| Purpose: Multiple myeloma is a common hematological malignancy, accountsfor2%of the total cancer mortality. Therefore, it is urgent to look for a novel methodto improve the therapeutic efficacy of MM. Cancer immunotherapy came into thepublic eye recently, owing to the significance of its therapeutic effect. Adoptivecellular immunotherapy is a rapidly developing treatment among them, whosecurative efficacy is obvious in the treatment of many tumors. The combination of ACIand conventional MM treatments may improve the healing of MM, which is a subjectworthy of studying. This experiment selects arsenic trioxide and bortezomib, twocommon MM chemotherapy drug, to identify whether low dose drug can increase theimmunogenisity of MM cell line RPMI-8226, and to observe the sensitization tonatural killer (NK) cells and gamma delta (γ) T cells-mediated cytotoxicity, to try toexplore the underlying mechanism, and to provide new ideas for clinial therapy.Methods: Mononuclear cells in peripheral blood from10MM patients werestimulated by corresponding cytokines to induce NK and γ T cells; The expression ofCD3, CD56, NKG2D and DNAM-1on NK cells, the expression of CD3、Vγ9、NKG2D and DNAM-1on γ T cells, as well as the alteration of MICA、MICB andCD155expression on RPMI-8226cellular surface before and after ATO and Borpretreatment were detected by flow cytometry;The inhibition of ATO and Bor onRPMI-8226, NK and γ T cells proliferation were detected by MTT assay;The cellularkilling effects of NK and γ T cells on ATO and Bor pretreated cell line were detectedby calcein release assay.Results:1. Induced NK and γ T cells, had a very high purity (85.76±6.28)%and (92.30±3.47), respectively.2. ATO and Bor inhibit RPMI-8226cell proliferation, in a dose-dependent manner.3. Low dose ATO can increase the expression of NKG2Dligand, MICA and MICB on RPMI-8226cell surface in a time-dependent manner.However, low dose Bor can increase the expression of NKG2D ligand, MICA andMICB on RPMI-8226cell surface transiently, with a peak appearing around8h. ATOand Bor also increase the expression of DNAM-1ligand, CD155on RPMI-8226cellular surface.4. Low dose ATO and Bor can both inhibit γ T and NK cellproliferation in vitro.The cellular proliferation inhibition of ATO is stronger on γ Tcells than on RPMI-8226cells, interestingly.5. The cellular killing effect of NK andγ T cells on RPMI-8226cells pretreated with low-dose ATO and Bor is significantlystronger than the same cells without pretreatment.6. The cellular killing effect of NKcells on drug pretreated RPMI-8226cells decrease obviously by blocking NKG2Dseperately, however it is still stronger than that on unpretreated MM cells. The cellularkilling effect of NK cells decrease obviously both on drug pretreated RPMI-8226cellsand on unpretreated ones by either only blocking DNAM-1or both blockingDNAM-1and NKG2D at the same time, while there was no significant differencesbetween these two groups.7. The cellular killing effect of γ T cells on drug pretreatedRPMI-8226cells decrease obviously either by blocking DNAM-1or NKG2Dseperately or both at the same time, which is still stronger than that on unpretreatedcells.Conclusion:1. NK and γ T cells were successfully induced with a high purityand an obvious cellular killing effect on RPMI-8226cells.2. Both ATO and Bor werecellular proliferating inhibitory on NK, γ T and RPMI-8226cells.ATO had thestrongest inhibition on γ T cells, followed by NK cells and RPMI-8226cells. WhileBor had the strongest inhibitory effect on RPMI-8226cell.3. Low-dose ATO or Borcould sensitization RPMI-8226cells to NK cells lysis, by up-regulation of MICA,MICB and CD155on MM cells, therefore depend on the DNAM-1and NKG2Dpathway and mainly on NKG2D pathway.4. Low-dose ATO or Bor couldsensitization RPMI-8226cells to γ T cells lysis, partly by up-regulation of cellularsurface receptors MICA, MICB and CD155, therefore depend on the DNAM-1and NKG2D pathway. |
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