Endophytic actinobacteria of Hymenachne amplexicaulis from the Brazilian Pantanal wetland produce compounds with antibacterial and antitumor activities.

The increase in the number of deaths from infections caused by multidrug-resistant bacteria and cancer diseases highlights the need for new molecules with biological activity. Actinobacteria represent a potential source of new compounds, as these microorganisms have already produced a great diversity of clinically employed antibiotics. Endophytes from unexplored biomes, such as the Pantanal (the largest wetland in the world), can be a source of new molecules. Hymenachne amplexicaulis is among the unexplored native plants of the Pantanal in terms of its endophytic community. This plant is considered a weed in other countries due to its ability to adapt and compete with native plants, and there is evidence to suggest that the endophytic community of H. amplexicaulis plays an important role in this competitiveness. To explore its therapeutic potential, the present study isolated, identified (using partial sequence of the 16S rDNA) and bioprospected H. amplexicaulis endophytic actinobacteria. Ten isolates belonging to the genera Streptomyces, Microbispora, Leifsonia, and Verrucosispora were obtained from root fragments. The susceptibility profile of the isolates to the different classes of antibiotics was evaluated, with 80 % of the isolates showing resistance to the antibiotics Nalidixic Acid, Ampicillin, Chloramphenicol, Oxacillin, and Rifampicin. To assess antibacterial and antitumor activities, methanolic extracts were obtained by fermentation in SG culture medium at 36 °C at 180 rpm for 10 days. The extract produced from the S. albidoflavus CMRP4854 isolate was the only one to show activity against the Gram-negative bacterium Acinetobacter baumanii. Due to the great clinical importance of this pathogen and the difficulty in obtaining active compounds against it, the CMRP4854 isolate should be further investigated for the identification of active compounds and mode of action. We also emphasize the results obtained by the extract of the isolates Streptomyces albidoflavus CMRP4852 and Verrucosispora sp. CMRP4860 that presented antibacterial effect against Methicilin-resistant Staphylococcus aureus (MRSA) (MIC: 1.5 µg/mL and 13 µg/mL, respectively) and Vancomycin-resistant Enterococcus (VRE) (MIC: 40 µg/mL for both extracts). Extracts (200 µg/mL) of these two endophytes also showed selective cytotoxicity action against murine B16-F10 melanoma cells. However, the CMRP4852 extract also affected the density of normal cells. Due to these results, the crude extract of isolate CMRP4860 Verrucosispora sp., which was the only one that presented cytotoxicity and reduced cell density only in tumor cells, was selected for subsequent analysis involving scale-up fermentation of the CMRP4860 resulting in 9 fractions that were tested against both bacteria and tumor cells, with particular fractions showing promise and meriting further investigation. Taken together, the results of this study not only show for the first time that the endophytic community of H. amplexicaulis actinobacteria can produce secondary metabolites that potentially possess important antibacterial and cytotoxic properties, but also reinforce the pressing need to conserve biomes such as the Brazilian Pantanal.

Novel lncRNAs Co-Expression Networks Identifies LINC00504 with Oncogenic Role in Luminal A Breast Cancer Cells.

Long non-coding RNAs (lncRNAs) are functional transcripts with more than 200 nucleotides. These molecules exhibit great regulatory capacity and may act at different levels of gene expression regulation. Despite this regulatory versatility, the biology of these molecules is still poorly understood. Computational approaches are being increasingly used to elucidate biological mechanisms in which these lncRNAs may be involved. Co-expression networks can serve as great allies in elucidating the possible regulatory contexts in which these molecules are involved. Herein, we propose the use of the pipeline deposited in the RTN package to build lncRNAs co-expression networks using TCGA breast cancer (BC) cohort data. Worldwide, BC is the most common cancer in women and has great molecular heterogeneity. We identified an enriched co-expression network for the validation of relevant cell processes in the context of BC, including LINC00504. This lncRNA has increased expression in luminal subtype A samples, and is associated with prognosis in basal-like subtype. Silencing this lncRNA in luminal A cell lines resulted in decreased cell viability and colony formation. These results highlight the relevance of the proposed method for the identification of lncRNAs in specific biological contexts.

Long non-coding RNAs differential expression in breast cancer subtypes: What do we know?

Breast Cancer (BC) is the most commonly diagnosed cancer and is the leading cause of cancer deaths in women. BC is a heterogeneous disease with different clinical and genetic features. According to immunohistochemical markers, BC is subdivided into four main subtypes: luminal A, luminal B, ERBB2 positive and triple negative. Long non-coding RNAs (lncRNAs) are transcripts with more than 200 nucleotides and deregulated lncRNAs are associated with human diseases, including BC. In order to improve BC molecular classification, non-coding RNAs (ncRNAs), including lncRNAs, have been used. In this review, we focus on lncRNAs with differential expression in BC subtypes and how these RNAs may act to contribute to BC heterogeneity. We also emphasize the potential of these lncRNAs as biomarkers.

Long Non-Coding RNAs in Multifactorial Diseases: Another Layer of Complexity.

Multifactorial diseases such as cancer, cardiovascular conditions and neurological, immunological and metabolic disorders are a group of diseases caused by the combination of genetic and environmental factors. High-throughput RNA sequencing (RNA-seq) technologies have revealed that less than 2% of the genome corresponds to protein-coding genes, although most of the human genome is transcribed. The other transcripts include a large variety of non-coding RNAs (ncRNAs), and the continuous generation of RNA-seq data shows that ncRNAs are strongly deregulated and may be important players in pathological processes. A specific class of ncRNAs, the long non-coding RNAs (lncRNAs), has been intensively studied in human diseases. For clinical purposes, lncRNAs may have advantages mainly because of their specificity and differential expression patterns, as well as their ideal qualities for diagnosis and therapeutics. Multifactorial diseases are the major cause of death worldwide and many aspects of their development are not fully understood. Recent data about lncRNAs has improved our knowledge and helped risk assessment and prognosis of these pathologies. This review summarizes the involvement of some lncRNAs in the most common multifactorial diseases, with a focus on those with published functional data.

[Ru(pipe)(dppb)(bipy)]PF6: A novel ruthenium complex that effectively inhibits ERK activation and cyclin D1 expression in A549 cells.

Lung cancer is the most frequent type of cancer worldwide. In Brazil, only 14% of the patients diagnosed with lung cancer survived 5years in the last decades. Although improvements in the therapeutic approach, it is relevant to identify new chemotherapeutic agents. In this framework, ruthenium metal compounds emerge as a promising alternative to platinum-based compounds once they displayed lower cytotoxicity and more selectivity for tumor cells. The present study aimed to evaluate the antitumor potential of innovative ruthenium(II) complex, [Ru(pipe)(dppb)(bipy)]PF6 (PIPE) on A549 cells, which is derived from non-small cell lung cancer. Results demonstrated that PIPE effectively reduced the viability and proliferation rate of A549 cells. When PIPE was used at 9µM there was increase in G0/G1 cell population with concomitant reduction in frequency of cells in S-phase, indicating cell cycle arrest in G1/S transition. Antiproliferative activity of PIPE was associated to its ability of reducing cyclin D1 expression and ERK phosphorylation levels. Cytotoxic activity of PIPE on A549 cells was observed when PIPE was used at 18µM, which was associated to its ability of inducing apoptosis by intrinsic pathway. Taken together, the data demonstrated that PIPE is a promising antitumor agent and further in vivo studies should be performed.

YM155 induces apoptosis in p53-deficient T-acute lymphoblastic leukemia cells independent of survivin inhibition.

T-acute lymphoblastic leukemia (T-ALL) is an aggressive hematological cancer that arises from the malignant transformation of T-cell progenitors. Despite the significant progress in current treatment, challenges remain the lifelong morbidity after current chemotherapy regimens and postrelapse survival. In addition, patients with T-ALL have inferior outcomes compared with those with B-cell precursor; consequently, novel therapeutic approaches are still necessary to improve the outcome in this cohort. YM155 is an imidazolium derivative originally discovered as a suppressant of survivin expression. It has been reported that YM155 has potent antiproliferative activity on a variety of human cancer cell lines; however, its effects in T-ALL cells have been underexplored. The aim of the present study was to examine the effects of YM155 on p53-deficient T-ALL cell lines, JURKAT and CCRF-CEM. Resazurin dye was used to evaluate cell viability. Colony formation was observed in MethoCult methylcellulose medium. Apoptotic cells were detected by flow cytometry (annexin V labeling and TUNEL assay). Cell cycle analysis was carried out by DNA quantification in flow cytometry. DNA damage was assessed using a comet assay and the survivin expression profile was evaluated by real-time PCR and immunoblotting. YM155 treatment decreased cell viability and clonogenicity capacity of T-ALL cells, increased the apoptosis index and DNA damage, and altered the cell cycle dynamic, independent of survivin inhibition. Taken together, the data reinforce that YM155 may be useful as a therapeutic possibility to combat leukemia.

Long Non-Coding RNA TUG1 Expression Is Associated with Different Subtypes in Human Breast Cancer.

Taurine upregulated 1 gene (TUG1) is a long non-coding RNA associated with several types of cancer. Recently, differential expression of TUG1 was found in cancerous breast tissues and associated with breast cancer malignancy features. Although this is evidence of a potential role in breast cancer, TUG1 expression could not be associated with different subtypes, possibly due to the small number of samples analyzed. Breast cancer is a heterogeneous disease and, based on molecular signatures, may be classified into different subtypes with prognostic implications. In the present study, we include analysis of TUG1 expression in 796 invasive breast carcinoma and 105 normal samples of RNA sequencing (RNA-seq) datasets from The Cancer Genome Atlas (TCGA) and describe that TUG1 expression is increased in HER2-enriched and basal-like subtypes compared to luminal A. Additionally, TUG1 expression is associated with survival in HER2-enriched patients. These results reinforce the importance of TUG1 in breast cancer and outline its potential impact on specific subtypes.

Zebularine induces chemosensitization to methotrexate and efficiently decreases AhR gene methylation in childhood acute lymphoblastic leukemia cells.

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in childhood. Despite the advances in treatment, about 20% of patients relapse and/or die, indicating the need for different therapies for this group. Zebularine (ZB) is a potent DNA methyltransferase (DNMT) inhibitor and has been associated with gene demethylation and enhancement of tumor chemosensitivity. This study aimed to evaluate the effects of ZB, alone or combined with chemotherapeutics (methotrexate and vincristine), on childhood ALL cell lines. Cell proliferation, apoptosis, and clonogenic capacity were studied in Jurkat and ReH cell lines. Bisulfite modification, followed by methylation-specific PCR was carried out to evaluate aryl hydrocarbon receptor (AhR) methylation status. Gene expression of DNMT1, DNMT3a, DNMT3b, and AhR was assessed using qRT-PCR. Both cell cultures were sensitive to ZB, showing a dose-dependent and time-dependent response (P<0.05). ZB induced apoptosis and decreased clonogenic capacity in both cell lines. Combination with methotrexate resulted in a strong synergistic effect, whereas combination with vincristine led to an antagonistic response in both cell lines. ZB treatment decreased gene expression of the three DNMTs and induced AhR gene promoter demethylation and its re-expression. These results indicate that ZB may be a promising drug for the adjuvant treatment of ALL, mainly when combined with methotrexate.

Antiproliferative in vitro effects of BI 2536-mediated PLK1 inhibition on cervical adenocarcinoma cells.

Cervical adenocarcinoma is one of the most common gynecological malignancies. Despite the improvements in multimodality treatment, advanced disease is still associated with a significantly poor prognosis making the search for more effective therapeutic agents imperative. BI 2536, an unambiguous inhibitor of Polo-like kinase 1 (PLK1), has shown anticancer activity in a variety of tumor cell types. Herein, we present more evidence of the antiproliferative effects of this drug on HeLa cells. Nanomolar concentrations (10-100 nmol/l) of the drug significantly decreased cell proliferation and clonogenic capacity. Our results also demonstrate that inhibition of PLK1 promoted G2/M arrest and resulted in a dramatic increase in the mitotic index after 24 h of treatment. Apoptosis onset was evinced by the accumulation of a sub-G1 population as well as by a significant increase in caspase-3 activity at longer periods of exposure. Taken together, our results reinforce the prospect of directing against PLK1 as a potential therapeutic target to be evaluated in different preclinical models for cervical carcinoma.

Cytostatic in vitro effects of DTCM-glutarimide on bladder carcinoma cells.

Bladder cancer is a common malignancy worldwide. Despite the increased use of cisplatin-based combination therapy, the outcomes for patients with advanced disease remain poor. Recently, altered activation of the PI3K/ Akt/mTOR pathway has been associated with reduced patient survival and advanced stage of bladder cancer, making its upstream or downstream components attractive targets for therapeutic intervention. In the present study, we showed that treatment with DTCM-glutaramide, a piperidine that targets PDK1, results in reduced proliferation, diminished cell migration and G1 arrest in 5637 and T24 bladder carcinoma cells. Conversely, no apoptosis, necrosis or autophagy were detected after treatment, suggesting that reduced cell numbers in vitro are a result of diminished proliferation rather than cell death. Furthermore previous exposure to 10 µg/ml DTCM- glutarimide sensitized both cell lines to ionizing radiation. Although more studies are needed to corroborate our findings, our results indicate that PDK1 may be useful as a therapeutic target to prevent progression and abnormal tissue dissemination of urothelial carcinomas.

MicroRNA expression and activity in pediatric acute lymphoblastic leukemia (ALL).

Acute lymphoblastic leukemia (ALL) is the most common type of pediatric neoplasia. Highly heterogeneous, ALL includes several genetic subtypes with varying clinical outcome. Although, some features are well established as prognostic predictors, the details of the molecular mechanisms underlying different phenotypes are only beginning to emerge. Recently, microRNAs (miRNAs) have been shown to influence a range of physiological processes and, consequently, alterations in their expression and functions have been associated with the development of many cancers, including leukemia. This article aims to review the current state of knowledge of the role of miRNAs on the biology of childhood ALL, also including relevant findings from the adult leukemia literature.

BI 2536-mediated PLK1 inhibition suppresses HOS and MG-63 osteosarcoma cell line growth and clonogenicity.

Osteosarcoma is the most common primary malignant tumor of bone, which frequently occurs in the second decade of life. Despite the improvements in neoadjuvant chemotherapy, the outcome of patients with chemoresistant or metastatic tumors is still poor. Therefore, there is a need for the development of more efficient therapeutic agents. BI 2536, an innovative selective inhibitor of Polo-like kinase 1, has shown anticancer potential promoting mitotic arrest and apoptosis in a variety of tumor cells, including osteosarcoma. Here, we present more evidence of the antiproliferative effects of BI 2536 on HOS and MG-63 osteosarcoma cell lines. Our results showed that nanomolar concentrations (10, 50, and 100 nmol/l) of the drug significantly decreased cell proliferation and clonogenic capacity, inducing mitotic arrest and aneuploidy. Interestingly, although BI 2536 mediated a moderate increase of apoptosis after 48 h in HOS cells, no increased caspase-3 activity was detected for MG-63 cells. In contrast to previous studies, we show that perturbation of normal mitotic progression by BI 2536 in these osteosarcoma cell lines results in caspase-independent mitotic catastrophe followed by necrosis. Our findings reinforce the likelihood of directing against Polo-like kinase 1 as a therapeutic option in the treatment of osteosarcoma.

MicroRNA-100 acts as a tumor suppressor in human bladder carcinoma 5637 cells.

Bladder carcinoma is one of the most common tumors in the world and despite the therapy currently available most of the patients relapse. Better understanding of the factors involved in disease pathogenesis would provide insights for the development of more effective strategies in treatment. Recently, differential miRNA expression profiles in bladder urothelial carcinomas identified miR-100 down-regulation and miR-708 up-regulation among the most common alterations, although the possible influence of these miRNAs in the control of basic mechanisms in bladder tumors has not been addressed. In this context, the present study aimed to evaluate the in vitro effects of miR-100 forced expression and miR-708 inhibition in the bladder carcinoma cell line 5637. Our results showed that overexpression of miR-100 significantly inhibited growth when compared to controls at both times tested (72 and 96 hours, p<0.01) with a maximum effect at 72 hours reducing proliferation in 29.6 %. Conversely, no effects on cell growth were observed after inhibition of miR-708. MiR-100 also reduced colony formation capacity of 5637 cells by 24.4%. No alterations in cell cycle progression or apoptosis induction were observed. The effects of miR-100 on growth and clonogenicity capacity in 5637 cells evince a possible role of this miRNA in bladder carcinoma pathogenesis. Further studies are necessary to corroborate our findings and examine the potential use of this microRNA in future therapeutic interventions.