miR-214 aggravates oxidative stress in thalassemic erythroid cells by targeting ATF4.

Oxidative damage to erythroid cells plays a key role in the pathogenesis of thalassemia. The oxidative stress in thalassemia is potentiated by heme, nonheme iron, and free iron produced by the Fenton reaction, due to degradation of the unstable hemoglobin and iron overload. In addition, the levels of antioxidant enzymes and molecules are significantly decreased in erythrocytes in α- and ß-thalassemia. The control of oxidative stress in red blood cells (RBCs) is known to be mediated by microRNAs (miRNAs). In erythroid cells, microR-214 (miR-214) has been reported to respond to external oxidative stress. However, the molecular mechanisms underlying this phenomenon remain unclear, especially during thalassemic erythropoiesis. In the present study, to further understand how miR-214 aggravates oxidative stress in thalassemia erythroid cells, we investigated the molecular mechanism of miR-214 and its regulation of the oxidative status in thalassemia erythrocytes. We have reported a biphasic expression of miR-214 in ß- and α-thalassemia. In the present study the effect of miR-214 expression was investigated by using miR -inhibitor and -mimic transfection in erythroid cell lines induced by hemin. Our study showed a biphasic expression of miR-214 in ß- and α-thalassemia. Subsequently, we examined the effect of miR-214 on erythroid differentiation in thalassemia. Our study reveals the loss-of-function of miR-214 during translational activation of activating transcription factor 4 mRNA, leading to decreased reactive oxygen species levels and increased glutathione levels in thalassemia erythroid cell. Our results suggest that the expression of activating transcription factor 4 regulated by miR-214 is important for oxidative stress modulation in thalassemic erythroid cells. Our findings can help to better understand the molecular mechanism of miRNA and transcription factors in regulation of oxidative status in erythroid cells, particularly in thalassemia, and could be useful for managing and relieving severe anemia symptoms in patients in the future.

Latex C-serum from Hevea brasiliensis induces apoptotic cell death in a leukemic cell line.

BACKGROUND: Hevea brasiliensis latex is generally cultivated for the use of rubber particles. Previous studies have shown that the antiproliferative activity of C-serum in hepatocellular carcinoma is not induced through the classical apoptotic signaling pathway. However, in a leukemic cell line, the anti-proliferation effect of latex C serum remained unclear. METHODS: Leukemic cell lines (K562 and U937) and human peripheral blood mononuclear cells (PBMCs) were examined for cell viability using the MTT assay. Flow cytometry was used for apoptotic cell detection by annexin V/PI staining. The expression levels of proapoptotic and antiapoptotic marker genes were measured by qRT‒PCR. Moreover, the caspase activities of the extrinsic and intrinsic apoptotic pathways were detected by enzymatic activities. RESULTS: Latex C-serum inhibited cell proliferation in the K562 and U937 leukemic cell lines but did not affect human PBMCs. Latex C-serum significantly induced the percentage of early and late apoptotic cells in the leukemic cell line. The expression levels of the pro-apoptotic marker genes BAD, BAX, and CASPASE3 significantly increased in the leukemic cell line after post-latex C-serum leukemic cell treatment. The extrinsic, intrinsic and common apoptotic pathways were also studied through caspase-8, -9, and -3 activities. Latex C-serum treatment significantly induced caspase-8, -9, and -3 activation in the K562 cell line and U937 cell line compared to the untreated cells. CONCLUSIONS: These results indicate that latex C-serum enhanced anti-proliferation in leukemic cell lines by inducing apoptosis and caspase activation.

Microsatellite instability and oncological outcomes in Thai patients with endometrial cancer.

Here, we determined the frequency of microsatellite instability (MSI) and the impact of MSI-high (MSI-H) on clinical outcomes of Thai patients with endometrial cancer (EC). Tissue samples of 110 Thai patients with EC, who had undergone surgical staging, were tested for mismatch repair (MMR) gene deficiency, and the patients were grouped into MSI-H and MSI-stable (MSI-S) groups; 24.5% had MSI-H. Unlike MSI-S group patients, MSI-H group patients had synchronous and metachronous cancer. They showed better 3-year disease-free survival (DFS) than those in the MSI-S group (p=.182; 92.3% vs. 82.6%). The 3-year overall survival was 96.2% in MSI-H and 86.4% in MSI-S groups (p=.163). Multivariate analyses showed lower uterine involvement (p=.004), myometrial invasion ≥50% (p=.032), lymphovascular space invasion (p<.001) and MSI-S (p=.006) as prognostic factors for DFS. Our study showed that the prevalence of MMR gene deficiency in Thai patients with EC is common and associated with better outcomes.Impact StatementWhat is already known on this subject? Microsatellite instability (MSI) occurs in approximately 20-40% of endometrial cancer (EC) cases. MSI analysis in EC can identify patients at higher risk of hereditary nonpolyposis colorectal cancer and those having prognostic factors. Additionally, it is predictive of immune checkpoint inhibitor treatment. However, current evidence shows a correlation between clinicopathological characteristics and EC prognosis. Studies on EC and MSI status effect on survival outcome have yielded inconsistent results regarding the pathological significance of MSI in such malignancies.What do the results of this study add? The prevalence of mismatch repair (MMR) gene deficiency in Thai patients with EC is common (24.5%) and associated with better outcomes.What are the implications of these findings for clinical practice and/or further research? This study highlights the prevalence and impact of MSI on oncological outcomes in patients with EC in a low-incidence country. Future studies should focus on the detection of germline mutation to understand the accurate prevalence of Lynch syndrome in Thai patients with EC.