Crosstalk Research Articles

VCAM-1 mediates proximal tubule-immune cell cross talk in failed tubule recovery during AKI-to-CKD transition.

Studies in animal models have suggested a linkage between the inflammatory response to injury and subsequent nephron loss during the acute kidney injury (AKI) to chronic kidney disease (CKD) transition. Failure of normal repair during the CKD transition correlates with de novo expression of vascular cell adhesion protein-1 (VCAM-1) by a subset of injured proximal tubule cells. This study identified the role of VCAM-1 expression in promoting the failed repair state. Single-cell transcriptome analysis of patients with AKI and CKD and whole kidney RNA and protein analyses of mouse models of CKD confirmed a marked increase of VCAM-1 expression in the proximal tubules of injured kidneys. In immortalized mouse proximal tubular cells and primary cultured renal cells (PCRCs), VCAM-1 expression was induced by proinflammatory cytokines including tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Analyses of bulk RNA sequencing of TNF-α-treated primary cultured renal cells or pseudo-bulk RNA sequencing of biopsies from Kidney Precision Medicine Project datasets indicated activation of NF-κB and an enrichment of inflammatory response and cell adhesion pathways in VCAM-1-positive cells. Pharmacological inhibition of NF-κB signaling or genetic deletion of myeloid differentiation factor 88 and TIR domain-containing adapter-inducing interferon-β suppressed TNF-α- and IL-1β-induced VCAM-1 expression in vitro. TNF-α stimulation or overexpression of VCAM-1 significantly increased splenocyte adhesion to the mouse proximal tubular monolayer in culture. These results demonstrate that persistence of proinflammatory cytokines after AKI can induce NF-κB-dependent VCAM-1 expression by proximal tubule cells, mediating increased immune cell adhesion to the tubule and thus promoting further tubule injury and greater risk of progression from AKI to CKD.NEW & NOTEWORTHY We demonstrated the induction of VCAM-1 and its biological function in proximal tubules. We found that proinflammatory cytokines (TNF-α and IL-1β) significantly induced VCAM-1 expression via NF-κB signaling pathway. TNF-α treatment or overexpression of VCAM-1 in immortalized MPT cells increased CD45+ splenocyte adhesion. Pharmacological inhibition of NF-κB or genetic deletion of Vcam1 suppressed TNF-α-induced splenocyte adhesion in vitro, suggesting that VCAM-1 mediates proximal tubular-immune cell cross talk in failed tubule recovery during AKI-to-CKD transition.

Platelet-derived extracellular vesicles in cardiovascular disease and treatment - from maintaining homeostasis to targeted drug delivery.

Cardiovascular disease (CVD) remains a major global health burden. Rising incidences necessitate improved understanding of the pathophysiological processes underlying disease progression to foster the development of novel therapeutic strategies. Besides their well recognized role in CVD, platelet-derived extracellular vesicles (PEVs) mediate inter-organ cross talk and contribute to various inflammatory diseases. PEVs are readily accessible diagnostic biomarkers that mirror pathophysiological disease progression but also may confer cardioprotective properties. Monitoring the effects of modulation of PEV signatures through pharmacotherapies has also provided novel insights into treatment efficacy. Furthermore, exploiting their inherent ability to infiltrate thrombi, atherosclerotic plaques and solid tumours, PEVs as well as platelet-membrane coated nanoparticles are emerging as novel effective and targeted treatment options for CVD and cancer. Collectively, in-depth characterization of PEVs in various diseases ultimately enhances their use as diagnostic or prognostic biomarkers and potential therapeutic targets, making them clinically relevant candidates to positively impact patient outcomes.

Myoblast-Derived Galectin 3 Impairs the Early Phases of Osteogenesis Affecting Notch and Akt Activity.

Galectin-3 (Gal-3) is a pleiotropic lectin produced by most cell types, which regulates multiple cellular processes in various tissues. In bone, depending on its cellular localization, Gal-3 has a dual and opposite role. If, on the one hand, intracellular Gal-3 promotes bone formation, on the other, its circulating form affects bone remodeling, antagonizing osteoblast differentiation and increasing osteoclast activity. From an analysis of the secretome of cultured differentiating myoblasts, we interestingly found the presence of Gal-3. After that, we confirmed that Gal-3 was expressed and released in the extracellular environment from myoblast cells during their differentiation into myotubes, as well as after mechanical strain. An in vivo analysis revealed that Gal-3 was triggered by trained exercise and was specifically produced by fast muscle fibers. Speculating a role for this peptide in the muscle-to-bone cross talk, a direct co-culture in vitro system, simultaneously combining media that were obtained from differentiated myoblasts and osteoblast cells, confirmed that Gal-3 is a mediator of osteoblast differentiation. Molecular and proteomic analyses revealed that the secreted Gal-3 modulated the biochemical processes occurring in the early phases of bone formation, in particular impairing the activity of the STAT3 and PDK1/Akt signaling pathways and, at the same time, triggering that one of Notch. Circulating Gal-3 also affected the expression of the most common factors involved in osteogenetic processes, including BMP-2, -6, and -7. Intriguingly, Gal-3 was able to interfere with the ability of differentiating osteoblasts to interact with the components of the extracellular bone matrix, a crucial condition required for a proper osteoblast differentiation. All in all, our evidence lays the foundation for further studies to present this lectin as a novel myokine involved in muscle-to-bone crosstalk.

Extended S2 diagnosis of mode degradation in fiber components through group delay stretching.

The separate diagnosis of mode degradation in few-mode fiber components (FMFCs) is a challenging task due to the reciprocal mode cross talk. In this work, we propose the group delay stretching, combined with the extended spatially and spectrally (S2) resolved imaging technique, to decouple and analyze the mode coupling within the body of the FMFC with short-length pigtails. Through stretching the mode delay by a delay fiber, the degraded modes related to different origins are effectively separated, and the extended S2 technique quantifies the individual modal weight for each component. Experiments on different types of FMFCs have verified the validity of our method. This method paves the way for optimizing and manipulating the fiber components in the dimensionality of modes.

Different-Mode Power Splitters for Optical Testing of Three-Channel and Dual-Mode Waveguide Crossing

We study that the different-mode (waveguide-connected) power splitter [(W)PS] can provide different-mode testing points for the optical testing. With the PS or WPS providing two different-mode testing points, the measured insertion losses (ILs) of the three-channel and dual-mode waveguide crossing (WC) for both the fundamental transverse electric (TE0) and TE1 modes are less than 1.8 dB or 1.9 dB from 1540 nm to 1560 nm. At the same time, the crosstalks (CTs) are lower than −17.4 dB or −18.2 dB. The consistent test results indicate the accuracy of the (W)PS-based testing circuit. Additionally, combining the tunable tap couplers, the (W)PS can provide multiple testing points with different modes and different transmittances.

Interaction of acoustic waves with spin waves using a GHz operating GaN/Si SAW device with a Ni/NiFeSi layer between its IDTs.

A two port surface acoustic wave (SAW) device was developed to be used for the control and excitation via spin waves (SW). The structure was manufactured using advanced nanolithography techniques, on GaN/Si, enabling fundamental Rayleigh interdigitated transducer (IDT) resonances in GHz frequency range. The ferromagnetic resonance of the magnetostrictive Ni/NiFeSi layer placed between the IDTs of the SAW device can be tuned to the SAW resonance frequency by magnetic fields. Using structures with finger and interdigit spacing of 170 nm and 100 nm, fundamental Rayleigh IDT resonance frequencies of 6.4 and 10.4 GHz have been obtained. Coupling of SAW to SW was demonstrated through transmission measurements at the fundamental Rayleigh frequencies in a magnetic field, μ0H from -280 to +280 mT, at different angles (θ) between the SAW propagation direction and the magnetic field direction. For the 6.4 GHz resonator a maximum decrease of about 1.2 dB occurred in |S21|, at μ0H = 30 mT and at θ = 45. Time-gated processing of the frequency domain raw data was used to remove the direct electromagnetic cross talk and triple transit effects. Nonreciprocity associated to the coupling was analyzed for the two SAW structures. The quantitative influence of the magnetic field strength on the phase of the transmission parameters is also presented.

Proteomic Characterization of Corneal Epithelial and Stromal Cell-Derived Extracellular Vesicles.

Communication between the different layers of the cornea (epithelium and stroma) is a complex, yet crucial element in the corneal healing process. Upon corneal injury, it has been reported that the bi-directional cross talk between the epithelium and stroma via the vesicular secretome, namely, extracellular vesicles (EVs), can lead to accelerated wound closure upon injury. However, the distinct protein markers of EVs derived from human corneal epithelial (HCE) cells, keratocytes (HCKs), fibroblasts (HCFs), and myofibroblasts (HCMs) remain poorly understood. All EVs were enriched for CD81 and showed increased expression levels of ITGAV and FN1 in HCM-EVs compared to HCE- and HCF-EVs. All EVs were negative for GM130 and showed minimal differences in biophysical properties (particle concentration, median particle size, and zeta potential). At the proteomic level, we show that HCM-EVs are enriched with proteins associated with fibrosis pathways, such as COL6A1, COL6A2, MMP1, MMP2, TIMP1, and TIMP2, compared to HCE-, HCK-, and HCF-EVs. Interestingly, HCE-EVs express proteins involved with the EIF-2 signaling pathway (stress-induced signals to regulate mRNA translation), such as RPS21, RALB, EIF3H, RALA, and others, compared to HCK-, HCF-, and HCM-EVs. In this study, we isolated EVs from cell-conditioned media from HCE, HCKs, HCFs, and HCMs and characterized their biophysical and protein composition by Western blot, nanoparticle tracking analysis, and proteomics. This study supports the view that EVs from the corneal epithelium and stroma have a distinct molecular composition and may provide novel protein markers to distinguish the difference between HCE-, HCK-, HCF-, and HCM-EVs.

TRIM25, TRIM28 and TRIM59 and Their Protein Partners in Cancer Signaling Crosstalk: Potential Novel Therapeutic Targets for Cancer.

Aberrant expression of TRIM proteins has been correlated with poor prognosis and metastasis in many cancers, with many TRIM proteins acting as key oncogenic factors. TRIM proteins are actively involved in many cancer signaling pathways, such as p53, Akt, NF-κB, MAPK, TGFβ, JAK/STAT, AMPK and Wnt/β-catenin. Therefore, this review attempts to summarize how three of the most studied TRIMs in recent years (i.e., TRIM25, TRIM28 and TRIM59) are involved directly and indirectly in the crosstalk between the signaling pathways. A brief overview of the key signaling pathways involved and their general cross talking is discussed. In addition, the direct interacting protein partners of these TRIM proteins are also highlighted in this review to give a picture of the potential protein-protein interaction that can be targeted for future discovery and for the development of novel therapeutics against cancer. This includes some examples of protein partners which have been proposed to be master switches to various cancer signaling pathways.

Bifunctional mitochondria-targeting fluorescence probe for in vivo ONOO− and viscosity sensing without signal crosstalk

Viscosity is an important mitochondrial micro-environmental parameter, and peroxynitrite (ONOO−) is one type of reactive oxygen species (ROS), both of which play critical roles in cellular activities. Abnormalities in mitochondrial viscosity or aberrant concentration of ONOO− can lead to mitochondrial dysfunctions and diseases. Here, by incorporating different substituents into the xanthene core, we develop three molecular probes P1, P2 and P3, all of which are dual-responsive to viscosity and ONOO−. Among P1-P3, the probe P2 displays large fluorescence enhancements of 49-fold for viscosity (at 819 nm) and 66-fold for ONOO− (at 511 nm), respectively. More importantly, P2 is capable of detecting viscosity and ONOO− simultaneously via two well-separated channels (λem = 819/511 nm), which can largely eliminate the influence of fluorescence signal crosstalk. P2 has good specificity for viscosity and ONOO−, as well as brilliant biocompatibility and mitochondria-targeting ability. In addition, P2 can be applied to monitor nystatin and starvation-induced viscosity increase as well as endogenous and exogenous ONOO− alterations in living cells. The probe has been used for in situ fluorescence visualization of viscosity in the inflammatory and diabetic mice. Further, we have realized the simultaneous detection of viscosity and ONOO− during ferroptosis. Hence, P2 might be expected to be applied in researches concerning bifunctional detection of viscosity and ONOO− in some diseases.

PeFUS3 Drives Lateral Root Growth Via Auxin and ABA Signalling Under Drought Stress in Populus.

Changes in root system architecture are vital for plant adaptation to drought stress, yet the underlying molecular mechanisms of this process remain largely elusive. Here, FUSCA3 (FUS3), a B3 domain transcription factor isolated from Populus euphratica, was found to be an important gene of regulating lateral root (LR) development under drought stress. The expression of PeFUS3 was strongly induced by ABA and dehydration treatments. Overexpressing PeFUS3 in poplar 84 K (P. alba × P. glandulosa) positively regulated LR growth and enhanced drought tolerance, while the knockout lines, generated by the CRISPR/Cas9 system, displayed repressed LR growth and weakened drought tolerance. Further investigation demonstrated that PeFUS3 activated the expression of PIN2, PIN6a and AUX1, which were key genes involved in auxin transport, suggesting PeFUS3 modulated LR development under drought stress through auxin signalling. Moreover, PeFUS3 directly upregulated PePYL3 expression, and overexpressing PePYL3 poplar lines exhibited significantly increased drought resistance. In addition, PeABF2, an ABA responsive transcription factor, interacted with PeFUS3 and activated its transcription, indicating PeFUS3 was involved in ABA signalling pathway. Taken together, PeFUS3 is a key regulator, maintaining root growth of poplar by modulating the crosstalk of auxin and ABA signalling under drought stress.

Impact of genomic background and developmental state on signaling pathways and response to therapy in glioblastoma patient-derived cells.

Glioblastoma (GBM) tumors represents diverse genomic epigenomic, and transcriptional landscapes, with significant intratumoral heterogeneity that challenges standard of care treatments involving radiation (RT) and the DNA-alkylating agent temozolomide (TMZ). In this study, we employed targeted proteomics to assess the response of a genomically-diverse panel of GBM patient-derived cancer stem cells (CSCs) to astrocytic differentiation, growth factor withdrawal and traditional high fetal bovine serum culture. Our findings revealed a complex crosstalk and co-activation of key oncogenic signaling in CSCs and diverse patterns of response to these external stimuli. Using RNA sequencing and DNA methylation, we observed common adaptations in response to astrocytic differentiation of CSCs across genomically distinct models, including BMP-Smad pathway activation, reduced cholesterol biosynthesis, and upregulation of extracellular matrix components. Notably, we observed that these differentiated CSC progenies retained a subset of stemness genes and the activation of cell survival pathways. We also examined the impact of differentiation state and genomic background on GBM cell sensitivity and transcriptional response to TMZ and RT. Differentiation of CSCs increased resistance to TMZ but not to RT. While transcriptional responses to these treatments were predominantly regulated by p53 in wild-type p53 GBM cells, its transcriptional activity was modulated by the differentiation status and treatment modality. Both mutant and wild-type p53 models exhibited significant activation of a DNA-damage associated interferon response in CSCs and differentiated cells, suggesting this pathway may play a wider role in GBM response to TMZ and RT. Our integrative analysis of the impact of GBM cell developmental states, in the context of genomic and molecular diversity of patient-derived models, provides valuable insights for pre-clinical studies aimed at optimizing treatment strategies.

Germline mutations in a G protein identify signaling cross-talk in T cells

Humans with monogenic inborn errors responsible for extreme disease phenotypes can reveal essential physiological pathways. We investigated germline mutations in GNAI2 , which encodes G αi2 , a key component in heterotrimeric G protein signal transduction usually thought to regulate adenylyl cyclase–mediated cyclic adenosine monophosphate (cAMP) production. Patients with activating G αi2 mutations had clinical presentations that included impaired immunity. Mutant G αi2 impaired cell migration and augmented responses to T cell receptor (TCR) stimulation. We found that mutant G αi2 influenced TCR signaling by sequestering the guanosine triphosphatase (GTPase)–activating protein RASA2, thereby promoting RAS activation and increasing downstream extracellular signal–regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)–AKT S6 signaling to drive cellular growth and proliferation.

SUMOylation of protein phosphatase 5 regulates phosphatase activity and substrate release

The serine/threonine protein phosphatase 5 (PP5) regulates hormone and stress-induced signaling networks. Unlike other phosphoprotein phosphatases, PP5 contains both regulatory and catalytic domains and is further regulated through post-translational modifications (PTMs). Here we identify that SUMOylation of K430 in the catalytic domain of PP5 regulates phosphatase activity. Additionally, phosphorylation of PP5-T362 is pre-requisite for SUMOylation, suggesting the ordered addition of PTMs regulates PP5 function in cells. Using the glucocorticoid receptor, a well known substrate for PP5, we demonstrate that SUMOylation results in substrate release from PP5. We harness this information to create a non-SUMOylatable K430R mutant as a ‘substrate trap’ and globally identified novel PP5 substrate candidates. Lastly, we generated a consensus dephosphorylation motif using known substrates, and verified its presence in the new candidate substrates. This study unravels the impact of cross talk of SUMOylation and phosphorylation on PP5 phosphatase activity and substrate release in cells.

Reconfigurable mode converter based on a Sb2Se3 phase change material and inverse design

In this paper, we combine the inverse design with a silicon-Sb2Se3 hybrid platform to design an on-chip mode converter that converts basic modes to higher-order modes. Firstly, we present a 1 × 2 mode converter with dimensions of 4.8 × 2.7 µm2 that enables TE0 mode input, TE0 or TE1 output in the C-band (1530 nm to 1565 nm) with an insertion loss (IL) of less than 0.8 dB and a crosstalk (CT) of less than -13 dB. Secondly, the device is extended to a 1 × 3 switchable three-mode converter. Using two controllable phase change regions as drivers, it can flexibly control the switching from TE0 mode input to three modes of TE0, TE1, or TE2 outputs, which enables mode switching and signal routing. The device can be switched between three modes and has broad application potential in broadband optical signal processing for mode division multiplexing systems, as well as optical interconnections. Finally, the device is extended to a 1 × 2 controllable (mode and power) beam splitter, which can control the power ratio between output modes. By modulating the crystallinity of Sb2Se3, the simulation achieves a multilevel switching of 36 levels (> 5-bit). These devices pave the way for high integration densities in future photonic chips.

Stimulating action of sodium nitroprusside and vinasse on salicin and direct regeneration in Salix Safsaf Forssk.

The present study aimed to enhance salicin and direct regeneration inwillow (Salix safsaf Forssk) using the sodium nitroprusside (SNP) regulation of nitric oxide (NO) and vinasse for its nutrition effect in culture medium. Internodes of Salix safsaf were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) (0.25 mg L-1) and different concentrations of SNP (0, 5, 10, 15, and 20 mg L-1) or vinasse (0, 5, 10, and 20%) to examine shoot regeneration, antioxidant defense enzyme activity, total phenolic compounds, flavonoids, and salicine contents. The reported data revealed that application of SNP at15 mg L-1 and vinasse at10% induced asignificant effectin vitro Salix safsaf shoot regeneration. To confirm that, nitric oxide is required for auxin-mediated activation of cell division in a dose-dependent manner. A concentration of 15 mg L-1 SNP promotes regeneration and salicin accumulation (3162.16mg/100g) during signaling action. On the other hand, the cross talk effect of nitric oxide and vinasse combination inSalix safsaf significantly induced a synergistic effect on direct propagation more than vinasse alone. SNP significantly stimulates salicylate accumulation in a dose-dependent manner, but the data on the association of vinasse and SNP on salicylate up-regulation showed a significant reduction in salicin accumulation when SNP was combined with 10% vinasse, which directly affected the signaling action of SNP as secondary product stimulators. Vinasse's phenolic compounds affect directly on thereduction activity ofSNP to suppress its signaling action, or indirectly by inhibiting the sequence cascade of the SNP signaling transduction process to decrease the accumulation of salicin contents. Data confirmed that vinasse andSNP stimulatedtheantioxidant enzymes activity throw quenching thestimulated reactive oxygen species that produced via SNP. Results show that modified media with SNP administration at 15 mg L-1 and the combination of vinasse at 10% and SNP at 15 mg L-1 are recommended for modifying tissue culture media for induced direct regeneration and salicin accumulation in tissue culture applications, which will be very useful for commercial salicin overproduction as a biological active ingredient in willows.

Natural killer cells in neuroblastoma: immunological insights and therapeutic perspectives.

Natural killer (NK) cells have multifaceted roles within the complex tumor milieu. They are pivotal components of innate immunity and shape the dynamic landscape of tumor-immune cell interactions, and thus can be leveraged for use in therapeutic interventions. NK-based immunotherapies have had remarkable success in hematological malignancies, but these therapies are met with many challenges in solid tumors, including neuroblastoma (NB), a childhood tumor arising from the sympathetic nervous system. With a focus on NB, this review outlines the mechanisms employed by NK cells to recognize and eliminate malignant cells, delving into the dynamic relationship between ligand-receptor interactions, cytokines, and other molecules that facilitate the cross talk between NK and NB cells. We discuss the immunomodulatory functions of NK cells and the mechanisms that contribute to loss of this immunosurveillance in NB, with a focus on how this dynamic has been utilized in recent immunotherapy advancements for NB.

Toward Integrated Multifunctional Laser-Induced Graphene-Based Skin-Like Flexible Sensor Systems.

The burgeoning demands for health care and human-machine interfaces call for the next generation of multifunctional integrated sensor systems with facile fabrication processes and reliable performances. Laser-induced graphene (LIG) with highly tunable physical and chemical characteristics plays vital roles in developing versatile skin-like flexible or stretchable sensor systems. This Progress Report presents an in-depth overview of the latest advances in LIG-based techniques in the applications of flexible sensors. First, the merits of the LIG technique are highlighted especially as the building blocks for flexible sensors, followed by the description of various fabrication methods of LIG and its variants. Then, the focus is moved to diverse LIG-based flexible sensors, including physical sensors, chemical sensors, and electrophysiological sensors. Mechanisms and advantages of LIG in these scenarios are described in detail. Furthermore, various representative paradigms of integrated LIG-based sensor systems are presented to show the capabilities of LIG technique for multipurpose applications. The signal cross-talk issues are discussed with possible strategies. The LIG technology with versatile functionalities coupled with other fabrication strategies will enable high-performance integrated sensor systems for next-generation skin electronics.

Relationship of Signaling Pathways between RKIP Expression and the Inhibition of EMT-Inducing Transcription Factors SNAIL1/2, TWIST1/2 and ZEB1/2.

Untreated primary carcinomas often lead to progression, invasion and metastasis, a process that involves the epithelial-to-mesenchymal transition (EMT). Several transcription factors (TFs) mediate the development of EMT, including SNAIL1/SNAIL2, TWIST1/TWIST2 and ZEB1/ZEB2, which are overexpressed in various carcinomas along with the under expression of the metastasis suppressor Raf Kinase Inhibitor Protein (RKIP). Overexpression of RKIP inhibits EMT and the above associated TFs. We, therefore, hypothesized that there are inhibitory cross-talk signaling pathways between RKIP and these TFs. Accordingly, we analyzed the various properties and biomarkers associated with the epithelial and mesenchymal tissues and the various molecular signaling pathways that trigger the EMT phenotype such as the TGF-β, the RTK and the Wnt pathways. We also presented the various functions and the transcriptional, post-transcriptional and epigenetic regulations for the expression of each of the EMT TFs. Likewise, we describe the transcriptional, post-transcriptional and epigenetic regulations of RKIP expression. Various signaling pathways mediated by RKIP, including the Raf/MEK/ERK pathway, inhibit the TFs associated with EMT and the stabilization of epithelial E-Cadherin expression. The inverse relationship between RKIP and the TF expressions and the cross-talks were further analyzed by bioinformatic analysis. High mRNA levels of RKIP correlated negatively with those of SNAIL1, SNAIL2, TWIST1, TWIST2, ZEB1, and ZEB2 in several but not all carcinomas. However, in these carcinomas, high levels of RKIP were associated with good prognosis, whereas high levels of the above transcription factors were associated with poor prognosis. Based on the inverse relationship between RKIP and EMT TFs, it is postulated that the expression level of RKIP in various carcinomas is clinically relevant as both a prognostic and diagnostic biomarker. In addition, targeting RKIP induction by agonists, gene therapy and immunotherapy will result not only in the inhibition of EMT and metastases in carcinomas, but also in the inhibition of tumor growth and reversal of resistance to various therapeutic strategies. However, such targeting strategies must be better investigated as a result of tumor heterogeneities and inherent resistance and should be better adapted as personalized medicine.

Identification of two molecularly and prognostically distinct subtypes in acral melanoma using network prediction method.

Acral melanoma, characterized by its aggressiveness and poor prognosis compared to other melanoma subtypes, poses significant challenges in clinical management. However, the molecular underpinnings driving the biological and clinical features of this disease remain poorly understood. In this study, our aim was to elucidate the molecular landscape and the correlation between subtypes and clinical features of acral melanoma. We conducted comprehensive analyses to dissect the molecular characteristics of acral melanoma, employing a combination of multi-omics data analysis and network-based disease gene prediction algorithms. Single-cell RNA-Seq data were utilized to investigate the contribution of immunocytes to the molecular classification of acral melanoma. Additionally, we used clinical samples to validate the correlation between new subtypes and the prognosis of acral melanoma and the expression of subtype markers and verified the interaction between macrophages and acral melanoma cells at cellular level. Our study reveals the existence of two distinct subtypes of acral melanoma exhibiting marked differences in clinical behaviour, cellular and molecular mechanisms. We identified a robust biomarker panel (EREG, VSIG4, FCGR3A and RAB20) that accurately distinguishes these two subtypes with an impressive AUC of 0.946, validated using clinical samples. Subtype I, characterized by thinner Breslow thickness, demonstrates a favourable prognosis, whereas Subtype II represents a high-risk subtype with a propensity for dermal invasion. Notably, the signature gene EREG of Subtype I is enriched in FCN1+ macrophages, known for promoting inflammatory and immune responses. Conversely, signature genes VSIG4 and FCGR3A of Subtype II are enriched in SPP1+ macrophages, which exhibit significant crosstalk with tumour cells. Our findings significantly enhance the understanding of the molecular landscape of acral melanoma and offer novel insights into its clinical management by identifying distinct subtypes and potential therapeutic targets. The findings have to be confirmed in different cohorts in the future for full validation.

Abstract C045: Targeting metabolic heterogeneity in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the US. This poor prognosis is related to the complex tumor microenvironment and tumor heterogeneity that drives resistance to chemotherapy. Here the heterogeneity of the stromal, immune, and malignant epithelial cell populations enables signaling and metabolic crosstalk mechanisms that drive immune suppression and resistance to therapy. Recently, our group unveiled that multiple distinct metabolic subclasses of cancer cells coexist within individual PDAC tumors. Among these, two PDAC clonal populations can engage in metabolic symbiosis that supports mitochondrial metabolism. One subtype has a constitutively high integrated stress response (ISR), enabling resistance to mitochondrial inhibitors. Further, these cells release asparagine that supports the mitochondrial metabolism of the other subtype that are more sensitive to mitochondrial inhibition. Given these observations, we are developing approaches to disrupt this metabolic symbiosis. Clonal PDAC cells with constitutively active ISR exhibit increased sensitivity to inhibition of the redox activity of Redox factor 1/Apurinic-apyrimidinic endonuclease 1 (Ref-1). Importantly, this can be leveraged to disrupt the support of the mitochondrial metabolism of clonal symbiotic pairs. Moreover, polyclonal PDAC cell lines representative of the heterogeneity seen in PDAC patients show a highly synergistic response to the combination of Ref-1 redox inhibitors with mitochondrial inhibitors. These data suggest this treatment combination will be synergistic in polyclonal tumors that exist in most PDAC patients. Overall, these data have the potential to lead to new avenues to directly target heterogenous populations of cancer cells to treat pancreatic cancer- an urgent clinical need. Citation Format: Taryn Morningstar, Cecily Anaraki, Lorenzo Scipioni, Giulia Tedeschi, Michelle Digman, Aimee Edinger, Claus Jorgensen, Melissa Fishel, Christopher J Halbrook. Targeting metabolic heterogeneity in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C045.