Expression of somatostatin receptor subtypes and growth inhibition in human exocrine pancreatic cancers
Abstract
The antiproliferative effects of somatostatin and its analogs on human pancreatic cancers were studied:
(1) by evaluating the gene expression of somatostatin receptor (sstr) subtypes in human pancreatic cancer cell lines and cancer tissue specimens;
(2) by evaluating the antiproliferative effects of somatostatin analogs;
(3) by evaluating the effect of sstr-2 cDNA transduction.
Using a reverse transcriptase polymerase chain reaction (RT-PCR), the gene expression of five sstr subtypes (sstr-1 to -5) was examined in eight cell lines, and in ten pancreatic cancer tissues and in the normal surrounding pancreatic tissues.
The antiproliferative effects of somatostatin (SS) -14 and its two analogs (SMS 201-995, RC-160) were examined by means of an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (thiazolyl blue)) assay on three cell lines and Panc-1 transfectants with human sstr (hsstr)-2A cDNA.
Sstr-2 was expressed in all samples tested.
All examined cell lines simultaneously expressed sstr-2 and -5, while most of the examined pancreatic cancer tissues did not express both of these subtypes simultaneously.
Somatostatin analogs inhibited epidermal growth factor (EGF)-stimulated pancreatic cancer cell proliferation.
The cell proliferation was further and significantly inhibited by 14% in stable transfectants of Panc-1 cells with hsstr-2A.
Based on these findings, it is concluded that somatostatin analogs with their antiproliferative effects mediated by sstr-2 could be potentially useful in the treatment of pancreatic cancers.
See also:
- Somatostatin in oncology, the overlooked evidences;
- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;