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Objective:To investigate the effect of methyltransferase like 14 (METTL14) on the proliferation and invasion of breast cancer (BC) cells by regulating cyclin L2 (Cyclin L2, CCNL2) through m6A modification.Methods:Cancer tissues and paracancerous tissues of BC patients in Yantaishan hospital were collected from Aug. 2018 to Feb. 2020. The expression levels of m6A, METTL14 and CCNL2 in tissues were detected by high performance liquid chromatography/mass spectrometry (HPLC/MS) and qRT-PCR. Dual-luciferase reporter assay, qRT-PCR, and western blot were used to verify the regulatory relationship between METTL14 and CCNL2. RIP experiments verified the regulatory relationship between YTH domain-containing family protein (YTHDF2) and CCNL2. Cell viability was detected by MTT method, and cell invasion ability was detected by Transwell.Results:Compared with normal cells (0.24±0.02) and tissues (0.18±0.02) , BC cells MCF-10A (0.47±0.03, t=11.05, P<0.001) and HS-578T (0.41±0.03, t=8.17, P=0.001) and BC tissues (0.39±0.02, t=12.86, P<0.001) m6A level increased. Compared with normal tissues (1.00±0.26) (0.84±0.07) , METTL14 mRNA (1.57±0.28, t=13.50, P<0.001) and protein levels (1.66±0.11, t=10.89, P<0.001) in BC tissues were significantly increased high. Compared with the control group (100.00±10.11) (1.00±0.12) , the BC cell invasion ability (54.15±6.21, t=6.69, P=0.003) and activity (0.64±0.06, t=4.65, P=0.010) were weakened. Compared with the control group (100±11.05) (1±0.13) , the BC cell invasion ability (175.31±13.45, t=7.49, P=0.002) and activity (2.16±0.16, t=9.75, P=0.002) in the METTL14 overexpression group were enhanced, and the effects of METTL14 on cell invasion (137.41±12.64, t=3.56, P=0.024) and activity (1.64±0.15, t=5.59, P=0.005) were partially reversed after m6A inhibitor treatment change. Compared with normal tissues, CCNL2 expression was down-regulated in BC tissues, and the interaction between CCNL2 and METTL14 was confirmed. Compared with the control group (1.00±0.1) (0.64±0.05) , knockdown of METTL14 could make CCNL2 mRNA (1.67±0.05) . 0.13, t=7.08, P=0.002) and protein (1.09±0.09, t=7.57, P=0.002) were up-regulated. METTL14 knockout enhanced the stability of CCNL2 mRNA through a YTHDF2-dependent pathway, compared with sh-METTL14 group (50.47±5.16) (0.52±0.05) , BC cell invasion ability of sh-METTL14+sh-CCNL2 group (71.69±6.41, t=4.47, P=0.011) and activity (0.64±0.05, t=2.94, P=0.042) were improved. Conclusion:METTL14 inhibits the expression of CCNL2 through m6A modification to enhance the invasion and activity of BC cells.
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Objective:To investigate the effects of circ_000543 derived from hypoxic exosomes on proliferation and invasion of breast cancer (BC) cells.Methods:Bioinformatic website was used to predict the abnormal expression of circ_000543 in BC tissue and the transcription factor that might regulate circ_000543. Double luciferase report experiment and ChIP assay were used to confirm the regulation relationship between YY1 and circ_000543. Exosomes were separated from normal BC cells and BC cells under hypoxic condition, and qRT-PCR was adopted to detect the expression of circ_000543 in exosomes. The expression of circ_000543 and YY1 in exosomes was intervened and the exosomes were cocultured with BC cells under normoxia. CCK8 and Transwell assay was used to detect the proliferation and invasive ability individually.Results:qRT-PCR experiment found that, compared with MCF-10A cells (1±0.11) and exosomes isolated from normoxic cells (1±0.10), circ_000543 expression was up-regulated in BC cells (1.59±0.13) and exosomes derived from cells under hypoxic condition (1.63±0.12) ( t=6.001, P=0.004; t=6.986, P=0.002). Exosomes derived from cells under hypoxic condition promoted proliferation and invasion of BC cells under normoxia. Inhibition of circ_000543 partially offset the effects of exosomes. YY1 induced the expression of circ_000543 in BC cells as a transcription factor. The expression of circ_000543 was inhibited when YY1 expression was down-regulated; at the same time, down-regulation of YY1 inhibited the effects of exosomes on proliferation and invasion of BC cells. Conclusion:The transcription factor YY1 promoted proliferation and invasion of BC cells by inducing hypoxic breast cancer-derived exosomal circ_000543.
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Objective: To explore the value of 4D-CTA based on computed tomography dynamic angiography for preoperative evaluation of meningioma. Methods: Totally 34 patients with intracranial meningioma underwent cranial dynamic volume CT scan. Then 3D-CTA and 4D-CTA related post-processing were performed. The difference of tumor size, tumor feeding artery and the relationship of tumor and skull, passing artery and peripheral venous system showed with 3D-CTA and 4D-CTA were compared. Results: There was no significant difference between 3D-CTA and 4D-CTA in evaluating tumor size and tumor feeding artery (both P> 0.05). The percentage of definite draining veins evaluated with 3D-CTA was 70.59% (24/34), lower than that with 4D-CTA (94.12% [32/34], P 0.05). Conclusion: CT dynamic angiography can accurately evaluate the size of meningioma, the feeding artery and relationship with surrounding tissue, therefore providing comprehensive preoperative information of meningioma.
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Objective@#To compare and quantify the differences in size-specific dose estimates (SSDE) obtained by effective diameter and water-equivalent diameter from the central slice of the scan range in head CT examination.@*Methods@#A total of 111 consecutive adult patients who underwent head CT examination were enrolled in this study. All of CTDIvol values in the dose report were documented. The dataset was assigned into group A and group B, based on the individual size-dependent conversion factors (f) of effective diameter (deff) and water-equivalent diameter (dw) at the central slice multiplied by normalized volume computed tomography dose index (CTDIvol ) respectively. Body size, f and SSDE were calculated. With SSDEgross served as the reference level, the performance of SSDEdeff and SSDEdw was evaluated.@*Results@#Statistically significant differences were found in body size (t=47.587, P<0.05) and f(z=-9.242, P<0.05) between group A and group B. Statistically significant difference also existed in SSDE (t=-46.687, P<0.05), (56.20±2.66) and (53.49±2.48) mGy for group A and group B respectively. Strongly positive correlation was shown in body size (r=0.873, R2 =0.761) and SSDE (r=0.974, R2 =0.949) between group A and group B(all P<0.05). Positive correlation was also found between SSDEdeff and SSDEgross(r=0.900, R2 =0.809), SSDEdw and SSDEgross (r=0.904, R2 =0.817, all P<0.05). Mean absolute difference was 2.34 and 0.78 mGy, for SSDEdeff vs. SSDEgross and SSDEdw vs. SSDEgross respectively; mean absolute relative difference was 4.38%, 1.40%; root mean square difference was 1.17 mGy (2.17%), 1.06 mGy (1.91%). Interquartile range and full range of SSDEdeff and SSDEdw were 3.22 vs. 2.39 mGy, 13.65 vs. 12.48mGy, respectively. A less degree of variation was observed in SSDEdw than that in SSDEdeff.@*Conclusions@#SSDEdw values based on the water-equivalent diameter at the central slice of the scan range got better agreement with those derived from all slices, which could serve as a simpler and more valid indicator to represent the average value of size-specific dose estimates of the whole scan range in head CT examination.
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Objective To explore the validity of the size-specific dose estimate (SSDE) derived from the water-equivalent diameter (Dw)value of the slice located in the middle of the scan range in the head CT examination. Methods A total of 197 patients underwent head CT nonenhanced scan were enrolled in this retrospective study. The Dw, size-dependent conversion factor (f), normalized volume CT dose index (CTDIvol) and SSDE values of all slices were calculated. Two sets of SSDE, SSDEgroand SSDEcenbased on the Dwvalues slice by slice (Dw-gro) and the Dwvalues of the slices in the middle of the scan range (Dw-cen), were obtained across all patients. Pearson correlation analysis and linear regression analysis were performed for Dw-grovs Dw-cen, Spearman correlation analysis and linear regression analysis for SSDEgrovs SSDEcen, SSDE vs Dw, CTDIvolvs Dw. With the reference of SSDEgrovalue, mean absolute relative difference (MARD) of SSDEcen values were calculated to assess its accuracy and the correlated factors of MARD was analyzed with multivariate linear stepwise regression analysis. Results The minimal Dwvalue close to the roof of the skull corresponded to the maximal value of f and SSDE, which was the minimal value of CTDIvol. The significant positive correlation was showed between Dw-grovs Dw-cen, SSDEgrovs SSDEcen, SSDE vs Dw, CTDIvolvs Dw(r=0.947, 0.931, 0.416, 0.626;P＜0.05). The values of Dw,groand Dw-cenwere (16.94±0.69) and (18.50±0.62) cm respectively. The values of SSDEgroand SSDEcenwere [54.10 (52.29, 56.39)] mGy and [53.77 (51.85, 55.25)] mGy respectively. An approximation of SSDEcenvalues with an average of 1.62% of the gross MARD was found to match the reference value. Multivariate linear stepwise regression analysis indicated that MARD had negative correlation with Dw(β=–1.319,P＜0.05), positive correlation with CTDIvol(β=0.202,P＜0.05), and f was not included in the multivariate regression equation. Conclusion SSDEcenbased on the Dwvalue of the slice located at the center of the scan range yields small MARD value and can represent a reliable SSDE estimation in the head CT examination.
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<p><b>OBJECTIVE</b>To observe the expression of the C-terminal truncated human apoptosis-inducing factor (AIF) and its biological effect on MCF-7 cells.</p><p><b>METHODS</b>PcDNA3.0-FDT-AIFδ1-480 was transfected into human breast carcinoma MCF-7 cells with lipofectamine. The expression of the truncated AIF gene was detected by Western blotting, and its effects on the biological behaviors of MCF-7 cells and on the expression of cytochrome c (cytC) were evaluated using flow cytometry, MTT assay, colony-forming assay, and mitochondrial membrane potential measurement.</p><p><b>RESULTS</b>PcDNA3.0-FDT-AIFδ1-480 enhanced AIF expression in MCF-7 cells, obviously inhibited the cell proliferation, and significantly reduced the mitochondrial membrane potentials (P<0.05). Transfection of the cells with PcDNA3.0-FDT-AIFδ1-480 promoted the expression of cytC and resulted in significantly increased apoptosis of MCF-7 cells (P<0.05).</p><p><b>CONCLUSION</b>The expression of C-terminal truncated human AIF gene can induce apoptosis of human MCF-7 cells by promoting cytC release from mitochondria.</p>