Targeted cytotoxic somatostatin analog AN-162 inhibits growth of human colon carcinomas and increases sensitivity of doxorubicin resistant murine leukemia cells.

The effect of the targeted cytotoxic somatostatin (SST) analog AN-162, consisting of doxorubicin (DOX) conjugated to SST carrier RC-121, was investigated on the growth of human colorectal cancer (CRC) cell lines HT-29, HCT-15, and HCT-116 and a DOX-resistant mouse leukemia cell line P388/R84. mRNA for SST-receptors and high affinity binding sites for SST were detected in all CRC cell lines and in P388/R84 cells. In contrast to DOX alone, AN-162 blocked HCT-116 cells and P388/R84 cells in S/G2 phase and increased the number of apoptotic cells. In vivo, AN-162 reduced the volume of CRC xenografts more effectively than its unconjugated components. Our results suggest that AN-162 inhibits growth of experimental CRC more effectively than DOX and increases sensitivity of DOX resistant human leukemia cells.