CD109 Promotes Drug Resistance in A2780 Ovarian Cancer Cells by Regulating the STAT3-NOTCH1 Signaling Axis.

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy owing to relapse caused by resistance to chemotherapy. We previously reported that cluster of differentiation 109 (CD109) expression is positively correlated with poor prognosis and chemoresistance in patients with EOC. To further explore the role of CD109 in EOC, we explored the signaling mechanism of CD109-induced drug resistance. We found that CD109 expression was upregulated in doxorubicin-resistant EOC cells (A2780-R) compared with that in their parental cells. In EOC cells (A2780 and A2780-R), the expression level of CD109 was positively correlated with the expression level of ATP-binding cassette (ABC) transporters, such as ABCB1 and ABCG2, and paclitaxel (PTX) resistance. Using a xenograft mouse model, it was confirmed that PTX administration in xenografts of CD109-silenced A2780-R cells significantly attenuated in vivo tumor growth. The treatment of CD109-overexpressed A2780 cells with cryptotanshinone (CPT), a signal transducer and activator of transcription 3 (STAT3) inhibitor, inhibited the CD109 overexpression-induced activation of STAT3 and neurogenic locus notch homolog protein 1 (NOTCH1), suggesting a STAT3-NOTCH1 signaling axis. The combined treatment of CD109-overexpressed A2780 cells with CPT and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), a NOTCH inhibitor, markedly abrogated PTX resistance. These results suggest that CD109 plays a key role in the acquisition of drug resistance by activating the STAT3-NOTCH1 signaling axis in patients with EOC.

TRRAP Enhances Cancer Stem Cell Characteristics by Regulating NANOG Protein Stability in Colon Cancer Cells.

NANOG, a stemness-associated transcription factor, is highly expressed in many cancers and plays a critical role in regulating tumorigenicity. Transformation/transcription domain-associated protein (TRRAP) has been reported to stimulate the tumorigenic potential of cancer cells and induce the gene transcription of NANOG. This study aimed to investigate the role of the TRRAP-NANOG signaling pathway in the tumorigenicity of cancer stem cells. We found that TRRAP overexpression specifically increases NANOG protein stability by interfering with NANOG ubiquitination mediated by FBXW8, an E3 ubiquitin ligase. Mapping of NANOG-binding sites using deletion mutants of TRRAP revealed that a domain of TRRAP (amino acids 1898-2400) is responsible for binding to NANOG and that the overexpression of this TRRAP domain abrogated the FBXW8-mediated ubiquitination of NANOG. TRRAP knockdown decreased the expression of CD44, a cancer stem cell marker, and increased the expression of P53, a tumor suppressor gene, in HCT-15 colon cancer cells. TRRAP depletion attenuated spheroid-forming ability and cisplatin resistance in HCT-15 cells, which could be rescued by NANOG overexpression. Furthermore, TRRAP knockdown significantly reduced tumor growth in a murine xenograft transplantation model, which could be reversed by NANOG overexpression. Together, these results suggest that TRRAP plays a pivotal role in the regulation of the tumorigenic potential of colon cancer cells by modulating NANOG protein stability.

Role of autotaxin in cancer stem cells.

Stem cells are a rare subpopulation defined by the potential to self-renew and differentiate into specific cell types. A population of stem-like cells has been reported to possess the ability of self-renewal, invasion, metastasis, and engraftment of distant tissues. This unique cell subpopulation has been designated as cancer stem cells (CSC). CSC were first identified in leukemia, and the contributions of CSC to cancer progression have been reported in many different types of cancers. The cancer stem cell hypothesis attempts to explain tumor cell heterogeneity based on the existence of stem cell-like cells within solid tumors. The elimination of CSC is challenging for most human cancer types due to their heightened genetic instability and increased drug resistance. To combat these inherent abilities of CSC, multi-pronged strategies aimed at multiple aspects of CSC biology are increasingly being recognized as essential for a cure. One of the most challenging aspects of cancer biology is overcoming the chemotherapeutic resistance in CSC. Here, we provide an overview of autotaxin (ATX), lysophosphatidic acid (LPA), and their signaling pathways in CSC. Increasing evidence supports the role of ATX and LPA in cancer progression, metastasis, and therapeutic resistance. Several studies have demonstrated the ATX-LPA axis signaling in different cancers. This lipid mediator regulatory system is a novel potential therapeutic target in CSC. In this review, we summarize the evidence linking ATX-LPA signaling to CSC and its impact on cancer progression and metastasis. We also provide evidence for the efficacy of cancer therapy involving the pharmacological inhibition of this signaling pathway.

Risk factors related to the recurrence of endometrioma in patients with long-term postoperative medical therapy.

OBJECTIVES: The purpose of this study was to identify clinical risk factors for the recurrence of ovarian endometrioma after ovarian cystectomy in Korean women with long-term postoperative medical therapy. MATERIAL AND METHODS: A total of 134 patients who were surgically treated for endometriotic cysts at Pusan National University Hospital were included in this retrospective study. All patients received long-term postoperative medical treatment for at least 12 months after the first-line conservative surgery. Several epidemiologic variables were analyzed as possible risk factors for recurrence. Endometrioma recurrence was considered when a cystic mass was observed on transvaginal or transrectal sonography. Statistical analysis was performed using independent t-tests for parametric continuous variables. RESULTS: The mean follow-up period for the 134 patients was 56.5 ± 14.3 months (range, 36-120 months) and the mean duration of the medical therapy was 17.9 ± 17.3 months (range, 12-120 months). The overall recurrence rate was 35/134 (26.12%). Our univariate analysis showed statistically significant differences between the recurrent and non-recurrent groups in terms of weight (P = 0.013), body mass index (P = 0.007), age at the time of surgery (P = 0.013), the diameter of the largest cyst (P = 0.001), the presence of dysmenorrhea (P < 0.0001), and postoperative pregnancy (P = 0.016). Multivariate analysis showed that body mass index (OR 1.153, 95% CI 1.003-1.326, P = 0.046), age at the time of surgery (OR 0.924, 95% CI 0.860-0.992, P = 0.029), and presence of dysmenorrhea (OR 12.226, 95% CI 3.543-42.188, P < 0.0001) were significantly correlated with the recurrence of endometrioma. CONCLUSIONS: We found that patients with dysmenorrhea after surgery, and a younger age of the patient at the time of surgery were the highest risk factors associated with the recurrence of endometrioma, despite long-term postoperative medication.

Autotaxin Regulates Maintenance of Ovarian Cancer Stem Cells through Lysophosphatidic Acid-Mediated Autocrine Mechanism.

Ovarian cancer shows high mortality due to development of resistance to chemotherapy and relapse. Cancer stem cells (CSCs) have been suggested to be a major contributor in developing drug resistance and relapse in ovarian cancer. In this study, we isolated CSCs through sphere culture of A2780, SKOV3, OVCAR3 epithelial ovarian cancer cells and primary ovarian cancer cells from patients. We identified heat-stable factors secreted from ovarian CSCs stimulated migration and proliferation of CSCs. Mass spectrometry and ELISA analysis revealed that lysophosphatidic acid (LPA) was significantly elevated in CSC culture media compared with non-CSC culture media. Treatment of CSCs with LPA resulted in augmented CSC characteristics such as sphere-forming ability, resistance to anticancer drugs, tumorigenic potential in xenograft transplantation, and high expression of CSC-associated genes, including OCT4, SOX2, and aldehyde dehydrogenase 1. Treatment of CSCs with LPA receptor 1-specific inhibitors or silencing of LPA receptor 1 expression abrogated the LPA-stimulated CSC properties. Autotaxin, an LPA-producing enzyme, is highly secreted from ovarian CSCs, and pharmacological inhibition or knockdown of autotaxin markedly attenuated the LPA-producing, tumorigenic, and drug resistance potentials of CSCs. Clinicopathological analysis showed a significant survival disadvantage of patients with positive staining of autotaxin. In addition, we further identified that AKT1 activity was upregulated in ovarian CSCs through an LPA-dependent mechanism and silencing of AKT1 expression led to suppression of CSC characteristics. These results suggest that autotaxin-LPA-LPA receptor 1-AKT1 signaling axis is critical for maintaining CSC characteristics through an autocrine loop and provide a novel therapeutic target for ovarian CSCs.

BBT-877, a Novel Autotaxin Inhibitor, Abrogates Drug Resistance in Epithelial Ovarian Cancer Stem Cells.

BACKGROUND/AIM: Cancer stem cells (CSCs) contribute significantly to the poor prognosis of patients with epithelial ovarian cancer (EOC) due to their roles in drug resistance and tumor metastasis. Autotaxin (ATX) plays a pivotal role in the maintenance of the CSC-like properties of EOC tumors. BBT-877 is a novel ATX inhibitor used in clinical treatment of idiopathic pulmonary fibrosis. However, the effects of BBT-877 on drug resistance and metastasis in ovarian CSCs remain unknown. In this study, we aimed to investigate the effects of BBT-877 on drug resistance and intraperitoneal metastasis of EOC. MATERIALS AND METHODS: Spheroid-forming CSCs, which were isolated from two EOC cell lines, A2780 and SKOV3, were investigated by cell viability, western blot, PCR, Spheroid-forming assay, and in vivo experiments. RESULTS: Spheroid-forming CSCs exhibited increased CSC-like properties and paclitaxel (PTX) resistance. BBT-877 treatment inhibited the viability of spheroid-forming CSCs more potently than that of adherent ovarian cancer cell lines. Combinatorial treatment with BBT-877 and PTX significantly attenuated the viability of spheroid-forming CSCs. In a SKOV3 cells-derived intraperitoneal metastasis model, BBT-877 treatment reduced the number of metastatic tumor nodes, while combinatorial treatment with BBT-877 and PTX more potently attenuated the formation of metastatic nodes and accumulation of ascitic fluid. CONCLUSION: These results suggest that BBT-877 can be combined with conventional anticancer drugs for the treatment of patients with recurrent or drug-resistant EOC.

TAZ mediates lysophosphatidic acid-induced migration and proliferation of epithelial ovarian cancer cells.

BACKGROUND: Transcriptional co-activator with PDZ-binding motif (TAZ), a downstream effector of the Hippo pathway, has been reported to regulate organ size, tissue homeostasis, and tumorigenesis by acting as a transcriptional co-activator. Lysophosphatidic acid (LPA) is a bioactive lipid implicated in tumorigenesis and metastasis of ovarian cancer through activation of G protein-coupled receptors. However, the involvement of TAZ in LPA-induced tumorigenesis of ovarian cancer has not been elucidated. METHODS: In order to demonstrate the role of TAZ in LPA-stimulated tumorigenesis, the effects of LPA on TAZ expression and cell migration were determined by Western blotting and chemotaxis analyses in R182 human epithelial ovarian cancer cells. RESULTS AND CONCLUSION: Treatment of R182 cells with the LPA receptor inhibitor Ki16425 blocked LPA-induced cell migration. In addition, transfection of R182 cells with small interfering RNA specific for LPA receptor 1 resulted in abrogation of LPA-stimulated cell migration. LPA induced phosphorylation of ERK and p38 MAP kinase in R182 cells and pretreatment of cells with the MEK-ERK pathway inhibitor U0126, but not the p38 MAPK inhibitor SB202190, resulted in abrogation of LPA-induced cell migration. Pretreatment of R182 cells with U0126 attenuated LPA-induced mRNA levels of TAZ and its transcriptional target genes, such as CTGF and CYR61, without affecting phosphorylation level of YAP. These results suggest that MEK-ERK pathway plays a key role in LPA-induced cell migration and mRNA expression of TAZ in R182 cells, without affecting stability of TAZ protein. In addition, small interfering RNA-mediated silencing of TAZ expression attenuated LPA-stimulated migration of R182 cells. These results suggest that TAZ plays a key role in LPA-stimulated migration of epithelial ovarian cancer cells.

Parenting stress and child behavior problems among clinic-referred youth: cross-cultural differences across the US and Korea.

Due to increased multiculturalism in the US and abroad, there is a need for increased understanding of the different ways in which parenting stress is related to child problems across cultures. In the present study, we investigated (a) differences in reported parenting stress and childhood problem behaviors across a Korean (n = 71) and US (n = 71) sample, as well as (b) differences in the ways in which parenting stress and childhood problems were related across Korean and US children based on mothers' reports. Results revealed that Korean mothers reported significantly higher parenting stress yet significantly lower childhood problem behaviors compared to US mothers. In addition, mother-based reports of child problems were significantly associated with parenting stress in the US sample, but not in the Korean sample. Clinical implications and culturally-relevant issues relevant to these findings are addressed, including a potential under-reporting bias of child problems among Asian parents.

Decreased expressions of vascular endothelial growth factor and visfatin in the placental bed of pregnancies complicated by preeclampsia.

AIM: The aim of the present study was to examine the expression of vascular endothelial growth factor (VEGF) and visfatin in the third trimester placental bed of pregnancies with and without preeclampsia (PE). MATERIAL AND METHODS: The study group consisted of placental bed biopsy tissues obtained from pregnancies with (n = 20) and without (n = 20) PE. The normotensive controls without PE were matched for gestational age at delivery with patients with PE. The expression of VEGF and visfatin in the placental bed tissues were evaluated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time polymerase chain reaction (PCR), immunohistochemistry and Western blot. RESULTS: There was no statistical difference between the PE group and the normotensive control group in age and body mass index (BMI). The expression of VEGF and visfatin was significantly decreased in the PE group compared with the normotensive control group (P < 0.05). CONCLUSION: This study showed decreased expressions of VEGF and visfatin in the third trimester placental bed of pregnancies with PE compared with the normotensive controls. This result suggests that decreased expression of these angiogenic factors in placental bed may be associated with the pathogenesis of PE.

Lysophosphatidic acid-induced expression of periostin in stromal cells: Prognoistic relevance of periostin expression in epithelial ovarian cancer.

Lysophosphatidic acid (LPA) is a bioactive lipid crucial for the initiation and progression of ovarian cancer. Identification of LPA-induced biomarkers is necessary for predicting prognosis of ovarian cancer patients. Here we report periostin, an extracellular matrix protein, as an LPA-induced protein in stromal cells and as a prognostic marker in patients with epithelial ovarian cancer (EOC). In human EOC tissues, periostin was mainly expressed in cancer-associated stromal fibroblasts, but not in cancer cells. The expression levels of periostin highly correlated with poor survival and tumor recurrence of ovarian cancer patients. Treatment of human adipose tissue-derived stromal cells with LPA or conditioned media from human ovarian adenocarcinoma cell lines, such as SK-OV-3 and OVCAR-3, induced expression of periostin. The periostin expression induced by cancer-conditioned media was abrogated by silencing of the LPA receptor 1 expression using small hairpin RNA lentivirus. Recombinant periostin stimulated adhesion and invasion of SK-OV-3 human ovarian adenocarcinoma cells and induced expression of matrix metalloprotease-2 in the cancer cells. These results suggest that LPA is associated with the expression of periostin in cancer-associated fibroblasts of EOC.

Inactivation of O6-methyguanine-DNA methyltransferase by promoter hypermethylation: association of epithelial ovarian carcinogenesis in specific histological types.

AIM: The aim of this study was to evaluate O6-methyguanine-DNA methyltransferase (MGMT) promoter hypermethylation, MGMT expression and microsatellite instability (MSI), as well as to elucidate their correlation with clinical and pathological parameters in epithelial ovarian cancer. METHODS: Ovarian cancer tissue specimens (n = 86) were obtained after a staging operation. The MGMT gene was investigated by methylation-specific polymerase chain reaction (MSP) and MGMT expression status was analyzed using immunohistochemistry. MSI status was examined by the fluorescence-based PCR using five National Cancer Institute markers. RESULTS: Negative MGMT expression was detected in 12 of 86 (14.0%) epithelial ovarian cancers. In 34 cases where MSP results were available, MGMT promoter hypermethylation was detected in five cases (14.7%) with mucinous or clear cell carcinomas, but not in any of other histological types (P = 0.031). Five out of six cases with negative MGMT expression showed MGMT promoter hypermethylation, whereas all of the 28 cases that retained expression of MGMT were unmethylated at the MGMT CpG island (P < 0.001). In 41 cases of MSI results available, seven (17.1%) cases showed MSI-H-phenotyped. Both MGMT promoter hypermethylation and negative MGMT expression were noted only in cases of mucinous or clear cell carcinoma in which MSI status were mostly MSS-phenotyped; however, no significant correlation was found between MSI status and clinicopathological parameters. CONCLUSIONS: Negative MGMT expression was significantly correlated with MGMT promoter hypermethylation in MSS-phenotyped tumors of mucinous or clear cell carcinoma. The results suggest that MGMT promoter hypermethylation might be associated with epithelial ovarian carcinogenesis in specific histological types.

TRIB2 Stimulates Cancer Stem-Like Properties through Activating the AKT-GSK3ß-ß-Catenin Signaling Axis.

Tribbles homolog 2 (TRIB2) is implicated in tumorigenesis and drug resistance in various types of cancers. However, the role of TRIB2 in the regulation of tumorigenesis and drug resistance of cancer stem cells (CSCs) is still elusive. In the present study, we showed increased expression of TRIB2 in spheroid-forming and aldehyde dehydrogenase-positive CSC populations of A2780 epithelial ovarian cancer cells. Short hairpin RNA-mediated silencing of TRIB2 expression attenuates the spheroid-forming, migratory, tumorigenic, and drug-resistant properties of A2780 cells, whereas overexpression of TRIB2 increases the CSC-like characteristics. TRIB2 overexpression induced GSK3ß inactivation by augmenting AKT-dependent phosphorylation of GSK3ß at Ser9, followed by increasing ß-catenin level via reducing the GSK3ß-mediated phosphorylation of ß-catenin. Treatment of TRIB2-ovexpressed A2780 cells with the phosphoinositide-3-kinase inhibitor LY294002 abrogated TRIB2-stimulated proliferation, migration, drug resistance of A2780 cells. These results suggest a critical role for TRIB2 in the regulation of CSC-like properties by increasing the stability of ß-catenin protein via the AKT-GSK3ß-dependent pathways.

CD166 promotes the cancer stem-like properties of primary epithelial ovarian cancer cells.

Cancer stem cells (CSCs) or tumor-initiating cells are thought to play critical roles in tumorigenesis, metastasis, drug resistance, and tumor recurrence. For the diagnosis and targeted therapy of CSCs, the molecular identity of biomarkers or therapeutic targets for CSCs needs to be clarified. In this study, we identified CD166 as a novel marker expressed in the sphereforming CSC population of A2780 epithelial ovarian cancer cells and primary ovarian cancer cells. The CD166+ cells isolated from A2780 cells and primary ovarian cancer cells highly expressed CSC markers, including ALDH1a1, OCT4, and SOX2, and ABC transporters, which are implicated in the drug resistance of CSCs. The CD166+ cells exhibited enhanced CSC-like properties, such as increased sphere-forming ability, cell migration and adhesion abilities, resistance to conventional anticancer drugs, and high tumorigenic potential in a xenograft mouse model. Knockdown of CD166 expression in the sphereforming ovarian CSCs abrogated their CSC-like properties. Moreover, silencing of CD166 expression in the sphere-forming CSCs suppressed the phosphorylation of focal adhesion kinase, paxillin, and SRC. These results suggest that CD166 plays a key role in the regulation of CSC-like properties and focal adhesion kinase signaling in ovarian cancer. [BMB Reports 2020; 53(12): 622-627].

Cancer-derived lysophosphatidic acid stimulates differentiation of human mesenchymal stem cells to myofibroblast-like cells.

Lysophosphatidic acid (LPA) is enriched in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests cancer-associated myofibroblasts play a pivotal role in tumorigenesis through secreting stromal cell-derived factor-1 (SDF-1). In the present study, we demonstrate that LPA induces expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in human adipose tissue-derived mesenchymal stem cells (hADSCs). The LPA-induced expression of alpha-SMA was completely abrogated by pretreatment of the cells with Ki16425, an antagonist of LPA receptors, or by silencing LPA(1) or LPA(2) isoform expression with small interference RNA (siRNA). LPA elicited phosphorylation of Smad2/3, and siRNA-mediated depletion of endogenous Smad2/3 or adenoviral expression of Smad7, an inhibitory Smad, abrogated the LPA induced expression of alpha-SMA and phosphorylation of Smad2/3. LPA-induced secretion of transforming growth factor (TGF)-beta1 in hADSCs, and pretreatment of the cells with SB431542, a TGF-beta type I receptor kinase inhibitor, or anti-TGF-beta1 neutralizing antibody inhibited the LPA-induced expression of alpha-SMA and phosphorylation of Smad2. Furthermore, ascites from ovarian cancer patients or conditioned medium from ovarian cancer cells induced expression of alpha-SMA and phosphorylation of Smad2, and pretreatment of the cells with Ki16425 or SB431542 abrogated the expression of alpha-SMA and phosphorylation of Smad2. In addition, LPA increased the expression of SDF-1 in hADSCs, and pretreatment of the cells with Ki16425 or SB431562 attenuated the LPA-stimulated expression of SDF-1. These results suggest that cancer-derived LPA stimulates differentiation of hADSCs to myofibroblast-like cells and increases SDF-1 expression through activating autocrine TGF-beta1-Smad signaling pathway.

Developing Korean Academy of Medical Sciences Guideline for rating the impairment in mental and behavioral disorders; a comparative study of KNPA's new guidelines and AMA's 6th Guides.

Quantifying and rating the impairments due to mental and behavior disorders are difficult for their own characteristics. Korean Academy of Medical Sciences (KAMS) is developing guidelines of rating impairment in mental and behavioral disorders based on Korean Neuropsychiatric Association (KNPA)'s new guidelines. We compared the new KNPA's guidelines and the American Medical Association (AMA)'s 6th Guides in assessing impairment due to mental and behavioral disorders to develop new guidelines of KAMS. Two guidelines are different in diagnosing system, applicable disorders, qualification of assessors, application of scales, contents of assessment and rate of impairment of the whole person. Both AMA's and the proposed guidelines have individual merits and characteristics. There is a limitation in using the 6th AMA's Guides in Korean situation. However to improve objectivity in Korean assessment of psychiatric impairment, the new AMA's Guides can serve as a good reference.

The Efficacy of Body Mass Index and Total Body Fat Percent in Diagnosis Obesity according to Menopausal Status.

OBJECTIVES: Body mass index (BMI) is commonly used in epidemiological study or clinical center. However, it is not exactly correlated with body fat composition and does not reflect sex, age, or race. The aim of this article is to evaluate the validity of BMI standards relative to total body fat (TBF) and to estimate new BMI criteria that correspond to TBF for obesity, especially for Asian postmenopausal women. METHODS: A total 3,936 patients were included in this cross-sectional study, including 1,565 premenopausal and 2,371 postmenopausal women. At the time of visit, demographic data were collected. We demonstrated the validity of BMI cut-point of 25 kg/m2 by using area under the curve (AUC), and presented the empirical optimal BMI cut-point by using Youden's index and overall accuracy in both premenopausal and postmenopausal women. RESULTS: BMI-defined obesity (≥ 25 kg/m2) represents high AUC values (> 0.9) for each TBF. In premenopausal women, TBF ≥ 38% and corresponding BMI value was 29.45 kg/m2 indicated the highest both Youden's index and overall accuracy. In comparison, postmenopausal women who were TBF ≥ 38% showed the highest Youden's index and overall accuracy, and corresponding BMI value was 26.45 kg/m2. CONCLUSIONS: We proposed new BMI criteria for obesity by using TBF reference. With application of bioelectrical impedance analysis, the diagnosis of obesity using BMI criteria may differ between premenopausal and postmenopausal women.

Lysophosphatidic acid in malignant ascites stimulates migration of human mesenchymal stem cells.

Lysophosphatidic acid (LPA) is elevated in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests a pivotal role of mesenchymal stem cells (MSCs) or stromal cells in tumorigenesis. In the present study, we demonstrated that ascites from ovarian cancer patients and LPA increased migration of human MSCs. The migration of MSCs induced by LPA and malignant ascites was completely abrogated by pretreatment with Ki16425, an antagonist of LPA receptors, and by silencing of endogenous LPA(1), but not LPA(2), with small interference RNA, suggesting a key role of LPA played in the malignant ascites-induced migration. LPA induced activation of ERK through pertussis toxin-sensitive manner, and pretreatment of MSCs with U0126, a MEK inhibitor, or pertussis toxin attenuated the LPA-induced migration. Moreover, LPA induced activation of RhoA in MSCs, and pretreatment of the cells with Y27632, a Rho kinase inhibitor, markedly inhibited the LPA-induced migration. In addition, LPA and malignant ascites increased intracellular concentration of calcium in MSCs, and Ki16425 completely inhibited the elevation of intracellular calcium. These results suggest that LPA is a crucial component of the malignant ascites which induce the migration of MSCs and elevation of intracellular calcium.

Lysophosphatidic acid induces cell migration through the selective activation of Akt1.

Akt plays pivotal roles in many physiological responses including growth, proliferation, survival, metabolism, and migration. In the current studies, we have evaluated the isoform-specific role of akt in lysophosphatidic acid (LPA)-induced cell migration. Ascites from ovarian cancer patients (AOCP) induced mouse embryo fibroblast (MEF) cell migration in a dose-dependent manner. On the other hand, ascites from liver cirrhosis patients (ALCP) did not induce MEF cell migration. AOCP-induced MEF cell migration was completely blocked by pre-treatment of cells with LPA receptor antagonist, Ki16425. Both LPA- and AOCP-induced MEF cell migration was completely attenuated by PI3K inhibitor, LY294002. Furthermore, cells lacking Akt1 displayed defect in LPA-induced cell migration. Re-expression of Akt1 in DKO (Akt1-/-Akt2-/-) cells restored LPA-induced cell migration, whereas re-expression of Akt2 in DKO cells could not restore the LPA-induced cell migration. Finally, Akt1 was selectively phosphorylated by LPA and AOCP stimulation. These results suggest that LPA is a major factor responsible for AOCP-induced cell migration and signaling specificity of Akt1 may dictate LPA-induced cell migration.

TRRAP stimulates the tumorigenic potential of ovarian cancer stem cells.

Ovarian cancer is the most fatal gynecological malignancy in women and identification of new therapeutic targets is essential for the continued development of therapy for ovarian cancer. TRRAP (transformation/transcription domain-associated protein) is an adaptor protein and a component of histone acetyltransferase complex. The present study was undertaken to investigate the roles played by TRRAP in the proliferation and tumorigenicity of ovarian cancer stem cells. TRRAP expression was found to be up-regulated in the sphere cultures of A2780 ovarian cancer cells. Knockdown of TRRAP significantly decreased cell proliferation and the number of A2780 spheroids. In addition, TRRAP knockdown induced cell cycle arrest and increased apoptotic percentages of A2780 sphere cells. Notably, the mRNA levels of stemness-associated markers, that is, OCT4, SOX2, and NANOG, were suppressed in TRRAP-silenced A2780 sphere cells. In addition, TRRAP overexpression increased the mRNA level of NANOG and the transcriptional activity of NANOG promoter in these cells. Furthermore, TRRAP knockdown significantly reduced tumor growth in a murine xenograft transplantation model. Taken together, the findings of the present study suggest that TRRAP plays an important role in the regulation of the proliferation and stemness of ovarian cancer stem cells. [BMB Reports 2018; 51(10): 515-520].

D-pinitol inhibits Th1 polarization via the suppression of dendritic cells.

d-pinitol has been demonstrated to exert insulin-like and anti-inflammatory effects. However, the effects of the maturation and immunostimulatory functions of dendritic cells (DC) remain to be clearly elucidated. In this study, we have attempted to determine whether d-pinitol regulates surface molecule expression, cytokine production, endocytosis capacity, and underlying signaling pathways in murine bone marrow-derived DC. We also attempted to ascertain whether d-pinitol could influence Th1/Th2 immune response in vivo. The DC used in this study were derived from murine bone marrow cells, and were used as immature or LPS-stimulated mature DC. The DC were then assessed with regard to surface molecule expression, dextran-FITC uptake, cytokine production, capacity to induce T-cell differentiation, and underlying signaling pathways. d-pinitol was shown to significantly inhibit CD80, CD86, MHC class I, and MHC class II expression in the LPS-stimulated mature DC. The DC also evidenced impaired IL-12 expression and IFN-gamma production. The d-pinitol-treated DC were found to be highly efficient in regards to Ag capture via mannose receptor-mediated endocytosis. d-pinitol was also demonstrated to inhibit LPS-induced MAPKs activation and NF-kappaB nuclear translocation. Moreover, the d-pinitol-treated DC manifested impaired induction of Th1 responses, and normal cell-mediated immune responses. These novel findings provide new insight into the immunopharmacological role of d-pinitol in terms of its effects on DC. These findings also broaden current perspectives concerning our understanding of the immunopharmacological functions of d-pinitol, and have ramifications for the development of therapeutic adjuvants for the treatment of DC-related acute and chronic diseases.