PTEN Hamartoma Tumor Syndrome and Immune Dysregulation

Interleukin-1β: Friend or foe for gastrointestinal cancers

Gastrointestinal (GI) cancer is a malignancy arising in the digestive system and accounts for approximately a third of increasing global cancer-related mortality, especially in the colorectum, esophagus, stomach, and liver. Interleukin-1β (IL-1β) is a leukocytic pyrogen recognized as a tumor progression-related cytokine. IL-1β secretion and maturation in inflammatory responses could be regulated by nuclear factor-kappaB-dependent expression of NLR family pyrin domain containing 3, inflammasome formation, and activation of IL-1 converting enzyme. Several studies have documented the pro-tumorigenic effects of IL-1β in tumor microenvironments, promoting proliferation and metastatic potential of cancer cells in vitro and tumorigenesis in vivo. The application of IL-1β inhibitors is also promising for targeted therapy development in some cancer types. However, as a leukocytic pro-inflammatory cytokine, IL-1β may also possess anti-tumorigenic effects and be type-specific in different cancers. This editorial discusses the up-to-date roles of IL-1β in GI cancers, including underlying mechanisms and downstream signaling pathways. Understanding and clarifying the roles of IL-1β would significantly benefit future therapeutic targeting and help improve therapeutic outcomes in patients suffering from GI cancer.

Insights into Clinical Disorders in Cowden Syndrome: A Comprehensive Review

PTEN Hamartoma Tumour Syndrome (PHTS) encompasses diverse clinical phenotypes, including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), Proteus syndrome (PS), and Proteus-like syndrome. This autosomal dominant genetic predisposition with high penetrance arises from heterozygous germline variants in the PTEN tumour suppressor gene, leading to dysregulation of the PI3K/AKT/mTOR signalling pathway, which promotes the overgrowth of multiple and heterogenous tissue types. Clinical presentations of CS range from benign and malignant disorders, affecting nearly every system within the human body. CS is the most diagnosed syndrome among the PHTS group, notwithstanding its weak incidence (1:200,000), for which it is considered rare, and its precise incidence remains unknown among other important factors. The literature is notably inconsistent in reporting the frequencies and occurrences of these disorders, adding an element of bias and uncertainty when looking back at the available research. In this review, we aimed to highlight the significant disparities found in various studies concerning CS and to review the clinical manifestations encountered in CS patients. Furthermore, we intended to emphasize the great significance of early diagnosis as patients will benefit from a longer lifespan while being unceasingly advised and supported by a multidisciplinary team.

Genomic diversity in functionally relevant genes modifies neurodevelopmental versus neoplastic risks in individuals with germline PTEN variants

Individuals with germline PTEN variants (PHTS) have increased risks of the seemingly disparate phenotypes of cancer and neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD). Etiology of the phenotypic variability remains elusive. Here, we hypothesized that decreased genomic diversity, manifested by increased homozygosity, may be one etiology. Comprehensive analyses of 376 PHTS patients of European ancestry revealed significant enrichment of homozygous common variants in genes involved in inflammatory processes in the PHTS-NDD group and in genes involved in differentiation and chromatin structure regulation in the PHTS-ASD group. Pathway analysis revealed pathways germane to NDD/ASD, including neuroinflammation and synaptogenesis. Collapsing analysis of the homozygous variants identified suggestive modifier NDD/ASD genes. In contrast, we found enrichment of homozygous ultra-rare variants in genes modulating cell death in the PHTS-cancer group. Finally, homozygosity burden as a predictor of ASD versus cancer outcomes in our validated prediction model for NDD/ASD performed favorably.

PTEN hamartoma tumour syndrome: case report based on data from the Iranian hereditary colorectal cancer registry and literature review

BACKGROUND

PTEN hamartoma tumour syndrome (PHTS) is a rare hereditary disorder caused by germline pathogenic mutations in the PTEN gene. This study presents a case of PHTS referred for genetic evaluation due to multiple polyps in the rectosigmoid area, and provides a literature review of PHTS case reports published between March 2010 and March 2022.

CASE PRESENTATION

A 39-year-old Iranian female with a family history of gastric cancer in a first-degree relative presented with minimal bright red blood per rectum and resistant dyspepsia. Colonoscopy revealed the presence of over 20 polyps in the rectosigmoid area, while the rest of the colon appeared normal. Further upper endoscopy showed multiple small polyps in the stomach and duodenum, leading to a referral for genetic evaluation of hereditary colorectal polyposis. Whole-exome sequencing led to a PHTS diagnosis, even though the patient displayed no clinical or skin symptoms of the condition. Further screenings identified early-stage breast cancer and benign thyroid nodules through mammography and thyroid ultrasound.

METHOD AND RESULTS OF LITERATURE REVIEW

A search of PubMed using the search terms "Hamartoma syndrome, Multiple" [Mesh] AND "case report" OR "case series" yielded 43 case reports, predominantly in women with a median age of 39 years. The literature suggests that patients with PHTS often have a family history of breast, thyroid and endometrial neoplasms along with pathogenic variants in the PTEN/MMAC1 gene. Gastrointestinal polyps are one of the most common signs reported in the literature, and the presence of acral keratosis, trichilemmomas and mucocutaneous papillomas are pathognomonic characteristics of PHTS.

CONCLUSION

When a patient presents with more than 20 rectosigmoid polyps, PHTS should be considered. In such cases, it is recommended to conduct further investigations to identify other potential manifestations and the phenotype of PHTS. Women with PHTS should undergo annual mammography and magnetic resonance testing for breast cancer screening from the age of 30, in addition to annual transvaginal ultrasounds and blind suction endometrial biopsies.

The PTEN hamartoma tumor syndrome: how oral clinicians may save lives

INTRODUCTION

Patients with the PTEN hamartoma tumor syndrome (PHTS) have an 81%-90% cumulative lifetime risk of developing cancer. Around 90% of these patients have recognizable oral features. Receiving a diagnosis may save these patients' lives. This is the first presentation of a family with the PHTS diagnosis with focus on the oral and periodontal findings and treatments.

CASE PRESENTATION

All three children (one son and two daughters) inherited the same heterozygous variant in the PTEN gene from their father. Gingival overgrowth was observed in all patients in addition to macrocephaly. Other findings included fissured tongue, high arched palate, papules, and trichilemmomas. The father had experienced severe tooth loss. Surgery was performed to treat the gingival overgrowth and periodontal pockets; however, the treatment was characterized by multiple recurrences of the overgrowth.

CONCLUSIONS

Oral changes, macrocephaly, tumors, and/or a family history of benign or malignant lesions are important features that oral clinicians should be aware of for a possible PHTS diagnosis. Patients suspected of having PHTS should be referred to a medical practitioner, specifically a geneticist, for further diagnostic investigations. The periodontal problems seemed to be difficult to control for these patients. They will likely need an active and frequent maintenance therapy to control the persistent inflammation and gingival overgrowth. In addition, they need a thorough monitoring for benign or malignant changes in the orofacial regions. Why are these cases new information? Oral features are found in 90% of the cases with the PHTS diagnosis. The periodontal findings showed a persistent recurrence of gingival overgrowth with a strong probability of serious periodontal diseases. What are the keys to successful management of these cases? A suspicion of a PHTS diagnosis with a referral to a medical practitioner, specifically a geneticist, for complete workup may help save these patients' lives. Close monitoring during maintenance therapy with re-treatment as needed to prevent further periodontal complications. Continued monitoring and treatment throughout the patient's lifetime for development of recurrent or new, benign or malignant lesions at relevant sites. What are the primary limitations to success in these cases? A failure to identify the PHTS syndrome with the accompanying oral and periodontal complications. Complications may lead to a delay in appropriate treatment. Inability to control the persistent gingival overgrowth and a deteriorating periodontal condition. A failure to discover benign and malignant lesions in the orofacial region.

Hereditary cancer syndromes

Hereditary cancer syndromes (HCSs) are arguably the most frequent category of Mendelian genetic diseases, as at least 2% of presumably healthy subjects carry highly-penetrant tumor-predisposing pathogenic variants (PVs). Hereditary breast-ovarian cancer and Lynch syndrome make the highest contribution to cancer morbidity; in addition, there are several dozen less frequent types of familial tumors. The development of the majority albeit not all hereditary malignancies involves two-hit mechanism, i.e. the somatic inactivation of the remaining copy of the affected gene. Earlier studies on cancer families suggested nearly fatal penetrance for the majority of HCS genes; however, population-based investigations and especially large-scale next-generation sequencing data sets demonstrate that the presence of some highly-penetrant PVs is often compatible with healthy status. Hereditary cancer research initially focused mainly on cancer detection and prevention. Recent studies identified multiple HCS-specific drug vulnerabilities, which translated into the development of highly efficient therapeutic options.

Fibro-Adipose Vascular Anomaly: Characteristic Imaging Features on Sonography and Magnetic Resonance Imaging

OBJECTIVE

To analyse the image characteristics of fibro-adipose vascular anomaly (FAVA) and the value of ultrasound and magnetic resonance imaging (MRI) for its diagnosis.

METHODS

The clinical and imaging data characteristics of 10 patients with FAVA admitted to our hospital between January 2018 and December 2020 who underwent ultrasound and MRI diagnosis were retrospectively analysed.

RESULTS

A total of 10 patients (six males and four females) with pathologically confirmed FAVA, aged from 3 to 27 years (median: 13 years), underwent ultrasound and MRI; of these, two patients underwent MRI-enhanced examinations. All lesions involved mainly muscle, with a few disruptions and involvements of subcutaneous fat. Five cases were located subcutaneously near the fascia; one case was adjacent to the periosteum. Ultrasound showed fascial tail in seven cases, and MRI showed fascial tail in six cases. Both ultrasound and MRI showed the lesions to be oval-shaped masses with blurred borders and a mean maximum diameter of 99.8 ± 48.7 mm. Ultrasound showed a mass with a mixture of high and low echoic areas. Magnetic resonance imaging imaging showed a heterogeneous, mixed-signal intensity on T1-weighted images, probably influenced by the fibrous and fatty components of the lesion. T2-weighted images showed a mixed-high signal. Enhanced computed tomography scans showed significant heterogeneous enhancement of the lesions.

CONCLUSION

Both ultrasound and MRI showed that fascial tail sign is an important imaging feature for FAVA disease; this provides a reliable basis for its diagnosis and can be used to distinguish it from venous malformations, which have no fascial tail signs. Therefore, fascial tail signs can be used as imaging features and require special attention in the diagnosis of FAVA disease.

Polyene phosphatidylcholine ameliorates synovial inflammation: involvement of PTEN elevation and glycolysis suppression

BACKGROUND

Synovial inflammation, characterized by the activation of synovial fibroblasts (SFs), is a crucial factor to drive the progression of rheumatoid arthritis (RA). Polyene phosphatidylcholine (PPC), the classic hepatoprotective drug, has been reported to ameliorate arthritis in animals. However, the molecular mechanism remains poorly understood. METHODS AND RESULTS: Using in vitro primary synovial fibroblast (SFs) culture system, we revealed that phosphatase and tension homolog deleted on chromosome 10 (PTEN), a tumor suppressor, mediates the anti-inflammatory effect of PPC in lipopolysaccharide (LPS)-stimulated primary SFs. PPC decreased the production of TNF-α and IL-6 production while elevating the level of IL-10 and TGF-β. Furthermore, PPC up-regulated the expression of PTEN, but inhibited the expression of p-AKT (ser473) and PI3K-p85α. Moreover, pre-treatment of SF1670 (the inhibitor of PTEN) or 740Y-P (the agonist of AKT/PI3K pathways) partially abrogated the anti-inflammatory effect of PPC. In addition, PPC could inhibit the expression of GLUT4, a key transporter of glucose that fuels the glycolysis, which is accompanied by the expression downregualtion of glycolytic enzymes PFKFB3 and PKM2. Furthermore, PPC could reduce ROS production and mitochondrial membrane potential in LPS-stimulated SFs and MH7A cell line.

CONCLUSION

The present study supported that PPC can alleviate synovial inflammation, which involves in the elevation of PTEN and blockage of glycolysis.

Polygenic autoimmune disease risk alleles impacting B cell tolerance act in concert across shared molecular networks in mouse and in humans

Most B cells produced in the bone marrow have some level of autoreactivity. Despite efforts of central tolerance to eliminate these cells, many escape to periphery, where in healthy individuals, they are rendered functionally non-responsive to restimulation through their antigen receptor via a process termed anergy. Broad repertoire autoreactivity may reflect the chances of generating autoreactivity by stochastic use of germline immunoglobulin gene segments or active mechanisms may select autoreactive cells during egress to the naïve peripheral B cell pool. Likewise, it is unclear why in some individuals autoreactive B cell clones become activated and drive pathophysiologic changes in autoimmune diseases. Both of these remain central questions in the study of the immune system(s). In most individuals, autoimmune diseases arise from complex interplay of genetic risk factors and environmental influences. Advances in genome sequencing and increased statistical power from large autoimmune disease cohorts has led to identification of more than 200 autoimmune disease risk loci. It has been observed that autoantibodies are detectable in the serum years to decades prior to the diagnosis of autoimmune disease. Thus, current models hold that genetic defects in the pathways that control autoreactive B cell tolerance set genetic liability thresholds across multiple autoimmune diseases. Despite the fact these seminal concepts were developed in animal (especially murine) models of autoimmune disease, some perceive a disconnect between human risk alleles and those identified in murine models of autoimmune disease. Here, we synthesize the current state of the art in our understanding of human risk alleles in two prototypical autoimmune diseases – systemic lupus erythematosus (SLE) and type 1 diabetes (T1D) along with spontaneous murine disease models. We compare these risk networks to those reported in murine models of these diseases, focusing on pathways relevant to anergy and central tolerance. We highlight some differences between murine and human environmental and genetic factors that may impact autoimmune disease development and expression and may, in turn, explain some of this discrepancy. Finally, we show that there is substantial overlap between the molecular networks that define these disease states across species. Our synthesis and analysis of the current state of the field are consistent with the idea that the same molecular networks are perturbed in murine and human autoimmune disease. Based on these analyses, we anticipate that murine autoimmune disease models will continue to yield novel insights into how best to diagnose, prognose, prevent and treat human autoimmune diseases.

Phosphatidylinositol 3-kinase signaling and immune regulation: insights into disease pathogenesis and clinical implications

INTRODUCTION

Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that plays a fundamental role in cell survival, metabolism, proliferation and differentiation. Thus, balanced PI3K signalling is critical for multiple aspects of human health. The discovery that germline variants in genes in the PI3K pathway caused inborn errors of immunity highlighted the non-redundant role of these signalling proteins in the human immune system. The subsequent identification and characterisation of >300 individuals with a novel immune dysregulatory disorder, termed activated PI3K-delta syndrome (APDS), has reinforced the status of PI3K as a key pathway regulating immune function. Studies of APDS have demonstrated that dysregulated PI3K function is disruptive for immune cell development, activation, differentiation, effector function and self-tolerance, which are all important in supporting effective, long-term immune responses.

AREAS COVERED

In this review, we recount recent findings regarding humans with germline variants in PI3K genes and discuss the underlying cellular and molecular pathologies, with a focus on implications for therapy in APDS patients.

EXPERT OPINION

Modulating PI3K immune cell signalling by offers opportunities for therapeutic interventions in settings of immunodeficiency, autoimmunity and malignancy, but also highlights potential adverse events that may result from overt pharmacological or intrinsic inhibition of PI3K function.

Two Monogenetic Disorders, Activated PI3-Kinase-δ Syndrome 2 and Smith-Magenis Syndrome, in One Patient: Case Report and a Literature Review of Neurodevelopmental Impact in Primary Immunodeficiencies Associated With Disturbed PI3K Signaling

Activated PI3-kinase-δ syndrome 2 (APDS2) is caused by autosomal dominant mutations in the PIK3R1 gene encoding the p85α, p55α, and p50α regulatory subunits. Most diagnosed APDS2 patients carry mutations affecting either the splice donor or splice acceptor sites of exon 11 of the PIK3R1 gene responsible for an alternative splice product and a shortened protein. The clinical presentation of APDS2 patients is highly variable, ranging from mild to profound combined immunodeficiency features as massive lymphoproliferation, increased susceptibility to bacterial and viral infections, bronchiectasis, autoimmune manifestations, and occurrence of cancer. Non-immunological features such as growth retardation and neurodevelopmental delay have been reported for APDS2 patients. Here, we describe a patient suffering from an APDS2 associated with a Smith-Magenis syndrome (SMS), a complex genetic disorder affecting, among others, neurological manifestations and review the literature describing neurodevelopmental impacts in APDS2 and other PIDs/monogenetic disorders associated with dysregulated PI3K signaling.

Lymphadenopathy at the crossroad between immunodeficiency and autoinflammation: An intriguing challenge

Lymphadenopathies can be part of the clinical spectrum of several primary immunodeficiencies, including diseases with immune dysregulation and autoinflammatory disorders, as the clinical expression of benign polyclonal lymphoproliferation, granulomatous disease or lymphoid malignancy. Lymphadenopathy poses a significant diagnostic dilemma when it represents the first sign of a disorder of the immune system, leading to a consequently delayed diagnosis. Additionally, the finding of lymphadenopathy in a patient with diagnosed immunodeficiency raises the question of the differential diagnosis between benign lymphoproliferation and malignancies. Lymphadenopathies are evidenced in 15–20% of the patients with common variable immunodeficiency, while in other antibody deficiencies the prevalence is lower. They are also evidenced in different combined immunodeficiency disorders, including Omenn syndrome, which presents in the first months of life. Interestingly, in the activated phosphoinositide 3‐kinase delta syndrome, autoimmune lymphoproliferative syndrome, Epstein–Barr virus (EBV)‐related lymphoproliferative disorders and regulatory T cell disorders, lymphadenopathy is one of the leading signs of the entire clinical picture. Among autoinflammatory diseases, the highest prevalence of lymphadenopathies is observed in patients with periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) and hyper‐immunoglobulin (Ig)D syndrome. The mechanisms underlying lymphoproliferation in the different disorders of the immune system are multiple and not completely elucidated. The advances in genetic techniques provide the opportunity of identifying new monogenic disorders, allowing genotype–phenotype correlations to be made and to provide adequate follow‐up and treatment in the single diseases. In this work, we provide an overview of the most relevant immune disorders associated with lymphadenopathy, focusing on their diagnostic and prognostic implications.

Selected Topics in the Pathology of the Thyroid and Parathyroid Glands in Children and Adolescents

The goals of this chapter in keeping with the overall general themes of this special edition will be (1) to highlight aspects of development of the thyroid and parathyroid glands with particular focus on the role and contribution of the neural crest (or not) and how this may impact on the pathology that is seen, (2) to emphasize those lesions particularly more commonly arising in the pediatric population that actually generate specimens that the surgical pathologist would encounter, and (3) highlight more in depth specific lesions associated with heritable syndromes or specific gene mutations since the heritable syndromes tends to manifest in the pediatric age group. In this light, the other interesting areas of pediatric thyroid disease including medical thyroid diseases, congenital hypothyroidism, anatomic variants and aberrations of development that lead to structural anomalies will not be emphasized here.

Interplay Between Class II HLA Genotypes and the Microbiome and Immune Phenotypes in Individuals With PTEN Hamartoma Tumor Syndrome

We evaluate potential contributors to the development of autoimmunity and other phenotypes consistent with immune dysregulation in individuals with germline mutations in the tumor suppressor gene PTEN in this observational report.

MATERIALS AND METHODS

Illumina sequencing of bacterial and fungal microbes was carried out on patient-donated fecal samples in a cohort of 67 patients with pathogenic germline PTEN mutations, including 41 individuals with autoimmunity and/or phenotypes consistent with immune dysregulation (cases) and 26 individuals without (controls). From these data, we measured differences in alpha and beta diversity between cases and controls and identified differentially abundant bacterial and fungal taxa using phyloseq and MicrobiomeSeq packages in R. We analyzed correlations between these taxa and specific HLA genotypes, along with correlations between HLA diversity and microbial diversity, by conducting high-resolution HLA genotyping at four class II loci (DRB1, DRB345, DQA1, and DQB1).

RESULTS

We found that alpha diversity distributions for both bacterial and fungal genera were statistically different between cases and controls. We identified differentially abundant bacterial and fungal taxa between cases and controls. Network analysis of differentially abundant bacterial taxa revealed some co-varying bacterial genera. We additionally found significant correlations between certain HLA genotypes and certain taxa and significant correlations between HLA diversity and alpha diversity.

CONCLUSION

PTEN-associated immune phenotypes might be influenced by the gut microbiome, and class II HLA molecules, in part, crosstalk with the gut microbiome. These preliminary observations should lay the groundwork for future studies to ultimately derive clinical measures, which could use gut microbiome and HLA molecule biomarkers to predict, and perhaps prevent, immunity and inflammation in patients predisposed to cancer because of germline PTEN mutations.

Disorders Related to PI3Kδ Hyperactivation: Characterizing the Clinical and Immunological Features of Activated PI3-Kinase Delta Syndromes

Phosphoinositide-3-kinase δ (PI3Kδ) is found in immune cells and is part of the PI3K/AKT/mTOR/S6K signalling pathway essential to cell survival, growth and differentiation. Hyperactivation of PI3Kδ enzyme results in Activated PI3-kinase delta syndrome (APDS). This childhood onset, autosomal dominant, combined immunodeficiency, is caused by heterozygous gain of function (GOF) mutations in PIK3CD (encodes PI3Kδ catalytic subunit p110δ), mutations in PIK3R1 (encodes PI3Kδ regulatory subunit p85α) or LOF mutations in PTEN (terminates PI3Kδ signalling) leading to APDS1, APDS2 and APDS-Like (APDS-L), respectively. APDS was initially described in 2013 and over 285 cases have now been reported. Prompt diagnosis of APDS is beneficial as targeted pharmacological therapies such as sirolimus and potentially PI3Kδ inhibitors can be administered. In this review, we provide an update on the clinical and laboratory features of this primary immunodeficiency. We discuss the common manifestations such as sinopulmonary infections, bronchiectasis, lymphoproliferation, susceptibility to herpesvirus, malignancy, as well as more rare non-immune features such as short stature and neurodevelopmental abnormalities. Laboratory characteristics, such as antibody deficiency and B cell and T cell, phenotypes are also summarised.

The prognostic roles of hypogammaglobulinemia and hypocomplementemia in newly diagnosed diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most frequent type of lymphoma. Our retrospective study included 553 newly diagnosed DLBCL patients from May 2009 to October 2019. The relationships between hypogammaglobulinemia, hypocomplementemia and progression-free survival (PFS) and overall survival (OS) were assessed. In our center, 19.0% of patients had hypogammaglobulinemia, and 7.7% had hypocomplementemia at diagnosis. Immunoglobulin and complement deficiencies were associated with advanced disease and displayed inferior PFS and OS. Then, we designed a new immunization cumulative prognostic score (ICPS) model to comprehensively clarify the effect of these two variables on prognosis. Multivariate analysis showed that ICPS was an independent prognostic indicator for inferior clinical outcomes (PFS: p = 0.007, OS: p = 0.003). Furthermore, the predictive effect of ICPS combined with the International Prognostic Index (IPI) was superior to that of IPI alone (PFS: p = 0.016, OS: p = 0.037). In conclusion, hypogammaglobulinemia and hypocomplementemia could be regarded as adverse prognostic indicators in DLBCL.

Control of T lymphocyte fate decisions by PI3K signaling

Virtually all aspects of T and B lymphocyte development, homeostasis, activation, and effector function are impacted by the interaction of their clonally distributed antigen receptors with antigens encountered in their respective environments. Antigen receptors mediate their effects by modulating intracellular signaling pathways that ultimately impinge on the cytoskeleton, bioenergetic pathways, transcription, and translation. Although these signaling pathways are rather well described at this point, especially those steps that are most receptor-proximal, how such pathways contribute to more quantitative aspects of lymphocyte function is still being elucidated. One of the signaling pathways that appears to be involved in this “tuning” process is controlled by the lipid kinase PI3K. Here we review recent key findings regarding both the triggering/enhancement of PI3K signals (via BCAP and ICOS) as well as their regulation (via PIK3IP1 and PHLPP) and how these signals integrate and determine cellular processes. Lymphocytes display tremendous functional plasticity, adjusting their metabolism and gene expression programs to specific conditions depending on their tissue of residence and the nature of the infectious threat to which they are responding. We give an overview of recent findings that have contributed to this model, with a focus on T cells, including what has been learned from patients with gain-of-function mutations in PI3K as well as lessons from cancer immunotherapy approaches.

Germline PTEN mutations are associated with a skewed peripheral immune repertoire in humans and mice

Individuals with germline mutations in the gene encoding phosphatase and tensin homolog on chromosome ten (PTEN) are diagnosed with PTEN hamartoma tumor syndrome (PHTS) and are at high risk for developing breast, thyroid and other cancers and/or autoimmunity or neurodevelopmental issues including autism spectrum disorders. Although well recognized as a tumor suppressor, involvement of PTEN mutations in mediating such a diverse range of phenotypes indicates a more central involvement for PTEN in immunity than previously recognized. To address this, sequencing of the T-cell receptor variable-region β-chain was performed on peripheral blood from PHTS patients. Based on patient findings, we performed mechanistic studies in two Pten knock-in murine models, distinct from each other in cell compartment-specific predominance of Pten. We found that PTEN mutations in humans and mice are associated with a skewed T- and B-cell gene repertoire, characterized by increased prevalence of high-frequency clones. Immunological characterization showed that Pten mutants have increased B-cell proliferation and a proclivity towards increased T-cell reactivity upon Toll-like-receptor stimulation. Furthermore, decreases in nuclear but not cytoplasmic Pten levels associated with a reduction in expression of the autoimmune regulator (Aire), a critical mediator of central immune tolerance. Mechanistically, we show that nuclear PTEN most likely regulates Aire expression via its emerging role in splicing regulation. We conclude that germline disruption of PTEN, both in human and mouse, results in compromised central immune tolerance processes that may significantly impact individual stress responses and therefore predisposition to autoimmunity and cancer.

PTEN Function at the Interface between Cancer and Tumor Microenvironment: Implications for Response to Immunotherapy

Mounting preclinical and clinical evidence indicates that rewiring the host immune system in favor of an antitumor microenvironment achieves remarkable clinical efficacy in the treatment of many hematological and solid cancer patients. Nevertheless, despite the promising development of many new and interesting therapeutic strategies, many of these still fail from a clinical point of view, probably due to the lack of prognostic and predictive biomarkers. In that respect, several data shed new light on the role of the tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN) in affecting the composition and function of the tumor microenvironment (TME) as well as resistance/sensitivity to immunotherapy. In this review, we summarize current knowledge on PTEN functions in different TME compartments (immune and stromal cells) and how they can modulate sensitivity/resistance to different immunological manipulations and ultimately influence clinical response to cancer immunotherapy.

PI3K pathway defects leading to immunodeficiency and immune dysregulation

The phosphatidylinositol 3-kinase (PI3K) signaling pathway is involved in a broad range of cellular processes, including growth, metabolism, differentiation, proliferation, motility, and survival. The PI3Kδ enzyme complex is primarily present in the immune system and comprises a catalytic (p110δ) and regulatory (p85α) subunit. Dynamic regulation of PI3Kδ activity is required to ensure normal function and differentiation of immune cells. In the last decade, discovery of germline mutations in genes involved in the PI3Kδ pathway (PIK3CD, PIK3R1, or phosphatase and tensin homolog [PTEN]) proved that both overactivation and underactivation (gain of function and loss of function, respectively) of PI3Kδ lead to impaired and dysregulated immunity. Although a small group of patients reported to underactivate PI3Kδ show predominantly humoral defects and autoimmune features, more than 200 patients have been described with overactivation of PI3Kδ, presenting with a much more complex phenotype of combined immunodeficiency and immune dysregulation. The clinical and immunologic characterization, as well as current pathophysiologic understanding and specific therapies for PI3K pathway defects leading to immunodeficiency and immune dysregulation, are reviewed here.

Heterogeneity of Liver Disease in Common Variable Immunodeficiency Disorders

Common variable immunodeficiency (CVID) is the most frequent primary immunodeficiency (PID) in adulthood and is characterized by severe reduction of immunoglobulin serum levels and impaired antibody production in response to vaccines and pathogens. Beyond the susceptibility to infections, CVID encompasses a wide spectrum of clinical manifestations related to a complex immune dysregulation that also affects liver. Although about 50% CVID patients present persistently deranged liver function, burden, and nature of liver involvement have not been systematically investigated in most cohort studies published in the last decades. Therefore, the prevalence of liver disease in CVID widely varies depending on the study design and the sampling criteria. This review seeks to summarize the evidence about the most relevant causes of liver involvement in CVID, including nodular regenerative hyperplasia (NRH), infections and malignancies. We also describe the clinical features of liver disease in some monogenic forms of PID included in the clinical spectrum of CVID as ICOS, NFKB1, NFKB2, CTLA-4, PI3Kδ pathway, ADA2, and IL21-R genetic defects. Finally, we discuss the clinical applications of the various diagnostic tools and the possible therapeutic approaches for the management of liver involvement in the context of CVID.

Transcriptomic Analysis of Cellular Pathways in Healing Flexor Tendons of Plasminogen Activator Inhibitor 1 (PAI-1/Serpine1) Null Mice

Injuries to flexor tendons can be complicated by fibrotic adhesions, which severely impair the function of the hand. Plasminogen activator inhibitor 1 (PAI-1/SERPINE1), a master suppressor of fibrinolysis and protease activity, is associated with adhesions. Here, we used next-generation RNA sequencing (RNA-Seq) to assess genome-wide differences in messenger RNA expression due to PAI-1 deficiency after zone II flexor tendon injury. We used the ingenuity pathway analysis to characterize molecular pathways and biological drivers associated with differentially expressed genes (DEG). Analysis of hundreds of overlapping and DEG in PAI-1 knockout (KO) and wild-type mice (C57Bl/6J) during tendon healing revealed common and distinct biological processes. Pathway analysis identified cell proliferation, survival, and senescence, as well as chronic inflammation as potential drivers of fibrotic healing and adhesions in injured tendons. Importantly, we identified the activation of PTEN signaling and the inhibition of FOXO1-associated biological processes as unique transcriptional signatures of the healing tendon in the PAI-1/Serpine1 KO mice. Further, transcriptomic differences due to the genetic deletion of PAI-1 were mechanistically linked to PI3K/Akt/mTOR, PKC, and MAPK signaling cascades. These transcriptional observations provide novel insights into the biological roles of PAI-1 in tendon healing and could identify therapeutic targets to achieve scar-free regenerative healing of tendons. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:43-58, 2020.

The Role of PTEN in Innate and Adaptive Immunity

The lipid and protein phosphatase and tensin homolog (PTEN) controls the differentiation and activation of multiple immune cells. PTEN acts downstream from T- and B-cell receptors, costimulatory molecules, cytokine receptors, integrins, and also growth factor receptors. Loss of PTEN activity in human and mice is associated with cellular and humoral immune dysfunction, lymphoid hyperplasia, and autoimmunity. Although most patients with PTEN hamartoma tumor syndrome (PHTS) have no immunological symptoms, a subclinical immune dysfunction is present in many, and clinical immunodeficiency in few. Comparison of the immune phenotype caused by PTEN haploinsufficiency in PHTS, phosphoinositide 3-kinase (PI3K) gain-of-function in activated PI3K syndrome, and mice with conditional biallelic Pten deletion suggests a threshold model in which coordinated activity of several phosphatases control the PI3K signaling in a cell-type-specific manner. Emerging evidence highlights the role of PTEN in polygenic autoimmune disorders, infection, and the immunological response to cancer. Targeting the PI3K axis is an emerging therapeutic avenue.

Exosome-Mediated MiR-155 Transfer Contributes to Hepatocellular Carcinoma Cell Proliferation by Targeting PTEN

BACKGROUND Most eukaryocytes release nano vesicles (30-120 nm), named exosomes, to various biological fluids such as blood, lymph, and milk. Hepatocellular carcinoma (HCC) is one of the tumors with the highest incidence rate in primary malignant carcinoma of the liver. However, the mechanism of HCC proliferation remains elusive. In this study, we aim to explore whether HCC cell-derived exosomes affect the proliferation of cancer cells. MATERIAL AND METHODS Exosomes were isolated from HCC cells by ultracentrifugation and were visualized the phenotype by transmission electron microscopy. Cell proliferation was detected by Cell Counting Kit-8 assays and EdU (5-ethynyl-2-deoxyuridine) incorporation assays. Dual-luciferase assays were performed to validate the paired correlation of miR-155 and 3'-UTR of PTEN (gene of phosphate and tension homology deleted on chromosome 10). A xenograft mice model was constructed to verify the effect of exosome-mediated miR-155 on cell proliferation in vivo. RESULTS Our finding showed that miR-155 was enriched in exosomes released from HCC cells. The exosome-containing miR-155 transferred into new HCC targeted cells and lead to the elevation of HCC cells' proliferation. Besides, the exosomal miR-155 directly bound to 3'-UTR of PTEN leading to the reduction of relevant targets in recipient liver cells. The knockdown of PTEN attenuated the proliferation of HCC cells treated with the exosomal miR-155. Moreover, nude-mouse experiment results revealed a promotional effect of the exosomal miR-155 on HCC cell-acquired xenografts. CONCLUSIONS Our study indicated that exosomal-specific miR-155 transfers to adjacent and/or more distant cells and stimulates the proliferation of HCC cells.

PTEN Hamartoma tumor syndrome in childhood: A review of the clinical literature

PTEN hamartoma tumor syndrome (PHTS) is a highly variable autosomal dominant condition associated with intellectual disability, overgrowth, and tumor predisposition phenotypes, which often overlap. PHTS incorporates a number of historical clinical presentations including Bannayan-Riley-Ruvalcaba syndrome, Cowden syndrome, and a macrocephaly-autism/developmental delay syndrome. Many reviews in the literature focus on PHTS as an adult hamartoma and malignancy predisposition condition. Here, we review the current literature with a focus on pediatric presentations. The review starts with a summary of the main conditions encompassed within PHTS. We then discuss PHTS diagnostic criteria, and clinical features. We briefly address rarer PTEN associations, and the possible role of mTOR inhibitors in treatment. We acknowledge the limited understanding of the natural history of childhood-onset PHTS as a cancer predisposition syndrome and present a summary of important management considerations.

Revising PTEN in the Era of Immunotherapy: New Perspectives for an Old Story

Immunotherapy has emerged as the new therapeutic frontier of cancer treatment, showing enormous survival benefits in multiple tumor diseases. Although undeniable success has been observed in clinical trials, not all patients respond to treatment. Different concurrent conditions can attenuate or completely abrogate the usefulness of immunotherapy due to the activation of several escape mechanisms. Indeed, the tumor microenvironment has an almost full immunosuppressive profile, creating an obstacle to therapeutic treatment. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) governs a plethora of cellular processes, including maintenance of genomic stability, cell survival/apoptosis, migration, and metabolism. The repertoire of PTEN functions has recently been expanded to include regulation of the tumor microenvironment and immune system, leading to a drastic reevaluation of the canonical paradigm of PTEN action with new potential implications for immunotherapy-based approaches. Understanding the implication of PTEN in cancer immunoediting and immune evasion is crucial to develop new cancer intervention strategies. Recent evidence has shown a double context-dependent role of PTEN in anticancer immunity. Here we summarize the current knowledge of PTEN’s role at a crossroads between tumor and immune compartments, highlighting the most recent findings that are likely to change future clinical practice.

Phosphoinositide 3-Kinase Signaling Can Modulate MHC Class I and II Expression

Molecular events activating the PI3K pathway are frequently detected in human tumors and the activation of PI3K signaling alters numerous cellular processes including tumor cell proliferation, survival, and motility. More recent studies have highlighted the impact of PI3K signaling on the cellular response to interferons and other immunologic processes relevant to antitumor immunity. Given the ability of IFNγ to regulate antigen processing and presentation and the pivotal role of MHC class I (MHCI) and II (MHCII) expression in T-cell-mediated antitumor immunity, we sought to determine the impact of PI3K signaling on MHCI and MHCII induction by IFNγ. We found that the induction of cell surface MHCI and MHCII molecules by IFNγ is enhanced by the clinical grade PI3K inhibitors dactolisib and pictilisib. We also found that PI3K inhibition increases STAT1 protein levels following IFNγ treatment and increases accessibility at genomic STAT1-binding motifs. Conversely, we found that pharmacologic activation of PI3K signaling can repress the induction of MHCI and MHCII molecules by IFNγ, and likewise, the loss of PTEN attenuates the induction of MHCI, MHCII, and STAT1 by IFNγ. Consistent with these in vitro studies, we found that within human head and neck squamous cell carcinomas, intratumoral regions with high phospho-AKT IHC staining had reduced MHCI IHC staining. IMPLICATIONS: Collectively, these findings demonstrate that MHC expression can be modulated by PI3K signaling and suggest that activation of PI3K signaling may promote immune escape via effects on antigen presentation.

Whole exome sequencing in childhood-onset lupus frequently detects single gene etiologies

BACKGROUND

Systemic lupus erythematosus (SLE) comprise a diverse range of clinical manifestations. To date, more than 30 single gene causes of lupus/lupus like syndromes in humans have been identified. In the clinical setting, identifying the underlying molecular diagnosis is challenging due to phenotypic and genetic heterogeneity.

METHODS

We employed whole exome sequencing (WES) in patients presenting with childhood-onset lupus with severe and/or atypical presentations to identify cases that are explained by a single-gene (monogenic) cause.

RESULTS

From January 2015 to June 2018 15 new cases of childhood-onset SLE were diagnosed in Edmond and Lily Safra Children's Hospital. By WES we identified causative mutations in four subjects in five different genes: C1QC, SLC7A7, MAN2B1, PTEN and STAT1. No molecular diagnoses were established on clinical grounds prior to genetic testing.

CONCLUSIONS

We identified a significant fraction of monogenic SLE etiologies using WES and confirm the genetic locus heterogeneity in childhood-onset lupus. These results highlight the importance of establishing a genetic diagnosis for children with severe or atypical lupus by providing accurate and early etiology-based diagnoses and improving subsequent clinical management.

PTEN Hamartoma Tumor Syndrome: A Clinical Overview

The phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is a grouping of related genetic disorders that has been linked to germline mutations in the PTEN gene. These disorders include Cowden syndrome (CS), Bannayan–Riley–Ruvalcaba syndrome, adult Lhermitte–Duclos disease, and autism spectrum disorders associated with macrocephaly. The majority of the clinical information available on PHTS, however, is related to individuals diagnosed with CS. There is still much to be learned about this disorder, since diagnostic criteria for CS were only established in 1996, before the identification of the PTEN gene, and were based primarily on features seen in cases reported in the existing literature. More recently, however, data from several large series of patients have shown that a number of the clinical features associated with PTEN mutations are either more or less common than previously reported. In addition, we now know that only about 30–35% of patients meeting clinical diagnostic criteria for Cowden syndrome actually have a detectable PTEN mutation. Thus, our understanding of PTEN-related diseases and their management has evolved significantly over time. The United States National Comprehensive Cancer Network (NCCN) has produced and regularly updates practice guidelines which include clinical diagnostic criteria as well as guidelines for PTEN testing and management of patients with mutations. This review will summarize the overall literature on PHTS as well as recent findings which are broadening our understanding of this set of disorders.