Cervical cancer caused by
infection with high-risk human papillomavirus remains to be the most deadly gynecologic
malignancy worldwide. It is well documented that persistent expression of two oncogenes (E6/E7) plays the key roles in
cervical cancer. Thus, in vivo detection of the
oncoproteins is very important for the diagnosis of the
cancer. Recently, affibody molecules have been demonstrated to be a powerful targeting probe for
tumor-targeted imaging and diagnosis. In this study, four HPV16 E7-binding affibody molecules (Z HPV16 E7127, Z HPV16E7301, Z HPV16E7384 and Z HPV16E7745) were screened from a phage-displayed
peptide library and used for molecular imaging in
tumor-bearing mice. Biosensor binding analyses showed first that the four affibody molecules bound to HPV16 E7 with very high affinity and specificity. They co-localized with E7
protein only in two HPV16-positive
cancer cells (SiHa and CaSki). Furthermore, affibody ZHPV16E7384 was conjugated with Dylight755 and used for in vivo
tumor-imaging. Strongly high-contrast
tumor retention of this affibody only occurred in HPV16-derived
tumors of mice as early as 30 min post-injection, not in HPV-negative and HPV18-derived
tumors. The accumulation of Dylight755-conjugated ZHPV16E7384 in
tumor was achieved over a longer time period (24 h). The data here provide strong evidence that E7-specific affibody molecules have great potential used for molecular imaging and diagnosis of HPV-induced
cancers.