The Lymphangioleiomyomatosis Lung Cell and Its Human Cell Models

Sorafenib inhibits invasion of multicellular organoids that mimic Lymphangioleiomyomatosis nodules

Lymphangioleiomyomatosis (LAM) is a debilitating, progressive lung disease with few therapeutic options, largely due to a paucity of mechanistic knowledge of disease pathogenesis. Lymphatic endothelial cells (LECs) are known to envelope and invade clusters of LAM-cells, comprising of smooth muscle α-actin and/or HMB-45 positive "smooth muscle-like cells" however the role of LECs in LAM pathogenesis is still unknown. To address this critical knowledge gap, we investigated wether LECs interact with LAM-cells to augment their metastatic behaviour of LAM-cells. We performed in situ spatialomics and identified a core of transcriptomically related cells within the LAM nodules. Pathway analysis highlights wound and pulmonary healing, VEGF signaling, extracellular matrix/actin cytoskeletal regulating and the HOTAIR regulatory pathway enriched in the LAM Core cells. We developed an organoid co-culture model combining primary LAM-cells with LECs and applied this to evaluate invasion, migration, and the impact of Sorafenib, a multi-kinase inhibitor. LAM-LEC organoids had significantly higher extracellular matrix invasion, decreased solidity and a greater perimeter, reflecting increased invasion compared to non-LAM control smooth muscle cells. Sorafenib significantly inhibited this invasion in both LAM spheroids and LAM-LEC organoids compared to their respective controls. We identified TGFβ1ι1, a molecular adapter coordinating protein-protein interactions at the focal adhesion complex and known to regulate VEGF, TGFβ and Wnt signalling, as a Sorafenib-regulated kinase in LAM-cells. In conclusion we have developed a novel 3D co-culture LAM model and have demonstrated the effectiveness of Sorafenib to inhibit LAM-cell invasion, identifying new avenues for therapeutic intervention.

The lymphatic vasculature in lung function and respiratory disease

The lymphatic vasculature maintains tissue homeostasis via fluid drainage in the form of lymph and immune surveillance due to migration of leukocytes through the lymphatics to the draining lymph nodes. Lymphatic endothelial cells (LECs) form the lymphatic vessels and lymph node sinuses and are key players in shaping immune responses and tolerance. In the healthy lung, the vast majority of lymphatic vessels are found along the bronchovascular structures, in the interlobular septa, and in the subpleural space. Previous studies in both mice and humans have shown that the lymphatics are necessary for lung function from the neonatal period through adulthood. Furthermore, changes in the lymphatic vasculature are observed in nearly all respiratory diseases in which they have been analyzed. Recent work has pointed to a causative role for lymphatic dysfunction in the initiation and progression of lung disease, indicating that these vessels may be active players in pathologic processes in the lung. However, the mechanisms by which defects in lung lymphatic function are pathogenic are understudied, leaving many unanswered questions. A more comprehensive understanding of the mechanistic role of morphological, functional, and molecular changes in the lung lymphatic endothelium in respiratory diseases is a promising area of research that is likely to lead to novel therapeutic targets. In this review, we will discuss our current knowledge of the structure and function of the lung lymphatics and the role of these vessels in lung homeostasis and respiratory disease.

Tumor-promoting roles of HMMR in lung adenocarcinoma

Searching for differential genes in lung adenocarcinoma (LUAD) is vital for research. Hyaluronan mediated motility receptor (HMMR) promotes malignant progression of cancer patients. However, the molecular regulators of HMMR-mediated LUAD onset are unknown. This work aimed to study the relevance of HMMR to proliferation, migration and invasion of LUAD cells. Let-7c-5p and HMMR levels in LUAD cells and HLF-a cells were assessed, and their correlation was also detected. Their interaction was determined by dual-luciferase experiments and qRT-PCR. Cell proliferation, migration and invasion potentials in vitro were validated through cell counting kit-8 (CCK-8), colony formation, scratch healing, and transwell assays. The expression of HMMR was examined by qRT-PCR and western blot and the expression of let-7c-5p was assayed by qRT-PCR. It was found that HMMR level was increased in LUAD and negatively correlated with let-7c-5p level. Let-7c-5p directly targeted HMMR to repress LUAD cell proliferation, migration and invasion. The above data illustrated that the let-7c-5p/HMMR axis may provide certain therapeutic value for LUAD patients.

Phenotypic Features of Cystic Lung Disease in Proteus Syndrome: A Clinical Trial

Rationale: Limited information is available regarding cystic lung disease in Proteus syndrome, a rare overgrowth disorder caused by a somatic activating variant in AKT1. Objectives: To define the phenotype of cystic lung disease in Proteus syndrome. Methods: Medical records, pulmonary function tests, and chest computed tomography of 39 individuals with Proteus syndrome evaluated at a single center were retrospectively reviewed. Lung histopathology from five affected individuals was examined. Results: Cystic lung disease affected 26 (67%) of 39 individuals. The mean age of affected individuals was 17.1 years. The lung cysts varied in size and location. Focal regions of heterogeneous lung parenchyma resembling emphysema were found in 81% of affected individuals. Mass effect was seen in 12% of affected individuals; pneumothorax occurred in one. Dyspnea and respiratory infections were reported by 38% and 35% of affected individuals, respectively. Abnormal pulmonary function and scoliosis were found in 96% of affected individuals. Lung disease progressed in seven of 10 affected individuals, and all five affected individuals younger than 20 years of age had progressive cystic lung disease. Three affected individuals had symptomatic improvement after lung resection. Histopathology showed cystic air space enlargement of varying severity. Conclusions: Cystic lung disease is common in Proteus syndrome and is likely to progress in affected individuals younger than 20 years of age. Screening asymptomatic individuals with Proteus syndrome for cystic lung disease is indicated. Surgical lung resection is a therapeutic option for affected individuals with severe disease. Clinical trial registered with www.clinicaltrials.gov (NCT00001403).

Bioinformatics analysis of inflammation and oncology in pulmonary lymphangioleiomyomatosis

This study investigates the molecular markers and biological pathways of pulmonary lymphangioleiomyomatosis. We analyzed 2 gene expression profiles in the gene expression omnibus Gene Expression Omnibus database for normal lung tissue and lymphangioleiomyomatosis and identified differential expressed genes in pulmonary lymphangioleiomyomatosis. Ninety-one differentially expressed genes were identified, including 36 upregulated genes and 55 downregulated genes. Hub genes and pathogenic pathways associated with disease development were subsequently identified by enrichment analysis and protein-protein interaction network. Analysis showed that differential expressed genes are mainly involved in the biological behavior of tumor cell proliferation and invasion as well as the inflammatory response. We have identified 10 hub genes in the protein-protein interaction network. Hub genes play an important role in the proliferation and inflammatory response involved in tumor cell proliferation. This study deepens the understanding of lymphangioleiomyomatosis disease and provides a biological basis for further clinical diagnosis and treatment.

Pulmonary lymphangioleiomyomatosis (LAM): A literature overview and case report

Lymphangioleiomyomatosis is a rare multisystem disease associated with genetic mutations. The disease usually occurs in women of childbearing age and is characterized by infiltration of immature smooth muscle cells into the lungs, airways, and axial lymphatic systems of the chest and abdomen. The disease often destroys lung parenchyma and produces air cysts. Lymphangioleiomyomatosis cell infiltration of the lymphatic axis can affect hilar lymph nodes, mediastinal ganglia, and extrathoracic lymph nodes. The disease can cause lymphatic dilation in the lungs and thoracic ducts, causing chylous effusion into the pleural or abdominal cavities. Invasion of cells into the walls of pulmonary veins can lead to venous obstruction and pulmonary venous hypertension with hemoptysis. Most patients present with cough, dyspnea, pneumothorax, hemoptysis, and abnormal lung function. Definitive diagnosis is usually based on histopathology and immunohistochemistry. We present a case of LAM in a 36-year-old female patient who was confirmed by specimens obtained from pneumothorax surgery and positive immunohistochemical staining with HMB-45.

Diagnostic performance of VEGF-D for lymphangioleiomyomatosis: a meta-analysis

Objective:

VEGF-D is a potential biomarker for lymphangioleiomyomatosis (LAM); however, its diagnostic performance has yet to be systematically studied.

Methods:

We searched PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library to identify primary studies on VEGF-D in relation to the diagnosis of LAM. The quality of the studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Summary estimates of diagnostic accuracy were pooled using a bivariate random effects model. Subgroup and sensitivity analyses were performed to explore possible heterogeneity. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was applied to rate the quality of evidence and indicate the strength of recommendations.

Results:

Ten studies involving 945 patients were of high risk in quality, as assessed using the QUADAS-2. The pooled diagnostic parameters were indicated as follows: sensitivity = 0.82 (95% CI, 0.71-0.90); specificity = 0.98 (95% CI, 0.94-0.99); and diagnostic OR = 197 (95% CI, 66-587). The AUC of summary ROC analysis was 0.98. The subgroup and sensitivity analyses revealed that the overall performance was not substantially affected by the composition of the control group, prespecified cutoff value, the country of origin, or different cutoff values (p > 0.05 for all). A strong recommendation for serum VEGF-D determination to aid in the diagnosis of LAM was made according to the GRADE.

Conclusions:

VEGF-D seems to have great potential implications for the diagnosis of LAM in clinical practice due to its excellent specificity and suboptimal sensitivity.

Sirolimus Suppresses Phosphorylation of Cofilin and Reduces Interstitial Septal Thickness in Sporadic Lymphangioleiomyomatosis

Sporadic lymphangioleiomyomatosis (S-LAM) is a rare lung disease characterized by the proliferation of smooth muscle-like LAM cells and progressive cystic destruction. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has a proven efficacy in patients with LAM. However, the therapeutic mechanisms of sirolimus in LAM remain unclear. We aimed to evaluate sirolimus-related lung parenchymal changes and the potential effect in LAM cells and modulating pathological cystic destruction. Lung specimens were examined for histopathological changes by HMB45 staining and compared the LAM patients treated with and without sirolimus. We detected the overexpression of mTOR, HMB45, and phosphorylation of cofilin (p-cofilin) in LAM patients. Sirolimus showed efficacy in patients with LAM, who exhibited a reduced expression of mTOR and p-cofilin as well as reduced interstitial septal thickness. In addition, sirolimus suppresses mTOR and p-cofilin, thus suppressing the migration and proliferation of LAM cells isolated from the patient's lung tissue. This study demonstrates that interstitial septal thickness, as determined by histological structural analysis. Sirolimus effectively reduced the expression of p-cofilin and interstitial septal thickness, which may be a novel mechanism by sirolimus. Moreover, we develop a new method to isolate and culture the LAM cell, which can test the possibility of medication in vitro and impact this current study has on the LAM field. The development of approaches to interfere with mTOR-cofilin1-actin signaling may result in an option for S-LAM therapy.

Regulation of PTEN translation by PI3K signaling maintains pathway homeostasis

The PI3K pathway regulates cell metabolism, proliferation, and migration, and its dysregulation is common in cancer. We now show that both physiologic and oncogenic activation of PI3K signaling increase the expression of its negative regulator PTEN. This limits the duration of the signal and output of the pathway. Physiologic and pharmacologic inhibition of the pathway reduces PTEN and contributes to the rebound in pathway activity in tumors treated with PI3K inhibitors and limits their efficacy. Regulation of PTEN is due to mTOR/4E-BP1-dependent control of its translation and is lost when 4E-BP1 is deleted. Translational regulation of PTEN is therefore a major homeostatic regulator of physiologic PI3K signaling and plays a role in reducing the pathway activation by oncogenic PIK3CA mutants and the antitumor activity of PI3K pathway inhibitors. However, pathway output is hyperactivated in tumor cells with coexistent PI3K mutation and loss of PTEN function.

Circulating Lymphangioleiomyomatosis Tumor Cells With Loss of Heterozygosity in the TSC2 Gene Show Increased Aldehyde Dehydrogenase Activity

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a destructive metastasizing neoplasm of the lung characterized by proliferation of LAM cells in specialized lung nodules. LAM cells are characterized by expression of the prometastatic and cancer-initiating hyaluronan receptor CD44v6, and loss of heterozygosity (LOH) of TSC1 and TSC2. The circulating neoplastic LAM cells are thought to be involved in metastasis. Because LAM cells display properties of neoplastic, metastatic, and stem cell-like cancer cells, we hypothesized that elevated aldehyde dehydrogenase (ALDH) activity, characteristic of cancer and stem cells, is a property of LAM cells.

METHODS

We performed an in silico search of ALDH genes in microdissected LAM lung nodules. To identify circulating LAM cells, we osmotically removed red blood cells from whole blood to obtain peripheral blood mononuclear cells, which were then sorted by fluorescence-activated cell sorting based on their level of ALDH activity.

RESULTS

Microdissected LAM lung nodules possess a distinctive ALDH gene profile. The cell subpopulation with high ALDH activity, isolated from circulating cells, possessed TSC2 LOH in 8 of 14 patients with LAM. Approximately 60% of the circulating cells with high ALDH activity expressed CD44v6. Cells with TSC2 LOH from patients with LAM and LAM/TSC exhibited different properties in different body locations, but all cell types showed high ALDH activity.

CONCLUSIONS

This new procedure allows for isolation of circulating LAM cells from cultured cells, blood, and chylous effusions and shows that circulating LAM cells are heterogeneous with neoplastic, metastatic, and cancer-stem cell-like properties.

In situ analysis of mTORC1/2 and cellular metabolism-related proteins in human Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare progressive cystic lung disease with features of a low-grade neoplasm. It is primarily caused by mutations in TSC1 or TSC2 genes. Sirolimus, an inhibitor of mTOR complex 1 (mTORC1), slows down disease progression in some, but not all patients. Hitherto, other potential therapeutic targets such as mTOR complex 2 (mTORC2) and various metabolic pathways have not been investigated in human LAM tissues. The aim of this study was to assess activities of mTORC1, mTORC2 and various metabolic pathways in human LAM tissues through analysis of protein expression. Immunohistochemical analysis of p-S6 (mTORC1 downstream protein), Rictor (mTORC2 scaffold protein) as well as GLUT1, GAPDH, ATPB, GLS, MCT1, ACSS2 and CPT1A (metabolic pathway markers) were performed on lung tissue from 11 patients with sporadic LAM. Immunoreactivity was assessed in LAM cells with bronchial smooth muscle cells as controls. Expression of p-S6, Rictor, GAPDH, GLS, MCT1, ACSS2 and CPT1A was significantly higher in LAM cells than in bronchial smooth muscle cells (P<.01). No significant differences were found between LAM cells and normal bronchial smooth muscle cells in GLUT1 and ATPB expression. The results are uniquely derived from human tissue and indicate that, in addition to mTORC1, mTORC2 may also play an important role in the pathobiology of LAM. Furthermore, glutaminolysis, acetate utilization and fatty acid β-oxidation appear to be the preferred bioenergetic pathways in LAM cells. mTORC2 and these preferred bioenergetic pathways appear worthy of further study as they may represent possible therapeutic targets in the treatment of LAM.