ABSTRACT
Objective@#To investigate the inhibitory effect of 17AAG-Cypate micelles on the non-small cell lung cancer A549 cells in nude mice and to explore its possible mechanism.@*Methods@#A549 lung adenocarcinoma tumor-bearing nude mice were established. The nude mice were treated with saline ( saline group), X-ray (X-ray group), 17AAG micelles+ X-ray (17AAG-M/X group) and 17AAG-Cypate micelles+ laser/X-ray (17AAG-Cypate-M/L+ X group), respectively. The growth of xenograft tumors in different groups was measured on a regular basis to delineate the growth curve. The expression of proliferating cell nuclear antigen (PCNA) was measured by immunohistochemistry. The microvascular density was detected. The apoptosis of xenograft tissues was observed by TUNEL staining. The expression levels of p-ERK1/2 and p-AKT were quantitatively measured by Western blot.@*Results@#Compared with the saline group, varying degrees of inhibition of tumor growth were observed in the X-ray, 17AAG-M/X-ray and 17AAG-Cypate-M/L+ X groups, particularly in the 17AAG-Cypate-M/L+ X group (all P<0.05). In all groups, the expression levels of PCNA were significantly down-regulated (all P<0.05), the microvascular density was remarkably reduced (all P<0.05) and the expression levels of p-ERK1/2 and p-AKT were considerably down-regulated (all P<0.05).@*Conclusions@#17AAG-Cypate micelles can inhibit the growth of human non-small cell lung cancer in nude mice, probably by reducing the activity of p-ERK1/2 and p-AKT, thereby weakening the activation of the MAPK-ERK and PI3K-AKT signaling pathways.
ABSTRACT
Objective To investigate the influence of down-regulation NEK-2 level on the radiosensitivity of A549 cells.Methods NEK-2 siRNA was transfected to A549 cells with liposome and NEK-2 expression level was inspected by Western blot.The radiosensitivity was detected by clone formation experiment.Cell cycle and cell apoptosis were analyzed by flow cytometry.Immunofluorescence experiment was used to detect the DNA double strand break and repair.Results NEK-2 siRNA successfully suppressed NEK-2 expression in A549 cells and resuced the cell proliferation ability after irradiation compared to the blank control group and the negative control group.It can improve the radiosensitivity of A549 cells (The radiosensitivity of A549 cells enhanced significantly.).The D0 values declined form 1.80 Gy to 1.40 Gy,and the sensitizing enhancement ratio was 1.32.After irradiation,compared to negative control group,the apoptosis rate was significantly improved (7.85％ to 17.17％),cells in G2/M phase were obviously increased (9.23％ to 30.16％),the DNA double strand break rate was increased (100％ to 165％) and the DNA damage repair rate was reduced (100％ to 48％) in NEK-2 siRNA group.The comparisons among the groups wer statistically significant (P＜0.05).Conclusions NEK-2 siRNA reduced the proliferation and increased the radiosensitivity of A549 cell line,probably by affecting the cell cycle,promoting cell apoptosis and suppressing DNA damage repair.
ABSTRACT
Objective To investigate the radiosensitizing effect of 17AAG-cypate micelles on human non-small cell lung cancer A549 cells and its possible mechanism.Methods (1) A single-hit multi-target model formula was used to analyze the radiosensitizing effects of 17AAG-M and 17AAG-cypate-M.(2) The effects of 17AAG-cypate-M on the viability of A549 cells under laser and X-ray irradiation were analyzed by MTT assay.(3) The effect of the drugs on the cell senescence was observed by β-galactosidase staining assay.(4) The effects of different treatment conditions on DNA damage repair were analyzed by γ-H2AX immunofluorescence staining assay.(5) The expression of p-Erk1/2 and p-Akt was measured by Western blot.The paired t test was used for analyzing the differences between groups.Results Compared with the X-ray irradiation group,the X-ray+17AAG-cypate-M group had a lower mean lethal dose and a sensitization enhancement ratio greater than 1,indicating that 17AAG-cypate-M had a radiosensitizing effect.Compared with the 17AAG-M group,the 17AAG-cypate-M group showed significantly lower cell viability (P<0.01),a significantly higher percentage of aging cells (P<0.01),and significantly further delayed DNA damage repair (P<0.01).And the 17AAG-cypate-M group had lower expression of p-Erk1/2 and p-Akt than the 17AAG-M group.Conclusions Compared with 17AAG-M,17AAG-cypate-M has a higher radiosensitizing effect on A549 cells.The mechanism might be inducing the cell senescence,delaying DNA damage repair,and inhibiting the expression of p-Erk1/2 and p-Akt.