Iodide Mumps after Intravascular Administration of a Nonionic Contrast Medium

Swelling of the submandibular, sublingual and/or parotid glands (“iodide mumps”) is an uncommon complication to intravascular administration of contrast material. The etiology remains unclear, but the reaction seems to be idiosyncratic or related to toxic accumulation of iodide in the ductal systems of the salivary glands. The introduction of nonionic contrast media has not eliminated the risk of developing iodide mumps. The first reported case of iodide mumps after intravascular administration of iopromide (Ultravist 300) is presented.

Ultrasound-Guided Renal Biopsy with Biopsy Gun Technique — Efficacy and Complications

One hundred and thirty-one ultrasound-guided renal biopsies performed in 127 patients with automated spring-loaded biopsy technique were evaluated. Adequate tissue for histologic diagnosis was obtained in 92% of the procedures (94% of the patients). The mean glomerular yield was 16.8 glomeruli. Complications were seen in 21% of the patients, 18% having minor and 3% having major complications. Patients with severe hypertension had significantly more complications than the rest of the patients. The rate of complications in patients who had 3 or 4 biopsy passes was not increased compared to patients who had one or 2 biopsy passes. Thus, this study indicates that the risk of complications and the safety of the procedure is not influenced by increasing the number of biopsy passes in order to obtain representative specimens.

Abstract 4021: The class I HDAC inhibitor, mocetinostat, induces expression of PD-L1 and tumor antigen presentation machinery and modifies tumor immune cellular subsets providing a rationale for immune checkpoint inhibitor combinations

Immunotherapy has led to major treatment breakthroughs for a number of cancers including non-small cell lung cancer (NSCLC). Although initial responses to immune checkpoint inhibitors are promising, a significant percentage of patients do not respond or rapidly acquire resistance. Although the mechanisms underlying intrinsic and acquired resistance remain largely unexplained; the expression of programmed cell death-ligand 1 (PD-L1), lack of tumor cell capacity to effectively present neoantigens, and presence of immunosuppressive cellular subsets have been implicated as potential mechanisms. Histone deacetylase (HDAC) inhibitors have emerged as a class of agents that may combat checkpoint inhibitor resistance by reversing immune evasion and eliciting an anti-tumor activity through a multi-faceted immuno-stimulatory mechanism of action. Mocetinostat is a spectrum-selective Class I/IV HDAC inhibitor specifically targeting HDAC-1, -2, -3 and -11. The present studies were designed to explore mocetinostat's effect as an immune-enhancer and ultimately, to evaluate its potential to be used in combination with immune checkpoint inhibitors (e.g., PD-1/PD-L1 antagonists). Specifically, we assessed mocetinostat's effect on the expression of various immunomodulatory factors by tumor cells as well as its effect on immune cell sub-populations in the tumor microenvironment in vivo. Mocetinostat elicited a concentration-dependent increase in PD-L1 mRNA expression which translated into increased PD-L1 surface protein expression in a panel of NSCLC cell lines. In addition, mocetinostat elicited a concentration-dependent increase in expression of MHC-class I related polypeptide-related sequence A (MIC-A) and MIC-B, and cluster of differentiation 86 (CD86). Furthermore, mocetinostat induced expression of several human leukocyte antigen (HLA) gene complex family members including HLA-A, -B, -DRA, and -DPA among others. To determine the effect of mocetinostat on systemic and tumor immune cell subpopulations we treated CT26 tumor-bearing mice. Mocetinostat increased splenic CD4-positive T effector cells and tumor mature cytolytic CD8-postive T cells and at the same time decreased tumor FoxP3-positive T regulatory cells and CD11b/Gr1-positive myeloid-derived suppressor cells (MDSC). These data provide evidence that mocetinostat modulates key immune regulators both in tumor cells as well as in relevant immune cell types in the tumor microenvironment and provides strong rationale for combination with immune checkpoint inhibitors.

Citation Format: David Briere, Niranjan Sudhakar, Lars Engstrom, Jill Hallin, Ruth Tang, Harrah Chiang, Maryland Rosenfeld-Franklin, Peter Olson, James Christensen. The class I HDAC inhibitor, mocetinostat, induces expression of PD-L1 and tumor antigen presentation machinery and modifies tumor immune cellular subsets providing a rationale for immune checkpoint inhibitor combinations. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4021.

Parity-Time Synthetic Phononic Media

Classical systems containing cleverly devised combinations of loss and gain elements constitute extremely rich building units that can mimic non-Hermitian properties, which conventionally are attainable in quantum mechanics only. Parity-time (PT) symmetric media, also referred to as synthetic media, have been devised in many optical systems with the ground breaking potential to create nonreciprocal structures and one-way cloaks of invisibility. Here we demonstrate a feasible approach for the case of sound where the most important ingredients within synthetic materials, loss and gain, are achieved through electrically biased piezoelectric semiconductors. We study first how wave attenuation and amplification can be tuned, and when combined, can give rise to a phononic PT synthetic media with unidirectional suppressed reflectance, a feature directly applicable to evading sonar detection.

MET Exon 14 Mutations in Non-Small-Cell Lung Cancer Are Associated With Advanced Age and Stage-Dependent MET Genomic Amplification and c-Met Overexpression

PURPOSE

Non-small-cell lung cancers (NSCLCs) harboring mutations in MET exon 14 and its flanking introns may respond to c-Met inhibitors. We sought to describe the clinical, pathologic, and genomic characteristics of patients with cancer with MET exon 14 mutations.

PATIENTS AND METHODS

We interrogated next-generation sequencing results from 6,376 cancers to identify those harboring MET exon 14 mutations. Clinical characteristics of MET exon 14 mutated NSCLCs were compared with those of NSCLCs with activating mutations in KRAS and EGFR. Co-occurring genomic mutations and copy number alterations were identified. c-Met immunohistochemistry and real-time polymerase chain reaction to detect exon 14 skipping were performed where sufficient tissue was available.

RESULTS

MET exon 14 mutations were identified in 28 of 933 nonsquamous NSCLCs (3.0%) and were not seen in other cancer types in this study. Patients with MET exon 14-mutated NSCLC were significantly older (median age, 72.5 years) than patients with EGFR-mutant (median age, 61 years; P < .001) or KRAS-mutant NSCLC (median age, 65 years; P < .001). Among patients with MET exon 14 mutations, 68% were women, and 36% were never-smokers. Stage IV MET exon 14-mutated NSCLCs were significantly more likely to have concurrent MET genomic amplification (mean ratio of MET to chromosome 7, 4.3) and strong c-Met immunohistochemical expression (mean H score, 253) than stage IA to IIIB MET exon 14-mutated NSCLCs (mean ratio of MET to chromosome 7, 1.4; P = .007; mean H score, 155; P = .002) and stage IV MET exon 14-wild-type NSCLCs (mean ratio of MET to chromosome 7, 1.2; P < .001; mean H score, 142; P < .001). A patient whose lung cancer harbored a MET exon 14 mutation with concurrent genomic amplification of the mutated MET allele experienced a major partial response to the c-Met inhibitor crizotinib.

CONCLUSION

MET exon 14 mutations represent a clinically unique molecular subtype of NSCLC. Prospective clinical trials with c-Met inhibitors will be necessary to validate MET exon 14 mutations as an important therapeutic target in NSCLC.

Abstract A1-52: Identification of drug-sensitive Notch receptor alterations in human breast cancer

While the Notch pathway is reportedly activated in breast cancer, the molecular mechanisms leading to its aberrant activation remain elusive, hampering the optimal development of Notch inhibitors in the clinics. In an effort to identify predictive biomarkers of response to Notch targeted therapies in breast cancer, we used several computational approaches, including novel algorithms for detecting complex structural rearrangements, to analyze next generation sequencing and related omic datasets from The Cancer Genome Atlas (TCGA) breast cancer cohort. We identified simple mutations and complex rearrangements in NOTCH1, NOTCH2 and NOTCH3 that compromised the function of the PEST domain, a negative regulatory domain controlling the duration of active Notch signaling. Focal amplifications of NOTCH2 and NOTCH3 were also observed, as were heterodimerization or extracellular domain alterations, at lower incidence. Mutations and amplifications often activated the Notch pathway as evidenced by increased expression of canonical Notch target genes, and functional mutations were significantly enriched in the triple negative breast cancer (TNBC) subtype. We also sequenced a panel of breast cancer xenograft models and identified models that harbor functionally equivalent PEST domain alterations. These models were significantly more sensitive to a gamma secretase inhibitor (GSI) compared to models without Notch alterations. Gene expression and functional analyses were performed to study the mechanism of activation through mutation and inhibition by GSI. In summary, we demonstrated that Notch pathway is activated via multiple mutational mechanisms primarily involving the PEST domains of NOTCH1, NOTCH2 and NOTCH3. Collectively, approximately 13% of TNBC exhibits a genetic alteration coupled with pathway up-regulation and these alterations may serve as biomarkers to identify patients most likely to respond to Notch inhibitors.

Citation Format: Kai Wang, Qin Zhang, Danan Li, Keith Ching, Cathy Zhang, Xianxian Zheng, Mark Ozeck, Stephanie Shi, Xiaorong Li, Hui Wang, Paul Rejto, James Christensen, Peter Olson. Identification of drug-sensitive Notch receptor alterations in human breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-52.

PEST domain mutations in Notch receptors comprise an oncogenic driver segment in triple-negative breast cancer sensitive to a γ-secretase inhibitor

PURPOSE

To identify and characterize novel, activating mutations in Notch receptors in breast cancer and to determine response to the gamma secretase inhibitor (GSI) PF-03084014.

EXPERIMENTAL DESIGN

We used several computational approaches, including novel algorithms, to analyze next-generation sequencing data and related omic datasets from The Cancer Genome Atlas (TCGA) breast cancer cohort. Patient-derived xenograft (PDX) models were sequenced, and Notch-mutant models were treated with PF-03084014. Gene-expression and functional analyses were performed to study the mechanism of activation through mutation and inhibition by PF-03084014.

RESULTS

We identified mutations within and upstream of the PEST domains of NOTCH1, NOTCH2, and NOTCH3 in the TCGA dataset. Mutations occurred via several genetic mechanisms and compromised the function of the PEST domain, a negative regulatory domain commonly mutated in other cancers. Focal amplifications of NOTCH2 and NOTCH3 were also observed, as were heterodimerization or extracellular domain mutations at lower incidence. Mutations and amplifications often activated the Notch pathway as evidenced by increased expression of canonical Notch target genes, and functional mutations were significantly enriched in the triple-negative breast cancer subtype (TNBC). PDX models were also identified that harbored PEST domain mutations, and these models were highly sensitive to PF-03084014.

CONCLUSIONS

This work suggests that Notch-altered breast cancer constitutes a bona fide oncogenic driver segment with the most common alteration being PEST domain mutations present in multiple Notch receptors. Importantly, functional studies suggest that this newly identified class can be targeted with Notch inhibitors, including GSIs.

Axitinib and crizotinib combination therapy inhibits bone loss in a mouse model of castration resistant prostate cancer

Background

Castration resistant prostate cancer (CRPC) is a leading cause of cancer-related deaths in men. The primary cause of mortality and morbidity in patients is bone metastases and remodeling resulting in osteoblastic and osteolytic lesions. Recently, cabozantinib, a multi-kinase inhibitor (VEGFR2 and c-MET inhibitor), was shown to have efficacy on bone lesions in patients. In this study we tested multi-kinase inhibitors: axitinib (VEGFR inhibitor) and crizotinib (c-MET inhibitor) in a combination trial in mice models.

Methods

VCaP-Luc cells were grown as subcutaneous implants in intact and castrated NOD-SCID-gamma (NSG) mice to confirm the androgen dependency. For bone metastasis model two cohorts of NSG mice (castrated and intact) received orthotopic injection of VCaP-Luc cells into the bone marrow cavity of left tibia. Mice were monitored weekly for tumor growth using bioluminescence imaging. Animals were randomized into 4 groups based on the tumor bioluminescence signal: vehicle, crizotinib alone, axitinib alone, crizotinib and axitinib in combination. Animals were imaged weekly by in vivo 2-D X-ray imaging to monitor bone remodeling. At the end of the study animals were euthanized and both tibias were extracted for ex vivo high-resolution 3-D micro-computed tomography (μCT) imaging.

Results

Subcutaneous model showed that androgen stimulation may be helpful but not essential for the growth of VCaP-Luc cells. VCaP-Luc cells grown intra-tibially in intact animals caused extensive remodeling of bone with mixed osteoblastic (bone formation) and osteolytic (bone matrix dissolution) lesions. The osteoblastic lesions were predominant and at times extended beyond the tibial shaft into the surrounding tissue. In contrast, only osteolytic lesions were prominent throughout the study in castrated animals. Treatment with crizotinib alone reduced the osteolytic lesions in castrated animals. Axitinib alone reduced the osteoblastic lesions in the intact animals. Combination therapy with axitinib and crizotinib remarkably inhibited the tibial remodeling by VCaP-Luc cells which resulted in a significant reduction of both osteoblastic and osteolytic lesions.

Conclusion

Our data show that combined inhibition of c-MET and VEGFR can be beneficial for treatment of metastatic bone disease in CRPC and that the drugs act on two different stages of the disease.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-742) contains supplementary material, which is available to authorized users.

Abstract 1909: Identification and characterization of microRNA-134 as a novel receptor tyrosine kinase-regulated tumor suppressive hub in glioblastoma

Receptor tyrosine kinases (RTKs) are co-deregulated in a majority of glioblastoma (GBM), the most common and most deadly brain tumor. In this study, we uncovered microRNA-134 (miR-134) as a novel tumor suppressive hub that is co-regulated by multiple RTKs via MAPK and KLF4 and that acts via regulation of KRAS and STAT5B expressions. Using microRNA microarrays and qRT-PCR, we screened for microRNAs that are co-regulated by multiple RTKs in GBM. We found that miR-134 was one such microRNA that is downregulated by the activation of MET, EGFR, and PDGFR, the three most commonly deregulated RTKs in GBM. Using a combination of pharmacology, promoter analysis, transcription factor functional and rescue approaches and ChIP/qPCR, we uncovered the MAPK pathway and the transcriptional repressor KLF4 as mediators of the effects of RTKs on miR-134 repression. We then measured the expression of miR-134 and found that it was downregulated in human GBM tumors and GBM stem cells (GSCs) and that it inversely correlated with the activation levels of MET, EGFR, and PDGFR in the tumors. We demonstrated that miR-134 inhibits GBM cell and GSC proliferation, survival, and in vivo xenograft growth, as well as GSC self-renewal and stemness. We uncovered the oncogenes KRAS and STAT5B as direct targets of miR-134 with immunoblots and 3′UTR reporter assays, and showed with rescue experiments that they mediate miR-134 tumor suppressive effects. Thereafter, using a series of molecular and functional assays we established direct links and dependencies between RTKs, KLF4, miR-134, KRAS/STAT5B and malignancy in vitro and in vivo. Importantly, we also found that miR-134 induction is required for the anti-tumor effects of small molecule RTK inhibitors. Altogether, our extensive study identified miR-134 as a novel RTK-regulated tumor-suppressive hub that mediates RTK and RTK-inhibitor effects on GBM malignancy by controlling KRAS and STAT5B. These findings shed new light onto the molecular and functional interactions between RTKs and microRNAs and uncover opportunities for exploiting these interactions for therapeutic purposes.

Citation Format: Ying Zhang, Jungeun Kim, Adam C. Mueller, Bijan Dey, Yanzhi Yang, Daehee Lee, Jan Hachmann, Sanjo Finderle, Deric M. Park, James Christensen, David Schiff, Benjamin Purow, Anindya Dutta, Roger Abounader. Identification and characterization of microRNA-134 as a novel receptor tyrosine kinase-regulated tumor suppressive hub in glioblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1909. doi:10.1158/1538-7445.AM2014-1909

Audit of a 5-year radiographic protocol for assessment of mandibular third molars before surgical intervention

OBJECTIVES

To perform an audit of a three-step protocol for radiographic examination of mandibular third molars before surgery.

METHODS

1769 teeth underwent surgery. A standardized three-step radiographic protocol was followed: (1) panoramic imaging (PAN), (2) stereoscanography (SCAN) and (3) CBCT. If there was overprojection between the tooth and the canal in PAN, SCAN was performed. If the tooth was determined to be in close contact with the canal in SCAN, CBCT was performed. Close contact between the tooth and the canal was assessed in all images, and patient-reported sensory disturbances from the alveolar inferior nerve were recorded after surgery. The relation between the final radiographic examination and sensory disturbances was determined. Logistic regression analysis tested whether signs for a close contact in PAN/SCAN could predict no bony separation between the tooth and canal in CBCT.

RESULTS

46% of teeth underwent PAN, 31% underwent SCAN and 23% underwent CBCT as the final examination. 21% underwent all three radiographic examinations. 53/76% of teeth with close relation to the canal in PAN/SCAN showed no bony separation in CBCT; if there was close relation in PAN/SCAN, there was 1.6/4.3 times higher probability that no bony separation existed in CBCT. 16 cases of sensory disturbances were recorded: 4 operations were based on PAN, 8 on SCAN and 4 on CBCT.

CONCLUSIONS

The radiographic protocol was in general followed. SCAN was superior to PAN in predicting no bony separation between the tooth and the canal in CBCT, and there was no relation between sensory disturbances and radiographic method.

Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars

OBJECTIVES

The aim of this prospective clinical study was to derive the absolute and relative costs of cone beam CT (CBCT) and panoramic imaging before removal of an impacted mandibular third molar. Furthermore, the study aimed to analyse the influence of different cost-setting scenarios on the outcome of the absolute and relative costs and the incremental costs related to surgery.

METHODS

A randomized clinical trial compared complications following surgical removal of a mandibular third molar, where the pre-operative diagnostic method had been panoramic imaging or CBCT. The resources implied in the two methods were measured with health economic tools. The primary outcome was total costs defined as the sum of absolute imaging costs and incremental surgery-related costs. The basic variables were capital costs, operational costs, radiological costs, radiographic costs, overheads and patient resource utilization. Differences in resources used for surgical and post-surgical management were calculated for each patient.

RESULTS

Converted to monetary units, the total costs for panoramic imaging equalized €49.29 and for CBCT examination €184.44. Modifying effects on this outcome such as differences in surgery time, treatment time for complications, pre- and post-surgical medication, sickness absence, specialist treatment and hospitalization were not statistically significant between the two diagnostic method groups.

CONCLUSIONS

Costs for a CBCT examination were approximately four times the costs for panoramic imaging when used prior to removal of a mandibular third molar. The use of CBCT did not change the resources used for surgery, post-surgical treatment and patient complication management.

Multiple receptor tyrosine kinases converge on microRNA-134 to control KRAS, STAT5B, and glioblastoma

Receptor tyrosine kinases (RTKs) are co-deregulated in a majority of glioblastoma (GBM), the most common and most deadly brain tumor. We show that the RTKs MET, EGFR, and PDGFR regulate microRNA-134 (miR-134) in GBM. We find that miR-134 is downregulated in human tumors and cancer stem cells and that its expression inversely correlates with the activation of MET, EGFR, and PDGFR. We demonstrate that miR-134 inhibits cancer cell and stem-cell proliferation, survival, and xenograft growth, as well as cancer stem-cell self-renewal and stemness. We identify KRAS and STAT5B as targets of miR-134, and establish molecular and functional links between RTKs, miR-134, KRAS/STAT5B and malignancy in vitro and in vivo. We show that miR-134 induction is required for the anti-tumor effects of RTK inhibitors. We also uncover the molecular pathways through which RTKs regulate miR-134 expression and demonstrate the involvement of MAPK signaling and the KLF4 transcription factor. We therefore identify miR-134 as a novel RTK-regulated tumor-suppressive hub that mediates RTK and RTK-inhibitor effects on GBM malignancy by controlling KRAS and STAT5B.

Preschool behavioral problems in children prenatally exposed to antiepileptic drugs - a follow-up study

We studied the association between maternal epilepsy, antiepileptic drug (AED) treatment, and behavioral problems in preschool children. In the Danish National Birth Cohort, we identified 4- to 5-year-old children whose mothers had epilepsy and received AED treatment (n=133) or not (n=304) during pregnancy and compared them with randomly selected children whose mothers did not have epilepsy (n=1193). The children's behavioral problems were assessed by the use of the Strengths and Difficulties Questionnaire (SDQ). Children prenatally exposed to AEDs more often had an abnormal total SDQ score as compared with children of women without epilepsy (odds ratio (OR)=4.8 (95% CI: 1.9-12.1)) and as compared with children of women with epilepsy who were not treated with AEDs during their pregnancy (OR=4.0 (95% CI: 1.3-12.8)). In conclusion, prenatal AED exposure may increase the risk of behavioral problems in preschool children even after adjustments for potential confounders and maternal epilepsy.

Lessons from (S)-6-(1-(6-(1-methyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)ethyl)quinoline (PF-04254644), an inhibitor of receptor tyrosine kinase c-Met with high protein kinase selectivity but broad phosphodiesterase family inhibition leading to myocardial degeneration in rats

The hepatocyte growth factor (HGF)/c-Met signaling axis is deregulated in many cancers and plays important roles in tumor invasive growth and metastasis. An exclusively selective c-Met inhibitor (S)-6-(1-(6-(1-methyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)ethyl)quinoline (8) was discovered from a highly selective high-throughput screening hit via structure-based drug design and medicinal chemistry lead optimization. Compound 8 had many attractive properties meriting preclinical evaluation. Broad off-target screens identified 8 as a pan-phosphodiesterase (PDE) family inhibitor, which was implicated in a sustained increase in heart rate, increased cardiac output, and decreased contractility indices, as well as myocardial degeneration in in vivo safety evaluations in rats. Compound 8 was terminated as a preclinical candidate because of a narrow therapeutic window in cardio-related safety. The learning from multiparameter lead optimization and strategies to avoid the toxicity attrition at the late stage of drug discovery are discussed.

Antitumor Efficacy of the Dual PI3K/mTOR Inhibitor PF-04691502 in a Human Xenograft Tumor Model Derived from Colorectal Cancer Stem Cells Harboring a PIK3CA Mutation

PIK3CA (phosphoinositide-3-kinase, catalytic, alpha polypeptide) mutations can help predict the antitumor activity of phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway inhibitors in both preclinical and clinical settings. In light of the recent discovery of tumor-initiating cancer stem cells (CSCs) in various tumor types, we developed an in vitro CSC model from xenograft tumors established in mice from a colorectal cancer patient tumor in which the CD133+/EpCAM+ population represented tumor-initiating cells. CD133+/EpCAM+ CSCs were enriched under stem cell culture conditions and formed 3-dimensional tumor spheroids. Tumor spheroid cells exhibited CSC properties, including the capability for differentiation and self-renewal, higher tumorigenic potential and chemo-resistance. Genetic analysis using an OncoCarta™ panel revealed a PIK3CA (H1047R) mutation in these cells. Using a dual PI3K/mTOR inhibitor, PF-04691502, we then showed that blockage of the PI3K/mTOR pathway inhibited the in vitro proliferation of CSCs and in vivo xenograft tumor growth with manageable toxicity. Tumor growth inhibition in mice was accompanied by a significant reduction of phosphorylated Akt (pAKT) (S473), a well-established surrogate biomarker of PI3K/mTOR signaling pathway inhibition. Collectively, our data suggest that PF-04691502 exhibits potent anticancer activity in colorectal cancer by targeting both PIK3CA (H1047R) mutant CSCs and their derivatives. These results may assist in the clinical development of PF-04691502 for the treatment of a subpopulation of colorectal cancer patients with poor outcomes.

Abstract 1679A: HLTF gene silencing predicts sensitivity to lysosomal autophagy inhibitors in cancer cells

Autophagy inhibition with hydroxychloroquine (HCQ), either alone or when combined with other anticancer agents, is cytotoxic to only in a subset of human cancer cell lines. Clinical trials involving HCQ in cancer patients are underway, but predictive biomarkers to guide the development of autophagy inhibitors are not available. To identify determinants of sensitivity to HCQ, an mRNA microarray analysis of HCQ-sensitive compared to HCQ- resistant colon cancer and lung cancer cell lines identified helicase-like transcription factor(HLTF) as the number one most down regulated gene in HCQ-sensitive cell lines. In a larger panel of cancer cell lines HLTF promoter methylation correlated with silenced expression and sensitivity to HCQ. Forced expression of HLTF by transfection or treatment with a demethylating agent conferred resistance to HCQ-sensitive cell lines. Knockdown of HLTF in HCQ-resistant cell lines conferred sensitivity. To determine the mechanism that links HLTF to lysosomal autophagy inhibition, we posed the hypothesis that HCQ-related ROS produced DNA damage that was repaired by HLTF. Lysosomal autophagy inhibition with HCQ produced reactive oxygen species (ROS) irrespective of HLTF status. Cotreatment with an ROS scavenger but not cathepsin inhibitors mitigated HCQ associated cytotoxicity in HLTF silenced cells. DNA damage was observed at 100-fold lower HCQ concentrations in HLTF silenced cell lines than in HLTF expressed cells. Knockdown of pol eta, a low fidelity DNA polymerase involved in translesion synthesis, completely abrogated HLTF-associated resistance to HCQ. HLTF expression and caspase inhibition but not either alone completely abrogated all DNA damage and cytotoxicity associated with HCQ in HLTF silenced cells. These results outline a potentially new mechanistic pathway that links lysosomal autophagy inhibition with ROS-mediated DNA damage and secondary caspase-dependent apoptosis, which can be prevented by intact HLTF-pol eta translesion synthesis activity. Next, combinations of HCQ with PI3K/mTOR, FAK, or IGFR1 inhibitors currently under clinical investigation were tested in cells with silenced or expressed HLTF. Additive cytotoxicity with HCQ was observed only in cell lines with silenced HLTF irrespective of the inhibitor combination tested. Finally low expression of HLTF as measured by immunohistochemistry predicted responders in a preliminary cohort of colon cancer patients treated on a phase I clinical trial of FOLFOX/bevacizumab and HCQ. Given that previous clinical studies have determined that HLTF gene silencing is prevalent in 20-40% of many epithelial malignancies, these results provide rationale for development of HLTF gene silencing as a first predictive biomarker for autophagy inhibitors that could be applied to a broad subset of human cancers.

Citation Format: Shengfu Piao, Arabinda Samanta, Xiao-hong Ma, Quentin Mcafee, Ben Wilkins, James Christensen, Peter O'Dwyer, Ravi K. Amaravadi. HLTF gene silencing predicts sensitivity to lysosomal autophagy inhibitors in cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1679A. doi:10.1158/1538-7445.AM2013-1679A

Hepatocyte growth factor sensitizes brain tumors to c-MET kinase inhibition

PURPOSE

The receptor tyrosine kinase (RTK) c-MET and its ligand hepatocyte growth factor (HGF) are deregulated and promote malignancy in cancer and brain tumors. Consequently, clinically applicable c-MET inhibitors have been developed. The purpose of this study was to investigate the not-well-known molecular determinants that predict responsiveness to c-MET inhibitors and to explore new strategies for improving inhibitor efficacy in brain tumors.

EXPERIMENTAL DESIGN

We investigated the molecular factors and pathway activation signatures that determine sensitivity to c-MET inhibitors in a panel of glioblastoma and medulloblastoma cells, glioblastoma stem cells, and established cell line-derived xenografts using functional assays, reverse protein microarrays, and in vivo tumor volume measurements, but validation with animal survival analyses remains to be done. We also explored new approaches for improving the efficacy of the inhibitors in vitro and in vivo.

RESULTS

We found that HGF coexpression is a key predictor of response to c-MET inhibition among the examined factors and identified an ERK/JAK/p53 pathway activation signature that differentiates c-MET inhibition in responsive and nonresponsive cells. Surprisingly, we also found that short pretreatment of cells and tumors with exogenous HGF moderately but statistically significantly enhanced the antitumor effects of c-MET inhibition. We observed a similar ligand-induced sensitization effect to an EGF receptor small-molecule kinase inhibitor.

CONCLUSIONS

These findings allow the identification of a subset of patients that will be responsive to c-MET inhibition and propose ligand pretreatment as a potential new strategy for improving the anticancer efficacy of RTK inhibitors.

Contrast agents for quantitative microCT of lung tumors in mice

The identification and quantitative evaluation of lung tumors in mouse models is challenging and an unmet need in preclinical arena. In this study, we developed a noninvasive contrast-enhanced microCT (μCT) method to longitudinally evaluate and quantitate lung tumors in mice. Commercially available μCT contrast agents were compared to determine the optimal agent for visualization of thoracic blood vessels and lung tumors in naïve mice and in non-small-cell lung cancer models. Compared with the saline control, iopamidol and iodinated lipid agents provided only marginal increases in contrast resolution. The inorganic nanoparticulate agent provided the best contrast and visualization of thoracic vascular structures; the density contrast was highest at 15 min after injection and was stable for more than 4 h. Differential contrast of the tumors, vascular structures, and thoracic air space by the nanoparticulate agent enabled identification of tumor margins and accurate quantification. μCT data correlated closely with traditional histologic measurements (Pearson correlation coefficient, 0.995). Treatment of ELM4-ALK mice with crizotinib yielded 65% reduction in tumor size and thus demonstrated the utility of quantitative μCT in longitudinal preclinical trials. Overall and among the 3 agents we tested, the inorganic nanoparticulate product was the best commercially available contrast agent for visualization of thoracic blood vessels and lung tumors. Contrast-enhanced μCT imaging is an excellent noninvasive method for longitudinal evaluation during preclinical lung tumor studies.

Perfect imaging, epsilon-near zero phenomena and waveguiding in the scope of nonlocal effects

Plasmons in metals can oscillate on a sub-wavelength length scale and this large-k response constitutes an inherent prerequisite for fascinating effects such as perfect imaging and intriguing wave phenomena associated with the epsilon-near-zero (ENZ) regime. While there is no upper cut-off within the local-response approximation (LRA) of the plasma polarization, nonlocal dynamics suppress response beyond ω/v(F), where v(F) is the Fermi velocity of the electron gas. Nonlocal response has previously been found to pose limitations to field-enhancement phenomena. Accounting for nonlocal hydrodynamic response, we show that perfect imaging is surprisingly only marginally affected by nonlocal properties of a metal slab, even for a deep subwavelength case and an extremely thin film. Similarly, for the ENZ response we find no indications of nonlocal response jeopardizing the basic behaviors anticipated from the LRA. Finally, our study of waveguiding of gap plasmons even shows a positive nonlocal influence on the propagation length.

Tunable acoustic double negativity metamaterial

Man-made composite materials called “metamaterials” allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative.

Epidemiology of methicillin-resistant Staphylococcus aureus carrying the novel mecC gene in Denmark corroborates a zoonotic reservoir with transmission to humans

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated (HA), community-associated (CA) and livestock-associated (LA) infections. Recently, the discovery of human and bovine MRSA isolates carrying a new mecA gene homologue, mecA(LGA251) (now designated mecC), has caused concern because they are not detected by conventional, confirmatory tests for MRSA. Very little is known about their frequency, epidemiology and possible transmission between livestock and humans. In this study, the epidemiology of the mecC isolates in Denmark was investigated by screening the national collections of MRSA cases (from 1988 onwards) and S. aureus bacteraemia cases (from 1958 onwards). Isolates carrying mecC were only recovered infrequently before 2003 (n = 2) but now seem to be increasing, with 110 cases in 2003-2011. Clinical data on mecC-carrying MRSA demonstrated that mecC-MRSA were primarily community-acquired (CA-MRSA) and affected persons typically living in rural areas, being older than other CA-MRSA patients. Among 22 cases in Region Zealand, four reported contact with cattle and sheep. Two of these persons lived on farms with livestock positive for mecC-carrying MRSA, sharing spa type (t843), MLVA (MT429) and PFGE pattern with the human isolates. These observations indicate that mecC-carrying MRSA can be exchanged between humans and ruminants.

Classifying Workload with Eye Movements in a Complex Task

Eye movements and pupil size have been used to assess workload in previous research. However, the results presented in the literature vary, and the tasks have been too simple at times or the experimental conditions (e.g. lighting) too tightly controlled to determine if the use of eye data to assess workload is useful in real-world contexts. This research investigates the use of ten eye movement, eyelid, or pupil related metrics as input to support vector machines for classifying workload in a complex task. The results indicate that both pupil size and percentage of eye closure are useful for predicting workload. Further, the combination of the two metrics increases the robustness and accuracy of the workload predictions.