c-Met Research Articles

Novel therapeutic strategies for rare mutations in non-small cell lung cancer

Lung cancer is still the leading cause of cancer-related mortality. Over the past two decades, the management of non-small cell lung cancer (NSCLC) has undergone a significant revolution. Since the first identification of activating mutations in the epidermal growth factor receptor (EGFR) gene in 2004, several genetic aberrations, such as anaplastic lymphoma kinase rearrangements (ALK), neurotrophic tropomyosin receptor kinase (NTRK) and hepatocyte growth factor receptor (MET), have been found. With the development of gene sequencing technology, the development of targeted drugs for rare mutations, such as multikinase inhibitors, has provided new strategies for treating lung cancer patients with rare mutations. Patients who harbor this type of oncologic driver might acquire a greater survival benefit from the use of targeted therapy than from the use of chemotherapy and immunotherapy. To date, more new agents and regimens can achieve satisfactory results in patients with NSCLC. In this review, we focus on recent advances and highlight the new approval of molecular targeted therapy for NSCLC patients with rare oncologic drivers.

A Novel Role for the Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Delta Isoform in Hepatocellular Proliferation

The phosphatidylinositol-4,5-bisphosphate 3-kinase delta isoform (Pik3cd), usually considered immune-specific, was unexpectedly identified as a gene potentially related to either regeneration and/or differentiation in animals lacking hepatocellular Integrin Linked Kinase (ILK). Since a specific inhibitor (Idelalisib, or CAL101) for the catalytic subunit encoded by Pik3cd (p110δ) has reported hepatotoxicity when used for treating Chronic Lymphocytic Leukemia and other lymphomas, we aimed to elucidate if there is a role for p110δ in normal liver function. To determine the effect on normal liver regeneration, partial hepatectomy (PHx) was performed using mice in which p110δ was first inhibited using CAL101. Inhibition led to over a 50% decrease in proliferating hepatocytes in the first two days after PHx. This difference correlated with phosphorylation changes in the HGF and EGF receptors (MET and EGFR, respectively) and NF-κB signaling. Ingenuity Pathway Analyses implicated C/EBPβ, HGF and the EGFR heterodimeric partner, ERBB2, as three of the top 20 regulators downstream of p110δ signaling as their pathways were suppressed in the presence of CAL101 at one day post-PHx. A regulatory role for p110δ signaling in mouse and rat hepatocytes through MET and EGFR was further verified using hepatocyte primary cultures, in the presence or absence of CAL101. Combined, this data supports a role for p110δ as a downstream regulator of normal hepatocytes when stimulated to proliferate.

Abstract PO1-25-03: Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer

Abstract Programmed death-ligand 1 (PD-L1) is an immune checkpoint expressed in a wide range of malignancies leading to immune tolerance and cancer cell immune evasion. Receptor tyrosine kinases (RTKs) are key regulators of cancer cell proliferation, survival, and invasion. The Hepatocyte Growth Factor (HGF) receptor, MET, and the Epidermal Growth Factor Receptor (EGFR) are RTKs known for their tumorigenic potential in a variety of human malignancies. This study aimed to evaluate the effect of the small-molecule tyrosine kinase inhibitors (TKIs) on the expression of PD-L1 in breast cancer cells and the effect of their combination with inflammatory cytokines. The study also assessed the association of the expression of the tumoral PD-L1 mRNA with each of MET and EGFR mRNA expression and the tumor features and treatment outcomes in breast cancer patients using the METABRIC dataset publicly available from cBioPortal for Cancer Genomics. The TKIs crizotinib [a MET inhibitor] and gefitinib [an EGFR inhibitor] were used as a single treatment and in combination with the cytokines; tumor necrosis factor-α (TNF-α) or interferon-γ (INF-γ) in MCF7 and MDA-MB-231 breast cancer cells in vitro. The cells were also treated with the mitogens HGF and EGF. The viability of cells after the different treatments was determined using the MTT viability assay. The effects of the combination treatments were analyzed using combination index (CI) analysis. The expression level of PD-L1 in cancer cells was assessed using Western blotting. The combination treatment of crizotinib with TNF-α and INF-γ produced a synergistic growth inhibition of MCF7 and MDA-MB-231 cells with CI values of 0.31 and 0.55, respectively. Alternatively, combined crizotinib and TNF-α produced an antagonist effect on the viability of MCF7 cells (CI=2.49). The combination of gefitinib with TNF-α produced a synergistic growth inhibition in both MCF7 and MDA-MB-231 cells with CI values of 0.39 and 0.78, respectively. Alternatively, gefitinib resulted in an additive effect when combined with INF-γ (CI=0.99) and an antagonistic effect when combined with TNF-α (CI=2.68) in MCF7 and MDA-MB-231 cells, respectively. Treatment with HGF (50 and 100 ng/ml) increased the protein levels of PD-L1 while EGF (50 and 100 ng/ml) reduced its levels in MDA-MB-231 cells. Treatment with the TKIs crizotinib (0.1-4 µM) and gefitinib (1-40 µM) significantly reduced PD-L1 levels in MDA-MB-231 cells compared to vehicle-treated cells. The analysis of the METABRIC dataset revealed that the mRNA expression of PD-L1 was positively correlated with the mRNA expression of the EGFR gene (r= 0.081, p< 0.001) but not the MET gene. A double-high PD-L1/MET expression was significantly associated with younger age at diagnosis, high-grade carcinoma, greater tumor size, hormone receptor-negative status, HER2-positivity, and non-luminal disease compared to patients with a double-low PD-L1/MET expression. Similar findings were reported for patients with a double-high PD-L1/EGFR expression compared to patients with a double-low PD-L1/EGFR expression. Nevertheless, the mRNA expression of the PD-L1, MET, and EGFR genes as well as the co-expression of PD-L1/MET or PD-L1/EGFR genes did not affect the overall survival of breast cancer patients. Collectively, MET and EGFR TKIs could modulate the effects of inflammatory cytokines differently based on the type of cytokine and the molecular subtype of breast cancer cells. The expression of PD-L1 in breast cancer cells was upregulated by HGF while TKIs reduced its expression. The co-expression of the PD-L1 gene with MET and EGFR genes in breast cancer was associated with advanced disease presentation and worse prognosticators in patients. Together, TKIs that target MET or EGFR could be an appealing therapeutic target in breast cancer, particularly in younger patients with the non-luminal disease. Citation Format: Nehad Ayoub, Muhsen Al-Diabat, Moath Al-Shorman, Laith Al-Eitan. Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in 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 PO1-25-03.

Network Pharmacological Analysis and Experimental Validation of the Effects of Silybin on Proliferation, Migration, and Immunotherapy of Papillary Thyroid Cancer.

The study aimed to use network pharmacology research and in vitro experiments to investigate the material basis and molecular mechanisms of silybin in the treatment of papillary thyroid carcinoma. Papillary thyroid cancer (PTC) has a decent prognosis; however, recurrence and metastasis are the leading causes of death in patients with PTC. A key research focus in thyroid cancer treatment is the inhibition of PTC proliferation, invasion, and migration. Silybin, the major active element in the traditional Chinese herb silymarin, has been used to treat a range of diseases, including cancer, but no study has been undertaken to determine whether it can help prevent PTC. In this study, we attempted to determine through network pharmacology and in vitro experiments if silybin inhibits the development of papillary thyroid cancer by inhibiting cell cycle and invasive migration. To predict the probable targets and underlying mechanisms of silybin against PTC, a network pharmacology research was performed. In vitro experiments were conducted to further evaluate silybin's anti-cancer properties and priority targets against PTC. The datasets revealed a total of 489 silybin targets acting on PTC, and functional enrichment analysis suggested that the target genes were enriched in functions and pathways related to PTC development, invasion, migration, and immunotherapy. By constructing these target PPI networks, the seven hub genes, fibronectin 1 (FN1), tissue inhibitor of metalloproteinases 1 (TIMP1), N-cadherin (CDH2), collagen type III alpha 1 chain (COL3A1), cyclin D1 (CCND1), AP-1 transcription factor subunit (JUN), and hepatocyte growth factor receptor (MET) were found. These hub genes were determined to be highly linked to a worse clinicopathological form, a higher risk of metastatic recurrence, and a worse prognosis of PTC. The common immunological checkpoint gene expression levels were positively correlated with the expression levels of the hub genes. Silybin decreased the proliferative and metastatic capacity of PTC cells, according to in vitro investigations. When PTC was treated with silybin, the FN1/AKT signaling pathway was blocked, CCND1 expression was reduced, and CDH2, Vimentin, Snail, Slug and PD-L1 expressions were dramatically reduced, while E-cadherin expression was significantly elevated. These findings provide preliminary evidence that silybin inhibits PTC cell proliferation, metastasis, and invasion by altering the FN1/AKT signaling pathway and inhibiting the EMT process. Silybin can reverse immunosuppression in papillary thyroid cancer by affecting immunological checkpoint gene expression levels. These studies provide a theoretical and experimental scientific basis for the potential anticancer effects of silybin on PTC.

Identification of endophenotypes supporting outcome prediction in hemodialysis patients based on mechanistic markers of statin treatment

BackgroundStatins are widely used to reduce the risk of cardiovascular disease (CVD). Patients with end-stage renal disease (ESRD) on hemodialysis have significantly increased risk of developing CVD. Statin treatment in these patients however did not show a statistically significant benefit in large trials on a patient cohort level. MethodsWe generated gene expression profiles for statins to investigate the impact on cellular programs in human renal proximal tubular cells and mesangial cells in-vitro. We subsequently selected biomarkers from key statin-affected molecular pathways and assessed these biomarkers in plasma samples from the AURORA cohort, a double-blind, randomized, multi-center study of patients on hemodialysis or hemofiltration that have been treated with rosuvastatin. Patient clusters (phenotypes) were created based on the identified biomarkers using Latent Class Model clustering and the associations with outcome for the generated phenotypes were assessed using Cox proportional hazards regression models. The multivariable models were adjusted for clinical and biological covariates based on previously published data in AURORA. ResultsThe impact of statin treatment on mesangial cells was larger as compared with tubular cells with a large overlap of differentially expressed genes identified for atorvastatin and rosuvastatin indicating a predominant drug class effect. Affected molecular pathways included TGFB-, TNF-, and MAPK-signaling and focal adhesion among others. Four patient clusters were identified based on the baseline plasma concentrations of the eight biomarkers. Phenotype 1 was characterized by low to medium levels of the hepatocyte growth factor (HGF) and high levels of interleukin 6 (IL6) or matrix metalloproteinase 2 (MMP2) and it was significantly associated with outcome showing increased risk of developing major adverse cardiovascular events (MACE) or cardiovascular death. Phenotype 2 had high HGF but low Fas cell surface death receptor (FAS) levels and it was associated with significantly better outcome at 1 year. ConclusionsIn this translational study, we identified patient subgroups based on mechanistic markers of statin therapy that are associated with disease outcome in patients on hemodialysis.

Betaglycan sustains HGF/Met signaling in lung cancer and endothelial cells promoting cell migration and tumor growth

Persistent HGF/Met signaling drives tumor growth and dissemination. Proteoglycans within the tumor microenvironment might control HGF availability and signaling by affecting its accessibility to Met (HGF receptor), likely defining whether acute or sustained HGF/Met signaling cues take place. Given that betaglycan (BG, also known as type III TGFβ receptor or TGFBR3), a multi-faceted proteoglycan TGFβ co-receptor, can be found within the tumor microenvironment, we addressed its hypothetical role in oncogenic HGF signaling. We found that HGF/Met promotes lung cancer and endothelial cells migration via PI3K and mTOR. This effect was enhanced by recombinant soluble betaglycan (solBG) via a mechanism attributable to its glycosaminoglycan chains, as a mutant without them did not modulate HGF effects. Moreover, soluble betaglycan extended the effect of HGF-induced phosphorylation of Met, Akt, and Erk, and membrane recruitment of the RhoGEF P-Rex1. Data-mining analysis of lung cancer patient datasets revealed a significant correlation between high MET receptor, HGF, and PREX1 expression and reduced patient survival. Soluble betaglycan showed biochemical interaction with HGF and, together, they increased tumor growth in immunocompetent mice. In conclusion, the oncogenic properties of the HGF/Met pathway are enhanced and sustained by GAG-containing soluble betaglycan.

Activating Point Mutations in the MET Kinase Domain Represent a Unique Molecular Subset of Lung Cancer and Other Malignancies Targetable with MET Inhibitors.

Activating point mutations in the MET tyrosine kinase domain (TKD) are oncogenic in a subset of papillary renal cell carcinomas. Here, using comprehensive genomic profiling among >600,000 patients, we identify activating MET TKD point mutations as putative oncogenic driver across diverse cancers, with a frequency of ∼0.5%. The most common mutations in the MET TKD defined as oncogenic or likely oncogenic according to OncoKB resulted in amino acid substitutions at positions H1094, L1195, F1200, D1228, Y1230, M1250, and others. Preclinical modeling of these alterations confirmed their oncogenic potential and also demonstrated differential patterns of sensitivity to type I and type II MET inhibitors. Two patients with metastatic lung adenocarcinoma harboring MET TKD mutations (H1094Y, F1200I) and no other known oncogenic drivers achieved confirmed partial responses to a type I MET inhibitor. Activating MET TKD mutations occur in multiple malignancies and may confer clinical sensitivity to currently available MET inhibitors. Significance: The identification of targetable genomic subsets of cancer has revolutionized precision oncology and offers patients treatments with more selective and effective agents. Here, we demonstrate that activating, oncogenic MET tyrosine kinase domain mutations are found across a diversity of cancer types and are responsive to MET tyrosine kinase inhibitors.

The Combination of Afatinib With Dasatinib or Miransertib Results in Synergistic Growth Inhibition of Stomach Cancer Cells.

Of various human epidermal growth factor receptor (HER) inhibitors, only the anti-HER2 monoclonal antibody (mAb) Herceptin/trastuzumab and the antibody-drug conjugate trastuzumab deruxtecan (T-Dxd) has been approved for the treatment of patients with stomach cancer. However, the duration of response may be short in many patients, with tumor heterogeneity being one contributing factor. We investigated the effect of various types of targeted agents on growth in vitro and migration of a panel of human stomach cancer cells (HSCCLs) and the impact of cell proliferation rate on the anti-tumor activities of these agents. We also investigated the association between the cell surface expression of the HER family members, hepatocyte growth factor receptor (c-Met), anaplastic lymphoma kinase (ALK)7 and cancer stem cell markers CD44 and CD133, and the response to the targeted agents. Of the 18 agents examined, the cyclin dependent kinase (CDK) 1/2/5/9 inhibitor dinaciclib was the most effective and inhibited the growth of all human HSCCLs at 50% inhibitory concentration (IC50) values between 9 nM to 23 nM. Of various HER inhibitors, the irreversible pan-HER family inhibitors (e.g., afatinib) were more effective than the reversible dual epidermal growth factor receptor (EGFR)/HER2 tyrosine kinase inhibitor (TKI) lapatinib and the EGFR-specific TKI erlotinib in inhibiting the growth of HSCCLs. Of agents targeting different downstream cell signaling molecules, dasatinib targeting Ab1/Src/C-Kit, trametinib targeting MERK1/2 and miransertib targeting AKT1/2/3 inhibited growth of majority of HSCCLs, with the IC50 values ranging from 2 nM to 7 µM. Many of these agents were more effective in inhibiting the growth of HSCCLs when they were proliferating at a slower rate. Treatment with neratinib, afatinib, dinaciclib, dasatinib, stattic, miransertib and paclitaxel significantly inhibited migration of stomach cancer cells. Interestingly, treatment with a combination of afatinib and dasatinib or afatinib and miransertib resulted in synergistic and additive growth inhibition of stomach cancer cells. These results suggest that treatment with a combination of these agents may be of therapeutic value in stomach cancer and warrants further investigations.

Enhanced phototoxicity and specificity of AlPCS4 when loaded in liposomes conjugated with a MET-targeting nanobody

SignificancePhotodynamic therapy (PDT) improves the survival of cholangiocarcinoma patients. Here, to improve the pharmacokinetics and efficacy of PDT, AlPCS4 was encapsulated into liposomes conjugated with a nanobody. ApproachAlPCS4 was loaded in liposomes conjugated with a nanobody targeting hepatocyte growth factor receptor (MET). The uptake of the MET-targeted liposomes (MET-TLs) and non-targeted liposomes (NTLs) was studied with confocal microscopy and flow-cytometry. Phototoxicity of MET-TLs and NTLs was tested by exposing MET-positive (TOV+MET, EGI1) and MET-negative (TOV112D) cells to a range of AlPCS4 concentrations. After incubation, cells were illuminated and cell viability was measured with MTS assay. ResultsMET-TLs were more internalized by MET-positive cells and induced higher phototoxicity than NTLs (LC50 was 10 × lower for MET-TLs). No phototoxicity was observed on MET-negative cells and in non-illuminated controls for the concentrations tested. ConclusionsThis study demonstrated that MET-TLs can increase the specificity of AlPCS4 towards cancer cells and enhance phototoxicity.

The MET Oncogene: Thirty Years of Insights into Molecular Mechanisms Driving Malignancy.

The discovery and subsequent research on the MET oncogene's role in cancer onset and progression have illuminated crucial insights into the molecular mechanisms driving malignancy. The identification of MET as the hepatocyte growth factor (HGF) receptor has paved the path for characterizing the MET tyrosine kinase activation mechanism and its downstream signaling cascade. Over the past thirty years, research has established the importance of HGF/MET signaling in normal cellular processes, such as cell dissociation, migration, proliferation, and cell survival. Notably, genetic alterations that lead to the continuous activation of MET, known as constitutive activation, have been identified as oncogenic drivers in various cancers. The genetic lesions affecting MET, such as exon skipping, gene amplification, and gene rearrangements, provide valuable targets for therapeutic intervention. Moreover, the implications of MET as a resistance mechanism to targeted therapies emphasize the need for combination treatments that include MET inhibitors. The intriguing "flare effect" phenomenon, wherein MET inhibition can lead to post-treatment increases in cancer cell proliferation, underscores the dynamic nature of cancer therapeutics. In human tumors, increased protein expression often occurs without gene amplification. Various mechanisms may cause an overexpression: transcriptional upregulation induced by other oncogenes; environmental factors (such as hypoxia or radiation); or substances produced by the reactive stroma, such as inflammatory cytokines, pro-angiogenic factors, and even HGF itself. In conclusion, the journey to understanding MET's involvement in cancer onset and progression over the past three decades has not only deepened our knowledge, but has also paved the way for innovative therapeutic strategies. Selective pharmacological inactivation of MET stands as a promising avenue for achieving cancer remission, particularly in cases where MET alterations are the primary drivers of malignancy.

Therapeutic potential of tyrosine-protein kinase MET in osteosarcoma.

Osteosarcoma, the most prevalent primary bone tumor in children and young adults, can often be successfully treated with standard chemotherapy and surgery when diagnosed at an early stage. However, patients presenting with metastases face significant challenges in achieving a cure. Despite advancements in classical therapies over the past few decades, clinical outcomes for osteosarcoma have not substantially improved. Recently, there has been increased understanding of the biology of osteosarcoma, leading to the identification of new therapeutic targets. One such target is MET, a tyrosine kinase receptor for Hepatocyte Growth Factor (HGF) encoded by the MET gene. In vitro and in vivo studies have demonstrated that the HGF/MET pathway plays a crucial role in cancer growth, invasion, metastasis, and drug resistance across various cancers. Clinical trials targeting this pathway are already underway for lung cancer and hepatocellular carcinoma. Moreover, MET has also been implicated in promoting osteosarcoma progression. This review summarizes 3decades' worth of research on MET's involvement in osteosarcoma and further explores its potential as a therapeutic target for patients with this disease.

Abstract 597: Vebreltinib: A novel brain-penetrating MET kinase inhibitor demonstrates the mechanism of action and pharmacological anti-tumor activity in diverse patient-derived MET-dysregulated tumor models at clinically relevant drug levels

Abstract Background: Dysregulation of the MET signaling pathway drives oncogenesis in many human cancers, the majority of which have not been addressed by a MET targeted therapy albeit the emerging therapies for MET exon 14 skipping (MET ex14) NSCLC. We have developed a novel highly selective MET kinase inhibitor vebreltinib (APL-101, PLB1001, bozitinib) to address unmet medical need. Vebreltinib is being jointly investigated in ongoing pivotal Phase 2 and 2/3 studies in MET-dysregulated NSCLC, primary CNS cancers and basket solid tumors in China (as PLB-1001) and globally ex-China (as APL-101). The Phase 1 portion of both studies have been concluded with the same RP2D (200 mg BID by oral administration). Vebreltinib demonstrated blood-brain barrier permeability in PLB-1001 Phase 1 glioblastoma study as previously reported. Methods: MET enzyme kinetics and vebreltinib intrinsic potency were studied by a radiometric MET kinase assay. Selectivity was profiled by in vitro KINOME. Vebreltinib cellular activity on MET signaling and in vivo anti-tumor activity were assessed in tumor cell lines and patient-derived tumors (PDX) carrying MET alterations. Results: Vebreltinib is an ATP-competitive inhibitor with Ki of approximately 2.2 nM for recombinant MET kinase and inhibited the native form of activated MET with 0.52 nM IC50. Vebreltinib demonstrated exquisite selectivity in KINOMEscan selectivity panel. Vebreltinib inhibited HGF-dependent and -independent MET signaling in KP4 tumor cell lines with nanomolar concentrations. Vebreltinib inhibited IL-3 independent Ba/F3 cell lines carrying exogenous MET ex14 or with secondary mutations induced by other MET TKIs. Vebreltinib inhibited MKN45 gastric tumor xenograft in vivo with ED90 of 6 mg/kg PO/QD. Furthermore, Vebreltinib demonstrated strong anti-tumor activity in a variety of PDX tumor types carrying MET ex14, MET fusions, and MET amplification. In these preclinical studies, the total and unbound vebreltinib plasma concentration observed at steady state trough of RP2D was used as a clinically relevant drug level to interpret Vebreltinib efficacy in blocking oncogenic MET signaling, proliferation of Ba/F3 cell lines with a broad spectrum of MET mutations and in vivo tumor growth in PDXs carrying diverse MET alterations. We demonstrated the rationale for Vebreltinib to be an efficacious single-agent MET inhibitor in treating tumors carrying MET driver alterations beyond MET ex14 NSCLC. Conclusion: Vebreltinib is a novel potent MET kinase inhibitor showing promising preclinical activity against PDXs from diverse organs sites and genomic alterations such as MET ex14, MET fusion, MET amplification, or HGF over-expression at clinically relevant drug levels, providing proof-of-concepts for continued clinical development. Citation Format: Xiaoling Zhang, Elaine Liu, Yan Song, Peony Yu, Sanjeev Redkar, Guo-Liang Yu. Vebreltinib: A novel brain-penetrating MET kinase inhibitor demonstrates the mechanism of action and pharmacological anti-tumor activity in diverse patient-derived MET-dysregulated tumor models at clinically relevant drug levels [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 597.

Abstract 7195: Repurposing non-oncology drugs with MET inhibitory effect to overcome osimertinib resistance in lung cancer

Abstract Background and Aim: Osimertinib is the only 3rd generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor approved for the 1st line therapy of advanced NSCLC patients with EGFR mutations. However, drug resistance is severely limiting its clinical efficacy. Aberrant MET activation is an important mechanism causing osimertinib resistance. There is no effective therapeutic option after osimertinib failure. This study investigated the repurposing of non-oncology MET inhibiting drug to overcome osimertinib resistance. Method: A few clinically-approved drugs with putative MET inhibitory effects were identified by a computational drug repurposing tool called “DRAR-CPI” via analysis of the chemical-protein interactome of known MET inhibitors (crizotinib, cabozantinib, foretinib, and tivantinib). Fexofenadine (FEX), originally indicated for allergic rhinitis and chronic urticaria, was chosen for detailed investigation in osimertinib-resistant NSCLC cell lines that exhibit aberrant MET activation with/without other EGFR-dependent osimertinib resistance mechanisms. The selectivity of kinase inhibition by FEX was evaluated by a KINOME profiling assay against a panel of human protein kinases. Western blot analysis was conducted to examine the activation status of Met and EGFR downstream signaling. RNA sequencing was performed to identify differentially expressed genes (DEGs) triggered by the most promising repurposed drug, presumably contributing to osimertinib resistance circumvention. Sulforhodamine B assay was used to evaluate cell proliferation. The circumvention of osimertinib resistance by FEX was further verified in a patient-derived tumor xenograft (PDX) from an advanced-stage osimertinib-refractory NSCLC patient. Result: FEX was found to inhibit recombinant MET kinase in cell-free assays in a dose- and time-dependent manner. It also inhibited MET phosphorylation and other downstream signaling molecules in osimertinib-resistant NSCLC cell lines harboring EGFR T790M+MET amplification or EGFR T790M loss+MET amplification. KINOME profiling revealed a similar kinase inhibition profile between FEX and cabozantinib using Spearman rank order correlation analysis. Among the tested osimertinib-resistant NSCLC cell lines, FEX showed the highest effectiveness in potentiating the anticancer effect of osimertinib in H820 cells (having MET amplification & EGFR T790M mutation). Transcriptome profiling analysis in H820 cells before and after FEX treatment revealed that the majority of DEGs were enriched in EMT-related biological processes and pathways. FEX was further shown to significantly potentiate the antitumor effect of osimertinib in a drug refractory PDX model, without inducing notable weight loss in the animals. Conclusion: These findings advocate the clinical evaluation of repurposing FEX to overcome osimertinib resistance. Citation Format: Kenneth K.W. To, Kwong Sak Leung, William C.S. Cho. Repurposing non-oncology drugs with MET inhibitory effect to overcome osimertinib resistance in lung 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 7195.

Abstract 6500: Dependence of EGFR-mutant NSCLC on MET as demonstrated by vebreltinib, a novel and selective brain-penetrating MET kinase inhibitor

Abstract Background: Although EGFR inhibitors (EGFRi), preferably osimertinib, have offered substantial benefit for the classical plus T790M EGFR-mutant NSCLC patients, drug resistance develops and poses a critical challenge for long-term survival. The resistance is rooted to either on-target secondary EGFR mutations or compensatory oncogenic pathways bypassing EGFRi intervention, one of which appears to be treatment-acquired MET amplification (METamp). In this study we set out to understand the conditions when the tumor cells become dependent on MET. Methods: NSCLC patient-derived tumor models (PDX) carrying classical and T790M EGFR driver mutations were selected based on EGFRi history and concurrent MET gene copy numbers or RNA expression levels: Type 1) resistant to osimertinib with METamp; Type 2) partially resistant to osimertinib with METamp; and Type 3) sensitive to osimertinib with low MET expression, no METamp. These PDX xenograft mice were treated with vebreltinib (APL-101) at clinically relevant doses as single agent or in combination with osimertinib. The pharmacodynamic effects on EGFR and MET phosphor (P)- and total proteins were analyzed from tumor samples harvested during and at the end of treatments. Results: Vebreltinib single agent inhibited tumor growth of the type-1 PDX. One such PDX was resistant to chemotherapies, BRAF inhibitor and EGFRi including osimertinib, was inhibited by vebreltinib with ED50 of 3 mg/kg (p.o/q.d.). Another such PDX tumor appeared to be eradicated by vebreltinib treatment at 10 mg/kg (p.o/q.d.) and the mice became tumor-free on Day 18 and remained so after dosing stop on day 21 with last observation at study end (Day 70). In comparison, reference METi savolitinib showed only partial tumor size reduction against the same PDX tumor, not as durable as vebreltinib, and did not eradicate tumor growth at the same dose as vebreltinib or in combo with Osimertinib. Re-grown tumor after savolitinib osimertinib combo dosing stop was inhibited completely by vebreltinib follow-on treatment. In the type-2 PDX, tumor growth was partially inhibited by vebreltinib but was completely inhibited by combo of vebreltinib and osimertinib. The anti-tumor activity of vebreltinib in type-1 and type-2 PDX was associated with pharmacodynamic inhibition of P-MET and P-EGFR and MET protein degradation. In the type-3 PDX, tumor growth appeared to be eradicated by osimertinib and not inhibited by vebreltinib. However, addition of vebreltinib suppressed tumor re-growth after osimertinib dosing stop. Conclusion: EGFR-mutant NSCLC resistance to EGFRi may be dependent on MET pathway regardless of acquired METamp, whereas METamp may dictate the degree of MET dependence. Our data supports the hypothesis that adding vebreltinib to EGFRi overcome MET dependent resistance with durable effect or preventing MET dependent resistance to maximize therapeutic benefits. Citation Format: Xiaoling Zhang, Elaine Liu, Yan Song, Peony Yu, Sanjeev Redkar, Guo-Liang Yu. Dependence of EGFR-mutant NSCLC on MET as demonstrated by vebreltinib, a novel and selective brain-penetrating MET kinase inhibitor [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 6500.

Nanobody-mediated targeting of zinc phthalocyanine with polymer micelles as nanocarriers

Photodynamic therapy (PDT) is a suitable alternative to currently employed cancer treatments. However, the hydrophobicity of most photosensitizers (e.g., zinc phthalocyanine (ZnPC)) leads to their aggregation in blood. Moreover, non-specific accumulation in skin and low clearance rate of ZnPC leads to long-lasting skin photosensitization, forcing patients with a short life expectancy to remain indoors. Consequently, the clinical implementation of these photosensitizers is limited. Here, benzyl-poly(ε-caprolactone)-b-poly(ethylene glycol) micelles encapsulating ZnPC (ZnPC-M) were investigated to increase the solubility of ZnPC and its specificity towards cancers cells. Asymmetric flow field-flow fractionation was used to characterize micelles with different ZnPC-to-polymer ratios and their stability in human plasma. The ZnPC-M with the lowest payload (0.2 and 0.4% ZnPC w/w) were the most stable in plasma, exhibiting minimal ZnPC transfer to lipoproteins, and induced the highest phototoxicity in three cancer cell lines. Nanobodies (Nbs) with binding specificity towards hepatocyte growth factor receptor (MET) or epidermal growth factor receptor (EGFR) were conjugated to ZnPC-M to facilitate cell targeting and internalization. MET- and EGFR-targeting micelles enhanced the association and the phototoxicity in cells expressing the target receptor. Altogether, these results indicate that ZnPC-M decorated with Nbs targeting overexpressed proteins on cancer cells may provide a better alternative to currently approved formulations.

Design, synthesis, and biological evaluation of new biaryl derivatives of cycloalkyl diacetamide bearing chalcone moiety as type II c-MET kinase inhibitors.

Many human cancers have been associated with the deregulation of the mesenchymal-epithelial transition factor tyrosine kinase (MET) receptor, a promising drug target for anticancer drug discovery. Herein, we report the discovery of a novel structure of potent chalcone-based derivatives type II c-Met inhibitors which are comparable to Foretinib (IC50 = 14 nM) as a potent reference drug. Based on our design strategy, we also expected an anti-tubulin activity for the compounds. However, the weak inhibitory effects on microtubules were confirmed by cell cycle analyses implicated that the observed cytotoxicity against HeLa cells probably was not derived from tubulin inhibition. Compounds 14q and 14k with IC50 values of 24 nM and 45 nM, respectively, demonstrated favorable inhibition of MET kinase activity, and desirable bonding interactions in the ligand-MET enzyme complex stability in molecular docking studies.

Regeneration of Non-Alcoholic Fatty Liver Cells Using Chimeric FGF21/HGFR: A Novel Therapeutic Approach.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a significant liver ailment attributed to factors like obesity and diabetes. While ongoing research explores treatments for NAFLD, further investigation is imperative to address this escalating health concern. NAFLD manifests as hepatic steatosis, precipitating insulin resistance and metabolic syndrome. This study aims to validate the regenerative potential of chimeric fibroblast growth factor 21 (FGF21) and Hepatocyte Growth Factor Receptor (HGFR) in NAFLD-afflicted liver cells. AML12, a murine hepatocyte cell line, was utilized to gauge the regenerative effects of chimeric FGF21/HGFR expression. Polysaccharide accumulation was affirmed through Periodic acid-Schiff (PAS) staining, while LDL uptake was microscopically observed with labeled LDL. The expression of FGF21/HGFR and NAFLD markers was analyzed by mRNA analysis with RT-PCR, which showed a decreased expression in acetyl-CoA carboxylase 1 (ACC1) and sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) with increased expression of hepatocellular growth factor (HGF), hepatocellular nuclear factor 4 alpha (HNF4A), and albumin (ALB). These findings affirm the hepato-regenerative properties of chimeric FGF21/HGFR within AML12 cells, opening novel avenues for therapeutic exploration in NAFLD.

Identify novel inflammation-related prognostic signature in pancreatic cancer patients.

Pancreatic cancer (PC) is a malignant tumor of the digestive system with a poor prognosis. PC patients with pancreatitis have a worse prognosis. But nobody reported the relationship between inflammation and prognosis in PC. Based on this, we are going to explore inflammation-related prognostic signature to predict patients' survival and potential therapeutic target. We screened gene expression profile and corresponding clinical information of patients from The Cancer Genome Atlas (TCGA) database. Gene set enrichment analysis (GSEA) was performed to identify differentially expressed genes (DEGs) between tumor and normal tissues with P value < .05. Univariate and multivariate Cox regression analysis was applied to identify possible prognostic inflammation genes and establish an inflammation-related risk score system, which was validated by Kaplan-Meier and Receiver operating characteristic (ROC) curves. Finally, we used the TISIDB database to predict targeted drugs for up-regulated gene hepatocyte growth factor receptor (MET) and used AUTODOCK software for molecular docking. We built a prognostic model consisted of 3 inflammation-related genes (tumor necrosis factor receptor associated factor 1/TFAR1, tyrosine kinase 2/TYK2, MET). According to the median value of those genes' risk score, PC patients were ranked into high- (88) and low-risk (89) groups. Then, the results of the Kaplan-Meier curves and the area under the curve (AUC) of the ROC curves showed this model had a good predictive power (P < .001, AUC = 0.806). The result of human protein atlas (HPA) database showed the expression of TRAF1 and TYK2 were low in pancreatic cancer, the expression of MET was high. TISIDB database founded brigatinib could target to MET. And AUTODOCK showed brigatinib had a nice docking with MET. Taken together, our study suggested that inflammation-associated prognostic signature might be used as novel biomarkers for predicting prognosis in PC patients and potential therapeutic target of the disease.

Phosphoglycerate kinase 1 acts as a cargo adaptor to promote EGFR transport to the lysosome

The epidermal growth factor receptor (EGFR) plays important roles in multiple cellular events, including growth, differentiation, and motility. A major mechanism of downregulating EGFR function involves its endocytic transport to the lysosome. Sorting of proteins into intracellular pathways involves cargo adaptors recognizing sorting signals on cargo proteins. A dileucine-based sorting signal has been identified previously for the sorting of endosomal EGFR to the lysosome, but a cargo adaptor that recognizes this signal remains unknown. Here, we find that phosphoglycerate kinase 1 (PGK1) is recruited to endosomal membrane upon its phosphorylation, where it binds to the dileucine sorting signal in EGFR to promote the lysosomal transport of this receptor. We also elucidate two mechanisms that act in concert to promote PGK1 recruitment to endosomal membrane, a lipid-based mechanism that involves phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and a protein-based mechanism that involves hepatocyte growth factor receptor substrate (Hrs). These findings reveal an unexpected function for a metabolic enzyme and advance the mechanistic understanding of how EGFR is transported to the lysosome.

Quantification and clinical validation of the selective MET kinase inhibitor DO-2 and its metabolites DO-5 and M3 in human plasma

DO-2 is a highly selective MNNG HOS transforming (MET) inhibitor. This deuterated drug is thought to diminish the formation of the Aldehyde Oxidase 1 inactive metabolite M3. For various reasons, quantification of DO-2 and its metabolites M3 and DO-5 is highly relevant. In this study, we present an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to quantify DO-2, M3 and DO-5. Rolipram served as the internal standard. Aliquots of 25 µL were mixed with 100 µL internal standard consisting of 10 ng/mL rolipram in acetonitrile. Separation of the analytes was achieved on an Acquity UPLC ® HSS T3 column, utilizing gradient elution with water/formic acid and acetonitrile/formic acid at a flow-rate of 0.400 mL/min. Calibration curves were linear in the range of 1.00 – 1000 ng/mL for DO-2 and DO-5, and 2.00 – 2000 ng/mL for M3 in human plasma. The within-run and between-run precisions of DO-2, DO-5 and M3, also at the level of the LLQ, were within 12.1%, while the accuracy ranged from 89.5 to 108.7%. All values for accuracy, within-run and between-run precisions met the criteria set by the Food and Drug Administration. The method was effectively employed in the analysis of samples obtained from a clinical trial.