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Cell Chemical Biology Oct 2023Targeting transcription replication conflicts, a major source of endogenous DNA double-stranded breaks and genomic instability could have important anticancer...
Targeting transcription replication conflicts, a major source of endogenous DNA double-stranded breaks and genomic instability could have important anticancer therapeutic implications. Proliferating cell nuclear antigen (PCNA) is critical to DNA replication and repair processes. Through a rational drug design approach, we identified a small molecule PCNA inhibitor, AOH1996, which selectively kills cancer cells. AOH1996 enhances the interaction between PCNA and the largest subunit of RNA polymerase II, RPB1, and dissociates PCNA from actively transcribed chromatin regions, while inducing DNA double-stranded breaks in a transcription-dependent manner. Attenuation of RPB1 interaction with PCNA, by a point mutation in RPB1's PCNA-binding region, confers resistance to AOH1996. Orally administrable and metabolically stable, AOH1996 suppresses tumor growth as a monotherapy or as a combination treatment but causes no discernable side effects. Inhibitors of transcription replication conflict resolution may provide a new and unique therapeutic avenue for exploiting this cancer-selective vulnerability.
Topics: Humans; Proliferating Cell Nuclear Antigen; Chromatin; Protein Binding; Neoplasms; DNA; DNA Replication
PubMed: 37531956
DOI: 10.1016/j.chembiol.2023.07.001 -
Annual Review of Genomics and Human... Aug 2023Sickle cell disease (SCD) is a monogenic blood disease caused by a point mutation in the gene coding for β-globin. The abnormal hemoglobin [sickle hemoglobin (HbS)]... (Review)
Review
Sickle cell disease (SCD) is a monogenic blood disease caused by a point mutation in the gene coding for β-globin. The abnormal hemoglobin [sickle hemoglobin (HbS)] polymerizes under low-oxygen conditions and causes red blood cells to sickle. The clinical presentation varies from very severe (with acute pain, chronic pain, and early mortality) to normal (few complications and a normal life span). The variability of SCD might be due (in part) to various genetic modulators. First, we review the main genetic factors, polymorphisms, and modifier genes that influence the expression of globin or otherwise modulate the severity of SCD. Considering SCD as a complex, multifactorial disorder is important for the development of appropriate pharmacological and genetic treatments. Second, we review the characteristics, advantages, and disadvantages of the latest advances in gene therapy for SCD, from lentiviral-vector-based approaches to gene-editing strategies.
Topics: Humans; Anemia, Sickle Cell; Erythrocytes; Acute Pain; Chronic Pain; Hemoglobins, Abnormal
PubMed: 37624668
DOI: 10.1146/annurev-genom-120122-081037 -
Archives of Medical Research Jul 2023In humans, aging is characterized by a gradual decline of physical and psychological functions, with the concomitant onset of chronic-degenerative diseases, which... (Review)
Review
In humans, aging is characterized by a gradual decline of physical and psychological functions, with the concomitant onset of chronic-degenerative diseases, which ultimately lead to death. The study of Hutchinson-Gilford progeria syndrome (HGPS), a premature aging disorder that recapitulates several features of natural aging, has provided important insights into deciphering the aging process. The genetic origin of HGPS is a de novo point mutation in the LMNA gene that drives the synthesis of progerin, mutant version of lamin A. Progerin is aberrantly anchored to the nuclear envelope disrupting a plethora of molecular processes; nonetheless, how progerin exerts a cascade of deleterious alterations at the cellular and systemic levels is not fully understood. Over the past decade, the use of different cellular and animal models for HGPS has allowed the identification of the molecular mechanisms underlying HGPS, paving the way towards the development of therapeutic treatments against the disease. In this review, we present an updated overview of the biology of HGPS, including its clinical features, description of key cellular processes affected by progerin (nuclear morphology and function, nucleolar activity, mitochondrial function, protein nucleocytoplasmic trafficking and telomere homeostasis), as well as discussion of the therapeutic strategies under development.
Topics: Animals; Humans; Progeria; Aging; Mitochondria
PubMed: 37390702
DOI: 10.1016/j.arcmed.2023.06.002 -
Nature Communications Sep 2023Cas12a, a CRISPR-associated protein complex, has an inherent ability to cleave DNA substrates and is utilized in diagnostic tools to identify DNA molecules. We...
Cas12a, a CRISPR-associated protein complex, has an inherent ability to cleave DNA substrates and is utilized in diagnostic tools to identify DNA molecules. We demonstrate that multiple orthologs of Cas12a activate trans-cleavage in the presence of split activators. Specifically, the PAM-distal region of the crRNA recognizes RNA targets provided that the PAM-proximal seed region has a DNA target. Our method, Split Activator for Highly Accessible RNA Analysis (SAHARA), detects picomolar concentrations of RNA without sample amplification, reverse-transcription, or strand-displacement by simply supplying a short DNA sequence complementary to the seed region. Beyond RNA detection, SAHARA outperforms wild-type CRISPR-Cas12a in specificity towards point-mutations and can detect multiple RNA and DNA targets in pooled crRNA/Cas12a arrays via distinct PAM-proximal seed DNAs. In conclusion, SAHARA is a simple, yet powerful nucleic acid detection platform based on Cas12a that can be applied in a multiplexed fashion and potentially be expanded to other CRISPR-Cas enzymes.
Topics: RNA; CRISPR-Cas Systems; Point Mutation; RNA, Guide, CRISPR-Cas Systems; Recombination, Genetic
PubMed: 37669948
DOI: 10.1038/s41467-023-41006-1 -
JACC. CardioOncology Aug 2023•Mutations in the gene are observed in about 15% of NSCLC adenocarcinomas in the United States and are not associated with smoking. There are numerous mutations,... (Review)
Review
•Mutations in the gene are observed in about 15% of NSCLC adenocarcinomas in the United States and are not associated with smoking. There are numerous mutations, with the most common being exon 19 deletions and the point mutation L858R in exon 21.•Osimertinib, an oral TKI, is used as the initial therapy for metastatic NSCLC harboring exon 19 deletion and exon 21 L858R mutation. Common side effects include acneiform rash, diarrhea, and paronychia. Osimertinib has also been associated with cardiomyopathy (∼1.4%-2.4%) and prolongation of the QT interval (2.7%).•In our experience, osimertinib-induced cardiomyopathy can be managed with the cessation of osimertinib and the initiation of guideline-directed therapy. Given that osimertinib is often the best available therapy, rechallenging with osimertinib often favors benefit over risk. Safe rechallenge with osimertinib is demonstrated in this case.
PubMed: 37614580
DOI: 10.1016/j.jaccao.2023.04.005 -
Cancer Research Oct 2023RAS proteins are GTPases that regulate a wide range of cellular processes. RAS activity is dependent on its nucleotide-binding status, which is modulated by guanine...
UNLABELLED
RAS proteins are GTPases that regulate a wide range of cellular processes. RAS activity is dependent on its nucleotide-binding status, which is modulated by guanine nucleotide exchange factors (GEF) and GTPase-activating proteins (GAP). KRAS can be acetylated at lysine 104 (K104), and an acetylation-mimetic mutation of K104 to glutamine (K104Q) attenuates the in vitro-transforming capacity of oncogenic KRAS by interrupting GEF-induced nucleotide exchange. To assess the effect of this mutation in vivo, we used CRISPR-Cas9 to generate mouse models carrying the K104Q point mutation in wild-type and conditional KrasLSL-G12D alleles. Homozygous animals for K104Q were viable, fertile, and arose at the expected Mendelian frequency, indicating that K104Q is not a complete loss-of-function mutation. Consistent with our previous findings from in vitro studies, however, the oncogenic activity of KRASG12D was significantly attenuated by mutation at K104. Biochemical and structural analysis indicated that the G12D and K104Q mutations cooperate to suppress GEF-mediated nucleotide exchange, explaining the preferential effect of K104Q on oncogenic KRAS. Furthermore, K104 functioned in an allosteric network with M72, R73, and G75 on the α2 helix of the switch-II region. Intriguingly, point mutation of glycine 75 to alanine (G75A) also showed a strong negative regulatory effect on KRASG12D. These data demonstrate that lysine at position 104 is critical for the full oncogenic activity of mutant KRAS and suggest that modulating the sites in its allosteric network may provide a unique therapeutic approach in cancers expressing mutant KRAS.
SIGNIFICANCE
An allosteric network formed by interaction between lysine 104 and residues in the switch-II domain is required for KRAS oncogenicity, which could be exploited for developing inhibitors of the activated oncoprotein.
Topics: Animals; Mice; Allosteric Regulation; Guanine Nucleotide Exchange Factors; Lysine; Mutation; Nucleotides; Proto-Oncogene Proteins p21(ras); ras Proteins
PubMed: 37556505
DOI: 10.1158/0008-5472.CAN-22-3210 -
Journal of Advanced Research Apr 2024Tumor-associated calcium signal transducer 2 (Trop2) has been used as a transport gate for cytotoxic agents into cells in antibody-drug conjugate designs because of its...
INTRODUCTION
Tumor-associated calcium signal transducer 2 (Trop2) has been used as a transport gate for cytotoxic agents into cells in antibody-drug conjugate designs because of its expression in a wide range of solid tumors. However, the specific role of Trop2 itself in breast cancer progression remains unclear and small molecules targeting Trop2 have not yet been reported.
OBJECTIVES
To screen small molecules targeting Trop2, and to reveal its pharmacological effects and the molecular mechanisms of action.
METHODS
Small molecule targeting Trop2 was identified by cell membrane chromatography, and validated by cellular thermal shift assay and point mutation analyses. We investigated the pharmacological effects of Trop2 inhibitor using RNA-seq, human foreskin fibroblast (HFF)-derived extracellular matrix (ECM), Matrigel drop invasion assays, colony-forming assay, xenograft tumor model, 4T1 orthotopic metastasis model and 4T1 experimental metastasis model. The molecular mechanism was determined using immunoprecipitation, mass spectrometry, immunofluorescence, immunohistochemistry and Western blotting.
RESULTS
Here we identified Bruceine D (BD) as the inhibitor of Trop2, and demonstrated anti-metastasis effects of BD in breast cancer. Notably, Lys307 and Glu310 residues of Trop2 acted as critical sites for BD binding. Mechanistically, BD suppressed Trop2-induced cancer metastasis by blocking the formation of Trop2/β-catenin positive loop, in which the Trop2/β-catenin complex prevented β-catenin from being degraded via the ubiquitin-proteosome pathway. Destabilized β-catenin caused by BD reduced nucleus translocation, leading to the reduction of transcription of Trop2, the reversal of epithelial-mesenchymal transition (EMT) process, and the inhibition of ECM remodeling, further inhibiting cancer metastasis. Additionally, the inhibitory effects of BD on lung metastatic colonization and the beneficial effects of BD on prolongation of survival were validated in 4T1 experimental metastasis model.
CONCLUSIONS
These results support the tumor-promoting role of Trop2 in breast cancer by stabilizing β-catenin in Trop2/β-catenin positive loop, and suggest Bruceine D as a promising candidate for Trop2 inhibition.
Topics: Animals; Humans; Female; Breast Neoplasms; Signal Transduction; Cell Line, Tumor; beta Catenin; Feedback; Disease Models, Animal; Quassins
PubMed: 37271476
DOI: 10.1016/j.jare.2023.05.012 -
Tidsskrift For Den Norske Laegeforening... Mar 2024Anemia in children is common and finding the underlying cause is often uncomplicated. However, in some cases, the underlying diagnosis is rare and difficult to diagnose.
BACKGROUND
Anemia in children is common and finding the underlying cause is often uncomplicated. However, in some cases, the underlying diagnosis is rare and difficult to diagnose.
CASE PRESENTATION
A toddler presented with severe anemia with normal red cell indices and a low reticulocyte count. The remaining hematological parameters were normal, bar a slight thrombocytosis. At this point a diagnosis of transient erythroblastopenia of childhood (TEC) was made. The child continued to have slight anemia with intermittent macrocytosis and reticulocytopenia throughout childhood. Growth and development was normal, and there were no signs of congenital abnormalities in the heart or kidneys nor any craniofacial or phalangeal defects. Repeated bone marrow examinations showed no significant abnormal findings. As a teenager the patient was diagnosed with Diamond-Blackfan anemia through an exome-based gene panel which revealed a mutation in the RPL11 gene.
INTERPRETATION
Congenital bone marrow failure syndromes do not always present in the classical way, leading to a delayed diagnosis. The increasing availability of different gene panels for patients with persistent abnormal hematological laboratory parameters offers the possibility of a more accurate diagnostic pathway, which is important for adequate follow-up and genetic counselling.
Topics: Adolescent; Humans; Anemia; Anemia, Diamond-Blackfan; Anemia, Hemolytic, Congenital; Mutation
PubMed: 38506013
DOI: 10.4045/tidsskr.23.0415 -
Cancer Diagnosis & Prognosis 2023Salivary gland carcinomas belong to the head and neck carcinoma super category of malignancies. They are characterized by histopathological diversity and comprise a... (Review)
Review
Salivary gland carcinomas belong to the head and neck carcinoma super category of malignancies. They are characterized by histopathological diversity and comprise a variety of entities and subtypes. Mucoepidermoid, adenoid cystic and salivary duct carcinomas represent the most prominent malignancies. Concerning their corresponding genetic background, a broad spectrum of gene and chromosomal imbalances has been detected. Point mutations and deletions, amplifications and translocations, combined or not with chromosomal aneuploidy/polysomy/monosomy, create a landscape of specific genetic signatures that affect the biological behavior of these tumors and modify response rates to potential targeted therapeutic strategies. In the current molecular review, we focused on the categorization and description of the most important mutational signatures in salivary gland carcinomas.
PubMed: 37405215
DOI: 10.21873/cdp.10233