Curcumin affects HSP60 folding activity and levels in neuroblastoma cells

The fundamental challenge in fighting cancer is the development of protective agents able to interfere with the classical pathways of malignant transformation, such as extracellular matrix remodeling, epithelial\u2013mesenchymal transition and, alteration of protein homeostasis. In the tumors of the brain, proteotoxic stress represents one of the main triggering agents for cell transformation. Curcumin is a natural compound with anti-inflammatory and anti-cancer properties with promising potential for the development of therapeutic drugs for the treatment of cancer as well as neurodegenerative diseases. Among the mediators of cancer development, HSP60 is a key factor for the maintenance of protein homeostasis and cell survival. High HSP60 levels were correlated, in particular, with cancer development and progression, and for this reason, we investigated the ability of curcumin to affect HSP60 expression, localization, and post-translational modifications using a neuroblastoma cell line. We have also looked at the ability of curcumin to interfere with the HSP60/HSP10 folding machinery. The cells were treated with 6, 12.5, and 25 \ub5M of curcumin for 24 h, and the flow cytometry analysis showed that the compound induced apoptosis in a dose-dependent manner with a higher percentage of apoptotic cells at 25 \ub5M. This dose of curcumin-induced a decrease in HSP60 protein levels and an upregulation of HSP60 mRNA expression. Moreover, 25 \ub5M of curcumin reduced HSP60 ubiquitination and nitration, and the chaperonin levels were higher in the culture media compared with the untreated cells. Furthermore, curcumin at the same dose was able to favor HSP60 folding activity. The reduction of HSP60 levels, together with the increase in its folding activity and the secretion in the media led to the supposition that curcumin might interfere with cancer progression with a protective mechanism involving the chaperonin

Exosome levels in human body fluids: A tumor marker by themselves?

Despite considerable research efforts, the finding of reliable tumor biomarkers remains challenging and unresolved. In recent years a novel diagnostic biomedical tool with high potential has been identified in extracellular nanovesicles or exosomes. They are released by the majority of the cells and contain detailed molecular information on the cell of origin including tumor hallmarks. Exosomes can be isolated from easy accessible body fluids, and most importantly, they can provide several biomarkers, with different levels of specificity. Recent clinical evidence shows that the levels of exosomes released into body fluids may themselves represent a predictive/diagnostic of tumors, discriminating cancer patients from healthy subjects. The aim of this review is to highlight these latest challenging findings to provide novel and groundbreaking ideas for successful tumor early diagnosis and follow-up

EXOSOMES: CAN DOCTORS STILL IGNORE THEIR EXISTENCE?

With this invited commentary we want to draw the attention of young medical doctors, the main readers of this journal, towards the existence and importance of a group of nanovesicles released by human cells: the exosomes. These vesicles are incontinently se-creted as a mean of cell-to-cell communication. They are involved in a number of physiol-ogic processes as well as in the pathogenesis of, virtually, all human diseases. They can be isolated from all biological fluids, like blood, urine, sweat, sperm, crevicular fluid, bile, etc., and their composition in terms of proteins, RNA and lipids is different in pathology that in physiologic conditions. It is therefore possible to predict that they will become an important diagnostic and therapeutic tool in medicine

Functions and Therapeutic Potential of Extracellular Hsp60, Hsp70, and Hsp90 in Neuroinflammatory Disorders

Neuroinflammation is implicated in central nervous system (CNS) diseases, but the molecular mechanisms involved are poorly understood. Progress may be accelerated by developing a comprehensive view of the pathogenesis of CNS disorders, including the immune and the chaperone systems (IS and CS). The latter consists of the molecular chaperones; cochaperones; and chaperone cofactors, interactors, and receptors of an organism and its main collaborators in maintaining protein homeostasis (canonical function) are the ubiquitin-proteasome system and chaperone-mediated autophagy. The CS has also noncanonical functions, for instance, modulation of the IS with induction of proinflammatory cytokines. This deserves investigation because it may be at the core of neuroinflammation, and elucidation of its mechanism will open roads toward developing efficacious treatments centered on molecular chaperones (i.e., chaperonotherapy). Here, we discuss information available on the role of three members of the CS-heat shock protein (Hsp)60, Hsp70, and Hsp90-in IS modulation and neuroinflammation. These three chaperones occur intra- and extracellularly, with the latter being the most likely involved in neuroinflammation because they can interact with the IS. We discuss some of the interactions, their consequences, and the molecules involved but many aspects are still incompletely elucidated, and we hope that this review will encourage research based on the data presented to pave the way for the development of chaperonotherapy. This may consist of blocking a chaperone that promotes destructive neuroinflammation or replacing or boosting a defective chaperone with cytoprotective activity against neurodegeneration

The challenging riddle about the janus‐type role of hsp60 and related extracellular vesicles and miRNAs in carcinogenesis and the promises of its solution

Hsp60 is one of the most ancient and evolutionarily conserved members of the chaperoning system. It typically resides within mitochondria, in which it contributes to maintaining the organelle’s proteome integrity and homeostasis. In the last few years, it has been shown that Hsp60 also occurs in other locations, intracellularly and extracellularly, including cytosol, plasmacell membrane, and extracellular vesicles (EVs). Consequently, non‐canonical functions and interacting partners of Hsp60 have been identified and it has been realized that it is a hub molecule in diverse networks and pathways and that it is implicated, directly or indirectly, in the development of various pathological conditions, the Hsp60 chaperonopathies. In this review, we will focus on the multi‐faceted role of this chaperonin in human cancers, showing the contribution of intra‐ and extracellular Hsp60 in cancer development and progression, as well as the impact of miRNA‐mediated regulation of Hsp60 in carcinogenesis. There are still various aspects of this intricate biological scenario that are poorly understood but ongoing research is steadily providing new insights and we will direct attention to them. For instance, we will highlight the possible applications of the Hsp60 involvement in carcinogenesis not only in diagnosis, but also in the development of specific anti‐cancer therapies centered on the use of the chaperonin as therapeutic target or agent and depending on its role, pro‐ or anti‐tumor

Hsp60 Post-translational Modifications: Functional and Pathological Consequences

Hsp60 is a chaperone belonging to the Chaperonins of Group I and typically functions inside mitochondria in which, together with the co-chaperonin Hsp10, maintains protein homeostasis. In addition to this canonical role, Hsp60 plays many others beyond the mitochondria, for instance in the cytosol, plasma-cell membrane, extracellular space, and body fluids. These non-canonical functions include participation in inflammation, autoimmunity, carcinogenesis, cell replication, and other cellular events in health and disease. Thus, Hsp60 is a multifaceted molecule with a wide range of cellular and tissue locations and functions, which is noteworthy because there is only one hsp60 gene. The question is by what mechanism this protein can become multifaceted. Likely, one factor contributing to this diversity is post-translational modification (PTM). The amino acid sequence of Hsp60 contains many potential phosphorylation sites, and other PTMs are possible such as O-GlcNAcylation, nitration, acetylation, S-nitrosylation, citrullination, oxidation, and ubiquitination. The effect of some of these PTMs on Hsp60 functions have been examined, for instance phosphorylation has been implicated in sperm capacitation, docking of H2B and microtubule-associated proteins, mitochondrial dysfunction, tumor invasiveness, and delay or facilitation of apoptosis. Nitration was found to affect the stability of the mitochondrial permeability transition pore, to inhibit folding ability, and to perturb insulin secretion. Hyperacetylation was associated with mitochondrial failure; S-nitrosylation has an impact on mitochondrial stability and endothelial integrity; citrullination can be pro-apoptotic; oxidation has a role in the response to cellular injury and in cell migration; and ubiquitination regulates interaction with the ubiquitin-proteasome system. Future research ought to determine which PTM causes which variations in the Hsp60 molecular properties and functions, and which of them are pathogenic, causing chaperonopathies. This is an important topic considering the number of acquired Hsp60 chaperonopathies already cataloged, many of which are serious diseases without efficacious treatment

The triad hsp60-mirnas-extracellular vesicles in brain tumors: Assessing its components for understanding tumorigenesis and monitoring patients

Brain tumors have a poor prognosis and progress must be made for developing efficacious treatments, but for this to occur their biology and interaction with the host must be elucidated beyond current knowledge. What has been learned from other tumors may be applied to study brain tumors, for example, the role of Hsp60, miRNAs, and extracellular vesicles (EVs) in the mechanisms of cell proliferation and dissemination, and resistance to immune attack and anticancer drugs. It has been established that Hsp60 increases in cancer cells, in which it occurs not only in the mitochondria but also in the cytosol and plasma-cell membrane and it is released in EVs into the extracellular space and in circulation. There is evidence suggesting that these EVs interact with cells near and far from their original cell and that this interaction has an impact on the functions of the target cell. It is assumed that this crosstalk between cancer and host cells favors carcinogenesis in various ways. We, therefore, propose to study the triad Hsp60-related miRNAs-EVs in brain tumors and have standardized methods for the purpose. These revealed that EVs with Hsp60 and related miRNAs increase in patients’ blood in a manner that reflects disease status. The means are now available to monitor brain tumor patients by measuring the triad and to dissect its effects on target cells in vitro, and in experimental models in vivo

Doxorubicin anti-tumor mechanisms include Hsp60 post-translational modifications leading to the Hsp60/p53 complex dissociation and instauration of replicative senescence

The chaperone Hsp60 is pro-carcinogenic in certain tumor types by interfering with apoptosis and with tumor cell death. In these tumors, it is not yet known whether doxorubicin anti-tumor effects include a blockage of the pro-carcinogenic action of Hsp60. We found a doxorubicin dose-dependent viability reduction in a human lung mucoepidermoid cell line that was paralleled by the appearance of cell senescence markers. Concomitantly, intracellular Hsp60 levels decreased while its acetylation levels increased. The data suggest that Hsp60 acetylation interferes with the formation of the Hsp60/p53 complex and/or promote its dissociation, both causing an increase in the levels of free p53, which can then activate the p53-dependent pathway toward cell senescence. On the other hand, acetylated Hsp60 is ubiquitinated and degraded and, thus, the anti-apoptotic effect of the chaperonin is abolished with subsequent tumor cell death. Our findings could help in the elucidation of the molecular mechanisms by which doxorubicin counteracts carcinogenesis and, consequently, it would open new roads for the development of cancer treatment protocols targeting Hsp60

Study of the effects of Pleurotuseryngii var. eryngii on heat shock proteins and cytokines levels in a mouse model of colon carcinoma

Medicinal mushrooms are wonderful source of nutraceuticals with a wide range of benefit for human health. The current anti-cancer therapy is not always target specific and often is associated with complications for patients. Therefore new effective and less toxic therapeutic approaches are needed. Heat shock proteins (Hsps) are highly expressed in a variety of cancer types contributing to tumor cell propagation. Here, we treated C26 colon cancer cells with a cold-water extracts of an edible mushrooms Pleurotuseryngii var. eryngii (Pleuery). Hsp90, 70, 60 and 27 levels were measured by western blotting and immunofluorescence analysis. Moreover, we evaluated Pleueryanti cancer effect in an animal model of ectopically-implanted C26 colon carcinoma. We prepared a mixture of lyophilized Pleuery with the mice standard diet, and the animals were daily fed with ~4g of the mix, 10 days before tumor implantation and until they died to draw a survival curve. A control group of mice fed with the standard diet, was used as control. We performed immunofluorescence and western blotting analysis for Hsps in the explanted tumors. Our results, showed that the extract affected cells viability at 0.5 \ub5g/\ub5l after both at 24 and 48 hours of treatments. Western blotting analysis of the cells lysate showed no changes in the Hsps protein levels except for Hsp60 which levels decreased at 24h of treatment but increased after 48h. Pleuery in the diet significantly extended the median survival compared to untreated mice. Moreover, western blotting analysis and immunofluorescence of the allograft tumors showed the decrease of Hsp90, 70 and Hsp60 levels while Hsp27 levels increased. Finally, qRT-PCR showed the down-regulation of IL-1 and IL-6 expression levels while the expression levels of TNF\u3b1 did not changed. These results led us to suppose the antioxidant and anti-inflammatory effects of Pleuery in vivo

The chaperone system in glioblastoma multiforme and derived cell lines: diagnostic and mechanistic implications

BACKGROUND: Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumor in adults. Novel treatments are needed to counteract the molecular mechanisms of GBM growth and drug resistance. The chaperone system (CS) members are typically cytoprotective but some, termed Hsp, can become pathogenic and participate in carcinogenesis, along with the vascular endothelial growth factor (VEGF), and we investigated them in GBM biopsies and derived cell lines. The objectives were to identify diagnostic-prognostic biomarkers and gather information for developing chaperonotherapy. METHODS: Cell lines from GBMs were established, characterized (morphology, growth characteristics, and specific markers), and stored. Chaperones and angiogenic factors [Hsp10, Hsp27, Hsp60, Hsp70, Hsp90, FLT-1 (VEGFR-1), FLK1 (KDR, VEGFR-2), and FLT-4 (VEGFR-3)] were observed in cells by immunofluorescence while the chaperones were measured in tumor tissue by immunohistochemistry. RESULTS: Four cell lines were derived from four different GBMs; the cells were spindle shaped or polygonal and grew at high rates as adherent monolayers or clusters without evidence of contact inhibition. The astrocyte-specific glial fibrillary acidic protein (GFAP); and the neuronal NSE, malignancy VIM, and proliferation PCNA, markers were determined. The cells expressed GFAP but no NSE, indicating that they were primary glioblastoma cell lines, with high levels of Hsp10, Hsp27, Hsp60, Hsp90, and Flk1; and low levels of Hsp70, Flt1, and Flt4. CONCLUSIONS: Four cell lines were established derived from four out of ten GBM tumors studied. The cell lines showed intense positivity for chaperones studied and factors connected to malignancy and the tumors showed increased levels of chaperones, making them potential diagnostic-prognostic biomarkers and targets for anti-cancer compounds