Deregulation of cell death in cancer: Recent highlights

The aim of this Special Issue on the deregulation of cell death in cancer is to bring together recent perspectives on the relationship between tumorigenesis and programmed cell death (PCD) [...]

Design of dual inhibitors of histone deacetylase 6 and heat shock protein 90

Histone deacetylase 6 (HDAC6) and heat shock protein 90 (Hsp90) are widely investigated anticancer drug targets. Importantly, several lines of evidence indicate that their regulation and activity are intimately linked, and that their combined inhibition may lead to impressive therapeutic benefits. In this study, we developed and applied an integrated computational strategy to design dual inhibitors of HDAC6 and Hsp90. Although the two targets share very little homology, an integrated ligand-based and structure-based virtual screening approach indicated a subset of compounds possessing the key structural requirements for binding at both targets. In vitro tests demonstrated that some of the selected candidates are able to selectively inhibit HDAC6 over HDAC1, to increase the acetylation levels of tubulin on cell assays and to reduce cell proliferation. The discovered compounds represent valuable starting points for further hit optimization

Single-Cell Photothermal Analysis Induced by MoS2 Nanoparticles by Raman Spectroscopy

Two-dimensional nanomaterials, such as MoS2 nanosheets, have been attracting increasing attention in cancer diagnosis and treatment, thanks to their peculiar physical and chemical properties. Although the mechanisms which regulate the interaction between these nanomaterials and cells are not yet completely understood, many studies have proved their efficient use in the photothermal treatment of cancer, and the response to MoS2 nanosheets at the single-cell level is less investigated. Clearly, this information can help in shedding light on the subtle cellular mechanisms ruling the interaction of this 2D material with cells and, eventually, to its cytotoxicity. In this study, we use confocal micro-Raman spectroscopy to reconstruct the thermal map of single cells targeted with MoS2 under continuous laser irradiation. The experiment is performed by analyzing the water O-H stretching band around 3,400 cm−1 whose tetrahedral structure is sensitive to the molecular environment and temperature. Compared to fluorescence-based approaches, this Raman-based strategy for temperature measurement does not suffer fluorophore instability, which can be significant under continuous laser irradiation. We demonstrate that irradiation of human breast cancer MCF7 cells targeted with MoS2 nanosheets causes a relevant photothermal effect, which is particularly high in the presence of MoS2 nanosheet aggregates. Laser-induced heating is strongly localized near such particles which, in turn, tend to accumulate near the cytoplasmic membrane. Globally, our experimental outcomes are expected to be important for tuning the nanosheet fabrication process

A combinatorial approach to gene expression analysis: DNA microarrays.

The microarray technology is based on analytical tools that parallelize the quantitative and qualitative analysis of nucleic acids, proteins and tissue sections one of its more recent evolutions-. By miniaturizing the size of the reaction and sensing area, microarrays allow to assess at the activity of thousands of genes in a given tissue or cell line at once in a rapid and quantitative way, and to carry out serial comparative tests in multiple samples. These tools, that stem from the innovations resulting from the technological improvements and knowledge arising from the genome sequencing projects, can be considered as a combinatorial technique that can rapidly provide significant information about complex cellular pathways and processes within one or few ‘‘mass scale’’ and comprehensive testing of a biological sample’s composition

Molecular docking simulations on histone deacetylases (Hdac)-1 and-2 to investigate the flavone binding

Histone modifications through acetylation are fundamental for remodelling chromatin and consequently activating gene expression. The imbalance between acetylation and deacetylation activity causes transcriptional dysregulation associated with several disorders. Flavones, small molecules of plant origin, are known to interfere with class I histone deacetylase (HDAC) enzymes and to enhance acetylation, restoring cell homeostasis. To investigate the possible physical interactions of flavones on human HDAC1 and 2, we carried out in silico molecular docking simulations. Our data have revealed how flavone, and other two flavones previously investigated, i.e., apigenin and luteolin, can interact as ligands with HDAC1 and 2 at the active site binding pocket. Regulation of HDAC activity by dietary flavones could have important implications in developing epigenetic therapy to regulate the cell gene expression

KDM4 Involvement in Breast Cancer and Possible Therapeutic Approaches

Breast cancer (BC) is the second leading cause of cancer death in women, although recent scientific and technological achievements have led to significant improvements in progression-free disease and overall survival of patients. Genetic mutations and epigenetic modifications play a critical role in deregulating gene expression, leading to uncontrolled cell proliferation and cancer progression. Aberrant histone modifications are one of the most frequent epigenetic mechanisms occurring in cancer. In particular, methylation and demethylation of specific lysine residues alter gene accessibility via histone lysine methyltransferases (KMTs) and histone lysine demethylases (KDMs). The KDM family includes more than 30 members, grouped into six subfamilies and two classes based on their sequency homology and catalytic mechanisms, respectively. Specifically, the KDM4 gene family comprises six members, KDM4A-F, which are associated with oncogene activation, tumor suppressor silencing, alteration of hormone receptor downstream signaling, and chromosomal instability. Blocking the activity of KDM4 enzymes renders them “druggable” targets with therapeutic effects. Several KDM4 inhibitors have already been identified as anticancer drugs in vitro in BC cells. However, no KDM4 inhibitors have as yet entered clinical trials due to a number of issues, including structural similarities between KDM4 members and conservation of the active domain, which makes the discovery of selective inhibitors challenging. Here, we summarize our current knowledge of the molecular functions of KDM4 members in BC, describe currently available KDM4 inhibitors, and discuss their potential use in BC therapy

Extracellular vesicle-based nucleic acid delivery: Current advances and future perspectives in cancer therapeutic strategies

Extracellular vesicles (EVs) are sophisticated and sensitive messengers released by cells to communicate with and influence distant and neighboring cells via selective transfer of bioactive content, including protein lipids and nucleic acids. EVs have therefore attracted broad interest as new and refined potential therapeutic systems in many diseases, including cancer, due to their low immunogenicity, non-toxicity, and elevated bioavailability. They might serve as safe and effective vehicles for the transport of therapeutic molecules to specific tissues and cells. In this review, we focus on EVs as a vehicle for gene therapy in cancer. We describe recent developments in EV engineering to achieve efficient intracellular delivery of cancer therapeutics and avoid off-target effects, to provide an overview of the potential applications of EV-mediated gene therapy and the most promising biomedical advances

The cannabinoid receptor cb1 stabilizes sperm chromatin condensation status during epididymal transit by promoting disulphide bond formation

The cannabinoid receptor CB1 regulates differentiation of spermatids. We recently characterized spermatozoa from caput epididymis of CB1-knock-out mice and identified a considerable number of sperm cells with chromatin abnormality such as elevated histone content and poorly condensed chromatin. In this paper, we extended our findings and studied the role of CB1 in the epididymal phase of chromatin condensation of spermatozoa by analysis of spermatozoa from caput and cauda epididymis of wild-type and CB1-knock-out mouse in both a homozygous or heterozygous condition. Furthermore, we studied the impact of CB1-gene deletion on histone displacement mechanism by taking into account the hyperacetylation of histone H4 and players of displacement such as Chromodomain Y Like protein (CDYL) and Bromodomain testis-specific protein (BRDT). Our results show that CB1, via local and/or endocrine cell-to-cell signaling, modulates chromatin remodeling mechanisms that orchestrate a nuclear condensation extent of mature spermatozoa. We show that CB1-gene deletion affects the epididymal phase of chromatin condensation by interfering with inter-/intra-protamine disulphide bridges formation, and deranges the efficiency of histone removal by reducing the hyper-acetylation of histone H4. This effect is independent by gene expression of Cdyl and Brdt mRNA. Our results reveal a novel and important role for CB1 in sperm chromatin condensation mechanisms

Fetal-Perinatal Exposure to Bisphenol-A Affects Quality of Spermatozoa in Adulthood Mouse

Bisphenol-A (BPA) is considered an endocrine disruptor with estrogenic activity. It is described as an environment-polluting industrial chemical whose adverse effects on the male reproductive system depend on the period of exposure (i.e., fetal, prepubertal, or adult life). We exposed male mice to BPA during the fetal-perinatal period (from 10 days post coitum to 31 days post partum) and investigated the impact of this early-life exposure on gamete health in adulthood animals at 78 days of age. Both in control and BPA-exposed mice, viability and motility of spermatozoa, as well as sperm motility acquisition and chromatin condensation of spermatozoa, have been evaluated. Results reveal harmful effect of BPA on viability and motility of sperm cells as well as on chromatin condensation status during epididymal maturation of spermatozoa. In particular, BPA exposure interferes with biochemical mechanism useful to stabilize sperm chromatin condensation, as it interferes with oxidation of thiol groups associated to chromatin