Facets of heat shock protein 70 show immunotherapeutic potential

HIKESHI silencing can enhance mild hyperthermia sensitivity in human oral squamous cell carcinoma HSC‑3 cells

Hyperthermia (HT) is considered to be of value as a treatment modality in various cancers. However, the acquisition of thermotolerance in cancer cells due to the induction of heat shock proteins (HSPs) makes HT less effective. Recent findings have indicated that heat shock protein nuclear import factor hikeshi (HIKESHI), also referred to as C11orf73, acts as a nuclear import carrier of Hsp70 under heat stress conditions. The aim of the present study was to determine whether knockdown (KD) of HIKESHI by small interfering RNA (siRNA) can potentiate mild HT (MHT) sensitivity in human oral squamous cell carcinoma (OSCC) HSC‑3 cells. The mRNA and protein expression of HIKESHI was found to be markedly suppressed in HSC‑3 cells treated with siRNA for HIKESHI (siHIKE). Silencing HIKESHI significantly decreased the cell viability under MHT conditions (42˚C for 90 min). Immunocytochemical and western blot analyses clearly demonstrated that Hsp70 protein translocated from the cytoplasm to the nucleus under MHT conditions, and this translocation was significantly inhibited in cells treated with siHIKE. Treatment of the cells with MHT transiently increased the phosphorylation level of extracellular signal‑regulated kinase (ERK)2. Furthermore, the phosphorylation was sustained in HIKESHI‑KD cells under MHT conditions, and this sustained phosphorylation was abolished by pretreatment with U0126, an inhibitor of mitogen‑activated protein kinase/ERK. In addition, U0126 significantly decreased the viability of cells treated with the combination of HIKESHI‑KD and MHT. The data of the present study suggest that HIKESHI silencing enhanced the sensitivity of human OSCC HSC‑3 cells to MHT.

HER2-Positive Breast Cancer Immunotherapy: A Focus on Vaccine Development

Clinical progress in the field of HER2-positive breast cancer therapy has been dramatically improved by understanding of the immune regulatory mechanisms of tumor microenvironment. Passive immunotherapy utilizing recombinant monoclonal antibodies (mAbs), particularly trastuzumab and pertuzumab has proved to be an effective strategy in HER2-positive breast cancer treatment. However, resistance to mAb therapy and relapse of disease are still considered important challenges in clinical practice. There are increasing reports on the induction of cellular and humoral immune responses in HER2-positive breast cancer patients. More recently, increasing efforts are focused on using HER2-derived peptide vaccines for active immunotherapy. Here, we discuss the development of various HER2-derived vaccines tested in animal models and human clinical trials. Different formulations and strategies to improve immunogenicity of the antigens in animal studies are also discussed. Furthermore, other immunotherapeutic approaches to HER2 breast cancer including, CTLA-4 inhibitors, immune checkpoint inhibitors, anti PD-1/PD-L1 antibodies are presented.

HSP70: an alarmin that does not induce high rates of preterm birth but does cause adverse neonatal outcomes

Objective: Preterm labor and birth are strongly associated with sterile intra-amniotic inflammation, a clinical condition that is proposed to be initiated by danger signals, or alarmins. The aim of this study was to investigate whether the intra-amniotic administration of the alarmin heat shock protein 70 (HSP70) induces preterm labor/birth and adverse neonatal outcomes.Methods: Pregnant mice received an intra-amniotic injection of 200 ng (n = 8), 400 ng (n = 6), 500 ng (n = 10), or 1 µg of HSP70 (n = 6). Control mice were injected with saline (n = 10). Following injection, the rates of preterm labor/birth and neonatal mortality were recorded. Neonatal weights at weeks 1, 2, and 3 were also recorded.Results: The intra-amniotic injection of 400 ng [late preterm birth 16.7 ± 16.7% (1/6)], 500 ng [early and late preterm birth 10 ± 10% (1/10) each], or 1 µg [early preterm birth 16.7 ± 16.7% (1/6)] of HSP70 induced low rates of preterm/birth. However, the intra-amniotic injection of 500 ng or 1 µg of HSP70 induced significantly higher rates of neonatal mortality compared to controls [saline 14.2% (10/74), 200 ng 9.8% (6/61), 400 ng 17.9% (9/45), 500 ng 28.8% (23/78), and 1 µg 21.4% (13/49)]. Neonates born to dams injected with 200, 500 ng, or 1 µg HSP70 were leaner than controls (p ≤ .05).Conclusion: Intra-amniotic administration of the alarmin HSP70 did not induce high rates of preterm labor/birth; yet, it did indeed result in adverse neonatal outcomes.

Early Proteome Shift and Serum Bioactivity Precede Diesel Exhaust-induced Impairment of Cardiovascular Recovery in Spontaneously Hypertensive Rats

Single circulating factors are often investigated to explain air pollution-induced cardiovascular dysfunction, yet broader examinations of the identity and bioactivity of the entire circulating milieu remain understudied. The purpose of this study was to determine if exposure-induced cardiovascular dysfunction can be coupled with alterations in both serum bioactivity and the circulating proteome. Two cohorts of Spontaneously Hypertensive Rats (SHRs) were exposed to 150 or 500 μg/m³ diesel exhaust (DE) or filtered air (FA). In Cohort 1, we collected serum 1 hour after exposure for proteomics analysis and bioactivity measurements in rat aortic endothelial cells (RAECs). In Cohort 2, we assessed left ventricular pressure (LVP) during stimulation and recovery from the sympathomimetic dobutamine HCl, one day after exposure. Serum from DE-exposed rats had significant changes in 66 serum proteins and caused decreased NOS activity and increased VCAM-1 expression in RAECs. While rats exposed to DE demonstrated increased heart rate at the start of LVP assessments, heart rate, systolic pressure, and double product fell below baseline in DE-exposed rats compared to FA during recovery from dobutamine, indicating dysregulation of post-exertional cardiovascular function. Taken together, a complex and bioactive circulating milieu may underlie air pollution-induced cardiovascular dysfunction.

CD20+ Tumor Infiltrating B Lymphocyte in Oral Squamous Cell Carcinoma: Correlation with Clinicopathologic Characteristics and Heat Shock Protein 70 Expression

Objective

B lymphocyte infiltration in the tumor microenvironment has been proposed to play pivotal roles in tumor progression. Heat shock protein 70 (HSP70) expressed by tumor cells can induce antitumor immune response. Few studies have examined the clinicopathologic relationship between tumor infiltrating B lymphocyte and HSP70 expression in human cancer. So far, there is no complete knowledge on the relationship in oral squamous cell carcinoma (OSCC). The present study was conducted to evaluate the relationship between tumor infiltrating B lymphocyte and HSP70 expression in OSCC, as well as the clinical outcome.

Materials and Methods

In this retrospective study, the immunohistochemical analysis of 50 OSCC specimens was performed using CD20 and HSP70 antibodies. The relationship between markers' expression and clinicopathologic data was evaluated using Mann–Whitney test, Chi-square test, logistic regression model, and Spearman's correlation coefficient.

Results

The data analysis showed significant correlation between peritumoral CD20⁺ B lymphocyte infiltration and lymph node metastasis (P = 0.047). Furthermore, HSP70 expression was significantly correlated with stage (P = 0.003), lymph node metastasis (P < 0.001), and tumor size (P = 0.044). However, no relationship was observed between B lymphocyte infiltration and HSP70 expression.

Conclusion

The results suggest that peritumoral B lymphocyte infiltration and HSP70 expression level have significant association with OSCC and may be considered as prognostic indicators in OSCC. Thus, evaluation of B cells as therapeutic targets in OSCC patients is recommended.

Focused ultrasound for immuno-adjuvant treatment of pancreatic cancer: An emerging clinical paradigm in the era of personalized oncotherapy

Current clinical treatment regimens, including many emergent immune strategies (e.g., checkpoint inhibitors) have done little to affect the devastating course of pancreatic ductal adenocarcinoma (PDA). Clinical trials for PDA often employ multi-modal treatment, and have started to incorporate stromal-targeted therapies, which have shown promising results in early reports. Focused ultrasound (FUS) is one such therapy that is uniquely equipped to address local and systemic limitations of conventional cancer therapies as well as emergent immune therapies for PDA. FUS methods can non-invasively generate mechanical and/or thermal effects that capitalize on the unique oncogenomic/proteomic signature of a tumor. Potential benefits of FUS therapy for PDA include: (1) emulsification of targeted tumor into undenatured antigens in situ, increasing dendritic cell maturation, and increasing intra-tumoral CD8+/ T regulatory cell ratio and CD8+ T cell activity; (2) reduction in intra-tumoral hypoxic stress; (3) modulation of tumor cell membrane protein localization to enhance immunogenicity; (4) modulation of the local cytokine milieu toward a Th1-type inflammatory profile; (5) up-regulation of local chemoattractants; (6) remodeling the tumor stroma; (7) localized delivery of exogenously packaged immune-stimulating antigens, genes and therapeutic drugs. While not all of these results have been studied in experimental PDA models to date, the principles garnered from other solid tumor and disease models have direct relevance to the design of optimal FUS protocols for PDA. In this review, we address the pertinent limitations in current and emergent immune therapies that can be improved with FUS therapy for PDA.

Role of the Immune System in Hypertension

High blood pressure is present in more than one billion adults worldwide and is the most important modifiable risk factor of death resulting from cardiovascular disease. While many factors contribute to the pathogenesis of hypertension, a role of the immune system has been firmly established by a large number of investigations from many laboratories around the world. Immunosuppressive drugs and inhibition of individual cytokines prevent or ameliorate experimental hypertension, and studies in genetically-modified mouse strains have demonstrated that lymphocytes are necessary participants in the development of hypertension and in hypertensive organ injury. Furthermore, immune reactivity may be the driving force of hypertension in autoimmune diseases. Infiltration of immune cells, oxidative stress, and stimulation of the intrarenal angiotensin system are induced by activation of the innate and adaptive immunity. High blood pressure results from the combined effects of inflammation-induced impairment in the pressure natriuresis relationship, dysfunctional vascular relaxation, and overactivity of the sympathetic nervous system. Imbalances between proinflammatory effector responses and anti-inflammatory responses of regulatory T cells to a large extent determine the severity of inflammation. Experimental and human studies have uncovered autoantigens (isoketal-modified proteins and heat shock protein 70) of potential clinical relevance. Further investigations on the immune reactivity in hypertension may result in the identification of new strategies for the treatment of the disease.

Heat shock proteins and their immunomodulatory role in inflammatory arthritis

Autoimmune diseases, including inflammatory arthritis, are characterized by a loss of self-tolerance, leading to an excessive immune responses and subsequent ongoing inflammation. Current therapies are focused on dampening this inflammation, but a permanent state of tolerance is seldom achieved. Therefore, novel therapies that restore and maintain tolerance are needed. Tregs could be a potential target to achieve permanent immunotolerance. Activation of Tregs can be accomplished when they recognize and bind their specific antigens. HSPs are proteins present in all cells and are upregulated during inflammation. These proteins are immunogenic and can be recognized by Tregs. Several studies in animal models and in human clinical trials have shown the immunoregulatory effects of HSPs and their protective effects in inflammatory arthritis. In this review, an overview is presented of the immunomodulatory effects of several members of the HSP family in general and in inflammatory arthritis. These effects can be attributed to the activation of Tregs through cellular interactions within the immune system. The effect of HSP-specific therapies in patients with inflammatory arthritis should be explored further, especially with regard to long-term efficacy and safety and their use in combination with current therapeutic approaches.

Priming the immune system of Penaeid shrimp by bacterial HSP70 (DnaK)

This study was conducted to test the effect of DnaK on priming immune responses in Penaeid shrimp. Juvenile-specific pathogen-free (SPF) P. vannamei shrimp were injected with 0.05 μg recombinant DnaK. One hour post-DnaK priming, a non-lethal dose of Vibrio campbellii (10(5) CFU shrimp(-1)) was injected. Other treatments include only DnaK or V. campbellii injection or control with blank inocula. The haemolymph of three shrimp from each treatment was collected at 1.5, 6, 9 and 12 h post-DnaK priming (hpp). It was verified that injection with DnaK and V. campbellii challenge affected the transcription of 3 immune genes, transglutaminase-1 (TGase-1), prophenoloxidase-2 (proPO-2) and endogenous HSP70 (lvHSP70). In P. monodon, shrimp were first injected with DnaK at a dose of 10 μg shrimp(-1) and one hour later with 10(6) CFU of V. harveyi (BB120) shrimp(-1). Shrimp injected with DnaK showed a significant increase in proPO expression compared to the control (P < 0.05). Yet a double injection (DnaK and Vibrio) seemed to cause an antagonistic response at the level of expression, which was not equalled at the level of PO activity. Those results suggest that DnaK is able to modulate immune responses in P. vannamei and P. monodon.

Focused ultrasound-aided immunomodulation in glioblastoma multiforme: a therapeutic concept

Patients with glioblastoma multiforme (GBM) exhibit a deficient anti-tumor immune response. Both arms of the immune system were shown to be hampered in GBM, namely the local cellular immunity mediated by the Th₁ subset of helper T cells and the systemic humoral immunity mediated by the Th₂ subset of helper T cells. Immunotherapy is rapidly becoming one of the pillars of anti-cancer therapy. GBM has not received similar clinical successes as of yet, which may be attributed to its relative inaccessibility (the blood-brain barrier (BBB)), its poor immunogenicity, few characterized cancer antigens, or any of the many other immune mechanisms known to be hampered. Focused ultrasound (FUS) is emerging as a promising treatment approach. The effects of FUS on the tissue are not merely thermal. Mounting evidence suggests that in addition to thermal ablation, FUS induces mechanical acoustic cavitation and immunomodulation plays a key role in boosting the host anti-tumor immune responses. We separately discuss the different pertinent immunosuppressive mechanisms harnessed by GBM and the immunomodulatory effects of FUS. The effect of FUS and microbubbles in disrupting the BBB and introducing antigens and drugs to the tumor milieu is discussed. The FUS-induced pro-inflammatory cytokines secretion and stress response, the FUS-induced change in the intra-tumoral immune-cells populations, the FUS-induced augmentation of dendritic cells activity, and the FUS-induced increased cytotoxic cells potency are all discussed. We next attempt at offering a conceptual synopsis of the synergistic treatment of GBM utilizing FUS and immunotherapy. In conclusion, it is increasingly apparent that no single treatment modality will triumph on GBM. The reviewed FUS-induced immunomodulation effects can be harnessed to current and developing immunotherapy approaches. Together, these may overcome GBM-induced immune-evasion and generate a clinically relevant anti-tumor immune response.

Kill and spread the word: stimulation of antitumor immune responses in the context of radiotherapy

Besides the direct, targeted effects of ionizing irradiation (x-ray) on cancer cells, namely DNA damage and cell death induction, indirect, nontargeted ones exist, which are mediated in large part by the immune system. Immunogenic forms of tumor cell death induced by x-ray, including immune modulating danger signals like the heat shock protein 70, adenosine triphosphate, and high-mobility group box 1 protein are presented. Further, antitumor effects exerted by cells of the innate (natural killer cells) as well as adaptive immune system (T cells activated by dendritic cells) are outlined. Tumor cell death inhibiting molecules such as survivin are introduced as suitable target for molecularly tailored therapies in combination with x-ray. Finally, reasonable combinations of immune therapies with radiotherapy are discussed.

Enhanced bleaching treatment: opportunities for immune-assisted melanocyte suicide in vitiligo

Depigmentation in vitiligo occurs by progressive loss of melanocytes from the basal layer of the skin, and can be psychologically devastating to patients. T cell-mediated autoimmunity explains the progressive nature of this disease. Rather than being confronted with periods of rapid depigmentation and bouts of repigmentation, patients with long-standing, treatment-resistant vitiligo can undergo depigmentation treatment. The objective is to remove residual pigmentation to achieve a cosmetically acceptable result--that of skin with a uniform appearance. In the United States, only the use of mono-benzyl ether of hydroquinone (MBEH) is approved for this purpose. However, satisfactory results can take time to appear, and there is a risk of repigmentation. MBEH induces necrotic melanocyte death followed by a cytotoxic T-cell response to remaining, distant melanocytes. As cytotoxic T-cell responses are instrumental to depigmentation, we propose that combining MBEH with immune adjuvant therapies will accelerate immune-mediated melanocyte destruction to achieve faster, more definitive depigmentation than with MBEH alone. As Toll-like Receptor (TLR) agonists--imiquimod, CpG, and Heat Shock Protein 70 (HSP 70)--all support powerful Th1 responses, we propose that using MBEH in combination with these agents can achieve superior depigmentation results for vitiligo patients.

Heat shock protein 70 enhances mucosal immunity against human norovirus when coexpressed from a vesicular stomatitis virus vector

Human norovirus (NoV) accounts for 95% of nonbacterial gastroenteritis worldwide. Currently, there is no vaccine available to combat human NoV as it is not cultivable and lacks a small-animal model. Recently, we demonstrated that recombinant vesicular stomatitis virus (rVSV) expressing human NoV capsid protein (rVSV-VP1) induced strong immunities in mice (Y. Ma and J. Li, J. Virol. 85:2942-2952, 2011). To further improve the safety and efficacy of the vaccine candidate, heat shock protein 70 (HSP70) was inserted into the rVSV-VP1 backbone vector. A second construct was generated in which the firefly luciferase (Luc) gene was inserted in place of HSP70 as a control for the double insertion. The resultant recombinant viruses (rVSV-HSP70-VP1 and rVSV-Luc-VP1) were significantly more attenuated in cell culture and viral spread in mice than rVSV-VP1. At the inoculation dose of 1.0 × 10(6) PFU, rVSV-HSP70-VP1 triggered significantly higher vaginal IgA than rVSV-VP1 and significantly higher fecal and vaginal IgA responses than rVSV-Luc-VP1, although serum IgG and T cell responses were similar. At the inoculation dose of 5.0 × 10(6) PFU, rVSV-HSP70-VP1 stimulated significantly higher T cell, fecal, and vaginal IgA responses than rVSV-VP1. Fecal and vaginal IgA responses were also significantly increased when combined vaccination of rVSV-VP1 and rVSV-HSP70 was used. Collectively, these data indicate that (i) insertion of an additional gene (HSP70 or Luc) into the rVSV-VP1 backbone further attenuates the VSV-based vaccine in vitro and in vivo, thus improving the safety of the vaccine candidate, and (ii) HSP70 enhances the human NoV-specific mucosal and T cell immunities triggered by a VSV-based human NoV vaccine.

IMPORTANCE

Human norovirus (NoV) is responsible for more than 95% of acute nonbacterial gastroenteritis worldwide. Currently, there is no vaccine for this virus. Development of a live attenuated vaccine for human NoV has not been possible because it is uncultivable. Thus, a live vector-based vaccine may provide an alternative vaccine strategy. In this study, we developed a vesicular stomatitis virus (VSV)-based human NoV vaccine candidate. We constructed rVSV-HSP70-VP1, coexpressing heat shock protein (HSP70) and capsid (VP1) genes of human NoV, and rVSV-Luc-VP1, coexpressing firefly luciferase (Luc) and VP1 genes. We found that VSVs with a double gene insertion were significantly more attenuated than VSV with a single VP1 insertion (rVSV-VP1). Furthermore, we found that coexpression or coadministration of HSP70 from VSV vector significantly enhanced human NoV-specific mucosal immunity. Collectively, we developed an improved live vectored vaccine candidate for human NoV which will be useful for future clinical studies.

Heat shock modulates neutrophil motility in zebrafish

Heat shock is a routine method used for inducible gene expression in animal models including zebrafish. Environmental temperature plays an important role in the immune system and infection progression of ectotherms. In this study, we analyzed the impact of short-term heat shock on neutrophil function using zebrafish (Danio rerio) as an animal model. Short-term heat shock decreased neutrophil recruitment to localized Streptococcus iniae infection and tail fin wounding. Heat shock also increased random neutrophil motility transiently and increased the number of circulating neutrophils. With the use of the translating ribosome affinity purification (TRAP) method for RNA isolation from specific cell types such as neutrophils, macrophages and epithelial cells, we found that heat shock induced the immediate expression of heat shock protein 70 (hsp70) and a prolonged expression of heat shock protein 27 (hsp27). Heat shock also induced cell stress as detected by the splicing of X-box binding protein 1 (xbp1) mRNA, a marker for endoplasmic reticulum (ER) stress. Exogenous expression of Hsp70, Hsp27 and spliced Xbp1 in neutrophils or epithelial cells did not reproduce the heat shock induced effects on neutrophil recruitment. The effect of heat shock on neutrophils is likely due to a combination of complex changes, including, but not limited to changes in gene expression. Our results indicate that routine heat shock can alter neutrophil function in zebrafish. The findings suggest that caution should be taken when employing a heat shock-dependent inducible system to study the innate immune response.

Bifidobacterium bifidum PRL2010 modulates the host innate immune response

Here, we describe data obtained from transcriptome profiling of human cell lines and intestinal cells of a murine model upon exposure and colonization, respectively, with Bifidobacterium bifidum PRL2010. Significant changes were detected in the transcription of genes that are known to be involved in innate immunity. Furthermore, results from enzyme-linked immunosorbent assays (ELISAs) showed that exposure to B. bifidum PRL2010 causes enhanced production of interleukin 6 (IL-6) and IL-8 cytokines, presumably through NF-κB activation. The obtained global transcription profiles strongly suggest that Bifidobacterium bifidum PRL2010 modulates the innate immune response of the host.

Recent developments in oncolytic adenovirus-based immunotherapeutic agents for use against metastatic cancers

Recurrent or metastatic cancer in most cases remains an incurable disease, and thus alternative treatment strategies, such as oncolytic virotherapy, are of great interest for clinical application. Oncolytic adenoviruses (Ads) have many advantages as virotherapeutic agents and have been safely employed in the clinics. However, the efficacy of oncolytic Ads is insufficient to eradicate tumors and current clinical applications are restricted to local administration against primary tumors because of immunological obstacles and poor tumor-cell targeting. Thus, alternative viable approaches are needed to establish therapies based on oncolytic Ad that will eliminate both primary and metastatic cancers. To this end, rational design of oncolytic Ads that express immunostimulatory genes has been employed. Even when restricted to local viral delivery, these oncolytic Ad-based immunotherapeutics have been shown to exert systemic antitumor immunity and result in eradication of both primary and metastatic cancers. Moreover, oncolytic Ad-based immunotherapeutics in combination with either dendritic cell-based vaccine or radiotherapy further strengthen the systemic tumor-specific immunity, resulting in complete suppression of both local and distant tumor metastatic growth. This review will focus on the most recent updates in strategies to develop potent oncolytic Ad-based immunotherapeutics for use in cancer gene therapy.

Feeding truncated heat shock protein 70s protect Artemia franciscana against virulent Vibrio campbellii challenge

The 70 kDa heat shock proteins (Hsp70s) are highly conserved in evolution, leading to striking similarities in structure and composition between eukaryotic Hsp70s and their homologs in prokaryotes. The eukaryotic Hsp70 like the DnaK (Escherichia coli equivalent Hsp70) protein, consist of three functionally distinct domains: an N-terminal 44-kDa ATPase portion, an 18-kDa peptide-binding domain and a C-terminal 10-kDa fragment. Previously, the amino acid sequence of eukaryotic (the brine shrimp Artemia franciscana) Hsp70 and DnaK proteins were shown to share a high degree of homology, particularly in the peptide-binding domain (59.6%, the putative innate immunity-activating portion) compared to the N-terminal ATPase (48.8%) and the C-terminal lid domains (19.4%). Next to this remarkable conservation, these proteins have been shown to generate protective immunity in Artemia against pathogenic Vibrio campbellii. This study, aimed to unravel the Vibrio-protective domain of Hsp70s in vivo, demonstrated that gnotobiotically cultured Artemia fed with recombinant C-terminal fragment (containing the conserved peptide binding domain) of Artemia Hsp70 or DnaK protein were well protected against subsequent Vibrio challenge. In addition, the prophenoloxidase (proPO) system, at both mRNA and protein activity levels, was also markedly induced by these truncated proteins, suggesting epitope(s) responsible for priming the proPO system and presumably other immune-related genes, consequently boosting Artemia survival upon challenge with V. campbellii, might be located within this conserved region of the peptide binding domain.

Mini-chaperones: potential immuno-stimulators in vaccine design

The immunogenic properties of heat shock proteins (HSPs) have prompted investigations into their application as immuno-modulatory agents. HSPs have been used as potent adjuvants in immunotherapy of cancer and infectious diseases. Some studies showed that immune activities reside within N- or C-terminal fragments of HSPs. These small fragments are sufficient to link peptides, to bind and be taken up by the receptors CD91 and scavenger receptor type A on antigen presenting cells (APCs). Thus, these mini-chaperones can be used in immunotherapy of tumors and vaccine development. The data clearly demonstrated the potential of using HSP fragments as a possible adjuvant to augment CTL response against infectious diseases. Some HSP domains have been shown to inhibit endothelial cell growth, angiogenesis or tumor growth. In this review, we describe the immuno-stimulatory activities of various mini-chaperones in development of different vaccine strategies (DNA-based vaccine and protein/peptide-based vaccines).

Immune reactivity to heat shock protein 70 expressed in the kidney is cause of salt-sensitive hypertension

Hypertension affects one-third of the adult population of the world. The causes of hypertension are incompletely understood, but relative impairment of sodium excretion is central to its pathogenesis. Immune cell infiltration in the kidney is a constant finding in hypertension that in association with local angiotensin and oxidants causes a defect in sodium excretion. However, it is unclear if the T cell influx into the kidney responds to nonspecific chemokine cues or is due to antigen-driven immune attraction. We found that T cells in experimentally induced salt-driven hypertension present a CD4 clonal response to heat shock protein 70 (HSP70) that is overexpressed in the kidney. We used a highly preserved amino acid sequence within the HSP molecule to induce immune tolerance associated with the generation of IL-10 producing regulatory T cells. Immune tolerant rats to HSP70 developed minimal renal inflammation and were protected from the development of salt-sensitive hypertension. Adoptive transfer of T lymphocytes isolated from spleen of tolerized rats also reversed hypertension. HSP70 gene delivery to the renal vein of the kidneys of rats sensitized to HSP70 caused an increment in blood pressure in response to a high-salt diet. The HSP70 peptide used in this work induces a strong proliferative response in peripheral blood lymphocytes of patients with essential hypertension. These studies provide evidence that autoimmunity plays a role in salt-sensitive hypertension and identifies HSP70 expressed in the kidney as one key antigen. These findings raise the possibility of novel approaches to the treatment of this condition.

Enhanced antitumoral efficacy and immune response following conditionally replicative adenovirus containing constitutive HSF1 delivery to rodent tumors

Background

Oncolytic adenoviruses are promising as anticancer agents but have limited clinical responses. Our previous study showed that heat shock transcription factor 1 (HSF1) overexpression could increase the anti-tumor efficacy of E1B55kD deleted oncolytic adenovirus through increasing the viral burst. Due to the important roles of heat shock proteins (HSPs) in eliciting innate and adaptive immunity, we reasoned that besides increasing the viral burst, HSF1 may also play a role in increasing tumor specific immune response.

Methods

In the present study, intra-dermal murine models of melanoma (B16) and colorectal carcinoma (CT26) were treated with E1B55kD deleted oncolytic adenovirus Adel55 or Adel55 incorporated with cHSF1, HSF1i, HSP70, or HSP90 by intra-tumoral injection. Tumors were surgically excised 72 h post injection and animals were analyzed for tumor resistance and survival rate.

Results

Approximately 95% of animals in the Adel55-cHSF1 treated group showed sustained resistance upon re-challenge with autologous tumor cells, but not in PBS, Adel55, or Adel55-HSF1i treated groups. Only 50–65% animals in the Adel55-HSP70 and Adel55-HSP90 treated group showed tumor resistance. Tumor resistance was associated with development of tumor type specific cellular immune responses. Adel55-cHSF1 treatment also showed higher efficacy in diminishing progression of the secondary tumor focus than Adel55-HSP70 or Adel55-HSP90 treatment.

Conclusions

Besides by increasing its burst in tumor cells, cHSF1 could also augment the potential of E1B55kD deleted oncolytic adenovirus by increasing the tumor-specific immune response, which is beneficial to prevent tumor recurrence. cHSF1 is a better gene for neoadjuvant immunotherapy than other heat shock protein genes.

Obtaining of three recombinant antigens of Entamoeba histolytica and evaluation of their immunogenic ability without adjuvant in a hamster model of immunoprotection

A 30-kDa surface collagen binding protein peroxiredoxin of Entamoeba histolytica (EhCBP30) was evaluated either alone or fused to the chaperone (CHP) or ATPase (ATP) domains of heat shock protein 70 of Trypanosoma cruzi (TcHSP70) as a vaccine candidate in a hamster model of experimental amoebic liver abscess (ALA) development. Three constructs were produced containing the EhCBP30 DNA sequence, one expressing EhCBP30 and two expressing EhCBP30 fused to either CHP or ATP domains of TcHSP70. High purity recombinant proteins rEhCBP30, rEhCBP30-CHP and rEhCBP30-ATP with N-terminal His tag were obtained by single step affinity purification. Hamsters were immunized without adjuvant with the antigenic recombinant proteins and then challenged intrahepatically with E. histolytica trophozoites. A 70% decrease in ALA development was detected in hamsters immunized with rEhCBP30 and rEhCBP30-CHP, while animals immunized with rEhCBP30-ATP did not show a statistically significant decrease in ALA formation compared with non-immunized animals. Histological analysis of liver tissue showed that the inflammatory infiltrate was discrete or moderate in hamsters immunized with rEhCBP30 or rEhCBP30-CHP compared with that observed in control hamsters or hamsters immunized with rEhCBP30-ATP. These results suggest that rEhCBP30 and rEhCBP30-CHP are able to induce an effective immune response that may protect hamsters against ALA development.

Pediatric Sepsis - Part V: Extracellular Heat Shock Proteins: Alarmins for the Host Immune System

Heat shock proteins (HSPs) are molecular chaperones that facilitate the proper folding and assembly of nascent polypeptides and assist in the refolding and stabilization of damaged polypeptides. Through these largely intracellular functions, the HSPs maintain homeostasis and assure cell survival. However, a growing body of literature suggests that HSPs have important effects in the extracellular environment as well. Extracellular HSPs are released from damaged or stressed cells and appear to act as local "danger signals" that activate stress response programs in surrounding cells. Importantly, extracellular HSPs have been shown to activate the host innate and adaptive immune response. With this in mind, extracellular HSPs are commonly included in a growing list of a family of proteins known as danger-associated molecular patterns (DAMPs) or alarmins, which trigger an immune response to tissue injury, such as may occur with trauma, ischemia-reperfusion injury, oxidative stress, etc. Extracellular HSPs, including Hsp72 (HSPA), Hsp27 (HSPB1), Hsp90 (HSPC), Hsp60 (HSPD), and Chaperonin/Hsp10 (HSPE) are especially attractrive candidates for DAMPs or alarmins which may be particularly relevant in the pathophysiology of the sepsis syndrome.

Identification of the heat shock protein 70 (HLHsp70) in Haemaphysalis longicornis

A Haemaphysalis longicornis heat shock protein 70 (HLHsp70) was identified from a cDNA library synthesized from tick eggs. The HLHsp70 cDNA is 2311 bp in length and encodes 661 amino acid residues with the predicted molecular weight of 72.5 kDa and an isoelectronic point (pI) of 5.2. It also contains the highly conserved functional motifs of the Hsp70 family and a specific endoplasmic reticulum (ER) retention signal "KDEL" that is common among ER-localized proteins. The HLHsp70 exhibits 90% amino acid identity to the putative Hsp70 of Ixodes scapularis, and 85% to Gallus gallus 78 kDa glucose-regulated protein precursor. Real time RT-PCR analysis showed that the expression levels of the Hsp70 in ovaries and salivary glands were significantly higher than in other tested tissues in partially fed females. Although the expression level of the HLHsp70 was constantly low in unfed ticks, it was significantly induced by blood-feeding. Further, the expression was positively correlated to the temperature (4-37°C, tested). Western blot analysis showed that the rabbit antiserum against the recombinant HLHsp70 protein (rHLHSP70) recognized bands of approximately 100, 72, and 28 kDa from egg lysates, as well as a 72kDa fragment in protein extracts from partially fed larvae. Immunization of rabbits with the rHLHSP70 did not result in a statistically significant reduction of female tick engorgement and oviposition. These results suggest that although HLHSP70 plays a role in the physiological activities of ticks, as a constitutive protein it was not suitable for selection as a candidate vaccine antigen against ticks.

Lymphoid neoplastic P388D1 cells express membrane protein candidates that discriminate among the C-terminal phylogenetic diversity in heat shock protein 70 sequences

We previously found that mouse inducible Hsp72 bound more extensively to lymphoblast-like lymphoid neoplastic P388D1 cells than to RAW264.7 monocyte-macrophages. In the present study, we analyzed the characteristics of the binding to P388D1 cells of recombinant HSP70 derived from different species. Recombinant mouse inducible-type Hsp72 bound extensively to P388D1 cells in a saturable manner, but not to P815 mastocytoma or EL4 thymoma. Spinach Hsc70-1, highly homologous with mouse Hsp72 in the C-terminal region, also bound to P388D1 cells. In contrast, significant binding was not observed for bacterial DnaK derived from Lactobacillus acidophilus and Escherichia coli which have relatively little homology in this region. Analyses of surface antigens showed that B220, and CD19, but not CD91, LOX-1, and CD40, the HSP70 receptors reported so far, were present on P388D1 cells, suggesting a B-cell lineage for this cell line. A similar discrimination of the diversity between mouse Hsp72 and bacterial DnaK occurred for CD19(+) B cells derived from mouse spleen, Peyer's patches, and mesenteric lymph nodes. The binding of HSP70 to P388D1 cells was partially, but significantly, antagonized by fucoidan and maleylated BSA, implying a few types of scavenger receptors to be responsible for the binding of HSP70 to this cell line. Furthermore, photo-affinity labeling revealed several membrane protein candidates larger than 110kDa to be involved in the recognition of HSP70 molecules. Using a NF-κB-luciferase reporter assay, we found that exogenous HSP70 did not stimulate NF-κB-dependent signal transduction in P388D1 cells. It thus follows that lymphoid neoplastic P388D1 cells express membrane protein candidates that discriminate among the C-terminal sequences of the HSP70 family. The present results indicate that several types of cells in the innate immune system may distinguish among the phylogenetically specific signals in protein molecules.

Extremely low-frequency electromagnetic fields affect the immune response of monocyte-derived macrophages to pathogens

This study aimed to determine the effect of extremely low-frequency electromagnetic fields (ELF-EMF) on the physiological response of phagocytes to an infectious agent. THP-1 cells (human monocytic leukemia cell line) were cultured and 50 Hz, 1 mT EMF was applied for 4-6 h to cells induced with Staphylococcus aureus or interferon gamma/lipopolysaccharide (IFγ/LPS). Alterations in nitric oxide (NO), inducible nitric oxide synthase (iNOS) levels, heat shock protein 70 levels (hsp70), cGMP levels, caspase-9 activation, and the growth rate of S. aureus were determined. The growth curve of exposed bacteria was lower than the control. Field application increased NO levels. The increase was more prominent for S. aureus-induced cells and appeared earlier than the increase in cells without field application. However, a slight decrease was observed in iNOS levels. Increased cGMP levels in response to field application were closely correlated with increased NO levels. ELF-EMF alone caused increased hsp70 levels in a time-dependent manner. When cells were induced with S. aureus or IFγ/LPS, field application produced higher levels of hsp70. ELF-EMF suppressed caspase-9 activation by a small extent. These data confirm that ELF-EMF affects bacterial growth and the response of the immune system to bacterial challenges, suggesting that ELF-EMF could be exploited for beneficial uses.

Molecular chaperones and protein-folding catalysts as intercellular signaling regulators in immunity and inflammation

This review critically examines the hypothesis that molecular chaperones and protein-folding catalysts from prokaryotes and eukaryotes can be secreted by cells and function as intercellular signals, principally but not exclusively, for leukocytes. A growing number of molecular chaperones have been reported to function as ligands for selected receptors and/or receptors for specific ligands. Molecular chaperones initially appeared to act primarily as stimulatory signals for leukocytes and thus, were seen as proinflammatory mediators. However, evidence is now emerging that molecular chaperones can have anti-inflammatory actions or, depending on the protein and concentration, anti- and proinflammatory functions. Recasting the original hypothesis, we propose that molecular chaperones and protein-folding catalysts are "moonlighting" proteins that function as homeostatic immune regulators but may also under certain circumstances, contribute to tissue pathology. One of the key issues in the field of molecular chaperone biology relates to the role of microbial contaminants in their signaling activity; this too will be evaluated critically. The most fascinating aspect of molecular chaperones probably relates to evidence for their therapeutic potential in human disease, and ongoing studies are evaluating this potential in a range of clinical settings.

Long-term protection against human papillomavirus e7-positive tumor by a single vaccination of adeno-associated virus vectors encoding a fusion protein of inactivated e7 of human papillomavirus 16/18 and heat shock protein 70

We investigated a gene vaccine strategy against human papillomavirus (HPV)-induced cancer and premalignant diseases, using adeno-associated virus (AAV) vector encoding the viral E7 oncoproteins as the tumor antigens from HPV serotypes 16 (HPV16) and 18 (HPV18). Genetically inactivated E7 proteins were fused with a heat shock protein 70 (hsp70) to minimize the risk of cell transformation and enhance immune responses. The fusion protein gene was packaged in AAV serotype 1 or 2 (AAV1 or 2) for efficient in vivo gene expression. Our results showed that after a single intramuscular injection, the AAV1 vector elicited stronger HPV-specific cytotoxic T lymphocyte (CTL) responses and interferon-gamma secretion when compared with the AAV2 vector. Prophylactic immunization with AAV1 protected 100% of the mice from tumor growth for more than 1 year, whereas all the control mice immunized with either a LacZ vector or saline grew large tumors and died within 6 weeks after inoculation of E7-positive tumor cell line TC-1. In addition, this single-dose AAV1 vaccination completely protected the mice against second and third challenges with higher numbers of TC-1 cells. Despite lower CTL responses against the E7 antigens, AAV2 vector prophylactic immunization was also sufficient to protect 100% of the mice against the initial and second tumor challenges and 70% of the mice against the third challenge. In addition, therapeutic immunization with AAV1 after palpable tumor formation inhibited tumor growth and caused tumor regression in some mice. Thus, our studies support the potential of AAV vectors as a genetic vaccine for the prevention and treatment of HPV-induced malignancies.

MHC independent anti-tumor immune responses induced by Hsp70-enriched exosomes generate tumor regression in murine models

The ideal cancer vaccine should work regardless of MHC types but currently the barrier generated by MHC specificity hampers the development of human cancer vaccines, requesting to identify strong immunogenic molecules that can induce anti-cancer immune responses without being affected by MHC polymorphism. Tumor-derived exosomes are small membrane vesicles containing tumor antigens as well as other immunologically important molecules such as MHC molecules and heat shock proteins (HSPs). Because of their potential immunogenicity, the plausible utility of tumor-derived exosomes as an MHC independent cancer vaccine was proposed. Here, we investigated whether Hsp70-enriched tumor exosomes can induce stronger immunogenicity as compared to normal tumor-derived exosomes in autologous as well as allogeneic murine models in vitro and in vivo. Western blotting showed that the exosomes of heat-treated tumor cells (HS Exo) contained higher amounts of Hsp70 than the exosomes of untreated cells (CNTL Exo). In both MHC type-identical and -irrelevant antigen-presenting cell models in vitro, HS Exo triggered the increased expressions of MHC class II molecules. Crucially, HS Exo performed greater therapeutic capability in regressing pre-established MHC type-identical and -irrelevant tumors than CNTL Exo in vivo. The analyses of anti-tumor function in allogeneic mouse model demonstrated that HS Exo elicited Th1-polarized immune responses defined by the increased productions of IgG2a and IFN-gamma. In summary, the Hsp70-enriched exosomes extracted from heat-treated tumors induced strong Th1 immune responses, resulting in eliminating cancer cells in allogeneic hosts in vivo. These results indicate that HS Exo is a potent MHC independent cell-free cancer therapeutic agent that can be developed for clinical trials.

Amniotic fluid heat shock protein 70 concentration in histologic chorioamnionitis, term and preterm parturition

OBJECTIVE

Heat shock protein (HSP) 70, a conserved member of the stress protein family, is produced in almost all cell types in response to a wide range of stressful stimuli, and its production has a survival value. Evidence suggests that extracellular HSP70 is involved in the activation of the innate and adaptive immune response. Furthermore, increased mRNA expression of HSP70 has been observed in human fetal membranes following endotoxin stimulation. This study was conducted to determine the changes in amniotic fluid HSP70 concentrations during pregnancy, term and preterm parturition, intra-amniotic infection (IAI), and histologic chorioamnionitis.

STUDY DESIGN

A cross-sectional study was conducted in 376 pregnant women in the following groups: (1) women with a normal pregnancy who were classified into the following categories: (a) women in the mid-trimester (14-18 weeks) who underwent amniocentesis for genetic indications and delivered normal infants at term (n=72); (b) women at term not in labor (n = 23); and (c) those at term in labor (n = 48). (2) Women with spontaneous preterm labor and intact membranes who were subdivided into the following categories: (a) preterm labor who delivered at term without IAI (n = 42); (b) preterm labor who delivered preterm without IAI (n = 57); and (c) preterm labor and delivery with IAI (n = 30). (3) Women with preterm prelabor rupture of membranes (PROM) with (n = 50) and without (n = 54) IAI. Among patients with preterm labor with intact membranes and preterm PROM who delivered within 72 hours of amniocentesis, placenta, umbilical cord, and chorioamniotic membranes were collected and assessed for the presence or absence of acute inflammatory lesions in the extraplacental membranes (histologic chorioamnionitis) and/or umbilical cords (funisitis). HSP70 concentrations in amniotic fluid were determined using a sensitive and specific immunoassay. Non-parametric statistics were used for analysis. A p value of <0.05 was considered statistically significant.

RESULTS

Immunoreactive HSP70 was detected in 88% (332/376) of amniotic fluid samples. The median amniotic fluid HSP70 concentration was significantly higher in women at term without labor than in those in the mid-trimester (term no labor: median 34.9 ng/mL, range 0-78.1 ng/mL vs. mid-trimester; median 6.6 ng/mL, range 0-20.8 ng/mL; p<0.001). Among patients with spontaneous preterm labor and preterm PROM, those with IAI had a significantly higher median amniotic fluid HSP70 concentration than those without IAI (preterm labor with IAI: median 82.9 ng/mL, range 0-500 ng/mL vs. preterm labor without IAI: median 41.7 ng/mL, range 0-244 ng/mL; p = 0.001; preterm PROM with IAI: median 86.5 ng/mL, range 0-428 ng/mL vs. preterm PROM without IAI: median 55.9 ng/mL, range 14.9-299.9 ng/mL; p = 0.007). There was no significant difference in the median amniotic fluid HSP70 concentration between patients with preterm labor who delivered preterm without IAI and those who delivered at term (p = 0.6). However, among patients with preterm labor without IAI, there was an inverse relationship between amniotic fluid concentration of HSP70 and the amniocentesis-to-spontaneous delivery interval (Spearman's Rho = -0.26; p = 0.02). Patients with histologic chorioamnionitis/funisitis had a significantly higher median amniotic fluid HSP70 concentration than those without inflammation (inflammation: median 108.7 ng/mL, range 0-500 ng/mL vs. without inflammation: median 67.9 ng/mL, range 7.1-299.9 ng/mL; p = 0.02). Women at term in labor had a median amniotic fluid concentration of HSP70 significantly higher than those not in labor (term in labor: median 60.7 ng/mL, range 0-359.9 ng/mL vs. term not in labor: median 34.9 ng/mL, range 0-78.1 ng/mL; p = 0.02).

CONCLUSIONS

Intra-amniotic infection, histologic chorioamnionitis, and term parturition are associated with elevated amniotic fluid HSP70 concentrations. HSP70 plays a role in the host defense mechanism by activating the innate arm of the immune response in women with intrauterine infection. The mechanisms of preterm and term parturition in humans may involve extracellular HSP70.

The therapeutic implications of clinically applied modifiers of heat shock protein 70 (Hsp70) expression by tumor cells

Evidence that membrane-bound and extracellular heat shock proteins (HSPs) with molecular weights of 70 and 90 kDa are potent stimulators of the immune responses has accumulated over the last decade. In this review, we discuss the modulation of Hsp70 expression, a major stress-inducible member of the HSP70 family, in the cytoplasm and on the plasma membrane of tumor cells by clinically applied interventions such as radio- and chemotherapy.

MAPK pathway mediates EGR-1-HSP70-dependent cigarette smoke-induced chemokine production

Cigarette smoking, a major risk factor for chronic obstructive pulmonary disease, can cause airway inflammation, airway narrowing, and loss of elasticity, leading to chronic airflow limitation. In this report, we sought to define the signaling pathways activated by smoke and to identify molecules responsible for cigarette smoke-induced inflammation. We applied cigarette smoke water extract (CSE) to primary human lung fibroblasts and found that CSE significantly increased CXC chemokine IL-8 production. Meanwhile, 70-kDa heat shock protein (HSP70) was also induced by CSE in a dose- and time-dependent manner. CSE treatment stimulated HSP70 secretion by primary fibroblasts, which augmented IL-8 production. This was further confirmed by exogenously added recombinant HSP70. Using HSP70 small interfering RNA, we confirmed that CSE-induced chemokine production was dependent on heat shock protein expression. Further investigation showed that CSE could also stimulate early growth response-1 (EGR-1) in an ERK-dependent manner and that the expression of HSP70 was EGR-1 dependent. In view of these findings, we hypothesize that the MAPK-EGR-1-HSP70 pathway regulates the cigarette smoke-induced inflammatory process.

Host antitumour immune responses to HIFU ablation

The ideal cancer therapy not only induces the death of all localized tumour cells without damage to surrounding normal tissue, but also activates a systemic antitumour immunity. High-intensity focused ultrasound (HIFU) has the potential to be such a treatment, as it can non-invasively ablate a targeted tumour below the skin surface, and may subsequently augment host antitumour immunity. In addition to thermal and cavitation effects, which act directly and locally on the tumour, there is increasing evidence linking systemic anti-tumour immune response to HIFU ablation. This may provide micro-metastatic control and long-term tumour resistance for cancer patients. The goal of this article is to review the emerging pre-clinical and clinical results suggesting that HIFU ablation may enhance host anti-tumour immunity, and to discuss its potential mechanisms. It is concluded that the systemic immune response induced by thermal ablation may play an important role in local recurrence and metastasis control after HIFU treatment.

Functional region of mouse heat shock protein 72 for its binding to lymphoid neoplastic P388D1 cells

Extracellular heat shock proteins have been reported to participate in both innate and adaptive immune responses. We have found that recombinant mouse inducible heat shock protein 72 (Hsp72) bound to lymphoid neoplastic P388D1 cells. In the present study, we examined which region of mouse Hsp72 interacted with this cell line by using truncated variants that are sequentially lacking sections of the C-terminal region. The full-length mouse Hsp72 specifically bound to P388D1 cells, but not to mastocytoma P815 cells. Deletion of the C-terminal tail portion of mouse Hsp72 markedly decreased the binding to P388D1 cells and the sequential truncation of the C-terminal helical region led to a loss of binding activity. Specific binding was not observed for either the variant with a minimal substrate-binding structure or the ATP-binding domain alone. On the other hand, two truncated variants lacking the ATP-binding domain significantly bound to P388D1 cells. However, the variant lacking the substrate-binding domain did not show any binding to this cell line. These results suggest that the activity to bind P388D1 cells is attributable to the C-terminal region of mouse Hsp72 in combination with the substrate-binding domain. Interestingly, the binding of mouse Hsp72 to P388D1 cells was competed by the variant with the C-terminal flexible tail sequence, but not by the variant without that sequence. These competitive experiments imply that there may be at least two membrane receptors on P388D1 cells and also that both receptors may recognize the various structures in the C-terminal region of the Hsp70 family for regulation of innate immunity.

Expression of tumor antigens and heat-shock protein 70 in breast cancer cells after high-intensity focused ultrasound ablation

BACKGROUND

Previous results have shown that high-intensity focused ultrasound (HIFU) ablation can potentially activate a host antitumor immunity. The goal of this study was to investigate whether the tumor antigens expressed on breast cancer cells may be preserved after HIFU treatment, and to explore the potential mechanisms regarding the enhanced antitumor response.

METHODS

The primary lesion in 23 patients with biopsy-proven breast cancer were treated with HIFU, then submitted to modified radical mastectomy. By using biotin-streptavidin-peroxidase immunohistochemical technology, a variety of cellular molecules expressed on breast cancer cells, including tumor antigens and heat-shock protein 70 (HSP-70), were stained in all breast specimens. A complete absence of staining was recorded as negative, and immunoreaction of the tumor cells was considered to be positive for antigen expression.

RESULTS

Nuclear positivity of breast cancer cells for proliferating cell nuclear antigen, estrogen receptor, and progesterone receptor was detected in 0%, 9%, and 9% of the treated samples, respectively. The positive rate of cytoplasmic staining for matrix metalloproteinase 9, carbohydrate antigen 15-3, vascular endothelial growth factor, transforming growth factors beta1 and beta2, interleukin 6, and interleukin 10 was 0%, 52%, 30%, 57%, 70%, 48%, and 61% in the treated cancer cells, respectively. The positive rate of cellular membrane staining for epithelial membrane antigen, CD44v6, and HSP-70 was 100%, 0%, and 100% in the zones of treated cancer cells, respectively.

CONCLUSIONS

After HIFU ablation, some tumor antigens remained in the tumor debris. This could provide a potential antigen source to stimulate antitumor immune response.

Exogenous heat shock protein 70 mediates sepsis manifestations and decreases the mortality rate in rats

Mammalian responses to bacterial lipopolysaccharide (LPS) from the outer membrane of Gram-negative bacteria can lead to an uncontrolled inflammatory reaction that can be deadly for the host. We checked whether heat shock protein 70 (Hsp70) protein is able to protect animals from the deleterious effects of bacterial LPS by monitoring the effect of exogenous Hsp70 injections before and after LPS administration. Our research with rats demonstrates for the first time that administration of exogeneous Hsp70 before and after LPS challenges can reduce mortality rates and modify several parameters of hemostasis and hemodynamics. Hsp70 isolated from bovine muscles showed significant protective effects against the impaired coagulation and fibrinolytic systems caused by LPS, and reduced the mortality caused by Escherichia coli and Salmonella typhimurium LPS injections significantly. Characteristically, Hsp70 preparations used in the experiments result in different effects when administered before and after an LPS challenge, and the effects of Hsp70 injections also differ significantly depending on the origin of the LPS (E coli vs S typhimurium). Based on our data, mammalian Hsp70 appears to be an attractive target in therapeutic strategies designed to stimulate endogenous protective mechanisms against many deleterious consequences of septic shock by accelerating the functional recovery of susceptible organs in humans.

On the brotherhood of the mitochondrial chaperones mortalin and heat shock protein 60

The heat shock chaperones mortalin/mitochondrial heat shock protein 70 (mtHsp70) and Hsp60 are found in multiple subcellular sites and function in the folding and intracellular trafficking of many proteins. The chaperoning activity of these 2 proteins involves different structural and functional mechanisms. In spite of providing an excellent model for an evolutionarily conserved molecular "brotherhood", their individual functions, although overlapping, are nonredundant. As they travel to various locations, both chaperones acquire different binding partners and exert a more divergent involvement in tumorigenesis, cellular senescence, and immunology. An understanding of their functional biology may lead to novel designing and development of therapeutic strategies for cancer and aging.

15-Deoxyspergualin modulates Plasmodium falciparum heat shock protein function

Heat shock proteins are essential for the survival of all cells. The C-terminal EEVD motif of Hsp70 has previously been implicated in binding 15-deoxyspergualin (DSG), an immunosuppressant with antimalarial activity whose mechanism of action is uncertain. We report the cloning, overexpression, and characterization of three members of the heat shock family, PfHsp70-1 (an Hsp70 protein with a C-terminal EEVD motif), PfHsp70-2 (an Hsp70 protein without the EEVD motif), and PfHsp70 interacting protein. The chaperone activity of PfHsp70-1, and PfHsp70-2 was enhanced by ATP and by PfHip. Interestingly, while binding of protein substrates to PfHsp70-1, PfHsp70-2 and PfHip was unaffected in the presence of DSG, the ATP enhanced chaperone activity of PfHsp70-1 but not PfHsp70-2 was stimulated further by DSG. Our finding suggests that the binding partner of DSG in the parasite cellular milieu is PfHsp70-1 and paves the way for the elucidation of the mechanism of antimalarial action of DSG.

Immunoadjuvant chaperone, GRP170, induces 'danger signals' upon interaction with dendritic cells

When chaperoning tumour antigens, glucose-regulated protein 170 (GRP170) is capable of inducing effective antitumour immune responses. In the present study, we determined whether such immunoadjuvant properties of GRP170 also involve the ability to induce 'danger signals' through interaction with APC. We prepared recombinant GRP170 in the baculovirus expression system with low endotoxin concentration at which LPS did not have any effect on dendritic cells (DC). We showed that GRP170 binds DC in a receptor-mediated fashion and induces DC to upregulate the expression of MHC class II, CD86 and CD40 molecules, and to secrete pro-inflammatory cytokines. GRP170 also induced expression of CD40 molecules in a B16F10 cell line, whereas LPS failed to do so. These findings show that GRP170 acts as a danger signal through its interaction with DC, regardless of its endotoxin component.

Therapeutic aspects of chaperones/heat-shock proteins in neuro-oncology

Tumors of the CNS frequently have devastating consequences in terms of cognitive and motor function, personality and mortality. Despite decades of work, current therapies have done little to alter the course of these deadly diseases. The discovery that chaperones/heat-shock proteins play an important role in tumor biology and immunology have sparked much interest in utilizing these proteins as targets of therapeutics, or as therapeutics themselves, in the treatments of a variety of cancers. Neuro-oncology has only recently taken notice of these entities, and the purpose of this review is to provide a background, an update and a view to the future for the roles of chaperones/heat-shock proteins in the treatment of brain tumors.

Fusion protein of ATPase domain of Hsc70 with TRP2 acting as a tumor vaccine against B16 melanoma

HSP70s are a family of ATP-dependent chaperones of relative molecular masses around 70kDa. Immunization of mice with HSP70 isolated from tumor tissues has been proved to elicit specific protective immunity against the original tumor. Recent researches have demonstrated that the ATPase domain of HSP70 and the tumor antigenic peptide that binds to Hsp70 were the crucial parts eliciting tumor-specific immunity. These findings suggested that a recombinant protein expressed in Escherichia coli, comprising a covalently fused fragment of tumor rejection antigen to ATPase domain of HSP70, could be used as a tumor vaccine. However, high-level expressions of heterologous recombinant proteins in E. coli often lead to the formation of inclusion bodies, resulting in defects in solubility and bioactivity. In the present work, we found an approach to resolve these problems, focusing on a refolding procedure via gel-filtration chromatography for denatured inclusion body proteins. Here, we expressed, purified and refolded a fusion protein comprising murine heat shock cognate protein 70 (Hsc70) N-terminal ATPase domain (Hsc70NTD) and a portion of TRP2 (aa153-417) as a model protein. The refolding effectivities were assessed according to their ATPase activities, the vaccine function was assessed according to immunization effect in inducing antigen-specific CTLs and to in vivo tumor protection. The results showed that the fusion protein refolded via gel-filtration chromatography exhibited ATPase activity, succeeded in eliciting antigen-specific CTL in vivo and delayed tumor growth on tumor-bearing mice.

Heat shock proteins in cancer: diagnostic, prognostic, predictive, and treatment implications

Heat shock proteins (Hsps) are overexpressed in a wide range of human cancers and are implicated in tumor cell proliferation, differentiation, invasion, metastasis, death, and recognition by the immune system. We review the current status of the role of Hsp expression in cancer with special emphasis on the clinical setting. Although Hsp levels are not informative at the diagnostic level, they are useful biomarkers for carcinogenesis in some tissues and signal the degree of differentiation and the aggressiveness of some cancers. In addition, the circulating levels of Hsp and anti-Hsp antibodies in cancer patients may be useful in tumor diagnosis. Furthermore, several Hsp are implicated with the prognosis of specific cancers, most notably Hsp27, whose expression is associated with poor prognosis in gastric, liver, and prostate carcinoma, and osteosarcomas, and Hsp70, which is correlated with poor prognosis in breast, endometrial, uterine cervical, and bladder carcinomas. Increased Hsp expression may also predict the response to some anticancer treatments. For example, Hsp27 and Hsp70 are implicated in resistance to chemotherapy in breast cancer, Hsp27 predicts a poor response to chemotherapy in leukemia patients, whereas Hsp70 expression predicts a better response to chemotherapy in osteosarcomas. Implication of Hsp in tumor progression and response to therapy has led to its successful targeting in therapy by 2 main strategies, including: (1) pharmacological modification of Hsp expression or molecular chaperone activity and (2) use of Hsps in anticancer vaccines, exploiting their ability to act as immunological adjuvants. In conclusion, the present times are of importance for the field of Hsps in cancer, with great contributions to both basic and clinical cancer research.