Effects of Lactate Transport Inhibition by AZD3965 in Muscle-Invasive Urothelial Bladder Cancer

The Warburg Effect is characterized by high rates of glucose uptake and lactate production. Monocarboxylate transporters (MCTs) are crucial to avoid cellular acidosis by internal lactate accumulation, being largely overexpressed by cancer cells and associated with cancer aggressiveness. The MCT1-specific inhibitor AZD3965 has shown encouraging results in different cancer models. However, it has not been tested in urothelial bladder cancer (UBC), a neoplasm where rates of recurrence, progression and platinum-based resistance are generally elevated. We used two muscle-invasive UBC cell lines to study AZD3965 activity regarding lactate production, UBC cells' viability and proliferation, cell cycle profile, and migration and invasion properties. An "in vivo" assay with the chick chorioallantoic membrane model was additionally performed, as well as the combination of the compound with cisplatin. AZD3965 demonstrated anticancer activity upon low levels of MCT4, while a general lack of sensitivity was observed under MCT4 high expression. Cell viability, proliferation and migration were reduced, cell cycle was arrested, and tumor growth "in vivo" was inhibited. The compound sensitized these MCT4-low-expressing cells to cisplatin. Thus, AZD3965 seems to display anticancer properties in UBC under a low MCT4-expression setting, but additional studies are necessary to confirm AZD3965 activity in this cancer model.

Epigenetically-regulated miR-30a/c-5p directly target TWF1 and hamper ccRCC cell aggressiveness

Clear cell renal cell carcinoma (ccRCC) is highly prone to metastasize and displays an extremely low 5-year survival rate. Not only miRNAs (miRs) are key gene expression regulators but can also be epigenetically modified. Abnormal miR expression has been linked with epithelial-mesenchymal transition (EMT)-driven ccRCC progression. MiR-30a/c-5p were found downregulated in ccRCC and associated with aggressiveness. Herein, we sought to unravel miR-30a/c-5p mechanistic role in ccRCC. RNA sequencing and genome-wide methylome data of ccRCC and normal tissue samples from The Cancer Genome Atlas database were integrated to identify candidate miRs cytosine-phosphate-guanine (CpG) loci deregulated in ccRCC. TargetScan was searched to identify miR putative targets. MiR-30a/c-5p expression and promoter methylation was evaluated in vitro, by PCR. Western blot, functional and luciferase assays were performed after cell transfection with either pre-miR, antimiR, or siRNA against twinfilin-1 (TWF1). Immunohistochemistry (IHC) was performed in ccRCC tissues. We found miR-30c-5p downregulation and aberrant promoter methylation in ccRCC tissues. In vitro studies revealed concomitant miR-30a/c-5p downregulation and increased promoter methylation, as well as a significant re-expression following decitabine treatment. Functional assays demonstrated that both miRs significantly decreased cell aggressiveness and the protein levels of EMT-promoting players, while upregulating epithelial markers, namely Claudin-1 and ZO-1. Importantly, we confirmed TWF1 as a direct target of both miRs, and its potential involvement in epithelial-mesenchymal transition/mesenchymal-epithelial transition regulation. IHC analysis revealed higher TWF1 expression in primary tissues from patients that developed metastases, after surgical treatment. Our results implicate miR-30a/c-5p in ccRCC cells' aggressiveness attenuation by directly targeting TWF1 and hampering EMT.

Chronic Stress Does Not Influence the Survival of Mouse Models of Glioblastoma

The existence of a clear association between stress and cancer is still a matter of debate. Recent studies suggest that chronic stress is associated with some cancer types and may influence tumor initiation and patient prognosis, but its role in brain tumors is not known. Glioblastoma (GBM) is a highly malignant primary brain cancer, for which effective treatments do not exist. Understanding how chronic stress, or its effector hormones glucocorticoids (GCs), may modulate GBM aggressiveness is of great importance. To address this, we used both syngeneic and xenograft in vivo orthotopic mouse models of GBM, in immunocompetent C57BL/6J or immunodeficient NSG mice, respectively, to evaluate how different paradigms of stress exposure could influence GBM aggressiveness and animals’ overall survival (OS). Our results demonstrated that a previous exposure to exogenous corticosterone administration, chronic restraint stress, or chronic unpredictable stress do not impact the OS of these mice models of GBM. Concordantly, ex vivo analyses of various GBM-relevant genes showed similar intra-tumor expression levels across all experimental groups. These findings suggest that corticosterone and chronic stress do not significantly affect GBM aggressiveness in murine models.

Cadherin‐3 is a novel oncogenic biomarker with prognostic value in glioblastoma

Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults. The prognosis of patients is very poor, with a median overall survival of ~ 15 months after diagnosis. Cadherin‐3 (also known as P‐cadherin), a cell–cell adhesion molecule encoded by the CDH3 gene, is deregulated in several cancer types, but its relevance in GBM is unknown. In this study, we investigated the functional roles, the associated molecular signatures, and the prognostic value of CDH3/P‐cadherin in this highly malignant brain tumor. CDH3/P‐cadherin mRNA and protein levels were evaluated in human glioma samples. Knockdown and overexpression models of P‐cadherin in GBM were used to evaluate its functional role in vitro and in vivo. CDH3‐associated gene signatures were identified by enrichment analyses and correlations. The impact of CDH3 in the survival of GBM patients was assessed in independent cohorts using both univariable and multivariable models. We found that P‐cadherin protein is expressed in a subset of gliomas, with an increased percentage of positive samples in grade IV tumors. Concordantly, CDH3 mRNA levels in glioma samples from The Cancer Genome Atlas (TCGA) database are increased in high‐grade gliomas. P‐cadherin displays oncogenic functions in multiple knockdown and overexpression GBM cell models by affecting cell viability, cell cycle, cell invasion, migration, and neurosphere formation capacity. Genes that were positively correlated with CDH3 are enriched for oncogenic pathways commonly activated in GBM. In vivo, GBM cells expressing high levels of P‐cadherin generate larger subcutaneous tumors and cause shorter survival of mice in an orthotopic intracranial model. Concomitantly, high CDH3 expression is predictive of shorter overall survival of GBM patients in independent cohorts. Together, our results show that CDH3/P‐cadherin expression is associated with aggressiveness features of GBM and poor patient prognosis, suggesting that it may be a novel therapeutic target for this deadly brain tumor.

MCT1 Is a New Prognostic Biomarker and Its Therapeutic Inhibition Boosts Response to Temozolomide in Human Glioblastoma

Simple Summary

Glioblastoma, the brain tumour with highest prevalence and lethality, exhibits a characteristic glycolytic phenotype with increased lactate production. Recently, we reported a MCT1 overexpression in GBMs tumours, being associated to tumour growth and aggressiveness. Thus, we aimed to disclose the role of MCT1 in GBM prognosis and in vivo therapy response. Importantly, MCT1 overexpression is associated with poor prognosis of GBM. Moreover, MCT1 inhibition retards GBM tumour growth and boosts response to temozolomide treatment.

Abstract

Background: Glioblastomas (GBMs) present remarkable metabolism reprograming, in which many cells display the “Warburg effect”, with the production of high levels of lactate that are extruded to the tumour microenvironment by monocarboxylate transporters (MCTs). We described previously that MCT1 is up-regulated in human GBM samples, and MCT1 inhibition decreases glioma cell viability and aggressiveness. In the present study, we aimed to unveil the role of MCT1 in GBM prognosis and to explore it as a target for GBM therapy in vivo. Methods: MCT1 activity and protein expression were inhibited by AR-C155858 and CHC compounds or stable knockdown with shRNA, respectively, to assess in vitro and in vivo the effects of MCT1 inhibition and on response of GBM to temozolomide. Survival analyses on GBM patient cohorts were performed using Cox regression and Log-rank tests. Results: High levels of MCT1 expression were revealed to be a predictor of poor prognosis in multiple cohorts of GBM patients. Functionally, in U251 GBM cells, MCT1 stable knockdown decreased glucose consumption and lactate efflux, compromising the response to the MCT1 inhibitors CHC and AR-C155858. MCT1 knockdown significantly increased the survival of orthotopic GBM intracranial mice models when compared to their control counterparts. Furthermore, MCT1 downregulation increased the sensitivity to temozolomide in vitro and in vivo, resulting in significantly longer mice survival. Conclusions: This work provides first evidence for MCT1 as a new prognostic biomarker of GBM survival and further supports MCT1 targeting, alone or in combination with classical chemotherapy, for the treatment of GBM.

Fucoidan/chitosan nanoparticles functionalized with anti-ErbB-2 target breast cancer cells and impair tumor growth in vivo

The work herein presented reports the development of fucoidan/chitosan nanoparticles (NPs) loaded with gemcitabine and functionalized with ErbB-2 antibody at their surface (NPs + Gem + Ab). The maximum immobilization of ErbB-2 on NPs' surface was set at 10 μg mL^-1 and resulted in NPs with a size around 160 nm, a polydispersity index of 0.18, and a zeta potential of 21 mV. ErbB-2 is overexpressed in some subtypes of breast cancers, and the targeting capability of the NPs + Gem + Ab system was confirmed by an increased cellular uptake of SKBR3 cells (ErbB-2 positive) when compared to MDA-MB-231 (ErbB-2 negative). To validate the targeting efficacy of NPs + Gem + Ab, a co-culture system with human endothelial and SKBR3 cells was established. Cytotoxic effects over endothelial cells were similar for all the tested conditions (between 25 and 30%). However, the NPs + Gem + Ab system presented increased toxicity over breast cancer cells, above 80% after 24 h, when compared to free Gem and NPs + Gem (around 15% and 20%, respectively). In vivo studies demonstrated that the developed targeting system significantly reduced tumor growth and the appearance of lung metastasis compared to untreated controls. In summary, the efficacy of the NPs + Gem + Ab system to target cancer cells was established and validated both in vitro and in vivo, being a compelling alternative strategy to current chemotherapeutic approaches.

Intracellular Autofluorescence as a New Biomarker for Cancer Stem Cells in Glioblastoma

The identification of cancer stem cells (CSCs), which are implicated in tumor initiation, progression, therapy resistance, and relapse, is of great biological and clinical relevance. In glioblastoma (GBM), this is still a challenge, as no single marker is able to universally identify populations of GBM cancer stem cells (GSCs). Indeed, there is still controversy on whether biomarker-expressing cells fulfill the functional criteria of bona fide GSCs, despite being widely used. Here, we describe a novel subpopulation of autofluorescent (Fluo+) cells in GBM that bear all the functional characteristics of GSCs, including higher capacity to grow as neurospheres, long-term self-renewal ability, increased expression of stem cell markers, and enhanced in vivo tumorigenicity. Mechanistically, the autofluorescent phenotype is largely due to the intracellular accumulation of riboflavin, mediated by the ABC transporter ABCG2. In summary, our work identifies an intrinsic cellular autofluorescent phenotype enriched in GBM cells with functional stem cells features that can be used as a novel, simple and reliable biomarker to target these highly malignant tumors, with implications for GBM biological and clinical research.

Exploiting the Complexities of Glioblastoma Stem Cells: Insights for Cancer Initiation and Therapeutic Targeting

The discovery of glioblastoma stem cells (GSCs) in the 2000s revolutionized the cancer research field, raising new questions regarding the putative cell(s) of origin of this tumor type, and partly explaining the highly heterogeneous nature of glioblastoma (GBM). Increasing evidence has suggested that GSCs play critical roles in tumor initiation, progression, and resistance to conventional therapies. The remarkable oncogenic features of GSCs have generated significant interest in better defining and characterizing these cells and determining novel pathways driving GBM that could constitute attractive key therapeutic targets. While exciting breakthroughs have been achieved in the field, the characterization of GSCs is a challenge and the cell of origin of GBM remains controversial. For example, the use of several cell-surface molecular markers to identify and isolate GSCs has been a challenge. It is now widely accepted that none of these markers is, per se, sufficiently robust to distinguish GSCs from normal stem cells. Finding new strategies that are able to more efficiently and specifically target these niches could also prove invaluable against this devastating and therapy-insensitive tumor. In this review paper, we summarize the most relevant findings and discuss emerging concepts and open questions in the field of GSCs, some of which are, to some extent, pertinent to other cancer stem cells.

MicroRNA-30a-5pme: a novel diagnostic and prognostic biomarker for clear cell renal cell carcinoma in tissue and urine samples

Background

The rising incidence of renal cell carcinomas (RCC) constitutes a significant challenge owing to risk of overtreatment. Because aberrant microRNA (miR) promoter methylation contributes to cancer development, we investigated whether altered miR-30a-5p expression associates with DNA promoter methylation and evaluated the usefulness as clear cell RCC (ccRCC) diagnostic and prognostic markers.

Methods

Genome-wide methylome and RNA sequencing data from a set of ccRCC and normal tissue samples from The Cancer Genome Atlas (TCGA) database were integrated to identify candidate CpG loci involved in cancer onset. MiR-30a-5p expression and promoter methylation were quantitatively assessed by PCR in a tissue set (Cohort #1) and urine sets (Cohorts #2 and 3) from IPOPorto and Homburg University Hospital. Non-parametric tests were used for comparing continuous variables. MiR-30a-5p promoter methylation (miR-30a-5p^me) performance as diagnostic (receiver operator characteristics [ROC] - validity estimates) and prognostic [metastasis-free (MFS) and disease-specific survival (DSS)] biomarker was further validated in urine samples from ccRCC patients by Kaplan Meier curves (with log rank) and both univariable and multivariable analysis.

Results

Two significant hypermethylated CpG loci in TCGA ccRCC samples, correlating with miR-30a-5p transcriptional downregulation, were disclosed. MiR-30a-5p^me in ccRCC tissues was confirmed in an independent patient’s cohort of IPOPorto and associated with shorter time to relapse. In urine samples, miR-30a-5p^me levels identified cancer both in testing and validation cohorts, with 83% sensitivity/53% specificity and 63% sensitivity/67% specificity, respectively. Moreover, higher miR-30a-5p^me levels independently predicted metastatic dissemination and survival.

Conclusion

To the best of our knowledge, this is the first study validating the diagnostic and prognostic potential of miR-30a-5p^me for ccRCC in urine samples, providing new insights for its clinical usefulness as non-invasive cancer biomarker.

A novel molecular link between HOXA9 and WNT6 in glioblastoma identifies a subgroup of patients with particular poor prognosis

Despite much effort to improve treatments, patients with malignant glioma still present a very poor prognosis that has not changed significantly in the last decades. In this context, it is crucial to better understand glioma pathogenesis to identify new molecular prognostic subgroups and therapeutic targets. WNT6 was recently identified as a new oncogenic molecule in glioblastoma (GBM), with prognostic value in patients, but the mechanisms underlying WNT6 aberrant expression in glioma are still unknown. WNT6 was overexpressed in a subset of gliomas independently of IDH mutations, 1p/19q codeletion status, and WNT6 gene copy number. Interestingly, WNT6 expression is associated with the DNA methylation levels of particular CpG regions at both the WNT6 promoter and the gene body in glioma patient samples. HOXA9, a transcription factor previously associated with poorer clinical outcome in GBM, was identified as a novel transcriptional regulator of WNT6, activating the WNT/β‐catenin pathway in vitro and in vivo. In various cohorts of glioma patients, mRNA levels of WNT6 and HOXA9 were significantly correlated, extending our in vitro and in vivo findings into the clinical setting. Interestingly, this novel molecular link between WNT6 and HOXA9 was not limited to glioma, as they were co‐expressed also in patients with other tumor types. Clinically, WNT6 was a prognostic biomarker of shorter survival in GBM, independently of HOXA9 expression. Concomitant high expression of both WNT6 and HOXA9 identified a subgroup of patients with particularly dismal survival. These findings describe novel WNT6 regulatory mechanisms in GBM, establishing particular DNA methylation patterns and HOXA9 as critical regulators of WNT6 expression in glioma. This HOXA9‐WNT6 molecular link supports WNT signaling in GBM cells and is a powerful prognostic biomarker, highlighting the clinical relevance of this axis in patients. Novel therapies targeting WNT6‐HOXA9 signaling may thus be useful for this deadly disease.

HOX gene cluster (de)regulation in brain: from neurodevelopment to malignant glial tumours

HOX genes encode a family of evolutionarily conserved homeodomain transcription factors that are crucial both during development and adult life. In humans, 39 HOX genes are arranged in four clusters (HOXA, B, C, and D) in chromosomes 7, 17, 12, and 2, respectively. During embryonic development, particular epigenetic states accompany their expression along the anterior-posterior body axis. This tightly regulated temporal-spatial expression pattern reflects their relative chromosomal localization, and is critical for normal embryonic brain development when HOX genes are mainly expressed in the hindbrain and mostly absent in the forebrain region. Epigenetic marks, mostly polycomb-associated, are dynamically regulated at HOX loci and regulatory regions to ensure the finely tuned HOX activation and repression, highlighting a crucial epigenetic plasticity necessary for homeostatic development. HOX genes are essentially absent in healthy adult brain, whereas they are detected in malignant brain tumours, namely gliomas, where HOX genes display critical roles by regulating several hallmarks of cancer. Here, we review the major mechanisms involved in HOX genes (de)regulation in the brain, from embryonic to adult stages, in physiological and oncologic conditions. We focus particularly on the emerging causes of HOX gene deregulation in glioma, as well as on their functional and clinical implications.

Overexpression of circulating MiR-30b-5p identifies advanced breast cancer

BACKGROUND

Breast cancer (BrC) remains the leading cause of cancer-related death in women, mainly due to recurrent and/or metastatic events, entailing the need for biomarkers predictive of progression to advanced disease. MicroRNAs hold promise as noninvasive cancer biomarkers due to their inherent stability and resilience in tissues and bodily fluids. There is increasing evidence that specific microRNAs play a functional role at different steps of the metastatic cascade, behaving as signaling mediators to enable the colonization of a specific organ. Herein, we aimed to evaluate the biomarker performance of microRNAs previously reported as associated with prognosis for predicting BrC progression in liquid biopsies.

METHODS

Selected microRNAs were assessed using a quantitative reverse transcription-polymerase chain reaction in a testing cohort of formalin-fixed paraffin-embedded primary (n = 16) and metastatic BrC tissues (n = 22). Then, miR-30b-5p and miR-200b-3p were assessed in a validation cohort #1 of formalin-fixed paraffin-embedded primary (n = 82) and metastatic BrC tissues (n = 93), whereas only miR-30b-5p was validated on a validation cohort #2 of liquid biopsies from BrC patients with localized (n = 20) and advanced (n = 25) disease. ROC curve was constructed to evaluate prognostic performance.

RESULTS

MiR-30b-5p was differentially expressed in primary tumors and paired metastatic lesions, with bone metastases displaying significantly higher miR-30b-5p expression levels, paralleling the corresponding primary tumors. Interestingly, patients with advanced disease disclosed increased circulating miR-30b-5p expression compared to patients with localized BrC.

CONCLUSIONS

MiR-30b-5p might identify BrC patients at higher risk of disease progression, thus, providing a useful clinical tool for patients' monitoring, entailing earlier and more effective treatment. Nonetheless, validation in larger multicentric cohorts is mandatory to confirm these findings.

WNT6 is a novel oncogenic prognostic biomarker in human glioblastoma

Glioblastoma (GBM) is a universally fatal brain cancer, for which novel therapies targeting specific underlying oncogenic events are urgently needed. While the WNT pathway has been shown to be frequently activated in GBM, constituting a potential therapeutic target, the relevance of WNT6, an activator of this pathway, remains unknown.

Methods: WNT6 protein and mRNA levels were evaluated in GBM. WNT6 levels were silenced or overexpressed in GBM cells to assess functional effects in vitro and in vivo. Phospho-kinase arrays and TCF/LEF reporter assays were used to identify WNT6-signaling pathways, and significant associations with stem cell features and cancer-related pathways were validated in patients. Survival analyses were performed with Cox regression and Log-rank tests. Meta-analyses were used to calculate the estimated pooled effect.

Results: We show that WNT6 is significantly overexpressed in GBMs, as compared to lower-grade gliomas and normal brain, at mRNA and protein levels. Functionally, WNT6 increases typical oncogenic activities in GBM cells, including viability, proliferation, glioma stem cell capacity, invasion, migration, and resistance to temozolomide chemotherapy. Concordantly, in in vivo orthotopic GBM mice models, using both overexpressing and silencing models, WNT6 expression was associated with shorter overall survival, and increased features of tumor aggressiveness. Mechanistically, WNT6 contributes to activate typical oncogenic pathways, including Src and STAT, which intertwined with the WNT pathway may be critical effectors of WNT6-associated aggressiveness in GBM. Clinically, we establish WNT6 as an independent prognostic biomarker of shorter survival in GBM patients from several independent cohorts.

Conclusion: Our findings establish WNT6 as a novel oncogene in GBM, opening opportunities to develop more rational therapies to treat this highly aggressive tumor.

SETDB2 and RIOX2 are differentially expressed among renal cell tumor subtypes, associating with prognosis and metastization

Increasing detection of small renal masses by imaging techniques entails the need for accurate discrimination between benign and malignant renal cell tumors (RCTs) as well as among malignant RCTs, owing to differential risk of progression through metastization. Although histone methylation has been implicated in renal tumorigenesis, its potential as biomarker for renal cell carcinoma (RCC) progression remains largely unexplored. Thus, we aimed to characterize the differential expression of histone methyltransferases (HMTs) and histone demethylases (HDMs) in RCTs to assess their potential as metastasis biomarkers. We found that SETDB2 and RIOX2 (encoding for an HMT and an HDM, respectively) expression levels was significantly altered in RCTs; these genes were further selected for validation by quantitative RT-PCR in 160 RCTs. Moreover, SETDB2, RIOX2, and three genes encoding for enzymes involved in histone methylation (NO66, SETD3, and SMYD2), previously reported by our group, were quantified (RT-PCR) in an independent series of 62 clear cell renal cell carcinoma (ccRCC) to assess its potential role in ccRCC metastasis development. Additional validation was performed using TCGA dataset. SETDB2 and RIOX2 transcripts were overexpressed in RCTs compared to renal normal tissues (RNTs) and in oncocytomas vs. RCCs, with ccRCC and papillary renal cell carcinoma (pRCC) displaying the lowest levels. Low SETDB2 expression levels and higher stage independently predicted shorter disease-free survival. In our 62 ccRCC cohort, significantly higher RIOX2, but not SETDB2, expression levels were depicted in cases that developed metastasis during follow-up. These findings were not apparent in TCGA dataset. We concluded that SETDB2 and RIOX2 might be involved in renal tumorigenesis and RCC progression, especially in metastatic spread. Moreover, SETDB2 expression levels might independently discriminate among RCC subgroups with distinct outcome, whereas higher RIOX2 transcript levels might identify ccRCC cases with more propensity to endure metastatic dissemination.

Transcriptional profiling of HOXA9-regulated genes in human glioblastoma cell models

The data here described pertain to the article by Pojo et al. (2015) [10] titled “A transcriptomic signature mediated by HOXA9 promotes human glioblastoma initiation, aggressiveness and resistance to temozolomide” (Pojoet al., 2015 [10]). HOX genes are part of the homeobox gene family, which encodes transcription factors crucial during embryonic development (Grier et al., 2005; Pearson et al., 2005 [6,9]) and also in post developmental regulation(Neville et al., 2002; Yamamoto et al., 2003; Takahashi et al., 2004;Morgan 2006 [8,14,13,7]). Alterations interfering with the regulation of these genes may lead to tumorigenesis in adults. Due to their contributions in the control of important cellular processes, the deregulation of HOX genes is ultimately correlated with cancer treatment failure and patients' poor prognosis (Golub et al., 1999; Abdel-Fattah et al., 2006 [5,1]; Costa et al.,2010 [4]; Pojo et al., 2015 [10]). Recently, our studies showed that HOXA9 overexpression is associated with poor prognosis in patients with glioblastoma (GBM), the most common and most malignant primary brain tumor. Mechanistically, HOXA9 is associated with resistance to chemotherapy and with pro-proliferative, pro invasive and anti-apoptotic features (Costa et al., 2010 [4]; Pojo et al., 2015 [10]) in GBM in vitro models. Since HOXA9 is a transcription factor, its target genes can be the true biological effectors of its aggressiveness. In this context, whole genome Agilent's microarrays were used to obtain the full transcriptome of HOXA9 in a variety of GBM cell models, including human immortalized astrocytes, established GBM cell lines, and GBM patient derived cell cultures. Here, we provide detailed methods, including experimental design and microarray data analyses,which can be accessed in Gene Expression Omnibus (GEO) under the accession number GSE56517. Additional interpretation of the data is included and supplemented in (Pojo et al., 2015 [10]).

MicroRNA-375 plays a dual role in prostate carcinogenesis

Background

Prostate cancer (PCa), a highly incident and heterogeneous malignancy, mostly affects men from developed countries. Increased knowledge of the biological mechanisms underlying PCa onset and progression are critical for improved clinical management. MicroRNAs (miRNAs) deregulation is common in human cancers, and understanding how it impacts in PCa is of major importance. MiRNAs are mostly downregulated in cancer, although some are overexpressed, playing a critical role in tumor initiation and progression. We aimed to identify miRNAs overexpressed in PCa and subsequently determine its impact in tumorigenesis.

Results

MicroRNA expression profiling in primary PCa and morphological normal prostate (MNPT) tissues identified 17 miRNAs significantly overexpressed in PCa. Expression of three miRNAs, not previously associated with PCa, was subsequently assessed in large independent sets of primary tumors, in which miR-182 and miR-375 were validated, but not miR-32. Significantly higher expression levels of miR-375 were depicted in patients with higher Gleason score and more advanced pathological stage, as well as with regional lymph nodes metastases. Forced expression of miR-375 in PC-3 cells, which display the lowest miR-375 levels among PCa cell lines, increased apoptosis and reduced invasion ability and cell viability. Intriguingly, in 22Rv1 cells, which displayed the highest miR-375 expression, knockdown experiments also attenuated the malignant phenotype. Gene ontology analysis implicated miR-375 in several key pathways deregulated in PCa, including cell cycle and cell differentiation. Moreover, CCND2 was identified as putative miR-375 target in PCa, confirmed by luciferase assay.

Conclusions

A dual role for miR-375 in prostate cancer progression is suggested, highlighting the importance of cellular context on microRNA targeting.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0076-2) contains supplementary material, which is available to authorized users.

A transcriptomic signature mediated by HOXA9 promotes human glioblastoma initiation, aggressiveness and resistance to temozolomide

Glioblastoma is the most malignant brain tumor, exhibiting remarkable resistance to treatment. Here we investigated the oncogenic potential of HOXA9 in gliomagenesis, the molecular and cellular mechanisms by which HOXA9 renders glioblastoma more aggressive, and how HOXA9 affects response to chemotherapy and survival. The prognostic value of HOXA9 in glioblastoma patients was validated in two large datasets from TCGA and Rembrandt, where high HOXA9 levels were associated with shorter survival. Transcriptomic analyses identified novel HOXA9-target genes with key roles in cancer-related processes, including cell proliferation, DNA repair, and stem cell maintenance. Functional studies with HOXA9-overexpressing and HOXA9-silenced glioblastoma cell models revealed that HOXA9 promotes cell viability, stemness and invasion, and inhibits apoptosis. Additionally, HOXA9 promoted the malignant transformation of human immortalized astrocytes in an orthotopic in vivo model, and caused tumor-associated death. HOXA9 also mediated resistance to temozolomide treatment in vitro and in vivo via upregulation of BCL2. Importantly, the pharmacological inhibition of BCL2 with the BH3 mimetic ABT-737 reverted temozolomide resistance in HOXA9-positive cells. These data establish HOXA9 as a driver of glioma initiation, aggressiveness and resistance to therapy. In the future, the combination of BH3 mimetics with temozolomide should be further explored as an alternative treatment for glioblastoma.

Expression of histone methyltransferases as novel biomarkers for renal cell tumor diagnosis and prognostication

Renal cell tumors (RCTs) are the most lethal of the common urological cancers. The widespread use of imaging entailed an increased detection of small renal masses, emphasizing the need for accurate distinction between benign and malignant RCTs, which is critical for adequate therapeutic management. Histone methylation has been implicated in renal tumorigenesis, but its potential clinical value as RCT biomarker remains mostly unexplored. Hence, the main goal of this study was to identify differentially expressed histone methyltransferases (HMTs) and histone demethylases (HDMs) that might prove useful for RCT diagnosis and prognostication, emphasizing the discrimination between oncocytoma (a benign tumor) and renal cell carcinoma (RCC), especially the chromophobe subtype (chRCC). We found that the expression levels of 3 genes--SMYD2, SETD3, and NO66--was significantly altered in a set of RCTs, which was further validated in a large independent cohort. Higher expression levels were found in RCTs compared to normal renal tissues (RNTs) and in chRCCs comparatively to oncocytomas. SMYD2 and SETD3 mRNA levels correlated with protein expression assessed by immunohistochemistry. SMYD2 transcript levels discriminated RCTs from RNT, with 82.1% sensitivity and 100% specificity [area under curve (AUC) = 0.959], and distinguished chRCCs from oncocytomas, with 71.0% sensitivity and 73.3% specificity (AUC = 0.784). Low expression levels of SMYD2, SETD3, and NO66 were significantly associated with shorter disease-specific and disease-free survival, especially in patients with non-organ confined tumors. We conclude that expression of selected HMTs and HDMs might constitute novel biomarkers to assist in RCT diagnosis and assessment of tumor aggressiveness.

Selection of high heterozygosity popcorn varieties in Brazil based on SSR markers

We analyzed genetic structure and diversity among eight populations of popcorn, using SSR loci as genetic markers. Our objectives were to select SSR loci that could be used to estimate genetic diversity within popcorn populations, and to analyze the genetic structure of promising populations with high levels of heterozygosity that could be used in breeding programs. Fifty-seven alleles (3.7 alleles per locus) were detected; the highest effective number of alleles (4.21) and the highest gene diversity (0.763) were found for the Umc2226 locus. A very high level of population differentiation was found (F(ST) = 0.3664), with F(ST) for each locus ranging from 0.1029 (Umc1664) to 0.6010 (Umc2350). This analysis allowed us to identify SSR loci with high levels of heterozygosity and heterozygous varieties, which could be selected for production of inbred lines and for developing new cultivars.

Towards testing the "honeycomb rippling model" in cerrado

Savannas are tropical formations in which trees and grasses coexist. According to the "honeycomb rippling model", inter-tree competition leads to an effect of trees growing and dying due to competition, which, at fine spatial scale, would resemble honeycomb rippling. The model predicts that the taller the trees, the higher the inter-tree distances and the evenness of inter-tree distances. The model had been corroborated in arid savannas, in what appears to be caused by uneven distribution of rains, but had not yet been tested in seasonal savannas, such as the cerrado, which could be caused by the irregular occurrence of fire.A basic assumption of the model is that strong inter-tree competition affects growth (estimated by height) and mortality (estimated by inter-tree distances). As a first step towards testing this model in the cerrado, we tested this assumption in a single cerrado patch in southeastern Brazil. We placed 80 quadrats, each one with 25 m², in which we sampled all shrubs and trees. For each individual, we measured its height and the distance to its nearest neighbour--the inter-tree distance. We did not find correlations between tree height and both inter-tree distances and evenness of inter-tree distances, refuting the honeycomb rippling model. Inter-tree distances were spatially autocorrelated, but height was not. According to our results, the basic assumption of the model does not apply to seasonal savannas. If, in arid savannas, rainfall events are rare and unpredictable, in seasonal savannas, the rainy season is well-defined and rainfall is considerable. We found horizontal structuring in the community, which may be due to soil nutrient heterogeneity. The absence of vertical structuring suggests that competition for light among adult trees is not as important as competition for nutrients in the soil. We tested the basic assumption of the model in a single patch and at a single moment. To test the model effectively, we suggest this assumption to be tested in many patches over time.

Hepatocellular carcinoma in Brazil: report of a national survey (Florianópolis, SC, 1995)

In order to investigate epidemiological aspects of hepatocellular carcinoma (HCC) in Brazil, basic informations about cases diagnosed from January 1992 to December 1994 were requested to several medical centers of different Brazilian States. A simple questionnaire included age, sex, alcohol abuse (over 80g/day), associated liver cirrhosis, persistent HBV infection (HBsAg), HCV infection (anti-HCV) and serum levels of alpha fetoprotein. 287 cases, over 16 years old, from 19 medical centers of 8 States (Pará, Bahia, Minas Gerais, Espirito Santo, Rio de Janeiro, São Paulo, Paraná and Rio Grande do Sul) were analysed. The results showed: (a) Mean age was 56.3 +/- 14.4 for men and 54.7 +/- 16.8 yr for women and the male/female ratio was 3.4:1. (b) 69.6% were caucasians, 21.8% mullatoes, 4.8% orientals and 3.7% blacks. (c) HBsAg (+) in 77/236 cases (41.6%) without differences between males and females. (d) Anti-HCV (+) in 52/193 cases (26.9%). (e) 7/180 cases were positive both for HBsAg and anti-HCV (3.8%). (f) There was chronic alcoholism in 88/235 cases (37%). (g) HCC was found in cirrhotic livers in 71.2% of 202 cases in which the presence or absence of cirrhosis was reported. (h) Alpha-fetoprotein above 20 ng/ml was found in 124/172 cases (72%) and above 500 ng/ml only in 40 cases (23.2%). These results showed that the HCC in Brazil has an intermediate epidemiological pattern as compared to those from areas of low and high incidence of the tumor. In spite of the high frequency of the association of HCC with the HBV and/or HCV infections, 42% of 180 cases were negative both for HBsAg and anti-HCV, indicating the possible role of other etiological factors. The comparison of data from different States showed some regional differences: higher frequency of associated HBsAg in Pará, Bahia, Minas Gerais and Espírito Santo, higher frequency of associated HCV infection in Rio de Janeiro, São Paulo and States of the Southern region and low frequency of associated liver cirrhosis in Salvador and Rio de Janeiro (55.5 and 50% respectively). Further investigation will be necessary to study the presence of other possible etiological factors as aflatoxins, suggested by the favourable climatic conditions for food contamination by fungi in the majority Brazilian regions.

The effect of ethanol intake on the development of hepatocellular carcinoma in HBsAg carriers

To study the effect of alcohol intake on the latency period for the development of hepatocellular carcinoma in a country where this tumor occurs earlier in life than in Southeast of Asia, Europe or North America, 83 male patients with hepatocellular carcinoma aged over 30 years, in which the HBsAg status and ethanol intake were prospectively investigated, were analyzed with respect to age at the time of diagnosis. Only male patients were used because in Vitória, State of Espírito Santo, the age at the time of diagnosis of hepatocellular carcinoma in females is significantly lower than in males. Only patients aged over 30 years were used because the tumor occurs in young people and children, in which habitual alcohol intake is not common. Forty-six patients with hepatocellular carcinoma HBsAg positive and 36 HBsAg negative were separated in alcohol abusers (daily ingestion above 80 g for a period of 10 years or more) or nonalcoholics. The occurrence of associated liver cirrhosis was determined for each group. For comparison of the average age of the four groups the Student t test and the Kruskall-Wallis test for two groups were used. The results showed that the average age of patients with hepatocellular carcinoma HBsAg positive with habitual alcohol intake was significantly lower than those without drinking habit (44.3 +/- 9.7 and 52.3 +/- 15.7 years; P = 0.011 and 0.028 respectively for Student t test and Kruskall-Wallis test). The average age of patients with hepatocellular carcinoma HBsAg (-) with or without habitual ethanol intake showed no significative differences (56.7 +/- 11.3 and 57.3 +/- 12.4 P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Primary non-Hodgkin's lymphoma of the liver: report of two cases and review of the literature]

Two cases of primary non-Hodgkin lymphoma of the liver are presented, with comments about the main clinical and pathological aspects of the disease based on literature review. Both patients were woman (19 and 62 years old) and presented the same complaints: severe weight loss and presence of fast growing abdominal mass. In both cases the histologic diagnosis showed a non-Hodgkin, diffuse, large cell lymphoma (centroblastic-centrocytic diffuse lymphoma) with intermediate grade of malignancy. One case (19 years) died before treatment. The autopsy showed a large solitary tumor (18 cm in diameter) in the right liver lobe and two small nodules (1 cm) in the subcutaneous tissue of the abdominal wall. The other case (62 years), was treated by partial hepatectomy and chemotherapy. There was a round, solitary tumor (8 cm in diameter) in the left lobe. The patient remains without manifestations of disease relapse 18 months after the treatment. In both cases the tumor did not spread to lymph nodes, spleen and other viscera.

[Hepatocellular carcinoma]

Hepatocellular carcinoma (HCC), one of the most frequent tumors in the world, is included by the World Health Organization as a relevant public health problem in areas of high incidence as Africa and Southeast of Asia. In this review it will be discussed: a) the close relationship between HCC and hepatitis B virus (HBV), the more universal but not the single etiologic factor having other carcinogens and co-carcinogens involved with the origen of the tumor; b) the great variation in geographic distribution of this tumor, including that of Brazil where the incidence of HCC, including the new macroscopic classification according to the pattern of growth and general with liver cirrhosis in all countries where the tumor is diagnosed; d) some morphological aspects of HCC, including the new macroscopic classification according to the pattern of growth and general characteristics of small HCC; e) the clinical and biochemical aspects, calling attention to the evaluation of serum levels of alpha-fetoprotein, not always increased in patients with HCC, and the immage processing methods, specially ultrassonography, as methods for early diagnosis of HCC, being relevant in the follow-up of high risk patients (cirrhotics HBsAg (+]. Finally some comments are done about the therapeutic methods and perspectives of reduction in the incidence of the tumor with the use of vaccination against HBV infection.

Hepatocellular carcinoma HBsAg positive in pregnancy

The authors present a case of hepatocellular carcinoma diagnosed in a pregnant woman (four months pregnancy). The clinical evolution was complicated because of a severe hypoglicemia and the patient died 12 weeks after admission. The fetus died before a tentative of surgical delivery. The patient was HBsAg positive and five out of eight sons (inclusively the fetus), were HBsAg positive. There was not indication that the pregnancy had enhanced the tumor evolution.

[Alcoholic hepatitis: clinical, laboratorial and histological study of 50 cases]

The clinical, laboratorial and histological aspects of 50 cases of alcoholic hepatitis were analysed, as well as the follow-up of 24 patients. The mean age of the 50 patients was 42,9 years (range: 25 to 65 years); 44 were males. The beginning of the symptomatology was insidious in great number of cases. The hepatomegaly was most habitual clinical signal (92% of cases). The jaundice was observed in 58% of the cases. Twenty six per cent of the patients had not manifestation of advanced hepatopaty at the moment of diagnosis. The most constant laboratorial alteration (except the increase of gama-glutamil-transpeptidase, dosed in rare cases) was the increase of SGOT (94%). Histological examination showed necrosis and inflammatory exudate in all cases; steatosis in 98%; Mallory bodies in 78%; fibrosis in 84%; cirrhosis in 44%. In the group of patients that came to the obit at the first internation, jaundice, digestive bleeding, encephalopathy, infection, leucocitosis and decreased prothrombin activity. The follow-up of 24 cases (3 months to 5 years) showed aggravation of illness and frequent evolution to cirrhosis in patient that maintained the alcohol ingestion.

The association of hepatitis B surface antigen (HBs Ag) with hepatocellular carcinoma in Espírito Santo State, Brazil

1. The occurrence of hepatitis B surface antigen (HBs Ag) was investigated in 46 cases of hepatocellular carcinoma (HCC) diagnosed in Vitória, Espírito Santo State, Brazil. 2. Twenty cases were patients in which the HCC was diagnosed by biopsy, laparoscopy or on autopsy from 1977 to 1980. HBs Ag was measured in the serum by reverse passive hemagglutination (13 cases) and radioimmunoassay (7 cases). Twelve cases (60%) were HBs Ag positive. 3. The presence of HBs Ag was studied in 26 cases diagnosed on autopsy using paraffin-embedded liver sections stained with orcein. Eleven cases (42%) showed orcein granules in hepatocytes surrounding the tumor. In only one case were orcein-positive granules detected in the tumor cells. 4. The 50% incidence of HBs Ag among patients with HCC is higher than the occurrence of HBs Ag in the general population of the State of Espírito Santo, i.e. 3.5% among 1300 blood donors to the University Hospital. 5. These data provide additional evidence for the hypothesis that there is a relationship between the hepatitis B virus and the etiology of HCC.