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
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.