Christiane Thallinger

Identification of differential and functionally active miRNAs in both anaplastic lymphoma kinase (ALK)+ and ALK− anaplastic large-cell lymphoma

Aberrant anaplastic lymphoma kinase (ALK) expression is a defining feature of many human cancers and was identified first in anaplastic large-cell lymphoma (ALCL), an aggressive non-Hodgkin T-cell lymphoma. Since that time, many studies have set out to identify the mechanisms used by aberrant ALK toward tumorigenesis. We have identified a distinct profile of micro-RNAs (miRNAs) that characterize ALCL; furthermore, this profile distinguishes ALK+ from ALK− subtypes, and thus points toward potential mechanisms of tumorigenesis induced by aberrant ALK. Using a nucleophosmin-ALK transgenic mouse model as well as human primary ALCL tumor tissues and human ALCL-derived cell lines, we reveal a set of overlapping deregulated miRNAs that might be implicated in the development and progression of ALCL. Importantly, ALK+ and ALK− ALCL could be distinguished by a distinct profile of “oncomirs”: Five members of the miR-17–92 cluster were expressed more highly in ALK+ ALCL, whereas miR-155 was expressed more than 10-fold higher in ALK− ALCL. Moreover, miR-101 was down-regulated in all ALCL model systems, but its forced expression attenuated cell proliferation only in ALK+ and not in ALK− cell lines, perhaps suggesting different modes of ALK-dependent regulation of its target proteins. Furthermore, inhibition of mTOR, which is targeted by miR-101, led to reduced tumor growth in engrafted ALCL mouse models. In addition to future therapeutical and diagnostic applications, it will be of interest to study the physiological implications and prognostic value of the identified miRNA profiles.

Esophageal Cancer: A Critical Evaluation of Systemic Second-Line Therapy

The objective of this article was to review clinical trials that used antineoplastic second-line chemotherapy and/or targeted therapies in patients with esophageal cancer after first-line therapy. Computerized (MEDLINE) and manual searches were performed to identify articles published on this topic between 1996 and 2011. Twenty-five published trials and four abstracts presented at scientific meetings were identified. A total of 10 trials included only patients with squamous cell carcinomas (SCCs), four focused exclusively on adenocarcinoma (AC), the remaining 15 studies included both SCC and AC. The majority of trials (17 of 29) used docetaxel in combination with platinum analogs, eight used single-agent cytotoxic chemotherapy, and six evaluated targeted therapies. The numbers of patients were relatively small, ranging from eight to 55 patients. The response rates were generally low (between 0% and 39%), with only two small studies reporting objective responses of 50% and 63%, respectively. Time to progression ranged from 1.4 to 6.2 months, and the overall survival was disappointing at 4.0 to 11.4 months. Approximately 40% of patients who experience progressive disease after first-line chemotherapy are able to undergo second-line treatment. On the basis of data published so far, no standard second-line therapy has emerged. Future research will need to focus on individual therapy strategies such as genetic receptor mutations to increase the therapeutic outcome.

PDGFR blockade is a rational and effective therapy for NPM-ALK-driven lymphomas

Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkins lymphoma found in children and young adults. ALCLs frequently carry a chromosomal translocation that results in expression of the oncoprotein nucleophosmin–anaplastic lymphoma kinase (NPM-ALK). The key molecular downstream events required for NPM-ALK–triggered lymphoma growth have been only partly unveiled. Here we show that the activator protein 1 family members JUN and JUNB promote lymphoma development and tumor dissemination through transcriptional regulation of platelet-derived growth factor receptor-β (PDGFRB) in a mouse model of NPM-ALK–triggered lymphomagenesis. Therapeutic inhibition of PDGFRB markedly prolonged survival of NPM-ALK transgenic mice and increased the efficacy of an ALK-specific inhibitor in transplanted NPM-ALK tumors. Notably, inhibition of PDGFRA and PDGFRB in a patient with refractory late-stage NPM-ALK+ ALCL resulted in rapid, complete and sustained remission. Together, our data identify PDGFRB as a previously unknown JUN and JUNB target that could be a highly effective therapy for ALCL.

Mcl-1 Is a Novel Therapeutic Target for Human Sarcoma: Synergistic Inhibition of Human Sarcoma Xenotransplants by a Combination of Mcl-1 Antisense Oligonucleotides with Low-Dose Cyclophosphamide

Purpose: Little is known about the role that Mcl-1, an antiapoptotic Bcl-2 family member, plays in solid tumor biology and susceptibility to anticancer therapy. We observed that the Mcl-1 protein is widely expressed in human sarcoma cell lines of different histological origin (n = 7). Because the expression of antiapoptotic Bcl-2 family proteins can significantly contribute to the chemoresistance of human malignancies, we used an antisense strategy to address this issue in sarcoma. Experimental Design: SCID mice (n = 6/group) received s.c. injections of SW872 liposarcoma cells. After development of palpable tumors, mice were treated by s.c.-implanted miniosmotic pumps prefilled with saline or antisense or universal control oligonucleotides (20 mg/kg/day for 2 weeks). On days 2, 6, and 10, mice were treated with low-dose cyclophosphamide (35 mg/kg i.p) or saline control. During the experiments, tumor weight was assessed twice weekly by caliper measurements. On day 14, animals were sacrificed. Tumors were weighed and fixed in formalin for immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling analysis. Results: Mcl-1 antisense oligonucleotides specifically reduced Mcl-1 protein expression but produced no reduction in tumor weight compared with saline-treated control animals. Cyclophosphamide monotreatment caused only modest tumor weight reduction compared with saline control. However, use of Mcl-1 antisense oligonucleotides combined with cyclophosphamide clearly enhanced tumor cell apoptosis and significantly reduced tumor weight by more than two-thirds compared with respective control treatments. Conclusion: A combination of Mcl-1 antisense oligonucleotides with low-dose cyclophosphamide provides a synergistic antitumor effect and might qualify as a promising strategy to overcome chemoresistance in human sarcoma.

The proto-oncoprotein c-Fos negatively regulates hepatocellular tumorigenesis

Hepatocytes adopt an invasive and metastatic phenotype caused by the cooperation of transforming growth factor (TGF)-β and oncogenic Ha-Ras. In the initial phase of this process, c-Fos is rapidly induced by TGF-β, but then decreases to undetectable levels. Here, we investigated the functional implications of c-Fos activation and its contribution to hepatocellular tumorigenesis. By employing conditional c-Fos expression, we observed that continuous activation of c-Fos and consequently AP-1 activity leads to depolarization of differentiated murine epithelial hepatocytes. Most remarkably, this change in morphology was associated with inhibition of proliferation and induction of cell death. Coexpression of antiapoptotic Bcl-XL or scavenging of reactive oxygen species was sufficient to prevent the c-Fos-mediated phenotype. In contrast, the cooperation of c-Fos with oncogenic Ha-Ras or a Ras mutant selectively activating the MAPK pathway even enhanced c-Fos-induced effects. Showing the negative role in hepatocellular tumorigenesis, c-Fos repressed oncogenic Ras-driven anchorage-independent growth in vitro and strongly suppressed tumour formation in vivo. Taken together, we demonstrate that c-Fos modulates plasticity of epithelial hepatocytes and acts tumour suppressive in neoplastic hepatocytes by stimulating cell cycle inhibition and cell death.

Suppression of human melanoma tumor growth in SCID mice by a human high molecular weight-melanoma associated antigen (HMW-MAA) specific monoclonal antibody

The lack of efficacy of available therapies for the treatment of malignant melanoma has emphasized the need to develop novel therapeutic strategies to prevent melanoma growth. We have tested whether the anti‐HMW‐MAA mAb 225.28S is able to inhibit human melanoma tumor growth in SCID mice because in vitro data suggested that this antigen plays a role in spreading, migration and invasion of melanoma cells. Tumors were established by subcutaneous injection of the human melanoma cell line 518A2 into SCID mice. When tumors reached a size of 5 mm, the mAb 225.28S was administered intravenously 4 times in 3 day intervals at 100 μg/injection. Within 14 days after the first administration of the mAb 225.28S, tumor growth was reduced by 52% as compared to control mice. Three hundred and seven genes of >20,000 genes contained on the GeneChip were changed in their expression level at least 2‐fold after administration of the mAb 225.28S. The encoded proteins were mostly components or modifiers of the extracellular matrix, tumor suppressors, and melanogenesis associated proteins. Surprisingly, the administration of the control mAb that did not lead to a significant tumor growth inhibition in vivo resulted in the modulation of two‐thirds of these genes. This is the first report of suppression of human melanoma tumor growth in SCID mice by the mAb 225.28S. Our results suggest that anti‐HMW‐MAA mAbs may represent useful reagents to apply passive immunotherapy to patients with malignant melanoma.

CCI-779 plus Cisplatin Is Highly Effective against Human Melanoma in a SCID Mouse Xenotranplantation Model

Background: This study set out to investigate the antitumor effects of a treatment strategy combining the mTOR inhibitor CCI-779 with cisplatin in vitro and in a human melanoma SCID mouse model. Methods: In vitro 518A2, Mel-JUSO or 607B cell lines were incubated with CCI-779, cisplatin and CCI-779 plus cisplatin. Based on these results, a 4-group, parallel, controlled experimental study design was initiated in vivo. SCID mice were injected with melanoma cells, and after the development of tumors the mice received daily injections of CCI-779 or solvent. On treatment days 2 and 6 cisplatin or mock solution were administered. Results: In vitro a synergistic antitumor effect was observed for the treatment regimen of CCI-779 plus cisplatin. In SCID mice after 2 weeks of therapy with CCI-779 plus cisplatin 4 of 6 tumors of the 518A2 cell line were completely eradicated. In the two remaining 518A2 xenografts this treatment strategy reduced the tumor weight by 94 ± 9% compared to solvent. CCI-779 plus cisplatin also exerted a significant antitumor effect in Mel-JUSO and 607B xenografts compared to mock-treated animals. Conclusion: We provide circumstantial evidence that the use of CCI-779 plus cisplatin might qualify as a promising strategy in the treatment of human melanoma.

New perspectives in stem cell research: beyond embryonic stem cells

Although stem cell research is a rather new field in modern medicine, media soon popularized it. The reason for this hype lies in the potential of stem cells to drastically increase quality of life through repairing aging and diseased organs. Nevertheless, the essence of stem cell research is to understand how tissues are maintained during adult life. In this article, we summarize the various types of stem cells and their differentiation potential in vivo and in vitro. We review current clinical applications of stem cells and highlight problems encountered when going from animal studies to clinical practice. Furthermore, we describe the current state of induced pluripotent stem cell technology and applications for disease modelling and cell replacement therapy.

Suppression of mTOR complex 2-dependent AKT phosphorylation in melanoma cells by combined treatment with rapamycin and LY294002

Background  Inhibition of mTOR complex 1 (mTORC1) with rapamycin leads to phosphorylation of AKT in some cancer cells, with unknown biological consequences. The role of this phosphorylation in melanoma is unknown, although preliminary clinical data indicate poor activity of rapalogues in melanoma.

Influence of adjunctive classical homeopathy on global health status and subjective wellbeing in cancer patients — A pragmatic randomized controlled trial

OBJECTIVES The use of complementary and alternative medicine has increased over the past decade. The aim of this study was to evaluate whether homeopathy influenced global health status and subjective wellbeing when used as an adjunct to conventional cancer therapy. DESIGN In this pragmatic randomized controlled trial, 410 patients, who were treated by standard anti-neoplastic therapy, were randomized to receive or not receive classical homeopathic adjunctive therapy in addition to standard therapy. The study took place at the Medical University Vienna, Department of Medicine I, Clinical Division of Oncology. MAIN OUTCOME MEASURES The main outcome measures were global health status and subjective wellbeing as assessed by the patients. At each of three visits (one baseline, two follow-up visits), patients filled in two different questionnaires. RESULTS 373 patients yielded at least one of three measurements. The improvement of global health status between visits 1 and 3 was significantly stronger in the homeopathy group by 7.7 (95% CI 2.3-13.0, p=0.005) when compared with the control group. A significant group difference was also observed with respect to subjective wellbeing by 14.7 (95% CI 8.5-21.0, p<0.001) in favor of the homeopathic as compared with the control group. Control patients showed a significant improvement only in subjective wellbeing between their first and third visits. CONCLUSION Results suggest that the global health status and subjective wellbeing of cancer patients improve significantly when adjunct classical homeopathic treatment is administered in addition to conventional therapy.