Jungwhoi Lee

Kaempferol Inhibits Pancreatic Cancer Cell Growth and Migration through the Blockade of EGFR-Related Pathway In Vitro

Pancreatic cancer is one of the most appalling cancers with a pessimistic prognosis. Despite many therapies, there has been no improvement of survival rates. In this study, we assessed the anti-cancer effects of kaempferol, a well known flavonoid having functional bio-activity against various malignant tumors. Kaempferol had anti-cancer effects on Miapaca-2, Panc-1, and SNU-213 human pancreatic cancer cells. In a dose-dependent manner, kaempferol decreased viability of these pancreatic cancer cells by increasing apoptosis. In particular, kaempferol effectively inhibited the migratory activity of human pancreatic cancer cells at relatively low dosages without any toxicity. The anti-cancer effect of kaempferol was mediated by inhibition of EGFR related Src, ERK1/2, and AKT pathways. These results collectively indicate that kaempferol, a phytochemical ingredient reported to have anti-viability and anti-oxidant properties, can act as a safety anti-migration reagent in human pancreatic cancer cells, which provide the rationale for further investigation of kaempferol as a strong candidate for the potential clinical trial of malignant pancreatic cancers.

Quercetin 3-O-glucoside suppresses epidermal growth factor–induced migration by inhibiting EGFR signaling in pancreatic cancer cells

Pancreatic cancer is one of the most dangerous cancers and is associated with a grave prognosis. Despite increased knowledge of the complex signaling networks responsible for progression of pancreatic cancer, many challenging therapies have fallen short of expectations. In this study, we examined the anti-migratory effect of quercetin 3-O-glucoside in epidermal growth factor–induced cell migration by inhibiting EGF receptor (EGFR) signaling in several human pancreatic cancer cell lines. Treatment with quercetin, quercetin 3-O-glucoside, and quercetin 7-O-glucoside differentially suppressed epidermal growth factor–induced migration activity of human pancreatic cancer cells. In particular, quercetin 3-O-glucoside strongly inhibited the infiltration activity of pancreatic cancer cells in a dose-dependent manner. Furthermore, quercetin 3-O-glucoside exerted the anti-migratory effect even at a relatively low dose compared with other forms of quercetin. The anti-tumor effects of quercetin 3-O-glucoside were mediated by selectively inhibiting the EGFR-mediated FAK, AKT, MEK1/2, and ERK1/2 signaling pathway. Combinatorial treatment with quercetin 3-O-glucoside plus gemcitabine showed the synergistic anti-migratory effect on epidermal growth factor–induced cell migration in human pancreatic cancer cell lines. These results suggest that quercetin 3-O-glucoside has potential for anti-metastatic therapy in human pancreatic cancer.

Quercetin-3-O-glucoside suppresses pancreatic cancer cell migration induced by tumor-deteriorated growth factors in vitro

Analysis using Universal exPress Codes (UPCs) with the public microarray database GEO indicates significantly higher mRNA expressions of VEGF-A, bFGF, and bFGFR2 in pancreatic cancers than those in normal pancreatic tissues. Human pancreatic cancer cell line CFPAC-1 and SNU-213 had relatively differential sensitivity to exogenous VEGF-A, bFGF, and TGF-β1 in migration property. Treatment of quercetin-3-O-glucoside suppressed the migratory activity induced by TGF-β and VEGF-A even at relatively low dosages in CFPAC-1, but not in bFGF-activated SNU-213 cells. However, high dosages of quercetin-3-O-glucoside sufficiently suppressed the migratory activity induced by bFGF in SNU-213 cells. Furthermore, co-treatment with low dose of gemcitabine plus quercetin-3-O-glucoside showed synergistic inhibition effects on the infiltrate activity induced by bFGF in CFPAC-1 and SNU-213 cells. These results collectively suggested that quercetin-3-O glucoside could act as an inhibitor of local metastasis induced by various growth factors in pancreatic cancers and be an effective adjuvant to boost chemotherapeutic efficacy of gemcitabine, currently used in pancreatic cancers.

DUSP28 links regulation of Mucin 5B and Mucin 16 to migration and survival of AsPC-1 human pancreatic cancer cells.

The prognosis of pancreatic cancer has not improved despite considerable and continuous effort. Dual-specificity phosphatase 28 (DUSP28) is highly expressed in human pancreatic cancers and exerts critical effects. However, knowledge of its function in pancreatic cancers is extremely limited. Here, we demonstrate the peculiar role of DUSP28 in pancreatic cancers. Analysis using the Gene Expression Omnibus public microarray database indicated higher DUSP28, MUC1, MUC4, MUC5B, MUC16 and MUC20 messenger RNA (mRNA) levels in pancreatic cancers compared with normal pancreas tissues. DUSP28 expression in human pancreatic cancer correlated positively with those of MUC1, MUC4, MUC5B, MUC16 and MUC20. In contrast, there were no significant correlations between DUSP28 and mucins in normal pancreas tissues. Decreased DUSP28 expression resulted in down-regulation of MUC5B and MUC16 at both the mRNA and protein levels; furthermore, transfection with small interfering RNA (siRNA) for MUC5B and MUC16 inhibited the migration and survival of AsPC-1 cells. In addition, transfection of siRNA for MUC5B and MUC16 resulted in a significant decrease in phosphorylation of FAK and ERK1/2 compared with transfection with scrambled-siRNA. These results collectively indicate unique links between DUSP28 and MUC5B/MUC16 and their roles in pancreatic cancer; moreover, they strongly support a rationale for targeting DUSP28 to inhibit development of malignant pancreatic cancer.

Aqueous Extraction of Citrus unshiu Peel Induces Proangiogenic Effects Through the FAK and ERK1/2 Signaling Pathway in Human Umbilical Vein Endothelial Cells.

Citrus unshiu peel has been used empirically as a traditional medicine to improve bronchial asthma and blood circulation in northeast Asian nations, including Korea, Japan, and China. In this study, we report the proangiogenic effects of the aqueous extract of Citrus unshiu peel (AECUP). In human umbilical vein endothelial cells, AECUP significantly induced cellular migration and capillary tube formation. We also demonstrated that AECUP markedly increased the phosphorylation of FAK and ERK1/2 through the integrin signaling pathway. Additionally, we identified that narirutin and hesperidin were major constituents of AECUP and both showed proangiogenic effects, but at different levels. Collectively, these results suggest that the AECUP may have potential as a therapeutic agent for improving angiogenic functions with reduced harmful side effects.

Combined inhibition of vascular endothelial growth factor receptor signaling with temozolomide enhances cytotoxicity against human glioblastoma cells via downregulation of Neuropilin-1.

Glioblastoma multiforme (GBM) is the most common and aggressive type of primary brain tumor with grave prognosis. Despite the growing understanding of the complex signaling networks responsible for the initiation and progression of GBM, many experimental therapies have fallen short of their treatment goals. In the present study, we investigated the novel molecular mechanisms responsible for synergistic action of temozolomide (TMZ) and anti-VEGF therapy in GBM cells. We tested the combined effects of TMZ and VEGF blockade in four human GBM cell lines: TMZ-sensitive U251-MG and U373-MG cells, and TMZ-resistant CRT-MG and LN215-MG cells, which correlated with MGMT promoter methylation status. Treatment of TMZ along with a sublethal dosage range of SU1498, a chemical inhibitor of the VEGF receptor signaling, induced significant cell death in both TMZ-sensitive and TMZ-resistant GBM cells without changing the status of the MGMT promoter methylation. Treatment with TMZ specifically reduced the expression of NRP-1, a coreceptor of VEGF but not those of VEGF-R1 and VEGF-R2. We further confirmed the key role of NRP-1 by showing that the reduction of NRP-1 by siRNA also increased the SU1498-induced cytotoxicity of LN215-MG. These results collectively indicate that combined treatment of TMZ can sensitize GBM cells to blockade of autocrine VEGF signaling through specific down-regulation of NRP-1, which provide a rationale for further evaluation and a potential clinical trial of combinatorial therapy of TMZ and SU1498 or other VEGF inhibitors for intractable brain tumors.

DUSP28 is a novel biomarker responsible for aggravating malignancy via the autocrine signaling pathways in metastatic pancreatic cancer

Pancreatic cancer remains one of the most dangerous cancers with a grave prognosis. We previously reported that pancreatic cancer cells can secrete dual specificity phosphatise 28 (DUSP28) to the cultured medium. However, its biological function is poorly understood. Here, we have identified the function of DUSP28 in human metastatic pancreatic cancer. Treatment with recombinant DUSP28 (rDUSP28) significantly increased the migration, invasion, and viability of metastatic pancreatic cancer cells through the activation of CREB, AKT, and ERK1/2 signaling pathways. Furthermore, rDUSP28 acted as an oncogenic reagent through the interaction with integrin α1 in metastatic pancreatic cancer cells. In addition, rDUSP28 induced pro-angiogenic effects in human umbilical vein endothelial cells (HUVECs). Administration of rDUSP28 also produced tumor growth in vivo. Notably, sDUSP28 can easily be detected by immunoassay. The results establish the rationale for sDUSP28 as a promising therapeutic target and biomarker for metastatic pancreatic cancer patients.

Autocrine DUSP28 signaling mediates pancreatic cancer malignancy via regulation of PDGF-A

Pancreatic cancer remains one of the most deadly cancers with a grave prognosis. Despite continuous efforts to improve remedial values, limited progress has been made. We have reported that dual specificity phosphatase 28 (DUSP28) has a critical role of chemo-resistance and migration in pancreatic cancers. However, its mechanism remains unclear. Here, we further clarify the function of DUSP28 in pancreatic cancers. Analysis using a public microarray database and in vitro assay indicated a critical role of platelet derived growth factor A (PDGF-A) in pancreatic cancer malignancy. PDGF-A was positively regulated by DUSP28 expression at the mRNA and protein levels. Enhanced DUSP28 sensitized pancreatic cancer cells to exogenous PDGF-A treatment in migration, invasion, and proliferation. Transfection with siRNA targeting DUSP28 blunted the influence of administered PDGF-A by inhibition of phosphorylation of FAK, ERK1/2, and p38 signalling pathways. In addition, DUSP28 and PDGF-A formed an acquired autonomous autocrine-signaling pathway. Furthermore, targeting DUSP28 inhibited the tumor growth and migratory features through the blockade of PDGF-A expression and intracellular signaling in vivo. Our results establish novel insight into DUSP28 and PDGF-A related autonomous signaling pathway in pancreatic cancer.

Abstract 921: Pericellular-interactions promote malignant progression of glioblastoma via novel NOTCH-1/HIF-1α pathway

Malignant tumors generally develop hypoxic condition in the core region of tumor mass, which induces stabilization of hypoxia inducible factor-1 alpha (HIF-1α) by preventing proteasome-dependent degradation. HIF-1α has been shown to regulate various oncogenes for malignant progression of many types of tumors including glioblastoma multiforme (GBM). In the present study, we showed that cell-to-cell interactions at high density can induce malignant transformation of tumor cells by activation of HIF-1α even under normoxic condition. To delineate the biological effect of cell culture density, we maintained cancer cells in different density. Four types of GBM cell lines (U251-MG, LN215-MG, U373-MG, and CRT-MG) were used to examine the oncogenic phenotypes of cancer cells cultured in different densities. Cells cultured in a high-density condition showed higher rate of proliferation and migration activity and higher resistance to temozolomide, an anti-cancer drug commonly used for GBM treatment. We found that the pericellular interactions stimulate the cleavage of notch-1 intracellular domain (NICD), and the cleaved NICD protects the HIF-1α from hydroxylation and subsequent proteasomal degradation, resulting in nuclear translocation of HIF-1α. Collectively, we suggest that the cell-cell interactions in high-density culture conditions induce NICD-mediated HIF-1α activation, which leads to malignant phenotypic changes. Therefore, treatment of gamma-secretase inhibitor (GSI), which can block NOTCH-1 signaling pathway, in combination with TMZ could be a promising therapeutic strategy in TMZ-resistant tumor cells. This research was supported by a grant of the Korea Health Technology RD 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 921.