Lumican mediates HTB94 chondrosarcoma cell growth via an IGF‑IR/Erk1/2 axis

Chondrosarcoma is a malignant bone tumor characterized by the production of a modified cartilage-type extracellular matrix (ECM). In the present study, the expression levels of the small leucine-rich proteoglycans (SLRPs), decorin, biglycan and lumican, were examined in the HTB94 human chondrosarcoma cell line. HTB94 cells were found to express and secrete the 3 SLRP members. RT-qPCR and western blot analysis demonstrated that lumican was the most abundantly secreted SLRP, whereas decorin and biglycan expression levels were low. The utilization of short interfering RNA specific for the decorin, biglycan, and lumican genes resulted in the efficient downregulation of the respective mRNA levels (P≤0.001). The growth of the HTB94 cells was stimulated by lumican (P≤0.001), whereas their migration and adhesion were not affected (P=NS). By contrast, these cellular functions were not sensitive to a decrease in low endogenous levels of decorin and biglycan. Lumicandeficiency significantly inhibited both basal and insulin-like growth factor I (IGF-I)-induced HTB94 cell growth (P≤0.001 andP≤0.01, respectively). These effects were executed through the insulin-like growth factor I receptor (IGF-IR), whose activation was markedly attenuated (P≤0.01) in lumican-deficient HTB94 cells. The downregulation of lumican induced the substantial inhibition of extracellular regulated kinase (ERK1/2) activation (P≤ 0.01), indicating that ERK1/2 is a necessary component of lumican/IGF-IR-mediated HTB94 cell proliferation. Moreover, the lumican-deficient cells exhibit increased mRNA levels of p53 (P≤0.05), suggesting that lumican facilitates HTB94 cell growth through an IGF-IR/ERK1/2/p53 signaling cascade. On the whole, the findings of the present study demonstrate that endogenous lumican is a novel regulator of HTB94 cell growth.

Contact allergen (PPD and DNCB)-induced keratinocyte sensitization is partly mediated through a low molecular weight hyaluronan (LMWHA)/TLR4/NF-κB signaling axis

Allergic contact dermatitis (ACD) is caused by topical exposure to chemical allergens. Keratinocytes play a key role in innate immunity, as well as in ACD progression. The transmembrane Toll-like receptor 4 (TLR4), strongly implicated in skin inflammation, has the ability to bind Damage Associated Molecular Patterns (DAMPs), like Low Molecular Weight Hyaluronan (LMWHA). Previously, we had determined that p-phenylenediamine (PPD) and 2,4-dinitrochlorobenzene (DNCB) modulate keratinocyte HA deposition in a manner correlated to their sensitization. In the present study, we aimed to investigate putative co-operation of HA and TLR4 in the process of PPD and DNCB-induced keratinocyte activation. Contact sensitizers were shown to significantly increase the expression of Hyaluronan Synthases (HAS) and TLR4 in NCTC2544 human keratinocytes, as demonstrated by western blot and Real-Time PCR. These data, in correlation to earlier shown enhanced HA degradation suggest that the contact sensitizers facilitate HA turnover of keratinocytes and increase the release of pro-inflammatory, LMWHA fragments. Treatment with exogenous LMWHA enhanced TLR4, HAS levels and Nuclear factor-kappa beta (NF-κΒ) activation. PPD, DNCB and LMWHA-effects were shown to be partly executed through TLR4 downstream signaling as shown by Real-Time, western blot, siRNA and confocal microscopy approaches. Specifically, PPD and DNCB stimulated the activation of the TLR4 downstream mediator NF-κB. Therefore, the shown upregulation of TLR4 expression is suggested to further facilitate the release of endogenous, bioactive HA fragments and sustain keratinocyte activation. In conclusion, keratinocyte contact allergen-dependent sensitization is partly mediated through a LMWHA/TLR4/ NF-κB signaling axis.

Biglycan Regulates MG63 Osteosarcoma Cell Growth Through a LPR6/β-Catenin/IGFR-IR Signaling Axis

Biglycan, a small leucine rich proteoglycan (SLRP), is an important participant in bone homeostasis and development as well as in bone pathology. In the present study biglycan was identified as a positive regulator of MG63 osteosarcoma cell growth (p ≤ 0.001). IGF-I was shown to increase biglycan expression (p ≤ 0.01), whereas biglycan-deficiency attenuated significantly both basal and IGF-I induced cell proliferation of MG63 cells (p ≤ 0.001; p ≤ 0.01, respectively). These effects were executed through the IGF-IR receptor whose activation was strongly attenuated (p ≤ 0.01) in biglycan-deficient MG63 cells. Biglycan, previously shown to regulate Wnt/β-catenin pathway, was demonstrated to induce a significant increase in β-catenin protein expression evident at cytoplasmic (p ≤ 0.01), membrane (p ≤ 0.01), and nucleus fractions in MG63 cells (p ≤ 0.05). As demonstrated by immunofluorescence, increase in β-catenin expression is attributed to co-localization of biglycan with the Wnt co-receptor low-density lipoprotein receptor-related protein 6 (LRP6) resulting in attenuated β-catenin degradation. Furthermore, applying anti-β-catenin and anti-pIGF-IR antibodies to MG-63 cells demonstrated a cytoplasmic and to the membrane interaction between these molecules that increased upon exogenous biglycan treatment. In parallel, the downregulation of biglycan significantly inhibited both basal and IGF-I-dependent ERK1/2 activation, (p ≤ 0.001). In summary, we report a novel mechanism where biglycan through a LRP6/β-catenin/IGF-IR signaling axis enhances osteosarcoma cell growth.

IGF-I regulates HT1080 fibrosarcoma cell migration through a syndecan-2/Erk/ezrin signaling axis

Fibrosarcoma is a tumor of mesenchymal origin, originating from fibroblasts. IGF-I is an anabolic growth factor which exhibits significant involvement in cancer progression. In this study, we investigated the possible participation of syndecan-2 (SDC-2), a cell membrane heparan sulfate (HS) proteoglycan on IGF-I dependent fibrosarcoma cell motility. Our results demonstrate that SDC-2-deficient HT1080 cells exhibit attenuated IGF-I-dependent chemotactic migration (p < 0.001). SDC-2 was found to co-localize to IGF-I receptor (IGF-IR) in a manner dependent on IGF-I activity (P ≤ 0.01). In parallel, the downregulation of SDC-2 significantly inhibited both basal and due to IGF-I action ERK1/2 activation, (p < 0.001). The phosphorylation levels of ezrin (Thr567), which is suggested to act as a signaling bridge between the cellular membrane receptors and actin cytoskeleton, were strongly enhanced by IGF-I at both 1h and 24h (p < 0.05; p < 0.01). The formation of an immunoprecipitative complex revealed an association between SDC2 and ezrin which was enhanced through IGF-I action (p < 0.05). Immunoflourescence demonstrated a co-localization of IGF-IR, SDC2 and ezrin upregulated by IGF-I action. IGF-I enhanced actin polymerization and ezrin/actin specific localization to cell membranes. Finally, treatment with IGF-I strongly increased SDC2 expression at both the mRNA and protein level (p < 0.001). Therefore, we propose a novel SDC2-dependent mechanism, where SDC2 is co-localized with IGF-IR and enhances its' IGFI-dependent downstream signaling. SDC2 mediates directly IGFI-induced ERK1/2 activation, it recruits ezrin, contributes to actin polymerization and ezrin/actin specific localization to cell membranes, ultimately facilitating the progression of IGFI-dependent fibrosarcoma cell migration.

Emerging roles of syndecan 2 in epithelial and mesenchymal cancer progression

Syndecan 2 (SDC2) belongs to a four-member family of evolutionary conserved small type I transmembrane proteoglycans consisting of a protein core to which glycosaminoglycan chains are covalently attached. SDC2 is a cell surface heparan sulfate proteoglycan, which is increasingly drawing attention for its distinct characteristics and its participation in numerous cell functions, including those related to carcinogenesis. Increasing evidence suggests that the role of SDC2 in cancer pathogenesis is dependent on cancer tissue origin rendering its use as a biomarker/therapeutic target feasible. This mini review discusses the mechanisms, through which SDC2, in a distinct manner, modulates complex signalling networks to affect cancer progression. © 2017 IUBMB Life, 69(11):824-833, 2017.

Cross-cultural translation and validation of the Greek version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in patients with total knee replacement

PURPOSE

Aim of this study is to assess the psychometric properties of the developed Greek version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in total knee replacement (TKR) patients.

METHODS

Psychometric properties of the Greek version of KOOS were evaluated according to the Consensus-based Standards Measurements Instruments (COSMIN) checklist. Patients' pre-operative clinical status and post-operative outcomes at two occasions (at discharge and 10-12 days post-operatively) were evaluated using the KOOS, KOS-ADL and SF-12 Health Survey.

RESULTS

A comprehensive Greek KOOS was piloted and well accepted by patients and therefore administered to 60 consecutive TKR patients (mean age 72.2 ± 7.2 years, 39 women). Excellent Internal consistency, good test-retest reliability of KOOS and KOOS 5 subdomains, respectively [ICC(2-1) 0.76, 95% CI = 0.235-0.902 and 0.89, 95% CI = 0.843-0.927] was yielded. A priori hypotheses for construct validity were confirmed with KOOS score and subdomains for pain, symptoms and Everyday Living function (ADL) correlating moderately with KOS-ADL. Responsiveness for KOOS subdomains of Pain and Symptoms yielded moderate effect size (ES = 0.4).

CONCLUSION

The Greek KOOS was found to be a practical and comprehensible self-reported measure for TKR patients with acceptable psychometric properties. It is therefore, recommendable for usage in future clinical trials and clinical practice. Implications for Rehabilitation The Greek version of KOOS is an essential assessment scale to evaluate not only acute injuries but also chronic knee associated conditions in a holistic perspective. The Greek KOOS has been found to be a practical and comprehensible self-reported measure for TKR patients with acceptable psychometric properties, recommendable for usage in future clinical trials and clinical practice. KOOS Greek version (downloadable at the official site http://www.koos.nu/koosgreek.pdf ) was used in the validity study.

Mechanoreceptors of the Posterior Cruciate Ligament

The mechanical role of the anterior and posterior cruciate ligaments in the passive and functional stability of the knee joint has been well documented. Both these knee joint ligaments contain Ruffini, Pacinian, Golgi and free nerve endings with different capabilities of providing the central nervous system with information regarding movement and position as well as chemical events. The posterior cruciate ligament provides 95% of the restraining force to a posterior tibial displacement, is significantly stronger than the other knee ligaments, and sensory nerve endings are located in the tibia and femoral bone insertions. This report aims to review the anatomy and physiology of the various mechanoreceptors of the posterior cruciate ligament, placing special emphasis on their role in knee joint stability. It concludes that the posterior crude ligament may not only serve as a ‘mechanical stabilizer’ of the knee joint, but also probably has an important ‘sensory function’ that should be taken into account when dealing with injuries to it.

Vertebral osteomyelitis, epidural and psoas abscess after epidural catheter use

We report on a patient who developed persistent low back pain, pyrexia and neurological deficit soon after she underwent a laparotomy under combined general and epidural anaesthesia. The diagnosis of lumbar vertebral osteomyelitis, discitis, epidural and psoas abscesses was made one month later when she was referred to our institution. The patient was successfully treated with posterior decompression, drainage of the epidural abscess and fusion in combination with percutaneous, computed tomography-guided needle aspiration of the psoas abscesses.

Revision arthroscopic partial meniscectomy of the knee. A retrospective review

The aim in this study was to find out if there were any revision operations in patients who underwent an arthroscopic partial meniscectomy and we attempted to identify the factor(s) that may be associated with the need for that revision. We reviewed 1,603 patients who underwent an arthroscopic partial meniscectomy, and 16 cases of revision were identified (rate 1%). Nine factors were analysed: age, sex, affected knee, affected meniscus, private or National Health Service (NHS) patient, symptoms prior to the most recent meniscectomy, type of tear, history of re-injury and the progression of Outerbridge changes to the articular surfaces. There was a significant risk for a revision meniscectomy in patients with horizontal/partial thickness tears compared to flap tears. No additional factor analysed was significantly associated with a revision procedure.