Aggressiveness Of Ovarian Cancer Cells Research Articles

Protective Effects of Nettle Tea on SKOV-3 Ovarian Cancer Cells Through ROS Production, Apoptosis Induction, and Motility Inhibition Without Altering Autophagy.

Urtica dioica L. (UD), also known as the stinging nettle, has long been used in traditional medicine for its wide range of health benefits. The current study focuses on the effect of nettle tea on the growth and proliferation of one of the most aggressive ovarian adenocarcinoma cell line, SKOV-3 cells. To examine this, cytotoxicity, cell cycle analysis, and ROS assays were performed, along with Annexin V/PI dual staining, cell death ELISA, Western blot analysis, and motility assays. The results showed that a UD aqueous extract (UDAE) can inhibit the growth and proliferation of SKOV-3 cells in a dose- and time-dependent manner by promoting cellular fragmentation. This was accompanied by an increase in two apoptotic hallmarks, the flipping of phosphatidylserine to the outer membrane leaflet and DNA fragmentation as revealed by cell death ELISA. This aqueous extract showed a pro-oxidant activity while also activating the extrinsic caspase-dependent apoptotic pathway with no alteration in autophagy markers. Furthermore, the extract showed promising inhibitory effect on the migratory capacities of aggressive ovarian cancer cells, in vitro.

RBN-2397, a PARP7 Inhibitor, Synergizes with Paclitaxel to Inhibit Proliferation and Migration of Ovarian Cancer Cells.

Mono(ADP-ribosyl)ation (MARylation), a post translational modification of proteins, is emerging as an important regulator of the biology of cancer cells. PARP7 (TiPARP), a mono (ADP-ribosyl) transferase (MART), MARylates its substrate α-tubulin in ovarian cancer cells, promoting destabilization of microtubules, cell growth, and migration. Recent development of RBN-2397, a potent inhibitor that selectively acts on PARP7, has provided a new tool for exploring the role of PARP7 catalytic activity in biological processes. In this study, we investigated the role of PARP7 catalytic activity in the regulation of ovarian cancer cell biology via MARylation of α-tubulin. Ovarian cancer cell lines (OVCAR4, OVCAR3) were treated with RBN-2397 and paclitaxel, both separately and in combination. Western blotting and immunoprecipitation confirmed the effects of RBN-2397 on α-tubulin MARylation and stabilization. Cell proliferation and migration were assessed, and α-tubulin stabilization was quantified using immunofluorescent imaging. RNA-sequencing was performed to assess the effects on gene expression changes. RBN-2397 inhibited PARP7 activity, decreasing α-tubulin MARylation, leading to its stabilization, and reducing cancer cell proliferation and migration. The addition of paclitaxel further enhanced these effects, highlighting a synergistic interaction between the two drugs. Mutating the site of PARP7-mediated MARylation on α-tubulin similarly resulted in microtubule stabilization and decreased cell migration in the presence of paclitaxel. This study demonstrates that targeting PARP7 with RBN-2397, particularly in combination with paclitaxel, offers an effective strategy for inhibiting aggressive ovarian cancer cell phenotypes. Our findings underscore the potential of combining PARP7 inhibitors with established chemotherapeutics to enhance treatment efficacy in ovarian cancer.

Abstract 1878: CTPS1: An unexplored vulnerability in breast and ovarian cancer

Abstract Breast and ovarian cancer represent the most common cancer types in women worldwide and are among the top fatal cancers. Despite the use of cytotoxic chemotherapy and targeted agents, recurrence is frequent and survival rates for patients with advanced metastatic disease are dismal. These realities highlight the need to identify novel biomarkers and therapeutic vulnerabilities in such tumors and to develop alternative treatment strategies. We took an unbiased approach to tackle this problem in which we leveraged publically available (DepMap) and in-house generated genome-wide CRISPR screens conducted in over 1000 cancer cell lines. We initially focused on the identification of essential genes that were unique to triple-negative breast cancer (TNBC) cells and whose expression levels were associated with worse patient outcomes. This interrogation revealed six genes (CTPS1, RHOA, PRKRA, RAD9A, HUS1, and RAD1) meeting these initial criteria. The essentiality of these genes was validated using gene-specific siRNAs in a panel of TNBC cells and knockdown of CTPS1 was shown to elicit the most inhibitory effect. CTPS1 depletion resulted in a rapid S-phase cell cycle arrest followed by apoptosis, not only in TNBC cells but also in highly aggressive ovarian cancer cells which share many molecular features with TNBC. CTPS1 converts uridine triphosphate to cytidine triphosphate, forming an essential nucleic acid required for multiple cellular processes. CTPS1 mRNA expression was substantially elevated in tumor vs. normal tissue, for both breast and ovarian cancer. Using over 40 breast and ovarian cancer cell lines, RT-PCR analyses confirmed increased expression of CTPS1 in TNBC and most ovarian cancer cell lines compared to other disease sub-types and “normal” cell line/tissue controls. Interestingly, chemoresistant and PARP inhibitor-resistant models exhibited the highest levels of CTPS1 among all cells analyzed. We subsequently identified and acquired STP938, a first-in-class highly selective CTPS1 inhibitor being developed by Step-Pharma. STP938 was found to elicit potent anti-cancer effects at nM concentrations across many cell line and patient-derived models, in both 2D and 3D culture systems. RNAseq analysis in aggressive cell line models following STP938 treatment or CTPS1 knockdown revealed significant regulation of genes related to DNA replication and the cell cycle pathways suggesting that combinatorial/sequential treatments of STP938 with replication stress/DNA damage response related drugs may be synergistic. STP938 is currently being developed for the treatment of lymphoma, and our findings support the repurposing of STP938 for breast and ovarian cancer, an avenue that we are currently developing. Citation Format: Xiyin Wang, Michael Emch, Lauren Voll, Rebecca Russell, Esther Rodman, Nicole Pearson, Xiaonan Hou, Scott Kaufmann, Saravut Weroha, Philip Beer, John Hawse. CTPS1: An unexplored vulnerability in breast and ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1878.

Purinergic Activation of Store-Operated Calcium Entry (SOCE) Regulates Cell Migration in Metastatic Ovarian Cancer Cells.

Store-operated calcium entry (SOCE) is an important process in calcium signaling. Its role in physiological and pathological events is well recognized. However, in cancerous systems, the importance of SOCE in relation to the degree of cancer aggressiveness, as well as its regulation by ligands such as purinergic molecules, are not well documented. This study aimed to characterize a differential effect of the P2Y2 receptor (promoted by UTP of 10 µM and inhibited by ARC118925XX of 1 µM) on intracellular calcium response between metastatic (SKOV-3) and non-metastatic (CAOV-3) ovarian cell lines in conditions of normal (1.5 mM) and zero extracellular calcium concentration. The sustained calcium influx observed exclusively in SKOV-3 cells was associated with the presence of SOCE (promoted by thapsigargin (74.81 ± 0.94 ΔF) and sensitive to 2-APB (20.60 ± 0.85 ΔF)), whereas its absence in CAOV-3 cells (26.2 ± 6.1 ΔF) was correlated with a low expression of ORAI1. The relevance of SOCE in metastatic SKOV-3 cells was further corroborated when 2-APB significantly inhibited (40.4 ± 2.8% of covered area) UTP-induced cell migration (54.6 ± 3.7% of covered area). In conclusion, our data suggest that SOCE activation elicited by the P2Y2 receptor is involved in the aggressiveness of ovarian cancer cells.

New progress of glutamine metabolism in the occurrence, development, and treatment of ovarian cancer from mechanism to clinic.

Glutamine is a non-essential amino acid that can be synthesized by cells. It plays a vital role in the growth and proliferation of mammalian cells cultured in vitro. In the process of tumor cell proliferation, glutamine not only contributes to protein synthesis but also serves as the primary nitrogen donor for purine and pyrimidine synthesis. Studies have shown that glutamine-addicted tumor cells depend on glutamine for survival and reprogram glutamine utilization through the Krebs cycle. Potential therapeutic approaches for ovarian cancer including blocking the entry of glutamine into the tricarboxylic acid cycle in highly aggressive ovarian cancer cells or inhibiting glutamine synthesis in less aggressive ovarian cancer cells. Glutamine metabolism is associated with poor prognosis of ovarian cancer. Combining platinum-based chemotherapy with inhibition of glutamine metabolic pathways may be a new strategy for treating ovarian cancer, especially drug-resistant ovarian cancer. This article reviews the role of glutamine metabolism in the biological behaviors of ovarian cancer cells, such as proliferation, invasion, and drug resistance. Its potential use as a new target or biomarker for ovarian cancer diagnosis, treatment, and the prognosis is investigated.

TRIM37 promotes the aggressiveness of ovarian cancer cells and increases c-Myc expression by binding to HUWE1

Tripartite motif containing 37 (TRIM37) was reported to function as a tumor promoter in the development of various cancers. However, the biological role of TRIM37 in ovarian cancer (OC) was still unclear. Expressions of TRIM37 and HUWE1 were detected by qRT-PCR and western blotting in OC cells. Cell proliferation was evaluated by CCK-8 assay and colony formation assay. Cell migration and invasion capabilities were examined by wound healing and transwell assay. Flow cytometry and western blotting were performed to measure cell apoptosis. Wnt/β-catenin pathway and the expression of c-Myc were identified by qRT-PCR and western blotting. The binding of TRIM37 and HUWE1 was predicted by STRING database and verified by co-immunoprecipitation. In addition, a xenograft mouse model was established to evaluate the effects of TRIM37 and HUWE1 on tumor growth and c-MYC expression in vivo. The present study revealed that TRIM37 expression was upregulated in OC tissues and cells. TRIM37 silencing inhibited OC cell migration and invasion, promoted OC cell apoptosis, and blocked Wnt/β-catenin signaling pathway, as well as suppressing c-MYC protein expression. Mechanistic studies suggested that TRIM37 binds to HUWE1. HUWE1 was upregulated in OC cells and TRIM37 promoted the c-MYC expression through targeting HUWE1. Animal experiments showed that TRIM37 silencing significantly repressed the tumor growth and c-MYC protein level, but HUWE1 overexpression reversed the effects of TRIM37 knockdown on mice with OC. Our findings revealed that TRIM37 accelerated the progression of OC and promoted c-MYC expression by binding to HUWE1, which provides therapeutic targets for OC treatment.

Differential effects of nanosecond pulsed electric fields on cells representing progressive ovarian cancer

Nanosecond pulsed electric fields (nsPEFs) may induce differential effects on tumor cells from different disease stages and could be suitable for treating tumors by preferentially targeting the late-stage/highly aggressive tumor cells. In this study, we investigated the nsPEF responses of mouse ovarian surface epithelial (MOSE) cells representing progressive ovarian cancer from benign to malignant stages and highly aggressive tumor-initiating-like cells. We established the cell-seeded 3D collagen scaffolds cultured with or without Nocodazole (eliminating the influence of cell proliferation on ablation outcome) to observe the ablation effects at 3 h and 24 h after treatment and compared the corresponding thresholds obtained by numerically calculated electric field distribution. The results showed that nsPEFs induced larger ablation areas with lower thresholds as the cell progress from benign, malignant to a highly aggressive phenotype. This differential effect was not affected by the different doubling times of the cells, as apparent by similar ablation induction after a synergistic treatment of nsPEFs and Nocodazole. The result suggests that nsPEFs could induce preferential ablation effects on highly aggressive and malignant ovarian cancer cells than their benign counterparts. This study provides an experimental basis for the research on killing malignant tumor cells via electrical treatments and may have clinical implications for treating tumors and preventing tumor recurrence after treatment.

Discovery of Monoacylglycerol Lipase (MAGL) Inhibitors Based on a Pharmacophore-Guided Virtual Screening Study.

Monoacylglycerol lipase (MAGL) is an important enzyme of the endocannabinoid system that catalyzes the degradation of the major endocannabinoid 2-arachidonoylglycerol (2-AG). MAGL is associated with pathological conditions such as pain, inflammation and neurodegenerative diseases like Parkinson’s and Alzheimer’s disease. Furthermore, elevated levels of MAGL have been found in aggressive breast, ovarian and melanoma cancer cells. Due to its different potential therapeutic implications, MAGL is considered as a promising target for drug design and the discovery of novel small-molecule MAGL inhibitors is of great interest in the medicinal chemistry field. In this context, we developed a pharmacophore-based virtual screening protocol combined with molecular docking and molecular dynamics simulations, which showed a final hit rate of 50% validating the reliability of the in silico workflow and led to the identification of two promising and structurally different reversible MAGL inhibitors, VS1 and VS2. These ligands represent a valuable starting point for structure-based hit-optimization studies aimed at identifying new potent MAGL inhibitors.

LncRNA TMPO-AS1 promotes LCN2 transcriptional activity and exerts oncogenic functions in ovarian cancer.

Ovarian cancer remains the sixth most frequently occurring cancer in women worldwide. Long noncoding RNAs (lncRNAs) are capable of regulating gene expression, and thus, participating in a wide range of biological functions and disease processes including cancer development. Our work suggests that lncRNA TMPO antisense RNA 1 (TMPO-AS1) represents an oncogenic lncRNA in ovarian cancer and presents a novel mechanism involving transcription factor E2F transcription factor 6 (E2F6) and lipocalin-2 (LCN2). We identified upregulated lncRNA TMPO-AS1 in ovarian cancer tissues and cells. siRNA-mediated silencing of lncRNA TMPO-AS1 restrained the aggressiveness of ovarian cancer cells and their pro-angiogenic ability, and reduced the expression of LCN2. LncRNA TMPO-AS1 was found to interact with E2F6, a transcriptional repressor that could bind to the promoter region of LCN2 gene. In addition, silencing of E2F6 or overexpression of LCN2 restored the aggressiveness of ovarian cancer cells and their pro-angiogenic ability following siRNA-mediated silencing of lncRNA TMPO-AS1. Taken together, we demonstrated lncRNA TMPO-AS1 could potentially promote LCN2 transcriptional activity by binding to transcription factor E2F6, and thus, stimulated the progression of ovarian cancer. These findings underscore a possible alternative therapeutic strategy for ovarian cancer treatment.

RNA demethylase ALKBH5 promotes ovarian carcinogenesis in a simulated tumour microenvironment through stimulating NF-κB pathway.

Methylation is the main form of RNA modification. N6‐methyladenine (m6A) regulates the splicing and translation of mRNA. Alk B homologue 5 (ALKBH5) participates in the biological regulation of various cancers. However, its role in ovarian carcinogenesis has not been unveiled. In the present study, ALKBH5 showed higher expression in ovarian cancer tissue than in normal ovarian tissue, but lower expression in ovarian cancer cell lines than in normal ovarian cell lines. Interestingly, Toll‐like receptor (TLR4), a molecular functioning in tumour microenvironment (TME), demonstrated the same expression trend. To investigate the effect of abnormal TME on ovarian carcinogenesis, we established an in vitro model in which macrophages and ovarian cancer cells were co‐cultured. In the ovarian cancer cells co‐cultured with M2 macrophages, the expression of ALKBH5 and TLR4 increased. We also verified that TLR4 up‐regulated ALKBH5 expression via activating NF‐κB pathway. Depending on transcriptome sequencing, m6A‐Seq and m6A MeRIP, we found that NANOG served as a target in ALKBH5‐mediated m6A modification. NANOG expression increased after mRNA demethylation, consequently enhancing the aggressiveness of ovarian cancer cells. In conclusion, highly expressed TLR4 activated NF‐κB pathway, up‐regulated ALKBH5 expression and increased m6A level and NANOG expression, all contributing to ovarian carcinogenesis. Our study revealed the role of m6A in ovarian carcinogenesis, providing a clue for inventing new target therapy.

TBC1D8 Amplification Drives Tumorigenesis through Metabolism Reprogramming in Ovarian Cancer.

Cancer cells undergo metabolic reprogramming to support their energy demand and biomass synthesis. However, the mechanisms driving cancer metabolism reprogramming are not well understood.Methods: The differential proteins and interacted proteins were identified by proteomics. Western blot, qRT-PCR and IHC staining were used to analyze TBC1D8 levels. In vivo tumorigenesis and metastasis were performed by xenograft tumor model. Cross-Linking assays were designed to analyze PKM2 polymerization. Lactate production, glucose uptake and PK activity were determined.Results: We established two aggressive ovarian cancer (OVCA) cell models with increased aerobic glycolysis. TBC1D8, a member of the TBC domain protein family, was significantly up-regulated in the more aggressive OVCA cells. TBC1D8 is amplified and up-regulated in OVCA tissues. OVCA patients with high TBC1D8 levels have poorer prognoses. TBC1D8 promotes OVCA tumorigenesis and aerobic glycolysis in a GAP activity-independent manner in vitro and in vivo. TBC1D8 bound to PKM2, not PKM1, via its Rab-GAP TBC domain. Mechanistically, TBC1D8 binds to PKM2 and hinders PKM2 tetramerization to decreases pyruvate kinase activity and promote aerobic glycolysis, and to promote the nuclear translocation of PKM2, which induces the expression of genes which are involved in glucose metabolism and cell cycle.Conclusions: TBC1D8 drives OVCA tumorigenesis and metabolic reprogramming, and TBC1D8 serves as an independent prognosis factor for OVCA patients.

Abstract B64: The novel ZIP4 regulation and its role in cancer stem cell-related activities in ovarian cancer

Abstract The role and regulation of ZIP4, a zinc (Zn) transporter, have been studied in the context of extracellular Zn transporting. Factors other than Zn with ZIP4 regulatory effects are essentially unknown. In addition, its role in cancer stem cell (CSC) has not been reported in any type of cancer. RNA-seq analyses were conducted to compare genes differentially expressed in less and more aggressive epithelial ovarian cancer (EOC) cells. ZIP4 expression and its regulation was assessed by immunoblotting, quantitative PCR, or immunofluorescence staining in human ovarian tissues. CSC-related activities were examined to evaluate the role of ZIP4 in human high-grade serous ovarian cancer (HGSOC) cells. RNAi and CRISPR techniques were used to knock down or knock out ZIP4 and related genes. EOC tumors overexpressed ZIP4 when compared with normal and benign tissues. ZIP4 knockout significantly reduced several CSC-related activities in EOC cells, including proliferation, anoikis resistance, colony formation, spheroid formation, drug resistance, and side-population (SP). Only ZIP4-expressing SP highly expressed known CSC markers ALDH1 and OCT4. ZIP4 knockout dramatically reduced tumorigenesis and ZIP4 overexpression increased tumorigenesis in vivo. In addition, the ZIP4-expressing SP population had the tumor initiating activity. Moreover, the oncolipid lysophosphatic acid (LPA) effectively upregulated ZIP4 expression via the nuclear receptor peroxisome proliferator-activated receptor gamma, and LPA’s promoting effects in CSC-related activities in HGSOC cells was at least partially mediated by ZIP4 in an extracellular Zn-independent manner. Our critical data imply that ZIP4 is a new and important cancer stem cell regulator in EOC. Our data also provide an innovative interpretation for the apparent disconnection between low levels of zinc and upregulation of ZIP4 in EOC tissues. Citation Format: Yan Xu, Qipeng Fan, Qingchun Cai, Kenneth P. Nephew. The novel ZIP4 regulation and its role in cancer stem cell-related activities in ovarian cancer. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B64.

Pegylated liposomal‑paclitaxel induces ovarian cancer cell apoptosis via TNF‑induced ERK/AKT signaling pathway.

Ovarian cancer is one of the most common gynecological types of cancer and is characterized by a relatively high incidence and high mortality rate. Evidence has demonstrated that paclitaxel (PTX) is an effective therapeutic treatment for human ovarian cancer. In the present study, the inhibitory effects of pegylated liposomal (PL)-PTX on the growth of ovarian cancer cells were investigated in vitro; a CAOV-3-bearing mouse model was established to investigate the in vivo effects of PL-PTX on ovarian tumor growth. In the present study, the underlying mechanism of tumor necrosis factor (TNF)-induced inhibition of extracellular signal-regulated kinase (ERK)/protein kinase B (AKT) signaling pathway mediated by PL-PTX was analyzed within ovarian cancer cells. The results of the present study revealed that PL-PTX significantly inhibited the growth and aggressiveness of ovarian cancer cells in vitro and in vivo and apoptotic ability increased upon administration of PL-PTX. The expression levels of caspase-3/9 were significantly upregulated within PL-PTX-treated ovarian cancer cells. The expression and phosphorylation levels of ERK and AKT were markedly increased in response to PL-PTX treatment. In addition, the inhibitory effects of PL-PTX on ovarian cancer cells were eliminated by neutralizing antibodies against TNF. The observations of the present study revealed that PL-PTX induced ovarian cell apoptosis via the TNF-dependent pathway, which was significantly inhibited with the employment of antibodies against TNF. In vivo analysis demonstrated that PL-PTX treatment significantly inhibited ovarian tumor growth and prolonged the survival of tumor bearing mice. In conclusion, the findings of the present study have provided an insight into the potential mechanism of PL-PTX-induced apoptosis of ovarian cancer cells. As PL-PTX has been reported to induce ovarian tumor cell apoptosis via the TNF-induced ERK/AKT signaling pathway, PL-PTX may serve as an efficient anticancer drug for the treatment of ovarian cancer.

SUSD2 promotes cancer metastasis and confers cisplatin resistance in high grade serous ovarian cancer

The activation of Notch3 is associated with potential progression of ovarian cancer, tumor invasion, metastasis and chemoresistance, which account for poor prognosis of high grade serous ovarian cancer (HGSOC). However, the underlying mechanisms of Notch3 are not yet very clear. Here we show that SUSD2 is one of Notch3-regulating genes and the elevated protein expression of SUSD2 in HGSOC. We also found that its high expression level was significantly correlated with worse overall survival, early recurrence and lymph nodes metastasis. Moreover, overexpression of SUSD2 in ovarian cancer cells promoted epithelial-mesenchymal transition (EMT) and the metastatic capacity of malignant cells. In contrast, silencing SUSD2 in aggressive ovarian cancer cells inhibited these processes both in vitro and in vivo. Mechanistically, we found SUSD2 promoted EMT through regulating the expression of EpCAM and EpCAM silencing reversed SUSD2-induced E-cadherin reduction and cells migration. Further experiments indicated a role of SUSD2 in conferring cisplatin resistance in ovarian cancer probably through enhancing autophagy in vitro. Collectively, these findings shed a new insight into the role of Notch3 downstream gene SUSD2 and provided a new therapeutic target for HGSOC.

Qualitative in vivo Bioluminescence Imaging

Bioluminescence imaging (BLI) technology is an advanced method of carrying out molecular imaging on live laboratory animals in vivo. This powerful technique is widely-used in studying a variety of biological processes, and it has been an ideal tool in exploring tumor growth and metastatic spread in real-time. This technique ensures the optimal use of laboratory animal resources, particularly the ethical principle of reduction in animal use, given its non-invasive nature, ensuring that ongoing biological processes can be studied over time in the same animal, without the need to euthanize groups of mice at specific time points. In this protocol, the luciferase imaging technique was developed to study the effect of co-inoculating pericytes (contractile, αSMA+ mesenchymal stem cell-like cells, located abluminally in microvessels) on the growth and metastatic spread of ovarian cancers using an aggressive ovarian cancer cell line-OVCAR-5-as an example.

Activation of the LKB1‑SIK1 signaling pathway inhibits the TGF‑β‑mediated epithelial‑mesenchymal transition and apoptosis resistance of ovarian carcinoma cells.

Ovarian cancer is the most common and lethal type of gynecological malignancy, due to its invasiveness. The present study aimed to analyze the molecular mechanism underlying chemoresistance in ovarian carcinoma cells, which may lead to local migration toward adjacent tissues and long-distance metastasis to other organs. A total of 12 patients with ovarian fibroma were used to evaluate chemoresistance and chemosensitivity. The sensitivity and resistance of ovarian carcinoma cells was measured using apoptosis analysis, morphological observation, survival rate analysis, immunohistochemistry and immunostaining. The mechanism underlying the interaction between the epithelial-mesenchymal transition (EMT) and liver kinase B1 (LKB1)-salt-inducible kinase 1 (SIK1) signaling pathways was additionally investigated in ovarian carcinoma. The results of the present study demonstrated that ovarian carcinoma cells isolated from patients exhibited apoptosis resistance. Inhibition of TGF-β expression led to an inhibition of growth, migration and invasion, in addition to a promotion of apoptosis, in ovarian carcinoma cells treated with paclitaxel. Studies have indicated that the LKB1-SIK1 signaling pathway may be suppressed in ovarian carcinoma cells compared with normal ovarian cells, leading to activation of the EMT signaling pathway. The results of the present study demonstrated that upregulation of LKB1 promoted SIK1 expression and markedly suppressed the growth and aggressiveness of ovarian cancer cells. Upregulation of LKB1 additionally promoted apoptosis in ovarian carcinoma cells. In addition, the results of the present study demonstrated that the knockdown of LKB1 further promoted the expression of transforming growth factor-β and EMT, which downregulated the chemosensitivity of ovarian carcinoma cells. Additionally, overexpression of LKB1 in ovarian carcinoma cells increased chemosensitivity, resulting in a significant inhibition of migration and invasion. The present findings indicated that the enhancement of LKB1-SIK1 suppressed the growth and aggressiveness of ovarian carcinoma cells isolated from clinical patients, which subsequently contributed to an inhibition of metastatic potential. In conclusion, targeting the LKB1-SIK1 signaling pathway to inhibit EMT may provide potential therapeutic benefits in ovarian carcinoma.

Correction to: High expression of HO-1 predicts poor prognosis of ovarian cancer patients and promotes proliferation and aggressiveness of ovarian cancer cells.

n the original version of the article, Table2 was incorrect. The corrected Table2 is shown here. Therefore, in Results (page 3 of original version, right column, line 13), the OR of non-optimal debulking should read OR=3.036 with 95% CI 1.452-6.348.

The novel ZIP4 regulation and its role in ovarian cancer.

Our RNAseq analyses revealed that ZIP4 is a top gene up-regulated in more aggressive ovarian cancer cells. ZIP4's role in cancer stem cells has not been reported in any type of cancer. In addition, the role and regulation of ZIP4, a zinc transporter, have been studied in the context of extracellular zinc transporting. Factors other than zinc with ZIP4 regulatory effects are essentially unknown. ZIP4 expression and its regulation in epithelial ovarian cancer cells was assessed by immunoblotting, quantitative PCR, or immunohistochemistry staining in human ovarian tissues. Cancer stem cell-related activities were examined to evaluate the role of ZIP4 in human high-grade serous ovarian cancer cells in vitro and in vivo. RNAi and CRISPR techniques were used to knockdown or knockout ZIP4 and related genes. Ovarian cancer tissues overexpressed ZIP4 when compared with normal and benign tissues. ZIP4 knockout significantly reduced several cancer stem cell-related activities in EOC cells, including proliferation, anoikis-resistance, colony-formation, spheroid-formation, drug-resistance, and side-population in vitro. ZIP4-expressing side-population highly expressed known CSC markers ALDH1 and OCT4. ZIP4 knockout dramatically reduced tumorigenesis and ZIP4 overexpression increased tumorigenesis in vivo. In addition, the ZIP4-expressing side-population had the tumor initiating activity. Moreover, the oncolipid lysophosphatic acid effectively up-regulated ZIP4 expression via the nuclear receptor peroxisome proliferator-activated receptor gamma and lysophosphatic acid 's promoting effects in cancer stem cell-related activities in HGSOC cells was at least partially mediated by ZIP4 in an extracellular zinc-independent manner. Our critical data imply that ZIP4 is a new and important cancer stem cell regulator in ovarian cancer. Our data also provide an innovative interpretation for the apparent disconnection between low levels of zinc and up-regulation of ZIP4 in ovarian cancer tissues.

High expression of HO-1 predicts poor prognosis of ovarian cancer patients and promotes proliferation and aggressiveness of ovarian cancer cells

HO-1 has been proved to be associated with tumor aggressivity and poor prognosis in various cancers. Our study provides the first study to demonstrate the relationship of HO-1 expression and clinical characteristics in ovarian cancer patients. Immunohistochemistry and western blotting were used to examine the expression of HO-1 in tissue species and fresh tissues. CCK-8 was used to investigate cell viability. Transwell chamber was performed to estimate migration and invasion capacities in A2780 and Skov-3 cells. Immunohistochemistry and western blotting showed that the expression of HO-1 was higher in ovarian cancer tissues than normal ovarian tissues. High expression of HO-1 was significantly associated with serous ovarian cancer, high FIGO stage, lymph node metastasis, and non-optimal debulking. Patients with high expression of HO-1 exhibited an unfavorable prognosis. In vitro inducing the expression of HO-1 promoted the proliferation and metastasis of A2780 and Skov-3 cells, with the increased expressions of mesenchymal marker (Vimentin), epithelial-mesenchymal transition-associated transcript factor (Zeb-1), anti-apoptotic protein (Bcl-2), and the decreased expressions of epithelial marker (Keratin) and pro-apoptotic protein (Bax). Meanwhile, after incubating A2780 and Skov-3 together with HO-1 inhibitor, above results could be reversed. HO-1 might be a potential marker for prediction of ovarian cancer prognosis and a target for ovarian cancer treatment.

Abstract 606: Targeting multiple immune checkpoints and their ligands using a humanized mouse model of ovarian cancer

Abstract We have recently reported that multiple immune checkpoints are expressed in the TILs (tumor infiltrating T lymphocytes) and TALs (tumor associated T lymphocytes) from a murine ovarian cancer model and that blockade of one checkpoint pathway induces an upregulation of the other unblocked checkpoints. We hypothesized that resistance to single agent blockade (e.g. anti-PD1) is resulted from the compensatory upregulation of the other pathways (e.g. CTLA4 or LAG-3). To test this hypothesis in human ovarian cancer, we first examined the level of several immune checkpoints and their ligands in TILs or TALs from ovarian cancer patients. In addition to the highly expressed PD-1 and CTLA4, other checkpoint molecules such as TIM3, LAG3, VISTA, and TIGIT are also elevated in TALs as compared with control PBMC. The levels of multiple ligands for the immune receptors in the tumor samples were also analyzed. To translate the results from mice to humans, we developed several aggressive human ovarian cancer cell lines from patient derived xenografts to test the combinatorial checkpoint blockade strategies. Using a humanized mouse model of ovarian cancer we observed that adaptive transfer of autologous T cells in combination with checkpoint blockade of PD1 mildly delays ovarian tumor growth. The effect of blocking PD-1 and CTLA-4 pathways on tumor growth and the upregulation of other checkpoints are currently underway. Citation Format: Ruea-Yea Huang, Kunle Odunsi. Targeting multiple immune checkpoints and their ligands using a humanized mouse model of ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 606. doi:10.1158/1538-7445.AM2017-606