Greg Reed

Dopamine alleviation of diaphragm contractile dysfunction and reduction of deoxyribonucleic acid damage in rats.

BACKGROUND Weaning difficulties from mechanical ventilation are associated with diaphragm fatigue and reduced respiratory muscle endurance capacity. Often the work of breathing is increased during the weaning process as a result of inspiratory resistance loading (IRL). IRL produces increased free radical formation that contributes to deoxyribonucleic acid (DNA) damage. The purpose of this study was to determine whether dopamine reduced nuclei DNA damage when the work of breathing was increased. We hypothesized that the administration of low-dose dopamine (2 microg/kg/min) during IRL decreases myonuclei DNA damage associated with free radical formation. METHODS In this in vivo study, 30 male Sprague-Dawley rats were divided into three groups: (1) the sham group receiving no IRL or no intravenous fluids, (2) IRL with administration intravenous saline, and (3) IRL with intravenous low-dose dopamine (2 microg/kg/min). All rats from the same breed and similar colonies were purchased from one laboratory facility to ensure homogeneity. The animals were anesthetized and tracheotomized, and an ultrasonic sensor was attached to the right hemidiaphragm to measure diaphragm shortening. Diaphragm fatigue was produced by IRL. Dopamine (2 microg/kg/min) was infused intravenously before and during loading. The diaphragms were excised, and myonuclei DNA damage was measured using the fluorescent dyes ethidium bromide and acridine orange and comet analyses as indices of free radical injury. RESULTS In rats receiving saline, diaphragm shortening decreased by 37% after 45 minutes of IRL (P = .002) compared with baseline. In contrast, rats infused with dopamine exhibited a 31% increase in diaphragm shortening after 45 minutes of IRL (P = .037). With the use of differential dye uptake, in the saline group 59% of the nuclei were apoptotic, and 18% were necrotic. However, in the dopamine group there was significantly less apoptotic nuclei (16%, P < .001) and necrotic nuclei (7%, P = .005). Myonuclei DNA damage, measured by comet analyses, was associated with tail length and tail olive moment, which were 37% and 60% greater, respectively, in the saline group than in the dopamine group (P < .05). CONCLUSION These data support the hypothesis that low-dose dopamine during IRL reduced myonuclei DNA damage as measured by the fluorescent dyes and comet analysis. In addition, diaphragm fatigue was prevented by the administration of dopamine during IRL.

Abstract 5882: Bench-to-bedside translation of ciclopirox prodrug for the treatment of non-muscle invasive and muscle-invasive bladder cancer

Ciclopirox (CPX) is contained in a number of FDA-approved topical antifungal drug products as the free acid and olamine salt. CPX possesses anticancer activity in a number of in vitro and in vivo preclinical models. Its clinical utility is limited as an oral anticancer agent, however. The oral bioavailability of CPX is quite low due to extensive first pass effect. The poor water solubility of CPX and its olamine salt prevent formulation as an injectable drug product. Thirdly, dose-limiting gastrointestinal toxicities were observed following four times daily oral dosing of CPX in patients with advanced hematologic malignancies. Ciclopirox Prodrug (CPX-POM), in contrast, has demonstrated excellent bioavailability via injectable routes of administration. Here we describe the preclinical characterization of CPX-POM, a novel anticancer agent being developed for the treatment of non-muscle invasive (NMIBC) and muscle invasive (MIBC) bladder cancer. Following IV, SQ and IP administration to mice, CPX-POM is rapidly and completely metabolized to CPX in blood via circulating phosphatases. CPX and its major, inactive glucuronide metabolite are extensively eliminated in urine. At well-tolerated doses, steady-state urine concentrations of CPX exceed in vitro IC50 values in mice by 15-30 fold. CPX inhibited cell proliferation, colony formation, and bladdosphere formation in vitro in T24 (NMIBC) and 253JBV (MIBC) human cell lines in both concentration- and time-dependent manners with IC50 values of 2-4 µM. CPX exposure increased the percentage of NMIBC and MIBC cells arrested at the S and G0/G1 phases, and induced cell death. CPX exposure significantly reduced expression of genes at the mRNA level involved in cancer stem cell signaling pathways including Notch, Wnt, and Hedgehog. CPX was shown to inhibit bladder cancer cell growth in vitro by inhibiting the Notch 1 signaling pathway. The validated N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) chemical carcinogen mouse model of bladder cancer was employed to establish in vivo preclinical proof of principle for CPX-POM. Over the once-daily IP dose range of 25-200 mg/kg, CPX-POM treatment resulted in significant decreases in bladder weight, a clear migration to lower stage tumors, dose-dependent reduction in Ki67 and PCNA staining, as well as a reduction in PCNA-expressing cells. All CPX-POM doses were well tolerated with no evidence of toxicity to the urinary tract based on blinded pathologic evaluation. There were also dose-dependent decreases in Notch 1, Presenilin 1, and Hey 1 in bladder cancer tissues obtained from CPX-POM treated animals. Tumor response was similar, in vivo, following once-daily and three-times weekly CPX-POM administration. CPX-POM has received FDA clearance to proceed to Phase I, and is currently being evaluated in a first-in-human trial in patients with advanced solid tumors. Citation Format: Scott J. Weir, Partha Ranjarajan, Robyn Wood, Karl Schorno, Prabhu Ramamoorthy, Lian Rajweski, Kathy Heppert, Michael J. McKenna, William McCulloch, Greg A. Reed, Amanda Brinker, Michael J. Baltezor, Roy A. Jensen, John A. Taylor, Shrikant Anant. Bench-to-bedside translation of ciclopirox prodrug for the treatment of non-muscle invasive and muscle-invasive bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5882.

536PA PHASE I TRIAL OF IRINOTECAN (IRI) AND BUPARLISIB IN PREVIOUSLY TREATED PATIENTS (PTS) WITH METASTATIC COLORECTAL CANCER (MCRC): FINAL RESULTS

ABSTRACT Aim: Buparlisib is an oral pan-class PI3K inhibitor. A phase I trial established the safety and recommended dose of single agent Buparlisib, and promising preliminary anti-tumor activity was seen. It is currently being studied in combinatorial trials in several different malignancies. The primary objective of this phase I trial was to identify the maximum tolerated dose (MTD) for Iri plus Buparlisib in patients with previously treated mCRC, with or without previous exposure to Iri. The secondary objectives were to determine the PK of each drug alone and in combination, to determine clinical response to the combination, and to correlate biomarkers of PI3K signaling with clinical response. Methods: A conventional 3 + 3 dose titration scheme was used. Iri was administered intravenously every 14 days and Buparlisib given orally daily. The first dose of Iri was administered on cycle1 day1, with Buparlisib starting 24 hours after the first dose of Iri. Pts were assessed for safety and toxicities every cycle (q14 days). Results: Twenty patients were enrolled: 14 were evaluable for DLT: 3 in cohort 0 (Iri 120 mg/m2 + Buparlisib 50 mg/d), 7 in cohort 1 (Iri 150 mg/m2 + Buparlisib 50 mg/d), 4 in cohort 2 (Iri 150 mg/m2 + Buparlisib 80 mg/d). The most common adverse events (all grades) were nausea, vomiting, diarrhea, fatigue, hyperglycemia, and transaminitis. The MTD was Iri 150 mg/m2 + Buparlisib 50 mg/d. One dose limiting toxicity (DLT), grade 2 genital mucositis, was observed in a male pt in cohort 1. In cohort 2, one pt had DLT of grade 3 diarrhea and another had DLT with asymptomatic grade 3 hyponatremia. One pt in cohort 1 experienced grade 2 delirium and a pt in cohort 2 had grade 3 psychosis. Of the 4 pts who received 4 cycles of therapy 2 had stable and 2 had progressive disease. No objective responses were observed. PK data and molecular correlates will be presented in the meeting. Conclusions: This first human trial established that Buparlisib (50 mg qd) and Iri (150 mg/m2 q14d) are tolerable in combination. The efficacy of this regimen will need to be tested in future studies. Disclosure: J.C. Baranda: Research Funding from Novartis. All other authors have declared no conflicts of interest.

Abstract 5397: Crocetin, a carotenoid compound derived from Saffron, enhances antitumor effects of paclitaxol and cisplatin in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States and no significant treatment is at present available. Although there are an increasing number of therapeutic options available for patients with advanced disease, their efficacy is time limited and non-curative. Presently approximately 50-60% of cancer patients in the United States utilize therapies derived from plants, herbs, flowers, or nutrients (complementary and alternative medicine [CAM]), exclusively or concurrently with their traditional therapies such as chemotherapy or radiation therapy. One such CAM therapy is “crocetin”, a carotenoid compound isolated from the saffron plant. Recent studies demonstrated that crocetin has a significant antitumorigenic effect in both in vitro and in vivo on pancreatic cancer. Two conventional chemotherapeutic agents, paclitaxol (a microtubule-targeted agent) and cisplatin (a platinum based anticancer drug binds to DNA), have been demonstrated significant reduction of growth and proliferation in pancreatic cancer. Therefore, the aim of the series of experiments was to determine whether crocetin enhances paclitaxol or cisplatin induced proliferation in pancreatic cancer. MIA-PaCa-2 and BxPC3 cells were treated with crocetin and paclitaxol or cisplatin together at different doses and a proliferation assay was utilized using Click-it Edu flurorometric assay. Paclitaxol or cisplatin alone at higher doses (50-100nM) inhibited proliferation in both MIA PaCa2 and BxPC3 cells but crocetin (200μM) in combination of paclitaxol or cisplatin showed significant additive effect even at lower doses (10 and 25nM) of paclitaxol or cisplatin. The combinational effect is more pronounced in BxPC3 cells. Paclitaxol or cisplatin alone at higher doses (50-100nM) stimulated apoptosis using Deadend flurorometric TUNEL apoptosis assay in MIA PaCa2 and BxPC3 cells and apoptosis is more pronounced at lower doses in combination with crocetin. This study indicated that crocetin in combination with lower doses of paclitaxol or cisplatin inhibited proliferation and stimulated apoptosis in pancreatic cancer. The antitumorigenic effect is more pronounced in BxPC3 cells and paclitaxol is more effective than cisplatin at lower doses in combination with crocetin. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5397.