Sitravatinib is a potential EGFR inhibitor and induce a new death phenotype in Glioblastoma

Glioblastoma (GBM) is a highly lethal neurological tumor that presents significant challenge for clinicians due to its heterogeneity and high mortality rate. Despite extensive research, there is currently no effective drug treatment available for GBM. Research evidence has consistently demonstrated that the epidermal growth factor receptor (EGFR) promotes tumor progression and is associated with poor prognosis in several types of cancer. In glioma, EGFR abnormal amplification is reported in approximately 40% of GBM patients, with overexpression observed in 60% of cases, and deletion or mutation in 24% to 67% of patients. In our study, Sitravatinib, a potential EGFR inhibitor, was identified through molecular docking screening based on protein structure. The targeting of EGFR and the tumor inhibitory effect of Sitravatinib on glioma were verified through cellular and in vivo experiments, respectively. Our study also revealed that Sitravatinib effectively inhibited GBM invasive and induced DNA damage and cellular senescence. Furthermore, we observed a novel cell death phenotype induced by Sitravatinib, which differed from previously reported programmed death patterns such as apoptosis, pyroptosis, ferroptosis, and necrosis.

Blood HER2 and Uromodulin as Causal Mediators of CKD

Many biomarkers have been epidemiologically linked with CKD; however, the possibility that such associations are due to reverse causation or confounding limits the utility of these biomarkers. To overcome this limitation, we used a Mendelian randomization (MR) approach to identify causal mediators of CKD. We performed MR by first identifying genetic determinants of 227 serum protein biomarkers assayed in 4147 participants of the Outcome Reduction with Initial Glargine Intervention (ORIGIN) trial who had early or prediabetes, and assessing the effects of these biomarkers on CKD in the CKD genetics consortium (n=117,165; 12,385 cases) using the inverse-variance weighted (fixed-effects) method. We then estimated the relationship between the serum concentration of each biomarker identified and incident CKD in ORIGIN participants. MR identified uromodulin (UMOD) and human EGF receptor 2 (HER2) as novel, causal mediators of CKD (UMOD: odds ratio [OR], 1.30 per SD; 95% confidence interval [95% CI], 1.25 to 1.35; P<5×10^-20; HER2: OR, 1.30 per SD; 95% CI, 1.14 to 1.48; P=8.0×10^-5). Consistent with these findings, blood HER2 concentration associated with CKD events in ORIGIN participants (OR, 1.07 per SD; 95% CI, 1.01 to 1.13; P=0.01). Additional exploratory MR analyses identified angiotensin-converting enzyme (ACE) as a regulator of HER2 levels (β=0.13 per SD; 95% CI, 0.08 to 0.16; P=2.5×10^-7). This finding was corroborated by an inverse relationship between ACE inhibitor use and HER2 levels. Thus, UMOD and HER2 are independent causal mediators of CKD in humans, and serum HER2 levels are regulated in part by ACE. These biomarkers are potential therapeutic targets for CKD prevention.

Novel therapeutic strategies for patients with NSCLC that do not respond to treatment with EGFR inhibitors

INTRODUCTION

Treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) yields tumour responses in non-small cell lung cancer (NSCLC) patients harbouring activating EGFR mutations. However, even in long-lasting responses, resistance to EGFR TKIs invariably occurs.

AREAS COVERED

This review examines resistance mechanisms to EGFR TKI treatment, which mainly arise from secondary EGFR mutations. Other resistance-inducing processes include mesenchymal-epithelial transition factor (MET) amplification, epithelial-mesenchymal transformation, phenotypic change from NSCLC to small-cell lung carcinoma, and modifications in parallel signalling pathways. Current therapeutic strategies to overcome these EGFR TKI resistance mechanisms focus on the inhibition or blocking of multiple members of the ErbB family. Several molecules which target multiple ErbB receptors are being investigated in NSCLC and other indications including afatinib, an ErbB Family Blocker, as well as dacomitinib and lapatinib. Novel, non-quinazoline, EGFR inhibitors, that also target EGFR activating and resistance (T790M) mutations, are currently under clinical development. Other therapeutic strategies include inhibition of parallel and downstream pathways, using agents which target heat shock protein (HSP)90 or poly (ADP-ribose) polymerase in addition to mammalian target of rapamycin (mTOR), monoclonal antibodies against the insulin-like growth factor-1 receptor, and fulvestrant-mediated oestrogen receptor regulation.

CONCLUSION

Improved understanding of mechanisms underlying resistance to EGFR TKIs emphasises the importance of a genotype-guided approach to therapy. Elucidation of resistance mechanisms is indeed crucial to target innovative therapeutic approaches and to improve the efficacy of anticancer regimes in NSCLC.

Synthesis and biological evaluation of novel tricyclic oxazine and oxazepine fused quinazolines. Part 1: erlotinib analogs

Two series of novel tricyclic oxazine and oxazepine fused quinazolines have been designed and synthesized. The in vitro antitumor effect of the title compounds was screened on N87, A431, H1975, BT474 and Calu-3 cell lines. Compared to erlotinib and gefitinib, compounds 1a-1h were found to demonstrate more potent antitumor activities. Several derivatives could counteract EGF-induced phosphorylation of EGFR in cells, and their potency was comparable to the reference compounds. Compounds 1a-1h were chosen for further evaluation of EGFR and HER2 in vitro kinase inhibitory activity. Compounds 1b-1f, 1h effectively inhibited the in vitro kinase activity of EGFR and HER2 with similar efficacy as erlotinib and gefitinib.

Mathematical simulation of membrane protein clustering for efficient signal transduction

Initiation and propagation of cell signaling depend on productive interactions among signaling proteins at the plasma membrane. These diffusion-limited interactions can be influenced by features of the membrane that introduce barriers, such as cytoskeletal corrals, or microdomains that transiently confine both transmembrane receptors and membrane-tethered peripheral proteins. Membrane topographical features can lead to clustering of receptors and other membrane components, even under very dynamic conditions. This review considers the experimental and mathematical evidence that protein clustering impacts cell signaling in complex ways. Simulation approaches used to consider these stochastic processes are discussed.

Molecular pathology of lung cancer: key to personalized medicine

The majority of lung adenocarcinoma patients with epidermal growth factor receptor- (EGFR) mutated or EML4-ALK rearrangement-positive tumors are sensitive to tyrosine kinase inhibitors. Both primary and acquired resistance in a significant number of those patients to these therapies remains a major clinical problem. The specific molecular mechanisms associated with tyrosine kinase inhibitor resistance are not fully understood. Clinicopathological observations suggest that molecular alterations involving so-called 'driver mutations' could be used as markers that aid in the selection of patients most likely to benefit from targeted therapies. In this review, we summarize recent developments involving the specific molecular mechanisms and markers that have been associated with primary and acquired resistance to EGFR-targeted therapy in lung adenocarcinomas. Understanding these mechanisms may provide new treatment avenues and improve current treatment algorithms.

Mechanistic insights into acquired drug resistance in epidermal growth factor receptor mutation-targeted lung cancer therapy

Oncogenic mutation of epidermal growth factor receptor kinase domain is strongly associated with clinical response to tyrosine kinase inhibitors in non-small-cell lung carcinoma. Despite an initial encouraging response, patients eventually develop drug resistance and relapse. Great efforts have been made to identify the molecular mechanisms of drug resistance. With the recognition of cancer as a whole complex system, here it is proposed that cancer may evolve drug resistance in a cancer-cell-autonomous manner as well as a non-cancer-cell-autonomous manner. The former mainly arises at three levels: the robustness of the epidermal growth factor receptor signaling network; cancer epigenetic changes; or cancer genetic alteration, which may be dependent on the therapeutics methods and treatment duration. As cancer stroma plays an essential role in lung cancerigenesis, we further discuss the potential mechanisms for drug resistance development in a non-cancer-cell-autonomous manner, which may arise from the interaction between cancer cells and cancer stroma, including stromal cells and extracellular matrix.

Functional proteomics to dissect tyrosine kinase signalling pathways in cancer

Advances in the generation and interpretation of proteomics data have spurred a transition from focusing on protein identification to functional analysis. Here we review recent proteomics results that have elucidated new aspects of the roles and regulation of signal transduction pathways in cancer using the epidermal growth factor receptor (EGFR), ERK and breakpoint cluster region (BCR)-ABL1 networks as examples. The emerging theme is to understand cancer signalling as networks of multiprotein machines which process information in a highly dynamic environment that is shaped by changing protein interactions and post-translational modifications (PTMs). Cancerous genetic mutations derange these protein networks in complex ways that are tractable by proteomics.