Heat shock proteins in oncology: diagnostic biomarkers or therapeutic targets?

Pleiotropic role of HSF1 in neoplastic transformation

HSF1 (Heat Shock transcription Factor 1) is the main transcription factor activated in response to proteotoxic stress. Once activated, it induces an expression of heat shock proteins (HSPs) which enables cells to survive in suboptimal conditions. HSF1 could be also activated by altered kinase signaling characteristic for cancer cells, which is a probable reason for its high activity found in a broad range of tumors. There is rapidly growing evidence that HSF1 supports tumor initiation and growth, as well as metastasis and angiogenesis. It also modulates the sensitivity of cancer cells to therapy. Functions of HSF1 in cancer are connected with HSPs’ activity, which generally protects cells from apoptosis, but also are independent of its classical targets. HSF1-dependent regulation of non-HSPs genes plays a role in cell cycle progression, glucose metabolism, autophagy and drug efflux. HSF1 affects the key cell-survival and regulatory pathways, including p53, RAS/MAPK, cAMP/PKA, mTOR and insulin signaling. Although the exact mechanism of HSF1 action is still somewhat obscure, HSF1 is becoming an attractive target in anticancer therapies, whose inhibition could enhance the effects of other treatments.

Identification of a ternary protein-complex as a therapeutic target for K-Ras-dependent colon cancer

A cancer phenotype is driven by several proteins and targeting a cluster of functionally interdependent molecules should be more effective for therapeutic intervention. This is specifically important for Ras-dependent cancer, as mutated (MT) Ras is non-druggable and targeting its interaction with effectors may be essential for therapeutic intervention. Here, we report that a protein-complex activated by the Ras effector p38γ MAPK is a novel therapeutic target for K-Ras-dependent colon cancer. Unbiased proteomic screening and immune-precipitation analyses identified p38γ interaction with heat shock protein 90 (Hsp90) and K-Ras in K-Ras MT, but not wild-type (WT), colon cancer cells, indicating a role of this complex in Ras-dependent growth. Further experiments showed that this complex requires p38γ and Hsp90 activity to maintain MT, but not WT, K-Ras protein expression. Additional studies demonstrated that this complex is activated by p38γ-induced Hsp90 phosphorylation at S595, which is important for MT K-Ras stability and for K-Ras dependent growth. Of most important, pharmacologically inhibition of Hsp90 or p38γ activity disrupts the complex, decreases K-Ras expression, and selectively inhibits the growth of K-Ras MT colon cancer in vitro and in vivo. These results demonstrated that the p38γ-activated ternary complex is a novel therapeutic target for K-Ras-dependent colon cancer.

Tumour suppressor HLJ1: A potential diagnostic, preventive and therapeutic target in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality throughout the world. Non-small cell lung cancer (NSCLC) accounts for 85% of all diagnosed lung cancers. Despite considerable progress in the diagnosis and treatment of the disease, the overall 5-year survival rate of NSCLC patients remains lower than 15%. The most common causes of death in lung cancer patients are treatment failure and metastasis. Therefore, developing novel strategies that target both tumour growth and metastasis is an important and urgent mission for the next generation of anticancer therapy research. Heat shock proteins (HSPs), which are involved in the fundamental defence mechanism for maintaining cellular viability, are markedly activated during environmental or pathogenic stress. HSPs facilitate rapid cell division, metastasis, and the evasion of apoptosis in cancer development. These proteins are essential players in the development of cancer and are prime therapeutic targets. In this review, we focus on the current understanding of the molecular mechanisms responsible for HLJ1’s role in lung cancer carcinogenesis and progression. HLJ1, a member of the human HSP 40 family, has been characterised as a tumour suppressor. Research studies have also reported that HLJ1 shows promising dual anticancer effects, inhibiting both tumour growth and metastasis in NSCLC. The accumulated evidence suggests that HLJ1 is a potential biomarker and treatment target for NSCLC.

Mortalin (GRP75/HSPA9) upregulation promotes survival and proliferation of medullary thyroid carcinoma cells

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor mainly caused by mutations in the rearranged during transfection (RET) proto-oncogene. For therapy of advanced MTC, the Food and Drug Administration recently approved vandetanib and cabozantinib, the tyrosine kinase inhibitors targeting RET, vascular endothelial growth factor receptor, epidermal growth factor receptor and/or c-MET. Nevertheless, not all patients respond to these drugs, demanding additional therapeutic strategies. We found that mortalin (HSPA9/GRP75), a member of HSP70 family, is upregulated in human MTC tissues and that its depletion robustly induces cell death and growth arrest in MTC cell lines in culture and in mouse xenografts. These effects were accompanied by substantial downregulation of RET, induction of the tumor-suppressor TP53 and altered expression of cell cycle regulatory machinery and apoptosis markers, including E2F-1, p21(CIP1), p27(KIP1) and Bcl-2 family proteins. Our investigation of the molecular mechanisms underlying these effects revealed that mortalin depletion induces transient MEK/ERK (extracellular signal-regulated kinase) activation and altered mitochondrial bioenergetics in MTC cells, as indicated by depolarized mitochondrial membrane, decreased oxygen consumption and extracellular acidification and increased oxidative stress. Intriguingly, mortalin depletion induced growth arrest partly via the MEK/ERK pathway, whereas it induced cell death by causing mitochondrial dysfunction in a Bcl-2-dependent manner. However, TP53 was not necessary for these effects except for p21(CIP1) induction. Moreover, mortalin depletion downregulated RET expression independently of MEK/ERK and TP53. These data demonstrate that mortalin is a key regulator of multiple signaling and metabolic pathways pivotal to MTC cell survival and proliferation, proposing mortalin as a novel therapeutic target for MTC.

Biomarkers to evaluate the effects of temperature and methanol on recombinant Pichia pastoris

Pichia pastoris is methylotrophic yeast used as an efficient expression system for heterologous protein production. In order to evaluate the effects of temperature (10 and 30 °C) and methanol (1 and 3% (v/v)) on genetically-modified Pichia pastoris, different biomarkers were evaluated: Heat stress (HSF-1 and Hsp70), oxidative stress (OGG1 and TBARS) and antioxidant (GLR). Three yeast cultures were performed: 3X = 3% methanol-10 °C, 4X = 3% methanol-30 °C, and 5X = 1% methanol-10°C. The expression level of HIF-1α, HSF-1, HSP-70 and HSP-90 biomarkers were measured by Western blot and in situ detection was performed by immunocytochemistry. Ours results show that at 3% methanol −30 °C there is an increase of mitochondrial OGG1 (mtOGG1), Glutathione Reductase (GLR) and TBARS. In addition, there was a cytosolic expression of HSF-1 and HSP-70, which indicates a deprotection against nucleolar fragmentation (apoptosis). On the other hand, at 3% methanol −10 °C and 1% and at methanol −10 °C conditions there was nuclear expression of OGG1, lower levels of TBARS and lower expression of GLR, cytosolic expression of HSF-1 and nuclear expression HSP-70. In conclusion, our results suggest that 3% methanol-30 °C is a condition that induces a strong oxidative stress and risk factors of apoptosis in modified-genetically P. pastoris.

Profiling Hsp90 differential expression and the molecular effects of the Hsp90 inhibitor IPI-504 in high-grade glioma models

Retaspimycin hydrochloride (IPI-504), an Hsp90 (heat shock protein 90) inhibitor, has shown activity in multiple preclinical cancer models, such as lung, breast and ovarian cancers. However, its biological effects in gliomas and normal brain derived cellular populations remain unknown. In this study, we profiled the expression pattern of Hsp90α/β mRNA in stable glioma cell lines, multiple glioma-derived primary cultures and human neural stem/progenitor cells. The effects of IPI-504 on cell proliferation, apoptosis, motility and expression of Hsp90 client proteins were evaluated in glioma cell lines. In vivo activity of IPI-504 was investigated in subcutaneous glioma xenografts. Our results showed Hsp90α and Hsp90β expression levels to be patient-specific, higher in high-grade glioma-derived primary cells than in low-grade glioma-derived primary cells, and strongly correlated with CD133 expression and differentiation status of cells. Hsp90 inhibition by IPI-504 induced apoptosis, blocked migration and invasion, and significantly decreased epidermal growth factor receptor levels, mitogen-activated protein kinase and/or Akt activities, and secretion of vascular endothelial growth factor in glioma cell lines. In vivo study showed that IPI-504 could mildly attenuate tumor growth in immunocompromised mice. These findings suggest that targeting Hsp90 by IPI-504 has the potential to become an active therapeutic strategy in gliomas in a selective group of patients, but further research into combination therapies is still needed.

Heat shock protein 70 gene polymorphisms and cancer risk: a meta-analysis

The polymorphisms in the three main heat shock protein 70 (HSP70-1, HSP70-2, and HSP70-hom) genes were identified to be associated with cancer risk. However, the results are inconsistent. We perform a meta-analysis to evaluate the association between the three HSP70 polymorphisms and cancer risk. Relevant studies were identified using PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases up to March 29, 2014. The cancer risk associated with the HSP70 polymorphisms was estimated for each study by odds ratios (OR) together with its 95% confidence interval (CI), respectively. Twenty case-control studies from eighteen publications were included; a significant association was observed for HSP70-2 polymorphism (dominant model: OR = 1.53, 95% CI: 1.11–2.09; recessive model: OR = 1.91, 95% CI: 1.06–3.45; AG versus AA: OR = 1.38, 95% CI: 1.03–1.84; GG versus AA: OR = 2.34, 95% CI: 1.21–4.54), while there was no significant association for HSP70-1 and HSP70-hom polymorphisms. Besides, in stratification analyses by ethnicity, cancer type, and source of control, significant association was detected for HSP70-2 polymorphism, while for HSP70-hom polymorphism, we found a significant association in hospital-based population under homozygote comparison model. This meta-analysis suggests that the HSP70-2 polymorphism rather than HSP70-hom and HSP70-1 polymorphisms was associated with the risk of cancer.

Prognostic implication of HSPA (HSP70) in breast cancer patients treated with neoadjuvant anthracycline-based chemotherapy

Neoadjuvant chemotherapy is used in patients with locally advanced breast cancer to reduce tumor size before surgery. Unfortunately, resistance to chemotherapy may arise from a variety of mechanisms. Heat shock proteins (HSPs), which are highly expressed in mammary tumor cells, have been implicated in anticancer drug resistance. In spite of the widely described value of HSPs as molecular markers in cancer, their implications in breast tumors treated with anthracycline-based neoadjuvant chemotherapy has been poorly explored. In this study, we have evaluated, by immunohistochemistry, the expression of HSP27 (HSPB1) and HSP70 (HSPA) in serial biopsies from locally advanced breast cancer patients (n = 60) treated with doxorubicin (DOX)- or epirubicin (EPI)-based monochemotherapy. Serial biopsies were taken at days 1, 3, 7, and 21, and compared with prechemotherapy and surgical biopsies. After surgery, the patients received additional chemotherapy with cyclophosphamide, methotrexate, and 5-fluorouracil. High nuclear HSPB1 and HSPA expressions were found in invasive cells after DOX/EPI administration (P < 0.001), but the drug did not affect the cytoplasmic expression of the HSPs. Infiltrating lymphocytes showed high nuclear HSPA (P < 0.01) levels at postchemotherapy. No correlations were found between HSPs expression and the clinical and pathological response to neoadjuvant therapy. However, in postchemotherapy biopsies, high nuclear (>31 % of the cells) and cytoplasmic HSPA expressions (>11 % of the tumor cells) were associated with better DFS (P = 0.0348 and P = 0.0118, respectively). We conclude that HSPA expression may be a useful prognostic marker in breast cancer patients treated with neoadjuvant DOX/EPI chemotherapy indicating the need to change the administered drugs after surgery for overcoming drug resistance.

High level of HSF1 associates with aggressive endometrial carcinoma and suggests potential for HSP90 inhibitors

Background:

Recent identification of a specific role of HSF1 in cancer progression has led to new relevance of HSF1 as both a prognostic and a predictive marker. The role of HSF1 in endometrial cancer has so far been unexplored.

Methods:

A total of 823 lesions from endometrial carcinoma precursors, primary tumours and metastases were prospectively collected and explored for HSF1 protein expression in relation to established markers for aggressive disease and survival. Transcriptional alterations related to HSF1 protein level were investigated by microarray analysis for 224 freshly frozen samples in parallel.

Results:

High expression of HSF1 protein in endometrial carcinoma is significantly associated with aggressive disease and poor survival (all P-values ⩽0.02), also among ERα-positive patients presumed to have good prognosis. The HSF1-related gene signatures increase during disease progression and were also found to have prognostic value. Gene expression analyses identified HSP90 inhibition as a potential novel therapeutic approach for cases with high protein expression of HSF1.

Conclusions:

We demonstrate for the first time in endometrial cancer that high expression of HSF1 and measures for transcriptional activation of HSF1 associate with poor outcome and disease progression. The HSP90 inhibitors are suggested as new targeted therapeutics for patients with high HSF1 levels in tumour in particular.

Family with sequence similarity 107: A family of stress responsive small proteins with diverse functions in cancer and the nervous system (Review)

Under conditions of acute stress, rapid adaptation is crucial for maximizing biological survival. The responses to environmental stress are often complex, involving numerous genes and integrating events at the cellular and organismal levels. The heat shock proteins (HSPs) are a family of highly conserved proteins that play critical roles in maintaining cell homeostasis and protecting cells under chronic and acute stress conditions. The genes for these stress-responding proteins are widely distributed in organisms, tissues and cells. HSPs participate in a variety of physiological processes and are associated with various types of disease. In this review, we focused on family with sequence similarity 107 (FAM107), a novel unique protein family that exhibits functional similarity with HSPs during the cellular stress response. This review aimed to summarize the biological properties of FAM107 in cancer and the nervous system.

Pancreatic cancer diagnosis by free and exosomal miRNA

Patients with pancreatic adenocarcinoma (PaCa) have a dismal prognosis. This is in part due to late diagnosis prohibiting surgical intervention, which provides the only curative option as PaCa are mostly chemo- and radiation resistance. Hope is raised on a reliable non-invasive/minimally invasive diagnosis that is still missing. Recently two diagnostic options are discussed, serum MicroRNA (miRNA) and serum exosomes. Serum miRNA can be free or vesicle-, particularly, exosomes-enclosed. This review will provide an overview on the current state of the diagnostic trials on free serum miRNA and proceed with an introduction of exosomes that use as a diagnostic tool in serum and other body fluids has not received sufficient attention, although serum exosome miRNA in combination with protein marker expression likely will increase the diagnostic and prognostic power. By their crosstalk with host cells, which includes binding-initiated signal transduction, as well as reprogramming target cells via the transfer of proteins, mRNA and miRNA exosomes are suggested to become a most powerful therapeutics. I will discuss which hurdles have still to be taken as well as the different modalities, which can be envisaged to make therapeutic use of exosomes. PaCa are known to most intensely crosstalk with the host as apparent by desmoplasia and frequent paraneoplastic syndromes. Thus, there is hope that the therapeutic application of exosomes brings about a major breakthrough.

Inhibition of Raf-MEK-ERK and hypoxia pathways by Phyllanthus prevents metastasis in human lung (A549) cancer cell line

BACKGROUND

Lung cancer constitutes one of the malignancies with the greatest incidence and mortality rates with 1.6 million new cases and 1.4 million deaths each year. Prognosis remains poor due to deleterious development of multidrug resistance resulting in less than 15% lung cancer patients reaching five years survival. We have previously shown that Phyllanthus induced apoptosis in conjunction with its antimetastastic action. In the current study, we aimed to determine the signaling pathways utilized by Phyllanthus to exert its antimetastatic activities.

METHODS

Cancer 10-pathway reporter array was performed to screen the pathways affected by Phyllanthus in lung carcinoma cell line (A549) to exert its antimetastatic effects. Results from this array were then confirmed with western blotting, cell cycle analysis, zymography technique, and cell based ELISA assay for human total iNOS. Two-dimensional gel electrophoresis was subsequently carried out to study the differential protein expressions in A549 after treatment with Phyllanthus.

RESULTS

Phyllanthus was observed to cause antimetastatic activities by inhibiting ERK1/2 pathway via suppression of Raf protein. Inhibition of this pathway resulted in the suppression of MMP2, MMP7, and MMP9 expression to stop A549 metastasis. Phyllanthus also inhibits hypoxia pathway via inhibition of HIF-1α that led to reduced VEGF and iNOS expressions. Proteomic analysis revealed a number of proteins downregulated by Phyllanthus that were involved in metastatic processes, including invasion and mobility proteins (cytoskeletal proteins), transcriptional proteins (proliferating cell nuclear antigen; zinc finger protein), antiapoptotic protein (Bcl2) and various glycolytic enzymes. Among the four Phyllanthus species tested, P. urinaria showed the greatest antimetastatic activity.

CONCLUSIONS

Phyllanthus inhibits A549 metastasis by suppressing ERK1/2 and hypoxia pathways that led to suppression of various critical proteins for A549 invasion and migration.

Heat shock protein 27: a potential biomarker of peritoneal metastasis in epithelial ovarian cancer?

Ovarian cancer is the major gynaecologic malignancy and the leading cause of death in gynaecological cancer. Heat shock proteins (HSPs) are highly expressed in many malignant cancers and involved in metastasis including ovarian cancer. The early detection of peritoneal metastases in epithelial ovarian cancer may be more important in clinical care. HSP27, a small heat shock protein, is correlated with peritoneal metastases in epithelial ovarian cancer tissues. In this study, we investigated whether the levels of total HSP27 were detectable in serum and whether it could be a predictive biomarker for peritoneal metastases in epithelial ovarian cancer. Serum samples from 48 patients with epithelial ovarian cancer, 35 patients with benign ovarian tumours and 24 healthy women were included in this study. The serum levels of total HSP27 were measured by enzyme-linked immunosorbent assay (ELISA). There was no difference in the serum levels of total HSP27 between women with benign ovarian tumours and healthy women. However, the serum levels of total HSP27 were significantly increased in patients with epithelial ovarian cancer. The increased serum levels of total HSP27 were only seen in patients with peritoneal metastases. Furthermore, increased serum levels of total HSP27 were significantly reduced after the combination chemotherapies in patients with peritoneal metastases. These data suggest that circulating HSP27 levels were increased in epithelial ovarian cancer and correlated with peritoneal metastases. The measurement of serum HSP27 levels may be used as a potential additional indicator for peritoneal metastases in epithelial ovarian cancer and response to treatment.

Radiosensitizers in pancreatic cancer--preclinical and clinical exploits with molecularly targeted agents

There has been an explosion in the number of molecularly targeted agents engineered to inhibit specific molecular pathways driving the tumorigenic phenotype in cancer cells. Some of these molecularly targeted agents have demonstrated robust clinical effects, but few result in meaningful durable responses. Therapeutic radiation is used to treat a majority of cancer patients with recent technologic and pharmacologic enhancements, leading to improvements in the therapeutic ratio for cancer care. Radiotherapy has a very specific role in select cases of postoperative and locally advanced pancreatic cancer patients, but control of metastatic disease still appears to be the major limiting factor behind improvements in cure. Recent rapid autopsy pathologic findings suggest a sub-group of advanced pancreatic cancer patients where death is caused from local disease progression and who would thus benefit from improved local control. One promising approach is to combine molecularly targeted agents with radiotherapy to improve tumor response rates and likelihood of durable local control. We review suggested recommendations on the investigation of molecularly targeted agents as radiosensitizers from preclinical studies to implementation in phase I–II clinical trials. We then discuss a select set of molecularly targeted therapies that we believe show promise as radiosensitizers in the treatment of pancreatic cancer.

Geldanamycin-induced osteosarcoma cell death is associated with hyperacetylation and loss of mitochondrial pool of heat shock protein 60 (hsp60)

Osteosarcoma is one of the most malignant tumors of childhood and adolescence that is often resistant to standard chemo- and radio-therapy. Geldanamycin and geldanamycin analogs have been recently studied as potential anticancer agents for osteosarcoma treatment. Here, for the first time, we have presented novel anticancer mechanisms of geldanamycin biological activity. Moreover, we demonstrated an association between the effects of geldanamycin on the major heat shock proteins (HSPs) and the overall survival of highly metastatic human osteosarcoma 143B cells. We demonstrated that the treatment of 143B cells with geldanamycin caused a subsequent upregulation of cytoplasmic Hsp90 and Hsp70 whose activity is at least partly responsible for cancer development and drug resistance. On the other hand, geldanamycin induced upregulation of Hsp60 gene expression, and a simultaneous loss of hyperacetylated Hsp60 mitochondrial protein pool resulting in decreased viability and augmented cancer cell death. Hyperacetylation of Hsp60 seems to be associated with anticancer activity of geldanamycin. In light of the fact that mitochondrial dysfunction plays a critical role in the apoptotic signaling pathway, the presented data may support a hypothesis that Hsp60 can be another functional part of mitochondria-related acetylome being a potential target for developing novel anticancer strategies.

A mortalin/HSPA9-mediated switch in tumor-suppressive signaling of Raf/MEK/extracellular signal-regulated kinase

Dysregulated Raf/MEK/extracellular signal-regulated kinase (ERK) signaling, a common hallmark of tumorigenesis, can trigger innate tumor-suppressive mechanisms, which must be inactivated for carcinogenesis to occur. This innate tumor-suppressive signaling may provide a potential therapeutic target. Here we report that mortalin (HSPA9/GRP75/PBP74) is a novel negative regulator of Raf/MEK/ERK and may provide a target for the reactivation of tumor-suppressive signaling of the pathway in cancer. We found that mortalin is present in the MEK1/MEK2 proteome and is upregulated in human melanoma biopsy specimens. In different MEK/ERK-activated cancer cell lines, mortalin depletion induced cell death and growth arrest, which was accompanied by increased p21(CIP1) transcription and MEK/ERK activity. Remarkably, MEK/ERK activity was necessary for mortalin depletion to induce p21(CIP1) expression in B-Raf(V600E)-transformed cancer cells regardless of their p53 status. In contrast, in cell types exhibiting normal MEK/ERK status, mortalin overexpression suppressed B-Raf(V600E)- or ΔRaf-1:ER-induced MEK/ERK activation, p21(CIP1) expression, and cell cycle arrest. Other HSP70 family chaperones could not effectively replace mortalin for p21(CIP1) regulation, suggesting a unique role for mortalin. These findings reveal a novel mechanism underlying p21(CIP1) regulation in MEK/ERK-activated cancer and identify mortalin as a molecular switch that mediates the tumor-suppressive versus oncogenic result of dysregulated Raf/MEK/ERK signaling. Our study also demonstrates that p21(CIP1) has dual effects under mortalin-depleted conditions, i.e., mediating cell cycle arrest while limiting cell death.

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.

HSP70 inhibition by 2-phenylethynesulfonamide induces lysosomal cathepsin D release and immunogenic cell death in primary effusion lymphoma

Heat-shock protein (HSP) 70 is aberrantly expressed in different malignancies and has a cancer-specific cell-protective effect. As such, it has emerged as a promising target for anticancer therapy. In this study, the effect of the HSP70-specific inhibitor (PES), also Pifitrin-μ, on primary effusion lymphoma (PEL) cell viability was analyzed. PES treatment induced a dose- and time-dependent cytotoxic effect in BC3 and BCBL1 PEL cells by inducing lysosome membrane permeabilization, relocation of cathepsin D in the cytosol, Bid cleavage, mitochondrial depolarization with release and nuclear translocation of apoptosis-activating factor. The PES-induced cell death in PEL cells was characterized by the appearance of Annexin-V/propidium iodide double-positive cells from the early times of treatment, indicating the occurrence of an additional type of cell death other than apoptosis, which, accordingly, was not efficiently prevented by the pan-caspase inhibitor Z-VAD-fmk. Conversely, PES-induced cell death was robustly reduced by pepstatin A, which inhibits Bid and caspase 8 processing. In addition, PES was responsible for a block of the autophagic process in PEL cells. Finally, we found that PES-induced cell death has immunogenic potential being able to induce dendritic cell activation.

A specific expression profile of heat-shock proteins and glucose-regulated proteins is associated with response to neoadjuvant chemotherapy in oesophageal adenocarcinomas

Background:

Oesophageal adenocarcinomas often show resistances to chemotherapy (CTX), therefore, it would be of high interest to better understand the mechanisms of resistance. We examined the expression of heat-shock proteins (HSPs) and glucose-regulated proteins (GRPs) in pretherapeutic biopsies of oesophageal adenocarcinomas to assess their potential role in CTX response.

Methods:

Ninety biopsies of locally advanced adenocarcinomas before platin/5-fluorouracil (FU)-based CTX were investigated by reverse phase protein arrays (RPPAs), immunohistochemistry (IHC) and quantitative RT–PCR.

Results:

CTX response strongly correlated with survival (P=0.001). Two groups of tumours with specific protein expression patterns were identified by RPPA: Group A was characterised by low expression of HSP90, HSP27 and p-HSP27^{(Ser15, Ser78, Ser82)} and high expression of GRP78, GRP94, HSP70 and HSP60; Group B exhibited the inverse pattern. Tumours of Group A were more likely to respond to CTX, resulting in histopathological tumour regression (P=0.041) and post-therapeutic down-categorisation from cT3 to ypT0–T2 (P=0.040). High HSP60 protein (IHC) and mRNA expression were also associated with tumour down-categorisation (P=0.016 and P=0.004).

Conclusion:

Our findings may enhance the understanding of CTX response mechanisms, might be helpful to predict CTX response and might have translational relevance as they highlight the role of potentially targetable cellular stress proteins in the context of CTX response.

A natural-like synthetic small molecule impairs bcr-abl signaling cascades and induces megakaryocyte differentiation in erythroleukemia cells

Over the past years, we synthesized a series of new molecules that are hybrids of spirocyclic ketones as complexity-bearing cores with bi- and ter-phenyls as privileged fragments. Some of these newly-shaped small molecules showed antiproliferative, pro-apoptotic and differentiating activity in leukemia cell lines. In the present study, to investigate more in depth the mechanisms of action of these molecules, the protein expression profiles of K562 cells treated with or without the compounds IND_S1, MEL_T1, IND_S7 and MEL_S3 were analyzed using two-dimensional gel electrophoresis coupled with mass spectrometry. Proteome comparisons revealed several differentially expressed proteins, mainly related to cellular metabolism, chaperone activity, cytoskeletal organization and RNA biogenesis. The major results were validated by Western blot and qPCR. To attempt integrating findings into a cellular signaling context, proteomic data were explored using MetaCore. Network analysis highlighted relevant relationships between the identified proteins and additional potential effectors. Notably, qPCR validation of central hubs showed that the compound MEL_S3 induced high mRNA levels of the transcriptional factors EGR1 and HNF4-alpha; the latter to our knowledge is reported here for the first time to be present in K562 cells. Consistently with the known EGR1 involvement in the regulation of differentiation along megakaryocyte lineage, MEL_S3-treated leukemia cells showed a marked expression of glycoprotein IIb/IIIa (CD41) and glycoprotein Ib (CD42), two important cell markers in megakaryocytic differentiation, together with morphological aspects of megakaryoblasts and megakaryocytes.

In silico analysis of molecular mechanisms of legume lectin-induced apoptosis in cancer cells

OBJECTIVES

The legume lectin family, one of the most extensively studied plant lectin families, has received increasing attention for the remarkable anti-tumor activities of its members for binding specific cancer cell surface glycoconjugates. MicroRNAs, a class of small, non-coding RNAs, control translation and stability of mRNAs at post-transcriptional and translational levels. To date, accumulating evidence has revealed that microRNAs are involved in progression of a number of human diseases, especially cancers. However, the molecular manners of microRNA-modulated apoptosis in legume lectin-treated cancer cells are still under investigation.

MATERIALS AND METHODS

We performed in silico analyses to study the interactions between three typical legume lectins (ConA, SFL and SAL) and some specific sugar-containing receptors (for example, EGFR, TNFR1, HSP70 and HSP90). Additionally, we predicted some relevant microRNAs which could significantly regulate these aforementioned targetreceptors and thus inhibiting down-stream cancer-related signaling pathways.

RESULTS

The results showed that these three legume lectins could competitively bind sugar-containing receptors such as EGFR, TNFR1, HSP70 and HSP90 in two ways, via anti-apoptotic or survival pathways. On the one hand, the legume lectins could induce cancer cell death through triggering receptor-mediated signaling pathways, which resulted from indirect binding between legume lectins and mannoses resided in receptors. On the other hand, direct binding between legume lectins and receptors could lead to steric hindrance, which would disturb efficient interactions between them, and thus, the legume lectins would induce cancer cell death by triggering receptor-mediated signaling pathways. In addition, we identified several relevant microRNAs that regulated these targeted receptors, thereby ultimately causing cancer cell apoptosis.

CONCLUSIONS

These findings provide new perspectives for exploring microRNA-modulated cell death in legume lectin-treated cancer cells, which could be utilized in combination therapy for future cancer drug development.

Comparison of the expression of 5 heat shock proteins in benign and malignant salivary gland tumor tissues

The objective of this study was to analyze the significance and potential value of heat shock proteins (HSPs) in salivary gland tumors. We found that expression of HSP60, HSP70, HSP86 and HSP84 were all upregulated in both salivary gland benign tumors and malignant tumors, and that the expression of HSP70, HSP86 and HSP84 was more greatly overexpressed in the malignant tumors (each P<0.01). For HSP27, expression was upregulated both in malignant and benign tumors, with less expression observed in malignant tumors (P<0.01). In malignant tumors, expression of HSP27 was negatively correlated with the age of the patients, size of the tumor tissue, occurrence of neural invasion and metastasis (each P<0.05). Additionally, in malignant tumors, HSP70 and HSP86 were both positively correlated with occurrence site, neural invasion and metastasis (each P<0.05), while HSP60 was only negatively correlated with the age of the patients (P<0.05). HSP86 was also positively correlated with malignant degree (P<0.01). In malignant tumors, the proliferation index (PI), which was marked by proliferating cell nuclear antigen (PCNA; PCNA-PI) was 49.95±14.569, which was significantly higher compared with that in benign tumors (P<0.001), which was in accordance with the upregulation of HSP70, HSP86 or HSP84; however, an adverse correlation was found between HSP27 expression and PCNA (each P<0.05). In conclusion, these results suggest that HSPs are involved in the occurrence and development of salivary gland tumors. HSP70, HSP86 and HSP84 retained the higher multiplication capability of the malignant tumor cells, however, HSP27 did not. Thus, the upregulation of HSP70, HSP86 and HSP84 and the downregulation of HSP27 may all be used as biomarkers of the occurrence and development of malignant salivary gland tumors. Moreover, the extremely high expression of HSP86 and HSP84 in benign tumors indicates the malignant transformation potential.

Glioma pathogenesis-related protein 1 induces prostate cancer cell death through Hsc70-mediated suppression of AURKA and TPX2

In this study we report that expression of glioma pathogenesis-related protein 1 (GLIPR1) regulated numerous apoptotic, cell cycle, and spindle/centrosome assembly-related genes, including AURKA and TPX2, and induced apoptosis and/or mitotic catastrophe (MC) in prostate cancer (PCa) cells, including p53-mutated/deleted, androgen-insensitive metastatic PCa cells. Mechanistically, GLIPR1 interacts with heat shock cognate protein 70 (Hsc70); this interaction is associated with SP1 and c-Myb destabilization and suppression of SP1- and c-Myb-mediated AURKA and TPX2 transcription. Inhibition of AURKA and TPX2 using siRNA mimicked enforced GLIPR1 expression in the induction of apoptosis and MC. Recombinant GLIPR1-ΔTM protein inhibited AURKA and TPX2 expression, induced apoptosis and MC, and suppressed orthotopic xenograft tumor growth. Our results define a novel GLIPR1-regulated signaling pathway that controls apoptosis and/or mitotic catastrophe in PCa cells and establishes the potential of this pathway for targeted therapies.

Tumor-exosomes and leukocyte activation: an ambivalent crosstalk

Background

Tumor-exosomes being reported to suppress or promote a cancer-directed immune response, we used exosomes of the rat pancreatic adenocarcinoma BSp73ASML (ASML) to evaluate, whether and which steps in immune response induction can be affected by tumor-exosomes and how the impaired responsiveness can be circumvented.

Results

ASML-exosomes bind to and are taken up by all leukocyte subpopulations in vivo and in vitro, uptake by CD11b⁺ leukocytes exceeding that by T and B cells. ASML-exosomes affect leukocyte proliferation via reduced CD44v6 up-regulation and lck, ZAP70 and ERK1,2 phosphorylation, which can be compensated by dendritic cells (DC). ASML-exosomes do not support T_reg. Yet, impaired activation of anti-apoptotic signals is accompanied by slightly increased apoptosis susceptibility. IgM secretion is unaffected; NK and CTL activity are strengthened, ASML-exosomes co-operating with DC in CTL activation. ASML-exosomes transiently interfere with leukocyte migration by occupying migration-promoting receptors CD44, CD49d, CD62L and CD54 during binding/internalization.

Conclusion

ASML-exosomes might well serve as adjuvant in immunotherapy as they support leukocyte effector functions and have only a minor impact on leukocyte activation, which can be overridden by DC. However, exosome-induced modulation of immune cells relies, at least in part, on exosome uptake and message transfer. This implies that depending on the individual tumor's exosome composition, exosomes may distinctly affect the immune system. Nonetheless, whether immunotherapy can profit from using tumor-exosomes as adjuvant can easily be settled beforehand in vitro.

Insulin-degrading enzyme (IDE): a novel heat shock-like protein

Insulin-degrading enzyme (IDE) is a highly conserved zinc metallopeptidase that is ubiquitously distributed in human tissues, and particularly abundant in the brain, liver, and muscles. IDE activity has been historically associated with insulin and β-amyloid catabolism. However, over the last decade, several experimental findings have established that IDE is also involved in a wide variety of physiopathological processes, including ubiquitin clearance and Varicella Zoster Virus infection. In this study, we demonstrate that normal and malignant cells exposed to different stresses markedly up-regulate IDE in a heat shock protein (HSP)-like fashion. Additionally, we focused our attention on tumor cells and report that (i) IDE is overexpressed in vivo in tumors of the central nervous system (CNS); (ii) IDE-silencing inhibits neuroblastoma (SHSY5Y) cell proliferation and triggers cell death; (iii) IDE inhibition is accompanied by a decrease of the poly-ubiquitinated protein content and co-immunoprecipitates with proteasome and ubiquitin in SHSY5Y cells. In this work, we propose a novel role for IDE as a heat shock protein with implications in cell growth regulation and cancer progression, thus opening up an intriguing hypothesis of IDE as an anticancer target.

Tissue specific electrochemical fingerprinting

Background

Proteomics and metalloproteomics are rapidly developing interdisciplinary fields providing enormous amounts of data to be classified, evaluated and interpreted. Approaches offered by bioinformatics and also by biostatistical data analysis and treatment are therefore of extreme interest. Numerous methods are now available as commercial or open source tools for data processing and modelling ready to support the analysis of various datasets. The analysis of scientific data remains a big challenge, because each new task sets its specific requirements and constraints that call for the design of a targeted data pre-processing approach.

Methodology/Principal Findings

This study proposes a mathematical approach for evaluating and classifying datasets obtained by electrochemical analysis of metallothionein in rat 9 tissues (brain, heart, kidney, eye, spleen, gonad, blood, liver and femoral muscle). Tissue extracts were heated and then analysed using the differential pulse voltammetry Brdicka reaction. The voltammograms were subsequently processed. Classification models were designed making separate use of two groups of attributes, namely attributes describing local extremes, and derived attributes resulting from the level = 5 wavelet transform.

Conclusions/Significance

On the basis of our results, we were able to construct a decision tree that makes it possible to distinguish among electrochemical analysis data resulting from measurements of all the considered tissues. In other words, we found a way to classify an unknown rat tissue based on electrochemical analysis of the metallothionein in this tissue.

Smurf E3 ubiquitin ligases at the cross roads of oncogenesis and tumor suppression

Smad ubiquitin regulatory factors (Smurfs) belong to the HECT- family of E3 ubiquitin ligases and comprise mainly of two members, Smurf1 and Smurf2. Initially, Smurfs have been implicated in determining the competence of cells to respond to TGF-β/BMP signaling pathway. Nevertheless, the intrinsic catalytic activity has extended the repertoire of Smurf substrates beyond the TGF-β/BMP super family expanding its realm further to epigenetic modifications of histones governing the chromatin landscape. Through regulation of a large number of proteins in multiple cellular compartments, Smurfs regulate diverse cellular processes, including cell-cycle progression, cell proliferation, differentiation, DNA damage response, maintenance of genomic stability, and metastasis. As the genomic ablation of Smurfs leads to global changes in histone modifications and predisposition to a wide spectrum of tumors, Smurfs are also considered to have a novel tumor suppressor function. This review focuses on regulation network and biological functions of Smurfs in connection with its role in cancer progression. By providing a portrait of their protein targets, we intend to link the substrate specificity of Smurfs with their contribution to tumorigenesis. Since the regulation and biological functions of Smurfs are quite complex, understanding the oncogenic potential of these E3 ubiquitin ligases may facilitate the development of mechanism-based drugs in cancer treatment.

Heat stress induces epithelial plasticity and cell migration independent of heat shock factor 1

Current cancer therapies including cytotoxic chemotherapy, radiation and hyperthermic therapy induce acute proteotoxic stress in tumour cells. A major challenge to cancer therapeutic efficacy is the recurrence of therapy-resistant tumours and how to overcome their emergence. The current study examines the concept that tumour cell exposure to acute proteotoxic stress results in the acquisition of a more advanced and aggressive cancer cell phenotype. Specifically, we determined whether heat stress resulted in an epithelial-to-mesenchymal transition (EMT) and/or the enhancement of cell migration, components of an advanced and therapeutically resistant cancer phenotype. We identified that heat stress enhanced cell migration in both the lung A549, and breast MDA-MB-468 human adenocarcinoma cell lines, with A549 cells also undergoing a partial EMT. Moreover, in an in vivo model of thermally ablated liver metastases of the mouse colorectal MoCR cell line, immunohistological analysis of classical EMT markers demonstrated a shift to a more mesenchymal phenotype in the surviving tumour fraction, further demonstrating that thermal stress can induce epithelial plasticity. To identify a mechanism by which thermal stress modulates epithelial plasticity, we examined whether the major transcriptional regulator of the heat shock response, heat shock factor 1 (HSF1), was a required component. Knockdown of HSF1 in the A549 model did not prevent the associated morphological changes or enhanced migratory profile of heat stressed cells. Therefore, this study provides evidence that heat stress significantly impacts upon cancer cell epithelial plasticity and the migratory phenotype independent of HSF1. These findings further our understanding of novel biological downstream effects of heat stress and their potential independence from the classical heat shock pathway.

Hyperthermia reduces migration of osteosarcoma by suppression of autocrine motility factor

Autocrine motility factor (AMF) plays an important role in the development of metastasis by regulating tumor cell motility. The expression of AMF is associated with metastasis in malignant musculoskeletal tumors including osteosarcoma. Recent studies indicated that hyperthermia contributes to the improvement of the prognosis of patients with soft tissue sarcomas; however, few reports have evaluated the impact of hyperthermia on tumor cell motility, which is an important factor of metastasis. The purpose of this study was to evaluate the effect of hyperthermia with or without heat shock protein (HSP) inhibitors on the motility and AMF expression in an osteosarcoma cell line. Hyperthermia was carried out at 41°C for 24 h. According to microarray results, HSP90, HSP70 and HSP27 expression was upregulated in osteosarcoma cells under hyperthermia. The intracellular, secreted AMF, mRNA of AMF and cell motility were evaluated by western blotting, ELISA, RT-PCR, wound healing and phagokinetic track assays, respectively. The protein secretion and mRNA levels of AMF and tumor cell motility were significantly decreased by hyperthermia. Of note, the downregulated AMF expression and motility were recovered by the addition of an HSP27 inhibitor. By contrast, the HSP90 and HSP70/72/105 inhibitors had no effect on AMF expression and motility downregulated by hyperthermia. In conclusion, hyperthermia reduced AMF expression and tumor cell motility via HSP27 and may therefore be applied as osteosarcoma treatment.

DNAJC25 is downregulated in hepatocellular carcinoma and is a novel tumor suppressor gene

HSP40, also known as DnaJ, is one of the subfamilies of the heat shock protein family. DnaJ/Hsp40 proteins act as co-chaperones by binding to the chaperone Hsp70 through their J domain and stimulating ATP hydrolysis to aid protein translation, folding, unfolding, translocation and degradation. They are implicated in various human diseases, including neurodegenerative disorders and cancer. In the present study, we cloned and identified a new gene, DnaJ (HSP40) homolog, subfamily C, member 25 (DNAJC25), which is localized to the cytoplasm. Real-time PCR revealed that the expression of DNAJC25 is particularly high in the liver and is down-regulated in hepatocellular carcinoma (HCC) compared with adjacent normal tissues. The overexpression of DNAJC25 led to an inhibition of colony growth both in quantity and size. Flow cytometry analysis indicated that DNAJC25 also significantly increased cell apoptosis. Our data, therefore, indicate that DNAJC25 plays an important role in hepatocellular carcinogenesis, and should be further studied as a potential tumor suppressor candidate.

Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update

Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participate in many of the traits that permit the malignant phenotype. Thus, cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1/HSP in malignant transformation and (3) discovering approaches to therapy based on disrupting the influence of the HSF1-controlled transcriptome in cancer.

Evidence of prognostic relevant expression profiles of heat-shock proteins and glucose-regulated proteins in oesophageal adenocarcinomas

A high percentage of oesophageal adenocarcinomas show an aggressive clinical behaviour with a significant resistance to chemotherapy. Heat-shock proteins (HSPs) and glucose-regulated proteins (GRPs) are molecular chaperones that play an important role in tumour biology. Recently, novel therapeutic approaches targeting HSP90/GRP94 have been introduced for treating cancer. We performed a comprehensive investigation of HSP and GRP expression including HSP27, phosphorylated (p)-HSP27((Ser15)), p-HSP27((Ser78)), p-HSP27((Ser82)), HSP60, HSP70, HSP90, GRP78 and GRP94 in 92 primary resected oesophageal adenocarcinomas by using reverse phase protein arrays (RPPA), immunohistochemistry (IHC) and real-time quantitative RT-PCR (qPCR). Results were correlated with pathologic features and survival. HSP/GRP protein and mRNA expression was detected in all tumours at various levels. Unsupervised hierarchical clustering showed two distinct groups of tumours with specific protein expression patterns: The hallmark of the first group was a high expression of p-HSP27((Ser15, Ser78, Ser82)) and low expression of GRP78, GRP94 and HSP60. The second group showed the inverse pattern with low p-HSP27 and high GRP78, GRP94 and HSP60 expression. The clinical outcome for patients from the first group was significantly improved compared to patients from the second group, both in univariate analysis (p = 0.015) and multivariate analysis (p = 0.029). Interestingly, these two groups could not be distinguished by immunohistochemistry or qPCR analysis. In summary, two distinct and prognostic relevant HSP/GRP protein expression patterns in adenocarcinomas of the oesophagus were detected by RPPA. Our approach may be helpful for identifying candidates for specific HSP/GRP-targeted therapies.

IGF2BP1: a post-transcriptional "driver" of tumor cell migration

The oncofetal RNA-binding protein IGF2BP1 (IGF2 mRNA binding protein 1) controls the cytoplasmic fate of specific target mRNAs including ACTB and CD44. During neural development, IGF2BPs promote neurite protrusion and the migration of neuronal crest cells. In tumor-derived cells, IGF2BP1 enhances the formation of lamellipodia and invadopodia. Accordingly, the de novo synthesis of IGF2BP1 observed in primary malignancies was reported to correlate with increased metastasis and an overall poor prognosis. However, if and how the protein enhances metastasis remains controversial. In recent studies, we reveal that IGF2BP1 promotes the directed migration of tumor-derived cells in vitro by controlling the expression of MAPK4 and PTEN. The IGF2BP1-facilitated inhibition of MAPK4 mRNA translation interferes with MK5-directed phosphorylation of the heat shock protein 27 (HSP27). This limits G-actin sequestering by phosphorylated HSP27, enhances cell adhesion and elevates the velocity of tumor cell migration. Concomitantly, IGF2BP1 promotes the expression of PTEN by interfering with PTEN mRNA turnover. This results in a shift of cellular PtdIns(3,4,5)P₃/PtdIns(4,5)P₂ ratios and enhances RAC1-dependent cell polarization which finally promotes the directionality of tumor cell migration. These findings identify IGF2BP1 as a potent oncogenic factor that regulates the adhesion, migration and invasiveness of tumor cells by modulating intracellular signaling.

High HSP27 and HSP70 expression levels are independent adverse prognostic factors in primary resected colon cancer

BACKGROUND

The expression of Heat Shock Proteins (HSPs) is increased in various cancers and has been shown to correlate with biological tumor behaviour. This study aimed to investigate the impact of HSP70, HSP60 and HSP27 expression in colon cancer.

MATERIAL AND METHODS

HSP expression was determined by immunohistochemistry on a tissue microarray with 355 primary resected colon carcinomas of all stages. Expression patterns were correlated with pathologic features (UICC pTNM category, tumor grading) and survival.

RESULTS

Expression of HSP27, HSP60 and HSP70 ranged from negative to high. There was no correlation between HSP27, HSP60 and HSP70 expression among each other and with UICC pT category, presence of lymph node or distant metastases or tumor grading. High HSP70 expression was associated with worse overall survival (p < 0.001) and was an independent prognostic factor (p = 0.004) in multivariate analysis including the pathological parameters mentioned above. For patients without lymph node or distant metastases (UICC stages I/II) and with complete tumor excision, HSP70 expression was the only independent prognostic factor for survival (p = 0.001) and superior to UICC pT category. In left sided UICC stage I/II carcinomas, high HSP27 expression also had adverse prognostic impact and was an independent prognostic factor (p = 0.016) besides HSP70 (p = 0.002).

CONCLUSION

High HSP70 and HSP27 expression is associated with worse clinical outcome in colon cancer. Determination of tumoral HSP70 and HSP27 may be used as additional biomarker for risk stratification especially for UICC stage I/II patients.

Assessment of the red cell proteome of young patients with unexplained hemolytic anemia by two-dimensional differential in-gel electrophoresis (DIGE)

Erythrocyte cytosolic protein expression profiles of children with unexplained hemolytic anemia were compared with profiles of close relatives and controls by two-dimensional differential in-gel electrophoresis (2D-DIGE). The severity of anemia in the patients varied from compensated (i.e., no medical intervention required) to chronic transfusion dependence. Common characteristics of all patients included chronic elevation of reticulocyte count and a negative workup for anemia focusing on hemoglobinopathies, morphologic abnormalities that would suggest a membrane defect, immune-mediated red cell destruction, and evaluation of the most common red cell enzyme defects, glucose-6-phosphate dehydrogenase and pyruvate kinase deficiency. Based upon this initial workup and presentation during infancy or early childhood, four patients classified as hereditary nonspherocytic hemolytic anemia (HNSHA) of unknown etiology were selected for proteomic analysis. DIGE analysis of red cell cytosolic proteins clearly discriminated each anemic patient from both familial and unrelated controls, revealing both patient-specific and shared patterns of differential protein expression. Changes in expression pattern shared among the four patients were identified in several protein classes including chaperons, cytoskeletal and proteasome proteins. Elevated expression in patient samples of some proteins correlated with high reticulocyte count, likely identifying a subset of proteins that are normally lost during erythroid maturation, including proteins involved in mitochondrial metabolism and protein synthesis. Proteins identified with patient-specific decreased expression included components of the glutathione synthetic pathway, antioxidant pathways, and proteins involved in signal transduction and nucleotide metabolism. Among the more than 200 proteins identified in this study are 21 proteins not previously described as part of the erythrocyte proteome. These results demonstrate the feasibility of applying a global proteomic approach to aid characterization of red cells from patients with hereditary anemia of unknown cause, including the identification of differentially expressed proteins as potential candidates with a role in disease pathogenesis.

Heat shock protein 70 inhibits hydrogen peroxide-induced nucleolar fragmentation via suppressing cleavage and down-regulation of nucleolin

It has been reported that nucleolar fragmentation is a part of the overall apoptotic morphology, however, it is currently obscure whether and how nucleolar fragmentation can be induced by hydrogen peroxide (H(2)O(2)) and heat shock protein 70 (Hsp70) can prevent nucleolar fragmentation. To dissect these two questions, C(2)C(12) myogenic cells and immortalized mouse embryonic fibroblasts (MEFs) with heat shock transcriptional factor 1 (HSF1) null mutation were treated with heat shock response (HS) (42.5 ± 0.5°C for 1 h and recovery at 37°C for 24 h) and then were insulted with 0.5 mmol/L H(2)O(2). Morphological changes of nucleoli were observed under contrast microscope or electronic microscope. It was found that (1) stimulation with H(2)O(2)-induced nucleolar fragmentation by mediating cleavage and down-regulation of nucleolar protein, nucleolin in C(2)C(12) myocytes and MEFs; (2) HS suppressed nucleolar fragmentation by inducing the expression of Hsp70 in an HSF1-dependent manner as indicated by assays of transfection with Hsp70 antisense oligonucleotides (AS-ONs) or recombinant plasmids of full-length Hsp70 cDNA; (3) protection of Hsp70 against nucleolar fragmentation was related to its accumulation in nucleolus mediated by nuclear localization sequence and its inhibition against cleavage and down-regulation of nucleolin. These results suggested that H(2)O(2)-induced nucleolar fragmentation and HS or Hsp70 inhibit H(2)O(2)-induced nucleolar fragmentation through the translocation of Hsp70 into nucleolar and its protection against impairment of nucleolin.

Heat shock proteins as danger signals for cancer detection

First discovered in 1962, heat shock proteins (HSPs) are highly studied with about 35,500 publications on the subject to date. HSPs are highly conserved, function as molecular chaperones for a large panel of “client” proteins and have strong cytoprotective properties. Induced by many different stress signals, they promote cell survival in adverse conditions. Therefore, their roles have been investigated in several conditions and pathologies where HSPs accumulate, such as in cancer. Among the diverse mammalian HSPs, some members share several features that may qualify them as cancer biomarkers. This review focuses mainly on three inducible HSPs: HSP27, HPS70, and HSP90. Our survey of recent literature highlights some recurring weaknesses in studies of the HSPs, but also identifies findings that indicate that some HSPs have potential as cancer biomarkers for successful clinical applications.

Targeted treatment for chronic lymphocytic leukemia

The treatment of chronic lymphocytic leukemia (CLL) has evolved over the last few decades. Recognition has increased of several key components of CLL biology currently manipulated for therapeutics. A milestone in the treatment of CLL was reached with the incorporation of immunotherapy with conventional chemotherapy. The fludarabine/cyclophosphamide/rituximab combination has demonstrated survival advantage for the first time in the treatment of CLL. Several other biological compounds are being explored with the hope of improving responses, impacting survival, and ultimately curing CLL. Important agents being tested are targeted on CLL surface molecules and their ligands, signal transduction protein and oncogenes. This review provides a brief summary of the recent advances made in preclinical and clinical investigation of selected promising therapeutic agents, which lead the target-directed therapeutic approach.

Heat shock protein as molecular targets for breast cancer therapeutics

Recent advances in the understanding of the molecular mechanisms involved in the breast cancer development and progression have led to the identification of numerous novel molecular targets. Among these, heat shock proteins (HSPs) are being emerging molecular target due to its diverse function in cancer cells. HSPs are highly conserved molecular chaperone that are synthesized by cell in response to various stress conditions. Mammalian HSPs have been classified into several families according to their molecular weight: HSP100, HSP90, HSP72, and small molecular HSPs (including HSP27). They are essential proteins that play a key role in cell survival through the cytoprotective mechanisms. In addition, HSPs are often overexpressed in a rage of cancers including breast cancer, and its overexpression seems to be associated with poor clinical outcomes. Also, HSP90 play a role in facilitating transformation by stabilizing the mutated and overexpressed oncoproteins found in breast cancer cell. Pharmacological targeting of HSP is therefore indicated and in the case of HSP90, numerous inhibitory drugs are undergoing clinical trial for treatment of breast cancer and other cancers. In this review, we describe the roles of HSPs in cancer cell and introduce the HSPs inhibitor as molecular target in cancer therapy and its recent clinical trials in breast cancer.