PTEN Protein Expression Research Articles

MicroRNA-875-5p-conjugated gold nanoparticles suppress breast cancer progression through the MTDH/PTEN/AKT signaling pathway

ObjectiveA lack of effective delivery methods has hampered the study of therapeutics targeting miR-875-5p for breast cancer (BC).MethodsThe miR-875-5p mimic was conjugated to AuNPs to produce AuNP-miR-875-5p. Then, the effect of AuNP-miR-875-5p on the proliferative, migratory, invasive activities, and apoptosis of BC cells was detected, as well as on tumor growth in animals. The involvement of the MTDH/PTEN/AKT pathway in miR-875-5p-mediated BC progression was identified.ResultsAuNP-miR-875-5p was delivered to BC cells and hampered cell malignancy. MTDH was targeted by miR-875-5p. MTDH expression was negatively correlated with miR-875-5p expression in BC tissues. The anti-tumor effect of AuNP-miR-875-5p in BC cells was counteracted by MTDH overexpression. AuNP-miR-875-5p enhanced PTEN protein expression, thereby inhibiting AKT activation by targeting MTDH. AuNP-miR-875-5p blocked MCF-7 tumor growth in vivo.ConclusionAuNPs can deliver miR-875-5p to BC cells, and AuNP-miR-875-5p has clinical potential for treating unresectable BC.

The oncogenic axis YAP/MYC/EZH2 impairs PTEN tumor suppression activity enhancing lung tumorigenicity

The tumor suppressor PTEN (phosphatase and tensin homolog deleted in chromosome 10) is genetically deleted or downregulated in many cancer types. Loss of PTEN protein expression is frequently found in lung cancer while genetic alterations are less abundant. PTEN expression is regulated at multiple genetic and epigenetic levels and even partial reduction of its expression increases cancer occurrence. We show that YAP and TAZ cooperate with EZH2, and MYC to transcriptionally repress onco-suppressor genes, including PTEN, in non-small cell lung cancer (NSCLC) cells. YAP/TAZ-EZH2-MYC transcriptional regulators form a nuclear complex that represses PTEN transcription, while their combinatorial targeting restores PTEN expression, attenuates NSCLC cell growth, and prevents compensatory responses induced by single treatments. Datasets analysis of NSCLC patients revealed that PTEN expression is negatively correlated to YAP/TAZ, EZH2 and MYC and that low expression of PTEN is predictive of poor prognosis, especially at earlier stages of the disease. These findings highlight the repressive role of the YAP/TAZ-EZH2-MYC axis on tumor-suppressor genes and offer a potential therapeutic strategy for lung cancer patients with low PTEN levels.

Dysfunction of PTEN-Associated MicroRNA Regulation: Exploring Potential Pathological Links in Type 1 Diabetes Mellitus.

Background and Objectives: Type 1 Diabetes Mellitus (T1DM) is an autoimmune disease with T cell-mediated pathogenesis of pancreatic β-cell destruction, leading to insulin deficiency. MicroRNAs such as miR-223 and miR-106b, along with PTEN, have been reported to participate in the pathophysiology of diabetes and its complications. The current study has explored the expression of miR-223, miR-106b, and PTEN and their association with various clinical and biochemical parameters in subjects diagnosed with T1DM. Materials and Methods: Sixty T1DM patients (two groups as uncomplicated/ with microalbuminuria) and fifty healthy volunteers, age- and sex-matched, were enrolled in this study. The fasting venous blood samples were collected, and PTEN and miRNAs (miR-223 and miR-106b) levels were measured by ELISA and real-time PCR, respectively. Results: The PTEN levels of patients with microalbuminuria were significantly lower than those of patients without microalbuminuria, while those of miR-223 and miR-106b were significantly increased in the T1DM group compared with the healthy control group (p < 0.001). ROC analysis indicated that PTEN, miR-223, and miR-106b could be potential biomarkers for diagnosing T1DM with high specificity but with variable sensitivities. Also, PTEN and miR-223 were negatively correlated with r =-0.398 and p < 0.0001, indicating that they were interrelated in their role within the T1DM pathophysiology. Conclusions: In the current study, it has been shown that the circulating levels of PTEN, miR-223, and miR-106b are significantly changed in T1DM patients and may back their potential to be used as non-invasive biomarkers for the diagnosis and monitoring of T1DM. Low PTEN protein expression was related to high miR-223 expression, indicating involvement of these miRNA in the regulation of PTEN. Further studies should be performed to clarify the exact mechanisms and possible clinical applications of these molecules.

Anticancer effect of the oncolytic Newcastle disease virus harboring the PTEN gene on glioblastoma.

Glioblastoma (GBM) is one of the most lethal types of human brain cancer and is characterized by rapid growth, an aggressive nature and a poor prognosis. GBM is highly heterogeneous, and often involves several genetic mutations and abnormalities. Genetic disorders or low expression of phosphatase and tensin homolog (PTEN) are associated with GBM occurrence, progression and poor prognosis of patients with GBM. However, effective delivery of PTEN for expression in GBM cells within the brain remains challenging. The aim of the present study was to develop a therapeutic strategy to restore PTEN expression in GBM cells by utilizing a recombinant Newcastle disease virus (rNDV) vector expressing the human PTEN gene (rNDV-PTEN). Methods included infection of U87-MG cells with rNDV-PTEN, followed by assessments of PTEN expression, and cell proliferation, migration and apoptosis. Additionally, an orthotopic GBM mouse model was used to evaluate the in vivo efficacy of rNDV-PTEN. Infection with recombinant rNDV-PTEN treatment increased PTEN protein expression in the cytoplasm of the U87-MG cells, reduced cell proliferation and migration, and induced apoptosis by inhibiting the AKT/mTOR signaling pathway. In the orthotopic GBM mouse model, rNDV-PTEN significantly reduced tumor size and improved survival rates. Magnetic resonance imaging and in vivo imaging analyses confirmed the targeted delivery and efficacy of rNDV-PTEN. These findings highlight the usefulness of rNDV-PTEN as a promising therapeutic agent for GBM, representing a potential advancement in treatment, especially for patients with PTEN deficiency.

Regulation of Curcumin on Follicle Initiation Rate in Diminished Ovarian Reserve.

To study the mechanism by which curcumin regulates ovarian primordial follicle initiation in rats with triptolide-induced diminished ovarian reserve (DOR). An in vitro gelatin sponge culture was performed on 3-day-old rat ovaries. After the establishment of the DOR model with triptolide, curcumin was administered for 3 days. Histological analysis and follicle counts were performed using H&E staining. ELISA detection of ovarian hormones in the culture medium (E2, FSH and LH), western blotting and Q-PCR for protein and mRNA expression (LTCONS-00011173, TGF-β1, Smad1, AMH, PTEN and GDF-9). Ovarian primordial and growing follicles increased significantly after curcumin intervention (p < 0.05), FSH/LH and E2 levels were increased significantly (p < 0.05). Curcumin also significantly decreased the expression of LTCONS-00011173. Meanwhile, curcumin increased the expression of TGF-β, AMH, and GDF-9 (p < 0.05). In addition, curcumin increased Smad1 gene expression and protein phosphorylation in the ovary on the one hand (p < 0.05), but inhibited Smad1 and p-Smad1 protein expression on the other hand (p < 0.05). Moreover, curcumin decreased PTEN protein and mRNA expression (p < 0.05). Curcumin activates primordial follicles in DOR model rats through TGF-β1 and downstream AMH signaling pathways and may limit follicle exhaustion through LncRNA.

Shisandra Decoction Alleviates Parkinson's Disease Symptoms in a Mouse Model Through PI3K/AKT/mTOR Signalling Pathway.

The present study aimed to characterize neuroprotective effects of Schisandra Decoction (Sch D) treatment in a mouse model of Parkinson's disease (PD), and to explore underlying mechanisms focused on the mammalian target of rapamycin (mTOR) signaling pathway. 50 male C57 BL/6 mice were randomly assigned to either control (n = 10) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model (n = 40) groups. PD mice were further divided into four groups of ten mice each: MPTP group, LY294002 group, Sch D group, and LY2940002 + Sch D group. Mice from each group were assessed in pole climbing, rotary rod and open field tests. Brain Tyrosine hydroxylase (TH) protein was observed using immunohistochemistry. mRNA levels of PTEN, PI3K and LC3 in brain tissue were measured using RT-PCR. Protein levels of PTEN, PI3K, Akt, p-Akt, mTOR, p-mTOR, p70s6K, p62, LC3II / I, α-synuclein (α-syn), TH in brain tissue were assessed by Western blotting (WB). In behavioral tests, PD mice treated with Sch D showed reduced pole climbing time, longer rotarod duration, and greater distance traveled. In terms of neuroprotection, PD mice in the Sch D group exhibited higher levels of TH protein and enhanced α-syn clearance. Regarding autophagy, compared to the control group, mice in the MPTP group had elevated PTEN protein expression, which inhibited PI3K, p-AKT/AKT, and p-mTOR/mTOR protein levels, decreased LC3II/I protein expression, and increased P62 protein expression. Treatment with Sch D reversed these effects. Sch D reduces α-syn aggregation in the brains of MPTP-induced PD model mice, exerts neuroprotective effects, and improves motor function. Additionally, Sch D inhibits autophagy through the PI3K/AKT/mTOR pathway. The neuroprotective effect of Sch D may involve the suppression of abnormal autophagy and its antioxidant properties, which indirectly reduces α-syn accumulation. Future studies should assess the impact of Sch D on oxidative stress markers to evaluate its antioxidant effects.

The cellular signaling and regulatory role of protein phosphatase in tumor diagnosis: Upstream miRNAs of PTEN

Protein phosphatases have demonstrated considerable promise in the realm of early tumor diagnosis across various malignancies. These enzymes play a critical role in modulating the PI3K-Akt signaling pathway, which is integral to cellular processes such as proliferation, survival, and migration. When the activity of protein phosphatases becomes abnormal, it can disrupt these essential signaling pathways, potentially leading to the initiation and progression of tumors. Consequently, monitoring for abnormal expression and activity levels of protein phosphatases could serve as a vital biomarker for early cancer detection. By identifying these alterations, clinicians may be better equipped to diagnose tumors at an earlier stage, significantly improving patient outcomes.In summary, our study highlights the multifaceted and significant role of PTEN in various forms of cancer, including esophageal squamous cell carcinoma (ESCA). Further analysis showed that the expression levels of protein phosphatase and PTEN protein were significantly associated with the early diagnosis of tumors, especially in the early stage of tumors, and their detection sensitivity and specificity were high. Therefore, by detecting the expression of protein phosphatase and PTEN protein, the early diagnosis of tumor can be achieved, and the therapeutic effect and prognosis of patients can be improved.

Placental mesenchymal stem cell exosome-derived miR-139-5p regulates PTEN gene and influences chemotherapeutic-induced ovarian dysfunction

Objective: To investigate the impact of exosomes and microRNA (miRNA) from placental mesenchymal stem cells on chemotherapy-damaged ovarian granulosa cells. Methods: Various public databases were searched for miRNA targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN) gene. After miRNA transfection into human ovarian granulosa cells, cell growth and expressions of the target miRNA and PTEN were detected. Cisplatin was utilized to induce damage to human ovarian granulosa cells, which were subsequently co-cultured with human placental mesenchymal stem cells and exosomes generated from mesenchymal stem cells, then apoptosis and expressions of PTEN and the target miRNA were detected. Results: After analyzing several databases, miRNA 139-5p (miR-139-5p) was chosen as the target miRNA for this research. Transfection of miR-139-5p mimics into human ovarian granulosa cells elevated miR-139-5p expression level (9 882.080±1 049.130), reduced PTEN protein expression level (0.78±0.11), and increased cell proliferation absorbance (0.85±0.07). Cisplatin treatment severely damaged human ovarian granulosa cells and increased apoptosis, cisplatin-treated cells had a higher apoptosis ratio compared to untreated cells [ (41.9±1.0)% vs (5.0±0.3)%, P<0.001]. In damaged human ovarian granulosa cells, co-cultured with human placental mesenchymal stem cells and exosomes increased miR-139-5p expression levels (1.31±0.04 and 1.20±0.03, respectively) and decreased apoptosis ratios [(20.0±0.4)% and (22.3±1.1)%, respectively]. Conclusion: Placental mesenchymal stem cell-derived exosomes repair damages of cisplatin-induced ovarian granulosa cell and could target PTEN gene through miR-139-5p, which might be a potential option for the treatment of chemotherapy-induced ovarian dysfunction.

Prognostic Importance of PTEN, p53, and MDM2 Expressions in Endometrioid and Serous-Type Endometrial Carcinomas

Aim: Endometrial carcinomas (ECs) are neoplasms with the highest rate of change in the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway. In this study, the relationship among PTEN, MDM2, and p53 protein expression in the PI3K/AKT/mTOR pathway with clinicopathological data in endometrioid endometrial carcinomas (EECs) and serous-type endometrial carcinomas (SECs) was evaluated. Material and Method: A hundred and twenty cases of patients who underwent hysterectomy for EC between 2009 and 2021 were included in the study. Thirty cases of SEC and 90 cases of EEC were evaluated. EEC cases consist of grades 1-3 tumors, and each group includes 30 patients. p53 was examined in two groups as normal/wild type and abnormal/mutant type. PTEN and MDM2 were examined in two groups: positive and negative. The relationship among p53, PTEN, and MDM2 immunohistochemical expression status with histological grade, myometrial invasion, cervical invasion, lymphovascular invasion (LVI), metastatic lymph nodes, presence of tumor in peritoneal fluid, tumor stage, and overall and progression-free survival was evaluated. Results: Loss of PTEN was associated with EEC compared to SEC (p

Huangqin Qingrechubi Capsule alleviates inflammation and uric acid and lipid metabolism imbalance in rats with gouty arthritis by inhibiting the PTEN/PI3K/AKT signaling pathway

To investigate the effects of Huangqin Qingrechubi Capsule (HQC) on inflammation and uric acid and lipid metabolism in rats with gouty arthritis (GA) and its mechanism. SD rat models of GA established by injecting monosodium urate into the right ankle joint were treated with saline, colchicine and HQC at low, medium and high doses (n=10) by gavage for 7 days. Toe swelling of the rats was detected at 4, 8, 24, 48 and 72 h after modeling, and synovial histological changes were observed with HE staining. Serum levels of interleukin-10 (IL-10), IL-18, tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), adiponectin, leptin, resistin and visfatin were measured by ELISA, and the levels of high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), total cholesterol (TC), and uric acid (BUA) were detected. RTqPCR and Western blotting were used to detect the mRNA expressions of phosphatase and tensin homolog (PTEN), phosphatidylinositol-3-kinase (PI3K) and protein kinase B (AKT) and the protein expressions of PTEN, PI3K, p-PI3K, AKT and p-AKT. The rat models of GA showed obvious toe swelling, which reached the peak level at 48 h. HE staining revealed massive inflammatory cell infiltration and synovial tissue hyperplasia. The rat models showed significantly increased expressions of TNF-α, TGF-β1, IL-18, TC, TG, leptin, resistin and visfatin, BUA, p-PI3K, and p-AKT and lowered levels of IL-10, APN, HDL-C, and PTEN. Treatment with HQC and colchicine obviously improved these changes and alleviated synovial pathologies and toe swelling in the rat models. HQC can improve inflammation and correct the imbalance of uric acid and lipid metabolism in GA rats possibly by inhibiting the PTEN/PI3K/AKT signaling pathway.

Genome-wide CRISPR screening identifies critical role of phosphatase and tensin homologous (PTEN) in sensitivity of acute myeloid leukemia to chemotherapy.

Although significant progress has been made in the development of novel targeted drugs for the treatment of acute myeloid leukemia (AML) in recent years, chemotherapy still remains the mainstay of treatment and the overall survival is poor in most patients. Here, we demonstrated the antileukemia activity of a novel small molecular compound NL101, which is formed through the modification on bendamustine with a suberanilohydroxamic acid (SAHA) radical. NL101 suppresses the proliferation of myeloid malignancy cells and primary AML cells. It induces DNA damage and caspase 3-mediated apoptosis. A genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) library screen revealed that phosphatase and tensin homologous (PTEN) gene is critical for the regulation of cell survival upon NL101 treatment. The knockout or inhibition of PTEN significantly reduced NL101-induced apoptosis in AML and myelodysplastic syndrome (MDS) cells, accompanied by the activation of protein kinase B (AKT) signaling pathway. The inhibition of mammalian target of rapamycin (mTOR) by rapamycin enhanced the sensitivity of AML cells to NL101-induced cell death. These findings uncover PTEN protein expression as a major determinant of chemosensitivity to NL101 and provide a novel strategy to treat AML with the combination of NL101 and rapamycin.

RBM5 suppresses proliferation, metastasis and glycolysis of colorectal cancer cells via stabilizing phosphatase and tensin homolog mRNA.

RNA binding motif 5 (RBM5) has emerged as crucial regulators in many cancers. To explore more functional and mechanistic exploration of RBM5 since the lack of research on RBM5 in colorectal cancer (CRC) dictates that is essential. Through Gene Expression Profiling Interactive Analysis, we analyzed RBM5 expression in colon adenocarcinoma and rectum adenocarcinoma tissues. For detecting the mRNA expression of RBM5, quantitative real time-polymerase chain reaction was performed. Protein expression levels of RBM5, hexokinase 2, lactate dehydrogenase A, phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), phosphorylated-protein kinase B (p-AKT), and AKT were determined via Western blot. Functionally, cell counting kit-8 and 5-ethynyl-2'-deoxyuridine (EDU) assay were performed to evaluate proliferation of CRC cells. Invasiveness and migration of CRC cells were evaluated through conducting transwell assays. Glucose consumption, lactate production and adenosine-triphosphate (ATP) production were measured through a glucose assay kit, a lactate assay kit and an ATP production assay kit, respectively. Besides, RNA immunoprecipitation assay, half-life RT-PCR and dual-luciferase reporter assay were applied to detect interaction between RBM5 and PTEN. To establish a xenotypic tumor mice, CRC cells were subcutaneously injected into the right flank of each mouse. Protein expression of RBM5, Ki67, and PTEN in tumor tissues was examined using immunohistochemistry staining. Haematoxylin and eosin staining was used to evaluate tumor liver metastasis in mice. We discovered down-regulation of RBM5 expression in CRC tissues and cells. RBM5 overexpression repressed proliferation, migration and invasion of CRC cells. Meantime, RBM5 impaired glycolysis in CRC cells, presenting as decreased glucose consumption, decreased lactate production and decreased ATP production. Besides, RBM5 bound to PTEN mRNA to stabilize its expression. PTEN expression was positively regulated by RBM5 in CRC cells. The protein levels of PI3K and p-AKT were significantly decreased after RBM5 overexpression. The suppressive influences of RBM5 on glycolysis, proliferation and metastasis of CRC cells were partially counteracted by PTEN knockdown. RBM5 suppressed tumor growth and liver metastasis in vivo. This investigation provided new evidence that RBM5 was involved in CRC by binding to PTEN, expanding the importance of RBM5 in the treatment of CRC.

DNA ploidy and PTEN as biomarkers for predicting aggressive disease in prostate cancer patients under active surveillance

BackgroundCurrent risk stratification tools for prostate cancer patients under active surveillance (AS) may inadequately identify those needing treatment. We investigated DNA ploidy and PTEN as potential biomarkers to predict aggressive disease in AS patients.MethodsWe assessed DNA ploidy by image cytometry and PTEN protein expression by immunohistochemistry in 3197 tumour-containing tissue blocks from 558 patients followed in AS at a Norwegian local hospital. The primary endpoint was treatment, with treatment failure (biochemical recurrence or initiation of salvage therapy) as the secondary endpoint.ResultsThe combined DNA ploidy and PTEN (DPP) status at diagnosis was associated with treatment-free survival in univariable- and multivariable analysis, with a HR for DPP-aberrant vs. DPP-normal tumours of 2.12 (p < 0.0001) and 1.94 (p < 0.0001), respectively. Integration of DNA ploidy and PTEN status with the Cancer of the Prostate Risk Assessment (CAPRA) score improved risk stratification (c-index difference = 0.025; p = 0.0033). Among the treated patients, those with DPP-aberrant tumours exhibited a significantly higher likelihood of treatment failure (HR 2.01; p = 0.027).ConclusionsDNA ploidy and PTEN could serve as additional biomarkers to identify AS patients at increased risk of developing aggressive disease, enabling earlier intervention for nearly 50% of the patients that will eventually receive treatment with current protocol.

MiR-224-5p overexpression inhibits oxidative stress by regulating the PI3K/Akt/FoxO1 axis to attenuate hypoxia/reoxygenation-induced cardiomyocyte injury

To investigate the regulatory role of miRNA-224-5p in hypoxia/reoxygenation (H/R) -induced H9c2 cardiomyocyte injury. Plasma samples were collected from 160 patients with acute myocardial infarction and 80 healthy controls(HC) to measure miRNA-224-5p levels and other biochemical parameters. In cultured H9c2 cells with H/R injury, the effects of transfection with miR-224-5p mimics or a negative control sequence on cell viability, malondialdehyde (MDA) content, and superoxide dismutase 2 (SOD2) and lactate dehydrogenase (LDH) activities were tested. Dual luciferase reporter gene assay was performed to verify the targeting relationship between miR-224-5p and PTEN. Bioinformatics methods were used to analyze the potential mechanisms of the target genes. The expression of miRNA-224-5p in the treated cells was detected with qRT-PCR, the protein expressions of PTEN, Bcl-2, Bax, cleaved caspase-3, SOD2, p-PI3K/PI3K, p-Akt/Ak and p-FoxO1/FoxO1 were determined using Western blotting, and cell apoptosis was analysed with flow cytometry. The levels of blood glucose, C-reactive protein, CK, CK-MB and cTnI were significantly higher in the AMI group compared with the HC group (P < 0.05). The expression level of miR-224-5p was significantly lowered in patients with STEMI and NSTEMI and in H9c2 cells with H/R injury. The viability of H9c2 cells decreased time-dependently following H/R injury. PTEN was a target gene of miR-224-5p, and the PI3K/Akt pathway was the most significantly enriched pathway. H9c2 cells with H/R injury showed significantly decreased SOD2 activity, increased LDH activity and MDA content, increased cell apoptosis, decreased protein expression levels of p-PI3K, p-Akt, p-FoxO1, SOD2, and Bcl-2, and increased expressions of PTEN, Bax, and cleaved caspase-3. These changes were obviously attenuated by trasnfection of the cells with miR-224-5p mimics prior to H/R exposure. MiR-224-5p overexpression upregulates the expression of the antioxidant gene SOD2 through the PI3K/Akt/FoxO1 axis to relieve H/R-induced oxidative stress and reduce apoptosis of H9c2 cells.

Solasonine promotes apoptosis of non-small cell lung cancer cells by regulating the Bcl-2/Bax/caspase-3 pathway

To investigate the effect of solasonine, an active component of Solanum nigrum, on proliferation and apoptosis of non-small cell lung cancer PC9 cells. PC9 cells were treated with 2, 5, 10, 15, 20, or 25 μmol/L solasonine, and the changes in cell proliferation were examined using CCK-8 assay. Tetramethyl rhodamine ethyl ester (TMRE) was used to detect the changes in mitochondrial membrane potential, and caspase-3/7 detection kit and GreenNucTM caspase-3/Annexin V-mCherry kit for live cell were used to analyze the changes in caspase-3 of the cells. Annexin V-FITC/PI double staining was employed to analyze the apoptosis rate of the cells. The effect of PTEN inhibitors on solasonine-induced cell apoptosis was examined by detecting apoptosis-related protein expressions using Western blotting. Solasonine treatment for 24, 48, and 72 h significantly lowered the viability of PC9 cells. The cells treated with solasonine for 24 h showed significantly decreased mitochondrial membrane potential and increased cell apoptosis with enhanced caspase-3/7 and caspase-3 activities and expression of cleaved caspase-3. Solasonine treatment significantly decreased phosphorylation levels of PI3K and Akt, increased the protein expressions of PTEN and Bax, and lowered the expression of Bcl-2 protein in the cells. Solasonine inhibits proliferation and induces apoptosis of PC9 cells by regulating the Bcl-2/Bax/caspase-3 pathway and its upstream proteins.

Anticancer Activity of HER2-targeting CPP-PTEN-THP Chimeric Proteins.

Protein phosphatase and tensin homolog (PTEN) is a tumor suppressor protein with potential to be a new biotechnological drug for PTEN-deficient cancer treatment. This study aimed to develop PTEN-based chimeric proteins (CPP-PTEN-THP) for human epidermal growth factor receptor 2 (HER2)-positive breast cancer treatment, addressing current limitations like inadequate delivery, poor tumor penetration, and low selectivity, while assessing their potential HER2-specific anticancer effects. pCEFL-EGFP vector was used for both TAT-PTEN-LTV and KLA-PTEN-LTV construction. Non-contact co-cultures were employed using HEK-293T cells for protein expression, and HCC-1954 and MCF-7 cell lines for cytotoxicity testing. Protein detection was analyzed by western blotting and a docking prediction analysis was performed to infer the interactions. Endogenous and recombinant PTEN protein expression was confirmed in cell lysates. A 54-kDa signal matching the theoretical size of PTEN was detected, showing a greater level in TAT-PTEN-LTV (215.1±26.45%) and KLA-PTEN-LTV (129.2±1.44%) compared to endogenous PTEN. After the noncontact co-culture method, cytotoxic studies showed HCC-1954 preferential cell inhibition growth, with 25.95±0.9% and 12.25±1.29% inhibition by KLA-PTEN-LTV and TAT-PTEN-LTV respectively, compared to MCF-7 cells. An LTV-HER2 interaction model was proposed, inferring that LTV interactions are mainly due to the Pro, Trp, and Tyr residues that target HER2. The developed PTEN-based chimeric proteins have HER2-specific anticancer activity against HCC-1954 cells.

MiR-30a-5p attenuates hypoxia/reoxygenation-induced cardiomyocyte apoptosis by regulating PTEN protein expression and activating PI3K/Akt signaling pathway

BackgroundThis study was designed to investigate the mechanism by which miR-30a-5p mediates cardiomyocyte apoptosis after acute myocardial infarction (AMI) induced by hypoxia/reoxygenation (H/R).MethodsDifferentially expressed miRNAs were analyzed by RNA high-throughput sequencing in acute myocardial infarction (ST-elevation myocardial infarction) patients versus healthy individuals (controls). The H/R model was used to assess the regulatory mechanism of miRNAs in AMI. Lentivirus-associated vectors were used to overexpress or knock down miR-30a-5p in cellular models. The pathological mechanisms of miR-30a-5p regulating the development of acute myocardial infarction were serially explored by qPCR, bioinformatics, target gene prediction, dual luciferase, enzyme-linked immunosorbent assays (ELISAs) and Western blotting.ResultsThe results showed that the expression of miR-30a-5p was significantly increased in AMI patients and H9C2 cells. Hypoxia decreased cardiomyocyte survival over time, and reoxygenation further reduced cell survival. Bax and Phosphatase and tensin homolog (PTEN)were suppressed, while Bcl-2 was upregulated. Additionally, miR-30a-5p specifically targeted the PTEN gene. According to the GO and KEGG analyses, miR-30a-5p may participate in apoptosis by interacting with PTEN. The miR-30a-5p mimic decreased the expression of apoptosis-related proteins and the levels of the proinflammatory markers IL-1β, IL-6, and TNF-α by activating the PTEN/PI3K/Akt signaling pathway. Conversely, anti-miR-30a-5p treatment attenuated these effects. Additionally, silencing PTEN and anti-miR-30a-5p had opposite effects on H/R-induced cell apoptosis.ConclusionsmiR-30a-5p plays a crucial role in cardiomyocyte apoptosis after hypoxia-induced acute myocardial infarction. Our findings provide translational evidence that miR-30a-5p is a novel potential therapeutic target for AMI.

Downregulation of Serum PTEN Expression in Mercury-Exposed Population and PI3K/AKT Pathway-Induced Inflammation

ObjectiveThis study investigated the impact of occupational mercury (Hg) exposure on human gene transcription and expression, and its potential biological mechanisms. MethodsDifferentially expressed genes related to Hg exposure were identified and validated using gene expression microarray analysis and extended validation. Hg-exposed cell models and PTEN low-expression models were established in vitro using 293T cells. PTEN gene expression was assessed using qRT-PCR, and Western blotting was used to measure PTEN, AKT, and PI3K protein levels. IL-6 expression was determined by ELISA. ResultsCombined findings from gene expression microarray analysis, bioinformatics, and population expansion validation indicated significant downregulation of the PTEN gene in the high-concentration Hg exposure group. In the Hg-exposed cell model (25 and 10 μmol/L), a significant decrease in PTEN expression was observed, accompanied by a significant increase in PI3K, AKT, and IL-6 expression. Similarly, a low-expression cell model demonstrated that PTEN gene knockdown led to a significant decrease in PTEN protein expression and a substantial increase in PI3K, AKT, and IL-6 levels. ConclusionThis is the first study to report that Hg exposure downregulates the PTEN gene, activates the PI3K/AKT regulatory pathway, and increases the expression of inflammatory factors, ultimately resulting in kidney inflammation.

Abstract 1552: Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation

Abstract hosphatase and tensin homolog deleted on chromosome ten (PTEN) serves as a powerful tumor suppressor, and has been found to be downregulated in human bladder cancer (BC) tissues. Despite this observation, the mechanisms contributing to PTEN’s downregulation have remained elusive. In this study, we discovered that mice exposed to N-butyl-N-(4-hydroxybu-tyl)nitrosamine (BBN), a specific bladder chemical carcinogen, exhibited primary basal muscle invasive BC (BMIBC) accompanied by a pronounced reduction in PTEN protein expression in vivo. Utilizing a lncRNA deep sequencing high-throughput platform, along with gain- and loss-of-function analyses, we identified small nucleolar RNA host gene 1 (SNHG1) as a critical lncRNA that might drive the formation of primary BMIBCs in BBN-treated mice. Cell culture results further demonstrated that BBN exposure significantly induced SNHG1 in normal human bladder urothelial cell UROtsa. Notably, the ectopic expression of SNHG1 alone was sufficient to induce malignant transformation in human urothelial cells, while SNHG1 knockdown effectively inhibited anchorage-independent growth of human BMIBCs. Our detailed investigation revealed that SNHG1 overexpression led to PTEN protein degradation through its direct interaction with HUR. This interaction reduced HUR binding to ubiquitin-specific peptidase 8 (USP8) mRNA, causing degradation of USP8 mRNA and a subsequent decrease in USP8 protein expression. The downregulation of USP8, in turn, increased PTEN poly-ubiquitination and degradation, culminating in cell malignant transformation and BMIBC anchorage-independent growth. In vivo studies confirmed the downregulation of PTEN and USP8, as well as their positive correlations in both BBN-treated mouse bladder urothelium and tumor tissues of bladder cancer in nude mice.Our findings, for the first time, demonstrate that overexpressed SNHG1 competes with USP8 for binding to HUR. This competition attenuates USP8 mRNA stability and protein expression, leading to PTEN protein degradation, consequently, this process drives urothelial cell malignant transformation and fosters BMIBC growth and primary BMIBC formation. Citation Format: Chuanshu Huang, Tengda Li, Honglei Jin. Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1552.

Vitexin enhances radiosensitivity of mouse subcutaneous xenograft glioma by affecting the miR-17-5p/miR-130b-3p/PTEN/HIF-1α pathway.

Vitexin can cooperate with hyperbaric oxygen to sensitize the radiotherapy of glioma by inhibiting the hypoxia-inducible factor (HIF)-1α. However, whether vitexin has adirect radiosensitization and how it affects the HIF-1α expression remain unclear. This study investigated these issues. The SU3 cells-inoculated nude mice were divided into control, radiation, and vitexin + radiation groups. The vitexin + radiation-treated mice were intraperitoneally injected with 75 mg/kg vitexin daily for 21days. On the 3rd, 10th, and 17thdays during the vitexin treatment, the radiation-treated mice were locally irradiated with 10 Gy, respectively. In vitro, the microRNA (miR)-17-5p or miR-130b-3p mimics-transfected SU3 cells were used to examine the effects of vitexin plus radiation on expression of miR-17-5p- or miR-130b-3p-induced radioresistance-related pathway proteins. The effects of vitexin on miR-17-5p and miR-130b-3p expression in SU3 cells were also evaluated. Compared with the radiation group, the tumor volume, tumor weight, and expression of HIF-1α, vascular endothelial growth factor, and glucose transporter-1/3 proteins, miR-17-5p, and miR-130b-3p in tumor tissues in the vitexin + radiation group decreased, whereas the expression of phosphatase and tensin homolog (PTEN) protein increased. After treatment of miR-17-5p or miR-130b-3p mimics-transfected SU3 cells with vitexin plus radiation, the PTEN protein expression also increased, the HIF-1α protein expression decreased correspondingly. Moreover, vitexin decreased the miR-17-5p and miR-130b-3p expression in SU3 cells. Vitexin can enhance the radiosensitivity of glioma, and its mechanism may partly be related to the attenuation of HIF-1α pathway after lowering the inhibitory effect of miR-17-5p and miR-130b-3p on PTEN.