Metallothionein 3 Is a Hypoxia-Upregulated Oncogene Enhancing Cell Invasion and Tumorigenesis in Human Bladder Carcinoma Cells

Metallothioneins have been viewed as modulators in a number of biological regulations regarding cancerous development; however, the function of metallothionein 3 (MT3) in bladder cancer is unexplored. We determined the regulatory mechanisms and potential function of MT3 in bladder carcinoma cells. Real-Time Reverse Transcriptase-Polymerase Chain Reaction (RT-qPCR) assays revealed that TSGH-8301 cells expressed more MT3 levels than RT-4, HT1376, and T24 cells. Immunoblot and RT-qPCR assays showed that arsenic (AS2O3) treatments enhanced the gene expression of MT3. Hypoxia induced HIF-1α, HIF-2α, and MT3 expression; furthermore, HIF-2α-knockdown attenuated hypoxic activation on MT3 expression. Ectopic overexpression of MT3 increased cell proliferation, invasion, and tumorigenesis significantly in T24 and HT1376 cells in vitro and in vivo; however, MT3-knockdown in TSGH-8301 cells had the reverse effect. Moreover, knockdown of MT3 enhanced arsenic-induced apoptosis determined by the Annexin V-FITC apoptosis assay. MT3-overexpression downregulated the gene expressions of N-myc downstream regulated gene 1 (NDRG1), N-myc downstream regulated gene 2 (NDRG2), and the mammary serine protease inhibitor (MASPIN) in HT1376 and T24 cells, whereas MT3-knockdown in TSGH-8301 cells had the opposite effect. The experiments indicated that MT3 is an arsenic- and hypoxia-upregulated oncogene that promotes cell growth and invasion of bladder carcinoma cells via downregulation of NDRG1, NDRG2, and MASPIN expressions

Biological Mechanisms by Which Antiproliferative Actions of Resveratrol Are Minimized

Preclinical and clinical studies have offered evidence for protective effects of various polyphenol-rich foods against cardiovascular diseases, neurodegenerative diseases, and cancers. Resveratrol is among the most widely studied polyphenols. However, the preventive and treatment effectiveness of resveratrol in cancer remain controversial because of certain limitations in existing studies. For example, studies of the activity of resveratrol against cancer cell lines in vitro have often been conducted at concentrations in the low μM to mM range, whereas dietary resveratrol or resveratrol-containing wine rarely achieve nM concentrations in the clinic. While the mechanisms underlying the failure of resveratrol to inhibit cancer growth in the intact organism are not fully understood, the interference by thyroid hormones with the anticancer activity of resveratrol have been well documented in both in vitro and xenograft studies. Thus, endogenous thyroid hormones may explain the failure of anticancer actions of resveratrol in intact animals, or in the clinic. In this review, mechanisms involved in resveratrol-induced antiproliferation and effects of thyroid hormones on these mechanisms are discussed

Caffeic Acid Phenethyl Ester Induces N-myc Downstream Regulated Gene 1 to Inhibit Cell Proliferation and Invasion of Human Nasopharyngeal Cancer Cells

Caffeic acid phenethyl ester (CAPE), a bioactive component extracted from propolis, is widely studied due to its anti-cancer effect. Nasopharyngeal carcinoma (NPC) is distinct from other head and neck carcinomas and has a high risk of distant metastases. N-myc downstream regulated gene 1 (NDRG1) is demonstrated as a tumor suppressor gene in several cancers. Our result showed that CAPE treatment could repress NPC cell growth, through induction of S phase cell cycle arrest, and invasion. CAPE treatment stimulated NDRG1 expression in NPC cells. NDRG1 knockdown increased NPC cell proliferation and invasion and rendered NPC cells less responsive to CAPE growth-inhibiting effect, indicating CAPE repressed NPC cell growth partly through NDRG1indcution. CAPE treatment increased phosphorylation of ERK, JNK, and p38 in a dose- and time-dependent manner. Pre-treatments by inhibitors of ERK (PD0325901), JNK (SP600125), or p38 (SB201290), respectively, all could partly inhibit the CAPE effect on NDRG1 induction in NPC cells. Further, STAT3 activity was also repressed by CAPE in NPC cells. In summary, CAPE attenuates NPC cell proliferation and invasion by upregulating NDRG1 expression via MAPK pathway and by inhibiting phosphorylation of STAT3. Considering the poor prognosis of NPC patients with metastasis, CAPE could be a promising agent against NPC

Multiple Patterns of Regulation and Overexpression of a Ribonuclease-Like Pathogenesis-Related Protein Gene, <i>OsPR10a</i>, Conferring Disease Resistance in Rice and <i>Arabidopsis</i>

<div><p>An abundant 17 kDa RNase, encoded by <i>OsPR10a</i> (also known as PBZ1), was purified from P_i-starved rice suspension-cultured cells. Biochemical analysis showed that the range of optimal temperature for its RNase activity was 40–70°C and the optimum pH was 5.0. Disulfide bond formation and divalent metal ion Mg²⁺ were required for the RNase activity. The expression of <i>OsPR10a</i>::<i>GUS</i> in transgenic rice was induced upon phosphate (P_i) starvation, wounding, infection by the pathogen <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>), leaf senescence, anther, style, the style-ovary junction, germinating embryo and shoot. We also provide first evidence in whole-plant system, demonstrated that <i>OsPR10a</i>-overexpressing in rice and <i>Arabidopsis</i> conferred significant level of enhanced resistance to infection by the pathogen <i>Xoo</i> and <i>Xanthomona campestris</i> pv. <i>campestris</i> (<i>Xcc</i>), respectively. Transgenic rice and <i>Arabidopsis</i> overexpressing <i>OsPR10a</i> significantly increased the length of primary root under phosphate deficiency (-P_i) condition. These results showed that <i>OsPR10a</i> might play multiple roles in phosphate recycling in phosphate-starved cells and senescing leaves, and could improve resistance to pathogen infection and/or against chewing insect pests. It is possible that P_i acquisition or homeostasis is associated with plant disease resistance. Our findings suggest that gene regulation of <i>OsPR10a</i> could act as a good model system to unravel the mechanisms behind the correlation between P_i starvation and plant-pathogen interactions, and also provides a potential application in crops disease resistance.</p></div

Phenotypes of WT and the <i>OsPR10a</i>-overexpressing transgenic seedlings under +P_i and –P_i conditions.

<p>Rice seeds were imbibed in distilled water for 3 days, germinating embryos were isolated and placed onto the vertical plates containing solid half-strength of MS medium supplemented with or without P_i. (A) and (B) Isolated embryos incubated either in +P_i medium (A) or–P_i medium (B) for another 6 days were photographed. Bars = 1 cm. (C) and (E) Quantitative analyses of shoot lengths (C) and primary roots (E) of seedlings cultured in +P_i medium. (D) and (F) Quantitative analyses of shoot lengths (D) and primary roots (F) of seedlings cultured in -P_i medium. Groups that do not share the same letter are significantly different estimated by ANOVA (P <0.05). Data are shown as means ±SD (n = 10).</p

Phosphate starvation induced <i>OsPR10a</i> gene expression in rice suspension-cultured cells.

<p>Rice suspension cells were cultured in MS medium for 3 days and transferred to MS medium supplemented with (+P_i) or without (-P_i) phosphate. Total RNA was isolated from cells and subjected to northern blot analysis using the <i>OsPR10a</i> coding region as a probe. The rRNA served as a total RNA loading control.</p

Histochemical staining for β-glucuronidase (GUS) activity in suspension-cultured cells, leaves, flowers, developing and germinating seeds of transgenic plants.

<p>(A) Schematic diagram of the <i>OsPR10a</i>::<i>GUS</i> expression construct. (B) GUS staining in rice suspension-cultured cells under phosphate starvation or following <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>) inoculation. (C) GUS expression patterns in young leaf (YL), mature leaf (ML) and senescent leaf (SL). (D) GUS staining in leaves with no treatment (control), wounding (Wound) or after spraying with <i>Xoo</i>. (E) GUS staining in flowers and developing seeds. BF: before flowering. (F) GUS staining in germinating seeds.</p

Agarose gel electrophoresis of enzymatic hydrolysates of yeast tRNA by the purified 17 kDa protein.

<p>A total of 0.5 μg of purified 17 kDa protein was mixed with or without 1.0 μg of rice genomic DNA (DNA) or 5.0 μg of yeast t-RNA (tRNA). The mixtures were incubated for the indicated times followed by 1.5% agarose gel electrophoresis.</p

RNase activities in rice suspension-cultured cells.

<p>(A) Rice cells were suspension-cultured in MS complete medium (containing 3% sucrose and 10 μM 2,4-D) for 3 days then transferred to MS complete medium with (■) or without (●) sucrose, or deficient in either phosphate (♦) or nitrogen (▲), and cells were collected at the time points indicated on the x-axis. Error bars indicate standard errors for the measurements from at least three individual experiments. (B) Rice suspension cells were grown for 3 days in MS medium with (+P_i) or without (-P_i) phosphate. Total protein was extracted from cultured cells and 40 μg of total cellular protein were applied to an in-gel RNase activity assay.</p