|Abstracts of Current Research:
- Cooperation between Antioxidants and 1,25-Dihydroxyvitamin D3 in Induction of Leukemia HL60 Cell Differentiation through the JNK/AP-1/Egr-1 Pathway: Vitamin D derivatives have demonstrated anti-cancer activity, but their clinical use is precluded by hypercalcemia. Previously, we found that carnosic acid potentiates differentiation of human leukemia cells induced by low concentrations of 1alpha,25-dihydroxyvitamin D3 (1,25D3). This was associated with a synergistic antioxidant effect. In this study, we investigated whether there is a common mechanism whereby antioxidants potentiate monocytic differentiation. All antioxidants tested (carnosic acid, curcumin, silibinin, and ebselen) enhanced differentiation-related cell cycle arrest induced by a low (1 nM) concentration of 1,25D3. Addition of antioxidants to 1,25D3 activated the JNK pathway as indicated by increased phosphorylation of c-jun and ATF-2, although each compound alone had a minimal effect. Antioxidants also enhanced the1,25D3-induced AP-1 DNA binding and transactivation ability. In addition, expression of Egr-1 and c-fos was increased. The potentiation of differentiation by antioxidants was inhibited by JNK inhibitor SP600125 and dominant negative JNK 1/2 construct, and Egr-1 and c-fos expression was proportionally decreased, suggesting that JNK pathway regulates these transcription factors. Thus, JNK-AP-1 pathway has an important role in the potentiation of 1,25D3-induced differentiation by antioxidants, and regulates expression of Egr-1 and c-fos. Combinations of antioxidants with 1,25D3 should be further evaluated for use in cancer chemoprevention and therapy.
- Synergistic antileukemic effects of differentiation agents and plant antioxidants: role of nuclear receptors for retinoids and vitamin D: 1,25-dihydroxyvitamin D3 (1,25D) and all-trans retinoic acid (ATRA) are powerful differentiation agents, but have marked toxicity at therapeutic doses. Treatment of myeloid leukemia cell lines (HL60, U937 and NB4) with very low concentrations of ATRA (0.1-1.0 nM) or 1,25D (1 nM) combined with plant polyphenols (carnosic acid from rosemary and silibinin from milk thistle) resulted in a strong synergistic induction of differentiation and growth inhibition. This was accompanied by an augmented expression of nuclear receptors for retinoids (RAR and RXR) and 1,25D (VDR). In transiently transfected U937 cells and MCF-7 breast cancer cells, the polyphenol-ATRA combinations synergistically induced transactivation of retinoic acid response element (DR5) originated from RARbeta2 promoter. Similarly, polyphenol-1,25D combinations induced a synergistic transactivation of vitamin D response element (VDRE). The APL cell line (NB4) bears a characteristic t(15;17) chromosomal translocation resulting in the expression of PML-RARalpha fusion protein, which is known to suppress RARbeta induction. In our experiments, combinations of carnosic acid and ATRA considerably reduced the levels of PML-RARalpha, which was associated with reorganization of nuclear bodies. These data suggest an important role of nuclear receptors, particularly RARbeta, in the polyphenol-enhanced myeloid leukemia cell differentiation.
- Cooperative anticancer effects of vitamin D compounds and plant polyphenols on WEHI-3B D- murine leukemia cells in vitro and in vivo: We determined the effects of plant polyphenols (carnosic acid from rosemary and silibinin from milk thistle) and 1,25-dihydroxyvitamin D3 (1,25D) or its low-calcemic analogs (Ro25-4020 and Ro27-5646), alone and in combination, on differentiation and proliferation of WEHI-3B D- murine myelomonocytic leukemia cells. Furthermore, the anticancer effects of the analogs, rosemary extract (RosEx) and silibinin, alone and in combinations were investigated in syngeneic Balb/c mice inoculated with WEHI-3B D- cells. Carnosic acid and silibinin inhibited the growth of WEHI-3B D- cells in culture but did not significantly induce cell differentiation. However, the combinations of either polyphenol with very low concentrations of 1,25D or analogs (0.05-1.0 nM) induced strong synergistic differentiating and antiproliferative effects. Balb/c mice inoculated i.p. or i.v. with WEHI-3B D- cells developed abdominal tumors or systemic leukemia, respectively. Injection of analogs (3 times a week) combined with constant treatment with RosEx mixed with food resulted in synergistic increase in the animal survival, a delay in tumor formation and a reduction in tumor size. These effects were not accompanied with general toxicity in treated animals. Our results may suggest novel protocols of differentiation therapy of myeloid leukemia using plant polyphenols and their combinations with differentiation inducers.
- Shabtay, A., Sharabani, H., Barvish, Z., Kafka, M., Amichay, D., Levy, Y., Sharoni, Y., Uskokovic, M.R., Studzinski, G.P. & Danilenko, M. . Synergistic Antileukemic Activity of Carnosic Acid-Rich Rosemary Extract and 19-nor Gemini Vitamin D Analog in a Mouse Model of Systemic Acute Myeloid Leukemia. Oncology 75: 203-214 (2008)
- Kim, S.H., Danilenko, M. & Kim, T.S.. Differential enhancement of leukemia cell differentiation without elevation of intracellular calcium by plant-derived sesquiterpene lactone compounds. British J. Pharmacol. 155: 814-825 (2008)
- Groysman, N., Orynbayeva, Z., Katz, M., Kolusheva, S., Khanin, M., Danilenko, M. & Jelinek, R.. Membrane processes and biophysical characterization of living cells decorated with chromatic polydiacetylene vesicles. Biochim Biophys Acta: Biomembranes. 1778: 1335-1343 (2008)
- Hirsch, K., Atzmon, A., Danilenko, M., Levy, J. & Sharoni, Y.. Lycopene and other carotenoids inhibit estrogenic activity of 17beta-estradiol and genistein in cancer cells. Breast Cancer Res and Treatment. 104: 221-230 (2008)
- Ozpolat, B., Akar, U., Steiner, M., Zorrilla-Calancha, I., Tirado-Gomez, M., Colburn, N., Danilenko M., Kornblau S. & Lopez-Berestein, G.. Programmed cell death-4 tumor suppressor protein contributes to retinoic acid-induced terminal granulocytic differentiation of human myeloid leukemia cells. Mol Cancer Res. 5: 95-108 (2007)
- Zhang, J., Posner, G.H., Danilenko, M. & Studzinski, G.P.. Differentiation-inducing potency of the seco-steroid JK-1624F2-2 can be increased by combination with an antioxidant and a p38 MAPK inhibitor which upregulates the JNK pathway. J. Steroid Biochem & Mol Biol. 105: 140-149 (2007)
- Nahum, A., Zeller, L., Danilenko, M., Prall, O. W. J., Watts, C. K. W., Sutherland, R. L., Levy, J., & Sharoni, Y.. Lycopene inhibition of IGF-induced cancer cell growth depends on the level of cyclin D1. Eur J Nutr. 45: 275-282 (2006)
- Sharabani, H., Izumchenko, E., Wang, Q., Kreinin, R., Steiner, M., Barvish, Z., Kafka, M., Sharoni, Y., Levy, J., Uskokovic, M., Studzinski, G. P., & Danilenko, M.. Cooperative Antitumor Effects of Vitamin D3 Derivatives and Rosemary Preparations in a Mouse Model of Myeloid Leukemia. Int J Cancer 118: 3012-3021 (2006)
- Ben-Dor, A., Steiner, M., Gheber, L., Danilenko, M., Doubi, N., Linnewiel, K., Zick, A., Sharoni, Y., Levy, J.. Carotenoids activate the antioxidant response element transcription system Mol Cancer Ther 4177-186: 177-186 (2005)
- Wang, Q., Salman, H., Danilenko, M., Studzinski, G.P.. Cooperation between antioxidants and 1,25-dihydroxyvitamin D3 in induction of leukemia HL60 cell differentiation through the JNK/AP-1/Egr-1 pathway. J Cell Physiol March 29: DOI 10.1002/jcp.203 (2005)
- Danilenko, M. and Studzinski, G. P.. Enhancement by other compounds of the anti-cancer activity of vitamin D3 and its analogs Exp. Cell Res 298: 339-358 (2004)
- Danilenko, M., Wang, Q., Wang, X., Levy, J., Sharoni, Y. and Studzinski, G. P.. Carnosic acid potentiates the antioxidant and prodifferentiation effects of 1,25-dihydroxyvitamin D3 in leukemia cells, but does not promote elevation of basal levels of intracellular calcium Cancer Res 63: 1325-1332 (2003)
- Danilenko, M., Wang, X., and Studzinski, G. P. . Carnosic acid and promotion of monocytic differentiation of HL60-G cells initiated by other agents J Natl Cancer Inst. 93: 1224-1233 (2001)