Novel anthraquinone compounds as anticancer agents and their potential mechanism

Anthraquinones-based photocatalysis: A comprehensive review

In recent years, there has been significant interest in photocatalytic technologies utilizing semiconductors and photosensitizers responsive to solar light, owing to their potential for energy and environmental applications. Current efforts are focused on enhancing existing photocatalysts and developing new ones tailored for environmental uses. Anthraquinones (AQs) serve as redox-active electron transfer mediators and photochemically active organic photosensitizers, effectively addressing common issues such as low light utilization and carrier separation efficiency found in conventional semiconductors. AQs offer advantages such as abundant raw materials, controlled preparation, excellent electron transfer capabilities, and photosensitivity, with applications spanning the energy, medical, and environmental sectors. Despite their utility, comprehensive reviews on AQs-based photocatalytic systems in environmental contexts are lacking. In this review, we thoroughly describe the photochemical properties of AQs and their potential applications in photocatalysis, particularly in addressing key environmental challenges like clean energy production, antibacterial action, and pollutant degradation. However, AQs face limitations in practical photocatalytic applications due to their low electrical conductivity and solubility-related secondary contamination. To mitigate these issues, the design and synthesis of graphene-immobilized AQs are highlighted as a solution to enhance practical photocatalytic applications. Additionally, future research directions are proposed to deepen the understanding of AQs' theoretical mechanisms and to provide practical applications for wastewater treatment. This review aims to facilitate mechanistic studies and practical applications of AQs-based photocatalytic technologies and to improve understanding of these technologies.

Biologic activity and treatment resistance to gastrointestinal cancer: the role of circular RNA in autophagy regulation

Circular RNAs (circRNAs) lack the 5'-end methylated guanine cap structure and 3' polyadenylate tail structure, classifying it as a non-coding RNA. With the extensive investigation of circRNA, its role in regulating cell death has garnered significant attention in recent years, establishing it as a recognized participant in cancer's biological processes. Autophagy, an essential pathway in programmed cell death (PCD), involves the formation of autophagosomes using lysosomes to degrade cellular contents under the regulation of various autophagy-related (ATG) genes. Numerous studies have demonstrated that circRNA can modulate the biological activity of cancer cells by influencing the autophagy pathway, exhibiting a dualistic role in suppressing or promoting carcinogenesis. In this review, we comprehensively analyze how autophagy-related circRNA impacts the progression of gastrointestinal cancer (GIC). Additionally, we discuss drug resistance phenomena associated with autophagy regulation in GIC. This review offers valuable insights into exploring potential biological targets for prognosis and treatment strategies related to GIC.

Cytotoxic and Antitumor Agents from Genus Rubia

Genus Rubia is widely distributed in almost all regions of the world, with 36 species and 2 varieties in China. Rubia species, such as Rubia cordifolia, have been used in traditional Chinese medicine for the treatment of diseases since ancient times. In recent years, the study of anticancer effects in traditional Chinese medicine has become a popular topic, and some studies have shown that several Rubia species extracts have cytotoxic and antitumor effects, and some of them have been shown to contain specific antitumor agents. Therefore, this review focuses on the cytotoxic and antitumor effects of the chemical constituents contained in Genus Rubia. Summarized 71 types of chemical substances in 5 categories with the effect of cytotoxicity and antitumor, as well as their structures, targets and mechanisms of action.

Ferrocenyl Azoles: Versatile N-Containing Heterocycles and their Anticancer Activities

The medicinal chemistry of ferrocene has gained its momentum after the discovery of biological activities of ferrocifen and ferroquine. These ferrocenyl drugs have been designed by replacing the aromatic moiety of the organic drugs, tamoxifen and chloroquine respectively, with a ferrocenyl unit. The promising biological activities of these ferrocenyl drugs have paved a path to explore the medicinal applications of several ferrocenyl conjugates. In these conjugates, the ferrocenyl moiety has played a vital role in enhancing or imparting the anticancer activity to the molecule. The ferrocenyl conjugates induce the cytotoxicity by generating reactive oxygen species and thereby damaging the DNA. In medicinal chemistry, the five membered nitrogen heterocycles (azoles) play a significant role due to their rigid ring structure and hydrogen bonding ability with the biomolecules. Several potent drug candidates with azole groups have been in use as chemotherapeutics. Considering the importance of ferrocenyl moiety and azole groups, several ferrocenyl azole conjugates have been synthesized and screened for their biological activities. Hence, in the view of a wide scope in the development of potent drugs based on ferrocenyl azole conjugates, herein we present the details of synthesis and the anticancer activities of ferrocenyl compounds bearing azole groups such as imidazole, triazoles, thiazole and isoxazoles.

The Anthraquinone Derivative C2 Enhances Oxaliplatin-Induced Cell Death and Triggers Autophagy via the PI3K/AKT/mTOR Pathway

Chemotherapy resistance in cancer is an essential factor leading to high mortality rates. Tumor multidrug resistance arises as a result of the autophagy process. Our previous study found that compound 1-nitro-2 acyl anthraquinone-leucine (C2) exhibited excellent anti-colorectal cancer (CRC) activity involving autophagy and apoptosis-related proteins, whereas its underlying mechanism remains unclear. A notable aspect of this study is how C2 overcomes the multidrug susceptibility of HCT116/L-OHP, a colon cancer cell line that is resistant to both in vitro and in vivo oxaliplatin (trans-/-diaminocyclohexane oxalatoplatinum; L-OHP). In a xenograft tumor mouse model, we discovered that the mixture of C2 and L-OHP reversed the resistance of HCT116/L-OHP cells to L-OHP and inhibited tumor growth; furthermore, C2 down-regulated the gene expression levels of P-gp and BCRP and decreased P-gp's drug efflux activity. It is important to note that while C2 re-sensitized the HCT116/L-OHP cells to L-OHP for apoptosis, it also triggered a protective autophagic pathway. The expression levels of cleaved caspase-3 and Beclin 1 steadily rose. Expression of PI3K, phosphorylated AKT, and mTOR were decreased, while p53 increased. We demonstrated that the anthraquinone derivative C2 acts as an L-OHP sensitizer and reverses resistance to L-OHP in HCT116/L-OHP cells. It suggests that C2 can induce autophagy in HCT116/L-OHP cells by mediating p53 and the PI3K/AKT/mTOR signaling pathway.

Insights into the computer-aided drug design and discovery based on anthraquinone scaffold for cancer treatment: A systematic review

BACKGROUND

In the search for better anticancer drugs, computer-aided drug design (CADD) techniques play an indispensable role in facilitating the lengthy and costly drug discovery process especially when natural products are involved. Anthraquinone is one of the most widely-recognized natural products with anticancer properties. This review aimed to systematically assess and synthesize evidence on the utilization of CADD techniques centered on the anthraquinone scaffold for cancer treatment.

METHODS

The conduct and reporting of this review were done in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) 2020 guideline. The protocol was registered in the "International prospective register of systematic reviews" database (PROSPERO: CRD42023432904) and also published recently. The search strategy was designed based on the combination of concept 1 "CADD or virtual screening", concept 2 "anthraquinone" and concept 3 "cancer". The search was executed in PubMed, Scopus, Web of Science and MedRxiv on 30 June 2023.

RESULTS

Databases searching retrieved a total of 317 records. After deduplication and applying the eligibility criteria, the final review ended up with 32 articles in which 3 articles were found by citation searching. The CADD methods used in the studies were either structure-based alone (69%) or combined with ligand-based methods via parallel (9%) or sequential (22%) approaches. Molecular docking was performed in all studies, with Glide and AutoDock being the most popular commercial and public software used respectively. Protein data bank was used in most studies to retrieve the crystal structure of the targets of interest while the main ligand databases were PubChem and Zinc. The utilization of in-silico techniques has enabled a deeper dive into the structural, biological and pharmacological properties of anthraquinone derivatives, revealing their remarkable anticancer properties in an all-rounded fashion.

CONCLUSION

By harnessing the power of computational tools and leveraging the natural diversity of anthraquinone compounds, researchers can expedite the development of better drugs to address the unmet medical needs in cancer treatment by improving the treatment outcome for cancer patients.

Aloe-Emodin Isolated from Rheum Undulatum L. Regulates Cell Cycle Distribution and Cellular Senescence in Human Prostate Cancer LNCaP Cells

Senescence can promote hyperplastic pathologies, such as cancer. Prostate cancer is the second most common type of cancer in men. The p21-mediate cellular senescence, facilitated through the tumor suppressor p53-dependent pathway, is considered the primary mechanism for cancer treatment. Aloe-emodin, has been reported to exert anticancer effects in various types of cancers. This study aimed to investigate the bioactivity of aloe-emodin in LNCaP cells via the activation of p21-mediated cellular senescence. Aloe-emodin treatment increased the percentage of cells in the G1 phase while decreasing the percentage in the S phase. This effect was reflected in the expression levels of proteins associated with cell cycle progression, such as p21CIP, retinoblastoma protein, and cyclin-dependent kinase2/4 in LNCaP cells. However, aloe-emodin-treated LNCaP cells did not induce cell cycle arrest at G2/M checkpoint. Moreover, increased senescence-associated-galactosidase activity was observed in a dose-dependent manner following treatment with aloe-emodin. Aloe-emodin also induced DNA damage by modulating the expression of histone H2AX and lamin B1. Furthermore, aloe-emodin inhibited the proliferation of LNCaP cells, contrasting with the exponential growth observed in the nontreated cells. Importantly, this inhibition did not impact the immune system, as evidenced by the increased proliferation of splenocytes isolated from mice. These findings provide preliminary evidence of the anticancer effect of aloe-emodin in LNCaP cells, necessitating further investigations into the underlying mechanisms in vivo and human subjects.

Dothideomins A-D, Antibacterial Polycyclic Bisanthraquinones from the Endophytic Fungus Dothideomycetes sp. BMC-101

Four new bisanthraquinones, dothideomins A-D (1-4), were identified from Dothideomycetes sp. BMC-101, an endophytic fungus isolated from Magnolia grandiflora L. leaves. Their chemical structures were established by NMR analysis, single-crystal X-ray crystallography, and ECD analysis. Dothideomins A-D (1-4) were characterized by an unusual 6/6/6/5/6/3/6/6 octocyclic scaffold (1 and 2) and a 6/6/6/5/6/6/6 heptacyclic scaffold (3 and 4), respectively. All compounds, especially 1 and 3, exhibited potent antibacterial activity with MIC values ranging from 0.4 to 0.8 μg/mL.

In Vitro, Molecular Docking and In Silico ADME/Tox Studies of Emodin and Chrysophanol against Human Colorectal and Cervical Carcinoma

Anthraquinones (AQs) are present in foods, dietary supplements, pharmaceuticals, and traditional treatments and have a wide spectrum of pharmacological activities. In the search for anti-cancer drugs, AQ derivatives are an important class. In this study, anthraquinone aglycons chrysophanol (Chr), emodin (EM) and FDA-approved anticancer drug fluorouracil were analyzed by molecular docking studies against receptor molecules caspase-3, apoptosis regulator Bcl-2, TRAF2 and NCK-interacting protein kinase (TNIK) and cyclin-dependent protein kinase 2 (CDK2) as novel candidates for future anticancer therapeutic development. The ADMET SAR database was used to predict the toxicity profile and pharmacokinetics of the Chr and EM. Furthermore, in silico results were validated by the in vitro anticancer activity against HCT-116 and HeLa cell lines to determine the anticancer effect. According to the docking studies simulated by the docking program AutoDock Vina 4.0, Chr and EM had good binding energies against the target proteins. It has been observed that Chr and EM show stronger molecular interaction than that of the FDA-approved anticancer drug fluorouracil. In the in vitro results, Chr and EM demonstrated promising anticancer activity in HCT-116 and HeLa cells. These findings lay the groundwork for the potential use of Chr and EM in the treatment of human colorectal and cervical carcinomas.

Click Chemistry Inspired Synthesis of Hydroxyanthracene Triazolyl Glycoconjugates

Novel hydroxyanthracene-based terminal alkynes 3 and 5a/b were synthesized by the acetylide addition reaction at the 9,10-position of anthraquinone 1 under mild conditions. The developed alkynes 3, 5a, and 5b on Huisgen azide-alkyne cycloaddition reaction with azido-sugars 6 in the presence of Cu(I) catalyst provided a series of triazole fasten hydroxyanthracene glycoconjugates 7, 8, and 9, respectively, in good yields. The representative compounds 9 and 7h were successfully deprotected under room-temperature conditions to liberate the corresponding free glycoconjugates 10 and 11, respectively. Further, structures of a few compounds were unmaliciously evidenced by their single-crystal X-ray.

Bis(chloroacetamidino)-Derived Heteroarene-Fused Anthraquinones Bind to and Cause Proteasomal Degradation of tNOX, Leading to c-Flip Downregulation and Apoptosis in Oral Cancer Cells

Simple Summary

New-generation anthraquinone derivatives attached with different heterocycles and bearing chloroacetamidines in the side chains have been synthesized to reduce side effects and drug resistance. In this study, we identified the cellular target of the studied compounds through ligand binding assays and in silico simulations. Our results illustrate that the studied compounds bound to and targeted the tumor-associated NADH oxidase (tNOX) in oral cancer cells. tNOX is a growth-related protein and is found to be expressed in cancer cells but not in non-transformed cells, and its knockdown by RNA interference in tumor cells overturns cancer phenotypes, supporting its role in cellular growth. We also identified that tNOX bound to the studied compounds and underwent degradation, which was correlated with apoptosis induction in oral cancer cells.

Abstract

Anthraquinone-based intercalating compounds, namely doxorubicin and mitoxantrone, have been used clinically based on their capacity to bind DNA and induce DNA damage. However, their applications have been limited by side effects and drug resistance. New-generation anthraquinone derivatives fused with different heterocycles have been chemically synthesized and screened for higher anticancer potency. Among the compounds reported in our previous study, 4,11-bis(2-(2-chloroacetamidine)ethylamino)anthra[2,3-b]thiophene-5,10-dione dihydrochloride (designated 2c) was found to be apoptotic, but the direct cellular target responsible for the cytotoxicity remained unknown. Here, we report the synthesis and anticancer properties of two other derivatives, 4,11-bis(2-(2-chloroacetamidine)ethylamino)naphtho[2,3-f]indole-5,10-dione dihydrochloride (2a) and 4,11-bis(2-(2-chloroacetamidine)ethylamino)-2-methylanthra[2,3-b]furan-5,10-dione dihydrochloride (2b). We sought to identify and validate the protein target(s) of these derivatives in oral cancer cells, using molecular docking simulations and cellular thermal shift assays (CETSA). Our CETSA results illustrate that these derivatives targeted the tumor-associated NADH oxidase (tNOX, ENOX2), and their direct binding downregulated tNOX in p53-functional SAS and p53-mutated HSC-3 cells. Interestingly, the compounds targeted and downregulated tNOX to reduce SIRT1 deacetylase activity and increase Ku70 acetylation, which triggers c-Flip ubiquitination and induces apoptosis in oral cancer cells. Together, our data highlight the potential value of these heteroarene-fused anthraquinones in managing cancer by targeting tNOX and augmenting apoptosis.

Emodin Sensitizes Cervical Cancer Cells to Vinblastine by Inducing Apoptosis and Mitotic Death

In recent years, studies on the effects of combining novel plant compounds with cytostatics used in cancer therapy have received considerable attention. Since emodin sensitizes tumor cells to chemotherapeutics, we evaluated changes in cervical cancer cells after its combination with the antimitotic drug vinblastine. Cellular changes were demonstrated using optical, fluorescence, confocal and electron microscopy. Cell viability was assessed by MTT assay. The level of apoptosis, caspase 3/7, Bcl-2 protein, ROS, mitochondrial membrane depolarization, cell cycle and degree of DNA damage were analyzed by flow cytometry. The microscopic image showed indicators characteristic for emodin- and vinblastine-induced mitotic catastrophe, i.e., multinucleated cells, giant cells, cells with micronuclei, and abnormal mitotic figures. These compounds also increased blocking of cells in the G2/M phase, and the generated ROS induced swelling and mitochondrial damage. This translated into the growth of apoptotic cells with active caspase 3/7 and inactivation of Bcl-2 protein and active ATM kinase. Emodin potentiated the cytotoxic effect of vinblastine, increasing oxidative stress, mitotic catastrophe and apoptosis. Preliminary studies show that the combined action of both compounds, may constitute an interesting form of anticancer therapy.

Effects of Anthraquinones on Immune Responses and Inflammatory Diseases

The anthraquinones (AQs) and derivatives are widely distributed in nature, including plants, fungi, and insects, with effects of anti-inflammation and anti-oxidation, antibacterial and antiviral, anti-osteoporosis, anti-tumor, etc. Inflammation, including acute and chronic, is a comprehensive response to foreign pathogens under a variety of physiological and pathological processes. AQs could attenuate symptoms and tissue damages through anti-inflammatory or immuno-modulatory effects. The review aims to provide a scientific summary of AQs on immune responses under different pathological conditions, such as digestive diseases, respiratory diseases, central nervous system diseases, etc. It is hoped that the present paper will provide ideas for future studies of the immuno-regulatory effect of AQs and the therapeutic potential for drug development and clinical use of AQs and derivatives.

A Co(III) Complex of 1-Amino-4-hydroxy-9,10-anthraquinone Exhibits Apoptotic Action against MCF-7 Human Breast Cancer Cells

A Co(III) complex of 1-amino-4-hydroxy-9,10-anthraquinone (QH) (Scheme-1) having the molecular formula CoQ₃ (Scheme-2) was prepared and characterized by elemental analysis, FTIR spectroscopy, UV-vis spectroscopy, fluorescence spectroscopy, and mass spectrometry. In the absence of a single crystal, the energy-optimized molecular structure of CoQ₃ was determined by employing computational methods that was validated using spectroscopic evidences, elemental analysis, and mass spectrometry data. The electrochemical properties of the complex were analyzed using cyclic voltammetry and indicate a substantial modification of the electrochemical properties of the parent amino-hydroxy-9,10-anthraquinone. CoQ₃ was thereafter tested on MCF-7 human breast cancer cells. The IC₅₀ value for a 24 h incubation was found to be (95 ± 0.05) μg/mL. The study showed that such cancer cells underwent both early and late apoptosis following the interaction with CoQ₃.

Photosensitization of a subcutaneous tumour by the natural anthraquinone parietin and blue light

Photodynamic therapy (PDT) is an anticancer treatment involving administration of a tumour-localizing photosensitizer, followed by activation by light of a suitable wavelength. In previous work, we showed that the natural anthraquinone (AQ) Parietin (PTN), was a promising photosensitizer for photodynamic therapy of leukemic cells in vitro. The present work aimed to analyze the photosensitizing ability of PTN in the mammary carcinoma LM2 cells in vitro and in vivo in a model of subcutaneously implanted tumours. Photodynamic therapy mediated by parietin (PTN-PDT) (PTN 30 µM, 1 h and 1.78 J/cm² of blue light) impaired cell growth and migration of LM2 cells in vitro. PTN per se induced a significant decrease in cell migration, and it was even more marked after illumination (migration index was 0.65 for PTN and 0.30 for PTN-PDT, *p < 0.0001, ANOVA test followed by Tukey's multiple comparisons test), suggesting that both PTN and PTN-PDT would be potential inhibitors of metastasis. Fluorescence microscopy observation indicated cytoplasmic localization of the AQ and no fluorescence at all was recorded in the nuclei. When PTN (1.96 mg) dissolved in dimethyl sulfoxide was topically applied on the skin of mice subcutaneously implanted with LM2 cells, PTN orange fluorescence was strongly noticed in the stratum corneum and also in the inner layers of the tumour up to approximately 5 mm. After illumination with 12.74 J/cm² of blue light, one PDT dose at day 1, induced a significant tumour growth delay at day 3, which was not maintained in time. Therefore, we administered a second PTN-PDT boost on day 3. Under these conditions, the delay of tumour growth was 28% both on days 3 and 4 of the experiment (*p < 0.05 control vs. PTN-PDT, two-way ANOVA, followed by Sidak's multiple comparisons test). Histology of tumours revealed massive tumour necrosis up to 4 mm of depth. Intriguingly, a superficial area of viable tumour in the 1 mm superficial area, and a quite conserved intact skin was evidenced. We hypothesize that this may be due to PTN aggregation in contact with the skin and tumour milieu of the most superficial tumour layers, thus avoiding its photochemical properties. On the other hand, normal skin treated with PTN-PDT exhibited slight histological changes. These preliminary findings encourage further studies of natural AQs administered in different vehicles, for topical treatment of cutaneous malignancies.

Journey of anthraquinones as anticancer agents - a systematic review of recent literature

Anthraquinones are privileged chemical scaffolds that have been used for centuries in various therapeutic applications. The anthraquinone moiety forms the core of various anticancer agents. However, the emergence of drug-resistant cancers warrants the development of new anticancer agents. The research endeavours towards new anthraquinone-based compounds are increasing rapidly in recent years. They are used as a core chemical template to achieve structural modifications, resulting in the development of new anthraquinone-based compounds as promising anticancer agents. Mechanistically, most of the anthraquinone-based compounds inhibit cancer progression by targeting essential cellular proteins. Herein, we review new anthraquinone analogues that have been developed in recent years as anticancer agents. This includes a systematic review of the recent literature (2005-2021) on anthraquinone-based compounds in cell-based models and key target proteins such as kinases, topoisomerases, telomerases, matrix metalloproteinases and G-quadruplexes involved in the viability of cancer cells. In addition to this, the developments in PEG-based delivery of anthraquinones and the toxicity aspects of anthraquinone derivatives are also discussed. The review dispenses a compact background knowledge to understanding anthraquinones for future research on the expansion of anticancer therapeutics.

Chemistry, Biosynthesis, Physicochemical and Biological Properties of Rubiadin: A Promising Natural Anthraquinone for New Drug Discovery and Development

Anthraquinones (AQs) are found in a variety of consumer products, including foods, nutritional supplements, drugs, and traditional medicines, and have a wide range of pharmacological actions. Rubiadin, a 1,3-dihydroxy-2-methyl anthraquinone, primarily originates from Rubia cordifolia Linn (Rubiaceae). It was first discovered in 1981 and has been reported for many biological activities. However, no review has been reported so far to create awareness about this molecule and its role in future drug discovery. Therefore, the present review aimed to provide comprehensive evidence of Rubiadin's phytochemistry, biosynthesis, physicochemical properties, biological properties and therapeutic potential. Relevant literature was gathered from numerous scientific databases including PubMed, ScienceDirect, Scopus and Google Scholar between 1981 and up-to-date. The distribution of Rubiadin in numerous medicinal plants, as well as its method of isolation, synthesis, characterisation, physiochemical properties and possible biosynthesis pathways, was extensively covered in this review. Following a rigorous screening and tabulating, a thorough description of Rubiadin's biological properties was gathered, which were based on scientific evidences. Rubiadin fits all five of Lipinski's rule for drug-likeness properties. Then, the in depth physiochemical characteristics of Rubiadin were investigated. The simple technique for Rubiadin's isolation from R. cordifolia and the procedure of synthesis was described. Rubiadin is also biosynthesized via the polyketide and chorismate/o-succinylbenzoic acid pathways. Rubiadin is a powerful molecule with anticancer, antiosteoporotic, hepatoprotective, neuroprotective, anti-inflammatory, antidiabetic, antioxidant, antibacterial, antimalarial, antifungal, and antiviral properties. The mechanism of action for the majority of the pharmacological actions reported, however, is unknown. In addition to this review, an in silico molecular docking study was performed against proteins with PDB IDs: 3AOX, 6OLX, 6OSP, and 6SDC to support the anticancer properties of Rubiadin. The toxicity profile, pharmacokinetics and possible structural modifications were also described. Rubiadin was also proven to have the highest binding affinity to the targeted proteins in an in silico study; thus, we believe it may be a potential anticancer molecule. In order to present Rubiadin as a novel candidate for future therapeutic development, advanced studies on preclinical, clinical trials, bioavailability, permeability and administration of safe doses are necessary.

Repurposing drugs as novel triple negative breast cancer therapeutics

BACKGROUND

Among all the types of breast cancer (BC), triple negative breast cancer (TNBC) is the most aggressive form having high metastasis and recurrence rate with limited treatment options. Conventional treatments such as chemotherapy and radiotherapy have lots of toxic side effects and also no FDA approved therapies are available till now. Repurposing of old clinically approved drugs towards various targets of TNBC is the new approach with lesser side effects and also leads to successful inexpensive drug development with less time consuming. Medicinal plants containg various phytoconstituents (flavonoids, alkaloids, phenols, essential oils, tanins, glycosides, lactones) plays very crucial role in combating various types of diseases and used in drug development process because of having lesser side effects.

OBJECTIVE

The present review focuses in summarization of various categories of repurposed drugs against multitarget of TNBC and also summarizes the phytochemical categories that targets TNBC singly or in combination with synthetic old drugs.

METHODS

Literature information was collected from various databases such as Pubmed, Web of Science, Scopus and Medline to understand and clarify the role and mechanism of repurposed synthetic drugs and phytoconstituents aginst TNBC by using keywords like "breast cancer", "repurposed drugs", "TNBC" and "phytoconstituents".

RESULTS

Various repurposed drugs and phytochemicals targeting different signaling pathways that exerts their cytotoxic activities on TNBC cells ultimately leads to apoptosis of cells and also lowers the recurrence rate and stops the metastasis process.

CONCLUSION

Inhibitory effects seen in different levels, which provides information and evidences to researchers towards drug developments process and thus further more investigations and researches need to be taken to get the better therapeutic treatment options against TNBC.

Plant-Mediated Zinc Oxide Nanoparticles: Advances in the New Millennium towards Understanding Their Therapeutic Role in Biomedical Applications

Zinc oxide nanoparticles have become one of the most popular metal oxide nanoparticles and recently emerged as a promising potential candidate in the fields of optical, electrical, food packaging, and biomedical applications due to their biocompatibility, low toxicity, and low cost. They have a role in cell apoptosis, as they trigger excessive reactive oxygen species (ROS) formation and release zinc ions (Zn2+) that induce cell death. The zinc oxide nanoparticles synthesized using the plant extracts appear to be simple, safer, sustainable, and more environmentally friendly compared to the physical and chemical routes. These biosynthesized nanoparticles possess strong biological activities and are in use for various biological applications in several industries. Initially, the present review discusses the synthesis and recent advances of zinc oxide nanoparticles from plant sources (such as leaves, stems, bark, roots, rhizomes, fruits, flowers, and seeds) and their biomedical applications (such as antimicrobial, antioxidant, antidiabetic, anticancer, anti-inflammatory, photocatalytic, wound healing, and drug delivery), followed by their mechanisms of action involved in detail. This review also covers the drug delivery application of plant-mediated zinc oxide nanoparticles, focusing on the drug-loading mechanism, stimuli-responsive controlled release, and therapeutic effect. Finally, the future direction of these synthesized zinc oxide nanoparticles' research and applications are discussed.

Anthraquinones as Inhibitors of SOS RAS-GEF Activity

Recent breakthroughs have reignited interest in RAS GEFs as direct therapeutic targets. To search for new inhibitors of SOS GEF activity, a repository of known/approved compounds (NIH-NACTS) and a library of new marine compounds (Biomar Microbial Technologies) were screened by means of in vitro RAS-GEF assays using purified, bacterially expressed SOS and RAS constructs. Interestingly, all inhibitors identified in our screenings (two per library) shared related chemical structures belonging to the anthraquinone family of compounds. All our anthraquinone SOS inhibitors were active against the three canonical RAS isoforms when tested in our SOS GEF assays, inhibited RAS activation in mouse embryonic fibroblasts, and were also able to inhibit the growth of different cancer cell lines harboring WT or mutant RAS genes. In contrast to the commercially available anthraquinone inhibitors, our new marine anthraquinone inhibitors did not show in vivo cardiotoxicity, thus providing a lead for future discovery of stronger, clinically useful anthraquinone SOS GEF blockers.

Marine Anthraquinones: Pharmacological and Toxicological Issues

The marine ecosystem, populated by a myriad of animals, plants, and microorganisms, is an inexhaustible reservoir of pharmacologically active molecules. Among the multiple secondary metabolites produced by marine sources, there are anthraquinones and their derivatives. Besides being mainly known to be produced by terrestrial species, even marine organisms and the uncountable kingdom of marine microorganisms biosynthesize anthraquinones. Anthraquinones possess many different biological activities, including a remarkable antitumor activity. However, due to their peculiar chemical structures, anthraquinones are often associated with toxicological issues, even relevant, such as genotoxicity and mutagenicity. The aim of this review is to critically describe the anticancer potential of anthraquinones derived from marine sources and their genotoxic and mutagenic potential. Marine-derived anthraquinones show a promising anticancer potential, although clinical studies are missing. Additionally, an in-depth investigation of their toxicological profile is needed before advocating anthraquinones as a therapeutic armamentarium in the oncological area.

Molecular encapsulation of berberine and ethidium bromide in anthraquinonecarboxamido-β-cyclodextrin conjugate: supramolecular association with DNA duplex and G-quadruplexes

G-quadruplex DNA in recognized as a potential target for anti-cancer drugs. In this work, an anthraquinonecarboxamido derivative of β-cyclodextrin (AQCC) is synthesized as a novel DNA binder that further can deliver an additional molecule at the target, carrying it in the cavity of modified cyclodextrin. The binding of AQCC with ethidium bromide (EtBr), berberine (Ber), duplex calf-thymus DNA (CT-DNA), quadruplexes (G4) viz., kit22, myc22, and telo24 are studied. The compound acts as a host molecule for the encapsulation of DNA binders viz., EtBr, Ber and enhances their fluorescence due to the encapsulation in its AQCC's cyclodextrin cavity. The binding constant of the host: guest complex of EtBr and Ber with AQCC's cavity are 6.4 × 105 and 3.3 × 106 mol-1 dm3, respectively. The proximity of the protons of the guest and host molecules is confirmed by two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY). The conjugate displays a quenching of fluorescence selectively on the association with CT-DNA and quadruplex kit22 that is contrast to the spectral behavior with quadruplex myc22 and telo24. CT-DNA exhibits dissimilar fluorescence spectra in free- and EtBr-bound forms. In addition, kit22 exhibit dissimilar emission profile when AQCC encapsulates Ber. Therefore, the Ber-loaded complexes and the AQCC molecule bind to different G-quadruplexes with different binding strengths. In addition, the effect of Ber in binding to the target DNAs is pronounces since the Ber molecule has more affinity to bind to quadruplexes than the duplex.

Green synthesis of zinc oxide nanoparticles using leaf extracts of Raphanus sativus var. Longipinnatus and evaluation of their anticancer property in A549 cell lines

In 21 st century, nanomedicine has turned out to be an emergent modulus operation for the diagnosis and treatment for cancer. The current study includes the Green synthesis of zinc oxide nanoparticles (ZnO NPs) from the leaves of Raphanus sativus var. Longipinnatus and interpretation of its anticancer activity. Synthesized ZnO NPs were investigated by UV-vis, FTIR, particle size analysis, SEM, XRD and its anticancer activity using A549 cell lines. The UV-vis and particle size confirmed the developed ZnO NPs are in nanoscale. The FTIR studies confirmed the presence of various functional groups. SEM and XRD pictures confirmed the partial crystal spherical shape and wurtzite crystal nature. The cytotoxicity results pointed out the enhanced cytotoxic effect of the synthesized ZnO NPs. This is the first attempt of Raphanus sativus var. Longipinnatus facilitated synthesis of ZnO NPs as anticancer agents and may subsequently be potential chemopreventive agent against other cancer treatment in future.