Tumor specific hypoxia-activated expression of cardiac peptides using an engineered subtype of Escherichia coli suppresses tumor growth, angiogenesis and metastasis in mouse model of breast cancer

Behrad Darvishi,Mitra Samadi,Ahad Mohamadnajad,Neda Jalili,Leila Farahmand,Azade Sharifkhatibi,Keivan Majidzadeh,Malihe Salehi,Shima Moradi,Marjan Mosayebzadeh,Zeinab Noorinejad

doi:10.22541/au.158636273.33390608

Abstract

Background Application of genetically modified non-pathogenic bacteria expressing specific anti-tumor proteins under certain conditions specific to tumors is an effective approach for selective targeting of tumors. We developed here, for the first time, a novel spatiotemporal cancer targeted therapy applying engineered E. coli bacteria with capability of expressing cardiac peptides under hypoxic conditions of tumor. Method E. coli BW25133 was transformed with construction of co-expressing cardiac hormones and GFP. Bacteria bearing constructs were then IV administered in mice bearing tumors and then tumor localization, as well as tumor proliferation, invasion and angiogenesis biomarkers (Ki-67, VEGFR, CD31and MMP9), changes in cytokine profile, suppression of tumor growth and survival were analyzed. Results IV Administered bacteria bearing constructs could specifically localize at tumor site and express cardiac peptides under hypoxic conditions. Administration of bacteria significantly enhanced survival rate, suppressed tumor progression and lowered expression levels of MMP-9, VEGFR2, CD31and Ki67 as potent markers for angiogenesis, tumor proliferation and metastasis. Furthermore, applied bacteria resulted in significant reduction in the expression of IL-1β, IL-6, GC-SF, IL-12 and TNF-α proinflammatory cytokines, whereas increasing IL-10, IL-17A and INF-γ cytokines. Conclusion Overall, administration of E. coli bearing cardiac hormone expression construct could effectively suppress tumor growth, angiogenesis, invasion and metastasis while enhancing survival rate in mice model of breast cancer.

Highlights

An excellent approach for spatiotemporal targeting of tumors, regardless of their origin or location, is application of genetically modified non-pathogenic anaerobic bacteria (e.g. Salmonella, E. coli, Clostridium, Bifidobacterium) which can be preferentially localized and proliferative in tumor site (Pawelek et al, 2003)
For the first time, a novel spatiotemporal cancer targeted therapy applying engineered E. coli bacteria with capability of expressing cardiac peptides under hypoxic conditions of tumor
IV Administered bacteria bearing constructs could localize at tumor site and express cardiac peptides under hypoxic conditions

Summary

Introduction

An excellent approach for spatiotemporal targeting of tumors, regardless of their origin or location, is application of genetically modified non-pathogenic anaerobic bacteria (e.g. Salmonella, E. coli, Clostridium, Bifidobacterium) which can be preferentially localized and proliferative in tumor site (Pawelek et al, 2003). Contrary to the conventional cancer therapies, bacteria can penetrate in tumor site and be engineered in a way to respond in conditions specific to the tumors (Forbes, 2010). Rendering these genera of bacteria in to non-toxic forms for human results in attenuation of their toxicity against cancer cells (Nemunaitis et al, 2003). Numerous strategies have been applied for further improving their anti-tumoral activities One such a strategy is to engineer bacteria to secret specific group of cytolytic proteins such as toxins (e.g. Staphylococcus aureus alpha hemolysin) or enzymes with capability of converting non-toxic prodrugs in to cytotoxic ones (e.g. E_coli cytosine deaminase, converting 5-Fluorocytosine in to 5-Fluorouracil) (Jean et al, 2014). For the first time, a novel spatiotemporal cancer targeted therapy applying engineered E. coli bacteria with capability of expressing cardiac peptides under hypoxic conditions of tumor

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Results

Conclusion