BACKGROUND AND OBJECTIVERadiation sensitivity is closely related to tissue oxygen, and rh-endostatin can induce the high level of oxygen content in tumor by "normalizing" tumor angiogenesis which is associated with radiotherapy sensitivity. The aim of this study is to observe the effect of combination of radiotherapy with rh-endostatin in the rats with lung cancer.

METHODSImmediate lewis cancerous ascetic injection method was used to make rats tumors bearing model, then the rats was divided into four groups randomly: group A was treated with saline; group B was treated with rh-endostatin; group C was treated with irradiation and group D was treated with rh-endostatin and irradiation. After all rats were treated, inhibition rates and the tumor growth curve were calculated. Immunohistochemisty was adopted to check the expressions of vascular endothelial growth factor (VEGF) and microvessel density (MVD).

RESULTSCompared with group A, the growth rates of the tumors in the other group were obviously slower, and the tumor weights were significantly different form group A (P < 0.05). Compared with the other groups, the tumor weights of group D were obviously reduced (P < 0.05). Compared with group A, VEGF and MVD of other three groups were reduced (P < 0.05), and group D were significantly cut down.

CONCLUSIONCombination with radiotherapy and rh-endostatin could inhibit the lung cancer significantly in rats. The possible mechanisms are to decrease the expression ofVEGF and inhibit the production of angiogenesis.

Animals ; Carcinoma, Lewis Lung ; drug therapy ; metabolism ; pathology ; radiotherapy ; Endostatins ; therapeutic use ; Female ; Immunohistochemistry ; Lung Neoplasms ; drug therapy ; metabolism ; radiotherapy ; Mice ; Mice, Inbred C57BL ; Microvessels ; pathology ; Random Allocation ; Vascular Endothelial Growth Factor A ; metabolism

Honokiol is an active compound purified from magnolia that has been shown to induce cell differentiation, apoptosis, and anti-angiogenesis effects, as well as an enhancement in tumor growth delay in combination with chemotherapeutic agents in several mouse xenograft models. Our goal was to investigate the radiosensitization effect of honokiol on lung carcinoma. The radiosensitization effect of liposomal honokiol in Lewis lung carcinoma cells (LL/2) was analyzed using an in vitro clonogenic survival assay. For an in vivo study, Lewis lung carcinoma-bearing C57BL/6 mice were treated with either liposomal honokiol at 25 mg/kg or 5 Gy of single tumor radiation, or a combination of both over 12 days of treatment. The tumor growth delay and the survival time were evaluated. In addition, histological analysis of tumor sections was performed to examine changes by detecting the microvessel density and apoptosis in tumor tissues. In the clonogenic survival assay, LL/2 cells treated with IC50 Lipo-HNK for 24 h showed a radiation enhancement ratio of 1.9. After 12 days of combination treatment, the tumor volume decreased 78% and produced an anti-tumor activity 1.3-fold greater than a predicted additive effect of honokiol and radiation alone. This combination treatment also caused an 8.7 day delay in tumor growth. The cell cycle distribution and histological analysis demonstrated that liposomal honokiol has an anti-tumor effect via inducing apoptosis and inhibiting angiogenesis. Liposomal honokiol can enhance tumor cell radiosensitivity in vitro and in vivo, indicating that radiotherapy combined with liposomal honokiol can lead to greater anti-tumor efficacy.
Angiogenesis Inhibitors/administration & dosage/*therapeutic use ; Animals ; Apoptosis ; Biphenyl Compounds/administration & dosage/*therapeutic use ; Carcinoma, Lewis Lung/drug therapy/radiotherapy/*therapy ; Cell Cycle/drug effects/radiation effects ; Cell Line, Tumor ; Combined Modality Therapy ; Humans ; Lignans/administration & dosage/*therapeutic use ; Liposomes ; Lung Neoplasms/drug therapy/radiotherapy/*therapy ; Magnolia/chemistry ; Mice ; Neoplasm Transplantation ; Neovascularization, Pathologic/drug therapy/radiotherapy ; Radiation Tolerance ; Transplantation, Heterologous

OBJECTIVETo investigate the effect of mannatide injection (MI) in enhancing the efficacy of radiotherapy in two therapeutic schedules in mice bearing Lewis lung cancer.

METHODSC57BL/6 mice bearing Lewis lung cancer xenograft were assigned randomly into control group, fractionated schedule (FS) group, nonfractionated schedule (NFS) group, MI group, FS+MI group, and NFS+MI group (n=10). MI (4.5 mg/kg) or saline was given intraperitoneally for 14 consecutive days in the corresponding groups. Radiation with 8 MeV electron beam was delivered in a single 4 Gy dose in NFS and in 4 fractions (total dose 4 Gy) in FS. Tumor inhibition rate and the spleen and thymus index were calculated after the treatments.

RESULTSMI significantly enhanced the efficacy of radiotherapy with a tumor inhibition rate reaching 70% in FS+MI group (P<0.01). FS resulted in a significantly higher tumor inhibition rate than NFS (P<0.05), but the rates were comparable between FS+MI and NFS+MI groups. The spleen index and thymus indices were significantly higher in FS+MI and NFS+MI groups than in FS and NFS groups (P<0.05).

CONCLUSIONMI can enhance the efficacy of radiotherapy with different therapeutic schedules in mice bear Lewis lung cancer, and MI plus fractionated radiation produces the optimal effect.

Animals ; Biological Products ; therapeutic use ; Carcinoma, Lewis Lung ; drug therapy ; radiotherapy ; Combined Modality Therapy ; Dose Fractionation ; Dose-Response Relationship, Radiation ; Male ; Mice ; Mice, Inbred C57BL ; Neoplasm Transplantation ; Radiation-Sensitizing Agents ; therapeutic use ; Streptococcus