Evidence for Critical Role of Lymphocyte Cytosolic Protein 1 in Oral Cancer

Proteomic profiling of formalin-fixed paraffine-embedded tissue reveals key proteins related to lung dysfunction in idiopathic pulmonary fibrosis

Introduction

Idiopathic pulmonary fibrosis (IPF) severely affects the lung leading to aberrant deposition of extracellular matrix and parenchymal stiffness with progressive functional derangement. The limited availability of fresh tissues represents one of the major limitations to study the molecular profiling of IPF lung tissue. The primary aim of this study was to explore the proteomic profiling yield of archived formalin-fixed paraffin-embedded (FFPE) specimens of IPF lung tissues.

Methods

We further determined the protein expression according to respiratory functional decline at the time of biopsy. The total proteins isolated from 11 FFPE samples of IPF patients compared to 3 FFPE samples from a non-fibrotic lung defined as controls, were subjected to label-free quantitative proteomic analysis by liquid chromatography-mass spectrometry (LC-MS/MS) and resulted in the detection of about 400 proteins.

Results

After the pairwise comparison between controls and IPF, functional enrichment analysis identified differentially expressed proteins that were involved in extracellular matrix signaling pathways, focal adhesion and transforming growth factor β (TGF-β) signaling pathways strongly associated with IPF onset and progression. Five proteins were significantly over- expressed in the lung of IPF patients with either advanced disease stage (Stage II) or impaired pulmonary function (FVC<75, DLCO<55) compared to controls; these were lymphocyte cytosolic protein 1 (LCP1), peroxiredoxin-2 (PRDX2), transgelin 2 (TAGLN2), lumican (LUM) and mimecan (OGN) that might play a key role in the fibrogenic processes.

Discussion

Our work showed that the analysis of FFPE samples was able to identify key proteins that might be crucial for the IPF pathogenesis. These proteins are correlated with lung carcinogenesis or involved in the immune landscape of lung cancer, thus making possible common mechanisms between lung carcinogenesis and fibrosis progression, two pathological conditions at risk for each other in the real life.

Identification of Immune Infiltrating Cell-Related Biomarkers in Early Gastric Cancer Progression

OBJECTIVES

Gastric cancer (GC) is one of the most prevalent malignancies worldwide, and early detection is crucial for improving patient survival rates. We aimed to identify immune infiltrating cell-related biomarkers in early gastric cancer (EGC) progression.

METHODS

The GSE55696 and GSE130823 datasets with low-grade intraepithelial neoplasia (LGIN), high-grade intraepithelial neoplasia (HGIN), and EGC samples were downloaded from the Gene Expression Omnibus database to perform an observational study. Immune infiltration analysis was performed by single sample gene set enrichment analysis and Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data. Weighted gene co-expression network analysis was used to explore the co-expression modules and genes, and further enrichment analysis was performed on these genes. A protein-protein interaction (PPI) network of these genes was constructed to identify biomarkers associated with EGC progression. Screened hub genes were validated by the rank sum test and reverse transcription quantitative polymerase chain reaction.

RESULTS

Immune scores were significantly elevated in EGC samples compared to LGIN and HGIN samples. The green-yellow module exhibited the strongest correlation with both immune score and disease progression. The 87 genes within this module were associated with the chemokine signaling pathways, the PI3K-Akt signaling pathways, leukocyte transendothelial migration, and Ras signaling pathways. Through PPI network analysis, the hub genes identified were protein tyrosine phosphatase receptor-type C (PTPRC), pleckstrin, CD53, CD48, lymphocyte cytosolic protein 1 (LCP1), hematopoietic cell-specific Lyn substrate 1, IKAROS Family Zinc Finger 1, Bruton tyrosine kinase, and Vav guanine nucleotide exchange factor 1. Notably, CD48, LCP1, and PTPRC showed high expression levels in EGC samples, with the remaining hub genes demonstrating a similar expression trend.

CONCLUSION

This study identified 9 immune cell-related biomarkers that may be actively involved in the progression of EGC and serve as potential targets for GC diagnosis and treatment.

LCP1 knockdown in monocyte-derived macrophages: mitigating ischemic brain injury and shaping immune cell signaling and metabolism

Rationale: Ischemic stroke poses a significant health burden with limited treatment options. Lymphocyte Cytosolic Protein 1 (LCP1) facilitates cell migration and immune responses by aiding in actin polymerization, cytoskeletal rearrangements, and phagocytosis. We have demonstrated that the long non-coding RNA (lncRNA) Maclpil silencing in monocyte-derived macrophages (MoDMs) led to LCP1 inhibition, reducing ischemic brain damage. However, the role of LCP1 of MoDMs in ischemic stroke remains unknown. Methods and Results: We investigated the impact of LCP1 on ischemic brain injury and immune cell signaling and metabolism. We found that knockdown of LCP1 in MoDMs demonstrated robust protection against ischemic infarction and improved neurological behaviors in mice. Utilizing the high-dimensional CyTOF technique, we demonstrated that knocking down LCP1 in MoDMs led to a reduction in neuroinflammation and attenuation of lymphopenia, which is linked to immunodepression. It also showed altered immune cell signaling by modulating the phosphorylation levels of key kinases and transcription factors, including p-PLCg2, p-ERK1/2, p-EGFR, p-AKT, and p4E-BP1 as well as transcription factors like p-STAT1, p-STAT3, and p-STAT4. Further bioinformatic analysis indicated that Akt and EGFR are particularly involved in fatty acid metabolism and glycolysis. Indeed, single-cell sequencing analysis confirmed that enrichment of fatty acid and glycolysis metabolism in Lcp1high monocytes/macrophages. Furthermore, Lcp1high cells exhibited enhanced oxidative phosphorylation, chemotaxis, migration, and ATP biosynthesis pathways. In vitro experiments confirmed the role of LCP1 in regulating mitochondrial function and fatty acid uptake. Conclusions: These findings contribute to a deeper understanding of LCP1 in the context of ischemic stroke and provide valuable insights into potential therapeutic strategies targeting LCP1 and metabolic pathways, aiming to attenuating neuroinflammation and lymphopenia.

Extracellular Vesicle-Based Drug Delivery Systems for Head and Neck Squamous Cell Carcinoma: A Systematic Review

It is estimated that there are over 890,000 new cases of head and neck squamous cell carcinoma (HNSCC) worldwide each year, accounting for approximately 5% of all cancer cases. Current treatment options for HNSCC often cause significant side effects and functional impairments, thus there is a challenge to discover more acceptable treatment technologies. Extracellular vesicles (EVs) can be utilized for HNSCC treatment in several ways, for example, for drug delivery, immune modulation, as biomarkers for diagnostics, gene therapy, or tumor microenvironment modulation. This systematic review summarizes new knowledge regarding these options. Articles published up to 11 December 2022, were identified by searching the electronic databases PubMed/MEDLINE, Scopus, Web of Science, and Cochrane. Only full-text original research papers written in English were considered eligible for analysis. The quality of studies was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool for Human and Animal Studies, modified for the needs of this review. Of 436 identified records, 18 were eligible and included. It is important to note that the use of EVs as a treatment for HNSCC is still in the early stages of research, so we summarized information on challenges such as EV isolation, purification, and standardization of EV-based therapies in HNSCC.

Inhibition of the Glycolysis Prevents the Cerebral Infarction Progression Through Decreasing the Lactylation Levels of LCP1

Cerebral infarction (CI), also known as ischemic stroke, has a high incidence rate and mortality rate. The purpose of this study was to investigate the potential effect and mechanism of Lymphocyte cytosolic protein 1 (LCP1) in the CI progression. The middle cerebral artery occlusion (MCAO) treated rats and oxygen–glucose deprivation/reoxygenation (OGD/R) stimulated PC12 cells were used to establish CI model in vivo and in vitro. The cell proliferation and apoptosis was determined by CCK-8 assay and flow cytometry, respectively. Immunoprecipitation and western blot was performed to test the lactylation levels of LCP1. The cells were treated with cycloheximide to determined the protein stability of LCP1. The glucose uptake and lactate production was determined with commercial kits. The extracellular acidification rate were evaluated by Seahorse. The results showed that LCP1 was upregulated in the MCAO rats and OGD/R stimulated PC12 cells. LCP1 knockdown dramatically decreased the neurological score, infarct volume and the brain water content of MCAO rats. Besides, LCP1 knockdown promoted the cell viability while decreased the apoptosis rate of the OGD/R stimulated PC12 cells. Additionally, the global lactylation and lactylation levels of LCP1 was prominently enhanced in vivo and in vitro in cerebral infarction. 2-DG treatment prominently decreased it. In conclusion, inhibiting the glycolysis decreased the lactylation levels of LCP1 and resulted in the degradation of LCP1, which eventually relieved the CI progression.

Targeted proteomics using parallel reaction monitoring confirms salivary proteins indicative of metastatic triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype due to the absence of hormonal receptors. Our study aimed to identify and determine the effectiveness of salivary proteins as candidate markers for metastatic TNBC subtype using parallel reaction monitoring mass spectrometry (PRM-MS). Three salivary proteins (lipocalin-1, SMR3B, and plastin-2) that showed significant differential expression in label-free quantitation (LFQ) between TNBC (N = 6) and health subjects (HS; N = 6) were selected for further validation. The developed PRM assay was used to quantify peptides GLST and NNLE (lipocalin-1), VYAL and MINL (Plastin-2) and GPYP, and IPPP (SMR3B) on a different cohort of TNBC patients (N = 20) and HS (N = 20) for evaluating their discriminating performances. Quantitative validation using PRM correlated well with the LFQ results, and 5 peptides from three proteins showed a similar up-or down-regulation. Subsequently, these proteins were validated by Western blot analysis. Compared to one protein's performance as an individual marker, the five-signature panel with salivary GLST, VYAL, MINL, GPYP, and IPPP achieved better performance in differentiating aggressive TNBC and HS with sensitivity (80%) and specificity (95%). Targeted proteomic analysis of the prioritized proteins highlights a peptide-based signature in saliva as the potential predictor to distinguish between TNBC and HS. SIGNIFICANCE OF THE STUDY: This study was designed to identify and quantify potential markers in saliva from the triple-negative breast cancer (TNBC) patients using parallel reaction monitoring assay. Three salivary proteins, Lipocalin-1 (LCN-1), Submaxillary androgen-regulated protein 3B (SMR3B), and Plastin-2 (LCP-1) selected in the discovery-phase were further quantified by targeted proteomics and Western blots. The salivary proteins successfully differentiated TNBC patients from healthy subjects with a sensitivity (80%) and specificity (95%).

Phospho-proteomics reveals that RSK signaling is required for proliferation of natural killer cells stimulated with IL-2 or IL-15

Natural killer (NK) cells are cytotoxic lymphocytes that play a critical role in the innate immune system. Although cytokine signaling is crucial for the development, expansion, and cytotoxicity of NK cells, the signaling pathways stimulated by cytokines are not well understood. Here, we sought to compare the early signaling dynamics induced by the cytokines interleukin (IL)-2 and IL-15 using liquid chromatography-mass spectrometry (LC-MS)-based phospho-proteomics. Following stimulation of the immortalized NK cell line NK-92 with IL-2 or IL-15 for 5, 10, 15, or 30 min, we identified 8,692 phospho-peptides from 3,023 proteins. Comparing the kinetic profiles of 3,619 fully quantified phospho-peptides, we found that IL-2 and IL-15 induced highly similar signaling in NK-92 cells. Among the IL-2/IL-15-regulated phospho-peptides were both well-known signaling events like the JAK/STAT pathway and novel signaling events with potential functional significance including LCP1 pSer5, STMN1 pSer25, CHEK1 pSer286, STIM1 pSer608, and VDAC1 pSer104. Using bioinformatic approaches, we sought to identify kinases regulated by IL-2/IL-15 stimulation and found that the p90 ribosomal S6 kinase (p90RSK) family was activated by both cytokines. Using pharmacological inhibitors, we then discovered that RSK signaling is required for IL-2 and IL-15-induced proliferation in NK-92 cells. Taken together, our analysis represents the first phospho-proteomic characterization of cytokine signaling in NK cells and increases our understanding of how cytokine signaling regulates NK cell function.

Transcriptome Profiling Analysis Identifies LCP1 as a Contributor for Chidamide Resistance in Gastric Cancer

BACKGROUND

Gastric cancer (GC) remains a significant health problem and carries with it substantial morbidity and mortality. Chidamide is a novel and orally administered histone deacetylase (HDAC) inhibitor and has been demonstrated its anti-tumor efficacy on different kinds of hematological and solid tumors. However, the underlying mechanism of chidamide resistance is still poorly characterized.

METHODS

We established chidamide resistant GC cell lines, AGS ChiR and MGC803 ChiR and investigated the toxicologic effects through cell survival, colony formation and flow cytometry assays in vitro, and a subcutaneous xenograft model in vivo. RNA-sequence was then performed to screen chidamide resistance-associated genes between AGS and AGS ChiR cells. The role of Lymphocyte cytosolic protein 1 (LCP1) in chidamide resistance was explored by gain- and loss-of-function analyses.

RESULTS

We found that chidamide significantly inhibited cell proliferation and induced the apoptosis in a concentration-dependent manner in wild-type GC cell lines as compared to chidamide resistant cell lines. The transcriptomic profiling, quantitative RT-PCR, and western blot data revealed that LCP1 was upregulated in AGS ChiR cells compared with parental cells. Overexpression of LCP1 conferred and knockdown of LCP1 attenuated the chidamide resistance of GC cells. Epigenetic derepression of LCP1 by chidamide may be a possible reason for the contribution of LCP1 to chidamide resistance.

CONCLUSIONS

These findings illustrated that LCP1 may play a chidamide resistance role in GC, suggesting that LCP1 could be a potential target for the therapy of GC combined with chidamide.

Lymphocyte cytosolic protein 1 (L-plastin) I232F mutation impairs granulocytic proliferation and causes neutropenia

Neutrophils migrate into inflamed tissue, engage in phagocytosis, and clear pathogens or apoptotic cells. These processes require well-coordinated events involving the actin cytoskeleton. We describe a child with severe neutropenia and episodes of soft tissue infections and pneumonia. Bone marrow examination showed granulocytic hypoplasia with dysplasia. Whole-exome sequencing revealed a de novo heterozygous missense mutation in LCP1, which encodes the F-actin-binding protein Lymphocyte Cytosolic Protein 1. To determine its pathophysiological significance, we stably transduced cells with doxycycline-inducible wild-type LCP1 and LCP1 I232F lentiviral constructs. We observed dysplastic granulocytic 32D cells expressing LCP1 I232F cells. These cells showed decreased proliferation without a block in differentiation. In addition, expression of LCP1 I232F resulted in a cell cycle arrest at the G2/M phase, but it did not lead to increased levels of genes involved in apoptosis or the unfolded protein response. Both 32D and HeLa cells expressing mutant LCP1 displayed impaired cell motility and invasiveness. Flow cytometry showed increased F-actin. However, mutant LCP1-expressing 32D cells exhibited normal oxidative burst upon stimulation. Confocal imaging and subcellular fractionation revealed diffuse intracellular localization of LCP1, but only the mutant form was found in the nucleus. We conclude that LCP1 is a new gene involved in granulopoiesis, and the missense variant LCP1 I232F leads to neutropenia and granulocytic dysplasia with aberrant actin dynamics. Our work supports a model of neutropenia due to aberrant actin regulation.

Aberrant GIMAP2 expression affects oral squamous cell carcinoma progression by promoting cell cycle and inhibiting apoptosis

GTPases of immunity-associated protein 2 (GIMAP2) is a GTPase family member associated with T cell survival. However, its mechanisms of action in oral squamous cell carcinoma (OSCC) remain largely unknown. Therefore, the present study aimed to elucidate the possible role of GIMAP2 in OSCC development by investigating its expression levels and molecular mechanisms in OSCC. Reverse transcription quantitative PCR, immunoblotting and immunohistochemistry indicated that GIMAP2 expression was significantly upregulated (P<0.05) in OSCC-derived cell lines and primary OSCC specimens compared with that in their normal counterparts. GIMAP2-knockdown OSCC cells exhibited decreased cell growth, which was associated with cyclin-dependent kinase (CDK)4, CDK6 and phosphorylated Rb downregulation and p53 and p21 upregulation. In addition to cell cycle arrest, GIMAP2 affected anti-apoptotic functions in GIMAP2-knockdown cells by upregulating Bcl-2 and downregulating Bax and Bak. These findings indicated that GIMAP2 may significantly influence OSCC development and apoptosis inhibition and thus is a potential biomarker of OSCC.

New Proteins Contributing to Immune Cell Infiltration and Pannus Formation of Synovial Membrane from Arthritis Diseases

An inflamed synovial membrane plays a major role in joint destruction and is characterized by immune cells infiltration and fibroblast proliferation. This proteomic study considers the inflammatory process at the molecular level by analyzing synovial biopsies presenting a histological inflammatory continuum throughout different arthritis joint diseases. Knee synovial biopsies were obtained from osteoarthritis (OA; n = 9), chronic pyrophosphate arthropathy (CPPA; n = 7) or rheumatoid arthritis (RA; n = 8) patients. The histological inflammatory score was determined using a semi-quantitative scale based on synovial hyperplasia, lymphocytes, plasmocytes, neutrophils and macrophages infiltration. Proteomic analysis was performed by liquid chromatography-mass spectrometry (LC-MS/MS). Differentially expressed proteins were confirmed by immunohistochemistry. Out of the 1871 proteins identified and quantified by LC-MS/MS, 10 proteins (LAP3, MANF, LCP1, CTSZ, PTPRC, DNAJB11, EML4, SCARA5, EIF3K, C1orf123) were differentially expressed in the synovial membrane of at least one of the three disease groups (RA, OA and CPPA). Significant increased expression of the seven first proteins was detected in RA and correlated to the histological inflammatory score. Proteomics is therefore a powerful tool that provides a molecular pattern to the classical histology usually applied for synovitis characterization. Except for LCP1, CTSZ and PTPRC, all proteins have never been described in human synovitis.

Engineered exosomes delivering specific tumor-suppressive RNAi attenuate oral cancer progression

Exosomes are involved in a wide range of biological processes in human cells. Considerable evidence suggests that engineered exosomes (eExosomes) containing therapeutic agents can attenuate the oncogenic activity of human cancer cells. Despite its biomedical relevance, no information has been available for oral squamous cell carcinoma (OSCC), and therefore the development of specific OSCC-targeting eExosomes (octExosomes) is urgently needed. We demonstrated that exosomes from normal fibroblasts transfected with Epstein-Barr Virus Induced-3 (EBI3) cDNA were electroporated with siRNA of lymphocyte cytoplasmic protein 1 (LCP1), as octExosomes, and a series of experiments were performed to evaluate the loading specificity/effectiveness and their anti-oral cancer cell activities after administration of octExosomes. These experiments revealed that octExosomes were stable, effective for transferring siLCP1 into OSCC cells and LCP1 was downregulated in OSCC cells with octExosomes as compared with their counterparts, leading to a significant tumor-suppressive effect in vitro and in vivo. Here we report the development of a new valuable tool for inhibiting tumor cells. By engineering exosomes, siLCP1 was transferred to specifically suppress oncogenic activity of OSCC cells. Inhibition of other types of human malignant cells merits further study.

Human-specific polymorphic pseudogenization of SIGLEC12 protects against advanced cancer progression

Compared with our closest living evolutionary cousins, humans appear unusually prone to develop carcinomas (cancers arising from epithelia). The SIGLEC12 gene, which encodes the Siglec-XII protein expressed on epithelial cells, has several uniquely human features: a fixed homozygous missense mutation inactivating its natural ligand recognition property; a polymorphic frameshift mutation eliminating full-length protein expression in ~60%-70% of worldwide human populations; and, genomic features suggesting a negative selective sweep favoring the pseudogene state. Despite the loss of canonical sialic acid binding, Siglec-XII still recruits Shp2 and accelerates tumor growth in a mouse model. We hypothesized that dysfunctional Siglec-XII facilitates human carcinoma progression, correlating with known tumorigenic signatures of Shp2-dependent cancers. Immunohistochemistry was used to detect Siglec-XII expression on tissue microarrays. PC-3 prostate cancer cells were transfected with Siglec-XII and transcription of genes enriched with Siglec-XII was determined. Genomic SIGLEC12 status was determined for four different cancer cohorts. Finally, a dot blot analysis of human urinary epithelial cells was established to determine the Siglec-XII expressors versus non-expressors. Forced expression in a SIGLEC12 null carcinoma cell line enriched transcription of genes associated with cancer progression. While Siglec-XII was detected as expected in ~30%-40% of normal epithelia, ~80% of advanced carcinomas showed strong expression. Notably, >80% of late-stage colorectal cancers had a functional SIGLEC12 allele, correlating with overall increased mortality. Thus, advanced carcinomas are much more likely to occur in individuals whose genomes have an intact SIGLEC12 gene, likely because the encoded Siglec-XII protein recruits Shp2-related oncogenic pathways. The finding has prognostic, diagnostic, and therapeutic implications.

LCP1 is a prognostic biomarker correlated with immune infiltrates in gastric cancer

BACKGROUND

Previous studies have identified LCP1 as a diagnostic and prognostic marker in several cancers. However, the role of LCP1 in gastric cancer (GC) and its effect on tumor immune infiltration remain unclear.

OBJECTIVE

The aim was to explore the role of LCP1 in GC and its effect on tumor immune infiltration.

METHODS

We explored the expression of LCP1 relative to clinicopathology in GC patients by bioinformatics analysis and immunohistochemistry. Using cBioportal database, we analyzed the characteristic genetic variations of LCP1 in GC. In addition, we evaluated the correlation between LCP1 expression and tumor-infiltrating lymphocytes (TILs) using R software, TIMER and TISIDB databases. Finally, we analyzed the biological functions in which LCP1 may participate and the signaling pathways it may regulate.

RESULTS

Here, we showed that LCP1 expression is significantly correlated with tumor aggressiveness and poor prognosis in GC patients. Additionally, the results indicated that LCP1 was associated with TILs, including both immunosuppressive and immunosupportive cells, and was strongly correlated with various immune marker sets in GC. GSEA analysis demonstrated that LCP1 expression played an important role in lymphocyte formation and immune reaction.

CONCLUSIONS

LCP1 may be a potential prognostic biomarker for GC patients and a marker for tumor immunotherapy.

Exosomal Transfer of LCP1 Promotes Osteosarcoma Cell Tumorigenesis and Metastasis by Activating the JAK2/STAT3 Signaling Pathway

Increasing evidence indicates that lymphocyte cytosolic protein 1 (LCP1) overexpression contributes to tumor progression; however, its role in osteosarcoma (OS) remains unclear. We aimed to investigate the potential effect of LCP1 in OS and the underlying mechanisms. We first demonstrated that LCP1 is upregulated in OS cell lines and tissues. Then, we found that aberrant expression of LCP1 could induce the proliferation and metastasis of OS cells in vitro and in vivo by destabilizing neuregulin receptor degradation protein-1 (Nrdp1) and subsequently activating the JAK2/STAT3 signaling pathway. When coculturing OS cells with bone marrow-derived mesenchymal stem cells (BMSCs) in vitro, we validated that oncogenic LCP1 in OS was transferred from BMSCs via exosomes. Moreover, microRNA (miR)-135a-5p, a tumor suppressor, was found to interact upstream of LCP1 to counteract the pro-tumorigenesis effects of LCP1 in OS. In conclusion, BMSC-derived exosomal LCP1 promotes OS proliferation and metastasis via the JAK2/STAT3 pathway. Targeting the miR-135a-5p/LCP1 axis may have potential in treating OS.

The actin-bundling protein L-plastin-A double-edged sword: Beneficial for the immune response, maleficent in cancer

The dynamic organization of the actin cytoskeleton into bundles and networks is orchestrated by a large variety of actin-binding proteins. Among them, the actin-bundling protein L-plastin is normally expressed in hematopoietic cells, where it is involved in the immune response. However, L-plastin is also often ectopically expressed in malignant cancer cells of non-hematopoietic origin and is even considered as a marker for cancer progression. Post-translational modification modulates L-plastin activity. In particular, L-plastin Ser5 phosphorylation has been shown to be important for the immune response in leukocytes as well as for invasion and metastasis formation of carcinoma cells. This chapter discusses the physiological and pathological role of L-plastin with a special focus on the importance of L-plastin Ser5 phosphorylation for the protein functions. The potential use of Ser5 phosphorylated L-plastin as a biomarker and/or therapeutic target will be evoked.

SYT12 plays a critical role in oral cancer and may be a novel therapeutic target

Synaptotagmin12 (SYT12) has been well characterized as the regulator of transmitter release in the nervous system, however the relevance and molecular mechanisms of SYT12 in oral squamous cell carcinoma (OSCC) are not understood. In the current study, we investigated the expression of SYT12 and its molecular biological functions in OSCC by quantitative reverse transcriptase polymerase chain reaction, immunoblot analysis, and immunohistochemistry. SYT12 were up-regulated significantly in OSCC-derived cell lines and primary OSCC tissue compared with the normal counterparts (P<0.05) and the SYT12 expression levels were correlated significantly with clinical indicators, such as the primary tumoral size, lymph node metastasis, and TNM stage (P<0.05). SYT12 knockdown OSCC cells showed depressed cellular proliferation, migration, and invasion with cell cycle arrest at G1 phase. Surprisingly, we found increased calcium/calmodulin-dependent protein kinase 2 (CAMK2) inhibitor 1 (CAMK2N1) and decreased CAMK2-phosphorylation in the knockdown cells. Furthermore, treatment with L-3, 4-dihydroxyphenylalanine (L-dopa), a drug approved for Parkinson's disease, led to down-regulation of SYT12 and similar phenotypes to SYT12 knockdown cells. Taken together, we concluded that SYT12 plays a significant role in OSCC progression via CAMK2N1 and CAMK2, and that L-dopa would be a new drug for OSCC treatment through the SYT12 expression.

Combined Transcriptome and Proteome Analysis of Immortalized Human Keratinocytes Expressing Human Papillomavirus 16 (HPV16) Oncogenes Reveals Novel Key Factors and Networks in HPV-Induced Carcinogenesis

Human papillomavirus (HPV)-associated cancers still remain a big health problem, especially in developing countries, despite the availability of prophylactic vaccines. Although HPV oncogenes have been intensively investigated for decades, a study applying recent advances in RNA-Seq and quantitative proteomic approaches to a precancerous model system with well-defined HPV oncogene expression alongside HPV-negative parental cells has been missing until now. Here, combined omics analyses reveal global changes caused by the viral oncogenes in a less biased way and allow the identification of novel factors and key cellular networks potentially promoting malignant transformation. In addition, this system also provides a basis for mechanistic research on novel key factors regulated by HPV oncogenes, especially those that are confirmed in vivo in cervical cancer as well as in head and neck cancer patient samples from TCGA data sets.

Although the role of high-risk human papillomaviruses (hrHPVs) as etiological agents in cancer development has been intensively studied during the last decades, there is still the necessity of understanding the impact of the HPV E6 and E7 oncogenes on host cells, ultimately leading to malignant transformation. Here, we used newly established immortalized human keratinocytes with a well-defined HPV16 E6E7 expression cassette to get a more complete and less biased overview of global changes induced by HPV16 by employing transcriptome sequencing (RNA-Seq) and stable isotope labeling by amino acids in cell culture (SILAC). This is the first study combining transcriptome and proteome data to characterize the impact of HPV oncogenes in human keratinocytes in comparison with their virus-negative counterparts. To enhance the informative value and accuracy of the RNA-Seq data, four different bioinformatic workflows were used. We identified potential novel upstream regulators (e.g., CNOT7, SPDEF, MITF, and PAX5) controlling distinct clusters of genes within the HPV-host cell network as well as distinct factors (e.g., CPPED1, LCP1, and TAGLN) with essential functions in cancer. Validated results in this study were compared to data sets from The Cancer Genome Atlas (TCGA), demonstrating that several identified factors were also differentially expressed in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) and HPV-positive head and neck squamous cell carcinomas (HNSCs). This highly integrative approach allows the identification of novel HPV-induced cellular changes that are also reflected in cancer patients, providing a promising omics data set for future studies in both basic and translational research.

IMPORTANCE Human papillomavirus (HPV)-associated cancers still remain a big health problem, especially in developing countries, despite the availability of prophylactic vaccines. Although HPV oncogenes have been intensively investigated for decades, a study applying recent advances in RNA-Seq and quantitative proteomic approaches to a precancerous model system with well-defined HPV oncogene expression alongside HPV-negative parental cells has been missing until now. Here, combined omics analyses reveal global changes caused by the viral oncogenes in a less biased way and allow the identification of novel factors and key cellular networks potentially promoting malignant transformation. In addition, this system also provides a basis for mechanistic research on novel key factors regulated by HPV oncogenes, especially those that are confirmed in vivo in cervical cancer as well as in head and neck cancer patient samples from TCGA data sets.

Dual inhibition of ABCE1 and LCP1 by microRNA-96 results in an additive effect in breast cancer mouse model

MicroRNAs (miRNAs) are short non-coding RNAs that regulate the expression of target genes at the post-transcriptional level. Each miRNA can modulate multiple genes and, as a result, a single miRNA may have a profound effect on a specific biological pathway consisting of several of its target genes. Recent studies have indicated that specific miRNA signatures are correlated with tumor aggressiveness and clinical outcome in breast cancer. We previously demonstrated that miR-96 has a suppressive effect on breast cancer aggressiveness and that this effect was mediated by ABCE1 gene regulation. In this study we investigated whether other miR-96 regulated genes can enhance ABCE1’s anti-cancer effects. We identified one such gene – LCP1 – and proved its negative effect on breast cancer progression. Interestingly, dual inhibition of ABCE1 and LCP1 resulted in an additive effect on cancer cell migration, invasion, and proliferation. Furthermore, in vivo analysis of dual ABCE1 and LCP1 knockdown resulted in significant tumor growth inhibition, decreased metastatic activity, and contributed to survival compared to either gene, separately. This indicates that the combined downregulation of two miR-96 gene targets has an additive effect on reducing cancer aggressiveness. Overall, our work supports seeking more than one target in miRNA-based studies in order to enhance functional effects and better characterize the miRNA wide-spread activity.

Characterization of the EF-Hand Calcium-Binding Domains of Human Plastins

The three human plastins (L-plastin, T-plastin, and I-plastin) are important regulatory Ca²⁺-binding proteins that belong to the family of actin-binding proteins. Plastins are involved in the regulation of the actin cytoskeleton as well as the cross-linking of actin filaments. In addition to four calponin-homology (CH) domains, all three plastins contain two N-terminal EF-hand Ca²⁺-binding motifs which together are homologous to a single lobe of the well-known calcium-regulatory protein calmodulin. This part of the protein allows for the regulation of the actin bundling activity in response to elevated calcium levels. In this protocol, we describe the purification of the EF-hand headpiece domains of all three plastins, as well as SPR studies, ITC studies, and NMR interaction studies with different peptides and calcium. In combination, these three experimental techniques provide detailed insights into a novel regulatory mechanism, involving the linker region between the EF-hand domain and the first CH domain of the plastins.

Exosomal Release of L-Plastin by Breast Cancer Cells Facilitates Metastatic Bone Osteolysis

Bone metastasis from breast and prostate carcinomas is facilitated by activation of bone-resorbing osteoclasts. Using proteomics approaches, we have identified peroxiredoxin-4 (PRDX4) as a cancer-secreted mediator of osteoclastogenesis. We now report characterization of L-plastin in the conditioned media (CM) of MDA-MB-231 human breast cancer cells using immunoblotting and mass spectrometry. The osteoclastogenic potential of MDA-MB-231 CM with siRNA-silenced L-plastin was significantly reduced. L-plastin was detected in cancer-derived exosomes, and inhibition of exosomal release significantly decreased the osteoclastogenic capacity of MDA-MB-231 CM. When added to osteoclast precursors primed with RANKL for 2 days, recombinant L-plastin induced calcium/NFATc1-mediated osteoclastogenesis to the levels similar to continuous treatment with RANKL. Using shRNA, we generated MDA-MB-231 cells lacking L-plastin, PRDX4, or both and injected these cell populations intratibially in CD-1 immunodeficient mice. Micro-CT and histomorphometric analysis demonstrated a complete loss of osteolysis when MDA-MB-231 cells lacking both L-plastin and PRDX4 were injected. A meta-analysis established an increase in L-plastin and PRDX4 mRNA expression in numerous human cancers, including breast and prostate carcinomas. This study demonstrates that secreted L-plastin and PRDX4 mediate osteoclast activation by human breast cancer cells.

Increased expression of tripartite motif (TRIM) like 2 promotes tumoral growth in human oral cancer

Tripartite motif family-like 2 (TRIML2), a member of the TRIM proteins family, is closely related to Alzheimer's disease, however, no studies of TRIML2 have been published in the cancer research literature. In the current study, we investigated the expression level of TRIML2 and its molecular mechanisms in human oral squamous cell carcinoma (OSCC); reverse transcriptase-quantitative polymerase chain reaction, immunoblot analysis, and immunohistochemistry showed that TRIML2 is up-regulated significantly in OSCCs in vitro and in vivo. TRIML2 knockdown OSCC cells showed decreased cellular proliferation by cell-cycle arrest at G1 phase that resulted from down-regulation of CDK4, CDK6, and cyclin D1 and up-regulation of p21^Cip1 and p27^Kip1. Surprisingly, resveratrol, a polyphenol, led to not only down-regulation of TRIML2 but also cell-cycle arrest at G1 phase similar to TRIML2 knockdown experiments. Taken together, we concluded that TRIML2 might play a significant role in tumoral growth and that resveratrol may be a new drug for treating OSCC by interfering with TRIML2 function.

Enoxacin and bis-enoxacin stimulate 4T1 murine breast cancer cells to release extracellular vesicles that inhibit osteoclastogenesis

Enoxacin and its bone-seeking bisphosphonate derivative, bis-enoxacin, have recently captured attention as potential therapeutic agents for the treatment of cancer and bone disease. No differences in growth or survival of 4T1 murine breast cancer cells were detected at a concentration of 50 µM of enoxacin or bis-enoxacin. Growth was perturbed at higher concentrations. Both 50 µM enoxacin and bis-enoxacin stimulated increases in the number of GW/Processing bodies, but there were minimal changes in microRNA levels. Extracellular vesicles (EVs) released from 4T1 cells treated with 50 µM enoxacin or 50 µM bis-enoxacin stimulated proliferation of RAW 264.7 cells, and both significantly inhibited osteoclastogenesis in calcitriol-stimulated mouse marrow. EVs from 4T1 cells treated with enoxacin and bis-enoxacin displayed small reductions in the amount of microRNA (miR)-146a-5p and let-7b-5p. In marked contrast, miR-214-3p, which has been shown to regulate bone remodeling, was increased 22-fold and 30-fold respectively. We conclude that enoxacin and bis-enoxacin trigger the release of EVs from 4T1 cancer cells that inhibit osteoclastogenesis.

Overexpression of Translocation Associated Membrane Protein 2 Leading to Cancer-Associated Matrix Metalloproteinase Activation as a Putative Metastatic Factor for Human Oral Cancer

Translocation associated membrane protein 2 (TRAM2) has been characterized as a component of the translocon that is a gated channel at the endoplasmic reticulum (ER) membrane. TRAM2 is expressed in a wide variety of human organs. To date, no information is available regarding TRAM2 function in the genesis of human cancer. The purpose of this study was to investigate the status of the TRAM2 gene in oral squamous cell carcinoma (OSCC) cells and clinical OSCC samples. Using real-time quantitative reverse transcriptase-polymerase chain reaction, Western blotting analysis, and immunohistochemistry, we detected accelerated TRAM2 mRNA and protein expression levels both in OSCC-derived cell lines and primary tumors. Moreover, TRAM2-positive OSCC tissues were correlated closely (P<0.05) with metastasis to regional lymph nodes and vascular invasiveness. Of note, knockdown of TRAM2 inhibited metastatic phenotypes, including siTRAM2 cellular migration, invasiveness, and transendothelial migration activities with a significant (P<0.05) decrease in protein kinase RNA(PKR) - like ER kinase (PERK) and matrix metalloproteinases (MMPs) (MT1-MMP, MMP2, and MMP9). Taken together, our results suggested that TRAM2 might play a pivotal role in OSCC cellular metastasis by controlling major MMPs. This molecule might be a putative therapeutic target for OSCC.

Critical role of deoxynucleotidyl transferase terminal interacting protein 1 in oral cancer

Deoxynucleotidyl transferase terminal interacting protein 1 (DNTTIP1) forms a complex with histone deacetylase (HDAC); however, the relevance of DNTTIP1 in cancer remains unknown. The aim of this study was to examine DNTTIP1 expression and its functional mechanisms in oral squamous cell carcinomas (OSCCs). DNTTIP1 expression was analyzed by quantitative reverse transcriptase-polymerase chain reaction, immunoblotting analysis, and immunohistochemistry. The expression of DNTTIP1 was upregulated significantly in vitro and in vivo, and in patients with OSCC in whom DNTTIP1 was overexpressed and the expression level was correlated significantly (P < 0.05) with tumoral growth. DNTTIP1 knockdown (siDNTTIP1) cells showed depressed cellular proliferation by cell-cycle arrest at the G1 phase with high acetylation of p53 and upregulation of p21^Cip1. Moreover, resveratrol, a HDAC inhibitor, controlled not only acetylated p53 status but also DNTTIP1 expression, leading to a similar phenotype of siDNTTIP1 cells. A marked (P < 0.05) reduction of tumoral growth in mouse xenograft models was observed with lower DNTTIP1 expression under the presence of this chemical reagent. Taken together, our results suggested that DNTTIP1-HDAC interaction promotes tumoral growth through deacetylation of p53 and that DNTTIP1 might be a critical therapeutic target in OSCCs.

Morphology and genomic hallmarks of breast tumours developed by ATM deleterious variant carriers

Background

The ataxia telangiectasia mutated (ATM) gene is a moderate-risk breast cancer susceptibility gene; germline loss-of-function variants are found in up to 3% of hereditary breast and ovarian cancer (HBOC) families who undergo genetic testing. So far, no clear histopathological and molecular features of breast tumours occurring in ATM deleterious variant carriers have been described, but identification of an ATM-associated tumour signature may help in patient management.

Methods

To characterise hallmarks of ATM-associated tumours, we performed systematic pathology review of tumours from 21 participants from ataxia-telangiectasia families and 18 participants from HBOC families, as well as copy number profiling on a subset of 23 tumours. Morphology of ATM-associated tumours was compared with that of 599 patients with no BRCA1 and BRCA2 mutations from a hospital-based series, as well as with data from The Cancer Genome Atlas. Absolute copy number and loss of heterozygosity (LOH) profiles were obtained from the OncoScan SNP array. In addition, we performed whole-genome sequencing on four tumours from ATM loss-of-function variant carriers with available frozen material.

Results

We found that ATM-associated tumours belong mostly to the luminal B subtype, are tetraploid and show LOH at the ATM locus at 11q22–23. Unlike tumours in which BRCA1 or BRCA2 is inactivated, tumours arising in ATM deleterious variant carriers are not associated with increased large-scale genomic instability as measured by the large-scale state transitions signature. Losses at 13q14.11-q14.3, 17p13.2-p12, 21p11.2-p11.1 and 22q11.23 were observed. Somatic alterations at these loci may therefore represent biomarkers for ATM testing and harbour driver mutations in potentially ‘druggable’ genes that would allow patients to be directed towards tailored therapeutic strategies.

Conclusions

Although ATM is involved in the DNA damage response, ATM-associated tumours are distinct from BRCA1-associated tumours in terms of morphological characteristics and genomic alterations, and they are also distinguishable from sporadic breast tumours, thus opening up the possibility to identify ATM variant carriers outside the ataxia-telangiectasia disorder and direct them towards effective cancer risk management and therapeutic strategies.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-0951-9) contains supplementary material, which is available to authorized users.

Diacylglycerol lipase alpha promotes tumorigenesis in oral cancer by cell-cycle progression

Diacylglycerol lipase alpha (DAGLA), which catalyzes the hydrolysis of diacylglycerol to 2-arachidonoylglycerol and free fatty acid, is required for axonal growth during the brain development and for retrograde synaptic signaling at mature synapses. So far, no information was found regarding the possible role of DAGLA in human tumorigenesis. Thus, the current study sought to clarify the contribution of DAGLA in oral squamous cell carcinomas (OSCCs) and assess the clinical possibilities for OSCC treatment. Using real-time quantitative reverse transcription-polymerase chain reaction, immunoblotting, and immunohistochemistry, we found a significant up-regulation of DAGLA in OSCCs compared with normal cells and tissues both at mRNA and protein expression levels. Knockdown models in OSCC-derived cell lines for DAGLA (siDAGLA) and treatment with a lipase inhibitor (orlistat) showed several depressed cellular functions, including cellular proliferation and migratory activities through cell-cycle arrest at G1 phase. Furthermore, we found that DAGLA-positive OSCC samples were correlated highly with the primary tumoral size. We concluded that DAGLA may be a key determinant in tumoral progression and might be a therapeutic target for OSCCs.

Targeted deletion of the zebrafish actin-bundling protein L-plastin (lcp1)

Regulation of the cytoskeleton is essential for cell migration in health and disease. Lymphocyte cytosolic protein 1 (lcp1, also called L-plastin) is a hematopoietic-specific actin-bundling protein that is highly conserved in zebrafish, mice and humans. In addition, L-plastin expression is documented as both a genetic marker and a cellular mechanism contributing to the invasiveness of tumors and transformed cell lines. Despite L-plastin’s role in both immunity and cancer, in zebrafish there are no direct studies of its function, and no mutant, knockout or reporter lines available. Using CRISPR-Cas9 genome editing, we generated null alleles of zebrafish lcp1 and examined the phenotypes of these fish throughout the life cycle. Our editing strategy used gRNA to target the second exon of lcp1, producing F0 mosaic fish that were outcrossed to wild types to confirm germline transmission. F1 heterozygotes were then sequenced to identify three unique null alleles, here called ‘Charlie’, ‘Foxtrot’ and ‘Lima’. In silico, each allele truncates the endogenous protein to less than 5% normal size and removes both essential actin-binding domains (ABD1 and ABD2). Although none of the null lines express detectable LCP1 protein, homozygous mutant zebrafish (-/-) can develop and reproduce normally, a finding consistent with that of the L-plastin null mouse (LPL -/-). However, such mice do have a profound immune defect when challenged by lung bacteria. Interestingly, we observed reduced long-term survival of zebrafish lcp1 -/- homozygotes (~30% below the expected numbers) in all three of our knockout lines, with greatest mortality corresponding to the period (4–6 weeks post-fertilization) when the innate immune system is functional, but the adaptive immune system is not yet mature. This suggests that null zebrafish may have reduced capacity to combat opportunistic infections, which are more easily transmissible in the aquatic environment. Overall, our novel mutant lines establish a sound genetic model and an enhanced platform for further studies of L-plastin gene function in hematopoiesis and cancer.

Evaluation of tryptophan-aspartic acid repeat-containing protein 34 as a novel tumor-suppressor molecule in human oral cancer

Tryptophan-aspartic acid (WD) repeat-containing protein 34 (WDR34), one of the WDR protein superfamilies with five WD40 domains, inhibits a transforming growth factor-beta (TGF-β) activated kinase 1 (TAK1)-associated NF-κB activation pathway. Nevertheless, little is known about the roles of WDR34 in cancer. The current study sought to elucidate the clinical relevance of WDRsfb34 in oral squamous cell carcinoma (OSCC). We found WDR34 down-regulation in OSCCs compared with normal control tissues using real-time quantitative reverse transcription-polymerase chain reaction, immunoblotting, and immunohistochemistry. Models of overexpression of WDR34 (oeWDR34) showed depressed cellular growth through cell-cycle arrest at the G1 phase. To investigate the inhibitory function of WDR34, we challenged oeWDR34 cells with interleukin (IL)-1, a ligand for activation of the TAK1-NF-κB pathway and assessed the expression of a target gene of the pathway. oeWDR34 strongly inhibited IL-6 expression, which is closely related to tumoral growth, compared with control cells, suggesting that WDR34 would be a critical molecule for control of tumoral progression. In addition to the in vitro experiments, WDR34 negativity was correlated with tumoral growth of OSCCs. Our findings suggested that WDR34 inhibits OSCC progression and might be a potential tumor-suppressor molecule in OSCCs.