Receptor Tyrosine Kinase Family Research Articles

Enhanced EphB2-Specific Peptide Inhibitors through Stabilization of Polyproline II Helical Structure.

Ephrin (Eph) receptors are the largest family of receptor tyrosine kinases. Interactions between Eph receptors and their membrane-bound ephrin protein ligands are associated with many developmental processes as well as various cancers and neurodegenerative diseases. With significant crosstalk between different Eph receptors and ephrin ligands, there is an urgent need for high-affinity ligands that bind specifically to individual Eph receptors to interrogate and modulate their functions. Here, we describe the rational development of potent EphB2 receptor inhibitors derived from the EphB2 receptor-specific SNEW peptide. To improve inhibitory potency, we evaluated 20+ cross-linkers with the goal of spanning and stabilizing a single polyproline II helical turn observed when SNEW binds to the EphB2 receptor. Of the cross-linkers evaluated, an 11-atom cross-linker, composed of a rigid 2,7-dimethylnaphthyl moiety between two cysteine residues, was found to yield the most potent inhibitor. Analysis of the cyclized region of this peptide by NMR and molecular dynamics simulations suggests that cross-linking stabilizes the receptor-bound polyproline II helix structure observed in the receptor-peptide complex. Cross-linked SNEW variants retained binding specificity for EphB2 and showed cross-linker-dependent resistance to trypsin proteolysis. Beyond the discovery of more potent EphB2 receptor inhibitors, these studies illustrate a novel cyclization approach with potential to stabilize polyproline II helical structure in various peptides for specific targeting of the myriad protein-protein interactions (PPIs) mediated by polyproline II helices.

Gas6/AXL Alleviates Hepatic Ischemia/Reperfusion Injury by Inhibiting Ferroptosis via the PI3K/AKT Pathway.

Hepatic ischemia/reperfusion (I/R) injury is a major cause of complications in clinical liver surgery. AXL receptor tyrosine kinase (AXL) is a member of the TAM receptor tyrosine kinase family (TYRO3, AXL, and MERTK). Our previous study has shown that AXL expression was markedly upregulated in liver transplantation patients. However, the underlying mechanism of AXL in hepatic I/R injury remains unclear. A mouse liver warm I/R model and a primary hepatocyte hypoxia/reoxygenation model were established to investigate the role of AXL activation and ferroptosis in hepatic I/R injury by pretreating with recombinant mouse growth arrest-specific protein 6 (AXL activator) or R428 (AXL inhibitor). Moreover, we used LY294002 (phosphatidylinositol 3-kinase [PI3K] inhibitor) to evaluate the relationship between the PI3K/AKT (the Ser and Thr kinase AKT) pathway and ferroptosis in hepatic I/R injury. Hepatic I/R injury decreased phosphorylation AXL expression and enhanced ferroptosis in liver transplantation patients and hepatic I/R-subjected mice. AXL activation attenuated lipid peroxidation and ferroptosis in hepatic I/R injury in vivo and in vitro. Inhibition of AXL activation exacerbated liver pathological damage and liver dysfunction, as well as iron accumulation and lipid peroxidation in hepatic I/R injury. Mechanistically, activated growth arrest-specific protein 6/AXL and its downstream PI3K/AKT signaling pathway inhibited ferroptosis during hepatic I/R injury. AXL activation protects against hepatic I/R injury by preventing ferroptosis through the PI3K/AKT pathway. This study is the first investigation on the AXL receptor and ferroptosis, and activating AXL to mitigate ferroptosis may be an innovative therapeutic strategy to combat hepatic I/R injury.

GraphEGFR: Multi-task and transfer learning based on molecular graph attention mechanism and fingerprints improving inhibitor bioactivity prediction for EGFR family proteins on data scarcity.

The proteins within the human epidermal growth factor receptor (EGFR) family, members of the tyrosine kinase receptor family, play a pivotal role in the molecular mechanisms driving the development of various tumors. Tyrosine kinase inhibitors, key compounds in targeted therapy, encounter challenges in cancer treatment due to emerging drug resistance mutations. Consequently, machine learning has undergone significant evolution to address the challenges of cancer drug discovery related to EGFR family proteins. However, the application of deep learning in this area is hindered by inherent difficulties associated with small-scale data, particularly the risk of overfitting. Moreover, the design of a model architecture that facilitates learning through multi-task and transfer learning, coupled with appropriate molecular representation, poses substantial challenges. In this study, we introduce GraphEGFR, a deep learning regression model designed to enhance molecular representation and model architecture for predicting the bioactivity of inhibitors against both wild-type and mutant EGFR family proteins. GraphEGFR integrates a graph attention mechanism for molecular graphs with deep and convolutional neural networks for molecular fingerprints. We observed that GraphEGFR models employing multi-task and transfer learning strategies generally achieve predictive performance comparable to existing competitive methods. The integration of molecular graphs and fingerprints adeptly captures relationships between atoms and enables both global and local pattern recognition. We further validated potential multi-targeted inhibitors for wild-type and mutant HER1 kinases, exploring key amino acid residues through molecular dynamics simulations to understand molecular interactions. This predictive model offers a robust strategy that could significantly contribute to overcoming the challenges of developing deep learning models for drug discovery with limited data and exploring new frontiers in multi-targeted kinase drug discovery for EGFR family proteins.

Abstract PO1-04-03: Phase I/II Trial of Ibrutinib Plus Trastuzumab in HER2-Positive Metastatic Breast Cancer

Abstract Background: Ibrutinib is a first-in-class inhibitor of Bruton’s tyrosine kinase that has demonstrated potent inhibition of ErbB/HER family receptor tyrosine kinases in preclinical models. Ibrutinib also displays immunomodulatory effects, shifting the profile of the immune response from Th2-type to Th1-type cytokines (Dubovsky et al. 2013), resulting in enhanced antitumor immunity. As there is a need for novel HER2-targeted therapies following progression on established anti-HER2–directed therapies, and as combining multiple HER2-directed agents is more effective than single-agent therapy (Blackwell et al. 2012), this study explored the safety and efficacy of ibrutinib in combination with trastuzumab in patients (pts) with HER2-positive metastatic breast cancer (MBC) (NCT03379428). Trial design: Phase I was a dose-escalation study to define the recommended Phase II dose (RP2D) of ibrutinib plus trastuzumab. The primary objective of Phase II was to define the clinical benefit rate (CBR = complete response [CR] + partial response [PR] + stable disease [SD] ≥ 6 months) of ibrutinib plus trastuzumab; secondary objectives were to determine objective response rate (ORR = CR + PR), overall survival (OS), progression-free survival (PFS), and safety/tolerability. Pts had HER2-positive MBC with measurable disease per RECIST v1.1, disease progression on or within 6 months of completing ado-trastuzumab emtansine (T-DM1) therapy, and ≤4 (Phase I) or ≤5 (Phase II) prior chemotherapy regimens for MBC, with no limit on prior endocrine therapies. Results: 26 pts were treated in Phases I and II: median age, 65.1 y; 15.4% Asian, 15.4% Black, 46.2% Caucasian, 19.2% Hispanic, and 3.8% Other; 46.2% with ECOG performance status (PS) of 0, 42.3% with PS of 1, and 7.7% with PS of 2. Median prior lines of therapy for MBC was 2 (range: 0, 6); median prior lines of therapy in any setting was 4 (range: 1, 9). In any setting, 88.5% of pts had prior treatment (Tx) with trastuzumab, 80.8% had prior Tx with pertuzumab, and 100% had prior Tx with T-DM1. 0% of pts had brain, 38.5% had bone, 23.1% had liver, and 42.3% had lung metastases. All pts were HER2+ by local pathology, 61.5% positive by IHC and 42.3% by FISH; 12 pts had ER+ and/or PR+ and 14 pts had ER-/PR- cancers. The starting dose of ibrutinib for Phase I was 560 mg. Of the 3 pts enrolled at this dose level, all experienced grade 3 or higher adverse events (AEs), with 2 of the pts experiencing serious AEs (grade 4 alanine aminotransferase [ALT] increased and grade 5 respiratory failure). As such, 420 mg of ibrutinib was selected as the RP2D. At the time of data extraction, across Phase I/II, 16 pts (61.5%) experienced a Tx-related adverse event (TRAE). The most common (≥5%) TRAEs of any grade were bruising and rash (each 19.2%); fatigue and thrombocytopenia (each 15.4%); anemia, diarrhea, and edema (each 11.5%); and ALT increased, aspartate aminotransferase increased, blurred vision, ecchymoses, mucositis, nausea, pruritus, and vomiting (each 7.7%). A total of 5 pts (19.2%) experienced grade 3 or 4 TRAEs; no grade 5 TRAEs were reported. 26 pts were treated with ibrutinib and trastuzumab, and 26 pts were in the evaluable population. 1 pt had CR for an ORR of 3.8% (95% CIs: 0.1, 19.6); 9 pts had SD, and 4 pts had SD for ≥6 months for a CBR of 19.2% (95% CIs: 6.6, 39.4). Median OS was 27.1 months (range: 0.30, 27.1), and median PFS was 2.0 months (range: 0.03, 27.1). The PFS rate at 12 months was 34.6% (95% CIs: 15.6, 54.6). Conclusion: Ibrutinib plus trastuzumab had a manageable safety profile; however, the CBR did not reach the protocol-specified goal of 28%, and these results do not support further clinical investigation. An in-depth evaluation of the immune effects of ibrutinib in these pts is ongoing. Citation Format: Joyce O'Shaughnessy, Andrea Glidden, Tracy Locke, Amy Scales. Phase I/II Trial of Ibrutinib Plus Trastuzumab in HER2-Positive Metastatic Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-04-03.

Mer activation ameliorates nerve injury-induced neuropathic pain by regulating microglial polarization and neuroinflammation via SOCS3 in male rats.

Accumulating evidence has demonstrated that M1 microglial polarization and neuroinflammation worsen the development of neuropathic pain. However, the mechanisms underlying microglial activation during neuropathic pain remain incompletely understood. Myeloid-epithelial-reproductive tyrosine kinase (Mer), which is a member of the Tyro-Axl-Mer (TAM) family of receptor tyrosine kinases, plays a crucial role in the regulation of microglial polarization. However, the effect of Mer on microglial polarization during neuropathic pain has not been determined. In this study, western blotting, immunofluorescence analysis, quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay (ELISA) were used to examine the role of Mer in pain hypersensitivity and microglial polarization in rats with chronic constriction injury (CCI) of the sciatic nerve. The results indicated that Mer expression in microglia was prominently increased in the spinal cords of rats subjected to CCI. Furthermore, treatment with recombinant protein S (PS, an activator of Mer) alleviated mechanical allodynia and thermal hyperalgesia, promoted the switch in microglia from the M1 phenotype to the M2 phenotype, and ameliorated neuroinflammation in rats subjected to CCI. However, the use of suppressor of cytokine signalling 3 (SOCS3) siRNA abolished these changes. These results indicated that Mer regulated M1/M2 microglial polarization and neuroinflammation and may be a potential target for treating neuropathic pain.

Gender effect of glucose, insulin/glucagon ratio, lipids, and nitrogen-metabolites on serum HGF and EGF levels in patients with diabetes type 2.

Hepatocyte growth factor (HGF) exhibits potent growth-inducing properties across various tissues, while epidermal growth factor (EGF) acts as a molecular integration point for diverse stimuli. HGF plays a crucial role in hepatic metabolism, tissue repair, and offers protective effects on epithelial and non-epithelial organs, in addition to its involvement in reducing apoptosis and inflammation, underscoring its anti-inflammatory capabilities. The HGF-Met system is instrumental in hepatic metabolism and enhancing insulin sensitivity in animal diabetes models. Similarly, the EGF and its receptor tyrosine kinase family (EGFR) are critical in regulating cell growth, proliferation, migration, and differentiation in both healthy and diseased states, with EGF also contributing to insulin sensitivity. In this observational study, we aimed to identify correlations between serum levels of HGF and EGF, insulin, glucagon, glucose, and primary serum lipids in patients with type 2 diabetes mellitus (DM), taking into account the impact of gender. We noted differences in the management of glucose, insulin, and glucagon between healthy men and women, potentially due to the distinct influences of sexual hormones on the development of type 2 DM. Additionally, metabolites such as glucose, albumin, direct bilirubin, nitrites, and ammonia might influence serum levels of growth factors and hormones. In summary, our results highlight the regulatory role of insulin and glucagon in serum glucose and lipids, along with variations in HGF and EGF levels, which are affected by gender. This link is especially significant in DM, where impaired cell proliferation or repair mechanisms lead to metabolic changes. The gender-based differences in growth factors point to their involvement in the pathophysiology of the disease.

Abstract LB022: Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model

Abstract Adenoid cystic carcinoma (ACC) is a rare type of salivary gland cancer. Despite the many advances made in helping understand the disease behavior and characteristics, the prevailing challenge in managing patients with ACC is the lack of clinically approved systemic therapy drugs to successfully treat those with advanced recurrent or metastatic disease. There are multiple promising candidate agents being evaluated preclinically and in early phase clinical trials, yet an effective drug with consistent overall response remains to be identified. AXL is a member of the TAM family of tyrosine kinase receptors, and its overexpression and activation is generally associated with poor prognosis and chemoresistance in many cancer types. Previous reports show AXL is significantly upregulated in a subset of ACC tumors. Here, we evaluate the tumor growth inhibition effects of a newly developed antibody-drug-conjugate targeting AXL (ADCT-601) in a xenograft ACC cell line model. MDA-ACC-01 cells express high levels of cell surface AXL as confirmed by biochemical analysis. The tumor growth inhibition of MDA-ACC-01 cell xenograft was tested in a single-dose drug administration study. Immunodeficient mice bearing ACC tumors were either injected with vehicle (n=7) or with ADCT-601 at 0.5 (n=9) or 1.0 mg/kg (n=7). ADCT-601 treatment with either 0.5 mg/kg or 1.0 mg/kg resulted in complete response (CR) for all tumor implants. To reaffirm the drug’s efficacy, we challenged the vehicle-treated tumor, prior to exceeding the tumor volume endpoint, with a single-dose of ADCT-601 at 1.0 mg/kg. Strikingly, by day 6 post-treatment, tumor volume began to shrink and eventually resulted in CR except in all but one case. These results demonstrate ADCT-601 is an effective drug with significant anti-tumor activity in our preclinical models and is worthy of additional investigation to determine its translational potential. Citation Format: Joseph O. Humtsoe, Anita Pothukuchi, Hyunseok Kang, Patrick Ha. Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model [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 LB022.

Isthmin-1 promotes growth and progression of colorectal cancer through the interaction with EGFR and YBX-1

While previous studies have indicated the involvement of Isthmin 1 (ISM1), a secreted protein, in cancer development, the precise mechanisms have remained elusive. In this study, we unveiled that ISM1 is significantly overexpressed in both the blood and tissue samples of colorectal cancer (CRC) patients, correlating with their poor prognosis. Functional experiments demonstrated that enforced ISM1 expression significantly enhances CRC proliferation, migration, invasion and tumor growth. Notably, our investigation reveals an interaction of ISM1 with epidermal growth factor receptor (EGFR), a member of the receptor tyrosine kinase (RTK) family of CRC cells. The binding of ISM1 triggered EGFR activation and initiate downstream signaling pathways. Meanwhile, intracellular ISM1 interacted with Y-box binding protein 1 (YBX1), enhancing its transcriptional regulation on EGFR. Furthermore, our research uncovered the regulation of ISM1 expression by the hypoxia-inducible transcription factor HIF-1α in CRC cells. Mechanistically, we identified HIF-1α as a direct regulator of ISM1, binding to a hypoxia response element on its promoter. This novel mechanism illuminated potential therapeutic targets, offering insights into restraining HIF-1α/ISM1/EGFR-driven CRC progression and metastasis.

The Clinical Relevance of the EPH/Ephrin Signaling Pathway in Pediatric Solid and Hematologic Malignancies.

Pediatric neoplasms represent a complex group of malignancies that pose unique challenges in terms of diagnosis, treatment, and understanding of the underlying molecular pathogenetic mechanisms. Erythropoietin-producing hepatocellular receptors (EPHs), the largest family of receptor tyrosine kinases and their membrane-tethered ligands, ephrins, orchestrate short-distance cell-cell signaling and are intricately involved in cell-pattern morphogenesis and various developmental processes. Unraveling the role of the EPH/ephrin signaling pathway in the pathophysiology of pediatric neoplasms and its clinical implications can contribute to deciphering the intricate landscape of these malignancies. The bidirectional nature of the EPH/ephrin axis is underscored by emerging evidence revealing its capacity to drive tumorigenesis, fostering cell-cell communication within the tumor microenvironment. In the context of carcinogenesis, the EPH/ephrin signaling pathway prompts a reevaluation of treatment strategies, particularly in pediatric oncology, where the modest progress in survival rates and enduring treatment toxicity necessitate novel approaches. Molecularly targeted agents have emerged as promising alternatives, prompting a shift in focus. Through a nuanced understanding of the pathway's intricacies, we aim to lay the groundwork for personalized diagnostic and therapeutic strategies, ultimately contributing to improved outcomes for young patients grappling with neoplastic challenges.

Abstract 1970: Discovery and characterization of potent and selective HER2 exon20 insertion mutant inhibitors

Abstract Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for over 85% of all cases. Among NSCLC, approximately 2-4% of patients have mutations in the HER2, a member of the ErbB family of receptor tyrosine kinases and key proliferation driver, with exon 20 insertions making up about 90% of these mutations. HER2 exon mutations can have various alterations, and among them, the most common HER2 mutation is in-frame insertions in exon 20, especially the A775_G776insYVMA insertion/duplication. These mutations can affect the structure and function of the HER2 protein and may contribute to tumor development and growth. HER2 mutations have often shown resistance to EGFR tyrosine kinase inhibitors (TKIs), further highlighting the need for HER2-specific treatments. Also, inhibitors targeting HER2 mutations are selective, meaning they specifically target HER2 alterations without causing toxicities or affecting EGFRWT. Therefore, there is a need for the development of selective HER2 exon20 insertion mutant inhibitors. Herein, Hanmi has identified selective HER2 exon20 insertion mutant small molecule inhibitors, designed based on affinity and binding mode starting from a known crystal structure using GLIDE (Schrödinger), and the screening for the viability of cell lines including HER2A775_G776insYVMA, HER2G776delinsVC , HER2WT and EGFRWT was investigated. Hanmi's HER2 exon20 insertion mutant inhibitors selectively target mutant HER2 receptor tyrosine domains through shared binding, sparing EGFRWT and minimizing EGFR-related toxicities. With highly selectivity against EGFRWT and desirable pharmacokinetic properties, the Hanmi compounds inhibit HER2 mutant cells and HER2 mutant enzymes. Additionally, the compounds have an oral administration-compatible DMPK profile and demonstrated anti-tumor activity in HER2 mutant and HER2WT tumor xenograft mice. In conclusion, based on our study, Hanmi compounds, a novel HER2 exon20 insertion mutant inhibitors could be suggested as an appropriate therapeutic agent for inhibitory activity against HER2 exon20 insertion mutant NSCLC. Citation Format: Ho Yeon Nam, Sun Young Jang, Jiyoung Jeon, HyungSeok Yoo, Jooyun Byun, Gunwoo Lee, Youngjoo Lee, Yu-Yon Kim, Soye Jeon, Young Gil Ahn. Discovery and characterization of potent and selective HER2 exon20 insertion mutant 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 1970.

Abstract 2618: BCG017, a bispecific ADC targeting PTK7 and EGFR exhibits anti-tumor efficacy in PDX models

Abstract EGFR is a favored target in various cancer therapies. However, EGFR-based treatments have been challenged by drug resistance and cytotoxicity. Targeting EGFR with an antibody-drug conjugate (ADC) is a promising new therapeutic strategy to address the drug resistance, due to the potent killing effects of the payload. Furthermore, we hypothesized that development of a bispecific ADC (bsADC) targeting EGFR and another tumor-associated antigen (TAA) might improve the tumor selectivity, thereby limiting the on-target off-tumor toxicity. One such TAA candidate is PTK7, which belongs to the same receptor tyrosine kinase family as EGFR, and is co-expressed with EGFR in multiple types of solid tumors, including lung, esophageal, head and neck, and colon cancers. Herein, we developed a fully human anti-human PTK7 EGFR bsAb using our proprietary common light chain RenLite® mouse platform and knobs-into-holes technology. The anti-PTK7 EGFR bsAb demonstrates good purity by SEC-HPLC, and can cross-react with human and cynomolgus monkey antigens with favorable affinity. The PTK7 x EGFR bsAb demonstrated higher binding to various types of cancer cell lines, as well as enhanced internalization in vitro compared with PTK7 parental antibody. Next, the bsAb was conjugated with monomethyl auristatin E (MMAE) to generate an anti-PTK7 x EGFR bsADC, BCG017, with a drug-to-antibody ratio of approximately 4. BCG017 demonstrated superior anti-tumor activity compared to benchmarks and its PTK7 parental ADC in cell-derived non-small-cell lung cancer (NSCLC) xenografts, and showed enhanced anti-tumoractivity when compared to benchmark ADCs and parental ADCs in patient-derived breast and pancreatic ductal adenocarcinoma xenograft models. These results suggest that BCG017 have the potential to be a novel therapeutic alternative for PTK7 and EGFR co-expressing tumors. Citation Format: Sufei Yao, Chengzhang Shang, Zhuolin Li, Gao An, Chaoshe Guo, W. Frank An, Yi Yang. BCG017, a bispecific ADC targeting PTK7 and EGFR exhibits anti-tumor efficacy in PDX models [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 2618.

Multiple receptor tyrosine kinases regulate dengue infection of hepatocytes.

Dengue is an arboviral disease causing severe illness in over 500,000 people each year. Currently, there is no way to constrain dengue in the clinic. Host kinase regulators of dengue virus (DENV) infection have the potential to be disrupted by existing therapeutics to prevent infection and/or disease progression. To evaluate kinase regulation of DENV infection, we performed kinase regression (KiR), a machine learning approach that predicts kinase regulators of infection using existing drug-target information and a small drug screen. We infected hepatocytes with DENV in vitro in the presence of a panel of 38 kinase inhibitors then quantified the effect of each inhibitor on infection rate. We employed elastic net regularization on these data to obtain predictions of which of 291 kinases are regulating DENV infection. Thirty-six kinases were predicted to have a functional role. Intriguingly, seven of the predicted kinases - EPH receptor A4 (EPHA4), EPH receptor B3 (EPHB3), EPH receptor B4 (EPHB4), erb-b2 receptor tyrosine kinase 2 (ERBB2), fibroblast growth factor receptor 2 (FGFR2), Insulin like growth factor 1 receptor (IGF1R), and ret proto-oncogene (RET) - belong to the receptor tyrosine kinase (RTK) family, which are already therapeutic targets in the clinic. We demonstrate that predicted RTKs are expressed at higher levels in DENV infected cells. Knockdown of EPHB4, ERBB2, FGFR2, or IGF1R reduces DENV infection in hepatocytes. Finally, we observe differential temporal induction of ERBB2 and IGF1R following DENV infection, highlighting their unique roles in regulating DENV. Collectively, our findings underscore the significance of multiple RTKs in DENV infection and advocate further exploration of RTK-oriented interventions against dengue.

Abstract 3755: Impact of antigen retrieval and other parameters on detection of FGFR2b in various solid tumors on a BenchMark ULTRA automated staining platform: Development of a new IHC assay for FGFR2b

Abstract Background: Fibroblast growth factor receptor 2b (FGFR2b) is part of the FGFR transmembrane tyrosine kinase receptor family. This protein has gained more attention in recent years as a tumor progression biomarker in numerous solid tumors. The detection of FGFR2b by immunohistochemistry (IHC) has been used recently in immunotherapy clinical trials with multiple tumor types. During IHC assay development on formalin-fixed paraffin embedded tissue, a thorough study of antigen retrieval through cell conditioning or enzyme incubation, primary antibody incubation, and detection parameters is critical to evaluate staining performance. Design: A study of an investigational anti-FGFR2b (FPR2-D) assay developed on a BenchMark ULTRA automated staining platform explored the effect of antigen retrieval and detection parameters on staining performance. VENTANA System Software was used to modify steps in the IHC staining protocol resulting in 42 permutations. Ten different solid tumors were stained with these modifications to the assay and subsequently evaluated for FGFR2b expression. Result:s The results demonstrate that the staining clarity, intensity, and dynamic range within tissue cases of FGFR2b staining can vary widely between different solid tumor types. While most permutations of the initial assay parameters had minimal impact on the staining performance and readability by a pathologist, the order of the enzyme treatment and the cell conditioning steps (in addition to increased incubation time of primary antibody) had a significant impact when comparing across different solid tumors. Detection of FGFR2b seemed to have a greater susceptibility by tumor type to the antigen retrieval process than has traditionally been observed in other biomarkers. Conclusion: The overall results of this investigation show the importance of an extensive parameter screening approach when evaluating new antibody targets and indication combinations in IHC to ensure optimal staining performance. This is critical to downstream testing and the potential use of new assays in the context of in vitro diagnostics. Citation Format: Autumn Sky Watson, Catherine Le, Anne M. Wertheimer, Spencer Escobedo, Lisa So, Bhavani Bagevalu Siddegowda, John D. Palting, Susan Marion, Steven P. Stratton, Birte Aggeler. Impact of antigen retrieval and other parameters on detection of FGFR2b in various solid tumors on a BenchMark ULTRA automated staining platform: Development of a new IHC assay for FGFR2b [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 3755.

Abstract 2904: Small molecule inhibitor targeting DDR represents a novel therapeutic strategy for the treatment of pancreatic ductal adenocarcinoma (PDAC)

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is ranked as the second leading cause of cancer-related mortality with a 5-year survival rate of merely 12%. The complexity of PDAC lies in its intrinsic resistance to treatment, attributable to the desmoplastic tumor microenvironment, characterized by an abundance of tumor-promoting extracellular matrix (ECM) and stromal cells. We hypothesize that Discoidin Domain Receptors (DDR), members of the receptor tyrosine kinase family known for their affinity to fibrillar collagens within the ECM, play an important role in promoting PDAC growth and progression. While several drugs targeting DDR proteins have been developed, no inhibitors to DDR proteins are specific or approved for PDAC treatment, thus necessitating the development of novel therapeutic interventions. Methods. A comprehensive high-throughput screening approach employing small molecule inhibitors was executed to identify authentic inhibitors targeting DDR. Subsequently, a rigorous evaluation of specificity of these small molecules was conducted through structural activity relationship (SAR) analyses and reference-based assessments. The efficacy of candidate inhibitors was assessed through functional assays, while mechanistic insights were gleaned using a multifaceted approach, including RNA-seq, real-time PCR, western blot analysis, in vivo experimentation, and Phospho-Receptor Tyrosine Kinase (RTK) profiling to discern any unintended off-target effects. Results: Using an unbiased screening approach, we identified 13 inhibitors that specifically target DDR. SAR studies and cellular thermal shift assay validated CIDD-0108633 (8633) as a bona fide DDR2 inhibitor. Functional assays and RNA-seq analyses demonstrated 8633's capacity to inhibit PDAC growth, metastatic potential, and expression of DNA replication, cell-cycle, and DNA damage repair genes. Combination therapy of 8633 with gemcitabine synergistically reduced PDAC cell viability and metastatic potential. Mechanistic studies revealed the role of ABC transporters in mediating gemcitabine resistance. RTK profiling shows moderate kinase selectivity. In vivo studies affirmed its antitumor effects. Conclusions: The results indicate that the selective inhibition of DDR with small molecule inhibitors suppresses PDAC cell growth and progression, implying that DDR inhibitors have the potential to be developed as safe and efficacious therapeutics for the treatment of pancreatic cancers. Citation Format: Trong Phat Do, Jack Prochnau, Prabhakar Pitta Venkata, Sajid Khan, Santosh Timilsina, Deepika Singh, Daisy Medina, Radhika Amaradhi, Daohong Zhou, Matthew Hart, Stanton McHardy, Manjeet Rao. Small molecule inhibitor targeting DDR represents a novel therapeutic strategy for the treatment of pancreatic ductal adenocarcinoma (PDAC) [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 2904.

Insight into systematic development of ALK (anaplastic lymphoma kinase) inhibitors towards NSCLC treatment

Among cancer-related disorders, lung carcinoma is one of the leading causes of mortality. Anaplastic lymphoma kinase (ALK) belongs to tyrosine kinase receptor family and exhibits similar characteristics to insulin type receptors. The treatment of advanced non-small cell lung cancer (NSCLC) associates with ALK gene rearrangement has significantly improved since the approval of Crizotinib in 2011 as the first generation ALK inhibitor. In continuation, the second-generation drugs like ceritinib, alectinib, and brigatinib were developed to address and counteract resistance that was associated with the first-generation agents. However, resistance can develop over time, necessitating ongoing research to enhance their effectiveness. Therefore, the third-generation drug lorlatinib, which has demonstrated broad-spectrum potency against the majority of known resistance mutations and better lipophilicity, has been developed. According to current reports, the USFDA has approved five ALK-TKIs crizotinib, ceritinib, alectinib, brigatinib, and lorlatinib for ALK-associated lung cancer. Currently, several clinical trials are underway in search of better ALK inhibitors. Trials such as TPX-0131 and NVL-655 are considered fourth-generation ALK inhibitors for the treatment of patients with advanced ALK-positive or metastatic NSCLC. This review aims to provide specifics information on research works involving various ALK tyrosine kinase inhibitors, clinical studies, and the development of ALK TKIs. Additionally, we suggest potential future strategies involving sequential therapy and combination techniques for managing non-small cell carcinoma.

Targeting EphA2: a promising strategy to overcome chemoresistance and drug resistance in cancer.

Erythropoietin-producing hepatocellular A2 (EphA2) is a vital member of the Eph tyrosine kinase receptor family and has been associated with developmental processes. However, it is often overexpressed in tumors and correlates with cancer progression and worse prognosis due to the activation of its noncanonical signaling pathway. Throughout cancer treatment, the emergence of drug-resistant tumor cells is relatively common. Since the early 2000s, researchers have focused on understanding the role of EphA2 in promoting drug resistance in different types of cancer, as well as finding efficient and secure EphA2 inhibitors. In this review, the current knowledge regarding induced resistance by EphA2 in cancer treatment is summarized, and the types of cancer that lead to the most cancer-related deaths are highlighted. Some EphA2 inhibitors were also investigated. Regardless of whether the cancer treatment has reached a drug-resistance stage in EphA2-overexpressing tumors, once EphA2 is involved in cancer progression and aggressiveness, targeting EphA2 is a promising therapeutic strategy, especially in combination with other target-drugs for synergistic effect. For that reason, monoclonal antibodies against EphA2 and inhibitors of this receptor should be investigated for efficacy and drug toxicity.

Exploring the potential of EphA2 receptor signaling pathway: a comprehensive review in cancer treatment.

The protein encoded by the ephrin type-A receptor 2 (EphA2) gene is a member of the ephrin receptor subfamily of the receptor tyrosine kinase family (RTKs). Eph receptors play a significant role in various biological processes, particularly cancer progression, development, and pathogenesis. They have been observed to regulate cancer cell growth, migration, invasion, tumor development, invasiveness, angiogenesis, and metastasis. To target EphA2 activity, various molecular, genetic, biochemical, and pharmacological strategies have been extensively tested in laboratory cultures and animal models. Notably, drugs, such as dasatinib, initially designed to target the kinase family, have demonstrated an additional capability to target EphA2 activity. Additionally, a novel monoclonal antibody named EA5 has emerged as a promising option to counteract the effects of EphA2 overexpression and restore tamoxifen sensitivity in EphA2-transfected MCF-7 cells during in vitro experiments. This antibody mimicked the binding of Ephrin A to EphA2. These methods offer potential avenues for inhibiting EphA2 activity, which could significantly decelerate breast cancer progression and restore sensitivity to certain drugs. This review article comprehensively covers EphA2's involvement in multiple malignancies, including ovarian, colorectal, breast, lung, glioma, and melanoma. Furthermore, we discuss the structure of EphA2, the Eph-Ephrin signaling pathway, various EphA2 inhibitors, and the mechanisms of EphA2 degradation. This article provides an extensive overview of EphA2's vital role in different types of cancers and outlines potential therapeutic approaches to target EphA2, shedding light on the underlying molecular mechanisms that make it an attractive target for cancer treatment.

Potential Role of Nrf2, HER2, and ALDH in Cancer Stem Cells: A Narrative Review.

Cancer is one of the main causes of death among humans, second only to cardiovascular diseases. In recent years, numerous studies have been conducted on the pathophysiology of cancer, and it has been established that this disease is developed by a group of stem cells known as cancer stem cells (CSCs). Thus, cancer is considered a stem cell disease; however, there is no comprehensive consensus about the characteristics of these cells. Several different signaling pathways including Notch, Hedgehog, transforming growth factor-β (TGF-β), and WNT/β-catenin pathways cause the self-renewal of CSCs. CSCs change their metabolic pathways in order to access easy energy. Therefore, one of the key objectives of researchers in cancer treatment is to destroy CSCs. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the protection of CSCs from reactive oxygen species (ROS) and chemotherapeutic agents by regulating antioxidants and detoxification enzymes. Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family, which contributes to the protection of cancer cells against treatment and implicated in the invasion, epithelial-mesenchymal transition (EMT), and tumorigenesis. Aldehyde dehydrogenases (ALDHs) are highly active in CSCs and protect the cells against damage caused by active aldehydes through the regulation of aldehyde metabolism. On the other hand, ALDHs promote the formation and maintenance of tumor cells and lead to drug resistance in tumors through the activation of various signaling pathways, such as the ALDH1A1/HIF-1α/VEGF axis and Wnt/β-catenin, as well as changing the intracellular pH value. Given the growing body of information in this field, in the present narrative review, we attempted to shed light on the function of Nrf2, HER2, and ALDH in CSCs.

Erythropoietin-producing hepatocellular receptor B6 is highly expressed in non-functioning pituitary neuroendocrine tumors and its expression correlates with tumor size

BackgroundErythropoietin-producing hepatocellular (EPH) receptors are the largest known family of receptor tyrosine kinases characterized in humans. These proteins are involved in tissue organization, synaptic plasticity, vascular development and the progression of various diseases including cancer. The Erythropoietin-producing hepatocellular receptor tyrosine kinase member EphB6 is a pseudokinase which has not attracted an equivalent amount of interest as its enzymatically-active counterparts. The aim of this study was to assess the expression of EphB6 in pituitary tumors.Methods and ResultsHuman normal pituitaries and pituitary tumors were examined for EphB6 mRNA expression using real-time PCR and for EphB6 protein by immunohistochemistry and Western blotting. EphB6 was highly expressed in non-functioning pituitary neuroendocrine tumors (NF-PitNETs) versus the normal pituitary and GH-secreting PitNETs. EphB6 mRNA expression was correlated with tumor size.ConclusionsOur results suggest EphB6 aberrant expression in NF-PitNETs. Future studies are warranted to determine the role and significance of EphB6 in NF-PitNETs tumorigenesis.

Anticancer Evaluation of Novel Benzofuran-Indole Hybrids as Epidermal Growth Factor Receptor Inhibitors against Non-Small-Cell Lung Cancer Cells.

The epidermal growth factor receptor (EGFR), also known as ErbB1 and HER1, belongs to the receptor tyrosine kinase family. EGFR serves as the primary driver in non-small-cell lung cancer (NSCLC) and is a promising therapeutic target for NSCLC. In this study, we synthesized a novel chemical library based on a benzofuran-indole hybrid scaffold and identified 8aa as a potent and selective EGFR inhibitor. Interestingly, 8aa not only showed selective anticancer effects against NSCLC cell lines, PC9, and A549, but it also showed significant inhibitory effects against the double mutant L858R/T790M EGFR, which frequently occurs in NSCLC. In addition, in PC9 and A549 cells, 8aa potently blocked the EGFR signaling pathway, cell viability, and cell migration. These findings suggest that 8aa, a benzofuran-indole hybrid derivative, is a novel EGFR inhibitor that may be a potential candidate for the treatment of NSCLC patients with EGFR mutations.