Abstract
Investigate whether rAAV‐anginex gene therapy combined with radiotherapy could decrease growth and pulmonary metastasis of osteosarcoma in mice and examine the mechanisms involved in this therapeutic strategy. During in vitro experiment, multiple treatment regimes (rAAV‐eGFP, radiotherapy, rAAV‐anginex, combination therapy) were applied to determine effects on proliferation of endothelial cells (ECs) and G‐292 osteosarcoma cells. During in vivo analysis, the same multiple treatment regimes were applied to osteosarcoma tumor‐bearing mice. Use microcomputed tomography to evaluate tumor size. Eight weeks after tumor cell inoculation, immunohistochemistry was used to assess the therapeutic efficacy according to microvessel density (MVD), proliferating cell nuclear antigen (PCNA), and terminal‐deoxynucleotidyl transferase‐mediated nick‐end labeling (TUNEL) assays. Metastasis of lungs was also evaluated by measuring number of metastatic nodules and wet weight of metastases. The proliferation of ECs and the tumor volumes in combination therapy group were inhibited more effectively than the other three groups at end point (P < 0.05). Cell clone assay showed anginex had radiosensitization effect on ECs. Immunohistochemistry showed tumors from mice treated with combination therapy exhibited the lowest MVD and proliferation rate, with highest apoptosis rate, as confirmed by IHC staining for CD34 and PCNA and TUNEL assays (P < 0.05). Combination therapy also induced the fewest metastatic nodules and lowest wet weights of the lungs (P < 0.05). rAAV‐anginex combined with radiotherapy induced apoptosis of osteosarcoma cells and inhibited tumor growth and pulmonary metastasis on the experimental osteosarcoma models. We conclude that the primary mechanism of this process may be due to sensitizing effect of anginex to radiotherapy.
Highlights
Osteosarcoma is the most common primary malignant tumor of the bone and has a high incidence in children and adolescents
This study investigated the inhibitory effects of anginex on an in vivo osteosarcoma model using severe combined immunodeficient (SCID) mice and the effects of a combination therapy with radiotherapy
McCoy’s 5a medium, RPMI 1640, phosphate-buffered saline (PBS), fetal bovine serum (FBS), and 0.25% trypsin were purchased from Gibco BRL (Life Technologies, Inc, Rockville, MD). 3-(4,5-Dimethylthiazol-2-yl)-2,5-dipheny ltetrazolium bromide (MTT) reagent was purchased from BD Biosciences (Bedford, MA)
Summary
Osteosarcoma is the most common primary malignant tumor of the bone and has a high incidence in children and adolescents. The mechanism is still controversial, some researchers have proposed the “vascular normalization theory” [13], in which more efficient delivery of drugs and oxygen to the targeted cancer cells is achieved through the modified vessels following treatment with anti-angiogenic agents [14]. This would make the cancer cells more sensitive to radiotherapy and chemotherapy, thereby increasing the efficacy of treatment. Our results demonstrated that anginex combined therapy exhibited strong inhibition of tumor blood vessels and the growth and metastasis of the tumor itself, making it a promising agent with potential applications in the treatment of osteosarcoma
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
