LIM Kinases in Osteosarcoma Development

LIM kinase 2 activates cardiac fibroblasts and exacerbates postinfarction left ventricular remodeling via crosstalk between the canonical and non-canonical Wnt pathways

Ischemic heart failure rates rise despite decreased acute myocardial infarction (MI) mortality. Excessive myofibroblast activation post-MI leads to adverse remodeling. LIM kinases (LIMK1 and LIMK2) regulate cytoskeleton homeostasis and are pro-fibrotic markers in atrial fibrillation. However, their roles and mechanisms in postinfarction fibrosis and ventricular remodeling remain unclear. This study found that the expression of LIMKs elevated in the border zone (BZ) in mice MI models. LIMK1/2 double knockout (DKO) restrained pathological remodeling and reduced mortality by suppressing myofibroblast activation. By using adeno-associated virus (AAV) with a periostin promoter to overexpress LIMK1 or LIMK2, this study found that myofibroblast-specific LIMK2 overexpression diminished these effects in DKO mice, while LIMK1 did not. LIMK2 kinase activity was critical for myofibroblast proliferation by using AAV overexpressing mutant LIMK2 lack of kinase activity. According to phosphoproteome analysis, functional rescue experiments, co-immunoprecipitation, and protein-protein docking, LIMK2 led to the phosphorylation of β-catenin at Ser 552. LIMK2 nuclear translocation also played a role in myofibroblast proliferation after MI with the help of AAV overexpressing mutant LIMK2 without nuclear location signal. Chromatin immunoprecipitation sequencing identified that LIMK2 bound to Lrp6 promoter region in TGF-β treated cardiac fibroblasts, positively regulating Wnt signaling via Wnt receptor internalization. This study demonstrated that LIMK2 promoted myofibroblast proliferation and adverse cardiac remodeling after MI, by enhancing phospho-β-catenin (Ser552) and Lrp6 signaling. This suggested that LIMK2 could be a target for the treatment of postinfarction injury.

PDE1B, a potential biomarker associated with tumor microenvironment and clinical prognostic significance in osteosarcoma

PDE1B had been found to be involved in various diseases, including tumors and non-tumors. However, little was known about the definite role of PDE1B in osteosarcoma. Therefore, we mined public data on osteosarcoma to reveal the prognostic values and immunological roles of the PDE1B gene. Three osteosarcoma-related datasets from online websites were utilized for further data analysis. R 4.3.2 software was utilized to conduct difference analysis, prognostic analysis, gene set enrichment analysis (GSEA), nomogram construction, and immunological evaluations, respectively. Experimental verification of the PDE1B gene in osteosarcoma was conducted by qRT-PCR and western blot, based on the manufacturer's instructions. The PDE1B gene was discovered to be lowly expressed in osteosarcoma, and its low expression was associated with poor OS (all P < 0.05). Experimental verifications by qRT-PCR and western blot results remained consistent (all P < 0.05). Univariate and multivariate Cox regression analyses indicated that the PDE1B gene had independent abilities in predicting OS in the TARGET osteosarcoma dataset (both P < 0.05). GSEA revealed that PDE1B was markedly linked to the calcium, cell cycle, chemokine, JAK STAT, and VEGF pathways. Moreover, PDE1B was found to be markedly associated with immunity (all P < 0.05), and the TIDE algorithm further shed light on that patients with high-PDE1B expression would have a better immune response to immunotherapies than those with low-PDE1B expression, suggesting that the PDE1B gene could prevent immune escape from osteosarcoma. The PDE1B gene was found to be a tumor suppressor gene in osteosarcoma, and its high expression was related to a better OS prognosis, suppressing immune escape from osteosarcoma.

SLC9A2, suppressing by the transcription suppressor ETS1, restrains growth and invasion of osteosarcoma via inhibition of aerobic glycolysis

Recent studies have shown that Solute Carrier Family 9 Member A2 (SLC9A2) could serve as a biomarker for cancer. However, its mechanism of action in osteosarcoma (OS) was still unclear. In this study, the data sets GSE154530 and GSE99671 were downloaded from the Gene Expression Omnibus (GEO) database, and 31 differentially expressed genes (DEGs) related to methylation were screened by bioinformatics analysis tools. Subsequently, SLC9A2 was screened as a candidate gene from DEGs, which was significantly downregulated in OS. CCK-8, transwell, western blotting and Seahorse XFe24 Cell Metabolic Analyzer assays demonstrated that overexpression of SLC9A2 could constrain OS cell proliferation, invasion, and aerobic glycolysis. Dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP) assays indicated ETS proto-oncogene 1 (ETS1) was a transcription suppressor of SLC9A2, and overexpression of ETS1 could promote methylation levels in specific regions of the SLC9A2 promoter. ETS1 could promote the proliferation, invasion, and aerobic glycolysis ability of OS cells, as well as tumor growth in vivo by inhibiting the expression of SLC9A2. In addition, SLC9A2, suppressing by ETS1, restrains growth and invasion of OS via inhibition of aerobic glycolysis. Thus, SLC9A2 can function as a key inhibitory factor in the aerobic glycolysis to inhibit proliferation and invasion of OS. This indicated that SLC9A2 has a potential targeted therapeutic effect on OS.

LIM Kinases: From Molecular to Pathological Features

LIM kinases (LIMKs), LIMK1 and LIMK2, are atypical kinases, as they are the only two members of the LIM kinase family harbouring two LIM domains at their N-terminus and a kinase domain at their C-terminus [...].

miR-137-LAPTM4B regulates cytoskeleton organization and cancer metastasis via the RhoA-LIMK-Cofilin pathway in osteosarcoma

Osteosarcoma (OS) is a rare malignant bone tumor but is one leading cause of cancer mortality in childhood and adolescence. Cancer metastasis accounts for the primary reason for treatment failure in OS patients. The dynamic organization of the cytoskeleton is fundamental for cell motility, migration, and cancer metastasis. Lysosome Associated Protein Transmembrane 4B (LAPTM4B) is an oncogene participating in various biological progress central to cancer biogenesis. However, the potential roles of LAPTM4B in OS and the related mechanisms remain unknown. Here, we established the elevated LAPTM4B expression in OS, and it is essential in regulating stress fiber organization through RhoA-LIMK-cofilin signaling pathway. In terms of mechanism, our data revealed that LAPTM4B promotes RhoA protein stability by suppressing the ubiquitin-mediated proteasome degradation pathway. Moreover, our data show that miR-137, rather than gene copy number and methylation status, contributes to the upregulation of LAPTM4B in OS. We report that miR-137 is capable of regulating stress fiber arrangement, OS cell migration, and metastasis via targeting LAPTM4B. Combining results from cells, patients' tissue samples, the animal model, and cancer databases, this study further suggests that the miR-137-LAPTM4B axis represents a clinically relevant pathway in OS progression and a viable target for novel therapeutics.

Diallyl disulfide downregulating RhoGDI2 induces differentiation and inhibit invasion via the Rac1/Pak1/LIMK1 pathway in human leukemia HL-60 cells

Leukemia is a type of disease in which hematopoietic stem cells proliferate clonally at the genetic level. We discovered previously by high-resolution mass spectrometry that diallyl disulfide (DADS), which is one of the effective ingredients of garlic, reduces the performance of RhoGDI2 from APL HL-60 cells. Although RhoGDI2 is oversubscribed in several cancer categories, the effect of RhoGDI2 in HL-60 cells has remained unexplained. We aimed to investigate the influence of RhoGDI2 on DADS-induced differentiation of HL-60 cells to elucidate the association among the effect of inhibition or over-expression of RhoGDI2 with HL-60 cell polarization, migration and invasion, which is important for establishing a novel generation of inducers to elicit leukemia cell polarization. Co-transfection with RhoGDI2-targeted miRNAs apparently decreases the malignant biological behavior of cells and upregulates cytopenias in DADS-treated HL-60 cell lines, which increases CD11b and decreases CD33 and mRNA levels of Rac1, PAK1 and LIMK1. Meanwhile, we generated HL-60 cell lines with high-expressing RhoGDI2. The proliferation, migration and invasion capacity of such cells were significantly increased by the treated with DADS, while the reduction capacity of the cells was decreased. There was a reduction in CD11b and an increase in CD33 production, as well as an increase in the mRNA levels of Rac1, PAK1 and LIMK1. It also confirmed that inhibition of RhoGDI2 attenuates the EMT cascade via the Rac1/Pak1/LIMK1 pathway, thereby inhibiting the malignant biological behavior of HL-60 cells. Thus, we considered that inhibition of RhoGDI2 expression might be a new therapeutic direction for the treatment of human promyelocytic leukemia. The anti-cancer property of DADS against HL-60 leukemia cells might be regulated by RhoGDI2 through the Rac1-Pak1-LIMK1 pathway, which provides new evidence for DADS as a clinical anti-cancer medicine.

LIM Kinases, LIMK1 and LIMK2, Are Crucial Node Actors of the Cell Fate: Molecular to Pathological Features

LIM kinase 1 (LIMK1) and LIM kinase 2 (LIMK2) are serine/threonine and tyrosine kinases and the only two members of the LIM kinase family. They play a crucial role in the regulation of cytoskeleton dynamics by controlling actin filaments and microtubule turnover, especially through the phosphorylation of cofilin, an actin depolymerising factor. Thus, they are involved in many biological processes, such as cell cycle, cell migration, and neuronal differentiation. Consequently, they are also part of numerous pathological mechanisms, especially in cancer, where their involvement has been reported for a few years and has led to the development of a wide range of inhibitors. LIMK1 and LIMK2 are known to be part of the Rho family GTPase signal transduction pathways, but many more partners have been discovered over the decades, and both LIMKs are suspected to be part of an extended and various range of regulation pathways. In this review, we propose to consider the different molecular mechanisms involving LIM kinases and their associated signalling pathways, and to offer a better understanding of their variety of actions within the physiology and physiopathology of the cell.

Screening crucial lncRNAs and genes in osteoarthritis by integrated analysis

BACKGROUND

Osteoarthritis (OA) is one of the most frequent chronic diseases with high morbidity worldwide, marked by degradation of the cartilage and bone, joint instability, stiffness, joint space stenosis and subchondral sclerosis. Due to the elusive mechanism of osteoarthritis (OA), we aimed to identify potential markers for OA and explore the molecular mechanisms underlying OA.

METHODS

Expression profiles data of OA were collected from the Gene Expression Omnibus database to identify differentially expressed mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs) in OA. Functional annotation and protein-protein interaction (PPI) networks were performed. Then, nearby DEmRNAs of DElncRNAs was obtained. Moreover, GO and KEGG pathway enrichment analysis of nearby DEmRNAs of DElncRNAs was performed. Finally, expression validation of selected mRNAs and lncRNAs was performed by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

In total, 2080 DEmRNAs and 664 DElncRNAs were determined in OA. PI3K-Akt signaling pathway, Endocytosis and Rap1 signaling pathway were significantly enriched KEGG pathways in OA. YWHAB, HSPA8, NEDD4L and SH3KBP1 were four hub proteins in PPI network. The AC093484.4/TRPV2 interact pair may be involved in the occurrence and development of OA.

CONCLUSION

Our study identified several DEmRNAs and DElncRNAs associated with OA. The molecular characters could provide more information for further study on OA.

Bioinformatics Analysis Reveals an Association between Autophagy, Prognosis, Tumor Microenvironment, and Immunotherapy in Osteosarcoma

Autophagy is a catabolic pathway involved in the regulation of bone homeostasis. We explore clinical correlation of autophagy-related key molecules to establish risk signature for predicting the prognosis, tumor microenvironment (TME), and immunotherapy response of osteosarcoma. Single cell RNA sequencing data from GSE162454 dataset distinguished malignant cells from normal cells in osteosarcoma. Autophagy-related genes (ARGs) were extracted from the established risk signature of the Molecular Signatures Database of Gene Set Enrichment Analysis (GSEA) by univariate Cox and least absolute shrinkage and selection operator (LASSO) Cox regression analysis. Overall survival (OS), TME score, abundance of infiltrating immune cells, and response to immune-checkpoint blockade (ICB) treatment in patients with different risks were compared based on risk score. Nine ARGs were identified and risk signature was constructed. In all osteosarcoma datasets, the OS was significantly longer in the high-risk patients than low-risk onset. Risk signature significantly stratified clinical outcomes, including OS, metastatic status, and survival status. Risk signature was an independent variable for predicting osteosarcoma OS and showed high accuracy. A nomogram based on risk signature and metastases was developed. The calibration curve confirmed the consistency in 1-year, 3-year, and 5-year predicted OS and the actual OS. The risk score was related to 6 kinds of T cells and macrophages, myeloid-derived suppressor cell, natural killer cell, immune score, and stromal score in TME. The risk signature helped in predicting patients' response to anti-PD1/anti-PD-L1 treatment. The ARGs-led risk signature has important value for survival prediction, risk stratification, tumor microenvironment, and immune response evaluation of osteosarcoma.