Browsing by Author "Latyshev, Oleg"

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    Cellular immune response induced by dna immunization of mice with drug resistant integrases of hiv-1 clade a offers partial protection against growth and metastatic activity of integrase-expressing adenocarcinoma cells
    (2021-06) Isaguliants, Maria; Krotova, Olga; Petkov, Stefan; Jansons, Juris; Bayurova, Ekaterina; Mezale, Dzeina; Fridrihsone, Ilze; Kilpelainen, Athina; Podschwadt, Philip; Agapkina, Yulia; Smirnova, Olga; Kostic, Linda; Saleem, Mina; Latyshev, Oleg; Eliseeva, Olesja; Malkova, Anastasia; Gorodnicheva, Tatiana; Wahren, Britta; Gordeychuk, Ilya; Starodubova, Elizaveta; Latanova, Anastasia; Research Department
    Therapeutic DNA-vaccination against drug-resistant HIV-1 may hinder emergence and spread of drug-resistant HIV-1, allowing for longer successful antiretroviral treatment (ART) up-to relief of ART. We designed DNA-vaccines against drug-resistant HIV-1 based on consensus clade A integrase (IN) resistant to raltegravir: IN_in_r1 (L74M/E92Q/V151I/N155H/G163R) or IN_in_r2 (E138K/G140S/Q148K) carrying D64V abrogating IN activity. INs, overexpressed in mammalian cells from synthetic genes, were assessed for stability, route of proteolytic degradation, and ability to induce oxidative stress. Both were found safe in immunotoxicity tests in mice, with no inherent carcinogenicity: their expression did not enhance tumorigenic or metastatic potential of adenocarcinoma 4T1 cells. DNA-immunization of mice with INs induced potent multicytokine T-cell response mainly against aa 209–239, and moderate IgG response cross-recognizing diverse IN variants. DNA-immunization with IN_in_r1 protected 60% of mice from challenge with 4Tlluc2 cells expressing non-mutated IN, while DNA-immunization with IN_in_r2 protected only 20% of mice, although tumor cells expressed IN matching the immunogen. Tumor size inversely correlated with IN-specific IFN-γ/IL-2 T-cell response. IN-expressing tumors displayed compromised metastatic activity restricted to lungs with reduced metastases size. Protective potential of IN immunogens relied on their immunogenicity for CD8+ T-cells, dependent on proteasomal processing and low level of oxidative stress.
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    Comparative Immunogenicity in Rabbits of the Polypeptides Encoded by the 5′ Terminus of Hepatitis C Virus RNA
    (2015) Sominskaya, Irina; Jansons, Juris; Dovbenko, Anastasija; Petrakova, Natalia; Lieknina, Ilva; Mihailova, Marija; Latyshev, Oleg; Eliseeva, Olesja; Stahovska, Irina; Akopjana, Inara; Petrovskis, Ivars; Isaguliants, Maria; Rīga Stradiņš University
    Recent studies on the primate protection from HCV infection stressed the importance of immune response against structural viral proteins. Strong immune response against nucleocapsid (core) protein was difficult to achieve, requesting further experimentation in large animals. Here, we analyzed the immunogenicity of core aa 1-173, 1-152, and 147-191 and of its main alternative reading frame product F-protein in rabbits. Core aa 147-191 was synthesized; other polypeptides were obtained by expression in E. coli. Rabbits were immunized by polypeptide primes followed by multiple boosts and screened for specific anti-protein and anti-peptide antibodies. Antibody titers to core aa 147-191 reached 105; core aa 1-152, 5 × 105; core aa 1-173 and F-protein, 106. Strong immunogenicity of the last two proteins indicated that they may compete for the induction of immune response. The C-terminally truncated core was also weakly immunogenic on the T-cell level. To enhance core-specific cellular response, we immunized rabbits with the core aa 1-152 gene forbidding F-protein formation. Repeated DNA immunization induced a weak antibody and sustained proliferative response of broad specificity confirming a gain of cellular immunogenicity. Epitopes recognized in rabbits overlapped those in HCV infection. Our data promotes the use of rabbits for the immunogenicity tests of prototype HCV vaccines.
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    DNA immunization site determines the level of gene expression and the magnitude, but not the type of the induced immune response
    (2018-06-04) Petkov, Stefan; Starodubova, Elizaveta; Latanova, Anastasia; Kilpelainen, Athina; Latyshev, Oleg; Svirskis, Simons; Wahren, Britta; Chiodi, Francesca; Gordeychuk, Ilya; Isaguliants, Maria; Rīga Stradiņš University
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    HIV-1 Reverse Transcriptase Promotes Tumor Growth and Metastasis Formation via ROS-Dependent Upregulation of Twist
    (2019-12-02) Bayurova, Ekaterina; Jansons, Juris; Skrastina, Dace; Smirnova, Olga; Mezale, Dzeina; Kostyusheva, Anastasia; Kostyushev, Dmitry; Petkov, Stefan; Podschwadt, Philip; Valuev-Elliston, Vladimir; Sasinovich, Sviataslau; Korolev, Sergey; Warholm, Per; Latanova, Anastasia; Starodubova, Elizaveta; Tukhvatulin, Amir; Latyshev, Oleg; Selimov, Renat; Metalnikov, Pavel; Komarov, Alexander; Ivanova, Olga; Gorodnicheva, Tatiana; Kochetkov, Sergey; Gottikh, Marina; Strumfa, Ilze; Ivanov, Alexander; Gordeychuk, Ilya; Isaguliants, Maria; Department of Pathology; Rīga Stradiņš University
    HIV-induced immune suppression results in the high prevalence of HIV/AIDS-associated malignancies including Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer. HIV-infected people are also at an increased risk of "non-AIDS-defining" malignancies not directly linked to immune suppression but associated with viral infections. Their incidence is increasing despite successful antiretroviral therapy. The mechanism behind this phenomenon remains unclear. Here, we obtained daughter clones of murine mammary gland adenocarcinoma 4T1luc2 cells expressing consensus reverse transcriptase of HIV-1 subtype A FSU_A strain (RT_A) with and without primary mutations of drug resistance. In in vitro tests, mutations of resistance to nucleoside inhibitors K65R/M184V reduced the polymerase, and to nonnucleoside inhibitors K103N/G190S, the RNase H activities of RT_A. Expression of these RT_A variants in 4T1luc2 cells led to increased production of the reactive oxygen species (ROS), lipid peroxidation, enhanced cell motility in the wound healing assay, and upregulation of expression of Vimentin and Twist. These properties, particularly, the expression of Twist, correlated with the levels of expression RT_A and/or the production of ROS. When implanted into syngeneic BALB/C mice, 4T1luc2 cells expressing nonmutated RT_A demonstrated enhanced rate of tumor growth and increased metastatic activity, dependent on the level of expression of RT_A and Twist. No enhancement was observed for the clones expressing mutated RT_A variants. Plausible mechanisms are discussed involving differential interactions of mutated and nonmutated RTs with its cellular partners involved in the regulation of ROS. This study establishes links between the expression of HIV-1 RT, production of ROS, induction of EMT, and enhanced propagation of RT-expressing tumor cells. Such scenario can be proposed as one of the mechanisms of HIV-induced/enhanced carcinogenesis not associated with immune suppression.