The Inhibitory Effect of (−)-Epigallocatechin Gallate on Activation of the Epidermal Growth Factor Receptor Is Associated with Altered Lipid Order in HT29 Colon Cancer Cells

Adachi, Seiji; Nagao, Tomokazu; Ingólfsson, Helgi I.; Maxfield, Frederick R.; Andersen, Olaf S.; Kopelovich, Levy; Weinstein, I. Bernard

doi:10.1158/0008-5472.can-07-0411

Cited by 188 publications

(162 citation statements)

References 45 publications

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“…Protein extracts were examined by Western blot analysis as previously described (33). The protein was fractionated and transferred onto an Immune-Blot PVDF membrane (Bio-Rad).…”

Section: Methodsmentioning

confidence: 99%

Ultraviolet Irradiation Can Induce Evasion of Colon Cancer Cells from Stimulation of Epidermal Growth Factor

Adachi

Yasuda

Nakashima

et al. 2011

Journal of Biological Chemistry

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Receptor down-regulation is the most prominent regulatory system of EGF receptor (EGFR) signal attenuation and a critical target for therapy against colon cancer, which is highly dependent on the function of the EGFR. In this study, we investigated the effect of ultraviolet-C (UV-C) on down-regulation of EGFR in human colon cancer cells (SW480, HT29, and DLD-1). UV-C caused inhibition of cell survival and proliferation, concurrently inducing the decrease in cell surface EGFR and subsequently its degradation. UV-C, as well as EGFR kinase inhibitors, decreased the expression level of cyclin D1 and the phosphorylated level of retinoblastoma, indicating that EGFR down-regulation is correlated to cell cycle arrest. Although UV-C caused a marked phosphorylation of EGFR at Ser-1046/1047, UV-C also induced activation of p38 MAPK, a stress-inducible kinase believed to negatively regulate tumorigenesis, and the inhibition of p38 MAPK canceled EGFR phosphorylation at Ser-1046/1047, as well as subsequent internalization and degradation, suggesting that p38 MAPK mediates EGFR down-regulation by UV-C. In addition, phosphorylation of p38 MAPK induced by UV-C was mediated through transforming growth factor-␤-activated kinase-1. Moreover, pretreatment of the cells with UV-C suppressed EGF-induced phosphorylation of EGFR at tyrosine residues in addition to cell survival signal, Akt. Together, these results suggest that UV-C irradiation induces the removal of EGFRs from the cell surface that can protect colon cancer cells from oncogenic stimulation of EGF, resulting in cell cycle arrest. Hence, UV-C might be applied for clinical strategy against human colon cancers. Members of the EGF receptor (EGFR)2 family, which are frequently overexpressed in several types of human cancers, including cancers of the lung (1), head and neck (2), prostate (3), breast (4), pancreas (5), and colon (6), have been associated with abnormal growth of these tumors. It is well known that exposure of cells to EGF results in rapid autophosphorylation of EGFR molecules at the cell surface (7-10), which upon activation lead to cell proliferation, motility, and enhanced survival (11). There are several mechanisms by which EGFR becomes oncogenic including: 1) increased EGFR expression levels, 2) autocrine and/or paracrine growth factor loops, 3) heterodimerization with other EGFR family members and crosstalk with heterologous receptor systems, 4) defective receptor down-regulation, and 5) activating mutations (12). In clinical trials, increasing evidence shows the efficacy of EGFR-targeted agents, including monoclonal antibodies on the one hand and tyrosine kinase inhibitors on the other (13).Following activation, the ligand-receptor complexes are internalized and then enter endosomes, where the receptors and their ligands are sorted to various intracellular destinations (14). Thus, some receptors can be recycled back to the cell surface via early endosomes, and others are targeted to late endosomes and lysosomes for proteolytic degradation. There is increasin...

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“…Protein extracts were examined by Western blot analysis as previously described (33). The protein was fractionated and transferred onto an Immune-Blot PVDF membrane (Bio-Rad).…”

Section: Methodsmentioning

confidence: 99%

Ultraviolet Irradiation Can Induce Evasion of Colon Cancer Cells from Stimulation of Epidermal Growth Factor

Adachi

Yasuda

Nakashima

et al. 2011

Journal of Biological Chemistry

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“…1C) analyses revealed a dosedependent increase in cell surface ceramide levels in U266 cells following EGCG treatment. Displacement of cholesterol from the lipid raft on the plasma membrane occurs after generation of ceramide by ASM (17), and EGCG has been shown to induce disruption of cholesterol-rich lipid rafts in colon cancer cells (27). Therefore, we next investigated the involvement of ASM in EGCGinduced disruption of lipid raft domains by staining with the lipid-mimetic dialkyl-indocarbocyanine (DilC16) and using a cold Triton X-100 solubility assay ( Fig.…”

Section: Activated Asm Induces Lipid Raft Disruptionmentioning

confidence: 99%

Sphingosine Kinase-1 Protects Multiple Myeloma from Apoptosis Driven by Cancer-Specific Inhibition of RTKs

Tsukamoto

Huang

Kumazoe

et al. 2015

Molecular Cancer Therapeutics

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Activation of acid sphingomyelinase (ASM) leads to ceramide accumulation and induces apoptotic cell death in cancer cells. In the present study, we demonstrate that the activation of ASM by targeting cancer-overexpressed 67-kDa laminin receptors (67LR) induces lipid raft disruption and inhibits receptor tyrosine kinase (RTK) activation in multiple myeloma cells. Sphingosine kinase 1 (SphK1), a negative regulator of ceramide accumulation with antiapoptotic effects, was markedly elevated in multiple myeloma cells. The silencing of SphK1 potentiated the apoptotic effects of the green tea polyphenol epigallocatechin-3-O-gallate (EGCG), an activator of ASM through 67LR. Furthermore, the SphK1 inhibitor safingol synergistically sensitized EGCG-induced proapoptotic cell death and tumor suppression in multiple myeloma cells by promoting the prevention of RTK phosphorylation and activation of death-associated protein kinase 1 (DAPK1). We propose that targeting 67LR/ASM and SphK1 may represent a novel therapeutic strategy against multiple myeloma.

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“…The cells were lysed in lysis buffer [20 mM Tris (pH 7.5), 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, 1% Triton X-100, 2.5 mM sodium pyrophosphate, 50 mM NaF, 50 mM HEPES, 1 mM Na 3 VO 4 and 2 mM phenylmethylsulfonyl fluoride (PMSF)] and scraped from the Petri dishes. Protein extracts were then examined by Western blot analysis as previously described (24). The antibodies used in these studies were anti-EGFR, anti-GAPDH (Santa Cruz Biotechnology, Santa Cruz, CA), anti-phospho-EGFR (Ser1046/7), anti-p44/p42 MAPK, anti-phospho-p44/p42 MAPK, anti-phospho-p38 MAPK, anti-p38 MAPK, antiphospho-stress-activated protein kinase/c-Jun-N-terminal kinase (SAPK/JNK) and anti-SAPK/JNK (Cell Signaling, Beverly, MA).…”

Section: Methodsmentioning

confidence: 99%

HSP90 inhibitors induce desensitization of EGF receptor via p38 MAPK-mediated phosphorylation at Ser1046/1047 in human pancreatic cancer cells

Adachi

Yasuda²,

Nakashima³

et al. 2010

Oncol Rep

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Abstract. Heat shock protein (HSP) 90 is known to be a molecular chaperone whose association is required for the stability and function of oncogenic protein including epidermal growth factor receptor (EGFR) that promotes cancer cell growth. Therefore, HSP90 is a promising target for therapy against cancer including in the pancreas, some of which are highly dependent on EGFR. We investigated the effects of HSP90 inhibitors on cytotoxicity and desensitization of EGFR in human pancreatic cancer cells (KP3, BxPc3 and AsPc1). 17-allylamino-17-demethoxy-geldanamycin (17-AAG), an inhibitor of HSP90, caused desensitization of EGFR in a time-dependent manner, concurrently inducing phosphorylation of EGFR at Ser1046/ 1047 (Ser1046/7), a site which plays an important role in EGFR desensitization in these pancreatic cancer cells. We also found similar effects in KP3 cells treated with other HSP90 inhibitors, geldanamycin and 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17-DMAG). In KP3 cells, 17-AAG induced activation of either p44/p42 mitogenactivated protein kinase (MAPK) or p38 MAPK. Interestingly, whereas the inhibition of p44/p42 MAPK attenuated neither phosphorylation of EGFR at Ser1046/7 nor desensitization of EGFR, the phosphorylation at Ser1046/7 induced by 17-AAG was markedly attenuated by the inhibition of p38 MAPK, indicating that p38 MAPK induced this phosphorylation. Moreover, the inhibition of p38 MAPK significantly attenuated 17-AAG-induced EGFR desensitization. These results strongly suggest that EGFR phosphorylation at Ser1046/7 via activation of p38 MAPK induced by HSP90 inhibitors plays a pivotal role in EGFR desensitization in human pancreatic cancer cells.

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The Inhibitory Effect of (−)-Epigallocatechin Gallate on Activation of the Epidermal Growth Factor Receptor Is Associated with Altered Lipid Order in HT29 Colon Cancer Cells

Cited by 188 publications

References 45 publications

Ultraviolet Irradiation Can Induce Evasion of Colon Cancer Cells from Stimulation of Epidermal Growth Factor

Ultraviolet Irradiation Can Induce Evasion of Colon Cancer Cells from Stimulation of Epidermal Growth Factor

Sphingosine Kinase-1 Protects Multiple Myeloma from Apoptosis Driven by Cancer-Specific Inhibition of RTKs

HSP90 inhibitors induce desensitization of EGF receptor via p38 MAPK-mediated phosphorylation at Ser1046/1047 in human pancreatic cancer cells

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