Phenethyl isothiocyanate (PEITC) and sulforaphane (SF) exhibit tumor preventive activity in lung, prostate, breast and colon cancers. Our objective was to examine the effect of these two isothiocyanates on estrogen receptor-related genes, and genes related to apoptosis and cell cycle in the estrogen-dependent breast cancer cell line MCF7 and in normal human epithelial breast (HME) cells. We treated cells with 0.3 μM or 3.0 μM concentrations of PEITC or SF. In HME cells, gene expression was significantly altered for 23 genes by PEITC at a concentration of 0.3 μM and 4 genes at 3.0 μM. SF altered the expression of 16 genes at a concentration of 0.3 μM and 2 genes at 3.0 μM. In HME cells, genes altered by both PEITC and SF exhibited changes in gene expression that were similar in extent as well as direction of change. In MCF-7 cells, PEITC did not produce any significant changes in the gene expression at both treatment levels. SF produced significant changes in 7 genes, but only at the higher treatment level of 3.0 μM. Normal mammary cells exhibited more changes in the expression of estrogen receptor related genes than did breast cancer cells, and significantly these changes occurred predominantly at the low concentration of 0.3 μM, a concentration achievable by dietary input of isothiocyanates. Novel findings were the upregulation of the pro-apoptotic gene BAD and estrogen receptor beta gene in normal human mammary cells. These gene alterations observed, along with upregulation of tumor suppressors p21 and p27, may provide a protective effect to mammary cells against breast cancer.

Isothiocyanates, a class of anti-cancer agents, are derived from cruciferous vegetables such as broccoli, cabbage and watercress, and have demonstrated chemopreventive activity in a number of cancer models and epidemiologic studies. Due to public interest in cancer prevention and alternative therapies in cancer, the consumption of herbal supplements and vegetables containing these compounds is widespread and increasing. Isothiocyanates interact with ATP-binding cassette (ABC) efflux transporters such as P-glycoprotein, MRP1, MRP2 and BCRP, and may influence the pharmacokinetics of substrates of these transporters. This review discusses the pharmacokinetic properties of isothiocyanates, their interactions with ABC transporters, and presents some data describing the potential for isothiocyanate-mediated diet–drug interactions.

Dietary intake of isothiocyanates (ITC) has been associated with reduced cancer risk. The dietary phenethyl ITC (PEITC) has previously been shown to decrease the phosphorylation of the translation regulator 4E binding protein 1 (4E-BP1). Decreased 4E-BP1 phosphorylation has been linked to the inhibition of cancer cell survival and decreased activity of the transcription factor hypoxia-inducible factor (HIF), a key positive regulator of angiogenesis, and may therefore contribute to potential anti-cancer effects of PEITC. In the present study, we have investigated the in vitro and in vivo effects of watercress, which is a rich source of PEITC. We first demonstrated that, similar to PEITC, crude watercress extracts inhibited cancer cell growth and HIF activity in vitro. To examine the effects of dietary intake of watercress, we obtained plasma and peripheral blood mononuclear cells following the ingestion of an 80 g portion of watercress from healthy participants who had previously been treated for breast cancer. Analysis of PEITC in plasma samples from nine participants demonstrated a mean maximum plasma concentration of 297 nM following the ingestion of watercress. Flow cytometric analysis of 4E-BP1 phosphorylation in peripheral blood cells from four participants demonstrated significantly reduced 4E-BP1 phosphorylation at 6 and 8 h following the ingestion of watercress. Although further investigations with larger numbers of participants are required to confirm these findings, this pilot study suggests that flow cytometry may be a suitable approach to measure changes in 4E-BP1 phosphorylation following the ingestion of watercress, and that dietary intake of watercress may be sufficient to modulate this potential anti-cancer pathway.

Phenethyl isothiocyanate (PEITC) is a constituent of cruciferous vegetables that has demonstrated cancer preventive activity in a number of cancer models including lung, prostate, and breast cancer. Our objective was to examine the effects of the oral administration of PEITC for 7 days on the hepatic expression of genes important in drug metabolism and toxicity in Sprague Dawley rats. The liver is the major site for the metabolism of various xenobiotics and carcinogens, and determining the effects of PEITC on the gene expression of hepatic enzymes may provide insight into mechanisms underlying the cancer preventive activity of PEITC. Using a microarray containing 282 genes, we observed that PEITC significantly up-regulated UDP-glucuronosyltransferase UGT1A6 and strongly down-regulated nicotinamide N-methyltransferase (NNMT). We also confirmed the down-regulation of NNMT by real-time quantitative RT-PCR. NNMT was recently shown to be elevated in the serum of tumor bearing patients with pancreatic, lung, and colorectal cancer, and may be involved in cell migration. Other genes that were significantly up-regulated were the drug metabolizing enzyme cyp2b15, the anti-apoptotic gene bcl2l2, and the stress regulators Gadd45b, Dnajb9, Dnajb5 and Hspb1. Our results indicate new targets that may be important in the mechanisms of the anticancer effects of PEITC. Of particular significance was the down-regulation of NNMT which may represent a new target for the treatment of a variety of cancers.

Purpose: Previous reports demonstrate that chloropyramine has anti-tumor efficacy as a single agent, and in combination with cytotoxic agents like doxorubicin through modulation of the FAK-VEGFR-3 pathway. Since limited information is available about the pharmacokinetics of chloropyramine, we investigated the pharmacokinetics and tissue distribution of the drug following a single intraperitoneal (IP) injection. Methods: Female CD-1 mice received a single 50mg/kg dose of chloropyramine; plasma and tissue samples were collected at serial timepoints of 0.5, 1.0, 2.0, 4.0, and 6.0 hours. The tissues included brain, heart, spleen, liver, lung, muscle, and sternum. Each timepoint contained three mice. Chloropyramine concentrations were determined in both plasma and tissues, using a validated LC-MS/MS. Assay was validated with an LLOQ of 0.25ng/ml with the calibration curve ranging from 0.25-100ng/ml (3.42-12.4%CV). Noncompartmental PK analysis was performed using WinNonlin (Pharsight, Version 5.3). Pharmacokinetic parameters including: Maximal concentration (Cmax), terminal elimination half life (T1/2), area under the curve (AUC0-6hr), apparent clearance (Cl/F), apparent volume of distribution (Vd/F), and partition coefficients (Kp). Results: Following IP injection, chloropyramine followed either a mono- or bi-exponential decay in both plasma and tissues. Chloropyramine is cleared from plasma and all tissues within 12hr; thus chloropyramine does not exhibit a great potential for accumulation. Cmax was achieved within 1.0 hour for plasma and all tissues. Chloropyramine distributes well into various tissues such as the spleen, liver, lung, kidney, brain, and heart. The highest level of chloropyramine was achieved in lung tissue with a mean (sd) Cmax concentrations of 41.6 (11.6) μg/ml, respectively. In contrast, the mean Cmax in plasma was approximately 0.5 μg/ml; much less compared to tissues. The mean T1/2 was 0.83 (0.19) hr. The lungs exhibited the highest total tissue penetration of chloropyramine, representing a mean AUC of 51.3 μg-hr/g. The least total exposure was in muscle, with a mean AUC of 8.5 μg-hr/g. The apparent CL/F from plasma was 28.5 L/hr/kg while it was 0.9 L/hr/kg for lung tissue. Conclusions: These results illustrate the wide tissue distribution of chloropyramine, despite of the short plasma half-life. In addition, these results are of great importance because it provides supportive evidence of the tissue levels that will lead to anti-tumor efficacy through inhibition of FAK and VEGFR-3. Thus, evaluation of plasma and tissue concentrations of the drug elucidates the pharmacokinetics of this compound in an effort to identify target tissues into which it has a high degree of penetration to maximize antitumor efficacy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4257. doi:10.1158/1538-7445.AM2011-4257