Monstein H J, Ohlsson B, Axelson J
Molecular Biology Laboratory, University Hospital, Linköping, Sweden.
Scand J Gastroenterol. 2001 Jul;36(7):738-43. doi: 10.1080/003655201300192003.
It has been assumed that gastrin stimulates the growth of pancreatic cancer in an autocrine way through co-expression of gastrin and the cholecystokinin-B receptor (CCK-BR). However, pancreatic cancer cell lines established directly from patients have revealed a great heterogeneity in cell proliferation when exposed to CCK, gastrin and their receptor antagonists. The aim of this study was therefore to examine co-expression of CCK-A and CCK-B receptor (CCK-AR and CCK-BR), and gastrin mRNA as well as the secretion of CCK and gastrin peptides in these cell lines.
Fourteen cell lines were established from primary pancreatic cancers or their metastases. Total RNA was isolated from the cell lines and reverse-transcribed into single-stranded cDNA. A PCR technique based on Taq polymerase-antibody interaction and CCK-AR, CCK-BR and gastrin-specific primers, followed by Southern blot analysis, were the methods used. The incubation mediums were analysed for the presence of secreted CCK/proCCK and gastrin/progastrin peptides by specific radioimmunoassays (RIA).
By means of nested Reverse-Transcribed Polymerase Chain Reaction (nested RT-PCR), combined with Southem blot analysis of the PCR amplified products, CCK-AR and gastrin mRNA co-expression was detected in cell lines LPC-6p and LPC-10m, whereas CCK-BR and gastrin mRNA could be detected in cell lines LPC-8p and LPC-12m. A low level of secreted CCK peptides was detected in cell line LPC-6p, which also expressed CCK-AR mRNA. In no other cases were CCK or gastrin peptides detected in the cell culture mediums.
The lack of CCK-BR and gastrin mRNA co-expression, and not detectable levels of secreted CCK and gastrin in culture media, does not lend support to the hypothesis that concomitant gene-expression of CCK receptors and gastrin or CCK are essential to maintaining pancreatic cancer cell proliferation.
一直以来人们认为胃泌素通过胃泌素与胆囊收缩素B受体（CCK-BR）的共表达以自分泌方式刺激胰腺癌生长。然而，直接从患者体内建立的胰腺癌细胞系在暴露于CCK、胃泌素及其受体拮抗剂时，显示出细胞增殖方面的巨大异质性。因此，本研究的目的是检测这些细胞系中CCK-A和CCK-B受体（CCK-AR和CCK-BR）、胃泌素mRNA的共表达情况，以及CCK和胃泌素肽的分泌情况。
从原发性胰腺癌或其转移灶建立了14个细胞系。从细胞系中提取总RNA并逆转录为单链cDNA。所采用的方法是基于Taq聚合酶-抗体相互作用以及CCK-AR、CCK-BR和胃泌素特异性引物的PCR技术，随后进行Southern印迹分析。通过特异性放射免疫分析（RIA）检测培养液中分泌的CCK/proCCK和胃泌素/pro胃泌素肽的存在情况。
通过巢式逆转录聚合酶链反应（巢式RT-PCR），结合对PCR扩增产物的Southern印迹分析，在细胞系LPC-6p和LPC-10m中检测到CCK-AR和胃泌素mRNA的共表达，而在细胞系LPC-8p和LPC-12m中可检测到CCK-BR和胃泌素mRNA。在也表达CCK-AR mRNA的细胞系LPC-6p中检测到低水平的分泌CCK肽。在其他情况下，未在细胞培养液中检测到CCK或胃泌素肽。
CCK-BR和胃泌素mRNA缺乏共表达，且在培养液中未检测到可分泌的CCK和胃泌素水平，这并不支持CCK受体与胃泌素或CCK的伴随基因表达对于维持胰腺癌细胞增殖至关重要这一假说。
