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Trends in Cancer May 2024Gene fusions and rearrangements play a crucial role in tumor biology. They are rare events typically detected in KRAS wild-type (WT) pancreatic tumors. Their... (Review)
Review
Gene fusions and rearrangements play a crucial role in tumor biology. They are rare events typically detected in KRAS wild-type (WT) pancreatic tumors. Their identification can inform clinical management by enabling precision oncology, as fusions involving BRAF, FGFR2, RET, NTRK, NRG1, and ALK represent actionable targets in KRAS-WT cancers, and serve diagnostic purposes since fusions involving PRKACA/B represent the diagnostic hallmark of intraductal oncocytic papillary neoplasms (IOPNs). Although they are rare, the therapeutic and diagnostic importance of these genomic events should not be underestimated, highlighting the need for quality-ensured molecular diagnostics in the management of cancer. Herein we review the existing literature on the role of fusion genes in pancreatic tumors and their clinical potential as effective biomarkers and therapeutic targets.
Topics: Humans; Pancreatic Neoplasms; Oncogene Proteins, Fusion; Biomarkers, Tumor; Receptor, trkA; Proto-Oncogene Proteins c-ret; Proto-Oncogene Proteins B-raf; Receptor, Fibroblast Growth Factor, Type 2; Neuregulin-1; Anaplastic Lymphoma Kinase; Gene Fusion
PubMed: 38378317
DOI: 10.1016/j.trecan.2024.01.009 -
Scientific Reports Jul 2023Cleidocranial dysplasia (CCD) is a genetic disorder caused by mutations in the RUNX2 gene, affecting bone and teeth development. Previous studies focused on mutations in...
Cleidocranial dysplasia (CCD) is a genetic disorder caused by mutations in the RUNX2 gene, affecting bone and teeth development. Previous studies focused on mutations in the RUNX2 RHD domain, with limited investigation of mutations in the C-terminal domain. This study aimed to investigate the functional consequences of C-terminal mutations in RUNX2. Eight mutations were analyzed, and their effects on transactivation activity, protein expression, subcellular localization, and osteogenic potential were studied. Truncating mutations in the PST region and a missense mutation in the NMTS region resulted in increased transactivation activity, while missense mutations in the PST showed activity comparable to the control. Truncating mutations produced truncated proteins, while missense mutations produced normal-sized proteins. Mutant proteins were mislocalized, with six mutant proteins detected in both the nucleus and cytoplasm. CCD patient bone cells exhibited mislocalization of RUNX2, similar to the generated mutant. Mislocalization of RUNX2 and reduced expression of downstream genes were observed in MSCs from a CCD patient with the p.Ser247Valfs*3 mutation, leading to compromised osteogenic potential. This study provides insight into the functional consequences of C-terminal mutations in RUNX2, including reduced expression, mislocalization, and aberrant transactivation of downstream genes, contributing to the compromised osteogenic potential observed in CCD.
Topics: Humans; Core Binding Factor Alpha 1 Subunit; Mutation; Mutation, Missense; Cleidocranial Dysplasia
PubMed: 37500953
DOI: 10.1038/s41598-023-39293-1 -
Biophysical Journal Jun 2024Protein aggregates, formed from the assembly of aberrant, misfolded proteins, are a hallmark of neurodegenerative diseases. Disease-associated aggregates such as mutant...
Protein aggregates, formed from the assembly of aberrant, misfolded proteins, are a hallmark of neurodegenerative diseases. Disease-associated aggregates such as mutant Huntingtin polyQ inclusions, are typically enriched in p62/SQSTM1, an oligomeric protein that binds to and sequesters aberrant proteins. p62 has been suggested to sequester proteins through formation of liquid-like biomolecular condensates, but the physical mechanisms by which p62 condensates may regulate pathological protein aggregation remain unclear. Here, we use a light-inducible biomimetic condensate system to show that p62 condensates enhance coarsening of mutant polyQ aggregates through interface-mediated sequestration, which accelerates polyQ accumulation into larger aggregates. However, the resulting large aggregates accumulate polyubiquitinated proteins, which depletes free p62, ultimately suppressing further p62 condensation. This dynamic interplay between interface-mediated coarsening of solid aggregates and downstream consequences on the phase behavior of associated regulatory proteins could contribute to the onset and progression of protein aggregation diseases.
Topics: Peptides; Protein Aggregates; Humans; Biomolecular Condensates; Sequestosome-1 Protein
PubMed: 37837191
DOI: 10.1016/j.bpj.2023.10.009 -
Journal of Thoracic Disease Sep 2023The transformation of epidermal growth factor receptor ()-mutant lung adenocarcinoma (LUAD) into small cell lung cancer (SCLC) accounts for 3-14% of the resistance...
BACKGROUND
The transformation of epidermal growth factor receptor ()-mutant lung adenocarcinoma (LUAD) into small cell lung cancer (SCLC) accounts for 3-14% of the resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs). At present, there is no relevant research to explore the dynamic expression of -mutant proteins and genomic evolution in -mutant transformed SCLC/neuroendocrine carcinoma (NEC).
METHODS
Genetic analysis and protein level analysis by next-generation sequencing (NGS), Whole-exome sequencing (WES) and immunohistochemistry were performed to explore expression of -mutant proteins and genomic evolution in -mutant transformed SCLC. The research used three patient-derived organoids (PDOs) to explore the efficacy of combo [chemotherapy (chemo) plus TKI or bevacizumab] treatment. According to the subsequent treatment regimens after SCLC/NEC transformation, 35 patients were divided into chemo (n=21) and combo (n=14) groups.
RESULTS
L858R and E746-750 del protein expression by immunohistochemistry was 80.0% (4/5) and 100% (6/6), respectively (P=0.455) in initially-transformed tissues. Meanwhile, -mutant proteins were expressed in 85.7% (6/7) of dynamic rebiopsy tissues or effusion samples after the first transformation. Then, by the pathway enrichment analysis of tissue and plasma NGS, the EGFR-related pathways were still activated after SCLC/NEC transformation. Moreover, WES analysis revealed that transformed SCLC shared a common clonal origin from the baseline LUAD. The drug sensitivity of three PDOs demonstrated potent anti-cancer activity of EGFR-TKIs plus chemo, compared with chemo or TKI alone. There were significant differences in objective response rate (ORR) between the combo and chemo groups [42.9 % 4.8%, P=0.010, 95% confidence interval (CI): 1.5-145.2]. Furthermore, the median post-transformation progression-free survival (pPFS) was significantly prolonged in the combo group, with 5.4 (95% CI: 3.4-7.4) versus 3.5 (95% CI: 2.7-4.3, P=0.012) months.
CONCLUSIONS
19del or L858R-mutant proteins could be constantly expressed, and EGFR pathway still existed in -mutant transformed SCLC/NEC with a common clonal origin from the baseline LUAD. Taking together, these molecular characteristics potentially favored clinical efficacy in transformed SCLC/NEC treated with the combo regimen.
PubMed: 37868836
DOI: 10.21037/jtd-23-161 -
Current Opinion in Oncology Jul 2024There is an unmet need to improve outcomes for patients for Ewing sarcoma, a rare, aggressive sarcoma with a peak incidence in adolescents and young adults (AYA).... (Review)
Review
PURPOSE OF REVIEW
There is an unmet need to improve outcomes for patients for Ewing sarcoma, a rare, aggressive sarcoma with a peak incidence in adolescents and young adults (AYA). Current therapy at diagnosis involves multiagent chemotherapy and local therapy, but despite intensification of treatment, those with metastases at diagnosis and recurrent disease have poor outcomes.
RECENT FINDINGS
Improved understanding of Ewing sarcoma biology has identified novel targets with promising activity in Ewing sarcoma patients, including tyrosine kinase inhibitors that are now undergoing evaluation as combination and maintenance therapy. Other emerging therapies include those that target the EWSR1::FLI1 fusion oncoprotein, and act on DNA damage, cell cycle and apoptotic pathways. Immunotherapeutic approaches, particularly CAR-T-cell therapy directed at GD2, also hold promise. Recent collaborative clinical trials that have defined an international standard of care for patients with newly diagnosed Ewing sarcoma and novel platform studies with adaptive designs offer unique opportunities to investigate these therapies inclusive of all ages.
SUMMARY
Close international collaboration between clinicians and biologists will allow us to prioritize promising emerging therapies and develop biomarkers to facilitate their incorporation into standard of care and more rapidly translate into benefit for Ewing sarcoma patients.
Topics: Humans; Sarcoma, Ewing; Bone Neoplasms; Oncogene Proteins, Fusion; Molecular Targeted Therapy; Immunotherapy, Adoptive
PubMed: 38775200
DOI: 10.1097/CCO.0000000000001048 -
Proceedings of the National Academy of... Sep 2023Protein synthesis is a fundamental cellular process in neurons that is essential for synaptic plasticity and memory consolidation. Here, we describe our investigations...
Protein synthesis is a fundamental cellular process in neurons that is essential for synaptic plasticity and memory consolidation. Here, we describe our investigations of a neuron- and muscle-specific translation factor, ukaryotic longation actor (eEF1A2), which when mutated in patients results in autism, epilepsy, and intellectual disability. We characterize three patient mutations, G70S, E122K, and D252H, and demonstrate that all three mutations decrease de novo protein synthesis and elongation rates in HEK293 cells. In mouse cortical neurons, the mutations not only decrease de novo protein synthesis but also alter neuronal morphology, regardless of endogenous levels of eEF1A2, indicating that the mutations act via a toxic gain of function. We also show that eEF1A2 mutant proteins display increased tRNA binding and decreased actin-bundling activity, suggesting that these mutations disrupt neuronal function by decreasing tRNA availability and altering the actin cytoskeleton. More broadly, our findings are consistent with the idea that eEF1A2 acts as a bridge between translation and the actin cytoskeleton, which is essential for proper neuron development and function.
Topics: Animals; Humans; Mice; Actins; Autistic Disorder; Epilepsy; HEK293 Cells; Mutation; Peptide Elongation Factor 1
PubMed: 37695913
DOI: 10.1073/pnas.2307704120 -
Biology Oct 2023Lactose permease (LacY) from belongs to the major facilitator superfamily. It facilitates the co-transport of β-galactosides, including lactose, into cells by using a...
Lactose permease (LacY) from belongs to the major facilitator superfamily. It facilitates the co-transport of β-galactosides, including lactose, into cells by using a proton gradient towards the cell. We now show that LacY is capable of scrambling glycerophospholipids across a membrane. We found that purified LacY reconstituted into liposomes at various protein to lipid ratios catalyzed the rapid translocation of fluorescently labeled and radiolabeled glycerophospholipids across the proteoliposome membrane bilayer. The use of LacY mutant proteins unable to transport lactose revealed that glycerophospholipid scrambling was independent of H/lactose transport activity. Unexpectedly, in a LacY double mutant locked into an occluded conformation glycerophospholipid, scrambling activity was largely inhibited. The corresponding single mutants revealed the importance of amino acids G46 and G262 for glycerophospholipid scrambling of LacY.
PubMed: 37997967
DOI: 10.3390/biology12111367 -
Cancer Discovery Dec 2023PML nuclear bodies (NB) are disrupted in PML-RARA-driven acute promyelocytic leukemia (APL). Arsenic trioxide (ATO) cures 70% of patients with APL, driving PML-RARA...
UNLABELLED
PML nuclear bodies (NB) are disrupted in PML-RARA-driven acute promyelocytic leukemia (APL). Arsenic trioxide (ATO) cures 70% of patients with APL, driving PML-RARA degradation and NB reformation. In non-APL cells, arsenic binding onto PML also amplifies NB formation. Yet, the actual molecular mechanism(s) involved remain(s) elusive. Here, we establish that PML NBs display some features of liquid-liquid phase separation and that ATO induces a gel-like transition. PML B-box-2 structure reveals an alpha helix driving B2 trimerization and positioning a cysteine trio to form an ideal arsenic-binding pocket. Altering either of the latter impedes ATO-driven NB assembly, PML sumoylation, and PML-RARA degradation, mechanistically explaining clinical ATO resistance. This B2 trimer and the C213 trio create an oxidation-sensitive rheostat that controls PML NB assembly dynamics and downstream signaling in both basal state and during stress response. These findings identify the structural basis for arsenic targeting of PML that could pave the way to novel cancer drugs.
SIGNIFICANCE
Arsenic curative effects in APL rely on PML targeting. We report a PML B-box-2 structure that drives trimer assembly, positioning a cysteine trio to form an arsenic-binding pocket, which is disrupted in resistant patients. Identification of this ROS-sensitive triad controlling PML dynamics and functions could yield novel drugs. See related commentary by Salomoni, p. 2505. This article is featured in Selected Articles from This Issue, p. 2489.
Topics: Humans; Arsenic; Promyelocytic Leukemia Nuclear Bodies; Cysteine; Arsenicals; Oxides; Arsenic Trioxide; Leukemia, Promyelocytic, Acute; Oncogene Proteins; Oncogene Proteins, Fusion
PubMed: 37655965
DOI: 10.1158/2159-8290.CD-23-0453 -
Journal of Proteome Research Dec 2023Mutations in KRAS are common drivers of human cancers and are often those with the poorest overall prognosis for patients. A recently developed compound, MRTX1133, has...
Mutations in KRAS are common drivers of human cancers and are often those with the poorest overall prognosis for patients. A recently developed compound, MRTX1133, has shown promise in inhibiting the activity of KRAS mutant proteins, which is one of the main drivers of pancreatic cancer. To better understand the mechanism of action of this compound, I performed both proteomics and metabolomics on four KRAS mutant pancreatic cancer cell lines. To obtain increased granularity in the proteomic observations, single-cell proteomics was successfully performed on two of these lines. Following quality filtering, a total of 1498 single cells were analyzed. From these cells, 3140 total proteins were identified with approximately 953 proteins quantified per cell. At 48 h of treatment, two distinct populations of cells can be observed based on the level of effectiveness of the drug in decreasing the total abundance of the KRAS protein in each respective cell, with results that are effectively masked in the bulk cell analysis. All mass spectrometry data and processed results are publicly available at www.massive.ucsd.edu at accessions PXD039597, PXD039601, and PXD039600.
Topics: Humans; Proto-Oncogene Proteins p21(ras); Proteomics; Pancreatic Neoplasms; Mutation
PubMed: 37983312
DOI: 10.1021/acs.jproteome.3c00212 -
The Journal of Cell Biology Jul 2023The mechanisms that regulate the spatial sorting of nonmuscle myosins-2 (NM2) isoforms and couple them mechanically to the plasma membrane are unclear. Here we show that...
The mechanisms that regulate the spatial sorting of nonmuscle myosins-2 (NM2) isoforms and couple them mechanically to the plasma membrane are unclear. Here we show that the cytoplasmic junctional proteins cingulin (CGN) and paracingulin (CGNL1) interact directly with NM2s through their C-terminal coiled-coil sequences. CGN binds strongly to NM2B, and CGNL1 to NM2A and NM2B. Knockout (KO), exogenous expression, and rescue experiments with WT and mutant proteins show that the NM2-binding region of CGN is required for the junctional accumulation of NM2B, ZO-1, ZO-3, and phalloidin-labeled actin filaments, and for the maintenance of tight junction membrane tortuosity and apical membrane stiffness. CGNL1 expression promotes the junctional accumulation of both NM2A and NM2B and its KO results in myosin-dependent fragmentation of adherens junction complexes. These results reveal a mechanism for the junctional localization of NM2A and NM2B and indicate that, by binding to NM2s, CGN and CGNL1 mechanically couple the actomyosin cytoskeleton to junctional protein complexes to mechanoregulate the plasma membrane.
Topics: Adherens Junctions; Cell Membrane; Cytoskeletal Proteins; Cytoskeleton; Myosins; Tight Junctions
PubMed: 37204781
DOI: 10.1083/jcb.202208065