Role Of Signaling Research Articles

Abstract C019: IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver metastases

Abstract Colorectal cancer (CRC) is the third most common cancer and fourth cause of cancer death worldwide. The liver is the most common organ for CRC metastasis, which is a major cause of death for CRC patients. Therefore, a better understanding of mechanisms facilitating CRC liver metastasis is in urgent need. IL27 is a member of IL6/IL12 cytokines superfamily which have a critical role in tumor microenvironment to affect tumorigenesis and metastasis. IL27 is secreted by activated macrophages and dendritic cells, and IL27R is expressed in various immune cells, mediating IL27-dependent pro-inflammatory or anti-inflammatory immune responses. However, the role of myeloid IL27 signaling in CRC-liver metastasis remains unclear. To study the role of IL27R signaling in myeloid cells, we generated Il27ra fl/fl mice and crossed them with LysM cre deleter to obtain LysM cre+ Il27ra f/f mice. Using MC-38 CRC cells portal vein injection model, we found that myeloid IL27Ra deletion leads to increased CRC-liver metastasis accompanied by increase in neutrophils, particularly Ly6G+Cxcr2-CD101- immature neutrophils, in circulation as well as tumors in LysM cre+ Il27ra f/f mice. Single-cell sequencing of tumor-infiltrating immune cells revealed that lack of IL27Ra in myeloid cells promoted neutrophil recruitment and degranulation as well as reactive oxygen species (ROS) and reactive nitrogen species (RNS) production but inhibited neutrophil maturation and production of pro-inflammatory chemokines and cytokines such as CXCL10, CSF1 and TNF. Furthermore, IL27Ra deficient neutrophils displayed heightened inflammatory response when stimulated with LPS in vitro. Collectively, our work reveals novel role of myeloid IL27Ra signaling that inhibits metastatic liver colonization by promoting neutrophil maturation, restricting neutrophil infiltration and degranulation. Citation Format: Jiani Zhu, Zhengzheng Shi, Ekaterina Koltsova. IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver metastases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C019.

Abstract B018: Multifaceted pro-metastatic role of IL-17 signaling in modulating the tumor microenvironment of colorectal cancer

Abstract Colorectal cancer (CRC) ranks second in mortality and advanced CRCs are resistant to current immunotherapies and prone to metastasis, which necessitates research into enhancing innate and adaptive anti-cancer immune responses. Chronic inflammation mediated by cytokines like IL6 and notably, IL17 activates the oncogenic pathways in cancer cells, promoting sporadic and inflammatory CRC. What is unknown, is the ability of cytokines to control tumor microenvironment (TME) via cell type specific mechanisms to increase cancer progression, metastasis and/or therapy resistance. Increased levels of IL17A in CRC portends poor prognosis indicating its potential involvement into metastasis. However, the role of IL17 signaling in TME in the process of CRC progression and metastasis remains enigmatic. We utilized different models of CRC progression and metastasis, as well as variety of genetic mice models and therapeutic interventions. First, using a model of colitis-associated cancer we found that “late” IL17A neutralization decreases tumor burden, possibly acting through regulation of ferroptosis, NK cells mediated cytotoxicity, as well as myeloid cells and chemokine network essential for the control of immunosuppressive TME. Next, models of CRC metastasis, including those based on MC38 cells and APTAK cancerous organoids, showed that IL17A neutralization reduces metastasis growth. Also, FACS analysis revealed that IL17A promotes the recruitment of tumor- associated macrophages and other key myeloid subsets into the metastatic liver environment. Further research, using mice with conditional knockout of IL17RC receptor in myeloid cells (Il17rc f/f -LysMCre) or hepatocytes (Il17rc f/f -AlbCre) also showed significance of IL17 signaling activation in CRC metastasis through two distinct mechanisms. Employing different techniques, from FACS, immunohistochemistry, to RNAseq and scRNAseq data analysis, we observed that local hepatic activation of IL17RC signaling recruits neutrophils and reduces infiltration of cytotoxic CD8+T and NK cells to the metastatic niche supporting tumor growth, while myeloid IL17RC signaling reshapes TME, including macrophages and neutrophils, enhancing CRC metastasis. Our research indicates that IL17 signaling plays a multifaceted pathogenic role in CRC progression by operating in at least several cell types, providing new insights into the basic biology of CRC metastasis and potentially illuminating the design and improvement of CRC treatment strategies. Citation Format: Katarzyna Chojnacka, Katrina Mae Reyes, Hana Tomizawa, Sergei Grivennikov. Multifaceted pro-metastatic role of IL-17 signaling in modulating the tumor microenvironment of colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B018.

Abstract C007: Identifying the role of Interleukin-17 signaling in intestinal stem cells during pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC), the most aggressive type of pancreatic cancer, is predicted to become the second leading cause of cancer related deaths by 2030. Interleukin 17 (IL-17) signaling can promote tumor growth. In pancreatic cancer, IL-17 signaling in cancer cells is capable of triggering the formation of neutrophil extracellular traps (NETs) which is detrimental to the anti-tumor effect of immunotherapy. IL-17 signaling has been shown to have critical roles in maintaining gut homeostasis. Intestinal epithelial cells directly interact with the gut microbiome and are actively involved in infection control, injury repair, immune responses, and the production of antimicrobial peptides and cytokines, and need to be constantly replenished by intestinal stem cells (ISCs). Our lab’s study has previously shown that deletion of Interleukin 17 receptor A (IL-17RA) in the entire gut epithelium induces pro-tumorigenic IL-17 signaling due to the disruption of gut homeostasis, suggesting that immune responses induced by gut IL-17/IL-17RA signaling can affect the behavior of distant tumors. However, the mechanism of IL-17 signaling within specific gut epithelial compartments such as ISCs, enterocytes, secretory cells, etc. and their role in maintaining gut homeostasis and cancer risk are not well-studied until now. Thus, we aimed to identify the importance of IL-17 signaling in ISCs during pancreatic cancer. We hypothesized that disruption of IL-17/IL-17RA signaling within ISCs impacts tumor growth. Our preliminary data shows that IL-17 signaling in enterocytes maintains intestinal homeostasis and disruption of this axis triggers systemic increase in B cells that promotes tumor growth by increasing IL-17 levels in circulation. To identify the function of IL-17/IL-17RA signaling in ISCs, we utilized Leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5), a lineage marker for ISCs, to drive Cre enzyme tissue specific expression to specifically knockout Il17ra in gut ISCs - an inducible transgenic mouse model Il17ra fl/fl ;Lgr5- EGFP-CreERT2 (cKO). We used multiplex staining and imaging to validate the cell type specific loss of IL-17RA expression in tamoxifen treated cKO mice. We used implantable pancreatic tumor models and performed immunoprofiling using flow cytometry. We found that the pancreatic tumor growth was altered by the remote signal from gut ISCs in cKO mice. Furthermore, we performed RNAseq in both tumor and gut tissue which identified that the major changes in gene expression were associated with both innate and adaptive immune pathways, especially B cell activation. We conclude that the IL-17/IL-17RA signaling in gut ISCs changes intestinal immune responses locally that can affect distant tumor immunity. Citation Format: Haoyue Liu, Vidhi Chandra, Le Li, Olivereen Le Roux, Virginia Tahan, Florencia McAllister. Identifying the role of Interleukin-17 signaling in intestinal stem cells during pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C007.

Abstract C037: Chemotherapy causes de novo induction of invasive breast cancer cells

Abstract Metastasis is the leading cause of breast cancer (BC) death, and tumor cells must migrate and invade to metastasize. BC cells that express the actin regulatory protein MenaINV have an enhanced ability to migrate and intravasate within the primary tumor, and extravasate at secondary sites. Though chemotherapy improves patient survival, treatment with paclitaxel, a chemotherapy used for BC, leads to upregulation of MenaINV and an increase in metastasis in mice. MenaINV expression can be induced in BC cells through Notch1 signaling with macrophages, which are often recruited to tumors in response to chemotherapy. MenaINV-expressing cells are also resistant to paclitaxel, begging the question of whether paclitaxel increases MenaINV by de novo induction or by selectively killing non-MenaINV-expressing cells. We hypothesized that paclitaxel causes de novo MenaINV induction by increasing macrophage-tumor cell Notch signaling. Understanding this pro-metastatic effect of chemotherapy is crucial to refining treatment strategies. MMTV-PyMT mice bearing spontaneous mammary tumors were used as a model of BC. Mice were treated with paclitaxel or vehicle every 5 days for a total of 3 treatments. To study the role of macrophages in the paclitaxel-mediated MenaINV increase, in addition to paclitaxel, one cohort of mice was co-administered the macrophage-depleting agent clodronate or vehicle. To study the role of Notch signaling, a second cohort of mice was co-administered the Notch inhibitor DAPT or vehicle. Immunofluorescence staining was used to evaluate tumors for: %MenaINV+ area, proportion of apoptotic cells, macrophage density, and macrophage expression of Notch ligands Jag1 and Jag2. Paclitaxel-treated tumors expressed significantly more MenaINV even when tumor cell death did not increase, indicating that chemotherapy increases MenaINV expression by induction. Both macrophages and Notch signaling were needed for this effect to occur. Interestingly, paclitaxel did not increase macrophage infiltration or macrophage expression of Notch ligands, suggesting that paclitaxel may increase MenaINV by acting on tumor cells to promote Notch signaling. Paclitaxel causes de novo MenaINV induction that is macrophage- and Notch-dependent. Studies aiming to further elucidate the mechanism behind paclitaxel-mediated MenaINV induction are ongoing. These results lay the groundwork for novel microenvironment-based therapies to alleviate the pro-metastatic effects of chemotherapy in BC. Citation Format: Madeline Friedman-DeLuca, George S. Karagiannis, Camille L. Duran, Luis Rivera Sanchez, Prachiben P. Patel, Suryansh Shukla, Nicole D. Barth, Ved P. Sharma, Michael Papanicolaou, John S. Condeelis, Maja H. Oktay, David Entenberg. Chemotherapy causes de novo induction of invasive breast cancer cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C037.

Abstract B011: Sensory neurons regulate intracellular and intercellular mitochondrial dynamics in breast cancer cells

Abstract Crosstalk between cancer and the nervous system regulates tumor progression. These interactions occur at both the local (i.e., within the tumor parenchyma) and systemic (e.g., endocrine signaling) levels. More recent work has determined that cancer cells not only interact with their local environment via secreted molecules, but in some cases, via acquiring proteins or organelles from other cells within the tumor microenvironment (TME). Here, we demonstrate that breast cancer cells acquire mitochondria from neurons. Breast cancer cells with higher metastatic potential acquire more mitochondria in NGF dependent manner compared to the cell line with lower metastatic potential. These results suggest that in addition to their known roles in electrochemical and paracrine signaling, tumor-innervating nerves can also enhance cancer cell fitness via transfer of mitochondria. We are now characterizing the mechanisms underlying this transfer, determining the fate of transferred mitochondria in recipient cells, and defining how transferred mitochondria drive cancer development, progression, and metastasis. Further, sensory neurons at the tumor microenvironment dictate the intracellular mitochondria dynamics affecting morphology and function. The change in mitochondria dynamics enhances cancer cell survival and metastasis, we are uncovering how sensory neuron induced mitochondria dynamics drives tumor progression. Citation Format: Ankit Tiwari, Yue Wu, Jeremy C. Borniger. Sensory neurons regulate intracellular and intercellular mitochondrial dynamics in breast cancer cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B011.

Abstract PR007: Pancreatic cancer cachexia is mediated by tumor-derived PTHrP

Abstract Purpose: Our prior work has established that metastasis is initiated by PTHrP-driven mechanisms in pancreatic ductal adenocarcinoma (PDAC). PTHLH (the gene encoding the PTHrP protein) is directly adjacent to and co-amplified along with KRAS, the major oncogenic driver in PDAC patients. The KRAS-PTHLH amplicon is a marker of the highly aggressive squamous/quasi-mesenchymal/basal-like PDAC patient subtypes, is associated with increases in metastasis and cancer cachexia, and correlates with decreased overall patient survival. We have deleted Pthlh in the autochthonous Kras- and Tp53-driven pancreatic cancer mouse model (i.e. KPC mice) and found that the resulting KPC-Pthlh LoxP mice (herein KPC-PthrpcKO) live nearly twice as long as KPC controls. Intriguingly, recent evidence has emerged for PTHrP’s role in cachexia-associated adipose tissue wasting and we posit that the dramatic survival extension in KPC-PthrpcKO mice may be due to reduced cachexia. Results: In PDAC patients, PTHrP is co-amplified along with KRAS and correlates with significantly decreased overall survival. We generated KPC-PthrpcKO mice and showed that they have reduced tumor burden and dramatically increased overall survival relative to KPC controls. In parallel experiments, we treated mice with an anti-PTHrP neutralizing monoclonal antibody, which similarly extended survival. Upon further analysis, we observed that the overall body condition of KPC-PthrpcKO mice (and anti- PTHrP treated KPC mice) was greatly improved, with less loss of adipose and muscle tissue. Mechanistic studies revealed that tumor cell-derived PTHrP signaling to adipocytes in white adipose tissue depots mediates cachexia. Specifically, we found that adipose tissue wasting and lipolysis were greatly reduced upon deletion or pharmacological inhibition of PTHrP. In the same vein, RNA-seq of cachectic adipose tissue revealed that PTHrP mediates adipose wasting by turning off de novo lipogenesis (DNL), a process critical for the generation of fatty acids in adipocytes. PTHrP binds to its cognate receptor, PTH1R, on adipocytes and blocks fatty acid synthesis by turning off the essential DNL transcription factors CHREBP and SREBP, likely through a PTH1R-PKA-CREB1 signaling axis. Thus, the genetic deletion and pharmacological inhibition of PTHrP in vivo led to a profound reduction in cachexia-related adipose tissue wasting and muscle atrophy. Re-introduction of PTHrP into a PDAC cell line with low cachexia-inducing potential (and low baseline PTHrP) dramatically increased the degree of cachexia observed upon orthotopic implantation, leading to a reduction in overall survival. Therefore, PTHrP is both necessary and sufficient to induce cachexia in pancreatic cancer. Conclusions: This work has demonstrated the importance of the previously unappreciated roles of PTHrP signaling in driving pancreatic cancer cachexia and adipose tissue remodeling, and future studies will look to translate anti-PTHrP therapy into clinical trials. Citation Format: Jason Pitarresi. Pancreatic cancer cachexia is mediated by tumor-derived PTHrP [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr PR007.

Electroacupuncture Regulates Cannabinoid Receptor 1 Expression in a Mouse Fibromyalgia Model: Pharmacological and Chemogenetic Modulation

Fibromyalgia is a chronic illness usually accompanied by long-lasting, general pain throughout the body, often accompanied by anxiety, depression, fatigue, and sleep disruption. Meanwhile, doctors and scientists have not entirely discovered detailed mechanisms; patients always have an exaggerated sensation to pervasive pain without satisfied medical service. Given the lack of knowledge on its underlying mechanism, current treatments aim to provide pain and/or symptom relief. The present study aimed to clarify the role of cannabinoid receptor 1 (CB1) signaling in a mouse fibromyalgia pain model. To develop the mouse fibromyalgia model, mice were subjected to intermittent cold stress (ICS). Our results indicated that mechanical (2.09 ± 0.09 g) and thermal hyperalgesia (4.77 ± 0.29 s), which were evaluated by von Frey and Hargraves’ tests, were induced by ICS, suggesting successful modeling. The hurting replies were then provoked by electroacupuncture (EA) but not for sham EA mice. Further, in a Western blot analysis, we found significantly decreased CB1 protein levels in the thalamus, somatosensory cortex, and anterior cingulate cortex. In addition, the levels of pain-related protein kinases and transcription factor were increased. Treatment with EA reliably increased CB1 expression in various brain regions sequentially alleviated by nociceptive mediators. Furthermore, the administration of a CB1 agonist significantly attenuated fibromyalgia pain, reversed EA analgesia by the CB1 antagonist, and further reversed the chemogenetic inhibition of SSC. Our innovative findings evidence the role of CB1 signaling in the interaction of EA and fibromyalgia, suggesting its potential for clinical trials and as a treatment target.

Diverse roles of phytohormonal signaling in modulating plant-virus interaction.

Virus infection brings about changes in the transcriptome, proteome and metabolome status of the infected plant wherein substantial alterations in the abundance of phytohormones and associated components involved in their signaling pathways have been observed. In the recent years, extensive research in the field of plant virology has showcased the undisputable significance of phytohormone signaling during plant-virus interactions. Apart from acting as growth regulators, phytohormones elicit robust immune response, which restricts the viral multiplication within the plant as well as its propagation by vector. Interestingly, these pathways have been shown to not only act as isolated mechanisms but as complex intertwined regulatory cascades where, the cross-talk among different phytohormones and with other antiviral pathways takes place during plant-virus interplay. Viruses cleverly disrupt phytohormone homeostasis via their multifunctional effectors that seems to be smart approach adopted by viruses to circumvent phytohormone-mediated plant immune responses. In this review, we summarize the current understanding of role of phytohormone signaling pathways during plant-virus interaction in activating antiviral immune responses of plant and also, how viruses exploit these signaling pathways favoring their pathogenesis.

Revisiting the Role of Atmospheric Initial Signals in Predicting ENSO

Abstract El Niño–Southern Oscillation (ENSO) provides an important source of global seasonal–interannual predictability, while its prediction encounters bottlenecks. Besides the slow-varying air–sea feedbacks, high-frequency atmospheric signals (HFASs) act on ENSO evolution. This study revisits the role of atmospheric initial signals in ENSO prediction using an atmosphere–ocean coupled model. Two sets of sensitivity hindcasts are conducted. One utilizes a pure sea surface temperature (SST) nudging for initialization so that no observed atmospheric internal signal is assimilated. The other applies a combination of the SST nudging and spectral nudging of JRA-55 reanalysis, which not only assimilates the observed atmospheric states and hence realizes skillful predictions of HFAS at the initial stage but also improves the oceanic initial conditions (ICs), especially around the thermocline. Unexpectedly, the better atmosphere–ocean ICs neither improve ENSO prediction nor overcome the spring prediction barrier. Further analysis of Bjerknes stability index suggests that underestimated negative feedbacks and insufficient responses of ocean currents and thermocline slope to atmospheric internal winds may account for the failure. Nevertheless, assimilating the atmospheric information partly improves the prediction of El Niño onset, especially for two recent extreme cases (i.e., 1997/98 and 2015/16). This improvement is associated with better representations of initial westerly wind bursts (WWBs) that excite subsequent downwelling equatorial Kelvin waves. However, due to unpredictable WWBs and underestimated wind response to the SST warming owing to the cold tongue biases in boreal summer, the zonal advective feedbacks are underestimated and thus further development of El Niño cannot be well predicted. This study suggests the importance of initial atmospheric signals despite the limitation, prompting further efforts to improve model physics.

Pathophysiological role of high mobility group box-1 signaling in neurodegenerative diseases.

Nucleocytoplasmic translocation of HMGB1 (high mobility group box-1) plays a significant role in disease progression. Several methods contribute to the translocation of HMGB1 from the nucleus to the cytoplasm, including inflammasome activation, TNF-α signaling, CRM1-mediated transport, reactive oxygen species (ROS), JAK/STAT pathway, RIP3-mediated p53 involvement, XPO-1-mediated transport, and calcium-dependent mechanisms. Due to its diverse functions at various subcellular locations, HMGB1 has been identified as a crucial factor in several Central Nervous System (CNS) disorders, including Huntington's disease (HD), Parkinson's disease (PD), and Alzheimer's disease (AD). HMGB1 displays a wide array of roles in the extracellular environment as it interacts with several receptors, including CXCR4, TLR2, TLR4, TLR8, and RAGE, by engaging in these connections, HMGB1 can effectively regulate subsequent signaling pathways, hence exerting an impact on the progression of brain disorders through neuroinflammation. Therefore, focusing on treating neuroinflammation could offer a common therapeutic strategy for several disorders. The objective of the current literature is to demonstrate the pathological role of HMGB1 in various neurological disorders. This review also offers insights into numerous therapeutic targets that promise to advance multiple treatments intended to alleviate brain illnesses.

SGLT2 inhibition improves coronary flow velocity reserve and contractility: role of glucagon signaling.

SGLT2 inhibitors, a T2DM medication to lower blood glucose, markedly improve cardiovascular outcomes but the underlying mechanism(s) are not fully understood. SGLT2i's produce a unique metabolic pattern by lowering blood glucose without increasing insulin while increasing ketone body and glucagon levels and reducing body weight. We tested if glucagon signaling contributes to SGLT2i induced improvement in CV function. Cardiac contractility and coronary flow velocity reserve (CFVR) were monitored in ob/ob mice and rhesus monkeys with metabolic syndrome using echocardiography. Metabolic status was characterized by measuring blood ketone levels, glucose tolerance during glucose challenge and Arg and ADMA levels were measured. Baysian models were developed to analyse the data. Dapagliflozin improved CFVR and contractility, co-application of a glucagon receptor inhibitor (GcgRi) blunted the effect on CFVR but not contractility. Dapagliflozin increased the Arg/ADMA ratio and ketone levels and co-treatment with GcgRi blunted only the Dapagliflozin induced increase in Arg/ADMA ratio but not ketone levels. Since GcgRi co-treatment only reduced the Arg/ADMA increase we hypothesize that dapagliflozin via a glucagon-signaling dependent pathway improves vascular function through the NO-signaling pathway leading to improved vascular function. Increase in ketone levels might be a contributing factor in SGLT2i induced contractility increase and does not require glucagon signaling.

Targeting the mTOR-Autophagy Axis: Unveiling Therapeutic Potentials in Osteoporosis

Osteoporosis (OP) is a widespread age-related disorder marked by decreased bone density and increased fracture risk, presenting a significant public health challenge. Central to the development and progression of OP is the dysregulation of the mechanistic target of the rapamycin (mTOR)-signaling pathway, which plays a critical role in cellular processes including autophagy, growth, and proliferation. The mTOR-autophagy axis is emerging as a promising therapeutic target due to its regulatory capacity in bone metabolism and homeostasis. This review aims to (1) elucidate the role of mTOR signaling in bone metabolism and its dysregulation in OP, (2) explore the interplay between mTOR and autophagy in the context of bone cell activity, and (3) assess the therapeutic potential of targeting the mTOR pathway with modulators as innovative strategies for OP treatment. By examining the interactions among autophagy, mTOR, and OP, including insights from various types of OP and the impact on different bone cells, this review underscores the complexity of mTOR’s role in bone health. Despite advances, significant gaps remain in understanding the detailed mechanisms of mTOR’s effects on autophagy and bone cell function, highlighting the need for comprehensive clinical trials to establish the efficacy and safety of mTOR inhibitors in OP management. Future research directions include clarifying mTOR’s molecular interactions with bone metabolism and investigating the combined benefits of mTOR modulation with other therapeutic approaches. Addressing these challenges is crucial for developing more effective treatments and improving outcomes for individuals with OP, thereby unveiling the therapeutic potentials of targeting the mTOR-autophagy axis in this prevalent disease.

The Role of SMAD7 in the Epigenetic Regulation of TGF-β Targets in the Metastasis of Ovarian Cancer.

The role of TGF-β signaling in the epigenetic modifications involved in ovarian cancer is not fully understood. This study investigated the relationship between TGF-β signaling, epigenetic modifications, and cellular behaviors in ovarian cancer. We found that E-cadherin, a key cell adhesion molecule, underwent epigenetic silencing via promoter DNA hypermethylation in ovarian cancer cell lines and that this was accompanied by the upregulation of vimentin, which is indicative of a mesenchymal and invasive phenotype. DNA-demethylating agents restored E-cadherin expression, which suggests that TGF-β signaling mediates this epigenetic silencing. Overexpression of SMAD7, an inhibitory component of TGF-β signaling, reversed E-cadherin silencing, which suggests a role of SMAD7 in modulating the epigenetic status. Functionally, SMAD7 overexpression inhibited the migration and invasion in ovarian cancer cells, which suggests its therapeutic potential for suppressing metastasis. Clinically, ovarian cancer patients with high SMAD7 expression had significantly longer disease-free survival. Mechanistically, SMAD7 overexpression decreased the acetylation of H3K9 and the binding of the transcriptional repressor TWIST1 at the E-cadherin promoter, which promoted its demethylation and reactivation. Disruption of TGF-β signaling upregulated SMAD4 target genes, which are silenced by epigenetic mechanisms, a finding that suggests broader therapeutic implications. Overall, our results provide insights into the role of TGF-β-mediated epigenetic regulation in ovarian cancer metastasis and underscore the therapeutic potential of targeting TGF-β signaling and its downstream effectors. Further research is needed to elucidate the underlying mechanisms and validate these therapeutic strategies.

The intraflagellar transport cycle.

Primary and motile cilia are eukaryotic organelles that perform crucial roles in cellular signalling and motility. Intraflagellar transport (IFT) contributes to the formation of the highly specialized ciliary proteome by active and selective transport of soluble and membrane proteins into and out of cilia. IFT is performed by the IFT-A and IFT-B protein complexes, which together link cargoes to the microtubule motors kinesin and dynein. In this Review, we discuss recent structural and mechanistic insights on how the IFT complexes are first recruited to the base of the cilium, how they polymerize into an anterograde IFT train, and how this complex imports cargoes from the cytoplasm. We will describe insights into how kinesin-driven anterograde trains are carried to the ciliary tip, where they are remodelled into dynein-driven retrograde trains for cargo export. We will also present how the interplay between IFT-A and IFT-B complexes, motor proteins and cargo adaptors is regulated for bidirectional ciliary transport.

Abstract B021: tRNA fragments extracted from patient plasma extra cellular vesicles display potential as biomarkers for high-grade glioma

Abstract Transfer RNA (tRNA) are non-coding RNAs that bring amino acids to ribosomes during translation. Recent studies have shown that cleaved fragments derived from tRNA (tRFs) serve regulatory roles in epigenetics, signaling, transcription, and translation. tRFs can be released from cells and can be found in extracellular vesicles to perform some aspects of paracrine signaling. Utilizing high throughput small RNA sequencing, we have identified over 750 uniquely or multi-mapped (6.9% of total sRNA mapped reads) tRFs in extracellular vesicles of high-grade glioma (IDH-WT) patient plasma. By performing differential expression analysis, we identified 6 upregulated tRFs and 36 downregulated tRFs between high-grade glioma plasma EVs and non-cancer controls (n = 14, FDR<0.05). Differentially expressed tRFs (all 42) were further analyzed using bioinformatic techniques (RNAhybrid and IntaRNA) to predict potential gene targets. By performing gene ontology analysis (ShinyGO) we found that 70 of 75 genes related to glioma formation were identified as potential gene targets, indicating a possible role of tRFs in the regulation and formation of gliomas. A number of differentially expressed tRFs were predicted to target cancer-related genes including Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT-1). This analysis demonstrates that tRFs may serve as important biomarkers and regulators with therapeutic potential in the future Citation Format: Thomson R Phinney, Ali Alwadei, Gabriel Gabriel Wajnberg, Jae Han, Simi Chacko, Kathleen Attwood, Jeremy Roy, Adriennne Weeks. tRNA fragments extracted from patient plasma extra cellular vesicles display potential as biomarkers for high-grade glioma [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B021.

Role of glutamatergic signaling in the acquisition and expression of learned sugar preferences in C57BL/6 mice.

C57BL/6 (B6) mice learn to prefer glucose or sucrose to initially isopreferred or even more preferred nonnutritive sweeteners presumably due to the postoral appetite stimulating (appetition) actions of glucose. Recent evidence indicates that specific duodenal neuropod cells transmit the glucose appetition signal to the brain via glutamatergic synaptic connections with vagal afferents. The present study found that intraperitoneal pretreatment with a glutamatergic receptor antagonist cocktail (kynurenic acid (KA)/D-2-amino-3-phosphonopentanoic acid (AP3)) in B6 mice did not block the expression of their learned preference for 8% glucose solution over an initially-preferred 0.1% sucralose + 0.1% saccharin solution. However, acquisition of the glucose preference was blocked by drug treatment during 1-h training sessions with the two sweeteners. Systemic KA/AP3 injections also did not block the expression of the learned preference for a 10.6% sucrose solution over a 0.6% sucralose solution. Drug effects on the acquisition of the sucrose preference were not determined because sucrose, unlike glucose conditioning, required 24-h training trials. The findings that the 1-h training regimen conditioned 8% glucose, but not 10.6% sucrose, preferences suggest that glucose has more potent appetition actions. This was confirmed by the finding that B6 mice learned to prefer 10.6% glucose to 10.6% sucrose after 1-h or 24-h training despite an initial strong sucrose preference. This action can be explained by 10.6% sucrose's digestion in the gut to glucose and fructose with only glucose activating the gut-brain appetition pathway.

Tumor microenvironment and cancer metastasis: molecular mechanisms and therapeutic implications

The tumor microenvironment (TME) plays a crucial role in cancer development and metastasis. This review summarizes the current research on how the TME promotes metastasis through molecular pathways, focusing on key components, such as cancer-associated fibroblasts, immune cells, endothelial cells, cytokines, and the extracellular matrix. Significant findings have highlighted that alterations in cellular communication within the TME enable tumor cells to evade immune surveillance, survive, and invade other tissues. This review highlights the roles of TGF-β and VEGF signaling in promoting angiogenesis and extracellular matrix remodeling, which facilitate metastasis. Additionally, we explored how metabolic reprogramming of tumor and stromal cells, influenced by nutrient availability in the TME, drives cancer progression. This study also evaluated the therapeutic strategies targeting these interactions to disrupt metastasis. By providing a multidisciplinary perspective, this study suggests that understanding the molecular basis of the TME can lead to more effective cancer therapies and identify potential avenues for future research. Future research on the TME should prioritize unraveling the molecular and cellular interactions within this complex environment, which could lead to novel therapeutic strategies and personalized cancer treatments. Moreover, advancements in technologies such as single-cell analysis, spatial transcriptomics, and epigenetic profiling offer promising avenues for identifying new therapeutic targets and improving the efficacy of immunotherapies, particularly in the context of metastasis.

Human ITGAV variants are associated with immune dysregulation, brain abnormalities, and colitis.

Integrin heterodimers containing an Integrin alpha V subunit are essential for development and play critical roles in cell adhesion and signaling. We identified biallelic variants in the gene coding for Integrin alpha V (ITGAV) in three independent families (two patients and four fetuses) that either caused abnormal mRNA and the loss of functional protein or caused mistargeting of the integrin. This led to eye and brain abnormalities, inflammatory bowel disease, immune dysregulation, and other developmental issues. Mechanistically, the reduction of functional Integrin αV resulted in the dysregulation of several pathways including TGF-β-dependent signaling and αVβ3-regulated immune signaling. These effects were confirmed using immunostaining, RNA sequencing, and functional studies in patient-derived cells. The genetic deletion of itgav in zebrafish recapitulated patient phenotypes including retinal and brain defects and the loss of microglia in early development as well as colitis in juvenile zebrafish with reduced SMAD3 expression and transcriptional regulation. Taken together, the ITGAV variants identified in this report caused a previously unknown human disease characterized by brain and developmental defects in the case of complete loss-of-function and atopy, neurodevelopmental defects, and colitis in cases of incomplete loss-of-function.

TMIC-61. DEVELOPMENT OF A NOVEL NOTCH-TARGETING ONCOLYTIC HSV FOR GBM TUMORS

Abstract Glioblastoma (GBM) is the most aggressive brain malignancy, which despite continuing worldwide efforts to develop new therapies, remains a deadly disease with limited treatment options. The NOTCH signaling pathway is often hyperactive in GBM tumors, and its activity contributes to tumor progression and resistance to treatment. The role of NOTCH signaling in tumor growth and resistance is well studied, but the significance of this pathway for immunotherapy of GBM is not very well understood. We have recently shown that NOTCH activation following virotherapy contributes to tumor regrowth and induces recruitment of monocytic MDSC cells into the tumor, which limit optimal immune activation to kill tumor cells. For this study, we have discovered a NOTCH interfering intracellular ligand (NIIL) that blocks NOTCH activation from inside glioma cells. RNA sequencing shows the expression of NIIL downregulates NOTCH signaling in vitro. To evaluate the effect of NIIL on virotherapy, we generated an oncolytic herpes simplex virus (oHSV) that also encodes for NIIL. This virus showed a slower spread in vitro but improved therapeutic efficacy in vivo in multiple models of intracranial tumors. In immune competent mice there was a significant improvement in the survival of mice treated with the NIIL-encoding virus, with a fraction of mice showing a complete response after a single treatment. Single-cell RNA sequencing analysis of immune infiltrates is ongoing to understand how NIIL impacts tumor microenvironment and anti-tumor immune therapy.

IMMU-59. AN IMMUNOSUPPRESSIVE PROGRAM ENCOMPASSING MULTIPLE IMMUNE CELL TYPES IN GBM TYPIFIED BY NOVEL MARKER LRRC25 ASSOCIATED WITH TYROBP SIGNALING

Abstract Immunosuppression in glioblastoma is a powerful impediment to effective immunotherapy. We used maximal tumor sampling and genome-wide coexpression analysis of RNA sequencing, on 69 samples from 8 patients, to identify a module of 270 genes marked by LRRC25, determined by top fidelity score, that covaries with many immunosuppressive molecules. An immunosuppressive module was independently derived from an expanded cohort of 319 samples from 28 GBM also marked by LRRC25 by top fidelity score. Within the gene module, we observed strong co-variation of markers for monocytes, neutrophils, and NK cells with LRRC25. In published single-cell RNA-seq from glioma, we determined that LRRC25 is expressed by neutrophils and myeloid cells while absent from NK-cells. LRRC25 is also constitutively expressed in monocytes and neutrophils while being upregulated by microglia and DCs in the tumor core and necrotic regions. In addition to covariation with multiple cell-type specific markers we also discovered that LRRC25 expression is tightly associated with several members of the TYROBP causal signaling network in microglia. Thus, LRRC25 may play a novel role in TYROBP signaling which may, in turn, represent a novel mechanism of NK cell and neutrophil immunosuppression in glioma. We confirmed LRRC25 RNA expression in patient samples by RNAscope co-stained with an anti-CD163 antibody indicating myeloid expression, as well as tumor cell expression determined by histopathology. Although LRRC25 is known to mediate IFN and NFKb signaling in myeloid cells in-vitro, its function in glioma remains understudied. While significant efforts have focused on mechanisms of myeloid to T-cell immunosuppression, less focus has been given to mechanisms of myeloid to NK-cell and neutrophil immunosuppression, despite the fact they exist at levels comparable to T-cells in the tumor microenvironment. This work will be followed up with antibody validation as well as genetic manipulation of LRRC25 in-vitro and in-vivo.