Vol 3, No 2 (2016)

Advances in Molecular Oncology. 2016;3(2):8-17

8-17

Genetic and epigenetic mechanisms of regulation of human papillomavirus

Vinokurova S.V.

Abstract

Infections with high-risk human papillomaviruses (HPV) are the etiological factor of certain types of human cancers in anogenital tract and head and neck cancers. Extensive epidemiological studies demonstrated the association of persistent high-risk HPV infection and the later development of cervical and other cancers. Experimental data using cell lines models and cervical cancers demonstrate that in more than 99 % of clinical samples the viral E6 and E7 genes are retained and expressed. These genes can transform human cells and inhibition of their expression in cancer cells results in loss of neoplastic growth properties. Molecular mechanisms of immortalization and transformation by E6 and E7 have extensively been investigated. However, the mechanism of E6 and E7 deregulation that triggers the shift from permissive infection to neoplastic transforming infection is still unclear. This review describes the current knowledge about the viral life cycle and discusses the molecular mechanisms that potentially allow the virus to escape its normal control and may trigger neoplastic progression. The molecular clarification of these events required for transformation of HPV-infected cells into cancer will provide a basis for conceptually novel diagnostic and therapeutic strategies and approaches.

Advances in Molecular Oncology. 2016;3(2):18-25

18-25

Tumor stem cells from glioblastoma multiforme

Nikiforova Z.N., Kudryavtsev I.A., Arnotskaya N.E., Bryukhovetskiy I.S., Shevchenko V.E.

Abstract

Glioblastoma multiforme, a World Health Organization grade IV malignant glioma, is the most common and lethal primary brain tumor with the median survival of approximately 15–25 months after treatment. Glioblastoma multiforme has been shown to be resistant to radiotherapy and chemotherapy and invariably recurs following surgical resection and chemoradiation. The characteristics of this tumor are exemplified by heterogeneous cell population with diverse biologic properties and genetic changes, the ability to form cancer stem cells (CSC) and divided into four molecular subtypes – proneural, neural, classical and mesenchymal. Despite some success, the mechanisms leading to the formation of the most malignant tumor subtype are unclear. The aim of this review was a synthesis of modern information about the role and biological characteristics of tumor stem cells in tumor progression and the pathogenesis of glioblastoma multiforme. CSCs reside in niches, which are anatomically distinct regions within the tumor microenvironment. These niches maintain the principle properties of CSCs, preserve their phenotypic plasticity, adhesion, survival, resistance to standard cancer treatment and metastatic potential. The presence of aberrant signaling pathways (Notch, Hedgehog-Gli, Wnt/β-catenin, TGF-β/SMAD, PI3K/Akt/mTOR), both in the tumor and in the population of CSC, the dysregulation of microRNAs (miR-21, miR-128, miR-326, miR-34a), influence of epithelial-to-mesenchymal transition explains the availability of typical biological characteristics of the CSC. One needs to consider the influence of the therapy on normal stem cells in the development of drugs directed against the CSC. Regulatory mechanisms and markers found over the last decade can be used as the basis for creation of the new drugs with targeted action in the treatment of glioblastoma multiforme.

Advances in Molecular Oncology. 2016;3(2):26-33

26-33

RESEARCH ARTICLES

The study of new anticancer drug delivery system based on the boron nitride nanoparticles

Zhitnyak I.Y., Sukhorukova I.V., Koval’skiy A.M., Matveev A.T., Bychkov I.N., Shtanskiy D.V., Glushankova N.A.

Abstract

The main problem in the treatment of many cancers is multidrug resistance due to tumor progression. Using nanosized drug delivery systems allows to overcome the mechanisms of multidrug resistance of cancer, in this case, chemotherapeutic agents can effectively introduce into cancer cells by endocytosis and accumulate near the nucleus and far from ATP-binding cassette transporters. Creation of boron nitridebased drug delivery nanocarriers with high chemical and oxidative stability is one of the perspective ways. Using chemical vapor deposition spherical boron nitride particles,100–150 nm in diameter (BNNPs), with peculiar petal-like surfaces or smooth surfaces were fabricated. BNNPs were loaded with doxorubicin. Drug loading efficacy of BNNPs-DOX was about 0.095 mg/mg of particles. BNNPs-DOX were relatively stable at neutral pH, whereas DOX is effectively released from the BNNPs at acidic pH (pH 4.5–5.5). Using confocal microscopy, the uptake of BNNPs-DOX by IAR-6-1, KB-3-1, К562 cells and multidrug resistant КВ-8-5 и IS-9 cells was studied. Most of BNNPs-DOX had been co-localized with LysoTracker, indicating that BNNPs-DOX are located in the endosomes/lysosomes after intracellular delivery.

Advances in Molecular Oncology. 2016;3(2):34-41

34-41

Highly sensitive scanning of gene mutations: TaqMan probes as blocking agents

Botezatu I.V., Panchuk I.O., Stroganova A.M., Senderovich A.I., Kondratova V.N., Shelepov V.P., Liсhtenshtein A.V.

Abstract

DNA Melting Analysis is very effective in clinical DNA diagnostics: it is simple to perform, high throughput, labor-, time- and cost-effective and is implemented in the “closed tube” format minimizing the risk of samples cross-contamination. Although more sensitive than sequencing by Sanger (mutant allele detection limit is ~5 and ~15 % respectively), it, however, is inferior in this respect to some other, more laborious and expensive methods (in particular, ddPCR (digital droplet PCR)). Using the BRAF gene as a prototype, we developed the original version of the DNA melting analysis, based on the ability of TaqMan probes to hamper the primer extension reaction by Taq-polymerase. It is found that the weaker blocking effect on the mutant template, which is due to the mismatch in the probe-DNA heteroduplex, permits enriched amplification of the mutant allele and provides a significant (10-fold or more) increase in sensitivity of mutation scanning.

Advances in Molecular Oncology. 2016;3(2):42-49

42-49

Molecular determinants of transforming growth factor beta-1 action on human glioblastoma cells

Shevchenko V.E., Kovalev S.V., Arnotskaya N.E., Nikiforova Z.N., Kudryavtsev I.A., Savchenko E.A., Bryukhovetskiy I.S.

Abstract

Background. Increased expression of transforming growth factor beta-1 (TGF-β1) in malignant brain tumors promotes cancer cells survival enhancing their growth, migration, invasion, angiogenesis, immune system suppression.

Objective is to study molecular mechanisms of TGF-β1 action on U87 human glioblastoma cells by means of proteomic high-resolution massspectrometry.

Results. We have identified intracell signal pathways responsible for TGF-β1 involvement in malignant gliomas oncogenesis including differential expressed proteins of tight cell junctions, focal adhesion, histone deacetylases, heat shock, S100 family.

Conclusions. Important patterns are determined that could be used for the development of new approaches for detection of glioblastoma metastasis candidate markers and potential therapy targets of this decease.

Advances in Molecular Oncology. 2016;3(2):50-59

50-59