Blockade of Rac1 Activity Induces G1 Cell Cycle Arrest or Apoptosis in Breast Cancer Cells through Downregulation of Cyclin D1, Survivin, and X-Linked Inhibitor of Apoptosis Protein

Yoshida, Tatsushi; Zhang, Yaqin; Rosado, Leslie A. Rivera; Chen, Junjie; Khan, Tahira; Moon, Sun Young; Zhang, Baolin

doi:10.1158/1535-7163.mct-09-0906

Cited by 89 publications

(74 citation statements)

References 61 publications

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“…Blockade of RAC1 signalling in tissue remodelling promotes the accumulation of type I collagen due to decreased collagenase activity (Igata et al, 2010). In addition, reduction of RAC1 was observed in breast cancer cells induced by a pharmacologic inhibitor, NSC27366 which resulted in tumour cell toxicity and apoptosis (Yoshida et al, 2010). TGM2 is conserved in the cytoplasm, nucleus and plasma membrane (Milakovic et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Expression Profile of Genes Modulated by Aloe emodin in Human U87 Glioblastoma Cells

Haris

Ismail²,

Idris³

et al. 2014

Asian Pacific Journal of Cancer Prevention

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Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with 58.6 µg/ml for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.

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Section: Discussionmentioning

confidence: 99%

Expression Profile of Genes Modulated by Aloe emodin in Human U87 Glioblastoma Cells

Haris

Ismail²,

Idris³

et al. 2014

Asian Pacific Journal of Cancer Prevention

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“…2C), probably because it both regulates and is regulated by the cell cycle. Inhibition of Rac1 induces G1 cellcycle arrest (23), and Rac1 is excluded from the nucleus in early G1 (24). This combination accounts for its disproportionate decrease in the nucleus when it is knocked down.…”

Section: Discussionmentioning

confidence: 99%

Rac1/osmosensing scaffold for MEKK3 contributes via phospholipase C-γ1 to activation of the osmoprotective transcription factor NFAT5

Zhou

Yokoyama

Burg

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Separate reports that hypertonicity activates p38 via a Rac1-OSM-MEKK3-MKK3-p38 pathway and that p38α contributes to activation of TonEBP/OREBP led us to the hypothesis that Rac1 might activate TonEBP/OREBP via p38. The present studies examine that possibility. High NaCl is hypertonic. We find that siRNA knockdown of Rac1 reduces high NaCl-induced increase of TonEBP/OREBP transcriptional activity (by reducing its transactivating activity but not its nuclear localization). Similarly, siRNA knockdown of osmosensing scaffold for MEKK3 (OSM) also reduces high NaCl-dependent TonEBP/OREBP transcriptional and transactivating activities. Simultaneous siRNA knockdown of Rac1 and OSM is not additive in reduction of TonEBP/OREBP transcriptional activity, indicating a common pathway. However, siRNA knockdown of MKK3 does not reduce TonEBP/OREBP transcriptional activity, although siRNA knockdown of MKK6 does. Nevertheless, the effect of Rac1 on TonEBP/OREBP is also independent of MKK6 because it occurs in MKK6-null cells. Furthermore, we find that siRNA knockdown of Rac1 or OSM actually increases activity (phosphorylation) of p38, rather than decreasing it, as previously reported. Thus, the effect of Rac1 on TonEBP/OREBP is independent of p38. We find instead that phospholipase C-γ1 (PLC-γ1) is involved. When transfected into PLC-γ1-null mouse embryonic fibroblast cells, catalytically active Rac1 does not increase TonEBP/OREBP transcriptional activity unless PLC-γ1 is reconstituted. Similarly, dominant-negative Rac1 also does not inhibit TonEBP/OREBP in PLC-γ1-null cells unless PLC-γ1 is reconstituted. We conclude that Rac1/OSM supports TonEBP/ OREBP activity and that this activity is mediated via PLC-γ1, not p38. osmotic stress | MAPK H ypertonicity (e.g., high NaCl) activates the transcription factor TonEBP/OREBP (also known as NFAT5), resulting in increased expression of osmoprotective genes (1). Hypertonicity increases TonEBP/OREBP activity by increasing its abundance (1), transactivating activity (1), nuclear localization (1), and phosphorylation (2, 3). The regulatory increase of phosphorylation depends on both increased kinase activity and reduced phosphatase activity (4, 5). The stress-activated MAP kinase p38 has been extensively studied in this regard, but understanding its role has been complicated because hypertonicity activates two different p38s, namely p38α (MAPK14) and p38δ (MAPK13), which have opposite effects on TonEBP/OREBP activity: p38α increases TonEBP/OREBP activity and p38δ decreases it (6). Furthermore, the phosphospecific antibodies commonly used to measure p38 activity do not directly distinguish between p38α activity and p38δ activity, nor do some forms of inhibition that have been used (6). In this article, we will continue to refer to "p38" unless p38α and p38δ are distinguished. Hypertonicity activates p38α via the upstream kinase MKK3 (MAP2K3) or MKK6 (MAP2K6) (7), and p38α and MEKK3 (MAP3K3) contribute to hypertonicity-induced activation of TonEBP/OREBP (6, 8, 9). Thus, p38α contributes to To...

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“…Statins activate cancer cell death, including apoptosis, via a reduction of GGPP and FPP levels. Additionally, Ras-related C3 botulinum toxin substrate 1 (RAC1) regulates and modulates several signaling pathways that control cellular proliferation (24), and direct inhibition of RAC1 activity or gene expression induces cell cycle arrest and apoptosis in breast cancer cells (25).…”

Section: Introductionmentioning

confidence: 99%

Simvastatin potentiates doxorubicin activity against MCF‑7 breast cancer cells

2017

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Abstract. Simvastatin is a low density lipoprotein-lowering drug that is widely used to prevent and treat cardiovascular disease by inhibiting the mevalonate pathway. Simvastatin also exhibits inhibitory effects on a number of types of cancer. In the present study, the effects of simvastatin on the activity of doxorubicin in the breast cancer MCF-7 cell line, and the mechanisms by which this interaction occurs were investigated. The effect of simvastatin and doxorubicin treatment, alone and in combination, on the growth of MCF-7 cells was evaluated by a sulforhodamine B and colony formation assay. To delineate the mechanisms of cell death, the following parameters were measured: Reactive oxygen species (ROS) production using the fluorescence probe dihydroethidium; caspase 3 activity by the fluorometry method; gene expression by quantitative polymerase chain reaction; and apoptotic-and proliferative-related protein levels by western blotting. MCF-7 cell proliferation was significantly suppressed by 24-48 h treatment with simvastatin alone. Doses of 10-50 µM simvastatin also enhanced the cytotoxicity of doxorubicin against MCF-7 cells in a dose-dependent manner, and decreased the colony-forming ability of MCF-7 cells. Simvastatin alone or in combination with doxorubicin significantly increased ROS levels. Combination treatment significantly decreased expression of the cell cycle regulatory protein Ras-related C3 botulinum toxin substrate 1 and numerous downstream proteins including cyclin-dependent kinase (Cdk) 2, Cdk4 and Cdk6. Additionally, simvastatin in combination with doxorubicin significantly induced expression of the cyclin-dependent kinase inhibitor p21, increased cytochrome c and caspase 3 expression and reduced cyclin D1 expression. In conclusion, simvastatin acts synergistically with the anticancer drug doxorubicin against MCF-7 cells, possibly through a downregulation of the cell cycle or induction of apoptosis. Although additional studies are required, simvastatin and doxorubicin combination may be a reasonable regimen for the treatment of breast cancer.

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Blockade of Rac1 Activity Induces G1 Cell Cycle Arrest or Apoptosis in Breast Cancer Cells through Downregulation of Cyclin D1, Survivin, and X-Linked Inhibitor of Apoptosis Protein

Cited by 89 publications

References 61 publications

Expression Profile of Genes Modulated by Aloe emodin in Human U87 Glioblastoma Cells

Expression Profile of Genes Modulated by Aloe emodin in Human U87 Glioblastoma Cells

Rac1/osmosensing scaffold for MEKK3 contributes via phospholipase C-γ1 to activation of the osmoprotective transcription factor NFAT5

Simvastatin potentiates doxorubicin activity against MCF‑7 breast cancer cells

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