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In the present study, we investigated the effects and molecular mechanism of marmesin, a natural coumarin compound isolated from Broussonetia kazinoki, on non-small cell lung cancer (NSCLC) cell responses and tumor angiogenesis. Marmesin abrogated mitogen-stimulated proliferation and invasion in both p53 wild-type A549 and p53-deficient H1299 NSCLC cells. These antitumor activities of marmesin were mediated by the inactivation of mitogenic signaling pathways and downregulation of cell signaling-related proteins including vascular endothelial growth factor receptor-2 (VEGFR-2), integrin β1, integrin-linked kinase and matrix metalloproteinases-2. Furthermore, marmesin suppressed the expression and secretion of VEGF in both NSCLC cells, leading to inhibition of capillary-like structure formation in human umbilical vein endothelial cells. Collectively, these findings demonstrate the pharmacological roles and molecular targets of marmesin in regulating NSCLC cell responses and tumor angiogenesis.

In the present study, we investigated the roles and molecular mechanism of 10-gingerol, a phenolic compound isolated from Zingiber officinale, in regulating cell proliferation and invasion of MDA‑MB‑231 breast cancer cells. 10-gingerol treatment inhibited cell proliferation through downregulation of cell cycle regulatory proteins such as cyclin-dependent kinases and cyclins, and subsequent induction of G1 phase arrest. In addition, 10‑gingerol treatment blocked cell invasion in response to mitogenic stimulation. These antitumor activities of 10‑gingerol were mediated through inactivation of Akt and p38MAPK activity, and suppression of epidermal growth factor receptor expression. Collectively, these findings demonstrate the pharmacological roles of 10-gingerol in regulating breast cancer cell growth and progression, and suggest further evaluation and development as a potential therapeutic agent for the prevention and treatment of breast cancer.

Integrin α3β1 is expressed on many types of cancer cells and can regulate tumor growth and progression. In the present study, we examined the roles and molecular mechanism of integrin α3β1 in modulating cell proliferation and migration of p53-deficient non-small cell lung cancer (NSCLC) cells. Reduced expression of integrin α3 by RNA silencing clearly induces cell proliferation and migration in H1299 cells, compared with those in control cells. Enhanced proliferation in integrin α3-silenced cells is mediated by upregulation and nuclear localization of cyclin-dependent kinases, and these effects require the activation of Akt and ERK as evidenced by treatment with LY294002 and PD98059, respectively. Furthermore, suppression of integrin α3 expression induces the expression of nuclear factor-κB and Bcl-2 as well as epidermal growth factor receptor, which are positively correlated with cell proliferation and survival. In contrast, increase in cell migration of integrin α3-silenced cells is found to be independent of Akt or ERK signaling pathways. Collectively, these findings suggest that integrin α3β1 plays pivotal roles in regulating cell proliferation and migration that enhance the invasive type of p53-deficient NSCLC cells.

Tetrahydrobiopterin (BH4) is known to be an essential cofactor for the aromatic amino acid hydroxylases, which are involved in the production of neurotransmitters, and for nitric oxide (NO) synthase. In the present study, we report that sepiapterin, the more stable form of the BH4 precursor, modulates ovarian cancer cell proliferation and migration by NO-dependent and -independent mechanisms. Sepiapterin induction of cell proliferation and migration in SKOV-3 cells is accompanied by ERK, Akt and p70S6K activation. These stimulatory effects of sepiapterin are reversed by pretreatment with NO synthase inhibitor. We also show that sepiapterin significantly inhibits vascular endothelial growth factor-A (VEGF-A)-stimulated cell proliferation and migration. Pretreatment with NO synthase inhibitor does not alter the ability of sepiapterin to inhibit VEGF-A-induced cell proliferation and migration, indicating that the suppressive effects of sepiapterin on VEGF-A-induced responses are mediated by a NO-independent mechanism. Finally, we demonstrate that sepiapterin markedly suppresses VEGF-A-induced p70S6K phosphorylation and VEGFR-2 expression, resulting in inhibition of VEGF-A-induced cell proliferation and migration. Collectively, these findings represent a biphasic effect of sepiapterin on cellular fates, depending on the presence of growth factors, and support further development and evaluation of sepiapterin for the treatment of cancers overexpressing VEGFR-2.