Purpose: Glioblastoma is a highly malignant, invariably fatal brain tumor for which effective pharmacotherapy remains an unmet medical need.Experimental Design: Screening of a compound library of 160 synthetic and natural toxic substances identified the antihelmintic niclosamide as a previously unrecognized candidate for clinical development. Considering the cellular and interindividual heterogeneity of glioblastoma, a portfolio of short-term expanded primary human glioblastoma cells (pGBM; n ¼ 21), common glioma lines (n ¼ 5), and noncancer human control cells (n ¼ 3) was applied as a discovery platform and for preclinical validation. Pharmacodynamic analysis, study of cell-cycle progression, apoptosis, cell migration, proliferation, and on the frequency of multipotent/self-renewing pGBM cells were conducted in vitro, and orthotopic xenotransplantation was used to confirm anticancer effects in vivo.Results: Niclosamide led to cytostatic, cytotoxic, and antimigratory effects, strongly reduced the frequencies of multipotent/self-renewing cells in vitro, and after exposure significantly diminished the pGBMs' malignant potential in vivo. Mechanism of action analysis revealed that niclosamide simultaneously inhibited intracellular WNT/CTNNB1-, NOTCH-, mTOR-, and NF-kB signaling cascades. Furthermore, combinatorial drug testing established that a heterozygous deletion of the NFKBIA locus in glioblastoma samples could serve as a genomic biomarker for predicting a synergistic activity of niclosamide with temozolomide, the current standard in glioblastoma therapy.Conclusions: Together, our data advocate the use of pGBMs for exploration of compound libraries to reveal unexpected leads, for example, niclosamide that might be suited for further development toward personalized clinical application. Clin Cancer Res; 19(15); 4124-36. Ó2013 AACR.

Cellular heterogeneity, for example, the intratumoral coexistence of cancer cells with and without stem cell characteristics, represents a potential root of therapeutic resistance and a significant challenge for modern drug development in glioblastoma (GBM). We propose here that activation of the innate immune system by stimulation of innate immune receptors involved in antiviral and antitumor responses can similarly target different malignant populations of glioma cells. We used short‐term expanded patient‐specific primary human GBM cells to study the stimulation of the cytosolic nucleic acid receptors melanoma differentiation‐associated gene 5 (MDA5) and retinoic acid‐inducible gene I (RIG‐I). Specifically, we analyzed cells from the tumor core versus “residual GBM cells” derived from the tumor resection margin as well as stem cell‐enriched primary cultures versus specimens without stem cell properties. A portfolio of human, nontumor neural cells was used as a control for these studies. The expression of RIG‐I and MDA5 could be induced in all of these cells. Receptor stimulation with their respective ligands, p(I:C) and 3pRNA, led to in vitro evidence for an effective activation of the innate immune system. Most intriguingly, all investigated cancer cell populations additionally responded with a pronounced induction of apoptotic signaling cascades revealing a second, direct mechanism of antitumor activity. By contrast, p(I:C) and 3pRNA induced only little toxicity in human nonmalignant neural cells. Granted that the challenge of effective central nervous system (CNS) delivery can be overcome, targeting of RIG‐I and MDA5 could thus become a quintessential strategy to encounter heterogeneous cancers in the sophisticated environments of the brain. STEM Cells 2013;31:1064–1074

Purpose Investigation of clonal heterogeneity may be key to understanding mechanisms of therapeutic failure in human cancer. However, little is known on the consequences of therapeutic intervention on the clonal composition of solid tumors. Experimental Design Here, we used 33 single cell-derived subclones generated from five clinical glioblastoma specimens for exploring intra- and inter-individual spectra of drug resistance profiles in vitro. In a personalized setting, we explored whether differences in pharmacological sensitivity among subclones could be employed to predict drug-dependent changes to the clonal composition of tumors. Results Subclones from individual tumors exhibited a remarkable heterogeneity of drug resistance to a library of potential anti-glioblastoma compounds. A more comprehensive intra-tumoral analysis revealed that stable genetic and phenotypic characteristics of co-existing subclones could be correlated with distinct drug sensitivity profiles. The data obtained from differential drug response analysis could be employed to predict clonal population shifts within the naïve parental tumor in vitro and in orthotopic xenografts. Furthermore, the value of pharmacological profiles could be shown for establishing rational strategies for individualized secondary lines of treatment. Conclusions Our data provide a previously unrecognized strategy for revealing functional consequences of intra-tumor heterogeneity by enabling predictive modeling of treatment-related subclone dynamics in human glioblastoma.

Conflicting data exist about the expression of L1 cell adhesion molecule (L1-CAM) in clear cell renal cell carcinoma (ccRCC). To determine the clinical usefulness of L1-CAM as a therapeutic or prognostic marker molecule in renal cancer patients, we analyzed its expression on a cohort of 282 renal cell carcinoma (RCC) patients. L1-CAM expression was found in 49.5% of 282 renal cancer tissues. Importantly, L1-CAM expression in patients with ccRCC was associated with significantly shorter patient survival time. We further present evidence that L1-CAM was involved in the resistance against therapeutic reagents like rapamycin, sunitinib and cisplatin. The downregulation of L1-CAM expression decreased renal cancer cell proliferation and reduced the expression of cyclin D1. In addition, we found out that Von Hippel-Lindau (VHL) deficiency was accompanied by a downregulation of the transcription factor PAX8 and L1-CAM. In normal renal tissue, PAX8 and L1-CAM were co-expressed in collecting duct cells. Importantly, the downregulation of PAX8 by small interfering RNA increased the expression of L1-CAM and concomitantly induced the migration of renal cancer cells. Furthermore, we observed in 65.3% of 282 RCC patients a downregulation of PAX8 expression. With chromatin immunoprecipitation analysis, we additionally demonstrate that PAX8 can bind to the promoter of L1-CAM and we further observed that the downregulation of PAX8 was accompanied by increased L1-CAM expression in a high fraction of ccRCC patients. In summary, we show that VHL and PAX8 are involved in the regulation of L1-CAM in renal cancer and L1-CAM represents an important therapeutic and prognostic marker protein for the treatment of ccRCC.

PAX transcription factors play an important role during development and carcinogenesis. In this study, we investigated PAX2 protein levels in melanocytes and melanoma cells by Western Blot and immunofluorescence analysis and characterized the role of PAX2 in the pathogenesis of melanoma. In vitro we found weak PAX2 protein expression in keratinocytes and melanocytes. Compared to melanocytes increased PAX2 protein levels were detectable in melanoma cell lines. Interestingly, in tissue sections of melanoma patients nuclear PAX2 expression strongly correlated with nuclear atypia and the degree of prominent nucleoli, indicating an association of PAX2 with a more atypical cellular phenotype. In addition, with chromatin immunoprecipitation assay, PAX2 overexpression and PAX2 siRNA we present compelling evidence that PAX2 can regulate ADAM10 expression, a metalloproteinase known to play important roles in melanoma metastasis. In human tissue samples we found co-expression of PAX2 and ADAM10 in melanocytes of benign nevi and in melanoma cells of patients with malignant melanoma. Importantly, the downregulation of PAX2 by specific siRNA inhibited the anchorage independent cell growth and decreased the migratory and invasive capacity of melanoma cells. Furthermore, the downregulation of PAX2 abrogated the chemoresistance of melanoma cells against cisplatin, indicating that PAX2 expression mediates cell survival and plays important roles during melanoma progression.

The full coding region of the murine dopamine transporter (mDAT) cDNA was cloned by PCR with a sense primer derived from the partial mDAT gene sequence and an antisense primer deduced from the rat dopamine transporter cDNA. The mDAT cDNA encodes a typical member of the family of Na+- and Cl--dependent neurotransmitter transporters with 99.2; 93.4 and 85.4% amino acid identity to the rat, human and bovine DATs, respectively. Functional expression of the mDAT cDNA in transiently transfected human embryonic kidney (HEK293) cells exhibited the typical pharmacological features of a dopamine transporter. [3H]dopamine uptake through the mDAT was inhibited with high potency by GBR12909 (IC50 = 5.2 nM) and not significantly affected by 100 nM desipramine. [3H]dopamine uptake also was inhibited through increasing concentrations of dopamine (IC50 = 0.93 microM) or 1-methyl-4-phenylpyridinium (MPP+; IC50 = 13.2microM).

Viscum album, Cuticular Waxes, Flavonol Aglycones Cuticular waxes of Viscum album ssp. album contain oleanolic acid as main constituent, accompanied by aliphatic compounds like alkanes, esters and primary alcohols. A number of flavonol aglycones (methyl ethers of quercetin and kaempferol) have also been identified. Seasonal changes in amount and composition of cuticular waxes and the presence of flavonol aglycones are described and the ecophysiological significance of flavonoids on the surface of the mistletoe is briefly discussed.

Dovitinib is safe in patients with recurrent GBM and showed efficacy in only some patients unselected for target expression. The recommended phase II dose of 300 mg would be substantially lower than the recently established MTD in systemic cancer patients. Further personalized trials are recommended.