Cancer stem cells (CSCs) have been identified in almost all cancers and give rise to metastases and can also act as a reservoir of cancer cells that may cause a relapse after surgery, radiation, or chemotherapy. Thus they are obvious targets in therapeutic approaches and also a great challenge in cancer treatment. The threat presented by CSCs lies in their unlimited proliferative ability and multidrug resistance. These findings have necessitated an effective novel strategy to target CSCs for cancer treatment. Nanomaterials are on the route to providing novel methods in cancer therapies. Although, there have been a large number of excellent work in the field of targeted cancer therapy, it remains an open question how nanomaterials can meet future demands for targeting and eradicating of CSCs. In this review, we summarized recent and highlighted future prospects for targeting CSCs for cancer therapies by using a variety of nanomaterials.
Insulin resistance and type 2 diabetes mellitus are associated with impaired postprandial secretion of glucagon-like peptide-1 (GLP-1), a potent insulinotropic hormone. The direct effects of insulin and insulin resistance on the L cell are unknown. We therefore hypothesized that the L cell is responsive to insulin and that insulin resistance impairs GLP-1 secretion. The effects of insulin and insulin resistance were examined in well-characterized L cell models: murine GLUTag, human NCI-H716, and fetal rat intestinal cells. MKR mice, a model of chronic hyperinsulinemia, were used to assess the function of the L cell in vivo. In all cells, insulin activated the phosphatidylinositol 3 kinase-Akt and MAPK kinase (MEK)-ERK1/2 pathways and stimulated GLP-1 secretion by up to 275 +/- 58%. Insulin resistance was induced by 24 h pretreatment with 10(-7) m insulin, causing a marked reduction in activation of Akt and ERK1/2. Furthermore, both insulin-induced GLP-1 release and secretion in response to glucose-dependent insulinotropic peptide and phorbol-12-myristate-13-acetate were significantly attenuated. Whereas inhibition of phosphatidylinositol 3 kinase with LY294002 potentiated insulin-induced GLP-1 release, secretion was abrogated by inhibiting the MEK-ERK1/2 pathway with PD98059 or by overexpression of a kinase-dead MEK1-ERK2 fusion protein. Compared with controls, MKR mice were insulin resistant and displayed significantly higher fasting plasma insulin levels. Furthermore, they had significantly higher basal GLP-1 levels but displayed impaired GLP-1 secretion after an oral glucose challenge. These findings indicate that the intestinal L cell is responsive to insulin and that insulin resistance in vitro and in vivo is associated with impaired GLP-1 secretion.
Cancer metastasis is a primary cause of cancer death. Hispolon is an active phenolic compound of Phellinus linteus, a mushroom that has recently been shown to have antioxidant and anticancer activities. In this study, we first observed that hispolon exerted a dose-dependent inhibitory effect on invasion and motility, but not on adhesion, of the highly metastatic SK-Hep1 cells in the absence of cytotoxicity. Mechanistically, hispolon decreased the expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-plasminogen activator (uPA) in a concentration-dependent manner. Hispolon also inhibited phosphorylation of extracellular signaling-regulating kinase1/2 (ERK1/2), phosphatidylinositol-3-kinase/serine/threonine protein kinase (or protein kinase B (PI3K/Akt), and focal adhesion kinase (FAK). Furthermore, treatment of SK-Hep1 cells with an inhibitor specific for ERK1/2 (PD98256) decreased the expression of MMP-2, and MMP-9. These results demonstrate that hispolon can inhibit the metastasis of SK-Hep1 cells by reduced expression of MMP-2, MMP-9, and uPA through the suppression of the FAK signaling pathway and of the activity of PI3K/Akt and Ras homologue gene family, member A (RhoA). These findings suggest that hispolon may be used as an antimetastatic agent.
Ergostatrien-3β-ol (ST1), an active and major ingredient from Antrodia camphorata (AC) submerged whole broth was evaluated for the analgesic and anti-inflammatory effects. Treatment of male imprinting control region (ICR) mice with ST1 (1, 5, and 10 mg/kg) significantly inhibited the numbers of acetic-acid-induced writhing response in 10 min. Also, our result showed that ST1 (10 mg/kg) significantly inhibited the formalin-induced pain in the late phase (p < 0.001). In the anti-inflammatory test, ST1 (10 mg/kg) decreased the paw edema at 4 and 5 h after λ-carrageenin (Carr) administration and increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver tissue. We also demonstrated that ST1 significantly attenuated the malondialdehyde (MDA) level in the edema paw at 5 h after Carr injection. ST1 (1, 5, and 10 mg/kg) decreased the nitric oxide (NO) levels on both the edema paw and serum level at 5 h after Carr injection. Also, ST1 (5 and 10 mg/kg) diminished the serum tumor necrosis factor (TNF-R) at 5 h after Carr injection. Western blotting revealed that ST1 (10 mg/kg) decreased Carr-induced inducible nitric oxide synthase (iNOS), and cycloxyclase (COX-2) expressions at 5 h in the edema paw. An intraperitoneal (ip) injection treatment with ST1 also diminished neutrophil infiltration into sites of inflammation, as did indomethacin (Indo). The anti-inflammatory mechanisms of ST1 might be related to the decrease in the level of MDA, iNOS, and COX-2 in the edema paw via increasing the activities of CAT, SOD, and GPx in the liver through the suppression of TNF-R and NO.
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