Radiation Sensitivity Of Cells Research Articles

The regulatory effects of autophagy to the CNE2 cells radio-sensitization.

To investigate the effects of autophagy activator and autophagy inhibitor on the CNE2 radiation sensitivity of nasopharyngeal carcinoma cells. RNA interference technology was used to silence the atg5 gene and autophagy inhibition cell model was constructed. Rapamycin and chloroquine were treated respectively on cells with X-ray 5Gy irradiation. Cells' growth status were observed for 8 days and control group was set. The cell viability was detected by MTT assay and colony formation assay, and the cell cycle was analyzed by flow cytometry. Compared with the control group, the survival rate, clone formation rate and the survival rate of the irradiation of the other three groups were significantly lower. (P<0.05) Most cells were detected in the G0/G1 phase in the other three groups except the control group, and cells of the other two periods were less than those in the G0/G1 phase. The autophagy inhibitor or activator and atg5 silencing can be increased by CNE2 radiation therapy, however, the sensitization effect increase of autophagy activator is better than others.

Improved sensitization effect of sunitinib in cancer cells of the esophagus under hypoxic microenviroment.

Radiotherapy is widely used in esophageal squamous cell carcinoma (ESCC) treatment. Promoting the radiation sensitivity of cancer cells is required. Recent studies have shown that sunitinib can inhibit the growth of several cancer lines. However, few studies on the radiosensitive effect of sunitinib on ESCC cells under hypoxic conditions have been conducted. In the present study, the radiosensitive effects of sunitinib on human ESCC cells were assessed, and the underlying mechanisms were explored. ESCC cells were exposed to hypoxia and treated with sunitinib at different concentrations prior to irradiation. Sunitinib potently inhibited ESCC cell proliferation in an MTT assay. In a clonogenic survival assay, sunitinib sensitized hypoxic ESCC cells to radiation, with sensitizing enhancement ratios of 1.31-1.59. In addition, sunitinib promoted the apoptosis of ESCC cells, but did not alter their cell cycle distribution. Radiosensitization was accompanied by inhibition of the radiation-induced upregulation of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) expression. Thus, sunitinib confers radiosensitivity to esophageal cancer cells, which is associated with the downregulation of HIF-1α and VEGF expression. Sunitinib can be a promising radiosensitizer for esophageal cancer radiotherapy.

Human Papillomavirus (HPV) E7 Oncogene Mediated Squamous Cell Malignancy of the Oropharynx and Cervix in K14E7 Fancd2-/- Mice and Also Causes Hematopoietic Cell Radiation Sensitivity and Malignant B Cell Transformation

Human Papillomavirus (HPV) E7 Oncogene Mediated Squamous Cell Malignancy of the Oropharynx and Cervix in K14E7 Fancd2-/- Mice and Also Causes Hematopoietic Cell Radiation Sensitivity and Malignant B Cell Transformation

Bortezomib sensitizes esophageal squamous cancer cells to radiotherapy by suppressing the expression of HIF-1α and apoptosis proteins.

Radiation therapy is a typical treatment for esophageal squamous cell carcinoma (ESCC), especially middle and upper segment esophagus, and inoperable patients. However, how to promote radiation sensitivity in radio-resistant cancer cells is a conundrum. Here, our study investigated the radiosensitizing effect of bortezomib, a specific and reversible dipeptide boronic acid analog, in ESCC cells. Human esophageal squamous carcinoma cell lines Eca109 and TE-13 were exposed to hypoxia and/or ionizing radiation (IR) with or without treatment of bortezomib. Cell proliferation assay was performed with CCK8. Cell apoptosis and cell cycle assay were performed with flow cytometry. The radiosensitization effect of was assessed by clonogenic survival and progression of tumor xenograft. The expression of HIF-1α, VEGF, and apoptosis proteins was evaluated by Western blot. Radiation-induced DNA double strand break and homologous recombination repair were assessed by immunofluorescence. Our results show that bortezomib efficiently radiosensitizes ESCC cells by decreasing the expression of HIF- 1α and VEGF, inducing apoptosis by activating caspase, and delaying DNA damage repair after radiation.

Abstract 3539: Vitamin D/EB 1089 mediated radio-sensitization of lung cancer cells and head and neck cancer cells

Abstract Lung cancer is a principal factor contributing to cancer-related mortality in the United States. Patients with lung cancer generally have a poor prognosis and resection is often not possible. Our previous work has demonstrated that Vitamin D and its analog, EB1089 (EB), enhance radio sensitivity of H460 and A549 non-small cell lung cancer (NSCLC) cells (Sharma et al; A novel cytostatic form of autophagy in sensitization of non-small cell lung cancer cells to radiation by vitamin D and the vitamin D analog, EB 1089. Autophagy; 2014;10(12):2346-61). In this study, we have extended these findings of Vitamin D/EB 1089 induced radio-sensitization in multiple tumor cell lines such as Lewis Lung mouse non-small cell lung cancer cells (LLC), head and neck cancer cells (HN30) and a primary cell line established from a lung tumor obtained from a cancer patient. All cell lines were treated with multiple doses of radiation in the range of 2-6 Gy and EB1089 was used at concentration of 100nM. Sensitivity was determined based on viable cell number and clonogenic survival. We observed enhanced radiation sensitivity of LLC and HN30 cells with the combination treatment of radiation and EB1089. However, as reported previously by our laboratory (Sharma et al., 2014; Autophagy), sensitization was dependent on the presence of functional p53 and was not evident in HN6 head and neck tumor cells that are mutant in p53. These data suggest that Vitamin D or a Vitamin D analog could be used to enhance radiation sensitivity of various malignancies but only where the tumors express wild type p53. Furthermore, we were able to demonstrate sensitization in a primary cell line established from lung tumor tissues utilizing conditioned medium from stromal cells treated with EB1089. These data suggest that stromal re-programming of cancer cells could influence radiation sensitivity. In studies to define the signaling pathways associated with radiation sensitization, we also observed inactivation by EB 1089 of the NF-kB pathway that was activated by radiation alone in H460 and H1299 NSCLC cells. Silencing of AMPK attenuated radiation sensitization by EB 1089. Sensitization was accompanied by enhanced secretion of the autophagy/senescence related marker, HMGB1. Taken together, these studies indicate that Vitamin and/or its analogs enhance radiosensitivity by cellular pathways involving NF-kB and AMPK and that HMGB1 may be secreted to activate an immune response to the combination treatment. Citation Format: Theresa Thekkudan, Khushboo Sharma, Tareq Saleh, David Gewirtz. Vitamin D/EB 1089 mediated radio-sensitization of lung cancer cells and head and neck cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3539.

The Enhancement of Radiation Sensitivity in Nasopharyngeal Carcinoma Cells via Activation of the Rac1/NADPH Signaling Pathway.

We reported in an earlier study that using mass spectrometry and bioinformatic analysis demonstrated Rac1 protein might be mostly mitochondrial target in the radiosensitization process of nasopharyngeal carcinoma CNE-1 cells. The goal of our current study was to reveal the relationship between Rac1/NADPH pathway and radiosensitization in CNE-1 cells using Rac1 activator, phorbol 12-myristate 13-acetate (PMA) and Rac1 inhibitor NSC23766. The Rac1-GTP expression was determined using a pulldown assay, the Rac1 location using a immunofluorescence with a laser scanning confocal microscope, the NADPH oxidase activity with NBT assay and the reactive oxygen species with DCFH-DA probe. The apoptosis rate was analyzed by flow cytometry, and the expressions of p67(phox) and NFκB-p105/p50 were analyzed by Western blot. After treatment with PMA and 2 Gy radiation (compared to the control), Rac1-GTP was activated and translocated to the cell membrane. NADPH oxidase activity, reactive oxygen species of intracellular concentration and the apoptosis rate increased significantly. The expression of p67(phox) and NFκB-p50 protein also increased. However, in the cells treated with NSC23766 alone or NSC23766 combined with 2 Gy irradiation, the results were just the opposite. Overall, these results indicate that the Rac1 protein may be the key target involved in the radiosensitization of nasopharyngeal carcinoma cells. The activated Rac1/NADPH pathway combined with radiation can increase the radiosensitivity of nasopharyngeal carcinoma cells, and the Rac1/NADPH pathway may be the signaling pathway involved in the radiosensitization process.

Accumulation of RNA-dependent protein kinase (PKR) in the nuclei of lung cancer cells mediates radiation resistance.

We have previously demonstrated that radiation induced cell death in PKR (−/−) deficient mouse embryo fibroblasts (MEFs) but not in PKR (+/+) wild type MEFs. Our study indicated that PKR can also be involved in survival pathways following radiation therapy through activation of the AKT survival pathways in these MEFs is mediated in part through PKR. The role of PKR on radiation sensitivity in cancer cells has not been evaluated. In this study, we demonstrated that radiation treatment causes nuclear translocation of PKR in human lung cancer cells. The transduction of lung cancer cells with a dominant negative adenoviral PKR vector blocks nuclear translocation of PKR and leads to the reversal of radiation resistance. Plasmid transduction of lung cancer cells with nuclear targeted wild type PKR vectors also increased radiation resistance. This effect is selectively abrogated by plasmid transduction of dominant negative PKR vectors which restore radiation sensitivity. These findings suggest a novel role for PKR in lung cancer cells as a mediator of radiation resistance possibly through translocation of the protein product to the nucleus.

Synthesis of PEGylated Ferrocene Nanoconjugates as the Radiosensitizer of Cancer Cells.

Radiation is one of the most widely used methods for cancer diagnosis and therapy. Herein, we report a new type of radiation sensitizer (Fc-PEG) by a facile one-step reaction of conjugating the hydrophilic PEG chain with hydrophobic ferrocene molecule. The chemical composition and structure of Fc-PEG have been thoroughly characterized by FT-IR, NMR, GPC, and MALDI-TOF mass spectrometry. This Fc-PEG conjugate could self-assemble in aqueous solution into spherical aggregates, and it was found that the exposure to 4 Gy of X-ray radiation have little influence on the shape and size of these aggregates. After the chemical bonding with PEG chains, the uptake level of Fe element could be enhanced via the formation of aggregates. The live/dead, CCK-8, as well as apoptosis assays, indicated that the death of cancer cells can be obviously increased by X-ray radiation after the incubation of these Fc-based nanoconjugates, which might be served as the radiation sensitizer toward cancer cells. We suggest that this radiosensitizing effect comes from the enhancement of reactive oxygen specimen (ROS) level as denoted by both flow cytometric and fluorescence microscopic analysis. The enhanced radiation sensitivity of cancer cells is contributed by the synergic effect of Fe-induced radiation-sensitizing and the increased uptake of nanoconjugates after polymeric grafting.

Dual Targeting of Akt and mTORC1 Impairs Repair of DNA Double-Strand Breaks and Increases Radiation Sensitivity of Human Tumor Cells.

Inhibition of mammalian target of rapamycin-complex 1 (mTORC1) induces activation of Akt. Because Akt activity mediates the repair of ionizing radiation-induced DNA double-strand breaks (DNA-DSBs) and consequently the radioresistance of solid tumors, we investigated whether dual targeting of mTORC1 and Akt impairs DNA-DSB repair and induces radiosensitization. Combining mTORC1 inhibitor rapamycin with ionizing radiation in human non-small cell lung cancer (NSCLC) cells (H661, H460, SK-MES-1, HTB-182, A549) and in the breast cancer cell line MDA-MB-231 resulted in radiosensitization of H661 and H460 cells (responders), whereas only a very slight effect was observed in A549 cells, and no effect was observed in SK-MES-1, HTB-182 or MDA-MB-231 cells (non-responders). In responder cells, rapamycin treatment did not activate Akt1 phosphorylation, whereas in non-responders, rapamycin mediated PI3K-dependent Akt activity. Molecular targeting of Akt by Akt inhibitor MK2206 or knockdown of Akt1 led to a rapamycin-induced radiosensitization of non-responder cells. Compared to the single targeting of Akt, the dual targeting of mTORC1 and Akt1 markedly enhanced the frequency of residual DNA-DSBs by inhibiting the non-homologous end joining repair pathway and increased radiation sensitivity. Together, lack of radiosensitization induced by rapamycin was associated with rapamycin-mediated Akt1 activation. Thus, dual targeting of mTORC1 and Akt1 inhibits repair of DNA-DSB leading to radiosensitization of solid tumor cells.

SP-0100: Radiation sensitivity of human skin stem cells : dissecting epigenetic effects of radiation

SP-0100: Radiation sensitivity of human skin stem cells : dissecting epigenetic effects of radiation

SP-0101: A radiation systems biology view of radiation sensitivity of normal and tumour cells

SP-0101: A radiation systems biology view of radiation sensitivity of normal and tumour cells

Enhancement of Radiation Sensitivity in Lung Cancer Cells by a Novel Small Molecule Inhibitor That Targets the β-Catenin/Tcf4 Interaction.

Radiation therapy is an important treatment choice for unresectable advanced human lung cancers, and a critical adjuvant treatment for surgery. However, radiation as a lung cancer treatment remains far from satisfactory due to problems associated with radiation resistance in cancer cells and severe cytotoxicity to non-cancer cells, which arise at doses typically administered to patients. We have recently identified a promising novel inhibitor of β-catenin/Tcf4 interaction, named BC-23 (C21H14ClN3O4S), which acts as a potent cell death enhancer when used in combination with radiation. Sequential exposure of human p53-null non-small cell lung cancer (NSCLC) H1299 cells to low doses of x-ray radiation, followed 1 hour later by administration of minimally cytotoxic concentrations of BC-23, resulted in a highly synergistic induction of clonogenic cell death (combination index <1.0). Co-treatment with BC-23 at low concentrations effectively inhibits Wnt/β-catenin signaling and down-regulates c-Myc and cyclin D1 expression. S phase arrest and ROS generation are also involved in the enhancement of radiation effectiveness mediated by BC-23. BC-23 therefore represents a promising new class of radiation enhancer.

Autophagic flux in glioblastoma cells

To establish metabolic context for radiation sensitivity by measuring autophagic flux in two different glioblastoma (GBM) cell lines. Clonogenic survival curve analysis of U87 or U251 cells exposed to γ radiation, fast neutrons, a mixed energy neutron beam (METNB) or Auger electrons from a gadolinium neutron capture (GdNC) reaction suggested other factors, beyond a defective DNA damage response, contribute to cell death of U251 cells. Altered tumor metabolism (autophagy) was hypothesized as a factor in U251 cells’ clonogenic response. Each of the four different radiation modalities induced an increase in the number of autophagosomes in both U87 and U251 cells. Changes in the number of autophagosomes can be explained by either induction of autophagy or alterations in autophagic flux so autophagic flux was assayed by p62 immunoblotting or in engineered GBM cells that stably express an autophagy marker protein, LC3B-eGFP-mCherry. Perturbations in later stages of autophagy in U251 cells corresponded with radiation sensitivity of U251 cells irradiated with 10 Gy γ rays. Establishment of altered autophagic flux is a useful biomarker for metabolic stress and provided metabolic context for radiation sensitization to 10 Gy γ rays. These results provide strong evidence for the usefulness of managing tumor cell metabolism as a tool for the enhancement of radiation therapy.

PTEN deficiency promotes macrophage infiltration and hypersensitivity of prostate cancer to IAP antagonist/radiation combination therapy.

PTEN loss is prognostic for patient relapse post-radiotherapy in prostate cancer (CaP). Infiltration of tumor-associated macrophages (TAMs) is associated with reduced disease-free survival following radical prostatectomy. However, the association between PTEN loss, TAM infiltration and radiotherapy response of CaP cells remains to be evaluated. Immunohistochemical and molecular analysis of surgically-resected Gleason 7 tumors confirmed that PTEN loss correlated with increased CXCL8 expression and macrophage infiltration. However PTEN status had no discernable correlation with expression of other inflammatory markers by CaP cells, including TNF-α. In vitro, exposure to conditioned media harvested from irradiated PTEN null CaP cells induced chemotaxis of macrophage-like THP-1 cells, a response partially attenuated by CXCL8 inhibition. Co-culture with THP-1 cells resulted in a modest reduction in the radio-sensitivity of DU145 cells. Cytokine profiling revealed constitutive secretion of TNF-α from CaP cells irrespective of PTEN status and IR-induced TNF-α secretion from THP-1 cells. THP-1-derived TNF-α increased NFκB pro-survival activity and elevated expression of anti-apoptotic proteins including cellular inhibitor of apoptosis protein-1 (cIAP-1) in CaP cells, which could be attenuated by pre-treatment with a TNF-α neutralizing antibody. Treatment with a novel IAP antagonist, AT-IAP, decreased basal and TNF-α-induced cIAP-1 expression in CaP cells, switched TNF-α signaling from pro-survival to pro-apoptotic and increased radiation sensitivity of CaP cells in co-culture with THP-1 cells. We conclude that targeting cIAP-1 can overcome apoptosis resistance of CaP cells and is an ideal approach to exploit high TNF-α signals within the TAM-rich microenvironment of PTEN-deficient CaP cells to enhance response to radiotherapy.

Involvement of Non-coding RNAs in Chemo- and Radioresistance of Colorectal Cancer.

Despite recent progress in understanding the cancer signaling pathways and in developing new therapeutic strategies, however, the resistance of colorectal cancer (CRC) cells to chemo- and radiotherapy represents the main hurdle to the successful treatment, leading to tumor recurrence and, consequently, a poor prognosis. Therefore, overcoming drug and radiation resistance, enhancing drug and radiation sensitivity of CRC cells, and improving the efficacy of chemo- and radiotherapy have an important significance in the treatment of CRC. The identification of new molecular biomarkers which can predict therapy response and prognosis is one of the most significant aims in pharmacogenomics and cancer research.Recent studies showed that non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), may play important roles in the regulation of chemo- and radioresistance of CRC, by controlling several signaling pathways, including cell cycle, proliferation, apoptosis and DNA damage repair. Recent data have demonstrated that selective modulation of the ncRNA activity can improve the response to chemo- and radiotherapy, providing an innovative anti-tumor approach based on a ncRNA-related gene therapy. Therefore, ncRNAs could not only be useful as predictive and prognostic biomarkers but also serve as targets for the development of novel therapeutic strategies to overcome drug and radiation resistance in CRC. In this chapter, we discuss the involvement of ncRNAs in chemo- and radiotherapy resistance of CRC, highlighting the impact of these molecules in prediction of the treatment response and modification of the therapy, and describing possible intracellular pathways involved in these processes.

MiR-124 radiosensitizes human esophageal cancer cell TE-1 by targeting CDK4.

Radiotherapy is one of the most important treatments for esophageal cancer, but radioresistance remains a major challenge. Previous studies have shown that microRNAs (miRNAs or miRs) are involved in human cancers. miR-124 has been widely reported in various cancers and it is intimately involved in proliferation, cell cycle regulation, apoptosis, migration, and invasion of cancer cells. The aim of this study was to explore the relationship between the miR-124/cyclin-dependent kinase 4 (CDK4) axis and the radiosensitivity of esophageal cancer cells. In this study, we identified the reduced expression of miR-124 in 18 paired esophageal cancer tissues compared to their matched normal tissues. In order to investigate the physiological role of miR-124 in esophageal cancer, the cell counting kit-8 (CCK-8) assay and wound healing assay were performed, and the results suggest that miR-124 overexpression decreases tumor growth and aggression. Next, we detected the effects of ectopic miR-124 expression on the apoptosis of an esophageal cancer cell line (TE-1) following radiotherapy. Using the CCK-8 assay and Hoechst 332528 stain, we found that ectopic expression of miR-124 led to a higher percentage of apoptotic cells. Finally, we identified that CDK4 is a direct target of miR-124 in TE-1 cells using target prediction algorithms and a luciferase reporter assay. Moreover, western blot assay confirmed that CDK4 was downregulated during miR-124 transfection. Taken together, we illustrate that the miR-124/CDK4 axis plays an important role in radiation sensitivity of human esophageal cancer cells by targeting CDK4.

Effect of β-catenin silencing in overcoming radioresistance of head and neck cancer cells by antagonizing the effects of AMPK on Ku70/Ku80.

We attempted to elucidate the mechanism of cell death after radiation by studying how β-catenin silencing controls the radiation sensitivity of radioresistant head and neck cancer cells. The most radioresistant cancer cell line (AMC-HN-9) was selected for study. Targeted silencing of β-catenin was used on siRNAs. Sensitivity to radiation was examined using clonogenic and methylthiazol tetrazolium (MTT) assays. A combination of irradiation plus β-catenin silencing led to a significant reduction in the inherent radioresistance of AMC-HN-9 cells. Although expression of Ku70/80 was upregulated in AMC-HN-9 cells after irradiation, Ku70/80 was dramatically decreased in a combination of irradiation and β-catenin silencing. Interestingly, irradiation-induced Ku70/80 was completely prevented by β-catenin silencing-induced LKB1/AMP-activated protein kinase (LKB1/AMPK) signal. The LKB1/AMPK pathway might relay the signal between the Wnt/β-catenin pathway and the Ku70/Ku80 DNA repair machinery, and play a decisive role in fine-tuning the responses of cancer cells to irradiation. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1909-E1917, 2016.

Inhibition of cyclin D1 enhances sensitivity to radiotherapy and reverses epithelial to mesenchymal transition for esophageal cancer cells.

Acquired radioresistance during radiotherapy has significantly affected the treatment efficacy in esophageal cancer. Many of radioresistant cancer cells demonstrated epithelial-mesenchymal transition (EMT).We found in previous study that a radioresistant cell line (KYSE-150R) possessed EMT characteristic with cyclin D1 overexpression. Cyclin D1 has been demonstrated to affect the radiation sensitivity in cancer cells. To elucidate the molecular functions of cyclin D1 on EMT phenotypes and esophageal cancer radiosensitivity, we treated the radioresistant esophageal cancer cells (KYSE-150R) and parental cells (KYSE-150) with cyclin D1 small interfering RNA (siRNA). The cell proliferation rate of KYSE-150R and the radiation survival fraction were significantly decreased in cyclin D1 siRNA treatment group. Knocking down cyclin D1 resulted in G0/G1 arrest in KYSE-150R cells. The average number of irradiation-induced γ-H2AX foci increased in the cells treated with cyclin D1 siRNA, indicating impaired DNA double-strand break (DSB) repair in KYSE-150R cells. Cyclin D1 also reversed EMT phenotypes with significantly increased expression of E-cadherin in KYSE-150R cells. However, cyclin D1 siRNA have no radiosensitizing effects on KYSE-150 cells, with no obvious change in EMT marker expression .Our work showed that EMT phenotypes can be reduced and the radiosensitivity of esophageal cancer cells can be enhanced by inhibiting cyclin D1.

TP53inp1 Gene Is Implicated in Early Radiation Response in Human Fibroblast Cells.

Tumor protein 53-induced nuclear protein-1 (TP53inp1) is expressed by activation via p53 and p73. The purpose of our study was to investigate the role of TP53inp1 in response of fibroblasts to ionizing radiation. γ-Ray radiation dose-dependently induces the expression of TP53inp1 in human immortalized fibroblast (F11hT) cells. Stable silencing of TP53inp1 was done via lentiviral transfection of shRNA in F11hT cells. After irradiation the clonogenic survival of TP53inp1 knockdown (F11hT-shTP) cells was compared to cells transfected with non-targeting (NT) shRNA. Radiation-induced senescence was measured by SA-β-Gal staining and autophagy was detected by Acridine Orange dye and microtubule-associated protein-1 light chain 3 (LC3B) immunostaining. The expression of TP53inp1, GDF-15, and CDKN1A and alterations in radiation induced mitochondrial DNA deletions were evaluated by qPCR. TP53inp1 was required for radiation (IR) induced maximal elevation of CDKN1A and GDF-15 expressions. Mitochondrial DNA deletions were increased and autophagy was deregulated following irradiation in the absence of TP53inp1. Finally, we showed that silencing of TP53inp1 enhances the radiation sensitivity of fibroblast cells. These data suggest functional roles for TP53inp1 in radiation-induced autophagy and survival. Taken together, we suppose that silencing of TP53inp1 leads radiation induced autophagy impairment and induces accumulation of damaged mitochondria in primary human fibroblasts.

Modulation of Endothelial Cell Radiation Sensitivity and Lung Tumor Response to Radiation Therapy

Modulation of Endothelial Cell Radiation Sensitivity and Lung Tumor Response to Radiation Therapy