bioRxiv Science⌕ Search

Biology subjects

Shi, Y.

Publications and source records attributed to Shi, Y..

At least 343 records · Page 19Linked to original sources

Deeplearning based MHC epitope prediction for cancer neoantigen discovery

Neoantigens are important for cancer immunotherapies or cancer vaccine development, but identification of neoantigens is challenging. The high binding affinity between the mutated peptide and MHC (major histocompatibility complex) molecules of the patients is a necessary factor for a somatic mutation on the tumor genome to form a neoantigen. MHC epitope prediction tools can be used for the identification of neoantigens. This research investigates MHC epitope prediction by utilizing Tri-peptide similarity as features for the XGBoost classifier. This model was tested on experimentally validated cancer neoantigen peptides.

bioinformatics↗

Cryo-EM structure of the Inner Ring from Xenopus laevis Nuclear Pore Complex

Nuclear pore complex (NPC) mediates nucleocytoplasmic shuttling. Here we present single-particle cryo-electron microscopy (cryo-EM) structure of the inner ring (IR) subunit from Xenopus laevis NPC at an average resolution of 4.4 [A]. The symmetric IR subunit comprises a cytoplasmic half and a nuclear half. A homo-dimer of Nup205 resides at the center of the IR subunit, flanked by two molecules of Nup188. Four molecules of Nup93 each places an extended helix into the axial groove of Nup205 or Nup188, together constituting the central scaffold. The channel nucleoporin heterotrimer (CNT) of Nup54/58/62 is anchored on the central scaffold. Six Nup155 molecules interact with the central scaffold and together with the NDC1-ALADIN hetero-dimers anchor the IR subunit to the nuclear envelope and to outer rings. The scarce inter-subunit contacts may allow sufficient latitude in conformation and diameter of the IR. Our structure of vertebrate IR reveals key insights that are functionally important.

biophysics↗

Scaling between DNA and cell size governs bacterial growth homeostasis and resource allocation

Bacteria maintain a stable cell size and a certain DNA content through proliferation as described by classic growth laws. How cells behave when this inherent scaling is broken, however, has rarely been interrogated. Here we engineered Escherichia coli cells with extremely low DNA contents using a tunable synthetic tool CRISPRori that temporarily inhibited chromosome replication initiation. A detailed mechanistic model coupling DNA replication, cell growth, and division revealed a fundamental DNA-centric growth law, which was validated by two observations. First, lineage dynamics were robust to large CRISPRori perturbations with division cycles rapidly restoring through a timer mechanism rather than the adder rule. Second, cellular growth transitioned into a linear regime at low DNA-cytoplasm ratios. Experiments and theory showed that in this regime, cellular resource was redirected to plasmid-borne gene expression. Together with the ability of CRISPRori to bi-directionally modulate plasmid copy numbers, these findings suggest a novel strategy for bio-production enhancement.

systems biology↗

Age-dependent formation of TMEM106B amyloid filaments in human brain

Many age-dependent neurodegenerative diseases, like Alzheimers and Parkinsons, are characterised by abundant inclusions of amyloid filaments. Filamentous inclusions of the proteins tau, amyloid-{beta} (A{beta}), -synuclein and TDP-43 are the most common. Here, we used electron cryo-microscopy (cryo-EM) structure determination to show that residues 120-254 of the lysosomal type II transmembrane protein 106B (TMEM106B) also form amyloid filaments in the human brain. We solved cryo-EM structures of TMEM106B filaments from the brains of 22 individuals with neurodegenerative conditions, including sporadic and inherited tauopathies, A{beta}-amyloidoses, synucleinopathies and TDP-43opathies, as well as from the brains of two neurologically normal individuals. We observed three different TMEM106B folds, with no clear relationship between folds and diseases. The presence of TMEM106B filaments correlated with that of a 29 kDa sarkosyl-insoluble fragment of the protein on Western blots. The presence of TMEM106B filaments in the brains of older, but not younger, neurologically normal individuals indicates that they form in an age-dependent manner.

neuroscience↗

Base editing in bovine embryos reveals a species-specific role of SOX2 in regulation of pluripotency

The emergence of the first three lineages during development are orchestrated by a network of transcription factors, which are best characterized in mice. However, the role and regulation of these factors are not completely conserved in other mammals, including human and cattle. Here, we establish a gene inactivation system by introducing premature codon with cytosine base editor in bovine embryos with a robust efficiency. Of interest, SOX2 is universally localized in early blastocysts but gradually restricted into the inner cell mass in cattle. SOX2 knockout results in a failure of the establishment of pluripotency. Indeed, OCT4 level is significantly reduced and NANOG was barely detectable. Furthermore, the formation of primitive endoderm is compromised with few SOX17 positive cells. Single embryo RNA-seq reveals a dysregulation of 2074 genes, among which 90% are up-regulated in SOX2-null blastocysts. Intriguingly, more than a dozen lineage-specific genes, including OCT4 and NANOG, are down-regulated. Moreover, SOX2 expression is sustained in the trophectoderm in absence of CDX2 in bovine late blastocysts. Overall, we propose that SOX2 is dispensable for OCT4 and NANOG expression and disappearance of SOX2 in the trophectoderm depends on CDX2 in cattle, which are all in sharp contrast with results in mice. SignificanceThe first and second cell fate decisions of a new life are important for subsequent embryonic and plancental development. These events are finely controlled by a network of transcriptional factors, which are extensively characterized in mice. Species-specific roles of these proteins are emerging in mammals. Here, we develop a gene loss-of-function system by using cytosine base editors in bovine embryos. We find that expression pattern, functional roles, and regulation of SOX2 are all different between mouse and bovine embryos. Remarkbly, SOX2 is required for OCT4 and NANOG, two well established pluripoteny genes. Furthermore, CDX2 is required to shut down SOX2 in the trophectoderm. Given similar expression pattern of SOX2 between human and bovine blastocysts, bovine embryos represents a putative model to investigate human pluripotency regulation in vivo.

developmental biology↗

Intact Drosophila Whole Brain Cellular Quantitation reveals Sexual Dimorphism

Establishing with precision the quantity and identity of the cell types of the brain is a prerequisite for a detailed compendium of gene and protein expression in the central nervous system. Currently however, strict quantitation of cell numbers has been achieved only for the nervous system of C.elegans. Here we describe the development of a synergistic pipeline of molecular genetic, imaging, and computational technologies designed to allow high-throughput, precise quantitation with cellular resolution of reporters of gene expression in intact whole tissues with complex cellular constitutions such as the brain. We have deployed the approach to determine with exactitude the number of functional neurons and glia in the entire intact larval Drosophila central nervous system (CNS), revealing fewer neurons and more glial cells than previously predicted. We also discover an unexpected divergence between the sexes at this juvenile developmental stage, with the female CNS having significantly more neurons than that of males. Topological analysis of our data establishes that this sexual dimorphism extends to deeper features of CNS organisation. We additionally extended our analysis to quantitate the expression of voltage-gated potassium channel family genes throughout the CNS and uncover substantial differences in abundance. Our methodology enables robust and accurate quantification of the number and positioning of cells within intact organs, facilitating sophisticated analysis of cellular identity, diversity, and gene expression characteristics.

neuroscience↗

Comprehensive Structure and Functional Adaptations of the Yeast Nuclear Pore Complex

Nuclear Pore Complexes (NPCs) mediate the nucleocytoplasmic transport of macromolecules. Here we provide a structure of the yeast NPC in which the inner ring is resolved by cryo-EM at - helical resolution to show how flexible connectors tie together different structural and functional layers in the spoke. These connectors are targets for phosphorylation and regulated disassembly in cells with an open mitosis. Moreover, some nucleoporin pairs and karyopherins have similar interaction motifs, which suggests an evolutionary and mechanistic link between assembly and transport. We also provide evidence for three major NPC variants that foreshadow functional specializations at the nuclear periphery. Cryo-electron tomography extended these studies to provide a comprehensive model of the in situ NPC with a radially-expanded inner ring. Our model reveals novel features of the central transporter and nuclear basket, suggests a role for the lumenal ring in restricting dilation and highlights the structural plasticity required for transport by the NPC.

biophysics↗

Eicosanoids in the pancreatic tumor microenvironment: a multicellular, multifaceted progression

Eicosanoids, oxidized fatty acids that serve as cell-signaling molecules, have been broadly implicated in tumorigenesis. To identify eicosanoids relevant to pancreatic tumorigenesis, we profiled normal pancreas and pancreatic ductal adenocarcinoma (PDAC) in mouse models and patient samples using mass spectrometry. We interrogated RNA sequencing datasets for eicosanoid synthase or receptor expression. Findings were confirmed by immunostaining. In murine models, we identified elevated levels of PGD2, prostacyclin, and thromboxanes in neoplasia while PGE2, 12-HHTre, HETEs, and HDoHEs are elevated specifically in tumors. Analysis of scRNA-seq datasets suggests that PGE2 and prostacyclins are derived from fibroblasts, PGD2 and thromboxanes from myeloid cells, and PGD2 and 5-HETE from tuft cells. In patient samples, we identified a transition from PGD2 to PGE2-producing enzymes in the epithelium during the transition to PDAC, fibroblast/tumor expression of PTGIS, and myeloid/tumor cell expression of TBXAS1. Altogether, our analyses identify key changes in eicosanoid species during pancreatic tumorigenesis and the cell types responsible for their synthesis.

cancer biology↗

An increase in surface hydrophobicity mediates chaperone activity in N-chlorinated proteins

Under physiological conditions, Escherichia coli RidA is an enamine/imine deaminase, which promotes the release of ammonia from reactive enamine/imine intermediates. However, when modified by hypochlorous acid (HOCl), as produced by the host defense, RidAHOCl turns into a potent chaperone-like holdase that can effectively protect the proteome of E. coli during oxidative stress. We previously reported that the activation of RidAs chaperone-like function coincides with the addition of at least seven and up to ten chlorine atoms. These atoms are reversibly added to basic amino acids in RidAHOCl and removal by reducing agents leads to inactivation. Nevertheless, it remains unclear, which residues in particular need to be chlorinated for activation. Here, we employ a combination of LC-MS/MS analysis, a chemo-proteomic approach, and a mutagenesis study to identify residues responsible for RidAs chaperone-like function. Through LC-MS/MS of digested RidAHOCl, we obtained direct evidence of the chlorination of one arginine residue (and, coincidentally, two tyrosine residues), while other N- chlorinated residues could not be detected, presumably due to the instability of the modification and its potential interference with a proteolytic digest. Therefore, we established a chemoproteomic approach using 5-(dimethylamino) naphthalene-1-sulfinic acid (DANSO2H) as a probe to label N-chlorinated lysines. Using this probe, we were able to detect the N-chlorination of six additional lysine residues. Moreover, using a mutagenesis study to genetically probe the role of single arginine and lysine residues, we found that the removal of arginines R105 and R128 leads to a substantial reduction of RidAHOCls chaperone activity. These results, together with structural analysis, confirm that the chaperone activity of RidA is concomitant with the loss of positive charges on the protein surface, leading to an increased overall protein hydrophobicity. Molecular modelling of RidAHOCl and the rational design of a RidA variant that shows chaperone activity even in the absence of HOCl further supports our hypothesis. Our data provide a molecular mechanism for HOCl-mediated chaperone activity found in RidA and a growing number of other HOCl-activated chaperones.

biochemistry↗

Mutual Regulation between PFKP and VEGF Promotes Glioblastoma Tumor Growth

Glioblastoma (GBM) is highly vascular malignant brain tumor that overexpresses vascular endothelial growth factor (VEGF) and phosphofructokinase 1 platelet isoform (PFKP), which catalyzes a rate-limiting reaction in glycolysis. However, it remains unknown whether PFKP and VEGF are reciprocally regulated during GBM tumor growth. Here, we show that PFKP promotes EGFR activation-induced VEGF expression in HIF-1-dependent and -independent manners in GBM cells. Importantly, we demonstrate that EGFR-phosphorylated PFKP Y64 has critical roles in the AKT/SP1-mediated transcriptional expression of HIF-1 and in the AKT-mediated {beta}-catenin S552 phosphorylation, to fully enhance VEGF transcription and subsequent blood vessel formation and brain tumor growth. The levels of PFKP Y64 phosphorylation in human GBM specimens positively correlate with HIF-1 expression, {beta}-catenin S552 phosphorylation, and VEGF expression. Conversely, VEGF upregulates PFKP expression in a PFKP S386 phosphorylation-dependent manner, leading to increased PFK enzyme activity, aerobic glycolysis, and proliferation in GBM cells. These findings highlight a novel mechanism underlying the mutual regulation that occurs between PFKP and VEGF for promoting GBM tumor growth and provide the therapeutic potential of targeting the PFKP/VEGF regulatory loop for GBM patients.

cancer biology↗

Diet-derived metabolites and mucus link the gut microbiome to fever after cytotoxic cancer treatment

Not all cancer patients with severe neutropenia develop fever, and the fecal microbiome may play a role. In neutropenic hematopoietic cell transplant patients (n=119), 63 (53%) developed a subsequent fever and had increased fecal Akkermansia muciniphila, a mucus-degrading bacteria (p=0.006, corrected for multiple comparisons). In mouse models, two therapies, irradiation and melphalan, similarly expanded A. muciniphila. Dietary restriction of unirradiated mice also expanded A. muciniphila and thinned the colonic mucus layer. Azithromycin treatment depleted A. muciniphila and preserved colonic mucus. Dietary restriction raised colonic luminal pH and reduced acetate, propionate, and butyrate. Culturing A. muciniphila with lower pH and increased propionate prevented utilization of mucin. Treating irradiated mice with azithromycin or propionate preserved the mucus layer, lessened hypothermia, and reduced inflammatory cytokines in the colon. These results suggest that diet, metabolites and colonic mucus link the microbiome to neutropenic fever, and could guide future microbiome-based preventive strategies.

microbiology↗

The histone deacetylase activity of HDAC1/2 is required to safeguard zygotic genome activation in mice and cattle

The genome is transcriptionally inert at fertilization and must be activated through a remarkable developmental process called zygotic genome activation (ZGA). The gene expression pattern formed over the course of ZGA is required for establishing totipotency in early embryos and subsequent development. Substantial epigenetic reprogramming contributes significantly to the pronounced change in gene expression during ZGA, however the mechanism has yet to be resolved. Here, we find histone deacetylase 1 and 2 (HDAC1/2) are critical histone modifiers that regulate ZGA through the histone deacetylase activity. Notably, we show that H3K27ac level declines dramatically during ZGA with a dynamic change in its genome-wide distribution. In mouse embryos, ectopic expression of HDAC1/2 dominant negative mutant leads to a failure of H3K27ac removal and a developmental arrest at 2-cell stage. RNA-seq results reveal a remarkable transcriptomic change with 6565 differentially expressed genes identified. Further analysis shows 64% of down-regulated genes are ZGA genes and 49% of up-regulated genes are developmental genes. Low input ChIP-seq analysis exhibits an increase and decrease of H3K27ac enrichment at the promoter region of up- and down-regulated genes, respectively. Moreover, HDAC1 mutants prohibited removal of broad H3K4me3 domain via impeding the expression of Kdm5s during ZGA. Importantly, the developmental block can be greatly overcome through injection of Kdm5b mRNA and expression of the majority of dysregulated genes partially corrected. Similar functional significance of HDAC1/2 in ZGA is conserved in bovine embryos. Together, we propose that HDAC1/2 is indispensable for mouse and bovine ZGA via creating correct transcriptional repressive and active states.

developmental biology↗

Llamanade: an open-source computational pipeline for robust nanobody humanization

Nanobodies (Nbs) have recently emerged as a promising class of antibody fragments for biomedical and therapeutic applications. Despite having marked physicochemical properties, Nbs are derived from camelids and may require "humanization" to improve translational potentials for clinical trials. Here we have systematically analyzed the sequence and structural properties of Nbs based on NGS (next-generation sequencing) databases and high-resolution structures. Our analysis reveals substantial framework diversities and underscores the key differences between Nbs and human Immunoglobulin G (IgG) antibodies. We identified conserved residues that may contribute to enhanced solubility, structural stability, and antigen-binding, providing insights into Nb humanization. Based on big data analysis, we developed "Llamanade, a user-friendly, open-source to facilitate rational humanization of Nbs. Using Nb sequence as input, Llamanade provides information on the sequence features, model structures, and optimizes solutions to humanize Nbs. The full analysis for a given Nb takes less than a minute on a local computer. To demonstrate the robustness of this tool, we applied it to successfully humanize a cohort of structurally diverse and highly potent SARS-CoV-2 neutralizing Nbs. Llamanade is freely available and will be easily accessible on a web server to support the development of a rapidly expanding repertoire of therapeutic Nbs into safe and effective trials. Author SummaryCamelid Nbs are characterized by small size, excellent pharmacological properties and high flexibility in bioengineering for therapeutic development. However, Nbs are "xeno" antibodies, which require "humanization" to improve their translational potential. Currently, there is a lack of systematic investigation of Nbs to rationally guide humanization. No dedicated software has been developed for this purpose. Here, we report the development of Llamanade, an open-source computational pipeline and the first dedicated software to facilitate rational humanization of Nbs. To subjectively evaluate Llamanade, we used it to humanize a cohort of structurally diverse and ultrapotent antiviral Nbs against SARS-CoV-2. Robust humanization by Llamanade significantly improved the humanness level of Nbs to closely resemble fully human IgGs. Importantly, these highly humanized antiviral Nbs remained excellent solubility and comparably high bioactivities to the non-humanized Nb precursors. We envision that Llamanade will help advance Nb research into therapeutic development.

bioinformatics↗

Deep learning-enhanced morphological profiling predicts cell fate dynamics in real-time in hPSCs

Predicting how stem cells become patterned and differentiated into target tissues is key for optimising human tissue design. Here, we established DEEP-MAP - for deep learning-enhanced morphological profiling - an approach that integrates single-cell, multi-day, multi-colour microscopy phenomics with deep learning and allows to robustly map and predict cell fate dynamics in real-time without a need for cell state-specific reporters. Using human pluripotent stem cells (hPSCs) engineered to co-express the histone H2B and two-colour FUCCI cell cycle reporters, we used DEEP-MAP to capture hundreds of morphological- and proliferation-associated features for hundreds of thousands of cells and used this information to map and predict spatiotemporally single-cell fate dynamics across germ layer cell fates. We show that DEEP-MAP predicts fate changes as early or earlier than transcription factor-based fate reporters, reveals the timing and existence of intermediate cell fates invisible to fixed-cell technologies, and identifies proliferative properties predictive of cell fate transitions. DEEP-MAP provides a versatile, universal strategy to map tissue evolution and organisation across many developmental and tissue engineering contexts.

cell biology↗

E3 ubiquitin ligase SYVN1 is a key positive regulator for GSDMD-mediated pyroptosis

Gasdermin D (GSDMD) participates in activation of inflammasomes and pyroptosis. Meanwhile, ubiquitination strictly regulates inflammatory responses. However, how ubiquitination regulates Gasdermin D activity is not well understood. In this study, we show that pyroptosis triggered by Gasdermin D is regulated through ubiquitination. Specifically, SYVN1, an E3 ubiquitin ligase of gasdermin D, promotes GSDMD-mediated pyroptosis. SYVN1 deficiency inhibits pyroptosis and subsequent LDH release and PI uptake. SYVN1 directly interacts with GSDMD, and mediates K27-linked polyubiquitination of GSDMD on K203 and K204 residues, promoting GSDMD-induced pyroptotic cell death. Thus, our findings revealed the essential role of SYVN1 in GSDMD-mediated pyroptosis. Overall, GSDMD ubiquitination is a potential therapeutic module for inflammatory diseases.

immunology↗

Nicotinic acid mononucleotide is an allosteric SARM1 inhibitor promoting axonal protection

SARM1 is an inducible NAD+ hydrolase that is the central executioner of pathological axon loss. Recently, we elucidated the molecular mechanism of SARM1 activation, demonstrating that SARM1 is a metabolic sensor regulated by the levels of NAD+ and its precursor, nicotinamide mononucleotide (NMN), via their competitive binding to an allosteric site within the SARM1 N-terminal ARM domain. In healthy neurons with abundant NAD+, binding of NAD+ blocks access of NMN to this allosteric site. However, with injury or disease the levels of the NAD+ biosynthetic enzyme NMNAT2 drop, increasing the NMN/ NAD+ ratio and thereby promoting NMN binding to the SARM1 allosteric site, which in turn induces a conformational change activating the SARM1 NAD+ hydrolase. Hence, NAD+ metabolites both regulate the activation of SARM1 and, in turn, are regulated by the SARM1 NAD+ hydrolase. This dual upstream and downstream role for NAD+ metabolites in SARM1 function has hindered mechanistic understanding of axoprotective mechanisms that manipulate the NAD+ metabolome. Here we reevaluate two methods that potently block axon degeneration via modulation of NAD+ related metabolites, 1) the administration of the NMN biosynthesis inhibitor FK866 in conjunction with the NAD+ precursor nicotinic acid riboside (NaR) and 2) the neuronal expression of the bacterial enzyme NMN deamidase. We find that these approaches not only lead to a decrease in the levels of the SARM1 activator NMN, but also an increase in the levels of the NAD+ precursor nicotinic acid mononucleotide (NaMN). We show that NaMN inhibits SARM1 activation, and demonstrate that this NaMN-mediated inhibition is important for the long-term axon protection induced by these treatments. Analysis of the NaMN-ARM domain co-crystal structure shows that NaMN competes with NMN for binding to the SARM1 allosteric site and promotes the open, autoinhibited configuration of SARM1 ARM domain. Together, these results demonstrate that the SARM1 allosteric pocket can bind a diverse set of metabolites including NMN, NAD+, and NaMN to monitor cellular NAD+ homeostasis and regulate SARM1 NAD+ hydrolase activity. The relative promiscuity of the allosteric site may enable the development of potent pharmacological inhibitors of SARM1 activation for the treatment of neurodegenerative disorders. HighlightsO_LINaMN binds to SARM1 N-terminal allosteric site and inhibits SARM1 NAD+ hydrolase C_LIO_LINaMN inhibits SARM1 activation by stabilizing its open, inactive structure C_LIO_LINMN deamidase promotes strong axonal protection by reducing NMN and increasing NaMN C_LI

neuroscience↗

Epigenetic regulator genes direct lineage switching in MLL-AF4 leukaemia

The fusion gene MLL-AF4 defines a high-risk subtype of pro-B acute lymphoblastic leukaemia. However, relapse can be associated with a switch from acute lymphoblastic to acute myeloid leukaemia. Here we show that these myeloid relapses share oncogene fusion breakpoints with their matched lymphoid presentations and can originate in either early, multipotent progenitors or committed B-cell precursors. Lineage switching is linked to substantial changes in chromatin accessibility and rewiring of transcriptional programmes indicating that the execution and maintenance of lymphoid lineage differentiation is impaired. We show that this subversion is recurrently associated with the dysregulation of repressive chromatin modifiers, notably the nucleosome remodelling and deacetylation complex, NuRD. In addition to mutations, we show differential expression or alternative splicing of NuRD members and other genes is able to reprogram the B lymphoid into a myeloid gene regulatory network. Lineage switching in MLL-AF4 leukaemia is therefore driven and maintained by defunct epigenetic regulation. Statement of SignificanceWe demonstrate diverse cellular origins of lineage switched relapse within MLL-AF4 pro-B acute leukaemia. Irrespective of the developmental origin of relapse, dysregulation of NuRD and/or other epigenetic machinery underpins fundamental lineage reprogramming with profound implications for the increasing use of epitope directed therapies in this high-risk leukaemia.

cancer biology↗

HepT1-derived murine models of high-risk hepatoblastoma display vascular invasion, metastasis, and circulating tumor cells

Hepatoblastoma (HB) is the most common pediatric primary liver malignancy, and survival for high-risk disease approaches 50%. Mouse models of HB fail to recapitulate hallmarks of high-risk disease. The aim of this work was to generate murine models that show high-risk features including multifocal tumors, vascular invasion, metastasis, and circulating tumor cells (CTCs). HepT1 cells were injected into the livers or tail veins of mice, and tumor growth was monitored with magnetic resonance and bioluminescent imaging. Blood was analyzed with fluorescence activated cell sorting to identify CTCs. Intra- and extra-hepatic tumor samples were harvested for immunohistochemistry and RNA and DNA sequencing. Cell lines were grown from tumor samples and profiled with RNA sequencing. With intrahepatic injection of HepT1 cells, 100% of animals grew liver tumors and showed vascular invasion, metastasis, and CTCs. Mutation profiling revealed genetic alterations in seven cancer-related genes, while transcriptomic analyses showed changes in gene expression with cells that invade vessels. Tail vein injection of HepT1 cells resulted in multifocal, metastatic disease. These unique models will facilitate further meaningful studies of high-risk HB. Summary StatementIn this work, we developed and thoroughly characterized several unique models of hepatoblastoma derived from the HepT1 cell line that show high-risk features.

cancer biology↗