Butanol fraction containing berberine or related compound from nexrutine inhibits NFkappaB signaling and induces apoptosis in prostate cancer cells.
BACKGROUND
Epidemiological and laboratory studies support the hypothesis that several plant components influence prostate carcinogenesis and holds promise for disease prevention. Previously we reported that Nexrutine (bark extract from Phellodendron amurense) inhibits proliferation of prostate cancer cells and prostate tumor development in the transgenic adenocarcinoma of mouse prostate (TRAMP) model through modulation of Akt signaling pathway. In the present investigation we conducted studies to further define the mechanism of action of Nexrutine and to identify the active component associated with its biological activity.


METHODS
Androgen-responsive, androgen-independent human prostate cancer cell lines and tissues from TRAMP mice fed Nexrutine(R) were used in these studies. Activity guided fractionation identified butanol fraction recapitulating the activities of Nexrutine assessed by proliferation assays, apoptotic assays (DAPI and TUNEL staining), transient transfections, gel shift assays and Western blotting. In addition ultra-performance liquid chromatography (UPLC) of butanol fraction was used to identify active component of Nexrutine.


RESULTS
Butanol fraction recapitulated the activities of Nexrutine in (i) inhibiting proliferation; (ii) inducing apoptosis; and (iii) modulating transcriptional activity of NFkappaB in prostate cancer cells. Our data also indicates that both Nexrutine and butanol fraction modulates NFkappaB transcriptional activity by inhibiting IkappaBalpha phosphorylation. Expression of p65 and phosphorylated IkappaBalpha are high in tumors from TRAMP mice. In contrast dietary administration of Nexrutine reduced expression of p65 and phosphorylated IkappaBalpha in prostate from TRAMP mice. In addition using UPLC, we have identified berberine or closely related compound in the butanol fraction.


CONCLUSIONS
The results suggest that berberine or closely related component of butanol fraction may be responsible for the observed biological activities and induce apoptosis in prostate cancer cells by targeting critical cell survival signaling pathways both in vitro and in vivo.
Muralimanoharan
Sri Balasubashini
SB
Department of Urology, School of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA.
Kunnumakkara
A B
AB
Shylesh
Bhaskaran
B
Kulkarni
Kaustubh H
KH
Haiyan
Xu
X
Ming
Hu
H
Aggarwal
Bharat B
BB
Rita
Ghosh
G
Kumar
Addanki P
AP
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects*; D001599:Berberine / Q000494:pharmacology*; D000440:Butanols / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D008297:Male; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051996:Transcription Factor RelA / Q000378:metabolism
D000440:Butanols; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C512605:Nexrutine; C000606205:Nfkbia protein, mouse; D010936:Plant Extracts; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D051996:Transcription Factor RelA; D001599:Berberine; D000072000:NF-KappaB Inhibitor alpha; D051057:Proto-Oncogene Proteins c-akt