Stress-induced Phosphoprotein Research Articles

Stress-induced phosphoprotein 1 expression in the endometrium and myometrium of patients with adenomyosis

BACKGROUND: The study of stress-induced phosphoprotein 1 in the pathogenesis of adenomyosis is not only of theoretical interest, but this protein may be also considered as a potential biomarker of the disease. AIM: The aim of this study was to evaluate stress-induced phosphoprotein 1 expression in the endometrium and heterotopic foci in women with isolated adenomyosis and in combination with benign hyperproliferative diseases of the reproductive organs. MATERIALS AND METHODS: This study enrolled 66 women aged 21 to 47 years (34.9 ± 6.7 years), including 49 patients with adenomyosis and 17 women in the control group. The main group was divided into subgroups depending on the concomitant hyperproliferative disease such as isolated adenomyosis (n = 36), adenomyosis combined with uterine fibroids (n = 8), and adenomyosis combined with endometriosis (n = 5). The patients underwent endometrial biopsy and multifocal myometrial biopsy. Histological and immunohistochemical studies were performed to assess stress-induced phosphoprotein 1 expression in the glandular and stromal components of the endometrium and ectopic endometrial tissue within the uterine myometrium. RESULTS: We found increased stress-induced phosphoprotein 1 expression in the adenomyosis lesion compared to that in the myometrium of the control group, regardless of the phase of the menstrual cycle (p 0.001). When studying stress-induced phosphoprotein 1 expression in the endometrium of the main group in the proliferative phase of the menstrual cycle, an increase was found, but the differences were not significant. Stress-induced phosphoprotein 1 expression in the secretory phase of the menstrual cycle was higher in the glandular component of the endometrium of patients with adenomyosis compared to the levels in women in the control group (p 0.05). CONCLUSIONS: The increased expression of stress-induced phosphoprotein 1 in the glandular component of the adenomyosis lesion indicates a potential role of the protein in the pathogenesis of the disease. However, further research is needed to determine its practical significance.

Stress-induced phosphoprotein 1 (STIP1) gene expression in adenomyosis: An observational case-control study

Background. Endometriosis is distinguished by its high prevalence and significant impact on the quality of life and reproductive health of women; however, its etiology and essential pathogenesis of remain uncertain so far. Modern research is increasingly focusing on immune, hormonal and genetic factors that share a common structure and participate in common metabolism — so-called single nucleotide polymorphisms (SNPs), including stress-induced phosphoprotein 1 (STIP1), which participates in tissue and cellular metabolism through transcription splicing and folding of RNA. The role of this protein, known as heat shock protein (HSP)-organizing protein, is being actively studied in cancer and hyperproliferative diseases. The role of the STIP1 gene and its product in the pathogenesis of adenomyosis appears to be studied insufficiently, thereby determining the relevance of the present study.Objectives. To evaluate the expression of stress-induced phosphoprotein 1 in eutopic endometrium and myometrium in women with isolated adenomyosis, as well as in combination with other benign hyperproliferative diseases of the reproductive system.Methods. Clinical study site: Clinical and Diagnostic Department of Ott Research Institute of Obstetrics, Gynecology and Reproductology. Design: an observational case-control study of patients with verified diagnoses of diffuse adenomyosis, uterine fibroids, and external genital endometriosis (main group — n = 55). The study group (n = 43) was divided into three subgroups: patients with isolated diffuse adenomyosis (AM, n = 16), adenomyosis in combination with uterine fibroids (AM + UF, n = 16), adenomyosis in combination with external genital endometriosis (AM + EGE, n = 11)), a comparison group — patients with uterine fibroids (n = 12) and a control group (n = 17) — women of reproductive age without gynecological diseases. The study was conducted from November 1, 2022 to September 30, 2023. The target indicator of the study was the level of relative mRNA (mRNA) expression of STIP1 gene (in RQ (Relative Quantity) units) in the uterus — adenomyosis glands, surrounding myometrium and endometrium. Histological evaluation of the endometrium served as an additional indicator. Statistical analysis of the results obtained, namely the relative level of mRNA expression, was carried out by the ΔΔСt method using the Expression Suit V1.0.3 program. (https://www.thermofisher.com/ru/ru/home/technical-resources/software-downloads/expressionsuite-software.html). The data analysis was performed using the GraphPad Prizm program (Insight Partners, USA). Differences between groups were evaluated by means of single factor ANOVA analysis (followed by post-hoc pairwise comparisons (Tukey test) of the values in each group. The differences were considered statistically significant at p < 0.05.Results. A high level of STIP1 gene expression was reported in myometrium of patients with isolated adenomyosis (more than 3-fold increase in relation to the comparison group — patients with uterine fibroids). In addition, myometrium of women with adenomyosis combined with uterine fibroids demonstrated a higher expression of STIP1 gene, compared to patients with isolated uterine fibroids (p < 0.01). The evaluation of the expression of mRNA of the STIP1 gene in the eutopic endometrium of patients with adenomyosis and women in the control group revealed no significant differences; however, STIP1 in the endometrium of women with adenomyosis was significantly lower than in the endometrium of both patients with uterine fibroids and women with adenomyosis combined with external genital endometriosis.Conclusion. Increased mRNA expression of STIP1 gene in myometrium in adenomyosis confirms its role in the pathogenesis of this disease. The role of the expression of the STIP1 gene and the corresponding protein is to be further clarified in order to assess its specificity and sensitivity as a diagnostic marker and to identify new approaches to the treatment of adenomyosis.

Diagnostic value of serum STIP1 in HCC and AFP-negative HCC.

This study aimed to investigate the diagnostic value of stress-induced phosphoprotein 1 (STIP1) in serum for hepatocellular carcinoma (HCC) and alpha-fetoprotein (AFP)-negative HCC (ANHC). In this study, serum samples were collected from 158 HCC patients and 63 non-HCC patients. Logistic regression analysis was performed to identify independent risk factors associated with HCC and ANHC. The diagnostic values of each index for HCC and ANHC were analyzed using receiver operating characteristic (ROC) curve analysis. The STIP1, des-γ-carboxy prothrombin (DCP), and AFP levels were higher in the HCC groups than in the non-HCC groups (P < .05). Age, DCP, STIP1, and hepatitis B virus infection were independent predictors of HCC (P < .05). The diagnostic value of STIP1 for HCC was higher than that of DCP. Additionally, age, STIP1, and hepatitis B virus infection were independent predictors for ANHC patients. The ROC curve exhibited an area under the curve value of 0.919 for STIP1, with a diagnostic cutoff value of 68.5 U/mL. Moreover, 36 ANHC patients and 19 AFP-negative non-HCC patients were included to validate the diagnostic model. A total of 20 patients had STIP1 levels greater than 68.5 U/mL, resulting in diagnostic accuracy of 67.3%, sensitivity of 55.6%, and specificity of 89.5%. STIP1 demonstrates excellent diagnostic value for HCC and ANHC.

Stress-induced phosphoprotein 1: how does this co-chaperone influence the metastasis steps?

In several cancer types, metastasis is associated with poor prognosis, survival, and quality of life, representing a life risk more significant than the primary tumor itself. Metastasis is a multi-step process that spreads tumor cells from primary sites to surrounding or distant organs, originating secondary tumors. The interconnected steps that drive metastasis depend of several capabilities that enable cells to detach from the primary tumor, acquire motility and migrate through the basal membrane; invade and spread through the vascular system, and finally settle and originate a new tumor. Recently, stress-induced phosphoprotein 1 (STIP1) has emerged as a protein capable of driving tumor cells through these metastasis steps by mediating several biological processes and signaling pathways. This protein is mainly known for its function as a co-chaperone, acting as a scaffold for the interaction of its client heat-shock proteins Hsp70/90 chaperones; however, it is also known that STIP1 can act independently of chaperones to activate downstream phosphorylation pathways. The over-expression of STIP1 has been reported across various cancer types, identifying it as a potential biomarker for predicting patient prognosis and monitoring the progression of metastasis. Here, we present a discussion on how this co-chaperone mediates the initial steps of metastasis (cell adhesion loss, epithelial-to-mesenchymal transition, and angiogenesis), highlighting the biological mechanisms in which STIP1 plays a vital role, also presenting an overview of the current knowledge regarding its clinical relevance.

Polymorphism in Genes Encoding Adaptor Proteins ST13 and STIP1 and the Risk of Ischemic Stroke: a Pilot Study.

Adaptor proteins stress induced phosphoprotein 1 (STIP1) and ST13 Hsp70 interacting protein (ST13) may play a crucial role in the pathophysiology of ischemic stroke through controlling protein folding, neuronal survival, and regulation of HSP70/HSP90. The present pilot study investigated whether tagSNPs in genes encoding ST13 (rs138335, rs138344, rs7290793, and rs138344) and STIP1 (rs4980524) are associated with ischemic stroke. DNA samples from 721 ischemic stroke patients and 471 healthy controls were genotyped using the MassArray-4. Our research revealed a relationship between rs138344 ST13 and the risk of ischemic stroke, which was seen only in females (risk allele G; OR=1.34, 95%CI=1.07-1.69; p=0.01). The haplotype rs138335G-rs138344C-rs7290793C ST13 was linked with lower risk of ischemic stroke in females: OR=0.42; 95%CI=0.26-0.68; p=0.0005. Thus, ST13 represents a novel genetic marker for ischemic stroke.

The potential roles of stress-induced phosphoprotein 1 and connexin 43 in rats with reperfusion arrhythmia.

Connexin 43 (Cx43) is a critical gene for maintaining myocardial homeostasis. Interestingly, Cx43 and stress-induced phosphoprotein 1 (STIP1) were recorded to be lowly expressed in ischemia/reperfusion (I/R). However, their impacts on reperfusion arrhythmia (RA) remain to be explored. Our study aimed to find out the related underlying mechanisms. After the establishment of an isolated heart model through Langendorff perfusion, the heart rate, conduction activation time, conduction velocity, and conduction direction of the left ventricle were evaluated, along with the apoptotic rate detection in the collected myocardial tissues. After the construction of a hypoxia/reoxygenation (H/R)-induced cellular model, cell apoptosis, intercellular communication, cell viability, and the content of reactive oxygen species, superoxide dismutase, malondialdehyde, and lactic dehydrogenase were measured. The expression of Cx43 and STIP1 was determined in both rat heart and cell models. The bindings of STIP3 and Cx43 to heat shock protein 90 (HSP90) and heat shock protein 70 (HSP70) were verified. Relative to the corresponding controls, Cx43 and STIP1 were decreased in myocardial tissues of RA rats and H/R-stimulated H9C2 cells, where Cx43-binding HSP70 and HSP90 were respectively increased and decreased, and ubiquitination level of Cx43 was enhanced. STIP1 overexpression promoted protein expression of Cx43, intercellular communication, and cell viability, and reduced cell apoptosis and oxidative stress in H/R-stimulated H9C2 cells. STIP1 promoted Cx43 expression to improve intercellular communication and reduce oxidative stress in H/R-stimulated H9C2 cells.

Molecular chaperones HSP40, HSP70, STIP1, and HSP90 are involved in stabilization of Cx43.

To investigate the involvement of stress induced phosphoprotein 1 (STIP1), heat shock protein (HSP) 70, and HSP90 in ubiquitination of connexin 43 (Cx43) in rat H9c2 cardiomyocytes.Co-immunoprecipitation was used to detect protein-protein interactions and Cx43 ubiquitination. Immunofluorescence was used for protein co-localization. The protein binding, Cx43 protein expression, and Cx43 ubiquitination were reanalyzed in H9c2 cells with modified STIP1 and/or HSP90 expression.STIP1 bound to HSP70 and HSP90, and Cx43 bound to HSP40, HSP70, and HSP90 in normal H9c2 cardiomyocytes. Overexpression of STIP1 promoted the transition of Cx43-HSP70 to Cx43-HSP90 and inhibited Cx43 ubiquitination; knockdown of STIP1 resulted in the opposite effects. Inhibition of HSP90 counteracted the inhibitory effect of STIP1 overexpression on Cx43 ubiquitination.STIP1 suppresses Cx43 ubiquitination in H9c2 cardiomyocytes by promoting the transition of Cx43-HSP70 to Cx43-HSP90.

Stress induced phosphoprotein 1 overexpression controls proliferation, migration and invasion and is associated with poor survival in oral squamous cell carcinoma.

Although there have been remarkable achievements in the molecular landscape of oral squamous cell carcinoma (OSCC) in recent years, bringing advances in the understanding of its pathogenesis, development and progression, little has been applied in the prognosis and choosing the optimal treatment. In this study, we explored the influence of the stress induced phosphoprotein 1 (STIP1), which is frequently reported to be highly expressed in many cancers, in OSCCs. STIP1 expression was assessed in the TCGA database and in two independent cohorts by immunohistochemistry. Knockdown strategy was applied in OSCC cell lines to determine the impact of STIP1 on viability, proliferation, migration and invasion. The zebrafish model was applied for studying tumor formation and metastasis in vivo. The association of STIP1 and miR-218-5p was explored by bioinformatics and mimics transfection. STIP1 was highly expressed in OSCCs and significantly associated with shortened survival and higher risk of recurrence. STIP1 down-regulation decreased proliferation, migration and invasion of tumor cells, and reduced the number of metastases in the Zebrafish model. STIP1 and miR-218-5p were inversely expressed, and the transfection of miR-218-5p mimics into OSCC cells decreased STIP1 levels as well as proliferation, migration and invasion. Our findings show that STIP1 overexpression, which is inversely associated with miR-218-5p levels, contributes to OSCC aggressiveness by controlling proliferation, migration and invasion and is a determinant of poor prognosis.

Label-free quantitative proteomics and stress responses in pigs-The case of short or long road transportation.

Ethical livestock production is currently a major concern for consumers. In parallel, research has shown that transport duration is an important factor affecting animal welfare and has a negative impact on the final product quality and on the production cost. This study applied proteomics methods to the animal stress/welfare problem in pigs muscle-exudate with the aim to identify proteins indicative of molecular processes underpinning transport stress and to better characterise this species as a biomedical model. A broader perspective of the problem was obtained by applying label-free LC-MS to characterise the proteome response to transport stress (short or long road transportation) in pigs within the same genetic line. A total of 1,464 proteins were identified, following statistical analysis 66 proteins clearly separating pigs subject to short road transportation and pigs subject long road transportation. These proteins were mainly involved in cellular and metabolic processes. Catalase and stress-induced phosphoprotein-1 were further confirmed by Western blot as being involved in the process of self-protection of the cells in response to stress. This study provide an insight into the molecular processes that are involved in pig adaptability to transport stress and are a step-forward for the development of an objective evaluation method of stress in order to improve animal care and management in farm animals.

JAK2-Mediated Phosphorylation of Stress-Induced Phosphoprotein-1 (STIP1) in Human Cells

Stress-induced phosphoprotein-1 (STIP1)—a heat shock protein (HSP)70/HSP90 adaptor protein—is commonly overexpressed in malignant cells, where it controls proliferation via multiple signaling pathways, including JAK2/STAT3. We have previously shown that STIP1 stabilizes the protein tyrosine kinase JAK2 in cancer cells via HSP90 binding. In this study, we demonstrate that STIP1 may act as a substrate for JAK2 and that phosphorylation of tyrosine residues 134 and 152 promoted STIP1 protein stability, induced its nuclear-cytoplasmic shuttling, and promoted its secretion into the extracellular space. We also found that JAK2-mediated STIP1 phosphorylation enhanced cell viability and increased resistance to cisplatin-induced cell death. Conversely, interference STIP1 with JAK2 interaction—attained either through site-directed mutagenesis or the use of cell-penetrating peptides—decreased JAK2 protein levels, ultimately leading to cell death. On analyzing human ovarian cancer specimens, JAK2 and STIP1 expression levels were found to be positively correlated with each other. Collectively, these results indicate that JAK2-mediated phosphorylation of STIP-1 is critical for sustaining the JAK2/STAT3 signaling pathway in cancer cells.

Hypoglycemia Impairs the Heat Shock Protein Response: A Risk for Heat Shock in Cattle?

BackgroundHeat stress (HS) in cattle is a major debilitating problem, affecting health and milk yield. Physiologically, HS has been shown to lower blood glucose levels to 2.5 mmol/l (45 mg/dl) and results in upregulation of heat shock proteins (HSPs), eliciting the heat shock response (HSR) of which HSP90, 70 and 27 have been shown to be protective. However, it is unclear if the HSP response is blunted by decreased glucose, thereby preventing adaptive mechanisms. To address this question, this exploratory reverse translational study on the effects of hypoglycemia on the HSP pathway was undertaken.MethodsA human prospective, study in healthy control individuals (n = 23) was undertaken. Subjects underwent hyperinsulinemic-induced hypoglycemia [≤2.0 mmol/L (36 mg/dl)] with blood sampling at baseline, at hypoglycemia and for a 24-h post-hypoglycemia follow-up period. Proteomic analysis of the heat shock-related protein pathway, the pathway associated with HS in cattle, was performed.ResultsIn response to hypoglycemia, HS pathway proteins were significantly decreased (p < 0.05): HSP70 and HSP27 (at hypoglycemia); DnaJ homolog subfamily B member 1 (DNAJB1), Stress-induced-phosphoprotein 1 (STIP1) and the ubiquitin pathway proteins, Ubiquitin-conjugating enzyme (UBE2L3) and Ubiquitin-conjugating enzyme E2 N (UBE2N) (at 30-min post-hypoglycemia); HSP90 (at 2-h post-hypoglycemia). STIP1, UBE2L3, and UBE2N remained suppressed at 24-h.ConclusionHeat stress in cattle reduces blood glucose that, in turn, may blunt the HS pathway protective response, including HSP 90, 70, 27 and the ubiquitin proteins, leading to adverse outcomes. Monitoring of blood glucose in susceptible cattle may allow for earlier intervention and may also identify those animals at greatest risk to ensure that milk yield is not compromised.

Stress-induced phosphoprotein 1 restrains spinal cord ischaemia-reperfusion injury by modulating NF-κB signalling.

Spinal cord injury (SCI), a major cause of disability, causes high global disease and economic burdens. Stress‐induced phosphoprotein 1 (STIP1) has been identified to be involved in spinal cord ischaemia‐reperfusion injury (SCII); however, the effect of STIP1 on SCII remains unclear until now. This study aimed to examine the role of STIP1 in SCII and unravel the possible mechanisms. Western blotting and immunohistochemical staining showed that STIP1 expression rapidly increased and then decreased in rat spinal cord following SCII treatment. Neurological function scoring, HE staining, immunohistochemical staining and Western blotting revealed that STIP1 overexpression alleviated SCII‐induced motor dysfunction of hind limbs, neuronal loss and inflammation in spinal cord, and inhibited activity of nuclear factor kappa B (NF‐κB) signalling in rats. Immunoprecipitation identified that STIP1 was co‐located with Iba‐1. In addition, STIP1 was found to ameliorate oxygen and glucose deprivation (OGD)‐induced inflammation and activation of NF‐κB signalling in mouse microglia BV2 cells, and STIP1 resulted in decrease of heat shock protein family A member 8 (HSPA8), increase of IκBβ expression and reduced binding of IκBβ to HSPA8 in BV2 cells. The results of the present study demonstrate that STIP1 alleviates ischaemia/reperfusion‐induced neuronal injury and inflammation in rat spinal cord and mouse microglial cells by deactivating NF‐κB signalling. These findings may provide novel insights for the clinical diagnosis and treatment of SCI.

Antioxidant Resveratrol Increases Lipolytic and Reduces Lipogenic Gene Expression under In Vitro Heat Stress Conditions in Dedifferentiated Adipocyte-Derived Progeny Cells from Dairy Cows.

Heat stress (HS) induces oxidative stress by increasing reactive oxygen species (ROS), and the polyphenol resveratrol (RSV) has been shown to have antioxidant properties by reducing ROS. Hence, we aimed to examine the effects of RSV, HS and their interaction on bovine adipocytes. We generated bovine dedifferentiated adipocyte-derived progeny (DFAT) cells from subcutaneous adipose tissue and examined the effects of RSV (100 µM), heat conditions: isothermal (ISO-37 °C), short heat (SH-41.2 °C for 1 h) and long HS (LH-41.2 °C for 16 h), and their interaction on gene expression in DFAT-cells. In medium of DFAT-cells treated with RSV, malondialdehyde levels were reduced and oxygen-radical absorbance-capacity levels were increased compared to control. Treating DFAT-cells with RSV increased the relative mRNA expression of stress-induced-phosphoprotein-1 (STIP1) and the expression of hormone-sensitive-lipase (LIPE) and perilipin-1 (PLIN1), whereas it reduced the expressions of fatty-acid-synthase (FASN) and of pro-inflammatory chemotactic-C-C-motif-chemokine-ligand-2 (CCL2) also under HS. Moreover, reduced protein abundance of FASN was found in RSV-treated DFAT-cells compared to controls. Molecular docking of RSV with FASN confirmed its possible binding to FASN active site. This work demonstrates that RSV has an antioxidant effect on bovine DFAT cells and may induce adipose lipolysis and reduce lipogenesis also under in vitro HS conditions.

Proteomic Analysis Reveals That Metformin Suppresses PSMD2, STIP1, and CAP1 for Preventing Gastric Cancer AGS Cell Proliferation and Migration.

Metformin is one of the most widely used anti-diabetic drugs in type-II diabetes treatment. The mechanism of decreasing blood glucose is believed to suppress hepatic gluconeogenesis by increasing muscular glucose uptake and insulin sensitivity. Recent studies suggest that metformin may reduce cancer risk; however, its anticancer mechanism in gastric cancers remains unclear. Here, we aim to evaluate the anticancer effects of metformin on human gastric adenocarcinoma (AGS) cells. Our results showed that metformin inhibited AGS cell proliferation in a dose-dependent manner. Using small-scale quantitative proteomics, we identified 177 differentially expressed proteins upon metformin treatment; among these, nine proteins such as 26S proteasome non-ATPase regulatory subunit 2 (PSMD2), stress-induced phosphoprotein 1 (STIP1), and adenylyl cyclase-associated protein 1 (CAP1) were significantly altered. We found that metformin induced cell cycle arrest at the G0/G1 phase, suppressed cell migration, and affected cytoskeleton distribution. Additionally, patients with highly expressed PSMD2, STIP1, and CAP1 have a poor clinical outcome. Our study provides a novel view of developing therapies for gastric cancer.

STIP1 knockdown suppresses colorectal cancer cell proliferation, migration and invasion by inhibiting STAT3 pathway

Stress-induced phosphoprotein 1 (STIP1) plays an important role in cancer tumorigenesis and progression. However, the role of STIP1 in colorectal cancer (CRC) remains unclear. This study aimed to explore clinical significance, biological function and potential molecular mechanism of STIP1 in CRC. Immunohistochemistry (IHC) and Western bolt were performed to detect STIP1 protein level in CRC and adjacent normal tissues. DLD1 and HCT116 cell lines were treated with shSTIP1, cell proliferation was detected by CCK8 and colony formation assays, and cell migration and invasion were detected by wound healing and transwell assays. Moreover, western blot and immunofluorescence assays were performed to explore the potential molecular mechanism of STIP1 in the progression of CRC. We found that STIP1 expression in CRC tissues was significantly higher than in adjacent normal tissues. High STIP1 expression was associated with poor overall survival (OS) in CRC patients. Furthermore, secreted STIP1 promoted CRC cell proliferation and invasion through STAT3 signaling pathway, while STIP1 knockdown inhibited the proliferation, migration and invasion of CRC cells. Mechanistically, STIP1 knockdown suppressed the activation of STAT3 signaling pathway in CRC. In conclusion, STIP1 knockdown suppresses CRC cell proliferation, migration and invasion by inhibiting the activation of STAT3 signaling, and STIP1 is a potential target for CRC therapy.

Stress-induced phosphoprotein 1 facilitates breast cancer cell progression and indicates poor prognosis for breast cancer patients.

Breast cancer (BC) threatened the life health of a tremendous amount of the population, and the estimated number of death is still rising nowadays. We found that stress-induced phosphoprotein 1 (STIP1) is overexpressed in BC tissues compared to non-tumorous breast tissues. Our study is to validate the prognostic value of STIP1 and investigate its biological role in BC. We verified the upregulation of STIP1 in multiple databases, proved that STIP1 is upregulated in BC tissues and cell lines using real-time quantitative PCR (qRT-PCR). We used small interfering RNA to examine the function of STIP1 in BC cell lines (BT-549, MDA-MB-231, Hs-578T) and explored the mechanism of function of STIP1 in BC cells using Western blotting and qRT-PCR. Analyses of multiple databases indicated that high STIP1 expression is a marker that effectively distinguishes BC patients from healthy control and predicts worse clinical outcomes in BC. The loss-of-function experiments showed that STIP1 silencing results in inhibition of cell proliferation and migration, inducing cell apoptosis, and S-phase arrest in vitro. Our study also showed that STIP1 downregulation inhibited the JAK2/STAT3 pathway and epithelial-mesenchymal transition process. Rescue experiments demonstrated that the oncogenic effect of STIP1 is partially dependent on mediating JAK2 expression. This study verified that STIP1 is an oncogenic gene that promotes BC progression and serves as a valuable diagnostic and outcome-related marker of BC.

Intracellular targeting of STIP1 inhibits human cancer cell line growth.

BackgroundExtracellular and cell-surface molecules remain the most common druggable cancer targets. However, intracellular therapeutic modalities are gaining momentum. The overexpression of stress-induced phosphoprotein 1 (STIP1), an adaptor protein that coordinates the functions of different chaperones in protein folding, has been reported in several solid malignancies. Here, we investigated the effects of intracellular STIP1 inhibition, attained either through the HEPES-mediated cytosolic delivery of anti-STIP1 antibodies or the use of a cell-penetrating signal-tagged peptide 520, in different human cancer cell lines and luciferase-expressing murine ovarian cancer cells (MOSEC/Luc) tumor-bearing C57BL/6 mice.MethodsThe effects of STIP1 in different human cell lines were determined by cell viability, cell cytotoxicity and cell apoptosis assays. Immunoblotting was used to assess the relevant proteins found in this study and tumor xenograft mice models were also employed.ResultsIntracellular targeting of STIP1 inhibited cancer cell line growth and promoted caspase 3-dependent apoptotic cell death. Moreover, the intracellular delivery of anti-STIP1 antibodies facilitated the degradation of STIP1 and two of its client proteins, lysine-specific demethylase 1 and Janus kinase 2. In vivo studies demonstrated that survival of mice bearing experimental tumors was improved by administration of anti-STIP1 antibodies.ConclusionsOur findings demonstrate that the cytosolic inhibition of STIP1 in tumor cells is feasible and provides a solid basis for further investigation of STIP1 as an intracellular cancer target. Our findings demonstrate that cytosolic inhibition of STIP1 in tumor cells is feasible and provide a solid basis for further exploration of STIP1 as an intracellular cancer target.

Aptamer modified nanoprobe for multimodal fluorescence/magnetic resonance imaging of human ovarian cancer cells

A multifunctional-aptamer (APT) nanoprobe, TOV6 APT-superparamagnetic iron oxide nanoparticle-carbon dots (APT-SPION-CDs), for fluorescence and magnetic resonance targeted imaging (FI/MRI) of human ovarian cancer cells (OVCAR-3) is introduced. The SPION-CDs were synthesized and conjugated with TOV6 APT recognizing the stress-induced phosphoprotein 1 (STIP1) overexpressed on OVCAR-3 cells. The capability of the nanoprobe as a contrast agent for MRI and simultaneously as a fluorescent probe for fluorescence microscopy was studied. TOV6 APTs were adsorbed on SPION-CDs and were confirmed with Fourier transform infrared spectrometer. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed higher cytotoxic effects for APT-SPION-CDs compared to SPION-CDs on STIP1-negative HeLa cells. But on OVCAR-3, as STIP1-positive cells, the cytotoxic effect was negligible. The fluorescence microscopic images confirmed that APT-SPION-CDs specifically targeted ovarian cancer cells due to the tumor-targeting effect of TOV6 APT. High spin–spin relaxivity value (r2 = 308.5 mM−1 s−1) and the signal enhancement in T2-weighted MRIs confirmed the capability of the nanoprobe as a T2-based contrast agent. In vitro cellular uptake and signal enhancement of this multimodal FI/MRI nanoprobe demonstrated the potential application of APT-SPION-CDs as a contrast agent for MRI and as a fluorescent probe for fluorescence microscopic imaging.

Effects of STIP1 and GLCCI1 polymorphisms on the risk of childhood asthma and inhaled corticosteroid response in Chinese asthmatic children

BackgroundAsthma is a common chronic lung disease in children. We aimed to determine the associations between stress-induced phosphoprotein 1 (STIP1) and glucocorticoid-induced transcript 1 (GLCCI1) polymorphisms and susceptibility of childhood asthma and inhaled corticosteroid (ICS) response in children.MethodsA total of 263 Chinese Han asthmatic children were recruited from the Xiangya Hospital, Central South University. Pulmonary function tests were performed before the treatment and 3 months after the treatment. One hundred fifty non-asthmatic children were recruited. Each participant’s DNA was extracted from the peripheral blood and Method of MassARRAY was used to genotype the single-nucleotide polymorphisms (SNPs).ResultsSTIP1 rs2236647 wild-type homozygote (CC) was associated with increased asthma risk of children (OR = 1.858, 95% CI:1.205–2.864), but not associated with the ICS response. GLCCI1 rs37969, rs37972 and rs37973 polymorphisms were not associated with the risk of childhood asthma. However, rs37969 mutant genotypes (TT/GT) were significantly associated with less improvement in PD20 (p = 0.028). We also found significant associations between rs37969, rs37972 and rs37973 mutant genotypes and less improvement in maximal midexpiratory flow (MMEF) after ICS treatment for 3 months (p = 0.036, p = 0.010 and p = 0.003, respectively).ConclusionsSTIP1 rs2236647 was associated with asthma risk of children and GLCCI1 rs37969 mutant genotypes were associated with less improvement in airway hyper-responsiveness. GLCCI1 rs37969, rs37972 and rs37973 polymorphisms might be associated with pulmonary function in childhood asthma patients after ICS treatment.

Knockdown of STIP1 inhibits the invasion of CD133‑positive cancer stem‑like cells of the osteosarcoma MG63cellline via the PI3K/Akt and ERK1/2 pathways.

Osteosarcoma is the most common primary malignant tumor of the bone in adolescents and children, with high rates of metastasis and a poor prognosis. Recently, osteosarcoma cancer stem/stem‑like cells(CSCs) have been identified as the main cause of recurrence and metastasis. Stress‑induced phosphoprotein1 (STIP1), a co‑chaperone that binds to heat shock proteins70 and90, is abnormally expressed in several tumor cell lines, and may play an important role in tumor cell migration and invasion. These features indicate that STIP1 may represent a new therapeutic target for osteosarcoma CSCs. However, the role of STIP1 in osteosarcoma CSC migration and invasion remains largely unknown. In the present study, CD133‑positive osteosarcoma CSCs were first isolated and cultured by magnetic cell sorting and serum‑free medium suspension cell sphere culture, respectively. Knockdown of STIP1 by small interfering RNA significantly was then shown to inhibit the migration and invasion of these cells, possibly due to the regulation of the expression of matrix metalloproteinase (MMP)‑2, MMP‑9 and tissue inhibitor of metalloproteinase‑2. Furthermore, data from the present study suggested that the knockdown of STIP1 decreased the levels of phosphorylated Akt and phosphorylated ERK1/2. In summary, these findings indicate that targeting STIP1 in osteosarcoma may constitute a viable molecular targeted therapy strategy for the inhibition of CSC invasion and migration.