α­Solanine inhibits growth and metastatic potential of human colorectal cancer cells.

Solanum nigrum L. (Longkui) is one the most widely used anticancer herbs in traditional Chinese medicine. α­Solanine is an important ingredient of S. nigrum L. and has demonstrated anticancer properties in various types of cancer. However, the effects of α­solanine on colorectal cancer remain elusive. The aim of the present study was to assess the effects of α­solanine on human colorectal cancer cells. The results demonstrated that α­solanine inhibited the proliferation of RKO cells in a dose­ and time­dependent manner. In addition, α­solanine arrested the cell cycle at the G0/G1 phase and suppressed the expression levels of cyclin D1 and cyclin­dependent kinase 2 in RKO cells. α­Solanine induced apoptosis of RKO cells, as indicated by morphological changes and positive Annexin­FITC/propidium iodide staining. Additionally, α­solanine activated caspase­3, ­8 and ­9 in RKO cells, which contributed to α­solanine­induced apoptosis. α­Solanine also increased the generation of reactive oxygen species, which contributed to caspase activation and induction of apoptosis. α­Solanine inhibited the migration, invasion and adhesion of RKO cells, as well as the expression levels and activity of matrix metalloproteinase (MMP)­2 and MMP­9. In addition, α­solanine inhibited cell proliferation, activated caspase­3, ­8 and ­9, induced apoptosis, and inhibited the migration and invasion of HCT­116 cells. Furthermore, α­solanine inhibited tumor growth and induced apoptosis in vivo. These findings demonstrated that α­solanine effectively suppressed the growth and metastatic potential of human colorectal cancer.

Synergistic Effect of α-Solanine and Cisplatin Induces Apoptosis and Enhances Cell Cycle Arrest in Human Hepatocellular Carcinoma Cells.

AIM: The clinical application of cisplatin is limited by severe side effects associated with high applied doses. The synergistic effect of a combination treatment of a low dose of cisplatin with the natural alkaloid α-solanine on human hepatocellular carcinoma cells was evaluated. METHODS: HepG2 cells were exposed to low doses of α-solanine and cisplatin, either independently or in combination. The efficiency of this treatment modality was evaluated by investigating cell growth inhibition, cell cycle arrest, and apoptosis enhancement. RESULTS: α-solanine synergistically potentiated the effect of cisplatin on cell growth inhibition and significantly induced apoptosis. This synergistic effect was mediated by inducing cell cycle arrest at the G2/M phase, enhancing DNA fragmentation and increasing apoptosis through the activation of caspase 3/7 and/or elevating the expression of the death receptors DR4 and DR5. The induced apoptosis from this combination treatment was also mediated by reducing the expression of the anti-apoptotic mediators Bcl-2 and survivin, as well as by modulating the miR-21 expression. CONCLUSION: Our study provides strong evidence that a combination treatment of low doses of α-solanine and cisplatin exerts a synergistic anticancer effect and provides an effective treatment strategy against hepatocellular carcinoma.

Anticancer function of α-solanine in lung adenocarcinoma cells by inducing microRNA-138 expression.

Currently, lung cancer is still a main cause of malignancy-associated death worldwide. Even though various methods for prevention and treatment of lung cancer have been improved in recent decades, the 5-year survival rate has remained very low. Insights into the anticancer function of small-molecule anticancer compounds have opened our visual field about cancer therapy. α-Solanine has been well studied for its antitumor properties, but its effect in lung cancer and associated molecular mechanisms have not yet been evaluated. To explore the anticancer function of α-solanine, we performed an MTT assay, Transwell arrays, colony-forming survival assay, quantitative reverse transcription PCR (qRT-PCR), Western blotting, and dual luciferase reporter assays in A549 and H1299 cells. We found that α-solanine not only inhibited cell migration and invasion ability but also enhanced the chemosensitivity and radiosensitivity of A549 and H1299 cells. Moreover, we discovered that α-solanine could affect the expression of miR-138 and focal adhesion kinase (FAK), both of which were also found to affect the chemosensitivity and radiosensitivity of A549 and H1299 cells. In conclusion, α-solanine could affect miR-138 and FAK expression to restrict cell migration and invasion and enhance the chemosensitivity and radiosensitivity of A549 and H1299 cells. The α-solanine/miR-138/FAK cascade can probably be a potential therapy target against lung adenocarcinoma.

Effects of auxins on the production of steroidal alkaloids in rapidly proliferating tissue and cell cultures of Solanum lyratum.

INTRODUCTION: Solanum lyratum, a rare species, is used to treat cancer, tumours and warts. Plant cell and tissue culture of S. lyratum, producing steroidal alkaloids, could be useful supplements to natural sources. OBJECTIVE: To study the production of solanine, solanidine and solasodine by adding auxin-type phytohormones including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) to cell and callus cultures of S. lyratum. METHODOLOGY: Methanolic extracts were made from callus and cell cultures of S. lyratumand and analysed using RP C18 HPLC with UV detection. RESULTS: 2,4-D-induced calli from roots led to a significant enhancement in solanine production with a value of 4.13 mg/g dry weight (DW). The maximal solanidine and solasodine levels of 6.26 and 7.69 mg/g DW were respectively obtained with IBA- and IAA-treated S. lyratum cells at concentrations of 1 and 5 mg/L. CONCLUSION: Auxins were found to be useful phytohormones for the production of steroidal alkaloids. The callus and cell culture system developed is simple and can hence be a method of production of steroidal alkaloids in S. lyratum and other Solanaceae species.

Potato glycoalkaloids and metabolites: roles in the plant and in the diet.

Potatoes, members of the Solanaceae plant family, serve as major, inexpensive low-fat food sources providing energy (starch), high-quality protein, fiber, and vitamins. Potatoes also produce biologically active secondary metabolites, which may have both adverse and beneficial effects in the diet. These include glycoalkaloids, calystegine alkaloids, protease inhibitors, lectins, phenolic compounds, and chlorophyll. Because glycoalkaloids are reported to be involved in host-plant resistance and to have a variety of adverse as well as beneficial effects in cells, animals, and humans, a need exists to develop a clearer understanding of their roles both in the plant and in the diet. To contribute to this effort, this integrated review presents data on the (a) history of glycoalkaloids; (b) glycoalkaloid content in different parts of the potato plant, in processed potato products, and in wild, transgenic, and organic potatoes; (c) biosynthesis, inheritance, plant molecular biology, and glycoalkaloid-plant phytopathogen relationships; (d) dietary significance with special focus on the chemistry, analysis, and nutritional quality of low-glycoalkaloid potato protein; (e) pharmacology and toxicology of the potato glycoalkaloids comprising alpha-chaconine and alpha-solanine and their hydrolysis products (metabolites); (f) anticarcinogenic and other beneficial effects; and (g) possible dietary consequences of concurrent consumption of glycoalkaloids and other biologically active compounds present in fresh and processed potatoes. An enhanced understanding of the multiple and overlapping aspects of glycoalkaloids in the plant and in the diet will benefit producers and consumers of potatoes.