6th ESACP Congress, Heidelberg, April 7-11, 1999

A036
FLOW CYTOMETRIC MEASUREMENT OF APOPTOSIS FROM FRESH SOLID TISSUE OF PANCREATIC CARCINOMA XENOGRAFTS TREATED BY SANDOSTATIN (OCTREOTIDE)
Bocsi J, Zalatnai A

First Institute of Pathology and Experimental Cancer Research, Semmelweis University of Medicine, Budapest Hungary

Background: Flow cytometric DNA content measurements could be carried out on cell or nuclei suspension from fresh solid tumor tissue material. The nuclei of apoptotic cells get lower mass of DNA intercalating propidium iodid stain than nonapoptotic G1 cells because of the condensed chromatin structure and DNA loss (originated from internucleosomal fragmentation). The lower content of DNA stain of apoptotic cells resulted a so called sub G1 population on DNA histogram. Sandostatin (octreotide, a synthetic analog of somatostatin) is an approved hormone for treatment of gastro-entero-pancreatic neuroendocrine tumors, however, pancreatic adenocarcinomas have rarely been treated with this drug. Our aim was to show flow cytometrically the apoptosis-inducing effect of Sandostatin in vivo in a human pancreatic carcinoma xenograft (PZX-5). Methods: Experiments were performed on a newly established PZX-5 human pancreatic carcinoma xenograft growing in immunosuppressed mice (Int J Pancreatol., 23, 51, 1998.). Mice were treated by 500 microg/kg b.w. Sandostatin i.p. twice a day. After four weeks the tumours were processed for microscopic and flow cytometric studies. About 5-10 cubic millimeter of solid carcinoma tissue were homogenized in physiological salt solution, then cells were resuspended in 0.1 % of sodium citrate solution suplemented Results: Nine untreated and eighteen Sandostatin treated tumor samples were studied. Student t-probe verified a significant (p<0.001) growth of apoptotic ratio by Sandostatin (from 3.6+1.3% to 7.2+2.2%) among pancreatic carcinoma cells. These observations were corroborated by histologic examinations of paraffin embedded samples. Conclusions: These flow cytometric measurements were useful for showing apoptotic cells in samples prepared from fresh solid tumors. Data showed that Sandostatin inhibited the growth of pancreatic carcinoma cells in vivo, and this process could be attributed to the increased apoptotic activity. Acknowledgement: The Sandostatin used in this work was kindly given as a present by Novartis Hungary Kft. Budapest