Biology subjects

Nasir, A.

Publications and source records attributed to Nasir, A..

At least 19 recordsLinked to original sources

bioRxiv2026

Efficient multi-lineage cardiovascular differentiation of human pluripotent stem cells in animal serum-free conditions

Human induced pluripotent stem cell (hiPSC) technologies offer human-relevant cardiac models for biomedical applications. However, workflows for differentiation of cardiac stromal cells and fabrication of engineered heart tissue (EHT) commonly rely on animal serum, contrary to growing policy demands to reduce use of these products. Applying marker analysis via COL1A, DDR2 and GATA4 for cardiac fibroblasts or CD31, CD34 and CD144 for endothelial cells, we tailored Panexin, a defined serum substitute, to support high efficiency differentiation of cardiac stromal lineages to 85% purity without additional purification steps. We evaluated fabrication of EHTs using hiPSC-cardiomyocytes only (monoculture) or further combined with cardiac fibroblasts and endothelial cells (triculture; 70%:15%:15%, respectively). Panexin poorly supported fabrication and contractility of EHTs, a finding unaltered by modulating spontaneous cardiac myofibroblast activation via TGF{beta} inhibition. In contrast, human serum enabled fabrication of mono- and tri-culture EHTs, wherein constructs made without TGF{beta} signalling inhibition delivered the strongest contractile forces (up to 0.25 mN) and exceeded comparator tissues engineered using animal serum. Our data show that iterative evaluation of serum substitutes, human serum, cell combinations and signalling pathway modulators can mitigate use of animal serum for functional EHT generation, aligning with the UK governments roadmap for alternative methods.

cell biology↗

bioRxiv2025

Egg colour mimicry in the common cuckoo results from coevolutionary alternation, not coevolutionary arms races

The exquisite eggshell mimicry found in many cuckoo-host systems has been the textbook example of a coevolutionary arms race1. In this system, cuckoos lay their eggs in their hosts nests leaving these foster parents to rear their young2. In defence, most of these hosts have evolved the ability to recognize cuckoo eggs. It is long-assumed that these interactions select for ever-improving eggshell mimicry in cuckoo host-races laying distinct eggs that specifically mimic their hosts eggshell, regardless of its particular colour3,4. We challenge this paradigm and demonstrate that coevolutionary arms races and egg colour mimicry are the exception to the rule. Here, using eggshell reflectance spectra from 39 host species and the specific cuckoo eggs found in their nests, we show that eggshell colour mimicry is very uncommon even among frequent hosts. Although cuckoo eggs display considerable variation in eggshell colour, their hosts eggshell colours occupy 6 times their colour volume. As a result, mimicry is only achieved for a small subset of the egg colour gamut. Furthermore, cuckoo host-races rarely lay eggs that match their hosts eggs better than those of other potential hosts or that are distinct from those laid by other cuckoo host-races. These patterns are inconsistent with the long-held assumption of coevolutionary arms races, but consistent with coevolutionary alternation that is defined by a process of continual host-switching. These findings open new avenues for research in a system that has long served as a model for studying coevolutionary processes.

evolutionary biology↗

bioRxiv2025

mRNA-1273.251 and mRNA-1283.251 vaccines expressing SARS-CoV-2 variant LP.8.1 antigens broadly neutralize contemporary JN.1-lineage viruses

The continued evolution of the SARS-CoV-2 Omicron JN.1 lineage has led to the emergence of antigenically distinct subvariants including KP.2, KP.3, XEC, and LP.8.1, which became the dominant strains in the Americas and Europe by mid-2025. LP.8.1 was designated a Variant Under Monitoring by the WHO in January 2025 due to its potential to displace prior circulating variants. Informed by early growth modeling and antigenic analysis, we selected LP.8.1 as a candidate strain for the 2025-2026 vaccine season. Here, we describe the development of updated LP.8.1-matched mRNA vaccine compositions encoding either the full-length spike protein for mRNA-1273 (monovalent) or the membrane-anchored receptor-binding and N-terminal domains for the mRNA-1283 vaccine. Initial in vitro characterization, including structural analysis, demonstrated robust antigen expression and intact antigenic features. Immunogenicity of both vaccines were evaluated in murine models following immunization as either a primary series in naive animals or as a booster dose. LP.8.1-matched vaccines elicited strong neutralizing antibody responses against the homologous LP.8.1 strain and more recently emerging JN.1-lineage subvariants, including XFG and NB.1.8.1. Notably, the mRNA-1283 vaccine expressing LP.8.1 induced higher mean neutralization titers than the mRNA-1273 version across multiple variants. These data demonstrate the immunogenicity and breadth of both LP.8.1-based mRNA-1273 and mRNA-1283 vaccines in the context of ongoing JN.1 lineage evolution and support the selection of LP.8.1 as the updated vaccine antigen for the 2025-2026 season.

immunology↗

bioRxiv2025

Multiple distinct metastatic cell states are induced by epithelial-mesenchymal plasticity

Epithelial-mesenchymal transition (EMT) enables epithelial cancer cells to acquire mesenchymal-associated traits that can promote invasion and metastasis. Although distinct EMT-associated states have been linked to invasive and metastatic behavior, it remains unclear when these states arise during primary tumor progression, how they diversify, and whether metastatic competence is restricted to a particular EMT phenotype. Using single-cell RNA sequencing in a genetically engineered mouse model of triple-negative breast cancer (TNBC), together with functional studies of tumor organoids, we reconstructed the emergence of EMT-associated heterogeneity during tumor progression. We found that early malignant cells first lost mammary lineage identity, generating lineage-altered epithelial states with increased intrinsic plasticity. Rather than progressing through a single EMT program, these plastic states diversified through ERK1/2-low and ERK1/2-high EMT-associated programs. These programs generated distinct hybrid epithelial-mesenchymal states in early tumors and more uniform mesenchymal-like subpopulations at later stages, with canonical EMT features, diminished plasticity, and highly invasive behavior. Importantly, metastatic competence was not restricted to a single EMT-associated state--both heterogeneous hybrid cells and more uniform mesenchymal-like cells initiated metastases, with metastatic lesions retaining features of their initiating populations. Together, our results show that EMT-associated heterogeneity in TNBC emerges through early lineage-state disruption followed by parallel regulatory programs that generate distinct metastatic cell states rather than converging on a single highly metastatic phenotype.

cancer biology↗

bioRxiv2025

Predictive Modeling of Immune Escape and Antigenic Grouping of SARS-CoV-2 Variants

The ongoing adaptive evolution of SARS-CoV-2 is characterized by the continued emergence of novel variants that escape from previously acquired infection- and/or vaccination-derived immunity. This continued SARS-CoV-2 variant evolution has necessitated annual vaccine updates to better match circulating viral variants. To optimize protection against emerging variants of interest and concern, a reliable means of predicting the immune escape of novel variants is needed to enable at-risk preparation of new vaccines. Herein, we describe the development and applications of a risk calculator that uses statistical modeling to predict the immune escape of emerging variants. The calculator utilizes previously published spike-antibody epitope and escape profiles and in vitro neutralization assessment of a large panel of pseudotyped SARS-CoV-2 variants evaluated against clinical sera. The calculator enables the grouping of antigenically related SARS-CoV-2 variants to guide strain selection for at-risk vaccine design and preparation, in anticipation of potential future requests by the global public health agencies. Here, we demonstrated the strain selection exercises for the XBB.1.5- and JN.1/KP.2-adapted mRNA-1273 COVID-19 vaccines in the 2023-2024 and 2024-2025 seasons, respectively, which were supported by both the risk calculator and preclinical and clinical immunogenicity data and were later recommended by the global public health agencies.

immunology↗

bioRxiv2025

Anti-Diabetic Effects of Nigella sativa and Cichorium intybus in Animal Experimental Model

Diabetes mellitus is a chronic metabolic disease in humans associated with severe complications with a significant impact on the health, life expectancy, and lifestyle of patients. The present study has been designed to examine the anti-hyperglycemic efficacy of two medicinal plants - Nigella sativa seeds and Cichorium intybus leaves - and their combined effects on body weight and hematological/serological parameters in alloxan-induced diabetic rabbits. For this purpose, 30 adult rabbits were divided into six equal groups of five rabbits each. Group I was kept as the negative control, while all other groups received a single intravenous injection of alloxan monohydrate to induce diabetes: Group II as positive control; Group III received metformin hydrochloride; Group IV was fed powdered C. intybus plant leaves; Group V was given N. sativa aqueous seeds extract; and Group VI was fed a combination of C. intybus and N. sativa. Fasting blood glucose levels and body weight of rabbits were observed at 0 days (before treatment) to Day 28 and regularly monitored during the four-week experimental trial. Biochemical analysis, serum insulin level, and hematological parameters were measured at the end of the experiment. Results showed that C. intybus, N. sativa, and their mixture significantly (p < 0.05) decreased the blood glucose levels, urea and creatinine levels, and enzyme levels in the blood. At the same time, body weight gain, red blood cell (RBC) count, white blood cell (WBC) count, and packed cell volume (PCV) % were increased in diabetic rabbits as compared with positive control rabbits. It was concluded that these plants have potential hypoglycemic effects and reduced diabetic complications in alloxan-induced diabetic rabbits. Further studies are needed to understand their potential for antidiabetic remedy.

pathology↗

bioRxiv2024

mRNA-1273 vaccines adapted to JN.1 or KP.2 elicit cross-neutralizing responses against the JN.1 sublineages of SARS-CoV-2 in mice

The continued diversification of SARS-CoV-2 omicron lineage has given rise to the JN.1 variant and descendant strains (KP.2, KP.3, and XEC) that have prolonged the JN.1 infection wave. JN.1 and KP.2 show decreased susceptibility to neutralization sera in recipients of XBB.1.5 vaccine boosters, supporting the recent authorization of JN.1- and KP.2-matched mRNA vaccines in the United States, Europe, and other regions. We evaluated the immunogenicity of two updated monovalent variant-containing formulations of mRNA-1273 vaccines encoding the spike protein of the omicron subvariants JN.1 (mRNA-1273.167) and KP.2 (mRNA-1273.712) as compared with the monovalent XBB.1.5 vaccine (mRNA-1273.815). The vaccines were administered either as a two-dose primary series in naive mice or as a booster (third) dose in mice previously immunized with two-dose primary series of mRNA-1273 (ancestral strain). The neutralizing antibody response elicited by these vaccines against JN.1 subvariants (KP.3 and LA.2) and the recombinant strain (XEC), which achieved dominance in the United States during late 2024, was evaluated. Primary series immunization with either JN.1- or KP.2-matched vaccine elicited robust neutralizing antibody titers against the matched strains and effectively cross-neutralized KP.3, LA.2, and XEC, but not the antigenically distant XBB.1.5. Similarly, JN.1- and KP.2-matched vaccines administered as a booster (third) dose increased titers against the corresponding strains and JN.1-related subvariants, but not against XBB.1.5. These data suggest these strains are antigenically similar with relatively few spike differences between JN.1 and KP.2/JN.1-related subvariants. Our results demonstrate the potency of JN.1- and KP.2-containing mRNA-1273 vaccines in neutralizing the matched variants and their utility in cross-neutralizing JN.1-related subvariants KP.3, LA.2, and XEC. Taken together, these data suggest that the licensed JN.1 and KP.2 mRNA vaccines are likely to continue to protect against the emerging strains as the JN.1 lineage further evolves.

immunology↗

bioRxiv2022

A monkeypox mRNA-lipid nanoparticle vaccine targeting virus binding, entry, and transmission drives protection against lethal orthopoxviral challenge

Monkeypox virus (MPXV) caused a global outbreak in 2022, fueled by behaviorally-altered and enhanced human-to-human transmission. While smallpox vaccines were rapidly deployed to curb spread and disease among those at highest risk, breakthrough disease was noted after complete immunization. Given the imminent threat of additional zoonotic events as well as the virus evolving ability to drive human-to-human transmission, there is an urgent need for the development of a MPXV-specific vaccine that is able to also confer broad protection against evolving strains and related orthopoxviruses. Here, we demonstrate that an mRNA-lipid nanoparticle vaccine encoding a set of four highly conserved MPXV surface proteins involved in virus attachment, entry and transmission can induce MPXV-specific immunity and heterologous protection against a lethal vaccinia virus (VACV) challenge. Compared to Modified Vaccinia Virus Ankara (MVA), which forms the basis for the current MPXV vaccine, mRNA-vaccination generated superior neutralizing and cellular spread-inhibitory activities against MPXV and VACV as well as greater Fc-effector Th1-biased humoral immunity to the four MPXV antigens and the four VACV homologs. Single MPXV antigen mRNA vaccines provided partial protection against VACV challenge, while combinations of two, three or four MPXV antigen expressing mRNAs protected against disease-related weight loss and death. Remarkably, the cross-protection by multivalent MPXV mRNAs was superior to the homologous protection by MVA, associated with a combination of neutralizing and non-neutralizing antibody functions. These data reveal robust protection against VACV using an mRNA-based vaccine targeting four highly conserved viral surface antigens, linked to the induction of highly functional antibodies able to rapidly control viral infection.

immunology↗

bioRxiv2022

Cross-sectional study of antimicrobial resistance and ecology in gastrointestinal and oral microbial communities of urban Pakistani adults

Background and AimsAntimicrobial resistance (AMR) is one of the most serious global public health threats affecting lower-middle-income countries (LMICs) due to lack of awareness, inadequate healthcare and sanitation infrastructure, plus other environmental factors. In this study, we aimed to link microbial assembly and covariates (body mass index, smoking, use of antibiotics) to gut microbiome structure and correlate AMR gene prevalence. MethodsWe examined the gastrointestinal and oral microbial profiles of healthy adults in Pakistan through 16S rRNA gene sequencing with a focus on different ethnicities, antibiotic usage, drinking water type, smoking, and other demographic measures. We then utilised a suite of innovative statistical tools, driven by numerical ecology and machine learning, to address the above aims. ResultsWe observed tap water as the main contributor for development of AMR in the Pakistani cohort. In addition, microbial niche breadth analysis based on null modelling procedures highlighted an aberrant gut microbial signature of smokers with increased age. ConclusionsDrinking water plays a more important role in AMR spread in Pakistan rather than other factors considered. Moreover, covariates such as smoking, and age impact the human microbial community structure in this Pakistani cohort. To the best of our knowledge, this is one of the first studies that provide a snapshot of the microbiomes of healthy individuals in Pakistan and considers AMR profiles with an emphasis on potential sources of AMR prevalence. Background and ContextPakistan is categorized as a low-and-middle-income country by the World Bank where misuse of antibiotics is widespread, and multidrug resistance is prevalent. Thus, it is imperative that we understand antimicrobial resistance and the drivers of human microbiomes in Pakistan. New FindingsIn a healthy Pakistani cohort, individuals that consumed Tap Water had almost 6-fold more associations with AMRs. Therefore, drinking water source could be a strong driver in the spread of AMR. LimitationsA limitation is the use of predictive functional profiles. However, shotgun metagenomics may be prohibitively costly for LMICs given the urgent need for AMR surveillance. Clinical Research RelevanceOur research shows strong associations of key microbial taxa with covariates such as age, BMI, and gender. Additionally, we show correlations between specific outlier taxa that are present both in the gut and oral communities, highlighting potential future feasibility for use of the oral microbiome as a proxy to gut dysbiosis in some cases. Basic Research RelevanceWe have applied recent advancements in analytical tools to link both AMR prevalence and human microbiome composition with factors such as age, BMI, gender, ethnicity, smoking status, use of antibiotics, and drinking water source. Additionally, we use null modelling to show that the microbial communities are subject to strong environmental pressure and dispersal limitation. Lay SummaryWe analysed gut and oral microbes from healthy individuals in Pakistan and found that the potential for antibiotic resistance was increased in those who drank tap water.

microbiology↗

bioRxiv2022

Bivalent SARS-CoV-2 mRNA vaccines increase breadth of neutralization and protect against the BA.5 Omicron variant

The emergence of SARS-CoV-2 variants in the Omicron lineage with large numbers of substitutions in the spike protein that can evade antibody neutralization has resulted in diminished vaccine efficacy and persistent transmission. One strategy to broaden vaccine-induced immunity is to administer bivalent vaccines that encode for spike proteins from both historical and newly-emerged variant strains. Here, we evaluated the immunogenicity and protective efficacy of two bivalent vaccines that recently were authorized for use in Europe and the United States and contain two mRNAs encoding Wuhan-1 and either BA.1 (mRNA-1273.214) or BA.4/5 (mRNA-1273.222) spike proteins. As a primary immunization series in BALB/c mice, both bivalent vaccines induced broader neutralizing antibody responses than the constituent monovalent vaccines (mRNA-1273 [Wuhan-1], mRNA-1273.529 [BA.1], and mRNA-1273-045 [BA.4/5]). When administered to K18-hACE2 transgenic mice as a booster at 7 months after the primary vaccination series with mRNA-1273, the bivalent vaccines induced greater breadth and magnitude of neutralizing antibodies compared to an mRNA-1273 booster. Moreover, the response in bivalent vaccine-boosted mice was associated with increased protection against BA.5 infection and inflammation in the lung. Thus, boosting with bivalent Omicron-based mRNA-1273.214 or mRNA-1273.222 vaccines enhances immunogenicity and protection against currently circulating SARS-CoV-2 strains.

microbiology↗

bioRxiv2021

Zebrafish xenografts to isolate unique human breast cancer metastatic cell populations

Cancer metastasis is a critical culprit frequently blamed for treatment failure, drug resistance, poor prognosis, and high mortality rate among all human cancers. Laboratory efforts to isolate metastatic cell populations have typically been confined to mouse models, which are time-consuming and expensive. Here, we present a model system based on xenografting zebrafish embryos to select for cells that are predisposed to progress through the early stages of metastasis. This model requires only 3-5 days to achieve distinct intravasation to the zebrafish circulatory system. The metastatic cells are easily tracked in real-time as they migrate, as well as isolated and propagated in vitro. Once expanded, molecular characterization of the serially derived invasive cell populations from the tails of the zebrafish accurately predicts genes, signaling pathways, protein-protein interactions, and differential splicing products that are important for an invasive phenotype. This zebrafish model therefore offers a high-throughput and robust method for identifying gene targets critical for cancer metastasis.

cancer biology↗

bioRxiv2021

Tip growth in the brown alga Ectocarpus is controlled by a RHO-GAP-BAR domain protein independently from F-actin organisation

The brown alga Ectocarpus is a filamentous seaweed that grows by tip growth and branching. In the morphometric mutant etoile, tip growth is slower than in the WT and eventually stops. In this paper, we show that the causal etoile mutation is a null mutation in a bi-domain BAR-RhoGAP gene. By quantitative RT-PCR, we showed that ETOILE is ubiquitously expressed in prostrate filaments of the Ectocarpus sporophyte, and is downregulated in the etoile mutant. We immunolocalised both domains of the protein in WT and etoile, as well as RAC1, the known target of Rho-GAP enzymes. Thus, ETOILE would be localised at the apical cell dome where it would control the localisation of EsRAC1 to the plasma membrane. Actin staining showed that the mutant is not affected in F-actin structures. Overall, these results suggest that in Ectocarpus, BAR-RhoGAP controls tip growth by controlling RAC1 localization and through an actin-independent mechanism.

developmental biology↗

bioRxiv2021

Fibroblast activation protein regulates natural killer cell migration, extravasation and tumor infiltration

Natural killer (NK) cells play a critical role in physiologic and pathologic conditions such as pregnancy, infection, autoimmune disease and cancer. In cancer, numerous strategies have been designed to exploit the cytolytic properties of NK cells, with variable success. A major hurdle to NK-cell focused therapies is NK cell recruitment and infiltration into tumors. While the chemotaxis pathways regulating NK recruitment to different tissues are well delineated, the mechanisms human NK cells employ to physically migrate are ill-defined. We show for the first time that human NK cells express fibroblast activation protein (FAP), a cell surface protease previously thought to be primarily expressed by activated fibroblasts. FAP degrades the extracellular matrix to facilitate cell migration and tissue remodeling. We used novel in vivo zebrafish and in vitro 3D culture models to demonstrate that FAP knock out and pharmacologic inhibition restrict NK cell migration, extravasation, and invasion through tissue matrix. Notably, forced overexpression of FAP promotes NK cell invasion through matrix in both transwell and tumor spheroid assays, ultimately increasing tumor cell lysis. Additionally, FAP overexpression enhances NK cells invasion into a human tumor in immunodeficient mice. These findings demonstrate the necessity of FAP in NK cell migration and present a new approach to modulate NK cell trafficking and enhance cell-based therapy in solid tumors. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/429622v3_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@d6d9e5org.highwire.dtl.DTLVardef@17b6790org.highwire.dtl.DTLVardef@cc581eorg.highwire.dtl.DTLVardef@1ad2129_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2020

Fra1 is required for TGFβ1 induced collective invasion

Phenotypic heterogeneity promotes tumor evolution and confounds treatment. Minority subpopulations of trailblazer cells enhance the heterogeneity of invading populations by creating paths in extracellular matrix (ECM) that permit the invasion of phenotypically diverse siblings. The regulatory programs that induce a trailblazer state are poorly understood. Here, we define a new Tgf{beta} induced trailblazer population that is more aggressive than previously characterized Keratin 14 expressing trailblazer cells. Rather than triggering a binary switch to a single trailblazer state, Tgf{beta} induced multiple unique states that were distinguished by their expression of regulatory transcription factors, genes involved in ECM reorganization and capacity to initiate collective invasion. The integration of a parallel Egfr signaling program was necessary to induce pro-motility genes and could be targeted with clinically approved drugs to prevent trailblazer invasion. Surprisingly, Egfr pathway activity also had the collateral consequence of antagonizing the expression of a cohort of Tgf{beta} induced genes, including a subset involved in ECM remodeling. Together, our results reveal a new compromise mode of signal integration that promotes a trailblazer state and can be therapeutically targeted to prevent collective invasion.

cancer biology↗

bioRxiv2020

Discovery of a Novel Polymer for Xeno-free, Long-term Culture of Human Pluripotent Stem Cell Expansion

Human pluripotent stem cells (hPSCs) can be expanded and differentiated in vitro into almost any adult tissue cell type, and thus have great potential as a source for cell therapies with biomedical application. In this study, a fully-defined polymer synthetic substrate is identified for hPSC culture in completely defined, xeno-free conditions. This system can overcome the cost, scalability and reproducibility limitations of current hPSC culture strategies, and facilitate large-scale production. A high-throughput, multi-generational polymer microarray platform approach was used to test over 600 unique polymers and rapidly assess hPSC-polymer interactions in combination with the fully defined xeno-free medium, Essential 8TM (E8). This study identifies as novel nanoscale phase separated blend of poly(tricyclodecane-dimethanol diacrylate) and poly(butyl acrylate) (2:1 v/v), which supports long-term expansion of hPSCs and can be readily coated onto standard cultureware. Analysis of cell-polymer interface interactions through mass spectrometry and integrin blocking studies provides novel mechanistic insight into the role of the E8 proteins in promoting integrin-mediated hPSC attachment and maintaining hPSC signaling, including ability to undergo multi-lineage differentiation. This study therefore identifies a novel substrate for long-term serial passaging of hPSCs in serum-free, commercial chemically-defined E8, which provides a promising and economic hPSC expansion platform for clinical-scale application.

synthetic biology↗

bioRxiv2020

SARS-CoV-2 genome analysis of strains in Pakistan reveals GH, S and L clade strains at the start of the pandemic

ObjectivesPakistan has a high infectious disease burden with about 265,000 reported cases of COVID-19. We investigated the genomic diversity of SARS-CoV-2 strains and present the first data on viruses circulating in the country. MethodsWe performed whole-genome sequencing and data analysis of SARS-CoV-2 eleven strains isolated in March and May. ResultsStrains from travelers clustered with those from China, Saudi Arabia, India, USA and Australia. Five of eight SARS-CoV-2 strains were GH clade with Spike glycoprotein D614G, Ns3 gene Q57H, and RNA dependent RNA polymerase (RdRp) P4715L mutations. Two were S (ORF8 L84S and N S202N) and three were L clade and one was an I clade strain. One GH and one L strain each displayed Orf1ab L3606F indicating further evolutionary transitions. ConclusionsThis data reveals SARS-CoV-2 strains of L, G, S and I have been circulating in Pakistan from March, at the start of the pandemic. It indicates viral diversity regarding infection in this populous region. Continuing molecular genomic surveillance of SARS-CoV-2 in the context of disease severity will be important to understand virus transmission patterns and host related determinants of COVID-19 in Pakistan.

genomics↗

bioRxiv2020

Paternal exposure to DDT programs breast cancer development in daughters via sperm miRNA in a mouse model

DNA sequence accounts for the majority of disease heritability, including cancer. Yet, not all familial cancer cases can be explained by genetic factors. It is becoming clear that environmentally induced epigenetic inheritance occurs and that the progenys traits can be shaped by parental environmental experiences. In humans, epidemiological studies have implicated environmental toxicants, such as the pesticide DDT, in intergenerational cancer development, including breast and childhood tumors. Here, we show that the female progeny of males exposed to DDT in the pre-conception period have higher susceptibility to developing aggressive tumors in mouse models of breast cancer. Sperm of DDT-exposed males exhibited distinct patterns of small non-coding RNAs, with an increase in miRNAs and a specific surge in miRNA-10b levels. Remarkably, embryonic injection of the entire sperm RNA load of DDT-exposed males, or synthetic miRNA-10b, recapitulated the tumor phenotypes observed in DDT offspring. Mechanistically, miR-10b injection altered the transcriptional profile in early embryos with enrichment of genes associated with cell differentiation, tissue and immune system development. In adult DDT-derived progeny, transcriptional and protein analysis of mammary tumors revealed alterations in stromal and in immune system compartments. Our findings reveal a causal role for sperm RNAs in environmentally induced inheritance of cancer predisposition and, if confirmed in humans, this could help partially explain some of the "missing heritability" of breast, and other, malignancies.

cancer biology↗

bioRxiv2020

Inflammation promotes tumor aggression by stimulating stromal cell-dependent collagen crosslinking and stromal stiffening

Collagen deposition and stromal stiffening accompany malignancy, compromise treatment, and promote tumor aggression. Clarifying the molecular nature of and the factors that regulate extracellular matrix stiffening in tumors should identify biomarkers to stratify patients for therapy and therapeutic interventions to improve outcome. We profiled lysyl hydroxylase- and lysyl oxidase-mediated collagen crosslinks and quantified the greatest abundance of total and complex collagen crosslinks in more aggressive human breast cancer subtypes with the stiffest stroma. These tissues also harbored the highest number of tumor-associated macrophages (TAM), whose therapeutic ablation not only reduced metastasis, but also concomitantly decreased accumulation of collagen crosslinks and stromal stiffening. Epithelial-targeted expression of the crosslinking enzyme lysyl oxidase had no impact on collagen crosslinking in PyMT mammary tumors, whereas stromal cell targeting did. Consistently, stromal cells in microdissected human tumors expressed the highest level of collagen crosslinking enzymes. Immunohistochemical analysis of a cohort of breast cancer patient biopsies revealed that stromal expression of lysyl hydroxylase two, an enzyme that induces hydroxylysine aldehyde-derived collagen crosslinks and stromal stiffening correlated significantly disease specific mortality. The findings link tissue inflammation, stromal cell-mediated collagen crosslinking and stiffening to tumor aggression and identify lysyl hydroxylase two as a novel stromal biomarker. SignificanceWe show infiltrating macrophages induce stromal fibroblast, and not epithelial, expression of collagen crosslinking enzymes that drive tumor stiffening. Stromal enzyme LH2 is significantly upregulated in breast cancer patients with the stiffest stroma, the most trivalent HLCCs and the worst prognosis, underscoring its potential as a biomarker and therapeutic target.

cancer biology↗