Targeting LRRC15 Inhibits Metastatic Dissemination of Ovarian Cancer

Dissemination of ovarian cancer cells can lead to inoperable metastatic lesions in the bowel and omentum that cause patient death. Here we show that LRRC15, a type-I 15-leucine-rich repeat-containing membrane protein, highly overexpressed in ovarian cancer bowel metastases compared with matched primary tumors and acts as a potent promoter of omental metastasis. Complementary models of ovarian cancer demonstrated that LRRC15 expression leads to inhibition of anoikis-induced cell death and promotes adhesion and invasion through matrices that mimic omentum. Mechanistically, LRRC15 interacted with β1-integrin to stimulate activation of focal adhesion kinase (FAK) signaling. As a therapeutic proof of concept, targeting LRRC15 with the specific antibody-drug conjugate ABBV-085 in both early and late metastatic ovarian cancer cell line xenograft models prevented metastatic dissemination, and these results were corroborated in metastatic patient-derived ovarian cancer xenograft models. Furthermore, treatment of 3D-spheroid cultures of LRRC15-positive patient-derived ascites with ABBV-085 reduced cell viability. Overall, these data uncover a role for LRRC15 in promoting ovarian cancer metastasis and suggest a novel and promising therapy to target ovarian cancer metastases.

Significance: This study identifies that LRRC15 activates β1-integrin/FAK signaling to promote ovarian cancer metastasis and shows that the LRRC15-targeted antibody-drug conjugate ABBV-085 suppresses ovarian cancer metastasis in preclinical models.

Genes associated with bowel metastases in ovarian cancer

OBJECTIVE

This study is designed to identify genes and pathways that could promote metastasis to the bowel in high-grade serous ovarian cancer (OC) and evaluate their associations with clinical outcomes.

METHODS

We performed RNA sequencing of OC primary tumors (PTs) and their corresponding bowel metastases (n = 21 discovery set; n = 18 replication set). Differentially expressed genes (DEGs) were those expressed at least 2-fold higher in bowel metastases (BMets) than PTs in at least 30% of patients (P < .05) with no increased expression in paired benign bowel tissue and were validated with quantitative reverse transcription PCR. Using an independent OC cohort (n = 333), associations between DEGs in PTs and surgical and clinical outcomes were performed. Immunohistochemistry and mouse xenograft studies were performed to confirm the role of LRRC15 in promoting metastasis.

RESULTS

Among 27 DEGs in the discovery set, 21 were confirmed in the replication set: SFRP2, Col11A1, LRRC15, ADAM12, ADAMTS12, MFAP5, LUM, PLPP4, FAP, POSTN, GRP, MMP11, MMP13, C1QTNF3, EPYC, DIO2, KCNA1, NETO1, NTM, MYH13, and PVALB. Higher expression of more than half of the genes in the PT was associated with an increased requirement for bowel resection at primary surgery and an inability to achieve complete cytoreduction. Increased expression of LRRC15 in BMets was confirmed by immunohistochemistry and knockdown of LRRC15 significantly inhibited tumor progression in mice.

CONCLUSIONS

We identified 21 genes that are overexpressed in bowel metastases among patients with OC. Our findings will help select potential molecular targets for the prevention and treatment of malignant bowel obstruction in OC.

MicroRNA-21 induces loss of 15-hydroxyprostaglandin dehydrogenase in early gastric tubular adenocarcinoma

15-hydroxyprostaglandin dehydrogenase (15-PGDH), the rate-limiting enzyme in prostaglandin E2 degradation, is decreased in gastric cancers and microRNA (miR)-21 is one of the regulators. We investigated the expression and regulation of 15-PGDH in eary gastric carcinogenesis utilizing endoscopic submucosal dissection (ESD) and gastric cancer cell lines. Expression of 15-PGDH and cyclooxygenase-2 as well as the promoter methylation of 15-PGDH were evaluted. CRISPR, miR-21 transfection, proliferation and apoptosis assays were also done. We observed significant decreases in 15-PGDH expression but no promoter methylation was detected in any ESDs. 15-PGDH suppression by CRISPR induced enhanced growth kinetics. miR-21, which was detected in high level in gastric tumors from the TGCA data, caused increased proliferation, decreased apoptosis. miR-21 overexpression was confirmed with CISH and RT-PCR in the ESDs. Loss of 15-PGDH occurs at the very early stage of gastric adenocarcinoma by miR-21. H. pylori infection may affect miR-21 up regulation. Maintaining 15-PGDH enzyme activity could be a new strategic measure in preventing gastric cancer especially tubular adenocarcinoma.

Quinacrine upregulates p21/p27 independent of p53 through autophagy-mediated downregulation of p62-Skp2 axis in ovarian cancer

We have previously shown that the anti-malarial compound Quinacrine (QC) inhibits ovarian cancer (OC) growth by modulating autophagy. In the present study we extended these studies to identify the molecular pathways regulated by QC to promote apoptosis independent of p53 status in OC. QC exhibited strong anti-cancer properties in OC cell lines in contrast to other anti-malarial autophagy inhibiting drugs. QC treatment selectively upregulated cell cycle inhibitor p21, and downregulated F box protein Skp2 and p62/SQSTM1 expression independent of p53 status. Genetic downregulation of key autophagy protein ATG5 abolished QC-mediated effects on both cell cycle protein p21/Skp2 as well as autophagic cargo protein p62. Furthermore, genetic silencing of p62/SQSTM1 resulted in increased sensitivity to QC-mediated apoptosis, downregulated Skp2 mRNA and increased accumulation of p21 expression. Likewise, genetic knockdown of Skp2 resulted in the upregulation of p21 and p27 and increased sensitivity of OC cells to QC treatment. In contrast, transient overexpression of exogenous p62-HA plasmid rescued the QC-mediated Skp2 downregulation indicating the positive regulation of Skp2 by p62. Collectively, these data indicate that QC-mediated effects on cell cycle proteins p21/Skp2is autophagy-dependent and p53-independent in high grade serious OC cells.

CNOT2 promotes proliferation and angiogenesis via VEGF signaling in MDA-MB-231 breast cancer cells

Here the underlying role of CNOT2, a subunit of CCR4-NOT complex, was elucidated in cancer progression. CNOT2 was overexpressed in HIT-T15, ASPC-1, BXPC-3, PC-3, LNCaP, MCF-7 and MDA-MB-231 cell lines, which was confirmed by Tissue array in various human tumor tissues. Also, CNOT2 depletion suppressed proliferation and colony formation of MDA-MB-231 cells. Of note, microarray revealed decreased expression of CNOT2, VEGF-A, HIF2 alpha (<0.5 fold) and increased expression of UMOD1, LOC727847, MMP4, hCG and other genes (>2.0 fold) in CNOT2 depleted MDA-MB-231 cells compared to untreated control. Consistently, downregulation of VEGF, CNOT2 and HIF2 alpha was verified in CNOT2 depleted MDA-MB-231 cells by RT-qPCR. Additionally, CNOT2 depletion inhibited VEGF induced tube formation in HUVECs and reduced neovascularization in CAM assay. Furthermore, the growth of CNOT2 depleted MDA-MB-231 cells was significantly reduced in Balb/c nude mice along with decreased expression of VEGF and PCNA by immunohistochemistry compared to untreated control group. Overall, our findings provide evidences that CNOT2 promotes proliferation and angiogenesis via VEGF signaling in MDA-MB-231 breast cancer cells as a potent molecular target for breast cancer treatment.

Loss of HSulf-1: The Missing Link between Autophagy and Lipid Droplets in Ovarian Cancer

Defective autophagy and deranged metabolic pathways are common in cancer; pharmacologic targeting of these two pathways could provide a viable therapeutic option. However, how these pathways are regulated by limited availability of growth factors is still unknown. Our study shows that HSulf-1 (endosulfatase), a known tumor suppressor which attenuates heparin sulfate binding growth factor signaling, also regulates interplay between autophagy and lipogenesis. Silencing of HSulf-1 in OV202 and TOV2223 cells (ovarian cancer cell lines) resulted in increased lipid droplets (LDs), reduced autophagic vacuoles (AVs) and less LC3B puncta. In contrast, HSulf-1 proficient cells exhibit more AVs and reduced LDs. Increased LDs in HSulf-1 depleted cells was associated with increased ERK mediated cPLA2^S505 phosphorylation. Conversely, HSulf-1 expression in SKOV3 cells reduced the number of LDs and increased the number of AVs compared to vector controls. Furthermore, pharmacological (AACOCF3) and ShRNA mediated downregulation of cPLA2 resulted in reduced LDs, and increased autophagy. Finally, in vivo experiment using OV202 Sh1 derived xenograft show that AACOCF3 treatment effectively attenuated tumor growth and LD biogenesis. Collectively, these results show a reciprocal regulation of autophagy and lipid biogenesis by HSulf-1 in ovarian cancer.

Decursin enhances TRAIL-induced apoptosis through oxidative stress mediated- endoplasmic reticulum stress signalling in non-small cell lung cancers

BACKGROUND AND PURPOSE

The TNF-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent due to its remarkable ability to selectively kill tumour cells. However, because most tumours exhibit resistance to TRAIL-induced apoptosis, the development of combination therapies to overcome resistance to TRAIL is required for effective cancer therapy.

EXPERIMENTAL APPROACH

Cell viability and possible synergy between the plant pyranocoumarin decursin and TRAIL was measured by MTT assay and calcusyn software. Reactive oxygen species (ROS) and apoptosis were measured using dichlorodihydrofluorescein and annexin/propidium iodide in cell flow cytometry. Changes in protein levels were assessed with Western blotting.

KEY RESULTS

Combining decursin and TRAIL markedly decreased cell viability and increased apoptosis in TRAIL-resistant non-small-cell lung cancer (NSCLC) cell lines. Decursin induced expression of the death receptor 5 (DR5). Inhibition of DR5 attenuated apoptotic cell death in decursin + TRAIL treated NSCLC cell lines. Interestingly, induction of DR5 and CCAAT/enhancer-binding protein homologues protein by decursin was mediated through selective induction of the pancreatic endoplasmic reticulum kinase (PERK)/activating transcription factor 4 (ATF4) branch of the endoplasmic reticulum stress response pathway. Furthermore, enhancement of PERK/ATF4 signalling by decursin was mediated by ROS generation in NSCLC cell lines, but not in normal human lung cells. Decursin also markedly down-regulated expression of survivin and Bcl-xL in TRAIL-resistant NSCLC cells.

CONCLUSIONS AND IMPLICATIONS

ROS generation by decursin selectively activated the PERK/ATF4 axis of the endoplasmic reticulum stress signalling pathway, leading to enhanced TRAIL sensitivity in TRAIL-resistant NSCLC cell lines, partly via up-regulation of DR5.

CCR4-NOT2 Promotes the Differentiation and Lipogenesis of 3T3-L1 Adipocytes via Upregulation of PPARx03B3;, CEBPα and Inhibition of P-GSK3α/β and β-Catenin

BACKGROUND/AIMS

Though CCR4-NOT2 (CNOT2), one of CCR4-NOT complex subunits, was known to be involved in metastasis and apoptosis through transcription and mRNA degradation, its other biological function is poorly understood so far. The aim of this study is to elucidate the molecular role of CNOT2 in the differentiation process of 3T3-L1 preadipocytes.

METHODS AND RESULTS

CNOT2 was overexpressed during the differentiation process of 3T3-L1 preadipocytes. Consistently, mRNA levels of CNOT2, adiponectin, adiponectin 2, PPARx03B3; and CEBPα were enhanced in 3T3-L1 adipocytes. Conversely, CNOT2 depletion by siRNA transfection also reversed the activation of PPARx03B3; and CEBPα and inhibition of GSK3α/β and β-catenin at the protein level in 3T3-L1 preadipocytes. Immunofluorescence assay revealed that CNOT2 was colocalized with PPARx03B3;, but not with CEBPα in 3T3-L1 adipocyte. Consistently, IP western blots revealed that CNOT2 interacted with PPARx03B3; in 3T3-L1 adipocyte.

CONCLUSION

Our findings demonstrate that CNOT2 promotes the differentiation of 3T3-L1 preadipocytes via upregulation of PPARx03B3;, and CEBPα and inhibition of GSK3α/β and β-catenin signaling as a potent molecular target for obesity.

Apoptotic Effect of Sanggenol L via Caspase Activation and Inhibition of NF-κB Signaling in Ovarian Cancer Cells

In the present study, the underlying apoptotic mechanism of sanggenol L was elucidated in ovarian cancer cells. Sanggenol L showed cytotoxic and antiproliferative effect in A2780, SKOV-3, and OVCAR-3 ovarian cancer cells in a concentration-dependent fashion. Consistently, sanggenol L increased sub-G1 phase population and early and late apoptotic portion in ovarian cancer cells. Also, sanggenol L activated caspase9/3, suppressed the phosphorylation of IκBα and p65 NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), attenuated the expression of Cyclin D1, and cleaved poly(adenosine diphosphate ribose -ribose) polymerase in SKOV-3, A2780, and OVCAR-3 cells. Furthermore, sanggenol L blocked nuclear translocation of NF-κB and also attenuated the expression of NF-κB related genes such as c-Myc, Cyclin D1, and Bcl-X L, Bcl-2, in lipopolysaccharide-treated SKOV-3 cells. Overall, our findings for the first time suggest that sanggenol L induces apoptosis via caspase activation and inhibition of NF-κB/IκBα phosphorylation as a potent chemotherapeutic agent for ovarian cancers.

Abstract 26: Suppression of E-cadherin mediates gallotannin-induced apoptosis in Hep G2 hepatocelluar carcinoma cells

Though gallotannin was known to have anti-oxidant and antitumor activity, the underlying antitumor mechanism of gallotannin still remains unclear. Thus, in the present study, antitumor mechanism of gallotannin was elucidated in hepatocellular carcinoma cells. Gallotannin significantly exerted cytotoxicity against Hep G2 and Chang hepatocellular carcinoma cells with the accumulation of the sub-G1 population and increase of terminal deoxynucleotidyltransferasedUTP nick end labeling (TUNEL) positive cells as an apoptotic feature. Also, gallotannin attenuated the expression of pro-caspase9, pro-caspase3, Bcl2 and integrin β1 and cleaved poly(ADP)-ribose polymerase (PARP) in Hep G2 and Chang cancer cells. Furthermore, gallotannin suppressed cell repair motility by wound healing assay and also inhibited cell adhesion in Hep G2 cells. Of note, gallotannin attenuated the expression of epithelial cadherin (E-cadherin) to form cell-cell adhesion from the early stage, and also beta-catenin at late phase in Hep G2 cells. Consistently, Immunofluorescence assay showed that E-cadherin or β-catenin expression was suppressed in a time dependent manner by gallotannin. Furthermore, silencing of E-cadherin by siRNA transfection method enhanced PAPR cleavage, caspase 3 activation and sub G1 population and attenuated the cell adhesion induced by gallotannin in Hep G2 cells. Overall, our findings demonstrate that the disruption of cell adhesion junction by suppression of E-cadherin mediates gallotannin enhanced apoptosis in Hep G2 liver cancer cells.

Citation Format: Hee Young Kwon, Ji Hoon Jung, Hyun Joo Lee, Myoung Seok Jeong, Deok-Beom Jung, Bonglee Kim, Hyemin Lee, Sung-Hoon Kim. Suppression of E-cadherin mediates gallotannin-induced apoptosis in Hep G2 hepatocelluar carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 26. doi:10.1158/1538-7445.AM2015-26

A derivative of epigallocatechin-3-gallate induces apoptosis via SHP-1-mediated suppression of BCR-ABL and STAT3 signalling in chronic myelogenous leukaemia

BACKGROUND AND PURPOSE

Epigallocatechin-3-gallate (EGCG) is a component of green tea known to have chemo-preventative effects on several cancers. However, EGCG has limited clinical application, which necessitates the development of a more effective EGCG prodrug as an anticancer agent.

EXPERIMENTAL APPROACH

Derivatives of EGCG were evaluated for their stability and anti-tumour activity in human chronic myeloid leukaemia (CML) K562 and KBM5 cells.

KEY RESULTS

EGCG-mono-palmitate (EGCG-MP) showed most prolonged stability compared with other EGCG derivatives. EGCG-MP exerted greater cytotoxicity and apoptosis in K562 and KBM5 cells than the other EGCG derivatives. EGCG-MP induced Src-homology 2 domain-containing tyrosine phosphatase 1 (SHP-1) leading decreased oncogenic protein BCR-ABL and STAT3 phosphorylation in CML cells, compared with treatment with EGCG. Furthermore, EGCG-MP reduced phosphorylation of STAT3 and survival genes in K562 cells, compared with EGCG. Conversely, depletion of SHP-1 or application of the tyrosine phosphatase inhibitor pervanadate blocked the ability of EGCG-MP to suppress phosphorylation of BCR-ABL and STAT3, and the expression of survival genes downstream of STAT3. In addition, EGCG-MP treatment more effectively suppressed tumour growth in BALB/c athymic nude mice compared with untreated controls or EGCG treatment. Immunohistochemistry revealed increased caspase 3 and SHP-1 activity and decreased phosphorylation of BCR-ABL in the EGCG-MP-treated group relative to that in the EGCG-treated group.

CONCLUSIONS AND IMPLICATIONS

EGCG-MP induced SHP-1-mediated inhibition of BCR-ABL and STAT3 signalling in vitro and in vivo more effectively than EGCG. This derivative may be a potent chemotherapeutic agent for CML treatment.

Activation of Caspase-9/3 and Inhibition of Epithelial Mesenchymal Transition are Critically Involved in Antitumor Effect of Phytol in Hepatocellular Carcinoma Cells

This study was designed to investigate the antitumor mechanism of Phytol in hepatocellular carcinomas including Huh7 and HepG2 cells in association with caspase dependent apoptosis and epithelial mesenchymal transition (EMT) signaling. Phytol significantly suppressed the viability of Huh7 and HepG2 cells. Also, Phytol significantly increased the sub G1 population and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) positive cells in a concentration dependent manner in Huh7 and HepG2 cells. Consistently, Phytol cleaved poly (adenosine diphosphate-ribose) polymerase (PARP), activated caspase-9/3, and Bax attenuated the expression of survival genes such as Bcl-2, Mcl-1, and c-Myc in Huh7 and HepG2 cells. Of note, Phytol also suppressed typical morphology change of EMT such as loss of cell adhesion and formation of fibroblast like mesenchymal cells in HepG2 cells. Furthermore, Phytol also reversed the loss of E-cadherin and overexpression of p-smad2/3, alpha-smooth muscle actin, and Snail induced by EMT promoter transforming growth factor beta1 in HepG2 cells. Overall, our findings suggest that Phytol exerts antitumor activity via apoptosis induction through activation of caspas-9/3 and inhibition of EMT in hepatocellular carcinoma cells as a potent anticancer candidate for liver cancer treatment.

Apoptotic Effect of Galbanic Acid via Activation of Caspases and Inhibition of Mcl-1 in H460 Non-Small Lung Carcinoma Cells

Galbanic acid (GBA), a major compound of Ferula assafoetida, was known to have cytotoxic, anti-angiogenic and apoptotic effects in prostate cancer and murine Lewis lung cancer cells; the underling apoptotic mechanism of GBA still remains unclear so far. Thus, in the present study, the apoptotic mechanism of GBA was investigated mainly in H460 non-small cell lung carcinoma (NSCLC) cells because H460 cells were most susceptible to GBA than A549, PC-9 and HCC827 NSCLC cells. Galbanic acid showed cytotoxicity in wild EGFR type H460 and A549 cells better than other mutant type PC-9 and HCC827 NSCLC cells. Also, GBA significantly increased the number of Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells and sub G1 population in H460 cells. Western blotting revealed that GBA cleaved poly (ADP-ribose) polymerase (PARP), activated Bax and caspase 9, attenuated the expression of Bcl-2, Bcl-x(L), and Myeloid cell leukemia 1 (Mcl-1) in H460 cells. However, interestingly, overexpression of Mcl-1 blocked the ability of GBA to exert cytotoxicity, activate caspase9 and Bax, cleave PARP, and increase sub G1 accumulation in H460 cells. Overall, these findings suggest that GBA induces apoptosis in H460 cells via caspase activation and Mcl-1 inhibition in H460 cells as a potent anticancer agent for NSCLC treatment.

Abstract 2439: HSulf-1 loss in ovarian cancer cells induces lipid droplet biogenesis

We have previously shown that a frequent loss of endosulfatase HSulf-1 in ovarian cancer enhances the heparin binding growth factor signaling which subsequently induces and potentiates tumorigenesis. Our recent data indicate that knockdown of HSulf-1 in ovarian cancer cells significantly alter levels of several metabolites which is comparable to the deranged metabolite profiles in primary ovarian tumors. Here we report that the metabolites associated with lipid metabolism are altered in such a way that the cells start manifesting a “lipogenic phenotype” characterized by an increased fatty acid synthesis, storage and mitochondrial beta oxidation. The lipogenic phenotype is associated with an accumulation of cytoplasmic lipid droplets (LDs) in a stably HSulf-1 knockdown cells [OV202 (Sh1/2) and OV2223 cells]. Presence of LDs is evidenced by BODIPY staining and transmission electron microscopy (TEM) analysis in Sh1/2 and a non-transduced control (NTC) cells. Conversely, enhanced expression of HSulf-1 in TOV21G, SKOV3, and C13 cells also resulted in reducing the number of LDs. More importantly, MEFs (mouse embryonic fibroblasts) from HSulf-1 knockout mice also showed an increased LD biogenesis compared to the wild type MEFs. Microarray analysis identified cytoplasmic phospholipase A2 (cPLA2; an enzyme involved in LD biogenesis) as one of the genes that was significantly upregulated in OV202 Sh1 and Sh2 cells. We found that Sh1 and Sh2 cells show an increased phosphorylation (ser505) of cytoplasmic phospholipase A2 (p-cPLA2) compared to NTC cells. Phosphorylation at ser505 is vital for the enzyme activity of cPLA2 and also necessary for LD biogenesis. We inhibited the LD biogenesis in Sh1 cells by a pharmacological inhibitor of cPLA2 (AACOCF3 and MAFP) as well by shRNA mediated knockdown of endogenous cPLA2. Further, we stimulated NTC and Sh1 cells with heparin binding growth factor (50ng/ml) for different time points and found an elevated phosphorylation of cPLA2 and extracellular signal related kinase (ERK), which is also inhibited by a pre-treatment of cells with cPLA2 inhibitor. Interestingly, inhibition of phospho-ERK by U0126 (MEK inhibitor) also inhibits the phosphorylation of cPLA2. These findings strongly suggest that loss of HSulf-1 promotes lipid metabolism in the ovarian cancer cells via activation of cPLA2 via an ERK dependent pathway. The present work highlights a novel role HSulf-1 in regulating lipid metabolism which could lead to a better understanding of tumorigenesis and identification of new targets for tumor therapy.

Citation Format: Debarshi Roy, Xiaoping He, Ashwani Khurana, Susmita Mondal, Deok-Beom Jung, Sung Kim, Thomas Dierks, Clifford Folmes, Andre Terzic, Viji Shridhar. HSulf-1 loss in ovarian cancer cells induces lipid droplet biogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2439. doi:10.1158/1538-7445.AM2014-2439

Loss of HSulf-1 promotes altered lipid metabolism in ovarian cancer

Background

Loss of the endosulfatase HSulf-1 is common in ovarian cancer, upregulates heparin binding growth factor signaling and potentiates tumorigenesis and angiogenesis. However, metabolic differences between isogenic cells with and without HSulf-1 have not been characterized upon HSulf-1 suppression in vitro. Since growth factor signaling is closely tied to metabolic alterations, we determined the extent to which HSulf-1 loss affects cancer cell metabolism.

Results

Ingenuity pathway analysis of gene expression in HSulf-1 shRNA-silenced cells (Sh1 and Sh2 cells) compared to non-targeted control shRNA cells (NTC cells) and subsequent Kyoto Encyclopedia of Genes and Genomics (KEGG) database analysis showed altered metabolic pathways with changes in the lipid metabolism as one of the major pathways altered inSh1 and 2 cells. Untargeted global metabolomic profiling in these isogenic cell lines identified approximately 338 metabolites using GC/MS and LC/MS/MS platforms. Knockdown of HSulf-1 in OV202 cells induced significant changes in 156 metabolites associated with several metabolic pathways including amino acid, lipids, and nucleotides. Loss of HSulf-1 promoted overall fatty acid synthesis leading to enhance the metabolite levels of long chain, branched, and essential fatty acids along with sphingolipids. Furthermore, HSulf-1 loss induced the expression of lipogenic genes including FASN, SREBF1, PPARγ, and PLA2G3 stimulated lipid droplet accumulation. Conversely, re-expression of HSulf-1 in Sh1 cells reduced the lipid droplet formation. Additionally, HSulf-1 also enhanced CPT1A and fatty acid oxidation and augmented the protein expression of key lipolytic enzymes such as MAGL, DAGLA, HSL, and ASCL1. Overall, these findings suggest that loss of HSulf-1 by concomitantly enhancing fatty acid synthesis and oxidation confers a lipogenic phenotype leading to the metabolic alterations associated with the progression of ovarian cancer.

Conclusions

Taken together, these findings demonstrate that loss of HSulf-1 potentially contributes to the metabolic alterations associated with the progression of ovarian pathogenesis, specifically impacting the lipogenic phenotype of ovarian cancer cells that can be therapeutically targeted.

Reactive oxygen species-mediated activation of JNK and down-regulation of DAXX are critically involved in penta-O-galloyl-beta-d-glucose-induced apoptosis in chronic myeloid leukemia K562 cells

Although 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG) was well known to have antitumor activities in breast, prostate, kidney, liver cancers and HL-60 leukemia via regulation of caspase 3, p53, S-phase kinase-associated protein 2 (Skp2) and insulin receptor signaling, the underlying mechanism of PGG-induced apoptosis linked with reactive oxygen species (ROS) mediated c-Jun N-terminal kinase (JNK) and DAXX was never elucidated in chronic myeloid leukemia (CML) K562 cells until now. Herein PGG significantly decreased the viability of CML cell lines such as K562 and KBM-5 without hurting normal peripheral blood lymphocytes (PBLs). PGG increased the number of TUNEL-positive cells and the sub-G1 cell population as well as activated caspase cascades including caspase-8, -9 and -3 in K562 cells. Interestingly, a significant activation of JNK by PGG was observed by MULTIPLEX assay and Western blotting. Conversely, JNK inhibitor D-JNKi suppressed the cleavages of caspase 3 and PARP induced by PGG in K562 cells. Also, PGG dramatically enhanced generation of ROS and reduced the expression of death-domain-associated protein (DAXX). Of note, ROS inhibitor acetyl-L-cysteine (NAC) reversed JNK-dependent apoptosis and DAXX inhibition induced by PGG. Overall, these findings suggest that ROS-dependent JNK activation and DAXX downregulation are critically involved in PGG-induced apoptosis in K562 cells.

Rhapontigenin inhibited hypoxia inducible factor 1 alpha accumulation and angiogenesis in hypoxic PC-3 prostate cancer cells

Hypoxia inducible factor 1 alpha (HIF-1α) is frequently over-expressed in the numerous types of cancer and plays an important role in angiogenesis. In the present study, the inhibitory mechanism of rhapontigenin isolated from Vitis coignetiae was investigated on HIF-1α stability and angiogenesis in human prostate cancer PC-3 cells. Rhapontigenin significantly suppressed HIF-1α accumulation at protein level but not at mRNA level in PC-3 cells under hypoxia. Also, rhapontigenin suppressed hypoxia-induced HIF-1α activation in various cancer cells, such as colorectal adenocarcinoma (SW620), breast adenocarcinoma (MCF-7), fibrosarcoma (HT-1080) and prostate carcinoma (LNCaP). Interestingly, rhapontigenin had more potency in inhibition of hypoxia-induced HIF-1α expression than that of resveratrol, a known HIF-1α inhibitor. In addition, rhapontigenin promoted hypoxia-induced HIF-1α degradation and cycloheximide (CHX) blocked protein synthesis. A prolyl hydroxylase (PHD) inhibitor dimethyloxalylglycine (DMOG) is usually utilized to examine whether prolyl hydroxylation is involved in inhibition of HIF-1α accumulation. Here, DMOG recovered HIF-1α accumulation inhibited by rhapontigenin. Immunoprecipitation assay also revealed that rhapotigenin enhanced the binding of hydroxylated HIF-1α to von Hippel-Lindau (VHL) tumor suppressor protein. Furthermore, rhapontigenin reduced vascular endothelial growth factor (VEGF) secretion in hypoxic PC-3 cells as well as suppressed tube formation in human umbilical vein endothelial cells (HUVECs) treated by the conditioned media of hypoxic PC-3 cells. However, anti-angiogenic effect of rhapontigenin in hypoxic PC-3 cells was reversed by DMOG. Taken together, these findings suggest that rhapontigenin inhibits HIF-1α accumulation and angiogenesis in PC-3 prostate cancer cells.

Tanshinone IIA induces mitochondria dependent apoptosis in prostate cancer cells in association with an inhibition of phosphoinositide 3-kinase/AKT pathway

Tanshinone IIA (Tan IIA; 14,16-epoxy-20-nor-5(10),6,8,13,15-abietapentaene-11,12-dione), a phytochemical derived from the roots of Salvia miltiorrhiza BUNGE, has been reported to posses anti-angiogenic, anti-oxidant, anti-inflammatory and apoptotic activities. However, the cancer growth inhibitory/cytocidal effects and molecular mechanisms in prostate cancer cells have not been well studied. In the present study, we demonstrate that Tan IIA significantly decreased the viable cell number of LNCaP (phosphate and tensin homolog (PTEN) mutant, high AKT, wild type p53) prostate cancer cells more sensitively than against the PC-3 (PTEN null, high AKT, p53 null) prostate cancer cells. Tan IIA significantly increased TdT-mediated dUTP nick-end labeling (TUNEL) positive index and sub-G1 DNA contents of treated cells, consistent with apoptosis. Tan IIA treatment led to cleavage activation of pro-caspases-9 and 3, but not pro-caspase-8, and cleavage of poly (ADP ribose) polymerase (PARP), a caspase-3 substrate. Additionally, Tan IIA treatment induced cytochrome c release from the mitochondria into the cytosol and reduced mitochondrial membrane potential and suppressed the expression of mitochondria protective Bcl-2 family protein Mcl-1(L). Tan IIA reduced the expression of phosphoinositide 3-kinase (PI3K) p85 subunit, and the phosphorylation of AKT and mammalian target of rapamycin (mTOR) in a concentration-dependent manner. Moreover, the combination of Tan IIA and LY294002, a specific PI3K inhibitor, enhanced PARP cleavage of LNCaP and PC-3, but not in MDA-MB-231 breast cancer cells which do not contain detectable active AKT. The findings suggest that Tan IIA-induced apoptosis involves mitochondria intrinsic caspase activation cascade and an inhibition of the PI3K/AKT survival pathway.

Suppression of STAT3 and HIF-1 alpha mediates anti-angiogenic activity of betulinic acid in hypoxic PC-3 prostate cancer cells

BACKGROUND

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. In the present study, we examined that betulinic acid (BA), a triterpene from the bark of white birch, had the inhibitory effects on hypoxia-mediated activation of STAT3 in androgen independent human prostate cancer PC-3 cells.

METHODOLOGY/PRINCIPAL FINDINGS

BA inhibited the protein expression and the transcriptional activities of hypoxia-inducible factor-1α (HIF-1α) under hypoxic condition. Consistently, BA blocked hypoxia-induced phosphorylation, DNA binding activity and nuclear accumulation of STAT3. In addition, BA significantly reduced cellular and secreted levels of vascular endothelial growth factor (VEGF), a critical angiogenic factor and a target gene of STAT3 induced under hypoxia. Furthermore, BA prevented in vitro capillary tube formation in human umbilical vein endothelial cells (HUVECs) maintained in conditioned medium of hypoxic PC-3 cells, implying anti-angiogenic activity of BA under hypoxic condition. Of note, chromatin immunoprecipitation (ChiP) assay revealed that BA inhibited binding of HIF-1α and STAT3 to VEGF promoter. Furthermore, silencing STAT3 using siRNA transfection effectively enhanced the reduced VEGF production induced by BA treatment under hypoxia.

CONCLUSIONS/SIGNIFICANCE

Taken together, our results suggest that BA has anti-angiogenic activity by disturbing the binding of HIF-1α and STAT3 to the VEGF promoter in hypoxic PC-3 cells.

Oral administration of penta-O-galloyl-β-D-glucose suppresses triple-negative breast cancer xenograft growth and metastasis in strong association with JAK1-STAT3 inhibition

There is an urgent clinical need for chemotherapeutic and chemopreventive drugs for triple-negative breast cancer (TNBCa). Extending on our recent work, we hypothesize that the herbal compound 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) can inhibit the growth and metastasis of TNBCa xenograft and target Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) 3-signaling axis. Daily oral gavage of 10 mg PGG/kg body wt decreased MDA-MB-231 xenograft weight by 49.3% (P < 0.01) at 40 days postinoculation, whereas weekly intraperitoneal injections of Taxol at the same dosage resulted in a 21.4% reduction (P > 0.1). PGG treatment also decreased the incidence of lung metastasis. Immunohistochemical staining detected decreased Ki-67 (proliferation) index and increased terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (apoptosis) index in PGG-treated and Taxol-treated xenografts. However, the CD34 (angiogenesis) index was decreased only in PGG-treated xenografts along with decreased phospho-STAT3. In cell culture of MDA-MB-231 cells, PGG decreased pSTAT3 and its downstream target proteins, decreased its upstream kinase pJAK1 and induced the expression of SHP1, a JAK1 upstream tyrosine phosphatase, within as early as 1 h of exposure. The phosphatase inhibitor pervanadate reversed the PGG-induced downregulation of pSTAT3 and caspase activation. Orally administered PGG can inhibit TNBCa growth and metastasis, probably through anti-angiogenesis, antiproliferation and apoptosis induction. Mechanistically, PGG-induced inhibition of JAK1-STAT3 axis may contribute to the observed in vivo efficacy and the effects on the cellular processes.

Association of total tooth loss with socio-behavioural health indicators in Korean elderly

This study examined the association between total tooth loss, and socio-behavioural factors and general health indicators in elderly Koreans using national databases. Cross-sectional data for this study were from the third Korean National Health and Nutrition Examination Survey (KNHANES III), which was conducted among non-institutionalised civilians by the Korean Ministry of Health and Welfare in 2005. KNHANES III used a stratified, multistage probability sampling design on a representative of total South Korean population, according to geographical areas, age and sex groups. Among them, 1091 subjects aged 65 years and above were identified as potential participants in this study. The dependent variable in this study was the self-reported total tooth loss. The independent variables consisted of the following four categories: demographic information, socio-behavioural factors, psychological factors and general health indicators. The data were weighted to adjust for the sampling complexity, and SPSS version 14 for Windows software was used for data analysis. There were significant differences in total tooth loss odds according to the socio-behavioural backgrounds (education and smoking), psychological conditions (perceived oral health) and general health status (diabetes and body mass index as underweight). This suggests that the total tooth loss is associated with the socio-economic status, health-related behaviour and general health. However, more extensive longitudinal data and research will be needed to better explain the relationship between the total tooth loss and these variables.