Paving the path for invasion: The polyedric role of LASP1 in cancer

m6A-modified circ_0124554 promotes colorectal cancer progression and radioresistance through the miR-1184/LASP1 pathway

BACKGROUND

Circular RNAs (circRNAs) are believed to regulate the progression of various cancers including colorectal cancer (CRC). However, the role and mechanism of circ_0124554 in regulating the sensitivity of CRC to radiation remain unknown.

METHODS

The RNA levels of circ_0124554, LIM and SH3 protein 1 (LASP1), and methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3) were detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. Cell proliferation, apoptosis, migration, and invasion were investigated by 5-Ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry analysis, and transwell assay, respectively. The sensitivity of CRC cells to radiation was analyzed by cell colony formation assay. Xenograft mouse model assay was conducted to disclose the role of circ_0001023 in the sensitivity of tumors to radiation in vivo. The binding relationships among circ_0124554, miR-1184 and LASP1 were confirmed by a dual-luciferase reporter assay. m6A RNA immunoprecipitation assay was performed to identify the association of METTL3 with circ_0124554.

RESULTS

Circ_0124554 expression was upregulated in CRC tissues and cells in comparison with normal colorectal tissues and cells. Circ_0124554 knockdown inhibited proliferation, migration and invasion and promoted apoptosis and radiosensitivity of CRC cells. Moreover, circ_0124554 depletion inhibited tumor formation and improved radiosensitivity in vivo. MiR-1184 was identified as a target miRNA of circ_0124554 and targeted LASP1. Additionally, LASP1 overexpression rescued circ_0124554 knockdown-mediated effects in CRC cells. METTL3 mediated m6A methylation of circ_0124554. Further, circ_0124554 overexpression attenuated METTL3 depletion-induced effects in CRC cells.

CONCLUSION

m6A-modified circ_0124554 promoted CRC progression and radioresistance by inducing LASP1 expression through interaction with miR-1184.

LASP1, CERS6, and Actin Form a Ternary Complex That Promotes Cancer Cell Migration

CERS6 is associated with metastasis and poor prognosis in non-small cell lung cancer (NSCLC) patients through d18:1/C16:0 ceramide (C16 ceramide)-mediated cell migration, though the detailed mechanism has not been elucidated. In the present study, examinations including co-immunoprecipitation, liquid chromatography, and tandem mass spectrometry analysis were performed to identify a novel binding partner of CERS6. Among the examined candidates, LASP1 was a top-ranked binding partner, with the LIM domain possibly required for direct interaction. In accord with those findings, CERS6 and LASP1 were found to co-localize on lamellipodia in several lung cancer cell lines. Furthermore, silencing of CERS6 and/or LASP1 significantly suppressed cell migration and lamellipodia formation, whereas ectopic addition of C16 ceramide partially rescued those phenotypes. Both LASP1 and CERS6 showed co-immunoprecipitation with actin, with those interactions markedly reduced when the LASP1-CERS6 complex was abolished. Based on these findings, it is proposed that LASP1-CERS6 interaction promotes cancer cell migration.

Hepatitis B virus X protein increases LASP1 SUMOylation to stabilize HER2 and facilitate hepatocarcinogenesis

The hepatitis B virus (HBV) X protein (HBX), a viral macromolecule, plays a vital role in the development of HBV-related hepatocellular carcinoma (HCC). Increased expression of HER2 is linked to HBV infection, and HBX is responsible for HER2 upregulation in HCC. Nevertheless, the underlying molecular mechanisms are not yet fully understood. In the study, we discovered that HBX promoted HER2 expression to facilitate the sensitization of the insulin signaling pathway and enhance the growth and migration of HCC cells. Mechanistically, the viral protein enhanced the stability of HER2 by preventing its ubiquitination-mediated proteasomal degradation through LASP1, which could bind to HER2. Furthermore, increased SUMOylation of LASP1 contributed to the upregulation of HER2 and the interaction of LASP1 with HER2. In addition, RANBP2 and RANGAP1 were found to interact with LASP1 and promote SUMOylation of LASP1 to upregulate HER2 expression in HBX-associated hepatoma cells. In summary, our work provides a novel insight into hepatocarcinogenesis mediated by HBX and estimates the detailed mechanisms related to the increase in HER2 regulated by the viral protein, which might help provide a theoretical basis for identifying novel targets for HBV-positive HCC treatment.

Protein Kinase A in cellular migration—Niche signaling of a ubiquitous kinase

Cell migration requires establishment and maintenance of directional polarity, which in turn requires spatial heterogeneity in the regulation of protrusion, retraction, and adhesion. Thus, the signaling proteins that regulate these various structural processes must also be distinctly regulated in subcellular space. Protein Kinase A (PKA) is a ubiquitous serine/threonine kinase involved in innumerable cellular processes. In the context of cell migration, it has a paradoxical role in that global inhibition or activation of PKA inhibits migration. It follows, then, that the subcellular regulation of PKA is key to bringing its proper permissive and restrictive functions to the correct parts of the cell. Proper subcellular regulation of PKA controls not only when and where it is active but also specifies the targets for that activity, allowing the cell to use a single, promiscuous kinase to exert distinct functions within different subcellular niches to facilitate cell movement. In this way, understanding PKA signaling in migration is a study in context and in the elegant coordination of distinct functions of a single protein in a complex cellular process.

LASP1 Induces Epithelial-Mesenchymal Transition in Lung Cancer through the TGF-β1/Smad/Snail Pathway

Background. LIM and SH3 domain protein 1 (LASP1), highly expressed in a variety of tumors, is considered as a novel tumor metastasis biomarker. However, it is unknown which signaling pathway works and how the signal transduces into cell nucleus to drive tumor progression by LASP1. The aim of this study is to explore the essential role of LASP1 in TGF-β1-induced epithelial-mesenchymal transition (EMT) in lung cancer cells. Methods. The gene and protein levels of LASP-1 were successfully silenced or overexpressed by LASP-1 shRNA lentivirus or pcDNA in TGF-β1-treated lung cancer cell lines, respectively. Then, the cells were developed EMT by TGF-β1. The cell abilities of invasion, migration, and proliferation were measured using Transwell invasion assay, wound healing assay, and MTT assay, respectively. Western blotting was used to observe the protein levels of EMT-associated molecules, including N-cadherin, vimentin, and E-cadherin, and the key molecules in the TGF-β1/Smad/Snail signaling pathway, including pSmad2 and Smad2, pSmad3 and Smad3, and Smad7 in cell lysates, as well as Snail1, pSmad2, and pSmad3 in the nucleus. Results. TGF-β1 induced higher LASP1 expression. LASP1 silence and overexpression blunted or promoted cell invasion, migration, and proliferation upon TGF-β1 stimulation. LASP1 also regulated the expression of vimentin, N-cadherin, and E-cadherin in TGF-β1-treated cells. Activity of key Smad proteins (pSmad2 and pSmad3) and protein level of Smad7 were markedly regulated through LASP1. Furthermore, LASP1 affected the nuclear localizations of pSmad2, pSmad3, and Snail1. Conclusion. This study reveals that LASP1 regulates the TGF-β1/Smad/Snail signaling pathway and EMT markers and features, involving in key signal molecules and their nuclear levels. Therefore, LASP1 might be a drug target in lung cancer.

HSP90-dependent PUS7 overexpression facilitates the metastasis of colorectal cancer cells by regulating LASP1 abundance

BACKGROUND

Pseudouridine synthase (PUS) 7 is a member of the PUS family that catalyses pseudouridine formation. It has been shown to be involved in intellectual development and haematological malignancies. Nevertheless, the role and the underlying molecular mechanisms of PUS7 in solid tumours, such as colorectal cancer (CRC), remain unexplored. This study elucidated, for the first time, the role of PUS7 in CRC cell metastasis and the underlying mechanisms.

METHODS

We conducted immunohistochemistry, qPCR, and western blotting to quantify the expression of PUS7 in CRC tissues as well as cell lines. Besides, diverse in vivo and in vitro functional tests were employed to establish the function of PUS7 in CRC. RNA-seq and proteome profiling analysis were also applied to identify the targets of PUS7. PUS7-interacting proteins were further uncovered using immunoprecipitation and mass spectrometry.

RESULTS

Overexpression of PUS7 was observed in CRC tissues and was linked to advanced clinical stages and shorter overall survival. PUS7 silencing effectively repressed CRC cell metastasis, while its upregulation promoted metastasis, independently of the PUS7 catalytic activity. LASP1 was identified as a downstream effector of PUS7. Forced LASP1 expression abolished the metastasis suppression triggered by PUS7 silencing. Furthermore, HSP90 was identified as a client protein of PUS7, associated with the increased PUS7 abundance in CRC. NMS-E973, a specific HSP90 inhibitor, also showed higher anti-metastatic activity when combined with PUS7 repression. Importantly, in line with these results, in human CRC tissues, the expression of PUS7 was positively linked to the expression of HSP90 and LASP1, and patients co-expressing HSP90/PUS7/LASP1 showed a worse prognosis.

CONCLUSIONS

The HSP90-dependent PUS7 upregulation promotes CRC cell metastasis via the regulation of LASP1. Thus, targeting the HSP90/PUS7/LASP1 axis may be a novel approach for the treatment of CRC.

miRNAs Involved in Esophageal Carcinogenesis and miRNA-Related Therapeutic Perspectives in Esophageal Carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs that play a pivotal role in many aspects of cell biology, including cancer development. Within esophageal cancer, miRNAs have been proved to be involved in all phases of carcinogenesis, from initiation to metastatic spread. Several miRNAs have been found to be dysregulated in esophageal premalignant lesions, namely Barrett’s esophagus, Barrett’s dysplasia, and squamous dysplasia. Furthermore, numerous studies have investigated the alteration in the expression levels of many oncomiRNAs and tumor suppressor miRNAs in esophageal squamous cell carcinoma and esophageal adenocarcinoma, thus proving how miRNAs are able modulate crucial regulatory pathways of cancer development. Considering these findings, miRNAs may have a role not only as a diagnostic and prognostic tool, but also as predictive biomarker of response to anti-cancer therapies and as potential therapeutic targets. This review aims to summarize several studies on the matter, focusing on the possible diagnostic–therapeutic implications.

Endometrial stromal cell proteomic analysis reveals LIM and SH3 protein 1 (LASP1) plays important roles in the progression of adenomyosis

Adenomyosis is one of the most common gynecological disorders that the molecular events underlying its pathogenesis remain not fully understood. Prior studies have shown that endometrial stromal cells (ESCs) played crucial roles in the pathogenesis of adenomyosis. In this study, we utilized two-dimensional gel electrophoresis combined with protein identification by mass spectrometry (2D/MS) proteomics analysis to compare the differential protein expression profile between the paired eutopic and ectopic ESCs (EuESCs and EcESCs) in adenomyosis, and a total of 32 significantly altered protein spots were identified. Among which, the expression of LIM and SH3 protein 1 (LASP1) was increased significantly in EcESCs compared to EuESCs. Immunohistochemical assay showed that LASP1 was overexpressed in the stromal cells of ectopic endometriums compared to eutopic endometriums; further functional analyses revealed that LASP1 overexpression could enhance cell proliferation, migration and invasion of EcESCs. Furthermore, we also showed that the dysregulated expression of LASP1 in EcESCs was associated with DNA hypermethylation in the promoter region of the LASP1 gene. However, the detailed molecular mechanisms of enhancing cell proliferation, invasion and migration caused by upregulated LASP1 in adenomyosis needs further study. For the first time, our data suggested that LASP1 plays important roles in the pathogenesis of adenomyosis, and could serve as a prognostic biomarker of adenomyosis.

p21-activated kinase 4 promotes the progression of esophageal squamous cell carcinoma by targeting LASP1

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors of the digestive tract in humans. Several studies have indicated that PAK4 is associated with the risk of ESCC and may be a potential druggable kinase for ESCC treatment. However, the underlying mechanism remains largely unknown. The aim of our study is to identify the functional role of PAK4 in ESCC. To determine the expression of PAK4 in ESCC, Western blot analysis and immunohistochemistry were performed, and the results showed that PAK4 is significantly upregulated in ESCC tissues and cell lines compared with normal controls and normal esophageal epithelial cell line. To further investigate the role of PAK4 in ESCC, cell viability assays, anchorage-independent cell growth assays, wound healing assays, cellular invasion assays, in vivo xenograft mouse models, and metastasis assays were conducted, and the results showed that PAK4 can significantly facilitate ESCC proliferation and metastasis in vitro and in vivo. To determine the potential target of PAK4 in ESCC progression, a pull-down assay was performed, and the results showed that LASP1 may be a potential target of PAK4. An immunoprecipitation assay and confocal microscopy analysis confirmed that PAK4 can bind to and colocalize with LASP1 in vitro and in cells. Notably, rescue experiments further illustrated the mechanistic network of PAK4/LASP1. Our research reveals the oncogenic roles of PAK4 in ESCC and preliminarily elucidates the mechanistic network of PAK4/LASP1 in ESCC.

LIM and SH3 protein 1 (LASP-1): A novel link between the slit membrane and actin cytoskeleton dynamics in podocytes

The foot processes of podocytes exhibit a dynamic actin cytoskeleton, which maintains their complex cell structure and antagonizes the elastic forces of the glomerular capillary. Interdigitating secondary foot processes form a highly selective filter for proteins in the kidney, the slit membrane. Knockdown of slit membrane components such as Nephrin or Neph1 and cytoskeletal adaptor proteins such as CD2AP in mice leads to breakdown of the filtration barrier with foot process effacement, proteinuria, and early death of the mice. Less is known about the crosstalk between the slit membrane-associated proteins and cytoskeletal components inside the podocyte foot processes. Our study shows that LASP-1, an actin-binding protein, is highly expressed in podocytes. Electron microscopy studies demonstrate that LASP-1 is found at the slit membrane suggesting a role in anchoring slit membrane components to the actin cytoskeleton. Live cell imaging experiments with transfected podocytes reveal that LASP-1 is either part of a highly dynamic granular complex or a static, actin cytoskeleton-bound protein. We identify CD2AP as a novel LASP-1 binding partner that regulates its association with the actin cytoskeleton. Activation of the renin-angiotensin-aldosterone system, which is crucial for podocyte function, leads to phosphorylation and altered localization of LASP-1. In vivo studies using the Drosophila nephrocyte model indicate that Lasp is necessary for the slit membrane integrity and functional filtration.

miR-133 inhibits proliferation and promotes apoptosis by targeting LASP1 in lupus nephritis

Lupus nephritis (LN) is a chronic autoimmune disease. Recently, microRNA (miR)-133 has been demonstrated to play an important role in renal cell carcinoma. Our current study was designed to test the role of miR-133 and its potential target in LN. First, significant correlation of LASP1 and miR-133 levels was observed in the human LN tissue. Modification of miR-133 level in the human mesangial cells (HMCs) by either overexpression or knockdown demonstrated a suppressive role of miR-133 in cell proliferation and an inductive role in cell apoptosis. Modification of LASP1 level in the HMCs demonstrated the opposing effects of LASP1 to miR-133 on proliferation and apoptosis. In addition, luciferase assay showed miR-133 directly regulates LASP1 expression through its binding site in the 3'UTR of LASP1. At last, our data showed that the changes in properties, such as suppression in proliferation and induction in apoptosis, induced by overexpression of miR-133 were restored by additional expression of LASP1. In summary, our obtained data demonstrated that miR-133 suppresses proliferation and promotes apoptosis through its binding with LASP1 in human mesangial cells. This study revealed a new mechanism involving the interaction of miR-133 and LASP1 in the pathogenesis of LN.

Knockout of LASP1 in CXCR4 expressing CML cells promotes cell persistence, proliferation and TKI resistance

Chronic myeloid leukaemia (CML) is a clonal myeloproliferative stem cell disorder characterized by the constitutively active BCR-ABL tyrosine kinase. The LIM and SH3 domain protein 1 (LASP1) has recently been identified as a novel BCR-ABL substrate and is associated with proliferation, migration, tumorigenesis and chemoresistance in several cancers. Furthermore, LASP1 was shown to bind to the chemokine receptor 4 (CXCR4), thought to be involved in mechanisms of relapse. In order to identify potential LASP1-mediated pathways and related factors that may help to further eradicate minimal residual disease (MRD), the effect of LASP1 on processes involved in progression and maintenance of CML was investigated. The present data indicate that not only overexpression of CXCR4, but also knockout of LASP1 contributes to proliferation, reduced apoptosis and migration as well as increased adhesive potential of K562 CML cells. Furthermore, LASP1 depletion in K562 CML cells leads to decreased cytokine release and reduced NK cell-mediated cytotoxicity towards CML cells. Taken together, these results indicate that in CML, reduced levels of LASP1 alone and in combination with high CXCR4 expression may contribute to TKI resistance.

LASP1 promotes proliferation, metastasis, invasion in head and neck squamous cell carcinoma and through direct interaction with HSPA1A

LIM and SH3 protein 1 (LASP1) is a specific focal adhesion protein that promotes metastasis in a variety of tumours. However, its role in head and neck squamous cell carcinoma (HNSCC) has not been fully validated. The purpose of this study was to analyse the interaction of LASP1 and its binding partner in HNSCC. The expression of LASP1 and HSPA1A in HNSCC was analysed by real-time PCR and Western blot. The effects of LASP1 on the biology behaviour of HNSCC cell lines were observed in vivo and in vitro. Co-immunoprecipitation analysis was performed to confirm the interaction between LASP1 and HSPA1A. LASP1 was highly expressed in HNSCC and associated with poor prognosis for patients. LASP1 also promoted cell proliferation, colony formation, invasion and cell cycle G2/M phase transition. Heat shock protein family A member 1A (HSPA1A) is identified as a chaperone protein of LASP1 and co-localized in the cytoplasm. HSPA1A positively regulates the interaction of LASP1 with P-AKT and enhances the malignant behaviour of HNSCC cells. LASP1 and HSPA1A are both up-regulated in HNSCC, and directly binds to each other. Double inhibition of LASP1 and HSPA1A expression may be an effective method for the treatment of HNSCC.

Proteomics Study of Mesenchymal Stem Cell-Like Cells Isolated from Cerebrospinal Fluid of Patients with Meningioma

Background:

Cerebrospinal fluid (CSF) contains pro-growth factors that can affect proliferation, migration and differentiation of Mesenchymal Stem Cells (MSCs).

Objective:

This study aimed to isolate MSC like cells from CSF of patients with meningioma and psudotumorcerebri (PTC) and identify differentially expressed proteins in these cells.

Methods:

Five patients with newly diagnosed intracranial meningioma and five patients with PTC were recruited in this comparative proteomics study. MSCs were isolated from CSF and validated by mesenchyml and non-mesenchyml fluorochrome antibodies, and flow cytometer analysis. Two- Dimensional Gel Electrophoresis (2-DE) coupled with Mass Spectrometry (MS) was performed to identify differentially expressed proteins.

Results:

Microscopic views of the isolated cells as well as flow cytometer analysis were found to be compatible with MSC-like cells. Eight distinct protein spots were differentially and reproducibly expressed among the stained gels of two studied groups. The identified proteins were Phosphoglycerate Mutase 1 (PGAM1), LIM and SH3 domain protein (LASP1), peroxiredoxin-6 (PRDX-6), type I cytoskeletal 9 (KRT9), Superoxide Dismutase (SOD), endoplasmin, Stathmin 1 (STMN1), and glutathione S-transferase (GST).

Conclusion:

This study provides new insights into the plausible role of CSF derived MSCs in cancer progression, and reveals a promising therapeutic opportunity for targeting of MSC proteins in patients with meningioma.

LIM and SH3 protein 1 regulates cell growth and chemosensitivity of human glioblastoma via the PI3K/AKT pathway

Background

LIM and SH3 protein 1 (LASP1) is upregulated in several types of human cancer and implicated in cancer progression. However, the expression and intrinsic function of LASP1 in glioblastoma (GBM) remains unclear.

Method

Oncomine and The Cancer Genome Atlas (TCGA) database was analyzed for the expression and clinical significance of LASP1 in GBM. LASP1 mRNA and protein level were measured by qRT-PCR and western blotting. The effect of LASP1 on GBM proliferation was examined by MTT assay and colony formation assay, the effect of LASP1 on sensitivity of Temozolomide was measured by flow cytometry and subcutaneous tumor model. The association between LASP1 and PI3K/AKT signaling was assessed by western blotting.

Results

Oncomine GBM dataset analysis indicated LASP1 is significantly upregulated in GBM tissues compared to normal tissues. GBM dataset from The Cancer Genome Atlas (TCGA) revealed that high LASP1 expression is related to poor overall survival. LASP1 mRNA and protein in clinical specimens and tumor cell lines are frequently overexpressed. LASP1 knockdown dramatically suppressed U87 and U251 cell proliferation. Silencing LASP1 potentiated cell chemosensitivity to temozolomide in vitro, LASP1 knockdown inhibited tumor growth and enhanced the therapeutic effect of temozolomide in vivo. TCGA dataset analysis indicated LASP1 was correlated with PI3K/AKT signaling pathway, and LASP1 deletion inhibited this pathway. Combination treatment with PI3K/AKT pathway inhibitor LY294002 dramatically accelerated the suppression effect of temozolomide.

Conclusion

LASP1 may function as an oncogene in GBM and regulate cell proliferation and chemosensitivity in a PI3K/AKT-dependent mechanism. Thus, the LASP1/PI3K/AKT axis is a promising target and therapeutic strategy for GBM treatment.

HER2 is not a cancer subtype but rather a pan-cancer event and is highly enriched in AR-driven breast tumors

BACKGROUND

Approximately one in five breast cancers are driven by amplification and overexpression of the human epidermal growth factor receptor 2 (HER2) receptor kinase, and HER2-enriched (HER2E) is one of four major transcriptional subtypes of breast cancer. We set out to understand the genomics of HER2 amplification independent of subtype, and the underlying drivers and biology of HER2E tumors.

METHODS

We investigated published genomic data from 3155 breast tumors and 5391 non-breast tumors.

RESULTS

HER2 amplification is a distinct driver event seen in all breast cancer subtypes, rather than a subtype marker, with major characteristics restricted to amplification and overexpression of HER2 and neighboring genes. The HER2E subtype has a distinctive transcriptional landscape independent of HER2A that reflects androgen receptor signaling as replacement for estrogen receptor (ER)-driven tumorigenesis. HER2 amplification is also an event in 1.8% of non-breast tumors.

CONCLUSIONS

These discoveries reveal therapeutic opportunities for combining anti-HER2 therapy with anti-androgen agents in breast cancer, and highlight the potential for broader therapeutic use of HER2 inhibitors.

A seven-gene prognostic signature for rapid determination of head and neck squamous cell carcinoma survival

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer and displays divergent clinical outcomes. Prognostic biomarkers might improve risk stratification and survival prediction. We aimed to investigate the prognostic genes associated with overall survival. A two-step gene selection method was used to develop a seven-gene-based prognostic model based on the training set collected from The Cancer Genome Atlas (TCGA). In addition, the prognostic model was validated in an independent testing set from Gene Expression Omnibus (GEO). The score based on the model successfully distinguished HNSCC survival into high-risk and low-risk groups in the training set (HR, 2.79; 95% CI, 1.98–3.92; P=4.05×10⁻⁹) and the testing set (HR, 2.05; 95% CI, 1.35–3.11; P=7.98×10⁻⁴). In addition, the score could significantly predict 5-year survival by ROC curves (AUCs for training set, 0.73; testing set, 0.66). Combining risk scores with clinical characteristics improved the AUCs beyond using clinical characteristics alone (training set, from 0.57 to 0.75; testing set, from 0.63 to 0.72). A subgroup sensitivity analysis with HPV status and tumor sites revealed that the risk score was significant in all subgroups except oral cavity tumors of the testing set. Furthermore, HPV-positive status improves survival in oropharyngeal HNSCC but not non-oropharyngeal HNSCC. In conclusion, the seven-gene prognostic signature is a reliable and practical prognostic tool for HNSCC. This approach can add prognostic value to clinical characteristics and provides a new possibility for individualized treatment.