Microenvironmental Modulation of Decorin and Lumican in Temozolomide-Resistant Glioblastoma and Neuroblastoma Cancer Stem-Like Cells

The presence of cancer stem cells (CSCs) or tumor-initiating cells can lead to cancer recurrence in a permissive cell–microenvironment interplay, promoting invasion in glioblastoma (GBM) and neuroblastoma (NB). Extracellular matrix (ECM) small leucine-rich proteoglycans (SLRPs) play multiple roles in tissue homeostasis by remodeling the extracellular matrix (ECM) components and modulating intracellular signaling pathways. Due to their pan-inhibitory properties against receptor tyrosine kinases (RTKs), SLRPs are reported to exert anticancer effects in vitro and in vivo. However, their roles seem to be tissue-specific and they are also involved in cancer cell migration and drug resistance, paving the way to complex different scenarios. The aim of this study was to determine whether the SLRPs decorin (DCN) and lumican (LUM) are recruited in cell plasticity and microenvironmental adaptation of differentiated cancer cells induced towards stem-like phenotype. Floating neurospheres were generated by applying CSC enrichment medium (neural stem cell serum-free medium, NSC SFM) to the established SF-268 and SK-N-SH cancer cell lines, cellular models of GBM and NB, respectively. In both models, the time-dependent synergistic activation of DCN and LUM was observed. The highest DCN and LUM mRNA/protein expression was detected after cell exposure to NSC SFM for 8/12 days, considering these cells as SLRP-expressing (SLRP+) CSC-like. Ultrastructural imaging showed the cellular heterogeneity of both the GBM and NB neurospheres and identified the inner living cells. Parental cell lines of both GBM and NB grew only in soft agar + NSC SFM, whereas the secondary neurospheres (originated from SLRP+ t8 CSC-like) showed lower proliferation rates than primary neurospheres. Interestingly, the SLRP+ CSC-like from the GBM and NB neurospheres were resistant to temozolomide (TMZ) at concentrations >750 μM. Our results suggest that GBM and NB CSC-like promote the activation of huge quantities of SLRP in response to CSC enrichment, simultaneously acquiring TMZ resistance, cellular heterogeneity, and a quiescent phenotype, suggesting a novel pivotal role for SLRP in drug resistance and cell plasticity of CSC-like, allowing cell survival and ECM/niche modulation potential.This study was supported by Fundació la Marató TV3, Project n° 111431

Rotavirus-specific T cell responses and cytokine mRNA expression in children with diabetes-associated autoantibodies and type 1 diabetes

Rotavirus infections have been implicated as a possible trigger of type 1 diabetes. We elucidated this connection by comparing peripheral blood T cell responses to rotavirus between children with newly diagnosed type 1 diabetes (n = 43), healthy children with multiple diabetes-associated autoantibodies (n = 36) and control children carrying human leukocyte antigen (HLA)-conferred susceptibility to type 1 diabetes but without autoantibodies (n = 104). Lymphocyte proliferation assays based on stimulation with an antigen were performed using freshly isolated peripheral blood mononuclear cells (PBMC) and IgG and IgA class rotavirus antibodies were measured using plasma samples collected from the children. The expression of interferon (IFN)-γ, interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-β in PBMC was studied with real-time polymerase chain reaction (PCR) in a subgroup of 38 children. No differences were observed in the strength or frequency of positive T cell responses to rotavirus between children with overt diabetes, children with multiple autoantibodies and control children. Children with diabetes-associated autoantibodies had, instead, stronger T cell responses to purified coxsackie B4 virus than control children. Rotavirus-stimulated lymphocytes from autoantibody-positive children produced more IL-4 and phytohaemagglutinin (PHA)-stimulated lymphocytes more IL-4 and IFN-γ than lymphocytes from control children. PHA-stimulated lymphocytes from children with diabetes also produced more IL-4 and purified protein derivative (PPD)-stimulated lymphocytes less TGF-β than lymphocytes from autoantibody-negative control children. In conclusion, our lymphocyte proliferation studies did not provide evidence supporting an association between rotavirus infections and the development of type 1 diabetes or diabetes-associated autoantibodies in young children

Evidence from twins for acquired cellular immune hyperactivity in type 1 diabetes

Type 1 diabetes has been associated with an increased frequency of activated T cells and T-cell hyperactivity to non-specific and disease-specific stimuli including the islet autoantigen glutamic acid decarboxylase 65 (GAD). To address whether T-cell hyperactivity is genetic or acquired we measured whole blood cytokines in vitro in response to GAD or tetanus in 18 identical twin pairs, nine discordant for type 1 diabetes. In addition, the activity of 2′, 5′ oligoadenylate synthetase (OAS) in blood mononuclear cells was measured as a marker of viral infection. Interleukin-2 (IL-2) basally and IL-2 and interferon-γ (IFN-γ) in response to GAD, were detected more frequently and at higher levels in diabetic compared to non-diabetic twins. IL-10 was not different between groups. OAS activity was increased in diabetic compared to non-diabetic twins and showed a correlation with basal IL-2 and GAD-stimulated IFN-γ and IL-10. These findings suggest that T-cell hyperactivity in type 1 diabetes is an acquired trait and could reflect persisting virus expression