The emerging role of exosomes in survivin secretion

Survivin degradation by bergenin overcomes pemetrexed resistance

PURPOSE

Chemoresistance is a primary factor for treatment failure and tumor recurrence in non-small cell lung cancer (NSCLC) patients. The oncoprotein survivin is commonly upregulated in human malignancies and is associated with poor prognosis, but its effect on carcinogenesis and chemoresistance in NSCLC is not yet evident, and to explore an effective inhibitor targeting survivin expression is urgently needed.

METHODS

The protumor characteristics of survivin and antitumor activities of bergenin in NSCLC cells were examined by MTS, colony formation assays, immunoblot, immunohistochemistry, and in vivo xenograft development.

RESULTS

Survivin was upregulated in non-small cell lung cancer (NSCLC) tissues, while its depletion inhibited NSCLC tumorigenesis. The current study focused on bergenin, identifying its effective antitumor effect on NSCLC cells both in vivo and in vitro. The results showed that bergenin could inhibit cell proliferation and induce the intrinsic pathway of apoptosis via downregulating survivin. Mechanistically, bergenin reduced the phosphorylation of survivin via inhibiting the Akt/Wee1/CDK1 signaling pathway, thus resulting in enhanced interaction between survivin and E3 ligase Fbxl7 to promote survivin ubiquitination and degradation. Furthermore, bergenin promoted chemoresistance in NSCLC cells re-sensitized to pemetrexed treatment.

CONCLUSIONS

Survivin overexpression is required for maintaining multiple malignant phenotypes of NSCLC cells. Bergenin exerts a potent antitumor effect on NSCLC via targeting survivin, rendering it a promising agent for the treatment of NSCLC.

AKR1B10 expression in benign prostatic hyperplasia and its related mechanism

The aim of the present study was to investigate the expression of aldo-keto reductase family 1 member B10 (AKR1B10) in benign prostatic hyperplasia (BPH) and its related mechanism. In total, 142 BPH patients admitted from March 2017 to March 2019 at the First Hospital of Hunan University of Chinese Medicine and 140 healthy people undergoing physical examination were selected as the research subjects. The clinical value of AKR1B10 in BPH was analyzed. Twenty clean SD rats were selected, and 10 were selected to establish the prostate hyperplasia model, while the remaining 10 were set as the control group. Ten days after the model was established, AKR1B10 and NF-κB expression in prostate tissues of rats in both groups was detected by PCR and immunohistochemistry. The primary cells in prostate hyperplasia were cultured, and then they were transfected with AKR1B10 to observe the changes of cell biological behavior. AKR1B10 and NF-κB mRNA significantly increased in peripheral blood of BPH patients and prostate tissue of BPH model rats (P<0.001), and AKR1B10 had good diagnostic value for BPH (P<0.001). In addition, it was positively correlated with PSA, EGF, IL-6 and TNF-α (P<0.001). After transfection with AKR1B10-inhibitor, it was revealed that the proliferation of prostate hyperplasia cells decreased, while the apoptosis of prostate hyperplasia cells increased and the NF-κB protein expression decreased (P<0.001). Collectively, high expression of AKR1B10 in BPH promoted the proliferation of prostate cells and reduced their apoptosis, and the mechanism may be through regulation of NF-κB.

Exosomes as Naturally Occurring Vehicles for Delivery of Biopharmaceuticals: Insights from Drug Delivery to Clinical Perspectives

Exosomes as nanosized vesicles are emerging as drug delivery systems for therapeutics owing to their natural origin, their ability to mediate intercellular communication, and their potential to encapsulate various biological molecules such as proteins and nucleic acids within the lipid bilayer membrane or in the lumen. Exosomes contain endogenous components (proteins, lipids, RNA) that could be used to deliver cargoes to target cells, offering an opportunity to diagnose and treat various diseases. Owing to their ability to travel safely in extracellular fluid and to transport cargoes to target cells with high efficacy, exosomes offer enhanced delivery of cargoes in vivo. However, several challenges related to the stabilization of the exosomes, the production of sufficient amounts of exosomes with safety and efficacy, the efficient loading of drugs into exosomes, the clearance of exosomes from circulation, and the transition from the bench scale to clinical production may limit their development and clinical use. For the clinical use of exosomes, it is important to understand the molecular mechanisms behind the transport and function of exosome vesicles. This review exploits techniques related to the isolation and characterization of exosomes and their drug delivery potential to enhance the therapeutic outcome and stabilization methods. Further, routes of administration, clinical trials, and regulatory aspects of exosomes will be discussed in this review.

Tumor Suppressor Protein p53 and Inhibitor of Apoptosis Proteins in Colorectal Cancer-A Promising Signaling Network for Therapeutic Interventions

Simple Summary

Tumor suppressor 53 (p53) is a multifunctional protein that regulates cell cycle, DNA repair, apoptosis and metabolic pathways. In colorectal cancer (CRC), mutations of the gene occur in 60% of patients and are associated with a more aggressive tumor phenotype and resistance to anti-cancer therapy. In addition, inhibitor of apoptosis (IAP) proteins are distinguished biomarkers overexpressed in CRC that impact on a diverse set of signaling pathways associated with the regulation of apoptosis/autophagy, cell migration, cell cycle and DNA damage response. As these mechanisms are further firmly controlled by p53, a transcriptional and post-translational regulation of IAPs by p53 is expected to occur in cancer cells. Here, we aim to review the molecular regulatory mechanisms between IAPs and p53 and discuss the therapeutic potential of targeting their interrelationship by multimodal treatment options.

Abstract

Despite recent advances in the treatment of colorectal cancer (CRC), patient’s individual response and clinical follow-up vary considerably with tumor intrinsic factors to contribute to an enhanced malignancy and therapy resistance. Among these markers, upregulation of members of the inhibitor of apoptosis protein (IAP) family effects on tumorigenesis and radiation- and chemo-resistance by multiple pathways, covering a hampered induction of apoptosis/autophagy, regulation of cell cycle progression and DNA damage response. These mechanisms are tightly controlled by the tumor suppressor p53 and thus transcriptional and post-translational regulation of IAPs by p53 is expected to occur in malignant cells. By this, cellular IAP1/2, X-linked IAP, Survivin, BRUCE and LIVIN expression/activity, as well as their intracellular localization is controlled by p53 in a direct or indirect manner via modulating a multitude of mechanisms. These cover, among others, transcriptional repression and the signal transducer and activator of transcription (STAT)3 pathway. In addition, p53 mutations contribute to deregulated IAP expression and resistance to therapy. This review aims at highlighting the mechanistic and clinical importance of IAP regulation by p53 in CRC and describing potential therapeutic strategies based on this interrelationship.

Neuroimaging and advanced research techniques may lead to improved outcomes in military members suffering from traumatic brain injury

Recent military conflicts in Iraq and Afghanistan have resulted in the significant increase in blast-related traumatic brain injury (TBI), leading to increased Department of Defense interest in its potential long-term effects ranging from the mildest head injuries termed subconcussive trauma to the most debilitating termed chronic traumatic encephalopathy (CTE). Most patients with mild TBI will recover quickly while others report persistent symptoms called postconcussive syndrome. Repeated concussive and subconcussive head injuries result in neurodegenerative conditions that may hinder the injured for years. Fundamental questions about the nature of these injuries and recovery remain unanswered. Clinically, patients with CTE present with either affective changes or cognitive impairment. Genetically, there have been no clear risk factors identified. The discovery that microglia of the cerebral cortex discharged small extracellular vesicles in the injured and adjacent regions to a TBI may soon shed light on the immediate impact injury mechanisms. The combination of neuroimaging and advanced research techniques may, one day, fill critical knowledge gaps and lead to significant TBI research and treatment advancements.

The Presence of Survivin on B Cells from Myasthenia Gravis Patients and the Potential of an Antibody to a Modified Survivin Peptide to Alleviate Weakness in an Animal Model

Myasthenia gravis (MG) is an autoimmune disease in which Abs target neuromuscular junction proteins, in particular the acetylcholine receptor. We previously identified the antiapoptotic protein survivin in the autoreactive B cells and plasma cells of MG patients. To further define the role of survivin in MG, we have assessed PBMCs from 29 patients with MG and 15 controls. We confirmed the increased expression of survivin in CD20⁺ lymphocytes from MG patients compared with controls. Furthermore, the CD20⁺ population of cells from MG patients contained a higher percentage of extracellular survivin compared with controls. The analysis of CD4⁺ cells showed an increased percentage of intracellular survivin in MG patients compared with controls, whereas the extracellular survivin CD4⁺ percentage was unaffected. In an experimental mouse model of MG, we assessed the therapeutic potential of an Ab raised to a modified survivin peptide but cross-reactive to survivin. Ab treatment reduced disease severity, lowered acetylcholine receptor-specific Abs, and decreased CD19⁺ survivin⁺ splenocytes. The ability to target survivin through Ab recognition of autoreactive cells offers the potential for a highly specific therapeutic agent for MG.

Phosphorylation Modulates Survivin Function in Behcet's Disease

Purpose: Survivin is critical for proliferation, maturation, homeostasis and differentiation of effector and memory lymphocytes. In this study the baculoviral inhibitors of apoptosis proteins (IAPs) repeat containing 5 (BIRC5) mRNA, survivin, and phosphorylated survivin expression were evaluated in peripheral blood mononuclear cells (PBMCs), and plasma of patients with Behcet’s disease (BD).

Methods: In this study, 26 Iranian Azari patients diagnosed with BD and 30 healthy controls were recruited. Total RNA was extracted from PBMCs. The expression level of survivin was measured by quantitative real-time polymerase chain reaction (PCR). Survivin plasma levels were measured using survivin Enzyme-linked immunosorbent assays. Also, western blotting analysis was performed to measure phosphorylated-survivin and survivin levels in PBMCs and plasma of patients with BD.

Results: In a pilot study, we showed that BIRC5 gene expression increased in BD patients compared with healthy controls (P<0.05). Western blotting analysis indicated that there was an increase in phosphorylated survivin expression in PBMCs of BD patients. Our data from western blot analysis showed survivin level in plasma samples of BD patients was similar to healthy controls. No significant differences were observed between plasma survivin levels in the BD patients compared with control group (P>0.05). The expression of phosphorylated survivin at Thr34 in PBMCs of BD patients with active disease was increased. Plasma phosphorylated survivin levels in having BD patients were also downregulated compared to healthy individuals.

Conclusion: Analysis of PBMCs indicated increasing expression level of phosphorylated survivin in PBMCs of BD patients. There was also a downregulation in phosphorylated survivin levels in plasma of BD patients.

Survivin Overexpression Has a Negative Effect on Feline Calicivirus Infection

It is known that levels of the anti-apoptotic protein survivin are reduced during Murine norovirus MNV-1 and Feline calicivirus (FCV) infection as part of the apoptosis establishment required for virus release and propagation in the host. Recently, our group has reported that overexpression of survivin causes a reduction of FCV protein synthesis and viral progeny production, suggesting that survivin may affect early steps of the replicative cycle. Using immunofluorescence assays, we observed that overexpression of survivin, resulted in the reduction of FCV infection not only in transfected but also in the neighboring nontransfected CrFK cells, thus suggesting autocrine and paracrine protective effects. Cells treated with the supernatants collected from CrFK cells overexpressing survivin showed a reduction in FCV but not MNV-1 protein production and viral yield, suggesting that FCV binding and/or entry were specifically altered. The reduced ability of FCV to bind to the surface of the cells overexpressing survivin, or treated with the supernatants collected from these cells, correlate with the reduction in the cell surface of the FCV receptor, the feline junctional adhesion molecule (fJAM) 1, while no effect was observed in the cells transfected with the pAm-Cyan vector or in cells treated with the corresponding supernatants. Moreover, the overexpression of survivin affects neither Vaccinia virus (VACV) production in CrFK cells nor MNV-1 virus production in RAW 267.4 cells, indicating that the effect is specific for FCV. All of these results taken together indicate that cells that overexpress survivin, or cell treatment with the conditioned medium from these cells, results in the reduction of the fJAM-1 molecule and, therefore, a specific reduction in FCV entry and infection.

Biomarkers of gastric cancer: Current topics and future perspective

Gastric cancer (GC) is one of the most prevalent malignant types in the world and an aggressive disease with a poor 5-year survival. This cancer is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Although the incidence is declining, the outcome of patients with GC remains dismal. Thus, the detection at an early stage utilizing useful screening approaches, selection of an appropriate treatment plan, and effective monitoring is pivotal to reduce GC mortalities. Identification of biomarkers in a basis of clinical information and comprehensive genome analysis could improve diagnosis, prognosis, prediction of recurrence and treatment response. This review summarized the current status and approaches in GC biomarker, which could be potentially used for early diagnosis, accurate prediction of therapeutic approaches and discussed the future perspective based on the molecular classification and profiling.

The Rules and Functions of Nucleocytoplasmic Shuttling Proteins

Biological macromolecules are the basis of life activities. There is a separation of spatial dimension between DNA replication and RNA biogenesis, and protein synthesis, which is an interesting phenomenon. The former occurs in the cell nucleus, while the latter in the cytoplasm. The separation requires protein to transport across the nuclear envelope to realize a variety of biological functions. Nucleocytoplasmic transport of protein including import to the nucleus and export to the cytoplasm is a complicated process that requires involvement and interaction of many proteins. In recent years, many studies have found that proteins constantly shuttle between the cytoplasm and the nucleus. These shuttling proteins play a crucial role as transport carriers and signal transduction regulators within cells. In this review, we describe the mechanism of nucleocytoplasmic transport of shuttling proteins and summarize some important diseases related shuttling proteins.

Peritoneal carcinomatosis: limits of diagnosis and the case for liquid biopsy

Peritoneal Carcinomatosis (PC) is a late stage manifestation of several gastrointestinal malignancies including appendiceal, colorectal, and gastric cancer. In PC, tumors metastasize to and deposit on the peritoneal surface and often leave patients with only palliative treatment options. For colorectal PC, median survival is approximately five months, and palliative systemic therapy is able to extend this to approximately 12 months. However, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) with a curative intent is possible in some patients with limited tumor burden. In well-selected patients undergoing complete cytoreduction, median survival has been reported as high as 63 month. Identifying patients earlier who are either at risk for, or who have recently developed PC may provide them with additional treatment options such as CRS/HIPEC. PC is diagnosed late by imaging findings or often times during an invasive procedures such as laparoscopy or laparotomy. In order to improve the outcomes of PC patients, a minimally invasive, accurate, and specific PC screening method needs to be developed. By utilizing circulating PC biomarkers in the serum of patients, a “liquid biopsy,” may be able to be generated to allow a tailored treatment plan and early intervention. Exosomes, stable patient-derived nanovesicles present in blood, urine, and many other bodily fluids, show promise as a tool for the evaluation of labile biomarkers. If liquid biopsies can be perfected in PC, manifestations of this cancer may be more effectively treated, thus offering improved survival.

Evaluation of a New Survivin ELISA and UBC® Rapid for the Detection of Bladder Cancer in Urine

Urine-based biomarkers for non-invasive diagnosis of bladder cancer are urgently needed. No single marker with sufficient sensitivity and specificity has been described so far. Thus, a combination of markers appears to be a promising approach. The aim of this case-control study was to evaluate the performance of an in-house developed enzyme-linked immunosorbent assay (ELISA) for survivin, the UBC^®Rapid test, and the combination of both assays. A total of 290 patients were recruited. Due to prior bladder cancer, 46 patients were excluded. Urine samples were available from 111 patients with bladder cancer and 133 clinical controls without urologic diseases. Antibodies generated from recombinant survivin were utilized to develop a sandwich ELISA. The ELISA and the UBC^®Rapid test were applied to all urine samples. Receiver operating characteristic (ROC) analysis was used to evaluate marker performance. The survivin ELISA exhibited a sensitivity of 35% with a specificity of 98%. The UBC^®Rapid test showed a sensitivity of 56% and a specificity of 96%. Combination of both assays increased the sensitivity to 66% with a specificity of 95%. For high-grade tumors, the combination showed a sensitivity of 82% and a specificity of 95%. The new survivin ELISA and the UBC^®Rapid test are both able to detect bladder cancer, especially high-grade tumors. However, the performance of each individual marker is moderate and efforts to improve the survivin assay should be pursued. A combination of both assays confirmed the benefit of using marker panels. The results need further testing in a prospective study and with a high-risk population.

Racial differences in the expression of inhibitors of apoptosis (IAP) proteins in extracellular vesicles (EV) from prostate cancer patients

African-American men with prostate cancer typically develop more aggressive tumors than men from other racial/ethnic groups, resulting in a disproportionately high mortality from this malignancy. This study evaluated differences in the expression of inhibitors of apoptosis proteins (IAPs), a known family of oncoproteins, in blood-derived exosomal vesicles (EV) between African-American and European-American men with prostate cancer. The ExoQuick™ method was used to isolate EV from both plasma and sera of African-American (n = 41) and European-American (n = 31) men with prostate cancer, as well as from controls with no cancer diagnosis (n = 10). EV preparations were quantified by acetylcholinesterase activity assays, and assessed for their IAP content by Western blotting and densitometric analysis. Circulating levels of the IAP Survivin were evaluated by ELISA. We detected a significant increase in the levels of circulating Survivin in prostate cancer patients compared to controls (P<0.01), with the highest levels in African-American patients (P<0.01). African-American patients with prostate cancer also contained significantly higher amounts of EVs in their plasma (P<0.01) and sera (P<0.05) than European-American patients. In addition, EVs from African-American patients with prostate cancer contained significantly higher amounts of the IAPs Survivin (P<0.05), XIAP (P<0.001), and cIAP-2 (P<0.01) than EVs from European-American patients. There was no significant correlation between expression of IAPs and clinicopathological parameters in the two patient groups. Increased expression of IAPs in EVs from African-American patients with prostate cancer may influence tumor aggressiveness and contribute to the mortality disparity observed in this patient population. EVs could serve as reservoirs of novel biomarkers and therapeutic targets that may have clinical utility in reducing prostate cancer health disparities.

Uptake of lymphoma-derived exosomes by peripheral blood leukocytes

Exosomes are nanosized lipid vesicles secreted into blood and other body fluids and serve as vehicles for intercellular communication. Despite being an important component of the tumor microenvironment (TME), exosomal targeting and uptake into recipient cells are still not fully understood. Few studies have looked at lymphoma exosomes and their interactions with circulating blood cells. In this study, we examine the exosomal uptake distribution among peripheral blood leukocytes (PBLs) using vesicles derived from a diffuse large B cell lymphoma cell line, WSU-DLCL2. Lymphoma cells survive, proliferate, and are protected from the cytotoxic effects of chemotherapeutic agents by soluble factors or by direct contact with inflammatory and stromal cells within the TME. In an attempt to close the gap in knowledge concerning lymphoma TME immunosuppression, we have treated normal human PBLs with PKH67-labeled lymphoma exosomes and monitored the uptake by measuring fluorescence at different time points using flow cytometry and fluorescent microscopy. Our results show that of the four populations examined, B cells and monocytes demonstrated uptake of PKH67-labeled exosomes, while T cells and NK cells displayed significantly less uptake.

Survivin: a unique target for tumor therapy

Survivin is the smallest member of the Inhibitor of apoptosis (IAP) family of proteins, involved in inhibition of apoptosis and regulation of cell cycle. These functional attributes make Survivin a unique protein exhibiting divergent functions i.e. regulating cell proliferation and cell death. Expression pattern of Survivin is also distinctive; it is prominently expressed during embryonal development, absent in most normal, terminally differentiated tissues but upregulated in a variety of human cancers. Expression of Survivin in tumours correlates with not only inhibition of apoptosis and a decreased rate of cell death, but also resistance to chemotherapy and aggressiveness of tumours. Therefore, Survivin is an important target for cancer vaccines and therapeutics. Survivin has also been found to be prominently expressed on both human and embryonic stem cells and many somatic stem cell types indicating its yet unexplored role in stem cell generation and maintenance. Overall, Survivin emerges as a molecule with much wider role in cellular homeostasis. This review will discuss various aspects of Survivin biology and its role in regulation of apoptosis, cell division, chemo-resistance and tumour progression. Various molecular and immunotherapeutic approaches targeting Survivin will also be discussed.

Endoplasmic Reticulum-resident Heat Shock Protein 90 (HSP90) Isoform Glucose-regulated Protein 94 (GRP94) Regulates Cell Polarity and Cancer Cell Migration by Affecting Intracellular Transport

Heat shock protein 90 (HSP90) is a molecular chaperone that is up-regulated in cancer and is required for the folding of numerous signaling proteins. Consequently, HSP90 represents an ideal target for the development of new anti-cancer agents. The human HSP90 isoform, glucose-regulated protein 94 (GRP94), resides in the endoplasmic reticulum and regulates secretory pathways, integrins, and Toll-like receptors, which contribute to regulating immunity and metastasis. However, the cellular function of GRP94 remains underinvestigated. We report that GRP94 knockdown cells are defective in intracellular transport and, consequently, negatively impact the trafficking of F-actin toward the cellular cortex, integrin α2 and integrin αL toward the cell membrane and filopodia, and secretory vesicles containing the HSP90α-AHA1-survivin complex toward the leading edge. As a result, GRP94 knockdown cells form a multipolar spindle instead of bipolar morphology and consequently manifest a defect in cell migration and adhesion.

Proteomic Profiling of Serum-Derived Exosomes from Ethnically Diverse Prostate Cancer Patients

Prostate cancer (PCa) remains the most frequently diagnosed male malignancy in Western countries and the second most common cause of male cancer death in the United States. The relatively elevated PCa incidence and mortality among African American men makes this cancer type a challenging health disparity disease. To increase the chance for successful trea tment, earlier detection and prediction of tumor aggress iveness will be important and need to be resolved. This study demonstrates that small membrane-bound vesicles shed from the tumor called exosomes contain ethnically and tumor-specific biomarkers, and could be exploited for their diagnostic and therapeutic potential.

Serum survivin predicts responses to treatment in active rheumatoid arthritis: a post hoc analysis from the SWEFOT trial

BACKGROUND

The identification of biomarkers that predict optimal and individual choices of treatment for patients with rheumatoid arthritis gains increasing attention. The purpose of this study was to investigate if the proto-oncogene survivin might aid in treatment decisions in early rheumatoid arthritis.

METHODS

Serum survivin levels were measured in 302 patients who completed the Swedish pharmacotherapy (SWEFOT) trial at baseline, 3, 12, and 24 months. Survivin levels > 0.45 ng/mL were considered positive. Based on the survivin status, core set outcomes measuring disease activity, functional disability, as well as global health and pain were evaluated after methotrexate (MTX) monotherapy at 3 months, and at 12 and 24 months of follow-up. Treatment of non-responders was randomly intensified with either a combination of disease-modifying antirheumatic drugs (triple therapy: MTX, sulfasalazine, and hydroxychloroquine) or by adding antibodies against tumor necrosis factor (anti-TNF).

RESULTS

Antirheumatic treatment resulted in an overall decrease of serum survivin levels. Survivin-positive patients at baseline who initially responded to MTX had a higher risk of disease re-activation (OR 3.21 (95% CI 1.12-9.24), P = 0.032) and failed to improve in their functional disability (P = 0.018) if having continued on MTX monotherapy compared to survivin-negative patients. Ever-smokers who were survivin-positive were less likely to respond to MTX than those who were survivin-negative (OR 1.91 (1.01-3.62), P = 0.045). In survivin-positive patients, triple therapy led to better improvements in disease activity than did MTX + anti-TNF. At 24 months, survivin-positive patients randomized to anti-TNF had a higher risk of active disease than those randomized to triple therapy (OR 3.15 (1.09-9.10), P = 0.037).

DISCUSSION

We demonstrate for the first time that survivin is a valuable serologic marker that can distinguish drug-specific clinical responses in early rheumatoid arthritis through the pragmatic clinical setting of the care-based SWEFOT trial. Although treatment response cannot solely be attributable to survivin status, per protocol sensitivity analyses confirmed the superior effect of triple therapy on survivin-positive patients.

CONCLUSIONS

Survivin-positive patients have poor outcomes if treated with MTX monotherapy. A decrease of survivin levels during treatment is associated with better clinical responses. For survivin-positive patients who fail MTX, triple therapy is associated with better outcomes than anti-TNF therapy.

TRIAL REGISTRATION

WHO database at the Karolinska University Hospital: CT20080004 ; ClinicalTrials.gov: NCT00764725, registered 1 October 2008.