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Current approaches for treating cancer are limited, in part, by the inability of drugs to affect the poorly vascularized regions of tumors. We have found that C. novyi-NT in combination with anti-microtubule agents can cause the destruction of both the vascular and avascular compartments of tumors. The two classes of microtubule inhibitors were found to exert markedly different effects. Some agents that inhibited microtubule synthesis, such as HTI-286 and vinorelbine, caused rapid, massive hemorrhagic necrosis when used in combination with C. novyi-NT. In contrast, agents that stabilized microtubules, such as the taxanes docetaxel and MAC-321, resulted in slow tumor regressions that killed most neoplastic cells. Remaining cells in the poorly perfused regions of tumors could be eradicated by C. novyi-NT. Mechanistic studies showed that the microtubule destabilizers, but not the microtubule stabilizers, radically reduced blood flow to tumors, thereby enlarging the hypoxic niche in which C. novyi-NT spores could germinate. A single intravenous injection of C. novyi-NT plus selected anti-microtubule agents was able to cause regressions of several human tumor xenografts in nude mice in the absence of excessive toxicity.

To identify genes that mediate transforming growth factor-β (TGF-β) signaling, a colorectal cancer cell line that was sensitive to the growth inhibitory effects of this cytokine was created. We then determined the global gene expression profiles of these cells, and those of HaCaT human keratinocytes, in the presence and absence of TGF-β. Of the several genes identified in this screen, DEC1 was of particular note in light of the rapidity and consistency of its induction and its potential biochemical activities. We identified a consensus DNA-binding site for DEC1 and showed that DEC1 could repress the transcription of a reporter containing this binding site in its promoter. Finally, both alleles of the DEC1 locus in HaCaT cells were inactivated through targeted homologous recombination. This approach revealed that DEC1 induction was not required for the growth inhibition mediated by TGF-β in this line. However, DEC1 may function in concert with other signaling components to mediate certain biologic effects of TGF-β.

Through exomic sequencing of ten hepatitis C virus (HCV)-associated hepatocellular carcinomas (HCC) and subsequent evaluation of additional affected individuals, we discovered novel inactivating mutations of ARID2 in four major subtypes of HCC (HCV-associated HCC, hepatitis B virus (HBV)-associated HCC, alcohol-associated HCC and HCC with no known etiology). Notably, 18.2% of individuals with HCV-associated HCC in the United States and Europe harbored ARID2 inactivation mutations, suggesting that ARID2 is a tumor suppressor gene that is relatively commonly mutated in this tumor subtype.

Meeting abstracts Recent clinical trials have shown highly promising responses in a subset of patients treated with immune checkpoint inhibitory anti-programmed cell death-1, anti-programmed cell death ligand-1 (PD-1), and anti-cytotoxic T-lymphocyte-associated antigen-4 antibodies (CTLA-4) [[1][1

In the past year, several studies of mice with genetically manipulated Smad genes have caught the attention of cancer researchers. Smad is a family of at least nine genes, each bearing an identifying number (e.g., Smad1, Smad2, and Smad9), and each encoding a protein involved in mediating cellular responses to transforming growth factor β (TGF-β) and related polypeptides. The prototype for this family of ligands was named “transforming growth factor” because it was initially identified as a serum component that stimulated neoplastic-like behavior in fibroblasts. Now we know that it has important roles in the life and death of . . .

We have identified a human homolog of the Xenopus forkhead activin signal transducer-1 (xFAST-1). Although significantly different in sequence from its Xenopus counterpart, hFAST-1 shared with xFAST-1 the ability to bind to human Smad2 and activate an activin response element (ARE). The hFAST-1-dependent activation of ARE was completely dependent on endogenous Smad4 and stimulation by a TGF beta-like ligand. The hFAST-1 protein was shown to bind to a novel DNA motif, TGT (G/T) (T/G)ATT, an exact copy of which was present within the ARE. A single copy of this motif could activate a reporter in a TGF beta-dependent fashion but only when an adjacent Smad-binding element was present in the construct. These data suggest that responses to TGF beta family members may be mediated by a DNA-binding complex formed by hFAST-1, hSmad2, and hSmad4.

Background Traditional imaging techniques for the localization and monitoring of bacterial infections, although reasonably sensitive, suffer from a lack of specificity. This is particularly true for musculoskeletal infections. Bacteria possess a thymidine kinase (TK) whose substrate specificity is distinct from that of the major human TK. The substrate specificity difference has been exploited to develop a new imaging technique that can detect the presence of viable bacteria. Methodology/Principal Findings Eight subjects with suspected musculoskeletal infections and one healthy control were studied by a combination of [124I]FIAU-positron emission tomography and CT ([124I]FIAU-PET/CT). All patients with proven musculoskeletal infections demonstrated positive [124I]FIAU-PET/CT signals in the sites of concern at two hours after radiopharmaceutical administration. No adverse reactions with FIAU were observed. Conclusions/Significance [124I]FIAU-PET/CT is a promising new method for imaging bacterial infections.

The F1–20 protein is a novel neuronal-specific, synapse-associated protein that is expressed nonuniformly in mouse brain. Expression of the F1–20 protein is developmentally regulated in a pattern coincident with active synaptogenesis and synaptic maturation. Here we report the cloning of the cDNA sequence for the F1–20 protein. We found two distinct isoforms of F1–20 cDNA that differed by the presence of 15 additional nucleotides, which does not interrupt the open reading frame. RNase protection analysis and PCR amplification of mouse brain RNA revealed that both isoforms are present in cellular RNA. It is likely that the two F1–20 mRNA isoforms are derived from RNA splicing events utilizing alternative 3′ acceptor sites. Analysis of the deduced amino acid sequence for the complete open reading frame revealed that the predominant F1–20 mRNA encodes an 896 amino acid polypeptide with a molecular weight of 91,319 Da. The deduced amino acid sequence does not contain a signal sequence, or any extensive hydrophobic regions. The deduced amino acid sequence does contain a number of consensus sequences for protein kinases. Searches of the protein and nucleic acid sequence data bases revealed that the F1–20 protein has not been previously characterized at the primary structure level, although a weak similarity was found between rabbit calpastatin and the C-terminal portion of the F1–20 protein. We then determined biochemically that the F1–20 protein is a substrate for Ca(2+)-dependent proteolysis, which is specifically inhibited by calpain inhibitors in vitro. This indicates that the F1–20 protein is a substrate for neuronal calpain. We observed that treatment of a synaptosomal lysate with alkaline phosphatase led to an increase in the electrophoretic mobility of the F1–20 protein, as well as to an increase in the sharpness of the electrophoretic band. This indicates that the F1–20 protein is phosphorylated in vivo.

Previous genetic analyses have suggested that mutations of the genes encoding PI3Kα facilitate invasion and metastasis but have less effect on primary tumor growth. These findings have major implications for therapeutics but have not been factored into pre-clinical drug development designs. Here we show that the inhibition of PI3Kα by newly designed small molecule inhibitors prevented metastasis formation in mice but had much less effect on the growth of subcutaneous xenografts or primary intra-abdominal tumors. These data support the idea that PI3Kα plays an important role in the metastatic process and suggest a more informed strategy for selecting drugs worthy of further development for clinical application.

Yuan Qiao 1* , Xin Huang 1* , Sridhar Nimmagadda 2* , Renyuan Bai 3* , Verena Staedtke 3 , Catherine A. Foss 2 , Ian Cheong 1 , Matthias Holdhoff 1 , Yoshinori Kato 2 , Martin G. Pomper 2 , Gregory J. Riggins 3 , Kenneth W. Kinzler 1 , Luis A. Diaz, Jr 1 , Bert Vogelstein 1 , Shibin Zhou 1 1 The Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute and Sidney Kimmel Cancer Center at the Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA 2 Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA 3 Department of Neurosurgery, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA * These authors contributed equally to this work Keywords: Tumor, Vasculature, Nanoparticle, Inflammation, TNF-α Received: February 28, 2011; Accepted: March 1, 2011; Published: March 1, 2011; Correspondence: Shibin Zhou, e-mail: // // Abstract While nanoparticles have shown great promise as drug carriers in cancer therapy, their effectiveness is critically dependent on the structural characteristics of the tumor vasculature. Here we demonstrate that several agents capable of inducing vascular responses akin to those observed in inflammatory processes enhance the accumulation of nanoparticles in tumors. The vascular-active agents tested in this study included a bacterium, a pro-inflammatory cytokine, and microtubule-destabilizing drugs. Using radiolabeled nanoparticles, we show that such agents can increase the tumor to blood ratio of radioactivity by more than 20-fold compared to nanoparticles alone. Moreover, vascular-active agents dramatically improved the therapeutic effect of nanoparticles containing radioactive isotopes or chemotherapeutic agents. This resulted in cures of animals with subcutaneous tumors and significantly prolonged the survival of animals with orthotopic brain tumors. In principle, a variety of vascular-active agents and macromolecular anticancer formulations can be combined, which makes this approach broadly applicable and particularly suited for the treatment of patients who have failed standard therapies.