Ovarian cancer (OvCa) is the most lethal gynecologic malignancy owing to its high chemoresistance and late diagnosis, which lead to a poor prognosis. Hence, developing new therapeutic modalities is important for OvCa patient treatment. Our previous results indicated that a novel aptamer, Tx-01, can specifically recognize serous carcinoma cells and tissues. Here, we aim to clarify the clinical role and possible molecular mechanisms of Tx-01 in OvCa. Immunostaining and statistical analysis were performed to detect the interaction of Tx-01 and heat shock protein 70/Notch1 intracellular domain (HSP70/NICD) in OvCa. The in vitro and in vivo experiments were carried out to demonstrate the potential mechanisms of Tx-01. Results show that Tx-01 reduced serous OvCa OVCAR3 cell migration and invasion and inhibited HSP70 nuclear translocation by interrupting the intracellular HSP70/NICD interaction. Furthermore, Tx-01 suppressed serous-type OVCAR3 cell tumor growth in vivo. Tx-01 acts as a prognostic factor through its interaction with membrane-bound HSP70 (mHSP70 that locates on the cell surface without direct interaction to NICD) on ascitic circulating tumor cells (CTCs) and is reported to be involved in natural killer (NK) cell recognition and activation. Our data demonstrated that Tx-01 interacted with HSP70 and showed therapeutic and prognostic effects in serous OvCa. Tx-01 might be a potential inhibitor for use in serous OvCa treatment.
© 2021 The Authors.

One of the tasks of current oncology is identification of cancer stem cells and search of therapeutic means capable of their specific inhibition. The paper presents the data on phenotype characteristics of Ehrlich carcinoma cells as convenient and easy-to-follow model of tumor growth. The evidence of cancer stem cells as a part of Ehrlich carcinoma and significance of CD44+ and CD44- subpopulations in maintaining the growth of this type of tumor were demonstrated. A high (tenfold) tumorigenic activity of the Ehrlich carcinoma CD44+ cells if compared to CD44- cells was proven. In this pair of comparison, the CD44+ cells had a higher potential of generating in peritoneal cavity of CD44high, CD44+CD24-, CD44+CD24+ cell subpopulations, highlighting the presence of cancer stem cells in a pool of CD44+ cells.In this study, the ability of synthesized hybrid nanocomplexes, comprising the nanoparticles of rare earth orthovanadates GdYVO4:Eu3+ and cholesterol to inhibit the tumor growth and to increase the survival of the animals with tumors was established. A special contribution into tumor-inhibiting effect is made by each of its components. Treatment of Ehrlich carcinoma cells with two-component hybrid complex resulted in maximum reduction in the concentration of the most tumorigenic CD44high cells with simultaneous rise in the number of CD117+ cells that decreased an intensity of tumor growth by 74.70 ± 4.38% if compared with the control.