Recent reports suggest that hypoxia inducible factor-2α (HIF-2α) is a key regulator of osteoarthritis cartilage destruction. However, the precise role of HIF-2α in the inflammatory response and osteoclast differentiation remains unclear. The purpose of this study was to investigate the effect of HIF-2α on inflammatory cytokines, extracellular matrix (ECM) destruction enzymes, and osteoclastic differentiation in nicotine and lipopolysaccharide (LPS)-stimulated human periodontal ligament cells (PDLCs). HIF-2α was upregulated in chronically inflamed PDLCs of periodontitis patients, and in nicotine- and LPS-exposed PDLC in dose- and time-dependent manners. HIF-2α inhibitor and HIF-2α siRNA attenuated the nicotine- and LPS- induced production of NO and PGE2 , upregulation of iNOS, COX-2, pro-inflammatory cytokines (IL-1β, TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-11, and IL-17), and matrix metalloproteinases (MMPs; MMP-1, -8, -13, -2 and -9), and reversed the effect on TIMPs (TIMP-1 and -2) in PDLCs. The conditioned medium produced by nicotine and LPS-treated PDLCs increased the number of TRAP-stained osteoclasts, TRAP activity and osteoclast-specific genes, which has been blocked by HIF-2α inhibition and silencing. HIF-2α inhibitor and HIF-2α siRNA inhibited the effects of nicotine and LPS on the activation of Akt, JAK2 and STAT3, ERK and JNK MAPK, nuclear factor-κB, c-Jun, and c-Fos. Taken together, this study is the first to demonstrate that HIF-2α inhibition exhibits anti-inflammatory activity through the inhibition of inflammatory cytokines and impairment of ECM destruction, as well as blocking of osteoclastic differentiation in a nicotine- and periodontopathogen-stimulated PDLCs model. Thus, HIF-2α inhibition may be a novel molecular target for therapeutic approaches in periodontitis.

Although previous studies have shown that mollugin, a bioactive phytochemical isolated from Rubia cordifolia L. (Rubiaceae), exhibits antitumor effects, its biological activity in oral cancer has not been reported. We thus investigated the effects and putative mechanism of apoptosis induced by mollugin in human oral squamous cell carcinoma cells (OSCCs). Results show that mollugin induces cell death in a dose-dependent manner in primary and metastatic OSCCs. Mollugin-induced cell death involved apoptosis, characterized by the appearance of nuclear shrinkage, flow cytometric analysis of sub-G1 phase arrest, and annexin V-FITC and propidium iodide staining. Western blot analysis and RT-PCR revealed that mollugin suppressed activation of NF-κB and NF-κB-dependent gene products involved in antiapoptosis (Bcl-2 and Bcl-xl), invasion (MMP-9 and ICAM-1), and angiogenesis (FGF-2 and VEGF). Furthermore, mollugin induced the activation of p38, ERK, and JNK and the expression of heme oxygenase-1 (HO-1) and nuclear factor E2–related factor 2 (Nrf2). Mollugin-induced growth inhibition and apoptosis of HO-1 were reversed by an HO-1 inhibitor and Nrf2 siRNA. Collectively, this is the first report to demonstrate the effectiveness of mollugin as a candidate for a chemotherapeutic agent in OSCCs via the upregulation of the HO-1 and Nrf2 pathways and the downregulation of NF-κB.

The objective of this study was to compare the anticancer activity of glucosinolates against four different cancer cells; SNU-251, SNU-354, SNU-C4, MCF-7 and to determine the amounts of glucosinolates in mustard leaves. Green and red mustard leaves were cultivated on the field of Rural Development Administration from May to July, 2010. After the leaves were harvest and lypophilized, the fine powder was extracted with boiling 70% methanol(v/v) for the measurement of anticancer activity and then applied to the cancer cells obtained from Korean Cell Line Bank(KCLB). The anticancer activity of red leaf mustard was higher than that of green mustard leaf, particularly in SNU-251 for 24 hr and in SNU-C4 for 48 hr. In both green and red mustard leaf, sinigrin was the most abundant glucosinolte and was determined as 4.71 and 3.06 ㎎/g dry wt., respectively, but glucoiberin only presented 0.14 ㎎/g dry wt. with minor amounts.

In the original paper, there were a number of errors in Figures 4 and 7. Here, we provide the right form of these figures. In Figure 4(a), p-JNK panels were the same in the HN4 and HN12 cells. In Figure 4(d), vertical, light streaks were included in the p-JNK panel of HN4 during the scanning of X-ray film. In Figure 7(c), vertical, light streaks were included in the NF-B p65 nuclear panel of HN4 during the scanning of X-ray film.