Biology subjects

Jin, Q.

Publications and source records attributed to Jin, Q..

At least 19 recordsLinked to original sources

bioRxiv2026

Multimodal allostery in a single-domain protein

Allosteric communication between distant sites in proteins is central to biological regulation and underlies the efficacy of many drugs. Allostery allows proteins to function as molecular switches, with their activities controlled by ligand binding, covalent modifications, and mutations outside their active sites. Allosteric maps have been constructed for several proteins, but these all quantify regulation of a single site in each protein. How the allosteric maps of different sites compare is unclear. Here, we address this question by charting complete allosteric maps for two structurally distant binding sites in the oncoprotein KRAS. Unexpectedly, these maps reveal three different forms of allosteric control, that we term coupled, anti-coupled and independent allostery. Allostery in this small protein is therefore complex and multimodal. The co-existence of multiple allosteric networks in a single-domain protein has important conceptual implications and, if widespread, may allow the development of new classes of therapeutics that not only modulate targets but also tune their functional outputs.

biochemistry↗

bioRxiv2026

Lamin A/C depletion from myofibers and satellite cells in mice reveals selective muscle pathology

Mutations in the laminA/C gene (LMNA), which encodes the nuclear lamina proteins lamin A and lamin C (lamin A/C), have been linked to different human diseases affecting different tissues. Most LMNA mutations cause cardiomyopathy and muscular dystrophy, such as autosomal dominant Emery-Dreifuss muscular dystrophy. Recent studies to understand striated muscle laminopathies have taken advantage of Lmna conditional knockout mice to examine the effects of lamin A/C depletion in cardiomyocytes and cardiac fibroblasts. However, the role of lamin A/C in skeletal muscle has largely been uncharacterized using conditional knockout mice. We used different mouse lines to deplete lamin A/C from specific cell types in striated muscle. Lamin A/C depletion from fetal myofibers and cardiomyocytes led to no observable phenotype in the skeletal muscles despite leading to dramatic heart dilation and early lethality. Depletion of lamin A/C from both skeletal myofibers and satellite cells was lethal, with the most dramatic myopathic abnormalities observed in the intrinsic muscles of the tongue. The presence of lamin A/C in skeletal muscle satellite cells prevented the development of lethal myopathy when the proteins were deleted only from differentiated myofibers. Overall, our results provide a foundation for understanding the roles of lamin A/C in muscle maintenance and development, including the variable skeletal muscle involvement and much more invariant cardiomyopathy in patients with LMNA mutations.

pathology↗

bioRxiv2026

Distal conformational steering by N-terminal pyroglutamylation enables subtype-selective GPCR activation across Aplysia PRXamide and human Neuromedin U signaling

Post-translational modifications (PTMs) diversify neuropeptide function, yet how minimal modifications encode receptor specificity without direct contact remains a fundamental challenge in chemical biology. Pyroglutamylation (pQ), a prevalent N-terminal PTM in bioactive peptides, introduces a rigid cyclic constraint, yet its mechanistic role in receptor signaling is unclear. Here, using two newly identified endogenous Aplysia PRXamide receptors (ApPRXa R1 and ApPRXa-R2) as a model system, we find that the same ligand, MMG2-pDPb (pQPPLPRYamide), produces opposite functional outcomes: pQ suppresses ApPRXa-R1 activation while enhancing ApPRXa-R2 activation. In vitro and in silico analyses demonstrate that the N-terminal pQ/Q remains solvent-exposed and does not directly contact receptor residues. Instead, pQ reshapes the ligand conformational ensemble and redistributes interaction networks across shared receptor contact sites. Strikingly, this molecular logic extends to mammalian Neuromedin U (NmU) receptors, as canine NmU (pQFLFRPRNamide) similarly biases subtype preference of human NmU receptors. Both static and dynamic analyses further reveal that receptor pocket mechanics determine the direction of this modulation: a loose and permissive pocket better accommodates the rigid pQ-constrained ligand, whereas a more compact pocket favors the non-pyroglutamylated ligand. These findings define a "PTM distal steering" mechanism that bridges "lock-key" and "induced-fit" paradigms and establish a general principle by which a minimal, non-contacting modification encodes receptor preference through ligand conformational biasing and pocket-dependent permissiveness, providing a chemical framework for optimizing stable, conformation-biased neuropeptide analogs.

biochemistry↗

bioRxiv2026

Maximizing the productivity of co-transcriptional in vitro transcription

mRNA therapeutics have demonstrated transformative potential in infectious disease, oncology and genetic disorders. Parallel to the rapid clinical advancement of mRNA therapies, research into in vitro transcription (IVT), the pivotal process of mRNA manufacturing, has intensified significantly. However, the majority of these studies omitted cap analog, an essential substrate for co-transcriptional capped IVT (co-IVT), likely to simplify experimental systems. Nevertheless, co-IVT remains the dominant industrial standard for the production of mRNA therapeutics. Here, we report an optimized co-IVT process that achieves a yield of more than 26 g/L while maintaining capping efficiency of over 99.5%, and achieving a 30-fold reduction in double-stranded RNA (dsRNA), the most critical process-related impurity. These performance gains substantially improve mRNA production efficiency and enhance mRNA quality, thereby accelerating the transition to commercial-scale manufacturing of mRNA therapeutics. Moreover, the performance was attained using either of two mechanistically distinct engineered T7 RNA polymerase (RNAP) mutants. Both mutants enabled robust mRNA synthesis under process conditions that have not been previously reported. These observations provide mechanistic insights into IVT and advance our fundamental understanding of this critical bio-manufacturing step.

bioengineering↗

bioRxiv2026

De novo design of ligand binding and sensing with a physics based generative approach

The de novo design of ligand-binding proteins has tremendous potential to revolutionize biosensor technology, yet converting these designs into functional sensors remains a major challenge due to the need for ligand-induced conformational changes or modulation of protein-protein interactions. Here, we introduce a physics-based generative approach for the de novo creation of proteins that bind small molecules and metal ions. Our method achieves customizable ligand-binding pocket formation in parallel with simulated protein folding, allowing for precise architectural control of the protein-ligand complex and facilitating the development of biosensors based on either ligand-triggered protein reassociation via split-protein reassembly or ligand-induced protein folding. We demonstrate the versatility of our computational method through successful designs targeting five small molecules, including the very small neurotransmitters serotonin and dopamine, and two metal ions. Biophysical characterization confirmed correct ligand binding, and crystal structures closely matched computational models. We demonstrated the biosensor engineering potential of these designs by constructing serotonin and dopamine sensors using a split protein strategy and explored several approaches to enhance sensor activity. Additionally, we developed a zinc sensor through a zinc-induced protein folding mechanism. Overall, our physics-based generative approach provides a robust framework for the de novo design of ligand-binding proteins, opening new avenues for the development of ligand-responsive biosensors.

bioinformatics↗

bioRxiv2026

TCR signal strength determines Treg instability and discrimination of self versus non-self antigens

Regulatory T cells (Tregs) expressing autoreactive T-cell receptors (TCRs) maintain immune self-tolerance, yet their fate upon antigen encounter remains unclear. Although selected in the thymus for high-affinity self-recognition, the cross-reactive nature of the TCR repertoire allows some Tregs to also recognize foreign antigens with high affinity. Here, we identify cross-reactive destabilization, a process in which high-affinity recognition of foreign antigens erodes Treg stability and redirects lineage fate. Using a thymic-derived Treg (tTreg) TCR capable of recognizing both self and foreign antigens distinct from the self-ligand that mediated its thymic selection, we show that stimulation with high-affinity non-self agonists induces Foxp3 loss and conversion into effector-like ex-Tregs, whereas self-antigen stimulation preserves lineage stability. Treg instability also increases with age and correlates with activation, suggesting that cumulative foreign-antigen exposure drives this process. These findings reveal a signal-strength-dependent model in which strong TCR engagement induces cross-reactive destabilization to balance immune responsiveness and self-tolerance. One Sentence SummaryForeign antigen-driven destabilization of Treg cells balances immunity and tolerance

immunology↗

bioRxiv2026

Sexual size dimorphism increases with body size at the intraspecific level in Drosophila melanogaster

Sexual size dimorphism (SSD), the difference in body size between males and females, typically conforms to Renschs rule across species: SSD increases with body size when males are larger but decreases when females are larger. Although this macroevolutionary pattern has been extensively documented, intraspecific analyses remain rare, yet they are essential for understanding the proximate mechanisms underlying the origin and maintenance of sexual dimorphism. In particular, it remains unclear whether within-species variation in SSD is driven primarily by sex-specific differences in growth rate or in development time. Here, we addressed this question by examining SSD scaling in inbred lines of Drosophila melanogaster from the well-established Drosophila melanogaster Genetic Reference Panel (DGRP) reared under two thermal environments (25 {degrees}C and 28 {degrees}C). Females were consistently larger than males, resulting in pronounced female-biased SSD across different lines of this model insect. Moreover, SSD increased with overall body size, representing a reversal of Renschs rule at the intraspecific level. This scaling pattern was largely explained by higher female growth rates rather than sexual differences in development time. Elevated temperature reduced SSD by decreasing female growth rate while slightly enhancing that of males. Together, our results demonstrate that Renschs rule does not universally apply at intraspecific level and underscore the critical role of growth rate and environmental sensitivity in shaping SSD at the intraspecific level.

ecology↗

bioRxiv2026

Blank Spectrum Correction as a Robust Solution to Artifacts in Quantitative X-ray Fluorescence Mapping

X-ray fluorescence microscopy (XFM) continues to develop as a powerful quantitative technique for high resolution, label-free, elemental mapping of biological, environmental, and material samples. Methods for rigorously fitting spectra, increasing throughput, accounting for background signals, and deconvoluting overlapping emission lines continue to evolve. We show here that quantitative fits of XFM data obtained after removing a baseline, calculated by connecting peak edges, can be unexpectedly dependent upon acquisition dwell-time and spectral aggregation leading to differences in apparent elemental content. Using mouse preimplantation embryos and ovarian follicles as model samples, we demonstrate how these variables influence quantitative comparisons between samples. We find that subtracting an empirically measured blank spectrum instead of a baseline provides quantitative XFM elemental mapping results that are independent of dwell time and spectral aggregation dependencies.

biophysics↗

bioRxiv2025

A Paracrine-to-Autocrine Shunt of GREM1 Fuels Colorectal Cancer Metastasis via ACVR1C

Tumor cells typically rely on paracrine stromal signals to guide malignant behaviors, but whether they acquire signaling autonomy to support metastasis remains unclear. We elucidate this in colorectal cancer (CRC) by uncovering a paracrine-to-autocrine shunt of Gremlin1 (GREM1), a canonical stromal-secreted antagonist of bone morphogenetic proteins (BMPs). We demonstrate that while GREM1 remains restricted to stromal cells in earlier-stage (I-III) CRC, its ectopic expression in tumor epithelium increases markedly in stage IV. Mechanistically, we identify ACVR1C as a novel, high-affinity epithelial receptor for GREM1. Their interaction activates SMAD2/3 signaling, which upregulates SNAI1 and GREM1, establishing a feedback loop that amplifies epithelial-mesenchymal transition (EMT). Disrupting this loop impairs CRC metastasis in vivo. Clinically, epithelial GREM1 or ACVR1C expression predicts metastasis and poor survival. These findings define a paradigm in which tumor cells hijack stromal GREM1 to establish a GREM1-ACVR1C autocrine loop that sustains EMT and metastasis, marking a shift toward signaling autonomy and revealing a targetable vulnerability in advanced CRC.

cancer biology↗

bioRxiv2025

An All-In-One Software Solution for Automated Processing of LA-ICP-TOF-MS datasets

LA-ICP-TOF-MS provides rapid, high resolution elemental analysis of biological and non-biological samples. However, accurate real-time data analysis frequently requires the user to account for several instrumental and experimental variables that can change during data acquisition. AutoSpect is a novel software tool designed to automate the processing and fitting of LA-ICP-TOF-MS data, addressing key challenges such as time-dependent spectral drift, instrument sensitivity drift calibration inaccuracies, and peak deconvolution, enabling researchers to rapidly and accurately process complex datasets. The tool is optimized to be robustly applicable across scientific fields (e.g., geochemistry, biology, and materials science), providing a streamlined solution for end users seeking to maximize the potential of LA-ICP-TOF-MS for high-resolution elemental mapping and isotopic analysis. Significance to JAASAnalysis of fast transient signals using laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS) has become mainstream for elemental mapping. Advancements in LA-ICP-TOF-MS technology continue to accelerate the collective understanding of the role inorganic chemistry plays in dynamic processes. To ensure accurate quantitative results, the vast amount of complex spectral data generated requires elegant solutions to perform a variety of functions including data partitioning, peak fitting, drift correction, mass-to-charge calibration, peak profiling, and spectral fitting. AutoSpect is an all-in-one software solution that provides high level automation with a user-friendly graphical interface to perform complex data analyses for ICP-TOF-MS datasets.

scientific communication and education↗

bioRxiv2025

Multifunctional bending magnet beamline with a capillary optic for X-ray fluorescence studies of metals in tissue sections

Scanning fluorescence X-ray microscopy lets one non-destructively and quantitatively map the distribution of most biologically-important metals in cells and tissues. For studies on large-scale tissues and organs, a spatial resolution of several micrometers is often sufficient; in this case, bending magnets at synchrotron light sources provide abundant X-ray flux. We describe here the use of bending magnet beamline 8-BM-B at the Advanced Photon Source (APS) with two distinct microscopy stations: a pre-existing one with Kirkpatrick-Baez (KB) mirror optics for slightly higher throughput and the ability to accommodate samples tens of centimeters across, and a new prototype station with an axially-symmetric, single-bounce, capillary optic with slightly less flux, but slightly higher fluence (which affects achievable resolution at low metal concentration) and higher spatial resolution. The KB station provides{delta} res = 10.5 {micro}m spatial resolution at a per-pixel exposure time of tdwell = 100 ms and a fluence per time of 5.8x 107 photons /({micro}m2 {middle dot}s), while the prototype capillary station provides{delta} res = 6.3 {micro}m at tdwell = 50 ms and a fluence per time of 6.1x 107 photons ({micro}m2 {middle dot}s). We used image power spectral density to estimate the achieved spatial resolution{delta} res from individually acquired images, with{delta} res depending-on the optic, the fluorescence signal strength of the sample being imaged, and the method used to process raw fluorescence spectral data.

biophysics↗

bioRxiv2024

Functional fingerprinting for the developing brain using deep metric learning: an ABCD study

Brain fingerprinting is a promising approach for characterizing the uniqueness of individual brain functioning using functional magnetic resonance imaging (fMRI) data. Here, we propose a novel deep learning framework, the metric-BoIT, for brain fingerprinting and demonstrate its effectiveness in capturing individual variability among early adolescents undergoing dramatic brain changes. Utilizing resting-state fMRI data from the Adolescent Brain Cognitive Development (ABCD) dataset, we identified brain functional fingerprints that achieved remarkable individual identification accuracy, reaching 97.6% within a single session and maintaining 86.6% accuracy over a four-year developmental period. Annotation analysis revealed that higher-order association regions, particularly those within the default-mode network, contributed most significantly to these distinctive brain fingerprints (t = 5.618, p < 0.001). Moreover, these brain fingerprints were relevant to cognitive functions, as evidenced by significant correlations with fluid intelligence (F = 1.282, p = 0.027) and crystallized intelligence (F = 1.405, p < 0.001). The extracted brain fingerprints were additionally associated with genetics, showing that individuals with strong genomic relationships exhibited more similar brain fingerprint patterns (t = -12.330, p < 0.001). Together, our study not only presents an innovative approach to brain functional fingerprinting but also provides valuable insights into the individual variability underlying adolescent neurodevelopment.

neuroscience↗

bioRxiv2024

Epigenetic remodeling and 3D chromatin reorganization governed by NKX2-1 drive neuroendocrine prostate cancer

A significant number of castration-resistant prostate cancer (CRPC) evolve into a neuroendocrine (NE) subtype termed NEPC, leading to resistance to androgen receptor (AR) pathway inhibitors and poor clinical outcomes. Through Hi-C analyses of a panel of patient-derived xenograft tumors, here we report drastically different 3D chromatin architectures between NEPC and CRPC samples. Such chromatin re-organization was faithfully recapitulated in vitro on isogenic cells undergoing NE transformation (NET). Mechanistically, neural transcription factor (TF) NKX2-1 is selectively and highly expressed in NEPC tumors and is indispensable for NET across various models. NKX2-1 preferentially binds to gene promoters, but it interacts with chromatin-pioneering factors such as FOXA2 at enhancer elements through chromatin looping, further strengthening FOXA2 binding at NE enhancers. Conversely, FOXA2 mediates regional DNA demethylation, attributing to NE enhancer priming and inducing NKX2-1 expression, forming a feed-forward loop. Single-cell multiome analyses of isogenic cells over time-course NET cells identify individual cells amid luminal-to-NE transformation, exhibiting intermediate epigenetic and transcriptome states. Lastly, NKX2-1/FOXA2 interacts with, and recruits CBP/p300 proteins to activate NE enhancers, and pharmacological inhibitors of CBP/p300 effectively blunted NE gene expression and abolished NEPC tumor growth. Thus, our study reports a hierarchical network of TFs governed by NKX2-1 in regulating the 2D and 3D chromatin re-organization during NET and uncovers a promising therapeutic approach to eradicate NEPC.

cancer biology↗

bioRxiv2024

SARS-CoV-2 JN.1 reveals attenuated pathogenicity and airborne transmission

JN.1 is a subvariant of SARS-CoV-2 Omicron BA.2.86 lineage that was predominant worldwide in early 2024, of which the in vivo characteristics are largely unknown. Our results demonstrated that the replication of JN.1 was more efficient than that of the parental BA.2 in Vero cells, which demonstrated low dependence on TMPRSS2. Compared to Omicron variants BA.2 and XBB EG.5.1, JN.1 replicated less efficiently in hACE2 mouse lungs of which the intranasal infection was not lethal to hACE2 mice and led to weaker immune dysregulation. On a more sensitive, aged hACE2 hamster model, JN.1 led to a lower mortality rate and no weight loss, corresponding well with the low preference in lower airways. Lower amounts of viruses in nasal washes and exhaled aerosols were detected in JN.1 infected wildtype hamsters than EG.5.1, and consistently, JN.1 also exhibited largely reduced airborne transmission. Moreover, the poor transmission was also clearly demonstrated even by using hamsters expressing hACE2 receptors in the whole airway. Thus both pathogenicity and airborne transmission of JN.1 were demonstrated to be largely attenuated. ImportanceCurrently, SARS-CoV-2 JN.1 and its subvariants have fully replaced the previous dominant XBB lineage around the world. Although the strong immune evasion of JN.1 has been distinctly revealed, its in vivo pathogenicity and airborne transmission remained unclear. By using multiple Omicron-sensitive rodent models, our findings demonstrated that the pathogenicity of JN.1 was largely attenuated. The weak airborne transmission of JN.1 in wildtype and hACE2 hamsters was consistent with the reported relative lower transmissibility in human, and the using of airway-expressing hACE2 hamsters ulteriorly eliminates the potential bias in viral transmission studies induced by receptor divergence between animal models and human. These findings uncover the in vivo virological characteristics of SARS-CoV-2 novel lineage, providing insights for communicable disease control.

microbiology↗

bioRxiv2024

Peri-centrosomal localization of small interfering RNAs in C. elegans

The centrosome is the microtubule-organizing center and a crucial part of cell division. Centrosomal RNAs (cnRNAs) have been reported to enable precise spatiotemporal control of gene expression during cell division in many species. Whether and how cnRNAs exist in C. elegans are unclear. Here, using the nuclear RNAi Argonaute protein NRDE-3 as a reporter, we observed potential peri-centrosome localized small interfering (si)RNAs in C. elegans. NRDE-3 was previously shown to associate with pre-mRNAs and pre-rRNAs via a process involving the presence of complementary siRNAs. We generated a GFP-NRDE-3 knock-in transgene through CRISPR/Cas9 technology and observed that NRDE-3 formed peri-centrosomal foci neighboring the tubulin protein TBB-2, other centriole proteins and pericentriolar material (PCM) components in C. elegans embryos. The peri-centrosomal accumulation of NRDE-3 depends on RNA-dependent RNA polymerase (RdRP)-synthesized 22G siRNAs and the PAZ domain of NRDE-3, which is essential for siRNA binding. Mutation of eri-1, ergo-1, or drh-3 significantly increased the percentage of pericentrosome-enriched NRDE-3. At the metaphase of the cell cycle, NRDE-3 was enriched in both the peri-centrosomal region and the spindle. Moreover, the integrity of centriole proteins and pericentriolar material (PCM) components is also required for the peri-centrosomal accumulation of NRDE-3. Therefore, we concluded that siRNAs could accumulate in the peri-centrosomal region in C. elegans and suggested that the peri-centrosomal region may also be a platform for RNAi-mediated gene regulation.

genetics↗

bioRxiv2024

Increased pathogenicity and transmission of SARS-CoV-2 Omicron XBB.1.9 sublineage, including HK.3 and EG.5.1

With the SARS-CoV-2 Omicron XBB.1.9 sublineage circulating worldwide, two XBB.1.9 variants, EG.5.1 and HK.3 spread rapidly and became dominant from middle 2023. However, the spike features, pathogenicity, and transmissibility of HK.3 are largely unknown. Here, we performed multiscale investigations to reveal the virological features of XBB.1.9 subvariants, especially the newly emerging HK.3. HK.3 revealed high replication efficiency in vitro. The HK.3 spike exhibited enhanced processing, although its infectivity, fusogenicity, and hACE2 binding affinity were comparable to those of the EG.5 and XBB.1 spikes. All XBB.1.9.1, EG.5.1 and HK.3 strains demonstrated efficient transmission in hamsters, although XBB.1.9.1 exhibited stronger fitness in the upper airways. HK.3 and EG.5.1 exhibited greater pathogenicity than XBB.1.9.1 and BA.2 in H11-K18-hACE2 hamsters. Our studies provide insight into the newly emerging pathogens HK.3 and EG.5.1. ImportanceIn animal models, the ongoing attenuated pathogenicity and poor transmission of Omicron subvariants seems to reach a consensus. However, our results revealed that Omicron XBB.1.9 subvariants, including one of the key variants of interest, EG.5 with its another key subvariant HK.3, universally exhibited both increased pathogenicity and highly transmission. This study reemphasized the importance of surveillance in characteristics of epidemic Omicron subvariants.

microbiology↗

bioRxiv2024

Virological characteristics of SARS-CoV-2 Omicron BA.5.2.48

With the prevalence of sequentially-emerged sublineages including BA.1, BA.2 and BA.5, SARS-CoV-2 Omicron infection has transformed into a regional epidemic disease. As a sublineage of BA.5, the BA.5.2.48 outbreak and evolved into multi-subvariants in China without clearly established virological characteristics, especially the pathogenicity. Though reduced airborne transmission and pathogenicity of former Omicron sublineages have been revealed in animal models, the virological characteristics of BA.5.2.48 was unidentified. Here, we evaluated the in vitro and in vivo virological characteristics of two isolates of the prevalent BA.5.2.48 subvariant, DY.2 and DY.1.1 (a subvariant of DY.1). DY.2 replicates more efficiently than DY.1.1 in HelahACE2+ cells and Calu-3 cells. The A570S mutation (of DY.1) in a normal BA.5 spike protein (DY.2) leads to a 20% improvement in the hACE2 binding affinity, which is slightly reduced by a further K147E mutation (of DY.1.1). Compared to the normal BA.5 spike, the double-mutated protein demonstrates efficient cleavage and reduced fusogenicity. BA.5.2.48 demonstrated enhanced airborne transmission capacity in hamsters than BA.2. The pathogenicity of BA.5.2.48 is greater than BA.2, as revealed in K18-hACE2 rodents. Under immune selection pressure, DY.1.1 shows stronger fitness than DY.2 in hamster turbinates. Thus the outbreaking prevalent BA.5.2.48 multisubvariants exhibites divergent virological features. ImportanceOmicron continues to circulate and evolves novel sublineages with indistinguishable pathogenicity and transmission. Therefore humanized Omicron-sensitive animal models must be applied to evaluate the virological characteritics and antiviral therapeutics. By using multiple models including the Omicron-lethal H11-K18-hACE2 rodents, BA.5.2.48 revealed higher pathogenicity in the novel H11-K18-hACE2 rodent models than the previously epidemic BA.2, and thus the models are more adapted to Omicron studies. Moreover, the regional outbreaking of BA.5.2.48 promotes the multidirectional evolution of its subvariants, gaining either enhanced pathogenicity or a fitness in upper airways which is associated with higher transmission, highlighting the importance of surveillance and virological studies on regionally endemic sublineages which represents the short-run evolutionary direction of Omicron.

microbiology↗

bioRxiv2023

Breakage fusion bridge cycles drive high oncogene copy number, but not intratumoral genetic heterogeneity or rapid cancer genome change

Oncogene amplification is a major driver of cancer pathogenesis. Breakage fusion bridge (BFB) cycles, like extrachromosomal DNA (ecDNA), can lead to high copy numbers of oncogenes, but their impact on intratumoral heterogeneity, treatment response, and patient survival are not well understood due to difficulty in detecting them by DNA sequencing. We describe a novel algorithm that detects and reconstructs BFB amplifications using optical genome maps (OGMs), called OM2BFB. OM2BFB showed high precision (>93%) and recall (92%) in detecting BFB amplifications in cancer cell lines, PDX models and primary tumors. OM-based comparisons demonstrated that short-read BFB detection using our AmpliconSuite (AS) toolkit also achieved high precision, albeit with reduced sensitivity. We detected 371 BFB events using whole genome sequences from 2,557 primary tumors and cancer lines. BFB amplifications were preferentially found in cervical, head and neck, lung, and esophageal cancers, but rarely in brain cancers. BFB amplified genes show lower variance of gene expression, with fewer options for regulatory rewiring relative to ecDNA amplified genes. BFB positive (BFB (+)) tumors showed reduced heterogeneity of amplicon structures, and delayed onset of resistance, relative to ecDNA(+) tumors. EcDNA and BFB amplifications represent contrasting mechanisms to increase the copy numbers of oncogene with markedly different characteristics that suggest different routes for intervention.

cancer biology↗