Proteomic analysis of radioiodine-refractory differentiated thyroid cancer identifies CHI3L1 upregulation in association with dysfunction of the sodium-iodine symporter

Radioiodine refractory differentiated thyroid cancer (RR-DTC) is the main factor adversely affecting the overall survival rate of patients with thyroid cancer. The aim of the present study was to investigate the underlying molecular mechanism of pathogenesis of RR-DTC and to explore novel therapeutic targets for clinical treatment. A proteomic analysis was performed using the tumor tissues of patients with RR-DTC. A total of 6 metastatic lymph nodes were collected during lymph node dissection, 3 from patients with RR-DTC and 3 from patients with papillary thyroid cancer. The expression of chitinase-3-like 1 (CHI3L1) and sodium-iodine symporter (NIS) in the tumor tissue was detected by immunohistochemistry (IHC). Western blotting was used to detect the expression of CHI3L1, phosphorylated (p)-MEK and p-ERK1/2 in PTC-K1 cells transfected with CHI3L1 overexpression vector. The proteomic analysis identified 665 differentially expressed proteins (DEPs), including 327 upregulated and 338 downregulated proteins in the RR-DTC group, which were enriched in 59 signaling pathways by Kyoto Encyclopedia of Genes and Genomes database analysis. In particular, CHI3L1 was demonstrated to be significantly upregulated in RR-DTC as evidenced by quantitative proteomic analysis and IHC. Western blotting suggested that the overexpression of CHI3L1 activated the MEK/ERK1/2 signaling pathway, which may lead to NIS dysfunction. In conclusion, the present study suggests that CHI3L1 is a potential molecular target for the radiotherapy of patients with RR-DTC.

The neuroinflammatory biomarker YKL-40 for neurodegenerative diseases: advances in development

Introduction: Neuroinflammation is a common pathophysiological mechanism in neurodegenerative diseases (ND). Cerebrospinal fluid (CSF) YKL-40 has recently been candidated as a neuroinflammatory biomarker of ND. Areas covered: We provide an update on the role of CSF YKL-40 as a pathophysiological biomarker of ND. YKL-40 may discriminate Alzheimer's disease (AD) from controls and may predict the progression from the early preclinical to the late dementia stage. In genetic AD, YKL-40 increases decades before the clinical onset. It does not seem a specific biomarker of a certain ND although sporadic Creutzfeldt-Jacob disease shows the highest YKL-40 concentrations. YKL-40 may discriminate between amyotrophic lateral sclerosis (ALS) and ALS-mimics. YKL-40 is potentially associated with the rate of ALS progression. YKL-40 correlates with biomarkers of neuronal injury, large axonal damage and synaptic disruption in various ND. It is not associated with the presence of the APOE-ε4 allele whereas possibly linked to aging, female sex, Hispanic ethnicity and some genetic variants of the chitinase-3-like 1 locus. Expert opinion: There is growing evidence expanding the relevance of CSF YKL-40 as a pathophysiological biomarker for ND. Patients showing high YKL-40 levels might benefit from targeted clinical trials that use compounds acting against neuroinflammatory mechanisms, independently of the initial clinical diagnosis of ND.

Cerebrospinal fluid chitinase-3-like 2 and chitotriosidase are potential prognostic biomarkers in early multiple sclerosis

BACKGROUND AND PURPOSE

The role of chitinases and chitinase-like proteins in multiple sclerosis (MS) is currently unknown; however, cerebrospinal fluid (CSF) levels of chitinase 3-like 1 (CHI3L1) predict prognosis in early MS. Whether this applies to other chitinases and chitinase-like proteins is yet to be established. Our objective was to investigate the potential of chitinase 3-like 2 (CHI3L2) and chitotriosidase as prognostic biomarkers in optic neuritis (ON) as the first demyelinating episode and to evaluate the ability of CHI3L2 to predict long-term MS risk and disability.

METHODS

In a prospective cohort of 73 patients with ON as a first demyelinating episode and 26 age-matched healthy controls levels of CHI3L2 and chitotriosidase in CSF were explored by enzyme-linked immunosorbent assay. Associations with magnetic resonance imaging white matter lesions, CSF oligoclonal bands, immunoglobulin G index and leukocyte count were investigated. Long-term MS risk and disability (Expanded Disability Status Scale, Multiple Sclerosis Functional Composite components) were examined in a retrospective cohort of 78 patients with ON as the first demyelinating episode (mean follow-up 14 years). The predictive ability of CHI3L2 was compared with CHI3L1.

RESULTS

Cerebrospinal fluid levels of CHI3L2 and chitotriosidase were significantly elevated in patients with ON and were associated with MS risk measures. CHI3L2 levels predicted MS development after ON (hazard ratio 1.95, P = 0.00039, Cox regression) and cognitive impairment by the Paced Auditory Serial Addition Test (P = 0.0357, linear regression) at follow-up. In a multivariate analysis of MS risk, CHI3L2 performed better than CHI3L1.

CONCLUSIONS

CHI3L2 and chitotriosidase are promising biomarkers in patients with a first demyelinating episode. Our findings thus support a role for these proteins as biomarkers in early MS.