Growth Factor Receptor Signaling Research Articles

Abstract 6584: Aberrant TRIM7 expression potentiates RACO-1 mediated proliferation and dysregulated interferon responsiveness in the setting of anti-PD-1 acquired resistance in cancer

Abstract While checkpoint inhibitor treatment has extended the survival of many cancer patients, most initial responders will later develop disease progression through a variety of poorly understood acquired resistance mechanisms (CPI-AR). One such recently described mechanism involves the transcriptional hyperactivation of genes associated with interferon (IFN) signaling, JAK/STAT, and antigen processing/presentation pathways. Aberrant IFN regulation in the setting of AR suggests that tumor cell intrinsic mechanisms have conferred a growth advantage despite the presence of immune-mediated pressure unleashed by PD-1/L1 antibody blockade. Analysis of transcripts progressively upregulated during acquisition of AR in vivo and transcripts upregulated by IFN exposure of isolated AR cell lines in vitro identified the E3 ubiquitin ligase TRIM7 as a candidate mediator of the AR phenotype. A specific pocket on the PRY/SPRY domain of TRIM7 has been shown to bind viral peptides, resulting in ubiquitination and degradation as a mechanism to mitigate viral propagation. Here we describe the evaluation of small molecule inhibitors (SMI) designed to the TRIM7 PRY/SPRY viral-pocket domain, where binding specificity was confirmed using mass spec analysis. These SMI competitively inhibited TRIM7 mediated stabilization of RACO-1, resulting in decreased cancer cell proliferation which was associated with altered c-Jun/AP-1 transcription. TRIM7 SMI also disrupted STING and MAVS ubiquitination and restored IFN responsiveness and sensitivity to PD-1 inhibitor treatment. Finally, given the position of TRIM7 downstream of growth factor receptor and kras signaling, combination of TRIM7 inhibitors with kras, braf, and/or MEK inhibitors was shown to additively suppress proliferation of tumor cells with kras mutations. These results provide evidence that upregulation of TRIM7 mediates both a pro-proliferative and IFN resistant phenotype in the setting of CPI-AR, and that inhibition of TRIM7 with small molecule inhibitors may prevent or reverse AR to PD-1/L1 blockade. Citation Format: Thuy-Ai Tran Nguyen, Marc Morra, Kevin Li, Ulhas Bhatt, Joseph Mwangi, Yisel Rivera-Molina, Nathan Oien, Julio Medina, Taylor H. Schreiber, George Fromm. Aberrant TRIM7 expression potentiates RACO-1 mediated proliferation and dysregulated interferon responsiveness in the setting of anti-PD-1 acquired resistance in 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 6584.

Abstract 5799: Novel nanoparticle technology targets the delivery of polyIC to EGFR overexpressing cancers and induces a multimodal anti-tumor response

Abstract Aberrant activation of epidermal growth factor receptor (EGFR) signaling pathways is associated with tumor growth and progression. EGFR overexpression occurs in various types of solid cancers and correlates with poor outcome. Unfortunately, the clinical benefit from EGFR-targeted therapies is usually short-lived, due to the development of resistance. TargImmune has developed first-in-class Targeted Apoptotic Immunomodulators (TAIMs), which harness the body’s anti-viral responses to treat solid tumors. Our novel nanoparticle platform technology, Ta:RNA , selectively delivers synthetic dsRNA, polyinosinic:polycytidylic acid (polyIC) to tumor cells that overexpress a target receptor. PolyIC and other pattern recognition receptor (PRR) agonists have been used as adjuvants or for intratumoral administration but have limited efficacy as single agents. TargImmune’s platform allows systemic delivery of dsRNA, tailoring the nanoparticles to various solid cancers by simply changing the targeting moiety. Here we describe EGFR-Ta:RNA, which is targeted to tumors that overexpress EGFR. EGFR-Ta:RNA does not inhibit EGFR per se, and therefore activation of alternative or downstream oncogenes is not expected to cause resistance. The mechanism of action of EGFR-targeted Ta:RNA nanoparticles was extensively studied in vitro and in vivo, using confocal imaging, large-scale RNA sequencing studies, Western blot analysis and ELISA assays. In vitro, EGFR-Ta:RNA potency and selectivity were established by comparing cells with high receptor and low receptor expression. Imaging studies showed that the nanoparticles are internalized selectively into EGFR-overexpressing cancer cells by receptor-mediated endocytosis. RNAseq studies revealed: (i) a common transcriptional signature in EGFR-Ta:RNA-treated tumours and cancer cells; (ii) enrichment in pathways related to anti-viral response, inflammation, type I interferon signaling, and NFΚB signaling; (iii) enrichment in genes coding for cytokines. Western blot analysis and ELISA assays confirmed that the mechanism of action of EGFR-Ta:RNA is mediated via the induction of PRR downstream signaling, which results in cytokine secretion, apoptosis and immune cell activation. The efficacy of EGFR-Ta:RNA was demonstrated in multiple animal models, including both xenograft and immunocompetent models. The pharmacodynamic effect, exemplified by target engagement and activation of PRR signaling in tumors, was verified in vivo. In conclusion, TargImmune’s EGFR-Ta:RNA nanoparticles deliver polyIC in a tumor-targeted manner to evoke PRR signaling, inducing targeted tumor cell apoptosis as well as immune cell recruitment and activation against the heterogenous tumor. EGFR-Ta:RNA represents a novel, multimodal treatment approach for EGFR overexpressing cancers. Citation Format: Derrick Broka, Caroline De Feyter, Shoshana Klein, Meera Saxena, Joerg Schreiber, Alexei Shir, Michal Skowicki, Yaakov Benenson, Alexander Levitzki, Cornelia G. Palivan, Esteban Pombo-Villar, Babette Schade, Maya Zigler. Novel nanoparticle technology targets the delivery of polyIC to EGFR overexpressing cancers and induces a multimodal anti-tumor response [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 5799.

Abstract 2998: Regulation of epidermal growth factor receptor signaling by BRCA1-microRNA 146a network

Abstract Inherited defects in the breast cancer susceptibility gene, BRCA1 are associated with an increased risk for hereditary breast, ovarian, and other cancers. BRCA1-associated basal like breast cancers (BLBCs) are high-grade ductal carcinomas that do not express ER, PR or HER2, but frequently overexpress epidermal growth factor receptor (EGFR/ErbB1/HER1). The EGFR-driven signaling network plays a pivotal role in BLBC pathogenesis. EGFR overexpression is associated with tumor progression and metastasis, resistance to radiation and chemotherapy, and poor prognosis. Growth factor receptors are regulated by multiple miRNAs, each having many targets, coordinately controlling the complex pathways of downstream signaling. We have previously reported a post-transcriptional mechanism by which BRCA1 regulates EGFR expression through the induction of miR-146a and provided a rationale for the development of miR-146a based therapeutic strategies. In addition, we have shown that BRCA1 also exerts regulatory control over dozens of important miRNAs that appear to play a critical role in breast neoplasia. From TCGA analysis, we show that low expression of these miRNAs is associated with distinctively poor overall survival of TNBC patients. Using miR-146a loss or gain of function experiments in vitro, we show that BRCA1 and miR-146a regulate EGFR signaling, stemness, epithelial-to-mesenchymal transition (EMT), extracellular matrix (ECM) remodeling and chemoresistance. Using in vivo mouse models, we demonstrate that miR-146a overexpression delays tumor formation leading to better overall survival. BLBC unlike the other subtypes, lacks targeted therapy approaches making cytotoxic chemotherapy essentially the only option for treatment. Though EGFR inhibitors have been used to treat other cancers, clinical trials for breast cancer have so far been unsuccessful due to poor response rates. Since one miRNA can target multiple genes and regulate multiple signaling pathways, our study provides evidence to suggest that restoring miR-146a could suppress EGFR-RAS-MEK signaling and the other compensatory pathways, providing a targeted therapeutic option for BRCA1 associated BLBC. Citation Format: Easwari Kumaraswamy, Raeann M. Koren Shimak, Sumedha Gunewardena, Karen L. Wendt, Dani Alexander, Stacey L. Hembruff, Roy A. Jensen. Regulation of epidermal growth factor receptor signaling by BRCA1-microRNA 146a network [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 2998.

Insights into the Overcoming EGFRDel19/T790M/C797S Mutation: A Perspective on the 2-Aryl-4-aminothienopyrimidine Backbone.

The epithelial growth factor receptor (EGFR) signaling pathway has been proposed to benefit non-small cell lung cancer (NSCLC) treatment. In this manuscript, we investigated the modification of 2-aryl-4-aminoquinazoline, the classical backbone of the fourth-generation EGFR inhibitors, in addition to obtaining a series of novel 2-aryl-4-aminothienopyrimidine derivatives (A1~A45), we also gained further understanding of the modification of this framework. Derivatives were tested for cytotoxicity against cancer cell lines (cervical cancer cell line Hela, lung cancer cell lines A549, H1975, and PC-9, Ba/F3-EGFRDel19/T790M/C797S cells, and human normal hepatocytes LO2) as well as for the derivative's inhibitory activity against EGFRWT, EGFRL858R/T790M, and EGFRDel19/T790M/C797S kinase inhibitory activities. The results showed that most of the target compounds showed moderate to excellent activity against one or more cancer cell lines. Among them, the antitumor activity (IC50) of the most promising A9 against A549 and H1975 cell lines was 0.77±0.08 μM, 6.90±0.83 μM, respectively. At concentration of 10 μM, A9 can be employed as the fourth-generation of EGFR inhibitors with the ability to overcome the C797S drug resistance since it can suppress EGFRDel19/T790M/C797S cells and kinase by 98.90 % and 85.88 %, respectively. Moreover, the tumor-bearing nude mice experiment further shows that A9 can significantly inhibit the growth of tumor in vivo, with the tumor inhibition rate (TIR) of 55.92 %, which was equivalent to the positive group. After that, from the result of HE staining experiment and blood biochemical analysis experiment, A9 show low toxicity and good safety, which is worthy of further research and development.

Mechanism of ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix regulates HIF-1α signaling pathway mediated by renal hypoxia to ameliorate renal fibrosis in DKD rats

This study explored the mechanism of the ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix in ameliorating renal fibrosis in the rat model of diabetic kidney disease(DKD) based on the expression of hypoxia-inducible factor-1α(HIF-1α)/vascular endothelial growth factor(VEGF) and HIF-1α/platelet-derived growth factor(PDGF)/platelet-derived growth factor receptor(PDGFR) signaling pathways in the DKD rats. After 1 week of adaptive feeding, 50 male SPF-grade Wistar rats were randomized into a blank group(n=7) and a modeling group. After 24 h of fasting, the rats in the modeling group were subjected to intraperitoneal injection of streptozocin and fed with a high-sugar and high-fat diet to establish a DKD model. After modeling, the rats were randomly assigned into model(n=7), low-dose ultrafiltration extract(n=7), medium-dose ultrafiltration extract(n=7), irbesartan(n=8), and high-dose ultrafiltration extract(n=8) groups. After intervention by corresponding drugs for 12 weeks, the general conditions of the rats were observed. The body weights and blood glucose levels of the rats were measured weekly, and the 24 h urinary protein(24hUP) was measured at the 6th and 12th weeks of drug administration. After the last drug administration, the renal function indicators were determined. Masson staining was employed to observe the pathological changes of the renal tissue. The expression of prolyl hydroxylase domain 2(PHD2) and HIF-1α in the renal tissue was detected by immunohistochemistry(IHC). Real-time qPCR was employed to determine the mRNA levels of PHD2, VEGF, PDGF, and PDGFR in the renal tissue. Western blot was employed to determine the protein levels of HIF-1α, VEGF, PDGF, and PDGFR in the renal tissue. The results showed that compared with the model group, drug administration lowered the levels of glycosylated serum protein(GSP), aerum creatinine(Scr), and blood urea nitrogen(BUN) in a dose-dependent manner(P<0.05 or P<0.01) and mitigated the pathological changes in the renal tissue. Furthermore, drug administration up-regulated mRNA level of PHD2(P<0.05 or P<0.01), down-regulated the mRNA levels of VEGF, PDGF, and PDGFR(P<0.05 or P<0.01) and the protein levels of HIF-1α, VEGF, PDGF, and PDGFR(P<0.01) in the renal tissue, and increased the rate of PHD2-positive cells(P<0.01). In conclusion, the ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix effectively alleviated the renal fibrosis in DKD rats by inhibiting the expression of key proteins in the HIF-1α signaling pathway mediated by renal hypoxia and reducing extracellular matrix(ECM) deposition.

Critical Role of CD55 in Controlling Wound Healing.

How reparative processes are coordinated following injury is incompletely understood. In recent studies, we showed that autocrine C3a and C5a receptor (C3ar1 and C5ar1) G protein-coupled receptor signaling plays an obligate role in vascular endothelial growth factor receptor 2 growth signaling in vascular endothelial cells. We documented the same interconnection for platelet-derived growth factor receptor growth signaling in smooth muscle cells, epidermal growth factor receptor growth signaling in epidermal cells, and fibroblast growth factor receptor signaling in fibroblasts, indicative of a generalized cell growth regulatory mechanism. In this study, we examined one physiological consequence of this signaling circuit. We found that disabling CD55 (also known as decay accelerating factor), which lifts restraint on autocrine C3ar1/C5ar1 signaling, concomitantly augments the growth of each cell type. The mechanism is heightened C3ar1/C5ar1 signaling resulting from the loss of CD55's restraint jointly potentiating growth factor production by each cell type. Examination of the effect of lifted CD55 restraint in four types of injury (burn, corneal denudation, ear lobe puncture, and reengraftment of autologous skin) showed that disabled CD55 function robustly accelerated healing in all cases, whereas disabled C3ar1/C5ar1 signaling universally retarded it. In wild-type mice with burns or injured corneas, applying a mouse anti-mouse CD55 blocking Ab (against CD55's active site) to wounds accelerated the healing rate by 40-70%. To our knowledge, these results provide new insights into mechanisms that underlie wound repair and open up a new tool for accelerating healing.

ELK1/MTOR/S6K1 Pathway Contributes to Acquired Resistance to Gefitinib in Non-Small Cell Lung Cancer.

The development of acquired resistance to small molecule tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor (EGFR) signaling has hindered their efficacy in treating non-small cell lung cancer (NSCLC) patients. Our previous study showed that constitutive activation of the 70 kDa ribosomal protein S6 kinase 1 (S6K1) contributes to the acquired resistance to EGFR-TKIs in NSCLC cell lines and xenograft tumors in nude mice. However, the regulatory mechanisms underlying S6K1 constitutive activation in TKI-resistant cancer cells have not yet been explored. In this study, we recapitulated this finding by taking advantage of a gefitinib-resistant patient-derived xenograft (PDX) model established through a number of passages in mice treated with increasing doses of gefitinib. The dissociated primary cells from the resistant PDX tumors (PDX-R) displayed higher levels of phosphor-S6K1 expression and were resistant to gefitinib compared to cells from passage-matched parental PDX tumors (PDX-P). Both genetic and pharmacological inhibition of S6K1 increased sensitivity to gefitinib in PDX-R cells. In addition, both total and phosphorylated mechanistic target of rapamycin kinase (MTOR) levels were upregulated in PDX-R and gefitinib-resistant PC9G cells. Knockdown of MTOR by siRNA decreased the expression levels of total and phosphor-S6K1 and increased sensitivity to gefitinib in PDX-R and PC9G cells. Moreover, a transcription factor ELK1, which has multiple predicted binding sites on the MTOR promoter, was also upregulated in PDX-R and PC9G cells, while the knockdown of ELK1 led to decreased expression of MTOR and S6K1. The chromatin immunoprecipitation (ChIP)-PCR assay showed the direct binding between ELK1 and the MTOR promoter, and the luciferase reporter assay further indicated that ELK1 could upregulate MTOR expression through tuning up its transcription. Silencing ELK1 via siRNA transfection improved the efficacy of gefitinib in PDX-R and PC9G cells. These results support the notion that activation of ELK1/MTOR/S6K1 signaling contributes to acquired resistance to gefitinib in NSCLC. The findings in this study shed new light on the mechanism for acquired EGFR-TKI resistance and provide potential novel strategies by targeting the ELK1/MTOR/S6K1 pathway.

Molecular Engineering of Electrosprayed Hydrogel Microspheres to Achieve Synergistic Anti-Tumor Chemo-Immunotherapy with ACEA Cargo.

Molecular engineering of drug delivering platforms to provide collaborative biological effects with loaded drugs is of great medical significance. Herein, cannabinoid receptor 1 (CB1)- and reactive oxygen species (ROS)-targeting electrosprayed microspheres (MSs) are fabricated by loading with the CB1 agonist arachidonoyl 2'-chloroethylamide (ACEA) and producing ROS in a photoresponsive manner. The synergistic anti-tumor effects of ACEA and ROS released from the MSs are assessed. ACEA inhibits epidermal growth factor receptor signaling and altered tumor microenvironment (TME) by activating CB1 to induce tumor cell death. The MSs are composed of glycidyl methacrylate-conjugated xanthan gum (XGMA) and Fe3+, which form dual molecular networks based on a Fe3+-(COO-)3 network and a C═C addition reaction network. Interestingly, the Fe3+-(COO-)3 network can be disassembled instantly under the conditions of lactate sodium and ultraviolet exposure, and the disassembly is accompanied by massive ROS production, which directly injures tumor cells. Meanwhile, the transition of dual networks to a single network boosts the ACEA release. Together, the activities of the ACEA and MSs promote immunogenic tumor cell death and create a tumor-suppressive TME by increasing M1-like tumor-associated macrophages and CD8+ T cells. In summation, this study demonstrates strong prospects of improving anti-tumor effects of drug delivering platforms through molecular design.

TMED2 promotes glioma tumorigenesis by being involved in EGFR recycling transport

Aberrant epidermal growth factor receptor (EGFR) signaling is the core signaling commonly activated in glioma. The transmembrane emp24 protein transport domain protein 2 (TMED2) interacts with cargo proteins involved in protein sorting and transport between endoplasmic reticulum (ER) and Golgi apparatus. In this study, we found the correlation between TMED2 with glioma progression and EGFR signaling through database analysis. Moreover, we demonstrated that TMED2 is essential for glioma cell proliferation, migration, and invasion at the cellular levels, as well as tumor formation in mouse models, underscoring its significance in the pathobiology of gliomas. Mechanistically, TMED2 was found to enhance EGFR-AKT signaling by facilitating EGFR recycling, thereby providing the initial evidence of TMED2's involvement in the membrane protein recycling process. In summary, our findings shed light on the roles and underlying mechanisms of TMED2 in the regulation of glioma tumorigenesis and EGFR signaling, suggesting that targeting TMED2 could emerge as a promising therapeutic strategy for gliomas and other tumors associated with aberrant EGFR signaling.

Development of tight junction-strengthening compounds using a high-throughput screening system to evaluate cell surface-localized claudin-1 in keratinocytes

Tight junctions (TJs) are important factors constituting the physical barriers of the skin, and their suppression has been described in various conditions, such as aged skin and atopic dermatitis lesions. However, the methods for improving skin TJ function remain insufficient. Therefore, to obtain compounds that can improve TJ function, we developed a novel high-throughput screening system termed live-cell immunostaining to evaluate cell surface-localized claudin-1 (CLDN1) with high selectivity using normal human epidermal keratinocytes (NHEKs). Heparinoid and phospho-pyridoxal (p-Pyr), a metabolite of pyridoxine, were identified as hit compounds. In addition, heparinoid was strongly suggested to increase CLDN1 expression by inhibiting epidermal growth factor receptor signaling. By contrast, p-Pyr did not enhance CLDN1 expression, but it accelerated the translocation of CLDN1 to the cell surface. Finally, we confirmed that heparinoid and p-Pyr improved barrier function in NHEKs in a transepithelial electrical resistance assay. In conclusion, heparinoid and p-Pyr could potentially ameliorate skin conditions by improving TJ function.

The efficacy and safety of tinengotinib in patients with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC).

133 Background: Tinengotinib is a spectrum-selective multi-kinase inhibitor that targets cell proliferation, angiogenesis, and immune-oncology pathways by inhibiting Aurora kinases A/B, Janus kinases (JAK), and receptor tyrosine kinases (FGFRs, VEGFRs). It has been reported that the activation of JAK/STAT and fibroblast growth factor receptor (FGFR) signaling drives prostate tumor plasticity. Here we present the preliminary safety and efficacy data of tinengotinib in patients with mCRPC from three early phase clinical trials conducted in the US and China. Methods: Eligible mCRPC patients who have no available standard therapeutic treatment options were enrolled to the three studies. Tinengotinib was given as monotherapy at 8 mg QD, 10 mg QD and 12 mg QD. Efficacy tumor assessments were based on RECIST v1.1 for measurable disease and Prostate Cancer Working Group 3 criteria for non-measurable (bone) disease. PSA50 response was also evaluated. CTCAE v5.0 was used for safety assessments. Results: As of 28AUG2023, 30 patients with mCRPC were treated at dose levels of 8 mg QD (n=1), 10 mg QD (n=19) and 12 mg QD (n=10). Median age was 67 years (range 52-82) with ECOG performance status of 1 in 93% of patients. All patients had at least 2 prior therapies including 77% prior docetaxel, 87% prior abiraterone, and 30% prior enzalutamide. The median follow-up time is 5.4 months. Twenty-two (22) patients were efficacy evaluable, of which 13 were evaluable per RECIST v1.1. Fourteen (14) patients were PSA evaluable. The median radiographic progression-free survival (rPFS) was 5.6 months (95% CI, 3.3-7.3). Overall response rate (ORR) was 46% (6/13) and the disease control rate (DCR) was 85% (11/13). Median duration of response (DoR) was 3.0 months. The PSA50 response rate was 50% (7/14). Treatment-related adverse events (TRAEs) occurred in 28 patients (93%). The most common TRAEs (≥20%) included blood thyroid stimulating hormone increase (43%), anemia (37%), hypertension (27%), aspartate aminotransferase increase (23%), electrocardiogram QT prolongation (20%) and white blood cell count decrease (20%). Conclusions: Tinengotinib safety profile was tolerable and manageable. The preliminary efficacy data showed promising clinical benefit of tinengotinib monotherapy in patients with heavily pretreated mCRPC. Further study of tinengotinib in this disease is warranted. Clinical trial information: NCT03654547 , NCT04742959 , NCT05253053 .

Abstract B066: PDGFR upregulation functions as a bypass mechanism contributing to FGFR inhibitor resistance in metastatic breast cancer

Abstract Breast cancer (BC) is the most diagnosed cancer in females in the United States and the second leading cause of cancer related deaths among women. The fibroblast growth factor receptor (FGFR) signaling pathway is frequently activated in BC, making it an attractive therapeutic target, especially in metastatic disease. However, clinical trials using FGFR inhibitors in BC have been disappointing in comparison to other cancer types treated with these therapies. As a result, BC patients with activated FGFR do not have a targeted therapeutic option. Failure of FGFR inhibitors is indicative of intrinsic or acquired resistance mechanisms in metastatic BC. Herein we demonstrate significant efficacy of the FGFR inhibitor, pemigatinib, in the 4T07 murine model of BC utilizing a tail vein model to induce pulmonary tumors. Despite this initial response, pemigatinib fails to eliminate minimal residual disease (MRD) and allows for accelerated tumor return after pemigatinib cessation. Characterizing the MRD by IHC following pemigatinib treatment shows that expression of platelet-derived growth factor receptor (PDGFR) is significantly increased on tumor cells. This rise in PDGFR expression following pemigatinib treatment increases the responsiveness of 4T07 cells to platelet-derived growth factor ligand indicating PDGFR may act as an alternate signaling pathway bypassing FGFR signaling. Mechanistically, previous studies indicate that PDGFR protein expression is transcriptionally repressed by restriction of enhancer positioning by the CTCF insulator. DNA methylation surrounding CTCF causes its dissociation enhancing protein expression of PDGFR. Along these lines cotreatment with a DNA methyl transferase inhibitor prevents the increase of PDGFR protein expression induced by pemigatinib. Overall, our study determined that a highly potent FGFR inhibitor can inhibit tumor growth in a metastatic site, but it fails to eliminate MRD giving rise to tumor recurrence. Upregulation of PDGFR may act as a bypass mechanism of resistance allowing for tumor cell survival during pemigatinib treatment. Finally, our findings suggest that dual inhibition of DNA methylation and FGFR could improve patient response in metastatic BC. Citation Format: Mitchell Ayers, Michael Wendt. PDGFR upregulation functions as a bypass mechanism contributing to FGFR inhibitor resistance in metastatic breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B066.

Amphiregulin from regulatory T cells promotes liver fibrosis and insulin resistance in non-alcoholic steatohepatitis

Production of amphiregulin (Areg) by regulatory T (Treg) cells promotes repair after acute tissue injury. Here, we examined the function of Treg cells in non-alcoholic steatohepatitis (NASH), a setting of chronic liver injury. Areg-producing Treg cells were enriched in the livers of mice and humans with NASH. Deletion of Areg in Treg cells, but not in myeloid cells, reduced NASH-induced liver fibrosis. Chronic liver damage induced transcriptional changes associated with Treg cell activation. Mechanistically, Treg cell-derived Areg activated pro-fibrotic transcriptional programs in hepatic stellate cells via epidermal growth factor receptor (EGFR) signaling. Deletion of Areg in Treg cells protected mice from NASH-dependent glucose intolerance, which also was dependent on EGFR signaling on hepatic stellate cells. Areg from Treg cells promoted hepatocyte gluconeogenesis through hepatocyte detection of hepatic stellate cell-derived interleukin-6. Our findings reveal a maladaptive role for Treg cell-mediated tissue repair functions in chronic liver disease and link liver damage to NASH-dependent glucose intolerance.

The Efficient Activity of Glabridin and its Derivatives Against EGFRmediated Inhibition of Breast Cancer.

Breast cancer (BC) is one of the most typical causes of cancer death in women worldwide. Activated epidermal growth factor receptor (EGFR) signaling has been increasingly associated with BC development and resistance to cytotoxic drugs. Due to its significant association with tumour metastasis and poor prognosis, EGFR-mediated signaling has emerged as an attractive therapeutic target in BC. Mainly in all BC cases, mutant cells over-expresses EGFR. Certain synthetic drugs are already used to inhibit the EGFR-mediated pathway to cease metastasis, with several phytocompounds also revealing great chemopreventive activities. This study used chemo-informatics to predict an effective drug from some selected phytocompounds. The synthetic drugs and the organic compounds were individually screened for their binding affinities, with EGFR being the target protein using molecular docking techniques. The binding energies were compared to those of synthetic drugs. Among phytocompounds, Glabridin (phytocompound of Glycyrrhiza glabra</i>) manifested the best dock value of -7.63 Kcal/mol, comparable to that of the highly effective anti-cancer drug Afatinib. The glabridin derivatives also exhibited comparable dock values. The AMES properties deciphered the non-toxic features of the predicted compound. Pharmacophore modeling and in silico</i> cytotoxicity predictions also exhibited a superior result assuring their drug likeliness. Therefore, Glabridin can be conceived as a promising therapeutic method to inhibit EGFR-mediated BC.

Identification of Piperazinyl-Difluoro-indene Derivatives Containing Pyridyl Groups as Potent FGFR Inhibitors against FGFR Mutant Tumor: Design, Synthesis, and Biological Evaluation.

The fibroblast growth factor receptor (FGFR) signaling pathway plays important roles in cellular processes such as proliferation, differentiation, and migration. In this study, we highlighted the potential of FGFR inhibitors bearing the (S)-3,3-difluoro-1-(4-methylpiperazin-1-yl)-2,3-dihydro-1H-indene scaffold containing a crucial 3-pyridyl group for the treatment of FGFR mutant cancers. The representative compound (S)-23, which was identified through comprehensive evaluation, exhibited potent antiproliferative activity with GI50 in the range of 6.4-10.4 nM against FGFR1 fusion protein-carrying, FGFR2-amplified, and FGFR2 mutant cancer cell lines and good antiproliferative activity against FGFR3 translocation and mutant FGFR4 cancer cell lines, as well as potency assessment against FGFR1-4 kinases. Moreover, compound (S)-23 exhibited favorable pharmacokinetic properties, low potential for drug-drug interactions, and very potent antitumor activity in MFE-296 xenograft mouse models with a TGI of 99.1% at the dose of 10 mg/kg. These findings demonstrate that compound (S)-23 is a potential therapeutic agent for FGFR mutant tumors.

Proteomic insights into mental health status: plasma markers in young adults

Global emphasis on enhancing prevention and treatment strategies necessitates an increased understanding of the biological mechanisms of psychopathology. Plasma proteomics is a powerful tool that has been applied in the context of specific mental disorders for biomarker identification. The p-factor, also known as the “general psychopathology factor”, is a concept in psychopathology suggesting that there is a common underlying factor that contributes to the development of various forms of mental disorders. It has been proposed that the p-factor can be used to understand the overall mental health status of an individual. Here, we aimed to discover plasma proteins associated with the p-factor in 775 young adults in the FinnTwin12 cohort. Using liquid chromatography–tandem mass spectrometry, 13 proteins with a significant connection with the p-factor were identified, 8 of which were linked to epidermal growth factor receptor (EGFR) signaling. This exploratory study provides new insight into biological alterations associated with mental health status in young adults.

P167 Remodelling of the colonic molecular landscape in patients failing anti-TNF therapy highlights dysregulation of the extracellular matrix in ulcerative colitis

Abstract Background In patients with ulcerative colitis (UC) who previously failed anti-TNF therapy, subsequent treatment with other advanced therapies is generally less effective than they are in anti-TNF naïve patients. Since anti-TNF drugs are frequently used first-line in UC, drug sequencing depreciation poses a major clinical challenge. To understand potential underlying mechanisms, we compared the clinical and molecular phenotype of UC patients who failed anti-TNF therapy with those who were anti-TNF naïve. Methods Clinical information and mucosal gene expression profiles were collected from 262 anti-TNF naïve and 275 anti-TNF exposed individuals with moderate to severe UC enrolled in the UNIFI clinical trial programme. We assessed differences between the groups in terms of clinical parameters, gene expression levels, pathway and transcription factor activity, as well as cellular composition. Results Anti-TNF exposed patients had significantly increased disease duration (p=0. 000009), CRP (p=0.03), and histological severity[PN1] (p=0.002). After adjusting for these factors, we identified 1,592 genes differentially expressed (FDR &amp;lt; 0.05), although the expression changes were quite modest. Pathway analysis linked previous anti-TNF exposure to significant downregulation of TNF and NFkB signalling and up-regulation of extracellular matrix components, stroma-related signatures, and growth factor receptor (EGFR, MAPK, PI3K) and TGFb signalling. These data were in line with results from cellular deconvolution methods, which showed an increase in stromal cell abundance and T cell depletion following anti-TNF failure. Gene regulatory network inference suggested that the observed gene expression differences were driven by increased activity of many transcriptional regulators, including those downstream of RUNX1 and RUNX3. Conclusion In patients with active UC, prior anti-TNF failure is associated with molecular remodelling of the colon characterised by dysregulated ECM organisation and shifts in stromal compartments. These data provide new insights into potential mechanisms of drug sequencing depreciation and could inform novel strategies to overcome this challenging clinical phenomenon.

SOS2 modulates the threshold of EGFR signaling to regulate osimertinib efficacy and resistance in lung adenocarcinoma.

Son of sevenless 1 and 2 (SOS1 and SOS2) are RAS guanine nucleotide exchange factors (RasGEFs) that mediate physiologic and pathologic receptor tyrosine kinase (RTK)-dependent RAS activation. Here, we show that SOS2 modulates the threshold of epidermal growth factor receptor (EGFR) signaling to regulate the efficacy of and resistance to the EGFR tyrosine kinase inhibitor (EGFR-TKI) osimertinib in lung adenocarcinoma (LUAD). SOS2 deletion (SOS2KO ) sensitized EGFR-mutated cells to perturbations in EGFR signaling caused by reduced serum and/or osimertinib treatment to inhibit phosphatidylinositol 3-kinase (PI3K)/AKT pathway activation, oncogenic transformation, and survival. Bypassing RTK reactivation of PI3K/AKT signaling represents a common resistance mechanism to EGFR-TKIs; SOS2KO reduced PI3K/AKT reactivation to limit osimertinib resistance. In a forced HGF/MET-driven bypass model, SOS2KO inhibited hepatocyte growth factor (HGF)-stimulated PI3K signaling to block HGF-driven osimertinib resistance. Using a long-term in situ resistance assay, most osimertinib-resistant cultures exhibited a hybrid epithelial/mesenchymal phenotype associated with reactivated RTK/AKT signaling. In contrast, RTK/AKT-dependent osimertinib resistance was markedly reduced by SOS2 deletion; the few SOS2KO cultures that became osimertinib resistant primarily underwent non-RTK-dependent epithelial-mesenchymal transition (EMT). Since bypassing RTK reactivation and/or tertiary EGFR mutations represent most osimertinib-resistant cancers, these data suggest that targeting proximal RTK signaling, here exemplified by SOS2 deletion, has the potential to delay the development osimertinib resistance and enhance overall clinical responses for patients with EGFR-mutated LUAD.

Gefitinib enhances healing of long bone fractures in rats via inhibition of the epidermal growth factor receptor signal pathway

Purpose: To investigate the influence of gefitinib on healing of long bone fractures in rats, and the involvement of epidermal growth factor receptor (EGFR) signal route in the process.&#x0D; Methods: A model of long bone fracture was established in 30 Sprague-Dawley (SD) rats which were allocated to control and study groups (n = 15/group). Rats in study group received gefitinib (100 mg/kg per day) via gavage, while control rats were given 0.55 % methylcellulose daily for 7 - 42 days. Fracture healing, maximum callus diameter, serum levels of bone markers and mRNA levels of bone turnover indices in the callus, were determined.&#x0D; Results: Following 1 week of therapy, fracture lines were clear in both groups, and callus was produced. On days 7, 14, 21, and 28, maximum callus diameter of study group was significantly higher than that of control group (p &lt; 0.05). However, there was no significant difference in the maximum callus diameter between the two groups after 42 days (p &gt; 0.05). On days 7, 14 and 21, there were significantly higher BALP and PINP levels, and TRACP-5b and CTX values in study group than in control (p &lt; 0.05). On days 7 and 14, study group COLa1 mRNA and osteocalcin (OC) mRNA was significantly raised, relative to control values. On days 7, 14 and 21, COL10 mRNA expression was significantly up-regulated in study group relative to controls (p &lt; 0.05). However, mRNA expression levels of COLa1, OC, COL10, and COL2A1 were similar in both groups at other time points.&#x0D; Conclusion: Gefitinib enhances the healing of long bone fractures and callus formation in rats, probably through inhibition of EGFR signaling pathway. Therefore, gefitinib is beneficial in bone formation in rats.

Anticancer effect of zoledronic acid in endocrine-resistant breast cancer cells via HER-2 signaling

HER-2 overexpression is a major mechanism involved in endocrine-resistant breast cancer, which has very limited treatment options. Zoledronic acid (ZA) is a drug in the bisphosphonate group used to treat osteoporosis. ZA was reported to exhibit activity in various cancers, with higher efficacy associated with estrogen-deprivation states. ZA inhibits cell proliferation in lung cancer through the epidermal growth factor receptor signaling pathway. Because endocrine-resistant breast cancer cells overexpress HER-2 and grow independently without estrogen, ZA may exert anticancer effects in these cell types. The inhibitory effects and mechanisms of ZA in endocrine-resistant cells through HER-2 signaling were investigated. The efficacy of ZA was higher in the endocrine-resistant breast cancer cells when compared with the wild-type cells. ZA also exhibited a synergistic effect with fulvestrant and may circumvent fulvestrant resistance. ZA decreased phosphorylated ERK (pERK) levels in resistant cell lines and attenuated HER-2 signaling in tamoxifen- and fulvestrant-resistant cells. ZA significantly decreased HER-2 levels and its downstream signaling molecules, including pAKT and pNF-κB in fulvestrant-resistant breast cancer cells. This inhibitory effect may explain the lower IC50 values of ZA in fulvestrant-resistant cells compared with tamoxifen-resistant cells. Moreover, ZA inhibited the migration and invasion in the resistant cell lines, suggesting an ability to inhibit tumor metastasis. The results indicate that ZA has potential for repurposing as an adjuvant treatment for patients with endocrine-resistant breast cancer.