Protein expression profiles in human breast ductal carcinoma and histologically normal tissue

Extension of the shelf-life of fresh pasta using modified atmosphere packaging and bioprotective cultures

Microbial stability of fresh pasta depends on heat treatment, storage temperature, proper preservatives, and atmosphere packaging. This study aimed at improving the microbial quality, safety, and shelf life of fresh pasta using modified atmosphere composition and packaging with or without the addition of bioprotective cultures (Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium spp., and Bacillus coagulans) into semolina. Three fresh pasta variants were made using (i) the traditional protocol (control), MAP (20:80 CO₂:N₂), and barrier packaging, (ii) the experimental MAP (40:60 CO₂:N₂) and barrier packaging, and (iii) the experimental MAP, barrier packaging, and bioprotective cultures. Their effects on physicochemical properties (i.e., content on macro elements, water activity, headspace O₂, CO₂ concentrations, and mycotoxins), microbiological patterns, protein, and volatile organic compounds (VOC) were investigated at the beginning and the end of the actual or extended shelf-life through traditional and multi-omics approaches. We showed that the gas composition and properties of the packaging material tested in the experimental MAP system, with or without bioprotective cultures, positively affect features of fresh pasta avoiding changes in their main chemical properties, allowing for a storage longer than 120 days under refrigerated conditions. These results support that, although bioprotective cultures were not all able to grow in tested conditions, they can control the spoilage and the associated food-borne microbiota in fresh pasta during storage by their antimicrobials and/or fermentation products synergically. The VOC profiling, based on gas-chromatography mass-spectrometry (GC-MS), highlighted significant differences affected by the different manufacturing and packaging of samples. Therefore, the use of the proposed MAP system and the addition of bioprotective cultures can be considered an industrial helpful strategy to reduce the quality loss during refrigerated storage and to increase the shelf life of fresh pasta for additional 30 days by allowing the economic and environmental benefits spurring innovation in existing production models.

The Chaperone System in Breast Cancer: Roles and Therapeutic Prospects of the Molecular Chaperones Hsp27, Hsp60, Hsp70, and Hsp90

Breast cancer (BC) is a major public health problem, with key pieces of information needed for developing preventive and curative measures still missing. For example, the participation of the chaperone system (CS) in carcinogenesis and anti-cancer responses is poorly understood, although it can be predicted to be a crucial factor in these mechanisms. The chief components of the CS are the molecular chaperones, and here we discuss four of them, Hsp27, Hsp60, Hsp70, and Hsp90, focusing on their pro-carcinogenic roles in BC and potential for developing anti-BC therapies. These chaperones can be targets of negative chaperonotherapy, namely the elimination/blocking/inhibition of the chaperone(s) functioning in favor of BC, using, for instance, Hsp inhibitors. The chaperones can also be employed in immunotherapy against BC as adjuvants, together with BC antigens. Extracellular vesicles (EVs) in BC diagnosis and management are also briefly discussed, considering their potential as easily accessible carriers of biomarkers and as shippers of anti-cancer agents amenable to manipulation and controlled delivery. The data surveyed from many laboratories reveal that, to enhance the understanding of the role of the CS in BS pathogenesis, one must consider the CS as a physiological system, encompassing diverse members throughout the body and interacting with the ubiquitin–proteasome system, the chaperone-mediated autophagy machinery, and the immune system (IS). An integrated view of the CS, including its functional partners and considering its highly dynamic nature with EVs transporting CS components to reach all the cell compartments in which they are needed, opens as yet unexplored pathways leading to carcinogenesis that are amenable to interference by anti-cancer treatments centered on CS components, such as the molecular chaperones.

Bioinformatics analysis for the role of CALR in human cancers

Cancer is one of the most important public health problems in the world. The curative effect of traditional surgery, radiotherapy and chemotherapy is limited and has inevitable side effects. As a potential target for tumor therapy, few studies have comprehensively analyzed the role of CALR in cancers. Therefore, by using GeneCards, UALCAN, GEPIA, Kaplan-Meier Plotter, COSMIC, Regulome Explorer, String, GeneMANIA and TIMER databases, we collected and analyzed relevant data to conduct in-depth bioinformatics research on the CALR expression in Pan-cancer to assess the possibility of CALR as a potential therapeutic target and survival biomarker. We studied the CALR expression in normal human tissues and various tumors of different stages, and found that CALR expression was associated with relapse free survival (RFS). We verified the expression of CALR in breast cancer cell lines by vitro experiments. Mutations of CALR were widely present in tumors. CALR interacted with different genes and various proteins. In tumors, a variety of immune cells are closely related to CALR. In conclusion, CALR can be used as a biomarker for predicting prognosis and a potential target for tumor molecular and immunotherapy.

HSP70s in Breast Cancer: Promoters of Tumorigenesis and Potential Targets/Tools for Therapy

The high frequency of breast cancer worldwide and the high mortality among women with this malignancy are a serious challenge for modern medicine. A deeper understanding of the mechanisms of carcinogenesis and emergence of metastatic, therapy-resistant breast cancers would help development of novel approaches to better treatment of this disease. The review is dedicated to the role of members of the heat shock protein 70 subfamily (HSP70s or HSPA), mainly inducible HSP70, glucose-regulated protein 78 (GRP78 or HSPA5) and GRP75 (HSPA9 or mortalin), in the development and pathogenesis of breast cancer. Various HSP70-mediated cellular mechanisms and pathways which contribute to the oncogenic transformation of mammary gland epithelium are reviewed, as well as their role in the development of human breast carcinomas with invasive, metastatic traits along with the resistance to host immunity and conventional therapeutics. Additionally, intracellular and cell surface HSP70s are considered as potential targets for therapy or sensitization of breast cancer. We also discuss a clinical implication of Hsp70s and approaches to targeting breast cancer with gene vectors or nanoparticles downregulating HSP70s, natural or synthetic (small molecule) inhibitors of HSP70s, HSP70-binding antibodies, HSP70-derived peptides, and HSP70-based vaccines.

The Ginsenoside Rg1 Rescues Mitochondrial Disorders in Aristolochic Acid-Induced Nephropathic Mice

Chronic exposure to aristolochic acid (AA) leads to renal interstitial fibrosis and nephropathy. In this study, we aimed to investigate the renoprotective effects of Panax ginseng extract (GE) and ginsenoside saponin (GS) on AA-induced nephropathy (AAN) in mice. Eighty female C3H/He mice were randomly divided into eight groups, including normal; AA (3 μg/mL for 56 days); AA with GE (125, 250, or 500 mg/kg/d for 14 days); and AA with important GE ingredients, Rg₁, Rb₁, or Rd (5 mg/kg/d for 14 days). Compared with the AA group, renal injuries were significantly decreased in the GE (250 mg/kg/d), Rb₁, and Rg₁ treatment groups. Rg₁ exhibited the best renoprotection among all GS-treated groups. There were 24 peaks significantly altered among normal, AA, and AA + Rg₁ groups, and four mitochondrial proteins were identified, including acyl-CoA synthetase medium-chain family member 2, upregulated during skeletal muscle growth 5 (Usmg5), mitochondrial aconitase 2 (ACO2), and cytochrome c oxidase subunit Va preprotein (COX5a). We demonstrated for the first time that the AAN mechanism and renoprotective effects of Rg₁ are associated with expression of mitochondrial proteins, especially ACO2, Usmg5, and COX5a.

Mitochondrial HSP70 Chaperone System-The Influence of Post-Translational Modifications and Involvement in Human Diseases

Since their discovery, heat shock proteins (HSPs) have been identified in all domains of life, which demonstrates their importance and conserved functional role in maintaining protein homeostasis. Mitochondria possess several members of the major HSP sub-families that perform essential tasks for keeping the organelle in a fully functional and healthy state. In humans, the mitochondrial HSP70 chaperone system comprises a central molecular chaperone, mtHSP70 or mortalin (HSPA9), which is actively involved in stabilizing and importing nuclear gene products and in refolding mitochondrial precursor proteins, and three co-chaperones (HSP70-escort protein 1-HEP1, tumorous imaginal disc protein 1-TID-1, and Gro-P like protein E-GRPE), which regulate and accelerate its protein folding functions. In this review, we summarize the roles of mitochondrial molecular chaperones with particular focus on the human mtHsp70 and its co-chaperones, whose deregulated expression, mutations, and post-translational modifications are often considered to be the main cause of neurological disorders, genetic diseases, and malignant growth.

Intracellular leucine-rich alpha-2-glycoprotein-1 competes with Apaf-1 for binding cytochrome c in protecting MCF-7 breast cancer cells from apoptosis

Leucine-rich alpha-2-glycoprotein-1 (LRG1) has been shown to compete with apoptosis activating factor-1 (Apaf-1) for binding cytochrome c (Cyt c) and could play a role in inhibition of apoptosis. Employing MCF-7 breast cancer cells, we report that intracellular LRG1 does protect against apoptosis. Thus, cells transfected with the lrg1 gene and expressing higher levels of LRG1 were more resistant to hydrogen peroxide-induced apoptosis than parental cells, while cells in which LRG mRNA was knocked down by short hairpin (sh) RNA-induced degradation were more sensitive. The amount of Cyt c co-immunoprecipitated with Apaf-1 from the cytosol of apoptotic cells was inversely related to the level of LRG1 expression. In lrg1-transfected cells partially-glycosylated LRG1 was found in the cytosol and there was an increase in cytosolic Cyt c in live lrg1-transfected cells relative to parental cells. However, apoptosis was not spontaneously induced because Cyt c was bound to LRG1 and not to Apaf-1. Cyt c was the only detectable protein co-immunoprecipitated with LRG1. Following hydrogen peroxide treatment degradation of LRG1 allowed for induction of apoptosis. We propose that intracellular LRG1 raises the threshold of cytoplasmic Cyt c required to induce apoptosis and, thus, prevents onset of the intrinsic pathway in cells where Cyt c release from mitochondria does not result from committed apoptotic signaling. This mechanism of survival afforded by LRG1 is likely to be distinct from its extracellular survival function that has been reported by several research groups.

Impact of Enzymatic and Microbial Bioprocessing on Antioxidant Properties of Hemp (Cannabis sativa L.)

Although the hemp seed boasts high nutritional and functional potential, its use in food preparations is still underestimated due to scarce technological properties and the presence of several anti-nutritional factors. Here, an optimization of a biotechnological protocol aimed at improving the antioxidant properties and the protein digestibility of the whole hemp seed has been proposed. Processing based on the use of commercial food grade enzymes and ad hoc selected lactic acid bacteria was tested and the phenolic and protein profiles were investigated through an integrated approach including selective extraction, purification, and identification of the potentially active compounds. The influence of the bioprocessing on the antioxidant activity of the hemp was evaluated both in vitro and on human keratinocytes. The lactic acid bacteria fermentation was the best method to significantly improve the antioxidant potential of the hemp through intense proteolysis which led to both the release of bioactive peptides and the increase in the protein digestibility. Moreover, changes in the phenolic profile allowed a significant protective effect against oxidative stress measured on the human keratinocyte cell line.

Identification of potential molecular pathways involved in prostate carcinogenesis in offspring exposed to maternal malnutrition

The developmental origins of health and disease concept links adult diseases with early-life exposure to inappropriate environmental conditions. Intrauterine and postnatal malnutrition may lead to an increased incidence of type 2 diabetes, obesity, and cardiovascular diseases. Maternal malnutrition (MM) has also been associated with prostate carcinogenesis. However, the molecular mechanisms associated with this condition remain poorly understood. Using a proteomic analysis, we demonstrated that MM changed the levels of proteins associated with growth factors, estrogen signaling, detoxification, and energy metabolism in the prostate of both young and old rats. These animals also showed increased levels of molecular markers of endoplasmic reticulum function and histones. We further performed an in silico analysis that identified commonly deregulated proteins in the ventral prostate of old rats submitted to MM with a mouse model and patients with prostate cancer. In conclusion, our results demonstrated that estrogenic signaling pathways, endoplasmic reticulum functions, energy metabolism, and molecular sensors of protein folding and Ca2+ homeostasis, besides histone, and RAS-GTPase family appear to be involved in this process. Knowledge of these factors may raise discussions regarding the role of maternal dietary intervention as a public policy for the lifelong prevention of chronic diseases.

Unexpected therapeutic effects of cisplatin

Cisplatin is a widely used chemotherapeutic agent that is clinically approved to fight both carcinomas and sarcomas. It has relatively high efficiency in treating ovarian cancers and metastatic testicular cancers. It is generally accepted that the major mechanism of cisplatin anti-cancer action is DNA damage. However, cisplatin is also effective in metastatic cancers and should, therefore, affect slow-cycling cancer stem cells in some way. In this review, we focused on the alternative effects of cisplatin that can support a good therapeutic response. First, attention was paid to the effects of cisplatin at the cellular level such as changes in intracellular pH and cellular mechanical properties. Alternative cellular targets of cisplatin, and the effects of cisplatin on cancer cell metabolism and ER stress were also discussed. Furthermore, the impacts of cisplatin on the tumor microenvironment and in the whole organism context were reviewed. In this review, we try to reveal possible causes of the unexpected effectiveness of this anti-cancer drug.

Calreticulin regulates vascular endothelial growth factor-A mRNA stability in gastric cancer cells

Calreticulin (CRT) and vascular endothelial growth factor-A (VEGF-A) are crucial for angiogenesis, and mediate multiple malignant behaviors in gastric cancer. In this study, we report that CRT is positively correlated with VEGF-A in gastric cancer patients. Moreover, high expressions of both CRT and VEGF-A are markedly associated with the pathological stage, progression, and poor prognosis in the patients. Therefore, we sought to elucidate the mechanism by which CRT affects VEGF-A in gastric cancer. Firstly, we demonstrate the novel finding that knockdown of CRT reduced VEGF-A mRNA stability in two gastric cancer cell lines, AGS and MKN45. The AU-Rich element (ARE) is believed to play a crucial role in the maintenance of VEGF-A mRNA stability. Luciferase reporter assay shows that knockdown of CRT significantly decreased the activity of renilla luciferase with VEGF-A ARE sequence. Additionally, competition results from RNA-binding/electrophoretic mobility shift assay indicate that CRT forms an RNA-protein complex with the VEGF-A mRNA by binding to the ARE. In addition, the proliferation rate of human umbilical vein endothelial cells (HUVEC) was significantly reduced when treated with conditioned medium from CRT knockdown cells; this was rescued by exogenous VEGF-A recombinant protein. Our results demonstrate that CRT is involved in VEGF-A ARE binding protein complexes to stabilize VEGF-A mRNA, thereby promoting the angiogenesis, and progression of gastric cancer.

Novel serum markers HSP60, CHI3L1, and IGFBP-2 in metastatic colorectal cancer

Colorectal cancer (CRC) is the second leading tumor diagnosis in women and men in the Czech Republic. Patient outcome depends on tumor stage at the time of diagnosis and, in metastatic disease, on the localization and extent of distant metastases. The early detection of metastatic liver disease is an important indication for liver surgery. Therefore, novel biomarkers are urgently required. Serum samples were collected from 97 patients with histologically confirmed metastatic CRC at the time of diagnosis or at the time of progression during palliative treatment, and 79 samples from healthy controls. All patients exhibited adequate liver and renal function and signed informed consent was obtained from all patients included in the current study. The serum levels of Heat shock protein 60 (HSP60), Chitinase-3-like protein 1 (CHI3L1) and Insulin-like growth factor binding protein 2 (IGFBP-2) were measured using immunochemistry. The serum levels of HSP60, CHI3L1 and IGFBP-2 were significantly higher in patients with CRC compared with healthy controls. When compared with carcinoembryonic antigen (CEA), HSP60 exhibited the same sensitivity and specificity, while CHI3L1 and IGFBP-2 exhibited decreased sensitivity. Additionally, the serum levels of HSP60 and IGFBP-2 were indicated to be correlated with the presence of liver metastases, which is in contrast to CEA and Cancer antigen 19-9 (CA19-9). Patients with higher HSP60 and IGFBP-2 levels exhibited a significantly worse survival (P<0.001 and 0.007, respectively). The results of the current study indicate HSP60 to be an effective biomarker in patients with metastatic CRC, with it exhibiting an equal sensitivity to CEA. Additionally, HSP60 and IGFBP-2 levels also strongly correlated with extension of liver metastases and exhibited a prognostic value that contrasted that of CEA.

The Multiple Roles and Therapeutic Potential of Molecular Chaperones in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancer types in men worldwide. Heat shock proteins (HSPs) are molecular chaperones that are widely implicated in the pathogenesis, diagnosis, prognosis, and treatment of many cancers. The role of HSPs in PCa is complex and their expression has been linked to the progression and aggressiveness of the tumor. Prominent chaperones, including HSP90 and HSP70, are involved in the folding and trafficking of critical cancer-related proteins. Other members of HSPs, including HSP27 and HSP60, have been considered as promising biomarkers, similar to prostate-specific membrane antigen (PSMA), for PCa screening in order to evaluate and monitor the progression or recurrence of the disease. Moreover, expression level of chaperones like clusterin has been shown to correlate directly with the prostate tumor grade. Hence, targeting HSPs in PCa has been suggested as a promising strategy for cancer therapy. In the current review, we discuss the functions as well as the role of HSPs in PCa progression and further evaluate the approach of inhibiting HSPs as a cancer treatment strategy.

Proteomic Strategies and their Application in Cancer Research

The understanding of carcinogenesis and tumor progression on a molecular basis needs a detailed study of proteins as effector molecules and as critical components of the multiple interconnected signaling pathways that drive the neoplastic phenotype. Thus, the proteomic approach represents a powerful tool for the challenge of the post-genomic era. The term “cancer proteome” refers to the collection of proteins expressed by a given cancer cell and should be considered as a highly dynamic entity within the cell, which affects a variety of cellular activities. The emerging proteomic analysis platforms including 2D-PAGE, mass spectrometry technologies, and protein microarrays represent powerful tools to study and understand cancer. These systems aim to not only identify, catalogue, and characterize cancer proteins, but also to unveil how they interact to affect overall tumor progression. Moreover, recent studies on various cancers have reported promising results concerning the detection of novel molecular biomarkers useful in the early diagnosis of cancer and in drug discovery. Thus, a new subdiscipline named clinical proteomics, concomitant with new molecular technologies that are developed, demonstrates promise to discover new cancer biomarkers. The early diagnosis of cancer, even in a premalignant state, is crucial for the successful treatment of this disease. For these reasons, it is clear that the identification of biomarkers for the early diagnosis of cancer should represent one of the main goals of this emerging field of study.

Mass spectrometric characterization of the zein protein composition in maize flour extracts upon protein separation by SDS-PAGE and 2D gel electrophoresis

Highly homogenous α zein protein was isolated from maize kernels in an environment-friendly process using 95% ethanol as solvent. Due to the polyploidy and genetic polymorphism of the plant source, the application of high resolution separation methods in conjunction with precise analytical methods, such as MALDI-TOF-MS, is required to accurately estimate homogeneity of products that contain natural zein protein. The α zein protein product revealed two main bands in SDS-PAGE analysis, one at 25 kDa and other at 20 kDa apparent molecular mass. Yet, high resolution 2DE revealed approximately five protein spot groups in each row, the first at ca. 25 kDa and the second at ca. 20 kDa. Peptide mass fingerprinting data of the proteins in the two dominant SDS-PAGE bands matched to 30 amino acid sequence entries out of 102 non-redundant data base entries. MALDI-TOF-MS peptide mapping of the proteins from all spots indicated the presence of only α zein proteins. The most prominent ion signals in the MALDI mass spectra of the protein mixture of the 25 kDa SDS gel band after in-gel digestion were found at m/z 1272.6 and m/z 2009.1, and the most prominent ion signals of the protein mixture of the 20 kDa band after in-gel digestion were recorded at m/z 1083.5 and m/z 1691.8. These ion signals have been found typical for α zein proteins and may serve as marker ion signals which upon chymotryptic digestion reliably indicate the presence of α zein protein in two hybrid corn products.

The metastasis suppressor, NDRG1, differentially modulates the endoplasmic reticulum stress response

The metastasis suppressor, N-myc downstream regulated gene-1 (NDRG1), is a stress response protein that is involved in the inhibition of multiple oncogenic signaling pathways. Initial studies have linked NDRG1 and the endoplasmic reticulum (ER) stress response. Considering this, we extensively examined the mechanism by which NDRG1 regulates the ER stress response in pancreatic and colon cancer cells. We also examined the anti-cancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), which induces NDRG1 expression and causes ER stress. The expression of NDRG1 was demonstrated to regulate the three main arms of the ER stress response by: (1) increasing the expression of three major ER chaperones, binding immunoglobulin protein (BiP), calreticulin, and calnexin; (2) suppressing the protein kinase, RNA-activated (PKR)-like ER kinase (PERK); (3) inhibiting the inositol-requiring kinase 1α (IRE1α) arm; and (4) increasing the cleavage of activating transcription factor 6 (ATF6). An important finding was that NDRG1 enhances the anti-proliferative and anti-migratory activity of Dp44mT. This increased efficacy could be related to the following effects in the presence of Dp44mT and NDRG1, namely: markedly increased activation of the PERK target, eukaryotic translation initiation factor 2α (eIF2α); the maintenance of activating transcription factor 4 (ATF4) expression; high cytosolic Ca⁺² that increases the sensitivity of cells to apoptosis via activation of the calmodulin-dependent kinase II (CaMKII) signaling cascade; and increased pro-apoptotic C/EBP-homologous protein (CHOP) expression. Collectively, this investigation dissects the molecular mechanisms through which NDRG1 manipulates the ER stress response and its ability to potentiate the activity of the potent anti-cancer agent, Dp44mT.

Calreticulin is Differentially Expressed in Invasive Ductal Carcinoma: A Comparative Study

Materials & Methods:

Breast tissue profiles were made after polytron tissue lysis and rehydrated proteins were further characterized by using two-dimensional gel electrophoresis. On the basis of isoelectric point (pI) and molecular weight, proteins were identified by online tool named Siena 2-D database and their identification was further confirmed by using MALDI-TOF.

Results:

Among identified spots, 10 proteins were found to be differentially expressed i.e.; COX5A, THIO, TCTP, HPT, SODC, PPIA, calreticulin (CRT), HBB, albumin and serotransferrin. For further investigation, CRT was selected. The level of CRT in tumors was found to be significantly higher than in normal group (p < 0.05). The increased expression of CRT level in tumor was statistically significant (p = 0.010) at a 95% confidence level (p < 0.05) as analyzed by Mann-Whitney. CRT was found distinctly expressed in high amount in tumor tissue as compared to their matched normal tissues.

Conclusion:

It has been concluded that CRT expression could discriminate between normal tissue and tumor tissue so it might serve as a possible candidate for future studies in cancer diagnostic markers.

Macrophage Migration Inhibitory Factor protects cancer cells from immunogenic cell death and impairs anti-tumor immune responses

The Macrophage Migration Inhibitory Factor (MIF) is an inflammatory cytokine that is overexpressed in a number of cancer types, with increased MIF expression often correlating with tumor aggressiveness and poor patient outcomes. In this study, we aimed to better understand the link between primary tumor expression of MIF and increased tumor growth. Using the MMTV-PyMT murine model of breast cancer, we observed that elevated MIF expression promoted tumor appearance and growth. Supporting this, we confirmed our previous observation that higher MIF expression supported tumor growth in the 4T1 murine model of breast cancer. We subsequently discovered that loss of MIF expression in 4T1 cells led to decreased cell numbers and increased apoptosis in vitro under reduced serum culture conditions. We hypothesized that this increase in cell death would promote detection by the host immune system in vivo, which could explain the observed impairment in tumor growth. Supporting this, we demonstrated that loss of MIF expression in the primary tumor led to an increased abundance of intra-tumoral IFNgamma-producing CD4+ and CD8+ T cells, and that depletion of T cells from mice bearing MIF-deficient tumors restored growth to the level of MIF-expressing tumors. Furthermore, we found that MIF depletion from the tumor cells resulted in greater numbers of activated intra-tumoral dendritic cells (DCs). Lastly, we demonstrated that loss of MIF expression led to a robust induction of a specialized form of cell death, immunogenic cell death (ICD), in vitro. Together, our data suggests a model in which MIF expression in the primary tumor dampens the anti-tumor immune response, promoting tumor growth.

Toward Developing Chemical Modulators of Hsp60 as Potential Therapeutics

The 60 kDa heat shock protein (Hsp60) is classically known as a mitochondrial chaperonin protein working together with co-chaperonin 10 kDa heat shock protein (Hsp10). This chaperonin complex is essential for folding proteins newly imported into mitochondria. However, Hsp60, and/or Hsp10 have also been shown to reside in other subcellular compartments including extracellular space, cytosol, and nucleus. The proteins in these extra-mitochondrial compartments may possess a wide range of functions dependent or independent of its chaperoning activity. But the mechanistic details remain unknown. Mutations in Hsp60 gene have been shown to be associated with neurodegenerative disorders. Abnormality in expression level and/or subcellular localization have also been detected from different diseased tissues including inflammatory diseases and various cancers. Therefore, there is a strong interest in developing small molecule modulators of Hsp60. Most of the reported inhibitors were discovered through various chemoproteomics strategies. In this review, we will describe the recent progress in this area with reported inhibitors from both natural products and synthetic compounds. The former includes mizoribine, epolactaene, myrtucommulone, stephacidin B, and avrainvillamide while the latter includes o-carboranylphenoxyacetanilides and gold (III) porphyrins. The potencies of the known inhibitors range from low micromolar to millimolar concentrations. The potential applications of these inhibitors include anti-cancer, anti-inflammatory diseases, and anti-autoimmune diseases.

Hsp60 exerts a tumor suppressor function by inducing cell differentiation and inhibiting invasion in hepatocellular carcinoma

Heat shock protein 60 (Hsp60), a typical mitochondrial chaperone, is associated with progression of various cancers. However, its expression and significance in hepatocellular carcinoma (HCC) remain largely unclear. In the present study, the mRNA and protein expression of Hsp60 in HCC tissues were detected by quantitative RT-PCR (n=24), western blot (n=7), and immunohistochemical staining (n=295), respectively. The correlation between Hsp60 expression and clinicopathological characteristics of HCC patient was also analyzed. Meanwhile, the influence of Hsp60 on malignant phenotype of HCC cells was further investigated. We found that expression of Hsp60 was significantly downregulated in HCC tissues compared to peritumor tissues. Hsp60 expression was significantly correlated with serum alpha -foetoprotein (AFP) level and tumor differentiation grade. Moreover, high Hsp60 expression cancer/pericancer (C/P) ratio was associated with a better overall survival rate (P=0.035, n=295). The prognostic implication of Hsp60 in HCC was further confirmed in another cohort of 107 HCC patients (P=0.027). Up-regulation of Hsp60 remarkably induced the cell differentiation and inhibited the invasive potential of HCC in vitro and in vivo. Intriguingly, the down-regulation of Hsp60 significantly impaired mitochondrial biogenesis. Although more data are required to clarify the underling mechanism responsible for function of Hsp60, our results suggested that the effect of Hsp60 on differentiation and invasion of HCC cells might be associated with mitochondrial biogenesis. Collectively, our findings indicated that Hsp60 exerted a tumor suppressor function, and might serve as a potential therapeutic target in the treatment of HCC.

Role of TCTP for Cellular Differentiation and Cancer Therapy

The translationally controlled tumor protein (TCTP) is a highly conserved protein that is regulated due to a high number of extracellular stimuli. TCTP has an important role for cell cycle and normal development. On the other side, tumor reversion and malignant transformation have been associated with TCTP. TCTP has been found among the 12 genes that are differentially expressed during mouse oocyte maturation, and an overexpression of this gene was reported in a wide variety of different cancer types. Its antiapoptotic effect is indicated by the interaction with several proapoptotic proteins of the Bcl-2 family and the p53 tumor suppressor protein. In this article, we draw attention to the role of TCTP in cancer, especially, focusing on cell differentiation and tumor reversion, a biological process by which highly tumorigenic cells lose their malignant phenotype. This protein has been shown to be the most strongly downregulated protein in revertant cells compared to the parental cancer cells. Decreased expression of TCTP results either in the reprogramming of cancer cells into reversion or apoptosis. As conventional chemotherapy is frequently associated with the development of drug resistance and high toxicity, the urge for the development of new or additional scientific approaches falls into place. Differentiation therapy aims at reinducing differentiation backward to the nonmalignant cellular state. Here, different approaches have been reported such as the induction of retinoid pathways and the use of histone deacetylase inhibitors. Also, PPARγ agonists and the activation of the vitamin D receptor have been reported as potential targets in differentiation therapy. As TCTP is known as the histamine-releasing factor, antihistaminic drugs have been shown to target this protein. Antihistaminic compounds, hydroxyzine and promethazine, inhibited cell growth of cancer cells and decreased TCTP expression of breast cancer and leukemia cells. Recently, we found that two antihistaminics, levomepromazine and buclizine, inhibited cancer cell growth by direct binding to TCTP and induction of cell differentiation. These data confirmed that TCTP is an exquisite target for anticancer differentiation therapy and antihistaminics have potential to be lead compounds for the direct interaction with TCTP as new inhibitors of human TCTP and tumor growth.

Detection of cell surface calreticulin as a potential cancer biomarker using near-infrared emitting gold nanoclusters

Calreticulin (CRT) is a cytoplasmic calcium-binding protein. The aim of this study was to investigate CRT presence in cancer with the use of fluorescent gold nanoclusters (AuNCs) and to explore AuNC synthesis using mercaptosuccinic acid (MSA) as a coating agent. MSA-coated AuNCs conferred well-dispersed, bio-stable, water-soluble nanoparticles with bioconjugation capacity and 800-850 nm fluorescence after broad-band excitation. Cell-viability assay revealed good AuNC tolerability. A native CRT amino-terminus corresponding peptide sequence was synthesised and used to generate rabbit site-specific antibodies. Target specificity was demonstrated with antibody blocking in colorectal and breast cancer cell models; human umbilical vein endothelial cells served as controls. We demonstrated a novel route of AuNC/MSA manufacture and CRT presence on colonic and breast cancerous cell surface. AuNCs served as fluorescent bio-probes specifically recognising surface-bound CRT. These results are promising in terms of AuNC application in cancer theranostics and CRT use as surface biomarker in human cancer.

Calreticulin mediates an invasive breast cancer phenotype through the transcriptional dysregulation of p53 and MAPK pathways

BACKGROUND

The introduction of effective novel biomarkers of invasion and metastasis is integral for the advancement of breast cancer management. The present study focused on the identification and evaluation of calreticulin (CRT) as a potential biomarker for breast cancer invasion.

METHODS

Two-dimensional gel protein electrophoresis and MALDI-TOF were utilized in the analysis of fresh-frozen invasive intra-ductal carcinoma specimens. Calreticulin-associated expression was analyzed using immunohistochemistry of FFPE non-malignant/malignant breast specimens. A CRT-knockdown model of MCF7 cell line was developed using siRNA and the CRT genotype/phenotype correlations based on migration and trans-well invasion assays were determined. Finally, microarray-based global gene expression profiling was conducted to elucidate the possible calreticulin pro-invasive regulatory pathways.

RESULTS

Two-dimensional gel protein electrophoresis and MALDI-TOF analysis showed upregulation of calreticulin expression in tumor tissues as compared to the normal adjacent tissues. Meta-analysis of the immunohistochemical results confirmed significantly higher expression of calreticulin (p < 0.05) in the stromal compartments of malignant tissues as compared to non-malignant tissues. Migration and transwell invasion assays showed significant loss in the migratory and invasive potential of CRT-knockdown cells (p < 0.05). Global gene expression profiling successfully identified various putative gene networks such as p53 and MAPK pathways that are involved in calreticulin breast cancer signaling.

CONCLUSION

Besides confirming calreticulin overexpression in invasive breast cancer tissues, this study reveals a calreticulin-dependent pro-invasive potential and suggests possible contributing pathways. Defining the mechanistic role of invasion and characterizing the possible calreticulin-dependent molecular targets will be the focus of future work.

Molecular dynamics-based identification of novel natural mortalin-p53 abrogators as anticancer agents

INTRODUCTION

Cancer is one of the leading causes of mortality worldwide that requires attention in terms of extensive study and research. Eradication of mortalin-p53 interaction that leads to the inhibition of transcriptional activation or blocking of p53 from functioning as a suppressor and induction of nuclear translocation of p53 can prove to be one of the useful approaches for cancer management.

RESULTS

In this study, we used structure-based approach to target the p53-binding domain of mortalin in order to prevent mortalin-p53 complex formation. We screened compounds from ZINC database against the modeled mortalin protein using Glide virtual screening. The top two compounds, DTOM (ZINC 28639308) and TTOM (ZINC 38143676) with Glide score of -12.27 and -12.16, respectively, were identified with the potential to abrogate mortalin-p53 interaction. Finally, molecular dynamics simulations were used to analyze the dynamic stability of the ligand-bound complex and it was observed that residues Tyr196, Asn198, Val264 and Thr267 were involved in intermolecular interactions in both the simulated ligand-bound complexes, and thus, these residues may have a paramount role in stabilizing the binding of the ligands with the protein.

CONCLUSION

These detailed insights can further facilitate the development of potent inhibitors against mortalin-p53 complex.

Melanoma and the Unfolded Protein Response

The UPR (unfolded protein response) has been identified as a key factor in the progression and metastasis of cancers, notably melanoma. Several mediators of the UPR are upregulated in cancers, e.g., high levels of GRP78 (glucose-regulator protein 78 kDa) correlate with progression and poor outcome in melanoma patients. The proliferative burden of cancer induces stress and activates several cellular stress responses. The UPR is a tightly orchestrated stress response that is activated upon the accumulation of unfolded proteins within the ER (endoplasmic reticulum). The UPR is designed to mediate two conflicting outcomtes, recovery and apoptosis. As a result, the UPR initiates a widespread signaling cascade to return the cell to homeostasis and failing to achieve cellular recovery, initiates UPR-induced apoptosis. There is evidence that ER stress and subsequently the UPR promote tumourigenesis and metastasis. The complete role of the UPR has yet to be defined. Understanding how the UPR allows for adaption to stress and thereby assists in cancer progression is important in defining an archetype of melanoma pathology. In addition, elucidation of the mechanisms of the UPR may lead to development of effective treatments of metastatic melanoma.

Functional roles of calreticulin in cancer biology

Calreticulin is a highly conserved endoplasmic reticulum chaperone protein which participates in various cellular processes. It was first identified as a Ca²⁺-binding protein in 1974. Accumulated evidences indicate that calreticulin has great impacts for the development of different cancers and the effect of calreticulin on tumor formation and progression may depend on cell types and clinical stages. Cell surface calreticulin is considered as an “eat-me” signal and promotes phagocytic uptake of cancer cells by immune system. Moreover, several reports reveal that manipulation of calreticulin levels profoundly affects cancer cell proliferation and angiogenesis as well as differentiation. In addition to immunogenicity and tumorigenesis, interactions between calreticulin and integrins have been described during cell adhesion, which is an essential process for cancer metastasis. Integrins are heterodimeric transmembrane receptors which connect extracellular matrix and intracellular cytoskeleton and trigger inside-out or outside-in signaling transduction. More and more evidences reveal that proteins binding to integrins might affect integrin-cytoskeleton interaction and therefore influence ability of cell adhesion. Here, we reviewed the biological roles of calreticulin and summarized the potential mechanisms of calreticulin in regulating mRNA stability and therefore contributed to cancer metastasis.

HBx co-localizes with COXIII in HL-7702 cells to upregulate mitochondrial function and ROS generation

Hepatocellular carcinoma (HCC) is one of the most common malignant diseases, and HBx leads to the development of HBV-associated HCC. Mitochondria are key organelles that regulate apoptosis, cellular energetics and signal transduction pathways, and are the source of HBx-induced reactive oxygen species (ROS). Recent findings have shown that HBx interacts with the inner mitochondrial membrane protein, COXIII, via the yeast two-hybrid system, mating experiment and coimmunoprecipitation. The aim of the present study was to examine the co-localizaiton of HBx and COXIII in HL-7702 cells and to investigate ensuing alterations of mitochondrial function. An HL-7702 cell line stably expressing the HBx gene by lentivirus vectors was constructed. Confocal microscopy was utilized to assess the interaction between HBx protein and COXIII. Expression of COXIII, activities of cytochrome c oxidase (COX) and the mitochondrial membrane potential, which were functionally relevant to the HBx protein-COXIII interaction, were investigated in cell cultures. Moreover, the intracellular ROS levels were detected by flow cytometry. The results demonstrated that HBx co-localized with the inner mitochondrial protein, COXIII, in HL-7702 cells, causing the upregulation of COXIII protein expression as well as COX activity. However, HBx did not alter the mitochondrial membrane potential and mitochondria exhibited only slight swelling in HL-7702-HBx cells. Moreover, HBx elevated the generation of mitochondrial ROS in HL-7702-HBx cells. The main finding of the present study was that the co-localization of HBx and COXIII leads to upregulation of the mitochondrial function and ROS generation, which are associated with the oncogenesis of HBV-associated HCC.

Detection of tumor-associated antigens in culture supernatants using autoantibodies in sera from patients with bladder cancer

Secreted proteins play essential roles in the process of tumorigenesis, and the analysis of tumor-secreted proteins has been suggested as a promising strategy for identifying cancer biomarkers. In this study, we performed proteomic analysis to identify proteins secreted from bladder cancer cell lines that are recognized by autoantibodies in sera from patients with bladder cancer. In addition,autoantibodies against the identified proteins were validated using a dot-blot array with sera from patients with bladder cancer and normal controls. As the results, we detected twenty-five and thirty-two immunoreactive spots in sera from patients with high- and low-grade bladder cancer, respectively.In addition, validation analysis revealed that serum IgG levels of anti-calreticulin and matrix metalloproteinase-2 (MMP2) autoantibodies were significantly higher in bladder cancer patients than in normal controls (both P < 0.05). Furthermore, the serum IgG level of anti-MMP2 autoantibody was significantly higher in patients with high- compared to low-grade bladder cancer(P < 0.05). On multivariate analysis, the serum IgG level of anti-MMP2 autoantibody was an independent predictor of cancer-specific survival (P < 0.05). Based on these findings, serum IgG levels of anti-calreticulin and MMP2 autoantibodies may be novel biomarker candidates for bladder cancer and its clinical outcome.

Profiling the mitochondrial proteome of Leber's Hereditary Optic Neuropathy (LHON) in Thailand: down-regulation of bioenergetics and mitochondrial protein quality control pathways in fibroblasts with the 11778G>A mutation

Leber's Hereditary Optic Neuropathy (LHON) is one of the commonest mitochondrial diseases. It causes total blindness, and predominantly affects young males. For the disease to develop, it is necessary for an individual to carry one of the primary mtDNA mutations 11778G>A, 14484T>C or 3460G>A. However these mutations are not sufficient to cause disease, and they do not explain the characteristic features of LHON such as the higher prevalence in males, incomplete penetrance, and relatively later age of onset. In order to explore the roles of nuclear encoded mitochondrial proteins in development of LHON, we applied a proteomic approach to samples from affected and unaffected individuals from 3 pedigrees and from 5 unrelated controls. Two-dimensional electrophoresis followed by MS/MS analysis in the mitochondrial lysate identified 17 proteins which were differentially expressed between LHON cases and unrelated controls, and 24 proteins which were differentially expressed between unaffected relatives and unrelated controls. The proteomic data were successfully validated by western blot analysis of 3 selected proteins. All of the proteins identified in the study were mitochondrial proteins and most of them were down regulated in 11778G>A mutant fibroblasts. These proteins included: subunits of OXPHOS enzyme complexes, proteins involved in intermediary metabolic processes, nucleoid related proteins, chaperones, cristae remodelling proteins and an anti-oxidant enzyme. The protein profiles of both the affected and unaffected 11778G>A carriers shared many features which differed from those of unrelated control group, revealing similar proteomic responses to 11778G>A mutation in both affected and unaffected individuals. Differentially expressed proteins revealed two broad groups: a cluster of bioenergetic pathway proteins and a cluster involved in protein quality control system. Defects in these systems are likely to impede the function of retinal ganglion cells, and may lead to the development of LHON in synergy with the primary mtDNA mutation.

Targeting the heat shock protein 90: a rational way to inhibit macrophage migration inhibitory factor function in cancer

PURPOSE OF REVIEW

Macrophage migration inhibitory factor (MIF), originally identified as a proinflammatory cytokine, is highly elevated in many human cancer types, independent of their histological origin. MIF's tumour promoting activities correlate with tumour aggressiveness and poor clinical prognosis. Genetic depletion of MIF in mouse cancer models results in significant inhibition of cell proliferation and induction of apoptosis, making it an attractive target for anticancer therapies. Here, we summarize the current possibilities to inhibit MIF function in cancer.

RECENT FINDINGS

All known small molecule MIF inhibitors antagonize MIF's enzymatic function. However, a recent knockin mouse model suggested that protein interactions play a bigger biological role in tumour cell growth regulation than MIF's enzymatic activity. Thus, alternative strategies are important for targeting MIF. Recently, we identified that MIF in cancer cells is highly stabilized through the heat shock protein 90 machinery (HSP90). Thus, MIF is an HSP90 client. Pharmacological inhibition of the Hsp90 ATPase activity results in MIF degradation in several types of cancer cells. This provides a new way to inhibit MIF function independent of its enzymatic activity.

SUMMARY

Targeting the HSP90 machinery is a promising way to inhibit MIF function in cancer. Along with MIF and dependent on the molecular make-up of the tumour, a large number of other critical tumourigenic proteins are also destabilized by HSP90 inhibition, overall resulting in a profound block of tumour growth.

Exploitation of Albanian wheat cultivars: characterization of the flours and lactic acid bacteria microbiota, and selection of starters for sourdough fermentation

Six Albanian soft and durum wheat cultivars were characterized based on chemical and technological features, showing different attitudes for bread making. Gliadin and glutenin fractions were selectively extracted from flours, and subjected to two-dimensional electrophoresis. Linja 7 and LVS flours showed the best characteristics, and abundance of high molecular weight (HMW)-glutenins. Type I sourdoughs were prepared through back slopping procedure, and the lactic acid bacteria were typed and identified. Lactobacillus plantarum and Leuconostoc mesenteroides were the predominant species. Thirty-eight representative isolates were singly used for sourdough fermentation of soft and durum wheat Albanian flours and their selection was carried out based on growth and acidification, quotient of fermentation, and proteolytic activity. Two different pools of lactic acid bacteria were designed to ferment soft or durum wheat flours. Sourdough fermentation with mixed and selected starters positively affected the quotient of fermentation, concentration of free amino acids, profile of phenolic acids, and antioxidant and phytase activities. This study provided the basis to exploit the potential of wheat Albanian flours based on an integrated approach, which considered the characterization of the flours and the processing conditions.

TCTP as therapeutic target in cancers

The translationally controlled tumor protein (TCTP) is a highly conserved protein present in eukaryotic organisms. This protein, located both in the cytoplasmic and the nucleus, is expressed in various tissues and is regulated in response to a wide range of extracellular stimuli. TCTP interacts with itself and other protein including MCL1 and p53. TCTP has been shown to play an important role in physiological events, such as cell proliferation, cell death and immune responses but also in stress response and tumor reversion. Moreover, TCTP expression is associated with malignancy and chemoresistance. In this review, we will evaluate pathways regulated by TCTP and current inhibitory strategy to target TCTP in cancerous diseases.

Cancer phototherapy via selective photoinactivation of respiratory chain oxidase to trigger a fatal superoxide anion burst

AIMS

Here, we develop a novel cancer treatment modality using mitochondria-targeting, high-fluence, low-power laser irradiation (HF-LPLI) in mouse tumor models and explore the mechanism of mitochondrial injury by HF-LPLI.

RESULTS

We demonstrated that the initial reaction after photon absorption was photosensitization of cytochrome c oxidase (COX), to inhibit enzymatic activity of COX in situ and cause respiratory chain superoxide anion (O2(-•)) burst. We also found that HF-LPLI exerted its main tumor killing effect through mitochondrial O2(-•) burst via electron transport chain (ETC). These phenomena were completely absent in the respiration-deficient cells and COX knockdown cells. With a carefully selected irradiation protocol, HF-LPLI could efficaciously destroy tumors. The inhibition of enzymatic activity of COX and generation of O2(-•) by HF-LPLI in vivo were also detected.

INNOVATION

It is the first time that the mechanism involved in the interaction between light and its photoacceptor under HF-LPLI treatment is clarified. Our results clearly indicate that HF-LPLI initiates its effects via targeted COX photoinactivation and that the tumor-killing efficacy is dependent of the subsequent mitochondrial O2(-•) burst via ETC.

CONCLUSION

Based on both in vitro and in vivo results, we conclude that HF-LPLI can selectively photoinactivate respiratory chain oxidase to trigger a fatal mitochondrial O2(-•) burst, producing oxidative damage on cancer cells. This study opens up the possibilities of applications of HF-LPLI as a mitochondria-targeting cancer phototherapy.

Macrophage migration inhibitory factor is a possible candidate for the induction of microalbuminuria in diabetic db/db mice

Preventing the onset of microalbuminuria in diabetic nephropathy is a problem that needs urgent rectification. The use of a mouse model for diabetes is vital in this regard. For example, db/db mice exhibit defects in the leptin receptor Ob-Rb sub-type, while the ob/ob strain exhibits defects in the leptin ligand. These mouse strains demonstrate type 2 diabetes, either with or without microalbuminuria, respectively. The purpose of the present study was to use DNA microarray technology to screen for the gene responsible for the onset of diabetic microalbuminuria. Using Affymetrix Mouse Gene ST 1.0 arrays, microarray analysis was performed using total RNA from the kidneys of ob control, ob/ob, db/m, and db/db mice. Microarray and quantitative reverse transcription-polymerase chain reaction (RT-PCR) indicated that transcription of the macrophage migration inhibitory factor (MIF) gene was significantly enhanced in the kidneys of db/db mice. Western blotting showed that levels of MIF protein was enhanced in the kidneys of both diabetic db/db and ob/ob mice. On the other hand, elevation of urinary MIF excretion detected by enzyme-linked immunosorbent assay (ELISA) was only in db/db mice and preceded the onset of microalbuminuria. Immunofluorescence studies revealed that MIF was expressed in mouse kidney glomeruli. While MIF expression was enhanced in the diabetic kidneys of both mouse strains, the elevated secretion from db/db mouse kidneys may be responsible for initiating the onset of microalbuminuria in diabetic nephropathy.

HER2/ErbB2 activates HSF1 and thereby controls HSP90 clients including MIF in HER2-overexpressing breast cancer

Overexpression of the human epidermal growth factor receptor-2 (HER2) in breast cancer strongly correlates with aggressive tumors and poor prognosis. Recently, a positive correlation between HER2 and MIF (macrophage migration inhibitory factor, a tumor-promoting protein and heat-shock protein 90 (HSP90) client) protein levels was shown in cancer cells. However, the underlying mechanistic link remained unknown. Here we show that overexpressed HER2 constitutively activates heat-shock factor 1 (HSF1), the master transcriptional regulator of the inducible proteotoxic stress response of heat-shock chaperones, including HSP90, and a crucial factor in initiation and maintenance of the malignant state. Inhibiting HER2 pharmacologically by Lapatinib (a dual HER2/epidermal growth factor receptor inhibitor) or CP724.714 (a specific HER2 inhibitor), or by knockdown via siRNA leads to inhibition of phosphoactivated Ser326 HSF1, and subsequently blocks the activity of the HSP90 chaperone machinery in HER2-overexpressing breast cancer lines. Consequently, HSP90 clients, including MIF, AKT, mutant p53 and HSF1 itself, become destabilized, which in turn inhibits tumor proliferation. Mechanistically, HER2 signals via the phosphoinositide-3-kinase (PI3K)–AKT– mammalian target of rapamycin (mTOR) axis to induce activated pSer326 HSF1. Heat-shock stress experiments confirm this functional link between HER2 and HSF1, as HER2 (and PI3K) inhibition attenuate the HSF1-mediated heat-shock response. Importantly, we confirmed this axis in vivo. In the mouse model of HER2-driven breast cancer, ErbB2 inhibition by Lapatinib strongly suppresses tumor progression, and this is associated with inactivation of the HSF1 pathway. Moreover, ErbB2-overexpressing cancer cells derived from a primary mouse ErbB2 tumor also show HSF1 inactivation and HSP90 client destabilization in response to ErbB2 inhibition. Furthermore, in HER2-positive human breast cancers HER2 levels strongly correlate with pSer326 HSF1 activity. Our results show for the first time that HER2/ErbB2 overexpression controls HSF1 activity, with subsequent stabilization of numerous tumor-promoting HSP90 clients such as MIF, AKT and HSF1 itself, thereby causing a robust promotion in tumor growth in HER2-positive breast cancer.

Hsp60 chaperonopathies and chaperonotherapy: targets and agents

INTRODUCTION

Hsp60 (Cpn60) assembles into a tetradecamer that interacts with the co-chaperonin Hsp10 (Cpn10) to assist client polypeptides to fold, but it also has other roles, including participation in pathogenic mechanisms.

AREA COVERED

Hsp60 chaperonopathies are pathological conditions, inherited or acquired, in which the chaperone plays a determinant etiologic-pathogenic role. These diseases justify selection of Hsp60 as a target for developing agents that interfere with its pathogenic effects. We provide information on how to proceed.

EXPERT OPINION

The information available encourages the development of ways to improve Hsp60 activity (positive chaperonotherapy) when deficient or to block it (negative chaperonotherapy) when pathogenic. Many questions are still unanswered and obstacles are obvious. More information is needed to establish when and why autologous Hsp60 becomes a pathogenic autoantigen, or induces cytokine formation and inflammation, or favors carcinogenesis. Clarification of these points will take considerable time. However, analysis of the Hsp60 molecule and a search for active compounds aimed at structural sites that will affect its functioning should continue without interruption. No doubt that some of these compounds will offer therapeutic hopes and will also be instrumental for dissecting structure-function relationships at the biochemical and biological (using animal models and cultured cells) levels.

Fermentation and proteome profiles of Lactobacillus plantarum strains during growth under food-like conditions

This study aimed at investigating the proteomic adaptation of Lactobacillus plantarum strains. Cultivation of L. plantarum strains under food-like conditions (wheat flour hydrolyzed, whey milk, tomato juice) affected some metabolic traits (e.g., consumption of carbohydrates and synthesis of organic acids) compared to de Man, Rogosa and Sharpe (MRS) broth. The analysis of the fermentation profile showed that the highest number of carbon sources metabolized by L. plantarum strains was found using cells cultivated in media containing low concentration of glucose or no glucose at all. The proteomic maps of the strains were comparatively determined after growth on MRS broth and under food-like conditions. The amount of proteins depended on strain and, especially, on culture conditions. Proteins showing decreased or increased amounts under food-like conditions were identified using MALDI-TOF-MS/MS or LC-nano-ESI-MS/MS. Changes of the proteome concerned proteins that are involved in carbohydrate transport and metabolism, energy metabolism, Sec-dependent secretion system, stress response, nucleotide metabolism, regulation of nitrogen metabolism, and protein biosynthesis. A catabolic repression by glucose on carbohydrate transport and metabolism was also found. The characterization of the proteomes in response to changing environmental conditions could be useful to get L. plantarum strains adapted for specific applications.

BIOLOGICAL SIGNIFICANCE

Microbial cell performance during food biotechnological processes has become one of the greatest concerns all over the world. L. plantarum is a lactic acid bacterium with a large industrial application for fermented foods or functional foods (e.g., probiotics). The present study compared the fermentation and proteomic profiling of L. plantarum strains during growth under food-like conditions and under optimal laboratory conditions (MRS broth). This study provides specific mechanisms of proteomic adaptation involved in the microbial performances (carbohydrates utilization, energy metabolism, stress resistance, etc.) affecting the main biotechnological tracts of L. plantarum strains. The finding of this study provides evidences that may be exploited to get strains adapted for specific applications in food biotechnology.

Use of fungal proteases and selected sourdough lactic acid bacteria for making wheat bread with an intermediate content of gluten

This study was aimed at combining the highest degradation of gluten during wheat flour fermentation with good structural and sensory features of the related bread. As estimated by R5-ELISA, the degree of degradation of immune reactive gluten was ca. 28%. Two-dimensional electrophoresis and RP-FPLC analyses showed marked variations of the protein fractions compared to the untreated flour. The comparison was also extended to in vitro effect of the peptic/tryptic-digests towards K562 and T84 cells. The flour with the intermediate content of gluten (ICG) was used for bread making, and compared to whole gluten (WG) bread. The chemical, structural and sensory features of the ICG bread approached those of the bread made with WG flour. The protein digestibility of the ICG bread was higher than that from WG flour. Also the nutritional quality, as estimated by different indexes, was the highest for ICG bread.

Metabolic alterations in mammary cancer prevention by withaferin A in a clinically relevant mouse model

BACKGROUND

Efficacy of withaferin A (WA), an Ayurvedic medicine constituent, for prevention of mammary cancer and its associated mechanisms were investigated using mouse mammary tumor virus-neu (MMTV-neu) transgenic model.

METHODS

Incidence and burden of mammary cancer and pulmonary metastasis were scored in female MMTV-neu mice after 28 weeks of intraperitoneal administration with 100 µg WA (three times/week) (n = 32) or vehicle (n = 29). Mechanisms underlying mammary cancer prevention by WA were investigated by determination of tumor cell proliferation, apoptosis, metabolomics, and proteomics using plasma and/or tumor tissues. Spectrophotometric assays were performed to determine activities of complex III and complex IV. All statistical tests were two-sided.

RESULTS

WA administration resulted in a statistically significant decrease in macroscopic mammary tumor size, microscopic mammary tumor area, and the incidence of pulmonary metastasis. For example, the mean area of invasive cancer was lower by 95.14% in the WA treatment group compared with the control group (mean = 3.10 vs 63.77 mm2, respectively; difference = -60.67 mm2; 95% confidence interval = -122.50 to 1.13 mm2; P = .0536). Mammary cancer prevention by WA treatment was associated with increased apoptosis, inhibition of complex III activity, and reduced levels of glycolysis intermediates. Proteomics confirmed downregulation of many glycolysis-related proteins in the tumor of WA-treated mice compared with control, including M2-type pyruvate kinase, phospho glycerate kinase, and fructose-bisphosphate aldolase A isoform 2.

CONCLUSIONS

This study reveals suppression of glycolysis in WA-mediated mammary cancer prevention in a clinically relevant mouse model.

Extracellular heat shock protein A9 is a novel interaction partner of podoplanin in oral squamous cell carcinoma cells

In previous studies, we have shown several lines of evidence that podoplanin (PDPN) plays an important role in cell adhesion via its association with extracellular components in neoplastic conditions, though there has been no trial to search for PDPN-interaction molecules in the extracellular milieu. To screen for those molecules, we performed proteomics-based analysis using liquid chromatography-tandem mass spectrometry followed by co-immunoprecipitation for PDPN in ZK-1, an oral squamous cell carcinoma (SCC) cell system whose cell membrane molecules were cross-linked with each other in their extracellular compartments, and we identified heat shock protein (HSP) A9 as one of the extracellular PDPN bound molecules. Effects of transient PDPN knockdown by siRNA in ZK-1 were also comparatively examined for cellular behaviors in terms of HSPA9 expression and secretion. Finally, HSPA9 expression modes were immunohistochemically visualized in oral SCC tissue specimens. HSPA9 was secreted from ZK-1 cells, and the expression and secretion levels of HSPA9 gene and protein were well coordinated with those of PDPN. Immunohistochemically, HSPA9 and PDPN were co-localized in ZK-1 cells and oral SCC foci, especially in the peripheral zone. In conclusion, the results indicate that HSPA9 secreted by oral SCC cells interacts with PDPN on their cell surface in an autocrine manner and regulates their growth and invasiveness.

Effects of the peptide pheromone plantaricin A and cocultivation with Lactobacillus sanfranciscensis DPPMA174 on the exoproteome and the adhesion capacity of Lactobacillus plantarum DC400

This study aimed at investigating the extracellular and cell wall-associated proteins (exoproteome) of Lactobacillus plantarum DC400 when cultivated on modified chemically defined medium (CDM) supplemented with the chemically synthesized pheromone plantaricin A (PlnA) or cocultured with L. plantarum DPPMA20 or Lactobacillus sanfranciscensis DPPMA174. Compared to monoculture, two-dimensional gel electrophoresis (2-DE) analysis showed that the exoproteome of L. plantarum DC400 was affected by PlnA and cocultivation with strains DPPMA20 and, especially, DPPMA174. The highest similarity of the 2-DE maps was found between DC400 cells cultivated in monoculture and in coculture with strain DPPMA20. Almost all extracellular proteins (22 spots) and cell wall-associated proteins (40 spots) which showed decreased or increased levels of synthesis during growth in CDM supplemented with PlnA and/or in coculture with strain DPPMA20 or DPPMA174 were identified. On the basis of the sequences in the Kyoto Encyclopedia of Genes and Genomes database, changes to the exoproteome concerned proteins involved in quorum sensing (QS), the transport system, stress response, carbohydrate metabolism and glycolysis, oxidation/reduction processes, the proteolytic system, amino acid metabolism, cell wall and catabolic processes, and cell shape, growth, and division. Cultivation with PlnA and cocultivation with strains DPPMA20 and, especially, DPMMA174 markedly increased the capacity of L. plantarum DC400 to form biofilms, to adhere to human Caco-2 cells, and to prevent the adhesion of potential intestinal pathogens. These phenotypic traits were in part related to oversynthesized moonlighting proteins (e.g., DnaK and GroEL, pyruvate kinase, enolase, and glyceraldehyde-3-phosphate dehydrogenase) in response to QS mechanisms and interaction with L. plantarum DPPMA20 and, especially, L. sanfranciscensis DPPMA174.

Calreticulin and cancer

Calreticulin (CRT) as a multi-functional endoplasmic reticulum protein is involved in a spectrum of cellular processes which ranges from calcium homeostasis and chaperoning to cell adhesion and finally malignant formation and progression. Previous studies have shown a contributing role for CRT in a range of different cancers. This present review will focus on the possible roles of CRT in the progression of malignant proliferation and the mechanisms involved in its contribution to cancer invasion.

Proteomic analysis of breast cancer tissues to identify biomarker candidates by gel-assisted digestion and label-free quantification methods using LC-MS/MS

This study presents a proteomic method that differentiates between matched normal and breast tumor tissues from ductal carcinoma in situ (DCIS) and invasive carcinoma from Korean women, to identify biomarker candidates and to understand pathogenesis of breast cancer in protein level. Proteins from tissues obtained by biopsy were extracted by RIPA buffer, digested by the gel-assisted method, and analyzed by nano-UPLC-MS/MS. From proteomic analysis based on label-free quantitation strategy, a non-redundant list of 298 proteins was identified from the normal and tumor tissues, and 244 proteins were quantified using IDEAL-Q software. Hierarchical clustering analysis showed two patterns classified as two groups, invasive carcinoma and DCIS, suggesting a difference between two carcinoma at the protein expression level as expected. Differentially expressed proteins in tumor tissues compared to the corresponding normal tissues were related to three biological pathways: antigen-processing and presentation, glycolysis/gluconeogenesis, and complement and coagulation cascades. Among them, the up-regulation of calreticulin (CRT) and protein disulfide isomerase A3 (PDIA3) was confirmed by Western blot analysis. In conclusion, this study showed the possibility of identifying biomarker candidates for breast cancer using tissues and might help to understand the pathophysiology of this cancer at the protein level.