Jana Merhautová

miR-155 and miR-484 Are Associated with Time to Progression in Metastatic Renal Cell Carcinoma Treated with Sunitinib

Background. Sunitinib is a tyrosine kinase inhibitor used in the treatment of metastatic renal cell carcinoma. The main difficulty related to the treatment is the development of drug resistance followed by rapid progression of the disease. We analyzed tumor tissue of sunitinib treated patients in order to find miRNAs associated with therapeutic response. Methods. A total of 79 patients with metastatic renal cell carcinoma were included in our study. miRNA profiling in tumor tissue samples was performed by TaqMan Low Density Arrays and a group of selected miRNAs (miR-155, miR-374-5p, miR-324-3p, miR-484, miR-302c, and miR-888) was further validated by qRT-PCR. Normalized data were subjected to ROC and Kaplan-Meier analysis. Results. We reported decreased tissue levels of miR-155 and miR-484 as significantly associated with increased time to progression (miR-155: median TTP 5.8 versus 12.8 months, miR-484: median TTP 5.8 versus 8.9 months). Conclusion. miR-155 and miR-484 are potentially connected with sunitinib resistance and failure of the therapy. miR-155 is a known oncogene with direct influence on neovascularization. Biological role of miR-484 has to be clarified. Stratification of patients based on miRNA analysis would allow more personalized approach in therapy of metastatic renal cell carcinoma.

MicroRNA-Based Therapy in Animal Models of Selected Gastrointestinal Cancers

Gastrointestinal cancer accounts for the 20 most frequent cancer diseases worldwide and there is a constant urge to bring new therapeutics with new mechanism of action into the clinical practice. Quantity of in vitro and in vivo evidences indicate, that exogenous change in pathologically imbalanced microRNAs (miRNAs) is capable of transforming the cancer cell phenotype. This review analyzed preclinical miRNA-based therapy attempts in animal models of gastric, pancreatic, gallbladder, and colorectal cancer. From more than 400 original articles, 26 was found to assess the effect of miRNA mimics, precursors, expression vectors, or inhibitors administered locally or systemically being an approach with relatively high translational potential. We have focused on mapping available information on animal model used (animal strain, cell line, xenograft method), pharmacological aspects (oligonucleotide chemistry, delivery system, posology, route of administration) and toxicology assessments. We also summarize findings in the field pharmacokinetics and toxicity of miRNA-based therapy.

MiR-215-5p is a tumor suppressor in colorectal cancer targeting EGFR ligand epiregulin and its transcriptional inducer HOXB9

Growing evidence suggests that microRNAs are involved in the development and progression of colorectal cancer (CRC). In the present study, deregulation and functioning of tumor-suppressive miR-215-5p was evaluated in CRC. In total, 448 tumor tissues and 325 paired adjacent healthy tissues collected from Czech and Spain cohorts of CRC patients have been used for miR-215-5p expression analyses. A series of in vitro experiments have been performed using transient transfection of miR-215-5p mimics into four CRC cell lines to identify specific cellular processes affected by miR-215-5p. Further, the effects of miR-215-5p on tumor growth were evaluated in vivo using NSG mice and stable cell line overexpressing miR-215-5p. Target mRNAs of miR-215-5p were tested using luciferase assay and western blot analyses. We found that miR-215-5p is significantly downregulated in tumor tissues compared with non-tumor adjacent tissues and its decreased levels correlate with the presence of lymph node metastases, tumor stage, and shorter overall survival in CRC patients. Overexpression of miR-215-5p significantly reduced proliferation, clonogenicity, and migration of CRC cells, lead to cell cycle arrest in G2/M phase and p53-dependent induction of apoptosis. The ability of miR-215-5p to inhibit tumor growth was confirmed in vivo. Finally, we confirmed epiregulin and HOXB9 to be the direct targets of miR-215-5p. As epiregulin is EGFR ligand and HOXB9 is its transcriptional inducer, we suggest that the main molecular link between miR-215-5p and CRC cells phenotypes presents the EGFR signaling pathway, which is one of the canonical pathogenic pathways in CRC.

Abstract 3425: MiR-215-5p is a tumor suppressor in colorectal cancer targeting EGFR ligand epiregulin and its transcriptional inducer HOXB9

Growing evidence suggests that microRNAs (miRNAs) are involved in the development and progression of colorectal cancer (CRC). In the present study, deregulation and functioning of tumor suppressive miR-215-5p was evaluated in CRC. In total, 448 tumor tissues and 325 paired adjacent healthy tissues have been used for miRNA expression analyses. We proved that miR-215-5p is significantly down-regulated in tumor tissues compared to non-tumor adjacent tissues and its decreased levels correlate with the presence of lymph node metastases, tumor stage, and shorter overall survival in CRC patients. To identify specific cellular processes affected by ectopic expression of miR-215-5p, a series of in vitro experiments have been performed using transient transfection of miR-215-5p mimics into four CRC cell lines. Increased levels of miR-215-5p significantly reduced proliferation, clonogenicity, and migration of CRC cells, lead to cell cycle arrest in G2/M phase and p53-dependent induction of apoptosis. The ability of miR-215-5p to inhibit tumor growth was confirmed in vivo by use of NSG mice model and stable cell line over-expressing miR-215-5p. Finally, we proved epiregulin and HOXB9 to be the direct targets of miR-215-5p by luciferase assay and western blot analyses. Since epiregulin is EGFR ligand and HOXB9, is its transcriptional inducer, we suggest, that the main molecular link between miR-215-5p and CRC cells phenotypes presents the EGFR signaling pathway, which is one of the canonical pathogenic pathways in CRC. This work was supported by Ministry of Health of the Czech Republic, grant nr. 15-33158A, 15-34553A, 15-31627A, 15-34678A, 16-31314A, 16-31765A and by grant of Czech Grant Agency nr. 16-18257S. Citation Format: Petra Faltejskova-Vychytilova, Jana Merhautova, Pablo Conesa-Zamora, Katerina Slaba, Tana Machackova, Marek Svoboda, Marek Vecera, Jitka Mlcochova, Jaroslav Juracek, Jiri Sana, Parwez Ahmad, Natalia Gablo, Ondrej Slaby. MiR-215-5p is a tumor suppressor in colorectal cancer targeting EGFR ligand epiregulin and its transcriptional inducer HOXB9 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3425. doi:10.1158/1538-7445.AM2017-3425

Olfactory bulbectomy increases reinstatement of methamphetamine seeking after a forced abstinence in rats

Drug addiction is commonly associated with depression and comorbid patients also suffer from higher cravings and increased relapse rate. To address this issue preclinically we combined the olfactory bulbectomy (OBX) model of depression and intravenous methamphetamine self-administration procedure in rats to assess differences in relapse-like behavior. Male Sprague-Dawley rats were divided randomly into two groups; in one group the bilateral olfactory bulbectomy (OBX) was performed while the other group was sham operated. After recovery, intracardiac catheter was implanted. Intravenous self-administration procedure was conducted in operant boxes using nose-poke operandi (Coulbourn Instruments, Inc., USA) under fixed ratio 1 schedule of reinforcement. Methamphetamine was available at dose 0.08 mg/kg/infusion. After stable methamphetamine intake was maintained, a period of forced abstinence was initiated and rats were kept in their home-cages for 14 days. Finally, one reinstatement session was conducted in operant boxes with no drug delivery. In the reinstatement session the mean of 138.4 active nose-pokes was performed by the OBX group, while the sham group displayed 41 responses, i.e. 140 % and 48 % of basal nose-poking during maintenance phase in OBX and sham operated group respectively. OBX group also showed significantly more passive nose-pokes indicating hyperactive behavioral traits in bulbectomized rats. However, the % of active operandum preference was equal in both groups. Olfactory bulbectomy model significantly increased reinstatement of methamphetamine seeking behavior. This paradigm can be used to evaluate potential drugs that are able to suppress the drug-seeking behavior.