A Novel Lipid Nanoparticle NBF-006 Encapsulating Glutathione S-Transferase P siRNA for the Treatment of KRAS-Driven Non-small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancers, and KRAS mutations occur in 25% to 30% of NSCLC. Our approach to developing a therapeutic with the potential to target KRAS-mutant NSCLC was to identify a new target involved in modulating signaling proteins in the RAS pathway. Glutathione S-transferase P (GSTP), known as a phase II detoxification enzyme, has more recently been identified as a modulator of MAPK-related cell signaling pathways.

Anti-HSP47 siRNA lipid nanoparticle ND-L02-s0201 reverses interstitial pulmonary fibrosis in preclinical rat models.

ND-L02-s0201 is a lipid nanoparticle encapsulating an siRNA which inhibits expression of heat shock protein 47 (HSP47), a collagen-specific chaperone. Accumulated evidence demonstrates a close association between increased level of HSP47 and excessive accumulation of collagen in fibrotic diseases. Our objective was to test ND-L02-s0201 efficacy in preclinical lung fibrosis models and characterise the downstream histological and functional consequences of inhibiting the expression of HSP47.

Anti-miR-17 therapy delays tumorigenesis in MYC-driven hepatocellular carcinoma (HCC).

Hepatocellular carcinoma (HCC) remains a significant clinical challenge with few therapeutic options. Genomic amplification and/or overexpression of the MYC oncogene is a common molecular event in HCC, thus making it an attractive target for drug therapy. Unfortunately, currently there are no direct drug therapies against MYC.

Lipid Nanoparticle-Mediated Delivery of Anti-miR-17 Family Oligonucleotide Suppresses Hepatocellular Carcinoma Growth.

Hepatocellular carcinoma (HCC) is one of the most common human malignancies with poor prognosis and urgent unmet medical need. Aberrant expression of multiple members of the miR-17 family are frequently observed in HCC, and their overexpression promotes tumorigenic properties of HCC cells. However, whether pharmacologic inhibition of the miR-17 family inhibits HCC growth remains unknown.

Shift of microRNA profile upon glioma cell migration using patient-derived spheroids and serum-free conditions.

Glioblastoma multiforme (GBM) is the most frequent malignant primary brain tumor. A major reason for the overall median survival being only 14.6 months is migrating tumor cells left behind after surgery.

Dissociation of gemcitabine chemosensitization by CHK1 inhibition from cell cycle checkpoint abrogation and aberrant mitotic entry.

In order to determine the relative contribution of checkpoint abrogation and subsequent aberrant mitotic entry to gemcitabine chemosensitization by CHK1 inhibition, we established a model utilizing the CDK inhibitors roscovitine or purvalanol A to re-establish cell cycle arrest and prevent aberrant mitotic entry in pancreatic cancer cells treated with gemcitabine and the CHK inhibitor AZD7762. In this study, we report that the extent of aberrant mitotic entry, as determined by flow cytometry for the mitotic marker phospho-Histone H3 (Ser10), did not reflect the relative sensitivities of pancreatic cancer cell lines to gemcitabine chemosensitization by AZD7762. In addition, re-establishing gemcitabine-induced cell cycle arrest either pharmacologically, with roscovitine or purvalanol A, or genetically, with cyclin B1 siRNA, did not inhibit chemosensitization uniformly across the cell lines.

miR-21 Inhibition Reduces Liver Fibrosis and Prevents Tumor Development by Inducing Apoptosis of CD24+ Progenitor Cells.

miR-21 is upregulated in hepatocellular carcinoma and intrahepatic cholangiocarcinoma, where it is associated with poor prognosis. Here, we offer preclinical evidence that miR-21 offers a therapeutic and chemopreventive target in these liver cancers. In mice with hepatic deletion of Pten, anti-miR-21 treatment reduced liver tumor growth and prevented tumor development.

Anti-miR-21 Suppresses Hepatocellular Carcinoma Growth via Broad Transcriptional Network Deregulation.

Unlabelled: Hepatocellular carcinoma (HCC) remains a significant clinical challenge with few therapeutic options available to cancer patients. MicroRNA 21-5p (miR-21) has been shown to be upregulated in HCC, but the contribution of this oncomiR to the maintenance of tumorigenic phenotype in liver cancer remains poorly understood. We have developed potent and specific single-stranded oligonucleotide inhibitors of miR-21 (anti-miRNAs) and used them to interrogate dependency on miR-21 in a panel of liver cancer cell lines.

Identification of the endosomal sorting complex required for transport-I (ESCRT-I) as an important modulator of anti-miR uptake by cancer cells.

Mechanisms of unassisted delivery of RNA therapeutics, including inhibitors of microRNAs, remain poorly understood. We observed that the hepatocellular carcinoma cell line SKHEP1 retains productive free uptake of a miR-21 inhibitor (anti-miR-21). Uptake of anti-miR-21, but not a mismatch (MM) control, induces expression of known miR-21 targets (DDAH1, ANKRD46) and leads to dose-dependent inhibition of cell growth.

Anti-miR182 reduces ovarian cancer burden, invasion, and metastasis: an in vivo study in orthotopic xenografts of nude mice.

High-grade serous ovarian carcinoma (HGSOC) is a fatal disease, and its grave outcome is largely because of widespread metastasis at the time of diagnosis. Current chemotherapies reduce tumor burden, but they do not provide long-term benefits for patients with cancer. The aggressive tumor growth and metastatic behavior characteristic of these tumors demand novel treatment options such as anti-microRNA treatment, which is emerging as a potential modality for cancer therapy.

Phase I dose-escalation study of AZD7762, a checkpoint kinase inhibitor, in combination with gemcitabine in US patients with advanced solid tumors.

Purpose: AZD7762 is a Chk1 kinase inhibitor which increases sensitivity to DNA-damaging agents, including gemcitabine. We evaluated the safety of AZD7762 monotherapy and with gemcitabine in advanced solid tumor patients.

Experimental Design: In this Phase I study, patients received intravenous AZD7762 on days 1 and 8 of a 14-day run-in cycle (cycle 0; AZD7762 monotherapy), followed by AZD7762 plus gemcitabine 750-1,000 mg/m(2) on days 1 and 8, every 21 days, in ascending AZD7762 doses (cycle 1; combination therapy).

Sensitization of pancreatic cancer stem cells to gemcitabine by Chk1 inhibition.

Checkpoint kinase 1 (Chk1) inhibition sensitizes pancreatic cancer cells and tumors to gemcitabine. We hypothesized that Chk1 inhibition would sensitize pancreatic cancer stem cells to gemcitabine. We tested this hypothesis by using two patient-derived xenograft models (designated J and F) and the pancreatic cancer stem cell markers CD24, CD44, and ESA.

Discovery of checkpoint kinase inhibitor (S)-5-(3-fluorophenyl)-N-(piperidin-3-yl)-3-ureidothiophene-2-carboxamide (AZD7762) by structure-based design and optimization of thiophenecarboxamide ureas.

Checkpoint kinases CHK1 and CHK2 are activated in response to DNA damage that results in cell cycle arrest, allowing sufficient time for DNA repair. Agents that lead to abrogation of such checkpoints have potential to increase the efficacy of such compounds as chemo- and radiotherapies. Thiophenecarboxamide ureas (TCUs) were identified as inhibitors of CHK1 by high throughput screening.

Synthesis and evaluation of triazolones as checkpoint kinase 1 inhibitors.

Checkpoint kinase 1 (Chk1, CHEK1) is a Ser/Thr protein kinase that plays a key role in mediating the cellular response to DNA-damage. Synthesis and evaluation of a previously described class of Chk1 inhibitors, triazoloquinolones/triazolones (TZs) is further described herein. Our investigation of structure-activity relationships led to the identification of potent inhibitors 14c, 14h and 16e.

Assessment of chk1 phosphorylation as a pharmacodynamic biomarker of chk1 inhibition.

Purpose: Chk1 inhibitors, such as AZD7762, are in clinical development in combination with cytotoxic agents for the treatment of solid tumors, including pancreatic cancers. To maximize the likelihood of their clinical success, it is essential to optimize drug scheduling as well as pharmacodynamic biomarkers in preclinical models.

Experimental Design: We tested multiple schedules of administration of gemcitabine and AZD7762 on the survival of pancreatic cancer cells.

Discovery of a novel class of triazolones as checkpoint kinase inhibitors--hit to lead exploration.

Checkpoint Kinase-1 (Chk1, CHK1, CHEK1) is a Ser/Thr protein kinase that mediates cellular responses to DNA-damage. A novel class of Chk1 inhibitors, triazoloquinolones/triazolones (TZ's) was identified by high throughput screening. The optimization of these hits to provide a lead series is described.

Mechanism of radiosensitization by the Chk1/2 inhibitor AZD7762 involves abrogation of the G2 checkpoint and inhibition of homologous recombinational DNA repair.

The median survival for patients with locally advanced pancreatic cancer treated with gemcitabine and radiation is approximately 1 year. To develop improved treatment, we have combined a Chk1/2-targeted agent, AZD7762, currently in phase I clinical trials, with gemcitabine and ionizing radiation in preclinical pancreatic tumor models. We found that in vitro AZD7762 alone or in combination with gemcitabine significantly sensitized MiaPaCa-2 cells to radiation.

In vitro and in vivo radiation sensitization of human tumor cells by a novel checkpoint kinase inhibitor, AZD7762.

Purpose: Inhibition of checkpoint kinase 1 has been shown to enhance the cytotoxicity of DNA-damaging targeted chemotherapy through cell cycle checkpoint abrogation and impaired DNA damage repair. A novel checkpoint kinase 1/2 inhibitor, AZD7762, was evaluated for potential enhancement of radiosensitivity for human tumor cells in vitro and in vivo xenografts.

Experimental Design: Survival of both p53 wild-type and mutant human cell lines was evaluated by clonogenic assay.

Chk1 inhibition after replicative stress activates a double strand break response mediated by ATM and DNA-dependent protein kinase.

Checkpoint kinase 1 (Chk1) regulates cell cycle checkpoints and DNA damage repair in response to genotoxic stress. Inhibition of Chk1 is an emerging strategy for potentiating the cytotoxicity of chemotherapeutic drugs. Here, we demonstrate that AZD7762, an ATP -competitive Chk1/2 inhibitor induces gammaH2AX in gemcitabine-treated cells by altering both dynamics and stability of replication forks, allowing the firing of suppressed replication origins as measured by DNA fiber combing and causing a dramatic increase in DNA breaks as measured by comet assay.

Preclinical pharmacokinetic/pharmacodynamic models to predict synergistic effects of co-administered anti-cancer agents.

Purpose: Pharmacokinetic/pharmacodynamic (PK/PD) models have been shown to be useful in predicting tumor growth rates in mouse xenografts. We applied novel PK/PD models to the published anticancer combination therapies of tumor growth inhibition to simulate synergistic changes in tumor growth rates. The parameters from the PK/PD model were further used to estimate clinical doses of the combination.

AZD7762, a novel checkpoint kinase inhibitor, drives checkpoint abrogation and potentiates DNA-targeted therapies.

Insights from cell cycle research have led to the hypothesis that tumors may be selectively sensitized to DNA-damaging agents resulting in improved antitumor activity and a wider therapeutic margin. The theory relies on the observation that the majority of tumors are deficient in the G1-DNA damage checkpoint pathway resulting in reliance on S and G2 checkpoints for DNA repair and cell survival. The S and G2 checkpoints are regulated by checkpoint kinase 1, a serine/threonine kinase that is activated in response to DNA damage; thus, inhibition of checkpoint kinase 1 signaling impairs DNA repair and increases tumor cell death.

Keeping checkpoint kinases in line: new selective inhibitors in clinical trials.

Background: Checkpoint kinase 1 (Chk1), a serine/threonine kinase, functions as a regulatory kinase in cell cycle progression and is a critical effector of the DNA-damage response. Inhibitors of Chk1 are known to sensitise tumours to a variety of DNA-damaging agents and increase efficacy in preclinical models.

Objective: The most advanced agents are now in Phase I clinical trials; the preclinical profiles of these drugs are compared and contrasted, together with a discussion of some of the opportunities and challenges facing this potentially revolutionary approach to cancer therapy.

DNA damage detection and repair pathways--recent advances with inhibitors of checkpoint kinases in cancer therapy.

Insights from cell cycle research have led to the hypothesis that tumors may be selectivity sensitized to DNA-damaging agents, resulting in improved antitumor activity and a wider therapeutic margin. The theory relies primarily on the observation that the majority of tumors are deficient in the G(1)-DNA damage checkpoint pathway, resulting in reliance on S and G(2) phase checkpoints for DNA repair and cell survival. The S and G(2) phase checkpoints are predominantly regulated by checkpoint kinase 1; thus, inhibition of checkpoint kinase 1 signaling impairs DNA repair and increases tumor cell death.

Discovery of a novel class of 2-ureido thiophene carboxamide checkpoint kinase inhibitors.

Checkpoint kinase-1 (Chk1, CHEK1) is a Ser/Thr protein kinase that mediates the cellular response to DNA-damage. A novel class of 2-ureido thiophene carboxamide urea (TCU) Chk1 inhibitors is described. Inhibitors in this chemotype were optimized for cellular potency and selectivity over Cdk1.

Inhibitors of checkpoint kinases: from discovery to the clinic.

Checkpoint kinase 1 (CHK1) is a member of the serine/ threonine kinase family. CHK1 functions as a regulatory kinase in cell-cycle progression and is the main effector of theDNA-damage response within the cell. Over the past few years, a large number of novel inhibitors of CHK1 have been discovered that encompass an enormous area of chemical space and diversity and, in more recent reports, many of these inhibitors have been demonstrated preclinically to sensitize tumors to a wide variety of DNA-damaging agents.