Detection of tumor cell apoptosis in vivo with 99mTc-HYNIC-annexin V after a single dose of radiotherapy / 中国肿瘤临床

ABSTRACT

Objective:The aims of this study are to detect the apoptosis of cancer cells after a single dose of radiotherapy with 99mTc-HYNIC-annexin V and to investigate the correlation among early apoptosis, radio-therapeutic dose, and radio-sensitivity. Methods:Ten days after respective inoculations of EL4 lymphoma and S180 sarcoma in their right upper limbs, the mice were randomly divided into imaging group (Group One) and observation group (Group Two). In Group One, 99mTc-HYNIC-annexin V was injected via the caudal vein after different doses of irradiation. Approximately 2 h later, clinical imaging was conducted by single-photon emission-computed tomography. The mice were sacrificed to evaluate the bio-distribution of 99mTc in each specimen. Cell count during apoptosis was conducted through the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. Observation was conducted in Group Two for 2 weeks after the irradiation. Results:Tumor uptake of 99mTc-HYNIC-annexin V significantly correlated with the number of TUNEL-positive cells, which concordantly increased with the increase of dosage (r=0.892, P=0.000). With the same dose (0 or 8 Gy), the values of%ID/g, T/B, T/M, and TUNEL-positive cell number of EL4 lymphoma were significantly higher compared with those of S180 sarcoma. EL4 lymphoma was entirely minimized after irradiation at 8 Gy. Conclusion: 99mTc-HYNIC-annexin V can detect early apoptosis in vivo in tumors receiving radiation. The irradiation-induced apoptosis in vivo determined with 99mTc-HYNIC-annexin V positively correlates with the curative effect of tumors. The detection of tumor cell apoptosis via 99mTc-HYNIC-annexin V helps estimate radio-sensitivity, and can become a predictive index for radiotherapy.