Kirk S. Culotta

l-Arginine Consumption by Macrophages Modulates the Expression of CD3ζ Chain in T Lymphocytes

l-Arginine plays a central role in the normal function of several organs including the immune system. It is metabolized in macrophages by inducible nitric oxide synthase to produce nitric oxide, important in the cytotoxic mechanisms, and by arginase I (ASE I) and arginase II (ASE II) to synthesize l-ornithine and urea, the first being the precursor for the production of polyamines needed for cell proliferation. l-Arginine availability can modulate T cell function. Human T cells stimulated and cultured in the absence of l-arginine lose the expression of the TCR ζ-chain (CD3ζ) and have an impaired proliferation and a decreased cytokine production. The aim of this work was to test whether activated macrophages could modulate extracellular levels of l-arginine and alter T cell function, and to determine which metabolic pathway was responsible for this event. The results show that macrophages stimulated with IL-4 + IL-13 up-regulate ASE I and cationic amino acid transporter 2B, causing a rapid reduction of extracellular levels of l-arginine and inducing decreased expression of CD3ζ and diminished proliferation in normal T lymphocytes. Competitive inhibitors of ASE I or the addition of excess l-arginine lead to the re-expression of CD3ζ and recovery of T cell proliferation. In contrast, inducible nitric oxide synthase or ASE II failed to significantly reduce the extracellular levels of l-arginine and modulate CD3ζ expression. These results may provide new insights into the mechanisms leading to T cell dysfunction and the down-regulation of CD3ζ in cancer and chronic infectious diseases.

Phase II Randomized, Placebo-Controlled Trial of Green Tea Extract in Patients with High-Risk Oral Premalignant Lesions

Epidemiologic and preclinical data support the oral cancer prevention potential of green tea extract (GTE). We randomly assigned patients with high-risk oral premalignant lesions (OPL) to receive GTE at 500, 750, or 1,000 mg/m2 or placebo thrice daily for 12 weeks, evaluating biomarkers in baseline and 12-week biopsies. The OPL clinical response rate was higher in all GTE arms (n = 28; 50%) versus placebo (n = 11; 18.2%; P = 0.09) but did not reach statistical significance. However, the two higher-dose GTE arms [58.8% (750 and 1,000 mg/m2), 36.4% (500 mg/m2), and 18.2% (placebo); P = 0.03] had higher responses, suggesting a dose-response effect. GTE treatment also improved histology (21.4% versus 9.1%; P = 0.65), although not statistically significant. GTE was well tolerated, although higher doses increased insomnia/nervousness but produced no grade 4 toxicity. Higher mean baseline stromal vascular endothelial growth factor (VEGF) correlated with a clinical (P = 0.04) but not histologic response. Baseline scores of other biomarkers (epithelial VEGF, p53, Ki-67, cyclin D1, and p16 promoter methylation) were not associated with a response or survival. Baseline p16 promoter methylation (n = 5) was associated with a shorter cancer-free survival. Stromal VEGF and cyclin D1 expression were downregulated in clinically responsive GTE patients and upregulated in nonresponsive patients at 12 weeks (versus at baseline). An extended (median, 27.5 months) follow-up showed a median time to oral cancer of 46.4 months. GTE may suppress OPLs, in part through reducing angiogenic stimulus (stromal VEGF). Higher doses of GTE may improve short-term (12-week) OPL outcome. The present results support longer-term clinical testing of GTE for oral cancer prevention.

Decreased Expression of CD3ζ and Nuclear Transcription Factor κB in Patients with Pulmonary Tuberculosis: Potential Mechanisms and Reversibility with Treatment

BACKGROUND The protective immune response against Mycobacterium tuberculosis relies both on antigen-presenting cells and on T lymphocytes. In patients with different forms of tuberculosis, varying degrees of T cell function--ranging from positive delayed-type hypersensitivity, in asymptomatic infected healthy individuals, to the absence of the response, in patients with miliary or pulmonary tuberculosis (PTB)--have been reported. The decreased expression of CD3zeta reported in T cells from patients with either cancer or leprosy has provided possible explanations for the altered immune response observed in these diseases. METHODS The present study aimed to compare the expression of CD3zeta , nuclear transcription factor- kappa B (NF- kappa B), arginase activity, and cytokine production in 20 patients with PTB, in 20 tuberculin-positive asymptomatic subjects, and in 14 tuberculin-negative control subjects. RESULTS Compared with those in tuberculin (purified protein derivative)-negative control subjects, peripheral-blood T lymphocytes from patients with active PTB had significantly (P < .001) decreased expression of CD3zeta and absence of the p65/p50 heterodimer of NF- kappa B. These alterations were reversed only in patients who responded to treatment. Also reported here for the first time is that the presence of arginase activity in peripheral-blood mononuclear-cell lysates of patients with PTB parallels high production of interleukin-10. CONCLUSIONS The presence of arginase could, in part, explain the decreased expression of CD3zeta . These findings provide a novel mechanism that may explain the T cell dysfunction observed in patients with PTB.

Phase 2 study of dasatinib in the treatment of head and neck squamous cell carcinoma

Treatment options for patients with advanced head and neck squamous cell carcinoma (HNSCC) are scarce. This phase 2 study was conducted to evaluate the safety, tolerability, pharmacokinetics, and efficacy of dasatinib in this setting.

Phase I Study of the Combination of Sorafenib and Temsirolimus in Patients with Metastatic Melanoma

Purpose: This phase I clinical trial was conducted to determine the safety, efficacy, and molecular effects of sorafenib with temsirolimus in patients with advanced melanoma. Patients and Methods: Patients with stage IV or unresectable or recurrent stage III melanoma and Eastern Cooperative Oncology Group performance status of 0 to 1 were eligible. Sorafenib was given orally once or twice daily and temsirolimus was given i.v. weekly, both starting on day 1, with a 4-week cycle. Responses were assessed every 2 cycles per Response Evaluation Criteria in Solid Tumors criteria. Consenting patients with accessible tumors underwent optional tumor biopsies before treatment and after the second infusion of temsirolimus. Tumor biopsies were analyzed for activating mutations in BRAF and NRAS, and for expression of P-extracellular signal-regulated kinase (P-ERK) and P-S6 proteins. Results: A total of 25 patients were accrued to the study. The maximum tolerated doses were sorafenib 400 mg every morning and 200 mg every evening and temsirolimus 25 mg i.v. weekly. Dose-limiting toxicities included thrombocytopenia, hand-foot syndrome, serum transaminase elevation, and hypertriglyceridemia. There were no complete or partial responses with the combination; 10 patients achieved stabilization of disease as their best response. The median progression-free survival was 2.1 months. Matching pretreatment and day 15 tumor biopsies showed marked inhibition of P-S6 with treatment in 3 of 4 evaluable patients, but minimal inhibition of P-ERK. Conclusions: Combination therapy with sorafenib and temsirolimus resulted in significant toxicity at higher dose levels, failed to achieve any clinical responses in genetically unselected patient population, and did not inhibit P-ERK. Clin Cancer Res; 18(4); 1120–8. ©2012 AACR.

A Phase I/II Study of the mTOR Inhibitor Everolimus in Combination with HyperCVAD Chemotherapy in Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia

Purpose: Previous studies suggest a potential therapeutic role for mTOR inhibition in lymphoid malignancies. This single-center phase I/II study was designed to test the safety and efficacy of the mTOR inhibitor everolimus in combination with HyperCVAD chemotherapy in relapsed/refractory acute lymphoblastic leukemia (ALL). Experimental Design: Twenty-four patients were treated; 15 received everolimus 5 mg/day and 9 received 10 mg/day with HyperCVAD. Results: The median age of patients was 25 years (range, 11–64) and median number of prior treatments was 2 (range, 1–7). Grade 3 mucositis was the dose-limiting toxicity and the maximum tolerated everolimus dose was 5 mg/day. Responses included complete remission (CR) in 6 patients (25%), CR without platelet recovery (CRp) in 1 (4%), and CR without recovery of counts (CRi) in 1 (4%), for an overall response rate of 33%. In addition, partial response (PR) was noted in 2 patients (8%). Seven of 11 patients treated in first salvage achieved CR/CRp (64%). The median OS was 29 weeks for patients in first salvage versus 15 weeks for patients in second salvage and beyond (P ≤ 0.001). A response was noted in 5 of 10 (50%) heavily pretreated T-ALL patients (median of 4 prior salvage regimens). Everolimus significantly inhibited phosphorylation of S6RP, but this did not correlate with response. No significant decreases in p4EBP1 and pAkt levels were noted. Responders had higher everolimus dose-adjusted area under the curve (P = 0.025) and lower clearance (P = 0.025) than nonresponders. Conclusions: The combination of HyperCVAD and everolimus is well tolerated and moderately effective in relapsed ALL, specifically T-ALL. Clin Cancer Res; 21(12); 2704–14. ©2015 AACR.

Busulfan and metronidazole: An often forgotten but significant drug interaction

Objective: To report the case of a clinically significant drug interaction between intravenous busulfan and oral metronidazole observed through busulfan therapeutic drug monitoring (TDM). Case Summary: A 7-year-old boy with a history of myelodysplasia that progressed to acute myeloid leukemia received busulfan with therapeutic drug monitoring (TDM), clofarabine, and thiotepa as a pretransplant conditioning regimen for a cord blood transplant. The patient received metronidazole the day after a busulfan test dose of 0.5 mg/kg was administered. On the day of the first busulfan therapeutic dose, TDM was performed and the clearance of busulfan was significantly decreased by 46%. After 2 doses of busulfan therapy, the course area under the curve was exceeded, requiring discontinuation of busulfan. Metronidazole is not known to affect glutathione or the glutathione S-transferase AI (GSTA1) enzyme system or cytochrome P450 (CYP) 3A4. Discussion: Busulfan is a bifunctional alkylating agent widely used in pretransplant conditioning regimens in patients undergoing stem cell transplantation for hematologic malignancies. Busulfan metabolism is best described by hepatic conjugation to glutathione by GSTA1, although some CYP-dependent pathways have been described. Currently there is 1 publication describing the drug interaction between oral busulfan and oral metronidazole, in which concomitant use of metronidazole resulted in higher busulfan trough concentrations and higher risk of veno-occlusive disease. Our case represents a possible drug interaction based on the Horn Drug Interaction Probability Scale. Conclusions: Though the mechanistic basis for this interaction is unknown, the risks and benefits of using metronidazole during and in close proximity to busulfan should be carefully considered and therapeutic alternatives to metronidazole should be used when appropriate.

Dual inhibition of the vascular endothelial growth factor pathway: A phase 1 trial evaluating bevacizumab and AZD2171 (cediranib) in patients with advanced solid tumors

The current study was conducted to evaluate the safety and biological activity of dual inhibition of the vascular endothelial growth factor (VEGF) pathway with combined bevacizumab and cediranib (a VEGF receptor tyrosine kinase inhibitor).

Physical and chemical stability of high-dose ifosfamide and mesna for prolonged 14-day continuous infusion.

Purpose Ifosfamide plus mesna have been used recently in a high-dose regimen that allows this chemotherapy to be given to outpatients with less toxicity over 14 days using a portable pump. However, there is a need for published stability information. The aim of this study was to investigate the physicochemical stability of ifosfamide with mesna in normal saline at room temperature over a prolonged period of 14 days. Methods Infusion solutions of 1:1 ifosfamide and mesna at final concentrations of 10, 20 and 30 mg/mL were prepared with 0.9% sodium chloride in PVC bags. Solutions were stored at room temperature. Concentrations of ifosfamide and mesna were measured at 0 and 1, 3, 7 and 14 days using a stability-indicating reversed phase high-performance liquid chromatography (HPLC) assay with ultraviolet detection. Results Ifosfamide and mesna were both physicochemically stable (>94%) for 14 days in all tested infusion solutions (10, 20 and 30 mg/mL). Conclusions Our stability data indicate that ifosfamide and mesna (1:1) combination can be administered as a prolonged continuous infusion with portable pump in an outpatient setting without replacement of the infusion bag. We suggest 20 mg/mL as a reasonable concentration for infusion rates of about 2-4 cc/hr over prolonged periods of time.

Phase I Trial of Hepatic Arterial Infusion of Nanoparticle Albumin–Bound Paclitaxel: Toxicity, Pharmacokinetics, and Activity

Because liver involvement in patients with metastatic cancer has limited options and poor outcomes, we conducted a phase I study to determine the safety, activity, and pharmacokinetic characteristics of hepatic arterial infusion of nanoparticle albumin–bound paclitaxel (HAI nab-paclitaxel). Cohorts of three patients having predominant hepatic metastases received HAI nab-paclitaxel at three dose levels (180, 220, and 260 mg/m2, respectively) infused for more than 1 hour every 3 weeks (3 + 3 design). Some patients participated in comparative pharmacokinetic studies (i.v. vs. HAI), receiving their first course i.v., to determine peak concentrations and effect of first-pass hepatic extraction compared with subsequent courses administered by HAI. The highest dose level was expanded to determine the safety and activity of HAI nab-paclitaxel. Thirty-eight patients were treated. There were no dose-limiting toxicities at doses up to 260 mg/m2. Common adverse events included alopecia, fatigue, myelosuppresion, nausea, and vomiting. Three patients had stable disease for 4 or more months and 2 patients (1 of 12 with breast cancer and 1 of 1 with cervical cancer) achieved a partial response lasting for 5 and 15 months, respectively. Peak concentrations were lower (∼50%) with greater hepatic extraction of drug (∼42%) following HAI than i.v. infusion based on area under the curve comparison of drug exposure. HAI nab-paclitaxel showed partial hepatic extraction. At doses 260 mg/m2 or less given for 1 hour every 3 weeks, the treatment was well-tolerated and showed activity in advanced cancer patients with predominant liver metastases. Mol Cancer Ther; 10(7); 1300–7. ©2011 AACR.