A Promising Microtubule Inhibitor Deoxypodophyllotoxin Exhibits Better Efficacy to Multidrug-Resistant Breast Cancer than Paclitaxel via Avoiding Efflux Transport

Plant Origin Source, Content Profile and Bioactivity of Podophyllotoxin as an Important Natural Anticancer Agent

Pharmacological studies have shown that podophyllotoxin (PTOX) has anti-tumor, antiviral, and anti-inflammatory effects. More and more derivatives of PTOX, such as VM-26, NK-611 and GL-331, have gradually been synthesized and are widely used in clinical practice. Sinopodophyllum hexandrum rhizome is rich in PTOX, which is much higher than other PTOX source plants. At present, research on S. hexandrum mainly focuses on artificial cultivation, chemical composition, pharmaceutical value, and the biosynthesis pathway of PTOX. However, the researches are relatively scattered, and systematic review on PTOX is very limited. Therefore, this study performed a comprehensive investigation of the plant origin source, content profile, and biological activities to provide an integrated reference for in-depth research and clinical application of PTOX in the fields of chemistry and pharmacy, which can promote the innovative use of S. hexandrum resources and research and development of new anticancer drugs.

Novel insights into taxane pharmacology: An update on drug resistance mechanisms, immunomodulation and drug delivery strategies

Taxanes are effective in several solid tumors. Paclitaxel, the main clinically available taxane, was approved in the early nineties, for the treatment of ovarian cancer and later on, together with the analogs docetaxel and cabazitaxel, for other malignancies. By interfering with microtubule function and impairing the separation of sister cells at mitosis, taxanes act as antimitotic agents, thereby counteracting the high proliferation rate of cancer cells. The action of taxanes goes beyond their antimitotic function because their main cellular targets, the microtubules, participate in multiple processes such as intracellular transport and cell shape maintenance. The clinical efficacy of taxanes is limited by the development of multiple resistance mechanisms. Among these, extracellular vesicles have emerged as new players. In addition, taxane metronomic schedules shows an impact on the tumor microenvironment reflected by antiangiogenic and immunomodulatory effects, an aspect of growing interest considering their inclusion in treatment regimens with immunotherapeutics. Preclinical studies have paved the bases for synergistic combinations of taxanes both with conventional and targeted agents. A variety of drug delivery strategies have provided novel opportunities to increase the drug activity. The ability of taxanes to orchestrate different cellular effects amenable to modulation suggests novel options to improve cures in lethal malignancies.

Anthriscus sylvestris-Noxious Weed or Sustainable Source of Bioactive Lignans?

Anthriscus sylvestris (L.) Hoffm. (Apiaceae), commonly known as wild chervil, has gained scientific interest owing to its diverse phytochemical profile and potential therapeutic applications. The plant, despite being categorized as a noxious weed, is traditionally used in treating various conditions like headaches, dressing wounds, and as a tonic, antitussive, antipyretic, analgesic, and diuretic. Its pharmacological importance stems from containing diverse bioactive lignans, especially aryltetralins and dibenzylbutyrolactones. One of the main compounds of A. sylvestris, deoxypodophyllotoxin, among its wide-ranging effects, including antitumor, antiproliferative, antiplatelet aggregation, antiviral, anti-inflammatory, and insecticidal properties, serves as a pivotal precursor to epipodophyllotoxin, crucial in the semisynthesis of cytostatic agents like etoposide and teniposide. The main starting compound for these anticancer medicines was podophyllotoxin, intensively isolated from Sinopodophyllum hexandrum, now listed as an endangered species due to overexploitation. Since new species are being investigated as potential sources, A. sylvestris emerges as a highly promising candidate owing to its abundant lignan content. This review summarizes the current knowledge on A. sylvestris, investigating its biological and morphological characteristics, and pharmacological properties. Emphasizing the biological activities and structure-activity relationship, this review underscores its therapeutic potential, thus encouraging further exploration and utilization of this valuable plant resource.

The discovery of water-soluble indazole derivatives as potent microtubule polymerization inhibitors

Taking a previously discovered indazole derivative 1 as a lead, systematic structural modifications were performed with an indazole core at the 1- and 6-positions to improve its aqueous solubility. Among the designed indazole derivatives, 6-methylpyridin-3-yl indazole derivative 8l and 1H-indol-4-yl indazole derivative 8m exhibited high potency in the low nanomolar range against A549, Huh-7, and T24 cancer cells, including Taxol-resistant variant cells (A549/Tax). As a hydrochloride salt, 8l exhibited much improved aqueous solubility, and its log P value fell into a favorable range. In mechanistic studies, 8l impeded tubulin polymerization through interacting with the colchicine site, resulting in cell cycle arrest and cellular apoptosis. In addition, compared to lead compound 1, 8l reduced cell migration and led to more potent inhibition of tumor growth in vivo without apparent toxicity. In summary, indazole derivative 8l could work as a potential anticancer agent and deserves further investigation for cancer therapy.

A recent antitumor story of podophyllotoxin derivatives targeting tubulin: an update (2017-2022)

So far, numerous tubulin-targeted podophyllotoxin congeners were designed and synthesized to overcome the poor water-solubility and improve the pharmaceutical characteristics. However, few studies are dedicated to exploring the interaction of tubulin with the downstream signal transduction pathways, which is important for gaining insight into the role of tubulin in the anticancer action of podophyllotoxin-based conjugates. In this review, we described a detailed account of all the advances on tubulin targeting-podophyllotoxin derivatives from 2017 and 2022 with in depth knowledge about their antitumor action and potential molecular signaling pathways directly involved in tubulin depolymerization, aiming to help researchers design and develop better anticancer drugs derived from podophyllotoxin. Moreover, we also discussed the associated challenges and future opportunities in this field. Short teaser Recent reviews summarized podophyllotoxin-based analogues, with interaction between tubulin and signal pathways being rarely involved. This review comprehensively sum up how podophyllotoxin derivatives targeting tubulin exert their antitumor action via potential molecular signaling pathways.

Discovery of Novel N-Heterocyclic-Fused Deoxypodophyllotoxin Analogues as Tubulin Polymerization Inhibitors Targeting the Colchicine-Binding Site for Cancer Treatment

Natural products are a major source of anticancer agents and play critical roles in anticancer drug development. Inspired by the complexity-to-diversity strategy, novel deoxypodophyllotoxin (DPT) analogues were designed and synthesized. Among them, compound C3 exhibited the potent antiproliferative activity against four human cancer cell lines with IC₅₀ values in the low nanomolar range. Additionally, it showed marked activity against paclitaxel-resistant MCF-7 cells and A549 cells. Moreover, compound C3 can inhibit tubulin polymerization by targeting the colchicine-binding site of tubulin. Further study revealed that compound C3 could arrest cancer cells in the G₂/M phase and disrupt the angiogenesis in human umbilical vein endothelial cells. Meanwhile, C3 remarkably inhibited cancer cell motility and migration, as well as considerably inhibited tumor growth in MCF-7 and MCF-7/TxR xenograft model without obvious toxicity. Collectively, these results indicated that compound C3 may be a promising tubulin polymerization inhibitor development for cancer treatment.

Juniperus sabina L. as a Source of Podophyllotoxins: Extraction Optimization and Anticholinesterase Activities

Juniperus sabina L. (J. sabina) has been an important plant in traditional medicine since ancient times. Its needles are rich in podophyllotoxin, a precursor compound to anti-tumor drugs. However, no systematic research has been done on J. sabina as a source of podophyllotoxins or their biological action. Hence, extracts of podophyllotoxin and deoxypodophyllotoxin were the main optimization targets using the Box–Behnken design (BBD) and response surface methodology (RSM). The total phenol content and antioxidant activity of J. sabina needle extract were also optimized. Under the optimal process conditions (ratio of material to liquid (RLM) 1:40, 90% methanol, and ultrasonic time 7 min), the podophyllotoxin extraction rate was 7.51 mg/g DW, the highest level reported for Juniperus spp. distributed in China. To evaluate its biological potential, the neuroprotective acetyl- and butyrylcholinease (AChE and BChE) inhibitory abilities were tested. The needle extract exhibited significant anti-butyrylcholinesterase activity (520.15 mg GALE/g extract), which correlated well with the high levels of podophyllotoxin and deoxypodophyllotoxin. This study shows the potential medicinal value of J. sabina needles.

Anti-tumor pharmacology of natural products targeting mitosis

Cancer has been an insurmountable problem in the history of medical science. The uncontrollable proliferation of cancer cells is one of cancer’s main characteristics, which is closely associated with abnormal mitosis. Targeting mitosis is an effective method for cancer treatment. This review summarizes several natural products with anti-tumor effects related to mitosis, focusing on targeting microtubulin, inducing DNA damage, and modulating mitosis-associated kinases. Furthermore, the main disadvantages of several typical compounds, including drug resistance, toxicity to non-tumor tissues, and poor aqueous solubility and pharmacokinetic properties, are also discussed, together with strategies to address them. Improved understanding of cancer cell mitosis and natural products may pave the way to drug development for the treatment of cancer.

A comprehensive insight into the antineoplastic activities and molecular mechanisms of deoxypodophyllotoxin: Recent trends, challenges, and future outlook

Lignans constitute an important group of polyphenols, which have been demonstrated to potently suppress cancer cell proliferation. Numerous in vitro and in vivo studies indicate that deoxypodophyllotoxin as a natural lignan possesses potent anticancer activities against various types of human cancer. The purpose of current review is to provide the reader with the latest findings in understanding the anticancer effects and molecular mechanisms of deoxypodophyllotoxin. This review comprehensively describes the influence of deoxypodophyllotoxin on signaling cascades and molecular targets implicated in cancer cell proliferation and invasion. A number of various signaling molecules and pathways, including apoptosis, necroptosis, cell cycle, angiogenesis, vascular disruption, ROS, MMPs, glycolysis, and microtubules as well as NF-κB, PI3K/Akt/mTOR, and MAPK cascades have been reported to be responsible for the anticancer activities of deoxypodophyllotoxin. The results of present review suggest that the cyclolignan deoxypodophyllotoxin can be developed as a novel and potent anticancer agent, especially as an alternative option for treatment of resistant tumors to chemotherapy.

Chitosan: A versatile bio-platform for breast cancer theranostics

Breast cancer is considered one of the utmost neoplastic diseases globally, with a high death rate of patients. Over the last decades, many approaches have been studied to early diagnose and treat it, such as chemotherapy, hormone therapy, immunotherapy, and MRI and biomarker tests; do not show the optimal efficacy. These existing approaches are accompanied by severe side effects, thus recognizing these challenges, a great effort has been done to find out the new remedies for breast cancer. Main finding: Nanotechnology opened a new horizon to the treatment of breast cancer. Many nanoparticulate platforms for the diagnosis of involved biomarkers and delivering antineoplastic drugs are under either clinical trials or just approved by the Food and Drug Administration (FDA). It is well known that natural phytochemicals are successfully useful to treat breast cancer because these natural compounds are safer, available, cheaper, and have less toxic effects. Chitosan is a biocompatible and biodegradable polymer. Further, it has outstanding features, like chemical functional groups that can easily modify our interest with an exceptional choice of promising applications. Abundant studies were directed to assess the chitosan derivative-based nanoformulation's abilities in delivering varieties of drugs. However, the role of chitosan in diagnostics and theranostics not be obligated. The present servey will discuss the application of chitosan as an anticancer drug carrier such as tamoxifen, doxorubicin, paclitaxel, docetaxel, etc. and also, its role as a theranostics (i.e. photo-responsive and thermo-responsive) moieties. The therapeutic and theranostic potential of chitosan in cancer is promising and it seems that to have a good potential to get to the clinic.

Emerging Biomarkers and Targeted Therapies in Feline Mammary Carcinoma

Feline mammary carcinoma (FMC) is a common aggressive malignancy with a low survival rate that lacks viable therapeutic options beyond mastectomy. Recently, increasing efforts have been made to understand the molecular mechanisms underlying FMC development, using the knowledge gained from studies on human breast cancer to discover new diagnostic and prognostic biomarkers, thus reinforcing the utility of the cat as a cancer model. In this article, we review the current knowledge on FMC pathogenesis, biomarkers, and prognosis factors and offer new insights into novel therapeutic options for HER2-positive and triple-negative FMC subtypes.

Deoxypodophyllotoxin Inhibits Non-Small Cell Lung Cancer Cell Growth by Reducing HIF-1α-Mediated Glycolysis

Cancer cell proliferation is a metabolically demanding process that requires high rate of glycolysis to support anabolic growth. Deoxypodophyllotoxin (DPT) is a natural flavonolignan with various pharmacological activities, including antitumor effect. However, whether DPT affects the metabolic reprogramming of cancer cells is unknown. The purpose of this study is to investigate the role of DPT on non-small cell lung cancer (NSCLC) and to explore whether HIF-1α-mediated glycolysis is involved in its mechanism of action.The level of HIF-1α mRNA and protein in NSCLC cells following DPT treatment was detected using qRT-PCR and western blotting, respectively. Cell Counting Kit-8 (CCK-8) and caspase-3 activity assays were performed to analyze cell proliferation and apoptosis. The underlying molecular mechanism was identified by dual luciferase assay, Western blotting, qRT-PCR, glucose consumption, lactate production, and immunoprecipitation. A murine NSCLC model was used to clarify the effect of DPT treatment on tumor cell proliferation. Our findings showed that DPT treatment inhibited NSCLC cell growth in a dose- and time-dependent manner. Further analysis suggested that DPT treatment inhibited HIF-1α signaling pathway by Parkin-mediated protein degradation in NSCLC cells. DPT treatment significantly decreased glucose consumption and lactate production. In addition, DPT treatment reduced the expression of HIF-1α target genes, including GLUT1, HK2 and LDHA, resulting in reduction in glycolysis. We further revealed that DPT-induced cell growth inhibition and increased glucose and lactate levels could be reversed by overexpressing HIF-1α. Additionally, we found that DPT repressed NSCLC growth and GLUT1, HK2 and LDHA expression in vivo. Overall, this study suggested that DPT inhibited NSCLC growth by preventing HIF-1α-mediated glycolysis.

Surface plasmon resonance biosensor combined with lentiviral particle stabilization strategy for rapid and specific screening of P-Glycoprotein ligands

A novel surface plasmon resonance-based P-gp ligand screening system (SPR-PLSS) combined with lentiviral particle (LVP) stabilization strategy was constructed to screen out potential P-gp inhibitors from natural products. Firstly, we constructed LVPs with high and low expression levels of P-gp. The LVPs can ensure the natural conformation of P-gp based on the principle that LVPs germinated from packaging cells will contain cell membrane fragments and P-gp they carry. Then the LVPs with high P-gp expression for active channel and LVPs with low P-gp expression for reference channel were immobilized on CM5 chip respectively. The affinity detection was thus carried out with the signal reduction on the two channels. The P-gp inhibitors, Valspodar (Val) and cyclosporin (CsA), as positive compounds, were detected to characterize the chip's activity, and the K_D of Val and CsA were 14.09 μM and 16.41 μM, respectively. Forty compounds from natural product library were screened using the SPR CM5 chip, and magnolol (Mag), honokiol (Hon), and resveratrol (Res) were screened out as potential P-gp ligands, showing a significant response signal. This work presented a novel P-gp ligand screening system based on LVP-immobilized biosensor to rapidly screen out P-gp ligands from natural product library. Compared with traditional cell experiments which the screening time may take up to several days, our method only takes several hours. Furthermore, this study has also provided solid evidences to support that some complicated membrane proteins would apply to the lentivirus-based SPR screening system.

Alleviation of Multidrug Resistance by Flavonoid and Non-Flavonoid Compounds in Breast, Lung, Colorectal and Prostate Cancer

The aim of the manuscript is to discuss the influence of plant polyphenols in overcoming multidrug resistance in four types of solid cancers (breast, colorectal, lung and prostate cancer). Effective treatment requires the use of multiple toxic chemotherapeutic drugs with different properties and targets. However, a major cause of cancer treatment failure and metastasis is the development of multidrug resistance. Potential mechanisms of multidrug resistance include increase of drug efflux, drug inactivation, detoxification mechanisms, modification of drug target, inhibition of cell death, involvement of cancer stem cells, dysregulation of miRNAs activity, epigenetic variations, imbalance of DNA damage/repair processes, tumor heterogeneity, tumor microenvironment, epithelial to mesenchymal transition and modulation of reactive oxygen species. Taking into consideration that synthetic multidrug resistance agents have failed to demonstrate significant survival benefits in patients with different types of cancer, recent research have focused on beneficial effects of natural compounds. Several phenolic compounds (flavones, phenolcarboxylic acids, ellagitannins, stilbens, lignans, curcumin, etc.) act as chemopreventive agents due to their antioxidant capacity, inhibition of proliferation, survival, angiogenesis, and metastasis, modulation of immune and inflammatory responses or inactivation of pro-carcinogens. Moreover, preclinical and clinical studies revealed that these compounds prevent multidrug resistance in cancer by modulating different pathways. Additional research is needed regarding the role of phenolic compounds in the prevention of multidrug resistance in different types of cancer.

Lower Tubulin Expression in Glioblastoma Stem Cells Attenuates Efficacy of Microtubule-Targeting Agents

Sensitivity to microtubule-targeting agents (MTAs) varies among cancers and predicting the response of individual cancer patients to MTAs remains challenging. As microtubules possess vast molecular heterogeneity generated by tubulin isotypes and their post-translational modifications, we questioned whether this heterogeneity can impact MTA sensitivity. We investigated microtubule heterogeneity in 15 glioblastoma cell lines and measured sensitivity of orthogonal MTAs using a per-division growth rate inhibition method that corrects for the confounding effects of variable cell proliferation rates. We found that the tubulin profile is unique for each glioblastoma cell line and that the total α- and β-tubulin levels impact on MTA sensitivity. The baseline levels of α- and β-tubulin were up to 20% lower in cells that were not effectively killed by MTAs. We report that lower α/β-tubulin expression is associated with lack of cell differentiation and increased expression of stemness markers. The dedifferentiated stem-like cells with low α/β-tubulin levels survive MTAs treatment via reversible nonmutational dormancy. Our findings provide novel insights into the relationships between microtubules and MTAs and lay a foundation for better understanding of the sensitivity of cancer cells to MTAs.

Breast Cancer Resistance Protein and Multidrug Resistance Protein 2 Determine the Disposition of Esculetin-7-O-Glucuronide and 4-Methylesculetin-7-O-Glucuronide

Esculetin (ET)-7-O-glucuronide (ET-G) and 4-methylesculetin (4-ME)-7-O-glucuronide (4-ME-G) are the main glucuronide of ET and 4-ME, respectively. The disposition mediated by efflux transporters for glucuronide has significant influence on the pharmacokinetic profile and efficacy of bioactive compounds. In the current study, transporter gene knockout mice and Caco-2 cells were used to explore the effects of breast cancer resistance protein (BCRP) and multidrug resistance-associated protein 2 (MRP2) on the disposition of ET-G and 4-ME-G. After oral or i.v. administration of ET and 4-ME, the area under the plasma concentration-time curve from time 0 to the last data point or infinity values of ET, 4-ME, and their glucuronides (ET-G and 4-ME-G) were remarkably and significantly increased in most Bcrp1-/- and Mrp2-/- mice compared with those in wild-type FVB mice (P < 0.05). These results were accompanied with a significant increase of maximum plasma concentration values (P < 0.05). In Caco-2 monolayers, the efflux and clearance rates of ET-G and 4-ME-G were markedly reduced by the BCRP inhibitor Ko143 and MRP2 inhibitor MK571 on the apical side (P < 0.05). In an intestinal perfusion study, the excretion of ET-G was significantly decreased in perfusate and increased in plasma in Bcrp1-/- mice compared with those in wild-type FVB mice (P < 0.05). The 4-ME-G concentration was also decreased in the bile in transporter gene knockout mice. ET and 4-ME showed good permeability in both Caco-2 monolayers [apparent permeability (Papp ) ≥ 0.59 × 10-5 cm/s] and duodenum (Papp ≥ 1.81). In conclusion, BCRP and MRP2 are involved in excreting ET-G and 4-ME-G. ET and 4-ME are most likely absorbed via passive diffusion in the intestines.

Biomimetic Shells Endow Sub-50 nm Nanoparticles with Ultrahigh Paclitaxel Payloads for Specific and Robust Chemotherapy

Poor loading capacity and nonspecific tumor accumulation of current drug delivery system remain the critical challenges that prevent nanomedicine from maximizing therapeutic efficacy in cancer treatment. Herein, poly(ester amide) polymers composed of cationic and hydrophobic segments were formulated with a paclitaxel/human serum albumin (PTX/HSA) complex, as well as free PTX, to construct a core-shell nanoparticle (NP) platform with the interior simultaneously reserving PTX and PTX/HSA complex, while the exterior absorbing the PTX/HSA complex. Following systematic screening, the optimized NPs, namely, APP1i@e NPs, exhibited small particle size (43.95 nm), maximal PTX loading (42.23%), excellent dynamic stability (at least 1 week), and acid-triggered release. In vitro results showed that after being trafficked through caveolae-mediated endocytosis, APP1i@e NPs successfully escaped from endo-/lysosomes and then rapidly released cargos in the acidic cytosol, which continued to enhance cytotoxicity by mitochondrial control of apoptosis and suppression of microtubule dynamics. Longer circulation time and superior targeting efficiency post-intravenous injection confirmed that surface PEGylation imparted APP1i@e NPs with the ability to control their pharmacokinetics and biodistribution. The biomimetic shell design with HSA, which enlarged PTX stock and improved biosafety, made APP1i@e NPs more suitable for in vivo applications. Furthermore, in vivo safety and efficacy demonstrated that APP1i@e NPs effectively inhibited the growth of ovarian xenograft tumors, whereas significantly avoiding toxic issues associated with PTX. APP1i@e NPs with surface PEG coating and biomimetic HSA design, therefore, may provide a remarkable improvement in the therapeutic index of taxanes used in the clinic.

Suppression of long noncoding RNA NCK1-AS1 increases chemosensitivity to cisplatin in cervical cancer

Cervical cancer remains a serious health problem till now, with nearly 500,000 women cases diagnosed each year around the world. Long noncoding RNA (lncRNA) is a novel class of RNA transcripts (>200 nucleotides in length) participating in gene transcription, cell proliferation, differentiation, and drug resistance. This study aimed to explore the regulatory relationship among lncRNA NCK1-AS1, miR-134-5p, and MutS protein homolog 2 (MSH2), so that the resistance against cisplatin in cervical cancer treatment could be better understood. Comprehensive lncRNA profiling analysis was performed to screen lncRNAs differentially expressed in cervical cancer. The expression patterns of miR-134-5p, NCK1-AS1, and MSH2 were evaluated in cancerous tissues and adjacent normal tissues obtained from 75 cervical cancer patients. Subsequently, anti-NCK1-AS1 small interfering RNA, miR-134-5p mimics, and miR-134-5p inhibitors were transfected into cervical cancer cells, and the effects of these transcripts on cisplatin resistance and cell apoptosis were investigated. The regulatory relationship among NCK1-AS1, miR-134-5p, and MSH2 was identified using a dual-luciferase reporter gene assay, and the results were further validated by RNA pull-down and RNA immunoprecipitation assays. Based on the microarray data of GSE63514 and GSE27678, NCK1-AS1 was upregulated in cervical cancer. Increased expression of NCK1-AS1, MSH2, and decreased expression of miR-134-5p were observed in cervical cancer tissues. In addition, NCK1-AS1 competitively bound to miR-134-5p to regulate MSH2. Therefore, si-NCK1-AS1 and miR-134-5p mimic both reduced MSH2 activity and increased cisplatin-induced apoptosis in cervical cancer cells. Taken together, NCK1-AS1 may become a novel target in improving the chemotherapeutic response and survival of cervical cancer patients.

The Current Status of the Pharmaceutical Potential of Juniperus L. Metabolites

Background: Plants and their derived natural compounds possess various biological and therapeutic properties, which turns them into an increasing topic of interest and research. Juniperus genus is diverse in species, with several traditional medicines reported, and rich in natural compounds with potential for development of new drugs. Methods: The research for this review were based in the Scopus and Web of Science databases using terms combining Juniperus, secondary metabolites names, and biological activities. This is not an exhaustive review of Juniperus compounds with biological activities, but rather a critical selection taking into account the following criteria: (i) studies involving the most recent methodologies for quantitative evaluation of biological activities; and (ii) the compounds with the highest number of studies published in the last four years. Results: From Juniperus species, several diterpenes, flavonoids, and one lignan were emphasized taking into account their level of activity against several targets. Antitumor activity is by far the most studied, being followed by antibacterial and antiviral activities. Deoxypodophyllotoxin and one dehydroabietic acid derivative appears to be the most promising lead compounds. Conclusions: This review demonstrates the Juniperus species value as a source of secondary metabolites with relevant pharmaceutical potential.