UnPAXing the Divergent Roles of PAX2 and PAX8 in High-Grade Serous Ovarian Cancer

Reevaluating the Role of Progesterone in Ovarian Cancer: Is Progesterone Always Protective?

Ovarian cancer (OC) represents a collection of rare but lethal gynecologic cancers where the difficulty of early detection due to an often-subtle range of abdominal symptoms contributes to high fatality rates. With the exception of BRCA1/2 mutation carriers, OC most often manifests as a post-menopausal disease, a time in which the ovaries regress and circulating reproductive hormones diminish. Progesterone is thought to be a "protective" hormone that counters the proliferative actions of estrogen, as can be observed in the uterus or breast. Like other steroid hormone receptor family members, the transcriptional activity of the nuclear progesterone receptor (nPR) may be ligand dependent or independent and is fully integrated with other ubiquitous cell signaling pathways often altered in cancers. Emerging evidence in OC models challenges the singular protective role of progesterone/nPR. Herein, we integrate the historical perspective of progesterone on OC development and progression with exciting new research findings and critical interpretations to help paint a broader picture of the role of progesterone and nPR signaling in OC. We hope to alleviate some of the controversy around the role of progesterone and give insight into the importance of nPR actions in disease progression. A new perspective on the role of progesterone and nPR signaling integration will raise awareness to the complexity of nPRs and nPR-driven gene regulation in OC, help to reveal novel biomarkers, and lend critical knowledge for the development of better therapeutic strategies.

PAX5 and CD70 are expressed in thymic carcinoma but not in atypical thymoma (WHO type B3 thymoma): an immunohistochemical analysis of 60 cases

AIMS

Thymic carcinoma and atypical thymoma (WHO type B3 thymoma) are unusual tumours the separation of which may be challenging in small biopsies. Both tumours consist of epithelioid tumour cells that share similar morphology and immunophenotype with conventional markers. Therefore, additional antibodies are needed to differentiate between these tumours.

METHODS

For this purpose, a panel of immunohistochemical stains including PAX2, PAX5, PAX8 (all monoclonal) and CD70 was used on whole tumour sections of 30 thymic carcinomas and 30 atypical thymomas to determine the expression pattern of these antibodies. In addition, all tumours were stained with markers that are well known to be expressed in both tumours, including pancytokeratin and cytokeratin 5/6. The percentage of positive tumour cells as well as the intensity of staining were evaluated and scored.

RESULTS

PAX5 stained close to 70% of thymic carcinomas while all atypical thymomas were negative for this marker. CD70 was expressed in 18 thymic carcinomas (60%) and in 1 case of atypical thymoma (3%). On the other hand, monoclonal PAX8 was negative in all cases while PAX2 was positive in a single thymic carcinoma. Of the established stains, pancytokeratin and cytokeratin 5/6 were equally positive in both tumours.

CONCLUSIONS

Among the markers explored, only PAX5 and CD70 appear to be differentially expressed and are predominantly restricted to thymic carcinomas. Therefore, in small biopsy specimens and in resections in which the morphological features remain equivocal, application of these particular stains may facilitate separation of thymic carcinoma and atypical thymoma.

Integrated multi-omics analyses reveal Jorunnamycin A as a novel suppressor for muscle-invasive bladder cancer by targeting FASN and TOP1

BACKGROUND

Bladder cancer is a urological carcinoma with high incidence, among which muscle invasive bladder cancer (MIBC) is a malignant carcinoma with high mortality. There is an urgent need to develop new drugs with low toxicity and high efficiency for MIBC because existing medication has defects, such as high toxicity, poor efficacy, and side effects. Jorunnamycin A (JorA), a natural marine compound, has been found to have a high efficiency anticancer effect, but its anticancer function and mechanism on bladder cancer have not been studied.

METHODS

To examine the anticancer effect of JorA on MIBC, Cell Counting Kit 8, EdU staining, and colony formation analyses were performed. Moreover, a xenograft mouse model was used to verify the anticancer effect in vivo. To investigate the pharmacological mechanism of JorA, high-throughput quantitative proteomics, transcriptomics, RT-qPCR, western blotting, immunofluorescence staining, flow cytometry, pulldown assays, and molecular docking were performed.

RESULTS

JorA inhibited the proliferation of MIBC cells, and the IC50 of T24 and UM-UC-3 was 0.054 and 0.084 μM, respectively. JorA-induced significantly changed proteins were enriched in "cancer-related pathways" and "EGFR-related signaling pathways", which mainly manifested by inhibiting cell proliferation and promoting cell apoptosis. Specifically, JorA dampened the DNA synthesis rate, induced phosphatidylserine eversion, and inhibited cell migration. Furthermore, it was discovered that fatty acid synthase (FASN) and topoisomerase 1 (TOP1) are the JorA interaction proteins. Using DockThor software, the 3D docking structures of JorA binding to FASN and TOP1 were obtained (the binding affinities were - 8.153 and - 7.264 kcal/mol, respectively).

CONCLUSIONS

The marine compound JorA was discovered to have a specific inhibitory effect on MIBC, and its potential pharmacological mechanism was revealed for the first time. This discovery makes an important contribution to the development of new high efficiency and low toxicity drugs for bladder cancer therapy.

PAX8 modulates the tumor microenvironment of high grade serous ovarian cancer through changes in the secretome

High grade serous ovarian cancer (HGSC) arises from the fimbriated end of the fallopian tube epithelium (FTE), and in some cases, the ovarian surface epithelium (OSE). PAX8 is a commonly used biomarker for HGSC and is expressed in ∼90% of HGSC. Although the OSE does not express PAX8, murine models of HGSC derived from the OSE acquire PAX8, suggesting that it is not only a marker of Müllerian origin, but also an essential part of cancer progression, potentially from both the OSE and FTE. Previously, we have shown that PAX8 loss in HGSC cells causes tumor cell death and reduces cell migration and invasion. Herein, secretome analysis was performed in PAX8 deleted cells and we identified a reduction of the extracellular matrix (ECM) components, collagen and fibronectin. Immunoblotting and immunofluorescence in PAX8 deleted HGSC cells further validated the results from the secretome analysis. PAX8 loss reduced the amount of secreted TGFbeta, a cytokine that plays a crucial role in remodelling the tumor microenvironment. Furthermore, PAX8 loss reduced the integrity of 3D spheroids and caused a reduction of ECM proteins fibronectin and collagen in 3D cultures. Due to the ubiquitous nature of PAX8 in HGSC, regardless of cell origin, and the association of its reduced expression with decreasing tumor burden, a PAX8 inhibitor could be a promising drug target against various types of HGSC. To accomplish this, we generated a murine oviductal epithelial (MOE) cell line stably expressing PAX8 promoter-luciferase. Using this cell line, we performed a screening assay with a library of FDA-approved drugs (Prestwick Library) and quantitatively assessed these compounds for their inhibition of PAX8. We identified two hits: losartan and captropril, both inhibitors of the renin-angiotensin pathway that inhibit PAX8 expression and function. Overall, this study validates PAX8 as a regulator of ECM deposition in the tumor microenvironment.

PAX8 as a Potential Target for Ovarian Cancer: What We Know so Far

The Fallopian tube epithelium harbors the origin cells for the majority of high-grade serous ovarian carcinomas (HGSCs), the most lethal form of gynecologic malignancies. PAX8 belongs to the paired-box gene family of transcription factors and it is a marker of the FTE secretory cell lineage. Its role has been investigated in migration, invasion, proliferation, cell survival, stem cell maintenance, angiogenesis and tumor growth. In this review, we focus on the pro-tumorigenic role of PAX8 in ovarian cancer; in this context, PAX8 possibly continues to exert its transcriptional activity on its physiological targets but may also function on newly available targets after the tumorigenic hits. Acquiring new insights into the different PAX8 mechanism(s) of action in the tumor microenvironment could uncover new viable therapeutic targets and thus improve the current treatment regimen.

Curcumol Targeting PAX8 Inhibits Ovarian Cancer Cell Migration and Invasion and Increases Chemotherapy Sensitivity of Niraparib

Objective. To investigate the effects of Curcumol on invasion, migration and epithelial-mesenchymal transformation of IGROV-1 and OVCAR-3 cells in ovarian cancer and its potential mechanism. Meanwhile, the effect of Curcumol on the antitumor activity of Niraparib was analyzed. Methods. Cell Counting Kit 8 (CCK-8) was used to detect the effects of Curcumol on the activity of IGROV-1 and OVCAR 3 cells. In vitro invasion assay (Transwell) was used to test the invasiveness of cells. Cell migration was detected by scratch assay. The inhibitory effect of Curcumol on PAX8 was detected by QRT-PCR. To evaluate the antitumor effect of Curcumol in subcutaneous tumor-bearing animal model. Results. Knockdown of PAX8 could inhibit the proliferation, invasion and migration of ovarian cancer cells. After Curcumol treated IGROV-1 and OVCAR-3 cells, the cell proliferation ability was decreased, the number of invasive cells was significantly reduced, and the scratch closure rate was significantly reduced, in a dose-dependent manner. Mechanism studies showed that Curcumol increased the antitumor activity of Niraparib by inhibiting PAX8. Conclusion. Curcumol can inhibit the invasion, migration and epithelial-mesenchymal transformation of IGROV-1 and OVCAR-3 cells in ovarian cancer, and its mechanism is related to the targeted inhibition of PAX8. Curcumol also increased the sensitivity of Niraparib chemotherapy by inhibiting PAX8.

PAX2 induces vascular‑like structures in normal ovarian cells and ovarian cancer

In adult tissue, the paired box 2 (PAX2) protein is expressed in healthy oviductal, but not normal ovarian surface epithelial cells. PAX2 is expressed in a subset of cases of serous ovarian carcinoma; however, the role of PAX2 in the initiation and progression of ovarian cancer remains unknown. The aim of the present study was to determine the biological effects of PAX2 expression in normal and cancerous epithelial cells. By culturing the normal and cancerous ovarian cells that express PAX2 in 3D culture and staining the cells with vasculogenic mimicry markers such as CD31 and PAS, it was shown that PAX2 overexpression in both normal and cancerous ovarian epithelial cells induced formation of vascular-like structures both in vitro and in vivo. These results indicated a potential role of PAX2 in ovarian cancer progression by increasing the presence of vascular-like structures to promote the supply of nutrients to tumor cells and facilitate cancer cell proliferation and invasion.

Maternal tobacco smoke exposure is associated with increased DNA methylation at human metastable epialleles in infant cord blood

Metastable epialleles (MEs) are genomic regions that are stochastically methylated prior to germ layer specification and exhibit high interindividual but low intra-individual variability across tissues. ME methylation is vulnerable to environmental stressors, including diet. Tobacco smoke (TS) exposure during pregnancy is associated with adverse impacts on fetal health and maternal micronutrient levels as well as altered methylation. Our objective was to determine if maternal smoke exposure impacts methylation at MEs. Consistent with prior studies, we observed reductions in one-carbon pathway micronutrients with gestational TS exposure, including maternal folate (P = 0.02) and vitamins B6 (P = 0.05) and B12 (P = 0.007). We examined putative MEs BOLA3, PAX8, and ZFYVE28 in cord blood specimens from 85 Newborn Epigenetics STudy participants. Gestational TS exposure was associated with elevated DNA methylation at PAX8 (+5.22% average methylation; 95% CI: 0.33% to 10.10%; P = 0.037). In human conceptal kidney tissues, higher PAX8 transcription was associated with lower methylation (R s = 0.55; P = 0.07), suggesting that the methylation levels established at MEs, and their environmentally induced perturbation, may have meaningful, tissue-specific functional consequences. This may be particularly important because PAX8 is implicated in several cancers, including pediatric kidney cancer. Our data are the first to indicate vulnerability of human ME methylation establishment to TS exposure, with a general trend of increasing levels of methylation at these loci. Further investigation is needed to determine how TS exposure-mediated changes in DNA methylation at MEs, and consequent expression levels, might affect smoking-related disease risk.

Does the "Devil" originate from the fallopian tubes?

Epithelial ovarian cancer (OC) is a heterogeneous disease and continues to be mostly diagnosed in advanced stages. The high lethality, the high rate of platinum-resistance, and the poor survival outcomes are the principal factors for categorizing OC among the most aggressive gynecological cancers. Only recently, a substantial progress has been made in our latest understanding of the origins of OC, particularly of high-grade serous histology. For a long time, the accumulation of genetic alterations in epithelial single layer cells of ovarian cysts caused by cyclic ovulations was considered as the most important driver and the long-standing dogma of ovarian tumorigenesis. Besides, the unique biological features and high histological heterogeneity of OC did not support this hypothesis. Indeed, various extra-ovarian cells of origin and multiple sites to each histotype were proposed, supported by cogent evidence from clinical cohorts and animal studies. In light of this enigma, this review was conducted to discuss the recent evidence supporting the revised origins of ovarian carcinoma histotypes with a particular focus on high-grade serous OC which may impact diagnostic and preventive approaches.

Paired-Box Gene 8 (PAX8) and Its Association With Epithelial Carcinomas

Cancer is the second most common culprit of mortality in the United States and epithelial carcinomas are considered as one of the most predominant types of cancer. The association between epithelial cancers and paired-box gene 8 (PAX8) has been studied significantly before. PAX8 belongs to the paired-box gene family, which plays an important role in the organogenesis of different body organ systems, especially the thyroid gland, the renal system, and the Müllerian system. Immunohistochemical staining is being used to detect PAX8 expression in different epithelial cancers and differentiate them from PAX8-negative tumors. In follicular, papillary, and anaplastic thyroid carcinomas, targeting the PAX8/peroxisome proliferator-activated receptors (PPARs) fusion protein is being considered as a potential mechanism for therapy. Moreover, because of its high expression in primary ovarian cancers, PAX8 is being considered as a target for ovarian cancer treatment as well. More studies are needed to test the possibility of using PAX8 as a possible target for managing endometrial carcinomas. In this article, we review the functions of the PAX8 gene, how its mutations lead to the development of certain epithelial carcinomas, how it can be used as a diagnostic or a prognostic marker, and its potential as a therapeutic target for these cancers.

Incidence of malignant transformation in the oviductal fimbria in laying hens, a preclinical model of spontaneous ovarian cancer

Ovarian high grade serous carcinoma (HGSC) is a lethal form of ovarian cancer (OVCA). In most cases it is detected at late stages as the symptoms are non-specific during early stages. Emerging information suggests that the oviductal fimbria is a site of origin of ovarian HGSC. Currently available tests cannot detect ovarian HGSC at early stage. The lack of a preclinical model with oviductal fimbria that develops spontaneous ovarian HGSC is a significant barrier to developing an early detection test for this disease. The goal of this study was to examine if the oviductal fimbria in hens is a site of origin of HGSC and whether it expresses several putative markers expressed in ovarian HGSC in patients. A total of 135 laying hens (4 years old) were selected from a flock using transvaginal ultrasound (TVUS) imaging, followed by euthanasia and gross examination for the presence of solid masses and ascites. Histological types of carcinomas were determined by hematoxylin and eosin staining. Expression of WT-1, mutant p53, CA-125, PAX2 and Ki67 in normal or malignant fimbriae or ovaries were examined using immunohistochemistry, immunoblotting and gene expression assays. This study detected tumors in oviductal fimbriae in hens and routine staining revealed ovarian HGSC-like microscopic features in these tumors. These tumors showed similarities to ovarian HGSC in patients in expressing several markers. Compared with normal fimbriae, intensities of expression of WT-1, mutant p53, CA-125, and Ki67 were significantly (P<0.05) higher in fimbrial tumors. In contrast, expression of PAX2 decreased gradually as the tumor progressed to late stages. The patterns of expression of these markers were similar to those in ovarian HGSC patients. Thus, tumors of the oviductal fimbria in hens may offer a preclinical model to study different aspects of spontaneous ovarian HGSC in women including its early detection.

Fallopian Tube-Derived Tumor Cells Induce Testosterone Secretion from the Ovary, Increasing Epithelial Proliferation and Invasion

The fallopian tube epithelium is the site of origin for a majority of high grade serous ovarian carcinomas (HGSOC). The chemical communication between the fallopian tube and the ovary in the development of HGSOC from the fallopian tube is of interest since the fimbriated ends in proximity of the ovary harbor serous tubal intraepithelial carcinoma (STICs). Epidemiological data indicates that androgens play a role in ovarian carcinogenesis; however, the oncogenic impact of androgen exposure on the fallopian tube, or tubal neoplastic precursor lesions, has yet to be explored. In this report, imaging mass spectrometry identified that testosterone is produced by the ovary when exposed to tumorigenic fallopian tube derived PTEN deficient cells. Androgen exposure increased cellular viability, proliferation, and invasion of murine cell models of healthy fallopian tube epithelium and PAX2 deficient models of the preneoplastic secretory cell outgrowths (SCOUTs). Proliferation and invasion induced by androgen was reversed by co-treatment with androgen receptor (AR) antagonist, bicalutamide. Furthermore, ablation of phosphorylated ERK reversed proliferation, but not invasion. Investigation of two hyperandrogenic rodent models of polycystic ovarian syndrome revealed that peripheral administration of androgens does not induce fallopian proliferation in vivo. These data suggest that tumorigenic lesions in the fallopian tube may induce an androgenic microenvironment proximal to the ovary, which may in turn promote proliferation of the fallopian tube epithelium and preneoplastic lesions.

Histomorphology and Immunohistochemistry of a Congenital Nephromegaly Demonstrate Concurrent Features of Heritable and Acquired Cystic Nephropathies in a Girgentana Goat (Capra falconeri)

Polycystic kidney diseases (PKD) represent frequent congenital and adult nephropathies in humans and domestic animals. This report illustrates an uncommon state of congenital PKD in a girgentana goat (Capra falconeri). A stillborn female goat kid was submitted for postmortem examination and underwent macroscopic and microscopic examination. The kidneys showed a bilateral nephromegaly and a perpendicular polycystic altered texture of the renal parenchyma. Renal tissue sections were comprehensively investigated by histopathology (overview and special stains), immunohistochemistry (CD10, CD117, pan-cytokeratin, cytokeratin 7, E-cadherin, Pax2, Pax8, and vimentin), and electron microscopy (SEM, TEM). Histopathology of renal tissue sections revealed polycystic alterations of the renal parenchyma as well as conspicuous polypoid proliferates/projections of the renal tubular epithelium, which showed clear cell characteristics. Furthermore, epithelial projections were indicative for epithelio-mesenchymal-transition, cellular depolarization, and strong expression of differentiation markers Pax2, Pax8, and CD10. Ultrastructural morphology of the projections was characterized by numerous diffusely distributed, demarked round cytoplasmic structures and several apico-lateral differentiations. Additionally, hepatic malformations comprising biliary duct proliferation with saccular dilation and bridging fibrosis were observed. Notably, this report describes the first case of a congenital cystic nephropathy with overlapping features of heritable and acquired nephropathies in any species. Epithelio-mesenchymal-transition and altered cadherin expression seem to be crucial components of a suspected pathomechanism during cystogenesis.

Oncogenes in high grade serous adenocarcinoma of the ovary

High grade serous ovarian cancer is characterized by relatively few mutations occurring at low frequency, except in TP53. However other genetic aberrations such as copy number variation alter numerous oncogenes and tumor suppressor genes. Oncogenes are positive regulators of tumorigenesis and play a critical role in cancer cell growth, proliferation, and survival. Accumulating evidence suggests that they are crucial for the development and the progression of high grade serous ovarian carcinoma (HGSOC). Though many oncogenes have been identified, no successful inhibitors targeting these molecules and their associated pathways are available. This review discusses oncogenes that have been identified recently in HGSOC using different screening strategies. All the genes discussed in this review have been functionally characterized both in vitro and in vivo and some of them are able to transform immortalized ovarian surface epithelial and fallopian tube cells upon overexpression. However, it is necessary to delineate the molecular pathways affected by these oncogenes for the development of therapeutic strategies.

Kelch-like protein 14 promotes proliferation and migration of ovarian cancer cells

Kelch-like protein 14 (KLHL14) belongs to the Kelch gene family, which interacts with TorsinA and is associated with dystonia symptoms. However, the effect of KLHL14 on tumorigenesis remains unclear; thus, we aimed to explore the effects of KLHL14 on ovarian cancer cells. By analyzing information regarding ovarian cancer patients obtained from The Cancer Genome Atlas (TCGA)-Ovarian Cancer Database, we found that the KLHL14 gene is highly expressed in ovarian cancer, and patients with high KLHL14 expression had lower survival than those with low expression. qRT-PCR and western blot results revealed that the mRNA and protein levels of KLHL14 in ovarian cancer cells were higher in A-2780 cells than in KGN cells. After constructing cell lines with a knocked down KLHL14 gene, we used the MTT assay, flow cytometry with propidium iodide (PI), Annexin V-FITC/PI, and transwell assay and found that knockdown of KLHL14 gene inhibited proliferation of A-2780 cells, caused cell G0/G1 phase arrest, promoted apoptosis, and inhibited migration and invasiveness. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that KLHL14 may promote development of ovarian cancer by regulating signaling pathways such as mTOR, WNT, and TGF-beta. In short, the KLHL14 gene plays an important role in ovarian cancer development and may be a target for ovarian cancer detection and treatment.

Transcription factors in epithelial ovarian cancer: histotype-specific drivers and novel therapeutic targets

Transcription factors (TFs) are major contributors to cancer risk and somatic development. In preclinical and clinical studies, direct or indirect inhibition of TF-mediated oncogenic gene expression profiles have proven to be effective in many tumor types, highlighting this group of proteins as valuable therapeutic targets. In spite of this, our understanding of TFs in epithelial ovarian cancer (EOC) is relatively limited. EOC is a heterogeneous disease composed of five major histologic subtypes; high-grade serous, low-grade serous, endometrioid, clear cell and mucinous. Each histology is associated with unique clinical etiologies, sensitivity to therapies, and molecular signatures - including diverse transcriptional regulatory programs. While some TFs are shared across EOC subtypes, a set of TFs are expressed in a histotype-specific manner and likely explain part of the histologic diversity of EOC subtypes. Targeting TFs present with unique opportunities for development of novel precision medicine strategies for ovarian cancer. This article reviews the critical TFs in EOC subtypes and highlights the potential of exploiting TFs as biomarkers and therapeutic targets.

A cell-of-origin epigenetic tracer reveals clinically distinct subtypes of high-grade serous ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (HGSOC) is a major unmet need in oncology. The remaining uncertainty on its originating tissue has hampered the discovery of molecular oncogenic pathways and the development of effective therapies.

METHODS

We used an approach based on the retention in tumors of a DNA methylation trace (OriPrint) that distinguishes the two putative tissues of origin of HGSOC, the fimbrial (FI) and ovarian surface epithelia (OSE), to stratify HGSOC by several clustering methods, both linear and non-linear. The identified tumor subtypes (FI-like and OSE-like HGSOC) were investigated at the RNAseq level to stratify an in-house cohort of macrodissected HGSOC FFPE samples to derive overall and disease-free survival and identify specific transcriptional alterations of the two tumor subtypes, both by classical differential expression and weighted correlation network analysis. We translated our strategy to published datasets and verified the co-occurrence of previously described molecular classification of HGSOC. We performed cytokine analysis coupled to immune phenotyping to verify alterations in the immune compartment associated with HGSOC. We identified genes that are both differentially expressed and methylated in the two tumor subtypes, concentrating on PAX8 as a bona fide marker of FI-like HGSOC.

RESULTS

We show that: - OriPrint is a robust DNA methylation tracer that exposes the tissue of origin of HGSOC. - The tissue of origin of HGSOC is the main determinant of DNA methylation variance in HGSOC. - The tissue of origin is a prognostic factor for HGSOC patients. - FI-like and OSE-like HGSOC are endowed with specific transcriptional alterations that impact patients' prognosis. - OSE-like tumors present a more invasive and immunomodulatory phenotype, compatible with its worse prognostic impact. - Among genes that are differentially expressed and regulated in FI-like and OSE-like HGSOC, PAX8 is a bona fide marker of FI-like tumors.

CONCLUSIONS

Through an integrated approach, our work demonstrates that both FI and OSE are possible origins for human HGSOC, whose derived subtypes are both molecularly and clinically distinct. These results will help define a new roadmap towards rational, subtype-specific therapeutic inroads and improved patients' care.

Reduced PAX2 expression in murine fallopian tube cells enhances estrogen receptor signaling

High-grade serous ovarian cancer (HGSOC) is thought to progress from a series of precursor lesions in the fallopian tube epithelium (FTE). One of the preneoplastic lesions found in the FTE is called a secretory cell outgrowth (SCOUT), which is partially defined by a loss of paired box 2 (PAX2). In the present study, we developed PAX2-deficient murine cell lines in order to model a SCOUT and to explore the role of PAX2 loss in the etiology of HGSOC. Loss of PAX2 alone in the murine oviductal epithelium (MOE) did not induce changes in proliferation, migration and survival in hypoxia or contribute to resistance to first line therapies, such as cisplatin or paclitaxel. RNA sequencing of MOE PAX2shRNA cells revealed significant alterations in the transcriptome. Silencing of PAX2 in MOE cells produced a messenger RNA expression pattern that recapitulated several aspects of the transcriptome of previously characterized human SCOUTs. RNA-seq analysis and subsequent qPCR validation of this SCOUT model revealed an enrichment of genes involved in estrogen signaling and an increase in expression of estrogen receptor α. MOE PAX2shRNA cells had higher estrogen signaling activity and higher expression of putative estrogen responsive genes both in the presence and absence of exogenous estrogen. In summary, loss of PAX2 in MOE cells is sufficient to transcriptionally recapitulate a human SCOUT, and this model revealed an enrichment of estrogen signaling as a possible route for tumor progression of precursor lesions in the fallopian tube.

Developing Organoids from Ovarian Cancer as Experimental and Preclinical Models

Ovarian cancer (OC) represents the most dismal gynecological cancer. Pathobiology is poorly understood, mainly due to lack of appropriate study models. Organoids, defined as self-developing three-dimensional in vitro reconstructions of tissues, provide powerful tools to model human diseases. Here, we established organoid cultures from patient-derived OC, in particular from the most prevalent high-grade serous OC (HGSOC). Testing multiple culture medium components identified neuregulin-1 (NRG1) as key factor in maximizing OC organoid development and growth, although overall derivation efficiency remained moderate (36% for HGSOC patients, 44% for all patients together). Established organoid lines showed patient tumor-dependent morphology and disease characteristics, and recapitulated the parent tumor's marker expression and mutational landscape. Moreover, the organoids displayed tumor-specific sensitivity to clinical HGSOC chemotherapeutic drugs. Patient-derived OC organoids provide powerful tools for the study of the cancer's pathobiology (such as importance of the NRG1/ERBB pathway) as well as advanced preclinical tools for (personalized) drug screening and discovery.

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Organoids are established from ovarian cancer (OC)

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Neuregulin-1 (NRG1) is identified as key component for OC organoid growth

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OC organoids capture disease hallmarks and recapitulate patient tumor characteristics

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OC organoids are amenable to drug screening and mechanistic (NRG1/ERBB) research

Exosomal MiR-744 Inhibits Proliferation and Sorafenib Chemoresistance in Hepatocellular Carcinoma by Targeting PAX2

BACKGROUND Hepatocellular carcinoma (HCC) is a commonly occurring liver malignancy. Its prognosis remains unsatisfactory. Accumulating evidence has revealed that exosomal microRNAs (miRNAs) act as biomarkers and play crucial roles in the advancement of HCC. The current study explored the biological role and fundamental mechanism of exosomal miR-744 in HCC. MATERIAL AND METHODS The serum exosomes of HCC patients were isolated by differential ultracentrifugation. MiR-744 expression in HCC tissues, cell lines and serum exosomes were detected by quantitative real-time polymerase chain reaction (qRT-PCR). EdU (5-ethynyl-2'-deoxyuridine) assay and Cell Counting Kit-8 (CCK-8) assay were conducted to show the impacts of miR-744 or exosomal miR-744 on proliferation and sorafenib resistance in HepG2 cells. The target of miR-744 was ascertained by regulating the level of miR-744 in HepG2 cells. RESULTS MiR-744 is downregulated in HCC tissues and cell lines as well as in exosomes derived from patient serum and HepG2 cells. Additionally, downregulated miR-744 promotes HepG2 cell proliferation and inhibits the chemosensitivity of HepG2 cells to sorafenib. PAX2 was identified as the functional target of miR-744. Interestingly, miR-744 is decreased in exosomes derived from sorafenib-resistant HepG2 cells. Furthermore, when treated with the miR-744-enriched exosomes, the proliferation of HepG2 cells was significantly suppressed, and the sorafenib resistance was reduced. CONCLUSIONS MiR-744 has an imperative role in the propagation and chemoresistance of HCC. Serum exosomal miR-744 might act as a biomarker of HCC, and exosomal miR-744 might offer an innovative strategy for HCC treatment.

Pseudolaric acid B inhibits PAX2 expression through Wnt signaling and induces BAX expression, therefore promoting apoptosis in HeLa cervical cancer cells

Objectives

Pseudolaric acid B (PAB) has been shown to inhibit the growth of various tumor cells, but the molecular details of its function are still unknown. This study investigated the molecular mechanisms by which PAB induces apoptosis in HeLa cells.

Methods

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to investigate the effect of PAB treatment in various cervical cancer cell lines. Annexin V/propidium iodide staining combined with flow cytometry and Hoechst 33258 staining were used to assess PAB-induced apoptosis. Additionally, we performed bioinformatics analyses and identified a paired box 2 (PAX2) binding site on the BAX promoter. We then validated the binding using luciferase and chromatin immunoprecipitation assays. Finally, western blotting assays were used to investigate PAB effect on the Wnt signaling and the involved signaling molecules.

Results

PAB promotes apoptosis and downregulates PAX2 expression in HeLa cells in a time- and concentration-dependent manner. PAX2 binds to the promoter of BAX and inhibits its expression; therefore, PAX2 inhibition is associated with increased levels of BAX, which induces apoptosis of HeLa cells via the mitochondrial pathway. Additionally, PAB inhibits classical Wnt signaling.

Conclusion

PAB effectively inhibits Wnt signaling and PAX2 expression, and increases BAX levels, which induce apoptosis in HeLa cells. Therefore, PAB is a promising natural molecule for the treatment of cervical cancer.