Raf kinase inhibitor protein mediates intestinal epithelial cell apoptosis and promotes IBDs in humans and mice.

OBJECTIVE: Raf kinase inhibitor protein (RKIP) appears to control cancer cell metastasis and its expression in colonic tissue is related to colonic cancer development. We sought to identify the roles of RKIP in maintaining homeostasis of GI tract. DESIGN: The expression of RKIP was determined by immunohistochemistry and western blot analysis. RKIP knockout and wild-type mice were administered dextran sulfate sodium (DSS) or 2,4,6-trinitrobenzenesulfonic acid (TNBS) to induce experimental colitis, and the mice were assessed based on colitis symptoms and biochemical approaches. The mechanism was analysed using immunoprecipitation and pull-down experiments. RESULTS: The RKIP expression is positively correlated with the severity of IBD. RKIP deficiency protects mice from DSS-induced or TNBS-induced colitis and accelerated recovery from colitis. RKIP deficiency inhibits DSS-induced infiltration of acute-phase immune cells and reduces production of proinflammatory cytokines and chemokines in colon. RKIP deficiency inhibits DSS-induced or TNBS-induced colonic epithelial barrier damage and intestinal epithelial cell (IEC) apoptosis. RKIP deficiency also inhibits tumour necrosis factor-alpha-induced IEC apoptosis and colitis. Mechanistically, RKIP enhances the induction of P53-upregulated modulator of apoptosis by interacting with TGF-ß-activated kinase 1 (TAK1) and promoting TAK1-mediated NF-κB activation. This is supported by the observation that TAK1 activation is positively correlated with the expression of RKIP in human clinical samples and the development of IBD. CONCLUSIONS: RKIP contributes to colitis development by promoting inflammation and mediating IEC apoptosis and might represent a therapeutic target of IBD.

Increased Expression of miR-23a Mediates a Loss of Expression in the RAF Kinase Inhibitor Protein RKIP.

RAF kinase inhibitor protein (RKIP) is a seminal regulator of intracellular signaling and exhibits both antimetastatic and antitumorigenic properties. Decreased expression of RKIP has been described in several human malignancies, including acute myelogenous leukemia (AML). As the mechanisms leading to RKIP loss in AML are still unclear, we aimed to analyze the potential involvement of miRNAs within this study. miRNA microarray and qPCR data of more than 400 AML patient specimens revealed correlation between decreased expression of RKIP and increased expression of miR-23a, a member of the miR-23a/27a/24-2 cluster. In functional experiments, overexpression of miR-23a decreased RKIP mRNA and protein expression, whereas miR-23a inhibition caused the opposite effect. By using an RKIP 3'-untranslated region luciferase reporter construct with and without mutation or deletion of the putative miR-23a-binding site, we could show that RKIP modulation by miR-23a is mediated via direct binding to this region. Importantly, miR-23a overexpression induced a significant increase of proliferation in hematopoietic cells. Simultaneous transfection of an RKIP expression construct lacking the miR-23a-binding sites reversed this phenotype, indicating that this effect is truly mediated via downregulation of RKIP. Finally, by analyzing more than 4,300 primary patient specimens via database retrieval from The Cancer Genome Atlas, we could highlight the importance of the miR-23a/RKIP axis in a broad range of human cancer entities. In conclusion, we have identified miR-23a as a negative regulator of RKIP expression in AML and have provided data that suggest the importance of our observation beyond this tumor entity. Cancer Res; 76(12); 3644-54. ©2016 AACR.

Identification, Functional Study, and Promoter Analysis of HbMFT1, a Homolog of MFT from Rubber Tree (Hevea brasiliensis).

A homolog of MOTHER OF FT AND TFL1 (MFT) was isolated from Hevea brasiliensis and its biological function was investigated. Protein multiple sequence alignment and phylogenetic analysis revealed that HbMFT1 conserved critical amino acid residues to distinguish MFT, FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1)-like proteins and showed a closer genetic relationship to the MFT-like group. The accumulation of HbMFT1 was generally detected in various tissues except pericarps, with the highest expression in embryos and relatively higher expression in roots and stems of seedlings, flowering inflorescences, and male and female flowers. HbMFT1 putative promoter analysis showed that tissue-specific, environmental change responsive and hormone-signaling responsive elements were generally present. HbMFT1 was strongly induced under a short-day condition at 28 °C, with the highest expression after the onset of a day. Overexpression of HbMFT1 inhibited seed germination, seedling growth, and flowering in transgenic Arabidopsis. The qRT-PCR further confirmed that APETALA1 (AP1) and FRUITFULL (FUL) were drastically down-regulated in 35S::HbMFT1 plants. A histochemical ß-glucuronidase (GUS) assay showed that HbMFT1::GUS activity was mainly detected in stamens and mature seeds coinciding with its original expression and notably induced in rosette leaves and seedlings of transgenic Arabidopsis by exogenous abscisic acid (ABA) due to the presence of ABA cis-elements in HbMFT1 promoter. These results suggested that HbMFT1 was mainly involved in maintenance of seed maturation and stamen development, but negatively controlled germination, growth and development of seedlings and flowering. In addition, the HbMFT1 promoter can be utilized in controlling transgene expression in stamens and seeds of rubber tree or other plant species.

A five-variable signature predicts radioresistance and prognosis in nasopharyngeal carcinoma patients receiving radical radiotherapy.

Radioresistance poses a major challenge in nasopharyngeal carcinoma (NPC) treatment. Clinical tumor-node-metastasis (TNM) staging has limited accuracy in predicting NPC radioresponse and determining its therapeutic regimens. To construct a risk score model for predicting NPC radioresistance, immunohistochemistry was used to assess the expression of four proteins (14-3-3σ, Maspin, RKIP, and GRP78) in 149 NPC samples with different radiosensitivity. Sequentially, a logistic regression analysis was performed to identify independent predictors of NPC radioresistance and establish a risk score model. As a result, a risk score model, Z = -3.189 - 1.478 (14-3-3σ) - 1.082 (Maspin) - 1.666 (RKIP) + 2.499 (GRP78) + 2.597 (TNM stage), was constructed, and a patient's risk score was estimated by the formula: e (Z)/(e (Z) + 1) × 100, where "e" is the base of natural logarithm. High-risk score was closely associated with NPC radioresistance, and was observed more frequently in the radioresistant patients than that in the radiosensitive patients. The sensitivity, specificity, and accuracy of the risk score model for predicting NPC radioresistance was 88.00, 86.48, and 87.25 %, respectively, which was clearly superior to each individual protein and TNM stage. Furthermore, Kaplan-Meier survival analysis showed that high-risk score correlated with the markedly reduced overall survival (OS) and disease-free survival (DFS) of the patients, and Cox regression analysis showed that the risk score model was an independent predictor for OS and DFS. This study constructs a risk score model for predicting NPC radioresistance and patient survival, and it may serve as a complement to current radioresistance risk stratification approaches.

Expression of hPEBP4 negatively correlates with estrogen and progesterone receptors in endometrial carcinoma.

PURPOSE: To investigate the expression of human phosphatidylethanolamine- binding protein 4 (hPEBP4) in endometrial carcinoma and its relation with progesterone receptor (PR) and estrogen receptor (ER). METHODS: Forty-five samples of endometrioid endometrial carcinoma (EEC), 12 samples of atypical endometrial hyperplasia, and 30 samples of normal endometrium were examined. Samples were studied by immunohistochemistry for PR, ER and hPEBP4 expression. Expressions were statistically quantified and analyzed. RESULTS: Expressions of PR and ER were significantly higher in normal endometrium than in cancer. Expression of hPEBP4 was significantly lower in normal endometrium. The expression of hPEBP4 was significantly higher in advanced-stage endometrial cancer, whilst higher but insignificant trend was noticed in higher grade carcinoma. Statistically insignificant trend of negative ER and PR expression with higher grade or stage was noticed. The expression of hPEBP4 was negatively correlated to ER and PR in EEC. CONCLUSION: The expression pattern of hPEBP4 indicated that hPEBP4 interacted with ER and PR in EEC and could thus become a possible target for the development of novel treatment against this malignancy.

Geographic analysis of RKIP expression and its clinical relevance in colorectal cancer.

BACKGROUND: This study evaluates the geographic expression pattern of Raf-1 Kinase Inhibitor Protein (RKIP) in colorectal cancer (CRC) in correlation with clinicopathological and molecular features, markers of epithelial-mesenchymal transition (EMT) and survival outcome. METHODS: Whole-tissue sections of 220 well-characterised CRCs were immunostained for RKIP. NF-κB and E-Cadherin expression was assessed using a matched multi-punch tissue microarray. Analysis of mismatch repair (MMR) protein expression, B-Raf and KRAS mutations was performed. RKIP expression in normal mucosa, tumour centre, invasion front and tumour buds was each assessed for clinical relevance. RESULTS: RKIP was diffusely expressed in normal mucosa and progressively lost towards tumour centre and front (P<0.0001). Only 0.9% of tumour buds were RKIP-positive. In the tumour centre, RKIP deficiency predicted metastatic disease (P=0.0307), vascular invasion (P=0.0506), tumour budding (P=0.0112) and an invasive border configuration (P=0.0084). Loss of RKIP correlated with NF-κB activation (P=0.0002) and loss of E-Cadherin (P<0.0001). Absence of RKIP was more common in MMR-deficient cancers (P=0.0191), while no impact of KRAS and B-Raf mutation was observed. RKIP in the tumour centre was identified as a strong prognostic indicator (HR (95% CI): 2.13 (1.27-3.56); P=0.0042) independently of TNM classification and therapy (P=0.0474). CONCLUSION: The clinical relevance of RKIP expression as an independent prognostic factor is restricted to the tumour centre. Loss of RKIP predicts features of EMT and correlates with frequent distant metastasis.

Immunocytochemical detection of raf kinase inhibitor protein and human papillomavirus profiling of normal and abnormal cervical ThinPrep samples.

OBJECTIVES: This study investigates the potential value of Raf kinase inhibitor protein (RKIP) as a marker of normal squamous cells in ThinPrep slides. RKIP was evaluated for its ability to distinguish between normal and abnormal cervical samples in the context of human papillomavirus (HPV) infections. STUDY DESIGN: A total of 316 ThinPrep samples were taken from women with normal and abnormal cervices. ThinPrep slides were Papanicolaou stained and reported. Residual samples were used for RKIP immunostaining and HPV PCR-based sequencing. RESULTS: RKIP expression was seen in both nuclei and cytoplasm in 83.7% of samples. RKIP expression was highest (84.6%) in samples with a diagnosis of high-grade squamous intraepithelial lesion (HSIL) or worse; expression was lower in low-grade squamous intraepithelial lesions (73%) and was lowest in samples with normal cytology (p = 0.0023). A total of 74% of HPV-infected ThinPrep samples were immunopositive, and 67% of samples that did not harbor HPV were also immunopositive (p = 0.414). Sensitivity and specificity of RKIP were 84.6 and 34.6%, respectively, for the detection of samples with HSIL or worse. CONCLUSIONS: This study showed that RKIP expression may be of some value as a marker for abnormal cervical cells. Combined RKIP expression and HPV testing could improve the identification of samples with abnormal cytology.

Raf kinase inhibitor protein (RKIP) and phospho-RKIP expression in melanomas.

Melanoma, a cancer notorious for its high potential to metastasize, arises from melanocytes, cells dedicated to melanin production and located in the basal layer of the epidermis. Raf-1 kinase inhibitor protein (RKIP) is an inhibitory molecule that down-regulates the effects of the Ras/Raf/MEK/ERK signaling pathway. The aim of this study was to examine the expression of RKIP and pRKIP in melanomas at different stages. We evaluated the RKIP and pRKIP protein by immunohistochemistry in control skin, pigmented nevi and melanomas, and through Western blotting in human normal melanocytes and in four different melanoma-derived cell lines (WM35, A375, M14, and A2058). Our results demonstrated a correlation between the expression of RKIP and pRKIP, and metastatic ability in melanoma cells. This raises the possibility to analyze both RKIP and pRKIP in all melanomas. Down-regulation of both RKIP and pRKIP expression could represent a useful marker of metastatic melanoma. On the contrary for non-metastatic melanoma, especially in Clark I and II, low RKIP and high pRKIP expression could be indicative. In conclusion, the observed negative correlation of the RKIP and pRKIP expression in metastatic melanomas indicates that expression of these proteins may become a prognostic marker for the progression of human cutaneous melanoma. We propose that the investigation of both RKIP and pRKIP may provide a useful tool indicative for metastatic or non-metastatic melanoma in different Clark's level melanomas. Further studies are required to verify the molecular background of the observed RKIP and pRKIP variations.

Low RKIP expression associates with poor prognosis in bladder cancer patients.

Urothelial bladder cancer (UBC) is a heterogeneous type of disease. It is urgent to screen biomarkers of tumour aggressiveness in order to clarify the clinical behaviour and to personalize therapy in UBC patients. Raf kinase inhibitory protein (RKIP) is a metastasis suppressor, and its downregulation is associated with metastatic events in an increasing number of solid tumours. We evaluated the clinical and prognostic significance of RKIP expression in patients with high risk of progression UBC. Using immunohistochemistry, we determined RKIP expression levels in a series of 81 patients with high-grade pT1/pTis or muscle-invasive UBC. Staining of CD31 and D2-40 was used to assess blood and lymphatic vessels, in order to distinguish between blood and lymphatic vessel invasion (LVI). We found that 90 % of pT1/pTis tumours, 94 % of non-muscle invasive papillary tumours and 76 % of the cases without LVI occurrence expressed RKIP in >10 % of cells. In this group, we observed a subgroup of tumours (42 %) in which the tumour centre was significantly more intensely stained than the invasion front. This heterogeneous pattern was observed in 63 % of the cases with LVI. Low RKIP expression was associated with poorer 5-year disease-free and overall survival rates, and remained as an independent prognostic factor for disease-free survival. Loss of RKIP expression may be an important prognostic factor for patients with high risk of progression bladder cancer.

Molecular markers predict distant metastases after adjuvant chemoradiation for rectal cancer.

PURPOSE: The outcomes of adjuvant chemoradiation for locally advanced rectal cancer are nonuniform among patients with matching prognostic factors. We explored the role of molecular markers for predicting the outcome of adjuvant chemoradiation for rectal cancer patients. METHODS AND MATERIALS: The study included 68 patients with stages II to III rectal adenocarcinoma who were treated with total mesorectal excision and adjuvant chemoradiation. Chemotherapy based on 5-fluorouracil and leucovorin was intravenously administered each month for 6-12 cycles. Radiation therapy consisted of 54 Gy delivered in 30 fractions. Immunostaining of surgical specimens for COX-2, EGFR, VEGF, thymidine synthase (TS), and Raf kinase inhibitor protein (RKIP) was performed. RESULTS: The median follow-up was 65 months. Eight locoregional (11.8%) and 13 distant (19.1%) recurrences occurred. Five-year locoregional failure-free survival (LRFFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) rates for all patients were 83.9%, 78.7%, 66.7%, and 73.8%, respectively. LRFFS was not correlated with TNM stage, surgical margin, or any of the molecular markers. VEGF overexpression was significantly correlated with decreased DMFS (P=.045), while RKIP-positive results were correlated with increased DMFS (P=.025). In multivariate analyses, positive findings for COX-2 (COX-2+) and VEGF (VEGF+) and negative findings for RKIP (RKIP-) were independent prognostic factors for DMFS, DFS, and OS (P=.035, .014, and .007 for DMFS; .021, .010, and <.0001 for DFS; and .004, .012, and .001 for OS). The combination of both COX-2+ and VEGF+ (COX-2+/VEGF+) showed a strong correlation with decreased DFS (P=.007), and the combinations of RKIP+/COX-2- and RKIP+/VEGF- showed strong correlations with improved DFS compared with the rest of the patients (P=.001 and <.0001, respectively). CONCLUSIONS: Molecular markers can be valuable in predicting treatment outcome of adjuvant chemoradiation for rectal cancer patients.

PEBP1 downregulation is associated to poor prognosis in HCC related to hepatitis B infection.

BACKGROUND & AIMS: Phosphatidylethanolamine-binding protein 1 (PEBP1, also RKIP) plays a pivotal role in cancer by regulating multiple cellular signaling processes and suppressing metastasis in animal models. We examined whether PEBP1 expression in hepatocellular carcinoma (HCC) correlated with the risk of recurrence and survival after resection. METHODS: A randomly selected cohort of 240 Chinese HCC patients, predominantly hepatitis B related, formed the basis of the study. PEBP1 expression levels were evaluated by immunohistochemistry and real-time reverse-transcriptase PCR. Survival analysis was performed by univariate and multivariate analyses. The results were further validated in an independent series of 403 patients. The relevance of PEBP1 to phospho-ERK was determined by Western blot analysis on clinical samples and hepatoma cell lines. RESULTS: PEBP1, prevalently down-regulated in HCC, was significantly associated with tumor invasive characteristics (such as vascular invasion, lack of encapsulation, poor differentiation and large size). Both PEBP1 protein and mRNA levels were independent predictors for tumor recurrence (hazard ratio (HR) = 1.877, p=0.001; HR = 2.633, p = 0.001; respectively), and patient survival (HR = 1.796, p = 0.004; HR = 1.730, p = 0.044; respectively). The prognostic value of PEBP1 was then confirmed in the validation cohort. In addition, Western blot suggested that loss of PEBP1 led to hyperactivity of MAPK signaling. CONCLUSIONS: Down-regulation of PEBP1 in HCC indicated aggressive tumor behaviors and predicted a worse clinical outcome, which may be a useful biomarker to identify the patients at high risk of post-operative recurrence.

Immunohistochemical detection of the Raf kinase inhibitor protein in nonneoplastic gastric tissue and gastric cancer tissue.

Expression of the Raf kinase inhibitor protein (RKIP), a metastasis suppressor, is high in normal tissues, low in primary cancers, and lowest or absent in metastatic cancers. Here, we studied the expression of RKIP in nonneoplastic gastric tissue and gastric cancer tissue by immunohistochemistry (IHC) and evaluated its role in the genesis and metastasis of gastric cancer. RKIP immunoreactivity was evaluated in 40 samples of nonneoplastic gastric tissues and 75 samples of gastric cancer tissues. Among the 40 samples of nonneoplastic gastric tissue, 35 (87.5%) were positive for RKIP expression and 5 (12.5%) were negative; in the 75 samples of primary gastric cancer tissue, 39 (52%) were positive for RKIP expression and 36 (48%) were negative. Among 26 samples of metastatic lymph node tissues, 5 (19.2%) were positive for RKIP expression and 21 (80.8%) were negative. RKIP expression level was highest in nonneoplastic gastric tissue, low in primary gastric cancer tissue, and lowest or undetectable in metastatic gastric cancer tissue. Our data suggest that RKIP may play a role in the genesis and metastasis of gastric cancer.

Loss of RKIP expression is associated with poor survival in GISTs.

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal tumours of the digestive tract and are commonly driven by oncogenic mutations in KIT and PDGFRA genes. Tumour size, location, mitotic index and KIT/PDGFRA mutations are the most important prognostic parameters in GISTs. However, additional studies screening for new molecular prognostic markers in GISTs are missing. Raf kinase inhibitor protein (RKIP) has been considered as a suppressor of metastasis and a prognostic marker in several neoplasms. In the present study we aimed to examine whether RKIP expression is associated with GIST clinical-pathological features. Using immunohistochemistry, we determined RKIP expression levels in a well-characterised series of 70 GISTs. We found that RKIP is expressed in the great majority of cases, and absent in approximately 9% of GISTs. Additionally, we found that loss of RKIP expression was not due to the promoter methylation as assessed by methylation-specific PCR. Loss of RKIP expression was associated with poor disease-specific survival and with tumour necrosis in GISTs. Furthermore, a statistical tendency was observed between the positive RKIP expression and absence of metastasis. So far, this is the first study assessing RKIP expression levels in GISTs. We conclude that loss of RKIP expression could have an important role as prognostic marker in GISTs.

Low levels of raf kinase inhibitory protein in growth hormone-secreting pituitary adenomas correlate with poor response to octreotide treatment.

CONTEXT: Excessive GH production by pituitary tumors causes acromegaly. Medical treatment of acromegaly with somatostatin analogs (SMSs), like octreotide, is well established, but the clinical effect is variable. One mechanism for octreotide effect is inhibition of the MAPK signaling pathway after binding to the G protein-coupled somatostatin receptor. Nonphosphorylated Raf kinase inhibitory protein (RKIP) binds to and inhibits Raf1 kinase, and thereby attenuates MAPK signaling, whereas phosphorylated RKIP inhibits G protein receptor internalization and degradation due to inhibition of G protein receptor kinase 2. OBJECTIVE: Our objective was to study RKIP levels in pituitary somatotroph adenomas, and relate them to clinical characteristics and response to octreotide treatment in patients with acromegaly. PATIENTS AND METHODS: RKIP level was analyzed by Western blot of proteins extracted from somatotroph tumors frozen a short time after surgery in 51 patients with active acromegaly. An acute somatostatin test was performed in 46 of the patients, and in 21 the IGF-I level before and 6 months after SMS treatment was available. RESULTS: The adenoma RKIP level correlated significantly to both the acute and the long-term octreotide responses on serum levels of GH and IGF-I, respectively. In multiple regression analyses, the RKIP level was a significant determinant for both the GH reduction in the acute test and the IGF-I reduction after approximately 6 months. CONCLUSION: The RKIP level in somatotroph adenomas seems to be important for the clinical effect of SMS treatment, in which low levels of RKIP correlate to poor clinical response to SMSs.

[Differential analysis of proteomic profiles between cryptorchid and normal mouse testes].

To screen factors related to spermatogonial stem cell (SSC) proliferation, and to investigate the mechanism of infertility caused by cryptorchidism, ten-day-old Kunming (KM) mice were used and experimental cryptorchidism was conducted. On the 35th day after cryptorchid operation, the left testes were fixed in Bouin's fluid and used for histological analysis. The testes of 45-day-old mice were subjected to the same histological analysis, and it was found that they contained germ cells at every stage of development, from SSCs to sperm, indicating that the animals were fully sexually mature at this age. While in experimental cryptorchid mice, the spermatogenesis was arrested at the stage of spermatocytes, and only spermatogonia and primary spermatocytes were present in cryptorchid testes. The proportion of spermatogonia to other types of germ cells was much higher than that in sexually mature mice. On the other hand, the right testes were used for proteomic analysis. The total protein in testes was extracted on the 35th day after cryptorchid operation. The differentially expressed proteins in cryptorchid mice and sexually mature mice were screened and compared by the proteomic techniques. Through the separation of two-dimensional gel electrophoresis (2-DE), 20 differential protein spots were found, and 9 of them were digested and identified by the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrum. In cryptorchid mice, 6 out of 9 proteins were down-regulated, and 3 were up-regulated. Among these proteins, 4 proteins were identified, and they were Stathmin, phosphatidylethanolamine-binding protein1 (PEBP1), HES-related basic helix-loop-helix protein (HERP), and one unnamed protein (we temporarily named it Px). More Stathmin, PEBP1 and Px were expressed in sexually mature mice than in experimental cryptorchid mice. But HERP1 was the other way round. In the present study, we have screened 4 proteins related to cryptorchidism. It is helpful to study the mechanism of SSC proliferation and infertility caused by cryptorchidism.

Identification of novel molecular candidates for acute liver failure in plasma of BALB/c murine model.

In an effort to identify proteins involved in the disease process of acute liver failure (ALF), we investigated changes in the plasma proteome associated with d-galactosamine/lipopolysaccharide (GalN/LPS) treatment of BALB/c mice. The plasma samples from mice with ALF and control were screened for potential differences using two-dimensional electrophoresis followed by liquid chromatography-electrospray ionization-tandem mass spectrometry or matrix associated laser desorption ionization-time-of-flight mass spectrometry. The expression levels of candidate protein named phosphatidylethanolamine binding protein (PEBP) in plasma and liver, brain tissues were confirmed by western blot and RT-PCR analyses. Results were confirmed in plasma samples of human beings. Seven proteins existed in plasma of GalN/LPS-treatment animals only but not in controls. They included PEBP, regucalcin, Cu/Zn superoxide dismutase, glyoxalase 1, malate dehydrogenase, proteasome subunit alpha type 1, and HPMS haptoglobin precursor. Two proteins, proteasome subunit alpha type 5 and apolipoprotein A-I precursor, were up-regulated by GalN/LPS, and one protein, HPMS haptoglobin precursor, was down-regulated by this treatment. Western blot analysis confirmed the results that PEBP protein levels increased significantly in plasma and liver tissues only in ALF mice, but not in surviving mice treated with GalN/LPS. Further analysis revealed that GalN/LPS also induced up-regulation of PEBP mRNA levels in liver tissues. Importantly, plasma obtained from ALF patients, but not from healthy volunteers or from hepatitis patients, also contained detectable levels of PEBP. The present study show that PEBP may be a potential plasma biomarker for ALF diagnosis and participate in the pathphysiological process of ALF.

Loss of raf-1 kinase inhibitor protein expression is associated with tumor progression and metastasis in colorectal cancer.

Raf-1 kinase inhibitor protein (RKIP) is known as a critical down-regulator of the mitogen-activated protein kinase signaling pathway and a potential molecular determinant of malignant metastasis. The aim of this study was to determine the prognostic significance of RKIP expression in colorectal cancer (CRC). Immunohistochemical staining for RKIP was performed on a tissue microarray comprising 1,197 mismatch repair (MMR)-proficient and 141 MMRdeficient CRCs. The association of RKIP with clinicopathologic features was analyzed. Loss of cytoplasmic RKIP was associated with distant metastasis (P = .038), higher N stage (P = .032), vascular invasion (P = .01), and worse survival (P = .001) in the MMR-proficient group. In MMR-deficient CRCs, loss of cytoplasmic RKIP was associated with distant metastasis (P = .043) and independently predicted worse survival (P = .004). Methylation analysis of 28 cases showed that loss of RKIP expression is unlikely to be due to promoter methylation.Loss of RKIP expression is a marker of tumor progression and distant metastasis in MMR-proficient and MMR-deficient CRCs.

Bystander effects are induced by CENU treatment and associated with altered protein secretory activity of treated tumor cells: a relay for chemotherapy?

In a previous study, it was reported that secondary untreated melanoma tumors implanted several weeks after and at distance from primary chloroethylnitrosourea (CENU)-treated tumors underwent differentiation and growth inhibition. To see whether the primary treated tumor released soluble factors that mediated the secondary tumor response, serum transfer experiments were performed in vivo. Administration of serum from CENU-treated tumor-bearing donors arrested tumor proliferation, decreased vessel formation and induced tumor metabolite alterations encompassing glutathione decrease and polyunsaturated fatty acid and phosphoethanolamine increase. These changes mimicked secondary tumor phenotype. To reproduce the model in vitro, cell culture supernatant transfer experiments were performed. CENU-treated cell cultures showed polyploidy and reactive oxygen species (ROS) production. Cell cultures challenged by a conditioned medium of CENU-treated cells underwent growth inhibition, cytoskeleton disorders, cytokinesis retardation, metabolite alterations, glutathione decrease and phosphoethanolamine increase, without ROS elicitation. Proteomics of CENU-treated cell conditioned media revealed altered protein secretion activity by CENU-treated cells. Among de novo secreted proteins, the most expressed were phosphatidylethanolamine-binding protein (PEBP), cardiovascular heat shock protein (cHsp), Rho-associated coiled-coil forming kinase 2 (ROCK) and actin fragments. These proteins testified of cytoskeleton disorders, growth inhibition and metabolite alterations. This article demonstrates the release by CENU-treated tumors of growth inhibitory differentiation-inducing soluble factors. These factors mediate remote bystander effects and attest persistent biological activity of residual tumors after chemotherapy.

A mouse sperm decapacitation factor receptor is phosphatidylethanolamine-binding protein 1.

Capacitation is a pivotal event for mammalian spermatozoa, involving the loss of surface proteins known as decapacitation factors (DF) and consequent acquisition of fertilizing ability. Earlier studies showed that a mouse sperm DF binds to a receptor, DF-R, whose attachment to the sperm plasma membrane appears to involve a glycosylphosphatidylinositol (GPI) anchor. In the present study, purification and subsequent sequencing of DF-R has identified this approximately 23 kDa protein as phosphatidylethanolamine-binding protein 1 (PEBP 1). To obtain functional evidence that supports sequence homology data, purified recombinant PEBP 1 and PEBP 2 were evaluated for biological activity. While PEBP 1 was able to remove DF activity in solution at concentrations above approximately 1 nmol/l, PEBP 2 was ineffective, even at 600 nmol/l; this confirmed that DF-R is PEBP 1. Anti-PEBP 1 antiserum recognized recombinant PEBP 1 and a approximately 23 kDa protein in both mouse and human sperm lysates. Immunolocalization studies revealed that DF-R/PEBP 1 is located on the acrosomal cap, the post-acrosomal region and the flagellum of both mouse and human spermatozoa, with epitope accessibility being capacitation state-dependent and reversible. Treatment of cells with a phospholipase able to cleave GPI anchors essentially abolished immunostaining, thus confirming the extracellular location of DF-R/PEBP 1. We suggest that DF-R/PEBP 1 plays its fundamental role in capacitation by causing alterations in the sperm plasma membrane in both head and flagellum, with functional consequences for membrane-associated proteins. Obtaining more detail about DF <--> DF-R interactions could lead to useful applications in both fertility treatments and new contraceptive approaches.

Proteomic analysis of formalin-fixed prostate cancer tissue.

Proteomic analysis of formalin-fixed paraffin-embedded (FFPE) tissue would enable retrospective biomarker investigations of this vast archive of pathologically characterized clinical samples that exist worldwide. These FFPE tissues are, however, refractory to proteomic investigations utilizing many state of the art methodologies largely due to the high level of covalently cross-linked proteins arising from formalin fixation. A novel tissue microdissection technique has been developed and combined with a method to extract soluble peptides directly from FFPE tissue for mass spectral analysis of prostate cancer (PCa) and benign prostate hyperplasia (BPH). Hundreds of proteins from PCa and BPH tissue were identified, including several known PCa markers such as prostate-specific antigen, prostatic acid phosphatase, and macrophage inhibitory cytokine-1. Quantitative proteomic profiling utilizing stable isotope labeling confirmed similar expression levels of prostate-specific antigen and prostatic acid phosphatase in BPH and PCa cells, whereas the expression of macrophage inhibitory cytokine-1 was found to be greater in PCa as compared with BPH cells.