Michelle Mouria

Increased expression of glutamate decarboxylase (GAD67) in feline lumbar spinal cord after complete thoracic spinal cord transection

To determine changes in γ‐aminobutyric acid (GABA) in the spinal cord in response to a complete transection, we examined the cellular and tissue changes of the two forms of GABA synthetic enzyme glutamate decarboxylase (GAD65 and GAD67). In situ hybridization, immunohistochemistry, and Western blot analyses show that spinal cord transection between thoracic segments 12 and 13 results in an increase of GAD67, but not GAD65, protein and mRNA in the lumbar spinal cord. This increase occurs mainly in the dorsal horn and persists for at least 12 months. In addition, there was relatively high GAD67‐immunoreactivity around the central canal, with dorsolateral GAD67‐immunoreactive fibers extending toward the ependyma and into the central canal in the transected animals. We suggest that an increase in GAD67 leads to increased GABA production in spinal neurons below the injury site, resulting in altered inhibition and trophic support during posttrauma recovery and adaptation. Increased GABA synthesis around the central canal, in the vicinity of ependymal cells, may represent part of a regenerative process in the mammalian spinal cord, reminiscent of that observed in lower vertebrates. J. Neurosci. Res. 60:219–230, 2000

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–&kgr;B 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.