Etoposide: four decades of development of a topoisomerase II inhibitor

Organo NHC catalyzed aqueous synthesis of 4β-isoxazole-podophyllotoxins: in vitro anticancer, caspase activation, tubulin polymerization inhibition and molecular docking studies

We present, for the first time, the organo-N-heterocyclic carbene (NHC) catalyzed 1,3-dipolar cycloaddition of 4β-O-propargyl podophyllotoxin (1) with in situ aromatic nitrile oxides to afford regioselective 4β-isoxazolepodophyllotoxin hybrids (6a-n) in benign aqueous-organic media. Preliminary anticancer activity results showed that compound 6e displayed superior activity against MCF-7, HeLa and MIA PaCa2 human cell lines compared with podophyllotoxin. Compounds 6j and 6n showed greater activity against the MCF-7 cell line than the positive control. Caspase activation studies revealed that compound 6e at 20 μg ml-1 concentration had greater caspase 3/7 activation in MCF-7 and MIAPaCa2 cells than podophyllotoxin. Furthermore, in vitro tubulin polymerization inhibition studies revealed that compound 6e showed comparable activity with podophyllotoxin. Finally, in silico molecular docking studies of compounds 6e, 6j, 6n and podophyllotoxin on α,β-tubulin (pdb id 1SA0) revealed that compound 6n showed excellent binding energies and inhibition constants compared with podophyllotoxin.

WRN inhibition leads to its chromatin-associated degradation via the PIAS4-RNF4-p97/VCP axis

Synthetic lethality provides an attractive strategy for developing targeted cancer therapies. For example, cancer cells with high levels of microsatellite instability (MSI-H) are dependent on the Werner (WRN) helicase for survival. However, the mechanisms that regulate WRN spatiotemporal dynamics remain poorly understood. Here, we used single-molecule tracking (SMT) in combination with a WRN inhibitor to examine WRN dynamics within the nuclei of living cancer cells. WRN inhibition traps the helicase on chromatin, requiring p97/VCP for extraction and proteasomal degradation in a MSI-H dependent manner. Using a phenotypic screen, we identify the PIAS4-RNF4 axis as the pathway responsible for WRN degradation. Finally, we show that co-inhibition of WRN and SUMOylation has an additive toxic effect in MSI-H cells and confirm the in vivo activity of WRN inhibition using an MSI-H mouse xenograft model. This work elucidates a regulatory mechanism for WRN that may facilitate identification of new therapeutic modalities, and highlights the use of SMT as a tool for drug discovery and mechanism-of-action studies.

Endophytic fungi: A future prospect for breast cancer therapeutics and drug development

Globally, breast cancer is a primary contributor to cancer-related fatalities and illnesses among women. Consequently, there is a pressing need for safe and effective treatments for breast cancer. Bioactive compounds from endophytic fungi that live in symbiosis with medicinal plants have garnered significant interest in pharmaceutical research due to their extensive chemical composition and prospective medicinal attributes. This review underscores the potentiality of fungal endophytes as a promising resource for the development of innovative anticancer agents specifically tailored for breast cancer therapy. The diversity of endophytic fungi residing in medicinal plants, success stories of key endophytic bioactive metabolites tested against breast cancer and the current progress with regards to in vivo studies and clinical trials on endophytic fungal metabolites in breast cancer research forms the underlying theme of this article. A thorough compilation of putative anticancer compounds sourced from endophytic fungi that have demonstrated therapeutic potential against breast cancer, spanning the period from 1990 to 2022, has been presented. This review article also outlines the latest trends in endophyte-based drug discovery, including the use of artificial intelligence, machine learning, multi-omics approaches, and high-throughput strategies. The challenges and future prospects associated with fungal endophytes as substitutive sources for developing anticancer drugs targeting breast cancer are also being highlighted.

Topoisomerase Inhibitors and PIM1 Kinase Inhibitors Improve Gene Editing Efficiency Mediated by CRISPR-Cas9 and Homology-Directed Repair

The CRISPR-Cas9 system has emerged as the most prevalent gene editing technology due to its simplicity, high efficiency, and low cost. However, the homology-directed repair (HDR)-mediated gene knock-in in this system suffers from low efficiency, which limits its application in animal model preparation, gene therapy, and agricultural genetic improvement. Here, we report the design and optimization of a simple and efficient reporter-based assay to visualize and quantify HDR efficiency. Through random screening of a small molecule compound library, two groups of compounds, including the topoisomerase inhibitors and PIM1 kinase inhibitors, have been identified to promote HDR. Two representative compounds, etoposide and quercetagetin, also significantly enhance the efficiency of CRISPR-Cas9 and HDR-mediated gene knock-in in mouse embryos. Our study not only provides an assay to screen compounds that may facilitate HDR but also identifies useful tool compounds to facilitate the construction of genetically modified animal models with the CRISPR-Cas9 system.

Maximizing ovarian function and fertility following chemotherapy in premenopausal patients: Is there a role for ovarian suppression?

As more premenopausal patients undergo fertility preserving cancer treatments, there is an increased need for fertility counseling and ovarian sparing strategies. Many patients receive gonadotoxic chemotherapeutic agents which can put them at risk of primary ovarian insufficiency or profoundly diminished ovarian reserve. Traditionally, estradiol and follicle stimulating hormone (FSH) values have been used to evaluate ovarian function but more recently, reproductive endocrinologists have been proponents of anti-mullerian hormone (AMH) as a validated measure of ovarian potential. While the gold standard for fertility preservation remains oocyte cryopreservation, data suggest there may be additional interventions that can mitigate the gonadotoxic effects of chemotherapeutic agents. The main objectives of this focused review were to quantify the risk of primary ovarian failure associated with the most common chemotherapies used in treatment of gynecologic cancers and to evaluate and recommend potential interventions to mitigate toxic effects on ovarian function. Chemotherapeutic agents can cause direct loss of oocytes and primordial follicles as well as stromal and vascular atrophy and the extent is dependent upon mechanism of action and age of the patient. The risk of ovarian failure is the highest with alkylating agents (42.2 %), anthracyclines (<10-34 % in patients under 40 years versus 98 % in patients aged 40-49), taxanes (57.1 %) and platinum agents (50 %). Multiple trials demonstrate that gonadotropin releasing hormone (GnRH) agonists, when administered concurrently with chemotherapy, may have protective effects, with more patients experiencing resumption of a regular menstruation pattern and recovering ovarian function more quickly post-treatment. Premenopausal patients receiving chemotherapy for the treatment of gynecologic cancers should receive adequate counseling on the potential adverse effects on their fertility. Although oocyte cryopreservation remains the gold standard for fertility preservation, there is some evidence to suggest that GNRH agonists could help maintain and preserve ovarian function and should be considered.

The Role of Insulin-like Growth Factor Binding Protein (IGFBP)-2 in DNA Repair and Chemoresistance in Breast Cancer Cells

The role if insulin-like growth factor binding protein-2 (IGFBP-2) in mediating chemoresistance in breast cancer cells has been demonstrated, but the mechanism of action is unclear. This study aimed to further investigate the role of IGFBP-2 in the DNA damage response induced by etoposide in MCF-7, T47D (ER+ve), and MDA-MB-231 (ER-ve) breast cancer cell lines. In the presence or absence of etoposide, IGFBP-2 was silenced using siRNA in the ER-positive cell lines, or exogenous IGFBP-2 was added to the ER-negative MDA-MB-231 cells. Cell number and death were assessed using trypan blue dye exclusion assay, changes in abundance of proteins were monitored using Western blotting of whole cell lysates, and localization and abundance were determined using immunofluorescence and cell fractionation. Results from ER-positive cell lines demonstrated that upon exposure to etoposide, loss of IGFBP-2 enhanced cell death, and this was associated with a reduction in P-DNA-PKcs and an increase in γH2AX. Conversely, with ER-negative cells, the addition of IGFBP-2 in the presence of etoposide resulted in cell survival, an increase in P-DNA-PKcs, and a reduction in γH2AX. In summary, IGFBP-2 is a survival factor for breast cancer cells that is associated with enhancement of the DNA repair mechanism.

Autophagy suppression in DNA damaged cells occurs through a newly identified p53-proteasome-LC3 axis

Macroautophagy is thought to have a critical role in shaping and refining cellular proteostasis in eukaryotic cells recovering from DNA damage. Here, we report a mechanism by which autophagy is suppressed in cells exposed to bacterial toxin-, chemical-, or radiation-mediated sources of genotoxicity. Autophagy suppression is directly linked to cellular responses to DNA damage, and specifically the stabilization of the tumor suppressor p53, which is both required and sufficient for regulating the ubiquitination and proteasome-dependent reduction in cellular pools of microtubule-associated protein 1 light chain 3 (LC3A/B), a key precursor of autophagosome biogenesis and maturation, in both epithelial cells and an ex vivo organoid model. Our data indicate that suppression of autophagy, through a newly identified p53-proteasome-LC3 axis, is a conserved cellular response to multiple sources of genotoxicity. Such a mechanism could potentially be important for realigning proteostasis in cells undergoing DNA damage repair.

Combination Chemotherapy Optimization with Discrete Dosing

Chemotherapy drug administration is a complex problem that often requires expensive clinical trials to evaluate potential regimens; one way to alleviate this burden and better inform future trials is to build reliable models for drug administration. This paper presents a mixed-integer program for combination chemotherapy (utilization of multiple drugs) optimization that incorporates various important operational constraints and, besides dose and concentration limits, controls treatment toxicity based on its effect on the count of white blood cells. To address the uncertainty of tumor heterogeneity, we also propose chance constraints that guarantee reaching an operable tumor size with a high probability in a neoadjuvant setting. We present analytical results pertinent to the accuracy of the model in representing biological processes of chemotherapy and establish its potential for clinical applications through a numerical study of breast cancer.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma

The DNAJ-PKAc fusion kinase is a defining feature of fibrolamellar carcinoma (FLC). FLC tumors are notoriously resistant to standard chemotherapies, with aberrant kinase activity assumed to be a contributing factor. By combining proximity proteomics, biochemical analyses, and live-cell photoactivation microscopy, we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates, including proteins involved in translation and the anti-apoptotic factor Bcl-2-associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Tissue samples from patients with FLC exhibit increased levels of BAG2 in primary and metastatic tumors. Furthermore, drug studies implicate the DNAJ-PKAc/Hsp70/BAG2 axis in potentiating chemotherapeutic resistance. We find that the Bcl-2 inhibitor navitoclax enhances sensitivity to etoposide-induced apoptosis in cells expressing DNAJ-PKAc. Thus, our work indicates BAG2 as a marker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

YTHDF2 promotes DNA damage repair by positively regulating the histone methyltransferase SETDB1 in spermatogonia†

Genomic integrity is critical for sexual reproduction, ensuring correct transmission of parental genetic information to the descendant. To preserve genomic integrity, germ cells have evolved multiple DNA repair mechanisms, together termed as DNA damage response. The RNA N6-methyladenosine is the most abundant mRNA modification in eukaryotic cells, which plays important roles in DNA damage response, and YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) is a well-acknowledged N6-methyladenosine reader protein regulating the mRNA decay and stress response. Despite this, the correlation between YTHDF2 and DNA damage response in germ cells, if any, remains enigmatic. Here, by employing a Ythdf2-conditional knockout mouse model as well as a Ythdf2-null GC-1 mouse spermatogonial cell line, we explored the role and the underlying mechanism for YTHDF2 in spermatogonial DNA damage response. We identified that, despite no evident testicular morphological abnormalities under the normal circumstance, conditional mutation of Ythdf2 in adult male mice sensitized germ cells, including spermatogonia, to etoposide-induced DNA damage. Consistently, Ythdf2-KO GC-1 cells displayed increased sensitivity and apoptosis in response to DNA damage, accompanied by the decreased SET domain bifurcated 1 (SETDB1, a histone methyltransferase) and H3K9me3 levels. The Setdb1 knockdown in GC-1 cells generated a similar phenotype, but its overexpression in Ythdf2-null GC-1 cells alleviated the sensitivity and apoptosis in response to DNA damage. Taken together, these results demonstrate that the N6-methyladenosine reader YTHDF2 promotes DNA damage repair by positively regulating the histone methyltransferase SETDB1 in spermatogonia, which provides novel insights into the mechanisms underlying spermatogonial genome integrity maintenance and therefore contributes to safe reproduction.

Copper-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine based triazole-linked glycohybrids: mechanistic insights and bio-applications

Hybrid molecules maintain their stronghold in the drug market, with over 60% of drug candidates in pharmaceutical industries. The substantial expenses for developing and producing biologically privileged drugs are expected to create opportunities for producing hybrid molecule-based drugs. Therefore, we have developed a simple and efficient copper-catalyzed approach for synthesizing a wide range of triazole-linked glycohybrids derived from pyrazolo[1,5-a]pyrimidines. Employing a microwave-assisted copper-catalyzed approach, we developed a concise route using various 7-O-propargylated pyrazolo[1,5-a]pyrimidines and 1-azidoglycosides. This strategy afforded a series of twenty-seven glycohybrids up to 98% yield with diverse stereochemistry. All were achieved within a remarkably shortened time frame. Our investigation extends to evaluating the anticancer potential of these synthesized triazole-linked pyrazolo[1,5-a] pyrimidine-based glycohybrids. In-vitro assays against MCF-7, MDA-MB231, and MDA-MB453 cell lines reveal intriguing findings. (2R,3S,4S,5R,6R)-2-(acetoxymethyl)-6-(4-(((5-(4-chlorophenyl)pyrazolo[1,5-a]pyrimidin-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate emerges as a standout with better anticancer activity against MDA-MB231 cells (IC50 = 29.1 µM), while (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(4-(((5-(4-chlorophenyl)pyrazolo[1,5-a]pyrimidin-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate demonstrates the best inhibitory effects against MCF-7 cells (IC50 = 15.3 µM) in all derived compounds. These results align with our docking analysis and structure-activity relationship (SAR) investigations, further validating the in-vitro outcomes. This work not only underscores the synthetic utility of our devised protocol but also highlights the promising potential of these glycohybrids as candidates for further anticancer therapeutic exploration.

Synthesis of triazole bridged N-glycosides of pyrazolo[1,5-a]pyrimidinones as anticancer agents and their in silico docking studies

In the pursuit of novel therapeutic agents, we present a comprehensive study on the design, synthesis, and evaluation of a diverse library of triazole bridged N-glycosides of pyrazolo[1,5-a]pyrimidinones, employing a microwave-assisted synthetic approach via 'click chemistry'. This methodology offers efficient and accelerated access to the glycohybrids, showcasing improved reaction conditions that yield high-quality products. In this research endeavor, we have successfully synthesized a series of twenty-seven triazole bridged N-glycosides of pyrazolo[1,5-a]pyrimidinones. Our investigation extends beyond synthetic endeavors to explore the potential therapeutic relevance of these compounds. We subjected them to rigorous in vitro screening against prominent breast cancer cell lines MCF-7, MDA-MB231, and MDA-MB453. Among the library of compounds synthesized, (2S,3S,4R,5S,6S)-2-(acetoxymethyl)-6-(4-((5-(4-methoxyphenyl)-7-oxopyrazolo[1,5-a]pyrimidin-1(7H)-yl)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate emerged as a potent compound, exhibiting remarkable anti-cancer activity with an IC50 value of 27.66 μM against the MDA-MB231 cell line. Additionally, (2S,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(4-((7-oxo-5-(4-(trifluoromethyl)phenyl)pyrazolo[1,5-a]pyrimidin-1(7H)-yl)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate displayed notable inhibitory potential against the MCF-7 cell line, with an IC50 value of 4.93 μM. Furthermore, in silico docking analysis was performed to validate our experimental findings. These findings underscore the promise of our triazole bridged N-glycosides of pyrazolo[1,5-a]pyrimidinones as potential anti-cancer agents. This research not only enriches the field of glycohybrid synthesis but also contributes valuable insights into the development of novel anti-cancer therapeutics.

Phytotherapeutics in Cancer: From Potential Drug Candidates to Clinical Translation

Annually, a significant number of individuals succumb to cancer, an anomalous cellular condition characterized by uncontrolled cellular proliferation and the emergence of highly perilous tumors. Identifying underlying molecular mechanism(s) driving disease progression has led to various inventive therapeutic approaches, many of which are presently under pre-clinical and/or clinical trials. Over the recent years, numerous alternative strategies for addressing cancer have also been proposed and put into practice. This article delineates the modern therapeutic drugs employed in cancer treatment and their associated toxicity. Due to inherent drug toxicity associated with most modern treatments, demand rises for alternative therapies and phytochemicals with minimal side effects and proven efficacy against cancer. Analogs of taxol, Vinca alkaloids like vincristine and vinblastine, and podophyllotoxin represent a few illustrative examples in this context. The phytochemicals often work by modifying the activity of molecular pathways that are thought to be involved in the onset and progression of cancer. The principal objective of this study is to provide an overview of our current understanding regarding the pharmacologic effects and molecular targets of the active compounds found in natural products for cancer treatment and collate information about the recent advancements in this realm. The authors' interest in advancing the field of phytochemical research stems from both the potential of these compounds for use as drugs as well as their scientific validity. Accordingly, the significance of herbal formulations is underscored, shedding light on anticancer phytochemicals that are sought after at both pre-clinical and clinical levels, with discussion on the opportunities and challenges in pre-clinical and clinical cancer studies.

The ERF transcription factor LTF1 activates DIR1 to control stereoselective synthesis of antiviral lignans and stress defense in Isatis indigotica roots

Lignans are a powerful weapon for plants to resist stresses and have diverse bioactive functions to protect human health. Elucidating the mechanisms of stereoselective biosynthesis and response to stresses of lignans is important for the guidance of plant improvement. Here, we identified the complete pathway to stereoselectively synthesize antiviral (-)-lariciresinol glucosides in Isatis indigotica roots, which consists of three-step sequential stereoselective enzymes DIR1/2, PLR, and UGT71B2. DIR1 was further identified as the key gene in respoJanuary 2024nse to stresses and was able to trigger stress defenses by mediating the elevation in lignan content. Mechanistically, the phytohormone-responsive ERF transcription factor LTF1 colocalized with DIR1 in the cell periphery of the vascular regions in mature roots and helped resist biotic and abiotic stresses by directly regulating the expression of DIR1. These systematic results suggest that DIR1 as the first common step of the lignan pathway cooperates with PLR and UGT71B2 to stereoselectively synthesize (-)-lariciresinol derived antiviral lignans in I. indigotica roots and is also a part of the LTF1-mediated regulatory network to resist stresses. In conclusion, the LTF1-DIR1 module is an ideal engineering target to improve plant Defenses while increasing the content of valuable lignans in plants.

Anthriscus sylvestris Deoxypodophyllotoxin Synthase Involved in the Podophyllotoxin Biosynthesis

Tetrahydrofuran ring formation from dibenzylbutyrolactone lignans is a key step in the biosynthesis of aryltetralin lignans including deoxypodophyllotoxin and podophyllotoxin. Previously, Fe(II)- and 2-oxoglutarate-dependent dioxygenase (2-ODD) from Podophyllum hexandrum (Himalayan mayapple, Berberidaceae) was found to catalyze the cyclization of a dibenzylbutyrolactone lignan, yatein, to give deoxypodophyllotoxin and designated as deoxypodophyllotoxin synthase (DPS). Recently, we reported that the biosynthesis of deoxypodophyllotoxin and podophyllotoxin evolved in a lineage-specific manner in phylogenetically unrelated plant species such as P. hexandrum and Anthriscus sylvestris (cow parsley, Apiaceae). Therefore, a comprehensive understanding of the characteristics of DPSs that catalyze the cyclization of yatein to deoxypodophyllotoxin in various plant species is important. However, for plant species other than P. hexandrum, the isolation of the DPS enzyme gene and the type of the enzyme, e.g. whether it is 2-ODD or another type of enzyme such as cytochrome P-450, have not been reported. In this study, we report the identification and characterization of A. sylvestris DPS (AsDPS). Phylogenetic analysis showed that AsDPS belonged to the 2-ODD superfamily and shared moderate amino acid sequence identity (40.8%) with P. hexandrum deoxypodophyllotoxin synthase (PhDPS). Recombinant protein assay indicated that AsDPS and PhDPS differ in terms of the selectivity of substrate enantiomers. Protein modeling using AlphaFold2 and site-directed mutagenesis indicated that the Tyr305 residue of AsDPS probably contributes to substrate recognition. This study advances our understanding of the podophyllotoxin biosynthetic pathway in A. sylvestris and provides new insight into 2-ODD involved in plant secondary (specialized) metabolism.

Identification of Novel β-Tubulin Inhibitors Using a Combined In Silico/In Vitro Approach

Due to their potential as leads for various therapeutic applications, including as antimitotic and antiparasitic agents, the development of tubulin inhibitors offers promise for drug discovery. In this study, an in silico pharmacophore-based virtual screening approach targeting the colchicine binding site of β-tubulin was employed. Several structure- and ligand-based models for known tubulin inhibitors were generated. Compound databases were virtually screened against the models, and prioritized hits from the SPECS compound library were tested in an in vitro tubulin polymerization inhibition assay for their experimental validation. Out of the 41 SPECS compounds tested, 11 were active tubulin polymerization inhibitors, leading to a prospective true positive hit rate of 26.8%. Two novel inhibitors displayed IC50 values in the range of colchicine. The most potent of which was a novel acetamide-bridged benzodiazepine/benzimidazole derivative with an IC50 = 2.9 μM. The screening workflow led to the identification of diverse inhibitors active at the tubulin colchicine binding site. Thus, the pharmacophore models show promise as valuable tools for the discovery of compounds and as potential leads for the development of cancer therapeutic agents.

Ferrocene/ β-cyclodextrin based supramolecular nanogels as theranostic systems

A supramolecular redox responsive nanogel (NG) with the ability to sense cancer cells and loaded with a releasing therapeutic agent was synthesized using hostguest interactions between polyethylene glycol-grafted-β-cyclodextrin and ferrocene boronic acid. Cyclic voltammetry matched with other spectroscopy and microscopy methods provided strong indications regarding host-guest interactions and formation of the NG. Moreover, the biological properties of the NG were evaluated using fluorescence silencing, confocal laser scanning microscopy, and cell toxicity assays. Nanogel with spherical core-shell architecture and 100-200 nm sized nanoparticles showed high encapsulation efficiency for doxorubicin (DOX) and luminol (LU) as therapeutic and sensing agents. High therapeutic and sensing efficiencies were manifested by complete release of DOX and dramatic quenching of LU fluorescence triggered by 0.05 mM H2O2 (as an ROS component). The NGs showed high ROS sensitivity. Taking advantage of a high loading capacity, redox sensitivity, and biocompatibility, the NGs can be used as strong theranostic systems in inflammation-associated diseases.

Assessment of Drug-Induced Liver Injury through Cell Morphology and Gene Expression Analysis

Drug-induced liver injury (DILI) is a significant concern in drug development, often leading to drug withdrawal. Although many studies aim to identify biomarkers and gene/pathway signatures related to liver toxicity and aim to predict DILI compounds, this remains a challenge in drug discovery. With a strong development of high-content screening/imaging (HCS/HCI) for phenotypic screening, we explored the morphological cell perturbations induced by DILI compounds. In the first step, cell morphological signatures were associated with two datasets of DILI chemicals (DILIRank and eTox). The mechanisms of action were then analyzed for chemicals having transcriptomics data and sharing similar morphological perturbations. Signaling pathways associated with liver toxicity (cell cycle, cell growth, apoptosis, ...) were then captured, and a hypothetical relation between cell morphological perturbations and gene deregulation was illustrated within our analysis. Finally, using the cell morphological signatures, machine learning approaches were developed to predict chemicals with a potential risk of DILI. Some models showed relevant performance with validation set balanced accuracies between 0.645 and 0.739. Overall, our findings demonstrate the utility of combining HCI with transcriptomics data to identify the morphological and gene expression signatures related to DILI chemicals. Moreover, our protocol could be extended to other toxicity end points, offering a promising avenue for comprehensive toxicity assessment in drug discovery.

A metabolic map of the DNA damage response identifies PRDX1 in the control of nuclear ROS scavenging and aspartate availability

While cellular metabolism impacts the DNA damage response, a systematic understanding of the metabolic requirements that are crucial for DNA damage repair has yet to be achieved. Here, we investigate the metabolic enzymes and processes that are essential for the resolution of DNA damage. By integrating functional genomics with chromatin proteomics and metabolomics, we provide a detailed description of the interplay between cellular metabolism and the DNA damage response. Further analysis identified that Peroxiredoxin 1, PRDX1, contributes to the DNA damage repair. During the DNA damage response, PRDX1 translocates to the nucleus where it reduces DNA damage-induced nuclear reactive oxygen species. Moreover, PRDX1 loss lowers aspartate availability, which is required for the DNA damage-induced upregulation of de novo nucleotide synthesis. In the absence of PRDX1, cells accumulate replication stress and DNA damage, leading to proliferation defects that are exacerbated in the presence of etoposide, thus revealing a role for PRDX1 as a DNA damage surveillance factor.

Mechanisms of Secondary Leukemia Development Caused by Treatment with DNA Topoisomerase Inhibitors

Leukemia is a blood cancer originating in the blood and bone marrow. Therapy-related leukemia is associated with prior chemotherapy. Although cancer therapy with DNA topoisomerase II inhibitors is one of the most effective cancer treatments, its side effects include development of secondary leukemia characterized by the chromosomal rearrangements affecting AML1 or MLL genes. Recurrent chromosomal translocations in the therapy-related leukemia differ from chromosomal rearrangements associated with other neoplasias. Here, we reviewed the factors that drive chromosomal translocations induced by cancer treatment with DNA topoisomerase II inhibitors, such as mobility of ends of double-strand DNA breaks formed before the translocation and gain of function of fusion proteins generated as a result of translocation.

Curing childhood cancer the "Natural" Way: Nature as the source of chemotherapy agents

For many centuries, products of natural origin from plants, marine, microbes and soil micro-organisms have been studied by numerous researchers across the world to yield many of the chemotherapeutic agents we use in this modern era. There has been a tremendous gain in knowledge from various screening and separating techniques which led to the discovery of biologically active small molecules from natural products. Preclinical studies testing the antitumor activities of these agents against tumor cell lines and xenograft animal models were the gateway to the clinical trials in humans leading to the approval of these agents that are in clinical use today. This review summarizes how various chemotherapeutic agents were discovered from products of natural origin, their preclinical development, and their indications in both pediatric and adult oncology. Many of these natural products have contributed to the very high cure rates of both pediatric leukemias and solid tumors.

Cancer chemotherapy and beyond: Current status, drug candidates, associated risks and progress in targeted therapeutics

Cancer is an abnormal state of cells where they undergo uncontrolled proliferation and produce aggressive malignancies that causes millions of deaths every year. With the new understanding of the molecular mechanism(s) of disease progression, our knowledge about the disease is snowballing, leading to the evolution of many new therapeutic regimes and their successive trials. In the past few decades, various combinations of therapies have been proposed and are presently employed in the treatment of diverse cancers. Targeted drug therapy, immunotherapy, and personalized medicines are now largely being employed, which were not common a few years back. The field of cancer discoveries and therapeutics are evolving fast as cancer type-specific biomarkers are progressively being identified and several types of cancers are nowadays undergoing systematic therapies, extending patients' disease-free survival thereafter. Although growing evidence shows that a systematic and targeted approach could be the future of cancer medicine, chemotherapy remains a largely opted therapeutic option despite its known side effects on the patient's physical and psychological health. Chemotherapeutic agents/pharmaceuticals served a great purpose over the past few decades and have remained the frontline choice for advanced-stage malignancies where surgery and/or radiation therapy cannot be prescribed due to specific reasons. The present report succinctly reviews the existing and contemporary advancements in chemotherapy and assesses the status of the enrolled drugs/pharmaceuticals; it also comprehensively discusses the emerging role of specific/targeted therapeutic strategies that are presently being employed to achieve better clinical success/survival rate in cancer patients.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma

The DNAJ-PKAc fusion kinase is a defining feature of the adolescent liver cancer fibrolamellar carcinoma (FLC). A single lesion on chromosome 19 generates this mutant kinase by creating a fused gene encoding the chaperonin binding domain of Hsp40 (DNAJ) in frame with the catalytic core of protein kinase A (PKAc). FLC tumors are notoriously resistant to standard chemotherapies. Aberrant kinase activity is assumed to be a contributing factor. Yet recruitment of binding partners, such as the chaperone Hsp70, implies that the scaffolding function of DNAJ- PKAc may also underlie pathogenesis. By combining proximity proteomics with biochemical analyses and photoactivation live-cell imaging we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates. One validated DNAJ-PKAc target is the Bcl-2 associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Immunoblot and immunohistochemical analyses of FLC patient samples correlate increased levels of BAG2 with advanced disease and metastatic recurrences. BAG2 is linked to Bcl-2, an anti-apoptotic factor that delays cell death. Pharmacological approaches tested if the DNAJ- PKAc/Hsp70/BAG2 axis contributes to chemotherapeutic resistance in AML12 DNAJ-PKAc hepatocyte cell lines using the DNA damaging agent etoposide and the Bcl-2 inhibitor navitoclax. Wildtype AML12 cells were susceptible to each drug alone and in combination. In contrast, AML12 DNAJ-PKAc cells were moderately affected by etoposide, resistant to navitoclax, but markedly susceptible to the drug combination. These studies implicate BAG2 as a biomarker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

Apatinib plus etoposide in pretreated patients with advanced triple-negative breast cancer: a phase II trial

BACKGROUND

Treatment options for pretreated triple-negative breast cancer (TNBC) are limited. This study aimed to evaluate the efficacy and safety of apatinib, an antiangiogenic agent, in combination of etoposide for pretreated patients with advanced TNBC.

METHODS

In this single-arm phase II trial, patients with advanced TNBC who failed to at least one line of chemotherapy were enrolled. Eligible patients received oral apatinib 500 mg on day 1 to 21, plus oral etoposide 50 mg on day 1 to 14 of a 3-week cycle until disease progression or intolerable toxicities. Etoposide was administered up to six cycles. The primary endpoint was progression-free survival (PFS).

RESULTS

From September 2018 to September 2021, 40 patients with advanced TNBC were enrolled. All patients received previous chemotherapy in the advanced setting, with the median previous lines of 2 (1-5). At the cut-off date on January 10, 2022, the median follow-up was 26.8 (1.6-52.0) months. The median PFS was 6.0 (95% confidence interval [CI]: 3.8-8.2) months, and the median overall survival was 24.5 (95%CI: 10.2-38.8) months. The objective response rate and disease control rate was 10.0% and 62.5%, respectively. The most common adverse events (AEs) were hypertension (65.0%), nausea (47.5%) and vomiting (42.5%). Four patients developed grade 3 AE, including two with hypertension and two with proteinuria.

CONCLUSIONS

Apatinib combined with oral etoposide was feasible in pretreated advanced TNBC, and was easy to administer.

CLINICAL TRIAL REGISTRATION

Chictr.org.cn, (registration number: ChiCTR1800018497, registration date: 20/09/2018).

DDRGK1 Enhances Osteosarcoma Chemoresistance via Inhibiting KEAP1-Mediated NRF2 Ubiquitination

Chemoresistance is the main obstacle in osteosarcoma (OS) treatment; however, the underlying mechanism remains unclear. In this study, it is discovered that DDRGK domain-containing protein 1 (DDRGK1) plays a fundamental role in chemoresistance induced in OS. Bioinformatic and tissue analyses indicate that higher expression of DDRGK1 correlates with advanced tumor stage and poor clinical prognosis of OS. Quantitative proteomic analyses suggest that DDRGK1 plays a critical role in mitochondrial oxidative phosphorylation. DDRGK1 knockout trigger the accumulation of reactive oxygen species (ROS) and attenuate the stability of nuclear factor erythroid-2-related factor 2 (NRF2), a major antioxidant response element. Furthermore, DDRGK1 inhibits ubiquitin-proteasome-mediated degradation of NRF2 via competitive binding to the Kelch-like ECH-associated protein 1 (KEAP1) protein, which recruits NRF2 to CULLIN(CUL3). DDRGK1 knockout attenuates NRF2 stability, contributing to ROS accumulation, which promotes apoptosis and enhanced chemosensitivity to doxorubicin (DOX) and etoposide in cancer cells. Indeed, DDRGK1 knockout significantly enhances osteosarcoma chemosensitivity to DOX in vivo. The combination of DDRGK1 knockdown and DOX treatment provides a promising new avenue for the effective treatment of OS.

Etoposide promotes DNA loop trapping and barrier formation by topoisomerase II

Etoposide is a broadly employed chemotherapeutic and eukaryotic topoisomerase II poison that stabilizes cleaved DNA intermediates to promote DNA breakage and cytotoxicity. How etoposide perturbs topoisomerase dynamics is not known. Here we investigated the action of etoposide on yeast topoisomerase II, human topoisomerase IIα and human topoisomerase IIβ using several sensitive single-molecule detection methods. Unexpectedly, we found that etoposide induces topoisomerase to trap DNA loops, compacting DNA and restructuring DNA topology. Loop trapping occurs after ATP hydrolysis but before strand ejection from the enzyme. Although etoposide decreases the innate stability of topoisomerase dimers, it increases the ability of the enzyme to act as a stable roadblock. Interestingly, the three topoisomerases show similar etoposide-mediated resistance to dimer separation and sliding along DNA but different abilities to compact DNA and chirally relax DNA supercoils. These data provide unique mechanistic insights into the functional consequences of etoposide on topoisomerase II dynamics.

Investigating the Functional Roles of Aldehyde Dehydrogenase 3A1 in Human Corneal Epithelial Cells

Aldehyde dehydrogenase 3A1 (ALDH3A1) oxidizes medium-chain aldehydes to their corresponding carboxylic acids. It is expressed at high rates in the human cornea, where it has been characterized as a multi-functional protein displaying various cytoprotective modes of action. Previous studies identified its association with the DNA damage response (DDR) pathway. Here, we utilized a stable transfected HCE-2 (human corneal epithelium) cell line expressing ALDH3A1, to investigate the molecular mechanisms underlying the cytoprotective role(s) of ALDH3A1. Our data revealed morphological differences among the ALDH3A1-expressing and the mock-transfected HCE-2 cells accompanied by differential expression of E-cadherin. Similarly, the ALDH3A1/HCE-2 cells demonstrated higher mobility, reduced proliferation, upregulation of ZEB1, and downregulation of CDK3, and p57. The expression of ALDH3A1 also affected cell cycle progression by inducing the sequestration of HCE-2 cells at the G2/M phase. Following 16 h cell treatments with either H₂O₂ or etoposide, a significantly lower percentage of ALDH3A1/HCE-2 cells were apoptotic compared to the respective treated mock/HCE-2 cells. Interestingly, the protective effect of ALDH3A1 expression under these oxidative and genotoxic conditions was accompanied by a reduced formation of γ-H2AX foci and higher levels of total and phospho (Ser15) p53. Finally, ALDH3A1 was found to be localized both in the cytoplasm and the nucleus of transfected HCE-2 cells. Its cellular compartmentalization was not affected by oxidant treatment, while the mechanism by which ALDH3A1 translocates to the nucleus remains unknown. In conclusion, ALDH3A1 protects cells from both apoptosis and DNA damage by interacting with key homeostatic mechanisms associated with cellular morphology, cell cycle, and DDR.

Organometallic Iridium Complexes with Glucose Based Phosphite Ligands

New organometallic iridium compounds with phosphorus modified glucose ligands containing isopropylidene protection group or bearing uracil, thymine, and 5-fluorouracil (3,5,6-bicyclophosphite-1,2-O-isopropylidene-α-d-glucofuranoside, 3,5,6-bicyclophosphite-1-β-D-glucofuranosyluracil, 3,5,6-bicyclophosphite-1-β-D-glucofuranosylthymine, 3,5,6-bicyclophosphite-1-β-D-glucofuranosyl-5-flurouracil) were prepared. The structure of the new complexes was confirmed by the spectroscopic technique (1H, 31P{1H} NMR) and mass spectrometry, and purity by elemental analysis. The molecular structure of the complex with the isopropylidene protection group was established by the X-ray analysis. The antiproliferative activity of the new iridium compounds was evaluated against several cancer cell lines of human origin, and all compounds showed low toxicity independent of the pyrimidine base nature, attached to the sugar unit.

Opioid induces increased DNA damage in prefrontal cortex and nucleus accumbens

Opioid use disorder (OUD) is a chronic disease characterized by compulsive opioid taking and seeking, affecting millions of people worldwide. The high relapse rate is one of the biggest challenges in treating opioid addiction. However, the cellular and molecular mechanisms underlying relapse to opioid seeking are still unclear. Recent studies have shown that DNA damage and repair processes are implicated in a broad spectrum of neurodegenerative diseases as well as in substance use disorders. In the present study, we hypothesized that DNA damage is related to relapse to heroin seeking. To test our hypothesis, we aim to examine the overall DNA damage level in prefrontal cortex (PFC) and nucleus accumbens (NAc) after heroin exposure, as well as whether manipulating DNA damage levels can alter heroin seeking. First, we observed increased DNA damage in postmortem PFC and NAc tissues from OUD individuals compared to healthy controls. Next, we found significantly increased levels of DNA damage in the dorsomedial PFC (dmPFC) and NAc from mice that underwent heroin self-administration. Moreover, increased accumulation of DNA damage persisted after prolonged abstinence in mouse dmPFC, but not in NAc. This persistent DNA damage was ameliorated by the treatment of reactive oxygen species (ROS) scavenger N-acetylcysteine, along with attenuated heroin-seeking behavior. Furthermore, intra-PFC infusions of topotecan and etoposide during abstinence, which trigger DNA single-strand breaks and double-strand breaks respectively, potentiated heroin-seeking behavior. These findings provide direct evidence that OUD is associated with the accumulation of DNA damage in the brain (especially in the PFC), which may lead to opioid relapse.

A cell state specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma

Glioma cells hijack developmental transcriptional programs to control cell state. During neural development, lineage trajectories rely on specialized metabolic pathways. However, the link between tumor cell state and metabolic programs is poorly understood in glioma. Here we uncover a glioma cell state-specific metabolic liability that can be leveraged therapeutically. To model cell state diversity, we generated genetically engineered murine gliomas, induced by deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling cellular fate. N1IC tumors harbored quiescent astrocyte-like transformed cell states while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. N1IC cells exhibit distinct metabolic alterations, with mitochondrial uncoupling and increased ROS production rendering them more sensitive to inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Importantly, treating patient-derived organotypic slices with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles.

Podophyllotoxin and its derivatives: Potential anticancer agents of natural origin in cancer chemotherapy

The use of plant secondary metabolites has gained considerable attention among clinicians in the prevention and treatment of cancer. A secondary metabolite isolated mainly from the roots and rhizomes of Podophyllum species (Berberidaceae) is aryltetralin lignan - podophyllotoxin (PTOX). The purpose of this review is to discuss the therapeutic properties of PTOX as an important anticancer compound of natural origin. The relevant information regarding the antitumor mechanisms of podophyllotoxin and its derivatives were collected and analyzed from scientific databases. The results of the analysis showed PTOX exhibits potent cytotoxic activity; however, it cannot be used in its pure form due to its toxicity and generation of many side effects. Therefore, it practically remains clinically unusable. Currently, high effort is focused on attempts to synthesize analogs of PTOX that have better properties for therapeutic use e.g. etoposide (VP-16), teniposide, etopophos. PTOX derivatives are used as anticancer drugs which are showing additional immunosuppressive, antiviral, antioxidant, hypolipemic, and anti-inflammatory effects. In this review, attention is paid to the high potential of the usefulness of in vitro cultures of P. peltatum which can be a valuable source of lignans, including PTOX. In conclusion, the preclinical pharmacological studies in vitro and in vivo confirm the anticancer and chemotherapeutic potential of PTOX and its derivatives. In the future, clinical studies on human subjects are needed to certify the antitumor effects and the anticancer mechanisms to be certified and analyzed in more detail and to validate the experimental pharmacological preclinical studies.

Short-Term Starvation Weakens the Efficacy of Cell Cycle Specific Chemotherapy Drugs through G1 Arrest

Short-term starvation (STS) during chemotherapy can block the nutrient supply to tumors and make tumor cells much more sensitive to chemotherapeutic drugs than normal cells. However, because of the diversity of starvation methods and the heterogeneity of tumors, this method's specific effects and mechanisms for chemotherapy are still poorly understood. In this study, we used HeLa cells as a model for short-term starvation and etoposide (ETO) combined treatment, and we also mimicked the short-term starvation effect by knocking down the glycolytic enzyme GAPDH to explore the exact molecular mechanism. In addition, our study demonstrated that short-term starvation protects cancer cells against the chemotherapeutic agent ETO by reducing DNA damage and apoptosis due to the STS-induced cell cycle G1 phase block and S phase reduction, thereby diminishing the effect of ETO. Furthermore, these results suggest that starvation therapy in combination with cell cycle-specific chemotherapeutic agents must be carefully considered.

A new host-targeted antiviral cyclolignan (SAU-22.107) for Dengue Virus infection in cell cultures. Potential action mechanisms based on cell imaging

Dengue virus (DENV) infection is the most arbovirosis in the world. However, medications have not been approved for its treatment. Drug discovery based on the host-targeted antiviral (HTA) constitutes a new promising strategy, considering their high genetic barrier to resistance and the low probability of selecting drug resistance strains. In this study, we have tested fifty-seven podophyllotoxin-related cyclolignans on DENV-2 infected cells and found the most promising compound was S.71. Using cellular and molecular biology experiments, we have discovered that the new lignan altered the distribution of microtubules, induced changes in cell morphology, and caused retraction of the rough endoplasmic reticulum. In addition, the compound alters the viral envelope protein and the double-stranded RNA, while there is a decrease in negative-strand RNA synthesis; especially when the compound was added between 6- and 12-hours post-infection. Altogether, S.71 decreases the viral yield through an HTA-related mechanism of action, possibly altering the DENV genome replication and/or polyprotein translation, through the alteration of microtubule distribution and endoplasmic reticulum deterioration. Finally, pharmacokinetic predictors show that S.71 falls within the standard ranges established for drugs.

Prospective Challenges for Patenting and Clinical Trials of Anticancer Compounds from Natural Products: Coherent Review

Cancer is a leading cause of morbidity and mortality worldwide. Each year, millions of people worldwide are diagnosed with cancer, and more than half of them die. Various conventional therapies for cancer, including chemotherapy and radiotherapy, have extreme side effects. Therefore, to minimize the global burden of lethal diseases like cancer, an effective and novel drug must be discovered. Its patent should be acquired to secure the novel medicament. The pharmacological potential of different natural products has made them popular in the healthcare and pharmaceutical industries. Various anticancer compounds are obtained from natural sources such as plants, microbes, and marine and terrestrial animals, including alkaloids, terpenoids, biophenols, enzymes, glycosides, etc. The term "natural products" is defined as the product of secondary or non-essential metabolic processes produced by living organisms (such as plants, invertebrates, and microorganisms). Although more precise definitions of NPs exist, they do not always meet consensus. Others define NPs as small molecules (excluding biomolecules) that emerge from the metabolic reaction. A handful of effective compounds are used currently from natural or analog moieties, and many more are in clinical studies. There is an excellent need for patenting molecules from natural products as the hit lead molecules are derived, isolated, and synthesized from natural products. However, these naturally occurring products may not be patentable under the law because they come from nature. This review highlights why natural products and compounds are hard to patent, under what patent law criteria we can patent these natural products and compounds, patent procedural guideline sources and why researchers prefer publication rather than a patent. Here, various patent scenarios of natural products and compounds for cancer have been given.

Chemistry and Biological Activities of Naturally Occurring and Structurally Modified Podophyllotoxins

Plants containing podophyllotoxin and its analogues have been used as folk medicines for centuries. The characteristic chemical structures and strong biological activities of this class of compounds attracted attention worldwide. Currently, more than ninety natural podophyllotoxins were isolated, and structure modifications of these molecules were performed to afford a variety of derivatives, which offered optimized anti-tumor activity. This review summarized up to date reports on natural occurring podophyllotoxins and their sources, structural modification and biological activities. Special attention was paid to both structural modification and optimized antitumor activity. It was noteworthy that etoposide, a derivative of podophyllotoxin, could prevent cytokine storm caused by the recent SARS-CoV-2 viral infection.

Bioinspired Nanocomplexes Comprising Phenolic Acid Derivative and Human Serum Albumin for Cancer Therapy

Inspired by the natural phenomenon of phenolic-protein interactions, we translate this "naturally evolved interaction" to a "phenolic acid derivative based albumin bound" technology, through the synthesis of phenolic acid derivatives comprising a therapeutic cargo linked to a phenolic motif. Phenolic acid derivatives can bind to albumin and form nanocomplexes after microfluidic mixing. This strategy has been successfully applied to different types of anticancer drugs, including taxanes, anthraquinones, etoposides, and terpenoids. Paclitaxel was selected as a model drug for an in-depth study. Three novel paclitaxel-phenolic acid conjugates have been synthesized. Molecular dynamics simulations provide insights into the self-assembled mechanisms of phenolic-protein nanocomplexes. The nanocomplexes show improved pharmacokinetics, elevated tolerability, decreased neurotoxicity, and enhanced anticancer efficacies in multiple murine xenograft models of breast cancer, in comparison with two clinically approved formulations, Taxol (polyoxyethylated castor oil-formulated paclitaxel) and Abraxane (nab-paclitaxel). Such a robust system provides a broadly applicable platform for the development of albumin-based nanomedicines and has great potential for clinical translation.

Dual-Drug Nanosystem: Etoposide Prodrug and Cisplatin Coloaded Nanostructured Lipid Carriers for Lung Cancer Therapy

Purpose

Cisplatin (CDDP) and etoposide (Etp) are recommended first-line therapy for lung cancer. Nanostructured lipid carriers (NLCs) are engineered to deliver drugs for lung cancer treatment. In the present study, NLCs were applied to coload an Etp prodrug (EtpP) and CDDP.

Methods

The Etp prodrug was synthesized by linking the phenolic hydroxyl group of Etp with polyethylene glycol (PEG). EtpP and CDDP coencapsulated NLCs (EtpP-CDDP NLCs) were prepared using film ultrasound. Cytotoxicity of drugs and drug-containing NLCs was assessed by evaluating cell viability using MTT assays. In vivo antitumor efficiency of EtpP-CDDP NLCs was evaluated on lung cancer-bearing xenografts.

Results

EtpP-CDDP NLCs showed a uniformly spherical morphology with a size of 176.8±4.9 nm and -potential of -31.9±3.2 mV. Cellular uptake efficiency of EtpP-CDDP NLCs was 57.4%±3.9% on A549/DDP cells. EtpP-CDDP NLCs exhibited more sustained plasma retention, the highest drug distribution in tumors, and the highest tumor-inhibition rates in lung tumor-bearing mice.

Conclusion

EtpP-CDDP NLCs improved tumor-cell uptake, cytotoxicity, and tumor-inhibition efficiency, and could be used as a promising drug-delivery system for lung cancer combination therapy.

AMP-activated protein kinase - a journey from 1 to 100 downstream targets

A casual decision made one evening in 1976, in a bar near the Biochemistry Department at the University of Dundee, led me to start my personal research journey by following up a paper that suggested that acetyl-CoA carboxylase (ACC) (believed to be a key regulatory enzyme of fatty acid synthesis) was inactivated by phosphorylation by what appeared to be a novel, cyclic AMP-independent protein kinase. This led me to define and name the AMP-activated protein kinase (AMPK) signalling pathway, on which I am still working 46 years later. ACC was the first known downstream target for AMPK, but at least 100 others have now been identified. This article contains some personal reminiscences of that research journey, focussing on: (i) the early days when we were defining the kinase and developing the key tools required to study it; (ii) the late 1990s and early 2000s, an exciting time when we and others were identifying the upstream kinases; (iii) recent times when we have been studying the complex role of AMPK in cancer. The article is published in conjunction with the Sir Philip Randle Lecture of the Biochemical Society, which I gave in September 2022 at the European Workshop on AMPK and AMPK-related kinases in Clydebank, Scotland. During the early years of my research career, Sir Philip acted as a role model, due to his pioneering work on insulin signalling and the regulation of pyruvate dehydrogenase.

Breaking the Bottleneck in Anticancer Drug Development: Efficient Utilization of Synthetic Biology

Natural products have multifarious bioactivities against bacteria, fungi, viruses, cancers and other diseases due to their diverse structures. Nearly 65% of anticancer drugs are natural products or their derivatives. Thus, natural products play significant roles in clinical cancer therapy. With the development of biosynthetic technologies, an increasing number of natural products have been discovered and developed as candidates for clinical cancer therapy. Here, we aim to summarize the anticancer natural products approved from 1950 to 2021 and discuss their molecular mechanisms. We also describe the available synthetic biology tools and highlight their applications in the development of natural products.

Towards establishment of a plant-based model to assess the novel anti-cancerous lead molecule(s): An in silico, in vivo and in vitro assessment of some potential anti-cancerous drugs on Lathyrus sativus L

The drug development process is one of the important aspects of medical biology. The classical lead identification strategy in the way of drug development based on animal cell is time-consuming, expensive and involving ethical issues. The following study aims to develop a novel plant-based screening of drugs. Study shows the efficacy of certain anti-cancerous drugs (Pemetrexed, 5-Fluorouracil, Methotrexate, Topotecan and Etoposide) on a plant-based (Lathyrus sativus L.) system. Two important characteristics of cancer cells were observed in the colchicine-treated polyploid cell and the callus, where the chromosome numbers were unusual and the division of cells were uncontrolled respectively. With increasing concentration, the drugs significantly reduced the mitotic index, ploidy level and callus growth. Increasing Pemetrexed concentration decreased the plant DHFR activity. A decrease in total RNA content was observed in 5-FU and Methotrexate with increasing concentrations of the drugs. Etoposide and Topotecan inhibited plant topoisomerase II and topoisomerase I activities, which was justified through plasmid nicking and comet assay, respectively. Molecular and biochemical study revealed similar results to the animal system. The in silico study had been done, and the structural similarity of drug binding domains of L. sativus and human beings had also been established. The binding site of the selected drugs to the domains of plant target proteins was also determined. Experimental results are significant in terms of the efficacy of known anti-cancerous drugs on the plant-based system. The proposed assay system is a cost-effective, convenient and less time-consuming process for primary screening of anti-cancerous lead molecules.

Multiple approaches to repurposing drugs for neuroblastoma

Neuroblastoma (NB) is the second leading extracranial solid tumor of early childhood with about two-thirds of cases presenting before the age of 5, and accounts for roughly 15 percent of all pediatric cancer fatalities in the United States. Treatments against NB are lacking, resulting in a low survival rate in high-risk patients. A repurposing approach using already approved or clinical stage compounds can be used for diseases for which the patient population is small, and the commercial market limited. We have used Bayesian machine learning, in vitro cell assays, and combination analysis to identify molecules with potential use for NB. We demonstrated that pyronaridine (SH-SY5Y IC50 1.70 µM, SK-N-AS IC50 3.45 µM), BAY 11-7082 (SH-SY5Y IC50 0.85 µM, SK-N-AS IC50 1.23 µM), niclosamide (SH-SY5Y IC50 0.87 µM, SK-N-AS IC50 2.33 µM) and fingolimod (SH-SY5Y IC50 4.71 µM, SK-N-AS IC50 6.11 µM) showed cytotoxicity against NB. As several of the molecules are approved drugs in the US or elsewhere, they may be repurposed more readily for NB treatment. Pyronaridine was also tested in combinations in SH-SY5Y cells and demonstrated an antagonistic effect with either etoposide or crizotinib. Whereas when crizotinib and etoposide were combined with each other they had a synergistic effect in these cells. We have also described several analogs of pyronaridine to explore the structure-activity relationship against cell lines. We describe multiple molecules demonstrating cytotoxicity against NB and the further evaluation of these molecules and combinations using other NB cells lines and in vivo models will be important in the future to assess translational potential.

A high-throughput 384-well CometChip platform reveals a role for 3-methyladenine in the cellular response to etoposide-induced DNA damage

The Comet or single-cell gel electrophoresis assay is a highly sensitive method to measure cellular, nuclear genome damage. However, low throughput can limit its application for large-scale studies. To overcome these limitations, a 96-well CometChip platform was recently developed that increases throughput and reduces variation due to simultaneous processing and automated analysis of 96 samples. To advance throughput further, we developed a 384-well CometChip platform that allows analysis of ∼100 cells per well. The 384-well CometChip extends the capacity by 4-fold as compared to the 96-well system, enhancing application for larger DNA damage analysis studies. The overall sensitivity of the 384-well CometChip is consistent with that of the 96-well system, sensitive to genotoxin exposure and to loss of DNA repair capacity. We then applied the 384-well platform to screen a library of protein kinase inhibitors to probe each as enhancers of etoposide induced DNA damage. Here, we found that 3-methyladenine significantly increased levels of etoposide-induced DNA damage. Our results suggest that a 384-well CometChip is useful for large-scale DNA damage analyses, which may have increased potential in the evaluation of chemotherapy efficacy, compound library screens, population-based analyses of genome damage and evaluating the impact of environmental genotoxins on genome integrity.

Phytochemical Investigation of Egyptian Riverhemp: A Potential Source of Antileukemic Metabolites

As part of our research group’s continuous efforts to find alternative treatments for cancer, the aqueous ethanol extract of Sesbania sesban L. Merr. (SS, Egyptian riverhemp) demonstrated an antileukemic activity against K562 cell line. Bioguided fractionation of SS leaves hydroethanolic extract resulted in the isolation of one new compound (33) named as hederatriol 3-O-β-D-glucuronic acid methyl ester as well as 34 known compounds. Seven compounds ((34), (22), (20), (24), (21), (19), and (35)) showed high antiproliferative effects (IC50 = 22.3, 30.8, 31.3, 33.7, 36.6, 37.5, and 41.5 μM, respectively), while four compounds ((32), (5), (29), and (1)) showed milder activities (IC50 = 56.4, 67.6, 83.3, and 112.3 μM, respectively). A mechanistic study was further carried out on a molecular genetics level against several transcription factors signaling pathways that are incorporated in the incidence of cancer. The results showed that compounds (22) and (21) demonstrated a specific inhibition of Wnt pathway (IC50 = 3.8 and 4.6 μM, respectively), while compound (22) showed a specific inhibition of Smad pathway (IC50 = 3.8 μM). Compound (34) strongly altered the signaling of Smad and E2F pathways (IC50 = 5 μM). The bioactive metabolites were further investigated in silico by docking against several targets related to K562 cell line. The results showed that compounds (22) and (34) exhibited a strong binding affinity towards topoisomerase (docking score = −7.81 and −9.30 Kcal/Mole, respectively). Compounds (22) and (34) demonstrated a strong binding affinity towards EGFR-tyrosine kinase (docking score = −7.12 and −7.35 Kcal/Mole, respectively). Moreover, compound (34) showed a strong binding affinity towards Abl kinase (docking score = −7.05 Kcal/Mole).

Deleting ku80 improves the efficiency of targeted gene editing in Neospora caninum

CRISPR/Cas9 technology has been widely used for gene editing in organisms. Gene deletion of the ku80/ku70 complex can improve the efficiency of gene replacement in Arabidopsis thaliana, Cryptococcus neoformans, and Toxoplasma gondii, which remained elusive in Neospora caninum. Here, we knock out the ku80 gene in Nc1 strain by using CRISPR/Cas9, detect the growth rate and virulence of NcΔku80. Then we compare the efficiency of gene replacements between NcΔku80 and Nc1 strains by transfected with the same HA-tagged plasmids, and the percentage of HA-tagged parasites was investigated by IFA. The results showed that gene targeting efficiency was increased in the NcΔku80 strain via double crossover at several genetic loci, but its growth rate and virulence were unaffected. In conclusion, the NcΔku80 strain can be used as an effective strain for rapid gene editing of N. caninum.

Thiosemicarbazones Can Act Synergistically with Anthracyclines to Downregulate CHEK1 Expression and Induce DNA Damage in Cell Lines Derived from Pediatric Solid Tumors

Anticancer therapy by anthracyclines often leads to the development of multidrug resistance (MDR), with subsequent treatment failure. Thiosemicarbazones have been previously suggested as suitable anthracycline partners due to their ability to overcome drug resistance through dual Pgp-dependent cytotoxicity-inducing effects. Here, we focused on combining anthracyclines (doxorubicin, daunorubicin, and mitoxantrone) and two thiosemicarbazones (DpC and Dp44mT) for treating cell types derived from the most frequent pediatric solid tumors. Our results showed synergistic effects for all combinations of treatments in all tested cell types. Nevertheless, further experiments revealed that this synergism was independent of Pgp expression but rather resulted from impaired DNA repair control leading to cell death via mitotic catastrophe. The downregulation of checkpoint kinase 1 (CHEK1) expression by thiosemicarbazones and the ability of both types of agents to induce double-strand breaks in DNA may explain the Pgp-independent synergism between anthracyclines and thiosemicarbazones. Moreover, the concomitant application of these agents was found to be the most efficient approach, achieving the strongest synergistic effect with lower concentrations of these drugs. Overall, our study identified a new mechanism that offers an avenue for combining thiosemicarbazones with anthracyclines to treat tumors regardless the Pgp status.

Novel therapeutic combinations with PARP inhibitors for small cell lung cancer: A bench-to-bedside review

Small cell lung cancer (SCLC) is treated as a monolithic disease despite the evident intra- and intertumoral heterogeneity. Non-specific DNA-damaging agents have remained the first-line treatment for decades. Recently, emerging transcriptomic and genomic profiling of SCLC tumors identified distinct SCLC subtypes and vulnerabilities towards targeted therapeutics, including inhibitors of the nuclear enzyme poly (ADP-ribose) polymerase (PARPi). SCLC cell lines and tumors exhibited an elevated level of PARP1 protein and mRNA compared to healthy lung tissues and other subtypes of lung tumors. Notable responses to PARPi were also observed in preclinical SCLC models. Clinically, PARPi monotherapy exerted variable benefits for SCLC patients. To date, research is being vigorously conducted to examine predictive biomarkers of PARPi response and various PARPi combination strategies to maximize the clinical utility of PARPi. This narrative review summarizes existing preclinical evidence supporting PARPi monotherapy, combination therapy, and respective translation to the clinic. Specifically, we covered the combination of PARPi with DNA-damaging chemotherapy (cisplatin, etoposide, temozolomide), thoracic radiotherapy, immunotherapy (immune checkpoint inhibitors), and many other novel therapeutic agents that target DNA damage response, tumor microenvironment, epigenetic modulation, angiogenesis, the ubiquitin-proteasome system, or autophagy. Putative biomarkers, such as SLFN11 expression, MGMT methylation, E2F1 expression, and platinum sensitivity, which may be predictive of response to distinct therapeutic combinations, were also discussed. The future of SCLC treatment is undergoing rapid change with a focus on tailored and personalized treatment strategies. Further development of cancer therapy with PARPi will immensely benefit at least a subset of biomarker-defined SCLC patients.

An Adaptive Role for DNA Double-Strand Breaks in Hippocampus-Dependent Learning and Memory

DNA double-strand breaks (DSBs), classified as the most harmful type of DNA damage based on the complexity of repair, lead to apoptosis or tumorigenesis. In aging, DNA damage increases and DNA repair decreases. This is exacerbated in disease, as post-mortem tissue from patients diagnosed with mild cognitive impairment (MCI) or Alzheimer's disease (AD) show increased DSBs. A novel role for DSBs in immediate early gene (IEG) expression, learning, and memory has been suggested. Inducing neuronal activity leads to increases in DSBs and upregulation of IEGs, while increasing DSBs and inhibiting DSB repair impairs long-term memory and alters IEG expression. Consistent with this pattern, mice carrying dominant AD mutations have increased baseline DSBs, and impaired DSB repair is observed. These data suggest an adaptive role for DSBs in the central nervous system and dysregulation of DSBs and/or repair might drive age-related cognitive decline (ACD), MCI, and AD. In this review, we discuss the adaptive role of DSBs in hippocampus-dependent learning, memory, and IEG expression. We summarize IEGs, the history of DSBs, and DSBs in synaptic plasticity, aging, and AD. DSBs likely have adaptive functions in the brain, and even subtle alterations in their formation and repair could alter IEGs, learning, and memory.