Effect of Survivin Down-Regulation by Egr1-Survivin shRNA Combined with Radiotherapy on Radiosensitivity of Esophageal Squamous Carcinoma / Efecto de la Regulación Negativa de Survivina por shRNA de Egr1-Survivina Combinado con Radioterapia sobre la Radiosensibilidad del Carcinoma Escamoso de Esófago

SUMMARY: This study is to investigate the effect of survivin down-regulation by Egr1-survivin shRNA combined with radiotherapy on the apoptosis and radiosensitivity of esophageal squamous cell carcinoma ECA109 and KYSE150 cells. ECA109 and KYSE150 cells were transfected with Egr1-survivin shRNA, and then treated with radiotherapy. After 24 h, the mRNA and protein levels of Egr1-survivin were detected by qPCR and Western-Blot. Cell cycle and apoptosis were detected by flow cytometry. Western blot also detected levels of cleavaged Caspase 3 and Caspase 9. YM155 was used as a positive control to inhibit survivin expression. The levels of survivin mRNA and protein in ECA109 and KYSE150 cells treated with Egr1-survivin shRNA combined with radiotherapy were significantly lower than those of the blank control group, the empty vector control group, and, the YM155 + radiotherapy group (P<0.05). Meanwhile, after survivin down-regulation, the ratio of G2 to S phase of ECA109 and KYSE150 cells increased significantly, leading to significant G2 and S phase arrest. Additionally, apoptosis of ECA109 and KYSE150 cells increased significantly (P <0.01). Further, protein levels of cleavaged Caspase 3 and Caspase 9 significantly increased in Egr1-survivin shRNA combined with radiotherapy group. Egr1-survivin shRNA combined with radiotherapy can down-regulate survivin expression, which further increases the apoptosis, and enhances the radiosensitivity of ECA109 and KYSE150 cells.

Este estudio tuvo como objetivo investigar el efecto de la regulación negativa de survivina por el shRNA de Egr1-survivina combinado con radioterapia sobre la apoptosis y la radiosensibilidad del carcinoma de células escamosas de esófago Células ECA109 y KYSE150. Las células ECA109 y KYSE150 se transfectaron con shRNA de survivina Egr1 y luego se trataron con radioterapia. Después de 24 h, los niveles de ARNm y proteína de Egr1-survivina se detectaron mediante qPCR y Western-Blot. El ciclo celular y la apoptosis se detectaron mediante citometría de flujo. La transferencia Western también detectó niveles de Caspasa 3 y Caspasa 9 escindidas. Se usó YM155 como control positivo para inhibir la expresión de survivina. Los niveles de ARNm y proteína de survivina en células ECA109 y KYSE150 tratadas con shRNA de survivina Egr1 combinado con radioterapia fueron significativamente más bajos que los del grupo control en blanco, el grupo control de vector vacío y el grupo de radioterapia YM155 + (P <0,05). Mientras tanto, después de la regulación negativa de survivina, la proporción entre las fases G2 y S de las células ECA109 y KYSE150 aumentó significativamente, lo que llevó a una detención significativa de las fases G2 y S. Además, la apoptosis de las células ECA109 y KYSE150 aumentó significativamente (P <0,01). Además, los niveles de proteína de Caspasa 3 y Caspasa 9 escindidas aumentaron significativamente en el shRNA de Egr1- survivina combinado con el grupo de radioterapia. El shRNA de survivina de Egr1 combinado con radioterapia puede regular negativamente la expresión de survivina, lo que aumenta aún más la apoptosis y mejora la radiosensibilidad de las células ECA109 y KYSE150.

miR-18a enhances the radiosensitivity of nasopharyngeal carcinoma cells through inducing autophagy / 中华耳鼻咽喉头颈外科杂志

Objective: To explore the impacts of miR-18a overexpression or depression on the radiosensitivities of nasopharyngeal carcinoma cell line CNE1 and CNE2 and underlying mechanisms. Methods: CNE1 and CNE2 were transfected with miR-18a mimics, inhibitor and the corresponding control vectors. qRT-PCR and western blot were used to determine the ataxia telangiectasia mutated (ATM) expressions in CNE1 and CNE2. CNE1 and CNE2 with stably expressing miR-18a and miR-18a siRNA were constructed. Methyl thiazolyl tetrazolium (MTT) assay was used to detect the impacts of the miR-18a overexpression or depression combined with irradiation on the cell growth. Flow cytometry was used to detect the cell apoptosis and cell cycle. Colony formation assay was used to evaluate the raodiosensitivities of cells. Acridine orange (AO) staining and western blot were used respectively to test the autophagy and the expressions of related proteins. Independent samples t test was used to compare the mean value between groups by using SPSS 16.0. Results: ATM mRNA was decreased significantly in CNE1 and CNE2 cells transfected with 100 or 200 nmol/L miR-18a mimics for 48 hours (CNE1: RQ=0.174±0.139 and 0.003±0.001, t=9.939 and 19 470.783;CNE2: RQ=0.024±0.008 and 0.019±0.012, t=270.230 and 137.746, respectively, all P<0.001). ATM proteins were also decreased after transfected with 100 or 200 nmol/L miR-18a mimics for 72 hours. While in the cells transfected with 100 and 200 nmol/L miR-18a inhibitor for 48 hours, the expressions of ATM mRNA were upregulated significantly (CNE1: RQ=9.419±2.495 and 2.500±1.063, t=-4.427 and -41.241; CNE2: RQ=7.210±0.171 and 115.875±15.805, t=-62.789 and -12.589, all P<0.05), and the expressions of ATM proteins increased after transfected for 72 hours. The growth of cells with miR-18a overexpression plus 4 Gy irradiation were obviously inhibited compared to that of cells with the 4Gy irradiation alone; while the growth of miR-18a-inhibited cells increased compared to that of cells with 4 Gy irradiation alone (all P<0.05). CNE1 transfected with 100 nmol/L miR-18a mimics plus 4 Gy irradiation showed the higher apoptosis rate than the cells with 4 Gy irradiation alone ((22.9±2.1)% vs. (16.3±1.0)%, t=-4.870, P<0.01). Compared to the cells with 4 Gy irradiation alone, miR-18a-overexpressed cells plus 4 Gy irradiation decreased their percentages in G1 phases ((20.2±3.0)% vs. (29.8±4.4)%, t=3.119) and G2/M phases ((21.5±0.9)% vs. (33.4±3.1)%, t=6.410, P<0.05 for both), and increased their percentages in S phases ((56.7±4.9)% vs. (36.8±6.4)%, t=-4.246, P<0.05), and these cells possessed less colony number after exposure to different doses of irradiation, more autophagy-lysosome number, and more expressions of LC3 proteins (all P<0.05). There were no significant differences in the expressions of p62 expressions between different groups of cells. Conclusion: Overexpression of miR-18a can enhance the radiosensitivities of NPC cells by targeting ATM to abrogate G1/S, G2/M arrest and to induce autophagy and apoptosis.

Oligomycin A promotes radioresistance in HT29 colorectal cancer cells and its mechanisms / 中南大学学报(医学版)

OBJECTIVES@#Radiotherapy is one of the main therapies for colorectal cancer, but radioresistance often leads to radiotherapy failure. To improve the radioresistance, we explore the effect of oligomycin A, the H@*METHODS@#The effects of different concentrations of oligomycin A on the survival rate and glycolysis of HT29 colorectal cancer cells at different time points were investigated via MTT and glycolysis assay. siRNA-PFK1 was synthesized in vitro and transfected into HT29 cells. The effects of oligomycin A on radiosensitivity of HT29 colorectal cancer cells were measured via MTT and colony formation assay. Western blotting was used to detect the effect of oligomycin A on the expression of glycolytic enzyme PFK1. We compared difference between the effects of siRNA-PFK1 group and oligomycin A combined with siRNA-PFK1 group on cell survival and glycolysis. After 4 Gy X-ray irradiation, the effects of cell survival and glycolysis between the siRNA-PFK1 group and the oligomycin A combined with siRNA-PFK1 group were compared.@*RESULTS@#Compared with the 0 μmol/L oligomycin A group, the cell survival rate of HT29 cells treated with 4 μmol/L oligomycin A was significantly increased (@*CONCLUSIONS@#Oligomycin A can promote the radioresistance of HT29 colorectal cancer cells, which may be related to up-regulation of the PFK1 expression and increase of cell glycolysis.

Effect of Mmu-circRNA_016901 on the Radiosensitivity of Bone Marrow Mesenchymal Stem Cells / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of mmu-circRNA_016901 on the regulation of radiation injury of bone marrow stem cells and its mechanism.@*METHODS@#Bone marrow stem cells were exposed to different dose of X-ray, then the expression level of mmu-circRNA_016901 in bone marrow cells treated with different doses of X-ray was detected. The luciferase reporter gene assay was used to confirm that miRNA1249-5p is the target of mmu-circRNA_016901, and RNA Binding Protein Immunoprecipitation was used to confirm that TGF-β3 is the targeted on miRNA1249-5p，the expression of TGF-β3 and cell proliferation were detected after the expression of mmu-circRNA_01690 was regulated.@*RESULTS@#When the irradiation dose＜6 Gy, there were significant difference in the expression of mmn-circRNA-016901 after the bone marrow mesenchymal stem cells were treated by different doses of irradiation, which showed a statistically significant (P＜0.05). The luciferase reporter gene detection and co-immunoprecipitation experiments confirmed that Mmu-circRNA_016901 could binds to miRNA1249-5p specifically, and overexpression of mmu-circRNA_016901 could regulate miRNA1249-5p negatively, which resulted in a significant increase in TGF-β3 expression and promoting of cell proliferation.@*CONCLUSION@#mmu-circRNA_016901 affects the expression of TGF-β3 through miRNA1249-5p, and thus participates in the regulation of the radiation damage mechanism of bone marrow mesenchymal stem cells.

Effects of ranibizumab and amfenac on the functional abilities and radiosensitivity of uveal melanoma cells / Efeitos do ranibizumabe e do amfenac nas habilidades funcionais e na radiossensibilidade de células de melanoma uveal

ABSTRACT Purpose: To evaluate the effects of ranibizumab and amfenac in human uveal melanoma cell lines and to explore the ability of these compounds to sensitize uveal melanoma cells to radiation therapy. Methods: The 92.1 human uveal melanoma cell line was cultured and subjected to the proposed treatment (ranibizumab, amfenac, and a combination of both). Proliferation, migration, and invasion assays of the 92.1 uveal melanoma cell line were assessed after pretreatment with ranibizumab (125 mg/mL), amfenac (150 nM), or a combination of both. In addition, proliferation rates were assessed after treatment with ranibizumab and amfenac, and the cells were subsequently exposed to various radiation doses (0, 4, and 8 Gy). Results: Proliferation assay: cells treated with a combination of ranibizumab and amfenac had lower proliferation rates than controls (p=0.016) and than those treated with only ranibizumab (p=0.033). Migration assay: a significantly lower migration rate was observed in cells treated with amfenac than the control (p=0.014) and than those treated with ranibizumab (p=0.044). Invasion assay: there were no significant differences among the studied groups. Irradiation exposure: in the 4 Gy dose group, there were no significant differences among any groups. In the 8 Gy dose group, treatment with ranibizumab, amfenac, and their combination prior to application of the 8 Gy radiation led to a marked reduction in proliferation rates (p=0.009, p=0.01, and p=0.034, respectively) compared with controls. Conclusion: Combination of ranibizumab and amfenac reduced the proliferation rate of uveal melanoma cells; however, only amfenac monotherapy significantly decreased cell migration. The radiosensitivity of the 92.1 uveal melanoma cell line increased following the administration of ranibizumab, amfenac, and their combination. Further investigation is warranted to determine if this is a viable pretreatment strategy to render large tumors amenable to radiotherapy.

RESUMO Objetivo: Avaliar os efeitos do ranibizumabe em associação com o amfenac nas células de melanoma uveal humano e explorar a capacidade desses compostos em sensibilizar as células de melanoma uveal à radioterapia. Métodos: Células de melanoma uveal humano do tipo 92.1 foram cultivadas e submetidas ao tratamento proposto (ranibizumabe, amfenac e a combinação de ambos). Ensaios de proliferação, migração e invasão com as células de melanoma uveal do tipo 92.1 foram avaliados após tratamento com ranibizumabe (125 mg/ml), amfenac (150 nM) e a combinação de ambos. Além disso, as taxas de proliferação foram avaliadas após tratamento com ranibizumabe e amfenac com subsequente exposição das células a diferentes doses de radiação (0 Gy, 4 Gy e 8 Gy). Resultados: Ensaio de proliferação: células tratadas com ranibizumabe e amfenac combinados apresentaram taxas de proliferação inferiores em comparação ao grupo controle (p=0,016), do que as tratadas apenas com ranibizumabe (p=0,033). Ensaio de migração: foi observada uma taxa de migração significativamente mais baixa nas células tratadas com amfenac do que no grupo controle (p=0,014) e do que nas tratadas com ranibizumabe (p=0,044). Ensaio de invasão: não houve diferenças significativas entre os grupos estudados. Exposição à irradiação: no grupo da dose de 4 Gy, não houve diferença significante entre os grupos. No grupo da dose de 8 Gy, o tratamento com ranibizumabe, afenac e sua combinação antes da aplicação da radiação de 8 Gy levou a uma redução acentuada nas taxas de proliferação (p=0,009, p=0,01 e p=0,034, respectivamente) em comparação aos grupos controle. Conclusão: A combinação de ranibizumabe e amfenac reduziu a taxa de proliferação das células de melanoma uveal; no entanto, apenas o amfenac diminuiu significativamente a migração celular. A radiossensibilidade das células de melanoma uveal do tipo 92.1 aumentou após a administração de ranibizumabe, amfenac e sua combinação. Mais investigações são necessárias para determinar se esta é uma estratégia de pré-tratamento viável para tornar grandes tumores passíveis de radioterapia.

Longitudinal Assessment of Intravoxel Incoherent Motion Diffusion Weighted Imaging in Evaluating the Radio-sensitivity of Nasopharyngeal Carcinoma Treated with Intensity-Modulated Radiation Therapy / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI)was evaluated regarding its ability to preliminarily predict the short-term treatment response of nasopharyngeal carcinoma (NPC) following intensity-modulated radiation therapy. MATERIALS AND METHODS: IVIM-DWI with 14 b-factors (0-1,000 sec/mm2) was performed with a 3T MR system on 47 consecutive NPCs before, during (end of the 5th, 10th, 15th, 20th, and 25th fractions), and after fractional radiotherapy. IVIM parametrics (D, f, and D*) were calculated and compared to the baseline and xth fraction. Patients were categorized into responders and non-responders after radiotherapy. IVIM parametrics were also compared between subgroups. RESULTS: After fractional radiations, the D (except D5 and D at the end of the 5th fraction) after radiations were larger than the baseline D0 (p < 0.05), and the post-radiation D* (except D*5 and D*10) were smaller than D*0 (p < 0.05). f0 was smaller than f5 and f10 (p < 0.001) but larger than fend (p < 0.05). Furthermore, greater D5, D10, D15, and f10 coupled with smaller f0, D*20, and D*25 were observed in responders than non-responders (all p < 0.01). Responders also presented larger ΔD10, Δf10, ΔD*20, and δD*20 than non-responders (p < 0.05). Receiver operating characteristic curve analysis indicated that the D5, D*20, and f10 could better differentiate responders from non-responders. CONCLUSION: IVIM-DWI could efficiently assess tumor treatment response to fractional radiotherapy and predict the radio-sensitivity for NPCs.

Effects of Shengmai Jianghuang San on intestinal flora in nude mice with radio resistant cells of nasopharyngeal carcinoma / 中国中药杂志

Modern pharmacological studies have shown that Shengmai San has the effects of enhancing immunity and improving blood circulation, and Curcumae Longae Rhizoma(Jianghuang) has anti-inflammatory, anti-cancer, anti-oxidation and other functions. Shengmai San combined with Jianghuang is a new research direction in the study of anti-tumor of traditional Chinese medicines. The main treatment for nasopharyngeal carcinoma is radiation therapy, but radiation therapy can cause a variety of side effects, and it also changes the composition of the intestinal flora. In this study, the 16 s rDNA sequencing platform was used to perform macro-sequence sequencing of the intestinal flora samples of nude mice bearing the veins of Shengmai Jianghuang San, and then the results of intestinal flora data were analyzed to investigate the effect of Shengmai Jianghuang San on tumors. The results showed that Shengmai Jianghuang San combined with irradiation could enhance the therapeutic effect of tumor treatment. Radiation therapy would reduce the total number and diversity of intestinal flora in nude mice, and also change the structure of the flora. Shengmai Jianghuang San could protect the diversity of colonies, and also partially restore the colony imbalance caused by irradiation. This study provides a research idea for Shengmai Jianghuang San as a sensitizing adjuvant for radiotherapy of nasopharyngeal carcinoma.

Disulfiram, a Re-positioned Aldehyde Dehydrogenase Inhibitor, Enhances Radiosensitivity of Human Glioblastoma Cells In Vitro / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Glioblastoma, the most common brain tumor in adults, has poor prognosis. The purpose of this study was to determine the effect of disulfiram (DSF), an aldehyde dehydrogenase inhibitor, on in vitro radiosensitivity of glioblastoma cells with different methylation status of O⁶-methylguanine-DNA methyltransferase (MGMT) promoter and the underlying mechanism of such effect. MATERIALS AND METHODS: Five human glioblastoma cells (U138MG, T98G, U251MG, U87MG, and U373MG) and one normal human astrocyte (NHA) cell were cultured and treated with DSF or 6MV X-rays (0, 2, 4, 6, and 8 Gy). For combined treatment, cells were treated with DSF before irradiation. Surviving fractions fit from cell survival based on colony forming ability. Apoptosis, DNA damage repair, and cell cycle distributionwere assayed bywestern blot for cleaved caspase-3, γH2AX staining, and flow cytometry, respectively. RESULTS: DSF induced radiosensitization in most of the glioblastoma cells, especially, in the cells with radioresistance as wildtype unmethylated promoter (MGMT-wt), but did not in normal NHA cell. DSF augmented or induced cleavage of caspase-3 in all cells after irradiation. DSF inhibited repair of radiation-induced DNA damage in MGMT-wt cells, but not in cells with methylated MGMT promoter. DSF abrogated radiation-induced G2/M arrest in T98G and U251MG cells. CONCLUSION: Radiosensitivity of glioblastoma cells were preferentially enhanced by pre-irradiation DSF treatment compared to normal cell, especially radioresistant cells such as MGMT-wt cells. Induction of apoptosis or inhibition of DNA damage repair may underlie DSF-induced radiosensitization. Clinical benefit of combining DSF with radiotherapy should be investigated in the future.

CCR6 Is a Predicting Biomarker of Radiosensitivity and Potential Target of Radiosensitization in Rectal Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This study aimed to explore the functions and mechanisms of C-C motif chemokine receptor 6 (CCR6), a gene associated with progression and metastasis of colorectal cancer (CRC), in radiosensitivity of rectal cancer (RC). MATERIALS AND METHODS: RNA sequencing and immunohistochemical analysis on CCR6 expression were performed in pretreatment tissues of RC patients exhibiting different therapeutic effects of radiotherapy. Colonogenic survival assay was conducted in different CRC cell lines to assess their radiosensitivity. And the impact of CCR6 expression on radiosensitivity was validated through RNA interference. The DNA damage repair (DDR) abilities of cell lines with different CCR6 expression were evaluated through immunofluorescence-based γH2AX quantification. RESULTS: The CCR6 mRNA level was higher in patients without pathologic complete remission (pCR) than in those with pCR (fold changed, 2.11; p=0.004). High-level expression of CCR6 protein was more common in the bad responders than in the good responders (76.3% vs. 37.5%, p < 0.001). The CRC cell lines with higher CCR6 expression (LoVo and sw480) appeared to be more radioresistant, compared with the sw620 cell line which had lower CCR6 expression. CCR6 knockdown made the LoVo cells more sensitive to ionizing radiation (sensitization enhancement ratio, 1.738; p < 0.001), and decreased their DDR efficiency. CONCLUSION: CCR6 might affect the RC radiosensitivity through DDR process. These findings supported CCR6 as a predicting biomarker of radiosensitivity and a potential target of radiosensitization for RC patients.

MicroRNA-153-3p enhances cell radiosensitivity by targeting BCL2 in human glioma

BACKGROUND: Glioma is the most prevalent malignant tumor in human central nervous systems. Recently, the development of resistance to radiotherapy in glioma patients markedly vitiates the therapy outcome. MiR-153-3p has been reported to be closely correlated with tumor progression, but its effect and molecular mechanism underlying radioresistance remains unclear in glioma. METHODS: The expression of miR-153-3p was determined in radioresistant glioma clinical specimens as well as glioma cell lines exposed to irradiation (IR) using quantitative real-time PCR. Cell viability, proliferation and apoptosis were then evaluated by MTT assay, colony formation assay, Flow cytometry analysis and caspase-3 activity assay in glioma cells (U87 and U251). Tumor forming was evaluated by nude mice model in vivo. TUNEL staining was used to detect cell apoptosis in nude mice model. The target genes of miR-153-3p were predicted and validated using integrated bioinformatics analysis and a luciferase reporter assay. RESULTS: Here, we found that miR-153-3p was down-regulated in radioresistant glioma clinical specimens as well as glioma cell lines (U87 and U251) exposed to IR. Enhanced expression of miR-153-3p promoted the radiosensitivity, promoted apoptosis and elevated caspase-3 activity in glioma cells in vitro, as well as the radiosensitivity in U251 cell mouse xenografs in vivo. Mechanically, B cell lymphoma-2 gene (BCL2) was identified as the direct and functional target of miR-153-3p. Moreover, restoration of BCL2 expression reversed miR-153-3p-induced increase of radiosensitivity, apoptosis and caspase-3 activity in U251 cells in vitro. In addition, clinical data indicated that the expression of miR-153-3p was significantly negatively associated with BCL2 in radioresistance of glioma samples. CONCLUSIONS: Our findings suggest that miR-153-3p is a potential target to enhance the effect of radiosensitivity on glioma cells, thus representing a new potential therapeutic target for glioma.

LncRNA HULC mediates radioresistance via autophagy in prostate cancer cells

Prostate cancer (PCa) is the second leading cause of cancer death in men. Irradiation is one of the available options for treatment of PCa, however, approximately 10-45% of PCa are resistant to irradiation. We aimed to explore the role of long non-coding RNA highly upregulated in liver cancer (HULC) in the sensitivity of PCa cells to irradiation. Survival rate, cell apoptosis, cycle, expressions of related proteins, and caspase-3 activity were assessed to explore the effects of HULC on sensitivity of PCa cells to irradiation. Expression of HULC in DU-145, PC3, LNCaP, and RWPE-1 cells was determined and the influence of HULC on DU-145 cells was explored. Then, PC3 cells aberrantly expressing HULC were implanted into NOD-SCID mice for tumor xenograft study. Changes of autophagy after aberrant expression of HULC in vivo and in vitro were tested. Furthermore, the interacted protein of HULC and involved signaling pathway were investigated. In PC3 and LNCaP cells under irradiation, survival rate and cell cycle were decreased and apoptosis was increased by HULC knockdown. HULC knockdown arrested PC3 cells at G0/G1 phase. DU-145 was sensitive to irradiation, and resistance to irradiation of DU-145 cells was enhanced by HULC overexpression. Moreover, HULC knockdown enhanced the sensitivity of PC3 xenografts to irradiation. HULC knockdown promoted autophagy through interaction with Beclin-1 and inhibition of mTOR, resulting in increased apoptosis. HULC knockdown improved sensitivity of PCa cells to irradiation both in vivo and in vitro. HULC suppressed Beclin-1 phosphorylation, thereby reduced autophagy, involving the mTOR pathway.

Natural radioprotectors and their impact on cancer drug discovery

Cancer is a complex multifaceted illness that affects different patients in discrete ways. For a number of cancers the use of chemotherapy has become standard practice. Chemotherapy is a use of cytostatic drugs to cure cancer. Cytostatic agents not only affect cancer cells but also affect the growth of normal cells; leading to side effects. Because of this, radiotherapy gained importance in treating cancer. Slaughtering of cancerous cells by radiotherapy depends on the radiosensitivity of the tumor cells. Efforts to improve the therapeutic ratio have resulted in the development of compounds that increase the radiosensitivity of tumor cells or protect the normal cells from the effects of radiation. Amifostine is the only chemical radioprotector approved by the US Food and Drug Administration (FDA), but due to its side effect and toxicity, use of this compound was also failed. Hence the use of herbal radioprotectors bearing pharmacological properties is concentrated due to their low toxicity and efficacy. Notably, in silico methods can expedite drug discovery process, to lessen the compounds with unfavorable pharmacological properties at an early stage of drug development. Hence a detailed perspective of these properties, in accordance with their prediction and measurement, are pivotal for a successful identification of radioprotectors by drug discovery process.

Active caspase-3 expression levels as bioindicator of individual radiosensitivity

ABSTRACT Several molecules and events involved in cell response to radiation-induced damage have been investigated towards a personalized radiotherapy. Considering the importance of active caspase-3 in the proteolytic cascade that ensures radiation-induced apoptosis execution, this research was designed to evaluate the expression levels of this protein as a bioindicator of individual radiosensitivity. Peripheral blood samples of 10 healthy individuals were gamma-irradiated (cobalt-60 source) with 1, 2 and 4 Gy (control: non-irradiated samples), and active caspase-3 expression levels were measured in lymphocytes, by flow cytometry, ex vivo and after different times of in vitro incubation (24, 48 and 72 hours). Short-term incubation of 24 h was the most adequate condition to evidence correlations between dose radiation and active caspase-3 expression. For each radiation dose, it was observed a significant inter-individual variation in active caspase-3 expression intensity, suggesting that this parameter may be suitable for evidence individual radiosensitivity. The methodology presented and discussed in this work may help to predict healthy tissues response to radiation exposure toward the better patient outcome.

Radioactive iodine-refractory differentiated thyroid cancer: an uncommon but challenging situation

ABSTRACT Radioiodine (RAI)-refractory thyroid cancer is an uncommon entity, occurring with an estimated incidence of 4-5 cases/year/million people. RAI refractoriness is more frequent in older patients, in those with large metastases, in poorly differentiated thyroid cancer, and in those tumors with high 18-fluordeoxyglucose uptake on PET/CT. These patients have a 10-year survival rate of less than 10%. In recent years, new therapeutic agents with molecular targets have become available, with multikinase inhibitors (MKIs) being the most investigated drugs. Two of these compounds, sorafenib and lenvatinib, have shown significant objective response rates and have significantly improved the progression-free survival in the two largest published prospective trials on MKI use. However, no overall survival benefit has been achieved yet. This is probably related to the crossover that occurs in most patients who progress on placebo treatment to the open treatment of these studies. In consequence, the challenge is to correctly identify which patients will benefit from these treatments. It is also crucial to understand the appropriate timing to initiate MKI treatment and when to stop it. The purpose of this article is to define RAI refractoriness, to summarize which therapies are available for this condition, and to review how to select patients who are suitable for them.

miR-22 suppresses tumorigenesis and improves radiosensitivity of breast cancer cells by targeting Sirt1

BACKGROUND: miR-22 has been shown to be frequently downregulated and act as a tumor suppressor in multiple cancers including breast cancers. However, the role of miR-22 in regulating the radioresistance of breast cancer cells, as well as its underlying mechanism is still not well understood. METHODS: The expressions of miR-22 and sirt1 at mRNA and protein levels were examined by qRT-PCR and Western Blot. The effects of miR-22 overexpression and sirt1 knockdown on cell viability, apoptosis, radiosensitivity, γ-H2AX foci formation were evaluated by CCK-8 assay, flow cytometry, colony formation assay, and γ-H2AX foci formation assay, respectively. Luciferase reporter assay and qRT-PCR analysis were performed to confirm the interaction between miR-22 and sirt1. RESULTS: miR-22 was downregulated and sirt1 was upregulated at both mRNA and protein levels in breast cancer cells. miR-22 overexpression or sirt1 knockdown significantly suppressed viability, induced apoptosis, reduced survival fraction, and increased the number of γ-H2AX foci in breast cancer cells. Sirt1 was identified as a target of miR-22 and miR-22 negatively regulated sirt1 expression. Ectopic expression of sirt1 dramatically reversed the inhibitory effect of miR-22 on cell viability and promotive effect on apoptotic rates and radiosensitivity in breast cancer cells. CONCLUSIONS: miR-22 suppresses tumorigenesis and improves radiosensitivity of breast cancer cells by targeting sirt1, providing a promising therapeutic target for breast cancer.

DNA Methyltransferase Gene Polymorphisms for Prediction of Radiation-Induced Skin Fibrosis after Treatment of Breast Cancer: A Multifactorial Genetic Approach / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This study was conducted to investigate the role of four polymorphic variants of DNA methyltransferase genes as risk factors for radiation-induced fibrosis in breast cancer patients. We also assessed their ability to improve prediction accuracy when combined with mitochondrial haplogroup H, which we previously found to be independently associated with a lower hazard of radiation-induced fibrosis. MATERIALS AND METHODS: DNMT1 rs2228611,DNMT3A rs1550117,DNMT3A rs7581217, and DNMT3B rs2424908 were genotyped by real-time polymerase chain reaction in 286 Italian breast cancer patients who received radiotherapy after breast conserving surgery. Subcutaneous fibrosis was scored according to the Late Effects of Normal Tissue–Subjective Objective Management Analytical (LENT-SOMA) scale. The discriminative accuracy of genetic models was assessed by the area under the receiver operating characteristic curves (AUC). RESULTS: Kaplan-Meier curves showed significant differences among DNMT1 rs2228611 genotypes in the cumulative incidence of grade ≥ 2 subcutaneous fibrosis (log-rank test p-value= 0.018). Multivariate Cox regression analysis revealed DNMT1 rs2228611 as an independent protective factor for moderate to severe radiation-induced fibrosis (GG vs. AA; hazard ratio, 0.26; 95% confidence interval [CI], 0.10 to 0.71; p=0.009). Adding DNMT1 rs2228611 to haplogroup H increased the discrimination accuracy (AUC) of the model from 0.595 (95% CI, 0.536 to 0.653) to 0.655 (95% CI, 0.597 to 0.710). CONCLUSION: DNMT1 rs2228611 may represent a determinant of radiation-induced fibrosis in breast cancer patients with promise for clinical usefulness in genetic-based predictive models.

A Case of Hodgkin Lymphoma Developed in an Ataxia-telangiectasia Patient / 임상소아혈액종양

Ataxia-telangiectasia (AT) is characterized by cerebellar ataxia, progressive immunodeficiency, radiation sensitivity, telangiectasia, and predisposition to malignancy. AT patients have a 100-fold increased risk for the development of lymphoid malignancies. It is important to consider AT in a child with pre-existing ataxia, or lymphoid malignancy that was diagnosed at a younger age than expected. This consideration avoids the confusion between ataxia development and toxicity from chemotherapy. Hodgkin's lymphoma (HL) is usually treated with chemotherapy and/or radiotherapy. Unfortunately, when treated with conventional doses of radiotherapy, AT patients invariably experience devastating necrosis of their normal tissues. Therefore, a new treatment protocol for patients with HL in AT must be established. In this paper, we report the case of an 8-year-old female patient with HL in AT who was treated with chemotherapy. This patient was also treated with brentuximab (which targets CD30) for salvage therapy after the disease progressed.

Retrospective growth kinetics and radiosensitivity analysis of various human xenograft models / 한국실험동물학회지

The purpose of this study was to delineate the various factors that affect the growth characteristics of human cancer xenografts in nude mice and to reveal the relationship between the growth characteristics and radiosensitivity. We retrospectively analyzed 390 xenografts comprising nine different human cancer lines grown in nude mice used in our institute between 2009 and 2015. Tumor growth rate (TGR) was calculated using exponential growth equations. The relationship between the TGR of xenografts and the proliferation of the cells in vitro was examined. Additionally, we examined the correlations between the surviving fractions of cells after 2 Gy irradiation in vitro and the response of the xenograft to radiation. The TGR of xenografts was positively related to the proliferation of the cells in vitro (r(P)=0.9714, p<0.0001), whereas it was independent of the histological type of the xenografts. Radiation-induced suppression of the growth rate (T/C%) of xenografts was positively related to the radiosensitivity of the cells in vitro (SF₂; r(P)=0.8684, p=0.0284) and TGR (r(P)=0.7623, p=0.0780). The proliferation of human cancer cells in vitro and the growth rate of xenografts were positively related. The radiosensitivity of cancer cells, as judged from the SF₂ values in vitro, and the radiation-induced suppression of xenograft growth were positively related. In conclusion, the growth rate of human xenografts was independent of histological type and origin of the cancer cells, and was positively related to the proliferation of the cancer cells in vitro.

miR-124 regulates radiosensitivity of colorectal cancer cells by targeting PRRX1 / 南方医科大学学报

<p><b>OBJECTIVE</b>To detect the expression of miR-124 in colorectal carcinoma (CRC) cells and tissue specimens and analyze its association with the radiosensitivity of the cells.</p><p><b>METHODS</b>The expression of miR-124 in CRC cell lines and tissues were detected using qRT-PCR. The effect of miR-124 in modulating cell radiosensitivity was assessed in CRC cells with miRNA-124 overexpression and miRNA-124 knockdown, and bioinformatics prediction and dual luciferase reporter system were employed to identify the direct target of miR-124.</p><p><b>RESULTS</b>s miR-124 expression was down-regulated in CRC cell lines and tissues. CRC cells over-expressing miR-124 showed an obviously enhanced radiosensitivity, whereas miR-124 knockdown resulted in a reduced radiosensitivity of the cells. Bioinformatics prediction and dual luciferase reporter system verified PRRX1 as a direct target of miR-124, which regulated the radiosensitivity of CRC cells by directly inhibiting PRRX1.</p><p><b>CONCLUSION</b>miR-124 can enhance the radiosensitivity of CRC cells by directly targeting PRRX1, which provides a target for improving the therapeutic effect of radiotherapy of CRC.</p>

FXYD-3 expression in relation to local recurrence of rectal cancer

PURPOSE: In a previous study, the transmembrane protein FXYD-3 was suggested as a biomarker for a lower survival rate and reduced radiosensitivity in rectal cancer patients receiving preoperative radiotherapy. The purpose of preoperative irradiation in rectal cancer is to reduce local recurrence. The aim of this study was to investigate the potential role of FXYD-3 as a biomarker for increased risk for local recurrence of rectal cancer. MATERIALS AND METHODS: FXYD-3 expression was immunohistochemically examined in surgical specimens from a cohort of patients with rectal cancer who developed local recurrence (n = 48). The cohort was compared to a matched control group without recurrence (n = 81). RESULTS: Weak FXYD-3 expression was found in 106/129 (82%) of the rectal tumors and strong expression in 23/129 (18%). There was no difference in the expression of FXYD-3 between the patients with local recurrence and the control group. Furthermore there was no difference in FXYD-3 expression and time to diagnosis of local recurrence between patients who received preoperative radiotherapy and those without. CONCLUSION: Previous findings indicated that FXYD-3 expression may be used as a marker of decreased sensitivity to radiotherapy or even overall survival. We were unable to confirm this in a cohort of rectal cancer patients who developed local recurrence.