Thalidomide inhibits adipogenesis of orbital fibroblasts in Graves' ophthalmopathy

PPAR agonists attenuate lenalidomide's anti-myeloma activity in vitro and in vivo

Many patients with multiple myeloma (MM) have comorbidities and are treated with PPAR agonists. Immunomodulatory agents (IMiDs) are the cornerstones for MM therapy. Currently, little is known about how co-administration of PPAR agonists impacts lenalidomide treatment in patients with MM. Here, we determined the effects of PPAR agonists on anti-myeloma activities of lenalidomide in vitro and in a myeloma xenograft mouse model. Genetic overexpression and CRISPR/cas9 knockout experiments were performed to determine the role of CRBN in the PPAR-mediated pathway. A retrospective cohort study was performed to determine the correlation of PPAR expression with the outcomes of patients with MM. PPAR agonists down-regulated CRBN expression and reduced the anti-myeloma efficacy of lenalidomide in vitro and in vivo. Co-treatment with PPAR antagonists increased CRBN expression and improved sensitivity to lenalidomide. PPAR expression was higher in bone marrow cells of patients with newly diagnosed MM than in normal control bone marrow samples. High PPAR expression was correlated with poor clinical outcomes. Our study provides the first evidence that PPARs transcriptionally regulate CRBN and that drug-drug interactions between PPAR agonists and IMiDs may impact myeloma treatment outcomes.

PD-L1 Inhibits T Cell-Induced Cytokines and Hyaluronan Expression via the CD40-CD40L Pathway in Orbital Fibroblasts From Patients With Thyroid Associated Ophthalmopathy

Thyroid associated ophthalmopathy (TAO), characterized by T cell infiltration and orbital fibroblast activation, is an organ-specific autoimmune disease which is still short of effective and safety therapeutic drugs. The PD-1/PD-L1 pathway has been reported hindering the progression of Graves’ disease to some extent by inhibiting T cell activity, and tumor therapy with a PD-1 inhibitor caused some adverse effects similar to the symptoms of TAO. These findings suggest that the PD-1/PD-L1 pathway may be associated with the pathogenesis of TAO. However, it remains unknown whether the PD-1/PD-L1 pathway is involved in orbital fibroblast activation. Here, we show that orbital fibroblasts from patients with TAO do not express PD-L1. Based on in vitro OF-T cell co-culture system, exogenous PD-L1 weakens T cell-induced orbital fibroblast activation by inhibiting T cell activity, resulting in reduced production of sICAM-1, IL-6, IL-8, and hyaluronan. Additionally, exogenous PD-L1 treatment also inhibits the expression of CD40 and the phosphorylation levels of MAPK and NF-κB pathways in orbital fibroblasts of the OF-T cell co-culture system. Knocking down CD40 with CD40 siRNA or down-regulating the phosphorylation levels of MAPK and NF-κB pathways with SB203580, PD98059, SP600125, and PDTC can both reduce the expression of these cytokines and hyaluronan. Our study demonstrates that the orbital immune tolerance deficiency caused by the lack of PD-L1 in orbital fibroblasts may be one of the causes for the active orbital inflammation in TAO patients, and the utilization of exogenous PD-L1 to reconstruct the orbital immune tolerance microenvironment may be a potential treatment strategy for TAO.

Insulin‑like growth factor I promotes adipogenesis in hemangioma stem cells from infantile hemangiomas

Infantile hemangiomas (IH) are the most common infantile neoplasms and are characterized by initial proliferation during infancy and subsequent spontaneous regression within the next 5‑10 years, frequently leaving fibrous fat residues. However, the specific mechanisms underlying the differentiation of hemangioma stem cells (HemSCs) into adipocytes are not clear. The purpose of the present study was to investigate the effect of insulin‑like growth factor I (IGF‑1) on HemSCs from patients with IH and to determine the signaling mechanisms involved. Treatment of HemSCs with IGF‑1 led to upregulation of the protein expression levels of peroxisome proliferator‑activated receptor‑γ (PPARγ). By contrast, inhibition of the IGF‑1 receptor (IGF‑1R) or phosphoinositide 3‑kinase (PI3K) activity decreased the expression of PPARγ, in addition to that of CCAAT/enhancer‑binding protein (C/EBP)α, C/EBPβ, and adiponectin. IGF‑1 upregulated the expression of phosphorylated RAC‑α serine/threonine‑protein kinase in IH cells, whereas a specific PI3K inhibitor or IGF‑1R antibody blocked this effect. These results indicated that IGF‑1 is a pro‑proliferative and pro‑lipogenic factor in IH HemSCs. Taken together, these findings indicated that IGF‑1 is able to upregulate PPARγ by activating the IGF‑1R and PI3K pathways, thereby accelerating lipogenesis and enhancing IH HemSC adipogenesis.

Lenalidomide-Associated Thyroid-Related Eyelid Retraction

Several antineoplastic treatments have been responsible for thyroid dysfunction and thyroid eye disease. Min, Vaidya, and Becker (2011) reported a case of euthyroid Graves orbitopathy after treatment with ipilimumab with the patient displaying proptosis and myositis in the setting of normal thyroid function tests and elevated thyroid antibodies. The authors report a case of a 76-year-old woman who developed right upper lid retraction and proptosis after 2.5 years of treatment with lenalidomide for multiple myeloma. Thyroid function tests were normal: thyroid-stimulating hormone 0.808 mIU/mL, total T3 102 ng/dL, free T4 1.48 ng/dL. Thyroid antibodies were elevated: thyrotropin receptor antibody 2.26 IU/L, thyroglobulin antibody 1043.1 IU/mL, and thyroid peroxidase antibody 38 IU/mL. A nuclear medicine thyroid scan was normal. Given the possible thyroid effects from lenalidomide, patients who receive this medication should be periodically evaluated for thyroid dysfunction and thyroid eye disease.

Meta-analysis of methylprednisolone pulse therapy for Graves' ophthalmopathy

A meta-analysis was performed to evaluate the efficacy of methylprednisolone pulse therapy for Graves' ophthalmopathy. Eight studies involving 376 patients were included. A higher effective rate was found for patients treated with intravenous glucocorticoids (IVGC) over oral glucocorticoids (OGC) (risk ratio [RR] = 1.48; 95% confidence interval [CI] = 1.18-1.86). The combined IVGC and orbital radiotherapy (OR) was markedly more effective than OGC+OR (RR = 1.40; 95% CI = 1.11-1.77). IVGC resulted in an obvious reduction of clinical activity score (CAS) compared with OGC, with a weighted mean difference (WMD) of 0.86 (95% CI = 0.53-1.18). The WMD for the reduction of the CAS between IVGC+OR and OGC+OR was 0.66 (95% CI = 0.30-1.02). IVGC is an effective treatment and cause fewer adverse events. Limiting the total cumulative dose of methylprednisolone, careful patient selection and monitoring the condition of patients during treatment are necessary.

Mechanism of immunomodulatory drugs' action in the treatment of multiple myeloma

Although immunomodulatory drugs (IMiDs), such as thalidomide, lenalidomide, and pomalidomide, are widely used in the treatment of multiple myeloma (MM), the molecular mechanism of IMiDs' action is largely unknown. In this review, we will summarize recent advances in the application of IMiDs in MM cancer treatment as well as their effects on immunomodulatory activities, anti-angiogenic activities, intervention of cell surface adhesion molecules between myeloma cells and bone marrow stromal cells, anti-inflammatory activities, anti-proliferation, pro-apoptotic effects, cell cycle arrest, and inhibition of cell migration and metastasis. In addition, the potential IMiDs' target protein, IMiDs' target protein's functional role, and the potential molecular mechanisms of IMiDs resistance will be discussed. We wish, by presentation of our naive discussion, that this review article will facilitate further investigation in these fields.

Insulin-like growth factor 1 promotes the proliferation and adipogenesis of orbital adipose-derived stromal cells in thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is characterised by increased volume of the orbital contents involving adipose tissue, but the factors responsible for stimulation of orbital adipogenesis remain uncertain. Previous studies have shown that insulin-like growth factor 1 (IGF-1) is increased in the orbital fatty connective tissues of patients with TAO. The present study was conducted to investigate the effects of IGF-1 on orbital adipose-derived stromal cells (OADSCs) derived from TAO patients and to identify the signalling mechanisms involved. Our results showed that IGF-1 significantly promoted the cell proliferation and lipid accumulation of TAO OADSCs. The mRNA expression of adipogenic markers (adiponectin, leptin, adipocyte fatty acid binding protein [AP2] and fatty acid synthase [FAS]) was increased in TAO cultures treated with IGF-1. Further research demonstrated that the protein levels of peroxisome proliferator-activated receptor-γ (PPARγ) were up-regulated when OADSCs were treated with IGF-1. We also found that the inhibition of either IGF-1 receptor (IGF-1R) or phosphoinositide 3-kinase (PI3K) activity decreased the levels of IGF-1-stimulated mRNA encoding adiponectin, leptin, AP2, and FAS, as well as PPARγ protein levels. Moreover, the expression of phosphorylated Akt (p-Akt) protein in TAO cells was up-regulated by IGF-1, while a specific PI3K inhibitor (LY294002) or an antibody of IGF-1R blocked this effect. These results indicate that IGF-1 is a pro-proliferative and pro-adipogenic factor in TAO OADSCs. IGF-1 enhances the adipogenesis of TAO OADSCs by up-regulation of PPARγ via the activation of the IGF-1R and PI3K pathways, suggesting that the blocking of IGF-1R or inhibition of PI3K signalling might be a potential novel therapeutic approach to TAO.