Somatic alterations in mitochondrial DNA produce changes in cell growth and metabolism supporting a tumorigenic phenotype

There have been many reports of mitochondrial DNA (mtDNA) mutations associated with human malignancies. We have observed allelic instability in UV-induced cutaneous tumors at the mt-Tr locus encoding the mitochondrial tRNA for arginine. We examined the effects of somatic alterations at this locus by modeling the change in a uniform nuclear background by generating cybrids harboring allelic variation at mt-Tr. We utilized the naturally occurring mtDNA variation at mt-Tr within the BALB/cJ (BALB) and C57BL/6J (B6) strains of Mus musculus to transfer their mitochondria into a mouse ρ(0) cell line that lacked its own mtDNA. The BALB haplotype containing the mt-Tr 9821insA allele produced significant changes in cellular respiration (resulting in lowered ATP production), but increased rates of cellular proliferation in cybrid cells. Furthermore, the mtDNA genotype associated with UV-induced tumors endowed the cybrid cells with a phenotype of resistance to UV-induced apoptosis and enhanced migration and invasion capabilities. These studies support a role for mtDNA changes in cancer.     

坏死细胞释放IL-1β对血管平滑肌细胞侵袭和迁移的影响及机制研究

目的研究坏死血管平滑肌细胞释放IL-1β对周围正常细胞侵袭和迁移的影响,并探讨其可能的机制。方法无血清低糖低氧条件下培养细胞,建立细胞坏死模型,收集坏死细胞培养上清液,用于干预正常血管平滑肌细胞。实验设坏死上清组（NCS）、IL-1β组、NCS＋IL-1RA组和对照组（Control）。Tran-swell小室实验和细胞划痕实验检测各组细胞侵袭和迁徙能力,RT-PCR和Western印迹检测各组MMP-2和MMP-9的表达,Western印迹检测各组NF-κB的激活情况。结果NCS组和IL-1β组细胞侵袭和迁移能力均显著高于对照组（P〈0．05）,NCS＋IL-1RA组细胞侵袭和迁移能力显著低于NCS组和IL-1组（P〈0．05）;对照组和NCS＋IL．1RA组NF-κB、MMP-2和MMP-9均显著低于NCS组和IL-1β组（P〈0．05）,IκB显著高于NCS组和IL-1β组（P〈0．05）。使用NF-κB特异性抑制剂处理后,NCS组和IL-1β组细胞侵袭和迁移能力显著性降低（P〈0．01）;MMP-2和MMP-9的表达也显著性减少（P〈0．01）。结论坏死血管平滑肌细胞能够上调MMP-2和MMP-9的表达,促进正常细胞的侵袭和迁移,且这种促进作用与IL-1β的大量释放诱导NF-κB的活化有关。     

Somatic alterations in mitochondrial DNA produce changes in cell growth and metabolism supporting a tumorigenic phenotype

There have been many reports of mitochondrial DNA (mtDNA) mutations associated with human malignancies. We have observed allelic instability in UV-induced cutaneous tumors at the mt-Tr locus encoding the mitochondrial tRNA for arginine. We examined the effects of somatic alterations at this locus by modeling the change in a uniform nuclear background by generating cybrids harboring allelic variation at mt-Tr. We utilized the naturally occurring mtDNA variation at mt-Tr within the BALB/cJ (BALB) and C57BL/6J (B6) strains of Mus musculus to transfer their mitochondria into a mouse ρ⁰ cell line that lacked its own mtDNA. The BALB haplotype containing the mt-Tr 9821insA allele produced significant changes in cellular respiration (resulting in lowered ATP production), but increased rates of cellular proliferation in cybrid cells. Furthermore, the mtDNA genotype associated with UV-induced tumors endowed the cybrid cells with a phenotype of resistance to UV-induced apoptosis and enhanced migration and invasion capabilities. These studies support a role for mtDNA changes in cancer.     

Ectopic expression of CC chemokine receptor 7 promotes prostate cancer cells metastasis via Notch1 signaling

There currently exists no satisfactory treatment for patients with prostate cancer with local evolution and distant metastasis. Previous studies have confirmed the importance of CC chemokine receptor 7 (CCR7) in the invasion and metastasis of prostate cancer. And increasing evidence prove that Notch1 can play diametrically opposite roles in the development and progression of different tumors. To demonstrate the correlation between CCR7 and Notch1, PC-3 cells were transfected with pcDNA3.1-CCR7 or CCR7 si-RNA, respectively. Then Western blot analysis was used to detect the expressions of Notch1, ERK, P38, JNK, NF-κB, MMP-9, and epithelial-mesenchymal transition (EMT)-related proteins. Moreover, matrigel invasion assays were performed to assess the migratory and invasive activities of PC-3 cells. PcDNA3.1-CCR7 increased the expression of Notch1, phospho-MAPK, phospho-P65, MMP-9, N-cadherin, and Snail in PC-3 cells, but decreased the expression of E-cadherin. PcDNA3.1-CCR7 also promoted the migration and invasion of PC-3 cells. However, CCR7 si-RNA reversed the effect of pcDNA3.1-CCR7 in PC-3 cells. And MAPK and NF-κB pathway inhibitors were used to testify that activation of Notch1 induces EMT through MAPK and NF-κB pathway. All these results indicate that upregulation of Notch1 by CCR7 can accelerate the evolution of EMT and develop the invasion and metastasis in prostate cancer cells by activating MAPK and NF-κB signaling pathways in prostate cancer cells, which provides a new molecular evidence for targeted therapy in metastatic prostate cancer.     

Ras activation mediates WISP-1-induced increases in cell motility and matrix metalloproteinase expression in human osteosarcoma

WISP-1 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matrix cellular proteins. Osteosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. However, the effect of WISP-1 on migration activity in human osteosarcoma cells is mostly unknown. In this study, we first found that the expression of WISP-1 in osteosarcoma patients was significantly higher than that in normal bone and corrected with tumor stage. Exogenous treatment of osteosarcoma cells with WISP-1 promoted cell motility and matrix metalloproteinase (MMP)-2 and MMP-9 expression. In addition, the Ras and Raf-1 inhibitor or siRNA abolished WISP-1-induced cell migration and MMP expression. On the other hand, activation of the Ras, Raf-1, MEK, ERK, and NF-κB signaling pathway after WISP-1 treatment was demonstrated, and WISP-1-induced expression of MMPs and migration activity were inhibited by the specific inhibitor, and mutant of MEK, ERK, and NF-κB cascades. Taken together, our results indicated that WISP-1 enhances the migration of osteosarcoma cells by increasing MMP-2 and MMP-9 expression through the integrin receptor, Ras, Raf-1, MEK, ERK, and NF-κB signal transduction pathway.     

Discovery of lesser known flavones as inhibitors of NF-κB signaling in MDA-MB-231 breast cancer cells—A SAR study

Seventeen flavonoids with different substitutions were evaluated for inhibition of nuclear factor-κB (NF-κB) signaling in the invasive breast cancer cell line MDA-MB-231. They were screened using an engineered MDA-MB-231 cell line reporting NF-κB activation. The modulation of expression of two NF-κB regulated genes involved in tumorigenesis, matrix metalloproteinase-9 (MMP-9), and cyclooxygenase-2 (COX-2) were also analyzed in these cells. Among the compounds tested, all except gossypetin and quercetagetin inhibited the activation of NF-κB, and the expression of MMP-9 and COX-2 to different degree. Methylated flavone, chrysoeriol (luteolin-3′-methylether), was found to be the most potent inhibitor of MMP-9 and COX-2 expressions. The effect of chrysoeriol on cell proliferation, cell cycle, apoptosis and metastasis was analyzed by established methods. Chrysoeriol caused cell cycle arrest at G2/M and inhibited migration and invasion of MDA-MB-231 cells. The structure–activity relations amongst the flavonoids as NF-κB signaling inhibitors was studied. The study indicates differences between the actions of various flavonoids on NF-κB activation and on the biological activities of breast cancer cells. Flavones in general, were more active than the corresponding flavonols.     

海参多糖抑制人肾癌细胞A498的生长转移作用机制

肾细胞癌(RCC)是最常见的恶性癌之一,癌症转移是目前导致肾癌患者死亡的主要原因之一。MMP-9被发现在许多具有侵袭性和转移能力的人类癌症中过表达,其表达和分泌受到NF-κB调控;VEGF在维持原发性癌和转移瘤生长所需的血管生成中发挥重要作用,其表达也受到活化的NF-κB调节。海参的多种活性物质在抗氧化、抗菌和抗癌方面都有出色的作用,而抗癌的主要机制则包括诱导癌细胞凋亡、抑制癌细胞生长、减少癌细胞转移等。本研究通过利用不同浓度的海参多糖处理人肾癌细胞A498,采用MTT细胞增殖实验、粘附实验、迁移实验和小室侵袭实验,研究了海参多糖对A498细胞的生长转移的影响;采用蛋白印记法检测了海参多糖对A498细胞内MMP-9、NF-κBp65和VEGF表达水平的影响。结果表明,海参多糖能够显著抑制A498细胞的增殖活力、粘附能力、迁移能力和侵袭能力,并且全都表现出明显的剂量依赖性;中浓度(100μg/mL)和高浓度(200μg/mL)的海参多糖能够显著下调A498细胞内MMP-9、NF-κBp65和VEGF的表达。这些结果说明海参多糖能有效抑制人肾癌细胞A498的生长、转移和侵袭,可能的机制是通过抑制NF-κB信号通路下调MMP-9和VEGF的表达,从而发挥抗癌细胞转移的作用。     

Antitumor effects of the flavone chalcone: inhibition of invasion and migration through the FAK/JNK signaling pathway in human gastric adenocarcinoma AGS cells

Chalcones (benzylideneacetophenone) are cancer-preventive food components found in a human diet rich in fruits and vegetables. In this study, we first report the chemopreventive effect of chalcone in human gastric adenocarcinoma cell lines: AGS. The results showed that chalcone could inhibit the abilities of the adhesion, invasion, and migration by cell–matrix adhesion assay, Boyden chamber invasion/migration assay, and wound-healing assay. Molecular data showed that the effect of chalcone in AGS cells might be mediated via sustained inactivation of the phosphorylation of focal adhesion kinase (FAK) and c-Jun N-terminal kinase 1 and 2 (JNK1/2) signal involved in the downregulation of the expressions of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Next, chalcone-treated AGS cells showed tremendous decrease in the phosphorylation and degradation of inhibitor of kappaBα (IκBα), the nuclear level of NF-κB, and the binding ability of NF-κB to NF-κB response element. Furthermore, treating FAK small interfering RNA (FAK siRNA) and specific inhibitor for JNK (SP600125) to AGS cells could reduce the phosphorylation of JNK1/2 and the activity of MMP-2 and MMP-9. Our results revealed that chalcone significantly inhibited the metastatic ability of AGS cells by reducing MMP-2 and MMP-9 expressions concomitantly with a marked reduction on cell invasion and migration through suppressing and JNK signaling pathways. We suggest that chalcone may offer the application in clinical medicine.     

Acacetin, a flavonoid, inhibits the invasion and migration of human prostate cancer DU145 cells via inactivation of the p38 MAPK signaling pathway

Acacetin (5,7-dihydroxy-4′-methoxyflavone), a flavonoid compound, has anti-peroxidative and anti-inflammatory effects. The effect of acacetin on antimetastasis in human prostate cancer DU-145 cells was investigated. First, the result demonstrated acacetin could exhibit an inhibitory effect on the abilities of the adhesion, invasion, and migration by cell–matrix adhesion assay, wound-healing assay, and Boyden chamber assay. Data also showed acacetin could inhibit the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) involved in the downregulation of the expressions of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator (u-PA) at both the protein and mRNA levels. Next, acacetin significantly decreased the nuclear levels of nuclear factor kappa B (NF-κB), c-Fos, and c-Jun. Also, the treatment with acacetin to DU145 cells also leads to a dose-dependent inhibition on the binding ability of NF-κB and activator protein-1 (AP-1). Furthermore, the treatment of inhibitors specific for p38 MAPK (SB203580) to DU145 cells could cause reduced expressions of MMP-2, MMP-9, and u-PA. These results showed acacetin could inhibit the invasion and migration abilities of DU145 cells by reducing MMP-2, MMP-9, and u-PA expressions through suppressing p38 MAPK signaling pathway and inhibiting NF-κB- or AP-1-binding activity. These findings proved acacetin might be offered further application as an antimetastatic agent.     

Suppression of 12-O-Tetradecanoylphorbol-13-Acetate-Induced MCF-7 Breast Adenocarcinoma Cells Invasion/Migration by α-Tomatine Through Activating PKCα/ERK/NF-κB-Dependent MMP-2/MMP-9 Expressions

α-Tomatine, isolated from Lycopersicon esculentum Linn., is a naturally occurring glycoalkaloids in immature green tomatoes. Some reports demonstrated that α-tomatine had various anti-carcinogenic properties. First, the result demonstrated α-tomatine could inhibit TPA-induced the abilities of the adhesion, morphology/actin cytoskeleton arrangement, invasion, and migration by cell–matrix adhesion assay, immunofluorescence stain assay, Boyden chamber invasion assay, and wound-healing assay. Data also showed α-tomatine could inhibit the activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and protein kinase C-α (PKCα) involved in the downregulation of the enzyme activities and messenger RNA levels of matrix metalloproteinase-2/9 (MMP-2/MMP-9) induced by TPA. Next, α-tomatine also strongly inhibited TPA-induced the activation of nuclear factor kappa B (NF-κB) and phospho-inhibitor of kappa Bα (phospho-IκBα). In addition, TPA-induced translocation of PKC-α from cytosol to membranes, and suppression of TPA elicited the expression of PKC-α by adding the PKC-α inhibitors, GF-109203X and Gö-6983. The treatment of specific inhibitor for ERK (U0126) to MCF-7 cells could inhibit TPA-induced MMP-2/MMP-9 and phospho-ERK along with an inhibition on cell invasion and migration. Application of α-tomatine to prevent the invasion/migration of MCF-7 cells through blocking PKCα/ERK/NF-κB activation is first demonstrated herein.     

棕榈酸促进肝癌细胞侵袭转移的分子机制

目的:探讨棕榈酸(Palmiticacid,PA)对人肝癌细胞系SMMC-7721侵袭转移能力的影响,并通过检测肝癌细胞系中CD147-MMPs信号通路在PA影响下的变化,初探PA影响肝癌细胞侵袭转移的分子机制。方法:PA(0、20、50、100μM)作用SMMC-7721细胞后(8、16、24h),MTT法检测细胞增殖,划痕及Transwell实验评价细胞迁移侵袭能力,Western-blot及real-time PCR检测CD147蛋白及其mRNA的水平,ELISA检测基质金属蛋白酶(MMP-2,MMP-9)的水平。结果:与对照组相比,PA作用SMMC-7721细胞后,细胞存活率无显著差异(P0.05);细胞迁移和侵袭能力显著增高(P0.05);CD147蛋白及其mRNA的表达显著增高(P0.05);培养上清中MMP-9的浓度显著增高(P0.05),MMP-2的水平则无变化。不同的梯度组之间相比较,细胞迁移和侵袭能力、CD147的表达水平(蛋白及其mRNA)以及培养上清中MMP-9的浓度均随PA作用时间和作用剂量的增大而产生更显著的增高。结论:PA通过活化CD147-MMPs信号通路促进SMMC-7721细胞的迁移侵袭。     

Extracellular matrix protein fibronectin induces matrix metalloproteinases in human prostate adenocarcinoma cells PC-3

Abstract

Studies on interaction of tumor cells with ECM components showed increased extracellular protease activity mediated by the family of matrix metalloproteinases (MMPs). Here we studied the effect of human prostate adenocarcinoma PC-3 cells–fibronectin (FN) interaction on MMPs and the underlying signaling pathways. Culturing of PC-3 cells on FN-coated surface upregulated MMP-9 and MMP-1. This response is abrogated by the blockade of α₅ integrin. siRNA and inhibitor studies indicate possible involvement of phosphatidyl-inositol-3-kinase (PI-3K), focal adhesion kinase (FAK) and nuclear factor-kappaB (NF-κB) in FN-induced upregulation of MMPs. FN treatment also enhanced phosphorylation of FAK, PI3K, protein kinase B (PKB or Akt), nuclear translocation of NF-κB, surface expression of CD-44, and cell migration. Our findings indicate that, binding of PC-3 cells to FN, possibly via α_5β1 integrin, induces signaling involving FAK, PI-3K, Akt, NF-κB followed by upregulation of MMP-9 and MMP-1. CD-44 may have role in modulating MMP-9 activity.