Comprehensive bioinformatics analysis and experimental validation: An anoikis-related gene prognostic model for targeted drug development in head and neck squamous cell carcinoma.

We analyzed RNA-sequencing (RNA-seq) and clinical data from head and neck squamous cell carcinoma (HNSCC) patients in The Cancer Genome Atlas (TCGA) Genomic Data Commons (GDC) portal to investigate the prognostic value of anoikis-related genes (ARGs) in HNSCC and develop new targeted drugs. Differentially expressed ARGs were screened using bioinformatics methods; subsequently, a prognostic model including three ARGs (CDKN2A, BIRC5, and PLAU) was constructed. Our results showed that the model-based risk score was a good prognostic indicator, and the potential of the three ARGs in HNSCC prognosis was validated by the TISCH database, the model's accuracy was validated in two independent cohorts of the Gene Expression Omnibus database. Immune correlation analysis and half-maximal inhibitory concentration were also performed to reveal the different landscapes of TIME between risk groups and to predict immuno- and chemo-therapeutic responses. Potential small-molecule drugs for HNSCC were subsequently predicted using the L1000FWD database. Finally, in vitro experiments were used to verify the database findings. The relative ARG mRNA expression levels in HNSCC and surrounding normal tissues remained consistent with the model results. BIRC5 knockdown inhibited anoikis resistance in WSU-HN6 and CAL-27 cells. Molecular docking, real-time PCR, cell counting kit-8 (CCK-8), plate clone, and flow cytometry analyses showed that small-molecule drugs predicted by the database may target the ARGs in the prognostic model, inhibit HNSCC cells survival rate, and promote anoikis in vitro. Therefore, we constructed a new ARG model for HNSCC patients that can predict prognosis and immune activity and identify a potential small-molecule drug for HNSCC, paving the way for clinically targeting anoikis in HNSCC.

NFATC1 and NFATC2 expression patterns in human osteochondromas.

Background: Our previous study in genetic mouse models found that NFATc1 and NFATc2 suppress osteochondroma formation from entheseal progenitors. However, it remains unclear whether NFAT signaling is also involved in human osteochondromagenesis. As the first step in addressing this question, the current study aimed to determine the expression patterns of NFATC1 and NFATC2 in human osteochondroma samples. Methods: Immunohistochemistry (IHC) was used to examine and analyze NFATC1 and NFATC2 expression in human osteochondroma samples. The human periosteum was used to map the expression of NFATC1 under physiological conditions by IHC. Furthermore, human periosteal progenitors were isolated and identified from the periosteal tissues of bone fracture healing patients. The expression of NFATC1 in human periosteal progenitors was characterized by Western blotting compared to human bone marrow stromal cells (BMSC). Results: The IHC results showed that the expression of NFATC1 was undetectable in most human osteochondromas cells, and only a small proportion of osteochondroma cells, especially clonally grown chondrocytes, showed positive staining of NFATC1. NFATC2 expression was also undetectable in most chondrocytes in human osteochondromas. The mouse and human periosteum showed a comparable ratio of NFATC1 positive cells (9.56 ± 0.80% vs 11.04 ± 2.05%, P = 0.3101). Furthermore, Western blotting analysis revealed that NFATC1 expression was highly enriched in human periosteal progenitors compared to BMSC. Conclusions: NFATC1 and NFATC2 are undetectable in most human osteochondroma chondrocytes. The expression pattern of NFATC1 in human osteochondromas and the normal periosteum suggests that NFAT signaling could be suppressed during human osteochondromagenesis.

NFATc1 marks articular cartilage progenitors and negatively determines articular chondrocyte differentiation.

The origin and differentiation mechanism of articular chondrocytes remain poorly understood. Broadly, the difference in developmental mechanisms of articular and growth-plate cartilage is still less elucidated. Here, we identified that the nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) is a crucial regulator of articular, but not growth-plate, chondrocyte differentiation during development. At the early stage of mouse knee development (embryonic day 13.5), NFATc1-expressing cells were mainly located in the flanking region of the joint interzone. With development, NFATc1-expressing cells generated almost all articular chondrocytes but not chondrocytes in limb growth-plate primordium. NFATc1-expressing cells displayed prominent capacities for colony formation and multipotent differentiation. Transcriptome analyses revealed a set of characteristic genes in NFATc1-enriched articular cartilage progenitors. Strikingly, the expression of NFATc1 was diminished with articular chondrocyte differentiation, and suppressing NFATc1 expression in articular cartilage progenitors was sufficient to induce spontaneous chondrogenesis while overexpressing NFATc1 suppresses chondrogenesis. Mechanistically, NFATc1 negatively regulated the transcriptional activity of the Col2a1 gene. Thus, our results reveal that NFATc1 characterizes articular, but not growth-plate, cartilage progenitors during development and negatively determines articular chondrocyte differentiation at least partly through regulating COL2A1 gene transcription.

Within the body are about 300 joints connecting bones together. Many factors ­ including trauma, inflammation, aging, and genetic changes ­ can affect the cushion tissue covering the end of the bones in these joints known as articular cartilage. This can lead to diseases such as osteoarthritis which cause chronic pain, and in some cases disability. To treat such conditions, it is essential to know how cells in the articular cartilage are formed during development. In the embryo, most cells come from groups of progenitor cells that are programmed to produce specific types of tissue. But which progenitor cells are responsible for producing the main cells in articular cartilage, chondrocytes, and the mechanisms that govern this transformation are poorly understood. In 2016, a group of researchers found that the gene for the protein NFATc1, which is important for building bone, is also expressed in a group of progenitor cells at the site where ligaments insert into bone in mice. Inactivation of NFATc1 in these progenitor cells has also been shown to cause abnormal cartilage to form, a condition termed osteochondromas. Building on this work, Zhang, Wang et al. ­ including some of the researchers involved in the 2016 study ­ set out to find whether NFATc1 is also involved in the normal development of articular chondrocytes. To investigate, the team used genetically modified mice in which any cells with NFATc1 also had a green fluorescent protein, and tracked these cells and their progeny over the course of joint development. This led them to discover a group of NFATc1-containing progenitor cells that gave rise to almost all articular chondrocytes in the knee joint. Further experiments revealed that when NFATc1 was removed, this made the progenitors become articular chondrocytes very quickly. In contrast, when the cells had excess amounts of the protein, the formation of articular chondrocytes was significantly reduced. This suggests that the level of NFATc1 governs when progenitors develop into articular chondrocytes. These findings have provided a way to track the progenitors of articular chondrocytes throughout development and study how articular cartilage is formed. In the future, this work could help researchers develop treatment strategies for osteoarthritis and other cartilage-based diseases. However, before this can happen, further work is needed to confirm that the effects observed in this study also relate to humans.

Potential prognostic value of a eight ferroptosis-related lncRNAs model and the correlative immune activity in oral squamous cell carcinoma.

BACKGROUND: To investigate the prognostic value of ferroptosis-related long noncoding RNAs (lncRNAs) in oral squamous cell carcinoma (OSCC) and to construct a prognostic risk and immune activity model. METHODS: We obtained clinical and RNA-seq information on OSCC patient data in The Cancer Genome Atlas (TCGA) Genome Data Sharing (GDC) portal. Through a combination of a differential analysis, Pearson correlation analysis and Cox regression analysis, ferroptosis-related lncRNAs were identified, and a prognostic model was established based on these ferroptosis-related lncRNAs. The accuracy of the model was evaluated via analyses based on survival curves, receiver operating characteristic (ROC) curves, and clinical decision curve analysis (DCA). Univariate Cox and multivariate Cox regression analyses were performed to evaluate independent prognostic factors. Then, the infiltration and functional enrichment of immune cells in high- and low-risk groups were compared. Finally, certain small-molecule drugs that potentially target OSCC were predicted via use of the L1000FWD database. RESULTS: The prognostic model included 8 ferroptosis-related lncRNAs (FIRRE, LINC01305, AC099850.3, AL512274.1, AC090246.1, MIAT, AC079921.2 and LINC00524). The area under the ROC curve (AUC) was 0.726. The DCA revealed that the risk score based on the prognostic model was a better prognostic indicator than other clinical indicators. The multivariate Cox regression analysis showed that the risk score was an independent prognostic factor for OSCC. There were differences in immune cell infiltration, immune functions, m6A-related gene expression levels, and signal pathway enrichment between the high- and low-risk groups. Subsequently, several small-molecule drugs were predicted for use against differentially expressed ferroptosis-related genes in OSCC. CONCLUSIONS: We constructed a new prognostic model of OSCC based on ferroptosis-related lncRNAs. The model is valuable for prognostic prediction and immune evaluation, laying a foundation for the study of ferroptosis-related lncRNAs in OSCC.

A RUNX2 stabilization pathway mediates physiologic and pathologic bone formation.

The osteoblast differentiation capacity of skeletal stem cells (SSCs) must be tightly regulated, as inadequate bone formation results in low bone mass and skeletal fragility, and over-exuberant osteogenesis results in heterotopic ossification (HO) of soft tissues. RUNX2 is essential for tuning this balance, but the mechanisms of posttranslational control of RUNX2 remain to be fully elucidated. Here, we identify that a CK2/HAUSP pathway is a key regulator of RUNX2 stability, as Casein kinase 2 (CK2) phosphorylates RUNX2, recruiting the deubiquitinase herpesvirus-associated ubiquitin-specific protease (HAUSP), which stabilizes RUNX2 by diverting it away from ubiquitin-dependent proteasomal degradation. This pathway is important for both the commitment of SSCs to osteoprogenitors and their subsequent maturation. This CK2/HAUSP/RUNX2 pathway is also necessary for HO, as its inhibition blocked HO in multiple models. Collectively, active deubiquitination of RUNX2 is required for bone formation and this CK2/HAUSP deubiquitination pathway offers therapeutic opportunities for disorders of inappropriate mineralization.

The secreted protein WNT5A regulates condylar chondrocyte proliferation, hypertrophy and migration.

OBJECTIVE: Our previous study showed that WNT5A, a member of the noncanonical WNT pathway, is involved in interleukin-1beta induced matrix metalloproteinase expression in temporomandibular joint (TMJ) condylar chondrocytes. The purpose of this study is to further explore the roles of WNT5A in cartilage biology of the TMJ. METHODS: An early TMJ osteoarthritis-like rat model was constructed by a mechanical method (steady mouth-opening). The gene and protein levels of WNT5A during the condylar cartilage changes were measured. Effects of WNT5A on chondrocyte proliferation, hypertrophy and migration were analyzed after WNT5A gain or loss of function in vitro. A c-Jun N-terminal kinase (JNK) inhibitor SP600125 was used to evaluate the involvement of JNK pathway in these effects of WNT5A. The expression and transcription activity of cell cycle regulators c-MYC and Cyclin D1 were examined to determine the mechanism behind WNT5A regulation of chondrocyte proliferation. RESULTS: WNT5A was significantly upregulated in the condylar cartilage of rats in the early TMJ osteoarthritis-like model. Activating WNT5A facilitated condylar chondrocyte proliferation, hypertrophy and migration. Conversely, inhibiting WNT5A activity in chondrocytes decreased their proliferation, hypertrophy and migration. Blockage of the JNK pathway by its inhibitor, SP600125, impaired these effects of WNT5A on chondrocytes. WNT5A regulated both the expression and transcriptional activity of c-MYC and Cyclin D1 in chondrocytes, both of which were upregulated in condylar cartilage of the rat early TMJ osteoarthritis. CONCLUSION: WNT5A regulates condylar chondrocyte proliferation, hypertrophy and migration. These findings provide new insights into the role of WNT5A signaling in TMJ cartilage biology and its potential in future therapy for TMJ degenerative diseases.

RANK-Independent Osteoclast Formation and Bone Erosion in Inflammatory Arthritis.

OBJECTIVE: Proinflammatory molecules promote osteoclast-mediated bone erosion by up-regulating local RANKL production. However, recent evidence suggests that combinations of cytokines, such as tumor necrosis factor (TNF) plus interleukin-6 (IL-6), induce RANKL-independent osteoclastogenesis. The purpose of this study was to better understand TNF/IL-6-induced osteoclast formation and to determine whether RANK is absolutely required for osteoclastogenesis and bone erosion in murine inflammatory arthritis. METHODS: Myeloid precursors from wild-type (WT) mice or mice with either germline or conditional deletion of Rank, Nfatc1, Dap12, or Fcrg were treated with either RANKL or TNF plus IL-6. Osteoprotegerin, anti-IL-6 receptor (anti-IL-6R), and hydroxyurea were used to block RANKL, the IL-6R, and cell proliferation, respectively. Clinical scoring, histologic assessment, micro-computed tomography, and quantitative polymerase chain reaction (qPCR) were used to evaluate K/BxN serum-transfer arthritis in WT and RANK-deleted mice. Loss of Rank was verified by qPCR and by osteoclast cultures. RESULTS: TNF/IL-6 generated osteoclasts in vitro that resorbed mineralized tissue through a pathway dependent on IL-6R, NFATc1, DNAX-activation protein 12, and cell proliferation, but independent of RANKL or RANK. Bone erosion and osteoclast formation were reduced, but not absent, in arthritic mice with inducible deficiency of RANK. TNF/IL-6, but not RANKL, induced osteoclast formation in bone marrow and synovial cultures from animals deficient in Rank. Multiple IL-6 family members (IL-6, leukemia inhibitory factor, oncostatin M) were up-regulated in the synovium of arthritic mice. CONCLUSION: The persistence of bone erosion and synovial osteoclasts in Rank-deficient mice, and the ability of TNF/IL-6 to induce osteoclastogenesis, suggest that more than one cytokine pathway exists to generate these bone-resorbing cells in inflamed joints.

Sex-Specific Protection of Osteoarthritis by Deleting Cartilage Acid Protein 1.

Cartilage acidic protein 1 (CRTAC1) was recently identified as an elevated protein in the synovial fluid of patients with osteoarthritis (OA) by a proteomic analysis. This gene is also upregulated in both human and mouse OA by transcriptomic analysis. The objective of this study was to characterize the expression and function of CRTAC1 in OA. Here, we first confirm the increase of CRTAC1 in cartilage biopsies from OA patients undergoing joint replacement by real-time PCR and immunohistochemistry. Furthermore, we report that proinflammatory cytokines interleukin-1beta and tumor necrosis factor alpha upregulate CRTAC1 expression in primary human articular chondrocytes and synovial fibroblasts. Genetic deletion of Crtac1 in mice significantly inhibited cartilage degradation, osteophyte formation and gait abnormalities of post-traumatic OA in female, but not male, animals undergoing the destabilization of medial meniscus (DMM) surgery. Taken together, CRTAC1 is upregulated in the osteoarthritic joint and directly induced in chondrocytes and synovial fibroblasts by pro-inflammatory cytokines. This molecule is necessary for the progression of OA in female mice after DMM surgery and thus represents a potential therapy for this prevalent disease, especially for women who demonstrate higher rates and more severe OA.

NFAT restricts osteochondroma formation from entheseal progenitors.

Osteochondromas are common benign osteocartilaginous tumors in children and adolescents characterized by cartilage-capped bony projections on the surface of bones. These tumors often cause pain, deformity, fracture, and musculoskeletal dysfunction, and they occasionally undergo malignant transformation. The pathogenesis of osteochondromas remains poorly understood. Here, we demonstrate that nuclear factor of activated T cells c1 and c2 (NFATc1 and NFATc2) suppress osteochondromagenesis through individual and combinatorial mechanisms. In mice, conditional deletion of NFATc1 in mesenchymal limb progenitors, Scleraxis-expressing (Scx-expressing) tendoligamentous cells, or postnatally in Aggrecan-expressing cells resulted in osteochondroma formation at entheses, the insertion sites of ligaments and tendons onto bone. Combinatorial deletion of NFATc1 and NFATc2 gave rise to larger and more numerous osteochondromas in inverse proportion to gene dosage. A population of entheseal NFATc1- and Aggrecan-expressing cells was identified as the osteochondroma precursor, previously believed to be growth plate derived or perichondrium derived. Mechanistically, we show that NFATc1 restricts the proliferation and chondrogenesis of osteochondroma precursors. In contrast, NFATc2 preferentially inhibits chondrocyte hypertrophy and osteogenesis. Together, our findings identify and characterize a mechanism of osteochondroma formation and suggest that regulating NFAT activity is a new therapeutic approach for skeletal diseases characterized by defective or exaggerated osteochondral growth.

Requirement of the NF-κB pathway for induction of Wnt-5A by interleukin-1ß in condylar chondrocytes of the temporomandibular joint: functional crosstalk between the Wnt-5A and NF-κB signaling pathways.

OBJECTIVE: We have previously reported that interleukin-1ß (IL-1ß) up-regulates the expression of Wnt-5A and the activation of Wnt-5A signaling induces matrix metalloproteinase (MMP) through the c-Jun N-terminal kinase pathway in condylar chondrocytes (CCs) of the temporomandibular joint (TMJ). These results suggest that Wnt-5A could play an essential role in IL-1ß-mediated cartilage destruction. The objective of this study was to investigate the molecular mechanism underlying IL-1ß-induced up-regulation of Wnt-5A in TMJ CCs. METHODS: Primary CCs, limb chondrocytes (LCs) and SW1353 human chondrosarcoma cells were treated with IL-1ß in the presence or absent of BAY 11-7082 (an inhibitor of IκBα-phosphorylation). Then, expression of Wnt-5A was estimated by real-time reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunocytofluorescence. Transient transfection of p65 expression vector and chromatin immunoprecipitation (ChIP) assay was performed to define the effect of p65 on Wnt-5A expression. RESULTS: IL-1ß up-regulated Wnt-5A expression at both the RNA and protein levels in articular chondrocytes. The inhibitor of IκBα-phosphorylation, BAY 11-7082, blocked the induction of Wnt-5A by IL-1ß in a dose-dependent manner. Moreover, experiments with overexpression of p65 and ChIP established that induction of Wnt-5A by IL-1ß is mediated through the NF-κB pathway, especially the p65 subunit. CONCLUSION: These results clarify the molecular mechanism underlying up-regulation of Wnt-5A by IL-1ß in chondrocytes, suggesting an important functional crosstalk between Wnt-5A and NF-κB signaling pathways. This finding provides new insights into the involvement of Wnt signaling in the cartilage destruction caused by arthritis.

Role of Wnt-5A in interleukin-1beta-induced matrix metalloproteinase expression in rabbit temporomandibular joint condylar chondrocytes.

OBJECTIVE: To determine the possible involvement and regulatory mechanisms of Wnt-5A signaling in interleukin-1beta (IL-1beta)-induced increase in matrix metalloproteinase 1 (MMP-1), MMP-3, MMP-9, and MMP-13 expression in temporomandibular joint (TMJ) condylar chondrocytes. METHODS: Primary rabbit condylar chondrocytes were treated with IL-1beta, purified Wnt-5A protein, or both and transfected with Wnt-5A expression vector. Expression of Wnt-5A, MMP-1, MMP-3, MMP-9, MMP-13, and type II collagen, as well as cell morphologic changes, were examined. To explore the mechanisms of action of Wnt-5A, the accumulation and nuclear translocation of beta-catenin, the transcription activity of the beta-catenin-Tcf/Lef complex, phosphorylated JNK, phosphorylated ERK, and phosphorylated p38 were analyzed. SP600125, a JNK inhibitor, was used to investigate the role of the JNK pathway in Wnt-5A induction of MMP-1, MMP-3, MMP-9, and MMP-13. RESULTS: Treatment of rabbit condylar chondrocytes with IL-1beta up-regulated Wnt-5A expression. Purified Wnt-5A protein and transfection with Wnt-5A expression vector promoted the expression of MMP-1, MMP-3, MMP-9, and MMP-13. Wnt-5A did not cause accumulation and nuclear translocation of beta-catenin or activation of the beta-catenin-Tcf/Lef transcription complex. Instead, Wnt-5A activated JNK, and an inhibitor of JNK blocked the Wnt-5A-induced up-regulated expression of MMPs. CONCLUSION: These findings indicate that IL-1beta up-regulates Wnt-5A, and the activation of Wnt-5A signaling induces the expression of MMP-1, MMP-3, MMP-9, and MMP-13 via the JNK signaling pathway in rabbit TMJ condylar chondrocytes. Blockage of JNK signaling impairs the Wnt-5A-induced up-regulation of MMPs. Thus, Wnt-5A may be associated with cartilage destruction by promoting the expression of MMPs.