Ashwagandha derived withanone targets TPX2-Aurora A complex: computational and experimental evidence to its anticancer activity

Molecular Characterization of Cancer Preventive and Therapeutic Potential of Three Antistress Compounds, Triethylene Glycol, Withanone, and Withaferin A

The molecular link between stress and carcinogenesis and the positive outcomes of stress intervention in cancer therapy have recently been well documented. Cancer stem cells (CSCs) facilitate cancer malignancy, drug resistance, and relapse and, hence, have emerged as a new therapeutic target. Here, we aimed to investigate the effect of three previously described antistress compounds (triethylene glycol, TEG; Withanone, Wi-N, and Withaferin A, Wi-A) on the stemness and differentiation characteristics of cancer cells. Breast carcinoma, glioblastoma, and neuroblastoma cells were treated with a non-toxic concentration of TEG (0.1%), Wi-N (5 µM), and Wi-A (0.1 µM) in 2D and 3D cultures. The results demonstrated that TEG, Wi-N, and Wi-A suppressed the stemness properties, which was linked with their inhibition of epithelial-mesenchymal transition (EMT) signaling. In particular, Wi-N and TEG caused a stronger reduction in the self-renewal capability of CSCs than Wi-A, as evidenced by a tumor spheroid formation assay and analyses of stemness-related genes (ALDH1, CD44, NANOG, CD133, SOX2). Furthermore, TEG and Wi-N caused the differentiation of cancer cells. Each of these was supported by (i) the upregulation of KRT18, KRT19, E-cadherin, and downregulation of vimentin in breast carcinoma; (ii) increased levels of GFAP, MAP2, and PSD-95 in astrocytoma; and (iii) increased NeuN, GAP-43, and NF200 levels in neuroblastoma. Furthermore, a reduction in cancer progression-related proteins (PI3K, N-myc) was recorded in treated cells. Our results suggest that TEG and Wi-N may be recruited to target cancer cell stemness and differentiation therapy.

Contribution of AurkA/TPX2 Overexpression to Chromosomal Imbalances and Cancer

The AurkA serine/threonine kinase is a key regulator of cell division controlling mitotic entry, centrosome maturation, and chromosome segregation. The microtubule-associated protein TPX2 controls spindle assembly and is the main AurkA regulator, contributing to AurkA activation, localisation, and stabilisation. Since their identification, AurkA and TPX2 have been described as being overexpressed in cancer, with a significant correlation with highly proliferative and aneuploid tumours. Despite the frequent occurrence of AurkA/TPX2 co-overexpression in cancer, the investigation of their involvement in tumorigenesis and cancer therapy resistance mostly arises from studies focusing only on one at the time. Here, we review the existing literature and discuss the mitotic phenotypes described under conditions of AurkA, TPX2, or AurkA/TPX2 overexpression, to build a picture that may help clarify their oncogenic potential through the induction of chromosome instability. We highlight the relevance of the AurkA/TPX2 complex as an oncogenic unit, based on which we discuss recent strategies under development that aim at disrupting the complex as a promising therapeutic perspective.

Ashwagandha-Induced Programmed Cell Death in the Treatment of Breast Cancer

The aim of this review is to provide experimental evidence for the programmed-death activity of Ashwagandha (Withania somnifera) in the anti-cancer therapy of breast cancer. The literature search was conducted using online electronic databases (Google Scholar, PubMed, Scopus). Collection schedule data for the review article covered the years 2004-2024. Ashwagandha active substances, especially Withaferin A (WA), are the most promising anti-cancer compounds. WS exerts its effect on breast cancer cells by inducing programmed cell death, especially apoptosis, at the molecular level. Ashwagandha has been found to possess a potential for treating breast cancer, especially estrogen receptor/progesterone receptor (ER/PR)-positive and triple-negative breast cancer.

A comprehensive review on role of Aurora kinase inhibitors (AKIs) in cancer therapeutics

Aurora kinases (AURKs) are a family of serine /threonine protein kinases that have a crucial role in cell cycle process mainly in the event of chromosomal segregation, centrosome maturation and cytokinesis. The family consists of three members including Aurora kinase A (AURK-A), Aurora kinase B (AURK-B) and Aurora kinase C (AURK-C). All AURKs contain a conserved kinase domain for their activity but differ in their cellular localization and functions. AURK-A and AURK-B are expressed mainly in somatic cells while the expression of AURK-C is limited to germ cells. AURK-A promotes G2 to M transition of cell cycle by controlling centrosome maturation and mitotic spindle assembly. AURK-B and AURK-C form the chromosome passenger complex (CPC) that ensures proper chromosomal alignments and segregation. Aberrant expression of AURK-A and AURK-B has been detected in several solid tumours and malignancies. Hence, they have become an attractive therapeutic target against cancer. The first part of this review focuses on AURKs structure, functions, subcellular localization, and their role in tumorigenesis. The review also highlights the functional and clinical impact of selective as well as pan kinase inhibitors. Currently, >60 compounds that target AURKs are in preclinical and clinical studies. The drawbacks of existing inhibitors like selectivity, drug resistance and toxicity have also been addressed. Since, majority of inhibitors are Aurora kinase inhibitor (AKI) type-1 that bind to the active (DFGin and Cin) conformation of the kinase, this information may be utilized to design highly selective kinase inhibitors that can be combined with other therapeutic agents for better clinical outcomes.

Phyto-therapeutic potential of Withania somnifera: Molecular mechanism and health implications

Withania somnifera, the plant named Indian ginseng, Ashwagandha, or winter cherry, has been used since ancient times to cure various health ailments. Withania somnifera is rich in constituents belonging to chemical classes like alkaloids, saponins, flavonoids, phenolic acids, and withanolides. Several chemotypes were identified based on their phytochemical composition and credited for their multiple bioactivities. Besides, exhibiting neuroprotective, immunomodulatory, adaptogenic, anti-stress, bone health, plant has shown promising anti-cancer properties. Several withanolides have been reported to play a crucial role in cancer; they target cancer cells by different mechanisms such as modulating the expression of tumor suppressor genes, apoptosis, telomerase expression, and regulating cell signaling pathway. Though, many treatments are available for cancer; however, to date, no assured reliable cure for cancer is made available. Additionally, synthetic drugs may lead to development of resistance in time; therefore, focus on new and natural drugs for cancer therapeutics may prove a longtime effective alternative. This current report is a comprehensive combined analysis upto 2023 with articles focused on bio-activities of plant Withania somnifera from various sources, including national and international government sources. This review focuses on understanding of various mechanisms and pathways to inhibit uncontrolled cell growth by W. somnifera bioactives, as reported in literature. This review provides a recent updated status of the W. somnifera on pharmacological properties in general and anti-cancer in particular and may provide a guiding resource for researchers associated with natural product-based cancer research and healthcare management.

Molecular targets and mechanisms of anti-cancer effects of withanolides

Withanolides are a class of natural products with a steroidal lactone structure that exhibit a broad spectrum of anti-cancer effects. To date, several studies have shown that their possible mechanisms in cancer development and progression are associated with the regulation of cell proliferation, apoptosis, metastasis, and angiogenesis. Withanolides can also attenuate inflammatory responses, as well as modulate the genomic instability and energy metabolism of cancer cells. In addition, they may improve the safety and efficacy of cancer treatments as adjuvants to traditional cancer therapeutics. Herein, we summarize the molecular targets and mechanisms of withanolides in different cancers, as well as their current clinical studies on them.

Computational Identification of BCR-ABL Oncogenic Signaling as a Candidate Target of Withaferin A and Withanone

Withaferin-A (Wi-A), a secondary metabolite extracted from Ashwagandha (Withania somnifera), has been shown to possess anticancer activity. However, the molecular mechanism of its action and the signaling pathways have not yet been fully explored. We performed an inverse virtual screening to investigate its binding potential to the catalytic site of protein kinases and identified ABL as a strong candidate. Molecular docking and molecular dynamics simulations were undertaken to investigate the effects on BCR-ABL oncogenic signaling that is constitutively activated yielding uncontrolled proliferation and inhibition of apoptosis in Chronic Myeloid Leukemia (CML). We found that Wi-A and its closely related withanolide, Withanone (Wi-N), interact at both catalytic and allosteric sites of the ABL. The calculated binding energies were higher in the case of Wi-A at catalytic site (−82.19 ± 5.48) and allosteric site (−67.00 ± 4.96) as compared to the clinically used drugs Imatinib (−78.11 ± 5.21) and Asciminib (−54.00 ± 6.45) respectively. Wi-N had a lesser binding energy (−42.11 ± 10.57) compared to Asciminib at the allosteric site. The interaction and conformational changes, subjected to ligand interaction, were found to be similar to the drugs Imatinib and Asciminib. The data suggested that Ashwagandha extracts containing withanolides, Wi-A and Wi-N may serve as natural drugs for the treatment of CML. Inhibition of ABL is suggested as one of the contributing factors of anti-cancer activity of Wi-A and Wi-N, warranting further in vitro and in vivo experiments.

Molecular mechanism of anti-SARS-CoV2 activity of Ashwagandha-derived withanolides

COVID-19 caused by SARS-CoV-2 corona virus has become a global pandemic. In the absence of drugs and vaccine, and premises of time, efforts and cost required for their development, natural resources such as herbs are anticipated to provide some help and may also offer a promising resource for drug development. Here, we have investigated the therapeutic prospective of Ashwagandha for the COVID-19 pandemic. Nine withanolides were tested in silico for their potential to target and inhibit (i) cell surface receptor protein (TMPRSS2) that is required for entry of virus to host cells and (ii) viral protein (the main protease M^pro) that is essential for virus replication. We report that the withanolides possess capacity to inhibit the activity of TMPRSS2 and M^pro. Furthermore, withanolide-treated cells showed downregulation of TMPRSS2 expression and inhibition of SARS-CoV-2 replication in vitro, suggesting that Ashwagandha may provide a useful resource for COVID-19 treatment.

Keeping abreast about ashwagandha in breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Ashwagandha has been used as an ayurvedic medicine in the form of 'Rasayana' (as a tonic) even before 3000 BCE in India. As per Ayurveda, it has long been used traditionally for the treatment of inflammation, weakness, impotence, pulmonary tuberculosis. This plant is also beneficial in lumbago and leucorrhea in the female. In the recent past, Withania has shown its anti-cancerous activity in various experimental models. In addition, Withania also possesses many other properties such as anti-oxidant, anti-stress, adaptogenic, and regenerative which will eventually be beneficial and safe in treating cancer patients.

AIM OF THE STUDY

This review aims to provide experimental evidence along with a deeper insight into molecular mechanisms of Ashwagandha (Withania somnifera (L.) Dunal) through which it acts as a chemotherapeutic agent against different types of breast cancer.

MATERIALS AND METHODS

Literature searches with the help of electronic online databases (Elsevier, Google Scholar, Scopus, Springer Link, ScienceDirect, ResearchGate, PubMed) were carried out. The timeline for collection of data for the review article was from 2000 to 2019. The plant name was validated from The Plant List (2013). Version 1.1. Published on http://www.theplantlist.org/(accessed 21st March 2020).

RESULTS

Various forms of Withania somnifera were used and several in vitro, in vivo, and clinical studies were reported by researchers. They found ashwagandha to exhibit anti-apoptotic, anti-metastatic, anti-invasive and anti-inflammatory properties and gave the evidence that ashwagandha has a capability for averting and treating breast cancer.

CONCLUSION

Various in vitro and in vivo studies suggested Ashwagandha may possess a potential for treating breast cancer, especially ER/PR positive breast cancer and triple-negative breast cancer. A clinical trial has also been conducted in the past that suggested its potential in refining quality of life in breast cancer patients. Studies directed towards molecular pathways have helped in unravelling the key mechanisms of ashwagandha. Future research should be directed towards translational studies involving breast cancer patients. These will reinforce the ancient power of our Ayurvedic medicine.

COVID19-inhibitory activity of withanolides involves targeting of the host cell surface receptor ACE2: insights from computational and biochemical assays

SARS-CoV-2 outbreak in China in December 2019 and its spread as worldwide pandemic has been a major global health crisis. Extremely high infection and mortality rate has severely affected all sectors of life and derailed the global economy. While drug and vaccine development have been prioritized and have made significant progression, use of phytochemicals and herbal constituents is deemed as a low-cost, safer and readily available alternative. We investigated therapeutic efficacy of eight withanolides (derived from Ashwagandha) against the angiotensin-converting enzyme 2 (ACE2) proteins, a target cell surface receptor for SARS-CoV-2 and report results on the (i) computational analyses including binding affinity and stable interactions with ACE2, occupancy of ACE2 residues in making polar and nonpolar interactions with different withanolides/ligands and (2) in vitro mRNA and protein analyses using human cancer (A549, MCF7 and HSC3) cells. We found that among all withanolides, Withaferin-A, Withanone, Withanoside-IV and Withanoside-V significantly inhibited the ACE2 expression. Analysis of withanolides-rich aqueous extracts derived from Ashwagandha leaves and stem showed a higher ACE2 inhibitory potency of stem-derived extracts. Taken together, we demonstrated the inhibitory potency of Ashwagandha withanolides and its aqueous extracts against ACE2.

Communicated by Ramaswamy H. Sarma

High nuclear TPX2 expression correlates with TP53 mutation and poor clinical behavior in a large breast cancer cohort, but is not an independent predictor of chromosomal instability

BACKGROUND

Targeting Protein for Xenopus Kinesin Like Protein 2 (TPX2) is a microtubule associated protein that functions in mitotic spindle assembly. TPX2 also localizes to the nucleus where it functions in DNA damage repair during S-phase. We and others have previously shown that TPX2 RNA levels are strongly associated with chromosomal instability (CIN) in breast and other cancers, and TPX2 RNA levels have been demonstrated to correlate with aggressive behavior and poor clinical outcome across a range of solid malignancies, including breast cancer.

METHODS

We perform TPX2 IHC on a cohort of 253 primary breast cancers and adopt a clinically amenable scoring system to separate tumors into low, intermediate, or high TPX2 expression. We then correlate TPX2 expression against diverse pathologic parameters and important measures of clinical outcome, including disease-specific and overall survival. We link TPX2 expression to TP53 mutation and evaluate whether TPX2 is an independent predictor of chromosomal instability (CIN).

RESULTS

We find that TPX2 nuclear expression strongly correlates with high grade morphology, elevated clinical stage, negative ER and PR status, and both disease-specific and overall survival. We also show that increased TPX2 nuclear expression correlates with elevated ploidy, supernumerary centrosomes, and TP53 mutation. TPX2 nuclear expression correlates with CIN via univariate analyses but is not independently predictive when compared to ploidy, Ki67, TP53 mutational status, centrosome number, and patient age.

CONCLUSIONS

Our findings demonstrate a strong correlation between TPX2 nuclear expression and aggressive tumor behavior, and show that TPX2 overexpression frequently occurs in the setting of TP53 mutation and elevated ploidy. However, TPX2 expression is not an independent predictor of CIN where it fails to outperform existing clinical and pathologic metrics.

Identification and Characterization of MortaparibPlus-A Novel Triazole Derivative That Targets Mortalin-p53 Interaction and Inhibits Cancer-Cell Proliferation by Wild-Type p53-Dependent and -Independent Mechanisms

p53 has an essential role in suppressing the carcinogenesis process by inducing cell cycle arrest/apoptosis/senescence. Mortalin/GRP75 is a member of the Hsp70 protein family that binds to p53 causing its sequestration in the cell cytoplasm. Hence, p53 cannot translocate to the nucleus to execute its canonical tumour suppression function as a transcription factor. Abrogation of mortalin-p53 interaction and subsequent reactivation of p53's tumour suppression function has been anticipated as a possible approach in developing a novel cancer therapeutic drug candidate. A chemical library was screened in a high-content screening system to identify potential mortalin-p53 interaction disruptors. By four rounds of visual assays for mortalin and p53, we identified a novel synthetic small-molecule triazole derivative (4-[(1E)-2-(2-phenylindol-3-yl)-1-azavinyl]-1,2,4-triazole, henceforth named Mortaparib^Plus). Its activities were validated using multiple bioinformatics and experimental approaches in colorectal cancer cells possessing either wild-type (HCT116) or mutant (DLD-1) p53. Bioinformatics and computational analyses predicted the ability of Mortaparib^Plus to competitively prevent the interaction of mortalin with p53 as it interacted with the p53 binding site of mortalin. Immunoprecipitation analyses demonstrated the abrogation of mortalin-p53 complex formation in Mortaparib^Plus-treated cells that showed growth arrest and apoptosis mediated by activation of p21^WAF1, or BAX and PUMA signalling, respectively. Furthermore, we demonstrate that Mortaparib^Plus-induced cytotoxicity to cancer cells is mediated by multiple mechanisms that included the inhibition of PARP1, up-regulation of p73, and also the down-regulation of mortalin and CARF proteins that play critical roles in carcinogenesis. Mortaparib^Plus is a novel multimodal candidate anticancer drug that warrants further experimental and clinical attention.

Computational Insights into the Potential of Withaferin-A, Withanone and Caffeic Acid Phenethyl Ester for Treatment of Aberrant-EGFR Driven Lung Cancers

The anticancer activities of Withaferin-A (Wi-A) and Withanone (Wi-N) from Ashwagandha and Caffeic Acid Phenethyl Ester (CAPE) from honeybee propolis have been well documented. Here, we examined the binding potential of these natural compounds to inhibit the constitutive phosphorylation of epidermal growth factor receptors (EGFRs). Exon 20 insertion mutants of EGFR, which show resistance to various FDA approved drugs and are linked to poor prognosis of lung cancer patients, were the primary focus of this study. Apart from exon 20 insertion mutants, the potential of natural compounds to serve as ATP competitive inhibitors of wildtype protein and other common mutants of EGFR, namely L858R and exon19del, were also examined. The potential of natural compounds was compared to the positive controls such as erlotinib, TAS6417 and poziotinib. Similar to known inhibitors, Wi-A and Wi-N could displace and binds at the ATP orthosteric site of exon19del, L858R and exon20, while CAPE was limited to wildtype EGFR and exon 20 insertion mutants only. Moreover, the binding free energy of the natural drugs against EGFRs was also comparable to the positive controls. This computational study suggests that Wi-A and Wi-N have potential against multiple mutated EGFRs, warranting further in vitro and in vivo experiments.

Targeting AURKA in Cancer: molecular mechanisms and opportunities for Cancer therapy

Aurora kinase A (AURKA) belongs to the family of serine/threonine kinases, whose activation is necessary for cell division processes via regulation of mitosis. AURKA shows significantly higher expression in cancer tissues than in normal control tissues for multiple tumor types according to the TCGA database. Activation of AURKA has been demonstrated to play an important role in a wide range of cancers, and numerous AURKA substrates have been identified. AURKA-mediated phosphorylation can regulate the functions of AURKA substrates, some of which are mitosis regulators, tumor suppressors or oncogenes. In addition, enrichment of AURKA-interacting proteins with KEGG pathway and GO analysis have demonstrated that these proteins are involved in classic oncogenic pathways. All of this evidence favors the idea of AURKA as a target for cancer therapy, and some small molecules targeting AURKA have been discovered. These AURKA inhibitors (AKIs) have been tested in preclinical studies, and some of them have been subjected to clinical trials as monotherapies or in combination with classic chemotherapy or other targeted therapies.

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.

iTRAQ‑based proteomics analysis of the therapeutic effects of combined anticancer bioactive peptides and oxaliplatin on gastric cancer cells

The combination of chemotherapeutic modalities may be more effective in treating gastric cancer compared with any modality alone. Previous studies have demonstrated that the combination of anticancer bioactive peptides (ACBP) and oxaliplatin (OXA) significantly inhibited the growth of the gastric cancer cell line MKN‑45, promoted the apoptosis of MKN‑45 cells, and caused an irreversible arrest of the MKN‑45 cell cycle in the G2/M phase. In the present study, an isobaric tag for relative and absolute quantitation (iTRAQ)‑based quantitative proteomics technique was used to determine the effect of ACBP‑OXA treatment on the proteomics profile of MKN‑45 cells. Notably, a total of 6,210 proteins were detected. Proteins with a >1.2‑fold change in expression (either up‑ or downregulation) and P<0.05 were considered to be differentially expressed. A total of 256 differentially expressed proteins were identified through alignments with different groups. Compared with the control group, MKN‑45 cells treated with ACBP, OXA and ACBP‑OXA exhibited 17 (10 up‑ and 7 downregulated), 111 (27 up‑ and 84 downregulated) and 128 (53 up‑ and 75 downregulated) differentially expressed proteins, respectively. Of the 256 differentially expressed proteins, 6 (TPX2, NUSAP1, TOP2A, YAP, MKi‑67 and GPC4) were verified by the parallel reaction monitoring method, which revealed that TPX2, NUSAP1, TOP2A, YAP, MKi‑67 and GPC4 expression decreased with ACBP‑OXA treatment. The cellular localization, functional annotation and biological pathways of differentially expressed proteins were examined by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The results indicated that ACBP‑OXA may act through the ribosome or the AMP‑activated protein kinase (AMPK) signaling pathway, and the AMPK signaling pathway may be an important mediator of the inhibitory effects of ACBP‑OXA on MKN‑45 gastric cancer cells. In summary, iTRAQ‑based proteomics analysis of the effect of ACBP‑OXA on MKN‑45 cells may guide future therapeutic strategies for gastric cancer. In addition, the present study may help provide new insights into the therapeutic role of combined ACBP and OXA in gastric cancer.

Folic Acid Receptor-Mediated Targeting Enhances the Cytotoxicity, Efficacy, and Selectivity of Withania somnifera Leaf Extract: In vitro and in vivo Evidence

Nanomedicine holds great potential for drug delivery to achieve more effective and safer cancer treatment. Earlier, we reported that the alcoholic extract of Withania somnifera leaves (i-Extract) has selective cancer cell killing activity. Herein, we developed a folate receptor-targeting i-Extract nanocomplex (FRi-ExNC) that suspends well in water and possesses enhanced selective anticancer activity in both in vitro and in vivo assays. Comparative analyses of folate receptor (FR)-positive and -negative cells revealed that FRi-ExNC caused a stronger decrease in Cyclin D/Cdk4 and anti-apoptotic protein Bcl-2, as well as a higher increase in the growth arrest regulating protein p21^WAF1 and pro-apoptotic protein PARP-1, in FR-enriched cancer cells. Our results demonstrate that FRi-ExNC could be a natural source-based nanomedicine for targeted cancer therapy.

Wild type p53 function in p53Y220C mutant harboring cells by treatment with Ashwagandha derived anticancer withanolides: bioinformatics and experimental evidence

Background

Tumor suppressor p53 protein is frequently mutated in a large majority of cancers. These mutations induce local or global changes in protein structure thereby affecting its binding to DNA. The structural differences between the wild type and mutant p53 thus provide an opportunity to selectively target mutated p53 harboring cancer cells. Restoration of wild type p53 activity in mutants using small molecules that can revert the structural changes have been considered for cancer therapeutics.

Methods

We used bioinformatics and molecular docking tools to investigate the structural changes between the wild type and mutant p53 proteins (p53^V143A, p53^R249S, p53^R273H and p53^Y220C) and explored the therapeutic potential of Withaferin A and Withanone for restoration of wild type p53 function in cancer cells. Cancer cells harboring the specific mutant p53 proteins were used for molecular assays to determine the mutant or wild type p53 functions.

Results

We found that p53^V143A mutation does not show any significant structural changes and was also refractory to the binding of withanolides. p53^R249S mutation critically disturbed the H-bond network and destabilized the DNA binding site. However, withanolides did not show any selective binding to either this mutant or other similar variants. p53^Y220C mutation created a cavity near the site of mutation with local loss of hydrophobicity and water network, leading to functionally inactive conformation. Mutated structure could accommodate withanolides suggesting their conformational selectivity to target p53^Y220C mutant. Using human cell lines containing specific p53 mutant proteins, we demonstrated that Withaferin A, Withanone and the extract rich in these withanolides caused restoration of wild type p53 function in mutant p53^Y220C cells. This was associated with induction of p21^WAF-1-mediated growth arrest/apoptosis.

Conclusion

The study suggested that withanolides may serve as highly potent anticancer compounds for treatment of cancers harboring a p53^Y220C mutation.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1099-x) contains supplementary material, which is available to authorized users.

Mechanistic insights into the anticancer mode of action of an herbal drug

Medicinal plants are a vast repository of natural compounds with therapeutic effects against various ailments. Bioactive compounds of these plants have shown to possess anticancer activities. Cancer is one of the fatal diseases causing premature deaths across the world. Two important metabolites, serpentine, a major secondary metabolite of Rauwolfia serpentina, and amarogentin, isolated from Swertia chirata, are found to possess anticancer properties. A comparable in silico analysis of the two anticancer agents serpentine and amarogentin has been done to evaluate their ability to inhibit two potential molecular targets for cancer, nuclear factor-κB (NF-κB) and cyclo-oxygenase-2 (COX-2). The least binding energies of amarogentin with NF-κB and COX-2 are −7·173 and −7·649, respectively, which are better than that of serpentine. The molecular simulation of amarogentin and serpentine suggests that amarogentin has better binding affinities with both cancer targets. Amarogentin is thermodynamically more stable with COX-2 than with NF-κB. Amarogentin is a potent anticancer agent as evidenced by the inhibition of COX-2. This finding would be beneficial to people with cancer.

Promising Anti-influenza Properties of Active Constituent of Withania somnifera Ayurvedic Herb in Targeting Neuraminidase of H1N1 Influenza: Computational Study

Neuraminidase (NA) is a membrane surface antigen which helps in the release of influenza viruses from the host cells after replication. Anti-influenza drugs such as zanamivir bind with eight highly conserved functional residues (R118, D151, R152, R224, E276, R292, R371, and Y406) in the active site of NA, thus restricting the viral release the from host cells. Binding of the drug in active site inhibits the ability of enzyme to cleave sialic acid residues on the cell membrane. Reports on the emergence of zanamivir-resistant strains of H1N1 Influenza virus necessitated a search for alternative drug candidates, preferably from plant source due to their known benefits such as less or no side effects, availability, and low cost. Withaferin A (WA), an active constituent of Withania somnifera ayurvedic herb, has been shown to have a broad range of medicinal properties including its anti-viral activity. The present study demonstrated that WA has the potential to attenuate the neuraminidase of H1N1 influenza. Our docking and simulation results predicted high binding affinity of the WA toward NA and revealed several interesting molecular interactions with the residues which are catalytically important during molecular dynamic simulations. The results presented in the article could be of high importance for further designing of target-specific anti-influenza drug candidates.

TPX2 as a prognostic indicator and potential therapeutic target in clear cell renal cell carcinoma

OBJECTIVES

Our aims were to determine if targeting protein for Xklp2 (TPX2) is correlated with clear cell renal cell carcinoma (ccRCC) histology and oncologic outcomes using The Cancer Genome Atlas (TCGA) and an institutional tissue microarray (TMA).

METHODS

Clinicopathological data obtained from the TCGA consisted of 415 samples diagnosed with ccRCC. A TMA was constructed from tumors of 207 patients who underwent radical nephrectomy for ccRCC. TPX2 expression by immunohistochemistry on TMA was assessed by a genitourinary pathologist. Clinical data were extracted and linked to TMA cores. TPX2 and Aurora-A mRNA coexpression were evaluated in the TCGA cohort. Overall survival (OS), cancer-specific survival, and recurrence-free survival (RFS) were analyzed using the Kaplan-Meier method and log-rank statistics. Univariate and multivariate analyses were conducted using Cox proportional hazard models.

RESULTS

Median follow-up time for the TCGA cohort was 3.07 years. Aurora-A and TPX2 mRNA coexpression were significantly correlated (Pearson correlation = 0.918). High TPX2 mRNA expression was associated with advanced stage, metastasis, poor OS, and RFS. Median follow-up time for the TMA cohort was 5.3 years. Elevated TPX2 protein expression, defined as greater than 75th percentile staining intensity, was identified in 47/207 (22.7%) patients. Increased TPX2 immunostaining was associated with poor OS (P = 0.0327, 53% 5-year mortality), cancer-specific survival (P<0.01, 47.8% 5-year cancer-specific mortality), RFS (P = 0.0313, 73.6%, 5-year recurrence rate), grade, T stage, and metastasis. Multivariate analysis demonstrated elevated expression served as an independent predictor of RFS (hazard ratio = 3.62 (1.13-11.55), P = 0.029).

CONCLUSIONS

We show TPX2, a regulator of Aurora-A, is associated with high grade and stage of ccRCC, and is an independent predictor of recurrence. Future studies are warranted testing its role in ccRCC biology, and its potential as a therapeutic target.

Aurora-A Kinase: A Potent Oncogene and Target for Cancer Therapy

The Aurora kinase family is comprised of three serine/threonine kinases, Aurora-A, Aurora-B, and Aurora-C. Among these, Aurora-A and Aurora-B play central roles in mitosis, whereas Aurora-C executes unique roles in meiosis. Overexpression or gene amplification of Aurora kinases has been reported in a broad range of human malignancies, pointing to their role as potent oncogenes in tumorigenesis. Aurora kinases therefore represent promising targets for anticancer therapeutics. A number of Aurora kinase inhibitors (AKIs) have been generated; some of which are currently undergoing clinical evaluation. Recent studies have unveiled novel unexpected functions of Aurora kinases during cancer development and the mechanisms underlying the anticancer actions of AKIs. In this review, we discuss the most recent advances in Aurora-A kinase research and targeted cancer therapy, focusing on the oncogenic roles and signaling pathways of Aurora-A kinases in promoting tumorigenesis, the recent preclinical and clinical AKI data, and potential alternative routes for Aurora-A kinase inhibition.

Abrogation of AuroraA-TPX2 by novel natural inhibitors: molecular dynamics-based mechanistic analysis

INTRODUCTION

Cancer is characterized by uncontrolled cell growth and genetic instabilities. The human Aurora-A kinase protein plays a crucial role in spindle assembly during mitosis and is activated by another candidate oncogene, targeting protein for Xklp2 (TPX2). It has been proposed that dissociation of Aurora A-TPX2 complex leads to disruption of mitotic spindle apparatus, thereby preventing cell division and further tumor growth.

MATERIALS AND METHODS

A large natural compound library was docked against the active site of Aurora A-TPX2 complex. The protein-ligand complexes were subjected to molecular dynamics simulation to ascertain their binding stability. The drug properties of the compounds were analyzed to observe their drug-like properties.

RESULTS

The virtual screening of natural compound library yielded two high scoring compounds, the first compound CTOM [ZINC ID: 38143674] (Glide score: -9.49) was stable for 17 ns while the second TTOM (Glide score: -9.07) was stable for 15 ns. While CTOM interacted with His280, Thr288 of Aurora A and Tyr34, Lys38 of TPX2, TTOM interacted with Arg285 and Arg286 in addition to the residues involved with CTOM.

CONCLUSIONS

We report two natural compounds as potential drugs leads for the disruption of this complex. These ligands show a preferable docking score and have many drugs like properties within in the range of 95% of known drugs. The study provides evidence that CTOM and TTOM can efficiently inhibit the TPX2-mediated activation of Aurora A. Thus, it paves way for an elaborate investigation and establishes the importance of computational approaches as time- and cost-effective techniques.

Monocyte Chemoattractant Protein-Induced Protein 1 Overexpression Modulates Transcriptome, Including MicroRNA, in Human Neuroblastoma Cells

The recently discovered MCPIP1 (monocyte chemoattractant protein-induced protein 1), a multidomain protein encoded by the MCPIP1 (ZC3H12A) gene, has been described as a new differentiation factor, a ribonuclease, and a deubiquitination-supporting factor. However, its role in cancer is poorly recognized. Our recent analysis of microarrays data showed a lack of expression of the MCPIP1 transcript in primary neuroblastoma, the most common extracranial solid tumor in children. Additionally, enforced expression of the MCPIP1 gene in BE(2)-C cells caused a significant decrease in neuroblastoma proliferation and viability. Aim of the present study was to further investigate the role of MCPIP1 in neuroblastoma, using expression DNA microarrays and microRNA microarrays. Transient transfections of BE(2)-C cells were used for overexpression of either wild type of MCPIP1 (MCPIP1-wt) or its RN-ase defective mutant (MCPIP1-ΔPIN). We have analyzed changes of transcriptome and next, we have used qRT-PCR to verify mRNA levels of selected genes responding to MCPIP1 overexpression. Additionally, protein levels were determined for some of the selected genes. The choline transporter, CTL1, encoded by the SLC44A1 gene, was significantly repressed at the specific mRNA and protein levels and most importantly this translated into a decreased choline transport in MCPIP1-overexpressing cells. Then, we have found microRNA-3613-3p as the mostly altered in the pools of cells overexpressing the wild type MCPIP1. Next, we analyzed the predicted targets of the miR-3613-3p and validated them using qRT-PCR and western blot. These results indicate that the expression of miR-3613-3p might be regulated by MCPIP1 by cleavage of its precursor form.

Combinations of Ashwagandha leaf extracts protect brain-derived cells against oxidative stress and induce differentiation

BACKGROUND

Ashwagandha, a traditional Indian herb, has been known for its variety of therapeutic activities. We earlier demonstrated anticancer activities in the alcoholic and water extracts of the leaves that were mediated by activation of tumor suppressor functions and oxidative stress in cancer cells. Low doses of these extracts were shown to possess neuroprotective activities in vitro and in vivo assays.

METHODOLOGY/PRINCIPAL FINDINGS

We used cultured glioblastoma and neuroblastoma cells to examine the effect of extracts (alcoholic and water) as well as their bioactive components for neuroprotective activities against oxidative stress. Various biochemical and imaging assays on the marker proteins of glial and neuronal cells were performed along with their survival profiles in control, stressed and recovered conditions. We found that the extracts and one of the purified components, withanone, when used at a low dose, protected the glial and neuronal cells from oxidative as well as glutamate insult, and induced their differentiation per se. Furthermore, the combinations of extracts and active component were highly potent endorsing the therapeutic merit of the combinational approach.

CONCLUSION

Ashwagandha leaf derived bioactive compounds have neuroprotective potential and may serve as supplement for brain health.

TPX2: of spindle assembly, DNA damage response, and cancer

For more than 15 years, TPX2 has been studied as a factor critical for mitosis and spindle assembly. These functions of TPX2 are attributed to its Ran-regulated microtubule-associated protein properties and to its control of the Aurora A kinase. Overexpressed in cancers, TPX2 is being established as marker for the diagnosis and prognosis of malignancies. During interphase, TPX2 resides preferentially in the nucleus where its function had remained elusive until recently. The latest finding that TPX2 plays a role in amplification of the DNA damage response, combined with the characterization of TPX2 knockout mice, open new perspectives to understand the biology of this protein. This review provides an historic overview of the discovery of TPX2 and summarizes its cytoskeletal and signaling roles with relevance to cancer therapies. Finally, the review aims to reconcile discrepancies between the experimental and pathological effects of TPX2 overexpression and advances new roles for compartmentalized TPX2.

UNDERSTANDING THE MOLECULAR MECHANISM OF BINDING MODES OF AURORA A INHIBITORS BY LONG TIME SCALE GPU DYNAMICS

Inhibition of Aurora A kinase interaction is considered to be a promising approach for the discovery of new molecularly targeted cancer therapeutics. In this study, the binding mechanisms of two different inhibitors with a contrasting binding affinity to Aurora A were investigated by long time scale GPU molecular dynamics (MD) simulations coupled with molecular mechanics-Poisson–Boltzmann/generalized Born surface area (MM-PB/GBSA) method. The results showed that the predicted binding free energies of these two complexes were consistent with the experimental data. Through analyzing the individual energy components of binding free energy, we found that the van der Waals contribution was the main force to drive the inhibitor–protein binding and the electrostatic contribution was also a crucial factor for the inhibitor–Aurora A binding. The structural analysis demonstrated that the inhibitor HPM could produce more hydrophobic interaction contacts with Aurora A than that of 2JZ, and the loss of key hydrogen bonds between the inhibitor and residue Arg137 in the hinge region of Aurora A was another important reason for the weaker binding affinity of 2JZ to Aurora A. This study sheds more light on the development of the efficient inhibitors targeting the Aurora A.

Mitotic Stress and Chromosomal Instability in Cancer: The Case for TPX2

Cell cycle deregulation is a common motif in human cancer, and multiple therapeutic strategies are aimed to prevent tumor cell proliferation. Whereas most current therapies are designed to arrest cell cycle progression either in G1/S or in mitosis, new proposals include targeting the intrinsic chromosomal instability (CIN, an increased rate of gain or losses of chromosomes during cell division) or aneuploidy (a genomic composition that differs from diploid) that many tumor cells display. Why tumors cells are chromosomally unstable or aneuploid and what are the consequences of these alterations are not completely clear at present. Several mitotic regulators are overexpressed as a consequence of oncogenic alterations, and they are likely to alter the proper regulation of chromosome segregation in cancer cells. In this review, we propose the relevance of TPX2, a mitotic regulator involved in the formation of the mitotic spindle, in oncogene-induced mitotic stress. This protein, as well as its partner Aurora-A, is frequently overexpressed in human cancer, and its deregulation may participate not only in chromosome numeric aberrations but also in other forms of genomic instability in cancer cells.

Blocking protein kinase C signaling pathway: mechanistic insights into the anti-leishmanial activity of prospective herbal drugs from Withania somnifera

BACKGROUND

Leishmaniasis is caused by several species of leishmania protozoan and is one of the major vector-born diseases after malaria and sleeping sickness. Toxicity of available drugs and drug resistance development by protozoa in recent years has made Leishmaniasis cure difficult and challenging. This urges the need to discover new antileishmanial-drug targets and antileishmanial-drug development.

RESULTS

Tertiary structure of leishmanial protein kinase C was predicted and found stable with a RMSD of 5.8Å during MD simulations. Natural compound withaferin A inhibited the predicted protein at its active site with -28.47 kcal/mol binding free energy. Withanone was also found to inhibit LPKC with good binding affinity of -22.57 kcal/mol. Both withaferin A and withanone were found stable within the binding pocket of predicted protein when MD simulations of ligand-bound protein complexes were carried out to examine the consistency of interactions between the two.

CONCLUSIONS

Leishmanial protein kinase C (LPKC) has been identified as a potential target to develop drugs against Leishmaniasis. We modelled and refined the tertiary structure of LPKC using computational methods such as homology modelling and molecular dynamics simulations. This structure of LPKC was used to reveal mode of inhibition of two previous experimentally reported natural compounds from Withania somnifera - withaferin A and withanone.