Reduced TRIM expression correlates with anomalous CD4 T cell activation in systemic lupus Erythematosus and its clinical diagnostic potential.

OBJECTIVE: This study seeks to elucidate the expression, function, and clinical relevance of the T cell receptor interacting molecule (TRIM) within circulating CD4+T cell subsets in systemic lupus erythematosus (SLE) patients. METHODS: We assessed TRIM expression across distinct subpopulations of human peripheral blood mononuclear cells (PBMCs) through the analysis of publicly available single-cell RNA sequencing data. In addition, TRIM expression was investigated within CD4+T cell subsets of peripheral blood and spleens in mice. PBMCs were isolated from both SLE patients, healthy controls (HCs) and rheumatoid arthritis (RA) patients with subsequent measurement and comparative analysis of TRIM expression and functional molecules using flow cytometry. To gauge the clinical relevance of TRIM in SLE, correlation and ROC curve analyses were performed. RESULTS: In both healthy humans and mice, TRIM was higher expressed within CD4+T cell subsets, especially in naive CD4+T cells. TRIM+ Tregs exhibited lower Helios+ cells and CD45RA-FoxP3hi cells percentages compared to TRIM- Treg cells. TRIM+T cells demonstrated reduced granzyme B and perforin secretion and increased IFN-γ secretion in comparison to TRIM- T cells. Notably, the proportion of TRIM+CD4+T cells was diminished in SLE patients. The downregulation of TRIM+ in CD4+T cells positively correlated with diminished complement C3 and C1q levels and inversely correlated with CRP. The identification of TRIM-associated CD4 T cell subsets aids in distinguishing SLE patients from HCs and those with RA. CONCLUSIONS: Reduced TRIM expression is linked to abnormal CD4+T cell activation in SLE. TRIM-associated CD4+T cells may be implicated in the pathogenesis of SLE and hold potential for clinical diagnostic purposes.

Studies on absorption mechanism and pharmacokinetic properties of albendazole-bile acid conjugate: In vivo and in vitro.

PURPOSE: To improve the oral bioavailability of albendazole (ABZ), a series of albendazole-bile acid conjugates (ABCs) were synthesized. ABC's transmembrane transport mechanism and in vivo pharmacokinetic properties were preliminarily studied. METHODS: The transmembrane transport mechanism of ABCs was studied using the Caco-2 monolayer cell model and intestinal perfusion model. The concentration of ABCs and ABZ were evaluated using High-Performance Liquid Chromatography (HPLC) and HPLC-Mass Spectrometry (HPLC-MS/MS). RESULTS: Compared to ABZ, better permeability was observed for different types and concentrations of ABCs using the Caco-2 monolayer cell model, with ABC-C8 showing the highest permeability. The transmembrane transport of ABCs was affected by ASBT inhibitors, indicating an ASBT-mediated active transport mechanism. Additionally, introducing cholic acid resulted in ABZ no longer being a substrate for P-gp, MRP2, and BCRP, effectively reversing ABZ efflux. In vivo unidirectional intestinal perfusion results in rats showed that ABCs altered the absorption site of ABZ from the jejunum to the ileum. The absorption efficiency of ABCs in each intestinal segment was higher than that of ABZ, and the transmembrane transport efficiency decreased with increasing concentrations of ASBT inhibitors. This further confirmed the presence of both passive diffusion and ASBT-mediated active transport mechanisms in the transport of ABCs. The solubility of ABCs in gastric juice and pharmacokinetics in rats showed that ABZ-C4 exhibited enhanced solubility. Moreover, ABCs significantly increased oral bioavailability compared to ABZ, with ABC-C4 showing an approximately 31-fold increase in bioavailability. CONCLUSION: The transmembrane transport mechanism of ABCs involves a combination of ASBT-mediated active transport and passive diffusion. Moreover, the incorporation of BAs successfully reverses the efflux of ABZ by efflux proteins. Among the synthesized conjugates, ABC-C4 demonstrated superior dissolution behavior both in vitro and in vivo.

Long-term changes in transmembrane voltage after electroporation are governed by the interplay between nonselective leak current and ion channel activation.

Electroporation causes a temporal increase in cell membrane permeability and leads to prolonged changes in transmembrane voltage (TMV) in both excitable and non-excitable cells. However, the mechanisms of these TMV changes remain to be fully elucidated. To this end, we monitored TMV over 30 min after exposing two different cell lines to a single 100 µs electroporation pulse using the FLIPR Membrane Potential dye. In CHO-K1 cells, which express very low levels of endogenous ion channels, membrane depolarization following pulse exposure could be explained by nonselective leak current, which persists until the membrane reseals, enabling the cells to recover their resting TMV. In U-87 MG cells, which express many different ion channels, we unexpectedly observed membrane hyperpolarization following the initial depolarization phase, but only at 33 °C and not at 25 °C. We developed a theoretical model, supported by experiments with ion channel inhibitors, which indicated that hyperpolarization could largely be attributed to the activation of calcium-activated potassium channels. Ion channel activation, coupled with changes in TMV and intracellular calcium, participates in various physiological processes, including cell proliferation, differentiation, migration, and apoptosis. Therefore, our study suggests that ion channels could present a potential target for influencing the biological response after electroporation.

Metabolic Alkalosis Treatment Standard.

The kidney is poised to defend against development of metabolic alkalosis through non-adaptive mechanisms in the proximal nephron and adaptive processes in the distal nephron. Despite a prodigious capacity to excrete base, metabolic alkalosis is the most common acid-base disturbance in hospitalized patients. Development of this disorder requires pathophysiologic changes leading to generation of new HCO3- combined with an augmentation in the capacity of the kidney to reclaim filtered HCO3-. The initial approach to these patients is careful assessment of effective arterial blood volume focusing on the physical examination and urine electrolytes. Identifying the mechanisms by which the kidney's ability to correct alkalosis are perturbed provides an understanding of the clinical approach to differential diagnosis and appropriate treatment. While metabolic alkalosis is frequently not dangerous, in certain settings, metabolic alkalosis may contribute to mortality and should be aggressively managed.

Subcellular compartmentalized localization of transmembrane proteins essential for production of fungal cyclic peptide cyclochlorotine.

Fungal biosynthetic gene clusters often include genes encoding transmembrane proteins, which have been mostly thought to be transporters exporting the products. However, there is little knowledge about subcellular compartmentalization of transmembrane proteins essential for biosynthesis. Fungal mycotoxin cyclochlorotine is synthesized by non-ribosomal peptide synthetase, which is followed by modifications with three transmembrane UstYa-family proteins. Heterologous expression in Aspergillus oryzae revealed that total biosynthesis of cyclochlorotine requires additional two transporter proteins. Here, we investigated subcellular localizations of the five transmembrane proteins under heterologous expression in A. oryzae. Enhanced green fluorescent protein (EGFP) fusions to the transmembrane proteins, which were confirmed to normally function in cyclochlorotine production, were expressed together with organellar markers. All the transmembrane proteins exhibited localizations commonly in line of the trans-Golgi, endosomes, and vacuoles. This study suggests that subcellular compartmentalization of UstYa family proteins and transporters allows corporative functions of delivering intermediates and subsequent modifications, completing cyclochlorotine biosynthesis.

Transmembrane serine protease 4 expression in the prognosis of radical resection for biliary tract cancer.

BACKGROUND: Recent advancements in biliary tract cancer (BTC) treatment have expanded beyond surgery to include adjuvant therapy, yet the prognosis remains poor. Identifying prognostic biomarkers could enhance the assessment of patients who have undergone radical resection for BTC. AIM: To determine transmembrane serine protease 4 (TMPRSS4) utility as a prognostic biomarker of radical resection for BTC. METHODS: Medical records of patients who underwent radical resection for BTC, excluding intrahepatic cholangiocarcinoma, were retrospectively reviewed. The associations between TMPRSS4 expression and clinicopathological factors, overall survival, and recurrence-free survival were analyzed. RESULTS: Among the 85 patients undergoing radical resection for BTC, 46 (54%) were TMPRSS4-positive. The TMPRSS4-positive group exhibited significantly higher preoperative carbohydrate antigen 19-9 (CA19-9) values and greater lymphatic invasion than the TMPRSS4-negative group (P = 0.019 and 0.039, respectively). Postoperative overall survival and recurrence-free survival were significantly worse in the TMPRSS4-positive group (median survival time: 25.3 months vs not reached, P < 0.001; median survival time: 28.7 months vs not reached, P = 0.043, respectively). Multivariate overall survival analysis indicated TMPRSS4 positivity, pT3/T4, and resection status R1 were independently associated with poor prognosis (P = 0.032, 0.035 and 0.030, respectively). TMPRSS4 positivity correlated with preoperative CA19-9 values ≥ 37 U/mL and pathological tumor size ≥ 30 mm (P = 0.016 and 0.038, respectively). CONCLUSION: TMPRSS4 is a potential prognostic biomarker of radical resection for BTC.

EMP3: A promising biomarker for tumor prognosis and targeted cancer therapy.

Epithelial membrane protein 3 (EMP3) belongs to the peripheral myelin protein 22 kDa (PMP22) gene family, characterized by four transmembrane domains and widespread expression across various human tissues and organs. Other members of the PMP22 family, including EMP1, EMP2, and PMP22, have been linked to various cancers, such as glioblastoma, laryngeal cancer, nasopharyngeal cancer, gastric cancer, breast cancer, and endometrial cancer. However, few studies report on the function and relevance of EMP3 in tumorigenicity. Given the significant structural similarities among members of the PMP22 family, there are likely potential functional similarities as well. Previous studies have established the regulatory role of EMP3 in immune cells like T cells and macrophages. Additionally, EMP3 is found to be involved in critical signaling pathways, including HER-2/PI3K/Akt, MAPK/ERK, and TGF-beta/Smad. Furthermore, EMP3 is associated with cell cycle regulation, cellular proliferation, and apoptosis. Hence, it is likely that EMP3 participates in cancer development through these aforementioned pathways and mechanisms. This review aims to systematically examine and summarize the structure and function of EMP3 and its association to various cancers. EMP3 is expected to emerge as a significant biological marker for tumor prognosis and a potential target in cancer therapeutics.

G-quadruplex-Based Artificial Transmembrane Channels Induce Cancer Cell Apoptosis by Perturbing Potassium Ion Homeostasis.

Transmembrane ion transport modality has received a widespread attention due to its apoptotic activation toward anticancer cell activities. In this study, G-quadruplex-based potassium-specific transmembrane channels have been developed to facilitate the intracellular K+ efflux, which perturbs the cellular ion homeostasis thereby inducing cancer cell apoptosis. Cholesterol-tag, a lipophilic anchor moiety, serves as a rudiment for the G-quadruplex immobilization onto the membrane, while G-quadruplex channel structure as a transport module permits ion binding and migration along the channels. A c-Myc sequence tagged with two-cholesterol is designed as a representative lipophilic G-quadruplex, which forms intramolecular parallel G-quadruplex with three stacks of G-quartets (Ch2-Para3). Fluorescence transport assay demonstrates Ch2-Para3 a high transport activity (EC50 = 10.9 × 10-6 m) and an ion selectivity (K+/Na+ selectivity ratio of 84). Ch2-Para3 mediated K+ efflux in cancer cells is revealed to purge cancer cells through K+ efflux-mediated cell apoptosis, which is confirmed by monitoring the changes in membrane potential of mitochondria, leakage of cytochrome c, reactive oxygen species yield, as well as activation of a family of caspases. The lipophilic G-quadruplex exhibits obvious antitumor activity in vivo without systemic toxicity. This study provides a functional scheme aimed at generating DNA-based selective artificial membrane channels for the purpose of regulating cellular processes and inducing cell apoptosis, which shows a great promising for anticancer therapy in the future.

The updated relationship between the cleft­lip and palate transmembrane protein­1­like rs401681 and lung cancer risk: A systematic review and meta­analysis.

Currently, the role of cleft-lip and palate transmembrane protein-1-like (CLPTM1L) rs401681 in various tumor types, particularly lung cancer, has garnered significant attention. However, the findings across studies have shown discrepancies. The aim of the present meta-analysis was to provide a more nuanced understanding of the involvement of CLPTM1L rs401681 in lung cancer development. Several electronic databases were systematically searched, including PubMed, Cochrane Library, Embase, Medline, Wanfang, Google Scholar and Chinese National Knowledge Infrastructure. Odds ratios (ORs) and 95% confidence intervals (CIs) were synthesized using random-effects models. Heterogeneity of included studies was assessed using the I2 statistic and Q test. Sensitivity analysis was conducted to evaluate the stability of overall estimates. Moreover, Egger's test was utilized to detect potential publication bias. The collective ORs indicated a significant association between the CLPTM1L rs401681 polymorphism and susceptibility to lung cancer across various genetic comparisons. These encompass allele T vs. allele C (OR=0.93, 95% CI=0.88-0.99, P<0.001), TT + CT vs. CC (OR=0.91, 95% CI=0.87-0.96, P<0.001), TT vs. CC + CT (OR=0.88, 95% CI=0.80-0.96, P<0.001), TT vs. CC (OR=0.84, 95% CI=0.75-0.94, P<0.001) and CT vs. CC (OR=0.84, 95% CI=0.75-0.94, P<0.001). Examination through statistical Q test and I2 statistic revealed pronounced heterogeneity across four genetic comparisons (allele T vs. allele C, TT + CT vs. CC, TT vs. CC and CT vs. CC). Ethnical distinctions emerged as the primary, if not exclusive, sources of the significant heterogeneity. Upon stratification by ethnicity, a notable reduction in heterogeneity was discernible within the Caucasian demographic. However, heterogeneity persisted within the Asian population. Furthermore, lung cancer risks were statistically significantly decreased for individuals possessing allele T through all genetic comparisons within Caucasians; whereas among Asians, significant reduction was observed solely in the TT vs. CC comparison. The present meta-analysis uncovers a significant association between the CLPTM1L rs401681 polymorphism and altered susceptibility to lung cancer.

Deep mutational scanning reveals transmembrane features governing surface expression of the B cell antigen receptor.

B cells surveil the body for foreign matter using their surface-expressed B cell antigen receptor (BCR), a tetrameric complex comprising a membrane-tethered antibody (mIg) that binds antigens and a signaling dimer (CD79AB) that conveys this interaction to the B cell. Recent cryogenic electron microscopy (cryo-EM) structures of IgM and IgG isotype BCRs provide the first complete views of their architecture, revealing that the largest interaction surfaces between the mIg and CD79AB are in their transmembrane domains (TMDs). These structures support decades of biochemical work interrogating the requirements for assembly of a functional BCR and provide the basis for explaining the effects of mutations. Here we report a focused saturating mutagenesis to comprehensively characterize the nature of the interactions in the mIg TMD that are required for BCR surface expression. We examined the effects of 600 single-amino-acid changes simultaneously in a pooled competition assay and quantified their effects by next-generation sequencing. Our deep mutational scanning results reflect a feature-rich TMD sequence, with some positions completely intolerant to mutation and others requiring specific biochemical properties such as charge, polarity or hydrophobicity, emphasizing the high value of saturating mutagenesis over, for example, alanine scanning. The data agree closely with published mutagenesis and the cryo-EM structures, while also highlighting several positions and surfaces that have not previously been characterized or have effects that are difficult to rationalize purely based on structure. This unbiased and complete mutagenesis dataset serves as a reference and framework for informed hypothesis testing, design of therapeutics to regulate BCR surface expression and to annotate patient mutations.

PM2.5 Exposure Inhibits Transepithelial Anion Short-circuit Current by Downregulating P2Y2 Receptor/CFTR Pathway.

Fine particulate matter (PM2.5) can damage airway epithelial barriers. The anion transport system plays a crucial role in airway epithelial barriers. However, the detrimental effect and mechanism of PM2.5 on the anion transport system are still unclear. In this study, airway epithelial cells and ovalbumin (OVA)-induced asthmatic mice were used. In transwell model, the adenosine triphosphate (ATP)-induced transepithelial anion short-circuit current (Isc) and airway surface liquid (ASL) significantly decreased after PM2.5 exposure. In addition, PM2.5 exposure decreased the expression levels of P2Y2R, CFTR and cytoplasmic free-calcium, but ATP can increase the expressions of these proteins. PM2.5 exposure increased the levels of Th2-related cytokines of bronchoalveolar lavage fluid, lung inflammation, collagen deposition and hyperplasisa of goblet cells. Interestingly, the administration of ATP showed an inhibitory effect on lung inflammation induced by PM2.5. Together, our study reveals that PM2.5 impairs the ATP-induced transepithelial anion Isc through downregulating P2Y2R/CFTR pathway, and this process may participate in aggravating airway hyperresponsiveness and airway inflammation. These findings may provide important insights on PM2.5-mediated airway epithelial injury.

Enhancing the membrane bioreactor efficiency: The impact of rotating membrane modules and aeration strategies on the transmembrane pressure.

The study analyses the performance of a pilot plant using a rotating hollow fibre (HF) membrane bioreactor system. The experiments evaluated the effect of operational parameters such as rotational speed, aeration strategies, and maintenance cleaning (MC) procedures on the efficiency of the system, in particular transmembrane pressure (TMP) and filtrate quality. The results indicate that the rotating membrane module reduces TMP increase and can operate for 48 days with satisfactory performance, even without aeration. This has the potential to significantly improve efficiency, resulting in significant energy savings. In addition, two MC methods, clean in air and clean in place, were tested and found to be efficient for weekly MC. It was observed that operating without aeration during colder seasons may not be effective. Therefore, adaptive strategies are needed to address seasonal temperature variations.

Synergistic intravesical instillation for bladder cancer: CRISPR-Cas13a and fenbendazole combination therapy.

BACKGROUND: CRISPR-Cas13a is renowned for its precise and potent RNA editing capabilities in cancer therapy. While various material systems have demonstrated efficacy in supporting CRISPR-Cas13a to execute cellular functions in vitro efficiently and specifically, the development of CRISPR-Cas13a-based therapeutic agents for intravesical instillation in bladder cancer (BCa) remains unexplored. METHODS: In this study, we introduce a CRISPR-Cas13a nanoplatform, which effectively inhibits PDL1 expression following intravesical instillation. This system utilizes a fusion protein CAST, created through the genetic fusion of CRISPR-Cas13 and the transmembrane peptide TAT. CAST acts as a potent transmembrane RNA editor and is assembled with the transepithelial delivery carrier fluorinated chitosan (FCS). Upon intravesical administration into the bladder, the CAST-crRNAa/FCS nanoparticles (NPs) exhibit remarkable transepithelial capabilities, significantly suppressing PDL1 expression in tumor tissues.To augment immune activation within the tumor microenvironment, we integrated a fenbendazole (FBZ) intravesical system (FBZ@BSA/FCS NPs). This system is formulated through BSA encapsulation followed by FCS coating, positioning FBZ as a powerful chemo-immunological agent. RESULTS: In an orthotropic BCa model, the FBZ@BSA/FCS NPs demonstrated pronounced tumor cell apoptosis, synergistically reduced PDL1 expression, and restructured the immune microenvironment. This culminated in an enhanced synergistic intravesical instillation approach for BCa. Consequently, our study unveils a novel RNA editor nanoagent formulation and proposes a potential synergistic therapeutic strategy. This approach significantly bolsters therapeutic efficacy, holding promise for the clinical translation of CRISPR-Cas13-based cancer perfusion treatments.

The P2X7 receptor mediates NADPH transport across the plasma membrane.

Nicotinamide Adenine Dinucleotide Phosphate (NADPH) plays a vital role in regulating redox homeostasis and reductive biosynthesis. However, if exogenous NADPH can be transported across the plasma membrane has remained elusive. In this study, we present evidence supporting that NADPH can traverse the plasma membranes of cells through a mechanism mediated by the P2X7 receptor (P2X7R). Notably, we observed an augmentation of intracellular NADPH levels in cultured microglia upon exogenous NADPH supplementation in the presence of ATP. The P2X7R-mediated transmembrane transportation of NADPH was validated with P2X7R antagonists, including OX-ATP, BBG, and A-438079, or through P2X7 knockdown, which impeded NADPH transportation into cells. Conversely, overexpression of P2X7 resulted in an enhanced capacity for NADPH transport. Furthermore, transfection of hP2X7 demonstrated the ability to complement NADPH uptake in native HEK293 cells. Our findings provide evidence for the first time that NADPH is transported across the plasma membrane via a P2X7R-mediated pathway. Additionally, we propose an innovative avenue for modulating intracellular NADPH levels. This discovery holds promise for advancing our understanding of the role of NADPH in redox homeostasis and neuroinflammation.

MMP-14 Exhibits Greater Expression, Content and Activity Compared to MMP-15 in Human Renal Carcinoma.

Membrane-type metalloproteinases (including MMP-14 and MMP-15) are enzymes involved in the degradation of extracellular matrix components. In cancer, they are involved in processes such as cellular invasion, angiogenesis and metastasis. Therefore, the aim of this study was to evaluate the expression, content and activity of MMP-14 and MMP-15 in human renal cell carcinoma. Samples of healthy kidney tissue (n = 20) and tissue from clear-cell kidney cancer (n = 20) were examined. The presence and contents of the MMPs were assessed using Western blot and ELISA techniques, respectively. Their activity-both actual and specific-was evaluated using fluorimetric analysis. Both control and cancer human kidney tissues contain MMP-14 and MMP-15 enzymes in the form of high-molecular-weight complexes. Moreover, these enzymes occur in both active and latent forms. Their content in cancer tissues is very similar, but with a noteworthy decrease in content with an increase in the kidney cancer grade for both membrane-type metalloproteinases. Even more notable is the highest content of the investigated enzymes represented by MMP-14 in the control tissues. Considering the actual and specific activity outcomes, MMP-14 dominates over MMP-15 in all of the investigated tissues. Nevertheless, we also noted a significant enhancement of the activity of both metalloproteinases with an increase in the grade of renal cancer. The expression and activity of both enzymes were detected in all examined renal cancer tissues. However, our findings suggest that transmembrane metalloproteinase 14 (MMP-14) plays a much more significant and essential role than MMP-15 in the studied renal carcinoma tissues. Therefore, it seems that MMP-14 could be a promising target in the diagnosis, prognosis and therapy of renal cell carcinoma.

Characterization of Chemoresistance in Pancreatic Cancer: A Look at MDR-1 Polymorphisms and Expression in Cancer Cells and Patients.

Pancreatic malignancy is the fourth cause of cancer-related death in Western countries and is predicted to become the second leading cause of cancer-related mortality by 2030. The standard therapies (FOLFIRINOX and gemcitabine with nab-paclitaxel) are not resolutive because this type of cancer is also characterized by a high chemoresistance, due in part to the activity of the ATP Binding Cassette (ABC) pumps accounting for the reduction in the intracellular concentration of the drugs. In this work, we analyze the occurrence of single-nucleotide polymorphisms (SNPs) in the MDR-1 gene, in different pancreatic cancer cell lines, and in tissues from pancreatic cancer patients by DNA sequencing, as well as the expression levels of MDR-1 mRNA and protein, by qRT-PCR and Western Blot analysis. We found that gemcitabine-resistant cells, in conjunction with homozygosis of analyzed SNPs, showed high MDR-1 basal levels with further increases after gemcitabine treatment. Nevertheless, we did not observe in the human PDAC samples a correlation between the level of MDR-1 mRNA and protein expression and SNPs. Preliminary, we conclude that in our small cohort, these SNPs cannot be used as molecular markers for predicting the levels of MDR-1 mRNA/protein levels and drug responses in patients with PDAC.

Nanochannel-based biosensor for ultrasensitive and label-free detection of thymidine kinase activity.

Thymidine Kinase 1 (TK1) is a pivotal enzyme in fundamental biochemistry and molecular diagnosis, but recognition and molecule detection is a challenging task. Here, we constructed a DNA-integrated hybrid nanochannel sensor for TK1 activity and inhibition assay. Single-stranded DNA containing thymidine was used as a substrate to functionalize the nanochannels, restricting the ion current through channels. With kinase, the thymidine at the termini of the substrate DNA is phosphorylated, elevating surface charge density and mitigating the pore-obstruction effect by increasing transmembrane ion current. The kinase-induced distinctness can be accurately monitored by this hybrid nanodevice, which benefits from its high sensitivity to the change of surface charge. The excellent analytical performance in both kinase enzyme activity and inhibition analysis resulted in efficient and selective evaluation in human serum. Furthermore, compared to current approaches, it greatly simplifies and offers a direct method of analysis, making it a promising sensor technology for cancer management as well as the activities of multiple types of nucleic acid kinases.

P53 Status Influences the Anti-proliferative Effect Induced by IFITM1 Inhibition in Estrogen Receptor-positive Breast Cancer Cells.

BACKGROUND/AIM: Interferon-induced trans-membrane protein 1 (IFITM1) is known to be involved in breast cancer progression. We aimed to investigate its role in estrogen receptor (ER)-positive breast cancer cells with wild-type p53 and tamoxifen-resistant breast cancer cells. MATERIALS AND METHODS: The ER-positive breast cancer cell lines, MCF-7 with wild-type p53 and T47D with mutant p53, were used. We established an MCF-7-derived tamoxifen-resistant cell line (TamR) by long-term culture of MCF-7 cells with 4-hydroxytamoxifen. RESULTS: IFITM1 inhibition in MCF-7 cells significantly decreased cell growth and migration. MCF-7 cells with suppression of IFITM1 using siRNA or ruxolitinib showed reduced cell viability after tamoxifen treatment compared with that in the control MCF-7 cells. Unexpectedly, mRNA and protein levels of IFITM1 were decreased in TamR cells compared with those in MCF-7 cells. TamR cells with suppression of IFITM1 using siRNA or ruxolitinib showed no change in cell viability after treatment with tamoxifen. P53 knockdown using siRNA reduced the mRNA levels of IRF9 and increased mRNA and protein levels of SOCS3 in MCF-7 cells, suggesting that loss or mutation of p53 can affect the induction of IFITM1 via the JAK/STAT signaling pathway in breast cancer. Furthermore, MCF-7 cells with p53 knockdown using siRNA showed no decrease in cell viability after tamoxifen treatment or IFITM1 inhibition, indicating that p53 status may be important for cell death after tamoxifen treatment or IFITM1 inhibition. CONCLUSION: IFITM1 inhibition may enhance the sensitivity to tamoxifen based on p53-dependent enhancement of IFN signaling in wild-type p53, ER-positive breast cancer cells.

TMEM17 Promotes Tumor Progression in Glioblastoma by Activating the PI3K/AKT Pathway.

BACKGROUND: Glioblastoma (GBM) is a highly aggressive and fast-growing brain tumor, characterized by rapid progression, a very poor prognosis, and a high likelihood of recurrence. Thus, effective new therapeutic targets are urgently needed. Transmembrane proteins (TMEMs) have pro-cancer effects on multiple cancer types, but the mechanisms underlying the effects of TMEM17, particularly its role in GBM, remain unclear. METHODS: We conducted bioinformatics analyses and immunohistochemistry to evaluate the role of TMEM17 in a variety of cancer types. Functional assays were conducted included the Cell Counting Kit-8 assay, annexin V-FITC/PI double staining, 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, wound healing assay, transwell invasion assay, and dual luciferase assay. RESULTS: We found that TMEM17 is associated with a poor prognosis in GBM. Prognostic analyses confirmed that high TMEM17 expression predicted poorer survival, establishing its significance as an independent prognostic factor. Functional assays demonstrated that silencing TMEM17 in GBM cell lines inhibited proliferation and invasion, and induced apoptosis, underscoring its role in tumor aggressiveness. From a mechanistic perspective, we discovered that the Ying Yang 1 (YY1) transcription factor can bind to the promoter of TMEM17, regulating its upregulation. Regarding downstream mechanisms, knocking down TMEM17 inhibited the phosphoinositide 3-kinase/AKT pathway. These findings suggest that TMEM17 plays a significant role in GBM and may be a potential therapeutic target for this cancer. CONCLUSION: These data prove that TMEM17 plays a key role in the regulation of GBM and has great potential as a clinical therapeutic target for GBM.