1. Aberrantly expressed hsa_circ_0060762 and CSE1L as potential peripheral blood biomarkers for ALSMetka Ravnik-Glavač, Massimo Mezzavilla, Ana Dolinar, Blaž Koritnik, Damjan Glavač, 2023, original scientific article Abstract: Amyotrophic lateral sclerosis (ALS) is a rapidly progressive adult-onset neurodegenerative disease that is often diagnosed with a delay due to initial non-specific symptoms. Therefore, reliable and easy-to-obtain biomarkers are an absolute necessity for earlier and more accurate diagnostics. Circular RNAs (circRNAs) have already been proposed as potential biomarkers for several neurodegenerative diseases. In this study, we further investigated the usefulness of circRNAs as potential biomarkers for ALS. We first performed a microarray analysis of circRNAs on peripheral blood mononuclear cells of a subset of ALS patients and controls. Among the differently expressed circRNA by microarray analysis, we selected only the ones with a host gene that harbors the highest level of conservation and genetic constraints. This selection was based on the hypothesis that genes under selective pressure and genetic constraints could have a major role in determining a trait or disease. Then we performed a linear regression between ALS cases and controls using each circRNA as a predictor variable. With a False Discovery Rate (FDR) threshold of 0.1, only six circRNAs passed the filtering and only one of them remained statistically significant after Bonferroni correction: hsa_circ_0060762 and its host gene CSE1L. Finally, we observed a significant difference in expression levels between larger sets of patients and healthy controls for both hsa_circ_0060762 and CSE1L. CSE1L is a member of the importin β family and mediates inhibition of TDP-43 aggregation; the central pathogenicity in ALS and hsa_circ_0060762 has binding sites for several miRNAs that have been already proposed as biomarkers for ALS. In addition, receiver operating characteristics curve analysis showed diagnostic potential for CSE1L and hsa_circ_0060762. Hsa_circ_0060762 and CSE1L thus represent novel potential peripheral blood biomarkers and therapeutic targets for ALS.
Keywords: amyotrophic lateral sclerosis, ALS, circRNA, biomarker, peripheral blood biomarker, hsa_circ_0060762, CSE1L, biomedicine
Published in DiRROS: 12.07.2024; Views: 47; Downloads: 24
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2. Dynamic expression of 11 miRNAs in 83 consecutive primary and corresponding recurrent glioblastoma : correlation to treatment, time to recurrence, overall survival and MGMT methylation statusBoštjan Matos, Emanuela Boštjančič, Alenka Matjašič, Mara Popović, Damjan Glavač, 2018, original scientific article Abstract: Background. Glioblastoma (GBM) is the most common and the most malignant glioma subtype. Among numerous genetic alterations, miRNAs contribute to pathogenesis of GBM and it is suggested that also to GBM recurrence and resistance to therapy. Based on publications, we have selected 11 miRNAs and analyzed their expression in GBM. We hypothesized that selected miRNAs are differentially expressed and involved in primary as well as in recurrent GBM, that show significant expressional differences when different treatment options are in question, and that are related to certain patients and tumor characteristics. Patients and methods. Paraffin embedded tissues, obtained from primary and corresponding recurrent tumor from 83 patients with primary GBM were used. Eleven miRNAs ( miR-7, miR-9, miR-15b, miR-21, miR-26b, miR-124a, miR-199a, let-7a, let-7b, let-7d, and let-7f ) were selected for qPCR expression analysis. For patients who received temozolamide (TMZ) as chemotherapeutic drug, O6-methylguanine-DNA methyltransferase (MGMT) methylation status was defined using the methyl-specific PCR. Results. There was a significant change in expression of miR-7, miR-9, miR-21, miR-26b, mirR-124a, miR-199a and let- 7f in recurrent tumor compared to the primary. In recurrent tumor, miR-15b, let-7d and let-7f significantly changed comparing both treatment options. We also observed difference in progression free survival between patients that received radiotherapy and patients that received radiotherapy and chemotherapy, and longer survival for patients who received chemotherapy after second surgery compared to not treated patients. miR-26b showed correlation to progression free survival and let-7f to overall survival. We did not find any expression difference between the tumors with and without methylated MGMT. Conclusions. Our data suggest that analyzed miRNAs may not only contribute to pathogenesis of primary GBM, but also to tumor progression and its recurrence. Moreover, expression of certain miRNAs appears to be therapy- dependent and as such they might serve as additional biomarker for recurrence prediction and potentially predict a therapy-resistance.
Keywords: glioblastoma, radiotherapy, chemotherapy
Published in DiRROS: 02.07.2024; Views: 117; Downloads: 59
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3. Expression of LOC285758, a potential long non-coding biomarker, is methylation- dependent and correlates with glioma malignancy gradeAlenka Matjašič, Mara Popović, Boštjan Matos, Damjan Glavač, 2017, original scientific article Abstract: Background. Identifying the early genetic drivers can help diagnose glioma tumours in their early stages, before becoming malignant. However, there is emerging evidence that disturbance of epigenetic mechanisms also con- tributes to cell's malignant transformation and cancer progression. Long non-coding RNAs are one of key epigenetic modulators of signalling pathways, since gene expression regulation is one of their canonical mechanisms. The aim of our study was to search new gliomagenesis-specific candidate lncRNAs involved in epigenetic regulation. Patients and methods. We used a microarray approach to detect expression profiles of epigenetically involved lncRNAs on a set of 12 glioma samples, and selected LOC285758 for further qPCR expression validation on 157 glioma samples of different subtypes. To establish if change in expression is a consequence of epigenetic alterations we determined methylation status of lncRNA's promoter using MS-HRM. Additionally, we used the MLPA analysis for de- termining the status of known glioma biomarkers and used them for association analyses. Results. In all glioma subtypes levels of LOC285758 were significantly higher in comparison to normal brain reference RNA, and expression was inversely associated with promoter methylation. Expression substantially differs between astrocytoma and oligodendroglioma, and is elevated in higher WHO grades, which also showed loss of methylation. Conclusions. Our study revealed that lncRNA LOC285758 changed expression in glioma is methylation-dependent and methylation correlates with WHO malignancy grade. Methylation is also distinctive between astrocytoma I-III and other glioma subtypes and may thus serve as an additional biomarker in glioma diagnosis.
Keywords: glioma, epigenetics, methylation
Published in DiRROS: 03.06.2024; Views: 192; Downloads: 150
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4. Long-term survival in glioblastoma : methyl guanine methyl transferase (MGMT) promoter methylation as independent favourable prognostic factorUroš Smrdel, Mara Popović, Matjaž Zwitter, Emanuela Boštjančič, Andrej Zupan, Viljem Kovač, Damjan Glavač, Drago Bokal, Janja Jerebic, 2016, original scientific article Abstract: In spite of significant improvement after multi-modality treatment, prognosis of most patients with glioblastoma remains poor. Standard clinical prognostic factors (age, gender, extent of surgery and performance status) do not clearly predict long-term survival. The aim of this case-control study was to evaluate immuno-histochemical and genetic characteristics of the tumour as additional prognostic factors in glioblastoma. Long-term survivor group were 40 patients with glioblastoma with survival longer than 30 months. Control group were 40 patients with shorter survival and matched to the long-term survivor group according to the clinical prognostic factors. All patients underwent multimodality treatment with surgery, postoperative conformal radiotherapy and temozolomide during and after radiotherapy. Biopsy samples were tested for the methylation of MGMT promoter (with methylation specific polymerase chain reaction), IDH1 (with immunohistochemistry), IDH2, CDKN2A and CDKN2B (with multiplex ligation-dependent probe amplification), and 1p and 19q mutations (with fluorescent in situ hybridization). Methylation of MGMT promoter was found in 95% and in 36% in the long-term survivor and control groups, respectively (p < 0.001). IDH1 R132H mutated patients had a non-significant lower risk of dying from glioblastoma (p= 0.437), in comparison to patients without this mutation. Other mutations were rare, with no significant difference between the two groups. Molecular and genetic testing offers additional prognostic and predictive information for patients with glioblastoma. The most important finding of our analysis is that in the absence of MGMT promoter methylation, longterm survival is very rare. For patients without this mutation, alternative treatments should be explored.
Keywords: glioblastoma, long-term survival, methyl guanine methyl transferase, MGMT, prognostic factor
Published in DiRROS: 30.04.2024; Views: 201; Downloads: 192
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5. MicroRNAs and long non-coding RNAs : prospects in diagnostics and therapy of cancerNina Hauptman, Damjan Glavač, 2013, published scientific conference contribution Abstract: Background. Non-coding RNAs (ncRNAs) are key regulatory molecules in cellular processes, and are potentialbiomarkers in many diseases. Currently, microRNAs and long non-coding RNAs are being pursued as diagnostic andprognostic biomarkers, and as therapeutic tools in cancer, since their expression profiling is able to distinguish differentcancer types and classify their sub-types.Conclusions. There are numerous studies confirming involvement of ncRNAs in cancer initiation, development andprogression, but have only been recently identified as new diagnostic and prognostic tools. This can be beneficialin future medical cancer treatment options, since ncRNAs are natural antisense interactors included in regulationof many genes connected to survival and proliferation. Research is directed in development of useful markers fordiagnosis and prognosis in cancer and in developing new RNA-based cancer therapies, of which some are alreadyin clinical trials.
Keywords: microRNAs, long non-coding RNAs, biomarker
Published in DiRROS: 22.03.2024; Views: 248; Downloads: 173
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6. Assessment of the tumourigenic and metastatic properties of SK-MEL28 melanoma cells surviving electrochemotherapy with bleomycinVesna Todorović, Gregor Serša, Vid Mlakar, Damjan Glavač, Maja Čemažar, 2012, original scientific article Abstract: Background. Electrochemotherapy is a local treatment combining chemotherapy and electroporation and is highly effective treatment approach for subcutaneous tumours of various histologies. Contrary to surgery and radiation, the effect of electrochemotherapy on metastatic potential of tumour cells has not been extensively studied. The aim of the study was to evaluate the effect of electrochemotherapy with bleomycin on the metastatic potential of human melanoma cells in vitro. Materials and methods. Viable cells 48 hours after electrochemotherapy were tested for their ability to migrate and invade through Matrigel coated porous membrane. In addition, microarray analysis and quantitative Real-Time PCR were used to detect changes in gene expression after electrochemotherapy. Results. Cell migration and invasion were not changed in melanoma cells surviving electrochemotherapy.Interestingly, only a low number of tumourigenesis related genes was differentially expressed after electrochemotherapy. Conclusions. Our data suggest that metastatic potential of human melanoma cells is not affected by electrochemotherapy with bleomycin, confirming safe role of electrochemotherapy in the clinics.
Published in DiRROS: 21.03.2024; Views: 427; Downloads: 99
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