NHERF1/EBP50 is a new marker in colorectal cancer

EBP50 regulates senescence and focal adhesion in endometrial carcinoma

Ezrin-radixin-moesin (ERM)-binding phosphoprotein 50 (EBP50) is a multifunctional scaffold protein that is highly expressed in polarized epithelial cells. Here, we focused on the functional roles of EBP50 in endometrial carcinoma (Em Ca). We analyzed immunohistochemical sections from 121 Em Ca and 30 normal samples. We also characterized EBP50 overexpression or knockout (KO) Em Ca cell lines. High levels of membranous (Me) EBP50 expression were observed in endometrial tissues from normal menstrual cycles, in contrast to the transient upregulation of cytoplasmic (Cyt) EBP50 in tissues in the proliferative phase; this was probably in response to estrogenic effects. There was a significant stepwise reduction of Me-EBP50 expression from grade (G) 1 to G3 Em Cas, which was consistent with the loss of glandular structures. Conversely, Cyt-EBP50 levels increased with in the higher tumor grades. Low Me-EBP50 expression was significantly associated with tumor lymphovascular invasion and short overall survival. Whereas EBP50 KO led to senescence and reduced proliferation and motility, overexpression elicited the opposite phenotypes. Moreover, the number of focal adhesions (FAs), which mediate cell migration, was significantly increased in EBP50 overexpressing cells but decreased in the KO cells. In conclusion, Me- and/or Cyt-EBP50 expression contributes to acceleration of cell motility through enhancement of FA formation, and inhibits senescence to promote cytokinesis. Together, these effects contribute to Em Ca aggressiveness.

Exploring novel protein-based biomarkers for advancing breast cancer diagnosis: A review

This review provides a contemporary examination of the evolving landscape of breast cancer (BC) diagnosis, focusing on the pivotal role of novel protein-based biomarkers. The overview begins by elucidating the multifaceted nature of BC, exploring its prevalence, subtypes, and clinical complexities. A critical emphasis is placed on the transformative impact of proteomics, dissecting the proteome to unravel the molecular intricacies of BC. Navigating through various sources of samples crucial for biomarker investigations, the review underscores the significance of robust sample processing methods and their validation in ensuring reliable outcomes. The central theme of the review revolves around the identification and evaluation of novel protein-based biomarkers. Cutting-edge discoveries are summarised, shedding light on emerging biomarkers poised for clinical application. Nevertheless, the review candidly addresses the challenges inherent in biomarker discovery, including issues of standardisation, reproducibility, and the complex heterogeneity of BC. The future direction section envisions innovative strategies and technologies to overcome existing challenges. In conclusion, the review summarises the current state of BC biomarker research, offering insights into the intricacies of proteomic investigations. As precision medicine gains momentum, the integration of novel protein-based biomarkers emerges as a promising avenue for enhancing the accuracy and efficacy of BC diagnosis. This review serves as a compass for researchers and clinicians navigating the evolving landscape of BC biomarker discovery, guiding them toward transformative advancements in diagnostic precision and personalised patient care.

CRD-BP as a Tumor Marker of Colorectal Cancer

The National Cancer Center published a comparative report on cancer data between China and the United States in the Chinese Medical Journal, which shows that colorectal cancer (CRC) ranks second in China and fourth in the United States. It is worth noting that since 2000, the case fatality rate of CRC in China has skyrocketed, while the United States has gradually declined. Finding tumor markers with high sensitivity and specificity is our primary goal to reduce the case fatality rate of CRC. Studies have shown that CRD-BP (Insulin-like growth factor 2 mRNA-binding protein 1) can affect a variety of signaling pathways, such as Wnt.nuclear factor KB (NF-κB), and Hedgehog, and has good biological effects as a therapeutic target for CRC. CRD-BP is expected to become a tumor marker with high sensitivity and specificity of CRC. This paper reviews the research on CRD-BP as a tumor marker of CRC.

EBP50 Depletion and Nuclear β-Catenin Accumulation Engender Aggressive Behavior of Colorectal Carcinoma through Induction of Tumor Budding

Ezin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a scaffold protein that interacts with several partner molecules including β-catenin. Here, we examined the crosstalk between EBP50 and nuclear catenin during colorectal carcinoma (CRC) progression. In clinical samples, there were no correlations between the subcellular location of EBP50 and any clinicopathological factors. However, EBP50 expression was significantly lower specifically in the outer areas of tumor lesions, in regions where tumor budding (BD) was observed. Low EBP50 expression was also significantly associated with several unfavorable prognostic factors, suggesting that EBP50 depletion rather than its overexpression or subcellular distribution plays an important role in CRC progression. In CRC cell lines, knockout of EBP50 induced epithelial-mesenchymal transition (EMT)-like features, decreased proliferation, accelerated migration capability, and stabilized nuclear β-catenin due to disruption of the interaction between EBP50 and β-catenin at the plasma membrane. In addition, Slug expression was significantly higher in outer lesions, particularly in BD areas, and was positively correlated with nuclear β-catenin status, consistent with β-catenin-driven transactivation of the Slug promoter. Together, our data suggest that EBP50 depletion releases β-catenin from the plasma membrane in outer tumor lesions, allowing β-catenin to accumulate and translocate to the nucleus, where it transactivates the Slug gene to promote EMT. This in turn triggers tumor budding and contributes to the progression of CRC to a more aggressive phase.

Interaction between membranous EBP50 and myosin 9 as a favorable prognostic factor in ovarian clear cell carcinoma

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a scaffold protein that is required for epithelial polarity. Knockout (KO) of membranous EBP50 (Me-EBP50) in ovarian clear cell carcinoma (OCCC) cells induced an epithelial-mesenchymal transition (EMT)-like phenotype, along with decreased proliferation, accelerated migration capability, and induction of cancer stem cell (CSC)-like properties. Shotgun proteomics analysis of proteins that co-immunoprecipitated with EBP50 revealed that Me-EBP50 strongly interacts with myosin 9 (MYH9). Specific inhibition of MYH9 with blebbistatin phenocopied Me-EBP50 KO, and blebbistatin treatment potentiated the effects of Me-EBP50 KO. In OCCC cells from clinical samples, Me-EBP50 and MYH9 were co-localized at the apical plasma membrane. Patients with a combination of Me-EBP50-high and MYH9-high scores had the best prognosis for overall and progression-free survival. Our data suggest that Me-EBP50 has tumor-suppressive effects through the establishment and maintenance of epithelial polarization. By contrast, loss of Me-EBP50 expression induces EMT-like phenotypes, probably due to MYH9 dysfunction; this results in increased cell mobility and enhanced CSC-like properties, which in turn promote OCCC progression.

Protein Biomarker Discovery Studies on Urinary sEV Fractions Separated with UF-SEC for the First Diagnosis and Detection of Recurrence in Bladder Cancer Patients

Urinary extracellular vesicles (EVs) are an attractive source of bladder cancer biomarkers. Here, a protein biomarker discovery study was performed on the protein content of small urinary EVs (sEVs) to identify possible biomarkers for the primary diagnosis and recurrence of non-muscle-invasive bladder cancer (NMIBC). The sEVs were isolated by ultrafiltration (UF) in combination with size-exclusion chromatography (SEC). The first part of the study compared healthy individuals with NMIBC patients with a primary diagnosis. The second part compared tumor-free patients with patients with a recurrent NMIBC diagnosis. The separated sEVs were in the size range of 40 to 200 nm. Based on manually curated high quality mass spectrometry (MS) data, the statistical analysis revealed 69 proteins that were differentially expressed in these sEV fractions of patients with a first bladder cancer tumor vs. an age- and gender-matched healthy control group. When the discriminating power between healthy individuals and first diagnosis patients is taken into account, the biomarkers with the most potential are MASP2, C3, A2M, CHMP2A and NHE-RF1. Additionally, two proteins (HBB and HBA1) were differentially expressed between bladder cancer patients with a recurrent diagnosis vs. tumor-free samples of bladder cancer patients, but their biological relevance is very limited.

Cytoplasmic EBP50 and elevated PARP1 are unfavorable prognostic factors in ovarian clear cell carcinoma

Patients with ovarian clear cell carcinoma (OCCC) experience frequent recurrence, which is most likely due to chemoresistance. We used shotgun proteomics analysis and identified upregulation of ezrin-binding phosphoprotein 50 (EBP50) in recurrent OCCC samples. Cytoplasmic and/or nuclear (Cyt/N), but not membranous, EBP50 immunoreactivity was significantly higher in recurrent OCCC as compared to that of primary tumors. OCCC cells expressing cytoplasmic EBP50 were significantly less susceptible to cisplatin (CDDP)-induced apoptosis compared to cells expressing membranous EBP50. Abrogation of resistance following knockdown of cytoplasmic EBP50 was accompanied by decreased XIAP and BCL2, increased BAX and increased caspase-3 cleavage. We found that poly (ADP-ribose) polymerase1 (PARP1), which is involved in DNA damage detection and repair, binds to EBP50 through its PDZ1 domain. CDDP treatment of cells expressing cytoplasmic (but not membranous) EBP50 increased nuclear PARP1 expression, whereas knockdown of EBP50 cells decreased PARP1 expression and activity following CDDP treatment. Finally, OCCC patients with a combination of Cyt/N EBP50 and high PARP1 score had worst the prognosis for overall and progression-free survival. Together, our data suggest that cytoplasmic EBP50 inhibits apoptosis and promotes OCCC survival through stabilization of PARP1 activity and modulation of the XIAP/BCL2/BAX axis. This may increase the likelihood of tumor recurrence, and we therefore suggest a combined analysis for EBP50 and PARP1 may have great utility in OCCC prediction and prognosis.

Nuclear expression of NHERF1/EBP50 in Clear Cell Renal Cell Carcinoma

The Na/H exchange regulatory factor 1 or Ezrin-radixin-moesin-binding phosphoprotein 50 (NHERF1/EBP50) is an adaptor protein implicated in the stabilization of molecular complexes linking extracellular signals with the cytoskeleton machinery. NHERF1 expression at the cell cortex is associated with the maintenance of adherent junction integrity in polarized epithelia. The role of NHERF1 in cancer depends on its localization within the cell, acting, in most cases, as a tumor suppressor when localized at the cell membrane, and as an oncogene, when expressed in the cytoplasm or the nucleus of cancer cells. The distribution of NHERF1 in renal cell carcinoma (RCC) has not been yet investigated. In this study, NHERF1 expression was examined by immunohistochemistry in papillary and clear cell RCC. We observed membranous staining in papillary RCC, whereas NHERF1 expression was nuclear and membranous in clear cell RCC. In comparison, NHERF1 immunohistochemistry in clear cell carcinomas of the ovary showed mainly nuclear staining. Our finding of the specific NHERF1 nuclear expression in clear cell carcinomas may help to elucidate the molecular changes that regulate its nuclear accumulation and to better understand its role in this cell compartment.

MINDIN Exerts Protumorigenic Actions on Primary Prostate Tumors via Downregulation of the Scaffold Protein NHERF-1

Advanced prostate cancer preferential metastasis to bone is associated with osteomimicry. MINDIN is a secreted matrix protein upregulated in prostate tumors that overexpresses bone-related genes during prostate cancer progression. Na+/H+ exchanger regulatory factor (NHERF-1) is a scaffold protein that has been involved both in tumor regulation and osteogenesis. We hypothesize that NHERF-1 modulation is a mechanism used by MINDIN to promote prostate cancer progression. We analyzed the expression of NHERF-1 and MINDIN in human prostate samples and in a premetastatic prostate cancer mouse model, based on the implantation of prostate adenocarcinoma TRAMP-C1 (transgenic adenocarcinoma of the mouse prostate) cells in immunocompetent C57BL/6 mice. The relationship between NHERF-1 and MINDIN and their effects on cell proliferation, migration, survival and osteomimicry were evaluated. Upregulation of MINDIN and downregulation of NHERF-1 expression were observed both in human prostate cancer samples and in the TRAMP-C1 model. MINDIN silencing restored NHERF-1 expression to control levels in the mouse model. Stimulation with MINDIN reduced NHERF-1 expression and triggered its mobilization from the plasma membrane to the cytoplasm in TRAMP-C1 cells. MINDIN-dependent downregulation of NHERF-1 promoted tumor cell migration and proliferation without affecting osteomimicry and adhesion. We propose that MINDIN downregulates NHERF-1 expression leading to promotion of processes involved in prostate cancer progression.

HDAC inhibition induces expression of scaffolding proteins critical for tumor progression in pediatric glioma: focus on EBP50 and IRSp53

BACKGROUND

Diffuse midline glioma (DMG) is a pediatric malignancy with poor prognosis. Most children die less than one year after diagnosis. Recently, mutations in histone H3 have been identified and are believed to be oncogenic drivers. Targeting this epigenetic abnormality using histone deacetylase (HDAC) inhibitors such as panobinostat (PS) is therefore a novel therapeutic option currently evaluated in clinical trials.

METHODS

BH3 profiling revealed engagement in an irreversible apoptotic process of glioma cells exposed to PS confirmed by annexin-V/propidium iodide staining. Using proteomic analysis of 3 DMG cell lines, we identified 2 proteins deregulated after PS treatment. We investigated biological effects of their downregulation by silencing RNA but also combinatory effects with PS treatment in vitro and in vivo using a chick embryo DMG model. Electron microscopy was used to validate protein localization.

RESULTS

Scaffolding proteins EBP50 and IRSp53 were upregulated by PS treatment. Reduction of these proteins in DMG cell lines leads to blockade of proliferation and migration, invasion, and an increase of apoptosis. EBP50 was found to be expressed in cytoplasm and nucleus in DMG cells, confirming known oncogenic locations of the protein. Treatment of glioma cells with PS together with genetic or chemical inhibition of EBP50 leads to more effective reduction of cell growth in vitro and in vivo.

CONCLUSION

Our data reveal a specific relation between HDAC inhibitors and scaffolding protein deregulation which might have a potential for therapeutic intervention for cancer treatment.

Alteration in the sensitivity to crizotinib by Na+/H+ exchanger regulatory factor 1 is dependent to its subcellular localization in ALK-positive lung cancers

Background

Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1) is an important scaffold protein participates in the modulation of a variety of intracellular signal pathways. NHERF1 was able to enhance the effects of chemo-drugs in breast and cervical cancer cells. Anaplastic lymphoma kinase (ALK) fusion mutations are validated molecules targeted therapy in lung cancers, where crizotinib can be used as the specific inhibitor to suppress tumor progression. However, due to the less frequent occurrence of ALK mutations and the complexity for factors to determine drug responses, the genes that could alter crizotinib sensitivity are unclear.

Methods

Both ALK-translocated and ALK-negative lung adenocarcinoma specimens in tissue sections were collected for immunohistochemistry. The possible mechanisms of NHERF1 and its role in the cell sensitivity to crizotinib were investigated using an ALK-positive and crizotinib-sensitive lung adenocarcinoma cell line H3122. Either a NHERF1 overexpression vector or agents for NHERF1 knockdown was used for crizotinib sensitivity measures, in association with cell viability and apoptosis assays.

Results

The expression level of NHERF1 in ALK-translocated NSCLC was significantly higher than that in other lung cancer tissues. NHERF1 expression in ALK positive lung cancer cells was regulated by ALK activities, and was in return able to alter the sensitivity to crizotinib. The function of NHERF1 to influence crizotinib sensitivity was depending on its subcellular distribution in cytosol instead of its nucleus localized form.

Conclusion

Ectopically overexpressed NHERF1 could be a functional protein for consideration to suppress lung cancers. The determination of NHERF1 levels in ALK positive NSCLC tissues might be useful to predict crizotinib resistance, especially by distinguishing cytosolic or nuclear localized NHERF1 for the overexpressed molecules.

Genetic and histologic spatiotemporal evolution of recurrent, multifocal, multicentric and metastatic glioblastoma

Glioblastoma is the most frequent and aggressive primary brain tumor, characterized by extensive brain invasion and rarely, systemic metastases. The pathogenesis of metastatic glioblastoma is largely unknown. We present the first integrated clinical/histologic/genetic analysis of 5 distinct brain and lung foci from a unique case of recurrent, multifocal, multicentric and metastatic glioblastoma. The initial right frontotemporal gliosarcoma received standard surgical/chemoradiation therapy and recurred 1.5 years later, co-occurring with three additional masses localized to the ipsilateral temporal lobe, cerebellum and lung. Synchronous metastatic lung carcinoma was suspected in this long-term smoker patient with family history of cancer. However, glioblastoma was confirmed in all tumors, although with different morphologic patterns, including ependymomatous and epithelioid. Genomic profiling revealed a germline FANCD2 variant of unknown significance, and a 4-gene somatic mutation signature shared by all tumors, consisting of TERT promoter and PTEN, RB1 and TP53 tumor suppressor mutations. Additional GRIN2A and ATM heterozygous mutations were selected in the cerebellar and lung foci, but were variably present in the supratentorial foci, indicating reduced post-therapeutic genetic evolution in brain foci despite morphologic variability. Significant genetic drift characterized the lung metastasis, likely explaining the known resistance of circulating glioblastoma cells to systemic seeding. MET overexpression was detected in the initial gliosarcoma and lung metastasis, possibly contributing to invasiveness. This comprehensive analysis sheds light on the temporospatial evolution of glioblastoma and underscores the importance of genetic testing for diagnosis and personalized therapy.

Mutation Status and Epithelial Differentiation Stratify Recurrence Risk in Chordoid Meningioma-A Multicenter Study with High Prognostic Relevance

Chordoid meningioma is a rare WHO grade II histologic variant. Its molecular alterations or their impact on patient risk stratification have not been fully explored. We performed a multicenter, clinical, histological, and genomic analysis of chordoid meningiomas from 30 patients (34 tumors), representing the largest integrated study to date. By NHERF1 microlumen immunohistochemical detection, three epithelial differentiation (ED) groups emerged: #1/fibroblastic-like, #2/epithelial-poorly-differentiated and #3/epithelial-well-differentiated. These ED groups correlated with tumor location and genetic profiling, with NF2 and chromatin remodeling gene mutations clustering in ED group #2, and TRAF7 mutations segregating in ED group #3. Mutations in LRP1B were found in the largest number of cases (36%) across ED groups #2 and #3. Pathogenic ATM and VHL germline mutations occurred in ED group #3 patients, conferring an aggressive or benign course, respectively. The recurrence rate significantly correlated with mutations in NF2, as single gene, and with mutations in chromatin remodeling and DNA damage response genes, as groups. The recurrence rate was very high in ED group #2, moderate in ED group #3, and absent in ED group #1. This study proposes guidelines for tumor recurrence risk stratification and practical considerations for patient management.

Prognostic and therapeutic implications of NHERF1 expression and regulation in colorectal cancer

BACKGROUND

Na⁺ /H⁺ exchanger regulatory factor 1 (NHERF1) has been implicated in the tumorigenesis of several cancer types and is a potential therapeutic target. The current study evaluated the relationship between NHERF1 expression and clinical outcome in colorectal cancer (CRC).

METHODS

NHERF1 expression was evaluated by immunohistochemistry in 167 patients with CRC primary tumors, 37 patients with no disease, and 27 patients with metastatic CRC (mCRC); and in the orthotopically implanted tumors in mice. NHERF1 expression was manipulated in CRC cells using inducible short hairpin RNAs to determine its biological functions.

RESULTS

High expression of NHERF1 correlated with CRC progression and metastasis, as well as significantly worse overall survival, recurrence-free survival, and disease-specific survival. Orthotopic implantation studies demonstrated increased NHERF1 expression in liver metastases. Treatment of CRC xenografts with insulin-like growth factor 1 receptor (IGF1R) inhibitors downregulated NHERF1 expression, indicating NHERF1 is downstream of IGF1R signaling. Knockdown of NHERF1 increased apoptosis and reduced X-linked inhibitor of apoptosis protein (XIAP) and survivin expression, indicating NHERF1 is critical for CRC cell survival.

CONCLUSION

NHERF1 expression levels correlated with worse prognosis in patients with CRC and plays a critical role in CRC cell survival. Together, our findings establish NHERF1 as a novel potential marker for increased risk of CRC-specific mortality and identify NHERF1 as an attractive therapeutic target for mCRC treatment.

ATPR-induced differentiation and G0/G1 phase arrest in acute promyelocytic leukemia by repressing EBP50/NCF1 complex to promote the production of ROS

Our previous study has demonstrated that 4-amino-2-trifluoromethyl-phenyl Retinate (ATPR) can induce human leukemia NB4 cells differentiation and G0/G1 phase arrest, but the underlying mechanism is still unclear. In this study, we used proteomics to screen differentially expressed protein profiles in NB4 cells before and after ATPR treatment in vitro. We analyzed the peptides digested from total cellular proteins by reverse phase LC-MS/MS and then performed label-free quantitative analysis. We found 27 significantly up-regulated proteins in the ATPR group compared to the control group. NCF1 was the most significantly changed protein. Immunoprecipitation and double immunofluorescent staining showed that EBP50 bind to NCF1. We further explored the potential molecular mechanism of EBP50/NCF1 complex in ATPR-induced differentiation and G0/G1 phase arrest. The results showed that ATPR remarkably reduced the expression of EBP50 in vivo and in vitro. Interestingly, the reduction of EBP50 contributed to ROS release by modulating the subcellular localization of NCF1. The reduction of EBP50 also contributed to G0/G1 phase arrest by inhibiting CyclinD1, CyclinA2 and CDK4, as well as promoting the differentiation of NB4 cells by increasing the expression of CD11b. Furthermore, we found that the overexpression of EBP50 restrained the effects of ATPR on differentiation and G0/G1 phase arrest in NB4 cells. These results suggest that ATPR-induced differentiation and G0/G1 phase arrest in acute promyelocytic leukemia (APL) by repressing EBP50/NCF1 complex to promote the production of ROS, and the results from in vivo experiments were consistent with those from in vitro studies. Therefore, our finding results suggest that EBP50 may be a new target for ATPR in the treatment of APL.

Repressing of NHERF1 inhibits liver cancer progression by promoting the production of ROS

NHERF1/EBP50 is a PDZ-scaffold protein initially identified as an organizer and modulator of transporters and channels at the apical side of epithelia via actin-binding ezrin-moesin-radixin proteins. Presently, hepatocellular carcinoma (HCC) is one of the most deadly cancers in the world and has no effective therapeutic strategies. In the present study, we attempted to explore the role of NHERF1 in regulating liver cancer progression. The results indicated that NHERF1 was significantly expressed in liver tumor samples compared to the corresponding adjacent normal tissues. HCC patients with low NHERF1 exhibited better survival rate. Additionally, repressing NHERF1 expression markedly down-regulated the cell proliferation. G0/G1 transition was highly induced by NHERF1 knockdown, accompanied with reduced expressions of Cyclin D1 and cyclin-dependent kinase 4 (CDK4), as well as the enhanced expression of p27, phosphatase and tensin homolog (PTEN) and p53. Moreover, NHERF1 suppression significantly induced apoptosis in liver cancer cells by promoting the activation of Caspase-3 and poly (ADP-ribose) polymerase (PARP). We also observed a remarkable increase of reactive oxygen species (ROS) production in NHERF1-knockdown cells, along with c-Jun-N-terminal kinase (JNK) phosphorylation. Importantly, suppressing ROS production abolished NHERF1 knockdown-induced JNK activation. Moreover, cell cycle-regulatory proteins meditated by NHERF1 knockdown in liver cancer cells were abrogated by the pre-treatment of ROS scavenger. Further, restraining ROS generation also diminished NHERF1 knockdown-induced apoptosis. In vivo, we also found that NHERF1 knockdown markedly reduced the tumor growth. In conclusion, the results suggested that NHERF1 played an essential role in regulating liver cancer progression, and repressing NHERF1 expression exhibited significant anticancer effects via the induction of G0/G1 phase arrest, apoptosis and ROS generation.

Epithelial differentiation with microlumen formation in meningioma: diagnostic utility of NHERF1/EBP50 immunohistochemistry

Meningioma is a primary brain tumor arising from the neoplastic transformation of meningothelial cells. Several histological variants of meningioma have been described. Here we show that NHERF1/EBP50, an adaptor protein required for structuring specialized polarized epithelia, can distinguish meningioma variants with epithelial differentiation. NHERF1 decorates the membrane of intracytoplasmic lumens and microlumens in the secretory variant, consistent with a previously described epithelial differentiation of this subtype. NHERF1 also labels microlumens in chordoid meningioma, an epithelial variant not previously known to harbor these structures, and ultrastructural analysis confirmed the presence of microlumens in this variant. NHERF1 associates with the ezrin-radixin-moesin (ERM)-NF2 cytoskeletal proteins, and moesin but not NF2 was detectable in the microlumens. In a meningioma series from 83 patients, NHERF1 revealed microlumens in 87.5% of the chordoid meningioma (n = 25) and meningioma with chordoid component (n = 7) cases, and in 100% of the secretory meningioma cases (n = 12). The most common WHO grade I meningioma variants lacked microlumens. Interestingly, 20% and 66.6% of WHO grades II (n = 20) and III (n = 3) meningiomas, respectively, showed microlumen-like NHERF1 staining of ultrastructural tight microvillar interdigitations, mainly in rhabdoid, papillary-like or sheeting areas, revealing a new subset of high grade meningiomas with epithelial differentiation. NHERF1 failed to detect microlumens in 12 additional cases of chordoid glioma of the 3rd ventricle, chordoma and chondrosarcoma, neoplasms that may mimic the histological appearance of chordoid meningioma. This study uncovers features of epithelial differentiation in meningioma and proposes NHERF1 immunohistochemistry as a method of discriminating chordoid meningioma from neoplasms with similar appearance.

Ezrin-Radixin-Moesin Binding Phosphoprotein 50: A Potential Novel Biomarker in Human Papilloma Virus-Associated Head and Neck Squamous Cell Carcinomas

High-risk human papilloma virus (HR-HPV) has increasingly been associated with head and neck squamous cell carcinoma (HNSCC), in particular oropharyngeal cancers. Ezrin-Radixin-Moesin Binding Phosphoprotein 50 (EBP50), a putative tumour suppressor, localises to the plasma membrane in suprabasal epithelium and to the cytoplasm in proliferative basal layers, and is a target for degradation by the HR-HPV E6 oncoprotein. The aim of this study was to investigate EBP50 protein expression patterns in HNSCC in a large Scottish cohort to determine if there was a correlation with HPV status and clinical outcomes. EBP50 expression patterns were assessed in 156 HNSCC including oropharyngeal (37.8%), laryngeal (24%), oral (19%) and other sites (18.5%), which were genotyped for presence of HR-HPV. HNSCC were generally negative for membranous EBP50. EBP50 expression was either cytoplasmic/absent, being 'predominantly cytoplasmic' in 76 (49%), 'weak/negligible cytoplasmic' in 44 (28%), 'strongly cytoplasmic' in 5 (3%), 'heterogeneous' in 26 (17%) and 'other' in 5 (3%) samples. Forty tumours (25%) were positive for HPV DNA, predominantly HR-HPV 16, and 44 (28%) were p16 positive. The majority of tumours (71%) with 'weak/negligible cytoplasmic' EBP50 expression originated in the oropharynx were more likely to have positive neck nodes, overexpression of p16 and positive tumour HR-HPV status (P < 0.001). Differences in EBP50 levels between oropharyngeal and non-oropharyngeal tumours may be linked to degradation of EBP50 by HR-HPV, and loss of EBP50 may therefore be a surrogate biomarker for HR-HPV infection in oropharyngeal tumours.

NHERF1 Between Promises and Hopes: Overview on Cancer and Prospective Openings

Na+/H+ exchanger regulatory factor 1 (NHERF1) is a scaffold protein, with two tandem PDZ domains and a carboxyl-terminal ezrin-binding (EB) region. This particular sticky structure is responsible for its interaction with different molecules to form multi-complexes that have a pivotal role in a lot of diseases. In particular, its involvement during carcinogenesis and cancer progression has been deeply analyzed in different tumors. The role of NHERF1 is not unique in cancer; its activity is connected to its subcellular localization. The literature data suggest that NHERF1 could be a new prognostic/predictive biomarker from breast cancer to hematological cancers. Furthermore, the high potential of this molecule as therapeutical target in different carcinomas is a new challenge for precision medicine. These evidences are part of a future view to improving patient clinical management, which should allow different tumor phenotypes to be treated with tailored therapies. This article reviews the biology of NHERF1, its engagement in different signal pathways and its involvement in different cancers, with a specific focus on breast cancer. It also considers NHERF1 potential role during inflammation related to most human cancers, designating new perspectives in the study of this "Janus-like" protein.

β-catenin knockdown promotes NHERF1-mediated survival of colorectal cancer cells: implications for a double-targeted therapy

Nuclear activated β-catenin plays a causative role in colorectal cancers (CRC) but remains an elusive therapeutic target. Using human CRC cells harboring different Wnt/β-catenin pathway mutations in APC/KRAS or β-catenin/KRAS genes, and both genetic and pharmacological knockdown approaches, we show that oncogenic β-catenin signaling negatively regulates the expression of NHERF1 (Na⁺/H⁺ exchanger 3 regulating factor 1), a PDZ-adaptor protein that is usually lost or downregulated in early dysplastic adenomas to exacerbate nuclear β-catenin activity. Chromatin immunoprecipitation (ChIP) assays demonstrated that β-catenin represses NHERF1 via TCF4 directly, while the association between TCF1 and the Nherf1 promoter increased upon β-catenin knockdown. To note, the occurrence of a cytostatic survival response in settings of single β-catenin-depleted CRC cells was abrogated by combining NHERF1 inhibition via small hairpin RNA (shRNA) or RS5517, a novel PDZ1-domain ligand of NHERF1 that prevented its ectopic nuclear entry. Mechanistically, dual NHERF1/β-catenin targeting promoted an autophagy-to-apoptosis switch consistent with the activation of Caspase-3, the cleavage of PARP and reduced levels of phospho-ERK1/2, Beclin-1, and Rab7 autophagic proteins compared with β-catenin knockdown alone. Collectively, our data unveil novel β-catenin/TCF-dependent mechanisms of CRC carcinogenesis, also offering preclinical proof of concept for combining β-catenin and NHERF1 pharmacological inhibitors as a mechanism-based strategy to augment apoptotic death of CRC cells refractory to current Wnt/β-catenin-targeted therapeutics.

NHERF1 regulates the progression of colorectal cancer through the interplay with VEGFR2 pathway

The oncogenic role of ectopic expression of Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1) was recently suggested in colorectal cancer, where it was implicated in playing a role in the tumor hypoxia microenvironment. Here we showed that a high level expression of NHERF1 was found in colorectal cancer tissues and that the expression of NHERF1 was positively correlated with VEGFR2 expression. The prognostic value of VEGFR2 expression in colorectal cancer relied on the expression of NHERF1. The up-regulation of NHERF1 induced by the exposure to hypoxia in colon cancer cells depended on the activation of VEGFR2 signaling. NHERF1 in turn inhibited the activation of VEGFR2 signaling which could be regulated by the interaction between NHERF1 and VEGFR2, resulting in the reduction of migration and invasion of colon cancer cells. These results suggest a dynamic interplay between NHERF1 and VEGFR2 signaling in colorectal cancer, which could explain the contribution of NHERF1 to the regulation of tumor cell responses to the hypoxia microenvironment.

β-catenin interaction with NHERF1 and RASSF1A methylation in metastatic colorectal cancer patients

There is an increasing need to identify new biomarkers in colorectal cancer (CRC) to further characterize this malignancy. β-catenin plays a central role in the Wnt signaling pathway. It also binds Na⁺/H⁺ exchanger regulating factor 1 (NHERF1) and interacts with the RAS-association domain family 1, isoform A (RASSF1A), but the mechanisms of this possible crosstalk are still not fully understood. In this study, we analyzed for the first time the different subcellular expression of β-catenin, NHERF1, and RASSF1A and their relationships with RASSF1A methylation in the progression of CRC. We assessed immunohistochemical expression and RASSF1A methylation in 51 patients with stage IV colorectal cancer. Biomarker expression analysis was carried out considering the tumor-adjacent normal tissue, the primary tumor, and the paired liver metastases. Regarding the tumor compartment, it was found that cytoplasmic β-catenin expression was positively correlated to membranous (r = 0.3002, p = 0.0323) and nuclear NHERF1 (r = 0.293, p = 0.0368). In the liver metastases, instead, we found a positive correlation of cytoplasmic and nuclear β-catenin expression with RASSF1A methylation (r = 0.4019, p = 0.0068 and r = 0.3194, p = 0.0345, respectively).

In conclusion, our results showed that β-catenin was the crucial protagonist in metastatic CRC through different effector proteins involved in this developing process. In tumor tissues, β-catenin was predominantly associated with NHERF1 in a dynamic context, while interestingly in liver metastases, we noted an increase of its oncogenic function through RASSF1A inactivation.

The cellular distribution of Na+/H+ exchanger regulatory factor 1 is determined by the PDZ-I domain and regulates the malignant progression of breast cancer

The oncogenic role of ectopic expression of Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1) was recently suggested. Here, we show that NHERF1 was upregulated in high grades compared with low grades. Increased NHERF1 expression was correlated with poor prognosis and poor survival. NHERF1 expression was higher in the nucleus of cancer cells than in contiguous non- mammary epithelial cells. A novel mutation, namely NHERF1 Y24S, was identified in human breast cancer tissues and shown to correspond to a conserved residue in the PDZ-I domain of NHERF1. Truncation and mutation of the PDZ-I domain of NHERF1 increased the nuclear distribution of the NHERF1 protein, and this redistribution was associated with the malignant phenotype of breast cancer cells, including growth, migration, and adhesion. The present results suggest a role for NHERF1 in the progression of breast cancer mediated by the nuclear distribution of the NHERF1 protein, as determined by the truncation or key site mutation of the PDZ-I domain.

Hierarchical clustering analysis identifies metastatic colorectal cancers patients with more aggressive phenotype

A large percentage of metastatic colorectal cancer (mCRC) patients presents metastasis at the time of diagnosis. In the last years, great efforts have been made in the treatment of these patients with the identification of different phenotypes playing a key role in the definition of new systemic therapies. Unsupervised hierarchical clustering analysis (HCA) was performed considering the clinicopathological characteristics of 51 mCRCs. Using immunohistochemistry on tissue microarrays, we assessed the expression of β-catenin, NHERF1, RASSF1A, TWIST1, HIF-1α proteins in tumors and paired liver metastases. We also analyzed RASSF1A methylation status on the samples of the same patients. HCA distinguished Group 1 and Group 2 characterized by different clinicopathological features. Group 1 was characterized by higher number of positive lymph nodes (p=0.0139), poorly differentiated grade (p<0.0001) and high extent of tumor spread (p=0.0053) showing a more aggressive phenotype compared to Group 2. In both Groups, we found a common "basal" condition with a higher level of nuclear TWIST1 (p<0.0001 and cytoplasmic β-catenin (p<0.0001) in tumors than in paired liver metastases. Furthermore, the Group 1 was also characterized by RASSF1A hypermethylation (p<0.0001) and nuclear HIF-1α overexpression (p=0.0354) in paired liver metastases than in tumors. In conclusion, HCA identifies mCRC patients with a more aggressive phenotype. Moroever, our results support the important contribution to the progression of the disease of RASSF1A methylation and the oncogenic role of HIF-1α in these patients. These evidences, should provide relevant information concerning the biology of this tumor and, as a consequence, potential new systemic therapeutic approaches.

NHERF1/EBP50 Suppresses Wnt-β-Catenin Pathway-Driven Intestinal Neoplasia

NHERF1/EBP50, an adaptor molecule that interacts with β-catenin, YAP, and PTEN, has been recently implicated in the progression of various human malignancies, including colorectal cancer. We report here that NHERF1 acts as a tumor suppressor in vivo for intestinal adenoma development. NHERF1 is highly expressed at the apical membrane of mucosa intestinal epithelial cells (IECs) and serosa mesothelial cells. NHERF1-deficient mice show overall longer small intestine and colon that most likely could be attributed to a combination of defects, including altered apical brush border of absorbtive IECs and increased number of secretory IECs. NHERF1 deficiency in Apc(Min/+) mice resulted in significantly shorter animal survival due to markedly increased tumor burden. This resulted from a moderate increase of the overall tumor density, more pronounced in females than males, and a massive increase in the number of large adenomas in both genders. The analysis of possible pathways controlling tumor size showed upregulation of Wnt-β-catenin pathway, higher expression of unphosphorylated YAP, and prominent nuclear expression of cyclin D1 in NHERF1-deficient tumors. Similar YAP changes, with relative decrease of phosphorylated YAP and increase of nuclear YAP expression, were observed as early as the adenoma stages in the progression of human colorectal cancer. This study discusses a complex role of NHERF1 for intestinal morphology and presents indisputable evidence for its in vivo tumor suppressor function upstream of Wnt-β-catenin and Hippo-YAP pathways.

NHERF1 together with PARP1 and BRCA1 expression as a new potential biomarker to stratify breast cancer patients

It has been recognized that Na⁺/H⁺ Exchanger Regulatory Factor 1 (NHERF1) in breast cancer (BC) acts as a tumor suppressor or as an oncogenic protein, depending on its subcellular localization. This study aims to correlate NHERF1 expression to BRCA1 and PARP1 proteins, to investigate their relationship, and their biological and clinical significance. Using immunohistochemistry on tissue microarrays, we evaluated subcellular NHERF1, BRCA1 and PARP1 expression in 308 BCs including a subgroup (n=80) of triple negative BCs (TNBCs). Herein, we show that nuclear NHERF1 (nNHERF1) expression was significantly associated with nuclear BRCA1 (nBRCA1) expression (p=0.0008), and an association was also found between nuclear PARP1 (nPARP1) and nBRCA1 (p<0.0001). Cytoplasmic NHERF1 (cNHERF1) was correlated to nPARP1 (p<0.0001). Survival analyses showed that the patients with positive nPARP1 and nNHERF1 tended toward a shorter 5-year overall survival (OS) (p=0.057). In TNBCs, the association between nBRCA1 and nPARP1 was maintained (p<0.0001), and an association between nNHERF1 and nPARP1 was observed (p=0.010). Univariate analysis revealed that TNBCs with positive cNHERF1 and nPARP1 had a shorter 5-year OS (p=0.048).

Our data suggest that NHERF1 could be a new potential biomarker in combination with PARP1 and BRCA1 expression to stratify BC patients. In particular, in TNBCs, cNHERF1 associated with nPARP1 expression identified a patient subgroup with a shorter survival, for whom it may be useful to develop novel therapeutic strategies.

Roles of NHERF Family of PDZ-Binding Proteins in Regulating GPCR Functions

Multicellular organisms are equipped with an array of G-protein-coupled receptors (GPCRs) that mediate cell-cell signaling allowing them to adapt to environmental cues and ultimately survive. This is mechanistically possible through complex intracellular GPCR machinery that encompasses a vast network of proteins. Within this network, there is a group called scaffolding proteins that facilitate proper localization of signaling proteins for a quick and robust GPCR response. One protein family within this scaffolding group is the PSD-95/Dlg/ZO-1 (PDZ) family which is important for GPCR localization, internalization, recycling, and downstream signaling. Although the PDZ family of proteins regulate the functions of several receptors, this chapter focuses on a subfamily within the PDZ protein family called the Na⁺/H⁺ exchanger regulatory factors (NHERFs). Here we extensively review the predominantly characterized roles of NHERFs in renal phosphate absorption, intestinal ion regulation, cancer progression, and immune cell functions. Finally, we discuss the future perspectives and possible clinical application of targeting NHERFs in several disorders.

Dynamic relocalization of NHERF1 mediates chemotactic migration of ovarian cancer cells toward lysophosphatidic acid stimulation

NHERF1/EBP50 (Na⁺/H⁺ exchanger regulating factor 1; Ezrin-binding phosphoprotein of 50 kDa) organizes stable protein complexes beneath the apical membrane of polar epithelial cells. By contrast, in cancer cells without any fixed polarity, NHERF1 often localizes in the cytoplasm. The regulation of cytoplasmic NHERF1 and its role in cancer progression remain unclear. In this study, we found that, upon lysophosphatidic acid (LPA) stimulation, cytoplasmic NHERF1 rapidly translocated to the plasma membrane, and subsequently to cortical protrusion structures, of ovarian cancer cells. This movement depended on direct binding of NHERF1 to C-terminally phosphorylated ERM proteins (cpERMs). Moreover, NHERF1 depletion downregulated cpERMs and further impaired cpERM-dependent remodeling of the cell cortex, suggesting reciprocal regulation between these proteins. The LPA-induced protein complex was highly enriched in migratory pseudopodia, whose formation was impaired by overexpression of NHERF1 truncation mutants. Consistent with this, NHERF1 depletion in various types of cancer cells abolished chemotactic cell migration toward a LPA gradient. Taken together, our findings suggest that the high dynamics of cytosolic NHERF1 provide cancer cells with a means of controlling chemotactic migration. This capacity is likely to be essential for ovarian cancer progression in tumor microenvironments containing LPA.

NHERF1 inhibits proliferation of triple-negative breast cancer cells by suppressing GPER signaling

G protein-coupled estrogen receptor (GPER) signaling is activated in triple-negative breast cancer (TNBC); however, the detailed mechanisms of its regulation remain unclear. The present study aimed to elucidate the molecular mechanisms involved in GPER activation in TNBC. In MDA-MB-231 cells, a TNBC cell line, NHERF1 interaction with GPER was verified by co-immunoprecipitation and immunofluorescent staining assays. Overexpression of NHERF1 in MDA-MB-231 cells inhibited GPER-mediated proliferation and phosphorylation of ERK1/2 and Akt. Furthermore, NHERF1 expression levels were negatively correlated with the gene signatures of GPER activation, ERK1/2 and Akt signaling, and cell proliferation in early stage of TNBC tumors from the TCGA data set. Taken together, NHERF1 inhibited the activation of GPER-mediated signaling and suppressed the proliferation of triple-negative breast cancer cells. Loss of NHERF1 expression may play a pivotal role in the early stage of TNBC carcinogenesis.

Role of the PDZ-scaffold protein NHERF1/EBP50 in cancer biology: from signaling regulation to clinical relevance

The transmission of cellular information requires fine and subtle regulation of proteins that need to interact in a coordinated and specific way to form efficient signaling networks. The spatial and temporal coordination relies on scaffold proteins. Thanks to protein interaction domains such as PDZ domains, scaffold proteins organize multiprotein complexes enabling the proper transmission of cellular information through intracellular networks. NHERF1/EBP50 is a PDZ-scaffold protein that was initially identified as an organizer and regulator of transporters and channels at the apical side of epithelia through actin-binding ezrin-moesin-radixin proteins. Since, NHERF1/EBP50 has emerged as a major regulator of cancer signaling network by assembling cancer-related proteins. The PDZ-scaffold EBP50 carries either anti-tumor or pro-tumor functions, two antinomic functions dictated by EBP50 expression or subcellular localization. The dual function of NHERF1/EBP50 encompasses the regulation of several major signaling pathways engaged in cancer, including the receptor tyrosine kinases PDGFR and EGFR, PI3K/PTEN/AKT and Wnt-β-catenin pathways.

Nano-liquid Chromatography-orbitrap MS-based Quantitative Proteomics Reveals Differences Between the Mechanisms of Action of Carnosic Acid and Carnosol in Colon Cancer Cells

Carnosic acid (CA) and carnosol (CS) are two structurally related diterpenes present in rosemary herb (Rosmarinus officinalis). Although several studies have demonstrated that both diterpenes can scavenge free radicals and interfere in cellular processes such as cell proliferation, they may not necessarily exert the same effects at the molecular level. In this work, a shotgun proteomics study based on stable isotope dimethyl labeling (DML) and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) has been performed to identify the relative changes in proteins and to gain some light on the specific molecular targets and mechanisms of action of CA and CS in HT-29 colon cancer cells. Protein profiles revealed that CA and CS induce different Nrf2-mediated response. Furthermore, examination of our data revealed that each diterpene affects protein homeostasis by different mechanisms. CA treatment induces the expression of proteins involved in the unfolded protein response in a concentration dependent manner reflecting ER stress, whereas CS directly inhibits chymotrypsin-like activity of the 20S proteasome. In conclusion, the unbiased proteomics-wide method applied in the present study has demonstrated to be a powerful tool to reveal differences on the mechanisms of action of two related bioactive compounds in the same biological model.

Similar expression pattern of NHERF1 and EZRIN in papillary but not in solid areas of human serous ovarian carcinomas

NHERF1 is an adaptor protein expressed in the apical membrane of polarized epithelia, which interacts with the EZRIN-Radixin-Moesin (ERM) family of proteins connecting signaling pathways to the cell cytoskeleton. NHERF1 and EZRIN cooperate in the maintenance of the apical microvilli in polarized epithelial cells. In several types of cancers, NHERF1 and EZRIN are displaced from the apical compartment to the cytoplasm and nuclei of cancer cells. At the present, the distribution of NHERF1 in ovarian tumors is not well known. In this study, NHERF1 expression was examined by immunohistochemistry in cyst adenofibromas, serous borderline tumors, and serous ovarian carcinomas. We observed a strong staining of NHERF1 and EZRIN at the membrane level of borderline tumors and areas of papillary structures in ovarian carcinomas. In tumors without papillary structures and compact structure, NHERF1 was exclusively expressed in the apical pole of the cells at the edges of the clefts of luminal spaces. In contrast, positive expression of EZRIN was found in the membrane of tumor cells within the solid tumor where NHERF1 was not expressed. In summary, this study shows, for the first time, the distribution of NHERF1 in ovarian cancer and reveals a different regulation of NHERF1 and EZRIN expression in ovarian tumors which represents the complexity of the molecular changes of this disease.

Binding of EBP50 to Nox organizing subunit p47phox is pivotal to cellular reactive species generation and altered vascular phenotype

Despite numerous reports implicating NADPH oxidases (Nox) in the pathogenesis of many diseases, precise regulation of this family of professional reactive oxygen species (ROS) producers remains unclear. A unique member of this family, Nox1 oxidase, functions as either a canonical or hybrid system using Nox organizing subunit 1 (NoxO1) or p47(phox), respectively, the latter of which is functional in vascular smooth muscle cells (VSMC). In this manuscript, we identify critical requirement of ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50; aka NHERF1) for Nox1 activation and downstream responses. Superoxide (O2 (•-)) production induced by angiotensin II (AngII) was absent in mouse EBP50 KO VSMC vs. WT. Moreover, ex vivo incubation of aortas with AngII showed a significant increase in O2 (•-) in WT but not EBP50 or Nox1 nulls. Similarly, lipopolysaccharide (LPS)-induced oxidative stress was attenuated in femoral arteries from EBP50 KO vs. WT. In silico analyses confirmed by confocal microscopy, immunoprecipitation, proximity ligation assay, FRET, and gain-/loss-of-function mutagenesis revealed binding of EBP50, via its PDZ domains, to a specific motif in p47(phox) Functional studies revealed AngII-induced hypertrophy was absent in EBP50 KOs, and in VSMC overexpressing EBP50, Nox1 gene silencing abolished VSMC hypertrophy. Finally, ex vivo measurement of lumen diameter in mouse resistance arteries exhibited attenuated AngII-induced vasoconstriction in EBP50 KO vs. WT. Taken together, our data identify EBP50 as a previously unidentified regulator of Nox1 and support that it promotes Nox1 activity by binding p47(phox) This interaction is pivotal for agonist-induced smooth muscle ROS, hypertrophy, and vasoconstriction and has implications for ROS-mediated physiological and pathophysiological processes.

Vitamin D3 suppresses morphological evolution of the cribriform cancerous phenotype

Development of cribriform morphology (CM) heralds malignant change in human colon but lack of mechanistic understanding hampers preventive therapy. This study investigated CM pathobiology in three-dimensional (3D) Caco-2 culture models of colorectal glandular architecture, assessed translational relevance and tested effects of 1,25(OH)2D3,theactive form of vitamin D. CM evolution was driven by oncogenic perturbation of the apical polarity (AP) complex comprising PTEN, CDC42 and PRKCZ (phosphatase and tensin homolog, cell division cycle 42 and protein kinase C zeta). Suppression of AP genes initiated a spatiotemporal cascade of mitotic spindle misorientation, apical membrane misalignment and aberrant epithelial configuration. Collectively, these events promoted "Swiss cheese-like" cribriform morphology (CM) comprising multiple abnormal "back to back" lumens surrounded by atypical stratified epithelium, in 3D colorectal gland models. Intestinal cancer driven purely by PTEN-deficiency in transgenic mice developed CM and in human CRC, CM associated with PTEN and PRKCZ readouts. Treatment of PTEN-deficient 3D cultures with 1,25(OH)2D3 upregulated PTEN, rapidly activated CDC42 and PRKCZ, corrected mitotic spindle alignment and suppressed CM development. Conversely, mutationally-activated KRAS blocked1,25(OH)2D3 rescue of glandular architecture. We conclude that 1,25(OH)2D3 upregulates AP signalling to reverse CM in a KRAS wild type (wt), clinically predictive CRC model system. Vitamin D could be developed as therapy to suppress inception or progression of a subset of colorectal tumors.

NHERF1/EBP50 and NF2 as diagnostic markers for choroid plexus tumors

The adaptor protein NHERF1 (Na/H exchanger-3 regulatory factor-1) and its associated ezrin-radixin-moesin-merlin/neurofibromin-2 (ERM-NF2) family proteins are required for epithelial morphogenesis and have been implicated in cancer progression. NHERF1 is expressed in ependymal cells and constitutes a highly sensitive diagnostic marker for ependymoma, where it labels membrane polarity structures. Since NHERF1 and ERM-NF2 proteins show polarized expression in choroid plexus (CP) cells, we tested their diagnostic utility in CP neoplasms. NHERF1 immunohistochemistry in 43 adult and pediatric tumors with papillary morphology revealed strong apical plasma membrane staining in CP papilloma (WHO grade I) and cytoplasmic expression in CP carcinoma (WHO grade III). Ezrin and moesin showed similar but less distinctive staining. NHERF1 also labeled papillary tumors of the pineal region in a microlumen and focal apical membrane pattern, suggestive of a transitional morphology between CP papilloma and ependymoma. CP tumors of all grades could be differentiated from metastatic carcinomas with papillary architecture by NF2, which showed polarized membranous staining in CP tumors. NHERF1 and NF2 immunohistochemistry showed enhanced sensitivity and specificity for CP tumors compared to commonly used markers, including cytokeratins and Kir7.1, emerging as reliable diagnostic tools for the differential diagnosis of papillary tumors of the central nervous system.

Deletion of Na+/H+ exchanger regulatory factor 2 represses colon cancer progress by suppression of Stat3 and CD24

The Na(+)/H(+) exchanger regulatory factor (NHERF) family of proteins is scaffolds that orchestrate interaction of receptors and cellular proteins. Previous studies have shown that NHERF1 functions as a tumor suppressor. The goal of this study is to determine whether the loss of NHERF2 alters colorectal cancer (CRC) progress. We found that NHERF2 expression is elevated in advanced-stage CRC. Knockdown of NHERF2 decreased cancer cell proliferation in vitro and in a mouse xenograft tumor model. In addition, deletion of NHERF2 in Apc(Min/+) mice resulted in decreased tumor growth in Apc(Min/+) mice and increased lifespan. Blocking NHERF2 interaction with a small peptide designed to bind the second PDZ domain of NHERF2 attenuated cancer cell proliferation. Although NHERF2 is known to facilitate the effects of lysophosphatidic acid receptor 2 (LPA2), transcriptome analysis of xenograft tumors revealed that NHERF2-dependent genes largely differ from LPA2-regulated genes. Activation of β-catenin and ERK1/2 was mitigated in Apc(Min/+);Nherf2(-/-) adenomas. Moreover, Stat3 phosphorylation and CD24 expression levels were suppressed in Apc(Min/+);Nherf2(-/-) adenomas. Consistently, NHERF2 knockdown attenuated Stat3 activation and CD24 expression in colon cancer cells. Interestingly, CD24 was important in the maintenance of Stat3 phosphorylation, whereas NHERF2-dependent increase in CD24 expression was blocked by inhibition of Stat3, suggesting that NHERF2 regulates Stat3 phosphorylation through a positive feedback mechanism between Stat3 and CD24. In summary, this study identifies NHERF2 as a novel oncogenic protein and a potential target for cancer treatment. NHERF2 potentiates the oncogenic effects in part by regulation of Stat3 and CD24.

Mining for Candidate Genes Related to Pancreatic Cancer Using Protein-Protein Interactions and a Shortest Path Approach

Pancreatic cancer (PC) is a highly malignant tumor derived from pancreas tissue and is one of the leading causes of death from cancer. Its molecular mechanism has been partially revealed by validating its oncogenes and tumor suppressor genes; however, the available data remain insufficient for medical workers to design effective treatments. Large-scale identification of PC-related genes can promote studies on PC. In this study, we propose a computational method for mining new candidate PC-related genes. A large network was constructed using protein-protein interaction information, and a shortest path approach was applied to mine new candidate genes based on validated PC-related genes. In addition, a permutation test was adopted to further select key candidate genes. Finally, for all discovered candidate genes, the likelihood that the genes are novel PC-related genes is discussed based on their currently known functions.

A novel splicing mutation in the SLC9A3R1 gene in tumors from ovarian cancer patients

The aim of the present study was to investigate novel molecular markers that could improve the diagnosis of ovarian cancer patients or be of predictive value. The sequence of the sodium-hydrogen antiporter 3 regulator 1 (SLC9A3R1) gene that codes for the PDZ2 motif of the Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1) protein was analyzed. Changes in migration and cell transformation, and alterations of growth factor signaling pathways have been described in cells lacking endogenous NHERF1 or expressing an isoform lacking the function of the PDZ2 domain. Exons 2 and 3, together with flanking intronic sequences of the SLC9A3R1 gene, were amplified and bi-directionally sequenced in 31 primary tumor samples from epithelial ovarian cancer patients. In total, 3 different previously undescribed mutations were detected in 8 out of 31 serous adenocarcinoma tumor samples (25.8%). Bioinformatics analysis predicted a significant effect in the splicing process as a result of the mutations that could disrupt the NHERF1 PDZ2 domain. Point mutations in consensus splicing recognition are a major cause of the splicing defects that are found in several diseases, including cancer. It has previously been shown that a lack of exon 2 and disruption of the PDZ2 domain contribute to cell transformation and leads to modifications in the physiological regulation of the conformational state of NHERF1. Further studies in bigger groups of ovarian cancer patients will determine the importance of this mutation in disease progression and patient survival.

The potential predictive role of nuclear NHERF1 expression in advanced gastric cancer patients treated with epirubicin/oxaliplatin/capecitabine first line chemotherapy

Cellular resistance in advanced gastric cancer (GC) might be related to function of multidrug resistance (MDR) proteins. The adaptor protein NHERF1 (Na(+)/H(+) exchanger regulatory factor) is an important player in cancer progression for a number of solid malignancies, even if its role to develop drug resistance remains uncertain. Herein, we aimed to analyze the potential association between NHERF1 expression and P-gp, sorcin and HIF-1α MDR-related proteins in advanced GC patients treated with epirubicin/oxaliplatin/capecitabine (EOX) chemotherapy regimen, and its relation to response. Total number of 28 untreated patients were included into the study. Expression and subcellular localization of all proteins were assessed by immunohistochemistry on formalin-fixed paraffin embedded tumor samples. We did not found significant association between NHERF1 expression and the MDR-related proteins. A trend was observed between positive cytoplasmic NHERF1 (cNHERF1) expression and negative nuclear HIF-1α (nHIF-1α) expression (68.8% versus 31.3% respectively, P = 0.054). However, cytoplasmic P-gp (cP-gp) expression was positively correlated with both cHIF-1α and sorcin expression (P = 0.011; P = 0.002, respectively). Interestingly, nuclear NHERF1 (nNHERF1) staining was statistically associated with clinical response. In detail, 66.7% of patients with high nNHERF1 expression had a disease control rate, while 84.6% of subjects with negative nuclear expression of the protein showed progressive disease (P = 0.009). Multivariate analysis confirmed a significant correlation between nNHERF1 and clinical response (OR 0.06, P = 0.019). These results suggest that nuclear NHERF1 could be related to resistance to the EOX regimen in advanced GC patients, identifying this marker as a possible independent predictive factor.

Minireview: Role of intracellular scaffolding proteins in the regulation of endocrine G protein-coupled receptor signaling

The majority of hormones stimulates and mediates their signal transduction via G protein-coupled receptors (GPCRs). The signal is transmitted into the cell due to the association of the GPCRs with heterotrimeric G proteins, which in turn activates an extensive array of signaling pathways to regulate cell physiology. However, GPCRs also function as scaffolds for the recruitment of a variety of cytoplasmic protein-interacting proteins that bind to both the intracellular face and protein interaction motifs encoded by GPCRs. The structural scaffolding of these proteins allows GPCRs to recruit large functional complexes that serve to modulate both G protein-dependent and -independent cellular signaling pathways and modulate GPCR intracellular trafficking. This review focuses on GPCR interacting PSD95-disc large-zona occludens domain containing scaffolds in the regulation of endocrine receptor signaling as well as their potential role as therapeutic targets for the treatment of endocrinopathies.

PRL-3 Promotes the Malignant Progression of Melanoma via Triggering Dephosphorylation and Cytoplasmic Localization of NHERF1

Phosphatase of regenerating liver-3 (PRL-3) has been reported to have a critical role in metastatic progression of cancers. Here, we investigate how PRL-3 increases the malignant degree of melanoma cells. The expression of PRL-3 increased gradually during the malignant progression of melanoma. The phosphorylation of Akt was elevated in highly malignant melanoma cells, which was accompanied by a decrease in nuclear phosphatase and tensin homolog (PTEN). The phosphorylation of NHERF1 in the serine site was regulated by PRL-3 and showed cytoplasmic translocation upon dephosphorylation, which resulted in a decrease in nuclear PTEN. The co-translocation of NHERF1 and PTEN from the nucleus to the cytoplasm was observed during the malignant progression of melanoma cells. Tumor growth was inhibited significantly, and the survival was prolonged upon knockdown of cytoplasmic NHERF1 in B16BL6 cells prior to the inoculation into mice. Taken together, to our knowledge previously unreported, we have identified NHERF1 as a potential substrate of PRL-3. Its phosphorylation status as well as its change in cellular localization and association with PTEN correlated with the malignant progression of melanoma. Our data provide an explanation for how PRL-3 promotes the malignant progression of melanoma, as well as a diagnostic marker or therapeutic target for malignant melanoma.

NHERF1/EBP50 is an organizer of polarity structures and a diagnostic marker in ependymoma

NHERF1/EBP50, an adaptor protein required for epithelial morphogenesis, has been implicated in the progression of various human malignancies. NHERF1-deficient mice have intestinal brush border structural defects and we report here that they also have disorganized ependymal cilia with development of non-obstructive hydrocephalus. Examination of mouse and human brain tissues revealed highest NHERF1 expression at the apical plasma membrane of ependymal cells. In ependymal tumors, NHERF1 expression was retained in polarized membrane structures, such as microlumens, rosettes and canals, where it co-localized with some of its ligands, such as moesin and PTEN. Analysis of a comprehensive panel of 113 tumors showed robust NHERF1 labeling of microlumens in 100% of ependymomas, subependymomas, and pediatric anaplastic ependymomas, and in 67% of adult anaplastic ependymomas. NHERF1 staining was present in 35% of ependymoma cases that lacked reactivity for EMA, the routine immunohistochemical marker used for ependymoma diagnosis. NHERF1 labeling of microlumens was either absent or rarely seen in other types of brain tumors analyzed, denoting NHERF1 as a reliable diagnostic marker of ependymal tumors. Anaplastic foci and a subset of adult anaplastic ependymomas showed complete absence of NHERF1-labeled polarity structures, consistent with a loss of differentiation in these aggressive tumors. These data highlight a role for NHERF1 in ependymal morphogenesis with direct application to the diagnosis of ependymal tumors.

NHERF1/EBP50 controls morphogenesis of 3D colonic glands by stabilizing PTEN and ezrin-radixin-moesin proteins at the apical membrane

Na(+)/H(+) exchanger 3 regulating factor 1/ezrin-radixin-moesin (ERM)-binding phosphoprotein 50 (NHERF1/EBP50), an adaptor molecule that interacts with the ERM-neurofibromatosis type 2 family of cytoskeletal proteins through its ERM-binding region and with phosphatase and tensin homolog (PTEN) and β-catenin through its PDZ domains, has been recently implicated in the progression of various human malignancies, including colorectal cancer (CRC). We report here that NHERF1 controls gland morphogenesis, as demonstrated in three-dimensional (3D) human intestinal glands developing from a single nonpolarized cell. Starting from the early two-cell developmental stage, NHERF1 concentrates at the cellular interface in a central membrane disc that marks the apical pole delimiting the forming lumen. NHERF1 depletion leads to severe disruption of the apical-basal polarity, with formation of enlarged and distorted cell spheroids devoid of a central lumen. This characteristic and the increased number of mitoses in NHERF1-depleted spheroids, including multipolar ones, mimic high-grade dysplasia lesions observed in CRC progression. NHERF1 ERM-binding or PDZ-domain mutants fail to localize apically and impair gland formation most likely by outcompeting endogenous ligands, with the latter mutant completely aborting gland development. Examination of NHERF1 ligands showed that even if both ezrin and moesin colocalized with NHERF1 at the apical membrane, moesin but not ezrin depletion disrupted morphogenesis similarly to NHERF1. NHERF1 depletion resulted also in membrane displacement of PTEN and nuclear translocation of β-catenin, events contributing to polarity loss and increased proliferation. These findings reveal an essential role of NHERF1 in epithelial morphogenesis and polarity and validate this 3D system for modeling the molecular changes observed in CRC.

PHLPP2 suppresses the NF-κB pathway by inactivating IKKβ kinase

The NF-κB growth pathway is constitutively activated in many cancers but its activation mechanism is unclear in most cases. We show that PHLPP2 interacts with IKKβ kinase, decreases its phosphorylation and the subsequent NF-κB activation in cancer cells. PHLPP2 is progressively lost in glioma and colorectal cancer and acts as a bona fide tumor suppressor, depending on IKKβ expression in cells. Physiologically, IKKβ activation by growth factors requires the formation of the Bcl10-MALT1 ubiquitin-ligase complex leading to NEMO/IKKγ non-degradative ubiquitination and IKKβ phosphorylation. PHLPP2 opposes the formation of this complex through interaction with Bcl10 and competitive displacement of MALT1 from Bcl10. Conversely, PHLPP2 loss enhances Bcl10-MALT1 complex formation, NEMO ubiquitination and subsequent IKKβ phosphorylation, resulting in increased NF-κB-dependent transcription of multiple target genes. Our results reveal PHLPP2 as a new biomarker of cancer progression, and implicate it as major negative regulator of NF-κB signaling.

Designing a novel high-throughput AlphaLISA assay to quantify plasma NHERF1 as a non-small cell lung cancer biomarker

A novel amplified luminescent proximity homogeneous immunoassay (AlphaLISA) has been developed and validated for the quantification of NHERF1 in human plasma.

SMO expression in colorectal cancer: associations with clinical, pathological, and molecular features

BACKGROUND

Smoothened, frizzled family receptor (SMO) is an important component of the hedgehog signaling pathway, which has been implicated in various human carcinomas. However, clinical, molecular, and prognostic associations of SMO expression in colorectal cancer remain unclear.

METHODS

Using a database of 735 colon and rectal cancers in the Nurse's Health Study and the Health Professionals Follow-up Study, we examined the relationship of tumor SMO expression (assessed by immunohistochemistry) to prognosis, and to clinical, pathological, and tumor molecular features, including mutations of KRAS, BRAF, and PIK3CA, microsatellite instability, CpG island methylator phenotype (CIMP), LINE-1 methylation, and expression of phosphorylated AKT and CTNNB1.

RESULTS

SMO expression was detected in 370 tumors (50 %). In multivariate logistic regression analysis, SMO expression was independently inversely associated with phosphorylated AKT expression [odds ratio (OR) 0.48; 95 % confidence interval (CI) 0.34-0.67] and CTNNB1 nuclear localization (OR 0.48; 95 % CI 0.35-0.67). SMO expression was not significantly associated with colorectal cancer-specific or overall survival. However, in CIMP-high tumors, but not CIMP-low/0 tumors, SMO expression was significantly associated with better colorectal cancer-specific survival (log-rank P = 0.012; multivariate hazard ratio, 0.36; 95 % CI 0.13-0.95; P interaction = 0.035, for SMO and CIMP status).

CONCLUSIONS

Our data reveal novel potential associations between the hedgehog, the WNT/CTNNB1, and the PI3K (phosphatidylinositol-4,5-bisphosphonate 3-kinase)/AKT pathways, supporting pivotal roles of SMO and hedgehog signaling in pathway networking. SMO expression in colorectal cancer may interact with tumor CIMP status to affect patient prognosis, although confirmation by future studies is needed.

EBP50 inhibits the migration and invasion of human breast cancer cells via LIMK/cofilin and the PI3K/Akt/mTOR/MMP signaling pathway

The scaffold protein ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50, also known as NHERF1 or NHERF) inhibits epidermal growth factor (EGF)-induced breast cancer cell proliferation after 3 days by blocking EGF receptor (EGFR) phosphorylation. The loss of EBP50 stimulates EGFR activity and induces the appearance of epithelial-to-mesenchymal transition phenotypic features in biliary cancer cells. However, the involvement of EBP50 in breast cancer migration and invasion remains unknown. We report that EBP50 inhibits the migration and invasion of breast cancer cells by inhibiting the phosphorylation of LIN-11, Isl1, and MEC-3 protein domain kinase, as well as cofilin. This phosphorylation is a critical step in cofilin recycling and actin polymerization mediating cytoskeletal rearrangement. Additionally, EGF-induced phosphorylation of Akt and mTOR was suppressed by upregulation of EBP50. Our results indicate that EBP50 is significantly involved in breast cancer invasion/metastasis via LIMK/cofilin and the PI3K/Akt/mTOR/MMP signaling pathway.