Significance of hyaluronan binding protein (HABP1/P32/gC1qR) expression in advanced serous ovarian cancer patients

Cytoplasmic Shotgun Proteomic Points to Key Proteins and Pathways in Temozolomide-Resistant Glioblastoma Multiforme

Temozolomide (TMZ) is the first line of chemotherapy to treat primary brain tumors of the type glioblastoma multiforme (GBM). TMZ resistance (TMZR) is one of the main barriers to successful treatment and is a principal factor in relapse, resulting in a poor median survival of 15 months. The present paper focuses on proteomic analyses of cytosolic fractions from TMZ-resistant (TMZR) LN-18 cells. The experimental workflow includes an easy, cost-effective, and reproducible method to isolate subcellular fraction of cytosolic (CYTO) proteins, mitochondria, and plasma membrane proteins for proteomic studies. For this study, enriched cytoplasmic fractions were analyzed in replicates by nanoflow liquid chromatography tandem high-resolution mass spectrometry (nLC-MS/MS), and proteins identified were quantified using a label-free approach (LFQ). Statistical analysis of control (CTRL) and temozolomide-resistant (TMZR) proteomes revealed proteins that appear to be differentially controlled in the cytoplasm. The functions of these proteins are discussed as well as their roles in other cancers and TMZ resistance in GBM. Key proteins are also described through biological processes related to gene ontology (GO), molecular functions, and cellular components. For protein-protein interactions (PPI), network and pathway involvement analyses have been performed, highlighting the roles of key proteins in the TMZ resistance phenotypes. This study provides a detailed insight into methods of subcellular fractionation for proteomic analysis of TMZ-resistant GBM cells and the potential to apply this approach to future large-scale studies. Several key proteins, protein-protein interactions (PPI), and pathways have been identified, underlying the TMZ resistance phenotype and highlighting the proteins' biological functions.

Scientific and clinical relevance of non-cellular tumor microenvironment components in ovarian cancer chemotherapy resistance

The tumor microenvironment (TME) components play a crucial role in cancer cells' resistance to chemotherapeutic agents. This phenomenon is exceptionally fundamental in patients with ovarian cancer (OvCa), whose outcome depends mainly on their response to chemotherapy. Until now, most reports have focused on the role of cellular components of the TME, while less attention has been paid to the stroma and other non-cellular elements of the TME, which may play an essential role in the therapy resistance. Inhibiting these components could help define new therapeutic targets and potentially restore chemosensitivity. The aim of the present article is both to summarize the knowledge about non-cellular components of the TME in the development of OvCa chemoresistance and to suggest targeting of non-cellular elements of the TME as a valuable strategy to overcome chemoresistance and to develop new therapeutic strategies in OvCA patients.

gC1qR: A New Target for Cancer Immunotherapy

Although breakthroughs in cancer treatment have been achieved, immunotherapy yields only modest benefits in most patients. There is still a gap in clarifying the immune evasiveness and immune-resistance mechanisms. Identifying other candidate targets for cancer immunotherapy is therefore a clear unmet clinical need. The complement system, a pillar of innate immunity, has recently entered the limelight due to its immunoregulatory functions in the tumor microenvironment (TME). In particular, gC1qR, a receptor for globular heads of C1q, serves as a promising new target and has attracted more attention. gC1qR, also named P32/C1qBP/HABP1, is a multifunctional protein that is overexpressed in various cancers and holds prognostic value. It regulates the tumorigenic, progression and metastatic properties of tumor cells through several downstream signaling pathways, including the Wnt/β-catenin, PKC-NF-κB and Akt/PKB pathways. A few preclinical experiments conducted through gC1qR interventions, such as monoclonal antibody, chimeric antigen receptor T-cell (CAR-T) therapy, and tumor vaccination, have shown encouraging results in anticancer activity. The efficacy may rely on the regulatory role on the TME, induction of tumor cells apoptosis and antiangiogenic activity. Nevertheless, the current understanding of the relationship between cancer immunotherapy and gC1qR remains elusive and often contradictory, posing both opportunities and challenges for therapeutic translation in the clinic. In this review, we focus on the current understanding of gC1qR function in cancer immunology and highlight the vital roles in regulating the TME. We also examines the rationale behind targeting gC1qR and discusses the potential for translating into clinical practice.

A Platform of Patient-Derived Microtumors Identifies Individual Treatment Responses and Therapeutic Vulnerabilities in Ovarian Cancer

In light of the frequent development of therapeutic resistance in cancer treatment, there is a strong need for personalized model systems representing patient tumor heterogeneity, while enabling parallel drug testing and identification of appropriate treatment responses in individual patients. Using ovarian cancer as a prime example of a heterogeneous tumor disease, we developed a 3D preclinical tumor model comprised of patient-derived microtumors (PDM) and autologous tumor-infiltrating lymphocytes (TILs) to identify individual treatment vulnerabilities and validate chemo-, immuno- and targeted therapy efficacies. Enzymatic digestion of primary ovarian cancer tissue and cultivation in defined serum-free media allowed rapid and efficient recovery of PDM, while preserving histopathological features of corresponding patient tumor tissue. Reverse-phase protein array (RPPA)-analyses of >110 total and phospho-proteins enabled the identification of patient-specific sensitivities to standard, platinum-based therapy and thereby the prediction of potential treatment-responders. Co-cultures of PDM and autologous TILs for individual efficacy testing of immune checkpoint inhibitor treatment demonstrated patient-specific enhancement of cytotoxic TIL activity by this therapeutic approach. Combining protein pathway analysis and drug efficacy testing of PDM enables drug mode-of-action analyses and therapeutic sensitivity prediction within a clinically relevant time frame after surgery. Follow-up studies in larger cohorts are currently under way to further evaluate the applicability of this platform to support clinical decision making.

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.

Noninvasive evaluation of HABP1 expression with 99mTc-labeled small-interference RNA in ovarian cancer

PURPOSE

Ovarian cancer is one of the most common gynecological cancers in women with a low 5-year survival rate. Evaluation of hyaluronic acid-binding protein 1 (HABP1) level can provide important information for the diagnosis and treatment of ovarian cancer. In this study, we designed a novel HABP1 probe based on ^99mTc-radiolabeled small-interference RNA (siRNA) for detecting HABP1 expression noninvasively in vivo, thereby providing a new method for its diagnosis and treatment.

METHODS

A specific siHABP1 was selected because of its targetability and silencing effect. A negative control siRNA (NCsiRNA) with no homology with the human genome was used. SiHABP1 and NCsiRNA were radiolabeled with ^99mTc using the bifunctional chelating agent hydrazinonicotinamide (HYNIC). The radiochemical purity and in vitro stability of the probe were determined by HPLC. The binding activity was measured by western blotting (WB) and RT-PCR. The HABP1-overexpressing human ovarian cancer cell line HO-8910 was used for cell uptake experiments, which were performed with or without transfection and measured with a gamma counter. HO8910-bearing mice were imaged at 1, 4, and 10 h, and biodistribution analysis was performed at 1, 4, 6, and 10 h after injection of ^99mTc-HYNIC-siRNA.

RESULTS

^99mTc-HYNIC-siHABP1 had high radiochemical purity and good in vitro stability, and showed the same binding capacity and silencing effect as siHABP1. SPECT imaging showed that tumors were clearly visualized at 10 h after injection of ^99mTc-HYNIC-siHABP1 but not after ^99mTc-HYNIC-NCsiRNA, implying specific binding. The biodistribution results were consistent with those of SPECT imaging.

CONCLUSIONS

We showed that ^99mTc-HYNIC-siHABP1 is a feasible probe for the noninvasive visualization of HABP1 expression in ovarian cancer.

The Complement System in Ovarian Cancer: An Underexplored Old Path

Ovarian cancer is one of the most lethal gynecological cancers. Current therapeutic strategies allow temporary control of the disease, but most patients develop resistance to treatment. Moreover, although successful in a range of solid tumors, immunotherapy has yielded only modest results in ovarian cancer. Emerging evidence underscores the relevance of the components of innate and adaptive immunity in ovarian cancer progression and response to treatment. Particularly, over the last decade, the complement system, a pillar of innate immunity, has emerged as a major regulator of the tumor microenvironment in cancer immunity. Tumor-associated complement activation may support chronic inflammation, promote an immunosuppressive microenvironment, induce angiogenesis, and activate cancer-related signaling pathways. Recent insights suggest an important role of complement effectors, such as C1q or anaphylatoxins C3a and C5a, and their receptors C3aR and C5aR1 in ovarian cancer progression. Nevertheless, the implication of these factors in different clinical contexts is still poorly understood. Detailed knowledge of the interplay between ovarian cancer cells and complement is required to develop new immunotherapy combinations and biomarkers. In this context, we discuss the possibility of targeting complement to overcome some of the hurdles encountered in the treatment of ovarian cancer.

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.

gC1qR/HABP1/p32 Is a Potential New Therapeutic Target Against Mesothelioma

Mesothelioma is an aggressive cancer of the serous membranes with poor prognosis despite combination therapy consisting of surgery, radiotherapy, and platinum-based chemotherapy. Targeted therapies, including immunotherapies, have reported limited success, suggesting the need for additional therapeutic targets. This study investigates a potential new therapeutic target, gC1qR/HABP1/p32 (gC1qR), which is overexpressed in all morphologic subtypes of mesothelioma. gC1qR is a complement receptor that is associated with several cellular functions, including cell proliferation and angiogenesis. In vitro and in vivo experiments were conducted to test the hypothesis that targeting gC1qR with a specific gC1qR monoclonal antibody 60.11 reduces mesothelioma tumor growth, using the biphasic mesothelioma cell line MSTO-211H (MSTO). In vitro studies demonstrate cell surface and extracellular gC1qR expression by MSTO cells, and a modest 25.3 ± 1.8% (n = 4) reduction in cell proliferation by the gC1qR blocking 60.11 antibody. This inhibition was specific for targeting the C1q binding domain of gC1qR at aa 76–93, as a separate monoclonal antibody 74.5.2, directed against amino acids 204–218, had no discernable effect. In vivo studies, using a murine orthotopic xenotransplant model, demonstrated an even greater reduction in MSTO tumor growth (50% inhibition) in mice treated with the 60.11 antibody compared to controls. Immunohistochemical studies of resected tumors revealed increased cellular apoptosis by caspase 3 and TUNEL staining, in 60.11 treated tumors compared to controls, as well as impaired angiogenesis by decreased CD31 staining. Taken together, these data identify gC1qR as a potential new therapeutic target against mesothelioma with both antiproliferative and antiangiogenic properties.

Globular C1q Receptor (gC1qR/p32/HABP1) Suppresses the Tumor-Inhibiting Role of C1q and Promotes Tumor Proliferation in 1q21-Amplified Multiple Myeloma

Immunodeficiencies are widely becoming known as important features of multiple myeloma (MM) and may promote the proliferation of malignant cells as well as confer resistance to therapy. Few studies focus on the immunomodulatory effects of the complement system on MM. This study aims to explore the role of C1q in MM patients. Plasma C1q was found to be significantly reduced in MM patients, and the amount of C1q deposited around the CD138⁺ cells in bone marrow (BM) biopsy sections was observed to be much higher, especially in the subgroup with 1q21 amplification (Amp1q21). CD138⁺ cells expressed higher levels of C1q receptors (C1qRs) than CD138⁻ cells. Patients with Amp1q21 expressed higher levels of globular C1qR (gC1qR), whereas patients without Amp21 expressed higher levels of collagen tail C1qR (cC1qR). Additionally, gC1qR was noted to suppress the MM-inhibiting role of C1q in H929, U266, and MM1S. gC1qR interacts with insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which also suppressed the function of C1q and regulated CDC28 protein kinase regulatory subunit 1B (CKS1B) mRNA. In summary, gC1qR suppressed the MM-inhibiting role of C1q and regulated CKS1B mRNA in promoting tumor proliferation via IGF2BP3 in 1q21-amplified MM. Our findings provide novel evidence on how MM cells evade the immune system and promote survival as well as suggest possible novel targets for future therapies of MM.

p32/C1QBP regulates OMA1-dependent proteolytic processing of OPA1 to maintain mitochondrial connectivity related to mitochondrial dysfunction and apoptosis

Mitochondria are dynamic organelles that undergo fusion and fission in response to various physiological and stress stimuli, which play key roles in diverse mitochondrial functions such as energy metabolism, intracellular signaling, and apoptosis. OPA1, a mitochondrial dynamin-like GTPase, is responsible for the inner membrane fusion of mitochondria, and the function of OPA1 is regulated by proteolytic cleavage in response to various metabolic stresses. Growing evidences highlighted the importance of mitochondrial adaptation in response to metabolic stimuli. Here, we demonstrated the role of p32/C1QBP in mitochondrial morphology by regulating OMA1-dependent proteolytic processing of OPA1. Genetic ablation of p32/C1QBP activates OMA1, cleaves OPA1, and leads mitochondrial fragmentation and swelling. The loss of p32/C1QBP decreased mitochondrial respiration and lipid utilization, sensitized cells to mitochondrial stress, and triggered a metabolic shift from oxidative phosphorylation to glycolysis, which were correlated with apoptosis in cancer cells and the inhibition of 3D-spheroid formation. These results suggest a unique regulation of cell physiology by mitochondria and provide a basis for a new therapeutic strategy for cancer.

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.

Tumor-Targeting, MicroRNA-Silencing Porous Silicon Nanoparticles for Ovarian Cancer Therapy

Silencing of aberrantly expressed microRNAs (miRNAs or miRs) has emerged as one of the strategies for molecular targeted cancer therapeutics. In particular, miR-21 is an oncogenic miRNA overexpressed in many tumors, including ovarian cancer. To achieve efficient administration of anti-miR therapeutics, delivery systems are needed that can ensure local accumulation in the tumor environment, low systemic toxicity, and reduced adverse side effects. In order to develop an improved anti-miR therapeutic agent for the treatment of ovarian cancer, a nanoformulation is engineered that leverages biodegradable porous silicon nanoparticles (pSiNPs) encapsulating an anti-miR-21 locked nucleic acid payload and displaying a tumor-homing peptide for targeted distribution. Targeting efficacy, miR-21 silencing, and anticancer activity are optimized in vitro on a panel of ovarian cancer cell lines, and a formulation of anti-miR-21 in a pSiNP displaying the targeting peptide CGKRK is identified for in vivo evaluation. When this nanoparticulate agent is delivered to mice bearing tumor xenografts, a substantial inhibition of tumor growth is achieved through silencing of miR-21. This study presents the first successful application of tumor-targeted anti-miR porous silicon nanoparticles for the treatment of ovarian cancer in a mouse xenograft model.

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.

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.

Antibody neutralization of cell-surface gC1qR/HABP1/SF2-p32 prevents lamellipodia formation and tumorigenesis

We previously demonstrated that cell-surface gC1qR is a key regulator of lamellipodia formation and cancer metastasis. Here, we screened a monoclonal mouse antibody against gC1qR to prevent cell migration by neutralizing cell-surface gC1qR. The anti-gC1qR antibody prevented growth factor-stimulated lamellipodia formation, cell migration and focal adhesion kinase activation by inactivating receptor tyrosine kinases (RTKs) in various cancer cells such as A549, MDA-MB-231, MCF7 and HeLa cells. The antibody neutralization of cell-surface gC1qR also inhibited angiogenesis because the anti-gC1qR antibody prevented growth factor-stimulated RTK activation, lamellipodia formation, cell migration and tube formation in HUVEC. In addition, we found that A549 tumorigenesis was reduced in a xenograft mouse model by following the administration of the anti-gC1qR antibody. With these data, we can conclude that the antibody neutralization of cell-surface gC1qR could be a good therapeutic strategy for cancer treatment.

The role of the globular heads of the C1q receptor in paclitaxel-induced human ovarian cancer cells apoptosis by a mitochondria-dependent pathway

As a mitochondrial membrane protein, globular C1q receptor (gC1qR) can mediate a variety of biological responses. Our study aims to investigate the role of gC1qR in paclitaxel-induced apoptosis of human ovarian cancer cells and to elucidate its potential molecular mechanism. The level of gC1qR was examined using real-time PCR and western blot analyses. Human ovarian cancer cells viability, migration, and proliferation were detected using the water-soluble tetrazolium salt (WST-1) assay, the transwell assay, and H-thymidine incorporation into DNA (H-TdR) assay, respectively. Apoptosis in cells was assessed using flow cytometric analysis. The intracellular reactive oxygen species was estimated by the fluorescence of H2DCFDA and the mitochondrial membrane potential was tested using a JC-1 probe. The expression of the gC1qR gene decreased significantly in human ovarian cancer tissues relative to the surrounding non-neoplastic ovarian tissues. Cells treated with paclitaxel showed increased gC1qR gene expression, cell apoptosis, and mitochondria dysfunction, and the effects on these cells could be abrogated by the addition of gC1qR small-interfering RNA or α-lipoic acid that was used to protect the mitochondria function. In summary, these data support a mechanism that gC1qR-induced mitochondria dysfunction was involved in the paclitaxel-mediated apoptosis of ovarian cancer cells.

Multi-functional, multicompartmental hyaluronan-binding protein 1 (HABP1/p32/gC1qR): implication in cancer progression and metastasis

Cancer is a complex, multi-factorial, multi-stage disease and a global threat to human health. Early detection of nature and stage of cancer is highly crucial for disease management. Recent studies have proved beyond any doubt about the involvement of the ubiquitous, myriad ligand binding, multi-functional human protein, hyaluronan-binding protein 1 (HABP1), which is identical to the splicing factor associated protein (p32) and the receptor of the globular head of the complement component (gC1qR) in tumorigenesis and cancer metastasis. Simultaneously three laboratories have discovered and named this protein separately as mentioned. Subsequently, different scientists have worked on the distinct functions in cellular processes ranging from immunological response, splicing mechanism, sperm-oocyte interactions, cell cycle regulation to cancer and have concentrated in their respective area of interest, referring it as either p32 or gC1qR or HABP1. HABP1 overexpression has been reported in almost all the tissue-specific forms of cancer and correlated with stage and poor prognosis in patients. In order to tackle this deadly disease and for therapeutic intervention, it is imperative to focus on all the regulatory aspects of this protein. Hence, this work is an attempt to combine an assortment of information on this protein to have an overview, which suggests its use as a diagnostic marker for cancer. The knowledge might assist in the designing of drugs for therapeutic intervention of HABP1/p32/gC1qR regulated specific ligand mediated pathways in cancer.

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.

Increased breast cancer risk with HABP1/p32/gC1qR genetic polymorphism rs2285747 and its upregulation in northern Chinese women

Object

Hyaluronic acid binding protein 1 (HABP1/p32/gC1qR) is overexpressed in breast cancer. However, it is unknown whether HABP1 gene polymorphisms affect breast cancer risk. This study aims to evaluate the potential association of single nucleotide polymorphisms (SNPs) of HABP1 with breast cancer in northern Chinese women.

Results

The minor allele of rs2285747 was strongly associated with breast cancer with OR of 1.553 (95% CI = 1.251–1.927). SNP rs2285747 was also associated with high HABP1 protein expression under the co-dominant and dominant model (p = 0.005, p = 0.019, respectively). For rs2472614, the patients with CG and GG were more likely to have HER2 negative tumors compared to CC (p = 0.015). For rs3786054, the patients with AG and GG were more likely to have HER2 and P53 negative breast cancer compared to AA (p = 0.024, p = 0.064, receptively).

Materials and Methods

Seven SNPs were analyzed in 505 breast cancer patients and 505 controls using SNaPshot method. The associations between SNPs and breast cancer were examined by logistic regression. The associations of SNPs with HABP1 protein expression and disease characteristics were examined by chi-square test.

Conclusions

SNP rs2285747 of HABP1 increased breast cancer risk and elevated its protein expression in northern Chinese women.

Hyaluronic acid binding protein 1 overexpression is an indicator for disease-free survival in cervical cancer

BACKGOUND

Hyaluronic acid binding protein 1 (HABP1) is reported to overexpress in various cancer tissues and may therefore contribute to oncogenesis. However, the status of HABP1 expression in cervical cancer (CC) remains unknown. The aim of this study was to investigate the role of HABP1 and its relationship with clinical characteristics in patients with CC.

METHODS

Immunohistochemistry was used to explore the expression of HABP1 in 30 cervical intra-epithelial neoplasia (CIN) and 118 CC specimens compared to 10 normal cervical specimens.

RESULTS

HABP1 expression was found to be positively higher in CC than in CIN2/3 cases (P = 0.020). Moreover, clinicopathological analysis showed that HABP1 overexpression was associated with advanced FIGO stage (P = 0.001), poor histologic grade (P = 0.013), large tumor size (P = 0.025), LVSI (P = 0.024), deep stromal infiltration (P = 0.001), and lymph node metastasis (P = 0.023). Multivariate analysis suggested that HABP1 overexpression was an independent factor for disease-free survival (DFS) (hazard ratio 3.082; 95% confidence interval 1.372-7.501; P = 0.007).

CONCLUSIONS

The present data provide evidence that HABP1 overexpression predicts CC with high-risk factors and may therefore serve as a new molecular marker for the prediction of DFS in these patients.

Elevated HABP1 protein expression correlates with progression and poor survival in patients with gastric cancer

BACKGROUND

Hyaluronic acid-binding protein 1 (HABP1/gC1qR/p32) has been recently implicated in oncogenesis and cancer progression in various malignancies; however, its clinical role in gastric cancer (GC) is still unclear.

PATIENTS AND METHODS

First, HABP1 expression was determined by Western blot analysis and immunohistochemistry. Then, we evaluated the expression of HABP1 and its clinical significance in tumor tissues from 181 patients with GC.

RESULTS

Expression of HABP1 protein in GC tissues was noticeably higher than that in adjacent nonneoplastic tissues (P=0.018). Increased HABP1 expression was significantly associated with tumor, node, and metastasis (TNM) stage (P=0.006), depth of invasion (P=0.001), lymph node metastasis (P=0.001), liver metastasis (P=0.024), and peritoneum metastasis (P=0.009). Patients with high expression of HABP1 had poor overall survival rate (P<0.001). In addition, histologic grade (P=0.017), TNM stage (P<0.001), Borrmann grouping (P<0.001), depth of invasion (P<0.001), lymph node metastasis (P<0.001), liver metastasis (P=0.010), and tumor size (P<0.001) were independent prognostic factors for overall survival. Multivariate Cox regression analysis revealed that HABP1 (P=0.004), histologic grade (P=0.047), TNM stage (P<0.001), Borrmann grouping (P<0.001), and liver metastasis (P=0.038) were independent factors for overall survival in patients with GC.

CONCLUSION

These findings demonstrated that HABP1 was an indicator for GC progression and poor survival, which highlighted its potential role as a therapeutic target for GCs.

Soluble gC1qR in Blood and Body Fluids: Examination in a Pancreatic Cancer Patient Cohort

BACKGROUND

gC1qR is a multifunctional cellular protein that has been linked to inflammation and cancer. gC1qR is highly upregulated in adenocarcinomas as compared to normal tissue counterparts, and soluble gC1qR (sgC1qR) has been detected in vitro in the pericellular milieu of proliferating malignant cells.

AIM

The present study explored the tissue expression of gC1qR in pancreatic cancer by immunohistochemistry, and the presence of sgC1qR in vivo, by examining blood and malignant effusions from patients with metastatic pancreatic adenocarcinoma.

METHODS

Tissue expression of gC1qR by pancreatic adenocarcinoma was visualized by immunohistochemistry. SgC1qR was quantified in serum from healthy volunteers (n=20) and pancreatic cancer patients (n=34), as well as in malignant pleural (n=23) and peritoneal effusions (n=27), using a newly developed, sensitive immunocapture sandwich ELISA.

RESULTS

Overexpression of gC1qR was confirmed in pancreatic adenocarcinoma compared to nonmalignant pancreatic tissue. Moreover, increased serum levels of sgC1qR (0.29 ± 0.22 ng/ml) were noted in patients with metastatic pancreatic cancer compared to healthy controls (0.15 ± 0.10 ng/ml) (mean ± S.D.) (p=0.035). In 11 of 16 patients for whom sequential samples were available, serum sgC1qR levels rose with disease progression, and paralleled changes in tumor biomarkers, CEA and CA19.9. In addition to blood, sgC1qR was detected in malignant pleural (0.55 ± 0.47 ng/ml) and peritoneal effusions (0.57 ± 0.38 ng/ml).

CONCLUSION

This study provides the first evidence for the presence of sgC1qR in vivo. The ability to detect sgC1qR in blood and body fluids will enable further studies to elucidate its pathophysiology in malignancy.

Complement component 1, q subcomponent binding protein is a marker for proliferation in breast cancer

Complement component 1, q subcomponent binding protein (C1QBP), is a multi-compartmental protein with higher mRNA expression reported in breast cancer tissues. This study evaluated the association between immunohistochemical expression of the C1QBP protein in breast cancer tissue microarrays (TMAs) and clinicopathological parameters, in particular tumor size. In addition, an in vitro study was conducted to substantiate the breast cancer TMA findings. Breast cancer TMAs were constructed from pathological specimens of patients diagnosed with invasive ductal carcinoma. C1QBP protein and proliferating cell nuclear antigen (PCNA) immunohistochemical analyses were subsequently performed in the TMAs. C1QBP immunostaining was detected in 131 out of 132 samples examined. The C1QBP protein was predominantly localized in the cytoplasm of the breast cancer cells. Univariate analysis revealed that a higher C1QBP protein expression was significantly associated with older patients (P = 0.001) and increased tumor size (P = 0.002). Multivariate analysis showed that C1QBP is an independent predictor of tumor size in progesterone-positive tumors. Furthermore, C1QBP was also significantly correlated with expression of PCNA, a known marker of proliferation. Inhibition of C1QBP expression was performed by transfecting C1QBP siRNA into T47D breast cancer cells, a progesterone receptor-positive breast cancer cell line. C1QBP gene expression was analyzed by real-time RT-PCR, and protein expression by Western blot. Cell proliferation assays were also performed by commercially available assays. Down-regulation of C1QBP expression significantly decreased cell proliferation and growth in T47D cells. Taken together, our findings suggest that the C1QBP protein could be a potential proliferative marker in breast cancer.

Overexpression of HABP1 correlated with clinicopathological characteristics and unfavorable prognosis in endometrial cancer

Hyaluronic acid binding protein 1 (HABP1/gC1qR/p32), a ubiquitous multifunctional protein belonging to the hyaladherin family, has been implicated in the tumorigenesis, progression, invasion, and metastasis of several malignant tumors. However, the role of HABP1 in endometrial cancer has not yet been studied. This study aimed to detect the expression of HABP1 in endometrial cancer and explore its role in the clinicopathological features and prognosis of endometrial cancer. We analyzed HABP1 expression by immunohistochemistry in 188 endometrial cancer specimens, 43 benign endometrial lesion specimens, and 41 normal endometrium specimens and assessed using Western blot analysis. Statistical analysis showed that HABP1 was overexpressed in endometrial cancer and benign endometrial lesion compared with normal endometrium (P < 0.001 and P = 0.012, respectively). In addition, HABP1 expression was significantly higher in endometrial cancer than in benign endometrial lesion (P < 0.001). High HABP1 expression was significantly associated with advanced International Federation of Gynecology and Obstetrics stage (P = 0.019), higher histologic grade (P < 0.001), deep myometrial invasion (P = 0.013), lymphovascular space invasion (P = 0.010), lymph node metastasis (P = 0.015), and recurrence (P = 0.009). Patients with high HABP1 expression had a poorer overall survival (OS) and disease-free survival (DFS) than patients with low HABP1 expression (P = 0.015 and P = 0.012, respectively). Multivariate Cox regression analysis showed that the HABP1 expression status was an independent prognostic factor of OS and DFS (P = 0.025 and P = 0.022, respectively) in patients with endometrial cancer. Our results indicated that overexpression of HABP1 may serve as a new biomarker to predict the progression and prognosis of endometrial cancer.

Elevated expression of hyaluronic acid binding protein 1 (HABP1)/P32/C1QBP is a novel indicator for lymph node and peritoneal metastasis of epithelial ovarian cancer patients

The present study aims to clarify whether hyaluronan binding protein 1 (HABP1/p32/C1QBP) is an indicator of peritoneal and lymph node metastasis in epithelial ovarian cancer (EOC), which to the authors' knowledge is not previously reported by others. Western blot analysis demonstrated that HABP1 was highly overexpressed in most metastatic lesions. Of 89 patients whose primary tumors showed high HABP1 expression on immunohistochemical staining, 85 (95.5%) presented peritoneal metastases and 43 (48.3%) had lymph node metastases. Univariate and multivariate logistic regression analyses revealed that HABP1 overexpression correlated with peritoneal dissemination and lymph node metastasis in EOC. The specificity and positive predictive value of HABP1 staining were shown to be better for peritoneal metastasis, while the negative and sensitivity predictive value of HABP1 staining were better for lymph node metastasis. The odds ratio of high versus low staining for peritoneal spread was 9.236 (95% confidence interval (CI), 2.705, 19.316), and that for lymph node metastasis was 8.614 (95% CI, 2.507, 21.039). Furthermore, HABP1 protein may potentially be used alone or in combination with other markers as a predictive marker of EOC patients with lymph node metastasis and/or peritoneal dissemination.