Induction of the human heat shock promoter HSP70B by nutritional stress: implications for cancer gene therapy

A Review of the Use of Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Malignancy in Pediatric Patients

Hyperthermic intraperitoneal chemotherapy (HIPEC) can directly target microscopic peritoneal disease, has achieved regular consideration in the treatment of several adult cancer types, and is more recently being studied in pediatrics. This review paper provides an overview of the use of this modality in pediatrics in order to identify medication choice, discuss post-operative morbidity and mortality, and evaluate impact on overall survival. Four databases were searched including Scopus, PubMed, Embase, and CINAHL and ultimately 37 papers documenting the use of this modality comprising 264 pediatric patients were included. Malignancies treated include desmoplastic small round cell tumor, rhabdomyosarcoma, angiosarcoma, colorectal carcinoma, and mesothelioma, with several rarer tumor types. Cisplatin was the most commonly used drug for HIPEC at varying concentrations for 30-90 min in duration at temperatures of approximately 41-42 °C. Reported toxicities were generally self-limited and there was no post-operative mortality. The impact on overall survival versus systemic chemotherapy and debulking surgery is uncertain due to lack of clinical trials and very small sample size across tumor subsets and the overall pediatric population. The relationship between degree of tumor burden and extent of surgical debulking needs to be further clarified. Future directions include prospective clinical trials, establishment of patient databases to facilitate standardization of HIPEC in pediatric patients, and additional approaches to optimize HIPEC.

Effective control of tumor growth through spatial and temporal control of theranostic sodium iodide symporter (NIS) gene expression using a heat-inducible gene promoter in engineered mesenchymal stem cells

Purpose: The tumor homing characteristics of mesenchymal stem cells (MSCs) make them attractive vehicles for the tumor-specific delivery of therapeutic agents, such as the sodium iodide symporter (NIS). NIS is a theranostic protein that allows non-invasive monitoring of the in vivo biodistribution of functional NIS expression by radioiodine imaging as well as the therapeutic application of ¹³¹I. To gain local and temporal control of transgene expression, and thereby improve tumor selectivity, we engineered MSCs to express the NIS gene under control of a heat-inducible HSP70B promoter (HSP70B-NIS-MSCs).

Experimental Design: NIS induction in heat-treated HSP70B-NIS-MSCs was verified by ¹²⁵I uptake assay, RT-PCR, Western blot and immunofluorescence staining. HSP70B-NIS-MSCs were then injected i.v. into mice carrying subcutaneous hepatocellular carcinoma HuH7 xenografts, and hyperthermia (1 h at 41°C) was locally applied to the tumor. 0 - 72 h later radioiodine uptake was assessed by ¹²³I-scintigraphy. The most effective uptake regime was then selected for ¹³¹I therapy.

Results: The HSP70B promoter showed low basal activity in vitro and was significantly induced in response to heat. In vivo, the highest tumoral iodine accumulation was seen 12 h after application of hyperthermia. HSP70B-NIS-MSC-mediated ¹³¹I therapy combined with hyperthermia resulted in a significantly reduced tumor growth with prolonged survival as compared to control groups.

Conclusions: The heat-inducible HSP70B promoter allows hyperthermia-induced spatial and temporal control of MSC-mediated theranostic NIS gene radiotherapy with efficient tumor-selective and temperature-dependent accumulation of radioiodine in heat-treated tumors.

The human HSP70 family of chaperones: where do we stand?

The 70-kDa heat shock protein (HSP70) family of molecular chaperones represents one of the most ubiquitous classes of chaperones and is highly conserved in all organisms. Members of the HSP70 family control all aspects of cellular proteostasis such as nascent protein chain folding, protein import into organelles, recovering of proteins from aggregation, and assembly of multi-protein complexes. These chaperones augment organismal survival and longevity in the face of proteotoxic stress by enhancing cell viability and facilitating protein damage repair. Extracellular HSP70s have a number of cytoprotective and immunomodulatory functions, the latter either in the context of facilitating the cross-presentation of immunogenic peptides via major histocompatibility complex (MHC) antigens or in the context of acting as "chaperokines" or stimulators of innate immune responses. Studies have linked the expression of HSP70s to several types of carcinoma, with Hsp70 expression being associated with therapeutic resistance, metastasis, and poor clinical outcome. In malignantly transformed cells, HSP70s protect cells from the proteotoxic stress associated with abnormally rapid proliferation, suppress cellular senescence, and confer resistance to stress-induced apoptosis including protection against cytostatic drugs and radiation therapy. All of the cellular activities of HSP70s depend on their adenosine-5'-triphosphate (ATP)-regulated ability to interact with exposed hydrophobic surfaces of proteins. ATP hydrolysis and adenosine diphosphate (ADP)/ATP exchange are key events for substrate binding and Hsp70 release during folding of nascent polypeptides. Several proteins that bind to distinct subdomains of Hsp70 and consequently modulate the activity of the chaperone have been identified as HSP70 co-chaperones. This review focuses on the regulation, function, and relevance of the molecular Hsp70 chaperone machinery to disease and its potential as a therapeutic target.

Involvement of heat shock proteins in gluten-sensitive enteropathy

Gluten-sensitive enteropathy, also known as coeliac disease (CD), is an autoimmune disorder occurring in genetically susceptible individuals that damages the small intestine and interferes with the absorption of other nutrients. As it is triggered by dietary gluten and related prolamins present in wheat, rye and barley, the accepted treatment for CD is a strict gluten-free diet. However, a complete exclusion of gluten-containing cereals from the diet is often difficult, and new therapeutic strategies are urgently needed. A class of proteins that have already emerged as drug targets for other autoimmune diseases are the heat shock proteins (HSPs), which are highly conserved stress-induced chaperones that protect cells against harmful extracellular factors. HSPs are expressed in several tissues, including the gastrointestinal tract, and their levels are significantly increased under stress circumstances. HSPs exert immunomodulatory effects, and also play a crucial role in the maintenance of epithelial cell structure and function, as they are responsible for adequate protein folding, influence the degradation of proteins and cell repair processes after damage, and modulate cell signalling, cell proliferation and apoptosis. The present review discusses the involvement of HSPs in the pathophysiology of CD. Furthermore, HSPs may represent a useful therapeutic target for the treatment of CD due to the cytoprotective, immunomodulatory, and anti-apoptotic effects in the intestinal mucosal barrier.

Use of in vivo bioluminescence and MRI to determine hyperthermia-induced changes in luciferase activity under the control of an hsp70 promoter

We investigated the in vivo effect of hyperthermia on the expression of heat shock proteins and MRI changes in three tumor cell lines. Three tumor cell lines (SCCVII, NIH3T3, M21) were transfected with a plasmid containing the heat shock protein 70 gene (hsp70) promoter fragment and the luciferase reporter gene, and injected into mice. Tumors of 1100 mm³ in size were exposed to five different temperatures (38, 40, 42, 44 and 46 °C) in a water bath. Bioluminescence and MRI were performed at set time intervals. The MRI scan protocol was as follows: T₁-weighted spin echo ± contrast medium, T₂-weighted fast spin echo, dynamic contrast-enhanced MRI, diffusion-weighted stimulated echo acquisition mode sequence, T₂ time obtained on a 1.5T General Electric MRI scanner. Immunoblotting was also performed. hsp70 transcription was strongly induced at 42 and 44 °C, reaching values as high as 8531.5 ± 432.1-fold above baseline in NIH3T3 tumors. At these temperatures, significant increases in the uptake of contrast medium, slope of initial enhancement, Ak(ep) values and apparent diffusion coefficient (ADC) were observed in the 8-h scan of the NIH3T3 cell line. In SCCVII tumors, ADC increased by about 23% (p = 0.010) in the scans performed at 8, 24, 48 and 96 h. At 46 °C, luciferase activity was reduced significantly in the three cell lines. In all tumor types, a significant increase in ADC was observed, which was highest in SCCVII tumors (33.8%; p < 0.01). In accordance with the bioluminescence results, significant Hsp70 protein production was shown by immunoblot analysis. The best correlation coefficient between luciferase activity and immunoblotting results was found for M21 tumors (r = 0.93, p < 0.0001). Different tissue types display distinct patterns of hsp70 transcription. MRI can be used, in combination with optical imaging, to provide information on hsp70 transcription and protein production. The major finding of the present study was that heat-related biochemical changes in tumor tissue can be determined by MRI.

Na-glutamine co-transporters B(0)AT1 in villus and SN2 in crypts are differentially altered in chronically inflamed rabbit intestine

Glutamine is a major nutrient utilized by the intestinal epithelium and is primarily assimilated via Na-glutamine co-transport (NGcT) on the brush border membrane (BBM) of enterocytes. Recently we reported that B(0)AT1 (SLC6A19) mediates glutamine absorption in villus while SN2 (SLC38A5) does the same in crypt cells. However, how B(0)AT1 and SN2 are affected during intestinal inflammation is unknown. In the present study it was shown that during chronic enteritis NGcT was inhibited in villus cells, however, it was stimulated in crypt cells. Our studies also demonstrated that the mechanism of inhibition of NGcT during chronic enteritis was secondary to a reduction in the number of B(0)AT1 co-transporters in the villus cell BBM without a change in the affinity of the co-transporter. In contrast, stimulation of NGcT in crypt cells was secondary to an increase in the affinity of SN2 for glutamine without an alteration in the number of co-transporters. Thus, glutamine assimilation which occurs via distinct transporters in crypt and villus cells is altered in the chronically inflamed intestine.

Current devices for high-performance whole-body hyperthermia therapy

For late-stage cancer, whole-body hyperthermia (WBH) is highly regarded by physicians as a promising alternative to conventional therapies. Although WBH is still under scrutiny due to potential toxicity, its benefits are incomparable, as diversified devices and very promising treatment protocols in this area are advanced into Phase II and III clinical trials. Following the introduction of the WBH principle, this paper comprehensively reviews the state-of-art high-performance WBH devices based on the heat induction mechanisms - radiation, convection and conduction. Through analyzing each category's physical principle and heat-induction property, the advantages and disadvantages of the devices are evaluated. Technical strategies and critical scientific issues are summarized. For future developments, research directions worth pursuing are presented in this article.

Heat-responsive gene expression for gene therapy

Therapy-inducible vectors are useful for conditional expression of therapeutic genes in gene therapy, which is based on the control of gene expression by conventional treatment modalities. By this approach, combination of chemotherapy, radiation or hyperthermia with gene therapy can result in considerable, additive or synergistic improvement of therapeutic efficacy. This concept has been successfully tested in particular for gene therapy of cancer. The identification of efficient heat-responsive gene promoters provided the rationale for heat-regulated gene therapy. The objective of this review is to provide insights into the cellular mechanisms of heat-shock response, as prerequisite for therapeutic actions of hyperthermia and into the field of heat-responsive gene therapy. Furthermore, the major strategies of heat-responsive gene therapy systems in particular for cancer treatment are summarized. The developments for heat-responsive vector systems for in vitro and in vivo approaches are discussed. This review will provide an overview for this gene therapy strategy and its potential for multimodal therapeutic concepts in the clinic.