STIP1 Involved In P2X₇ Receptor Mediated Lymphatic Metastasis Of Murine Lymphoma Cells

Lymphomas is a heterogeneous group of malignancies, it derived from lymph nodes and lymphoid tissue. Lymphomas is one of the earliest discovered hematological tumor. According to WHO(World Health Organization) classification, which carried out in 2001 and revised in 2008, Lymphomas is classify into two categories, HL(Hodgkin lymphoma) and NHL(Non-Hodgkin lymphoma).In China, NHL is the most common lymphoma, approximately about 90% of all lymphomas. The efficiency of lymphoma diagnosis is low, the therapies of lymphomas are less and can cause a lot of side effects, and these factors bring patients various troubles. P2X7 R is an ATP-gated cation channel expressed on the cytomembrane. When activated by ATP, the channel is opened and allowing Na+, K+, Ca2+ or other large hydrophilic molecules to pass through. P2X7 R is expressed on tumor cells and normal cells, and participates in cell proliferation and apoptosis. In our early research, inhibiting the expression of P2X7 R in murine lymphoma cell line P388D1, could significantly decrease the ability that metastasize to peripheral lymph nodes. STIP1 contains three TPR(tetratricopeptide repeat) domains which are structure base of the biological function. STIP1 can interact with Hsp70 and Hsp90 and form a complex, which is important for diverse processes include RNA splicing, protein folding and functional protein synthesis. STIP1 has been reported to express in not only normal cells but also tumor cells, and promote tumor progression. Objects: in order to further know the probable mechanism of P2X7 R induced lymphoma metastasis, in early experiments, we silenced the expression of P2X7 R in P388D1 cell, and constructed a mouse lymphatic metastasis model. The lymphoma cell metastasized to peripheral lymph nodes, we analyzed the protein in the metastatic lymph nodes by proteomics technique, and found that when P2X7 R expression was inhibited, the expression of STIP1 was also decreased. In order to know whether STIP1 participated in the metastatic process, we decreased the expression of STIP1 in murine lymphoma cells and to study the function of STIP1 in the lymphatic metastasis of lymphoma.Methods: first, detecting the expression of P2X7 R and STIP1 in murine lymphoma cell lines P388D1 and L1210 by RT-PCR and Western Blot. Second, infecting P388D1 and L1210 by STIP1 shRNA lentivirus, checking the infection efficiency, and verifying the inhibition of P2X7 R and STIP1 in P388D1 and L1210 by RT-PCR and Western Blot. Lastly, injecting the cells into mice footpads to construct mouse lymphatic metastasis model, research the function of STIP1 in lymphoma metastasis.Results: P2X7 R and STIP1 were expressed in P388D1 and L1210. STIP1 shRNA lentivirus could inhibit the expression of P2X7 R and STIP1 in P388D1 and L1210. Compared with non-treat cells, the cells infected by STIP1 shRNA lentivirus showed a markedly lower ability of metastasizing to peripheral lymph nodes and could increase the survival time of mice.Conclusion: deceasing the expression of STIP1 can significantly inhibit the metastatic ability of lymphoma cells, STIP1 involved in lymphoma lymphatic metastasis process.