Targeting, imaging and treating of colorectal cancer with safe theranostic bacteria




01. July 2018 - 30. June 2021


0,17 FTE


Janko Kos


4.06 Biotechnical sciences / Biotechnology

Research Organisation:







The aim of the proposed project is to develop safe theranostic lactic acid bacteria (ProbioTheranostics) that will be engineered with the ability to specifically target colorectal cancer cells, localize the tumor position using fluorescence imaging, and treat the colorectal cancer by exerting anti-inflammatory activity and modulating the composition of microbiota. ProbioTheranostics will be administered locally via oral route and will be tested in cell and animal colorectal cancer models. Colorectal cancer is the third most common cancer in the world with 1.2 million cases reported every year and increasing incidence. It therefore represents a heavy burden for the health system. Current treatment approaches (chemotherapy, surgery and monoclonal antibodies) have limited efficiency and severe side effects; researchers are therefore constantly looking for better treatment options. New approaches focus on the reduction of side effects, targeted therapy, combination therapy and concomitant therapy and diagnostics (theranostics). Immune system and intestinal microbiota are important factors in colorectal cancer. Immune cells play a role in tumor prevention, as well as in the progression of tumor development. A change in the composition of microbiota (dysbiosis) is a characteristic of colorectal cancer and contributes to its progression. Supplementation with probiotics from the group of lactic acid bacteria can influence the immune system and modulate microbiota composition. Apart from using wild-type beneficial probiotic bacteria they can also be genetically engineered to express recombinant proteins that provide additional therapeutic benefit. This approach was successfully demonstrated in the treatment of inflammatory bowel disease and, to a limited extent, in the treatment of colorectal cancer. Our research group has significant experience with genetic engineering of lactic acid bacteria and their testing in animal models that will serve as a foundation for the proposed project. We have prepared recombinant L. lactis with TNFα neutralizing ability. We have developed a new approach to coat unmodified lactic acid bacteria with protein binders. Additionally, we have demonstrated the expression of infrared fluorescent protein in lactic acid bacteria and thereby enabled in vivo imaging and tracking. In the proposed project we intend to develop supporting genetic engineering techniques for lactic acid bacteria that will enable inducible expression of multiple proteins and genome integration using CRISPR-Cas technique. Lactic acid bacteria will be used to express proteins for targeting of cancer surface antigens, protein that enables in vivo imaging, and proteins that will provide therapeutic benefit by neutralizing pro-inflammatory cytokines. Multiple protein moieties will be combined in a single bacterial species by multiple protein expression and heterologous protein coating. This will result in the engineering of theranostic bacterial species that will combine targeting, imaging and therapeutic properties. Additional engineering will be performed to establish regulatory acceptance and stability of theranostic bacteria. We will test the developed bacteria in cell line models in collaboration with Prof. Janko Kos from the Faculty of Pharmacy, who is an expert in cancer biology. Additionally, we will test the in vivo therapeutic efficacy and imaging-based diagnostics in a mouse model with chemically-induced colorectal cancer. The intrinsic efficacy of modified and unmodified probiotic bacteria on microbiota modulation will be evaluated with next generation sequencing. Our proposal represents a completely new concept for the use of safe engineered bacteria that could lead to the discovery of novel adjuvant therapeutic and diagnostic method for colorectal cancer. The complementary combination of experienced scientists and realistic project schedule speak in favor of the feasibility of the project.



Bibliographical references, arising directly from the implementation of the project:


Financed by:

Research projects (co)funded by the Slovenian Research Agency.