Objective To study the effects of microRNAl01 (miR-101)on radiosensitization of human uterine cervix cancer HeLa cells and underlying mechanism.Methods HeLa cells were divided into three groups including blank control,miRNA negative control and miR-101 transfection group.The cells were irradiated by 160 kVp X-ray generated from a linear accelerator at a dose rate of 1.15 Gy/min.Real-time quantitative PCR (qRT-PCR) was used to detect the expression of miR-101.The clonogenic survival assay was applied to evaluate the effect of miR-101 on radiosensitization of HeLa cells.γ-H2AX immunofluorescence and Western blot assays were performed to observe DNA double-strand breaks and the protein expressions of ATM and DNA-PKcs of HeLa cells,respectively.Results Compared with the negative control group,the expression of miR-101 was significantly increased in the HeLa cells at 48 h after transfection with miR-101 mimic,and the survival of HeLa cells over expression of miR-101 was significantly reduced(t =10.75,P ＜ 0.05).The miR-101 had remarkable radiosensitive effect on HeLa cells(F =7.72,P ＜0.05) with a SERD0 of 1.29.Moreover,over-expression of miR-101 could inhibit the repair of DNA damage induced by irradiation.Compared with the control group,the protein expressions of ATM and DNA-PKcs were significantly decreased in the HeLa cells over expression of miR-101.Conclusions Over-expressions of miR-101 could inhibit cell growth and enhance radiosensitivity of HeLa cells by inhibiting the repair of radiation-induced DNA damage.

Objective To study the feasibility of measuring radiation absorbed dose with the fluorescent probe Alexa Fluor 488-DNA-BHQ1.Methods An oligonucleotide dually labeled at its 5'-and 3'-end with fluorescent molecular Alexa Fluor 488 and specific fluorescence inhibitors BHQ1 was prepared.The Alexa Fluor 488-DNA-BHQ1 aqueous solution was exposed with X-ray and its fluorescence intensity was measured.Results When the concentration of Alexa Fluor 488-DNA-BHQ1 was between 0.5 and 1 μmol/L,the fluorescence intensity of its aqueous solution had excellent linear dose response from 0.1 to 30 Gy (R2 =0.99) and it was stably maintained after 40-80 min of irradiation especially at 4℃.Conclusions In the dose range of 0.1-30 Gy,the Alexa Fluor 488-DNA-BHQ1 fluorescent probe can be used to measure radiation absorbed dose.

Objective To study the effects of AuNPs@PEG-AS1411 nanoparticles on radiosensitization of human uterine cervix cancer HeLa cells.Methods AuNPs were synthesized by citrate reduction method and then functioned with PEG and PEG-AS1411, respectively.CCK-8 assay and colon forming assay were used to detect the acute and chronic toxicity effects of AuNPs on HeLa cells, respectively.At the same time, clonogenic survival assay was applied to measure the cell survival rate of HeLa cells after exposure to AuNPs@PEG and AuNPs@PEG-AS1411 combined with X-ray radiation.The intracellular uptake of AuNPs@PEG and AuNPs@PEG-AS1411 in HeLa cells were detected by ICP-MS.Results The CCK-8 assay showed that AuNPs@PEG and AuNPs@PEG-AS1411 were not toxical on HeLa cells(P ＞0.05).But the clonogenic survival assay showed that AuNPs@PEG and AuNPs@PEG-AS1411 had toxicity on HeLa cells significantly after 10 d(t =4.38-11.60, P ＜ 0.05).AuNPs functioned with AS1411 could increase the cellular uptake of AuNPs.AuNPs@PEG and AuNPs@PEG-AS1411 both had significant radiosensitive effect on HeLa cells (F =7.90,48.23, P ＜ 0.05).The values of SERDo for AuNPs@PEG and AuNPs@PEG-AS1411 were 1.12 and 1.20, respectively, when the concentration of Au was 10 mg/L.Conclusions AuNPs@PEG and AuNPs@PEG-AS1411 could cause chronic toxicity on HeLa cells instead of acute effect.PEGylated AuNPs functioned with AS1411 could enhance the radiosensitivity of HeLa cells in vitro.