The mitochondrial protein C1qbp promotes cell proliferation, migration and resistance to cell death

Double-Edged Sword: Exploring the Mitochondria-Complement Bidirectional Connection in Cellular Response and Disease

Mitochondria serve an ultimate purpose that seeks to balance the life and death of cells, a role that extends well beyond the tissue and organ systems to impact not only normal physiology but also the pathogenesis of diverse diseases. Theorized to have originated from ancient proto-bacteria, mitochondria share similarities with bacterial cells, including their own circular DNA, double-membrane structures, and fission dynamics. It is no surprise, then, that mitochondria interact with a bacterium-targeting immune pathway known as a complement system. The complement system is an ancient and sophisticated arm of the immune response that serves as the body's first line of defense against microbial invaders. It operates through a complex cascade of protein activations, rapidly identifying and neutralizing pathogens, and even aiding in the clearance of damaged cells and immune complexes. This dynamic system, intertwining innate and adaptive immunity, holds secrets to understanding numerous diseases. In this review, we explore the bidirectional interplay between mitochondrial dysfunction and the complement system through the release of mitochondrial damage-associated molecular patterns. Additionally, we explore several mitochondria- and complement-related diseases and the potential for new therapeutic strategies.

Integrative analysis of proteomics and lipidomic profiles reveal the fat deposition and meat quality in Duroc × Guangdong small spotted pig

Introduction

This study aims to explore the important factors affecting the characteristics of different parts of pork.

Methods

Lipidomics and proteomics methods were used to analyze DAL (differential lipids) and DAPs (differential proteins) in five different parts (longissimus dorsi, belly meat, loin, forelegs and buttocks) of Duhua pig (Duroc × Guangdong small spotted pig), to identify potential pathways affecting meat quality, investigating fat deposition in pork and its lipid-protein interactions.

Results

The results show that TG (triglyceride) is the lipid subclass with the highest proportion in muscle, and the pathway with the most significantly enriched lipids is GP. DAP clustered on several GO terms closely related to lipid metabolism and lipogenesis (lipid binding, lipid metabolism, lipid transport, and lipid regulation). In KEGG analysis, there are two main DAP aggregation pathways related to lipid metabolism, namely Fatty acid degradation and oxidative phosphorylation. In PPI analysis, we screened out 31 core proteins, among which NDUFA6, NDUFA9 and ACO2 are the most critical.

Discussion

PC (phosphatidylcholine) is regulated by SNX5, THBS1, ANXA7, TPP1, CAVIN2, and VDAC2 in the phospholipid binding pathway. TG is regulated by AUH/HADH/ACADM/ACADL/HADHA in the lipid oxidation and lipid modification pathways. Potential biomarkers are rich in SFA, MUFA and PUFA respectively, the amounts of SFA, MUFA and PUFA in the lipid measurement results are consistent with the up- and down-regulation of potential biomarker lipids. This study clarified the differences in protein and lipid compositions in different parts of Duhua pigs and provided data support for revealing the interactions between pork lipids and proteins. These findings provide contributions to the study of intramuscular fat deposition in pork from a genetic and nutritional perspective.

Inhibition of Multifunctional Protein p32/C1QBP Promotes Cytostatic Effects in Colon Cancer Cells by Altering Mitogenic Signaling Pathways and Promoting Mitochondrial Damage

The protein p32 (C1QBP) is a multifunctional and multicompartmental homotrimer that is overexpressed in many cancer types, including colon cancer. High expression levels of C1QBP are negatively correlated with the survival of patients. Previously, we demonstrated that C1QBP is an essential promoter of migration, chemoresistance, clonogenic, and tumorigenic capacity in colon cancer cells. However, the mechanisms underlying these functions and the effects of specific C1QBP protein inhibitors remain unexplored. Here, we show that the specific pharmacological inhibition of C1QBP with the small molecule M36 significantly decreased the viability rate, clonogenic capacity, and proliferation rate of different colon cancer cell lines in a dose-dependent manner. The effects of the inhibitor of C1QBP were cytostatic and non-cytotoxic, inducing a decreased activation rate of critical pro-malignant and mitogenic cellular pathways such as Akt-mTOR and MAPK in RKO colon cancer cells. Additionally, treatment with M36 significantly affected the mitochondrial integrity and dynamics of malignant cells, indicating that p32/C1QBP plays an essential role in maintaining mitochondrial homeostasis. Altogether, our results reinforce that C1QBP is an important oncogene target and that M36 may be a promising therapeutic drug for the treatment of colon cancer.

SUZ domain-containing proteins have multiple effects on nonsense-mediated decay target transcripts

Many transcripts are targeted by nonsense-mediated decay (NMD), leading to their degradation and the inhibition of their translation. We found that the protein SUZ domain-containing protein 1 (SZRD1) interacts with the key NMD factor up-frameshift 1. When recruited to NMD-sensitive reporter gene transcripts, SZRD1 increased protein production, at least in part, by relieving translational inhibition. The conserved SUZ domain in SZRD1 was required for this effect. The SUZ domain is present in only three other human proteins besides SZRD1: R3H domain-containing protein 1 and 2 (R3HDM1, R3HDM2) and cAMP-regulated phosphoprotein 21 (ARPP21). We found that ARPP21, similarly to SZRD1, can increase protein production from NMD-sensitive reporter transcripts in an SUZ domain-dependent manner. This indicated that the SUZ domain-containing proteins could prevent translational inhibition of transcripts targeted by NMD. Consistent with the idea that SZRD1 mainly prevents translational inhibition, we did not observe a systematic decrease in the abundance of NMD targets when we knocked down SZRD1. Surprisingly, knockdown of SZRD1 in two different cell lines led to reduced levels of the NMD component UPF3B, which was accompanied by increased levels in a subset of NMD targets. This suggests that SZRD1 is required to maintain normal UPF3B levels and indicates that the effect of SZRD1 on NMD targets is not limited to a relief from translational inhibition. Overall, our study reveals that human SUZ domain-containing proteins play a complex role in regulating protein output from transcripts targeted by NMD.

Single-cell analysis of cellular heterogeneity and interactions in the ischemia-reperfusion injured mouse intestine

Nine major cell populations among 46,716 cells were identified in mouse intestinal ischemia‒reperfusion (II/R) injury by single-cell RNA sequencing. For enterocyte cells, 11 subclusters were found, in which enterocyte cluster 1 (EC1), enterocyte cluster 3 (EC3), and enterocyte cluster 8 (EC8) were newly discovered cells in ischemia 45 min/reperfusion 720 min (I 45 min/R 720 min) group. EC1 and EC3 played roles in digestion and absorption, and EC8 played a role in cell junctions. For TA cells, after ischemia 45 min/reperfusion 90 min (I 45 min/R 90 min), many TA cells at the stage of proliferation were identified. For Paneth cells, Paneth cluster 3 was observed in the resting state of normal jejunum. After I 45 min/R 90 min, three new subsets were found, in which Paneth cluster 1 had good antigen presentation activity. The main functions of goblet cells were to synthesize and secrete mucus, and a novel subcluster (goblet cluster 5) with highly proliferative ability was discovered in I 45 min/R 90 min group. As a major part of immune system, the changes in T cells with important roles were clarified. Notably, enterocyte cells secreted Guca2b to interact with Gucy2c receptor on the membranes of stem cells, TA cells, Paneth cells, and goblet cells to elicit intercellular communication. One marker known as glutathione S-transferase mu 3 (GSTM3) affected intestinal mucosal barrier function by adjusting mitogen-activated protein kinases (MAPK) signaling during II/R injury. The data on the heterogeneity of intestinal cells, cellular communication and the mechanism of GSTM3 provide a cellular basis for treating II/R injury.

Genetic mutations affecting mitochondrial function in cancer drug resistance

Mitochondria are organelles that serve as a central hub for physiological processes in eukaryotes, including production of ATP, regulation of calcium dependent signaling, generation of ROS, and regulation of apoptosis. Cancer cells undergo metabolic reprogramming in an effort to support their increasing requirements for cell survival, growth, and proliferation, and mitochondria have primary roles in these processes. Because of their central function in survival of cancer cells and drug resistance, mitochondria are an important target in cancer therapy and many drugs targeting mitochondria that target the TCA cycle, apoptosis, metabolic pathway, and generation of ROS have been developed. Continued use of mitochondrial-targeting drugs can lead to resistance due to development of new somatic mutations. Use of drugs is limited due to these mutations, which have been detected in mitochondrial proteins. In this review, we will focus on genetic mutations in mitochondrial target proteins and their function in induction of drug-resistance.

Identification of Geometrical Features of Cell Surface Responsible for Cancer Aggressiveness: Machine Learning Analysis of Atomic Force Microscopy Images of Human Colorectal Epithelial Cells

It has been recently demonstrated that atomic force microscopy (AFM) allows for the rather precise identification of malignancy in bladder and cervical cells. Furthermore, an example of human colorectal epithelial cells imaged in AFM Ringing mode has demonstrated the ability to distinguish cells with varying cancer aggressiveness with the help of machine learning (ML). The previously used ML methods analyzed the entire cell image. The problem with such an approach is the lack of information about which features of the cell surface are associated with a high degree of aggressiveness of the cells. Here we suggest a machine-learning approach to overcome this problem. Our approach identifies specific geometrical regions on the cell surface that are critical for classifying cells as highly or lowly aggressive. Such localization gives a path to colocalize the newly identified features with possible clustering of specific molecules identified via standard bio-fluorescence imaging. The biological interpretation of the obtained information is discussed.

C1QBP Mediates Breast Cancer Cell Proliferation and Growth via Multiple Potential Signalling Pathways

Breast carcinoma is the most prevalent cancer in women globally, with complex genetic and molecular mechanisms that underlie its development and progression. Several challenges such as metastasis and drug resistance limit the prognosis of breast cancer, and hence a constant search for better treatment regimes, including novel molecular therapeutic targets is necessary. Complement component 1, q subcomponent binding protein (C1QBP), a promising molecular target, has been implicated in breast carcinogenesis. In this study, the role of C1QBP in breast cancer progression, in particular cancer cell growth, was determined in triple negative MDA-MB-231 breast cancer cells. Depletion of C1QBP decreased cell proliferation, whereas the opposite effect was observed when C1QBP was overexpressed in MDA-MB-231 cells. Furthermore, gene expression profiling and pathway analysis in C1QBP depleted cells revealed that C1QBP regulates several signaling pathways crucial for cell growth and survival. Taken together, these findings provide a deeper comprehension of the role of C1QBP in triple negative breast cancer, and could possibly pave the way for future advancement of C1QBP-targeted breast cancer therapy.

An approach to p32/gC1qR/HABP1: a multifunctional protein with an essential role in cancer

P32/gC1qR/HABP1 is a doughnut-shaped acidic protein, highly conserved in eukaryote evolution and ubiquitous in the organism. Although its canonical subcellular localization is the mitochondria, p32 can also be found in the cytosol, nucleus, cytoplasmic membrane, and it can be secreted. Therefore, it is considered a multicompartmental protein. P32 can interact with many physiologically divergent ligands in each subcellular location and modulate their functions. The main ligands are C1q, hyaluronic acid, calreticulin, CD44, integrins, PKC, splicing factor ASF/SF2, and several microbial proteins. Among the functions in which p32 participates are mitochondrial metabolism and dynamics, apoptosis, splicing, immune response, inflammation, and modulates several cell signaling pathways. Notably, p32 is overexpressed in a significant number of epithelial tumors, where its expression level negatively correlates with patient survival. Several studies of gain and/or loss of function in cancer cells have demonstrated that p32 is a promoter of malignant hallmarks such as proliferation, cell survival, chemoresistance, angiogenesis, immunoregulation, migration, invasion, and metastasis. All of this strongly suggests that p32 is a potential diagnostic molecule and therapeutic target in cancer. Indeed, preclinical advances have been made in developing therapeutic strategies using p32 as a target. They include tumor homing peptides, monoclonal antibodies, an intracellular inhibitor, a p32 peptide vaccine, and p32 CAR T cells. These advances are promising and will allow soon to include p32 as part of targeted cancer therapies.

p32 promotes melanoma progression and metastasis by targeting EMT markers, Akt/PKB pathway, and tumor microenvironment

Melanoma originates from melanin-producing cells called melanocytes. Melanoma poses a great risk because of its rapid ability to spread and invade new organs. Cellular metastasis involves alteration in the gene expression profile and their transformation from epithelial to mesenchymal state. Despite of several advances, metastatic melanoma being a key cause of therapy failure and mortality remains poorly understood. p32 has been found to be involved in various physiological and pathophysiological conditions. However, the role of p32 in melanoma progression and metastasis remains underexplored. Here, we identify the role of p32 in the malignancy of both murine and human melanoma. p32 knockdown leads to reduced cell proliferation, migration, and invasion in murine and human melanoma cells. Furthermore, p32 promotes in vitro tumorigenesis, inducing oncogenes and EMT markers. Mechanistically, we show p32 regulates tumorigenic and metastatic properties through the Akt/PKB signaling pathway in both murine and human melanoma. Furthermore, p32 silencing attenuates melanoma tumor progression and lung metastasis in vivo, modulating the tumor microenvironment by inhibiting the angiogenesis, infiltration of macrophages, and leukocytes in mice. Taken together, our findings identify that p32 drives melanoma progression, metastasis, and regulates the tumor microenvironment. p32 can be a target of a novel therapeutic approach in the regulation of melanoma progression and metastasis.

Leaked Mitochondrial C1QBP Inhibits Activation of the DNA Sensor cGAS

Cytosolic DNA from pathogens activates the DNA sensor cyclic GMP-AMP (cGAMP) synthase (cGAS) that produces the second messenger, cGAMP. cGAMP triggers a signal cascade leading to type I IFN expression. Host DNA is normally restricted in the cellular compartments of the nucleus and mitochondria. Recent studies have shown that DNA virus infection triggers mitochondrial stress, leading to the release of mitochondrial DNA to the cytosol and activation of cGAS; however, the regulatory mechanism of mitochondrial DNA-mediated cGAS activation is not well elucidated. In this study, we analyzed cGAS protein interactome in mouse RAW264.7 macrophages and found that cGAS interacted with C1QBP. C1QBP predominantly localized in the mitochondria and leaked into the cytosol during DNA virus infection. The leaked C1QBP bound the NTase domain of cGAS and inhibited cGAS enzymatic activity in cells and in vitro. Overexpression of the cytosolic form of C1QBP inhibited cytosolic DNA-elicited innate immune responses and promoted HSV-1 infection. By contrast, deficiency of C1QBP led to the elevated innate immune responses and impaired HSV-1 infection. Taken together, our study suggests that C1QBP is a novel cGAS inhibitor hidden in the mitochondria.

Overexpression of Multifunctional Protein p32 Promotes a Malignant Phenotype in Colorectal Cancer Cells

p32 is a multifunctional and multicompartmental protein that has been found upregulated in numerous adenocarcinomas, including colorectal malignancy. High levels of p32 expression have been correlated with poor prognosis in colorectal cancer. However, the functions performed by p32 in colorectal cancer have not been characterized. Here we show that p32 is overexpressed in colorectal cancer cell lines compared to non-malignant colon cells. Colon cancer cells also display higher nuclear levels of p32 than nuclear levels found in non-malignant cells. Moreover, we demonstrate that p32 regulates the expression levels of genes tightly related to malignant phenotypes such as HAS-2 and PDCD4. Remarkably, we demonstrate that knockdown of p32 negatively affects Akt/mTOR signaling activation, inhibits the migration ability of colon malignant cells, and sensitizes them to cell death induced by oxidative stress and chemotherapeutic agents, but not to cell death induced by nutritional stress. In addition, knockdown of p32 significantly decreased clonogenic capacity and in vivo tumorigenesis in a xenograft mice model. Altogether, our results demonstrate that p32 is an important promoter of malignant phenotype in colorectal cancer cells, suggesting that it could be used as a therapeutic target in colorectal cancer treatment.

Affinity Purification-Mass Spectrometry Identifies a Novel Interaction between a Polerovirus and a Conserved Innate Immunity Aphid Protein that Regulates Transmission Efficiency

The vast majority of plant viruses are transmitted by insect vectors, with many crucial aspects of the transmission process being mediated by key protein-protein interactions. Still, very few vector proteins interacting with viruses have been identified and functionally characterized. Potato leafroll virus (PLRV) is transmitted most efficiently by Myzus persicae, the green peach aphid, in a circulative, non-propagative manner. Using affinity purification coupled to high-resolution mass spectrometry (AP-MS), we identified 11 proteins from M. persicaedisplaying a high probability of interaction with PLRV and an additional 23 vector proteins with medium confidence interaction scores. Three of these aphid proteins were confirmed to directly interact with the structural proteins of PLRV and other luteovirid species via yeast two-hybrid. Immunolocalization of one of these direct PLRV-interacting proteins, an orthologue of the human innate immunity protein complement component 1 Q subcomponent-binding protein (C1QBP), shows that MpC1QBP partially co-localizes with PLRV in cytoplasmic puncta and along the periphery of aphid gut epithelial cells. Artificial diet delivery to aphids of a chemical inhibitor of C1QBP leads to increased PLRV acquisition by aphids and subsequently increased titer in inoculated plants, supporting a role for C1QBP in the acquisition and transmission efficiency of PLRV by M. persicae. This study presents the first use of AP-MS for the in vivo isolation of a functionally relevant insect vector-virus protein complex. MS data are available from ProteomeXchange.org using the project identifier PXD022167.

YbeY, éminence grise of ribosome biogenesis

YbeY is an ultraconserved small protein belonging to the unique heritage shared by most existing bacteria and eukaryotic organelles of bacterial origin, mitochondria and chloroplasts. Studied in more than a dozen of evolutionarily distant species, YbeY is invariably critical for cellular physiology. However, the exact mechanisms by which it exerts such penetrating influence are not completely understood. In this review, we attempt a transversal analysis of the current knowledge about YbeY, based on genetic, structural, and biochemical data from a wide variety of models. We propose that YbeY, in association with the ribosomal protein uS11 and the assembly GTPase Era, plays a critical role in the biogenesis of the small ribosomal subunit, and more specifically its platform region, in diverse genetic systems of bacterial type.

Heterozygous P32/C1QBP/HABP1 Polymorphism rs56014026 Reduces Mitochondrial Oxidative Phosphorylation and Is Expressed in Low-grade Colorectal Carcinomas

Rapid proliferation of cancer cells is enabled by favoring aerobic glycolysis over mitochondrial oxidative phosphorylation (OXPHOS). P32 (C1QBP/gC1qR) is essential for mitochondrial protein translation and thus indispensable for OXPHOS activity. It is ubiquitously expressed and directed to the mitochondrial matrix in almost all cell types with an excessive up-regulation of p32 expression reported for tumor tissues. We recently demonstrated high levels of non-mitochondrial p32 to be associated with high-grade colorectal carcinoma. Mutations in human p32 are likely to disrupt proper mitochondrial function giving rise to various diseases including cancer. Hence, we aimed to investigate the impact of the most common single nucleotide polymorphism (SNP) rs56014026 in the coding sequence of p32 on tumor cell metabolism. In silico homology modeling of the resulting p.Thr130Met mutated p32 revealed that the single amino acid substitution potentially induces a strong conformational change in the protein, mainly affecting the mitochondrial targeting sequence (MTS). In vitro experiments confirmed an impaired mitochondrial import of mutated p32-T130M, resulting in reduced OXPHOS activity and a shift towards a low metabolic phenotype. Overexpression of p32-T130M maintained terminal differentiation of a goblet cell-like colorectal cancer cell line compared to p32-wt without affecting cell proliferation. Sanger sequencing of tumor samples from 128 CRC patients identified the heterozygous SNP rs56014026 in two well-differentiated, low proliferating adenocarcinomas, supporting our in vitro data. Together, the SNP rs56014026 reduces metabolic activity and proliferation while promoting differentiation in tumor cells.

YBEY is an essential biogenesis factor for mitochondrial ribosomes

Ribosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3′-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter helps to properly incorporate uS11m into the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.

Anti gC1qR/p32/HABP1 Antibody Therapy Decreases Tumor Growth in an Orthotopic Murine Xenotransplant Model of Triple Negative Breast Cancer

gC1qR is highly expressed in breast cancer and plays a role in cancer cell proliferation. This study explored therapy with gC1qR monoclonal antibody 60.11, directed against the C1q binding domain of gC1qR, in a murine orthotopic xenotransplant model of triple negative breast cancer. MDA231 breast cancer cells were injected into the mammary fat pad of athymic nu/nu female mice. Mice were segregated into three groups (n = 5, each) and treated with the vehicle (group 1) or gC1qR antibody 60.11 (100 mg/kg) twice weekly, starting at day 3 post-implantation (group 2) or when the tumor volume reached 100 mm³ (group 3). At study termination (d = 35), the average tumor volume in the control group measured 895 ± 143 mm³, compared to 401 ± 48 mm³ and 701 ± 100 mm³ in groups 2 and 3, respectively (p < 0.05). Immunohistochemical staining of excised tumors revealed increased apoptosis (caspase 3 and TUNEL staining) in 60.11-treated mice compared to controls, and decreased angiogenesis (CD31 staining). Slightly decreased white blood cell counts were noted in 60.11-treated mice. Otherwise, no overt toxicities were observed. These data are the first to demonstrate an in vivo anti-tumor effect of 60.11 therapy in a mouse model of triple negative breast cancer.

Curcumin induces chemosensitization to doxorubicin in Duke's type B coloadenocarcinoma cell line

Cancer cells require higher levels of ATP for their sustained growth, proliferation, and chemoresistance. Mitochondrial matrix protein, C1qbp is upregulated in colon cancer cell lines. It protects the mitochondria from oxidative stress, by inhibiting the Membrane Permeability Transition (MPT) pore and providing uninterrupted synthesis of ATP. This intracellular interaction of C1qbp could be involved in chemoresistance development. Natural chemosensitizing agent, curcumin has been used in the treatment of multiple cancers. In this current study, we elucidate the role of C1qbp during curcumin induced chemosensitization to doxorubicin resistant colon cancer cells. The possible interaction between C1qbp and curcumin was determined using bioinformatics tools-AutoDock, SYBYL, and PyMol. Intracellular doxorubicin accumulation by fluorimetry and dead cell count was carried out to determine development of chemoresistance. Effect of curcumin treatment and cytotoxicity was measured by MTT and lactate dehydrogenase release. Morphological analysis by phase contrast microscopy and colony forming ability by colonogenic assay were also performed. In addition, Cox-2 could mediate P-glycoprotein upregulation via phosphorylation of c-Jun. Thus, the gene level expression of P-glycoprotein and Cox-2 was also investigated using PCR. Through molecular docking we identified possible interaction between curcumin and C1qbp. We observed development of chemoresistance upon 6th day treatment. Concentration dependent alleviation of chemoresistance development by curcumin was confirmed and was found to reduce gene level expression of P-glycoprotein and Cox-2. Hence, curcumin could interact directly with C1qbp protein and this interaction could contribute to the chemosensiting effect to doxorubicin in colon cancer cells.

Complement's favourite organelle-Mitochondria?

The complement system, well known for its central role in innate immunity, is currently emerging as an unexpected, cell‐autonomous, orchestrator of normal cell physiology. Specifically, an intracellularly active complement system—the complosome—controls key pathways of normal cell metabolism during immune cell homeostasis and effector function. So far, we know little about the exact structure and localization of intracellular complement components within and among cells. A common scheme, however, is that they operate in crosstalk with other intracellular immune sensors, such as inflammasomes, and that they impact on the activity of key subcellular compartments. Among cell compartments, mitochondria appear to have built a particularly early and strong relationship with the complosome and extracellularly active complement—not surprising in view of the strong impact of the complosome on metabolism. In this review, we will hence summarize the current knowledge about the close complosome–mitochondria relationship and also discuss key questions surrounding this novel research area.

Identification of the hyaluronic acid pathway as a therapeutic target for facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is linked to epigenetic derepression of the germline/embryonic transcription factor DUX4 in skeletal muscle. However, the etiology of muscle pathology is not fully understood, as DUX4 misexpression is not tightly correlated with disease severity. Using a DUX4-inducible cell model, we show that multiple DUX4-induced molecular pathologies that have been observed in patient-derived disease models are mediated by the signaling molecule hyaluronic acid (HA), which accumulates following DUX4 induction. These pathologies include formation of RNA granules, FUS aggregation, DNA damage, caspase activation, and cell death. We also observe previously unidentified pathologies including mislocalization of mitochondria and the DUX4- and HA-binding protein C1QBP. These pathologies are prevented by 4-methylumbelliferone, an inhibitor of HA biosynthesis. Critically, 4-methylumbelliferone does not disrupt DUX4-C1QBP binding and has only a limited effect on DUX4 transcriptional activity, establishing that HA signaling has a central function in pathology and is a target for FSHD therapeutics.

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients’ PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa

Globular C1q Receptor (gC1qR/p32/HABP1) Is Overexpressed in Malignant Pleural Mesothelioma and Is Associated With Increased Survival in Surgical Patients Treated With Chemotherapy

Introduction: Globular C1q receptor (gC1qR/p32/HABP1) is overexpressed in a variety of cancers, particularly adenocarcinomas. This study investigated gC1qR expression in malignant pleural mesothelioma (MPM) and its pathophysiologic correlates in a surgical patient cohort.

Methods: Tissue microarrays comprising 6 tumoral and 3 stromal cores from 265 patients with MPM (216 epithelioid, 26 biphasic, and 23 sarcomatoid; 1989–2010) were investigated by immunohistochemistry for gC1qR expression (intensity and distribution by H-score, range 0–300), and immune cell infiltration. Overall survival (OS) was analyzed by the Kaplan-Meier method (high vs. low gC1qR expression delineated by median score) in the whole cohort and by neoadjuvant chemotherapy (NAC) status. Multivariable Cox analysis included stage, chemotherapy, and immune cell infiltration.

Results: gC1qR was overexpressed in all histological types of MPMs (263/265, 99.2%) compared to normal pleura. In epithelioid MPM, high gC1qR expression was associated with better OS (median 25 vs. 11 months; p = 0.020) among NAC patients, and among patients without NAC (No-NAC) but who received post-operative chemotherapy (median OS 38 vs. 19 months; p = 0.0007). In multivariable analysis, high gC1qR expression was an independent factor for improved OS in patients treated with NAC. In the No-NAC cohort, high gC1qR expression correlated with lower tumor stage. Moreover, the influence of Ki67 and CD4 T-cell infiltration on OS were more pronounced among patients with high gC1qR expression.

Conclusion: This is the first description of gC1qR expression in MPM. The data identify gC1qR as a potential new prognostic factor in patients treated with surgery and chemotherapy.

Protein profiling of SH-SY5Y neuroblastoma cells: The effect of rhein

4,5-Dihydroxyanthraquinone-2-carboxylic acid (Rhein) has been shown to have various physiological and pharmacological properties including anticancer activity and modulatory effects on bioenergetics. In this study, we explored the impact of rhein on protein profiling of undifferentiated (UC) and differentiated (DC) SH-SY5Y cells. Besides that, the cellular morphology and expression of differentiation markers were investigated to determine the effect of rhein on retinoic acidinduced neuronal cell differentiation. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ ionization-time-of-flight mass spectrometry we evaluated the changes in the proteome of both UC and DC SH-SY5Y cells after 24 h treatment with rhein. Validation of selected differentially expressed proteins and the assessment of neuronal differentiation markers were performed by western blotting. Proteomic analysis revealed significant changes in the abundance of 15 proteins linked to specific cellular processes such as cytoskeleton structure and regulation, mitochondrial function, energy metabolism, protein synthesis and neuronal plasticity. We also observed that the addition of rhein to the cultured cells during differentiation resulted in a significantly reduced neurite outgrowth and decreased expression of neuronal markers. These results indicate that rhein may strongly interfere with the differentiation process of SH-SY5Y neuroblastoma cells and is capable of inducing marked proteomic changes in these cells.

Clinical implications of a novel prognostic factor AIFM3 in breast cancer patients

Background

In a time of increasing concerns over personalized and precision treatment in breast cancer (BC), filtering prognostic factors attracts more attention. Apoptosis-Inducing Factor Mitochondrion-associated 3 (AIFM3) is widely expressed in various tissues and aberrantly expressed in several cancers. However, clinical implication of AIFM3 has not been reported in BC. The aim of the study is to investigate the crystal structure, clinical and prognostic implications of AIFM3 in BC.

Methods

AIFM3 expression in 151 BC samples were assessed by immunohistochemistry (IHC). The Cancer Genome Atlas (TCGA) and Kaplan-Meier survival analysis were used to demonstrate expression and survival of AIFM3 signature. Gene Set Enrichment Analysis (GSEA) was performed to investigate the mechanisms related to AIFM3 expression in BC.

Results

AIFM3 was significantly more expressed in breast cancer tissues than in normal tissues. AIFM3 expression had a significant association with tumor size, lymph node metastasis, TNM stage and molecular typing. Higher AIFM3 expression was related to a shorter overall survival (OS) and disease-free survival (DFS). Lymph node metastasis and TNM stage were independent factors of AIFM3 expression. The study presented the crystal structure of AIFM3 successfully and predicted several binding sites when AIFM3 bonded to PTPN12 by Molecular Operating Environment software (MOE).

Conclusions

AIFM3 might be a potential biomarker for predicting prognosis in BC, adding to growing evidence that AIFM3 might interact with PTPN12.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5659-4) contains supplementary material, which is available to authorized users.

Systematic Multiomics Analysis of Alterations in C1QBP mRNA Expression and Relevance for Clinical Outcomes in Cancers

C1QBP (Complement Component 1 Q Subcomponent-Binding Protein), a multicompartmental protein, participates in various cellular processes, including mRNA splicing, ribosome biogenesis, protein synthesis in mitochondria, apoptosis, transcriptional regulation, and infection processes of viruses. The correlation of C1QBP expression with patient survival and molecular function of C1QBP in relation to cancer progression has not been comprehensively studied. Therefore, we sought to systematically investigate the expression of C1QBP to evaluate the change of C1QBP expression and the relationship with patient survival and affected pathways in breast, lung, colon, and bladder cancers as well as lymphoma. Relative expression levels of C1QBP were analyzed using the Oncomine, Gene Expression Across Normal and Tumor Tissue (GENT), and The Cancer Genome Atlas (TCGA) databases. Mutations and copy number alterations in C1QBP were also analyzed using cBioPortal, and subsequently, the relationship between C1QBP expression and survival probability of cancer patients was explored using the PrognoScan database and the R2: Kaplan Meier Scanner. Additionally, the relative expression of C1QBP in other cancers, and correlation of C1QBP expression with patient survival were investigated. Gene ontology and pathway analysis of commonly differentially coexpressed genes with C1QBP in breast, lung, colon, and bladder cancers as well as lymphoma revealed the C1QBP-correlated pathways in these cancers. This data-driven study demonstrates the correlation of C1QBP expression with patient survival and identifies possible C1QBP-involved pathways, which may serve as targets of a novel therapeutic modality for various human cancers.

Phytanoyl-CoA 2-Hydroxylase-Interacting Protein-Like Gene Is a Therapeutic Target Gene for Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common primary CNS cancer and has a poor prognosis. This study searched for significant genes and the mechanisms involved in GBM. We used the Gene Expression Omnibus (GEO) to test the WHO normal and IV glioma database, used R tool to identify the significant gene, and finally, combined these with The Cancer Genome Atlas (TCGA) to verify the significant genes. Subsequently, we explored the biological mechanisms involved. Phytanoyl-CoA 2-hydroxylase-interacting protein-like gene (PHYHIPL) is downregulated in grade IV glioma (GBM). The downregulation of PHYHIPL in GBM is accompanied by poor overall survival in the TCGA database, which indicates that PHYHIPL is a protection gene in GBM development. Bioinformatics analysis shows that the poor prognosis with downregulated PHYHIPL may be the result of the TNF signaling pathway and the IL-17 signaling pathway, but good prognosis accompanied by upregulated PHYHIPL may be the result of retrograde endocannabinoid signaling and the cAMP signaling pathway. Protein-protein interactions (PPI) net indicated that PHYHIPL may play a vital role in cell metabolism, and we hypothesize that the downregulation mechanism may be the result of mutations of the ß-catenin gene and the endogenous siRNA, as shown in previous studies. PHYHIPL may be a target gene for the treatment and prognosis of GBM.

Import of Non-Coding RNAs into Human Mitochondria: A Critical Review and Emerging Approaches

Mitochondria harbor their own genetic system, yet critically depend on the import of a number of nuclear-encoded macromolecules to ensure their expression. In all eukaryotes, selected non-coding RNAs produced from the nuclear genome are partially redirected into the mitochondria, where they participate in gene expression. Therefore, the mitochondrial RNome represents an intricate mixture of the intrinsic transcriptome and the extrinsic RNA importome. In this review, we summarize and critically analyze data on the nuclear-encoded transcripts detected in human mitochondria and outline the proposed molecular mechanisms of their mitochondrial import. Special attention is given to the various experimental approaches used to study the mitochondrial RNome, including some recently developed genome-wide and in situ techniques.

Complement component 1q subcomponent binding protein in the brain of the rat

Complement component 1q subcomponent binding protein (C1qbp) is a multifunctional protein involved in immune response, energy homeostasis of cells as a plasma membrane receptor, and a nuclear, cytoplasmic or mitochondrial protein. Recent reports suggested its neuronal function, too, possibly in axon maintenance, synaptic function, and neuroplasticity. Therefore, we addressed to identify C1qbp in the rat brain using in situ hybridization histochemistry and immunolabelling at light and electron microscopic level. C1qbp has a topographical distribution in the brain established by the same pattern of C1qbp mRNA-expressing and protein-containing neurons with the highest abundance in the cerebral cortex, anterodorsal thalamic nucleus, hypothalamic paraventricular (PVN) and arcuate nuclei, spinal trigeminal nucleus. Double labelling of C1qbp with the neuronal marker NeuN, with the astrocyte marker S100, and the microglia marker Iba1 demonstrated the presence of C1qbp in neurons but not in glial cells in the normal brain, while C1qbp appeared in microglia following their activation induced by focal ischemic lesion. Only restricted neurons expressed C1qbp, for example, in the PVN, magnocellular neurons selectively contained C1qbp. Further double labelling by using the mitochondria marker Idh3a antibody suggested the mitochondrial localization of C1qbp in the brain, confirmed by correlated light and electron microscopy at 3 different brain regions. Post-embedding immunoelectron microscopy also suggested uneven C1qbp content of mitochondria in different brain areas but also heterogeneity within single neurons. These data suggest a specific function of C1qbp in the brain related to mitochondria, such as the regulation of local energy supply in neuronal cells.

High cytoplasm HABP1 expression as a predictor of poor survival and late tumor stage in pancreatic ductal adenocarcinoma patients

BACKGROUND

Hyaluronan-binding protein 1 (HABP1) overexpression has been confirmed in different malignancies and found to be strongly associated with tumor development and progression. The aim of the present study was to explore the impact of HABP1 in pancreatic ductal adenocarcinoma (PDAC) patients.

METHOD

HABP1 expression was evaluated in 89 PDAC specimens.

RESULTS

The expression of HABP1 was significantly higher in tumor tissues than that in adjacent normal tissues. High nucleus HABP1 expression and high cytoplasm HABP1 expression were both detected in PDAC tissues. Overall survival analysis by optical density showed that the mean survival was similar between patients with low and high optical density values of HABP1 expression (P = 0.312). The similar result was also found between patients with low-moderate or high nucleus HABP1 expression (P = 0.275). However, the mean survival was significantly poorer in patients with cytoplasm HABP1 overexpression (P < 0.001). High cytoplasm HABP1 expression was strongly correlated with late tumor stages, arterial involvement, lymph node metastasis and carbohydrate antigen 19-9 levels.

CONCLUSION

High cytoplasm HABP1 expression may prove to be a predictor of poor survival and late tumor stage in PDAC patients. HABP1 could serve as a promising biomarker to identify subsets of PDAC patients with high malignant clinical behavior.

Surpassing 10 000 identified and quantified proteins in a single run by optimizing current LC-MS instrumentation and data analysis strategy

Optimization of chromatography and data analysis resulted in more than 10 000 proteins in a single shot at a validated FDR of 1% (two-species test) and revealed deep insights into the testis cancer physiology.

Toxicoproteomic analysis of human lung epithelial cells exposed to steel industry ambient particulate matter (PM) reveals possible mechanism of PM related carcinogenesis

Toxicoproteomic analysis of steel industry ambient particulate matter (PM) that contain high concentrations of PAHs and metals was done by treating human lung cancer cell-line, A549 and the cell lysates were analysed using quantitative label-free nano LC-MS/MS. A total of 18,562 peptides representing 1576 proteins were identified and quantified, with 196 proteins had significantly altered expression in the treated cells. Enrichment analyses revealed that proteins associated to redox homeostsis, metabolism, and cellular energy generation were inhibited while, proteins related to DNA damage and repair and other stresses were over expressed. Altered activities of several tumor associated proteins were observed. Protein-protein interaction network and biological pathway analysis of these differentially expressed proteins were carried out to obtain a systems level view of proteome changes. Together it could be inferred that PM exposure induced oxidative stress which could have lead into DNA damage and tumor related changes. However, lowering of cellular metabolism, and energy production could reduce its ability to overcome these stress. This kind of disequilibrium between the DNA damage and ability of the cells to repair the DNA damage may lead into genomic instability that is capable of acting as the driving force during PM induced carcinogenesis.

Delineating the HMGB1 and HMGB2 interactome in prostate and ovary epithelial cells and its relationship with cancer

High Mobility Group B (HMGB) proteins are involved in cancer progression and in cellular responses to platinum compounds used in the chemotherapy of prostate and ovary cancer. Here we use affinity purification coupled to mass spectrometry (MS) and yeast two-hybrid (Y2H) screening to carry out an exhaustive study of HMGB1 and HMGB2 protein interactions in the context of prostate and ovary epithelia. We present a proteomic study of HMGB1 partners based on immunoprecipitation of HMGB1 from a non-cancerous prostate epithelial cell line. In addition, HMGB1 and HMGB2 were used as baits in yeast two-hybrid screening of libraries from prostate and ovary epithelial cell lines as well as from healthy ovary tissue. HMGB1 interacts with many nuclear proteins that control gene expression, but also with proteins that form part of the cytoskeleton, cell-adhesion structures and others involved in intracellular protein translocation, cellular migration, secretion, apoptosis and cell survival. HMGB2 interacts with proteins involved in apoptosis, cell motility and cellular proliferation. High confidence interactors, based on repeated identification in different cell types or in both MS and Y2H approaches, are discussed in relation to cancer. This study represents a useful resource for detailed investigation of the role of HMGB1 in cancer of epithelial origins, as well as potential alternative avenues of therapeutic intervention.

[Value of CHCHD2 as a potential marker of non-small cell lung cancer: analysis of 60 cases]

OBJECTIVE

To investigate the expression of CHCHD2, a potential tumor marker, in tumor and adjacent tissues from patients with non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemistry was used to detect the expression and location of CHCHD2 in the tumor tissues from 60 patients with NSCLC and 35 adjacent tissues to analyze the correlation of CHCHD2 expression with the clinicopathological variables and overall survival of the patients. The expression profile of CHCHD2 mRNA in NSCLC was analyzed using Oncomine database.

RESULTS

The positivity rate of CHCHD2 was significantly higher in the tumor tissues than in adjacent tissues in patients with NSCLC (75.0% vs 17.1%). CHCHD2 positivity in the tumor tissues was associated with lymph node metastasis, pathological TNM stage, and tumor grades but not with age, gender, or histological type of the tumors. Analysis using Oncomine database showed that CHCHD2 mRNA was expressed at significantly higher levels in NSCLC than in normal control group (P<0.05). Kaplan-Meier survival analysis showed that NSCLC patients with a positive expression of CHCHD2 had a significantly shorter overall survival time than those negative for CHCHD2 (P<0.05).

CONCLUSION

As a potential tumor marker, CHCHD2 over-expression plays a role in the occurrence and progression of NSCLC and promotes tumor invasion and metastasis, and can potentially serve as an indicator for early diagnosis and prognostic evaluation of NSCLC.

[Value of CHCHD2 as a potential marker of non-small cell lung cancer: analysis of 60 cases]

OBJECTIVE

To investigate the expression of CHCHD2, a potential tumor marker, in tumor and adjacent tissues from patients with non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemistry was used to detect the expression and location of CHCHD2 in the tumor tissues from 60 patients with NSCLC and 35 adjacent tissues to analyze the correlation of CHCHD2 expression with the clinicopathological variables and overall survival of the patients. The expression profile of CHCHD2 mRNA in NSCLC was analyzed using Oncomine database.

RESULTS

The positivity rate of CHCHD2 was significantly higher in the tumor tissues than in adjacent tissues in patients with NSCLC (75.0% vs 17.1%). CHCHD2 positivity in the tumor tissues was associated with lymph node metastasis, pathological TNM stage, and tumor grades but not with age, gender, or histological type of the tumors. Analysis using Oncomine database showed that CHCHD2 mRNA was expressed at significantly higher levels in NSCLC than in normal control group (P<0.05). Kaplan-Meier survival analysis showed that NSCLC patients with a positive expression of CHCHD2 had a significantly shorter overall survival time than those negative for CHCHD2 (P<0.05).

CONCLUSION

As a potential tumor marker, CHCHD2 over-expression plays a role in the occurrence and progression of NSCLC and promotes tumor invasion and metastasis, and can potentially serve as an indicator for early diagnosis and prognostic evaluation of NSCLC.

Long non-coding RNA RPAIN regulates the invasion and apoptosis of trophoblast cell lines via complement protein C1q

Long non-coding RNAs (lncRNAs) are key regulatory molecules that are involved in a variety of biological processes and human diseases. Their impact on early onset preeclampsia remains unclear. In this study, we tested the expression of RPAIN (transcript variant 12 of RPA interacting protein, a non-coding RNA, NR_027683.1) in placenta tissues derived from 25 pregnant women with PE and 15 healthy pregnant women using quantitative real-time PCR. The effect of RPAIN on trophoblast proliferation, invasion, and apoptosis and the underlying mechanisms were examined in trophoblast cell lines (HTR-8/SVneo). The results showed that RPAIN expression levels were significantly increased in early onset preeclamptic placentas compared to normal controls. The proliferation and invasive abilities of the trophoblast cells were significantly inhibited, and the apoptosis abilities of the trophoblast cells were significantly promoted when RPAIN was overexpressed. In addition, the overexpression of RPAIN inhibited the expression of complement protein C1q. Furthermore, C1q overexpression rescued the decreased cell invasion and enhanced cell apoptosis in RPAIN-overexpressing trophoblast cells. Our results suggest that increased RPAIN levels may contribute to the development of preeclampsia through regulating trophoblast invasion and apoptosis via C1q. Therefore, we proposed RPAIN as a novel lncRNA molecule, which might contribute to the development of PE (preeclampsia) and might compose a potential diagnostic and therapeutic target for this disease.

Decreased KPNB1 Expression is Induced by PLK1 Inhibition and Leads to Apoptosis in Lung Adenocarcinoma

Lung cancer is a major cause of death worldwide, with lung adenocarcinoma being the most frequently diagnosed subtype in Japan. Finding the target of an anticancer drug can improve lung adenocarcinoma treatments. Polo-like kinase 1 (PLK1) is an essential mitotic kinase in mitotic progression, and PLK1 inhibition induces cell cycle arrest and apoptosis in tumor cells. In addition, a variety of PLK1 inhibitors have been identified for cancer treatments. In this study, we looked for the target gene of the anticancer drug that has synergy with PLK1 inhibitors. We identified karyopherin beta 1 (KPNB1) as a possible target for lung adenocarcinoma treatment. We found that PLK1 inhibition decreased KPNB1 expression in lung adenocarcinoma cells and KPNB1 depletion inhibited cell proliferation via apoptosis. The same apoptosis signaling pathway may be activated because the expression of common apoptosis-related genes was decreased by PLK1 and KPNB1 silencing; however, the time course of cell growth inhibition was somewhat different. Cell cycle analysis showed that KPNB1 depletion increased the proportion of cells at the G0/G1 phase, although cells also accumulated at the G2/M phase in PLK1-depleted cells. Our findings suggest that decreased KPNB1 expression may be associated with the apoptosis induced by PLK1 inhibition.

A novel small molecule inhibitor of p32 mitochondrial protein overexpressed in glioma

BACKGROUND

The mitochondrial protein p32 is a validated therapeutic target of cancer overexpressed in glioma. Therapeutic targeting of p32 with monoclonal antibody or p32-binding LyP-1 tumor-homing peptide can limit tumor growth. However, these agents do not specifically target mitochondrial-localized p32 and would not readily cross the blood-brain barrier to target p32-overexpressing gliomas. Identifying small molecule inhibitors of p32 overexpressed in cancer is a more rational therapeutic strategy. Thus, in this study we employed a pharmacophore modeling strategy to identify small molecules that could bind and inhibit mitochondrial p32.

METHODS

A pharmacophore model of C1q and LyP-1 peptide association with p32 was used to screen a virtual compound library. A primary screening assay for inhibitors of p32 was developed to identify compounds that could rescue p32-dependent glutamine-addicted glioma cells from glutamine withdrawal. Inhibitors from this screen were analyzed for direct binding to p32 by fluorescence polarization assay and protein thermal shift. Affect of the p32 inhibitor on glioma cell proliferation was assessed by Alamar Blue assay, and affect on metabolism was examined by measuring lactate secretion.

RESULTS

Identification of a hit compound (M36) validates the pharmacophore model. M36 binds directly to p32 and inhibits LyP-1 tumor homing peptide association with p32 in vitro. M36 effectively inhibits the growth of p32 overexpressing glioma cells, and sensitizes the cells to glucose depletion.

CONCLUSIONS

This study demonstrates a novel screening strategy to identify potential inhibitors of mitochondrial p32 protein overexpressed in glioma. High throughput screening employing this strategy has potential to identify highly selective, potent, brain-penetrant small molecules amenable for further drug development.

HIV-1 Gp120 clade B/C induces a GRP78 driven cytoprotective mechanism in astrocytoma

HIV-1 clades are known to be one of the key factors implicated in modulating HIV-associated neurocognitive disorders. HIV-1 B and C clades account for the majority of HIV-1 infections, clade B being the most neuropathogenic. The mechanisms behind HIV-mediated neuropathogenesis remain the subject of active research. We hypothesized that HIV-1 gp120 clade B and C proteins may exert differential proliferation, cell survival and NeuroAIDS effects in human astrocytoma cells via the Unfolded Protein Response, an endoplasmic reticulum- based cytoprotective mechanism. The differential effect of gp120 clade B and C was evaluated using for the first time a Tandem Mass Tag isobaric labeling quantitative proteomic approach. Flow cytometry analyses were performed for cell cycle and cell death identification. Among the proteins differentiated by HIV-1 gp120 proteins figure cytoskeleton, oxidative stress, UPR markers and numerous glycolytic metabolism enzymes. Our results demonstrate that HIV-1 gp120 B induced migration, proliferative and protective responses granted by the expression of GRP78, while HIV-1 gp120 C induced the expression of key inflammatory and pro-apoptotic markers. These novel findings put forward the first evidence that GRP78 is a key player in HIV-1 clade B and C neuropathogenic discrepancies and can be used as a novel target for immunotherapies.

C1QBP is upregulated in colon cancer and binds to apolipoprotein A-I

The present study aimed to investigate the expression of complement component 1, q subcomponent-binding protein (C1QBP) in colon cancer cells, and identify proteins that interact with C1QBP. Total proteins were extracted from both the tumor and normal tissues of 22 patients with colon cancer and analyzed using liquid chromatography-mass spectrometry (LC-MS) to identify proteins that were differentially-expressed in tumor tissues. C1QBP overexpression was induced in 293T cells using a pFLAG-CMV2 expression vector. Overexpressed FLAG-tagged C1QBP protein was then immunoprecipitated using anti-FLAG antibodies and C1QBP-interacting proteins were screened using LC-MS analysis of the immunoprecipitates. The C1QBP-interacting proteins were confirmed using reverse-immunoprecipitation and the differential expression of C1QBP in tissues and cell lines was confirmed using western blot analysis. LC-MS analysis revealed that C1QBP exhibited a typical tumor expression pattern. Two immune-reactive signals (33 and 14 kDa) were detected in normal and tumor tissues from 19 patients. Furthermore, 14 kDa C1QBP protein was upregulated in the tumors of 15 patients. In total, 39 proteins were identified as candidate C1QBP-interacting proteins, and an interaction between C1QBP and apolipoprotein A-I was confirmed. The present study indicates that C1QBP is involved in colon cancer carcinogenesis, and that the mechanisms underlying the established anti-tumor properties of apolipoprotein A-I may include interacting with and inhibiting the activity of C1QBP.

Luteolin inhibits lung metastasis, cell migration, and viability of triple-negative breast cancer cells

Most breast cancer-related deaths from triple-negative breast cancer (TNBC) occur following metastasis of cancer cells and development of tumors at secondary sites. Because TNBCs lack the three receptors targeted by current chemotherapeutic regimens, they are typically treated with extremely aggressive and highly toxic non-targeted treatment strategies. Women with TNBC frequently develop metastatic lesions originating from drug-resistant residual cells and have poor prognosis. For this reason, novel therapeutic strategies that are safer and more effective are sought. Luteolin (LU) is a naturally occurring, non-toxic plant compound that has proven effective against several types of cancer. With this in mind, we conducted in vivo and in vitro studies to determine whether LU might suppress metastasis of TNBC. In an in vivo mouse metastasis model, LU suppressed metastasis of human MDA-MB-435 and MDA-MB-231 (4175) LM2 TNBC cells to the lungs. In in vitro assays, LU inhibited cell migration and viability of MDA-MB-435 and MDA-MB-231 (4175) LM2 cells. Further, LU induced apoptosis in MDA-MB-231 (4175) LM2 cells. Relatively low levels (10 µM) of LU significantly inhibited vascular endothelial growth factor (VEGF) secretion in MDA-MB-231 (4175) LM2 cells, suggesting that it has the ability to suppress a potent angiogenic and cell survival factor. In addition, migration of MDA-MB-231 (4175) LM2 cells was inhibited upon exposure to an antibody against the VEGF receptor, KDR, but not by exposure to a VEGF₁₆₅ antibody. Collectively, these data suggest that the anti-metastatic properties of LU may, in part, be due to its ability to block VEGF production and KDR-mediated activity, thereby inhibiting tumor cell migration. These studies suggest that LU deserves further investigation as a potential treatment option for women with TNBC.

Microarray analysis of differential gene expression profiles in blood cells of naturally BLV-infected and uninfected Holstein-Friesian cows

The aim of the present study was to examine gene expression changes in response to bovine leukemia virus (BLV) infection, in an effort to determine genes that take a part in molecular events leading to persistent lymphocytosis (PL), and to better define genes involved in host response to BLV infection. Using bovine 70-mer oligonucleotide spotted microarrays (BLOPlus) and qRT-PCR validation, we studied global gene expression profiles in blood cells in vivo of 12 naturally BLV-infected Polish Holstein cows, and 12 BLV non-infected controls of the same breed and reared in herds with high BLV seroprevalence. With an arbitrary cut-off value of 1.5-fold change in gene expression, we identified the down-regulation of 212 genes (M value ≤-0.585) and the up-regulation of 158 genes (M value of ≥0.585) at 1% false discovery rate in BLV-positive animals in comparison to the BLV-negative group. The gene set enrichment analysis demonstrated that the differentially expressed (DE) genes could be classified to diverse biological processes, including immune response of host blood cells. Interestingly, our data indicated the potential involvement of the innate immunity, including complement system activation, NK-cell cytotoxicity and TREM-1 signaling, during the BLV-induced pathogenesis. We showed the occurrence of numerous regulatory processes that are targeted by BLV-infection. We also suggest that a complex network of interrelated pathways is disturbed, causing the interruption of the control of B-cell proliferation and programmed cell death.

Proteomics Analysis Reveals Novel RASSF2 Interaction Partners

RASSF2 is a tumor suppressor that shares homology with other Ras-association domain (RASSF) family members. It is a powerful pro-apoptotic K-Ras effector that is frequently inactivated in many human tumors. The exact mechanism by which RASSF2 functions is not clearly defined, but it likely acts as a scaffolding protein, modulating the activity of other pro-apoptotic effectors, thereby regulating and integrating tumor suppressor pathways. However, only a limited number of RASSF2 interacting partners have been identified to date. We used a proteomics based approach to identify additional RASSF2 interactions, and thereby gain a better insight into the mechanism of action of RASSF2. We identified several proteins, including C1QBP, Vimentin, Protein phosphatase 1G and Ribonuclease inhibitor that function in diverse biological processes, including protein post-translational modifications, epithelial-mesenchymal transition, cell migration and redox homeostasis, which have not previously been reported to interact with RASSF2. We independently validated two of these novel interactions, C1QBP and Vimentin and found that the interaction with C1QBP was enhanced by K-Ras whereas, interestingly, the Vimentin interaction was reduced by K-Ras. Additionally, RASSF2/K-Ras regulated the acetylation of Vimentin. Our data thus reveal novel mechanisms by which RASSF2 may exert its functions, several of which may be Ras-regulated.

Proteomic analysis of anatoxin-a acute toxicity in zebrafish reveals gender specific responses and additional mechanisms of cell stress

Anatoxin-a is a potent neurotoxin produced by several genera of cyanobacteria. Deaths of wild and domestic animals due to anatoxin-a exposure have been reported following a toxic response that is driven by the inhibition of the acetylcholine receptors at neuromuscular junctions. The consequent neuron depolarization results in an overstimulation of the muscle cells. In order to unravel further molecular events implicated in the toxicity of anatoxin-a, a proteomic investigation was conducted. Applying two-dimensional gel electrophoresis (2DE) and MALDI-TOF mass spectrometry, we report early proteome changes in brain and muscle of zebrafish (Danio rerio) caused by acute exposure to anatoxin-a. In this regard, the test group of male and female zebrafish received an intraperitoneal (i.p.) injection of an anatoxin-a dose of 0.8µgg(-1) of fish body weight (bw) in phosphate buffered saline solution (PBS), while the control received an i.p. injection of PBS only. Five minutes after i.p. injection, brain and muscle tissues were collected, processed and analyzed with 2DE. Qualitative and quantitative analyzes of protein abundance allowed the detection of differences in the proteome of control and exposed fish groups, and between male and female fish (gender specific responses). The altered proteins play functions in carbohydrate metabolism and energy production, ATP synthesis, cell structure maintenance, cellular transport, protein folding, stress response, detoxification and protease inhibition. These changes provide additional insights relative to the toxicity of anatoxin-a in fish. Taking into account the short time of response considered (5min of response to the toxin), the changes in the proteome observed in this work are more likely to derive from fast occurring reactions in the cells. These could occur by protein activity regulation through degradation (proteolysis) and/or post-translational modifications, than from a differential regulation of gene expression, which may require more time for proteins to be synthesized and to produce changes at the proteomic level.

Joint modeling of cell and nuclear shape variation

Modeling cell shape variation is critical to our understanding of cell biology. Previous work has demonstrated the utility of nonrigid image registration methods for the construction of nonparametric nuclear shape models in which pairwise deformation distances are measured between all shapes and are embedded into a low-dimensional shape space. Using these methods, we explore the relationship between cell shape and nuclear shape. We find that these are frequently dependent on each other and use this as the motivation for the development of combined cell and nuclear shape space models, extending nonparametric cell representations to multiple-component three-dimensional cellular shapes and identifying modes of joint shape variation. We learn a first-order dynamics model to predict cell and nuclear shapes, given shapes at a previous time point. We use this to determine the effects of endogenous protein tags or drugs on the shape dynamics of cell lines and show that tagged C1QBP reduces the correlation between cell and nuclear shape. To reduce the computational cost of learning these models, we demonstrate the ability to reconstruct shape spaces using a fraction of computed pairwise distances. The open-source tools provide a powerful basis for future studies of the molecular basis of cell organization.

Characterization of antiproliferative potential and biological targets of a copper compound containing 4'-phenyl terpyridine

Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4'-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.

Deregulation of the EGFR/PI3K/PTEN/Akt/mTORC1 pathway in breast cancer: possibilities for therapeutic intervention

The EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway plays prominent roles in malignant transformation, prevention of apoptosis, drug resistance and metastasis. The expression of this pathway is frequently altered in breast cancer due to mutations at or aberrant expression of: HER2, ERalpha, BRCA1, BRCA2, EGFR1, PIK3CA, PTEN, TP53, RB as well as other oncogenes and tumor suppressor genes. In some breast cancer cases, mutations at certain components of this pathway (e.g., PIK3CA) are associated with a better prognosis than breast cancers lacking these mutations. The expression of this pathway and upstream HER2 has been associated with breast cancer initiating cells (CICs) and in some cases resistance to treatment. The anti-diabetes drug metformin can suppress the growth of breast CICs and herceptin-resistant HER2+ cells. This review will discuss the importance of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway primarily in breast cancer but will also include relevant examples from other cancer types. The targeting of this pathway will be discussed as well as clinical trials with novel small molecule inhibitors. The targeting of the hormone receptor, HER2 and EGFR1 in breast cancer will be reviewed in association with suppression of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway.