910 ISSN 0026-8933, Molecular Biology, 2021, Vol. 55, No. 6, pp. 910–918. © Pleiades Publishing, Inc., 2021. Russian Text © The Author(s), 2021, published in Molekulyarnaya Biologiya, 2021, Vol. 55, No. 6, pp. 1011–1020. Serum of Mice Immunized with MT1-MMP Metalloproteinase Reduces Migration Potential of Pancreatic Cancer Cells N. A. Mitkin a, *, A. S. Ustiugova a , A. N. Uvarova a , K. A. Rumyantsev b , K. V. Korneev a , and V. V. Pavshintsev c a Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia b Moscow Clinical Scientific Center, Moscow, 111123 Russia c Institute of Mitoengineering MSU, Moscow, 119192 Russia *e-mail: mitkin.n.a@gmail.com Received March 18, 2021; revised May 5, 2021; accepted May 13, 2021 Abstract—Expression levels of matrix metalloproteinases, in particular MT1-MMP, are elevated in pancre- atic cancer (PC) cells, and this is associated with increased tumor proliferation, invasion, and migration. MT1-MMP is considered a promising target for drug therapy of PC, but the use of inhibitors and therapeutic antibodies to MT1-MMP is limited because maximal efficiency is only observed in a narrow time interval, at the early asymptomatic stages of the disease. This problem could be solved by immunization to MPs at the moment of detection of the primary tumor. This therapeutic effect could be provided by specific antibodies that can be re-produced in case of relapses. Here, we selected the optimal mode for immunization of mice with MT1-MMP fragments that allows us to obtain a high titer of specific antibodies in the blood serum. The obtained antiserums effectively inhibited MT1-MMP enzymatic activity, migration of PANC-02 PC cells through the collagen matrix, and activation of the main inducers of epithelial-mesenchymal transition, TGF-β and MMP-2. These results may be useful in the development of drugs for PC treatment, and the approach we propose might form the basis for design of antitumor drugs with prolonged action. Keywords: matrix metalloproteinases, MT1-MMP, peptides, immunization, anti-serum, pancreatic cancer, TGF-β, epithelial-mesenchymal transition, mice, PANC-02 DOI: 10.1134/S0026893321050095 Pancreatic cancer (PC) is an aggressive malignant neoplasm, the average survival time of patients after diagnosis is 4–6 months, and the 5-year survival rate is only 5–7% [1]. This is largely due to the fact that the early stages of the disease are asymptomatic, which complicates the timely diagnosis of PC, the tumor is treated surgically in only 20% of patients with newly diagnosed PC [2], and surgery is the most effective method of therapy, since the effectiveness of radio and chemotherapy for this type of cancer is extremely low. Thus, the survival rate of patients who undergo a course of chemotherapy with the new generation drug gemcitabine, approved for the treatment of progres- sive PC [3], averages 6 months [1]. It should be noted that 85% of successfully operated patients develop relapses within 3 years, which reduces the survival rate of patients with PC. [4]. With adjuvant chemotherapy (using S-1 or gemcitabine), the proportion of patients who experience tumor recurrence decreases, but still remains extremely high – about 70% over 3-years [5, 6]. Diagnosis of local relapses, when their removal is still possible is critical. Unfortunately, the tomography methods that are used are not always able to detect a tumor that has arisen in previously operated tissue [2]. Thus, at the moment, much attention is paid to the search for therapeutic approaches that can slow down the growth of a recurrent tumor and localize it, thereby preserving it at the time of detection in a state that is susceptible to surgical treatment. For this, matrix metalloproteinases (MMP) are considered promising targets [7]. It is known that the expression of a number of metalloproteinases (MMP-1, MMP-2, MMP-7, MMP-9, MT1-MMP, MT2-MMP, MT3-MMP) is increased in PC cells [8], and MMP-2, MMP-7, and MMP-9, are detected in the blood of patients with PC, which are proposed to be used as diagnostic markers [9]. The main effect of MMP in tumor pro- gression is due to proteolysis of collagen, a key compo- nent of the extracellular matrix, which promotes tumor invasion and angiogenesis. [10]. Proteolytic activity of a number of MMPs is involved in the regu- lation of the activity of factors that induce oncogene- sis. Thus, MMP-2 and MT1-MMP activate TGF-β, which, in turn, induces epithelial-mesenchymal transi- tion (EMF) [11, 12]. It has been shown that MT1-MMP is involved in the processing of TGF-β-binding pro- tein 1 (LTBP-1), thereby inducing the release of latent TGF-β and subsequent activation of Snail family pro- MOLECULAR CELL BIOLOGY UDC 577.27