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Increasing evidence supports the involvement of DNA damage in several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Elevated levels of DNA damage are consistently observed in both sporadic and familial forms of ALS and may also play a role in Western Pacific ALS, which is thought to have an environmental cause. The cause of DNA damage in ALS remains unclear but likely differs between genetic subgroups. Repeat expansion in the C9ORF72 gene is the most common genetic cause of familial ALS and responsible for about 10% of sporadic cases. These genetic mutations are known to cause R-loops, thus increasing genomic instability and DNA damage, and generate dipeptide repeat proteins, which have been shown to lead to DNA damage and impairment of the DNA damage response. Similarly, several genes associated with ALS including TARDBP, FUS, NEK1, SQSTM1 and SETX are known to play a role in DNA repair and the DNA damage response, and thus may contribute to neuronal death via these pathways. Another consistent feature present in both sporadic and familial ALS is the ability of astrocytes to induce motor neuron death, although the factors causing this toxicity remain largely unknown. In this review, we summarise the evidence for DNA damage playing a causative or secondary role in the pathogenesis of ALS as well as discuss the possible mechanisms involved in different genetic subtypes with particular focus on the role of astrocytes initiating or perpetuating DNA damage in neurons.

Skeletal muscles undergo macroscopic changes, including atrophy and myosteatosis, alongside microscopic changes in their phenotype due to ageing. Sarcopenia is a muscle disease that affects older people and is characterised by the progressive loss of skeletal muscle, resulting in reduced muscle function and a decrease in quality of life. A lack of early diagnosis increases the risk of immobility and disability; highlighting the need for effective early indicators and interventions to prevent disease progression and improve muscle health. Following the onset of sarcopenia current treatment relies upon a progressive resistance training (RT) programme to promote muscle hypertrophy and improve physical performance by the upregulation of protein synthesis and the increase in type II muscle fibre size. However, RT is not appropriate for all patients, and is infrequently integrated into medicine or social care for older people. Alternative interventions to RT include multi-modal training, low-intensity blood-flow restriction training, and whole-body vibration training. Understanding the macroscopic and microscopic changes in the skeletal muscle in response to different interventions is essential to recognising their validity and further utility as a preventative intervention. Unfortunately, these changes are yet to be elucidated within the literature. Once effective exercise interventions have been established, barriers to exercise need to be identified and resolved. This will ensure that effective interventions are easily accessible for those who are diagnosed or at risk of developing sarcopenia.

Taxane is a family of front-line chemotherapeutic agents against ovarian cancer (OC). The therapeutic efficacy is frequently counteracted by the development of chemoresistance, leading to high rates of relapse in OC patients. The role(s) of microRNAs (miRNAs) in cancer chemoresistance had been supported by many evidences Epigenetic regulation by miRNAs has been reported to influence cancer development and response to therapeutics, however, their role in OC resistance to paclitaxel (PTX) is unclear. Here, we conducted miRNA profiling in the responsive and PTX-resistant OC cell lines before and after treatment with epigenetic modulators. We reveal 157 miRNAs to be downregulated in the PTX-resistant cells compared to parental controls. The expression of five miRNAs (miRNA-7-5p, -204-3p, -501-5p, -3652 and -4286) was restored after epigenetic modulation, which was further confirmed by qPCR. In silico analysis of the signaling pathways targeted by the selected miRNAs identified the PI3K-AKT pathway as the primary target. Subsequent cDNA array analysis confirmed multiple PI3K-AKT pathway members such as AKT2, PIK3R3, CDKN1A, CCND2 and FGF2 to be upregulated in PTX-resistant cells. STRING analysis showed the deregulated genes in PTX-resistant cells to be primarily involved in cell cycle progression and survival. Thus, high throughput miRNA and cDNA profiling coupled with pathway analysis and data mining provide evidence for epigenetically regulated miRNAs-induced modulation of signaling pathways in PTX resistant OC cells. It paves the way to more in-depth mechanistic studies and new therapeutic strategies to combat chemoresistance.

Summary Human pluripotent stem cells (PSCs) are subject to the appearance of recurrent genetic variants on prolonged culture. We have now found that, compared with isogenic differentiated cells, PSCs exhibit evidence of considerably more DNA damage during the S phase of the cell cycle, apparently as a consequence of DNA replication stress marked by slower progression of DNA replication, activation of latent origins of replication, and collapse of replication forks. As in many cancers, which, like PSCs, exhibit a shortened G1 phase and DNA replication stress, the resulting DNA damage may underlie the higher incidence of abnormal and abortive mitoses in PSCs, resulting in chromosomal non-dysjunction or cell death. However, we have found that the extent of DNA replication stress, DNA damage, and consequent aberrant mitoses can be substantially reduced by culturing PSCs in the presence of exogenous nucleosides, resulting in improved survival, clonogenicity, and population growth., Highlights • Human pluripotent stem cells are susceptible to replication stress • Nucleosides modulate replication stress and DNA damage in human PSCs • Nucleosides alleviate mitotic errors and improve the growth kinetics of human PSCs • These findings provide a means to reduce the incidence of recurrent genetic change, Halliwell et al. document the susceptibility of human PSCs to replication stress, which may lead to genetic instability. The results presented show that this phenotype can be moderated by culture in the presence of exogenous nucleosides. The findings provide an approach to reducing the incidence of recurrent genetic changes that may compromise the use of human PSCs in regenerative medicine.

When the ‘CO-releasing molecule-3’, CORM-3 (Ru(CO)3Cl(glycinate)), is dissolved in water it forms a range of ruthenium complexes. These are taken up by cells and bind to intracellular ligands, notably thiols such as cysteine and glutathione, where the Ru(II) reaches high intracellular concentrations. Here, we show that the Ru(II) ion also binds to DNA, at exposed guanosine N7 positions. It therefore has a similar cellular target to the anticancer drug cisplatin, but not identical, because Ru(II) shows no evidence of forming intramolecular crossbridges in the DNA. The reaction is slow, and with excess Ru, intermolecular DNA crossbridges are formed. The addition of CORM-3 to human colorectal cancer cells leads to strand breaks in the DNA, as assessed by the alkaline comet assay. DNA damage is inhibited by growth media containing amino acids, which bind to extracellular Ru and prevent its entry into cells. We conclude that the cytotoxicity of Ru(II) is different from that of platinum, making it a promising development target for cancer therapeutics.

Topoisomerase1 (TOP1)-mediated chromosomal breaks are endogenous sources of DNA damage that affect neuronal genome stability. Whether TOP1 DNA breaks are sources of genomic instability in Huntington’s disease (HD) is unknown. Here, we report defective 53BP1 recruitment in multiple HD cell models, including striatal neurons derived from HD patients. Defective 53BP1 recruitment is due to reduced H2A ubiquitination caused by the limited RNF168 activity. The reduced availability of RNF168 is caused by an increased interaction with p62, a protein involved in selective autophagy. Depletion of p62 or disruption of the interaction between RNAF168 and p62 was sufficient to restore 53BP1 enrichment and subsequent DNA repair in HD models, providing new opportunities for therapeutic interventions. These findings are reminiscent to what was described for p62 accumulation caused by C9orf72 expansion in ALS/FTD and suggest a common mechanism by which protein aggregation perturb DNA repair signaling.

The DNA Damage Response (DDR) pathways sense DNA damage and coordinate robust DNA repair and bypass mechanisms. A series of repair proteins are recruited depending on the type of breaks and lesions to ensure overall survival. An increase in glucose levels was shown to induce genome instability, yet the links between DDR and glucose are still not well investigated. In this study, we aimed to identify dysregulation in the transcriptome of normal and cancerous breast cell lines upon changing glucose levels. We first performed bioinformatics analysis using a microarray dataset containing the triple-negative breast cancer (TNBC) MDA-MB-231 and the normal human mammary epithelium MCF10A cell lines grown in high glucose (HG) or in the presence of the glycolysis inhibitor 2-deoxyglucose (2DG). Interestingly, multiple DDR genes were significantly upregulated in both cell lines grown in HG. In the wet lab, we remarkably found that HG results in severe DNA damage to TNBC cells as observed using the comet assay. In addition, several DDR genes were confirmed to be upregulated using qPCR analysis in the same cell line. Our results propose a strong need for DDR pathways in the presence of HG to oppose the severe DNA damage induced in cells.

Technological advancements in the present era have enhanced drug discovery and development. Nanomedicines are valuable pharmacotherapeutic tools against several diseases and disorders including aging related disorders. The mechanistic association between nanomedicines and molecular modulation have been investigated by many researchers. Notwithstanding the availability of tremendous amount of data, role of nanomedicines in aging related disorders intending inflammasome transfiguration have not been thoroughly reviewed till now. In the present review, we discuss the application of nanomedicines in aging related disorders. Further, we highlight the recent updates on modulated upstream and downstream signalling molecules of inflammasome cascade due to nanomedicines. The review will benefit researchers targeting nanomedicines as a therapeutic approach towards treatment age related disorders through inflammasome inflection.

Spinal muscular atrophy, the leading genetic cause of infant mortality, is a motor neuron disease caused by low levels of survival motor neuron (SMN) protein. SMN is a multifunctional protein that is implicated in numerous cytoplasmic and nuclear processes. Recently, increasing attention is being paid to the role of SMN in the maintenance of DNA integrity. DNA damage and genome instability have been linked to a range of neurodegenerative diseases. The ribosomal DNA (rDNA) represents a particularly unstable locus undergoing frequent breakage. Instability in rDNA has been associated with cancer, premature ageing syndromes, and a number of neurodegenerative disorders. Here, we report that SMN-deficient cells exhibit increased rDNA damage leading to impaired ribosomal RNA synthesis and translation. We also unravel an interaction between SMN and RNA polymerase I. Moreover, we uncover an spinal muscular atrophy motor neuron-specific deficiency of DDX21 protein, which is required for resolving R-loops in the nucleolus. Taken together, our findings suggest a new role of SMN in rDNA integrity.

As we age, our bodies accrue damage in the form of DNA mutations. These mutations lead to the generation of sub-optimal proteins, resulting in inadequate cellular homeostasis and senescence. The build-up of senescent cells negatively affects the local cellular micro-environment and drives ageing associated disease, including neurodegeneration. Therefore, limiting the accumulation of DNA damage is essential for healthy neuronal populations. The naked mole rats (NMR) are from eastern Africa and can live for over three decades in chronically hypoxic environments. Despite their long lifespan, NMRs show little to no biological decline, neurodegeneration, or senescence. Here, we discuss molecular pathways and adaptations that NMRs employ to maintain genome integrity and combat the physiological and pathological decline in organismal function.

The genome of living organisms frequently undergoes various types of modifications which are recognized and repaired by the relevant repair mechanisms. These repair pathways are increasingly being deciphered to understand the mechanisms. Base excision repair (BER) is indispensable to maintain genome stability. One of the enigmatic repair proteins of BER, Apurinic/Apyrimidinic Endonuclease 2 (APE2), like APE1, is truly multifunctional and demonstrates the independent and non-redundant function in maintaining the genome integrity. APE2 is involved in ATR-Chk1 mediated DNA damage response. It also resolves topoisomerase1 mediated cleavage complex intermediate which is formed while repairing misincorporated ribonucleotides in the absence of functional RNase H2 mediated excision repair pathway. BER participates in the demethylation pathway and the role of Arabidopsis thaliana APE2 is demonstrated in this process. Moreover, APE2 is synthetically lethal to BRCA1, BRCA2, and RNase H2, and its homolog, APE1 fails to complement the function. Hence, the role of APE2 is not just an alternate to the repair mechanisms but has implications in diverse functional pathways related to the maintenance of genome integrity. This review analyses genomic features of APE2 and delineates its enzyme function as error-prone as well as efficient and accurate repair protein based on the studies on mammalian or its homolog proteins from model systems such as Arabidopsis thaliana, Schizosaccharomyces pombe, Trypanosoma curzi, Xenopus laevis, Danio rerio, Mus musculus, and Homo sapiens.

Simple Summary Targeting topoisomerases has been widely used as anticancer therapeutics. Exposure to high temperature (hyperthermia) protects cells from the cytotoxic effect of topoisomerase-targeting therapeutics, yet the mechanism remains unknown. Here, we report that hyperthermia inhibits the nucleolytic processing of topoisomerase-induced DNA damage and drives repair to a more faithful pathway mediated by TDP1 and TDP2. We further show that hyperthermia suppresses topoisomerase-induced chromosomal translocation and hallmarks of inflammation, which has broad implications in cancer development and therapy. Abstract Cancer-causing mutations often arise from inappropriate DNA repair, yet acute exposure to DNA damage is widely used to treat cancer. The challenge remains in how to specifically induce excessive DNA damage in cancer cells while minimizing the undesirable effects of genomic instability in noncancerous cells. One approach is the acute exposure to hyperthermia, which suppresses DNA repair and synergizes with radiotherapy and chemotherapy. An exception, however, is the protective effect of hyperthermia on topoisomerase targeting therapeutics. The molecular explanation for this conundrum remains unclear. Here, we show that hyperthermia suppresses the level of topoisomerase mediated single- and double-strand breaks induced by exposure to topoisomerase poisons. We further uncover that, hyperthermia suppresses hallmarks of genomic instability induced by topoisomerase targeting therapeutics by inhibiting nuclease activities, thereby channeling repair to error-free pathways driven by tyrosyl-DNA phosphodiesterases. These findings provide an explanation for the protective effect of hyperthermia from topoisomerase-induced DNA damage and may help to explain the inverse relationship between cancer incidence and temperature. They also pave the way for the use of controlled heat as a therapeutic adjunct to topoisomerase targeting therapeutics.

Simple Summary Glioblastomas are high-grade brain tumours and are the most common form of malignancy arising in the brain. Patient survival has improved little over the last 40 years, highlighting an urgent unmet need for more effective treatments for these tumours. Current standard-of-care treatment involves surgical removal of as much of the tumour as possible followed by a course of chemo-/radiotherapy. The main chemotherapeutic drug used is called temozolomide, however even with this treatment regimen, the average patient survival following diagnosis is around 15 months. We have identified a protein called ERK5 which is present at higher levels in these high-grade brain tumours compared to normal brain tissue, and which is also associated with resistance to temozolomide and poor patient survival. Additionally, we show that targeting ERK5 in brain tumour cells can improve the effectiveness of temozolomide in killing these tumour cells and offers potential much-needed future clinical benefit to patients diagnosed with glioblastoma. Abstract Brain tumours kill more children and adults under 40 than any other cancer, with approximately half of primary brain tumours being diagnosed as high-grade malignancies known as glioblastomas. Despite de-bulking surgery combined with chemo-/radiotherapy regimens, the mean survival for these patients is only around 15 months, with less than 10% surviving over 5 years. This dismal prognosis highlights the urgent need to develop novel agents to improve the treatment of these tumours. To address this need, we carried out a human kinome siRNA screen to identify potential drug targets that augment the effectiveness of temozolomide (TMZ)—the standard-of-care chemotherapeutic agent used to treat glioblastoma. From this we identified ERK5/MAPK7, which we subsequently validated using a range of siRNA and small molecule inhibitors within a panel of glioma cells. Mechanistically, we find that ERK5 promotes efficient repair of TMZ-induced DNA lesions to confer cell survival and clonogenic capacity. Finally, using several glioblastoma patient cohorts we provide target validation data for ERK5 as a novel drug target, revealing that heightened ERK5 expression at both the mRNA and protein level is associated with increased tumour grade and poorer patient survival. Collectively, these findings provide a foundation to develop clinically effective ERK5 targeting strategies in glioblastomas and establish much-needed enhancement of the therapeutic repertoire used to treat this currently incurable disease.

The repair of protein-linked chromosomal breaks requires distinct factors throughout the life span., Deficiency in the DNA end-processing enzyme, tyrosyl-DNA phosphodiesterase 1 (TDP1), causes progressive neurodegeneration in humans. Here, we generated a tdp1 knockout zebrafish and confirmed the lack of TDP1 activity. In adulthood, homozygotes exhibit hypersensitivity to topoisomerase 1 (Top1) poisons and a very mild locomotion defect. Unexpectedly, embryonic tdp1−/− zebrafish were not hypersensitive to Top1 poisons and did not exhibit increased Top1-DNA breaks. This is in contrast to the hypersensitivity of Tdp1-deficient vertebrate models reported to date. Tdp1 is dispensable in the zebrafish embryo with transcript levels down-regulated in response to Top1-DNA damage. In contrast, apex2 and ercc4 (xpf) transcripts were up-regulated. These findings identify the tdp1−/− zebrafish embryo as the first vertebrate model that does not require Tdp1 to protect from Top1-DNA damage and identify apex2 and ercc4 (xpf) as putative players fulfilling this role. It highlights the requirement of distinct DNA repair factors across the life span of vertebrates.

Several semisynthetic analogs of camptothecin (CPT) are used clinically for the treatment of various types of cancers, including colorectal (CRC) cancer, despite their severe, potentially life-threatening toxicities. Studies defined key mutations in the UDP-glycosyltransferase 1 polypeptide A1 (UGT1A1) gene in CRC which play a role in the toxicity and resistance of a broad class of anti-cancer drugs that target DNA topoisomerases. UGT-1A1 is responsible for the glucuronidation and detoxification of the active/toxic metabolite of the topoisomerase I poison, CPT and its analogues, SN-38. Herein, we investigated the potential chemomodulatory effects of a UGT1A1-gene inducer, phenytoin, to the anticancer properties of CPT. The cytotoxic effects of CPT, phenytoin and their combination were evaluated against various colorectal cancer cell lines (SW620, HT29 and HCT116) using sulforhodamine-B assay under normoxic and hypoxic conditions. In HT29, CPT alone and after combination treatment had IC50’s of 0.1235 µM and 0.0269 µM, respectively, under normoxic conditions; and 0.1352 µM and 0.0476 µM, respectively, under hypoxic conditions. In SW620, CPT alone and after combination treatment had IC50’s of 1.9861 µM and 0.0087 µM, respectively, under normoxic conditions; and 1.9549 µM and 0.0024 µM, respectively, under hypoxic conditions. In HCT116, CPT alone and after combination treatment had IC50’s of 0.163 µM and 0.0157 µM, respectively, under normoxic conditions; and 0.1013 µM and 0.0766 µM, respectively, under hypoxic conditions. Flow cytometric analysis after annexin-V/FITC staining showed that the combination treatment significantly induced total apoptosis in all cell lines under investigation. In both HT29 and SW620, the combination treatment significantly suppressed the autophagy compared to CPT treatment alone using acridine orange staining coupled with flowcytometry. Cell cycle analysis using DNA content flowcytometry after PI staining showed significant S-phase arrest in the combination treatment when compared to the control across all cell lines under investigation. This indicates that sub-molecular mechanisms of phenytoin induced chemomodulatory effect to CPT anticancer properties is oxygen tension dependent. Further investigation for the intratumoral metabolism of CPT under hypoxic as well as normoxic conditions and particularly those attributed to UGT-1A1 is currently undergoing. Citation Format: Dalia Al Saeedy, Reham K. Abuhijjleh, Ahmed Gouda, Sherif F. El-Khamisy, Ahmed M. Al-Abd. Modulating the polymorphic UGT1A1 gene to enhance camptothecin anti-colorectal effect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1049.

A hexanucleotide repeat expansion represents the most common genetic cause of\ud amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, though the\ud mechanisms by which the expansion cause neurodegeneration are poorly understood. We\ud report elevated levels of DNA/RNA hybrids (R-loops) and double-strand breaks (DSBs) in\ud rodent neurons, human cells, and in C9orf72-ALS patient spinal cord tissues.\ud Accumulation of endogenous DNA damage is concomitant with defective ATM-mediated\ud DNA repair signalling and accumulation of protein-linked DNA breaks. We further\ud reveal that defective ATM-mediated DNA repair is a consequence of p62 accumulation,\ud which impairs H2A ubiquitylation and perturbs ATM signalling. Adeno-associated virus-\ud mediated expression of C9orf72-related RNA and dipeptide repeats in the murine central\ud nervous system causes elevated DSBs, ATM defects, and triggers neurodegeneration.\ud These findings identify R-Loops, DSBs, and defective ATM-mediated repair as\ud pathological consequences of C9orf72 expansions, and suggest that C9orf72-linked\ud neurodegeneration is driven, at least in part, by genomic instability.

Eukaryotic topoisomerase 1 (TOP1) regulates DNA topology to ensure efficient DNA replication and transcription. TOP1 is also a major driver of endogenous genome instability, particularly when its catalytic intermediate—a covalent TOP1-DNA adduct known as a TOP1 cleavage complex (TOP1cc)—is stabilised. TOP1ccs are highly cytotoxic and a failure to resolve them underlies the pathology of neurological disorders but is also exploited in cancer therapy where TOP1ccs are the target of widely used frontline anti-cancer drugs. A critical enzyme for TOP1cc resolution is the tyrosyl-DNA phosphodiesterase (TDP1), which hydrolyses the bond that links a tyrosine in the active site of TOP1 to a 3’ phosphate group on a single-stranded (ss)DNA break. However, TDP1 can only process small peptide fragments from ssDNA ends, raising the question of how the ~90 kDa TOP1 protein is processed upstream of TDP1. Here we find that TEX264 fulfils this role by forming a complex with the p97 ATPase and the SPRTN metalloprotease. We show that TEX264 recognises both unmodified and SUMO1-modifed TOP1 and initiates TOP1cc repair by recruiting p97 and SPRTN. TEX264 localises to the nuclear periphery, associates with DNA replication forks, and counteracts TOP1ccs during DNA replication. Altogether, our study elucidates the existence of a specialised repair complex required for upstream proteolysis of TOP1ccs and their subsequent resolution., Eukaryotic topoisomerase 1 (TOP1) regulates DNA topology to ensure efficient DNA replication and transcription. Here, the authors reveal insights into the molecular resolution of topoisomerase 1-DNA adducts by TEX264, p97 and SPRTN.

Oxidative genome damage is an unavoidable consequence of cellular metabolism. It arises at gene regulatory elements by epigenetic demethylation during transcriptional activation

pVHL is a tumor suppressor. The lack of its function leads to various tumors, among which ccRCC (clear cell renal cell carcinoma) has the most serious outcome due to its resistance to chemotherapies and radiotherapies. Although HIF promotes the progression of ccRCC, the precise mechanism by which the loss of VHL leads to tumor initiation remains unclear. We exploited two zebrafish vhl mutants, vhl and vll, and Tg(phd3::GFP)i144 fish to identify crucial functions of Vhl in tumor initiation. Through the mutant analysis, we found that the role of pVHL in DNA repair is conserved in zebrafish Vll. Interestingly, we also discovered that Hif activation strongly suppressed genotoxic stress induced DNA repair defects and apoptosis in vll and brca2 mutants and in the embryos lacking ATM activity. These results suggest the potential of HIF as a clinical modulator that can protect cells from accumulating DNA damage and apoptosis which can lead to cancers and neurodegenerative disorders.

Salmonella Typhi activates the host DNA damage response through the typhoid toxin, facilitating typhoid symptoms and chronic infections. Here we reveal a non-canonical DNA damage response, which we call RING (response induced by a genotoxin), characterized by accumulation of phosphorylated histone H2AX (γH2AX) at the nuclear periphery. RING is the result of persistent DNA damage mediated by toxin nuclease activity and is characterized by hyperphosphorylation of RPA, a sensor of single-stranded DNA (ssDNA) and DNA replication stress. The toxin overloads the RPA pathway with ssDNA substrate, causing RPA exhaustion and senescence. Senescence is also induced by canonical γΗ2ΑΧ foci revealing distinct mechanisms. Senescence is transmitted to non-intoxicated bystander cells by an unidentified senescence-associated secreted factor that enhances Salmonella infections. Thus, our work uncovers a mechanism by which genotoxic Salmonella exhausts the RPA response by inducing ssDNA formation, driving host cell senescence and facilitating infection., Salmonella Typhi produces the typhoid toxin, which damages host cell DNA. Here, Ibler et al. show that the toxin induces a non-canonical DNA damage response mediated by the RPA pathway that drives host cell senescence and facilitates infection.

Development of ultra-sensitive, high specific and cost-effective nucleic acids (NAs) biosensors is critical for early diagnosis of cancer, genetic diseases and follows up response to treatment. Metal-organic frameworks (MOFs) as sensing materials underwent significant development in recent years due to their unique merits, such as structural diversity, tunable pore scale, large surface area, remarkable adsorption affinities, and good thermal stability. MOFs have shown potential contribution in nucleic acids biosensors research. Herein, a comprehensive overview on NAs biosensors state of the art based on MOFs has been discussed extensively, including different MOFs platforms sensing strategies (fluorescence, electrochemistry, electrochemiluminescence, and colorimetric techniques), their analytical performance and figures of merit in clinical diagnostics, with the future perspective in introducing MOFs in clinical laboratory diagnostics. Moreover, the different MOFs synthesis methods have been highlighted to serve as a guide for the researchers in selecting the appropriate platform that suits their research needs, and applications.

Ribonucleoside incorporation in genomic DNA poses a significant threat to genomic integrity. Here, we describe how cells tolerate this threat and discuss implications for cancer therapeutics., Ribonucleoside monophosphate (rNMP) incorporation in genomic DNA poses a significant threat to genomic integrity. In addition to repair, DNA damage tolerance mechanisms ensure replication progression upon encountering unrepaired lesions. One player in the tolerance mechanism is Rad5, which is an E3 ubiquitin ligase and helicase. Here, we report a new role for yeast Rad5 in tolerating rNMP incorporation, in the absence of the bona fide ribonucleotide excision repair pathway via RNase H2. This role of Rad5 is further highlighted after replication stress induced by hydroxyurea or by increasing rNMP genomic burden using a mutant DNA polymerase (Pol ε - Pol2-M644G). We further demonstrate the importance of the ATPase and ubiquitin ligase domains of Rad5 in rNMP tolerance. These findings suggest a similar role for the human Rad5 homologues helicase-like transcription factor (HLTF) and SNF2 Histone Linker PHD RING Helicase (SHPRH) in rNMP tolerance, which may impact the response of cancer cells to replication stress-inducing therapeutics.

Introduction: Breast cancer (BC) is a multifactorial disease, that is attributed to non-familial factors such as environmental or genetic factors that play a vital role in the development of the disease. BRCA1/2 mutations represent a high risk of breast cancer. The current study focused on exploring the relationship between the presence of BRCA1/2 mutations and some clinicopathological characteristics which might impact the pathogenesis of BC disease. Material and Methods: Genomic DNA samples were obtained from 19 fresh tissues using Gene JET Extraction Kit (Thermo Scientific/US, Canada), and 29 FFPE using QIAamp DNA FFPE Tissue Kit (Qiagen, Valencia, USA) obtained from pretreatment BC patients. Library preparation was performed using Devyser BRCA NGS kit (DEVYSER, Stockholm, Sweden), according to the manufacturer's instructions. The reagent kit V2, 500 Cycles PE, on the Illumina MiSeq System (Illumina, San Diego, CA, USA). The BRCA1 and BRCA2 genes reference were: NM_007300 and NM_000059, respectively. Variants were called using freebayes (1.1.0.46) and annotated using ANNOVAR(version2019Oct24). All samples were subjected for detection of Human Mammary Tumor Virus (HMTV) and Human Papillomavirus (HPV) DNAs using qualitative PCR assay. Result: The study identified 40 and 54 different BRCA1 and BRCA2 mutations, mostly in the form of frameshift and stop codon mutations. Regarding, BRCA1, 14 pathogenic mutations were detected, exon10 and exon 9 showed to be the most affected exons representing (c.C1612T (25%) and c.C1471T(22.9%), respectively. For BRCA2, only five pathogenic mutations were identified, exon 11 and exon 14 showed to be the most affected exons (cT4001A(6.25%) and c.7231delA(4.16%), respectively. Regarding relation between BRCA1/2 genes mutations and clinicopathological parameters, BRCA1 and BRCA2 carriers were younger than non-carriers though not significant (p=0.440). Regarding the tumor characteristics, BRCA1/2 carriers had large tumor size (p=0.091), high tumor grade compared to non-carriers but without significance (P=0.098). Micro-classifications positivity (60%) was also more frequently among BRCA1/2 carrier than non-carrier (p= 0.082). Regarding detection of HMTV and HPV, BRCA1/2 mutation carriers has a skew towards negative results (P= Conclusion: Our data suggest that BRCA1/2 mutations might contribute to the pathogenesis among both familial and non-familial Egyptian breast cancer patients, but we need more sample size to confirm the findings. It also identifies the most affected exons in preparation for establishing a diagnostic tool like HRM for genetic counseling, which will help when selecting treatment modalities for BC patients. STDF Acknowledgment: This project was supported financially by the Science and Technology Development Fund (STDF), Egypt, Grant No.22944 Citation Format: Samah A. Loutfy, Nasra F. Abdel Fattah, Ahmed B. Barakat, Omar R. Alfarouk, Tarek M. Hashem, Ahmed M. Osman, Shimaa A. Metwally, Maha A. Abo-Shadi, Amany M. Helal, Shaza A. Habib, Ahmed A. El Sherif, Abdel Wahab El Ghareeb, Mohamed M. Mouneer, Manar M. Moneer, Marwa A. Abdel-Wahed, Mona A. Salem, Asmaa M. M. M. Salama, Fatma S. Hafez, Sara H. Agwa, Hesham Elghazaly, Manal M. El-Mahdy, Mark J. Dunning, Sherif F. El-Khamisy. BRCA1 and BRCA2 mutations and its clinical relevance among egyptian breast cancer women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2512.

Purpose The objective of this study is to develop a facile tool for the absolute detection and quantification of nucleic acid transcripts, using a gold nanoparticle-based optical biosensor. Topoisomerase 1 (TOP1) and tyrosyl DNA phosphodiesterase 2 (TDP2) were among the nucleic acid transcripts of choice due to their role as genomic instability biomarkers and their implication in various cancers and neurologic disorders. This opens the door to develop a simple tool that can be used for diagnosing and monitoring treatment response for such diseases, overcoming the requirements for high cost, time, and complexity of the existing technologies for the absolute quantification of transcripts of interest. Materials and methods The TOP1 and TDP2 mRNA transcripts were first captured specifically using magnetic nanoparticles that were functionalized with TOP1- and TDP2-specific probes, respectively. The captured mRNA was then directly detected and quantified using the gold aggregating gold (GAG) assay, without the need for amplification as in existing technologies used for the quantification of transcripts. Results A linear correlation exists between the GAG assay and the qPCR for the quantification of the TOP1 and TDP2 mRNA transcripts (101–104 copies). The detection limit of the GAG assay in mRNA quantification was up to 10 copies per reaction. Wild-type and TDP2-deficient cell lines confirmed the assay specificity and reproducibility in distinguishing between different transcripts. Conclusion The GAG assay can be utilized as an inexpensive, rapid, simple, and sensitive tool for the absolute quantification of RNA for different applications, instead of the laborious, expensive, and sophisticated real-time PCR.

Stem cells serve as potential therapeutics due to their high proliferative capacity, low immunogenic reactivity and their differentiating capabilities. Several pre-clinical and early-stage clinical studies are carried out to treat genetic diseases, cancers and neurodegenerative disorders with promising preliminary results. However, there are still many challenges that scientists are trying to overcome such as the unclear expression profile of stem cells in vivo, the homing of stem cells to the site of injury and their potential immune-reactivity. Prospective research lies in gene editing of autologous stem cells in vitro and safe injection of these modified cells back into patients. Here, we review the clinical trials executed using stem cell therapy in an attempt to cure challenging diseases like cancer, Parkinson’s and Alzheimer’s diseases. Keywords: Cancer, Neurodegenerative disorders, Parkinson’s disease, Alzheimer’s disease, Stem cells

Colorimetric analysis is a method of determining the concentration of a chemical element or chemical compound in a solution with the aid of a color reagent. This poster explores the utilization of smartphones for colorimetric quantification of biological macromolecules. A low-cost optomechanical device and an Android application were designed to capture the image of a substance sample, and detect its concentration using the Saturation channel from the HSV color space. We report the device design and findings from preliminary experiments.

Ovarian cancer is the most aggressive female reproductive tract tumours. Taxane (paclitaxel; TX) is widely used for ovarian cancer treatment. However, ovarian cancers often acquire chemoresistance. MicroRNAs (miR) have been reported to mediate many tumours'chemoresistance. We investigated the role of miR-363 in the chemoresistance of the ovarian cancer cell line, KF, and its TX-resistant derivative (KF-TX) cells. QRT-PCR indicated that miR-363 was upregulated in KF-TX cells, and introduction of miR-363 into sensitive ovarian cancer cells confers TX-resistance and significantly inhibited the expression of the Hippo member, LATS2, as indicated by viability, clonogenic assay and expression analysis. Furthermore, we validated the role of LATS2 in TX-response by sh-based silencing, which also confers TX-resistance to the ovarian cancer cells. On the other hand, specific inhibitor against miR-363 restored the response to TX in the resistant cells. In addition, miR-363 was found to bind to the 3'-UTR of LATS2 mRNA, confirming that miR-363 directly targets LATS2 as indicated by dual luciferase assay. RT-PCR-based evaluation of miR-363 in a panel of human ovarian tumours revealed its upregulation in most of the tumour tissues identified as resistant while it was downregulated in most of the tissues identified as sensitive ones. Moreover, higher levels of miR-363 in human ovarian cancer specimens were significantly correlated with TX chemoresistance. Taken together, our study reveals the involvement of miR-363 in chemoresistance by targeting LATS2 in ovarian cancers, raising the possibility that combination therapy with a miR-363 inhibitor and TX may increase TX efficacy and reduce the chance of TX-resistance.

Carbon monoxide (CO)-releasing molecules (CORMs), mostly metal carbonyl compounds, are extensively used as experimental tools to deliver CO, a biological ‘gasotransmitter’, in mammalian systems. CORMs are also explored as potential novel antimicrobial drugs, effectively and rapidly killing bacteria in vitro and in animal models, but are reportedly benign towards mammalian cells. Ru-carbonyl CORMs, exemplified by CORM-3 (Ru(CO)3Cl(glycinate)), exhibit the most potent antimicrobial effects against Escherichia coli. We demonstrate that CORM-3 releases little CO in buffers and cell culture media and that the active antimicrobial agent is Ru(II), which binds tightly to thiols. Thus, thiols and amino acids in complex growth media – such as histidine, methionine and oxidised glutathione, but most pertinently cysteine and reduced glutathione (GSH) – protect both bacterial and mammalian cells against CORM-3 by binding and sequestering Ru(II). No other amino acids exert significant protective effects. NMR reveals that CORM-3 binds cysteine and GSH in a 1:1 stoichiometry with dissociation constants, Kd, of about 5 μM, while histidine, GSSG and methionine are bound less tightly, with Kd values ranging between 800 and 9000 μM. There is a direct positive correlation between protection and amino acid affinity for CORM-3. Intracellular targets of CORM-3 in both bacterial and mammalian cells are therefore expected to include GSH, free Cys, His and Met residues and any molecules that contain these surface-exposed amino acids. These results necessitate a major reappraisal of the biological effects of CORM-3 and related CORMs., Graphical abstract fx1, Highlights • Carbon monoxide-releasing molecules (CORMs) are used for experimental CO delivery. • CORM-3 is a potent antimicrobial, but is reportedly beneficial to mammalian cells. • We demonstrate CORM-3 releases little CO in buffers and cell culture media. • Redox-active Ru2+ is the biological agent, binding tightly to metabolites e.g. thiol. • These results necessitate a major reappraisal of the biological effects of CORMs.

The commonly used budding yeast strain W303 carries a mutant RAD5 gene (rad5-535), but numerous laboratories use a strain corrected for the mutation. This has resulted in different phenotypes of W303 cells in similar experiments. Here, we aim to raise awareness of the issue to ensure data reproducibility and interpretation.

Crocetin, the major carotenoid in saffron, exhibits potent anticancer effects. However, the antileukemic effects of crocetin are still unclear, especially in primary acute promyelocytic leukemia (APL) cells. In the current study, the potential antipromyelocytic leukemia activity of crocetin and the underlying molecular mechanisms were investigated. Crocetin (100 µM), like standard anti-APL drugs, all-trans retinoic acid (ATRA, 10 µM) and As2 O 3 (arsenic trioxide, 50 µM), significantly inhibited proliferation and induced apoptosis in primary APL cells, as well as NB4 and HL60 cells. The effect was associated with the decreased expressions of prosurvival genes Akt and BCL2, the multidrug resistance (MDR) proteins, ABCB1 and ABCC1 and the inhibition of tyrosyl-DNA phosphodiesterase 1 (TDP1), while the expressions of proapoptotic genes CASP3, CASP9, and BAX/BCL2 ratio were significantly increased. In contrast, crocetin at relatively low concentration (10 µM), like ATRA (1 µM) and As 2 O 3 (0.5 µM), induced differentiation of leukemic cells toward granulocytic pattern, and increased the number of differentiated cells expressing CD11b and CD14, while the number of the immature cells expressing CD34 or CD33 was decreased. Furthermore, crocetin suppressed the expression of clinical marker promyelocytic leukemia/retinoic acid receptor-α ( PML/RARα) in NB4 and primary APL cells, and reduced the expression of histone deacetylase 1 ( HDAC1) in all leukemic cells. The results suggested that crocetin can be considered as a candidate for future preclinical and clinical trials of complementary APL treatment.