| Popis: |
A) Breast cancer BT-474, SKBR3, JIMT-1, and MDA-MB-436 cells, B) ovarian cancer OVCAR3, SKOV3, CaOV3, and HEY cells, and C) gastric N87, MKN-28, MKN-45 and esophageal cancer OE19 cells were treated with commercial or virus-produced trastuzumab (N87 cell line) in escalating doses (left panels), or infected with indicated viruses at increasing virus particle per cell (VP/cell) titers (right panels). Three HER2-positive (HER2+) cancer cell lines, BT-474, N87 and OE19, showed dose-dependent susceptibility to anti-HER2 antibody treatment with IC50-value at 80.3 ng/mL, 196.3 ng/mL, and 239.1 ng/mL on day 6 post-treatment, respectively. Equivalent doses of virus-produced trastuzumab purified from supernatant of Ad5/3-Î"24-tras infected 293 cells resulted in comparable cytotoxicity of HER2-positive N87 gastric cancer (C, top left, dashed line: data from identical separate experiment). Trastuzumab-coding virus Ad5/3-Î"24-tras and the oncolytic control virus Ad5/3-Î"24 showed significant cytotoxicity in all tested cancer cell lines (right panels, A-C), while non-replicating control viruses lacked efficacy. Potency of Ad5/3-Î"24-tras virus in vitro was pronounced in cell lines expressing HER2 (comparable to oncolytic control virus in BT-474, SKBR3, OVCAR3 and N87), while HER2-negative MDA-MB-436 cells were also found equally susceptible to oncolytic viruses. Importantly, both oncolytic viruses were able to mediate total cytotoxicity at the relevant 100 VP/cell titer. Of note, because Ad5/3-Î"24 lacks a transgene and its genome is therefore smaller, the virus packages more efficiently leading to a lower VP/pfu ratio (24 versus 203 in Ad5/3-Î"24-tras). Therefore cytotoxicity was also tested according to functional titers, which rendered higher potency for the recombinant Ad5/3-Î"24-tras virus (see Supplementary Fig. S2). IC50, half-maximal inhibitory concentration. |
