alpha-solanine and Prostatic-Neoplasms

Research over the decades has sequentially and systematically provided a near-complete resolution of multifaceted and therapeutically challenging nature of cancer. Drug discovery from plants has enjoyed a renaissance in the past few years. Natural products have provided many of the lead structures, which are currently being used as templates for the design and synthesis of novel compounds with biologically enhanced properties. With the maturity and diversification of technologies, there is a growing need to design high-throughput functional assays for the evaluation of the myriad of compounds being catalogued. This review sheds light on the tumor suppressive properties of Solanum nigrum and its bioactive ingredients. Several worthy of mention include uttroside B, solanine, solamargine, and physalins, which have been tested for efficacy in cancer cell lines and xenografted mice. We have summarized the most recent findings related to S. nigrum-mediated regulation of intracellular protein network in different cancers. α-Solanine, an active component of S. nigrum, is involved in the regulation of microRNA-21 (miRNA-21) (oncogenic) and miRNA-138 (tumor suppressor) in prostate cancer. However, this is the only available evidence that gives us a clue related to the tumor suppressive effects exerted by components of S. nigrum at a posttranscriptional level. More interestingly, S. nigrum and its components exerted inhibitory effects on different pathways including PI3K/AKT, JAK-STAT, VEGF/VEGFR, and matrix metalloproteinases in different cancers. We also provide an overview of new tools, methodologies, and approaches, which will allow researchers to extract as much information as possible out of the tremendous data sets currently being generated. The use of computational tools will be helpful in processing structurally complex natural products and also in prediction of their macromolecular targets.

Topics: Animals; Antineoplastic Agents, Phytogenic; Female; Gene Expression Regulation, Neoplastic; Hedgehog Proteins; Humans; Liver Neoplasms; Male; MicroRNAs; Oncogene Proteins; Ovarian Neoplasms; Prostatic Neoplasms; Solanine; Solanum nigrum

Radiotherapy is an adjuvant treatment of surgery in prostate cancer, while radioresistance has been the challenge of treatment. It has been reported that α-Solanine exhibits anti-cancer activity and enhances the chemo- and radio-sensitivity in several human cancers, whereas the role of α-Solanine on radiosensitivity to PCa remains to be uncovered yet. We found α-Solanine decreased cell viability in human PCa cells rather than normal prostate epithelial cells in vitro. Functional experiments showed that cell viability and colonies formation were declined & apoptosis rate and DNA double strand breaks (DSBs) marker γ-H2AX expressions were elevated by α-Solanine in PCa cells treated with X-ray irradiation, compared with X-ray irradiation treatment only. GAS5 was down-regulated & miR-18a was up-regulated in PCa cells, which was reversed in the presence of α-Solanine. Effects of ectopic GAS5 on inhibiting cell viability and survival & promoting apoptosis and DNA damage were reversed by miR-18a overexpression in PCa cells. Moreover, GAS5 regulated miR-18a expression by target binding during α-Solanine treatment. Collectively, α-Solanine suppresses cell proliferation and promotes radiosensitivity through up-regulating GAS5/miR-18a pathway in PCa. Our results provide a novel mechanism of α-Solanine treatment in human prostate cancer and help to develop a new approach to sensitizing radioresistant prostate cancer cells by targeting GAS5/miR-18a.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Gene Expression Regulation, Neoplastic; Humans; Male; MicroRNAs; Prostatic Neoplasms; Radiation Tolerance; Radiation-Sensitizing Agents; RNA, Long Noncoding; Solanine; X-Rays

α-Solanine, a naturally occurring steroidal glycoalkaloid found in nightshade (Solanum nigrum Linn.), was found to inhibit proliferation and induce apoptosis of tumor cells. However, the mechanism involved in suppression of cancer cell metastasis by α-solanine remains unclear. This study investigates the suppression mechanism of α-solanine on motility of the human prostate cancer cell PC-3. Results show that α-solanine reduces the viability of PC-3 cells. When treated with non-toxic doses of α-solanine, cell invasion is markedly suppressed by α-solanine. α-Solanine also significantly elevates epithelial marker E-cadherin expression, while it concomitantly decreases mesenchymal marker vimentin expression, suggesting it suppresses epithelial-mesenchymal transition (EMT). α-Solanine reduces the mRNA level of matrix metalloproteinase-2 (MMP-2), MMP-9 and extracellular inducer of matrix metalloproteinase (EMMPRIN), but increases the expression of reversion-inducing cysteine-rich protein with kazal motifs (RECK), and tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2. Immunoblotting assays indicate α-solanine is effective in suppressing the phosphorylation of phosphatidylinositide-3 kinase (PI3K), Akt and ERK. Moreover, α-solanine downregulates oncogenic microRNA-21 (miR-21) and upregulates tumor suppressor miR-138 expression. Taken together, the results suggest that inhibition of PC-3 cell invasion by α-solanine may be, at least in part, through blocking EMT and MMPs expression. α-Solanine also reduces ERK and PI3K/Akt signaling pathways and regulates expression of miR-21 and miR-138. These findings suggest an attractive therapeutic potential of α-solanine for suppressing invasion of prostate cancer cell.

Topics: Cadherins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Prostatic Neoplasms; Signal Transduction; Solanine; Solanum nigrum; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2