Methods for screening tumors for p53 status and therapeutic exploitation

Development of a 21-miRNA Signature Associated With the Prognosis of Patients With Bladder Cancer

Objective: To develop a prognostic signature for patients with bladder cancer (BC).

Methods: We identified differentially expressed miRNAs between normal bladder tissue and bladder cancer in the TCGA-BCLA dataset and evaluated prognostic values of these miRNAs. Then, a 21-miRNA signature was constructed based on the results of Cox proportional hazards regression model. Furthermore, functional enrichment analyses were conducted to explore the potential effects of the target genes of these 21 miRNAs.

Results: Seventy six differentially expressed miRNAs were identified, among which 21 miRNAs including hsa-let-7c, mir-143, mir-944, mir-192, mir-590, mir-490, mir-141, mir-93, mir-1-2, mir-200c, mir-133a-1, mir-1-1, mir-133b, mir-20a, mir-185, mir-19a, mir-19b-2, mir-19b-1, mir-17, mir-15a, and mir-133a-2 were demonstrated to be significantly correlated with the overall survival (OS) of bladder cancer patients using Kaplan-Meier survival analysis and Log-rank test. The results of Chi-square test and multivariable logistic regression analysis showed that the 21-miRNA signature was significantly associated with the diagnosis type and T stage of bladder cancer. Univariate and multivariable survival analyses indicated that the 21-miRNA signature was an independent factor in predicting the overall survival of patients with bladder cancer. The results of functional enrichment analysis suggested that the target genes of these 21 miRNAs were mostly enriched in critical cancer-related biological processes and pathways, and the PPI network suggested that 60 targeted genes interacted with a minimum of 30 genes were at the hub of the whole network. In addition, we performed a multivariate nomogram and decision curve analysis (DCA) to evaluate the clinical application of 21-microRNA signature.

Conclusion: We introduced a 21-miRNA signature which was associated the prognosis of patients of bladder cancer, and inspirational ideas for the future basic and clinical exploration.

Gene expression profiling in digestive tract tumors: From basic research to clinical practice

Gene expression profiling is a new method that can be used to study the whole genome function. It is also a comprehensive research technique combining life science with information science. Gene expression profiles have not only been thoroughly and fundamentally studied in digestive tract tumors with regard to gene function, pathogenesis, gene network regulation, and biological characteristics, but also been applied to clinical diagnosis, differential diagnosis, molecular typing, targeted therapy, and other aspects. However, it is still necessary to fully mine and utilize the huge amount of data generated continuously in this process, effectively standardize the construction and management of the existing gene expression database, gradually realize data sharing, and strengthen the quality control of gene expression profiling technology in order to make the gene expression profiling technology become more stable and rapid in the future research.

Chk2 deficiency alleviates irradiation-induced taste dysfunction by inhibiting p53-dependent apoptosis

OBJECTIVE

Taste dysfunction is one of the most common complications following radiotherapy, which leads to decreased appetite and life quality of patients suffering from head and neck cancer. The aim of this study was to investigate the role of checkpoint kinase 2 (Chk2) deficiency in irradiation-induced taste dysfunction.

MATERIALS AND METHODS

Alterations in oxidative stress, DNA damage, and potential signaling pathway were compared between Chk2-deficient (Chk2^-/- ) mice and their wild-type (WT) littermates pre-irradiation and 7 and 30 days postirradiation by biochemistry and immunohistochemistry.

RESULTS

Chk2^-/- mice showed less loss of type II and type III taste cells, lower expression of p53, caspase-3, and cleaved caspase-3, and lower apoptosis levels. However, no significant differences in H₂ O₂ and MDA concentrations, T-SOD and GSH-Px activities, and expression of SOD1, SOD2, and 8-OHdG were detected in the taste buds of Chk2^-/- mice as compared to those of WT mice.

CONCLUSION

Chk2 deficiency downregulated the expression of p53 and inhibited cellular apoptosis, partly contributing to the radioprotective effect on taste cells, but did not alter oxidative stress levels, antioxidant ability, and oxidative DNA damage in taste buds.

Progress in research of microRNA-24

MicroRNAs are endogenous, small, and noncoding RNAs of 18-24 nucleotides in length that regulate tissue/organ development, cell growth, differentiation, and apoptosis and play an essential role in the development and progression of tumors. This paper will discuss the biological characteristics of microRNA-24 and its biological role in tumors and non-tumor diseases, with an aim to provide new clues to disease diagnosis and treatment to reduce the mortality of patients.

Roles of autophagy-related genes Beclin-1 and LC3 in the development and progression of prostate cancer and benign prostatic hyperplasia

Prostate cancer (PCa) is common in Western populations and the second leading cause of cancer-related mortality among males in North America, with an increasing morbidity in China and other Asian countries. The aim of this study was to evaluate the protein expression of autophagy-related genes Beclin-1 and LC3 in patients with prostate cancer (PCa) and benign prostatic hyperplasia (BPH) and elucidate their association with p53 and Bcl-2. The total protein of 34 PCa and 50 BPH samples was extracted and the expression of Beclin-1 and LC3 was analyzed by western blotting assay. Subsequently, a total of 96 paraffin-embedded BPH tissue samples was subdivided into 2 groups, one group in which patients had received 5α-reductase inhibitor, due to its effect of androgen ablation, and the control group, in which patients had not received the 5α-reductase inhibitor. The samples were randomly collected and examined using immunohistochemical (IHC) analysis. The western blot analysis demonstrated that Beclin-l and LC3 expression was higher in BPH tissues compared to PCa tissues (P<0.001). There was no statistically significant difference between PCas of different Gleason scores (P>0.05). The result of IHC revealed that Beclin-l and LC3 expression in the group of patients who had received the 5α-reductase inhibitor was significantly higher compared to that in the control group; however, the expression of Bcl-2 and p53 was lower (P<0.05). Beclin-1 expression exhibited a negative correlation with Bcl-2 (r=-0.402, P<0.001), whereas LC3 expression exhibited a positive correlation with Beclin-1 (r=0.345, P=0.001) and a negative correlation with Bcl-2 (r=-0.216, P=0.035). It was suggested that autophagy-related genes Beclin-l and LC3 may be involved in the development and progression of PCa. In addition, the expression of these genes was higher in patients with BPH who had received a 5α-reductase inhibitor, due to androgen reduction. As a result, the induced autophagy may reduce the risk of PCa.

Clinical analysis by microchip capillary electrophoresis

Clinical analysis often requires rapid, automated, and high-throughput analytical systems. Microchip capillary electrophoresis (CE) has the potential to achieve very rapid analysis (typically seconds), easy integration of multiple analytical steps, and parallel operation. Although it is currently still in an early stage of development, there are already many reports in the literature describing the applications of microchip CE in clinical analysis. At the same time, more fully automated and higher throughput commercial instruments for microchip CE are becoming available and are expected to further enhance the development of applications of microchip CE in routine clinical testing. To put into perspective its potential, we briefly compare microchip CE with conventional CE and review developments in this technique that may be useful in diagnosis of major diseases.

Reversal of 5-flouroucial resistance by adenovirus-mediated transfer of wild-type p53 gene in multidrug-resiatant human colon carcinoma LoVo/5-FU cells

AIM: To observe the reversal effects of wide-type p53 gene on multi-drug resistance to 5-FU (LOVO/5-FU).

METHODS: After treatment with Ad-p53, LOVO/5-FU sensitivity to 5-Fu was investigated using tetrazolium dye assay. Multidrug resistance gene-1 (MDR1) gene expression was assayed by semi-quantitative reverse transcription-polymerase chain reaction and the expression of p53 protein was examined by Western blotting.

RESULTS: The reversal activity after treatment with wide-type p53 gene was increased up to 4.982 fold at 48 h. The expression of MDR1 gene decreased significantly after treatment with wide-type p53 gene, and the expression of p53 protein lasted for about 5 d, with a peak at 48 h, and began to decrease at 72 h.

CONCLUSION: Wide-type p53 gene has a remarkable reversal activity for the high expression of MDR1 gene in colorectal cancers. The reversal effects seem to be in a time dependent manner. It might have good prospects in clinical application.