Synergism of EGFR and c-Met pathways, cross-talk and inhibition, in non-small cell lung cancer

The User's Guide to Amivantamab

Targeted therapies have revolutionized treatment of non-small-cell lung cancer (NSCLC); however, epidermal growth factor receptor (EGFR) exon20ins mutations are resistant to tyrosine kinase inhibitors. Amivantamab utilizes multiple mechanisms of action to bypass the altered binding site conformation and recruits immune cells for anti-cancer activity. Amivantamab is approved in the frontline setting of EGFR exon20ins-mutated NSCLC in combination with carboplatin plus pemetrexed. Single-agent amivantamab is approved in second line or later for EGFR exon20ins. Furthermore, amivantamab with lazertinib for first line as well as amivantamab in combination with carboplatin and pemetrexed for second line after osimertinib have both been approved in the treatment of NSCLC harboring EGFR-sensitizing mutations. Now with multiple indications, we must learn how to manage the unique side effects of amivantamab to maximize treatment benefit for the patients. Side effects of amivantamab can be associated with inhibition of the EGFR and/or mesenchymal epithelial transcription factor (MET) signaling pathways. This work reviews the mechanism of action, pharmacology, clinical trial data, and covers management of toxicities. This guide is designed as a practical reference tool for clinicians, pharmacists, and basic science researchers.

Advances in the selective c-MET kinase inhibitors: Application of fused [5,6]-Bicyclic nitrogen-containing cores for anticancer drug design

Over the past two decades, small molecules bearing [5,6]-bicyclic nitrogen-containing cores have emerged as one of the most extensively studied structures for the development of selective c-MET kinase inhibitors. Structure-activity relationship (SAR) studies have demonstrated that modifying these cores can significantly impact the biological properties of c-MET inhibitors, including safety/toxicity, potency, and metabolic stability. For example, although c-MET kinase inhibitors containing the [1,2,4]triazolo[4,3-b][1,2,4]triazine scaffold (core P) exhibit high inhibitory potency, they often face challenges due to metabolic stability defects. Alternatively, compounds containing [1,2,3]triazolo[4,5-b]pyrazine (core K) and [1,2,4]triazolo[4,3-b]pyridazine (core I) scaffolds demonstrate lower potency but improved metabolic stability, allowing some of them to progress into clinical trials and even be approved as novel anticancer drugs. Fortunately, X-ray crystallography studies have well elucidated key interactions between [5,6]-bicyclic nitrogen-containing cores and crucial amino acid residues within the c-MET active site. These insights emphasize the significance of π-π stacking interactions with Tyr1230 and hydrogen bonding with Asp1222, providing valuable guidance for the targeted design and optimization of selective c-MET kinase inhibitors. Following the identification/introduction of sixteen distinct [5,6]-bicyclic nitrogen-containing cores (cores A-P) utilized in the design of selective c-MET kinase inhibitors over the past two decades, this manuscript offers a comprehensive review of their roles in drug development of anticancer agents, and describes the various synthesis methods employed. The insights presented herein can serve as a resource for better structural optimization of c-MET kinase inhibitors in the future research.

EGFR and PI3K Signalling Pathways as Promising Targets on Circulating Tumour Cells from Patients with Metastatic Gastric Adenocarcinoma

The prognosis for metastatic gastric adenocarcinoma (mGAC) remains poor. Gene alterations in receptor tyrosine kinases (RTKs) such as epidermal growth factor receptor (EGFR) and their downstream effectors including catalytic subunit alpha of the phosphatidylinositol 3-kinase (PIK3CA) are common in mGAC. Targeted RTK and phosphatidylinositol-3-kinase (PI3K) treatments have demonstrated clinical benefits in other solid tumours and are key potential targets for clinical development against mGAC given the presence of recurrent alterations in these pathways. Furthermore, combination RTK/PI3K treatments may overcome compensatory mechanisms that arise using monotherapies, leading to improved patient outcomes. Herein, we investigated RTK/PI3K single and combination drug responses against our unique human mGAC-derived PIK3CA gain-of-function mutant, human epidermal growth factor receptor 2 (HER2)-negative, EGFR-expressing circulating tumour cell line, UWG02CTC, under two- and three-dimensional culture conditions to model different stages of metastasis. UWG02CTCs were highly responsive to the PI3K p110α-subunit targeted drugs PIK-75 (IC50 = 37.0 ± 11.1 nM) or alpelisib (7.05 ± 3.7 µM). Drug sensitivities were significantly increased in 3D conditions. Compensatory MAPK/ERK pathway upregulation by PI3K/Akt suppression was overcome by combination treatment with the EGFR inhibitor gefitinib, which was strongly synergistic. PIK-75 plus gefitinib significantly impaired UWG02CTC invasion in an organotypic assay. In conclusion, UWG02CTCs are a powerful ex vivo mGAC drug responsiveness model revealing EGFR/PI3K-targeted drugs as a promising combination treatment option for HER2-negative, RAS wild-type mGAC patients.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

Design, synthesis, and biological evaluation of 4-(2-fluorophenoxy)-7-methoxyquinazoline derivatives as dual EGFR/c-Met inhibitors for the treatment of NSCLC

In non-small cell lung cancer (NSCLC) treatment, aberrant expression of c-mesenchymal-epithelial transition factor (c-Met) has been identified as a driving factor in epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance. Unfortunately, none of the EGFR/c-Met dual-target inhibitors have successfully passed clinical trials. Hence, based on molecular docking analysis and combination principles of EGFR and c-Met inhibitors, three series of 4-(2-fluorophenoxy)-7-methoxyquinazoline derivatives as new EGFR/c-Met inhibitors were designed, synthesized, and evaluated for their biological activities. Among these compounds, TS-41 displayed the best inhibitory activity against EGFRL858R and c-Met kinases, with an IC50 value of 68.1 nM and 0.26 nM respectively. Moreover, it also showed excellent inhibitory activity on three NSCLC cell lines A549-P, H1975 and PC-9 with IC50 values ranging from 1.48 to 2.76 μM. Flow cytometry assays demonstrated that TS-41 induced apoptosis and cell cycle arrest of A549-P cells in a concentration-dependent manner, corresponding to JC-1 staining assay results. Western blot analysis revealed that TS-41 significantly downregulated the phosphorylation of EGFR, c-Met, and downstream AKT at molecular level. Importantly, TS-41 exhibited potent in vivo anticancer efficacy in an A549-P-bearing allograft nude mouse model at a dose of 60 mg/kg with a tumor growth inhibition rate of 55.3 % compared with Afatinib (46.4 %), as well as low hemolytic toxicity and organ toxicity. Molecular docking results showed that TS-41 was well embedded into the cavity of EGFR (PDB: 5GMP) and c-Met (PDB: 3LQ8) proteins, respectively. In summary, TS-41 is a high-efficiency and low-toxicity EGFR/c-Met inhibitor for the treatment of NSCLC and is worthy of further exploration.

Clinical Implication of Concurrent Amplification of MET and FGFR2 in Metastatic Gastric Cancer

BACKGROUND

c-mesenchymal epithelial transition factor receptor (c-MET) and fibroblast growth factor receptor 2 (FGFR2) amplification have been identified as factors associated with advanced stage and poor prognosis in gastric cancer (GC). While they are typically considered mutually exclusive, concurrent amplifications have been reported in a small subset of GC patients.

METHODS

in this retrospective study, we analyzed the clinical outcomes of GC patients with MET and FGFR2 amplification using the next-generation sequencing (NGS) database cohort at Samsung Medical Center, which included a total of 2119 patients between October 2019 and April 2021.

RESULTS

Of 2119 cancer patients surveyed, the number of GC patients was 614 (29.0%). Out of 614 GC patients, 39 (6.4%) had FGFR2 amplification alone, 22 (3.6%) had MET amplification, and 2 GC patients (0.3%) had concurrent FGFR2 and MET amplification. Two patients with concurrent FGFR2 and MET amplification did not respond to first-line chemotherapy. These two patients had significantly shorter overall survival (3.6 months) compared to patients with FGFR2 or MET amplification alone (13.6 months and 8.4 months, respectively) (p = 0.004). Lastly, we tested the existence of FGFR2 and MET in tumor specimens from different organ sites. Initially, the NGS was tested in a primary tumor specimen from stomach cancer, where the MET copy number was 14.1 and the FGFR2 copy number was 5.3. We confirmed that both MET and FGFR2 were highly amplified in the primary tumor using FISH (MET-CEP7 ratio = 5 and FGFR2-CEP7 ratio = 3). However, although the MET copy number was normal in peritoneal seeding using FISH, FGFR2 remained amplified using FISH (FGFR2-CEP7 ratio = 7) with high FGFR2 protein overexpression. Hence, there was intra-patient molecular heterogeneity.

CONCLUSIONS

our findings suggest that concurrent amplification of FGFR2 and MET in GC patients is associated with clinical aggressiveness and may contribute to non-responsiveness to chemotherapy or targeted therapy.

Outcome benefits of bevacizumab biosimilar (SIBP04) combined with carboplatin and paclitaxel in advanced non-squamous non-small-cell lung cancer patients with EGFR mutation: subgroup analysis of a prospective, randomized phase III clinical trial

PURPOSE

SIBP04 is a bevacizumab biosimilar, and bevacizumab combined with carboplatin and paclitaxel in advanced non-squamous non-small-cell lung cancer (nsqNSCLC) has been recommended as the first-line treatment choice. However, the efforts of bevacizumab combined with carboplatin and paclitaxel for nsqNSCLC patients with EGFR mutation remained unclear. Here we report an EGFR mutation subgroup analysis of a prospective, randomized phase III clinical trial (NCT05318443).

METHODS

In this randomized, double-blind, multi-center, parallel controlled, phase III clinical trial, locally advanced, metastatic NSCLC patients were enrolled, and EGFR expression was examined and considered as a stratification factor. All patients received 4 to 6 cycles of paclitaxel and carboplatin plus SIBP04 or bevacizumab 15 mg/kg intravenously followed by SIBP04 15 mg/kg maintenance until intolerable toxicity, disease progression or death. Patients with EGFR mutation and wild-type were assessed for progression-free survival (PFS) and overall survival (OS).

RESULTS

EGFR expression was examined in 398 NSCLC patients (142 with EGFR mutation, 256 with EGFR wild type). PFS in EGFR mutation patients was significantly longer than EGFR wild-type patients (10.91 vs. 7.82 months; HR = 0.692, 95% CI 0.519-0.921, P = 0.011). The median OS in patients with EGFR mutation was not reached while that of EGFR wild-type group was 17.54 months (HR = 0.398, 95% CI 0.275-0.575, P < 0.001). However, there were no significant differences in objective response rate (61.97% vs. 55.86%, P = 0.237) or disease control rate (90.14% vs. 89.84%, P = 0.925).

CONCLUSION

Bevacizumab combined with chemotherapy significantly prolonged the PFS and OS of advanced nsqNSCLC patients with EGFR mutation.

The development of amivantamab for the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) patients with sensitizing oncogenic driver mutations benefit from targeted therapies. Tyrosine kinase inhibitors are highly effective against classic sensitizing epidermal growth factor receptor (EGFR) mutations, such as exon 19 deletions and exon 21 L858R point mutations. Conversely, EGFR exon 20 insertions (exon20ins) are resistant to the traditional EGFR tyrosine kinase inhibitors (TKIs). In May 2021, the US Federal Drug Administration (FDA) provided accelerated approval to amivantamab (Rybrevant) in adults with locally advanced or metastatic NSCLC with EGFR exon20ins after treatment with platinum-based chemotherapy. Amivantamab was the first EGFR/MET bispecific antibody to be approved specifically for EGFR exon20ins where there was an unmet need. Furthermore, amivantamab is being evaluated in additional settings such as post osimertinib in sensitizing EGFR mutations as well as in MET altered NSCLC. Here we discuss amivantamab in regard to its mechanism of action, preclinical and clinical data, and clinical impact for patients with EGFR exon20ins NSCLC and beyond.

HGF/c-Met/β1-integrin signalling axis induces tunneling nanotubes in A549 lung adenocarcinoma cells

Tunneling nanotubes (TNTs) are thin cytoplasmic extensions involved in long-distance intercellular communication and can transport intracellular organelles and signalling molecules. In cancer cells, TNT formation contributes to cell survival, chemoresistance, and malignancy. However, the molecular mechanisms underlying TNT formation are not well defined, especially in different cancers. TNTs are present in non-small cell lung cancer (NSCLC) patients with adenocarcinoma. In NSCLC, hepatocyte growth factor (HGF) and its receptor, c-Met, are mutationally upregulated, causing increased cancer cell growth, survival, and invasion. This study identifies c-Met, β1-integrin, and paxillin as novel components of TNTs in A549 lung adenocarcinoma cells, with paxillin localised at the protrusion site of TNTs. The HGF-induced TNTs in our study demonstrate the ability to transport lipid vesicles and mitochondria. HGF-induced TNT formation is mediated by c-Met and β1-integrin in conjunction with paxillin, followed by downstream activation of MAPK and PI3K pathways and the Arp2/3 complex. These findings demonstrate a potential novel approach to inhibit TNT formation through targeting HGF/c-Met receptor and β1-integrin signalling interactions, which has implications for multi-drug targeting in NSCLC.

The Role of cMET in Gastric Cancer—A Review of the Literature

Gastric cancer (GC) is an important cause of cancer worldwide with over one million new cases yearly. The vast majority of cases present in stage IV disease, and it still bears a poor prognosis. However, since 2010, progress has been made with the introduction of targeted therapies against HER2 and with checkpoint inhibitors (PDL1). More agents interfering with other targets (FGFR2B, CLDN18.2) are being investigated. cMET is a less frequent molecular target that has been studied for gastric cancer. It is a proto-oncogene that leads to activation of the MAPK pathway and the PI3K pathway, which is responsible for activating the MTOR pathway. The prevalence of cMET is strongly debated as different techniques are being used to detect MET-driven tumors. Because of the difference in diagnostic assays, selecting patients who benefit from cMET inhibitors is difficult. In this review, we discuss the pathway of cMET, its clinical significance and the different diagnostic assays that are currently used, such as immunohistochemy (IHC), fluorescence in situ hybridization (FISH), the H-score and next-generation sequencing (NGS). Next, we discuss all the current data on cMET inhibitors in gastric cancer. Since the data on cMET inhibitors are very heterogenous, it is difficult to provide a general consensus on the outcome, as inclusion criteria differ between trials. Diagnosing cMET-driven gastric tumors is difficult, and potentially the only accurate determination of cMET overexpression/amplification may be next-generation sequencing (NGS).

Immunotargeting of Cancer Stem Cells

The generally accepted view is that CSCs hijack the signaling pathways attributed to normal stem cells that regulate the self-renewal and differentiation processes. Therefore, the development of selective targeting strategies for CSC, although clinically meaningful, is associated with significant challenges because CSC and normal stem cells share many important signaling mechanisms for their maintenance and survival. Furthermore, the efficacy of this therapy is opposed by tumor heterogeneity and CSC plasticity. While there have been considerable efforts to target CSC populations by the chemical inhibition of the developmental pathways such as Notch, Hedgehog (Hh), and Wnt/β-catenin, noticeably fewer attempts were focused on the stimulation of the immune response by CSC-specific antigens, including cell-surface targets. Cancer immunotherapies are based on triggering the anti-tumor immune response by specific activation and targeted redirecting of immune cells toward tumor cells. This review is focused on CSC-directed immunotherapeutic approaches such as bispecific antibodies and antibody-drug candidates, CSC-targeted cellular immunotherapies, and immune-based vaccines. We discuss the strategies to improve the safety and efficacy of the different immunotherapeutic approaches and describe the current state of their clinical development.

Picropodophyllotoxin Inhibits Cell Growth and Induces Apoptosis in Gefitinib-Resistant Non-Small Lung Cancer Cells by Dual-Targeting EGFR and MET

Patients with non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) amplification or sensitive mutations initially respond to the tyrosine kinase inhibitor gefitinib, however, the treatment becomes less effective over time by resistance mechanism including mesenchymal-epithelial transition (MET) overexpression. A therapeutic strategy targeting MET and EGFR may be a means to overcoming resistance to gefitinib. In the present study, we found that picropodophyllotoxin (PPT), derived from the roots of Podophyllum hexandrum, inhibited both EGFR and MET in NSCLC cells. The antitumor efficacy of PPT in gefitinib-resistant NSCLC cells (HCC827GR), was confirmed by suppression of cell proliferation and anchorage-independent colony growth. In the targeting of EGFR and MET, PPT bound with EGFR and MET, ex vivo, and blocked both kinases activity. The binding sites between PPT and EGFR or MET in the computational docking model were predicted at Gly772/Met769 and Arg1086/Tyr1230 of each ATP-binding pocket, respectively. PPT treatment of HCC827GR cells increased the number of annexin V-positive and subG1 cells. PPT also caused G2/M cell-cycle arrest together with related protein regulation. The inhibition of EGFR and MET by PPT treatment led to decreases in the phosphorylation of the downstream-proteins, AKT and ERK. In addition, PPT induced reactive oxygen species (ROS) production and GRP78, CHOP, DR5, and DR4 expression, mitochondrial dysfunction, and regulated involving signal-proteins. Taken together, PPT alleviated gefitinib-resistant NSCLC cell growth and induced apoptosis by reducing EGFR and MET activity. Therefore, our results suggest that PPT can be a promising therapeutic agent for gefitinib-resistant NSCLC.

Sorting nexin-dependent therapeutic targeting of oncogenic epidermal growth factor receptor

Overexpression and/or overactivation of the Epidermal Growth Factor Receptor (EGFR) is oncogenic in several tumor types yet targeting the kinase domain of wildtype EGFR has had limited success. EGFR has numerous kinase-independent roles, one of which is accomplished through the Sorting Nexin-dependent retrotranslocation of EGFR to the nucleus, which is observed in some metastatic cancers and therapeutically resistant disease. Here, we have utilized the BAR domain of Sorting Nexin 1 to create a peptide-based therapeutic (cSNX1.3) that promotes cell death in EGFR-expressing cancer. We evaluated the efficacy of cSNX1.3 in tumor-bearing WAP-TGFα transgenic mice (an EGFR-dependent model of breast cancer), where cSNX1.3 treatment resulted in significant tumor regression without observable toxicity. Evaluation of remaining tumor tissues found evidence of increased PARP cleavage, suggesting apoptotic tumor cell death. To evaluate the mechanism of action for cSNX1.3, we found that cSNX1.3 binds the C-terminus of the EGFR kinase domain at an interface site opposite the ATP binding domain with a K_d of ~4.0 µM. In vitro analysis found that cSNX1.3 inhibits the nuclear localization of EGFR. To determine specificity, we evaluated cancer cell lines expressing wildtype EGFR (MDA-MB-468, BT20 and A549), mutant EGFR (H1975) and non-transformed lines (CHO and MCF10A). Only transformed lines expressing wildtype EGFR responded to cSNX1.3, while mutant EGFR and normal cells responded better to an EGFR kinase inhibitor. Phenotypically, cSNX1.3 inhibits EGF-, NRG-, and HGF-dependent migration, but not HA-dependent migration. Together, these data indicate that targeting retrotranslocation of EGFR may be a potent therapeutic for RTK-active cancer.

MET Amplification as a Resistance Driver to TKI Therapies in Lung Cancer: Clinical Challenges and Opportunities

Targeted therapy has emerged as an important pillar for the standard of care in oncogene-driven non-small cell lung cancer (NSCLC), which significantly improved outcomes of patients whose tumors harbor oncogenic driver mutations. However, tumors eventually develop resistance to targeted drugs, and mechanisms of resistance can be diverse. MET amplification has been proven to be a driver of resistance to tyrosine kinase inhibitor (TKI)-treated advanced NSCLC with its activation of EGFR, ALK, RET, and ROS-1 alterations. The combined therapy of MET-TKIs and EGFR-TKIs has shown outstanding clinical efficacy in EGFR-mutated NSCLC with secondary MET amplification-mediated resistance in a series of clinical trials. In this review, we aimed to clarify the underlying mechanisms of MET amplification-mediated resistance to tyrosine kinase inhibitors, discuss the ways and challenges in the detection and diagnosis of MET amplifications in patients with metastatic NSCLC, and summarize the recently published clinical data as well as ongoing trials of new combination strategies to overcome MET amplification-mediated TKI resistance.

Management and Treatment of Non-small Cell Lung Cancer with MET Alteration and Mechanisms of Resistance

OPINION STATEMENT

MET-driven tumors are a heterogenous group of non-small cell lung cancers (NSCLC) with activating mutations. Pathologic activation of MET can be achieved with increased number of gene copies overexpression, or decreased protein degradation through several mechanisms, including mutations, amplifications, or fusions. Besides its role as primary driver, MET activation might also mediate resistance to kinase inhibitors in NSCLC with various other actionable alterations. While checkpoint inhibitors have modest efficacy in MET-driven tumors, several approaches of targeted blockade are available. Among them the most promising are small tyrosine kinase inhibitors, antibody-drug conjugates, and bispecific antibodies. Unfortunately, resistance is virtually inevitable. Resistance to small kinase inhibitors might be mediated by kinase domain mutations or activation of shunting cascades. Various resistance mechanisms might be present in one patient, making it overcoming an unresolved problem.

SH005S7 Overcomes Primary and Acquired Resistance of Non-Small Cell Lung Cancer by Combined MET/EGFR/HER3 Inhibition

In this study, we have examined the anticancer effects of SH005S7 on MET-amplified and (HCC827GR) NSCLC cells and their primary HCC827 cells. In vitro, first of all, cell viability and colony formation assay confirmed the growth inhibitory effects of SH005S7 on both cells. Second, SH005S7 inactivated EGFR-related multiple cell signaling, which was associated with a marked decrease in the constitutive phosphorylation of EGFR, HER3, MET, AKT, and ERK. Third, SH005S7 attenuated the anchorage-independent cell growth. Fourth, SH005S7 blocked invasive and metastatic capability by downregulation of mesenchymal markers—vimentin, snail, and MMP-9. Fifth, BrdU assay confirmed the cell cycle arrest of SH005S7 on these cells. When administered orally to nude mice xenografically transplanted human NSCLC, SH005S7 inhibited the growth of tumor and did not cause hepatotoxicity and nephrotoxicity in animals. Immunohistochemical and Western blot analyses of tissue showed that the suppression of growth correlated with inhibition of proliferation (Ki-67, PCNA), invasiveness (vimentin, snail), and angiogenesis (CD31) marker and decrement in the constitutive and phosphorylation of EGFR, HER3, MET, AKT, and ERK. Additionally, SH005S7 had immune stimulatory effects by TNF-α cytokine release on macrophage, without cell cytotoxicity. Overall, our results suggest that SH005S7 can inhibit the growth of MET-amplified and gefitinib-resistant NSCLC cells through the suppression of EGFR-related multiple targets linked to overcome gefitinib resistance.

[Analysis of the Effcacy and Safety of Amivantamab in Non-small Cell Lung Cancer Patients with EGFR/MET Gene Abnormalities: A Single Center's Experience]

BACKGROUND

Epidermal growth factor receptor (EGFR) and cellular-mesenchymal to epithelial transition factor (c-Met) are widely expressed on cancer cells. There is a synergistic effect of EGFR and HGF/c-Met pathways on proliferation, downstream activation of signal transduction and an additive effect. Studies show that combination of both signaling pathways could potentially be targeted in a synergistic fashion. Amivantamab, a bispecific monoclonal antibody targeting EGFR and c-Met, yielded robust and durable responses in a variety of clinicals trials. However, few researches have reported its efficacy in Chinese non-small cell lung cancer (NSCLC) patients. This study was conducted to evaluate the effectiveness and tolerance of Amivantamab in NSCLC patients with EGFR/MET gene abnormalities at Peking University Cancer Hospital.

METHODS

The study enrolled NSCLC patients who received Amivantamab in our hospital between August 2020 and December 2021, and analyzed the response, survival, and treatment-related adverse events.

RESULTS

Fifteen patients were enrolled in this research, and six of them received Amivantamab treatment and the other nine patients received Amivantamab plus Lazertinib treatment. The rates of partial response (PR), stable disease (SD), and progressive disease (PD) were 46.7% (7/15), 46.7% (7/15) and 6.7% (1/15), respectively. The overall response rate (ORR) and disease control rate (DCR) were 28.6% (2/7) and 100.0% (7/7) in seven patients with EGFR exon 20 insertion, respectively. The ORR and DCR were 40.0% (2/5) and 100.0% (5/5) in five post-osimertinib EGFR-mutant patients, respectively. After a median follow-up of 8.7 months, the median progression-free survival and overall survival were not reached. The most common treatment-related adverse events were rash (86.7%), paronychia (80.0%), and infusion-related reactions (60.0%), and most of them were graded as 1 to 2. Grade 3 to 4 adverse events included rash (33.3%), alanine aminotransferase elevation (13.3%), gamma-glutamyl transpeptidase elevation (13.3%), peripheral edema (6.7%), thromboembolism (6.7%), interstitial lung disease (6.7%), and thrombocytopenia (6.7%).

CONCLUSIONS

Amivantamab was effective in Chinese NSCLC patients with EGFR exon 20 insertion and post-Osimertinib EGFR-mutant patients, similar to the results of clinical trials conducted in western countries. Amivantamab was well tolerated and emphases should be put on adverse events such as rash, paronychia, and infusion-related reactions.

Ring Finger Protein 125 Is an Anti-Proliferative Tumor Suppressor in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide and the only cancer with an increasing incidence in the United States. Recent advances in sequencing technology have enabled detailed profiling of liver cancer genomes and revealed extensive inter- and intra-tumor heterogeneity, making it difficult to identify driver genes for HCC. To identify HCC driver genes, we performed transposon mutagenesis screens in a mouse HBV model of HCC and discovered many candidate cancer genes (SB/HBV-CCGs). Here, we show that one of these genes, RNF125 is a potent anti-proliferative tumor suppressor gene in HCC. RNF125 is one of nine CCGs whose expression was >3-fold downregulated in human HCC. Depletion of RNF125 in immortalized mouse liver cells led to tumor formation in transplanted mice and accelerated growth of human liver cancer cell lines, while its overexpression inhibited their growth, demonstrating the tumor-suppressive function of RNF125 in mouse and human liver. Whole-transcriptome analysis revealed that RNF125 transcriptionally suppresses multiple genes involved in cell proliferation and/or liver regeneration, including Egfr, Met, and Il6r. Blocking Egfr or Met pathway expression inhibited the increased cell proliferation observed in RNF125 knockdown cells. In HCC patients, low expression levels of RNF125 were correlated with poor prognosis demonstrating an important role for RNF125 in HCC. Collectively, our results identify RNF125 as a novel anti-proliferative tumor suppressor in HCC.

Mediating EGFR-TKI Resistance by VEGF/VEGFR Autocrine Pathway in Non-Small Cell Lung Cancer

NSCLC treatment includes targeting of EGFR with tyrosine kinase inhibitors (TKIs) such as Erlotinib; however, resistance to TKIs is commonly acquired through T790M EGFR mutations or overexpression of vascular endothelial growth factor receptor-2 (VEGFR-2). We investigated the mechanisms of EGFR-TKI resistance in NSCLC cell lines with EGFR mutations or acquired resistance to Erlotinib. These studies showed upregulated gene and protein expression of VEGF, VEGFR-2, and a VEGF co-receptor neuropilin-1 (NP-1) in Erlotinib-resistant (1.4-5.3-fold) and EGFR double-mutant (L858R and T790M; 4.1-8.3-fold) NSCLC cells compared to parental and EGFR single-mutant (L858R) NSCLC cell lines, respectively. Immunofluorescence and FACS analysis revealed increased expression of VEGFR-2 and NP-1 in EGFR-TKI-resistant cell lines compared to TKI-sensitive cell lines. Cell proliferation assays showed that treatment with a VEGFR-2 inhibitor combined with Erlotinib lowered cell survival in EGFR double-mutant NSCLC cells to 9% compared to 72% after treatment with Erlotinib alone. Furthermore, Kaplan-Meier analysis revealed shorter median survival in late-stage NSCLC patients with high vs. low VEGFR-2 expression (14 mos vs. 21 mos). The results indicate that VEGFR-2 may play a key role in EGFR-TKI resistance and that combined treatment of Erlotinib with a VEGFR-2 inhibitor may serve as an effective therapy in NSCLC patients with EGFR mutations.

The Emerging Role of c-Met in Carcinogenesis and Clinical Implications as a Possible Therapeutic Target

Background

c-MET is a receptor tyrosine kinase receptor (RTK) for the hepatocyte growth factor (HGF). The binding of HGF to c-MET regulates several cellular functions: differentiation, proliferation, epithelial cell motility, angiogenesis, and epithelial-mesenchymal transition (EMT). Moreover, it is known to be involved in carcinogenesis. Comprehension of HGF-c-MET signaling pathway might have important clinical consequences allowing to predict prognosis, response to treatment, and survival rates based on its expression and dysregulation. Discussion. c-MET represents a useful molecular target for novel engineered drugs. Several clinical trials are underway for various solid tumors and the development of new specific monoclonal antibodies depends on the recent knowledge about the definite c-MET role in each different malignance. Recent clinical trials based on c-MET molecular targets result in good safety profile and represent a promising therapeutic strategy for solid cancers, in monotherapy or in combination with other target drugs.

Conclusion

The list of cell surface receptors crosslinking with the c-MET signaling is constantly growing, highlighting the importance of this pathway for personalized target therapy. Research on the combination of c-MET inhibitors with other drugs will hopefully lead to discovery of new effective treatment options.

KRAS and MET in non-small-cell lung cancer: two of the new kids on the 'drivers' block

Non-small-cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced to identify various critical oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalized treatment based on the tumor's molecular genomics. This review presents a comprehensive review of the biology, new therapeutic interventions, and resistance patterns of two well-defined subgroups, tumors with KRAS and MET alterations. We also discuss the status of molecular testing practices for these two key oncogenic drivers, considering the progressive introduction of next-generation sequencing (NGS) and RNA sequencing in regular clinical practice.

Therapeutic exploration of uncommon EGFR exon 20 insertion mutations in advanced non-small cell lung cancer: breaking through brambles and thorns

BACKGROUND

EGFR exon 20 insertion (EGFR ex20ins) mutations account for about 10-12% of all EGFR-mutated tumors, which are usually associated with primary drug resistance to conventional EGFR-TKI therapy and worse survival outcomes, and are currently a major problem for clinicians in clinical management. In recent years, with the rapid improvement of sequencing technology and careful review of clinical data, investigators have gained a deeper understanding and clearer cognition of the clinicopathological features and molecular mechanisms of these EGFR ex20ins mutations.

PURPOSE

The aim of this study was to systemically review the molecular structure and clinical characteristics of EGFR ex20ins mutations, and focus on summarizing the latest data of emerging therapies (including novel small-molecule EGFR-TKI drugs, specific monoclonal antibodies, novel drugs targeting other mechanisms, and immunotherapy) for those patients.

CONCLUSION

Advances in overcoming these systemic challenges have greatly accelerated the development of new drugs targeting EGFR ex20ins, and are committed to designing more rational combination therapies to overcome or delay the emergence of drug resistance, ultimately improve the prognosis of such uncommon mutant populations.

Novel Pyridine Bioisostere of Cabozantinib as a Potent c-Met Kinase Inhibitor: Synthesis and Anti-Tumor Activity against Hepatocellular Carcinoma

Two novel bioisosteres of cabozantinib, 3 and 4, were designed and synthesized. The benzene ring in the center of the cabozantinib structure was replaced by trimethylpyridine (3) and pyridine (4), respectively. Surprisingly, the two compounds showed extremely contrasting mesenchymal-epithelial transition factor (c-Met) inhibitory activities at 1 μM concentration (4% inhibition of 3 vs. 94% inhibition of 4). The IC₅₀ value of compound 4 was 4.9 nM, similar to that of cabozantinib (5.4 nM). A ligand-based docking study suggested that 4 includes the preferred conformation for the binding to c-Met in the conformational ensemble, but 3 does not. The anti-proliferative activity of compound 4 against hepatocellular carcinoma (Hep3B and Huh7) and non-small-cell lung cancer (A549 and H1299) cell lines was better than that of cabozantinib, whereas 3 did not show a significant anti-proliferative activity. Moreover, the tumor selectivity of compound 4 toward hepatocellular carcinoma cell lines was higher than that of cabozantinib. In the xenograft chick tumor model, compound 4 inhibited Hep3B tumor growth to a much greater extent than cabozantinib. The present study suggests that compound 4 may be a good therapeutic candidate against hepatocellular carcinoma.

Dual targeting of MEK and PI3K effectively controls the proliferation of human EGFR-TKI resistant non-small cell lung carcinoma cell lines with different genetic backgrounds

Background

Molecular targeted therapy for non-small cell lung carcinoma (NSCLC) is restricted due to resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). This study evaluated the effects of dual targeting of MEK and PI3K in human EGFR-TKI resistant NSCLC cell lines.

Methods

EGFR-TKI resistant NSCLC cell lines H1975, H460, and A549, with different mutation and amplification status in EGFR, K-RAS, PIK3CA, and MET genes, were treated with a MEK162 (MEK inhibitor) and BKM120 (PI3K inhibitor) combination or a BIBW2992 (EGFR inhibitor) and ARQ197 (MET inhibitor) combination and assayed for cell proliferation, apoptosis, and cell cycle distribution.

Results

Dual targeting of MEK and PI3K efficiently inhibited the cell proliferation, induced apoptosis and the G0/G1 cell cycle, and decreased the phosphorylation of ERK1/2, AKT, S6, and 4E-BP1. H460 cells with K-RAS and PIK3CA mutation were most sensitive to MEK162 and BKM120 combinations. H1975 cells with EGFR and PIK3CA mutation and MET amplification were sensitive to BIBW2992 and ARQ197 combinations.

Conclusion

Dual targeting regulated the proliferation of EGFR-TKI-resistant NSCLC cells, especially mutants in K-RAS and PIK3CA that are promising for EGFR-TKI-resistant NSCLC therapeutics.

MET alterations and their impact on the future of non-small cell lung cancer (NSCLC) targeted therapies

Introduction: The MET gene and its pathway normally plays a crucial role in cell homeostasis, motility, and apoptosis. However, when the MET gene is altered, there is an imbalance toward cell proliferation and invasion commonly seen in numerous different types of cancers. The heterogeneous group of MET alterations that includes MET amplification, MET exon 14 skipping mutation, and MET fusions has been difficult to diagnose and treat. Currently, treatments are focused on tyrosine kinase inhibitors but now there is emerging data on novel MET-targeted therapies including monoclonal antibodies and antibody-drug conjugates that have emerged.Areas covered: We introduce new emerging data on MET alterations in non-small cell lung cancer (NSCLC) that has contributed to advances in MET targeted therapeutics. We offer our perspective and examine new information on the mechanisms of the MET alterations in this review.Expert opinion: Given the trends currently involving the targeting of MET altered malignancies, there will most likely be a continued rapid expansion of testing, novel tyrosine kinase inhibitors and potent antibody approaches. Combination treatments will be necessary to optimize management of advanced and early disease.

Discovery of amivantamab (JNJ-61186372), a bispecific antibody targeting EGFR and MET

A bispecific antibody (BsAb) targeting the epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor (MET) pathways represents a novel approach to overcome resistance to targeted therapies in patients with non-small cell lung cancer. In this study, we sequentially screened a panel of BsAbs in a combinatorial approach to select the optimal bispecific molecule. The BsAbs were derived from different EGFR and MET parental monoclonal antibodies. Initially, molecules were screened for EGFR and MET binding on tumor cell lines and lack of agonistic activity toward MET. Hits were identified and further screened based on their potential to induce untoward cell proliferation and cross-phosphorylation of EGFR by MET via receptor colocalization in the absence of ligand. After the final step, we selected the EGFR and MET arms for the lead BsAb and added low fucose Fc engineering to generate amivantamab (JNJ-61186372). The crystal structure of the anti-MET Fab of amivantamab bound to MET was solved, and the interaction between the two molecules in atomic details was elucidated. Amivantamab antagonized the hepatocyte growth factor (HGF)-induced signaling by binding to MET Sema domain and thereby blocking HGF β-chain-Sema engagement. The amivantamab EGFR epitope was mapped to EGFR domain III and residues K443, K465, I467, and S468. Furthermore, amivantamab showed superior antitumor activity over small molecule EGFR and MET inhibitors in the HCC827-HGF in vivo model. Based on its unique mode of action, amivantamab may provide benefit to patients with malignancies associated with aberrant EGFR and MET signaling.

Combination of HGF/MET-targeting agents and other therapeutic strategies in cancer

MET receptor has emerged as a druggable target across several human cancers. Agents targeting MET and its ligand hepatocyte growth factor (HGF) including small molecules such as crizotinib, tivantinib and cabozantinib or antibodies including rilotumumab and onartuzumab have proven their values in different tumors. Recently, capmatinib was approved for treatment of metastatic lung cancer with MET exon 14 skipping. In this review, we critically examine the current evidence on how HGF/MET combination therapies may take advantage of synergistic effects, overcome primary or acquired drug resistance, target tumor microenvironment, modulate drug metabolism or tackle pharmacokinetic issues. Preclinical and clinical studies on the combination of HGF/MET-targeted agents with conventional chemotherapeutics or molecularly targeted treatments (including EGFR, VEGFR, HER2, RAF/MEK, and PI3K/Akt targeting agents) and also the value of biomarkers are examined. Our deeper understanding of molecular mechanisms underlying successful pharmacological combinations is crucial to find the best personalized treatment regimens for cancer patients.

Novel Therapies for Metastatic Non-Small Cell Lung Cancer with MET Exon 14 Alterations: A Spotlight on Capmatinib

MET exon 14 (METex14) alterations are now an established therapeutically tractable target in non-small cell lung cancer (NSCLC). Recently reported trials of several MET tyrosine kinase inhibitors (TKI) in this patient population have demonstrated promising efficacy data in both the treatment naïve and pre-treated settings and have led to regulatory approvals. This review will focus on practical diagnostic considerations for METex14 alterations, the trial evidence for capmatinib in this molecular subset including dosing and toxicity management, and the future therapeutic landscape of METex14 altered NSCLC.

Resistance to Molecularly Targeted Therapies in Melanoma

Malignant melanoma is the most aggressive type of skin cancer with invasive growth patterns. In 2021, 106,110 patients are projected to be diagnosed with melanoma, out of which 7180 are expected to die. Traditional methods like surgery, radiation therapy, and chemotherapy are not effective in the treatment of metastatic and advanced melanoma. Recent approaches to treat melanoma have focused on biomarkers that play significant roles in cell growth, proliferation, migration, and survival. Several FDA-approved molecular targeted therapies such as tyrosine kinase inhibitors (TKIs) have been developed against genetic biomarkers whose overexpression is implicated in tumorigenesis. The use of targeted therapies as an alternative or supplement to immunotherapy has revolutionized the management of metastatic melanoma. Although this treatment strategy is more efficacious and less toxic in comparison to traditional therapies, targeted therapies are less effective after prolonged treatment due to acquired resistance caused by mutations and activation of alternative mechanisms in melanoma tumors. Recent studies focus on understanding the mechanisms of acquired resistance to these current therapies. Further research is needed for the development of better approaches to improve prognosis in melanoma patients. In this article, various melanoma biomarkers including BRAF, MEK, RAS, c-KIT, VEGFR, c-MET and PI3K are described, and their potential mechanisms for drug resistance are discussed.

Exposure to chewing tobacco promotes primary oral squamous cell carcinoma and regional lymph node metastasis by alterations of SDF1α/CXCR4 axis

A high incidence of oral squamous cell carcinoma (OSCC) is observed in South-East Asian countries due to addictions such as chewing tobacco. Local invasion and distant metastases are primary causes of poor prognosis in OSCC. This study aimed to understand the alterations in metastasis biomarkers, such as stromal cell-derived factor-1α (SDF-1 or SDF1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4), in OSCC patient samples that were stratified based on the history of addiction to chewing tobacco. Targeted immunohistochemical staining and Western blotting were performed on primary tumour and metastatic lymph node (LN) tissues in parallel. Overexpression of hepatocyte growth factor (HGF), activated form of its cognate receptor tyrosine kinase, c-Met (p-Met), GRB2-associated-binding protein 1 (Gab1), phospho-protein kinase B (pAkt), nuclear factor kappa B (NF-κB) and cyclooxygenase-2 (COX-2) were observed in primary tumour and metastatic lymph nodes in both chewer and non-chewer cohorts. Variance analysis showed significant positive correlation between them (P < .0001) indicating upregulation of these biomarkers upon ligand-induced activation of c-Met in both tobacco chewers and non-chewers. Significantly higher expressions of SDF1α and CXCR4 were observed in both primary tumours and metastatic lymph nodes of tobacco chewers (P < .0001) and coincided with overexpressed HGF. In contrast, no significant correlation was observed between expression of HGF and that of SDF1α and CXCR4 in non-chewers. Together, our findings provide important insights into the association of HGF/c-Met and the SDF1α/CXCR4 axis in lymph node metastasis and to an aetiological link with the habit of chewing tobacco.

Development of [89Zr]ZrDFO-amivantamab bispecific to EGFR and c-MET for PET imaging of triple-negative breast cancer

BACKGROUND

Amivantamab is a novel bispecific antibody that simultaneously targets the epidermal growth factor receptor (EGFR) and the hepatocyte growth factor receptor (HGFR/c-MET) that are overexpressed in several types of cancer including triple-negative breast cancer (TNBC). Targeting both receptors simultaneously can overcome resistance to mono-targeted therapy. The purpose of this study is to develop 89Zr-labeled amivantamab as a potential companion diagnostic imaging agent to amivantamab therapy using various preclinical models of TNBC for evaluation.

METHODS

Amivantamab was conjugated to desferrioxamine (DFO) and radiolabeled with 89Zr to obtain [89Zr]ZrDFO-amivantamab. Binding of the bispecific [89Zr]ZrDFO-amivantamab as well as its mono-specific "single-arm" antibody controls were determined in vitro and in vivo. Biodistribution studies of [89Zr]ZrDFO-amivantamab were performed in MDA-MB-468 xenografts to determine the optimal imaging time point. PET/CT imaging with [89Zr]ZrDFO-amivantamab or its isotype control was performed in a panel of TNBC xenografts with varying levels of EGFR and c-MET expression.

RESULTS

[89Zr]ZrDFO-amivantamab was synthesized with a specific activity of 148 MBq/mg and radiochemical yield of ≥ 95%. Radioligand binding studies and western blot confirmed the order of EGFR and c-MET expression levels: HCC827 lung cancer cell (positive control) > MDA-MB-468 > MDA-MB-231 > MDA-MB-453. [89Zr]ZrDFO-amivantamab demonstrated bispecific binding in cell lines co-expressed with EGFR and c-MET. PET/CT imaging with [89Zr]ZrDFO-amivantamab in TNBC xenografted mice showed standard uptake value (SUVmean) of 6.0 ± 1.1 in MDA-MB-468, 4.2 ± 1.4 in MDA-MB-231, and 1.5 ± 1.4 in MDA-MB-453 tumors, which are consistent with their receptors' expression levels on the cell surface.

CONCLUSION

We have successfully prepared a radiolabeled bispecific antibody, [89Zr]ZrDFO-amivantamab, and evaluated its pharmacologic and imaging properties in comparison with its single-arm antibodies and non-specific isotype controls. [89Zr]ZrDFO-amivantamab demonstrated the greatest uptake in tumors co-expressing EGFR and c-MET.

Targeting cancer metastasis with antibody therapeutics

Cancer metastasis, the spread of disease from a primary to a distal site through the circulatory or lymphatic systems, accounts for over 90% of all cancer related deaths. Despite significant progress in the field of cancer therapy in recent years, mortality rates remain dramatically higher for patients with metastatic disease versus those with local or regional disease. Although there is clearly an urgent need to develop drugs that inhibit cancer spread, the overwhelming majority of anticancer therapies that have been developed to date are designed to inhibit tumor growth but fail to address the key stages of the metastatic process: invasion, intravasation, circulation, extravasation, and colonization. There is growing interest in engineering targeted therapeutics, such as antibody drugs, that inhibit various steps in the metastatic cascade. We present an overview of antibody therapeutic approaches, both in the pipeline and in the clinic, that disrupt the essential mechanisms that underlie cancer metastasis. These therapies include classes of antibodies that indirectly target metastasis, including anti-integrin, anticadherin, and immune checkpoint blocking antibodies, as well as monoclonal and bispecific antibodies that are specifically designed to interrupt disease dissemination. Although few antimetastatic antibodies have achieved clinical success to date, there are many promising candidates in various stages of development, and novel targets and approaches are constantly emerging. Collectively, these efforts will enrich our understanding of the molecular drivers of metastasis, and the new strategies that arise promise to have a profound impact on the future of cancer therapeutic development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Targeted inhibition of c-MET by podophyllotoxin promotes caspase-dependent apoptosis and suppresses cell growth in gefitinib-resistant non-small cell lung cancer cells

BACKGROUND

Lung cancer has the highest incidence and cancer-related mortality of all cancers worldwide. Its treatment is focused on molecular targeted therapy. c-MET plays an important role in the development and metastasis of various human cancers and has been identified as an attractive potential anti-cancer target. Podophyllotoxin (PPT), an aryltetralin lignan isolated from the rhizomes of Podophyllum species, has several pharmacological activities that include anti-viral and anti-cancer effects. However, the mechanism of the anti-cancer effects of PPT on gefitinib-sensitive (HCC827) or -resistant (MET-amplified HCC827GR) non-small cell lung cancer (NSCLC) cells remains unexplored.

PURPOSE

In the present study, we investigated the underlying mechanisms of PPT-induced apoptosis in NSCLC cells and found that the inhibition of c-MET kinase activity contributed to PPT-induced cell death.

METHODS

The regulation of c-MET by PPT was examined by pull-down assay, ATP-competitive binding assay, kinase activity assay, molecular docking simulation, and Western blot analysis. The cell growth inhibitory effects of PPT on NSCLC cells were assessed using the MTT assay, soft agar assay, and flow cytometry analysis.

RESULTS

PPT could directly interact with c-MET and inhibit kinase activity, which further induced the apoptosis of HCC827GR cells. In contrast, PPT did not significantly affect EGFR kinase activity. PPT significantly inhibited the cell viability of HCC827GR cells, whereas the PPT-treated HCC827 cells showed a cell viability of more than 80%. PPT dose-dependently induced G2/M cell cycle arrest, as shown by the downregulation of cyclin B1 and cdc2, and upregulation of p27 expression in HCC827GR cells. Furthermore, PPT treatment induced Bad expression and downregulation of Mcl-1, survivin, and Bcl-xl expression, subsequently activating multi-caspases. PPT thereby induced caspase-dependent apoptosis in HCC827GR cells.

CONCLUSION

These results suggest the potential of PPT as a c-MET inhibitor to overcome tyrosine kinase inhibitor resistance in lung cancer.

Inhibiting insulin and mTOR signaling by afatinib and crizotinib combination fosters broad cytotoxic effects in cutaneous malignant melanoma

Current treatment modalities for disseminated cutaneous malignant melanoma (CMM) improve survival, however disease progression commonly ensues. In a previous study we identified afatinib and crizotinib in combination as a novel potential therapy for CMM independent of BRAF/NRAS mutation status. Herein, we elucidate the underlying mechanisms of the combination treatment effect to find biomarkers and novel targets for development of therapy that may provide clinical benefit by proteomic analysis of CMM cell lines and xenografts using mass spectrometry based analysis and reverse phase protein array. Identified candidates were validated using immunoblotting or immunofluorescence. Our analysis revealed that mTOR/Insulin signaling pathways were significantly decreased by the afatinib and crizotinib combination treatment. Both in vitro and in vivo analyses showed that the combination treatment downregulated pRPS6KB1 and pRPS6, downstream of mTOR signaling, and IRS-1 in the insulin signaling pathway, specifically ablating IRS-1 nuclear signal. Silencing of RPS6 and IRS-1 alone had a similar effect on cell death, which was further induced when IRS-1 and RPS6 were concomitantly silenced in the CMM cell lines. Silencing of IRS-1 and RPS6 resulted in reduced sensitivity towards combination treatment. Additionally, we found that IRS-1 and RPS6KB1 expression levels were increased in advanced stages of CMM clinical samples. We could demonstrate that induced resistance towards combination treatment was reversible by a drug holiday. CD171/L1CAM, mTOR and PI3K-p85 were induced in the combination resistant cells whereas AXL and EPHA2, previously identified mediators of resistance to MAPK inhibitor therapy in CMM were downregulated. We also found that CD171/L1CAM and mTOR were increased at progression in tumor biopsies from two matched cases of patients receiving targeted therapy with BRAFi. Overall, these findings provide insights into the molecular mechanisms behind the afatinib and crizotinib combination treatment effect and leverages a platform for discovering novel biomarkers and therapy regimes for CMM treatment.

CRISPR-Cas12a with an oAd Induces Precise and Cancer-Specific Genomic Reprogramming of EGFR and Efficient Tumor Regression

CRISPR-Cas12a represents a class 2/type V CRISPR RNA-guided endonuclease, holding promise as a precise genome-editing tool in vitro and in vivo. For efficient delivery of the CRISPR-Cas system into cancer, oncolytic adenovirus (oAd) has been recognized as a promising alternative vehicle to conventional cancer therapy, owing to its cancer specificity; however, to our knowledge, it has not been used for genome editing. In this study, we show that CRISPR-Cas12a mediated by oAd disrupts the oncogenic signaling pathway with excellent cancer specificity. The intratumoral delivery of a single oAd co-expressing a Cas12a and a CRISPR RNA (crRNA) targeting the epidermal growth factor receptor (EGFR) gene (oAd/Cas12a/crEGFR) induces efficient and precise editing of the targeted EGFR gene in a cancer-specific manner, without detectable off-target nuclease activity. Importantly, oAd/Cas12a/crEGFR elicits a potent antitumor effect via robust induction of apoptosis and inhibition of tumor cell proliferation, ultimately leading to complete tumor regression in a subset of treated mice. Collectively, in this study we show precise genomic reprogramming via a single oAd vector-mediated CRISPR-Cas system and the feasibility of such system as an alternative cancer therapy.

Blocking c-MET/ERBB1 Axis Prevents Brain Metastasis in ERBB2+ Breast Cancer

Simple Summary

Targeted monotherapies are ineffective in the treatment of brain metastasis of ERBB2⁺ breast cancer (BC) underscoring the need for combination therapies. The lack of robust preclinical models has further hampered the assessment of treatment modalities. We report here a clinically relevant orthotopic mouse model of ERBB2⁺ BC that spontaneously metastasizes to brain and demonstrates that targeting the c-MET/ERBB1 axis with a combination of cabozantinib and neratinib decreases primary tumor growth and prevents brain metastasis in ERBB2⁺ BC.

Abstract

Brain metastasis (BrM) remains a significant cause of cancer-related mortality in epidermal growth factor receptor 2-positive (ERBB2⁺) breast cancer (BC) patients. We proposed here that a combination treatment of irreversible tyrosine kinase inhibitor neratinib (NER) and the c-MET inhibitor cabozantinib (CBZ) could prevent brain metastasis. To address this, we first tested the combination treatment of NER and CBZ in the brain-seeking ERBB2⁺ cell lines SKBrM3 and JIMT-1-BR3, and in ERBB2⁺ organoids that expressed the c-MET/ERBB1 axis. Next, we developed and characterized an orthotopic mouse model of spontaneous BrM and evaluated the therapeutic effect of CBZ and NER in vivo. The combination treatment of NER and CBZ significantly inhibited proliferation and migration in ERBB2⁺ cell lines and reduced the organoid growth in vitro. Mechanistically, the combination treatment of NER and CBZ substantially inhibited ERK activation downstream of the c-MET/ERBB1 axis. Orthotopically implanted SKBrM3⁺ cells formed primary tumor in the mammary fat pad and spontaneously metastasized to the brain and other distant organs. Combination treatment with NER and CBZ inhibited primary tumor growth and predominantly prevented BrM. In conclusion, the orthotopic model of spontaneous BrM is clinically relevant, and the combination therapy of NER and CBZ might be a useful approach to prevent BrM in BC.

EGFR/c-Met and mTOR signaling are predictors of survival in non-small cell lung cancer

BACKGROUND

EGFR/c-Met activation/amplification and co-expression, mTOR upregulation/activation, and Akt/Wnt signaling upregulation have been individually associated with more aggressive disease and characterized as potential prognostic markers for lung cancer patients.

METHODS

Tumors obtained from 109 participants with stage I-IV non-small cell lung cancer (NSCLC) were studied for EGFR/c-Met co-localization as well as for total and active forms of EGFR, c-Met, mTOR, S6K, beta-catenin, and Axin2. Slides were graded by two independent blinded pathologists using a validated scoring system. Protein expression profile correlations were assessed using Pearson correlation and Spearman's rho. Prognosis was assessed using Kaplan-Meier analysis.

RESULTS

Protein expression profile analysis revealed significant correlations between EGFR/p-EGFR (p = 0.0412) and p-mTOR/S6K (p = 0.0044). Co-localization of p-EGFR/p-c-Met was associated with increased p-mTOR (p = 0.0006), S6K (p = 0.0018), and p-S6K (p < 0.0001) expression. In contrast, active beta-catenin was not positively correlated with EGFR/c-Met nor any activated proteins. Axin2, a negative regulator of the Wnt pathway, was correlated with EGFR, p-EGFR, p-mTOR, p-S6K, EGFR/c-Met co-localization, and p-EGFR/p-c-Met co-localization (all p-values <0.03). Kaplan-Meier analysis revealed shorter median survival in participants with high expression of Axin2, total beta-catenin, total/p-S6K, total/p-mTOR, EGFR, and EGFR/c-Met co-localization compared with low expression. After controlling for stage of disease at diagnosis, subjects with late-stage disease demonstrated shorter median survival when exhibiting high co-expression of EGFR/c-Met (8.1 month versus 22.3 month, p = 0.050), mTOR (6.7 month versus 22.3 month, p = 0.002), and p-mTOR (8.1 month versus 25.4 month, p = 0.004) compared with low levels.

CONCLUSIONS

These findings suggest that increased EGFR/c-Met signaling is correlated with upregulated mTOR/S6K signaling, which may in turn be associated with shorter median survival in late-stage NSCLC.

Emerging role of phytochemicals in targeting predictive, prognostic, and diagnostic biomarkers of lung cancer

Lung-cancer is the foremost cause of cancer in humans worldwide, of which 80-85% cases are composed of non-small cell lung carcinoma. All treatment decisions depend on the pattern of biomarkers selection to enhance the response to the targeted therapies. Although advanced treatments are available for lung-cancer, the disease treatment remains not adequate. There are several synthetic chemotherapeutic agents available for the treatment of lung cancer. However, due to their toxic effect, survival rate is still 15-18%. Besides, medicinal plants are a huge reservoir of natural products that provide protective effects against lung cancer. Likewise, successful studies of potential phytochemicals in targeting lung-cancer biomarkers have created a novel paradigm for the discovery of potent drugs against lung-cancer. Hence, to defeat severe toxicity and resistance towards the synthetic drugs, detailed studies are required regarding the available phytochemicals and targets responsible for the treatment of lung-cancer. The present review provides a comprehensive information about the lung-cancer biomarkers under the classification of predictive, prognostic, and diagnostic type. Moreover, it discusses and enlists the phytochemicals with mode of action against different biomarkers, effective doses in in vitro, in vivo, and clinical studies, the limitations associated with usage of phytochemicals as a drug to prevent/cure lung-cancer and the latest techniques employed to overcome such issues.

Synthesis and biological evaluation of quinoxaline derivatives as specific c-Met kinase inhibitors

A series of novel quinoxaline derivatives were synthesized and evaluated for their inhibitory activity against c-Met kinase enzyme. Most of the tested compounds exhibited potent inhibitory activity. All the synthesized quinoxaline compounds were further examined against c-Met overexpressed human gastric cancer cell line (MKN-45), which showed good inhibitory activity. Among the synthesized compounds, compound 4 exhibited better tumor growth inhibition in the animal model study; we also confirmed its acceptable drug property and highly selective target activity.

MET receptor in oncology: From biomarker to therapeutic target

First discovered in the 1984, the MET receptor tyrosine kinase (RTK) and its ligand hepatocyte growth factor or HGF (also known as scatter factor or SF) are implicated as key players in tumor cell migration, proliferation, and invasion in a variety of cancers. This pathway also plays a key role during embryogenesis in the development of muscular and nervous structures. High expression of the MET receptor has been shown to correlate with poor prognosis and resistance to therapy. MET exon 14 splicing variants, initially identified by us in lung cancer, is actionable through various tyrosine kinase inhibitors (TKIs). For this reason, this pathway is of interest as a therapeutic target. In this chapter we will be discussing the history of MET, the genetics of this RTK, and give some background on the receptor biology. Furthermore, we will discuss directed therapeutics, mechanisms of resistance, and the future of MET as a therapeutic target.

Advances in targeting acquired resistance mechanisms to epidermal growth factor receptor tyrosine kinase inhibitors

Next-generation sequencing (NGS) of tumor samples and circulating tumor DNA has revolutionized diagnostic and therapeutic strategies in lung cancer. The identification of the epidermal growth factor receptor (EGFR) oncogenic driver has translated into successful therapy of advanced lung cancer using EGFR tyrosine kinase inhibitors (TKI). Unfortunately, responses are limited by acquired mechanisms of resistance. We review herein the current landscape of acquired resistance mechanisms to EGFR-TKI therapy and recent advances in therapeutic strategies to overcome acquired resistance.

MET Oncogene in Non-Small Cell Lung Cancer: Mechanism of MET Dysregulation and Agents Targeting the HGF/c-Met Axis

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide and has a poor prognosis. Current treatments for advanced NSCLC included traditional chemotherapy, radiotherapy, targeted therapy, and immunotherapy. The efficacy of targeted therapy relies on oncogene addiction. Mesenchymal-epithelial transition factor (MET) gene can encode unconventional receptor tyrosine kinases with pleiotropic functions, when signals are abnormally activated, it can initiate and maintain tumor transformation, promote cell proliferation, survival, tumor invasion and angiogenesis. Thus, it is a promising therapeutic target. Previous studies have shown that elevated levels of HGF and/or overexpression of c-Met are associated with poor prognosis in lung cancer. In preclinical and clinical trials, c-MET inhibitors have shown some antitumor activity in NSCLC. Although the efficacy results of MET inhibitors in Phase III clinical trials are disappointing, given the molecular heterogeneity of NSCLC, only subgroups of patients with MET gene alterations may benefit from c-MET inhibitors. The challenge for the future is to screen out the potential beneficiaries. To solve this problem, there is need for large data analysis for the detection methods and treatment effects, to establish standards that meet the MET activation status, and determine reliable thresholds to achieve effective patient stratification and clinical decision making. This article summarized the structure of the hepatocyte growth factor (HGF)/c-Met axis, the different mechanisms of MET addiction, as well as MET amplification as acquired resistance mechanism to epidermal growth factor receptor-tyrosine kinase inhibitors, the latest advances of MET inhibitors, and immuotherapy in the treatment of NSCLC with MET alterations.

Licochalcone D Induces ROS-Dependent Apoptosis in Gefitinib-Sensitive or Resistant Lung Cancer Cells by Targeting EGFR and MET

Licochalcone D (LCD), a flavonoid isolated from a Chinese medicinal plant Glycyrrhiza inflata, has a variety of pharmacological activities. However, the anti-cancer effects of LCD on non-small cell lung cancer (NSCLC) have not been investigated yet. The amplification of MET (hepatocyte growth factor receptor) compensates for the inhibition of epidermal growth factor receptor (EGFR) activity due to tyrosine kinase inhibitor (TKI), leading to TKI resistance. Therefore, EGFR and MET can be attractive targets for lung cancer. We investigated the anti-proliferative and apoptotic effects of LCD in lung cancer cells HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, pull-down/kinase assay, cell cycle analysis, Annexin-V/7-ADD staining, reactive oxygen species (ROS) assay, mitochondrial membrane potential (MMP) assay, multi-caspase assay, and Western blot analysis. The results showed that LCD inhibited phosphorylation and the kinase activity of EGFR and MET. In addition, the predicted pose of LCD was competitively located at the ATP binding site. LCD suppressed lung cancer cells growth by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LCD also induced caspases activation and poly (ADP-ribose) polymerase (PARP) cleavage, thus displaying features of apoptotic signals. These results provide evidence that LCD has anti-tumor effects by inhibiting EGFR and MET activities and inducing ROS-dependent apoptosis in NSCLC, suggesting that LCD has the potential to treat lung cancer.

Connecting Cancer Pathways to Tumor Engines: A Stratification Tool for Colorectal Cancer Combining Human In Vitro Tissue Models with Boolean In Silico Models

To improve and focus preclinical testing, we combine tumor models based on a decellularized tissue matrix with bioinformatics to stratify tumors according to stage-specific mutations that are linked to central cancer pathways. We generated tissue models with BRAF-mutant colorectal cancer (CRC) cells (HROC24 and HROC87) and compared treatment responses to two-dimensional (2D) cultures and xenografts. As the BRAF inhibitor vemurafenib is-in contrast to melanoma-not effective in CRC, we combined it with the EGFR inhibitor gefitinib. In general, our 3D models showed higher chemoresistance and in contrast to 2D a more active HGFR after gefitinib and combination-therapy. In xenograft models murine HGF could not activate the human HGFR, stressing the importance of the human microenvironment. In order to stratify patient groups for targeted treatment options in CRC, an in silico topology with different stages including mutations and changes in common signaling pathways was developed. We applied the established topology for in silico simulations to predict new therapeutic options for BRAF-mutated CRC patients in advanced stages. Our in silico tool connects genome information with a deeper understanding of tumor engines in clinically relevant signaling networks which goes beyond the consideration of single drivers to improve CRC patient stratification.

Design and Evaluation of PEGylated Liposomal Formulation of a Novel Multikinase Inhibitor for Enhanced Chemosensitivity and Inhibition of Metastatic Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has one of the highest mortality rates among cancers. Chemotherapy is the standard first-line treatment, but only modest survival benefits are observed. With the advent of targeted therapies, epidermal growth factor receptor (EGFR) has been acknowledged as a prospective target in PDAC since it is overexpressed in up to 60% of cases. Similarly, the tyrosine-protein kinase Met (cMET) is also overexpressed in PDAC (27-60%) and is a prognostic marker for poor survival. Interestingly, EGFR and cMET share some common signaling pathways including PI3K/Akt and MAPK pathways. Small molecule inhibitors or bispecific antibodies that can target both EGFR and cMET are therefore emerging as novel options for cancer therapy. We previously developed a dual EGFR and cMET inhibitor (N19) that was able to inhibit tumor growth in nonsmall cell lung cancer models resistant to EGFR tyrosine kinase inhibitors (TKI). Here, we report the development of a novel liposomal formulation of N19 (LN19) and showed significant growth inhibition and increased sensitivity toward gemcitabine in the pancreatic adenocarcinoma orthotopic xenograft model. Taken together, our results suggest that LN19 can be valued as an effective combination therapy with conventional chemotherapy such as gemcitabine for PDAC patients.

Licochalcone B inhibits growth and induces apoptosis of human non-small-cell lung cancer cells by dual targeting of EGFR and MET

BACKGROUND

Epidermal growth factor receptor (EGFR) gene alterations are associated with sensitization to tyrosine kinase inhibitors such as gefitinib in lung cancer. Some patients suffering from non-small cell lung cancer (NSCLC) have difficulty in treating the cancer due to resistance acquired to gefitinib with MET amplification. Therefore EGFR and MET may be attractive targets for lung cancer therapy.

PURPOSE

This study aimed to investigate the anti-cancer activity of Licochalcone (LC)B extracted from Glycyrrhiza inflata, in gefitinib-sensitive or gefitinib-resistant NSCLC cells, and to define its mechanisms.

STUDY DESIGN

We investigated the mechanism of action of LCB by targeting EGFR and MET in human NSCLC cells.

METHODS

We used the HCC827 and HCC827GR lines as gefitinib-sensitive and -resistant cells respectively, and determined the effects of LCB on both, by performing cell proliferation assay, flow cytometry analysis and Western blotting. Targets of LCB were identified by pull-down/kinase assay and molecular docking simulation.

RESULTS

LCB inhibited both EGFR and MET kinase activity by directly binding to their ATP-binding pockets. The ability of this interaction was verified by computational docking and molecular dynamics simulations. LCB suppressed viability and colony formation of both HCC827 and HCC827GR cells while exhibiting no cytotoxicity to normal cells. The induction of G2/M cell-cycle arrest and apoptosis by LCB was confirmed by Annexin V/7-AAD double staining, ER stress and reactive oxygen species induction, mitochondrial membrane potential loss and caspase activation as well as related-proteins regulation. Inhibition of EGFR and MET by LCB decreased ERBB3 and AKT axis activation.

CONCLUSION

We provide insights into the LCB-mediated mechanisms involved in reducing cell proliferation and inducing apoptosis in NSCLC cells. This occurs through dual inhibition of EGFR and MET in NSCLC cells regardless of their sensitivity or resistance to gefitinib. LCB may be a promising novel therapeutic medicine for gefitinib-sensitive or resistant NSCLC treatment.

Combining ERBB family and MET inhibitors is an effective therapeutic strategy in cutaneous malignant melanoma independent of BRAF/NRAS mutation status

Current treatment modalities for disseminated cutaneous malignant melanoma (CMM) improve survival; however, relapses are common. A number of receptor tyrosine kinases (RTKs) including EGFR and MET have been reported to be involved in CMM metastasis and in the development of resistance to therapy, targeting the mitogen-activated protein kinase (MAPK pathway). IHC analysis showed that patients with higher MET protein expression had a significantly shorter overall survival. In addition, silencing of MET caused an upregulation of EGFR and p-AKT, which was abrogated by concomitant silencing of MET and EGFR in CMM cells resistant to MAPK-targeting drugs. We therefore explored novel treatment strategies using clinically approved drugs afatinib (ERBB family inhibitor) and crizotinib (MET inhibitor), to simultaneously block MET and ERBB family RTKs. The effects of the combination were assessed in cell culture and spheroid models using established CMM and patient-derived short-term cell lines, and an in vivo xenograft mouse model. The combination had a synergistic effect, promoting cell death, concomitant with a potent downregulation of migratory and invasive capacity independent of their BRAF/NRAS mutational status. Furthermore, the combination attenuated tumor growth rate, as ascertained by the significant reduction of Ki67 expression and induced DNA damage in vivo. Importantly, this combination therapy had minimal therapy-related toxicity in mice. Lastly, the cell cycle G2 checkpoint kinase WEE1 and the RTK IGF1R, non-canonical targets, were altered upon exposure to the combination. Knockdown of WEE1 abrogated the combination-mediated effects on cell migration and proliferation in BRAF mutant BRAF inhibitor-sensitive cells, whereas WEE1 silencing alone inhibited cell migration in NRAS mutant cells. In summary, our results show that afatinib and crizotinib in combination is a promising alternative targeted therapy option for CMM patients, irrespective of BRAF/NRAS mutational status, as well as for cases where resistance has developed towards BRAF inhibitors.

The RTK Interactome: Overview and Perspective on RTK Heterointeractions

Receptor tyrosine kinases (RTKs) play important roles in cell growth, motility, differentiation, and survival. These single-pass membrane proteins are grouped into subfamilies based on the similarity of their extracellular domains. They are generally thought to be activated by ligand binding, which promotes homodimerization and then autophosphorylation in trans. However, RTK interactions are more complicated, as RTKs can interact in the absence of ligand and heterodimerize within and across subfamilies. Here, we review the known cross-subfamily RTK heterointeractions and their possible biological implications, as well as the methodologies which have been used to study them. Moreover, we demonstrate how thermodynamic models can be used to study RTKs and to explain many of the complicated biological effects which have been described in the literature. Finally, we discuss the concept of the RTK interactome: a putative, extensive network of interactions between the RTKs. This RTK interactome can produce unique signaling outputs; can amplify, inhibit, and modify signaling; and can allow for signaling backups. The existence of the RTK interactome could provide an explanation for the irreproducibility of experimental data from different studies and for the failure of some RTK inhibitors to produce the desired therapeutic effects. We argue that a deeper knowledge of RTK interactome thermodynamics can lead to a better understanding of fundamental RTK signaling processes in health and disease. We further argue that there is a need for quantitative, thermodynamic studies that probe the strengths of the interactions between RTKs and their ligands and between different RTKs.