Telomerase reverse transcriptase (TERT), a core part of telomerase, has been known for a long time only for its telomere lengthening function by reverse transcription of RNA template. Currently, TERT is considered as an intriguing link between multiple signaling pathways. The diverse intracellular localization of TERT corresponds to a wide range of functional activities. In addition to the canonical function of protecting chromosome ends, TERT by itself or as a part of the telomerase complex participates in cell stress responses, gene regulation and mitochondria functioning. Upregulation of TERT expression and increased telomerase activity in cancer and somatic cells relate to improved survival and persistence of such cells. In this review, we summarize the data for a comprehensive understanding of the role of TERT in cell death regulation, with a focus on the interaction of TERT with signaling pathways involved in cell survival and stress response.

Nowadays, the use of genetically modified NK cells is a promising strategy for cancer immunotherapy. The additional insertion of genes capable of inducing cell suicide allows for the timely elimination of the modified NK cells. Different subsets of the heterogenic NK cell population may differ in proliferative potential, in susceptibility to genetic viral transduction, and to the subsequent induction of cell death. The CD57−NKG2C+ NK cells are of special interest as potential candidates for therapeutic usage due to their high proliferative potential and certain features of adaptive NK cells. In this study, CD57− NK cell subsets differing in KIR2DL2/3 and NKG2C expression were transduced with the iCasp9 suicide gene. The highest transduction efficacy was observed in the KIR2DL2/3+NKG2C+ NK cell subset, which demonstrated an increased proliferative potential with prolonged cultivation. The increased transduction efficiency of the cell cultures was associated with the higher expression level of the HLA-DR activation marker. Among the iCasp9-transduced subsets, KIR2DL2/3+ cells had the weakest response to the apoptosis induction by the chemical inductor of dimerization (CID). Thus, KIR2DL2/3+NKG2C+ NK cells showed an increased susceptibility to the iCasp9 retroviral transduction, which was associated with higher proliferative potential and activation status. However, the complete elimination of these cells with CID is impeded.

Abstract. Active Galactic Nuclei (AGN) are considered as potential extragalactic sources of very and ultra high energy cosmic rays. According to theoretical predictions cosmic ray acceleration can take place at the shock created by the expanding cocoons around active galactic nuclei as well as at AGN jets. The measurements of AGN TeV spectra, the variability time scale of TeV emission can provide essential information on the dynamics of AGN jets, the localization of acceleration region and an estimation of its size. SHALON observations yielded data on extragalactic sources of different AGN types in the energy range of 800 GeV-100 TeV. The data from SHALON observations are compared with those from other experiments at high and very high energies.

Abstract. The radio-loud active galactic nuclei having the radio emission arising from a core region rather than from lobes are often referred to as "blazars" and include Flat Spectrum Radio Quasars (FSRQ) and BL Lacertae (BL Lac) objects. During the period 1992 -2015, SHALON has been used for observations of the metagalactic sources NGC1275, Mkn421, Mkn501, Mkn180, 3c382, 4c+31.63, OJ 287, 3c454.3, 4c+55.17, 1739+522. We present results of long term observations of FSRQ: among them are known object 3c454.3, high-red shifted quasar 1739+522 as well as BL Lac type objects. The observation results are presented with integral spectra, images and spectral energy distributions for each of sources at energies > 800 GeV. A number of variability periods in different wavelengths including VHE γ-rays were found. IntroductionHigh and very high energy γ-rays have come to play an important role in the study of Active Galactic Nuclei (AGNi). A big number of AGNi have been detected through the MeV to TeV energies. The long term SHALON observations yielded data on AGNi of different type at energy range of 800GeV -100 TeV (Table 1). The redshifts of AGNi observed by SHALON range from z=0.0179 to z=2.979. Some of these AGNi were discovered at TeV energies by SHALON. The results on fluxes, spectral energy distributions and images are shown here and [1,2,3,4,5].

The radio-loud Active Galactic Nuclei (AGNi) having the radio emission arising from a core region rather than from lobes are often referred to as "blazars" and include Flat Spectrum Radio Quasars (FSRQ) and BL Lacertae (BL Lac) objects. We present results of long term observations of FSRQ: among them are known object 3c454.3 (z= 0.859), high-red shifted quasar 1739+522 (4c+51.37) (z= 1.375) and 4c+31.63 (z= 0.295), 4c+55.17 (z= 0.896) as well as BL Lac type object OJ 287 (z= 0.306) that was recently detected by SHALON Cherenkov telescopes. Also, the observation data on known BL Lac objects Mkn 421 (z= 0.031), Mkn 501 (z= 0.034), Mkn 180 (z= 0.046) and Radio galaxies NGC 1275 (z= 0.018), 3c 382 (z= 0.0578) are summarized in this paper. The observation results are presented with integral spectra, images and spectral energy distributions for each of sources at energies above 800 GeV. A number of variability periods in different wavelengths including VHE γ-rays were found.