Antitumor activity of a novel dual functional podophyllotoxin derivative involved PI3K/AKT/mTOR pathway

Exploring the transformation of chemical components and the discovery of anti-tumor active components in the fruit of Sinopodophyllum hexandrum

Introduction

The fruit of Sinopodophyllum hexandrum (FSH) is derived from Sinopodophyllum hexandrum (Royle) Ying, a plant belonging to the family Berberidaceae of the order Ranunculaceae. It is mainly distributed in the Himalayan alpine region, and born in the understory of forests, and wetlands at the edge of forests, thickets or grasses. FSH grows at an altitude of 2,200-4,300 meters above sea level. Its main pharmacological activities include anti-tumor, anti-inflammation, analgesia, heat clearing and detoxification. In the current experiment, ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was adopted for investigating the chemical components contained in FSH, their transformation patterns in vivo and the potential anti-tumor components, so as to provide an experimental basis for the utilization and development of the resources of FSH.

Methods

The chemical components of FSH and their transformation patterns in vivo were investigated by UPLC-Q-TOF-MS, and the potential anti-tumor active components were predicted from the in vivo transformed components of FSH by using a network pharmacology approach.

Results

Totally 85 chemical components were identified in FSH, among which, 61 were flavonoids and 24 were lignans. The above components were transformed in vivo, including 36 prototype components and 13 transformed products. As revealed by the results of network pharmacology on the prediction of anti-tumor components of FSH, 17 compounds such as Kaempferol, Uralenol, and 8-Prenylquercetin in FSH were used as the potential anti-tumor components.

Conclusion

In this study, the chemical composition, in vivo transformed components of FSH and their metabolites are investigated, and the in vivo transformed components are predicted to have potential anti-tumor pharmacological activities. This study provides the experimental bases for the utilization and development of the resources of FSH.

Comprehensive Biotechnological Strategies for Podophyllotoxin Production from Plant and Microbial Sources

Podophyllotoxin is derived from plant sources and exhibits strong anticancer activity. However, limited natural availability and environmental impacts from traditional extraction methods drive the search for alternative production approaches. This review explores diverse strategies for sustainable podophyllotoxin synthesis, including biosynthesis, semi-synthesis, and biotransformation. Biosynthetic methods involve metabolic pathway engineering in plant or microbial cells, enabling increased yields by manipulating precursor availability and gene expression. Semi-synthetic approaches modify podophyllotoxin precursors or intermediates to enhance therapeutic effects, with derivatives like etoposide and teniposide showing clinical efficacy. Biotransformation, utilising organisms such as endophytic fungi or human hepatic enzymes, enables the transformation of substrates like deoxypodophyllotoxin into podophyllotoxin or its derivatives, yielding compounds with reduced environmental impact and improved purity. The anticancer efficacy of podophyllotoxin and its derivatives stems from multiple mechanisms. These compounds disrupt cell mitosis by inhibiting microtubule assembly, impairing nucleoside transport, and blocking topoisomerase II activity, leading to DNA cleavage and cancer cell apoptosis. Podophyllotoxin and its derivatives also exhibit anti-angiogenesis and anti-metastatic effects through signalling pathway modulation. Notably, derivatives like deoxypodophyllotoxin utilise advanced delivery systems, enhancing targeted efficacy and reducing side effects. Given the varied mechanisms and growing therapeutic applications, optimising biotransformation and delivery techniques remains essential for advancing podophyllotoxin-based therapies. This comprehensive review underscores the compound's potential as a robust anticancer agent and the need for continued research to maximise its production and clinical effectiveness.

Microtubule dynamics in cancer metastasis: Harnessing the underappreciated potential for therapeutic interventions

Microtubules, dynamic cytoskeletal structures crucial for cellular processes, have surfaced as promising targets for cancer therapy owing to their pivotal role in cancer progression and metastasis. This review comprehensively explores the multifaceted landscape of microtubule-targeting drugs and their potential to inihibit cancer metastasis. Although the role of Actin cytoskeleton is well known in controlling metastasis, only recently Microtubules are emerging as a potential controller of metastasis. We delve into the processes at the core of antimetastatic impacts of microtubule-targeting agents, both through direct modulation of microtubules and via alternative pathways. Drawing from in vitro and in vivo studies, we analyze the cytotoxic and antimetastatic doses of various compounds, shedding light on their therapeutic potential. Furthermore, we discuss the emerging class of microtubule targeting drugs, and their role in metastasis inhibition, such as microtubules acetylation inhibitory drugs, particularly histone deacetylase inihibitors and antibody-drug conjugates. Histone deacetylase (HDAC) strengthens the microtubule cytoskeleton through acetylation. Recently, HDAC inhibitors have been discovered to have antimetastatic properties. Here, the role of HDAC inhibitors in stopping metastasis is discussed with respect to microtubule cytoskeleton. Surprisingly, novel antibody conjugates of microtubule-targeting agents, which are in clinical trials, were found to be antimetastatic. This review discusses these antibody conjugates in detail. Additionally, we elucidate the intricate crosstalk between microtubules and other cytoskeletal proteins, unveiling novel therapeutic strategies for metastasis suppression. By providing a wide-ranging overview of the complex interplay between microtubules and cancer metastasis, this review contributes to the comprehension of cancer's biological mechanisms and the development of innovative therapeutic interventions to mitigate metastatic progression.

Podophyllotoxin: Recent Advances in the Development of Hybridization Strategies to Enhance Its Antitumoral Profile

Podophyllotoxin is a naturally occurring cyclolignan isolated from rhizomes of Podophyllum sp. In the clinic, it is used mainly as an antiviral; however, its antitumor activity is even more interesting. While podophyllotoxin possesses severe side effects that limit its development as an anticancer agent, nevertheless, it has become a good lead compound for the synthesis of derivatives with fewer side effects and better selectivity. Several examples, such as etoposide, highlight the potential of this natural product for chemomodulation in the search for new antitumor agents. This review focuses on the recent chemical modifications (2017-mid-2023) of the podophyllotoxin skeleton performed mainly at the C-ring (but also at the lactone D-ring and at the trimethoxyphenyl E-ring) together with their biological properties. Special emphasis is placed on hybrids or conjugates with other natural products (either primary or secondary metabolites) and other molecules (heterocycles, benzoheterocycles, synthetic drugs, and other moieties) that contribute to improved podophyllotoxin bioactivity. In fact, hybridization has been a good strategy to design podophyllotoxin derivatives with enhanced bioactivity. The way in which the two components are joined (directly or through spacers) was also considered for the organization of this review. This comprehensive perspective is presented with the aim of guiding the medicinal chemistry community in the design of new podophyllotoxin-based drugs with improved anticancer properties.

Biosynthesis, total synthesis, and pharmacological activities of aryltetralin-type lignan podophyllotoxin and its derivatives

Covering: up to 2022Podophyllotoxin (PTOX, 1), a kind of aryltetralin-type lignan, was first discovered in the plant Podophyllum peltatum and its structure was clarified by W. Borsche and J. Niemann in 1932. Due to its potent anti-cancer and anti-viral activities, it is considered one of the molecules most likely to be developed into modern drugs. With the increasing market demand and insufficient storage of natural resources, it is crucial to expand the sources of PTOXs. The original extraction method from plants has gradually failed to meet the requirements, and the biosynthesis and total synthesis have become the forward-looking alternatives. As key enzymes in the biosynthetic pathway of PTOXs and their catalytic mechanisms being constantly revealed, it is possible to realize the heterogeneous biosynthesis of PTOXs in the future. Chemical and chemoenzymatic synthesis also provide schemes for strictly controlling the asymmetric configuration of the tetracyclic core. Currently, the pharmacological activities of some PTOX derivatives have been extensively studied, laying the foundation for clinical candidate drugs. This review focuses primarily on the latest research progress in the biosynthesis, total synthesis, and pharmacological activities of PTOX and its derivatives, providing a more comprehensive understanding of these widely used compounds and supporting the future search for clinical applications.

Quercitrin restrains the growth and invasion of lung adenocarcinoma cells by regulating gap junction protein beta 2

Lung adenocarcinoma (LUAD) is the most prevalent subtype of non-small cell lung cancer (NSCLC) with high lethality, and quercitrin exhibits anticancer characteristics. Here, we attempted to uncover the anticancer activity of quercitrin in LUAD. In this work, quercitrin prohibited the cell viability and clone-formation of LUAD cells in vitro. Meanwhile, quercitrin treatment reduced the aggressive phenotypes in LUAD cells. Further, Gap Junction Protein Beta 2 (GJB2) expression was aberrantly higher in LUAD when compared within control tissue. The higher expression of GJB2 is associated with an inferior overall survival for patients with LUAD. Finally, the reintroduction of GJB2 offset the inhibiting influence of quercitrin in LUAD cells. Altogether, these findings disclosed that quercitrin suppressed the growth and metastatic-related traits of LUAD cells partly via regulating GJB2 expression.

Ferritinophagy-Mediated ROS Production Contributed to Proliferation Inhibition, Apoptosis, and Ferroptosis Induction in Action of Mechanism of 2-Pyridylhydrazone Dithiocarbamate Acetate

Reactive oxygen species (ROS) production is involved in the mechanism of action of a number of drugs, but the biological effects of ROS remain to be clarified. Furthermore, ferroptosis involves iron-dependent ROS production that may be derived from ferritinophagy; however, the association between ferroptosis and ferritinophagy has not been fully established. The present study demonstrated that dithiocarbamate derivatives (iron chelators) exhibited antineoplastic properties involving ferritinophagy induction, but whether the underlying mechanisms involved ferroptosis was unknown. To gain insight into the underlying mechanism, a dithiocarbamate derivative, 2-pyridylhydrazone dithiocarbamate s-acetic acid (PdtaA), was prepared. An MTT assay demonstrated that PdtaA inhibited proliferation involving ROS production (IC₅₀ = 23.0 ± 1.5 μM for HepG2 cells). A preliminary mechanistic study revealed that PdtaA induced both apoptosis and cell cycle arrest. Notably, PdtaA also induced ferroptosis via downregulation of GPx4 and xCT, which was first reported for a dithiocarbamate derivative. Moreover, these cellular events were associated with ROS production. To explore the origin of ROS, expression of the ferritinophagy-related genes, ferritin, and nuclear receptor coactivator (NCOA4) were measured. Immunofluorescence and western blotting analysis indicated that PdtaA-induced ferritinophagy may contribute to ROS production. To investigate the role of ferritinophagy, autophagy inhibitor 3-methyladenin or genetic knockdown of NCOA4 was employed to inhibit ferritinophagy, which significantly neutralized the action of PdtaA in both apoptosis and ferroptosis. Taken together, PdtaA-induced cell cycle arrest, apoptosis, and ferroptosis were associated with ferritinophagy.

Podofilox suppresses gastric cancer cell proliferation by regulating cell cycle arrest and the c-Myc/ATG10 axis

Gastric cancer (GC) is a malignancy for which effective therapeutic drugs are limited. Podofilox exhibits antitumor effects in various types of cancer; however, whether it may inhibit GC growth remains unknown. The aim of the present study was to investigate the role of podofilox in GC. Cell Counting Kit-8, colony formation and cell cycle assays were used to detect the role of podofilox on cellular proliferation and the cell cycle, respectively. A microarray was used to detect the transcriptional changes induced by podofilox in GC cells. The results of the present study demonstrated that podofilox inhibited GC cell proliferation and colony formation. The half maximal inhibitory concentration of podofilox in AGS and HGC-27 cells was 2.327 and 1.981 nM, respectively. In addition, treatment with podofilox induced G₀/G₁ cell cycle arrest. Molecular analysis based on microarray data demonstrated that podofilox altered the expression levels of genes involved in the cell cycle, c-Myc and p53 signaling. Autophagy-related 10 (ATG10), which was highly expressed in GC tissues, was also downregulated by podofilox, as demonstrated by the results of the microarray analysis and immunoblotting. To determine the involvement of ATG10 in GC, ATG10 was knocked down in GC cells by small interfering RNA, which suppressed the proliferation and colony formation of GC cells compared with those observed in the control-transfected cells. Taken together, the results of the present study suggested that podofilox may inhibit GC cell proliferation by preventing the cell cycle progression and regulating the c-Myc/ATG10 signaling pathway.

Insight Into the Molecular Mechanism of Podophyllotoxin Derivatives as Anticancer Drugs

Podophyllotoxin (PTOX) is a biologically active compound derived from the podophyllum plant, and both it and its derivatives possess excellent antitumor activity. The PTOX derivatives etoposide (VP-16) and teniposide (VM-26) have been approved by the U.S. Food and Drug Administration (FDA) for cancer treatment, but are far from perfect. Hence, numerous PTOX derivatives have been developed to address the major limitations of PTOX, such as systemic toxicity, drug resistance, and low bioavailability. Regarding their anticancer mechanism, extensive studies have revealed that PTOX derivatives can induce cell cycle G2/M arrest and DNA/RNA breaks by targeting tubulin and topoisomerase II, respectively. However, few studies are dedicated to exploring the interactions between PTOX derivatives and downstream cancer-related signaling pathways, which is reasonably important for gaining insight into the role of PTOX. This review provides a comprehensive analysis of the role of PTOX derivatives in the biological behavior of tumors and potential molecular signaling pathways, aiming to help researchers design and develop better PTOX derivatives.

The ester derivatives obtained by C-ring modification of podophyllotoxin induce apoptosis and inhibited proliferation in PC-3M cells via down-regulation of PI3K/Akt signaling pathway

Podophyllotoxin (PPT) has been reported to have many pharmacological activities, especially its anti-tumor effects. To improve the cytotoxicity and selective effect of PPT, in this study, we have designed and synthesized 20 ester derivatives by introducing Boc-amino acids or organic acids at the C-4 position of PPT. The cytotoxicity of these compounds was evaluated with PC-3M, HemECs, A549, MCF-7 and HepG2 cells. We observed that the proliferation of PC-3M cells was inhibited by all 20 ester derivatives in the largest degree, comparing to the other cell lines. Comparing to PPT (IC₅₀ = 234.90 ± 20.7 nM), eight derivatives had better performance in inhabiting proliferation of PC-3M cells, six of them belong to Boc-amino acid ester derivatives, and the derivative named V-05 (IC₅₀ = 1.28 ± 0.1 nM) had the strongest inhibitation effect. Changes in cell proliferation and apoptotic signaling pathways were studied by DAPI staining, colony formation assay, migration assay, flow cytometry and western blot analysis. We found that V-05 were able to inhibit PC-3M cells proliferation and migration, and induced apoptosis by downregualting p-PI3K, p-Akt and Bcl-2, and upregulating Cleaved caspase-3 and Bax. Our research provides the first insight for the application of PPT derivatives in PC-3M cells, which may offer information to the effective medicine development for human prostate cancer treatment.

The interaction between lipocalin 2 and dipyridine ketone hydrazone dithiocarbamte may influence respective function in proliferation and metastasis-related gene expressions in HepG2 cell

LCN2 (Lipocalins) was first identified as iron transporter through associating with its siderophores and also involved in many cancer metastases, but its function is still paradoxical. We questioned that whether LCN2 might also associate exogenous iron chelator as does in inherent way and the association may influence their respective function. To address this issue, we investigated the effect of LCN2 on action of DpdtC (2,2'-dipyridine ketone hydrazone dithiocarbamte), an iron chelator in proliferation and metastasis-related gene expression. The results showed that exogenous LCN2 and DpdtC could inhibit growth of HepG2 cells, while the combination treatment enhanced their inhibitory effect both in proliferation and colony formation. This encouraged us to investigate the effect of the interaction on metastasis-related gene expression. The results revealed that both LCN2 and DpdtC impaired the wound healing of HepG2, but the inhibitory effect of DpdtC was significantly enhanced upon association with LCN2. Undergoing epithelium-mesenchymal transition (EMT) is a crucial step for cancer metastasis, LCN2 and DpdtC had opposite effects on EMT markers, the binding of DpdtC to LCN2 significantly weakened the regulation of it (or its iron chelate) on EMT markers. To insight into the interaction between LCN2 and DpdtC-iron, fluorescence titration and molecular docking were performed to obtain the association constant (~ 10⁴ M^-1) and thermodynamic parameters (ΔG = - 26.10 kJ/mol). Importantly this study provided evidence that siderophores-loading state of LCN2 may influence its function, which be helpful for understanding the contradictory role of LCN2 in the metastasis of cancer.

Recent advances of podophyllotoxin/epipodophyllotoxin hybrids in anticancer activity, mode of action, and structure-activity relationship: An update (2010-2020)

Podophyllotoxins and epipodophyllotoxins, possess excellent activity against both drug-sensitive and drug-resistant even multidrug-resistant cancer cells via inhibition of tubulin polymerization. Several podophyllotoxin/epipodophyllotoxin derivatives such as etoposide and teniposide have already been applied for cancer therapy, revealing their potential as putative anticancer drugs. Hybridization of podophyllotoxin/epipodophyllotoxin moiety with other anticancer pharmacophores is a promising strategy to develop novel drug candidates so as to overcome drug resistance and improve the specificity, and numerous of podophyllotoxin/epipodophyllotoxin hybrids exhibit excellent in vitro antiproliferative and in vivo anticancer potency. This review emphasizes the recent development of podophyllotoxin/epipodophyllotoxin hybrids with potential application for cancer therapy covering articles published between 2010 and 2020. The mechanisms of action, the critical aspects of design as well as structure-activity relationships were also summarized.

Challenges and potential for improving the druggability of podophyllotoxin-derived drugs in cancer chemotherapy

Covering: up to 2020As a main bioactive component of the Chinese, Indian, and American Podophyllum species, the herbal medicine, podophyllotoxin (PTOX) exhibits broad spectrum pharmacological activity, such as superior antitumor activity and against multiple viruses. PTOX derivatives (PTOXs) could arrest the cell cycle, block the transitorily generated DNA/RNA breaks, and blunt the growth-stimulation by targeting topoisomerase II, tubulin, or insulin-like growth factor 1 receptor. Since 1983, etoposide (VP-16) is being used in frontline cancer therapy against various cancer types, such as small cell lung cancer and testicular cancer. Surprisingly, VP-16 (ClinicalTrials NTC04356690) was also redeveloped to treat the cytokine storm in coronavirus disease 2019 (COVID-19) in phase II in April 2020. The treatment aims at dampening the cytokine storm and is based on etoposide in the case of central nervous system. However, the initial version of PTOX was far from perfect. Almost all podophyllotoxin derivatives, including the FDA-approved drugs VP-16 and teniposide, were seriously limited in clinical therapy due to systemic toxicity, drug resistance, and low bioavailability. To meet this challenge, scientists have devoted continuous efforts to discover new candidate drugs and have developed drug strategies. This review focuses on the current clinical treatment of PTOXs and the prospective analysis for improving druggability in the rational design of new generation PTOX-derived drugs.