Y reduced pGL3 1416/ 219 luciferase reporter activity. To examine the prospective involvement of PKC in controlling its personal promoter activity, we utilised PKC RNAi. PKC expression was silenced from MCF-7 cells by 90 upon delivery of two various PKC RNAi duplexes ( 1 and 2), as we did previously in other models (18, 25). Notably, luciferase activity of the pGL3 1416/ 219 reporter was significantly decreased in PKC -depleted MCF-7 cells (Fig. 8D), indicating that the elevated levels of PKC in breast cancer cells positively control its personal expression at a transcriptional level. The outcomes described above argue for any mutual dependence among PKC expresJOURNAL OF BIOLOGICAL CHEMISTRY1 St -2 d AP -AB+ ++ + 10 SpFree probeTranscriptional Regulation of PKC in Cancer CellsN TC N TC N TC N TC N TC # 1 # two # 1 # 2 # 1 # 2 # 1 # 2 # 1 #1 2 #ARNAip-STAT1 (GSK-3β Inhibitor custom synthesis Ser727) STAT1 PKC -actin MCF-VT-47DMDA-MB-MDA-MB-MDA-MB-BG F C tlC50 40 30 20 10CDNT C #RNAi PKC-p-STAT1 (Ser727)Luciferase activity ( )1.0 p-STAT1 (Ser 727) level0.Luciferase activity ( )VinculinVinculinG F tl -V 1 N TC # 1 # two tl -C VE7D BT -4 74 H C C M -14 D 19 A M -MB D A- -23 M 1 M BD A- 453 M B46 8 ten AFPKC levelsFC M MCTF-PKC p-STAT1 (Ser727) -actin2 R =0.0 0 50FIGURE 8. Correlation in between PKC expression levels and STAT1 activation status. A, PKC RNAi depletion reduces phospho-Ser-727-STAT1 levels in breast cancer cell lines. MCF-7, T-47D, MDA-MB-231, MDA-MB-453, and MDA-MB-468 cells were transiently transfected with PKC (1 or 2) or nontarget control (NTC) RNAi duplexes. After 72 h, levels of phospho-Ser-727-STAT1 and total STAT1 had been determined by Western blot. A second experiment gave equivalent results. B, effect of pan-PKC inhibitor GF109203X (five M, 24 h) or the PKC inhibitor V1-2 (1 M, 24 h) on phospho-Ser-727-STAT1 levels in MCF-7 cells, as determined by Western blot (upper panel). A representative experiment is shown, collectively with densitometric analysis. Information are expressed as imply S.E. of four person experiments. , p 0.05, , p 0.01 versus control. C, inhibition of pGL3 1416/ 219 reporter activity in MCF-7 cells by V1-2 (1 M, 24 h). Luciferase activity of construct pGL3 1416/ 219 was determined 48 h just after transfection. Information are expressed as mean S.D. of triplicate samples. Two extra experiments gave same results. , p 0.05 versus manage. D, inhibition of pGL3 1416/ 219 reporter activity by PKC RNAi. MCF-7 cells had been transiently transfected with PKC (1 or two) or nontarget control RNAi duplexes. Immediately after 24 h, pGL3 1416/ 219 was transiently transfected into MCF-7 cells in conjunction with the pRL-TK Renilla luciferase vector. Luciferase activity was determined 48 h later. Information are expressed as imply S.D. of triplicate samples. Two additional experiments gave exact same final results. , p 0.05 versus handle. Inset, PKC expression, as determined by Western blot. E, PKC and phospho-Ser-727-STAT1 levels in mammary cell lines, as determined by Western blot. Related results were observed in 3 independent experiments. F, correlation involving expression levels of PKC and phosphoSer-727-STAT1 levels in mammary cell lines.sion and STAT1 activation. We decided to formally test this hypothesis in mammary cellular models (Fig. 8E). We observed that normal immortalized MCF-10A cells, which express low PKC levels, show low levels of phospho-Ser-727-STAT1. Conversely, breast cancer cell lines with very higher PKC levels (MCF-7, T-47D, MDA-MB-231, MDA-MB-453, and IL-12 Activator custom synthesis MDAMB-468) show higher levels of phospho-Ser-727-STAT1. B.