e13545 Background: MM-D37K is a synthetic peptide which consists of p16INK4a-specific inhibitor of complex cyclin D- CDK4 and CDK6 and cell penetrating peptide (CPP) – Antp (Penetratin). We investigated in vitro and in vivo cytotoxic, cytostatic and antitumor activity of MM-D37K. The level of cyclin A, Ki67,bax, bcl-2 and pRb phosphorylation was investigated. Full range of Toxicology tests and Pharmacokinetics experiments in mice, rats and rabbits were performed. Methods: Different cell lines (Jurcat, Raji, A549, MCF-7, Hct-116, Ht-29, HEK293) were incubated with 0.1-100 mM MM-D37K for 24-48 hrs. Proliferation (MTT), DNA-content, cell cycle (flow cytometry) and mRNA level of appropriate proteins (RT PCR) were investigated. In vivo experiments were conducted on xenograft model of HCT116, A-549 at concentration 5 and 10 mg/kg of MM-D37K. Toxicology experiments were made under RF Law and included 3 types of animals. LC-MS MMD37K method of detection in plasma was developed. Results: MM-D37K prevented pRb phosphorilation and proliferation activation in all investigated cell lines. Cell cycle was blocked in G1 phase. Cytostatic effect did not depend on p16 mutation or expression. MM-D37K induced apoptosis in 20-82% of investigated cells at 40 mM with lowest level for MCF-7. LD10 for rats was 100 mg/kg and no deaths were registered for rabbits (highest dose was 50 mg/kg). Concentration of MMD-37K in plasma after 2 min and bolus i.v. injection in dose 10 mg/kg was 72.16±5.64 mcg/ml. Concentration decreased in two phases. 1st – t1/2 = 2.39±0.39 min and for 2nd t1/2=2.39±0.39 hr. Antitumor effects in xenograft model were 53% for A-549 and 67% for HCT116. Conclusions: Our results proved cytotoxic, cytostatic and antitumor effects of MM-D37K in investigated cell lines in vitro and in vivo. Toxicological and pharmacokinetics results allow us recommend for I/IIa Phase clinical trial. (Support: MetaMax Ltd., RFFI, Minpromtorg RF.)

Currently, no molecular biological markers do exist for early diagnosis of breast cancer. One of the possible candidates for the marker of early breast cancer is mammaglobin (MGB1) or SCGB2A2 (secretoglobin, family 2A, member 2), characterized by the maximal expression level in early breast cancer. Using the RT-PCR method MGB1 mRNA expression was examined in 57 tumor tissue samples and 57 samples of morphologically non-malignant tissue (MNT) of breast cancer (BC) patients. Specificity and sensitivity of the MGB1 mRNA assay in peripheral blood of BC patients was evaluated by nested PCR. 169 blood samples (from 95 BC patients, 22 from patients with benign breast tumors, 28 from patients with tumors of other localizations, and 24 samples from healthy donors) have been analyzed. MGB1 expression was significantly higher in BC tissue samples compared to MNT (p=0.0019). The maximal expression level was in the samples T1 (p=0.013), stage I BC (p=0.037), GI (p=0.0019). The MGB1 expression positively correlated with expression of estrogen (p = 0,034) and progesterone (p=0.0004) receptors. Sensitivity and specificity of the MGB1 mRNA assay in peripheral blood were 60.6% and 92.3%, respectively. Expression of MGB1 was higher in BC than MNT and it decreased during BC progression. The sensitivity and specificity of the MGB1 mRNA assay may be used as an additional diagnostic method.

The goal of this work is the development of novel peptides with high efficacy of inhibiting activity of CDK6/CyclinD complex. The peptides were derived from primary sequence of P16 protein and its homologues. The interactions between CDK6 and P16/INK4a-derived peptides are studied with molecular dynamics simulation employing umbrella sampling method. The SASA implicit solvent model was used for simulation, which was accelerated using NVIDIA GPUs.

Introduction: Breast cancer (BC) diagnostics lack noninvasive methods and procedures for screening and monitoring disease dynamics. Admitted CellSearch® is used for fluid biopsy and capture of circulating tumor cells of only epithelial origin. Here we describe an RNA aptamer (MDA231) for detecting BC cells in clinical samples, including blood. The MDA231 aptamer was originally selected against triple-negative breast cancer cell line MDA-MB-231 using cell-SELEX.Methods: The aptamer structure in solution was predicted using mFold program and molecular dynamic simulations. The affinity and specificity of the evolved aptamers were evaluated by flow cytometry and laser scanning microscopy on clinical tissues from breast cancer patients. CTCs were isolated form the patients’ blood using the developed method of aptamer-based magnetic separation. Breast cancer origin of CTCs was confirmed by cytological, RT-qPCR and Immunocytochemical analyses.Results: MDA231 can specifically recognize breast cancer cells in surgically resected tissues from patients with different molecular subtypes: triple-negative, Luminal A, and Luminal B, but not in benign tumors, lung cancer, glial tumor and healthy epithelial from lungs and breast. This RNA aptamer can identify cancer cells in complex cellular environments, including tumor biopsies (e.g., tumor tissues vs. margins) and clinical blood samples (e.g., circulating tumor cells). Breast cancer origin of the aptamer-based magnetically separated CTCs has been proved by immunocytochemistry and mammaglobin mRNA expression.Discussion: We suggest a simple, minimally-invasive breast cancer diagnostic method based on non-epithelial MDA231 aptamer-specific magnetic isolation of circulating tumor cells. Isolated cells are intact and can be utilized for molecular diagnostics purposes.

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Despite the sufficient amount of data accumulated in the literature, there are still no factors, on the basis of which it would be possible to estimate the regional lymph nodes status in breast cancer with a high degree of accuracy. The review presents literature data relating to the influence of clinicopathological, molecular-biological and genetic characteristics of primary tumor on lymph node metastases. Data of 66 foreign and Russian articles are included.

Ispol'zovanie «standartnyh» diagnosticheskih panelej, dayushchih vozmozhnost' opredelyat' lish' neskol'ko naibolee rasprostranennyh v populyacii mutacij v genah BRCA1 i BRCA2, mozhet privodit' k poyavleniyu lozhnootricatel'nyh rezul'tatov iz-za nalichiya drugih povrezhdenij v kodiruyushchih oblastyah dannyh genov, chto, v svoyu ochered', mozhet privesti k neadekvatnomu vyboru taktiki lecheniya u bol'nyh rakom molochnoj zhelezy (RMZH). Cel'yu raboty bylo vyyavit' osobennosti BRCA-associirovannogo raka molochnoj zhelezy v rossijskoj populyacii. V issledovanie voshli pacienty s diagnozom RMZH (n = 4440). Na pervom etape metodom PCR v real'nom vremeni provedeno skriningovoe issledovanie vsekh pacientov na nalichie vos'mi naibolee rasprostranennyh mutacij v genah BRCA1 i BRCA2. Dalee pri nalichii u pacientov klinicheskih priznakov nasledstvennogo zabolevaniya (KPNZ) i otsutstvii rasprostranennyh mutacij (n = 290) provodili issledovanie vsej kodiruyushchej chasti genov BRCA1 i BRCA2 metodom sekvenirovaniya novogo pokoleniya (NGS). V 169 sluchayah (3,8%) byli vyyavleny «standartnye» mutacii v genah BRCA1 i BRCA2. V gruppe pacientov s KPNZ chastota vyyavlennyh «standartnyh» mutacij sostavila 15,4%. Metodom NGS u 40 iz 290 bol'nyh RMZH (13,8%) byli obnaruzheny 33 redkie patogennye mutacii v genah BRCA1 i BRCA2. Sdelan vyvod, chto BRCA-associirovannyj RMZH v rossijskoj populyacii harakterizuetsya shirokim spektrom patogennyh variantov, kotoryj ne ogranichen mutaciyami, vklyuchennymi v standartnye kliniko-diagnosticheskie paneli. Analiz vsej kodiruyushchej chasti genov BRCA1 i BRCA2 pozvolyaet povysit' effektivnost' vyyavleniya germinal'nyh mutacij u bol'nyh RMZH po krajnej mere v 2 raza.

Introduction. Currently, there are conflicting data regarding the effect of the c.470T> C germline mutation in the CHEK2 gene on increasing the risk of breast cancer (BC), so it is necessary to conduct research on large samples of patients, including in the Russian population, in order to analyze the contribution of this mutation to the risk of cancer developing.The aim of the study was to determine the frequency of occurrence of the genetic variant c.470Т>С in the CHEK2 gene in the Russian population in patients with BC and patients with benign breast diseases (BBD) to assess the possible effect of this deoxyribonucleic acid damage on the likelihood of cancer occurrence.Materials and methods. The study included 2,787 patients with BC and 1,004 patients with BBD who underwent examination and treatment at the Russian Scientific Center of Roentgenoradiology of the Ministry of the Russian Federation from 2010 to 2018. Molecular genetic study was carried out by real-time polymerase chain reaction to determine the characteristic of the Russian population hereditary genetic variant c.470Т>С in the CHEK2 gene using a diagnostic panel that allows to determine three germline mutations: c.1100delC, c.444+1G>A and c.470Т>С in the CHEK2 gene.Results. In patients with BC the frequency of the mutation c.470T>C in the CHEK2 gene was 3.8 %, in patients with BBD this mutation was detected in 4.7 % of cases. The frequency of the genetic variant c.470T>C in high-risk groups was: 5.1 % – for BC patients with clinical signs of hereditary disease and 4.9 % – for patients with BBD with a family history of cancer. There were no statistically significant differences between the frequency of the mutation c.470T>C in the general groups of BC patients and patients with BBD and the corresponding frequency in the high-risk groups, as well as in the groups of BC patients and patients with BBD (p >0.05).Conclusion. The results of this study indicate the probable absence of a relationship between the presence of the mutation c.470Т>С in the CHEK2 gene and an increased risk of BC.