P-TEFb promotes cell survival upon p53 activation by suppressing intrinsic apoptosis pathway.

Positive transcription elongation factor b (P-TEFb) is the crucial player in RNA polymerase II (Pol II) pause release that has emerged as a promising target in cancer. Because single-agent therapy may fail to deliver durable clinical response, targeting of P-TEFb shall benefit when deployed as a combination therapy. We screened a comprehensive oncology library and identified clinically relevant antimetabolites and Mouse double minute 2 homolog (MDM2) inhibitors as top compounds eliciting p53-dependent death of colorectal cancer cells in synergy with selective inhibitors of P-TEFb. While the targeting of P-TEFb augments apoptosis by anti-metabolite 5-fluorouracil, it switches the fate of cancer cells by the non-genotoxic MDM2 inhibitor Nutlin-3a from cell-cycle arrest to apoptosis. Mechanistically, the fate switching is enabled by the induction of p53-dependent pro-apoptotic genes and repression of P-TEFb-dependent pro-survival genes of the PI3K-AKT signaling cascade, which stimulates caspase 9 and intrinsic apoptosis pathway in BAX/BAK-dependent manner. Finally, combination treatments trigger apoptosis of cancer cell spheroids. Together, co-targeting of P-TEFb and suppressors of intrinsic apoptosis could become a viable strategy to eliminate cancer cells.

Targeting BRCA1 and BRCA2 Deficiencies with G-Quadruplex-Interacting Compounds.

G-quadruplex (G4)-forming genomic sequences, including telomeres, represent natural replication fork barriers. Stalled replication forks can be stabilized and restarted by homologous recombination (HR), which also repairs DNA double-strand breaks (DSBs) arising at collapsed forks. We have previously shown that HR facilitates telomere replication. Here, we demonstrate that the replication efficiency of guanine-rich (G-rich) telomeric repeats is decreased significantly in cells lacking HR. Treatment with the G4-stabilizing compound pyridostatin (PDS) increases telomere fragility in BRCA2-deficient cells, suggesting that G4 formation drives telomere instability. Remarkably, PDS reduces proliferation of HR-defective cells by inducing DSB accumulation, checkpoint activation, and deregulated G2/M progression and by enhancing the replication defect intrinsic to HR deficiency. PDS toxicity extends to HR-defective cells that have acquired olaparib resistance through loss of 53BP1 or REV7. Altogether, these results highlight the therapeutic potential of G4-stabilizing drugs to selectively eliminate HR-compromised cells and tumors, including those resistant to PARP inhibition.

Box-Behnken assisted development and validation of high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles.

While histone deacetylase inhibitors, such as vorinostat, demonstrate a significant effect against hematological cancers, their application for solid tumor treatment is limited. However, there is strong evidence that combinatorial administration of vorinostat and genotoxic agents (e.g., doxorubicin) enhances the antitumoral action of both drugs against tumors. We developed a high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles designed to provide the parenteral administration of both drugs and increase their safety profile. We performed separation on Nucleodur C-18 Gravity column with a mixture of 10 mM potassium dihydrogen phosphate buffer pH 3.9:ACN (90:10 v/v) as mobile phase at 240 nm. The method was linear within the concentration range of 4.2-52.0 µg/ml for both drugs with limits of detection and quantification of 3.5 and 10.7 µg/ml for doxorubicin and 2.5 and 7.7 µg/ml for vorinostat, respectively. The method was precise and accurate over the concentration range of analysis. Drug loading was 5.4% for doxorubicin and 0.8% for vorinostat. Degradation of doxorubicin after irradiation was less than 5%, while the amount of vorinostat decreased at 88% under the same conditions. Thus, the validated method could be adopted for routine simultaneous analysis of doxorubicin and vorinostat in polymeric nanoparticles.

Treatment challenges and health conditions among people living with HIV with or without substance use disorder in the Russian Federation.

We quantified treatment challenges faced by people living with HIV (PLHIV) in Russia. Cross-sectional data of 150 PLHIV in Russia were from the 2019 Positive Perspectives Survey. Mean age was 38.3 y. Two-thirds (68.0%[102/150]) had ever disguised their HIV pills, and 43.3%[65/150] said they would be stressed if someone saw their HIV pills. Overall, 14.7%[22/150] reported being ever diagnosed with substance use disorder (SUD). Self-rated optimal health was significantly lower among those with vs without a report of SUD on multiple health domains: sexual (40.9%[9/22] vs. 70.3%[90/128], p = 0.007), physical (22.7%[5/22] vs. 68.0%[87/128], p < 0.001), and overall health (27.3%[6/22] vs. 68.8%[88/128], p < 0.001). Those reporting SUD were more likely to miss HIV medication ≥ 1 time in the past month because they used recreational drugs (age and gender-adjusted prevalence ratio [APR] = 8.23, 95%CI = 6.99-9.68), could not afford their medication (APR = 3.28, 95%CI = 2.90-3.72), had to work (APR = 3.27, 95%CI = 2.97-3.60), or to avoid side effects (APR = 2.62, 95%CI = 2.37-2.89). Furthermore, self-reported SUD was strongly associated with numerous poor health conditions, including self-reported diagnosis of cancer (APR = 6.67, 95%CI = 5.24-8.48), mental illness (APR = 5.01, 95%CI = 4.53-5.55), and liver disease (APR = 4.29, 95%CI = 3.98-4.61). The distinct patterns of poorer health-related outcomes among PLHIV with SUD underscore the need to address behavioral and psychosocial challenges as part of holistic HIV care.

CLINICAL AND IMMUNOLOGICAL FEATURES OF ROTAVIRUS INFECTION IN CHILDREN INFECTED WITH EPSTEIN-BARR VIRUS.

OBJECTIVE: The aim: To identify clinical and immunological features of acute rotavirus gastroenteritis occurring against the background of Epstein-Barr virus infection. PATIENTS AND METHODS: Materials and methods: The study involved examination of 56 children. Of them, 33 children (1 group) did not have a background infection and 23 patients (2 group) suffered from rotavirus infection on the background of the latent form of Epstein-Barr virus infection. Children in these groups were compared by gender, age, severity of the disease and other parameters. Quantitative data were presented as mean and standard deviation (M±SD). Differences at p <0.05 were considered statistically significant. RESULTS: Results: The data suggest that the presence of background Epstein-Barr virus in children with rotavirus infection leads to later hospitalization, lower temperature response rates, lower frequency of vomiting at the onset of the disease, and longer duration of fever and diarrhea. At the same time, in children infected with Epstein-Barr virus, the relative content of CD8+ T lymphocytes dominated both in the acute period of the disease and in the period of convalescence against the background of reduced relative content of CD16+, CD22+ T lymphocytes and IgM in the period of early convalescence. CONCLUSION: Conclusions: The study allowed to reveal the influence of latent EBV infection on the clinical and immunological parameters of rotavirus gastroenteritis.

T-cell immunoglobulin and ITIM domain, as a potential immune checkpoint target for immunotherapy of colorectal cancer.

The importance of the tumor microenvironment in cancer progression has been well studied for many years. Immune checkpoint inhibitors (ICIs) are regarded as potential strategies in enhancing the immune responses in patients with cancer, particularly colorectal cancer (CRC). Notably, CRCs are extraordinarily heterogeneous and mostly are microsatellite-stable (MSS) or cold tumors, which means that the immune response is not usually as strong as that of foreign cells. T-cell immunoglobulin and ITIM domain (TIGIT) is a new immune checkpoint receptor overexpressed inside the CRC tumor-immune microenvironments. Moreover, several studies have shown that TIGIT in combination with other ICIs and/or conventional treatments, can lead to a robust anti-tumor response in CRC. This review looks deep inside TIGIT expression patterns, their various functions, and possible immunotherapy strategies to increase survival rates and decrease immune-related adverse events.

Indium iodide single crystal: breakthrough material for infrared acousto-optics.

Measurements of the refractive indices and the full set of longitudinal acousto-optical figures of merit in an orthorhombic single-crystal indium iodide (InI) were carried out. The high acousto-optic characteristics (M2 up to 1100×10-15s3kg-1) and strong optical anisotropy (Δn=0.47) make it possible to design various types of high-performance acousto-optic devices of the middle and far-infrared spectral range. In combination with a wide transparency range (0.62-51µm), the obtained characteristics make the crystal extremely promising in comparison with most existing analogs.

Route to hyperbolic hyperchaos in a nonautonomous time-delay system.

We consider a self-oscillator whose excitation parameter is varied. The frequency of the variation is much smaller than the natural frequency of the oscillator so that oscillations in the system are periodically excited and decayed. Also, a time delay is added such that when the oscillations start to grow at a new excitation stage, they are influenced via the delay line by the oscillations at the penultimate excitation stage. Due to nonlinearity, the seeding from the past arrives with a doubled phase so that the oscillation phase changes from stage to stage according to the chaotic Bernoulli-type map. As a result, the system operates as two coupled hyperbolic chaotic subsystems. Varying the relation between the delay time and the excitation period, we found a coupling strength between these subsystems as well as intensity of the phase doubling mechanism responsible for the hyperbolicity. Due to this, a transition from non-hyperbolic to hyperbolic hyperchaos occurs. The following steps of the transition scenario are revealed and analyzed: (a) an intermittency as an alternation of long staying near a fixed point at the origin and short chaotic bursts; (b) chaotic oscillations with frequent visits to the fixed point; (c) plain hyperchaos without hyperbolicity after termination visiting the fixed point; and (d) transformation of hyperchaos to the hyperbolic form.

Linear parabolic single-crystal diamond refractive lenses for synchrotron X-ray sources.

Linear parabolic diamond refractive lenses are presented, designed to withstand high thermal and radiation loads coming from upgraded accelerator X-ray sources. Lenses were manufactured by picosecond laser treatment of a high-quality single-crystal synthetic diamond. Twelve lenses with radius of curvature at parabola apex R = 200 µm, geometrical aperture A = 900 µm and length L = 1.5 mm were stacked as a compound refractive lens and tested at the ESRF ID06 beamline. A focal spot of size 2.2 µm and a gain of 20 were measured at 8 keV. The lens profile and surface quality were estimated by grating interferometry and X-ray radiography. In addition, the influence of X-ray glitches on the focusing properties of the compound refractive lens were studied.

30-Lens interferometer for high-energy X-rays.

A novel high-energy multi-lens interferometer consisting of 30 arrays of planar compound refractive lenses is reported. Under coherent illumination each lens array creates a diffraction-limited secondary source. Overlapping such coherent beams produces an interference pattern demonstrating strong longitudinal functional dependence. The proposed multi-lens interferometer was tested experimentally at the 100 m-long ID11 ESRF beamline in the X-ray energy range from 30 to 65 keV. The interference pattern generated by the interferometer was recorded at fundamental and fractional Talbot distances. An effective source size (FWHM) of the order of 15 µm was determined from the first Talbot image, proving the concept that the multi-lens interferometer can be used as a high-resolution tool for beam diagnostics.

Loss of Rad51c accelerates tumourigenesis in sebaceous glands of Trp53-mutant mice.

Germline mutations in RAD51C predispose to breast and ovarian cancers. However, the mechanism of RAD51C-mediated carcinogenesis is poorly understood. We previously reported a first-generation Rad51c-knock-out mouse model, in which a spontaneous loss of both Rad51c and Trp53 together resulted in a high incidence of sebaceous carcinomas, particularly in preputial glands. Here we describe a second-generation mouse model, in which Rad51c is deleted, alone or together with Trp53, in sebaceous glands, using Cre-mediated recombination. We demonstrate that deletion of Rad51c alone is not sufficient to drive tumourigenesis and may only cause keratinization of preputial sebocytes. However, deletion of Rad51c together with Trp53 leads to tumour development at around 6 months of age, compared to 11 months for single Trp53-mutant mice. Preputial glands of double-mutant mice are also characterized by increased levels of cell proliferation and DNA damage and form multiple hyperplasias, detectable as early as 2 months of age. Our results reveal a critical synergy between Rad51c and Trp53 in tumour progression and provide a predictable in vivo model system for studying mechanisms of Rad51c-mediated carcinogenesis.

Prolonged dry apnoea: effects on brain activity and physiological functions in breath-hold divers and non-divers.

PURPOSE: The aim of the study was to investigate the effects of voluntary breath-holding on brain activity and physiological functions. We hypothesised that prolonged apnoea would trigger cerebral hypoxia, resulting in a decrease of brain performance; and the apnoea's effects would be more pronounced in breath-hold divers. METHODS: Trained breath-hold divers and non-divers performed maximal dry breath-holdings. Lung volume, alveolar partial pressures of O2 and CO2, attention and anxiety levels were estimated. Heart rate, blood pressure, arterial blood oxygenation, brain tissue oxygenation, EEG, and DC potential were monitored continuously during breath-holding. RESULTS: There were a few significant changes in electrical brain activity caused by prolonged apnoea. Brain tissue oxygenation index and DC potential were relatively stable up to the end of the apnoea in breath-hold divers and non-divers. We also did not observe any decrease of attention level or speed of processing immediately after breath-holding. Interestingly, trained breath-hold divers had some peculiarities in EEG activity at resting state (before any breath-holding): non-spindled, sharpened alpha rhythm; slowed-down alpha with the frequency nearer to the theta band; and untypical spatial pattern of alpha activity. CONCLUSION: Our findings contradicted the primary hypothesis. Apnoea up to 5 min does not lead to notable cerebral hypoxia or a decrease of brain performance in either breath-hold divers or non-divers. It seems to be the result of the compensatory mechanisms similar to the diving response aimed at centralising blood circulation and reducing peripheral O2 uptake. Adaptive changes during apnoea are much more prominent in trained breath-hold divers.

pHLIP peptide targets nanogold particles to tumors.

Progress in nanomedicine depends on the development of nanomaterials and targeted delivery methods. In this work, we describe a method for the preferential targeting of gold nanoparticles to a tumor in a mouse model. The method is based on the use of the pH Low Insertion Peptide (pHLIP), which targets various imaging agents to acidic tumors. We compare tumor targeting by nonfunctionalized nanogold particles with nanogold-pHLIP conjugates, where nanogold is covalently attached to the N terminus of pHLIP. Our most important finding is that both intratumoral and i.v. administration demonstrated a significant enhancement of tumor uptake of gold nanoparticles conjugated with pHLIP. Statistically significant reduction of gold accumulation was observed in acidic tumors and kidney when pH-insensitive K-pHLIP was used as a vehicle, suggesting an important role of pH in the pHLIP-mediated targeting of gold nanoparticles. The pHLIP technology can substantially improve the delivery of gold nanoparticles to tumors by providing specificity of targeting, enhancing local concentration in tumors, and distributing nanoparticles throughout the entire tumor mass where they remain for an extended period (several days), which is beneficial for radiation oncology and imaging.

Large-acceptance diamond planar refractive lenses manufactured by laser cutting.

For the first time, single-crystal diamond planar refractive lenses have been fabricated by laser micromachining in 300 µm-thick diamond plates which were grown by chemical vapour deposition. Linear lenses with apertures up to 1 mm and parabola apex radii up to 500 µm were manufactured and tested at the ESRF ID06 beamline. The large acceptance of these lenses allows them to be used as beam-conditioning elements. Owing to the unsurpassed thermal properties of single-crystal diamond, these lenses should be suitable to withstand the extreme flux densities expected at the planned fourth-generation X-ray sources.

High prevalence of GPRC5A germline mutations in BRCA1-mutant breast cancer patients.

In a search for new breast cancer (BC) predisposing genes, we performed a whole exome sequencing analysis using six patient samples of familial BC and identified a germline inactivating mutation c.183delG [p. Arg61fs] in an orphan G protein-coupled receptor GPRC5A. An extended case-control study revealed a tenfold enrichment for this mutation in BC patients carrying the 5382insC allele of BRCA1, the major founder mutation in the Russian population, compared to wild-type BRCA1 BC cases [6/117 (5.1%) vs. 8/1578 (0.5%), p = 0.0002]. In mammary tumors (n = 60), the mRNA expression of GPRC5A significantly correlated with that of BRCA1 (p = 0.00018). In addition, the amount of GPRC5A transcript was significantly lower in BC obtained from BRCA1 mutation carriers (n = 17) compared to noncarriers (n = 93) (p = 0.026). Accordingly, a siRNA-mediated knockdown of either BRCA1 or GPRC5A in the MDA-MB-231 human BC cell line reduced expression of GPRC5A or BRCA1, respectively. Knockdown of GPRC5A also attenuated radiation-induced BRCA1- and RAD51-containing nuclear DNA repair foci. Taken together, these data suggest that GPRC5A is a modifier of BC risk in BRCA1 mutation carriers and reveals a functional interaction of these genes.

Impact of distance-based metric learning on classification and visualization model performance and structure-activity landscapes.

This study concerns large margin nearest neighbors classifier and its multi-metric extension as the efficient approaches for metric learning which aimed to learn an appropriate distance/similarity function for considered case studies. In recent years, many studies in data mining and pattern recognition have demonstrated that a learned metric can significantly improve the performance in classification, clustering and retrieval tasks. The paper describes application of the metric learning approach to in silico assessment of chemical liabilities. Chemical liabilities, such as adverse effects and toxicity, play a significant role in drug discovery process, in silico assessment of chemical liabilities is an important step aimed to reduce costs and animal testing by complementing or replacing in vitro and in vivo experiments. Here, to our knowledge for the first time, a distance-based metric learning procedures have been applied for in silico assessment of chemical liabilities, the impact of metric learning on structure-activity landscapes and predictive performance of developed models has been analyzed, the learned metric was used in support vector machines. The metric learning results have been illustrated using linear and non-linear data visualization techniques in order to indicate how the change of metrics affected nearest neighbors relations and descriptor space.

Photo- and X-ray Induced Cytotoxicity of CeF3-YF3-TbF3 Nanoparticle-Polyvinylpyrrolidone-"Radachlorin" Composites for Combined Photodynamic Therapy.

The Ce0.5Y0.35Tb0.15F3 nanoparticles with a CeF3 hexagonal structure were synthesized using the co-precipitation technique. The average nanoparticle diameter was 14 ± 1 nm. The luminescence decay curves of the Ce0.5Y0.35Tb0.15F3 nanoparticles (λem = 541 nm, 5D4-7F5 transition of Tb3+) conjugated with Radachlorin using polyvinylpyrrolidone coating as well as without Radachlorin were detected. Efficient nonradiative energy transfer from Tb3+ to the Radachlorin was demonstrated. The maximum energy transfer coefficients for the nanoparticles conjugated with Radachlorin via polyvinylpyrrolidone and without the coating were 82% and 55%, respectively. The average distance between the nanoparticle surface and Radachlorin was R0 = 4.5 nm. The best results for X-ray-induced cytotoxicity were observed for the NP-PVP-Rch sample at the lowest Rch concentration. In particular, after X-ray irradiation, the survival of A549 human lung carcinoma cells decreased by ~12%.

A comprehensive functional characterization of BRCA2 variants associated with Fanconi anemia using mouse ES cell-based assay.

Biallelic mutations in the human breast cancer susceptibility gene, BRCA2, are associated with Fanconi anemia, implying that some persons who inherit 2 deleterious variants of BRCA2 are able to survive even though it is well established that BRCA2 is indispensable for viability in mice. One such variant, IVS7 + 2T > G, results in premature protein truncation because of skipping of exon 7. Surprisingly, the persons who are either IVS7 + 2T > G homozygous or compound heterozygous are born alive but die of malignancy associated with Fanconi anemia. Using a mouse embryonic stem cell-based functional assay, we found that the IVS7 + 2T > G allele produces an alternatively spliced transcript lacking exons 4-7, encoding an in-frame BRCA2 protein with an internal deletion of 105 amino acids (BRCA2(Δ105)). We demonstrate that BRCA2(Δ105) is proficient in homologous recombination-mediated DNA repair as measured by different functional assays. Evaluation of this transcript in normal and leukemia cells suggests that BRCA2(Δ105) may contribute to the viability of persons inheriting this mutation. In this study, we have also characterized 5 other BRCA2 variants and found 3 of these (p.L2510P, p.R2336H, and p.W2626C) to be deleterious and 2 (p.I2490T and p.K2729N) probably neutral. Such studies are important to understand the functional significance of unclassified BRCA2 variants.

Case report: Sagliker syndrome in the patient with recurrent tertiary hyperparathyroidism due to intrathyroidal parathyroid carcinoma.

Sagliker syndrome (SS) is an extremely rare disorder that manifests in patients with advanced chronic kidney disease (CKD) undergoing programmed hemodialysis as a renal replacement therapy. Treatment of secondary hyperparathyroidism (SHPT) in these patients is still challenging. The main clinical manifestations of SS include craniofacial and fingertip deformities, dental anomalies, gingival hyperplasia, short stature, hearing loss, neurological and psychiatric impairment. The etiology and pathogenesis of SS in patients with SHPT require further clarification. However, mutations in the GNAS1, FGF23, and FGFR3 genes were described in some patients, suggesting a possible role of genetic predisposition to the syndrome. The preferred therapeutic approach for SS is surgery, but the volume of the operation is debated. The main surgical strategies include total, subtotal parathyroidectomy, or total parathyroidectomy with autotransplantation of the parathyroid gland (PG). Unfortunately, parathyroidectomy does not contribute to the regression of significant skeletal deformities. We present a unique clinical case of a patient with classical features of SS, recurrent tertiary hyperparathyroidism (THPT) after total parathyroidectomy due to intrathyroidal parathyroid carcinoma (PC).