Receptor Tyrosine Kinase Phosphorylation Pattern-Based Multidrug Combination Is an Effective Approach for Personalized Cancer Treatment

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

Targeting IGF1R signaling enhances the sensitivity of cisplatin by inhibiting proline and arginine metabolism in oesophageal squamous cell carcinoma under hypoxia

BACKGROUND

Cisplatin (DDP)-based chemotherapy is commonly adopted as the first-line treatment for patients with oesophageal squamous cell carcinoma (OSCC), but the high rate of drug resistance limits its clinical application and the underlying mechanisms at play remain unclear. The aims of this study were to elucidate the role of abnormal signal transmission and metabolism in the chemoresistance of OSCC under hypoxia and to identify targeted drugs that enhance the sensitivity of DDP chemotherapy.

METHODS

Upregulated genes in OSCC were determined by RNA sequencing (RNA-seq), the Cancer Genome Atlas (TCGA) database, immunohistochemistry (IHC), real-time quantitative PCR (RT-qPCR), and western blotting (WB). The clinicopathological significance of insulin-like growth factor-I receptor (IGF1R), argininosuccinate synthetase 1 (ASS1), and pyrroline-5-carboxylate reductase 1 (PYCR1) in OSCC was analysed using tissue micriarray (TMA). Metabolic abnormalities were determined by untargeted metabolomics analysis. The DDP-resistance role of IGF1R, ASS1, and PYCR1 in OSCC was investigated in vitro and in vivo.

RESULTS

Generally, tumour cells exist in a hypoxic microenvironment. By genomic profiling, we determined that IGF1R, as a receptor tyrosine kinase (RTK), was upregulated in OSCC under low-oxygen conditions. Clinically, enhanced IGF1R expression was associated with higher tumour stages and a poorer prognosis in OSCC patients, and its inhibitor, linsitinib, showed synergistic effects with DDP therapy in vivo and in vitro. Since oxygen-deprivation frequently lead to metabolic reprogramming, we further learned via metabolomics analysis that abnormal IGF1R pathways promoted the expression of metabolic enzymes ASS1 and PYCR1 by the transcriptional activity of c-MYC. In detail, enhanced expression of ASS1 promotes arginine metabolism for biological anabolism, whereas PYCR1 activates proline metabolism for redox balance, which maintains the proliferation ability of OSCC cells during DDP treatment under hypoxic conditions.

CONCLUSION

Enhanced expression of ASS1 and PYCR1 via IGF1R pathways rewired arginine and proline metabolism, promoting DDP resistance in OSCC under hypoxia. Linsitinib targeting IGF1R signaling may lead to promising combination therapy options for OSCC patients with DDP resistance.

The tyrosine-kinase inhibitor Nintedanib ameliorates autosomal-dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease and is characterized by progressive growth of fluid-filled cysts. Growth factors binding to receptor tyrosine kinases (RTKs) stimulate cell proliferation and cyst growth in PKD. Nintedanib, a triple RTK inhibitor, targets the vascular endothelial growth-factor receptor (VEGFR), platelet-derived growth-factor receptor (PDGFR), and fibroblast growth-factor receptor (FGFR), and is an approved drug for the treatment of non-small-cell lung carcinoma and idiopathic lung fibrosis. To determine if RTK inhibition using nintedanib can slow ADPKD progression, we tested its effect on human ADPKD renal cyst epithelial cells and myofibroblasts in vitro, and on Pkd1f/fPkhd1Cre and Pkd1RC/RC, orthologous mouse models of ADPKD. Nintedanib significantly inhibited cell proliferation and in vitro cyst growth of human ADPKD renal cyst epithelial cells, and cell viability and migration of human ADPKD renal myofibroblasts. Consistently, nintedanib treatment significantly reduced kidney-to-body-weight ratio, renal cystic index, cystic epithelial cell proliferation, and blood-urea nitrogen levels in both the Pkd1f/fPkhd1Cre and Pkd1RC/RC mice. There was a corresponding reduction in ERK, AKT, STAT3, and mTOR activity and expression of proproliferative factors, including Yes-associated protein (YAP), c-Myc, and Cyclin D1. Nintedanib treatment significantly reduced fibrosis in Pkd1RC/RC mice, but did not affect renal fibrosis in Pkd1f/fPkhd1Cre mice. Overall, these results suggest that nintedanib may be repurposed to effectively slow cyst growth in ADPKD.

Coregulation of pathways in lung cancer patients with EGFR mutation: therapeutic opportunities

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are a frequent class of driver mutations. Single EGFR tyrosine kinase inhibitor (TKI) provides substantial clinical benefit, but almost nil radiographic complete responses. Patients invariably progress, although survival can reach several years with post-treatment therapies, including EGFR TKIs, chemotherapy or other procedures. Endeavours have been clinically oriented to manage the acquisition of EGFR TKI-resistant mutations; however, basic principles on cancer evolution have not been considered in clinical trials. For years, evidence has displayed rapidly adaptive mechanisms of resistance to selective monotherapy, posing several dilemmas for the practitioner. Strict adherence to non-small cell lung cancer (NSCLC) guidelines is not always practical for addressing the clinical progression that EGFR-mutant lung adenocarcinoma patients suffer. The purpose of this review is to highlight regulatory mechanisms and signalling pathways that cause therapy-induced resistance to EGFR TKIs. It suggests combinatorial therapies that target EGFR, as well as potential mechanisms underlying EGFR-mutant NSCLC, alerting the reader to clinical opportunities that may lead to a deeper and more durable response. Molecular reprogramming contributes to EGFR TKI resistance, and the compiled information is relevant in understanding the development of new combined targeted strategies in EGFR-mutant NSCLC.

Phospho-Protein Arrays as Effective Tools for Screening Possible Targets for Kinase Inhibitors and Their Use in Precision Pediatric Oncology

The specific targeting of signal transduction by low-molecular-weight inhibitors or monoclonal antibodies represents a very promising personalized treatment strategy in pediatric oncology. In this study, we present the successful and clinically relevant use of commercially available phospho-protein arrays for analyses of the phosphorylation profiles of a broad spectrum of receptor tyrosine kinases and their downstream signaling proteins in tumor tissue samples. Although these arrays were made for research purposes on human biological samples, they have already been used by several authors to profile various tumor types. Our study performed a systematic analysis of the advantages and pitfalls of the use of this method for personalized clinical medicine. In certain clinical cases and their series, we demonstrated the important aspects of data processing and evaluation, the use of phospho-protein arrays for single sample and serial sample analyses, and the validation of obtained results by immunohistochemistry, as well as the possibilities of this method for the hierarchical clustering of pediatric solid tumors. Our results clearly show that phospho-protein arrays are apparently useful for the clinical consideration of druggable molecular targets within a specific tumor. Thus, their potential validation for diagnostic purposes may substantially improve the personalized approach in the treatment of relapsed or refractory solid tumors.

Immunotherapies and Targeted Therapies in the Treatment of Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer deaths, and while mortality has largely improved in the developed world, five-year survival for metastatic disease remains dismally low at only 15%. Fortunately, nearly a dozen targeted therapies and immunotherapies have been FDA approved in the past decade for certain patient profiles with metastatic CRC (mCRC), and many others are under development. Checkpoint inhibitors such as pembrolizumab have proven effective at extending survival for mismatch repair (MMR)-deficient and high microsatellite instability (MSI) mCRC patients. In combination with chemotherapy in first- and second-line treatment, antiangiogenic (anti-vascular endothelial growth factor (anti-VGEF)) agent bevacizumab has been shown to increase mCRC survival. Anti-epidermal growth factor receptor (anti-EGFR) agents panitumumab and cetuximab, in combination with chemotherapy, have also prolonged survival among KRAS and all RAS wild-type mCRC patients. Among these patients, anti-EGFR therapy has been found to be more efficacious than bevacizumab. Improved selectivity has allowed small-molecule receptor tyrosine kinase (RTK) inhibitors to target VEGF and EGFR with greater efficacy and tolerability. Combinations of immunotherapies, RTKs, monoclonal antibodies, and cytotoxic drugs are being investigated to provide broad-spectrum protection against relapse by simultaneously targeting many cancer hallmarks. Lastly, human epidermal growth factor receptor 2 (HER2) therapy has shown promise for HER2-positive mCRC patients, though larger clinical trials are required to secure FDA approval.

Virtual Screening Guided Design, Synthesis and Bioactivity Study of Benzisoselenazolones (BISAs) on Inhibition of c-Met and Its Downstream Signalling Pathways

c-Met is a transmembrane receptor tyrosine kinase and an important therapeutic target for anticancer drugs. In this study, we designed a small library containing 300 BISAs molecules that consisted of carbohydrates, amino acids, isothiourea, tetramethylthiourea, guanidine and heterocyclic groups and screened c-Met targeting compounds using docking and MM/GBSA. Guided by virtual screening, we synthesised a series of novel compounds and their activity on inhibition of the autophosphorylation of c-Met and its downstream signalling pathway proteins were evaluated. We found a panel of benzisoselenazolones (BISAs) obtained by introducing isothiourea, tetramethylthiourea and heterocyclic groups into the C-ring of Ebselen, including 7a, 7b, 8a, 8b and 12c (with IC50 values of less than 20 μM in MET gene amplified lung cancer cell line EBC-1), exhibited more potent antitumour activity than Ebselen by cell growth assay combined with in vitro biochemical assays. In addition, we also tested the antitumour activity of three cancer cell lines without MET gene amplification/activation, including DLD1, MDA-MB-231 and A549. The neuroblastoma SK-N-SH cells with HGF overexpression which activates MET signalling are sensitive to MET inhibitors. The results reveal that our compounds may be nonspecific multitarget kinase inhibitors, just like type-II small molecule inhibitors. Western blot analysis showed that these inhibitors inhibited autophosphorylation of c-MET, and its downstream signalling pathways, such as PI3K/AKT and MARK/ERK. Results suggest that bensoisoselenones can be used as a scaffold for the design of c-Met inhibiting drug leads, and this study opens up new possibilities for future antitumour drug design.

Emodin Sensitizes Hepatocellular Carcinoma Cells to the Anti-Cancer Effect of Sorafenib through Suppression of Cholesterol Metabolism

Reduced therapeutic efficacy of sorafenib, a first-generation multikinase inhibitor, is often observed during the treatment of advanced hepatocellular carcinoma (HCC). Emodin is an active component of Chinese herbs, and is effective against leukemia, lung cancer, colon cancer, pancreatic cancer, and HCC; however, the sensitizing effect of emodin on sorafenib-based HCC therapy has not been evaluated. Here, we demonstrate that emodin significantly improved the anti-cancer effect of sorafenib in HCC cells, such as HepG2, Hep3B, Huh7, SK-HEP-1, and PLC/PRF5. Mechanistically, emodin inhibits sterol regulatory element-binding protein-2 (SREBP-2) transcriptional activity, which suppresses cholesterol biosynthesis and oncogenic protein kinase B (AKT) signaling. Additionally, attenuated cholesterol synthesis and oncogenic AKT signaling inactivated signal transducer and activator of transcription 3 (STAT3), an oncogenic transcription factor. Furthermore, emodin synergistically increased cell cycle arrest in the G1 phase and apoptotic cells in the presence of sorafenib. Animal models xenografted with HepG2 or SK-HEP-1 cells also showed that the combination of emodin and sorafenib was sufficient to inhibit tumor growth. Overall, these results suggested that the combination of emodin and sorafenib may offer a potential therapy for patients with advanced HCC.

Common Co-activation of AXL and CDCP1 in EGFR-mutation-positive Non-smallcell Lung Cancer Associated With Poor Prognosis

Epidermal growth factor receptor (EGFR)-mutation-positive non-small cell lung cancer (NSCLC) is incurable, despite high rates of response to EGFR tyrosine kinase inhibitors (TKIs). We investigated receptor tyrosine kinases (RTKs), Src family kinases and focal adhesion kinase (FAK) as genetic modifiers of innate resistance in EGFR-mutation-positive NSCLC. We performed gene expression analysis in two cohorts (Cohort 1 and Cohort 2) of EGFR-mutation-positive NSCLC patients treated with EGFR TKI. We evaluated the efficacy of gefitinib or osimertinib with the Src/FAK/Janus kinase 2 (JAK2) inhibitor, TPX0005 in vitro and in vivo. In Cohort 1, CUB domain-containing protein-1 (CDCP1) was an independent negative prognostic factor for progression-free survival (hazard ratio of 1.79, p = 0.0407) and overall survival (hazard ratio of 2.23, p = 0.0192). A two-gene model based on AXL and CDCP1 expression was strongly associated with the clinical outcome to EGFR TKIs, in both cohorts of patients. Our preclinical experiments revealed that several RTKs and non-RTKs, were up-regulated at baseline or after treatment with gefitinib or osimertinib. TPX-0005 plus EGFR TKI suppressed expression and activation of RTKs and downstream signaling intermediates. Co-expression of CDCP1 and AXL is often observed in EGFR-mutation-positive tumors, limiting the efficacy of EGFR TKIs. Co-treatment with EGFR TKI and TPX-0005 warrants testing.

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AXL and CDCP1 are co-expressed in treatment-naïve EGFR-mutation-positive NSCLC patients.

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AXL and CDCP1 are related to shorter progression-free survival with EGFR inhibitors and shorter overall survival.

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Src family kinases and YAP1 are regulatory nodes for AXL and CDCP1 expression.

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The combination of EGFR TKI with TPX-0005 is synergistic in EGFR-mutation-positive lung tumors in culture and in vivo.

We explore the molecular changes that occur after the application of an EGFR inhibitor in EGFR-mutation positive tumors. The tumors do not acquire secondary drivers to overcome a primary driver but, counter-regulatory nodes observable before treatment, are immediately made apparent by pathway-specific intervention. The expression of the receptor tyrosine kinase AXL and the transmembrane protein CDCP1 in baseline samples of EGFR-mutation positive NSCLC patients can provide us with information on the treatment outcome. The upfront combination of an EGFR inhibitor with a multikinase inhibitor, that controls the regulatory nodes for RTKs activation, is a therapeutic approach that deserves to be further explored.