PRESENTED BY:DHARTI SHAH

DEPARTMENT OF NUTRITION AND FOOD SCIENCES

TEXAS WOMAN’S UNIVERSITYDENTON, TEXAS

The Role of Isoprenoids in Liver Cancer: A Review

SIGNIFICANCE OF THE STUDY

• Most rapidly increasing cancer type• Increased incidence in developed countries• Tumor suppressive effects of isoprenoids have been

shown in many cancers• A comprehensive review would provide a good

insight on the use of isoprenoids in liver cancer

METHODS

• Literature search was carried out using research databases

• Key words: o Mevalonate pathwayo Liver cancer

HBV, HCV, Aflatoxinso Molecular mechanisms in liver cancer o Isoprenoids

Farnesol Geraniol d-limonene, Perillyl alcohol geranylgeraniol

INTRODUCTION

• Cancer - second leading cause of death in U.S.• Estimated new cases and deaths in U.S. (all

cancers)o 2008 – 1,437,920; 565,650

• Liver cancer – 5th most common cancero 2007 – 19,160; 16,780o 2008 – 21,370; 18,410

• 5 year survival rate is < 3%

ACS http://www.cancer.org/docroot/CRI/content/CRI_2_2_1X_How_many_people_get_liver_cancer_25.asp?sitearea; Lencioni . et. al., Ital. J Gastroenterol, 1994

LIVER CANCER

• Primary liver cancers (PLC)o Hepatocellular carcinoma (HCC) – hepatocytes, most common

typeo Cholangiocarcinoma (CCA) – cells of intrahepatic bile ducts

• Global incidenceo > 80% of all cases in developing countrieso Increased incidence seen in developed countries

Srivatanakul et. al., Asian Pacific J Cancer Prev. ,2004

INCIDENCE IN UNITED STATES

• El-Serag et. al. confirm an increase in the number of HCC cases from 1975-1998o Study period divided into 7 3-year periodso Age groups (20-49, 50-64, 65-74, or ≥ 75 yrs)

• Resultso 2-fold increase in incidence of HCC between 1975-1998

Highest incidence seen among Asian migrants and Blacks 25% increase during the last 3 year period – Whites affected the

mosto Contributing factors

HBV - Asian countries (Southeast Asia) HCV – Black and White people

Needle sharing, drug use, blood transfusions

El-Serag et. al., Intern. Med., 2003

ETIOLOGY OF LIVER CANCER

• Major contributing factorso Hepatitis B (HBV)o Hepatitis C (HCV)o Aflatoxin-B1

• Minor contributing factorso Chronic alcoholism Cirrhosis HCC o Obesity Hepatic steatosis oxidative stresso Diabeteso Anabolic steroidso Toxins – arsenic, vinyl chloride

ACS http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_liver_cancer_25.asp?sitearea

HEPATITIS B X protein (HBX)

• HBV DNA fuses with cellular DNA – gene expression

Feitelson, Hum. Pathol., 2004

Tumor suppressive activity

HEPATITIS C (HCV)Core protein

• HCV core protein upregulates many oncogenic genes, including c-myc

• Hepatic steatosis – an independent risk factor in HCC

oxidation

Moriya et. al., J. Gen. Virol., 1997; Moriya et. al., Nat. Med., 1998; Ohata et. al., Cancer, 2003

Aflatoxin-B1

• Viral agents and environmental carcinogens - cancer • Aflatoxin exposure ---- G to T transversion in codon

249 of p53• HBV + aflatoxin interaction may be synergistic

o Liver injury as a result of HBV is a critical factor Increased expression of cytochrome P450’s that metabolize

carcinogens

Wild et. al., Environ. Health Persp., 1993; Eaton and Gallagher, Annu. Rev. Pharmacol. Toxicol, 1994; Hussain et. al., Oncogene, 1994

MOLECULAR EVENTS IN CANCER

CARCINOGENESIS

Murukami, et.al., Cancer Res., 1993

Malignancy

Protooncogenes Tumor suppressive genes Growth factors

OVERVIEW OF LIVER CANCER

• Hepatocytes altered phenotypically

Feitelson, Hum. Pathol., 2004; Anthony, J. Clin. Path., 1973; Thorgeirsson et. al., Nat. Genet., 2002

Protooncogenes and growth factors

• c-myc transcription factor cell growtho Early event in hepatocarcinogenesiso Hypomethylation of c-myco c-myc transgenic mice

Dysplastic changes – 2 months, well developed HCC – 15-18 months

• TGF-α active liver regenerationo Tumor progressiono TGF-α transgenic mice

Multifocal, well differentiated HCC – 10-15 months

Bhave et.al., Carcinogenesis, 1988; Sandgren et.al.,Oncogene,1989

Co-expression (c-myc-TGF-α)

• Dysplastic changes in hepatocytes• Apoptosis of healthy liver cells

Murukami et.al.,Cancer Res.,1993; Factor et.al.,Hepatology,2001

phosphorylated forms of ras and phosphoinositol-3 kinase

IĸB kinase (phosphorylated)

Nuclear factor κB

Apoptosis

C-myc-TGF-β1 and Hedgehog pathway

• Overexpression of TGF-β1 or c-myc/TGF-β1 o sensitivity of cells to TGFβ1

Overexpression of c-myc and loss of TGF-β II receptors HBV X and HCV core protein interfere with function of TGF-β1

• Hedgehog pathwayo Cell differentiationo expression of two target genes

PTCH1 and Gli1

Alexandrow et.al.,Cancer Res.,1995; Fynn et.al.,Crit.Rev.Oncog.,1993; Tsuchihara et.al.,Virology,1999; Huang et.al.,Carcinogenesis,2006

TNF-α

Nuclear factor-κB (NF-κB)

Proapoptotic genes

DNA damage

Arsura and Cavin,Cancer Lett.,2005

Anti-apoptotic genes

Carcinogens, viruses, growth factors

NF-κB

α-fetoprotein (AFP)

Cell survival

NF-κB’s role in liver cancer

• Rel/NF-κB (cytoplasm) transcription factorso Role studied in HBV positive Hep 3B cells

TGF-α

Chiao et.al.,Cancer,2002

releases

Rel/NF-κB

IκBα (phosphorylated)

Rel/NF-κB (cytoplasm) Rel/NF-κB (nucleus)

cell survival

IĸBα

c-Jun

• c-Jun component of activator protein 1 (AP-1)o Cell survival, cell cycle progressiono After initiation stage of tumor development

• Oncogenic activity of c-Juno N-terminal phosphorylationo Interaction with Raso Suppression of p53 o TNF-α induced NF-κB activity

Johnson et. al., Mol. Cell Biol., 1996; Eferl et. al., J. Cell Biol., 1999; Eferl et.al., Cell, 2003; Schreiber et. al., Genes Dev., 1999

Angiogenesis

• Multistep and a well coordinated process• Vascular endothelium specific angiogenic factors

Vascular endothelial growth factors(VEGF)

Angiopoietin family Ephrin family

Endothelium

AngiogenesisRac

Hypoxia induciblefactor 1α

NF-κB

Interleukin-6,8

Yancopoulas et. al., Nature, 2000; Arsura and Cavin, Cancer lett, 2005; Lee et.al., Clin. Cancer Res., 2006

MEVALONATE PATHWAY IN NORMAL CELLS

Acetyl CoA

HMG CoA

Mevalonate

Geranyl-PP

Farnesyl-PP

Cholesterol

Protein prenylationRas, lamin B Cell growth

FTase

HMG CoA reductase

Brown and Goldstein,Nature,1990; Goldstein et.al.,Cell,2006

Farnesol

Isopentenyl-5-PPDimethylallyl-PP

Isopentenyl-PPisomerase

SREBP pathway

MEVALONATE PATHWAY IN NORMAL CELLS

Acetyl CoA

HMG CoA

Mevalonate

Geranyl-PP

Farnesyl-PP

Cholesterol

Protein prenylationRas, lamin B Cell growth

FTase

HMG CoA reductase

Brown and Goldstein,Nature,1990; Goldstein et.al.,Cell,2006

Farnesol

Isopentenyl-5-PPDimethylallyl-PP

Isopentenyl-PPisomerase

MEVALONATE PATHWAY IN CANCER CELLS

Acetyl CoA

HMG CoA

Mevalonate

Geranyl-PP

Farnesyl-PP

Cholesterol

Protein prenylationRas, lamin B Cell growth

FTase

HMG CoA reductase

Brown and Goldstein,Nature,1990; Goldstein et.al.,Cell,2006

Farnesol

Isopentenyl-5-PPDimethylallyl-PP

Isopentenyl-PPisomerase

DYSREGULATED PATHWAY

• Reductase lacks active site or no conformational change occurs

• Hypomethylation of reductase gene• Mutation in SCAP protein

o Transition at one of the codons of SCAP• Increase in active form of HMG CoA reductase

o Altered enzyme kinase - phosphatase system

Siperstein and Fagan,Cancer Res.,1964; Vasudevan et.al.,FASEB J.,1994; Goldstein et.al.,Cell,2006; Kawata et.al.,Cancer Res.,1990

Reductase regulation in Hep G2 cells

Acetyl CoA

HMG CoA

Mevalonate

Geranyl-PP

Farnesyl-PP

Cholesterol

HMG CoA reductase

Farnesol

Isopentenyl-5-PP

Compactin

U18666A

Enzyme activity

Enzyme mRNA content

Cohen and Griffioen, Biochem. J.,1998

ISOPRENOIDS AND CANCER

• Secondary metabolites of mevalonate metabolism in plants

• Five carbon isoprene unitsISOPRENOIDS

Pure Mixed

• Monoterpenes – d-imonene (orange peel oil), Perillyl alcohol (lavender, cherries), Geraniol (berries)

Diterpenes – Geranylgeraniol• Sesquiterpenes – Farnesol

• Isoflavones • Tocotrienols

(vegetable oils, whole grains)

Blocking and suppressing agents

Elson and Yu, J. Nutr.,1994; Elson et. al., Proc. Soc.Exp.Biol.Med., 1999

Mechanism of action

• Isoprenoidso Cell cycle arresto Apoptosiso Degradation of HMG-CoA reductaseo Anti-angiogenico Inhibition of protein isoprenylation

CELL CYCLE ARREST

• Perillyl alcohol (POH), d-limonene, geraniol

Mo and Elson, Nutritional Oncology, 2006; Clark, Oncology, 2006; Packham and Cleaveland, Mol. Cell Biol., 1994

G1

S

G2

M

Cyclin/cdk complex

c-mycMitosisDNA replication

APOPTOSIS

• Geranylgeraniol (GGOH), Perillyl alcohol (POH)

Proapoptotic proteins(Bad, Bax)

Anti-apoptotic proteins(Bcl-2, Bcl-XL)

Caspase activity

Apoptosis

Masuda et.al., Leuk. Res., 2000

HMG CoA reductase inhibitors

Acetyl CoA

HMG CoA

Mevalonate

Geranyl-PP

Farnesyl-PP

Cholesterol

Protein prenylationRas, lamin B Cell growth

FTase

HMG CoA reductase

Crowell et.al., J. Biol. Chem., 1991; Hohl and Lewis, J. Biol. Chem., 1995; Keller et.al., Arch. Biochem. Biophys., 1996

Farnesol

Translation

Degradation

Degradation

Translation

Farnesol

d-limonene

Perillyl alcohol

Geranylgeraniol

Geranylgeranyl-PP

Monoterpenes

• Perillyl alcohol (POH)

mannose-6-phosphate/insulin growth factor II receptor TGF-β type I, II and III receptors in tumor cells

Mills et.al., Cancer Res., 1995

Male Fischer rats

diethylnitrosamine (DEN)1 month – induced liver tumors

Control (n=11) POH treated (n=10)

1% w/w POH – 1st week 2% w/w POH – 19 weeks

(Powdered diet)

Mean tumor mass 0.8g7.0g

Apoptotic index5-fold – large tumors10-fold – small tumors Low High

ANTI-ANGIOGENIC ROLE

• Anti-angiogenic function – Perillyl alcohol (POH)

• Rac – changes in cell morphology POH inhibits Rac interaction with membranes• p21 activated kinase – cell migration

• Angiogenic factorso VEGF – cell migration and cell survival POH decreases release of VEGF, increases Ang2 o Ang2 – neovascularization

Capillary formation

Blood vesselformation

Loutari et.al., J. Pharmacol. Exp. Ther., 2004; Connolly et.al., Mol. Biol. Cell, 2002

Monoterpenes

• d-limonene

• Mechanism - Apoptosis and decreased cell proliferation

Kaji et. al., Int. J. Cancer, 2001

Sprague-Dawley ratsN-nitrosomorpholine (NNM)8 weeks

Group 1 (n=20)Chow pellets

Group 2 (n=20)Chow pellets + 1% d-limonene

Group 3 (n=60)Chow pellets + 2% d-limonene

GST-P positive foci and lesions

Apoptotic index

Membraneassociatedp21 ras No significant effects

Monoterpenes

• Geraniol

o Results Tumor volumes in experimental rats was 20% that of control rats

o Mechanism Apoptosis

Yu et.al., J. Nutr., 1995

Morris 7777 hepatomas Male buffalo rats

Control (n=6) AIN-76A

Experimental (AIN-76A + geraniol 350μmol/d)

Diet – 14 days before and 42 days after tumor transplant

Diterpenes – Geranylgeraniol (GGOH)HuH-7 cells

GGOH (1-50μmol/L)

CAD ICAD

Nucleus

DNA fragmentation

Caspase-8

Caspase-3

Cytochrome-cCaspase-9

cleaves

Bcl-XL

Bid + Bax

- COOH

BH3 domain

apaf1

Takeda et. al., Jpn. J. Cancer Res., 2001; Enari et. al., Nature, 1998; Wang et. al., Genes &Dev., 1996; Luo et. al., Cell, 1998

Sesquiterpenes

• Farnesol

o Mechanism - FOH – inhibited HMG CoA reductase; GOH induced apoptosis

Ong et.al., Carcinogenesis, 2006

Male Wistar ratsInitiated – DEN, 2-AAF

Corn oil( n=12)0.25 ml/100g FOH (n=12)

25mg/100g

GOH (n=12)25mg/100g

Incidence + numberof nodules

Mean area of PNL’s

% liver sectionOccupied by PNL’s

Apoptosis

MIXED ISOPRENOIDSTocotrienols

• In vivo • In vitroC3H/He – spontaneous liver tumor

Experimental (n=14)T3 mixture (2.25mg/d)

γ, α, δ

Control (n=17)

7.6 tumors/mouse 1.4 tumors/mouse

Hep G2 cells

DMSO γ, δ isoforms (3 days)

Reduced cell viability

IC50 conc. – γ – 27.4µMδ – 9.6 µM

apoptosis

100 µM – 4 hours

conc. of δ isoforms72 hours

Control Experimental

S-phase arrest

Cell proliferation

Anti-carcinogenic effect

SYNTHETIC ISOPRENOIDS

• Contain a farnesol or geraniol molecule o More potent

Geranylgaranoic acid (GGA) 4,5 didehydro GGA

Mo and Elson, Exp. Biol. Med., 2004

SYNTHETIC ISOPRENOIDSHuH-7 cells

Geranylgeranoic acid 10 µM

Interleukin-1-β converting enzyme Cysteine protease precursor 32

APOPTOSIS

TGF-α + EGF

Shidoji et. al., Biochem. Biophys. Res. Commun., 1997; Enari et. al., Nature, 1996; Nakamura et. al., Biochem. Biophys. Res. Commun., 1996

SUMMARY

• Isoprenoids in liver cancero Liver tumor regression achieved chiefly by apoptosiso Decrease cell proliferation and tumor growth

Inhibition of protein isoprenylation Degradation of reductase

REFERENCES

• Lencioni, R., Caramella, D., Bartolozzi, C., Di Coscio, G. (1994) Long-term follow-up study of adenomatous hyperplasia in liver cirrhosis. Ital. J Gastroenterol. 26: 163-168

• Srivatanakul, P., Sriplung, H., Deerasamee, S. (2004) Epidemiology of Liver cancer: An overview. Asian Pacific J Cancer Prev. 5: 118-125

• El-Serag, H. B., Davilia, J. A., Peterson, N. J., McGlynn, K. A. (2003) The continuing increase in the incidence of hepatocellular carcinoma in the United States: An update Anal. Intern. Med. 139: 817-821

• Feitelson, M. A. (2004) c-myc overexpression in hepatocarcinogenesis. Hum. Pathol. 35: 1299-1302• Wang X. W., Forrester, K., Yeh, H., Feitelson, M. A., Gu, J., Harris, C. (1994) Hepatitis B virus X protein inhibits p53

sequence-specific DNA binding, transcriptional activity, and association with transcription factor ERCC3. Proc. Natl. Acad. Sci. 91: 2230-2234

• Moriya, K., Fujie, H., Shintani, Y. et. al. (1998) The core protein of hepatitis C virus induced hepatocellular carcinoma in transgenic mice. Nat. Med. 4: 1065-1067

• Moriya, K., Yotsuyanagi, H., Shintani, Y. et. al. (1997) Hepatitis C virus core protein induces hepatic steatosis in transgenic mice. J. Gen. Virol. 78: 1527-1531

• Ohata, K., Hamasaki, K., Toriyama, K. et. al. (2003) Hepatic steatosis is a risk factor for hepatocellular carcinoma in patients with chronic hepatitis C virus infection. Cancer 97: 3036-3043

• Wild, C. P., Jansen, L. A. M., Cova, L., Montesano, R. (1993) Molecular dosimetry of aflatoxin exposure: Contribution to understanding the multifactorial etiopathogenesis of primary hepatocellular carcinoma with particular reference to hepatitis B virus. Environ. Health Perspect. 99: 115-122

• Eaton, D. L., Gallagher, E. P. (1994) Mechanisms of aflatoxin carcinogenesis. Annu. Rev. Pharmacol. Toxicol. 34: 135-172

• Hussain, S. P., Aguilar, F., Amstad, P., Cerutti, P. (1994) Oxy-radical induced mutagenesis of hotspot codons 248 and 249 of the human p53 gene. Oncogene 9: 2277-2281

REFERENCES contd.

• Sell, S., Hunt, J. M., Dunsford, H. A., Chisari, F. V. (1991) Synergy between hepatitis B virus expression and chemical hepatocarcinogenesis in transgenic mice. Cancer Res. 51: 1278-1285

• Anthony, P.P., Vogel, C.L., Barker, L.F. (1973) Liver cell dysplasia: a premalignant condition. J. Clin. Path. 26: 217-223• Thorgeirsson, S. S., Grisham, J. W. (2002) Molecular pathogenesis of human hepatocellular carcinoma. Nat. Genet. 3:

339-346• Murukami, H., Sanderson, N.D., Nagy, P., Marino, P. A., Merlino, G., Thorgeirsson, S. S. (1993) Transgenic mouse model

for synergistic effects of nuclear oncogenes and growth factors in tumorogenesis: Interaction of c-myc and transforming growth factor α in hepatic oncogenesis. Cancer Res. 53: 1719-1723

• Sandgren, E. P., Quaife, C. J., Pinkert, C. A., Palmiter, R. D., Brinster, R. L. (1989) Oncogene-induced liver neoplasia in transgenic mice. Oncogene 4: 715-724

• Bhave, M. R., Wilson, M. J., Poirier, L. A. (1988) c-Ha-ras and c-Ki-ras gene hypomethylation in the livers and hepatomas of rats fed methyl-deficient diets. Carcinogenesis 9: 343-348

• Factor, V., Oliver, A. L., Panta, G. R., Thorgeirsson, S. S., Sonenshein, G. E., Arsura, M. (2001) Roles of Akt/PKB and IKK complex in constitutive induction of NF-кB in hepatocellular carcinomas of transforming growth factor α/c-myc in transgenic mice. Hepatology 34: 32-41

• Fynn, T. M., Reiss, M. (1993) Resistance to inhibition of cell growth by transforming growth factor β and its role in oncogenesis. Crit. Rev. Oncog. 4: 493-540

• Huang, S., He, J., Zhang, X. et.al. (2006) Activation of the hedgehog pathway in human hepatocellular carcinoma. Carcinogenesis 27: 1334-1340

• Tsuchihara, K., Hijikata, M., Fukuda, K., Kuroki, T., Yamamoto, N., Shimotohno, K. (1999) Hepatitis C virus core protein regulates cell growth and signal transduction pathway transmitting growth stimuli. Virology 72: 3060-3065

• Alexandrow, M. G., Moses, H. L. (1995) Transforming growth factor β and cell cycle regulation. Cancer Res. 55: 1452-1457

REFERENCES contd.

• Chiao, P. J., Na, R., Niu, J., Sclabas, G. M., Dong, Q., Curley, S. A. (2002) Role of Rel/NF-κB transcription factors in apoptosis of human hepatocellular carcinoma cells. Cancer 95: 1696-1705

• Arsura, M., Cavin, L. G. (2005) Nuclear factor- κB and liver carcinogenesis. Cancer Lett. 229: 157-169• Yancopoulos, G. D., Davis, S., Gale, N. W., Rudge, J. S., Wiegand, S. J., Holash, J. (2000) Vascular-specific growth

factors and blood vessel formation. Nature 407: 242-248• Lee, T. K., Poon, R. T. P., Yuen, A. P., Man, K., Yang, Z. F., Guan, X. Y., Fan, S. T. (2006) Rac activation is associated

with hepatocellular carcinoma metastasis by up-regulation of vascular endothelial growth factor expression. Clin. Cancer Res. 12: 5082-5089

• Johnson, R., Spiegelman, B., Hanahan, D., Wisdom, R. (1996) Cellular transformation and malignancy induced by ras require c-jun. Mol. Cell. Biol. 16: 4504-4511

• Eferl, R., Ricci, R., Kenner, L., Zenz, R., David, J., Rath, M., Wagner E. F. (2003) Liver tumor development: c-Jun antagonizes the proapoptotic activity of p53 Cell 112: 181-192.

• Eferl, R., Sibilia, M., Hillberg, F., Fuchsbichler, A. et. al. (1999) Functions of c-Jun in liver and heart development. J. Cell Biol. 145: 1049-1061

• Schreiber, M., Kolbus, A., Piu, F. et. al. (1999) Control of cell cycle progression by c-Jun is p53 dependent. Genes Dev. 13: 607-619

• Wu, X., Hong, L., Lan, Z., Yong, H. Huili, C. (1997) Changes of phosphotidylcholine-specific phospholipase C in hepatocarcinogenesis and in the proliferation and differentiation of rat liver cancer cells. Cell Biology International 21: 375-381

• Exton, J. H. (1994) Phosphotidylcholine breakdown and signal transduction. Biochem. Biophys. Acta. 1212: 26-24• Goldstein, J. L., Brown, M. D. (1990) Regulation of the mevalonate pathway. Nature (London) 343: 265-271• Goldstein, J. L., DeBose-Boyd, R. A., Brown, M. S. (2006) Protein sensors for membrane sterols. Cell 124: 35-46

REFERENCES contd.

• Siperstein, M. D., Fagan, V. M. (1964) Deletion of the cholesterol-negative feedback system in liver tumors. Cancer Res. 24: 1108-1115

• Vasudevan, S., Laconi, E., Khandelwal, M. et. al. (1994) Hypomethylation of β-hydroxy-β-methylglutaryl coenzyme A (HMG CoA) reductase gene in polyps and cancers of human colon. FASEB. J. 8: A647 (abs.)

• Kawata, S., Takaishi, K., Nagase, T., Ito, N., Matsuda, Y., Tamura, S., Matsuzawa, Y., Tarui, S. (1990) Increase in the active form of 3-Hydroxy-3-methylglutaryl coenzyme A reductase in human hepatocellular carcinoma: Possible mechanism for alteration of cholesterol biosynthesis. Cancer Res. 50: 3270-3273

• Cohen, L. H., Griffioen, M. (1988) Regulation of 3-hydroxy-3-methylglutaryl-CoA reductase mRNA contents in human hepatoma cell line Hep G2 by distinct classes of mevalonate-derived metabolites. Biochem. J. 255: 61-67

• Elson, C. E., Peffley, D. M., Hentosh, P., Mo, H. (1999) Isoprenoid-mediated inhibition of mevalonate synthesis: potential application to cancer. Proc. Soc. Exp. Biol. Med. 221:294-311.

• Elson, C. E., Yu, S. G. (1994) The chemoprevention of cancer by mevalonate-derived constituents of fruits and vegetables. J. Nutr. 124: 607-614

• Mo, H., Elson, C.E. (2006) Isoprenoids and novel inhibitors of mevalonate pathway activities. Nutritional Oncology, 2nd ed., Academic Press, p. 629-644

• Packham, G., Cleaveland, J. L. (1994) Ornithine decarboxylase is a mediator of c-myc induced apoptosis. Mol. Cell. Biol. 14: 5741-5747

• Clark, S. (2006) Perillyl alcohol induces c-myc dependent apoptosis in Bcr/Abl-transformed leukemia cells. Oncology 70: 13-18

• Mills, J. J., Chari, R. S., Boyer, I. J., Gould, M. N., Jirtle, R. L. (1995) Induction of apoptosis in liver tumors by the monoterpene Perillyl alcohol. Cancer Res. 55: 979-983

• Kaji, I., Tatsuta, M., Iishi, H., Baba, M., Inoue, A., Kasugai, H. (2001) Inhibition by d-limonene of experimental hepatocarcinogenesis in Sprague-Dawley rats does not involve p21ras plasma membrane association. Int. J. Cancer 93: 441-444

REFERENCES contd.

• Yu, S. G., Hilderbrandt, L. A., Elson, C. E. (1995) Geraniol, an inhibitor of mevalonate biosynthesis, suppresses the growth of hepatomas and melanomas transplanted to rats and mice. J. Nutr. 125: 2763-2767

• Masuda, Y., Nakaya, M., Nakajo, S., Nakaya, K. (1997) Geranylgeraniol potently induces caspase-3-like activity during apoptosis in human leukemia U937 cells. Biochem. Biophys. Res. Commun. 234: 641-645

• Takeda, Y., Nakao, K., Nakata, K. et. al. (2001) Geranylgeraniol, an intermediate product in mevalonate pathway, induces apoptotic cell death in human hepatoma cells: Death receptor-independent activation of caspase-8 with down-regulation of Bcl-xL Expression. Jpn. J. Cancer Res. 92: 918-925

• Enari, M., Sakahira, H., Yokoyama, H., Okawa, K., Iwamatsu, A., Nagata, S. (1998) A caspase-activated DNase that degrades DNA during apoptosis, and its inhibitor ICAD. Nature 391: 43-50

• Wang, K., Yin, X. M., Chao, D. T., Milliman, C. L., Korsmeyer, S. J. (1996) BID: a novel BH3 domain-only death agonist. Genes & Dev. 10: 2859-2869

• Luo, X., Budihardjo, I., Zou, H., Slaughter, C., Wang, X. (1998) Bid, a Bcl2 interacting protein, mediates cytochrome c release from mitochondria in response to activation of cell surface death receptors. Cell 94: 481-490

• Crowell, P. L., Chang, R. R., Ren, Z., Elson, C. E., Gould, M. N. (1991) Selective inhibition of isoprenylation of 21-26-kDa proteins by the anticarcinogen d-limonene and its metabolites. J. Biol. Chem. 266: 17679-17685

• Hohl, R. J., Lewis, K. (1995) Differential effects of monoterpenes and lovastatin on RAS processing. J. Biol. Chem. 270: 17508-17512

• Keller, R. K., Zhao, Z., Chambers, C., Ness, G. C. (1996) Farnesol is not the nonsterol regulator mediating degradation of HMG-CoA reductase in rat liver. Arch. Biochem. Biophys. 328: 324-330

• Ong, T. P., Heidor, R., Conti. A., Dagli, M. L. Z., Moreno, F. S. (2006) Farnesol and geraniol chemopreventive activities during the initial phases of hepatocarcinogenesis involve similar actions on cell proliferation and DNA damage, but distinct actions on apoptosis, plasma cholesterol and HMG CoA reductase. Carcinogenesis 27: 1194-1203

REFERENCES contd.

• Miquel, K., Pradines, A., Tercè, F., Selmi, S., Favre, G. (1998) Competitive inhibition of choline phosphotransferase by geranylgeraniol and farnesol inhibits phosphatidylcholine synthesis and induces apoptosis in human lung adenocarcinoma A549 cells. J. Biol. Chem. 273: 26179-26186

• Loutari, H., Hatziapostolou, M., Skouridou, V., Papadimitriou, E., Roussos, C., Kolisis, F. N., Papapetropoulos, A. (2004) Perillyl alcohol is an angiogenesis inhibitor. J. Pharmacol. Exp. Ther. 311: 568-575

• Connolly, J. O., Simpson, N., Hewlett, L., Hall, A. (2002) Rac regulates endothelial morphogenesis and capillary assembly. Mol. Biol. Cell 13: 2474-2485

• Wada, S., Satomi, Y., Murakoshi, M., Noguchi, N., Yoshikawa, T., Nishino, H. (2005) Tumor suppressive effects of tocotrienol in vivo and in vitro. Cancer Lett. 229: 181-191.

• Shidoji, Y., Nakamura, N., Moriwaki, H. Muto, Y. (1997) Rapid loss in the mitochondrial membrane potential during geranylgeranoic acid-induced apoptosis. Biochem. Biophys. Res. Commun. 230: 58-63

• Nakamura, N., Shidoji, Y., Moriwaki, H., Muto, Y. (1996) Apoptosis in human hepatoma cell line induced by 4,5-Didehydro geranylgeranoic Acid (Acyclic Retinoid) via down-regulation of transforming growth factor-α. Biochem. Biophys. Res. Commun. 219: 100-104

• Enari, M., Talanian, R. V., Wrong, W. W., Nagata, S. (1996) Sequential activation of ICE-like and CPP32-like proteases during Fas-mediated apoptosis. Nature 380: 723-726