Fatty acid synthase expression associated with NAC1 is a potential therapeutic target in ovarian clear cell carcinomas

Fatty acid synthase: A key driver of ovarian cancer metastasis and a promising therapeutic target

Fatty acid synthase (FASN) is a critical enzyme essential for the production of fats in the body. The abnormal expression of FASN is associated with different types of malignancies, including ovarian cancer. FASN plays a crucial role in cell growth and survival as a metabolic oncogene, although the specific processes that cause its dysregulation are still unknown. FASN interacts with signaling pathways linked to the progression of cancer. Pharmacologically inhibiting or inactivating the FASN gene has shown potential in causing the death of cancer cells, offering a possible treatment approach. This review examines the function of FASN in ovarian cancer, namely its level of expression, influence on the advancement of the disease, and its potential as a target for therapeutic interventions.

NIPBL::NACC1 Fusion Hepatic Carcinoma

Several reports describing a rare primary liver tumor with histologic features reminiscent of follicular thyroid neoplasms have been published under a variety of descriptive terms including thyroid-like, solid tubulocystic, and cholangioblastic cholangiocarcinoma. Although these tumors are considered to represent histologic variants, they lack classic features of cholangiocarcinoma and have unique characteristics, namely immunoreactivity for inhibin and NIPBL::NACC1 fusions. The purpose of this study is to present clinicopathologic and molecular data for a large series of these tumors to better understand their pathogenesis. We identified 11 hepatic tumors with these features. Immunohistochemical and NACC1 and NIPBL fluorescence in situ hybridization assays were performed on all cases. Four cases had available material for whole-genome sequencing (WGS) analysis. Most patients were adult women (mean age: 42 y) who presented with abdominal pain and large hepatic masses (mean size: 14 cm). Ten patients had no known liver disease. Of the patients with follow-up information, 3/9 (33%) pursued aggressive behavior. All tumors were composed of bland cuboidal cells with follicular and solid/trabecular growth patterns in various combinations, were immunoreactive for inhibin, showed albumin mRNA by in situ hybridization, and harbored the NIPBL::NACC1 fusion by fluorescence in situ hybridization. WGS corroborated the presence of the fusion in all 4 tested cases, high tumor mutational burden in 2 cases, and over 30 structural variants per case in 3 sequenced tumors. The cases lacked mutations typical of conventional intrahepatic cholangiocarcinoma. In this report, we describe the largest series of primary inhibin-positive hepatic neoplasms harboring a NIPBL::NACC1 fusion and the first WGS analysis of these tumors. We propose to name this neoplasm NIPBL:NACC1 fusion hepatic carcinoma.

Updates of Pathogenesis, Diagnostic and Therapeutic Perspectives for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC) and has a high prevalence in Asia without specific molecular subtype classification. Endometriosis is a recognized precancerous lesion that carries 3-fold increased risk of OCCC. Ovarian endometrioid carcinoma, which also originates from endometriosis, shares several features with OCCC, including platinum resistance and younger age at diagnosis. Patients with OCCC have about a 2.5 to 4 times greater risk of having a venous thromboembolism (VTE) compared with other EOC, and OCCC tends to metastasize through lymphatic vesicular and peritoneal spread as opposed to hematogenous metastasis. There is only mild elevation of the conventional biomarker CA125. Staging surgery or optimal cytoreduction combined with chemotherapy is a common therapeutic strategy for OCCC. However, platinum resistance commonly portends a poor prognosis, so novel treatments are urgently needed. Targeted therapy and immunotherapy are currently being studied, including PARP, EZH2, and ATR inhibitors combined with the synthetic lethality of ARID1A-dificiency, and MAPK/PI3K/HER2, VEGF/bFGF/PDGF, HNF1β, and PD-1/PD-L1 inhibitors. Advanced stage, suboptimal cytoreduction, platinum resistance, lymph node metastasis, and VTE are major prognostic predictors for OCCC. We focus on update pathogenesis, diagnostic methods and therapeutic approaches to provide future directions for clinical diagnosis and treatment of OCCC.

lncRNA FOXP4‑AS1 predicts poor prognosis and accelerates the progression of mantle cell lymphoma through the miR‑423‑5p/NACC1 pathway

Long non‑coding RNA (lncRNA) forkhead box P4 antisense RNA 1 (FOXP4‑AS1) has been determined to function as an oncogene in various types of cancer. However, the biological function and the underlying mechanisms of FOXP4‑AS1 in mantle cell lymphoma (MCL) remain to be uncovered. The expression and the associated clinicopathological characteristics and prognostic significance of FOXP4‑AS1 were explored in MCL clinical samples. The effects of FOXP4‑AS1 on MCL cellular behaviors, including proliferation, migration and invasion were analyzed using CCK‑8, crystal violet and Transwell assays. The downstream molecules of FOXP4‑AS1 were explored using bioinformatics analysis and dual luciferase assay. Our results showed that FOXP4‑AS1 expression was upregulated in MCL patients, and that the high expression of FOXP4‑AS1 was correlated with the unfavorable prognosis of patients. Functionally, while FOXP4‑AS1 downregulation inhibited proliferation, migration and invasion of MCL cells, FOXP4‑AS1 overexpression had promotive effects on these cellular processes. Mechanistically, FOXP4‑AS1 was found to act as a competing endogenous (ce)RNA for miR‑423‑5p to regulate the expression of nucleus accumbens‑associated 1 (NACC1). The negative regulation of FOXP4‑AS1 on miR‑423‑5p compared to that of miR‑423‑5p on NACC1 was determined at the mRNA or protein levels in MCL cells. Moreover, an inverse expression correlation between FOXP4‑AS1 and miR‑423‑5p, and that between miR‑423‑5p and NACC1 was confirmed in MCL clinical samples. In addition, rescue assay showed that miR‑423‑5p upregulation or NACC1 knockdown abolished the promoting effects of FOXP4‑AS1 on MCL cell proliferation, migration and invasion. In conclusion, FOXP4‑AS1 promotes MCL progression through the upregulation of NACC1 expression by inhibiting miR‑423‑5p. FOXP4‑AS1 may serve as a novel therapeutic target for patients with MCL.

NACC-1 regulates hepatocellular carcinoma cell malignancy and is targeted by miR-760

Hepatocellular carcinoma (HCC) is the most prominent form of presentation in liver cancer. It is also the fourth most common cause of cancer-associated deaths globally. The role of nucleus accumbens associated protein-1 (NACC-1) has been evaluated in several cancers. This protein is a transcriptional regulator that regulates a number of significant cellular processes. In the current study, we aimed to understand the role of NACC-1 in HCC. Primarily, we measured the expression of NACC-1 using quantitative real time polymerase chain reaction and western blot analysis. We knocked down the expression of NACC-1 in HCC cell lines Huh7 and HepG2 by transferring a commercially synthesized small interfering RNA and explored the impact of NACC-1 knockdown on cellular growth, migration, invasion, and chemoresistance to doxorubicin. Through bioinformatic analysis, we identified NACC-1 as a potential target of miR-760. Using a dual reporter luciferase assay, we confirmed the predicted target and assessed miR-760-mediated regulation of NACC-1 and rescue of tumorigenic phenotypes. We observed increased expression of NACC-1 in HCC. Furthermore, knockdown of NACC-1 resulted in reduced cell proliferation and invasion and increased susceptibility to doxorubicin-mediated chemosensitivity. Overexpression of miR-760 in HCC cell lines rescued NACC-1-mediated migration and invasion. We revealed that miR-760 regulated NACC-1 expression in HCC. Our data indicated that both miR-760 and NACC-1 could be used as prognostic markers, and miR-760 may have therapeutic benefits for HCC and other cancers.

HPV Oncoproteins and the Ubiquitin Proteasome System: A Signature of Malignancy?

Human papillomavirus (HPV) E6 and E7 oncoproteins are critical for development and maintenance of the malignant phenotype in HPV-induced cancers. These two viral oncoproteins interfere with a plethora of cellular pathways, including the regulation of cell cycle and the control of apoptosis, which are critical in maintaining normal cellular functions. E6 and E7 bind directly with certain components of the Ubiquitin Proteasome System (UPS), enabling them to manipulate a number of important cellular pathways. These activities are the means by which HPV establishes an environment supporting the normal viral life cycle, however in some instances they can also lead to the development of malignancy. In this review, we have discussed how E6 and E7 oncoproteins from alpha and beta HPV types interact with the components of the UPS, and how this interplay contributes to the development of cancer.

SIK2 enhances synthesis of fatty acid and cholesterol in ovarian cancer cells and tumor growth through PI3K/Akt signaling pathway

Salt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

Lipid metabolism and Calcium signaling in epithelial ovarian cancer

Epithelial Ovarian cancer (EOC) is the deadliest gynecologic malignancy and represents the fifth leading cause of all cancer-related deaths in women. The majority of patients are diagnosed at an advanced stage of the disease that has spread beyond the ovaries to the peritoneum or to distant organs (stage FIGO III-IV) with a 5-year overall survival of about 29%. Consequently, it is necessary to understand the pathogenesis of this disease. Among the factors that contribute to cancer development, lipids and ion channels have been described to be associated to cancerous diseases particularly in breast, colorectal and prostate cancers. Here, we reviewed the literature data to determine how lipids or lipid metabolites may influence EOC risk or progression. We also highlighted the role and the expression of the calcium (Ca²⁺) and calcium-activated potassium (KCa) channels in EOC and how lipids might regulate them. Although lipids and some subclasses of nutritional lipids may be associated to EOC risk, lipid metabolism of LPA (lysophosphatidic acid) and AA (arachidonic acid) emerges as an important signaling network in EOC. Clinical data showed that they are found at high concentrations in EOC patients and in vitro and in vivo studies referred to them as triggers of the Ca²⁺entry in the cancer cells inducing their proliferation, migration or drug resistance. The cross-talk between lipid mediators and Ca²⁺ and/or KCa channels needs to be elucidated in EOC in order to facilitate the understanding of its outcomes and potentially suggest novel therapeutic strategies including treatment and prevention.

Ectopic Otoconin 90 expression in triple negative breast cancer cell lines is associated with metastasis functions

Triple negative breast cancer (TNBC) is an aggressive tumor with propensity to metastasize and poor treatment options. Improving treatment options would be impactful; thus, finding a tumor-specific cell surface protein with metastasis promoting functions that could be knocked out was the goal of this study. The Otoconin 90 gene (OC90), frequently amplified in tumors on chromosome 8q24.22, was identified as a potential therapeutic candidate. Normally OC90 is expressed in the cochlea with no known function in other normal tissues. In silico analysis of The Cancer Genome Atlas (TCGA) multi-tumor RNAseq cohorts revealed that OC90 is expressed in many tumor types at high prevalence and genomic amplification is associated with the elevated mRNA expression. In vitro assays in TNBC cell lines revealed OC90 expression with control over cell viability, apoptosis and invasion. RNA-seq analysis of OC90-siRNA knockdown and OC90-overexpression in BT20, BT549, HCC38 cell lines identified co-expressed transcripts, HMGA2, POLE2 and TRIB3. Altered expression of HMGA2, POLE2 and TRIB3 was predictive of survival among members of the Metabric breast cancer cohort. Thus, OC90 represents a potential therapeutic target whose knockdown could improve the treatment of TNBC.

NACC1, as a Target of MicroRNA-331-3p, Regulates Cell Proliferation in Urothelial Carcinoma Cells

The nucleus accumbens-associated protein 1 (NACC1) is a transcription factor constitutively expressed in the urothelium, where it regulates cell growth, senescence, autophagy, and epithelial-mesenchymal transition. microRNA (miRNA) constitutes a class of small non-coding RNAs which are involved in cell proliferation, differentiation, and progression of tumors. miRNAs and their target molecules are utilized for molecular diagnosis of urothelial carcinoma. NACC1 is one of several putative target molecules of miR-331-3p, and is associated with cell proliferation in cancers such as prostate and cervical cancer. Functional experiments involving miR-331-3p and its target molecule NACC1 were conducted using the urothelial carcinoma (UC) cell lines, T24, UMUC6, and KU7. Furthermore, quantitative reverse transcription polymerase chain reaction and immunostaining were performed to evaluate the expression of NACC1 in UC derived from transurethral resection of bladder tumor (TUR-Bt) specimens. The methane thiosulfonate (MTS) assay revealed that cell proliferation was significantly reduced after transient transfection of miR-331-3p precursor and/or NACC1 siRNA in UC cells. Cell senescence via cell cycle arrest at the G1 phase was induced by NACC1 inhibition. On the other hand, suppression of NACC1 induced cell migration and invasion abilities. Immunohistochemical analysis of TUR-Bt specimens revealed that over 70% of UC cells presented strongly positive results for NACC1. In contrast, normal urothelial cells were weakly positive for NACC1. It was also found that NACC1 expression was lower in invasive UC cells than in non-invasive UC cells. Loss of NACC1 induced vessel invasion in invasive UC tissues. The present results indicate that NACC1 regulated by miR-331-3p contributes to cell proliferation, and is involved in cell migration and invasion. This suggests that NACC1 can serve as a potential target molecule for the prediction and prognosis of UC, and can contribute to effective treatment strategies.

Crosstalk between osteoprotegerin (OPG), fatty acid synthase (FASN) and, cycloxygenase-2 (COX-2) in breast cancer: implications in carcinogenesis

The crosstalk between malignant and nonmalignant cells in the tumor microenvironment, as maneuvered by cytokines/chemokines, drives breast cancer progression. In our previous study, we discovered Osteoprotegerin (OPG) as one of the cytokines heavily secreted by breast cancer cells. We demonstrated that OPG is expressed and secreted at very high levels from the highly invasive breast cancer cell lines SUM149PT and SUM1315MO2 as compared to normal human mammary epithelial HMEC cells. OPG was involved in modulating aneuploidy, cell proliferation, and angiogenesis in breast cancer. Mass spectrometry analysis performed in this study revealed OPG interacts with fatty acid synthase (FASN), which is a key enzyme of the fatty acid biosynthetic pathway in breast cancer cells. Further, electron microscopy, immunofluorescence, and fluorescence quantitation assays highlighted the presence of a large number of lipid bodies (lipid droplets) in SUM149PT and SUM1315MO2 cells in comparison to HMEC. We recently showed upregulation of the COX-2 inflammatory pathway and its metabolite PGE2 secretion in SUM149PT and SUM1315MO2 breast cancer cells. Interestingly, human breast cancer tissue samples displayed high expression of OPG, PGE2 and fatty acid synthase (FASN). FASN is a multifunctional enzyme involved in lipid biosynthesis. Immunofluorescence staining revealed the co-existence of COX-2 and FASN in the lipid bodies of breast cancer cells. We reasoned that there might be crosstalk between OPG, FASN, and COX-2 that sustains the inflammatory pathways in breast cancer. Interestingly, knocking down OPG by CRISPR/Cas9 gene editing in breast cancer cells decreased FASN expression at the protein level. Here, we identified cis-acting elements involved in the transcriptional regulation of COX-2 and FASN by recombinant human OPG (rhOPG). Treatment with FASN inhibitor C75 and COX-2 inhibitor celecoxib individually decreased the number of lipid bodies/cell, downregulated phosphorylation of ERK, GSK3β, and induced apoptosis by caspase-3/7 and caspase-9 activation. But a more efficient and effective decrease in lipid bodies/cell and survival kinase signaling was observed upon combining the drug treatments for the aggressive cancer cells. Collectively, the novel biological crosstalk between OPG, FASN, and COX-2 advocates for combinatorial drug treatment to block these players of carcinogenesis as a promising therapeutic target to treat highly invasive breast cancer.

Nucleus accumbens-associated protein-1 promotes glycolysis and survival of hypoxic tumor cells via the HDAC4-HIF-1α axis

Nucleus accumbens-associated protein-1 (NAC1), a nuclear factor of the BTB/POZ gene family, has emerging roles in cancer. In this study, we identified the NAC1-HDAC4-HIF-1α axis as an important pathway in regulating glycolysis and hypoxic adaptation in tumor cells. We show that nuclear NAC1 binds to histone deacetylase type 4 (HDAC4), hindering phosphorylation of HDAC4 at Ser²⁴⁶ and preventing its nuclear export that leads to cytoplasmic degradation of the deacetylase. Accumulation of HDAC4 in the nuclei results in an attenuation of HIF-1α acetylation, enhancing the stabilization and transcriptional activity of HIF-1α and strengthening adaptive response of cells to hypoxia. We also show the role of NAC1 in promoting glycolysis in a mouse xenograft model, and demonstrate that knockdown of NAC1 expression can reinforce the antitumor efficacy of bevacizumab, an inhibitor of angiogenesis. Clinical implication of the NAC1-HDAC4-HIF-1α pathway is suggested by the results showing that expression levels of these proteins are significantly correlative in human tumor specimens and associated with the disease progression. This study not only reveals an important function of NAC1 in regulating glycolysis, but also identifies the NAC1-HDAC4-HIF-1α axis as a novel molecular pathway that promotes survival of hypoxic tumor cells.

Metabolic Regulation of Apoptosis in Cancer

Apoptosis is a cellular suicide program that plays a critical role in development and human diseases, including cancer. Cancer cells evade apoptosis, thereby enabling excessive proliferation, survival under hypoxic conditions, and acquired resistance to therapeutic agents. Among various mechanisms that contribute to the evasion of apoptosis in cancer, metabolism is emerging as one of the key factors. Cellular metabolites can regulate functions of pro- and antiapoptotic proteins. In turn, p53, a regulator of apoptosis, also controls metabolism by limiting glycolysis and facilitating mitochondrial respiration. Consequently, with dysregulated metabolism and p53 inactivation, cancer cells are well-equipped to disable the apoptotic machinery. In this article, we review how cellular apoptosis is regulated and how metabolism can influence the signaling pathways leading to apoptosis, especially focusing on how glucose and lipid metabolism are altered in cancer cells and how these alterations can impact the apoptotic pathways.

Nucleus Accumbens-Associated Protein 1 Expression Has Potential as a Marker for Distinguishing Oral Epithelial Dysplasia and Squamous Cell Carcinoma

Background

Oral epithelial dysplasia (OED) and carcinoma in situ (CIS) are defined by dysplastic cells in the epithelium. Over a third of oral squamous cell carcinoma (OSCC) patients present with associated OED. However, accurate histopathological diagnosis of such lesions is difficult. Nucleus accumbens-associated protein 1 (NAC1) is a member of the Pox virus and Zinc finger/Bric-a-brac Tramtrack Broad complex family of proteins, and is overexpressed in OSCC. This study aimed to determine whether NAC1 has the potential to be used as a marker to distinguish OED and OSCC.

Methods and Findings

The study included 114 patients (64 men, 50 women). There were 67, 10, and 37 patients with OED, CIS, and OSCC, respectively. NAC1 labeling indices (LIs) and immunoreactivity intensities (IRI) were evaluated. The patients’ pathological classification was significantly associated with age, sex, NAC1 LIs, and NAC1 IRI (p = 0.025, p = 0.022, p < 0.001, and p < 0.001, respectively). As a result of multivariate analysis, a predictive model was made; this identified the NAC1 LIs (OR [95% CI] 1.18 [1.11–1.28], p < 0.001) and NAC1 IRI (0.78 [0.68–0.86], p < 0.001) as predictive factors for CIS/OSCC. The NAC1 LIs/IRI cut-off values which discriminated between OED and CIS/OSCC were 50%/124 pixels. For NAC1 LIs with > 50% positivity the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 0.766, 0.910, 0.857, and 0.847, respectively. For NAC1 IRI with ≤ 124 positive pixels, the sensitivity, specificity, PPV, and NPV were 0.787, 0.866, 0.804, and 0.853, respectively. Though there are several potential limitations to this study and the results were obtained from a retrospective analysis of a single site cohort, the data suggest that the NAC1 LIs/IRI is a strong predictor of CIS/OSCC.

Conclusions

NAC1 has potential as a marker for distinguishing OED from CIS/OSCC.

Identification of novel candidate biomarkers of epithelial ovarian cancer by profiling the secretomes of three-dimensional genetic models of ovarian carcinogenesis

Epithelial ovarian cancer (EOC) is still considered the most lethal gynecological malignancy and improved early detection of ovarian cancer is crucial to improving patient prognoses. To address this need, we tested whether candidate EOC biomarkers can be identified using three-dimensional (3D) in vitro models. We quantified changes in the abundance of secreted proteins in a 3D genetic model of early-stage EOC, generated by expressing CMYC and KRAS(G) (12) (V) in TERT-immortalized normal ovarian epithelial cells. Cellular proteins were labeled in live cells using stable isotopic amino acid analogues, and secreted proteins identified and quantified using liquid chromatography-tandem mass spectrometry. Thirty-seven and 55 proteins were differentially expressed by CMYC and CMYC+KRAS(G) (12) (V) expressing cells respectively (p < 0.05; >2-fold). We evaluated expression of the top candidate biomarkers in ∼210 primary EOCs: CHI3L1 and FKBP4 are both expressed by >96% of primary EOCs, and FASN and API5 are expressed by 86 and 75% of cases. High expression of CHI3L1 and FKBP4 was associated with worse patient survival (p = 0.042 and p = 0.002, respectively). Expression of LGALS3BP was positively associated with recurrence (p = 0.0001) and suboptimal debulking (p = 0.018) suggesting that these proteins may be novel prognostic biomarkers. Furthermore, within early stage tumours (I/II), high expression of API5, CHI3L1 and FASN was associated with high tumour grade (p = 3 × 10(-4) , p = 0.016, p = 0.010, respectively). We show in vitro cell biology models of early-stage cancer development can be used to identify novel candidate biomarkers for disease, and report the identification of proteins that represent novel potential candidate diagnostic and prognostic biomarkers for this highly lethal disease.

The acetyl-CoA carboxylase enzyme: a target for cancer therapy?

As a rate-limiting enzyme, the acetyl-CoA carboxylase (ACC) is essential for fatty acid synthesis. Traditionally, the ACC has been a target of metabolic syndrome and obesity. Recent research has demonstrated that malignant tumors have a high energy flow, thus having a great ability to synthesize fatty acids. ACCs are occasionally found to be overexpressed in cancer cells, and using chemical or RNA interference to inhibit ACC can lead to cancer cell cycle arrest and apoptosis. This suggests that ACC and relative fatty acids may be critical for the survival of cancer cells. In this review, we summarize the role of ACC in tumor development. We also discuss the signaling pathways possibly affected by ACC, which may give insight into future research for cancer therapy.

Genetic variants in de novo lipogenic pathway genes predict the prognosis of surgically-treated hepatocellular carcinoma

Over-expression of de novo lipogenesis (DNL) pathway genes is associated with the prognosis of various types of cancers. However, effects of single nucleotide polymorphisms (SNPs) in these genes on recurrence and death of hepatocellular carcinoma (HCC) patients after surgery are still unknown. A total of 492 primary HCC patients treated with surgery were included in this study. Nine SNPs in 3 genes (ACACA, FASN and ACLY) of DNL pathway were genotyped. Multivariate Cox proportional hazard regression model and Kaplan-Meier curve were used to analyze the association of SNPs with clinical outcomes. Two SNPs in ACACA gene were significantly associated with overall survival of HCC patients. Patients carrying homozygous variant genotype (VV) in rs7211875 had significantly increased risk of death, while patients carrying VV genotype in rs11871275 had significant decreased risk of death, when compared with those carrying homozygous wild-type or heterozygous genotypes. Moreover, patients carrying VV genotype in rs11871275 had decreased recurrence risk, while patients carrying variant genotype in rs4485435 of FASN gene had increased recurrence risk. Further cumulative effect analysis showed significant dose-dependent effects of unfavorable SNPs on both death and recurrence. SNPs in DNL genes may serve as independent prognostic markers for HCC patients after surgery.

Verifying the markers of ovarian cancer using RNA-seq data

Markers associated with diagnosis, presentation and potential therapeutic targets have received widespread attention in ovarian cancer research in the past few years. However, the majority of these markers have been investigated individually, and the changes in expression and the association between them are rarely documented. Next‑generation sequencing, also termed RNA-seq when the sequencing targets are cDNAs, can provide a whole blueprint of the transcriptome of a specific tissue. In the present study, RNA-seq data of human ovarian cancer samples were used to verify the expression of known markers and to identify the association between them. A total of 563 markers associated with ovarian cancer were retrieved from the database of the National Center of Biotechnology Information, and used as the target markers. The transcriptome of the ovarian tissue of four different tumors, containing tumor presentation and recurrence stages, were sequenced using the Illumina GAII platform. Approximately 85.97% markers were expressed of the total 563 markers, and the majority of them were involved in pathways associated with cancer, signaling and infection. In total, 85 markers were found to be aberrantly expressed in tumor cells from patients with ovarian cancer who had recurrences, including 33 upregulated markers at the recurrence stage. Therefore, they may have roles ovarian tumor due to their aberrant expression. Differentially expressed markers and the associations between them can be assessed by examining the RNA-seq data. These findings may provide novel information for further studies on ovarian cancer.

Ovarian cancer: new developments in clear cell carcinoma and hopes for targeted therapy

Until recently, ovarian clear cell carcinoma was recognized by its unique morphology and unfavorable patient outcome primarily due to tumor chemoresistance. Recently, specific molecular characteristics of ovarian clear cell carcinoma, such as PI3CA mutation, ARID1a mutation and MET amplification, have been elucidated. In addition, an association between endometriosis and the tumor has also been a focus of research in recent years. The aim of this review is to discuss the specificity and importance of molecular changes and various intriguing points that are not solved until today. Finally, future aspects, including hopes for the development of novel therapies, are discussed.

Expressions of fatty acid synthase and HER2 are correlated with poor prognosis of ovarian cancer

The present study was designed to explore the cross talk between fatty acid synthase (FASN) and HER2 (ErbB2) in ovarian cancer. A total of 60 ovarian cancer patients and 15 normal ovarian tissues were enrolled. Tissue array was conducted by using a tissue microarray instrument. Immunohistochemistry was performed to quantify the expressions of HER2 and FASN. The FASN was detected to be distributed in the cell cytoplasm and was significantly correlated with cancer grade (p = 0.000) and FIGO staging (p = 0.000). Patients with FASN overexpression in ovarian cancer tend to have a worse overall survival rate (p = 0.000). HER2 was also stained to be distributed in the cell cytoplasm associated with higher expression in high-grade cancer. It was also disclosed that FASN expression level is not correlated with HER2 status in ovarian cancer. These results for the first time indicated that a cross talk in FASN and HER2 expressions might be associated with prognosis in malignant ovarian cancer.

Cell proliferation and progesterone synthesis depend on lipid metabolism in bovine granulosa cells

In dairy cows, lipids are essential to support energy supplies for all biological functions, especially during early lactation. Lipid metabolism is crucial for sustaining proper reproductive function. Alteration of lipid metabolism impacts follicular development and affects oocyte developmental competence. Indeed, nonesterified fatty acids are able to decrease granulosa cell (GC) proliferation and affect estradiol synthesis, thus potentially affecting follicular growth and viability. The objective of this study was to assess the impact of lipid metabolism on bovine GCs, through the use of the lipid metabolism inhibitors etomoxir, an inhibitor of fatty acid (FA) oxidation through inhibition of carnitine palmitoyl transferase 1 (CPT1), and C75, an inhibitor of FA synthesis through inhibition of fatty acid synthase. We showed that etomoxir and C75 significantly inhibited DNA synthesis in vitro; C75 also significantly decreased progesterone synthesis. Both inhibitors significantly reduced AMPK (5' adenosine monophosphate-activated protein kinase) and acetyl-CoA carboxylase phosphorylation. Etomoxir also affected the AKT (protein kinase B) signaling pathway. Combined, these data suggest that both FA oxidation and synthesis are important for the bovine GCs to express a proliferative and steroidogenic phenotype and, thus, for sustaining follicular growth. Despite these findings, it is important to note that the changes caused by the inhibitors of FA metabolism on GCs in vitro are globally mild, suggesting that lipid metabolism is not as critical in GCs as was observed in the oocyte-cumulus complex. Further studies are needed to investigate the detailed mechanisms by which lipid metabolism interacts with GC functions.

Fatty acid synthase inhibition engages a novel caspase-2 regulatory mechanism to induce ovarian cancer cell death

Blockade of fatty acid synthase (FASN), a key enzyme involved in de novo lipogenesis, results in robust death of ovarian cancer cells. However, known FASN inhibitors have proven to be poor therapeutic agents due to their ability to induce cachexia. Therefore, we sought to identify additional targets in the pathway linking FASN inhibition and cell death whose modulation might kill ovarian cancer cells without the attendant side effects. Here, we show that the initiator caspase-2 is required for robust death of ovarian cancer cells induced by FASN inhibitors. REDD1 (also known as Rtp801 or DDIT4), a known mTOR inhibitor previously implicated in the response to FASN inhibition, is a novel caspase-2 regulator in this pathway. REDD1 induction is compromised in ovarian cancer cells that do not respond to FASN inhibition. Inhibition of FASN induced an ATF4-dependent transcriptional induction of REDD1; downregulation of REDD1 prevented orlistat-induced activation of caspase-2, as monitored by its cleavage, proteolytic activity, and dimerization. Abrogation of REDD1-mediated suppression of mTOR by TSC2 RNAi protected FASN inhibitor-sensitive ovarian cancer cells (OVCA 420 cells) from orlistat-induced death. Conversely, suppression of mTOR with the chemical inhibitors PP242 or rapamycin sensitized DOV13, an ovarian cancer cell line incapable of inducing REDD1, to orlistat-induced cell death through caspase-2. These findings indicate that REDD1 positively controls caspase-2-dependent cell death of ovarian cancer cells by inhibiting mTOR, placing mTOR as a novel upstream regulator of caspase-2 and supporting the possibility of manipulating mTOR to enhance caspase-2 activation in ovarian cancer.

Up-regulated FASN expression promotes transcoelomic metastasis of ovarian cancer cell through epithelial-mesenchymal transition

Fatty acid synthase (FASN), responsible for the de novo synthesis of fatty acids, has been shown to act as an oncogene in various human cancers. However, the mechanisms by which FASN favors the progression of ovarian carcinoma remain unknown. In this study, we evaluated FASN expression in ovarian cancer and investigated how FASN regulates the aggressiveness of ovarian cancer cells. Our results show that increased FASN is associated with the peritoneal metastasis of ovarian cancers. Over-expression of FASN results in a significant increase of tumor burden in peritoneal dissemination, accompanied by augment in cellular colony formation and metastatic ability. Correspondingly, FASN knockdown using RNA interference in ovarian cancer cells inhibits the migration in vitro and experimental peritoneal dissemination in vivo. Mechanistic studies reveal that FASN promotes Epithelial-mesenchymal Transition (EMT) via a transcriptional regulation of E-cadherin and N-cadherin, which is also confirmed by luciferase promoter activity analysis. Taken together, our work demonstrates that FASN promotes the peritoneal dissemination of ovarian cancer cells, at least in part through the induction of EMT. These findings suggest that FASN plays a critical role in the peritoneal metastasis of ovarian cancer. Targeting de novo lipogenesis may have a therapeutic potential for advanced ovarian cancer.

Nac1 interacts with the POZ-domain transcription factor, Miz1

Nac1 (nucleus accumbens 1) is a POZ (poxvirus and zinc finger)-domain transcriptional repressor that is expressed at high levels in ovarian serous carcinoma. Here we identify Nac1 as a novel interacting partner of the POZ-domain transcriptional activator, Miz1 (Myc-interacting zinc-finger protein 1), and using chemical crosslinking we show that this association is mediated by a heterodimeric interaction of the Nac1 and Miz1 POZ domains. Nac1 is found in discrete bodies within the nucleus of mammalian cells, and we demonstrate the relocalization of Miz1 to these structures in transfected HeLa cells. We show that siRNA (small interfering RNA)-mediated knockdown of Nac1 in ovarian cancer cells results in increased levels of the Miz1 target gene product, p21^Cip1. The interaction of Nac1 with Miz1 may thus be relevant to its mechanism of tumourigenesis in ovarian cancer.

Nac1 is a transcriptional repressor that has been implicated in ovarian serous carcinoma. Here we show that Nac1 interacts with the transcription factor Miz1, and suggest that this interaction may contribute to tumourigenesis.

Aberrant lipid metabolism: an emerging diagnostic and therapeutic target in ovarian cancer

Ovarian cancer remains the most lethal gynaecological cancer. A better understanding of the molecular pathogenesis of ovarian cancer is of critical importance to develop early detection tests and identify new therapeutic targets that would increase survival. Cancer cells depend on de novo lipid synthesis for the generation of fatty acids to meet the energy requirements for increased tumour growth. There is increasing evidence that lipid metabolism is deregulated in cancers, including ovarian cancer. The increased expression and activity of lipogenic enzymes is largely responsible for increased lipid synthesis, which is regulated by metabolic and oncogenic signalling pathways. This article reviews the latest knowledge on lipid metabolism and the alterations in the expression of lipogenic enzymes and downstream signalling pathways in ovarian cancer. Current developments for exploiting lipids as biomarkers for the detection of early stage ovarian cancer and therapeutic targets are discussed. Current research targeting lipogenic enzymes and lipids to increase the cytotoxicity of chemotherapy drugs is also highlighted.