Our designed BioBricks containing the gene for the mature region of mouse Bone Morphogenetic Protein 2 (BMP2) all possess a level of risk. As a mammalian biochemical agent, it is known to elicit a wide variety of biological effect on human tissue organs, of which the most well known are bone and cardiac cell differentiation induction. However, as a defining member of the Transforming Growth Factor Beta (TGF-β) pathway, it also plays important roles in cell proliferation. Thus, induction of excess (or otherwise external) BMP2 may lead to undesirable tissue behavior in mammalian systems.

Documented adverse effects of recombinant human BMP2 used in spinal fusion therapy include cyst-like bony formations and soft swelling with hematomas. Further research using mice with spine defects as test subjects indicates that occurrence and severity of said adverse effects increases with BMP2 dosage. Though we have selected BMP2 for its documented properties of retarding the growth of and induction of cell death in colon carcinoma cells, BMP2 receptor transcription has been found up-regulated in other cancer cell types, including pancreatic cancer. Thus, confined delivery of the chemokine becomes critical.

See relevant documents by following links below:
High Doses of Bone Morphogenetic Protein 2 Induce Structurally Abnormal Bone and Inflammation In Vivo
Bone morphogenetic protein signaling and growth suppression in colon cancer

We highly recommend that future teams intending to use this gene simultaneously incorporate methods to control production of BMP2 to minimize its release into the environment or contact with researchers and the public. Our strategy described in module 3 – ‘control and regulation system’ may be taken as an initial attempt to achieve this.

BioBricks for expression of the lytC protein cell wall binding domain with the RPMrel phage display peptide attached at its C-terminus results in RPMrel peptides anchored to the chassis cell wall. It is known that phages displaying this peptide bind preferentially to the highly tumorigenic HT29 colorectal cell line by at least 10-fold higher than the less tumorigenic HCT116 colorectal cell line. As expression of this peptide in bacterial cells is novel, steps should be taken to minimize the chance of its horizontal transfer to pathogenic bacterial species, which could result in increased infection activity of that species. Integration of this gene into the bacterial genome, an approach taken by our team, would be one way to work towards reducing horizontal gene transfer.

Please refer to the document below:
Isolation of a Colon Tumor Specific Binding Peptide Using Phage Display Selection

Elements of our toxin-antitoxin system for control over cell lysis comprise the ydcDE operon of Bacillus subtilis. The ydcE gene encodes an endoribonuclease targeting regular regions of cellular mRNA. The gene ydcD has been shown to inhibit the function of said endonuclease in vivo. Our system employs those same gene products recombined with different promoters: pVeg promoter for ydcD, pXyl promoter for ydcE. An investigation to determine whether expression of the E. coli ydcE homolog (mazF) in macaque monkeys is safe yielded results indicating an absence of tissue damage and antigen-specific antibody production. We therefore consider the ydcE product to be non-toxic to humans.

Again refer to the document by clicking here.