Activation Of Growth Factor Receptor Research Articles

A selective Fibroblast Growth Factor Receptor 1/2 PROTAC degrader with antitumor activity.

The aberrant activation of fibroblast growth factor receptor (FGFR) acts as a potent driver of multiple types of human cancers. Despite the development of several conventional small-molecular FGFR inhibitors, their clinical efficacy is largely compromised due to low selectivity and side effects. Here, we report the selective FGFR1/2-targeting proteolysis targeting chimeric (PROTAC), BR-cpd7 that displays significant isoform specificity to FGFR1/2 with DC50 values around 10 nM, while sparing FGFR3. The following mechanistic investigation reveals the reduced FGFR signaling, through which BR-cpd7 induces cell cycle arrest and consequently blocks the proliferation of multiple FGFR1/2-dependent tumor cells. Importantly, BR-cpd7 has almost no anti-proliferative activity against cancer cells without FGFR aberrations, furtherly supporting its selectivity. In vivo, BR-cpd7 exhibits robust antitumor effects in FGFR1-dependent lung cancer at well-tolerated dose schedules, accompanied by complete FGFR1 depletion. Overall, we identify BR-cpd7 as a promising candidate for developing a selective FGFR1/2-targeted agent, thereby offering a new therapeutic strategy for human cancers in which FGFR1/2 plays a critical role.

Synergistic Effects of Neratinib in Combination With Palbociclib or Miransertib in Brain Cancer Cells.

Aberrant expression and activation of epidermal growth factor receptor (EGFR) resulted in approval of several forms of EGFR inhibitors in the treatment of patients with a wide range of epithelial cancers. However, no EGFR inhibitor has yet been approved for the treatment of patients with brain cancer, indicating that targeting EGFR alone may not be sufficient in some patients. In this study, we investigated the role of all members of the EGFR family, other growth factor receptors, cell-cycle proteins, and downstream cell signaling pathways (e.g., mitogen-activated protein kinase (MAPK), serine/threonine protein kinase (AKT), signal transducer and activator of transcription (STAT3), Src, Abelson murine leukemia viral oncogene homolog (Abl)) on the growth of a panel of human brain cancer cell lines (HBCCLs). We examined the growth response of HBCCLs to treatment with 17 targeted agents compared to two cytotoxic drugs. Of the targeted agents, the irreversible pan-human epidermal growth factor receptor (HER) inhibitors neratinib and afatinib were more effective than erlotinib and lapatinib at inhibiting the growth of all HBCCLs, and the cyclin-dependent kinase (CDK)1/2/5/9 inhibitor dinaciclib was the most potent targeted agent. We found that treatment with Src/Abl/c-kit inhibitor dasatinib, signal transducer and activator of transcription (STAT3) inhibitor stattic, Abl/platelet-derived growth factor receptor (PDGFR)α/vascular endothelial growth factor (VEGFR)2/fibroblast growth factor receptor (FGFR)1 inhibitor ponatinib, and the tropomyosin receptor kinase (TRK)/ROS proto-oncogene 1 receptor tyrosine kinase (ROS)/anaplastic lymphoma kinase (ALK) inhibitor entrectinib, also inhibited the growth of all HBCCLs. Interestingly, these agents were more effective in inhibiting growth of HBCCLs when proliferating at a slower rate. In addition to inhibiting the proliferation of HBCCLs, treatment with neratinib, dinaciclib, dasatinib, stattic and trametinib inhibited the migration of brain tumor cell line A172. Notably, we found that treatment with neratinib in combination with palbociclib (CDK4/6 inhibitor), or miransertib (AKT1/2/3 inhibitor) resulted in synergistic growth inhibition of all HBCCLs. Our results support that repurposing drugs like neratinib in combination with the palbociclib or miransertib may be of therapeutic potential in brain cancer and warrants further investigations.

Futibatinib: A Review in Locally Advanced and Metastatic Cholangiocarcinoma.

Futibatinib (LYTGOBI®) is an oral small molecule compound that selectively, irreversibly and potently inhibits the tyrosine kinase activity of fibroblast growth factor receptor (FGFR)1-4. It is approved in the EU, Japan and the USA for the treatment of adults with locally advanced or metastatic cholangiocarcinoma (CCA) harbouring an FGFR2 fusion or rearrangement who have progressed following systemic therapy. In the phase II part (FOENIX-CCA2) of a multinational phase I/II study in this patient population, monotherapy with futibatinib 20mg once daily was associated with clinically meaningful and durable responses, sustained health-related quality of life (HR-QOL), and a manageable safety profile with supportive care and as-needed dose modifications. Indeed, hyperphosphataemia (the most common all grade and grade 3 treatment-related adverse event) was manageable with phosphate-lowering therapy and dose reductions or interruptions. Although further efficacy and tolerability data are expected, current evidence indicates that futibatinib is a valuable targeted therapy option for adults with locally advanced or metastatic CCA harbouring an FGFR2 fusion or rearrangement who have progressed following systemic therapy, a patient population with limited treatment options and poor life expectancy.

Seralutinib in adults with pulmonary arterial hypertension (TORREY): a randomised, double-blind, placebo-controlled phase 2 trial

Morbidity and mortality in pulmonary arterial hypertension (PAH) remain high. Activation of platelet-derived growth factor receptor, colony stimulating factor 1 receptor, and mast or stem cell growth factor receptor kinases stimulates inflammatory, proliferative, and fibrotic pathways driving pulmonary vascular remodelling in PAH. Seralutinib, an inhaled kinase inhibitor, targets these pathways. We aimed to evaluate the efficacy and safety of seralutinib in patients with PAH receiving standard background therapy. The TORREY trial was a phase 2, randomised, multicentre, multinational, double-blind, placebo-controlled study. Patients with PAH from 40 hospital and community sites were randomly assigned 1:1 via interactive response technologies to receive seralutinib (60 mg twice daily for 2 weeks, then increased to 90 mg twice daily as tolerated) or placebo by dry powder inhaler twice daily for 24 weeks. Randomisation was stratified by baseline pulmonary vascular resistance (PVR; <800 dyne·s/cm5 and ≥800 dyne·s/cm5). Patients were eligible if classified as WHO Group 1 PH (PAH), WHO Functional Class II or III, with a PVR of 400 dyne·s/cm5 or more, and a 6 min walk distance of between 150 m and 550 m. The primary endpoint was change in PVR from baseline to 24 weeks. Analyses for efficacy endpoints were conducted in randomly assigned patients (intention-to-treat population). Safety analyses included all patients who received the study drug. TORREY was registered with ClinicalTrials.gov (NCT04456998) and EudraCT (2019-002669-37) and is completed. From Nov 12, 2020, to April 20, 2022, 151 patients were screened for eligibility, and following exclusions, 86 adults receiving PAH background therapy were randomly assigned to seralutinib (n=44; four male, 40 female) or placebo (n=42; four male, 38 female), and comprised the intention-to-treat population. At baseline, treatment groups were balanced except for a higher representation of WHO Functional Class II patients in the seralutinib group. The least squares mean change from baseline to week 24 in PVR was 21·2 dyne·s/cm5 (95% CI -37·4 to 79·8) for the placebo group and -74·9 dyne·s/cm5 (-139·7 to -10·2) for the seralutinib group. The least squares mean difference between the seralutinib and placebo groups for change in PVR was -96·1 dyne·s/cm5 (95% CI -183·5 to -8·8; p=0·03). The most common treatment-emergent adverse event in both treatment groups was cough: 16 (38%) of 42 patients in the placebo group; 19 (43%) of 44 patients in the seralutinib group. Treatment with inhaled seralutinib significantly decreased PVR, meeting the primary endpoint of the study among patients receiving background therapy for PAH. Gossamer Bio.

Deletion of Mitogen-inducible gene-6 (Mig6) in the Liver Alters Glucose Homeostasis and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) Progression

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a spectrum of chronic liver disease that can progress from benign steatosis to metabolic dysfunction-associated steatohepatitis (MASH) - both of which, if left untreated, can progress to cirrhosis and hepatocellular carcinoma. The strongest risk factor for progression of MASLD to MASH is insulin resistance. Previous work in our lab identified that the adaptor protein mitogen-inducible gene-6 (Mig6) is increased in obese mice and that deletion of Mig6 in the liver (LKO) improves glucose tolerance and insulin action during hyperinsulinemic-euglycemic clamps in diet-induced obese mice. Mig6 is an endogenous feedback inhibitor of epidermal growth factor receptor activation (EGFR) and regulates cellular repair and survival. Thus, we sought to elucidate the extent to which loss of Mig6 modulates the progression of MASLD to MASH. We hypothesized that liver-specific loss of Mig6 during early MASLD improves whole-body glucose homeostasis and protects against MASLD-mediated liver damage. LKO mice and matched, control littermates (CON) were fed a MASH diet (40% fat, 40% carbohydrate, 2% cholesterol; CON n=13-19, LKO n=16-22) or a low-fat-matched diet (LFD; 10% fat, 70% carbohydrate; CON n=8-16, LKO n=16-21) for up to 40 weeks. Body weights were recorded weekly, and body composition assessment, glucose and insulin tolerance tests, and hepatic histological analysis were performed after 20-, 30- and 40-weeks on each diet. Compared to the MASH-fed CON mice, MASH-fed LKO mice had lower body weights starting at 10-weeks and persisting throughout the study. Body composition analysis established these differences in body weight were due to decreases in fat, but not lean, mass. Interestingly, whereas intraperitoneal glucose tolerance tests did not identify significant differences in glucose handling between the LFD and MASH fed mice, oral glucose tolerance was significantly improved in 10- and 20-week MASH-fed LKO mice, suggesting alterations in the incretin response in this MASH model. Lastly, histological analysis revealed MASH-fed LKO mice had a preservation of hepatic lipid zonation and blunted levels of circulating alanine aminotransferase (ALT) compared to MASH-fed CON, indicating less hepatic damage in LKO mice. These results suggest that liver-specific loss of Mig6 improves whole-body glucose handling, which in turn ameliorates hepatic damage during MASLD progression. In conclusion, Mig6 prevents, or at least delays, the progression of MASLD, which may reveal a new therapeutic area for the prevention and treatment of MASH. MS was supported by a National Cancer Institute Cancer Metabolism Training Program Postdoctoral Fellowship (T32CA221709). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Hepatocellular RECK as a Critical Regulator of Metabolic Dysfunction-Associated Steatohepatitis Development

REversion inducing Cysteine rich protein with Kazal motifs (RECK) is an extracellular matrix regulator with anti-fibrotic effects. However, its expression and role in metabolic dysfunction-associated steatohepatitis (MASH) and hepatic fibrosis are poorly understood. We generated a novel transgenic mouse model with RECK overexpression specifically in hepatocytes to investigate its role in Western diet (WD)-induced liver disease. Proteomic analysis and in vitro studies were performed to mechanistically link RECK to hepatic inflammation and fibrosis. Our results show that RECK expression is significantly decreased in liver biopsies from human patients diagnosed with MASH and correlated negatively with severity of metabolic dysfunction-associated steatotic liver disease (MASLD) and fibrosis. Similarly, RECK expression is downregulated in WD-induced MASH in wild type mice. Hepatocyte-RECK overexpression significantly reduced hepatic pathology in WD-induced liver injury. Proteomic analysis highlighted changes in extracellular matrix and cell-signaling proteins. In vitro mechanistic studies linked RECK induction to reduced ADAM10 (A Disintegrin And Metalloproteinase domain-containing protein 10) and ADAM17 activity, amphiregulin release, epidermal growth factor receptor activation, and stellate cell activation. Our in vivo and mechanistic in vitro studies reveal that RECK is a novel upstream regulator of inflammation and fibrosis in the diseased liver, its induction is hepatoprotective, and thus highlight its potential as a novel therapeutic in MASH.

Loss of tumor suppressor TMEM127 drives RET-mediated transformation through disrupted membrane dynamics

Internalization from the cell membrane and endosomal trafficking of receptor tyrosine kinases (RTKs) are important regulators of signaling in normal cells that can frequently be disrupted in cancer. The adrenal tumor pheochromocytoma (PCC) can be caused by activating mutations of the rearranged during transfection (RET) receptor tyrosine kinase, or inactivation of TMEM127, a transmembrane tumor suppressor implicated in trafficking of endosomal cargos. However, the role of aberrant receptor trafficking in PCC is not well understood. Here, we show that loss of TMEM127 causes wildtype RET protein accumulation on the cell surface, where increased receptor density facilitates constitutive ligand-independent activity and downstream signaling, driving cell proliferation. Loss of TMEM127 altered normal cell membrane organization and recruitment and stabilization of membrane protein complexes, impaired assembly, and maturation of clathrin-coated pits, and reduced internalization and degradation of cell surface RET. In addition to RTKs, TMEM127 depletion also promoted surface accumulation of several other transmembrane proteins, suggesting it may cause global defects in surface protein activity and function. Together, our data identify TMEM127 as an important determinant of membrane organization including membrane protein diffusability and protein complex assembly and provide a novel paradigm for oncogenesis in PCC where altered membrane dynamics promotes cell surface accumulation and constitutive activity of growth factor receptors to drive aberrant signaling and promote transformation.

Loss of tumor suppressor TMEM127 drives RET-mediated transformation through disrupted membrane dynamics.

Internalization from the cell membrane and endosomal trafficking of receptor tyrosine kinases (RTKs) are important regulators of signaling in normal cells that can frequently be disrupted in cancer. The adrenal tumor pheochromocytoma (PCC) can be caused by activating mutations of the rearranged during transfection (RET) receptor tyrosine kinase, or inactivation of TMEM127, a transmembrane tumor suppressor implicated in trafficking of endosomal cargos. However, the role of aberrant receptor trafficking in PCC is not well understood. Here, we show that loss of TMEM127 causes wildtype RET protein accumulation on the cell surface, where increased receptor density facilitates constitutive ligand-independent activity and downstream signaling, driving cell proliferation. Loss of TMEM127 altered normal cell membrane organization and recruitment and stabilization of membrane protein complexes, impaired assembly, and maturation of clathrin-coated pits, and reduced internalization and degradation of cell surface RET. In addition to RTKs, TMEM127 depletion also promoted surface accumulation of several other transmembrane proteins, suggesting it may cause global defects in surface protein activity and function. Together, our data identify TMEM127 as an important determinant of membrane organization including membrane protein diffusability and protein complex assembly and provide a novel paradigm for oncogenesis in PCC where altered membrane dynamics promotes cell surface accumulation and constitutive activity of growth factor receptors to drive aberrant signaling and promote transformation.

Computational Analysis of Activation of Dimerized Epidermal Growth Factor Receptor Kinase Using the String Method and Markov State Model.

Epidermal growth factor receptor (EGFR) activation is accompanied by dimerization. During the activation of the intracellular kinase domain, two EGFR kinases form an asymmetric dimer, and one side of the dimer (receiver) is activated. Using the string method and Markov state model (MSM), we performed a computational analysis of the structural changes in the activation of the EGFR dimer in this study. The string method reveals the minimum free-energy pathway (MFEP) from the inactive to active structure. The MSM was constructed from numerous trajectories of molecular dynamics simulations around the MFEP, which revealed the free-energy map of structural changes. In the activation of the receiver kinase, the unfolding of the activation loop (A-loop) is followed by the rearrangement of the C-helix, as observed in other kinases. However, unlike other kinases, the free-energy map of EGFR at the asymmetric dimer showed that the active state yielded the highest stability and revealed how interactions at the dimer interface induced receiver activation. As the H-helix of the activator approaches the C-helix of the receiver during activation, the A-loop unfolds. Subsequently, L782 of the receiver enters the pocket between the G- and H-helices of the activator, leading to a rearrangement of the hydrophobic residues around L782 of the receiver, which constitutes a structural rearrangement of the C-helix of the receiver from an outward to an inner position. The MSM analysis revealed long-time scale trajectories via kinetic Monte Carlo.

Abstract CT152: FURTHER: A global study to evaluate furmonertinib in patients with EGFR mutant NSCLC including uncommon EGFR mutations

Abstract Background: Furmonertinib (AST2818) is an oral, highly brain-penetrant, and broadly active mutation-selective epidermal growth factor receptor (EGFR) inhibitor engineered for broad activity and selectivity across EGFR mutations (mts) (Musib et al., NACLC 2022). Furmonertinib is approved in China for first-line advanced NSCLC with EGFR Ex19del or L858R mts based on the positive Phase 3 study (FURLONG) versus gefitinib. Furmonertinib has also demonstrated promising interim efficacy and safety in patients (pts) with NSCLC with EGFR exon 20 insertion (ex20ins) mts with a confirmed overall response rate (ORR) of 78.6% (n=28) by blinded independent central review (BICR) with a preliminary median duration of response (DoR) of 15.2 months in the front-line setting (FAVOUR study; see Han et al., WCLC 2023). Furmonertinib recently obtained FDA Breakthrough Therapy Designation for the treatment of pts with advanced NSCLC with EGFR ex20ins mts. P-loop and αC-helix Compressing (PACC) mts represent another subset of uncommon EGFR mts (Robichaux et al., 2021) that are similar to ex20ins mts in narrowing the drug-binding pocket; including G719X, S768I, E709X, L747X, V774M. Preclinical data indicating that furmonertinib is potent in models harboring EGFR PACC mts will be presented at this meeting (Nilsson et al., Abstract #4174). Developing efficacious, well-tolerated, and CNS-penetrant medicines for NSCLC pts with EGFR ex20ins mts and PACC mts remains an unmet need. Methods: FURTHER (FURMO-002) is the first global trial evaluating furmonertinib in NSCLC pts with EGFR and HER2 mts in North America, Europe, and the Asia-Pacific. FURTHER is a phase 1b, open-label, multicenter study in which pts will be treated orally with furmonertinib daily. For Stage 1 dose-escalation, the primary endpoint is incidence and severity of adverse events, including dose limiting toxicities and has been completed. For Stage 2 dose expansion, approximately 120 pts will be enrolled across 4 expansion cohorts. Stage 2 Cohorts 1-3 dose expansion cohorts will enroll pts with previously treated, locally advanced or metastatic NSCLC pts with either EGFR ex20ins mts, HER2 ex20ins mts, or EGFR activating mts, respectively. Cohorts 1-3 allow enrollment of pts with prior EGFR or HER2-directed therapy. Stage 2 Cohort 4 will enroll EGFR TKI-naïve NSCLC pts with EGFR PACC mts. Key inclusion criteria include documented EGFR or HER2 mts by local testing and measurable disease per RECIST v1.1. Stage 2 primary endpoint is ORR using RECIST v1.1. Key secondary endpoints include progression-free survival and overall survival. Stage 2 enrollment is ongoing. Clinical trial information: NCT05364073. Citation Format: Xiuning Le, Alexander Spira, Shirish Gadgeel, Yan Yu, Yanqiu Zhao, Ying Cheng, Jonathan Riess, Oscar Juan-Vidal, Bo Gao, Kiyotaka Yoh, Martin Forster, Satoru Kitazono, Hidetoshi Hayashi, David Planchard, Yong Jiang, Jack Huang, Nichole Baio, Marcin Kowanetz, Shirley Wang, William Leung, Jerry Y. Hsu, Jie Wang. FURTHER: A global study to evaluate furmonertinib in patients with EGFR mutant NSCLC including uncommon EGFR mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT152.

Mechanism of pruritus ani lotion combined with Huajiao-Gancao-Bingpian oil for pruritus ani treatment based on network pharmacology and molecular dynamics.

Pruritus ani lotion combined with a Chinese medicine formula named Huajiao (Pericarpium Zanthoxyli Bungeani)-Gancao (Radix Glycyrrhizae)-Bingpian (Borneol) is effective in treating pruritus ani. To investigate the mechanism of traditional Chinese medicine (TCM) in pruritus ani via network pharmacology and molecular dynamics (MD). The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) was utilised to screen active ingredients and their corresponding targets. Genes associated with pruritus ani were collected through GeneCards. Protein-protein interaction (PPI) network between target genes of the active ingredients of this formula and genes associated with pruritus ani was established through the STRING database. A drug-active ingredient-gene interaction network was constructed using Cytoscape with the top 50 genes in affinity coefficients. Molecular docking and MD simulation analysis were performed. Epidermal growth factor receptor (EGFR) and Signal Transducer and Activator of Transcription 3 (STAT3) were core genes. Direct targeting of EGFR by the active ingredients (quercetin and luteolin) and direct targeting of STAT3 by the active ingredient (licochalcone A) may be key molecular mechanisms for the treatment of pruritus ani. Simulated trajectories of structural nuclear motion by MD also revealed that the binding of two pairs of molecules was relatively stable. This study unravels potential targets, active ingredients, and mechanisms of pruritus ani lotion combined with Huajiao-Gancao-Bingpian oil in the treatment of pruritus ani, providing a reference for future treatment.

Paradoxical cancer cell proliferation after FGFR inhibition through decreased p21 signaling in FGFR1-amplified breast cancer cells

Fibroblast growth factors (FGFs) control various cellular functions through fibroblast growth factor receptor (FGFR) activation, including proliferation, differentiation, migration, and survival. FGFR amplification in ER + breast cancer patients correlate with poor prognosis, and FGFR inhibitors are currently being tested in clinical trials. By comparing three-dimensional spheroid growth of ER + breast cancer cells with and without FGFR1 amplification, our research discovered that FGF2 treatment can paradoxically decrease proliferation in cells with FGFR1 amplification or overexpression. In contrast, FGF2 treatment in cells without FGFR1 amplification promotes classical FGFR proliferative signaling through the MAPK cascade. The growth inhibitory effect of FGF2 in FGFR1 amplified cells aligned with an increase in p21, a cell cycle inhibitor that hinders the G1 to S phase transition in the cell cycle. Additionally, FGF2 addition in FGFR1 amplified cells activated JAK-STAT signaling and promoted a stem cell-like state. FGF2-induced paradoxical effects were reversed by inhibiting p21 or the JAK-STAT pathway and with pan-FGFR inhibitors. Analysis of patient ER + breast tumor transcriptomes from the TCGA and METABRIC datasets demonstrated a strong positive association between expression of FGF2 and stemness signatures, which was further enhanced in tumors with high FGFR1 expression. Overall, our findings reveal a divergence in FGFR signaling, transitioning from a proliferative to stemness state driven by activation of JAK-STAT signaling and modulation of p21 levels. Activation of these divergent signaling pathways in FGFR amplified cancer cells and paradoxical growth effects highlight a challenge in the use of FGFR inhibitors in cancer treatment.

Abstract 1930: Combination of KRASG12C and FGFR1 inhibitors as a resistance-overcoming therapeutic strategy for maximizing therapeutic impact of KRASG12C inhibitors

Abstract INTRODUCTION: Lung cancer is the leading cause of cancer-related deaths worldwide. KRAS is the most frequent mutated driver gen in lung adenocarcinoma (LUAD). KRASG12C inhibitors (G12Ci) have revealed promising results in the clinic, having being approved two G12Ci for the treatment of LUAD patients, which marks the first approved targeted therapy for KRAS-mutant tumors. Nevertheless, these therapies face the same limitation as other targeted therapies, the therapeutic potential of these inhibitors can be impaired by resistance mechanisms. Deciphering resistance mechanisms to G12Ci is of prime relevance to predict which patients may benefit from these therapies and to propose resistance-overcoming therapeutic strategies for maximizing therapeutic impact of these inhibitors. MATERIAL AND METHODS: We generated 10 acquired resistant LUAD cell lines to G12Ci (Sotorasib and Adagrasib), exposing sensitive cells to increasing concentrations of drugs. All the acquired resistant models were characterized at the proteomic (phospho-Array and Western Blot) and transcriptomic (WTS) levels to find signatures that define the resistance.The efficacy of G12Ci was tested in vitro in a panel of 8 cell lines and 7 PDX-derived organoids (PDXDO) models and in vivo in 7 patient-derived xenografts (PDX) models to classify them as resistant, sensitive or partially sensitive. The efficacy of the combination of FGFR1 and G12Ci was tested in vitro in the panel of 10 acquired resistant cell lines but also in the parental cell lines and PDXDOs (sensitive and intrinsic resistant) and in vivo in the intrinsic resistant PDXs. RESULTS AND DISCUSSION: The characterization of 10 acquired resistant cell lines at the proteomic and transcriptomic levels showed differences in the expression and/or activation of Fibroblast Growth Factor Receptors (FGFRs) in more than 50% of them. The combination of KRASG12C and FGFR1 inhibitors in all acquired resistant cell lines showed efficacy, regardless of whether acquired resistance was mediated or not by FGFR1 overexpression/overactivation.In addition, the combination of KRASG12C and FGFR1 inhibitors showed more efficacy than the monotherapies in most intrinsically resistant cell lines, PDXDOs and PDXs models. Finally, we tested the combination with FGFR1i in sensitive or partially responsive models, observing an improvement in efficacy compared to monotherapy with G12Ci. CONCLUSIONS: The activation or overexpression of FGFR1 acts as a mechanism of acquired resistance to KRASG12C inhibitors.-The combination of FGFR and KRASG12C inhibitors is effective as an acquired/intrinsic resistance-overcoming therapeutic strategy in cell lines, PDXDOs and PDXs models.-The combination of FGFR and KRASG12C inhibitors is also synergistic for sensitive models, which could maximize therapeutic impact of KRASG12C inhibitors. Citation Format: Alba Santos, Patricia Plaza, Marta Jimenez, David Gómez-Sánchez, Luis Paz-Ares, Irene Ferrer. Combination of KRASG12C and FGFR1 inhibitors as a resistance-overcoming therapeutic strategy for maximizing therapeutic impact of KRASG12C inhibitors [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 1930.

Abstract 4736: Evaluate the potential sensitization effect and underlying mechanism of lenvatinib on cisplatin resistance oral squamous cell carcinoma

Abstract Oral squamous cell carcinoma (OSCC) is a prevalent form of cancer that develops in the oral cavity, globally recognized as the eighth most commonly diagnosed cancer. Despite the application of standard surgical techniques or concurrent chemoradiotherapy, the prognosis for OSCC patients remains unsatisfactory. Initially, cisplatin, the primary and most frequently used chemotherapy agent for treating OSCC, demonstrates effectiveness in therapy. Nonetheless, chemoresistance frequently arises, leading to treatment failure, and this is intricately associated with the activation of hypoxia-inducible factor 1α (HIF-1α) signaling. Recent research has brought to light heightened levels of HIF-1α-mediated vascular endothelial growth factor (VEGF) and BCL-2 in OSCC tumor sites, which play crucial roles in regulating angiogenesis and anti-apoptotic processes within cancer cells. Additionally, interventions aimed at targeting anti-apoptotic molecules or augmenting the expression of pro-apoptotic molecules may represent promising strategies to overcome chemoresistance in OSCC. Therefore, HIF-1α/VEGF/BCL-2 axis could be considered a potential target for the development of chemopreventive and chemotherapeutic strategies for OSCC. Lenvatinib is a targeted multi-kinase inhibitor that can inhibit tumor growth and angiogenesis by blocking the activation of vascular endothelial growth factor receptor (VEGFR) 1-3, fibroblast growth factor receptor (FGFR) 1-4, platelet-derived growth factor receptor (PDGFR) α, as well as the proto-oncogenes RET and KIT. However, whether lenvatinib may sensitizes OSCC to cisplatin remains unclear. In our study, we used the MTT assay to prove the cytotoxicity of OSCC cells (SAS and MOC1 cells) was induced by cisplatin and lenvatinib. We employed flow cytometry to verify that the combination of lenvatinib and cisplatin can indeed trigger both extrinsic and intrinsic apoptotic pathways in OSCC cells. Furthermore, our demonstration revealed that the induction of apoptosis pathways by the combination of lenvatinib and cisplatin is associated with mitochondrial-dependent apoptosis and death receptor-dependent apoptosis. Then, transwell invasion and migration assay results proved the inhibition effect of lenvatinib combined with cisplatin in SAS and MOC1 cells. Furthermore, we indicated that the combination of lenvatinib and cisplatin can effectively inhibit angiogenesis and anti-apoptotic mechanisms mediated by the HIF-1α/VEGF/BCL-2 axis in OSCC cells. In summary, our results demonstrate that the combined treatment with lenvatinib and cisplatin enhances the response of OSCC cells under hypoxic conditions. Additionally, it aims to mitigate the negative impact of hypoxia on cisplatin's therapeutic effectiveness and increase the sensitivity of OSCC cells to cisplatin. Citation Format: Ying-Tzu Chen, Yan-Ting Tsai, Fei-Ting Hsu, Hsi-Feng Tu. Evaluate the potential sensitization effect and underlying mechanism of lenvatinib on cisplatin resistance oral squamous cell carcinoma [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 4736.

Abstract 5152: Co-expression and prognostic significance of HER family members and EGFRvIII in patients with hepatocellular carcinoma

Abstract Hepatocellular carcinoma is one of the most common type of liver cancer. Despite advances in its treatment including the approval of several targeted agents in the past few decades, many patients do not respond or have a response of short duration to such therapeutic interventions. As a result, liver cancer is the third leading cause of cancer-related deaths worldwide. Therefore, it is essential to identify additional therapeutic targets and to develop more effective therapeutic interventions. In the past few decades, increased expression, and activation of the human epidermal growth factor receptor (HER) family members have been detected in various cancer types and of these, EGFR and HER2 are important therapeutic targets for the treatment of patients with a wide range of cancers, but currently not in liver cancer. In some studies, cross-talk between different members of the HER family has been associated with tumor progression and resistance to therapy with EGFR inhibitors but there has been no comprehensive study of the expression of all members of the HER family in patients with hepatocellular carcinoma. In this study, we examined the relative expression of all members of the HER family, type-III deletion mutant of EGFR (i.e.EGFRvIII), which is a tumor specific antigen, and two putative liver cancer cell biomarkers (i.e. CD44, EpCAM) in 43 patients with hepatocellular carcinoma by immunohistochemistry. The prognostic significance of such antigens was also investigated. Of these, the expression of EGFR, HER2, HER3, HER4 and EGFRvIII was found in tumor specimens from 35%, 58%, 0%, 19%, and 26% of the cases, respectively. Interestingly, at a cut off value of &amp;gt;5% of tumor cells with staining, 23%, 14% and 9% of the patients had co-expression of EGFR with HER2, EGFRvIII, and HER2/EGFRvIII. In addition, 40% and 33% of the cases were CD44 and EpCAM positive. Of these, the expression of EGFRvIII positivity at &amp;gt;5% ( HR=3.35, p=0.002) and 20% (HR=7.22, p=0.003) of tumour cells and membranous CD44 ( HR=2.12, p=0.04) were associated with a poorer survival in patients with hepatocellular carcinoma. In contrast, the expression of cytoplasmic CD44 was associated with a better overall survival (HR=0.30, p=0.02). These were found to be independent prognostic markers in multivariate analysis. Interestingly, the co-expression of EGFR with EGFRvIII was associated with a poorer overall survival (59.5 vs 21.0 months, p=0.004). Taken together, our results suggest that the expression of EGFRvIII occurs in patients with hepatocellular carcinoma and highlight its importance as biomarker for tumor progression and as a potential target for therapeutic intervention with drugs targeting EGFRvIII and other members of HER family. Citation Format: Ozlem Sherif, Said Khelwatty, Izhar Bagwan, Alan Seddon, Angus Dalgleish, Satvinder Mudan, Helmout Modjtahedi. Co-expression and prognostic significance of HER family members and EGFRvIII in patients with hepatocellular carcinoma [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 5152.

Abstract 160: FGFR1+ cancer associated fibroblasts (CAFs) produce an extracellular matrix (ECM) that curbs infiltration of phagocytic tumor-associated macrophages (TAMs)

Abstract About 40% of diffuse large B-cell lymphoma (DLBCL) pts do not respond to immunochemotherapy. In human and murine models, we and others have shown that the lymphoma microenvironment (LME) changes with disease progression and treatment resistance. This lymphoma cell-LME co-evolutionary process results in expansion of treatment-resistant lymphoma cells as well as reduced infiltration of T cells and reprogramming of CAFs and TAMs into immune suppressive entities. Our analysis of relapse or refractory (RR)-DLBCLs showed not only an immune depleted LME but also an enrichment of CAFs harboring activation of fibroblast growth factor receptor (FGFR1+). Since FGFR1 inhibitors (FGFR1i) are clinically available, we sought to determine its anti-neoplastic effect on DLBCL. We first confirmed that lymphoma cells, including murine and human, and primary and RR-DLBCLs, did not express FGFR1. Accordingly, no anti-tumoral effect was detected when the selective FGFR1i SSR128129E was administered in vitro to a lymphoma cell panel. However, oral administration of FGFR1i to pre-clinical lymphoma models including two RR-DLBCL patient-derived xenografts (PDX) and four syngeneic murine models representing distinct DLBCL genetic subtypes produced a significant anti-lymphoma effect in all cases. In addition to decreased lymphoma cells, we observed increase in the ECM and TAM infiltration, even in the murine models, suggesting that FGFR1i reprogrammed the CAFs. We thus conducted matrisome analysis (i.e., ECM proteomics) in a murine model (p53 mutant) and found a significant up-regulation of proteoglycans and the immune active glycoproteins decorin, lumican and byglican (q-value &amp;lt;0.05 vs. vehicle). To determine whether these ECM changes affect lymphoma cells, we performed 3D co-cultures of lymphoma cells embedded into de-celularized ECM obtained from FGFR1i vs. vehicle mice. We found that FGFR1i-ECM (vs. vehicle-ECM) modifies the secretome of lymphoma cells by upregulating several cytokines including IL6, IL16 and TNF-alpha. To further characterize the functional state of CAFs and TAMs, we conducted single cell RNA-seq in the two RR-DLBCL PDXs treated as before. We found that FGFR1-CAFs in the LME of FGFR1i tumors (vs. vehicle) were reprogrammed into inflammatory-like CAFs characterized by the expression of several monocyte/macrophage chemotactic factors including CCL2, CCL7, CXCL3, and CXCL12. Consequent with these findings we not only observed an increase infiltration of TAMs in the LME of FGFR1i tumors but also that they were reprogrammed in phagocytic phenotypes. In sum, our results suggest that CAF-FGFR1+ produce an immune “silent” ECM that characterizes RR-DLBCL while FGFR1i reverses this ECM phenotype ultimately resulting in the infiltration of antitumoral TAMs, delineating a novel ECM-directed therapeutic approach for this disease. Citation Format: Nicolás Di Siervi, Maria Victoria Revuelta, Nahuel Zamponi, Giorgio Inghirami, Leandro Cerchietti. FGFR1+ cancer associated fibroblasts (CAFs) produce an extracellular matrix (ECM) that curbs infiltration of phagocytic tumor-associated macrophages (TAMs) [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 160.

Abstract 7217: Orthogonal targeting of NAD metabolism and ErbB2/ErbB3 signaling in pancreatic adenocarcinoma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is now the third leading cause for cancer related deaths in the US with a five-year survival of ~10% that has improved little over the past 20 years. Thus, there is a critical need to fully understand mechanisms of PDAC tumorigenesis in order to develop novel and effective therapies. Nicotinamide Adenine Dinucleotide (NAD), a critical co-factor and energy source required for cellular processes such as DNA repair and epigenetic regulation is frequently upregulated in PDAC. We recently reported a novel oncogenic axis connecting the NAD-dependent epigenetic regulator and oncogene C-terminal Binding Protein (CtBP) with the EGFR family growth factor receptors ErbB2/ErbB3 (ErbB2/3) in PDAC cells and tumors. Indeed, previous reports have shown ~30% of human PDAC tumors overexpress ErbB3, and our work has shown that PDAC tumor cell growth relies on maintenance of ErbB3 expression. Moreover, we show that the majority of PDAC cells with high levels of ErbB3 expression are uniquely sensitive to the ErbB2-targeted tyrosine kinase inhibitor lapatinib. In addition, we have recently shown that co-targeting NAD and CtBP with small molecule inhibitors is an effective and synergistic therapeutic strategy in PDAC model systems. Methods and Results: In the current study, we demonstrate NAD-dependent regulation of ErbB2/3 signaling in PDAC cells in vitro. Upon depletion of NAD using the NAD salvage pathway inhibitor GMX1778 in human PDAC cells, we observed a striking coordinate decrease in the levels of both ErbB2 and ErbB3. Furthermore, stable knockdown of the limiting enzyme of the complementing Preiss-Handler NAD synthetic pathway, Nicotinamide Adenine Phosphoribosyl Transferase, also resulted in robust downregulation of ErbB2/3 protein levels, suggesting a direct linkage in PDAC cells between the status of NAD metabolism and synthesis and activity of the key growth factor receptors ErbB2/3. Conclusions: Our findings highlight the novel connection between NAD and ErbB2/3 in PDAC. Furthermore, our data suggests combining chemical or biologic inhibitors of ErbB2/3 with an inhibitor of NAD synthesis may result in highly synergistic cytotoxic effects in PDAC cells and PDAC preclinical models. Such data could support the future development of a human PDAC clinical trial repurposing agents targeting NAD synthesis and ErbB2/3 that are already FDA-approved or currently in clinical testing. Citation Format: Kranthi Kumar Chougoni, Nari Kim, Martin M. Dcona, Diana T. Dcona, Gautam K. Malhotra, Steven R. Grossman. Orthogonal targeting of NAD metabolism and ErbB2/ErbB3 signaling in pancreatic adenocarcinoma [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 7217.

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 3287: Learning to target CDK4/6 inhibitor resistance via a breast cancer-specific atlas of cellular mechanisms

Abstract Development of resistance to targeted, chemotherapeutic, and immune-oncology treatments alike is a major barrier to long-term remission in advanced cancer patients. We developed an integrated computational-experimental platform to mitigate treatment resistance by identifying therapeutics that selectively target clinical resistance mechanisms. The key innovation is the computational framework that comprehensively maps tumor-specific mechanisms of response and resistance to a treatment based on clinicogenomic and/or preclinical pharmacogenomic data. It then screens for drugs or targets that are synthetically lethal with these resistance mechanisms. Here we present the identification of therapeutic options that mitigate resistance to CDK4/6 inhibitors as a case study. Leveraging a breast cancer-specific atlas of cellular architecture, our framework learned genetic mechanisms of CDK4/6 inhibitor resistance from a high-throughput phenotypic screen of ~700 cell lines treated with the clinical CDK4/6 inhibitor palbociclib. The learned mechanisms formed a parsimonious set of hierarchically linked protein complexes that coordinate G1-to-S transition (P=5.6 × 10−12). The mechanisms unified distinct resistant populations such as samples resistant due to CDK4/6-Rb checkpoint bypass and those resistant due to growth factor receptor activation. Applied to 70 ER+ metastatic breast cancer patients in a real-world dataset, the learned resistance mechanisms accurately predicted patient response to palbociclib (P=3 × 10−4, log-rank test). Computationally screening 20K clinical-grade small molecules and gene targets for therapeutic options synthetically lethal with the learned resistance mechanisms identified the known CDK4/6 resistance targets CDK2, CCNE1, and E2F. It also identified a target that, to our knowledge, has not previously been rigorously evaluated for its potential to mitigate CDK4/6 inhibitor resistance. In-vitro, monotherapy inhibition of the target by siRNA selectively decreased growth of breast cancer cell lines resistant to CDK4/6 inhibitors by 52% compared to CDK4/6i sensitive cell lines (P=0.023, Mann-Whitney U-test). As a combination therapy, inhibition of the target by siRNA selectively increased the sensitivity to palbociclib by nearly an order of magnitude in an otherwise resistant breast cancer cell line (expected vs observed IC50: 9.7 uM vs. 1.3 uM) while not having a substantial effect in a palbociclib-sensitive cell line (expected vs observed IC50: 0.57 uM vs. 0.56 uM). Finally, while monotherapy inhibition of the target and CDK4/6 induced cell cycle arrest, the combination strongly induced apoptosis in cell lines resistant to CDK4/6 inhibitors. These results highlight how computational deconvolution of tumor resistance mechanisms enable algorithmic identification of therapeutic options to target treatment-resistant cell populations. Citation Format: Adam Yaari, Eduardo Farias, Francisco Guedes, Oliver Priebe, Lee McDaniel, Tyler Earnest, Trey Ideker, Maxwell A. Sherman. Learning to target CDK4/6 inhibitor resistance via a breast cancer-specific atlas of cellular mechanisms [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 3287.

Abstract 6236: Systems biology modeling identifies SMARCD3 as a master regulator facilitating everolimus resistance in ER+ breast cancer

Abstract Breast cancer is the most common malignancy in women and estrogen receptor positive (ER+) breast cancers represent nearly 75% of all breast tumors. Everolimus, an mTORC1 inhibitor, in combination with exemestane has been approved for patients with metastatic ER+ breast cancer. However, many patients eventually develop resistance to everolimus and leads to poor survival outcomes. Characterizing everolimus-resistant cells can reveal targetable molecular phenotypes that can eventually lead to new therapeutic targets. In this study, we elucidate systems-level phenotypic distinctions between everolimus sensitive and refractory cells. We generated several isogenic ER+ breast cancer cell lines resistant or sensitive to everolimus. We then leveraged transcriptomic profiles from sensitive and resistant cells before or after everolimus treatment to decipher the underlying mechanisms essential to the resistant state. Using linear mixed effect models, we identified several meta-phenotypes that were distinct between sensitive and resistant cell states. These included growth-factor signaling, cell cycle, metabolism, stemness, and apoptosis meta-phenotypes. Our analyses also identified strong activation of growth-factor receptors including IGF1R/INSR and ESR1 in the resistant cells, which were maintained despite everolimus treatment. Next, we adopted a transcriptional regulatory network reconstruction framework to identify the master regulators responsible for the activation of resistance meta-phenotypes. We identified SMARCD3 as the key master regulator controlling expression of genes across diverse resistance meta-phenotypes, including growth-factor signaling. Further, using transcriptomic profiles from a neoadjuvant trial of 23 post-menopausal ER+ breast cancers treated with everolimus, we found that SMARCD3 expression was elevated in resistant tumors. To confirm the role of SMARCD3 in everolimus resistance, we repressed transcription of the SMARCD3 gene using CRISPR interference to re-sensitize resistant cells to everolimus treatment. In conclusion, we used context-specific cell transcriptomic profiles and integrative systems-biology approaches to elucidate mechanisms of resistance in response to everolimus treatment in ER+ breast cancer. Our findings suggest SMARCD3 upregulation promotes resistance to everolimus treatment and may serve as a novel therapeutic target in ER+ breast cancer. Citation Format: Eric F. Medina, Patrick A. Cosgrove, Eleni Farmaki, Vince K. Grolmusz, Feng Chi, Jason I. Griffiths, Andrea H. Bild, Aritro Nath. Systems biology modeling identifies SMARCD3 as a master regulator facilitating everolimus resistance in ER+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6236.