Biology subjects

Leonov, S. V.

Publications and source records attributed to Leonov, S. V..

3 recordsLinked to original sources

bioRxiv2025

The Small Non-coding RNA miR-16-1-3p Hampers Cancer Stem Cell Self-renewal and Invasiveness, Boosting Chemosensitivity by Adjusting TGF-β1 Signaling via MDM2/p53 Axis in Human Osteosarcoma.

The TGF-{beta} signaling pathway has both tumor-suppressing and metastasis-promoting effects in cancer. However, the molecular determinants governing this switch remain unclear. Here, we explored the miR-16-1-3p/MDM2/p53 axis as a critical conductor of the TGF-{beta}-Smad pathway in osteosarcoma. Although miR-16-1-3p overexpression by itself markedly reduces proliferative and clonogenic potential of U2OS cells, when paired with TGF-{beta} treatment, it significantly increases arrest cells in G1 phase and nearly extinguishing the growth capability of these cells. MiR-16-1-3p overexpression inhibited TGF-induced actin remodeling and EMT featuring, significantly decreasing vimentin levels. TGF-{beta} enhances both 2D and 3D migration, but miR-16-1-3p overexpression, alone or with TGF-{beta}, strongly counteracts its pro-migratory effects. MiR-16-1-3p restored p53 stability by targeting MDM2, redirecting TGF-{beta}-Smad signaling toward p21 activation and proliferation inhibition while attenuating its EMT-promoting capacity. Administration of TGF-{beta} together with miR-16-1-3p dramatically increases the sensitivity of wild-type U2OS cells to cisplatin, exceeding that of TGF-{beta} therapy alone by more than an order of magnitude. Administering TGF-{beta} and miR-16-1-3p together significantly reduces the tumor nodule volume and Ki67 expression, while effectively eradicates metastases in the chicken chorioallantoic membrane (CAM) in vivo model. For the first time, our research demonstrates that miR-16-1-3p shifts TGF-{beta}1 signaling from a facilitator of metastasis to a promoter of anti-growth effects through MDM2 inhibition and p53 stabilization, effectively reducing the self-renewal and invasiveness of cancer stem cells in human osteosarcoma model. This process preserves TGF-{beta}s tumor-suppressive role while limiting its associated cancer risks.

cancer biology↗

bioRxiv2021

Comprehensive patient-level classification and quantification of driver events in TCGA PanCanAtlas cohorts

There is a growing need to develop novel therapeutics for targeted treatment of cancer. The prerequisite to success is the knowledge about which types of molecular alterations are predominantly driving tumorigenesis. To shed light onto this subject, we have utilized the largest database of human cancer mutations - TCGA PanCanAtlas, multiple established algorithms for cancer driver prediction (2020plus, CHASMplus, CompositeDriver, dNdScv, DriverNet, HotMAPS, OncodriveCLUSTL, OncodriveFML) and developed four novel computational pipelines: SNADRIF (Single Nucleotide Alteration DRIver Finder), GECNAV (Gene Expression-based Copy Number Alteration Validator), ANDRIF (ANeuploidy DRIver Finder) and PALDRIC (PAtient-Level DRIver Classifier). A unified workflow integrating all these pipelines, algorithms and datasets at cohort and patient levels was created. We have found that there are on average 12 driver events per tumour, of which 0.6 are single nucleotide alterations (SNAs) in oncogenes, 1.5 are amplifications of oncogenes, 1.2 are SNAs in tumour suppressors, 2.1 are deletions of tumour suppressors, 1.5 are driver chromosome losses, 1 is a driver chromosome gain, 2 are driver chromosome arm losses, and 1.5 are driver chromosome arm gains. The average number of driver events per tumour increases with age (from 7 to 15) and cancer stage (from 10 to 15) and varies strongly between cancer types (from 1 to 24). Patients with 1 and 7 driver events per tumour are the most frequent, and there are very few patients with more than 40 events. In tumours having only one driver event, this event is most often an SNA in an oncogene. However, with increasing number of driver events per tumour, the contribution of SNAs decreases, whereas the contribution of copy-number alterations and aneuploidy events increases. Author SummaryBy analysing genomic and transcriptomic data from 10000 cancer patients through our custom-built computational pipelines and previously established third-party algorithms, we have found that half of all driver events in a patients tumour appear to be gains and losses of chromosomal arms and whole chromosomes. We therefore suggest that future therapeutics development efforts should be focused on targeting aneuploidy. We have also found that approximately a third of driver events in a patient are whole gene amplifications and deletions. Thus, therapies aimed at copy-number alterations also appear very promising. On the other hand, drugs aiming at point mutations are predicted to be less successful, as these alterations are responsible for just a couple of drivers per tumour. One notable exception are patients having only one driver event in their tumours, as this event is almost always a single nucleotide alteration in an oncogene.

cancer biology↗

bioRxiv2019

Analysis of novel hyperosmotic shock response suggests \"beads in liquid\" cytosol structure

Proteins can aggregate in response to stresses, including hyperosmotic shock. Formation and disassembly of aggregates is a relatively slow process. We describe a novel instant response of the cell to hyperosmosis, during which chaperones and other proteins form numerous foci with properties uncharacteristic of classical aggregates. These foci appeared/disappeared seconds after shock onset/removal, in close correlation with cell volume changes. Genome-wide and targeted testing revealed chaperones, metabolic enzymes, P-body components and amyloidogenic proteins in the foci. Most of these proteins can form large assemblies and for some, the assembled state was pre-requisite for participation in foci. A genome-wide screen failed to identify genes whose absence prevented foci participation by Hsp70. Shapes of and interconnections between foci revealed by super-resolution microscopy indicated that the foci were compressed between other entities. Based on our findings, we propose a new model of the cytosol architecture as a collection of numerous of gel-like regions suspended in a liquid network. This network is reduced in volume in response to hyperosmosis and forms small pockets between the gel-like regions.

cell biology↗