OBJECTIVETo investigate the effect of curcumin (Cur) on radiosensitivity of nasopharyngeal carcinoma cell CNE-2 and its mechanism.

METHODThe effect of curcumin on radiosensitivity was determined by the clone formation assay. The cell survival curve was fitted by Graph prism 6. 0. The changes in cell cycle were analyzed by flow cytometry (FCM). The differential expression of long non-coding RNA was detected by gene chip technology. Part of differentially expressed genes was verified by Real-time PCR.

RESULTAfter 10 micro mol L-1 Cur had worked for 24 h, its sensitization enhancement ratio was 1. 03, indicating that low concentration of curcumin could increase the radiosensitivity of nasopharyngeal carcinoma cells; FCM displayed a significant increase of G2 phase cells and significant decrease of S phase cells in the Cur combined radiation group. In the Cur group, the GUCY2GP, H2BFXP, LINC00623 IncRNA were significantly up-regulated and ZRANB2-AS2 LOC100506835, FLJ36000 IncRNA were significantly down-regulated.

CONCLUSIONCur has radiosensitizing effect on human nasopharyngeal carcinoma CNE-2 cells. Its mechanism may be related to the changes in the cell cycle distribution and the expression of long non-coding IncRNA.

Cell Cycle ; drug effects ; radiation effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; radiation effects ; Curcumin ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; radiation effects ; Humans ; RNA, Long Noncoding ; genetics ; Radiation Tolerance ; drug effects

OBJECTIVETo study genome-wide gene expression changes in gastric cancer cells after iodine-125 ¹²⁵(I) particle irradiation.

METHODS¹²⁵I particles were used to irradiate three gastric cancer cell lines of various differentiation levels:high (BGC-823) , medium (AGS) and low (NCI-N87) .Whole-genome gene expression was investigated with microarray. The gene expression in iodine-125 irradiated and untreated cancer cells was compared, and the genes with transcript levels altered for at least 2 folds (P < 0.05) were selected. The change in gene expression levels was verified by using quantitative real-time (qRT) -PCR.

RESULTSThe three gastric cancer cell lines received the same dose rate of ¹²⁵I particle irradiation. Cluster analysis showed that the Gene Ontology (GO) categories did not change in the three cell lines, but changes in gene expression levels were evident for many genes. After ¹²⁵I particle irradiate NCI-N87 cells, 895 genes were up-regulated, 786 genes were down-regulated; AGS was irradiated by ¹²⁵I seed, there were 124 genes upregulated, 161 genes were down-regulated; BGC-823 cells were treated by ¹²⁵I seed irradiation, 2 412 genes upregulated, 3 243 downregulated genes. After ionizing radiation can cause very complex transcriptional regulation changes, KEGG pathway analysis shows that these differentially expressed genes overlap in a particular cell pathway. Four genes, TRAF3IP2-AS1, SDC1, RABL2B and NOM, were found having at least 2-fold difference in expression (P < 0.05) , and the gene expression alteration was confirmed by qRT-PCR.

CONCLUSIONS¹²⁵I particle irradiation caused gene expression changes in gastric cancer cells. The expressions of TRAF3IP2-AS1, SDC1, RABL2B and NOM are altered significantly in all three cell lines studied, indicating that these genes may play an important role in the ¹²⁵I seed treatment of gastric cancer. These genes could be potential targets for developing anti-cancer drugs in the future.

Cell Line, Tumor ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; radiation effects ; Humans ; Iodine Radioisotopes ; adverse effects ; Stomach Neoplasms ; metabolism ; pathology

Reduced radiosensitivity of lung cancer cells represents a pivotal obstacle in clinical oncology. The hypoxia-inducible factor (HIF)-1α plays a crucial role in radiosensitivity, but the detailed mechanisms remain elusive. A relationship has been suggested to exist between hypoxia and autophagy recently. In the current study, we studied the effect of hypoxia-induced autophagy on radioresistance in lung cancer cell lines. A549 and H1299 cells were cultured under normoxia or hypoxia, followed by irradiation at dosage ranging from 0 to 8 Gy. Clonogenic assay was performed to calculate surviving fraction. EGFP-LC3 plasmid was stably transfected into cells to monitor autophagic processes. Western blotting was used to evaluate the protein expression levels of HIF-1α, c-Jun, phosphorylated c-Jun, Beclin 1, LC3 and p62. The mRNA levels of Beclin 1 were detected by qRT-PCR. We found that under hypoxia, both A549 and H1299 cells were radio-resistant compared with normoxia. Hypoxia-induced elevated HIF-1α protein expression preferentially triggered autophagy, accompanied by LC3 induction, EGFP-LC3 puncta and p62 degradation. In the meantime, HIF-1α increased downstream c-Jun phosphorylation, which in turn upregulated Beclin 1 mRNA and protein expression. The upregulation of Beclin 1 expression, instead of HIF-1α, could be blocked by SP600125 (a specific inhibitor of c-Jun NH2-terminal kinase), followed by suppression of autophagy. Under hypoxia, combined treatment of irradiation and chloroquine (a potent autophagy inhibitor) significantly decreased the survival potential of lung cancer cells in vitro and in vivo. In conclusion, hypoxia-induced autophagy through evaluating Beclin1 expression may be considered as a target to reverse the radioresistance in cancer cells.
Animals ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Autophagy ; Beclin-1 ; Cell Hypoxia ; Cell Line, Tumor ; Cell Survival ; genetics ; radiation effects ; Gene Expression Regulation, Neoplastic ; radiation effects ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Immunoblotting ; Lung Neoplasms ; genetics ; metabolism ; pathology ; Membrane Proteins ; genetics ; metabolism ; Mice, Nude ; Microscopy, Fluorescence ; Microtubule-Associated Proteins ; genetics ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-jun ; metabolism ; Radiation Tolerance ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transplantation, Heterologous ; Tumor Burden ; genetics

BACKGROUNDOsteopontin (OPN) is a secreted phosphoglycoprotein (SSP) that is overexpressed in a variety of tumors and was regarded as a molecular marker of tumors. In this study, we intended to demonstrate the role of OPN in human breast cancer cell line MDA-MB-231.

METHODSRecombinant plasmid expressing small interfering RNA (siRNA) specific to OPN mRNA was transfected into MDA-MB-231 cells to generate the stable transfected cell line MDA-MB-343, and the empty plasmid tansfected cells (MDA-MB-neg) or wildtype MDA-MB-231 cells were used as control cells respectively. Expression of OPN, hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) proteins was analyzed by Western blotting analysis. The radiosensitivity of cells was determined by detecting cell apoptosis, cell proliferation and cell senescence.

RESULTSHIF-1 and VEGF proteins in MDA-MB-343 cells were significantly downregulated upon the efficient knockdown of OPN expression under either hypoxia or normoxia environment. Moreover, expression of OPN protein was upregualted upon hypoxic culture. Stable OPN-silencing also decreased cell invasion, increased cell apoptosis and cell senescence, as well as reduced clonogenic survival, resulting in increase radiation tolerance.

CONCLUSIONSSuppression of OPN gene expression can enhance radiosensitivity and affect cell apoptosis in breast cancer cells. OPN seems to be an attractive target for the improvement of radiotherapy.

Breast Neoplasms ; genetics ; metabolism ; Cell Line, Tumor ; Female ; Gene Expression Regulation, Neoplastic ; drug effects ; genetics ; Humans ; Hypoxia-Inducible Factor 1 ; genetics ; metabolism ; Osteopontin ; genetics ; metabolism ; RNA, Small Interfering ; Radiation Tolerance ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

OBJECTIVETo examine UVB-induced responses in normal human keratinocytes (HaCaT) and epidermoid carcinoma cells (A431) at the cellular and molecular level, and investigated the protective effect of salidroside.

METHODSCells irradiated by UVB at various dosage and their viability was assessed by MTT assays, cell cycle was analysed by flow cytometry. The expression of NF-κB, BCL-2, and CDK6 after 50 J/m(2) UVB irradiation were detected by RT-PCR and western blotting.

RESULTSOur results confirmed greater tolerance of A341 cells to UVB-induced damage such as cell viability and cell cycle arrest, which was accompanied by differential expression changes in NF-κB, BCL-2, and CDK6. UVB exposure resulted in HaCaT cells undergoing G(1)-S phase arrest. When treated with salidroside, HaCaT survival was significantly enhanced following exposure to UVB, suggesting great therapeutic potential for this compound.

CONCLUSIONTaken together, our study suggests that A431 respond differently to UVB than normal HaCaT cells, and supports a role for NF-κB, CDK6, and BCL-2 in UVB-induced cell G(1)-S phase arrest. Furthermore, salidroside can effectively protect HaCaT from UVB irradiation.

Antioxidants ; pharmacology ; Apoptosis ; radiation effects ; Carcinoma, Squamous Cell ; Cell Cycle Checkpoints ; Cell Line, Tumor ; Cell Survival ; drug effects ; radiation effects ; Gene Expression Regulation, Neoplastic ; Glucosides ; pharmacology ; Humans ; Keratinocytes ; radiation effects ; Phenols ; pharmacology ; Ultraviolet Rays

Radiation is the most useful treatment modality for cancer patients. It initiates a series of signal cascades such as DNA damage response (DDR) signaling for repairing damaged DNA, arresting the cell cycle, and inducing cell death. Until now, few genes have been found to be regulated by radiation, which explains the molecular mechanisms of cellular responses to radiation. Although the transcriptional changes caused by radiation have been widely investigated, little is known about the direct evidence for the transcriptional control of DDR-related genes. Here, we examined the radiosensitivity of two non-small cell lung cancer cell lines (H460 and H1299), which have different p53 status. We monitored the time-dependent changes of 24 DDR-related gene expressions via microarray analysis. Based on the basal expression levels and temporal patterns, we further classified 24 DDR-related genes into four subgroups. Then, we also addressed the protein levels of several DDR-related genes such as TopBP1, Chk1 and Chk2, confirming the results of microarray analysis. Together, these results indicate that the expression patterns of DDR-related genes are associated with radiosensitivity and with the p53 statuses of H460 and H1299, which adds to the understanding of the complex biological responses to radiation.
Adaptor Proteins, Signal Transducing/genetics ; Cell Cycle Proteins/genetics ; Cell Line, Tumor ; Cell Survival/radiation effects ; DNA Damage/*radiation effects ; DNA Repair Enzymes/genetics ; DNA-Binding Proteins/genetics ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic/*radiation effects ; Humans ; Lung Neoplasms ; Radiation Tolerance/genetics ; Signal Transduction

The activation of nuclear factor-kappa B1 (NFkappaB1) in cancer cells may confer resistance to ionizing radiation (IR). To enhance the therapeutic efficiency of IR in lung cancer, we screened for microRNAs (miRNAs) that suppress NFkappaB1 and observed their effects on radiosensitivity in a human lung cancer cell line. From time series data of miRNA expression in gamma-irradiated H1299 human lung cancer cells, we found that the expression of miR-9 was inversely correlated with that of NFkappaB1. Overexpression of miR-9 down-regulated the level of NFkappaB1 in H1299 cells, and the surviving fraction of gamma-irradiated cells was decreased. Interestingly, let-7g also suppressed the expression of NFkappaB1, although there was no canonical target site for let-7g in the NFkappaB1 3' untranslated region. From these results, we conclude that the expression of miR-9 and let-7g could enhance the efficiency of radiotherapy for lung cancer treatment through the inhibition of NFkappaB1.
Base Sequence ; Cell Line, Tumor ; Cell Survival/genetics/radiation effects ; Gene Expression Profiling ; *Gene Expression Regulation, Neoplastic/radiation effects ; Humans ; Lung Neoplasms/genetics/metabolism ; MicroRNAs/genetics/*metabolism ; NF-kappa B p50 Subunit/genetics/*metabolism ; Radiation Tolerance/*genetics ; Radiation, Ionizing ; Sequence Alignment

BACKGROUND AND OBJECTIVERadioresistant cells in esophageal cancer is one of the important reasons for the local failure of radiotherapy. In recent years, some researchers used gene chip technology to screen the differentially expressed genes between parental and radioresistant human esophageal cancer cells. But there were some problems in these studies, for example comparing cells at only one time interval, and genetic background not matching. In this study, we selected 3 different pairs of parental and radioresistant human esophageal cancer cells, and compared the gene expression profiles by cDNA microarray at 3 time intervals to identify and analyze the differentially expressed genes between parental and radioresistant human esophageal cancer cells.

METHODSWe compared the gene expression profiles between parental cells (TE13, Seg-1, Kyse170) and radioresistant cells (TE13R, Seg-1R, Kyse170R) before, and at 8 h and 24 h after irradiation with a cDNA microarray consisting of 48 000 genes (Human Genome). We identified differentially expressed genes by Pathway and GO analyses, and verified the differentially expressed genes LEF1 and CTNNB1 by RT-PCR.

RESULTSA total of 460, 451, and 397 differentially expressed genes were found before, and at 8 h and 24 h after irradiation. After Pathway and GO analyses, 14 differentially expressed genes, participating in cell growth, apoptosis, cell cycle regulation, gene repair and signal transmission, were selected to further research. LEF1 and CTNNB1 were verified by RT-PCR, and the results were consistent with those of cDNA microarray.

CONCLUSIONSThe WNT signal pathway may be an important pathway participating in the formation of radioresistance of esophageal cancer cells. LEF1 and CTNNB1 may be the important genes causing the esophageal cancer cell radioresistance.

Carcinoma, Squamous Cell ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; radiation effects ; Esophageal Neoplasms ; genetics ; metabolism ; pathology ; Gene Expression Regulation, Neoplastic ; Humans ; Lymphoid Enhancer-Binding Factor 1 ; metabolism ; Oligonucleotide Array Sequence Analysis ; Radiation Tolerance ; Transcriptome ; Wnt Signaling Pathway ; radiation effects ; beta Catenin ; metabolism

BACKGROUND AND OBJECTIVEVarious factors affect the radioresistance of tumor cells, with unknown molecular mechanism(s). Many genes have been found to associate with the radioresistance of tumor cells, however, the precise mechanism of these genes have not been elucidated. This paper was to analyze the differential expressions of DNA repair genes in esophageal carcinoma cells at different time after X-ray irradiation, and to investigate the role of these DNA repair genes in radiation resistance.

METHODSEsophageal cancer parental cells Seg-1 were treated with continuous 2 Gy of fractionated irradiation until the total dose reached 60 Gy to establish the radioresistant cell line Seg-1R. Total RNA was extracted from each cell line at 0, 8, and 24 h after irradiation. Illumine Human-6 V3 microarray was used to identify differentially expressed genes between parental and radioresistant cells. Ten genes involved in DNA repair were obtained and their expressions at different time points after irradiation were analyzed by Gene Ontology analysis.

RESULTSTen DNA repair associated genes were found to be differentially expressed. Three of these genes, SLK, HMGB1, and PMS1, were not only differentially expressed between parental and radioresistant cell lines, but also expressed differently at different time points after irradiation in the same cell line.

CONCLUSIONSPMS1 may be an important factor involved in the mechanism of radioresistance of esophageal carcinoma cells.

Cell Line, Tumor ; radiation effects ; DNA Repair ; genetics ; DNA, Neoplasm ; genetics ; Esophageal Neoplasms ; genetics ; pathology ; Gene Expression Regulation, Neoplastic ; radiation effects ; Humans ; MutL Proteins ; Neoplasm Proteins ; genetics ; metabolism ; Oligonucleotide Array Sequence Analysis ; Radiation Tolerance ; Transcriptome ; X-Rays

OBJECTIVETo investigate the effects of radiosensitivity and X-ray dose on the expression of miR-7 in nasopharyngeal carcinoma (NPC) cells.

METHODSLow radiosensitive NPC cells CNE-1 and high radiosensitive NPC cells CNE-2 were exposed to 0, 2 and 8 Gy X-ray. The total RNAs of the cell lines were extracted 10 h after radiation for reverse transcription of miR-7 and 18S rRNA by stem-loop primer and random hexamers, respectively. The non-irradiated CNE-1 cells served as the control sample and the relative quantity of the expression level was calculated after real-time PCR using SyBR green.

RESULTSmiR-7 expression differed significantly between CNE-1 and CNE-2 cells (4.49-/+3.62 vs 1.29-/+1.10, F=135.483, P<0.001). The radiation dose also significantly affected the expression of miR-7 in NPC cells (F=39.565, P<0.001). CNE-1 cells with a 2 Gy exposure had the highest expression level of miR-7, while the non-irradiated CNE-1 cells had the lowest expression. CNE-2 cells exposed to 2 Gy X-ray had the lowest expression level of miR-7 and the non-irradiated CNE-2 cells had the highest.

CONCLUSIONRadiosensitivity and radiation dose of X-ray have significant effect on the expression of miR-7 in NPC cells, indicating that miR-7 plays an important role in radioresistance of NPC cells to X-ray, and suppressed miR-7 expression may elevate the radiosensitivity of NPC cells.

Apoptosis ; radiation effects ; Carcinoma ; Cell Line, Tumor ; Dose-Response Relationship, Radiation ; Gene Expression Regulation, Neoplastic ; radiation effects ; Humans ; MicroRNAs ; genetics ; Nasopharyngeal Neoplasms ; genetics ; Radiation Tolerance ; genetics ; X-Rays