Figure 1.

Expression of human sst2 in hamster pancreatic cancer cells results in an autocrine negative loop. (A and B) PC1.0 cells stably expressing or not human sst2 receptor were cultured in 10-cm diameter dishes for 48 h in medium containing 5% FCS. Total RNA was extracted, and RT-PCR analysis was performed from clonal cell lines containing mock vector (1) or expressing human sst2 (2). The PCR products resulting from specific primers for human sst2 (A, 1107 pb), for preprosomatostatin (B, 487 pb), and β actin (A and B, 517 pb) were analyzed on polyacrylamide gels after ethidium bromide staining. M, DNA size marker (PGEM markers; Promega). RT-PCR carried out in the absence of reverse transcriptase during RT procedure were negative. Results are representative of two separate experiments. (C) Cells (4 × 10⁴ per 35-mm diameter dish) were grown in medium supplemented with 5% FCS. After 16-h attachment phase, cells were cultured in serum-free medium for 3 days. Cell growth was measured at the indicated times by cell counting. Results are expressed as the cell number per dish (mean ± SE) and are representative of two separate experiments in triplicate (□, PC-1.0 cells; ■, PC-1.0/sst2 cells; Δ, PC-1 cells; and ▴, PC-1/sst2 cells).