HSP72 and gp96 in gastroenterological cancers

Differential Association of 4E-BP2-Interacting Proteins Is Related to Selective Delayed Neuronal Death after Ischemia

Cerebral ischemia induces an inhibition of protein synthesis and causes cell death and neuronal deficits. These deleterious effects do not occur in resilient areas of the brain, where protein synthesis is restored. In cellular stress conditions, as brain ischemia, translational repressors named eukaryotic initiation factor (eIF) 4E-binding proteins (4E-BPs) specifically bind to eIF4E and are critical in the translational control. We previously described that 4E-BP2 protein, highly expressed in brain, can be a molecular target for the control of cell death or survival in the reperfusion after ischemia in an animal model of transient cerebral ischemia. Since these previous studies showed that phosphorylation would not be the regulation that controls the binding of 4E-BP2 to eIF4E under ischemic stress, we decided to investigate the differential detection of 4E-BP2-interacting proteins in two brain regions with different vulnerability to ischemia-reperfusion (IR) in this animal model, to discover new potential 4E-BP2 modulators and biomarkers of cerebral ischemia. For this purpose, 4E-BP2 immunoprecipitates from the resistant cortical region and the vulnerable hippocampal cornu ammonis 1 (CA1) region were analyzed by two-dimensional (2-D) fluorescence difference in gel electrophoresis (DIGE), and after a biological variation analysis, 4E-BP2-interacting proteins were identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Interestingly, among the 4E-BP2-interacting proteins identified, heat shock 70 kDa protein-8 (HSC70), dihydropyrimidinase-related protein-2 (DRP2), enolase-1, ubiquitin carboxyl-terminal hydrolase isozyme-L1 (UCHL1), adenylate kinase isoenzyme-1 (ADK1), nucleoside diphosphate kinase-A (NDKA), and Rho GDP-dissociation inhibitor-1 (Rho-GDI), were of notable interest, showing significant differences in their association with 4E-BP2 between resistant and vulnerable regions to ischemic stress. Our data contributes to the first characterization of the 4E-BP2 interactome, increasing the knowledge in the molecular basis of the protection and vulnerability of the ischemic regions and opens the way to detect new biomarkers and therapeutic targets for diagnosis and treatment of cerebral ischemia.

The Serum and Saliva Proteome of Dogs with Diabetes Mellitus

This study aims to evaluate the changes in salivary and serum proteomes that occur in canine diabetes mellitus type-1 (DM) through a high-throughput quantitative proteomic analysis. The proteomes of 10 paired serum and saliva samples from healthy controls (HC group, n = 5) and dogs with untreated DM (DM group, n = 5) were analyzed using Tandem Mass Tags (TMT)-based proteomic approach. Additionally, 24 serum samples from healthy controls and untreated DM were used to validate haptoglobin in serum. The TMT analysis quantified 767 and 389 proteins in saliva and serum, respectively. Of those, 16 unique proteins in serum and 26 in saliva were differently represented between DM and HC groups. The verification of haptoglobin in serum was in concordance with the proteomic data. Our results pointed out changes in both saliva and serum proteomes that reflect different physiopathological changes in dogs with DM. Although some of the proteins identified here, such as malate dehydrogenase or glyceraldehyde-3-phosphate dehydrogenase, were previously related with DM in dogs, most of the proteins modulated in serum and saliva are described in canine DM for the first time and could be a source of potential biomarkers of the disease. Additionally, the molecular function, biological process, pathways and protein class of the differential proteins were revealed, which could improve the understanding of the disease's pathological mechanisms.

Identification of differentially expressed genes and biological pathways in para-carcinoma tissues of HCC with different metastatic potentials

Hepatocellular carcinoma (HCC) is a malignant tumor with extensive metastasis. Changes in the tumor microenvironment provide favorable conditions for tumor metastasis. However, the role of changes to the tumor microenvironment in HCC metastasis is yet to be elucidated. The Gene Expression Omnibus expression profile GSE5093 consists of 20 noncancerous tissues surrounding HCC tissues, including 9 metastasis-inclined microenvironment samples with detectable metastases and 11 metastasis-averse microenvironment samples without detectable metastases. The present study assessed 35 HCC samples to verify the results of chip analysis. In total, 712 upregulated and 459 downregulated genes were identified, with 1,033 nodes, 7,589 edges and 10 hub genes. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the differentially expressed genes were significantly enriched in ‘cell-cell adhesion’, ‘cell proliferation’ and ‘protein binding’. The top 10 hub genes were identified via a protein-protein interaction analysis. The 3 most significant modules were identified from the protein-protein network. Moreover, an association between hub genes and patient prognosis was identified. In conclusion, these candidate genes and pathways may help elucidate the mechanisms underlying HCC metastasis and identify more options for targeted therapy.

Melatonin suppresses senescence-derived mitochondrial dysfunction in mesenchymal stem cells via the HSPA1L-mitophagy pathway

Mesenchymal stem cells (MSCs) are a popular cell source for stem cell‐based therapy. However, continuous ex vivo expansion to acquire large amounts of MSCs for clinical study induces replicative senescence, causing decreased therapeutic efficacy in MSCs. To address this issue, we investigated the effect of melatonin on replicative senescence in MSCs. In senescent MSCs (late passage), replicative senescence decreased mitophagy by inhibiting mitofission, resulting in the augmentation of mitochondrial dysfunction. Treatment with melatonin rescued replicative senescence by enhancing mitophagy and mitochondrial function through upregulation of heat shock 70 kDa protein 1L (HSPA1L). More specifically, we found that melatonin‐induced HSPA1L binds to cellular prion protein (PrP^C), resulting in the recruitment of PrP^C into the mitochondria. The HSPA1L‐PrP^C complex then binds to COX4IA, which is a mitochondrial complex IV protein, leading to an increase in mitochondrial membrane potential and anti‐oxidant enzyme activity. These protective effects were blocked by knockdown of HSPA1L. In a murine hindlimb ischemia model, melatonin‐treated senescent MSCs enhanced functional recovery by increasing blood flow perfusion, limb salvage, and neovascularization. This study, for the first time, suggests that melatonin protects MSCs against replicative senescence during ex vivo expansion for clinical application via mitochondrial quality control.

Heat-shock proteins in diagnosis and treatment: an overview of different biochemical and immunological functions

Heat-shock proteins (HSPs) have been involved in different functions including chaperone activity, protein folding, apoptosis, autophagy and immunity. The HSP families have powerful effects on the stimulation of innate immune responses through Toll-like receptors and scavenger receptors. Moreover, HSP-mediated phagocytosis directly enhances the processing and presentation of internalized antigens via the endocytic pathway in adaptive immune system. These properties of HSPs have been used for development of prophylactic and therapeutic vaccines against infectious and noninfectious diseases. Several studies also demonstrated the relationship between HSPs and drug resistance as well as their use as a novel biomarker for detecting tumors in patients. The present review describes different roles of HSPs in biology and medicine especially biochemical and immunological aspects.

Isorhamnetin in Tsoong blocks Hsp70 expression to promote apoptosis of colon cancer cells

The roots of Codonopis bulleynana Forest ex diels (cbFed), locally known as Tsoong, have been used as a tonic food. Tsoong has wide range of pharmacological effects, including anticancer efficacy. In the present study, the anticancer activity of Tsoong and its potential molecular mechanisms were investigated. Isorhamnetin, a flavonol aglycone, is important compound and metabolite in Tsoong. It can promote apoptosis of colon cancer cells through up-regulating apoptosis-related genes (Apaf1, Casp3 and Casp9) because it blocks Hsp70 genes (Hspa1a, Hspa1b and Hspa8). These were verified by in vitro and in vivo experiments. In vitro, cell counting kit-8 (CCK-8) assays and flow cytometry in HCT116 and SW480 colon cancer cell were used to assess the anti-proliferation and apoptosis-promoting activities of Tsoong. In vivo, the antitumor effect of Tsoong was assessed in colon cancer-bearing nude mice as a xenograft model. These results show that Isorhamnetin is very critical in Tsoong because Tsoong can down-regulate Hsp70 genes and promote apoptosis of colon cancer cells by inhibiting Hsp70 largely due to the efficacy of Isorhamnetin. Our results may ultimately help in the development of diagnostic and therapeutic strategies to control this devastating disease.

Development of a Novel Nonradioisotopic Assay and Cdc25B Overexpression Cell Lines for Use in Screening for Cdc25B Inhibitors

PURPOSE

The cyclin-dependent kinase 1 (Cdk1) and cyclin B complex performs important roles in the transition from the G2 to M phase in the cell cycle through removal of inhibitory phosphates on Cdk1, and Cdc25B, which is a dual-specific phosphatase, mediates these dephosphorylation events. However, measuring Cdc25B activity by existing methods is hampered by inadequate nonspecific substrates and the need to use a radiolabeled isotope. The present study aimed to develop an improved method with which to properly measure Cdc25B activity using a novel nonradioisotopic assay and Cdc25B overexpression cell lines.

MATERIALS AND METHODS

A nonradioisotopic Cdk1 kinase assay, based on Western blotting for retinoblastoma protein and histone H1, was used to analyze Cdc25B activity. Also, stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines were constructed using the tetracycline-regulated expression system and were applied as a tool for screening for inhibitors of Cdc25B.

RESULTS

The present study developed and optimized a nonradioisotopic assay method to properly measure Cdc25B activity. Furthermore, we constructed stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines for the establishment of a strong assay system with which to evaluate the specificity of Cdc25B inhibitors under conditions similar to the intracellular environment. These methods were confirmed as useful tools for measuring Cdc25B activity.

CONCLUSION

The nonradioisotopic Cdk1 kinase assay and Cdc25B overexpression cell lines developed in this study can be conveniently used as tools for screening inhibitors of Cdc25B phosphatase as anticancer drugs.

Alpha-Fetoprotein and Hepatocellular Carcinoma Immunity

Hepatocarcinoma is one of the most prevalent gastroenterological cancers in the world with less effective therapy. As an oncofetal antigen and diagnostic marker for liver cancer, alpha-fetoprotein (AFP) possesses a variety of biological functions. Except for its diagnosis in liver cancer, AFP has become a target for liver cancer immunotherapy. Although the immunogenicity of AFP is weak and it could induce the immune escapes through inhibiting the function of dendritic cells, natural killer cells, and T lymphocytes, AFP has attracted more attention in liver cancer immunotherapy. By in vitro modification, the immunogenicity and immune response of AFP could be enhanced. AFP-modified immune cell vaccine or peptide vaccine has displayed the specific antitumor immunity against AFP-positive tumor cells and laid a better foundation for the immunotherapy of liver cancer.

Glucose-regulated protein 94 mediates progression and metastasis of esophageal squamous cell carcinoma via mitochondrial function and the NF-kB/COX-2/VEGF axis

Esophageal cancer is a worldwide health problem with a very poor prognosis. Therefore, new diagnostic biomarkers or therapeutic strategies for identifying and managing esophageal squamous cell carcinoma (ESCC) are urgently needed. Glucose-regulated protein 94 (GRP94) is one of major endoplasmic reticulum-stress response proteins that plays a key role in cancer progression and therapeutic responses. However, the role of GRP94 in ESCC progression and metastasis remains unclear. The tissue array results indicated that higher GRP94 expression levels were associated with lower overall survival and higher lympho-node metastasis. Silencing GRP94 (GRP94-KD) reduced cell proliferation, migration and invasion in ESCC cells. In a xenotransplantation assay, silencing GRP94 reduced cell proliferation in the zebrafish embryo. Transmission electron microscopy revealed impaired mitochondria in GRP94-KD cells, which exhibited reduced basal respiration, spare respiratory capacity and ATP production and increased oxidative damage compared with scrambled control cells. Regarding the molecular mechanism underlying the effects of GRP94 knockdown, we found that silencing GRP94 may reduce the level of NF-kB, c-Jun, p38, IL-6, vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) as well as activation of AKT and ERK. In conclusion, our results indicate that silencing GRP94 in ESCC cells suppressed cancer growth and the metastatic potential via mitochondrial functions and NF-kB/COX-2/VEGF in ESCC cells.

Autophagy: An overview and its roles in cancer and obesity

Autophagy is a normal physiological process necessary for cellular homeostasis to maintain adequate levels of cellular components. It is essential to stabilize the source of energy during development and nutritional stress and plays the dual role of survival or cell killing in various diseases including cancer. The selectivity of the response to removal of selected organelles may vary according to the each type. Macroautophagy forms a double-membraned autophagosome around the organelle destined for processing. Microautophagy involves direct engulfment of the cellular components by lysosomal invagination. Chaperone mediated autophagy (CMA) is highly selective and is dependent on the chaperone hsc70 for its activity. The effects of all these types are implemented by autophagy related genes. In this review, the markers, activators, inhibitors biological effects and roles of the three classes of autophagy in cancer and obesity are discussed.