Bakground Colorectal cancer (CRC) is the third most common cancer
worldwide and the second most common cause of cancer-related death.
Various molecular markers are used for early CRC diagnosis. Of these,
human ephrin receptor family type-A 2 (hEphA2) oncoprotein is
overexpressed significantly at the early, but not late, stages of CRC.
Previously, we reported an E1 monobody that is specific for
hEphA2-expressing cancer cells both in vitro and in vivo. Aim We aimed
to use E1 monobody as a detection probe for hEPhA2 expressing colorectal
cancer. In addition, we investigated the efficacy of E1 monobody to
target on human colorectal cancer tissue. Method Here, we confirmed the
expression of hEPhA2 on the surface of colorectal cancer cells by
western blotting and flow cytometry. We evaluated the targeting efficacy
of E1 monobody on colorectal cancer cells by flow cytometry and further
confirmed with immunofluorescence staining. E1 conjugated to the Rluc8
reporter protein were used as imaging agent for in vivo imaging.
Additionally, EGFP conjugated E1 monobody were used to check the
targeting ability of E1 monobody on human colorectal cancer tissue.
Result E1 bound efficiently to nine hEphA2-expressing CRC cell lines and
E1 conjugated to the Rluc8 reporter protein targeted tumor tissues in
mice transplanted with HCT115 CRC tumor cells. Finally, E1-EGFP stained
tumor tissues from human CRC patients, showing a pattern similar to that
of an anti-hEphA2 antibody. Conclusion These results suggest that the E1
monobody has utility as a probe to detect CRC.