Discovery of 4-methyl-N-(4-((4-methylpiperazin- 1-yl)methyl)-3-(trifluoromethyl)phenyl)-3-((6-(pyridin-3-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-yl)-oxy)benzamide as a potent inhibitor of RET and its gatekeeper mutant

Structure-Based QSAR Modeling of RET Kinase Inhibitors from 49 Different 5,6-Fused Bicyclic Heteroaromatic Cores to Patent-Driven Validation

RET receptor tyrosine kinase is crucial for nerve and tissue development but can be an important oncogenic driver. This study focuses on exploring the design principles of potent RET inhibitors through molecular docking and 3D-QSAR modeling of 5,6-fused bicyclic heteroaromatic derivatives. First of all, RET inhibitors of 49 different bicyclic substructures were collected from five different data sources and selected through molecular docking simulations. QSAR models were built from the 3399 conformers of 952 RET inhibitors using the partial least-squares method and statistically evaluated. The optimal QSAR model exhibited high predictive performance, with R 2 (of training data) and Q 2 (of test data) values of 0.801 and 0.794, respectively, effectively predicting known inhibitors. The optimal model was doubly verified by patent-filed RET inhibitors as the out-of-set data to demonstrate acceptable residual analysis results. Moreover, feature importance analysis of the QSAR model outlined the impact of substituent characteristics on the inhibitory activity within the 5,6-fused bicyclic heteroaromatic core structures. Furthermore, the relationship between structure and inhibitory activity was successfully applied to the RET screening of known clinical and nonclinical kinase inhibitors to afford accurate off-target prediction.

Discovery of 7-(1-methyl-1H-pyrazol-4-yl)-1,6-naphthyridine derivatives as potent inhibitors of rearranged during transfection (RET) and RET solvent-front mutants for overcoming selpercatinib resistance

Rearranged during transfection kinase (RET) inhibition has been considered a promising therapeutic approach for treatment of a variety of cancers. However, the clinical therapeutic benefits of the second-generation RET inhibitor selpercatinib are greatly compromised by acquired resistance mediated by solvent-front mutations (e.g., RETG810 R/S/C). Herein, we report a class of 7-(1-methyl-1H-pyrazol-4-yl)-1,6-naphthyridine derivatives as potent RET and RET solvent-front mutant inhibitors for overcoming selpercatinib resistance. The representative compound 20p exhibited excellent in vitro inhibitory activities against solvent-front mutations (RETG810R, RETG810S, and RETG810C) with low nanomolar range (IC50 of 5.7-8.3 nM), which was 15-29-fold more potent than selpercatinib (IC50 of 95.3-244.1 nM). Additionally, 20p exhibited acceptable pharmacokinetic properties with oral bioavailability of 30.4 %. Importantly, 20p exhibited highly impressive antitumor potency in both a Ba/F3-KIF5B-RETWT-derived xenograft mouse model and a selpercatinib-resistant Ba/F3-KIF5B-RETG810R-positive mutant xenograft mouse model. Overall, 20p represents a novel and promising drug lead for overcoming RET solvent-front mutation-based resistance to selpercatinib.

Current scenario of fused pyrimidines with in vivo anticancer therapeutic potential

Cancer, characterized by uncontrolled cell growth and metastasis, is responsible for nearly one in six deaths and represents a severe threat to public health worldwide. Chemotherapy can substantially improve the quality of life and survival of patients with cancer, but anticancer chemotherapeutics are associated with a range of adverse effects. Moreover, almost all currently available anticancer chemotherapeutics could develop drug resistance over a period of time of application in cancer patients and ultimately lead to cancer relapse and death in 90% of patients, creating an urgent need to develop new anticancer agents. Fused pyrimidines trait the inextricable part of DNA and RNA and are vital in numerous biological processes. Fused pyrimidines can act on various biological cancer targets and have the potential to address drug resistance. In addition, more than 20 fused pyrimidines have already been approved for clinical treatment of different cancers and occupy a prominent place in the current therapeutic arsenal, revealing that fused pyrimidines are privileged scaffolds for the development of novel anticancer chemotherapeutics. The purpose of this review is to summarize the current scenario of fused pyrimidines with in vivo anticancer therapeutic potential along with their acute toxicity, metabolic profiles as well as pharmacokinetic properties, toxicity and mechanisms of action developed from 2020 to the present to facilitate further rational exploitation of more effective candidates.

Unraveling the Promise of RET Inhibitors in Precision Cancer Therapy by Targeting RET Mutations

Over the past decades, the role of rearranged during transfection (RET) alterations in tumorigenesis has been firmly established. RET kinase inhibition is an essential therapeutic target in patients with RET-altered cancers. In clinical practice, initial efficacy can be achieved in patients through the utilization of multikinase inhibitors (MKIs) with RET inhibitory activity. However, the effectiveness of these MKIs is impeded by the adverse events associated with off-target effects. Recently, many RET-selective inhibitors, characterized by heightened specificity and potency, have been developed, representing a substantial breakthrough in the field of RET precision oncology. This Perspective focuses on the contemporary understanding of RET mutations, recent advancements in next-generation RET inhibitors, and the challenges associated with resistance to RET inhibitors. It provides valuable insights for the development of next-generation MKIs and selective RET inhibitors.

Advances and challenges in the treatment of lung cancer

Lung cancer accounts for a relatively high proportion of malignant tumors. As the most prevalent type of lung cancer, non-small cell lung cancer (NSCLC) is characterized by high morbidity and mortality. Presently, the arsenal of treatment strategies encompasses surgical resection, chemotherapy, targeted therapy and radiotherapy. However, despite these options, the prognosis remains distressingly poor with a low 5-year survival rate. Therefore, it is urgent to pursue a paradigm shift in treatment methodologies. In recent years, the advent of sophisticated biotechnologies and interdisciplinary integration has provided innovative approaches for the treatment of lung cancer. This article reviews the cutting-edge developments in the nano drug delivery system, molecular targeted treatment system, photothermal treatment strategy, and immunotherapy for lung cancer. Overall, by systematically summarizing and critically analyzing the latest progress and current challenges in these treatment strategies of lung cancer, we aim to provide a theoretical basis for the development of novel drugs for lung cancer treatment, and thus improve the therapeutic outcomes for lung cancer patients.

Discovery of 3,5-diaryl-1H-pyrazol-based ureas as potent RET inhibitors

Rearranged during transfection (RET) is a promising target for antitumor drug development. Multikinase inhibitors (MKI) have been developed for RET-driven cancers but displayed limited efficacy in disease control. Two selective RET inhibitors were approved by FDA in 2020 and proved potent clinical efficacy. However, the discovery of novel RET inhibitors with high target selectivity and improved safety is still highly desirable. Herein, we reported a class of 3,5-diaryl-1H-pyrazol-based ureas as new RET inhibitors. The representative compounds 17a/b displayed high selectivity to other kinases, and potently inhibited isogenic BaF3-CCDC6-RET cells harboring wild-type, or gatekeeper mutation (V804M). They also displayed moderate potency against BaF3-CCDC6-RET-G810C with solvent-front mutation. Compound 17b showed better pharmacokinetics properties and demonstrated promising oral in vivo antitumor efficacy in a BaF3-CCDC6-RET-V804M xenograft model. It may be utilized as a new lead compound for further development.

Design, synthesis and biological characteristics of pyrazolo[3,4-d]pyrimidine derivatives as potential VEGFR-2 inhibitors

Aim: Several VEGFR-2 inhibitors with the structure of [3,4-d]pyrimidine and based on sorafenib were designed and synthesized. Materials & methods: Cytotoxic activity was evaluated by MTT, wound healing and clone formation assays. Cell cycle and apoptosis were analyzed by flow cytometry. Molecular simulation and western blot were also applied. Results: Among them, II-1 significantly inhibited tumor cellular activity (IC₅₀ = 5.90 ± 0.05 μM on HepG2 cells) compared with sorafenib (IC₅₀ = 9.05 ± 0.54 μM on HepG2 cells). Molecular docking demonstrated that II-1 and sorafenib have the same hydrogen binding. Finally, the protein expression of phosphorylated VEGFR-2 was substantially reduced after II-1 treatment. Conclusion: Compound II-1 can inhibit VEFGR-2 activation and is an effective antitumor agent in liver cancer cells.

Pyrazolopyrimidines as attractive pharmacophores in efficient drug design: A recent update

Among the menacing diseases, cancer needs the most attention as millions of people are affected by it worldwide. Genetic and environmental factors play a pivotal role in causing cancer. Although a wide range of underlying mechanisms of cancer has been discovered, efficient treatments have not been discovered to date. Additionally, diseases caused by microbes such as viruses, bacteria, protozoa, and so forth, persistently result in several deaths. Also, inflammation is a major factor that leads to several health issues. For decades, drug design has become a major part of drug discovery and development for curing various diseases. Among the large number of pharmacological agents that have been synthesized, only very few have emerged as efficient drug molecules. Most of them are heterocyclic compounds, which are promising candidates for the design of efficient drug molecules. Furthermore, fused heterocycles showed comparatively stronger pharmacological activities than monocyclic heterocycles. The literature reveals that pyrazolopyrimidines have outstanding biological activity. Hence, here, the diverse pharmacological activities shown by pyrazolopyrimidine derivatives reported in the last 5 years are collated and reviewed systematically. This review is classified into various sections focusing on anticancer, antimicrobial, anti-inflammatory, and enzyme inhibitors. Structure-activity relationships are discussed in brief, which will help researchers design potent pharmacological agents.