancer, highlights the methods of engineering EcN by synthetic biology, discusses the safety, efficiency and controllability of genetically modified live bacteria, and looks forward to the future development of bacteria in the treatment of cancer under the guidance of synthetic biology.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the feasibility of preparing ureteral acellular matrix (UAM) using perfusion systems.</p><p><b>METHODS</b>Using the luminal structure of the ureter, the UAM was prepared by perfusing canine ureter with SDS, TritonX-100, or both. The residual nuclei in the UAM were evaluated using HE staining, DAPI staining, DNA quantification, and agarose gel electrophoresis. The three-dimensional ultrastructure and the bioactive components were evaluated by Masson's trichrome staining, Alcian Blue staining, collagen quantification, GAG quantification, scanning electron microscopy (SEM), and toxicity detection.</p><p><b>RESULTS</b>HE staining and DAPI staining showed the absence of obvious nuclear materials in the combined group, which was further confirmed by DNA quantification and agarose gel electrophoresis. Masson's trichrome staining, Alcian Blue staining, collagen quantification and GAG quantification all verified that the ultrastructure and the bioactive components were well preserved in the combined group. SEM showed a large amount of porous structure on the surface of the UAM prepared by combined perfusion, and toxicity assay confirmed that the prepared UAM was nontoxic.</p><p><b>CONCLUSION</b>Perfusion of canine ureter with SDS and TritonX-100 is feasible to prepare UAM for ureteral reconstruction.</p>