7,8-Dihydroxycoumarin exerts antitumor potential on DMBA-induced mammary carcinogenesis by inhibiting ERα, PR, EGFR, and IGF1R: involvement of MAPK1/2-JNK1/2-Akt pathway

The molecular effects underlying the pharmacological activities of daphnetin

As an increasingly well-known derivative of coumarin, daphnetin (7,8-dithydroxycoumarin) has demonstrated various pharmacological activities, including anti-inflammation, anti-cancer, anti-autoimmune diseases, antibacterial, organ protection, and neuroprotection properties. Various studies have been conducted to explore the action mechanisms and synthetic methods of daphnetin, given its therapeutic potential in clinical. Despite these initial insights, the precise mechanisms underlying the pharmacological activities of daphnetin remain largely unknown. In order to address this knowledge gap, we explore the molecular effects from the perspectives of signaling pathways, NOD-like receptor protein 3 (NLRP3) inflammasome and inflammatory factors; and try to find out how these mechanisms can be utilized to inform new combined therapeutic strategies.

3,3'-((3,4,5-trifluoropHenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) inhibit lung cancer cell proliferation and migration

Lung cancer is a major public health challenge and, despite therapeutic improvements, is the first leading cause of cancer worldwide. The current cure rate from advanced cancer treatment is excessively low. Therefore, it is of great importance to identify novel, potent and less toxic anticancer agents for the treatment of lung cancer. The aim of our research is to synthesize a new biscoumarin 3,3'-((3,4,5-trifluorop -phenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) (C35) as an anticancer agent. C35 was simply prepared by 4-hydroxycoumarin and 3,4,5-trifluorobenzaldehyde under ethanol and its structure was analyzed by spectroscopic analyses. The anti-proliferation effect of C35 was detected using CCK-8 assay. Migration abilities were measured by Transwell assay. The expression of correlated proteins was determined by Western blot. The results showed that C35 displayed strong cytostatic effects on lung cancer cell proliferation. In addition, C35 possessed a significant inhibition of migration by reducing the expression of matrix metalloproteinases-2 (MMP-2) and MMP-9 in lung cancer cells. Furthermore, C35 treatment suppressed the phosphorylation of p38 in lung cancer cells. Moreover, in vivo experiments were carried out, in which we treated Lewis tumor-bearing C57 mice via intraperitoneal injection of C35. Results showed that C35 inhibited tumor growth in vivo. In conclusion, our study demonstrated the anticancer activity of C35 via suppression of lung cancer cell proliferation and migration, which is possibly involved with the inhibition of the p38 pathway.

Daphnetin, a Coumarin with Anticancer Potential against Human Melanoma: In Vitro Study of Its Effective Combination with Selected Cytostatic Drugs

(1) The treatment of metastatic or drug-resistant melanoma is still a significant therapeutic problem. The aim of this study was to evaluate the anticancer potential of daphnetin (7,8-dihydroxycoumarin) and its combinations with five different cytostatic drugs (mitoxantrone, docetaxel, vemurafenib, epirubicin and cisplatin). (2) The viability, proliferation and cytotoxicity of daphnetin against four human malignant melanoma cell lines were evaluated. The interactions were assessed using isobolographic analysis for the combinations of daphnetin with each of the five cytostatic drugs. (3) Daphnetin showed anticancer activity against malignant melanoma, with IC₅₀ values ranging from 40.48 ± 10.90 µM to 183.97 ± 18.82 µM, depending on the cell line. The combination of daphnetin with either vemurafenib or epirubicin showed an antagonistic interaction. Moreover, additive interactions were observed for the combinations of daphnetin with cisplatin and docetaxel. The most desirable synergistic interactions for human melanoma metastatic cell lines were observed for the combination of daphnetin with mitoxantrone. (4) The obtained results suggest that daphnetin should not be combined with vemurafenib or epirubicin in the treatment of malignant melanoma due to the abolition of their anticancer effects. The combination of daphnetin with mitoxantrone is beneficial in the treatment of metastatic melanoma due to their synergistic interaction.

Therapeutic silencing of mTOR by systemically administered siRNA-loaded neutral liposomal nanoparticles inhibits DMBA-induced mammary carcinogenesis

BACKGROUND

Mammary carcinogenesis possesses great challenges due to the lack of effectiveness of the multiple therapeutic options available. Gene therapy-based cancer treatment strategy provides more targeting accuracy, fewer side effects, and higher therapeutic efficiency. Downregulation of the oncogene mTOR by mTOR-siRNA is an encouraging approach to reduce cancer progression. However, its employment as means of therapeutic strategy has been restricted due to the unavailability of a suitable delivery system.

METHODS

A suitable nanocarrier system made up of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) has been developed to prevent degradation and for proficient delivery of siRNA. This was followed by in vitro and in vivo anti-breast cancer efficiency analysis of the mTOR siRNA-loaded neutral liposomal formulation (NL-mTOR-siRNA).

RESULTS

In our experiment, a profound reduction in MCF-7 cell growth, proliferation and invasion was ascertained following extensive downregulation of mTOR expression. NL-mTOR-siRNA suppressed tumour growth and restored morphological alterations of DMBA-induced breast cancer. In addition, neutral liposome enhanced accumulation of siRNA in mammary cancer tissues facilitating its deep cytosolic distribution within the tumour, which allows apoptosis thereby facilitating its anti-tumour potential.

CONCLUSION

Hence, the current study highlighted the augmented ground for therapies aiming toward cancerous cells to diminish mTOR expression by RNAi in managing mammary carcinoma.

Dietary phytochemicals targeting Nrf2 for chemoprevention in breast cancer

Breast cancer accounts for 11.7% of all newly diagnosed cancer cases and has become the leading cause of cancer worldwide. Currently, more effective and less toxic chemopreventive strategies for breast cancer are urgently needed. Notably, naturally occurring dietary phytochemical compounds, such as curcumin and resveratrol, are generally considered to be the most promising breast cancer preventive agents. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that plays a key regulatory role in the expression of multiple antioxidant and anti-inflammatory enzymes, which can effectively suppress the excessive accumulation of carcinogens and their metabolites. Therefore, modulation of Nrf2 by dietary phytochemicals appears to be a promising approach for breast cancer prevention, which further removes excessive carcinogenic metabolites by inducing Phase II cytoprotective enzymes such as heme oxygenase-1 (HO-1) and NAD(P)H quinine oxidoreductase 1 (NQO1). In this review, we summarize recently published findings on the prevention of breast cancer with potential natural phytochemical compounds targeting Nrf2, as well as a mechanistic discussion of Nrf2 activation and its contribution in inhibiting breast cancer carcinogenesis. The epigenetic regulation of Nrf2 by phytochemicals is also explored.

Screening for Active Compounds Targeting Human Natural Killer Cell Activation Identifying Daphnetin as an Enhancer for IFN-γ Production and Direct Cytotoxicity

Natural killer (NK) cells are a potent weapon against tumor and viral infection. Finding active compounds with the capacity of enhancing NK cell effector functions will be effective to develop new anti-cancer drugs. In this study, we initially screened 287 commercially available active compounds by co-culturing with peripheral blood mononuclear cells (PBMCs). We found that five compounds, namely, Daphnetin, MK-8617, LW6, JIB-04, and IOX1, increased the IFN-γ⁺ NK cell ratio in the presence of IL-12. Further studies using purified human primary NK cells revealed that Daphnetin directly promoted NK cell IFN-γ production in the presence of IL-12 but not IL-15, while the other four compounds acted on NK cells indirectly. Daphnetin also improved the direct cytotoxicity of NK cells against tumor cells in the presence of IL-12. Through RNA-sequencing, we found that PI3K-Akt-mTOR signaling acted as a central pathway in Daphnetin-mediated NK cell activation in the presence of IL-12. This was further confirmed by the finding that both inhibitors of PI3K-Akt and its main downstream signaling mTOR, LY294002, and rapamycin, respectively, can reverse the increase of IFN-γ production and cytotoxicity in NK cells promoted by Daphnetin. Collectively, we identify a natural product, Daphnetin, with the capacity of promoting human NK cell activation via PI3K-Akt-mTOR signaling in the presence of IL-12. Our current study opens up a new potential application for Daphnetin as a complementary immunomodulator for cancer treatments.

Kolaviron pre-treatment suppresses 7, 12 dimethylbenzanthracene-induced alterations in estrogen receptor-α, CYP 1A1, oxidative stress and inflammation in female Wistar rats

Due to the need to develop locally available, cheaper, and efficacious treatment regimens for breast cancer, the chemopreventive effect of kolaviron (KV), an extract of Garcinia kola seeds was examined. Fifty (50) female Wistar rats (120-180 g) were assigned to five groups (control group, 7, 12 dimethylbenzanthracene [DMBA] groups, tamoxifen group) of 10 rats each. They were pre-treated with KV thrice a week for four weeks except control. Estrogen receptor-α (ER-α) levels were determined in the pre-treated rats before induction of mammary carcinogenesis. After the four weeks pre-treatment period, 80 mg/kg of DMBA was used for induction. A hundred and fifty (150) days after induction, the rats were sacrificed humanely. Significantly higher levels of ER-α, formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration, increased cytokines (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]), CYP1A1 activity and malondialdehyde (MDA) with a corresponding decrease in superoxide dismutase (SOD), catalase and glutathione peroxidase were observed in DMBA-induced rats. Pre-treatment with KV at 200 mg/kg body weight significantly (p < .05) decreased ER-α levels by 19.01% and 37.52%, [IL-6] by 36.37% and 20.55%, TNF-α by 42.2% and 12.33% in serum and mammary tissue respectively. Also, a significant (p < .05) decrease in serum CYP1A1 activity, MDA with concomitant increase in SOD, catalase and glutathione peroxidase activities were observed in serum and mammary tissue respectively. Collectively, the results suggest that KV could be further explored in targeting chemoprevention of DMBA-induced mammary damage. PRACTICAL APPLICATIONS: Garcinia kola is widely cultivated in West and Central Africa with kolaviron (KV) as its major constituents. The seeds which have a bitter astringent taste are widely consumed by people in the region. Locals claim that consumption of the seeds provides relief for the management of several ailments including cancer. However, scientific investigations that provide a basis for these claims are still needed. This study provides evidence that points to the ameliorative potential of KV on breast cancer model. The results will be beneficial to local communities who hitherto had no knowledge on the potential of G. kola in chemoprevention. The results from this study will also attract further research attention from the international scientific community to examine the anti-cancer benefits of G. kola. This will also be beneficial to the global community due to the increasing number of breast cancer cases recorded annually.

Preventive Effect of Combined Zingiber officinale and Terminalia chebula against DMBA-Induced Breast Cancer Rats via mTOR Inhibition

Zingiber officinale (ZO) and Terminalia chebula (TC) are plants used for the treatment of diverse illnesses in traditional medicine. The present study investigates the preventive effect of Zingiber officinale-Terminalia chebula extract (ZOTC) against DMBA-induced breast cancer in a rat model. Bioactive compounds from ZO (6-gingerol, 6-shogaol) and TC (gallic acid, ellagic acid, corilagin, chebulinic acid, and chebulagic acid) were detected using high-performance liquid chromatography. Mammary carcinogenesis was induced in rats with a single subcutaneous injection of 7,12-Dimethylbenz[a]anthracene (DMBA). Oral administration of ZOTC ameliorated the antioxidant status in mammary tissues, serum lipid levels, and serum cytokines. Histological analysis of the mammary tissue (normal and tumor) was carried out to obtain pathological alterations due to ZOTC treatment. The effect of ZOTC on the mechanistic target of rapamycin (mTOR) gene and accumulation of corresponding gene product was also investigated. mTOR plays a central role in cell metabolism and proliferation in normal and cancer cells. Transcriptional and immunohistochemical analysis showed the downregulation of mTOR expression in the mammary tissues of ZOTC-treated rats. In conclusion, the results obtained suggest that ZOTC can suppress tumor progression in DMBA-induced breast cancer rats via inhibition of the mTOR pathway.

Daphnetin triggers ROS-induced cell death and induces cytoprotective autophagy by modulating the AMPK/Akt/mTOR pathway in ovarian cancer

BACKGROUND

Ovarian cancer is one of the most common gynecological malignancies in the world. Daphnetin (Daph) was previously reported to possess antitumor potential, but its potential and molecular mechanisms in ovarian cancer remain poorly understood.

PURPOSE

In the current study, we aimed to explore the antitumor effect and detailed mechanisms of Daph in ovarian cancer cells.

METHODS

The cytotoxic effect of Daph on ovarian cells was determined in vitro and in vivo. Cell growth, proliferation, apoptosis and ROS generation were measured by CCK8 assays, colony formation assays and flow cytometry. Western blotting was used to evaluate the related signal proteins. Immunofluorescence and transmission electron microscopy were used to evaluate markers of autophagy and autophagic flux. The antitumor effects were observed in the A2780 xenograft model. Moreover, Daph-induced autophagy was observed by enhanced LC3-II accumulation and endogenous LC3 puncta, and an autophagy inhibitor further enhanced the antitumor efficacy of Daph, which indicated that the cytoprotective role of autophagy in ovarian cancer.

RESULTS

We found that Daph exhibited antitumor effects by inducing ROS-dependent apoptosis in ovarian cancer, which could be reversed by N-acetyl cysteine (NAC). The AMPK/Akt/mTOR pathway was involved in Daph-mediated cytoprotective autophagy, and when Daph-mediated the expression level of AMPK and autophagy were blocked, there was robust inhibition of cell proliferation and induction of apoptosis. In addition, in the A2780 xenograft model, combined treatment with Daph and an autophagy inhibitor showed obvious synergetic effects on the inhibition of cell viability and promotion of apoptosis, without any side effects.

CONCLUSION

Our results suggest that Daph triggers ROS-induced cell apoptosis and induces cytoprotective autophagy by modulating the AMPK/Akt/mTOR pathway. Moreover, the combination of Daph and autophagy inhibitor may be a potential therapeutic strategy for ovarian cancer.

Daphnetin ameliorates glucocorticoid-induced osteoporosis via activation of Wnt/GSK-3β/β-catenin signaling

Glucocorticoids have been widely used in multiple inflammatory and autoimmune diseases. However, long-term glucocorticoid therapy may result in osteoporosis. The present study aimed to evaluate the potential therapeutic effects and investigate the underlying mechanisms of Daphnetin (Daph) on glucocorticoid-induced osteoporosis (GIOP). In vivo, male Sprague Dawley rats were intramuscularly injected with dexamethasone (DEX) to induce GIOP and Daph was given intraperitoneally. Bone histological changes, mineral content, microstructure parameters and bone turnover markers were detected. Gut microbiota composition and intestinal barrier function were further assessed. In vitro, MC3T3-E1 pre-osteoblasts were treated with DEX and the abilities of Daph on osteoblast proliferation, differentiation and mineralization were assessed. A Wnt signaling inhibitor, XAV939, was added additionally to evaluate the effect of Daph on Wnt signaling. The results showed that in vivo, Daph increased the DEX-induced reduction in body weight gain, bone mineral content and microstructure parameters and restored the levels of bone turnover markers in GIOP rats. In vitro, Daph promoted osteoblast proliferation, differentiation and mineralization in DEX-treated MC3T3-E1 pre-osteoblasts. Moreover, Daph activated the Wnt/GSK-3β/β-catenin signaling pathway. XAV939 successfully abolished the beneficial effects of Daph on GIOP in vitro. Besides, Daph showed improvement on gut microbiota disorder and intestinal barrier dysfunction post GIOP. Collectively, these data demonstrated that Daph effectively ameliorates GIOP and the possible mechanism may be that Daph activated Wnt/GSK-3β/β-catenin signaling.

Dimethylbenz(a)anthracene-induced mammary tumorigenesis in mice

Every year, over 2 million women are diagnosed with breast cancer. Although considerable progress was made within the last years in cancer prevention, diagnosis and treatment, breast cancer is still responsible for over 600,000 of deaths per year. Over the years, numerous mouse models have been developed to understand breast cancer etiology and progression. Among those, mammary carcinomas induced by carcinogen, such as 7,12-dimethylbenz[a]anthracene (DMBA), has been widely used. Generally, 30-70% of mice exposed to 4-6 weekly doses of 1mg of DMBA during the peripubertal period (4-10 weeks of age) will develop mammary tumors within 150-200 days after the first exposure, that sometime metastasize to the lungs. As a result, DMBA-induced tumorigenesis is thought to be an accurate and relevant model to study breast cancer as it closely mimics this multistep process. This chapter presents the typical protocol used in mice to induce mammary gland tumors using DMBA. The influence of the number of doses and the total burden of DMBA given, as well as of the age and strain of the mice on mammary gland incident and on tumor onset are discussed. The current knowledge regarding mechanisms involved in DMBA-induced tumorigenesis is also presented.

Vitex doniana Leaves Extract Ameliorates Alterations Associated with 7, 12-Dimethyl Benz[a]Anthracene-Induced Mammary Damage in Female Wistar Rats

Vitex doniana leaves are used traditionally in West Africa for the treatment of swellings and cancer. We investigated if Vitex doniana leaves extract could ameliorate 7, 12-dimethylbenz[a]anthracene (DMBA)-induced mammary damage. Female Wistar rats aged 52 ± 2 day were administered 80 mg/kg DMBA. After monitoring for 150 day, rats were administered 0, 50, 100, 200 mg/kg Vitex doniana and 20 mg/kg Tamoxifen for 14 day. Serum estrogen receptor-α, IL-1β and TNF -α levels were determined using ELISA kits. Oxidative stress markers in mammary tissue homogenates were determined using standard spectrophotometric methods. Histopathological examination was done using hematoxylin and eosin staining and cyclooxygenase-2 (COX-2) expression using immunohistochemistry. Liquid chromatography-mass spectrometry was used to determine components present in the extract. Although tumors were not observed, significantly (p < 0.05) lower estrogen receptor-α, malondialdehyde, IL-1β and TNF -α levels, significantly (p < 0.05) higher glutathione and catalase activity, attenuation of malignant epithelial hyperplasia and mild COX-2 expression were observed in rats administered Vitex doniana when compared to DMBA-induced untreated control. Liquid chromatography-mass spectrometry analysis of the V. doniana extract revealed the presence of 4,5-dihydroxy-7-methoxy-6-methylflavone and vanillylamine, which are compounds with reported antioxidant and anti-inflammatory effects. Collectively, treatment with Vitex doniana ameliorated some derangement observed in DMBA-induced rats.

A Tropical Lichen, Dirinaria consimilis Selectively Induces Apoptosis in MCF-7 Cells through the Regulation of p53 and Caspase-Cascade Pathway

BACKGROUND

Breast cancer is the most leading cause of death, with 49.9% of crude incidence rate and 12.9% of crude mortality rate. Natural resources have been extensively used throughout history for better and safer treatment against various diseases.

OBJECTIVES

The present study was aimed to investigate the antioxidant and anticancer potential of a tropical lichen Dirinaria consimilis (DCME) and its phytochemical analysis.

METHODS

The DCME was preliminarily evaluated for ROS, and RNS scavenging potential. Furthermore, DCME was evaluated for in vitro anticancer activity through cell proliferation assay, cell cycle analysis, annexin V/PI staining, morphological analysis, and western blotting study. Finally, the HPLC and LC-MS analyses were done to identify probable bioactive compounds.

RESULTS

The in vitro antioxidant studies showed promising ROS, and RNS scavenging potential of DCME. Moreover, the in vitro antiproliferative study bared the cytotoxic nature of DCME towards MCF-7 (IC50 - 98.58 ± 6.82μg/mL) and non-toxic towards WI-38 (IC50 - 685.85 ± 19.51μg/mL). Furthermore, the flow-cytometric analysis revealed the increase in sub G1 population as well as early apoptotic populations dose-dependently. The results from confocal microscopy showed the DNA fragmentation in MCF-7 upon DCME treatment. Finally, the western blotting study revealed the induction of tumor suppressor protein, p53, which results in increasing the Bax/Bcl-2 ratio and activation of caspase-cascade pathways.

CONCLUSION

The activation of caspase-3, -8, -9 and PARP degradation led us to conclude that DCME induces apoptosis in MCF-7 through both intrinsic and extrinsic mechanisms. The LC-MS analysis showed the presence of various bioactive compounds.

Quercetin loaded folate targeted plasmonic silver nanoparticles for light activated chemo-photothermal therapy of DMBA induced breast cancer in Sprague Dawley rats

Novel plasmonic (>800 nm) pentagonal QRC-FA-AgNPs synthesized through simple chemical technique induces light activated combined chemo-photothermal efficacy against breast cancer.

Quinazolinone derivative BNUA-3 ameliorated [NDEA+2-AAF]-induced liver carcinogenesis in SD rats by modulating AhR-CYP1B1-Nrf2-Keap1 pathway

Cytochrome P450 1B1, considered as one of the novel chemotherapeutic targets involved in cancer prevention and therapy is also associated with the conversion of procarcinogens into their active metabolites. The aryl hydrocarbon receptor (AhR) is responsible for mediating different biological responses to a wide variety of environmental pollutants and also causes transcriptional activation of cytochrome P450 enzymes including CYP1B1 and thus plays a pivotal role for initiating cancer and its progression. On the other hand, active carcinogenic metabolites and reactive oxygen species-mediated stress alter different molecular signalling pathways and gene expressions. Quinazoline derivatives are recognized for their diversified biological activities including anticancer properties. The current study was designed for evaluation of chemotherapeutic efficacy of a synthetic quinazolinone derivative BNUA-3 against hepatocellular cancer in Sprague-Dawley (SD) rats. A detailed in vivo analysis was performed by administrating BNUA-3 (15, 30 mg/kg b.w. for 28 days, i.p.) in N-Nitrosodiethylamine + 2-Acetylaminofluorene induced partially hepatectomized liver cancer in SD rats. This was followed by morphological evaluations, biochemical estimations and analysis of different mRNA and protein expressions. The results demonstrated the potency of BNUA-3 in efficient restoration of the altered morphology of liver, its protective effect against lipid peroxidation, enzymic and non-enzymic antioxidants levels in liver tissue which was disrupted after cancer induction. The study also demonstrated downregulation of AhR, CYP1B1 and Keap1 expressions with subsequent augmentation of protective Nrf2, HO-1, NQO1 and GSTA1 expressions thus, revealing the chemotherapeutic potency of BNUA-3 in inhibiting liver carcinogenesis through AhR/CYP1B1/Nrf2/Keap1 pathway.

Resveratrol represses estrogen-induced mammary carcinogenesis through NRF2-UGT1A8-estrogen metabolic axis activation

Estrogen plays a pivotal role in the pathological development of breast cancer. Resveratrol has chemo-preventive effects against breast cancer, whereas, the mechanism of antitumor activities of resveratrol remains unanswered. In this study, we showed that estrogen homeostasis profile was disturbed in both breast cancer patients and in experimental breast cancer model rats, with carcinogenic catechol estrogens significantly accumulated in the mammary tissues. UDP-glucuronosyltransferase 1A8 (UGT1A8) is an important phase II drug-metabolizing enzymes which involved in the metabolism of catechol estrogens. Here we found that the mammary nuclear factor erythroid 2-related factor 2 (NRF2) - UGT1A8 signaling was down-regulated in breast cancer rats, whereas treatment with resveratrol could upregulate the expression of NRF2 and UGT1A8, accelerate metabolic elimination of catechol estrogens, inhibit estrogen-induced DNA damage and suppress the pathological development of breast cancer. In addition, luciferase reporter assay suggested that resveratrol activated the expression of UGT1A8 by up-regulating the transcriptional activity of NRF2. Small-interfering RNA-mediated silencing of NRF2 abolished resveratrol-mediated preventive effects indicated that the antitumor effect of resveratrol is based on NRF2-UGT1A8-estrogen metabolism axis. Taken together, we established the resveratrol regulating potential on estrogen homeostasis based on NRF2-UGT1A8 signaling pathway, and also provided a novel link between estrogen glucuronidation metabolism and breast cancer pathological development.