Biological effects of (125)i seeds radiation on A549 lung cancer cells: G2/M arrest and enhanced cell death

Advances in studies on tracheal stent design addressing the related complications

Tracheal stents can be used to quickly reconstruct the airway and relieve symptoms of dyspnea in patients with tracheal stenosis. However, existing tracheal stents lead to complications such as granulation tissue formation, difficulty in removal, persistent growth of malignant tumors, stent migration, and mucus plugging. In this article, we reviewed the main methods used to reduce complications associated with tracheal stent design. Drug-eluting stents can inhibit granulation tissue formation and prevent infection and local chemotherapy. The biodegradable stent can support the trachea for some time, maintain tracheal patency, and degrade gradually, which avoids removing or replacing the stent. Radioactive stents loaded with I125 have good potential for inhibiting the persistent growth of malignant tumors. Three-dimensional printing technology enables the manufacturing of patient-specific stents, which increases the degree of matching between the complex tracheal anatomy and the stent, thus providing a new solution for stent migration caused by structural mismatch. Minimizing the barrier of the stent to mucociliary clearance, providing an anti-fouling coating, and culturing respiratory epithelial cells on the surface of the stent are the main methods used to reduce mucus plugging. We also proposed future research directions for tracheal stents to guide the design and manufacture of ideal tracheal stents.

Treatment of malignant airway obstruction with Y-shape sigma stent loaded with I125 seeds installed via rigid bronchoscopy

PURPOSE

To summarize and analyze the safety and efficacy of a Y-shape Sigma stent loaded with I125 in patients with inoperable malignant main airway obstruction.

METHODS

This study was approved by the Institutional Ethics Committee, and a written informed consent was obtained from each participant. A Y-shape Sigma stent loaded with I125 was placed under vision from rigid bronchoscopy. The primary endpoint was alleviation of symptoms and improvement of Karnofsky Performance Status (KPS) score, and the secondary endpoint was complications and technical success.

RESULTS

From November 2018 through June 2023, total 33 patients with malignant airway obstruction were palliatively treated by installing Y-shape Sigma stents loaded with I125. The airway lumen was immediately restored and the average airway opening significantly increased to 70 ± 9.4% after the procedure from baseline 30.2 ± 10.5% (p < 0.05). Average KPS score was improved from baseline 30.0 ± 10.0 to 70.0 ± 10.0 (p < 0.05) as well as PaO2 from baseline 50.1 ± 15.4 mmHg to 89.3 ± 8.6 mmHg (p < 0.05). The technical success rate of placing the stent in this study was 73%, and adverse events or complications including bleeding, I125 loss, and airway infection occurred during or after the procedure.

CONCLUSION

Placement of Y-shape Sigma stents under vision from rigid bronchoscopy in the patients with malignant airway obstruction is feasible and it immediately alleviates dyspnea and significantly improves quality of life.

Effects of iodine-125 seed brachytherapy on patients with heterochronous pulmonary metastasis from hepatocellular carcinoma: A propensity score matching study

Purpose

To investigate the effects of iodine-125 seed brachytherapy (ISB) on the overall survival (OS) of patients with heterochronous pulmonary metastasis (HPM) secondary to hepatocellular carcinoma (HCC).

Materials and Methods

The clinical and imaging data of 123 patients with HPM secondary to HCC treated at a single center from July 2012 to July 2020 were analyzed retrospectively. The patients were divided into ISB and non-ISB groups based on ISB treatment. Propensity score matching yielded 46 pairs of patients. A total of 191 lesions were treated, and the data were evaluated for 6 months after ISB. The OS rates of the two groups were compared using the Kaplan-Meier method. Independent prognostic factors were determined using a Cox proportional hazards regression model.

Results

The percentages of lung lesions in complete remission, partial remission, disease stable, and disease progression stages were 49.2%, 32.8%, 9.6%, and 8.4%, respectively. The disease control rate was 91.6%. The median follow-up time from the initial diagnosis was 47 months and 33 months for the ISB and non-ISB groups, respectively. Patients in the ISB group had a longer OS than those in the non-ISB group (1-year: 95.7% vs. 80.3%; 3-year: 62.9% vs. 45.7%; 5-year: 37% vs. 20.9%; P < 0.05). Multivariate analysis demonstrated that ISB treatment, tumor differentiation, vascular invasion, and Child - Pugh score were independent prognostic factors for survival.

Conclusion

ISB improves local control and OS rates of HPM secondary to HCC; thus, it is an effective and feasible option for patients with HPM secondary to HCC.

Stent loaded with radioactive Iodine-125 seeds for adenoid cystic carcinoma of central airway: A case report of innovative brachytherapy

Adenoid cystic carcinoma (ACC) of central airway is very rare. More than half of ACCs are unresectable for tumor extension. There’s rare report on local ACCs only in central airway. We present a case of ACC in central airway who underwent an innovative brachytherapy. A 44-year-old woman was diagnosed with primary ACC in central airway without regional lymphadenopathy or metastatic disease. Stenosis was observed in lower trachea and both left and right main bronchi (stenosis in lumen ≥50%) with bronchoscopy. The tumor was unresectable due to local extension. A Y-shaped and stainless-steel stent loaded with radioactive 125I seeds was placed in the central airway using bronchoscope. The number and distribution of 125I seeds were planed using treatment planning system. The stent was removed three months later. The patient tolerated the procedure well. She was alive without relapse three years after removing the stent with 125I seeds. This case demonstrates the successful use of stent with radioactive 125I seeds for unresectable ACCs in central airway. In the procedure, the stent was placed with bronchoscope and under the vision from bronchoscope. This innovative brachytherapy is well-tolerated, safe, precise and individualized designed. The patient with unresectable ACCs could get a long-term relapse-free survival. Clinical trials could be taken to validate its effectiveness and tolerability in patients with ACCs of central airway.

Iodine-125 Seeds Inhibit Carcinogenesis of Hepatocellular Carcinoma Cells by Suppressing Epithelial-Mesenchymal Transition via TGF-β1/Smad Signaling

To investigate the radioactive iodine-125 (I-125) seed on migrating and invading of hepatocellular carcinoma (HCC) cells and its mechanism, the irradiation of PLC and Huh7 cells was carried out with I-125 seeds in vitro. Cell counting kit 8 assay was employed to measure cell viability. Cell migration was evaluated by using wound-healing assay. Cell invasion was detected by Transwell assay; RT-PCR and Western blot were used for the detection of the mRNA and proteins of TGF-β1 signaling pathway-related genes. The viability of PLC and Huh7 cells declined in a dose-dependent manner with increasing irradiation from 0 Gy, 2 Gy, 4 Gy, and 6 Gy, to 8 Gy, respectively. The IC50 of PLC and Huh7 cells were 6.20 Gy and 5.39 Gy, respectively, after 24 h of irradiation. Migration and invasion abilities of I-125 group cells were greatly weakened (P < 0.05) comparing with the control group. According to the outcomes of RT-PCR and WB, I-125 seed irradiation significantly inhibited the mRNA and protein expression of N-cadherin, vimentin, TGF-β1, p-Smad2/3, and Snail. But the mRNA and protein expressions of E-cadherin were enhanced. Rescue experiment demonstrates that TGF-β1 activator could reverse the inhibitory effects of I-125 on invasion and migration of cells. The results of in vivo experiments further verified that the I-125 seeds can inhibit the proliferation and TGF-β1 of xenographed PLC cells. In conclusion, I-125 seeds restrain the invasion and migration of HCC cells by suppressing epithelial to mesenchymal transition, which may associate with the inhibition of the TGF-β1 signaling.

Administration of Iodine-125 Seeds Promotes Apoptosis in Cholangiocarcinoma through the PI3K/Akt Pathway

Purpose. We aimed to examine the effects of 125I seeds on the gene expression of Bcl-2, Bax, and PI3K/Akt pathway components in cholangiocarcinoma cells. Methods. In vitro, human cholangiocarcinoma RBE cells were treated with 125I seeds (0.39 mCi or 0.85 mCi) for 72 h, 120 h, and 168 h. Cell proliferation and apoptosis were assessed. The expression of Bcl-2 and Bax was detected by RT-PCR, and Western blotting was carried out to explore changes in Akt activity. Result. 125I seeds inhibited the proliferation of RBE cells. The apoptosis rate of the RBE cells in the low-activity group was significantly higher than that in the high-activity group at 120 h and 168 h, while no difference was found between the two groups at 72 h. After 120 h of culture, the gene expression of Bcl-2 and Bax decreased in both groups, the ratio of $\text{Bcl}-2/\text{Bax}$ in the low-activity group decreased, and the PI3K/Akt signaling pathway was inhibited in both groups. Conclusion. 125I seeds affect the proliferation and apoptosis of cholangiocarcinoma cells in a dose-dependent manner. The therapeutic effect of low-activity 125I seeds on cancer cells may be better. 125I seed brachytherapy may promote the apoptosis of cholangiocarcinoma cells by inhibiting the PI3K/Akt signaling pathway and regulating the $\text{Bcl}-2/\text{Bax}$ ratio.

Effects of I-125 seeds combined with anlotinib on tumor growth and bone metabolism in A549 tumor-bearing mice

PURPOSE

This study aimed to investigate the therapeutic potential of tumor suppression and mechanism for different implantation modes of iodine-125 (I-125) seeds irradiation in a mice xenograft model, and its skeletal complications.

MATERIALS AND METHODS

A total of 24 mice carrying A549 lung tumor-derived xenografts were randomly assigned to four groups, including non-radioactive (sham) seeds implantation, I-125 seeds fractional implantation, I-125 seeds single implantation and I-125 seeds single implantation combined with anlotinib. Ki67 immunohistochemistry, TUNEL immunofluorescence and CD31 morphometric analysis were used to determine the proliferation index, rate of apoptotic cells and microvessel density, respectively. Additionally, the side effects on the skeletal system in mice treated with I-125 seeds implantation were evaluated by histomorphometric staining with tartrate-resistant acid phosphate (TRAP) and alkaline phosphatase (ALP) expression in femur, tartrate-resistant acid phosphatase 5b (TRACP-5b) and procollagen type I N-terminal propeptide (PINP) levels in serum were evaluated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The I-125 seeds single and fractionated implantation had similar therapeutic effects and complications when the total number of I-125 seeds was the same. A single implantation of I-125 seeds with or without anlotinib could analogously inhibit the tumor growth in xenografts mice, while the single implantation combined with anlotinib had more effective in tumor inhibition. The results of Ki67, TUNEL and CD31 staining confirmed an evident reduction in tumor cell proliferation and angiogenesis, as well as an increase in apoptosis. A relatively integrated bone metabolism was indicated after I-125 seeds single implantation with or without anlotinib, and the results were similar in I-125 seeds fractional implantation, including a reduction in the number of TRAP-positive cells and an increase in ALP expression level. Additionally, the serum TRACP-5b activity was decreased and the serum PINP concentration was increased following I-125 seeds implantation.

CONCLUSIONS

Single and fractionated implantation pattern of I-125 radioactive seeds had similar therapeutic efficacy against tumor growth, while brachytherapy with I-125 seeds implantation may be an effective and safe treatment strategy for its potential protection against cancer treatment-induced bone loss.

RECQ1 Promotes Stress Resistance and DNA Replication Progression Through PARP1 Signaling Pathway in Glioblastoma

Glioblastoma (GBM) is the most common aggressive primary malignant brain tumor, and patients with GBM have a median survival of 20 months. Clinical therapy resistance is a challenging barrier to overcome. Tumor genome stability maintenance during DNA replication, especially the ability to respond to replication stress, is highly correlated with drug resistance. Recently, we identified a protective role for RECQ1 under replication stress conditions. RECQ1 acts at replication forks, binds PCNA, inhibits single-strand DNA formation and nascent strand degradation in GBM cells. It is associated with the function of the PARP1 protein, promoting PARP1 recruitment to replication sites. RECQ1 is essential for DNA replication fork protection and tumor cell proliferation under replication stress conditions, and as a target of RECQ1, PARP1 effectively protects and restarts stalled replication forks, providing new insights into genomic stability maintenance and replication stress resistance. These findings indicate that tumor genome stability targeting RECQ1-PARP1 signaling may be a promising therapeutic intervention to overcome therapy resistance in GBM.

The Clinical Value of Computed Tomography (CT)-Guided 125I Brachytherapy for Locally Advanced Non-Small Cell Lung Cancer After Progression of Concurrent Radiochemotherapy

Purpose

To further evaluate the efficacy and safety of computed tomography (CT)-guided iodine 125 (¹²⁵I) brachytherapy to treat locally advanced non-small cell lung cancer (NSCLC) after progression of concurrent radiochemotherapy (CCRT).

Methods

This study obtained written consent from all patients and was approved by our institution. From January 2006 to June 2018, 210 NSCLC patients (progression of first-line CCRT) were retrospectively recruited and then divided into two groups. A total of 116 patients were given CT-guided ¹²⁵I brachytherapy and second-line chemotherapy (group A), and 94 were treated with second-line chemotherapy alone (group B).

Results

In group A, local response rate (LRR) within 3 years was significantly better (P<0.05). Mean survival time [progression-free survival time (PFST) and overall survival (OS)] was 15.1±1.4 months and 21.2±1.6 months in group A compared with 10.0±1.4 months and 16.2±1.7 months in group B (PFST: P<0.01, HR=1.472, 95% CI 1.097–1.975; OS: P = 0.036, HR=1.342, 95% CI 1.005–1.791). Tumor size and No. of first cycle chemotherapy were independent factors that affected survival, ≤3cm largest tumor diameter and more than 4 first cycles of chemotherapy showed longer PFST and OS (P<0.05). Tumor-related clinical symptoms were relieved in group A (P<0.01). No serious complications occurred in the two groups.

Conclusion

¹²⁵I brachytherapy is effective and safe in locally advanced NSCLC after progression of CCRT.

Combined effects of low-dose gambogic acid and NaI131 in drug-resistant non-small cell lung cancer cells

Radioactive seed brachytherapy is a method for treating drug-resistant, late-stage non-small cell lung cancer (NSCLC). To elucidate the mechanism of low-dose gambogic acid (GA) and NaI¹³¹ in drug-resistant NSCLC cells, the human NSCLC A549 cell line and the drug-resistant A549/cisplatin (DDP) and A549/Taxol cell lines were treated with NaI¹³¹, low-dose GA or a combination of both in the present study; the control group of each cell line was treated with phosphate-buffered saline (PBS). Following treatment, cell proliferation, apoptosis and cell cycle analysis was performed. Apoptosis-related proteins, namely CDK1, cyclin B, mutant p53 (mtp53), heat shock protein 90 (HSP90), Bax and Bcl-2, and P-glycoprotein 1 (P-gp), which is known to confer resistance to chemotherapy, were detected using western blotting and immunofluorescence analysis. mRNA levels of p53 and HSP90 were measured using reverse transcription-quantitative PCR. Compared with the PBS control group, the A549, A549/DDP and A549/Taxol cells treated with NaI¹³¹, GA or a combination of the drugs exhibited G₂/M arrest and increased percentages of total apoptotic cells, as well as significantly decreased protein levels of CDK1, cyclin B, mtp53, HSP90, Bcl-2 and P-gp, increased protein levels of Bax and decreased mRNA levels of p53 and HSP90. The changes in the combination group were the most evident and were significantly different from the other groups (P<0.001). In conclusion, low-dose GA may be a potential radionuclide sensitizer.

Coralyne Radiosensitizes A549 Cells by Upregulation of CDKN1A Expression to Attenuate Radiation Induced G2/M Block of the Cell Cycle

Coralyne is a synthetic analog of berberine related to protoberberine-isoquinoline alkaloids. Isoquinoline derivatives and analogs are renowned as potent radiosensitizers with potential medical application. In the present study, we investigated the effect of coralyne on the cell death, cytoskeletal changes and cell cycle progression of irradiated A549 cells. A clonogenic assay revealed that coralyne pretreatment decreased the viability of A549 cells in a time- and dose-dependent manner. Moreover, exposure to coralyne and ionizing radiation (IR) markedly altered the filamentous actin cytoskeletal architecture and integrin-β binding sites of A549 cells. Treatment with 1–25 µM coralyne in combination with 2 Gy of IR significantly reduced the percentage of cells in G2/M phase compared with 2 Gy IR alone. These results indicate that coralyne is a potent radiosensitizing agent that may find an application in medicine.

Computed tomography-guided implantation of 125I radioactive seeds in patients with malignant airway compression induced by advanced lung cancer: effectiveness and safety in 40 patients

Purpose

To evaluate the safety and efficacy of computed tomography (CT)-guided ¹²⁵I radioactive seed implantation in patients with malignant airway compression induced by advanced lung cancer.

Material and methods

Between June 2015 and June 2018, 40 patients from three medical institutions with malignant airway compression induced by advanced lung cancer were treated with ¹²⁵I seed implantation. The outcomes were measured in technical success and safety, objective response rate, complications, Karnofsky performance status (KPS) score, and survival time.

Results

All 40 patients successfully underwent implantation procedure. No procedure-associated death occurred. The most common complications were irritable cough, temporary hemoptysis, chest pain, fever, and pneumothorax, which occurred in 26 (65.0%), 31 (77.5%), 12 (30.0%), 15 (37.5%), and 11 (27.5%) patients, respectively. The objective response rates were 100%, 100%, 100%, 87.5%, and 83.3% at the 3^rd, 6^th, 12^th, 24^th, and 36^th months post-procedure, respectively. The KPS score significantly improved at post-procedure. Median survival time was 25.1 months. Actuarial survival rates were 100%, 60%, and 15% at the 12^th, 24^th, and 36^th months after the procedure, respectively.

Conclusions

For patients with malignant airway compression induced by advanced lung cancer, implantation with ¹²⁵I seed is a safe and effective alternative treatment option.

125I Seed Brachytherapy Combined with Single-Agent Chemotherapy in the Treatment of Non-Small-Cell Lung Cancer in the Elderly: A Valuable Solution

Purpose

The aim of this study was to compare the effectiveness and safety of CT-guided ¹²⁵I seed brachytherapy combined with single-agent chemotherapy versus combined chemotherapy in the treatment of elderly NSCLC.

Materials and Methods

We retrospectively analyzed 110 patients (64 men and 46 women; mean age=71.25±7.14 years) who were diagnosed with NSCLC without distant metastases between January 2015 and May 2020. A total of 50 patients received ¹²⁵I brachytherapy combined with single-agent chemotherapy (group A), whereas 60 patients received combined chemotherapy (group B). The response to therapy and adverse effect were compared between groups. The local response rate was evaluated by CT. Progression-free survival (PFS) and overall survival (OS) data were obtained through clinical follow-up.

Results

All patients had been treated and were followed-up for 3-60 months. The median OS and PFS were 23.71±1.41 months (95% CI=20.95-26.47) vs 16.12±0.93 months (95% CI=14.31-17.93) (P<0.05) and 15.08±0.85 months (95% CI=13.42-16.74) vs 10.03±0.53 months (95% CI=9.01-11.06) (P<0.05) in group A and group B, respectively. The local response rate and clinical symptoms of patients in group A were significantly relieved when compared with group B. Severe complications were not observed in either group.

Conclusion

CT-guided ¹²⁵I seed brachytherapy combined with single-agent chemotherapy is an effective and safe therapy and shows promising results compared to combined chemotherapy alone for NSCLC in the elderly. A randomized study will be needed to assess the superiority of this combined modality treatment.

Iodine‑125 seed radiation induces ROS‑mediated apoptosis, autophagy and paraptosis in human esophageal squamous cell carcinoma cells

Iodine-125 (¹²⁵I) seed brachytherapy has been proven to be a safe and effective treatment for advanced esophageal cancer; however, the mechanisms underlying its actions are not completely understood. In the present study, the anti-cancer mechanisms of ¹²⁵I seed radiation in human esophageal squamous cell carcinoma (ESCC) cells (Eca-109 and KYSE-150) were determined, with a particular focus on the mode of cell death. The results showed that ¹²⁵I seed radiation significantly inhibited cell proliferation, and induced DNA damage and G2/M cell cycle arrest in both ESCC cell lines. ¹²⁵I seed radiation induced cell death through both apoptosis and paraptosis. Eca-109 cells were primarily killed by inducing caspase-dependent apoptosis, with 6 Gy radiation resulting in the largest response. KYSE-150 cells were primarily killed by inducing paraptosis, which is characterized by extensive cytoplasmic vacuolation. ¹²⁵I seed radiation induced autophagic flux in both ESCC cell lines, and autophagy inhibition by 3-methyladenine enhanced radiosensitivity. Furthermore ¹²⁵I seed radiation induced increased production of reactive oxygen species (ROS) in both ESCC cell lines. Treatment with an ROS scavenger significantly attenuated the effects of ¹²⁵I seed radiation on endoplasmic reticulum stress, autophagy, apoptosis, paraptotic vacuoles and reduced cell viability. In vivo experiments showed that ¹²⁵I seed brachytherapy induced ROS generation, initiated cell apoptosis and potential paraptosis, and inhibited cell proliferation and tumor growth. In summary, the results demonstrate that in ESCC cells, ¹²⁵I seed radiation induces cell death through both apoptosis and paraptosis; and at the same time initiates protective autophagy. Additionally, ¹²⁵I seed radiation-induced apoptosis, paraptosis and autophagy was considerably mediated by ROS.

The Stapled Peptide PM2 Stabilizes p53 Levels and Radiosensitizes Wild-Type p53 Cancer Cells

The tumor suppressor p53 is a key mediator of cellular stress and DNA damage response cascades and is activated after exposure to ionizing radiation. Amplifying wild-type p53 expression by targeting negative regulators such as MDM2 in combination with external beam radiotherapy (EBRT) may result in increased therapeutic effects. The novel stapled peptide PM2 prevents MDM2 from suppressing wild-type p53, and is thus a promising agent for therapeutic combination with EBRT. Effects of PM2 and potential PM2-induced radiosensitivity were assessed in a panel of cancer cell lines using 2D cell viability assays. Western Blot and flow cytometric analyses were used to investigate the mechanisms behind the observed effects in samples treated with PM2 and EBRT. Finally, PM2-treatment combined with EBRT was evaluated in an in vitro 3D spheroid model. PM2-therapy decreased cell viability in wild-type p53, HPV-negative cell lines. Western Blotting and flow cytometry confirmed upregulation of p53, as well as initiation of p53-mediated apoptosis measured by increased cleaved caspase-3 and Noxa activity. Furthermore, 3D in vitro tumor spheroid experiments confirmed the superior effects of the combination, as the only treatment regime resulting in growth inhibition and complete spheroid disintegration. We conclude that PM2 induces antitumorigenic effects in wt p53 HPV-negative cancer cells and potentiates the effects of EBRT, ultimately resulting in tumor eradication in a 3D spheroid model. This strategy shows great potential as a new wt p53 specific tumor-targeting compound, and the combination of PM2 and EBRT could be a promising strategy to increase therapeutic effects and decrease adverse effects from radiotherapy.

Glutamine synthetase facilitates cancer cells to recover from irradiation-induced G2/M arrest

Resistance to radiation of cancer cells can be either intrinsic or acquired, leading to treatment failure. In response to DNA damage caused by IR, cancer cells are arrested in cell cycle showing limited proliferation and increased apoptosis. However, radiation-resistant cells are able to overcome the cell cycle block and proceed to proliferation, for which the detailed mechanism remains to be elucidated. In the present study, we showed that radioresistant cells exhibited a recoverable G2/M phase during prolonged cell cycle and manifested lower apoptosis rate and more colony formation. RNA-seq analysis revealed that glutamine synthetase (GS, GLUL) gene was highly expressed in radioresistant cancer cells in comparison with the parental cells, which was in accordance with the G2/M arrest after ionizing radiation. Knocking out of GS in radioresistant cells resulted in a delayed G2/M recovery and lowered proliferation rate after ionizing radiation treatment, which was accompanied with increased inhibitory phosphorylation of CDK1 at Y15 and downregulated Cdc25B, a dual specific phosphatase of CDK1. Moreover, there was an enhanced complex formation of CDK1 and Cyclin B1 when the cells were rescued by re-introducing GS. In vivo, knocking down of GS significantly sensitized CNE2-R xenografts to RT in mice. In this study, we demonstrate a novel role of glutamine synthetase independent of metabolic function in promoting recovery from G2/M arrest caused by ionizing radiation, thus, causing cancer cell resistance to radiotherapy.

Safety and efficacy of 125I brachytherapy for bilateral lung recurrences from hepatocellular carcinoma after resection or ablation

PURPOSE

To evaluate the safety and efficacy of 125I brachytherapy to treat bilateral lung recurrences from hepatocellular carcinoma (HCC) after resection or ablation.

MATERIALS AND METHODS

We retrospectively recruited 95 patients with bilateral lung recurrences from hepatocellular carcinoma (HCC) after resection or ablation who had received 3-6-month sorafenib with or without stereotactic body radiotherapy (SBRT), from October 2011 to January 2015; patients were then randomly divided into two groups, 44 patients received computed tomography (CT)-guided 125I brachytherapy (group A), and 51 patients were treated with supportive and symptomatic treatments (group B).

RESULTS

The median survival time was 19 months (range of 3-36 months). The local response rate (LRR) at 3, 6, 12, 18, 24, 30 and 36 months in group A was 81.8%, 65.9%, 59.1%, 45.0%, 38.6%, 22.7%, 11.4%, respectively, and 64.7%, 47.1%, 33.3%, 25.4%, 15.7%, 11.7%, 7.8%, respectively, in group B (P < 0.05). The mean progression-free survival time (PFST) and overall survival (OS) of group A were significantly longer than those of group B. Alpha fetoprotein (AFP) and tumor size were independent factors that affected the PFST and OS, normal AFP levels and less than 1-cm tumor diameter had better PFST and OS (P < 0.05). No massive bleeding or serious complications occurred.

CONCLUSION

CT-guided 125I brachytherapy is safe and effective for the treatment of bilateral lung recurrences from HCC after resection or ablation.

Iodine-125 seed implantation combined with arterial chemoembolization therapy for pain palliation in metastatic bone cancer: a retrospective study

Bone metastases are the most common sites for malignant tumors. Patients who failed to respond to initial first-line treatment with bisphosphonates usually suffer from extreme pain. The aim of this study was to observe the efficacy of arterial chemoembolization combined with Iodine-125 seed implantation in the treatment of bone metastatic cancer pain. All 14 patients with metastatic bone tumor wo failed first-line treatment underwent arterial chemoembolization the day before the implantation of the particles. A computer stereoscopic TPS was used to design the treatment plans, the number and dose of particles required for implantation. Pain relief was evaluated using several parameters such as Visual Analog Scale (VAS) and Verbal Rating Scales (VRS). Pain intensity was measured pre-operation and 1-week, 1-month, 3-month after the treatment. Meanwhile, we also assessed tumor size using computer tomography (CT). Pain palliation was observed in 35.7% (5/14), 57.1% (8/14), and 78.6% (11/14) of all patients at 1-week, 1-month and 3-month post treatment. Likewise, our analysis showed that the combination therapy resulted in a significant decrease of VAS score (6.71 ± 0.49 before treatment vs 3.36 ± 0.40 at 3 month post treatment) and overall responding rate of 92.0% using VRS pain assessment. Consistently, tumor size was reduced from 42.16 ± 10.32 before treatment to 29.11 ± 8.73 at 3 months post treatment. No serious complications were detected. Our study demonstrate that the combination of arterial chemoembolization and ¹²⁵I particles resulted in evident pain relief and reduction of tumor burden, suggesting that the combination treatment could be a feasible and promising therapy for bone tumor management.

Iodine-125 interstitial brachytherapy reduces tumor growth via Warburg effect inhibition in non-small cell lung cancer A549 ×enografts

Iodine-125 interstitial brachytherapy (125I-IBT) is an alternative and effective treatment option for unresectable non-small cell lung cancer (NSCLC), and the Warburg effect is a determinant of tumor growth. The present study aimed to explore the influence of 125I-IBT on tumor growth and the Warburg effect, and the potential mechanisms underlying NSCLC progression. Mice with A549 cell xenografts were evenly divided into a control group without 125I-IBT, and three treatment groups receiving 125I-IBT with 20, 40 and 60 Gy. Tumor volume (TV), maximum standardized uptake value (SUVmax) determined by 18F-fluorodeoxyglucose (18F-FDG) micro-positron emission tomography/computed tomography and mean optical density (MOD) of mammalian target of rapamycin (mTOR), c-Myc, hypoxia inducible factor-1α (HIF-1α) and glucose transporter 1 (GLUT1) staining were compared among groups. Tumor inhibition rate (TIR), 18F-FDG uptake attenuation rate (FUAR) and expression suppression rate (ESR) were also calculated on day 14 and 28. The results demonstrated that the mean TV in the 60 and 40 Gy groups was smaller compared with the control TVs since days 14 and 16, respectively. The mean SUVmax value of the 60 Gy group at day 14, and all treatment group SUVmax values at day 28 were lower compared with the controls. In addition, the MOD of mTOR and GLUT1 was lower in the 60 Gy group, compared with the other groups, and c-Myc and HIF-1α values were lower in the 40 and 60 Gy groups, compared with the control and 20 Gy group (P<0.05). SUVmax positively correlated to TV (day 14, r=0.711; day 28, r=0.586) and the MOD of c-Myc and GLUT1 (r=0.621 and 0.546, respectively; P<0.01). Furthermore, dose dependent increases were observed for TIR, FUAR and ESR. In conclusion, 125I-IBT reduced tumor growth by inhibiting the Warburg effect, which may have resulted from downregulation of mTOR, c-Myc, HIF-1α and GLUT1 expression, particularly c-Myc and GLUT1, in NSCLC A549 ×enografts.

A Novel Tracheobronchial Stent Loaded with 125I Seeds in Patients with Malignant Airway Obstruction Compared to a Conventional Stent: A Prospective Randomized Controlled Study

Background

To evaluate the safety and efficacy of a novel radioactive bare metal stent (RBMS) compared with a conventional bare metal stent (CBMS) in patients with inoperable malignant airway obstruction.

Methods

This prospective study was approved by the Institutional Ethics Committee, and informed consent was obtained from each participant. Patients with malignant airway obstruction who had dyspnea were randomly assigned to receive RBMS or CBMS placement. The primary endpoint was stenosis grade, while the secondary endpoints were technical success, overall survival, and complications. A p value of <0·05 was considered statistically significant.

Results

Between September 2013 and July 2015, 66 patients with inoperable malignant airway obstruction received stent placement fluoroscopically (33 in either group). The median follow-up time was 154 days (range, 15–335 days). The baseline stenosis was immediately relieved in both groups after stent placement, and the stenosis grades in the RBMS group were significantly lower than that in the CBMS group since the second month (p < 0·05). The technical success rates of stent placement were 100% in both groups. The median survival in the RBMS group was significantly longer than that in the CBMS group (170 days vs. 123 days, p < 0·05). There was no significant difference in the incidence of complications between the two groups (p < 0·05).

Conclusions

The placement of RBMS in patients with inoperable malignant airway obstruction is feasible and safe, and it significantly reduces restenosis and improves overall survival compared with the placement of CBMS.

•

The baseline stenosis was immediately relieved in both groups after stent placement.

•

The stenosis grades in the RBMS group were significantly lower than that in the CBMS group since the second month.

•

The technical success rates of stent placement were 100% in both groups.

•

The median survival in the RBMS group was significantly longer than that in the CBMS group.

•

There was no significant difference of the incidence of complications between the two groups.

Malignant airway obstruction (MAO) is a serious situation of 20-30% cases of lung cancer, resulting in dyspnea, decreased functional status, and asphyxiation risk. Conventional stent placement provides immediate palliation of dyspnea. However, stent restenosis occurs during the follow up. A novel radioactive bare metal stent (RBMS) loaded with ¹²⁵I seed was developed for preventing such restenosis. Our study showed that placement of RBMS in patients with inoperable malignant airway obstruction is feasible and safe, and it significantly reduces the restenosis and improves overall survival compared with placement of conventional stent.

Side effects of CT-guided implantation of 125I seeds for recurrent malignant tumors of the head and neck assisted by 3D printing non co-planar template

BACKGROUND

For the recurrence of head and neck cancer after operation and radiotherapy, the local control of radioactive seed implantation is good, and it has a certain palliative effect. This study aims to investigate the acute and late side effects of a three-dimentional printing non co-planar template (3D-PNCT) for computed tomography (CT)-guided radioactive 125I seed (RIS) implantation in recurrent cancer of the head and neck.

METHODS

Between January 2016 and December 2016, forty-two patients with local recurrent malignant tumors of the head and neck received 3D-PNCT-assisted RIS implantation. The prescribed dose was 110-160 Gy. Preoperative planning design, production of individual guide plates, RIS implantation, postoperative dose evaluation, and follow-up were completed for all patients. Side effects in the skin, mucous membranes, blood and spinal cord were evaluated.

RESULTS

All patients underwent surgery successfully. Duration of follow-up was 4-14 (median, of 8.5) months. The activity of a single RIS was 0.34-0.7 (median, 0.6) mCi. The number of RIS was 10-126 (median, 34). The number of implantation needles was 4-31 (median, 11). The mean D2cc (dose to the most exposed 2-cc volume) and D0.1cc (dose to the most exposed 0.1-cc volume) of the skin were 24.9 (7.1-85.5) and 47.5 (9.4-167.2), respectively, whereas those of the spinal cord were 8.4 (4.5-33.3) and 14.2 (13.6-63.0), mucosa were 35.1 (4.2-82.8) and 87.0 (6.6-214.1), parotid glands were 16.2 (12.8-19.7) and 29.8 (26.1-33.4) and those of the trachea were 17.9 (2.5-45.9) and 32.7 (3.9-83.9), respectively. No case had an acute reaction of grade ≥ 3. Three cases had a grade-1 skin reaction. Blood toxicity did not occur, nor spinal-cord injury. Xerostomia was not aggravated than that of before brachytherapy. One case had a grade-3 nerve response.

CONCLUSIONS

3D-PNCT-assisted RIS implantation can provide good accuracy for positioning. For local recurrent malignant tumor of head and neck, there were no obvious adverse reactions.

Functionalized Selenium Nanosystem as Radiation Sensitizer of 125I Seeds for Precise Cancer Therapy

Although radiotherapy has been extensively applied in cancer treatment, external beam radiation therapy is still unable to avoid damage to adjacent normal tissues in the process of delivering a sufficient radiation dose to the tumor sites of patients. To overcome this limitation, chemoradiotherapy, as a combination of chemotherapy and radiotherapy of a radioactive seed, has been proposed to decrease the damage to tumor-surrounding tissues and enhance the radiosensitivity of solid tumors. In this study, we designed and synthesized folic acid-conjugated selenium nanoparticles (FA@SeNPs) as a cancer-targeting agent that could be synergistically enhanced by radioactive ¹²⁵I seeds to realize anticancer efficacy and inhibited colony formation ability. Interestingly, when compared with X-ray irradiation, ¹²⁵I seeds demonstrate a larger synergistic effect with the FA@SeNPs, drastically increasing reactive oxygen species overproduction to trigger apoptosis and influencing the cell cycle distribution in human breast cancer cells, inducing DNA damage and activating the mitogen-activated protein kinase and p53 signaling pathways. Moreover, this combination treatment demonstrates better in vivo antitumor activity and lower systemic toxicity. Therefore, this study demonstrates a new strategy for using functionalized SeNPs as a radiation sensitizer for ¹²⁵I seeds for cancer therapy.

Dosimetry Verification of 125I Seeds Implantation With Three-Dimensional Printing Noncoplanar Templates and CT Guidance for Paravertebral/Retroperitoneal Malignant Tumors

OBJECTIVE

To compare dose distributions of postoperative plans with preoperative plans for radioactive seed implantation of paravertebral/retroperitoneal tumors assisted by 3-dimensional printing noncoplanar templates and computed tomography.

METHODS

Sixteen patients with paravertebral/retroperitoneal tumors (21 lesions) underwent radioactive seed implantation with 3-dimensional printing noncoplanar templates. Prescribed dose was 110 to 160 Gy. We compared the dose distribution of the postoperative plan with the preoperative plan. Dose parameters were D90, minimum peripheral dose, V100, V150, conformal index and external index of the target volume, and the dose received by 2 cm³ of normal tissue of organs at risk (spinal cord, aorta, and kidney).

RESULTS

Sixteen 3-dimensional printing noncoplanar templates were produced for 21 treatment areas. Mean gross tumor volume (preoperative) of patients was 61.1 cm³, mean needle number was 17, mean number of implanted ¹²⁵I seeds was 65, and mean D90 of postoperative target area (gross tumor volume) was 131.1 Gy. Actual number of seeds postbrachytherapy increased by 1 to 12 in 8 cases. For postoperative plans, the mean D90, minimum peripheral dose, V100, V150 was 131.1 Gy, 67.1 Gy, 90.2%, and 64.1%, respectively, and 135.0 Gy, 64.7 Gy, 90.9%, and 64.1%, respectively, in preoperative plans. Comparing with the preplanned cases, the dose of the target volume was slightly lower and the high-dose area of the target volume was larger in postoperative cases, but the difference was not statistically significant (P > .05). Actual dose conformity of the target volume was lower than preplanned, and the difference was statistically significant (P = .005).

CONCLUSION

Three-dimensional printing noncoplanar templates can provide good accuracy for positioning and direction in radioactive seed implantation.

Computed tomography-guided implantation of 125I seeds brachytherapy for recurrent multiple pulmonary oligometastases: initial experience and results

Purpose

To retrospectively evaluate the efficacy and safety of computed tomography (CT)-guided percutaneous interstitial brachytherapy using ¹²⁵I radioactive seeds for multiple pulmonary metastatic tumors.

Material and methods

Between September 2013 and December 2015, 22 patients with multiple pulmonary metastases, who after conventional chemotherapy and trans-arterial chemoembolization (TACE) therapy were considered unable to withstand stereotactic body radiation therapy (SBRT), received CT-guided ¹²⁵I brachytherapy. Clinical data were studied retrospectively. A planning target volume of 90% (D₉₀) was 120-160 Gy for ¹²⁵I seeds with an activity of 25.9 MBq. A CT-based evaluation performed 1, 2, and 6 months’ post-implantation enabled review of local control of tumors.

Results

Twenty-two patients with 65 pulmonary metastases successfully completed treatment. The mean value for D₉₀ for implantation for ¹²⁵I seeds was 132 Gy. Complete response (CR) + partial response (PR) was documented in 81.54%, 78.46%, and 78.46% of patients at 1, 2, and 6 months after implantation, respectively. Fourteen out of 22 patients had CR, 3 had PR, 2 had stable disease (SD), and 3 had progressive disease (PD). Most of the metastases (CR + PR + SD; 87.69% after 6 months) were controlled by implantation.

Conclusions

CT-guided ¹²⁵I brachytherapy is a safe and effective treatment for multiple pulmonary metastatic tumors, and can achieve good short-term local control, so long as the radiation dose is sufficient.

125I seed irradiation induces apoptosis and inhibits angiogenesis by decreasing HIF-1α and VEGF expression in lung carcinoma xenografts

The purpose of this study was to examine the effects of irradiation by 125I seeds in human lung cancer xenograft model and to determine the underlying mechanisms involved, with a focus on angiogenesis. A group of 40 mice bearing A549 lung adenocarcinoma xenografts was randomly separated into 4 groups: control group (n=10), sham seed (0 mCi) implant group (n=10), 125I seed (0.6 mCi) implant group (n=10) and 125I seed (0.8 mCi) implant group (n=10), respectively. The body weight and tumor volume, were recorded every four days until the end of the study. At 30 days after irradiation, the microvessel density, proliferative index and apoptotic index were evaluated by quantitative morphometric analysis of the expression of CD34, proliferating cell nuclear antigen (Ki-67) and in situ terminal transferase-mediated fluorescein deoxy- UTP nick-end labeling (TUNEL), respectively. The changes in the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were detected by real-time PCR and western blot analysis. Consequently, 125I seed irradiation suppressed the growth of lung cancer xenografts in nude mice, while inhibiting cell proliferation and angiogenesis and inducing apoptosis as demonstrated by Ki67, CD34 and TUNEL staining. HIF-1α and VEGF mRNA and protein expression levels were substantially downregulated following 125I seed irradiation. Collectively, our data suggest that irradiation by 125I seeds is a promising new option for lung cancer treatment.

125I brachytherapy of locally advanced non-small-cell lung cancer after one cycle of first-line chemotherapy: a comparison with best supportive care

OBJECTIVES

The objective of this study was to assess the efficacy of computed tomography (CT)-guided ¹²⁵I brachytherapy alone in improving the survival and quality of life of patients with unresectable locally advanced non-small-cell lung cancer (NSCLC) after one cycle of first-line chemotherapy.

PATIENTS AND METHODS

Sixteen patients with locally advanced NSCLC were treated with CT-guided ¹²⁵I brachytherapy after one cycle of first-line chemotherapy (group A). Sixteen patients who received only best supportive care (group B) were matched up with the patients in group A. Primary end point included survival, and secondary end point included assessment of safety, effectiveness of CT-guided ¹²⁵I brachytherapy, and improvement in the quality of life.

RESULTS

The two groups were well balanced in terms of age, disease histology, tumor stage, tumor location, and performance status (P>0.05). The median follow-up time was 16 months (range, 3-30). The total tumor response rate was 75.0% in group A, which was significantly higher than that in group B (0.0%) (P<0.01). The median progression-free survival time was 4.80 months for patients in group A and 1.35 months for patients in group B (P<0.001). Kaplan-Meier survival analysis showed that the median survival time of group A was 9.4±0.3 months versus 8.4±0.1 months in group B (P=0.013). Tumor-related symptoms of patients were significantly relieved, and the quality of life was markedly improved in group A than in group B.

CONCLUSION

CT-guided ¹²⁵I brachytherapy improved the survival of patients with locally advanced NSCLC and quality of life after one cycle of first-line chemotherapy compared with best supportive care.

The Protective Roles of ROS-Mediated Mitophagy on 125I Seeds Radiation Induced Cell Death in HCT116 Cells

For many unresectable carcinomas and locally recurrent cancers (LRC), ¹²⁵I seeds brachytherapy is a feasible, effective, and safe treatment. Several studies have shown that ¹²⁵I seeds radiation exerts anticancer activity by triggering DNA damage. However, recent evidence shows mitochondrial quality to be another crucial determinant of cell fate, with mitophagy playing a central role in this control mechanism. Herein, we found that ¹²⁵I seeds irradiation injured mitochondria, leading to significantly elevated mitochondrial and intracellular ROS (reactive oxygen species) levels in HCT116 cells. The accumulation of mitochondrial ROS increased the expression of HIF-1α and its target genes BINP3 and NIX (BINP3L), which subsequently triggered mitophagy. Importantly, ¹²⁵I seeds radiation induced mitophagy promoted cells survival and protected HCT116 cells from apoptosis. These results collectively indicated that ¹²⁵I seeds radiation triggered mitophagy by upregulating the level of ROS to promote cellular homeostasis and survival. The present study uncovered the critical role of mitophagy in modulating the sensitivity of tumor cells to radiation therapy and suggested that chemotherapy targeting on mitophagy might improve the efficiency of ¹²⁵I seeds radiation treatment, which might be of clinical significance in tumor therapy.

125I Seeds Radiation Induces Paraptosis-Like Cell Death via PI3K/AKT Signaling Pathway in HCT116 Cells

¹²⁵I seeds brachytherapy implantation has been extensively performed in unresectable and rerecurrent rectal carcinoma. Many studies on the cancer-killing activity of ¹²⁵I seeds radiation mainly focused on its ability to trigger apoptosis, which is the most well-known and dominant type of cell death induced by radiation. However our results showed some unique morphological features such as cell swelling, cytoplasmic vacuolation, and plasma membrane integrity, which is obviously different to apoptosis. In this study, clonogenic proliferation was carried out to assay survival fraction. Transmission electron microscopy was used to analyze ultrastructural and evaluate morphologic feature of HCT116 cells after exposure to ¹²⁵I seeds radiation. Immunofluorescence analysis was used to detect the origin of cytoplasmic vacuoles. Flow cytometry analysis was employed to detect the size and granularity of HCT116 cells. Western blot was performed to measure the protein level of AIP1, caspase-3, AKT, p-Akt (Thr308), p-Akt (Ser473), and β-actin. We found that ¹²⁵I seeds radiation activated PI3K/AKT signaling pathway and could trigger paraptosis-like cell death. Moreover, inhibitor of PI3K/AKT signaling pathway could inhibit paraptosis-like cell death induced by ¹²⁵I seeds radiation. Our data suggest that ¹²⁵I seeds radiation can induce paraptosis-like cell death via PI3K/AKT signaling pathway.

Dosimetry verification of radioactive seed implantation for malignant tumors assisted by 3D printing individual templates and CT guidance

OBJECTIVE

We compared the dose distributions of postoperative plans with preoperative plans for 3D printing template-assisted radioactive seed implantations.

METHODS

A total of 14 patients with malignant tumors enrolled in the study. The dose parameters included D90, minimum peripheral dose, V100, V150, and V200. The statistical method was the paired t-test.

RESULTS

There was no significant difference in P values between the two groups for all parameters except for V100.

CONCLUSIONS

The 3D printing guide template can provide good accuracy for radioactive seed implantation.

Influential Factors and Synergies for Radiation-Gene Therapy on Cancer

Radiation-gene therapy, a dual anticancer strategy of radiation therapy and gene therapy through connecting radiation-inducible regulatory sequence to therapeutic gene, leading to the gene being induced to express by radiation while radiotherapy is performed and finally resulting in a double synergistic antitumor effect of radiation and gene, has become one of hotspots in the field of cancer treatment in recent years. But under routine dose of radiation, especially in the hypoxia environment of solid tumor, it is difficult for this therapy to achieve desired effect because of low activity of radiation-inducible regulatory elements, low level and transient expression of target gene induced by radiation, inferior target specificity and poor biosecurity, and so on. Based on the problems existing in radiation-gene therapy, many efforts have been devoted to the curative effect improvement of radiation-gene therapy by various means to increase radiation sensitivity or enhance target gene expression and the expression's controllability. Among these synergistic techniques, gene circuit, hypoxic sensitization, and optimization of radiation-induced sequence exhibit a good application potential. This review provides the main influential factors to radiation-gene therapy on cancer and the synergistic techniques to improve the anticancer effect of radiation-gene therapy.

125I Brachytherapy in Locally Advanced Nonsmall Cell Lung Cancer After Progression of Concurrent Radiochemotherapy

To investigate the safety and effectiveness of computed tomography (CT)-guided I seed implantation for locally advanced nonsmall cell lung cancer (NSCLC) after progression of concurrent radiochemotherapy (CCRT).We reviewed 78 locally advanced NSCLC patients who had each one cycle of first-line CCRT but had progressive disease identified from January 2006 to February 2015 at our institution. A total of 37 patients with 44 lesions received CT-guided percutaneous I seed implantation and second-line chemotherapy (group A), while 41 with 41 lesions received second-line chemotherapy (group B).Patients in group A and B received a total of 37 and 41 first cycle of CCRT treatment. The median follow-up was 19 (range 3-36) months. After the second treatment, the total response rate (RR) in tumor response accounted for 63.6% in group A, which was significantly higher than that of group B (41.5%) (P = 0.033). The median progression-free survival time (PFST) was 8.00 ± 1.09 months and 5.00 ± 0.64 months in groups A and B (P = 0.011). The 1-, 2-, and 3-year overall survival (OS) rates for group A were 56.8%, 16.2%, and 2.7%, respectively. For group B, OS rates were 36.6%, 9.8%, and 2.4%, respectively. The median OS time was 14.00 ± 1.82 months and 10.00 ± 1.37 months for groups A and B, respectively (P = 0.059). Similar toxicity reactions were found in both groups. Tumor-related clinical symptoms were significantly reduced and the patients' quality of life was obviously improved.CT-guided I seed implantation proved to be potentially beneficial in treating localized advanced NSCLC; it achieved good local control rates and relieved clinical symptoms without increasing side effects.

A comparison of the biological effects of 125I seeds continuous low-dose-rate radiation and 60Co high-dose-rate gamma radiation on non-small cell lung cancer cells

Objectives

To compare the biological effects of ¹²⁵I seeds continuous low-dose-rate (CLDR) radiation and ⁶⁰Co γ-ray high-dose-rate (HDR) radiation on non-small cell lung cancer (NSCLC) cells.

Materials and Methods

A549, H1299 and BEAS-2B cells were exposed to ¹²⁵I seeds CLDR radiation or ⁶⁰Co γ-ray HDR radiation. The survival fraction was determined using a colony-forming assay. The cell cycle progression and apoptosis were detected by flow cytometry (FCM). The expression of the apoptosis-related proteins caspase-3, cleaved-caspase-3, PARP, cleaved-PARP, BAX and Bcl-2 were detected by western blot assay.

Results

After irradiation with ¹²⁵I seeds CLDR radiation, there was a lower survival fraction, more pronounced cell cycle arrest (G₁ arrest and G₂/M arrest in A549 and H1299 cells, respectively) and a higher apoptotic ratio for A549 and H1299 cells than after ⁶⁰Co γ-ray HDR radiation. Moreover, western blot assays revealed that ¹²⁵I seeds CLDR radiation remarkably up-regulated the expression of Bax, cleaved-caspase-3 and cleaved-PARP proteins and down-regulated the expression of Bcl-2 proteins in A549 and H1299 cells compared with ⁶⁰Co γ-ray HDR radiation. However, there was little change in the apoptotic ratio and expression of apoptosis-related proteins in normal BEAS-2B cells receiving the same treatment.

Conclusions

¹²⁵I seeds CLDR radiation led to remarkable growth inhibition of A549 and H1299 cells compared with ⁶⁰Co HDR γ-ray radiation; A549 cells were the most sensitive to radiation, followed by H1299 cells. In contrast, normal BEAS-2B cells were relatively radio-resistant. The imbalance of the Bcl-2/Bax ratio and the activation of caspase-3 and PARP proteins might play a key role in the anti-proliferative effects induced by ¹²⁵I seeds CLDR radiation, although other possibilities have not been excluded and will be investigated in future studies.