Juxtacrine Research Articles

Light‐Based Juxtacrine Signaling Between Synthetic Cells

Cell signaling through direct physical cell–cell contacts plays vital roles in biology during development, angiogenesis, and immune response. Intercellular communication mechanisms between synthetic cells constructed from the bottom up are majorly reliant on diffusible chemical signals, thus limiting the range of responses in receiver cells. Engineering contact‐dependent signaling between synthetic cells promises to unlock more complicated signaling schemes with spatial responses. Herein, a light‐activated contact‐dependent communication scheme for synthetic cells is designed and demonstrated. A split luminescent protein is utilized to limit signal generation exclusively to contact interfaces of synthetic cells, driving the recruitment of a photoswitchable protein in receiver cells, akin to juxtacrine signaling in living cells. The modular design not only demonstrates contact‐dependent communication between synthetic cells but also provides a platform for engineering orthogonal contact‐dependent signaling mechanisms.

Long range juxtacrine signalling through cadherin for collective cell orientation

Many life phenomena, such as development, morphogenesis, tissue remodelling, and wound healing, are often driven by orderly and directional migration of collective cells. However, when cells are randomly oriented or localized disorder exists in orderly oriented collective cells, cell migration cannot occur in an orderly manner although various motion modes such as global rotation and local swirling and/or various motion patterns such as radial pattern and chiral pattern often occur. Therefore, it is important to control cell orientation to ensure the orderly migration of collective cells. Here, we show that it is not force transmission, but juxtacrine signalling through cadherin that plays a critical role in the orientation of collective cells. Surprisingly, juxtacrine signalling for cell orientation reached cells on a plastic dish that were not directly subjected to mechanical stimulation, up to 7 mm away from the actuator. The present study suggests that even weak mechanical stimulation is transmitted in a long range without force transmission through juxtacrine signalling. The long range juxtacrine signalling might play an important role in various life phenomena. Statement of SignificanceJuxtacrine signalling is direct cell-cell contact-dependent signalling, which plays a crucial role in cell behaviors such as mechanosensing, mechanotransduction and collective cell behaviors, however, there is not enough understanding about juxtacrine signalling. The present study has demonstrated that juxtacrine signalling for collective cell orientation is transmitted over a long range through cadherin. To the best of our knowledge, this is the first report of long range juxtacrine signalling. This finding may lead to the elucidation of various life phenomena such as development, morphogenesis, tissue remodelling, and wound healing.

Emergent order in epithelial sheets by interplay of cell divisions and cell fate regulation.

The fate choices of stem cells between self-renewal and differentiation are often tightly regulated by juxtacrine (cell-cell contact) signalling. Here, we assess how the interplay between cell division, cell fate choices, and juxtacrine signalling can affect the macroscopic ordering of cell types in self-renewing epithelial sheets, by studying a simple spatial cell fate model with cells being arranged on a 2D lattice. We show in this model that if cells commit to their fate directly upon cell division, macroscopic patches of cells of the same type emerge, if at least a small proportion of divisions are symmetric, except if signalling interactions are laterally inhibiting. In contrast, if cells are first 'licensed' to differentiate, yet retaining the possibility to return to their naive state, macroscopic order only emerges if the signalling strength exceeds a critical threshold: if then the signalling interactions are laterally inducing, macroscopic patches emerge as well. Lateral inhibition, on the other hand, can in that case generate periodic patterns of alternating cell types (checkerboard pattern), yet only if the proportion of symmetric divisions is sufficiently low. These results can be understood theoretically by an analogy to phase transitions in spin systems known from statistical physics.

Astrocytic DLL4-NOTCH1 signaling pathway promotes neuroinflammation via the IL-6-STAT3 axis

Under neuroinflammatory conditions, astrocytes acquire a reactive phenotype that drives acute inflammatory injury as well as chronic neurodegeneration. We hypothesized that astrocytic Delta-like 4 (DLL4) may interact with its receptor NOTCH1 on neighboring astrocytes to regulate astrocyte reactivity via downstream juxtacrine signaling pathways. Here we investigated the role of astrocytic DLL4 on neurovascular unit homeostasis under neuroinflammatory conditions. We probed for downstream effectors of the DLL4-NOTCH1 axis and targeted these for therapy in two models of CNS inflammatory disease. We first demonstrated that astrocytic DLL4 is upregulated during neuroinflammation, both in mice and humans, driving astrocyte reactivity and subsequent blood-brain barrier permeability and inflammatory infiltration. We then showed that the DLL4-mediated NOTCH1 signaling in astrocytes directly drives IL-6 levels, induces STAT3 phosphorylation promoting upregulation of astrocyte reactivity markers, pro-permeability factor secretion and consequent blood-brain barrier destabilization. Finally we revealed that blocking DLL4 with antibodies improves experimental autoimmune encephalomyelitis symptoms in mice, identifying a potential novel therapeutic strategy for CNS autoimmune demyelinating disease. As a general conclusion, this study demonstrates that DLL4-NOTCH1 signaling is not only a key pathway in vascular development and angiogenesis, but also in the control of astrocyte reactivity during neuroinflammation.

YAP/TAZ drives Notch and angiogenesis mechanoregulation in silico

Endothelial cells are key players in the cardiovascular system. Among other things, they are responsible for sprouting angiogenesis, the process of new blood vessel formation essential for both health and disease. Endothelial cells are strongly regulated by the juxtacrine signaling pathway Notch. Recent studies have shown that both Notch and angiogenesis are influenced by extracellular matrix stiffness; however, the underlying mechanisms are poorly understood. Here, we addressed this challenge by combining computational models of Notch signaling and YAP/TAZ, stiffness- and cytoskeleton-regulated mechanotransducers whose activity inhibits both Dll4 (Notch ligand) and LFng (Notch-Dll4 binding modulator). Our simulations successfully mimicked previous experiments, indicating that this YAP/TAZ-Notch crosstalk elucidates the Notch and angiogenesis mechanoresponse to stiffness. Additional simulations also identified possible strategies to control Notch activity and sprouting angiogenesis via cytoskeletal manipulations or spatial patterns of alternating stiffnesses. Our study thus inspires new experimental avenues and provides a promising modeling framework for further investigations into the role of Notch, YAP/TAZ, and mechanics in determining endothelial cell behavior during angiogenesis and similar processes.

Heterogeneous Kinetics of Nanobubble Ultrasound Contrast Agent and Angiogenic Signaling in Head and Neck Cancer.

Recently developed nanobubble ultrasound contrast agents are a promising tool for imaging and drug delivery in tumors. To better understand their unusual kinetics, we implemented a novel pixel clustering analysis, which provides unique information by accounting for spatial heterogeneity. By combining ultrasound results with proteomics of the imaged tumors, we show that this analysis is highly predictive of protein expression and that specific types of nanobubble time-intensity curve are associated with upregulation of different metabolic pathways. We applied this method to study the effects of two proteins, EphB4 and ephrinB2, which control tumor angiogenesis through bidirectional juxtacrine signaling, in mouse models of head and neck cancer. We show that ephrinB2 expression by endothelial cells and EphB4 expression by cancer cells have similar effects on tumor vasculature, despite sometimes opposite effects on tumor growth. This implicates a cancer-cell-intrinsic effect of EphB4 forward signaling and not angiogenesis in EphB4's action as a tumor suppressor.

Notch Signaling: An Emerging Paradigm in the Pathogenesis of Reproductive Disorders and Diverse Pathological Conditions.

The highly conserved Notch pathway, a pillar of juxtacrine signaling, orchestrates intricate intercellular communication, governing diverse developmental and homeostatic processes through a tightly regulated cascade of proteolytic cleavages. This pathway, culminating in the migration of the Notch intracellular domain (NICD) to the nucleus and the subsequent activation of downstream target genes, exerts a profound influence on a plethora of molecular processes, including cell cycle progression, lineage specification, cell-cell adhesion, and fate determination. Accumulating evidence underscores the pivotal role of Notch dysregulation, encompassing both gain and loss-of-function mutations, in the pathogenesis of numerous human diseases. This review delves deep into the multifaceted roles of Notch signaling in cellular dynamics, encompassing proliferation, differentiation, polarity maintenance, epithelial-mesenchymal transition (EMT), tissue regeneration/remodeling, and its intricate interplay with other signaling pathways. We then focus on the emerging landscape of Notch aberrations in gynecological pathologies predisposing individuals to infertility. By highlighting the exquisite conservation of Notch signaling in Drosophila and its power as a model organism, we pave the way for further dissection of disease mechanisms and potential therapeutic interventions through targeted modulation of this master regulatory pathway.

Cell membrane vesicles derived from hBMSCs and hUVECs enhance bone regeneration

Bone tissue renewal can be enhanced through co-transplantation of bone mesenchymal stem cells (BMSCs) and vascular endothelial cells (ECs). However, there are apparent limitations in stem cell-based therapy which hinder its clinic translation. Hence, we investigated the potential of alternative stem cell substitutes for facilitating bone regeneration. In this study, we successfully prepared cell membrane vesicles (CMVs) from BMSCs and ECs. The results showed that BMSC-derived cell membrane vesicles (BMSC-CMVs) possessed membrane receptors involved in juxtacrine signaling and growth factors derived from their parental cells. EC-derived cell membrane vesicles (EC-CMVs) also contained BMP2 and VEGF derived from their parental cells. BMSC-CMVs enhanced tube formation and migration ability of hUVECs, while EC-CMVs promoted the osteogenic differentiation of hBMSCs in vitro. Using a rat skull defect model, we found that co-transplantation of BMSC-CMVs and EC-CMVs could stimulate angiogenesis and bone formation in vivo. Therefore, our research might provide an innovative and feasible approach for cell-free therapy in bone tissue regeneration.

Abstract 777: Notch signaling dependent chemoresistance in racial disparity in ER+ breast cancer

Abstract Breast cancer (BCa) is the leading cause of cancer related death in women worldwide. The most common BCa subtype is the Estrogen/Progesterone receptor (ER+/PR+) luminal subtype, comprising up to 75% of all newly diagnosed BCa. Although these patients show initial benefit with chemotherapy and endocrine therapy, however, 40-50% of them eventually don’t respond to treatment due to resistance. Thus, the need for additional targeted therapies for this large subset of ER+ BCa patients is critical. Based on recent studies, it is observed that Afro-American (AA) patients experience substantially higher BCa mortality (40% more) than White American (WA) women in ER+ breast cancer. Unfortunately, the cause behind this difference in mortality in AA patients is not well understood. Notch signaling is a highly conserved intercellular communication mechanism critical for many cellular processes and is composed of several receptors and ligands. Recent data show that Notch receptors are overexpressed in hormone treatment refractory ER− patients of (Afro-American) AA origin, hinting connection of Notch signaling to racial disparity in breast cancer. Notch signaling is also identified in several metabolic disorders involving fatty acids and other lipids. However, function of Notch signaling in context of chemoresistance in AA ER+ breast cancer is still unknown. Using single cell sequencing, we found that chemo-resistant AA ER+ breast cancer patient samples have a distinct Notch signature enriched subpopulations in tumor cells, which was missing in WA patients. Notch signaling happens through juxtacrine signaling of ligand/receptor signaling. Further analysis in tumor microenvironment shows lipid enriched tumor associated macrophages, which are Notch dependent, suggesting potential crosstalk between lipid heavy tumor-macrophages and tumor cells, which may drive the chemoresistance in AA patients. Further analysis using patient derived explants, an attractive new tool for drug efficacy testing in ex vivo, we found that chemotherapy itself increases Notch signaling in the tumors. Ongoing studies involving scRNAseq, untargeted lipidomics and chemo-resistant PDE will delineate the precise mechanism of action between tumor cells and tumor associated lipid heavy macrophages in context of Notch signaling in chemo-resistant AA ER+ breast cancer. Citation Format: Shailesh Singh, Megha Das, Rumela Chakrabarti. Notch signaling dependent chemoresistance in racial disparity in ER+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 777.

Principles of Indirect Co-culture Method Using Transwell.

The co-culture method is a simple type of cell culture method used to evaluate the effects of communication between various types of cells in an in vitro setting. In the co-culture method, two or more eukaryotic cell types, or eukaryotic and prokaryotic cells, are cultured together. The co-culture method reflects in vivo cell behaviors and thereby emerges as a pivotal technique with diverse applications in cancer research and cell biology. Two categories of co-culture methods (indirect methods and direct methods) are well known. Direct co-culture methods allow physical contact between the various cell types (juxtacrine signaling). In indirect methods, cells are physically separated into two different populations (for example, using a Transwell) that allow communication only via secretory factors (paracrine signaling). Herein, we focus on the principles of the indirect co-culture method. Nowadays, this method is used to explore the effects of mesenchymal stem cell (MSC) secretome on cancer cells. These studies have unveiled intricate cell behavior dynamics, demonstrating how the MSC secretome influences cancer cell proliferation, invasion, apoptosis, and polarity.

Cell-cell communication in kidney fibrosis.

Kidney fibrosis is a common outcome of a wide variety of chronic kidney diseases, in which virtually all kinds of renal resident and infiltrating cells are involved. As such, well-orchestrated intercellular communication is of vital importance in coordinating complex actions during renal fibrogenesis. Cell-cell communication in multicellular organisms is traditionally assumed to be mediated by direct cell contact or soluble factors, including growth factors, cytokines and chemokines, through autocrine, paracrine, endocrine and juxtacrine signaling mechanisms. Growing evidence also demonstrates that extracellular vesicles, lipid bilayer-encircled particles naturally released from almost all types of cells, can act as a vehicle to transfer a diverse array of biomolecules including proteins, mRNA, miRNA and lipids to mediate cell-cell communication. We recently described a new mode of intercellular communication via building a special extracellular niche by insoluble matricellular proteins. Kidney cells, upon injury, produce and secrete different matricellular proteins, which incorporate into the local extracellular matrix network, and regulate the behavior, trajectory and fate of neighboring cells in a spatially confined fashion. This extracellular niche-mediated cell-cell communication is unique in that it restrains the crosstalk between cells within a particular locality. Detailed delineation of this unique manner of intercellular communication will help to elucidate the mechanism of kidney fibrosis and could offer novel insights in developing therapeutic intervention.

IL-1 alpha is myristoylated for monocyte surface translocation and promotes atherosclerosclerosis in mice

Abstract Background The role of Interleukin-1 alpha (IL-1α) and beta (IL-1β) in the pathogenesis of atherosclerosis in vivo has been controversial for years. In contrast to IL-1β, which is dependent on the NLR family pyrin domain containing 3 (NLRP3) inflammasome, IL-1α can be tethered to the plasma membrane (csIL-1α) where it exerts pro-inflammatory effects. We characterised the role of IL-1α and the Nlrp3 inflammasome in a nongenetic hyperlipidemic mouse model and examined the function of csIL-1α in human monocytes. Methods Atherosclerosis was induced by a single injection of mutant PCSK9-AAV8 virus in wild-type (WT, referred to as PCSK9-AAV), Il1a-/-, Nlrp3-/-, and Il1b-/- mice, in combination with high-fat western diet (21% fat, 0.2% cholesterol) for 12 weeks. Plaque size and lipid content, were histologically analysed. The serum proteome was studied using a targeted multiplex PEA (Olink Proteomics). Human primary monocytes and human umbilical vein endothelial cells (HUVECs) were used to examine csIL-1α-IL1R interaction by analyzing VCAM1 expression and monocyte adhesion. LPS was used to induce IL-1α protein synthesis and membrane translocation in vitro. Myristoylation was measured via flow cytometry. Results Il1a-/- animals showed significantly reduced atherosclerotic lesion size (-62% vs. PCSK9-AAV) and fat accumulation within the plaque (-64% vs. PCSK9-AAV). Knockout of Nlrp3 and IL-1β did not reduce plaque size or lipid content, indicating an Nlrp3-independent mechanism of the protective effect of Il1a-/-. Circulating pro-inflammatory cytokines such as IL-1α, IL-1β, and IL-6 were downregulated in serum of Il1a-/-, Nlrp3-/-, and Il1b-/- mice compared to PCSK9-AAV mice suggesting that the development of atherosclerotic plaques is independent of circulating inflammatory cytokines at an early stage. Therefore, we investigated the role of csIL-1α on human monocytes. Stimulation with LPS showed enrichment of csIL-1α by 13.2% (p<0.05) on monocytes without releasing IL-1α. Treatment of HUVECs with LPS-stimulated monocytes resulted in increased VCAM1 expression (+22.2%, p<0.05) and monocyte adhesion (1.9 fold, p<0.05) through a csIL-1α-IL1R interaction which was abolished by the addition of neutralising antibodies for IL1R1 and IL-1α (p<0.05, vs. LPS-treated monocytes). To investigate whether the IL-1α translocation is mediated by protein myristoylation, human monocytes were pre-incubated with the n-myristoyl-transferase inhibitor IMP-1088 before LPS stimulation, resulting in a reduction of csIL-1α expression (p<0.05, vs. LPS-treated monocytes). Conclusion This study demonstrated a protective effect of Il1a deficiency on the development of atherosclerosis. CsIL-1α mediates monocyte-to-endothelial adhesion by increasing VCAM1 expression through endothelial IL1R1 signaling. The data underscore the importance of the juxtacrine signaling of IL-1α and its role in the development of atherosclerosis independent of circulating cytokine levels.

Activation of periodontal ligament cell cytodifferentiation by juxtacrine signaling from cementoblasts.

New cementum forms from existing cementum during periodontal tissue regeneration, indicating that cementoblasts may interact with progenitor cells in the periodontal ligament to enhance cementogenesis. However, the molecular mechanisms of this process are currently unknown. This study aims to clarify the role of cell-cell interactions between cementoblasts and periodontal ligament cells in differentiation into cementoblasts. To analyze the role of human cementoblast-like cells (HCEMs) on human periodontal ligament cells (HPDLs), we mixed cell suspensions of enhanced green fluorescent protein-tagged HPDLs and HCEMs, and then seeded and cultured them in single wells (direct co-cultures). We sorted co-cultured HPDLs and analyzed their characteristics, including the expression of cementum-related genes. In addition, we cultured HPDLs and HCEMs in a non-contact environment using a culture system composed of an upper insert and a lower well separated by a semi-permeable membrane (indirect co-cultures), and similar analysis was performed. Gene expression of integrin-binding sialoprotein (IBSP) in cementoblasts was confirmed in mouse periodontal tissues. We also investigated the effect of Wingless-type (Wnt) signaling on the differentiation of HPDLs into cementoblasts. Direct co-culture of HPDLs with HCEMs significantly upregulated the expression of cementoblast-related genes in HPDLs, whereas indirect co-culture exerted no effect. Wnt3A stimulation significantly upregulated IBSP expression in HPDLs, whereas inhibition of canonical Wnt signaling suppressed the effects of co-culture. Our results suggest that direct cell interactions with cementoblasts promote periodontal ligament cell differentiation into cementoblasts. Juxtacrine signaling via the canonical Wnt pathway plays a role in this interaction.

Modelling the dynamics of senescence spread.

Cellular senescence is a cell surveillance mechanism that arrests the cell cycle in damaged cells. The senescent phenotype can spread from cell to cell through paracrine and juxtacrine signalling, but the dynamics of this process are not well understood. Although senescent cells are important in ageing, wound healing and cancer, it is unclear how the spread of senescence is contained in senescent lesions. In the absence of the immune system, senescence could theoretically spread infinitely from one cell to another, but this contradicts experimental evidence. To investigate this issue, we developed both a minimal mathematical model and a stochastic simulation of senescence spread. Our results suggest that differences in the number of signalling molecules secreted between subtypes of senescent cells can limit the spread of senescence. We found that dynamic, time-dependent paracrine signalling prevents the uncontrolled spread of senescence, and we demonstrate how model parameters can be determined using Bayesian inference in a proposed experiment.

Abstract A036: Juxtacrine signaling between macrophage and cancer cell inhibits radiation-induced ferroptosis in syngeneic colon cancer

Abstract Although radiotherapy (RT) is one of the most common modalities for cancer treatment, radioresistance remains an intractable challenge. RT induces intratumoral infiltration of macrophages for the clearance of injury debris, but rather tumor-associated macrophages confer fitness advantages to cancer cells after RT. Here, we report that tumor-associated macrophage instigates radioresistance by inhibiting RT-induced cell death in a contact-dependent manner. Mechanistically, RT increases receptor tyrosine kinases (RTKs) expression in cancer cells to enable direct interaction with macrophages, resulting in reduced cancer cell ferroptosis triggered by RT. Unbiased RNA-seq analysis of RTK-dependent juxtacrine signaling in macrophages further reveals a profound remodeling of the irradiated tumor microenvironment (TME) via regulation of macrophage polarization and cytotoxic T cell-mediated antitumor responses. Using a syngeneic colon cancer model, we found that ablation of RTK-induced juxtacrine signaling sensitized tumor to RT through increasing cancer cell ferroptosis and impairing macrophages-mediated TME. Collectively, our study supports the RTKs as a new radiosensitizing target via attenuation of the interaction between cancer cells and macrophages during RT. Citation Format: Sang Wha Kim, Hyewon Chung, Seung Hyeok Seok. Juxtacrine signaling between macrophage and cancer cell inhibits radiation-induced ferroptosis in syngeneic colon cancer [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A036.

The alternate ligand Jagged enhances the robustness of Notch signaling patterns.

The Notch pathway, an example of juxtacrine signaling, is an evolutionary conserved cell-cell communication mechanism. It governs emergent spatiotemporal patterning in tissues during development, wound healing and tumorigenesis. Communication occurs when Notch receptors of one cell bind to either of its ligands, Delta/Jagged of the neighboring cell. In general, Delta-mediated signaling drives neighboring cells to have an opposite fate (lateral inhibition) whereas Jagged-mediated signaling drives cells to maintain similar fates (lateral induction). Here, by deriving and solving a reduced set of 12 coupled ordinary differential equations for the Notch-Delta-Jagged system on a hexagonal grid of cells, we determine the allowed states across different parameter sets. We also show that Jagged (at low dose) acts synergistically with Delta to enable more robust pattern formation by making the neighboring cell states more distinct from each other, despite its lateral induction property. Our findings extend our understanding of the possible synergistic role of Jagged with Delta which had been previously proposed through experiments and models in the context of chick inner ear development. Finally, we show how Jagged can help to expand the bistable (both uniform and hexagon phases are stable) region, where a local perturbation can spread over time in an ordered manner to create a biologically relevant, perfectly ordered lateral inhibition pattern.

Abstract C045: CA19-9-mediated remodeling of the pancreatic tumor microenvironment

Abstract Pancreatic ductal adenocarcinoma (PDA) is an intractable common malignancy with a pro-tumorigenic and immunosuppressive microenvironment (ME) that often limits treatment efficacy. The glycan CA19-9 is used to follow treatment response in PDA patients, but its functional role in PDA remained unknown until recently because rodents lack this carbohydrate. CA19-9 elevation in a KRAS-mutant background promotes rapid progression to invasive carcinoma and induces ME remodeling in mice. The tumor ME includes cancer associated fibroblasts (CAFs) and tumor associated macrophages (TAMs) that contribute to desmoplasia, immunosuppression, and therapeutic resistance. All prior work investigating the tumor ME in PDA mouse models was performed in a CA19-9 negative context, potentially missing a key element of PDA biology. Elevation of CA19-9 in mice caused expansion of both CAFs and TAMs, but the mechanisms by which CA19-9 contributes to ME remodeling remains largely unknown. We aim to uncover the direct and indirect mechanisms of CA19-9-mediated ME remodeling. We identified CA19-9 modified ligands by immunoprecipitation and mass spectrometry that may contribute to reprogramming of the PDA ME. In addition to exploring changes in abundance, localization, and protein interactions, we will functionally characterize these candidate effectors via CRISPR ablation and antibody blockade using a novel Macrophage, Organoid, and Fibroblast (MOrF) co-culture platform. MOrF co-cultures can be sustained for at least 10 days in defined media conditions and enable compartment specific delineation of paracrine and juxtacrine signals. While CA19-9 modification may play a direct role in stromal remodeling, we also investigate effectors that are altered in response to CA19-9 elevation. CA19-9 induction in KRAS-mutant organoid mono-cultures increased gene expression of IL1α, CSF1,and TGFβ. In addition, CA19-9 expression increased gene set enrichment of inflammatory programs inorganoid mono-culture and led to increased expression of CAF and TAM differentiation programs in MOrF co-culture. These results are being validated as discussed above as well as by evaluation in vivo in CA19-9 positive and negative syngeneic orthotopic transplantation and autochthonous genetically engineered mouse models using scRNA-seq, pharmacologic and genetic perturbation, as well as other approaches. Using these orthogonal approaches, we will identify the mechanisms by which CA19-9 directly and indirectly contributes to PDA ME remodeling and ultimately, contributes to treatment response in the future. Citation Format: Jasper Hsu, Sejin Chung, Angelica E. Rock, Shira R. Okhovat, Dannielle D. Engle. CA19-9-mediated remodeling of the pancreatic tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C045.

CRISPR/Cas9-mediated deletion of Interleukin-30 suppresses IGF1 and CXCL5 and boosts SOCS3 reducing prostate cancer growth and mortality

BackgroundMetastatic prostate cancer (PC) is a leading cause of cancer death in men worldwide. Targeting of the culprits of disease progression is an unmet need. Interleukin (IL)-30 promotes PC onset and development, but whether it can be a suitable therapeutic target remains to be investigated. Here, we shed light on the relationship between IL30 and canonical PC driver genes and explored the anti-tumor potential of CRISPR/Cas9-mediated deletion of IL30.MethodsPC cell production of, and response to, IL30 was tested by flow cytometry, immunoelectron microscopy, invasion and migration assays and PCR arrays. Syngeneic and xenograft models were used to investigate the effects of IL30, and its deletion by CRISPR/Cas9 genome editing, on tumor growth. Bioinformatics of transcriptional data and immunopathology of PC samples were used to assess the translational value of the experimental findings.ResultsHuman membrane-bound IL30 promoted PC cell proliferation, invasion and migration in association with STAT1/STAT3 phosphorylation, similarly to its murine, but secreted, counterpart. Both human and murine IL30 regulated PC driver and immunity genes and shared the upregulation of oncogenes, BCL2 and NFKB1, immunoregulatory mediators, IL1A, TNF, TLR4, PTGS2, PD-L1, STAT3, and chemokine receptors, CCR2, CCR4, CXCR5. In human PC cells, IL30 improved the release of IGF1 and CXCL5, which mediated, via autocrine loops, its potent proliferative effect. Deletion of IL30 dramatically downregulated BCL2, NFKB1, STAT3, IGF1 and CXCL5, whereas tumor suppressors, primarily SOCS3, were upregulated. Syngeneic and xenograft PC models demonstrated IL30’s ability to boost cancer proliferation, vascularization and myeloid-derived cell infiltration, which were hindered, along with tumor growth and metastasis, by IL30 deletion, with improved host survival. RNA-Seq data from the PanCancer collection and immunohistochemistry of high-grade locally advanced PCs demonstrated an inverse association (chi-squared test, p = 0.0242) between IL30 and SOCS3 expression and a longer progression-free survival of patients with IL30NegSOCS3PosPC, when compared to patients with IL30PosSOCS3NegPC.ConclusionsMembrane-anchored IL30 expressed by human PC cells shares a tumor progression programs with its murine homolog and, via juxtacrine signals, steers a complex network of PC driver and immunity genes promoting prostate oncogenesis. The efficacy of CRISPR/Cas9-mediated targeting of IL30 in curbing PC progression paves the way for its clinical use.

Agent-Based Models Help Interpret Patterns of Clinical Drug Resistance by Contextualizing Competition Between Distinct Drug Failure Modes

Modern targeted cancer therapies are carefully crafted small molecules. These exquisite technologies exhibit an astonishing diversity of observed failure modes (drug resistance mechanisms) in the clinic. This diversity is surprising because back of the envelope calculations and classic modeling results in evolutionary dynamics suggest that the diversity in the modes of clinical drug resistance should be considerably smaller than what is observed. These same calculations suggest that the outgrowth of strong pre-existing genetic resistance mutations within a tumor should be ubiquitous.Yet, clinically relevantdrug resistance occurs in the absence of obvious resistance conferring genetic alterations. Quantitatively, understanding the underlying biological mechanisms of failure mode diversity may improve the next generation of targeted anticancer therapies. It also provides insights into how intratumoral heterogeneity might shape interpatient diversity during clinical relapse. We employed spatial agent-based models to explore regimes where spatial constraintsenable wild type cells (that encounter beneficial microenvironments)tocompete against genetically resistant subclones in the presence of therapy. In order to parameterize a model of microenvironmental resistance, BT20 cells were cultured in the presence and absence of fibroblasts from 16different tissues. The degree of resistance conferred by cancer associated fibroblasts in the tumor microenvironment was quantified by treating mono- and co-cultures with letrozole and then measuring the death rates. Our simulations indicate that, even when a mutation is more drug resistant, its outgrowth can be delayed byabundant,low magnitude microenvironmental resistance across large regions of a tumor that lack genetic resistance.These observations hold fordifferent modes of microenvironmental resistance, including juxtacrine signaling, soluble secreted factors,and remodeled ECM.This result helps to explain the remarkable diversity of resistance mechanisms observed in solid tumors, which subverts the presumption that the failure mode that causes the quantitatively fastest growth in the presence of drug should occur most often in the clinic. Our model results demonstrate that spatial effects can interact with low magnitude of resistance microenvironmental effects to successfully compete against genetic resistance that is orders of magnitude larger. Clinical outcomes of solid tumors are intrinsically connected to their spatial structure, and the tractability of spatial agent-based models like the ones presented here enable us to understand this relationship more completely.

Atypical induction of HIF-1α expression by pericellular Notch1 signaling suffices for the malignancy of glioblastoma multiforme cells

Contact-based pericellular interactions play important roles in cancer progression via juxtacrine signaling pathways. The present study revealed that hypoxia-inducible factor-1α (HIF-1α), induced even in non-hypoxic conditions by cell-to-cell contact, was a critical cue responsible for the malignant characteristics of glioblastoma multiforme (GBM) cells through Notch1 signaling. Densely cultured GBM cells showed enhanced viability and resistance to temozolomide (TMZ) compared to GBM cells at a low density. Ablating Notch1 signaling by a γ-secretase inhibitor or siRNA transfection resensitized resistant GBM cells to TMZ treatment and decreased their viability under dense culture conditions. The expression of HIF-1α was significantly elevated in highly dense GBM cells even under non-hypoxic conditions. Atypical HIF-1α expression was associated with the Notch1 signaling pathway in both GBM and glioblastoma stem cells (GSC). Proteasomal degradation of HIF-1α was prevented by binding with Notch1 intracellular domain (NICD), which translocated to the nuclei of GBM cells. Silencing Notch1 signaling using a doxycycline-inducible Notch1 RNA-interfering system or treatment with chetomin, a HIF pathway inhibitor, retarded tumor development with a significant anti-cancer effect in a murine U251-xenograft model. Using GBM patient tissue microarray analysis, a significant increase in HIF-1α expression was identified in the group with Notch1 expression compared to the group without Notch1 expression among those with positive HIF-1α expression. Collectively, these findings highlight the critical role of cell-to-cell contact-dependent signaling in GBM progression. They provide a rationale for targeting HIF-1α signaling even in a non-hypoxic microenvironment.