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Objective:To investigate the effect of decreasing DKC1 gene expression on radiosensitivity of HeLa cells.Methods:A cell model with low expression of DKC1 gene was established by shRNA technology with lentivirus as vector, and the interference efficiency was verified by RT-PCR and Western blot assay. Cells were divided into two groups of interference (Lv-shDKC1) and its negative control. Telomerase activity was detected by TRAP-ELISA, and telomere length was measured by Real-time PCR. Cell survival was obtained through clone formation assay and fitted by multi-target single-hit model, and radiobiological parameters ( D0, Dq, N, SF2) and radiosensitization ratio (SER) were calculated. Results:After DKC1 interfering, the expression levels of mRNA and protein of DKC1 in HeLa cells were significantly decreased by (71.330±4.112)% ( t=25.53, P<0.05) and (35.520±3.804)% ( t=4.833, P<0.05), respectively. Compared with the blank control group and negative control group, the telomerase activity of Lv-shDKC1 group decreased significantly from 0.900±0.044 and 0.897±0.031 to 0.713±0.021 ( F=31.44, P<0.05), the relative telomere length was significantly decreased from 4.233±0.306 and 4.633±0.379 to 2.667±0.404 ( F=39.15, P<0.05). The telomerase activity and relative telomere length of blank control group and Lv-shDKC1 negative control group had no significant difference( P>0.05). SF2 in the interference group (0.571±0.006) was significantly lower than that of the blank control group (0.861±0.009) and the Lv-shDKC1 negative control group (0.807±0.002) ( F=1812, P<0.05), and the radiosensitization ratio (SER) of shDKC1 interference was 1.508. Conclusions:Downregulation of DKC1 in human cervical cancer HeLa cells enhances the radiosensitivity through inhibiting the activity of telomerase and shortening the length of telomere. DKC1 gene may become a new target of radiosensitization.
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Objective@#To investigate the relationship between the expression of mucin 1 and collagen Ⅳ and the clinical characteristics in invasive breast cancer by using the quantum dots immunofluorescence imaging technique.@*Methods@#The expressions of mucin 1 and collagen Ⅳ were detected simultaneously by quantum dots immunofluorescence imaging technique in 94 cases of breast cancer from July 2007 to July 2010 in Affiliated Hospital of Guilin Medical University. The correlation of mucin 1 and collagen Ⅳ quantitative parameters with clinicopathological features and the prognosis were also analyzed.@*Results@#The positive rates of mucin 1 in human breast cancer tissues marked by quantum dots immunofluorescence imaging technique and immunohistochemistry were 73.4 % (69/94) and 69.1 % (65/94), the positive rates of collagen Ⅳ were 53.2 % (50/94) and 47.9 % (45/94), and the differences were not statistically significant (both P > 0.05) Quantum dots immunofluorescence imaging technique was consistent with conventional immunohistochemistry (IHC) in detecting the expressions of mucin 1 and collagen Ⅳ in human breast cancer tissues (κ = 0.763, P = 0.000; κ=0.759, P = 0.000). The expression of mucin 1 was negatively correlated with collagen Ⅳ (r = -0.883, P < 0.01). The expressions of mucin 1 and collagen Ⅳ were respectively associated with tumor size (F = 3.683, P = 0.029; F = 4.922, P = 0.009), histological grading (F = 3.529, P = 0.033; F = 3.912, P = 0.023), lymph node metastasis (t = -4.868, P = 0.000; t = 3.868, P = 0.000), pathological stage (t = -8.337, P = 0.000; t = 5.962, P = 0.000) and 5-year disease free survival rate (both P = 0.000), and the differences were statistically significant (all P < 0.05).@*Conclusion@#The co-detection of mucin 1 and collagen Ⅳ by using quantum dots immunofluorescence imaging technique provides direct evidence determining the biologic behaviors of breast cancer and evaluating the prognosis.
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DNA microarray has become an essential medical genetic diagnostic tool for its high-throughput, miniaturization and automation. The design and selection of oligonucleotide probes are critical for preparing gene chips with high quality. Several sets of probe design software have been developed and are available to perform this work now. Every set of the software aims to different target sequences and shows different advantages and limitations. In this article, the research and development of these sets of software are reviewed in line with three main criteria, including specificity, sensitivity and melting temperature (Tm). In addition, based on the experimental results from literatures, these sets of software are classified according to their applications. This review will be helpful for users to choose an appropriate probe-design software. It will also reduce the costs of microarrays, improve the application efficiency of microarrays, and promote both the research and development (R&D) and commercialization of high-performance probe design software.
Subject(s)
Base Sequence , Oligonucleotide Array Sequence Analysis , Oligonucleotide Probes , Sensitivity and Specificity , Software , Software DesignABSTRACT
Objective To investigate the relationship between RKIP expression and the efficiency of radiotherapy in NPC patients and evaluate the possibility of using RKIP as a predictor of radiosensitivity.Methods A total of 180 patients with NPC in Sun Yat-sen University Cancer Center without evidence of distant metastasis at initial diagnosis were enrolled in this study,who had received intensity-modulated radiotherapy alone.Patients were classified into 2 groups according to criteria below:patients with biopsy proven recurrent diseases occurring at nasopharynx and/or neck within 5 years after radiotherapy were classified as the radioresistant group.The pathological type at relapse was the same as the previous one before treatment.Patients with a minimum follow-up of 5 years after radiotherapy without evidence of recurrence at the original site of the tumor were classified as the radiosensitive group.Patients in the 2 groups were matched according to the factors related with radiosensitivity.RKIP was examined by immunohistochemical staining before radiotherapy.The relationship between RKIP expression and the effect of radiotherapy were analyzed.Results The positive rate of the RKIP expression in the radiosensitive group versus the radioresistant group was 80.0％ versus 26.7％.The positive rate (x2 =12.498,P ＜0.01) and the intensity of the RKIP expression (x2 =51.429,P ＜ 0.01) were significantly different between 2 groups with a negative correlation with radio-resistance to NPC (r =-0.344,-0.535,respectively,P ＜ 0.01).Based on the RKIP expression,the radiosensitivity,specificity,accuracy,positive predictive value,negative predictive value,false positive and false negative were predicted as follows:80.0％,73.3％,77.2％,75.0％,78.6％,26.7％,and 20.0％,respectively.Conclusions RKIP protein shows negative correlation with radioresistance to NPC and could serve as a biomarker in preliminarily screening the intrinsic radiosensitivity of NPC.
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Purpose: To realize the detection of T-wave end with an efficient and accurate method. Methods: R-wave was lo-cated using wavelet transforming, and then the T-wave detection interval was identified accttrately by avoiding the influence of heart rate and P-wave. In addition, T-wave peaks were determined referring to the modulus maxima in the interval. Based on these, the T-wave end was located with a simple and practical geometrical method, which was applied for the evaluation of QT database. Results: The positioning capability of the above-mentioned method reached to (-0.35225±18.5869) ms which was comparable or even better than those manual annotations from QT database by cardiologists. Conclusions: The experimental results showed that our algorithm for T-wave end detection is robust to noise, baseline drift and waveform morphological varia-tions, and easy to calculate and to realize.