A Pilot Surrogate End Point Biomarker Trial of Perillyl Alcohol in Breast Neoplasia

Simultaneous measurement of perillyl alcohol and its metabolite perillic acid in plasma and lung after inhalational administration in Wistar rats

The inhalational administration of drugs is a practical and non-invasive approach with the potential to reduce side effects and with a quick onset of therapeutic activity. Perillyl alcohol (POH) is a monoterpene with antitumor activity that currently is undergoing clinical evaluation as an inhalational anticancer agent. A detection method was developed that will be applicable to pharmacokinetic studies of not only POH, but also its longer-lived main metabolite, perillic acid (PA), in lung tissue and plasma after inhalational delivery. The anticancer activity of POH was investigated in vitro with the use of various lung cancer cell lines. Toxicity was established by a standard MTT assay, and apoptosis markers were analyzed by Western blot. For the detection of POH and PA in lungs and plasma, albino Wistar rats were used that were exposed to POH inhalation. Tissues were subjected to chromatographic separation on an Agilent Zorbax Eclipse XDB C₁₈ column, followed by detection of absorption in the ultraviolet (UV) range. In vitro, POH exerted cytotoxic activity against six different lung tumor cell lines, and apoptotic cell death was indicated by induction of active caspase 3 and cleavage of poly (ADP-ribose) polymerase 1 (PARP1). These results demonstrate that inhalational delivery of POH results in effective biodistribution and metabolism of POH in the systemic circulation. In addition, our study introduces a simple, rapid HPLC-UV method with high accuracy for simultaneous detection of POH and its metabolite PA in plasma, and for sensitive detection of PA in lung tissue, which should prove useful for applications in clinical studies.

Window-of-Opportunity Study of Valproic Acid in Breast Cancer Testing a Gene Expression Biomarker

Purpose

The anticancer activity of valproic acid (VPA) is attributed to the inhibition of histone deacetylase. We previously published the genomically derived sensitivity signature for VPA (GDSS-VPA), a gene expression biomarker that predicts breast cancer sensitivity to VPA in vitro and in vivo. We conducted a window-of-opportunity study that examined the tolerability of VPA and the ability of the GDSS-VPA to predict biologic changes in breast tumors after treatment with VPA.

Patients and Methods

Eligible women had untreated breast cancer with breast tumors larger than 1.5 cm. After a biopsy, women were given VPA for 7 to 12 days, increasing from 30 mg/kg/d orally divided into two doses per day to a maximum of 50 mg/kg/d. After VPA treatment, serum VPA level was measured and then breast surgery or biopsy was performed. Tumor proliferation was assessed by using Ki-67 immunohistochemistry. Histone acetylation of peripheral blood mononuclear cells was assessed by Western blot. Dynamic contrast-enhanced magnetic resonance imaging scans were performed before and after VPA treatment.

Results

Thirty women were evaluable. The median age was 54 years (range, 31-73 years). Fifty-two percent of women tolerated VPA at 50 mg/kg/d, but 10% missed more than two doses as a result of adverse events. Grade 3 adverse events included vomiting and diarrhea (one patient) and fatigue (one patient). The end serum VPA level correlated with a change in histone acetylation of peripheral blood mononuclear cells (ρ = 0.451; P = .024). Fifty percent of women (three of six) with triple-negative breast cancer had a Ki-67 reduction of at least 10% compared with 17% of other women. Women whose tumors had higher GDSS-VPA were more likely to have a Ki-67 decrease of at least 10% (area under the curve, 0.66).

Conclusion

VPA was well tolerated and there was a significant correlation between serum VPA levels and histone acetylation. VPA treatment caused a decrease in proliferation of breast tumors. The genomic biomarker correlated with decreased proliferation. Inhibition of histone deacetylase is a valid strategy for drug development in triple-negative breast cancer using gene expression biomarkers.

Neoadjuvant Chemotherapy: What Are the Benefits for the Patient and for the Investigator?

Neoadjuvant chemotherapy has several appealing potential benefits compared with classic adjuvant chemotherapy. Of these, the only proven benefit is to facilitate the surgical approach, either by converting an inoperable cancer to one that is operable, or by converting a patient who is felt to be a candidate for mastectomy to one who might be treated successfully with breast conserving therapy. Randomized trials comparing neoadjuvant chemotherapy with postoperative chemotherapy have failed to demonstrate prolongation of overall survival. The benefits of monitoring apparent response during neoadjuvant chemotherapy have not been proven. Conduct of phase II drug development trials in the neoadjuvant setting may be advantageous compared with performing such trials in the metastatic setting. However, such trials raise concerns that are not unavoidable but need to be addressed.

Predictors of willingness to participate in window-of-opportunity breast trials

OBJECTIVE

We conducted a pilot survey to evaluate breast cancer patients' willingness to participate in a preoperative chemoprevention (ie, window-of-opportunity) study. Design A 27-question written survey was developed and administered to participants. Setting A breast cancer specialty clinic at the University of Wisconsin Hospital and Clinics. Participants 30 adult patients with newly diagnosed operable breast cancer participated after signing informed consent.

METHODS

A convenience sample of 30 participants was recruited from July 2005 through January 2006. Participants were administered the survey in clinic. Univariate ordinal logistic regression models were used to identify predictors of willingness to participate in window-of-opportunity trials.

RESULTS

Overall, 26.7% of respondents were willing to participate in a research trial between the time of breast cancer diagnosis and surgery. Univariate ordinal logistic regression models identified that women with a prior history of breast cancer (P=0.060), prior research participation (P=0.006), more education (P=0.034), and self-reported breast cancer knowledge (P=0.043) were more willing to participate. On average, women preferred to have surgery 7 days (range 1-14) after their diagnosis, but the actual average wait time between diagnostic biopsy and surgery was 37.5 days (standard deviation = 23.4 days).

CONCLUSION

There is ample time before breast surgery to conduct preoperative window-of-opportunity trials. Interventions aimed at expanding patients' breast cancer knowledge may improve accrual to window-of-opportunity studies.

Breast cancer prevention trials: large and small trials

Breast cancer is the most common cancer among women in the United States, with 192,870 new cases and 40,170 deaths due to this disease estimated to have occurred 2009. An emphasis on prevention has been increasing in view of a persisting high incidence of disease. Seventy percent of breast cancers are estrogen receptor (ER)-positive, and are therefore presumed to be hormone-responsive and potentially treatable or preventable by anti-estrogenic agents. To date, the large, phase III randomized controlled breast cancer prevention trials have tested and are testing only hormonal drugs designed to antagonize the carcinogenic effect of endogenous estrogen; these agents are either selective estrogen receptor modulators (SERMs) or aromatase inhibitors (AIs). The SERMs, tamoxifen and raloxifene, have been shown in these large trials to reduce the risk of ER-positive breast cancers; prevention trials of AIs are ongoing. Interest is now focusing on developing agents with a broader spectrum of preventive activity, particularly with regard to ER-negative subtypes of breast cancer. A number of phase I and II trials using tissue-derived surrogate endpoint biomarkers (SEBs) as outcomes have been implemented. These smaller trials address prevention not only of ER-negative but also ER-positive breast cancers, since approximately 50% of the latter have been shown to be resistant to the estrogen-targeting drugs used in the large trials. Issues of importance in these smaller trials include choice of agent, selection of appropriate trial participants, trial design, method of access to breast tissue in women without cancer, selection and monitoring of SEBs, and monitoring of drug toxicity.

Chemo-resistant protein expression pattern of glioblastoma cells (A172) to perillyl alcohol

Glioblastoma multiform (GBM) is by far the most malignant glioma. We have introduced a new treatment for GBMs that comprises the inhalation of a naturally occurring terpene with chemotherapeutic properties known as perillyl alcohol (POH). Clinical trial results on recurrent GBM patients showed that POH extends the average life by more than eight months, temporarily slows tumor growth, and in some cases even decreases tumor size. After approximately seven months, the tumor continues to grow and leads to a dismal prognosis. To investigate how these tumors become resistant to POH, we generated an A172 human glioblastoma cell culture tolerant to 0.06 mM of POH (A172r). We used Multidimensional Protein Identification Technology (MudPIT) to compare the protein expression profile of A172r cells to the established glioblastoma A172 cell line. Our results include a list of identified proteins unique to either the resistant or the nonresistant cell line. These proteins are related to cellular growth, negative apoptosis regulation, Ras pathway, and other key cellular functions that could be connected to the underlying mechanisms of resistance.

Dynamic proteomic overview of glioblastoma cells (A172) exposed to perillyl alcohol

Perillyl alcohol (POH) is a naturally occurring terpene and a promising chemotherapeutic agent for glioblastoma multiform; yet, little is known about its molecular effects. Here we present results of a semi-quantitative proteomic analysis of A172 cells exposed to POH for different time-periods (1', 10', 30', 60', 4h, and 24h). The analysis identified more than 4000 proteins; which were clustered using PatternLab for proteomics and then linked to Ras signaling, tissue homeostasis, induction of apoptosis, metallopeptidase activity, and ubiquitin-protein ligase activity. Our results make available one of the most complete protein repositories for the A172. Moreover, we detected the phosphorylation of GSK3beta (Glycogen synthase kinase) and the inhibition of ERK's (extracellular signal regulated kinase) phosphorylation after 10', which suggests a new mechanism of POH's activation for apoptosis.

Molecular mechanisms involved in farnesol-induced apoptosis

The isoprenoid alcohol farnesol is an effective inducer of cell cycle arrest and apoptosis in a variety of carcinoma cell types. In addition, farnesol has been reported to inhibit tumorigenesis in several animal models suggesting that it functions as a chemopreventative and anti-tumor agent in vivo. A number of different biochemical and cellular processes have been implicated in the growth-inhibitory and apoptosis-inducing effects of farnesol. These include regulation of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase and CTP:phosphocholine cytidylyltransferase alpha (CCTalpha), rate-limiting enzymes in the mevalonate pathway and phosphatidylcholine biosynthesis, respectively, and the generation of reactive oxygen species. In some cell types the action of farnesol is mediated through nuclear receptors, including activation of farnesoid X receptor (FXR) and peroxisome proliferator-activated receptors (PPARs). Recent studies have revealed that induction of endoplasmic reticulum (ER) stress and the subsequent activation of the unfolded protein response (UPR) play a critical role in the induction of apoptosis by farnesol in lung carcinoma cells. This induction was found to be dependent on the activation of the MEK1/2-ERK1/2 pathway. In addition, farnesol induces activation of the NF-kappaB signaling pathway and a number of NF-kappaB target genes. Optimal activation of NF-kappaB was reported to depend on the phosphorylation of p65/RelA by the MEK1/2-MSK1 signaling pathway. In a number of cells farnesol-induced apoptosis was found to be linked to activation of the apoptosome. This review provides an overview of the biochemical and cellular processes regulated by farnesol in relationship to its growth-inhibitory, apoptosis-promoting, and anti-tumor effects.

Phytochemicals as potential chemopreventive and chemotherapeutic agents in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the fifth commonest malignancy worldwide and the incidence is rising. Surgery, including transplantation resection, is currently the most effective treatment for HCC; however, recurrence rates are high and long-term survival is poor. Identifying novel chemopreventive and chemotherapeutic agents and targeting them to patients at high risk of developing HCC or following curative treatment may go some way towards improving prognosis. This review examines current knowledge regarding the chemopreventive and chemotherapeutic potential of phytochemicals in heptocarcinogenesis. Both in-vitro and animal studies demonstrate that several phytochemicals, including curcumin, resveratrol, green tea catechins, oltipraz and silibinin, possess promising chemopreventive and chemotherapeutic properties. Despite this, very few clinical trials have been performed. Problems regarding validation of biomarkers, agent delivery, side effects and patient selection are barriers that need to be overcome to determine the potential of such agents in clinical practice.

Research Issues Affecting Preoperative Systemic Therapy for Operable Breast Cancer

Preoperative systemic therapy (PST) in operable breast cancer allows a small increase in breast conservation rates and has significant potential as a research platform. PST offers the ability to discern treatment effect in vivo, and may allow smaller trials targeting specific breast cancer subtypes and making more efficient use of resources. Early observations of a specific outcome of interest in individual patient subgroups may improve the design of larger definitive randomized adjuvant trials using survival as a main outcome. PST offers the potential for therapeutic adjustments midcourse, which assumes the existence of validated intermediate end points and effective alternative therapies. This article reviews critical research issues affecting the design of PST trials, including the appropriate selection of trial end points and markers for long-term outcome, baseline marker expression as a predictor of response, and statistical considerations using novel trial designs. Key issues regarding optimal tumor subtype selection for individual trials, novel approaches using nontherapeutic window trial designs, and ethical and advocacy considerations are also discussed. PST requires an experienced and cohesive multidisciplinary team for it to fulfill its potential in both research and clinical care.

Phase II trial of daily oral perillyl alcohol (NSC 641066) in treatment-refractory metastatic breast cancer

PURPOSE

Perillyl alcohol (POH) is a naturally occurring lipid with preclinical activity against mammary carcinomas. We conducted a phase II multi-institutional study of oral POH administered four times daily in women with advanced treatment-refractory breast cancer.

METHODS

Eligible women were treated with POH four times daily at 1,200-1,500 mg m(-2) dose(-1) on a 28-day cycle. Patients tolerating 1,200 mg m(-2) day(-1) four times daily after one cycle were dose-escalated to 1,500 mg/m(2). The primary endpoint was 1-year freedom-from-progression (FFP) rate. Secondary endpoints were response rate, tolerability and correlative evaluations.

RESULTS

Twenty-nine cycles of POH were administered to 14 women. Three patients were dose-escalated to 1,500 mg/m(2). Grade 1 and grade 2 gastrointestinal effects and fatigue were predominant toxicities. Of seven patients receiving up to one cycle, three stopped therapy due to intolerance. Only two patients received more than two cycles, with disease stabilization of 3 and 8 months. Thirteen patients were evaluable for response. One-year FFP rate was zero. No objective responses were seen. The median time to progression was 35 days (95% CI, 29-123 days). Median overall survival was 389 days (95% CI, 202-776 days). Pharmacokinetic parameters were similar to previous investigations. The ability to correlate plasma TGF-beta1 levels with outcome was limited by lack of clinical benefit and inter- and intra-patient variability.

CONCLUSIONS

Enrollment was suspended short of planned accrual because of lack of response and poor tolerance to POH. This regimen does not appear to provide benefit in advanced treatment-refractory breast carcinoma.

Perillyl alcohol and genistein differentially regulate PKB/Akt and 4E-BP1 phosphorylation as well as eIF4E/eIF4G interactions in human tumor cells

Previously we demonstrated that secondary products of plant mevalonate metabolism called isoprenoids attenuate 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA translational efficiency and cause tumor cell death. Here we compared effects of "pure" isoprenoids (perillyl alcohol and gamma-tocotrienol) and a "mixed" isoprenoid-genistein-on the PKB/Akt/mTOR pathway that controls mRNA translation and m(7)GpppX eIF4F cap binding complex formation. Effects were cell- and isoprenoid-specific. Perillyl alcohol and genistein suppressed 4E-BP1(Ser65) phosphorylation in prostate tumor cell lines, DU145 and PC-3, and in Caco2 adenocarcinoma cells. Suppressive effects were similar to or greater than that observed with a PI3 kinase inhibitor or rapamycin, an mTOR inhibitor. 4E-BP1(Thr37) phosphorylation was reduced by perillyl alcohol and genistein in DU145, but not in PC-3. Conversely, perillyl alcohol but not genistein decreased 4E-BP1(Thr37) phosphorylation in Caco2. PKB/Akt activation via Ser473 phosphorylation was enhanced in DU145 by perillyl alcohol and in PC-3 by gamma-tocotrienol, but was suppressed by genistein. Importantly, perillyl alcohol disrupted interactions between eIF4E and eIF4G, key components of eIF4F (m(7)GpppX) cap binding complex. These results demonstrate that "pure" isoprenoids and genistein differentially impact cap-dependent translation in tumor cell lines.

Mastic Oil from Pistacia lentiscus var. chia Inhibits Growth and Survival of Human K562 Leukemia Cells and Attenuates Angiogenesis

Mastic oil from Pistacia lentiscus var. chia, a natural plant extract traditionally used as a food additive, has been extensively studied for its antimicrobial activity attributed to the combination of its bioactive components. One of them, perillyl alcohol (POH), displays tumor chemopreventive, chemotherapeutic, and antiangiogenic properties. We investigated whether mastic oil would also suppress tumor cell growth and angiogenesis. We observed that mastic oil concentration and time dependently exerted an antiproliferative and proapoptotic effect on K562 human leukemia cells and inhibited the release of vascular endothelial growth factor (VEGF) from K562 and B16 mouse melanoma cells. Moreover, mastic oil caused a concentration-dependent inhibition of endothelial cell (EC) proliferation without affecting cell survival and a significant decrease of microvessel formation both in vitro and in vivo. Investigation of underlying mechanism(s) demonstrated that mastic oil reduced 1) in K562 cells the activation of extracellular signal-regulated kinases 1/2 (Erk1/2) known to control leukemia cell proliferation, survival, and VEGF secretion and 2) in EC the activation of RhoA, an essential regulator of neovessel organization. Overall, our results underscore that mastic oil, through its multiple effects on malignant cells and ECs, may be a useful natural dietary supplement for cancer prevention.

Heterogeneity of cellular proliferation within transitional cell carcinoma: correlation of protein kinase C alpha/betaI expression and activity

A total of 18 histological samples containing both transitional cell carcinoma (TCC) and normal urothelial epithelium were analyzed for protein kinase C (PKC)-alpha and -betaI expression, and for their phosphorylated substrates. The results showed an increased expression of PKC-alpha in 13 out of 18 samples and -betaI in 11 out of 18 TCC samples when compared with normal urothelium. In addition, 11 out of 18 of the TCC tumors displayed heterogeneous expression of the PKC isoenzymes, with different levels of immunosignal in different areas of the tumor. Within the same sample, areas of highest PKC isoenzyme expression also showed highest classical PKC activity, as estimated by immunodetection of phosphorylated forms of PKC substrates. The areas of highest expression of PKC-alpha and/or -betaI isoenzymes showed also the highest number of cells positive for Ki67, an indicator of proliferation. Immunofluorescence and Western blotting demonstrated that in cultured TCC cells, PKC-alpha was located in the cytoplasm, whereas PKC-betaI was located primarily in the nucleus as a 65-kDa fragment and in the cytoplasm as a full-size 79-kDa protein. Our results indicate that increased expression of PKC-alpha and -betaI leads to increased total classical PKC kinase activity and suggest that increased activity of the isoenzymes plays a role in accelerated growth of TCC. Furthermore, these results suggest that even in carcinoma tissue, PKC expression and activity are under strict control.

A pilot study to establish a clinical model to perform phase II studies of breast cancer chemopreventive agents in women at high risk with biomarkers as surrogate endpoints for activity

PURPOSE

Use of surrogate end point biomarkers in phase II trials may help select agents that appear to have activity and might be evaluated in future phase III definitive trials of breast cancer prevention. We performed a pilot clinical trial to establish the logistics for a clinical model to perform phase II studies of breast cancer chemopreventive agents in women at high risk with novel imaging techniques and candidate surrogate end point biomarkers for activity. We chose tamoxifen to establish proof of principal with a known effective agent.

EXPERIMENTAL DESIGN

Women at a high risk of developing a new breast cancer and for whom tamoxifen was recommended were eligible. The women underwent baseline and 3 and 6 months mammogram and magnetic resonance imaging (MRI) of one breast to identify areas of water-like intensity (epithelial) and to determine the changes over time and MRI-directed core breast biopsies of these areas for surrogate end point biomarkers analysis.

RESULTS

From August 1999 to March 2001, 26 women underwent baseline imaging and core biopsies. Sixteen women took tamoxifen and 10 chose not to. Overall, 79% of the samples contained glandular tissue evaluable for histology, but only 66% of the samples were evaluable for marker analysis. Only 12 patients had specimens with glandular tissue sufficient for marker analysis both at baseline and in at least one follow-up. Because of the small number of women with matched samples, marker analysis was not informative.

CONCLUSIONS

This study shows the feasibility of obtaining serial core breast biopsies from women at a high risk of developing a new breast cancer. Patient participation in this model is satisfactory, and such a model may provide indication of drug activity. MRI-directed biopsy did not provide a high yield of evaluable samples, and additional work on adequate collection of epithelial tissue for surrogate end point biomarker analysis is thus necessary.