Human mesenchymal stromal cells modulate T-cell immune response via transcriptomic regulation

Background aims: Mesenchymal stromal cells (MSCs) have been identified as pan-immunosuppressant in various in vitro and in vivo inflammatory models. Although the immunosuppressive activity of MSCs has been explored in various contexts, the precise molecular signaling pathways that govern inhibitory functions remain poorly elucidated. Methods: By using a microarray-based global gene expression profiling system, this study aimed to decipher the underlying molecular pathways that may mediate the immunosuppressive activity of umbilical cord–derived MSCs (UC-MSCs) on activated T cells. Results: In the presence of UC-MSCs, the proliferation of activated T cells was suppressed in a dose-depended manner by cell-to-cell contact mode via an active cell-cycle arrest at the G0/G1 phase of the cell cycle. The microarray analysis revealed that particularly, IFNG, CXCL9, IL2, IL2RA and CCND3 genes were down-regulated, whereas IL11, VSIG4, GFA1, TIMP3 and BBC3 genes were up-regulated by UC-MSCs. The dysregulated gene clusters associated with immune-response-related ontologies, namely, lymphocyte proliferation or activation, apoptosis and cell cycle, were further analyzed. Conclusions: Among the nine canonical pathways identified, three pathways (namely T-helper cell differentiation, cyclins and cell cycle regulation, and gap/tight junction signalling pathways) were highly enriched with these dysregulated genes. The pathways represent putative molecular pathways through which UC-MSCs elicit immunosuppressive activity toward activated T cells. This study provides a global snapshot of gene networks and pathways that contribute to the ability of UC-MSCs to suppress activated T cells

miR-137-mediated loss of KDM5B expression leads to suppression of the malignant phenotype of bladder cancer cells

The oncogenic role of KDM5B is implicated in the pathogenesis of many cancers including bladder cancer (BC). KDM5B is a histone demethylase enzyme that modifies the chromatin structure to specify cellular transcriptional states. Overexpression of KDM5B in cancer cells is correlated with an increased proliferative capacity. Intriguingly, KDM5B is a cancer/testis antigen; while its expression in tumours is ectopically amplified, KDM5B expression in normal conditions is limited to embryonic stem cells (ESCs) and the testis in adults. These unique characteristics make KDM5B a potential pan-cancer therapeutic target. Thus, this study was aimed at identifying potential regulators of KDM5B. Since KDM5B expression in ESCs is orchestrated by microRNAs (miRNAs) and the expression of many miRNAs are altered in BC, we hypothesized that miRNAs may be the switch that can abate KDM5B expression to mitigate the BC malignant phenotype. Based on IHC- and RT-QPCR analysis, we found that KDM5B protein and transcript levels were differentially expressed in cancer tissues and cell lines, respectively. Amongst several in silico-predicted putative KDM5B-targeting miRNAs, the in vitro basal expression of miR-137 was inversely correlated with KDM5B expression. We demonstrated that the overexpression of miR-137 significantly attenuated KDM5B expression, induced G1 cell-cycle arrest, suppressed cell growth and blocked invasion and migration of BC cells. In contrast, downregulation of miR-137 expression led to the reverse effect. By integrating in silico screens of miR-137 putative target genes and microarray data using the Ingenuity Pathway Analysis (IPA), we revealed that miR-137 possibly exerts control over the cell-cycle through Rb and adenylyl cyclic signalling pathways by targeting key regulators of cyclin A. We also showed that miR-137 gain-of-function increased the expression of tumor suppressor, JDP2. While our results suggest that miR-137 can mitigate the KDM5B-associated BC phenotype, further studies on understanding the effect on aberrant histone methylation patterns are warranted

Overexpression of CTAG1B is a potential biomarker in bladder cancer

Urothelial cell carcinoma (UCC) is the most common form of bladder cancer and is associated with the need for life-long surveillance once a patient is diagnosed with a non-invasive disease. Due to the long-term risk of recurrence and the need for life-long routine monitoring and therapy, the cost per UCC patient from diagnosis to death is the highest of all cancers. The development of non-invasive biomarkers of recurrence and progression can increase survival, decrease treatment costs and improve patient quality of life. However, to date, no biomarker(s) have been endorsed for the use in the clinical management of UCC, especially in predicting risk of progression and recurrence. CTAG1B was previously found to be highly expressed in high-stage and grade bladder cancer, albeit in Caucasian cohorts. However, despite its potential as a target for cancer immunotherapy, the effect of expression modulation on cellular phenotypes has never been reported. In this study, we overexpressed CTAG1B in an invasive bladder cancer cell line, EJ28 after we confirmed that this cell line minimally expressed CTAG1B. The cells were transfected with CTAG1B-pcDNA3.1(-) and the level of expression was confirmed by qRT-PCR. Once the expression was confirmed to persist up to 72h post-transfection, the transfected cells were subjected to various phenotypic assays. In addition, the pattern of CTAG1B expression in a cohort of Malaysian bladder cancer paraffin-embedded tissues was also determined using immunohistochemistry. The effect of CTAG1B overexpression on the cell cycle, migratory and proliferative potential was observed. The changes in phenotype were compared with that of untransfected and mock controls. CTAG1B was overexpressed 20 times as compared to the untransfected and mock controls in the transfected cells. CTAG1B overexpression resulted in cells to migrate slower at 24h post-transfection but proliferate significantly faster after 72-96h post-transfection. In addition, CTAG1B was more frequently expressed in advanced bladder cancer stages and grades. The findings from this study contribute to the current knowledge of CTAG1B‟s role in tumourigenesis. Further functional studies will contribute towards realising the potential of CTAG1B as a biomarker for predicting the risk of progression and recurrence of bladder cancer