Proliferating cell nuclear antigen and heat shock protein 70 immunolocalization in invasive ductal breast cancer not otherwise specified

Capsaicin binds the N-terminus of Hsp90, induces lysosomal degradation of Hsp70, and enhances the anti-tumor effects of 17-AAG (Tanespimycin)

Heat shock protein 90 (Hsp90) and its co-chaperones promote cancer, and targeting Hsp90 holds promise for cancer treatment. Most of the efforts to harness this potential have focused on targeting the Hsp90 N-terminus ATP binding site. Although newer-generation inhibitors have shown improved efficacy in aggressive cancers, induction of the cellular heat shock response (HSR) by these inhibitors is thought to limit their clinical efficacy. Therefore, Hsp90 inhibitors with novel mechanisms of action and that do not trigger the HSR would be advantageous. Here, we investigated the mechanism by which capsaicin inhibits Hsp90. Through mutagenesis, chemical modifications, and proteomic studies, we show that capsaicin binds to the N-terminus of Hsp90 and inhibits its ATPase activity. Consequently, capsaicin and its analogs inhibit Hsp90 ATPase-dependent progesterone receptor reconstitution in vitro. Capsaicin did not induce the HSR, instead, it promoted the degradation of Hsp70 through the lysosome-autophagy pathway. Remarkably, capsaicin did not induce degradation of the constitutively expressed cognate Hsc70, indicating selectivity for Hsp70. Combined treatments of capsaicin and the Hsp90 inhibitor 17-AAG improved the anti-tumor efficacy of 17-AAG in cell culture and tridimensional tumor spheroid growth assays using breast and prostate cancer models. Consistent with this, in silico docking studies revealed that capsaicin binding to the ATP binding site of Hsp90 was distinct from classical N-terminus Hsp90 inhibitors, indicating a novel mechanism of action. Collectively, these findings support the use of capsaicin as a chemical scaffold to develop novel Hsp90 N-terminus inhibitors as well as its ability to be a potential cancer co-therapeutic.

The Pro-Tumorigenic Role of Chemotherapy-Induced Extracellular HSP70 from Breast Cancer Cells via Intratumoral Macrophages

Tumor-associated macrophages (TAMs) contribute to tumor progression and chemoresistance; it is therefore important to clarify the altered functions of macrophages following chemotherapy. While extracellular heat shock protein (HSP) 70 is associated with therapeutic resistance, the effects of HSP70 on TAMs remain largely unknown. Here, we conducted in vitro experiments and immunohistochemistry in 116 breast carcinoma specimens to determine whether the secretion of HSP70 from breast cancer cells following chemotherapy affects macrophage function. It was revealed that the interaction of epirubicin (EPI)-exposed breast cancer cells with macrophages enhanced tumor progression, and EPI promoted the secretion of extracellular HSP70 from breast cancer cells. The expression of pro-tumorigenic macrophage marker CD163 was decreased in macrophages treated with a conditioned medium (CM) from HSP70-silenced breast cancer cells. Breast cancer cells treated with CM from HSP70-silenced breast cancer cells showed decreased expression of transforming growth factor (TGF)-β, and the pro-tumorigenic effects of macrophages were impaired when TGF-β signaling was inhibited. Immunohistochemistry demonstrated that HSP70 served as a poor prognostic factor in conjunction with macrophage infiltration. It was therefore concluded that extracellular HSP70 levels increased following chemotherapy and enhanced the pro-tumorigenic effects of TAMs, either directly or indirectly, by regulating TGF-β expression in breast cancer cells.

The circulating 70 kDa heat shock protein (HSPA1A) level is a potential biomarker for breast carcinoma and its progression

The early diagnosis of breast cancer can improve treatment and prognosis. We sought to evaluate whether the serum concentration of the 70 kDa heat shock protein (HSPA1A) was elevated in Brazilian women with breast cancer, and if levels correlated with tumor characteristics. This was a cross-sectional, analytical, case–control exploratory study performed at The University of São Paulo School of Medicine. From September 2017 to December 2018, 68 women with breast cancer and 59 controls were recruited. The HSPA1A concentration in serum samples was determined by ELISA by individuals blinded to the clinical data. The mean ages in the study and control groups were 54.9 and 52.0 years, respectively. The median serum levels of HSPA1A were elevated in women with breast cancer (1037 pg/ml) compared with controls (300 pg/ml) (p < 0.001). Elevated HSPA1A levels were associated with advanced histological tumor grade (p < 0.001) and with the cell proliferation index (KI67) (p = 0.0418). The HSPA1A concentration was similar in women with different histological subtypes, nuclear grade, hormone receptor expression, HER2 status and the presence or absence of angiolymphatic invasion. Elevated serum HSPA1A in Brazilian women with advanced histological grade and proliferation index breast cancer supports the potential value of additional investigation on larger and more varied populations to verify the value of HSPA1A detection as a component of breast cancer diagnosis and progression.

Combination of second-generation proteasome inhibitor Carfilzomib with Bortezomib in four different breast cancer cell lines

BACKGROUND

Proteasome inhibitors target different pathways in cells and therefore are promising drugs in cancer therapy. The use of these inhibitors is approved mainly in hematological cancers, and recently many clinical trials and preclinical studies are running for efficacy in solid tumors. Carfilzomib is a second generation inhibitor and developed to decrease the side effects of bortezomib. Although there are many valid therapies in breast cancer, resistance and recurrence are inevitable in many cases and the proteasomal system plays an important roles in related pathways.

OBJECTIVE

This study is a preliminary work to evaluate the combination effects of bortezomib and carfilzomib in four different breast cancer cells.

METHODS

MDA-MB-231, MCF-7, UACC-2087, and SKBR-3 cell lines were used. Cell viability was determined by using bortezomib and carfilzomib alone and in combination. Combination effect values were determined using the Chou-Talalay method. Apoptosis, proteasome activity, cleaved PARP, and HSP70 expressions were analyzed in the determined doses.

RESULTS

The response to the combination of the two inhibitors was different in four cell lines. Apoptosis was significantly higher in combination groups compared to carfilzomib in three cell lines except SKBR-3, and higher in combination group compared to bortezomib only in UACC-2087. Combination decreased cleaved PARP levels in MDA-MB-231 and MCF-7 and increased in SKBR-3 compared to bortezomib. HSP70 levels decreased in combination with UACC-2087 and SKBR-3 compared to carfilzomib.

CONCLUSION

Taken together, the combination of the two inhibitors was more apoptotic compared to carfilzomib and apoptosis was higher only in UACC-2087 compared to bortezomib. This apoptosis data can not be directly correlated to degree of proteaasome inhibiton, PARP cleavage and HSP70 response.

Clinicopathological significance of HSP70 expression in gastric cancer: a systematic review and meta-analysis

Background

Heat shock protein 70 (HSP70) has been associated with the clinicopathological characteristics and prognosis of many cancers types, implying that it is a potential cancer biomarker. However, no consensus has been reached regarding its clinicopathological and prognostic significance in patients with gastric cancer. To address this gap, we performed a systematic review and meta-analysis.

Methods

We searched PubMed, Embase, and the Cochrane Library for full-text literature according to the eligibility criteria. We used the odds ratio and hazard ratio as the suitable parameters to evaluate the clinicopathological and prognostic significance of HSP70. The statistical analysis was performed using STATA 15.0.

Results

After inclusion and exclusion of studies based on the eligibility criteria, data of 1,307 patients with gastric cancer from 9 studies were finally included. The pooled outcomes implied that HSP70 expression was significantly correlated with higher differentiation degrees, intestinal gastric cancer, and lymphovascular invasion but not with age, gender, depth of invasion, Helicobacter pylori infection, lymph node invasion, TNM stages, and metastasis. The pooled HR showed no significant correlation between HSP70 expression and overall survival of gastric cancer patients.

Conclusions

Our meta-analysis showed that HSP70 plays a complicated role in the development of gastric cancer. It may be directly engaged in tumour differentiation and distant invasion but cannot be considered a biomarker for predicting the prognosis of gastric cancer.

Chlorpyrifos induces cell proliferation in MCF-7 and MDA-MB-231 cells, through cholinergic and Wnt/β-catenin signaling disruption, AChE-R upregulation and oxidative stress generation after single and repeated treatment

Chlorpyrifos (CPF) biocide, is associated with breast cancer. The processes underlying this association have not been elucidated to date. CPF increases MCF-7 and MDA-MB-231 cell proliferation after acute and long-term treatment, partially through KIAA1363 overexpression and aryl-hydrocarbon receptor activation but also through estrogen receptor-alpha activation after 24 h exposure in MCF-7 cells, suggesting other mechanisms may be involved. CPF induces reactive oxygen species (ROS) generation, acetylcholine accumulation, and overexpression of acetylcholinesterase-R/S (AChE-R/S) variants, while it also alters the Wnt/β-catenin pathway, both in vitro and in vivo, in processes different from cancer. These latter mechanisms are also linked to cell proliferation and could mediate this effect induced by CPF. Our results show that CPF (0.01-100 μM), following one-day and fourteen-days treatment, respectively, induced ROS generation and lipid peroxidation, and acetylcholine accumulation due to AChE inhibition, Wnt/β-catenin up- or downregulation depending on the CPF treatment concentration, and AChE-R and AChE-S overexpression, with the latter being mediated through GSK-3β activity alteration. Finally, CPF promoted cell division through ACh and ROS accumulation, AChE-R overexpression, and Wnt/β-catenin signaling disruption. Our results provide novel information on the effect of CPF on human breast cancer cell lines that may help to explain its involvement in breast cancer.

The Prognostic Significance of Hsp70 in Patients with Colorectal Cancer Patients: A PRISMA-Compliant Meta-Analysis

Background

Hsp70 (heat shock protein 70) plays a key role in carcinogenesis and cancer progression. However, the relationship between the Hsp70 expression level and the colorectal cancer patient survival is unknown. This study is aimed at investigating the relationship between Hsp70 and the prognosis of colorectal carcinoma patients.

Methods

PubMed, Web of Science, and Embase were used for systematic computer literature retrieval. Stata SE14.0 software was used for quantitative meta-analysis. Besides, data was extracted from selected articles. Relationships between Hsp70 expression level and prognosis were further studied. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were also computed.

Results

A total of 11 potentially eligible studies with 2269 patients were identified in 10 tumors from PubMed, Web of Science, and Embase. Hsp70 overexpression was associated with poor overall survival (OS) and disease-free survival (DFS) in colorectal carcinoma patients (HRs, 0.65 (95% CI: 0.52-0.78) and 0.77 (95% CI: 0.23-1.32), respectively).

Conclusions

Hsp70 overexpression can predict poor survival in colorectal cancer patients.

Amino Acid Transporter SLC6A14 (ATB0,+) - A Target in Combined Anti-cancer Therapy

Cancer cells are characterized by quick growth and proliferation, demanding constant supply of various nutrients. Several plasma membrane transporters delivering such compounds are upregulated in cancer. Solute carrier family 6 member 14 (SLC6A14), known as amino acid transporter B^0,+ (ATB^0,+) transports all amino acids with exception of the acidic ones: aspartate and glutamate. Its malfunctioning is correlated with several pathological states and it is upregulated in solid tumors. The high expression of SLC6A14 is prognostic and unfavorable in pancreatic cancer, while in breast cancer it is expressed in estrogen receptor positive cells. As many plasma membrane transporters it resides in endoplasmic reticulum (ER) membrane after translation before further trafficking through Golgi to the cell surface. Transporter exit from ER is strictly controlled. The proper folding of SLC6A14 was shown to be controlled from the cytoplasmic side by heat shock proteins, further exit from ER and formation of coatomer II (COPII) coated vesicles depends on specific interaction with COPII cargo-recognizing subunit SEC24C, phosphorylated by kinase AKT. Inhibition of heat shock proteins, known to be upregulated in cancer, directs SLC6A14 to degradation. Targeting proteins regulating SLC6A14 trafficking is proposed as an additional pharmacological treatment of cancer.

Chlorpyrifos-induced cell proliferation in human breast cancer cell lines differentially mediated by estrogen and aryl hydrocarbon receptors and KIAA1363 enzyme after 24 h and 14 days exposure

Organophosphate biocide chlorpyrifos (CPF) is involved with breast cancer. However, the mechanisms remain unknown. CPF increases cell division in MCF-7 cells, by estrogen receptor alpha (ERα) activation, although it is a weak ERα agonist, suggesting other mechanisms should be involved. Aromatic hydrocarbon receptor (AhR) activation increases cell division in human breast cancer cells, and CPF strongly activates it. Finally, the KIAA1363 enzyme, which is regulated by CPF, is overexpressed in cancer cells. Accordingly, we hypothesized that CPF or its metabolite chlorpyrifos-oxon (CPFO) could induce cell viability promotion in MCF-7 and MDA-MB-231 cell lines, through mechanisms related to ERα, AhR, and KIAA1363, after 24 h and 14 days treatment. Results show that, after acute and long-term treatment, CPF and CPFO alter differently KIAA1363, AhR, ER and cytochrome P450 isoenzyme 1A1 (CYP1A1) expression. In addition, they induced cell proliferation through ERα activation after 24 h exposure in MCF-7 cells and through KIAA1363 overexpression and AhR activation in MCF-7 and MDA-MB-231 cells after acute and long-term treatment. The results obtained in this work provide new information relative to the mechanisms involved in the CPF toxic effects that could lead to breast cancer disease.

Drug-induced keratin 9 interaction with Hsp70 in bladder cancer cells

A pull-down experiment (co-immunoprecipitation) was performed on a T24 human bladder cancer cell lysate treated with the Hsp inhibitor VER155008 using an Hsp70 antibody attached to Dynabeads. Keratin 9, a cytoskeleton intermediate filament protein, was identified by LC MS/MS analysis. This novel finding was confirmed by Western blotting, RT-PCR, and immunocytochemistry. Other members of the keratin family of proteins have been shown to be involved in cancer progression, most recently identified to be associated with cell invasion and metastasis. The specific role of keratin 9 expression in these cells is yet to be determined.

Identification of peculiar gene expression profile in peripheral blood mononuclear cells (PBMC) of celiac patients on gluten free diet

Celiac disease (CD) is a systemic disorder characterized by an immune-mediated reaction to gluten and a wide spectrum of clinical manifestations. Currently, the main treatment of CD is represented by adherence to a gluten-free diet (GFD) which determines the resolution of symptoms, and the normalization of the serology and of the duodenal villous atrophy. In the present study, we aimed to identify changes in gene expression in peripheral blood mononuclear cells (PBMCs) of celiac patients on GFD for at least 2 years, in order to identify novel disease biomarkers and candidate targets for putative therapeutic approaches. Microarray analysis was performed on PBMCs from 17 celiac patients on long-term GFD and 20 healthy controls. We identified 517 annotated genes that were significantly modulated between celiac patients and controls. Significant biological pathways were functionally clustered using the Core Function of Ingenuity System Pathway Analysis (IPA). Intriguingly, despite being on a GFD, celiac patients exhibited a peculiar PBMC profile characterized by an aberrant expression of genes involved in the regulation of immunity, inflammatory response, metabolism, and cell proliferation. Random forest algorithm was then used to validate the prediction ability of core genes as classifiers of the "celiac status". In conclusion, our study identified a characteristic PBMCs signature profile in clinically asymptomatic celiac patient.

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.

Nuclear heat shock protein 110 expression is associated with poor prognosis and hyperthermo-chemotherapy resistance in gastric cancer patients with peritoneal metastasis

AIM

To investigate the significance of heat shock protein 110 (HSP110) in gastric cancer (GC) patients with peritoneal metastasis undergoing hyperthermo-chemotherapy.

METHODS

Primary GC patients (n = 14) with peritoneal metastasis or positive peritoneal lavage cytology who underwent distal or total gastrectomy between April 2000 and December 2011 were enrolled in this study. The patients underwent postoperative intraperitoneal hyperthermo-chemotherapy using a Thermotron RF-8 heating device two weeks after surgery. We analyzed nuclear HSP110 expression in surgically resected tumors using immunohistochemistry. Additionally, the effect of HSP110 suppression on hyptherthermo-chemosensitivity was assessed in vitro in the MKN45 GC cell line using the HSP inhibitor KNK437.

RESULTS

HSP110 immnohistochemical staining in 14 GC patients showed that five (35.7%) samples belonged to the low expression group, and nine (64.3%) samples belonged to the high expression group. Progression-free survival was significantly shorter in the HSP110 high-expression group than in the low-expression group (P = 0.0313). However, no significant relationships were identified between HSP110 expression and the clinicopathological characteristics of patients. Furthermore, high HSP110 expression was not an independent prognostic factor in GC patients with peritoneal metastasis (P = 0.0625). HSP110 expression in MKN45 cells was suppressed by KNK437 at the hyperthermic temperature of 43 °C in vitro. Comparison of MKN45 cell proliferation in the presence and absence of KNK437 at 43 °C, revealed that proliferation was significantly decreased when HSP110 was inhibited by KNK437. Additionally, HSP110 suppression via HSP inhibitor treatment increased cellular sensitivity to hyperthermo-chemotherapy in vitro.

CONCLUSION

The expression of nuclear HSP110 in GC patients might be a new marker of chemosensitivity and a therapeutic target for patients who are tolerant to existing hyperthermo-chemotherapies.

CLEC14a-HSP70-1A interaction regulates HSP70-1A-induced angiogenesis

CLEC14a (C-type lectin domain family 14 member) is a tumor endothelial cell marker protein that is known to play an important role in tumor angiogenesis, but the basic molecular mechanisms underlying this function have not yet been clearly elucidated. In this study, using various proteomic tools, we isolated a 70-kDa protein that interacts with the C-type lectin-like domain of CLEC14a (CLEC14a-CTLD) and identified it as heat shock protein 70-1A (HSP70-1A). Co-immunoprecipitation showed that HSP70-1A and CLEC14a interact on endothelial cells. In vitro binding analyses identified that HSP70-1A specifically associates with the region between amino acids 43 and 69 of CLEC14a-CTLD. Competitive blocking experiments indicated that this interacting region of CLEC14a-CTLD significantly inhibits HSP70-1A-induced extracellular signal-regulated kinase (ERK) phosphorylation and endothelial tube formation by directly inhibiting CLEC14a-CTLD-mediated endothelial cell-cell contacts. Our data suggest that the specific interaction of HSP70-1A with CLEC14a may play a critical role in HSP70-1A-induced angiogenesis and that the HSP70-1A-interacting region of CLEC14a-CTLD may be a useful tool for inhibiting HSP70-1A-induced angiogenesis.

Heat shock-induced HIKESHI protects cell viability via nuclear translocation of heat shock protein 70

Heat shock proteins (HSPs), particularly HSP70, help restore normal cellular function following damage caused by stressors. HSP expression in tumor tissues indicates cancer progression, and while the development of HSP inhibitors is progressing, these substances are not widely used to treat cancer. HIKESHI (C11orf73) does not control the intracellular movement of HSP70 at normal temperatures; however, it does regulate the function and movements of HSP70 during heat shock. In this study, we examined the intracellular movement of HSP70 during heat shock to investigate the significance of HIKESHI expression in gastric cancer (GC) and determine if HIKESHI inhibition has cytotoxic effects. We examined HIKESHI using GC cell lines and immunostaining in 207 GC tissue samples. HIKESHI expression in GC tissues was associated with the progression of lymphatic invasion. Suppressing HIKESHI using siRNA did not affect cell viability at normal temperatures. However, suppressing HIKESHI during heat shock inhibited HSP70 nuclear transport and suppressed cell viability. Our results suggest that HIKESHI is a marker of cancer progression and that the combination of HIKESHI inhibition and hyperthermia is a therapeutic tool for refractory GC.

Heat shock protein 70 downregulation inhibits proliferation, migration and tumorigenicity in hepatocellular carcinoma cells

The overexpression of heat shock protein 70 (HSP70), a major stress-inducible heat shock protein, has been identified to enhance the proliferation, survival, invasion and metastasis of diverse types of human cancer. However, its role in hepatocellular carcinoma (HCC) remains poorly understood. The present study demonstrated that HSP70 expression was higher in tested HCC cell lines, compared with the normal hepatocyte LO2, and the suppression of HSP70 significantly inhibited the proliferation of SMMC-7721 and Hep3B cells. The growth inhibitory effect was mediated by cell cycle arrest at the G₁/S phase with reduced cyclin D1 and increased p27Kip1 expression. Furthermore, HSP70 knockdown significantly inhibited the migration and invasion abilities of HCC cells. In conclusion, HSP70 is a key regulator involved in the proliferation, migration and invasion of HCC, and it may be used as a potential therapeutic target for HCC.

Nuclear heat shock protein 110 expression is associated with poor prognosis and chemotherapy resistance in gastric cancer

Heat shock protein (HSP) expression is induced by the exposure to stress, such as fever, oxidative stress, chemical exposure, and irradiation. In cancer, HSP promotes the survival of malignant cells by inhibiting the induction of apoptosis. In colorectal cancer, a loss-of-function mutation of HSP110 (HSP110ΔE9) has been identified. HSP110ΔE9 inhibits the nuclear translocation of wild-type HSP110, which is important for its chaperone activity and anti-apoptotic effects. The patients carrying HSP110ΔE9 mutation exhibit high sensitivity to anticancer agents, such as oxaliplatin and 5-fluorouracil. There is still insufficient information about HSP110 localization, the clinicopathological significance of HSP110 expression, and its association with chemotherapy resistance in gastric cancer. Here, we found that high nuclear expression of HSP110 in gastric cancer tissues is associated with cancer progression, poor prognosis, and recurrence after adjuvant chemotherapy. In vitro results showed that HSP110 suppression increases the sensitivity to 5-fluorouracil and cisplatin of human gastric cancer cell lines. Our results suggest that nuclear HSP110 may be a new drug sensitivity marker for gastric cancer and a potential molecular therapeutic target for the treatment of gastric cancer patients with acquired anticancer drug resistance.

Elevated serum levels of heat shock protein 70 are associated with breast cancer

Breast cancer (BC) is the most frequent cause of cancer death in women throughout the world. Thus, it is necessary to establish sensitive screening, diagnosis and treatment methods for BC. Heat shock protein 70 (HSP70) is an important cellular stress response protein that protects cells from apoptosis. Recent studies have shown that serum HSP70 levels may provide clinically important information in various types of cancer. HSP70 is also overexpressed in BC, which is known to be associated with cancer progression, apoptosis and cell proliferation. However, the serum level of HSP70 and its diagnostic and prognostic potential in BC have not been investigated yet. The aim of this study was to determine the usefulness of serum HSP70 level as a diagnostic test and its predictive value in patients with BC. This prospective study consisted of 45 female patients diagnosed with BC and 16 healthy women who were matched for age and body mass index (BMI). Enzyme-linked immunosorbent assay (ELISA) technique was used to measure the serum level of HSP70. The serum level of HSP70 was significantly higher in patients with BC than in the healthy control group (5.98 ± 2.05 vs. 1.49 ± 0.47 ng/ml, p = 0.001). HSP70 level > 2.41 ng/ml was the best cutoff value to predict BC (97.78% sensitivity and 93.75% specificity). This study shows that HSP70 can be used as an adjunct to other diagnostic tests for BC and may be helpful for identifying patients at increased risk of BC.

Aptamer-Enabled Manipulation of the Hsp70 Chaperone System Suggests a Novel Strategy for Targeted Ubiquitination

The Hsp70 chaperone system plays an important role in protein quality control by assisting in the folding and clearance of misfolded proteins. However, the mechanism by which it chooses between folding and degradation pathways is not fully understood. In this study, we used an RNA aptamer for Hsp70 to perturb the function of Hsp70 in cell-free systems. We found that the aptamer inhibited both Hsp70-mediated folding and Hsp70-CHIP-mediated ubiquitination/degradation of a misfolded protein substrate. Based on these results, we explored a novel strategy for targeted protein ubiquitination, using an engineered bifunctional aptamer to tether a protein substrate to Hsp70. We demonstrated that increased Hsp70-CHIP-mediated ubiquitination of the tethered protein substrate can be specifically induced by this bifunctional aptamer. This strategy may be useful in selective degradation of disease-causing proteins for therapeutic purposes. In addition, these studies provide insight into the mechanism of Hsp70-mediated protein triage.

HSP70 expression in dentigerous cyst, odontogenic keratocyst, and ameloblastoma

Heat shock proteins (HSPs) work as molecular chaperones that can assist cells to deal with stressful situations. Members of the HSP70 family can regulate cell growth and transformation and are involved in the maintenance of cellular homeostasis. In view of the distinct clinical behavior of odontogenic lesions, the objective of the present study was to investigate the immunohistochemical expression of HSP70 in these lesions. In this study, 70 formalin-fixed paraffin-embedded tissue blocks of odontogenic lesion-16 unicystic ameloblastomas (UAs), 17 solid ameloblastomas (SAs), 18 odontogenic keratocysts (OKCs), and 19 dentigerous cysts (DCs)-were reviewed by immunohistochemistry for HSP70 staining. In this study, HSP70 immunostaining was evident in all groups of the specimen. Mean percentage of HSP70 staining in SAs (84.2 ± 11.3) and OKCs (83.4 ± 6.8) were significantly higher than UAs (64.4 ± 9.8) and DCs (12.6 ± 10.2) (p = 0.00). But, there was no statistically significant difference between HSP70 expression in SAs and OKCs. The result of this study proposes that high expression rate of HSP70 has a role in the pathogenesis of ameloblastoma and OKC and is one of the reasons for the aggressive behavior of ameloblastoma and high recurrence role of OKC, reinforcing the classification of OKC as an odontogenic tumor.

Label-free LC-MS analysis of HER2+ breast cancer cell line response to HER2 inhibitor treatment

BACKGROUND

Human epidermal growth-factor receptor (HER)-2 is overexpressed in 25 % of breast-cancers and is associated with an aggressive form of the disease with significantly shortened disease free and overall survival. In recent years, the use of HER2-targeted therapies, monoclonal-antibodies and small molecule tyrosine-kinase inhibitors has significantly improved the clinical outcome for HER2-positive breast-cancer patients. However, only a fraction of HER2-amplified patients will respond to therapy and the use of these treatments is often limited by tumour drug insensitivity or resistance and drug toxicities. Currently there is no way to identify likely responders or rational combinations with the potential to improve HER2-focussed treatment outcome.

METHODS

In order to further understand the molecular mechanisms of treatment-response with HER2-inhibitors, we used a highly-optimised and reproducible quantitative label-free LC-MS strategy to characterize the proteomes of HER2-overexpressing breast-cancer cell-lines (SKBR3, BT474 and HCC1954) in response to drug-treatment with HER2-inhibitors (lapatinib, neratinib or afatinib).

RESULTS

Following 12 ours treatment with different HER2-inhibitors in the BT474 cell-line; compared to the untreated cells, 16 proteins changed significantly in abundance following lapatinib treatment (1 μM), 21 proteins changed significantly following neratinib treatment (150 nM) and 38 proteins changed significantly following afatinib treatment (150 nM). Whereas following 24 hours treatment with neratinib (200 nM) 46 proteins changed significantly in abundance in the HCC1954 cell-line and 23 proteins in the SKBR3 cell-line compared to the untreated cells. Analysing the data we found that, proteins like trifunctional-enzyme subunit-alpha, mitochondrial; heterogeneous nuclear ribonucleoprotein-R and lamina-associated polypeptide 2, isoform alpha were up-regulated whereas heat shock cognate 71 kDa protein was down-regulated in 3 or more comparisons.

CONCLUSION

This proteomic study highlights several proteins that are closely associated with early HER2-inhibitor response and will provide a valuable resource for further investigation of ways to improve efficacy of breast-cancer treatment.

Oxidative stress and cell damage in a model of precancerous lesions and advanced hepatocellular carcinoma in rats

Hepatocellular carcinoma (HCC) is the third most frequent cause of cancer deaths throughout the world. This study was aimed to analyze oxidative stress and cell damage in a multistage model of liver carcinogenesis induced by diethylnitrosamine (DEN) in rats. Male Wistar rats weighing 145–150 g were divided into three groups: control, precancerous lesions (PL) (which received 100 mg DEN once a week every 6 weeks up to 28 weeks), and advanced HCC (50 mg DEN once/twice per week up to 19 weeks). Lipid peroxidation (TBARS), superoxide dismutase (SOD) activity, and expression of transforming growth factor-1 beta (TGF)-1β, endothelial and inducible nitric oxide syntahese (eNOS, iNOS), NADPH quinone oxireductase (NQO)-1, nuclear factor erythroid 2-related factor (NrF)2, kelch-like ECH-associated protein (Keap)1 and heat shock protein (HSP)70 were measured. TBARS concentration was augmented in the PL and advanced HCC groups. SOD activity, TGF-1β and Nrf2 expression were higher in animals with precancerous lesions. In advanced HCC, expression of NQO1 and iNOS increased while there was a decrease in HPS70 expression. Data obtained provide evidence for the differential activation of proteins involved in oxidative stress and cell damage during progression of carcinogenesis in an animal model of HCC.

The expression of FAS-associated factor 1 and heat shock protein 70 in ovarian cancer

OBJECTIVE

In this study, we evaluated the expression of FAS-associated factor 1 (FAF1) and heat shock protein 70 (HSP70) in normal ovary and ovarian cancer, and also analyzed the correlation between FAF1 and HSP70 in ovarian cancer.

METHODS

The patient group consisted of 29 unrelated Korean women diagnosed as ovarian cancers and control samples were obtained from 7 patients who underwent oophorectomy for benign disease of uterus, and normal ovary was confirmed histologically from biopsy. We examined FAF1 and HSP70 expression by western blot analysis and immunohistochemical staining in normal ovary and ovarian cancer. Furthermore, we examined a correlation between FAF1 and HSP70 in ovarian cancer.

RESULTS

The expression of FAF1 was lower in ovarian cancer than that in normal ovary (P=0.02), and the expression of HSP70 was increased in ovarian cancer in comparison to that in normal ovary (P=0.03). The expression of FAF1 was decreased in advanced stages (stage III or stage IV) as compared with early stages (stage I or stage II) (P=0.01). The expression of HSP70 was not significantly related with ovarian cancer histology (P=0.10), but the expression of HSP70 was most increased with papillary serous carcinomas and undifferentiated ovarian cancer. The expression of FAF1 was inversely correlated with the expression of HSP70 in ovarian cancer (Spearman correlation coefficience=-0.47).

CONCLUSION

We concluded that the expression of FAF1 or HSP70 each seems to have a meaning as a biomarker for early detection of ovarian cancer. The expressions of FAF1 and HSP70 seem to be more valuable in predicting ovarian cancer when used together because of their inverse correlation. This is the first study about the expression of FAF1 in ovarian cancer and the correlation between FAF1 and HSP70 expression in ovarian cancer.

Heat shock protein 70 (HSP70) expression is associated with poor prognosis in intestinal type gastric cancer

Heat shock protein 70 (HSP70) is a molecular chaperone which plays an important role in cellular protection against various stressful stimuli and in the regulation of cellular growth and apoptosis. This study was conducted in gastric carcinoma (GC) to assess correlations of HSP70 expression with clinicopathological parameters and overall survival (OS). Tissue microarray blocks were constructed from 172 GCs and immunohistochemically stained for HSP70. Low HSP70 expression was found in 122 GCs (71 %), whereas 50 (29 %) had high expression. HSP70 expression was higher in tumours in the cardia (p = 0.008), with non-signet ring cell histology (p < 0.001), of intestinal type (p = 0.045) and of higher pathological T stage (p = 0.026). When considering the cohort as a whole, HSP70 expression did not correlate with OS (p = 0.092). In intestinal type carcinomas, however, high HSP70 expression significantly correlated with worse OS (p = 0.034). These results suggest that HSP70 expression might be an unfavourable prognostic factor in patients with GC, especially of intestinal type.

The HSP70 family and cancer

The HSP70 family of heat shock proteins consists of molecular chaperones of approximately 70kDa in size that serve critical roles in protein homeostasis. These adenosine triphosphatases unfold misfolded or denatured proteins and can keep these proteins in an unfolded, folding-competent state. They also protect nascently translating proteins, promote the cellular or organellar transport of proteins, reduce proteotoxic protein aggregates and serve general housekeeping roles in maintaining protein homeostasis. The HSP70 family is the most conserved in evolution, and all eukaryotes contain multiple members. Some members of this family serve specific organellar- or tissue-specific functions; however, in many cases, these members can function redundantly. Overall, the HSP70 family of proteins can be thought of as a potent buffering system for cellular stress, either from extrinsic (physiological, viral and environmental) or intrinsic (replicative or oncogenic) stimuli. As such, this family serves a critical survival function in the cell. Not surprisingly, cancer cells rely heavily on this buffering system for survival. The overwhelming majority of human tumors overexpress HSP70 family members, and expression of these proteins is typically a marker for poor prognosis. With the proof of principle that inhibitors of the HSP90 chaperone have emerged as important anticancer agents, intense focus has now been placed on the potential for HSP70 inhibitors to assume a role as a significant chemotherapeutic avenue. In this review, the history, regulation, mechanism of action and role in cancer of the HSP70 family are reviewed. Additionally, the promise of pharmacologically targeting this protein for cancer therapy is addressed.

Increased inducible heat shock protein 72 expression associated with PBMC isolated from patients with haematological tumours

BACKGROUND

Heat shock protein 72 (Hsp72) is a highly inducible stress protein and molecular chaperone. Cancers have been shown to be associated with increased Hsp72 expression within the tumour itself and this may lead to resistance to apoptosis.

METHODS

Peripheral blood mononuclear cells (PBMC) were isolated from patients diagnosed with chronic lymphocytic leukaemia (CLL) (n = 27) and chronic myelomonocytic leukaemia (CMML) (n = 16) and Hsp72 expression was characterized on both the cell surface and intracellularly by flow cytometry. To allow for comparison PBMC from breast cancer patients (n = 25) and healthy volunteers (n = 19) were included.

RESULTS

Both lymphocytes and monocytes from CLL and CMML patients showed high levels of total Hsp72 expression (4-6 fold increase) in comparison to breast cancer and healthy subjects. The majority of Hsp72 in these tumours was determined to be cell-surface expressed (64-93% of cell total Hsp72).

CONCLUSIONS

A correlation was observed between lymphocyte and monocyte total Hsp72 expression (p < 0.001) suggesting a common stress response pathway may exist in these blood cells and there are stress conditions present within the circulation. Hsp72 expression was not found to be related to white blood cell count.

Nuclear Ago2/HSP60 contributes to broad spectrum of hATSCs function via Oct4 regulation

AIMS

Argonaute2 (Ago2) plays a fundamental role in microRNA-mediated gene regulation through its intrinsic endonuclease activity. In this study we demonstrate the novel functions and molecular mechanisms by which nuclear Ago2 directly regulates HSP (heat shock protein) 60 expression and stem cell self-renewal. HSP60 is a crucial regulator of ROS (reactive oxygen species), senescence, and apoptotic cell death in several tissues and cell types.

RESULTS

HSP60 is regulated via inactivation of p38/JNK and p53 and binds directly to the regulatory regions of the TERT, c-myc, GPx3, p53, and STAT3 genes. Using HSP60 CHIP-PCR experiments, we show that HSP60 binds directly to the Oct4 and Nanog genes and directly regulates Oct4 and other stemness genes involved in human adipose tissue-derived stem cell (hATSC) differentiation. HSP60 also positively regulates ROS-scavenging factors, including GPx3 and TXNL1, which directly modulate cytosolic ROS in hATSCs. Moreover, our study shows that Oct4 regulates HSP60 expression and controls hATSC survival and self-renewal after binding to the HSP60 gene. Furthermore, HSP60-mediated regulation of Oct4 contributes to neuronal and endodermal β-cell differentiation of hATSCs in vitro and in vivo and downregulates mesoderm-specific gene expression.

INNOVATION AND CONCLUSION

We show that increased levels of Ago2 or HSP60 effectively induce nuclear localization of HSP60, which directly controls Oct4, c-Myc, p53, TERT, and STAT3 for transdifferentiation programs. Collectively, we suggest a novel model in which nuclear Ago2 controls HSP60 in hATSCs.

Down-regulated expression of HSP70 in correlation with clinicopathology of cholangiocarcinoma

Cholangiocarcinoma is a crucial health problem in northeast Thailand. Although rare, it is a highly fatal disease and the prognosis of CCA patients is very poor. To determine if expression of specific genes is useful for diagnosis and prognosis for CCA. We examined the expression of HSP70, HSP90, RB1, cyclin D1, and HDAC6 in 50 resections of human CCA tissues by quantitative real-time PCR. The expression of HSP70, RB1, and HDAC6 was "dominant down-regulation," while the expression of cyclin D1 and HSP90 was "dominant up-regulation." There were no correlations between RB1, cyclin D1, HSP90, and clinicopathological parameters such as status, histology type, histological grading, stage of CCA, and metastasis. A significant association was found between HDAC6 and CCA staging (p = 0.000), CCA gross type and HSP70 (p = 0.046) as well as RB1 expression (p = 0.046). Patients with down-regulation of HSP70 had significantly poorer prognosis than those in the up-regulation group (p = 0.002). Expression of HSP70 may be useful as a new prognostic marker for CCA.

Using proteomic approach to identify tumor-associated proteins as biomarkers in human esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in China. The lower survival rate of ESCC is attributed to late diagnosis and poor therapeutic efficacy; therefore, the identification of tumor-associated proteins as biomarkers for early diagnosis, and the discovery of novel targets for therapeutic intervention, seems very important for increasing the survival rate of ESCC. To identify tumor-associated proteins as biomarkers in ESCC, we have analyzed ESCC tissues and adjacent normal tissues by two-dimensional electrophoresis (2DE) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The results showed that a total of 104 protein spots with different expression levels were found on 2DE, and 47 proteins were eventually identified by MALDI-TOF MS. Among these identified proteins, 33 proteins including keratin 17 (KRT17), biliverdin reductase B (BLVRB), proteasome activator subunit 1 (PSME1), manganese superoxide dismutase (MnSOD), high-mobility group box-1(HMGB1), heat shock protein 70 (HSP70), peroxiredoxin (PRDX1), keratin 13 (KRT13), and so on were overexpressed, and 14 proteins including cystatin B (CSTB), tropomyosin 2 (TPM2), annexin 1 (ANX1), transgelin (TAGLN), keratin 19 (KRT19), stratifin (SFN), and so on were down-expressed in ESCC. Biological functions of these proteins are associated with cell proliferation, cell motility, protein folding, oxidative stress, and signal transduction. In the subsequent study using immunoassay on ESCC serum samples and tissue-array slides, two representative proteins, HSP70 and HMGB1, were selected as examples for the purpose of validation. The results showed that both HSP70 and HMGB1 can induce autoantibody response in ESCC sera and have higher expression in ESCC tissues. Especially, the frequency of antibodies to HSP70 in ESCC sera was significantly higher than that in normal human sera. The preliminary results suggest that some of these identified proteins might contribute to esophageal cell differentiation and carcinogenesis, certain proteins could be used as tumor-associated antigen (TAA) biomarkers in cancer diagnosis, and further studies on these identified proteins should provide more evidence of how these proteins are involved in carcinogenesis of ESCC.

Prognostic significance of heat shock protein 70 (HSP70) in patients with oral cancer

Backround

Oral squamous cell carcinoma (OSCC) is characterized by an aggressive growth pattern, local invasiveness, and spread to cervical lymph nodes. Overall survival rates have not improved, primarily due to locoregional tumor recurrences and distant metastasis. To date, no trustworthy or clinically applicable marker of tumor aggressiveness has been identified for OSCC. Heat shock proteins (HSPs) play a role in tumor antigenicity. This study aimed to investigate the expression and prognostic significance of highly stress-inducible HSP70 in OSCC.

Methods

Immunohistochemical staining for HSP70 was performed on surgical specimens obtained from 61 patients with OSCC. Light microscopy and analysis 3.1^® (Soft Imaging System, Münster, Germany), an image processing and analysis program, were used for evaluating HSP70 expression. The tumor region was defined as the region of interest (ROI) and HSP70-positive staining was analyzed.

Results

Immunoreactivity for HSP70 was positive in tumor cells of 38 of all patients (63.3%). Positive immunoreactivity of tumor cells could be detected in 17 of 28 patients with T2 tumors (60.7%) Prognostic significance of HSP70 expression in tumor cells was detected in patients with T2 tumors (p = 0.009).

Conclusions

The survival of patients suffering from T2 tumors with positive HSP70 expression was 8 times higher than that for patients with negative HSP70 expression, suggesting that T1-T2 tumors of OSCC with low expression of HSP70 require more radical treatment.

Serum level of soluble 70-kD heat shock protein is associated with high mortality in patients with colorectal cancer without distant metastasis

Many findings indicate that measuring the serum concentration of soluble 70-kD heat shock protein (soluble HSP70) may provide important information in cardiovascular, inflammatory, and pregnancy-related diseases; however, only scarce data are available in cancer. Therefore, using a commercial ELISA kit, we measured soluble HSP70 concentration in the sera of 179 patients with colorectal cancer. We investigated the relationship between soluble HSP70 concentration and mortality, during 33.0 (24.4-44.0) months long follow-up. High (>1.65 pg/ml, median concentration) soluble HSP70 level was a significant (hazard ratio: 1.88 (1.20-2.96, p = 0.005) predictor of mortality during the follow-up period. When we compared the soluble HSP70 levels in patients with non-resected primary tumors as compared to those who were recruited into the study 4-6 weeks after the tumor resection they were found to be significantly (p = 0.020) higher in the former group. Since the patients with non-resected primary tumors had also distant metastasis and died early, we limited the further analysis to 142 patients with no distant metastasis at the beginning of the follow-up. This association remained significant even after multiple Cox-regression analysis had been performed to adjust the data for age and sex (p = 0.028); age, sex, and TNM-T stage (p = 0.041); age, sex, and TNM-N stage (p = 0.021); age, sex, and histological grade (p = 0.023); or age, sex, and tumor localization (p = 0.029). Further analysis showed that the significant association between high HSP70 levels and poor survival is in the strongest in the group of <70-year-old female patients (HR: 5.52 (2.02-15.15), p = 0.001), as well as in those who were in a less advanced stage of the disease at baseline. These novel findings indicate that the serum level of soluble HSP70 might prove a useful, stage-independent prognostic marker in colorectal cancer without distant metastasis.

Heat shock cognate 70 protein secretion as a new growth arrest signal for cancer cells

Earlier studies indicated that density-arrested cancer cells released an unidentified growth inhibitor whose secretion was prevented by overexpression of the lysosomal protease cathepsin D (cath D). In this study, this growth inhibitor was purified by affinity chromatography and identified as the heat shock cognate 70 protein (hsc70) based on its peptide microsequencing and specific antibody recognition. Among intracellular proteins, including other heat shock proteins, only constitutive hsc70 was secreted in response to the high-cell density. Moreover, hsc70 secretion from cancer cells was generated by serum deprivation, whereas its cellular concentration did not change. Prevention of Hsc70 secretion by cath D overexpression was associated with the formation of multilayer cell cultures, thus indicating a loss of contact inhibition. In addition, we showed that supplementing the culture medium with purified hsc70 inhibited cell proliferation in the nanomolar range. Conversely, removal of this extracellular hsc70 from the medium by either retention on ADP-agarose or competition at the Hsc70 binding site restored cell proliferation. Hsc70 appears active in human breast cancer cells and hypersecreted by direct cath D inhibition. These results suggest a new role of this secreted hsc70 chaperone in cell proliferation that might account for the higher tumor growth of cancer cells overexpressing cath D.

Heat shock proteins in animal neoplasms and human tumours--a comparison

Heat shock proteins (HSPs) are implicated in all phases of cancer from proliferation, impaired apoptosis and sustained angiogenesis to invasion and metastasis. The presence of abnormal HSP levels in several human tumours suggests that these proteins could be used as diagnostic and/or prognostic markers, whilst the direct correlation between HSP expression and drug resistance in neoplastic tissues means they could also be used to predict cancer response to specific treatment. HSPs have also been successfully targeted in clinical trials modifying their expression or chaperone activity. Preliminary studies in veterinary medicine have also demonstrated the presence of altered HSP expression in neoplasms, and the study of carcinogenesis and the role of HSPs in animal models will surely be an additional source of information for clinical cancer research.

Circulating heat shock protein 70 and progression in patients with chronic myeloid leukemia

We evaluated the association of circulating levels of heat shock protein 70 (Hsp70) in plasma with clinical behavior and progression in 139 chronic myeloid leukemia (CML) patients. Circulating Hsp70 levels did not differ significantly between CML patients in the chronic phase (n=93; median 33.24 ng/mL, range 3.89-128.2 ng/mL) and those in the accelerated/blast phase (n=46; median 26.57 ng/mL, range 4.5-114.7 ng/mL). However, overall CML patients had significantly higher levels of Hsp70 than healthy subjects (n=95, median 4.17 ng/mL, range 1.75-24.7 ng/mL) (P<0.001). In chronic phase CML patients, Hsp70 levels above the median were associated with a higher rate of progression to the accelerated/blast phase and a tendency toward shorter survival. Plasma Hsp70 thus could be a potential marker for predicting disease progression in patients with chronic phase CML.

Apoptosis and anti-apoptotic heat shock proteins in canine cutaneous infundibular keratinizing acanthomas and squamous cell carcinomas

Cell stress and death are linked in the neoplastic process, and heat shock proteins appear to play an important role by inhibiting apoptotic pathways. The apoptotic rates in 9 canine infundibular keratinizing acanthomas (IKAs) and 17 canine squamous cell carcinomas (SCCs) were correlated with the immunohistochemical expression of caspase-3 and the antiapoptotic heat shock proteins Hsp27, 72 and 73. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL) method. The absence of a correlation between the TUNEL index and active-caspase-3 expression, a paucity of active-caspase-3-positive cells and Hsp72 over-expression were considered to be indicative of inhibition of apoptosis, and suggestive that inhibition of cell death plays a key role in oncogenesis and tumour growth of some canine skin neoplasms.

Using proteomic approach to identify tumor-associated antigens as markers in hepatocellular carcinoma

Many studies have demonstrated that intracellular proteins, which are involved in carcinogenesis, can provoke autoantibody responses. Therefore, autoantibodies can be used clinically for cancer detection and for proteomic analysis in identification of tumor-associated antigens (TAAs) that are potentially involved in malignant transformation. Liver cancer, especially hepatocellular carcinoma (HCC), is one of the most common tumors in the world. The majority of people with HCC will die within 1 year of its detection. This high case fatality rate can partially be attributed to a lack of diagnostic methods that allow early detection. In the present study, sera from 20 patients with HCC, 30 patients with chronic hepatitis (CH), and 30 patients with liver cirrhosis (LC) as well as sera from 10 normal individuals were used in a proteomic approach to identify HCC-related TAAs. Thirty-four immunoreactive protein spots were excised from the two-dimensional gel electrophoresis (2DE), digested with trypsin, and subsequently analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Of 34 immunoreactive protein spots, 28 were identified. Seventeen of them were not only reactive with serum antibodies in HCC but also with antibodies in pre-HCC conditions, and 11 were only reactive with serum antibodies in HCC but not with antibodies in pre-HCC conditions. In the subsequent analysis, two representative proteins, HSP60 and HSP70, were selected as examples for the validation purpose. The results from immunoassay were consistent with the data from proteomic analysis, supporting our hypothesis that proteins identified with autoantibodies that have been present in precancer conditions may be not appropriate to use as TAA markers in cancer detection.

Serum proteome analysis for profiling protein markers associated with carcinogenesis and lymph node metastasis in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), one of the most common cancers in population with Chinese or Asian progeny, poses a serious health problem for southern China. It is unfortunate that most NPC victims have had lymph node metastasis (LNM) when first diagnosed. We believe that the 2D based serum proteome analysis can be useful in discovering new biomarkers that may aid in the diagnosis and therapy of NPC patients. To filter the tumor specific antigen markers of NPC, sera from 42 healthy volunteers, 27 non-LNM NPC patients and 37 LNM NPC patients were selected for screening study using 2D combined with MS. Pretreatment strategy, including sonication, albumin and immunoglobulin G (IgG) depletion, was adopted for screening differentially expressed proteins of low abundance in serum. By 2D image analysis and MALDI-TOF-MS identification, twenty-three protein spots were differentially expressed. Three of them were further validated in the sera using enzyme-linked immunosorbent assay (ELISA). Our research demonstrates that HSP70, sICAM-1 and SAA, confirmed with ELISA at sera and immunohistochemistry, are potential NPC metastasis-specific serum biomarkers which may be of great underlying significance in clinical detection and management of NPC.

The heat shock protein 70 family: Highly homologous proteins with overlapping and distinct functions

The human heat shock protein 70 (Hsp70) family contains at least eight homologous chaperone proteins. Endoplasmatic reticulum and mitochondria have their specific Hsp70 proteins, whereas the remaining six family members reside mainly in the cytosol and nucleus. The requirement for multiple highly homologous although different Hsp70 proteins is still far from clear, but their individual and tissue-specific expression suggests that they are assigned distinct biological tasks. This concept is supported by the fact that mice knockout for different Hsp70 genes display remarkably discrete phenotypes. Moreover, emerging data suggest that individual Hsp70 proteins can bring about non-overlapping and chaperone-independent functions essential for growth and survival of cancer cells. This review summarizes our present knowledge of the individual members of human Hsp70 family and elaborate on the functional differences between the cytosolic/nuclear representatives.

TRAIL-induced apoptosis is enhanced by heat shock protein 70 expression

Heat shock protein 70 (Hsp70) is a well-known inhibitor of apoptotic pathways; however, a role for Hsp70 in the modulation of death receptor-mediated apoptosis remains largely unexplored. In this study, the ability of Hsp70 to modulate tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced apoptosis was examined in SW480 and CCRF-CEM cells. These lines exhibit the characteristics of type I cells (SW480, human colon adenocarcinoma), with no requirement for mitochondrial involvement to exhibit apoptosis following death receptor engagement and type II cells (CCRF-CEM, human leukemic T cell), which do require amplification of the signal through the mitochondria. Unexpectedly, expression of Hsp70 in the type II CCRF-CEM cells enhanced the extent of TRAIL-induced apoptosis, but in SW480, Hsp70 had no impact on TRAIL-induced apoptosis. The enhanced TRAIL-induced apoptosis was accompanied by an up-regulation of TRAIL receptors, R1 and R2, at the cell surface as determined by flow cytometry and at the transcriptional level as assessed by real-time polymerase chain reaction (PCR). Increased expression of Hsp70 led to up-regulated expression of p53, and chromatin immunoprecipitation combined with real-time PCR revealed increased binding of p53 to its consensus sequence in the TRAIL-R2 gene. In contrast, expression of Hsp70 in SW480 cells did not increase p53 or TRAIL-R1 or TRAIL-R2 surface expression. This result is in marked contrast to most apoptotic stresses, including TNFalpha and Fas ligand, where Hsp70 has been shown to inhibit apoptosis in type II cells. These findings suggest that in tumors retaining functional p53 and expressing high levels of Hsp70, TRAIL may be an effective therapy.

Docosahexaenoic acid in combination with celecoxib modulates HSP70 and p53 proteins in prostate cancer cells

The role of cyclooxygenase-2 (COX-2) and the mechanism by which it influences the development and behavior of prostate cancer is unclear. Selective COX-2 inhibitors may be effective against prostate cancer via COX-2-independent mechanisms. But administration of high doses of COX-2 inhibitors over longer period of time may not be devoid of side effects. There is increasing interest in using COX-2 inhibitors in combination with other chemopreventive agents to overcome the issue of toxicity. However, the molecular mechanisms underlying their combined actions are not well understood. Therefore, the present study was designed to determine the effects of low doses of docosahexaenoic acid (DHA) in combination with celecoxib on the molecular targets at the proteins level in rat prostate cancer cells. Two-dimensional gel electrophoresis, in combination with mass spectrometry analysis, was used for protein identification. Western blot analysis confirmed the proteins identified. Paraffin-embedded tissue sections from the rat prostate tumor were used to detect base level expression of heat shock protein 70 (HSP70) and p53. The rate of cancer cell growth was inhibited more effectively (p < 0.01) by DHA in combination with celecoxib at lower doses (2.5 microM each). A total number of twelve proteins were differentially expressed by the combined action of DHA and celecoxib at low doses. It was interesting to note that these agents activated both HSP70 and p53 proteins. Activation of HSP70 by the combined actions of DHA and celecoxib in the presence of wild-type p53 reveals a unique COX-2 independent mode of action against prostate cancer.

Synthetic small interfering RNA targeting heat shock protein 105 induces apoptosis of various cancer cells both in vitro and in vivo

We previously reported that heat shock protein 105 (HSP105), identified by serological analysis of a recombinant cDNA expression library (SEREX) using serum from a pancreatic cancer patient, was overexpressed in various human tumors and in the testis of adult men by immunohistochemical analysis. In the present study, to elucidate the biological function of the HSP105 protein in cancer cells, we first established NIH3T3 cells overexpressing murine HSP105 (NIH3T3-HSP105). The NIH3T3-HSP105 cells acquired resistance to apoptosis induced by heat shock or doxorubicin. The small interfering RNA (siRNA)-mediated suppression of HSP105 protein expression induced apoptosis in human cancer cells but not in fibroblasts. By a combination of siRNA introduction and doxorubicin or heat shock treatment, apoptosis was induced synergistically in a human colon cancer cell line, HCT116. In vivo, siRNA inoculation into the human gastric cancer cell line KATO-3 established in the flank of an NOD SCID mouse suppressed the tumor growth. This siRNA-induced apoptosis was mediated through caspases, but not the p53 tumor suppressor protein, even though the HSP105 protein was bound to wild-type p53 protein in HCT116 cells. These findings suggest that the constitutive overexpression of HSP105 in cancer cells is involved in malignant transformation by protecting tumor cells from apoptosis. HSP105 may thus be a novel target molecule for cancer therapy and a treatment regimen using synthetic siRNA to suppress the expression of HSP105 protein may provide a new strategy for cancer therapy.

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.

Radiofrequency radiation does not induce stress response in human T-lymphocytes and rat primary astrocytes

Heat shock proteins (HSPs) are rapidly induced by a variety of stressors, including heat shock, ethanol, heavy metals, UV, and gamma-radiation. Mitogen-activated protein kinases (MAPKs) are also involved in the stress transduction pathways in all eukaryotes. In this study, we attempted to determine whether radiofrequency (RF) radiation is able to induce a non-thermal stress response. Human T-lymphocyte Jurkat cells and rat primary astrocytes were exposed to 1763 MHz of RF radiation at an average specific absorption rate (SAR) of either 2 W/kg or 20 W/kg, for 30 min or 1 h. Temperature was completely controlled at 37 +/- 0.2 degrees C throughout the exposure period. The sham exposures were performed under exactly identical experimental conditions without exposure to RF radiation. We assessed alterations in the expression of HSPs and the activation of MAPKs in the RF-exposed cells. No detectable difference was observed in the expression levels of HSP90, HSP70, and HSP27. The phosphorylation status of MAPKs, extracellular signal-regulated kinases (ERK1/2), c-Jun N-terminal protein kinases (JNK1/2), or p38, did not change significantly. In order to determine whether RF radiation can promote the effects of 12-O-tetradecanoylphorbol 13-acetate (TPA) on stress response, cells were exposed to RF radiation coupled with TPA treatment. When TPA alone was applied, the MAPKs were found to be phosphorylated in a dose-dependent manner. However, RF radiation did not result in any enhancement of TPA-induced MAPK phosphorylation. Neither TPA nor RF radiation exerted any detectable effect on the induction of HSPs. These results indicate that 1763 MHz RF radiation alone did not elicit any stress response, nor did it have any effect on TPA-induced MAPK phosphorylation, under our experimental conditions.

Immunohistochemical detection of the inducible heat shock protein hsp70: a methodological study

Stress-inducible Hsp70i and constitutively expressed Hsc70 are highly related heat shock proteins. Aberrant expression levels and intracellular localization of these proteins has been suggested as a potential marker in certain tumors. The aim of our study was to work out a reliable, immunohistochemical detection of the stress-inducible Hsp70i protein and enabling discrimination between Hsp70i and Hsc70 proteins in paraffin-embedded human tissues. We tested the effect of several fixative procedures and antigen retrieval on the effectiveness of the Hsp70i detection in murine cells cultured in vitro and in liver of rats subjected to heat shock. For cells grown in vitro, specific Hsp70i immunoreactivity was obtained with all fixatives used. However, samples fixed in 10% formalin and 4% paraformaldehyde required antigen retrieval. In liver tissue embedded in paraffin, regardless the fixative used, positive Hsp70i staining could be visible only if antigen retrieval was applied. We applied this procedure for detection of Hsp70i in routine sections of breast and lung cancers fixed with 10% formalin and found that the application of thermal antigen retrieval significantly enhanced the SPA810 immunoreactivity and reduced background staining. This procedure enabled also the differential detection of Hsp70i and Hsc70 in routine histopathological preparations.

Heat shock proteins expression in canine intracutaneous cornifying epithelioma and squamous cell carcinoma

Heat shock proteins (HSPs) are strongly implicated in the control of cell growth, differentiation and biological behaviour of many human cutaneous neoplasms. To our knowledge, no data have been published in the veterinary literature concerning either normal or neoplastic skin. In this study, the immunohistochemical expression of Hsp27, Hsp72 and Hsp73 was evaluated in normal canine skin, 14 intracutaneous cornifying epitheliomas (ICE), 10 well-differentiated and 5 moderately differentiated squamous cell carcinomas (SCC). Expression was correlated with the histological degree of keratinocyte differentiation and proliferation, and investigated as to its usefulness in the differential diagnosis of these canine tumours. In normal epidermis, Hsp27 exhibited cytoplasmic labelling in the spinous and granular layers, whereas in neoplastic tissues it was detected particularly in those areas showing squamous differentiation. Hsp72 immunoreactivity was more intense in ICE and well-differentiated SCC than in normal skin; however, reduced immunolabelling was observed in moderately differentiated SCC. Unlike Hsp72, Hsp73 showed less intense labelling in ICE and well-differentiated SCC than in normal epithelium and an increased positivity in moderately differentiated SCC. These results indicate that HSP immunoreactivity differs between normal and neoplastic canine skin. Hsp27 expression seems to correlate directly with cellular differentiation; by contrast, the involvement of Hsp72/73 in proliferation and differentiation of tumour cells remains controversial. The pattern and intensity of immunolabelling of each investigated HSP did not show, however, significant differences between ICE and SCC; therefore, they do not seem to be useful in the differential diagnosis of these two canine tumours.

Hypoxia and anemia: factors in decreased sensitivity to radiation therapy and chemotherapy?

Hypoxia is a common feature of solid tumors that occurs across a wide variety of malignancies. Hypoxia and anemia (which contributes to tumor hypoxia) can lead to ionizing radiation and chemotherapy resistance by depriving tumor cells of the oxygen essential for the cytotoxic activities of these agents. Hypoxia may also reduce tumor sensitivity to radiation therapy and chemotherapy through one or more indirect mechanisms that include proteomic and genomic changes. These effects, in turn, can lead to increased invasiveness and metastatic potential, loss of apoptosis, and chaotic angiogenesis, thereby further increasing treatment resistance. Investigations of the prognostic significance of pretreatment tumor oxygenation status have shown that hypoxia (oxygen tension [pO(2)] value < or =10 mmHg) is associated with lower overall and disease-free survival, greater recurrence, and less locoregional control in head and neck carcinoma, cervical carcinoma, and soft-tissue sarcoma. In view of the deleterious effect of hypoxia on standard cancer treatment, a variety of hypoxia- and anemia-targeted therapies have been studied in an effort to improve therapeutic effectiveness and patient outcomes. Early evidence from experimental and clinical studies suggests the administration of recombinant human erythropoietin (rHuEPO) may enhance the effectiveness of radiation therapy and chemotherapy by increasing hemoglobin levels and ameliorating anemia in patients with disease- or treatment-related anemia. However, further research is needed in the area of hypoxia-related treatment resistance and its reversal.