Natural products with therapeutic potential in melanoma metastasis

The identification of molecular target of (20S) ginsenoside Rh2 for its anti-cancer activity

The 20S ginsenoside Rh2 (G-Rh2) effectively inhibits cancer cell growth and survival in both animal models and cell lines. However, its molecular targets and mechanism of action remain largely unknown. By screening for molecules that interact with (20S)G-Rh2 in a phage display assay, we have identified Annexin A2 as a potential target that mediates its anti-cancer activity. Isothermal titration calorimetry and a cellular thermal shift assay demonstrated that (20S)G-Rh2 directly bound to either recombinant or intracellular Annexin A2. This binding inhibited the interaction between Annexin A2 and the NF-кB p50 subunit, which attenuated the nuclear translocations of NF-кB p50 subunit and reduced the transactivation activity of NF-кB. Correspond to this result, (20S)G-Rh2 treatment significantly down-regulated the expression of IAPs (inhibitors of apoptosis), the well-established NF-кB targets that promote cell survival. Moreover, (20S)G-Rh2 synergized with Annexin A2 inactivation to promote apoptosis. Taken together, this study for the first time suggests a cellular target and a molecular pathway by which (20S)G-Rh2 inhibits cancer cell growth. As over-expression of Annexin A2 was evident in human hepatoma, (20S)G-Rh2 might be a promising natural compound for targeted liver cancer therapy.

Assessing the anticancer effects associated with food products and/or nutraceuticals using in vitro and in vivo preclinical development-related pharmacological tests

This review is part of a special issue entitled "Role of dietary pattern, foods, nutrients and nutraceuticals in supporting cancer prevention and treatment" and describes a pharmacological strategy to determine the potential contribution of food-related components as anticancer agents against established cancer. Therefore, this review does not relate to chemoprevention, which is analysed in several other reviews in the current special issue, but rather focuses on the following: i) the biological events that currently represent barriers against the treatment of certain types of cancers, primarily metastatic cancers; ii) the in vitro and in vivo pharmacological pre-clinical tests that can be used to analyse the potential anticancer effects of food-related components; and iii) several examples of food-related components with anticancer effects. This review does not represent a catalogue-based listing of food-related components with more or less anticancer activity. By contrast, this review proposes an original pharmacological strategy that researchers can use to analyse the potential anticancer activity of any food-related component-e.g., by considering the crucial characteristics of cancer biological aggressiveness. This review also highlights that cancer patients undergoing chemotherapy should restrict the use of "food complements" without supervision by a medical nutritionist. By contrast, an equilibrated diet that includes the food-related components listed herein would be beneficial for cancer patients who are not undergoing chemotherapy.

STAT3 targeting by polyphenols: Novel therapeutic strategy for melanoma

Melanoma or malignant melanocytes appear with the low incidence rate, but very high mortality rate worldwide. Epidemiological studies suggest that polyphenolic compounds contribute for prevention or treatment of several cancers particularly melanoma. Such findings motivate to dig out novel therapeutic strategies against melanoma, including research toward the development of new chemotherapeutic and biologic agents that can target the tumor cells by different mechanisms. Recently, it has been found that signal transducer and activator of transcription 3 (STAT3) is activated in many cancer cases surprisingly. Different evidences supply the aspect that STAT3 activation plays a vital role in the metastasis, including proliferation of cells, survival, invasion, migration, and angiogenesis. This significant feature plays a vital role in various cellular processes, such as cell proliferation and survival. Here, we reviewed the mechanisms of the STAT3 pathway regulation and their role in promoting melanoma. Also, we have evaluated the emerging data on polyphenols (PPs) specifically their contribution in melanoma therapies with an emphasis on their regulatory/inhibitory actions in relation to STAT3 pathway and current progress in the development of phytochemical therapeutic techniques. An understanding of targeting STAT3 by PPs brings an opportunity to melanoma therapy. © 2016 BioFactors, 43(3):347-370, 2017.

Diet phytochemicals and cutaneous carcinoma chemoprevention: A review

Cutaneous carcinoma, which has occupied a peculiar place among worldwide populations, is commonly responsible for the considerably increasing morbidity and mortality rates. Currently available medical procedures fail to completely avoid cutaneous carcinoma development or to prevent mortality. Cancer chemoprevention, as an alternative strategy, is being considered to reduce the incidence and burden of cancers through chemical agents. Derived from dietary foods, phytochemicals have become safe and reliable compounds for the chemoprevention of cutaneous carcinoma by relieving multiple pathological processes, including oxidative damage, epigenetic alteration, chronic inflammation, angiogenesis, etc. In this review, we presented comprehensive knowledges, main molecular mechanisms for the initiation and development of cutaneous carcinoma as well as effects of various diet phytochemicals on chemoprevention.

Importance of ROS-mediated autophagy in determining apoptotic cell death induced by physapubescin B

Physapubescin B, a steroidal compound extracted from the plant Physalis pubescens L. (Solanaceae), has been reported to possess anti-cancer potential, whereas the molecular mechanism remains elusive. In this study, we first demonstrated that physapubescin B induced autophagy in human cancer cells based on the evidence that physapubescin B increased lipidation of microtubule-associated protein 1 light chain 3 (LC3) as well as number of GFP-LC3 puncta. We further examined the molecular mechanisms and found that physapubescin B enhanced the autophagic flux through promotion of reactive oxygen species (ROS)-mediated suppression of mammalian target of rapamycin complex I (mTORC1), the key negative regulator of autophagy. Additionally, excessive ROS caused by physapubescin B also induced p53-dependent apoptotic cell death. Furthermore, we provided evidence that inhibition of autophagy either by a chemical inhibitor or gene silencing promoted physapubescin B-induced apoptotic cell death, indicating that autophagy serves as a cell survival mechanism to protect cell death. Thus, our data provide a clue that inhibition of autophagy would serve as a novel strategy for enhancing the anti-cancer potential of physapubescin B.

Separation of no-carrier-added 203Pb, a surrogate radioisotope, from proton irradiated natTl2CO3 target using calcium alginate hydrogel beads

203Pb is a promising radioisotope in the field of medical science as an imaging surrogate of 212Pb. In the present investigation 203Pb was produced by proton irradiation of natural Tl2CO3 target and was separated from the bulk Tl target using calcium alginate (CA) hydrogel beads with a high separation factor (3.8×104 at 10−3 M HNO3). During the separation process 203Pb was encapsulated in CA beads and desorption of the radioisotope could only be achieved in 1M HNO3. Possibility of Tl uptake was also checked in Fe doped CA (Fe-CA) beads after oxidation of Tl(I) to Tl(III) by sodium bismuthate. No significant uptake of Tl(III) was noticed in the Fe-CA beads. The matrix is therefore suitable for isolation of 203Pb from the target as well as its storage in the bead for therapeutic as well as diagnostic purpose.

Combination of onconase and dihydroartemisinin synergistically suppresses growth and angiogenesis of non-small-cell lung carcinoma and malignant mesothelioma

Onconase (Onc) is a cytotoxic ribonuclease derived from leopard frog oocytes or early embryos, and has been applied to the treatment of malignant mesothelioma in clinics. Onc also exhibits effective growth suppression of human non-small-cell lung cancer (NSCLC). Artemisinin (Art) and its derivatives are novel antimalarial drugs that exhibit antitumor and antivirus activities. In this study, we investigated the antitumor effects of combinations of Onc and an Art derivative, dihydroartemisinin (DHA), both in vitro and in vivo Isobologram analyses showed synergistic effects on the proliferation of NSCLC cells under the treatment with Onc and DHA. In vivo experiments also showed that the antitumor effect of Onc was markedly enhanced by DHA in mouse xenograft models. No obvious adverse effect was observed after the treatment. The density of microvasculature in the tumor tissues treated with Onc/DHA combination was lower than those treated with Onc or DHA alone. The above results are consistent with the results of the matrigel plug test for angiogenesis suppression using the Onc/DHA combination. These results imply that the anti-angiogenesis effects may make important contributions to the in vivo antitumor effects of the Onc/DHA combination treatment. The Onc/DHA combination therapy may have the potential to become a novel regimen for NSCLC and mesothelioma.

LncRNA GAS5 is a critical regulator of metastasis phenotype of melanoma cells and inhibits tumor growth in vivo

The present study intended to demonstrate the effects of long noncoding RNA growth arrest-specific transcript 5 (GAS5) on the migration and invasion of melanoma cells. We first detected the expression of GAS5 among four kinds of melanoma cell lines, followed by constructing GAS5-knocked down and overexpressed stable cells. Next, we evaluated the effects of GAS5 on cell migration and invasion using wound healing and gelatin zymography assays. Finally, melanoma cells with different GAS5 expression were injected into nude mice, and the tumor volumes were recorded and tumor tissues were analyzed after sacrificing the mice. This study systematically examined the function of GAS5 in mediating melanoma metastasis and revealed that GAS5 plays an anticancer role in melanoma via regulating gelatinase A and B, both in vitro and in vivo.

Climacostol reduces tumour progression in a mouse model of melanoma via the p53-dependent intrinsic apoptotic programme

Climacostol, a compound produced by the ciliated protozoan Climacostomum virens, displayed cytotoxic properties in vitro. This study demonstrates that it has anti-tumour potential. Climacostol caused a reduction of viability/proliferation of B16-F10 mouse melanoma cells, a rapidly occurring DNA damage, and induced the intrinsic apoptotic pathway characterised by the dissipation of the mitochondrial membrane potential, the translocation of Bax to the mitochondria, the release of Cytochrome c from the mitochondria, and the activation of Caspase 9-dependent cleavage of Caspase 3. The apoptotic mechanism of climacostol was found to rely on the up-regulation of p53 and its targets Noxa and Puma. In vivo analysis of B16-F10 allografts revealed a persistent inhibition of tumour growth rate when melanomas were treated with intra-tumoural injections of climacostol. In addition, it significantly improved the survival of transplanted mice, decreased tumour weight, induced a remarkable reduction of viable cells inside the tumour, activated apoptosis and up-regulated the p53 signalling network. Importantly, climacostol toxicity was more selective against tumour than non-tumour cells. The anti-tumour properties of climacostol and the molecular events associated with its action indicate that it is a powerful agent that may be considered for the design of pro-apoptotic drugs for melanoma therapy.

The influence of the carbohydrate anomeric linkage on the free radical scavenging activity of enzymatically-synthesized phenolic glycosides

Phenolic glycosides, widely recognized for their nutraceutical properties exist in nature as α- and β-glycosides.

Diversity oriented synthesis of β-carbolinone and indolo-pyrazinone analogues based on an Ugi four component reaction and subsequent cyclisation of the resulting indole intermediate

One pot two step synthesis of β-carbolinone and indolo-pyrazinone analogues via acid mediated cyclisation of Ugi intermediate has been developed with a wide substrate scope.

Platycodin D inhibits B16F10 melanoma metastasis via antiangiogenic activity

Platycodin D inhibits B16F10 melanoma metastasisviaantiangiogenic activity.