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Davis M.E.,California Institute of Technology | Zuckerman J.E.,California Institute of Technology | Choi C.H.J.,California Institute of Technology | Seligson D.,Jonsson Comprehensive Cancer Center | And 7 more authors.
Nature | Year: 2010

Therapeutics that are designed to engage RNA interference (RNAi) pathways have the potential to provide new, major ways of imparting therapy to patients. Long, double-stranded RNAs were first shown to mediate RNAi in Caenorhabditis elegans, and the potential use of RNAi for human therapy has been demonstrated by the finding that small interfering RNAs (siRNAs; approximately 21-base-pair double-stranded RNA) can elicit RNAi in mammalian cells without producing an interferon response. We are at present conducting the first in-human phase I clinical trial involving the systemic administration of siRNA to patients with solid cancers using a targeted, nanoparticle delivery system. Here we provide evidence of inducing an RNAi mechanism of action in a human from the delivered siRNA. Tumour biopsies from melanoma patients obtained after treatment show the presence of intracellularly localized nanoparticles in amounts that correlate with dose levels of the nanoparticles administered (this is, to our knowledge, a first for systemically delivered nanoparticles of any kind). Furthermore, a reduction was found in both the specific messenger RNA (M2 subunit of ribonucleotide reductase (RRM2)) and the protein (RRM2) levels when compared to pre-dosing tissue. Most notably, we detect the presence of an mRNA fragment that demonstrates that siRNA-mediated mRNA cleavage occurs specifically at the site predicted for an RNAi mechanism from a patient who received the highest dose of the nanoparticles. Together, these data demonstrate that siRNA administered systemically to a human can produce a specific gene inhibition (reduction in mRNA and protein) by an RNAi mechanism of action. © 2010 Macmillan Publishers Limited. All rights reserved.

Satsangi A.,University of Texas Health Science Center at San Antonio | Satsangi A.,University of Texas at San Antonio | Roy S.S.,University of Texas Health Science Center at San Antonio | Satsangi R.K.,Rann Research Corporation | And 4 more authors.
Biomaterials | Year: 2015

Breast cancer is the leading cause of cancer deaths among women. Paclitaxel (PTX), an important breast cancer medicine, exhibits reduced bioavailability and therapeutic index due to high hydrophobicity and indiscriminate cytotoxicity. PTX encapsulation in one-level active targeting overcomes such barriers, but enhances toxicity to normal tissues with cancer-similar expression profiles. This research attempted to overcome this challenge by increasing selectivity of cancer cell targeting while maintaining an ability to overcome traditional pharmacological barriers. Thus, a multi-core, multi-targeting construct for tumor specific delivery of PTX was fabricated with (i) an inner-core prodrug targeting the cancer-overexpressed cathepsin B through a cathepsin B-cleavable tetrapeptide that conjugates PTX to a poly(amidoamine) dendrimer, and (ii) the encapsulation of this prodrug (PGD) in an outer core of a RES-evading, folate receptor (FR)-targeting liposome. Compared to traditional FR-targeting PTX liposomes, this sequentially active-targeted dendrosome demonstrated better prodrug retention, an increased cytotoxicity to cancer cells (latter being true when FR and cathepsin B activities were both at moderate-to-high levels) and higher tumor reduction. This research may eventually evolve a product platform with reduced systemic toxicity inherent with traditional chemotherapy and localized toxicity inherent to single-target nanoplatforms, thereby allowing for better tolerance of higher therapeutic load in advanced disease states. © 2015 Elsevier Ltd.

Tolcher A.,START South Texas Accelerated Research Therapeutics LLC | Goldman J.,University of California at Los Angeles | Patnaik A.,START South Texas Accelerated Research Therapeutics LLC | Papadopoulos K.P.,START South Texas Accelerated Research Therapeutics LLC | And 13 more authors.
European Journal of Cancer | Year: 2014

Background LY2584702 tosylate (hereafter referred to as LY2584702) is a potent, highly selective adenosine triphosphate (ATP) competitive inhibitor against p70 S6 kinase, a downstream component of the phosphatidylinositol-3- kinase signalling pathway which regulates cell proliferation and survival. LY2584702 exhibited anti-tumour activity in preclinical analysis. Methods Patients with advanced solid tumours were treated with LY2584702 orally on a 28-day cycle until the criteria for maximum tolerated dose (MTD) were met. Skin biopsies were collected for pharmacodynamic analysis, and levels of phospho-S6 protein were examined. The primary objective was to determine a phase II dose and schedule with secondary objectives of observing safety and tolerability. Dose escalation was based upon Common Terminology Criteria for Adverse Events Version 3.0. Results Thirty-four patients were enrolled onto this phase I study and treated with LY2584702 on a QD (once-daily) or BID (twice-daily) dosing schedule. Part A dose escalation (n = 22) began with 300 mg BID (n = 2). Due to toxicity, this was scaled back to doses of 25 mg (n = 3), 50 mg (n = 8), 100 mg (n = 3), and 200 mg (n = 6) QD. Part B dose escalation (n = 12) included 50 mg (n = 3), 75 mg (n = 3), and 100 mg (n = 6) BID. Seven patients experienced dose-limiting toxicity (DLT). All DLTs were Grade 3 and included vomiting, increased lipase, nausea, hypophosphataemia, fatigue and pancreatitis. Conclusion The MTD was determined to be 75 mg BID or 100 mg QD. No responses were observed at these levels. Pharmacokinetic analysis revealed substantial variability in exposure and determined that LY2584702 treatment was not dose proportional with increasing dose. © 2014 Published by Elsevier Ltd.

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