Telomeres maintain genomic integrity in normal cells, and their progressive shortening during successive cell divisions induces chromosomal instability. In the large majority of cancer cells, telomere length is maintained by telomerase. Thus, telomere length and telomerase activity are crucial for cancer initiation and the survival of tumors. Several pathways that regulate telomere length have been identified, and genome-scale studies have helped in mapping genes that are involved in telomere length control. Additionally, genomic screening for recurrent human telomerase gene hTERT promoter mutations and mutations in genes involved in the alternative lengthening of telomeres pathway, such as ATRX and DAXX, has elucidated how these genomic changes contribute to the activation of telomere maintenance mechanisms in cancer cells. Attempts have also been made to develop telomere length- and telomerase-based diagnostic tools and anticancer therapeutics. Recent efforts have revealed key aspects of telomerase assembly, intracellular trafficking and recruitment to telomeres for completing DNA synthesis, which may provide novel targets for the development of anticancer agents. Here, we summarize telomere organization and function and its role in oncogenesis. We also highlight genomic mutations that lead to reactivation of telomerase, and mechanisms of telomerase reconstitution and trafficking that shed light on its function in cancer initiation and tumor development. Additionally, recent advances in the clinical development of telomerase inhibitors, as well as potential novel targets, will be summarized.

BackgroundBreast cancer brain metastases (BCBM) develop in about 20–30% of breast cancer (BC) patients. BCBM are associated with dismal prognosis not at least due to lack of valuable molecular therapeutic targets. The aim of the study was to identify new molecular biomarkers and targets in BCBM by using complementary state-of-the-art techniques.MethodsWe compared array expression profiles of three BCBM with 16 non-brain metastatic BC and 16 primary brain tumors (prBT) using a false discovery rate (FDR) p < 0.05 and fold change (FC) > 2. Biofunctional analysis was conducted on the differentially expressed probe sets. High-density arrays were employed to detect copy number variations (CNVs) and whole exome sequencing (WES) with paired-end reads of 150 bp was utilized to detect gene mutations in the three BCBM.ResultsThe top 370 probe sets that were differentially expressed between BCBM and both BC and prBT were in the majority comparably overexpressed in BCBM and included, e.g. the coding genes BCL3, BNIP3, BNIP3P1, BRIP1, CASP14, CDC25A, DMBT1, IDH2, E2F1, MYCN, RAD51, RAD54L, and VDR. A number of small nucleolar RNAs (snoRNAs) were comparably overexpressed in BCBM and included SNORA1, SNORA2A, SNORA9, SNORA10, SNORA22, SNORA24, SNORA30, SNORA37, SNORA38, SNORA52, SNORA71A, SNORA71B, SNORA71C, SNORD13P2, SNORD15A, SNORD34, SNORD35A, SNORD41, SNORD53, and SCARNA22. The top canonical pathway was entitled, role of BRCA1 in DNA damage response. Network analysis revealed key nodes as Akt, ERK1/2, NFkB, and Ras in a predicted activation stage. Downregulated genes in a data set that was shared between BCBM and prBT comprised, e.g. BC cell line invasion markers JUN, MMP3, TFF1, and HAS2. Important cancer genes affected by CNVs included TP53, BRCA1, BRCA2, ERBB2, IDH1, and IDH2. WES detected numerous mutations, some of which affecting BC associated genes as CDH1, HEPACAM, and LOXHD1.ConclusionsUsing complementary molecular genetic techniques, this study identified shared and unshared molecular events in three highly aberrant BCBM emphasizing the challenge to detect new molecular biomarkers and targets with translational implications. Among new findings with the capacity to gain clinical relevance is the detection of overexpressed snoRNAs known to regulate some critical cellular functions as ribosome biogenesis.Electronic supplementary materialThe online version of this article (10.1186/s12967-017-1370-x) contains supplementary material, which is available to authorized users.

BackgroundHepatocellular carcinoma (HCC) accounts for major cancer-related deaths despite current advanced therapies. Treatment and prognosis of HCC is better in patients with preserved liver function. Many natural products including ajwa dates (Phoenix dactylifera L.), are claimed to have hepatoprotective and HCC inhibitory effects, but most lack scientific validation. To prove our hypothesis, we attempted to evaluate the HCC inhibitory effects, and other beneficial properties of the aqueous extract of ajwa dates (ADE) in a rat model of diethylnitrosamine (DEN) induced liver cancer.MethodsThirty-two male rats were divided into four groups of eight each as follows, Group A: untreated control; Group B: DEN control (180 mg/kg bw), Group C: DEN + ADE 0.5 g/kg bw; and Group D: DEN +1.0 g/kg bw. Rats from all groups were assessed for liver cancer progression or inhibition by evaluating histological, biochemical, antioxidant enzyme status, cytokines and gene expression profiles.ResultsDEN treatment Groups (B, C, D) showed histological features of HCC and in rats treated with ADE (Groups C, D) partial to complete reversal of normal liver architecture was observed. Antioxidant enzymes such as superoxide dismutase (SOD), glutathione reductase (GR), glutatione peroxidase (GPx) and catalase (CAT) were increased, while the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels and lipid peroxidation were significantly decreased in Group C and Group D compared to Group B. Pro-inflammatory cytokines such as interleukin (IL)-1α, IL-1β,, GM-CSF) were increased in the serum of rats in Group B while the anti-tumor cytokines (IL-2, IL-12) were increased in ADE treated Groups (C, D). In addition, Alpha-Feto Protein (AFP) and IL-6 gene expression levels were upregulated in Group B, while they were significantly downregulated in ADE treated Groups (C, D).ConclusionsADE helped in the reversal of DEN damaged liver towards normal. Restoration of anti-oxidant enzymes, liver enzymes, cytokines balance and gene expression to normal levels following ADE treatment indicates that ADE improves liver function and inhibits HCC. ADE can, therefore, be used together with conventional therapeutics for HCC.

Cancer cells, stem cells and cancer stem cells have for a long time played a significant role in the biomedical sciences. Though cancer therapy is more effective than it was a few years ago, the truth is that still none of the current non-surgical treatments can cure cancer effectively. The reason could be due to the subpopulation called “cancer stem cells” (CSCs), being defined as those cells within a tumour that have properties of stem cells: self-renewal and the ability for differentiation into multiple cell types that occur in tumours.The phenomenon of CSCs is based on their resistance to many of the current cancer therapies, which results in tumour relapse. Although further investigation regarding CSCs is still needed, there is already evidence that these cells may play an important role in the prognosis of cancer, progression and therapeutic strategy. Therefore, long-term patient survival may depend on the elimination of CSCs. Consequently, isolation of pure CSC populations or reprogramming of cancer cells into CSCs, from cancer cell lines or primary tumours, would be a useful tool to gain an in-depth knowledge about heterogeneity and plasticity of CSC phenotypes and therefore carcinogenesis. Herein, we will discuss current CSC models, methods used to characterize CSCs, candidate markers, characteristic signalling pathways and clinical applications of CSCs. Some examples of CSC-specific treatments that are currently in early clinical phases will also be presented in this review.

In recent years, there is a growing interest in research to investigate the importance of gut microbiome in health and diseases. This opens a new area of research for the role of microbial flora of the human gut in inflammation, energy homeostasis, pathogenesis of obesity and other associated disorders. Recent studies propose association of the gut microbiome with development of obesity and metabolic syndromes, such as type 2 diabetes mellitus (T2DM). The T2DM is a metabolic disease that is mainly caused by obesity-linked insulin resistance. The vascular effects of obesity appears to play a role in the development of Alzheimer's disease (AD) that is one of the rapidly growing diseases of a late stage of life all over the world. Studies from both humans and mice models have been demonstrated the engagement of gut microbial flora in the pathogenesis of obesity and host metabolism. The aim of this review is to discuss the current findings that may explain the cascade of gut microbial flora participation in the development of obesity, T2DM and further initiation of AD. In addition, the available data regarding the mechanisms that have been proposed to elucidate the role of gut microbiota in weight gain and possible cause of T2DM and AD have been examined.