Gastroenterology

Gastroenterology

Volume 116, Issue 5, May 1999, Pages 1202-1216
Gastroenterology

Liver, Pancreas, and Biliary Tract
Bone morphogenetic protein 2 exerts diverse effects on cell growth in vitro and is expressed in human pancreatic cancer in vivo,☆☆

https://doi.org/10.1016/S0016-5085(99)70024-7Get rights and content

Abstract

Background & Aims: Bone morphogenetic proteins (BMPs) belong to the transforming growth factor β superfamily of signaling molecules. We characterized the expression of BMP-2 and its receptors in human pancreatic tissues and pancreatic cancer cell lines and examined the effects of BMP-2 on mitogenesis. Methods: Expression of BMP-2 and its receptors was determined by Northern blot analysis using specific complementary DNA probes. Distribution of BMP-2 in pancreatic cancers was examined by immunohistochemistry and in situ hybridization. Effects of BMP-2 on mitogenesis were assessed by monitoring cell proliferation and activation of mitogen-activated protein kinase (MAPK). Results: Compared with the normal pancreas, pancreatic cancers showed a 12.5-fold (P < 0.01), 2-fold (P < 0.01), and 8-fold (P < 0.01) increase of BMP-2, BMP receptor (R)-IA, and BMPR-II messenger RNA levels, respectively. By immunohistochemistry and in situ hybridization, BMP-2 was expressed in the cancer cells within the tumor mass. There was a significant correlation between the presence of BMP-2 immunostaining in the tumors and shorter postoperative survival. Pancreatic cancer cell lines expressed variable levels of messenger RNA encoding BMP-2 and its receptors. BMP-2 stimulated the growth of two pancreatic cancer cell lines (ASPC-1 and CAPAN-1). This mitogenic effect was associated with MAPK activation and blocked by the MAPK inhibitor PD98059 in CAPAN-1 but not in ASPC-1 cells. In both cell lines, expression of wild-type Smad4 abolished the BMP-2–mediated growth stimulation. BMP-2 inhibited the growth of COLO-357 cells, an effect that was blocked by expressing a dominant negative Smad4. BMP-2 had no effect in three cell lines that underexpressed either the BMP receptors or Smad1. Conclusions: These findings indicate that BMP-2 has the capacity to act as a mitogen when Smad4 is mutated and suggest that it might play a role in the pathobiology of human pancreatic cancer.

GASTROENTEROLOGY 1999;116:1202-1216

Section snippets

Materials

The following materials were purchased: fetal bovine serum, Dulbecco's modified Eagle medium (DMEM), trypsin solution, and penicillin-streptomycin solution from Irvine Scientific (Santa Ana, CA); Genescreen membranes from New England Nuclear (Boston, MA); restriction enzymes, Genius 3 nucleic acid detection kit, and random primed labeling kit from Boehringer Mannheim (Indianapolis, IN); Sequenase version 2.0 DNA Sequencing from United States Biochemical (Cleveland, OH); [α-32P]deoxycytidine

Expression of BMP-2, BMPR-IA, BMPR-IB, and BMPR-II in human pancreatic tissues

Northern blot analysis of total RNA isolated from normal human pancreatic tissue revealed a faint BMP-2 messenger RNA (mRNA) transcript (approximately 3.4 kb)26 that was visible on the original autoradiographs in 11 of 12 normal pancreatic samples (Figure 1) and in 12 of 14 chronic pancreatitis samples (Figure 2A).

. Expression of BMP-2 and its receptors in human pancreatic cancer. Total RNA (20 μg/lane) from 6 normal and 8 cancerous human pancreatic tissues were subjected to Northern blot

Discussion

BMP-2 is synthesized as a large precursor that is processed to yield the active BMP-2 protein dimer.6 BMP-2 was originally isolated as a peptide capable of inducing ectopic cartilage formation in vivo.5 BMP-2 is now known to participate in many biological processes in both vertebrates and invertebrates.5 BMP expression has been reported in prostate,33, 34 gastric,35 colorectal, thyroid, and bladder cancer cell lines.36 Expression of BMPs has also been observed in human tumors such as prostate

Acknowledgements

The authors thank Prof. Dr. J. Husler and A. Gemperli, Department of Mathematical Statistics, University of Bern, Switzerland, for statistical support.

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  • Cited by (0)

    Address requests for reprints to: Murray Korc, M.D., Division of Endocrinology, Diabetes and Metabolism, Medical Sciences I, C240, University of California, Irvine, California 92697. e-mail: [email protected]; fax: (949) 824-1035.

    ☆☆

    Supported by U.S. Public Health Service grants CA-75059 and CA-40162 (to M.K.) and by a fellowship award from the University of California Research and Education Grant on Gene Therapy for Cancer (to J.K.).

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