Gleditsia sinensis thorns (GST) have been used as a traditional medicine for carbuncles and skin diseases. The purpose of this study was to decide whether non-toxicological levels of water extract of GST (WEGST) are effective in inhibiting the progress of prostate cancer formation and to identify the target molecule involved in the WEGST-mediated inhibitory process of prostate cancer cell migration and in vivo tumor formation. Through the Boyden chamber migration assay, we found that non-toxic levels of WEGST could not attenuate the PC3 migration to the bottom area coated with serum but significantly inhibited PC3 cell migration to the collagen-coated bottom area. We also found that non-toxic levels of WEGST significantly attenuated collagen against adhesion. Interestingly, ectopic administration of WEGST could not affect the expression of α2β1 integrin, which is known as a receptor of collagen. However, when the PC3 cells adhered to a collagen-coated plate, the expression of α2 integrin but not that of β1 integrin was significantly inhibited by the administration of non-toxic levels of WEGST, leading to the inhibition of focal adhesion kinase (FAK) phosphorylation. Furthermore, oral administration of WEGST (25 mg/kg/day) significantly inhibited the size of a PC3 cell-xenografted tumor. Taken together, these results suggest a novel molecular mechanism for WEGST to inhibit prostate cancer progression at particular stages, such as collagen-mediated adhesion and migration, and it might provide further development for the therapeutic use of WEGST in the treatment of prostate cancer progression.

Smilax glabra Roxb. (SGR) has been used as a traditional medicine for brucellosis and syphilis. In this study, we investigated whether nontoxicological levels of water extract of SGR (WESGR) are effective for suppressing steps in the progression of prostate cancer, such as collagen-mediated migration and adhesion and identified the target molecule responsible for such effects. We found that nontoxicological levels of WESGR did not attenuate PC3 and LNCaP cell adhesion to serum but did significantly do so with collagen. In addition, using the Boyden chamber assay, we found that nontoxicological levels of WESGR did not inhibit the migration of PC3 and LNCaP cells to a serum-coated area but did significantly attenuate migration to a collagen-coated area. Interestingly, the expression of α2β1 integrin, a known receptor of collagen, was not affected by ectopic administration of WESGR. However, WESGR significantly attenuated the expression of β1 integrin, but not α2 integrin when PC3 and LNCaP cells were placed on a collagen-coated plate, resulting in attenuation of focal adherent kinase phosphorylation. Finally, 5-O-caffeoylquinic acid was determined as a functional single component which is responsible for antiprostate cancer effects of WESGR. Taken together, our results suggest a novel molecular mechanism for WESGR-mediated antiprostate cancer effects at particular steps such as with migration and adhesion to collagen, and it could provide the possibility of therapeutic use of WESGR against prostate cancer progression.

Free radicals formed in the inner ear in response to high-intensity noise, are regarded as detrimental factors for noise-induced hearing loss (NIHL). We reported previously that intraperitoneal injection of cobalt chloride attenuated the loss of sensory hair cells and NIHL in mice. The present study was designed to understand the preconditioning effect of CoCl₂ on oxidative stress-mediated cytotoxicity. Treatment of auditory cells with CoCl₂ promoted cell proliferation, with increases in the expressions of two redox-active transcription factors (hypoxia-inducible factor 1α, HIF-1α, nuclear factor erythroid 2-related factor 2; Nrf-2) and an antioxidant enzyme (peroxiredoxin 6, Prdx6). Hydrogen peroxide treatment resulted in the induction of cell death and reduction of these protein expressions, reversed by pretreatment with CoCl₂. Knockdown of HIF-1α or Nrf-2 attenuated the preconditioning effect of CoCl₂. Luciferase reporter analysis with a Prdx6 promoter revealed transactivation of Prdx6 expression by HIF-1α and Nrf-2. The intense immunoreactivities of HIF-1α, Nrf-2, and Prdx6 in the organ of Corti (OC), spiral ganglion cells (SGC), and stria vascularis (SV) of the cochlea in CoCl₂-injected mice suggested CoCl₂-induced activation of HIF-1α, Nrf-2, and Prdx6 in vivo. Therefore, we revealed that the protective effect of CoCl₂ is achieved through distinctive signaling mechanisms involving HIF-1α, Nrf-2, and Prdx6.

Epithelial–mesenchymal transition (EMT) has been implicated in cancer progression, invasion, and metastasis. We aimed to evaluate the correlations between clinicopathological characteristics and EMT markers in patients with hepatocellular carcinoma (HCC) who underwent surgical resection and to identify the key regulator in EMT process. Fresh-frozen HCC tissues and adjacent nontumor liver tissues from 30 patients who underwent surgical resection were provided by the Gachon University Gil Medical Center Bio Bank. Human HCC cell lines, Hep3B, SNU449, and Huh7 cells were transfected with Rac1 siRNA and exposed to hypoxic conditions. The combined EMT markers expression (down-expression of E-cadherin and overexpression of p21-activated kinases 1 (PAK1)/Snail) by Western blot in HCC tissues when compared to adjacent nontumor liver tissues was significantly associated with macrovascular invasion (p = 0.021), microvascular invasion (p = 0.001), large tumor size (p = 0.021), and advanced tumor stage (p = 0.015). Patients with combined EMT markers expression showed early recurrence and poor overall survival. In vitro studies showed that Rac1 knockdown decreased the expression of EMT markers including PAK1 and Snail in hypoxia-induced Hep3B cells and suppressed the migration and invasion of hypoxia-induced HCC cells. Rac1 may be a potential therapeutic target for inhibition of EMT process through the inhibition of PAK1 and Snail in HCC.