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Immune checkpoint inhibitors (ICIs) show promise as second‐line treatment for advanced bladder cancer (BLCA); however, their responsiveness is limited by the immune evasion mechanisms in tumor cells. This study conduct a Cox regression analysis to screen mRNA‐binding proteins and reveals an association between Ras GTPase‐activating protein‐binding protein 1 (G3BP1) and diminished effectiveness of ICI therapy in patients with advanced BLCA. Subsequent investigation demonstrates that G3BP1 enhances immune evasion in BLCA cells by downregulating major histocompatibility complex class I (MHC‐I) through phosphoinositide 3‐kinase (PI3K)/Akt signaling activation. Mechanistically, G3BP1 interacts with splicing factor synergistic lethal with U5 snRNA 7 (SLU7) to form a complex with poly(A)‐binding protein cytoplasmic 1 and eukaryotic translation initiation factor 4 gamma 1. This complex stabilizes the closed‐loop structure of the mRNAs of class IA PI3Ks and consequently facilitates their translation and stabilization, thereby activating PI3K/Akt signaling to downregulate MHC‐I. Consistently, targeting G3BP1 with epigallocatechin gallate (EGCG) impedes immune evasion and sensitizes BLCA cells to anti‐programmed cell death (PD)‐1 antibodies in mice. Thus, G3BP1 and SLU7 collaboratively contribute to immune evasion in BLCA, indicating that EGCG is a precision therapeutic agent to enhance the effectiveness of anti‐PD‐1 therapy. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide and is typically treated with the FOLFOX regimen (folinic acid, 5‐fluorouracil, and oxaliplatin). However, oxaliplatin resistance remains a serious clinical problem. In the present study, we found that SUMO2/3 was overexpressed in CRC tissues and exogenous overexpression of SUMO2/3 promoted CRC cell proliferation, extension, and invasion and positively regulated the cell cycle. In contrast, SUMO2/3 gene knockdowns inhibited migration and repressed cell viability in vitro and in vivo. In addition, we found that SUMO2/3 was recruited to the cell nucleus and suppressed oxaliplatin‐induced apoptosis of CRC cells. Moreover, Ku80, a DNA‐binding protein essential for the repair of DNA double‐strand breaks, was confirmed to bind with SUMO2/3. Notably, Ku80 undergoes SUMOylation at K307 by SUMO2/3 and this correlated with apoptosis in CRC cells suffering oxaliplatin stress. Collectively, we found that SUMO2/3 plays a specific role in CRC tumorigenesis and acts through Ku80 SUMOylation which is linked with the development of CRC‐oxaliplatin resistance. [ABSTRACT FROM AUTHOR]

Breast cancer is a major cause of cancer‐related morbidity and mortality in women. Estrogen receptor‐positive breast cancer accounts for roughly 70%‐80% of breast tumors, and estrogen receptor alpha (ERα) has been considered as a key driver in promoting breast cancer progression. In the present study, we identified USP37 as a novel modulator in modulating ERα ubiquitination and stability. The expression of USP37 was upregulated in ERα‐positive breast cancer and correlated with ERα protein level. High expression of USP37 was associated with unfavorable prognosis. USP37 depletion resulted in significantly decreased ERα protein level, ERα target genes expression as well as the estrogen response element activity in breast cancer cells. Further mechanistic study revealed the interaction between USP37 and ERα: USP37 regulated ERα signaling through modulating protein stability instead of gene expression, in which it stabilized ERα protein via inhibiting the K48‐specific polyubiquitination process. Additionally, USP37 depletion led to growth inhibition and cell cycle arrest of ERα‐positive breast cancer cells, which could be further rescued by ERα overexpression. Overall, our study proposed a novel post‐translational mechanism of ERα in promoting breast cancer progression. Targeting USP37 may be proved to be a promising strategy for patients with ERα‐positive breast cancer. [ABSTRACT FROM AUTHOR]

Expansion microscopy (ExM) has been widely used to detect biomolecules in cultured cells and tissue samples due to its enablement of super resolution imaging with conventional microscopes, via physical expansion of samples. However, reaction conditions inherent to the process bring about strong fluorescent signal loss during polymerization and digestion and thus limit the brightness of the signal obtained post expansion. Here, we explore the impact of stabilizer‐containing organic fluorophores in ExM, as a mitigation strategy for this radical‐induced dye degradation. Through direct conjugation of 4‐nitrophenylalanine (NPA) to our previously developed trifunctional reagents, we validate and demonstrate that these multifunctional linkers enable visualization of different organelles with improved fluorescent intensity, owning to protection of the dyes to radical induced degradation as well as to photoprotection upon imaging. At this point, we cannot disentangle the relative contribution of both mechanisms. Furthermore, we report anchoring linkers that allow straightforward application of NPA or Trolox to commercially available fluorophore‐conjugated antibodies. We show that these anchoring linkers enable complete retention of biological targets while increasing fluorophore photostability. Our results provide guidance in exploring these stabilizer‐modified agents in ExM and methods for increased signal survival through the polymerization steps of the ExM protocols. [ABSTRACT FROM AUTHOR]

Enhancers are well established as critical regulators of gene expression, but the mechanisms underlying the molecular basis of their specificity and activity are only partly understood. One of the most exciting recent observations is the discovery of enhancer RNA (eRNA), a class of noncoding RNAs derived from enhancer regions. Transcription of developmentally regulated enhancers has been observed to be associated with their active state. The nature of transcripts (eRNA) and their functional attributes are diverse and context dependent. The majority of eRNA are nonpolyadenylated and present in low abundance owing to their low stability, and may represent transcriptional noise. However, some eRNAs have been reported to be reasonably long and stable, are enriched in nuclei, exhibit tissue‐specific expression and may contribute to enhancer function. Transcription of enhancers has been postulated to mediate enhancer function through either the act of transcription or via the transcribed RNA per se and is a useful feature to be analysed to understand mechanisms underlying enhancer activity. Enhancer Eβ at the murine TCRβ locus has been reported to exhibit enhanced occupancy of RNA polymerase II in developing thymocytes. Here, we investigated the transcriptional potential of Eβ in developing thymocytes and detected overlapping bidirectional transcripts at Eβ ranging between 0.7 and 1.7 kb. These noncoding transcripts are capped, polyadenylated, nuclear and expressed specifically in thymocytes. Delineation of these characteristics is important to further investigate their functional roles in mediating enhancer activity. [ABSTRACT FROM AUTHOR]

It has long been observed that human protein‐coding genes have a particular distribution of GC‐content: the 5′ end of these genes has high GC‐content while the 3′ end has low GC‐content. In 2012, it was proposed that this pattern of GC‐content could act as an mRNA identity feature that would lead to it being better recognized by the cellular machinery to promote its nuclear export. In contrast, junk RNA, which largely lacks this feature, would be retained in the nucleus and targeted for decay. Now two recent papers have provided evidence that GC‐content does promote the nuclear export of many mRNAs in human cells. [ABSTRACT FROM AUTHOR]

In recent years, studies have shown that enhancer RNAs (eRNAs) can be transcribed from enhancers. Increasing evidence has revealed that eRNAs play critical roles in the development of various cancers. Oestrogen‐associated eRNAs are closely related to breast cancer. In view of the gender differences in bladder cancer (BCa), we suppose that oestrogen‐associated eRNAs are also involved in tumorigenesis of BCa. In our study, we first demonstrated that eGREB1 derived from the enhancer of an oestrogen‐responsive gene—GREB1 was up‐regulated in BCa tissues, and the expression level of eGREB1 is positively associated with the histological grade and TNM stage of BCa. Knockdown of eGREB1 by CRISPR‐Cas13a could inhibit cell proliferation, migration and invasion and induce apoptosis in BCa cells T24 and 5637. Besides, we exhibited the promoting effect of oestrogen on BCa cells. What's more, down‐regulation of eGREB1 could improve the malignant biological characteristics of BCa cells induced by oestrogen. In conclusion, our data indicated that eGREB1 plays oncogenic role and oestrogen may promote the occurrence and progression of BCa by inducing eGREB1 production. Our findings provide new insights into the prevention of BCa and develop a novel therapeutic target for the treatment of BCa. [ABSTRACT FROM AUTHOR]

Background: Tamoxifen, a selective estrogen receptor modulator, decreased airway neutrophilia and improved clinical signs in an experimental model of equine asthma, and induced neutrophilic apoptosis in vitro. Hypothesis/Objectives: Tamoxifen reduces airway neutrophilia and improves lung function in severe asthmatic horses. Animals Twelve severe asthmatic horses from a research herd. Methods: Randomized controlled blinded study design. The effects of a 12‐day oral treatment with tamoxifen (0.22 mg/kg, q24h) or dexamethasone (0.06 mg/kg, q24h) on lung function, endoscopic tracheal mucus score and bronchoalveolar lavage fluid cytology were compared. Results: Tamoxifen significantly improved the pulmonary resistance (RL; mean reduction of 1.15 cm H2O/L/s [CI: 0.29‐2.01, P = .007] on day 13), but had no effect on the other variables evaluated. Dexamethasone normalized lung function (mean reduction of RL of 2.48 cm H2O/L/s [CI: 1.54‐3.43, P < .0001] on day 13), without affecting airway neutrophilia. Conclusions and Clinical Importance: Results of this study do not support the use of tamoxifen at the dose studied as an antineutrophilic medication in the treatment of asthmatic horses in chronic exacerbation. [ABSTRACT FROM AUTHOR]

Although extensively studied, themechanismsbywhich estrogenpromotes breast cancer growth remain to be fully elucidated. Tamoxifen, an antiestrogen agent to treat ERα+ breast cancer, is also a high-affinity blocker of the chloride channels. In this study, weexplored the involvement of the chloride channels in the action of estrogen in breast cancer. We found that 17β-estradiol (17β-E2) concentration-dependently activated the chloride currents in ERα+ breast cancerMCF-7 cells. Extracellular hypertonic challenge and chloride channel blockers, NPPB and DIDS inhibited the 17β-E2-activated chloride currents. Decreased the ClC-3 protein expression caused the depletion of the 17β-E2-activated chloride currents. 17β-E2-activated chloride currents which relied on the ERα expression were demonstrated by the following evidences. Firstly, 17β- E2-activated chloride currents could not be observed in ERα- breast cancerMDA-MB-231 cells. Secondly, ER antagonists, tamoxifen and ICI 182,780, and downregulation of ERα expression inhibited or abolished the 17β-E2-activated chloride currents. Thirdly, ERα expression was induced in MDA-MB-231 cells by ESR1 gene transfection, and then 17β-E2-activated chloride currents could be observed. In MCF-7 cells, ERα and ClC-3 mainly located in nucleus and translocated to cell plasma and membrane with respect to co-localization following treatment of 17β-E2. Downregulation of ERα expression could decrease the expression of ClC-3 protein. Conversely, downregulation of ClC-3 expression did not influence the ERα expression. Taken together, our findings demonstrated that ClC-3 is a potential target of 17β-E2 and is modulated by the ERα in breast cancer cell. Pharmacological modulation of ClC-3 may provide a deep understanding in antiestrogen treatment of breast cancer patients. [ABSTRACT FROM AUTHOR]

Cytochrome P450 (CYP) 1A1 plays a major role in the metabolic activation of procarcinogens to carcinogens via aryl hydrocarbon receptor (AhR) pathway. Especially, 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) is known as an agonist of AhR. In estrogen responsive cancers, 17β-estradiol (E2) may influence on AhR dependent expression of CYP1 family via the interaction between estrogen receptor (ER) and AhR. In the present study, the effect of E2/ER on the expression of AhR and CYP1A1 genes was investigated for MCF-7 clonal variant (MCF-7 CV) breast cancer cells expressing ER. In reverse transcription-PCR and Western blot analysis, mRNA expression level of AhR was not altered, but its protein expression level was increased by TCDD or E2. The transcriptional and translational levels of CYP1A1 appeared to be increased by TCDD or E2. The increased expression of AhR and CYP1A1 induced by E2 was restored to the control level by the co-treatment of ICI 182,780, indicating that E2 induced the protein expression levels of AhR and CYP1A1 like TCDD via an ER dependent pathway. In an in vivo xenograft mouse model transplanted with MCF-7 CV cells, the protein expression levels of AhR and CYP1A1 of tumor masses were also increased by E2 or TCDD. Taken together, these results indicate that E2 may promote AhR dependent expression of CYP1A1 via ER dependent pathway in MCF-7 CV cells expressing ER in the absence of TCDD, an agonist of AhR. The relevance of E2 and ER in CYP1A1 activation of estrogen responsive cancers may be targeted for developing more effective cancer treatments. [ABSTRACT FROM AUTHOR]

Single‐cell analysis has recently received significant attention in biomedicine. With the advances in super‐resolution microscopy, fluorescence labeling, and nanoscale biosensing, new information may be obtained for the design of cancer diagnosis and therapeutic interventions. The discovery of cellular heterogeneity further stresses the importance of single‐cell analysis to improve our understanding of disease mechanism and to develop new strategies for disease treatment. To this end, many studies are exploited at the single‐cell level for high throughput, highly parallel, and quantitative analysis. Technically, microfluidics are also designed to facilitate single‐cell isolation and enrichment for downstream detection and manipulation in a robust, sensitive, and automated manner. Further achievements are made possible by consolidating optically label‐free, electrical, and molecular sensing techniques. Moreover, these technologies are coupled with computing algorithms for high throughput and automated quantitative analysis with a short turnaround time. To reflect on how the technological developments have advanced single‐cell analysis, this mini‐review is aimed to offer readers an introduction to single‐cell analysis with a brief historical development and the recent progresses that have enabled multiscale analysis of single‐cells in the last decade. The challenges and future trends are also discussed with the view to inspire forthcoming technical developments. [ABSTRACT FROM AUTHOR]