Recent insights into the role of L1CAM in cancer initiation and progression

Prospects and challenges in using neuronal extracellular vesicles in biomarker research

Extracellular vesicles (EVs) hold promise as a source of disease biomarkers. The diverse molecular cargo of EVs can potentially indicate the status of their tissue of origin, even against the complex background of whole plasma. The main tools currently available for assessing biomarkers of brain health include brain imaging and analysis of the cerebrospinal fluid of patients. Given the costs and difficulties associated with these methods, isolation of EVs of neuronal origin (NEVs) from the blood is an attractive approach to identify brain-specific biomarkers. This perspective describes current key challenges in EV- and NEV-based biomarker research. These include the relative low abundance of EVs, the lack of validated isolation methods, and the difficult search for an adequate target for immunocapturing NEVs. We discuss that these challenges must be addressed before NEVs can fulfill their potential for biomarker research. HIGHLIGHTS: NEVs are promising sources of biomarkers for brain disorders. Immunocapturing NEVs from complex biofluids presents several challenges. The choice of surface target for capture will determine NEV yield. Contamination by non-EV sources is relevant for biomarkers at low concentrations.

Functional study of a rare L1CAM gene c.1759G>C variant prove its pathogenicity

L1 syndrome, a neurological disorder with an X-linked inheritance pattern, mainly results from mutations occurring in the L1 cell adhesion molecule (L1CAM) gene. The L1CAM molecule, belonging to the immunoglobulin (Ig) superfamily of neurocyte adhesion molecules, plays a pivotal role in facilitating intercellular signal transmission across membranes and is indispensable for proper neuronal development and function. This study identified a rare missense variant (c.1759G>C; p.G587R) in the L1CAM gene within a male fetus presenting with hydrocephalus. Due to a lack of functional analysis, the significance of the L1CAM mutation c.1759G>C (p.G587R) remains unknown. We aimed to perform further verification for its pathogenicity. Blood samples were obtained from the proband and his parents for trio clinical exome sequencing and mutation analysis. Expression level analysis was conducted using western blot techniques. Immunofluorescence was employed to investigate L1CAM subcellular localization, while cell aggregation and cell scratch assays were utilized to assess protein function. The study showed that the mutation (c.1759G>C; p.G587R) affected posttranslational glycosylation modification and induced alterations in the subcellular localization of L1-G587R in the cells. It resulted in the diminished expression of L1CAM on the cell surface and accumulation in the endoplasmic reticulum. The p.G587R altered the function of L1CAM protein and reduced homophilic adhesion capacity of proteins, leading to impaired adhesion and migration of proteins between cells. Our findings provide first biological evidence for the association between the missense mutation (c.1759G>c; p.G587R) in the L1CAM gene and L1 syndrome, confirming the pathogenicity of this missense mutation.

Emergence of Extracellular Vesicles as "Liquid Biopsy" for Neurological Disorders: Boom or Bust

Extracellular vesicles (EVs) have emerged as an attractive liquid biopsy approach in the diagnosis and prognosis of multiple diseases and disorders. The feasibility of enriching specific subpopulations of EVs from biofluids based on their unique surface markers has opened novel opportunities to gain molecular insight from various tissues and organs, including the brain. Over the past decade, EVs in bodily fluids have been extensively studied for biomarkers associated with various neurological disorders, such as Alzheimer's disease, Parkinson's disease, schizophrenia, bipolar disorder, major depressive disorders, substance use disorders, human immunodeficiency virus-associated neurocognitive disorder, and cancer/treatment-induced neurodegeneration. These studies have focused on the isolation and cargo characterization of either total EVs or brain cells, such as neuron-, astrocyte-, microglia-, oligodendrocyte-, pericyte-, and endothelial-derived EVs from biofluids to achieve early diagnosis and molecular characterization and to predict the treatment and intervention outcomes. The findings of these studies have demonstrated that EVs could serve as a repetitive and less invasive source of valuable molecular information for these neurological disorders, supplementing existing costly neuroimaging techniques and relatively invasive measures, like lumbar puncture. However, the initial excitement surrounding blood-based biomarkers for brain-related diseases has been tempered by challenges, such as lack of central nervous system specificity in EV markers, lengthy protocols, and the absence of standardized procedures for biological sample collection, EV isolation, and characterization. Nevertheless, with rapid advancements in the EV field, supported by improved isolation methods and sensitive assays for cargo characterization, brain cell-derived EVs continue to offer unparallel opportunities with significant translational implications for various neurological disorders. SIGNIFICANCE STATEMENT: Extracellular vesicles present a less invasive liquid biopsy approach in the diagnosis and prognosis of various neurological disorders. Characterizing these vesicles in biofluids holds the potential to yield valuable molecular information, thereby significantly impacting the development of novel biomarkers for various neurological disorders. This paper has reviewed the methodology employed to isolate extracellular vesicles derived from various brain cells in biofluids, their utility in enhancing the molecular understanding of neurodegeneration, and the potential challenges in this research field.

Cellular origin and molecular mechanisms of lung metastases in patients with aggressive hepatoblastoma

BACKGROUND AND AIMS

Lung metastases are the most threatening signs for patients with aggressive hepatoblastoma (HBL). Despite intensive studies, the cellular origin and molecular mechanisms of lung metastases in patients with aggressive HBL are not known. The aims of these studies were to identify metastasis-initiating cells in primary liver tumors and to determine if these cells are secreted in the blood, reach the lung, and form lung metastases.

APPROACH

We have examined mechanisms of activation of key oncogenes in primary liver tumors and lung metastases and the role of these mechanisms in the appearance of metastasis-initiating cells in patients with aggressive HBL by RNA-Seq, immunostaining, chromatin immunoprecipitation, Real-Time Quantitative Reverse Transcription PCR and western blot approaches. Using a protocol that mimics the exit of metastasis-initiating cells from tumors, we generated 16 cell lines from liver tumors and 2 lines from lung metastases of patients with HBL.

RESULTS

We found that primary HBL liver tumors have a dramatic elevation of neuron-like cells and cancer-associated fibroblasts and that these cells are released into the bloodstream of patients with HBL and found in lung metastases. In the primary liver tumors, the ph-S675-β-catenin pathway activates the expression of markers of cancer-associated fibroblasts; while the ZBTB3-SRCAP pathway activates the expression of markers of neurons via cancer-enhancing genomic regions/aggressive liver cancer domains leading to a dramatic increase of cancer-associated fibroblasts and neuron-like cells. Studies of generated metastasis-initiating cells showed that these cells proliferate rapidly, engage in intense cell-cell interactions, and form tumor clusters. The inhibition of β-catenin in HBL/lung metastases-released cells suppresses the formation of tumor clusters.

CONCLUSIONS

The inhibition of the β-catenin-cancer-enhancing genomic regions/aggressive liver cancer domains axis could be considered as a therapeutic approach to treat/prevent lung metastases in patients with HBL.

Noninvasive urinary protein signatures combined clinical information associated with microvascular invasion risk in HCC patients

BACKGROUND

Microvascular invasion (MVI) is the main factor affecting the prognosis of patients with hepatocellular carcinoma (HCC). The aim of this study was to identify accurate diagnostic biomarkers from urinary protein signatures for preoperative prediction.

METHODS

We conducted label-free quantitative proteomic studies on urine samples of 91 HCC patients and 22 healthy controls. We identified candidate biomarkers capable of predicting MVI status and combined them with patient clinical information to perform a preoperative nomogram for predicting MVI status in the training cohort. Then, the nomogram was validated in the testing cohort (n = 23). Expression levels of biomarkers were further confirmed by enzyme-linked immunosorbent assay (ELISA) in an independent validation HCC cohort (n = 57).

RESULTS

Urinary proteomic features of healthy controls are mainly characterized by active metabolic processes. Cell adhesion and cell proliferation-related pathways were highly defined in the HCC group, such as extracellular matrix organization, cell-cell adhesion, and cell-cell junction organization, which confirms the malignant phenotype of HCC patients. Based on the expression levels of four proteins: CETP, HGFL, L1CAM, and LAIR2, combined with tumor diameter, serum AFP, and GGT concentrations to establish a preoperative MVI status prediction model for HCC patients. The nomogram achieved good concordance indexes of 0.809 and 0.783 in predicting MVI in the training and testing cohorts.

CONCLUSIONS

The four-protein-related nomogram in urine samples is a promising preoperative prediction model for the MVI status of HCC patients. Using the model, the risk for an individual patient to harbor MVI can be determined.

Reactivation of embryonic genetic programs in tissue regeneration and disease

Embryonic genetic programs are reactivated in response to various types of tissue damage, providing cell plasticity for tissue regeneration or disease progression. In acute conditions, these programs remedy the damage and then halt to allow a return to homeostasis. In chronic situations, including inflammatory diseases, fibrosis and cancer, prolonged activation of embryonic programs leads to disease progression and tissue deterioration. Induction of progenitor identity and cell plasticity, for example, epithelial-mesenchymal plasticity, are critical outcomes of reactivated embryonic programs. In this Review, we describe molecular players governing reactivated embryonic genetic programs, their role during disease progression, their similarities and differences and lineage reversion in pathology and discuss associated therapeutics and drug-resistance mechanisms across many organs. We also discuss the diversity of reactivated programs in different disease contexts. A comprehensive overview of commonalities between development and disease will provide better understanding of the biology and therapeutic strategies.

Regulation of glucose and glutamine metabolism to overcome cisplatin resistance in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a bile duct cancer and a rare malignant tumor with a poor prognosis owing to the lack of an early diagnosis and resistance to conventional chemotherapy. A combination of gemcitabine and cisplatin is the typically attempted first-line treatment approach. However, the underlying mechanism of resistance to chemotherapy is poorly understood. We addressed this by studying dynamics in the human ICC SCK cell line. Here, we report that the regulation of glucose and glutamine metabolism was a key factor in overcoming cisplatin resistance in SCK cells. RNA sequencing analysis revealed a high enrichment cell cycle-related gene set score in cisplatin-resistant SCK (SCK-R) cells compared to parental SCK (SCK WT) cells. Cell cycle progression correlates with increased nutrient requirement and cancer proliferation or metastasis. Commonly, cancer cells are dependent upon glucose and glutamine availability for survival and proliferation. Indeed, we observed the increased expression of GLUT (glucose transporter), ASCT2 (glutamine transporter), and cancer progression markers in SCK-R cells. Thus, we inhibited enhanced metabolic reprogramming in SCK-R cells through nutrient starvation. SCK-R cells were sensitized to cisplatin, especially under glucose starvation. Glutaminase-1 (GLS1), which is a mitochondrial enzyme involved in tumorigenesis and progression in cancer cells, was upregulated in SCK-R cells. Targeting GLS1 with the GLS1 inhibitor CB-839 (telaglenastat) effectively reduced the expression of cancer progression markers. Taken together, our study results suggest that a combination of GLUT inhibition, which mimics glucose starvation, and GLS1 inhibition could be a therapeutic strategy to increase the chemosensitivity of ICC. [BMB Reports 2023; 56(11): 600-605].

L1CAM deployed perivascular tumor niche promotes vessel wall invasion of tumor thrombus and metastasis of renal cell carcinoma

The survival of tumor cells in the bloodstream, and vasculature adhesion at metastatic sites are crucial for tumor metastasis. Perivascular invasion aids tumor cell self-renewal, survival, and formation of metastases by facilitating readily available oxygen, nutrients, and endothelial-derived paracrine factors. Renal cell carcinoma (RCC) is among the most prevalent tumors of the urinary system, and the formation of venous tumor thrombus (VTT) is a characteristic feature of RCC. We observed high expression of L1CAM in the VTT with vessel wall invasion. L1CAM promotes the adhesion, migration, and invasion ability of RCC and enhances metastasis by interacting with ITGA5, which elicits activation of signaling downstream of integrin α5β1. L1CAM promotes ADAM17 transcription to facilitate transmembrane ectodomain cleavage and release of soluble L1CAM. In response to soluble L1CAM, vascular endothelial cells release several cytokines and chemokines. Endothelial-derived CXCL5 and its receptor CXCR2 promote the migration and intravasation of RCC toward endothelial cells suggesting that crosstalk between endothelial cells and tumor cells has a direct guiding role in driving the metastatic spread of RCC. LICAM plays a crucial role in the invasive ability of RCC, and regulation of L1CAM expression may contribute therapeutically to preventing RCC progression.

Viral delivery of L1CAM promotes axonal extensions by embryonic cerebral grafts in mouse brain

Cell replacement therapy is expected as a new and more radical treatment against brain damage. We previously reported that transplanted human cerebral organoids extend their axons along the corticospinal tract in rodent brains. The axons reached the spinal cord but were still sparse. Therefore, this study optimized the host brain environment by the adeno-associated virus (AAV)-mediated expression of axon guidance proteins in mouse brain. Among netrin-1, SEMA3, and L1CAM, only L1CAM significantly promoted the axonal extension of mouse embryonic brain tissue-derived grafts. L1CAM was also expressed by donor neurons, and this promotion was exerted in a haptotactic manner by their homophilic binding. Primary cortical neurons cocultured on L1CAM-expressing HEK-293 cells supported this mechanism. These results suggest that optimizing the host environment by the AAV-mediated expression of axon guidance molecules enhances the effect of cell replacement therapy.

Microfluidic-Assisted Production of Gastro-Resistant Active-Targeted Diatomite Nanoparticles for the Local Release of Galunisertib in Metastatic Colorectal Cancer Cells

The oral route is highly desirable for colorectal cancer (CRC) treatment because it allows concentrating the drug in the colon and achieving a localized effect. However, orally administered drugs are often metabolized in the liver, resulting in reduced efficacy and the need for higher doses. Nanoparticle-based drug delivery systems can be engineered to prevent the diffusion of the drug in the stomach, addressing the release at the target site, and enhancing the efficacy of the delivered drug. Here, an orally administrable galunisertib delivery system is developed with gelatin-covered diatomite nanoparticles targeting the ligand 1-cell adhesion molecule (L1-CAM) on metastatic cells, and further encapsulated in an enteric matrix by microfluidics. The gastro-resistant polymer protects the nanoparticles from the action of the digestive enzymes and allows for a sustained release of galunisertib at the intestinal pH. The efficacy of antibody-antigen interactions to drive the internalization of nanoparticles in the targeted cells is investigated in CRC cells expressing abnormal (SW620) or basal levels (Caco-2, HT29-MTX) of L1-CAM. The combination of local drug release and active targeting enhances the effect of the delivered galunisertib, which inhibits the migration of the SW620 cells with greater efficiency compared to the free drug.

Molecular testing for endometrial cancer: An SGO clinical practice statement

The Cancer Genome Atlas publication first described the genomic landscape of endometrial cancer and characterized these cancers into four molecular subtypes with different prognoses. The Proactive Molecular Classifier for Endometrial Cancer was developed to more easily and inexpensively classify endometrial cancers into four similar molecular subtypes which are termed POLE, mismatch repair deficient, p53 abnormal and no specific molecular profile. Beyond these four subtypes, other molecular biomarkers may influence clinical behavior and response to targeted therapies and include beta-catenin, Her2 amplification, PI3K/mTOR/AKT alterations, L1CAM, hormone receptor expression, tumor mutational burden, and ARID1A. There are numerous clinical trials exploring treatment escalation and de-escalation within the four molecular subtypes as well as matching targeted therapies to specific mutational or biomarker profiles. All endometrial cancers should undergo basic molecular classification that includes assessment of mismatch repair status. POLE and p53 status are prognostic and may become actionable in the future. Clinicians who treat patients with endometrial cancer should understand the role of molecular classification in guiding treatment. The goal of this practice statement is to guide appropriate testing, interpretation, and application of molecular information in endometrial cancer.

Tryptophan hydroxylase 1 drives glioma progression by modulating the serotonin/L1CAM/NF-κB signaling pathway

Background

Glioma is one of the main causes of cancer-related mortality worldwide and is associated with high heterogeneity. However, the key players determining the fate of glioma remain obscure. In the present study, we shed light on tumor metabolism and aimed to investigate the role of tryptophan hydroxylase 1 (TPH-1) in the advancement of glioma.

Method

Herein, the levels of TPH-1 expression in glioma tissues were evaluated using The Cancer Genome Atlas (TCGA) database. Further, the proliferative characteristics and migration ability of TPH-1 overexpressing LN229/T98G cells were evaluated. Additionally, we performed a cytotoxicity analysis using temozolomide (TMZ) in these cells. We also examined the tumor growth and survival time in a mouse model of glioma treated with chemotherapeutic agents and a TPH-1 inhibitor.

Results

The results of both clinical and experimental data showed that excess TPH-1 expression resulted in sustained glioma progression and a dismal overall survival in these patients. Mechanistically, TPH-1 increased the production of serotonin in glioma cells. The elevated serotonin levels then augmented the NF-κB signaling pathway through the upregulation of the L1-cell adhesion molecule (L1CAM), thereby contributing to cellular proliferation, invasive migration, and drug resistance. In vivo experiments demonstrated potent antitumor effects, which benefited further from the synergistic combination of TMZ and LX-1031.

Conclusion

Taken together, these data suggested that TPH-1 facilitated cellular proliferation, migration, and chemoresistance in glioma through the serotonin/L1CAM/NF-κB pathway. By demonstrating the link of amino acid metabolic enzymes with tumor development, our findings may provide a potentially viable target for therapeutic manipulation aimed at eradicating glioma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09569-2.

L1CAM-associated extracellular vesicles: A systematic review of nomenclature, sources, separation, and characterization

When released into biological fluids like blood or saliva, brain extracellular vesicles (EVs) might provide a window into otherwise inaccessible tissue, contributing useful biomarkers of neurodegenerative and other central nervous system (CNS) diseases. To enrich for brain EVs in the periphery, however, cell-specific EV surface markers are needed. The protein that has been used most frequently to obtain EVs of putative neuronal origin is the transmembrane L1 cell adhesion molecule (L1CAM/CD171). In this systematic review, we examine the existing literature on L1CAM and EVs, including investigations of both neurodegenerative disease and cancer through the lens of the minimal information for studies of EVs (MISEV), specifically in the domains of nomenclature usage, EV sources, and EV separation and characterization. Although numerous studies have reported L1CAM-associated biomarker signatures that correlate with disease, interpretation of these results is complicated since L1CAM expression is not restricted to neurons and is also upregulated during cancer progression. A recent study has suggested that L1CAM epitopes are present in biofluids mostly or entirely as cleaved, soluble protein. Our findings on practices and trends in L1CAM-mediated EV separation, enrichment, and characterization yield insights that may assist with interpreting results, evaluating rigor, and suggesting avenues for further exploration.

POU2F3 beyond thymic carcinomas: expression across the spectrum of thymomas hints to medullary differentiation in type A thymoma

The thymic medulla comprises various cell types, including tuft cells that are involved in innate immunity. We recently reported that in Western cohorts of patients, most thymic squamous cell carcinomas (TSQCCs), in contrast to thymomas, exhibit strong and extensive expression of tuft cell markers, including the tuft cell master regulator, POU2F3. On closer inspection of 94 thymomas that cover the full spectrum of thymoma histotypes, we now find by immunohistochemistry that approximately half of types A, AB, and B1 thymomas contain small numbers (< 10%) of cells expressing POU2F3, while most types B2 and B3 thymomas do not (p < 0.05). Further, in rarer types A and AB thymomas with adenoid growth pattern, POU2F3( +) cells formed aggregates and co-expressed KIT, as did the tumor cells in 100% (9/9) of TSQCCs expressing POU2F3. However, the expression of another tuft cell marker, L1CAM, still distinguished TSQCC from the spectrum of thymomas that were all L1CAM-negative. This study is the first to demonstrate the high frequency of POU2F3 expression in an Asian cohort of TSQCCs. The common occurrence of scattered POU2F3( +) cells in types A and AB thymomas hints at their variable degree of medullary differentiation and supports the historical hypothesis of the medullary nature of type A thymomas. Immunohistochemistry of L1CAM may be a valuable tool to differentiate TSQCCs from thymomas.

From Proteomic Mapping to Invasion-Metastasis-Cascade Systemic Biomarkering and Targeted Drugging of Mutant BRAF-Dependent Human Cutaneous Melanomagenesis

Simple Summary

Despite the recent advances in human malignancy therapy, metastasis and chemoresistance remain the principal causes of cancer-derived deaths. Given the fatal forms of cutaneous metastatic melanoma, we herein employed primary (WM115) and metastatic (WM266-4) melanoma cells, both obtained from the same patient, to identify novel biomarkers and therapeutic agents. Through state-of-the-art technologies including deep proteome landscaping, immunofluorescence phenotyping, and drug toxicity screening, we were able to describe new molecular programs, oncogenic drivers, and drug regimens, controlling the invasion-metastasis cascade during BRAF^V600D-dependent melanomagenesis. It proved that proteomic navigation could foster the development of systemic biomarkering and targeted drugging for successful treatment of advanced disease.

Abstract

Melanoma is classified among the most notoriously aggressive human cancers. Despite the recent progress, due to its propensity for metastasis and resistance to therapy, novel biomarkers and oncogenic molecular drivers need to be promptly identified for metastatic melanoma. Hence, by employing nano liquid chromatography-tandem mass spectrometry deep proteomics technology, advanced bioinformatics algorithms, immunofluorescence, western blotting, wound healing protocols, molecular modeling programs, and MTT assays, we comparatively examined the respective proteomic contents of WM115 primary (n = 3955 proteins) and WM266-4 metastatic (n = 6681 proteins) melanoma cells. It proved that WM115 and WM266-4 cells have engaged hybrid epithelial-to-mesenchymal transition/mesenchymal-to-epithelial transition states, with TGF-β controlling their motility in vitro. They are characterized by different signatures of SOX-dependent neural crest-like stemness and distinct architectures of the cytoskeleton network. Multiple signaling pathways have already been activated from the primary melanoma stage, whereas HIF1α, the major hypoxia-inducible factor, can be exclusively observed in metastatic melanoma cells. Invasion-metastasis cascade-specific sub-routines of activated Caspase-3-triggered apoptosis and LC3B-II-dependent constitutive autophagy were also unveiled. Importantly, WM115 and WM266-4 cells exhibited diverse drug response profiles, with epirubicin holding considerable promise as a beneficial drug for metastatic melanoma clinical management. It is the proteome navigation that enables systemic biomarkering and targeted drugging to open new therapeutic windows for advanced disease.

Forkhead-box A3 (FOXA3) represses cancer stemness and partially potentiates chemosensitivity by targeting metastasis-associated in colon cancer 1 (MACC1) signaling pathway in colorectal cancer cells

BACKGROUND

The major challenge to the treatment of advanced colorectal cancer (CRC) is persistent occurrence of chemoresistance. One of the established etiologies is the existence of cancerstem-like cells (CSCs) using which tumors resist to external therapeutic challenges.

OBJECTIVE

The forkhead-box A3 (FOXA3) is a potent transcription factor that potentiates the acquisition and maintenance of stemness fate in many physiological systems. However, its effect on cancer stemness, particularly treatment, has not been explored in CRC, forming the basis of the current study.

METHODS

FOXA3 expression in oxaliplatin-resistant CRC tissues and cells was evaluated using RT-qPCR. Effects of FOXA3 manipulation on sensitivity to oxaliplatin were assessed using WST-1, apoptotic ELISA, colony formation and xenograft model. Effects of FOXA3 alteration on CSCs were determined using tumor sphere assay and CD44 staining. Transcriptional regulation of MACC1 by FOXA3 was studied using ChIP, Co-IP and luciferase reporter assay.

RESULTS

FOXA3 expression was significantly reduced in tumor samples from oxaliplatin-non-responsive patients compared with that in tumor samples from oxaliplatin-sensitive patients. This downregulation of FOXA3 expression predicted a poor post-chemotherapy overall- or disease-free survival in our 117-patient cohort. FOXA3 down-regulation significantly enhanced cell survival and stem-like properties, thus rendering the CRC cells unresponsiveness to oxaliplatin-induced cell death. Mechanistically, the anti-neoplasic effect of FOXA3 was mediated mainly through transcriptional repression of metastasis-associated in colon cancer 1 (MACC1) in oxaliplatin-resistant CRC cells.

CONCLUSION

Our findings establish FOXA3 as a potent tumor suppressor in CRC, which may disrupt the maintenance of stemness and modulate sensitivity to oxaliplatin by inhibiting the transcription of MACC1 within CRC cells.