Carcinogenesis vol.22 no.1 pp.187–191, 2001
SHORT COMMUNICATION
Expression of 15-lipoxygenase-1 is regulated by histone acetylation
in human colorectal carcinoma
Hideki Kamitani1,2, Seijiro Taniura1, Hiroshi Ikawa1,
Takashi Watanabe2, Uddhav P.Kelavkar3 and
Thomas E.Eling1,4
1Laboratory
of Molecular Carcinogenesis, National Institutes of
Environmental Health Sciences, Research Triangle Park, NC 27709, USA,
2Division of Neurosurgery, Institute of Neurological Sciences, Tottori
University School of Medicine, 36-1 Nishi-cho, Yonago 683-0805, Japan
and 3Renal Division and Glomerulonephritis Center, Emory University,
Atlanta, GA 30322, USA
4To
whom correspondence should be addressed
Email: [email protected]
15-Lipoxygenase-1 (15-LO-1) is expressed at higher levels
in human colorectal tumors compared with normal tissue.
15-LO-1 is expressed in cultured human colorectal cells,
but only after treatment with sodium butyrate (NaBT),
which also stimulates apoptosis and cell differentiation. We
examined the regulation of 15-LO-1 in human tissue and
the colorectal carcinoma cell lines Caco-2 and SW-480 by
treatment with histone deacetylase (HDAC) inhibitors:
NaBT, trichostatin A (TSA) and HC toxin. Northern and
western analysis showed that expression of 15-LO-1 was
up-regulated by these HDAC inhibitors. Furthermore,
HDAC inhibitors stimulated promoter activity of the 15LO-1 gene ~12- to 21-fold using the –331/–23 region of the
15-LO-1 promoter, as measured with a luciferase–15-LO1 promoter–reporter system, suggesting that 15-LO-1 is
regulated at the transcriptional level by HDAC inhibitors.
Histone proteins in colorectal cells were acetylated after
treatment with HDAC inhibitors. Histone acetylation was
also measured in human colorectal tissue and a correlation
was observed between increased histone acetylation and
15-LO-1 expression. Thus, regulation of 15-LO-1 expression
in colorectal tissues appears to occur by a novel and new
mechanism associated with histone acetylation. Moreover,
these results suggest that 15-LO-1 is a marker that reflects
histone acetylation in colorectal carcinoma.
Reticulocyte-type 15-lipoxygenase (15-LO-1) oxidizes C18
fatty acids such as linoleic acid (1), lipoproteins (2) and also
more complex substrates such as biomembranes (3). 15-LO-1
is expressed during distinct stages of reticulocyte development
(4), in macrophages of atherosclerotic lesions (5) and in the
eye lens during organelle degradation (6). These findings
suggest that expression of 15-LO-1 is associated with maturation, senescence, membrane degradation and atherosclerosis.
We recently demonstrated expression of 15-LO-1 in human
colorectal carcinoma tissue (7) and in human colorectal carcinoma Caco-2 cells during sodium butyrate (NaBT)-induced
apoptosis and cell differentiation (8). Understanding the regulatory mechanism for 15-LO-1 gene expression may provide
clues to elucidate the biological role of 15-LO-1. The regulation
Abbreviations: FBS, fetal bovine serum; H4, histone 4; HDAC, histone
deacetylase; 15-LO-1, 15-lipoxygenase-1; NaBT, sodium butyrate; TSA,
trichostatin A.
© Oxford University Press
of 15-LO-1 expression is poorly understood but it is known
that IL-4 and IL-13 up-regulate 15-LO-1 in monocytes (9) and
airway cells (10) through the STAT-6 pathway (11). However,
the regulatory mechanism for induction of 15-LO-1 by NaBT
in Caco-2 cells (8) may be different. Butyrate is a short-chain
fatty acid, a product of fermentation of luminal carbohydrates
and is found in millimolar concentrations in the lumen of the
intestinal epithelium (12). NaBT induces hyperacetylation of
histones by inhibiting histone deacetylation and is pharmacologically categorized as a histone deacetylase (HDAC) inhibitor.
Recently there has been considerable interest in transcriptional
regulation by histone acetylation. For example, HDAC inhibitors modulate the expression of several genes, such as γ-globin
(13), p21WAF1 (14), gelsolin (15) and myb (16) in cultured cells
To examine whether expression of 15-LO-1 is regulated by
histone acetylation, expression of 15-LO-1 was measured by
northern analysis after treatment of the colorectal carcinoma
cell lines Caco-2 and SW-480 for 24 h with the HDAC
inhibitors NaBT, trichostatin A (TSA) (17) and HC toxin (18).
Cells grown under normal culture condition [fetal bovine
serum (FBS)] did not express 15-LO-1, but NaBT, TSA and
HC toxin induced 15-LO-1 expression in both cells (Figure
1A). The 2.7 kb band is reported to be the translated region
and the 4.0 kb band is reported to contain the untranslated
region (20). Additional bands observed between 2.7 and 4.0
kb in SW-480 cells are presumed to be the result of alternative
splicing. Since hypermethylation in a promoter region of a
gene can be related to HDAC activity (21), we measured
expression of 15-LO-1 after treatment with the demethylating
agent 5-azacytidine. However, no induction of 15-LO-1 was
observed in either cell line treated with 500 nM 5-azacytidine
(Figure 1A).
15-LO-1 protein expression was estimated after treatment
with HDAC inhibitors by Western analysis using an antibody
specific for 15-LO-1. The cells were cultured with or without
HDAC inhibitors for 48 h, then harvested and lysates prepared.
After treatment of Caco-2 and SW-480 cells with the HDAC
inhibitors a 72 kDa immunoreactive band was detected in
these cell lysates (Figure 1B).
Since 15-LO-1 expression was increased by HDAC inhibitors, we investigated whether HDAC inhibitors can stimulate
activity of the 15-LO-1 gene promoter. Two different promoter–
reporter constructs, –628/–23pGL2 and –331/–23pGL2, were
used for this study (Figure 2A). We also used the pGL2-Basic
reporter plasmid, which lacks the promoter region of 15-LO1, as a negative control. The relative luciferase activity and
fold activation by HDAC inhibitors were determined in Caco2 and SW-480 cells incubated with each of the three HDAC
inhibitors. Fold activation using the pGL2-basic reporter was
⬍1.4 in Caco-2 cells (Figure 2B) and ⬍1.6 in SW-480 cells
(Figure 2C) after treatment with the inhibitors. On the other
hand, 6.2-, 9.0- and 6.4-fold activation of the –628/–23pGL2
reporter was observed after incubation with NaBT, TSA and
HC toxin, respectively, in Caco-2 cells, while 1.8-, 2.1- and
187
H.Kamitani et al.
Fig. 1. Induction of 15-LO-1 expression in Caco-2 and SW-480 cells by
treatment with HDAC inhibitors. Caco-2 cells were grown in Eagle’s
minimal essential medium and SW-480 cells were grown in IMEM as
described previously (8). (A) Northern blot analysis using a human 15-LO-1
specific probe of total cellular RNA (20 µg/sample). Lanes 1–5, Caco-2
cells treated for 24 h; lanes 6–10, SW-480 cells treated for 24 h. Lanes 1
and 6, FBS; lanes 2 and 7, 5 mM NaBT; lanes 3 and 8, 1 µg/ml TSA; lanes
4 and 9, 200 nM HC toxin; lanes 5 and 10, 500 nM 5-azacytidine (a
demethylating agent). (B) Immunoblot analysis. Caco-2 and SW-480 cells
were treated with HDAC inhibitors for 48 h and the proteins extracted.
Expression of 15-LO-1 was estimated as described previously (8). Each lane
contains 40 µg of total cell lysate and samples were separated on an 8%
SDS–polyacrylamide gel. Lane 1, standard 15-LO-1 protein.
2.3-fold activation was detected after treatment of SW-480
cells with NaBT, TSA and HC toxin. Interestingly, stronger
activation was detected by transfection of both cell lines with
the –331/–23pGL2 reporter. Caco-2 cells showed 17-fold
activation with NaBT, 21.3-fold with TSA and 19.5-fold with
HC toxin, while SW-480 cells showed fold activations of 11.9
with NaBT, 19.9 with TSA and 19.1 with HC toxin. These
observations indicate that the promoter region of 15-LO-1 is
activated by the HDAC inhibitors in Caco-2 and SW-480 cells.
In addition, either a distal region of the 5⬘-flanking region
within 331 bp appears to be involved in transactivation of the
15-LO-1 gene by HDAC inhibitors or a repressor region is
present upstream of 331 bp.
One of the prime pharmacological effects of HDAC inhibitors is an increase in acetylation of core histones (22).
Moreover, accumulating evidence suggests that acetylation and
deacetylation of histones play significant roles in the regulation
of transcription in eukaryotic cells (23). To ascertain whether
treatment with NaBT, TSA or HC toxin leads to acetylation
188
Fig. 2. Stimulation of 15-LO-1 promoter activity in Caco-2 and SW-480
cells by HDAC inhibitors. (A) Human 15-LO-1 promoter–reporter
constructs. Each fragment of the 5⬘-flanking region from –628 to –23 and
from –331 to –23 was constructed in the pGL2-Basic luciferase reporter
plasmid as –628/–23pGL2 and –331/–23pGL2, respectively (B and C). The
constructed plasmids –628/–23pGL2, –331/–23pGL2 and pGL2-Basic in
combination with pRL-null were transiently transfected into Caco-2 cells
(B) and SW-480 cells (C) and luciferase activities were analyzed after 48 h
treatment with FBS, 5 mM NaBT, 1 µg/ml TSA or 200 nM HC toxin. For
transfection, cells were plated in 6-well plates at a density of 1⫻105 cells/
well and incubated in FBS medium for 24 h. After washing the cells with
phosphate-buffered saline, 1 mg luciferase reporter and 10 ng pRL-null
internal control construct (Promega) were transfected using 5 ml of
LipofectAMINE. The medium was replaced after 6 h with medium with and
without the HDAC inhibitors and the cells incubated for 48 h. Luciferase
activity is expressed as relative luciferase activity: firefly luciferase signal/
renilla luciferase signal. Fold activation by HDAC inhibitors is also
calculated for each condition. Data shown are means ⫾ SE (n ⫽ 3).
of core histones in Caco-2 and SW-480 cells, acid-extractable
proteins were analyzed (Figure 3). As reported previously
(24), histone 4 (H4) exhibits the best resolution among histones.
After FBS treatment H4 was in the unacetylated form in both
HDAC inhibitors and 15-lipoxygenase-1
Fig. 4. H4 acetylation and expression of 15-LO-1 in human colorectal
carcinoma tissue. Surgically resected colorectal tumor samples and adjacent
normal tissues were obtained from the University of North Carolina,
Lineberger Comprehensive Cancer Center. Equal amounts (20 µg) of total
protein isolated from samples were separated by 8% PAGE for analysis of
15-LO-1. Ten micrograms of histone from each sample were separated by
18% PAGE for analysis of acetylated H4. Anti-acetylated H4 antibody
(Upstate Biotechnology) was used to detect the acetylated H4 antibody.
Lane C, 15-LO-1 standard; lanes 1–4, normal tissues adjacent to the
colorectal carcinoma; lanes 5–7, colorectal carcinoma tissues; lane 8,
FBS-treated Caco-2 cells; lane 9, NaBT-treated Caco-2 cells.
Fig. 3. Histone acetylation in Caco-2 and SW-480 cells induced by HDAC
inhibitors. The cell pellets were washed twice with 0.5 ml lysis buffer (10
mM Tris, pH 8.0, 13 mM EDTA) and resuspended in 0.4 N H2SO4. Cells
were incubated on ice for 1 h, followed by centrifugation at 10 000 g for
5 min. Total histones were precipitated from the supernatant with 10⫻
volumes of acetone at –20°C overnight. The precipitated histones were
collected by centrifugation, dried and resuspended in distilled water. Histone
acetylation was evaluated by fractioning the histones on acid/urea/
polyacrylamide gels. The lower gel was 15% acrylamide, 2.5 M urea, 5%
acetic acid with 0.5% TEMED and 0.15% ammonium persulfate. Gels were
fixed and stained for 1 h in 0.25% Coomassie blue, 10% acetic acid, 40%
methanol, then destained with repeated changes of acid/methanol. Cells
were treated for 24 h with FBS, 5 mM NaBT, 1 µg/ml TSA or 200 nM HC
toxin. The identities of the H4 bands were verified with standard H4 (lane
5). Acetylated H4 showed slower migration than unacetylated H4.
Caco-2 and SW-480 cells and a single band was detected.
Incubation with NaBT, TSA or HC toxin for 20 h led to a
large increase in the tri- and tetra-acetylated forms of H4 and
thus several additional bands were observed in the H4 region.
This observation indicates that incubation with the HDAC
inhibitors increased acetylation of histones in Caco-2 and
SW-480 cells.
We next evaluated whether the histones are acetylated in
colorectal tissues that express 15-LO-1. Expression of 15-LO1 and acetylated H4 were measured by immunoblotting as
shown in Figure 4. Seven surgical samples, four from adjacent
normal tissues (lanes 1–4 in Figure 4) and three from colorectal
carcinoma tissues (lanes 5–7 in Figure 4), from patients with
colon carcinoma were examined. Total proteins and histone
fractions isolated from FBS- and NaBT-treated Caco-2 cells
served as negative and positive controls (lanes 8 and 9 in
Figure 4). 15-LO-1 was expressed in the samples in lanes 1,
4–7 and 9, while acetylated H4 was detected in the samples
in lanes 1, 5–7 and 9. Except for lane 4, which is adjacent
normal tissue, 15-LO-1 expression and histone acetylation
evaluated by detection of acetylated H4 appear to be linked.
Moreover, the tissues with higher expression of 15-LO-1 also
showed greatest expression of acetylated H4.
15-LO-1 is highly regulated and its expression is restricted
to specific mammalian cells and tissues. For example, expression of rabbit reticulocyte 15-LO is observed during erythroid
cell differentiation (25) and is regulated by binding of hnRNP
K and hnRNP E1 to the 3⬘-untranslated region of 15-LO
mRNA. Other studies with normal undifferentiated human
tracheal epithelial cells in culture showed that 15-LO-1 expression was only observed after differentiation to mucociliary
epithelium (26). Likewise, the undifferentiated human colorectal carcinoma cells Caco-2 and SW-480 do not express 15-LO1 unless the cells are stimulated to undergo apoptosis and cell
differentiation, when 15-LO-1 expression is observed. Thus,
expression is tightly regulated and appears to be associated
with cell differentiation. Treatment of colorectal cells with
HDAC inhibitors causes differentiation and apoptosis in Caco2 (8) and SW-480 cells (data not shown) and increases
expression of 15-lipoxygenase at the transcription level, suggesting a possible relationship between histone acetylation,
regulation of 15-LO-1 expression and cell differentiation/
apoptosis.
Histone acetylation is associated with transcriptional activity
in eukaryotic cells (27). Recently the relationship between
histone acetylation and transcription regulatory mechanisms
has been clarified (23,24). Acetylation occurs at lysine residues
on the N-terminal tails of histones, resulting in alterations in
nucleosomal conformation, thus increasing the accessibility of
transcription regulatory proteins to chromatin templates (28).
It is unclear why a particular gene is transcriptionally regulated
by histone acetylation. A specific transcription factor must be
considered an important player in this regulation. The 5⬘flanking region from –331 to –23 is important in activation of
the 15-LO-1 gene by HDAC inhibitors in both Caco-2 and
189
H.Kamitani et al.
SW-480 cells (Figure 2). GATA-binding sites, a share-stress
response element, (20) Sp1 and TATA sites are included in
this region, but we could not identify the specific site within
this region responsible for activation of 15-LO-1. There are a
few reports about the involvement of a transcription factor in
gene activation by HDAC inhibitors. The Sp1 site is responsible
for activation of p21WAF/Cip1 in colon cancer cells after treatment
with HDAC inhibitors (29) and in osteosarcoma cells (30).
The distal CCAAT box and the 3⬘-flanking sequence (CCAATAGAC) are critical in induction of γ-globin by HDAC inhibitors
in human leukemia cells, as reported by McCaffrey et al. (13).
However, none of the above reports showed a differential
interaction between the critical promoter region and a particular
transcription factor after treatment with HDAC inhibitors.
We have previously demonstrated an ~2- to 3-fold higher
expression of 15-LO-1 in colorectal carcinomas as compared
with adjacent normal tissues from cancer patients (7). The
results from this study suggest a correlation between high
expression of 15-LO-1 and expression of acetylated H4 (Figure
4), which was most apparent in carcinoma tissues. This finding
may provide a clue as to why 15-LO-1 is highly expressed in
human colorectal tissues, especially in the epithelial region.
Short-chain fatty acids such as acetate, propionate, and butyrate
are produced when dietary fiber is fermented by colonic
bacteria (31). As a result, the colorectal epithelium is exposed
to these short-chain fatty acids and 15-LO-1 expression occurs.
However, why histones in carcinoma tissues are more highly
acetylated than those in normal tissues is still unclear. Since
15-LO-1 expression correlates with histone acetylation, 15LO-1 would be a suitable marker for colorectal carcinoma
exposed to HDAC inhibitors such as butyrate. Because HDAC
inhibitors stimulate cell cycle arrest (32) and apoptosis/cell
differentiation (8), colorectal epithelial cells or tissues
expressing 15-LO-1 could be a marker indicating cessation of
proliferation in colorectal carcinoma. In contrast to our previous
data (7), Shureiqi et al. (33) reported on increased expression
of 15-LO-1 in normal colonic epithelium compared with paired
colorectal carcinoma tissue by immunohistochemistry. The
difference in 15-LO-1 expression between their samples and
ours is not clear, but may depend on the extent of histone
acetylation in each sample. Further investigation is required
to clarify the importance of expression of 15-LO-1 in colorectal
cancer. In conclusion, our data support the hypothesis that
histone acetylation stimulated by HDAC inhibitors is strongly
linked to expression of 15-LO-1 in colorectal tissues.
Acknowledgements
We thank Dr Benjamin Calvo (University of North Carolina, NC) for providing
the human colorectal carcinoma samples. We also thank Mark Geller for his
technical assistance and Drs Linda Hsi and Jennifer Nixon for their critical
reading of the manuscript.
References
1. Yamamoto,S. (1992) Mammalian lipoxygenases: molecular structures and
functions. Biochim. Biophys. Acta, 1128, 117–131.
2. Belkner,J., Stender,H. and Kuhn,H. (1998) The rabbit 15-lipoxygenase
preferentially oxygenates LDL cholesterol esters and this reaction does
not require vitamin E. J. Biol. Chem., 273, 23225–23232
3. Kuhn,H., Belkner,J., Wiesner,R. and Brash,A.R. (1990) Oxygenation of
biological membranes by the pure reticulocyte lipoxygenase. J. Biol.
Chem., 265, 18351–18361.
4. Rapoport,S.S.T. (1986) The maturational breakdown of mitchondria in
reticulocytes. Biochim. Biophys. Acta, 864, 471–495.
5. Yla-Herttuala,S., Rosenfeld,M.E., Pathasarathy,S., Glass,C.K., Sigal,E.,
Witztum,J.L. and Steinberg,D. (1990) Colocalization of 15-lipoxygenase
190
mRNA and protein with epitopes of oxidized low density lipoprotein in
macrophage-rich areas of artherosclerotic lesions. Proc. Natl Acad. Sci.
USA, 87, 6959–6963.
6. van Leyen,K., Duvoisin,R.M., Engelhardt,H. and Wiedmann,M. (1998) A
function for lipoxygenase in programmed organelle degradation. Nature,
395, 392–395.
7. Ikawa,H., Kamitani,H., Calvo,B.F., Foley,J.F. and Eling,T.E. (1999)
Expression of 15-lipoxygenase-1 in human colorectal cancer. Cancer Res.,
59, 360–366.
8. Kamitani,H., Geller,M. and Eling,T.E. (1998) Expression of 15lipoxygenase by human colorectal carcinoma Caco-2 cells during apoptosis
and cell differentiation. J. Biol. Chem., 273, 21569–21577.
9. Conrad,D.J., Kuhn,H., Mulkins,M., Highland,E. and Sigal,E. (1992)
Specific inflammatory cytokines regulate the expression of human
monocyte 15-lipoxygenase. Proc. Natl Acad. Sci. USA, 89, 217–221.
10. Jayawickreme,S.P., Gray,T., Nettesheim,P. and Eling,T.E. (1999) Regulation
of 15-lipoxygenase expression and mucus secretion by IL-4 in human
bronchial epithelial cells. Am. J. Physiol., 276, L596–L603.
11. Heydeck,D., Thomas,L., Schnurr,K., Trebus,F., Thierfelder,W.E., Ihle,J.N.
and Kuhn,H. (1998) Interleukin-4 and -13 induce upregulation of the murine
macrophage 12/15-lipoxygenase activity: evidence for the involvement of
transcription factor STAT6. Blood, 92, 2503–2510.
12. Kruh,J. (1982) Effects of sodium butyrate, a new pharmacological agent,
on cells in culture. Mol. Cell. Biochem., 42, 65–82.
13. McCaffrey,P.G., Newsome,D.A., Fibach,E., Yoshida,M. and Su,M.S. (1997)
Induction of gamma-globin by histone deacetylase inhibitors. Blood, 90,
2075–2083.
14. Archer,S.Y., Meng,S., Shei,A. and Hodin,R.A. (1998) p21(WAF1) is
required for butyrate-mediated growth inhibition of human colon cancer
cells. Proc. Natl Acad. Sci. USA, 95, 6791–6796.
15. Saito,A., Yamashita,T., Mariko,Y., Nosaka,Y., Tsuchiya,K. Ando,T.,
Suzuki,T., Tsuruno,T. and Nakanishi,O. (1999) A synthetic inhibitor of
histone deacetylase, MS-27-275, with marked in vivo antitumor activity
against human tumors. Proc. Natl Acad. Sci. USA, 96, 4592–4597.
16. Thompson,M.A., Rosenthal,M.A., Ellis,S.L., Friend,A.J., Zorbas,M.I.,
Whitehead,R.H. and Ramsay,R.G. (1998) c-Myb down-regulation is
associated with human colon cell differentiation, apoptosis and decreased
Bcl-2 expression. Cancer Res., 58, 5168–5175.
17. Yoshida,M., Kijima,M., Akita,M. and Beppu,T. (1990) Potent and specific
inhibition of mammalian histone deacetylase both in vivo and in vitro by
trichostatin A. J. Biol. Chem., 268, 17174–17179.
18. Brosch,G., Ransom,R., Lechner,T., Walton,J.D. and Loidl,P. (1995)
Inhibition of maize histone deacetylases by HC toxin, the host-selective
toxin of Cochliobolus carbonum. Plant Cell, 7, 1941–1950.
19. Kelavkar,U., Wang,S., Montero,A., Murtagh,J., Shah,K. and Badr,K. (1998)
Human 15-lipoxygenase gene promoter: analysis and identification of
DNA binding sites for IL-13-induced regulatory factors in monocytes.
Mol. Biol. Rep., 25, 173–182.
20. Kritzik,M.R., Ziober,A.F., Dicharry,S., Conrad,D.J. and Sigal,E. (1997)
Characterization and sequence of an additional 15-lipoxygenase transcript
and of the human gene. Biochim. Biophys. Acta, 1352, 267–281.
21. Cameron,E., Bachman,K., Myohanen,S., Heman,J. and Baylin,S. (1999)
Synergy of demethylation and histone deacetylase inhibition in the reexpression of genes silenced in cancer. Nature Genet., 21, 103–107.
22. Candido,E.P., Reeves,R. and Davie,J.R. (1978) Sodium butyrate inhibits
histone deacetylation in cultured cells. Cell, 14, 105–113.
23. Struhl,K. (1998) Histone acetylation and transcriptional regulatory
mechanisms. Genes Dev., 12, 599–606.
24. Ogryzko,V.V., Schiltz,R.L., Russanova,V., Howard,B.H. and Nakatani,Y.
(1996) The transcriptional coactivators p300 and CBP are histone
acetyltransferases. Cell, 87, 953–959.
25. Ostareck-Lederer,A., Ostareck,D.H., Standart,N. and Thiele,B.J. (1994)
Translation of 15-lipoxygenase mRNA is inhibited by a protein that binds
to a repeated sequence in the 3⬘ untranslated region. EMBO J., 13,
1476–1481.
26. Hill,E.M., Eling,T.E. and Nettesheim,P. (1998) Changes in expression of
15-lipoxygenase and prostaglandin-H synthase during differentiation of
human tracheobronchial epithelial cells. Am. J. Respir. Cell Mol. Biol.,
18, 662–669.
27. Allfrey,V., Faulkner,R.M. and Mirsky,A.E. (1964) Acetylation and
methylation of histones and their possible role in the regulation of RNA
synthesis. Proc. Natl Acad. Sci. USA, 51, 786–794.
28. Vettese-Dadey,M., Grant,P.A., Hebbes,T.R., Crane-Robinson,C., Allis,C.D.
and Workman,J.L. (1996) Acetylation of histone H4 plays a primary role
in enhancing transcription factor binding to nucleosomal DNA in vitro.
EMBO J., 15, 2508–2518.
HDAC inhibitors and 15-lipoxygenase-1
29. Nakano,K., Mizuno,T., Sowa,Y., Orita,T., Yoshino,T., Oekuyama,Y.,
Fujita,T., Ohtani-Fujita,N., Matsukawa,Y., Tokino,T., Yamagishi,H.,
Oka,T., Nomura,H. and Sakai,T. (1997) Butyrate activates the WAF/Cip1
gene promoter through Sp1 sites in a p53-negative human colon cancer
cell line. J. Biol. Chem., 272, 22199–22206.
30. Sowa,Y., Orita,T., Minamikawa,S., Nakano,K., Mizuno,T., Nomura,H. and
Sakai,T. (1997) Histone deacetylase inhibitor activates the WAF1/Cip1
gene promoter through the Sp1 sites. Biochem. Biophys. Res. Commun.,
241, 142–150.
31. Cummings,J.H. (1984) Short chain fatty acids in the human colon. Gut,
22, 763–779.
32. Heerdt,B.G., Houston,M.A., Anthony,G.M. and Augenlicht,L.H. (1998)
Mitochondrial membrane potential (delta psi(mt)) in the coordination of
p53-independent proliferation and apoptosis pathways in human colonic
carcinoma cells. Cancer Res., 58, 2869–2875.
33. Shureiqi,I., Wojno,K.J., Poore,J.A., Reddy,R.G., Moussalli,M.J.,
Spindler,S.A., Greenson,J.K., Normolle,D., Hasan,A.A.K., Lawrence,T.S.
and Brenner,D.E. (1999) Decreased 13-S-hydroxyoctadecadienoic acid
levels and 15-lipoxygenase-1 expression in human colon cancers.
Carcinogenesis, 20, 1985–1995
Received August 8, 2000; revised October 17, 2000;
accepted October 20, 2000
191