Trans-homophilic interaction of CADM1 activates PI3K by forming a complex with MAGuK-family proteins MPP3 and Dlg

Comprehensive sequencing of the lung neuroimmune landscape in response to asthmatic induction

Introduction

Evidence demonstrates that sensory neurons respond to pathogenic/allergic infiltration and mediate immune responses, forming an integral part of host defense that becomes hypersensitized during allergy. Our objective was to investigate how asthmatic induction alters the pulmonary neuroimmune transcriptome. We hypothesized that asthmatic induction would upregulate genes in the vagal ganglia (nodose/jugular ganglia), which would be associated with asthmatic immunity, and that these would be clustered, primarily in nodose neurons. Furthermore, lungs would increase transcripts associated with nerve activation, and these would be centered in neural and neuroendocrine-like cells.

Methods

Standard RNA sequencing, single nucleus-RNA sequencing, and spatial RNA sequencing of vagal ganglia. Standard RNA-sequencing and spatial RNA-sequencing of lungs in naïve and mice that have undergone asthmatic induction with Alternaria alternata.

Results

Bulk RNA-seq revealed that genes related to allergen sensing were increased in asthmatic ganglia nodose/jugular ganglia compared to control ganglia. These genes were associated with nodose clusters as shown by single-nucleus RNA sequencing, and a distinct caudal-to-rostral spatial arrangement was presented as delineated by spatial transcriptomics. The distinct clusters closely match previous identification of nodose neuron clusters. Correspondingly, the lung transcriptome was altered with asthmatic induction such that transcripts associated with neural excitation were upregulated. The spatial distribution of these transcripts was revealed by spatial transcriptomics to illustrate that these were expressed in neuroendocrine-like cells/club cells, and neurons.

Conclusions

These results show that the neuroimmune transcriptome is altered in response to asthmatic induction in a cell cluster and spatially distinct manner.

Relief of pain in mice by an antibody with high affinity for cell adhesion molecule 1 on nerves

AIMS

Cell adhesion molecule 1 (CADM1) is a member of the immunoglobulin superfamily and is abundantly expressed on nerve fibers. Recently, the anti-CADM1 ectodomain antibody 3E1 has proven useful as a drug delivery vector for CADM1-expressing cells in vitro. When injected subcutaneously into mice, whether 3E1 accumulates on nerve fibers and serves as an analgesic was examined.

MAIN METHODS

Injected 3E1 was detected by immunohistochemistry and double immunofluorescence. Analgesic effects were verified by a formalin-induced chemical-inflammatory pain test and video-recorded behavior analysis that were performed 6, 12, and 24 h after antibody injection. Primary cultures of mouse dorsal root ganglion (DRG) cells were incubated with 3E1 and expressions of CADM1 and its key downstream molecules were examined by Western blot analyses and live cell imaging. DRG cells were loaded with a Ca2+ fluorescent indicator Fluo-8 and a femtosecond laser pulse was irradiated near the cell body to mechanically stimulate the nerves.

KEY FINDINGS

Subcutaneously injected 3E1 was widely localized almost exclusively on peripheral nerve fibers in the dermis. In formalin tests, 3E1-injected mice exhibited less pain-related behavior than control mice. When 3E1 was added to DRG cell cultures, it localized to neurites and resulted in decreased expression of CADM1, increased phosphorylation of Src and Akt, and CADM1-3E1 complex formation. Femtosecond laser-induced stimulation transmission along neurites was clearly visualized by Fluo-8 fluorescence in control cells, whereas it was markedly suppressed in 3E1-treated cells.

SIGNIFICANCE

3E1 was suggested to be a potential long-acting analgesic based on its high affinity for CADM1.

Multi-dimensional characterization of apoptosis in the tumor microenvironment and therapeutic relevance in melanoma

PURPOSE

Melanoma is widely utilized as a prominent model for the development of immunotherapy, thought an inadequate immune response can occur. Moreover, the development of apoptosis-related therapies and combinations with other therapeutic strategies is impeded by the limited understanding of apoptosis's role within diverse tumor immune microenvironments (TMEs).

METHODS

Here, we constructed an apoptosis-related tumor microenvironment signature (ATM) and employ multi-dimensional analysis to understand the roles of apoptosis in tumor microenvironment. We further assessed the clinical applications of ATM in nine independent cohorts, and anticipated the impact of ATM on cellular drug response in cultured cells.

RESULTS

Our ATM model exhibits robust performance in survival prediction in multiple melanoma cohorts. Different ATM groups exhibited distinct molecular signatures and biological processes. The low ATM group exhibited significant enrichment in B cell activation-related pathways. What's more, plasma cells showed the lowest ATM score, highlighting their role as pivotal contributors in the ATM model. Mechanistically, the analysis of the interplay between plasma cells and other immune cells elucidated their crucial role in orchestrating an effective anti-tumor immune response. Significantly, the ATM signature exhibited associations with therapeutic efficacy of immune checkpoint blockade and the drug sensitivity of various agents, including FDA-approved and clinically utilized drugs targeting the VEGF signaling pathway. Finally, ATM was associated with tertiary lymphoid structures (TLS), exhibiting stronger patient stratification ability compared to classical "hot tumors".

CONCLUSION

Our findings indicate that ATM is a prognostic factor and is associated with the immune response and drug sensitivity in melanoma.

Efficient intracellular drug delivery by co-administration of two antibodies against cell adhesion molecule 1

Cell adhesion molecule 1 (CADM1), a single-pass transmembrane protein, is involved in oncogenesis. We previously demonstrated the therapeutic efficacy of anti-CADM1 ectodomain monoclonal antibodies against mesothelioma; however, the underlying mechanism is unclear. In the present study, we explored the molecular behavior of anti-CADM1 antibodies in CADM1-expressing tumor cells. Sequencing analyses revealed that the anti-CADM1 chicken monoclonal antibodies 3E1 and 9D2 are IgY and IgM isotype antibodies, respectively. Co-administration of 3E1 and 9D2 altered the subcellular distribution of CADM1 from the detergent-soluble fraction to the detergent-resistant fraction in tumor cells. Using recombinant chicken-mouse chimeric antibodies that had been isotype-switched from IgG to IgM, we demonstrated that the combination of the variable region of 3E1 and the constant region of IgM was required for CADM1 relocation. Cytochemical studies showed that 3E1 colocalized with late endosomes/lysosomes after co-administration with 9D2, suggesting that the CADM1-antibody complex is internalized from the cell surface to intracellular compartments by lipid-raft mediated endocytosis. Finally, 3E1 was conjugated with the antimitotic agent monomethyl auristatin E (MMAE) via a cathepsin-cleavable linker. Co-administration of 3E1-monomethyl auristatin E and 9D2 suppressed the growth of multiple types of tumor cells, and this anti-tumor activity was confirmed in a syngeneic mouse model of melanoma. 3E1 and 9D2 are promising drug delivery vehicles for CADM1-expressing tumor cells.

A de novo missense mutation in MPP2 confers an increased risk of Vogt-Koyanagi-Harada disease as shown by trio-based whole-exome sequencing

Vogt-Koyanagi-Harada (VKH) disease is a leading cause of blindness in young and middle-aged people. However, the etiology of VKH disease remains unclear. Here, we performed the first trio-based whole-exome sequencing study, which enrolled 25 VKH patients and 50 controls, followed by a study of 2081 VKH patients from a Han Chinese population to uncover detrimental mutations. A total of 15 de novo mutations in VKH patients were identified, with one of the most important being the membrane palmitoylated protein 2 (MPP2) p.K315N (MPP2-N315) mutation. The MPP2-N315 mutation was highly deleterious according to bioinformatic predictions. Additionally, this mutation appears rare, being absent from the 1000 Genome Project and Genome Aggregation Database, and it is highly conserved in 10 species, including humans and mice. Subsequent studies showed that pathological phenotypes and retinal vascular leakage were aggravated in MPP2-N315 mutation knock-in or MPP2-N315 adeno-associated virus-treated mice with experimental autoimmune uveitis (EAU). In vitro, we used clustered regularly interspaced short palindromic repeats (CRISPR‒Cas9) gene editing technology to delete intrinsic MPP2 before overexpressing wild-type MPP2 or MPP2-N315. Levels of cytokines, such as IL-1β, IL-17E, and vascular endothelial growth factor A, were increased, and barrier function was destroyed in the MPP2-N315 mutant ARPE19 cells. Mechanistically, the MPP2-N315 mutation had a stronger ability to directly bind to ANXA2 than MPP2-K315, as shown by LC‒MS/MS and Co-IP, and resulted in activation of the ERK3/IL-17E pathway. Overall, our results demonstrated that the MPP2-K315N mutation may increase susceptibility to VKH disease.

Molecular interaction of metastasis suppressor genes and tumor microenvironment in breast cancer

Breast cancer (BC) is a leading cause of cancer-related deaths in women worldwide where the process of metastasis is a major contributor to the mortality associated with this disease. Metastasis suppressor genes are a group of genes that play a crucial role in preventing or inhibiting the spread of cancer cells. They suppress the metastasis process by inhibiting colonization and by inducing dormancy. These genes function by regulating various cellular processes in the tumor microenvironment (TME), such as cell adhesion, invasion, migration, and angiogenesis. Dysregulation of metastasis suppressor genes can lead to the acquisition of an invasive and metastatic phenotype and lead to poor prognostic outcomes. The components of the TME generally play a necessary in the metastasis progression of tumor cells. This review has identified and elaborated on the role of a few metastatic suppressors associated with the TME that have been shown to inhibit metastasis in BC by different mechanisms, such as blocking certain cell signaling molecules involved in cancer cell migration, invasion, enhancing immune surveillance of cancer cells, and promoting the formation of a protective extracellular matrix (ECM). Understanding the interaction of metastatic suppressor genes and the components of TME has important implications for the development of novel therapeutic strategies to target the metastatic cascade. Targeting these genes or their downstream signaling pathways offers a promising approach to inhibiting the spread of cancer cells and improves patient outcomes.

A systematic review on the molecular and clinical association between Human Papillomavirus and Human Immunodeficiency Virus co-infection in Head, Neck and Oral squamous cell carcinoma

Head and neck cancer, one of the most commonly prevalent malignancies globally is a complex category of tumours that comprises cancers of the oral cavity, pharynx, and larynx. A specific subgroup of such cancers has been found with some unique chromosomal, therapeutic, and epidemiologic traits with the possibility of affecting via co-infection. About 25% of all head and neck cancers in the population are human papillomavirus infection (HPV)-associated, typically developing in the oropharynx, which comprises the tonsils. In the period of efficient combined antiviral treatment, HPV-positive oral cancers are also becoming a significant contributor to illness and fatality for Human Immunodeficiency Virus (HIV)-infected persons. Although the prevalence and historical background of oral HPV transmission are not thoroughly understood, it seems likely that oral HPV transmission is relatively frequent in HIV-infected people when compared to the overall population. Therefore, there is a need to understand the mechanisms leading to this co-infection, as there is very little research related to that. Hence, this study mainly focus on the therapeutical and biomedical analysis of HPV and HIV co-infection in the above-mentioned cancer, including oral squamous cell carcinoma.

Targeting PI3K by Natural Products: A Potential Therapeutic Strategy for Attention-deficit Hyperactivity Disorder

Attention-Deficit Hyperactivity Disorder (ADHD) is a highly prevalent childhood psychiatric disorder. In general, a child with ADHD has significant attention problems with difficulty concentrating on a subject and is generally associated with impulsivity and excessive activity. The etiology of ADHD in most patients is unknown, although it is considered to be a multifactorial disease caused by a combination of genetics and environmental factors. Diverse factors, such as the existence of mental, nutritional, or general health problems during childhood, as well as smoking and alcohol drinking during pregnancy, are related to an increased risk of ADHD. Behavioral and psychological characteristics of ADHD include anxiety, mood disorders, behavioral disorders, language disorders, and learning disabilities. These symptoms affect individuals, families, and communities, negatively altering educational and social results, strained parent-child relationships, and increased use of health services. ADHD may be associated with deficits in inhibitory frontostriatal noradrenergic neurons on lower striatal structures that are predominantly driven by dopaminergic neurons. Phosphoinositide 3-kinases (PI3Ks) are a conserved family of lipid kinases that control a number of cellular processes, including cell proliferation, differentiation, migration, insulin metabolism, and apoptosis. Since PI3K plays an important role in controlling the noradrenergic neuron, it opens up new insights into research on ADHD and other developmental brain diseases. This review presents evidence for the potential usefulness of PI3K and its modulators as a potential treatment for ADHD.

CADM1 promotes adhesion to vascular endothelial cells and transendothelial migration in cultured GIST cells

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the human gastrointestinal tract. Small intestinal GISTs appear to be associated with poorer prognosis and higher metastasis rate than gastric GISTs of the same size and mitotic index. Recently, we reported that cell adhesion molecule 1 (CADM1) is expressed specifically in most small intestinal GISTs, but not in most gastric GISTs, suggesting that this difference in CADM1 expression between gastric GISTs and small intestinal GISTs might influence the difference in clinical behavior between them. The aim of the present study was to examine whether high CADM1 expression affected proliferation, migration, invasion, adhesion to endothelial cells and transendothelial migration of cultured GIST cells by comparing original GIST-T1 cells with very low CADM1 expression with GIST-T1 cells with high CADM1 expression induced by CADM1 cDNA transfection (GIST-T1-CAD cells). GIST-T1-CAD cells had reduced ability to proliferate, migrate and invade compared with the original GIST-T1 cells, but showed significantly higher ability to adhere to human umbilical vein endothelial cells and migrate through endothelial cell monolayers. Thus, CADM1 may contribute to higher metastasis rates in small intestinal GISTs facilitating tumor cell adhesion to vascular endothelial cell and transendothelial migration of tumor cells. CADM1 might serve as a potential target for inhibition of metastasis in small intestinal GISTs.

Analysis of the key ligand receptor CADM1_CADM1 in the regulation of thyroid cancer based on scRNA-seq and bulk RNA-seq data

INTRODUCTION

Advanced papillary thyroid cancer (PTC) has a poor prognosis, 60~70% of which become radio iodine refractory (RAI-R), but the molecular markers that assess PTC progress to advanced PTC remain unclear. Meanwhile, current targeted therapies are badly effective due to drug resistance and adverse side effects. Ligand-receptor pairs (L/R pairs) play an important role in the interactions between tumor cells and other cells in the tumor microenvironment (TME). Nowadays, therapies targeting ligand-receptor pairs in the TME are advancing rapidly in the treatment of advanced cancers. However, therapies targeting L/R pairs applied to advanced PTC remains challenging because of limited knowledge about L/R pairs in PTC.

METHODS

We screened the critical L/R pair: CADM1-CADM1 using 65311 single-cell RNA sequencing (scRNA-seq) samples from 7 patients in different stage of PTC and bulk RNA-seq datasets containing data from 487 tumor samples and 58 para-carcinoma samples. Moreover, the expression levels of CADM1-CADM1 was assessed by quantitative real time polymerase chain reaction (qRT-PCR) and the function was analyzed using Transwell immigration assay.

RESULTS

We found that CADM1_CADM1 could be regarded as a biomarker representing a good prognosis of PTC. In addition, the high expression of CADM1_CADM1 can strongly increase the sensitivity of many targeted drugs, which can alleviate drug resistance. And the results of qRT-PCR showed us that the expression of CADM1_CADM1 in PTC was down-regulated and overexpression of CADM1 could suppresses tumor cell invasion migration.

CONCLUSION

Our study identified that CADM1_CADM1 played an essential role in the progression of PTC for the first time and our findings provide a new potential prognostic and therapeutic ligand-receptor pair for advanced PTC.

Functional and Clinical Characteristics of Cell Adhesion Molecule CADM1 in Cancer

The cell adhesion molecule CADM1, which participates in cell adhesion and signal transduction, has a regulatory effect on the development of tumors. CADM1 is often involved in malignant tumors of multiple organ systems, such as the respiratory and digestive systems. Upregulated CADM1 promotes tumor cell apoptosis and inhibits malignant proliferation. Along with cell cycle-related proteins, it participates in regulating signaling pathways, such as EMT, STAT3, and AKT, and plays an important role in inhibiting invasion and migration. Considering clinical characteristics, low CADM1 expression is associated with aggressive tumors and poor prognosis. In addition, some long non-coding RNAs (lncRNAs) or miRNAs directly or indirectly act on CADM1 to regulate tumor growth and motility. Interestingly, CADM1 function differs in adult T-cell leukemia/lymphoma (ATLL), and NF-κB is thought to be involved in this process. Taken together, CADM1 could be a potential biomarker for early diagnosis and a target for cancer treatment in future clinical practices.

CADM1 promotes malignant features of small-cell lung cancer by recruiting 4.1R to the plasma membrane

Cell adhesion molecule 1 (CADM1), which mediates intercellular adhesion between epithelial cells, is shown to be highly expressed in small-cell lung cancer (SCLC) and to enhance tumorigenicity of SCLC cells in nude mice. Here, we investigated the molecular mechanism underlying the oncogenic role of CADM1 in SCLC. CADM1 promoted colony formation of SCLC cells in soft agar. Analysis of deletion and point mutants of the conserved protein-binding motifs in CADM1 revealed that the 4.1 protein-binding motif in the cytoplasmic domain is responsible for the promotion of colony formation. Among the actin-binding 4.1 proteins, 4.1R was the only protein whose localization to the plasma membrane is dependent on CADM1 expression in SCLC cells. Knockdown of 4.1R suppressed the colony formation enhanced by CADM1, suggesting that 4.1R is required for the oncogenic role of CADM1 in SCLC. In primary SCLC, CADM1 expression was correlated with membranous localization of 4.1R, as was observed in a SCLC cell line. Moreover, membranous co-localization of CADM1 and 4.1R was associated with more advanced tumor stage. These results suggest that the formation of CADM1-4.1R complex would promote malignant features of SCLC.

The Role of Cell Adhesion Molecule 1 (CADM1) in Cutaneous Malignancies

Cell adhesion ability is one of the components to establish cell organization and shows a great contribution to human body construction consisting of various types of cells mixture to orchestrate tissue specific function. The cell adhesion molecule 1 (CADM1) is a molecule of cell adhesion with multiple functions and has been identified as a tumor suppressor gene. CADM1 has multifunctions on the pathogenesis of malignancies, and other normal cells such as immune cells. However, little is known about the function of CADM1 on cutaneous cells and cutaneous malignancies. CADM1 plays an important role in connecting cells with each other, contacting cells to deliver their signal, and acting as a scaffolding molecule for other immune cells to develop their immune responses. A limited number of studies reveal the contribution of CADM1 on the development of cutaneous malignancies. Solid cutaneous malignancies, such as cutaneous squamous cell carcinoma and malignant melanoma, reduce their CADM1 expression to promote the invasion and metastasis of the tumor. On the contrary to these cutaneous solid tumors except for Merkel cell carcinoma, cutaneous lymphomas, such as adult-T cell leukemia/lymphoma, mycosis fungoides, and Sézary syndrome, increase their CADM1 expression for the development of tumor environment. Based on the role of CADM1 in the etiology of tumor development, the theory of CADM1 contribution will desirably be applied to skin tumors according to other organ malignancies, however, the characteristics of skin as a multicomponent peripheral organ should be kept in mind to conclude their prognoses.

Not Just Another Scaffolding Protein Family: The Multifaceted MPPs

Membrane palmitoylated proteins (MPPs) are a subfamily of a larger group of multidomain proteins, namely, membrane-associated guanylate kinases (MAGUKs). The ubiquitous expression and multidomain structure of MPPs provide the ability to form diverse protein complexes at the cell membranes, which are involved in a wide range of cellular processes, including establishing the proper cell structure, polarity and cell adhesion. The formation of MPP-dependent complexes in various cell types seems to be based on similar principles, but involves members of different protein groups, such as 4.1-ezrin-radixin-moesin (FERM) domain-containing proteins, polarity proteins or other MAGUKs, showing their multifaceted nature. In this review, we discuss the function of the MPP family in the formation of multiple protein complexes. Notably, we depict their significant role for cell physiology, as the loss of interactions between proteins involved in the complex has a variety of negative consequences. Moreover, based on recent studies concerning the mechanism of membrane raft formation, we shed new light on a possible role played by MPPs in lateral membrane organization.

PAK Kinase Inhibition Has Therapeutic Activity in Novel Preclinical Models of Adult T-Cell Leukemia/Lymphoma

PURPOSE

To evaluate therapeutic activity of PAK inhibition in ATLL and to characterize the role of PAK isoforms in cell proliferation, survival, and adhesion of ATLL cells in preclinical models.

EXPERIMENTAL DESIGN

Frequency and prognostic impact of PAK2 amplification were evaluated in an ATLL cohort of 370 cases. Novel long-term cultures and in vivo xenograft models were developed using primary ATLL cells from North American patients. Two PAK inhibitors were used to block PAK kinase activity pharmacologically. siRNA-based gene silencing approach was used to genetically knockdown (KD) PAK1 and PAK2 in ATLL cell lines.

RESULTS

PAK1/2/4 are the three most abundantly expressed PAK family members in ATLL. PAK2 amplifications are seen in 24% of ATLLs and are associated with worse prognosis in a large patient cohort. The pan-PAK inhibitor PF-3758309 (PF) has strong in vitro and in vivo activity in a variety of ATLL preclinical models. These activities of PF are likely attributed to its ability to target several PAK isoforms simultaneously because genetic silencing of either PAK1 or PAK2 produced more modest effects. PAK2 plays a major role in CADM1-mediated stromal interaction, which is an important step in systemic dissemination of the disease. This finding is consistent with the observation that PAK2 amplification is more frequent in aggressive ATLLs and correlates with inferior outcome.

CONCLUSIONS

PAK2, a gene frequently amplified in ATLL, facilitates CADM1-mediated stromal interaction and promotes survival of ATLL cells. Taken together, PAK inhibition may hold significant promise as a targeted therapy for aggressive ATLLs.

miR-20b, miR-296, and Let-7f Expression in Human Adipose Tissue is Related to Obesity and Type 2 Diabetes

OBJECTIVE

This study aimed to analyze the potential association of different microRNA (miRNA) molecules with both type 2 diabetes (T2D) and obesity and determine their target genes.

METHODS

Quantitative PCR was used to analyze the miR-20b, miR-296, and Let-7f levels in human visceral and subcutaneous adipose tissues (ATs) in relation to obesity and T2D, miRTarBase 4.0 was used for validation of target genes, and the Protein Analysis Through Evolutionary Relationships (PANTHER) Classification System and the Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to annotate the biological processes of the predicted targets.

RESULTS

In AT, miR-20b, miR-296, and Let-7f levels were significantly different between normoglycemic subjects and those with T2D. In visceral adipose tissue, miRNA levels were higher in normoglycemic/obesity samples than in T2D/obesity samples. miR-20b-miR-296 and Let-7f target genes that showed significant differences in both ATs in relation to obesity and T2D were CDKN1A, CX3CL1, HIF1A, PPP2R1B, STAT3, and VEGFA. These genes are known to be principally involved in the vascular endothelial growth factor (VEGF) and WNT pathways.

CONCLUSIONS

This study provides experimental evidence of the possible correlation between AT miR-20b-miR-296-Let-7f with obesity and T2D, which might involve vascular endothelial growth factor and WNT-dependent pathways that are regulated by six different genes, suggesting a novel signaling pathway that could be important for understanding the mechanisms underlying the AT dysfunction associated with obesity and T2D.

Quantitative Analysis of Interaction Between CADM1 and Its Binding Cell-Surface Proteins Using Surface Plasmon Resonance Imaging

The cell adhesion molecule (CADM) family of the immunoglobulin superfamily (IgSF) comprises four members, CADM1-CADM4, and participates in the formation of epithelial and synaptic adhesion through cell-cell homophilic and heterophilic interactions. To identify the partners that interact with each member of the CADM family proteins, we set up a platform for multiple detection of the extracellular protein-protein interactions using surface plasmon resonance imaging (SPRi) and analyzed the interactions between the CADM family proteins and 10 IgSF of their structurally related cell adhesion molecules. SPRi analysis identified a new interaction between CADM1 and CADM4, where this heterophilic interaction was shown to be involved in morphological spreading of adult T-cell leukemia (ATL) cells expressing CADM1 when incubated on CADM4-coated glass. Moreover, class-I MHC-restricted T-cell-associated molecule (CRTAM) was identified to show the highest affinity to CADM1 among its binding partners by comparing the dissociation constants calculated from the SPR sensorgrams. These results suggest that the SPRi platform would provide a novel screening tool to characterize extracellular protein-protein interactions among cell-surface and secreted proteins, including IgSF molecules.

miR-214-3p promotes the proliferation, migration and invasion of osteosarcoma cells by targeting CADM1

Although osteosarcoma (OS) is the most common type of primary bone tumor in adolescents and young adults, its mechanism remains unclear. A previous study by the authors demonstrated that miR-214-3p was upregulated in OS patients. Therefore, the present study aimed to investigate the effect and molecular mechanism of miR-214-3p in OS cells. OS cell lines, U2OS and MNNG/HOS Cl#5, were transiently transfected with miR-214-3p mimics, a control mimic, miR-214-3p inhibitors and a control inhibitor. Subsequent assays revealed that elevated miR-214-3p promoted the proliferative, migratory and invasive abilities of OS cells, while the opposite effects were observed in cells that were transfected with miR-214-3p inhibitors. The interaction between miR-214-3p and cell adhesion molecule 1 (CADM1) 3'untranslated region (UTR) was verified by a dual luciferase assay, which indicated that the relative luciferase activity was decreased in 293T cells that were co-transfected with miR-214-3p mimic and psiCHECK2-CADM1-3'UTR compared with cells that were co-transfected with psiCHECK2-CADM1-3'UTR and control mimic. The knockdown of CADM1 using small-interfering RNA enhanced the proliferative, migratory and invasive abilities of OS cells. Furthermore, downregulated CADM1 expression increased the expression of phosphorylated P44/42 mitogen activated kinase (MAPK). In conclusion, miR-214-3p was able to directly target CADM1 and decrease its expression. This resulted in the activation of the P44/42 MAPK signaling pathway, and thereby promoted the proliferation, migration and invasion of OS cells.

Cell adhesion molecule-1 shedding induces apoptosis of renal epithelial cells and exacerbates human nephropathies

Chronic kidney disease (CKD) is an important problem throughout the world, associated with the increase of blood urea nitrogen (BUN) and serum creatinine (sCre) and with renal tubular injuries. It is crucial to elucidate the molecular mechanisms of renal injuries to identify the new therapeutics and early diagnostic methods. We focused on cell adhesion molecule-1 (CADM1) protein. CADM1, its isoform SP4, is expressed in the epithelial cells of various tissues, including renal distal tubules, localized on the lateral cell membrane, mediates cell-cell adhesion via trans-homophilic binding, and interacts with various proteins. We previously reported that its expression was downregulated by post-proteolytic cleavage (α- and β-shedding) in pulmonary diseases. To investigate whether CADM1 α-shedding occurs in human nephropathies, we performed Western blotting and immunohistochemical analysis of specimens with arterionephrosclerosis (AS) and diabetic nephropathy (DN) from autopsied kidneys. CADM1 α-shedding was induced in AS and DN kidneys and derived from the decrease in full-length CADM1 (FL-CADM1) and increase of the COOH-terminal fragment (α-CTF). In particular, the reduced FL-CADM1 level was correlated with tubular and tubulointerstitial injuries and the increases in BUN and sCre levels. Apoptosis of renal tubular epithelial cells (TECs) was promoted in both nephropathies, and it was significantly correlated with the decrease in the FL-CADM1. Furthermore, FL-CADM1 knockdown by small interfering RNA downregulated anti-apoptotic Bcl-2 protein and promoted apoptosis of cultured renal TECs. The present study suggests that the reduction of FL-CADM1 leads to renal TEC apoptosis and could exacerbate renal tubular and tubulointerstitial injuries, which contribute to the development of CKD.

Epithelial-mesenchymal transition leads to NK cell-mediated metastasis-specific immunosurveillance in lung cancer

During epithelial-mesenchymal transition (EMT) epithelial cancer cells transdifferentiate into highly motile, invasive, mesenchymal-like cells, giving rise to disseminating tumor cells. Few of these disseminated cells successfully metastasize. Immune cells and inflammation in the tumor microenvironment were shown to drive EMT, but few studies investigated the consequences of EMT for tumor immunosurveillance. In addition to initiating metastasis, we demonstrate that EMT confers increased susceptibility to natural killer (NK) cells and contributes, in part, to the inefficiency of the metastatic process. Depletion of NK cells allowed spontaneous metastasis without affecting primary tumor growth. EMT-induced modulation of E-cadherin and cell adhesion molecule 1 (CADM1) mediated increased susceptibility to NK cytotoxicity. Higher CADM1 expression correlates with improved patient survival in 2 lung and 1 breast adenocarcinoma patient cohorts and decreased metastasis. Our observations reveal a novel NK-mediated, metastasis-specific immunosurveillance in lung cancer and present a window of opportunity for preventing metastasis by boosting NK cell activity.

A data mining approach for identifying pathway-gene biomarkers for predicting clinical outcome: A case study of erlotinib and sorafenib

A novel data mining procedure is proposed for identifying potential pathway-gene biomarkers from preclinical drug sensitivity data for predicting clinical responses to erlotinib or sorafenib. The analysis applies linear ridge regression modeling to generate a small (N~1000) set of baseline gene expressions that jointly yield quality predictions of preclinical drug sensitivity data and clinical responses. Standard clustering of the pathway-gene combinations from gene set enrichment analysis of this initial gene set, according to their shared appearance in molecular function pathways, yields a reduced (N~300) set of potential pathway-gene biomarkers. A modified method for quantifying pathway fitness is used to determine smaller numbers of over and under expressed genes that correspond with favorable and unfavorable clinical responses. Detailed literature-based evidence is provided in support of the roles of these under and over expressed genes in compound efficacy. RandomForest analysis of potential pathway-gene biomarkers finds average treatment prediction errors of 10% and 22%, respectively, for patients receiving erlotinib or sorafenib that had a favorable clinical response. Higher errors were found for both compounds when predicting an unfavorable clinical response. Collectively these results suggest complementary roles for biomarker genes and biomarker pathways when predicting clinical responses from preclinical data.

Receptor FGFRL1 acts as a tumor suppressor in nude mice when overexpressed in HEK 293 Tet-On cells

Fibroblast growth factor receptor-like 1 (FGFRL1) is a transmembrane receptor that interacts with heparin and FGF ligands. In contrast to the classical FGF receptors, FGFR1 to FGFR4, it does not appear to affect cell growth and proliferation. In the present study, an inducible gene expression system was utilized in combination with a xenograft tumor model to investigate the effects of FGFRL1 on cell adhesion and tumor formation. It was determined that recombinant FGFRL1 promotes the adhesion of HEK 293 Tet-On® cells in vitro. Moreover, when such cells are induced to express FGFRL1ΔC they aggregate into huge clusters. If injected into nude mice, the cells form large tumors. Notably, this tumor growth is completely inhibited when the expression of FGFRL1 is induced. The forced expression of FGFRL1 in the tumor tissue may restore contact inhibition, thereby preventing growth of the cells in nude mice. The results of the present study demonstrate that FGFRL1 acts as a tumor suppressor similar to numerous other cell adhesion proteins. It is therefore likely that FGFRL1 functions as a regular cell-cell adhesion protein.

Immunohistochemical study of the membrane skeletal protein, membrane protein palmitoylated 6 (MPP6), in the mouse small intestine

The membrane protein palmitoylated (MPP) family belongs to the membrane-associated guanylate kinase (MAGUK) family. MPP1 interacts with the protein 4.1 family member, 4.1R, as a membrane skeletal protein complex in erythrocytes. We previously described the interaction of another MPP family, MPP6, with 4.1G in the mouse peripheral nervous system. In the present study, the immunolocalization of MPP6 in the mouse small intestine was examined and compared with that of E-cadherin, zonula occludens (ZO)-1, and 4.1B, which we previously investigated in intestinal epithelial cells. The immunolocalization of MPP6 was also assessed in the small intestines of 4.1B-deficient (-/-) mice. In the small intestine, Western blotting revealed that the molecular weight of MPP6 was approximately 55-kDa, and MPP6 was immunostained under the cell membranes in the basolateral portions of almost all epithelial cells from the crypts to the villi. The immunostaining pattern of MPP6 in epithelial cells was similar to that of E-cadherin, but differed from that of ZO-1. In intestinal epithelial cells, the immunostained area of MPP6 was slightly different from that of 4.1B, which was restricted to the intestinal villi. The immunolocalization of MPP6 in small intestinal epithelial cells was similar between 4.1B(-/-) mice and 4.1B(+/+) mice. In the immunoprecipitation study, another MAGUK family protein, calcium/calmodulin-dependent serine protein kinase (CASK), was shown to molecularly interact with MPP6. Thus, we herein showed the immunolocalization and interaction proteins of MPP6 in the mouse small intestine, and also that 4.1B in epithelial cells was not essential for the sorting of MPP6.

The role of the PI3K/Akt/mTOR signalling pathway in human cancers induced by infection with human papillomaviruses

Infection with Human papillomaviruses (HPVs) leads to the development of a wide-range of cancers, accounting for 5% of all human cancers. A prominent example is cervical cancer, one of the leading causes of cancer death in women worldwide. It has been well established that tumor development and progression induced by HPV infection is driven by the sustained expression of two oncogenes E6 and E7. The expression of E6 and E7 not only inhibits the tumor suppressors p53 and Rb, but also alters additional signalling pathways that may be equally important for transformation. Among these pathways, the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signalling cascade plays a very important role in HPV-induced carcinogenesis by acting through multiple cellular and molecular events. In this review, we summarize the frequent amplification of PI3K/Akt/mTOR signals in HPV-induced cancers and discuss how HPV oncogenes E6/E7/E5 activate the PI3K/Akt/mTOR signalling pathway to modulate tumor initiation and progression and affect patient outcome. Improvement of our understanding of the mechanism by which the PI3K/Akt/mTOR signalling pathway contributes to the immortalization and carcinogenesis of HPV-transduced cells will assist in devising novel strategies for preventing and treating HPV-induced cancers.

Dynamic regulation of a cell adhesion protein complex including CADM1 by combinatorial analysis of FRAP with exponential curve-fitting

Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10 min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation.

Neuron membrane trafficking and protein kinases involved in autism and ADHD

A brain-enriched multi-domain scaffolding protein, neurobeachin has been identified as a candidate gene for autism patients. Mutations in the synaptic adhesion protein cell adhesion molecule 1 (CADM1) are also associated with autism spectrum disorder, a neurodevelopmental disorder of uncertain molecular origin. Potential roles of neurobeachin and CADM1 have been suggested to a function of vesicle transport in endosomal trafficking. It seems that protein kinase B (AKT) and cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) have key roles in the neuron membrane trafficking involved in the pathogenesis of autism. Attention deficit hyperactivity disorder (ADHD) is documented to dopaminergic insufficiencies, which is attributed to synaptic dysfunction of dopamine transporter (DAT). AKT is also essential for the DAT cell-surface redistribution. In the present paper, we summarize and discuss the importance of several protein kinases that regulate the membrane trafficking involved in autism and ADHD, suggesting new targets for therapeutic intervention.