Oviductal Epithelium Research Articles

A putative role for ALDH inhibitors and chemoprevention of BRCA-mutation-driven tumors

Aldehyde dehydrogenase (ALDH) enzymatic activity is a marker of cancer-initiating cells (CIC) in many tumor types. Our group and others have found that ALDH1A family inhibitors (ALDHi) can preferentially induce death of ovarian CIC in established ovarian cancer. We sought to determine if ALDHi, by targeting CIC at the time of tumor initiation, could function as a chemopreventive for ovarian cancer. As BRCA1/2 mutation carriers represent a population who could benefit from an ovarian cancer chemopreventive, we focused on BRCA mutation-associated tumor cell lines and murine tumor models. We found that, compared to BRCA wild-type cells, BRCA mutant ovarian cancer cells are more sensitive to the ALDHi673A. Similarly, while 673A treatment of wild-type fallopian tube epithelial (FTE) cells is non-toxic, 673A induces death in FTE cells with BRCA1 knockdown. Using a murine fallopian tube organoid model of ovarian carcinogenesis, we show that 673A reduced organoid complexity and significantly reduce colony formation of BRCA-mutant cells. Organoids that persisted after 673A treatment were predominantly BRCA1wt, but NF1 mutant, suggesting a resistance mechanism. Finally, using the BPRN (Brca1, Trp53, Rb1, Nf1 inactivated) mouse model of tubo-ovarian cancer, we evaluated the impact of intermittent 673A therapy on carcinogenesis. 673A treatment resulted in a significant reduction in serous tubal intraepithelial carcinoma (STIC) lesions and carcinomas. Collectively, the findings suggest that ALDHi, such as 673A, could serve as chemopreventive agents for BRCA1/2 mutation carriers.

How the Oviduct Lipidomic Profile Changes over Time after the Start of an Obesogenic Diet in an Outbred Mouse Model.

We investigated whether a high-fat/high-sugar (HF/HS) diet alters the lipidomic profile of the oviductal epithelium (OE) and studied the patterns of these changes over time. Female outbred Swiss mice were fed either a control (10% fat) or HF/HS (60% fat, 20% fructose) diet. Mice (n = 3 per treatment per time point) were sacrificed and oviducts were collected at 3 days and 1, 4, 8, 12 and 16 weeks on the diet. Lipids in the OE were imaged using matrix-assisted laser desorption ionisation mass spectrometry imaging. Discriminative m/z values and differentially regulated lipids were determined in the HF/HS versus control OEs at each time point. Feeding the obesogenic diet resulted in acute changes in the lipid profile in the OE already after 3 days, and thus even before the development of an obese phenotype. The changes in the lipid profile of the OE progressively increased and became more persistent after long-term HF/HS diet feeding. Functional annotation revealed a differential abundance of phospholipids, sphingomyelins and lysophospholipids in particular. These alterations appear to be not only caused by the direct accumulation of the excess circulating dietary fat but also a reduction in the de novo synthesis of several lipid classes, due to oxidative stress and endoplasmic reticulum dysfunction. The described diet-induced lipidomic changes suggest alterations in the OE functions and the oviductal microenvironment which may impact crucial reproductive events that take place in the oviduct, such as fertilization and early embryo development.

Dysregulation of TMEM16A impairs oviductal transport of embryos.

Ectopic pregnancy is an acute abdominalgia in obstetrics and gynecology, especially in fallopian tubal pregnancy. The ion channel protein transmembrane protein 16A (TMEM16A) is widely distributed in various tissues, even in the oviduct. In this study, we showed that TMEM16A was expressed in the human fallopian tube and was upregulated in patients with tubal pregnancy. By measuring isolated fallopian tube tissues, we found that TMEM16A was involved in regulating not only the contraction of muscle strips but also the beat frequency of cilia. In addition, pharmacological activation or inhibition of TMEM16A could lead to retention of embryos in oviducts. Moreover, the embryos in oviducts were delayed in development and some of them had malformations and deletions. The total number of embryos in the oviducts and uterus was significantly less than that of the control group. Furthermore, we detected changes in the level of m6A methylation, where the relevant writers and readers were reduced in tubal tissues from tubal pregnancies. In m6A mRNA methylation, writers catalyze the addition of methyl groups to cytosine residues and readers bind to the methyl groups and affect gene translation. In human fallopian tube epithelial cell line FTE187, we found that interference with methyltransferase 3 (METTL3) expression increased TMEM16A, suggesting that TMEM16A might be regulated by m6A methylation. In general, our study revealed a novel regulatory point for embryo transport and development, introducing a new role for the diagnosis and treatment of tubal pregnancy.NEW & NOTEWORTHY The ion channel protein TMEM16A is expressed in the epithelium and smooth muscle of the human fallopian tube and is upregulated in patients with tubal pregnancy. TMEM16A is involved in regulating the smooth muscle contraction and the cilia beating. Dysregulated TMEM16A may result in embryo retention in the oviduct and delayed early embryo development. Our study reveals a new regulatory point for embryo transport and development.

Exosomal microRNAs in tubal fluid may be involved in damage to tubal reproductive function associated with tubal endometriosis

Research questionWhat is the effect of tubal endometriosis on tubal epithelial ultrastructure and is there a differential expression of exosomal microRNAs (miRNAs) in tubal fluid which may affect tubal infertility? DesignHuman fallopian tube epithelium and tubal fluid samples were obtained from patients with and without tubal endometriosis. Scanning electron microscopy and transmission electron microscopy were used to assess ultrastructural changes. Exosomal miRNAs in tubal fluid were extracted for microarray. ResultsEpithelial damage was visualized in the tubal endometriosis group using electron microscopy. The number of organelles decreased (P = 0.0314), and organelle structure was destroyed. A total of 14 differentially expressed exosomal miRNAs were detected in tubal fluid (fold change >2 and P < 0.05). Four miRNAs (miR-1273f, miR-5699-5p, miR-6087 and miR-6747-5p) were validated by quantitative real-time polymerase chain reaction. Bioinformatic analysis showed that most of the target genes participated in embryo transport, regulation of cell communication, anatomical structure morphogenesis and immune system processes. ConclusionsTubal endometriosis results in damage to the tubal epithelial ultrastructure in human specimens and the presence of differentially expressed exosomal miRNAs in tubal liquid. These findings help to clarify the pathogenesis of tubal endometriosis-associated infertility and the mechanisms driving tubal epithelial ultrastructure damage in tubal endometriosis.

P-103 Three-dimensional oviductal organoid model to study spermatozoa-oviduct interaction in humans

Abstract Study question Is it possible to establish an in vitro model that recapitulating human oviduct to investigate sperm-oviduct interaction Summary answer Three-dimensional (3D) oviductal organoid model was established from either primary human oviductal tissues or immortalized human OE-E6/67 cell line, based on our protocol. What is known already The sperm reservoir in oviduct is formed to maintain the fertilizing capacity of spermatozoa until ovulation by the binding of sperm to the epithelial lining of the oviduct, which is also significant to select sperm with normal chromatin structure and superior fertilization ability. The regulation and mechanism of sperm reservoir formation in human is still unknown, mainly due to the ethical issue and technical difficulty in obtaining enough human oviduct. We previously demonstrated that sperm fucosyltransferase-5 (sFUT5), a carbohydrate-binding protein on spermatozoa, is responsible for spermatozoa-oviduct interaction in humans. Study design, size, duration Human oviductal epithelial cell line immortalized by HPV 16 E6/E7 open reading frame by retroviral expression system was employed to establish the co-culture model. Fresh human samples (human spermatozoa,N = 30; 1-2 cm primary oviductal tissue,N = 15) were collected in hospital with signed consent. Fluorescent pre-labelled sperm were co-cultured with organoids for 2 hours. At least three replicates were conducted for each assay. Participants/materials, setting, methods Morphological characterization and markers expressions of the organoid were determined by immunohistochemistry and confocal microscopy analysis. The sperm binding capacity of the oviductal organoid was studied by co-culture system. Sperm chromatin structure of the organoid-bound sperm was assessed by flow cytometry-based TUNEL assay. Affinity chromatography followed by nano-liquid chromatography–mass spectrometry was used to identify the sFUT5-binding proteins on ovidutal epithelial cells (OECs) and their expressions on OECs were validated by immunostaining/flow cytometry. Main results and the role of chance The organoid exhibited a hollow structure surrounded by a single layer of OECs. Immunohistochemistry analysis revealed the high expressions of epithelial marker E-cadherin (basolateral membrane), secretory marker pair-box 8 (PAX8) and proliferative marker Ki67. Expression of ciliated cell marker, acetylated tubulin (AcTUB) can also be detected. The modification of culture environment successfully reversed the OEC organoids polarity as demonstrated by immunostaining using antibodies against ZO-1 (apical marker) and E-cadherin (basolateral marker), making the organoid accessible during the co-culture. These apical-out OEC organoids have significantly higher sperm binding capacities than their basal-out counterparts. Furthermore, OEC organoid-bound spermatozoa possessed more intact DNA than the unbound spermatozoa. The results indicate the relevance of using OEC organoid-spermatozoa co-culture model as a tool to assess spermatozoa-oviduct interaction in humans. By using immuno-affinity chromatography and mass spectrometry analysis, cell adhesion molecule 4 (CADM4) was then identified as a potential sFUT5-interacting protein on OECs. This result was further supported by flow cytometry and immunofluorescent staining. 3-D oviductal organoid model demonstrates profound potential for in vitro investigation of human oviduct physiology. Limitations, reasons for caution Our 3D model may not fully represent the entire cellular complexity and tubular architecture of the oviductal epithelium. Further investigation on the sperm morphology and DNA integrity and analysis on organoid transcriptome will enhance our understanding on oviduct in human reproduction. Wider implications of the findings The results from co-culture may give a clue to future study on whether oviductal organoid can be applied clinically for functional sperm selection in in vitro fertilization. Our apical-out organoid model may also be applied to study tubal ectopic pregnency. Trial registration number not applicable

Inducing ciliation in equine oviduct epithelial cell monolayers

Recently, we developed re-differentiated equine oviduct epithelial cell (EOEC) monolayers in Transwell inserts. EOEC monolayers demonstrated various in vivo-like morphological characteristics, but often lacked secondary cilia. The monolayers were classified as low (<1% secondary cilia) or high (>5% secondary cilia) spontaneously re-differentiated, with the latter in the minority (5-10%). Interestingly, only high re-differentiated monolayers responded to Notch inhibition by developing in vivo-like secondary ciliation rates, i.e. over 50% ciliated cells. In this study, we aimed to consistently generate high re-differentiated monolayers. We first assessed whether secondary cilia formation was affected by donor mare, cycle stage and/or experiment. For this, harvested oviduct explants were cultured for 10 days at a concentration of 10 × 106 EOECs per 9.6 cm² well, to yield a confluent de-differentiated monolayer in conventional wells. Subsequently, the monolayers were trypsinized and the EOECs were reseeded onto the microporous membrane of hanging inserts at a concentration of 0.3 × 105 EOECs per 0.33 cm² insert. Three days after seeding, the EOECs were triggered to re-differentiate by air-liquid interface introduction (ALI). After 1 and 2 months in culture, EOEC monolayers were fixed and their phenotype was assessed by combined immunofluorescence staining to detect cilia (mouse anti-acetylated α-tubulin antibody; Alexa 488-conjugated goat anti-mouse secondary antibody),cell nuclei (Hoechst 33342) and actin filaments (Alexa 568-conjugated phalloidin). Neither cell donor nor cycle stage had any effect on secondary ciliation rates, whereas experimental modifications did. In 3/15 experiments, >95% of the monolayers demonstrated high re-differentiated monolayers. To discover the source of experimental variation, the seeding concentration of the de-differentiated EOECs was varied between 0.1 and 10 × 105 EOECs per 0.33 cm² insert; this did not affect secondary ciliation rates. In a third experiment, the effect of varying the seeding concentration of the harvested oviduct explant EOECs used to establish the de-differentiated monolayers, between 1 and 30 × 106 EOECs per 9.6 cm² well, was evaluated. EOECs harvested from de-differentiated monolayers 10 days after oviduct explant seeding at 1 or 5 × 106 EOECs per well supported the formation of high re-differentiated monolayers in >95% of cases. Within 1 month after ALI, >50% and >30% of the re-differentiated EOECs showed secondary cilia after initial seeding of 1 and 5 × 106 oviduct explant EOECs per well, respectively. Notch-inhibition helped to further increase secondary ciliation rates to >70% in the re-differentiated monolayers. We conclude that initial oviduct explant EOEC seeding concentration is critical to subsequently generating monolayers that closely resemble in vivo oviduct epithelia.

Buffalo sperm membrane glycan-binding proteins reveal precise and preferential binding signatures with specific glycans targets on oviduct epithelium and zona pellucida-an implication in fertilization

Sperm membrane glycan-binding proteins (lectins) interact with the counterpart glycans in the oviduct, oocytes, and vice-versa. It has already been well known that specific glycans are present on oviductal epithelium and zona pellucida (ZP) in different mammalian species. Some of these glycans are necessary for oviductal sperm reservoir formation and gamete recognition. The specific binding phenomenon of lectin-glycans is one of the vital factors for successful fertilization in mammals. We hypothesized that buffalo sperm membrane glycan-binding proteins have specific glycan targets in the oviduct and ZP supporting the fertilization event. In the present investigation, sperm membrane proteins were extracted and assessed for their binding capacity with glycans using a high-throughput glycan microarray. The most promising glycan binding signals were evaluated to confirm the sperm putative receptors for glycan targets in the oviductal epithelial cells (OEC) and on ZP using an in-vitro competitive binding inhibition assay. Based on an array of 100 glycans, we found that N-acetyllactosamine (LacNAc), Lewis-a trisaccharide, 3′-sialyllactosamine and LacdiNAc were the most promising glycans and selected for further in-vitro validation. We established an inhibitory concentration of 12 mM Lewis-a trisaccharide and 10 μg/ml Lotus tetragonolobus (LTL) lectin for the sperm-OEC binding interaction, indicating its specificity and sensitivity. We observed that 3 mM 3′-sialyllactosamine, and LacdiNAc were the most competitive inhibitory concentration in sperm-ZP binding, suggesting a specific and abundance-dependent binding affinity. The competitive binding affinity of Maackia amurensis (MAA) lectin with Neu5Ac(α2-3)Gal(β1-4)GlcNAc further supports the abundance of 3′-sialyllactosamine on ZP responsible for sperm binding. Our findings develop the strong evidence on buffalo sperm putative receptors underlying their locking specificities with Lewis-a trisaccharide in oviduct and 3′-sialyllactosamine on ZP. The functional interaction of buffalo sperm lectins with the target glycans in OEC and ZP appears to be accomplished in an abundance-dependent manner, facilitating the fertilization event in buffaloes.

Label-Free Quantification Mass Spectrometry Identifies Protein Markers of Chemotherapy Response in High-Grade Serous Ovarian Cancer

Eighty percent of ovarian cancer patients initially respond to chemotherapy, but the majority eventually experience a relapse and die from the disease with acquired chemoresistance. In addition, 20% of patients do not respond to treatment at all, as their disease is intrinsically chemotherapy resistant. Data-independent acquisition nano-flow liquid chromatography-mass spectrometry (DIA LC-MS) identified the three protein markers: gelsolin (GSN), calmodulin (CALM1), and thioredoxin (TXN), to be elevated in high-grade serous ovarian cancer (HGSOC) tissues from patients that responded to chemotherapy compared to those who did not; the differential expression of the three protein markers was confirmed by immunohistochemistry. Analysis of the online GENT2 database showed that mRNA levels of GSN, CALM1, and TXN were decreased in HGSOC compared to fallopian tube epithelium. Elevated levels of GSN and TXN mRNA expression correlated with increased overall and progression-free survival, respectively, in a Kaplan-Meier analysis of a large online repository of HGSOC patient data. Importantly, differential expression of the three protein markers was further confirmed when comparing parental OVCAR-5 cells to carboplatin-resistant OVCAR-5 cells using DIA LC-MS analysis. Our findings suggest that GSN, CALM1, and TXN may be useful biomarkers for predicting chemotherapy response and understanding the mechanisms of chemotherapy resistance. Proteomic data are available via ProteomeXchange with identifier PXD033785.

Abstract 152: Robust establishment and expansion of human fallopian tube organoids in serum-free culture

Abstract High-grade serous ovarian cancer (HGSOC) is the most prevalent subtype of epithelial ovarian cancer. Despite its name, HGSOC originates in the fallopian tube (FT), but metastasizes quickly in the adnexal region and is the most lethal gynecological cancer worldwide. Organoid culture is emerging as a powerful model for studying normal FT cell biology and ovarian cancer. To standardize primary human FT and HGSOC organoid culture, we have developed GyneCult Fallopian Tube Organoid Medium (FTOM), an optimized serum-free medium and a workflow that supports robust and representative FT organoid culture from freshly isolated or cryopreserved primary human FT cells. FT cultures were initiated by seeding 4000 dissociated single cells directly into 20 µL Corning® Matrigel® domes and overlaying them with FT Organoid Medium. After seeding, cultures were maintained with full-medium changes every 3 - 4 days and were split either in a passage ratio of 1:3, or at 4,000 cells per 20 µL of Matrigel®, as single cells every 8 - 14 days. Cultures were analyzed by immunocytochemistry (ICC) to detect secretory markers keratin 7 (KRT7), oviductal glycoprotein 1 (OVGP1), and PAX8, as well as ciliated cell markers acetylated alpha tubulin (TUBA1A) and FOXJ1. Across all donor samples, approximately 16 ± 8% (mean ± SD) of dissociated EpCAM+ FT cells formed 50 - 300 µm diameter cystic organoids within 14 days (n = 8). Cultures can be maintained for at least 5 passages with 14 - 20 cumulative population doublings, at 3 - 4 doublings per passage. ICC analysis confirmed that organoids contain both polarized KRT7+ OVGP1+ PAX8+ secretory cells and acetylated TUBA1A+ FOXJ1+ ciliated cells, indicating multilineage capacity (n = 5). We also tested the compatibility of GyneCult FTOM for growing HGSOC samples, and we observed that 1 of the 3 tumor samples tested generated organoids with a solid and irregular shaped morphology. These cells could undergo a minimum of 5 cumulative population doublings over 5 passages, at 0.5 - 2 doublings per passage; this performance is in line with recently published HGSOC organoid culture methods. These results demonstrate that GyneCult Fallopian Tube Organoid Medium is a robust medium for initiating and culturing FT epithelium as organoids and is a valuable tool for studying FT biology, with the capacity to support HGSOC organoid culture. Citation Format: Victor Ho, Maggie Chan, Manreet Chehal, Alice Liang, Allen Eaves, Sharon Louis, John Stingl. Robust establishment and expansion of human fallopian tube organoids in serum-free culture [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 152.

Abstract 175: Determining the genetic alterations in initiation and progression of high-grade serous ovarian carcinoma

Abstract High grade serous carcinoma (HGSC) is the most common and deadly form of ovarian cancer. Although HGSC can arise from cells in the ovarian surface epithelium (OSE) or fallopian (oviductal) tubal epithelium (TE), the cell state and genetic alterations for HGSC initiation and progression remains unclear. Previous studies with cell type-specific mouse knockouts found inconsistencies in tumorigenesis and chemoresistance. These data can be explained if specific gene signatures in specific cell types have varied tumorigenic potential and chemoresistance. To determine specific gene combinations necessary for OSE and TE malignant transformation, we designed a CRISPR knock out (KO) mini-library against commonly mutated genes of HGSC. Our previous results revealed efficient gene combinations for ex vivo OSE transformation events and a preference for OSE stem cell transformation. To build on our previous studies, we extended our screening methods into TE cells. Our studies utilize an organoid approach to identify the most cancer-prone cell populations. They also test if cell differentiation state determines a specific set of genetic alterations necessary for HGSC initiation. Our screening platform has the potential to determine whether specific genetic alterations in specific cell types are required for malignant transformation. Additionally, our results may improve on previous models of HGSC initiation and progression. Citation Format: Daryl J. Phuong, Amanda P. Armstrong, Andrea Flesken-Nikitin, Alexander Y. Nikitin, John C. Schimenti. Determining the genetic alterations in initiation and progression of high-grade serous ovarian carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 175.

Extracellular matrix in high-grade serous ovarian cancer: Advances in understanding of carcinogenesis and cancer biology.

High-grade serous ovarian cancer (HGSOC) is notoriously known as the "silent killer" of post-menopausal women as it has an insidious progression and is the deadliest gynaecological cancer. Although a dual origin of HGSOC is now widely accepted, there is growing evidence that most cases of HGSOC originate from the fallopian tube epithelium. In this review, we will address the fallopian tube origin and involvement of the extracellular matrix (ECM) in HGSOC development. There is limited research on the role of ECM at the earliest stages of HGSOC carcinogenesis. Here we aim to synthesise current understanding of the contribution of ECM to each stage of HGSOC development and progression, beginning at serous tubal intraepithelial carcinoma (STIC) precursor lesions and proceeding across key events including dissemination of tumourigenic fallopian tube epithelial cells to the ovary, survival of these cells in peritoneal fluid as multicellular aggregates, and colonisation of the ovary. Likewise, as part of the metastatic series of events, serous ovarian cancer cells survive travel in peritoneal fluid, attach to, migrate across the mesothelium and invade into the sub-mesothelial matrix of secondary sites in the peritoneal cavity. Halting cancer at the pre-metastatic stage and finding ways to stop the dissemination of ovarian cancer cells from the primary site is critical for improving patient survival. The development of drug resistance also contributes to poor survival statistics in HGSOC. In this review, we provide an update on the involvement of the ECM in metastasis and drug resistance in HGSOC. Interplay between different cell-types, growth factor gradients as well as evolving ECM composition and organisation, creates microenvironment conditions that promote metastatic progression and drug resistance of ovarian cancer cells. By understanding ECM involvement in the carcinogenesis and chemoresistance of HGSOC, this may prompt ideas for further research for developing new early diagnostic tests and therapeutic strategies for HGSOC with the end goal of improving patient health outcomes.

Increased Local Testosterone Levels Alter Human Fallopian Tube mRNA Profile and Signaling

Fallopian tube epithelium (FTE) plays a critical role in reproduction and can be the site where High Grade Serous Ovarian Carcinoma (HGSOC) originates. Tumorigenic oviductal cells, which are the murine equivalent of human fallopian tube secretory epithelial cells (FTSEC), enhance testosterone secretion by the ovary when co-cultured with the ovary, suggesting that testosterone is part of the signaling axis between the ovary and FTSEC. Furthermore, testosterone promotes proliferation of oviductal cells. Oral contraceptives, tubal ligation, and salpingectomy, which are all protective against developing ovarian cancer, also decrease circulating levels of androgen. In the current study, we investigated the effect of increased testosterone on FTE and found that testosterone upregulates wingless-type MMTV integration family, member 4 (WNT4) and induces migration and invasion of immortalized human fallopian tube cells. We profiled primary human fallopian tissues grown in the microfluidic system SOLO-microfluidic platform -(MFP) by RNA sequencing and found that p53 and its downstream target genes, such as paired box gene 2 (PAX2), cyclin-dependent kinase inhibitor 1A (CDK1A or p21), and cluster of differentiation 82 (CD82 or KAI1) were downregulated in response to testosterone treatment. A microfluidic platform, the PREDICT-Multi Organ System (PREDICT-MOS) was engineered to support insert technology that allowed for the study of cancer cell migration and invasion through Matrigel. Using this system, we found that testosterone enhanced FTE migration and invasion, which was reversed by the androgen receptor (AR) antagonist, bicalutamide. Testosterone also enhanced FTSEC adhesion to the ovarian stroma using murine ovaries. Overall, these results indicate that primary human fallopian tube tissue and immortalized FTSEC respond to testosterone to shift expression of genes that regulate invasion, while leveraging a new strategy to study migration in the presence of dynamic fluid flow.

Oviduct Histopathology of Internal Laying and Egg-Bound Syndrome in Laying Hens

In the egg industry, common reproductive disorders, such as internal laying and egg-bound syndrome, not only reduce egg productivity but also cause deaths in severe cases. In this study, we focused on the oviduct histology of the pathogenesis of internal laying and egg-bound syndrome. We divided the aged laying hens into four groups according to the observation of the abdominal cavity and oviductal lumen: healthy, internal laying, egg-bound, and intercurrent. The percentages of healthy, internal laying, egg-bound, and intercurrent groups were 55%, 17.5%, 15%, and 12.5%, respectively. In all parts of the oviduct (i.e., infundibulum, magnum, isthmus, and uterus), the oviductal epithelium was composed of ciliated epithelial cells and secretory cells. The epithelial region lacking cilia was larger in the entire oviduct of the internal laying, and intercurrent groups than in the healthy group. In the internal laying, egg-bound, and intercurrent groups, significant T-cell infiltration was observed in the lamina propria of the entire oviduct. The morphological alteration of ciliated epithelial cells in the oviducts caused by inflammation may be the underlying cause of the pathogenesis of internal laying and egg-bound syndrome.

Proteomic Profiling of Fallopian Tube-Derived Extracellular Vesicles Using a Microfluidic Tissue-on-Chip System.

The human fallopian tube epithelium (hFTE) is the site of fertilization, early embryo development, and the origin of most high-grade serous ovarian cancers (HGSOCs). Little is known about the content and functions of hFTE-derived small extracellular vesicles (sEVs) due to the limitations of biomaterials and proper culture methods. We have established a microfluidic platform to culture hFTE for EV collection with adequate yield for mass spectrometry-based proteomic profiling, and reported 295 common hFTE sEV proteins for the first time. These proteins are associated with exocytosis, neutrophil degranulation, and wound healing, and some are crucial for fertilization processes. In addition, by correlating sEV protein profiles with hFTE tissue transcripts characterized using GeoMx® Cancer Transcriptome Atlas, spatial transcriptomics analysis revealed cell-type-specific transcripts of hFTE that encode sEVs proteins, among which, FLNA, TUBB, JUP, and FLNC were differentially expressed in secretory cells, the precursor cells for HGSOC. Our study provides insights into the establishment of the baseline proteomic profile of sEVs derived from hFTE tissue, and its correlation with hFTE lineage-specific transcripts, which can be used to evaluate whether the fallopian tube shifts its sEV cargo during ovarian cancer carcinogenesis and the role of sEV proteins in fallopian tube reproductive functions.

Exploiting the Receptor-Binding Domains of R-Spondin 1 to Target Leucine-Rich Repeat-Containin G-Coupled Protein Receptor 5-Expressing Stem Cells in Ovarian Cancer.

Leucine-rich repeat-containing G-protein-coupled receptor (LGR5) and LGR6 mark epithelial stem cells in normal tissues and tumors. They are expressed by stem cells in the ovarian surface and fallopian tube epithelia from which ovarian cancer arises. High-grade serous ovarian cancer is unique in expressing unusually high levels of LGR5 and LGR6 mRNA. R-spondins are the natural ligands for LGR5 and LGR6 to which they bind with nanomolar affinity. To target stem cells in ovarian cancer, we used the sortase reaction to site-specifically conjugate the potent cytotoxin monomethyl auristatin E (MMAE) via a protease sensitive linker to the two furin-like domains of RSPO1 (Fu1-Fu2) that mediate its binding to LGR5 and LGR6 and their co-receptors Zinc And Ring Finger 3 and Ring Finger Protein 43 via a protease-cleavable linker. An immunoglobulin Fc domain added to the N-terminal end served to dimerize the receptor-binding domains so that each molecule carries two MMAE. The resulting molecule, FcF2-MMAE, demonstrated: 1) selective LGR5-dependent low nanomolar cytotoxicity against ovarian cancer cells in vitro; 2) selectivity that was dependent on binding to both the LGR receptors and ubiquitin ligase co-receptors; 3) favorable stability and plasma pharmacokinetic properties when administered intravenously with an elimination half-life of 29.7 hours; 4) selective inhibition of LGR5-rich as opposed to isogenic LGR5-poor tumors in vivo; and, 5) therapeutic efficacy in three aggressive wild-type human ovarian cancer xenograft models. These results demonstrate the successful use of the Fu1-Fu2 domain of RSPO1 as a drug carrier and the ability of FcF2-MMAE to target cells in tumors that express stem cell markers. SIGNIFICANCE STATEMENT: FcF2-MMAE is a novel cancer therapeutic that exploits the high-affinity binding domains of RSPO1 to target monomethyl auristatin E to tumor stem cells that express LGR5. FcF2-MMAE has low nanomolar LGR5-dependent cytotoxicity in vitro, favorable pharmacokinetics, and differential efficacy in an isogenic LGR5-poor versus LGR5-rich ovarian cancer xenograft model when given on a weekly schedule.

Escaping Behavior of Sperms on the Biomimetic Oviductal Surface

Before fertilization, sperms adhere to oviductal epithelium cells, and only a restrictive number of winner sperms can escape to reach the egg. To study the sperm escape behavior from the oviductal surface, we developed a microfluidic chip to fabricate an adhesive surface and to create a gradient of progesterone (P4) for mimicking the oviduct microenvironment in vivo. We identified three sperm motion patterns in such a microenvironment─anchored spin, run-and-spin, and escaped mode. By using kinetic analysis, we verified the hypothesis that the responsive rotation energy anchored with the adhered sperm head determines whether the sperm is trapped or detaching, which is defined as the hammer flying strategy of successful escape after accumulating energy in the process of rotating. Intriguingly, this hammer-throw escaping is able to be triggered by the P4 biochemical stimulation. Our results revealed the tangled process of sperm escape before fertilization in the ingenious microfluidic system.

An epileptogenic intracranial cystic lesion lined with fallopian tube-type epithelium: illustrative case.

Intracranial cystic lesions are often a trigger for epileptic seizures. However, there has never been a report of a cystic lesion lined with fallopian tube-type epithelium. A 48-year-old female presented with a cystic lesion in the right occipital lobe, which gradually grew over 8 years. Right occipital lobe epilepsy was diagnosed based on visual aura, convulsive seizures, and electroencephalogram findings and the cyst was surgically removed. Further examination revealed the cyst was lined with ciliated cells, which had morphological and immunohistochemical features similar to those of fallopian tube epithelium. The characteristics of the cyst did not conform to any known types of benign cystic lesion. To the authors' knowledge, no such cyst has been reported before. The authors discuss the origins and pathogenesis of this unfamiliar cystic lesion.

Abstract B030: PAX8 modulates the tumor microenvironment of high grade serous ovarian cancer through changes in the secretome

Abstract High grade serous ovarian cancer (HGSC), the most common and lethal form of ovarian cancer, is a highly heterogeneous disease. HGSC is rarely detected early, and likely 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 ovarian serous tumors 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. Our data shows that PAX8 loss by CRISPR and shRNA in HGSC cell lines causes tumor cell death and reduces cell migration and invasion. Additionally, loss of PAX8 significantly reduced tumor burden in a xenograft model of HGSC. Herein, secretome analysis was performed on PAX8 deleted cells, and we identified a reduction of the extracellular matrix (ECM) components, collagen and fibronectin. Immunoblotting and immunofluorescence in PAX8 deleted OVCAR8 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 remodeling of the tumor microenvironment. Furthermore, PAX8 loss reduced the integrity of 3D spheroids and caused a reduction of ECM proteins in 3D cultures: fibronectin and collagen. Due to the ubiquitous expression of PAX8 in HGSC, regardless of cell origin, and evidence that reducing PAX8 protein levels inhibits tumor growth, a PAX8 inhibitor could be a promising drug lead against HGSC. To accomplish this, we generated a murine oviductal epithelial (MOE) cell line stably expressing the PAX8 promoter driving luciferase reporter protein. 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-luciferase. We identified two hits: losartan and captropril, both inhibitors of the renin-angiotensin pathway that inhibit PAX8 expression and function. We are currently working to monitor if these compounds reduce tumor burden via PAX8 reduction. Further, if PAX8 reduction in vivo diminishes collagen and fibronectin, this may impact immune cell infiltration via changes in the tumor microenvironment. Overall, this study validates PAX8 as a regulator of ECM deposition in the tumor microenvironment. Citation Format: Amrita Salvi, Laura R. Hardy, Kimberly N. Heath, Samantha Watry, Melissa R. Pergande, Stephanie M. Cologna, Joanna E. Burdette. PAX8 modulates the tumor microenvironment of high grade serous ovarian cancer through changes in the secretome [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B030.

Abstract PR005: TP53 somatic evolution in healthy fallopian tube across the full spectrum of human lifespan

Abstract Introduction: TP53 is the most mutated gene in human cancers but research in recent years has demonstrated that TP53 mutations are also prevalent in healthy tissue. Little is known, however, about how these mutations accumulate with age and how this process might differ between and within individuals. This gap in knowledge is largely due to the difficulty of measuring clonal expansions in normal tissue since mutant clones are typically small and escape the detection of standard sequencing technologies. We previously demonstrated the high sensitivity of duplex sequencing (duplex-seq) to detect low frequency mutations in normal tissue. Here we use duplex-seq to characterize TP53 mutations across the full range of human lifespan in fallopian tube epithelium. Fallopian tube is the site of origin of high-grade serous ovarian carcinoma, a very aggressive cancer type that is almost exclusively driven by TP53 mutations. We hypothesize that TP53 clonal expansions increase in number, size, and pathogenicity during human lifespan, especially in the fimbria, which is the distal part of the tube and the predominant site for cancer formation. Methods: Frozen fallopian tube was collected at autopsy from 84 individuals spanning the full range of human lifespan (from newborn to &amp;gt;90-year-old). For most individuals, collection included a sample from the fallopian tube fimbria (distal part) and ampulla (proximal part). For a subset of patients, both right and left fallopian tubes were sampled. Frozen OCT embedded tissue was sectioned, pathologically examined to determine the presence of fallopian tube epithelium, and macrodissected. TP53 mutations were identified by ultra-deep duplex-seq (12,000x) and were compared between fallopian tube fimbria and ampulla, between right and left tubes, across decades of age, and with cancer mutations reported in the COSMIC database. Results: About 11% of samples have been analyzed, and the full cohort is expected to be completed within the next two months. TP53 mutations were identified in all individuals at an average of 6 mutations per sample (min=0, max=15). The number of mutations significantly increased with age and, in this smaller subset, did not significantly differ between bilateral samples or between fimbria and ampulla. The size of the mutant clones also increased with age. Most mutations were missense, but nonsense, indels, and splice mutations were also detected, especially at older ages. More than half of the mutations were predicted to be pathogenic and coincided with mutations commonly found in ovarian cancer. Conclusions: Ultra-deep sequence has enabled unprecedented resolution to characterize TP53 somatic evolution in normal tissue. TP53 mutant clones accumulate in the fallopian tube with age and are enriched for pathogenic mutations, indicating clonal expansion upon selective advantage. Deep characterization of these mutant clones will inform our knowledge of the normal physiological process of somatic evolution during healthy aging and its potential contribution to cancer formation later in life. Citation Format: Rosana Risques, Coohleen Coombes, Jeanne Fredrickson, Elizabeth U. Parker, Brendan Kohrn, Elena S. Latorre-Esteves, Emma Hazard, Eden M. Milan, Ronit Katz. TP53 somatic evolution in healthy fallopian tube across the full spectrum of human lifespan [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr PR005.

Glutathione peroxidase 1 and 2 during preimplantation period of pregnancy in mouse.

This study describes the presence of glutathione peroxidase (GPx) 1 and 2 in oocytes, preimplantation embryos, and mouse female genital organs. GPx1 and 2 are antioxidant enzymes, which play important roles in protection of cells against oxidation, which may be formed during cell physiological processes. After superovulation of female mice, oocytes and preimplantation embryos (O/PE) were isolated for immunofluorescent analysis, female genital organs were removed for immunohistochemical and Western blot analyses. Using immunofluorescence, GPx1 was detected in all OP/E, where it formed clusters near nuclei, or under the cytoplasmic membrane. GPx2 was not detected in any O/PE. Using immunohistochemistry, GPx1 was observed in corpus luteum and oocytes, and in oviductal and uterine epithelium. GPx2 was detected in corpus luteum, but not in oocytes. Oviductal and uterine epithelium was mostly negative. Using Western blot, two GPx1 bands of different molecular weights were detected in uterus. One GPx2 band was observed in all investigated organs. These results show that both enzymes may be important during preimplantation period of pregnancy in genital organs, GPx1 also in O/PE. GPx2 may play roles in embryo after the implantation, when gastrointestinal tract is formed (Fig. 10, Ref. 75).