Benjamin M Milam

Publications (2)5.55 Total impact

• Article: Apigenin inhibits the GLUT-1 glucose transporter and the phosphoinositide 3-kinase/Akt pathway in human pancreatic cancer cells.

  Laleh G Melstrom, Mohammad R Salabat, Xian-Zhong Ding, Benjamin M Milam, Matthew Strouch, Jill C Pelling, David J Bentrem
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  ABSTRACT: The antiproliferative mechanisms of flavonoid drugs inpancreatic cancer cells remain unclear. In this study, we evaluated the effects of the flavonoid apigenin on glucose uptake, on the expression of the glucose transporter 1 (GLUT-1), and on the phosphoinositide 3-kinase (PI3K)/Akt pathway in human pancreatic cancer cells. Human pancreatic cancer cells were treated with apigenin and then underwent glucose uptake assays. Real-time reverse transcription-polymerase chain reaction and Western blot analysis were conducted to evaluate GLUT-1 and pAkt expression in CD18 and S2-013 human pancreatic cancer cells after treatment with apigenin or PI3K inhibitors (LY294002 and wortmannin). Apigenin (0-100 microM) significantly inhibited, in a dose-dependent fashion, glucose uptake in CD18 and S2-013 human pancreatic cancer cell lines. Apigenin inhibited both GLUT-1 mRNA and protein expression in a concentration- and time-dependent fashion. The PI3K inhibitors, like apigenin, downregulated both GLUT-1 mRNA and protein expression. Our results demonstrate that the flavonoid apigenin decreases glucose uptake and downregulates the GLUT-1 glucose transporter in human pancreatic cancer cells. In addition, the inhibitory effects of apigenin and the PI3K inhibitors on GLUT-1 are similar, indicating that the PI3K/Akt pathway is involved in mediating apigenin's effects on downstream targets such as GLUT-1.
  Pancreas 12/2008; 37(4):426-31. · 2.39 Impact Factor
• Article: Geminin is overexpressed in human pancreatic cancer and downregulated by the bioflavanoid apigenin in pancreatic cancer cell lines.

  Mohammad R Salabat, Laleh G Melstrom, Matthew J Strouch, Xian-Zhong Ding, Benjamin M Milam, Michael B Ujiki, Catherine Chen, Jill C Pelling, Sambasiva Rao, Paul J Grippo, Thomas J McGarry, David J Bentrem
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  ABSTRACT: Pancreatic adeniocarcinoma is among the deadliest of human cancers. Apigenin, an antitumor flavonoid, inhibits pancreatic cancer cell proliferation in vitro. Geminin is a recently identified novel protein that plays a critical role in preventing abnormal DNA replication by binding to and inhibiting the essential replication factor Cdt1. Microarray analysis identified geminin to be downregulated in pancreatic cancer cells treated with apigenin. Therefore, we investigated the effects of apigenin on geminin expression and other proteins involved in replication (Cdc6, Cdt1, and MCM7) in pancreatic cancer cell lines CD18 and S2013. Real time RT-PCR and western blotting analysis showed that geminin expression is downregulated by apigenin at both mRNA and protein levels. Furthermore, treatment of cells with proteosome inhibitor MG132 reversed the downregulation of geminin by apigenin, supporting our hypothesis that the degradation pathway is another mechanism by which apigenin affects geminin expression. Apigenin treatment also resulted in downregulation of Cdc6 at both mRNA and protein levels. However, Cdt1 and MCM7 expression was not affected in apigenin-treated cells. The effect of apigenin treatment on geminin promoter activity was measured by transient transfection of Hela cells with a reporter gene, demonstrating that apigenin inhibited geminin promoter activity. Geminin expression was also evaluated in human pancreatic tissue (n = 15) by immunohistochemistry and showed that geminin is overexpressed in human pancreatic cancer compared to normal adjacent pancreatic tissue. In conclusion, our studies demonstrated that geminin is overexpressed in human pancreatic cancer and downregulated by apigenin which may contribute to the antitumor effect of this natural flavonoid.
  Molecular Carcinogenesis 05/2008; 47(11):835-44. · 3.16 Impact Factor