Discovery and Optimization of 2-Amino-4-methylquinazoline Derivatives as Highly Potent Phosphatidylinositol 3-Kinase Inhibitors for Cancer Treatment

Design, synthesis and evaluation of a fluorescent PI3K inhibitor as a dual-function agent toward Cancer Theranostics

The development of PI3K-targeted therapeutics has advanced significantly, yet molecular tools capable of simultaneous kinase inhibition and real-time visualization of drug distribution remain limited. Herein, we describe the rational design, synthesis, and biological evaluation of a novel fluorescent PI3K inhibitor (compound 1) that incorporates a 4-methylquinazoline pharmacophore conjugated to fluorescein isothiocyanate (FITC) through a piperazine linker. 1 demonstrated potent PI3K enzymatic inhibition and exhibited significant antiproliferative effects against HGC-27 and MCF-7 cancer cell lines. Mechanistic investigations revealed that 1 effectively suppresses DNA synthesis, triggers G0/G1 cell cycle arrest, and disrupts mitochondrial architecture. Fluorescence-based cellular and in vivo imaging studies demonstrated the compound's preferential cytoplasmic localization and tumor-targeting properties. This dual-function inhibitor not only advances PI3K-targeted drug discovery but also provides a valuable tool for real-time monitoring of drug distribution, representing a promising addition to the growing field of cancer theranostics.

Substrate-Based Ligand Design for Phenazine Biosynthesis Enzyme PhzF

The phenazine pyocyanin is an important virulence factor of the pathogen Pseudomonas aeruginosa, which is on the WHO list of antibiotic resistant "priority pathogens". In this study the isomerase PhzF, a key bacterial enzyme of the pyocyanin biosynthetic pathway, was investigated as a pathoblocker target. The aim of the pathoblocker strategy is to reduce the virulence of the pathogen without killing it, thus preventing the rapid development of resistance. Based on crystal structures of PhzF, derivatives of the inhibitor 3-hydroxyanthranilic acid were designed. Co-crystal structures of the synthesized derivatives with PhzF revealed spacial limitations of the binding pocket of PhzF in the closed conformation. In contrast, ligands aligned to the open conformation of PhzF provided more room for structural modifications. The intrinsic fluorescence of small 3-hydroxyanthranilic acid derivatives enabled direct affinity determinations using FRET assays. The analysis of structure-activity relationships showed that the carboxylic acid moiety is essential for binding to the target enzyme. The results of this study provide fundamental structural insights that will be useful for the design of PhzF-inhibitors.

Recent Progress in Regulating the Activity of Enzymes with Photoswitchable Inhibitors

Photoregulation of biomolecules has become crucial tools in chemical biology, because light enables access under mild conditions and with delicate spatiotemporal control. The control of enzyme activity in a reversible way is a challenge. To achieve it, a facile approach is to use photoswitchable inhibitors. This review highlights recent progress in photoswitchable inhibitors based on azobenzenes units. The progress suggests that the incorporation of an azobenzene unit to a known inhibitor is an effective method for preparing a photoswitchable inhibitor, and with these photoswitchable inhibitors, the activity of enzymes can be regulated by optical control, which is valuable in both basic science and therapeutic applications.

Design, synthesis and biological evaluation of a novel PSMA-PI3K small molecule drug conjugate

Small molecule drug conjugates are an emerging targeted therapy for cancer treatment. Building upon the overexpressed prostate-specific membrane antigen (PSMA) in prostate cancer, we herein report the design and synthesis of a novel PSMA-PI3K small molecule drug conjugate 1. Conjugate 1 demonstrates potent inhibition against PI3K with an IC50 value of 0.40 nM and simultaneously targets PSMA, giving rise to selective growth inhibition activity for PSMA-positive cancer cells. Conjugate 1 also potently inhibits the phosphorylation of PI3K main downstream effectors and arrests the cell cycle in the G0/G1 phase in PSMA-positive 22Rv1 prostate cancer cells. Further in vivo evaluation shows that conjugate 1 has favorable efficacy and tolerability in a 22Rv1 xenograft model, demonstrating its potential application in targeted cancer therapy.

Pharmacokinetics of IMM-H012 in rats using ultra-performance liquid chromatography-tandem mass spectrometry

The present study examined the pharmacokinetics of IMM-H012 in rat plasma, utilizing ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Internal standard cilostazol was employed, and plasma samples were processed using acetonitrile precipitation. A mobile phase (acetonitrile-0.1% formic acid in water) with gradient elution was used to achieve chromatographic separation using a UPLC BEH C18 column. In multiple reaction monitoring mode, electrospray ionization MS/MS was utilized in positive ionization mode. Based on findings, the lower limit of quantification was 2 ng/mL, and the linearity of IMM-H012 in rat plasma was found to be acceptable within the range of 2-2000 ng/mL (R2 > 0.995). The intra-day and inter-day precision relative standard deviation was less than 14% of IMM-H012 in rat plasma. The matrix effect was within the range of 102%-107%, and the accuracy ranged from 92% to 113%. Pharmacokinetics of IMM-H012 in rats after oral administration were successfully studied using UPLC-MS/MS.

Design, synthesis and evaluation of 2, 6, 8-substituted Imidazopyridine derivatives as potent PI3Kα inhibitors

Inhibition of PI3K pathway has become a desirable strategy for cancer treatment. In this work, a series of 2, 6, 8-substituted Imidazo[1,2-a]pyridine derivatives were designed and screened for their activities against PI3Kα and a panel of PI3Kα-addicted cancer cells. Among them, compound 35 was identified as a PI3Kα inhibitor with nanomolar potency as well as acceptable antiproliferative activity. Flow cytometry analysis confirmed 35 induced cell cycle arrest and apoptosis in T47D cells. In addition, it also showed desirable in vitro ADME properties. The design, synthesis, and SAR exploration of 35 are described within.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

Design, synthesis and bioevaluation of PI3Kα-selective inhibitors as potential colorectal cancer drugs

The dysregulation of the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin signaling pathway has been implicated in various human cancers, and isoform-selective inhibitors targeting PI3Kα have received significant interest in recent years. In this study, we have designed and synthesized three series of substituted benzoxazole derivatives based on the clinical candidate TAK-117 (8a). A detailed structure-activity relationship (SAR) study has identified the optimal compound 18a bearing a quinoxaline scaffold. Compared to the control 8a, 18a exhibited 4.4-fold more potent inhibitory activity against PI3Kα (IC50: 2.5 vs 11 nM) and better isoform-selective profiles over other PI3Ks. In addition, 18a showed a 1.5-fold more potent antiproliferative effect against HCT-116 cell lines (IC50: 3.79 vs 5.80 μM) and a better selectivity over the normal tissue cells. The potential antitumor mechanism and in vitro metabolic stability of 18a were also investigated. Notably, pharmacokinetic assays indicated that 18a had a higher plasma exposure, a higher maximum concentration and shorter elimination time compared to 8a.

Targeting the PI3K/AKT/mTOR Signaling Pathway in the Treatment of Human Diseases: Current Status, Trends, and Solutions

The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is one of the most important intracellular pathways involved in cell proliferation, growth, differentiation, and survival. Therefore, this route is a prospective biological target for treating various human diseases, such as tumors, neurodegenerative diseases, pulmonary fibrosis, and diabetes. An increasing number of clinical studies emphasize the necessity of developing novel molecules targeting the PI3K/AKT/mTOR pathway. This review focuses on recent advances in ATP-competitive inhibitors, allosteric inhibitors, covalent inhibitors, and proteolysis-targeting chimeras against the PI3K/AKT/mTOR pathway, and highlights possible solutions for overcoming the toxicities and acquired drug resistance of currently available drugs. We also provide recommendations for the future design and development of promising drugs targeting this pathway.

Bioevaluation of a dual PI3K/HDAC inhibitor for the treatment of diffuse large B-cell lymphoma

The synergistic anti-tumor effect by simultaneous inhibitions of PI3K and HDAC has been verified to provide the rationality of PI3K/HDAC dual inhibitors for cancer treatment. Notably, the outstanding effect of PI3K/HDAC dual inhibitors against DLBCL has been paid much attention, especially for RR-DLBCL. Our previously reported 4-methylquinazoine scaffold based PI3K/HDAC dual inhibitors could suppress the growth of solid tumors and hematologic malignancies both in vitro and in vivo, validating the potential as new therapeutic agents for cancer. In this research, we further investigated the anti-tumor activity of one of our compounds against DLBCL cell lines and in vivo zebrafish xenograft model as well as the underlying mechanism, hoping to provide a novel therapeutic agent for treating DLBCL.

Glioblastoma: Current Status, Emerging Targets, and Recent Advances

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

New kinase and HDAC hybrid inhibitors: recent advances and perspectives

Cancer is the second most common cause of death worldwide. It can easily acquire resistance to treatments, demanding new therapeutic strategies, such as simultaneous inhibition of kinase and HDAC enzymes with hybrid inhibitors. Different approaches to this have varied according to their targets, with a few common trends, such as the usage of heterocycle scaffolds for kinase interaction, especially pyrimidine and quinazolines, and hydroxamic acids and benzamides for HDAC inhibition. Besides the hybrid compounds developed focusing on the inhibition tyrosine kinase and receptor tyrosine kinase, many advances have occurred in the development of serine-threonine kinase/HDAC and lipid kinase/HDAC novel compounds. Here, the latest strategies employed in this research area will be reviewed, alongside trends in inhibitor design, and observed gaps will be punctuated.

Quinazoline Based HDAC Dual Inhibitors as Potential Anti-Cancer Agents

Cancer is the most devastating disease and second leading cause of death around the world. Despite scientific advancements in the diagnosis and treatment of cancer which can include targeted therapy, chemotherapy, endocrine therapy, immunotherapy, radiotherapy and surgery in some cases, cancer cells appear to outsmart and evade almost any method of treatment by developing drug resistance. Quinazolines are the most versatile, ubiquitous and privileged nitrogen bearing heterocyclic compounds with a wide array of biological and pharmacological applications. Most of the anti-cancer agents featuring quinazoline pharmacophore have shown promising therapeutic activity. Therefore, extensive research is underway to explore the potential of these privileged scaffolds. In this context, a molecular hybridization approach to develop hybrid drugs has become a popular tool in the field of drug discovery, especially after witnessing the successful results during the past decade. Histone deacetylases (HDACs) have emerged as an important anti-cancer target in the recent years given its role in cellular growth, gene regulation, and metabolism. Dual inhibitors, especially based on HDAC in particular, have become the center stage of current cancer drug development. Given the growing significance of dual HDAC inhibitors, in this review, we intend to compile the development of quinazoline based HDAC dual inhibitors as anti-cancer agents.

A novel PI3K inhibitor XH30 suppresses orthotopic glioblastoma and brain metastasis in mice models

Glioblastoma is carcinogenesis of glial cells in central nervous system and has the highest incidence among primary brain tumors. Brain metastasis, such as breast cancer and lung cancer, also leads to high mortality. The available medicines are limited due to blood–brain barrier. Abnormal activation of phosphatidylinositol 3-kinases (PI3K) signaling pathway is prevalent in glioblastoma and metastatic tumors. Here, we characterized a 2-amino-4-methylquinazoline derivative XH30 as a potent PI3K inhibitor with excellent anti-tumor activity against human glioblastoma. XH30 significantly repressed the proliferation of various brain cancer cells and decreased the phosphorylation of key proteins of PI3K signaling pathway, induced cell cycle arrest in G1 phase as well. Additionally, XH30 inhibited the migration of glioma cells and blocked the activation of PI3K pathway by interleukin-17A (IL-17A), which increased the migration of U87MG. Oral administration of XH30 significantly suppressed the tumor growth in both subcutaneous and orthotopic tumor models. XH30 also repressed tumor growth in brain metastasis models of lung cancers. Moreover, XH30 reduced IL-17A and its receptor IL-17RA in vivo. These results indicate that XH30 might be a potential therapeutic drug candidate for glioblastoma migration and brain metastasis.

The PI3K Inhibitor XH30 Enhances Response to Temozolomide in Drug-Resistant Glioblastoma via the Noncanonical Hedgehog Signaling Pathway

Glioblastoma multiforme (GBM) is the most common malignant tumor of the central nervous system. Temozolomide (TMZ)-based adjuvant treatment has improved overall survival, but clinical outcomes remain poor; TMZ resistance is one of the main reasons for this. Here, we report a new phosphatidylinositide 3-kinase inhibitor, XH30; this study aimed to assess the antitumor activity of this compound against TMZ-resistant GBM. XH30 inhibited cell proliferation in TMZ-resistant GBM cells (U251/TMZ and T98G) and induced cell cycle arrest in the G1 phase. In an orthotopic mouse model, XH30 suppressed TMZ-resistant tumor growth. XH30 was also shown to enhance TMZ cytotoxicity both in vitro and in vivo. Mechanistically, the synergistic effect of XH30 may be attributed to its repression of the key transcription factor GLI1 via the noncanonical hedgehog signaling pathway. XH30 reversed sonic hedgehog-triggered GLI1 activation and decreased GLI1 activation by insulin-like growth factor 1 via the noncanonical hedgehog signaling pathway. These results indicate that XH30 may represent a novel therapeutic option for TMZ-resistant GBM.

Bioactive Heterocyclic Compounds as Potential Therapeutics in the Treatment of Gliomas: A Review

Cancer is one of the most alarming diseases, with an estimation of 9.6 million deaths in 2018. Glioma occurs in glial cells surrounding nerve cells. The majority of the patients with gliomas have a terminal prognosis, and the ailment has significant sway on patients and their families, be it physical, psychological, or economic wellbeing. As Glioma exhibits, both intra and inter tumour heterogeneity with multidrug resistance and current therapies are ineffective. So the development of safer anti gliomas agents is the need of hour. Bioactive heterocyclic compounds, eithernatural or synthetic,are of potential interest since they have been active against different targets with a wide range of biological activities, including anticancer activities. In addition, they can cross the biological barriers and thus interfere with various signalling pathways to induce cancer cell death. All these advantages make bioactive natural compounds prospective candidates in the management of glioma. In this review, we assessed various bioactive heterocyclic compounds, such as jaceosidin, hispudlin, luteolin, silibinin, cannabidiol, tetrahydrocannabinol, didemnin B, thymoquinone, paclitaxel, doxorubicin, and cucurbitacins for their potential anti-glioma activity. Also, different kinds of chemical reactions to obtain various heterocyclic derivatives, e.g. indole, indazole, benzimidazole, benzoquinone, quinoline, quinazoline, pyrimidine, and triazine, are listed.

Design, Synthesis, and Biological Evaluation of a Novel Photocaged PI3K Inhibitor toward Precise Cancer Treatment

Aberrant activation of the PI3K pathway has been intensively targeted for cancer therapeutics for decades, leading to more than 40 PI3K inhibitors advanced into clinical trials. However, it is increasingly noticed that PI3K inhibitors often showed limited efficacy as well as a number of serious on-target adverse effects during the clinical development. In this work, we designed and synthesized a novel photocaged PI3K inhibitor 1, which could be readily activated by UV irradiation to release a highly potent PI3K inhibitor 2. Upon UV irradiation, the photocaged inhibitor 1 demonstrated remarkably enhanced antiproliferative activity against multiple cancer cell lines and significant efficacy in the patient-derived tumor organoid model. Furthermore, 1 also showed favorable anticancer activity in an in vivo zebrafish xenograft model. Taken together, the photocaged PI3K inhibitor 1 represents a promising avenue for novel therapeutics toward precise cancer treatment.

Discovery of new thieno[2,3-d]pyrimidine and thiazolo[5,4-d]pyrimidine derivatives as orally active phosphoinositide 3-kinase inhibitors

As abnormal PI3K signaling is a feature of many types of cancer, the development of orally active PI3K inhibitors is of great significance for targeted cancer therapy. Through integrating strategies of reducing aromatic character/increasing the fraction of sp3 carbons together with scaffold hopping, we designed and synthesized two new series of thieno[2,3-d]pyrimidine and thiazolo[5,4-d]pyrimidine derivatives for use as PI3K inhibitors. Our structure-activity relationship studies led to the identification of thieno[2,3-d]pyrimidine 6a and thiazolo[5,4-d]pyrimidine 7a, which exhibited remarkable nanomolar PI3K potency, good antiproliferative activity, favorable pharmacokinetic properties and significant in vivo anti-cancer efficacy. Notably, thiazolo[5,4-d]pyrimidine 7a had better anti-cancer activity than thieno[2,3-d]pyrimidine 6a and is worthy of further pre-clinical evaluation for its use in cancer treatment.

Discovery of novel quinazoline derivatives as potent PI3Kδ inhibitors with high selectivity

Inhibition of PI3Kδ has been proved to be an efficacious strategy for the treatment of hematological malignancies where the PI3K/Akt signaling pathway is hyperactive. Herein, a series of quinazoline derivatives bearing acrylamide fragment were prepared using skeleton-deconstruction strategy. The preliminary bioactivity evaluation resulted in the discovery of lead compound 15c. Compound 15c exhibited excellent enzyme activity against PI3Kδ (IC₅₀ = 27.5 nM) compared with BEZ235 as well as the significant anti-proliferation activities. With the high selectivity over other PI3K isoforms and potent effects on PI3K/Akt pathway, 15c can be identified as a promising PI3Kδ inhibitor worthy of further profiling.

Multitarget Inhibition of Histone Deacetylase (HDAC) and Phosphatidylinositol-3-kinase (PI3K): Current and Future Prospects

The discovery of histone deacetylase (HDAC) inhibitors is a hot topic in the medicinal chemistry community regarding cancer research. This is related primarily to two factors: success in the clinic, e. g., the four FDA-approved HDAC inhibitors, and strong versatility to combine their pharmacophoric features to design new hybrid compounds with multitarget profiles. Thus, the selection of adequate pharmacophores to combine, i. e., combining targets that can result in a synergistic effect, is desirable, as it increases the probability of discovering a new useful therapeutic strategy. In this work, we highlight the design of multitarget HDAC/PI3K inhibitors. Although this approach is still in its early stages, many significant works have described the design and pharmacological evaluation of this new promising class of multitarget inhibitors, where compound CUDC-907, which is already in clinical trials, stands out. Therefore, the question emerges of whether there still space for the design and evaluation of new multitarget HDAC/PI3K inhibitors. When considering the selectivity profile of the described multitarget compounds, the answer appears to be in the affirmative, especially since the first examples of compounds with a certain selectivity profile only recently appeared in 2020.

Identification of Novel Thiazolo[5,4-b]Pyridine Derivatives as Potent Phosphoinositide 3-Kinase Inhibitors

A series of novel 2-pyridyl, 4-morpholinyl substituted thiazolo[5,4-b]pyridine analogues have been designed and synthesized in this paper. These thiazolo[5,4-b]pyridines were efficiently prepared in seven steps from commercially available substances in moderate to good yields. All of these N-heterocyclic compounds were characterized by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) analysis and tested for phosphoinositide 3-kinase (PI3K) enzymatic assay. The results indicated that these N-heterocyclic compounds showed potent PI3K inhibitory activity, and the IC₅₀ of a representative compound (19a) could reach to 3.6 nm. The structure−activity relationships (SAR) study showed that sulfonamide functionality was important for PI3Kα inhibitory activity, and 2-chloro-4-florophenyl sulfonamide (19b), or 5-chlorothiophene-2-sulfonamide (19c) showed potent inhibitory activity with a nanomolar IC₅₀ value. The pyridyl attached to thiazolo[5,4-b]pyridine was another key structural unit for PI3Kα inhibitory potency, and replacement by phenyl lead to a significant decrease in activity. Enzymatic Inhibition results showed that compound 19a inhibited PI3Kα, PI3Kγ, or PI3Kδ with a nanomolar IC₅₀ value, but its inhibitory activity on PI3Kβ was approximately 10-fold reduced. Further docking analysis revealed that the N-heterocyclic core of compound 19a was directly involved in the binding to the kinase through the key hydrogen bonds interaction.

Dual inhibitors of histone deacetylases and other cancer-related targets: A pharmacological perspective

Epigenetic enzymes histone deacetylases (HDACs) are clinically validated anticancer drug targets which have been studied intensively in the past few decades. Although several drugs have been approved in this field, they are still limited to a subset of hematological malignancies (in particular T-cell lymphomas), with therapeutic potential not fully realized and the drug-resistance occurred after a certain period of use. To maximize the therapeutic potential of these classes of anticancer drugs, and to extend their application to solid tumors, numerous combination therapies containing an HDACi and an anticancer agent from other mechanisms are currently ongoing in clinical trials. Recently, dual targeting strategy comprising the HDACs component has emerged as an alternative approach for combination therapies. In this perspective, we intend to gather all HDACs-containing dual inhibitors related to cancer therapy published in literature since 2015, classify them into five categories based on targets' biological functions, and discuss the rationale why dual acting agents should work better than combinatorial therapies using two separate drugs. The article discusses the pharmacological aspects of these dual inhibitors, including in vitro biological activities, pharmacokinetic studies, in vivo efficacy studies, as well as available clinical trials. The review of the current status and advances should provide better analysis for future opportunities and challenges of this field.

Recent advances in the discovery of small molecules targeting glioblastoma

Glioblastoma (GBM) is one of the most common central nervous system cancers. It is characterized as a fast-growing tumor that arises from multiple cell types with neural stem-cell-like properties. Additionally, GBM tumors are highly invasive, which is attributed to the presence of glioblastoma stem cells that makes surgery ineffective in most cases. Currently, temozolomide is the unique chemotherapy option approved by the U.S. Food and Drug Administration for GBM treatment. This review analyzes the emergence and development of new synthetic small molecules discovered as promising anti-glioblastoma agents. A number of compounds were described herein and grouped according to the main chemical class used in the drug discovery process. Importantly, we focused only on synthetic compounds published in the last 10 years, thus excluding natural products. Furthermore, we included in this review only those most biologically active compounds with proven in vitro and/or in vivo efficacy.

A New Approach for Drug Target and Bioactivity Prediction: The Multifingerprint Similarity Search Algorithm (MuSSeL)

We present MuSSeL, a multifingerprint similarity search algorithm, able to predict putative drug targets for a given query small molecule as well as to return a quantitative assessment of its bioactivity in terms of K_i or IC₅₀ values. Predictions are automatically made exploiting a large collection of high quality experimental bioactivity data available from ChEMBL (version 22.1) combining, in a consensus-like approach, predictions resulting from a similarity search performed using 13 different fingerprint definitions. Importantly, the herein proposed algorithm is also effective in detecting and handling activity cliffs. A calibration set including small molecules present in the last updated version of ChEMBL (version 23) was employed to properly tune the algorithm parameters. Three randomly built external sets were instead challenged for model performances. The potential use of MuSSeL was also challenged by a prospective exercise for the prediction of five bioactive compounds taken from articles published in the Journal of Medicinal Chemistry just few months ago. The paper emphasizes the importance of implementing multifingerprint consensus strategies to increase the confidence in prediction of similarity search algorithms and provides a fast and easy-to-run tool for drug target and bioactivity prediction.