Petra Vychytilová

Genes of the microRNA biogenesis pathway are deregulated in Colorectal cancer

B cancer is one of the most common cancers affecting women. Our lab has previously shown that arginine methylation by arginine methyltransferases (PRMTs) is upregulated in breast cancer. We have further identified a novel modular protein, Tudor domain containing protein 3, TDRD3, and shown its role in reading/sensing of arginine methylation. Furthermore, TDRD3 was among the top hits in the genes that are strongly correlated with poor prognosis of estrogen receptor negative breast cancer (Nagahata et al., 2004). Moreover in the CancerGenome Atlas’ Data Portal, TDRD3 was overexpressed in 58/158 of breast cancer patients. This suggests a potent role of this that this novel gene in the implication of breast cancer. TDRD3 was further shown to re-localzie to stress granules (SGs) upon various environmental stresses. SGs have implications in cancer as they been shown to promote tumor cell survival and mediate resistance to cancer therapy. Therefore, we hypothesize that TDRD3 contributes to late hallmarks of breast cancer pathogenesis through regulating SGs. In this project, we elucidate the role of TDRD3 in assembly/disassembly and dynamic of stress granules. Gaining insight into this novel gene in the light of its role in SGs may eventually have implication on elucidating further, the pathology of breast cancer.MicroRNAs (miRNAs) are small non-coding RNAs 18-25 nucleotides long that regulate gene expression on post-transcriptional level. Therefore, their production and maturation have to be strictly regulated. Their biogenesis starts with the transcription, which is followed by several steps that lead to processing of primary transcripts to mature miRNAs. Each step of this pathway is sophistically regulated and any disruption of control mechanisms may leads to the cancer occurrence. The aim of this study was to analyse the expression of the crucial genes involved in the biogenesis of miRNAs in colorectal cancer (CRC). Expression of 19 selected genes (EIF2C1-4, GEMIN4, DDX20, TARBP2, DICER1, XPO5, DROSHA, DGCR8, POLR2A, DDX5, DDX17, ADAR, ADARB1, TNRC6A, LIN28A/B) has been analysed in tumour tissues of 120 clinically characterized patients with CRC and in 120 parallel healthy tissues by qRT-PCR. Using Wilcoxon test, genes with different expression between tumour tissue and healthy tissue have been identified. Subsequently, Kruskal-Wallis test has been used to find any correlation with the clinical-pathological features of the patients. We have found significantly higher expression of POLRIIA, ADAR, ADARB1, DGCR8, DDX5, DDX17, DROSHA, XPO5, EIF2C1-C4, TARBP2, TNRC6A, GEMIN3, DDX20 and DICER1 (P < 0.0001) and significantly lower expression of LIN28A in tumour tissue of CRC patients. Moreover, negative correlation between the expression of AGO3 and clinical stage of patients (P = 0.0017) and grade (P = 0.0151) and positive correlation between the expression of DICER1 (P = 0.0230) and DROSHA (P = 0.0212) and grade of patients has been observed. Our results show that changes in the expression of genes associated with biogenesis of miRNAs may be associated not only with the origin, but also to progression of CRC and therefore, these molecules could serve as potential new biomarkers or therapeutic targets.Background: Bromelain is the extract of pineapple stem primarily comprised of sulfhydryl containing proteolytic enzymes. N-acetylcysteine (NAC) is also a sulfhydryl-containing compound found in allium plants, asparagus, and red pepper. Biological effects of bromelain and NAC have been studied in some pathologic conditions including cancer. In the present study, we investigated the cytotoxic effects of bromelain and/or NAC on the gastric carcinoma cell line KATO-III in vitro. Methods: KATO-III gastric carcinoma cells were treated with a range of concentrations of bromelain and/or NAC. The effect of the single agent or combination therapy on the growth and proliferation of the cancer cells was determined after 72 hours of treatment using sulforhodamine B assay. A similar method was employed to assess any possible synergism when the treatment was combined with chemotherapy. Results: We observed that bromelain, at the concentration of 200 μg/ml, and NAC, at the concentration of 25 mM, significantly inhibited the cell proliferation (p-values of <0.0001 and 0.0095, respectively). When combined together, synergistic effects of the combination therapy was evident. In addition, we examined if the treatment was capable of potentiating the cytotoxic effects of chemotherapy. Cytotoxicity of single agent cisplatin, paclitaxel, 5-fluorouracil and vincristine was compared against that of their combination with bromelain/NAC. Our results indicated a higher potency of each drug when used in combination with bromelain/NAC. Conclusion: In the present study, we showed that the utility of bromelain and N-acetylcysteine, as single agent or in combination, yields cytotoxic effects in the gastric carcinoma cell line KATO-III and potentiates chemotherapy. Afshin Amini et al., J Cancer Sci Ther 2013, 5:10 http://dx.doi.org/10.4172/1948-5956.S1.029