Eugenol potentiates cisplatin anti-cancer activity through inhibition of ALDH-positive breast cancer stem cells and the NF-κB signaling pathway

Novel Anti-Cancer Stem Cell Compounds: A Comprehensive Review

Cancer stem cells (CSCs) possess a significant ability to renew themselves, which gives them a strong capacity to form tumors and expand to encompass additional body areas. In addition, they possess inherent resistance to chemotherapy and radiation therapies used to treat many forms of cancer. Scientists have focused on investigating the signaling pathways that are highly linked to the ability of CSCs to renew themselves and maintain their stem cell properties. The pathways encompassed are Notch, Wnt/β-catenin, hedgehog, STAT3, NF-κB, PI-3K/Akt/mTOR, sirtuin, ALDH, MDM2, and ROS. Recent studies indicate that directing efforts towards CSC cells is essential in eradicating the overall cancer cell population and reducing the likelihood of tumor metastasis. As our comprehension of the mechanisms that stimulate CSC activity, growth, and resistance to chemotherapy advances, the discovery of therapeutic drugs specifically targeting CSCs, such as small-molecule compounds, holds the potential to revolutionize cancer therapy. This review article examines and analyzes the novel anti-CSC compounds that have demonstrated effective and selective targeting of pathways associated with the renewal and stemness of CSCs. We also discussed their special drug metabolism and absorption mechanisms. CSCs have been the subject of much study in cancer biology. As a possible treatment for malignancies, small-molecule drugs that target CSCs are gaining more and more attention. This article provides a comprehensive review of the current state of key small-molecule compounds, summarizes their recent developments, and anticipates the future discovery of even more potent and targeted compounds, opening up new avenues for cancer treatment.

In vitro antiviral activity of eugenol on Singapore grouper iridovirus

The high mortality rate of Singapore grouper iridovirus (SGIV) posing a serious threat to the grouper aquaculture industry and causing significant economic losses. Therefore, finding effective drugs against SGIV is of great significance. Eugenol (C10H12O2) is a phenolic aromatic compound, has been widely studied for its anti-inflammatory, antioxidant and antiviral capacity. In this study, we explored the effect of eugenol on SGIV infection and its possible mechanisms using grouper spleen cells (GS) as an in vitro model. We found that treatment of GS cells with 100 μM eugenol for 4 h exhibited the optimal inhibitory effect on SGIV. Eugenol was able to reduce the expression level of inflammatory factors by inhibiting the activation of MAPK pathway and also inhibited the activity of NF-κB and AP-1 promoter. On the other hand, eugenol attenuated cellular oxidative stress by reducing intracellular ROS and promoted the expression of interferon-related genes. Therefore, we conclude that eugenol inhibits SGIV infection by enhancing cellular immunity through its anti-inflammatory and antioxidant functions.

Benzimidazole scaffold as a potent anticancer agent with different mechanisms of action (2016-2023)

Benzimidazole scaffolds have potent anticancer activity due to their structure similarity to nucleoside. In addition, benzimidazoles could function as hydrogen donors or acceptors and bind to different drug targets that participate in cancer progression. The literature had many anticancer agents containing benzimidazole cores that gained much interest. Provoked by our endless interest in benzimidazoles as anticancer agents, we summarized the successful trials of the benzimidazole scaffolds in this concern. Moreover, we discuss the substantial opportunities in cancer treatment using benzimidazole-based drugs that may direct medicinal chemists for a compelling future design of more active chemotherapeutic agents with potential clinical applications. The uniqueness of this work lies in the highlighted benzimidazole scaffold hybridization with different molecules and benzimidazole-metal complexes, detailed mechanisms of action, and the IC50 of the developed compounds determined by different laboratories after 2015.

Eugenol as a potential adjuvant therapy for gingival squamous cell carcinoma

Adoption of plant-derived compounds for the management of oral cancer is encouraged by the scientific community due to emerging chemoresistance and conventional treatments adverse effects. Considering that very few studies investigated eugenol clinical relevance for gingival carcinoma, we ought to explore its selectivity and performance according to aggressiveness level. For this purpose, non-oncogenic human oral epithelial cells (GMSM-K) were used together with the Tongue (SCC-9) and Gingival (Ca9-22) squamous cell carcinoma lines to assess key tumorigenesis processes. Overall, eugenol inhibited cell proliferation and colony formation while inducing cytotoxicity in cancer cells as compared to normal counterparts. The recorded effect was greater in gingival carcinoma and appears to be mediated through apoptosis induction and promotion of p21/p27/cyclin D1 modulation and subsequent Ca9-22 cell cycle arrest at the G0/G1 phase, in a p53-independent manner. At these levels, distinct genetic profiles were uncovered for both cell lines by QPCR array. Moreover, it seems that our active component limited Ca9-22 and SCC-9 cell migration respectively through MMP1/3 downregulation and stimulation of inactive MMPs complex formation. Finally, Ca9-22 behaviour appears to be mainly modulated by the P38/STAT5/NFkB pathways. In summary, we can disclose that eugenol is cancer selective and that its mediated anti-cancer mechanisms vary according to the cell line with gingival squamous cell carcinoma being more sensitive to this phytotherapy agent.

Ovarian tumor cell-derived JAGGED2 promotes omental metastasis through stimulating the Notch signaling pathway in the mesothelial cells

The primary site of metastasis for epithelial ovarian cancer (EOC) is the peritoneum, and it occurs through a multistep process that begins with adhesive contacts between cancer cells and mesothelial cells. Despite evidence that Notch signaling has a role in ovarian cancer, it is unclear how exactly it contributes to ovarian cancer omental metastasis, as well as the cellular dynamics and intrinsic pathways that drive this tropism. Here we show that tumor cells produced the Notch ligand Jagged2 is a clinically and functionally critical mediator of ovarian cancer omental metastasis by activating the Notch signaling in single-layered omental mesothelial cells. In turn, Jagged2 promotes tumor growth and therapeutic resistance by stimulating IL-6 release from mesothelial cells. Additionally, Jagged2 is a potent downstream mediator of the omental metastasis cytokine TGF-β that is released during omental destruction. Importantly, therapeutic inhibition of Jagged2-mediated omental metastasis was significantly improved by directly disrupting the Notch pathway in omental mesothelial cells. These findings highlight the key role of Jagged2 to the functional interplay between the TGF-β and the Notch signaling pathways during the metastatic process of ovarian cancer cells to the omentum and identify the Notch signaling molecule as a precision therapeutic target for ovarian cancer metastasis.

Pharmacodynamic, pharmacokinetic, toxicity, and recent advances in Eugenol's potential benefits against natural and chemical noxious agents: A mechanistic review

The active biological phytochemicals, crucial compounds employed in creating hundreds of medications, are derived from valuable and medicinally significant plants. These phytochemicals offer excellent protection from various illnesses, including inflammatory disorders and chronic conditions caused by oxidative stress. A phenolic monoterpenoid known as eugenol (EUG), it is typically found in the essential oils of many plant species from the Myristicaceae, Myrtaceae, Lamiaceae, and Lauraceae families. One of the main ingredients of clove oil (Syzygium aromaticum (L.), Myrtaceae), it has several applications in industry, including flavoring food, pharmaceutics, dentistry, agriculture, and cosmeceuticals. Due to its excellent potential for avoiding many chronic illnesses, it has lately attracted attention. EUG has been classified as a nonmutant, generally acknowledged as a safe (GRAS) chemical by the World Health Organization (WHO). According to the existing research, EUG possesses notable anti-inflammatory, antioxidant, analgesic, antibacterial, antispasmodic, and apoptosis-promoting properties, which have lately gained attention for its ability to control chronic inflammation, oxidative stress, and mitochondrial malfunction and dramatically impact human wellness. The purpose of this review is to evaluate the scientific evidence from the most significant research studies that have been published regarding the protective role and detoxifying effects of EUG against a wide range of toxins, including biological and chemical toxins, as well as different drugs and pesticides that produce a variety of toxicities, throughout view of the possible advantages of EUG.

Eugenol: In Vitro and In Ovo Assessment to Explore Cytotoxic Effects on Osteosarcoma and Oropharyngeal Cancer Cells

Cancer is a significant health problem worldwide; consequently, new therapeutic alternatives are being investigated, including those found in the vegetable kingdom. Eugenol (Eug) has attracted attention for its therapeutic properties, especially in stomatology. The purpose of this study was to investigate the cytotoxicity of Eug, in vitro, on osteosarcoma (SAOS-2) and oropharyngeal squamous cancer (Detroit-562) cells, as well as its potential irritant effect in ovo at the level of the chorioallantoic membrane (CAM). The data obtained following a 72 h Eug treatment highlighted the reduction in cell viability up to 41% in SAOS-2 cells and up to 37% in Detroit-562 cells, respectively. The apoptotic-like effect of Eug was indicated by the changes in cell morphology and nuclear aspect; the increase in caspase-3/7, -8 and -9 activity; the elevated expression of Bax and Bad genes; and the increase in luminescence signal (indicating phosphatidylserine externalization) that preceded the increase in fluorescence signal (indicating the compromise of membrane integrity). Regarding the vascular effects, slight signs of coagulation and vascular lysis were observed, with an irritation score of 1.69 for Eug 1 mM. Based on these results, the efficiency of Eug in cancer treatment is yet to be clarified.

Therapeutic activity of eugenol towards mitigation of anaemia and oxidative organ damage caused by Plasmodium berghei

The parasite responsible for causing malaria infection, Plasmodium, is known to exhibit resistance to a number of already available treatments. This has prompted the continue search for new antimalarial drugs ranging from medicinal plant parts to synthetic compounds. In lieu of this, the mitigative action of the bioactive compound, eugenol towards P. berghei-induced anaemia and oxidative organ damage was investigated following a demonstration of in vitro and in vivo antiplasmodial effects. Mice were infected with chloroquine-sensitive strain of P. berghei and thereafter treated with eugenol at doses of 10 and 20 mg/kg body weight (BW) for seven days. The packed cell volume and redox sensitive biomarkers in the liver, brain and spleen were measured. Our result demonstrated that eugenol significantly (p < 0.05) ameliorated the P. berghei-associated anaemia at a dose of 10 mg/kg BW. In addition, the compound, at a dose of 10 mg/kg BW, significantly (p < 0.05) alleviated the P. berghei-induced organ damage. This evidently confirmed that eugenol plays an ameliorative role towards P. berghei-related pathological alterations. Hence, the study opens up a new therapeutic use of eugenol against plasmodium parasite.

Exploring the Potent Anticancer Activity of Essential Oils and Their Bioactive Compounds: Mechanisms and Prospects for Future Cancer Therapy

Cancer is one of the leading causes of death worldwide, affecting millions of people each year. Fortunately, the last decades have been marked by considerable advances in the field of cancer therapy. Researchers have discovered many natural substances, some of which are isolated from plants that have promising anti-tumor activity. Among these, essential oils (EOs) and their constituents have been widely studied and shown potent anticancer activities, both in vitro and in vivo. However, despite the promising results, the precise mechanisms of action of EOs and their bioactive compounds are still poorly understood. Further research is needed to better understand these mechanisms, as well as their effectiveness and safety in use. Furthermore, the use of EOs as anticancer drugs is complex, as it requires absolute pharmacodynamic specificity and selectivity, as well as an appropriate formulation for effective administration. In this study, we present a synthesis of recent work on the mechanisms of anticancer action of EOs and their bioactive compounds, examining the results of various in vitro and in vivo studies. We also review future research prospects in this exciting field, as well as potential implications for the development of new cancer drugs.

Signaling pathways governing the maintenance of breast cancer stem cells and their therapeutic implications

Breast cancer stem cells (BCSCs) represent a distinct subpopulation of cells with the ability to self-renewal and differentiate into phenotypically diverse tumor cells. The involvement of CSC in treatment resistance and cancer recurrence has been well established. Numerous studies have provided compelling evidence that the self-renewal ability of cancer stem cells is tightly regulated by specific signaling pathways, which exert critical roles to maintain an undifferentiated phenotype and prevent the differentiation of CSCs. Signaling pathways such as Wnt/β-catenin, NF-κB, Notch, Hedgehog, TGF-β, and Hippo have been implicated in the promotion of self-renewal of many normal and cancer stem cells. Given the pivotal role of BCSCs in driving breast cancer aggressiveness, targeting self-renewal signaling pathways holds promise as a viable therapeutic strategy for combating this disease. In this review, we will discuss the main signaling pathways involved in the maintenance of the self-renewal ability of BCSC, while also highlighting current strategies employed to disrupt the signaling molecules associated with stemness.

Synergistic Effects of New Curcumin Analog (PAC) and Cisplatin on Oral Cancer Therapy

Oral cancer has traditionally been treated with surgery, radiotherapy, chemotherapy, or a combination of these therapies. Although cisplatin, a chemotherapy drug, can effectively kill oral cancer cells by forming DNA adducts, its clinical use is limited due to adverse effects and chemo-resistance. Therefore, there is a need to develop new, targeted anticancer drugs to complement chemotherapy, allowing for reduced cisplatin doses and minimizing adverse effects. Recent studies have shown that 3,5-Bis (4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidine (PAC), a new curcumin analog, possesses anticancer properties and could be considered a complementary or alternative therapy. In this study, we aimed to assess the potential complementary effects of PAC in combination with cisplatin for treating oral cancer. We conducted experiments using oral cancer cell lines (Ca9-22) treated with different concentrations of cisplatin (ranging from 0.1 μM to 1 μM), either alone or in conjunction with PAC (2.5 and 5 μM). Cell growth was measured using the MTT assay, while cell cytotoxicity was evaluated using an LDH assay. Propidium iodide and annexin V staining were employed to examine the impact on cell apoptosis. Flow cytometry was used to investigate the effects of the PAC/cisplatin combination on cancer cell autophagy, oxidative stress, and DNA damage. Additionally, a Western Blot analysis was performed to assess the influence of this combination on pro-carcinogenic proteins involved in various signaling pathways. The results demonstrated that PAC enhanced the efficacy of cisplatin in a dose-dependent manner, leading to a significant inhibition of oral cancer cell proliferation. Importantly, treatment with PAC (5 μM) alongside different concentrations of cisplatin reduced the IC50 of cisplatin tenfold. Combining these two agents increased apoptosis by further inducing caspase activity. In addition, the concomitant use of PAC and cisplatin enhances oral cancer cell autophagy, ROS, and MitoSOX production. However, combined PAC with cisplatin inhibits the mitochondrial membrane potential (ΔΨm), which is a marker for cell viability. Finally, this combination further enhances the inhibition of oral cancer cell migration via the inhibition of epithelial-to-mesenchymal transition genes, such as E-cadherin. We demonstrated that the combination of PAC and cisplatin markedly enhanced oral cancer cell death by inducing apoptosis, autophagy, and oxidative stress. The data presented indicate that PAC has the potential to serve as a powerful complementary agent to cisplatin in the treatment of gingival squamous cell carcinomas.

Targeting aldehyde dehydrogenase enzymes in combination with chemotherapy and immunotherapy: An approach to tackle resistance in cancer cells

Modern cancer chemotherapy originated in the 1940s, and since then, many chemotherapeutic agents have been developed. However, most of these agents show limited response in patients due to innate and acquired resistance to therapy, which leads to the development of multi-drug resistance to different treatment modalities, leading to cancer recurrence and, eventually, patient death. One of the crucial players in inducing chemotherapy resistance is the aldehyde dehydrogenase (ALDH) enzyme. ALDH is overexpressed in chemotherapy-resistant cancer cells, which detoxifies the generated toxic aldehydes from chemotherapy, preventing the formation of reactive oxygen species and, thus, inhibiting the induction of oxidative stress and the stimulation of DNA damage and cell death. This review discusses the mechanisms of chemotherapy resistance in cancer cells promoted by ALDH. In addition, we provide detailed insight into the role of ALDH in cancer stemness, metastasis, metabolism, and cell death. Several studies investigated targeting ALDH in combination with other treatments as a potential therapeutic regimen to overcome resistance. We also highlight novel approaches in ALDH inhibition, including the potential synergistic employment of ALDH inhibitors in combination with chemotherapy or immunotherapy against different cancers, including head and neck, colorectal, breast, lung, and liver.

Enhancing Anti-Tumorigenic Efficacy of Eugenol in Human Colon Cancer Cells Using Enzyme-Responsive Nanoparticles

This study is focused on the selective delivery and release of the plant-based anticancer compound eugenol (EUG) in colorectal cancer cells (CRC). EUG is an apoptotic and anti-growth compound in diverse malignant tumors, including CRC. However, EUG's rapid metabolization, excretion, and side effects on normal cells at higher dosages are major limitations of its therapeutic potential. To address this problem, we developed a "smart" enzyme-responsive nanoparticle (eNP) loaded with EUG that exposes tumors to a high level of the drug while keeping its concentration low among healthy cells. We demonstrated that EUG induces apoptosis in CRC cells irrespective of their grades in a dose- and time-dependent manner. EUG significantly decreases cancer cell migration, invasion, and the population of colon cancer stem cells, which are key players in tumor metastasis and drug resistance. The "smart" eNPs-EUG show a high affinity to cancer cells with rapid internalization with no affinity toward normal colon epithelial cells. NPs-EUG enhanced the therapeutic efficacy of EUG measured by a cell viability assay and showed no toxicity effect on normal cells. The development of eNPs-EUG is a promising strategy for innovative anti-metastatic therapeutics.

Combination of Conventional Drugs with Biocompounds Derived from Cinnamic Acid: A Promising Option for Breast Cancer Therapy

Despite the options available for breast cancer (BC) therapy, several adverse effects and resistance limit the success of the treatment. Furthermore, the use of a single drug is associated with a high failure rate. We investigated through a systematic review the in vitro effects of the combination between conventional drugs and bioactive compounds derived from cinnamic acid in BC treatment. The information was acquired from the following databases: PubMed, Web of Science, Embase, Scopus, Lilacs and Cochrane library. We focused on "Cinnamates", "Drug Combinations" and "Breast neoplasms" for publications dating between January 2012 and December 2022, based on the PRISMA statement. The references of the articles were carefully reviewed. Finally, nine eligible studies were included. The majority of these studies were performed using MCF-7, MDA-MB-231, MDA-MB-468 and BT-20 cell lines and the combination between cisplatin, paclitaxel, doxorubicin, tamoxifen, dactolisib and veliparib, with caffeic acid phenethyl ester, eugenol, 3-caffeoylquinic acid, salvianolic acid A, ferulic acid, caffeic acid, rosmarinic acid and ursolic acid. The combination improved overall conventional drug effects, with increased cytotoxicity, antimigratory effect and reversing resistance. Combining conventional drugs with bioactive compounds derived from cinnamic acid could emerge as a privileged scaffold for establishing new treatment options for different BC types.

Eugenol modulates the NOD1-NF-κB signaling pathway via targeting NF-κB protein in triple-negative breast cancer cells

BACKGROUND

The most aggressive subtype of breast cancer, triple-negative breast cancer (TNBC), has a worse prognosis and a higher probability of relapse since there is a narrow range of treatment options. Identifying and testing potential therapeutic targets for the treatment of TNBC is of high priority.

METHODS

Using a transcriptional signature of triple-negative breast cancer collected from Gene Expression Omnibus (GEO), CMap was utilized to reposition compounds for the treatment of TNBC. CCK8 and colony formation experiments were performed to detect the effect of the candidate drug on the proliferation of TNBC cells. Meanwhile, transwell and wound healing assay were implemented to detect cell metastasis change caused by the candidate drug. Moreover, the proteomic approach was presently ongoing to evaluate the underlying mechanism of the candidate drug in TNBC. Furthermore, drug affinity responsive target stability (DARTS) coupled with LC-MS/MS was carried out to explore the potential drug target candidate in TNBC cells.

RESULTS

We found that the most widely used medication, eugenol, reduced the growth and metastasis of TNBC cells. According to the underlying mechanism revealed by proteomics, eugenol could inhibit TNBC cell proliferation and metastasis via the NOD1-NF-κB signaling pathway. DARTS experiment further revealed that eugenol may bind to NF-κB in TNBC cells.

CONCLUDES

Our findings pointed out that eugenol was a potential candidate drug for the treatment of TNBC.

Role of Medicinal plant-derived Nutraceuticals as a potential target for the treatment of breast cancer

Breast cancer (BC) is one of the most challenging cancers to treat, accounting for many cancer-related deaths. Over some years, chemotherapy, hormone treatment, radiation, and surgeries have been used to treat cancer. Unfortunately, these treatment options are unsuccessful due to crucial adverse reactions and multidrug tolerance/resistance. Although it is clear that substances in the nutraceuticals category have a lot of anti-cancer activity, using a supplementary therapy strategy, in this case, could be very beneficial. Nutraceuticals are therapeutic agents, which are nutrients that have drug-like characteristics and can be used to treat diseases. Plant nutraceuticals categorized into polyphenols, terpenoids, vitamins, alkaloids, and flavonoids are part of health food products, that have great potential for combating BC. Nutraceuticals can reduce BC's severity, limit malignant cell growth, and modify cancer-related mechanisms. Nutraceuticals acting by attenuating Hedgehog, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Notch, and Wnt/β-catenin signaling are the main pathways in controlling the self-renewal of breast cancer stem cells (BCSCs). This article reviews some important nutraceuticals and their modes of action, which can be very powerful versus BC. PRACTICAL APPLICATIONS: Nutraceuticals' importance to the control and diagnosis of breast cancer is undeniable and cannot be overlooked. Natural dietary compounds have a wide range of uses and have been used in traditional medicine. In addition, these natural chemicals can enhance the effectiveness of other traditional medicines. They may also be used as a treatment process independently because of their capacity to affect several cancer pathways. This study highlights a variety of natural chemicals, and their mechanisms of action, routes, synergistic effects, and future potentials are all examined.

A comprehensive and systematic review on potential anticancer activities of eugenol: From pre-clinical evidence to molecular mechanisms of action

BACKGROUND

Eugenol (1-allyl-4-hydroxy-3-methoxybenzene) is an important simple phenolic compound mainly derived from Syzygium aromaticum and many other plants. It is traditionally used in ayurveda and aromatherapy for the healing of many health problems. It also has significant applications in dentistry, agriculture, and flavour industry. This simple phenol has an eclectic range of pharmacological properties, such as antioxidant, anti-inflammatory, and anticancer activities. It is regarded as safe by the Food and Agricultural Organization of the United Nations due to its non-carcinogenic and non-mutagenic properties.

PURPOSE

The aim of this comprehensive review is to present a critical and systematic assessment of the antitumor ability of eugenol and its associated molecular targets in various cancers.

METHODS

It was carried out following the preferred reporting items for systematic reviews and meta-analysis guidelines. Risk of bias assessment was performed using the SYstematic review centre for laboratory animal experimentation guidelines. The literature search was performed in standard databases such as Science Direct, PubMed, Google Scholar, Scopus, and Web of Science using the keywords 'eugenol' or 'eugenol essential oil' and 'anti-cancer properties of eugenol'.

RESULTS

The scientific information from fifty-three studies was encompassed in the present review work. Eugenol exhibits significant anticancer effects in a variety of biological pathways, namely apoptosis, autophagy, cell cycle progression, inflammation, invasion, and metastasis. Eugenol-induced apoptosis has been noticed in osteosarcoma, skin tumors, melanoma, leukemia, gastric and mast cells. It decreases the expression of cyclin D1, cyclin B, proliferating cell nuclear antigen, nuclear factor-ƙB, inhibitor of nuclear factor ƙB, and B-cell lymphoma-2. Eugenol increases the expression of B-cell lymphoma-2 (BCL-2) associated X, BH3-interacting domain death agonist, BCL-2 associated agonist of cell death, apoptotic protease activating factor 1, cytochrome c, p21, and p53.

CONCLUSION

The anticancer potential exhibited by eugenol is mainly attributed to its anti-metastatic, anti-proliferative, anti-angiogenic, anti-inflammatory, cell cycle arrest, apoptotic, and autophagic effects. Hence, the use of eugenol alone or along with other chemotherapeutic anticancer agents is found to be very effective in cancer therapy.

Eugenol improves high-fat diet/streptomycin-induced type 2 diabetes mellitus (T2DM) mice muscle dysfunction by alleviating inflammation and increasing muscle glucose uptake

Eugenol has been used in dietary interventions for metabolic diseases such as diabetes and obesity. However, the protective effect of eugenol on muscle function in diabetes is unclear. In this study, a high-fat diet (HFD) with a streptozocin (STZ) injection induced type II diabetes mellitus in a mouse model. Oral eugenol lowered blood glucose and insulin resistance of HFD/STZ-treated mice. Eugenol reduced HFD/STZ-induced muscle inflammation and prevented muscle weakness and atrophy. Eugenol administration significantly increased GLUT4 translocation and AMPK phosphorylation in skeletal muscle, thereby enhancing glucose uptake. By silencing the transient receptor potential vanilloid channel 1 (TRPV1) gene in C2C12 myotube cells, eugenol was found to increase intracellular Ca2+ levels through TRPV1, which then activated calmodulin-dependent protein kinase-2 (CaMKK2) and affected AMPK protein phosphorylation. In conclusion, eugenol is a potential nutraceutical for preventing high-glucose-induced muscle impairments, which could be explained by its mediating effects on glucose absorption and inflammatory responses in the muscle.

Molecular Mechanisms of Action of Eugenol in Cancer: Recent Trends and Advancement

BACKGROUND

Cancer is, at present, among the leading causes of morbidity globally. Despite advances in treatment regimens for cancer, patients suffer from poor prognoses. In this context, the availability of vast natural resources seems to alleviate the shortcomings of cancer chemotherapy. The last decade has seen a breakthrough in the investigations related to the anticancer potential of dietary phytoconstituents. Interestingly, a handsome number of bioactive principles, ranging from phenolic acids, phenylpropanoids, flavonoids, stilbenes, and terpenoids to organosulphur compounds have been screened for their anticancer properties. Among the phenylpropanoids currently under clinical studies for anticancer activity, eugenol is a promising candidate. Eugenol is effective against cancers like breast, cervical, lung, prostate, melanomas, leukemias, osteosarcomas, gliomas, etc., as evident from preclinical investigations.

OBJECTIVE

The review aims to focus on cellular and molecular mechanisms of eugenol for cancer prevention and therapy.

METHODS

Based on predetermined criteria, various scholarly repositories, including PubMed, Scopus, and Science Direct were analyzed for anticancer activities of eugenol.

RESULTS

Different biochemical investigations reveal eugenol inducing cytotoxicity, inhibiting phases of the cell cycles, programmed cell death, and auto-phagocytosis in studied cancer lines; thus, portraying eugenol as a promising anticancer molecule. A survey of current literature has unveiled the molecular mechanisms intervened by eugenol in exercising its anticancer role.

CONCLUSION

Based on the critical analysis of the literature, eugenol exhibits vivid signaling pathways to combat cancers of different origins. The reports also depict the advancement of novel nano-drug delivery approaches upgrading the therapeutic profile of eugenol. Therefore, eugenol nanoformulations may have enormous potential for both the treatment and prevention of cancer.

Piperlongumine increases the sensitivity of bladder cancer to cisplatin by mitochondrial ROS

BACKGROUND

The development of cisplatin resistance often results in cisplatin inefficacy in advanced or recurrent bladder cancer. However, effective treatment strategies for cisplatin resistance have not been well established.

METHODS

Gene expression was measured by qRT-PCR and Western blotting. CCK-8 assay was performed to detect cell survival. The number of apoptotic cells was determined using the Annexin V-PI double-staining assay. The level of reactive oxygen species (ROS) was measured using 2',7'-dichlorodihydrofluorescein diacetate fluorescent dye, and the ATP level was detected using an ATP measurement kit.

RESULTS

The expression of receptor-interacting protein kinase 1 (RIPK1), a key regulator of necroptosis, gradually decreased during cisplatin resistance. We first used piperlongumine (PL) in combination with cisplatin to act on cisplatin-resistant BC cells and found that PL-induced activation of RIPK1 increased the sensitivity of T24 resistant cells to cisplatin treatment. Furthermore, we revealed that PL killed T24 cisplatin-resistant cells by triggering necroptosis, because cell death could be rescued by the mixed lineage kinase domain-like (MLKL) protein inhibitor necrotic sulfonamide or MLKL siRNA, but could not be suppressed by the apoptosis inhibitor z-VAD. We further explored the specific mechanism and found that PL activated RIPK1 to induce necroptosis in cisplatin-resistant cells by stimulating mitochondrial fission to produce excessive ROS.

CONCLUSIONS

Our results demonstrated the role of RIPK1 in cisplatin-resistant cells and the sensitization effect of the natural drug PL on bladder cancer. These may provide a new treatment strategy for overcoming cisplatin resistance in bladder cancer.

The Healing Capability of Clove Flower Extract (CFE) in Streptozotocin-Induced (STZ-Induced) Diabetic Rat Wounds Infected with Multidrug Resistant Bacteria

Treatment of diabetic foot ulcer (DFU) is of great challenge as it is shown to be infected by multidrug resistant bacteria (MDR bacteria). Sixty four bacterial isolates were isolated from DFU cases; antibiotic susceptibility tests were carried out for all of them. One bacterial isolate (number 11) was shown to resist the action of 8 out of 12 antibiotics used and was identified by both a Vitek-2 system and 16S rRNA fingerprints as belonging to Proteus mirabilis, and was designated Proteus mirabilis LC587231 (P. mirabilis). Clove flower extract (CFE) inhibited distinctively the P. mirabilis bacterium obtained. GC-MS spectroscopy showed that this CFE contained nine bioactive compounds. The effect of CFE on wound healing of Type 1 diabetic albino rats (Rattus norvegicus) was studied. The results indicated that topical application of CFE hydrogel improved wound size, wound index, mRNA expression of the wound healing markers (Coli1, MMP9, Fibronectin, PCNA, and TGFβ), growth factor signaling pathways (PPAR-α, PGC1-α, GLP-1, GLPr-1, EGF-β, EGF-βr, VEGF-β, and FGF-β), inflammatory cytokine expression (IL8, TNFα, NFKβ, IL1β, and MCP1), as well as anti-inflammatory cytokines (IL4 & IL10), pro-apoptotic markers (FAS, FAS-L, BAX, BAX/BCL-2, Caspase-3, P53, P38), as well as an antiapoptotic one (BCL2). Furthermore, it improved the wound oxidative state and reduced the wound microbial load, as the cefepime therapy improved the wound healing parameters. Based on the previous notions, it could be concluded that CFE represents a valid antibiotics alternative for DFU therapy since it improves diabetic wound healing and exerts antibacterial activity either in vitro or in vivo.

In silico molecular docking and dynamic simulation of eugenol compounds against breast cancer

Breast cancer is one of the most severe problems, and it is the primary cause of cancer-related death in females worldwide. The adverse effects and therapeutic resistance development are among the most potent clinical issues for potent medications for breast cancer treatment. The eugenol molecules have a significant affinity for breast cancer receptors. The aim of the study has been on the eugenol compounds, which has potent actions on Erα, PR, EGFR, CDK2, mTOR, ERBB2, c-Src, HSP90, and chemokines receptors inhibition. Initially, the drug-likeness property was examined to evaluate the anti-breast cancer activity by applying Lipinski's rule of five on 120 eugenol molecules. Further, structure-based virtual screening was performed via molecular docking, as protein-like interactions play a vital role in drug development. The 3D structure of the receptors has been acquired from the protein data bank and is docked with 87 3D PubChem and ZINC structures of eugenol compounds, and five FDA-approved anti-cancer drugs using AutoDock Vina. Then, the compounds were subjected to three replica molecular dynamic simulations run of 100 ns per system. The results were evaluated using root mean square deviation (RMSD), root mean square fluctuation (RMSF), and protein-ligand interactions to indicate protein-ligand complex stability. The results confirm that Eugenol cinnamaldehyde has the best docking score for breast cancer, followed by Aspirin eugenol ester and 4-Allyl-2-methoxyphenyl cinnamate. From the results obtained from in silico studies, we propose that the selected eugenols can be further investigated and evaluated for further lead optimization and drug development.

Anticancer Properties of Eugenol: A Review

Conventional cancer treatments have shown several unfavourable adverse effects, as well as an increase in anticancer drug resistance, which worsens the impending cancer therapy. Thus, the emphasis is currently en route for natural products. There is currently great interest in the natural bioactive components from medicinal plants possessing anticancer characteristics. For example, clove (Syzygium aromaticum L.) (Family Myrtaceae) is a highly prized spice that has been historically utilized as a food preservative and for diverse medical uses. It is reckoned amongst the valued sources of phenolics. It is indigenous to Indonesia but currently is cultivated in various places of the world. Among diverse active components, eugenol, the principal active component of S. aromaticum, has optimistic properties comprising antioxidant, anti-inflammatory, and anticancer actions. Eugenol (4-allyl-2-methoxyphenol) is a musky oil that is mainly obtained from clove. It has long been utilized all over the world as a result of its broad properties like antioxidant, anticancer, anti-inflammatory, and antimicrobial activities. Eugenol continues to pique investigators’ interest because of its multidirectional activities, which suggests it could be used in medications to treat different ailments. Anticancer effects of eugenol are accomplished by various mechanisms like inducing cell death, cell cycle arrest, inhibition of migration, metastasis, and angiogenesis on several cancer cell lines. Besides, eugenol might be utilized as an adjunct remedy for patients who are treated with conventional chemotherapy. This combination leads to a boosted effectiveness with decreased toxicity. The present review focuses on the anticancer properties of eugenol to treat several cancer types and their possible mechanisms.

Eugenol modulates genomic methylation and inactivates breast cancer-associated fibroblasts through E2F1-dependent downregulation of DNMT1/DNMT3A

Active cancer-associated fibroblasts (CAFs) are major components of the tumor microenvironment, which promote carcinogenesis and modulate response to therapy. Therefore, targeting these cells or reducing their paracrine pro-carcinogenic effects could be of great therapeutic value. To this end, we sought to investigate the effect of eugenol, a natural phenolic molecule, on active breast CAFs. We have shown that decitabine (5-Aza-2'-deoxycytidine, DAC) and eugenol inhibit the expression of the DNA methyltransferase genes DNMT1 and DNMT3A at both the protein and mRNA levels in breast CAF cells. While the effect of eugenol was persistent, DAC had only a transient inhibitory effect on the mRNA level of both DNMT genes. Furthermore, eugenol and DAC suppressed the invasive/migratory and proliferative potential of CAF cells as well as their paracrine pro-carcinogenic effects both in vitro and in humanized orthotopic tumor xenografts. Interestingly, these inhibitory effects of decitabine and eugenol were mediated through E2F1 downregulation. Indeed, ectopic expression of E2F1 upregulated both genes and attenuated the effects of eugenol. Additionally, we provide clear evidence that eugenol, like DAC, strongly modulates the methylation pattern in active CAF cells, through methylating several oncogenes and demethylating various important tumor suppressor genes, which affected their mRNA expression levels. Importantly, the E2F1 promoter was also hypermethylated and the gene downregulated in response to eugenol. Together, these findings show that the active features of breast CAF cells can be normalized through eugenol-dependent targeting of DNMT1/DNMT3A and the consequent modulation in gene methylation.

The Short-Term Effect of Eugenol on the Prevention of Experimentally Induced Myringosclerosis in a Rat Model

Objective:

The aim of our study was to assess the possible short-term effects of topical and oral eugenol on the suppression of experimentally developed myringosclerosis (MS).

Methods:

Four groups of seven male Wistar albino rats were used in the study. The tympanic membranes (TMs) of all subjects were myringotomized, and group 1 was given no treatment (as control group), group 2 received saline, group 3 had received topical eugenol and group 4 received oral eugenol.

Results:

In macroscopic evaluation the control and saline groups showed much more MS compared to the topical and oral eugenol groups which had statistically significantly less changes (p<0.05). Fibrosis and inflammation regarding the lamina propria (LP) of the eardrums of the topical and oral eugenol groups were significantly less than those of the control and saline groups (p<0.001). In microscopic evaluation, TMs were found to be thicker in the control and saline groups (p<0.001).

Conclusion:

Our study showed that the application of topical and oral forms of eugenol reduced fibrosis and prevented the advancement of MS in the LP of the TMs in the short-term. More studies with different extracts are needed to investigate the efficacy of phytotherapeutic agents for preventing MS development following myringotomy.

miRNAs Modulate the Dichotomy of Cisplatin Resistance or Sensitivity in Breast Cancer: An Update of Therapeutic Implications

Cisplatin has a broad-spectrum antitumor activity and is widely used for the treatment of various malignant tumors. However, acquired or intrinsic resistance of cisplatin is a major problem for patients during the therapy. Recently, it has been reported Cancer Stem Cell (CSC)-derived drug resistance is a great challenge of tumor development and recurrence; therefore, the sensitivity of Breast Cancer Stem Cells (BCSCs) to cisplatin is of particular importance. Increasing evidence has shown that there is a relationship between cisplatin resistance/sensitivity genes and related miRNAs. It is known that dysregulation of relevant miRNAs plays a critical role in regulating target genes of cisplatin resistance/sensitivity in various pathways such as cellular uptake/efflux, Epithelial-Mesenchymal Transition (EMT), hypoxia, and apoptosis. Furthermore, the efficacy of the current chemotherapeutic drugs, including cisplatin, for providing personalized medicine, can be improved by controlling the expression of miRNAs. Thus, potential targeting of miRNAs can lead to miRNA-based therapies, which will help overcome drug resistance and develop more effective personalized anti-cancer and cotreatment strategies in breast cancer. In this review, we summarized the general understandings of miRNAregulated biological processes in breast cancer, particularly focused on the role of miRNA in cisplatin resistance/ sensitivity.

Biological Properties and Prospects for the Application of Eugenol-A Review

Eugenol is a phenolic aromatic compound obtained mainly from clove oil. Due to its known antibacterial, antiviral, antifungal, anticancer, anti-inflammatory and antioxidant properties, it has long been used in various areas, such as cosmetology, medicine, and pharmacology. However, high concentrations can be toxic. A dose of 2.5 mg/kg body weight is regarded as safe. This paper reviews the current state of knowledge regarding the activities and application of eugenol and its derivatives and recent research of these compounds. This review is based on information concerning eugenol characteristics and recent research from articles in PubMed. Eugenol remains of great interest to researchers, since its multidirectional action allows it to be a potential component of drugs and other products with therapeutic potential against a range of diseases.

Pleiotropic Effects of Eugenol: The Good, the Bad, and the Unknown

Phytocompounds and medicinal herbs were used in traditional ancient medicine and are nowadays increasingly screened in both experimental and clinical settings due to their beneficial effects in several major pathologies. Similar to the drug industry, phytotherapy is interested in using nanobased delivery systems to view the identification and characterization of the cellular and molecular therapeutic targets of plant components. Eugenol, the major phenolic constituent of clove essential oil, is a particularly versatile phytochemical with a vast range of therapeutic properties, among which the anti-inflammatory, antioxidant, and anticarcinogenic effects have been systematically addressed. In the past decade, with the emerging understanding of the role of mitochondria as critical organelles in the pathophysiology of noncommunicable diseases, research regarding the role of phytochemicals as modulators of bioenergetics and metabolism is on a rise. Here, we present a brief overview of the major pharmacological properties of eugenol, with special emphasis on its applications in dental medicine, and provide preliminary data regarding its effects, alone, and included in polyurethane nanostructures, on mitochondrial bioenergetics, and glycolysis in human HaCaT keratinocytes.

Epigenetic immunomodulatory effect of eugenol and astaxanthin on doxorubicin cytotoxicity in hormonal positive breast Cancer cells

BACKGROUND

Hormonal receptor positive (HR+) breast cancer is the most commonly diagnosed molecular subtype of breast cancer; which showed good response to doxorubicin (DOX)-based chemotherapy. Eugenol (EUG) and astaxanthin (AST) are natural compounds with proved epigenetic and immunomodulatory effects in several cancer cell lines. This study has been initiated to investigate the molecular mechanism (s) whereby EUG and AST could enhance DOX cytotoxicity in MCF7 cells.

METHODS

Cytotoxic activity of DOX alone and combined with either 1 mM EUG or 40 μM AST was performed using sulphorhodamine-B assay in MCF7 cells. Global histones acetylation and some immunological markers were investigated using ELISA, western blotting and quantitative RT-PCR techniques. Functional assay of multidrug resistance was performed using rhodamine 123 and Hoechst 3342 dyes. Flow cytometry with annexin V and propidium iodide were used to assess the change in cell cycle and apoptosis along with the expression of some differentiation, apoptosis and autophagy proteins.

RESULTS

DOX alone resulted in concentration-dependent cytotoxicity with IC50 of 0.5 μM. Both EUG and AST significantly increased DOX cytotoxicity which is manifested as a significant decrease in DOX IC50 from 0.5 μM to 0.088 μM with EUG and to 0.06 μM with AST. Combinations of DOX with 1 mM EUG or 40 μM AST significantly increased the level of histones acetylation and histone acetyl transferase expression, while reduced the expression of aromatase and epidermal growth factor receptor (EGFR) when compared with 0.25 μM DOX alone. Also both combinations showed higher uptake of rhodamine but lower of Hoechst stains, along with increased the percentage of caspase 3, and decreased the expression of CK7 and LC3BI/II ratio. EUG combination induced IFγ but reduced TNFα causing shifting of cells from G2/M to S and G0/ G1 phases. Combination of DOX with EUG induced apoptosis through the higher BAX/ BCl2 ratio, while with AST was through the increase in caspase 8 expressions.

CONCLUSION

EUG and AST potentiated the anticancer activity of DOX through epigenetic histones acetylation along with the immunonomodulation of different apoptotic approaches in MCF7 cells.

The signaling pathways and targets of traditional Chinese medicine and natural medicine in triple-negative breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Triple-negative breast cancer (TNBC) has a poorer prognosis than other subtypes due to its strong invasion and higher risk of distant metastasis. Traditional Chinese medicine (TCM) and natural medicine have the unique advantages of multitargets and small side-effects and may be used as long-term complementary and alternative therapies.

AIM OF THE REVIEW

The present article summarizes the classical signaling pathways and potential targets by the action of TCM and natural medicine (including extracts, active constituents and formulas) on TNBC and provides evidence for its clinical efficacy.

METHODS

The literature information was acquired from the scientific databases PubMed, Web of Science and CNKI from January 2010 to June 2020, and it was designed to elucidate the internal mechanism and role of TCM and natural medicine in the treatment of TNBC. The search key words included "Triple negative breast cancer" or "triple negative breast carcinoma", "TNBC" and "traditional Chinese medicine" or "Chinese herbal medicine", "medicinal plant", "natural plant", and "herb".

RESULTS

We described the antitumor activity of TCM and natural medicine in TNBC based on different signaling pathways. Plant medicine and herbal formulas regulated the related gene and protein expression via pathways such as PI3K/AKT/mTOR, MAPK and Wnt/β-catenin, which inhibit the growth, proliferation, migration, invasion and metastasis of TNBC cells.

CONCLUSION

The inhibitory effect of TCM and natural medicine on tumors was reflected in multiple levels and multiple pathways, providing reasonable evidence for new drug development. To make TCM and natural medicine widely and flexibly used in clinical practice, the efficacy, safety and mechanism of action need more in-depth experimental research.

Optimized preparation of eugenol microcapsules and its effect on hepatic steatosis in HepG2 cells

This study was aimed at evaluating the potential of peach gum (PG) and gelatin in the microencapsulation of eugenol and the intervention of eugenol microcapsules on hepatic steatosis in vitro. Response surface method (RSM) was used to optimize the encapsulation conditions of eugenol microcapsules. The microcapsules were characterized by scanning electron microscopy (SEM), dynamic Light Scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and release behavior in vitro was determined. The effect of eugenol microcapsules on free fatty acids (FFA) treated hepatocellular cells (HepG₂) cells was evaluated by oil red O staining and intracellular total cholesterol (TC) and triglyceride (TG) determination. The results showed that the optimal encapsulation conditions were as follows: the PG-gelatin ratio was 1.6:1.4, the core-wall ratio was 1.6:1.4, the pH was 4 and the emulsification speed was 9000 r/min. The optimized microcapsules were smooth spherical with a size of about 3.09 ± 0.58 μm and the encapsulation was confirmed by FT-IR. In vitro release behavior showed that eugenol microcapsules could be released stably in a neutral environment for 72 h. Oil red O staining showed that 50 and 100 μM eugenol microcapsules could significantly inhibit the lipid accumulation and reduce the TC and TG in steatotic HepG₂ cells induced by FFA. Therefore, PG and gelatin can be used as excellent carriers for the microencapsulation of volatile compounds in the field of biomedical industry, and eugenol microcapsules is a promising preparation for the treatment of nonalcoholic fatty liver disease (NAFLD).

Adipose Mesenchymal Stem Cell-Derived Exosomal microRNA-1236 Reduces Resistance of Breast Cancer Cells to Cisplatin by Suppressing SLC9A1 and the Wnt/β-Catenin Signaling

BACKGROUND

Emerging evidence has noted the versatile functions of mesenchymal stem cell-derived exosomes (MSC-Exos) in cancer control. This work aims to probe to function of adipose MSC-Exos (adMSC-Exos) in drug-resistance of breast cancer (BC) cells to cisplatin (DDP) and the molecules involved.

METHODS

Parental and DDP-resistant BC cell lines MCF-7 and MDA-MB-231 were used. All cells were pre-treated with adMSC-Exos. Then, the viability and apoptosis of cells after DDP treatment were determined. Differentially expressed miRNAs after adMSC-exo treatment were screened out. Rescue experiments were conducted by pre-transfecting miR-1236 inhibitor into adMSCs, and the role of miR-1236 in DDP sensitivity was determined. Targeting mRNAs of miR-1236 were predicted by bioinformatics analysis. Altered SLC9A1 expression was administrated to evaluate its function in DDP resistance.

RESULTS

The adMSC-Exos notably increased the sensitivity of either parental or DDP-resistant BC cells to DDP. SLC9A1 was notably highly expressed in DDP-resistant cells but inhibited following adMSC-exo administration. Importantly, miR-1236, which could directly bind to SLC9A1 and suppress its expression, was confirmed as an enriched miRNA in adMSC-Exos. Either inhibition of miR-1236 or upregulation of SLC9A1 blocked the pro-sensitize roles of adMSC-Exos. In addition, the Wnt/β-catenin pathway activity was suppressed by adMSC-Exos but recovered by SLC9A1.

CONCLUSION

This study evidenced that adMSC-Exos carry miR-1236 to increase sensitivity of BC cells to DDP with the involvement of SLC9A1 downregulation and Wnt/β-catenin inactivation. This finding may offer novel insights into treatment for drug-resistant BC.

A novel series of substituted 1,2,3-triazoles as cancer stem cell inhibitors: Synthesis and biological evaluation

An alarming increase in global death toll resulting from cancer incidents, particularly due to multidrug resistance and reduced efficacy as a consequence of target mutations, has compelled us to look for novel anticancer agents. Cancer stem cells (CSCs), contributing majorly to the chemoresistance and tumor relapse, seem to the main culprits. In the present investigation, new chemical entities (NCEs) belonging to four novel chemical series (A: 4'-allyl-2'-methoxyphenoxymethyl-1,2,3-triazoles; B: 4'-acetamidophenoxymethyl-1,2,3-triazoles; C: naphthalene-1'-yloxymethyl-1,2,3-triazoles, and D: naphthalene-2'-yloxymethyl-1,2,3-triazoles) were synthesized via Copper (I)-catalyzed alkyne-azide cycloaddition reaction and evaluated for in vitro anticancer activity. A total of 30 NCEs (39-68) were screened at 10 μM concentration in cell viability assay against cancer cell lines such as breast (MDA-MB-231), prostate (PC-3), glioma (U87 MG), along with cervical (SiHa) and lung (A549). The NCEs from Series C (56-60) and D (61-68) were more potent than those in Series A (39-45) and Series B (46-55) at the tested concentration. Furthermore, NCEs with >80% inhibition at 10 μM were evaluated for dose response. A total of five NCEs, 48, 56, 61, 65 and 66, were further assessed in soft-agar assay and found to be relatively potent (IC₅₀  < 10 μM). Finally, the hits were screened in sphere assay to identify potential CSC inhibitors against mammospheres (MDA-MB-231) and prostatospheres (PC-3). More so, the hits were also evaluated to understand in vitro cytotoxicity against normal cells using mouse embryonic fibroblast cell line (NIH/3T3) and human peripheral blood mononuclear cells (hPBMCs). Overall, hits 56 and 61 exhibited potent anticancer as well as CSC inhibitory activities with notably less toxicity toward NIH/3T3 and hPBMCs. On the whole, our arduous study led to the identification of potential hits with anticancer and CSC inhibitory activities, with minimal or no toxicity to normal cells.

Association of the Epithelial-Mesenchymal Transition (EMT) with Cisplatin Resistance

Therapy resistance is a characteristic of cancer cells that significantly reduces the effectiveness of drugs. Despite the popularity of cisplatin (CP) as a chemotherapeutic agent, which is widely used in the treatment of various types of cancer, resistance of cancer cells to CP chemotherapy has been extensively observed. Among various reported mechanism(s), the epithelial-mesenchymal transition (EMT) process can significantly contribute to chemoresistance by converting the motionless epithelial cells into mobile mesenchymal cells and altering cell-cell adhesion as well as the cellular extracellular matrix, leading to invasion of tumor cells. By analyzing the impact of the different molecular pathways such as microRNAs, long non-coding RNAs, nuclear factor-κB (NF-ĸB), phosphoinositide 3-kinase-related protein kinase (PI3K)/Akt, mammalian target rapamycin (mTOR), and Wnt, which play an important role in resistance exhibited to CP therapy, we first give an introduction about the EMT mechanism and its role in drug resistance. We then focus specifically on the molecular pathways involved in drug resistance and the pharmacological strategies that can be used to mitigate this resistance. Overall, we highlight the various targeted signaling pathways that could be considered in future studies to pave the way for the inhibition of EMT-mediated resistance displayed by tumor cells in response to CP exposure.

Othman E, Saad Eldien HM, Yoshida T. Preconditioning of Adipose-Derived Mesenchymal Stem-Like Cells with Eugenol Potentiates Their Migration and Proliferation In Vitro and Therapeutic Abilities in Rat Hepatic Fibrosis

Mesenchymal stem cells (MSCs) have considerable therapeutic abilities in various disorders, including hepatic fibrosis. They may be affected with different culture conditions. This study investigated, on molecular basics, the effect of pretreatment with eugenol on the characteristics of adipose tissue-derived MSCs (ASCs) in vitro and the implication of eugenol preconditioning on the in vivo therapeutic abilities of ASCs against CCl₄-induced hepatic fibrosis in rats. The effect of eugenol on ASCs was assessed using viability, scratch migration and sphere formation assays. Expressions of genes and proteins were estimated by immunofluorescence or qRT-PCR. For the in vivo investigations, rats were divided into four groups: the normal control group, fibrotic (CCl₄) group, CCl₄+ASCs group and CCl₄ + eugenol-preconditioned ASCs (CCl₄+E-ASCs) group. Eugenol affected the viability of ASCs in a concentration- and time-dependent manner. Eugenol improved their self-renewal, proliferation and migration abilities and significantly increased their expression of c-Met, reduced expression 1 (Rex1), octamer-binding transcription factor 4 (Oct4) and nanog genes. Furthermore, E-ASCs showed more of a homing ability than ASCs and improved the serum levels of ALT, AST, albumin, total bilirubin and hyaluronic acid more efficient than ASCs in treating CCl₄-induced hepatic fibrosis, which was confirmed with histopathology. More interestingly, compared to the CCl₄+ASCs group, CCl₄+E-ASCs group showed a lower expression of inducible nitric oxide synthase (iNOS), monocyte chemoattractant protein-1 (MCP-1), cluster of differentiation 163 (CD163) and tumor necrosis factor-α (TNF-α) genes and higher expression of matrix metalloproteinase (MMP)-9 and MMP-13 genes. This study, for the first time, revealed that eugenol significantly improved the self-renewal, migration and proliferation characteristics of ASCs, in vitro. In addition, we demonstrated that eugenol-preconditioning significantly enhanced the therapeutic abilities of the injected ASCs against CCl₄-induced hepatic fibrosis.

Nutraceutical Boom in Cancer: Inside the Labyrinth of Reactive Oxygen Species

In recent years, epidemiological studies have shown that food is a very powerful means for maintaining a state of well-being and for health prevention. Many degenerative, autoimmune and neoplastic diseases are related to nutrition and the nutrient-organism interaction could define the balance between health and disease. Nutrients and dietary components influence epigenetic phenomena and modify drugs response; therefore, these food-host interactions can influence the individual predisposition to disease and its potential therapeutic response. Do nutraceuticals have positive or negative effects during chemotherapy? The use of nutraceutical supplements in cancer patients is a controversial debate without a definitive conclusion to date. During cancer treatment, patients take nutraceuticals to alleviate drug toxicity and improve long-term results. Some nutraceuticals may potentiate the effect of cytotoxic chemotherapy by inducing cell growth arrest, cell differentiation, and alteration of the redox state of cells, but in some cases, high levels of them may interfere with the effectiveness of chemotherapy, making cancer cells less reactive to chemotherapy. In this review, we highlighted the emerging opinions and data on the pros and cons on the use of nutraceutical supplements during chemotherapy.

Eugenol Exerts Apoptotic Effect and Modulates the Sensitivity of HeLa Cells to Cisplatin and Radiation

Eugenol is a phytochemical present in different plant products, e.g., clove oil. Traditionally, it is used against a number of different disorders and it was suggested to have anticancer activity. In this study, the activity of eugenol was evaluated in a human cervical cancer (HeLa) cell line and cell proliferation was examined after treatment with various concentrations of eugenol and different treatment durations. Cytotoxicity was tested using lactate dehydrogenase (LDH) enzyme leakage. In order to assess eugenol’s potential to act synergistically with chemotherapy and radiotherapy, cell survival was calculated after eugenol treatment in combination with cisplatin and X-rays. To elucidate its mechanism of action, caspase-3 activity was analyzed and the expression of various genes and proteins was checked by RT-PCR and western blot analyses. Eugenol clearly decreased the proliferation rate and increased LDH release in a concentration- and time-dependent manner. It showed synergistic effects with cisplatin and X-rays. Eugenol increased caspase-3 activity and the expression of Bax, cytochrome c (Cyt-c), caspase-3, and caspase-9 and decreased the expression of B-cell lymphoma (Bcl)-2, cyclooxygenase-2 (Cox-2), and interleukin-1 beta (IL-1β) indicating that eugenol mainly induced cell death by apoptosis. In conclusion, eugenol showed antiproliferative and cytotoxic effects via apoptosis and also synergism with cisplatin and ionizing radiation in the human cervical cancer cell line.

New Insights in the Pathogenesis of Cisplatin-Induced Nephrotoxicity

Cisplatin (cis-diamminedichloroplatinum II) is a widely used chemotherapeutic agent. However, efficacy and clinical utility of this drug is significantly limited by severe side effects such as nephrotoxicity which develops due to renal accumulation and bio-transformation in proximal tubular epithelial cells. Cisplatin-induced nephrotoxicity can be manifested as acute kidney injury (AKI), or as different types of tubulopathies, salt wasting, loss of urinary concentrating ability, and magnesium wasting. The attenuation of cisplatin-caused AKI is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis. However, mannitol treatment causes over-diuresis and consequent dehydration, indicating an urgent need for the clinical use of newly designed, safe and efficacious renoprotective drug, as an additive therapy for high dose cisplatin-treated patients. Accordingly, we emphasized current knowledge regarding molecular mechanisms responsible for cisplatin-caused nephrotoxicity and we described in detail the main clinical manifestations of cisplatin-induced renal dysfunction in order to pave the way for the design of new therapeutic approaches that can minimize detrimental effects of cisplatin in the kidneys. Having in mind that most of cisplatin-induced cytotoxic effects against renal cells are, at the same time, involved in anti-tumor activity of cisplatin, new nephroprotective therapeutic strategies have to prevent renal injury and inflammation without affecting cisplatin-induced toxicity against malignant cells.

Sequential combination of cisplatin with eugenol targets ovarian cancer stem cells through the Notch-Hes1 signalling pathway

Background

Ovarian carcinomas are the deadliest gynecological malignancies owing to their high rate of recurrence and high resistance to platinum-based chemotherapy. Recent studies have shown platinum-dependent enrichment of ovarian tumors with side population as well as cancer stem cells, which are highly resistant to the treatment. To overcome this treatment-limiting factor, we sought to combine cisplatin with eugenol, a natural substance known to have anti-cancer effects.

Methods

The efficiency of combining cisplatin with eugenol was first tested in vitro on two ovarian cancer cell lines SKOV3 and OV2774 using the WST1 and the flow cytometry techniques. The effect of this combination on ovarian cancer stem cells was determined by the tumorsphere formation assay, while the implication of the Notch pathway was evaluated post-ectopic expression of the Hes1 gene. The resulting changes in the expression of several markers was assessed by immunoblotting, immunofluorescence as well as quantitative RT-PCR. Cell sorting was also used to isolate specific ovarian cancer sub-population of cells. Furthermore, tumor-bearing mouse models were utilized to prove the potential therapeutic value of the cisplatin/eugenol combination treatment in vivo.

Results

We have shown that adding eugenol to cisplatin-treated ovarian cancer cells synergistically inhibited their growth and survival through induction of apoptosis. Importantly, this sequential inhibition strongly reduced the proportion of side population cells and suppressed cisplatin-dependent enrichment in ovarian cancer stem cells. Additionally, while increase in the level of Hes1 promoted stemness and enhanced resistance to cisplatin, cisplatin/eugenol cotreatment inhibited the Notch-Hes1 pathway and strongly downregulated the drug resistance ABC transporter genes. These findings were confirmed in vivo by showing that cisplatin/eugenol cotherapy inhibited tumor growth in animals, reduced the proportion and self-renewal capacities of cancer stem cells and significantly improved disease-free survival of tumor-bearing animals compared with either therapy alone.

Conclusions

These results indicate that cisplatin/eugenol sequential combination could be of great therapeutic value for ovarian cancer patients through targeting the Notch-Hes1 pathway and the consequent elimination of the resistant cancer stem cells.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1360-3) contains supplementary material, which is available to authorized users.

Phytochemicals: Current strategy to sensitize cancer cells to cisplatin

Cisplatin-based chemotherapeutic regimens are the most frequently used adjuvant treatments for many types of cancer. However, the development of chemoresistance to cisplatin results in treatment failure. Despite the significant developments in understanding the mechanisms of cisplatin resistance, effective strategies to enhance the chemosensitivity of cisplatin are lacking. Phytochemicals are naturally occurring plant-based compounds that can augment the anti-cancer activity of cisplatin, with minimal side effects. Notably, some novel phytochemicals, such as curcumin, not only increase the efficacy of cisplatin but also decrease toxicity induced by cisplatin. However, the exact mechanisms underlying this process remain unclear. In this review, we discussed the progress made in utilizing phytochemicals to enhance the anti-cancer efficacy of cisplatin. We also presented some ideal phytochemicals as novel agents for counteracting cisplatin-induced organ damage.

An Overview on the Anti-inflammatory Potential and Antioxidant Profile of Eugenol

The bioactive compounds found in foods and medicinal plants are attractive molecules for the development of new drugs with action against several diseases, such as those associated with inflammatory processes, which are commonly related to oxidative stress. Many of these compounds have an appreciable inhibitory effect on oxidative stress and inflammatory response, and may contribute in a preventive way to improve the quality of life through the use of a diet rich in these compounds. Eugenol is a natural compound that has several pharmacological activities, action on the redox status, and applications in the food and pharmaceutical industry. Considering the importance of this compound, the present review discusses its anti-inflammatory and antioxidant properties, demonstrating its mechanisms of action and therapeutic potential for the treatment of inflammatory diseases.

Breast cancer stem cells: Features, key drivers and treatment options

The current view is that breast cancer is a stem cell disease characterized by the existence of cancer cells with stem-like features and tumor-initiating potential. These cells are made responsible for tumor dissemination and metastasis. Common therapies by chemotherapeutic drugs fail to eradicate these cells and rather increase the pool of cancer stem cells in tumors, an effect that may increase the likelyhood of recurrence. Fifteen years after the first evidence for a small stem-like subpopulation playing a major role in breast cancer initiation has been published a large body of knowledge has been accumulated regarding the signaling cascades and proteins involved in maintaining stemness in breast cancer. Differences in the stem cell pool size and in mechanisms regulating stemness in the different breast cancer subtypes have emerged. Overall, this knowledge offers new approaches to intervene with breast cancer stem cell activity. New options are particularly needed for the treatment of triple-negative breast cancer subtype, which is particularly rich in cancer stem cells and is also the subtype for which specific therapies are still not available.