Jing Ru Weng

A Novel Single Nucleotide Polymorphism in XRCC4 Gene is Associated with Gastric Cancer Susceptibility in Taiwan

BackgroundThe DNA repair gene XRCC4, an important caretaker of the overall genome stability, is thought to play a major role in the human carcinogenesis. We investigate some novel and important polymorphic variants of XRCC4, at codon 247 (rs3734091), G-1394T (rs6869366), intron 3 (rs28360071), and intron 7 (rs28360317), of their associated with gastric cancer susceptibility.Materials and MethodsIn this hospital-based case-control study, the association of XRCC4 polymorphisms with gastric cancer risk in a Taiwanese population was investigated. In total, 121 patients with gastric cancer and 121 age-matched healthy controls recruited were genotyped investigating these polymorphisms’ association with gastric cancer susceptibility.ResultsWe found a significant difference in the frequency of the XRCC4 G-1394T genotype, but not others, between the gastric cancer and control groups. Those who had G/T or G/G at XRCC4 G-1394T showed a 3.79-fold (95% confidence interval = 1.47–9.82) increased risk of gastric cancer compared to those with T/T. As for XRCC4 codon 247, intron 3, or intron 7, there was no difference in distribution between the gastric cancer and control groups.ConclusionsOur findings suggest that the G allele of the XRCC4 G-1394T may contribute to gastric carcinogenesis and may be useful for gastric cancer early detection and prevention.

A Potent Indole-3-Carbinol–Derived Antitumor Agent with Pleiotropic Effects on Multiple Signaling Pathways in Prostate Cancer Cells

Indole-3-carbinol has emerged as a promising chemopreventive agent due to its in vivo efficacy in various animal models. However, indole-3-carbinol exhibits weak antiproliferative potency and is unstable in acidic milieu. Thus, this study was aimed at exploiting indole-3-carbinol to develop potent antitumor agents with improved chemical stability. This effort culminated in OSU-A9 {[1-(4-chloro-3-nitrobenzenesulfonyl)-1H-indol-3-yl]-methanol}, which is resistant to acid-catalyzed condensation, and exhibits 100-fold higher apoptosis-inducing activity than the parent compound. Relative to indole-3-carbinol, OSU-A9 displays a striking qualitative similarity in its effects on the phosphorylation or expression of multiple signaling targets, including Akt, mitogen-activated protein kinases, Bcl-2 family members, survivin, nuclear factor-kappaB, cyclin D1, p21, and p27. The ability of OSU-A9 to concurrently modulate this broad range of signaling targets underscores its in vitro and in vivo efficacy in prostate cancer cells. Nevertheless, despite this complex mode of mechanism, normal prostate epithelial cells were less susceptible to the antiproliferative effect of OSU-A9 than PC-3 and LNCaP prostate cancer cells. Treatment of athymic nude mice bearing established s.c. PC-3 xenograft tumors with OSU-A9 at 10 and 25 mg/kg i.p. for 42 days resulted in a 65% and 85%, respectively, suppression of tumor growth. Western blot analysis of representative biomarkers in tumor lysates revealed significant reductions in the intratumoral levels of phosphorylated (p-) Akt, Bcl-xL, and RelA, accompanied by robust increases in p-p38 levels. In conclusion, the ability of OSU-A9 to target multiple aspects of cancer cell survival with high potency suggests its clinical value in prostate cancer therapy.

OSU-A9 inhibits angiogenesis in human umbilical vein endothelial cells via disrupting Akt–NF-κB and MAPK signaling pathways

Since the introduction of angiogenesis as a useful target for cancer therapy, few agents have been approved for clinical use due to the rapid development of resistance. This problem can be minimized by simultaneous targeting of multiple angiogenesis signaling pathways, a potential strategy in cancer management known as polypharmacology. The current study aimed at exploring the anti-angiogenic activity of OSU-A9, an indole-3-carbinol-derived pleotropic agent that targets mainly Akt-nuclear factor-kappa B (NF-κB) signaling which regulates many key players of angiogenesis such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Human umbilical vein endothelial cells (HUVECs) were used to study the in vitro anti-angiogenic effect of OSU-A9 on several key steps of angiogenesis. Results showed that OSU-A9 effectively inhibited cell proliferation and induced apoptosis and cell cycle arrest in HUVECs. Besides, OSU-A9 inhibited angiogenesis as evidenced by abrogation of migration/invasion and Matrigel tube formation in HUVECs and attenuation of the in vivo neovascularization in the chicken chorioallantoic membrane assay. Mechanistically, Western blot, RT-PCR and ELISA analyses showed the ability of OSU-A9 to inhibit MMP-2 production and VEGF expression induced by hypoxia or phorbol-12-myristyl-13-acetate. Furthermore, dual inhibition of Akt-NF-κB and mitogen-activated protein kinase (MAPK) signaling, the key regulators of angiogenesis, was observed. Together, the current study highlights evidences for the promising anti-angiogenic activity of OSU-A9, at least in part through the inhibition of Akt-NF-κB and MAPK signaling and their consequent inhibition of VEGF and MMP-2. These findings support OSU-A9s clinical promise as a component of anticancer therapy.

Cucurbitane triterpenoid from momordica charantia induces apoptosis and autophagy in breast cancer cells, in part, through peroxisome proliferator-activated receptor γ activation

Although the antitumor activity of the crude extract of wild bitter gourd (Momordica charantia L.) has been reported, its bioactive constituents and the underlying mechanism remain undefined. Here, we report that 3β,7β-dihydroxy-25-methoxycucurbita-5,23-diene-19-al (DMC), a cucurbitane-type triterpene isolated from wild bitter gourd, induced apoptotic death in breast cancer cells through peroxisome proliferator-activated receptor (PPAR) γ activation. Luciferase reporter assays indicated the ability of DMC to activate PPARγ, and pharmacological inhibition of PPARγ protected cells from DMCs antiproliferative effect. Western blot analysis indicated that DMC suppressed the expression of many PPARγ-targeted signaling effectors, including cyclin D1, CDK6, Bcl-2, XIAP, cyclooxygenase-2, NF-κB, and estrogen receptor α, and induced endoplasmic reticulum stress, as manifested by the induction of GADD153 and GRP78 expression. Moreover, DMC inhibited mTOR-p70S6K signaling through Akt downregulation and AMPK activation. The ability of DMC to activate AMPK in liver kinase (LK) B1-deficient MDA-MB-231 cells suggests that this activation was independent of LKB1-regulated cellular metabolic status. However, DMC induced a cytoprotective autophagy presumably through mTOR inhibition, which could be overcome by the cotreatment with the autophagy inhibitor chloroquine. Together, the ability of DMC to modulate multiple PPARγ-targeted signaling pathways provides a mechanistic basis to account for the antitumor activity of wild bitter gourd.

Antitumor effects of (S)-HDAC42, a phenylbutyrate-derived histone deacetylase inhibitor, in multiple myeloma cells

PurposeEpigenetic agents are among the newly targeted therapeutic strategies being studied with intense interest for patients with multiple myeloma. Here, we demonstrate the antitumor activity of a phenylbutyrate-based histone deacetylase (HDAC) inhibitor, (S)-HDAC42, and identify its possible targets in myeloma cells.MethodsThe antiproliferative effect of (S)-HDAC42 was compared with suberoylanilide hydroxamic acid (SAHA) in three myeloma cell lines, IM-9, RPMI-8226, and U266. Flow cytometry and terminal transferase dUTP nick-end labeling (TUNEL) assay were used to demonstrate the induction of apoptosis by (S)-HDAC42. Moreover, the proposed mechanisms of action, such as modulation of Akt, NF-κB pathway, and cell cycle–related proteins, were investigated by western blotting.Results(S)-HDAC42 exhibited four- to sevenfold higher potency relative to SAHA in suppressing myeloma cell viabilities. The apoptotic effect induced by (S)-HDAC42 was through both intrinsic and extrinsic pathways, as evidenced by increased cleavage of caspase-3, caspase-8, and caspase-9 and release of cytochrome c from mitochondria. In addition to HDAC inhibition, (S)-HDAC42 also disturbed signaling pathways governing cell survival, including downregulating Akt phosphorylation and NF-κB signaling. The modulation of cell cycle–related proteins by (S)-HDAC42 suggested its inhibitory effect on cell cycle propagation.ConclusionThese data suggest the translational value of (S)-HDAC42 in developing new therapeutic strategies for myeloma, which warrants further investigations.

G15, a GPR30 antagonist, induces apoptosis and autophagy in human oral squamous carcinoma cells.

As GPR30 has been implicated in mediating cancer cell proliferation, this study aimed to examine the antitumor effect of the GPR30 antagonist G15 in human oral squamous cell carcinoma (OSCC). G15 induced dose-dependent cytotoxicity, apoptosis and G2/M cell cycle arrest in a panel of OSCC cells. The results showed that G15 could inhibit the growth of the oral cancer cells with IC50 value 11.2 μM for SCC4, 15.6 μM for SCC9, and 7.8 μM for HSC-3, respectively. Flow cytometric analysis and Comet assay indicated that G15 suppressed the viability of SCC4 and HSC-3 cells by inducing apoptosis and G2/M arrest. In addition, G15 down regulated the expression of Akt, cell cycle-related proteins, and mitogen-activated protein kinases, but increased the levels of LC3B-II and the accumulation of autophagosomes. Inhibition of autophagy by chloroquine does not affect the G15-induced apoptosis in SCC4 cells. Mechanistic evidence indicated that the antiproliferative effect was mediated through the downregulation of cdc2, cdc25c and NF-κB expression. Taken together, our findings suggest the potential of G15 in treating OSCC.

A triterpenoid from wild bitter gourd inhibits breast cancer cells

The antitumor activity of 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al (TCD), a triterpenoid isolated from wild bitter gourd, in breast cancer cells was investigated. TCD suppressed the proliferation of MCF-7 and MDA-MB-231 breast cancer cells with IC50 values at 72 h of 19 and 23 μM, respectively, via a PPARγ−independent manner. TCD induced cell apoptosis accompanied with pleiotrophic biological modulations including down-regulation of Akt-NF-κB signaling, up-regulation of p38 mitogen-activated protein kinase and p53, increased reactive oxygen species generation, inhibition of histone deacetylases protein expression, and cytoprotective autophagy. Together, these findings provided the translational value of TCD and wild bitter gourd as an antitumor agent for patients with breast cancer.

OSU-A9, an indole-3-carbinol derivative, induces cytotoxicity in acute myeloid leukemia through reactive oxygen species-mediated apoptosis.

Indole-3-carbinol (I3C) is a broadly targeted phytochemical shown to prevent carcinogenesis in animal studies and to suppress the proliferation of cancer cells of human breast, colon, prostate, and endometrium. Here we demonstrate that OSU-A9, an I3C derivative with improved anticancer potency, induces cytotoxicity in acute myeloid leukemia (AML) cell lines (HL-60 and THP-1) and primary leukemia cells from AML patients in a dose-responsive manner. Normal human bone marrow cells were less sensitive to OSU-A9 than leukemia cells. OSU-A9 induces caspase activation, PARP cleavage, and autophagy but not autophagic cell death. Interestingly, pretreatment of AML cell lines and primary AML cells with N-acetylcysteine or glutathione rescues them from apoptosis (and concomitant PARP cleavage) and Akt hypophosphorylation, implicating a key role of reactive oxygen species (ROS) in OSU-A9-related cytotoxicity. Importantly, the anticancer utility of OSU-A9 is extended in vivo as it, administered intraperitoneally, suppresses the growth of THP-1 xenograft tumors in athymic nude mice without obvious toxicity. This study shows that ROS-mediated apoptosis contributes to the anticancer activity of OSU-A9 in AML cell lines and primary AML cells, and thus should be considered in the future assessment of its translational value in AML therapy.

A novel indole-3-carbinol derivative inhibits the growth of human oral squamous cell carcinoma in vitro.

Indole-3-carbinol (I3C), a naturally occurring phytochemical found in cruciferous vegetables, has received much attention due to its translational potential in cancer prevention and therapy. In this study, we investigated the antitumor effects of OSU-A9, a structurally optimized I3C derivative, in a panel of oral squamous cell carcinoma cell lines, SCC4, SCC15, and SCC2095. The antiproliferative effect of OSU-A9 was approximately two-orders-of-magnitude higher than that of I3C. Importantly, normal human oral keratinocytes were less sensitive to OSU-A9 than oral cancer cells. This antiproliferative effect of OSU-A9 was attributable to the induction of mitochondrial-dependent apoptosis as evidenced by sub-G1 accumulation of cells, poly ADP-ribose polymerase cleavage, and cytochrome c release from the mitochondria. OSU-A9 down regulates Akt and NF-κB signaling pathways, leading to changes in many downstream effectors involved in regulating cell cycle and apoptosis. Moreover, the observed down regulation of IKKα and IKKβ expression by OSU-A9 is not reported for I3C. OSU-A9 also induces both the production of reactive oxygen species and the endoplasmic reticulum stress. Taken together, these results suggest the translational value of OSU-A9 in oral squamous cell cancer therapy in the future.

Anti-inflammatory effects of Calophyllum inophyllum L. in RAW264.7 cells

Calophyllum inophyllum L. has been used as folk medicine in the treatment of ocular burn and it has demonstrated potential to be an anti-inflammatory agent. The aim of this study was to explore the anti-inflammatory activities of an acetone extract of C. inophyllum L. leaves (CIL). The CIL extract was tested on lipopolysaccharide (LPS)-induced RAW 264.7 cells to evaluate the effect of CIL extract on the expression of nitric oxide (NO) and inducible nitric oxide synthase (iNOS). Results showed that the CIL extract markedly suppressed the LPS-induced production of nitric oxide, as well as the expression of iNOS, cyclooxygenase (COX)-2 and nuclear factor-kappaB (NF-κB) in a dose-dependent manner. LPS-induced microRNA (miR)-146a expression was inhibited by CIL extract, while miR-155 and miR-424 expression was not affected as demonstrated using quantitative RT-PCR analysis. Taken together, these observations show that CIL extract has anti-inflammatory effect, which extends the potential application for prevention of inflammatory diseases, and its mechanism may be partially associated with blocking COX-2 and iNOS of RAW 264.7 cells.