Shirin Farjadian; Marzie Norouzian; Vahid Younesi; Azin Ebrahimpour; Ramin Lotfi
Volume 10, Issue 2 , June 2013, , Pages 93-102
Abstract
Background: Although there is convincing data in support of the effectiveness of hyperthermia in tumor therapy, the molecular mechanisms underlying the clinical effects of hyperthermia are still poorly understood. Objective: To investigate natural killer (NK) cell cytotoxicity against heat-treated SW-872 ...
Read More
Background: Although there is convincing data in support of the effectiveness of hyperthermia in tumor therapy, the molecular mechanisms underlying the clinical effects of hyperthermia are still poorly understood. Objective: To investigate natural killer (NK) cell cytotoxicity against heat-treated SW-872 and HeLa tumor cell lines. Methods: NKG2D ligands and HLA class I transcription were examined using quantitative real-time PCR in treated tumor cell lines at 0, 2, 4, 6 and 12 h following thermal treatment at 39C and 42C for 1 h. The expression of MICA/B, ULBP1 and ULBP2 were also determined by flow cytometry. NK92-MI cytotoxic activity against heat-treated target cell lines was assessed by LDH release as well as annexin-V and 7-AAD assays. Results: Our results showed that heat treatment at 39C improved the cytolytic activity of NK cells against SW-872 cells without increasing NKG2D ligand concentration or decreasing HLA class I levels. Conclusion: The observed increase in the cytotoxicity of NK cells against SW-872 cells after hyperthermia does not coincide with changes in MICA/B, ULBP1 and ULBP2 ligands of NKG2, however, the expression of other ligands in target cells may have made the cells susceptible to the cytotoxic effect of NK cells.
Shirin Farjadian; Shahrzad Rahimifar; Nasrollah Erfani; Ramin Lotfi
Volume 10, Issue 1 , March 2013, , Pages 31-39
Abstract
Background: A possible mechanism by which hyperthermia enhances tumor immunogenicity is the induction of NKG2D ligands on tumor cells. Although the expression of MHC class I chain-related protein A and B (MICA/B) has previously been reported in different carcinomas, there is no information about MICA/B ...
Read More
Background: A possible mechanism by which hyperthermia enhances tumor immunogenicity is the induction of NKG2D ligands on tumor cells. Although the expression of MHC class I chain-related protein A and B (MICA/B) has previously been reported in different carcinomas, there is no information about MICA/B expression in liposarcomas. Objective: To investigate MICA/B induction in a human liposarcoma cell line (SW-872) after thermotherapy. Methods: SW-872 and HeLa cell lines were subjected to thermal stress for 1 h at 42, 44 and 46C, and after 2, 4 and 6 h of incubation at 37C, MICA/B expression was assessed at the mRNA and protein levels. Results: Despite high levels of MICA/B transcripts in SW-872 cells at baseline, the expression of these genes decreased significantly at both the mRNA and protein levels after almost all thermal treatments. Conclusion: Our data conclude that thermotherapy under 42-46°C had no effect on MICA/B induction on SW-872 liposarcoma cell line but the effects of fever-range temperatures remain to be tested on this cell line.