Ubiquitously expressed hematological and neurological expressed 1 downregulates Akt-mediated GSK3β signaling, and its knockdown results in deregulated G2/M transition in prostate cells

hsa_circ_0000092 promotes hepatocellular carcinoma progression through up-regulating HN1 expression by binding to microRNA-338-3p

Circular RNAs (circRNAs) have been identified in diverse cancers for their role in regulating multiple cellular processes by antagonizing microRNAs (miRNAs or miRs). However, the role of circRNA hsa_circ_0000092 in hepatocellular carcinoma (HCC) still remains enigmatic. Therefore, we aimed to investigate the specific mechanism of hsa_circ_0000092 in HCC. Differentially expressed circRNAs associated to HCC were initially analysed. The expression of hsa_circ_0000092, miR-338-3p and HN1 in HCC tissues and cell lines was examined. Next, the interaction among hsa_circ_0000092, miR-338-3p and HN1 was determined by dual-luciferase reporter, RNA pull-down and northern blot assays. Subsequently, a series of mimic, inhibitor or siRNA plasmids were delivered into HCC cells to validate the effects of hsa_circ_0000092, miR-338-3p and HN1 in controlling cell proliferation, migration, invasion and angiogenesis in vitro. Furthermore, the role of hsa_circ_0000092 in tumour growth of HCC in vivo was assessed with hsa_circ_0000092 depleted with siRNA. The hsa_circ_0000092/miR-338-3p/HN1 axis was predicted to participate in the development of HCC. hsa_circ_0000092 and HN1 were highly expressed while miR-338-3p was poorly expressed in HCC tissues and cell lines. hsa_circ_0000092 could competitively bind to miR-338-3p to up-regulate HN1 expression. Moreover, depleted hsa_circ_0000092 or elevated miR-338-3p was shown to suppress HCC cell proliferation, migration, invasion and angiogenesis in vitro via down-regulation of HN1. Furthermore, silencing hsa_circ_0000092 was demonstrated to suppress tumour growth in HCC in vivo. The results of this study suggested that hsa_circ_0000092 impaired miR-338-3p-mediated HN1 inhibition to aggravate the development of HCC, indicating that hsa_circ_0000092 is a potential candidate marker and therapeutic target for HCC.

Hematological and neurological expressed 1 (HN1) activates c-Myc signaling by inhibiting ubiquitin-mediated proteasomal degradation of c-Myc in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a poor prognosis due to the usually advanced stage at diagnosis. Sustained activation of the MYC oncogene is implicated in the development of HCC; however, the molecular mechanisms of MYC deregulation in HCC are poorly understood. Here, real-time PCR and western blotting were used to measure the expression of hematological and neurological expressed 1 (HN1) in HCC cells. Expression of HN1 and MYC in clinical specimens was analyzed using immunohistochemistry. The role of HN1 in HCC proliferation, migration, and invasion was explored in vitro and in vivo. MYC expression was measured using real-time PCR and western blotting. MYC transcriptional activity was assessed using a luciferase reporter system. Expression of MYC target genes was quantified using real-time PCR. Protein interaction between MYC and HN1 was assessed using co-immunoprecipitation and western blotting. We identified HN1 as a novel regulatory factor of the glycogen synthase kinase (GSK) 3β-MYC axis. HN1 expression is elevated in liver tumor tissues and cells, and significantly correlates with poor survival in HCC patients. Upregulation of HN1 promotes, and silencing of HN1 represses, the proliferation and metastasis of liver cancer cells in vitro and in vivo. Moreover, our results demonstrate that HN1 sustains stabilization and persistent activity of MYC via interaction with GSK3β in HCC. Importantly, the tumor-promoting effects of HN1 on HCC cells were attenuated by suppressing MYC. In conclusion, constitutive activation of MYC by HN1 promotes the progression of HCC; therefore, HN1 might be a novel therapeutic target for HCC.

Thirdhand Smoke May Promote Lung Adenocarcinoma Development through HN1

Thirdhand smoke (THS) refers to residual tobacco smoking pollutants that can be adsorbed to indoor surfaces and dust and persist for years after active smoking. THS-related chemicals such as N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are tobacco-specific lung carcinogens that involved in lung cancer development and progression. In this study, we computed the differentially expressed genes (DEGs) between THS and paired control samples. THS-related overexpressed genes (OEs) were overlapped with OEs of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). Survival analyses of these overlapped genes were performed using LUAD and LUSC data. 6 genes were selected for validation based on their expression levels and prognostic value. Hematological and neurological expressed 1 (HN1) was further selected due to its novelty in LUAD research. The potential roles of HN1 in LUAD were explored in several ways. In summary, HN1 is overexpressed in THS samples and is associated with the prognosis of patients with LUAD. It may promote cancer progression through several pathways and could serve as a potential therapeutic target especially for THS-related LUAD. In-depth mechanistic studies and clinical trials are warranted.

HN1 Is Enriched in the S-Phase, Phosphorylated in Mitosis, and Contributes to Cyclin B1 Degradation in Prostate Cancer Cells

HN1 has previously been shown as overexpressed in various cancers. In Prostate cancer, it regulates AR signaling and centrosome-related functions. Previously, in two different studies, HN1 expression has been observed as inversely correlated with Cyclin B1. However, HN1 interacting partners and the role of HN1 interactions in cell cycle pathways have not been completely elucidated. Therefore, we used Prostate cancer cell lines again and utilized both transient and stable inducible overexpression systems to delineate the role of HN1 in the cell cycle. HN1 characterization was performed using treatments of kinase inhibitors, western blotting, flow cytometry, immunofluorescence, cellular fractionation, and immunoprecipitation approaches. Our findings suggest that HN1 overexpression before mitosis (post-G2), using both transient and stable expression systems, leads to S-phase accumulation and causes early mitotic exit after post-G2 overexpression. Mechanistically, HN1 interacted with Cyclin B1 and increased its degradation via ubiquitination through stabilized Cdh1, which is a co-factor of the APC/C complex. Stably HN1-expressing cells exhibited a reduced Cdt1 loading onto chromatin, demonstrating an exit from a G1 to S phenotype. We found HN1 and Cdh1 interaction as a new regulator of the Cyclin B1/CDK1 axis in mitotic regulation which can be explored further to dissect the roles of HN1 in the cell cycle.

HN1L promotes stem cell-like properties by regulating TGF-β signaling pathway through targeting FOXP2 in prostate cancer

Dysregulated hematological and neurological expressed 1-like (HN1L) has been implicated in carcinogenesis of difference cancers, including hepatocellular carcinoma and breast cancer. However, the role of HN1L in the progression of prostate cancer (PCA) remains unknown. Therefore, we aimed to investigate the role of HN1L in stemness and progression of PCA. The expression of HN1L in PCA tissues and cells was determined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), western blot analysis, and/or immunohistochemistry (IHC). CD133+ cells were sorted from PCA cells using magnetic fluorescence cell sorting technology and were considered as cancer stem cells (CSCs). Sphere formation assays, transwell assays, and animal experiments were conducted to assess cell stemness, migration, invasion, and in vivo tumorigenesis, respectively. The results showed that HN1L expression was higher in PCA tissues and cells as compared with normal tissues and cells, as well as in CD133+ cells as compared with CD133- cells. HN1L knockdown significantly decreased the expression levels of CSC markers including OCT4 (POU class 5 homeobox 1), CD44, and SRY-box transcription factor 2, inhibited cell migration, invasion, and tumorigenesis and decreased the number of tumor spheroids and CD133+ cell population. Furthermore, we found that HN1L could bind to forkhead box P2 (FOXP2) and positively regulated transforming growth factor-β (TGF-β) expression via upregulation of FOXP2. In addition, the overexpression of TGF-β in HN1L-knockdown PCA cells increased the number of tumor spheroids and CD133+ cell population, as well as enhanced cell migration and invasion. Collectively, this study demonstrates that HN1L promotes stem cell-like properties and cancer progression by targeting FOXP2 through TGF-β signaling pathway in PCA.

HN1 interacts with γ-tubulin to regulate centrosomes in advanced prostate cancer cells

Prostate cancer is one of the most common cancer for men worldwide with advanced forms showing supernumerary or clustered centrosomes. Hematological and neurological expressed 1 (HN1) also known as Jupiter Microtubule Associated Homolog 1 (JPT1) belongs to a small poorly understood family of genes that are evolutionarily conserved across vertebrate species. The co-expression network of HN1 from the TCGA PRAD dataset indicates the putative role of HN1 in centrosome-related processes in the context of prostate cancer. HN1 expression is low in normal RWPE-1 cells as compared to cancerous androgen-responsive LNCaP and androgen insensitive PC-3 cells. HN1 overexpression resulted in differential response for cell proliferation and cell cycle changes in RWPE-1, LNCaP, and PC-3 cells. Since HN1 overexpression increased the proliferation rate in PC-3 cells, these cells were used for functional characterization of HN1 in advanced prostate carcinogenesis. Furthermore, alterations in HN expression led to an increase in abnormal to normal nuclei ratio and increased chromosomal aberrations in PC-3 cells. We observed the co-localization of HN1 with γ-tubulin foci in prostate cancer cells, further validated by immunoprecipitation. HN1 was observed as physically associated with γ-tubulin and its depletion led to increased γ-tubulin foci and disruption in microtubule spindle assembly. Higher HN1 expression was correlated with prostate cancer as compared to normal tissues. The restoration of HN1 expression after silencing suggested that it has a role in centrosome clustering, implicating a potential role of HN1 in cell division as well as in prostate carcinogenesis warranting further studies.

Skeletal muscle proteomes reveal downregulation of mitochondrial proteins in transition from prediabetes into type 2 diabetes

Skeletal muscle insulin resistance is a central defect in the pathogenesis of type 2 diabetes (T2D). Here, we analyzed skeletal muscle proteome in 148 vastus lateralis muscle biopsies obtained from men covering all glucose tolerance phenotypes: normal, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and T2D. Skeletal muscle proteome was analyzed by a sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics technique. Our data indicate a downregulation in several proteins involved in mitochondrial electron transport or respiratory chain complex assembly already in IFG and IGT muscles, with most profound decreases observed in T2D. Additional phosphoproteomic analysis reveals altered phosphorylation in several signaling pathways in IFG, IGT, and T2D muscles, including those regulating glucose metabolic processes, and the structure of muscle cells. These data reveal several alterations present in skeletal muscle already in prediabetes and highlight impaired mitochondrial energy metabolism in the trajectory from prediabetes into T2D.

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Skeletal muscle proteome from men with all stages of glucose tolerance was analyzed

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Phosphoproteomics reveal altered phosphorylation in IFG, IGT, and T2D muscles

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OXPHOS proteins are decreased in prediabetic muscles, with most decrease in T2D

Angiogenesis-related non-coding RNAs and gastrointestinal cancer

Gastrointestinal (GI) cancers are among the main reasons for cancer death globally. The deadliest types of GI cancer include colon, stomach, and liver cancers. Multiple lines of evidence have shown that angiogenesis has a key role in the growth and metastasis of all GI tumors. Abnormal angiogenesis also has a critical role in many non-malignant diseases. Therefore, angiogenesis is considered to be an important target for improved cancer treatment. Despite much research, the mechanisms governing angiogenesis are not completely understood. Recently, it has been shown that angiogenesis-related non-coding RNAs (ncRNAs) could affect the development of angiogenesis in cancer cells and tumors. The broad family of ncRNAs, which include long non-coding RNAs, microRNAs, and circular RNAs, are related to the development, promotion, and metastasis of GI cancers, especially in angiogenesis. This review discusses the role of ncRNAs in mediating angiogenesis in various types of GI cancers and looks forward to the introduction of mimetics and antagonists as possible therapeutic agents.

HN1L promotes migration and invasion of breast cancer by up-regulating the expression of HMGB1

Recent reports showed that haematological and neurological expressed 1-like (HN1L) gene participated in tumorigenesis and tumour invasion. However, the expression and role of HN1L in breast cancer remain to be investigated. Here, bioinformatics, western blot and immunohistochemistry were used to detect the expression of HN1L in breast cancer. Wound healing, transwell assay, immunofluorescence assay and mass spectrum were used to explore the role and mechanism of HN1L on the migration and invasion of breast cancer, which was confirmed in vivo using a nude mice model. Results showed that HN1L was significantly over-expressed in breast cancer tissues, which was positively correlated with M metastasis of breast cancer patients. Silencing HN1L significantly inhibited the invasion and metastasis of breast cancer cells in vitro and lung metastasis in nude mice metastasis model of breast cancer. Mechanistically, HN1L interacted with HSPA9 and affected the expression of HMGB1, playing a key role in promoting the invasion and metastasis of breast cancer cell. These results suggested that HN1L was an appealing drug target for breast cancer.

HN1 promotes tumor growth and metastasis of anaplastic thyroid carcinoma by interacting with STMN1

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive malignancies frequently associated with extrathyroidal extension and metastasis through pathways that remain unclear. Analysis of the cancer genome atlas (TCGA) database and an independent cohort showed that the expression of hematological and neurological expressed 1 (HN1) was higher in thyroid cancers than in normal tissues, and negatively correlated with progression-free survival. RT-PCR and immunohistochemistry revealed higher HN1 expression in ATC compared to healthy tissues and papillary thyroid carcinoma (PTC). HN1 knockdown attenuated migration and invasion of ATC cells, whereas HN1 overexpression increased migration and invasion of PTC cells. HN1 reduced the acetylation of α-tubulin and promoted progression through epithelial-mesenchymal transition of ATC cells and mouse xenografts. HN1 knockdown significantly attenuated TGF-β-induced mesenchymal phenotype, and inhibited tumor formation and growth of ATC xenografts in nude mice. Loss of STMN1 decreased the malignant potential of HN1, whereas HN1 knockdown in combination with STMN1 overexpression restored the aggressive properties of ATC cells. HN1 increased STMN1 mRNA expression, and prevented STMN1 ubiquitination and subsequent degradation. These results demonstrate that HN1 interacts with STMN1 and drives ATC aggressiveness.

HN1 promotes tumor associated lymphangiogenesis and lymph node metastasis via NF-κB signaling activation in cervical carcinoma

Lymph node metastasis (LNM) is a critical cause for disease progression and treatment failure in cervical cancer. However, the mechanism underlying cervical cancer LNM remains unclear. In this study, HN1 was found to be dramatically upregulated in cervical cancer and patients with higher HN1 expression are more likely to exhibit a higher rate of LNM and lower survival rate. Univariate and multivariate Cox-regression analyses showed that HN1 is an independent prognostic factor in cervical cancer. Meanwhile, HN1 promotes lymphangiogenesis of cervical cancer in vitro. The in vivo experiment also indicates that HN1 enhances LNM in cervical cancer. Furthermore, we also found that HN1 activated the NF-κB signaling pathway to enhance the expression of downstream genes. Taken together, our study suggests that HN1 plays a crucial role in promoting LNM and acts as a prognostic biomarker in cervical cancer.

Jupiter microtubule-associated homolog 1 (JPT1): A predictive and pharmacodynamic biomarker of metformin response in endometrial cancers

Preoperative use of metformin in obese women with endometrioid endometrial cancer (EEC) reduces tumor proliferation and inhibits the mammalian target of rapamycin pathway, though is only effective in select cases. This study sought to identify a predictive and/or pharmacodynamic proteomic signature of metformin response to tailor its pharmacologic use. Matched pre‐ and post‐metformin‐treated tumor tissues from a recently completed preoperative window trial of metformin in EEC patients (ClinicalTrials.gov: NCT01911247) were analyzed by mass spectrometry (MS)‐based proteomic and immunohistochemical analyses. Jupiter microtubule‐associated homolog 1 (JPT1) was significantly elevated in metformin responders (n = 13) vs nonresponders (n = 7), and found to decrease in abundance in metformin responders following treatment; observations that were verified by immunohistochemical staining for JPT1. Metformin response and loss of JPT1 were assessed in RL95‐2 and ACI‐181 endometrial cancer (EC) cell lines. We further identified that silencing of JPT1 abundance does not alter cellular response to metformin or basal cell proliferation, but that JPT1 abundance does decrease in response to metformin treatment in RL95‐2 and ACI‐181 EC cell lines. These data suggest that JPT1 represents a predictive and pharmacodynamic biomarker of metformin response that, if validated in larger patient populations, may enable preoperative EEC patient stratification to metformin treatment and the ability to monitor patient response.

Increased expression of hematological and neurological expressed 1 (HN1) is associated with a poor prognosis of hepatocellular carcinoma and its knockdown inhibits cell growth and migration partly by down-regulation of c-Met

Hematologic and neurological expression 1 (HN1) has been reported to involved in certain cancers, but its role in hepatocellular carcinoma (HCC) is largely unknown. The contribution of HN1 to HCC progression was investigated in the present study. We found that HN1 was significantly up-regulated in HCC tissues, compared with normal tissues, by analyzing the Oncomine and Human Protein Atlas database; and found that high expression of HN1 was markedly associated with worse overall survival, relapse-free survival, progression- free survival and disease-specific survival in HCC patients via exploring the Kaplan-Meier plotter database. Functional assays revealed that HN1 knockdown by siRNA induced G1 cell cycle arrest, and inhibited the growth and migration of HCC cells; accordingly, HN1 over-expression promoted HCC cells proliferation and migration. Further studies indicated that HN1 knockdown reduced the expression of cyclin D1 and CDK4, while upregulated the cell cycle inhibitor p21WAF1/Cip1. Moreover, HN1 knockdown decreased c-Met (receptor tyrosine kinase of hepatocyte growth factor) expression, and suppressed ERK activation, which is a common downstream signaling pathway triggered by c-Met; consistently, HN1 over-expression reversed these effects. Meanwhile, down-regulation of c-Met partly eliminated the effect of HN1 over-expression in HCC cells. Thus, the present findings suggested that HN1 promotes the progression of HCC to some extent by up-regulating the expression of c-Met, and may act as a potential biomarker and therapeutic target for the treatment of HCC.

HN1L is essential for cell growth and survival during nucleopolyhedrovirus infection in silkworm, Bombyx mori

Hematological and neurological expressed 1-like (HN1L) protein is an evolutionarily conserved protein that plays an important role in embryonic development. It has been reported that HN1L is involved in the process of cell growth and cancer formation and that cell cycle arrest occurs during suppression of HN1L expression. Previous studies have demonstrated that the expression levels of the Bombyx mori HN1L protein were significantly downregulated in Bombyx mori Nucleopolyhedrovirus (BmNPV) infected silkworm cells. Transient transfections were performed with plasmids for pIEX-1-HN1L expression in Bombyx mori ovarian cells (BmN) in order to explore the effect of the HN1L protein on the growth of silkworm cells and its regulatory role in the process of viral infection. Cellular localization analysis revealed that HN1L was localized in the cytoplasm and that its upregulation could significantly enhance cellular activity. Furthermore, HN1L could promote G1/S phase conversion, thereby contributing to cell proliferation. Upon infection of BmN cells with BmNPV, the induction of apoptosis increased, although HN1L overexpression could inhibit DNA fragmentation, suggesting that the HN1L protein could inhibit cell apoptosis induced by viral invasion. In addition, Western blotting indicated that the HN1L protein inhibited the activation of caspase-9 zymogen and the expression of Bax protein, although it promoted Bcl-2 expression. Flow cytometry analysis further confirmed that overexpression of HN1L significantly inhibited apoptosis induced by BmNPV infection. Consequently, we demonstrated that BmN HN1L is a protein with multiple functions, which enhanced cell activity, regulated the cell cycle and induced an anti-apoptotic response by BmNPV infection.

Systems pharmacology using mass spectrometry identifies critical response nodes in prostate cancer

In the United States alone one in five newly diagnosed cancers in men are prostate carcinomas (PCa). Androgen receptor (AR) status and the PI3K-AKT-mTOR signal transduction pathway are critical in PCa. After initial response to single drugs targeting these pathways resistance often emerges, indicating the need for combination therapy. Here, we address the question of efficacy of drug combinations and development of resistance mechanisms to targeted therapy by a systems pharmacology approach. We combine targeted perturbation with detailed observation of the molecular response by mass spectrometry. We hypothesize that the molecular short-term (24 h) response reveals details of how PCa cells adapt to counter the anti-proliferative drug effect. With focus on six drugs currently used in PCa treatment or targeting the PI3K-AKT-mTOR signal transduction pathway, we perturbed the LNCaP clone FGC cell line by a total of 21 treatment conditions using single and paired drug combinations. The molecular response was analyzed by the mass spectrometric quantification of 52 proteins. Analysis of the data revealed a pattern of strong responders, i.e., proteins that were consistently downregulated or upregulated across many of the perturbation conditions. The downregulated proteins, HN1, PAK1, and SPAG5, are potential early indicators of drug efficacy and point to previously less well-characterized response pathways in PCa cells. Some of the upregulated proteins such as 14-3-3 proteins and KLK2 may be useful early markers of adaptive response and indicate potential resistance pathways targetable as part of combination therapy to overcome drug resistance. The potential of 14-3-3ζ (YWHAZ) as a target is underscored by the independent observation, based on cancer genomics of surgical specimens, that its DNA copy number and transcript levels tend to increase with PCa disease progression. The combination of systematic drug perturbation combined with detailed observation of short-term molecular response using mass spectrometry is a potentially powerful tool to discover response markers and anti-resistance targets.

Metastatic prostate cancer is often treated with pharmacological agents to prevent the tumor from expanding; however, despite advances in drug development patients often die of the disease. An international research team lead by Ruedi Aebersold (ETH Zürich, Switzerland) and Chris Sander (Dana Faber Cancer Institute, Boston, USA) asked how prostate cancer cells adapt to pharmacological treatment on the molecular protein level and find a general response in their prostate cancer model. Next, they asked if similar changes are found in prostate cancer patients. Indeed, the same proteins upregulated in prostate cancer models are also upregulated in prostate cancer patients. Immediately, this has implications for patient treatment stratification and opens new avenues for drug developments in metastatic prostate cancer.

Proteotoxicity in cardiac amyloidosis: amyloidogenic light chains affect the levels of intracellular proteins in human heart cells

AL amyloidosis is characterized by widespread deposition of immunoglobulin light chains (LCs) as amyloid fibrils. Cardiac involvement is frequent and leads to life-threatening cardiomyopathy. Besides the tissue alteration caused by fibrils, clinical and experimental evidence indicates that cardiac damage is also caused by proteotoxicity of prefibrillar amyloidogenic species. As in other amyloidoses, the damage mechanisms at cellular level are complex and largely undefined. We have characterized the molecular changes in primary human cardiac fibroblasts (hCFs) exposed in vitro to soluble amyloidogenic cardiotoxic LCs from AL cardiomyopathy patients. To evaluate proteome alterations caused by a representative cardiotropic LC, we combined gel-based with label-free shotgun analysis and performed bioinformatics and data validation studies. To assess the generalizability of our results we explored the effects of multiple LCs on hCF viability and on levels of a subset of cellular proteins. Our results indicate that exposure of hCFs to cardiotropic LCs translates into proteome remodeling, associated with apoptosis activation and oxidative stress. The proteome alterations affect proteins involved in cytoskeletal organization, protein synthesis and quality control, mitochondrial activity and metabolism, signal transduction and molecular trafficking. These results support and expand the concept that soluble amyloidogenic cardiotropic LCs exert toxic effects on cardiac cells.

Molecular Signatures Associated with Treatment of Triple-Negative MDA-MB231 Breast Cancer Cells with Histone Deacetylase Inhibitors JAHA and SAHA

Jay Amin hydroxamic acid (JAHA; N8-ferrocenylN¹-hydroxy-octanediamide) is a ferrocene-containing analogue of the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA). JAHA's cytotoxic activity on MDA-MB231 triple negative breast cancer (TNBC) cells at 72 h has been previously demonstrated with an IC₅₀ of 8.45 μM. JAHA's lethal effect was found linked to perturbations of cell cycle, mitochondrial activity, signal transduction, and autophagy mechanisms. To glean novel insights on how MDA-MB231 breast cancer cells respond to the cytotoxic effect induced by JAHA, and to compare the biological effect with the related compound SAHA, we have employed a combination of differential display-PCR, proteome analysis, and COMET assay techniques and shown some differences in the molecular signature profiles induced by exposure to either HDACis. In particular, in contrast to the more numerous and diversified changes induced by SAHA, JAHA has shown a more selective impact on expression of molecular signatures involved in antioxidant activity and DNA repair. Besides expanding the biological knowledge of the effect exerted by the modifications in compound structures on cell phenotype, the molecular elements put in evidence in our study may provide promising targets for therapeutic interventions on TNBCs.

Overexpression of HN1L promotes cell malignant proliferation in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a progressive malignant disease, involving the activation of oncogenes and inactivation of tumor suppressors. In this study, we identified and characterized a novel oncogene hematopoietic- and neurologic-expressed sequence 1-like (HN1L) in human NSCLC. Overexpression of HN1L was frequently detected in primary NSCLC compared with their non-tumor counterparts (P < 0.001), which was significantly associated with tumor size (P = 0.022). In addition, Kaplan-Meier analysis showed that upregulation of HN1L correlated with worse overall survival (P = 0.029) and disease-free survival (P = 0.011) for NSCLC patients. Both in vitro and in vivo studies demonstrated that inhibition of HN1L expression with shRNA dramatically inhibited cell growth, adherent and non-adherent colony formation, and tumorigenicity in nude mice. The positive correlation of HN1L expression and Ki67 level in a large NSCLC samples further suggested the key role of HN1L in the regulation of cell growth. Further study showed that knockdown of HN1L resulted in dramatic cell cycle arrest by interfering with MAPK pathway via interacting with RASA4 protein. In conclusion, HN1L plays a crucial role in the progression of NSCLC by contributing to malignant proliferation, with possible use as a new intervention point for therapeutic strategies.

HN1 contributes to migration, invasion, and tumorigenesis of breast cancer by enhancing MYC activity

BACKGROUND

Hematological and neurological expressed 1 (HN1) is upregulated in many tumors, but the role of HN1 in breast cancer progression and its regulatory mechanism have not been well understood.

METHODS

To study the role of HN1 in the initiation and progression of breast cancer, we examined HN1 levels in breast cancer cells and tissues and analyzed the relationship between HN1 levels and patient survival. We used mammosphere formation assay, side population analysis, wound healing assay, transwell assay, soft agar formation assay, and xenografted tumor model to determine the effect of HN1 on the expansion of breast cancer stem cells, and the migration, invasion and tumorigenesis of breast cancer. To determine whether HN1 regulates MYC, we used quantitative real-time PCR and Western blot analysis to assess the expression of MYC and their targeted genes to determine the phenotype caused by knockdown of MYC in breast cancer cell with HN1 overexpression.

RESULTS

In this study, we found that HN1 was upregulated in breast cancer tissues. Patients with high levels of HN1 expression had significantly shorter survival than those with low HN1 expression. In breast cancer cell line, ectopic overexpression of HN1 not only promoted the expansion of breast cancer stem cells, but also promoted cell migration, invasion, and tumorigenesis, while knockdown of HN1 reduced these effects. Furthermore, there was a positive correlation between MYC (also known as c-MYC) level and HN1 level, mechanism analysis suggested HN1 promoted the expression of MYC and its targeted genes like CDK4, CCND1, p21, CAV1, and SFRP1. Downregulation of MYC abrogated the effect of HN1 overexpression in breast cancer cell lines.

CONCLUSION

Taken together, these data reveal that HN1 promotes the progression of breast cancer by upregulating MYC expression, and might be a therapeutic target for breast cancer.

Tracking Effects of SIL1 Increase: Taking a Closer Look Beyond the Consequences of Elevated Expression Level

SIL1 acts as a co-chaperone for the major ER-resident chaperone BiP and thus plays a role in many BiP-dependent cellular functions such as protein-folding control and unfolded protein response. Whereas the increase of BiP upon cellular stress conditions is a well-known phenomenon, elevation of SIL1 under stress conditions was thus far solely studied in yeast, and different studies indicated an adverse effect of SIL1 increase. This is seemingly in contrast with the beneficial effect of SIL1 increase in surviving neurons in neurodegenerative disorders such as amyotrophic lateral sclerosis and Alzheimer's disease. Here, we addressed these controversial findings. Applying cell biological, morphological and biochemical methods, we demonstrated that SIL1 increases in various mammalian cells and neuronal tissues upon cellular stress. Investigation of heterozygous SIL1 mutant cells and tissues supported this finding. Moreover, SIL1 protein was found to be stabilized during ER stress. Increased SIL1 initiates ER stress in a concentration-dependent manner which agrees with the described adverse SIL1 effect. However, our results also suggest that protective levels are achieved by the secretion of excessive SIL1 and GRP170 and that moderately increased SIL1 also ameliorates cellular fitness under stress conditions. Our immunoprecipitation results indicate that SIL1 might act in a BiP-independent manner. Proteomic studies showed that SIL1 elevation alters the expression of proteins including crucial players in neurodegeneration, especially in Alzheimer's disease. This finding agrees with our observation of increased SIL1 immunoreactivity in surviving neurons of Alzheimer's disease autopsy cases and supports the assumption that SIL1 plays a protective role in neurodegenerative disorders.

HN1 negatively influences the β-catenin/E-cadherin interaction, and contributes to migration in prostate cells

Previously, it has been reported that HN1 is involved in cytoplasmic retention and degradation of androgen receptor in an AKT dependent manner. As HN1 is a hormone inducible gene, and has been shown that it is upregulated in various cancers, we studied the importance of HN1 function in β-catenin signaling in prostate cancer cell line, PC-3 and mammary cancer cell line MDA-MB231. Here, we demonstrated that HN1 physically associates with GSK3β/β-catenin destruction complex and abundantly localizes to cytoplasm, especially when the GSK3β is phosphorylated on S9 residue. Further, ectopic HN1 expression results an increase in the β-catenin degradation leading to loss of E-cadherin interaction, concurrently contributing to actin re-organization, colony formation and migration in cancer cell lines. Thus, we report that HN1 is an essential factor for β-catenin turnover and signaling, augments cell growth and migration in prostate cancer cells.

N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 is overexpressed in cancer and promotes a pro-migratory and pro-metastatic phenotype

N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 (NAALADL2) is a member of the glutamate carboxypeptidase II family, best characterized by prostate-specific membrane antigen (PSMA/NAALAD1). Using immunohistochemistry (IHC), we have shown overexpression of NAALADL2 in colon and prostate tumours when compared with benign tissue. In prostate cancer, NAALADL2 expression was associated with stage and Grade, as well as circulating mRNA levels of the NAALADL2 gene. Overexpression of NAALADL2 was shown to predict poor survival following radical prostatectomy. In contrast to PSMA/NAALAD1, NAALADL2 was localized at the basal cell surface where it promotes adhesion to extracellular matrix proteins. Using stable knockdown and overexpression cell lines, we have demonstrated NAALADL2-dependent changes in cell migration, invasion and colony-forming potential. Expression arrays of the knockdown and overexpression cell lines have identified nine genes that co-expressed with NAALADL2, which included membrane proteins and genes known to be androgen regulated, including the prostate cancer biomarkers AGR2 and SPON2. Androgen regulation was confirmed in a number of these genes, although NAALADL2 itself was not found to be androgen regulated. NAALADL2 was also found to regulate levels of Ser133 phosphorylated C-AMP-binding protein (CREB), a master regulator of a number of cellular processes involved in cancer development and progression. In combination, these data suggest that changes in expression of NAALADL2 can impact upon a number of pro-oncogenic pathways and processes, making it a useful biomarker for both diagnosis and prognosis.

TNFα-mediated loss of β-catenin/E-cadherin association and subsequent increase in cell migration is partially restored by NKX3.1 expression in prostate cells

Inflammation-induced carcinogenesis is associated with increased proliferation and migration/invasion of various types of tumor cells. In this study, altered β-catenin signaling upon TNFα exposure, and relation to loss of function of the tumor suppressor NKX3.1 was examined in prostate cancer cells. We used an in vitro prostate inflammation model to demonstrate altered sub-cellular localization of β-catenin following increased phosphorylation of Akt^(S473) and GSK3β^(S9). Consistently, we observed that subsequent increase in β-catenin transactivation enhanced c-myc, cyclin D1 and MMP2 expressions. Consequently, it was also observed that the β-catenin-E-cadherin association at the plasma membrane was disrupted during acute cytokine exposure. Additionally, it was demonstrated that disrupting cell-cell interactions led to increased migration of LNCaP cells in real-time migration assay. Nevertheless, ectopic expression of NKX3.1, which is degraded upon proinflammatory cytokine exposure in inflammation, was found to induce the degradation of β-catenin by inhibiting Akt^(S473) phosphorylation, therefore, partially rescued the disrupted β-catenin-E-cadherin interaction as well as the cell migration in LNCaP cells upon cytokine exposure. As, the disrupted localization of β-catenin at the cell membrane as well as increased Akt^(S308) priming phosphorylation was observed in human prostate tissues with prostatic inflammatory atrophy (PIA), high-grade prostatic intraepithelial neoplasia (H-PIN) and carcinoma lesions correlated with loss of NKX3.1 expression. Thus, the data indicate that the β-catenin signaling; consequently sub-cellular localization is deregulated in inflammation, associates with prostatic atrophy and PIN pathology.

MiR-132 prohibits proliferation, invasion, migration, and metastasis in breast cancer by targeting HN1

Accumulating evidence indicates that miRNAs play critical roles in tumorigenesis and cancer progression. This study aims to investigate the role and the underlying mechanism of miR-132 in breast cancer. Here, we report that miR-132 is significantly down-regulated in breast cancer tissues and cancer cell lines. Additional study identifies HN1 as a novel direct target of miR-132. MiR-132 down-regulates HN1 expression by binding to the 3' UTR of HN1 transcript, thereby, suppressing multiple oncogenic traits such as cancer cell proliferation, invasion, migration and metastasis in vivo and in vitro. Overexpression of HN1 restores miR-132-suppressed malignancy. Importantly, higher HN1 expression is significantly associated with worse overall survival of breast cancer patients. Taken together, our data demonstrate a critical role of miR-132 in prohibiting cell proliferation, invasion, migration and metastasis in breast cancer through direct suppression of HN1, supporting the potential utility of miR-132 as a novel therapeutic strategy against breast cancer.

Differential gene expression profiles of PPP2R5C-siRNA-treated malignant T cells

Recently, alterations in the expression pattern of PPP2R5C associated with malignant transformation have been characterized, and PPP2R5C overexpression was demonstrated in leukemias. To confirm the role of PPP2R5C in proliferation and its molecular mechanism, three PPP2R5C-siRNAs and a scrambled nonsilencing siRNA control were used to treat Molt-4 and Jurkat T cells. After nucleofection, PPP2R5C expression and biological consequences based on a highly efficient and specific PPP2R5C-siRNA were demonstrated by qRT-PCR, CCK-8 assay, Annexin V/PI, and flow cytometry. The global gene expression profile of PPP2R5C-siRNA-treated Jurkat T cells was established. A significant reduction in the PPP2R5C mRNA level was observed at 24 to 72 h in Molt-4 and Jurkat T cells with all of the PPP2R5C-siRNAs. The proliferation rate of Molt-4 and Jurkat T cells transfected with different PPP2R5C-siRNAs was significantly decreased at 72 h compared with the control (p<0.05). However, the transfected cells did not show a significant increase in Annexin V/PI-positive cells (apoptosis). The highly efficient PPP2R5C-siRNA2 was used to treat Jurkat T cells for gene expression profile analysis. In total, 439 genes were upregulated, and 524 genes were downregulated at least twofold in PPP2R5C-siRNA-treated Jurkat T cells. Changes in signaling pathway genes closely related to the TCR, Wnt, calcium, MAPK, and p53 signaling pathways were observed. In conclusion, the suppression of PPP2R5C by RNA interference could effectively inhibit the proliferation of leukemic T cells, the PPP2R5C-siRNA treatment altered gene expression profiles, and the differential expression of the glycogen synthase kinase 3 beta (GSK-3β), ataxia telangiectasia mutated (ATM), and Mdm2 p53 binding protein homolog (MDM2) genes may play an important role in the effects of PPP2R5C knockdown in Jurkat T cells.

Androgen regulated HN1 leads proteosomal degradation of androgen receptor (AR) and negatively influences AR mediated transactivation in prostate cells

We recently reported that hematological and neurological expressed 1 (HN1) is a ubiquitously expressed, EGF-regulated gene. Expression of HN1 in prostate cell lines down-regulates PI3K-dependent Akt activation. Here, we investigate whether HN1 is regulated by androgens through the putative androgen response elements (AREs) found in its promoter. Knockdown of HN1 expression by siRNA silencing leads to an increase in Akt((S473)) phosphorylation, resulting in the translocation of androgen receptor (AR) to the nucleus; these effects can be abrogated by the non-specific Akt inhibitor LY294002 but not by the ERK inhibitor PD98059. Furthermore, HN1 overexpression correlates with an increase in ubiquitination-mediated degradation (a consequence of the decrease in S213/210 phosphorylation of AR), ultimately resulting in the down-regulation of AR-mediated expression of the KLK3, KLK4, NKX3.1 and STAMP2 genes. We also found that HN1 overexpression suppresses colony formation as well as R1881-mediated growth in LNCaP cells, while it has the opposite effect (increasing colony formation but not proliferation) in PC-3 and DU145 cells. Therefore, we suggest that HN1 maintains a balance between the androgen-regulated nuclear translocation of AR and steady-state Akt phosphorylation, predominantly in the absence of androgens. If so, the balance between cell growth and EGF- and AR-signaling must be tightly regulated by HN1. This work has important implications for prostate cancer research, as AR, EGFR and HN1 are known to be highly expressed in prostate adenocarcinomas.