Evaluating anticancer properties of Withaferin A—a potent phytochemical

Advances in natural products modulating autophagy influenced by cellular stress conditions and their anticancer roles in the treatment of ovarian cancer

Autophagy is a conservative catabolic process that typically serves a cell-protective function. Under stress conditions, when the cellular environment becomes unstable, autophagy is activated as an adaptive response for self-protection. Autophagy delivers damaged cellular components to lysosomes for degradation and recycling, thereby providing essential nutrients for cell survival. However, this function of promoting cell survival under stress conditions often leads to malignant progression and chemotherapy resistance in cancer. Consequently, autophagy is considered a potential target for cancer therapy. Herein, we aim to review how natural products act as key modulators of autophagy by regulating cellular stress conditions. We revisit various stressors, including starvation, hypoxia, endoplasmic reticulum stress, and oxidative stress, and their regulatory relationship with autophagy, focusing on recent advances in ovarian cancer research. Additionally, we explore how polyphenolic compounds, flavonoids, alkaloids, terpenoids, and other natural products modulate autophagy mediated by stress responses, affecting the malignant biological behavior of cancer. Furthermore, we discuss their roles in ovarian cancer therapy. This review emphasizes the importance of natural products as valuable resources in cancer therapeutics, highlighting the need for further exploration of their potential in regulating autophagy. Moreover, it provides novel insights and potential therapeutic strategies in ovarian cancer by utilizing natural products to modulate autophagy.

Biosynthesis of the triterpenoid withanolides in Withaniasomnifera

Ashwagandha (Withania somnifera L. Dunal) is a versatile medicinal plant of Solanaceae family, renowned for its potent therapeutic properties, due to which it is extensively used in Indian traditional systems of medicine such as Ayurveda. The medicinal properties are attributed to specialized metabolites known as withanolides, which are chemically triterpenoid steroidal lactones. Despite their significance, the biosynthetic pathway of withanolides remains poorly understood. It is hypothesized that withanolides are synthesized through the universal sterol pathway, wherein sterol precursors undergo various biochemical modifications such as hydroxylation, oxidation, cyclization, and glycosylation, yielding a diverse array of downstream withanolides and withanosides. Consequently, comprehending the biosynthetic pathway of withanolides is crucial to facilitate advancements in withanolides productivity through metabolic engineering or synthetic biology approaches. This article aims to provide an update on the efforts made toward understanding withanolides formation and regulation and highlights gaps and approaches to elucidate the withanolides biosynthesis in W. somnifera.

Molecular Insights into the Anticancer Activity of Withaferin-A: The Inhibition of Survivin Signaling

Survivin, a member of the IAP family, functions as a homodimer and inhibits caspases, the key enzymes involved in apoptosis. Several Survivin inhibitors, including YM-155, Debio1143, EM1421, LQZ-7I, and TL32711, have emerged as potential anticancer drugs awaiting validation in clinical trials. Due to the high cost and adverse side effects of synthetic drugs, natural compounds with similar activity have also been in demand. In this study, we conducted molecular docking assays to evaluate the ability of Wi-A and Wi-N to block Survivin dimerization. We found that Wi-A, but not Wi-N, can bind to and prevent the homodimerization of Survivin, similar to YM-155. Therefore, we prepared a Wi-A-rich extract from Ashwagandha leaves (Wi-AREAL). Experimental analyses of human cervical carcinoma cells (HeLa and ME-180) treated with Wi-AREAL (0.05-0.1%) included assessments of viability, apoptosis, cell cycle, migration, invasion, and the expression levels (mRNA and protein) of molecular markers associated with these phenotypes. We found that Wi-AREAL led to growth arrest mediated by the upregulation of p21WAF1 and the downregulation of several proteins (CDK1, Cyclin B, pRb) involved in cell cycle progression. Furthermore, Wi-AREAL treatment activated apoptosis signaling, as evidenced by reduced PARP-1 and Bcl-2 levels, increased procaspase-3, and elevated Cytochrome C. Additionally, treating cells with a nontoxic low concentration (0.01%) of Wi-AREAL inhibited migration and invasion, as well as EMT (epithelial-mesenchymal transition) signaling. By combining computational and experimental approaches, we demonstrate the potential of Wi-A and Wi-AREAL as natural inhibitors of Survivin, which may be helpful in cancer treatment.

Covalent binding of withanolides to cysteines of protein targets

Withanolides represent an important category of natural products with a steroidal lactone core. Many of them contain an α,β-unsaturated carbonyl moiety with a high reactivity toward sulfhydryl groups, including protein cysteine thiols. Different withanolides endowed with marked antitumor and anti-inflammatory have been shown to form stable covalent complexes with exposed cysteines present in the active site of oncogenic kinases (BTK, IKKβ, Zap70), metabolism enzymes (Prdx-1/6, Pin1, PHGDH), transcription factors (Nrf2, NFκB, C/EBPβ) and other structural and signaling molecules (GFAP, β-tubulin, p97, Hsp90, vimentin, Mpro, IPO5, NEMO, …). The present review analyzed the covalent complexes formed through Michael addition alkylation reactions between six major withanolides (withaferin A, physalin A, withangulatin A, 4β-hydroxywithanolide E, withanone and tubocapsanolide A) and key cysteine residues of about 20 proteins and the resulting biological effects. The covalent conjugation of the α,β-unsaturated carbonyl system of withanolides with reactive protein thiols can occur with a large set of soluble and membrane proteins. It points to a general mechanism, well described with the leading natural product withaferin A, but likely valid for most withanolides harboring a reactive (electrophilic) enone moiety susceptible to react covalently with cysteinyl residues of proteins. The multiplicity of reactive proteins should be taken into account when studying the mechanism of action of new withanolides. Proteomic and network analyses shall be implemented to capture and compare the cysteine covalent-binding map for the major withanolides, so as to identify the protein targets at the origin of their activity and/or unwanted effects. Screening of the cysteinome will help understanding the mechanism of action and designing cysteine-reactive electrophilic drug candidates.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

Indian Ayurvedic medicine: Overview and application to brain cancer

Ayurveda is the traditional medicine system of India, and has been in practice for millennia. It is a traditional approach that uses 1000's of different plant preparations in various combinations for treatment of human ailments, including cancer. Ethnopharmacological and phytochemical analyses are now elucidating the bioactive constituents of the different plant species and herbal formulations, including ashwagandha, curcumin, guduchi, triphala, and others. To provide an overview of: 1) the ethnopharmacology of Ayurveda and several of its most important plant species and formulations, including pharmacological and molecular mechanisms of its anti-cancer effects; 2) review the literature applying Ayurvedic herbs and formulations to brain tumors. A detailed PubMed search was performed that included publications involving Ayurveda, cancer, ethnopharmacology, phytochemical analysis, molecular analysis, and brain tumors. In recent decades, significant research has begun to elucidate the bioactive compounds of ashwagandha, tumeric, guduchi, and triphala, such as withaferin A, withanolides, curcumin, palmatine, and many others. These compounds and extracts are now being applied to brain tumor cells in vitro and in animal models, with positive signs of anti-cancer activity including reduced cell growth, increased apoptosis, cell cycle arrest, increased differentiation, and inhibition of important internal signal transduction pathways. Several Ayurvedic herbs (ashwagandha, curcumin) have bioactive compounds with significant anti-cancer activity, and are effective in early pre-clinical testing against brain tumor cells in vitro and in animal models. Further pre-clinical testing is warranted, along with advancement into phase I and phase II clinical trials of patients with glioblastoma and other brain tumors.

Withania frutescens (L.) Pauquy, a valuable Mediterranean shrub containing bioactive withanolides

The bushy plant Withania frutescens (L.) Pauquy is well distributed in the West-Mediterranean area, notably in the south of Spain, Algeria and Morocco where is it is used traditionally for the treatment of various human diseases, including diabetes. Unlike the two major species W. somnifera and W. coagulans extensively studied, the genomically close species W. frutescens has been much less investigated. Nevertheless, this shrub species displays a comparable phytochemical profile and marked antioxidant and anti-inflammatory properties, at the origin of reported pharmacological effects and its traditional uses. Here we have analyzed the diversity of biological effects reported with leaves and root extracts of W. frutescens. Hydroalcoholic extracts prepared from the aerial parts of the plant have revealed antihyperglycemic and cell-protective activities along with antimicrobial and anticorrosive effects. The extracts contained diverse polyphenolic compounds and a few alkaloids (calystegines) but most of the observed effects have been attributed to the presence of withanolides which are modified C28 ergostane-type steroids. Our analysis focused in part on specific withanolides found in W. frutescens, in particular an unusual 3-O-sulfated withanolide considered as a potential pro-drug of the major active compound withaferin A (WA) and a lead compound for the development of a potential drug candidate. The mechanism of action of this sulfated WA analogue is discussed. Altogether, our unprecedented extensive analysis of W. frutescens highlighted the pharmacological potential of this atypical medicinal plant. By analogy with the major cultivated Withania species, the market potential of little-known plant is underlined.

The Potential Pharmacological Effects of Natural Product Withaferin A in Cancer: Opportunities and Challenges for Clinical Translation

Cancer is one of the biggest health concerns with a complex pathophysiology. Currently, available chemotherapeutic drugs are showing deleterious side effects, and tumors often show resistance to treatment. Hence, extensive research is required to develop new treatment strategies to fight against cancer. Natural resources from plants are at the forefront of hunting novel drugs to treat various types of cancers. Withaferin A (WA) is a naturally occurring withanolide, a biologically active component obtained from the plant Ashwagandha. Various in vitro and in vivo oncological studies have reported that Withaferin A (WA) has shown protection from cancer. WA shows its activity by inhibiting the growth and proliferation of malignant cells, apoptosis, and inhibiting angiogenesis, metastasis, and cancer stem cells (CSCs). In addition, WA also showed chemo- and radio-sensitizing properties. Besides the beneficiary pharmacological activities of WA, a few aspects like pharmacokinetic properties, safety, and toxicity studies are still lacking, hindering this potent natural product from entering clinical development. In this review, we have summarized the various pharmacological mechanisms shown by WA in in vitro and in vivo cancer studies and the challenges that must be overcome for this potential natural product's clinical translation to be effective.

Emerging trends of phytochemicals as ferroptosis modulators in cancer therapy

Ferroptosis, a novel form of regulated cell death characterized by dependence on iron and lipid peroxidation, has been implicated in a wide range of clinical conditions including neurological diseases, cardiovascular disorders, acute kidney failure, and various types of cancer. Therefore, it is critical to suppress cancer progression and proliferation. Ferroptosis can be triggered in cancer cells and some normal cells by synthetic substances, such as erastin, Ras-selective lethal small molecule-3, or clinical pharmaceuticals. Natural bioactive compounds are traditional drug discovery tools, and some have been therapeutically used as dietary additives or pharmaceutical agents against various malignancies. The fact that natural products have multiple targets and minimal side effects has led to notable advances in anticancer research. Research has indicated that ferroptosis can also be induced by natural compounds during cancer treatment. In this review, we focused on the most recent developments in emerging molecular processes and the significance of ferroptosis in cancer. To provide new perspectives on the future development of ferroptosis-related anticancer medications, we also provide a summary of the implications of natural phytochemicals in triggering ferroptosis through ROS production and ferritinophagy induction in a variety of malignancies.

Revisiting the Multifaceted Therapeutic Potential of Withaferin A (WA), a Novel Steroidal Lactone, W-ferinAmax Ashwagandha, from Withania Somnifera (L) Dunal

Withania somnifera (L.) Dunal, abundant in the Indian subcontinent as Ashwagandha or winter cherry, is a herb of unprecedented therapeutic value. The number of ailments for which crude Ashwagandha extract can be used as a preventive or curative is practically limitless; and this explains why its use has been in vogue in ancient Ayurveda since at-least about four thousand years. The therapeutic potential of Ashwagandha mainly owes from its reservoir of alkaloids (isopelletierine, anaferine), steroidal lactones (withanolides) and saponins with an extra acyl group (sitoindoside VII and VIII). Withaferin A is an exceptionally potent withanolide which is found in high concentrations in W. somnifera plant extracts. The high reactivity of Withaferin A owes to the presence of a C-28 ergostane network with multiple sites of unsaturation and differential oxygenation. It interacts with the effectors of multiple signaling pathways involved in inflammatory response, oxidative stress response, cell cycle regulation and synaptic transmission and has been found to be significantly effective in inducing programmed cell death in cancer cells, restoring cognitive health, managing diabetes, alleviating metabolic disorders, and rejuvenating the overall body homeostasis. Additionally, recent studies suggest that Withaferin A (WA) has the potential to prevent viral endocytosis by sequestering TMPRSS2, the host transmembrane protease, without altering ACE-2 expression. The scope of performing subtle structural modifications in this multi-ring compound is believed to further expand its pharmacotherapeutic horizon. Very recently, a novel, heavy metal and pesticide free formulation of Ashwagandha whole herb extract, with a significant amount of WA, termed W-ferinAmax Ashwagandha, has been developed. The present review attempts to fathom the present and future of this wonder molecule with comprehensive discussion on its therapeutic potential, safety and toxicity.Key teaching pointsWithania somnifera (L.) Dunal is a medicinal plant with versatile therapeutic values.The therapeutic potential of the plant owes to the presence of withanolides such as Withaferin A.Withaferin A is a C-28 ergostane based triterpenoid with multiple reactive sites of therapeutic potential.It is effective against a broad spectrum of ailments including neurodegenerative disorders, cancer, inflammatory and oxidative stress disorders and it also promotes cardiovascular and sexual health.W-ferinAmax Ashwagandha, is a heavy metal and pesticide free Ashwagandha whole herb extract based formulation with significant amount of Withaferin A.

Gut microbiota and metabolite variations in a migraine mouse model

Migraine is a prevalent clinical disorder characterized by recurrent unilateral throbbing headache episodes accompanied by symptoms such as nausea, vomiting, photophobia, and phonophobia. Despite its common occurrence, the diagnosis, pathophysiology, and treatment of migraine remain controversial. Extensive research has implicated the gut microbiota in various central nervous system disorders, including anxiety disorders, depression, and Parkinson's disease. Some studies have also suggested that migraine may stem from disruptions to neurohormones and metabolism. This study aimed to investigate the disparities in gut microbiota and metabolites between migraine mice model and normal mice to shed light on the underlying mechanisms and potential therapeutic approaches. Distinct differences in gut microbial composition were observed between the migraine mouse model and normal mouse, indicating a potential correlation between these variations and the pathogenesis of migraine. This study provides evidence of differences in gut microbiota composition and metabolites between a migraine mouse model and normal mice, which showed that Akkermansiaceae constituted the most abundant taxon in the sham injection mouse group, while Lachnospiraceae constituted the most prevalent group in the migraine mouse model group. The associations between the abundances of Akkermansia muciniphila and Lachnospiraceae bacteria and metabolites suggested their potential roles in the pathogenesis of migraine. The altered abundance of Lachnospiraceae observed in migraine-afflicted mice and its correlations with changes in metabolites suggest that it may affect the host's health. Thus, probiotic therapy emerges as a possible treatment for migraine. Moreover, significant disparities in gut metabolites were observed between the migraine mouse model and normal mice. These alterations encompass multiple metabolic pathways, suggesting that metabolic disturbances may also contribute to the development of migraines.

Integrating network pharmacology and in silico analysis deciphers Withaferin-A's anti-breast cancer potential via hedgehog pathway and target network interplay

This study examines the remarkable effectiveness of Withaferin-A (WA), a withanolide obtained from Withania somnifera (Ashwagandha), in encountering the mortiferous breast malignancy, a global peril. The predominant objective is to investigate WA's intrinsic target proteins and hedgehog (Hh) pathway proteins in breast cancer targeting through the application of in silico computational techniques and network pharmacology predictions. The databases and webtools like Swiss target prediction, GeneCards, DisGeNet and Online Mendelian Inheritance in Man were exploited to identify the common target proteins. The culmination of the WA network and protein-protein interaction network were devised using Stitch and String web tools, through which the drug-target network of 30 common proteins was constructed employing Cytoscape-version 3.9. Enrichment analysis was performed by incorporating Gprofiler, Metascape and Cytoscape plugins. David compounded the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, and enrichment was computed through bioinformatics tools. The 20 pivotal proteins were docked harnessing Glide, Schrodinger Suite 2023-2. The investigation was governed by docking scores and affinity. The shared target proteins underscored the precise Hh and WA network roles with the affirmation enrichment P-value of <0.025. The implications for hedgehog and cancer pathways were profound with enrichment (P < 0.01). Further, the ADMET and drug-likeness assessments assisted the claim. Robust interactions were noticed with docking studies, authenticated through molecular dynamics, molecular mechanics generalized born surface area scores and bonds. The computational investigation emphasized WA's credible anti-breast activity, specifically with Hh proteins, implying stem-cell-level checkpoint restraints. Rigorous testament is imperative through in vitro and in vivo studies.

Anticancer Drug Discovery Based on Natural Products: From Computational Approaches to Clinical Studies

Globally, malignancies cause one out of six mortalities, which is a serious health problem. Cancer therapy has always been challenging, apart from major advances in immunotherapies, stem cell transplantation, targeted therapies, hormonal therapies, precision medicine, and palliative care, and traditional therapies such as surgery, radiation therapy, and chemotherapy. Natural products are integral to the development of innovative anticancer drugs in cancer research, offering the scientific community the possibility of exploring novel natural compounds against cancers. The role of natural products like Vincristine and Vinblastine has been thoroughly implicated in the management of leukemia and Hodgkin's disease. The computational method is the initial key approach in drug discovery, among various approaches. This review investigates the synergy between natural products and computational techniques, and highlights their significance in the drug discovery process. The transition from computational to experimental validation has been highlighted through in vitro and in vivo studies, with examples such as betulinic acid and withaferin A. The path toward therapeutic applications have been demonstrated through clinical studies of compounds such as silvestrol and artemisinin, from preclinical investigations to clinical trials. This article also addresses the challenges and limitations in the development of natural products as potential anti-cancer drugs. Moreover, the integration of deep learning and artificial intelligence with traditional computational drug discovery methods may be useful for enhancing the anticancer potential of natural products.

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.

Differential response of MDA‑MB‑231 breast cancer and MCF10A normal breast cells to cytoskeletal disruption

Metastasis remains a major clinical problem in cancer diagnosis and treatment. Metastasis is the leading cause of cancer‑related mortality but is still poorly understood. Cytoskeletal proteins are considered potential therapeutic targets for metastatic cancer cells because the cytoskeleton serves a key role in the migration and invasion of these cells. Vimentin and F‑actin exhibit several functional similarities and undergo quantitative and structural changes during carcinogenesis. The present study investigated the effects of vimentin and F‑actin deficiency on the survival and motility of breast cancer cells. In metastatic breast cancer cells (MDA‑MB‑231) and breast epithelial cells (MCF10A), vimentin was knocked down by small interfering RNA and F‑actin was depolymerized by latrunculin A, respectively. The effect of reduced vimentin and F‑actin content on cell viability was analyzed using the MTT assay and the proliferative capacity was compared by analyzing the recovery rate. The effect on motility was analyzed based on two processes: The distance traveled by tracking the cell nucleus and the movement of the protrusions. The effects on cell elasticity were measured using atomic force microscopy. Separately reducing vimentin or F‑actin did not effectively inhibit the growth and motility of MDA‑MB‑231 cells; however, when both vimentin and F‑actin were simultaneously deficient, MDA‑MB‑231 cells growth and migration were severely impaired. Vimentin deficiency in MDA‑MB‑231 cells was compensated by an increase in F‑actin polymerization, but no complementary action of vimentin on the decrease in F‑actin was observed. In MCF10A cells, no complementary interaction was observed for both vimentin and F‑actin.

Exploring the efficacy and safety of a novel standardized ashwagandha (Withania somnifera) root extract (Witholytin®) in adults experiencing high stress and fatigue in a randomized, double-blind, placebo-controlled trial

BACKGROUND

Stress is a state of homeostasis in the body being challenged, resulting in a systemic response. It has become more prevalent in recent years and affects mental and physical health.

AIMS

Evaluate the effects of ashwagandha on stress, fatigue, and sex hormones in overweight or mildly obese men and women with self-reported stress and fatigue.

METHODS

Two-arm, parallel-group, 12-week, randomized, double-blind, placebo-controlled trial on overweight or mildly obese men and women aged 40-75 years, supplementing with 200 mg of an ashwagandha root extract (Witholytin®) twice daily.

RESULTS/OUTCOMES

Supplementation with ashwagandha was associated with a significant reduction in stress levels based on the Perceived Stress Scale (primary outcome); however, the improvements were not significantly different to the placebo group (p = 0.867). Based on the Chalder Fatigue Scale, there was a statistically significant reduction in fatigue symptoms in the ashwagandha group compared to the placebo group (p = 0.016), and participants taking ashwagandha also experienced a significant increase in heart rate variability (p = 0.003). However, there were no significant between-group differences in other self-report outcome measures. In the men taking ashwagandha, there was a significant increase in the blood concentrations of free testosterone (p = 0.048) and luteinizing hormone (p = 0.002) compared to the placebo group.

CONCLUSIONS/INTERPRETATION

The results of this study suggest that in overweight middle-to-older age adults experiencing high stress and fatigue, compared to the placebo, ashwagandha did not have a significantly greater impact on perceived stress levels. However, based on secondary outcome measures, it may have anti-fatigue effects. This may be via its impact on the autonomic nervous system. However, further research is required to expand on these current findings.

Recent Progress on Microtubule Degradation Agents

Targeted protein degradation (TPD) has emerged as the most promising approach for the specific knockdown of disease-associated proteins and is achieved by exploiting the cellular quality control machinery. TPD technologies are highly advantageous in overcoming drug resistance as they degrade the whole target protein. Microtubules play important roles in many cellular processes and are among the oldest and most well-established targets for tumor chemotherapy. However, the development of drug resistance, risk of hypersensitivity reactions, and intolerable toxicities severely restrict the clinical applications of microtubule-targeting agents (MTAs). Microtubule degradation agents (MDgAs) operate via completely different mechanisms compared with traditional MTAs and are capable of overcoming drug resistance. The emergence of MDgAs has expanded the scope of TPD and provided new avenues for the discovery of tubulin-targeted drugs. Herein, we summarized the development of MDgAs, and discussed their degradation mechanisms, mechanisms of action on the binding sites, potential opportunities, and challenges.

A critical assessment of the whole plant-based phytotherapeutics from Withania somnifera (L.) Dunal with respect to safety and efficacy vis-a-vis leaf or root extract-based formulation

Withania somnifera (L.) Dunal, popularly known as Ashwagandha or Indian ginseng, is well acclaimed for its health-enhancing effects, including its potent immunomodulatory, anti-inflammatory, neuroprotective, and anti-tumorigenic properties. The prime biological effectors of these attributes are a diverse group of ergostane-based steroidal lactones termed withanolides. Withanones and withanosides are distributed differentially across the plant body, whereas withanolides and withanones are known to be more abundant in leaves, while withanosides are found exclusively in the roots of the plants. Standardized W. somnifera extract is Generally Recognized as Safe (GRAS)-affirmed, however, moderate to severe toxic manifestations may occur at high dosages. Withaferin A, which also happens to be the primary bioactive ingredient for the effectiveness of this plant. There have been contrasting reports regarding the distribution of withaferin A in W. somnifera. While most reports state that the roots of the plant have the highest concentrations of this phytochemical, several others have indicated that leaves can accumulate withaferin A in proportionately higher amounts. A comprehensive survey of the available reports suggests that the biological effects of Ashwagandha are grossly synergistic in nature, with many withanolides together mediating the desired physiological effect. In addition, an assorted formulation of withanolides can also neutralize the toxic effects (if any) associated with withaferin A. This mini-review presents a fresh take on the recent developments regarding the safety and toxicity of the plant, along with a critical assessment of the use of roots against leaves as well as whole plants to develop therapeutic formulations. Going by the currently available scientific evidence, it is safe to infer that the use of whole plant formulations instead of exclusively root or leaf recipes may present the best possible option for further exploration of therapeutic benefits from this novel medicinal plant.HighlightsTherapeutic potential of withanolides owes to the presence of α,β unsaturated ketone which binds to amines, alcohols, and esters and 5β, 6β epoxy group which react with side chain thiols of proteins.At concentrations above NOAEL (no observed adverse effect level), the same mechanisms contribute towards toxicity of the molecule.Although withanosides are found exclusively in roots, whole plants have higher contents of withanones and withanolides.Whole plant-based formulations have other metabolites which can nullify the toxicity associated with roots.Extracts made from whole plants, therefore can holistically impart all therapeutic benefits as well as mitigate toxicity.

Tubulin degradation: Principles, agents, and applications

The microtubule system plays an important role in the mitosis and growth of eukaryotic cells, and it is considered as an appealing and highly successful molecular target for cancer treatment. In fact, microtubule targeting agents, such as paclitaxel and vinblastine, have been approved by FDA for tumor therapy, which have achieved significant therapeutic effects and sales performance. At present, microtubule targeting agents mainly include microtubule-destabilizing agents, microtubule-stabilizing agents, and a few tubulin degradation agents. Although there are few reports about tubulin degradation agents at present, tubulin degradation agents show great potential in overcoming multidrug resistance and reducing neurotoxicity. In addition, some natural drugs could specifically degrade tubulin in tumor cells, but have no effect in normal cells, thus showing a good biosafety profile. Therefore, tubulin degradation agents might exhibit a better application. Currently, some small molecules have been designed to promote tubulin degradation with potent antiproliferative activities, showing the potential for cancer treatment. In this work, we reviewed the reports on tubulin degradation, and focused on the degradation mechanism and important functional groups of chemically synthesized compounds, hoping to provide help for the degradation design of tubulin.

Targeting Cell Signaling Pathways in Lung Cancer by Bioactive Phytocompounds

Lung cancer is a heterogeneous group of malignancies with high incidence worldwide. It is the most frequently occurring cancer in men and the second most common in women. Due to its frequent diagnosis and variable response to treatment, lung cancer was reported as the top cause of cancer-related deaths worldwide in 2020. Many aberrant signaling cascades are implicated in the pathogenesis of lung cancer, including those involved in apoptosis (B cell lymphoma protein, Bcl-2-associated X protein, first apoptosis signal ligand), growth inhibition (tumor suppressor protein or gene and serine/threonine kinase 11), and growth promotion (epidermal growth factor receptor/proto-oncogenes/phosphatidylinositol-3 kinase). Accordingly, these pathways and their signaling molecules have become promising targets for chemopreventive and chemotherapeutic agents. Recent research provides compelling evidence for the use of plant-based compounds, known collectively as phytochemicals, as anticancer agents. This review discusses major contributing signaling pathways involved in the pathophysiology of lung cancer, as well as currently available treatments and prospective drug candidates. The anticancer potential of naturally occurring bioactive compounds in the context of lung cancer is also discussed, with critical analysis of their mechanistic actions presented by preclinical and clinical studies.

Signaling pathways driving ocular malignancies and their targeting by bioactive phytochemicals

Ocular cancers represent a rare pathology. The American Cancer Society estimates that 3,360 cases of ocular cancer occur annually in the United States. The major types of cancers of the eye include ocular melanoma (also known as uveal melanoma), ocular lymphoma, retinoblastoma, and squamous cell carcinoma. While uveal melanoma is one of the primary intraocular cancers with the highest occurrence in adults, retinoblastoma remains the most common primary intraocular cancer in children, and squamous cell carcinoma presents as the most common conjunctival cancer. The pathophysiology of these diseases involves specific cell signaling pathways. Oncogene mutations, tumor suppressor mutations, chromosome deletions/translocations and altered proteins are all described as causal events in developing ocular cancer. Without proper identification and treatment of these cancers, vision loss, cancer spread, and even death can occur. The current treatments for these cancers involve enucleation, radiation, excision, laser treatment, cryotherapy, immunotherapy, and chemotherapy. These treatments present a significant burden to the patient that includes a possible loss of vision and a myriad of side effects. Therefore, alternatives to traditional therapy are urgently needed. Intercepting the signaling pathways for these cancers with the use of naturally occurring phytochemicals could be a way to relieve both cancer burden and perhaps even prevent cancer occurrence. This research aims to present a comprehensive review of the signaling pathways involved in various ocular cancers, discuss current therapeutic options, and examine the potential of bioactive phytocompounds in the prevention and targeted treatment of ocular neoplasms. The current limitations, challenges, pitfalls, and future research directions are also discussed.

Withaferin A, a steroidal lactone, selectively protects normal lymphocytes against ionizing radiation induced apoptosis and genotoxicity via activation of ERK/Nrf-2/HO-1 axis

Increasing use of ionizing radiation (IR) in medicine, industry, agriculture and research ensues potential health hazards if not used properly or contained effectively. However, radioprotectors which are effective in clinical and/or accidental radiation exposures are still elusive. In this direction, we have explored the radioprotective potential of Withaferin A, a plant withanolide, which was recently shown to be safe and well tolerated in cancer patients in a clinical trial and is also known to be a radio-sensitizer in cancer cells. Our results show that, Withaferin A (WA) protected only normal lymphocytes, but not cancer cells, against IR-induced apoptosis and offered radioprotection even when added post-radiation exposure. WA treatment led to significant inhibition of IR-induced caspase-3 activation and decreased IR-induced DNA damage to lymphocytes and bone-marrow cells. WA reduced intracellular ROS and GSH levels and only thiol based anti-oxidants could abrogate the radio-protective effects of WA, indicating a crucial role of cellular/protein thiols in its biological activity. The inability of WA-glutathione adduct to offer radioprotection further underscored the role of cellular thiols. WA induced pro-survival transcription factor, Nrf-2, and expression of cytoprotective genes HO-1, catalase, SOD, peroxiredoxin-2 via ERK. Further, WA administration could rescue mice against radiation induced mortality, DNA damage, increase in micro-nucleated polychromatic erythrocytes (mn-PCEs) and increased ratio of polychromatic erythrocytes (PCEs) to Normochromatic Erythrocytes (NCEs) in bone-marrow, demonstrating its potent in vivo the radio-protective efficacy. In conclusion, WA selectively protects normal cells against IR-induced apoptosis via activation of cytoprotective Nrf-2 pathway.

Withaferin A: A Pleiotropic Anticancer Agent from the Indian Medicinal Plant Withania somnifera (L.) Dunal

Cancer represents the second most deadly disease and one of the most important public health concerns worldwide. Surgery, chemotherapy, radiation therapy, and immune therapy are the major types of treatment strategies that have been implemented in cancer treatment. Unfortunately, these treatment options suffer from major limitations, such as drug-resistance and adverse effects, which may eventually result in disease recurrence. Many phytochemicals have been investigated for their antitumor efficacy in preclinical models and clinical studies to discover newer therapeutic agents with fewer adverse effects. Withaferin A, a natural bioactive molecule isolated from the Indian medicinal plant Withania somnifera (L.) Dunal, has been reported to impart anticancer activities against various cancer cell lines and preclinical cancer models by modulating the expression and activity of different oncogenic proteins. In this article, we have comprehensively discussed the biosynthesis of withaferin A as well as its antineoplastic activities and mode-of-action in in vitro and in vivo settings. We have also reviewed the effect of withaferin A on the expression of miRNAs, its combinational effect with other cytotoxic agents, withaferin A-based formulations, safety and toxicity profiles, and its clinical potential.