A rapid and simple non-radioactive assay for measuring uptake by solute carrier transporters.

Introduction: Solute carrier (SLC) transport proteins play a crucial role in maintaining cellular nutrient and metabolite homeostasis and are implicated in various human diseases, making them potential targets for therapeutic interventions. However, the study of SLCs has been limited due to the lack of suitable tools, particularly cell-based substrate uptake assays, necessary for understanding their biological functions and for drug discovery purposes. Methods: In this study, a cell-based uptake assay was developed using a stable isotope-labeled compound as the substrate for SLCs, with detection facilitated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This assay aimed to address the limitations of existing assays, such as reliance on hazardous radiolabeled substrates and limited availability of fluorescent biosensors. Results: The developed assay was successfully applied to detect substrate uptakes by two specific SLCs: L-type amino acid transporter 1 (LAT1) and sodium taurocholate co-transporting polypeptide (NTCP). Importantly, the assay demonstrated comparable results to the radioactive method, indicating its reliability and accuracy. Furthermore, the assay was utilized to screen for novel inhibitors of NTCP, leading to the identification of a potential NTCP inhibitor compound. Discussion: The findings highlight the utility of the developed cell-based uptake assay as a rapid, simple, and environmentally friendly tool for investigating SLCs' biological roles and for drug discovery purposes. This assay offers a safer alternative to traditional methods and has the potential to contribute significantly to advancing our understanding of SLC function and identifying therapeutic agents targeting SLC-mediated pathways.

Corrigendum: Prostaglandin reductase 1 as a potential therapeutic target for cancer therapy.

[This corrects the article DOI: 10.3389/fphar.2021.717730.].

Prostaglandin Reductase 1 as a Potential Therapeutic Target for Cancer Therapy.

Altered tumor metabolism is a hallmark of cancer and targeting tumor metabolism has been considered as an attractive strategy for cancer therapy. Prostaglandin Reductase 1 (PTGR1) is a rate-limiting enzyme involved in the arachidonic acid metabolism pathway and mainly responsible for the deactivation of some eicosanoids, including prostaglandins and leukotriene B4. A growing evidence suggested that PTGR1 plays a significant role in cancer and has emerged as a novel target for cancer therapeutics. In this review, we summarize the progress made in recent years toward the understanding of PTGR1 function and structure, highlight the roles of PTGR1 in cancer, and describe potential inhibitors of PTGR1. Finally, we provide some thoughts on future directions that might facilitate the PTGR1 research and therapeutics development.

[Analysis of SPTA1 gene mutations in a patient with hereditary elliptocytosis].

OBJECTIVE: To detect disease-causing mutations in a patient with hereditary elliptocytosis. METHODS: Sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) was used to identify the type of erythrocyte membrane protein defect. Potential mutations of the exons and adjacent introns of relevant genes were analyzed by Sanger sequencing. RESULTS: SDS-PAGE has failed to detect any difference between the patient and healthy controls. However, Sanger sequencing has detected three mutations in the SPTA1 gene in the patient, which included c.5077A>C (p.Lys1693Gln) missense mutation in exon 36, c.5572C>G (p.Leu1858Val) missense mutation in exon 40, and a IVS45nt-12C>T in intron 45. The father and grandmother of the patient were both heterozygous for c.5077A>C mutation, while her mother was heterozygous for c.5572C>G and IVS45nt-12C>T mutations. CONCLUSION: The hereditary elliptocytosis in the patient may be attributed to the synergistic action of c.5077A>C, c.5572C>G and IVS45nt-12C>T mutations of the SPTA1 gene.

Protective effect of retinoic acid receptor α on hypoxia-induced epithelial to mesenchymal transition of renal tubular epithelial cells associated with TGF-ß/MMP-9 pathway.

Retinoic acid receptor α (RARα), a member of family of the nuclear retinoic acid receptors (RARs), plays an essential role in various chronic kidney diseases (CKD). Renal tubular epithelial to mesenchymal transition (EMT) is a common mechanism of progression of renal interstitial fibrosis (RIF). Hypoxia has been extensively considered as one of major inducers of renal tubular EMT. However, the effects of RARα on hypoxia-induced EMT have not yet been described so far. The aim of the present study was to explore the roles and potential mechanisms of RARα in hypoxia-induced EMT of renal tubular epithelial cells (RTECs). Our results showed that expression of RARα in RTECs subjected to hypoxia significantly was reduced, accompanied by decreased expression level of the epithelial marker E-cadherin, and increased expression levels of the mesenchymal markers α-smooth muscle actin (α-SMA) and vimentin, in accord with EMT. Meanwhile, hypoxia could cause RTECs to obviously express TGF-ß and matrix metalloproteinase-9 (MMP-9). Furthermore, using lentivirus-based delivery vectors to overexpress RARα in RTECs, we demonstrated that RARα alleviated hypoxia-induced EMT of RTECs and downregulated the expression levels of TGF-ß and MMP-9. In a word, RARα protects RTECs against EMT induced by hypoxia associated with TGF-ß/MMP-9 pathway.

Decreased expression of microRNA-126 is associated with poor prognosis in patients with cervical cancer.

BACKGROUND: MicroRNA-126(miR-126) has been shown to be frequently down-regulated in a variety of malignancies and act as a potential tumor suppressor. However, its correlations with the clinicopathological characters of cervical cancer remain unclear. METHODS: TaqMan quantitative RT-PCR was used to determine the expression level of miR-126 in tissue samples. The associations of miR-126 expression with clinicopathologic variables were analyzed. Kaplan-Meier survival analysis was performed to analyze the association of miR-126 expression with overall survival (OS) of patients. Univariate and multivariate Cox regression analyses were performed. RESULTS: miR-126 expression level in human cervical cancer tissues was significantly lower than that in adjacent nontumorous tissues (mean ± SD: 0.59 ± 0.44 vs. 1.00 ± 0.51, P < 0.0001). Decreased miR-126 expression in cervical cancer was found to be significantly associated with lymphatic invasion (P = 0.002), distant metastasis (P < 0.001), FIGO stage (P = 0.009), and histological grade (P = 0.005). Kaplan-Meier analysis showed that patients with lower levels of miR-126 had significantly poorer survival than those with higher expression of this miRNA in patients, with a 5-year OS of 45.7% and 70.9%, respectively (P = 0.002). Multivariate analysis revealed that miR-126 expression (HR = 3.97, 95% CI: 2.01-20.22; P = 0.003) was independently associated with the OS. CONCLUSION: Our data suggests the potential of miR-126 as a prognostic biomarker for cervical cancer. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_220.