Darren R. Carpizo

Allele-specific p53 mutant reactivation.

Rescuing the function of mutant p53 protein is an attractive cancer therapeutic strategy. Using the National Cancer Institutes anticancer drug screen data, we identified two compounds from the thiosemicarbazone family that manifest increased growth inhibitory activity in mutant p53 cells, particularly for the p53(R175) mutant. Mechanistic studies reveal that NSC319726 restores WT structure and function to the p53(R175) mutant. This compound kills p53(R172H) knockin mice with extensive apoptosis and inhibits xenograft tumor growth in a 175-allele-specific mutant p53-dependent manner. This activity depends upon the zinc ion chelating properties of the compound as well as redox changes. These data identify NSC319726 as a p53(R175) mutant reactivator and as a lead compound for p53-targeted drug development.

Pancreatic cancer modeling using retrograde viral vector delivery and in vivo CRISPR/Cas9-mediated somatic genome editing

Pancreatic ductal adenocarcinoma (PDAC) is a genomically diverse, prevalent, and almost invariably fatal malignancy. Although conventional genetically engineered mouse models of human PDAC have been instrumental in understanding pancreatic cancer development, these models are much too labor-intensive, expensive, and slow to perform the extensive molecular analyses needed to adequately understand this disease. Here we demonstrate that retrograde pancreatic ductal injection of either adenoviral-Cre or lentiviral-Cre vectors allows titratable initiation of pancreatic neoplasias that progress into invasive and metastatic PDAC. To enable in vivo CRISPR/Cas9-mediated gene inactivation in the pancreas, we generated a Cre-regulated Cas9 allele and lentiviral vectors that express Cre and a single-guide RNA. CRISPR-mediated targeting of Lkb1 in combination with oncogenic Kras expression led to selection for inactivating genomic alterations, absence of Lkb1 protein, and rapid tumor growth that phenocopied Cre-mediated genetic deletion of Lkb1. This method will transform our ability to rapidly interrogate gene function during the development of this recalcitrant cancer.

Small molecule compounds targeting the p53 pathway: are we finally making progress?

Abstract Loss of function of p53, either through mutations in the gene or through mutations to other members of the pathway that inactivate wild-type p53, remains a critically important aspect of human cancer development. As such, p53 remains the most commonly mutated gene in human cancer. For these reasons, pharmacologic activation of the p53 pathway has been a highly sought after, yet unachieved goal in developmental therapeutics. Recently progress has been made not only in the discovery of small molecules that target wild-type and mutant p53, but also in the initiation and completion of the first in-human clinical trials for several of these drugs. Here, we review the current literature of drugs that target wild-type and mutant p53 with a focus on small-molecule type compounds. We discuss common means of drug discovery and group them according to their common mechanisms of action. Lastly, we review the current status of the various drugs in the development process and identify newer areas of p53 tumor biology that may prove therapeutically useful.

Synthetic metallochaperone ZMC1 rescues mutant p53 conformation by transporting zinc into cells as an ionophore

p53 is a Zn2+-dependent tumor suppressor inactivated in >50% of human cancers. The most common mutation, R175H, inactivates p53 by reducing its affinity for the essential zinc ion, leaving the mutant protein unable to bind the metal in the low [Zn2+]free environment of the cell. The exploratory cancer drug zinc metallochaperone-1 (ZMC1) was previously demonstrated to reactivate this and other Zn2+-binding mutants by binding Zn2+ and buffering it to a level such that Zn2+ can repopulate the defective binding site, but how it accomplishes this in the context of living cells and organisms is unclear. In this study, we demonstrated that ZMC1 increases intracellular [Zn2+]free by functioning as a Zn2+ ionophore, binding Zn2+ in the extracellular environment, diffusing across the plasma membrane, and releasing it intracellularly. It raises intracellular [Zn2+]free in cancer (TOV112D) and noncancer human embryonic kidney cell line 293 to 15.8 and 18.1 nM, respectively, with half-times of 2–3 minutes. These [Zn2+]free levels are predicted to result in ∼90% saturation of p53-R175H, thus accounting for its observed reactivation. This mechanism is supported by the X-ray crystal structure of the [Zn(ZMC1)2] complex, which demonstrates structural and chemical features consistent with those of known metal ionophores. These findings provide a physical mechanism linking zinc metallochaperone-1 in both in vitro and in vivo activities and define the remaining critical parameter necessary for developing synthetic metallochaperones for clinical use.

Intraoperative Fluid Administration Is Associated With Perioperative Outcomes in Pancreaticoduodenectomy: A Single Center Retrospective Analysis

Recent studies on perioperative fluid administration in patients undergoing major abdominal surgery have suggested that increased fluid loads are associated with worse perioperative outcomes. However, results of retrospective analyses of the relationship between intraoperative fluid (IOF) administration and perioperative outcomes in patients undergoing pancreaticoduodenectomy (PD) are conflicted. We sought to investigate this relationship in patients undergoing PD at our academic center.

Management and Extent of Resection for Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma is the second most common primary liver cancer behind hepatocellular cancer. Although it is an uncommon malignancy, several reports have documented a significant rise in incidence, not only in the United States, but worldwide over the last several decades. As a result, interest in understanding the presentation, diagnosis, natural history, and efficacy of various treatment modalities has increased. This article reviews the clinical presentation, preoperative work-up, surgical management, and outcomes of patients undergoing resection for intrahepatic cholangiocarcinoma. Treatment options in unresectable patients are also reviewed.

Outcomes of microwave ablation for colorectal cancer liver metastases: A single center experience

Surgical management of colorectal cancer liver metastases continues to evolve to optimize oncologic outcomes while maximizing parenchymal preservation. Long‐term data after intraoperative microwave ablation are limited. This study investigates outcomes and patterns of recurrence in patients who underwent intraoperative microwave ablation.

Pilot study of angiogenic response to yttrium-90 radioembolization with resin microspheres.

PURPOSE To investigate the impact of radioembolization with yttrium-90 resin microspheres on the regulation of angiogenesis through observation of serial changes in a spectrum of angiogenic markers and other cytokines after therapy. MATERIALS AND METHODS This prospective pilot study enrolled 22 patients with liver-dominant disease deriving from biopsy-proven hepatocellular carcinoma (HCC) (n = 7) or metastatic colorectal carcinoma (mCRC) (n = 15). Circulating angiogenic markers were measured from serum samples drawn at baseline and at time points after therapy ranging from 6 hours to 120 days. Using multiplex enzyme-linked immunosorbent assay, several classic angiogenesis factors (vascular endothelial growth factor [VEGF], angiopoietin-2 [Ang-2], basic fibroblast growth factor [bFGF], platelet-derived growth factor subunit BB [PDGF-BB], thrombospondin-1 [Tsp-1]) and nonclassic factors (follistatin, leptin, interleukin [IL]-8) were evaluated. RESULTS Increases in cytokine levels ≥ 50% over baseline were observed in more than half of all patients studied for many cytokines, including classic angiogenic factors such as VEGF, Ang-2, and Tsp-1 as well as nonclassic factors IL-8 and follistatin (range, 36%-82% for all cytokines). Baseline cytokine levels in patients with overall survival (OS) < 6 months differed significantly from patients with longer survival for Ang-2 (P = .033) and IL-8 (P = .041). Patients with OS ≤ 6 months exhibited transient increases in VEGF and PDGF-BB after therapy compared with patients with OS > 6 months. CONCLUSIONS Radioembolization is associated with early transient increases in many angiogenic cytokines. In this small sample size, some of these changes were associated with worse OS. This research has important implications for future studies of radioembolization with antiangiogenic therapy performed during and after the procedure.

Evaluation of Hepatic Tumor Response to Yttrium-90 Radioembolization Therapy Using Texture Signatures Generated from Contrast-enhanced CT Images

RATIONALE AND OBJECTIVES The aim of this study was to explore the use of texture features generated from liver computed tomographic (CT) datasets as potential image-based indicators of patient response to radioembolization (RE) with yttrium-90 ((90)Y) resin microspheres, an emerging locoregional therapy for advanced-stage liver cancer. MATERIALS AND METHODS Overall posttherapy survival and percent change in serologic tumor marker at 3 months posttherapy represent the primary clinical outcomes in this study. Thirty advanced-stage liver cancer cases (primary and metastatic) treated with RE over a 3-year period were included. Texture signatures for tumor regions, which were delineated to reveal boundaries with normal regions, were computed from pretreatment contrast-enhanced liver CT studies and evaluated for their ability to classify patient serologic response and survival. RESULTS A series of systematic leave-one-out cross-validation studies using soft-margin support vector machine (SVM) classifiers showed hepatic tumor texton and local binary pattern (LBP) signatures both achieve high accuracy (96%) in discriminating subjects in terms of their serologic response. The image-based indicators were also accurate in classifying subjects by survival status (80% and 93% accuracy for texton and LBP signatures, respectively). CONCLUSIONS Hepatic texture signatures generated from tumor regions on pretreatment triphasic CT studies were highly accurate in differentiating among subjects in terms of serologic response and survival. These image-based computational markers show promise as potential predictive tools in candidate evaluation for locoregional therapy such as RE.

The relationship of perioperative fluid administration to outcomes in colorectal and pancreatic surgery: a review of the literature.

Optimal perioperative fluid administration in major gastrointestinal surgery remains a challenging clinical problem. Traditional dogma of a liberal approach to fluid administration in order to counteract potential hypovolemia and decreased end‐organ perfusion can often result in fluid overload, perhaps negatively impacting perioperative outcomes. This hypothesis has been investigated in several types of gastrointestinal surgery. We discuss the current literature on perioperative fluid administration in colorectal and pancreatic surgery and highlight the controversies that still exist. J. Surg. Oncol. 2015 111:472–477.