Search

The sodium-dependent phosphate cotransporter NaPi2b encoded by the SLC34A2 gene is a transmembrane protein that belongs to the family of phosphate transporters SLC34 and is involved in maintaining phosphate homeostasis in the human body. The phosphate transporter NaPi2b is expressed in several normal tissues and body organs, as well as in malignant neoplasms of the ovary, lung, colorectal, and other types of cancer. The membrane protein NaPi2b is a target for therapeutic humanized antibodies Rebmab200, XMT-1535, and XMT-1536 in cancer cells. These antibodies were created based on MX35 antibodies and are directed against the large extracellular domain of the transporter NaPi2b. Since the location of the N-terminal domain of NaPi2b in the cell has not been experimentally confirmed, this work aimed to analyze the recognition of the phosphate transporter NaPi2b in ovarian cancer cells OVCAR-4 and OVCAR-8 by antibodies against the N-terminal domain of the transporter using Western blot analysis and confocal microscopy.

The high mortality rate from ovarian cancer is due to the asymptomatic nature of the course of the disease, which leads to the diagnosis of ovarian cancer in later stages. The sodium-dependent phosphate transporter NaPi2b encoded by SLC34A2 gene is expressed in 80–90% of epithelial ovarian cancers and used as a target for therapeutic antibodies XMT-1536, and XMT-1592, which are derived from MX35 antibodies and used in clinical trials for the treatment of ovarian and lung cancers. In this work, we aimed to evaluate NaPi2b as a molecular marker for diagnostics and predicting the course and outcome of ovarian cancer disease.Quantitative analysis of SLC34A2 gene expression in ovarian tumor tissue was performed at the level of transcription and translation using real-time PCR, droplet digital PCR and Western blot analysis respectively. Statistical analysis was performed taking into account various clinicopathological characteristics of the ovarian cancer patients, including the stage of the disease, the tumor grade, the applying of neoadjuvant chemotherapy and the presence of ascites. In this work, we demonstrated that the expression of the human NaPi2b (hNaPi2b) transporter is downregulated in the tumors of patients receiving neoadjuvant therapy and during the development of disease. The data suggest that the level of expression of the SLC34A2 gene can serve as a potential marker for the monitoring and predicting responses to neoadjuvant and targeted therapy in patients with ovarian cancer.

Pancreatic cancer is one of the most painful and aggressive types of cancer with high lethality rate. Early diagnosis of the disease is limited and antitumor therapy has low efficacy, because pancreatic cancer shows multiple drug resistance. It is still unclear how pancreatic tumor cells become resistant to chemotherapy and understanding of the resistance mechanisms and identification of their regulating genes is necessary to develop a new and more efficient pancreatic cancer therapy. One of the methods to identify such genes is CRISPR/Cas9 technology (clustered regularly interspaced short palindromic repeats) where Cas9 endonuclease is used to make double-strand DNA breaks in target genes. The aim of this work is modification of the pancreatic cancer cell line MIA PaCa-2 to express a doxycycline-inducible Cas9 endonuclease gene. Several plasmid vectors have been used to create a lentivirus containing the Cas9 endonuclease gene. The virus has been used for transduction of tumor cells to get doxycycline-inducible Cas9 expressing clones. Cas9 endonuclease expression has been detected by the western blot analysis with antibodies to FLAG epitope. Two tumor clones of the MIA Pa-Ca2/Cas9 cell line expressing Cas9 endonuclease have been generated. These cells can be used further to search genes related to regulation of the susceptibility to antitumor drugs.