Kang Beom Kwon

Curcumin induces apoptotic cell death of activated human CD4 + T cells via increasing endoplasmic reticulum stress and mitochondrial dysfunction

Curcumin, a natural polyphenolic antioxidant compound, exerts well-known anti-inflammatory and immunomodulatory effects, the latter which can influence the activation of immune cells including T cells. Furthermore, curcumin can inhibit the expression of pro-inflammatory cytokines and chemokines, through suppression of the NF-κB signaling pathway. The beneficial effects of curcumin in diseases such as arthritis, allergy, asthma, atherosclerosis, diabetes and cancer may be due to its immunomodulatory properties. We studied the potential of curcumin to modulate CD4+ T cells-mediated autoimmune disease, by examining the effects of this compound on human CD4+ lymphocyte activation. Stimulation of human T cells with PHA or CD3/CD28 induced IL-2 mRNA expression and activated the endoplasmic reticulum (ER) stress response. The treatment of T cells with curcumin induced the unfolded protein response (UPR) signaling pathway, initiated by the phosphorylation of PERK and IRE1. Furthermore, curcumin increased the expression of the ER stress associated transcriptional factors XBP-1, cleaved p50ATF6α and C/EBP homologous protein (CHOP) in human CD4+ and Jurkat T cells. In PHA-activated T cells, curcumin further enhanced PHA-induced CHOP expression and reduced the expression of the anti-apoptotic protein Bcl-2. Finally, curcumin treatment induced apoptotic cell death in activated T cells via eliciting an excessive ER stress response, which was reversed by the ER-stress inhibitor 4-phenylbutyric acid or transfection with CHOP-specific siRNA. These results suggest that curcumin can impact both ER stress and mitochondria functional pathways, and thereby could be used as a promising therapy in the context of Th1-mediated autoimmune diseases.

DHA blocks TPA-induced cell invasion by inhibiting MMP-9 expression via suppression of the PPAR‑γ/NF-κB pathway in MCF-7 cells

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is considered to have applications in cancer prevention and treatment. The beneficial effects of DHA against cancer metastasis are well established; however, the mechanisms underlying these effects in breast cancer are not clear. Cell invasion is critical for neoplastic metastasis, and involves the degradation of the extracellular matrix by matrix metalloproteinase (MMP)-9. The present study investigated the inhibitory effect of DHA on MMP-9 expression and cell invasion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the MCF-7 breast cancer cell line. DHA inhibited the TPA-induced activation of mitogen-activated protein kinase (MAPK) and the transcription of nuclear factor (NF)-κB, but did not inhibit the transcription of activator protein-1. DHA increased the activity of peroxisome proliferator-activated receptor (PPAR)-γ, an effect that was reversed by the application of the PPAR-γ antagonist GW9662. In addition, combined treatment with GW9662 and DHA increased NF-κB-related protein expression. These results indicate that DHA regulates MMP-9 expression and cell invasion via modulation of the MAPK signaling pathway and PPAR-γ/NF-κB activity. This suggests that DHA could be a potential therapeutic agent for the prevention of breast cancer metastasis.

Salvia miltiorrhiza extract inhibits TPA‑induced MMP‑9 expression and invasion through the MAPK/AP‑1 signaling pathway in human breast cancer MCF‑7 cells

Cancer cell invasion is crucial for metastasis. A major factor in the capacity of cancer cell invasion is the activation of matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix. Salvia miltiorrhiza has been used as a promotion for blood circulation to remove blood stasis. Numerous previous studies have demonstrated that S. miltiorrhiza extracts (SME) decrease lipid levels and inhibit inflammation. However, the mechanism behind the effect of SME on breast cancer invasion has not been identified. The inhibitory effects of SME on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 expression were assessed using western blotting, reverse transcription-quantitative polymerase chain reaction and zymography assays. MMP-9 upstream signal proteins, including mitogen-activated protein kinases and activator protein 1 (AP-1) were also investigated. Cell invasion was assessed using a matrigel invasion assay. The present study demonstrated the inhibitory effects of the SME ethanol solution on MMP-9 expression and cell invasion in TPA-treated MCF-7 breast cancer cells. SME suppressed TPA-induced MMP-9 expression and MCF-7 cell invasion by blocking the transcriptional activation of AP-1. SME may possess therapeutic potential for inhibiting breast cancer cell invasiveness.

Peucedanum japonicum Thunb. ethanol extract suppresses RANKL‑mediated osteoclastogenesis

The constituents of Peucedanum japonicum Thunb. (PJ) exhibit biological and pharmacological activities, including anti-obesity, anti-oxidant and anti-allergic activities. The aim of the present study was to examine in vitro effects of PJ in RANKL-induced signaling pathways, which determine osteoclast differentiation. PJ ethanol extract (PEE) exhibited anti-osteoporotic activity by disrupting the phospholipase C (PLC)-Ca2+-c-Fos/cAMP response element-binding protein (CREB)-nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway during osteoclastogenesis. Murine bone marrow-derived macrophages (BMMs) were cultured and used to determine the effects of PJ in the receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclastogenesis. The effects of PEE in the RANKL-mediated signaling cascade were evaluated using a standard in vitro osteoclastogenesis system. PEE treatment of BMMs significantly reduced the number of RANKL-mediated tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells (P<0.05 for 5 and 10 µg/ml PEE, P<0.01 for 25 and 50 µg/ml PEE), without cytotoxic effects. Furthermore, the expression of differentiation-related marker genes, including TRAP, Oscar, Cathepsin K, dendrocyte expressed seven transmembrane protein, ATPase H+ Transporting V0 Subunit D2 and NFATc1, were markedly suppressed. PEE induced a transient increase in free cytoplasmic Ca2+ ([Ca2+]i) mobilization via voltage-gated Ca2+ channels and PLC-sensitive pathways. Transient [Ca2+]i increase consequently resulted in the suppression of c-Fos, CREB and NFATc1 activities. These findings highlight the potential use of PJ in treating bone disorders caused by osteoclast overgrowth.