Effects of the DNA repair inhibitors, cytosine arabinoside and 3-aminobenzamide, on the frequency of radiation-induced micronuclei, nuclear buds, and nucleoplasmic bridges

Interferon-γ liposome: a new system to improve drug delivery in the treatment of lung cancer

Lung cancer is one of the main causes of death worldwide. Published data show the use of interferons (IFNs) in treating lung tumours. IFNs also have potential for their antiproliferative, antiangiogenic, immunoregulatory and proapoptotic effects. IFN-γ functions as an anticancer agent against various forms of cancer. This study aimed to investigate the effect of IFN-γ liposome (nano) on peripheral lymphocytes from 20 individuals in each group: lung cancer patients compared to healthy individuals. The effectiveness of IFN-γ liposome against oxidative stress was also evaluated in this study. A concentration of 100 U·mL-1 of IFN-γ liposome was used to treat the lymphocytes in the Comet and micronucleus assays based on the preliminary test for the optimal dose. The lymphocytes from lung cancer patients presented with higher DNA damage levels than those of healthy individuals. In healthy individuals, IFN-γ liposome did not cause any DNA damage in the lymphocytes. Also, it caused a significant reduction in DNA damage in the lymphocytes from lung cancer patients in both the Comet and micronucleus assays. The 100 U·mL-1 of IFN-γ liposome significantly reduced the oxidative stress caused by H2O2 and appeared to be effective in both groups using the Comet and micronucleus assays. Results from both Comet and micronucleus assays were consistent. The data obtained indicated that IFN-γ in both forms (IFN-γ bulk and IFN-γ nanoliposome) may potentially be effective for the treatment of lung cancer and showed the ability of IFN-γ liposome to reduce DNA damage more than the bulk form.

Dose-effect relationships of 12C6+ ions-induced dicentric plus ring chromosomes, micronucleus and nucleoplasmic bridges in human lymphocytes in vitro

PURPOSE

The objective of this research was to explore the dose-effect relationships of dicentric plus ring (dic + r), micronucleus (MN) and nucleoplasmic bridges (NPB) induced by carbon ions in human lymphocytes.

MATERIALS AND METHODS

Venous blood samples were collected from three healthy donors. 12C6+ ions beam was used to irradiate the blood samples at the energy of 330 MeV and linear energy transfer (LET) of 50 keV/μm with a dose rate of 1 Gy/min in the spread-out Bragg peak. The irradiated doses were 0 (sham irradiation), 1, 2, 3, 4, 5 and 6 Gy. Dic + r chromosomes aberrations were scored in metaphases. The cytokinesis-block micronucleus cytome (CBMN) was conducted to analyze MN and NPB. The maximum low-dose relative biological effectiveness (RBEM) values of the induction of dic + r, MN and NPB in human lymphocytes for 12C6+ ions irradiation was calculated relative to 60Co γ-rays.

RESULTS

The frequencies of dic + r, MN and NPB showed significantly increases in a dose-depended manner after exposure to 12C6+ ions. The distributions of dic + r and MN exhibited overdispersion, while the distribution of NPB agreed with Poisson distribution at all doses. Linear-quadratic equations were established based on the frequencies of dic + r and MN. The dose-response curves of NPB frequencies followed a linear model. The derived RBEM values for dic + r, MN and NPB in human lymphocytes irradiated with 12C6+ ions were 8.07 ± 2.73, 2.69 ± 0.20 and 4.00 ± 2.69 in comparison with 60Co γ-rays.

CONCLUSION

The dose-response curves of carbon ions-induced dic + r, MN and NPB were constructed. These results could be helpful to improve radiation risk assessment and dose estimation after exposed to carbon ions irradiation.

Effects of radiation quality and dose rate on radiation-induced nucleoplasmic bridges in human peripheral blood lymphocytes

Previous studies showed that the yield of cobalt-60 γ-rays-induced nucleoplasmic bridges (NPB) in human peripheral blood lymphocytes is dose dependent. However, the influence of the radiation quality and dose rates on NPB frequencies has not been investigated. The present study aimed to investigate NPB frequencies in human peripheral blood lymphocytes induced by carbon ions and explore the dose rate effect on cobalt-60 γ-rays-induced NPB. To establish dose-response curves, human peripheral blood samples were irradiated with 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 and 8.0 Gy of carbon ions at a dose rate of 3.0 Gy/min in vitro. To explore the dose rate effect, human peripheral blood samples were irradiated with 2.0 and 5.0 Gy of cobalt-60 γ-rays at dose rates of 0.2, 0.5, 1.0, 3.0, 5.0 and 10.0 Gy/min in vitro. NPB and micronuclei (MN) in binucleated cells were analyzed with the cytokinesis-block micronucleus cytome assay. Results showed that the dose-response curve of carbon ion-induced NPB frequencies follow a linear-quadratic model (R² = 0.934). The relative biological effectiveness (RBE) values of carbon ions to cobalt-60 γ-rays decreased with increased NPB frequencies (ranging from 2.47 to 5.86). Compared with group 1.0 Gy/min, the NPB frequencies in groups 10.0 Gy/min (2.0 Gy), 5.0 and 10.0 Gy/min (5.0 Gy) were decreased significantly (P < 0.05). Carbon ion-induced NPB in human peripheral blood lymphocytes have a good dose-response relationship. Cobalt-60 γ-rays-induced NPB frequencies are affected by the specific dose rate.