19 research outputs found
Crosstalk between long non coding RNAs, microRNAs and DNA damage repair in prostate cancer: new therapeutic opportunities?
It is increasingly appreciated that transcripts derived from non-coding parts of the human genome, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), are key regulators of biological processes both in normal physiology and disease. Their dysregulation during tumourigenesis has attracted significant interest in their exploitation as novel cancer therapeutics. Prostate cancer (PCa), as one of the most diagnosed malignancies and a leading cause of cancer-related death in men, continues to pose a major public health problem. In particular, survival of men with metastatic disease is very poor. Defects in DNA damage response (DDR) pathways culminate in genomic instability in PCa, which is associated with aggressive disease and poor patient outcome. Treatment options for metastatic PCa remain limited. Thus, researchers are increasingly targeting ncRNAs and DDR pathways to develop new biomarkers and therapeutics for PCa. Increasing evidence points to a widespread and biologically-relevant regulatory network of interactions between lncRNAs and miRNAs, with implications for major biological and pathological processes. This review summarises the current state of knowledge surrounding the roles of the lncRNA:miRNA interactions in PCa DDR, and their emerging potential as predictive and diagnostic biomarkers. We also discuss their therapeutic promise for the clinical management of PCa
VASCULAR PERMEABILITY- INCREASING EFFECT OF THE LEAF ESSENTIAL OIL OF OCIMUM GRATISSIMUM LINN AS A MECHANISM FOR ITS WOUND HEALING PROPERTY.
Persistent microvascular hyperpermeability to plasma proteins is a characteristic feature of normal wound healing. Does the leaf essential oil of Ocimum gratissimum heal wounds by promoting this feature? Evanâs blue dye (20mg/kg body weight) in normal saline was administered intravenously through marginal ear vein of experimental rabbits (n=5). Each animal served as its own control. One hour after Evanâs blue dye administration, 0.1ml each of Ocimum oil, histamine dihydrochloride (30”g/ml) and normal saline were randomly administered by intra-dermal injection at the prepared sites on each of the animals. Increase in vascular permeability was assessed by dye effusion test. Analysis of the differences in vascular permeability between treatment groups showed that, Ocimum oil, in intensity and duration, was significantly (
A non-coding RNA balancing act: miR-346-induced DNA damage is limited by the long non-coding RNA NORAD in prostate cancer
Background: miRâ346 was identified as an activator of Androgen Receptor (AR) signalling that associates with DNA damage response (DDR)âlinked transcripts in prostate cancer (PC). We sought to delineate the impact of miRâ346 on DNA damage, and its potential as a therapeutic agent. Methods: RNAâIP, RNAâseq, RNAâISH, DNA fibre assays, in vivo xenograft studies and bioinformatics approaches were used alongside a novel method for amplificationâfree, single nucleotideâresolution genomeâwide mapping of DNA breaks (INDUCEâseq). Results: miRâ346 induces rapid and extensive DNA damage in PC cells â the first report of microRNAâinduced DNA damage. Mechanistically, this is achieved through transcriptional hyperactivation, Râloop formation and replication stress, leading to checkpoint activation and cell cycle arrest. miRâ346 also interacts with genomeâprotective lncRNA NORAD to disrupt its interaction with PUM2, leading to PUM2 stabilisation and its increased turnover of DNA damage response (DDR) transcripts. Confirming clinical relevance, NORAD expression and activity strongly correlate with poor PC clinical outcomes and increased DDR in biopsy RNAâseq studies. In contrast, miRâ346 is associated with improved PC survival. INDUCEâseq reveals that miRâ346âinduced DSBs occur preferentially at binding sites of the most highlyâtranscriptionally active transcription factors in PC cells, including câMyc, FOXA1, HOXB13, NKX3.1, and importantly, AR, resulting in target transcript downregulation. Further, RNAâseq reveals widespread miRâ346 and shNORAD dysregulation of DNA damage, replication and cell cycle processes. NORAD drives targetâdirected miR decay (TDMD) of miRâ346 as a novel genome protection mechanism: NORAD silencing increases mature miRâ346 levels by several thousandâfold, and WT but not TDMDâmutant NORAD rescues miRâ346âinduced DNA damage. Importantly, miRâ346 sensitises PC cells to DNAâdamaging drugs including PARP inhibitor and chemotherapy, and induces tumour regression as a monotherapy in vivo, indicating that targeting miRâ346:NORAD balance is a valid therapeutic strategy
Choline kinase alpha as an androgen receptor chaperone and prostate cancer therapeutic target
Background: The androgen receptor (AR) is a major drug target in prostate cancer (PCa). We profiled the AR-regulated kinome to identify clinically relevant and druggable effectors of AR signaling. Methods: Using genome-wide approaches, we interrogated all AR regulated kinases. Among these, choline kinase alpha (CHKA) expression was evaluated in benign (n = 195), prostatic intraepithelial neoplasia (PIN) (n = 153) and prostate cancer (PCa) lesions (n = 359). We interrogated how CHKA regulates AR signaling using biochemical assays and investigated androgen regulation of CHKA expression in men with PCa, both untreated (n = 20) and treated with an androgen biosynthesis inhibitor degarelix (n = 27). We studied the effect of CHKA inhibition on the PCa transcriptome using RNA sequencing and tested the effect of CHKA inhibition on cell growth, clonogenic survival and invasion. Tumor xenografts (n = 6 per group) were generated in mice using genetically engineered prostate cancer cells with inducible CHKA knockdown. Data were analyzed with Ï 2 tests, Cox regression analysis, and Kaplan-Meier methods. All statistical tests were two-sided. Results: CHKA expression was shown to be androgen regulated in cell lines, xenografts, and human tissue (log fold change from 6.75 to 6.59, P = .002) and was positively associated with tumor stage. CHKA binds directly to the ligand-binding domain (LBD) of AR, enhancing its stability. As such, CHKA is the first kinase identified as an AR chaperone. Inhibition of CHKA repressed the AR transcriptional program including pathways enriched for regulation of protein folding, decreased AR protein levels, and inhibited the growth of PCa cell lines, human PCa explants, and tumor xenografts. Conclusions: CHKA can act as an AR chaperone, providing, to our knowledge, the first evidence for kinases as molecular chaperones, making CHKA both a marker of tumor progression and a potential therapeutic target for PCa.Mohammad Asim ... Luke A. Selth ... Wayne D. Tilley et al
A reciprocal feedback between the PDZ binding kinase and androgen receptor drives prostate cancer
Elucidation of mechanisms underlying the increased androgen receptor (AR) activity and subsequent development of aggressive prostate cancer (PrCa) is pivotal in developing new therapies. Using a systems biology approach, we interrogated the AR-regulated proteome and identified PDZ binding kinase (PBK) as a novel AR-regulated protein that regulates full-length AR and AR variants (ARVs) activity in PrCa. PBK overexpression in aggressive PrCa is associated with early biochemical relapse and poor clinical outcome. In addition to its carboxy terminus ligand-binding domain, PBK directly interacts with the amino terminus transactivation domain of the AR to stabilise it thereby leading to increased AR protein expression observed in PrCa. Transcriptome sequencing revealed that PBK is a mediator of global AR signalling with key roles in regulating tumour invasion and metastasis. PBK inhibition decreased growth of PrCa cell lines and clinical specimen cultured ex vivo. We uncovered a novel interplay between AR and PBK that results in increased AR and ARVs expression that executes AR-mediated growth and progression of PrCa, with implications for the development of PBK inhibitors for the treatment of aggressive PrCa.Anne Y. Warren, Charlie E. Massie, Kate Watt, Katarina Luko ... Luke A. Selth ... Wayne D. Tilley ... et al
Research Paper - VASCULAR PERMEABILITY- INCREASING EFFECT OF THE LEAF ESSENTIAL OIL OF OCIMUM GRATISSIMUM LINN AS A MECHANISM FOR ITS WOUND HEALING PROPERTY.
Persistent microvascular hyperpermeability to plasma proteins is a
characteristic feature of normal wound healing. Does the leaf essential
oil of Ocimum gratissimum heal wounds by promoting this
feature? Evan's blue dye (20mg/kg body weight) in normal saline was
administered intravenously through marginal ear vein of experimental
rabbits (n=5). Each animal served as its own control. One hour after
Evan's blue dye administration, 0.1ml each of Ocimum oil, histamine
dihydrochloride (30ÎŒg/ml) and normal saline were randomly
administered by intra-dermal injection at the prepared sites on each of
the animals. Increase in vascular permeability was assessed by dye
effusion test. Analysis of the differences in vascular permeability
between treatment groups showed that, Ocimum oil, in intensity and
duration, was significantly (p<.05) more effective in increasing
cutaneous capillary permeability over a 24h period after treatment. The
ability of Ocimum oil in increasing vascular permeability may be one of
the factors that contribute to its wound healing property
RHEOLOGICAL PROPERTIES OF AQUEOUS SOLUTIONS OF THE GUMMY EXUDATE OF ZANTHOXYLUM TESSMANNII
A non-coding RNA balancing act: miR-346-induced DNA damage is limited by the long non-coding RNA NORAD in prostate cancer
Background
miR-346 was identified as an activator of Androgen Receptor (AR) signalling that associates with DNA damage response (DDR)-linked transcripts in prostate cancer (PC). We sought to delineate the impact of miR-346 on DNA damage, and its potential as a therapeutic agent.
Methods
RNA-IP, RNA-seq, RNA-ISH, DNA fibre assays, in vivo xenograft studies and bioinformatics approaches were used alongside a novel method for amplification-free, single nucleotide-resolution genome-wide mapping of DNA breaks (INDUCE-seq).
Results
miR-346 induces rapid and extensive DNA damage in PC cells - the first report of microRNA-induced DNA damage. Mechanistically, this is achieved through transcriptional hyperactivation, R-loop formation and replication stress, leading to checkpoint activation and cell cycle arrest. miR-346 also interacts with genome-protective lncRNA NORAD to disrupt its interaction with PUM2, leading to PUM2 stabilisation and its increased turnover of DNA damage response (DDR) transcripts. Confirming clinical relevance, NORAD expression and activity strongly correlate with poor PC clinical outcomes and increased DDR in biopsy RNA-seq studies. In contrast, miR-346 is associated with improved PC survival.
INDUCE-seq reveals that miR-346-induced DSBs occur preferentially at binding sites of the most highly-transcriptionally active transcription factors in PC cells, including c-Myc, FOXA1, HOXB13, NKX3.1, and importantly, AR, resulting in target transcript downregulation. Further, RNA-seq reveals widespread miR-346 and shNORAD dysregulation of DNA damage, replication and cell cycle processes.
NORAD drives target-directed miR decay (TDMD) of miR-346 as a novel genome protection mechanism: NORAD silencing increases mature miR-346 levels by several thousand-fold, and WT but not TDMD-mutant NORAD rescues miR-346-induced DNA damage. Importantly, miR-346 sensitises PC cells to DNA-damaging drugs including PARP inhibitor and chemotherapy, and induces tumour regression as a monotherapy in vivo, indicating that targeting miR-346:NORAD balance is a valid therapeutic strategy.
Conclusions
A balancing act between miR-346 and NORAD regulates DNA damage and repair in PC. miR-346 may be particularly effective as a therapeutic in the context of decreased NORAD observed in advanced PC, and in transcriptionally-hyperactive cancer cells