[New Approaches for Chemosensitivity Testing in Malignant Diseases]. / Nové moznosti testování chemosenzitivity u nádorových onemocnení.

BACKGROUND: Due to the irreplaceable role of chemotherapy in cancer treatment, research has focused on improving the efficacies of individual drugs and minimizing, or completely suppressing, their negative side effects. Based on long-term experience and the results of clinical trials, the selection of appropriate treatment is currently based on classical clinical diagnostic criteria, such as tumor size, grade, and the presence or absence of standard markers. However, complications arise due to variability between patients and tumor heterogeneity. Characterization of intratumoral heterogeneity and acquisition of more reliable drug performance indicators should improve personalized therapy. Development and selection of suitable models are therefore important issues in cancer research focused on predicting sensitivity to therapy. AIM: This work provides an overview of various chemosensitivity tests that have been previously employed and those that are currently used. Great emphasis is placed on comparing 2D and 3D cell culture models, since their importance and popularity are increasing. Particular attention is paid to in vivo systems, which have significantly improved recently and are tested in clinical trials to predict responses to therapy. CONCLUSION: This work provides a brief overview of chemosensitivity tests, focusing on the importance of individual tests and their application in decision-making and patient stratification to improve the clinical responses of patients and the development of targeted personalized therapy.Key words: cell culture techniques - personalized medicine - drug screening - biological models - tumor cell lines - carcinoma - cytotoxicity assays This work was supported by the project MEYSNPS I-LO1413 and GACR 17-05838S. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 21. 9. 2017Accepted: 20. 12. 2017.

Impaired pre-mRNA processing and altered architecture of 3' untranslated regions contribute to the development of human disorders.

The biological fate of each mRNA and consequently, the protein to be synthesised, is highly dependent on the nature of the 3' untranslated region. Despite its non-coding character, the 3' UTR may affect the final mRNA stability, the localisation, the export from the nucleus and the translation efficiency. The conserved regulatory sequences within 3' UTRs and the specific elements binding to them enable gene expression control at the posttranscriptional level and all these processes reflect the actual state of the cell including proliferation, differentiation, cellular stress or tumourigenesis. Through this article, we briefly outline how the alterations in the establishment and final architecture of 3' UTRs may contribute to the development of various disorders in humans.

The role of the 3' untranslated region in post-transcriptional regulation of protein expression in mammalian cells.

The untranslated regions (UTRs) at the 3'end of mRNA transcripts contain important sequences that influence the fate of mRNA and thus proteosynthesis. In this review, we summarize the information known to date about 3'end processing, sequence characteristics including related binding proteins and the role of 3'UTRs in several selected signaling pathways to delineate their importance in the regulatory processes in mammalian cells. In addition to reviewing recent advances in the more well known aspects, such as cleavage and polyadenylation processes that influence mRNA stability and location, we concentrate on some newly emerging concepts of the role of the 3'UTR, including alternative polyadenylation sites in relation to proliferation and differentiation and the recognition of the multi-functional properties of non-coding RNAs, including miRNAs that commonly target the 3'UTR. The emerging picture is of a highly complex set of regulatory systems that include autoregulation, cooperativity and competition to fine tune proteosynthesis in context-dependent manners.

The effect of cellular environment and p53 status on the mode of action of the platinum derivative LA-12.

In this study, we characterized the effects of LA-12 on tumor cell lines possessing wild type p53 and on p53-deficient/mutant cell lines and the results were compared to those obtained using cisplatin. We have determined changes of p53 levels, of its transcriptional activity, of its posttranscriptional modifications and the effect of the treatment on the cell cycle, on the induction of apoptosis and on gene expression. LA-12 induces weak accumulation of both transcriptionally active p53 tumor suppressor and of p21(WAF1/CIP1) protein. LA-12 and cisplatin also significantly differ in their effects on apoptosis and cell cycle and on gene expression spectra in studied cell lines. LA-12 induces higher apoptosis levels in comparison with those induced by cisplatin, especially in p53-deficient H1299 cells and in MCF-7DD cells with transcriptionally inactive p53. We suggest that LA-12-mediated apoptosis is not fully dependent on p53. This confirms the therapeutic potential of LA-12 as a more potent cytostatic agent for both tumor cells expressing wild type p53 and for p53-deficient or mutant cells.

Ferroptosis as a New Type of Cell Death and its Role in Cancer Treatment.

BACKGROUND: Ferroptosis is a recently discovered type of cell death. It is genetically, morphologically, and biochemically distinct from other types of programmed cell death, such as necrosis, apoptosis, and autophagy. The level of intracellular free iron and reactive oxygen species formation are important for ferroptosis activation, which can occur through either of two key inhibitory processes. The first one involves inhibition of cystine transfer into cells by the cystine/glutamate antiporter system (Xc-). Cystine serves as a precursor for the synthesis of glutathione, a major cellular antioxidant. The second one involves the inhibition of glutathione peroxidase 4, which protects cells from lipid peroxidation. Ferroptosis is associated with many metabolic disorders, including neurological diseases and cancer. Molecules involved in the activation of ferroptotic pathways are involved in protecting cells against stress conditions, and in the maintenance of nicotinamide adenine dinucleotide phosphate and glutathione levels, as well as iron homeostasis. Also important is the connection with autophagy, so called ferritinophagy, in which iron is released from lysosomes into the cytosol. Cascade reactions of free unstable iron atoms with other molecules result in the production of reactive oxygen species that initiate the cellular stress that triggers ferroptosis. In diseases such as cancer where cell death inducing mechanisms, including apoptosis, are usually suppressed by genetic changes, the induction of alternative pathways leading to cell death could provide an attractive treatment strategy. CONCLUSION: In recent years, research into new antimetastatic drugs has focused on the activation of alternative cell death pathways that might overcome disturbed metabolic processes inside cancer cells or the chemotherapy resistance acquired in the course of routine treatment. A number of molecules have been found to induce ferroptosis in tumor cells, suggesting that they may offer new alternatives for anticancer treatment. Key words: cell death - cancer - autophagy - ferroptosis - ferritinophagy - cellular stress - ROS This work was supported by the projects GAČR 17-05838S, MEYS - NPS I - LO1413 and MH CZ- -DRO (MMCI, 00209805). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Accepted: 31. 8. 2018.

Acetylsalicylic Acid and its Potential for Chemoprevention of Colorectal Carcinoma.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAID) represent a group of medicaments inhibiting cyclooxygenase (COX) enzyme, and, in parallel, these drugs show also analgesic, antipyretic and anti-inflammatory effects. Due to their efficiency, good tolerance and easy availability, they belong to the worlds most used drugs. For decades, evidence of their anti-tumor activity has been growing, with the largest amount of published work being related to colorectal cancer (CRC). Based on both in vitro and in vivo experiments and data obtained from epidemiological and clinical studies, potential application of NSAID as chemo-preventive treatment for CRC patients is recently discussed in order to prevent development or recurrence of precanceroses and tumors. Promising treatment for such indication would be acetylsalicylic acid (ASA), which is the oldest, more than 100 years used member of the NSAID family. Nonselective irreversible COX inhibition is an important but probably not solely mechanism of its anticancer activity. Notably, wider use of ASA in chemoprevention is also prevented due to particular concerns about gastrointestinal and renal toxicity caused especially by its long-term use. AIMS: This review introduces the role of COX in tumor biology of CRC and highlights the results of the most interesting experiments illustrating the anti-tumor effect of ASA. Moreover, our work evaluates the most important published clinical analyzes of the ASA chemopreventive effect on CRC and discusses the current state. Key words: non-steroidal anti-inflammatory agents - acetylsalicylic acid - colorectal carcinoma - cyclooxygenase - chemoprevention This work was supported by the projects MEYS - NPS I - LO1413, MH CZ - DRO (MMCI, 00209805) and by Czech Science Foundation project no. 16-14829S. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Accepted: 10. 9. 2017.

AGR2 oncoprotein inhibits p38 MAPK and p53 activation through a DUSP10-mediated regulatory pathway.

The tumor suppressor p53 plays a key role in malignant transformation and tumor development. However, the frequency of p53 mutations within individual types of cancer is different, suggesting the existence of other mechanisms attenuating p53 tumor suppressor activity. Changes in upstream regulators of p53 such as MDM2 amplification and overexpression, expression of viral oncoproteins, estrogen receptor signaling, or changes in p53 transcriptional target genes were previously described in wild-type p53 tumors. We identified a novel pathway responsible for attenuation of p53 activity in human cancers. We demonstrate that AGR2, which is overexpressed in a variety of human cancers and provides a poor prognosis, up-regulates DUSP10 which subsequently inhibits p38 MAPK and prevents p53 activation by phosphorylation. Analysis of human breast cancers reveals that AGR2 specifically provides a poor prognosis in ER+ breast cancers with wild-type p53 but not ER- or mutant p53 breast cancers, and analysis of independent data sets show that DUSP10 levels also have prognostic significance in this specific sub-group of patients. These data not only reveal a novel pro-oncogenic signaling pathway mediating resistance to DNA damaging agents in human tumors, but also has implications for designing alternative strategies for modulation of wild-type p53 activity in cancer therapy.