Inhibits Tumor Invasion Research Articles

Phenethyl isothiocyanate (PEITC) suppresses prostate cancer cell invasion epigenetically through regulating microRNA-194.

Tumor metastasis greatly contributes to the mortality of prostate cancer. The glucosinolate-derived phenethyl isothiocyanate (PEITC) has been widely documented to reduce the risk of prostate cancer by modulating multiple biologically relevant processes. Emerging evidence suggests that PEITC may exert its anti-cancer effects through epigenetic mechanisms including microRNAs. Altered levels of miRNA have been linked to tumor malignancy due to their capacity to regulate functional gene expression in carcinogenesis. Here, we assessed the effects of PEITC on miRNA expression which is related to PCa cell invasiveness. Utilizing oligonucleotide microarray first identified the most affected miRNAs in LNCaP cells after PEITC treatment. Several top altered miRNAs were further validated using quantitative PCR. Interestingly, overexpression of miR-194 suppressed PC3 cell invasion in matrigel-coated Transwell chambers. Bone morphogenetic protein 1 (BMP1) was shown to be a direct target of miR-194. Downregulation of BMP1 by miR-194 or PEITC led to decreased expression of key oncogenic matrix metalloproteinases, MMP2 and MMP9. This in turn resulted in the suppression of tumor invasion. Our results indicate that miR-194 downregulates the expression of oncogenic MMP2 and MMP9 by targeting BMP1, which suggests a potential new mechanistic target by which PEITC suppresses prostate cancer cell invasiveness.

MiR-136 suppresses tumor invasion and metastasis by targeting RASAL2 in triple-negative breast cancer.

MicroRNAs play an important role in the regulation of cancer migration, invasion and metastasis. Patients with triple-negative breast cancer (TNBC) have a high incidence of early relapse and metastasis; however, the molecular basis for metastasis and recurrence in these individuals remains largely unknown. Herein, we demonstrate that miR-136 is an anti-invasive microRNA in TNBC and suppresses mesenchymal invasion and metastasis. Our results demonstrated that miR-136 was downregulated in TNBC and negative correlated with the WHO grades. However, RASAL2 was identified as a functional target of miR-136, and was overexpressed in TNBC and correlates with pathological grades. Moreover, overexpression of RASAL2 in a breast cancer cell line rescued miR-136-mediated cell migration and invasion. In conclusion, these results indicate that the miR-136/RASAL2/MET axis act as a suppressor of TNBC metastasis.

H-prune affects anaplastic thyroid cancer invasion and metastasis.

Anaplastic thyroid cancer is one of the most aggressive human malignancies and is resistant to multimodal treatments. The expression of h-prune, the human homologue of Drosophila prune, has been reported to be correlated with progression and aggressiveness in various cancers including breast, colorectal and pancreatic cancers. We examined the role of h-prune in anaplastic thyroid cancer cell migration, invasion and metastasis. Immunohistochemical analysis of h-prune was performed with 15 surgically resected specimens of anaplastic thyroid cancers. To investigate cell motility, Boyden chamber, wound healing and matrigel invasion assays were performed using cells from anaplastic thyroid cancer cell lines. A murine orthotopic thyroid cancer model was used to investigate metastatic ability. In the immunohistochemical analysis, only weak focal or no staining of h-prune was observed in non-tumor tissue. In contrast, diffuse staining of h-prune was observed in anaplastic thyroid cancer and lymph node metastasis samples. Both inhibition of h-prune phosphodiesterase activity with dipyridamole and small interfering RNA for h-prune suppressed 8505C and KTC-3 cell motility. In addition, treatment with dipyridamole and decreased expression of h-prune suppressed tumor invasion and pulmonary metastasis in a NOD/Shi-scid, IL-2Rγnull (NOG) mouse orthotopic thyroid cancer model. In conclusion, h-prune is frequently expressed in anaplastic thyroid cancer cells and lymph nodes metastasis, and promotes migration and invasion of anaplastic thyroid cancer cells and metastasis in an anaplastic thyroid cancer model. Thus, h-prune shows promise as a targeting candidate against anaplastic thyroid cancer.

Superoxide- and no-dependent mechaniSmS of antitumor and antimetaStatic effect of L-arginine hydrochLoride and coenzyme Q10

To study the redox-dependent mechanism of antiradical, antitumor and antimetastatic action of L-arginine hydrochloride (L-Arg) and coenzyme Q10 (CoQ10) in vivo. The study was performed on С(57)Вl mice with transplanted Lewis lung carcinoma treated by intraperitoneal injections of L-Arg at low or high doses (60 and 360 mg/kg body weight), CoQ10 (0.2 and 1.2 mg/kg body weight) or their combinations. Electron paramagnetic resonance was applied for analysis of mitochondrial electron transport chain, СoQ10 levels, free iron (FI), the level of NO, and the rate of superoxide radical generation. The activity of matrix metalloproteinase (MMP)-2 and -9 in tumor tissue was determined by zymography method in polyacrylamide gel. Administration of L-Arg at high doses caused an inhibition of tumor growth by 48 ± 8.0%, increase of superoxide radical generation rate and NO levels to a value of 1.23 ± 0.14 and 2.26 ± 0.31 nm/g tissue · min, and decreased activity of MMP-2 and -9 (3.55 ± 0.8 and 4.8 ± 1.0 r.u., respectively). Treatment with L-Arg at low doses stimulated tumor growth and increased the levels of MMP-2 and -9 activities (8.44 ± 2.7 and 9.8 ± 3.1 r.u., respectively). Administration of СoQ10 at high doses significantly decreased superoxide radical generation rate to the values of 0.44 ± 0.09 nm/g tissue · min, levels of free iron and NO, and caused tumor growth inhibition by 54 ± 11.3%. The combined use of L-Arg and СoQ10 at high doses caused tumor growth inhibition by 51 ± 7.4% compared to Lewis lung carcinoma-bearing untreated animals (p<0.05). Administration of L-Arg and СoQ10 caused the dose-dependent effect on the rate of generation of superoxide radicals, level of ubisemyquinone, complexes NOFeS-proteins, levels of FI and NO. L-Arg at low doses positively modulated MMP-9 activity that promoted tumor progression. Upon combined use of L-Arg and СoQ10, superoxide radicals and NO form the redox state that causes decrease of MMP-2, -9 activities with consequent inhibition of tumor invasion and metastasis.

N-Myc-interacting protein (NMI) negatively regulates epithelial-mesenchymal transition by inhibiting the acetylation of NF-κB/p65

The epithelial-mesenchymal transition (EMT) plays an essential role in embryonic development, wound healing, tissue regeneration, organ fibrosis, and tumor progression. However, the mechanisms underlying this process are poorly understood. Many signaling pathways, including the NF-κB signaling pathway, trigger EMT during development and differentiation. In the present study, we report that N-Myc interactor (NMI) inhibits EMT progression by suppressing transcriptional activities of NF-κB in human gastric cancer cells. We show that the expression of NMI is significantly reduced in invasive gastric cancer cells and gastric cancer tissues. Overexpression of NMI inhibited cell migration and invasion, and this inhibition was enhanced after TNF-α stimulation. Tumorigenicity assay in nude mice support the notion that NMI inhibits EMT in cancer cells. Mechanistically, NMI promotes the interaction between NF-κB/p65 and histone deacetylases (HDACs) and inhibits the acetylation and transcriptional activity of p65. The expression of p65 rescues NMI-mediated inhibition of EMT and the inhibition of the acetylation of p65 mediated by NMI is HDACs-dependent. Taken together, these findings suggest that NMI can suppress tumor invasion and metastasis by inhibiting NF-κB pathways, providing an alternative mechanism for EMT inhibition in stomach neoplasm.

MicroRNA-379-5p inhibits tumor invasion and metastasis by targeting FAK/AKT signaling in hepatocellular carcinoma

Some microRNAs (miRNAs) have been implicated in hepatocellular carcinoma (HCC) development and progression. However, the roles and mechanisms of several miRNAs in HCC remain poorly understood. Here, we report that miR-379-5p, which is down-regulated in HCC tissues and cell lines, is associated with advanced TNM stage and metastasis in HCC. The ectopic overexpression of miR-379-5p inhibited HCC cell migration, invasion, epithelial-to-mesenchymal transition (EMT) and metastasis both in vitro and in vivo. Conversely, miR-379 knockdown increased migration, invasion and EMT in HCC cells. Moreover, miR-379-5p exerted this function by directly targeting focal adhesion kinase (FAK) 3′-UTR and repressing FAK expression, thus leading to suppression of AKT signaling. Furthermore, the tumor suppressive effects of miR-379-5p in HCC cells were reversed by activating AKT signaling or restoring FAK expression. In clinical samples of HCC, miR-379-5p negatively correlated with FAK, which was up-regulated in HCC. Taken together, our findings highlight the important role of miR-379-5p in regulating the EMT and metastasis of HCC by targeting FAK/AKT signaling, suggesting that miR-379-5p may represent a novel potential therapeutic target and prognostic marker for HCC.

α-Pinene inhibits tumor invasion through downregulation of nuclear factor (NF)-κB-regulated matrix metalloproteinase-9 gene expression in MDA-MB-231 human breast cancer cells

2,6,6-Trimethylbicyclo[3.1.1]hept-2-ene (α-Pinene) is an organic compound of the terpene class found in the essential oil of many plants. In this study, the inhibitory effect of α-pinene on tumor invasion in highly metastatic MDA-MB-231 human breast cancer cells was evaluated. α-Pinene inhibited tumor necrosis factor (TNF)-α-induced invasiveness of MDA-MB-231 cells as revealed by three-dimensional spheroid invasion assay. Further analysis showed that α-pinene reduced TNFα-induced matrix metalloproteinase-9 gene promoter activation and mRNA expression in a dose-dependent manner. In addition, α-pinene treatment attenuated TNFα-induced nuclear factor κB (NF-κB) activation and NF-κB-dependent transcriptional activity. These results suggest that α-pinene has a significant effect on the inhibition of tumor invasion and may potentially be developed into an anti-metastatic drug.

Dioscin suppresses human laryngeal cancer cells growth via induction of cell-cycle arrest and MAPK-mediated mitochondrial-derived apoptosis and inhibition of tumor invasion

The anti-cancer effects of dioscin have been widely reported. However, its effect on laryngeal cancer remains unknown. In the present paper, our results showed that dioscin markedly caused cell apoptosis and DNA damage, increased reactive oxygen species (ROS) level, induced S-phase arrest, and inhibited invasion of human laryngeal cancer HEp-2 and TU212 cells. Mechanism investigation showed that dioscin markedly up-regulated p53 level, and down-regulated cyclin-dependent kinase 2 (CDK2) and Cyclin A levels. In addition, dioscin significantly down-regulated the levels of p-ERK, Bcl-2, up-regulated the levels of p-JNK, p-p38, Bax, cleaved caspase-3/-9, and caused Cytochrome c release. Furthermore, U0126, an ERK1/2 inhibitor, markedly down-regulated Bcl-2 level, up-regulated the levels of Bax, cleaved caspase-3/9, and enhanced Cytochrome c release inducted by dioscin. While, SP600125 (one JNK inhibitor) and SB203580 (one p38 inhibitor) markedly up-regulated Bcl-2 level, down-regulated the levels of Bax, cleaved caspase-3/9, and obviously boosted Cytochrome c release induced by dioscin. Interestingly, dioscin also markedly down-regulated the levels of MMP2 and MMP9 associated with tumor invasion. Taken together, our study indicated that dioscin suppressed laryngeal cancer cells growth via inducting cell-cycle arrest, MAPK-mediated mitochondrial- derived apoptosis and inhibiting tumor invasion, which could be used as one potential candidate for the treatment of laryngeal cancer in the future.

Application of Hypoxia to Establish Epithelial-Mesenchymal Transition Models in Renal Cell Carcinoma Cell Lines

Purpose: To establish epithelial-mesenchymal transition (EMT) models in renal cell carcinoma cell lines by CoCl2-induced hypoxia. Materials and methods: The renal cell carcinoma cell lines A498 and 786-O were used in the experiment and CoCl2 was used to simulate hypoxia. The cancer cells were cultured with different concentrations of CoCl2. Morphology and cyto-activity changes were detected to obtain the optimal concentration of CoCl2 for simulating hypoxia. After CoCl2 treatment, the cells were subjected to Western blot analysis to test the expression of HIF-1α and the changes of EMT-related molecules (E-cadherin, fibronectin). Results: Cell conjunctions of CoCl2-treated groups were loose and scattered compared to the control. The effect of CoCl2 on A498 cell viability was not distinct at a low dosage, but when the concentration of CoCl2 reached 250 mM, cell activity gradually declined. In contrast, CoCl2 induced 786-O cell proliferation in the range of 50 mM- 200 mM, but it inhibited cell growth at dosages higher than 200 mM. The expression of E-cadherin was significantly down-regulated, and fibronectin was up-regulated in both A498 and 786-O cell lines under CoCl2-simulated hypoxia in comparison with normoxic conditions (P<0.01). Conclusions: EMT models of the renal cell carcinoma cell lines were successfully established by CoCl2-induced hypoxia. The models will help us further study the mechanisms of EMT and investigate novel therapeutic targets to inhibit tumor invasion and metastasis.

MicroRNA-663 suppresses cell invasion and migration by targeting transforming growth factor beta 1 in papillary thyroid carcinoma.

MicroRNA-663 (miR-663) has been detected in a large variety of tumor types; however, it still holds both tumor suppressive and oncogenic roles in different tumor types. The miRNA-CHIP microarray assay revealed downregulation of miR-663 in papillary thyroid carcinoma (PTC); however, the effect of miR-663 on PTC cell invasion and migration remains unknown. Accordingly, this study aimed to investigate the potential involvement of miR-663 in PTC. In this study, miR-663 expression level was measured via quantitative real-time PCR in 91 pairs of human PTC and adjacent normal tissues and in two human PTC cell lines. The effect of miR-663 on PTC cell invasion and migration were studied by transwell and wound healing assays. In addition, the miR-663 target was searched and the underlying mechanism was clarified by reporter assay and rescue experiment. The current study confirmed that miR-663 expression was inhibited in PTC tissue samples and PTC cell lines. There were statistically significant differences in expression of miR-663 with regard to age and tumor size. Upregulation of miR-663 suppressed PTC cell invasion and migration. Further study showed that transforming growth factor beta 1 (TGFβ1) was the direct target of miR-663 and mediated the effect of miR-663 on PTC development. By targeting TGFβ1, miR-663 efficiently regulates the expression of epithelial-mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs). The data indicated that miR-663 may suppress tumor invasion and migration by targeting TGFβ1 and regulate EMT progress of PTC cells.

Specific Exosomal microRNA Are Differentially Expressed Between High and Low-Risk Myeloma Suggesting They Are Pathogenically Important

Introduction Treating High Risk myeloma (HRMM) is an important clinical challenge and understanding the basis of its pathogenesis could offer new therapeutic options. At present very few clues exist as to what is crucially deregulated between HR and LR and micro RNA (miR) are prominent candidates. Since the first miRNA was discovered over 20 years ago, the important role of these small noncoding RNA molecules in multiple myeloma pathogenesis has been recognized. In addition to their function in regulating gene expression within their cell of origin, miR molecules encased in exosomes are also secreted into the circulation. In this setting exosomes can deliver their content to other cells throughout the body, and have been suggested to be a key factor mediating the interaction of the MM cells and their microenvironment. We have tested the hypothesis that miR content of exosomes in bone marrow serum of patients with myeloma have an impact on biological behavior and as such can distinguish between patients with GEP 70-defined high- and low-risk disease. Methods Exosomes were isolated from bone marrow serum using Invitrogen kits according to manufacturer's instructions. Aliquots from the resulting samples were analyzed using electron microscopy to confirm the presence of exosomes. The exosome preparations were spiked with the Caenorhabditis elegance miR mimetic Ce_miRNA39_1 as a control, and miR was subsequently isolated using miRNeasy Kit (Qiagen). The miR were converted to cDNA with polyA tailing, pre-amplified 10 cycles. Aliquots of the preamplified cDNA were loaded into the samples wells and primer pairs of 68 miR, reported to be differentially expressed in myeloma or other cancers, were loaded into the reagent wells of Fluidigm's 96x96 Dynamic Array IFCs (integrated fluidic circuit) and the arrays processed on a Fluidigm BioMark. Results were analyzed using the company's Real-Time PCR analysis software. The level of the 68 miRs were analyzed in preamplified exosomal miR cDNA from 13 healthy donors, and 76 untreated NDMM patients (54 low-risk, 22 high-risk as categorized by GEP 70 gene model). Results Electron microscopy analysis confirmed the presence of exosomes, sized between 50 and 150nm in all of the sample preparations. With a cutoff ratio of 1.5, 3 miRs were differentially expressed between HRMM and LRMM: miR-192, and 215 were present at a higher level in exosomes from LRMM (1.6, and 1.8 fold, respectively) than in HRMM, while miR 720 and 1308 were higher in HR MM (2.9 and 3.3 fold, respectively). Of the 4 differentially expressed miRs, 2 ( 192, and 1308) were 2-82 fold higher in MM bone marrow serum exosomes than in exosomes from the healthy donors, one (720) had equal levels, and one (miR-215) was not detected in healthy donor samples. Among the 68 miRs analyzed, 4 were differentially expressed between HR- and LRMM. miRNA 192 and 215 both target the MDM2/TP53 axis, and are lower in bone marrow serum exosomes from HRMM in comparison LRMM. In contrast, miR-720 and 1308 are higher in HRMM. In this context miR-720 inhibits tumor invasion in breast cancer and modulates proliferation in esophageal cancer; miR-1308 is a fragment of t-RNA, targets the apoptotic pathway, and has anti-apoptotic function. It has been reported that miR-137 is deregulated in solid tumors, and that overexpression can induce apoptosis in MM cell lines. It is interesting that it was present in bone marrow serum exosomes from only 2 low-risk myeloma patients and not in exosomes isolated from purified myeloma plasma cells from 12 high-risk patients. Conclusion These results indicate that exosomal microRNA are associated with the risk status of myeloma patients at presentation, either as a reflection of risk or as effectors. Their presence in protecting vesicles in the circulation indicates that miR have the capacity to modulate the properties of the microenvironment and myeloma cells in remote loci. To better elucidate the role of exosomal miR in the interaction of myeloma cells with the microenvironment it is important to determine the source of the exosomes. Figure 1. Figure 1. Disclosures Chen: University of Arkansas for Medical Sciences: Employment. Morgan:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Weismann Institute: Honoraria; MMRF: Honoraria; CancerNet: Honoraria; University of Arkansas for Medical Sciences: Employment; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Barlogie:Multiple Myeloma Research Foundation: Other: Travel Stipend; Dana Farber Cancer Institute: Other: Travel Stipend; International Workshop on Waldenström's Macroglobulinemia: Other: Travel Stipend; ComtecMed- World Congress on Controversies in Hematology: Other: Travel Stipend; European School of Haematology- International Conference on Multiple Myeloma: Other: Travel Stipend; Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Myeloma Health, LLC: Patents &amp; Royalties: Co-inventor of patents and patent applications related to use of GEP in cancer medicine licensed to Myeloma Health, LLC. Epstein:University of Arkansas for Medical Sciences: Employment.

Fucoidan protects hepatocytes from apoptosis and inhibits invasion of hepatocellular carcinoma by up-regulating p42/44 MAPK-dependent NDRG-1/CAP43

Fucoidan is a traditional Chinese medicine suggested to possess anti-tumor effects. In this study the anti-metastatic effects of fucoidan were investigated in vitro in human hepatocellular carcinoma (HCC) cells (Huh-7 and SNU-761) under normoxic and hypoxic conditions and in vivo using a distant liver metastasis model involving injection of MH134 cells into spleen via the portal vein. Its ability to protect hepatocytes against bile acid (BA)-induced apoptosis was investigated in primary hepatocytes. Fucoidan was found to suppress the invasion of HCC cells through up-regulation of p42/44 MAPK-dependent NDRG-1/CAP43 and partly, under normoxic conditions, through up-regulation of p42/44 MAPK-dependent VMP-1 expression. It also significantly decreased liver metastasis in vivo. As regards its hepatoprotective effect, fucoidan decreased BA-induced hepatocyte apoptosis as shown by the attenuation of caspase-8, and -7 cleavages and suppression of the mobilization of caspase-8 and Fas associated death domain (FADD) into the death-inducing signaling complex. In summary, fucoidan displays inhibitory effects on proliferation of HCC cells and protective effects on hepatocytes. The results suggest fucoidan is a potent suppressor of tumor invasion with hepatoprotective effects.

SIRT1 induces tumor invasion by targeting epithelial mesenchymal transition-related pathway and is a prognostic marker in triple negative breast cancer.

Absence of therapeutic targets poses a critical hurdle in improving prognosis for patients with triple negative breast cancer (TNBC). We evaluated interaction between SIRT1 and epithelial mesenchymal transition (EMT)-associated proteins as well as the role of combined protein expression as a predictor of lymph node metastasis and clinical outcome in TNBC through in vivo and vitro studies. Three hundred nineteen patients diagnosed with TNBC were chosen, immunohistochemical staining for SIRT1 and EMT-related markers' expression was performed on tissue microarrays, and in vitro experiments with each of the three human TNBC cell lines were carried out. The cohort was reclassified according to the use of adjuvant chemotherapy, tumor size, and AJCC stage to analyze the prognostic role of SIRT1 and EMT-related proteins' expression considering different therapeutic modalities and AJCC stages. Combination of four proteins including SIRT1 and three EMT-related proteins was revealed to be a statistically significant independent predictor of lymph node metastasis in the tumor size cohort as well as in the total patient population. Upon Cox regression analysis, increased expression level of the combined proteins correlated with decreased disease-free survival in the total patients as well as those who received adjuvant chemotherapy and those who had early stage breast cancer. In additional in vitro experiments, inhibition of SIRT1 expression with small interfering RNA (siRNA) suppressed tumor invasion in three different TNBC cell lines, and altered expression levels of EMT-related proteins following SIRT1 gene inhibition were identified on western blotting and fluorescence activated cell sorting (FACS) analysis; on the other hand, no change in expression levels of the cell cycle-related factors was observed. Our analysis showed the potential role of SIRT1 in association with EMT-related factors on tumor invasion, metastasis, and disease-free survival in TNBC, SIRT1, and associated EMT-related markers may offer a new prognostic indicator as well as a novel therapeutic candidate.

SL4, a chalcone-based compound, induces apoptosis in human cancer cells by activation of the ROS/MAPK signalling pathway.

SL4, a chalcone-based compound, exhibits clearly inhibitory effects on HIF-1 and has been shown to effectively suppress tumour invasion and angiogenesis in vitro and in vivo. Here, studies were conducted to determine SL4's anti-apoptotic effects and its underlying mechanisms, in human cancer cells. Cytotoxicity, apoptotic induction and its involved mechanisms of SL4 were investigated using normal cells, cancer cells and mouse xenograft models. The role of reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) signalling in SL4-induced apoptosis was explored by manipulating specific scavenger or signalling inhibitors, in cultured cells. SL4 significantly inhibited cell population growth of human cancer cell lines but exhibited lower cytotoxicity against normal cells. In addition, SL4 effectively induced apoptosis of Hep3B and MDA-MB-435 cells by activating procaspase-8, -9 and -3, and down-regulating expression levels of XIAP, but did not affect HIF-1 apoptosis-related targets, Survivin and Bcl-XL. Further study showed that SL4 also reduced mitochondrial membrane potential and promoted generation of ROS. ROS generation and apoptotic induction by SL4 were blocked by NAC, a scavenger of ROS, suggesting SL4-induced apoptosis via ROS accumulation. We also found that MAPKs, JNK and p38, but not ERK1/2, to be critical mediators in SL4-induced apoptosis. SP600125 and SB203580, specific inhibitors of JNK kinase and p38 kinase, significantly retarded apoptosis induced by SL4. Moreover, anti-oxidant NAC blocked activation of JNK and p38 induced by SL4, indicating that ROS may act as upstream signalling of JNK and p38 activation. It is noteworthy that animal studies revealed dramatic reduction (49%) in tumour volume after 11 days SL4 treatment. These data demonstrate that SL4 induced apoptosis in human cancer cells through activation of the ROS/MAPK signalling pathway, suggesting that it may be a novel lead compound, as a cancer drug candidate, with polypharmacological characteristics.

The role of the microenvironment in regulation of CSPG-driven invasive and non-invasive tumor growth in glioblastoma

Glioblastoma (GBM) is one of the most lethal type of brain cancer with poor survival time. GBM is characterized by infiltration of the cancer cells through the brain tissue while lower grade gliomas and other non-neural metastatic types form self-contained non-invasive lesions. Glycosylated chondroitin sulfate proteoglycans (CSPGs), acting as critical regulators of the tumor microenvironment, dramatically govern the spatiotemporal status of resident reactive astrocytes and activation of tumor-associated microglia. In this paper we develop a mathematical model to investigate the effect of the CSPG distribution on regulation of a fundamental switch between two distinct patterns: invasive and non-invasive tumors. We show that the model’s predictions agree with experimental results for a spherical glioma. The model specifically predicts that non-invasive tumor lesions are highly associated with a thick extracellular matrix (ECM) containing rich CSPGs, while the absence of glycosylated CSPGs results in diffusely infiltrative tumors. It is also shown that heavy CSPGs can drive the exodus of resident reactive astrocytes from the main tumor mass, and direct inhibition of tumor invasion by the astrogliotic capsule, leading to encapsulation of non-invasive lesions. However, stable residence of reactive astrocytes from GBM in the absence or low level of CSPGs presents a microenvironment favorable to diffuse infiltration due to loss of the primary (CSPG-induced cell-ECM bonding) and secondary (astrogliotic capsule) inhibitors. The mathematical model presents the clear role of the key tumor microenvironment in brain tumor invasion.

Increased Histone Deacetylase Activity Involved in the Suppressed Invasion of Cancer Cells Survived from ALA-Mediated Photodynamic Treatment.

Previously, we have found that cancer cells survived from 5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) have abnormal mitochondrial function and suppressed cellular invasiveness. Here we report that both the mRNA expression level and enzymatic activity of histone deacetylase (HDAC) were elevated in the PDT-derived variants with dysfunctional mitochondria. The activated HDAC deacetylated histone H3 and further resulted in the reduced migration and invasion, which correlated with the reduced expression of the invasion-related genes, matrix metalloproteinase 9 (MMP9), paternally expressed gene 1 (PEG1), and miR-355, the intronic miRNA. Using chromatin immunoprecipitation, we further demonstrate the reduced amount of acetylated histone H3 on the promoter regions of MMP9 and PEG1, supporting the down-regulation of these two genes in PDT-derived variants. These results indicate that HDAC activation induced by mitochondrial dysfunction could modulate the cellular invasiveness and its related gene expression. This argument was further verified in the 51-10 cybrid cells with the 4977 bp mtDNA deletion and A375 ρ0 cells with depleted mitochondria. These results indicate that mitochondrial dysfunction might suppress tumor invasion through modulating histone acetylation.

Metastasis Suppressors Regulate the Tumor Microenvironment by Blocking Recruitment of Prometastatic Tumor-Associated Macrophages.

Triple-negative breast cancer (TNBC) patients have the highest risk of recurrence and metastasis. Because they cannot be treated with targeted therapies, and many do not respond to chemotherapy, they represent a clinically underserved group. TNBC is characterized by reduced expression of metastasis suppressors such as Raf kinase inhibitory protein (RKIP), which inhibits tumor invasiveness. Mechanisms by which metastasis suppressors alter tumor cells are well characterized; however, their ability to regulate the tumor microenvironment and the importance of such regulation to metastasis suppression are incompletely understood. Here, we use species-specific RNA sequencing to show that RKIP expression in tumors markedly reduces the number and metastatic potential of infiltrating tumor-associated macrophages (TAM). TAMs isolated from nonmetastatic RKIP(+) tumors, relative to metastatic RKIP(-) tumors, exhibit a reduced ability to drive tumor cell invasion and decreased secretion of prometastatic factors, including PRGN, and shed TNFR2. RKIP regulates TAM recruitment by blocking HMGA2, resulting in reduced expression of numerous macrophage chemotactic factors, including CCL5. CCL5 overexpression in RKIP(+) tumors restores recruitment of prometastatic TAMs and intravasation, whereas treatment with the CCL5 receptor antagonist Maraviroc reduces TAM infiltration. These results highlight the importance of RKIP as a regulator of TAM recruitment through chemokines such as CCL5. The clinical significance of these interactions is underscored by our demonstration that a signature comprised of RKIP signaling and prometastatic TAM factors strikingly separates TNBC patients based on survival outcome. Collectively, our findings identify TAMs as a previously unsuspected mechanism by which the metastasis-suppressor RKIP regulates tumor invasiveness, and further suggest that TNBC patients with decreased RKIP activity and increased TAM infiltration may respond to macrophage-based therapeutics.

Isolation and characterization of novel RECK tumor suppressor gene splice variants.

Glioblastoma multiforme is the most common and lethal of the central nervous system glial-derived tumors. RECK suppresses tumor invasion by negatively regulating at least three members of the matrix metalloproteinase family: MMP-9, MMP-2, and MT1-MMP. A positive correlation has been observed between the abundance of RECK expression in tumor samples and a more favorable prognosis for patients with several types of tumors. In the present study, novel alternatively spliced variants of the RECK gene: RECK-B and RECK-I were isolated by RT-PCR and sequenced. The expression levels and profiles of these alternative RECK transcripts, as well as canonical RECK were determined in tissue samples of malignant astrocytomas of different grades and in a normal tissue RNA panel by qRT-PCR. Our results show that higher canonical RECK expression, accompanied by a higher canonical to alternative transcript expression ratio, positively correlates with higher overall survival rate after chemotherapeutic treatment of GBM patients. U87MG and T98G cells over-expressing the RECK-B alternative variant display higher anchorage-independent clonal growth and do not display modulation of, respectively, MMP-2 and MMP-9 expression. Our findings suggest that RECK transcript variants might have opposite roles in GBM biology and the ratio of their expression levels may be informative for the prognostic outcome of GBM patients.

Anticancer mechanism of scutellarin

Scutellarin (SC), a botanical extract, possesses a variety of suppressing free radical generation, anti-inflammatory, cardioprotection and anti-virus activity. Recently, many studies show that SC has inhibitory effects on the growth of many tumors and is a kind of potential anti-tumor drug. Its anti-tumor mechanisms mainly include inducing apoptosis, arresting cell cycle, enhancing the adhesion between cells, inhibiting tumor invasion, reversing multidrug resistance, anti-angiogenesis and so on. Key words: Antineoplastic agents; Apoptosis; Scutellarin

HMGN5 blockade by siRNA enhances apoptosis, suppresses invasion and increases chemosensitivity to temozolomide in meningiomas.

The high-mobility group nucleosome-binding protein-5 (HMGN5) is frequently overexpressed in various malignant cancers. However, the potential correlation between HMGN5 and prognosis in patients with meningiomas remains unknown. In the present study, we explored the expression of HMGN5 in meningiomas with immunohistochemistry and correlated the results to the patient outcome. Potential effects of HMGN5 on tumor growth, apoptosis and invasion were also examined in representative cell lines (IOMM-Lee and CH157) by downregulating HMGN5 with RNA interference (siRNA). We demonstrate that there is a positive association between HMGN5 expression and meningioma histological grade. Statistical analysis reveals that lower HMGN5 expression predict lower meningioma recurrence. In addition, downregulation of HMGN5 inhibits IOMM-Lee and CH157 cell proliferation, enhances cell apoptosis and suppresses tumor invasion. Our results further revealed that HMGN5 inhibition decreased P-glycoprotein (MDR-1) expression without affecting multidrug resistance associated proteins 1 (MRP-1) expression to increase chemosensitivity to temozolomide (TMZ) of meningioma cells. Collectively, this study indicates that HMGN5 is a novel target for developing effective therapeutic strategies for malignant meningiomas.