Concomitant Inhibition of Cytoprotective Autophagy Augments the Efficacy of Withaferin A in Hepatocellular Carcinoma

Withaferin A, a natural thioredoxin reductase 1 (TrxR1) inhibitor, synergistically enhances the antitumor efficacy of sorafenib through ROS-mediated ER stress and DNA damage in hepatocellular carcinoma cells

BACKGROUND

Sorafenib (Sora), a multi-target tyrosine kinase inhibitor, is widely recognized as a standard chemotherapy treatment for advanced hepatocellular carcinoma (HCC). However, drug resistance mechanisms hinder its anticancer efficacy. Derived from Withania somnifera, Withaferin A (WA) exhibits remarkable anti-tumor properties as a natural bioactive compound. This study aimed to examine the mechanisms that underlie the impacts of Sora and WA co-treatment on HCC.

METHODS

Cell proliferation was evaluated through colony formation and MTT assays. Flow cytometry was employed to determine cellular apoptosis and reactive oxygen species (ROS) levels. The evaluation of apoptosis-related protein levels, DNA damage, and endoplasmic reticulum stress was conducte utilizing IHC staining and western blotting. Moreover, the caspase inhibitor Z-VAD-FMK, ATF4 siRNA, ROS scavenger N-acetyl cysteine (NAC), and TrxR1 shRNA were used to elucidate the underlying signaling pathways. To validate the antitumor effects of Sora/WA co-treatment, in vivo experiments were ultimately executed using Huh7 xenografts.

RESULTS

Sora/WA co-treatment demonstrated significant synergistic antitumor impacts both in vivo and in vitro. Mechanistically, the enhanced antitumor impact of Sora by WA was achieved through the inhibition of TrxR1 activity, resulting in ROS accumulation. Moreover, ROS generation induced the activation of DNA damage and endoplasmic reticulum (ER) stress pathways, eventually triggering cellular apoptosis. Pre-treatment with the antioxidant NAC significantly inhibited ROS generation, ER stress, DNA damage, and apoptosis induced by Sora/WA co-treatment. Additionally, the inhibition of ATF4 by small interfering RNA (siRNA) attenuated Sora/WA co-treatment-induced apoptosis. In vivo, Sora/WA co-treatment significantly suppressed tumor growth in HCC xenograft models and decreased TrxR1 activity in tumor tissues.

CONCLUSION

Our study suggests that WA synergistically enhances the antitumor effect of Sora, offering promising implications for evolving treatment approaches for HCC.

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.

Withanolides: Promising candidates for cancer therapy

Natural products have played a significant role throughout history in the prevention and treatment of numerous diseases, particularly cancers. As a natural product primarily derived from various medicinal plants in the Withania genus, withanolides have been shown in several studies to exhibit potential activities in cancer treatment. Consequently, understanding the molecular mechanism of withanolides could herald the discovery of new anticancer agents. Withanolides have been studied widely, especially in the last 20 years, and attracted the attention of numerous researchers. Currently, over 1200 withanolides have been classified, with approximately a quarter of them having been reported in the literature to be able to modulate the survival and death of cancer cells through multiple avenues. To what extent, though, has the anticancer effects of these compounds been studied? How far are they from being developed into clinical drugs? What are their potential, characteristic features, and challenges? In this review, we elaborate on the current knowledge of natural compounds belonging to this class and provide an overview of their natural sources, anticancer activity, mechanism of action, molecular targets, and implications for anticancer drug research. In addition, direct targets and clinical research to guide the design and implementation of future preclinical and clinical studies to accelerate the application of withanolides have been highlighted.

The Therapeutic Effects of Withaferin A against Cancer: Overview and Updates

Cancer is a rapidly rising health problem among the global population, and this burden causes a significant challenge for public health. Current chemotherapeutic agents have different limitations, including drug resistance and severe side effects, and it demands a robust approach to accessing promising anti-cancer therapeutics. The natural compounds have been extensively studied to identify improved therapeutic agents for cancer therapy. Withaferin A (WA) is a steroidal lactone found in Withania somnifera and possesses anti-inflammatory, antioxidant, anti-angiogenesis, and anticancer properties. Multiple studies have shown that WA treatment attenuated various cancer hallmarks by inducing apoptosis and reducing angiogenesis and metastasis with reduced side effects. WA is a promising agent for the treatment of various cancer, and it targets various signaling pathways. With recent updates, the current review highlights the therapeutic implications of WA and its molecular targets in different cancer.

Can Ashwagandha Benefit the Endocrine System?-A Review

Withania somnifera, also known as Ashwagandha, has been used in traditional medicine for thousands of years. Due to the wide range of its activities, there has been interest in its possible beneficial effects on the human body. It is proved that, among others, Ashwagandha has anti-stress, anti-inflammatory, antimicrobial, anti-cancer, anti-diabetic, anti-obesity, cardioprotective, and hypolipidemic properties. Particularly interesting are its properties reported in the field of psychiatry and neurology: in Alzheimer's disease, Parkinson's disease, multiple sclerosis, depression, bipolar disorder, insomnia, anxiety disorders and many others. The aim of this review is to find and summarize the effect that Ashwagandha root extract has on the endocrine system and hormones. The multitude of active substances and the wide hormonal problems faced by modern society sparked our interest in the topic of Ashwagandha's impact on this system. In this work, we also attempted to draw conclusions as to whether W. somnifera can help normalize the functions of the human endocrine system in the future. The search mainly included research published in the years 2010-2023. The results of the research show that Ashwagandha can have a positive effect on the functioning of the endocrine system, including improving the secretory function of the thyroid gland, normalizing adrenal activity, and multidirectional improvement on functioning of the reproductive system. The main mechanism of action in the latter appears to be based on the hypothalamus-pituitary-adrenal (HPA) axis, as a decrease in cortisol levels and an increase in hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in men were found, which results in stress level reduction and improvement in fertility. In turn, other studies prove that active substances from W. somnifera, acting on the body, cause an increase in the secretion of triiodothyronine (T3) and thyroxine (T4) by the thyroid gland and a subsequent decrease in the level of thyroid-stimulating hormone (TSH) in accordance with the hypothalamus-pituitary-thyroid (HPT) axis. In light of these findings, it is clear that Ashwagandha holds significant promise as a natural remedy for various health concerns, especially those related to the endocrine system. Future research may provide new insights into its mechanisms of action and expand its applications in both traditional and modern medicine. The safety and toxicity of Ashwagandha also remain important issues, which may affect its potential use in specific patient groups.

Withaferin A: A Dietary Supplement with Promising Potential as an Anti-Tumor Therapeutic for Cancer Treatment - Pharmacology and Mechanisms

Cancer, as the leading cause of death worldwide, poses a serious threat to human health, making the development of effective tumor treatments a significant challenge. Natural products continue to serve as crucial resources for drug discovery. Among them, Withaferin A (WA), the most active phytocompound extracted from the renowned dietary supplement Withania somnifera (L.) Dunal, exhibits remarkable anti-tumor efficacy. In this manuscript, we aim to comprehensively summarize the pharmacological characteristics of WA as a potential anti-tumor drug candidate, with the objective of contributing to its further development and the discovery of prospective drugs. Through an extensive review of literature from PubMed, Science Direct, and Web of Science, we have gathered substantial evidence showcasing WA's significant anti-tumor effects against a wide range of cancers in both in vitro and in vivo studies. Mechanistically, WA exerts its anti-tumor influence by inducing cell cycle arrest, apoptosis, autophagy, and ferroptosis. Additionally, it inhibits cell proliferation, cancer stem cells, tumor metastasis, and also suppresses epithelial-mesenchymal transition (EMT) and angiogenesis. Several studies have identified direct target proteins of WA, such as vimentin, Hsp90, annexin II and mFAM72A, while BCR-ABL, Mortalin (mtHsp70), Nrf2, and c-MYB are potential targets of WA. Notwithstanding its remarkable anti-tumor efficacy, there are some limitations associated with WA, including potential toxicity and poor oral bioavailability, which need to be addressed when considering it as an anti-tumor candidate agent. Nevertheless, I given its promising anti-tumor attributes, WA remains an encouraging candidate for future drug development. Unveiling the exact target and comprehensive mechanism of WA's action represents a crucial research direction to pursue in the future.

Implications of Withaferin A for the metastatic potential and drug resistance in hepatocellular carcinoma cells via Nrf2-mediated EMT and ferroptosis

Hepatocellular carcinoma (HCC) constitutes a major global health threat due to the high incidence and mortality. Sorafenib is known as the first-line medication for advanced HCC; however, it only extends the limited benefit for HCC patients as the development of acquired resistance. Withaferin A exerts broad pharmaceutical applications in several cancers. However, its effects on HCC cell metastatic potential and sorafenib resistance remain elusive. Here, we corroborated that Withaferin A greatly restrained cell viability, invasion, vasculogenic mimicry (VM) formation, and VE-cadherin levels in HepG2 and SNU449 cells. Moreover, Withaferin A sensitized sorafenib (SR)-resistant HCC cells to sorafenib. In striking contrast to the parental cells, lower ferroptosis was observed in SR-resistant cells as the lower ROS, MDA, and higher intracellular GSH levels in SR-resistant cells. Of interest, Withaferin A enhanced ferroptosis in SR-resistant cells, which was reversed by ferroptosis antagonist liproxstation-1. Notably, Withaferin A elevated Keap1 expression to mitigate Nrf2 signaling activation-mediated epithelial to mesenchymal transition (EMT) and ferroptosis-related protein xCT expression. Importantly, blockage of the Keap1/Nrf2 signaling overturned Withaferin A-evoked ferroptosis and facilitated sorafenib resistance. In addition, knockdown of Keap1 antagonized the inhibitory efficacy of Withaferin A on HCC cell viability, invasion, and VM formation. Consequently, Withaferin A may attenuate the metastatic potential and sorafenib resistance by regulating Keap1/Nrf2-associated EMT and ferroptosis. Thus, Withaferin A may serve as a promising agent for HCC therapy, especially for advanced HCC.

Metformin Enhances the Anti-Cancer Efficacy of Sorafenib via Suppressing MAPK/ERK/Stat3 Axis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) incidence, as well as related mortality, has been steadily increasing in the USA and across the globe, partly due to the lack of effective therapeutic options for advanced HCC. Though sorafenib is considered standard-of-care for advanced HCC, it only improves median survival by a few months when compared to placebo. Sorafenib is also associated with several unpleasant side effects that often lead to early abatement of therapy. Here, we investigate whether a combination regimen including low-dose sorafenib and a non-toxic dose of anti-diabetic drug metformin can achieve effective inhibition of HCC. Indeed, combining metformin with low-dose sorafenib inhibited growth, proliferation, migration, and invasion potential of HCC cells. We observed a 5.3- and 1.9-fold increase in sub-G1 population in the combination treatment compared to sorafenib alone. We found that the combination of metformin enhanced the efficacy of sorafenib and inhibited the MAPK/ERK/Stat3 axis. Our in vivo studies corroborated the in vitro findings, and mice harboring HepG2-derived tumors showed effective tumor reduction upon treatment with low-dose sorafenib and metformin combination. This work sheds light on a therapeutic strategy aiming to augment sorafenib efficacy or dose-de-escalation that may prove beneficial in circumventing sorafenib resistance as well as minimizing related side effects.

Current methods to analyze lysosome morphology, positioning, motility and function

Since the discovery of lysosomes more than 70 years ago, much has been learned about the functions of these organelles. Lysosomes were regarded as exclusively degradative organelles, but more recent research has shown that they play essential roles in several other cellular functions, such as nutrient sensing, intracellular signalling and metabolism. Methodological advances played a key part in generating our current knowledge about the biology of this multifaceted organelle. In this review, we cover current methods used to analyze lysosome morphology, positioning, motility and function. We highlight the principles behind these methods, the methodological strategies and their advantages and limitations. To extract accurate information and avoid misinterpretations, we discuss the best strategies to identify lysosomes and assess their characteristics and functions. With this review, we aim to stimulate an increase in the quantity and quality of research on lysosomes and further ground-breaking discoveries on an organelle that continues to surprise and excite cell biologists.

Withania somnifera (L.) Dunal: Phytochemistry, structure-activity relationship, and anticancer potential

BACKGROUND

Ayurveda is a highly recognized, well-documented, and well-accepted traditional medicine system. This system utilizes many natural products in various forms for therapeutic purposes. Thousands of plants mentioned in the Ayurvedic system are useful in disease mitigation and health preservation. One potential plant of the Ayurvedic system is "Ashwagandha" [Withania somnifera (L.) Dunal], commonly regarded as Indian Ginseng. It possesses various therapeutic activities, such as neuroprotective, hypoglycemic, hepatoprotective, antiarthritic, and anticancer effects.

PURPOSE

Here we present a comprehensive insight on the anticancer effects of W. somnifera and mechanistic attributes of its bioactive phytocompounds. This review also provides updated information on the clinical studies pertaining to cancer, safety evaluation and opportunities for chemical modifications of withanolides, a group of specialized phytochemicals of W. somnifera.

METHODS

The present study was performed in accordance with the guidelines of the Preferred Reporting Items for Systemic Reviews and Meta-Analysis. Various scientific databases, such as PubMed, Science Direct, Scopus, Google Scholar, were explored for related studies published up to May 2021.

RESULTS

An updated review on the anticancer potential and mechanisms of action of the major bioactive components of W. somnifera, including withanolides, withaferin A and withanone, is presented. Comprehensive information on clinical attributes of W. somnifera and its active components are presented with the structure-activity relationship (SAR) and toxicity evaluation.

CONCLUSION

The outcome of the work clearly indicates that W. somnifera has a significant potential for cancer therapy. The SAR revealed that various withanolides in general and withaferin A in particular have binding energies against various proteins and tremendous potential to serve as the lead for new chemical entities. Nevertheless, additional studies, particularly well-designed clinical trials are required before therapeutic application of withanolides for cancer treatment.

Potential of Withaferin-A, Withanone and Caffeic Acid Phenethyl ester as ATP-competitive inhibitors of BRAF: A bioinformatics study

Serine/threonine-protein kinase B-raf (BRAF) plays a significant role in regulating cell division and proliferation through MAPK/ERK pathway. The constitutive expression of wild-type BRAF (BRAF^WT) and its mutant forms, especially V600E (BRAF^V600E), has been linked to multiple cancers. Various synthetic drugs have been approved and are in clinical trials, but most of them are reported to become ineffective within a short duration. Therefore, combinational therapy involving multiple drugs are often recruited for cancer treatment. However, they lead to toxicity and adverse side effects. In this computational study, we have investigated three natural compounds, namely Withaferin-A (Wi-A), Withanone (Wi-N) and Caffeic Acid Phenethyl ester (CAPE) for anti-BRAF^WT and anti-BRAF^V600E activity. We found that these compounds could bind stably at ATP-binding site in both BRAF^WT and BRAF^V600E proteins. In-depth analysis revealed that these compounds maintained the active conformation of wild-type BRAF protein by inducing αC-helix-In, DFG-In, extended activation segment and well-aligned R-spine residues similar to already known drugs Vemurafenib (VEM), BGB283 and Ponatinib. In terms of binding energy, among the natural compounds, CAPE showed better affinity towards both wild-type and V600E mutant proteins than the other two compounds. These data suggested that CAPE, Wi-A and Wi-N have potential to block constitutive autophosphorylation of BRAF and hence warrant in vitro and in vivo experimental validation.

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Out of all the human cancers approximately 8% involve BRAF mutations.

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The 40–50% of the commercialized drugs in the market are from the natural sources or inspired by it.

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Three natural compounds Withaferin-A , Withanone and Caffeic acid phenethyl ester (CAPE) have been studied against BRAF.

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CAPE binds with higher binding affinity with BRAF wild type protein and BRAF V600E mutant protein than other natural compounds.

HBx induces hepatocellular carcinogenesis through ARRB1-mediated autophagy to drive the G1/S cycle

The hepatitis B virus X protein (HBx) is involved in the process of hepatocellular carcinoma via the activation of various oncogenes. Our previous study indicated that ARBB1 (arrestin beta 1) promotes hepatocellular carcinogenesis (HCC). However, the role of ARRB1 in HBx-related HCC remains unclear. Herein, we identified that ARRB1 was upregulated by HBx in vivo and in vitro. Arrb1 deficiency suppressed HBx-induced hepatocellular carcinogenesis in several mouse models. Furthermore, knockdown of ARRB1 blocked HBx-induced macroautophagic/autophagic flux and disrupted the formation of autophagosomes. ARRB1 interacted with HBx, and the autophagic core protein MAP1LC3/LC3, a scaffolding protein, was essential for complete autophagy. Inhibition of autophagy by 3-methyladenine or interference of ATG5 or ATG7 attenuated HBx-induced cell cycle acceleration and the subsequent proliferative response via the induction of G₁/S arrest. The absence of autophagy abolished the phosphorylation of CDK2 and the activity of the CDK2-CCNE1 complex. Our results demonstrate that ARRB1 plays a critical role in HBV-related HCC via modulating autophagy and the CDKN1B-CDK2-CCNE1-E2F1 axis and indicate that ARRB1 may be a potential therapeutic target for HCC.

Review on anticancerous therapeutic potential of Withania somnifera (L.) Dunal

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera, commonly known as Ashwagandha, is an important medicinal herb belonging to family Solanaceae. It is widely used in folkloric and Ayurvedic medicines since antiquity. Traditionally, the plant is highly practiced throughout the globe as immunomodulator, anti-inflammatory, anti-stress, anti-parkinson, anti-alzheimer, cardio protective, neural and physical health enhancer, neurodefensive, anti-diabetic, aphrodisiac, memory boosting etc. The plant is also effective in combating various types of cancer and other related problems of colon, mammary, lung, prostate, skin, blood, liver and kidney.

AIM OF THIS REVIEW

The present review represents the critical assessment of the literature available on the anticancerous role of W. somnifera. The present study throws light on its diverse chemical compounds and the possible mechanisms of action involved. This review also suggests further research strategies to harness the therapeutic potential of this plant.

MATERIALS AND METHODS

The present review is the outcome of a systematic search of scientific literature about 'Withania somnifera and its role in cancer prevention'. The scientific databases viz. Google Scholar, Science Direct, Pubmed and Web of Science were searched from 2001 to 2019. Textbooks, magazines and newspapers were also consulted. This review summarizes all the published literature about its therapeutic potential for the treatment of different types of cancers.

RESULTS

W. somnifera has been widely used in traditional and ayurvedic medicines for treatment of numerous problems related to health and vitality. The plant is a reservoir of diverse phytoconstituents like alkaloids, steroids, flavonoids, phenolics, nitrogen containing compounds and trace elements. Withanolides are the major alkaloids which renders its anticancer potential due to its highly oxygenated nature. The plant is highly effective in combating various types of cancers viz. colon, mammary, lung, prostate, skin, blood, liver and kidney. Previous studies depict that this plant is more effective against breast cancer followed by colon, lung, prostate and blood cancer. Furthermore, from different clinical studies it has been observed that the active constituents of the plant like withaferin-A, withanolide-D have least toxic effects.

CONCLUSION

The present review confirms the various medicinal values of W. somnifera without any significant side effects. Withaferin-A (WA) and Withanolides are its most promising anticancer compounds that play a major role in apoptosis induction. Keeping in mind the anticancerous potential of this plant, it is suggested that this plant may further be investigated and more clinical studies can be performed.

Withaferin-A Treatment Alleviates TAR DNA-Binding Protein-43 Pathology and Improves Cognitive Function in a Mouse Model of FTLD

Withaferin-A, an active withanolide derived from the medicinal herbal plant Withania somnifera induces autophagy, reduces TDP-43 proteinopathy, and improves cognitive function in transgenic mice expressing mutant TDP-43 modelling FTLD. TDP-43 is a nuclear DNA/RNA-binding protein with cellular functions in RNA transcription and splicing. Abnormal cytoplasmic aggregates of TDP-43 occur in several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and limbic-predominant age-related TDP-43 encephalopathy (LATE). To date, no effective treatment is available for TDP-43 proteinopathies. Here, we tested the effects of withaferin-A (WFA), an active withanolide extracted from the medicinal herbal plant Withania somnifera, in a transgenic mouse model of FTLD expressing a genomic fragment encoding mutant TDP-43G348C. WFA treatment ameliorated the cognitive performance of the TDP-43G348C mice, and it reduced NF-κB activity and neuroinflammation in the brain. WFA alleviated TDP-43 pathology while it boosted the levels of the autophagic marker LC3BII in the brain. These data suggest that WFA and perhaps other autophagy inducers should be considered as potential therapy for neurodegenerative diseases with TDP-43 pathology.

Withaferin A activates TRIM16 for its anti-cancer activity in melanoma

Although selective BRAF inhibitors and novel immunotherapies have improved short-term treatment responses in metastatic melanoma patients, acquired resistance to these therapeutics still represent a major challenge in clinical practice. In this study, we evaluated the efficacy of Withaferin A (WFA), derived from the medicinal plant Withania Somnifera, as a novel therapeutic agent for the treatment of melanoma. WFA showed selective toxicity to melanoma cells compared to non-malignant cells. WFA induced apoptosis, significantly reduced cell proliferation and inhibited migration of melanoma cells. We identified that repression of the tumour suppressor TRIM16 diminished WFA cytotoxicity, suggesting that TRIM16 was in part responsible for the cytotoxic effects of WFA in melanoma cells. Together our data indicates that WFA has potent cytopathic effects on melanoma cells through TRIM16, suggesting a potential therapeutic application of WFA in the disease.

Induction of STK11-dependent cytoprotective autophagy in breast cancer cells upon honokiol treatment

Cancer cells hijack autophagy pathway to evade anti-cancer therapeutics. Many molecular signaling pathways associated with drug-resistance converge on autophagy induction. Honokiol (HNK), a natural phenolic compound purified from Magnolia grandiflora, has recently been shown to impede breast tumorigenesis and, in the present study, we investigated whether breast cancer cells evoke autophagy to modulate therapeutic efficacy and functional networks of HNK. Indeed, breast cancer cells exhibit increased autophagosomes-accumulation, MAP1LC3B-II/LC3B-II-conversion, expression of ATG proteins as well as elevated fusion of autophagosomes and lysosomes upon HNK treatment. Breast cancer cells treated with HNK demonstrate significant growth inhibition and apoptotic induction, and these biological processes are blunted by macroautophagy/autophagy. Consequently, inhibiting autophagosome formation, abrogating autophagosome-lysosome fusion or genetic-knockout of BECN1 and ATG7 effectively increase HNK-mediated apoptotic induction and growth inhibition. Next, we explored the functional impact of tumor suppressor STK11 in autophagy induction in HNK-treated cells. STK11-silencing abrogates LC3B-II-conversion, and blocks autophagosome/lysosome fusion and lysosomal activity as illustrated by LC3B-Rab7 co-staining and DQ-BSA assay. Our results exemplify the cytoprotective nature of autophagy invoked in HNK-treated breast cancer cells and put forth the notion that a combined strategy of autophagy inhibition with HNK would be more effective. Indeed, HNK and chloroquine (CQ) show synergistic inhibition of breast cancer cells and HNK-CQ combination treatment effectively inhibits breast tumorigenesis and metastatic progression. Tumor-dissociated cells from HNK-CQ treated tumors exhibit abrogated invasion and migration potential. Together, these results implicate that breast cancer cells undergo cytoprotective autophagy to circumvent HNK and a combined treatment with HNK and CQ can be a promising therapeutic strategy for breast cancer.

Withania somnifera (L.) Dunal: A potential therapeutic adjuvant in cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal (WS) is one of the moststudied Rasayana botanicals used in Ayurveda practice for its immunomodulatory, anti-aging, adaptogenic, and rejuvenating effects. The botanical is being used for various clinical indications, including cancer. Several studies exploring molecular mechanisms of WS suggest its possible role in improving clinical outcomes in cancer management. Therefore, research on WS may offer new insights in rational development of therapeutic adjuvants for cancer.

AIM OF THIS REVIEW

The review aims at providing a detailed analysis of in silico, in vitro, in vivo, and clinical studies related to WS and cancer. It suggests possible role of WS in regulating molecular mechanisms associated with carcinogenesis. The review discusses potential of WS in cancer management in terms of cancer prevention, anti-cancer activity, and enhancing efficacy of cancer therapeutics.

MATERIAL AND METHODS

The present narrative review offers a critical analysis of published literature on WS studies in cancer. The reported studies were analysed in the context of pathophysiology of cancer, commonly referred as 'cancer hallmarks'. The review attempts to bridge Ayurveda knowledge with biological insights into molecular mechanisms of cancer.

RESULTS

Critical analysisof the published literature suggests an anti-cancer potential of WS with a key role in cancer prevention. The possible mechanisms for these effects are associated with the modulation of apoptotic, proliferative, and metastatic markers in cancer. WS can attenuate inflammatory responses and enzymes involved in invasion and metastatic progression of cancer.The properties of WS are likely to be mediated through withanolides, which may activate tumor suppressor proteins to restrict proliferation of cancer cells. Withanolides also regulate the genomic instability, and energy metabolism of cancer cells. The reported studies indicate the need for deeper understanding of molecular mechanisms of WS in inhibiting angiogenesis and promoting immunosurveillance. Additionally, WS can augment efficacy and safety of cancer therapeutics.

CONCLUSION

The experimentally-supported evidence of immunomodulatory, anti-cancer, adaptogenic, and regenerative attributes of WS suggest its therapeutic adjuvant potential in cancer management. The adjuvant properties of withanolides can modulate multidrug resistance and reverse chemotherapy-induced myelosuppression. These mechanisms need to be further explored in systematically designed translational and clinical studies that will pave the way for integration of WS as a therapeutic adjuvant in cancer management.

The Preparation of Ginsenoside Rg5, Its Antitumor Activity against Breast Cancer Cells and Its Targeting of PI3K

Ginsenosides have been reported to possess various pharmacological effects, including anticancer effects. Nevertheless, there are few reports about the antitumor activity and mechanisms of ginsenoside Rg5 against breast cancer cells. In the present study, the major ginsenoside Rb1 was transformed into the rare ginsenoside Rg5 through enzymatic bioconversion and successive acid-assisted high temperature and pressure processing. Ginsenosides Rb1, Rg3, and Rg5 were investigated for their antitumor effects against five human cancer cell lines via the MTT assay. Among them, Rg5 exhibited the greatest cytotoxicity against breast cancer. Moreover, Rg5 remarkably suppressed breast cancer cell proliferation through mitochondria-mediated apoptosis and autophagic cell death. LC3B-GFP/Lysotracker and mRFP-EGFP-LC3B were utilized to show that Rg5 induced autophagosome-lysosome fusion. Western blot assays further illustrated that Rg5 decreased the phosphorylation levels of PI3K, Akt, mTOR, and Bad and suppressed the PI3K/Akt signaling pathway in breast cancer. Moreover, Rg5-induced apoptosis and autophagy could be dramatically strengthened by the PI3K/Akt inhibitor LY294002. Finally, a molecular docking study demonstrated that Rg5 could bind to the active pocket of PI3K. Collectively, our results revealed that Rg5 could be a potential therapeutic agent for breast cancer treatment.

Phytochemicals Bridging Autophagy Induction and Alpha-Synuclein Degradation in Parkinsonism

Among nutraceuticals, phytochemical-rich compounds represent a source of naturally-derived bioactive principles, which are extensively studied for potential beneficial effects in a variety of disorders ranging from cardiovascular and metabolic diseases to cancer and neurodegeneration. In the brain, phytochemicals produce a number of biological effects such as modulation of neurotransmitter activity, growth factor induction, antioxidant and anti-inflammatory activity, stem cell modulation/neurogenesis, regulation of mitochondrial homeostasis, and counteracting protein aggregation through modulation of protein-folding chaperones and the cell clearing systems autophagy and proteasome. In particular, the ability of phytochemicals in restoring proteostasis through autophagy induction took center stage in recent research on neurodegenerative disorders such as Parkinson’s disease (PD). Indeed, autophagy dysfunctions and α-syn aggregation represent two interdependent downstream biochemical events, which concur in the parkinsonian brain, and which are targeted by phytochemicals administration. Therefore, in the present review we discuss evidence about the autophagy-based neuroprotective effects of specific phytochemical-rich plants in experimental parkinsonism, with a special focus on their ability to counteract alpha-synuclein aggregation and toxicity. Although further studies are needed to confirm the autophagy-based effects of some phytochemicals in parkinsonism, the evidence discussed here suggests that rescuing autophagy through natural compounds may play a role in preserving dopamine (DA) neuron integrity by counteracting the aggregation, toxicity, and prion-like spreading of α-syn, which remains a hallmark of PD.