Background/Aim: Piperine is a major pungent alkaloid present in black pepper (Piper nigrum L). This study investigated the potential anticancer effects of piperine on human melanoma cells and explored the potential pharmacological mechanisms in vitro and in vivo. Materials and Methods: Studies were performed using the MTT assay,4', staining, western blotting, a xenograft model, the terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and immunohistochemistry. Results: Piperine inhibited the growth of melanoma cells. Several apoptotic events were observed following treatment, as revealed by DAPI staining. Piperine increased the expression of BCL2-associated X, apoptosis regulator (BAX), cleaved poly(ADP-ribose)polymerase, cleaved caspase-9, phospho-c-Jun N-terminal kinase and phospho-p38, and reduced that of B-cell lymphoma 2 (BCL2), X-chromosome-linked inhibitor of apoptosis, and phosphoextracellular signal-regulated protein kinase (ERK1/2) in a concentration-dependent manner. Treatment of mice for 4 weeks with piperine inhibited tumor growth without apparent toxicity. Piperine increased the expression of apoptotic cells and cleaved-caspase-3 protein and reduced the expression of phospho-ERK1/2 protein in melanoma tumors. Conclusion: Piperine suppressed the growth of human melanoma cells by the induction of apoptosis via the inhibition of tumor growth of human melanoma cells and tumor xenograft models.The mortality rate of cancer is increasing every year worldwide. Cancer is also the leading cause of death in South Korea (1, 2). The occurrence of skin cancer has consistently increased with concurrent increases in ultraviolet light exposure during outdoor activities. Comprising only 4% of all types of skin cancers, but with a mortality as high as 80%, melanoma has the highest rate of skin cancer malignancies and is caused by the malignant alteration of melanin cells (3,4). Malignant human melanoma cells rapidly spread to internal organs such as the bones, liver and lungs through lymphatic ducts and blood vessels. Due to its high resistance to chemotherapy and radiotherapy, surgical excision after early detection is considered the only treatment for this disease. Human melanoma is an intractable disease, and no specific treatment is available in cases of recurrence (5,6). A specific group of food materials, medications, and health supplements developed from various natural resources have also been used to treat melanoma (7).Piper nigrum L., a member of the family Piperaceae, is used as spice in Asia and India, and has beneficial effects on dyspepsia and pain relief due to the presence of various phytochemicals with different biological activities (8). Piperine (Figure 1) is a major alkaloid-amide that is responsible for the distinct taste and scent of pepper (9). Piperine also reportedly has various biological activities including antioxidant (10), anti-inflammatory (11), antiarthritic (12), antibacterial (13), and anticancer (14).

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Summary. We investigated the phenotypic changes of human umbilical cord blood (CB) CD34þ cells during ex vivo expansion using thrombopoietin (TPO), flt3-ligand (FL), and/or granulocyte-colony stimulating factor (G-CSF). During ex vivo expansion of CD34 þ cells isolated from human CB for up to 5 weeks, surface expression of molecules on the cultured cells including CD64 (FcgRI), CD32 (FcgRII), CD16 (FcgRIII), CD11b (MAC-1) and CD18 (b 2 -integrin) was analysed by flow cytometry along with simultaneous measurement of apoptosis by 7-aminoactinomycin D staining method. CD64, CD32 and/or CD18 expressing cells appeared in the cultures both with and without the addition of G-CSF until the tenth day. However, without G-CSF, CD16þ fractions did not appear and CD11b þ fractions were not maintained. With G-CSF, the CD16 þ or CD11b þ fractions appeared only from the second week. These results suggest that G-CSF is necessary for the late stage of myeloid maturation during which CD16 and CD11b are expressed.

Shikonin, a natural product isolated from the roots of Lithospermum erythrorhizon, exhibits pharmacological effects against inflammation, ulcers, infections, and tumors. In the present study, we aimed to investigate the antitumor effects of shikonin on the human melanoma cell line, A375SM, and in an in vivo mouse xenograft model. We examined the anticancer effects of shikonin by in vitro experiments (MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, 4′,6-diamidino-2-phenylindole (DAPI) stain, annexin V/ propidium iodide (PI) stain, and protein analysis of apoptosis and mitogen-activated protein kinase (MAPK) pathways). Further, the anticancer effect in vivo was confirmed through a xenograft model. Our results showed that shikonin inhibited the proliferation of melanoma cells in a dose-dependent manner. In addition, shikonin significantly increased nucleus and chromatin condensation and early/late apoptosis. Shikonin also increased the pro-apoptotic proteins and decreased the anti-apoptotic proteins. Additionally, shikonin was overexpressed in MAPK pathways. Investigation of the effects of shikonin in a mouse xenograft model not only showed decreased A375SM tumor volume but also increased apoptosis as determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Furthermore, pathologic changes were not observed in the liver and kidney of mice. Collectively, the study indicated that shikonin inhibited the proliferation of the human melanoma cells by inducing apoptosis, mediated by MAPK pathway and that it is a potential candidate for an anticancer drug against melanoma cancer.