Downregulation of miR-135b-5p Suppresses Progression of Esophageal Cancer and Contributes to the Effect of Cisplatin

Highly homologous miR-135a and miR-135b converting non-small cell lung cancer from suppression to progression via enhancer switching

microRNAs (miRNAs) are short non-coding RNAs that have been increasingly recognized for their significant roles in the progression of cancer. Distinct miRNAs exhibit diverse functions attributed to variations in their sequences. As a result of possessing highly homologous seed sequences, these miRNAs target overlapping or similar gene sets, thus performing analogous roles. However, different from this sight, our study discovered that miR-135a-5p and miR-135b-5p, despite differing by only one nucleotide, exhibit distinct functional roles. Using non-small cell lung cancer (NSCLC) as a paradigm, our findings unveiled the downregulation of miR-135a-5p and upregulation of miR-135b-5p within NSCLC through TCGA database. Consequently, we further investigated their functional differences in A549 cells. Overexpression of miR-135b-5p enhanced the proliferation and migration capabilities of A549 cells, whereas miR-135a-5p transfection exhibited the opposite effect. We demonstrated that the activation of specific enhancers serves as a crucial mechanism underlying the disparate functions exerted by miR-135a-5p and miR-135b-5p in the context of NSCLC, consequently instigating a shift from inhibition to activation in NSCLC progression. Finally, we validated through animal experiments that miR-135b-5p promoted tumor progression, while miR-135a-5p exerted inhibitory effects on NSCLC development. This study offers a novel perspective for researchers to elucidate functional disparities exhibited by highly homologous miRNAs (miR-135a-5p and miR-135b-5p) in the context of NSCLC, along with the transition from inhibitory to progressive states in NSCLC. This study provides a solid foundation for future investigations into the functional roles of highly homologous miRNAs in pathological situation.

The role of TXNIP in cancer: a fine balance between redox, metabolic, and immunological tumor control

Thioredoxin-interacting protein (TXNIP) is commonly considered a master regulator of cellular oxidation, regulating the expression and function of Thioredoxin (Trx). Recent work has identified that TXNIP has a far wider range of additional roles: from regulating glucose and lipid metabolism, to cell cycle arrest and inflammation. Its expression is increased by stressors commonly found in neoplastic cells and the wider tumor microenvironment (TME), and, as such, TXNIP has been extensively studied in cancers. In this review, we evaluate the current literature regarding the regulation and the function of TXNIP, highlighting its emerging role in modulating signaling between different cell types within the TME. We then assess current and future translational opportunities and the associated challenges in this area. An improved understanding of the functions and mechanisms of TXNIP in cancers may enhance its suitability as a therapeutic target.

The role of miRNAs and lncRNAs in neurofibromatosis type 1

Neurofibromatosis Type 1 (NF1) is a frequent cancer predisposition syndrome. The common hallmark of patients with this multisystemic genetic disorder is the formation of peripheral nerve sheath tumors, which can be seen as either dermal, plexiform, and malignant forms. MicroRNA (miRNA) is an essential gene regulation factor and consists of 22-25 nucleotides. MiRNAs are identified to act as both tumor suppressors and oncogenes (oncomirs) in a wide variety of human cancers. They play multiple roles in molecular pathways responsible for tumor homing, progression, and invasion. Long noncoding RNA (lncRNA) also has a key role in cancer transcriptomics. Altered lncRNA expression levels have been found in various malignancies. This review aims to summarize the role of two noncoding RNA groups, miRNAs and lncRNAs, in NF1 establishment, development, and progression. We also highlight their potential for future clinical interventions and devising new diagnostic tools.

A review on the importance of miRNA-135 in human diseases

MicroRNA-135 (miR-135) is a microRNA which is involved in the pathoetiology of several neoplastic and non-neoplastic conditions. Both tumor suppressor and oncogenic roles have been reported for this miRNA. Studies in prostate, renal, gallbladder and nasopharyngeal cancers as well as glioma have shown down-regulation of miR-135 in cancerous tissues compared with controls. These studies have also shown the impact of miR-135 down-regulation on enhancement of cell proliferation and aggressive behavior. Meanwhile, miR-135 has been shown to be up-regulated in bladder, oral, colorectal and liver cancers. Studies in breast, gastric, lung and pancreatic cancers as well as head and neck squamous cell carcinoma have reported dual roles for miR-135. Dysregulation of miR-135 has also been noted in various non-neoplastic conditions such as Alzheimer’s disease, atherosclerosis, depression, diabetes, Parkinson, pulmonary arterial hypertension, nephrotic syndrome, endometriosis, epilepsy and allergic conditions. In the current review, we summarize the role of miR-135 in the carcinogenesis as well as development of other disorders.

MicroRNA-135b-5p regulates trophoblast cell function by targeting phosphoinositide-3-kinase regulatory subunit 2 in preeclampsia

The level of miR‑135b-5p is lower in patients with preeclampsia (PE) superimposed on chronic hypertension than in healthy controls. However, the function of miR‑135b-5p in PE progression remains unknown. In the present study, we investigated the role of miR‑135b-5p in PE development and its possible mechanism for the first time. HTR8/SVneo cells (trophoblast cell line) were exposed to hypoxia/reoxygenation (H/R) to mimic PE in vitro. Hypoxia-inducible factor-1α (HIF-1α), forkhead box O3A (FOXO3a), and miR-135b-5p levels were measured using Real-time PCR. Cell proliferation, apoptosis and migration/invasion were evaluated using the Cell Counting Kit-8 (CCK-8), flow cytometry and transwell assays, respectively. Real-time PCR and Western blotting were performed to determine the levels of several pro- and anti-angiogenic factors. The binding of miR-135b-5p to the PIK3R2-3’ untranslated region (3ʹUTR) was confirmed by bioinformatics analysis and a dual-luciferase reporter assay. H/R exposure greatly upregulated HIF-1α, FOXO3a, and PIK3R2 levels, while downregulating miR-135b-5p levels in HTR8/SVneo cells. H/R exposure resulted in the inhibition of proliferation, migration, invasion, angiogenesis, and the induction of apoptosis. MiR-135b-5p overexpression reversed the effects of H/R on trophoblast cell function, while miR-135b-5p knockdown enhanced the effects. PIK3R2 knockdown had similar effects as miR-135b-5p overexpression on proliferation, apoptosis and angiogenesis. The effect of miR-135b-5p overexpression on H/R-exposed cells was enhanced by PIK3R2 knockdown. MiR-135b-5p downregulated PIK3R2 expression by pairing with its 3ʹUTR. Therefore, miR-135b-5p may regulate trophoblast function by targeting PIK3R2 in PE and could serve as a novel therapeutic target for PE.

microRNA-569 inhibits tumor metastasis in pancreatic cancer by directly targeting NUSAP1

MicroRNAs (miRNAs) are known to be involved in the development and progression of pancreatic cancer (PC). In this study, the prognostic significance and mechanistic role of microRNA-569 in PC were explored. Quantitative real-time PCR was used to detect the expression of microRNA-569 in PC tissues and cell lines. Scratch test and Transwell assay were conducted to detect migration and invasion ability. The xenograft nude mice model was used to determine tumor metastasis in vivo. The direct targets of microRNA-569 were determined by using bioinformatics analysis and a dual-luciferase reporter assay. The expression level of microRNA-569 was down-regulated in PC patients with a poor prognosis. In vitro and in vivo experiments indicated that over-expression of microRNA-569 inhibited the migration and invasion of PC cells. MicroRNA-569 negatively regulated NUSAP1 by directly binding its 3'-untranslated region. Further mechanism research implied that the ZEB1 pathway was involved in microRNA-569/NUSAP1 mediation of the biological behaviors in PC. These data demonstrated that microRNA-569 may exert a tumor-suppressing effect in PC and maybe a potential therapeutic target for PC patients.