Amifostine does not protect thyroid cancer cells in DNA damaging in vitro models

Association Between the XRCC1, GSTM1, and GSTT1 Polymorphisms in Model of Thyroid Cancer: A Meta-Analysis

Thyroid cancer is the most common malignant tumor of the endocrine system, and its incidence is increasing worldwide each year. This study aimed to explore the association between XRCC1, GSTM1, and GSTT1 polymorphisms in the model of thyroid cancer. The experiment was conducted by searching PubMed, Embase, and Web of Science, with the last search performed in March 2022. A total of 12 studies were included in this meta-analysis, with sample sizes ranging from 211 to 1124. The proportion of XRCC1 polymorphisms (rs25489, GG) in thyroid cancer was slightly lower than that of the normal control group, but the difference was not statistically significant (Mean difference=1.13, 95% CI: 0.99-1.28, p=0.08). The proportion of XRCC1 polymorphisms (rs25489, GA) in thyroid cancer was significantly lower than that of the normal control group (Mean difference=1.32, 95% CI: 1.16-1.52, p<0.00001). The proportion of XRCC1 polymorphisms (rs25489, AA) in thyroid cancer was slightly lower than that of the normal control group, but again, the difference was not statistically significant (Mean difference=0.78, 95% CI: 0.61-1.01, p=0.06). Similarly, the proportion of XRCC1 polymorphisms (rs25487, GG) and (rs25487, GA) in thyroid cancer was lower than that of the normal control group, but the differences were not statistically significant (p=0.22 and p=0.49, respectively). In conclusion, this study found that the proportion of XRCC1 polymorphisms (rs25489, AA) in thyroid cancer was lower than that of the normal control group.

Nuclear Ceramide Is Associated with Ataxia Telangiectasia Mutated Activation in the Neocarzinostatin-Induced Apoptosis of Lymphoblastoid Cells

Ceramide is a bioactive sphingolipid that mediates ionizing radiation- and chemotherapy-induced apoptosis. Neocarzinostatin (NCS) is a genotoxic anti-cancer drug that induces apoptosis in response to DNA double-strand breaks (DSBs) through ataxia telangiectasia mutated (ATM) activation. However, the involvement of ceramide in NCS-evoked nuclear events such as DSB-activated ATM has not been clarified. Here, we found that nuclear ceramide increased by NCS-mediated apoptosis through the enhanced assembly of ATM and the meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 (MRN) complex proteins in human lymphoblastoid L-39 cells. NCS induced an increase of ceramide production through activation of neutral sphingomyelinase (nSMase) and suppression of sphingomyelin synthase (SMS) upstream of DSB-mediated ATM activation. In ATM-deficient lymphoblastoid AT-59 cells compared with L-39 cells, NCS treatment showed a decrease of apoptosis even though ceramide increase and DSBs were observed. Expression of wild-type ATM, but not the kinase-dead mutant ATM, in AT-59 cells increased NCS-induced apoptosis despite similar ceramide accumulation. Interestingly, NCS increased ceramide content in the nucleus through nSMase activation and SMS suppression and promoted colocalization of ceramide with phosphorylated ATM and foci of MRN complex. Inhibition of ceramide generation by the overexpression of SMS suppressed NCS-induced apoptosis through the inhibition of ATM activation and assembly of the MRN complex. In addition, inhibition of ceramide increased by the nSMase inhibitor GW4869 prevented NCS-mediated activation of the ATM. Therefore, our findings suggest the involvement of the nuclear ceramide with ATM activation in NCS-mediated apoptosis. SIGNIFICANCE STATEMENT: This study demonstrates that regulation of ceramide with neutral sphingomyelinase and sphingomyelin synthase in the nucleus in double-strand break-mimetic agent neocarzinostatin (NCS)-induced apoptosis. This study also showed that ceramide increase in the nucleus plays a role in NCS-induced apoptosis through activation of the ataxia telangiectasia mutated/meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 complex in human lymphoblastoid cells.

The Radioprotective Effects of Melatonin and Nanoselenium on DNA Double-Strand Breaks in Peripheral Lymphocytes Caused by I-131

Background:

One of the treatment modalities for thyroid cancer and hyperthyroidism is radioiodine-131 (I-131) therapy. The use of this therapeutic modality is not completely safe and can lead to oxidative stress, eventually DNA damages. However, these radiation-induced damages can be reduced by antioxidants. This study aimed to investigate the potential radioprotective effects of melatonin and selenium nanoparticles (SeNPs) on DNA double-stranded breaks (DSBs) caused by I-131.

Materials and Methods:

After obtaining informed consent, 6 ml blood was taken from each volunteer. The samples were divided into two general groups of control (without I-131) and with I-131. Each group was also divided into three subgroups, including without antioxidant, melatonin, and SeNPs. The samples of control group were incubated for 2 h after adding the antioxidants. The samples of I-131 group were first incubated for 1 h with the antioxidants and then the samples re-incubated for another 1 h after adding the I-131. Then, the samples were prepared for γH2AX assay.

Results:

The findings showed that after 1 h of incubation with 20 μCi I-131/2 mL, the DSB levels increased by 102.9% in comparison with the control group. In the I-131 group, there were significant reductions of the DSB levels after incubation with melatonin (P < 0.001) and SeNPs (P < 0.001) in comparison with the without antioxidant subgroup. Furthermore, the DSB levels at the melatonin + I-131 and the SeNPs + I-131 subgroups decreased to 38% and 30%, respectively, compared to the I-131 subgroup.

Conclusion:

According to the obtained findings, it can be concluded that the use of melatonin and SeNPs (as radioprotector agents) can reduce the DSB levels induced by I-131 in peripheral lymphocytes.

Antioxidant Nanomedicine Significantly Enhances the Survival Benefit of Radiation Cancer Therapy by Mitigating Oxidative Stress-Induced Side Effects

Oxidative stress-induced off-target effects limit the therapeutic window of radiation therapy. Although many antioxidants have been evaluated as radioprotective agents, none of them are in widespread clinical use, owing to the side effects of the antioxidants themselves and the lack of apparent benefit. Aiming for a truly effective radioprotective agent in radiation cancer therapy, the performance of a self-assembling antioxidant nanoparticle (herein denoted as redox nanoparticle; RNP) is evaluated in the local irradiation of a subcutaneous tumor-bearing mouse model. Since RNP is covered with a biocompatible shell layer and possesses a core-shell type structure of several tens of nanometers in size, its lifetime in the systemic circulation is prolonged. Moreover, since 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), one of the most potent antioxidants, is covalently encapsulated in the core of RNP, it exerts intense antioxidant activity and induces fewer adverse effects by avoiding leakage of the TEMPO molecules. Preadministration of RNP to the mouse model effectively mitigates side effects in normal tissues and significantly extends the survival benefit of radiation cancer therapy. Moreover, RNP pretreatment noticeably increases the apoptosis/necrosis ratio of radiation-induced cell death, a highly desirable property to reduce the chronic side effects of ionizing irradiation.

Keratinocyte Growth Factor-1 Protects Radioiodine-Induced Salivary Gland Dysfunction in Mice

Background: Most patients with thyroid cancer suffer from salivary gland (SG) dysfunctions after radioiodine (RI) therapy. We investigated the effects of keratinocyte growth factor (KGF)-1 on RI-induced SG dysfunction in an animal model. Methods: Six C57BL/6 mice were assigned to each of the following groups: treatment naïve control group, RI group, and RI+KGF-1 group. Body and SG weights, salivary flow rates, salivary lag times and changes in 99mTc pertechnetate uptake and excretion were measured, and histologic changes were noted. Amylase activities and epidermal growth factor (EGF) concentrations in saliva were also measured. In addition, TUNEL assays were performed and apoptosis-related protein expressions were assessed. Results: RI-induced reductions in salivary flow rates and increases in salivary lag times observed in the RI group were not observed in RI+KGF-1 group. Mice in RI group had higher HIF1a levels than controls, but HIF1a levels in RI+KGF-1 group were similar to those in control group. Furthermore, mice in RI+KGF-1 group had more mucin stained acini and decreased periductal fibrosis than mice in RI group, and tissue remodeling of many salivary epithelial cells (AQP5) and endothelial cells (CD31) were observed in RI+KGF-1 group. Amylase activity and expression in saliva were greater in RI+KGF-1 group than in RI group, and fewer apoptotic cells were observed in RI+KGF-1 group. Furthermore, BCLxl (anti-apoptotic) expression was higher, and Bax (pro-apoptotic) expression was lower in RI+KGF-1 group than in RI group. Conclusions: Local delivery of KGF-1 might prevent RI-induced SG damage by reducing apoptosis.

The Radioprotective Effects of Curcumin and Trehalose Against Genetic Damage Caused By I-131

Background:

Thyroid cancer has been growing rapidly during the last decades. Radioiodine-131 (I-131) as an appropriate therapy modality is currently using in the treatment of cancer and hyperthyroidism diseases. This radiotracer is considered as a cause of oxidative DNA damage in nontarget cells and tissues. The aim of this study was to investigate the effects of curcumin and trehalose on the level of DNA double-strand breaks (DSBs) caused by I-131 in human lymphocytes.

Materials and Methods:

First, 6-mL blood samples were taken from each of the five volunteers. After 1 h of preincubation with the antioxidants, a total of 20 μCi I-131/2 mL (blood + NaCl) was added to each sample, and then, the samples were reincubated for 1 h. Lymphocytes were separated and the mean DSB levels were measured for each sample through γ-H2AX assay to evaluate the effects of antioxidants.

Results:

After 1-h incubation with I-131, the DSBs increased by 102.9% compared to the control group (0.343 vs. 0.169 DSB/cell; P = 0.00). Furthermore, compared to the control + I-131 group, curcumin and trehalose reduced the DSBs by 42% and 38%, respectively. There was a significant decrement (P = 0.00) in the levels of DSBs of the curcumin + I-131 and trehalose + I-131 subgroups compared to the control + I-131 subgroup. Furthermore, there was no significant relationship between the radioprotective effect of curcumin and trehalose (P = 0.95).

Conclusion:

The use of curcumin and trehalose as antioxidant can reduce the numbers of DSBs caused by I-131. Meanwhile, the radioprotective effect of curcumin was more than trehalose.