Recent COVID-19 vaccines unleashed the potential of mRNA-based therapeutics. A common bottleneck across mRNA-based therapeutic approaches is the rapid design of mRNA sequences that are translationally efficient, long-lived and non-immunogenic. Currently, an accessible software tool to aid in the design of such high-quality mRNA is lacking.
View Article and Find Full Text PDFBiodegraders are targeted protein degradation constructs composed of mini-proteins/peptides linked to E3 ligase receptors. We gained deeper insights into their utility by studying Con1-SPOP, a biodegrader against proliferating cell nuclear antigen (PCNA), an oncology target. Con1-SPOP proved pharmacologically superior to its stoichiometric (non-degrading) inhibitor equivalent (Con1-SPOPmut) as it had more potent anti-proliferative effects and uniquely induced DNA damage, cell apoptosis, and necrosis.
View Article and Find Full Text PDFImmune checkpoint blockade (ICB) leads to durable and complete tumour regression in some patients but in others gives temporary, partial or no response. Accordingly, significant efforts are underway to identify tumour-intrinsic mechanisms underlying ICB resistance. Results from a published CRISPR screen in a mouse model suggested that targeting STUB1, an E3 ligase involved in protein homeostasis, may overcome ICB resistance but the molecular basis of this effect remains unclear.
View Article and Find Full Text PDFMacrocyclic peptides have the potential to address intracellular protein-protein interactions (PPIs) of high value therapeutic targets that have proven largely intractable to small molecules. Here, we report broadly applicable lessons for applying this modality to intracellular targets and specifically for advancing chemical matter to address KRAS, a protein that represents the most common oncogene in human lung, colorectal and pancreatic cancers yet is one of the most challenging targets in human disease. Specifically, we focused on KRpep-2d, an arginine-rich KRAS-binding peptide with a disulfide-mediated macrocyclic linkage and a protease-sensitive backbone.
View Article and Find Full Text PDFMutations to RAS proteins (H-, N-, and K-RAS) are among the most common oncogenic drivers, and tumors harboring these lesions are some of the most difficult to treat. Although covalent small molecules against KRAS have shown promising efficacy against lung cancers, traditional barriers remain for drugging the more prevalent KRAS and KRAS mutants. Targeted degradation has emerged as an attractive alternative approach, but for KRAS, identification of the required high-affinity ligands continues to be a challenge.
View Article and Find Full Text PDFTargeted degradation approaches such as proteolysis targeting chimeras (PROTACs) offer new ways to address disease through tackling challenging targets and with greater potency, efficacy, and specificity over traditional approaches. However, identification of high-affinity ligands to serve as PROTAC starting points remains challenging. As a complementary approach, we describe a class of molecules termed biological PROTACs (bioPROTACs)-engineered intracellular proteins consisting of a target-binding domain directly fused to an E3 ubiquitin ligase.
View Article and Find Full Text PDFStapled α-helical peptides represent an emerging superclass of macrocyclic molecules with drug-like properties, including high-affinity target binding, protease resistance, and membrane permeability. As a model system for probing the chemical space available for optimizing these properties, we focused on dual Mdm2/MdmX antagonist stapled peptides related to the p53 N-terminus. Specifically, we first generated a library of ATSP-7041 (Chang et al.
View Article and Find Full Text PDFMacrocyclic α-helical peptides have emerged as a compelling new therapeutic modality to tackle targets confined to the intracellular compartment. Within the scope of hydrocarbon-stapling there has been significant progress to date, including the first stapled α-helical peptide to enter into clinical trials. The principal design concept of stapled α-helical peptides is to mimic a cognate (protein) ligand relative to binding its target via an α-helical interface.
View Article and Find Full Text PDFIn five separate families, we identified nine individuals affected by a previously unidentified syndrome characterized by growth retardation, spine malformation, facial dysmorphisms, and developmental delays. Using homozygosity mapping, array CGH, and exome sequencing, we uncovered bi-allelic loss-of-function CDK10 mutations segregating with this disease. CDK10 is a protein kinase that partners with cyclin M to phosphorylate substrates such as ETS2 and PKN2 in order to modulate cellular growth.
View Article and Find Full Text PDFSox2 is known to be important for neuron formation, but the precise mechanism through which it activates a neurogenic program and how this differs from its well-established function in self-renewal of stem cells remain elusive. In this study, we identified a highly conserved cyclin-dependent kinase (Cdk) phosphorylation site on serine 39 (S39) in Sox2. In neural stem cells (NSCs), phosphorylation of S39 enhances the ability of Sox2 to negatively regulate neuronal differentiation, while loss of phosphorylation is necessary for chromatin retention of a truncated form of Sox2 generated during neurogenesis.
View Article and Find Full Text PDFp53 tumor suppressor maintains genomic stability, typically acting through cell-cycle arrest, senescence, and apoptosis. We discovered a function of p53 in preventing conflicts between transcription and replication, independent of its canonical roles. p53 deficiency sensitizes cells to Topoisomerase (Topo) II inhibitors, resulting in DNA damage arising spontaneously during replication.
View Article and Find Full Text PDFTrisomy 21 (T21), Down Syndrome (DS) is the most common genetic cause of dementia and intellectual disability. Modeling DS is beginning to yield pharmaceutical therapeutic interventions for amelioration of intellectual disability, which are currently being tested in clinical trials. DS is also a unique genetic system for investigation of pathological and protective mechanisms for accelerated ageing, neurodegeneration, dementia, cancer, and other important common diseases.
View Article and Find Full Text PDFMouse knockouts of Cdk2 and Cdk4 are individually viable whereas the double knockouts are embryonic lethal due to heart defects, and this precludes the investigation of their overlapping roles in definitive hematopoiesis. Here we use a conditional knockout mouse model to investigate the effect of combined loss of Cdk2 and Cdk4 in hematopoietic cells. Cdk2(fl/fl)Cdk4(-/-)vavCre mice are viable but displayed a significant increase in erythrocyte size.
View Article and Find Full Text PDFCyclin-dependent kinases (Cdks) are serine/threonine kinases and their catalytic activities are modulated by interactions with cyclins and Cdk inhibitors (CKIs). Close cooperation between this trio is necessary for ensuring orderly progression through the cell cycle. In addition to their well-established function in cell cycle control, it is becoming increasingly apparent that mammalian Cdks, cyclins and CKIs play indispensable roles in processes such as transcription, epigenetic regulation, metabolism, stem cell self-renewal, neuronal functions and spermatogenesis.
View Article and Find Full Text PDFSuccessful completion of the cell cycle relies on the precise activation and inactivation of cyclin-dependent kinases (Cdks) whose activity is mainly regulated by binding to cyclins. Recently, a new family of Cdk regulators termed Speedy/RINGO has been discovered, which can bind and activate Cdks but shares no apparent amino acid sequence homology with cyclins. All Speedy proteins share a conserved domain of approximately 140 amino acids called "Speedy Box", which is essential for Cdk binding.
View Article and Find Full Text PDFDuring neurogenesis, cell cycle regulators play a pivotal role in ensuring proper proliferation, cell cycle exit, and differentiation of neural precursors. However, the precise role of cyclin-dependent kinases (Cdks) in these processes is not well understood. We generated Cdk2 and Cdk4 double knockout (DKO) mice and found a striking ablation of the intermediate zone and cortical plate in mouse embryonic brain.
View Article and Find Full Text PDFAsthma is a chronic inflammatory disease characterized by airway inflammation, mucus hypersecretion and airway hyperresponsiveness. Mechanisms underlying the pathogenesis of asthma are not fully understood. In recent years, there are mounting evidences demonstrating that mammalian chitinases may play a key role in mediating the T-helper 2 cell-driven inflammatory response that is commonly associated with asthma.
View Article and Find Full Text PDFWe investigated p53-dependent gene expression in nitric oxide (NO)-induced apoptosis of two tumor cell types. Seventy-seven putative p53-regulated genes were screened for NO-mediated expression changes. Twenty-four genes were up-regulated and three genes were down-regulated significantly by NO in human neuroblastoma cells.
View Article and Find Full Text PDFAm J Respir Crit Care Med
September 2007
Rationale: Persistent activation of nuclear factor-kappaB has been associated with the development of asthma. Glycogen synthase kinase-3beta is known to regulate the activity of nuclear factor-kappaB.
Objectives: We hypothesized that inhibition of glycogen synthase kinase-3beta may have anti-inflammatory effects in allergic asthma.
Clin Exp Pharmacol Physiol
August 2007
1. An antisense oligonucleotide (ASO) is a short strand of deoxyribonucleotide analogue that hybridizes with the complementary mRNA in a sequence-specific manner via Watson-Crick base pairing. Formation of the ASO-mRNA heteroduplex either triggers RNase H activity, leading to mRNA degradation, induces translational arrest by steric hindrance of ribosomal activity, interferes with mRNA maturation by inhibiting splicing or destabilizes pre-mRNA in the nucleus, resulting in downregulation of target protein expression.
View Article and Find Full Text PDF