Recent progress in natural dietary non-phenolic bioactives on cancers metastasis

Alkaloids in Cancer therapy: Targeting the tumor microenvironment and metastasis signaling pathways

The use of phytomedicine in cancer therapy is a growing field of research that takes use of the medicinal properties of plant-derived compounds. Under the domain of cancer therapy and management, alkaloids, a prominent group of natural compounds, have showed significant potential. Alkaloids often affect a wide range of essential cellular mechanisms involved in cancer progression. These multi-targeting capabilities, can give significant advantages to alkaloids in overcoming resistance mechanisms. For example, berberine, an alkaloid found in Berberis species, is widely reported to induce apoptosis by activating caspases and regulating apoptotic pathways. Notably, alkaloids like as quinine have showed promise in inhibiting the formation of new blood vessels required for tumor growth. In addition, alkaloids have shown anti-proliferative and anticancer properties mostly via modulating key signaling pathways involved in metastasis, including those regulating epithelial-mesenchymal transition. This work provides a comprehensive overview of naturally occurring alkaloids that exhibit anticancer properties, with a specific emphasis on their underlying molecular mechanisms of action. Furthermore, many methods to modify previously reported difficult physicochemical properties using nanocarriers in order to enhance its systemic bioavailability have been discussed as well. This study also includes information on newly discovered alkaloids that are now being studied in clinical trials for their potential use in cancer treatment. Further, we have also briefly mentioned on the application of high-throughput screening and molecular dynamics simulation for acceleration on the identification of potent alkaloids based compounds to target and treat cancer.

Nanomaterials in anticancer applications and their mechanism of action - A review

The current challenges in cancer treatment using conventional therapies have made the emergence of nanotechnology with more advancements. The exponential growth of nanoscience has drawn to develop nanomaterials (NMs) with therapeutic activities. NMs have enormous potential in cancer treatment by altering the drug toxicity profile. Nanoparticles (NPs) with enhanced surface characteristics can diffuse more easily inside tumor cells, thus delivering an optimal concentration of drugs at tumor site while reducing the toxicity. Cancer cells can be targeted with greater affinity by utilizing NMs with tumor specific constituents. Furthermore, it bypasses the bottlenecks of indiscriminate biodistribution of the antitumor agent and high administration dosage. Here, we focus on the recent advances on the use of various nanomaterials for cancer treatment, including targeting cancer cell surfaces, tumor microenvironment (TME), organelles, and their mechanism of action. The paradigm shift in cancer management is achieved through the implementation of anticancer drug delivery using nano routes.

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.

ε-Viniferin and α-viniferin alone or in combination induced apoptosis and necrosis in osteosarcoma and non-small cell lung cancer cells

This study investigated the effects and molecular mechanisms of ε-viniferin and α-viniferin in non-small cell lung cancer cell line A549, melanoma cell line A2058, and osteosarcoma cell lines HOS and U2OS. Results showed ε-viniferin having antiproliferative effects on HOS, U2OS, and A549 cells. Compared with ε-viniferin at the same concentration, α-viniferin had higher antiproliferative effects on HOS cells, but not the same effect on U2OS and A549 cells. Lower dose combination of α-viniferin and ε-viniferin had more synergistic effects on A549 cells than either drug alone. α-Viniferin induced apoptosis in HOS cells by decreasing expression of phospho-c-Jun-N-terminal kinase 1/2 (p-JNK1/2) and increasing expression of cleaved Poly (ADP-ribose) polymerase (PARP), whereas α-viniferin in combination with ε-viniferin induced apoptosis in A549 cells by decreasing expression of phospho-protein kinase B (p-AKT) and increasing expression of cleaved PARP and cleaved caspase-3. ε-Viniferin and α-viniferin have not been studied using in vivo tumor models for cancer. This research is the first showing that ε-viniferin treatment resulted in significant inhibition of tumor growth in A549-cell xenograft-bearing nude mice compared with the control group. Consequently, ε-viniferin and α-viniferin may prove to be new approaches and effective therapeutic agents for osteosarcoma and lung cancer treatment.

Chemical composition and cytotoxic activity of the essential oil from the aerial parts of Dorema aucheri

Introduction: Herbal products are beneficial compounds with many applications in human life. In this study the chemical composition and cytotoxic activity of the essential oil of the aerial parts of Dorema aucheri were assessed. Methods: The essential oil was extracted by hydrodistillation after drying the aerial parts of D. aucheri, collected from the mountains around Yasuj city in the South-West of Iran. The oil composition was determined by GC/MS. To evaluate in vitro cytotoxic activity, the apoptotic effects of the essential oil were investigated against SW48 and SW1116 colorectal cancer cell lines by (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium) bromide (MTT) assay and flow cytometry. Results: The essential oil yield was obtained 0.02% (W/W). Twenty-five compounds were identified in the oil, and the main constituents were caryophyllene (E) (31.29%), Phytol (14.92%), gurjunene (β-) (9.84%), 3,7,11,15-tetramethyl-2-hexadecen-1-ol (8.7%), and n-hexadecanoic acid (8.09%). The MTT assay showed that the IC50 values of the essential oil for SW48 and SW1116 cell lines were 1.4 and 1.2 mg/mL, respectively. The results of flow cytometry showed that the essential oil significantly increased the apoptosis in SW48 cell line compared with the vincristine (P < 0.05). It also increased the apoptosis in SW1116 cells compared with the vincristine, but this difference is not significant. Conclusion: The essential oil of D. aucheri consisted of high amounts of caryophyllene and showed significant cytotoxic effects against SW48 and SW1116 cancerous cell lines.

Advances in Azorella glabra Wedd. Extract Research: In Vitro Antioxidant Activity, Antiproliferative Effects on Acute Myeloid Leukemia Cells and Bioactive Compound Characterization

Azorella glabra Wedd. (AG) is traditionally used to treat gonorrhea or kidney’s problems. The antioxidant, antidiabetic, anticholinesterase and in vitro antitumor activities of AG extracts were recently reported. The aim of this work was to investigate anti-leukemic properties of AG chloroform fraction (AG CHCl₃) and of its ten sub-fractions (I-X) and to identify their possible bioactive compounds. We determined their in vitro antioxidant activity using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), nitric oxide (NO) and superoxide anion (SO) assays, and their phytochemical profile by spectrophotometric and LC-MS/MS techniques. I-X action on two acute myeloid leukemia (AML) cell lines viability, apoptosis and cell cycle were evaluated by MTS, western blotting and cytofluorimetric assays. Different polyphenol, flavonoid and terpenoid amount, and antioxidant activity were found among all samples. Most of I-X induced a dose/time dependent reduction of cell viability higher than parent extract. IV and VI sub-fractions showed highest cytotoxic activity and, of note, a negligible reduction of healthy cell viability. They activated intrinsic apoptotic pathway, induced a G₀/G₁ block in leukemic cells and, interestingly, led to apoptosis in patient AML cells. These activities could be due to mulinic acid or azorellane terpenoids and their derivatives, tentatively identified in both IV and VI. In conclusion, our data suggest AG plant as a source of potential anti-AML agents.

Chemopreventive Effect of β-Cryptoxanthin on Human Cervical Carcinoma (HeLa) Cells Is Modulated through Oxidative Stress-Induced Apoptosis

The present study was aimed to assess cellular and molecular events involved in the chemopreventive activities of β-cryptoxanthin derived from mandarin oranges (Citrus unshiu Marc.) on human cervical carcinoma (HeLa) cells. In vitro experiments established that β-cryptoxanthin significantly inhibited the proliferation of HeLa cells with the IC₅₀ value of 4.5 and 3.7 µM after 24 and 48 h of treatments, respectively. β-cryptoxanthin-treated HeLa cells exhibited enhanced levels of oxidative stress correlated with significant downregulation of anti-apoptotic Bcl-2, and upregulation of pro-apoptotic Bax mRNA expression. Moreover, β-cryptoxanthin triggered nuclear condensation and disruption of the integrity of the mitochondrial membrane, upregulated caspase-3, -7, and -9 mRNA, and enhanced activation of caspase-3 proteins, resulting in nuclei DNA damage and apoptosis of HeLa cells. Remarkably, TUNEL assay carried out to detect nuclei DNA damage showed 52% TUNEL-positive cells after treatment with a physiological concentration of β-cryptoxanthin (1.0 μM), which validates its potential as an anticancer drug of natural origin.

Dietary Flavonoids Luteolin and Quercetin Inhibit Migration and Invasion of Squamous Carcinoma through Reduction of Src/Stat3/S100A7 Signaling

Flavonoids are well-known antioxidants and have shown the ability to prevent tumor formation and recurrence. Especially in dietary flavonoids, they have provided convenience and consistence of intake for long-term prevention of tumor formation. Previous reports suggested that S100 calcium-binding protein A7 (S100A7) might activate epithelial–mesenchymal transition (EMT) signaling and promote the metastasis of tumor cells; however, the regulatory signaling was unclear. In this study, we found that S100A7 was highly expressed in cancer cells and could be reduced by luteolin (Lu) and quercetin (Qu) through Src/Stat3 signaling. We found that the protein levels of S100A7, phosphorylated Src (p-Src), and p-Stat3 were increased in A431-III cells. Flavonoids Lu and Qu reduce protein levels of p-Src, p-Stat3 and S100A7 in A431-III cells. Treatment of A431-III cells with Src inhibitor SU6656 and Stat3 inhibitor S3I-201 also reduced the protein levels of S100A7. Transactivation activity of 5′-upstream regions of S100A7 was activated by Stat3 but was reduced by treatment with Lu, Qu, SU6656 and S3I-201. The treatment also reduced the migratory and invasive abilities of A431-III cells. In a further analysis of EMT markers, the protein level of E-cad increased and that of Twist decreased after treatment with the inhibitors and flavonoids. Overexpression of S100A7 decreased the protein level of E-cad and increased the Twist level, whereas knockdown of S100A7 had the opposite effects. Treatment with S3I-201, Lu and Qu, compared to the control, were found to decrease metastasis of tumor cells in zebrafish larvae. These results suggest that Lu and Qu may inhibit Src/Stat3/S100A7 signaling to reduce tumorigenesis of cancer cells.

Comparison between tumors in plants and human beings: Mechanisms of tumor development and therapy with secondary plant metabolites

BACKGROUND

Human tumors are still a major threat to human health and plant tumors negatively affect agricultural yields. Both areas of research are developing largely independent of each other. Treatment of both plant and human tumors remains unsatisfactory and novel therapy options are urgently needed.

HYPOTHESIS

The concept of this paper is to compare cellular and molecular mechanisms of tumor development in plants and human beings and to explore possibilities to develop novel treatment strategies based on bioactive secondary plant metabolites. The interdisciplinary discourse may unravel commonalities and differences in the biology of plant and human tumors as basis for rational drug development.

RESULTS

Plant tumors and galls develop upon infection by bacteria (e.g. Agrobacterium tumefaciens and A. vitis, which harbor oncogenic T-DNA) and by insects (e.g. gall wasps, aphids). Plant tumors are benign, i.e. they usually do not ultimately kill their host, but they can lead to considerable economic damage due to reduced crop yields of cultivated plants. Human tumors develop by biological carcinogenesis (i.e. viruses and other infectious agents), chemical carcinogenesis (anthropogenic and non-anthropogenic environmental toxic xenobiotics) and physical carcinogenesis (radioactivity, UV-radiation). The majority of human tumors are malignant with lethal outcome. Although treatments for both plant and human tumors are available (antibiotics and apathogenic bacterial strains for plant tumors, cytostatic drugs for human tumors), treatment successes are non-satisfactory, because of drug resistance and the severe adverse side effects. In human beings, attacks by microbes are repelled by cellular immunity (i.e. innate and acquired immune systems). Plants instead display chemical defense mechanisms, whereby constitutively expressed phytoanticipin compounds compare to the innate human immune system, the acquired human immune system compares to phytoalexins, which are induced by appropriate biotic or abiotic stressors. Some chemical weapons of this armory of secondary metabolites are also active against plant galls. There is a mutual co-evolution between plant defense and animals/human beings, which was sometimes referred to as animal plant warfare. As a consequence, hepatic phase I-III metabolization and excretion developed in animals and human beings to detoxify harmful phytochemicals. On the other hand, plants invented "pro-drugs" during evolution, which are activated and toxified in animals by this hepatic biotransformation system. Recent efforts focus on phytochemicals that specifically target tumor-related mechanisms and proteins, e.g. angiogenic or metastatic inhibitors, stimulators of the immune system to improve anti-tumor immunity, specific cell death or cancer stem cell inhibitors, inhibitors of DNA damage and epigenomic deregulation, specific inhibitors of driver genes of carcinogenesis (e.g. oncogenes), inhibitors of multidrug resistance (i.e. ABC transporter efflux inhibitors), secondary metabolites against plant tumors.

CONCLUSION

The exploitation of bioactive secondary metabolites to treat plant or human tumors bears a tremendous therapeutic potential. Although there are fundamental differences between human and plant tumors, either isolated phytochemicals and their (semi)synthetic derivatives or chemically defined and standardized plant extracts may offer new therapy options to decrease human tumor incidence and mortality as well as to increase agricultural yields by fighting crown galls.

Small Molecular Leads Differentially Active Against HER2 Positive and Triple Negative Breast Cancer Cell Lines

Background:

Breast cancer is the most prevalent cancer type in women globally. It is characterized by distinct subtypes depending on different gene expression patterns. Oncogene HER2 is expressed on the surface of cell and is responsible for cell growth regulation. Increase in HER2 receptor protein due to gene amplification, results in aggressive growth, and high metastasis in cancer cells.

Methods:

The current study evaluates and compares the anti-breast cancer effect of commercially available compounds against HER2 overexpressing BT-474, and triple negative MDA-MB-231 breast cancer cell lines.

Results:

Preliminary in vitro cell viability assays on these cell lines identified 6 lead molecules active against breast cancer. Convallatoxin (4), a steroidal lactone glycoside, showed the most potent activity with IC50 values of 0.63 ± 0.56, and 0.69 ± 0.59 µM against BT-474 and MDA-MB-231, respectively, whereas 4-[4-(Trifluoromethyl)-phenoxy] phenol (3) a phenol derivative, and Reserpine (5) an indole alkaloid selectively inhibited the growth of BT-474, and MDA-MB-231 breast cancer cells, respectively.

Conclusion:

These results exhibited the potential of small molecules in the treatment of HER2 amplified and triple negative breast cancers in vitro.

Use of Nutraceuticals in Angiogenesis-Dependent Disorders

The term of angiogenesis refers to the growth of new vessels from pre-existing capillaries. The phenomenon is necessary for physiological growth, repair and functioning of our organs. When occurring in a not regulated manner, it concurs to pathological conditions as tumors, eye diseases, chronic degenerative disorders. On the contrary insufficient neovascularization or endothelial disfunction accompanies ischemic and metabolic disorders. In both the cases an inflammatory and oxidative condition exists in supporting angiogenesis deregulation and endothelial dysfunction. The use of nutraceuticals with antioxidant and anti-inflammatory activities can be a therapeutic option to maintain an adequate vascularization and endothelial cell proper functioning or to blunt aberrant angiogenesis. A revision of the updated literature reports on nutraceuticals to guide endothelial cell wellness and to restore physiological tissue vascularization is the objective of this paper. The critical aspects as well as lacking data for human use will be explored from a pharmacological perspective.