Placental Alkaline Phosphatase Research Articles

A case of a pineal parenchymal tumor of intermediate differentiation with bifocal lesions differentiated by negative placental alkaline phosphatase in the spinal fluid.

Placental alkaline phosphatase (PLAP) in the spinal fluid is helpful for the diagnosis of intracranial germinomas. Bifocal lesions involving the pineal and pituitary regions have also been reported as characteristic findings of intracranial germinomas. We present a rare case of a 15-year-old boy with a pineal parenchymal tumor of intermediate differentiation (PPTID) with bifocal lesions negative for PLAP. Magnetic resonance imaging of the brain revealed bifocal mass lesions in the pineal and suprasellar regions and non-communicating hydrocephalus. We initially suspected a germinoma based on imaging findings, but all tumor markers, including PLAP, in the spinal fluid were negative. Based on these results, germinoma was considered less likely, and an endoscopic third ventriculostomy and endoscopic tumor biopsy were performed for diagnosis. The histopathological diagnosis was PPTID, corresponding to World Health Organization grade 3, in both pineal and suprasellar specimens. A craniotomy for tumor removal was performed, resulting in total resection. PLAP is known to have high sensitivity and extremely high negative predictive value for germinomas. Although bifocal lesions highly suggest germ cell tumors, there are exceptions, as in the present case. This case suggests that PLAP measurements are useful for differentiation, leading to appropriate treatment strategies.

Customizing EV-CATCHER to Purify Placental Extracellular Vesicles from Maternal Plasma to Detect Placental Pathologies.

Placenta Accreta Spectrum (PAS) is a life-threatening condition in which placental trophoblastic cells abnormally invade the uterus, often up to the uterine serosa and, in extreme cases, tissues beyond the uterine wall. Currently, there is no clinical assay for the non-invasive detection of PAS, and only ultrasound and MRI can be used for its diagnosis. Considering the subjectivity of visual assessment, the detection of PAS necessitates a high degree of expertise and, in some instances, can lead to its misdiagnosis. In clinical practice, up to 50% of pregnancies with PAS remain undiagnosed until delivery, and it is associated with increased risk of morbidity/mortality. Although many studies have evaluated the potential of fetal biomarkers circulating in maternal blood, very few studies have evaluated the potential of circulating placental extracellular vesicles (EVs) and their miRNA contents for molecular detection of PAS. Thus, to purify placental EVs from maternal blood, we customized our robust ultra-sensitive immuno-purification assay, termed EV-CATCHER, with a monoclonal antibody targeting the membrane Placental Alkaline Phosphatase (PLAP) protein, which is unique to the placenta and present on the surface of placental EVs. Then, as a pilot evaluation, we compared the miRNA expression profiles of placental EVs purified from the maternal plasma of women diagnosed with placenta previa (controls, n = 16); placenta lying low in uterus but not invasive) to those of placental EVs purified from the plasma of women with placenta percreta (cases, n = 16), PAS with the highest level of invasiveness. Our analyses reveal that miRNA profiling of PLAP+ EVs purified from maternal plasma identified 40 differentially expressed miRNAs when comparing these two placental pathologies. Preliminary miRNA pathway enrichment and gene ontology analysis of the top 14 upregulated and top nine downregulated miRNAs in PLAP+ EVs, purified from the plasma of women diagnosed with placenta percreta versus those diagnosed with placenta previa, suggests a potential role in control of cellular invasion and motility that will require further investigation.

HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL FEATURES OF DIFFERENTIATED TROPHOBLAST IN CHORIONIC VILLI OF THE PLACENTA IN PRETERM LABOR

The importance of studying the histochemical and immunohistochemical features of the diff erentiated trophoblast in chorionic villi of the placenta in preterm labor is determined by the threatening nature of this condition for both mother and fetus, as well as its high prevalence and serious consequences for the health of both. The understanding of the damage to the trophoblast of chorionic villi in the placenta can be expanded by histochemical and immunohistochemical methods, which allow the assessment of the concentration of specifi c marker molecules in one way or another.Objective. To determine certain histochemical and immunohistochemical characteristics of proteins in the trophoblast of theintermediate and terminal chorionic villi of the placenta in preterm labor.Material and Methods. The obtained material (30 placentas from preterm deliveries and 30 placentas from normalpregnancies) was fi xed for 20-24 hours in 10 % neutral formalin solution buff ered in Lilly’s phosphate buff er. After tissue removal, the placental tissue was dehydrated in an ascending ethanol series and embedded in paraffi n at a temperature of approximately 58 °C. Serial histologic sections were cut at 5.0 μm thickness using an MS-2 sliding microtome. After deparaffi nization, histological sections were stained with hematoxylin and eosin, histochemical methods for total protein with bromophenol blue according to Bonhéme, and immunohistochemical techniques according to the manufacturer’s protocols (Dako, Denmark). In particular, immunohistochemical reactions were performed with monoclonal antibodies against trophoblast hormone- placental lactogen and placental alkaline phosphatase. Visualization of primary antibodies was performed using the Dako polymer visualization system with diaminobenzidine as chromogen (resulting in brown staining of the sites of studied antigens). In addition to the descriptive method of histopathologic research, computer morphometry of digital microphotographs of histologic sections was performed using a Delta Optical Evolution 100 microscope and an Olympus SP550UZ digital camera. Digital copies of the images were processed using a legitimate copy of the ImageJ v1.52f computer program developed for histometric studies (National Institutes of Health, USA). Specifi cally, the evaluation of staining intensity (optical density) was performed on digital microphotographs using the method of computer microdensitometry. For this purpose, a microprobe method was used to obtain a computer brightness value in an 8-bit analysis system with 256 gray levels – from black (0) to white (255).The obtained values were then transformed into relative optical density values (r.OD) by logarithmic transformation (naturallogarithm method). The relative optical density value ranges from 0 (absolute transparency of the object) to 1 (absolute opacity of the object). The obtained digital data were processed using statistical analysis methods. A legitimate copy of the statistical analysis computer program PAST v4.14 was used, with a preliminary check for normal distribution using the Shapiro- Wilk test. Since, according to this test, the hypothesis of normal distribution was not rejected for the statistical samples studied (at p=0.05), parametric methods of statistical analysis were applied: calculation of the mean and its standard error, Student’s t-test (two-tailed, unpaired). In addition, the non-parametric Mann- Whitney test was used for the reliability of the conclusions. The research was conducted as part of the scientifi c research project «Preservation and Restoration of Reproductive Health in Women and Girls with Obstetric and Gynecological Pathology» at the Department of Obstetrics and Gynecology of Bukovinian State Medical University (state registration number 0121U110020, duration 2021-2025).Results. Microscopic examination of histological sections stained with hematoxylin and eosin did not reveal any diff erencesin the structure of chorionic villus trophoblast in the placenta of preterm labor compared to normal pregnancy. However,histochemical and immunohistochemical methods of investigation revealed a number of features in the trophoblast of chorionic villi, where fundamental events related to substance exchange occur – intermediate immature, intermediate mature, terminal villi, including terminal «specialized villi».Conclusions. According to the obtained histochemical and immunohistochemical data, in preterm labor, compared to normalpregnancy, no changes are observed in the trophoblast of intermediate immature villi, while in intermediate mature and terminal villi, there is a decrease in histochemical staining for total protein and immunohistochemical staining for specifi c trophoblast proteins – placental lactogen hormone and placental alkaline phosphatase enzyme.

Abstract LB045: Exploiting biparatopic binding to deliver novel, differentiated ALPP/ALPPL2 targeting protein drug conjugates

Abstract The placental alkaline phosphatases ALPP and ALPPL2 are attractive targets for antibody and protein-drug conjugate (ADC and PDC) approaches. These GPI-anchored cell-surface proteins, which share very high sequence identity, are over-expressed in a number of different solid tumor indications including testicular, ovarian, endometrial, gastric, pancreatic and non-small cell lung cancers but have very little expression on normal adult tissues. Consequently, there is significant interest in exploiting ALPP/ALPPL2 for the development of new targeted oncology therapeutics, and an ALPP/ALPPL2 ADC, utilizing a classical full-length IgG antibody, is currently in Phase I clinical trials. The exploitation of biparatopic binding is an attractive approach for improving the therapeutic index of ADCs. This mode of target engagement increases the effective number of binding sites on the tumor cells and can promote internalisation and trafficking, thereby delivering increased efficacy for the same payload bolus and opening up patient populations with lower target expression. This can lead to a widening of the therapeutic window, by improving the efficacy achievable for a given amount of payload administered (often defined as the “platform” toxicity). For the development of biparatopic conjugates, the use of small protein domain binders offers advantages over the use of full-length antibodies, as they can readily be reformatted into a variety of biparatopic architectures to deliver homogeneous drug conjugates in high yield. Additionally, smaller protein formats have the capacity to penetrate deeper into solid tumors than large antibodies. We have identified a series of highly selective, high affinity ALPP/ALPPL2 single domain VHH binders, which target distinct epitopes on the protein and which, importantly, show no binding to the closely related ALPI or ALPL isoforms (which have high normal tissue expression). Using protein engineering approaches, a series of homogenous site-specifically labelled biparatopic PDCs have been developed employing the clinically validated vcMMAE (vedotin) payload. In pre-clinical studies, these PDC agents demonstrate excellent anti-tumor efficacy in vivo in ALPP/ALPPL2 positive cell-line derived xenograft models of gastric, pancreatic and ovarian cancer displaying a range of target expression. In benchmarking studies, lead biparatopic PDCs show increased internalisation and target-mediated in vitro cell kill potency compared to an ALPP/ALPPL2 targeting ADC. Additionally, in multiple CDX models, lead biparatopic PDCs demonstrate improved efficacy over an ALPP/ALPPL2 ADC both on a mg/kg and on a payload equivalents basis, in both single dose and multi-dose studies, providing complete regressions. Based on this excellent efficacy profile and favourable developability characteristics, preclinical development activities have been initiated. Citation Format: Graham Cotton, Estelle G. McLean, Paul Trumper, Mark Wappett, Stephanie Gatdula, Stacey Bell, Greg Papadakos, Kieron Lucas, Stephanie Burton, Chiara Saladino, Georgiana Parau, Aidan McCann, Jennifer Thom, Aaron N. Cranston, Tim Harrison. Exploiting biparatopic binding to deliver novel, differentiated ALPP/ALPPL2 targeting protein drug conjugates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB045.

A method to isolate syncytiotrophoblast-derived medium-large extracellular vesicle small RNA from maternal plasma

Syncytiotrophoblast-derived extracellular vesicles (STB-EVs) have an important role in placental research: both as mediators of feto-maternal signalling and as liquid biopsies reflecting placental health. Recent evidence highlights the importance of STB-EV RNA. Isolation of STB-EV RNA from maternal blood is therefore an important challenge. We describe a novel technique where we first separate medium-large particles from plasma using centrifugation then use a highly specific bead-bound antibody to placental alkaline phosphatase to separate STB-EVs from other similar-sized particles. We demonstrate the yield and size profile of small RNA obtained from plasma STB-EVs. We present data confirming isolation of placenta-derived micro RNA from maternal plasma using this method. The technique has been successfully applied to validate novel RNA discoveries from placental perfusion models. We propose it could offer new insights through transcriptomic analyses, providing a syncytiotrophoblast-specific signal from maternal blood.

Shedding of Syncytiotrophoblast-Derived Extracellular Vesicles Is Increased in Placenta Previa and Accreta Spectrum.

Placenta accreta spectrum (PAS) refers to excessive placental invasion into the maternal uterus and it is associated with high risk of obstetric haemorrhage and adverse maternal-neonatal outcomes. Currently, no specific circulating biomarkers of PAS have been identified. Given that in PAS disorders, the depth and the extension of placental invasion into the uterus are expected to be increased, in this study, we analysed plasma levels of syncytiotrophoblast-derived extracellular vesicles (STBEVs) in women with placenta previa (PP), at a high risk of PAS disorders, and pregnant women with normal placentation. Venous blood samples were collected from 35 women with ultrasonographic diagnosis of PP and 35 women with normal placentation, matched for gestational age. Plasma samples were ultracentrifuged at 120.000g to collect extracellular vesicles (EVs). To identify and quantify plasma placenta-derived EVs (or STBEVs), EVs were analysed by flow cytometry using a monoclonal antibody against placental alkaline phosphatase (PLAP). Plasma levels of STBEVs were significantly higher in PP patients compared to controls. Plasma levels of STBEVs in women with PP and PAS showed a trend to a higher concentration compared to women with PP without PAS, although not reaching a statistical significance. Circulating STBEVs are potential candidates as biological markers to be integrated to ultrasonography in the antenatal screening programme for PAS. More studies are needed to confirm our observation in a larger cohort of patients and to analyse a possible association between high circulating levels of STBEVs and PAS.

Development of a heat-stable alkaline phosphatase reporter system for cis-regulatory analysis and its application to 3D digital imaging of Xenopus embryonic tissues.

Xenopus is one of the essential model systems for studying vertebrate development. However, one drawback of this system is that, because of the opacity of Xenopus embryos, 3D imaging analysis is limited to surface structures, explant cultures, and post-embryonic tadpoles. To develop a technique for 3D tissue/organ imaging in whole Xenopus embryos, we identified optimal conditions for using placental alkaline phosphatase (PLAP) as a transgenic reporter and applied it to the correlative light microscopy and block-face imaging (CoMBI) method for visualization of PLAP-expressing tissues/organs. In embryos whose endogenous alkaline phosphatase activities were heat-inactivated, PLAP staining visualized various tissue-specific enhancer/promoter activities in a manner consistent with green fluorescent protein (GFP) fluorescence. Furthermore, PLAP staining appeared to be more sensitive than GFP fluorescence as a reporter, and the resulting expression patterns were not mosaic, in striking contrast to the mosaic staining pattern of β-galactosidase expressed from the lacZ gene that was introduced by the same transgenesis method. Owing to efficient penetration of alkaline phosphatase substrates, PLAP activity was detected in deep tissues, such as the developing brain, spinal cord, heart, and somites, by whole-mount staining. The stained embryos were analyzed by the CoMBI method, resulting in the digital reconstruction of 3D images of the PLAP-expressing tissues. These results demonstrate the efficacy of the PLAP reporter system for detecting enhancer/promoter activities driving deep tissue expression and its combination with the CoMBI method as a powerful approach for 3D digital imaging analysis of specific tissue/organ structures in Xenopus embryos.

Isolation of serum-derived placental/amnio-chorionic extracellular vesicles across pregnancy by immunoaffinity using PLAP and HLA-G.

Circulating extracellular vesicles of placental/amniochorionic origin carry placental/amniochorionic proteins and nucleic acids with the potential to facilitate non-invasive diagnosis of pregnancy-related disorders. The study reports an improvised method for the enriched isolation of extracellular vesicles of placental/amniochorionic origin using the two markers, PLAP and HLA-G. Extracellular vesicles (EVs) are membrane-bound nanovesicles secreted from the cells into extracellular space and body fluids. They are considered 'fingerprints of parent cells', which can reflect their physiological and functional states. During pregnancy, EVs are produced by the syncytiotrophoblasts and extravillous trophoblasts and are released into the maternal bloodstream. In the present study, placental alkaline phosphatase (PLAP)-specific extracellular vesicles were isolated from maternal serum-derived EVs (SDE) across pregnancy. Transmission electron microscopy and dynamic light scattering analysis showed that the isolated EVs exhibited a spherical morphology with ~30-150 nm size range. Nanoparticle tracking analysis indicated that the concentration of PLAP+ serum-derived EVs (PLAP+-SDE) increased across the gestation. PLAP+-SDE contained DNA with LINE1 promoter methylation pattern. C19 miRNA cluster miRNAs (miR 515-5p, 519e and 520f) were present in PLAP+-SDE along with other miRNAs (miR-133-3p, miR210-3p and miR-223-3p). PLAP+-SDE confirmed the presence of EV markers (CD63 and CD9), along with placental proteins (PLAP and cullin 7). A modified novel strategy to extract an enriched population of circulating placental/amniochorionic EVs was devised employing an additional marker of extravillous trophoblasts, human leukocyte antigen G (HLA-G), along with PLAP. The isolated pooled placental/amniochorionic (PLAP+&HLA-G+) serum-derived EVs (PP-SDE) showed ~two-fold increased protein levels of HLA-G in the third-trimester pregnant women compared to the non-pregnant controls. Future studies will be focused on validation of this novel strategy to isolate an enriched population of placental/amniochorionic EVs to facilitate a better understanding of placental physiology and pathophysiology.

Differential 5'-tRNA Fragment Expression in Circulating Preeclampsia Syncytiotrophoblast Vesicles Drives Macrophage Inflammation.

The relationship between placental pathology and the maternal syndrome of preeclampsia is incompletely characterized. Mismatch between placental nutrient supply and fetal demands induces stress in the syncytiotrophoblast, the layer of placenta in direct contact with maternal blood. Such stress alters the content and increases the release of syncytiotrophoblast extracellular vesicles (STB-EVs) into the maternal circulation. We have previously shown 5'-tRNA fragments (5'-tRFs) constitute the majority of small RNA in STB-EVs in healthy pregnancy. 5'-tRFs are produced in response to stress. We hypothesized STB-EV 5'-tRF release might change in preeclampsia. We perfused placentas from 8 women with early-onset preeclampsia and 6 controls, comparing small RNA expression in STB-EVs. We used membrane-affinity columns to isolate maternal plasma vesicles and investigate placental 5'-tRFs in vivo. We quantified 5'-tRFs from circulating STB-EVs using a placental alkaline phosphatase immunoassay. 5'-tRFs and scrambled RNA controls were added to monocyte, macrophage and endothelial cells in culture to investigate transcriptional responses. 5'-tRFs constitute the majority of small RNA in STB-EVs from both preeclampsia and normal pregnancies. More than 900 small RNA fragments are differentially expressed in preeclampsia STB-EVs. Preeclampsia-dysregulated 5'-tRFs are detectable in maternal plasma, where we identified a placentally derived load. 5'-tRF-Glu-CTC, the most abundant preeclampsia-upregulated 5'-tRF in perfusion STB-EVs, is also increased in preeclampsia STB-EVs from maternal plasma. 5'-tRF-Glu-CTC induced inflammation in macrophages but not monocytes. The conditioned media from 5'-tRF-Glu-CTC-activated macrophages reduced eNOS (endothelial NO synthase) expression in endothelial cells. Increased release of syncytiotrophoblast-derived vesicle-bound 5'-tRF-Glu-CTC contributes to preeclampsia pathophysiology.

Association between Plasma HLA-DR+ Placental Vesicles and Preeclampsia: A Pilot Longitudinal Cohort Study.

(1) Background: Preeclampsia (PE) usually presents with hypertension and proteinuria, related to poor placentation. Reduced maternal-fetal immunological tolerance is a possible trigger of inadequate placentation. Aberrant antigen expression of HLA-DR has been observed in the syncytiotrophoblast of PE patients. In this study, we analyzed plasma levels of Human Leukocyte Antigen (HLA)-DR+ syncytiotrophoblast-derived extracellular vesicles (STEVs) during the three trimesters of pregnancy in relation to PE onset. (2) Methods: Pregnant women underwent venous blood sampling during the three trimesters. STEVs were collected from plasma via ultracentrifugation (120,000 g) and characterized by Western blot, nanotracking analysis and flow cytometry for the expression of Placental Alkaline Phosphatase (PLAP), a placental-derived marker, and HLA-DR. (3) Results: Out of 107 women recruited, 10 developed PE. STEVs were detected in all three trimesters of pregnancy with a zenith in the second trimester. A significant difference was found between the non-PE and PE groups in terms of plasma levels of HLA-DR+ STEVs during all three trimesters of pregnancy. (4) Conclusions: More research is needed to investigate HLA-DR+ as a potential early marker of PE.

Rudimentary and Incipient-Yolk Sac Tumour- Testis

Yolk sac tumour of testis configures as a germ cell neoplasm comprised of cellular articulations or structures simulating embryonic or foetal yolk sac, allantois and extra-embryonal mesenchyme. Testicular yolk sac tumour is pre-eminently comprised of prepubertal subtype which is non-concordant to germ cell neoplasia in situ, emerges as a ‘pure’ neoplasm and demonstrates multiple gains within chromosome 1q, 20q or 22 and losses within chromosomes 1p, 4 or 6q. Postpubertal subtype is concurrent to germ cell neoplasia in situ (GCNIS), preponderantly configures as a component of ‘mixed tumour’ and occurs due to testicular dysgenesis syndrome, subfertility or as single nucleotide polymorphism (SNP) variants within KITLG, SPRY4 or DMRT1 genes and expounds gain of isochromosome 12p. Upon microscopy, neoplasm may configure distinctive configurations as microcystic or reticular pattern, macrocystic pattern, myxomatous pattern, sarcomatoid or spindle shaped cellular pattern, solid pattern, glandular or alveolar pattern, endodermal sinus or perivascular pattern, hepatoid pattern, papillary pattern, parietal pattern or poly-vesicular vitelline pattern. Yolk sac tumour appears immune reactive to alpha fetoprotein (AFP), glypican 3, SALL4, pancytokeratin, villin or CK7. Neoplastic cells appear immune non-reactive to OCT3/4, CD30, CD117, placental alkaline phosphatase (PLAP), podoplanin (D2-40), inhibin, GATA3 or p63. Testicular yolk sac tumour requires segregation from neoplasms as teratoma, seminoma, embryonal carcinoma, rete testis with hyaline globules and microcystic leydig cell tumour. Tumefaction preponderantly depicts elevated levels of serum alpha fetoprotein (AFP). Testicular yolk sac tumour may be optimally subjected to surgical manoeuvers as orchiectomy.

Anti-enzymatic and DNA docking studies of montelukast: A multifaceted molecular scaffold with in vitro investigations, molecular expression analysis and molecular dynamics simulations

Montelukast, an approved leukotriene receptor 1 (Cys-LT 1) antagonist with anti-inflammatory properties is used for the treatment of asthma and allergic rhinitis. In the present studies, montelukast was subjected to in vitro inhibitory assays followed by kinetic and in silico investigations. Montelukast demonstrated inhibitory activity against yeast α-glucosidase (IC50 44.31 ± 1.21 μM), jack bean urease (JB urease, IC50 8.72 ± 0.23 μM), human placental alkaline phosphatase (hPAP, IC50 17.53 ± 0.19 μM), bovine intestinal alkaline phosphatase (bIAP, IC50 15.18 ± 0.23 μM) and soybean 15-lipoxygenase (15-LOX, IC50 2.41 ± 0.13 μM). Kinetic studies against α-glucosidase and urease enzymes revealed its competitive mode of inhibition. Molecular expression analysis of montelukast in breast cancer cell line MCF-7 down-regulated AP by a factor of 0.27 (5 μM) compared with the 0.26 value for standard inhibitor levamisole (10 μM). Molecular docking estimated a binding affinity ranging −8.82 to −15.65 kcal/mol for the enzymes. Docking against the DNA dodecamer (ID: 1BNA) observed −9.13 kcal/mol via minor groove binding. MD simulations suggested stable binding between montelukast and the target proteins predicting strong inhibitory potential of the ligand. Montelukast features a chloroquinoline, phenyl ring, a cyclopropane group, a carboxylic group and a sulfur atom all of which collectively enhance its inhibitory potential against the said enzymes. These in vitro and computational investigations demonstrate that it is possible and suggested that the interactions of montelukast with more than one targets presented herein may be linked with the side effects presented by this drug and necessitate additional work. The results altogether suggest montelukast as an important structural scaffold possessing multitargeted features and warrant further investigations in repurposing beyond its traditional pharmacological use.

A Targeted Approach for Evaluating DUX4-Regulated Proteins as Potential Serum Biomarkers for Facioscapulohumeral Muscular Dystrophy Using Immunoassay Proteomics.

Facioscapulohumeral muscular dystrophy (FSHD) is a progressive myopathy caused by misexpression of the double homeobox 4 (DUX4) embryonic transcription factor in skeletal muscle. Identifying quantitative and minimally invasive FSHD biomarkers to report on DUX4 activity will significantly accelerate therapeutic development. The goal of this study was to analyze secreted proteins known to be induced by DUX4 using the commercially available Olink Proteomics platform in order to identify potential blood-based molecular FSHD biomarkers. We used high-throughput, multiplex immunoassays from Olink Proteomics to measure the levels of several known DUX4-induced genes in a cellular myoblast model of FSHD, in FSHD patient-derived myotube cell cultures, and in serum from individuals with FSHD. Levels of other proteins on the Olink Proteomics panels containing these DUX4 targets were also examined in secondary exploratory analysis. Placental alkaline phosphatase (ALPP) levels correlated with DUX4 expression in both cell-based FSHD systems but did not distinguish FSHD patient serum from unaffected controls. ALPP, as measured with the Olink Proteomics platform, is not a promising FSHD serum biomarker candidate but could be utilized to evaluate DUX4 activity in discovery research efforts.

Intra-Abdominal Testicular Seminoma In A Phenotypic Female: A Case of XY, Disorder of Sex Development Complicated with Seminoma

Disorder of sex development (DSD) complicated with seminoma is infrequently encountered in clinical practice. In order to diagnose the condition histopathological, immunohistochemical, and karyotype analysis can play the pivotal role. Additionally, prognosis of such patients largely depends upon the pathological staging at the time of initial diagnosis. Hence, the aim of this study was to determine the significance of macroscopic and microscopic examination together with immunohistochemical analysis in diagnosis and prognosis of XY, Disorder of sex development (DSD) which is often known to be complicated by intra-abdominal seminoma. A twenty eight year old patient was admitted into Bangabandhu Sheikh Mujib Medical University (BSMMU) presenting with a right sided adnexal mass for one year. Magnetic Resonance Imaging (MRI) showed a large lobulated soft tissue mass in right adnexal region accompanied by infantile uterus. Interestingly, chromosomal analysis of this patient was found to be 46 XY. Post-resection histological studies revealed an intra-abdominal seminoma at a stage of pT2NxMx. The tumour cells expressed immunoreactivity to both Placental Alkaline Phosphatase (PLAP) and C-kit. Sir Salimullah Med Coll J 2023; 31: 60-64

Evaluating the Role of Placental Alkaline Phosphatase in Preterm Labor: Correlations with Gestational Age, Placental Maturity, and Newborn Nutrition

Preterm labor, one of the common pathological phenomena during pregnancy, necessitates prompt and accurate detection to safeguard the health of both pregnant women and newborns. This study focused on placental alkaline phosphatase, a pregnancy-specific enzyme, and its potential role in identifying preterm labor. This study aimed to investigate the relationship between placental alkaline phosphatase, placental maturity, the nutritional status of newborns, and its utility in evaluating preterm labor. A total of 85 pregnant women with singleton pregnancy of more than 15 weeks of gestation admitted to our hospital from March 2022 to May 2023 were selected as study subjects. Our study revealed a positive correlation between PLAP levels and both gestational age and placental maturity (P < 0.05). Our findings indicated that with an increase in gestational age and placental maturity, there was a corresponding increase in placental alkaline phosphatase levels. However, there were no differences in placental alkaline phosphatase between pregnant women of Grade III and Grade II in terms of placental maturity (P > 0.05). There was a significant increase in placental alkaline phosphatase levels among pregnant women who gave birth prematurely (P < 0.05). The receiver operating characteristic curve showed that placental alkaline phosphatase had an excellent effect on the evaluation of preterm labor (P < 0.05). However, there were no significant differences in placental alkaline phosphatase between the pregnant women with and without postpartum complications (P > 0.05). Lastly, placental alkaline phosphatase was found to have an inverse relationship with levels of neonatal albumin and transferrin levels (P < 0.05).

МОРФОЛОГИЯ СИНЦИТИОТРОФОБЛАСТА ПЛАЦЕНТЫ В ТЕЧЕНИЕ ВСЕГО СРОКА НЕОСЛОЖНЕННОЙ БЕРЕМЕННОСТИ

The placenta is a fetal organ providing the interchange between mother and fetus. An important role in the regulation of local hemostasis belongs to the so-called brush border of syncytiotrophoblast villi, which is directly washed by maternal blood. Microvilli secrete placental alkaline phosphatase, which is a marker of transport processes and activates enzymes for many metabolic processes, participates in cell proliferation and tissue differentiation, carries out IgG transport to the fetus. The purpose of the work is to characterize the development of syncytiotrophoblast of the epithelium of the placenta villi at different dates of gestation during physiological pregnancy. To achieve the goal of the study, the tasks were set: 1. Study the dynamics of villi branching and the structure of the trophoblastic epithelium of villi from the stage of branched chorion to the end of pregnancy. 2. Determine the area of the trophoblastic epithelium of villi and study the immunohistochemical features of its main components using antibodies placental alkaline phosphatase, β – chorionic gonadotropin. 3. Study the dynamics of structural transformations and secretory activity of cyto- and syncytiotrophoblast at different gestational dates. Morphogenesis of syncytiotrophoblast of villous epithelium has been studied using histological, immunohistochemical and morphometric studies. The morphology of microvilli has been traced throughout the gestation period. The first forming microvilli were detected by 5 weeks; by 7 weeks, they were taller and flask-shaped; 8 weeks – had a branching structure; 9 weeks – non-branching structure, large and cylindrical; by the end of pregnancy (39-40 weeks) – rare, and there were no microvilli in the area of syncytio-capillary membranes. At 4-5 weeks, there is a weak degree of immunoexpression of β-hCG in the invasive cytotrophoblast and cytotrophoblastic epithelium and negative with the antibody against placental alkaline phosphatase. The area of the epithelium is 4,863.2 μm². At 6-7 weeks, the mean area of the villi is 19,705,5 μm². At 8-10 weeks, maximum epithelial area (6,370,7 μm²) and onset of placental alkaline phosphatase immunoexpression in the brush border area. In the period of 18-24 weeks, the area of villi decreases to 3,285,9 μm². At 39-40 weeks, terminal villi dominate with minimal values of the area of the trophoblastic epithelium, which is 786,2 μm². Syncytiocapillary membranes appear. A pronounced two-layer immunoexpression of placental alkaline phosphatase in the epithelium of all types of villi remains.

Relationship between EGFR inhibition in lung adenocarcinoma, cell surface expression of the placental antigen ALPP, and efficacy of ALPP-ADC therapy.

e15018 Background: In normal tissues placental alkaline phosphatases (ALPP) and ALPPL2 are exclusively expressed in the placenta. Their discovery in the cancer surfaceome has opened the possibility of targeting ALPP/ALPPL2. However, their low expression in most cancer types limits their therapeutic potential. In this study, we report a novel mechanism of ALPP upregulation in cancer cells that renders these cells more susceptible to ALPP-targeting therapies, which we evidence in the context of lung adenocarcinoma. Methods: Surface expression of ALPP and ALPPL2 was determined following biotinylation tagging of the cancer surfaceome, isolation of biotinylated proteins using monomeric avidin and mass spectrometry of the biotinylated trypsin digested fraction. ALPP antibody was conjugated with Monomethylauristatin F (ALPP-ADC-MMAF). For orthotopic xenograft models of LUAD were injected. For gefitinib treatment, Mice xenotransplanted with H1650 were treated with gefitinib (50mg/kg) daily for 10 days starting from Day 17 post cancer cell inoculation. For the gefitinib/ALPP-ADC combinational treatment, mice received anti-ALPP-MMAF (5mg/kg) at Day 19 and Day 26. Results: We assessed ALPP and ALPPL2 surfaceome protein levels in 158 cancer cell lines and their mRNA expression levels in 10,967 tumors representing 32 cancer types from The Cancer Genome Atlas (TCGA), which revealed ALPP, and to a lesser extent ALPPL2, to be variably expressed in several cancer types including lung adenocarcinoma (LUAD). We further confirmed surface expression of ALPP by tissue microarray analysis of 204 lung tumors. We report that treatment of LUAD cells with EGFR inhibitors or induction of cancer cell quiescence greatly enhanced ALPP surface expression. Mechanistically, repression of EGFR signaling resulted in activation of the transcription factor FoxO3a, which triggered expression of ALPP. Using xenograft models of LUAD, we further demonstrate that gefitinib treatment significantly upregulated surface expression of ALPP in LUAD tumors but not normal tissue. Combination therapy with gefitinib and an ALPP-ADC-MMAF resulted in superior anti-cancer efficacy compared with gefitinib or ALPP-ADC-MMAF alone. Conclusions: Our study provides mechanistic insights into ALPP upregulation in cancer cells and establishes FoxO3a as a transcriptional regulator of ALPP. Importantly, our findings have yielded a novel ‘two-hit’ combinational therapeutic strategy with enhanced ALPP targeting for greater efficacy.

Placenta-derived exosomes as carriers of non-coding RNAs in maternal circulation of patients with preeclampsia

ABSTRACT This study was conducted to illustrate the origin of these PE-related ncRNAs in maternal circulation and their underlying transport methods into target cells. We selected 10 women with severe pre-eclampsia (PE group) and 10 healthy participants who served as controls (NC group). Exosomes were isolated from their sera and their origin was determined by a specific marker, placental alkaline phosphatase (PLAP). We compared the ncrna associated with PE in exosomes and whole serum to observe the exchange of serum exosomes with trophoblast cells. The results showed that PLAP was enriched in the isolated exosomes. Seven PE-associated ncRNAs, including lnc-SNHG5, miR-26a-5p, miR-221-3p, miR-30a-3p, miR-18a, miR-152 and miR-155, were analyzed in placenta-derived exosomes and whole serum from both groups. miR-26a-5p, miR-152 and miR-155 were upregulated in the PE group compared with the NC group. 152 and miR-155 were upregulated. 152 and miR-155 were upregulated, while miR-18a and miR-221-3p were downregulated (P<0.05). ncRNAs were altered in serum and placenta-derived serum exosomes in a consistent trend. Fluorescence microscopy results showed that the nuclei were counterstained in HTR-8 cells exposed to PKH26-labeled exosomes. PE-associated ncRNAs can enter the maternal circulation through secretion and encapsulation into placenta-derived exosomes and participate in the development and progression of PE by targeting trophoblast cells. differential expression of ncRNAs in exosomes has the potential to be used as predictors for targeted therapy, providing new ideas and perspectives for improving maternal and infant outcomes.

Calcium-binding Cab45 regulates the polarized apical secretion of soluble proteins in epithelial cells.

Protein secretion is essential for epithelial tissue homoeostasis and therefore has to be tightly regulated. However, while the mechanisms regulating polarized protein sorting and trafficking have been widely studied in the past decade, those governing polarized secretion remain elusive. The calcium manganese pump SPCA1 and the calcium-binding protein Cab45 were recently shown to regulate the secretion of a subset of soluble cargoes in nonpolarized HeLa cells. Interestingly, we demonstrated that in polarized epithelial cells calcium levels in the trans-Golgi network (TGN), controlled by SPCA1, and Cab45 are critical for the apical sorting of glycosylphosphatidylinositol-anchored proteins (GPI-APs), a class of integral membrane proteins containing a soluble protein attached to the membrane by the GPI anchor, prompting us to investigate the mechanism regulating the polarized secretion of soluble cargoes. By reducing Cab45 expression level or overexpressing an inactive mutant of SPCA1, we found that Cab45 and calcium levels in the TGN drive the polarized apical secretion of a secretory form of placental alkaline phosphatase, exogenously expressed, and the endogenous soluble protein clusterin/Gp80 in Madin-Darby canine kidney (MDCK) cells. These data highlight the critical role of a calcium-dependent Cab45 mechanism regulating apical exocytosis in polarized MDCK cells.

Abstract LB011: Development of novel protein drug conjugates (PDCs) for the selective targeting of ALPP/ALPPL2 expressing tumors

Abstract The placental alkaline phosphatases, ALPP and ALPPL2, are glycosylphosphatidylinositol (GPI)-anchored cell-surface proteins that are expressed in the placenta during fetal development but have very little expression on normal adult tissue. These proteins are over-expressed in a number of different solid tumor indications including ovarian, endometrial, gastric, pancreatic and non-small cell lung cancers. As a result of the highly restricted normal tissue expression and over-expression in cancer, ALPP and ALPPL2 are attractive targets for antibody and protein-drug conjugate (ADC and PDC) approaches. The recent initiation of a Phase I clinical trial utilizing a full-length antibody ADC has fueled further interest in these oncology targets. Small protein domain binders, which have the capacity to penetrate deeper into solid tumors and can be engineered into multiple therapeutic formats in a modular fashion, offer a number of potential benefits over full-length antibodies as the targeting vehicle in PDC therapeutics. We report the identification and characterization of a series of high affinity ALPP/ALPPL2 specific single domain VHH binders which, importantly, show no binding to the closely related ALPI or ALPL isoforms (which have high normal tissue expression). Through application of the Almac Discovery PDC technology platform, these VHH domains have been reformatted into a suite of homogenous site-specifically labelled drug conjugates, with defined drug to antibody ratios, in high yields. These conjugates, which are based on mono- and bi-paratopic Fc fusion formats, employ both clinically established and novel linker-toxin combinations. In pre-clinical studies, the lead bi-paratopic PDCs were well tolerated in vivo and showed excellent anti-tumor efficacy in ALPP/ALPPL2 positive cell-line derived xenograft models of gastric and pancreatic carcinoma, with sustained regressions still observed 10 weeks after administration of the final dose of agent. These agents have physicochemical and pharmaceutical properties suitable for further development and we anticipate that the excellent pre-clinical efficacy profile of lead PDCs will translate to a highly differentiated product for the treatment of a variety of solid tumor indications. Citation Format: Graham Cotton, Paul Trumper, Estelle McLean, Mark Wappett, Stacey Bell, Greg Papadakos, Jennifer Thom, Chiara Saladino, Aaron Cranston, Georgiana Parau, Stephanie Gatdula, Stephanie Burton, Aidan McCann, Tim Harrison. Development of novel protein drug conjugates (PDCs) for the selective targeting of ALPP/ALPPL2 expressing tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB011.