scholarly journals Preclinical Perspectives on Garlic and Cancer

2006 ◽  
Vol 136 (3) ◽  
pp. 827S-831S ◽  
Author(s):  
John A. Milner

ABSTRACT Evidence continues to point to the anticancer properties of fresh garlic extracts, aged garlic, garlic oil, and a number of specific organosulfur compounds generated by processing garlic. These anticarcinogenic and antitumorigenic characteristics appear to arise through both dose- and temporal-related changes in a number of cellular events involved with the cancer process, including those involving drug metabolism, immunocompetence, cell cycle regulation, apoptosis, and angiogenesis. The ability of garlic and related allyl sulfur compounds to block tumors in the colon, lung, breast, and liver suggests general mechanisms that are not tissue specific. Whereas relatively few studies have compared the relative efficacy of water- and lipid-soluble allyl sulfur compounds, those that have when using chemically induced carcinogen models suggest little difference in response, whereas tumor proliferation/apoptosis is highly dependent on the species provided. A shift in sulfhydryl groups, alterations in glutathione:oxidized glutathione ratios, and resultant changes in cellular redox status may be involved in some of the phenotypic changes caused by allyl sulfur compounds. Such changes in thiols by allyl sulfurs may also account for the observed hyperphosphorylation of specific cell cycle proteins and the histone hyperacetylation that has been correlated with suppressed tumor cell proliferation. Whereas the anticarcinogenic and antitumorigenic data to date are impressive, additional studies are needed with more modest exposure to allyl sulfur compounds over prolonged periods. Likewise, additional studies are needed that incorporate transgenic and knockout models to assist in the identification of molecular targets for garlic and its associated allyl sulfur components.

2018 ◽  
Author(s):  
Nicholas L Panchy ◽  
John P. Lloyd ◽  
Shin-Han Shiu

AbstractThe collection all TFs, target genes and their interactions in an organism form a gene regulatory network (GRN), which underly complex patterns of transcription even in unicellular species. However, identifying which interactions regulate expression in a specific temporal context remains a challenging task. With multiple experimental and computational approaches to characterize GRNs, we predicted general and phase-specific cell-cycle expression in Saccharomyces cerevisiae using four regulatory data sets: chromatin immunoprecipitation (ChIP), TF deletion data (Deletion), protein binding microarrays (PBMs), and position weight matrices (PWMs). Our results indicate that the source of regulatory interaction information significantly impacts our ability to predict cell-cycle expression where the best model was constructed by combining selected TF features from ChIP and Deletion data as well as TF-TF interaction features in the form of feed-forward loops. The TFs that were the best predictors of cell-cycle expression were enriched for known cell-cycle regulators but also include regulators not implicated in cell-cycle regulation previously. In addition, ChIP and Deletion datasets led to the identification different subsets of TFs important for predicting cell-cycle expression. Finally, analysis of important TF-TF interaction features suggests that the GRN regulating cell cycle expression is highly interconnected and clustered around four groups of genes, two of which represent known cell-cycle regulatory complexes, while the other two contain TFs that are not known cell-cycle regulators (Ste12-Tex1 and Rap1-Hap1-Msn4), but are nonetheless important to regulating the timing of expression. Thus, not only do our models accurately reflect what is known about the regulation of the S. cerevisiae cell cycle, they can be used to discover regulatory factors which play a role in controlling expression during the cell cycle as well as other contexts with discrete temporal patterns of expression.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Julia Bittmann ◽  
Rokas Grigaitis ◽  
Lorenzo Galanti ◽  
Silas Amarell ◽  
Florian Wilfling ◽  
...  

Cell cycle tags allow to restrict target protein expression to specific cell cycle phases. Here, we present an advanced toolbox of cell cycle tag constructs in budding yeast with defined and compatible peak expression that allow comparison of protein functionality at different cell cycle phases. We apply this technology to the question of how and when Mus81-Mms4 and Yen1 nucleases act on DNA replication or recombination structures. Restriction of Mus81-Mms4 to M phase but not S phase allows a wildtype response to various forms of replication perturbation and DNA damage in S phase, suggesting it acts as a post-replicative resolvase. Moreover, we use cell cycle tags to reinstall cell cycle control to a deregulated version of Yen1, showing that its premature activation interferes with the response to perturbed replication. Curbing resolvase activity and establishing a hierarchy of resolution mechanisms are therefore the principal reasons underlying resolvase cell cycle regulation.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Chengcheng Liu ◽  
Xiaoyan Zhai ◽  
Bin Zhao ◽  
Yanfei Wang ◽  
Zhigang Xu

Abstract In contrast to conventional cyclin-dependent kinases that are important for mitotic cell division, cyclin-dependent kinase 5 (CDK5) is predominantly activated in post-mitotic cells and is involved in various cellular events. The kinase activity of CDK5 is tightly regulated by specific activators including p35, p39, and cyclin I (CCNI). Here we show that cyclin I-like (CCNI2), a homolog of CCNI, interacts with CDK5 and activates the kinase activity of CDK5. Different from CCNI, which colocalizes with CDK5 in the nuclei in transfected cells, CCNI2 mainly retains CDK5 in the cytoplasm as well as on the cell membrane. Furthermore, although the expression level of CCNI2 mRNA and CCNI2 protein do not change significantly during cell cycle, depletion of CCNI2 with siRNA affects cell cycle progression as well as cell proliferation. In conclusion, our data strongly suggest that CCNI2 is a novel CDK5 activator and is involved in cell cycle regulation.


Sign in / Sign up

Export Citation Format

Share Document