Prevention of metastatic pancreatic cancer growth in vivo by induction of apoptosis with genistein, a naturally occurring isoflavonoid

INTRODUCTION

The critical need for novel therapeutic approaches to pancreatic cancer treatment is clear. Genistein, a naturally occurring isoflavonoid, is active against certain solid malignancies, but its effect on pancreatic cancer is unknown.

AIMS

To investigate the bioactivity of genistein in experimental pancreatic cancer in vitro and in vivo.

METHODOLOGY

The effect of intraperitoneal genistein administration on local tumor growth and metastatic disease was determined in an orthotopic nude mouse model. Apoptosis in tumor specimens was determined by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) technique. In vitro, the effect of genistein on cell growth was assessed by cell count and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) colorimetric assay. Apoptosis was determined in vitro by DNA laddering and annexin-V. Caspase-3 and nuclear factor-kappaB activity were measured following genistein treatment.

RESULTS

In vivo, genistein significantly improved survival, almost completely inhibited metastasis, and increased apoptosis in an orthotopic model of pancreatic cancer. In vitro genistein treatment resulted in apoptosis in all pancreatic cancer cell lines tested, and this appeared to be mediated by activation of caspase-3.

CONCLUSION

These findings suggest that the antimetastatic effect of genistein treatment in vivo is mediated by induction of apoptosis. Genistein may have a therapeutic benefit for patients with pancreatic cancer, in particular after surgery, to prevent recurrence of metastatic disease.

Therapy for pancreatic cancer with a recombinant humanized anti-HER2 antibody (herceptin)

The HER2/neu oncogene is overexpressed in human pancreatic cancer, but the clinical significance of that overexpression is uncertain. In the present study we investigated the antitumor efficacy of Herceptin, a new recombinant humanized anti-HER2/neu antibody, which exhibits cytostatic activity on breast and prostate cancer cells that overexpress the HER2 oncogene. That antibody may retard tumor growth in certain patients with those diseases. We quantified HER2 expression in various human pancreatic cancer cell lines and studied the bioactivity of this antibody both in vitro and in vivo. Growth inhibition by Herceptin was observed in vitro in cell lines with high levels of HER2/neu expression. Cell lines with low levels of this protein did not respond significantly to the antibody. In vivo we studied two different pancreatic cancer cell lines in an orthotopic mouse model of the disease. Herceptin treatment suppressed tumor growth in the MIA PaCa-2 tumor cell line, which expressed high levels of HER2/neu. These data suggest that Herceptin treatment of patients with pancreatic cancer who express high levels of the HER2/neu oncogene may be reasonable.