The putative oncotarget CSN5 controls a transcription-uncorrelated p53-mediated autophagy implicated in cancer cell survival under curcumin treatment.

Curcumin has shown promise as a safe and specific anticancer agent. The COP9 signalosome (CSN) component CSN5, a known specific target for curcumin, can control p53 stability by increasing its degradation through ubiquitin system. But the correlation of CSN5-controlled p53 to anticancer therapeutic effect of curcumin is currently unknown. Here we showed that CSN5-controlled p53 was transcriptional inactive and responsible for autophagy in human normal BJ cells and cancer HepG2 cells under curcumin treatment. Of note, CSN5-initiated cellular autophagy by curcumin treatment was abolished in p53-null HCT116p53-/- cancer cells, which could be rescued by reconstitution with wild-type p53 or transcription inactive p53 mutant p53R273H. Furthermore, CSN5-controlled p53 conferred a pro-survival autophagy in diverse cancer cells response to curcumin. Genetic p53 deletion, as well as autophagy pharmacological inhibition by chloroquine, significantly enhanced the therapeutic effect of curcumin on cancer cells in vitro and in vivo, but not normal cells. This study identifies a novel CSN5-controlled p53 in autophagy of human cells. The p53 expression state is a useful biomarker for predicting the anticancer therapeutic effect of curcumin. Therefore, the pharmacologic autophagy manipulation may benefit the ongoing anticancer clinical trials of curcumin.

microRNA-143 protects cells from DNA damage-induced killing by downregulating FHIT expression.

MicroRNAs (miRNAs) are posttranscriptional modulators of gene expression and play an important role in many developmental processes. Recent studies suggest roles of miRNAs in carcinogenesis. Fragile histidine triad (FHIT) gene deletion, methylation, and reduced Fhit protein expression occur in about 70% of human epithelial tumors and are clearly associated with tumor progression. Although it has been previously reported that Fhit(-/-)cells exhibit more resistance to multi-DNA damage inducers, including ionizing radiation, it remains unclear how miRNAs targeting FHIT in DNA damage response play the role. This study reports that miR-143 directly targets FHIT and that overexpression of miR-143 results in significant G2-phase arrest and protects cells from DNA damage-induced killing. These results indicate an association of FHIT gene inactivation with increased survival after DNA damage and also provide useful information for miRNA-based drug development in two directions: protect cells from DNA damage-induced killing and sensitize cells to radiation therapy.

[Characteristics and Influencing factors of Sperm Interaction with Exogenous DNA].

Exogenous DNA localization and the frequency of spermatozoa carrying exogenous DNA after sperm/DNA co-culture are key to a successful sperm mediated-gene transfer (SMGT). In the study, the characteristics and influencing factors of exogenous DNA uptake by spermatozoa were tested using digoxigenin (DIG) labeled DNA as trace. Results showed that goat spermatozoa could spontaneously take up exogenous DNA. The exogenous DNA was initially bound to the outer sperm membrane at postacrosomal region; subsequently party of the bound DNA was internalized into nucleus. There were considerable differences in the capability of spermatozoa from different donors to bind and internalize exogenous DNA. In 35 samples, binding rates (before DNase I digestion) and internalization rates (the positive rate after DNase I digestion) varied between 4.6%-62.4% and 2.1%-53.8%, respectively. For the spermatozoa from the same goat, the binding and internalization capacities were mostly inhibited by the seminal fluid. Compared to ejaculate sperm, the binding rate and internalization rate were increased three and five times in washed sperm cells, respectively. At the same time, capacitated spermatozoa also had lower exogenous DNA uptake (P<0.01). Dead spermatozoa did not complete the internalization process. The highest positive rate (before DNase I digestion) was found in membrane-broken spermatozoa as a result of freeze-thawing and this was independent of the sperm donors. These results suggest that selection of appropriate sperm donors and optimization of sperm processing procedures are the key steps for successful SMGT.

[The transgenic mice specifically express Cre recombinase in central nerve system].

For specific expressing Cre recombinase in central nerve system (CNS), a transgenic construct (pGFAP-Cre-hGH), containing the beta-globin insulators, 1.8 kb of glial fibrillary acidic protein gene (GFAP) 5' end regulation region, Cre gene and polyA of human growth hormone gene (hGH) was generated, in which the 5' end regulation region of GFAP was isolated from a 129sv mouse genomic DNA library with PCR-screening. 7.6 kb of pGFAP-Cre-hGH DNA fragment was introduced into 191 fertilized eggs by microinjection. 176 injected eggs were implanted into the oviducts of eight female mice respectively, from which 25 offspring were obtained. Seven mice carry the Cre genes by the identification of PCR and Southern blotting, and the integration efficiency is 28%. The GFAP-Cre transgenic mice were crossed with ROSA26 mice whose genomic DNA is integrated by LoxP sites and LacZ expression frame to check the activity and the tissue-specific expression of Cre recombinase and recombination with its mediation between two LoxP sites. The results of LacZ dying showed that the Cre recombinase was expressed only in CNS and successfully mediated the recombination between the LoxP sites in vivo.